ANTI-AGING FIREWALLS
THE SCIENCE AND TECHNOLOGY OF LONGEVITY

A comprehensive document for the benefit of people interested in living very long healthy lives and who are willing to adapt emerging knowledge personally to do so. And, for the health professionals who serve them.

By Vincent E. Giuliano[1]

Updated biweekly, more or less. Last update August 27, 2010.[2]

What’s new August 27, 2010: I updated discussion of the Increasing mTOR signalling candidate theory of aging today based on new research that lends credance to this theory. I have also added several hyperlinks to blog entries where they are particularly relevant to the discussion. Most-recent blog postings include: * Curcumin, cancer and longevity, * Neurogenesis, curcumin and longevity, * PGC-1alpha and exercise, * Skin Cancer immunotherapies, * Contrarian research findings: newly-identified aging villain substances; calorie restriction longevity is not due to calorie restriction, * Turning P53 on in cancer cells, * Diabetes Part 2: Lifestyle, dietary and supplement interventions, * Diabetes Part I: Biology and molecular dynamics of diabetes, * Alzheimer's disease studies validate anti-aging firewalls suggestions, * Induced pluripotent stem cells - developments on the road to big-time utilization, * Three years exploring longevity science, * HSP70 to the rescue, * AMPK and longevity, * Stress, exercise and telomere lengths, * Humanin, health and aging, * The free radical theory of aging. Is it really a theory of aging?, * Ghrelin hunger, obesity and aging, * Back to blueberries, * Calorie restriction mimetics - focus on avocado extract, * Is acetaminophen an anti-aging drug? Probably not, * A near-term application for iPSCs - making cell lines for drug testing, * Epigenetics, inflammation, cancer, immune system, neurological and cardiovascular disease and aging, * Something new about P21, an old familiar gene - it blocks limb and organ regeneration, * Draft of American Aging Society Presentation - Towards a Systems Theory of Aging, * Melanoma research update, and * Contrarian current research outcomes. On May 7 2010, I integrated what had been a candidate theory of aging Epigenomic Changes In DNA Methylation and Histone Acetylation into the main discussion of the 13th theeory of aging Programmed Epigenomic Changes. Recent blog postings include: * Alzheimer's Disease research update, * Extra-virgin olive oil , * The PROOF Centre of Excellence, * Towards a systems view of aging, * Harnessing the engines of finance and commerce for life-extension, * Progress in stem cell oncolytic virotherapy, * DNA Methyltransferases, stem cell proliferation and differentiation, * More on DNA repair strategies, * What does resveratrol do?, * Telomerase activators - what do they really do?, * Induced pluripotent stem cells - second-rate stem cells so far, * Setting the record straight on three favorite approaches to longevity, * Believing news reports and scientific publications, * Another piece of DAF-16 research, * What are aging, life-extension and anti-aging?, * Niacin or niacinamide supplementation - good or bad idea?, * SIRT1, the hypoxic response, autophagy and hormesis, * Visit with Leonard Guarante, * SIRT1, mTOR, NF-kappaB and resveratrol , * Cell import and export traffic control signaling, * Telomeres and telomerase in Induced Pluripotent stem cells - not what we thought, * Recent diabetes-related clinical trials , * Fucoidan, * The social cost of Alzheimer's disease and late-life dementia, * Vitamin D3 and the immune response, * Sestrins, longevity and cancers, * BDNF gene -- personality, mental balance, dementia, aging and epigenomic imprinting, * DNA repair cleanup failure - a root cause for cancers?, * Joy and sadness of aging - and the impacts of longevity, * New views of Alzheimer's disease and new approaches to treating it, * iPSCs, telomerase, and closing the loop in the stem cell supply chain, * Genome-wide association studies, * "I have never seen a doctor," and * MicroRNAs in cancers and aging, and back-to-the-nematode.

I have been posting some important and longer blog posts recently and updating this treatise less frequently. Started in late January 2009, the blog now includes 308 substantive posts and 580 comments. Also, I have started including selected links from this treatise to blog entries that amplify on particular relevant points.

I have moved older What’s New items, those prior to Feb 15 2010, to the end of this document to reduce up-front clutter. They can be found here.

I. INTRODUCTION

There are several major theories about the underlying causes of what we call aging and age-related causes of death, each with its own school of proponents. This paper outlines fourteen such theories and comments on how each theory relates to primary diseases of aging such as cancers, cardiovascular diseases and Alzheimer’s disease. It then goes on to suggest a practical protective “firewall” against the biochemical processes underlying each aging theory through dietary supplementation and lifestyle modifications. The idea is that each theory of aging points to certain underlying biological processes. Through slowing, preventing or even reversing these processes, it may be possible to slow, prevent or even partially reverse aging. The practical objective is not only living longer but also living free of age-related problems and diseases.

The theories and major causes of age-related death I treat are:

1. Oxidative Damage
2. Cell DNA Damage
3. Mitochondrial Damage
4. Tissue Glycation
5. Lipofuscin Accumulation
6. Chronic Inflammation
7. Immune System Compromise
8. Neurological Degeneration
9. Declines in Hormone Levels
10. Susceptibility to Cancers
11. Susceptibility to Cardiovascular Disease
12. Telomere Shortening and Damage
13. Programmed Epigenomic Changes
14. Stem Cell Supply Chain Breakdown

With aging, people tend to become more and more vulnerable to certain diseases and disorders related to aging. Sooner or later one of these diseases or disorders leads to death. Nobody dies of “old age” per se, but up to this point everybody dies before reaching the age of 123. The theories are concerned with the why and how of death coming so certainly in this fixed time frame. I first outline how each of the theories characterizes increasing susceptibility to key diseases and disorders with increasing age. Then I describe the corresponding protective “firewalls” that I have identified and personally employ.

Since I first drafted this treatise I have added an additional six candidate theories of aging which are described later in this treatise here. There is much research evidence behind each of these theories and bodies of disease knowledge. Each appears to have its strong basis for validity. These theories overlap each other in complex ways. Which one is correct? Probably all of them. They are like the different descriptions of an elephant given by blind men who each feel only a different part of the beast. I prefer to view them not as competitors but as synergistic, as parts of a larger systems perspective on aging yet to be developed. As time goes on more and more links among these theories are becoming known. I report on many of these links ain my blog and also in updated discussions in this treatise.

Suceptablity to disease is a function of genetic background, constitutional history and environmental factors. How these factors interplay to create most diseases and degenerative conditions of old age is in many cases only poorly understood. The firewalls described here cannot be guaranteed to prevent or cure any disease. Nontheless, for healthy people with good genes, I believe the firewalls significantly decrease the probabilities of contracting or becoming debilitated from most of the worst diseases associated with aging at any period of age. Of course I have to add that sooner or later, one or the other of the disease and deterioriation processes will get everybody. My objective is to make that time later. So, my purpose here is to explain and justify some practical approaches that I have been using in an effort to retard my aging, not to provide medical advice.

The human body is extremely complicated and still mostly unknown territory. Even for what is known, I can't cover any individual topic in real depth. Fortunately, the state of knowledge in the areas I touch on here is rapidly developing. I have been updating this on-line treatise weekly or biweekly since the first web draft in May 2008. In that time frame I have added two new theories of aging to the original twelve and have identified several additional firewall supplements. I have added a large number of comments, clarificatory explanations and literature references. I have also created the blog counterpart to this treatise and generally add new postings to the blog daily. I It has 196 substantive postings as of November 9, 2009. And, following current research frontiers, I have identified six additional candidate theories of aging. I discuss these in a final section of this treatise.

II. THEORIES OF AGING

I briefly characterize each of the above-mentioned theories of aging and age-related death, and in some cases touch on how they are related one to another. Further, I outline how these theories explain the processes underlying the most serious diseases that eventually kill older people.

1. Oxidative Damage

The most classical theory of aging is that it is the result of accumulative damage to tissues due to oxidation. Free radicals (ROS or Reactive Oxygen Species) are produced as a result of natural metabolism, by exposure to UV and X-rays, by exposure to certain toxic chemicals including heavy metals, and by consuming certain foods. ROS ions steal electrons from lipids in cell membranes, a process called lipid peroxidation. A chain of damaging events can be let lose from a single ROS molecule as unstable fatty acid radicals propagating in tissues and within cells produce other unstable radicals. The result can be cell death, damage to DNA or mitochondrial DNA, mangled chromosomes, protein cross-linking, cell apoptosis (suicide), genetic mutations, mutated germ cells and other forms of cell havoc. The damage can show up in many ways including skin erythema, hair loss, atherosclerosis and other forms of vascular damage, internal bleeding, cataracts, cancers, hypertension, type 2 diabetes, weakened immune systems, sterility, mutations in offspring, cancers, Alzheimer's disease, premature aging and death. Up to a few years ago, most students of aging thought that oxidative damage was the primary cause of aging. The newer theories of aging continue to see oxidative damage as very important in the aging process, but part of a larger picture.[3] For example, oxidation is now seen to play a role in inhibiting the rate of renewal of neural cells. The biologicL pathways impacted by oxidative damage are becoming better understood, such as its effect on chromatin remodeling and pro-inflammatory signal transduction(ref)(ref).

A contrarian view of ROS, claiming that they are part of signaling mitochondrial hormesis and that therefore their elimination using antioxidants is life-shortening, can be found in this blog post.

To the Oxidative Damage Firewall

2. Cell DNA Damage

Cell mutations can cause or lead to age-related deaths. An important form of oxidative damage can be in the DNA of cells. Environmental toxins, cigarette smoke and even some antibiotics and anti-inflammatory medications can also contribute to DNA damage.  There are multiple kinds of DNA damage including single-strand breaks and double-strand breaks (ref) (ref). Even without extraordinary exposure, in the course of a normal good day a person may have a million or more events of DNA damage occur in his or her body. Consequences can include cell apoptosis, failure to reproduce, abnormal tissue reproduction, reproductive errors leading to cancers, and premature cell senescence. The list of age-related maladies resulting from genetic damage is long including immunodeficiency, rheumatoid arthritis, cancers of all kinds, arteriosclerosis, and chronic diseases such as chronic fatigue. It appears that DNA damage is also the source of a number of neuro-degenerative diseases including Parkinson’s disease and Alzheimer's disease. Since an important form of DNA damage is oxidative damage, the DNA mutation theory of aging is not independent from the oxidative damage theory, and in fact it is closely related to several of the other theories as well.

In response to this challenge, cells have evolved numerous repair strategies. Some such strategies are very clever and some still are being discovered. I discussed one such line of defense against an important form of DNA damage, double-strand breaks, in my March 2010 blog entry DNA repair cleanup failure - a root cause for cancers? I discuss four more strategies used by the body for DNA repair in the subsequent blog entry More on DNA repair strategies.

To the Cell DNA Damage Firewall

3. Mitochondrial Damage

Mitochondria are tiny organelles within cells responsible for producing the cell’s source of chemical energy known as adenosine triphosphate (ATP). Many researchers believe that decline in the integrity of mitochondrial DNA is a root cause of aging and that maintaining mitochondrial health is central for longevity. Mitochondria, have their own DNA which is extremely subject to mutation such as resulting from attack by ROS. At least 40 diseases have been identified that involve pathology of mitochondrial functioning. They can affect brain and other nerve cells, kidneys, eyes, ears, the pancreas, and the liver. Also, damage to mitochondrial DNA can come about through insufficiency of certain micronutrients like zink and copper, and deficiencies of Vitamin D, C, E, B12, B6, niacin, and folic acid(ref). See also the candidate theory of aging based on micronutrient triage.

Cells have mechanisms for repair of damaged DNA and mitochondrial DNA, but these have their own side effects. There is a DNA repair enzyme known as NADH. However, repair results in depletion of NADH and of ATP. ATP depletion is believed to be one of the most critical factors leading to necrosis or cell apoptosis.

Mitochondria play additional critical roles in the cell life and reproductive cycle including roles involving cell signaling, growth, differentiation and death. They can be the sources of many important signals relating to cancers, neurological diseases such as Parkinson’s, cardiovascular diseases, type 2 diabetes, and optical neurological problems. Presence of oxidative conditions in a cell can signal the mitochondria to generate signals to other parts of the cell leading to cell apoptosis. It is thought that selective inhibition of this chain could be one means of retarding aging. The signaling relationships between mitochondrial DNA and regular cellular DNA is one example of the systems relationships between the various theories of aging. And it points out how addressing one “cause” of aging can sometimes also mitigate several others as well.

To the Mitochondrial Damage Firewall

4. Tissue Glycation

Exponents of the glycation theory of aging believe that mitigation of tissue glycation (cross linking of tissue proteins with sugars) could contribute to raising the effective upper limit of human life spans. Glycation is a process involving a sugar molecule such as fructose or glucose bonding to a protein or lipid molecule without the involvement of an enzyme. Glycation may occur either inside the body or be present in foods consumed such as in browned meats, baked goods or french fries. Cross-linking compounds can also be introduced into the body by smoking or chewing cured tobacco. Known as the Maillard reaction, glycation leads to molecular cross-linking and polymerization and the development of brown-color products known as Advanced Glycation Endproducts (AGEs). The brown of toast and burnt crusts on roasted meat are examples of AGEs. A simplistic way of thinking about it is that glycation cooks tissues in an older person’s body rendering them dysfunctional and dangerous to their neighboring tissues.

Body levels of AGEs increase with age and depend on the kinds of food eaten as well as internal bodily processes that eliminate them. The result of AGEs can be self-propagating systemic or "silent" tissue inflammation. AGEs are recognized by cell RAGE receptors which result in the production of cytokine chemicals that can induce unwanted and potentially deadly inflammation in blood vessels, nerve, liver and other tissues. Atherosclerosis can be a consequence. AGEs are responsible for much bodily mischief related to aging leading to deterioration of function and structure of organs. They play important roles in diabetes, atherosclerosis, vascular disease, kidney failure, and neuropathy including Alzheimer's disease.

The presence of AGEs also appears to negatively impact on immune system functioning. Diabetes in particular appears to have its roots due to glycation and people with high blood sugar levels are particularly susceptible to glycation. Glycation and associated inflammation is believed to be a major contributor to microangiopathy. Glycation and oxidation seem to some extent to go hand in hand and there is evidence that the presence of one increases the susceptibility to the other. The presence of AGEs in swollen lysomes in a glycated tissue can result in a multifold increase in the rate of production of free radicals compared to that in an unclycated tissue. Moreover, glycation and oxidation can conspire with each other to produce disease effects such as renal failure.

To the Tissue Glycation Firewall

5. Lipofuscin Accumulation

Control of levels of lipofuscin is another important component of an anti-aging regime. Lipofuscin is a yellow-brown byproduct of metabolism that tends to accumulate in cells with age, granules resulting from lysomal digestion. It is a marker of aging found in many different cells including ganglia, heart, muscle, kidney, adrenal and nerve cells. Brown “liver spots” seen on the hands and faces of aged people are lipofuscin deposits. While lipofuscin is not toxic, accumulations of it can impair normal cell functioning. These accumulations can be thought of as piles of uncollected garbage clogging up the insides of cells. Lipofuscin deposits, like AGEs, are not wanted. Lipofuscin accumulation is particularly a problem in post-mitotic (non-dividing) cells, such as most nerve. brain and muscle cells and cardiac myocytes. Accumulation in brain cells appears to be an important issue connected with heavy consumption of alcohol. Hearts with heavy accumulations of lipofuscin may appear to be black when surgery is performed on them.

Lipofuscin accumulation is implicated as a major risk factor in a number of age-related disease processes including macular degeneration and vision loss, Alzheimer's, Batten and Parkinson diseases, melanosis coli, denervation atrophy and chronic obstructive pulmonary disease, to name a few.

Readers who wish to learn more about this theory can view my June 27 2009 blog post that greatly expands on the above information and cites multiple research references: Research Roundup on the Lipofuscin Theory of Aging.

To the Lipofuscin Accumulation Firewall

6. Chronic or Excess Inflammation

Excess or chronic inflammation appears to be a core condition underlying many if not most age-related disease processes Inflammation is a natural process, the response of circulatory system tissues to stimuli perceived to be harmful, such as, damaged cells, irritants or infectious pathogens. Inflammation is an automatic approach to eliminating injurious stimuli and to starting healing - a protective attempt by the body to remove the injurious stimuli as well as initiate the healing process for the tissue. Excessive or chronic inflammation, on the other hand, is an inappropriate response that can lead to all kinds of damage including potentially fatal conditions. It can be initiated by multiple inter-cellular signaling pathways and may be due to multiple causes including oxidative damage and the presence of AGEs as mentioned above.

In a condition of chronic inflammation there is a continuing release of pro-inflammatory signaling molecules including autocoids and cytokines. The impressive list of inflammatory disorders includes congestive heart disease, stroke, rheumatoid arthritis, chronic inflammation, tendonitis, pelvic inflammatory disease, vasculitis, auto immune diseases, asthma, other allergies, inflammatory bowel disease, and glomerulonephritis. It is also the active element in acute appendicitis, acute dermatitis, and acute meningitis. Inflammation contributes to the growth of many cancers affecting the micro environment around tumors. It can contributes to tumor proliferation, survival and migration. Many cancer cells secrete substances that promote inflammation, called selectins and chemokines, to contribute to their capability to grow, penetrate surrounding tissues and metastasize. Chronic inflammation such as connected with arthritis can affect joints and lead to orthopedic joint degeneration.

To the Chronic or Excess Inflammation Firewall

7. Immune System Compromise

Immune systems tend to weaken with age – often to the point where common diseases become fatal. Immune system compromise may result from a hereditary condition (such as inheriting genes for lupus or rheumatoid arthritis), from a disease process such as AIDS, or simply from normal aging. Changes in hormones and hormone-like substances may contribute to immune system weakening with age. The production of important hormones that impact on immune system functioning like melatonin, DHEA and HGH decreases with age. In older adults, important immune cells may be inhibited from doing their jobs by an increase in certain prostaglandins that tend to regulate important body processes such as body temperature and metabolism. In elderly adults infection-fighting cells (lymphocytes) mobilized in response to an infection are likely to be less responsive and less effective than those found in younger adults. In aged people compared to younger ones, fewer antibodies are produced, they are less vigorous and the duration of their response is shorter. So, the immune system of an older adults -- including lymphocytes and other types of cells -- typically reacts more slowly and weakly.

I have already mentioned how tissue glycation can contribute to immune system disfunction, and how tissue glycation is correlated with oxidative damage and inflammation - another example of the multiple cross-links between the theories of aging.

The bottom line is that older people become more susceptible to infectious diseases with age. A viral infection or pneumonia infection that a young person could shake off in a week might kill his great-grandparent in a nursing home. Also, susceptibility to auto-immune diseases like fibromyalgia, lupus, scleroderma and arthritis increases with age. Old folks in their 70s and beyond are more likely to produce autoantibodies which attack parts of the body itself instead of infections. These autoantibodies contribute to causing atherosclerosis, rheumatoid arthritis and other pathological conditions.

Autoimmune diseases like rheumatoid arthritis and Lupus often co-exist with certain cancers. I have written a series of three blog postings on Autoimmune diseases and lymphoma: Part I: focus on Lupus, Part II: focus on inflammation, and Part III: focus on lymphomas. Other blog entries relevant to immune systems functioning include Immunosenescence - No thanks for the memories.

To the Immune System Compromise Firewall

8. Neurological Degeneration

Neurological degeneration can take many forms which become increasingly manifest with age. It is often closely related to immune system compromise, decline in hormone levels and other already-conditions which tend to compromise nerve cells and tissues. I have already mentioned Alzheimer’s disease, Parkinson’s disease and macular degeneration as examples of age-related neurological diseases. All forms of memory loss and senile dementia fall in this category as well as increased stimulus response times which can make driving and even walking dangerous. Degeneration of neuron systems in the inner ear can make it difficult for older people to maintain their balance. They frequently fall and hurt themselves. Orthopedic injuries associated with falling constitute one of the major maladies of the aged leading to loss of normal functionality and nursing home occupancy.

The nervous system consists of much more than interlinked neurons. Glial cells like Schwann cells and oligodenadrocytes manufacture myelin, an insulating substance, and wraps it around the axons connecting neurons. Astrocytes are other glial cells that regulate the wrapping process. It is thought that health and longevity of those cells is as important as that of neurons for mental health maintenance. Multiple sclerosis and cerebral palsy, for example are known to be diseases associated with malfunctioning glial cells. And improper myelin formation possibly contributes to several other mental illnesses such as autism, schizophrenoa and bipolar disease. The blog entry Spinal cord injury pain - a personal story and a new paradigm deals with the key roles of microglia in chronic neuropathic pain. The blog post New views of Alzheimer's disease and new approaches to treating it describes how senesence of microglia may be a root cause of Alzheimer's dementia. The blog post BDNF gene - personality, mental balance, dementia, aging and epigenomic imprinting relates to the importance of healthy functioning of the BDNF (brain derived neurotrophic factor) gene for maintaining mental balance and averting dementia. Other blog posts related to Alzheimer's disease include Alzheimers disease studies validate anti-aging firewalls suggestions, Alzheimer's Disease research update, The social cost of Alzheimer's disease and late-life dementia, and a short post Deconstructing Alzheimer's Disease - role of mitochondria.

Increasing research evidence suggests that maintaining a sufficient and consistent rate of neurogenesis in the brain, particularly in the hippocampus, is important for the maintenance of cognitive health. Insufficient or irregular neurogenesis is thought to be a causative factor in bipolar disease and other mood disorders. Neurogenesis takes place throughout the life of a mammal in two major brain structures: the dentate gyrus of the hippocampus and the subventricular zone of the forebrain. In these regions neural progenitor cells continuously divide and give birth to new neurons and glial cells. In the mammalian brain neural progenitor cells are multipotent. They can differentiate into neurons, astrocytes or oligodendrocytes, though the factors that determine differentiation are poorly understood. The rate of neurogenesis tends to decline with advancing age in old mammals, as well as the does the number of functional neurons.

Hippocampal neurogenesis is affected by environmental factors, body stress factors like radiation, integrity of circadian gene expression, emotional states and hormonal signals. Further, neurogenesis is tied to circadian rhythms and time-of-day dependent. Neurogenesis is positively affected by learning, voluntary exercise, good physical environment, regular daily rhythms and by ingesting certain mood-stabilizing agents including lithium and, fluoxetine (Prozac). It is negatively affected by involuntary stress, radiation, toxicity and several types of chemotherapy. An oxidative environment inhibits neurogenes while an antioxidant-rich environment promotes it. Also, an oxidative environment favors the production of astrocytes over the production of neurons. (ref). How all these factors interact is a matter of continuing exploration.

A number of substances in the combined anti-aging firewall promote neurogenesis, as described in the Firewall Section for the Neurological Degeneration theory of aging.

The cell-cycle of neurogenesis appears to be tied to daily light-related circadian cycles, with neural progenitor cells entering the cell cycle continually, but passing through into the M phase and generating new neurons mainly at night (at least in rats). It is speculated that irregularities in daily cycles and disrupted sleep may interfere with neurogenesis resulting in mood swings and possibly bipolar events. It is interesting that taking mood stabilizers like fluoxetine may not only inhibit serotonin uptake but also result in accelerated neurogenesis.

Researchers are actively exploring the genetic and cell-biology bases of neurogenesis. It appears that the Bcl-2 gene functions to regulate development and survival of neurons in the central nervous system and is very important for neurogenesis. Also, it appears that expression of a cell nuclear factor, NF-kappaB, is important for neurogenesis. A discussion of the relationship of NF-kappaB to neurogenesis is included later in this paper. Unfortunately there is a paradox in that the same mechanisms that promote neurogenesis, like expression of Bcl-2 and NF-kappaB, can also promote carcinogenesis(ref). The Ink4a proteins which are increaingly active with age suppress those mechanisms leading to increased protection against cancers with age, but at the cost of decreased neurogenesis and decreased proliferation of other somatic stem cell types. Sorting out the differences between the biomolecular programs that promote stem cell expression and the programs that promote cancers, assuming there are some differences, is a major challenge that must be overcome if substantial life extension is to be made possible.

The interdependence of these theories of aging should be becoming clear at this point. Neurological degeneration could be triggered by oxidative damage, lipofuscin accumulation, inflammation, faulty mitochondrial signaling or defects in energy production for example. And problems could originate in neurons, glial cells or in their association. The production of new neurons from neural stem and progenitor cells is important, and the cell-cycle factor NF-kappaB enters criticaly into the picture. Finally, there is an issue of how to promote neurogenesis without encouraging the formation of cancers.

To the Neurological Degeneration Firewall

9. Declines in Hormone Levels

Many affects of aging are related to declines in hormone levels with age and the resulting negative impacts on immune system functioning. The declines appear to start around age 20 and affect just about every major hormone including Human Growth Hormone (HGH), DHEA, pregnenalone, testosterone and melatonin. Typically HGH declines about 80% from age 20 to 60. Some researchers have suggested that these declines constitute a major cause of aging.

As the hormones run down, so do all of the body systems which they regulate. Many body systems are re-regulated or affected by declining hormone levels including the immune system as already mentioned. The transcription of many genes is affected by the changing hormone mix. Impacts are thought to exist in many spheres including energy level, metabolism and weight, endurance, sexual drive, mental acuity, ability to sleep, age-related bone loss, and disease resistance. Specific diseases are associated with various hormone deficiencies. For example, incidences of testicular cancer and exotic-sounding diseases like cryptorchidism and hypospadias appear to be correlated with testosterone deficiency. Hormone levels appear to cause changes in male and female characteristics with age. Also, certain prostaglandins, hormone-like acids that affect important body processes such as body temperature and metabolism, tend to increase in old age and inhibit important immune cells from doing their jobs. Older adults appear to be more sensitive to the action of prostaglandins than younger adults. And some researchers think this could be a major cause of immune deficiency in elderly people.

Decline in bone density and osteoporosis are also attributable to shifts in hormone levels with age. Inadequate bone growth and mineral density is responsible for many older people sustaining serious injuries from falls, losing their capabilities to move freely, or even to walk.

Along with declines in levels of critical hormones, insulin resistance is another frequent hormone-related hallmark of aging, leading to hyperinsulinemia. Hyperinsulinemia shows up as a major risk factor for many age-related diseases, including cardiovascular diseases, Alzheimer's disease, and stroke.

To the Declines in Hormone Levels Firewall

10 Susceptibility to Cancers

While not properly a causal theory of aging, the danger of cancer pathology increases radically with aging and is the second major cause of age-associated mortality. Cancer is therefore worth separate treatment in this essay and cancers requires their own firewall for longevity. Age-related susceptibility to cancers is associated with multiple genetic changes in tissues probably due to causes basic to the other theories of aging already mentioned. There are many different cancers each with their individual properties but all come about through a combination of genetic changes. Genes related to cell differentiation, proliferation, apoptosis and angiogenesis can affect ability of cancers to come about, survive and grow. A tissue becoming cancerous may entail simultaneous mutation, activation or inhibition of hundreds of genes. Cancers may be initiated due to oxidative DNA or mitochondrial DNA damage or cell senescence. Inflammation both supports cancer growth and is often caused by it. And a healthy immune system, one that detects and wipes out cancer cells, is key to defense against many kinds of cancers.

The genetic pathways associated with the various kinds of cancer are much more complex than previously thought. They are the subject of much research throughout the world and are slowly being decoded. As this happens science is replacing trial-and-error and in coming decades we can expect to see constantly improved cancer treatments going beyond the traditional brute-force ones: surgery, burning with radiation, and poisoning with chemotherapy. Already, these treatments are being augmented by new science-based approaches. Tumor angiogenesis (blood vessel proliferation) inhibition is an approach only available in the last two years, yet it is already in widespread use. Tumor telomerase inhibition is among other research-based approaches that are likely to become available soon. Among the blog entries relating to new insights about cancers or new treatments for them are DNA demethylation - a new way of coming at cancers, Trojan-horse stem cells might offer an important new cancer therapy, On the TRAIL of a selective cancer treatment, On cancer stem cells, Update on cancer stem cells, Autoimmune diseases and lymphoma – Part III: focus on lymphomas, Dendritic cell cancer immunotherapy, Cordyceps militaris and cancer, Progress on fighting glioblastoma, Big pharma is targeting cancer stem cells, Nrf2 and cancer chemoprevention by phytochemicals, New-science approaches to detecting, preventing and curing cancers, News on disabling cancer stem cells, The NRG1 Gene - an important new tumor suppressor gene?, Progress in genetically profiling cancers, * Turning P53 on in cancer cells, * Melanoma research update, * Skin Cancer immunotherapies , and * Curcumin, cancer and longevity. For the present, I suspect that it is possible for people without genetic pre-dispositions to cancer or exposed to cancer hazards to construct a quite robust firewall against cancer. I do not expect to experience a serious cancer problem in my life.

To the Susceptibility to Cancers Firewall

11 Susceptibility to Cardiovascular Disease

Cardiovascular diseases are the biggest killers of old people. These comprise a host of maladies including cardiovascular stroke, heart attacks, ischemia (inadequate blood flow), congestive heart disease and atherosclerosis. So again, while cardiovascular diseases are not properly a causal theory of aging, they are worth discussion here. And it is important to create an effective firewall against these diseases. As for cancers, age-related susceptibility to cardiovascular diseases is attributable to multiple causes which are basic to the other theories of aging already mentioned. For example myocardial cell membranes become remodeled with advanced age possibly due to stress and oxidative damage, and this remodeling impacts negatively on mitochondrial function which is critical for sustaining energy production in cardiac membranes. The age-related remodeling appears to involve an imbalance between omega-3 and omega-6 fatty acids in these membranes as well as dysfunctional Ca2+ metabolism. The mechanisms of buildup of arterial plaque are related to over-eating, poor eating, overweight, stress, high blood pressure, conditions such as diabetes, immune fatigue and lack of exercise. Chronic inflammation is at the head of the list, and also implicated are tissue glycation, oxidative stress, declining immune functions, and changes in hormone levels. Insulin resistance is also highly implicated in the creation of heart disease risk as well, of course, in diabetes. A vicious cycle ensues for people who are genetically susceptible to insulin resistance when they eat a high glycemic-index diet and are sedentary. They gain weight and become obese. Insulin resistance worsens with the increase in weight and the result is gaining even more weight making themselves increasingly susceptible to cardiovascular diseases, diabetes and other serious conditions. The biology and molecular dynamics of diabetes are discussed in this blog post.

To the Susceptibility to Cardiovascular Disease Firewall

12 Telomere Shortening and Damage

The Queen of existing theories of aging is that most of the diseases of old age come about through cell senescence due to telomere loss. Telomeres are the “caps” found on the end of chromosomes in somatic cells. They consist of long repeated strings of what appears to be otherwise inert DNA, much like the ends of shoelaces. Telomeres do not encode genetic information. Their role is to preserve the integrity of the information encoded in chromosomes during the process of cell division. When a cell divides, enzymes that duplicate the chromosome and its DNA can only produce a slightly shorter chromosome, with a little missing from each end. The telomeres become a bit shorter in the daughter cells but this does not matter because all genetic information is preserved. This works for a large number of cell replications – perhaps 50 or 70 – but after that point the telomeres are too short for reliable chromosome duplication. And at that point reliable cell duplication is no longer insured. It has long been known that a culture of somatic cells will live through a certain number of cell divisions and then reach the “Hayflick limit” and die. The telomere theory explains why this is so.

Telomere shortening can be observed in mitotic (dividing) human cells during aging. Further, almost all chronic diseases increase the rate of cell turnover and therefore telomere shortening. In body organs, cells with depleted telomeres may settle into bad-neighbor senescence sending out noxious signals to their neighbors, commit apoptosis, or reproduce with genetic errors in the chromosomes. Cancers and other pathological situations can result. It appears that cellular senescence initiates a self-amplifying cycle between mitochondrial and telomeric DNA damage. The telomere shortening theory of aging suggests that when a substantial number of cells in an organ approach the Hayflick limit and cell senescence, integrity of that organ can no longer be assured and that virtually all of the conditions and diseases of old age are thus traceable to cell senescence. Telomeres are the “clocks” that determine life spans in humans according to this theory. There is much experimental evidence related to telomere lengths and their significance.

Cell senescence explains why the diseases of old age become so extreme with old age. As the clocks start to run out there is a mounting tide of problems and diseases and it appears that there is an age limit of about 120 years that is insurmountable unless a way can be found to extend telomeres or keep them long. The research evidence implicating telomere shortening in the degenerative diseases of aging continues to build up (ref) (ref) and is no longer questioned.

There are tests that can measure telomere lengths, and average telomere length is often used to estimate biological age and remaining life span of an organism. It is known that individuals exposed to disease or oxidative stress have significantly shorter average telomere lengths than control groups. Minimization of stress, good rest, good diet and good mental attitude can result in longer average telomere lengths. So can regularly taking antioxidants and viatamins. Experienced stress of all kinds tend to reduce telomere lengths. A bout of radiation therapy or chemotherapy can significantly reduce average telomere length. A recent study measured telomere lengths of long-term family care givers, people who attend to chronically sick children, and compared these to telomere lengths of non-caregivers of comparable ages. The care givers had shorter telomeres and appeared to be biologically 4-5 years older than the non-caregivers. One recent study indicates that a history of childhood emotional trauma such as having been beaten or sexually abused is stongly correlated with shorter telomere lengths in grown adults(ref). Telomere length is often used as a surrogate in laboratory experiments to assess the impact of experimental biochemical processes on life spans.

A November 2009 Blog entry describes a breakthrough telomere research finding linking telomere shortening to another of the key theories of aging, Programmed Epigenomic Changes. "Telomeric shortening at some point induces DNA damage which lets loose signaling which changes the epigenome disrupting epigenetic silencing and resulting in pro-aging global DNA expression."

There is more to the the theory since germ-line cells and most cancer cells seem to be able to reproduce indefinitely. Their telomeres do not get shorter with reproduction. In 1980, two women researchers, Elizabeth Blackburn and Joan Steitz, discovered that cells contain a gene for a substance called telomerase that can paste telomere ends back on again after cell division. If telomerase is added to a human cell culture in a lab, it can reproduce indefinitely. When the telomerase gene is activated in a germ or cancer cell line, that cell line becomes essentially immortal.  Dolly, the first cloned sheep, died prematurely from old age because the telomeres in the cells used to make the clone were already short because they came from a mature sheep.

In the caregiver stress study, the level of telomerase activity was significantly less in the higher-stressed group(ref). There seems to be a strong positive correlation between high levels of stress hormones and free-radical damage, and both of these correlate negatively with level of telomerase expression. Also interestingly, in an experiment when volunteers with high levels and low levels of telomerase expression were subjected to psychological stress, measurable cardiovascular reactions such as heart rate and pulse pressure were significantly milder in the high-telomerase-expression group(ref). So, the relationship between experienced stress and low level of telomerase expression appears to be a two-way street.

One explanation for the decline in immune function with old age is cell senescence – immune cells dying or losing functional capacity because they have duplicated too many times. The same result occurs when immune system cells duplicate at a high rate to fight infections. At one time it was fashionable to talk about an immune system becoming “worn out” because of too many challenges to it due to sickness or age. Now it is more fashionable to say that the immune system T cells telomeres are too short.

Research reported by Rita Effros of UCLA and her colleagues(ref) indicates that cortisol inhibits the expression of telomerase in immune system cells, This explains why people subject to considerable stress tend to have shorter telomeres. Of course, cortisol is produced in the body in response to stress.

A therapy that enhanced expression of telomerase in immune system CD4 and CD8 cells could offer many health and longevity benefits by delaying or preventing senescence of these cells. Benefits could include less bone loss, avoidance of release of inflammatory cytokines, maintenance of strong anti-viral capability, better capability of dealing with stress, and prevention of HIV infections resulting in AIDS. A collection of studies co-authored by Rita Effros relating cell senescence to HIV pathology can be found here.

One benefit of enhancing telomerase expression in immune cells could be for patients with systemic lupus erythematosus (SLE). Many T cells divide continuously in patients with SLE, Although the natural level of expression of telomerase in CD4(+) and CD8(+) cells is high in SLE patients, it is still insufficient to prevent telomere shortening in these cells. Prevention of this shortening by telomerase activation could prevent premature senescence of these cells, and could possibly prevent some of the pathological consequences of SLE.

It is interesting that all of the major risk factors associated with cardiovascular disease (obesity, smoking, poor lipid profile, high blood pressure, diabetes and psychological stress) are associated with key markers of cellular aging (shorter telomere lengths, reduced telomerase activity and higher oxidative index)(ref). So the Telomere Shortening theory of aging impacts directly on the Suceptibility to Cardiovascular Disease theory.

In patients infected with HIV there is typically an initial period of several years during which the immune system is capable of controlling the disease before it finally breaks out into being full AIDS. There is evidence that during this period CD4 and CD8 cells reproduce at an abnormally high rate to keep up their battle with the infection. When these cell lines approach senescence and can no longer reliably reproduce because their telomeres are too short, they can no longer control the spread of the HIV virus and full AIDS finally breaks out. It is thought that enhanced activation of telomerase in these immune cells could make them essentially immortal and continuously capable of fighting off AIDS. Research progress towards this objective was reported recently by a UCLA/Geron team headed by Dr. Effros(ref). "The present study shows that exposure of CD8(+) T lymphocytes from HIV-infected human donors to a small molecule telomerase activator (TAT2) modestly retards telomere shortening, increases proliferative potential, and, importantly, enhances cytokine/chemokine production and antiviral activity." Study of the Geron patent and literature references indicate that TAT-2 is cycloastragenol, a substance that can be derived through purification of astragaloside IV, itself a component of astragalus root. ""In this study, we demonstrate that TAT2 can transiently activate telomerase, slow telomere loss, increase replicative capacity, and, importantly, enhance immune function in CD8+ T lymphocytes from HIV-1-infected persons. These data suggest a possible novel immune-based strategy to complement current treatments, which are primarily directed at the virus(ref)."

An evolving perspective on the Telomere shortening theory of aging (last updated January 24 2010)

Twelve years ago, if I were asked about the prospectus for radical life extension to well beyond 110-120 years of age I would have bet most of my chips on telomerase. I would have responded that such life extension will likely depend on our discovering ways to keep the telomeres in our somatic cells from getting to be too short. This would prevent replicative cell senescence and avert the consequent ravages of old age.

Now, based on what is being discovered and given that I am personally pursuing an initial approach to keeping my telomeres long, I see this Telomere shortening theory of aging in a much more nuanced perspective. Essentially everything I have written above still remains valid. But there are several additional factors to take into account:

• I continue to believe that telomere length and expression of telomerase are extremely relevant to longevity. Going back to a 2003 study "We aimed to assess an association between telomere length and mortality in 143 normal unrelated individuals over the age of 60 years. Those with shorter telomeres in blood DNA had poorer survival, attributable in part to a 3·18-fold higher mortality rate from heart disease (95% CI 1·36–7·45, p=0·0079), and an 8·54-fold higher mortality rate from infectious disease (1·52–47·9, p=0·015). These results lend support to the hypothesis that telomere shortening in human beings contributes to mortality in many age-related diseases(ref) ." Also, telomere lengths in older people are predicitive of mortality. Several additional research studies confirm these findings.
• I also continue to believe that telomerase activation may contribute significantly to longevity, if by no other action than through prevention of age-related diseases. "While human cells dividing in culture lose telomeric DNA and undergo changes that mirror certain age- or disease-associated changes in vivo, telomerase transduced cells have extended replicative capacities, increased resistance to stress, improved functional activities in vitro and in vivo, and no loss of differentiation capacity or growth control. In addition, telomerase transduction in vivo can prevent telomere dysfunction and cirrhotic changes in liver of telomerase knockout mice. Thus, pharmacological activation of telomerase has significant potential for the treatment of a broad spectrum of chronic or degenerative diseases (ref). "
• Telomere length stabilization or lengthening is a very complex process and can take place either through expression of telomerase or through an independent ALT process manifest in some cancers(ref). Telomerase consists of a number of proteins with different enzyme binding characteristics. The three-dimensional structures of telomere binding proteins are very important. (See the note 9/15/08 on telomere binding proteins). The process of telomerase acting to lengthen telomeres has a complex internal microstructure. “Unlike pontin and reptin, TCAB1 is a true component of telomerase. But it’s not required for the enzyme’s activity. Rather, it recruits the telomerase complex to processing and holding areas in the nucleus of the cell called Cajal (pronounced “cuh-hall”) bodies. Like a high-end garage, Cajal bodies apply the finishing touches to a variety of proteins that use small molecules of RNA to conduct their activities (telomerase, for example, uses an RNA molecule as a template for the DNA chain it tacks onto the ends of chromosomes). When appropriate, TCAB1 then chauffeurs the telomerase complex to the waiting end of a newly replicated chromosome. (ref)” This process can be mediated in a number of ways, both by internal cell signaling pathways and by external stimulation or inhibition. Replicative senescence of cells seems to have to do with telomere structure as well as length(ref), Telomere lengthening is not just a simple matter of turning telomerase on or off as once thought(ref).
• The telomere-binding proteins which regulate the enlongation process leads the expression of telomerase to act so that the shortest telomeres are enlongated the most(ref)(ref). This is interesting because it appears that the specific group of chromosomes with the shortest telomeres rather than either all or only one or two sentinel telomeres is responsible for the induction of replicative senescence(ref). In other words, telomerase appears to lengthen telomeres selectively so as to reduce the probability of replicative cell senescence.
• The “Hayflick limit” of approximately 50 cell divisions before cell senescence sets in is a very rough approximation and can vary significantly by cell type and probably according to circumstances. Some stem cells may divide over 1,000 times before evidence of senescence. It appears that there is much more natural telomerase expression than once thought, especially in stem cells, in dividing progenitor cells in renewing tissues, and “even in dividing myocytes of repairing cardiac muscle. It now seems likely that telomerase is active in vivo where and when it is needed to maintain tissue integrity.(ref)”
• Indicative of the complexity involved, recent research indicates that telomerase plays several other important roles besides that of extending telomeres. Telomerase expression is involved in critical cell signaling pathways involving DNA repair, regulation of gene expression, and cell apoptosis. Of practical significance from an anti-aging viewpoint, the telomerase protein component TERT can activate the differentiation and proliferation of adult stem cells, and does this in a way independent of telomere lengthening. See the updated discussion in the firewall section for the Deterioration of the Stem Cell Supply Chain theory of aging. It may well be that the ccapability of telomerase to promote the health of and activate the differentiation of adult stem cells is of equal or even of greater importance for longevity than its capability to extend telomeres.
• Despite the impressive body of knowledge about the roles of telomeres and telomerase in the aging process, there is much more to human aging than implied by simply viewing telomere length as the ultimate clock of aging. In non-dividing cells, other factors such as mitochondrial dysfunction, glycation and lipofuscin accumulation may be much more important for cell aging and death than replicative senescence. Mice have very long telomeres and appear to die from mitochondrial failure, cancer or other reasons not directly connected to telomere length.
• There appear to be several other clocks related to aging in addition to telomere length. One is the accumulation of INK4a/P16 as well as NF-kappaB in cells with age. And this directly relates to decline in stem cell differentiation as a function of age (See the discussion for the Deterioration of the Stem Cell Supply Chain theory of aging. Another clock appears to be a systematic change in expression of certain key genes with age(ref). (See the discussion for the Programmed epigenomic changes theory of aging). It is not known whether or how these clocks and the telomere shortening clock are linked ot correlated or whether other clocks are also involved. And it is not known which clock determines the existing human age limit of perhaps 120 years.
• Most telomere-related research today continues to be focused on turning telomerase expression off in cancer cells, not on turning it on in normal cells. Hardly a week goes by without a new press release on cancer telomerase-inhibition research. And these press releases too-frequently refer to telomerase only as an evil substance that makes cancer cells immortal and that needs to be stamped out. This is unfortunate given that telomerase expression is probably critical for preserving telomere lengths and therefore for preventing cancers in the first place, and that telomerase expression is critical for replacement of body cells through promoting differentiation of somatic stem cells.
• The telomere shortening clock is less inexorable than once thought. As recently (Feb09) discussed in the companion Blog to this document, a report(ref) on a Swedish study of changes in telomere lengths in 959 individuals who had contributed blood samples at 9- to 11-year intervals reveals several interesting findings:
• Telomere shortening with age varies significantly between individuals. Telomere length at a certain age may not be as good a predictor of future lifespan as previously thought. Also, it is not necessarily a good predictor of susceptibility to cancers(ref).
• In general, the rate of telomere shortening appears to depend on the telomeres’ original length. People starting out with the longest telomeres experienced the fastest rate of telomere shortening and vice versa.
• In some individuals, the telomeres measured actually got longer with time. In roughly a third of the subjects, the telomeres actually lengthened over the study period.

The January 2010 blog post Vitamins, supplements and telomerase - upregulation or downregulation? points to a different study in which telomere lengthening was observed over a long period of time for a sizeable portion of the population studied. Also, it appears that taking a number of popular supplements in the anti-aging firewalls supplement regimen like Vitamin E, fish oils, Vitamin D3 and resveratrol can lead to telomeres being longer than they otherwise might be, possibly because they induce the production of telomerase, possibly for other reasons. And, several of these supplements actually turn off telomerase in cancer cells.

These results suggests to me that telomere shortening is a complex process involving a balance of shortening due to cell division, lengthening due to natural telomerase expression and perhaps cell replacement due to differentiation of stem cells. And these in turn are affected by many lifestyle and dietary factors and moderated by cell-signaling feedback loops.

My current bottom-line with respect to the Telomere-shortening theory of aging is:

• Telomere length stabilization and controlled telomerase activation are both very important for prevention of diseases related to cell senescence and maintaining human health.
• Strategies to keep telomeres from shortening such as those listed in the firewall section for this aging theory may in fact work.
• Expression of telomerase is important for other reasons beyond stabilizing telomere lengths, including the activation of stem cell differentiation.
• Because of the key role of telomerase activation in oncogenesis, it is important to approach telomerase activation with caution. In particular, I have had a concern that use of telomerase activators may promote the differentiation of cancer stem cells leading to rapid cancer growth. This concern lessened consideribly when I recently earned of research saying that for one cancer stem cell line, telomerase activation decreased rather than increased cell differentiation(ref).
• Telomere length stabilization and controlled telomerase expression may be necessary for achievement of extraordinary longevity, but by themselves may not be sufficient to assure it.

An interesting lecture presentation on telomeres and telomerase by Professor Elizabeth Blackburn, one of the co-discoverers of telomerase, can be viewed by clicking here.

To the Telomere Shortening and Damage Firewall

13 Programmed Epigenomic Changes

In its most basic form this theory holds that aging is not just the result of accumulation of damage, as many of the aforementioned theories do, but is the result of some kind of program that unfolds through life from conception to death. This is a relatively old theory, but one with strong new supporting evidence. A classical argument for this theory is based on the theory of evolution. It holds that survival of a species requires individual survival only long enough for reproduction and care of offspring until they achieve independence. Young vital individuals are best suited for survival, and older members of the species are best gotten rid of. They should be put out of the way when their turn comes so that they do not compete with younger members of the species for resources. Therefore, the argument goes, evolution would set it up so that older individuals surely die off at a certain point, not just by accumulation of accidental damage but also by a programmed mechanism that is guaranteed to clear the deck. For a long time the concept stopped with this idea. There was no biological evidence of a process of programmed aging, so the theory remained as just an academic possibility. Genetics research empowered by gene chips and computational genetics are now starting to produce such evidence.

In the last two or three years, genetics research, particularly computational genetics, has been revealing the possible existence of complex additional genetic switching mechanisms that could contribute to or be part of an overall program of aging. The emerging concept is that hundreds of genes are involved in what we call aging, and that there is one or several master programs according to which these genes are switched on and off through a lifetime in an intricate pattern to produce early growth, maturation and, finally, assured death.

Epigenomics provides a general framework for explaining aging as a programmed phenomenon. Epigenetics is concerned with both heritable and non-heritable changes in gene expression and activity and also stable, long-term alterations in the gene transcriptional potential of a cell. Epigenetic information is based on the experience of a cell, is stored via DNA methylation and histone actylation patterns, may be passed on in the process of cell division, and may be accumulated over the lifetimes of a cell and all of its ancestors. While epigenetics refers to the study of single genes or sets of genes, epigenomics refers to more global analyses of epigenetic changes across the entire genome. So, the epigenomic profile of an organism changes continuously over the lifetime of that organism and that set of changes defines what we call aging. I outline three current chains of research that partially support the idea of programmed genetic changes of aging leading to death.

a. Telomere shortening and damage

The first possible mechanism of programmed aging to come along in the 1990s was the telomere shortening theory already treated above (the 12th theory of aging). The genetic program in this case is simple: telomeres in somatic cells become shorter each time the cell divides until the point where genomic instability and cell senescence sets in. I will discuss two additional llines of research related to programmed epigenomic changes: b) changes in DNA methylation and histone acetylation, and c) changes in expression of a key cell nuclear factor NF-kappaB . Prior to revision of this discussion on May 7 2010, b) was listed as a separate candidate theory of aging.

b. Epigenomic changes in DNA methylation and histone actetylation

(This description is adopted from the blog posting DNA methylation, personalized medicine and longevity )

According to this theory of longevity, an important mechanism is DNA methylation,  a process by means of which sites adjacent to genes on chromosomes (promoter regions) are chemically methylated after a cycle of DNA replication(ref).  The methylation is passed on in the course of cell divisions and through generations of people.  The methylation pattern captures the ancesteral history of the cell that is not in the genes themselves and is unique to every cell.  DNA methylation is thought to be one of the main ways epigenetic information is captured and passed on.   Histone acetylation, another important mechanism of epigenomic change, relates to folding of histones, the protein spindles around which DNA is wrapped. Patterns of histone acetylation are also part of epigenomic memory. See the blog post Epigenetics, Epigenomics and Aging.

The DNA methylation profiles of individuals are unique, change with aging, and include valuable clues to disease and treatment progress.  For example, DNA methylation of tumor suppressor genes predicts the relapse risk in acute myeloid leukemia for patients in clinical remission(ref).   So, research groups throughout the world are building databases of DNA methylation epigenomic information, in part to establish methylation markers that are “normal” and other markers that indicate diseases, susceptibility to particular disease conditions and associated information . See the blog entry Epigenetics, Epigenomics and Aging.

DNA methylation is impacted by aging and impacts on aging(ref).  The suggested theory of human aging here is that DNA methylation and histone actylation patterns in cells define the biological age of an organism. They tell the body how old we are and drive the symptoms and signs of aging.

Methylation in the promoter region of genes is thought generally to be associated with gene silencing.  Longevity-related and health-promoting genes may be turned off in the process of aging due to progressive methylation.  The P66Shc gene for example, associated with longevity in mammals, appears to be silenced through some combination of histone deactylation (resulting in protein folding) and cytosine methylation(ref).  Little is known yet about how to go about DNA demethylation, but demethylation appears to be necessary for epigenetic cell reprogramming(ref).  The intriguing possibility is that through selective demethylation of aging markers it might some day become possible to restore cells, organs and organisms to earler age states. As of now relatively little is known yet about how DNA methylation plays out in aging, yet alone how to work with DNA demethylation in order to stop or reverse aging.  Again, it appears that the more we discover, the more there is that we know we don’t know.

c. Increase in aberrant NF-kappaB signaling

An important line of epigenomic research relates to NF-kappaB signaling. NF-kappaB is a nuclear transcription factor involved in cell signaling, i.e. a protein that binds to a specific sequence of DNA. It is present in a latent (non-activated) form in many cell types. On the one hand, expression of NF-kB appears to be one of the body’s regulatory means for handling situations of stress, cancer, damage or disease. In eukaryotic cells NF-kB is an important regulator of genes that control cell proliferation and cell survival. NF-kB regulates anti-apoptotic genes that protect healthy cells from cell death and activates the expression of genes that keep cells proliferating. On the other hand, activated NF-kB binding to genes has long been known to play a central role in promoting runaway inflammation and inflammation’s negative consequences. Oxidative damage, the first theory of aging, is strongly implicated. Free radicals initiate changes that unbind NF-kappaB in the cytoplasm of cells, so that it translocates to the cell's nucleus where it binds to the DNA and initiates inflammatory responses. These consequences are characterized under the sixth theory of aging described above. They include promotion of angiogenesis, proliferation, metastasis and invasiveness in cancer tumors, autoimmune diseases, neurodegenerative diseases and contributing to the activation of human immunodeficiency virus (HIV) leading to AIDS.

There appears to be increasing evidence that inhibition of expression of NF-kB could be a key approach for fighting cancers, controlling inflammatory diseases, AIDS, neurodegenerative conditions like Parkinson’s Disease and a number of other significant age-related maladies.

Recent studies position NF-kB even more centrally with respect to longevity. It is likely that NF-kB expression is central to a programmed set of changes which we call aging. One study(ref1) confirms that that in multiple mammalian tissues (including skin fibroblasts, kidney, cortex, kidney medulla, abdominal muscle, skeletal muscle, and brain), aging involves continuing changes in expression of hundreds of genes. And, further, NF-kB signaling appears to be a major regulator of gene expression related to the aging progress. In fact, by inhibiting NF-kB cell signaling the researchers were able to cause the epidermal tissue of old mice to revert to the state of very young mouse tissue, both in observable characteristics and in genetic expression profile. The authors show that NF-kB cell signaling is a meta-factor for determining aging of nine other key cell types as well, and they argue that the results should apply equally to humans and other mammals.

A very recent study(ref) has to do with the role of Tumor Necrosis Factor (TNF) activating the expression of NF-kappaB in Muscle Progenitor Cells (MPC). This study is also relevant to the fourteenth theory of aging, Deterioration of the Stem Cell Supply Chaiin. TNF acts via a number of pathways in a complicated manner, including activation of NF-kappaB, to produce a variety of effects including induction of apoptosis (cell suicide). This apoptosis is useful when cancers are concerned but is also potentially destructive of healthy cells. It appears that in MPC cells at least, TNF-alpha activates NF-kappaB more in older animals than in younger ones. So, TNF activation of NF-kappaB in older animals can lead to apoptotic signaling and death of otherwise-healthy MPC. The problem is thought to be a decline with age of effective cellular mechanisms for keeping NF-kappaB inactive. Fortunately, as listed in the firewall section for this theory, several dietary substances are capable of restraining the expression of NF-kappaB.

Another study reported in January 2009(ref) adds an additional key piece to the puzzle. It appears that the sirtuin protein SIRT6 is important in limiting the expression of NF-kappaB and thereby restraining aging. The sirtuins are known to be implicated in longevity, but most emphasis so far has been on SIRT1 which is stimulated by resveratrol.

These and related recent studies are important in that they suggest that aging is programmed rather than the result of accumulated damage, and that the program can potentially be reversed.

To the Programmed Epigenomic Changes Firewall

14 Stem Cell Supply Chain Breakdown

This theory holds that aging is due in large or major part to a breakdown in the healthy functioning of the stem cell supply chain. This breakdown may be due to problems in replication or differentiation of critical stem cell populations, depletions of such populations due to aging or pathological conditions, or age-related shutdown of key parts of the supply chain. This theory includes and is more general than and the former 14th theory of aging, Decline in Adult Stem Cell Differentiation. This expanded treatment is more comprehensive and details additional ways in which the stem cell supply chain can be implicated in aging.

This discussion represents a major evolution in my thinking and much of the new material is adopted from blog entries I have generated in the last nine months. It is significantly different than the other aging theories in another respect. This theory represents an original synthesis while the other 13 theories are largely characterized in the existing literature. Stem cell research is churning along at a ferocious rate and is revealing new discoveries almost daily. Therefore this discussion should be viewed as a work-in-progress subject to continuing refinement as more is learned.

The stem cell supply chain

To begin, I characterize the stem cell supply chain and recapitulate some key facts known about stem cells. In a simplified model, think of the 210 kinds of cells found in the human body as falling in five categories:

A. Pluripotent cells, ones which are and capable of differentiating into any other cells. Human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs) are in this category,

B. Relatively undifferentiated multipotent somatic stem cells, such as may exist in bone marrow or vascular walls (e.g. hematopoietic stem cells, mesenchymal stem cells and pericytes).  These multipotent cells are each capable of differentiating into a variety of kinds of somatic cells.

C. More differentiated stem and progenitor cells (e.g. endothelial progenitor cells, myoblasts or satellite cells in muscle tissue).  These are cells capable of differentiating only into specific somatic cell types.  

D. Normal body somatic cells (e.g.  cardiomyocytes, red blood cells, leukocytes, keratinocytes, melanocytes, and Langerhans cells).

E. Senescent cells, ones which no longer can divide.

The list is in order of increasing cell-type specificity and decreasing potency to differentiate into other cell types.  Starting at conception and throughout life, all cells on this list except the senescent ones will selectively reproduce and possibly differentiate into cells of types further down in the list.  In some cell lines there are actually many more intermediate forms of progenitor cells, but a model of five categories of cells is sufficient for this discussion.

Of course all the cells in an individual have the same genome but their DNA acquires additional epigenomic markers as they differentiate.  So, looked at in terms of DNA, the differences between these kinds of cells is one of epigenomics, e.g. DNA methylation, histone acetylation and binding-site molecular folding.

Cells in all categories except Type E can divide to make new cells.  They are all subject to mutation, cell damage, oncogenesis and, it is thought, are subject to replicative senescence due to telomere attrition.  Cells of Type A in the early embryo progressively differentiate to make all cells of Types B, C or D. All cells of Type D result from differentiation of cells of Type A, B and/or C, possibly via intermediary progenitor and stem cell types. Some cells of Type B may differentiate through several intermediate forms before creating Type D cells.  Hierarchy in differentiation is always preserved under natural conditions, although it may or may not necessarily be the case that intermediate stem cell types are involved depending on the kind of cell.

An early embryo consists of A-Type cells.  This supply-chain process continues through life although in aging there will be more and more cells of Types D and E and fewer and fewer active cells of Types B and C. and virtually no active Type A cells left.  Healthy normal aging is thus a matter or cellular supply chain management.  The body must assure that there are not too many Type E cells around for they create havoc.  Type D cells are the workhorses of day-to-day functioning and the key factors involved are insuring a good supply of them by avoiding damage-related or replicative senescence, taking care of their need for nutrition and a healthy intra-cellular environment, and making sure that damaged or proto-cancerous cells are eliminated through proper apoptosis.  Also, it is important to assure that Type B and C cells are able to differentiate properly to provide a reliable continuing source of replacements for the Type D cells. 

The issues for Types B and C cells include seeing that they are in sufficient supply and health so as to be able to differentiate into Type D cells and making sure that the differentiating option is readily available when needed.  Other issues for Types B and C cells are similar to those for Type D cells - preventing damage-related or replicative senescence, and preventing oncogenesis.  It appears that in aged individuals there are few if an active Type A cells around to replace Type B and C cells as they are lost, a possible major reason for aging.

About stem cells and stem cell niches

Before looking further at anti-aging interventions given this new perspective, I review some of the recent relevant research findings and perspectives. Stem cell research is still at an early stage and proceeding at mighty pace. So, this list represents current views which are likely to evolve and be augmented as the months pass.

· The supply chain mechanisms appears to be operable throughout life. For example, it is known that there are some ways Type A ESCs and iPSCs can be introduced into mature adults so that they eventually differentiate into mature healthy Type D cells. The machinery of A to E is always there although later in life there may be no Type A cells left for the machinery to work with.

· The balance of cell Types is highly dependent on the stage of development of the organism, favoring gradual shift to the more-differentiated cell types further down in the list. A human embryo starts out all Type A cells while an aged individual may have virtually no Type A cells left, depleted stocks of Type B and Type C cells and too many Type E cells.

· Even so, health for older people requires continuing operation of the supply chain at some levels throughout life. If an injury is sustained, mesenchymal stem cells must make new tissue cells. If there is loss of blood, hematopoietic stem cells must make new blood cells. And cells that die of attrition trauma or apoptosis must be replaced by new ones. “Hematopoietic stem cells (HSCs) are responsible for blood cell production throughout the lifetime of an individual(ref),” and the same is true for other Type B and Type C stem cells. A new concept is emerging: that age-related changes in the stem cells in many body organs may be responsible for deterioration and decline in functionality of those organs. As a simple example, new research suggests that gray or white hair is due to age-related depletion of melanocytes which is a direct result of depletion of melanocyte stem-cells(MSCs) which in turn is the result of DNA damage. It has been known for some time that " - hair graying is caused by defective self-maintenance of MSCs(ref)." These stem cells, living in hair follicles, can normally both reproduce making new stem cells and differentiate into mature color-producing melanocytes. The new research based on experimentation with mice suggests that DNA damage to MSCs causes them to stop reproducing and instead terminally differentiate into melanocytes. As the melanocytes in hair follicles die off, there are no new melanocytes to replace them because there are no more MSCs to make them.

· Adult stem cells live in niches - stem cell microenvironments and the health of the stem cells and their ability to reproduce or differentiate both depend upon and condition the states of their niches. The behavior of stem cells can be expected to be very different within and without their niches. “Interaction of HSCs with their particular microenvironments, known as stem cell niches, is critical for maintaining stem cell properties, including self-renewal capability and ability for differentiation into single and multiple lineages. In the niche, the niche cells produce signaling molecules, extracellular matrix, and cell adhesion molecules and regulate stem cell fates(ref).” “Various niche factors act on embryonic stem cells to alter gene expression, and induce their proliferation or differentiation for the development of the fetus. Within the human body, stem cell niches maintain adult stem cells in a quiescent state, but after tissue injury, the surrounding microenvironment actively signals to stem cells to either promote self renewal or differentiation to form new tissues(ref).” For example, “Haematopoietic stem-progenitor cells (HSPCs) reside in the bone marrow niche, where interactions with osteoblasts provide essential cues for their proliferation and survival(ref).” Among the other places where niches of Type B cells can be found are hair follicles (see the blog entry Hair stem cells) and in dental pulp (see the blog entry Dental pulp stem cells).

· Both proliferation and differentiation of Type A, B, and C stem and progenitor cells decreases with aging. This is attributed to properties of aged niches which reduce stem cell regenerative potential.  “Our results reveal that aged differentiated niches dominantly inhibit the expression of Oct4 in hESCs and Myf-5 in activated satellite cells, and reduce proliferation and myogenic differentiation of both embryonic and tissue-specific adult stem cells (ASCs). Therefore, despite their general neoorganogenesis potential, the ability of hESCs, and the more differentiated myogenic ASCs to contribute to tissue repair in the old will be greatly restricted due to the conserved inhibitory influence of aged differentiated niches(ref).”  In other words, the very existence of differentiated cells in their niches acts to inhibit the proliferation and differentiation of stem cells. This appears to be a form of age-related epigenomic programming.

· Although the mobilization responsiveness of Type C stem cells declines with age, it appears that their regenerative capability can be restored through environmental messages or induction of Notch activity.  “In adult skeletal muscle, where the resident dedicated stem cells (”satellite cells”) are capable of rapid and highly effective regeneration in response to injury, there is just such a loss of regenerative potential with age. Satellite cell activation and cell fate determination are controlled by the Notch signaling pathway that is initiated by the rapid increase in expression of the Notch ligand, Delta, following injury. In old muscle, this upregulation of Delta is blunted and thus satellite cell activation is markedly diminished. However, by indirectly inducing Notch activity, the regenerative potential of aged satellite cells can be restored.  Furthermore, exposure of aged satellite cells to serum from young mice, either in vivo by heterochronic parabiotic pairings or in vitro, rejuvenates the satellite cell response. This restorative potential suggests that tissue-specific stem cells do not lose their ability to participate in tissue maintenance and repair. Therefore, it may be that even very old stem cells may be capable of maintaining and repairing aged tissues if provided with optimal environmental cues (ref).”

· The gene expression profiles in Type A human embryonic stem cells offer regenerative anti-aging potential not found in more mature stem cells.  “Significantly, this work establishes that hESC-derived factors enhance the regenerative potential of both young and, importantly, aged muscle stem cells in vitro and in vivo (ref).”   This gene expression is driven by age-related epigenomic factors

· Very likely, iPS cells can be induced to do all the jobs done by hES cells. See the March 2009 blog post Rebooting cells and longevity and the June 2009 Update on induced pluripotent stem cells. Finally, there is a relevant July 2009 post on Embryonic Stem cell research news. There is ongoing research progress in generating iPSCs that are free of transfer virus DNA or genetic aberrations. The blog entry Chimeras cites “reports from Chinese researchers of making chimeric mice using induced pluripotent stem cells (iPSCs).”  The mice were made by taking skin cells from mice, reverting these cells to iPSC status where they become virtually identical to embryonic stem cells, and injecting them back into into early-stage mouse embryos.”  “Here we report the generation of several iPS cell lines that are capable of generating viable, fertile live-born progeny by tetraploid complementation(ref).” This work is important in that it established the true pluripotency of the iPSCs used.  If a whole living mouse can be made out of them, they must be capable of differentiating into any mouse tissue.  “The generally accepted “gold standard” for determining whether a mouse iPSC line has been fully reprogrammed is to show that when injected into an early embryo (or blastocyst), the iPSCs can contribute to many different tissues in the resulting chimeric mouse, including the germline(ref). ” Recent reports indicate that mice so-created have reproduced normally and second and third-degeneration descendents of them appear to be normal.

· Other stem cell research reported in July 2007 and indicates that the gene expression profiles of iPSCs and eSCs are different.  The study compared eSCs and iPSCs made by reprogramming skin cells. “The data from the study suggest that embryonic stem cells and the reprogrammed cells, known as induced pluripotent stem (iPS) cells, have overlapping but still distinct gene expression signatures. The differing signatures were evident regardless of where the cell lines were generated, the methods by which they were derived or the species from which they were isolated(ref).”  The researchers do not know what the practical implications of this finding are.  Whatever they are, they seem to be not enough to get in the way of making whole living chimeric mice capable of having children and grandchildren mice. 

· September 2009 news reports development of "a safe strategy for reprogramming cells to a pluripotent state without use of viral vectors or genomic insertions. Their studies reveal that these induced pluripotent stem cells (iPSCs) are very similar to human embryonic stem cells, yet maintain a "transcriptional signature." In essence, these cells retain some memory of the donor cells they once were." -- ""Working with neural stem cells, we discovered that a single factor can be used to re-program a human cell into a pluripotent state, one with the ability to differentiate into any type of cell in the body" said Muotri. Traditionally, a combination of four factors was used to create iPSCs, in a technology using viral vectors – viruses with the potential to affect the transcriptional profile of cells, sometimes inducing cell death or tumors(ref)."

· Being capable of doing everything an embryonic stem cell can do, induced pluripotent stem cells (iPSCs) are likely to be more and more used in future therapeutic applications. They are fully pluripotent, can be made by resetting any normal somatic cell like a skin cell to ground zero state and, unlike cells from other donors, do not invite immune system rejection. Also, newer and faster ways are being discovered to make iPSCs, including generating them wholesale from body fat extracted by liposuction(ref).

· More is being learned about the relationships between stem cells and their niches and environmental messaging relating to stem cell division and differentiation.   For example, “With the expanding knowledge of HSC physiology, a new paradigm emerges in which HSCs and haematopoietic progenitor cells (HPCs) migrate to defined microenvironments within the bone marrow (BM) and to 'activated' or 'inducible' niches elsewhere(ref).” Also you can see ref, and ref. While there is intense ongoing study of the relationships of many kinds of adult stem cells to their niches (Types B and C), the literature reveals little as to whether there are niches of fully pluripotent Type A cells left in mature humans. It is known, however, that embryonic human Type A stem cells form their own niche when in-vitro(ref). 

· Stem cells are subject to replicative senescence, although niche signaling and telomerase expression may have strong influences on their replicative lifespan.  This 2008 study looked at replicative senescence of mesenchymal stem cells in vitro and found it to be “a continuous and organized process.”  “Within 43 to 77 days of cultivation (7 to 12 passages), MSC demonstrated morphological abnormalities, enlargement, attenuated expression of specific surface markers, and ultimately proliferation arrest. Adipogenic differentiation potential decreased whereas the propensity for osteogenic differentiation increased. mRNA expression profiling revealed a consistent pattern of alterations in the global gene expression signature of MSC at different passages. These changes are not restricted to later passages, but are continuously acquired with increasing passages. Genes involved in cell cycle, DNA replication and DNA repair are significantly down-regulated in late passages.”  This form of replicative senescence occurring at each reproduction cycle appears to be absence-of-niche related and not to be driven by telomere shortening, the usual cause of replicative senescence. It highlights the importance of understanding what is going on in stem cell niches. Proliferation and differentiation of stem cells involves a bimolecular dance with their niches.

· A lot is being learned across the whole stem cell spectrum. Several recent research findings related to Type A human embryonic stem cells (hESCs) can be found in my blog post Embryonic Stem cell research news. In particular, this post deals with the relationships among networks of transcription factors, pluripotency and genetic circuits that regulate diferentiation and self-renewal. Again, the point is made that differentiation involves epigenetic markers.

· Highlighting the importance of stem-cell environment signaling, a recent finding is that Co-Culture with Mesenchymal Stromal Cells Increases Proliferation and Maintenance of Hematopoietic Progenitor Cells.  Stem cells seem to be very social animals.

· Buildup of levels of Ink4a/P16 associated with aging slows down the rate of differentiation of adult stem cells.  “Recent evidence shows that loss of Bmi-1, a polycomb transcriptional repressor of theInk4a-Arf locus, results in progressive loss of HSCs in adult mice with subsequent failure of hematopoiesis.” – “ These results show that either both p16Ink4a and p19Arf can inhibit HSC self-renewal in a serial transplant setting, or that only p16Ink4a is necessary(ref).“ I expand on this point later

· Several proteins seem to play key roles in stem cell differentiation, survivin, an apoptosis inhibitor that is a target of cancer therapies, being a key one. “Our studies demonstrate that survivin is essential for steady-state hematopoiesis and survival of the adult, and further, that a high level of survivin expression is critical for proper erythroid differentiation(ref).” Survivin is an example of several factors involved in both stem cell differentiation and the proliferation of cancers(ref).

· This review article looks further at the links between cellular senescence, aging, and bone marrow-derived cells. 

The stem cell supply chain and aging

The operation of the supply chain changes with age and a number of things can happen that accelerate or even define aging. These include:

· Exhaustion of critical pools of healthy adult stem cells

· Slowdown in the rate of operation of the supply chain, e.g. decline in the rate of differentiation of adult stem cells

· Problems in stem cell niches

I touch on each of these.

Exhaustion of critical pools of healthy adult stem cells

Adult stem cells like other cells are subject to mutation, senescence, oncogenesis, damage, apoptosis and other causes of cell loss. Critical pools of stem cells may thus be compromised or lost resulting in loss of their repair, replacement and regenerative functions resulting in multiple symptoms of aging.

Several recent studies have been concerned with how mTOR signaling relates to the fate of an important pool of multipotent stem cells - hematopoietic stem cells (HCSs), the stem cells that give rise to the various blood cell types. Introductions to mTOR signaling and its relationship to longevity can be found in my blog entries Longevity genes, mTOR and lifespan, More mTOR links to aging theories, and Viva mTOR! Caveat mTOR! From an April 2008 publication mTORC1 signaling governs hematopoietic stem cell quiescence: “The stringent regulation of hematopoietic stem cell (HSC) quiescence versus cell cycle progression is essential for the preservation of a pool of long-term self-renewing cells and vital for sustaining an adequate supply of all blood lineages throughout life. Cell growth, the process that is mass increase, serves as a trigger for cell cycle progression and is regulated predominantly by mammalian target of rapamycin complex 1 (mTORC1) signaling. Emerging data from various mice models show deletion of several mTORC1 negative regulators, including PTEN, TSC1, PML and Fbxw7 result in similar HSC phenotypes characterized as HSC hyper-proliferation and subsequent exhaustion, and defective repopulating potential(ref).”  In other words, unless the negative regulators of mTORC1 are working well, the growth factors loosened by mTORC1 will cause the hematopoietic stem cells to reproduce in an uncontrolled manner exhausting the pool of these valuable cells – a major disruption in the stem cell supply chain.  

A second publication highlights the same point. “A balance between quiescence and proliferation of hematopoietic stem cells in interaction with the microenvironment is critical for sustaining long-term hematopoiesis and for protection against stress. — We demonstrated a pivotal role of two downstream effectors of the PI3K/Akt pathway, FoxO3a and mammalian target of rapamycin, as connectors in the SDF-1-/TGF–induced control of the cycling/quiescence switch and proposed a model integrating a dialogue between the two molecules in cell cycle progression(ref).”  Essentially the same point is made by a third study report, the December 2008 publication mTORC1-dependent and -independent regulation of stem cell renewal, differentiation, and mobilization.  “TSC1 exists in a complex with TSC2 and functions primarily as a key negative regulator of mammalian target of rapamycin complex 1 (mTORC1) signaling and protein synthesis — Using hematopoietic stem cells (HSCs) as a model system, we demonstrate that somatic deletion of TSC1 produces striking stem cell and derivative effector cell phenotypes characterized by increased HSC cell cycling, mobilization, marked progressive depletion, defective long-term repopulating potential, and hematopoietic lineage developmental aberrations. On the mechanistic level, we further establish that TSC1 regulation of HSC quiescence and long-term repopulating potential and hematopoietic lineage development is mediated through mTORC1 signaling(ref).”

The bottom line is that effective mTORC1 negative regulation is essential for keeping the stem cell supply chain working well, at least insofar as hematopoietic stem cells are concerned. FOXO transcription factors are also important. Foxo3a in particular appears to be "essential for maintenance of the hematopoietic dtem cell pool(ref).” “Hematopoietic development is regulated by a dynamic balance between HSC (hematopoietic stem cell) self-renewal and differentiation to mature effector cells. The balance between self-renewal and differentiation is of critical importance: too little self-renewal or too much differentiation may jeopardize the ability to sustain hematopoiesis throughout life, whereas excessive self-renewal and/or aberrant differentiation may result in leukemogenesis. The regulation of HSC self-renewal is not fully understood, but recent studies have underscored the importance of cell cycle, apoptosis, and oxidative stress response in HSC homeostasis. Recent data indicate that FoxO family members play a critical role in these physiologic processes in the HSC compartment and thereby regulate maintenance and integrity of HSCs(ref).”

There is no doubt that much more to be learned regarding the exhaustion of critical pools of healthy adult stem cells. In particular, in the Firewall Section for this theory of aging I speculate on approaches to maintaining or renewing the pools of adult stem cells.

Decline in the rate of differentiation of adult stem cells

This phenomenon of aging relates particularly to somatic stem cells (SSCs) of Type B described above and the role they play in continuing organ renewal. SSCs are capable of differentiation to produce normal somatic cells though they normally engage in cell division without cell differentiation. Unlike Type A stem cells, SSCs are specific to particular kinds of tissues but still may be capable of differentiating into several different cell types. They are capable of producing progenitor cells, Type C cells that can transform into regular somatic Type D cells in the course of additional rounds of cell division. For example, epithelial stem cells can differentiate into the various types of skin cells. Under conditions of signaled stress such as produced by a wound or burn, SSCs will produce progenitor replacement cells. The triggering of an SSC to produce a differentiated cell is due to cell signaling initiated by a shift in the pattern of gene expression, for example as initiated by organ damage. The cell signaling through which this process takes place is only now in the process of being discovered.

This matter of concern here is that aging is due to a slowing rate of organ regeneration due to declining SSC differentiation activity. This change in rate is thought to be associated with declines in numbers of or defects in aged SSCs, including shortened telomere lengths and replicative cell senescence, and is also due to the actions of certain proteins that accumulate in cells with age(ref, ref,ref,ref,ref)

When a SSC like a hematopoietic stem cell is triggered to produce a progenitor to a somatic cell of its type, such as a macrophage, basophil or eosinophil, a copy of the SSC is also produced along with the new more-differentiated progenitor cell. The number of SSCs stays the same but they age because of telomere shortening in the process of mitosis or telomeric DNA breaks and become less active with age. SSCs tend to express more telomerase than their normal somatic cell counterparts but significantly less than embryonic stem cells. In the normal course of a lifetime, SSCs have telomeres that progressively shorten as do other somatic cells and like other somatic cells are subject to cell senescence due to too-short telomeres(ref). It appears that with advancing age SSCs become progressively less responsive to producing their counterpart progenitor somatic cells. Loss of adult stem cells via telomere attrition provides strong selection for senescent, cycle-arrested (Type E), abnormal and malignant somatic cells, producing vulnerability to the diseases of old age.

There is another cause for concern regarding the longevity of stem cells as mentioned previously. The culprit is thought to be increasing amounts in cells of certain tumor-suppressor proteins, p16Ink4a and p19Arf in particular(ref). For a plain-language discussion of the process, see this reference. A new line of research(ref) focuses on four genes known to be implicated in both cancer and stem cell activation: Ink4a, Arf, Hmga2 and let-7b. P16/Ink4a in particular, a tumor suppressor gene, appears to become increasingly active with age in mice, humans and other mammals. It is a known mediator of cell senescence and biomarker of aging as well as a possible promoter of mammalian aging. P16/Ink4a works together with the three other genes to articulate a process of simultaneously protecting against cancers and shutting down adult stem cell function and regenerative capacity in aging tissues. Expression of Ink4a and Arf in the absence of a protein Bmi1 results in loss of self-renewing stem cells. The four genes involved, appear to switch on and off in a coordinated fashion that depends on age. Older stem cells don’t wear out or die from damage according to this line of reasoning; they are shut down. Increasing cancer protection is paid for by accelerated aging. This research is based on neural tissues in mice and the extent to which it can be generalized to other human cell types is still to be discovered.

The research relating aging to processes going on in the stem cell supply chain is relatively new and still sketchy. Many more discoveries are yet to come and I expect they will be coming with increasing frequency.

I continue to follow stem cell research as it is applicable to aging and has generated a number of blog posts related to the rapidly changing state of that field. There are several blog postings relevant to use of somatic stem cells for tissue regeneration including a May 2009 item State of autologous stem cell therapies, a June 2009 item Simple but powerful non-invasive adult stem cell cures, and a June 2009 item Dental Pulp Stem Cells - the big needle vs the tooth fairy

A July 2009 study report , TAp63 Prevents Premature Aging by Promoting Adult Stem Cell Maintenance, provides another piece of evidence supporting the Decline in Adult Stem Cell Differentiation concern related to aging. The report indicates that “that the p53 family member, TAp63, is essential for maintenance of epidermal and dermal precursors and that, in its absence, these precursors senesce and skin ages prematurely.” “TAp63 / mice (mice with TAp63 knocked out) age prematurely and develop blisters, skin ulcerations, senescence of hair follicle-associated dermal and epidermal cells, and decreased hair morphogenesis.” – “These data indicate that TAp63 serves to maintain adult skin stem cells by regulating cellular senescence and genomic stability, thereby preventing premature tissue aging(ref).

Another recent research study points to another aspect of stem cell differentiation. The study indicates that nano-scale substrate surface topography (micro characteristics of the surface on which a cell culture is grown) can significantly affect stem cell differentiation.  The study looked at human mesenchymal stem cells (hMSC) that can differentiate into a variety of cell types including chondrocytes, osteoblasts,  myocytes, and adipocytes.  It was discovered that when the surface consisted of relatively small nanotubes, hMSC adhered to the tubes without noticeable differentiation.  Somewhat larger diameter nanotubes (≈70- to 100-nm diameter)  “elicited a dramatic stem cell elongation (≈10-fold increased), which induced cytoskeletal stress and selective differentiation into osteoblast-like cells.” 

Problems in stem cell niches

Since there is such a tight health-interdependency between stem cells and their niches, problems with niches such as due to trauma can have serious consequences on the corresponding stem cell populations. “Understanding how extrinsic factors (niche factors) control hESC self-renewal and differentiation will allow us to culture and differentiate these pluripotent cells with higher efficiency. This knowledge will be essential for clinical applications using human pluripotent cells in regenerative medicine(ref). One key role of niches is maintaining stocks of stem cells in a state of protected quiesence. For example, in the osteoblastic niche “Interaction of HSCs (hematopoietic stem cells) with OBs (osteoblastic cells ) through signaling and cell adhesion molecules maintains the balance in HSCs between cell division/proliferation and quiescence. In particular, the quiescent state is thought to be an essential mechanism to protect HSCs from stress and to sustain long-term hematopoiesis (ref) . We can expect a continuing stream of such research relating stem cells to their niches.

Again the message is that aging is associated with breakdown or deterioration of the supply chain for new somatic cells. It is appropriate to start focusing on what is happening to adult stem cells. The Firewall section for this theory of aging discusses lifestyle factors and possibly-helpful dietary supplements as usual. It also characterizes some current experimental practices, and speculations about the far-ranging future possibilities for halting and reversing aging by means of stem cell supply chain interventions.

Relationship to the Programmed Epigenomic Changes theory of aging and particularly to Epigenomic Changes In Dna Methylation And Histone Acetylation.

The Stem Cell Supply Chain Breakdown and the Programmed Epigenomic Changes theories of aging are completely compatible and complementary. As mentioned before, the differences between the Types A, B, C, D and E cells are to be found in the epigenome, not in the genome – the genes in all body cells are the same. As Type A cells begin to differentiate they acquire epigenomic histories such as are due to histone acetylation and DNA methylation modifications. See the discussion of Epigenomic Changes In DNA Methylation and Histone Acetylation.

Research aimed at discovering exactly what the epigenomic modifications are when stem cells differentiate is still at an early stage. See for example the June 2009 publication Epigenetic Landscaping During hESC Differentiation to Neural Cells. It is known, however, that when a mature Type D body cell is reverted to being a Type A iPSC cell, its epigenetic markers are essentially erased. Turning to another study, “The researchers found that Jmjd1a and Jmjd2c, which encode enzymes that demethylate histone H3 lysine 9, regulate self-renewal in mouse ES cells: Depletion of Jmjd1a and Jmjd2c promoted differentiation, at the expense of self-renewal. Thus, these two histone modifying enzymes are required for maintaining pluripotency of ES cells(ref).”  Self-renewal vs differentiation of ES cells thus appears to be a matter of epigenetics.  As long as Jmjd1a and Jmjd2c are around, histone methylation is nipped in the bud and the cell acquires no epigenetic history due to such methylation.  Once methylation starts to take place the cell starts acquiring history and is prone to differentiation. Stem cell gene expression evolves with age reflecting changes in the epigenome. “In newborn mice, blood-forming cells (haematopoeitic stem cells, HSCs) rely on a transcription factor known as Sox17 for self-renewal, but adult HSCs rely on a different transcription factor, Bmi-1(ref).”

In the normal life cycle of an organism, the programmed epigenomic changes are exactly those that make for differentiation into the various cell types and are expressed by changes in DNA methylation and histone acetylation. So these three “theories” are in fact different but consistent viewpoints of aging. It is all starting to come together.

To the Stem Cell Supply Chain Breakdown firewalll

Relationships among the theories of aging

The theories of aging I have outlined are neither complete, independent nor final. Aging is not a simple process and there is much signalling between systems in the body. So all of the theories of aging covered here are part of a more comprehensive systems-oriented theory yet to be clarified. The age-related epigenetic signaling involving changing hormone levels, oxidative damage, glycation and lipofuscin generation and removal is complex and not yet well understood. Signals originating in the mitochondria affect DNA expression and visa-versa. Cancer and inflammation have a close relationship as do oxidative damage and tissue glycation. There is without doubt much interplay between the programmed mechanisms of aging and the presence of cell damage. Of the theories mentioned, perhaps the four most fundamental are Programmed Epigenomic Changes, Mitochondrial DNA damage, Telomere shortening, and Stem cell supply chain breakdown. It may require 30 or more years for a fairly complete systems perspective of what constitutes aging and the diseases of aging to emerge. In the interim, selected pieces of the picture are becoming clear and it seems that every few days or weeks a new piece of the puzzle is revealed.

As a way of summary, here is a first cut of how the 14 theories of aging relate to each other. The most general theory is that aging is defined by Programmed Epigenomic Changes. The age-related changes include an accumulation of damage affecting DNA, proteins, membranes, and organelles and decline in maintenance and repair on the cell level. On the more macroscopic level these changes show up as the usual indicators of aging including decline in organ function, decline in hormone levels, loss of muscle mass and grey hair. To be more precise, aging is not a program in itself but is a consequence of the totality of biochemical programs that operate in an individual over that individual’s lifespan. Those programs are species-specific and define typical average and maximum lifespan for each species. We don’t yet understand what the main programs are for most species including humans. We are starting to understand some of the subroutines and sub-subroutines, however, mechanisms that regulate cell cycles and the roles of key genes and proteins. For example we know there is a family of proteins called Sirtuins that are closely implicated in aging processes. One pathway, known as the calorie-restriction pathway, operates in a wide variety of organisms and in humans involves the sirtuin protein SIR1. Activation of that pathway appears to make up to 30% life extension available across a variety of species. See, for example these blog posts that relate to SIRT1: ref, ref, and ref.

In the previous Section I discussed how the Stem Cell Supply Chain Breakdown, the Programmed Epigenomic Changes (Epigenomic Changes In DNA Methylation and Histone Acetylation) theories of aging are completely compatible and complementary.

The Telomere Shortening theory of aging fits in neatly as a component of the Aging as Programmed Epigenomic Changes theory. Other aging programs could involve age-related increases in NF-kappaB and P16. These and associated increases could lead to age-related Decline In Adult Stem Cell Differentiation, an aspect of the Stem Cell Supply Chain Breakdown theory of aging. The basis for regeneration of aging tissues is provided by adult stem cells. P16 protects against cancers but induces premature senescence in progenitor cells. Progenitor stem cells play important roles in the maintenance of homeostasis in cardiac and other tissues and organ maintenance and repair after injury.

Oxidative Damage fits in as an important driver of aging and is implicated in the processes of several of the other theories of aging. We know for example that Oxidative Damage leads to Telomere Shortening. It is also a major cause of Cell DNA Damage which in turn can lead to Susceptibility to Cancers. Mitochondrial Damage can be brought about through Oxidative Damage or via signaling pathways conditioned by Programmed Epigenomic Changes. In turn, faulty mitochondrial functioning can lead to a number of metabolic disease conditions and faulty mitochondrial signaling can lead to errors in apoptosis and a multiplicity of disease susceptibilities including Susceptibility to Cancers and Susceptibility to Cardiovascular Disease. Just about every cellular process involves the operation of multiple feedback loops. Whether and how much exposure to oxidative conditions actually leads to aging depends on numerous factors such as the availability of antioxidant defenses. Natural antioxidant defenses decline with aging, another aspect of the epigenomic aging program driven by changes in the chromatin of cells which accumulate with age.

The feedback loops between many body systems are so tightly interrelated that it is difficult to say where one theory leaves off and another one starts. Considering the Decline in hormone levels and the Neurological degeneration theories, for example, it has long been known that "the neuroendocrine and immune systems are intimately integrated into one system that provides a complex homeostatic network(ref)." And auto-immune diseases like lupus erythematosus and rheumatoid arthritis can involve Chronic inflammation.

A simplified example of how seven of the aging theories link together is that Oxidative Damage activates NF-kappaB (the Programmed Epigenomic Changes theory of aging) resulting in expression of pro-inflammatory genes leading to a chronic inflammatory response. The inflammatory response is a mechanism in turn deeply implicated in Susceptibility to Cancers and Susceptibility to Cardiovascular Diseases, and Neurological Degeneration. Nothing is really simple, however. Whether a cancer cell is subject to apoptosis or proliferates is dependent on other epigenomic considerations such as the availability of a strong P16 or P53 defense.

Chronic Inflammation is a part of an aging-related program that can be triggered by numerous stimuli, is generally mediated by a gene activation sequence triggered by overexpression of NF-kappaB and related factors, and is an entry portal to several other of the aging related conditions including Tissue Glycation, Susceptibility to Cardiovascular Disease, Neurological Degeneration, and Susceptibility to Cancers. Telomere Shortening and Damage leads in time to cell senescence, apoptosis and mutations which in turn generate a number of the epigenomic-mediated aging conditions including Immune System Deterioriation, Susceptibility To Cancers, Susceptibility to Cardiovascular Disease, Neurological Degeneration, and atrophy of hormone-producing organs leading to Declines in Hormone Levels. The later is an example of the feedback between cell-level and organ-level functioning showing how damage on one level can cause damage on the other level as well.

The pathways affecting aging are complex and multiply interconnected. And gene expression as well as activation of factors like NF-kappaB are themselves dependent on the state of the epigenome and are therefore functions of age.

During chronic diseases there is generally a decline in the functioning of adult stem cells, cells essential for organ repair and regeneration. The same happens in the process of aging. The survival of adult stem cells and their ability to differentiate depends on the presence of growth regulatory signals and NF-kappaB plays an important epigenomic role in this process. Also, Telomere Shortening and Damage in adult stem cells may be a major cause of age-related Decline In Adult Stem Cell Differentiation.

Telomere Shortening and Damage itself, on the other hand, appears to be not inexorable because long-term population studies show that for some individuals telomeres actually get longer over substantial time periods. Telomere shortening may be caused by stress and oxidation, but may be mitigated by effective expression of telomerase which in turn requires the availability of telomerase binding proteins which is dependent on the states of histone acetylation of the DNA binding sites for these proteins – e.g. on their epigenomic states. Another of the Sirtuins, SIR6, appears to play a key role in maintaining telomeric integrity by preventing telomere looping and other damaging conditions, another link between the Programmed Epigenomic Changes and the Telomere Shortening and Damage theories of aging.

On the surface it appears that the 14^th theory of aging Stem Cell Supply Chain Breakdown is very different than the 12^th theory Telomere Shortening. And these two theories seem to be different than the 2^nd theory Cell DNA Damage. However, a number of recent studies show a growing web of relationships among these theories. For example, telomeric dysfunction may be at the heart of the decreasing capability of stem and progenitor cells to replicate and renew tissues with increasing age (ref,ref,ref,ref). The studies have looked at telomere shortening in hematopoietic stem cells (HSC), mesenchymal progenitor cells, osteoblasts and neural progenitor cells. One study suggests that proteins secreted from telomere-dysfunctional bone-marrow cells may provide accurate biomarkers of aging. As usual when it comes to aging, there are wheels within wheels. Among the many cellular proteins that influence telomere structure, function and enlongation are the telomerase binding factors TRF1 and TRF2 and less-directly shelterin-complex, PinX, Apollo and tankyrase(ref). TRF2seems to play a key role in the differentiation of neural stem cells(ref) as well as in cancer proliferation. In a closely related front, telomerase expression and TRF2 seem to play key roles in maintenance of DNA repair mechanisms in neural cells and stem cells(ref).

Lipofuscin Accumulation is driven by a history of metabolic processes dependent on the mitochondria, facilitated by oxidative stress and conditioned by the availability of substances which pump lipofuscin out of cells which depend on the epigenomic states of the cells. Declines in Hormone Levels may be the result of some kind of epigenomic program as well as a consequence of hormone-producing organ deterioration. In fact hormones are intermediary epigenomic factors because they themselves lead to changes in gene expression that affect the production of other hormones as well as disease susceptibilities and other markers of aging.

Additional discussions of how the theories of aging link to one another are provided in the Note New evidence linking the aging theories and in the blog entry Linking up the theories of aging. The Note describes crossover links among at least four of the theories: Programmed genetic changes, Oxidative damage to tissues, Chronic inflammation, and Telomere shortening and damage. The blog entry describes a link between the Telomere shortening and damage, the Programmed epigenomic changes, the Susceptibility to cancers and the Decline in adult stem cell differentiation (later subsumed under Stem Cell Supply Chain Breakdown) theories. In November 2009 I added a blog post that identified another important link between two of the theories: Breakthrough telomere research finding. As telomeres become critically short, the gene expression in affected cells changes so as to induce senescence and at the same time to affect the maintenance of epigenomic memory and nuclear organization, thereby contributing to organismal aging on the whole-animal level. Critically short telomeres deregulate epigenomic control and alter gene expression so as to create the changes we know as “aging.”

The above is just a starting sampler of known links among the theories of aging. It seems that research revealing a new link or shedding new light on existing ones is reported almost every week. As this happens, we are getting closer to understanding aging and what can be done about it. While we are not there yet we are getting closer to a unified theory of aging. Also it is already clear how an anti-aging firewall intervention intended to address aging according to one theory, e.g., taking astragaloside IV or Cycloastragenol as a supplement to activate telomerase expression, if it works addresses aging according to several other of the theories as well. The same is essentially true of most of the supplements in the combined firewall, they being antioxidants and/or inhibitors of NF-kappaB.

My firewall approach to longevity is a simple and practical one. I believe this approach is appropriate for older people given the current state of knowledge and relative ignorance compared to what will be known in coming decades. I started working with primitive computers in 1951 and have spent much of my previous career in computer-related work. The science and practice of longevity seems to be in about the same stage now as was the computer field back in 1955 - the same kind of excitement, the same rapid influx of new people into the field, the same competition among new ideas, the same rapidly increasing rate of knowledge and practical progress.

Given the mechanisms of aging characterized in each of the theories of aging, I lay out what I think can be done now to protect against those mechanisms. That is, for each theory of aging, I seek to identify a protective “firewall” that can be practically implemented today that will likely retard, stop or even reverse aging according to that theory. I am talking about lifestyle modifications and use of dietary supplements. In fact I am describing a highly personal matter – what I have been doing to prolong my life and live fully with a high quality of life while I am still alive. I have been studying this matter for 15 years now, and have gradually come to the program I am describing. This program is neither complete nor final nor guaranteed to work. I continue to modify it as new research findings come to my attention. It is quite different now than it was only eleven months ago when I created the first version of this treatise. I mention the research bases for the firewalls and offer further caveats at the end of the treatise.

III. FIREWALLS AGAINST AGING AND AGE-RELATED DISEASES

My general approach is to construct an in-depth defense (a firewall) against the causes of aging attributable to each theory of aging or cause of aging death, to the extent that is possible given current knowledge. A firewall can be compared to an infantry line of military defense. Rifles, machine guns, grenades, land mines, rocket launchers, fox holes and camouflage can be useful parts of such a line of defense. But it would not be wise to try to construct a defensive position using only one of these kinds of weapons, say only machine guns. Similarly an adequate defense against free radicals cannot be based on using only one antioxidant like vitamin C. Most of the supplements I suggest are pluripotent, i.e. are effective against many conditions. For example, in animal studies resveratrol has very strong positive effects on reducing heart inflammation, preventing cardiovascular disease, supporting bone structure and function, and maintaining loco-motor and balance activity. However, no one substance is a sure cure or preventative for a specific cause of death. Each substance works through its own biochemical mechanisms and has its own role in a protective firewall. I have attempted to construct practical firewalls that each contain multiple defensive measures, limited only by the state of research knowledge, by my own knowledge, and by the practical availability of firewall substances.

1. Oxidative Damage Firewall

Lifestyle

Basically the program is to avoid circumstances that produce large number of free radicals (ROS) in the body. Avoid unnecessary x-radiation and exposure to microwaves. Do not smoke and avoid breathing second-hand smoke. Use protective clothing, sunglasses and sunscreen under outdoors sunny conditions. Avoid exposure to heavy metals and toxic chemicals. For example, avoid handling arsenic-containing pressure-treated lumber without gloves or breathing the smoke of it burning. Adopt dietary habits featuring large amounts of fruits and vegetables, some fish, moderate consumption of meats and consciously limit eating foods that contain excessive omega-6 fatty and trans- fatty acids. Cook foods only at moderate temperatures and avoid browned food. Avoid fried foods, fast foods, hydrogenated oils and ones preserved with nitrites. Eat mercury-containing fish like tuna or swordfish only once a week. Use plenty of olive oil and drink ample amounts of green tea. Good foods include blueberries, sardines, and broccoli. Consume a moderate amount of dark chocolate daily – with 70% or greater cacao content. Consume alcohol in moderation and avoid stress. A small glass of red wine at dinner might help.

Supplements for the oxidative damage firewall

Anti-oxidants are highly effective in scavenging ROS and mitigating their damage. Different antioxidants have different properties with respect to the kinds of ROS ions they can neutralize, their fat solubility, the tissues they penetrate, their effective duration in the body and their biochemical mechanisms of operation. The body uses several different antioxidants as part of its own ROS defense system and I prefer doing the same rather than on relying on only one or two. My current antioxidant regime includes those in the foods mentioned above and: Vitamin C, Vitamin E, Vitamin D, alpha-lipoic acid, acetyl-l-carnitine, selenium, l-carnosine, co-enzyme Q-10, Essential Fatty Acid oils (EFAs), the hormone melatonin and plant-derived substances (phytochemicals which might be known as flavinoids, carotenoids or polyphenols) including resveratrol, curcumin, boswellia, ashwagandah, pycnogenol, green tea extract, olive leaf extract, lycopene, allicin and OPC grape seed extract.

These substances work through a number of different complicated channels to achieve their ROS-quenching impacts. [4]

A basic tenant of my firewall philosophy is to use multiple different defense mechanisms whenever they are available. I summarize the supplements I take daily and dosages in a table at the end of this article.

I touch on the subject of poisoning due to heavy metals and certain substances such as PCBs here. Some of these poisons produce large quantities of ROS; some operate through additional channels of toxicity. For example, it appears that exposure to heavy metals and arsenic reduces serum concentrations of carotenoids, reducing the body’s natural anti-oxidant defenses. Such poisoning can lead to degeneration and premature aging according to a number of the age-related theories, including immune system deterioration, neurological degeneration, susceptibility to cancer and susceptibility to cardiovascular disease. While acute poisoning with excessive blood serum levels of PCBs, lead, arsenic, cadmium or mercury requires intravenous chelation and other aggressive treatments, supplements can play a role in ongoing control of serum levels of these substances in healthy individuals and on the biological impacts of the presence of such toxins. L-carnosine is an important element of my firewall defense against toxic heavy metals like cadmium, lead, and mercury since it has an ability to chelate them (literally, to grab on to and combine with the molecules of these metals so the kidney and liver can excrete them). Further, according to animal experiments, certain antioxidants already in this firewall, vitamin C, alpha tocopherol, melatonin and alpha-lipoic acid in particular, can play roles in reducing the toxicity of heavy metals and PCBs, in some cases reducing it dramatically. Other components of the firewall defense against toxic metals are mineral supplements that compete for absorption and compete metabolically with such metals. For example, copper and selenium antagonize mercury. Calcium helps reduce lead and zinc helps reduce cadmium. Magnesium also appears to be very important for protecting cells from heavy metals. Besides protecting cells from certain forms of ROS damage, magnesium appears to be important for the absorption and metabolism of other supplements in the anti-oxidant firewall, including vitamin C and E and the B vitamins.

2. Cell DNA Damage Firewall

Lifestyle

Follow the basic advice I have already given above under the Oxidative Damages to Tissues firewall.

Supplements for the Cell DNA Damage firewall

The advice with respect to supplements is also the same. Curcumin, ashwagandha, resveratrol and green tea in particular appear to have important properties in regulating P53, P21, CASP9 and other genes which control apoptosis, inhibition of cell growth and cell cycle arrest so as to maintain a line of cells in a healthy state. These herbal substances act through complex biochemical and genetic pathways only now becoming understood, and are also important components of the firewall against cancers. Resveratrol, a polyphenol found in grape skins and red wine, activates an ancient life-extending chain of genetic reactions that works across species in plants as well as animals. It’s use can extend the life spans of small animals up to 30% and many researchers familiar with this substance take it regularly. OPC and other polyphenols may exercise similar effects. The firewall for the 13th theory of aging (Programmed Genetic Changes) and the ability of thirty-nine of the firwall substances to inhibit activation of the nuclear factor NF-kappaB is particularly relevant to DNA protection. Alpha-lipoic acid and many other of the combined firewall substances work to block the binding of NF-kappaB to cellular DNA. The results can be multifold, ranging from increased apoptosis of cancer cells to reduction of diabetes or atherosclerosis to a younger and less-wrinkled skin.

3. Mitochondrial Damage Firewall

Lifestyle

Again, follow the advice already given.

Supplements for the mitochondrial DNA mutation firewall

Certain supplements have the capability to penetrate into the mitochondria and prevent oxidative damage(ref). Acetyl-l-carnitine and alpha lipoic acid work synergistically(ref),(ref). This combination alone has been shown to extend the lives of some small animals by as much as 30% The R isomer of alpha lipoic acid can facilitate repair of mitochondrial DNA according to one study. It appears that the combination of Acetyl-l-carnitine and R-alpha lipoic acid can exert a preventative effect against Parkinson's disease according to a recent cell-level study(ref). Research on this relatively new combination of mitochondrial antioxidants continues and further interesting results can be expected.

Of course the previous list of supplements also applies, often in special ways. Resveratrol targets one of the enzymes that regulate the function of mitochondria, and has been shown to block high glucose–induced mitochondrial ROS production in certain animal cell lines. In the mitochondria. Coenzyme Q-10 is a key mediator for electron transfer and is a highly recommended supplement for people known to have a mitochondrial disease.

Telomerase activation via use of an astragaloside IV extract, as described in the firewall for the Telomere Shortening and Damage theory of aging, also provides mitochondrial protection and is part of this firewall. Telomerase expression does not always lengthen telomeres. When a cell is under stress, telomerase (actually its catalytic subunit TERT) migrates into the mitochondria. There TERT plays a DNA-protective role and improves mitochondrial functioning. Thia quote is from a study report entitled Telomerase does not counteract telomere shortening but protects mitochondrial function under oxidative stress. “While TERT maintains telomere length under standard conditions, telomeres under increased stress shorten as fast as in cells without active telomerase. This is because TERT is reversibly excluded from the nucleus under stress in a dose- and time-dependent manner. Extranuclear telomerase colocalises with mitochondria. In TERT-overexpressing cells, mtDNA is protected, mitochondrial membrane potential is increased and mitochondrial superoxide production and cell peroxide levels are decreased, all indicating improved mitochondrial function and diminished retrograde response. We propose protection of mitochondria under mild stress as a novel function of TERT.” Several other recent research reports supports this finding. For example, see the June 2009 publication Mitochondrial telomerase reverse transcriptase binds to and protects mitochondrial DNA and function from damage. Here is a May 2009 review study on the same issue.

4. Tissue Glycation Firewall

Lifestyle

Minimize eating substances having a high glycemic index, that is, sugars and substances your body converts to sugars. There are multiple reasons for this including and going beyond minimization of glycation within the body. Consuming low glycemic-index foods is very important for weight control, cardiovascular health and control of diabetes. High serum levels of simple sugars can contribute to the proliferation of cancers. Further, consuming high glycemic-index foods can lead to drastic changes in blood sugar levels affecting mental balance and one's sense of well being. It is a good idea to become familiar with the glycemic index so as to learn about the foods to avoid and other foods that can be substituted for them. For example,products containing corn syrup, soft drinks, sweetened breakfast cereals, white bread, refined-flour pastas and sugary deserts rank high on the glycemic scale, while whole-grain cereals, fruits, leafy vegetables and soybeans rank lower on the scale.

Specifically with respect to glycation, avoid eating large amounts of substances where glycation has occurred, including burned or browned meats and fast foods of all kinds. Eat foods cooked at lower temperature, avoiding those cooked by grilling, broiling and frying. Wear sunglasses to help protect against cataracts.

Some lifestyle adoptions offer longevity benefits that cut across several of the theories of aging, including inflammation. A good example is the so-called Mediterranean diet, which I am well aware of because I recently returned from two weeks in southern Italy. This diet features eating lots of vegetables and fruits, lean protein, fish, whole-grain pasta, lots of olive oil and moderate amounts of red wine. Besides reduced inflammation and glycation, there is strong clinical evidence that this diet enhances weight management, reduces stress, helps prevent cardiovascular diseases and cancers, improves blood sugar metabolism, helps neutralize ROS, and yields improved sugar metabolism that impacts on glycation. I ate more generously than normal while in Italy, but yet lost weight.

Supplements for the tissue glycation firewall

Two supplements are of particular interest. The first of these is l-carnosine. It acts both to prevent glycation in the body and to stimulate enzyme reactions that break up and eliminate already-formed AGEs. Carnosine is an effective scavenger of several unsaturated aldehydes (sugars) which induce DNA-protein and protein-protein cross-linking seen in ischemic-damaged cardiovascular tissues, in Alzheimer's disease and other neurodegenerative disorders, and in various inflammatory diseases. The other substance is a fat-soluble form of the vitamin B-1 known as benfotiamine. Benfotiamine inhibits the formation of AGEs. These firewall substances are particularly important for diabetics. They can mitigate or block the biochemical processes that lead to nerve, kidney, retinal and vascular damage associated with high blood sugar levels. Magnesium, another component of this as well as other firewalls, helps regulate blood sugar levels and prevent glycation. Other supplements in the overall list also contribute to this firewall, such as Vitamin C. Vitamin C is important for collagen metabolism; it is believed to increase the level of pro-collagen messenger RNA, and facilitates "hydroxylation," a process that facilitates collagen molecules to organize themselves in the best protective configuration to resist damage. There is much laboratory evidence that acetyl-l-carnitine helps to reduce glycation in eye lenses, the cause of cataracts. Phosphatidylcholine, another firewall substance, is a major constituent of cell membranes, and also plays a role in membrane-mediated cell signalling.

5. Lipofuscin Accumulation Firewall

Lifestyle

Protection against oxidative damage is a key strategy for minimizing the production of li[pofuscin. So, see the firewall for the oxidative damage theory of aging. Ihave no particular additional advice in this regard except to emphasize the importance of wearing sunglasses in sunlight to protect the retina from buildup of lipofuscin and druzen that can lead to macular degeneration.

Supplements for the lipofuscin accumulation firewall

Several of the antioxidants already mentioned function so as to reduce levels of lipofuscin accumulation in brain and other cells, including alpha-lipoic acid, CoQ10 and curcumin. Piracetam, another firewall component, appears to significantly decrease the formation of lipofuscin in neurons. I take two supplements which have a capability to pump lipofuscin out of cells. One is meclofenoxate (centrophenoxine) a ‘smart drug” used in Europe to treat symptoms of senile dementia and Alzheimer’s disease. The other is acetyl-l-carnitine, a pluripotent antioxidant also useful for mitochondrial health.

6. Chronic Inflammation Firewall

Lifestyle

Follow the suggestions previously made with respect to dietary habits. The Mediterranean diet can be very helpful.

Supplements for the chronic inflammation firewall

Some of the antioxidants previously mentioned have anti-inflammatory properties. For example, Vitamin C assists in the breaking down of histamine, an inflammatory substance produced by many allergic reactions. Vitamin D-3 suppresses the production of cytokines (inflammation-producing messenger substances exuded by cells) and is an important component of the firewall. Several of the the plant-derived phytochemicals are powerful anti-inflammatories, including aswagandah and boswellia. These as well as green tea and use of green tea supplements are important components of the firewall against rheumatoid arthritis, osteoarthritis, tensovitis and other inflammatory diseases. Bromelain is another anti-inflammatory phyto-substance in the firewall shown to be effective against joint inflammation. Several of these plant-based substances including ginger and curcumin are COX-2 enzyme inhibitors but, being natural substances, tend not to have the side effects of drugs designed for that purpose.

There is increasing understanding of the genetic mechanisms underlying inflammation and how supplements in the firewall can intervene in inflammatory processes. An example is low-level chronic inflammation in obese individuals. Their adipocyte (fat cell) genes express cytokines (TNF-alpha, IL-1beta, IL-6 and COX-2) implicated in cardiovascular diseases, type 2 diabetes and other pathological conditions. Curcumin and resveratrol are among the phyto-substances able to inhibit TNFalpha-activated NF-kappaB signaling in adipocytes and as a result significantly reduce their inflammatory cytokine expression. In fact, some 39 substances in the combined firewall are inhibitors of NF-kappaB cell signalling and therefore work to inhibit inflammation. See the discussion under the Programmed Genetic Changes Firewall. .

Control of tissue glycation and production of AGEs is important for control of inflammation. As saturation of tissues with AGEs begins to reach an advanced stage in older individuals, aggressive use of supplements to reduce them can be necessary to control the source of inflammation. See the tissue glycation firewall.

Also, potassium is part of this firewall. It can help the management of inflammation and some researchers believe it is very important for controlling arthritis. These anti-inflammatories together with vitamin B-6 helped me to vanish what once was a serious and worsening case of rheumatoid arthritis, much to the amazement of my rhumatologist . They were far more effective in this regard than the toxic anti-arthritic medicines that had been prescribed for me. From time to time in my life I have also been plagued with tensovitis and carpal tunnel conditions. These have also nearly disappeared since I have adjusted my regimes of these anti-inflammatory substances about seven months ago.

7. Immune System Compromise Firewall

Lifestyle

The main thing is to adopt a lifestyle which supports regular functioning of the immune system and avoids unnecessary challenges to it. Sleep at least seven and a half hours a night on a regular schedule, avoid chronically stressful situations, do mild cardiac exercise at least a half-hour each day, avoid situations likely to lead to infections, Treat infections promptly with lots of rest. And of course, avoid oxidative challenge as outlined previously. Having good family and friend relationships and a positive mental attitude can also help. Meditation and Yoga can also be powerful tools, although I do not practice these myself.

Supplements for the immune system compromise firewall

Antioxidants like those already mentioned contribute to lessening the load on the immune system. For example, the activity of antibodies and immune system cells such as phagocytes and neutrophils is stimulated by Vitamin C. In addition I take certain plant-related substances which specifically enhance immune system functioning as well as protect against infectious diseases. These include astragalus extract, the most concentrated form I can find, olive leaf extract and allicin. Each of these have significant antibacterial and/or antiviral properties. Allicin is effective in killing many strains of methicillin-resistant staphylococcus aureus (MRSA), the forms of staph resistant to conventional antibiotics. Olive leaf extract has strong antiviral properties and, in the laboratory at least, inhibits acute infection and cell-to-cell transmission of HIV-1. Astragalus has demonstrated a wide range of immunopotentiating effects and has proven efficacious as an adjunct cancer therapy. Among other capabilities, astragalus protects against common colds and many virus strains. Contrary to a long-established pattern, I have had only one common cold since I started taking substantial doses of astragalus two years ago. It appears that astragalus extract and its derivative astragaloside IV have important immuno-modulating effects. See the discussion in the firewall section for the Telomere Shortning and Damage theory of aging. Also, studies show that several of the firewall substances tend to have synergistic effects on immune system functioning. For example. in chickens at least it appears that astragalus polysaccharides and probiotics work together to support immunity(ref). The blog entry Vitamin D3 and the immune response describes new research(ref) published in 2010 indicating how vitamin D3 is essential for the mobilization of a T-cell immune response.

8. Neurological Degeneration Firewall

Lifestyle

Lifestyle habits seem to be very important for maintaining an active and capable brain and nervous system. Previous advice is all relevant, particularly that related to the immune system. The advice “Use it or lose it” seems to be applicable when it comes to the brain. Meeting mental challenges, movement and exercise seem to be essential for maintaining mental agility as well as body flexibility. There is evidence that regular physical exercise contributions to control of blood glucose levels which tend to rise with age and are implicated in hippocampal dysfunction and the onset of dementia and cognitive decline. Avid and regular pursuit of work, travel or a hobby can be helpful. Keep active. Close and frequent social interactions with friends and family are also helpful. And don't poison your brain with excess alcohol, toxic or illegal drugs.

Two blog entries relevant to diet are Diet and cognition, and Warding off Alzheimer's Disease and things in my diet.

Recent research related to brain neurogenesis highlights the importance of this conventional wisdom. The March 2009 issue of Scientific American reports research on what happens to neurons after neurogenesis in rats. Under normal circumstances, thousands of new neurons are generated every day in the dendrate gyrus of the hippocampus. Within a few weeks most of those neurons die if the animal’s life is unremarkable. However, if the animal is confronted with a sufficiently daunting and important learning task and successfully learns something complex and new, then many of the neurons will stay alive. This appears to be particularly applicable to learning that affects future behavior.

There is an intricate set of interrelationships between neurogenesis in the brain, mood stabilization and cognitive capability, age, exercise, mental task involvement, environmental factors such as stress and respect of circadian rhythms including patterns of sleep. The lifestyle patterns and activities suggested above promote neurogenesis. Mental or physical stress inhibits it. Maintaining consistent daily rhythms, mood stabilization, and proper neurogenesis are highly interconnected. For example, it is well known that aberrant daily rhythms may induce bipolar disorder episodes. A key underlying mechanism could be abnormality in hippocampal neurogenesis which is time-of-day dependent. Maintaining a regular daily pattern of activity and sleep is important.

Supplements for the neurological degeneration firewall

I have already mentioned the capability of acetyl-l-carnitine and alpha lipoic acid to penetrate into the mitochondria and prevent oxidative damage. This is particularly important in nervous system cells which regenerate very slowly. Pumping out lipofuscin from nervous system cells using acetyl-l-carnitine and meclofenoxate is also important for the same reason. Acetyl-l-carnitine also appears to have an ability to protect and increase receptors in the brain that normally decline with age. Besides removing lipofuscin, meclofenoxate produces DMAE when metabolized in the body, a natural substance found especially in fish and also produced in the human brain. DMAE, is a precursor to acetylcholine, an essential neurotransmitter. DMAE offers other benefits as well; for example it alters muscle contraction and is useful for increasing flaccidity and reducing wrinkles and in the facial region. I take another smart drug called piracetam which has an effect on brain energy metabolism and supports cognitive functioning. I also take meclofenoxate to improve my memory and cognitive capabilities. Also the hormones I am taking, pregnenalone, DHEA and melatonin, serve to enhance my mental functioning and my ability to be awake and sleep in regular cycles.

There is significant research establishing that curcumin promotes neurogenesis. This topic is treated comprehensively in the blog entry Neurogenesis, curcumin and longevity.

L-theanine is derived from green tea and crosses the blood-brain barrier. It promotes expression of the neurotransmitter seratonin. There is evidence that l-theanine is neuroprotective, and that it supports relaxation and enhances cognitive function. It appears to decrease the transmission of stimulating neurotransmitters while promoting the transmission of calming neurotransmitters. There is experimental evidence that l-theanine may be protective against strokes and may protect against the glutamate toxicity associated with Alzheimer’s disease. There is also evidence that the hormones I take, melatonin, pregnenalone and DHEA, have important positive neural and immunomodulating effects, as discussed later here.

L-carnosine, another component of this firewall, has a capability to reduce brain damage due to accumulation of beta-amyloid and possibly due to malondialdehyde or hypochlorite anions, factors in Alzheimer’s disease and other forms of senile dementia. See the blog entry Changing the threshold for neuromuscular fatigue in the young and old, carnosine or beta-alanine supplementation.

Excess homocysteine is associated with cognitive function decline. To buffer against this I take vitamins B-6, B-12 and folic acid as part of this firewall.

On another front, there is some evidence that excess angiogenesis (origination of blood vessels) is implicated in Alzheimer’s disease as well as in the proliferation of cancers. Alzheimer’s disease appears to arise through a combination of oxidative damage, inflammation and excess angiogenesis. Many of the flavinoids recommended in this firewall program work against all three of these causes. For example, green tea, curcumin, resveratrol and OPC are antioxidants, anti-inflammatories and have anti-angiogenic properties. Especially in combination, they show promise for prevention of Alzheimer’s disease. I have already mentioned other components of the firewall against Alzheimer’s disease and senile dementia: protection against DNA damage through use of antioxidants, and immunomodulation through taking hormones.

Resveratrol protects neurons against toxicity induced by beta-amyloid and provides another approach to defense agaainst Alzheimer’s disease.

Ginkgo biloba is another component of this firewall, a substance shown experimentally to enhance neurogenesis though not necessarily mental acuity(ref). It also appears that the levels of metals in the cerebrospinal fluid of Alzheimer’s disease patients is abnormal, for example showing an increased level of mercury. The supplements mentioned previously to control heavy-metal toxicity like l-carnosine and acetyl-l-carnitine are important for neurological health. Also, selenium has been shown to offset the toxicity of serum lead on the hearing function.

Some studies suggest that magnesium, another component of this firewall, can help in reducing the duration and frequency of headaches and improving learning, memory and cognitive skills for aged people. Apparently, magnesium locks into key brain neural receptors that participate in governing these mental capabilities.

As discussed earlier, there is evidence that mood disorders, bipolar and related diseases may be in part due to insufficient or abnormal neurogenesis. Neurogenesis is also promoted by several substances that are part of the anti-aging firewalls program: the neurosteroids melatonin, DHEA, and pregnenalone. Also, curcumin, resveratrol, Ginkgo bilboa and EPA fish oil according to published studies. Folic acid and the fish oil components DHA and EPA serve together to improve cognitive function and prevent depression, dementia and Alzheimer's disease, one of the mechanisms being the upregulation of neurogenesis(ref).I speculate that several other psycho-active firewall substances like piracetam, meclofenoxate, ginger extract and withania somnifera (ashwagandha) may also promote neurogenesis. I have been able to identify literature references that strongly suggest this speculation but none that experimentally confirm it.

As this discussion indicates, the firewalls provide in-depth defense against age-related cognitive decline and disease. Now, having recently turned 79, I am in an intensely creative period in my life and I believe my brain is working as well as or better than at any earlier time in my life. I intend to keep it that way for a long time to come.

9. Decline in Hormone Levels Firewall

Lifestyle

Lifestyle is felt to play a major role in maintenance and natural regulation of hormone levels. Here I would emphasize the role of regular exercise. On most days I do at least 45 minutes of mildly cardiovascular exercise – yard work, brisk walks in the countryside, swimming or treadmilling. Regular good sleep, avoidance of too much caffeine or alcohol are also important. And I believe mental activity is also important – like researching and writing this article.

Supplements for the decline in hormone levels firewall

Since hormones play such an important role in regulating multiple body systems, my approach as been to take supplements to maintain higher levels of some of the most important hormones than would occur naturally at my age. My objective is to maintain the level of functionality of a healthy 55 year-old. I do not take HGH or HGH promoters because they can have serious side effects – I tried once and got a serious case of arthritis. I do take two precursor “mother” hormones, however: pregnenalone and DHEA. Pregnenolone converts itself in the body into all other steroid hormones including DHEA, progesterone, estrogen, testosterone and cortisone. The extent to which it converts into estrogen or testosterone is a function of gender. Studies show it provides benefits in terms of lessening joint pain, improving cognitive function, enhancing skin condition and helping prevent joint pain. DHEA is another precursor hormone with natural levels declining with age. It is depleted by taking certain drugs and by certain disease conditions including AIDS and diabetes. Research indicates it is useful for treatment of adrenal insufficiency, depression, and SLE (systemic lupus erythematosus). I also take melatonin for regularity of sleep and for several others of its possible anti-aging benefits, including immune system regulation. Melatonin appears to be a regulator of the 24-hour circadian rhythm of biochemical, physiological and behavioral processes. I also use melatonin to speed the adoption of my body rhythms when I travel internationally across several time zones. On the mineral side, magnesium and calcium supplements are very important for maintaining my bone density as natural levels of density-regulating hormones decline.

Resveratrol is another important firewall substance for protection against age-related bone loss. Resveratrol "enhances proliferation and osteoblastic differentiation in human mesenchymal stem cells" according to one study(ref). According to another research report "In the present study, resveratrol was found to exhibit bone-protective effects equivalent to those exerted by hormone replacement therapy -- "(ref) . See also the discussion below regarding curcumin and protection against bone loss.

Hormone levels appear to be implicated in the pathogenesis or prevention of many cancers, particularly breast cancers in women and prostate cancers in men. Melatonin has been shown to be protective against breast cancers. In about half of all prostate cancers, there is a common gene alteration. In the presence of this gene alteration, estrogen-linked signaling helps trigger an aggressive form of the disease. Stinging nettle extract, saw palmetto, selenium, zink, and lycopene are substances in my firewall regime that contribute to control of estrogen, testosterone and other related hormone levels.

With respect to insulin resistance, chromiom piclonate contributes to both weight management and burning-off of extra insulin. Other substances in this firewall that assist in controlling excess insulin are DHEA, fish oil, CoQ10, alpha-lipoic acid, l-carnosine, vitamins C and E, and magnesium. These as well as exercise also contribute to weight management and control of glycation.

Again, the interrelationships among the theories of aging are complex. Most of the lifestyle suggestions as well as firewall substances have pluripotent effects related to several of the theories of aging.

10. Susceptibility to Cancers Firewall

Lifestyle

Most of the critical lifestyle actions have already been covered: minimize x-ray exposure, avoid sources of radioactivity, wear sunscreen, avoid contact with chemicals that induce carcioogenesis like paint removers, avoid foods with carciogenic additives. Do not smoke and avoid second-hand smoke. Eat a diet with a low glycemic index. Physical activity and regular exercise are also helpful, for example both in prevention of breast cancer and assuring positive health after breast cancer treatment(ref).

Supplements for the Susceptibility to Cancers Firewall

In this category I recommend a broad-spectrum approach involving different supplements each with different characteristics that fight cancer All the antioxidants previously mentioned help prevent cancer-inducing mutations. Vitamin D-3 has multiple cancer-fighting properties as do each of the phytochemical supplements I take. Resveratrol and curcumin, for example, activate the P53 gene in many strains of cancer cells, leading them to commit apoptosis. So does Green tea, OPC, lycopene and olive leaf extract. The genetics-related research evidence for these claims is impressive and growing though I cannot cite it here without losing the untrained reader.[5] The pathways of of operation of these substances can be quite complex. for example, it appears that curcumin acts to control the proliferation of neurogliaoma cells by modulating gene expression related to at least four different pathways: oxidative stress, cell cycle control, and DNA transcription and metabolism.(ref) A comprehensive review of the actions of curcumin in cancers can be found in the blog entry Curcumin, cancer and longevity.

A cluster of research reports has appeared during the last few years looking at mechanisms through which substances rich in phytochemicals (e.g. coffee, chocolate, turmeric, olive oil, broccoli, red hot peppers, green tea, garlic, blueberries, rosemary, oregano, sage) are cancer-preventative. While these foods have been studied for many years a new focal point has been moving to center stage - study of what these substances are doing in terms of gene expression as a key to understanding their therapeutic value. The blog post Nrf2 and cancer chemoprevention by phytochemicals reviews and provides citations to some of this research and discusses the role of the nuclear factor Nrf2 in phytochemical cancer chemoprevention. The blog entry Back to blueberries lists a number of research publications describing the pathways of action of pterostilbene, a powerful anti-inflammatory substance in blueberries, and describing the anti-cancer properties of this substance.

Omega-3 oils offer other cancer-inhibiting capabilities. Selenium is another substance in the firewall; it has its own mechanisms for inducing apoptotic death of tumor cells. Magnesium seems also to be useful for reducing the risks of certain cancers, such as colon cancer. Several of the substances in the firewall including curcumin, vitamin D-3, and lycopene have been well researched and show sufficient anti-cancer capabilities that they are being investigated in Phase I and Phase II clinical trials. Astragalus also appears to have anti-tumorigenic potential for certain cancer cell types includong colon cancer(ref).

NF-kappaB cell signaling is deeply implicated in both inflammatory and carcinogenetic processes which have long been known to be intimately related. A host of recent studies illuminate how NF-kB signaling is involved at the heart of inflammation, inflammatory diseases like arthritis, and cancer initiation and progression. As pointed out in the 13th firewall below, thirty-nine of the substances in the combined firewall are NF-kB inhibitors contributing to reduction of inflammation, preventions of cancers and, possibly even, organ renewal.

11. Susceptibility to Cardiovascular Disease Firewall

Lifestyle

Again, most of the critical lifestyle actions have already been covered. Do regular daily mildly-cardiovascular exercise(ref). But avoid extremes in exercising. Avoid foods and drinks with a high glycemic index. Maintain your weight within normal ranges. Monitor and maintain normal blood pressure, preferably under 130/70. Eat healthily, featuring vegetables, fruits and fish. Avoid browned or fried foods, foods cooked in trans-fats or saturated fats, fast foods and junk foods in general. Minimize stress and Type A behavior. Again, following a Mediterranean diet can be very helpful. Avoiding environmental toxins is also very important, starting with clean air and clean water. A recent study by Harvard School of Public Health and Brigham Young University(ref) researchers points to the importance of good air quality. It appears that improvements in air quality in the US, particularly in cities, added about five months to life expectancy in the U.S. over twenty years. If you can manage to live where the air quality is good, do so. Otherwise, using a HEPA air filter can help, particularly in the bedroom at night. If your water supply is poor or heavily chlorinated you can also consider installing a high-performance filtering system for your drinking and cooking water, one that can filter out lead and other heavy meals as well as microbes. Avoid drinking liquids that have been frozen or heated in plastic bottles and don't microwave food in plastic containers.

Supplements for the Cardiovascular Disease Firewall

Millions of people have been taking statins like Lipitor as part of a presumed firewall against cardiovascular disease, but I do not take them. Nor do I suggest taking statins for people without a history of heart disease and having a C-reactive protein score in the normal range. The US population has been convinced by an immense advertising and propaganda campaign to blame cardiovascular diseases almost entirely on the presence of a high level of cholesterol. There is a multi-billion dollar market for statins to lower cholesterol levels and understandably the drug companies involved want to protect their profits. New research shows that longevity of people without initial cardiovascular problems and with a normal C-reactive protein score taking statins is no longer than longevity of people who do not take them. The presence of a high cholesterol level is only one factor when cardiovascular diseases are concerned, and probably not the most important factor. Coronary artery occlusion can be caused by combinations of 14 known factors, many involving glycation and inflammation. A high serum level of cholesterol is only one of them. So, the supplements already mentioned that control glycation and inflammation are important – including the polyphenols, benfotiamine and l-carnosine. Carnosine also counts being an anti-ischemic agent as among its pluripotent capabilities.

Omega-3 oils are at the heart of this firewall. Dietary intake of sufficient omega-3 polyunsaturated fatty acids reverses the Omega-3/Omega-6 fatty acid imbalance mentioned previously as well as dysfunctional Ca2+ metabolism, facilitating increased efficiency of mitochondrial energy production. The result includes improved tolerance of ischemia and reperfusion. Even the crusty anti-supplements American Heart Association now recommends taking Omega-3 oils. The active components are DHA and EPA and it is important that the supplement capsules taken contain adequate amounts of them. The risk of heart attack or unstable agina was reduced 62% for every 1.24% increase of EPA and DHA in serum blood level compared to age-matched controls, according to a recently-published study of over 1,000 patients. I suggest 1500mg of EPA and 1000mg of DHA twice a day.

Of course, obesity is a major predictor of many cardiovascular diseases. Resveratrol, curcumin, chromium piclonate, L-theanine, quercetin, Vitamin A, and green tea extract contribute to weight management and reduction of abdominal fat. Consumption of green tea appears to strongly support the health of circulatory endothelial cells, preventing or delaying the onset of atherosclerosis. Green tea and L-theanine also reduce fatty acids in blood serum.

A number of the plant flavinoids that I have mentioned can contribute significantly to lowering blood pressure, in turn lowering risk of stroke, congestive heart failure and other problems. Research indicates that dark chocolate alone can make an important difference in this regard. In at least one study, taking acetyl-l-carnitine is reported to result in reduction of fat mass and increase in muscle mass, again predictors of cardiovascular health. There is also evidence that astragalus contributes to improvement of cardiovascular system health. This can be seen in clinical measurements associated with angina, congestive heart failure and acute myocardial infarct.

Lycopene is another component in this firewall as is allicin, a garlic extract. Epidemiological studies have shown an inverse relationship between tissue and serum levels of lycopene and mortality from myocardial infraction, coronary heart disease and cardiovascular disease. A recent meta-analysis of 25 systematic studies indicates that garlic extract is as effective in reducing blood pressure as the usual prescription beta-blocker medications given for this purpose.

Magnesium is another pluripotent supplement in the firewall that is useful for preventing cardiovascular diseases and hypertension. It helps to stabilize blood pressure, prevent arrhythmia, reduce cardiovascular inflammation, and reduce the consequences of congestive heart failure. Maintaining proper electrolyte (potassium-sodium) balance is also key for proper functioning of the heart as well a number of other systems including muscles, nerves, kidneys, and the digestive track. Since I get plenty of sodium in my salt intake, I also take a potassium supplement as another component of this firewall.

An excessive level of blood homocysteine is associated with elevated risk of heart attacks and stroke. These levels may result from inadequate supplies of certain nutrients including vitamins B-6, B-12, and folic acid. These nutrients are also part of this as well as other firewalls. Finally, Vitamin D is another important firewall component. A recent eight-year study of 3,258 men and women indicates that the higher the blood level of Vitamin D, the less is the chance of dying from heart disease - and the less the chance of dying from a number of other diseases as well.

12. Telomere Shortening Firewall

Lifestyle

The general rule is to keep your telomeres long while you have them that way. This means avoiding excessive or prolonged stress of all kinds be it environmental, physical or psychological. It means avoiding radiation, infections, bug bites, wounds, excessively strenuous exercise and heavily stressful human situations. Actually some stress such as through regular not overly-stressful exercise might help keep your telomeres long. See the blog entry Stress, exercise and telomere lengths. Positive mental attitude and good relationships can help. So can all the other firewalls already mentioned. Be aware that chemotherapy and radiation therapy or personal crises can take years off of your life through telomere shortening.

Supplements for the Telomere Shortening Firewall

A study of 586 women reports " -- the relative telomere length of leukocyte DNA was on average 5.1% longer among daily multivitamin users." Antioxidant regimes and the other firewall supplements already mentioned can help maintain health and minimize undue cell replication resulting in telomere shortening. Shortening may be due to an excess rate of cell duplication or, more directly, to single-strand breaks in the telomeric DNA, both most-frequently resulting from oxidative damage. In metabolic syndrome patients with coronary artery disease an association can be observed in circulating endothelial progenitor cells between oxidative DNA damage and telomere shortening. Therefore, anti-oxidant measures can be very useful for preventing telomere shortening and disease progress in such patients. The blog entry Vitamins, supplements and telomerase - upregulation or downregulation? cites research literature references on population studies coupling supplementation with Vitamin E, fish oils, Vitamin D3 and resveratrol with having longer telomeres.   L-carnosine also appears to reduce or even reverse telomere damage and shortening rates, at least in cultured human diploid fibroblasts. Studies going back to 1994 indicate that Carnosine can delay senescence and promote formation of a more juvenile phenotype in such cultured human fibroblasts, extending the Hayflick limit for reproduction of such cells by up to ten doublings. I conducted a literature review of l-carnosine a few years back and continue to be impressed by this substance. See the November 2009 Blog entry The curious case of l-carnosine . 

For the author, up until recently the Holy Grail of life extension has been to rejuvenate organs and perhaps whole animals by extending telomere lengths. The idea has been to reset cells and therefore reset organs and entire bodies to an earlier biological state. Young bodies generally have a vastly greater capacity to handle diseases of old age like cardiovascular problems, cancers Alzheimer's, Parkinson's,diabetes, etc. Either these diseases are much rarer in young people, or have less serious consequences, or don't occur at all. Young bodies know how to avoid or get rid of AGEs and lipofuscin and have much more effective antioxidant defences and DNA repair mechanisms than older ones. The basic concept of life extension through telomere extension is to reset bodies and the organs in them to an earlier biological age, to an age when the body has the capacity to shrug off the diseases of old age. If this theory of aging is correct then it relegates most of the previously listed theories of aging to secondary status. The central anti-aging firewall needed is to reset the body to an earlier age. The other firewalls in combination might be capable of getting one in a healthy active state to 100 or 115 years of age. An effective firewall against telomere shortening might get one to 250 to 500 good years of life, so I thought for many years. Since 1994, I have been aiming for 240 good years but might extend that target if biotech research moves fast enough. I waited 14 years for the emergence of a safe and effective telomere-extending technology.

Now there is much more knowledge available about telomeres and a dietary supplement is available that is believed to work to extend telomeres. However, as described above I no longer see telomere extension as being necessarily the central key to extraordinary longevity. Over the years there have been no reported small-animal experiments resulting in greatly enhanced longevity due to telomere extension. So, the notion that enhanced telomerase expression can by itself lead to radical life extension in humans remains hypothetical. However, there has been continuing research evidence suggesting that maintaining both telomerase expression and telomere lengths is key in any program for extraordinary longevity. I have also not given up on the concept of resetting cells, organs and bodies to an earlier biological age. Rather, I have expanded my viewpoint to allow this to come about also through additional means – such as through addressing two of the theories of aging I added after initially drafting this treatise: Programmed genetic changes and Decline in adult stem cell differentiation,

Achieving longevity through telomere extension is potentially tricky. One of the key transformations of a normal cell into a cancer cell is turning on the hTERT telomerase gene. Telomerase does not cause cancers but can cause them to go into high gear. Telomerase expression plays a role in tumor progression and it appears that the telomerase RNA component Terc is key as to what telomerase does regarding tumorgenesis. Telomerase-mediated telomere length maintenance could therefore possibly enable certain mutant cells to efficiently move into a fully malignant state, including metastasis. This is more than a bit scary, a high-stakes game. Possibly, the telomerase gene shutting down in older adults is an evolutionary defense against cancers.

Much of the basic research on telomerase has been done privately by the Geron corporation which owns 279 US and foreign patents related to the substance. Most of Geron’s focus has been on turning telomerase off in cancer cells – a promising new avenue for cancer therapy. In addition, Geron is the majority owner of TA Therapeutics, a Hong Kong subsidiary which is focusing on telomerase activation for organ renewal and prolonging the lives of AIDS patients. This company is focusing on specific extracts of traditional Chinese medicine which have proven capability to activate telomerase and extend telomeres. A key Geron patent indicates that one powerful telomerase activator is an extract made from the herb astragalus. A US company, TA Sciences, has licensed one such extract from Geron called TA-65 and is marketing it to the public for $25,000 for a year of treatment, called the Patton Protocol. So far, however, there has been only anecdotal evidence as to its efficacy. I am waiting for published research data which shows that the Patton Protocol indeed elongates telomeres or that any significant health benefits have resulted from its use.

Notwithstanding all of the above, I have been taking special astragalus-derived supplements that I am hopeful will result in telomere extension and that I believe are reasonably safe.

While the chemical identities of the TA-65 and TA Therapeutics telomerase activators are proprietary, Geron’s patents are in the public domain and show that a very potent but unamed telomerase activator is derivable from astragaloside IV, which in turn is a component of astragalus root. This activator substance is thought to be cycloastragenol. In larger but still very reasonable doses according to the patent, astragaloside IV itself appears to have the same telomerase activation capability. Up until mid-2008, astragaloside IV was not been available in supplement form in the US, so as an interim measure starting in July 2007, I took four capsules daily of the most concentrated astragalus extract commercially available – one with .5% standardized astragaloside content. The astragalacide content of my four daily astragalus pills was only 5mg daily, probably too little to exercise any significant telomere extension effect. There has been much research on the biochemistry and health benefits of astragulus in recent years and it is known that it has powerful effects in maintaining potency of the immune system, preventing viral diseases, and as an adjunct cancer therapy. Further, there is no evidence of astragalus inducing cancers. Of course, astragalus root is a mainstay of traditional Chinese medecine. Ginger-root extract also appears to have some telomerase activation capacity, and is also part of this firewall.

In late August 2008, I discovered that a supplement featuring high astragaloside IV content, 33 mg per tablet, had just come on the market at reasonable cost – RevGenetics’ Astral Fruit. I switched then to using this supplement, two a day, dropping the daily astragalus dose to two tablets. Early in 2009 RevGenetics started to offer Astral Fruit with a potency of 100mg per capsule and I switched to taking that. Starting in about September 2009 RevGenetics has also been marketing Astral Fruit C capsules containing 5 mg of cycloastragenol. As of mid-December 2009, I switched to taking a 5mg cycloastragenol capsule together with a simple astragalus-extract pill which may possibly increase bioavailability. On February 14 2010, I upped the daily cycloastragenol dose to 10mg. It is interesting that Revgenetics discontinued selling its Astral Fruit products in late December 2009 because a patent was finally issued to Geron covering Astragaloside IV and cycloastragenol. I understand that TA Sciences has progressively upped its recommended daily dose of TA-65 for its clients, and that the dose now stands at 100mg a day. TA Sciences continues to keep the chemical identity of the TA-65 substance a proprietary secret.

Astragaloside IV has been systematically studied for its medicinal properties only recently, mostly in Chinese and European research centers. It is an antiinflammatory, antifibrotic and antioxidant. It is known to have vasodilation and cardioprotective properties. It is neuroprotective and can protect the myocardium against ischemia/reperfusion injury. There are no reported negative side effects. Yet, my impression is that much is yet to be learned about this substance. Specifically, there appears to be little if any research available in the public domain relating astragaloside IV’s medicinal properties to its ability to induce telomerase expression. Cycloastragenol is thought possibly to be identical to Geron's TAT2 or to the TA65 product marketed by TA Sciences. The Geron patent suggests that 5mg of have started taking has roughly the same telomerase activating capability as 100 mg of astragaloside IV. Other than for what is in the Geron patent, there appears to be virtually no published information on the saftey or bioactivity of cycloastragenol. Assuming that cycloastragenol and TAT2 are indeed identical, it does appear based on a November 2008 report of a preclinical study that "exposure of CD8(+) T lymphocytes from HIV-infected human donors to a small molecule telomerase activator (TAT2) modestly retards telomere shortening, increases proliferative potential, and, importantly, enhances cytokine/chemokine production and antiviral activity.' I note that "modestly retards telomere shortening " is something that can also probably be said of vitamins C, D and E and is very different than saying "extends telomeres."

Several of the other substances in my combined firewall, including green tea, resveratrol, allicin and curcumin, are known to supress the expression of telomerase, at least in cancer cells. I am continuing with these substances because they have powerful anti-cancer and other beneficial effects. RevGenetics suggests that users wait three or more hours after taking such supplements before taking Astral Fruit. I do this, taking my other supplements in the mornings and evenings and Astral Fruit late afternoon. Presumably this schedule results in telomerase activation taking place for 6-8 hours a day with telomerase expression otherwise being shut off as protection against cancers. I am not sure that this staggering of supplements is necessary. See the blog entry Do resveratrol, curcumin and EGCG from green tea really inhibit the expression of telomerase? I need caution that human telomerase activation using astragaloside IV or cycloastragenol is very new and relatively little is known about it, including any potential hazards. I am unsure of what the results of taking this supplement will be but am monitoring the results carefully with significant excitement.

I have noticed a few small effects so far. The light patina of grey hairs on my mostly-bald scalp seems to me to be a bit thicker with a few black hairs as well. I have been nearly bald for over 30 years. It is known that in animal models at least, conditional telomerase induction causes proliferation of hair folicle stem cells (ref). It remains to be seen whether I will see more or darker hair as I continue with telomerase activation. Also there seems to be some increase in my sexual libedo but this may be a subjective impression. I also do not know if my daily schedule of alternating taking the telomerase activator with the other supplements with a few hours of separation is effective or whether I would be better off alternating every other day or even every other week. My guess is that my current pattern might be safer from a cancer prevention perspective, but that is only a guess.

Going to my blog using this link will reveal a large number of postings relating to telomeres and telomerase expression.

13. Programmed Epigenomic Changes Firewall

Lifestyle

There is nothing additional that can be said here. Macroscopic common sense suggests that if there are genetic aging programs at work, the previously-made suggestions are still valid.

Supplements for the Programmed Epigenomic Changes Firewall

The first theory I mentioned of aging as programmed genetic changes is the telomere shorting one and the firewall against it is described in the previous Section.

The third theory I mentioned of aging as programmed epigenomic changes suggests that at least limited age reversal on the organ level can be achieved by blocking the expression of NF-kappaB. It happens that many of the supplements in the Anti-Aging Firewall regimen identified up to this point powerfully inhibit NF-kappaB cell signaling. My research of the literature indicates that significant but different effects on inhibition of NF-kappaB expression and/or binding activity are exercised by each of the anti-aging firewall substances in this table:

Resveratrol	Pycnogenol	Curcumin
Green tea (egcg)	Ashwagandha	Astragalus
Astragaloside IV	Gingo biloba extract	Vitamin C
Boswellia	Allicin	Alpha-lipoic acid
Vitamin E	Vitamin D-3	Vitamin B-6
Folic acid	Grape seed extract	Avena sativa
Co-enzyme Q-10	EPA	DHA
Carnosine	Lycopene	Magnesium
Melatonin	Quercetin	Blueberries
Ginger	Dark chocolate	DHEA
Bilberry extract	Stinging nettle	Grape seed extract
Glucosamine	Benfotiamine	Acetyl-l-carnitine
Potassium	Vitamin B-12 (cobalamin)	Pantothenic acid

Substances in the combined firewall that inhibit expression or binding of NF-kappaB

Thirty-nine substances in the combined firewall! (and still counting) It is as if an overall objective of the firewall supplement program was to inhibit expression of NF-kappaB. In the case of antioxidants the protective mechanism is fairly clear. There is usually an ample supply of NF-kappaB in a cell’s cytoplasm, but it is sequestered there by proteins in the IkB family. Free radicals initiate a chain of signaling that causes unbinding of the NF-kappaB and its translocation into the cell's nucleus. Once in the nucleus, the NF-kappaB binds to and turns on a number of genes, potentially resulting in unwanted effects like inflammation and oncogenesis(ref). So, antioxidants reduce the numbers of such radicals and therefore inhibit the presence of nuclear NF-kappaB.

The majority of these thirty-nine pluripotent substances work through multiple additional biological channels (like suppression of TNF-alpha, IL-1beta and IL-6), are powerful anti-inflammatories, cause cancers to commit apoptosis, and have additional unique positive properties. At least three of them (resveratrol, Ginkgo biloba and curcumin) are capable of upregulating telomerase expression, differentiation and proliferation of certain somatic stem and progenitor cell types via the P13/Akt pathway. So far I have found only one substance in the firewall regime that activates NF-kappaB. This is phosphatidylcholine. As of the time of this update (Dec 8, 2008)I am continuing to look deeper into the NF-kappaB properties of the firewall supplements. Also, I am on the lookout for additional research that demonstrates inhibition of NF-kappaB cell signaling leading to clear-cut age reversal in organ systems. If the age-reversal results of NF-kappaB inhibition observed in the study of mouse skin are shown to apply to human tissues of various kinds, then it is possible that tweaking the combined firewall regimen listed here might allow going beyond aging stabilization to producing age reversal in selected organs.

Numerous studies point to the efficacy of specific NF-kappaB inhibitors in this list to address specific age-related health issues. Take the case of excess bone resorption due to osteoclastogenesis, for example, a situation typically created by the presence of inflammatory cytokines and implicated in breast cancer metastasis(ref) and in several degenerative bone diseases including rheumatoid arthritis and osteomyelitis. Curcumin inhibits both the NF-kappaB activation and osteoclastogenesis induced by by overproduction of the osteoclasts activator RANKL(ref). As mentioned previously, resvertrol, another powerful inhibitor of NF-kappaB activation, is also effective against osteoporosis,through induction of bone morphogenetic protein-2.

For those interested in delving deeper into the topic of inhibiting NF-kappaB as an anti-aging strategy, I have started an interesting discussion forum on this topic on the Immortality Institute site which can be accessed here.

Finally, I note that there seems to be paradox relating to the role of NF-kappaB and neurogenesis. On the one hand, all of the anti-aging firewall substances that stimulate neurogenesis (DHEA, pregnenalone, resveratrol, curcumin, Ginkgo bilboa and EPA fish oil) are also known to be inhibitors of activation of NF-kappaB, that is, translocation of NF-kappaB into the cell nucleus. This seems to imply that inhibiting the expression of NF-kappaB is consistent with if not necessary for neurogenesis to take place. On the other hand a number of published papers suggest the opposite - that activation of NF-kappaB is implicated in neurogenesis(ref). It is thought that that NF-kappaB may be part of a signaling pathway that is important for neurogenesis. The antidepressents Lithium and fluoxetine (not in the firewalls) are known to activate neurogenesis(ref, ref) and are also activators of NF-kappaB(ref,ref). Animal experiments show that proteins in the NF-kappaB family are expressed in actively proliferating neural progenitor cells. It is known that Tumor Necrosis Factor alpha activates NF-kappaB which in turn results in a proliferation of adult neural stem cells. There are multiple NF-kappaB proteins, and one explanation is that these could act differentially. Another explanation could be that the firewall substances primarily enhance neurogenesis via their antioxidant impacts, and that this effect exceeds the effect of inhibiting NF-kappaB insofar as neurogenesis is concerned. The signal transduction factors involved are complex and still only partially understood. So for the present at least, the exact roles of NF-kappaB expression or inhibition in neurogenesis remains unclear. Much is yet to be learned.

Stem Cell Supply Chain Breakdown Firewall

Assuming that this theory is correct, it would seem that an appropriate anti-aging intervention strategy would consist of: 1. extending the effective life of pools of somatic Type B and Type C stem cells, probably by keeping their telomeres long via protective measures as well as telomerase activation, 2. protecting the apoptotic capabilities of somatic cells and averting activations of pathways that could decimate such pools, and 3. halting the age-related decline in the rate of differentiation of the SSCs. I deal with the issues as usual in terms of Lifestyle and Supplements. However, for this theory I also include two additional subsections: one on stem cell therapies, and the other on radical future stem-cell based anti-aging interventions.

A. Lifestyle

All of the lifestyle suggestions mentioned previously are oriented towards the above three objectives, as is regularly taking the suggested supplements. "Caution is recommended in applying telomerase inhibition to kill telomerase-expressing cancer cells, because it would probably damage stem cells in essential organs and even increase the likelihood of secondary cancers(ref)

.

B. Supplements for the Deterioriation of the Stem Cell Supply Chain Firewall

One of the antidotes to organ aging, given this theory, would be to promote the expression of telomerase in SSCs. Reports of experiments of such telomerase-based SSC activation are beginning to appear in the literature. For example, "Resveratrol reduces endothelial progenitor cells senescence through augmentation of telomerase activity by Akt-dependent mechanisms." Experiments have been done activating HERT (the catalytic component of telomerase) for certain SSC types. For example by transfecting hTERT DNA into primary human marrow mesenchymal stem cells, those cells can be immortalized and induced to differentiate into chondrocytes(ref). “We have recently demonstrated that overexpression of human telomerase reverse transcriptase (hTERT) in hMSC (human mesenchymal stem cells) reconstitutes telomerase activity and extends life span of the cells.” In another experiment(ref), activating HERT in the hair follicle stem cells in mice results in the production of extremely hairy mice. It would seem that this intervention would be of the first type mentioned above but, surprisingly it is of the second type instead. In this case when the mice grew shaggy even with no TERC (the RNA component of telomerase) around, it was clear the follicle stem cell stimulation was due solely to TERT and that the telomere repair function of telomerase played no role(ref). Another report indicates “We show that TERT(ci) retains the full activities of wild-type TERT in enhancing keratinocyte proliferation in skin and in activating resting hair follicle stem cells, which triggers initiation of a new hair follicle growth phase and promotes hair synthesis(ref). Apparently, TERT can strongly promote differentiation of certain SSCs by a mechanism that is independent of telomere extension. It appears to work through activation of progenitor cells. For example. astragaloside IV can significantly potentiate the differentiation of preadipocyte cells(ref).

However, there seems to be some experimental evidence that stimulating somatic stem cells via telomerase may increase the probability of carcinogenesis when the HERT is expressed for a prolonged period(ref). In the hairy mouse experiment, the TERT transcriptional response strongly resembles that mediated by Myc, an oncogenic protein(ref). I speculate that protection against carcinogenesis in the course of such telomerase stimulation can probably be achieved through strengthening of apoptotic mechanisms such as P53, P16 and P21. Credence is given to this view by a very recent finding that mice which possess extra copies of both telomerase-creating and antitumor genes live 26% to 40% longer than their normal cohorts(ref).

There appears to be an open question regarding the tradeoff beween tissue rejuvination via stem cells and risk of oncogenesis. Recent research indicates that the P16/Ink4a gene, a tumor supressor, becomes increasingly active with age but at the same time shuts down adult stem cell function and differentiation capacity in aging tissues(ref). Activation of P16 to generate the protein P16/Ink4a and a few closely associated genes seems to be an important natural strategy in mammals for both fighting cancers and moving them along a programmed process of aging. To the extent that longevity is achieved by preventing cancers, a number of powerful substances are already in the combined firewall. Curcumin, green tea extract, resveratrol, ashwagandha and many of the other substances in the anti-cancer firewall fight cancers by various means. Can Ink4a be turned off on a temporary bases to encourage tissue renewal without incurring risk of oncogenesis? I don't know. There is a growing body of research relating telomerase, Ink4a, and NF-kappaB, but much of this appears to relate to cancer strains. For example, inactivation of Ink4a(P16) and activation of telomerase seem essential for immortalization of meningioma cells though there seems to be no evidence that one creates the other(ref). Given that these two steps are important in oncogenesis, it seems potentially dangerous to pursue them simultaneously in the interest of longevity.

(Update 27 July 2009). One experiment brings good news, saying that transduction with human telomerase has opposite effects on healthy and cancerous nerve stem cells(ref). On the one hand “Neural progenitor cells (NPCs) transduced with human telomerase reverse transcriptase (hTERT), the catalytic component of telomerase, have the potential both to proliferate indefinitely in vitro and to respond to differentiation signals necessary for generating appropriate cells for transplantation.” And on the other hand, for the cancerous NT2 cell line, “– following hTERT transduction. RT-PCR and telomerase activity data demonstrated that persistent exogenous hTERT expression significantly inhibited the differentiation of neurons from NT2 cells. Following retinoic acid induced differentiation, hTERT-NT2 cells produced only one fourth of the neurons generated by parental and vector-control cells.” NT2 is a neuronally committed human teratocarcinoma cell line. Not only does exogenous telomerase support the proliferation and differentiation of healthy stem cells, but it also inhibits the differentiation of cancer stem cells in the case of NT2. Of course, further research will be needed to determine how telomerase activation works in the case of other cancer stem cell types besides NT2.

The anti-aging regimen proposed in my paper addresses the issue of simultaneously activating telomerase while protecting against cancer by time-alternating 1) the taking of substances which activate Ink4a/P16 and inhibit P53/P21 deactivation (NF-kappaB inhibitors which are strongly protective against carcinogenesis) with 2) taking a telomerase activator (astragaloside IV). In a normal day I take the telomerase activator in the afternoon 4 to 6 hours after a number of the NF-kappaB inhibitors in the morning, and another set of NF-kappaB inhibitors of 4 to 6 hours after the telomerase activator in the evening. Several of these NF-kappaB inhibitors are phytochemicals like curcumin and EGCG from green tea that are known to activate Ink4a/P16. It appears that resveratrol, taken mornings and evenings, is a telomerase activator in some progenitor cell types (ref)(ref). Resveratrol also inhibits the expression of telomerase in many lines of cancer cells but this could mostly be due to the fact that it kills such cells. Although it is reputed to limit expression of telomerase in normal somatic cells, I have had difficulty finding research that directly supports this conjecture. I do not know what its net effect is. I also do not know how effective this scheduling is. I prefer to play it safe but so far my once-bald scalp is not getting shaggy as fast as the mice did. On the other hand, bald on top at around 55, there is more and more grey hair there now as I approach 80.

Regimen supplements and stem celll proliferation and differentiation

The research literature has some things to say about the impacts of certain substances in the existing combined anti-aging supplement firewall on differentiation and proliferation of stem and progenitor cells. A few hours of searching revealed a number of ineresting reports, including:

• May 2008: "Curcumin stimulates proliferation of embryonic neural progenitor cells and neurogenesis in the adult hippocampus."
• May 2006: “Curcumin-induced histone hypoacetylation enhances caspase-3-dependent glioma cell death and neurogenesis of neural progenitor cells.”
• May 2008: "Curcumin stimulates proliferation of embryonic neural progenitor cells and neurogenesis in the adult hippocampus."
• May 2006: “Curcumin-induced histone hypoacetylation enhances caspase-3-dependent glioma cell death and neurogenesis of neural progenitor cells.”
• October 2008: "Resveratrol reduces endothelial progenitor cells senescence through augmentation of telomerase activity by Akt-dependent mechanisms
• November 2005: "Resveratrol Inhibits Myeloma Cell Growth, Prevents Osteoclast Formation, and Promotes Osteoblast Differentiation ." Osteoblasts are stem-like cells responsible for bone formation; osteoclasts are cells responsible for bone destruction.
• October 2007: "Immortalization of epithelial progenitor cells mediated by resveratrol."
• February 2007: " Ginkgo biloba extract reduces endothelial progenitor-cell senescence through augmentation of telomerase activity." "Taken together, the results indicated that Ginkgo biloba extract delayed the onset of EPC senescence, which may be related to activation of telomerase through the PI3k/Akt signaling pathway. The inhibition of EPC senescence by Ginkgo biloba extract in vitro may improve the functional activity of EPCs in a way that is important for potential cell therapy."
• October 2007: "Melatonin Regulates the Viability and Differentiation of Rat Midbrain Neural Stem Cells."
• January 2008: "Melatonin Influences the Proliferative and Differentiative Activity of Rat Adipose-Derived Stem Cells."
• October 1998 "The major activity of Withania somnifera (ashwandagha) may be the stimulation of stem cell proliferation."
• October 2008:"Catechin promotes adipocyte differentiation in human bone marrow mesenchymal stem cells --." "Here, we studied the effect of several major green tea polyphenols on adipocyte differentiation in human bone marrow mesenchymal stem cells --." "In conclusion, our data suggest that (-)-catechin promotes adipocyte differentiation --."
• August 2007: Resveratrol enhances proliferation and osteoblastic differentiation in human mesenchymal stem cells via ER-dependent ERK1/2 activation
• August 2007: Dual bioactivity of resveratrol fatty alcohols: Differentiation of neural stem cells and modulation of neuroinflammation
• December 1998: Resveratrol Stimulates the Proliferation and Differentiation of Osteoblastic MC3T3-E1 Cells
• February 2005: The controlled differentiation of human neural stem cells into TH-immunoreactive neurons in vitro  Discusses use of extract of ginkgo biloba to promote differentiation
• January 2008: Effects of Melatonin on the Proliferation and Differentiatiation Activity of Rat Adipose-Derived Stem Cells

C. Stem cell therapies

It is important first of all to recognize that every proposed, experimental or practical stem cell therapy in an anti-aging intervention in the stem cell supply chain. They all involve activating, introducing or re-introducing stem cells for particular purposes whether those purposes be curing cancer, healing wounds, re-growing hair, treating neurological conditions or what have you. It is beyond the scope of this document to cover what is going on with stem cell therapies. However, I can point to recent blog entries describing recent progress on some such therapies and the interested reader will find they provide a good sample of what is going on. In order of appearance:

1. The January 28 post Geron in the news again relates to a clinical trial using proprietary oligodendroglial progenitor cells to treat acute spinal chord injuries. The trial has recently been put on hold because a small number of animals previously injected with the trial substance developed microscopic cysts. Although those cysts are reportedly nonproliferative, confined to the injury site, and had no adverse effects, the FDA felt it prudent to halt the trial at least temporarily.

2. Trojan-horse stem cells might offer an important new cancer therapy is about a stem cell therapy with a reverse twist. Since mesenchymal stem cells circulating in the blood are attracted to and seek out cancer cells, it is possible to attach a payload molecule to mesenchymal stem cells which cause them to kill cancer cells but not normal cells. There are other uses of stem cells as delivery vectors. For example, Stem cell transplants can be used to transfer new genes into patients, for example to protect them from some of the negative effects of chemotherapy treatments(ref).

3. The May 23, 2009 post State of autologous stem cell therapies provides a general discussion of therapies that are based on extracting, culturing and re-introducing a patient’s own Types B and C stem cells. How I opened the post is worth repeating: “I searched the news this morning for items related to stem cell disease therapies.  I found over 60 items.  My impression is that the situation is a bit like commercial aviation was in 1926: everybody is talking about it, visionaries are sure it will be a very big thing, there is a lot of disconnected activity going on all over the place, and safety is a big question.  And, the regulatory rules-of-the-game still have to be worked out.  Most potential stem cell therapies are still far from being part of mainline medicine and it is difficult to make sense about where things stand.”

4. The post A genetic fix for obesity? describes research involving introduction of a plant-based genetic pathway in mice that increases metabolism of fatty acids and induces resistance to diet-related obesity.

5. The post Genetic or antibiotic prevention for HIV? discusses a possible genetic fix that would prevent the occurrence of HIV.

6. The post More research insight on gray hair and adult stem cell reproduction discusses the relationship of gray hair to declines in melanocyte stem-cells, the possible basis for a future stem cell therapy.

7. The post Simple but powerful non-invasive adult stem cell cures discusses experimental stem cell treatment of Scleradactyly and blindness caused by corneal disease.

8. The post On cancer stem cells discusses a new approach to understanding and treating cancers. The concepts of the stem cell supply chain apply to cancers as well as to normal cells and as long as cancer stem cells are present, no amounts of radiation or chemotherapy are likely to be able to keep a cancer from recurring.

9. The post Now hear this discusses reasons for hearing loss including decline in the rate of differentiation of hair follicle stem cells in the cochlear canal, and speculates on the use of stem cells as a therapy for hearing loss(ref). See also this article regarding restoration of hearing through the growth of cochlear hair cells generated from stem cells in mice.

10. The July post Embryonic Stem cell research news focuses on research developments related to ESCs, particularly the transcription factors affecting their pluripotency and differentiation. Among the many topics discussed is using human ESCs to generate “natural killer” immune system cells that can can combat  cancers.

11. The July post Hair stem cells looks in detail at the roles of hair follicle stem cells a possible approach to reversing baldness via telomerase activation.

12. Among other matters mentioned in the post Autoimmune diseases and lymphoma: Part I: focus on Lupus is a ”five-year study to see whether a therapy using transplantation of hematopoietic stem cells, blood stem cells found in bone marrow, can produce long-term remission for patients with severe, treatment-resistant systemic lupus erythematosus(ref).”

13. The August 2009 post Update on cancer stem cells reports new research indicating two advances with respect to cancer stem cells (CSCs): first, development of a high-throughput screening approach for agents that have high toxicity for epithelial cancer stem cells; second, identification of a compound that has very high toxicity for breast cancer stem cells, salinomycin.

14. In the August 2009 post Autoimmune diseases and lymphoma – Part III: focus on lymphomas, I discuss treatment options for lymphomas, including use of stem cell therapies. I discuss also discuss problems experienced in connection with such therapies: relapse in the case of autologous stem cell therapy, and Graft-versus-host disease in the case of transplantation from unrelated donors. Both problems result from failure to deal with all the factors involved. Of course, a transplantation from an unrelated donor is likely to be rejected by a patient’s own immune system. An autologous transplant will involve stem cells that have the same genetic susceptibilities that the patient had in the first place. For how this situation can be dealt with, please see the discussion below on Curing Genetic Diseases.

15. The September 2009 post More mTOR links to aging theories relates mTOR to the stem cell supply chain, and much of the content of that post is already embodied in the above discussion.

Radical stem-cell based anti-aging interventions

I engage here in two speculative exercises as to how interventions in the stem cell supply chain might in the future have significant impacts on future longevity. The first relates to curing genetic diseases, the second as to how the stem cell supply chain might possibly be kept active indefinitely.

Curing genetic diseases

One of my blog pots points out how defects in two genes, Fas and FasL are implicated in a number of diseases and may cause such diseases or increase susceptibility to them.  The post leaves open the question of what can be done for people with such defective genes and suffering from associated diseases.  I speculate that the treatment process will turn out to be something like this:  

1.  As a first step, a few drops of blood or a tiny piece of skin would be taken from a person suffering from a disease known to be associated with certain defective genes that have been detected in the patient. For example the defective genes could include Fas and FasL in the case Lupus or Lymphoma .

2. The cells in the blood or skin would be reverted to being induced pluripotent stem cells, known as iPSCs.  Technolgy to do this is now being perfected. See the post Rebooting cells and longevity.

3. Using laboratory techniques of gene splicing, sometimes called DNA editing, the defective Fas, FasL and/or possibly other defective genes will be stripped out of the chromosomes in these cells, and good versions of the same genes pasted in their place.  This is accomplished by established techniques of genetic engineering.  The results will be the patient’s own pluripotent stem cells with good genes in place of the defective ones. Call these corrected induced pluripotent stem cells ciPSCs.   

4.  The ciPSCs will be encouraged to reproduce in the laboratory to increase their numbers. This is something commonly done. 

5.  The ciPSCs will be introduced back into the patient under conditions that they will differentiate into the stem cell types and somatic cell types involved in the disease process.  Discovering exactly how to do this is probably the major challenge involved in the whole process.  Success has already been realized in getting embryonic stem cells which are like iPSCs to differentiate into certain cell types.  See the July blog post Embryonic Stem cell research news.  Also, we know no immune reaction can be expected because the ciPSCs are the patient’s own cells.   

6.  As the ciPSCs reproduce and differentiate in the body, they will produce adult stem cells and differentiated tissue cells that are free of the genetic defect.   The genetically corrected cells will supplement and possibly in time replace the genetically defective ones.  In principle at least, as fewer and fewer body cells possess the genetic defect and more and more are normal, susceptibility to the disease should decrease, the hope being that the disease will go away.  The process can be compared to replacing defective car parts with rebuilt ones from the original manufacturer. 

Why such a complicated process using corrected induced pluripotent stem cells?  If the disease is in T-lymphocytes for example , why not just collect some T-lymphocytes from the patient, correct the genetic defects in them, reproduce them and introduce them back into the body?  I think a major problem would be that the body’s hematopoietic stem cells that make new  T-lymphocytes would continue to have the genetic defect in them and  would continue differentiating and producing new defective t lymphocytes.  So, I believe it will be necessary to go to the stem-cell level to have a lasting fix.  Many genetic engineering experiments have been tried with ordinary cells but with only poor or mixed success. 

If the kind of treatment process I outlined can be realized and fine-tuned, it could possibly be used to control or vanish most diseases related to genetic defects, not just defects in Fas or FasL.  Step 5 will require significant disease-related research if it is to be used in humans. Introducing Type A cells into a live organism can lead to tumors such as teratomas if the signaling conditions are not correct. We have already seen a positive result using this kind of process in laboratory animals. Mice have been rescued from sickle cell anemia this way(ref). Also, this general approach has been used to cure human cells of Fanconi-anemia. "Most importantly, we show that corrected Fanconi-anaemia-specific iPS cells can give rise to haematopoietic progenitors of the myeloid and erythroid lineages that are phenotypically normal, that is, disease-free. These data offer proof-of-concept that iPS cell technology can be used for the generation of disease-corrected, patient-specific cells with potential value for cell therapy applications(ref)." Very recently, research has been reported in applying this general approach to "familial dysautonomia (FD), a rare but fatal neuropathy that has been impervious to functional analysis and drug validation(ref)."

The possibility of keeping the stem cell supply chain active indefinitely

The basic concept of this speculation is to feed in a trickle of corrected Type A iPSC cells through adult life so they can replenish the pools of Types B, C and D cells. The cells would be obtained by the same process as described in steps 1-4 above for curing genetic diseases. I do not think that will constitute a problem. The challenge will be 1. how to introduce the corrected iPSCs into the body in a way that is safe and effective and 2. How to get the introduced Type A cells to differentiate in a controlled manner so as to refresh the pools of Type B and Type C cells. The good news is that there have been laboratory successes at introducing Type A cells and having them differentiate in a controlled manner into different stem cell and ultimately tissue types. The needs are to gain much deeper understanding as to how that process works for different stem cell types and to gain mastery of control over it. A long September 25 2009 blog entry The stem cell supply chain - closing the loop for very long lives goes deeper into this speculation. I intend to keep reporting research related to this topic in my blog.

*

IV. THE LIFE STYLE REGIMEN

To get to live to age 200 or 300, you have to live to 100 first. The dietary supplements may help you live a very long life but are almost surely insufficient to get you to 100 without adoption of a healthy lifestyle. In fact, the dietary and lifestyle recommendations go hand-in-hand and support each other. For example, some of the supplements can help with weight loss; others can support stamina for exercise; others yet can help provide mental clarity for intellectual activities. Likewise, mental clarity can help provide the resolve necessary for following both the lifestyle regimen and the supplement regimen.

Many of the lifestyle recommendations listed above show up in several firewalls. I pull them together into a single list here, adding a few more tips. They are closely parallel to the “conventional wisdom” of longevity that appears frequently in popular books, news reports, articles, Blogs and folk tales. There is now an increasing body of research that reveals the biomolecular mechanisms underlying such conventional wisdom. For example, exercise changes the body’s biochemistry by activating a number of genes and stimulating neurogenesis, hormonal, histological and other positive changes. And exercise appears to help preserve telomere lengths.

Also, large-scale population studies strongly support this conventional wisdom. For example, a study(ref) of 2357 healthy men (mean age, 72 years) within the Physicians Health Study looked at biological and key lifestyle factors that contribute to living to 90 years of age. “The probability of a 90-year life span at age 70 years was 54% in the absence of smoking, diabetes, obesity, hypertension, or sedentary lifestyle. It ranged from 36% to 22% with 2 adverse factors and was negligible (4%) with 5.”

Specific reasons for most of these recommendations are already given in the discussions for the firewalls. While the list seems very long, once these behavioral prescriptions are internalized they recede into the background and are recalled only when needed – like at a party where everyone seems to be gorging on beer, sugar sodas, pork rinds, twinkies and potato chips.

Regular exercise

The blog post Exercise, telomerase and telomeres relates to how exercise promotes the expression of telomerase in cells and therefore promotes longevity. I suggest 45 minutes a day of mildly cardiovascular exercise such as swimming, vigorous yard work, cross-country skiing or walking at a brisk pace. In the winter in New England, many days I do 47 minutes of walking at a pace of 2.8mph and incline of 5 on my treadmill. A TV in front of the treadmill with a DVD player helps to keep my mind busy. I tend to use the machine during my favorite news-hour which helps keeps me on a daily exercise schedule. It is good to pursue a variegated exercise program, one that involves multiple joints and muscle systems. When possible I swim, simulatneously exercising a number of my muscle and joint systems. Balancing and proprioceptive exercises, ones that involve whole-body movement and awareness of states of body positioning, can help older folks maintain stability in movement and prevent debilitating falls. Some of the marital arts like Judo and Tai Chi can do the same. And so can dancing and playing ping-pong, tennis or basketball. Stretching exercises can also be important for staying coordinated and maintaining ease and range of motion. Exercise with weights can be used to maintain muscle and bone mass.

A gene coactivator known as PGC-1alpha is central to the metabolic process and appears to be the mediator of health benefits produced by exercise. A comprehensive discussion of this can be found in the blog entry PGC-1alpha and exercise.

Sleep and Rest

Be in a regular daily rhythm of wakefulness, activities and sleep. Sleep 7 to 9 hours a night on a regular schedule. I find taking 3mg of melatonin a half-hour before bedtime helps me to go to sleep promptly. Getample rest and sleep when recovering from infections or diseases.

Avoid or Minimize

Avoid circumstances that produce large number of free radicals (ROS) in the body. Avoid unnecessary x-radiation and exposure to microwaves. If your doctor recommends a cat scan, make sure it is really necessary. And if you do have to have a cat scan, fluoroscopy or other intensive X-ray procedure, load up on antioxidants before and after the event. Absolutely do not smoke and avoid breathing second-hand smoke. Use protective clothing, sunglasses and sunscreen under outdoors sunny conditions. Do not use tanning booths. Avoid exposure to heavy metals and toxic chemicals. For example, avoid handling arsenic-containing pressure-treated lumber without gloves or breathing the smoke of it burning. Do not consume liquids that are in plastic bottles that have been frozen or overheated, such as water bottles baked in a car in the summer sun. Avoid situations likely to lead to infections. Wash your hands frequently; many infections are communicated by touch. Avoid unnecessary stress, be it physical, circumstantial or emotional. Too vigorous exercise can be harmful or dangerous.

Avoid contact with carcinogenic chemicals and substances like tars, paint removers, solvents and insecticides.

Avoid end-game thinking when it comes to life, ideas like “Now that I am retired I don’t have to do anything and can just take it easy” or, “After I stopped working, nobody seems to be interested in what I can contribute anymore.” If you want to live for a very long time, adjust your thinking and life planning accordingly. If you really believe in longevity, you can use the same life-planning approach when you are 78 that you used when you were 28.

Minimize eating substances having a high glycemic index, that is, sugars and starchy substances your body converts to sugars. No candy bars, though a little 70% chocolate is OK. If you must eat ice cream, make it just a little. And don’t be fooled: frozen yoghurt has just as much sugar even if it is "low fat." Avoid sugary or caffeinated “power” soft drinks. Avoid junk foods that contain calories or fats and few nutrients like twinkies and potato chips. Avoid fried foods, fast foods, hydrogenated oils and ones preserved with nitrites. Eat mercury-containing fish like tuna or swordfish only once a week. Be careful eating raw seafood that might come from contaminated waters. Avoid excess consumption of coffee. I normally drink two large cups of 50% decaffeinated and 50% caffeinated coffee per day, mostly in the mornings.

Don't poison your brain with excess alcohol, toxic or illegal drugs. Damage could be permanent. Avoid usage of over-the-counter or prescription medications unless you really need them and fully understand what they are doing and their negative as well as positive impacts. Pay attention to the fine print. And don't expect all the possible negative impacts to appear in the fine print. For example, many medications can inhibit the expression of telomerase or the proliferation of progenitor and stem cells

With respect to glycation, avoid eating large amounts of substances where glycation has occurred, including burned or browned meats and fast foods of all kinds. Eat foods cooked at lower temperature, avoiding those cooked by grilling, broiling and frying.

Don't microwave or cook food or beverages in plastic containers.

If you can live where there is good air quality, do so. If you live in a city or location with polluted air, use a HEPA air filter in your workplace and bedroom at night. Wear sunglasses outdoors in the summer to help protect against cataracts. Even if it might feel good, sun damages your skin. Protect yourself with a wide-brim hat outdoors in the summer or at high altitudes. If your water supply is poor or heavily chlorinated, install a high-performance filtering system for your drinking and cooking water, one that can filter out lead and other heavy meals as well as microbes. And of course, don’t swim in tropical waters infested by parasites. . If you have to spend time in a city where the air is heavily polluted by particulate matter like Mexico City or Sao Paulo, you can bring along a small portable electrostatic particle precipitator which you can use in your hotel room.

Good Eating

Adopt dietary habits featuring large amounts of fruits and vegetables, some fish, moderate consumption of meats and consciously limit eating foods that contain excessive omega-6 fatty and trans- fatty acids. Cook foods only at moderate temperatures and avoid browned food. Use plenty of olive oil and drink ample amounts of green tea. Good foods include blueberries, sardines, and broccoli. Consider a Mediterranean Diet which features eating lots of vegetables and fruits, lean protein, fish, whole-grain pasta, lots of olive oil and moderate amounts of red wine. You can consume a moderate amount of dark chocolate daily – with 70% or greater cacao content. A small number of mixed nuts every day can also help. In any event, consume alcohol only in moderation. A small glass of red wine at dinner might help.

Substitute healthier foods for “bad” ones. For example, products containing corn syrup, soft drinks, sweetened breakfast cereals, white bread, refined-flour pastas and sugary deserts rank high on the glycemic scale and are “bad,” while whole-grain cereals, fruits, leafy vegetables and soybeans rank lower on the scale and are better.

Monitor your health

Maintain your weight within normal ranges. Monitor and maintain normal blood pressure, preferably under 130/70.. Take full advantage of the resources of your health provider. Have your blood lipids and c-reactive protein checked regularly. Have annual physical exams and other lab tests and examinations appropriate to your age and specific medical conditions. Have regular dental exams and cleanings and keep your oral health and teeth in shape.

Good mental and social habits

There is evidence that a positive mental attitude and regular participation in intellectually-challenging activities contribute towards longevity. As for your brain, “Use it or lose it. ”Social participation is also important. Enjoying the companionship of a partner, intimate friends or relatives seems to be key factors correlated with extended longevity. Meditation, Tai Chi, Yoga, Judo and Karate are thought also to be powerful tools although I do not practice these myself.

Keep going!

Avid and regular pursuit of work, travel or a hobby can be helpful. Obtain prompt and competent treatment for any infectious disease. Get orthopedic problems that are fixable by surgery (like a torn rotator cuff) fixed. If you are laid up by a sickness, broken leg or other orthopedic problem, do not withdraw. Instead, find forms of exercise that will work and keep intellectually and socially busy anyway. Do physical therapy to get yourself back in full operating condition as soon as possible. Find and stay in contact with a doctor or health practitioner concerned with keeping you healthy as well as with fixing any problems you may have. Link-up with others committed to life extension and health. And stay on your anti-aging supplement regimen.

V. THE SUPPLEMENT REGIMEN

The table below summarizes the supplements I recommend for the firewalls and daily doses.

First a comments on “Why so many pills,” and “How effective are these firewalls?”  When I have shared some of the information in this article with friends and colleagues I have been typically told “I would like to start some of those supplements myself but don't want to take all those pills in your combined firewall. Can you tell me the ones that are REALLY important?” I have therefore come up with a top-10 supplements list, but I know it is not sufficient to provide the protection of the firewalls listed here. There is a common but false cause-and-effect presumption that if there is a problem there probably is some single solution to it – like a cure for cancer, a magic bullet solution. Unfortunately, things don't work that way. The bodies of higher animals are extremely complex, and so are the signaling systems, cells, genes and epigenetic materials. Hundreds if not thousands of genetic pathways are involved in aging processes. No supplement or substance I know of “cures” aging according to any theory. Instead, it appears that multiple approaches are required to address any of the underlying causes of aging.

The approach I take is use of multiple supplements with different but overlapping and synergistic affects. Most of the supplements I discuss here are pluripotent. Again, they have multiple positive effects. I already mentioned how there are many different antioxidants that operate through different cell and body mechanisms and accomplish different results. L-carnosine, for example, is a powerful antioxidant, is an important anti-glycating agent, helps chelate toxic metal molecules out of the body and may help regulate blood glucose levels. Vitamin C has been extensively studies and shown to have powerful effects in many domains including inflammation, glycation, nervous system health, cancer and cardiovascular diseases. Resveratrol is another powerful antioxidant that works on a genetic level to suppress tumor formation. It generates a chain of genetic-biochemial events involving the SIR-1 gene that may well enable 20% to 30% life extension in humans since it does so in many more primitive species.[6]

Pluripotency of these substances is more the rule than the exception. A few decades back Vitamin D was seen to be useful mainly for bone maintenance for those deprived of sunlight. The medical establishment sternly warned that any daily dose over 400iu could be seriously toxic. It was not thought of in terms of cancer prevention. Today there are over 80 population and laboratory studies indicating that vitamin D can reduce incidences of and mortality due to multiple kinds of cancer with reductions of 50% or more in some cases. The biological impact of this substance is far from simple; it activates 200 or more human genes and has differential affects in regulating cancer cells with respect to cell proliferation, apoptosis and differentiation. It also regulates angiogenesis. Several studies of nursing home and residential care residents show that people taking vitamin D supplements suffer fewer falls – the reduction being between 23% to 53%. See the blog entry Vitamin D - don't fall for it. And I have already mentioned Vitamin D’s role with respect to reducing heart disease fatalities. Daily doses of 1,000 or 2,000iu are now thought to be harmless and often recommended for older people.

I repeat that the other side of pluripotency is that no one of the supplements is by itself a magic bullet cure for any specific disease of old age.[7] The firewall substances can work through known biological and genetic mechanisms, exercise important positive effects, and improve the probabilities of positive outcomes.  Causes and diseases of old age are very complex and work through many pathways. A breast cancer may involve modification or changed activity of 1,000 genes or more. Recent research shows that if one of the pathways essential to a kind of cancer is blocked by a drug, the cancer cells will simply modify themselves to use an alternative pathway. Simultaneous attacks on multiple biochemical pathways appear to be necessary to stop certain cancers. Many of the seemingly-simple individual herbal substances in the combined firewall act in multiple complex ways. A study, for example, shows that ashwagandha kills cancer cells via at least five different pathways: p53 signaling, GM-CFS signaling, death receptor signaling, apoptosis signaling and the G2-M DNA damage regulation pathway. Likewise, combining several substances with varied forms of action, the combined firewall offers simultaneous attacks on multiple pathways related to cancer and the other “causes” of aging.

The substances in the combined firewall are discussed in various contexts in a number of my blog entries, for example in Diabetes Part 2: Lifestyle, dietary and supplement interventions and in Alzheimers disease studies validate anti-aging firewalls suggestions.

Underlying the firewall concept is the idea of creating a multiplicity of defenses against multiple causes of aging taking advantage of multiple biochemical and bio-genetic strategies. Some substances in the combined firewall can produce somewhat similar results. But they can work in different ways and also produce some strikingly different results. For example, curcumin, resveratrol and epigallocatechin gallate (ECGC, an active ingredient in green tea) are each anti-oxidants, anti-inflammatories and have cancer-fighting properties. Yet, a recent study shows that resveratrol is protective of colon epithelial cells from harm created by the bile salt deoxycholate but curcumin and EGCG are ineffective in this regard.

Controversy crops up from time to time in the popular press about the safety of taking large doses of certain vitamins. I do not suggest taking very large doses of any substance. The general approach I take is to utilize normal doses of multiple supplements in a firewall rather than mega-doses of one or two supplements. The reasons for this are safety as well as enhanced effectiveness. The doses I suggest are generally within the range of ordinary supplement usage and are generally regarded to be safe for people with normal medical histories. However, taking certain of the supplements could be inadvisable for people with particular medical conditions, taking particular drugs, or possessing unusual gene variations. For example, it many be inadvisable for people taking immune system suppressants to also take astragalus or astragaloside IV supplements. Dietary supplements are not tightly regulated in the US and may vary widely in purity and quality. It is important to use reputable suppliers with high established quality standards. And many herbal and other supplements may produce side effects under particular circumstances. Responsibility for safety of supplement use must rest with the reader and his or her medical advisers, not with the author or any publisher of this document.

I can't explain all the known benefits and issues associated with each supplement here; that would require a much longer paper and more knowledge than I have. And, for several of the supplements, the benefits as well as the underlying biochemical mechanisms are not yet completely understood. However, I do want to mention that many of the supplements are known to be powerfully synergistic with one another. Coenzyme Q-10, for example, can recycle reduced forms of vitamin C and E, helping maintain the levels of those antioxidants in the body under conditions of stress. Another example demonstrated in animal studies is that when Carnosine and alpha-tocopherol are co-administered, the result is significant amplification of the therapeutic biopotency of both. In one study, a combination of alpha-tocopherol and Carnosine was administered to rabbits with atherosclerosis induced by feeding them polyunsaturated fatty acids. A 10-fold decrease of the impaired aortic area was observed. A recent research report indicates that, even at low concentration, lycopene and EPA synergistically inhibits the growth of human colon cancer HT-29 cells. Resveratrol and quercetin are chemical cousins which in combination prevent the growth of or facilitate the apoptosis of 3T3-L1 fat cells.

Do any of the supplement’s interfere with each other so as to create a dangerous combination? Not to my knowledge, and such situations are not described in any of the studies I have encountered. This is always a possibility, however, particularly for people with unusual gene variations.[8]

How effective are the firewalls I am proposing? I don't know. There is published reseaarch evidence to support all of my assertions.

Research basis for the firewalls

The firewall suggestions, both for following certain lifestyle patterns and for taking certain supplements, are based on scientific research even though some of them are also supported by folk lore or conventional wisdom. But what is the nature of this scientific research? It can be of several different kinds, including:

1. Macroscopic studies of large populations. These studies involve looking for correlations among selected factors. An example is a study of centenarians on Okinawa, an island where an unusual number of people live a long time. This study of some 900 centenarians, their families and control groups helped identify specific genes and gene polymorphisms that appear to contribute to longevity as well as contributing lifestyle factors, including eating relatively few calories, exercising and not smoking or consuming alcohol. And of course in Okinawa people eat lots of fish and drink green tea. These studies can reveal interesting correlations and clues. For example, the Okinawa study established that the centenarians studied have genetic polymorphisms that place them at lower risk for inflammatory and autoimmune diseases.

2. Large population cohort studies. These are studies that follow cohorts of thousands, tens of thousands or even hundreds of thousands of people over 10-20 or longer year periods, like the Woman’s Health Initiative or the Framingham Heart Study or the Bogalusa Heart Study. Again, they look for correlations such as the effect of smoking or being overweight on cancer incidence or longevity. These studies have been particularly useful for establishing the validity of conventional wisdom as related to longevity, such as clearly documenting the effect of having a positive mental attitude on longevity.

3. Controlled clinical trials. These are carefully controlled double-blind studies that proceed in well-defined phases, i.e. safety, dosage and then effectiveness. They are typically pursued for drug certification and may involve anywhere from a few dozen to thousands of carefully selected people over a test periods of several months for the final phase. These studies are usually quite narrowly focused and yield limited information with respect to longevity. For example, a list of clinical trials for patients diagnosed with gliablastoma, an incurable brain disease, can be found here. These trials are very specific with respect to substance being tested, patient conditions and their relationship to other therapies. Clinical trials typically cost tens or hundreds of millions of dollars so there is no incentive for a drug company to study a promising natural substance that is in the public domain. Also, for longevity purposes, a six-month study is not likely to tell much. If we wanted to test some kind of longevity concoction that we thought would double human life-spans, a clinical trial would have to be run for 40-100 years to yield definitive results.

4. Animal experiments. Mice and rats are genetically very similar to humans but live only 2-3 years, so are excellent subjects for longevity-related experiments. The studies can be quite technical and very narrowly focused. Here is an example relevant to the cell nuclear factor NF-kappaB known to be relevant to human longevity: Maintenance of NF-κB Activation in T-Lymphocytes and a Naive T-Cell Population in Autoimmune-Prone (NZB/NZW)F1 Mice by Feeding a Food-Restricted Diet Enriched with n-3 Fatty Acids. In combination, though, these studies can yield important insight. We know of several approaches that can extend the normal lifespan of mice by 30% to 50% We are not sure how many of these approaches will scale-up to work for humans but these experiments are providing valuable clues and are a source of optimism for longevity aficionados like me.

5. In-vitro and in-vivo studies of cell populations. There is a great number of experimental studies going on that look at specific cell populations under particular conditions that that have a bearing on longevity. For example, many such studies look at neurogenesis and adult stem cell differentiation as impacted by specific gene activation cascades and particular proteins, or as stimulated by certain dietary substances. These studies can yield specific nuggets of insight such as the roles of key proteins and activation factors like INK4a, P-53, and NF-kappaB. Again, there are very many of these studies and they can be quite technical each yielding a single piece of the immense longevity puzzle. An example related to eating pigmented fruits is A dietary anthocyanidin delphinidin induces apoptosis of human prostate cancer PC3 cells in vitro and in vivo: involvement of nuclear factor-kappaB signaling.

6. Synthesis and review studies. These are studies that consider results together from possibly many experiments and look at them in terms of the powerful forefront areas of genetics, cell signaling cascades, gene activation, genomics and epigenomics. They also draw on knowledge from related areas, such as computational genomics, epigenomic and protein-folding databases. Some of these studies are starting to link gene expression factors to longevity, such as described in SIRT6 Links Histone H3 Lysine 9 Deacetylation to NF- B-Dependent Gene Expression and Organismal Life Span. We have identified various cell signaling cascades directly related to longevity such as the Insulin Growth Factor 1 axis. This axis seems to be the one that is involved in achieving longevity via calorie restriction. And it also seems to be activated by taking the supplement resveratrol.

All the actions and supplements in the anti-aging firewalls are based on one or more of these kinds of research. Most are supported by several of these kinds of research and, for a few firewall elements, supporting research exists on all of the above levels. For example, the value of green tea as a cancer preventative is established on all of the above levels as are the actions of Vitamin C and the value of regular hard exercise for longevity in general.

It is clear that radical life extension — to beyond age 110 — must depend on knowledge associated with the newer and more sophisticated ongoing studies in epigenetics, molecular biology, and medical research. Research suggests that certain substances already in the anti-aging regimen may act powerfully toward this end, but what they can actually do for human life extension will not be clearly known for many years. These substances include:

- Use of r-alpha lipoic acid and acetyl-l-carnitine to address cell mitochondrial longevity and inhibit unwanted cell apoptosis (self-destruction).

- Use of resveratrol or resveratrol homologs to activate the SIRT1 and FOXO3 “longevity” genetic pathway, the pathway known to confer life extension due to calorie restriction.

- Use of astragaloside IV or cycloastragenol to activate telomerase expression in body cells, possibly immortalizing these cells and conferring longevity to the associated organs..

- Use of combinations of green tea, curcumin, and other phyto-substances for their powerful cancer-preventative effects and cardiovascular benefits that operate through genetic mechanisms

Extensive additional research will be required to test, refine and improve the firewalls, perhaps requiring another sixty years before they become optimal. A real clinical trial of the life extending capabilities of each of the firewalls would require many years and testing the entire program would require over more than 100 years. Personally, I can't wait. Besides, what is in the best firewalls will continue to evolve with time. The state of our knowledge with respect to the topics in this paper is rapidly shifting to where it is increasingly based on hard science. A 1956 computer was vastly superior to a 1950 computer and a 1960 computer was vastly better yet. This pattern of improvement continues until today – almost 60 years later. The same is true today in the biotech-longevity field where we are just at the start of the corresponding 60-year development period. Every week seems to reveal one or more new studies that bring new insight to the foreground. Back in 1956 for scientific and business purposes, having, a 1956 computer was vastly superior to having none at all. The philosophy of this paper is that right now for health and anti-aging purposes, a 2010 firewall regime is vastly better than none at all.

Tests are becoming available which will allow individuals to test their genes for variations which point to susceptibility to a wide variety of diseases. As time progresses, knowledge grows and genetic profiling becomes more widely available, more people will know they possess gene mutations which increase their susceptibility to any of a number of age-related conditions such as Alzheimer’s disease and diabetes. I expect it will also become possible to modify the firewalls for such individuals to give them more focused protection. Both medicine and health-maintenance will become more individualized.

Are my 135 pills a day an overkill? Perhaps. Perhaps I could eliminate taking 20% of them. Perhaps. The issue is that I don't know which 20%. How many more years of life span will these firewalls buy you or me? Again, I don't know. Part of the answer depends on your genetic makeup, age, lifestyle and history of course. But that ducks the question. Even if you were an “average” 65 year-old I would not know. Personally at the age of 80, I am looking for another 140 good years. Clearly this will require new breakthroughs and my hope and expectation is that these constantly improving firewalls will keep me going until these breakthroughs come along.

Finally, I need mention that a few of the supplements I take are primarily for specific conditions, like glucosamine to ward off osteo-arthritis and stinging nettle and saw palmetto for prostate health. These and others are interim firewall components, useful until substances that address the underlying issues become available. For example, I take pregnenalone and DHEA supplements because levels of these and their daughter hormones plunge down with age. I do not now know how to address the more root issue: why these hormones drop so steeply with age. If a new bio-genetics approach is found that keeps the level of natural production of these substances up despite age, then I could discontinue those hormone supplements.

TABLE I – SUPPLEMENTS IN COMBINED FIREWALLS

Version March 31, 2010

Vitamin C - 3gm	2gm morning, 1gm afternoon/eve
Vitamin D-3 – 2000 IU	Twice daily
Probiotic - 8 major strains	Morning
Curcumin extract – 1160 mg	Twice daily
B-50 complex - (50 mg for most)	Morning
Vitamin B-12 - 500mcg	Once daily
Benfotiamine – 80mg	Twice daily
Vitamin B-6 – 100mg	Twice daily
Pantothenic acid – 500mg	Twice daily
Mixed carotenes	Once daily
Folic acid – 900mcg	Once daily
Chelated copper 2.5mg	Once daily
Potassium gluconate 100mg	Once daily
Calcium (as carbonate, aspartate, citrate) 1 Gm	Twice daily
Magnesium (as oxide, aspartate, gluconate) – 500mg	Twice daily
Zink (as oxide, aspartate, gluconate) – 30mg	Twice daily
Selenium – 200 mcg	Once daily
R-alpha-lipoic acid 200 mg	Twice daily
Acetyl-l-carnitine 500mg	Twice daily
L-carnosine - 500mg	Before breakfast, before bed
Co-enzyme Q-10 – 150mg	Twice daily
Pycnogenol - 100 mg	Twice daily
Bromelain – 250mg	Twice daily
Lycopene – 10mg	Once daily
Quercetin – 500mg	Twice daily
Ginkgo Biloba extract (stand. to contain 24% flavone glycosides and 6% terpene lactones) - 60 mg	Once daily
Saw palmetto (stand. to 85-95% fatty acids) – 200mg	Twice daily
Ashwagandah extract (stand. to 1.5% withanolides) - 470mg	Twice daily
Boswellia Seratta (stand. to 70% organic acids and 20% boswellic acid)extract - 300mg	Twice daily
Astragalus extract (stand. 0.5% astragalosides – .25gm	Twice daily
Extract containing 10 mg cycloastragenoll	One daily, taken 6 hours after and 4 hours before other supplements
Olive leaf extract (stand.to 20% oleuropein) - 750mg	Twice daily
Green tea extract (stand. to 60% polyphenols) – 1.5gm	Morning
OPC grape seed extract (stand. 120 seeds/mg)	Twice daily
Omega-3 oils: DHA - 400mg; EPA - 800mg	Two morning; one evening
Resveratrol extract (stand. 325mg of trans-resveratrol)	Twice daily
Avena Sativa 19:1 extract – 1,150mg	Twice daily
Allicin - 1gm	Twice daily
Stinging Nettle Each capsule supplies 250 mg of stand. nettle extract (1% silicic acid) and 270 mg of powdered root.	Twice daily
L-theanine 100mg	Twice daily
Phosphatidylcholine – 385mg	Morning
Lecithin – 1200mg	Morning
Glucosamine sulfate	Twice daily
Piracetam - 800 mg	Morning
Meclofenoxate (centrophenoxine) - 500mg	Morning
DHEA 50mg	Morning
Pregnenalone - 60mg	Morning
Melatonin - 3mg	Before bedtime

VI. ADDITIONAL CANDIDATE THEORIES OF AGING

As of March 31, 2010, over two years have elapsed since the original formulation of this treatise. During that period, several additional molecular phenomena and pathways that relate to aging have come to my attention. These have been identified and to some extent discussed in the blog that corresponds to this treatise or in a note in the treatise itself. Some of these suggests an additional candidate theory for what drives aging. I do not wish to identify these yet as theories of aging in this treatise because they are relatively new to me at least, and sometimes sketchy. Much is still to be learned about each of them. Some of these candidate theories may eventually be subsumed under one or more of the 14 theories already laid out above. Effective anti-aging firewall interventions against the aging processes described by the first five of these candidate theories either do not exist now or are unsafe for non-research use. I describe and comment on each of those candidate theories here: 15. Incorrect protein folding, 16. Accumulation of progerin, 17. Gene mutations leading to hellicase abnormalities, 18 Increasing mTOR signalling, 19. Declining hypoxic response, 20. Epigenomic changes in DNA methylation and histone actetylation, and 20. Micronutrient triage with aging. In May 2009, I integrated one such candidate theory 20. Epigenomic changes in DNA methylation and histone actetylation into the discussion of the 13th main theory of aging Programmed epigenomic changes.

15. Incorrect protein folding

One candidate for an additional theory of aging in this Anti-Aging Firewalls treatise is Misfoldings of proteins. The basic notion is that stress often leads to the misfolding of proteins, a process that can accelerate with age creating dysfunctional conditions and vulnerability to a number of diseases. Misfolded proteins cannot perform their intended functions and can create active mischief. This is a relatively new area of science and is to a large extent still unexplored.  Here is a simplified preview.

Biology gets things done using proteins, which are encoded by various genes. Proteins are the building blocks of our body tissues; they can also be enzymes, hormones, antibodies or be intercellular and extracellular signaling molecules. Proteins can be very large molecules, consisting of 20,000 or more amino acid units. Each protein begins through tiny ribosomes in the cell cytoplasm reading instructions from messenger RNA which comes from the cell nucleus. The ribosomes act to link up amino acids in a long linear chain (polypeptide) in a process called translation. Each amino acid in the chain attracts or repels the other amino acids in a complex electrochemical way, soon causing the protein to fold up naturally into a characteristic 3-dimensional structure for that protein – a sort of automatic origami folding process. The folding may take a microsecond or up to a minute. In the process new electron bonds are formed among the amino acids determining many of the chemical and biological properties of the protein. The shape of the protein helps determine its functionality.

The way the folding process takes place and the ultimate structure may also depend on surrounding conditions in the cell, and folded proteins can become parts of larger macromolecular structures. Proteins interact 3-dimensionlly with other proteins and the structures can fit into each other like locks and keys. Many proteins may have to unfold to do their work. Whether and how proteins are folded or unfolded affects their capabilities to perform a number of important functions, including their ability to activate genes or function as enzymes or antibodies. Protein folding and unfolding are involved in a number of critical cellular processes related to aging like apoptosis, stem cell differentiation and telomerase acting to extend telomeres. A simple introduction to the subject of protein folding as it relates to aging can be found here.

Lots can go wrong in the folding and unfolding processes and the building of larger molecular structures. Sometimes proteins can fold improperly, potentially resulting in a number of cancers or devastating neurological and degenerative diseases including Huntington's and Parkinson's disease and cystic fibrosis. Clumps of misfolded proteins are thought to cause the symptoms of Alzheimer's and Mad Cow(BSE) diseases. Self-assembly can go screwy such as in the case of Amyloidosis where proteins abnormally assemble into insoluble fibrils that impair organ function(ref). Benign folded proteins can unfold and refold into deadly types.

The rate of protein misfolding seems to increase with age and misfolded proteins are implicated in many of the major diseases of aging. Cellular machinery exists to get rid of misfolded proteins but doesn’t always work right. A category of proteins called chaperone proteins has evolved, their purpose being to assist in the processes of folding, unfolding, building of larger structures, and repairing folding errors. Chaperones also play other roles such as assisting in the translocation of proteins into organelles. Heat shock proteins are chaperone proteins that work to ensure proper folding processes under heat, oxidative and other forms of stress. It appears that thermodynamic stability is critical to the biology of proteins.

Protein folding is a hot research frontier area, looked at by many as one of the great little-explored mystery areas of molecular biology. The research area is rich in what it may tell us about signal transduction mechanisms, intracellular transport, turnover of normal and misfolded proteins, cell differentiation and development, malignant transformation, misfolding diseases and aging. Much of the study of protein folding is currently being done in the contexts of neurological diseases and cancers, two of the aging-theory areas covered here. But the research is likely also to be relevant to aging in several other ways. Stress, for example, particularly heat and possibly oxidative stress, can impair the proper folding of some proteins. Unfolded proteins in the endoplasmic reticulum appear to generate reactive oxygen species which lead to cell apoptosis; antioxidants can both reduce misfolding and enhance cell survival(ref). Stress-induced interference of protein folding may be responsible for some of the pro-apoptotic effects of resveratrol on colon cancers(ref). Telomerase expression is an aging-related area where there is active ongoing research related to the folding structures of telomerase components(ref)(ref). And I suspect protein folding disorders may be related to the accumulation of lipofusin and AGEs.

While it is known that protein geometry and the folding and unfolding processes are essential for biological processes to take place, how this works in specific instances is still largely unknown. Sophisticated tools are used in protein folding research like the Atomic Force Microscope which can exercise forces which unfold proteins(ref). Another new technology for studying protein unfolding is called pulse proteolysis. One promising approach has been based on a predictive computer program called Rosetta which combines data from nuclear magnetic resonance imaging and X-ray diffraction imaging to identify possible protein molecule structures(ref). Protein folding is too complex a process to predict without intense use of computer modeling. Determining the various ways proteins can fold and the kinetics of folding is a daunting computational problem. Even the largest supercomputer cannot analyze all the possible geometrical configurations for a large protein molecule in a reasonable amount of time. A protein may fold in a microsecond but it could require 30 years of CPU time to simulate that event thoroughly. A distributed computing initiative has been launched to tackle this task of studying protein folding and misfolding for specific proteins. The idea is to get thousands or tens of thousands of people to lend their PCs to work on the problem when their PCs would otherwise be idle. You can sign up to participate in that initiative here. An increasing number of papers on protein folding are being given at conferences and new research techniques are being reported(ref). So we can expect to hear a lot more about protein folding in the coming months and years.

At the moment it is difficult for me to identify additional specific knowledge derived from the area of protein folding/unfolding that can be translated into an anti-aging firewall, though there are a few initial hints. For that reason, I am not yet integrated Misfoldings of proteins into this paper as a theory of aging. However, I am on the lookout for such knowledge and expect to report back on this topic as I learn more

16. Accumulation of progerin

The aging mechanism under consideration here is that manifest in HGPS, standing for Hutchinson-Gilford progeria syndrome, an extremely rare but well-studied genetic disease. Young children born with HGPS seem to age at an extraordinary rate, exhibit many of the symptoms of old age, become wrinkled and bald, are particularly vulnerable to cardiovascular diseases and usually die of a cardiovascular disease of old age by the age of 14.  Up until about five years ago neither the cause of the disease nor a cure were in sight.  Then a chain of exciting research developments emerged indentifying not only cause and possible cure but also what might amount to a new theory of normal aging.  The developments are complex and the puzzle is still far from complete.  I attempt to summarize them here in simple language and speculate on the implications involved. 

1.  HGPS is caused by a mutation in the LMNA gene which is responsible for making lamin proteins which provide “scaffolding (supporting) components of the nuclear envelope, the structure that surrounds the nucleus in cells.”  The mutation produces a lamin that is “farnesylated but cannot be further processed to mature lamin A.(ref)”  That mutant farnesylated lamin is called progerin.  (Farnesylation is a post-translational chemical modification of a protein involving addition of a farnesyl group.) In progerin, a DNA sequence of 50 amino acids which would normally appear in the lamin is spliced out.

2. Progerin targets itself to the nuclear envelope of a cell, “where it interferes with the integrity of the nuclear envelope and causes misshapen cell nuclei(ref).” There is strong reason to believe it is responsible for the symptoms of HGPS(ref).

3. An obvious research idea was to see what could happen if the farnesylation of progerin is inhibited.  An exciting development was the discovery that, treating cells misshaped by the expression of progerin, inhibiting farnesylation with a farnesyltransferase inhibitor (FTI) could restore their normal cell shapes(ref,ref,ref,ref).  FTIs block the attachment of the farnesyl chemical group onto progerin. FTIs are a class of recently-developed anti-cancer drugs.

4. Sure enough and better yet, using the FTI  drug Tipifarnib (Zarnestra) in a progeria mouse model it was possible to prevent both the onset and late progression of cardiovascular disease(ref). This led to a hope that a cure for human HGPS might be based on use of an FTI.

5. A clinical trial was launched in May 2007 to test FTI therapy in HGPS patients(ref).  It was difficult finding patients because of the rarity of the disease.  Twenty eight children from 16 countries are participating. The trial is scheduled for completion in October 2009 with reporting in 2010.

6.   Progerin appears also to play possibly important similar roles in normal aging.  Biochemical studies sugest that progerin may generate similar impacts in HGPS cells and aged normal cells and possibly a common molecular mechanism might underlie HGPS-type aging and normal physiological ageing. “Cell nuclei from old individuals acquire defects similar to those of HGPS patient cells, including changes in histone modifications and increased DNA damage.  Age-related nuclear defects are caused by sporadic use, in healthy individuals, of the same cryptic splice site in lamin A (progerin) whose constitutive activation causes HGPS. Inhibition of this splice site reverses the nuclear defects associated with aging(ref).”

7. Supporting this idea, recent research indicates that progerin builds up in normal cells with age.  A powerful new technique has been developed for measuring the expression of the progeria gene. A Swedish research group has found that both normal and progeria cells make larger and larger amounts of progerin RNA as they age(ref).

8.   Supporting the idea of progerin accelerating aging even further, research indicates that progerin creates all kinds of downstream biomolecular signaling mischief, including the introduction of errors in the normal differentiation of stem cells.  Progerin interferes with cell division in both HGPS and normal cells(ref).  In one key study(ref), the presence of progerin produced a profound impact on renewal and differentiation of adult mesenchymal stem cells, affecting the rates at which they mature into different tissues. “Our results support a model in which accelerated ageing in HGPS patients, and possibly also physiological ageing, is the result of adult stem cell dysfunction and progressive deterioration of tissue functions.”  

  There are