Fifteen years ago, Aubrey de Grey organized the first SENS roundtable–Strategies for Engineering Negligble Senescence.  It was a small group of out-of-the-box thinkers, heretics who talked about attacking head-on the idea that aging is just part of the human condition, looking for medical (and beyond-medical) treatments that would restore strength, stamina, and alertness, and lower the risk of all the diseases of old age at once.

There followed five more SENS conferences in Cambridge, UK.  Now, SENS HQ has moved to Silicon Valley the series has been absorbed as a summer Rejuvenation Biotech conference in California.

This is the mainstreaming of anti-aging science, the product of many long years of work and relationship-building, largely by Aubrey himself.  As Joni Mitchell wisely warns, “Something’s lost and something’s gained…our dreams have lost their grandeur coming true.”  There is a lot more money, a lot more data, well-established people and funders are involved.  But there is less daring, out-of-the-box risk-taking than in the past, and my personal judgment is that we are still at a stage of understanding where high-risk science is essential.

At one point, a young man posed a question in a session devoted to cancer strategies.  The most common cancers attract the most funding, he said, and there has been little progress over the years in survival percentages in these cases.  Meanwhile, there has been dramatic progress in rare cancers, though they are the province of fringe research with little mainstream funding.  Perhaps there is an inverse correlation between funding and scientific progress.  Perhaps funding distortions favor repeat funding of long-term projects, with a resulting bias toward failed ideas.  Perhaps funding makes scientists more conservative, and impedes discovery.  This was a perspective that no one could digest, and audience and speaker moved on with embarrassed laughter.  

At the end of this page is the most exciting thing I learned at the conference, which is also the most far-flung and likely to be an artifact.

 

Alzheimer’s Trial using Infusion of Blood Plasma from Young Donors

Tony Wyss-Coray of Stanford has what I consider the boldest and most promising program for rejuvenation today.  He discovered last year that mice given 8 infusions of 0.1 ml blood plasma from a young mouse showed dramatic improvements in cognitive performance.  (This is the equivalent of about ½ pint of blood per infusion in human scale.)  Tony told us that there was an unpublished experiment in which similar benefits were achieved with blood from young humans infused into older mice.  The cognitive improvements last at least a few weeks, but were not tested beyond that time frame.

Take a moment to appreciate how unexpected this was.  Even for those of us who are enthusiastic about the ability of blood factors to reprogram the body’s age, we expected that many repeated treatments would be needed, and that it would be necessary to remove pro-inflammatory factors from old blood as well as adding pro-growth factors from young blood.  Most blood factors are constantly being generated and destroyed, so their lifetime in the bloodstream is only a few hours or even minutes.  It was beyond optimistic to think that so short a course of treatment would have a measurable effect.

The result was so promising that Wyss-Coray is leapfrogging over the animal testing phase.  He has formed a for-profit spinoff, proceding right to clinical trials.  (This is possible because plasma transfusion is already a mature technology, long approved for safety in other contexts.)

 

Thymus Regeneration

Georg Hollander presented a cogent and enlightening exegesis of the thymus, from basic function to ongoing projects.  The thymus is a small gland under the breastbone that is responsible for a crucial function of the immune system:  traing white blood cells (T-cells) to distinguish between self and other, so they can consistently attack the latter and spare the former.  In adulthood, the thymus atrophies (“thymic involution”), and in old age there is almost no thymus left, with the disastrous result that T-cells not only fail to protect our bodies from invaders, but treat our bodies as the enemy, leading to autoimmunity.  The training is performed by web-like epithelial cells, shaped like crumpled blankets, each epithelial cell in contact with up to 60 developing T-cells.  Epithelial cells must express every single protein in the genome, and there is a transcription factor called AIRE that binds to DNA, promoting “promiscuous expression.”  Curiously, AIRE works best for genes that are normally turned off by methylation or acetylation.  15% of genes are expressed only in the presence of AIRE.  There are micro-RNAs that are also necessary for promiscuous expression of all genes.  

Hollander has been working on the hypothesis that each epithelial cell succeeds in programming only a random subset of the genome, so if you have fewer epithelial cells late in life, the cells collectively will not express every single gene in the body; there will be holes in the set of all genes represented in the thymus, and as a result there will be autoimmunity.  He said we need a minimum 200-300 epithelial cells for a fully-functioning thymus that protects the body against itself.

At Wake Forest Inst, John Jackson is working on growing epithelial cells in a petri dish, then forming them on a scaffold, integrating blood vessels (vascularization) and structural (stromal) cells.  His intern Blake Johnson made remarkable progress in a single summer toward creating a functional mouse thymus.  Mice (like other small animals) have much larger thymi in relation to body size; and (like humans), they lose most of their thymic volume over their short lifetimes, with the result that their immune systems are disabled and they are vulnerable especially to cancer.

FOXN1 is a transcription factor that may be a key to thymic reactivation.  Last year, a Scottish group announced growing a fully-functional thymus and transplanting it into a mouse.  A Pittsburgh group is working on similar techniques.  Greg Fahy of 21st Century Medicine is conducting a tiny clinical trial in the coming year, using growth hormone and other blood factors to regrow the thymus in people 50-65 yo.  (Enrollment is closed; they are not seeking test subjects.)

 

Two paths to longevity
(Dataheads can skip this and the following section. They are just philosophy.)

Very broadly, there are two approaches to anti-aging medicine, which might be called “bioengineering” and “endocrinology”.  The question is, how much of the change that takes place with age can the body reverse with its internal resources, given the appropriate chemical signals (that’s endocrinology)?  And how much remains that must be rebuilt or replaced with prosthetics (bioengineering)?  From the beginning, SENS has emphasized the bioengineering approach–its middle name is “engineering”.  I am more optimistic about what the body might be able to do on its own, if only we can master its biochemical language.  

Significant advances have been made in bioengineering in the 15 year history of SENS.  A prosthetic limb no longer needs to be a peg leg, but can be designed to respond to neural signals.  Prosthetic eyes and ears have come down from the clouds into the realm of the feasible.  The first organs grown cell-by-cell on scaffolds in the lab have been re-implanted successfully in human patients.

But even more stunning and promising breakthroughs have appeared in the realm of chemical signaling.  In 2000, before the Bush Ban, all stem cell research depended on embryonic stem cells harvested from foetal tissue; but turning muscle or skin cells back into stem cells has turned out to be surprisingly easy (though the process is still being refined).  “Epigenetics” was an abstract noun in 2000, and it is now the fastest-growing area of biological science.  Epigenetic signaling may be the organizing principle of whole-body aging [ref, ref, ref].  Signal proteins have been identified that turn on whole systems of genes that retard aging.  Better yet, pathways that promote inflammation (e.g. TGF-β, NFkB) can be blocked, while some blood factors (e.g. FOXn1, oxytocin) turn on regenerative pathways, with the promise of rejuvenation.  Steve Horvath has pioneered a bioinformatic approach to identifying the epigenetic differences between old and young humans.

 

Broad strategies

Business is averse to risk.  Science is all about exploring the unknown.  It’s not exactly a match made in heaven.

Chas Bountra is deeply tied to the establishment, but radical in his own way.  He is a veteran of many years as head of research at Glaxo Smithkline, and now directs the Structural Genomics Unit at Oxford.  His focus is Alzheimer’s Disease, and tells us why:  We have a basic understanding of cancer, stroke and heart disease, and are making steady, incremental progress toward prevention and higher survival rates.  If current trends continue, dementia will be the scourge of the next generation, exacting an unaffordable social cost as patients survive for years, unable to contribute to society, to care for themselves or even to enjoy social interactions with others.

He is interested in “novel targets”.  He will not consider amyloid beta or Tau protein aggregates because, “we have spent tens of billions of dollars researching A-beta plaques and we still can’t Bountra makes an impassioned plea for open source researching.  He boasts of doing research that drug companies shun as too risky, and having succeeded in identifying more than 40 new targets that drug manufacturers have pursued and brought to the market.  His research unit publishes all data, takes no patents, and shares all ideas in academic journals.   His model: Universities take all the risk, using public monies; pharmaceutical giants make all the profits.  (Big Pharma then uses its considerable leverage in lobbying Congress to increase funding for biochemical research.)

For a commie like me, this model is tainted with corporate welfare, but while I choke on the social injustice, I admit that it is practical and effective in today’s political environment.

 

Oldest Aging Scientist Still Active

That title probably goes to George Martin, at 88 still deeply thoughtful and open to new ideas in his U Washington lab. I visited George a week earlier, on my way to San Francisco.  Len Hayflick, 87, works at UCSF.   At 86, Bruce Ames is still active and doing good work.  After the conference, I was privileged to visit his lab in Children’s Hospital Oakland Research Institute (CHORI).  Ames has been doing innovative biochemistry since the 1960s, and by now has persevered to see some of his heresies absorbed into the canon of public health.  After a 32-year career at UC Berkeley, he moved to emeritus status and opened his present lab in 2000.   

In 1972, Ames launched his career by investing a quick and easy lab test for mutaogenicity (and presumptive carcinogenicity) that has saved millions of dollars and countless rabbits and mice.  

In the 1980s, Ames was an early influence on my diet and helped form my understanding of aging.  In that era, we all thought about buildup of toxins and cumulative effect of carcinogens.  Ames was at the forefront, ranking carcinogens by a scheme he called HERP, which took proper account of potency and average public exposure.  The conclusion that surprised him and alienated many advocates of natural medicine was that natural carcinogens are common in the foods we eat, overwhelming the risk from pesticides and preservatives for which we were seeking tighter regulation.  Always an evolutionary thinker, Ames headed off the argument that we might be evolved to deal with natural carcinogens but not manufactured carcinogens, demonstrating that diets and lifespans of our hominid forbears made that conclusion unsupportable.

Ames was one of an elite group at the first SENS roundtable discussion in 2000, forerunner of the RB2015 conference that I attended last week.

Today, Ames argues that dozens of micronutrients are essential for both day-to-day metabolism and for long-term health.  When any of these micronutrients are in short supply, the body prioritizes the former, and the latter is shortchanged, with consequences for longevity.

In Bruce’s lab, I met Rhonda Patrick, a dynamic young post-doc who both does innovative nutritional science and has a uniquely nerdy and well-informed video blog, FoundMyFitness.com of health advice, broadcasting biochemistry, nutrition and metabolism for the masses.  

I can’t resist noting how pleased I was to find support in Bruce’s lab for my contrarian idea that aging is controlled in part by an evolved genetic program.

 

Metformin Update

I have been an advocate of metformin for everyone, and enthusiastic about Nir Barzilai’s trial of metformin as an anti-aging drug.  Last week, I learned from Brian Hanley that metformin has a dark side, to wit, a statistical association with higher frequency of Alzheimer’s disease [ref, ref].  There is a biochemical mechanism that makes the epidemiology more compelling.  B12 supplementation may mitigate the risk.

Other studies [ref, ref]  have found that diabetes patients have elevated risk of dementia, and that that risk is reduced when they take metformin.  So it’s fair to say that there is contradictory evidence, and the direction of the effect may depend on individual variation.  Here is a balanced view of both sides.

A reader of this blog, George Goldsmith has written to me that berberine is a good herbal substitute for metformin.  Everything we know about berberine looks really good–it is an anti-inflammatory as well as helping preserve insulin sensitivity, acting through the AMPK pathway.  But we have much more experience with metformin, both clinically and in the lab.  Metformin increases life span in mice, and to my knowledge, this test has yet to be performed with berberine.  Magnesium supplements also can help prevent insulin resistance, and there are other good reasons to take magnesium.  

Gynostemma pentaphyllum, sold by LEF under the brand name AMPK Activator, is another herbal alternative to metformin.

 

Telomeres

Bill Andrews was a major sponsor of the conference and a ubiquitous presence, though he did not make a presentation.  Curiously enough, the only spokesperson for telomere biology was Judith Campisi.  While Andrews has taken the position that lengthening telomeres is more than a good thing, possibly a key to reversing aging, Campisi has cautioned us that telomerase is rationed by the body, and there must be a good reason for this.  For two decades, Campisi has been the principal advocate of the thesis that telomeres are permitted to shorten in order to protect us from runaway replication of tumor cells.  

My judgment is that Andrews has it right, and Campisi is clinging to a flawed theory   At this point, overwhelming evidence tells us that short telomeres cause many more cancers than they prevent.  To her credit, Campisi has backed away from the cancer theory which she had so long propounded.   But she has yet to embrace the radical truth that telomere shortening is an evolved mechanism of programmed death (and has been since the dawn of eukaryotic life).  Campisi is a good scientist who knows as much about telomere biology as anyone on the planet; but she has afforded too much deference to the prevailing evolutionary perspective, though it is contradicted by evidence that she can (and does) recite from memory.  So her more recent papers stress the (sometimes) beneficial role of inflammatory signals in promoting wound healing, and she pursues a theory that she hopes will someday explain the devastating consequences of telomere shortening as a necessary price to pay for the signals that call forth repair and renewal.

Meanwhile, flawed evolutionary theory continues to be the principal obstruction that impedes progress toward an effective telomerase activator which, I believe, will add years to our lives.  Neither VC investors nor NIH funders have given this subject the priority it deserves.

 

 

Rejuvenation from an extract of umbilical blood
(Here is the promised most exciting, and most speculative thing I learned.)

Wuyi Kong is a researcher in regenerative medicine who spent 15 years at Stanford before returning to her native China five years ago.  She now has a private for-profit business, incorporated in Silicon Valley and relocated to China, with enough funding from the Chinese government to get tantalizing results, but not enough to do clinical trials.

She describes particles in umbilical blood that confound a basic principle of biology: that every cell comes from another cell.  She calls these medium-size particles NPRCP, for non-plasma RNA-containing particles, and has observed them in electron micrographs, as they agglomerate into stem cells.  

For 15 years, Kong has been filtering these particles from umbilical blood and injecting them intravenously, first into mice and then into humans, with spectacular results.  In her most complete and convincing paper, she damages the kidneys of mice by cutting off blood supply, then demonstrates regrowth of the kidneys after infusion with NPRCPs.  The problematic claim is that NPRCPs are non-living particles, yet they agglomerate to form stem cells, which are then ennucleated with DNA from the recipient mouse.  This is indeed strange science, but isn’t this all the more reason to replicate her experiments?    

Kong claims anecdotal evidence for erasing wrinkles and white hair turned to black.  More substantively, she says patients have improved energy and faster healing.  One semi-comatose patient with advanced AD recovered not just her consciousness but also her short-term memory.

This is the kind of speculative, creative science that I have come to expect at SENS conferences.  Most such reports do not pan out, but some of them lead to spectacularly disruptive technologies.  We can survive with no less.

One species has come to sit atop the biosphere in much of the world, to dominate and transform the world’s ecosystems.  A complex of environmental crises looms, and they can’t count on evolution to change their genetics fast enough to catch their fall.  The crisis will have to be negotiated with social agreements.  Will their political organizations be up to the task of establishing a sustainable culture without a population crash of unthinkable proportions?  In all the history of life on earth, there is no precedent for this situation.

…or maybe there is…maybe it has happened before that a species has encountered the productive limits of a finite planet, and responded with widespread and peaceful cooperation to avoid ecological collapse.

---

 

My main theoretical contribution to the field of aging research has been the Demographic Theory of Aging.  It says that aging evolved in order to level the death rate in good times and hard times, so individuals don’t all die at the same time, risking extinction in periods of famine or epidemic.

The mathematics of populations is about reproduction in proportion to present numbers.  This implies either exponential growth or exponential decline.  Stable ecosystems cannot be built from populations that are growing exponentially or collapsing exponentially; and no animal species can live (for long) without a stable ecosystem. There are two common objections to this simple, straightforward logic.  

The first is that evolution doesn’t work like this.  “Evolution is about one mutation at a time, and either that mutation produces more copies of itself or less copies.”  My response is that this statement is not a law of nature but a hypothesis.  It is a picture painted not by Darwin, but by evolutionary mathematicians of the early 20th century, including R. A. Fisher and J. B. S. Haldane.  Though this particular model of evolution has been the basis of much theory for the last hundred years, the products of evolution demonstrate that group fitness frequently counts as much as individual fitness.

The second is that animal populations can be stabilized by simple feedback.  When there is plenty of grass on the plain, the rabbits increase in number; and when there is not enough grass on the plain, the rabbits starve, and their numbers diminish.  My response is that this process is too violent to produce viable ecosystems.  The problem is that deaths tend to clump together, and populations overshoot so far that they are bound to vanish to extinction.  The rabbits keep eating and reproducing as long as there is grass to eat.  After that final generation of rabbits has eaten the prairie bare, their offspring–far more numerous even than they–are born into a world devoid of grass, and they all die.  

The tool of my art is computer simulation, (and I wish R. A. Fisher had had computers to support his insight).  Computer models show consistently that ecosystems relying on starvation to regulate their populations are subject to violent swings.  In simulations, animal populations will bloom to hundreds of times the level that can be supported in the long run, only to collapse suddenly to extinction.  The same simulations show that aging is able to stabilize this dynamic.  Each individual’s death occurs on an independent schedule, so they don’t die all at once, and extinction is avoided.

In the 19th Century, the Rocky Mountain Locust was a great success in the American Midwest.  Huge clouds of ten trillion locusts covered the sky for miles in every direction.  Locusts fell from the sky and covered the ground, so thick that a man could not walk without crunching them.  Every green leaf was devoured, and the midwest became a dust bowl.  The locusts drove themselves extinct, victims of their own spectacular success.  The last locust was observed in 1902.

Population regulation is an idea that has been considered and decisevly rejected by the mainstream of the evolutionary community.  The consummate British naturalist V. C. Wynne-Edwards published (in 1962) a book about natural, evolved population regulation that was at once the denouement of his life work and the end of his career.  His theory was ridiculed and dismissed, and two generations of evolutionary scientists could not breathe the words “population regulation” or “group selection” for fear they would suffer the same fate.  But these ideas have begun to resurface in the 21st Century, and in fact it is impossible to understand natural ecologies without them.

Stabilizing population dynamics with aging…

The lion cannot chase down a gazelle in the prime of life–not fast enough.  We might imagine a time in the past when some proud, tragic lion evolved enough speed that he could easily catch any gazelle in the herd.  The genes that allowed her to do this enabled her to provide more meat for her offspring, and they flourished and crowded out the slower lions as the lion population grew.  Plentiful food assured that the population of super-lions grew and grew, until the herd of gazelles was diminished, the herd was picked clean, and the lions died all at once.  This race of lions disappeared.  Elsewhere, the lions that were just a little slower continued to live sustainably with their prey.  What we are left with is a productive and stable demographic structure.  Each gazelle matures through the prime of life, runs fast enough to escape its predators, raises a family.  Then with age, the gazelle’s speed begins to lose its edge.  The lions are able to catch the older gazelles that have already replaced themselves, but not the young ones in the prime of life.  This is a stable population dynamic, and it is made possible by aging of the prey.

…and with social behaviors

Like almost all predator birds and mammala, lions use territorial social behaviors to limit their population sizes and protect their prey.  There are a few spectacular fights to the death, but for the most part, the system is maintained through voluntary submission.  One family will hold a territory, and several non-mating individuals may lurk in the wings but not reproduce and not challenge the territory-holder, sacrificing their individual fitness entirely, waiting for an opportunity like a pool of unemployed workers waiting for a job offer.

Carl Safina: Beyond Words

This week I have been reading Carl Safina’s wonderful new book about the inner lives of animals, and the languages and social structures of three groups in particular:  elephants, wolves, and cetaceans.  He is an engaging story-teller, and after hearing one drama after another of intelligent, collective actions, I came to a new appreciation of animal societies.  Because population regulation is the center of my research, I found myself melding Carl’s ideas with my own, and thinking about conscious, communal responses to overpopulation.

 

Elephants and orcas have much in common.  Both orcas and elephants are apex predators, with no natural enemies.  They are also nomadic, traveling huge distances and foraging over great territories.  They use sound in ways that we might find difficult to imagine, communicating over huge distances.  Both elephants and orcas recognize hundreds, perhaps thousands of individuals, their personalities and social relations, and have names for themselves, can call to specific others over distances of many miles.  Both are guided in their migrations by elder matriarchs who accumulate decades’ of experience about feeding prospects in many and widely-dispersed locations.  Leadership in elephant tribes and orca pods is established via an elaborate political system of social relations, supported by communication modalities that a few devoted scientists, studying them for decades, have only begun to decode.

Because they live much longer than the species on which they depend, their demography must be tuned to plan ahead, or else they are in danger of devastating the species on which they depend for food.  A bloom in the orca population could wipe out salmon, so that the salmon would not recover for a long time; elephants range over many thousands of square miles, and can devastate the foilage in a region because of their prodigious demand for food.

I learned that orcas divide into two cultures.  Some orcas eat fish but not mammals; others eat mammals but not fish.  Both are highly social, and are extremely friendly, gentle, playful and careful in encouters with humans.  Fish-eating whale pods might meet other pods of fish-eating whales and greet them as old friends, talking and touching.  Likewise with mammal-eating whales.  But fish-eating and mammal-eating clans ignore one another utterly.  They overlap in territory, but they do not interact.  They don’t fight, and they don’t talk.  They swim right past one another.

Warning – the rest of this column is my own speculation, and is not established or tested science.  My theory fits the facts, but it is out on the edge.

A species may gradually evolve population regulation built into its life plan, co-evolved within an ecosystem.  This is a long, slow process.  But when a species becomes social, it may learn to hunt with suddenly far greater efficiency than when individuals were hunting separately.  Social learning is much faster than the “genetic learning” that is accomplished via natural selection.  The genes don’t have time to catch up.  So when a species of animals learns to hunt socially, it must also learn to control its population socially.  Through territoriality and other agreements–through culture and communication–the population group must maintain restraint, or it will devastate its food supply and starve to extinction.

I imagine that orcas and elephants each faced this problem many tens of thousands of years ago, perhaps hundreds of thousands of years ago.  They hunt cooperatively with devastating effectiveness.  As they learned to hunt together, they must also have learned some scheme for apportioning the privilege of reproduction, an essentially political process.  Neither species is territorial in the usual sense; they roam over huge, overlapping territories.  Via communication and enforcement systems unknown to science, they have maintained their populations at levels that allow them to feed their prodigious biomass comfortably and with little fear of starvation.

The impact of humans

All this must have changed in the 20th Century, as humans blundered into their ecologies, killing huge numbers of whales and elephants, and laying waste to their food resources.  At the same time that new political agreements, new negotiations and cultures were necessary for their survival, we have killed the oldest, largest, and wisest matriarchs who might have guided this process. 

In my fantasy, the worldwide Orca community ate only fish until they faced a crisis in the mid-20th Century precipitated by human overfishing.  They shared information and held meetings about the extent of the damage.  They were shocked and saddened by the oblivious, blundering behavior of humans, but they were too wise to try to go to war, to take retribution against humans.  Perhaps they knew that this would trigger an extermination campaign that went beyond harpoons to machine guns.  There was a deep divide in opinion; some orcas thought they had no choice but to expand their hunting to walruses, seals, and porpoises in order to continue to live with the freedom they had once known; others must have thought that hunting mammals was barbaric, akin to cannibalism.  Perhaps the two orca cultures agreed to disagree, and have lived in separate communities for decades, though their territories are not at all separate.

Can humans learn from animals?

Man is in uncharted territory because in the last 150 years we have learned to increase our life span to the point where our population growth far outstrips the growth of our historic food species.  We have made up the difference by harnessing fossil energy sources to expand our habitat, and by farming on a global scale, transforming natural ecosystems into artificial ecosystems.  We don’t know how long this process can continue, and we don’t know whether our engineering can secure the fragility of artificial ecosystems.  We have not yet begun to face the Law of Unintended Consequences.   Hence “uncharted territory”.

But perhaps we have something to learn from the orcas and the elephants.

How many headlines have you seen that purport to reveal THE secret of aging?  Just in the last few weeks,  there have been several fundamental, earthshaking, paradigm-shifting, game-changing, disruptive discoveries–and they were very different one from another.

Why do these headlines keep popping up?  Is there truth in any of them?  …and, most interesting to me, What is it that they are all missing?

I’m a culprit in this game, too.  My publisher wants to call my forthcoming book Cracking the Aging Code.

I’m going to cover seven of these news releases below; I trust you’ll let me know if you want to hear more about any of them in particular.

What to Eat while FastingI have posted a page of recipes for my variation on Longo’s Fasting-Mimicking Diet.  These recipes are not endorsed by Dr Longo, but they have the same profile of macronutrients (calories, protein, fats, carbohydrates) as the products soon to be available from L-Nutra. These recipes are based on fresh foods, and the fiber content is much higher than the FMD that Dr Longo has tested.  Intuition tells me that fiber can only add benefit, but this is untested.

Delay of Aging by Remote Control

“UCLA biologists have identified a gene that can slow the aging process throughout the entire body when activated remotely in key organ systems.”  [Science Daily from last fall]

AMP Kinase is a key chemical workhouse for energy production and regulation.  In this study, the AMPK gene in fruit flies was found to be a signal that controls autophagy throughout the body.  (Background: Autophagy is recycling at the cellular level.  It declines through the life span, with the result that molecular gunk accumulates and production of properly-formed proteins declines.)

Life span and health span of the flies were increased when the gene for AMPK was activated in the nervous system, and independently in the digestive system.

 

Role of Mitochondrial Damage vs Epigenetics

Jun-ichi Hayashi of Tsukuba University was an early enthusiast of the mitochondrial free radical theory of aging, who became convinced by his own lab results that the theory doesn’t work.

Background: Mitochondria are thousands of organelles inside a cell that burn sugar for electrochemical energy that the cell can use.  They have their own DNA and their own reproductive cycles within a cell.  They generate reactive oxygen species (ROS) as a byproduct, and it was an attractive theory to attribute aging to damage and mutations they suffer because they are at ground zero for high concentrations of ROS.

Over the last two decades, we have learned that mitochondria do indeed play a central role in aging, but the story is not about simple damage.  In his latest paper [research article, Science Daily report], researchers from Hayashi’s lab show that there is no difference in the amount of DNA damage in mitochondria from cells of young people and from old people.  Why then do mitochondria perform less well, and provide less energy in older people?  They go on to propose that it is the epigenetic programming (in the cell nucleus, not the mitochondria) that makes the difference, and they identified two genes (GCAT and SHMT2)  that may be all that is needed to restore youthful function to the mitochondria.  These genes control production of glycine, the simplest of the 20 amino acids that are common protein constitutents.  Simply feeding the cells with glycine also improved mitochondrial function.  (You can buy glycine tablets as a supplement, but the body already has a lot, so it’s a good guess you would need a lot of it to make a difference.  Food sources rich in glycine include gelatin, shrimp, spirulina, and raw ostrich meat.)

 

Simple Flip of a Genetic Switch

Johnathan Labbadia at Northwestern University has discovered an epigenetic switch, a set of genes that is turned on that begins the aging process in lab worms [Research article from the Morimoto lab, Science Daily summary].  Worms begin aging at the tender age of 3 days, just a few hours after adulthood, with a switch that represses Heat Shock Protein.  HSP is not jus for heat, but a high-level signal that invokes a set of responses that create resiliency in response to stress of many kinds.  In worms and in other animals, stress resistance is closely associated with longevity, and HSP is associated with longer life span in worms [ref].

Scientists who see aging as a purposeful, programmed event, myself included, look to mechanisms of epigenetic control, as we are hopeful that signaling can be modified to avert aging.  But traditional evolutionary biology denies that there can be such direct control of aging.  According to theory, such switches could only be flipped if flipping them increased reproduction in a way that more than offsets the loss of reproductive opportunity from aging.  In keeping with the standard theories, Labbadia and Morimoto, looked for a connection to reproduction in the epigenetic switch they discovered.  They found one, but–undermining the theory–they found that the benefits for reproduction and the costs in the form of aging could be easily separated.

“In one experiment, the researchers blocked the germline from sending the signal to turn off cellular quality control. They found the somatic tissues remained robust and stress resistant in the adult animals.”

Why doesn’t the worm do this, and get the best of both?  Must be some kind of mistake, the Northwestern team asserts.  “Dysregulation” has become a favorite word, though many have enough integrity and insight to be scratching their heads, wondering why there should be so much “dysregulation” involved in aging, when we rarely find anything else about the metabolism that is consistently dysregulated.

 

Older Blood Vessels are Better Protected against Oxidative Stress

This press release from University of Missouri descirbes evidence that cells of the arterial lining (epithelium) are more resistant to oxidative damage when they are older.  Research from the lab of Steven Segal used hydrogen peroxide (H2O2) as a stressor.  Peroxide is also known to be a multi-purpose signal molecule that can induce cell suicide (apotosis) in high concentrations, and can induce protective anti-aging response at lower levels [ref, ref].

The article is framed within an old and discredited view of that regards aging as a simple result of oxidative damage [ref].

“Although the causes of many age-related diseases remain unknown, oxidative stress is thought to be the main culprit. Oxidative stress has been linked to cardiovascular and neurodegenerative diseases including diabetes, hypertension and age-related cancers.”

It should no longer surprise us that anti-oxidants are not anti-aging [ref], or that pro-oxidants can be anti-aging [ref], or that aging is an active process controlled by central signals, not a passive process of damage [ref].

 

Getting to the Bottom of Aging

This article claims to find the root of aging at the cellular level.  In particular, it is in the endoplastic reticulum [background in a Kahn video]. The ER is a transport network inside the cell that directs each protein molecule to a targeted location.  It does more than this–it finishes and folds the protein after it is manufactured.  The new study finds differences between the ER of old and young cells, studied in lab worms and in cultured human cells.  [Here is a Science Daily summary.]  Proteins tend to be misformed and misfolded by the ER of old cells..

In direct contrast to the article just above on blood vessels (“oxidative stress is thought to be the main culprit” ), the claim here is that there is not enough oxidation in the ER of old cells.  It is the reduced state of the ER that is responsible for misfolding of proteins.

 

Diverging Paths from Parabiosis Experiments:  GDF11 and TGF-β

In the early 2000s, Irina Conboy and Amy Wagers were grad students in Tom Rando’s Stanford University lab, studying parabiosis in mice.  They learned that tissues in an old mouse could be rejuvenated by exchanging blood plasma with a young mouse.

Blood plasma is the liquid, containing dissolved signal molecules but no whole blood cells, no stem cells.  The implication was that the old tissues could receive instructions from other parts of the body (an epigenetic clock?) causing them to get older or to revert to a younger state.

Following up on this work: Now Irina and her husband Mike Conboy have a lab at UC Berkeley, where they are focusing on TGF-β as one of the signals that causes aging.  They are experimenting with a drug that blocks TGF-β receptor, and found that it has rejuvenating effects both on muscle and brain cells [press release, research article].  The implication is that excessive TGF-β in the blood is a source of aging.

Wagers is at the Harvard Stem Cell Center, where her biggest trophy so far is the discovery that GDF11 has rejuvenating effects in muscle and nerve cells.  The implication is that there is not enough GDF11 in the blood in the blood of older mammals, and this is a source of aging.

The irony is that GDF11 is a form of TGF-β.  The findings of Wagers and Conboy have diverged to the point where they have focused on the same signal as pro-aging (Conboy) and anti-aging (Wagers).

I don’t have the expertise to take sides in this disagreement, but others have noted that Wagers’s claim seems counter-intuitive. Doubts were expressed about Wagers’s findings by researchers at Novartis (a Cambridge, MA pharmaceutical lab), where David Glass claims he has been unable to duplicate Wagers’s work, and that in his experiments with mice, GDF11 seems to decline with age.

Wikipedia says, “GDF11 is a myostatin-homologous protein that acts as an inhibitor of nerve tissue growth. GDF11 has been shown to suppress neurogenesis through a pathway similar to that of myostatin.” [emphasis added].  Myostatin is an inhibitor of muscle growth whose structure is 90% homologous to GDF11.

“The challenge ahead is to carefully retune the various signaling pathways in the stem cell environment, using a small number of chemicals, so that we end up recalibrating the environment to be youth-like,” Conboy said. “Dosage is going to be the key to rejuvenating the stem cell environment.”

 

Keeping your Brain Active with Balance Exercises A pilot study by Ross and Tracy Alloway of Univ North Florida suggests that balance exercises improve working memory and protect against neurodegenerative disease. [UNF press release]  The focus of the study is termed “proprioception”, awareness of body position. We all lose brain cells with age, and I think of Alzheimer’s dementia as one end of a spectrum.  Some herbs have been studied for neuroprotective effects.  Vigorous exercise is neuroprotective. In parallel to my life as a scientist, I have always practiced yoga and I have taught one yoga class each week for almost 40 years.  Balance exercises are an essential aspect of yoga.  Intuition tells me there is an anti-aging benefit in yoga practice, and there is implicit evidence for this.  I think the connection between yoga and aging deserves a lot more study, but of course it cannot be done with animals, and blinded, controlled experiments are not feasible.