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It’s Time to Postpone Your Appointment with the Grim Reaper – Article by Gerrard Jayaratnam

It’s Time to Postpone Your Appointment with the Grim Reaper – Article by Gerrard Jayaratnam

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The New Renaissance HatGerrard Jayaratnam
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How long would you like to live for? Is there a limit to how long we can live for? These are not questions you hear often, but do not be surprised if they are repeated more frequently in the future. The reason? Life extension. It is the concept of living well beyond the average lifespan. [1]

Humans are already living longer due to vaccines and improvements in sanitation. [2] The World Health Organization reported that the average life expectancy at birth increased from 48 years in 1955 to 65 years in 1995, and is projected to rise to 73 years by 2025. [3] As medical techniques continue to improve, we are more inclined than ever to pursue life extension. [1] Indeed, from the Epic of Gilgamesh to China’s First Emperor, prolonging life has been an ever-present thought in society. [4, 5] Both individuals failed to escape death, but the idea of life extension ironically lives on. Even so, is it truly possible and what should upcoming doctors and scientists consider if they are to join the most ambitious of quests?

The “Horcruxes” of reality 

In the fictional Harry Potter series, “Horcruxes” were objects where people could hide a fragment of their soul in an attempt to take one step towards immortality. [6] Of course, humans cannot split their souls and hide them in objects, but there are several proposed means by which life extension may be achieved. [1] This is a testimony to the progress within the life extension field, but there remains much room for improvement.

Eat less, live more

Caloric restriction (CR) is one proposed method for life extension. [1] In the CALERIE (Comprehensive Assessment of Long term Effects of Reducing Intake of Energy) trial, 218 non-obese humans were randomised to either a control group or an intervention group. The latter aimed for a 25% reduction from baseline energy intake. At the end of the 2-year study period, the intervention group had significantly greater reductions in circulating levels of TNF-α – an inflammatory marker involved in many age-related diseases. [7] Dr Alexander Miras, winner of the 2014 Nutrition Society Cuthbertson Medal for his research on bariatric surgery, acknowledges that the study was a “good first step,” but argues that “the evidence in humans is lacking.” “A definitive RCT (randomised controlled trial),” Dr Miras continues, “would be very hard, if not impossible.” He also spots a glaring consequence of CR. “My personal approach is to avoid caloric restriction as this leads to hunger which is an unpleasant feeling. I would rather live a shorter life, but enjoy my food.”

Manipulating telomerase

One alternative is modulating telomerase activity – as attempted with the anti-ageing TA-65MD® supplement. [8] Telomeres protect the ends of chromosomes [9]; they resemble the aglets on the ends of shoelaces. Just as shoelaces would unravel without the aglet, chromosomes would lose vital DNA sequences in the absence of telomeres. [9] Our cells divide over time, causing telomeres to shorten. Once the telomere becomes too short, cell division ceases, and short telomeres correlate with cellular ageing. [10] Telomerase is an enzyme that can oppose telomere shortening [10] – it was what Hamlet was to King Claudius; what exercise is to obesity; and what junior doctors, in England, will be to Jeremy Hunt.

Reactivating telomerase in telomerase-deficient mice reversed both neurodegeneration and degeneration of other organs. [11] This proved the concept that boosting telomerase activity could have anti-ageing effects, but there is little proof that this occurs in humans. While the mice were telomerase-deficient, humans normally have some telomerase activity. It is like giving food to someone who has been fasting for hours and to someone who has just eaten a three-course meal – the starved individual would unquestionably benefit more. A 12-month long RCT, involving 117 relatively healthy individuals (age range: 53-87), found that low-dose TA-65 significantly increased telomere length when compared to placebo. High-dose TA-65, however, failed to do so. [12]

Dancing with the devil

What is more worrying than treatments that may be ineffective? Side effects. Telomerase is a double-edged sword and by reducing telomere attrition, it can promote unlimited cell division and cancer. [9] Elizabeth Blackburn, co-winner of the 2009 Nobel Prize in Physiology or Medicine for her role in the discovery of telomerase, has doubts about exploiting the enzyme. Speaking to TIME magazine, she said, “Cancers love telomerase, and a number of cancers up-regulate it like crazy. . . . My feeling would be that if I take anything that would push my telomerase up, I’m playing with fire.” [13]

A cauldron of rewards

CR and boosting telomerase activity are just a small sample of life extending techniques, yet there is the notion that such techniques will be intertwined with risks. However, risks are always weighed against rewards, and Gennady Stolyarov, editor-in-chief of The Rational Argumentator and Chief Executive of the Nevada Transhumanist Party, believes life extension would bring “immense and multifaceted” rewards. “The greatest benefit is the continued existence of the individual who remains alive. Each individual has incalculable moral value and is a universe of ideas, experiences, emotions, and memories. When a person dies, that entire universe is extinguished . . . This is the greatest possible loss, and should be averted if at all possible.” Stolyarov also envisages “major savings to healthcare systems” and that “the achievement of significant life extension would inspire many intelligent people to try to solve other age-old problems.”

Former chairman of the President’s Council on Bioethics, Leon Kass, disagrees with this view and argues that mortality is necessary for “treasuring and appreciating all that life brings.” [14] Hence, increased longevity could lead to an overall reduction in productivity over one’s lifetime. Perhaps Kass is correct, but the array of potential benefits makes it seem unwise to prematurely dismiss life extension. In fact, a survey, which examined the opinions of 605 Australians on life extension, highlighted further benefits – 23% of participants said they could “spend more time with family” and 4% cited the opportunity to experience future societies. [15]

Learning from our mistakes

Conversely, life extension may result in people enduring poor health for longer periods. 28% of participants in the Australian survey highlighted this concern. [15] Current trends in life expectancy reinforce their fears. Professor Janet Lord, director of the Institute of Inflammation and Ageing at the University of Birmingham, explains, “Currently, in most countries in the developed world, life expectancy is increasing at approximately 2 years per decade, but healthspan (the years spent in good health) is only increasing at 1.7 years. This has major consequences . . . as more of later life is spent in poor health.” This is a consequence of treating “killer diseases” – according to Dr Felipe Sierra, director of the Division of Aging Biology at the National Institute on Aging. “The current model in biomedicine,” says Dr Sierra, “is to treat one disease at a time. Let’s imagine you have arthritis; cancer; and are starting to develop Alzheimer’s disease. So what do we do? We treat you for cancer. You now live longer with Alzheimer’s disease and arthritis.” A better approach is clear to Dr Sierra who stresses the importance of compression of morbidity – “the goal is to live longer with less time spent being sick.”

Learning from our successes

Even with Dr Sierra’s approach, individual boredom and social implications, including overpopulation, would still be problems.[16] According to Stolyarov, the boredom argument does not hold up when facing “human creativity and discovery.” He believes humans could never truly be bored as “the number of possible pursuits increases far faster than the ability of any individual to pursue.”

In his novel Death is Wrong, Stolyarov explained that the idea that society could not cope with a rapidly expanding population was historically inaccurate. The current population “is the highest it has ever been, and most people live far longer, healthier, prosperous lives than their ancestors did when the Earth’s population was hundreds of times smaller.” [16] If it has been achieved in the past, who is to say our own society – one far more advanced than any before it – cannot adapt?

The verdict

Life extension research is quietly progressing, and there is a good chance that it will eventually come to fruition. Although there are doubts about current techniques, Dr Sierra draws attention to novel interventions, such as rapamycin, which “delay ageing in mice.” He concludes that the next challenge is to “develop measures than can predict whether an intervention works in a short-term assay.” Such measures would provide the scaffolding for future clinical trials that test life extension techniques.

Given what may be gained, it is no surprise that artificially prolonging life is exciting some in the same way the Tree of Knowledge tempted Eve. The impact on society? Impossible to predict. It would undoubtedly be a big risk, but perhaps in this complex and uncertain scenario, we ought to remember the words of the poet Thomas Stearns Eliot: “Only those who will risk going too far can possibly find out how far one can go.” [17]

Gerrard Jayaratnam is a student of Biomedical Science at Imperial College London.

References

  1. Stambler I. A History of Life-Extensionism in the Twentieth Century. Ramat Gan: CreateSpace Independent Publishing Platform; 2014.
  2. National Institute on Aging. Living Longer. 2011. https://www.nia.nih.gov/research/publication/global-health-and-aging/living-longer.
  3. World Health Organization. 50 Facts: Global Health situation and trends 1955-2025. 2013. http://www.who.int/whr/1998/media_centre/50facts/en/.
  4. Encyclopaedia Britannica. Epic of Gilgamesh. 2016. http://www.britannica.com/topic/Epic-of-Gilgamesh.
  5. Lloyd DF. The Man Who Would Cheat Death and Rule the Universe. Vision. 2008. http://www.vision.org/visionmedia/history-shi-huang-emperor-china/5818.aspx.
  6. Rowling JK. Harry Potter and the Half-Blood Prince. London: Bloomsbury Publishing; 2005.
  7. Ravussin E, Redman LM, Rochon J, et al. A 2-Year Randomized Controlled Trial of Human Caloric Restriction: Feasibility and Effects on Predictors of Health Span and Longevity. J Gerontol A Biol Sci Med Sci 2015;70:1097-1104.
  8. A. Sciences. What is TA-65®? (n.d.) [Accessed 3rd April 2016]. https://www.tasciences.com/what-is-ta-65/.
  9. De Jesus BB, Blasco MA. Telomerase at the intersection of cancer and aging. Trends Genet 2013;29:513-520.
  10. A. Sciences. Telomeres and Cellular Aging. (n.d.) [Accessed 3rd April 2016]. https://www.tasciences.com/telomeres-and-cellular-aging/.
  11. Jaskelioff M, Muller FL, Paik JH, et al. Telomerase reactivation reverses tissue degeneration in aged telomerase deficient mice. Nature 2011;469:102-106.
  12. Salvador L, Singaravelu G, Harley CB, et al. A Natural Product Telomerase Activator Lengthens Telomeres in Humans: A Randomized, Double Blind, and Placebo Controlled Study. Rejuvenation Res 2016; ahead of print. doi:10.1089/rej.2015.1793.
  13. Kluger J. The antiaging power of a positive attitude. TIME. 2015.
  14. Than K. The Psychological Strain of Living Forever. Live Science. 2006. http://www.livescience.com/10469-psychological-strain-living.html.
  15. Partridge B, Lucke J, Bartlett H, et al. Ethical, social, and personal implications of extended human lifespan identified by members of the public. Rejuvenation Res 2009;12:351-357.
  16. Stolyarov II G. Death is Wrong. 2nd ed. Carson City, Nevada: Rational Argumentator Press; 2013.
  17. The Huffington Post. 11 Beautiful T.S. Eliot Quotes. 2013. http://www.huffingtonpost.com/2013/09/26/ts-eliot-quotes_n_3996010.html.
The Two Faces of Aging: Cancer and Cellular Senescence – Article by Adam Alonzi

The Two Faces of Aging: Cancer and Cellular Senescence – Article by Adam Alonzi

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The New Renaissance Hat
Adam Alonzi
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This article is republished with the author’s permission. It was originally posted on Radical Science News.

hELA-400x300Multiphoton fluorescence image of HeLa cells.

Aging, inflammation, cancer, and cellular senescence are all intimately interconnected. Deciphering the nature of each thread is a tremendous task, but must be done if preventative and geriatric medicine ever hope to advance. A one-dimensional analysis simply will not suffice. Without a strong understanding of the genetic, epigenetic, intercellular, and intracellular factors at work, only an incomplete picture can be formed. However, even with an incomplete picture, useful therapeutics can be and are being developed. One face is cancer, in reality a number of diseases characterized by uncontrolled cell division. The other is degradation, which causes a slue of degenerative disorders stemming from deterioration in regenerative capacity.

Now there is a new focus on making geroprotectors, which are a diverse and growing family of compounds that assist in preventing and reversing the unwanted side effects of aging. Senolytics, a subset of this broad group, accomplish this feat by encouraging the removal of decrepit cells. A few examples include dasatinib, quercetin, and ABT263. Although more research must be done, there are a precious handful of studies accessible to anyone with the inclination to scroll to the works cited section of this article. Those within the life-extension community and a few enlightened souls outside of it already know this, but it bears repeating: in the developed world all major diseases are the direct result of the aging process. Accepting this rather simple premise, and you really ought to, should stoke your enthusiasm for the first generation of anti-aging elixirs and treatments. Before diving into the details of these promising new pharmaceuticals, nanotechnology, and gene therapies we must ask what is cellular senescence? What causes it? What purpose does it serve?

Depending on the context in which it is operating, a single gene can have positive or negative effects on an organism’s phenotype. Often the gene is exerting both desirable and undesirable influences at the same time. This is called antagonistic pleiotropy. For example, high levels of testosterone can confer several reproductive advantages in youth, but in elderly men can increase their likelihood of developing prostate cancer. Cellular senescence is a protective measure; it is a response to damage that could potentially turn a healthy cell into a malignant one. Understandably, this becomes considerably more complex when one is examining multiple genes and multiple pathways. Identifying all of the players involved is difficult enough. Conboy’s famous parabiosis experiment, where a young mouse’s system revived an old ones, shows that alterations in the microenviornment, in this case identified and unidentified factors in the blood of young mice, can be very beneficial to their elders. Conversely, there is a solid body of evidence that shows senescent cells can have a bad influence on their neighbors. How can something similar be achieved in humans without having to surgically attach a senior citizen to a college freshman?

By halting its own division, a senescent cell removes itself as an immediate tumorigenic threat. Yet the accumulation of nondividing cells is implicated in a host of pathologies, including, somewhat paradoxically, cancer, which, as any life actuary’s mortality table will show, is yet another bedfellow of the second half of life. The single greatest risk factor for developing cancer is age. The Hayflick Limit is well known to most people who have ever excitedly watched the drama of a freshly inoculated petri dish. After exhausting their telomeres, cells stop dividing. Hayflick et al. astutely noted that “the [cessation of cell growth] in culture may be related to senescence in vivo.” Although cellular senescnece is considered irreversible, a select few cells can resume normal growth after the inactivation of the p53 tumor suppressor. The removal of p16, a related gene, resulted in the elimination of the progeroid phenotype in mice. There are several important p’s at play here, but two are enough for now.

Our bodies are bombarded by insults to their resilient but woefully vincible microscopic machinery. Oxidative stress, DNA damage, telomeric dysfunction, carcinogens, assorted mutations from assorted causes, necessary or unnecessary immunological responses to internal or external factors, all take their toll. In response cells may repair themselves, they may activate an apoptotic pathway to kill themselves, or just stop proliferating. After suffering these slings and arrows, p53 is activated. Not surprisingly, mice carrying a hyperactive form of p53 display high levels of cellular senescence. To quote Campisi, abnormalities in p53 and p15 are found in “most, if not all, cancers.” Knocking p53 out altogether produced mice unusually free of tumors, but those mice find themselves prematurely past their prime. There is a clear trade-off here.

In a later experiment Garcia-Cao modified p53 to only express itself when activated. The mice exhibited normal longevity as well as an“unusual resistance to cancer.” Though it may seem so, these two cellular states are most certainly not opposing fates. As it is with oxidative stress and nutrient sensing, two other components of senescence or lack thereof, the goal is not to increase or decrease one side disproportionately, but to find the correct balance between many competing entities to maintain healthy homeostasis. As mentioned earlier, telomeres play an important role in geroconversion, the transformation of quiescent cells into senescent ones. Meta-analyses have shown a strong relationship between short telomeres and mortality risk, especially in younger people. Although cancer cells activate telomerase to overcome the Hayflick Limit, it is not entirely certain if the activation of telomerase is oncogenic.

majormouse

SASP (senescence-associated secretory phenotype) is associated with chronic inflammation, which itself is implicated in a growing list of common infirmities. Many SASP factors are known to stimulate phenotypes similar to those displayed by aggressive cancer cells. The simultaneous injection of senescent fibroblasts with premalignant epithelial cells into mice results in malignancy. On the other hand, senescent human melanocytes secrete a protein that induces replicative arrest in a fair percentage of melanoma cells. In all experiments tissue types must be taken into account, of course. Some of the hallmarks of inflammation are elevated levels of IL-6, IL-8, and TNF-α. Inflammatory oxidative damage is carcinogenic and an inflammatory microenvironment is a good breeding ground for malignancies.

Caloric restriction extends lifespan in part by inhibiting TOR/mTOR (target of rapamycin/mechanistic target of rapamycin, also called  the mammalian target of rapamycin). TOR is a sort of metabolic manager, it receives inputs regarding the availability of nutrients and stress levels and then acts accordingly. Metformin is also a TOR inhibitor, which is why it is being investigated as a cancer shield and a longevity aid. Rapamycin has extended average lifespans in all species tested thus far and reduces geroconversion. It also restores the self-renewal and differentiation capacities of haemopoietic stem cells. For these reasons the Major Mouse Testing Program is using rapamycin as its positive control. mTOR and p53 dance (or battle) with each other beautifully in what Hasty calls the “Clash of the Gods.” While p53 inhibits mTOR1 activity, mTOR1 increases p53 activity. Since neither metformin nor rapamycin are without their share of unwanted side effects, more senolytics must be explored in greater detail.

Starting with a simple premise, namely that senescent cells rely on anti-apoptotic and pro-survival defenses more than their actively replicating counterparts, Campisi and her colleagues created a series of experiments to find the “Achilles’ Heel” of senescent cells. After comparing the two different cell states, they designed senolytic siRNAs. 39 transcripts were selected for knockdown by siRNA transfection, and 17 affected the viability of their target more than healthy cells. Dasatinib, a cancer drug, and quercitin, a common flavonoid found in common foods, have senolytic properties. The former has a proven proclivity for fat-cell progenitors, and the latter is more effective against endothelial cells. Delivered together, they they remove senescent mouse embryonic fibroblasts. Administration into elderly mice resulted in favorable changes in SA-BetaGAL (a molecule closely associated with SASP) and reduced p16 RNA. Single doses of D+Q together resulted in significant improvements in progeroid mice.

If you are not titillated yet, please embark on your own journey through the gallery of encroaching options for those who would prefer not to become chronically ill, suffer immensely, and, of course, die miserably in a hospital bed soaked with several types of their own excretions―presumably, hopefully, those who claim to be unafraid of death have never seen this image or naively assume they will never be the star of such a dismal and lamentably “normal” final act. There is nothing vain about wanting to avoid all the complications that come with time. This research is quickly becoming an economic and humanitarian necessity. The trailblazers who move this research forward will not only find wealth at the end of their path, but the undying gratitude of all life on earth.

Adam Alonzi is a writer, biotechnologist, documentary maker, futurist, inventor, programmer, and author of the novels “A Plank in Reason” and “Praying for Death: Mocking the Apocalypse”. He is an analyst for the Millennium Project, the Head Media Director for BioViva Sciences, and Editor-in-Chief of Radical Science News. Listen to his podcasts here. Read his blog here.

References

Blagosklonny, M. V. (2013). Rapamycin extends life-and health span because it slows aging. Aging (Albany NY), 5(8), 592.

Campisi, Judith, and Fabrizio d’Adda di Fagagna. “Cellular senescence: when bad things happen to good cells.” Nature reviews Molecular cell biology 8.9 (2007): 729-740.

Campisi, Judith. “Aging, cellular senescence, and cancer.” Annual review of physiology 75 (2013): 685.

Hasty, Paul, et al. “mTORC1 and p53: clash of the gods?.” Cell Cycle 12.1 (2013): 20-25.

Kirkland, James L. “Translating advances from the basic biology of aging into clinical application.” Experimental gerontology 48.1 (2013): 1-5.

Lamming, Dudley W., et al. “Rapamycin-induced insulin resistance is mediated by mTORC2 loss and uncoupled from longevity.” Science 335.6076 (2012): 1638-1643.

LaPak, Kyle M., and Christin E. Burd. “The molecular balancing act of p16INK4a in cancer and aging.” Molecular Cancer Research 12.2 (2014): 167-183.

Malavolta, Marco, et al. “Pleiotropic effects of tocotrienols and quercetin on cellular senescence: introducing the perspective of senolytic effects of phytochemicals.” Current drug targets (2015).

Rodier, Francis, Judith Campisi, and Dipa Bhaumik. “Two faces of p53: aging and tumor suppression.” Nucleic acids research 35.22 (2007): 7475-7484.

Rodier, Francis, and Judith Campisi. “Four faces of cellular senescence.” The Journal of cell biology 192.4 (2011): 547-556.

Salama, Rafik, et al. “Cellular senescence and its effector programs.” Genes & development 28.2 (2014): 99-114.

Tchkonia, Tamara, et al. “Cellular senescence and the senescent secretory phenotype: therapeutic opportunities.” The Journal of clinical investigation 123.123 (3) (2013): 966-972.

Zhu, Yi, et al. “The Achilles’ heel of senescent cells: from transcriptome to senolytic drugs.” Aging cell (2015).