Lifespan. Dr David A. Sinclair

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Lifespan - Dr David A. Sinclair

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One of our key findings, in a study we published in 2018,42 was that when treated with an NAD-boosting molecule that activated the SIRT1 enzyme, the elderly mice’s endothelial cells, which line the blood vessels, were pushing their way into areas of the muscle that weren’t getting very much blood flow. New tiny blood vessels, capillaries, were formed, supplying badly needed oxygen, removing lactic acid and toxic metabolites from muscles, and reversing one of the most significant causes of frailty in mice and in humans. That was how these old mice suddenly became such mighty marathoners.

      Because the sirtuins had been activated, the mice’s epigenomes were becoming more stable. The valley walls were growing higher. Gravity was growing stronger. And Waddington’s marbles were being pushed back to where they belonged. The lining of the capillaries was responding as if the mice were exercised. It was an exercise mimetic, the first of its kind, and a sure sign that some aspects of age reversal are possible.

      We still don’t know everything about why this happens. We don’t know what sorts of molecules will work best for activating sirtuins or in what doses. Hundreds of different NAD precursors have been synthesized, and there are clinical trials in progress to answer that question and more.

      But that doesn’t mean we need to wait to take advantage of all that we’ve learned about engaging the epigenetic survival circuit and living longer and healthier lives. We don’t need to wait to take advantage of the Information Theory of Aging.

      There are steps we can take right now to live much longer and much healthier lives. There are things we can do to slow, stop, and even reverse aspects of aging.

      But before we talk about what steps we might take to combat aging, before I can explain the science-backed interventions that have the greatest promise for fundamentally changing the way we think about growing old, before we even begin to talk about the treatments and therapies that will be game changers for our species, we need to answer one very important question:

      Should we?

       THREE

       THE BLIND EPIDEMIC

      IT WAS MAY 10, 2010, AND LONDON WAS ABUZZ. CHELSEA FOOTBALL CLUB HAD just won its fourth national championship by devastating Wigan Athletic, 8–0, on the final day of Premier League play. Meanwhile, Gordon Brown announced that he would be stepping down as prime minister in response to a disastrous parliamentary result for his Labour Party, which had lost more than ninety seats in the previous week’s general election.

      With the eyes of the English sports world on one part of London and the attention of the British political universe on another, the goings-on at Carlton House Terrace were missed by all but the most attentive observers of the president, council, and fellows of the Royal Society of London for Improving Natural Knowledge.

      More simply known as the Royal Society, the world’s oldest national scientific organization was established in 1660 to promote and disseminate “new science” by big thinkers of the day such as Sir Francis Bacon, the Enlightenment’s promulgator of “the prolongation of life.”1 Befitting its rich scientific history, the society has held annual scientific events ever since. Highlights have included lectures by Sir Isaac Newton on gravity, Charles Babbage on his mechanical computer, and Sir Joseph Banks, who had just arrived back from Australia with a bounty of more than a thousand preserved plants that were all new to science.

      Even today, in a post-Enlightenment world, most of the events at the society are fascinating if not world changing. But the two-day meeting that commenced in the spring of 2010 was nothing short of that, for gathered together on that Monday and Tuesday was a motley group of researchers who were meeting to discuss an important “new science.”

      The gathering had been called by geneticist Dame Linda Partridge, bioanalytics pioneer Janet Thornton, and molecular neuroscientist Gillian Bates, all luminaries in their respective fields. The attendee list was no less impressive. Cynthia Kenyon spoke about her landmark work on a single mutation in the IGF-1 receptor gene that had doubled the lifespan of roundworms by activating DAF-162—work that was first suggested by Partridge to be a worm-specific aberration3 but soon forced her and other leading researchers to confront long-held beliefs that aging could be controlled by a single gene. Thomas Nyström, from the University of Gothenburg, reported his discovery that Sir2 not only is important for genomic and epigenomic stability in yeast, it also prevents oxidized proteins from being passed on to young daughter cells.

      Brian Kennedy, a former Guarente student who was about to assume the presidency of the Buck Institute for Research on Aging, explained the ways in which genetic pathways that had been similarly conserved in a diverse array of species were likely to play similar roles in mammalian aging. Andrzej Bartke from Southern Illinois University, former PhD adviser to Michael “Marathon Mouse” Bonkowski, talked about how dwarf mice can live up to twice as long as normal mice, a record. Molecular biologist María Blasco explained how old mammalian cells are more likely than young cells to lose their identity and become cancerous. And geneticist Nir Barzilai spoke of genetic variants in long-lived humans and his belief that all aging-related diseases can be substantially prevented and human lives can be considerably extended with one relatively easy pharmaceutical intervention.

      Over the course of those two days, nineteen presenting scientists from some of the best research institutions in the world moved toward a provocative consensus and began to build a compelling case that would challenge conventional wisdom about human health and disease. Summarizing the meeting for the society later that fall, the biogerontologist David Gems would write that advances in our understanding of organismal senescence are all leading to a momentous singular conclusion: that aging is not an inevitable part of life but rather a “disease process with a broad spectrum of pathological consequences.”4 In this way of thinking, cancer, heart disease, Alzheimer’s, and other conditions we commonly associate with getting old are not necessarily diseases themselves but symptoms of something greater.

      Or, put more simply and perhaps even more seditiously: aging itself is a disease.

      THE LAW OF HUMAN MORTALITY

      If the idea that aging is a disease sounds strange to you, you’re not alone. Physicians and researchers have been avoiding saying that for a long time. Aging, we’ve long been told, is simply the process of growing old. And growing old has long been seen as an inevitable part of life.

      We see aging, after all, in nearly everything around us and, in particular, the things around us that look anything like us. The cows and pigs in our farms age. The dogs and cats in our homes do, too. The birds in the sky. The fish in the sea. The trees in the forest. The cells in our petri dishes. It always ends the same way: dust to dust.

      The connection between death and aging is so strong that the inevitability of the former governed the way we came to define the latter. When European societies first began keeping public death certificates in the 1600s, aging was a respected cause of death. Descriptions such as “decrepitude” or “feebleness due to old age” were commonly accepted explanations for death. But according to the seventeenth-century English demographer John Graunt, who wrote Natural and Political Observations Mentioned in a Following Index, and Made upon the Bills of Mortality, so were “fright,” “grief,” and “vomiting.”

      As we’ve moved forward in time, we’ve moved away from blaming death on old age. No one dies anymore from “getting old.” Over the past century, the Western medical community has come to believe not only that there is always a more immediate cause of death than aging

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