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Jeff Bezos is on a mission to conquer the aging process. He has just recruited Hal Barron from GlaxoSmithKline to lead Altos Labs (alongside a number of Nobel Prize-winning scientists), a new startup in the field of biotechnology invested with billions (rumored to be 3 billion dollars) with the ambition to combat aging. How does science explain this? Can we defeat aging?Aging is not just about changes in how we perceive or look, aging occurs at the cellular level. In a petri dish in the laboratory, mature skin cells divide about 50 times before stopping. But skin cells from a newborn can divide 80 or 90 times. On the other hand, cells from an elderly person only divide about twenty times.The aging process is clearly evident in our genes. Our genetic material changes over time, known as epigenetic changes, which occur as we age. Another type of change occurs at the end of our DNA strands, called telomeres, which act like the plastic tips of shoelaces, preventing the genetic material from fraying at the ends or sticking together. However, these telomeres shorten each time a cell divides. We do not know whether short telomeres are just a sign of the aging process, like graying hair, or part of the cell aging process.To sustain life and continue dividing, immune cells stop shortening their telomeres when multiplying, similar to what cancer cells do. This may contribute to their seemingly eternal youthfulness. Drugs that inhibit telomerase activity also hold promise in combating cancer (although cancer cells can develop drug resistance). With aging deeply affecting our cells and genes, a much larger question arises: why does this happen? Why do we age?
It was once believed that aging occurred due to the continuous evolution of species. In other words, the evolution of a species requires the turnover of individuals. However, a problem with this explanation is that most life on Earth never reaches old age. Most animal species are killed by predators, disease, climate, or famine. Thus, the limitation on the lifespan of animals may not be important for the evolutionary process.Another perspective suggests that aging is simply the result of accumulated damage over time caused by metabolic processes or exposure to UV rays from the sun. While we know that genes become damaged as we age, it hasn't been proven to directly drive the aging process. Another possibility is that aging could be seen as a protective measure against cancer. As cells accumulate genetic damage over time, they may have developed a mechanism to not persist in the body for too long, in case this damage eventually leads to cancer.As we age, some cells in the body enter a state called senescence, where a cell remains alive but stops dividing. Senescent cells accumulate in the body throughout our lives - especially in the skin, liver, lungs, and kidneys - which can be both beneficial and harmful. They're beneficial because they release chemical compounds that aid in repairing damaged tissues, but over time, as senescent cells increase in number, they can disrupt the normal structure of organs and tissues. These cells may be the underlying cause of many age-related issues. Removing senescent cells takes longer for mice to show signs of aging. We can describe many aspects of the aging process regarding what happens at the genetic, cellular, and organ levels. But the fundamental question of why we age remains unanswered. There are likely more than one correct answer.
Of course, no one knows whether Bezos' company will succeed in extending human lifespan. But it's clear that through aging research, exciting new discoveries are certain to emerge. Never believe anyone who claims that the big questions have already been answered. Major breakthroughs will profoundly change the human experience in the centuries to come.Theo from BigThink discusses the science of aging.
