Could Getting Rid of Old Cells Turn Back the Clock on Aging?

Long-time geriatrician James Kirkland is a Mayo clinic researcher joining "a growing movement to halt chronic disease by protecting brains and bodies from the biological fallout of aging," reports Ars Technica. "While researchers like Kirkland don't expect to extend lifespan, they hope to lengthen 'health span,' the time that a person lives free of disease."One of their targets is decrepit cells that build up in tissues as people age. These "senescent" cells have reached a point - due to damage, stress or just time - when they stop dividing, but don't die. While senescent cells typically make up only a small fraction of the overall cell population, they accounted for up to 36 percent of cells in some organs in aging mice, one study showed. And they don't just sit there quietly. Senescent cells can release a slew of compounds that create a toxic, inflamed environment that primes tissues for chronic illness. Senescent cells have been linked to diabetes, stroke, osteoporosis and several other conditions of aging. These noxious cells, along with the idea that getting rid of them could mitigate chronic illnesses and the discomforts of aging, are getting serious attention. The U.S. National Institutes of Health is investing $125 million in a new research effort, called SenNet, that aims to identify and map senescent cells in the human body as well as in mice over the natural lifespan. And the National Institute on Aging has put up more than $3 million over four years for the Translational Geroscience Network multicenter team led by Kirkland that is running preliminary clinical trials of potential antiaging treatments. Drugs that kill senescent cells - called senolytics - are among the top candidates. Small-scale trials of these are already underway in people with conditions including Alzheimer's, osteoarthritis and kidney disease. "It's an emerging and incredibly exciting, and maybe even game-changing, area," says John Varga, chief of rheumatology at the University of Michigan Medical School in Ann Arbor, who isn't part of the Translational Geroscience Network. But he and others sound a note of caution as well, and some scientists think the field's potential has been overblown. "There's a lot of hype," says Varga. "I do have, I would say, a very healthy skepticism." He warns his patients of the many unknowns and tells them that trying senolytic supplementation on their own could be dangerous.... So far, evidence that destroying senescent cells helps to improve health span mostly comes from laboratory mice. Only a couple of preliminary human trials have been completed, with hints of promise but far from blockbuster results. In conjunction with SpaceX and Axiom Space, Kirkland and a colleague also are investigating how space radiation affects senescence indicators in astronauts, the article points out . "They hypothesize that participants in future long-term missions to Mars might have to monitor their bodies for senescence or pack senolytics to stave off accelerated cellular aging caused by extended exposure to radiation."

Read more of this story at Slashdot.