More and more scientists are exploring cellular senescence – a state in which cells no longer divide.
Senescent cells, which accumulate in older bodies, have been linked to age-related conditions such as dementia and cardiovascular disease.
Scientists are exploring drugs that target senescent cells. But the most promising tool against the negative effects of senescent cells, experts say, is exercise.
“A very hot topic”
Viviana Perez Montes of the National Institutes of Health described cellular senescence as “a topic.” The Associated Press reports that about 11,500 projects involving cellular senescence have begun since 1985. The AP’s report was based on its study of an NIH research database. A large number of projects have started in recent years, according to the report.
This research is based on the idea that cells stop dividing and enter a state of “senescence” in response to damage. The body expels most of these cells.
But others remain in the body. They can damage nearby cells, says Nathan LeBrasseur of the Mayo Clinic. He compared it to how one bad fruit can ruin a container full of fruit.
But scientists are wondering: can we stop the unhealthy buildup of senescent cells?
“The ability to understand aging…is truly the greatest opportunity we had, perhaps in history, to transform human health,” says LeBrasseur. Extending healthy years affects “quality of life” and “public health”, he said.
The number of people aged 65 or over is expected to double worldwide by 2050.
Although no one believes senescence holds the key to an extremely long life, Tufts University researcher Christopher Wiley hopes for a day when fewer people suffer like his grandfather did before he died. He had Alzheimer’s disease.
“I’m not looking for the fountain of Youth“, says Wiley. “I’m looking for the fountain to not be sick when I get older.
About 100 companies, as well as academic groups, are exploring drugs to target senescent cells.
Scientists are careful to note that cellular senescence can be helpful. The process probably developed at least in part to suppress the development of cancer. Cellular senescence occurs throughout our lives, caused by things like DNA damage and the shortening of telomeres, structures that protect the ends of chromosomes. Senescent cells play a role in wound healing, embryonic development and childbirth.
But problems can arise when senescent cells accumulate.
“When you’re young, your immune system is able to recognize these senescent cells and eliminate them,” says Perez, who studies cell biology and aging. But, as we begin to age, in Perez’s words, “our immune system activity also becomes decreasesso we lose the ability to eliminate them. »
Experimental drugs designed to eliminate senescent cells have been called “senolytics”. In mice, they have been shown to be effective in delaying, preventing or alleviating several age-related disorders.
At least 12 clinical trials with senolytics are now testing whether the drugs can help control Alzheimer’s disease, improve skeletal health and more.
There is still a lot to learn.
Today, LeBrasseur, who runs a center on aging in Mayo, says exercise is “the most promising tool we have” for good health in later life, and its power extends to our cells.
Research suggests that exercise thwarts the buildup of senescent cells, helping the immune system clear them and fight molecular damage that can affect the senescence process.
Last year, LeBrasseur conducted a study that provided the first evidence in humans that exercise significantly affected the process. It reduced the signs in the bloodstream of the effects of senescent cells in the body.
After a 12-week exercise program, researchers found that older adults showed decreased signs of senescence and improved muscle strength, physical ability, and self-reported health. A recently published research review is gathering even more evidence — in animals and humans — for exercise as a therapy targeting senescence.
Although such studies are not well known outside of scientific circles, many older people associate exercise with youth.
Breeder Mike Gale, 81, has set up an athletic throwing circle on his large property in California. He and some of his friends throw the disc and use other exercise equipment.
“I would love to compete in my 90s,” Gale says. “Why not?”
Richard Soller, 95, says exercise keeps him fit enough to deal with what comes his way, including the discovery that his 62-year-old wife had developed Alzheimer’s disease. The two sometimes walk the streets of their neighborhood together, hand in hand.
“Do as much as you can,” he says. “That should be the goal for anyone to stay healthy.”
I am John Russell.
And I’m Ashley Thompson.
Laura Ungar reported this story for The Associated Press. John Russell adapted it for VOA Learning English.
words in this story
topic – nm someone or something people talk about or write about
opportunity – nm a time frame or situation in which something can be done
transform – v. to change (something) completely and generally in a good way
fountain of Youth – expression a legendary fountain that is believed to give eternal youth to anyone who drinks from it
heel – v. to become or cause (something) to become less big, important, etc.
ability – nm the ability to do something: a mental, emotional or physical ability
clinical – adj. relating to or based on work done with real patients: of or relating to the medical treatment that is given to patients in hospitals, clinics, etc.