Published November 03, 2011
Scientists may have found a way to put off some conditions of aging, according to a study in which they postponed or even prevented such afflictions as cataracts and wrinkle-inducing fat loss in mice by removing cells that had stopped dividing.
Most young, healthy cells divide continuously in order to keep body tissues and organs functioning properly, but eventually stop splitting—a state called senescence—and are replaced by others. Senescence occurs throughout life, but people's ability to clear such cells from their bodies decreases with age, leading to a buildup.
Researchers at the Mayo Clinic in Rochester, Minn., found for the first time that by using a drug to target and kill senescent cells, they could essentially freeze some aspects of the aging process.
Though the research, published Wednesday in the journal Nature, is in its very early stages, it suggests that senescent-cell clearance could be one path to staying healthy while aging.
"If you could clear senescent cells, you perhaps could treat age-related diseases as a group rather than individually," said Jan van Deursen, senior author of the paper and a professor in the departments of biochemistry and pediatric and adolescent medicine at Mayo.
The importance of cell senescence to the aging process has long been suspected. But the latest finding demonstrates definitively that these cells play a role in age-related conditions, according to Felipe Sierra, director of the division of aging biology at the National Institute on Aging, who wasn't involved in the study.
When cells become senescent, they produce harmful compounds such as those that cause inflammation. Chronic tissue inflammation with aging is thought to underlie dementia, atherosclerosis and diabetes, among other ills, according to James Kirkland, head of Mayo's Center on Aging, who was also an author of the study.
Senescent cells make up only a small portion of cells—some five percent or less—in the tissue of elderly people, but their effects can be widespread, the researchers said.
Because senescence is believed to have developed as a defense against cancer, in which cells divide uncontrollably, simply halting the process could be dangerous.
But scientists have wondered for decades if the damage inflicted by senescent cells could be stopped if they were removed from the body altogether, or if the harmful substances they produced were neutralized.
The work was funded by the Mayo Clinic, as well as several private foundations and philanthropists interested in promoting research into aging.