NEW YORK - Sustaining the hope that human aging might be decelerated, researchers have found they can substantially extend the average life span of obese mice with a specially designed drug.
The drug, SRT-1720, protects the mice from the usual diseases of obesity by reducing the amount of fat in the liver and increasing sensitivity to insulin. These and other positive health effects enable the obese mice to live 44 percent longer, on average, than obese mice that did not receive the drug, say a team of researchers led by Rafael de Cabo, a gerontologist at the National Institute on Aging.
Drugs closely related to SRT-1720 are undergoing clinical trials.
The findings “demonstrate for the first time the feasibility of designing novel molecules that are safe and effective in promoting longevity and preventing multiple age-related diseases in mammals,’’ de Cabo and colleagues wrote in yesterday’s issue of the new journal Scientific Reports.
The drug is one of a set of chemicals designed by Sirtris - a small Cambridge, Mass., pharmaceutical company - to mimic resveratrol, the trace ingredient of red wine thought to activate protective proteins called sirtuins.
The sirtuins help mediate the 30 percent extension of life span enjoyed by mice and rats that are kept on very low-calorie diets. Since few people can keep to such an unappetizing diet, researchers hoped that doses of resveratrol might secure a painless path to significantly greater health and longevity.
But large doses of resveratrol are required to show any effect, so chemical mimics such as SRT-1720 were developed to activate sirtuin at much lower doses.
Sirtuins have proved to be highly interesting proteins, but the goal of extending life span was set back when extensive trials of resveratrol showed it did not prolong mice’s lives, although it seemed to do them no harm.