Anti-Rejection Drug May Extend Human Life

July 10, 2009 4:35 p.m. EST

Washington, D.C. (AHN) - A drug used to alleviate the rejection of organ transplants may someday add extra years to the human lifespan.

Researchers have found that mice given the anti-rejection drug rapamycin lived significantly longer than those that weren't.

The study, published this week in the journal Science, found that female mice lived 13 percent longer and male mice 9 percent longer.

The drug was not administered until the mice were about 600 days old, equal to about 60 years in humans.

The research involved about 2,000 genetically similar mice. Conducted at three test sites around the country, the study was part of the National Institute of Aging Interventions Testing Program.

How the drug works is still not clear.

Researchers cautioned against taking rapamycin for life extension at the moment. The drug suppresses the body's immune system, which could lead to infections.

The drug also is being studied as a cancer vaccine and as a treatment for a form of mental retardation caused by disease.

Other possible uses are being studied, noted Randy Strong, a pharmacology professor at the University of Texas Health Science Center at San Antonio and one of three lead authors of the study. "I think more immediately, people are starting to look at [rapamycin] for age-related diseases like Alzheimer's disease, Parkinson's disease or kidney disease," he told Time magazine.

The drug, known generically as sirolimus, was discovered about 40 years ago. It was derived from a soil fungus found on Easter Island, also known as Rapa Nui. Easter Island is best known for its large stone sculptures called moa.