'Easter Island' Drug Adds Years to Mice

July 9 -- WEDNESDAY, July 8 (HealthDay News) -- Though researchers aren't ready to recommend that people start popping pills to live longer, they hope a drug used to prevent rejection of transplanted organs may turn out to extend lives, too.

Middle-age mice that were given the drug rapamycin (Sirolimus) lived as much as 38 percent longer than mice that didn't get the drug.

The findings, disclosed in a study released online Wednesday in the journal Nature, provides "a foundation for future research on retarding aging," said the study's lead author, David Harrison, a professor at the Jackson Laboratory in Bar Harbor, Maine.

The mice appeared to do well while taking the drug, but it is unclear if rapamycin would have a similar effect in humans. Also, the drug suppresses the immune system in people, leaving them open to the risk of infection.

"We don't know that the benefits in people at this point will be greater than the deleterious consequences," Harrison said.

Still, the findings appear to represent a step forward in efforts to develop a "longevity pill" that would allow people to live longer.

"It's a really big deal," said pathologist Matt Kaeberlein, who wrote a commentary accompanying the study. "This is the first demonstration of a compound that, when administered late in life, can increase life span in a mammal."

Previously, researchers have shown that greatly limiting food intake in rodents helps them live longer, but that's not a feasible option for many humans who like to eat.

Rapamycin is a compound discovered in the soil on Easter Island, a South Pacific island known for three giant monoliths that have survived for centuries. The name rapamycin is derived from the island's Polynesian name, Rapa Nui.

Today, rapamycin is used to prevent rejection of transplanted organs and to treat some kinds of cancer, said Kaeberlein, an assistant professor of pathology at the University of Washington in Seattle.