Compound extends lifespan by a third

Posted by Emma Woollacott

San Antonio, Texas - Those who believe the Easter Island statues were created by supermen could have a field day with this. It seems a compound found in the island's soil has significant life-extending properties.

According to findings from the University of Texas Health Science Center and others, the Easter Island compound – called "rapamycin" after the island's Polynesian name, Rapa Nui – extended the lifespan of middle-aged mice by 28 to 38 percent. The rapamycin was given to the mice at an age equivalent to 60 years old in humans.

"I've been in aging research for 35 years and there have been many so-called 'anti-aging' interventions over those years that were never successful," said Dr Arlan G Richardson, director of the Barshop Institute. "I never thought we would find an anti-aging pill for people in my lifetime; however, rapamycin shows a great deal of promise to do just that."

Discovered in the 1970s, rapamycin was first noted for its anti-fungal properties and was later used to prevent organ rejection in transplant patients. It is also used in stents, and is in clinical trials for the treatment of cancer. It has one big problem for real-life use, though, which is that it suppresses the immune system.

Aging researchers currently acknowledge only two life-extending interventions in mammals: calorie restriction and genetic manipulation. Rapamycin appears to partially shut down the same molecular pathway as restricting food intake or reducing growth factors. It does so through a cellular protein called mTOR (mammalian target of rapamycin), which controls many processes in cell metabolism and responses to stress.

The original goal was to begin feeding the mice at four months of age, but because of a delay caused by developing a new formulation, the mice were not started until they were 20 months old – the equivalent of 60 in humans. The teams decided to try anyway.

"I did not think that it would work because the mice were too old when the treatment was started," Dr Richardson said. "The fact that rapamycin increases lifespan in relatively old mice was totally unexpected."

The findings are published in Nature.