Harvard team reverses aging in mice

Posted by Emma Woollacott

Researchers at Harvard Medical School have found an elixir of youth - for mice, at any rate.

The team succeeded not only in halting the ageing process, but in actually reversing it. Their treatment turned prematurely-aged mice into energetic young ones, even reversing brain disease and infertility.

Telomeres are protective caps that shield the ends of chromosomes. As humans age, the telomeres are progressively eroded, contributing to signs of ageing.

"We wanted to know: If you could flip the telomerase switch on and restore telomeres in animals with entrenched age-related disease, what would happen?" says senior author Ronald DePinho. "Would it slow down aging, stabilize it, or even reverse it?"

The team bred genetically manipulated mice that lacked an enzyme, telomerase, that protects the telomeres from the shortening process. The mice showed premature symptoms of ageing such as a poor sense of smell, infertility and organ damage.

But after a month of injections to reactivate telomerase, the signs of ageing disappeared and the animals even started growing more neurons in their brains.

DePinho says the research could have implications for people suffering from premature ageing syndromes.

"Whether this would impact on normal aging is a more difficult question," he says. "But it is notable that telomere loss is associated with age-associated disorders and thus restoration of telomeres could alleviate such decline."

Unfortunately for humans, while mice continue to produce telomerase throughout their lives, the ability to produce it is switched off in people after puberty. Because of its ability to increase cell production, it fuels any cancers that might be present.

This is a pretty fundamental handicap to any search for a fountain of youth. However, DePinho said that none of the mice in the study developed cancer, and suggested that a telomerase treatment could perhaps be made safe by using it only for short periods.

The research appears in Nature.