BY SETH BORENSTEIN,
AP Science Writer
WASHINGTON—A drug used to prevent the rejection of organ transplants was found to significantly increase the life span of older mice, U.S. researchers report.
The National Institute on Aging is testing compounds that may extend the life span of mice. The drug rapamycin is the first to work for both male and female mice, according to a study published online in the journal Nature.
The drug could not be used for that purpose in people. It suppresses the human immune system to prevent a transplant recipient's body from attacking the donated tissues, raising the odds of disease.
Researchers did not start the medicine on the mice until they were about 600 days old, the equivalent of about 60 years for people. Despite that delay, the rapamycin seemed to work, said lead author David Harrison of the Jackson Laboratory in Bar Harbor, Maine.
That surprised and impressed gerontologist George Martin at the University of Washington, who was not part of the study.
Females fed rapamycin lived 14 percent longer than those that didn't take the drug. For males, it was 9 percent longer.
Randy Strong, a study co-author and professor of pharmacology at the University of Texas Health Science Center in San Antonio, said it is the equivalent of adding six extra years of life to men and eight years for women.
Rapamycin already extended life for yeast, worms and fruit flies.
"This is most promising," said Nancy Nadon, of the National Institute on Aging and another study co-author. She said the key is to find other compounds that target the same cellular pathway without the harmful side effects of rapamycin.
Earlier studies showed that resveratrol, which is in red wine, extended the life of obese mice. Unlike resveratrol, rapamycin worked on normal size mice of both genders, Harrison said.
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On the Net:
Nature: http://www.nature.com/nature
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