Researchers have dramatically increased the life spans of mice by genetically engineering them to overproduce a protein called klotho. Not surprisingly, the discovery has spurred speculation that klotho could help humans live longer.
"We overexpressed the klotho gene to suppress aging, and we found that the average life span was 20 to 30 percent longer than in control animals," said pathologist Makoto Kuro-O, of the University of Texas' Southwestern Medical Center in Dallas.
The gene regulates production of klotho protein, which the study team says works like an anti-aging hormone. Kotho is involved in the suppression of insulin-signaling pathways - a process that has been shown to increase the life spans of worms and flies.
"We concluded that the klotho gene is an aging-suppression gene that can extend life span when over expressed and accelerate aging when disrupted," said Kuro-O, who was on the study team, informs Nationalgeographic.
"You have lots of ways to shorten the life of an animal, but it's hard to get an animal to live longer," said George M. Martin of the University of Washington, who is scientific director of the American Federation for Aging Research. "You can kick a radio to make it not work so well, but it's hard to make it work better. It's quite a wonderful discovery."
Kuro-o and his colleagues plan to inject the substance into normal mice to see whether it extends their life spans and to measure the substance in humans to determine whether levels of the protein are correlated with longevity.
Previous research has shown that humans have the protein in their blood, and that people with a certain variation of the gene are prone to age-related diseases such as heart attacks, strokes and osteoporosis.
Scientists will have to determine whether the protein can be produced in sufficient quantities to use it as a drug. It may turn out that other substances that mimic the protein's effects would also work or be safer, Kuro-o said. "That might be more practical," he said, reports MSNBC.