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Mouse may hold secret of ages

Scientists are celebrating the birthday of the world's oldest known living mouse, a dwarf mouse named Yoda, who turned four - roughly 136 in human years - on Saturday.

And Yoda may yield some clues to longevity.

The average life span of a laboratory mouse is just over two years. Other mice have fallen just short of the five-year mark, but Yoda is the first to make it to four years on a diet that was not calorically restricted.

"It would amaze me if he survived more than another six months, but we can always hope," said Richard Miller, associate director of the geriatric centre at the University of Michigan Medical School, where Yoda was raised. "We don't want to jinx him."

Although Yoda is not a calorie counter, he, like other dwarf mice, has a genetic mutation that chokes off production of growth and thyroid hormones.

Dwarf mice tend to grow to only about a third the size of normal mice, which helps them live about 40 per cent longer.

They can avoid the diseases of old age until extremely late in life. While another mouse might have reached old age and developed arthritis or cancer, a dwarf mouse born at the same time might still be in the equivalent of middle-aged good health.
By studying hormonal changes in dwarf mice, scientists might be able to slow the ageing process in humans as well, Dr Miller said.

"The . . . idea is to find out what the key controlling chemicals are so the problems people see now in their 60s or 70s could be delayed for another 20 or 30 years," he said.

Posted by thinkum at April 13, 2004 02:12 PM