Scientists at the University of Pennsylvania Medical Center have developed a novel gene therapy treatment that permanently blocks the age-related loss of muscle size and strength in mice. Mice, like humans and all mammals, lose up to a third of their muscle mass and power with age. In humans, the result is an advancing weakness in the elderly that can lead to unsteadiness and impaired mobility, increased susceptibility to falls and injury, and joint stress and degeneration.
Even in young adult mice, the new treatment increased muscle strength by a dramatic 15 percent over untreated muscle. But in older mice, the improvement was even more remarkable: The researchers documented a 27 percent increase in strength over untreated muscle in these mice -- fully restoring their strength to what it was in young adulthood.
The technique suggests human therapies that could reverse the feebleness associated with old age or counter the muscle-wasting effects of muscular dystrophies and related diseases. It also raises the possibility, however, that the technique could be used -- or abused -- for athletic or cosmetic enhancements.
Results from the experimental study will be presented at the 38th annual meeting of the American Society for Cell Biology in San Francisco on December 14 and will be published in the December 22 issue of the Proceedings of the National Academy of Sciences. (Copies of the paper are available to reporters through the journal's news office, reachable by telephone at 202-334-2138 or by e-mail at firstname.lastname@example.org.)
"Our results show that it may be possible to preserve muscle size and strength in old age using this approach," says H. Lee Sweeney, PhD, professor of physiology and senior investigator on the study. "We're now looking to see whether the technique might also be used to increase muscle strength in diseases such as muscular dystrophy."