Mighty mice hold hope for muscle ailments

Sweeney with a few of his muscular mice

Photo by Daniel R. Burke

Broad shoulders. Sculpted muscles. An almost unnatural resistance to aging. No, it’s not the former Terminator-turned-Governor of California, Arnold Schwarzenegger, but the legion of mice running about the Richards Labs hoping to chart a path toward greater quality of life for sufferers of muscular dystrophy and aging alike.

You may have heard of these wonder mice before—they have been on campus for a number of years as the subjects of research directed by Lee Sweeney, chairman of Physiology, who has made remarkable progress in the study of muscle health through enhanced muscle growth and repair.

The research, first published in 1998, is the study of a synthetic gene, Insulin Growth Factor-1 and its effect on muscle health. Created by Sweeney and his team, IGF alerts muscles to the need for repair and growth, boosting the amount of protein in the muscles, thus affecting growth, and stimulating outside cells to increase repair. The synthetic gene is introduced into the subject via a recombinant virus, which is a highly effective vehicle for infecting cells without the negative effects commonly associated with viruses.

The results of the research have been somewhat surprising, even for Sweeney. “Of course we wouldn’t have tried it if we didn’t know something would happen,” he remarked. “But in the older mice it was surprising how well the muscle mass was maintained.”

The mice in question, some of whom have reached the equivalent of human age 80, have retained the muscle mass and health of their much younger relatives. (Mice and humans age in similar fashion physiologically.) Aside from strength and greater mobility, the retention of muscle mass means a lot to both mice and humans as they age. Muscle mass greatly affects the metabolic state and helps to keep the immune system balanced.

Unfortunately, Sweeney’s desire to improve the lives of those who suffer from muscle disease and the inevitable toll of aging has been brought into the public forum on less noble grounds, as many consider the possible abuse of such scientific breakthroughs in the field of sport.

Imagine a world-class athlete’s enhanced capabilities and longevity in sport with such a boost. Many governing bodies already have, and have sought the advice of Sweeney and his colleagues in detecting the next great wave of sports doping. He admitted that the testing would be much more difficult. “Sampling blood and urine won’t do it.”

However, for Sweeney and for those that suffer the trauma of muscle disease, the world of sport is a “small footnote” to the great benefits that are to come worldwide. “It is the quality of life that we are most interested in. The ethical issue is black and white. If it is safe, then it’s a no-brainer.”

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Originally published on December 11, 2003