[Boston, MA June 17, 2014]─ Sarcopenia the significant loss of muscle mass and function that can occur as we age is associated with many chronic conditions such as diabetes, high cholesterol and obesity. In findings published online ahead of publication in the September 2014 issue of the FASEB Journal, researchers at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University identify a muscle-building mechanism that could be important in addressing sarcopenia.
When people strength train the body responds by making muscle. The researchers recruited 16 healthy but sedentary men to perform a single bout of resistance exercise to trigger muscle growth and examined tissue samples taken before and six hours after the exercise. Half of the men were in their twenties and the other half in their seventies.
"In order for the body to make proteins that build muscle, certain genes need to be turned on," said lead author Donato A. Rivas, Ph.D., a scientist in the Nutrition, Exercise Physiology and Sarcopenia Laboratory at the USDA HNRCA at Tufts University. "We noticed the older people had a lot fewer genes turned on compared to the younger people, showing us their muscles weren't responding as well to the exercise."
Rivas and colleagues observed that the level of microRNAs, small RNA molecules that have a prominent role in regulating genes, was lower in the muscle tissue of the older men, compared to younger men. "One of the steps in building muscle seems to be missing in the older men, preventing them from responding to the exercise as strongly as the younger men did," Rivas said. "It is possible that the suppression of these microRNAs is setting off a chain of events that is causing older people to be less efficient in developing muscle."
With the population of older adults in the United States projected to increase significantly in the coming decades, more effective sarcopenia treatment and preve
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Tufts University, Health Sciences Campus