The more you exercise, the stronger your bones get

Washington D.C.: You may want to start hitting the gym as a recent study suggests that exercise-induced hormone irisin may have a therapeutic potential in strengthening bone.

The Tufts University School of Dental Medicine (TUSDM) study, published in Bone Research, found that two weeks of voluntary wheel running induces higher expression of irisin.

In addition, systemic administration of irisin increased bone formation and thickness, mimicking the effects of exercise on the mouse skeletal system. The findings demonstrate a potential new mechanism for the regulation of bone metabolism.

"Our results provide insight into the complex regulatory interplay of muscle, bone and fat tissues. Increased irisin levels in circulation upon systemic administration can recapitulate part of the beneficial effects of exercise in the skeletal system," said senior author Jake Chen. "Further experimentation will be needed to evaluate the involvement of irisin and other factors increased by exercise and expressed by bone, muscle and fat tissue."

The team's findings demonstrate that irisin produced by bone could have a role in bone metabolism through both direct mechanisms and indirect mechanisms, as the transition from white fat to brown fat has been shown to lead to increased bone formation by previous studies. In addition, recombinant irisin has also been shown to suppress sclerostin, a protein that is involved in bone loss during prolonged lack of mechanical load, such as in bed-ridden patients.

"Exercise-induced irisin may not only act as an endocrine factor capable of promoting the browning of white adipose tissue, but could also regulate bone metabolism by autocrine mechanisms," said Chen. "Our results suggest that irisin may have a therapeutic potential in strengthening bone in bone-loss-associated diseases, and additional studies are needed to evaluate the underlying mechanisms by which irisin functions."