January 14, 2015

Inner ear keeps bones strong

Alterations of the vestibular system – the part of our inner ear that controls balance – may contribute to bone loss related to both aging and space travel.

Vanderbilt Center for Bone Biology researchers, led by Florent Elefteriou, Ph.D., and Guillaume Vignaux, Ph.D., have discovered that a functional vestibular system – the part of our inner ear that controls balance – is critical to maintaining bone strength in mice.

Osteoblasts and osteoclasts (bone building and resorbing cells, respectively) maintain our skeleton in a finely tuned state through constant remodeling. In mouse models, the researchers found that bilateral loss of vestibular output resulted in increased sympathetic outflow – signals from the body’s “fight or flight” nervous system. This increased sympathetic activity ultimately led to a loss of lower extremity bone integrity through decreased osteoblastic and increased osteoclastic activity.

The research suggests that alterations of the vestibular system – because of aging or in the zero-gravity setting of outer space – might contribute to age-related bone loss and to the bone loss astronauts suffer during prolonged voyages.

The findings, reported in the Journal of Bone and Mineral Research, open the door for future studies of therapeutics that may combat bone loss both on and off earth.

This research was supported by the National Aeronautics and Space Administration, the National Space Biomedical Research Institute and the National Institutes of Health (grant RR027631).

Send suggestions for articles to highlight in Aliquots and any other feedback about the column to aliquots@vanderbilt.edu