by Jason P. Smith
A recent study conducted by researchers at Penn State University College of Medicine possibly could bear some good news for the fight against osteoporosis.
In an effort to help people suffering from osteoporosis, a disease characterized by low bone mass and structural deterioration of bone tissue that leads to bone fragility and an increased susceptibility to fractures, researchers analyzed blood samples from black bears hibernating in Virginia. The researchers found that the bears, although inactive for long periods of time, did not experience profound bone loss.
In humans bone regeneration slows or stops during prolonged periods of inactivity brought on by disease or injury, but this was found to not be the case with black bears. The researchers now want to determine why bears continue to regenerate bone and look for ways to simulate that process in humans.
According to the researchers, these findings raise the possibility that hibernating black bears may minimize bone loss during disuse by maintaining osteoblastic function. It also shows they may have a more efficient mechanism for recovering immobilization-induced bone loss than that of humans or other animals. The researchers hope to find what molecule the bears have that makes them resistant to osteoporosis and then try to use that molecule in the fight against osteoporosis in humans.
The study, which is in the March issue of the journal Clinical Orthopedics and Related Research, was done by Henry J. Donahue, a professor of orthopedics and rehabilitation at Penn State University College of Medicine in Hershey, and Seth Donahue, assistant professor of biomedical engineering at Michigan Technological University.
Seth Donahue said the study did not determine exactly why bears continue to regenerate bone. But he suspects a hormone or other chemical might be responsible, and the Donahues, who are not related, hope to do follow-up studies to test that hypothesis. The research done by the two professors possibly could help alleviate a serious public health threat.
According to the National Osteoporosis Foundation, in the United States today approximately 10 million individuals are estimated to already have the disease and almost 34 million more are estimated to have low bone mass, placing them at increased risk for osteoporosis. Statistics also show that 55 percent of the people 50 years of age and older, having low bone mass, which puts them at increased risk of developing osteoporosis and related fractures. Osteoporosis is responsible for more than 1.5 million fractures annually, according to the National Osteoporosis Foundation.
Of the 10 million Americans estimated to currently have osteoporosis, eight million are women and two million are men. Often called the silent disease, osteoporosis occurs without any noticeable symptoms. In fact, women can lose up to 20 percent of their bone mass in the five to seven years following menopause, making them more susceptible to osteoporosis.
Not only is the number of people who suffer from this disease high, but the estimated national direct expenditures for hospitals and nursing homes for osteoporotic and associated fractures also is very high. In 2001 it was $17 billion, which breaks down to $47 million each day.