Human protein may improve bone growth when injected

An international team of researchers has announced what they believe to be a breakthrough in osteoporosis treatment. Using a naturally occurring protein, scientists say they were able to stimulate bone growth in menopausal laboratory animals.

Their results appeared in a recent issue of the Journal of Bone and Mineral Research. The protein used for the study, interferon gamma, has been under investigation for years as a potential treatment for bone loss.

Interferon gamma is a signalling molecule used by the body's nervous and autoimmune systems. Scientists have determined that the protein helps regulate the immune system and suppress viral and cancerous activity, according to a 2004 report in the Journal of Leukocyte Biology.

Now, researchers from Australia and Canada have determined that injections of the protein may promote bone growth. A similar study conducted in 1994 and published in the Journal of Pediatrics had already found that human interferon gamma therapy appears to relieve the symptoms of a related condition, osteopetrosis.

In the new study, bone health experts injected laboratory mice with interferon gamma and monitored their bone density over time.

All rodents were either menopausal or had undergone an ovariectomy, which is the total removal of the ovaries. In either case, the mice displayed the mineral loss and imbalance between bone-forming and -absorbing cells consistent with the onset of osteoporosis.

The team found that, over time, the injections of interferon gamma were associated with an increase in bone density, as well as with an increase in the activity of osteoblasts, the specialized cells that form bone tissue.

Researchers said that the connection between the protein and bone growth is unclear. They theorized, based on an increasing understanding of the connections between the immune and skeletal systems, that the molecule may inhibit the action of osteoclasts, or the cells that absorbed bone minerals.

The group concluded that interferon gamma has the potential to be a valuable tool in the fight against osteoporosis.

One in three American women over the age of 50 will experience an osteoporosis-related fracture in her lifetime, according to the International Osteoporosis Foundation.