Scientists identify cause of bone loss in old age

New York: Scientists have identified a mechanism that causes the body to stop creating bone-producing cells with age, a finding that may help develop therapies to treat age-realted bone loss conditions like osteoporosis.

Osteoporosis - the thinning of bone and the loss of bone density that increases the risk of fractures is a major health problem in older people. This is condition is often accompanied by an increase in fat cells in the bone marrow.

Researchers from University of Alabama at Birmingham in the US found that a protein called Cbf-beta plays a critical role in maintaining the bone-producing cells.

Furthermore, examination of aged mice showed dramatically reduced levels of Cbf-beta in bone marrow cells, as compared to younger mice, researchers said.

They found that when this mechanism malfunctions, progenitor cells stop creating bone-producing cells, and instead create fat cells.

Thus, maintaining Cbf-beta may be essential to preventing human age-associated osteoporosis that is due to elevated creation of fat cells, researchers said.

The team detailed an underlying mechanism leading to osteoporosis.

Bone is a living tissue that constantly rebuilds. Bones need a constant new creation of cells specific to their tissue, including the bone-producing cells called osteoblasts. Osteoblasts live only about three months and do not divide, researchers said.

They focused on the molecular mechanism that controls the lineage commitment switch between the osteoblast and adipocyte tracks.

"The knowledge of this mechanism can provide targets in the search for novel bone-loss therapeutics to treat human osteoporosis with minimal side effects," they said.

The study was published in the journal Proceedings of the National Academy of Sciences.