US: Remove bone marrow to speed bone healing

American scientists have shown that recovery from bone breaks can be significantly increased - strangely by taking out the damaged bone's marrow.

A team at Yale University School of Medicine, in Connecticut, performed a study on rats whereby the bone marrow, the spongy material inside the bones that produces stem cells, was removed from a fractured bone. This was followed with daily doses of parathyroid hormone (PTH), a drug that encourages the growth of new bone material.

The researchers saw dramatic improvements in the time it took for the fracture to heal without the marrow. They discovered that, in fact, the de-marrowed thighbones of the PTH-treated rats encouraged healing whereas the bone marrow left in the bone appeared to inhibit broken bones' healing process.

"This could radically change the way patients are currently treated for weakened or fractured hips, vertebrae and acute traumatic long bone fractures," said senior author Dr Agnes Vignery, an associate professor of orthopaedics at Yale.

Vignery said current available treatment required surgery and artificial materials and often resulted in imperfect outcomes. "The ideal approach would be to create new bone where it is needed and at a faster rate," she said.

Although bone marrow stem cells are needed to produce blood cells, Vignery explained that people's health should not be affected by the removal of marrow in one bone as long as it remained intact in other bones.

Warren Levy of Unigene Laboratories, which provided the scientists with the PTH, believes this discovery will particularly change the way elderly patients requiring life-threatening surgery will be treated: "Instead, if an X-ray reveals a fracture, you could go in with a needle right there in the doctor's suite and do without surgery," Levy said in a report published in New Scientist.

So far, the procedure has been tested in small rodents but plans are in place to next test on rabbits before finally moving to human clinical trials.

monica.dobie@uw-news.com