June 7, 2011

Stem Cells May Heal Broken Bones

(Ivanhoe Newswire) -- Each year, approximately 7.9 million bone fractures occur in the United States alone, costing an estimated $70 billion. Of these, 10 to 20 percent fail to heal. However, researchers at the University of North Carolina at Chapel Hill School of Medicine have discovered through an animal study that transplantation of adult stem cells enriched with a bone-regenerating hormone can help mend bone fractures that are not healing properly.

The researchers found that stem cells manufactured with the regenerative hormone insulin-like growth factor (IGF-I) become bone cells and also help the cells within broken bones repair the fracture, which speeds up the healing process. Fractures that do not heal during the normal timeframe are called non-union fractures. The team used an animal model of a non-union fracture, called a "knockout" mouse that lacks the ability to heal broken bones.

They took adult stem cells from bone marrow of mice and engineered the cells to express IGF-I. Then they transplanted the treated cells into "knockout" mice with a fracture of the tibia, the long bone of the leg. The researchers showed through computed tomography scanning, that the treated mice had better fracture healing than did mice either left untreated or treated only with stem cells. The treated mice had more bone bridging the fracture gap, and the new bone was three to four times stronger.

"More excitingly, we found that stem cells empowered with IGF-I restored the formation of a new bone in a mouse lacking the ability to repair broken bones. This is the first evidence that stem cell therapy can address a deficiency of fracture repair," Anna Spagnoli, M.D., the study's team leader and associate professor of pediatrics and biomedical engineering at UNC Chapel Hill, was quoted saying.

The study's discovery "is a crucial step toward developing a stem cell-based treatment for patients with fracture non-unions. I think this treatment will be feasible to start testing in patients in a few years," Spagnoli said.

SOURCE: The Endocrine Society's 93rd Annual Meeting in Boston, Massachusetts, June 5, 2011.