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Health Team

Stem cells could help heal broken bones

Posted June 19, 2008 6:22 p.m. EDT
Updated June 19, 2008 10:42 p.m. EDT

— Research at UNC Hospitals has produced promising results for the hundreds of thousands of Americans who have bone fractures that wil not heal.

An estimated 600,000 people suffer from unhealed bone fractures, which are a major cause of disability. Osteoporosis is the major culprit for women in that group because it can cause tiny, unhealed fractures in their spines.

Existing treatments for unhealed bone fractures often require surgery, bone grafts or prosthetic materials that never fully integrate with bones.

Ashely Wright, of Durham, has pursued traditional treatments since back problems led her to get a bone-density scan 10 years ago.

"What the doctor told me was that my bones were at least twice as old as the rest of me," Wright said. "There's so many small fractures you get with osteoporosis, little spinal fractures that you're not even aware of."

To help prevent the spread of osteoporosis and bone fractures, "Exercise is almost my full-time job," Wright said.

Results from a UNC lab, though, offer hope for people like Wright.

In studies of mice, UNC researcher Dr. Anna Spagnoli claims to have found a way to deliver bone-building stem cells to a fracture site.

"Three days after the fracture, the cells migrated to the fracture site. They didn't go to any other place, just went to the fracture site," Spagnoli said.

Spagnoli used adult stem cells from bone marrow and added a special molecule, similar to the one that makes fireflies glow, to allow her to see stem-cell activity.

A growth factor called IGF1 steered the stem cells into becoming bone cartilage – the glue that begins the bone healing process. Another molecular factor delivered the stem cells to the broken bone.

"The mice that received the stem cells with IGF1 had more healing tissue, had more cartilage,  had more bone," Spagnoli said.

Clinical human trials of the method will take at least two years to begin.