June 21, 2008

Technology Might Rebuild Bone Tissue

CHAPEL HILL, N.C. - Medical researchers at University of North Carolina-Chapel Hill announced Monday that they have made strides in the technology to rebuild damaged bone tissue using stem cells.

The research team, led by Dr. Anna Spagnoli, an associate professor of pediatrics at the university, derived the stem cells from bone marrow samples to locate and repair broken bones in mice. Now the work is poised to move to humans.

"What we have done here is shown a reason to move to a real clinical trial," Dr. Spagnoli said.

Twenty percent of broken bones cannot heal on their own, which affects 600,000 people in the United States each year. A significant portion of them are women who suffer from osteoporosis, but the problem is not restricted to older patients. Children diagnosed with a condition known as brittle bone disease can suffer from multiple, painful fractures over their lifetimes.

Stem cell technology could significantly reduce healing time, Dr. Spagnoli said.

It's a field that is generating interest, and possibilities. A recent case in Germany, in which a man lost his jaw to an aggressive tumor, was reported in the journal Lancet in 2004. In that instance, German scientists used a titanium jaw prosthesis as a scaffold in which they planted stem cells extracted from the patient's bone marrow. The scaffold served as a mold for a new jawbone to grow from the cells.

The University of North Carolina study coaxed the stem cells to become cartilage using a compound called a growth factor.

"The first step in bone healing is to create cartilage as a glue," Dr. Spagnoli said. "Without that glue, the bone will not be able to heal."

Creating cartilage is not enough to fix a broken bone. The cartilage glue needs to form at the fracture for it to heal properly.

Dr. Spagnoli's team noticed that a certain molecule in the stem cells was the key to homing in on the fracture. The molecule, called CXR4, was responding to a chemical signal sent out by the damaged bone.

"It's like the fracture is sending out a message that says 'please come here, there is help needed here,'" she said.

Originally published by McClatchy Newspapers.

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