A new study shows that adult stem cells encased in a spongy matrix can be used to fill in large gaps in bones, providing a potential alternative to bone grafts. Georgia Tech researchers tested the method in rats with large bone gaps, to simulate massive injuries. Bone marrow-derived mesenchymal adult stem cells or amniotic fluid stem cells were tested. Eight weeks after the treatment, new bone bridged the gaps in four of nine defects treated with scaffolds seeded with adult stem cells, one of nine defects in the amniotic stem cell group, and none of the defects in rats treated with the scaffold alone.

According to lead author Robert Guldberg:

"Massive bone injuries are among the most challenging problems that orthopedic surgeons face, and they are commonly seen as a result of accidents as well as in soldiers returning from war. This study shows that there is promise in treating these injuries by delivering stem cells to the injury site. These are injuries that would not heal without significant medical intervention."

The results, published in the Proceedings of the National Academy of Sciences, also indicated that adult stem cells are shy about being watched while they work. In an attempt to track the stem cells, some experiments used cells labeled with fluorescent quantum dots. In those experiments, the researchers found that the cells showed lower therapeutic benefit.

Previously researchers have had good success with smaller bone breaks in patients, even with non-healing injuries, using adult stem cells.