Test Driving Stem Cells

A hundred years ago, the automobile was a mechanical marvel, but it didn't really gain acceptance until there was a support infrastructure in place that included roads, bridges, and gas stations. The same thing could be said for stem cells today. Inducing adult stem cells to transform themselves into specific types of tissue is a remarkable scientific breakthrough, but it is not enough in itself to yield new therapies. That's why work by researchers like Roy Ogle is so important. Ogle is creating the infrastructure needed to harness stem cells to heal bone fractures and regenerate nerves.

Ogle taps all the techniques of tissue engineering. For instance, in an effort to regenerate sciatic nerves, he is trying out a variety of adult stem cells. These include those extracted from fat tissue by his colleague Dr. Adam Katz as well as stem cells he and M.D./Ph.D. student Sunil Tholpady have identified in the lining of the brain and spinal cord. In addition, he is exploring the different kinds of materials that can be used to create a matrix to hold and organize these cells. He adds small pieces of proteins to these polymers to serve as adhesion sites for the new cells. Ogle is also experimenting with combinations of growth factors and other substances needed to induce adult stem cells to follow a desired developmental path.

"Stem cell research has led to the most exciting advances in biomedical discovery that I have witnessed," he says. "I can't think of a disease or a disorder that doesn't lend itself to stem cell intervention."

Ogle and his colleagues have found that each line of adult stem cells has an inherent phenotype. In effect, it is prone to be converted to one particular cell type rather than another. Ogle has found that adult stem cells derived from fat can be converted to nerve cells in just 24 hours, while it takes two weeks to convert them into bone and cartilage and even longer to induce them to become muscle cells.

This is a limitation in comparison with embryonic stem cells, which are more readily plastic and easily converted to a wide range of cell types. On the other hand, the limitations of adult stem cells increase their potential utility in specific cases. If you are interested in producing high yields of nerve cells, you are much better starting from a fat stem cell than an embryonic one.

Ogle is excited by the prospects for stem cell research at U.Va. "We are a medium-sized school," he points out, "and we can't be a leader in everything. But with a little luck and careful planning, we can be a world leader in this field."