Marrow converted into brain cells.

Last year, biologists found that precursor cells in the brain can act just like bone marrow and give rise to red and white blood cells (SN: 1/23/99, p. 54). In a reversal of that trick, investigators now report that they can efficiently transform human bone marrow into what appear to be nerve cells, or neurons.

Scientists have recently learned that bone marrow has great versatility. The tissue can produce blood, muscle, and liver cells (SN: 3/7/98, p. 150; 7/1/00, p. 7). In the new work, Ira Black of the Robert Wood Johnson Medical School in Piscataway, N.J., and his colleagues developed a broth of growth factors and antioxidants that somehow turns about 80 percent of growing marrow cells into cells that look like neurons.

The transformed cells, in accord with their new appearance, produce many neuron-specific proteins, the team reports in the Aug. 15 JOURNAL OF NEUROSCIENCE RESEARCH. "Any one [protein] can fool you, but when you put them all together, it gets a little difficult to deny [that the cells are neurons]," says Black.

To seal their case, the researchers have begun testing the marrow-derived cells for the electrical activity that defines a neuron. They also plan to see whether transplants of these putative neurons can cure rats with brain disorders that mimic human conditions. They've already found that the cells, when transplanted into the brains and spinal cords of healthy animals, survive and don't harm the animals.

In current research on treatments for spinal cord injuries and illnesses such as Parkinson's disease some scientists depend upon nerve cells grown from brain tissue harvested from aborted embryos or fetuses. Black suggests that bone marrow may offer a richer and less controversial source of nerve cells.