"They will be taking human embryonic stem cells and making them into a kind of support cell in the nervous system and injecting them into the spinal cord lesion," Landis said. "The goal is to determine if this is a safe thing to do. If it turns out there are no adverse events, then they'll plan a larger trial that will look at whether or not this helps the patient."
The main concern with using stem cells directly in therapy is making sure they can be controlled and directed, Srivastava said. For example, doctors want to make sure that cells injected into a spinal cord will form nerve tissue, rather than muscle, skin or bone tissue. There's also a concern that the stem cells could run wild and turn into cancer.
"We need to make sure the transplanted cells do exactly what we want and nothing else," he said.
The U.S. National Institutes of Health has more on stem cells.
SOURCES: Story Landis, Ph.D., director, U.S. National Institute of Neurological Disorders and Stroke, Bethesda, Md.; Deepak Srivastava, M.D., professor, Department of Pediatrics and Department of Biochemistry and Biophysics, University of California, San Francisco, and director, Gladstone Institute of Cardiovascular Disease, San Francisco