Michael Fehlings, MD, PhD, and his colleagues at the Krembil Neuroscience Center at Toronto Western Research Institute and the University of Toronto also identified a critical window during which stem cell transplants may be effective, says the study, which appears in the March 29 issue of The Journal of Neuroscience.
"This work breaks new ground by showing that therapeutically useful stem cells can be derived from the adult brain of rodents, and that these cells can be caused to differentiate into the types of cells that are useful for repairing the damaged spinal cord," says Oswald Steward, PhD, director of the Reeve-Irvine Research Center for Spinal Cord Injury at the University of California, Irvine.
Fehlings' team used cells from the brains of adult mice labeled with a fluorescent marker, enabling them to trace the cells after they were transplanted into rats whose spines had been crushed. Stem cells transplanted up to two weeks after the initial injury survived thanks to a cocktail of growth factors and immune-suppressing drugs the team developed. More than one-third of the transplanted cells traveled along the spinal cord, were incorporated into damaged tissue, developed into the type of cell destroyed at the injured site, and produced myelin, an insulating layer around nerve fibers that transmits signals from the brain.
An injured spinal cord loses its ability to regenerate myelin-forming cells, leading to paralysis. Fehlings showed that where stem cells restored myelin in the injured spine, rats showed some recovery and walked with more coordination.
One new aspect demonstrated by the study is that "the maximal effect of transplanting these cells is early after injury,
Contact: Sara Harris
Society for Neuroscience