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The newspaper of The Johns Hopkins University February 19, 2007 | Vol. 36 No. 22
Human Stem Cell Transplants Grow, Make Contact in Rat Spinal Cord

By Audrey Huang
Johns Hopkins Medicine

Human nerve stem cells transplanted into rats' damaged spinal cords have survived, grown and in some cases connected with the rats' own spinal cord cells in a Johns Hopkins laboratory, overturning the long-held notion that spinal cords won't allow nerve repair.

A report on the experiments, published online last week at PLoS Medicine, "establishes a new doctrine for regenerative neuroscience," said Vassilis Koliatsos, associate professor of neuropathology at Johns Hopkins. "The spinal cord, a part of the nervous system that is thought of as incapable of repairing itself, can support the development of transplanted cells.

"We're still in the proof-of-concept stage," he said, "but we're making progress, and we're encouraged. We don't yet know whether the connections we've seen can transmit nerve signals to the degree that a rat could be made to walk again."

In their experiments, the scientists gave anesthetized rats a range of spinal cord injuries to lesion or kill motor neurons, or performed sham surgeries. They varied experimental conditions to see if the presence or absence of spinal cord lesions had an effect on the survival and maturation of human stem cell grafts. Two weeks after lesion or sham surgery, they injected human neural stem cells into the left side of each rat's spinal cord.

After six months, the team found more than three times the number of human cells than they had injected in the damaged cords, meaning that the transplanted cells not only survived but divided at least twice to form more cells. Moreover, Koliatsos said, the cells not only grew in the area around the original injection but also migrated over a much larger spinal cord territory.

Three months after injection, the researchers found evidence that some of the transplanted cells had developed into support cells rather than nerve cells, while the majority became mature nerve cells. High-powered microscopic examination showed that these nerve cells appear to have made contacts with the rat's own spinal cord cells.

The research was funded by the National Institute of Neurological Disorders and Stroke, the Muscular Dystrophy Association and the Robert Packard Center for ALS Research at Johns Hopkins.

Authors on the paper are Jun Yan, Leyan Xu, Annie M. Welsh, Glen Hatfield and Koliatsos, all of Johns Hopkins; and Thomas Hazel and Karl Johe of Neuralstem, Rockville, Md.


Related Web sites

Vassilis Koliatsos
'PloS Medicine'
JHU Division of Neuropathy


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