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5/10/2001

Stem Cells Show Promise for Stroke Recovery

Kate Traynor

Researchers working with rats report that a transfusion of bone-marrow stromal cells after a stroke improves the animals’ physical symptoms, raising the hope that similar stem-cell therapy could help repair brain injuries in humans.

Compared with controls, rats that received stromal cells one day after an induced stroke scored better on sensory and neurological function tests 14 days after the stroke. Rats that were given stromal cells seven days after a stroke performed better than controls on sensory and motor-skills tests 35 days after the stroke. These animals outperformed controls on neurological functioning tests 21 and 28 days after the stroke, but not on day 35.

The rats used in the study were treated with their own, or autologous, stem cells, which were cultured in the laboratory before the stroke occurred. The finding that therapy could begin seven days after the stroke could be important if the procedure is tried in humans, whose cells would not be available before a stroke.

Another benefit to the therapy was that the cells were injected intravenously, sparing the animals from surgery.

The 32 rats used in the study were given baseline neurologic state assessments and trained to perform specific tasks. Assessments were repeated several times after the stroke, which was induced by temporarily blocking blood flow through the rats’ middle cerebral artery. Twenty rats were given injections of autologous stromal cells one or seven days after the induced stroke, and the other 12 rats served as controls.

According to the report, which appeared in the April issue of Stroke, most of the transfused cells traveled to the injured part of each rat’s brain. The researchers speculated that the stem cells may have directly replaced damaged tissue in the rats’ brains. But a more likely scenario, said the researchers, was that the new cells triggered the repair of brain tissue injured during the stroke.