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New hope for repairing spinal injuries Copyright © 1998 Nando.net/Copyright © 1998 The Associated Press LOS ANGELES (May 18, 1998 6:08 p.m. EDT http://www.nando.net) -- Brain-damaged rats that were given injections of an experimental treatment grew new nerve fibers that once again let them climb ropes, grasp food pellets and remove sticky tape from their front paws, scientists reported Monday. Experts said the research could help lead to new approaches to spinal cord and brain injuries in humans. These injuries are particularly devastating because damaged nerve fibers in adults do not regenerate on their own. The growth of new nerve fibers in the rats enabled them to recover their ability to function to "an amazing degree," said Martin Schwab of the Institute for Brain Research at the University of Zurich in Switzerland. "If you test these animals for hand function, precision movements you find a recovery of the behavior which is almost 100 percent." The study by Schwab and his colleagues at the University of Zurich appears in the June issue of the journal Nature Neuroscience. The researchers first cut through nerve fibers in a small area of the rats' brainstem, where the upper part of the spinal cord joins the front of the brain. That knocked out fine motor control of the animals' front limbs. In humans, that area controls such movements as typing on a keyboard. Regeneration of brain and spinal cord nerves is naturally inhibited by proteins in the protective sheaths of the nerve fibers. So Schwab and his colleagues devised an approach to neutralize the proteins with a specially engineered antibody, called IN-1. Mice injected with the antibody sprouted healthy, new nerve fibers in undamaged regions of their brains and spinal cords that took over for the damaged ones. The nerves sprouted and built new connections "which automatically seem to be the right connections," Schwab said. The damaged fibers also showed some regeneration. The ability of the antibody to promote new compensatory growth, rather than just repair damaged nerve fibers, could be useful in treating stroke, the researchers said. Strokes tend to damage one side of the brain only. The human central nervous system contains growth inhibitors similar to those found in the rat. Schwab already is collaborating with a large biotechnology company to neutralize them with antibodies. "It's an important and interesting study," said Michael Beattie, a neuroscience professor at Ohio State University who specializes in spinal cord injury and regeneration. He called Schwab's results "very encouraging." "This study re-emphasizes the role of the non-injured nervous system in compensating for the loss of function after damage," he said. "The work they've done suggests that they're on the right track to understanding how to produce therapies that can enhance repair and recovery of function." Others were more cautious. In an accompanying editorial, journal editor Charles Jennings said it is difficult to know if animal results with IN-1 will speed up progress in spinal cord repair: "The new findings suggest that the picture is not likely to be simple." By JANE E. ALLEN, AP Science Writer -- Judith Richards, London, Ontario, Canada [log in to unmask]