About 10,000 people in the United States suffer spinal cord injuries each year. Studies in animals during the past decade have shown that supporting cells from nerves outside the brain and spinal cord, called Schwann cells, can be used to make a "bridge" across the damaged spinal cord that encourages nerve fibers to regrow. Other research has suggested that a substance called cyclic AMP (cyclic adenosine monophosphate) can turn on growth factor genes in nerve cells, stimulating growth and helping to overcome signals that normally inhibit regeneration. This study is the first to try a combination of the two approaches in an animal model of spinal cord injury.
In the new study, Mary Bartlett Bunge, Ph.D., Damien Pearse, Ph.D., and colleagues at the Miami Project to Cure Paralysis at the University of Miami School of Medicine, found that spinal cord injury triggers a loss of cAMP in the spinal cord and in some parts of the brain. They then transplanted Schwann cells into the spinal cords of rats in a way that bridged the damaged area. The researchers also gave the rats a form of cAMP and a drug called rolipram, which prevents cAMP from being broken down.
Treatment with the triple-combination therapy preserved and even elevated cAMP levels in nerve cells after injury. It also preserved many of the myelinated nerve fibers in treated animals, compared to untreated rats and those that did not receive the triple combination, the researchers found. Myelin is a fatty substance that insulates the nerve fibers and
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NIH/National Institute of Neurological Disorders and Stroke