New Research May Aid Future Treatments for Spinal Cord Injury
April 26, 2000 -- Injured nerve cells can't grow back. Or can they?
For years, scientists have thought that nerve cells in the brain and spinal cord of adult humans have very limited capacity to regenerate, or grow back, after injury. But now, new research suggests that healthy brain cells can grow into new areas of the brain, taking over the function of nerve cells that are no longer functioning normally.
According to data from the University of Alabama National Spinal Cord Injury Statistical Center, there are approximately 250,000 people with spinal cord injuries in the U.S., with approximately 11,000 new injuries occurring each year. Developing effective treatments and preventing new injuries could save the U.S. up to $400 billion on future direct and indirect lifetime costs related to these injuries.
More than half of spinal cord injuries occur in young adults aged 16 to 30 years, and almost three-quarters occur in males. About 90% of the people with spinal cord injuries survive, and have near-normal life spans.
In the new study, monkeys with a spinal cord injury that caused loss of feeling in their arms had extensive new growth of nerve fibers in the brainstem -- the lower part of the brain connecting the spinal cord to higher brain centers. The brainstem is small -- about as thick as a Magic Marker -- but very densely packed with nerve cells and fibers carrying sensory information from the body to the brain. The growth of even a few new fibers in the brainstem can have far-reaching effects on how nerve cells in the brain are reorganized.
"For the first time, we have shown that growth can span ... distinct groups of nerve cells in the brainstem," Neeraj Jain, PhD, tells WebMD. He is lead researcher of the study, which was sponsored by the Christopher Reeve Paralysis Foundation and the National Institutes of Health and reported in the April 25 issue of the journal Proceedings of the National Academy of Sciences.
"This type of large-scale growth across the primate brain has not been seen before," says Jain, who is also assistant professor of psychology at Vanderbilt University in Nashville, Tenn. These findings suggest that the adult brain and spinal cord may be more capable of regeneration than previously believed.