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
"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
"The more we learn about these types of changes, the more we may be able
to help patients in the future," Vilayanur S. Ramachandran, MD, PhD, tells
WebMD. "These findings are equally applicable to treatment of spinal cord
injury and brain injury." Ramachandran is professor and director of the
Center for Brain and Cognition at the University of California, San Diego.
Jain agrees that this research might eventually lead to new treatment
approaches in spinal cord injury and stroke. "Even without intervention,
the brain is capable of this kind of growth," he says. Perhaps we could
encourage remodeling of the brain to allow healthy parts of the brain to take
over functions ordinarily assumed by impaired areas."