Aug. 29, 2001 -- Roughly 11,000 new spinal cord injuries occur in the U.S. each year, and more than 250,000 Americans are living with some degree of paralysis due to such injuries. Experts around the globe are working to find ways of repairing traumatic injuries to the spinal cord, and new research from the University of Toronto may bring them one step closer to their goal.
A mystifying problem with spinal cord injuries is their resistance to healing. Peripheral nerves, say in the leg, heal well when cut, but it's the opposite with spinal cord nerves, which do not repair themselves when damaged. UT researchers created a process for making tubes from the same material as that used in disposable contact lenses to fit around the damaged area of the spinal cord and promote nerve regeneration.
While the lead researcher tells WebMD that the studies are very preliminary, the process has shown some success in restoring movement to a small number of paralyzed rats.
"In spinal cord injury you are trying to encourage the nerve fibers to actually grow," Molly Shoichet, PhD, tells WebMD. "The tubes themselves provide a pathway for regeneration. But we also filled the tubes with molecules that help stimulate the nerves to grow within them." Shoichet, who is an associate professor of chemical engineering at the University of Toronto, presented her research at the 222nd national meeting of the American Chemical Society currently underway in Chicago.
Research into spinal cord repair barely existed two decades ago, and in some respects it is still in its infancy, says Susan Howley, director of research for the Christopher Reeve Paralysis Foundation. But she adds that there have been "remarkable strides" made over the past five to 10 years, though there will probably never be a magic bullet approach to preventing and reversing paralysis due to spinal cord injury.
"Essentially, researchers are now looking at a couple of very targeted areas," Howley tells WebMD. "The first is limiting the extent of damage that occurs at the time of injury and in the days and weeks after. They are also working to undo the damage the patient is left with once the acute phase of injury is over."
Only one drug is currently available for limiting the extent of spinal cord damage directly after spinal cord damage. The drug, methylprednisolone, must be given within hours of an injury, and experts continue to debate its usefulness. Howley says better drugs are on the horizon to help minimize spinal damage following accidents. Other researchers are working to reduce the immune system response to spinal injury that contributes to paralysis.
Those like Shoichet and colleagues, who are attempting to reverse nerve damage that has already occurred, face numerous challenges. Even if they are able to get nerves to regenerate, they have to direct the nerves to the right place.
Shoichet's lab created a scaffolding device using mini tubes within bigger tubes to try and solve the direction problem. The scaffolding provides more surface area for nerve regeneration. In the University of Toronto studies, nine rats whose spinal cords had been cut walked somewhat better eight weeks after plastics tube filled with molecules delivering growth factor were implanted.
The researcher says an even newer approach to dispersing growth factor within the tube may help solve the problem of guiding nerve regeneration to where it needs to be. The method has not been tested in animals, but Shoichet says it soon will be.
"What we found in the lab is that if you use a gradient approach so that one end of the tube has a small concentration of growth factor and the other end has a high concentration, it provides a better stimulus for guidance," she said. "We have shown very positive results in the lab."