Building a Bridge to Reverse Paralysis
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."