Individuals who are paralyzed due to spinal cord injury have little hope of being able to walk again. Two new studies, however, raise hopes that it may some day be possible to restore movement by coaxing the regeneration of nerves within the central nervous system.
In the first study, British and German researchers identified a chemical mechanism by which they were able to stimulate the re-growth of damaged nerve fibers in the central nervous system, or CNS, of mice. They found that a protein called PCAF appears to be essential for nerve regeneration after studying peripheral nerves in cell culture. The peripheral nervous system is involved in sensation and some muscle movement outside the CNS.
Damaged axons in the central nervous system make no effort at repair, but experts say about 30 percent of damaged peripheral nerves regenerate, in many cases partially restoring function. The PCAF protein signals a series of chemical and so-called epigenetic events that promote the re-growth of these nerves. Epigenetic processes do not alter DNA.
Scientists injected PCAF into mice with damaged spinal cords. They describe in an article in Nature Communications how the protein switched on a repair mechanism, causing new CNS nerve fibers to sprout.
Lead researcher Simone Di Giovanni of Imperial College London’s Department of Medicine says the next step is to see whether the mice are able to move following treatment. Di Giovanni says researchers would like to find compounds that can be given to people with spinal cord injuries.
“…to see whether specific drugs can enhance functional recovery and promote nerve growth by fortifying this epigenetic mechanism that we have identified," said Di Giovanni.
Meanwhile, researchers at King’s College London describe how they injected a single shot of scar-busting gene therapy into the injured spinal cords of rats. The enzyme, called chondroitinase ABC, digested scar-forming proteins at the lesion site. Scar tissue can prevent damaged nerves from re-growing.
In The Journal of Neuroscience, researchers report how, within weeks, the gene therapy promoted the survival of nerve cells and improved the rats’ hind limb function, offering hope that the therapy could one day treat people with spinal cord injuries.