TRANSPLANTS TO RESTORE FUNCTION
TO DENERVATED MUSCLE
Christine K. Thomas, Ph.D. • Patrick M. Wood, Ph.D.

Special nerve cells (motoneurons) within the spinal cord receive signals from the brain and the body. These motoneurons relay the signals to muscles, telling them to contract. When motoneurons die due to disease or injury, some muscles are deprived of their nerve supply (denervation). The muscles are no longer under the person’s control and they waste away (atrophy).

A strategy to restore some function to these muscles is to replace the cells in the nerve near the influenced muscles. In previous studies, Dr. Thomas showed that the transplantation of embryonic spinal cord cells could restore connections to denervated muscle. The goal of this follow-up study was to determine whether changes in the transplantation environment would improve reinnervation. Dr. Thomas and her colleagues showed that transplantation of fewer embryonic spinal cord cells into the nerve after it had already degenerated for a week improved the growth of new nerve fibers and their reconnection to the muscle. As we look to future application in humans, for practical reasons, it is likely that any therapeutic replacement of motor cells will be delayed. It is encouraging to note from the results of this study that some muscle atrophy can still be prevented even when cell replacement is deferred.