Actor Christopher Reeves's tragic spinal cord injury and his subsequentefforts to raise money for neurological research have focused attention on the perils of nervous-system damage. Paralysis occurs because injured neurons in the spinal cord are unable to rebuild their long, tentacle-like axons, along which nerve impulses travel. But recent experiments by Michal Schwartz, Ph.D., a neuroimmunologist at Israel's Weizmann Institute of Science, help explain why it's so difficult to recover from spinal cord injuries--and may lead to a promising treatment.
When injury occurs in other parts of the body, vigilant immune-system cells called macrophages carry away cellular debris and churn out substances essential for building new cells. But cells in the spinal cord release chemicals that keep macrophages away, hindering repair, Schwartz has discovered this problem can be overcome by transplanting macrophages that have first been activated, or turned on, in the lab. The technique has already been used to repair damaged nerves in rats; one day it may help heal many brain and spinal cord injuries in people.
