Injecting stem cells into the spinal cord of parlayzed rats has helped the animals to regain some of the movement in their back legs. Dr Douglas Kerr and colleagues at Johns Hopkins University School of Medicine were expecting the stem cells to aid the rats’ recovery by developing into new nerve cells that would repair the damaged nerve circuitry. However, results showed that the injected cells actually worked by bathing the damaged nerve cells in nourishing compounds and thus helping them survive. When nerve cells die, they send out signals that usually cause neighboring cells that are healthy to die as well. This cascade is responsible for much of the brain damage caused by stroke or severe head injury. However, the injected stem cells seemed to protect healthy cells from the cascade by producing two proteins called transforming growth factor-alpha (TGF-alpha), which helps nerve cells survive, and brain derived neurotrophic factor, which strengthens their connections to other nerve cells. Kerr warned that the treated rats were “far from normal” but their improvement was clinically significant.
SOURCE/REFERENCE: J Neurosci. 2003 23: 5131-5140.
