Building on their previous research, scientists at Yale have developed a synthetic peptide that promotes nerve fiber growth in the damaged spinal cords of laboratory rats.

If applied to humans, this finding could reverse the effects of brain and spinal cord injuries resulting from trauma, stroke or degenerative diseases such as multiple sclerosis. The study, published in the May 30 issue of Nature, confirms which molecules block axon regeneration in the spinal cord, according to lead author Stephen M. Strittmatter, M.D., Ph.D., the Vincent Coates Chair of Neurology. It also shows that a peptide can spur new growth. Axons extend from neurons and carry nerve impulses to target cells.

In previous research Strittmatter discovered a protein he called Nogo, which inhibits regeneration of axons. A subsequent paper described the receptor through which Nogo acts. His latest research has found a way to counteract the action of the Nogo protein.

“We developed a way to block Nogo with a peptide that binds to the Nogo receptor and prevents it from doing its normal job,” said Strittmatter. “There is no drug used today to promote axon recovery in humans, so it is hard to predict how well this drug will work in humans.”

In laboratory rats the drug did promote the growth of nerve fibers, and the rats could walk better than those that did not receive the treatment. The peptide, comprising 40 amino acids, was inserted into each rat’s spinal canal through a catheter over four weeks. Human trials will not begin until researchers determine whether the synthetic peptide can promote nerve fiber growth for weeks or months after injury, and whether the peptide is effective and safe for use in humans.

“There is some reason to think the peptide might promote growth in older injuries, because some damaged nerve fibers in the brain and spinal cord just sit there,” Strittmatter said. “If we had some way to block these inhibitors the nerve fibers might grow back again.”