Update on Optic Nerve Regeneration
Dr. Larry Benowitz and colleagues at Children's Hospital Boston and Harvard Medical School have made a discovery that could someday prove useful in reversing optic-nerve damage caused by glaucoma.
Benowitz and colleagues have discovered a naturally occurring growth factor called oncomodulin that stimulates regeneration of injured nerve fibers, known as axons, in the central nervous system. Axons conduct impulses away from the body of the nerve cell, forming connections with other nerve cells or with muscles. Under normal conditions, most axons in the mature central nervous system — which consists of the brain, spinal cord and eye — cannot regrow after injury.
Dr. Benowitz believes oncomodulin could someday prove useful in reversing optic-nerve damage caused by glaucoma. “We’re in the midst of an exciting era of research in nerve regeneration," Benowitz says. “There are a lot of promising leads in the area of blocking molecules that inhibit regeneration. But to get really strong regeneration, you also have to activate nerve cells’ intrinsic growth state.”
Axon growth nearly doubled when oncomodulin was added to retinal nerve cells in a Petri dish with known growth-promoting factors already present. No other growth factor was as potent. Benowitz and colleagues also discovered that oncomodulin switches on a variety of genes associated with axon growth.
This current study builds on research funded in part by the Glaucoma Research Foundation from 1999-2001. In that study, Dr. Benowitz studied the optic nerve and found that an injury to the eye activated axon growth: it caused an inflammatory reaction that stimulated immune cells known as macrophages to move into the eye. Macrophages that enter the eye produce oncomodulin, which acts upon retinal nerve cells to stimulate axon regeneration.
The Benowitz lab is currently working on ways to combine oncomodulin with other agents to enhance the amount of axon regeneration obtained.
Larry Benowitz, PhD is Associate Professor of Neurosurgery at Harvard Medical School/Children's Hospital, Department of Neurosurgery.
Last reviewed on November 12, 2010