New Protein Promising in Nerve, Brain Injury Study

New studies showing that a protein appears to be linked to the regrowth of damaged nerves in mammals may help scientists better understand injury-caused paralysis, Stanford University scientists report.

“The new findings can help us begin to understand at the molecular level why mammalian nerves in the brain and spinal cord cannot regrow after injury,” said Dr. Eric Shooter, professor and chairman in the department of neurobiology at Stanford University School of Medicine.

The protein was initially discovered by Shooter and Dr. Pate Skene, assistant professor of neurobiology. New studies show it to be present in newborn rats and in rats with damaged nerves.

Nerve Growth Role

“The protein may play a role in nerve growth in the young animals and in nerve repair in the injured adult rats,” Shooter said.

“Although this is only a basic scientific discovery with no medical applications now, the finding is a small step in the effort toward developing a treatment for spinal cord injuries and other currently irreversible conditions caused by damage to brain and spinal cord nerves.”

The scientists reported the results of the research, funded in part by the National Institutes of Health, in the journal Science.

In mammals, injuries to the peripheral nerves, such as those in the limbs or skin, can be repaired because axons--the long fibers of nerve cells--are capable of growing back to reform the pathways originally established during development, Shooter said.

Brain Tissue Different

“But for some reason, damaged nerves of the brain and spinal cord do not regrow,” he said. “This is why spinal cord injuries, head traumas and other conditions involving injury to the brain or spinal cord are so severe and irreversible.”

The scientists found in rats that a specific protein associated with growing nerves is synthesized at a high rate early in development when nerves are first being formed. Later in life, when the nervous system is established, the protein’s synthesis drops off to a much lower rate.

“But if the nerves are damaged, then adult rats synthesize the protein at high rates again both in the peripheral nerves and in the central nervous system,” Shooter said.

Accumulates in Nerves

“The protein accumulates in the peripheral nerves, which regrow to repair the damage, and once these axons have regrown, the protein’s synthesis falls to low levels again.”