Scientists have identified a gene that prevents the brain and spinal cord from rewiring themselves after an injury, a step toward new treatments for thousands of people paralyzed like Superman star Christopher Reeve.
Researchers from Europe and the U.S., writing in Nature magazine have identified a gene that blocks injured cells in the brain from regrowing the connections that allow nerve impulses to travel through the body, reports CBS News Correspondent Richard Roth.
Dubbed "Nogo," the gene produces a protein that prevents nerve-cell connections in the central nervous system from regenerating after they are cut. Experiments in rats showed that when the protein is blocked, the spinal cord can repair itself.
Neurologists hailed the work as a landmark step. But they cautioned that other factors may also inhibit nerve regrowth.
"It is important not to give patients false hope," said Dr. Ben Barres, a professor of neurology at Stanford University. "But I think there are a lot of grounds for optimism now."
If the scientists are right, they have solved an old mystery: Why can't connections in the central nervous system - the brain and spinal cord - repair themselves, when connections in the peripheral nervous system - everything else - can?
The answer is that the Nogo protein is present in the central nervous system but not in the other nerves. Nogo may exist to hardwire the brain and spinal cord - or fix them in place - after they have developed, and prevent them from going wild.
A team led by Martin Schwab of the Brain Research Institute at the University of Zurich in Switzerland has been working on Nogo for 15 years, and created an antibody that blocks the Nogo-created protein.
In test-tube experiments, nerves dissected from rats were exposed to the antibody. The nerves regrew several hundred nerve connections known as axons, or the tiny branches that transmit impulses from one nerve cell to the next.
In an additional set of experiments that were not published in Nature, Schwab's team said it partially cut the spinal cords of rats, paralyzing the animals, then gave the rodents the antibody for two weeks. The nerves regrew, and the animals resumed normal activities, grabbing food pellets and climbing a rope.
"The expectation over a period of time would be that people might be able to gain either partial - or optimistically full - function of the damaged spinal cord in the case of spinal injuries," said Dr. Frank Walsh, one of the researchers.
Christopher Reeve's foundation helped fund some of the U.S. research, at Yale, and the actor believes it's one of a series of advances that will someday allow him to walk again. Many scientists, though, are more cautious. They're calling this a landmark step, but one on what is still a very long road.
Reeve said he hopes to take part in human tests in about five years, once ork has progressed to the point he would feel safe.
"It will be a question of money and time," Reeve said from his office in Bedford, N.Y. "But the field now is very alive and there is suddenly a lot of progress being made."