Spinal regeneration :Canadian researchers have been able to rebuild nerves in rats by injecting the spinal cord with cells from the intestine
Tom Arnold
National Post
A Canadian laboratory has discovered that nerves can regenerate in the spine when cells from the intestine are transplanted into a severed spinal cord.
The McMaster University finding is being touted as a major breakthrough in spinal-cord injury research, potentially bringing new hope to 40,000 paraplegics and quadriplegics across the country.
"It is very dramatic," lead researcher Michel Rathbone, a professor of medicine at the university in Hamilton, Ont., said of the findings. "The important advance is that we've shown that nerves that normally do not regenerate at all can be made to regenerate with the body's own cells.
"Obviously, this has the potential to be a cure, but just as it took 60 years from the first airplane flight to get to a 747 airliner, it is a giant leap." Rathbone will present the results at a Society for Neuroscience meeting in San Diego, Calif., in November.
With spinal injuries, it is commonly thought the nerve cells are destroyed. They are not. It is the cell processes, or the long, telephone-like wires that run throughout the spinal cord, that are damaged, prompting the permanent injury. This research has the potential to reverse the damage.
In experiments with rats, the scientists extracted enteric glia cells from the intestine, purified them, and then injected the cells into the spinal cord, where sensory nerves enter. Soon, the enteric glia began migrating, prompting the nerve fibres to follow suit, returning to normal growth.
"This means we can now make nerve fibres regenerate through the spinal cord, which normally they would not do," said Rathbone. "Every single one with enteric glia showed a very robust growth of cells into the spinal cord. This is not just a little bit significant because this doesn't happen normally. It just does not happen."
Rathbone pointed out there are many advantages to working with enteric glia cells, which do everything from controlling interconnections between nerve cells to covering axons, the part of the nerve cell that delivers impulses from cells to muscles. The advantages include little likelihood of rejection by the body because the transplanted cells are from the same person.
About 50 rats were used for the research. The 40 animals that were control groups showed no response, while all 12 rats injected with enteric glia demonstrated the regeneration.
For humans, the scientific possibilities are immense. If the technique were able to regenerate the spinal cord just two or three centimetres, said Rathbone, arm and hand movements would return. "That would turn a quadriplegic into a paraplegic and totally change their quality of life.
"A person who is quadriplegic may not be able to feed themselves but if you could give them back movement of the hands, they can do many, many things," he said.
The Canadian Spinal Research Organization, a group of paraplegics and quadriplegics whose goal is to find a cure for spinal injuries, has given more than $1-million to Rathbone's laboratory in the past eight years.
"I think these findings are significant," said Ray Wickson, the group's president. "It's proving in the animal model to be successful and I can see, not tomorrow but in a few years if everything progresses the way it is going, it being used in human clinical trials."
Wickson first heard about enteric glia cell research in the late 1980s. Convinced it might one day pave the way to a cure, Wickson approached Rathbone to begin laboratory testing.
Among those who could be affected by Rathbone's research is U.S. actor Christopher Reeve. The actor, best known for his high-flying role of Superman, became a quadriplegic after he was paralyzed in a fall from a horse.
Reeve, who is an outspoken advocate of cutting-edge spinal research, including studying embryonic stem cells, broke his neck in the May, 1995, accident. He has the most severe spinal-cord injury the human body can endure, leaving him without use of his arms or legs, bladder or bowel control or sexual function. He can breathe on his own only for short periods of time.
"The promise of human trials is obviously down the road but it holds out exciting future potential," said Stephen Little, a spokesman for the Canadian Paraplegic Association. "They still have a lot of challenges but anything that could help reduce the impact of spinal-cord injuries, whether it's some kind of sensory gain or motor function gain, is just that, a big gain."
In the future, Rathbone intends to observe animals with spinal damage over a longer period of time to see whether they also produce the same regenerating result with the injection of enteric glia cells. He also hopes to begin work on larger animals, including dogs. If all goes as planned, he believes human trials will be underway within three years. |
