LONDON, April 10 (Reuters) - In what could be the first ray of hope for patients with spinal cord injuries, British scientists have used an enzyme treatment to repair severed nerves in rats.
The enzyme, called chondroitinase ABC, cuts like a machete through the thicket of cells and molecules that forms like brambles at the site of the spinal injury. It allows damaged nerve endings, or axons, to regenerate. If the treatment, reported in the science journal Nature on Wednesday, is tested and proven effective in humans it could be combinated with other methods in future to help paralysed patients like "Superman" actor Christopher Reeve.
"It is quite an important finding because it shows this relatively simple treatment with an enzyme can promote regeneration of axons and also some recovery of function," Elizabeth Bradbury, a neurologist at King's College London, said.
But she added it was not a miracle cure and many obstacles must be overcome before spinal cord could be repaired in humans.
LACK OF REGENERATION
After a spinal cord injury, which usually results from car or sporting accidents, in Reeve's case a fall from a horse, sensation and movement are lost because the nerve fibres do not regrow and cannot communicate with other nerve cells.
Bradbury and her team infused the rats with the enzyme for 10 days after they were injured and monitored their progress. "We've applied it to injured animals and found they can get recovery of some of their neurological functions after a spinal cord injury," she said in a telephone interview.
The rats had been disabled but not paralysed. Bradbury said the results were promising because the treatment helped them walk better and more normally. There was also nerve regeneration in the sensory and motor nerves of the spinal cord.
"If we can target this as well as some other factors there might be hope for getting some recovery of function for spinal injury patients," Bradbury said.
She added it would probably be one of several treatments researchers are hoping eventually to use on spinal cord injury patients to help them regain sensation and movement.
The rats suffered injuries to an area of the spinal cord that would equate to serious damage in humans, but Bradbury said Reeve's injury was higher up on the spinal cord and resulted in more severe disability.
The rats were also given the enzyme immediately after the injury so the researchers were unsure of the impact it would have on long-term spinal injury patients such as Reeve.
The next phase of their research will be to delay treatment after the injury and to test it on animals with damage to different areas of the spine.
John Cavanagh of the International Spinal Research Trust (ISRT) said the enzyme could be one of the first treatments for spinal injury patients. "It offers hope to people with spinal injuries," he said.
But the head of research at ISRT, which funds studies into spinal injuries, added the next challenge would be to scale it up to humans whose injuries are huge compared to those in rats.