Injections of a new drug may partially relieve paralysing spinal cord injuries, based on indications from a study in rats, researchers have found.
“We’re very excited at the possibility that millions of people could, one day, regain movements lost during spinal cord injuries,” said Jerry Silver, professor of neurosciences, Case Western Reserve University School of Medicine, Cleveland, and a senior investigator of the study published in Nature.
Countless thousands are left paralysed by spinal cord injuries that crush and sever the long axons of spinal cord nerve cells, blocking communication between the brain and the body and resulting in paralysis below the injury.
On a hunch, Bradley Lang, Ph D, the lead author of the study and a graduate student in Dr Silver’s lab, came up with the idea of designing a drug that would help axons regenerate without having to touch the healing spinal cord, as current treatments may require. “Originally this was just a side project we brainstormed in the lab,” said Lang.
After spinal cord injury, axons try to cross the injury site and reconnect with other cells but are stymied by scarring that forms after the injury. Previous studies suggested their movements are blocked when the protein tyrosine phosphatase sigma (PTP sigma), an enzyme found in axons, interacts with chondroitin sulphate proteoglycans, a class of sugary proteins that fill the scars.
Lang and his colleagues designed a drug called ISP to block the enzyme and facilitate the drug’s entry into the brain and spinal cord. Injections of the drug under the skin of paralysed rats near the injury site partially restored axon growth and improved movements and bladder functions.
“There are currently no drug therapies available that improve the very limited natural recovery from spinal cord injuries that patients experience,” said Lyn Jakeman, a programme director at the National Institute of Health’s Neurological Disorders and Stroke division. “This is a great step towards identifying a novel agent for helping people recover.”