A chemical compound could help restore function to patients who have suffered a spinal cord injury.
The promising new compound, dubbed Intracellular sigma peptide (ISP), allowed paralyzed muscles to activate in more than 80 percent of the animals on which it was was tested, Case Western Reserve University reported. In the recent study 21 of 26 animals with spinal cord injuries regained the ability to move, urinate or both.
"This recovery is unprecedented," said Jerry Silver, a Case Western Reserve University School of Medicine professor of neurosciences. "Each of the 21 animals got something back in terms of function. For any spinal cord-injured patient today, it would be considered extraordinary to regain even one of these functions, especially bladder function. ISP additionally has treatment potential for diseases where the body produces destructive scarring such as heart attack, peripheral nerve injury and multiple sclerosis (MS)."
Following a spinal cord injury molecules called proteoglycans collect in scar tissue at the injury site and in the perineuronal net (PNN). These molecules help maintain the structure of the immune system in healthy individuals, however in the event of an injury they can create "impenetrable nets" that prevent the regeneration of new nerve connections. These connections are responsible for transmitting information through electric impulses that allow humans or animals to control their movements and bodily 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 program director at the NIH's National Institute of Neurological Disorders and Stroke in Bethesda, Md. "This is a great step toward identifying a novel agent for helping people recover."
ISP has the ability to penetrate cell membranes, including those that are encased in scar tissue. It then turns off the neuron's proteoglycan receptor on/off switch.
The method was tested in 26 animals with severe spinal injuries that received injections for a period of seven weeks.
"We don't know why a particular animal regained a specific function," Silver said. "That is one of the big remaining questions."
In the future the researchers hope the therapy will be used on human patients with spinal injuries.
The findings were published Dec. 3 in the journal Nature.
