Injections of a man-made liquid may some day help treat spinal cord injuries and prevent permanent paralysis, according to an animal study.
One day, ambulances could carry the chemical for use at accident scenes, sparing people from spinal damage.
That’s the dream of Richard Borgens, PhD, who directs the Center for Paralysis Research at Purdue University’s veterinary medicine school. He knows his vision is a long way off, but it’s one step closer to reality thanks to his latest experiment.
The study was conducted at Purdue University, Texas A&M University, and Indiana University-Purdue University in Indianapolis. It appears in the Journal of Neurotrauma’s December edition.
Borgens and colleagues recently studied Paraplegic dogs with naturally occurring spinal damage. “Certain dog breeds can easily injure their backs simply by jumping off a couch,” he says in a news release.
In the study, the dogs were required to have been paraplegic for 72 hours or less. All the animals received spinal-cord imaging and were examined and videotaped to document the nerve damage resulting from the spinal cord injury. The researchers assessed pain sensation and motion of the animal’s legs as well as reflexes.
Consenting dog owners allowed their pets to get one of two different shots. One contained polyethylene glycol, or PEG, a chemical that’s safely used in other medicines. The other shot used another polymer called Poloxamer 188 (P-188).
Nineteen dogs received injections of PEG and 16 got P-188. The shots were given within 72 hours of admission. Afterward, researchers monitored the dogs’ progress for six to eight weeks.
The injections roused many dogs out of their paralysis. “Nearly 75% of the dogs we treated with PEG were able to resume a normal life,” he says.
“Some healed so well that they could go on as though nothing had happened. … More than half of the dogs were standing or walking within two weeks of treatment.”
The gains came quickly. “In most dogs, we found a PEG injection within 36 hours can restore sensitivity and even mobility within three weeks,” says Borgens in the release. “In most cases, you could usually notice positive signs within 3-5 days.”
Of the two polymers, PEG had better results, although P-188 also helped. Compared with records of similarly injured dogs that didn’t get polymer shots, the test groups healed better and had better outcomes.
How do the polymers work? The details aren’t precisely clear, but here’s the rough idea.
When spinal cord injuries occur, cells are damaged and may even be torn open. In that vulnerable state, the cells lose at least some of their ability to pass along nerve impulses. Before the wounded cells die, they transmit a chemical “suicide signal” to neighboring cells, sparking a deadly chain reaction, says Borgens in the news release.
Polymers save the day by acting as a sort of cellular bandage. They patch over the torn membranes, short-circuiting the cells’ downward spiral. That can leave Nerve Impulse transmission intact.
Borgens calls the results “unprecedented” but cautions that polymers are nowhere near ready for human use. Dogs and humans have different spinal cords, and further testing is needed.
Unfortunately, polymers probably wouldn’t fix existing cases of paralysis. But eventually, they might eventually help other people avoid that fate.
SOURCES: Laverty, P. Journal of Neurotrauma, December 2004; vol 21: pp 1767-1777. News release, Purdue University.
By Miranda Hitti
WebMD Medical News
