Short legged dogs with long torsos are congenitally prone to spinal disc ruptures, often leading to paralysis. These intervertebral disc traumas are usually a combination of compressive and concussive forces that impinge upon the fragile tissues of the spinal cord, usually in the lumbar area. There may be ways to prevent paralysis if the rupture is detected (dogs might show pain of hind leg ataxia – the ‘drunken sailor’ walk). Treatment can include rest and confinement, or major surgery. But you’ve seen images of Dachshunds, Lhasa apsos, Pekinese or beagles with wheels at the hind legs.

Now, researchers at the University of California, San Francisco (UCSF) and Texas A&M College of Veterinary Medicine & Biomedical Sciences hope they can help the pets. The vet service sees 120 dogs a year with sudden onset hind limb paralysis. And using the dogs as a model, the UCSF group aims to help people with similarly injured spinal cords.

Here’s a UCSF press release.

With a three-year, $750,000 grant from the U.S. Department of Defense, Linda J. Noble-Haeusslein, Ph.D. will expand her research with an experimental drug called GM6001. This is a general inhibitor of a protein called matrix metalloproteinase-9, MMP for short, which is elevated after spinal cord trauma. MMP appears to degrade nerve pathways, thus boosting local inflammation. The GM6001 treatment can’t undo damage or repair cells in the cord but it might calm the chaotic cascade of secondary swelling and bleeding that lead to further cell destruction in the hours and days after injury.

GM6001 has already proven effective in a small animal model at UCSF. Noble-Haeusslein has published on the topic; she and her UCSF colleague Zena Werb, Ph.D., showed how the drug blocks the action of MMP found in the spinal cord of mice; this helps them recover if they are treated within three hours of the injury and treatment continues for three days.

“The mice show a remarkable recovery,’’ said Noble-Haeusslein. “They go from dragging hind limbs to actually taking functional steps. We can see the benefit as early as one day after the injury.’’

Does the drug work if given more than three hours after the injury? They don’t know yet but are working on it. They don’t know if will work on the larger mammal, either.

Over 30 month course of the study, the researchers hope to enroll 80 paralyzed dogs in a randomized clinical trial; all dogs will receive surgical treatment and rehabilitation. Some dogs will be given the experimental drug, others will receive a placebo.

The study will also examine the effect of the drug if given 6 to 12 hours after the initial injury.

“It would be phenomenal if it works,” said Noble-Haeusslein, “We are in a unique position of being able to treat a dog population where there are simply no current therapies that could effectively improve their hind limb function.”

Noble’s co-investigator on the new study, Jonathan Levine, DVM, an assistant professor in neurology at Texas A&M University, will treat the dogs through injections of GM6001. He will then put the dogs through rehabilitation and assess their recovery. 

Ongoing studies at UCSF hope to refine delivery of the drug and thus optimize recovery.

If they work out, the trials in dogs may lead to the development of similar treatments for people with spinal cord injuries, Noble-Haeusslein said.

Go here for more on this kind of canine paralysis.