Amyotrophic Lateral Sclerosis (ALS) continues to affect and consume the lives of thousands of people around the world. A new and different therapy that suppresses specific gene expressions is currently being tested as treatment for dogs with Degenerative Myelopathy. Degenerative Myelopathy is a spontaneously occurring adult-onset disorder of the nerves within the dog’s spinal cord.
Dominik Faissler, the lead veterinary neurologist at Tufts University is recorded as saying that adding to the life of the pets by approximately two years will be regarded as a great success. He further added that they would be doing something phenomenal for the pets while at the same time contributing to human medicine.
Over time, canine degenerative myelopathy causes progressive paralysis in dogs. The most affected breeds are German Shepherds, Bernese mountain dogs, boxers, Rhodesian Ridgebacks and Chesapeake Retrievers. Dogs with this disease begin with loss of coordination of the hind legs and eventually die from breathing failure.
In a press release, a neurologist and leader in ALS research Robert H. Brown Jr., said “In dogs, it turns out there’s a mutation in the SOD1 gene, which normally makes an antioxidant protein that helps protect nerve cells from a variety of cellular stresses and injuries.” He further added that when the SOD1 gene gets mutated, it becomes toxic to the nerves, killing off motor neurons or nerve cells in the dogs in a similar way that the same genetic mutation does in some patients of ALS.
The drug that is currently being tested and studied consists of a single injection of an engineered adenovirus into the spinal fluid. It is designed to transmit deoxyribonucleic acid (DNA) particles across the blood-brain barrier and into the central nervous system (CNS). The DNA particles then “silence” mutated genes which are believed to cause the progressive paralysis observed in dogs suffering from degenerative myelopathy. The modified adenovirus is from a family of viruses that is commonly associated with common cold in humans. The virus in its natural design is able to cross into the CNS. This trait is being exploited by researchers as an agent to deliver the therapy to the defective genes associated with canine degenerative myelopathy.
The study that commenced in December 2016 currently has four dogs enrolled. They are assessed every twelve weeks at which point they undergo testing of their motor and neurological function. The treatment has so far been observed to be safe from initial results of the pilot study. The effectiveness of it in reversing disease cannot be accurately determined yet, however, mice that were genetically modified to have a condition similar to ALS have exhibited encouraging results and responded to the treatment.
A successful study in dogs could eventually lead to clinical trials in humans, says Brown. Studies are ongoing for a similar therapy for SOD1 ALS related and for a mutation found in Huntington’s disease. Such treatments could be employed in future for neurodegenerative and neuromuscular diseases occurring in humans.