Since 2009, there has been much research and big developments in the area of degenerative myelopathy (DM). The research has been progressive in nature, and made possible largely due to the similarity between DM and amyotrophic lateral sclerosis (ALS) in humans. ALS is diagnosed in approximately 6 000 people in the U.S. on an annual basis, affecting two in every 100 000 people. People diagnosed with ALS will generally live for three to five years before respiratory failure leads to loss of life.
ALS occurs in Multiple Forms
There is still much that remains unknown about ALS. About 90% of ALS cases are sporadic, with the disease occurring at random with no clear associated risk factors or family history of the disease. Approximately 5-10% of ALS is genetic, and links have been found to more than a dozen gene mutation expressions. Approximately 20% of these are due to the SOD1 gene mutation that we see in dogs with DM. Dogs with DM therefore have a naturally occurring animal model of ALS, making them good candidates for further research into the treatment and cure of this disease (Coates et al., 2009).
How is ALS Diagnosed?
Like DM, ALS can be difficult to diagnose in the early stages as it mimics other neurological conditions. Rule-out tests include an electromyogram, nerve conduction tests, magnetic resonance imaging, blood and urine tests, a spinal tap and muscle biopsy.
Biomarkers are being researched to diagnose and assess the progression of the degeneration of neural cells. At this point the presence of phosphorylated neurofilament heavy proteins (pNF-H) within the blood or spinal cord is a known biomarker of ALS. pNF-H has been found to be present in the spinal fluid of canines with DM, and a test is being further developed to make it available within the veterinary community as a diagnostic measure (Coates et al., 2017).
How is ALS Treated?
Much like in our canine patients, treatment for ALS is supportive and aims at maintaining mobility and quality of life. It is carried out by a multi-disciplinary team. The condition is degenerative and there is no cure. Riluzole can be used and is believed to reduce damage to the motor neurons, and Edaravone is used to slow the decline of daily functionality. Physical therapy is used to enhance independence and safety throughout the course of the disease. Speech therapy can assist people through the process of losing their ability to vocalize and can help them develop alternative methods of communication. Nutritional support is essential in maintaining the health and wellbeing of the patient, and breathing support becomes important towards the end of the disease.
There are multiple organizations dedicated to finding a cure for DM, and many more that are dedicated to finding a cure for ALS. As the organizations and research facilities start to work together, results are looking hopeful for both species.
Recent studies have focused on gene-silencing targeted at the SOD1 and DLA-DRB1 genes, stem cell treatment and drug therapies.
What does Tomorrow Hold?
For those living with ALS, and for our canine DM patients today, there may not be much that we can offer at present. But with the promising research being conducted in canines with the purpose of treating and curing this disease in humans, we can certainly hope and expect some treatment breakthroughs in the future.