A drug called fasudil can extend the average lifespan of mice with Spinal muscular atrophy (SMA) from 30.5 days to more than 300 days, scientists from the Ottawa Hospital Research Institute (OHRI) and the University of Ottawa have revealed. The study is published today in BioMed Central's open access journal BMC Medicine, by Dr. Rashmi Kothary, his graduate student Melissa Bowerman and others.
SMA is the leading inherited cause of death in infants and toddlers, affecting approximately 25,000 people in Canada and the United States. Scientists have known for many years that this disease is caused by inherited mutations in a gene called survival motor neuron 1 (SMN1). Most early attempts at developing treatments for SMA focused on replacing this gene, however, Dr. Kothary's group has focused on understanding and targeting the physiological defects present in certain nerve cells with SMA. These cells have a weakened internal scaffold, which hinders their ability to connect with muscle cells and contributes to the severe muscle weakness associated with SMA.
Two years ago, Dr. Kothary and his team showed that a laboratory compound called Y-27632, which targets an enzyme that is involved in maintaining the cellular scaffold, could greatly increase lifespan in a certain mouse model of SMA. In this new study, they tested a compound called fasudil, which is similar to Y-27632, but has the advantage that it has already been approved for human clinical trials for other conditions, meaning that it could possibly be re-targeted to use in clinical trials for SMA more quickly than a completely new drug.