COLUMBIA, Mo. – A significant number of people in the United States unfortunately suffer from spinal muscular atrophy (SMA), a disease that causes progressive degeneration in the nerve cells that control muscles, causing muscle weakness and eventual death. Most often, the ones affected by this disease are children.
According to a release, researchers at the University of Missouri are studying a subtype of SMA, known as spinal muscular atrophy with respiratory distress (SMARD1), and have developed a gene replacement therapy that can be used as a treatment and controlling method for the disease.
SMARD1 is a rare genetic disease that occurs primarily between the ages of six weeks and six months and has a high mortality rate. The disease targets the spinal cord and leads to atrophy of body muscles and paralysis of the diaphragm, which controls a person’s breathing.
Children afflicted with SMARD1 become paralyzed and require continuous artificial ventilation as the condition progresses. The average life expectancy of a child with a SMARD1 diagnosis is 13 months. There is currently no cure or effective treatment for it.
Click here to listen to KMZU’s Shelby Flynn talk with Chris Lorson:
“Monogenic diseases like SMARD1, a disease that is caused by one gene, are ideal for gene therapy since the goal of the therapy is to replace the missing or defective gene,” said Chris Lorson, an investigator in the Bond Life Sciences Center and a professor of veterinary pathobiology. “Our goals for this study were to develop a vector that would improve the outcomes of the disease and for the vector to be effective in a single dose.”
Along with Monir Shababi, associate research professor in the Department of Veterinary Pathobiology in the MU College of Veterinary Medicine, Lorson developed a gene replacement therapy that was dispensed to infantile mice diagnosed with SMARD1. The therapy is able to cross the blood-brain barrier and directly target motor neurons affected by SMARD1.
“One of the remarkable aspects of this type of gene replacement is that it will last for an extended period of time,” said Lorson. “The ability of the therapy to cross the blood-brain barrier, a protective barrier that typically prevents toxins or microbes from entering the brain, opens the door for IV administration, allowing us to target motor neurons with a relatively non-invasive procedure.”
The study found that a low dose of the gene replacement therapy caused significant improvements in muscle strength, protein expression in motor neurons and a longer life span of the SMARD1 mouse model.
“I think it’s exciting to demonstrate in other disease contexts that you’re able to really restore quite a bit of function,” Lorson said. “Now, it’s not perfect, but I think what we’ve been able to show is that if you get this disease gene back into this model early enough, there is quite a bit of therapeutic benefit.”
With the findings from this study, Lorson and his team are working to create a most suitable delivery system for the gene replacement therapy, as in determining the exact dose of the vector needed, when in the disease cycle the therapy will be most effective, and where to administer in the body for the best results.
“What we’ve seen here is that there really has been a renaissance in the last couple of years, and I think that this is just the beginning of a new wave of molecular medicines that are on the cusp of really changing how we develop medicines and how we can develop precision medicines specifically for patients,” Lorson said. “And I hope this really ushers in a new wave of therapeutics that really begin to beat back some of these devastating diseases that we see in the clinic.”