Scientists at the Washington University School of Medicine in St. Louis believe that gene therapy could one day be used as fat-reducing therapy.
In a new study conducted on mice, scientists found that gene therapy helped build significant muscle mass quickly and reduced the severity of osteoarthritis in the mice without exercising more. Surprisingly, the therapy also staved off obesity, even when the mice ate an extremely high-fat diet.
Senior investigator Farshid Guilak, Ph.D., the Mildred B. Simon, Research Professor of Orthopaedic Surgery and director of research at Shriners Hospitals for Children—St. Louis said, “Obesity is the most common risk factor for osteoarthritis. Being overweight can hinder a person’s ability to exercise and benefit fully from physical therapy. We’ve identified here a way to use gene therapy to build muscle quickly. It had a profound effect on the mice and kept their weight in check, suggesting a similar approach may be effective against arthritis, particularly in cases of morbid obesity.”
Scientists gave 8-week-old mice a single injection of a virus conveying a gene called follistatin. The gene works to obstruct the action of a protein in muscle that keeps muscle growth in check. This empowered the mice to gain significant muscle mass without exercising more than usual.
Even without additional exercise and while continuing to eat a high-fat diet, the muscle mass of these “super mice” more than doubled, and their strength nearly doubled, too. The mice also had less cartilage damage related to osteoarthritis, lower numbers of inflammatory cells and proteins in their joints, fewer metabolic problems, and healthier hearts and blood vessels than littermates that did not receive the gene therapy. The mice also were significantly less sensitive to pain.
During the study, scientists were concerned that some of the muscle growth might lead to being harmful. But, they found that heart function improved, as did cardiovascular health in general.
Although scientists think that long-term studies are required to determine the safety of this type of gene therapy, if safe, the strategy could be particularly beneficial for patients with conditions such as muscular dystrophy that make it challenging to build new muscle.
Guilak said, “More traditional methods of muscle strengthening, such as lifting weights or physical therapy, remain the first line of treatment for patients with osteoarthritis. Something like this could take years to develop. Still, we’re excited about its prospects for reducing joint damage related to osteoarthritis, as well as possibly being useful in extreme cases of obesity.”