A team of researchers at Washington University School of Medicine in St. Louis have demonstrated a new approach to treating muscular dystrophy. (Read more) Mice with a form of this muscle weakening disease showed improved strength and heart function when treated with nanoparticles loaded with rapamycin, an immunosuppressive drug recently found to improve recycling of cellular waste.
The investigators, led by Dr. Sam Wickline, studied a mouse model of Duchenne muscular dystrophy, which is an inherited disease that exclusively affects boys, who become wheelchair bound by age 12 and die from heart or respiratory failure in their 20’s. The faulty gene that causes the disease prevents the body from producing dystrophin, a protein crucial for maintaining muscle cell integrity and function. The new study demonstrated that mice with muscular dystrophy, in addition to missing dystrophin, also can’t recycle cellular waste, a process known as autophagy, or self-eating. “Autophagy plays a major role in disposing of cellular debris,” said Samuel A. Wickline, MD, the James R. Hornsby Family Professor of Medicine. “If it doesn’t happen, you might say the cell chokes on its own refuse. In muscular dystrophy, defective autophagy is not necessarily a primary source of muscle weakness, but it clearly becomes a problem over time. If you solve that, you can help the situation by maintaining more normal cellular function.” The research is published in the American journal FASEB (2014:28, 2047-61).