Researchers have isolated special muscle-generating stem cells that can improve muscle regeneration and deliver the missing protein dystrophin to damaged muscles in a mouse muscular dystrophy (MD) model.

The research, carried out by Johnny Huard and his colleagues at Children's Hospital of Pittsburgh and the University of Bonn in Germany, involves the isolation of a subpopulation of muscle stem cells with special characteristics: 1) they grow and reproduce over many generations; 2) they maintain their essential character through multiple generations; 3) they can differentiate into other kinds of cells needed to regenerate muscle tissue; and 4) they resist rejection by a foreign immune system. When these cells were transplanted into the "mdx" mouse, an animal model of muscular dystrophy, numerous dystrophin muscle fibers developed, suggesting that transplanting these cells into dystrophic muscle could potentially help restore function for a time.

The study was supported in part by the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS). The Muscular Dystrophy Association, the Parent Project Muscular Dystrophy Research and the Children's Hospital of Pittsburgh also helped fund the research project.

The results may also signal that some of the major obstacles to muscle cell transplantation -- low cell survival rate, poor spreading of cells, and cell rejection by the immune system -- are being overcome. This, say the scientists, could make treatments for MD and other muscle-related diseases more effective.

Muscular dystrophy refers to a group of genetic diseases characterized by progressive weakness and degeneration of the skeletal or voluntary muscles which control movement. The muscles of the heart and some other involuntary muscles are also affected in some forms of MD, and a few forms involve other organs, as well. There are currently no specific treatments for any of the forms of MD.