They act as a sort of patch kit. Boys with DMD have plenty of myoblasts, and their damaged muscles get repaired like anyone else's. So the repair is a temporary fix at best and, ultimately, degeneration outstrips regeneration. In the late 1980s, just after the discovery of the dystrophin gene and protein, doctors and researchers reasoned that putting myoblasts with a functional dystrophin gene into boys with Duchenne might be a very good way to keep muscles healthy. Nevertheless, after studies in mice looked promising, MDA-sponsored researchers began putting myoblasts into boys with Duchenne on an experimental basis in the early 1990s.
Some studies suggest the immune system is interfering with the survival of the transplanted cells.
At this time, MDA is still studying myoblast transfer in animals. MDA doesn't make specific recommendations about treatment of DMD, preferring to leave those decisions to families and their MDA clinic doctors. However, MDA's Scientific and Medical Advisory committees do make decisions about what grants to fund and which medical treatments are likely to have promise. The Medical Advisory Committee has declined to approve grants for any further clinical trials of myoblast transfer until animal studies show that the effectiveness of the procedure can be substantially improved.