This re-engineered virus was then injected into the muscles of the mice. The promoter they chose, the myosin light chain promoter, is specific to muscle tissue so that IGF-1 production would be limited to the muscle. The researchers did not want any IGF-1 that may have accidentally leaked outside of the muscle to proliferate and stimulate growth of other organs. They've shown they can do both. While the method of delivery is similar to other forms of gene therapy, the aim is somewhat different.
Much gene therapy is aimed at repairing a defective protein or fighting an invading organism.
But it's turned out to have somewhat different applications. Without satellite cells, IGF-1 is not effective. Experiments with a Duchenne's mouse model are bearing that out, he said. Sweeney has higher hopes for Becker's muscular dystrophy, in which the rate of damage is slower. If we build greater muscle mass and boost the satellite cells, we may be able to stabilize the condition.