"We have a clear 'proof of principle' that it is possible to deliver new genes body-wide to all the striated muscles of an adult animal. Finding a delivery method for the whole body has been a major obstacle limiting the development of gene therapy for the muscular dystrophies. Our new work identifies for the first time a method where a new dystrophin gene can be delivered, using a safe and simple method, to all of the affected muscles of a mouse with muscular dystrophy," said Dr. Jeffrey S. Chamberlain, professor of neurology and director of the Muscular Dystrophy Cooperative Research Center at the University of Washington School of Medicine in Seattle. He also has joint appointments in the departments of medicine and biochemistry.
Chamberlain is the senior author of the paper describing the results, which will be published in the August edition of Nature Medicine. The paper describes a type of viral vector, a specific type of an adeno-associated virus (AAV), which is able to 'home-in' on muscle cells and does not trigger an immune system response. The delivery system also includes use of a growth factor, VEGF, that appears to increase penetration into muscles of the gene therapy agent. Chamberlain said the formula was the result of about a year of trying different methods.
Duchenne muscular dystrophy is an X-linked genetic disorder that strikes one of every 3,500 newborn boys. The genetic disorder eliminates production of the dystrophin protein, which is necessary for the structural support of muscle. Without this protein, muscles weaken to the point where the victim cannot survive.