265. Enhanced Plasmid-Mediated Dystrophin Expression in the mdx Mouse Model for Duchenne Muscular Dystrophy by a PhiC31 Integrase Plasmid System

Duchenne muscular dystrophy is caused by lack of dystrophin expression in skeletal muscles and is characterized by progressive degeneration of muscle fibers. To be effective, gene therapy approaches to DMD need to target a large number of fibers in the muscle, and the distribution of dystrophin through the fiber length needs to be sufficient to prevent fiber degeneration. Plasmid-based gene therapies have been shown to be a valid approach to the treatment of a variety of disorders including DMD. Concerns, however, have been raised about the ability of extrachromosomal vectors to sustain gene expression for prolonged periods of time at levels that are therapeutic.