749. Effective Plasmid DNA Dose Range and Promoters for Gene Expression in Muscle Following Hydrodynamic Limb Vein Delivery of pDNA into Rodents and Primates

Plasmid DNA (pDNA) is efficiently delivered to limb muscles of rodents and large animals by hydrodynamic limb vein (HLV) injection, a facile procedure that uses a tourniquet or blood pressure cuff placed distal to the injected vein to delimit the target tissue. In rhesus monkeys of various weights and ages we detected much higher reporter gene expression when the pDNA dose was above an apparent threshold level measured in pDNA dose/gram muscle of the target tissue. Studies in mice and rats were carried out to investigate these dose response effects and confirmed a threshold dose above which expression correlated directly with the dose and below which it did not. The percentages of transfected myofibers were also shown to increase as the pDNA dose increased. Co-localization of transgene expression and fiber type by immunohistochemistry showed that all types of myofibers were transfected at similar efficiencies, both in a primate and in the mdx dystrophic mouse model.