In vivo human MCP-1 transfection in porcine arteries by intravascular electroporation.

PURPOSE: The purpose of this study was to develop a nonviral gene transfer method for therapeutic delivery of the human monocyte chemoattractant protein-1 (MCP-1) in patients with peripheral artery disease, using local catheter-mediated electrotransfer of naked plasmid DNA into arteries.
METHODS: Arterial walls of the A. profunda femoris of pigs were transfected either with a human MCP-1 or with a firefly luciferase-encoding DNA construct. The efficacy of electrotransfer of DNA was analyzed after 2 days by quantitative polymerase chain reaction (PCR) or luciferase activity measurements. To optimize MCP-1 gene transfer conditions, a voltage range of 60-150 V was applied as a train of six square pulses of 20 ms each at 1 Hz and was combined with a dose of 150 microg DNA. Subsequently, the optimized voltage was used to test a dose range of 80-300 microg DNA.
RESULTS: The voltage optimum for arterial transfection was observed at 80 volts. Using this setting, the dose application of 300 microg MCP-1 plasmid DNA (the maximal dose tested) demonstrated the highest MCP-1 expression signal. The electric pulses and the transfer and expression of human MCP-1 per se did not induce endogenous porcine MCP-1 expression in treated arteries. Interestingly, angioplastic predilation of the artery before gene transfer, which had originally been postulated to enhance transfection by improving access of the plasmid to subendothelial cell layers, resulted in an attenuated transfection efficacy.
CONCLUSIONS: The present study demonstrates that transluminal catheter-based electroporation provides an efficient technology for nonviral intravascular gene transfer by just applying unformulated DNA.