996-11 Direct Gene Transfer and Expression with Arterial Iontophoretic Catheter Delivery

• Published in: Journal of the American College of Cardiology Vol. 25; no. 2; p. 324A
• Main Authors: Pompili, Vincent J., Srivatsa, Sanjay S., Jorgenson, Michael A., Stelter, Adele, Holmes, David R., Katusic, Zvonimir, Schwartz, Robert S.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.02.1995
• ISSN: 0735-1097; 1558-3597
• DOI: 10.1016/0735-1097(95)92803-D

Iontophoresis is a technique of molecular delivery which uses electric current to enhance movement of charged molecules into tissues. A porous balloon catheter was tested with a central silver chloride electrode capable of generating a potential gradient across the arterial wall using an adhesive patch placed on the skin to serve as the anode. We hypothesized that this catheter delivery system might effectively transfer negatively charged plasmid DNA into arterial cells in vivo. To localize plasmid DNA arterial delivery, a 7 Fr iontophoretic porous balloon catheterwast,’aced into porcine carotid arteries underflouroscopic guidance. 15μg of 35S-Iabeled plasmid DNA (1.4×106 cpm/μg) expressing the heat stable human alkaline phosphatase (hAP) gene with an RSV promoter was infused through the balloon at 6 atm pressure. A constant current density of 2.5 mA/cm2 was maintained for 10 minutes. The ;35S-labeled plasmid DNA delivery was repeated on the contralateral carotid artery under identical conditions with the absence of electric current. 20 minutes after gene transfer, the arteries were fixed in situ and processed for autoradiography. To analyze gene transfer and expression, 8 porcine carotid arterial segments were subject to iontophoretic gene delivery for 10 minutes at 6 atm with a current density of 2.5 mA/cm2 using the RSV hAP plasmid (n=6) or control plasmid (n=2). Animals were sacrificed 5 days after gene delivery and the transfected arteries analyzed by PCR and heat stable alkaline phosphatase histochemistry. Autoradiography of the arteries which underwent ;35S-labeled plasmid delivery revealed minimal radiolabel in the luminal cells of the control artery in which current was not delivered. In contrast, significant amounts of radiolabel were present in the media and adventitia of the artery subject to current delivery. PCR analysis of the arterial segments studied 5 days after delivery confirmed gene transfer in all hAP segments and was negative in control arteries. Staining for heat stable recombinant alkaline phosphatase activity demonstrated recombinant protein expression in 5% of medial cells and 10% of adventitial cells in arteries which underwent hAP gene transfer. Control arteries were negative for hAP staining. Iontophoretic catheter gone delivery can be used to perform direct plasmid DNA delivery with expression of recombinant protein in medial and adventitial cells.