901-90 In Vivo Genetic Engineering of Cardiac Cells: Intracoronary Administration of Antisense (AS) Oligonucleotides (ODN)

We have previously documented that transfection of antisense ODN by a highly efficient Sendai virus (HVJ)-liposome delivery system can be utilized to modify lesion formation within the peripheral vasculature in vivo. In this study, we defined the feasibility of modifying cardiac cell gene expression via a catheter-based coronary infusion of AS ODN in rabbits. The coronary artery was cannulated via an over-the-wire approach from the carotid artery. Fluorescein (F)-Iabeled ODN were utilized to evaluate the cellular distribution and kinetics of ODN uptake within the myocardium after a single intraluminal bolus of HVJ-liposomes containing ODN. Cellular uptake of F-ODN was primarily localized in the microvasculature and significant staining was also observed in conduit vessels and cardiac myocytes. Immunohistochemical analysis verified prominent localization of F-ODN within the microvascular endothelium. Expression of F-ODN was observed within 10 minutes, peaked at 1 day, and remained evident for up to one week after transfection by the HVJ-liposome method. In contrast, F-ODN infused within liposomes without the viral particle exhibited transient expression that was undetectable within 3 days. These findings indicate that a single intracoronary bolus infusion of ODN within HVJ-liposomes is a reproducible methodology for delivery of AS ODN to targeted cells within the myocardium. Future studies will characterize the feasibility of using this approach to modify cardiac structure and function via regulating myocardial cell gene expression