Study of gene delivery in a rabbit vein graft model. Improvement of the efficiency of gene transfer into vein grafts.

Gene therapy is a therapeutic strategy in treating cardiovascular disease. Vein graft failure, the major limitation on coronary artery bypass surgery, may be amenable to gene approaches. Some studies describe gene therapies using functioning genes to prevent vein graft stenosis. Gene transfer efficiency remains a major issue. In this rabbit vein graft model, we studied gene delivery using a replication-deficit recombinant adenovirus to improve gene transfer efficiency into vein grafts. The adenovirus vector that contains the E.coli lacZ gene encoding beta gal was used because this vector is widely used and thought to be effective. Gene transfer was detected by X-gal staining. We hypothesized that dimethylsulfoxide and hyaluronidase, both drug delivery enhancers, would improve efficiency and that, in transfer to adventitia, direct injection would be more effective than dwelling. We studied 3 gene delivery methods to intima and media (controls, using dimethylsulfoxide and using hyaluronidase before transfection) and 2 delivery methods to adventitia (direct injection and dwelling). We used 6 rabbits per delivery method. X-gal stained positive cell rates were counted using light microscopy. Our findings indicate that (1) dimethylsulfoxide increased the efficiency of transfection to media and intima, (2) hyaluronidase increased intimal transfection efficiency, (3) direct injection to adventitia was more effective than dwelling. These findings suggest that in vein grafting, our methods are feasible for improving gene transfer efficiency.