Adenovirus-mediated extracellular superoxide dismutase gene therapy reduces neointima formation in balloon-denuded rabbit aorta.

BACKGROUND Restenosis is a frequent problem after invasive treatment of atherosclerotic vessels and is associated with intimal hyperplasia, which is primarily a result of proliferation and migration of smooth muscle cells, leading to the formation of neointima. Because there is no effective conventional medication for restenosis, gene therapy is a potential new treatment to prevent neointima formation. METHODS AND RESULTS In the present study, we analyzed the effects of adenovirus-mediated extracellular superoxide dismutase (EC-SOD) gene transfer (3x10(9) pfu/kg AdEC-SOD versus AdLacZ control virus) on neointima formation in balloon-denuded rabbit aortas. Local catheter-mediated gene transfer to the arterial wall reduced restenosis (P<0.001) and decreased the number of macrophages in the transduced segment (P<0.001) 2 weeks and 4 weeks after the gene transfer compared with AdLacZ controls. Transgene expression was detected in the arterial wall by RT-PCR 2 weeks after the procedure, and the production of superoxide anion was reduced after the gene transfer. Recovery of the endothelial layer was enhanced in EC-SOD-transduced rabbits compared with LacZ controls (P<0.001) 2 weeks after the gene transfer. The therapeutic effect was found to be extended, affecting the gene transfer site and flanking aortic segments from the renal arteries to the bifurcation. However, systemic AdEC-SOD gene transfer to liver did not have any effects on restenosis. CONCLUSIONS The results suggest that EC-SOD gene transfer reduces restenosis and may be useful for the prevention of intimal hyperplasia after vascular manipulations.