Adeno-associated virus-mediated transfer of endothelial nitric oxide synthase gene reduces the vasoconstrictive response.

BACKGROUND: Adeno-associated virus (AAV) has a number of attractive features for gene therapy including the ability to transduce nondividing cells and long term transgene expression.
OBJECTIVE: To investigate whether the endothelial constitutive nitric oxide synthase (ecNOS) gene can be efficiently introduced into rat aortic segments using AAV vectors and thereby modulate the vasoconstrictive response. ANIMALS AND METHODS: Excised rat aortas were incubated with medium containing ecNOS-expressing AAV vectors (AAV-ecNOS). Expression of ecNOS in the aortic segments was evaluated by immunohistochemical staining. The isometric tension of the aortic segments transduced with AAV-ecNOS was measured.
RESULTS: Adventitial cells in rat aortic segments were efficiently transduced with AAV-ecNOS. The vasoconstrictive response induced by 30 mmol/L K(+) was enhanced in endothelium-denuded aortic segments compared with intact aortic segments. However, in endothelium-denuded aortic segments transduced with AAV-ecNOS, the enhancement of the vasoconstrictive response disappeared. This effect induced by ecNOS gene transfer was abolished in the presence of the nitric oxide synthase inhibitor N(G)-monomethyl-l-arginine acetate.
CONCLUSIONS: These results show that ecNOS gene transfer using AAV vectors abolishes the pathological enhancement of the vasoconstrictive response in endothelium-denuded aortic segments.