Gene transfer of endothelial nitric oxide synthase (eNOS) in eNOS-deficient mice.

Relaxation to acetylcholine (ACh) and calcium ionophore (A-23187) is absent in aortas from endothelial nitric oxide synthase (eNOS)-deficient (eNOS -/-) mice. We hypothesized that gene transfer of eNOS would restore relaxation to ACh and A-23187 in eNOS -/- mice. Aortic rings from eNOS -/- and eNOS +/+ mice were exposed in vitro to vehicle or adenoviral vectors encoding beta-galactosidase (lacZ) or eNOS. Histochemical staining for beta-galactosidase and eNOS demonstrated transduction of endothelial cells and adventitia. Vehicle-treated vessels from eNOS -/- mice did not relax to ACh or A-23187 compared with eNOS +/+ mice. In contrast, relaxation to nitroprusside (NP) was significantly greater in eNOS -/- mice than in eNOS +/+ mice. Gene transfer of eNOS, but not lacZ, to vascular rings of eNOS -/- mice restored relaxation to ACh and A-23187. In vessels from eNOS -/- mice that were transduced with eNOS, N(omega)-nitro-L-arginine (10(-4) M) inhibited relaxation to ACh and A-23187 but not NP. Thus vascular function can be significantly improved by gene transfer in vessels where a major relaxation mechanism is genetically absent.