We tested the effects of overexpression of the endothelial nitric oxide synthase (eNOS) gene in the normal arterial wall by adenoviral-mediated gene transfer. Rabbit carotid arteries were surgically isolated and exposed to adenoviral vectors encoding eNOS (AdeNOS) or beta-galactosidase (Ad beta Gal) on the contralateral side. Vector solutions at a concentration of 1 x 10 plaque forming units/mL were instilled for 20 minutes before restoration of flow. Arteries were harvested 4 days later for immunostaining, measurement of cGMP, and vasomotor studies. Endothelium-specific gene transfer was confirmed by staining for beta-galactosidase in the Ad beta Gal arteries. Immunostaining of en face endothelial cell imprints from AdeNOS-transduced arteries with a monoclonal antibody to eNOS showed increased immunoreactivity. Basal cGMP levels were significantly greater in the AdeNOS-transduced arteries (18.4 +/- 4.6 versus 4.2 +/- 0.5 pmol/mg protein; P < .05). Contractions to phenylephrine were significantly reduced in the AdeNOS-transduced arteries (area under curve, 106 +/- 5 versus 119 +/- 7; P < .05), but in the presence of the eNOS inhibitor, NG -monomethyl-L-arginine (L-NMMA, 3 x 10-4 mol/L), there was no difference between the two (area under curve, 148 +/- 5 versus 153 +/- 6; P = NS). Relaxations to acetylcholine obtained during submaximal contractions to phenylephrine were significantly enhanced in the AdeNOS-transduced arteries (EC50, 7.45 +/- 0.05 versus 7.23 +/- 0.03; P < .05). We conclude that overexpression of eNOS in the endothelium results in diminished contractile responses, as well as enhanced endothelium-dependent relaxations. These findings imply a possible role for vascular eNOS gene transfer in the treatment of vasospasm and endothelial dysfunction. (Hypertension. 1997;30[part 1]:314-320.).
ASJC Scopus subject areas
- Internal Medicine