Gene transfer of endothelial nitric oxide synthase but not Cu/Zn superoxide dismutase restores nitric oxide availability in the SHRSP

Objective: Previous studies from our group have shown a deficit in nitric o xide (NO) bioavailability and an excess production of the superoxide anion (O-2(-)) in the stroke prone spontaneously hypertensive rat (SHRSP) compare d to the normotensive Wistar Kyoto (WKY) strain. This present study has inv estigated whether adenoviral-mediated gene transfer of human eNOS or Cu/ZnS OD can alter the NO/O-2(-) balance, thereby improving endothelial function. Methods: A recombinant adenovirus, Ad/Hu/eNOS, containing the human eNOS c DNA fragment was generated by homologous recombination in 293 cells. Ad/Hu/ eNOS or Ad/Cu/ZnSOD was delivered into SHRSP carotid arteries in vivo, usin g a titre of 2x10(9)-2x10(10) plaque forming units (pfu)/ml, and the effect on gene expression was observed 24 h later. Results: Western blotting conf irmed increased enzyme levels of eNOS and Cu/ZnSOD in the viral-infused ves sels. Ex vivo, the presser response to phenylephrine (PE) in the presence o f L-NAME was increased in the eNOS-infused arteries relative to the contral ateral controls, indicating restoration of basal NO availability to that ob served in untreated control WKY rats. Infusion of the SOD virus produced a statistically insignificant increase in NO bioavailability. Conclusions: Ou r results support our previous findings obtained using a bovine eNOS recomb inant adenovirus, that recombinant adenoviral gene transfer of human eNOS h as a significant effect on NO bioavailability. In contrast, AdCu/ZnSOD gene transfer does not elicit an effect in our model. These results indicate th at short-term overexpression of a recombinant eNOS, but not Cu/ZnSOD gene, in carotid arteries of the SHRSP is an effective means of locally increasin g NO bioavailability to improve endothelial function. (C) 2000 Elsevier Sci ence BN. All rights reserved.