Gene transfer of NAD(P)H oxidase inhibitor to the vascular adventitia attenuates medial smooth muscle hypertrophy.

We previously showed that a systemic inhibitor of gp91(phox) (nox2)-based NAD(P)H oxidase abolishes angiotensin II (Ang II)-induced vascular hypertrophy. In the present study, we tested whether perivascular transfection with Ad-gp91ds-eGFP (an adenoviral bicistronic construct targeting NAD(P)H oxidase in fibroblasts) or controls Ad-CMV-eGFP and Ad-scrmb-eGFP would affect medial hypertrophy in response to Ang II. In C57BL/6J mice, we applied Ad-gp91ds-eGFP or controls to the left carotid adventitia, and 2 days later we implanted minipumps delivering vehicle or Ang II (750 microg/kg per day) for 7 days. None of the viral treatments affected Ang II-induced systolic blood pressure elevation. Immunohistochemical staining showed marker eGFP in adventitial fibroblasts and some macrophages, indicating expression of the gp91ds inhibitor. As expected, Ang II induced medial hypertrophy (medial cross-sectional area, 32.96+/-2.04 versus 20.57+/-1.00x10(3) microm2, Ang II versus control; P<0.001) that was significantly inhibited by Ad-gp91ds-eGFP (26.23+/-0.90x10(3) microm2; P<0.01) but not control viruses. Application of viruses alone did not change medial size under control conditions. Immunohistochemical staining and semiquantitative analysis showed a 70% increase in reactive oxygen species levels measured by the lipid peroxidation byproduct 4-hydroxynonenal (4-HNE) throughout the carotid wall in the Ang II group versus vehicle. After treatment with Ad-gp91ds-eGFP, 4-HNE generation was normalized. Thus NAD(P)H oxidases in adventitial fibroblasts and macrophages appear to modulate Ang II-induced medial hypertrophy.