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 mug/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 +/- 1.00 x 10(3) mum(2), Ang II versus control; P < 0.001) that was significantly inhibited by Ad-gp91ds-eGFP (26.23 +/- 0.90 x 10(3) mu m(2); 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.