Immunohistochemical analysis of Ad.hVEGF-A– and Ad.empty-transduced plaques on plaque composition and stability. The content was calculated as percentage of stained area relative to the total plaque size. (A) In Ad.hVEGF-A–treated plaques, MoMa2 staining, and thus macrophage content, was markedly increased by 40% (P = .014). (B) Analysis of Oil Red O–stained sections reveals a 66% increase in lipid content in Ad.hVEGF-A–treated plaques (P = .012). (C) Picro-sirius red–stained sections from Ad.empty controls and Ad.hVEGF-A–treated plaques. VEGF-A overexpression led to a significant decrease of 33% in plaque collagen content (P = .013). Error bars indicate SD.