Increased Balloon-Induced Inflammation, Proliferation, and Neointima Formation in Apolipoprotein E (ApoE) Knockout Mice

Background and Purpose— The pathophysiology of vascular lesions after balloon angioplasty remains poorly understood. A major limitation of most experimental studies in this regard is that injury was assessed in healthy arteries. Our aim was to study the effects of hypercholesterolemia in a mouse vascular injury model that mimics human balloon angioplasty. Methods— Carotid balloon distension was performed in wild-type (WT) mice on a normal diet (ND), in apolipoprotein E–deficient (ApoE−/−) mice on ND and in ApoE−/− mice fed a high cholesterol diet (CD). Results— Medial cell death (TUNEL) was elevated in all mice at 1 hour and 1 day after angioplasty without differences between the groups. We found enhanced intimal inflammation (%CD45-positive cells) and vascular cell adhesion molecule-1 expression at 7 days (P<0.05; n≥4) as well as increased proliferation rates (BrdU-index) in ApoE−/− CD at 7 and 28 days postinjury (P<0.05; n≥5). Four weeks after injury, these events led to enhanced neointima in ApoE−/− CD...