Dietary lipid lowering modifies plaque phenotype in rabbit atheroma after angioplasty: a potential role of tissue factor.

Abstract

Tissue factor (TF), the main initiator of blood coagulation, is involved in cellular migration and angiogenesis processes. TF is expressed strongly in lipid-rich plaques and probably plays an important role in the thrombotic complications of plaque rupture. This study analyzes the effect of dietary lipid lowering on TF expression and cellular modifications in angioplasty-induced rabbit plaque rupture. After experimental plaque rupture by balloon angioplasty in atheromatous rabbits, animals were assigned a 0.2% or a 2% cholesterol diet, and the TF content of arterial wall and the associated histological modifications were analyzed after 4 weeks. Early effects of lipid lowering were observed: The increase of TF expression in the vascular wall was stronger in the 2% than in the 0.2% cholesterol diet group (iliac arteries: 1226+/-308 versus 72+/-29 mU TF/g artery, P<0.005). Immunohistochemistry indicated that TF expression was associated with sprout of neovessels, which was more pronounced in the 2% than in the 0.2% cholesterol group. This study shows that dietary lipid lowering decreases the thrombotic potential of ruptured atherosclerotic plaques through TF decrease. Moreover, high TF expression is associated with marked angiogenesis in the vascular wall, which is reduced by lipid lowering. These results provide further arguments for strong dietary lipid lowering to reduce plaque instability and thrombogenicity.