Angiotensin-Converting Enzyme Inhibition Prevents Arterial Nuclear Factor-κB Activation, Monocyte Chemoattractant Protein-1 Expression, and Macrophage Infiltration in a Rabbit Model of Early Accelerated Atherosclerosis

Abstract

Background The migration of monocytes into the vessel wall is a critical event leading to the development of atherosclerosis. Monocyte chemoattractant protein-1 (MCP-1) is the main chemotactic factor involved in this phenomenon, and nuclear factor-κB (NF-κB) is one of the nuclear factors controlling its expression. ACE inhibitors have been useful in some experimental models of atherosclerosis. In this work, we addressed the hypothesis that angiotensin II (Ang II) may be implicated in the recruitment of monocytes into the vessel wall through the activation of NF-κB and the induction of MCP-1 expression. Methods and Results Accelerated atherosclerosis was induced in the femoral arteries of rabbits by endothelial desiccation and atherogenic diet for 7 days. Atherosclerotic vessels exhibited an increase in NF-κB–like activity, and p50 and p65 NF-κB subunits were identified as components of this activity. MCP-1 (mRNA and protein) was also expressed in the injured vessels coincidently with the neointimal macrophage infiltration. ACE inhibition with quinapril reduced these three parameters. In cultured monocytic and vascular smooth muscle cells, Ang II elicited an increase in NF-κB activation and MCP-1 expression that was prevented by preincubation of cells with pyrrolidinedithiocarbamate, an inhibitor of NF-κB activation. Conclusions The present data support a role for Ang II in neointimal monocyte infiltration through NF-κB activation and MCP-1 expression in a model of accelerated atherosclerosis in rabbits. Our results suggest that ACE inhibitors may have a beneficial effect in early atherosclerosis.