Mechanisms of Erosion of Atherosclerotic Plaques

Abstract

Purpose of review

This review explores the mechanisms of superficial intimal erosion, a common cause of thrombotic complications of atherosclerosis.

Recent findings

Human coronary artery atheroma that give rise to thrombosis due to erosion differ diametrically from those associated with fibrous cap rupture. Eroded lesions characteristically contain few inflammatory cells, abundant extracellular matrix, and neutrophil extracellular traps (NETs). Innate immune mechanisms such as engagement of Toll-like receptor 2 (TLR2) on cultured endothelial cells (EC) can impair their viability, attachment, and ability to recover a wound. Hyaluronan fragments may serve as endogenous TLR2 ligands. Mouse experiments demonstrate that flow disturbance in arteries with neointimas tailored to resemble features of human eroded plaques disturbs EC barrier function, impairs EC viability, recruits neutrophils, and provokes EC desquamation, NET formation, and thrombosis in a TLR2-dependent manner.

Summary

Mechanisms of erosion have received much less attention than those that provoke plaque rupture. Intensive statin treatment changes the characteristic of plaques that render them less susceptible to rupture. Thus, erosion may contribute importantly to the current residual burden of risk. Understanding the mechanisms of erosion may inform the development and deployment of novel therapies to combat the remaining atherothrombotic risk in the statin era.