Role of Endothelial Shear Stress in the Natural History of Coronary Atherosclerosis and Vascular Remodeling:

Role of Endothelial Shear Stress in the Natural History of Coronary Atherosclerosis and Vascular Remodeling: Molecular, Cellular, and Vascular Behavior

Yiannis S. Chatzizisis, Ahmet Umit Coskun, Michael Jonas, Elazer R. Edelman, Charles L. Feldman, Peter H. Stone

We summarize the molecular, cellular, and vascular processes supporting the role of low endothelial shear stress (ESS) in the natural history of coronary atherosclerosis and vascular remodeling and indicate likely mechanisms concerning the natural history of atherosclerotic plaques. Each early atherosclerotic plaque exhibits an individual natural history that is dependent not only on the progression of atherosclerosis but also on the local ESS and vascular remodeling response. An enhanced understanding of the pathobiologic processes responsible for atherosclerosis and vascular remodeling might allow for early identification of a high-risk coronary plaque, thereby providing a rationale for prevention of acute coronary syndromes.

Although the entire coronary tree is exposed to the atherogenic effect of the systemic risk factors, atherosclerotic lesions form at specific arterial regions, where low and oscillatory endothelial shear stress (ESS) occur. Low ESS modulates endothelial gene expression through complex mechanoreception and mechanotransduction processes, inducing an atherogenic endothelial phenotype and formation of an early atherosclerotic plaque. Each early plaque exhibits an individual natural history of progression, regression, or stabilization, which is dependent not only on the formation and progression of atherosclerosis but also on the vascular remodeling response. Although the pathophysiologic mechanisms involved in the remodeling of the atherosclerotic wall are incompletely understood, the dynamic interplay between local hemodynamic milieu, low ESS in particular, and the biology of the wall is likely to be important. In this review, we explore the molecular, cellular, and vascular processes supporting the role of low ESS in the natural history of coronary atherosclerosis and vascular remodeling and indicate likely mechanisms concerning the different natural history trajectories of individual coronary lesions. Atherosclerotic plaques associated with excessive expansive remodeling evolve to high-risk plaques, because low ESS conditions persist, thereby promoting continued local lipid accumulation, inflammation, oxidative stress, matrix breakdown, and eventually further plaque progression and excessive expansive remodeling. An enhanced understanding of the pathobiologic processes responsible for atherosclerosis and vascular remodeling might allow for early identification of a high-risk coronary plaque and thereby provide a rationale for innovative diagnostic and/or therapeutic strategies for the management of coronary patients and prevention of acute coronary syndromes.

Abbreviations and Acronyms: EC, endothelial cell, ECM, extracellular matrix, eNOS, endothelial nitric oxide synthase, ESS, endothelial shear stress, IEL, internal elastic lamina, IL, interleukin, LDL, low-density lipoprotein cholesterol, MAPK, mitogen-activated protein kinase, MMP, matrix metalloproteinase, NF-κB, nuclear factor-kappa B, NO, nitric oxide, ROS, reactive oxygen species, SREBP, sterol regulatory elements binding protein, TCFA, thin cap fibroatheroma, TF, transcription factor, VSMC, vascular smooth muscle cell