Endothelial Cell Dysfunction and the Pathobiology of Atherosclerosis.

Dysfunction of the endothelial lining of lesion-prone areas of the arterial vasculature is an important contributor to the pathobiology of atherosclerotic cardiovascular disease. Endothelial cell dysfunction, in its broadest sense, encompasses a constellation of various nonadaptive alterations in functional phenotype, which have important implications for the regulation of hemostasis and thrombosis, local vascular tone and redox balance, and the orchestration of acute and chronic inflammatory reactions within the arterial wall. In this review, we trace the evolution of the concept of endothelial cell dysfunction, focusing on recent insights into the cellular and molecular mechanisms that underlie its pivotal roles in atherosclerotic lesion initiation and progression; explore its relationship to classic, as well as more recently defined, clinical risk factors for atherosclerotic cardiovascular disease; consider current approaches to the clinical assessment of endothelial cell dysfunction; and outline some promising new directions for its early detection and treatment.

Vascular endothelium, hemodynamics, and the pathobiology of atherosclerosis.

The localization of atherosclerotic lesion formation to regions of disturbed blood flow associated with certain arterial geometries, in humans and experimental animals, suggests an important role for hemodynamic forces in the pathobiology of atherosclerosis. There is increasing evidence that the vascular endothelium, which is directly exposed to various fluid mechanical forces generated by pulsatile blood flow, can discriminate among these different biomechanical stimuli and transduce them into genetic regulatory programs that modulate endothelial function. In this brief review, we discuss how biomechanical stimuli generated by blood flow can influence endothelial functional phenotypes, and explore the working hypothesis of "atheroprone" hemodynamic environments as "local risk factors" in atherogenesis.

The Gordon Wilson lecture. Understanding vascular endothelium: a pilgrim's progress. Endothelial dysfunction, biomechanical forces and the pathobiology of atherosclerosis.

These are exciting times for the biomedical sciences, in general, and, in particular, for those who strive to understand the origins of complex human diseases, as we begin to focus with increasing precision on disease mechanisms at the cellular and molecular levels. Armed with the high-through-put technologies of the Post-Genomic Era, we now face the challenge of understanding biological systems at the level of their complex integration, and this will truly bring meaning to the concept of Systems Biology.

Biomechanical forces in atherosclerosis-resistant vascular regions regulate endothelial redox balance via phosphoinositol 3-kinase/Akt-dependent activation of Nrf2.

Local patterns of biomechanical forces experienced by endothelial cells (ECs) in different vascular geometries appear to play an essential role in regulating EC function and determining the regional susceptibility to atherosclerosis, even in the face of systemic risk factors. To study how biomechanical forces regulate EC redox homeostasis, an important pathogenic factor in atherogenesis, we have cultured human ECs under 2 prototypic arterial shear stress waveforms, "atheroprone" and "atheroprotective," which were derived from 2 distinct vascular regions in vivo that are typically "susceptible" or "resistant" to atherosclerosis. We demonstrate that atheroprotective flow decreases EC intracellular redox level and protects ECs against oxidative stress-induced injury.