Recent Developments in Vascular Adventitial Pathobiology

Abstract

The adventitia, the outer layer of the blood vessel wall, may be the most complex layer of the wall and may be the master regulator of wall physiology and pathobiology. This review proposes a major shift in thinking to apply a functional lens to the adventitia rather than only a structural lens. Human and experimental in vivo and in vitro studies show that the adventitia is a dynamic microenvironment in which adventitial and perivascular adipose tissue cells initiate and regulate important vascular functions in disease, especially intimal hyperplasia and atherosclerosis. Although well away from the bloodwall interface, where much pathology has been identified, the adventitia has a profound influence on the population of intimal and medial endothelial, macrophage, and smooth muscle cell function. Vascular injury and dysfunction of the perivascular adipose tissue promote expansion of the vasa vasorum, activation of fibroblasts, and differentiation of myofibroblasts. This regulates further biologic processes, including fibroblast and myofibroblast migration and proliferation, inflammation, immunity, stem cell activation and regulation, extracellular matrix remodeling, and angiogenesis. A debate exists as to whether the adventitia initiates disease or is just an important participant. We describe a mechanistic model of adventitial function that brings together current knowledge and guides the design of future investigations to test specific hypotheses on adventitial pathobiology.

The Impact of Dietary Supplementation of Whole Foods and Polyphenols on Atherosclerosis

“…The outermost layer is the tunica adventitia, which is comprised of connective tissue and is crucial for arterial health. The dysfunction of this layer contributes to vascular disease, as was recently discussed by Tinajero et al [76].…”

Identification of Transcriptional Variation in Aortic Remodeling Using a Murine Transverse Aortic Constriction (TAC) Model

“…In principle, when hemodynamic changes occur, the shear force decreases, leading to the activation of vascular endothelial cell signaling transduction. This then induces a cascade of downstream responses, such as medial smooth muscle cells and adventitial fibroblasts morphological transformation, infiltration of early inflammatory cells by adventitial cells (31)(32)(33). During this process, smooth muscle cells are switched from contractile types to synthetic types, which is the iconic event of vascular remodeling (34)(35)(36).…”

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