The endothelium and its role in regulating vascular tone

Abstract

The endothelium forms an important part of the vasculature and is involved in promoting an atheroprotective environment via the complementary actions of endothelial cell-derived vasoactive factors. Disruption of vascular homeostasis can lead to the development of endothelial dysfunction which in turn contributes to the early and late stages of atherosclerosis. In recent years an increasing number of non-invasive vascular tests have been developed to assess vascular structure and function in different clinical populations. The present review aims to provide an insight into the anatomy of the vasculature as well as the underlying endothelial cell physiology. In addition, an in-depth overview of the current methods used to assess vascular function and structure is provided as well as their link to certain clinical populations.

Keywords: Atherosclerosis; Cardiovascular Disease; Endothelial Dysfunction; Endothelium; Macrovascular.; Microvascular; Nitric Oxide; Smooth muscle.

Fig. (1)

Endothelial nitric oxide production and it actions in the vascular smooth muscle cell. ACh= acetylcholine; BK= bradykinin; ATP= adenosine triphosphate; ADP= adenosine diphosphate; SP= substance P; SOCa²⁺= store-operated Ca²⁺ channel; ER= endoplasmic reticulum; NO= nitric oxide; sGC= soluble guanylyl cyclase; cGMP= cyclic guanosine-3’, 5-monophosphate; MLCK= myosin light chain kinase. *When Ca²⁺ stores of the endoplasmic reticulum are depleted a signal is sent to SOCa²⁺ channel which allows extracellular Ca²⁺ into the endothelial cell.

Fig. (2)

An overview of the assessments for endothelial function and vascular structure performed in different vascular beds. ACh = Acetylcholine, SNP = Sodium nitroprusside.