Vascular Endothelium in Health and Disease: Structure, Function, Assessment and Role in Metabolic Disorders

The vascular endothelium is responsible for regulating vascular tone, maintaining fluid homeo-stasis, and preventing platelet aggregation, exhibits regulatory properties in vasorelaxation and vasoconstriction - it produces, among others, nitric oxide and endothelin. The imbalance of vasoactive molecules leads to the loss of their function, known as endothelial dysfunction. Impaired endothelial function is observed in people with metabolic disorders, often preceding the onset of the disease by several years. Endothelial function assessment can be performed using invasive (eg coronary angiography) and non-invasive (flow-dependent dilation, biochemical markers) techniques. Among metabolic abnormalities, increasing scientific interest has focused on metabolic obesity in normal-weight individuals. People with this type of obesity, despite having a normal body mass index, exhibit both metabolic abnormalities typical of obesity (including hypertension and type 2 diabetes) and endothelial dysfunction. This comprehensive review summarizes the current knowledge of the structure and function of the vascular endothelium, methodologies for assessment, and pathophysiological mechanisms of endothelial dysfunction in metabolic disorders, with particular emphasis on diagnostic approaches and clinical implications for cardiovascular risk stratification.