Endothelial dysfunction

In blood vessel diseases, endothelial dysfunction is an unhealthy state of the the cells that line the blood vessels (endothelium). The main cause of endothelial dysfunction is impaired bioavailability of nitric oxide.

In addition to acting as a semipermeable membrane, the endothelium is responsible for maintaining vascular tone and regulating oxidative stress by releasing mediators, such as nitric oxide, prostacyclin and endothelin, and by controlling local angiotensin-II activity.

Dysfunctional endothelium is characterized by constricted blood vessels, increased ability of chemicals to flow through blood vessel walls, blood clots, and inflammation. This pathological state is often associated with elevated levels of biomarkers such as prothrombin time, D-dimer, von Willebrand factor, fibrin degradation products, C-reactive protein (CRP), ferritin, Interleukin 6 (IL-6), and plasma creatinine. The result of this endothelial dysregulation is a cascade of harmful effects, including tightened blood vessels, small blood vessel leakage, blood clots, high levels of inflammation, and a disrupted immune response against viruses. These changes contribute to the progression of blood vessel (vascular) diseases.

In a healthy state, the endothelium exhibits wider blood vessels, tightly-controlled blood vessel permeability, and anti-thrombotic and anti-inflammatory properties. This balance ensures the smooth functioning of the vascular system.