Fig. 2.

The role of endothelial cells in regulating thrombosis. Under normal physiological conditions, ECs secrete Prostacyclin (PGI2) and nitric oxide (NO), which are important for the regulation of blood coagulation and platelet functions by synergistically increasing cAMP content in platelets. Ecto-nucleotidase derived from ECs hydrolyze ATP and ADP to AMP and adenosine, which also reduces platelet aggregation. In addition to the factors above, ECs also inhibit thrombosis by inactivating coagulation factors and inhibiting thrombin activity [80]. When endothelium is damaged, negatively charged extracellular matrix（ECM）such collagen exposed to blood, result in accumulation of platelets, von Willebrand factor (vWF) and red blood cells (RBCs), eventually lead to the formation of thrombus [15].