The significance of endothelial heterogeneity in thrombosis and hemostasis.

The endothelium is recognized today as a functional and dynamic component of the body that plays an important part in health and disease. This article briefly reviews the role of endothelium in thrombosis and hemostasis. There is a paradigm shift from one that regards the endothelium as one single entity to the concept that the endothelium is heterogeneous. Thrombotic complications in many disorders show a predilection to specific locations, despite the fact that a hypercoagulable state affects the entire body. Likewise, bleeding is more commonly encountered in certain anatomical locations than in others. Recent observations of the heterogeneous distribution of coagulation and fibrinolytic factors in the endothelium and the adaptation of the endothelium to various stimuli may provide an explanation for the diverse phenotypes. Recognition of this changing paradigm is helpful to for the diagnosis and management of bleeding and thrombotic complications. It also helps in the understanding of the pathogenesis of many bleeding and thrombotic disorders, and in the development of new drug designs for site-specific therapy.