Endothelial cell activation, injury, damage and dysfunction: separate entities or mutual terms?

The loss of well-regulated endothelial cell functioning is followed by adve rse changes in a variety of physiological systems, such as the expression o f adhesion molecules, maintenance of adequate blood vessel tone and haemost asis. Therefore, a full understanding of endothelial cell biology is essent ial if the losses of normal function of these systems are to be avoided. Th e viewpoint presented in this paper suggests that a spectrum between endoth elial cell health and disease can be drawn: midway between these two extrem es is immunological activation (by, for example, cytokines), which is rever sible. Endothelial cell damage or injury (which may be the result of chroni c inflammatory activation, hypercholesterolaemia, and/or smoking) are invar iably associated with clinical conditions such as hypertension and oedema ( and, ultimately, thrombosis and infarction), and are more difficult to reve rse. A better understanding of the events, including apoptosis, that lead t o vascular dysfunction may be useful in developing our understanding of vas cular biology. Blood Coagul Fibrinolysis 11:623-630 (C) 2000 Lippincott Wil liams & Wilkins.