Infections and endothelial cells.

Systemic infection by various pathogens interacts with the endothelium and may result in altered coagulation, vasculitis and atherosclerosis. Endothelium plays a role in the initiation and regulation of both coagulation and fibrinolysis. Exposure of endothelial cells may lead to rapid activation of coagulation via tissue factor (TF) expression and the loss of anticoagulant properties by impairment of antithrombin III, TF pathway inhibitor (TFPI) and the protein C system. Endothelial-derived plasminogen activator inhibitor (PAI) is essential for the regulation of fibrinolysis and impaired endothelial function leads to imbalance in fibrinolysis, resulting in a procoagulant state. The interaction between inflammation and coagulation, soluble adhesion molecules and circulation endothelial cells is important in the pathogenesis of an unbalanced haemostatic system. Rather than being a unidirectional relationship, the interaction between inflammation and coagulation appears to be significant. In the crosstalk, the endothelium is playing a pivotal role.