Procoagulant role, platelets

Schematic view of the role of coagulation factor Xa in arterial thrombosis. After endothelial injury, platelets adhere to the subendothelial matrix. The procoagulant activity of the arterial clot can be attributed to the formation of the prothrombinase complex on the platelet surface which cleaves prothrombin and produces thrombin. Thrombin subsequently acts as a strong agonist of further platelet aggregation.

Such microvesicles have size variable between 50 nm to 1 (xm and differ from other vesicles (like exosomes (30-100 nm)). In general, microparticles are phospholipids vesicles derived from eukaryotic cells as a result of different types of stimulation. Microparticles can also be defined as phospholipids microvesicles containing certain membrane proteins originating from the parental cell. Microparticles circulate in the blood and contribute to numerous physiological processes. MPs have been described in various haematopoietic cells as platelets (Heijnen et al. 1999), T-cells (Blanchard et al. 2002), polynuclear neutrophils (Mesri and Altieri 1999) or dendritic cells. After have been considered as cell dust, MPs are now considered to reflect cell activation. Platelet derived microparticles have been the most extensively studied until now. They are now accepted to play an important role in the procoagulant... 

Thrombosis is an often encountered consequence of atherosclerotic alterations of the vessel wall, and there can be no doubt that in its genesis, blood platelets play a predominant role (cf.55)< Platelets in turn are of considerable interest as the model of a metabolically active, contractile cell, capable of reacting to a variety of external stimuli. In the course of their activation, they display a series of morphological and biochemical alterations, in the course of which they aggregate and acquire procoagulant properties. It is of particular interest that lipids and fatty acids are known to interact with platelets and with the blood clotting system, and this again justifies the inclusion of a chapter on thrombosis in this series of articles on diet and atherosclerosis. ... 

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