aggregation
Last reviewed 01/2018
Aggregation describes the accumulation of platelets in large numbers at the site of damage to form a haemostatic plug - the thrombus. It is the result of increased numbers of platelets arriving at the site, being rapidly activated, and interlinking via their pseudopodia.
Platelet activating factor, 5-HT, thrombin, ADP and thromboxane all contribute to the cascade. Initially, platelets are loosely bound by a fibrinogen cross-link; this is reinforced by thrombospondin.
Aggregation seems dependent on the close interaction of local arachidonic acid metabolites which aspirin modulates to therapeutic advantage.