Aspirin is the mainstay of treatment for the prevention of cardiovascular disease. It acts by irreversibly inhibiting COX1 enzymes and hence blocking arachidonic acid-thromboxane pathway. Due to lack of a nucleus, platelets cannot generate new COX1 and hence COX1 is inhibited for the lifetime of platelets (8 days). Aspirin treatment results in marked decrease in the excretion of urinary metabolites of thromboxane; the residual excretion is thought to be of endothelial origin where presence of nucleus results in formation of new COX1.
Despite adequate aspirin therapy, a significant number of individuals continue to have higher platelet reactivity and incomplete inhibition of platelet function. Such individuals are also at increased risk of future cardiovascular events. However, the underlying mechanisms that result in higher residual platelet reactivity after aspirin treatment are unclear and are being extensively explored by several researchers.
To identify mechanism of aspirin resistance, this study examined the differences in proteome of 2 aspirin resistant and 4 aspirin sensitive individuals and found that the levels of glycoprotein IIIa were higher in aspirin resistant individuals than in those without aspirin resistance.
Due to small sample size, it is difficult to rule-out the possibility of a type I error, however, considering the role of glycoprotein IIIa in platelet biology, it is conceivable that protein may play a role in aspirin resistant although exact mechanism remains unknown.
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