Platelet arachidonic acid-derived eicosanoid pathway (AA pathway)

The platelet arachidonic acid-derived eicosanoid pathway is a central biochemical process that generates lipid signaling molecules essential for blood clotting and vascular tone. The pathway begins with the release of arachidonic acid from the platelet plasma membrane by phospholipase A2, followed by its conversion into unstable endoperoxides by the enzyme cyclooxygenase-1 (COX-1) [PMID: 25994911]. The primary end-product in platelets is thromboxane A2 (TXA2), a potent inducer of platelet aggregation and a strong vasoconstrictor that plays a pivotal role in arterial thrombosis [PMID: 11368173]. Because platelets are anuclear and cannot synthesize new proteins, irreversible inhibition of COX-1 by drugs like aspirin leads to a long-lasting antithrombotic effect for the lifespan of the platelet [PMID: 17303713]. This pathway is a major therapeutic target for the secondary prevention of cardiovascular events such as myocardial infarction and ischemic stroke [PMID: 22533361]. Beyond COX-1, other enzymes like 12-lipoxygenase also contribute to the production of eicosanoids like 12-HETE, which modulate inflammatory responses and vascular health [PMID: 15123330]. Dysregulation of this cascade can lead to pathological thrombus formation, contributing to the progression of atherosclerosis and acute coronary syndromes. Pharmacological modulation of this pathway remains a cornerstone of antiplatelet therapy in modern cardiology.

Other names

Arachidonic acid cascadePlatelet eicosanoid metabolismCOX-1/TXA2 pathwayProstanoid biosynthetic pathwayPlatelet AA pathway

Inhibition of cyclooxygenase-1 (COX-1) to prevent the conversion of arachidonic acid to prostaglandin H2, thereby blocking the synthesis of thromboxane A2 (TXA2). Other mechanisms include thromboxane synthase inhibition and thromboxane receptor (TP) antagonism.