TXB₂

Thromboxane B₂ (TXB₂) is best defined as a stable metabolite of biologically active thromboxane A₂ (TXA₂), while receptor-level signaling is mediated by the TXA₂/prostaglandin H₂ receptor (TP) rather than a distinct TXB₂ receptor^[1]. Mechanistically, TXA₂/TP signaling supports platelet activation, vascular responses, and thrombotic disease biology, and aspirin reduces thromboxane-mediated platelet activation by irreversibly inhibiting platelet COX-1^[2]. Because plasma TXB₂ can be confounded by ex vivo platelet activation, 11-dehydro-TXB₂ provides a more appropriate index of TXA₂ formation in human circulation^[3]. In disease models, urinary 11-dehydro-TXB₂ reflects thromboxane generation in diabetes, coronary artery disease, sickle cell disease, and atherosclerotic cardiovascular disease^[2][4][5]. Compared with related isoforms, human TP exists as TPα and TPβ, which arise from alternative mRNA splicing and differ in their carboxyl-terminal cytoplasmic regions^[6]. TPβ shows distinct relevance in bladder cancer, where TPβ expression promoted proliferation, migration, invasion, and poorer prognosis^[7]. For experimental applications, TXB₂ and 11-dehydro-TXB₂ are practical readouts of thromboxane biosynthesis, whereas TP antagonists or TXA₂ synthase inhibitors directly interrogate receptor signaling and pathway dependence^[8].