Increased thromboxane biosynthesis in patients with polycythemia vera: Evidence for aspirin-suppressible platelet activation in vivo

Abstract

Increased thromboxane (TX) production and modified aspirin sensitivity has been detected in vitro in platelets isolated from patients with polycythemia vera. To verify the relevance of these capacity-related measurements to the actual rate of TXA2 biosynthesis in vivo and its suppression by oral aspirin, we have investigated the urinary excretion of major enzymatic metabolites of TXB2 in 17 patients with polycythemia vera and 23 gender- and age-matched controls. Urinary 11-dehydro-TXB2 and 2,3-dinor-TXB2 were measured by previously validated radioimmunoassays. In addition, urinary immunoreactive leukotriene (LT) E4 was measured to explore the 5-lipoxygenase pathway of arachidonate metabolism. Polycythemic patients had significantly (P