Release of platelet constituents by monosodium urate crystals

Abstract

The release of human platelet constituents by the etiologic agent of gout, the monosodium urate crystal, is described. In suspensions of washed platelets, response to urate crystals proceeded in 2 phases: A secretory phase involved the rapid active release of serotonin, ATP, and ADP with little loss of lactic dehydrogenase or β-glucuronidase. A lytic phase involved the slower loss of all platelet constituents. Both phases were inhibited by iodoacetate plus dinitrophenol, suggesting an energy requirement. In ultrastructural studies, lysis of washed platelets which appeared to contain crystals was seen. Urate crystals were also shown to induce serotonin release and platelet lysis in citrated platelet-rich plasma. Since urate crystals are deposited at a variety of sites, urate crystal-platelet interaction in vivo is a possibility. Such interactions, leading to release of platelet constituents, might contribute to gouty inflammation or to enhanced atherogenesis.