Platelet aggregation following exposure of phospholipase-treated platelet rich plasma to hydrogen peroxide

Hydrogen peroxide at micromolar concentrations (250–500 μM) can induce platelet aggregation of phospholipase-treated PRP. This effect, which occurs independently of the release of ADP, is blocked by aspirin, furosemide, catalase and 2-mercaptoethanol. PRP preincubated with H 2O 2 for 2–5 min. does not respond to Phl-H 2O 2 or collagen. This inhibitory effect is abolished with longer preincubations. In the presence of ADP or epinephrine, H 2O 2 enhances aggregation, if added to PRP with the inducers, and decreases the platelet response to the inducers, if preincubated with PRP for 2 min. The data suggest that micromolar concentrations of H 2O 2, which could be generated in vivo at sites of platelet plug formation by granulocytes, could influence the processes of hemostasis and thrombosis.