A novel free radical scavenger, nicaraven, inhibits human platelet aggregation in vitro.

The present study was undertaken to investigate whether or not radical scavengers can inhibit platelet aggregation in humans. Toward this end, nicaraven was selected for this study because it has been shown to specifically scavenge hydroxyl radicals that are implicated in platelet aggregation. Ten healthy volunteers and 10 patients with cerebral thrombosis were enrolled in this study. The antiplatelet activities in vitro of nicaraven were examined. The concentrations of nicaraven tested were 3.50 x 10(-5) mol/L, 1.75 x 10(-4) mol/L, 3.50 x 10(-4) mol/L, and 1.75 x 10(-3) mol/L, respectively. The maximum aggregation rate induced by adenosine diphosphate (ADP) was significantly inhibited by nicaraven at concentration ranges of 3.50 x 10(-4) mol/L or higher in the healthy volunteer platelets. The maximum aggregation rate induced by collagen was significantly inhibited by 1.75 x 10(-3) mol/L of nicaraven. Using platelets from patients with cerebral thrombosis, the maximum aggregation rate induced by ADP was significantly inhibited by 1.75 x 10(-3) mol/L of nicaraven. Furthermore, the maximum aggregation rate induced by collagen were significantly reduced by 1.75 x 10(-3) mol/L of nicaraven. Nicaraven induces dose-dependent inhibition of platelet aggregation in both healthy volunteers and patients with cerebral thrombosis.