The effects of the nitric oxide donors molsidomine and SIN-1 on human polymorphonuclear leucocyte functionin vitro andex vivo

Abstract

The nitrovasodilator and nitric oxide donor molsidomine and its metabolite SIN-I dilate vascular smooth muscle and inhibit platelet activation by increasing intracellular concentrations of cyclic GMP We have therefore studied the effects of molsidomine and SIN-I on isolated human polymorphonuclear leucocytes (PMN)in vitro andex vivo. In vitro molsidomine dose-dependently reducedβ-glucuronidase release and the generation of superoxide anions from non-activated and from FMLP- or PAF-stimulated human PMNs. SIN-1 was equally effective in reducing (β-glucuronidase release and totally inhibited oxygen radical generation at a concentration of 580 μmol · l⁻¹. In a double-blind, placebo-controlled, randomized trial we also studiedβ-glucuronidase release and the generation of superoxide anions from isolated PMNs. Blood was drawn from 12 healthy volunteers before and 3 h after oral molsidomine (16 mg) or placebo. There was no statistically significant difference inβ-glucuronidase release and superoxide anion formation when the PMNs were isolated before or after molsidomine or placebo. This was the case for non-activated, as well as FMLP- or PAF-stimulated PMNs. Thus, the nitric oxide donors molsidomine and its metabolite SIN-I caused a dose-dependent inhibition of PMN functionsin vitro, but no significant inhibition when the PMNs were isolated after oral molsidomine.