The effects of iloprost infusion on microcirculation is independent of nitric oxide metabolites and endothelin-1 in chronic peripheral ischaemia

Background Endothelial vascular tone modulators are thought to be involved in aetiopathogenesis of systemic sclerosis (SS) and of peripheral artery oc clusive disease (PAOD). Iloprost, a prostacyclin (PGI,) analogue, induces c linical benefit in patients suffering from peripheral ischaemia. This study was performed to investigate the effect of this drug on endothelial functi on in vivo to elucidate the role of vascular tone modulators. Methods Fourteen PAOD and 15 SS patients were treated for 24: and 10 days r espectively On the first day, before and after therapy, nitric oxide metabo lites (NO2-/NO3-) and endothelin-l (ET-1) plasma concentrations were detect ed; moreover, the endothelium-dependent vasodilatation in response to artif icial ischaemia was evaluated by means of an echo-Doppler device. Results The echo-Doppler evaluation showed that the percentage of arterial reactive dilatation was not modified by placebo or by iloprost, and that th e increase in blood velocity flow lasted for a significant longer time afte r drug infusion (226.79 +/- 17.49 vs. 310.71 +/- 36.32 s; P > 0 04). NO2-/N O3- and ET-1 plasma concentration were higher in patients than in control s ubjects (P < 0.004). After 6 h of iloprost infusion, no significant modific ations were detected. Conclusion This study provides evidence that iloprost enhances the microvas cular functional capacity and clinical benefit for patients. The effects of the drug seem to be independently or not directly correlated with its inte ractions with vascular tone modulators such as NO2-/NO3- or ET-1.