Early increase in blood nitric oxide, detected by electron paramagnetic resonance as nitrosylhaemoglobin, in haemodialysis

The objective of this study was to determine Key words: nitric oxide; biocompatibility; dialysisintradialytic blood levels of nitric oxide (NO), membranes; electron paramagnetic resonancein patients undergoing chronic haemodialysis. Thiswas done by detection of nitrosylhaemoglobinby a sensitive technique of spin trap electron paramag- Introduction netic resonance at 0, 5, 15, 60, 180 and 240 minof a 4-h standard bicarbonate dialysis, using the same Vascular endothelial cells [1] and several other celldose (6000 U) of heparin and different dialysis mem- lines, including phagocytes [2], synthesize and releasebranes. The study group included 12 patients treated nitric oxide (NO). NO counterbalances the vasocon-with cellulose-derived dialysis membranes (nine with strictor action of endothelin (ET-1) and inhibits ET-1cuprophan and three with cellulose triacetate) production via a cGMP-dependent pathway [3,4].and 10 patients treated with synthetic membranes (five Evidence of a role for NO in diverse physiologic andpathologic processes is emerging [2]. The capability ofwith polysulfone and five with polymethylmethacryl-this molecule to oxidize critical compounds, i.e. thiols,ate). Control groups included 11 normal subjectshaeme groups and iron sulphurs, sustains its involve-and six patients with end-stage renal failure who werement in different biological processes. Besides vasodil-receiving intermittent peritoneal dialysis. Basal bloodatation, its functions include inhibition of plateletlevels of nitrosylhaemoglobin in haemodialysis patientsaggregation and modulation of inflammatory andwere significantly higher than normals, but similarimmune processes [2,5,6].to peritoneal dialysis patients. A significant increase Plasma concentrations of arginine, the endogenous(P