Effects of high-flux hemodialysis on oxidant stress

Background. Neutrophil oxygen radical production is increased in end-stage renal disease (ESRD) patients and it is further enhanced during dialysis with low-flux cellulosic membranes. This increased oxygen radical production may contribute to the protein and lipid oxidation observed in ESRD patients. We tested the hypothesis that high-flux hemodialysis does not increase oxygen radical production and that it is not associated with protein oxidation. Methods. Neutrophil oxygen radical production was measured during dialysis with high-flux dialyzers containing polysulfone and cellulose triacetate membranes. Free sulfhydryl and carbonyl groups and advanced oxidation protein products were measured to assess plasma protein oxidation. Results. Pre-dialysis, neutrophil oxygen radical production was significantly greater than normal and increased significantly as blood passed through the dialyzer in the first 30 minutes of dialysis. Post-dialysis, however, neutrophil oxygen radical production had decreased and was not different from normal. Pre-dialysis, significant plasma protein oxidation was evident from reduced free sulfhydryl groups, increased carbonyl groups, and increased advanced oxidation protein products. Post-dialysis, plasma protein free sulfhydryl groups had increased to normal levels, while plasma protein carbonyl groups increased slightly, and advanced oxidation protein products remained unchanged. Conclusions. The results of this study show that neutrophil oxygen radical production normalizes during high-flux dialysis, despite a transient increase early in dialysis. This decrease in oxygen radical production is associated with an improvement in some, but not all, measures of protein oxidation.