Influence of different hemodialysis membranes on red blood cell susceptibility to oxidative stress

Oxidative stress is crucial in red blood cell (RBC) damage induced by activ ated neutrophils in in vitro experiments. The aim of the study was to evalu ate whether the bioincompatibility phenomena occurring during hemodialysis (HD) (where neutrophil activation with increased free radical production is well documented) may have detrimental effects on RBC. We evaluated RBC sus ceptibility to oxidative stress before and after HD in 15 patients using Cu prophan, cellulose triacetate, and polysulfone membrane. RBC were incubated with t-butyl hydroperoxide as an oxidizing agent both in the presence and in the absence of the catalase inhibitor sodium azide. The level of malonal dehyde (MDA), a product of lipid peroxidation, was measured at 0, 5, 10, 15 , and 30 min of incubation. When Cuprophan membrane was used, the MDA produ ction was significantly higher after HD, indicating an increased susceptibi lity to oxidative stress in comparison to pre-I-ID. The addition of sodium azide enhanced this phenomenon. Both cellulose triacetate and polysulfone m embranes did not significantly influence RBC susceptibility to oxidative st ress. Neither the level of RBC reduced glutathione nor the RBC glutathione redox ratio changed significantly during HD with any of the membranes used. The RBC susceptibility to oxidative stress was influenced in different way s according to the dialysis membrane used, being increased only when using the more bioincompatible membrane Cuprophan, where neutrophil activation wi th increased free radical production is well documented. The alterations fo und in this study might contribute to the reduced RBC longevity of HD patie nts where a bioincompatible membrane is used.