[Antioxidants and malondialdehyde during hemodialysis with cellulose diacetate and polysulfone membranes]

Free radicals (FR) may cause lipid peroxidation and damage macromolecules and cellular structure of the organism, e.g. endothelium and erythrocytes. Some studies have shown that haemodialysis is connected with increased FR production. The aim of the study was to evaluate the effects of two dialysis membranes on lipid peroxidation and some antioxidant protective factors.

The authors followed nine patients treated in a regular dialysis programme. In a cross controlled study the patients underwent haemodialysis with the use of cellulose diacetate (CDA) and polysulfone (PS) dialysis apparatus. Malondialdehyde in plasma was determined as a marker of lipid peroxidation. The haemodialysis with CDA or PS did not result in increased malondialdehyde levels in min. 30 or at the end of the procedure. The antioxidant capacity of plasma decreased after haemodialysis in a similar way with both types of membranes (PS, 1.67 +/- 0.10 mumol/l versus 1.47 +/- 0.23, P < 0.05; CDA: 1.72 +/- 0.10 versus 1.55 +/- 0.12, P < 0.05). The selenium blood level did not change. Activity of glutathione peroxidase (GSHPx) in blood before the dialysis was higher in the observation with subsequent use of CDA than while using PS (38.6 +/- 9.4 versus 34.5 +/- 6.6, P < 0.05). In the cohort with polysulfone membrane GSHPx further decreased in min. 30 of haemodialysis (34.0 +/- 6.6 IU/g Hb versus 31.1 +/- 5.0, P < 0.05). Superoxide dismutase (SOD) was also higher in dialysis with CDA membrane that while using PS (846 +/- 171 IU/g Hb versus 522 +/- 141, P < 0.05).

The activity of antioxidant enzymes GSHPx and SOD was lower with polysulfone membrane than with the cellulose acetate membrane. GSHPx activity also further decreased from min. 30 of dialysis with the PS membrane. It may be due to increased production of superoxide anion and hydrogen peroxide during haemodialysis with the PS. Lipid peroxidation has not been proved to increase during haemodialysis with the CDA or PS membrane.