Effect of different dialysis membranes on endogenous antioxidant enzyme activity and lipid peroxidation in haemodialysis patients

ABSTRACT

This work aimed to clarify the most suitable type of the haemodialysis membranes in order to minimize the disequilibrium between the levels of oxidant and antioxidant factors in haemodialysis patients. This study was conducted on 79 subjects who were classified into 5 groups The 1st group included 14 apparently healthy volunteers, the 2nd group included 13 patients with end stage renal disease [ESRD] just before the beginning of haemodialysis treatment [predialysis], the 3rd group included 18 patients with ESRD on maintenance haemodialysis using dialyzers equipped with cuprophane membrane, the 4th group included 14 patients using polysulphone membrane and the 5th group included 20 patients using hemophane membrane. All participants were subjected to thorough clinical examination and laboratory investigations [estimation of superoxide dismutase [SOD], glutathione peroxidase [GPx], catalase and lipids peroxides [MDA + 4-HNE], serum urea, creatinine, uric acid, fasting and postprandial blood sugar, haemoglobin, haematocrit, creatinine clearance and protein 24 hours urine]. The results revealed that serum lipid peroxides [MDA and 4-HNE] were significantly increased in all patients groups compared to the control group and more significantly elevated in the 3 dialyzed groups compared to the predialysis and alsosignificantly higher in the cuprophane group when compared to the other 2 membranes [polysulphone and haemophane]; while no significant change was detected between the haemophane and the polysulphone groups. There were significantly decreased levels of endogenous antioxidant enzymes [SOD, GPx and plasma catalase] in all patients when compared to the control group. SOD and catalase were significantly lower in the dialyzing groups when compared to the predialysis one; while GPx showed significant decrease only on using cuprophane membrane but not with polysulphone and haemophane. Significant negative correlation between serum lipid peroxides and each of the three antioxidant enzymes was found. Positive correlation existed between haemoglobin concentration, haematocrit and antioxidant enzyme activities. This study confirmed the presence of disequilibrium between the oxidative stress and the antioxidant protective enzymes in uraemic patients; this permanent oxidative stress could act as important mediator to the progression of renal failure and to associated complications such as anaemia and atherosclerosis. This disequilibrium is maximally enhanced by the use of incompatible membranes [cuprophane], while it is significantly reduced on using biocompatible ones [polysulphone and haemophane]. Consequently, in view of the results, the universal use of biocompatible membranes for haemodialysis in a trial to decrease the hazardous effects of haemodialysis is recommended