Effects of a vitamin E-modified dialysis membrane on neutrophil superoxide anion radical production

Activation of neutrophil by the dialysis membrane and peroxidative stress plays an important role on the pathogenesis of complications in hemodialysis (HD) patients. Vitamin E is one of the potent scavengers for reactive oxygen species. Recent studies suggest that a vitamin E-modified multilayer membrane (Excebrane, CL-EE dialyzer) has an inhibitory effect on serum lipids peroxidation in HD patients. To determine the effect of CL-EE on biocompatibility in clinical use, we measured the superoxide anion radical producing ability (SOPA) of polymorphonuclear leukocytes (PMNLs), the plasma hydroxyl radical producing ability (OHPA) and superoxide anion radical scavenging activity (SSA). SOPA was measured after stimulation of PMNLs with phorbol myristate acetate using electron paramagnetic resonance (EPR) method. Plasma OHPA and SSA were also determined using the EPR method. In addition, the plasma concentrations of malondialdehyde (MDA) and oxidized low-density lipoprotein (LDL), as the parameters for lipid peroxidation, were measured. SOPA was decreased in patients who used conventional filter membrane compared with healthy controls. In the patients using the CL-EE membrane, SOPA gradually increased and reached control levels after six months. However, no significant increase was observed in patients who used a conventional filter membrane. OHPA of HD patients was significantly decreased compared with controls. In the CL-EE membrane patient group, OHPA was significantly increased at six months. SSA was significantly higher in the conventional filter membrane group than controls. In the CL-EE membrane patient group, SSA gradually decreased at six months. Plasma MDA and oxidized LDL levels were significantly higher in HD patients compared with controls. These values slowly decreased, and significant differences were found after nine months of using the CL-EE membrane. These findings suggest that activation of PMNLs and plasma OHPA and SSA in HD patients is attenuated by antioxidant effects of the CL-EE.