Blood oxidative stress and lipoprotein oxidizability in haemodialysis patients: effect of the use of a vitamin E-coated dialysis membrane

Background. Oxidative stress has been shown in haemodialysis patients in re lation with an increased production of free radicals due to membrane-induce d complement and leukocyte activation. In order to minimize membrane bioinc ompatibility and thereby oxidative stress, more compatible filters have bee n perfected. Among them, a high-flux vitamin E-coated membrane (CL-EE) has been proposed recently. In vivo, little data is available on the consequenc es of the use of vitamin E-coated membranes. In the present study, the effe cts of a 3-month use of CL-EE dialysis membranes compared to conventional m embranes have been evaluated in 12 haemodialysis patients on the blood oxid ative stress status before and after the dialysis session. Methods. We determined the lipid peroxidation status (plasma thiobarbituric acid-reactive substances) and antioxidant defence (erythrocyte Cu,Zn-super oxide dismutase and plasma and erythrocyte glutathione peroxidase activitie s, plasma vitamin E, beta -carotene, vitamin A and total antioxidant status ). Also, we simultaneously determined the antioxidant content and the coppe r oxidizability of isolated low density- and high density-lipoproteins (LDL s and HDLs). Results. The main consequence observed under these conditions was a marked enrichment of plasma with vitamin E, which was also significantly and selec tively noted in HDLs (no changes in LDL vitamin E content), perhaps related to a specific storage capacity for vitamin E in HDLs of haemodialysis pati ents. The beta -carotene content of plasma, LDLs and HDLs was also higher a fter use of vitamin E-coated membranes than after use of high-flux biocompa tible membranes. HDL copper oxidizability was reduced (as shown by an incre ased lag time) before dialysis after use of CL-EE membranes compared to con ventional membranes, whereas LDL oxidizability remained unchanged. Conclusion. A 3-month use of vitamin E-coated membranes resulted in a signi ficant increase in plasma and HDL vitamin E content, associated with a lowe r oxidizability of HDLs, which could be beneficial for haemodialysis patien ts.