Effect of Vitamin E-Modified Regenerative Cellulose Membrane on Neutrophil Superoxide Anion Radical Production and Lipid Peroxidation

Evaluation of solute penetration across the polysulfone membrane with vitamin E coating

Vitamin E (vit E) is coated on polysulfone (PS) dialysis membrane for antioxidative purpose. The membrane, however, has not yet been evaluated from the mass transfer point of view. We investigated this PS membrane with and without vit E coating in vitro ultrafiltration experiments to identify whether or not the coating influences the mass transfer. Dialyzers that included PS membrane with and without vit E coating were investigated. Aqueous test solution of various solutes including vitamin B12 (VB12 , MW1355), chymotrypsin (chymo, MW25000), and albumin (alb, MW66000) was prepared, and normal ultrafiltration experiments were performed at 310 K. Reverse ultrafiltration experiments in which test solution was filtered from outside to inside the hollow fiber were also performed. Sieving coefficients (SC) were computed for evaluation. SC for VB12 was the same regardless of vit E coating; however, chymo was 0.82 ± 0.01 and 0.86 ± 0.01, respectively, for the membrane with and without vit E. Thus, it would be understood that vit E coating reduces the pore size of the membrane, resulting the reduced transport of larger solutes. Like other PS membrane, SC for alb was decreased over time regardless of vit E coating. More importantly, although the steady-state SC for alb was almost identical in two membranes, PS without vit E showed much greater decrease for the first 2 h, while that with vit E showed very little decrease over time, which suggested the reduced fouling effect due to vit E coating. All the SC values found in reverse ultrafiltration were higher than those found in normal ultrafiltration; moreover, the degree of increase with chymo was approximately 5%, whereas that with alb was approximately 430%, which may be explained by a new model in which wedge effect is taken into consideration for the membrane transport. Vit E coating not only has antioxidative effect but also reduces the fouling that is usually caused by various proteins.

Development of vitamin E-modified polysulfone membrane dialyzers

Oxygen radicals have recently been attracting close attention because of their involvement in tissue damage and their close relationship to various clinical conditions. It has been suggested that hemodialysis increases oxidative stress, triggering the development of complications such as atherosclerosis and dialysis-related amyloidosis. We recently developed a dialyzer containing a highly functional polysulfone membrane on which vitamin E had been bonded (PS-ViE). The present study was undertaken to evaluate the biocompatibility of this membrane and to conduct other experiments on the membrane in vitro. Human blood was dialyzed with minidialyzers (300-600 cm(2) membrane area) made of PS-ViE, cellulose, or untreated polusulfone (PS), and the effects of the dialyzers on complements (C3a, C4a, and C5a), cytokines (IL-1beta and IL-8), and granulocyte elastase as well as their anti-oxidative activity were investigated (n = 6). The effect of PS-ViE on complement activation and its effects on cytokines were comparable to those of PS membrane, whereas granulocyte elastase following dialysis with the PS-ViE membrane tended to be lower than that seen with PS membrane. The effects of PS-ViE-induced methemoglobin, lipid peroxide, and oxygen radicals were significantly less than those of PS membrane, indicating the antioxidative activity of PS-ViE. Vitamin E-modified polysulfone membrane dialyzers were found to have favorable effects on the immune system and to express antithrombotic and antioxidative effects.

Vitamin E-coated membrane dialyzer and beta2-microglobulin removal

This study was designed to test the removal of beta2-microglobulin (beta2M) in a vitamin E-modified membrane. We investigated in vivo the dialyzer (Excebrane, series EE, 1.8 m2) with respect to hydraulic permeability (Kuf), maximum ultrafiltration rate (UF max), sieving coefficient (Sc), and solute clearances in hemodialysis (HD) and in soft hemodiafiltration (HDF). Kuf was 18.4 ml/h/mmHg, UF max was 75 ml/min, and Sc for beta2M was 0.45. Clearance values at 400 ml/min of Qb in HD were 258 ml/min for urea, 201 ml/min for creatinine, and 135 ml/min for phosphate. In soft HDF, clearances were slightly higher. beta2M clearance was 26 ml/min in HD and 43 ml/min in soft HDF. In conclusion, Excebrane (series EE) procures a soft HDF with an amount of substitution fluid in post dilution mode of over 60 ml/min. Remarkable small solute clearances were obtained when the blood flow was raised to 400 ml/min. A significant reduction of beta2M is demonstrated by HDF.

Vitamin E-bonded hemodialyzer improves neutrophil function and oxidative stress in patients with end-stage renal failure

We evaluated the biocompatibility of a newly developed vitamin E hemodialyzer (CL-EE; Terumo Co Ltd, Tokyo, Japan) by neutrophil function and oxidant stress in patients with end-stage renal failure in a randomized crossover study. Ten patients underwent hemodialysis using either the CL-EE or a control dialyzer membrane identical to the CL-EE except for vitamin E binding for 12 weeks in a crossover fashion after a 1-month washout period with hemophane membranes. White blood cell counts, serum oxidized low-density lipoprotein (Ox-LDL) levels, and malondialdehyde (MDA) levels during hemodialysis sessions were measured at the initiation and end of the CL-EE and control trials. Superoxide anion production by neutrophils just before and 4 hours after starting the session also was measured. Leukocytopenia at 1 hour after starting the session was detected to a similar extent in both membranes. However, the degree of reduction was less in the CL-EE trial after repeated use. Superoxide anion production by neutrophils just before a hemodialysis session was reduced after repeated use of the CL-EE membrane. Serum Ox-LDL levels increased, whereas serum MDA levels decreased during sessions to a similar extent in both trials. However, these parameters were significantly lower in the CL-EE trial after repeated use. Serum LDL concentrations significantly decreased with repeated use of the CL-EE membrane. These data suggest that repeated use of the CL-EE membrane for 3 months improves neutrophil function, oxidant stress, and LDL concentrations in patients with renal failure. This membrane may be useful to reduce the incidence of cardiovascular events in patients with renal failure.