Passage of endotoxin, beta-glucan and peptidoglycan in tap water through high flux membrane dialyzer

We evaluated the passage of endotoxin (ET), beta-glucan (BG), and peptidoglycan (PG) across high flux membrane dialyzers using tap water as a test solution. We tested cellulose tri-acetate (FBF, Nipro), polymethylmethacrylate (BKF, Toray), and polysulfone (PSN, Kawasumi, and APS, Asahi) high-flux membrane (HFM) dialyzers in this study. Conventional regenerated cellulose membrane (RCM) dialyzer served as a control. The experimental design used a recirculating batch system for 120 minutes. Endotoxin-free 0.05% albumin containing distilled water solution was circulated as the blood compartment and tap water was circulated as dialysate compartment. Samples were estimated by endotoxin specific test (ES) for ET, high sensitive test (HS) for ET and BG, and silkworm larvae plasma test (SLP) for BG and PG with Toxinometer MT-358 (Wako) supplied by Wako Pure Chemical industries Ltd. (Osaka). ES activity was high in the dialysate compartment, but not detectable in the blood compartment by all HFM dialyzers and the RCM dialyzer. HS activity was detectable in the blood compartment, but decreased in the dialysate compartment by all HFM dialyzers and the RCM dialyzer. The blood compartment in the RCM dialyzer showed the highest HS activity among PSN, BKF, FBF and APS. SLP activity was high in the blood compartment and dialysate compartment by all HFM dialyzers and the RCM dialyzer. The blood compartment in the RCM dialyzer showed the highest SLP activity among PSN, FBF, APS and BKF. These data showed, that ET did not pass through HFM, but adsorbed to membrane surface of HFM. BG may have passed through the HFM dialyzer. The RCM dialyzer eluted BG derived from cellulose material which might stimulate SLP activity. This study also indicated that tap water was useful for evaluating passage of SLP activating substances across HFM dialyzers.