Clinical significance of protein adsorbable membranes--long-term clinical effects and analysis using a proteomic technique.

Polymethylmethacrylate (PMMA) membranes were first developed in Japan in 1977. Over its 30-year history, use of PMMA has given rise to a new generation of dialysers and continues to evolve. In long-term observation of patients treated with PMMA membranes (BK series), it has been found that serum beta2-microglobulin is maintained at a significantly lower level than in haemodialysis (HD) patients undergoing treatment with conventional cellulosic membranes. Regarding long-term side effects, radiolucent bone cysts (RBC) and carpal tunnel syndrome (CTS) have developed in relatively few patients undergoing HD with PMMA membranes. The profiles of various proteins in the blood of HD patients differ from those in normal subjects. PMMA membranes remove a wide variety of solutes not only via permeation, but also adsorption. Numerous reports have noted that pruritus can be ameliorated with the use of slightly anionic PMMA membranes (BG series). We have been performing proteomic analysis of plasma from HD patients with pruritus. We have confirmed that slightly anionic PMMA membranes can adsorb components with a molecular weight of 160,000 Da, which have stimulatory effect on mast cells from pruritus.