Proteomic analysis to improve adequacy of hemo- and peritoneal dialysis: Removal of small and high molecular weight proteins with high- and low-flux filters or a peritoneal membrane

The reduction of morbidity and mortality in patients undergoing hemo- or peritoneal dialysis is strongly related to an efficient and selective clearance of uremic toxins. We used proteomics methods to analyze and further characterize the dialytic removal of still undefined middle and high molecular weigh proteins as a basis for further improvement of dialysis assessment. Dialysates from 26 hemodialysis patients treated with different types of low- (F6HPS?) and high-flux (FX80?, APS650?, FX60?) filters as well as peritoneal fluids from 10 continuous ambulatory peritoneal dialysis (CAPD) patients were analyzed by SELDI-TOF and 2-DE. The protein patterns showed selective differences in the proteins cleared depending on the dialysis method used and the filter membrane. While SELDI analyses of dialysates from the F6HPS revealed almost no protein clearance, high-flux filters and CAPD dialysates showed protein release of different molecular weight ranges. Furthermore, 2-DE and MS analysis identified 48 different proteins from the dialysate of high-flux filters and 21 from peritoneal dialysis fluids. In F6HPS dialysates, however, only few proteins could be identified.