The principal mechanisms of blood depuration by hemodialysis are diffusion, convection and adsorption. Hemodialysis may be performed using low-flux (LF) membranes which remove only small molecules, or high-flux (HF) membranes with remove also bigger molecules.
Aim of the this study was to assess, by means of proteomic techniques, the relevance of convection and adsorption of proteins with different membranes.
Seventeen patients treated with LF polysulphone and with HF membranes (Triacetate; Helixone; Polyamide).
Proteomic analysis. 30 min after the beginning of the dialysis a sample of ultrafiltrate fluid was analyzed by means of biochemical and proteomic techniques. At the end of the dialysis we assessed the adsorption of proteins on the different dialytic membranes. The proteins in the ultrafiltrates and those eluted from the membranes were analyzed through SDS PAGE, 2DE, and MALDI-TOF.
Biochemical analysis. A very high removal of small molecules was demonstrated, which was similar with all the membranes. The removal of B2M was high with HF membranes and insignificant with LF membrane. The removal of bigger molecules (myoglobin and BNP) was higher with triacetate than with the other HF membranes.
Proteomic analysis. No convection of small proteins (LMWP) in the ultrafiltrate fluid was found through LF polysulfone. Polyamid and helixone allowed the convection of LMWP. In the ultrafiltrate of triacetate a higher amount of different LMWP was demonstrated.
Proteins with different MW were found in the eluates from the different membranes. In particular, albumin and LMWP were demonstrated on the inner part and inside the triacetate membrane. Much more than with the other membranes.
Proteomic technology allows a better understanding of mechanisms of blood depuration of the different membranes.