Studio della fisiopatologia delle malattie renali e dell’uremia: analisi proteomica e determinazione nel plasma e nelle urine di proteine di piccolo peso molecolare ed altri indicatori di funzione renale.

Hemodialysis membranes At time 30 min after the beginning of the dialysis session a sample of ultrafiltrate fluid was drawn and analyzed by means of biochemical and proteomic techniques. No convection of LMWP was found with polysulfone membrane. Polyamide and Helixone membrane allowed the convection of ß2-microglobulin alone. In the UF of the triacetate membrane a higher amount of different LMWP was demonstrated. To study the local processes that occur on dialysis membranes we analyzed the proteins adsorbed to the different dialytic membranes (F8, FX80,FX1000,N190H and Poly 210H) after a standard dialysis session of 4 hours. Each dialyzer was emptied and directly filled with 80-100 ml of 3mM EDTA (EDTA/PBS, pH=7.4) thereafter it was re-circulated with a peristaltic pump (flow rate: 400ml/min, time 30 min). Then each dialyser was loaded with 80ml of 40% acetic acid and re-circulated again (flow rate: 400ml/min, time 30 min), and the resulting eluate were collected, centrifuged, desalted, and concentrated. The same method has been used, pumping the EDTA and Acetic acid solutions towards the membrane from outer to inner surface, to remove also proteins that adsorbed into the layer of the membrane. The proteins present in the eluates and in the ultrafiltrates were separated through 2DE- SDS PAGE. Very different concentration of proteins, with different MW, were found in the eluates from the different membranes. Furthermore the mass spectrometric analysis of isolated spots, has allowed us to identify the proteic pattern of the eluates. This approach may be used to have a more complete picture about biocompatibility of the membranes.