Proteomic analysis of peritoneal fluid of patients treated by peritoneal dialysis: effect of glucose concentration

Background. Depending on both membrane composition and solute transport rate across the membrane, protein composition of the dialysate of patients receiving peritoneal dialysis (PD) has recently become of great interest. Unfortunately, thus far few studies have focused on dialysate characterization, and further investigations are required to better understand the biological mechanisms influencing PD efficiency. Methods. Different classical proteomic approaches were combined with advanced mass spectrometric (MS) techniques to analyse peritoneal fluid (PF) protein composition of adult patients receiving PD. Characterization was performed by using 1D gel electrophoresis combined with nano-RP-HPLC-ESI-MS/MS and shotgun proteomics, while comparative analyses were performed coupling 2D gel electrophoresis with MALDI-TOF MS. Results. The study allowed the identification of 151 different proteins from PF, which are mainly of plasmatic origin. Comparison of PD effluents characterized by different glucose concentrations demonstrated four proteins (apolipoprotein A-IV, fibrinogen beta chain, transthyretin and alpha-1-antitrypsin) to be under-expressed in the highest osmolar solution having 4.25% compared to others having 1.5% and 2.5% glucose. All of them were found to be involved in the inflammatory processes. Conclusions. This study provides a possible platform for future diagnostic and therapeutic applications in the field of PD and allowed the identification of potential targets to be used in preventing inflammatory processes induced by the exposure to dialysis solutions.