Proteomic analysis of proteins adsorbed by resin cartridge filter during hemodiafitration with online endogenous reinfusion.

BACKGROUND-AIM Background: Lupus nephritis (LN) is kidney inflammation caused by systemic lupus erythematous (SLE), that lead to end stage renal disease and consequently to dialytic therapy. Inflammation mediators over-expression play a key role in disease initiation and progression. Immuno-complexes and/or autoantibodies deposition in the kidney induce cytokines production in renal resident cells, which may further amplify inflammatory processes. Hemodiafiltration with Endogenous Reinfusion (HFR) dialysis treatment with super high flux membrane Synclear 02 (SUPRA) is a dialytic method, which combines the diffusion and convection processes with adsorption by a resin cartridge filter. Proteomic approach was applied for protein separation and identification in order to evaluate the quality of proteins retained by resin bed during dialytic treatment. METHODS Methods: Plasma and ultrafiltrate (UF) samples of three patients with LN, treated with SUPRA HFR (Bellco, Italy), were collected at 15 and 235 min of two different dialytic sessions. The utilized cartridges, containing styrenic resin, were opened and the proteins kept by the resin were eluted. Gel electrophoresis was used to separate protein content before protein identification by ESI-QTOF-MS (Electrospray Ionization-Quadrupole Time-of-Flight-Mass Spectrometry) analysis RESULTS Results: The comparison of proteomic profiles of plasma, UF and eluted samples demonstrate the removal of several protein species by the resin bed. ESI-QTOF analysis allowed to identify several biomarker of kidney injury, such as: Retinol binding protein 4, Neutrophil gelatinase-associated lipocalin (NGAL), Prostaglandin-H2 D-isomerase, Cystatin- C, Serotransferrin, Alpha-1-acid glycoprotein (A1AG1), Transthyretin and several fragments of Immunoglobulins. Moreover, Beta-2-glycoprotein 1 (APO-H), involved in antiphospholipid syndrome, a disorder that manifests clinically as recurrent venous or arterial thrombosis, was identified. CONCLUSION Conclusions: The proteomic approach was used in this study to evaluate the performance of styrenic resin to retain proteins implicated in the LN pathogenesis and pathophisiology. The treatment with SUPRA-HFR demonstrate to be suitable to reduce inflammatory status, uremic toxin level and antiphospholipid syndrome in LN patients.