#3230 CHARACTERISTICS OF PROTEIN LOSS WITH MEDIUM CUT-OFF MEMBRANES COMPARED TO HIGH FLUX MEMBRANES

Abstract Background and Aims Medium cut-off membranes (MCO) have been introduced with the claim that larger pores enhance removal of middle-sized uremic toxins. To date, no adequately powered randomized controlled trial has demonstrated this membrane characteristic translates into improved mortality. A well-described consequence pore sizes is a higher dialytic albumin loss [1]. In addition, other proteins could also be lost MCO, including ones are beneficial or even essential, e.g., to patients’ nutritional status. better understand spectrum cleared we set up an ex vivo HD simulation system compared protein characteristics between MCO high-flux (HF) dialyzers. Method Over course hour, single reservoir 2.5 liters EDTA human plasma was ultrafiltered using two Fresenius 2008T machines. One machine served dialyzer (Theranova 400), HF (Fresenius Optiflux F180NR). Ultrafiltrate (UF) returned (Figure 1A). Blood flow 400ml/min, dialysate zero, ultrafiltration rate 13ml/min. UF samples were taken at ∼10 min intervals. Upon experiment completion, residual filtrate collected from compartment. Samples stored −80°C until analysis Bradford assay, silver-stained SDS-Page, Olink Proteomics (Watertown, MA). Selected underwent 3K MWCO concentration. Results Figure 1B shows concentration several time points. Total (in mg) during one-hour 18 239 in UF, 10 359 filtrate, respectively. SDS-PAGE gel revealed contained less amount than when equal volumes loaded 1C, lane 3 vs 2, 6 5). Smaller more abundant amounts (lane 4 7 both >100 kD 1). Finally, (collected 20 60 min) concentrated ∼1mg/ml analyzed targeted biomarker Olink® Target 96 Organ Damage panel. Ten 92 panel above limit detection (LOD; Table The MCO-to-HF ratio ranged 1.7 13.1. Conclusion Our results show HF. distribution skewed towards lower molecular weights filtrate. All identified Further identification quantification hemodialysis will improve our understanding clinical impact different dialysis membranes.