#4454 PERITONEAL DIALYSIS (PD) EFFLUENT DERIVED EXTACELLULAR VESICLES TO ESTABLISH PD-INDUCED PERITONEAL ALTERATIONS

Abstract Background and Aims Peritoneal dialysis (PD) is a life-saving kidney replacement treatment in patients with end-stage disease (ESKD). Yet, long-term exposure of the peritoneal membrane to glucose its degradation products results fibrosis loss function. At present, detection early specific injury challenging. With evolving therapies, biomarkers assess vitality response interventions mitigating PD-treated mandatory. Extracellular vesicles (EVs) are nano-sized structures containing proteins, micro-RNAs (miRNAs) lipids reflecting their cells origin have role intercellular communication. EVs been widely investigated as potential easy-accessible stable biomarkers, particularly inflammatory conditions. Here, we describe clinically applicable robust technique isolate analyze molecular cargo effluent (PDE)-derived (PDE-EVs). Method PDE was collected from adult treated PD, excluding those recent peritonitis (<6 weeks). First, cell-free obtained by centrifugation. As filtration concentration quality control step cel-miRNA39 packed EV-sized liposomes added PDE. PDE-EVs were isolated subsequent size-exclusion chromatography (SEC). We used Western blot EV-markers Flotilin 1, 70 kilodalton heat shock protein (HSP70), Syntenin confirm presence SEC-fractions. Calnexin marker other membranes an indication purity. To robustness steps, exogenous quantified qPCR. Endogenous miRNA21 -10b check if contain adequate amounts small RNA for future analyses. Results 13 (mean age 64,7 years (standard deviation 20,1 years); 62% female; 46% APD; median PD-vintage 18 months (range 7–33 months)). Presence confirmed (Fig. 1). A weak staining observed 1-hour dwell time. There no difference between 4-hour dwells, 24-hour collection or 10-hour dwell. No seen. Ct-values endogenous -10b, qPCR, showed signals all types 2). relevant differences seen samples different duration concentrations instilled PD-fluids. Conclusion present reproducible method molecularly characterize PDE-derived EVs. Further characterization may serve novel means monitor changes over time during PD biomarker risk stratification terms systemic (cardiovascular) sequelae PD-induced responses. This would fill two important caveats contemporary PD-management.