PolyCore, a bimodal peritoneal dialysis solution based on xylitol, L-carnitine, and icodextrin: In vitro evidence of the peritoneal membrane protection, rationale, and design of the phase II pilot study EXCITE

Background: Glucose exposure in peritoneal dialysis contributes to local peritoneal membrane injury and systemic metabolic complications. The osmo-metabolic approach seeks to reduce glucose burden by using alternative osmotic agents such as xylitol and L-carnitine. PolyCore is a novel glucose-free bimodal peritoneal dialysis solution combining icodextrin (4%), xylitol (1.5%), and L-carnitine (0.02%), designed to provide sustained ultrafiltration while improving biocompatibility. Methods: Human peritoneal mesothelial cells were exposed to PolyCore, icodextrin 7.5% solution, or a control medium. Cell viability, transepithelial electrical resistance, fibrosis-related gene expression, and α-SMA (alpha-smooth muscle actin) protein expression were assessed. In parallel, the EXCITE study was designed as a phase II, single-arm, prospective pilot trial evaluating PolyCore in 28 adults with end-stage kidney disease receiving incremental peritoneal dialysis. Results: PolyCore preserved mesothelial cell viability and barrier integrity, with transepithelial resistance values comparable to control and significantly higher than icodextrin 7.5%. Compared with icodextrin 7.5%, PolyCore showed a more favorable expression profile of mesothelial-to-mesenchymal transition markers, with lower α-SMA and vimentin and preserved E-cadherin. The EXCITE study will assess safety and preliminary efficacy, including dialysis adequacy, ultrafiltration, solute removal, metabolic parameters, and patient-reported outcomes. Conclusions: PolyCore showed favorable in vitro biocompatibility compared with standard icodextrin 7.5% and may represent a glucose-free bimodal strategy for peritoneal dialysis. EXCITE will provide first clinical assessment on the safety and preliminary efficacy of PolyCore.