Peritoneal dialysate‐range hypertonic glucose promotes T‐cell IL‐17 production that induces mesothelial inflammation

Abstract

Peritoneal dialysis (PD) employs hypertonic glucose to remove excess water and uremic waste. Peritoneal membrane failure limits its long-term use. T-cell cytokines promote this decline. T-cell differentiation is critically determined by the microenvironment. We here study how PD-range hypertonic glucose regulates T-cell polarization and IL-17 production. In the human peritoneal cavity, CD3⁺ cell numbers increased in PD. Single cell RNA sequencing detected expression of T helper (Th) 17 signature genes RORC and IL23R. In vitro, PD-range glucose stimulated spontaneous and amplified cytokine-induced Th17 polarization. Osmotic controls l-glucose and d-mannose demonstrate that induction of IL-17A is a substance-independent, tonicity dose-dependent process. PD-range glucose upregulated glycolysis and increased the proportion of dysfunctional mitochondria. Blockade of reactive-oxygen species (ROS) prevented IL-17A induction in response to PD-range glucose. Peritoneal mesothelium cultured with IL-17A or IL17F produced pro-inflammatory cytokines IL-6, CCL2, and CX3CL1. In PD patients, peritoneal IL-17A positively correlated with CX3CL1 concentrations. PD-range glucose-stimulated, but neither identically treated Il17a^-/- Il17f^-/- nor T cells cultured with the ROS scavenger N-acetylcysteine enhanced mesothelial CX3CL1 expression. Our data delineate PD-range hypertonic glucose as a novel inducer of Th17 polarization in a mitochondrial-ROS-dependent manner. Modulation of tonicity-mediated effects of PD solutions may improve membrane survival.