Role of mitochondrial respiratory chain complex III in high glucose peritoneal dialysate-induced hyperpermeability of HPMCs

Background: High-glucose-based peritoneal dialysis solution (PDS) is considered to be one of the primary causes for the increase of ionic permeability in peritoneum as detected by transmesothelial electrical resistance (TER) measurements and claudin-1 expression. However, the mechanism is not clear. The aim of this study is to test the hypothesis that high-glucose PDS induces hyperpermeability in human peritoneal mesothelial cell (HPMC) monolayer by mitochondrial respiratory chain complex III pathway. Methods: HPMCs were cultured in a 1 : 1 mix of Dulbecco's modified Eagle's medium (DMEM) and PDS containing 1.5% and 4.25% glucose for 24 h. A 1 : 1 mixture of 160 mg/L glutathione and 4.25% glucose PDS was also added as an antioxidant group. TER measurement and immunostaining and western blot analysis of claudin-1 expression were examined for detection of permeability damage in HPMCs. MitoSOX (TM) Red staining and respiratory chain complexes' activities were determined for detection of mitochondrial reactive oxygen species (ROS) production and mitochondrial complexes' activities. Results: TER decreased in a time-and concentration-dependent manner after culture with high-glucose PDS for 24 h. Claudin-1 was also downregulated. Complex III activity was inhibited accompanied by increasing mitochondrial ROS generation. These changes were partially prevented by glutathione. Conclusion: These findings demonstrate that mitochondrial respiratory complex III pathway has crucial importance in maintaining permeability of HPMCs, which might reveal a valuable target for novel therapies to fight hyperpermeability of peritoneum during the prolonged PD treatment.