Nintedanib attenuates peritoneal fibrosis by inhibiting mesothelial‐to‐mesenchymal transition, inflammation and angiogenesis

Nintedanib, an Food and Drug Administration (FDA) approved multiple tyrosine kinase inhibitor, exhibits an anti‐fibrotic effect in lung and kidneys. Its effect on peritoneal fibrosis remains unexplored. In this study, we found that nintedanib administration lessened chlorhexidine gluconate (CG)‐induced peritoneal fibrosis and reduced collagen I and fibronectin expression. This coincided with suppressed phosphorylation of platelet‐derived growth factor receptor, fibroblast growth factor receptors, vascular endothelial growth factor receptor and Src family kinase. Mechanistically, nintedanib inhibited injury‐induced mesothelial‐to‐mesenchymal transition (MMT), as demonstrated by decreased expression of α‐smooth muscle antigen and vimentin and preserved expression of E‐cadherin in the CG‐injured peritoneum and cultured human peritoneal mesothelial cells exposed to transforming growth factor‐β1. Nintedanib also suppressed expression of Snail and Twist, two transcription factors associated with MMT in vivo and in vitro. Moreover, nintedanib treatment inhibited expression of several cytokines/chemokines, including tumour necrosis factor‐α, interleukin‐1β and interleukin‐6, monocyte chemoattractant protein‐1 and prevented infiltration of macrophages to the injured peritoneum. Finally, nintedanib reduced CG‐induced peritoneal vascularization. These data suggest that nintedanib may attenuate peritoneal fibrosis by inhibiting MMT, inflammation, and angiogenesis and have therapeutic potential for the prevention and treatment of peritoneal fibrosis in patients on peritoneal dialysis.