From Uremic Toxins to Hemodialysis Access Failure: IL-8 and MCP-1 Chemokines as a Link Between Endothelial Activation and AV Access Complications.

Arteriovenous (AV) access complications remain a major cause of morbidity in hemodialysis patients, influenced by multiple factors, including endothelial inflammation induced by uremia. In this study, we investigated the mechanisms underlying the upregulation of endothelial chemokines interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) by indolic uremic toxins, as well as their association with AV access complications in hemodialysis patients. In cultured human endothelial cells, IL-8 and MCP-1 were upregulated by indolic uremic toxins through activation of their receptor, the aryl hydrocarbon receptor (AHR), and non-canonical TGF-β pathway involving TAK1/p38 MAPK/AP-1 signaling. In a retrospective observational study of 204 hemodialysis patients, baseline serum IL-8 or MCP-1 were positively correlated with indolic uremic toxins and TGFβ1. Additionally, serum IL-8 ≥ 40.26 pg/mL and serum MCP-1 were independently associated with an increased risk of AV access complications over a 2-year period. In conclusion, we demonstrated that indolic uremic toxins promote endothelial inflammation by inducing IL-8 and MCP-1 expression via AHR activation and non-canonical TGF-β signaling. Clinically, elevated serum IL-8 and MCP-1 were independently associated with an increased risk of AV access complications in hemodialysis patients.