18 In vitro investigation of vancomycin-induced kidney injury: development of a 2D cellular model

Introduction Vancomycin is a glycopeptide antibiotic that targets gram-positive bacteria and is the recommended treatment against MRSA infections. However, it is known to cause kidney injury in children. Vancomycin accumulates in proximal tubule cells but relatively little is known regarding the mechanism of this. We conducted a multiparameter assessment of vancomycin toxicity in a novel human renal cell line, Conditionally immortalised proximal tubule epithelial cells (ciPTECs), to determine if these cells recapitulate vancomycin-induced kidney injury (VIKI) in vitro. Methods Three ciPTEC lines were used (parent ciPTEC, and ciPTECs with upregulated expression of organic anion transporters 1 (ciPTEC OAT1) or 3 (ciPTEC OAT3), to assess the respective involvement of these transporters in vancomycin accumulation. ciPTECs were cultured at 33°c and seeded in 96-well plates at 1x104 cells/well. Vancomycin stocks were prepared in distilled water and administered between 1mM and 10mM for 24hr incubations before cell viability (ATP) and cell cytotoxicity (LDH) assays were performed. Results ATP data showed a dose-dependent increase in vancomycin toxicity with 17% cell viability observed at10mM. (EC50=5.6mM) Membrane permeabilization was only observed at 10mM (60% LDH retention), with no change observed at lower concentrations administered. There was no difference in vancomycin toxicity observed between each cell type. Conclusions Our results suggest that ciPTECs recapitulate the nephrotoxicity induced by vancomycin and indicates that OATs are not involved in vancomycin uptake. Here, we established a proof of concept for the use of ciPTECs as a 2D cellular model for VIKI as toxicity was observed after vancomycin administration.