Precision-Cut Human Kidney Slices as a Model to Elucidate the Pathogenesis of Renal Fibrosis

Background: Renal fibrosis is a major problem in chronic kidney disease and chronic renal transplant failure. Unraveling the mechanisms underlying the initiation and progression of renal fibrosis is of key importance to identify new therapeutic targets. However, suitable human ex vivo models for renal fibrosis are lacking. Here, we explored precision-cut human kidney slices (PCKS) as a model for human renal disease. Methods: PCKS were prepared from human cortical kidney tissue obtained from tumor-nephrectomies and cultured up to 96h. Morphology, cell viability (ATP levels, LDH leakage) and metabolic functionality (UDP-glucuronosyltransferase and transporter activity) were determined to assess PCKS integrity. Furthermore, inflammation- and fibrosis-related gene expression was characterized. To validate the model, renal fibrogenesis was induced using transforming-growth factor b1 (TGF-b1). Results: Preparation of PCKS induced an inflammatory tissue response, while long- term incubation (96h) induced fibrogenesis as seen by increased expression of collagen type 1a1 (COL1A1) and fibronectin (FN1). Importantly, PCKS remained functional for more than 48h as evidenced by active glucuronidation and phenolsulfonphthalein uptake. Moreover, treatment with TGF-b1 augmented fibrosis, as illustrated by at least 1.8-fold increase of multiple fibrosis markers including COL1A1, FN1, plasminogen activator inhibitor-1 and α-smooth muscle actin. Conclusions: After extensive characterization, PCKS appear to be an excellent model to investigate renal pathology e.g. renal fibrosis. Moreover, the human origin of PCKS makes this ex vivo model very suitable for translational research