Introduction
Chronic Kidney Disease (CKD) represents a substantial global health burden, affecting approximately 10% of the adult population. A major contributor to CKD progression is low-grade inflammation, which promotes fibrosis, leading to gradual loss of kidney function. To date, a need remains for reliable and translational human models of inflammation-driven CKD to enhance our understanding of the mechanisms linking inflammation and fibrosis driving CKD pathogenesis.
Aim
Our objective was to establish a novel model of inflammation-driven CKD using human precision-cut kidney slices (PCKS).
Methods
Human PCKS were prepared from macroscopically healthy kidney tissue obtained from tumor nephrectomies. The PCKS were cultured for 24h or 48h with or without Tumor Necrosis Factor α (TNFα) or Lipopolysaccharide (LPS) stimulation. The inflammatory response in the slices was assessed via qPCR by studying the expression of four different pro-inflammatory genes (TNF, IL1B, CCL2, and IL6) and a 42-target cytokine membrane array. Furthermore, the presence of tissue resident macrophages and their activation potential, were investigated using immunofluorescent staining of the macrophage markers: CD68 and CD163, along with ELISA measurements of soluble CD163 (sCD163) – a macrophage activation marker.
Results
Stimulation of the PCKS with TNFα, a key pro-inflammatory mediator, led to a more than 2.5-fold increase in the gene expression of TNF, IL1B, CCL2, and IL6 compared with the 24h and 48h control (n=10, p<0.01 shown by a Wilcoxon signed rank test). In addition, the cytokine membrane array revealed that 17 out of the 42 targets could be detected in the culture media from the slices. The levels of these cytokines and chemokines varied depending on the incubation time and presence of TNFα stimulation.
Moreover, using immunofluorescence we observed clear staining of CD68+ and CD163+ cells in the tissue, indicating the presence of tissue resident macrophages in the PCKS model. As a measure for macrophage activation, we detected a 1.5-fold increase in the amount of sCD163 in the culture media after 24h of stimulation with LPS, known to mediate CD163 shedding and macrophage activation, compared to the 24h control (n=4, p<0.05 shown by a Mann-Whitney test). There was no significant change in sCD163 levels after TNFα stimulation.
Conclusion
In conclusion, this study presents a novel human model for investigating inflammation-driven CKD, paving the way for an improved understanding of the complex CKD pathophysiology. Furthermore, the PCKS model holds potential as a future platform for the screening of anti-inflammatory CKD therapeutics.