Nintedanib mediates effective modulation of relevant pro-fibrotic biomarkers ex vivo

Rationale: Pulmonary fibrosis (PF) is a severe lung disease causing irreversible dysfunction of the organ. However, the pathomechanism of PF is not yet fully understood. Precision-cut lung slices (PCLS) provide a physiologically relevant model that circumvents drawbacks of simple single-cell cultures (e.g. lack of polarized phenotype). Nintedanib is a tyrosine kinase inhibitor approved for the treatment of idiopathic pulmonary fibrosis. Aim: To use PCLS as novel experimental approach to identify and modulate biomarkers of PF ex vivo. Methods: PCLS were prepared from lungs of bleomycin (BLM) or NaCl-treated rats, or lung tissue from patients with PF (huPF-PCLS). Cytokines and extracellular matrix (ECM) remodelling were measured in supernatant and expression profiles were assessed in lung tissue. Results: Important pro-fibrotic genes are upregulated in lungs from BLM-treated rats compared to controls. PCLS prepared from these animals retain the pro-fibrotic expression pattern in culture for 2 - 5 days. ECM genes, collagen1a1 (Col1a1) or fibronectin1 (Fn1) were found up-regulated 5 - 6-fold compared to controls. Nintedanib treatment inhibits the expression of this pro-fibrotic pattern. Increased expression levels of Fn-1, pro-Col1a1 were also detected in supernatants of huPF-PCLS compared to PCLS from non-PF tissue after two days of culture. IL-6 secretion of huPF-PCLS was reduced 2-fold by nintedanib treatment ex vivo. Conclusion: Relevant pro-fibrotic biomarker are expressed in PCLS from BLM treated rats and huPF-PCLS. In both approaches, the defined pattern resembles important mediators of tissue fibrosis with high translational relevance. Nintedanib treatment efficiently inhibited these mediators.