Pulmonary fibrosis (PF) is a progressive lung disease characterised by excessive extracellular matrix (ECM) deposition and destruction of lung architecture. Our study investigates the effects of pharmacological treatments on ECM-associated proteins in human precision-cut lung slices (PCLS). We established a microphysiological system (MPS) for extended PCLS culture to study disease characteristics and support anti-fibrotic drugs development.

Fibrotic explants or healthy lung sections were prepared into PCLS and cultured ± nintedanib/pirfenidone in 24-well plates or MPS.

After 24 hours in culture, 215 ECM-associated genes were differentially expressed in fibrotic vs. non-fibrotic PCLS, with 140 up-regulated and 75 down-regulated. At protein level, for example, MMP-9 and -7, procollagen 1a1 and TGF-? were significantly upregulated in fibrotic PCLS supernatants. Treatment for 48 hours of fibrotic PCLS with pirfenidone and/or nintedanib significantly downregulated these proteins.

In MPS cultivation, median metabolic activity measured by the WST-1 assay was 1.6-fold higher after 14 days of cultivation compared to standard cultivation. The fibrotic phenotype and anti-fibrotic treatment efficacy were also maintained in MPS-cultured PCLS.

We show here that nintedanib/pirfenidone downregulates ECM-associated proteins ex vivo. In addition, the initial results from MPS show great potential for expanded and refined cultivation, e.g. to improve histological analysis of ECM remodelling or disease progression in long-term culture enabeling/providing a valuable endpoint for future preclinical studies.