Establishment and Evaluation of an In Vitro Human-Based Advanced Model of Pulmonary Fibrosis.

Pulmonary fibrosis is characterized by irreversible destruction of alveolar structure and excessive deposition of extracellular matrix. Although animal models have been widely used in pulmonary fibrosis research, none of the currently available models fully recapitulate the progressive nature of IPF or its defining histological feature, such as fibroblastic foci. Advanced in vitro models, including precision-cut lung slices (PCLS), are often considered the most physiologically relevant pulmonary test system and have been successfully employed for drug screening. Nevertheless, the inability to differentiate the degree of fibrosis in the IPF lung has resulted in blinding and uncertainty in the PCLS obtained. Previous research demonstrated that fibroblast activation protein (FAP) could evaluate the pro-fibrotic activity of ILD, potentially contributing to early diagnosis and the selection of appropriate therapeutic windows. In this study, 600 µm PCLS will be obtained from healthy donors and IPF patients using a shock slicer and evaluated using molecular probes targeting FAP to determine the degree of fibroblast activity based on fluorescent signal intensity. This approach provides an advanced in vitro model and evaluation technique for pulmonary fibrosis research, enhancing the ability to study disease mechanisms and assess therapeutic interventions.