Background: Idiopathic pulmonary fibrosis(IPF) is a chronic, progressive lung disease that leads to respiratory failure and death due to irreversible scarring of the distal lung. While historically considered a chronic inflammatory disorder, the aberrant function of the alveolar epithelium is now recognized to play a central role in IPF pathophysiology. Alveolar type 2 cells(AT2) are known for the regenerative capacity in the alveoli.

Aims: This study aimed to investigate the regenerative capacity of AT2 using IPF-derived alveolar organoids and to examine the effects of disease progression on this capacity.

Methods: 3 early-stage IPF tissues were obtained by surgical lung biopsy, 3 advanced-stage by lung transplantation. HTII-280+ cells were isolated from CD31-CD45-EpCAM+ cells in the distal lungs of IPF patients using fluorescence-activated cell sorting(FACS) and resuspended in 48-well plates to establish IPF-derived alveolar organoids. Cryo-section slides were prepared and validated using immunostaining to confirm the presence of AT2 cells.

Results: FACS sorting yielded approximately 1% AT2 cells of the total cells in IPF tissue. Immunostaining of the alveolar organoids revealed the presence of KRT5+ cells, indicating the presence of basal cells and providing an explanation for the conversion of AT2 cells to basal cells. On day 30, the colony forming efficiency in the advanced stage of IPF-derived organoids was lower than in the early stage.

Conclusions: These findings suggest that disease progression in IPF may lead to a decreased regenerative capacity of AT2 cells, resulting in a lower efficiency in the formation of IPF-derived alveolar organoids.