HIF1A and pulmonary fibrosis: Moreover, hypoxia is present in pulmonary fibrosis and its role in modulating alveolar macrophage phenotype was examined by Philip et al. Using the mouse bleomycin-induced model of pulmonary fibrosis and IPF lung samples, they determined that inhibition of HIF1α resulted in a reduction in pulmonary fibrosis, along with the diminished expression of A2BAR in alternatively activated macrophages (AAMs).