Studies have reported that inhibition of DPP4 by pharmacological inhibitors alleviated fibrotic responses, such as in bleomycin-induced dermal and pulmonary fibrosis (Soare et al., 2020), CCl4-induced liver fibrosis (Kaji et al., 2014; Wang et al., 2017), and a high-salt-diet-induced cardiac failure and fibrosis (Esposito et al., 2017). This evidence concerns the gene DPP4 and pulmonary fibrosis.