ARG1 and pulmonary hypertension: In fact, an upregulation of Arg1 has been found in pulmonary diseases, including chronic obstructive pulmonary disease, pulmonary hypertension, pulmonary fibrosis, tuberculosis, and asthma (North et al, 2009; Henno et al, 2015; Monin et al, 2015; Lucca et al, 2018; Wu et al, 2019).