LNCARGI and chronic obstructive pulmonary disease: It is, however, not clear, whether arginase and which isoform of the enzyme is involved in pulmonary aging that is associated with inflammation (inflammaging) and fibrosis, although both isoforms of arginase Arg‐I and Arg‐II have been reported to play a role in the pathogenesis of pulmonary diseases, including asthma, cystic fibrosis, and chronic obstructive pulmonary disease (COPD) (Jaecklin et al., 2014; Maarsingh et al., 2008; Pera et al., 2014).