ACE2 and chronic obstructive pulmonary disease: ACE2 expression has similarly been shown to be increased in COPD: by using combined transcriptomic and immunohistochemical analyses, Leung et al recently demonstrated that epithelial ACE2 expression is increased in bronchial brushings/tissue samples from subjects with COPD versus in healthy controls,14 effects that have also been shown previously in cigarette smoke exposure animal models.35