ACE-2 Expression in the Small Airway Epithelia of Smokers and COPD Patients: Implications for COVID-19

Janice M Leung; Chen Xi Yang; Anthony Tam; Tawimas Shaipanich; Tillie L Hackett; Gurpreet K Singhera; Delbert R Dorscheid; Don D Sin

These findings were observed in 3 different cohorts, indicating their generalizability and robustness. ACE-2 is a type I transmembrane metallocarboxypeptidase with homology to angiotensin converting enzyme (ACE). In contrast to ACE, which converts angiotensin I to the active vasoconstrictor, angiotensin II, ACE-2 breaks down angiotensin II to its metabolites including angiotensin-(1-9) and angiotensin-(1-7), which are potent vasodilators, and thus may be a negative regulator of the renin-angiotensin system [16] . ACE-2 is expressed in a variety of different tissues including both the upper and lower respiratory tract, myocardium and the gastrointestinal mucosa [17] . Although its role in human health and disease has not been fully elucidated, it appears to have an . CC-BY-NC-ND 4.0 International license It is made available under a author/funder, who has granted medRxiv a license to display the preprint in perpetuity.