Severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1) 1 and the novel SARS-CoV-2 coronaviruses enter host cells via angiotensin-converting enzyme 2 (ACE2) receptors. ACE2 receptors are highly expressed in lung alveolar epithelial cells, enterocytes of the small intestine, and arterial and venous endothelium. Previous studies have associated high levels of plasma ACE2 with an increased risk of severe illness from SARS-CoV-2 infection, progressing to coronavirus disease 2019 (COVID-19).
