ACE2 and acute respiratory distress syndrome: To investigate the mechanisms behind this interaction, a combined acute respiratory distress syndrome and chronic alcohol abuse mouse model was developed by intratracheally instilling the subunit 1 (S1) of SARS-CoV-2 spike protein (S1SP) in K18–human angiotensin-converting enzyme 2 (ACE2) transgenic mice that expressed the human ACE2 receptor for SARS-CoV-2 and were kept on an ethanol diet.