ACE2 and infection: A previous study indicated that ACE2 is a pivotal regulator of the renin-angiotensin-aldosterone system (RAAS) and influences inflammatory reactions and immune functions.[126] It was found that ACE2 messenger RNA is highly expressed and the encoded protein heterodimers with the neutral amino acid transporter broad neutral amino acid transporter 1 (B0AT1) (SLC6A19) or the imino acid transporter sodium-dependent imino transporter 1 (SIT1) (SLC6A20) in the GI tract.[91,127] They can provide potential binding sites for SARS-CoV-2 spike glycoproteins and subsequent infections.