ACE2 and acute respiratory distress syndrome: The RAS is central to pulmonary vascular tone regulation.64 65 ACE-2 cleaves angiotensin-II (Ang-II) to produce Ang1-7.29 40 47 64 65 These two products have opposing roles with Ang-II imposing vasoconstriction and Ang1-7 imposing vasodilation.29 64 65 Ang-II levels are detectably higher in ALI or ARDS (NCT01597635), thus Ang-II is believed to promote lung injury.