Indeed, analysis of plasma samples (from a healthy subjects), treated ex vivo with recombinant renin, showed an increase of Ang I, Ang II, Ang (1–7) and Ang (1–5), but not Ang (1–9) [115,179,181], further suggesting both the ACE2 specific activity in producing Ang (1–9) and an activation of both arms of the RAS in ARDS patients.