ACE2 and pulmonary fibrosis: Reports show that the ACE2/Ang(1–7)/Mas receptor pathway antagonizes the ACE/AngII/AT1R axis and that the ACE2/Ang-(1–7)/Mas axis protects against pulmonary fibrosis by inhibiting the MAPK/NF-κB pathway [23, 34]; AngII upregulates the expression of the pro-fibrotic cytokine TGF-β1, which is involved in both the fibroblast to myofibroblast conversion and collagen accumulation [35], and ACE2 breaks down AngII into Ang-(1–7) and inhibits fibrosis development [36].