Fig.2. Mechanism for pulmonary vasoconstriction in COVID-19 pneumonia.
Pathways highlighted green are relatively activated while red highlights represent relative inactivation.
ACE: angiotensin-converting enzyme; ACE 2: angiotensin-converting enzyme 2; AT II:
Angiotensin II; AT I: Angiotensin I; AT1R: Ang II type-1 receptor; AT2R: Ang II type-2
receptor; NOX: nicotinamide adenine dinucleotide phosphate oxidase; LOX-1: Lecithin-
Like oxLDL Receptor-1; ETAR: Endothelin-1A receptor; B2R: B2 receptor; eNOS:
endothelial nitric oxide synthase; SOD: superoxide dismutase; NO: nitric oxide; PLC:
phospholipase C; PKC: protein kinase C; TACE: Tumor necrosis factor alpha converting
enzyme; s-TNF-α: soluble tumor necrosis factor alpha; IL6R1: interleukin 6 receptor;
IL6: interleukin 6; AT 1-7: angiotensin 1-7; PI3K/PKB/Akt: phosphoinositide-3-
kinase–protein kinase B/Akt; AMPK: adenosine monophosphate-activated protein
kinase; miR: microRNA; EC: endothelial cell; VSMC: vascular smooth muscle cell.