SERPINE1 and COVID-19: Since this discovery,7 the importance of endothelial activation and dysfunction in COVID-19 has been intensively pursued.8,18,23,26 More recently, increased markers of vascular inflammation,27 oxidative stress,28 EndoMT,29 coagulation (D-dimer and plasminogen activator inhibitor-1),15,30 immunothrombosis,31 angiogenesis,15 altered endothelial cell metabolism (glycolysis),32 glycocalyx disruption33 have been observed in patients with COVID-19 or SARS-CoV-2 spike protein treated endothelial cells (reviewed in ref. 9).