SERPINE1 and COVID-19: As the fibrinolytic shutdown might coexist with hyper-coagulation in severe COVID-19 patients [21], we next quantified circulating plasminogen activator inhibitor 1 (PAI-1), a common marker of impaired endogenous fibrinolysis that is predominantly released from activated endothelial cells (ECs), to explore if an impaired fibrinolytic pathway could be concomitantly induced upon SARS-CoV-2 infection.