THBD and COVID-19: Increased circulating levels of soluble forms of adhesion molecules, such as endoglin, VCAM-1, and ICAM-1 [83,84] as well as biomarkers of NO impairment, such as L-arginine and asymmetric dimethylarginine (ADMA) [77], and markers of endothelial activation, such as thrombomodulin, P-selectin, vWF [85], and angiopoietin-2 [84,86] have all been reported in COVID-19 patients and have been individually associated to the severity and mortality of COVID-19.