Endothelial cells and blood vessels are major targets for COVID-19-induced tissue injury and spreading to various organs

Table 2 Scenarios by which SARS-CoV-2 elicits endothelial damage

Scenario A: SARS-CoV-2 infection	Scenario B: Cytokine storm
SARS-CoV-2 infects and replicates within vascular ECs and new virus particles are released into the blood vessel. These virions can infect neighboring cells or are carried to distant organs via circulation	↑ IL-6, IL-1β, and TNFα release (cytokine storm) → endothelial damage
	↑ vascular permeability → plasma extravasation
	↑ vWF & FVIII (promote clot formation) and ↑ PAI-1 (inhibits clots lysis) → hypercoagulation

SARS-CoV-2: Severe acute respiratory syndrome coronavirus 2; IL: Interleukin; TNF: Tumor necrosis factor; vWF: von Willebrand factor.