Fig. 1.

Balance between a healthy and a dysfunctional endothelium. Equilibrium shift to the left characterizes a quiescent state and functional endothelium while the shift to the right indicates the effectual weight of vasoconstriction (↓NO, PGI2), oxidative stress (↑ROS), proinflammatory cytokines (TNF-α, IL-6, MCP-1) and adhesion molecules (↑ICAM, VCAM, E-selectin) as well as procoagulants (↑PAI-1, vWF, P-selectin), which characterize endothelial dysfunction. During infection or in a disease state, the balance is tipped downward, and the endothelium is activated and dysfunctional. This leads to systemic inflammation, oxidative damage, impaired vasculature, and increased permeability and ultimately accelerates disease progression.