Multiple logistic regression analysis performed using the baseline sE- and sP-selectin levels, PCT levels, SOFA scores and the biological rationale for targeting markers of endothelial activation
and dysfunction as biomarkers of the septic syndrome. Hence, we hypothesized that levels of endothelial biomarkers at ICU entry may predict subsequent sepsis development.
Ang-1, which maintains vessel integrity and inhibits vascular leakage and Ang-2, which disrupts the protective effects of Ang-1-Tie2 signaling, are antagonistic factors that trigger endothelial
cell activation. In critically-ill patients, the release of Ang-2 directly reflects vascular barrier breakdown and has been proposed to be a potentially strong biomarker in sepsis. Ang-2 levels are higher in patients with severe sepsis compared to patients with or without SIRS or sepsis and increased Ang-2 plasma levels have been associated with worst clinical outcome in patients with major trauma and severe sepsis or shock , and in non-survivors compared to survivors . Fewer studies have focused on Ang-1, showing either decreased levels in critically-ill septic or non-septic patients compared to healthy controls, or associating decreased levels at ICU admission with higher mortality. Plasma levels of VEGF, which stimulates proliferation of vascular endothelial cells, have also been associated with disease severity and mortality. VE-cad-herin controls cohesion of intercellular junctions and maintains EC integrity. Increased levels of sVE-cadherin have been associated with poor outcome in severe sepsis , while the high circulating levels found in patients with sepsis probably reflect decreased molecule levels in regions of endothelial cell–cell contact and dis-
ruption of the endothelial barrier. Finally, vWF antigen, an endothelial product that mediates platelet adhesion at sites of vascular damage, has been reported to be higher in patients with
sepsis than those without. Despite this promising background information, all the above molecules were measured at ICU entry in our critically ill, initially non-septic cohort, and no differentiation was found between patients who subsequently became septic and those who did not. It should be stressed that unlike the studies mentioned above, all our samples were obtained at Day 1 of ICU
admission, in individuals who met no criteria for sepsis at that time point