Angiopoietin-2 associations with the underlying infection and sepsis severity

•Circulating Ang-2 in sepsis is associated with the underlying infection.•Ang-2 is mostly increased in infections coming from sites other than the lung.•Among organ failures, Ang-2 is increased in coagulopathy and metabolic acidosis.•Circulating monocytes are an independent site of Ang-2 production.•Gene expression in monocytes is associated with final outcome.

Angiopoietin-2 (Ang-2) is an important mediator in sepsis. We have previously shown that endotoxemia levels are related to the underlying infection and affect septic patients’ outcome. Based on this background we now investigated if circulating Ang-2 (cAng-2) and monocyte Ang-2 expression in septic patients are associated with the underlying infection and organ failure. We measured cAng-2 in 288 septic patients (121 with sepsis, 167 with severe sepsis/septic shock) at less than 24 h post study inclusion (day 1) and on days 3 and 7. Peripheral blood mononuclear cells (PBMCs) were additionally isolated; Ang-2 gene expression was estimated by means of real-time PCR. Levels of cAng-2 were higher under severe sepsis and septic shock, as compared to uncomplicated sepsis; PBMC Ang-2 copies were higher in severe sepsis. On day 1, cAng-2 and Ang-2 gene copies were greater under severe sepsis/septic shock in sufferers from all types of infections with the exception of community-acquired pneumonia and ventilator-associated pneumonia. cAng-2 increased proportionally to the number of failing organs, and was higher under metabolic acidosis and acute coagulopathy as compared to no failing organ. On day 1, copies of Ang-2 were higher in survivors, whereas cAng-2 was higher in non-survivors. In a large cohort of septic patients, cAng-2 kinetics appears associated with the underlying infection and organ failure type.