ANGPT2 and acute respiratory distress syndrome: Interventions that attenuate endothelial barrier disruption strongly reduce mortality in animal models of sepsis or ARDS4–6; vice versa impairment of barrier-protective mechanisms has a deleterious effect on sepsis phenotype.7 Although direct measurement of vascular leak in patients remains challenging, clinical surrogate measures of vascular leak8 and circulating biomarkers of endothelial injury like Ang-2 (angiopoietin-2)9 directly relate to and predict mortality of sepsis and ARDS, independent of comorbidity.