title: Angiopoietin-2 is increased in septic shock: evidence for the existence of a circulating factor stimulating its release from human monocytes.
abstract: We aimed to investigate if angiopoietin-2 (Ang-2) participates in the septic process and what may be the role of monocytes as a site of release of Ang-2 in sepsis. Concentrations of Ang-2 were estimated in sera and in supernatants of monocytes derived form one already described cohort of 90 patients with septic syndrome due to ventilator-associated pneumonia (VAP). Mononuclear cells of 17 healthy volunteers were stimulated by serum of patients in the presence or absence of various intracellular pathway inhibitors. Ang-2 gene expression after stimulation was also tested. Ang-2 was higher in patients with septic shock compared to patients with sepsis, severe sepsis and controls. Ang-2 was significantly increased in non-survivors compared with survivors. Serum levels greater than 9700 pg/ml were accompanied by a 3.254 odds ratio for death (p: 0.033). Ang-2 release from monocytes of septic patients was slightly decreased after stimulation with lipopolysaccharide (LPS) of Escherichia coli O55:B5. Release of Ang-2 from healthy mononuclear cells was stimulated by serum of patients with shock but not by serum of non-shocked patients (p: 0.016). Release was decreased by LPS; increased in the presence of a TLR4 antagonist; and decreased by anti-TNF antibody. RNA transcripts of PBMCs after stimulation with serum of patients with septic shock were higher than those after LPS stimulation. It is concluded that Ang-2 is increased in serum in the event of septic shock and that its increase is related to unfavorable outcome. It seems that a circulating factor may exist in the serum of patients with septic shock that stimulates gene expression and subsequent release of Ang-2 from monocytes. TLR4 and TNFalpha modulate release of Ang-2.
authors.affiliation: 4th Department of Internal Medicine, University of Athens, Medical School, Greece.
authors.forename: Hariklia
authors.initials: H
authors.lastname: Kranidioti
authors.forename: Stylianos E
authors.initials: SE
authors.lastname: Orfanos
authors.forename: Ilia
authors.initials: I
authors.lastname: Vaki
authors.forename: Anastasia
authors.initials: A
authors.lastname: Kotanidou
authors.forename: Maria
authors.initials: M
authors.lastname: Raftogiannis
authors.forename: Ioanna
authors.initials: I
authors.lastname: Dimopoulou
authors.forename: Antigoni
authors.initials: A
authors.lastname: Kotsaki
authors.forename: Athina
authors.initials: A
authors.lastname: Savva
authors.forename: Andreas
authors.initials: A
authors.lastname: Papapetropoulos
authors.forename: Apostolos
authors.initials: A
authors.lastname: Armaganidis
authors.forename: Evangelos J
authors.initials: EJ
authors.lastname: Giamarellos-Bourboulis
mesh_terms: D000328:Adult; D042702:Angiopoietin-2 / Q000097:blood*; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000097:blood; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D009000:Monocytes / Q000187:drug effects / Q000276:immunology*; D011379:Prognosis; D011446:Prospective Studies; D012772:Shock, Septic / Q000097:blood* / Q000276:immunology*; D051197:Toll-Like Receptor 4 / Q000037:antagonists & inhibitors / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000097:blood; D055815:Young Adult
chemical_list: D042702:Angiopoietin-2; C508600:IL6 protein, human; D015850:Interleukin-6; D008070:Lipopolysaccharides; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha