title: Upregulation of reactive oxygen species generation and phagocytosis, and increased apoptosis in human neutrophils during severe sepsis and septic shock.
abstract: We evaluated neutrophil activation by measuring its phagocytic ability and oxidative burst activity in 16 patients with sepsis and 16 healthy volunteers. We also focused on neutrophil apoptosis as a regulatory mechanism of the inflammatory response. Neutrophil phagocytosis was evaluated by the detection of propidium iodide (PI)-labeled Staphylococcus aureus added to whole blood. Reactive oxygen species (ROS) formation was quantified by measuring the oxidation of 2',7' dichlorofluorescein diacetate (DCFH-DA) at baseline and after cell stimulation with phorbol myristate acetate (PMA), and bacterial cells (killed S. aureus) or products (lipopolysaccharide [LPS] and N-formyl-methionyl-leucyl-phenylalanine [FMLP]). Apoptosis was assessed in neutrophils stained with annexin V and PI. Neutrophil phagocytic ability was increased in patients with sepsis compared with healthy controls (median geometric mean fluorescence intensity [GMFI] was 101.9 and 54.7, respectively; P = 0.05). ROS formation was enhanced in patients with sepsis compared with healthy volunteers at baseline (median GMFI 275.6 and 52.1, respectively; P < 0.001), and after stimulation with S. aureus (median GMFI 2395.8 and 454.9, respectively; P < 0.001), PMA (median GMFI 1120.6 and 307.5, respectively; P = 0.003), FMLP (median GMFI 792.4 and 123.2, respectively; P < 0.001), and LPS (median GMFI 624.8 and 144.8, respectively; P < 0.001). Early neutrophil apoptosis was increased in patients with sepsis compared with healthy volunteers (median 11.3% and 9.1%, respectively; P = 0.03). These data demonstrate that neutrophil function is enhanced in patients with sepsis. Additionally, circulating neutrophils from patients with sepsis presented with increased early apoptosis, which may be consequence of a regulatory mechanism of the inflammatory response.
authors.affiliation: Division of Infectious Diseases, Escola Paulista de Medicina, Federal University of São Paulo, São Paulo, Brazil.
authors.forename: Paulo Sergio
authors.initials: PS
authors.lastname: Martins
authors.forename: Esper Georges
authors.initials: EG
authors.lastname: Kallas
authors.forename: Miguel Cendoroglo
authors.initials: MC
authors.lastname: Neto
authors.forename: Maria Aparecida
authors.initials: MA
authors.lastname: Dalboni
authors.forename: Sérgio
authors.initials: S
authors.lastname: Blecher
authors.forename: Reinaldo
authors.initials: R
authors.lastname: Salomão
mesh_terms: D017304:Annexin A5 / Q000494:pharmacology; D017209:Apoptosis; D004396:Coloring Agents / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005452:Fluoresceins / Q000494:pharmacology; D006801:Humans; D008070:Lipopolysaccharides / Q000494:pharmacology; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000473:pathology; D010587:Phagocytosis; D011419:Propidium / Q000494:pharmacology; D017382:Reactive Oxygen Species; D016897:Respiratory Burst; D018805:Sepsis / Q000473:pathology*; D012769:Shock / Q000473:pathology*; D013211:Staphylococcus aureus / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D017304:Annexin A5; D004396:Coloring Agents; D004791:Enzyme Inhibitors; D005452:Fluoresceins; D008070:Lipopolysaccharides; D017382:Reactive Oxygen Species; C029569:diacetyldichlorofluorescein; D011419:Propidium; D009240:N-Formylmethionine Leucyl-Phenylalanine