title: Mechanical ventilation induces neutrophil extracellular trap formation.
abstract: BACKGROUND
  Mechanical ventilation can injure the lung and induce a proinflammatory state; such ventilator-induced lung injury (VILI) is associated with neutrophil influx. Neutrophils release DNA and granular proteins as cytotoxic neutrophil extracellular traps (NETs). The authors hypothesized that NETs were produced in a VILI model and may contribute to injury.
  
  
  METHODS
  In a two-hit lipopolysaccharide/VILI mouse model with and without intratracheal deoxyribonuclease (DNase) treatment or blockade of known inducers of NET formation (NETosis), the authors assessed compliance, bronchoalveolar lavage fluid protein, markers of NETs (citrullinated histone-3 and DNA), and markers of inflammation.
  
  
  RESULTS
  Although lipopolysaccharide recruited neutrophils to airways, the addition of high tidal mechanical ventilation was required for significant induction of NETs markers (e.g., bronchoalveolar lavage fluid DNA: 0.4 ± 0.07 µg/ml [mean ± SEM], P < 0.05 vs. all others, n = 10 per group). High tidal volume mechanical ventilation increased airway high-mobility group box 1 protein (0.91 ± 0.138 vs. 0.60 ± 0.095) and interleukin-1β in lipopolysaccharide-treated mice (22.4 ± 0.87 vs. 17.0 ± 0.50 pg/ml, P < 0.001) and tended to increase monocyte chemoattractant protein-1 and interleukin-6. Intratracheal DNase treatment reduced NET markers (bronchoalveolar lavage fluid DNA: 0.23 ± 0.038 vs. 0.88 ± 0.135 µg/ml, P < 0.001; citrullinated histone-3: 443 ± 170 vs. 1,824 ± 403, P < 0.01, n = 8 to 10) and attenuated the loss of static compliance (0.9 ± 0.14 vs. 1.58 ± 0.17 ml/mmHg, P < 0.01, n = 19 to 20) without significantly impacting other measures of injury. Blockade of high-mobility group box 1 (with glycyrrhizin) or interleukin-1β (with anakinra) did not prevent NETosis or protect against injury.
  
  
  CONCLUSIONS
  NETosis was induced in VILI, and DNase treatment eliminated NETs. In contrast to experimental transfusion-related acute lung injury, NETs do not play a major pathogenic role in the current model of VILI.
authors: From the Program in Physiology and Experimental Medicine, SickKids Research Institute, Toronto, Ontario, Canada (C.Y., N.P., G.O., M.A.K., M.P., K.T., R.B., A.M., D.E., B.P.K.); Department of Laboratory Medicine and Pathobiology (C.Y., N.P., M.P.), Department of Anesthesia (B.P.K.), Department of Pediatrics (M.P., K.T.), Department of Physiology (M.P., W.M.K., K.T., A.M., B.P.K.), and Institute of Medical Sciences (N.P., W.M.K.), University of Toronto, Toronto, Ontario, Canada; Keenan Research Centre for Biomedical Science of St. Michael's Hospital, Toronto, Ontario, Canada (W.M.K.); and Department of Critical Care, Hospital for Sick Children, Toronto, Ontario, Canada (B.P.K.).
authors: Christopher
authors: C
authors: Yildiz
authors: Nades
authors: N
authors: Palaniyar
authors: Gail
authors: G
authors: Otulakowski
authors: Meraj A
authors: MA
authors: Khan
authors: Martin
authors: M
authors: Post
authors: Wolfgang M
authors: WM
authors: Kuebler
authors: Keith
authors: K
authors: Tanswell
authors: Rosetta
authors: R
authors: Belcastro
authors: Azhar
authors: A
authors: Masood
authors: Doreen
authors: D
authors: Engelberts
authors: Brian P
authors: BP
authors: Kavanagh
mesh_terms: D055371:Acute Lung Injury / Q000209:etiology / Q000378:metabolism; D000818:Animals; D065206:Extracellular Traps / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D020556:Neutrophil Infiltration / Q000502:physiology; D009504:Neutrophils / Q000378:metabolism*; D011897:Random Allocation; D012121:Respiration, Artificial / Q000009:adverse effects*; D013990:Tidal Volume / Q000502:physiology