title: Neutrophil extracellular trap formation and extracellular DNA in sputum of stable COPD patients.
abstract: BACKGROUND
  Chronic obstructive pulmonary disease (COPD) is characterized by neutrophilic airway inflammation. Neutrophil extracellular trap (NET) formation - a meshwork of neutrophil DNA components and neutrophil enzymes are involved in innate immunity and inflammation. Little is known about the presence of these structures in induced sputum from stable COPD patients.
  
  
  METHODS
  Induced sputum samples of 23 COPD patients and 10 healthy controls were collected. Sputum cells were harvested, cultivated and stained for NET components. Extracellular DNA was quantified using a NanoDrop 2000 spectrophotometer.
  
  
  RESULTS
  NET formation was markedly upregulated in COPD sputum compared with healthy controls, irrespective of sputum purulence or smoking status. NET formation was associated with significantly higher concentration of extracellular DNA in sputum supernatant (484 ng/μl in COPD versus 268 ng/μl in controls, p = 0.013). Log-transformed extracellular DNA correlated with log-transformed absolute neutrophil numbers in sputum (r = 0.60; p < 0.001) and airway obstruction (r = -0.43; p = 0.013).
  
  
  CONCLUSIONS
  NET formation associated with higher concentrations of extracellular DNA may be a pathobiological feature of COPD-derived sputum neutrophils.
authors: Pulmonary Research Institute at Lung Clinic Grosshansdorf, Airway Research Center North (ARCN), Member of the German Center for Lung Research, Grosshansdorf, Germany; Lung Clinic Grosshansdorf, Airway Research Center North (ARCN), Member of the German Center for Lung Research, Grosshansdorf, Germany. Electronic address: f.pedersen@pulmoresearch.de.
authors: Frauke
authors: F
authors: Pedersen
authors: Clinical and Experimental Pathology, Research Center Borstel, Airway Research Center North, Member of the German Center for Lung Research, Borstel, Germany.
authors: Sebastian
authors: S
authors: Marwitz
authors: Fraunhofer ITEM, Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research, Hannover, Germany.
authors: Olaf
authors: O
authors: Holz
authors: Pulmonary Research Institute at Lung Clinic Grosshansdorf, Airway Research Center North (ARCN), Member of the German Center for Lung Research, Grosshansdorf, Germany.
authors: Anne
authors: A
authors: Kirsten
authors: Lung Clinic Grosshansdorf, Airway Research Center North (ARCN), Member of the German Center for Lung Research, Grosshansdorf, Germany.
authors: Thomas
authors: T
authors: Bahmer
authors: Lung Clinic Grosshansdorf, Airway Research Center North (ARCN), Member of the German Center for Lung Research, Grosshansdorf, Germany.
authors: Benjamin
authors: B
authors: Waschki
authors: Pulmonary Research Institute at Lung Clinic Grosshansdorf, Airway Research Center North (ARCN), Member of the German Center for Lung Research, Grosshansdorf, Germany.
authors: Helgo
authors: H
authors: Magnussen
authors: Lung Clinic Grosshansdorf, Airway Research Center North (ARCN), Member of the German Center for Lung Research, Grosshansdorf, Germany.
authors: Klaus F
authors: KF
authors: Rabe
authors: Clinical and Experimental Pathology, Research Center Borstel, Airway Research Center North, Member of the German Center for Lung Research, Borstel, Germany.
authors: Torsten
authors: T
authors: Goldmann
authors: Respiratory, Inflammation & Autoimmunity iMED, AstraZeneca, R&D Mölndal, Sweden.
authors: Mohib
authors: M
authors: Uddin
authors: Pulmonary Research Institute at Lung Clinic Grosshansdorf, Airway Research Center North (ARCN), Member of the German Center for Lung Research, Grosshansdorf, Germany.
authors: Henrik
authors: H
authors: Watz
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D004247:DNA / Q000032:analysis / Q000235:genetics*; D065206:Extracellular Traps / Q000378:metabolism; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D064368:Healthy Volunteers; D006801:Humans; D007249:Inflammation / Q000378:metabolism / Q000473:pathology; D008297:Male; D008856:Microscopy, Fluorescence / Q000379:methods; D008875:Middle Aged; D009504:Neutrophils / Q000378:metabolism* / Q000473:pathology*; D029424:Pulmonary Disease, Chronic Obstructive / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D012907:Smoking / Q000009:adverse effects / Q000276:immunology; D013183:Sputum / Q000378:metabolism*
chemical_list: D004247:DNA
keywords: COPD; Chronic inflammation; Extracellular DNA; Neutrophil extracellular traps (NET); Sputum