title: Neutrophil gelatinase-associated lipocalin: a biomarker in COPD.
abstract: BACKGROUND
  Neutrophil gelatinase-associated lipocalin (NGAL) is an antimicrobial peptide that could be involved in the pathogenesis of COPD. This study aimed to measure the plasma levels of NGAL in a large cohort of patients with COPD and control subjects and examine the levels of NGAL by COPD characteristics.
  
  
  METHODS
  The study included 402 patients with COPD and 229 control subjects aged 40 to 76 years from the Bergen COPD Cohort Study. All patients with COPD had an FEV(1)/FVC ratio of < 0.7, an FEV(1) < 80% predicted, and a smoking history of ≥ 10 pack-years. Plasma levels of NGAL were determined by enzyme immunoassay. Linear regression models were fitted with NGAL as the outcome variable. Confounders examined were sex, age, smoking, Charlson comorbidity score, use of inhaled steroids, neutrophil cell count, plasma creatinine and ferritin, and C-reactive protein.
  
  
  RESULTS
  Mean ± SD plasma concentrations of NGAL were 75.1 ± 31.8 ng/mL in patients with COPD and 56.5 ± 22.0 ng/mL in control subjects (P < .01). NGAL levels were bivariately associated with age, smoking, body composition, Charlson comorbidity score, neutrophil blood count, creatinine, and C-reactive protein but were significantly elevated in patients with COPD, even after adjustment for confounders. Frequent exacerbations and hypoxemia was associated with higher levels of NGAL, whereas increasing Global Initiative for Chronic Obstructive Lung Disease stage was associated with lower levels of NGAL among patients with COPD.
  
  
  CONCLUSIONS
  Plasma levels of NGAL were significantly higher in patients with COPD compared with control subjects. NGAL was related to important COPD characteristics.
authors.affiliation: Department of Thoracic Medicine, Haukeland University Hospital, Bergen, Norway. tomas.eagan@med.uib.no
authors.forename: Tomas M
authors.initials: TM
authors.lastname: Eagan
authors.forename: Jan K
authors.initials: JK
authors.lastname: Damås
authors.forename: Thor
authors.initials: T
authors.lastname: Ueland
authors.forename: Marianne
authors.initials: M
authors.lastname: Voll-Aanerud
authors.forename: Tom E
authors.initials: TE
authors.lastname: Mollnes
authors.forename: Jon A
authors.initials: JA
authors.lastname: Hardie
authors.forename: Per S
authors.initials: PS
authors.lastname: Bakke
authors.forename: Pål
authors.initials: P
authors.lastname: Aukrust
mesh_terms: D000209:Acute-Phase Proteins; D000328:Adult; D000367:Age Factors; D000368:Aged; D015415:Biomarkers / Q000097:blood; D001772:Blood Cell Count; D001823:Body Composition; D002097:C-Reactive Protein / Q000378:metabolism; D016022:Case-Control Studies; D015897:Comorbidity; D003404:Creatinine / Q000097:blood; D005260:Female; D006801:Humans; D016014:Linear Models; D000071068:Lipocalin-2; D054834:Lipocalins / Q000097:blood*; D008297:Male; D008875:Middle Aged; D011518:Proto-Oncogene Proteins / Q000097:blood*; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood* / Q000503:physiopathology; D012129:Respiratory Function Tests; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects
chemical_list: D000209:Acute-Phase Proteins; D015415:Biomarkers; C489506:LCN2 protein, human; D000071068:Lipocalin-2; D054834:Lipocalins; D011518:Proto-Oncogene Proteins; D002097:C-Reactive Protein; D003404:Creatinine