title: Leptin as local inflammatory marker in COPD.
abstract: BACKGROUND
  Chronic inflammation of the lung is a characteristic finding in chronic obstructive pulmonary disease (COPD). Leptin is a pleiotropic cytokine thought to play a role in host response to inflammation. As recent studies have shown that leptin receptors are present in the lung, this study aimed to determine if leptin is detectable in induced sputum of COPD patients and if there is a relationship between leptin and other inflammatory markers in sputum.
  
  
  METHODS
  Sputum was induced in 14 male patients with moderate COPD (FEV1: 56 (15) % pred.). Leptin, total tumour necrosis factor (TNF)-alpha, and C-reactive protein (CRP) were analyzed in induced sputum supernatant by ELISA. Leptin was also determined in EDTA plasma.
  
  
  RESULTS
  Leptin was detectable in induced sputum of 10 COPD patients. A significant relationship was found between sputum leptin and CRP (r = 0.943, P < 0.001) and total TNF-alpha (r = 0.690, P < 0.01). Plasma leptin and sputum leptin were inversely correlated (r = -0.643, P < 0.01).
  
  
  CONCLUSIONS
  The present study demonstrated that leptin is detectable in induced sputum of patients with moderate COPD and is related to other inflammatory markers. The observed correlations between leptin and inflammatory markers in sputum may indicate that leptin is involved in the local inflammatory response in COPD.
authors.affiliation: Department of Respiratory Medicine, Nutrition and Toxicology Research Institute Maastricht, University Hospital Maastricht, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands. r.broekhuizen@pul.unimaas.nl
authors.forename: R
authors.initials: R
authors.lastname: Broekhuizen
authors.forename: J H J
authors.initials: JH
authors.lastname: Vernooy
authors.forename: A M W J
authors.initials: AM
authors.lastname: Schols
authors.forename: M A
authors.initials: MA
authors.lastname: Dentener
authors.forename: E F M
authors.initials: EF
authors.lastname: Wouters
mesh_terms: D000328:Adult; D000368:Aged; D000886:Anthropometry; D015415:Biomarkers / Q000378:metabolism; D002097:C-Reactive Protein / Q000378:metabolism; D005541:Forced Expiratory Volume; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism; D020738:Leptin / Q000032:analysis / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000378:metabolism* / Q000503:physiopathology; D013183:Sputum / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D014797:Vital Capacity
chemical_list: D015415:Biomarkers; D018836:Inflammation Mediators; D020738:Leptin; D014409:Tumor Necrosis Factor-alpha; D002097:C-Reactive Protein