title: Increased levels of osteopontin in sputum supernatant in patients with COPD.
abstract: BACKGROUND
  Osteopontin (OPN) is a phosphorylated acidic glycoprotein that can function as both an extracellular matrix molecule and a cytokine. Published data support that OPN is upregulated in surgical lung tissue samples of patients with COPD. The aim of this study was to determine the levels of OPN in sputum supernatants of patients with COPD and to investigate possible associations with mediators and cells involved in the inflammatory and remodeling process as well as with the extent of emphysema.
  
  
  METHODS
  Seventy-seven patients with COPD and 40 healthy subjects (20 smokers) were studied. All subjects underwent lung function tests, sputum induction for cell count identification, and OPN, transforming growth factor-β1, matrix metalloproteinase (MMP)-2, IL-8, and leukotriene-4 measurement in sputum supernatants. High-resolution CT (HRCT) scan of the chest was performed for quantification of emphysema.
  
  
  RESULTS
  OPN levels (pg/mL) were significantly higher in patients with COPD compared with healthy smokers and nonsmokers (median [interquartile range], 1,340 [601, 6,227] vs 101 [77, 110] vs 68 [50, 89], respectively; P < .001). Regression analysis showed a significant association between OPN and sputum neutrophils, IL-8, MMP-2, and the extent of emphysema. The associations previously listed were not observed in healthy subjects.
  
  
  CONCLUSIONS
  OPN levels are higher in patients with COPD compared with healthy subjects. OPN may play a role in the neutrophilic inflammation and in the pathogenesis of emphysema.
authors.affiliation: 1st Respiratory Medicine Department, University of Athens, Medical School, 401 Military Hospital, Athens, Greece.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Papaporfyriou
authors.affiliation: Department of Respiratory and Critical Care Medicine, Research Unit, "Sotiria" Chest Hospital, 401 Military Hospital, Athens, Greece.
authors.forename: Stelios
authors.initials: S
authors.lastname: Loukides
authors.affiliation: 2nd Respiratory Medicine Department, University of Athens, Medical School, "Attikon" Hospital, 401 Military Hospital, Athens, Greece.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Kostikas
authors.affiliation: Marianthi Simou Laboratories, University of Athens, Medical School, 401 Military Hospital, Athens, Greece.
authors.forename: Davina C M
authors.initials: DCM
authors.lastname: Simoes
authors.affiliation: Department of Microbiology, 401 Military Hospital, Athens, Greece.
authors.forename: Georgios
authors.initials: G
authors.lastname: Papatheodorou
authors.affiliation: 1st Respiratory Medicine Department, University of Athens, Medical School, 401 Military Hospital, Athens, Greece.
authors.forename: Elissavet
authors.initials: E
authors.lastname: Konstantellou
authors.affiliation: Department of Respiratory and Critical Care Medicine, Research Unit, "Sotiria" Chest Hospital, 401 Military Hospital, Athens, Greece.
authors.forename: Georgios
authors.initials: G
authors.lastname: Hillas
authors.affiliation: 2nd Respiratory Medicine Department, University of Athens, Medical School, "Attikon" Hospital, 401 Military Hospital, Athens, Greece.
authors.forename: Spyros
authors.initials: S
authors.lastname: Papiris
authors.affiliation: 1st Respiratory Medicine Department, University of Athens, Medical School, 401 Military Hospital, Athens, Greece.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Koulouris
authors.affiliation: 1st Respiratory Medicine Department, University of Athens, Medical School, 401 Military Hospital, Athens, Greece. Electronic address: petros44@hotmail.com.
authors.forename: Petros
authors.initials: P
authors.lastname: Bakakos
mesh_terms: D000368:Aged; D004646:Emphysema / Q000378:metabolism / Q000503:physiopathology; D005260:Female; D006801:Humans; D016209:Interleukin-8 / Q000378:metabolism; D007975:Leukotriene B4 / Q000378:metabolism; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D008875:Middle Aged; D053495:Osteopontin / Q000378:metabolism*; D029424:Pulmonary Disease, Chronic Obstructive / Q000378:metabolism* / Q000503:physiopathology; D012129:Respiratory Function Tests; D013183:Sputum / Q000378:metabolism*; D053773:Transforming Growth Factor beta1 / Q000378:metabolism*
chemical_list: C508606:CXCL8 protein, human; D016209:Interleukin-8; D053773:Transforming Growth Factor beta1; D053495:Osteopontin; D007975:Leukotriene B4; C522361:MMP2 protein, human; D020778:Matrix Metalloproteinase 2