title: Osteopontin, asbestos exposure and pleural plaques: a cross-sectional study.
abstract: BACKGROUND
  Osteopontin (OPN) is a plasma protein/cytokine produced in excess in several malignancies. In a recent study OPN was reported as being related to the duration of asbestos exposure and presence of benign asbestos-related diseases; however, it was unclear whether this protein was an indicator of exposure or effect.
  
  
  METHODS
  In 193 workers, 50 with pleural plaques (PP), in whom different indicators of past asbestos exposure were estimated, OPN plasma levels were assessed using commercial quantitative sandwich enzyme immunoassays according to the manufacturer's instructions.
  
  
  RESULTS
  Osteopontin increased with increasing age and several aspects of asbestos exposure, without differences related to the presence of pleural plaques. At multivariable regression analysis, the explanatory variables with a significant independent influence on OPN were length of exposure (positive correlation) and time elapsed since last exposure (positive correlation).
  
  
  CONCLUSIONS
  Since asbestos in lung tissue tends to wane over time, OPN should decrease (rather than increase) with time since last exposure. Therefore, OPN cannot be a reliable biomarker of exposure nor effect (presence of pleural plaques).
authors.affiliation: Department of Environmental Medicine and Public Health, Padua University, Padua, Italy. giuseppe.mastrangelo@unipd.it
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Mastrangelo
authors.forename: Gianluca
authors.initials: G
authors.lastname: Marangi
authors.forename: Maria N
authors.initials: MN
authors.lastname: Ballarin
authors.forename: Silvia
authors.initials: S
authors.lastname: Michilin
authors.forename: Aline S C
authors.initials: AS
authors.lastname: Fabricio
authors.forename: Flavio
authors.initials: F
authors.lastname: Valentini
authors.forename: John H
authors.initials: JH
authors.lastname: Lange
authors.forename: Ugo
authors.initials: U
authors.lastname: Fedeli
authors.forename: Luca
authors.initials: L
authors.lastname: Cegolon
authors.forename: Massimo
authors.initials: M
authors.lastname: Gion
mesh_terms: D000368:Aged; D001194:Asbestos / Q000633:toxicity*; D001195:Asbestosis / Q000097:blood; D015415:Biomarkers / Q000097:blood; D003430:Cross-Sectional Studies; D006801:Humans; D008875:Middle Aged; D009784:Occupational Diseases / Q000097:blood* / Q000175:diagnosis; D016273:Occupational Exposure / Q000009:adverse effects*; D053495:Osteopontin / Q000097:blood*; D010995:Pleural Diseases / Q000097:blood* / Q000175:diagnosis; D015203:Reproducibility of Results; D013997:Time Factors
chemical_list: D015415:Biomarkers; D053495:Osteopontin; D001194:Asbestos