title: Metalloproteinase-9 in induced sputum correlates with the severity of the late allergen-induced asthmatic response.
abstract: BACKGROUND
  Asthma is characterized by airway inflammation and remodeling in which matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMP) play an important role. Allergen exposure activates the inflammatory/repair process in sensitized subjects. Induced-sputum analysis is a non-invasive method that allows the assessment of changes in inflammatory and remodeling mediators implicated in asthma.
  
  
  OBJECTIVE
  To evaluate the changes in MMP-9 and its principal inhibitor (TIMP-1) in sputum and plasma of mild allergic asthmatic subjects after whole-lung allergen challenge.
  
  
  METHODS
  Induced sputum and blood samples were obtained at baseline, and 6 and 24 h after challenge. MMP-9 and TIMP-1 levels in sputum and plasma were measured by ELISA.
  
  
  RESULTS
  Allergen challenge increased the percentage of sputum eosinophils and MMP-9 levels 6 and 24 h after the challenge compared to baseline levels, but TIMP-1 levels did not vary significantly. A significant correlation was observed between MMP-9 levels at 6 h and the maximum percent fall in FEV(1) during the late response. Throughout the study, MMP-9 levels correlated significantly with the number of neutrophils in sputum.
  
  
  CONCLUSIONS
  This study shows that analysis of induced sputum is a useful tool to study the variations in MMP-9 and TIMP-1 levels following allergen challenge, therefore allowing to evaluate their role in allergen-induced airway damage and repair.
authors.affiliation: Centre de recherche de l'Hôpital Laval, Institut universitaire de cardiologie et de pneumologie, Université Laval, Sainte-Foy, Que., Canada.
authors.forename: Marie-Eve
authors.initials: ME
authors.lastname: Boulay
authors.forename: Philippe
authors.initials: P
authors.lastname: Prince
authors.forename: Francine
authors.initials: F
authors.lastname: Deschesnes
authors.forename: Jamila
authors.initials: J
authors.lastname: Chakir
authors.forename: Louis-Philippe
authors.initials: LP
authors.lastname: Boulet
mesh_terms: D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000009:adverse effects*; D001249:Asthma / Q000276:immunology*; D005260:Female; D006801:Humans; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000032:analysis*; D012720:Severity of Illness Index; D013183:Sputum / Q000737:chemistry; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000032:analysis
chemical_list: D000485:Allergens; D019715:Tissue Inhibitor of Metalloproteinase-1; D020780:Matrix Metalloproteinase 9