Metalloproteinase-9 in induced sputum correlates with the severity of the late allergen-induced asthmatic response.
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.
Boulay
Marie-Eve
ME
Centre de recherche de l'Hôpital Laval, Institut universitaire de cardiologie et de pneumologie, Université Laval, Sainte-Foy, Que., Canada.
Prince
Philippe
P
Deschesnes
Francine
F
Chakir
Jamila
J
Boulet
Louis-Philippe
LP
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
D000485:Allergens; D019715:Tissue Inhibitor of Metalloproteinase-1; D020780:Matrix Metalloproteinase 9