Sputum matrix metalloproteinase-9: Tissue inhibitor of metalloproteinase-1 ratio in acute asthma

Abstract

Background: The ratio of matrix metalloproteinase-9 (MMP-9) and its inhibitor, tissue inhibitor of metalloproteinase-1 (TIMP-1) may be a marker of the balance between airway tissue destruction and repair. TIMP-1 may potentially contribute to the pathogenesis of increased submucosal extracellular matrix deposition in asthma. Objective: Our purpose was to assess the variation in sputum MMP-9 and TIMP-1 during acute asthma. Methods: We evaluated the MMP-9 and TIMP-1 balance in sputa of 16 asthmatic patients admitted with spontaneous exacerbation, conducting measurement before (day 1) and after methylprednisolone infusion therapy (days 2, 3, 5, and 7), and on remission days. Results: Peak expiratory flow and eosinophilic cationic protein levels were significantly (P < .05) improved within 7 days in all patients. Sputum MMP-9 levels on day 2 tended to be lower than on day 1, but not significantly. Zymography revealed that the main enzyme was identified immunologically as MMP-9, and gelatinase activity on day 1 had a tendency to decrease for the following 7 days. The TIMP-1 levels gradually increased until day 5, were significantly (P