Interplay between matrix metalloproteinase-9 and tissue inhibitor of matrix metalloproteinase-1 in acute asthma exacerbation and airway remodeling

Background: Airway inflammation and remodeling of extracellular matrix are important features of asthma. Matrix metalloproteinases (MMPs) are group of enzymes expressed in the airways with their inhibitor (tissue inhibitor of MMPs (TIMP) and they are the key responsible for extra cellular matrix (ECM) degradation. Objective: To clarify the role of MMP-9 and TIMP-1 in asthma exacerbation and airway remodeling. Subjects and methods: The study included 3 groups, group “A” included 22 patients with stable asthma group “B” included 18 patients during asthma exacerbation and group “C” of 18 healthy volunteer served as control. All groups were matching age and sex. Levels of MMP-9 and TIMP-1 were measured in the induced sputum of the 3 groups. Serum IgE skin prick test and PEFR were assessed. Results: MMP-9, TIMP-1 and MMP-9/TIMP-1 ratio increased in both A and B groups in comparison to control (P < 0.001). During exacerbation MMP-9 and MMP-9/TIMP-1 ratio showed significant increase for both but TIMP-1 did not show significant change when compared to stable asthmatics. There was significant negative correlation between PEFR and MMP-9, TIMP-1 and MMP-9/TIMP-1 ratio. Conclusion: MMP-9 and TIMP-1 play an important role in pathophysiology of asthma exacerbation and airway remodeling. Clearly, a greater understanding of the pathogenesis of asthma is critical to the development of better therapeutic modalities.