Exhaled breath condensate MMP-9 level and its relationship with asthma severity and interleukin-4/10 levels in children

Background: Matrix metalloproteases (MMPs) are key mediators in airway remodeling, and MMP-9 is the main type investigated to discover its implication for the pathogenesis and severity of asthma. Objective: To evaluate MMP-9 and its natural tissue inhibitors of metalloproteinases (TIMP-1) levels of exhaled breath condensate (EBC) in children with asthma. We also analyzed any potential relationship between these enzymes and EBC interleukin (IL)-4/10 levels as well as asthma severity. Methods: Three study groups were formed: group 1, children with persistent asthma (n = 20); group 2, children with intermittent asthma (n = 10), and group 3, healthy controls (n = 12). Pulmonary functions were measured as forced expiratory volume in 1 second (FEV1), peak expiratory flow (PEF), and forced expiratory flow from 25% to 75% of vital capacity values by spirometry, and MMP-9, TIMP-1 and IL-4/10 levels in EBC were analyzed by enzyme-linked immunosorbent assay (ELISA). Results: The MMP-9 levels of EBC were found to be 57.7 +/- 17.5, 35.4 +/- 11.7, and 30.6 +/- 3.7 ng/mL in children belonging to group 1, group 2 and group 3, respectively. Children belonging to group 1 and group 2 showed significantly higher MMP-9 levels of EBC in comparison with the controls (P < .001 and P < .047, respectively). No statistically significant difference was found between groups regarding TIMP-1 levels of EBC. EBC MMP-9 levels were inversely correlated with both FEV1 and PEF values (r = -0.472, P = .011, and r = -0.571, P = .002, respectively) in children with asthma. Positive correlations were also seen between MMP-9 levels and IL-4/10 levels of EBC (r = 0.419, P = .027 and r = 0.405, P = .032, respectively) in children with asthma. Conclusion: We showed that MMP-9 levels of EBC are elevated in children with asthma and correlated with lung functions and other inflammatory markers such as IL-4/IL10 in EBC. (C) 2012 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.