Immediate Postnatal Concentrations of Metalloproteinase-8 in the Tracheal Aspirates and the Development of Atypical Chronic Lung Disease of Prematurity

ABSTRACT

PURPOSE: Matrix metalloproteinase-8 (MMP-8) is an endoproteinase which degrades extracellular matrix and basement membrane. As early pulmonary inflammation is known to play a key role in the development of chronic lung disease (CLD), we tested the hypothesis that preterm infants who develop CLD have higher concentrations of MMP-8 in the tracheobronchial aspirates (TA) within 24 hours after birth than those who do not develop CLD. METHODS: A retrospective cohort study was done in 70 preterm infants delivered and admitted to the neonatal intensive care unit of Seoul National University Children's Hospital. TA MMP-8 concentrations were measured by ELISA. All patients were categorized into two groups according to the presence of respiratory distress syndrome (RDS). Multiple logistic regression analysis was done to assess the risk factors of CLD. RESULTS: CLD was diagnosed in 46 patients (65.7%). There were no statistically significant differences in the TA MMP-8 concentrations between CLD (+) and CLD (-)group among whole and RDS (+) groups. But in RDS (-)group, TA MMP-8 higher in CLD (+) group than in CLD (-)group. These differences persisted significantly after adjustments for the effects of gestational age at birth and histologic chorioamnionitis [P<0.050, Odds ratio 4.720, 95% CI 1.004-22.196]. The diagnostic indices of MMP-8 concentrations (cutoff, 7.94 ng/mL) as a predictor of development of CLD in RDS (-)group were sensitivity of 82.4%, specificity of 77.8%, positive predictive value of 87.5%, and negative predictive value of 70.0%. CONCLUSION: There was a strong association between increased levels of TA MMP-8 and development of CLD in RDS (-)group. We propose that TA MMP-8 concentrations within 24 hours after birth may be a significant predictor of later development ofatypical CLD.