Significance of Interleukin-6 and Ureaplasma urealyticum Detected by Polymerase Chain Reaction in the Tracheal Aspirates at Birth for the Development of Chronic Lung Disease (CLD) of Prematurity and the Risk Factors for the Different Types of CLD accordin

PURPOSE: To analyze the significance of interleukin-6 (IL-6) concentration and Ureaplasma urealyticum (UU) from tracheal aspirates (TA) taken immediately after birth in the development of chronic lung disease of prematurity (CLD), and to analyze the risk factors for CLD according to the preceding illnesses. METHODS: A retrospective cohort study was done in 75 inborn preterm infants admitted to a university hospital NICU and intubated at birth for the respiratory care. TA was taken to measure IL-6 by ELISA and to perform UU PCR. The patients were grouped into four, according to the history of respiratory distress syndrome (RDS) and chorioamnionitis (CA). RESULTS: PCR positive rate of UU was 25.3%. Positive PCR was significantly frequent in the patients with CLD or CA. IL-6 in TA was significantly higher with CLD, CA, or positive PCR. Risk factors for CLD were increased IL-6, positive UU PCR, and PDA in all patients. The risk factors for CLD were PDA in RDS(+)CA(-) group [OR 2.11; 95% CI 1.15-3.89]; PDA [OR 12.0; 95% CI 2.50-57.67] and IL-6 (>284.7 pg/mL) [OR 3.75; 95% CI 1.01-13.90] in RDS(+)CA(+) group; and IL-6 (>284.7 pg/mL) [OR 8.25; 95% CI 1.54-44.14] in RDS(-)CA(+) group. CONCLUSION: PDA was a risk factor for CLD following RDS and increased IL-6 for CLD following CA. Inflammatory response of fetal lung, measured by IL-6 and UU PCR in TA at birth in preterm infants, was associated with CA and might be a risk factor for the development of CLD.

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

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.