Correlates of Elevated Interleukin-6 and 8-Hydroxy-2′-Deoxyguanosine Levels in Tracheal Aspirates from Very Low Birth Weight Infants Who Develop Bronchopulmonary Dysplasia

Abstract

Bronchopulmonary dysplasia (BPD) remains the most common complication of very low birth weight (VLBW) preterm infants, and inflammatory regulation plays a role in the development of the BPD. Interleukin-6 (IL-6) has an important role in airway inflammation and therefore can be used as a marker of airway injury. The study aimed to compare the changes between IL-6 and oxidative stress marker with 8-hydroxy-2′-deoxyguanosine (8-OHdG) from serum and tracheal aspiration (TA) in VLBW preterm infants following development of BPD. Methods: This birth cohort study enrolled 80 VLBW preterm infants, including 26 who developed BPD. All infants completed the study and survived at 36 weeks postmenstrual age. IL-6 and 8-OHdG concentrations from serum and TA on Day 1 and Day 28 after birth were measured using immunoassay. Results: IL-6 and 8-OHdG in serum and TA were higher in the BPD group than in the non-BPD group on the 1st day after birth (p < 0.05). The IL-6 and 8-OHdG levels in TA fluid were persistently increased on the 28th day of life in the BPD group (p < 0.05). The TA IL-6 was positively correlated with 8-OHdG levels on the 1st day (r = 0.64, p < 0.05) and 28th day of life (r = 0.76, p < 0.05). Based on receiver operating characteristic curves as a predictor of BPD development, TA IL-6 (cutoff, 456.8 pg/mg) had 81.5% sensitivity and 77.8% specificity, whereas TA 8-OHdG (cutoff, 4.4 ng/mg) had a sensitivity of 81.5% and a specificity of 64.4%. Conclusion: Persistent inflammation with oxidative DNA damage in the respiratory tract may be a crucial mechanism in BPD.

Keywords

• 8-hydroxydeoxyguanosine
• bronchopulmonary dysplasia
• premature infant