Assessing airway repair capacity in very preterm infants

Introduction: Airway epithelial cells (AECs) line the airway to create a protective barrier between the lung and the external environment. Very preterm birth ( Methods: Nasal brushings were used to collect AECs from infants born very preterm (n=35, 24-31.7wks gestation, 1.07-1.22yrs corrected at sampling). Control samples were provided by children born at term (n=6, >37wks gestation, 2.4-6.5yrs at sampling). Cultured AECs were scratch wounded and repair tracked for 72 hours (IncuCyte ZOOM®, Essen Bioscience). Wound closure was then assessed for correlations with neonatal factors including gestation, birthweight, duration of respiratory support, and steroid exposure. Results: Term AECs achieved complete repair within 60 hours. Repair in successfully cultured preterm AECs (n=22) was significantly altered and fell into three categories; delayed but complete repair (>80% n=5), significant but incomplete closure (50-80% n=6) and incomplete closure (20-50% n=10). Neonatal factors did not predict altered wound repair, though infants born to mothers completing a course of antenatal steroids (n=13) exhibited significantly worse repair (p=0.017, 47.30% vs 74.02%). Conclusion: Data confirm that preterm infants have an intrinsic functional defect in their airway reparative capacity. Exposure to antenatal steroids may further alter repair and raises questions about the long-term impact of antenatal steroid use.