ELEVATED LAMININ CONCENTRATIONS IN LUNG SECRETIONS OF PRETERM INFANTSSUPPORTED BY MECHANICAL VENTILATION ARE CORRELATED WITH RADIOGRAPHIC ABNORMALITIES

Objective: The objective of this study was to test the hypothesis that the presence of laminin in neonatal tracheal aspirates would be indic ative of damage to the structural integrity of the basal laminae of th e lung caused by barotrauma and hyperoxia. We predicted that disruptio n of the basal laminae would be a critical determinant of lung injury and fibrotic repair in the preterm infant whose lungs were ventilated with supplemental oxygen. Study Design: The study group consisted of 2 3 premature infants in the neonatal intensive care unit whose lungs we re ventilated by supplemental oxygen. We quantitated concentrations of laminin and fibronectin from sequential tracheal aspirates by enzyme- linked immunosorbent assays. A two-way analysis of variance was used t o compare laminin and fibronectin concentrations in infants with and w ithout radiographic evidence of coarse pulmonary markings indicative o f fibrotic repair of lung injury. Results: The concentrations of lamin in, but not fibronectin, were significantly higher throughout the firs t 5 weeks of life in infants with abnormal chest radiographs at 36 wee ks after conception. The concentrations of laminin in infant serum wer e approximately 1/30 that of tracheal aspirate laminin concentrations, suggesting that little if any of the laminin detected in the tracheal aspirates was derived from the serum. Conclusions: Increased concentr ations of laminin in tracheal aspirates may be an indication of lung i njury and fibrotic repair in the preterm infant.