Dexamethasone therapy in preterm infants developing bronchopulmonary dysplasia: effect on pulmonary surfactant disaturated-phosphatidylcholine kinetics

Abstract

The role of corticosteroid in severe bronchopulmonary dyplasia (BPD) is still debated. Scanty data are available on the corticosteroids effect on surfactant metabolism. Our objective was to compare surfactant kinetics in preterm infants with developing BPD, before and after dexamethasone (DEXA) treatment. Twenty-eight studies were performed in 14 preterm infants (birth weight 786 +/- 192 g, gestational age 26 +/- 1 wk) on high ventilatory setting, before (age 22 +/- 11 d) and after (age 33 +/- 11 d) DEXA. C-labeled dipalmitoyl-phosphatidylcholine (DPPC) was administered endotrachelly to trace pulmonary surfactant. Surfactant disaturated-phosphatidylcholine (DSPC) kinetics and pools were calculated from DSPC C-enrichment curves of serial tracheal aspirates and bi-compartmental analysis. Total protein and myeloperoxidase (MPO) activity in tracheal aspirates were also measured and expressed per ml of Epithelial Lining Fluid (ELF). After DEXA, DSPC alveolar pool increased significantly from 8.2 +/- 7.6 to 10.6 +/- 11.3 mg/kg (p = 0.039), total proteins and MPO were reduced from 8.8 +/- 8.6 to 3.1 +/- 2.1 mg/ml ELF (p = 0.046) and from 1822 +/- 1224 to 1261 +/- 987 mU/mlELF (p = 0.028) respectively. In conclusion, DEXA treatment in mechanically ventilated preterm infants with severe respiratory failure and at high risk of developing BPD, significantly reduced inflammatory markers and increased alveolar surfactant DSPC pool.