Plasma endothelin-1 like immunoreactivity levels in neonates.

We attempted to determine the plasma endothelin-1-like immunoreactivity (ET-1) levels and to evaluate its physiological significance in 29 neonates: 5 with respiratory distress syndrome (RDS), 3 with transient tachypnoea of the newborn (TTN), 4 with neonatal asphyxia, 5 with bronchopulmonary dysplasia (BPD) following RDS, 7 healthy preterm infants and 5 healthy full-term infants. Plasma ET-1 levels in infants with RDS were significantly higher than those in healthy full-term infants through the 1st week of life. Plasma ET-1 levels in infants with neonatal asphyxia were high on the first 2 days of life and then gradually decreased to those of healthy full-term infants. Plasma levels in infants with TTN were the same as those in healthy full-term infants. Plasma ET-1 levels in infants with BPD were high when compared with those in healthy preterm infants during the first 2 months of life. This study showed that plasma levels were markedly elevated for a long time in the infants with respiratory distress. We speculate that plasma ET-1 may be a specific marker for pulmonary endothelium injury in infants with respiratory distress.