Evaluation of Serum Endothelin-1 (ET-1) and Nitric Oxide (NO) Levels in Unconjugated Hyperbilirubinemic Neonates

Abstract

Background: Neonatal hyperbilirubinemia is the most common cause of admission in NICU. Phototherapy is the golden standerd therapy long time ago, which shows efficacy and safety but its side effects should be studied in depth. Both endotheline 1 (ET-1) and nitric Oxide (NO) are potent vasoconstrictor and vasodilator respectively and they are affected by phototherapy. Objectives: This study aimed to investigate the impact of phototherapy on the level of ET-1 and NO in fullterm and preterm as well as studying their effect on hemodynamic stability in treated newborns. Subjects and Methods: This study included 120 newborn infants who were classified into two groups. 60 patients (30 term infants and 30 preterm infants 30 weeks) with unconjugated hyperbilirubinemia indicated for phototherapy and not indicated for exchange transfusion and the onset of jaundice from 2nd to 4th day. In addition, to 60 apparently healthy newborns as control group with matched age, sex, weight and gestational age. Results: There was significant increase in both endothelin-1 and nitric oxide in both fullterm and preterm groups after phototherapy. For fullterm and preterm groups, ET-1 levels significantly increased after 12 hour and 24 hour phototherapy (p-value = 0.048 and 0.013 respectively) for fullterm (p-value = 0.046 and 0.028 respectively) for preterm. Nitric oxide levels among fullterm and preterm groups significantly increased after 12 hour and 24 hour phototherapy (p-value = 0.042 and 0.012 respectively) for fullterm (p value =0.048 and 0.012 respectively) for preterm. The means heart rate changes among fullterm and preterm groups were significantly increased. However, mean arterial blood pressure among full term and preterm groups was significantly decrease after 24 hours of phototherapy. There was a positive correlation between serum levels of ET-1 and NO and heart rate after phototherapy among term and preterm neonats. A negative correlation was found between mean BP and serum levels of NO and a positive correlation between serum levels of ET-1 and mean BP after phototherapy among term and preterm neonates. Conclusion: There was a significant increase in both endothelin-1 and nitric oxide in both full term and preterm groups after treatment with photo-therapy. In addition, a significant increase in mean heart rate and a significant decrease in mean blood pressure among preterm and fullterm groups before and after phototherapy and before phototherapy versus controls.