Neonatal Intensive Care Unit, Children's and Youth Clinic, Akershus University Hospital, N-1478 Nordbyhagen, Norway.
Pediatr Res. 2010 Jun;67(6):656-9. doi: 10.1203/PDR.0b013e3181dcedc0.
Neonatal jaundice is usually treated with phototherapy that converts bilirubin to more polar stereoisomers. These should theoretically be less able to cross the blood-brain barrier. The rates of photoisomer formation and concentrations accumulating in the circulation may have a bearing on the risk of kernicterus. The purpose of this study was to determine the rate of appearance of the major 4Z, 15E photoisomer of bilirubin during the early stages of phototherapy. Twenty jaundiced neonates were treated with phototherapy, and blood samples were drawn before and at approximately 15, 30, 60, and 120 min (10 infants) or at approximately 15, 60, 120, and 240 min (10 infants) after beginning phototherapy. Blood samples were analyzed for total serum bilirubin (TSB) and the 4Z, 15E photoisomer of bilirubin. Significant (p<0.0001) formation of the 4Z, 15E photoisomer was detectable within 15 min. The change in TSB from time 0 was insignificant at 120 min but reached significance at 240 min (p<0.001). The 4Z, 15E bilirubin constituted up to 20-25% of TSB at 2 h and may not have peaked by 4 h. Further studies are needed to determine whether this early shift in balance between bilirubin isomers with different polarities may impact the risk of bilirubin encephalopathy even before TSB starts to fall.
新生儿黄疸通常采用光疗治疗，该疗法将胆红素转化为更具极性的立体异构体。理论上，这些异构体更不易穿过血脑屏障。光异构体形成的速度和在循环中积累的浓度可能与核黄疸的风险有关。本研究旨在确定光疗早期主要的 4Z,15E 胆红素光异构体出现的速度。20 例黄疸新生儿接受光疗，在光疗开始前和大约 15、30、60 和 120 分钟（10 例婴儿）或大约 15、60、120 和 240 分钟（10 例婴儿）时抽取血样。分析血总胆红素（TSB）和胆红素的 4Z,15E 光异构体。在 15 分钟内即可检测到 4Z,15E 光异构体的明显形成（p<0.0001）。从时间 0 开始，TSB 的变化在 120 分钟时无显著差异，但在 240 分钟时达到显著水平（p<0.001）。4Z,15E 胆红素在 2 小时内占 TSB 的 20-25%，4 小时时可能尚未达到峰值。需要进一步研究以确定这种胆红素异构体之间极性差异的早期平衡变化是否会影响胆红素脑病的风险，甚至在 TSB 开始下降之前。
