Breast Milk Constituents and the Development of Breast Milk Jaundice in Neonates: A Systematic Review

Development and Evaluation of Ontogeny Functions of the Major UDP-Glucuronosyltransferase Enzymes to Underwrite Physiologically Based Pharmacokinetic Modeling in Pediatric Populations

Uridine 5'-diphospho-glucuronosyltransferases (UGTs) demonstrate variable expression in the pediatric population. Thus, understanding of age-dependent maturation of UGTs is critical for accurate pediatric pharmacokinetics (PK) prediction of drugs that are susceptible for glucuronidation. Ontogeny functions of major UGTs have been previously developed and reported. However, those ontogeny functions are based on in vitro data (i.e., enzyme abundance, in vitro substrate activity, and so on) and therefore, may not translate to in vivo maturation of UGTs in the clinical setting. This report describes meta-analysis of the literature to develop and compare ontogeny functions for 8 primary UGTs (UGT1A1, UGT1A4, UGT1A6, UGT1A9, UGT2B7, UGT2B10, UGT2B15, and UGT2B17) based on published in vitro and in vivo studies. Once integrated with physiologically based pharmacokinetics modeling models, in vivo activity-based ontogeny functions demonstrated somewhat greater prediction accuracy (mean squared error, MSE: 0.05) compared to in vitro activity (MSE: 0.104) and in vitro abundance-based ontogeny functions (MSE: 0.129).

Evaluation of Glucose 6-Phosphate Dehydrogenase, Pyruvate Kinase, and New Generation Inflammation Biomarkers in Prolonged Neonatal Jaundice

Background and Objectives: To evaluate the clinical findings of glucose 6-phosphate dehydrogenase (G6PD) and pyruvate kinase (PK) deficiency in prolonged jaundice and to determine whether the systemic immune inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR) can be used in the diagnosis of neonatal prolonged jaundice. Materials and Methods: Among full-term neonates with hyperbilirubinemia who were admitted to Medicine Hospital between January 2019 and January 2024 with the complaint of jaundice, 167 infants with a serum bilirubin level above 10 mg/dL, whose jaundice persisted after the 10th day, were included in this study. Results: G6PD activity was negatively correlated with NLR, SII, age, and hematocrit (Hct). There was a weak negative correlation between G6PD and NLR and a moderate negative correlation between G6PD activity and SII when adjusted for age and Hct. PK activity showed no significant correlation with G6PD, NLR, PLR, SII, age, and Hct. A linear relationship was observed between G6PD activity and SII and NLR. Conclusions: NLR and SII can be easily calculated in the evaluation of prolonged jaundice in G6PD deficiency has a considerable advantage. NLR and SII levels may contribute by preventing further tests for prolonged jaundice and regulating its treatment. It may be useful to form an opinion in emergencies and in early diagnostic period.

Bilirubin Levels in Infancy and Their Associations with Body Weight, Levels of Iron-Related Parameters and Steroid Hormone Levels

It is assumed that bilirubin is hormonally regulated and influences weight development by preventing weight gain. However, studies in healthy infants are limited. The present study established reference values for bilirubin and investigated whether bilirubin levels are significantly associated with body weight, levels of ferritin and transferrin as well as steroid hormone levels in a study population of three- and six-month-old healthy infants. Data from a total of 411 study visits from the LIFE Child study (Leipzig, Germany) were analyzed. Associations were examined using linear regression analyses. Besides laboratory parameters, anthropometric data were gathered. We found statistically significant associations between body weight and bilirubin levels. In girls, we observed additional associations between bilirubin levels and both ferritin and transferrin concentrations at three months of age. At six months, steroid hormone levels were significantly associated with concentrations of total and indirect bilirubin, with effects differing by sex. Our study thus confirms associations already reported from animal studies and studies in adult populations. Furthermore, we showed that these associations already exist in the first year of life, are influenced by sex and age and, further, depend on the bilirubin type. Our results provide reference values for bilirubin and assist, therefore, in interpreting bilirubin levels in infancy.

Prolonged Jaundice in a Premature Breastfed Infant With Gilbert's Syndrome

INTRODUCTION

Neonatal jaundice and prematurity pose significant barriers to breastfeeding in the first days of life. There is limited literature exploring the relationship between prolonged jaundice in breastfed infants and Gilbert's (Meulengraght) syndrome. This case study describes the diagnostic and therapeutic challenges associated with Gilbert's syndrome in a late preterm breastfed infant born in Germany.

MAIN ISSUE

In this case report, an infant born to a primipara woman presented at 3 weeks postpartum to an International Board Certified Lactation Consultant. The initial assessment revealed a late preterm infant with inadequate weight gain and jaundice. The dyad received breastfeeding support and eventually achieved adequate weight gain; however, the infant's jaundice persisted.

MANAGEMENT

The consulting midwife suggested that the persistent jaundice was "breastmilk jaundice" and recommended temporarily interrupting breastfeeding. Due to a suspected family history of Gilbert's Syndrome, the dyad was referred, instead, to a pediatric gastroenterologist. Pathologic liver disease was excluded, and genetic testing confirmed Gilbert's Syndrome. At 6 months of age, the dyad was successfully breastfeeding and beginning complementary feeding.

CONCLUSION

Genetic testing for Gilbert's Syndrome should be considered for infants with prolonged jaundice and positive family history. Interruption or cessation of breastfeeding are not evidence-based recommendations, and current guidelines do not support these practices. Lactation professionals play a critical role in the management of breastfeeding for preterm infants with prolonged jaundice and should refer to specialists to rule out pathologic etiologies.

"Light" on Phototherapy-Complications and Strategies for Shortening Its Duration, A Review of the Literature

Neonatal hyperbilirubinemia is an extremely common metabolic complication of the neonatal period which may be associated with bilirubin encephalopathy and even death. Adverse neurological consequences are preventable if a timely diagnosis and treatment are provided. Phototherapy is usually the preferred option to decrease hyperbilirubinemia. Although considered to be safe, evidence in recent years has shown that this treatment may not be free of side effects and short- and long-term unfavorable outcomes. These are usually mild or rare, but should be decreased or avoided if possible. Many useful complementary measures and treatments have been described that could shorten the duration of exposure to phototherapy. However, there is no current unequivocal recommendation to use any of the methods presented in this review. Our review aims to depict the wide range of possible complementary treatments to phototherapy, and to provide the scientific and clinical evidence available regarding their usefulness. It is essential that, while utilizing the full potential of phototherapy to treat hyperbilirubinemia, caregivers are aware of its side effects and possible inherent dangers, and seek ways to minimize the exposure to phototherapy to what is really needed for the newborn. Further studies are needed to clarify the preferred complementary treatments that could reduce the duration of exposure to phototherapy without impairing its effectiveness.