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Jaundice affects almost all neonates in their first days of life and is caused by the accumulation of bilirubin. Although the core biochemistry of bilirubin metabolism is well understood, it is not clear why some neonates experience more severe jaundice and require treatment with phototherapy. Here, we present the first genome-wide association study of neonatal jaundice to date in nearly 30,000 parent-offspring trios from Norway (cases ≈ 2000). The alternate allele of a common missense variant affecting the sequence of UGT1A4 reduces the susceptibility to jaundice five-fold, which replicated in separate cohorts of neonates of African American and European ancestries. eQTL colocalization analyses indicate that the association may be driven by regulation of UGT1A1 in the intestines, but not in the liver. Our results reveal marked differences in the genetic variants involved in neonatal jaundice compared to those regulating bilirubin levels in adults, suggesting distinct genetic mechanisms for the same biological pathways., (© 2024. The Author(s).)

When liver or intestinal function is impaired, bilirubin accumulates in the body and leads to neonatal jaundice. However, the potential negative effects caused by excessive accumulation of bilirubin such as developmental immunotoxicity and neurotoxicity remain unclear. We used a zebrafish model to establish bilirubin-induced jaundice symptoms and evaluated the toxic effects of bilirubin in aquatic organisms. Firstly, our results suggested that bilirubin exposure markedly decreased the survival rate, induced the developmental toxicity and increased the yellow pigment deposited in the zebrafish tail. Meanwhile, the number of macrophages and neutrophils was substantially reduced in a concentration-dependent manner. Besides, the antioxidant enzyme activities were greatly elevated while the inflammatory genes were significantly decreased after bilirubin exposure. Secondly, transcriptome analysis identified 708 genes were differentially expressed after bilirubin exposure, which animal organ morphogenesis, chemical synaptic transmission, and MAPK / mTOR signaling pathways were significantly enriched. Thirdly, bilirubin exposure leads to a significant decrease in the motility of zebrafish, including a dose-dependent decrease in the travelled distance, movement time, and average velocity. Moreover, the innate immune genes and apoptosis-related genes such as TLR4, NF-κB p65, STAT3 and p53 were elevated at a concentration of 10 μg/mL of bilirubin. Finally, our results further revealed that the anti-inflammatory and neuroprotective minocycline could partially rescue the bilirubin-induced neurobehavioral disorders in zebrafish embryos. In conclusion, our study explored the bilirubin-induced immunotoxicity and neurotoxicity in aquatic organisms, which will provide a theoretical basis for the treatment of neonatal jaundice in clinical practice., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

Early identification of neonatal jaundice (NJ) appears to be essential to avoid bilirubin encephalopathy and neurological sequelae. The interaction between gut microbiota and metabolites plays an important role in early life. It is unclear whether the composition of the gut microbiota and metabolites can be used as an early indicator of NJ or to aid clinical decision-making. This study involved a total of 196 neonates and conducted two rounds of "discovery-validation" research on the gut microbiome-metabolome. It utilized methods of machine learning, causal inference, and clinical prediction model evaluation to assess the significance of gut microbiota and metabolites in classifying neonatal jaundice (NJ), as well as the potential causal relationships between corresponding clinical variables and NJ. In the discovery stage, NJ-associated gut microbiota, network modules, and metabolite composition were identified by gut microbiome-metabolome association analysis. The NJ-associated gut microbiota was closely related to bile acid metabolites. By Lasso machine learning assessment, we found that the gut bacteria were associated with abnormal bile acid metabolism. The machine learning-causal inference approach revealed that gut bacteria affected serum total bilirubin and NJ by influencing bile acid metabolism. NJ-associated gut bile acids are potential biomarkers of NJ, and clinical prediction models constructed based on these biomarkers have some clinical effects and the model may be used for disease risk prediction. In the validation stage, it was found that intestinal metabolites can predict NJ, and the machine learning-causal inference approach revealed that bile acid metabolites affected NJ itself by affecting the total bilirubin content. Intestinal bile acid metabolites are potential biomarkers of NJ. By applying machine learning-causal inference methods to gut microbiome-metabolome association studies, we found NJ-associated intestinal bacteria and their network modules and bile acid metabolite composition. The important role of intestinal bacteria and bile acid metabolites in NJ was determined, which can predict the risk of NJ.

Breast milk is crucial in the development of late-onset breast milk jaundice (BMJ), possibly due to the composition of breast milk and the lactating mother’s diet. To explore the possible nutritional pathogenesis of late-onset BMJ, we investigated the lactation diet and collected breast milk by following the 42-day postpartum mother−infants pairs in Beijing and a total of 94 pairs were enrolled. The macronutrient content of breast milk was measured, and the epidermal growth factor (EGF) content in breast milk was determined by ELISA. Data on in-hospital and out-of-hospital breastfeeding, infant growth, jaundice-related vaccination, and puerperium diet were collected. The BMJ group received the second dose of hepatitis B vaccine later than the control group, and the difference was statistically significant (p < 0.001). The EGF concentration in breast milk was lower in the BMJ group than in the control group (p = 0.03). When EGF increased by 1 ng/mL, the transcutaneous bilirubin (TcB) value decreased by 0.33 ng/mL and 0.27 ng/mL before and after the adjustment, respectively. A 1 g increase in oil intake led to a 0.38 ng/mL increase in EGF concentration before the adjustment. With a 1 g increase in oil intake, the TcB value decreased by 0.27 ng/mL before the adjustment, and with a 1 g increase in soybean and soybean product intake, the TcB value decreased by 0.34 ng/mL after the adjustment. Collectively, EGF in breast milk may inhibit the occurrence of late-onset BMJ, and the dietary intake of oil in lactating mothers may affect the level of EGF in breast milk, thus affecting the occurrence of late-onset BMJ. Finally, dietary oil intake may be a protective factor for the occurrence of late-onset BMJ by increasing EGF levels in breast milk.

Background: Severe neonatal jaundice resulting from elevated levels of unconjugated bilirubin in the blood induces dramatic neurological impairment. Central oxidative stress and an inflammatory response have been associated with the pathophysiological mechanism. Cells forming the blood-brain barrier and the choroidal blood-CSF barrier are the first CNS cells exposed to increased plasma levels of unconjugated bilirubin. These barriers are key regulators of brain homeostasis and require active oxidative metabolism to fulfill their protective functions. The choroid plexus-CSF system is involved in neuroinflammatory processes. In this paper, we address the impact of neonatal hyperbilirubinemia on some aspects of brain barriers. We describe physiological changes in the neurovascular network, blood-brain/CSF barriers integrities, and CSF cytokine levels during the postnatal period in normobilirubinemic animals, and analyze these parameters in parallel in Gunn rats that are deficient in bilirubin catabolism and develop postnatal hyperbilirubinemia., Methods: Gunn rats bearing a mutation in UGT1a genes were used. The neurovascular network was analyzed by immunofluorescence stereomicroscopy. The integrity of the barriers was evaluated by [ 14 C]-sucrose permeability measurement. CSF cytokine levels were measured by multiplex immunoassay. The choroid plexus-CSF system response to an inflammatory challenge was assessed by enumerating CSF leukocytes., Results: In normobilirubinemic animals, the neurovascular network expands postnatally and displays stage-specific regional variations in its complexity. Network expansion is not affected by hyperbilirubinemia. Permeability of the blood-brain and blood-CSF barriers to sucrose decreases between one- and 9-day-old animals, and does not differ between normobilirubinemic and hyperbilirubinemic rats. Cytokine profiles differ between CSF and plasma in all 1-, 9-, and 18-day-old animals. The CSF cytokine profile in 1-day-old animals is markedly different from that established in older animals. Hyperbilirubinemia perturbs these cytokine profiles only to a very limited extent, and reduces CSF immune cell infiltration triggered by systemic exposure to a bacterial lipopeptide., Conclusion: The data highlight developmental specificities of the blood-brain barrier organization and of CSF cytokine content. They also indicate that a direct effect of bilirubin on the vascular system organization, brain barriers morphological integrity, and inflammatory response of the choroid plexus-CSF system is not involved in the alteration of brain functions induced by severe neonatal jaundice., (© 2022. The Author(s).)

Aims: We investigated the relationship between total serum bilirubin (TSB) and carboxyhemoglobin (COHb) in term neonates with detected and treated hemolysis within a particular time frame with the aim of augmenting the case for early diagnosis and prevention of morbidity in hemolysis. Materials and Methods: The study group comprised term newborns who were above the 95th percentile for TSB, underwent intravenous immunoglobulin (IVIG) or applied total exchange transfusion due to hemolysis. Newborns without hemolysis who were above the 95th TSB percentile and required phototherapy comprised the control group. Results: At a cutoff COHb value of 2.2%, 80.8% sensitivity, 95.5% specificity, 18.1 likelihood ratio, positive predictive value of 94.7%, and negative predictive value of 83.2% were identified. Conclusion: We found that COHb is a sensitive and specific method for detecting hemolysis, and it can be used in the early diagnosis of hemolytic diseases causing early and severe hyperbilirubinemia.

Introduction: Exclusive breastfeeding for the initial six months of life is crucial and it is recommended . Breast milk jaundice is an innocuous condition that occurs in some healthy, breastfed infants. However, the potential dangers of jaundice in the neonate such as bilirubin induced neuronal pathology, mandates a better understanding of the pathophysiology of breast milk jaundice and the impact of breastfeeding during jaundice. In this context , advice on continued breastfeeding must consider both the benefits of breastfeeding and the possible disadvantages of the jaundice., Methods: Reviewing literature and integrating relevant information facilitated the appraisal of this important topic. This article reviewed neonatal jaundice, the entry of bilirubin into the immature brain and how breastfeeding may impact jaundice in the neonate., Results: While some substances in breast milk may be responsible for jaundice on the one hand, there is an irrefutable spectrum of advantages conferred by continued breastfeeding, on the other. As the breastfed infant benefits from fewer infections, enhanced organ and physiological barrier maturity, as well as the prospect of genetic modification of certain diseases, these useful actions could also reduce risks of early jaundice and its complications., Discussion: An exciting field for further research, holistic integration of knowledge clarifies both the overall advantages of breastfeeding and wisdom of its continued counsel. In fact, breast milk jaundice may reflect a holistic expression of tissue protection and enhanced neonatal survival.

Background: Transcutaneous bilirubin (TcB) measurement is widely used in term babies. But its effectiveness till debated in preterm infants. So, our objective was to pool data to see the accuracy of transcutaneous bilirubinometry in preterm infants., Method: MEDLINE, Embase, Cochrane Library database were searched from 2000 to July 2017. The included studies had compared TcB with total serum bilirubin (TSB) in preterm infants before phototherapy and data were presented as correlation coefficients. Data were extracted by two reviewers and checked for accuracy by the third reviewer. The risk bias assessments were done by an assessment quality assessment of diagnostic accuracy studies tool. Pooled correlation coefficient assed after Fisher's z transformation and then converted to r., Results: We included 28 studies; all those studies reported results as correlation coefficients. In combination of both sternal and forehead site measurement, our pooled estimates of r = 0.82 (95% CI: 0.78-0.85) in random effect and r = 0.803 (95% CI: 0.78-0.81) in fixed effect model. For separate sites of measurement of TcB pooled r for forehead and sternum were comparable, r = 0.82 (95% CI: 0.78-0.85), and pooled correlation coefficient for the two devices JM103 and Bilicheck the estimated pooled r were also comparable (Pooled r = 0.83)., Conclusion: Our study found that TcB measurement is well related with TSB values and can represent a reliable method for evaluating preterm infants with possible hyperbilirubinemia. Our findings support the use of investigated devices at both forehead and sternum sites in preterm infants.

Our objective was to assess the relationship between hyperbilirubinemia with and without kernicterus and metabolic profile at newborn screening. Included were 1,693,658 infants divided into a training or testing subset in a ratio of 3:1. Forty-two metabolites were analyzed using logistic regression (odds ratios (ORs), area under the receiver operating characteristic curve (AUC), 95% confidence intervals (CIs)). Several metabolite patterns remained consistent across gestational age groups for hyperbilirubinemia without kernicterus. Thyroid stimulating hormone (TSH) and C-18:2 were decreased, whereas tyrosine and C-3 were increased in infants across groupings. Increased C-3 was also observed for kernicterus (OR: 3.17; 95% CI: 1.18-8.53). Thirty-one metabolites were associated with hyperbilirubinemia without kernicterus in the training set. Phenylalanine (OR: 1.91; 95% CI: 1.85-1.97), ornithine (OR: 0.76; 95% 0.74-0.77), and isoleucine + leucine (OR: 0.63; 95% CI: 0.61-0.65) were the most strongly associated. This study showed that newborn metabolic function is associated with hyperbilirubinemia with and without kernicterus., (© 2018 The Authors. Clinical and Translational Science published by Wiley Periodicals, Inc. on behalf of the American Society for Clinical Pharmacology and Therapeutics.)

Objective: Neonatal jaundice is a common disease that affects up to 60% of newborns. Gut microbiota mediated the excretion of bilirubin from the human body. However, the relationship between early gut microbiome and development of neonatal jaundice is not fully understood. Here we sought to characterize meconium microbiome of newborns and to clarify its association with risk of neonatal jaundice., Methods: We conducted a nested case-control study with 301 newborns providing meconium samples from 2014 to 2015. The main outcome was the development of neonatal jaundice at 42 day follow-up. 16S rRNA gene sequencing was performed to profile the meconium microbiome. LEfSe was employed to identify different features between control and case groups. Logistic regression was used to estimate the risk effect of early gut microbiome on neonatal jaundice., Results: Logistic regression models suggested that higher ɑ-diversity was significantly associated with lower risk of jaundice in cesarean infants (OR 0.72, 95% CI 0.52-0.98), but not in infants born naturally. Higher relative abundance of Bifidobacterium pseudolongum in newborn meconium was significantly associated with lower risk of jaundice both in cesarean-born infants and in the total subjects (OR 0.24, 95% CI 0.07-0.68; OR 0.55, 95% CI 0.31-0.95, respectively). Spearman's correlations showed that relative abundance of B. pseudolongum was significantly correlated with ɑ-diversity (P < 0.01)., Conclusion: Preventive and treatment methods implying early gut microbiome intervention could be promising for the management of neonatal jaundice.

Background: Although neonates and young infants with cholestasis are commonly treated with either phenobarbital or ursodeoxycholic acid (ursodiol), there is no evidence that phenobarbital is effective for this indication. Our objective was to compare the effectiveness of ursodiol and phenobarbital for the treatment of cholestasis in a diverse NICU population., Methods: This is a retrospective cohort study including infants with cholestasis who were admitted to a Level IV NICU between January 2010 and December 2015. Drug courses of phenobarbital and ursodiol were identified within the medical record, and medical, demographic, and drug information were extracted. The primary outcome was reduction in direct bilirubin., Results: Sixty-eight infants provided a total of 112 courses of drug therapy for comparison. Diverse medical diagnoses were captured in the patient cohort. Ursodiol was significantly more effective in reducing direct bilirubin than was phenobarbital (- 1.89 vs + 0.76 mg/dL; - 33.33 vs + 13.0 umol/L, p-value 0.03), even after controlling for baseline cholestasis severity, intrauterine growth restriction status, and lipid lowering therapy (- 2.16 vs + 0.27 mg/dl; - 36.94 vs + 4.62 umol/L, p-value 0.03). There was no improvement in direct bilirubin in the majority of infants treated with phenobarbital., Conclusions: Phenobarbital, as compared to ursodiol, has limited efficacy for the reduction of direct bilirubin in neonates and young infants with cholestasis. Given new data regarding the potential neurotoxicity of phenobarbital in the developing brain, providers may choose to avoid phenobarbital in the treatment of cholestasis in infants.

Introduction: Due to a peculiar age-dependent increased susceptibility, neonatal cholestasis affects the liver of approximately 1 in every 2500 term infants. A high index of suspicion is the key to an early diagnosis, and to implement timely, often life-saving treatments. Even when specific treatment is not available or curative, prompt medical management and optimization of nutrition are of paramount importance to survival and avoidance of complications. Areas covered: The present article will prominently focus on a series of newer diagnostic and therapeutic options of cholestasis in neonates and infants blended with consolidated established paradigms. The overview of strategies for the management reported here is based on a systematic literature search published in English using accessible databases (PubMed, MEDLINE) with the keywords biliary atresia, choleretics and neonatal cholestasis. References lists from retrieved articles were also reviewed. Expert commentary: A large number of uncommon and rare hepatobiliary disorders may present with cholestasis during the neonatal and infantile period. Potentially life-saving disease-specific pharmacological and surgical therapeutic approaches are currently available. Advances in hepatobiliary transport mechanisms have started clarifying fundamental aspects of inherited and acquired cholestasis, laying the foundation for the development of possibly more effective specific therapies.

Aim: Jaundice may cause auditory toxicity (auditory neuropathy and hearing loss). However, total serum bilirubin (TSB) does not discriminate neonates at risk for auditory toxicity. We compared TSB, bilirubin:albumin molar ratio (BAMR), and unbound bilirubin for their association with auditory toxicity in neonates with severe jaundice (TSB ≥342μmol/L, or that met exchange transfusion)., Method: Neonates greater or equal to 34 weeks gestational age with severe jaundice during the first 2 postnatal weeks were eligible for prospective cohort study, unless they had craniofacial malformations, chromosomal disorders, toxoplasmosis, other infections, rubella, cytomegalovirus, herpes simplex infections, surgery, or family history of congenital deafness., Results: Twenty-eight out of 100 neonates (mean gestational age 37.4wks; 59 males, 41 females) had auditory toxicity. Peak unbound bilirubin, but not peak TSB and BAMR, was associated with auditory toxicity (p<0.05) in neonates with severe (TSB <427.5μmol/L) and extreme hyperbilirubinemia (TSB ≥427.5μmol/L). Area under the receiver operating characteristic curve for unbound bilirubin (0.78) was significantly greater (p=0.03) than TSB (0.54) among neonates with severe but not extreme hyperbilirubinemia., Interpretation: Unbound bilirubin is more strongly associated with auditory toxicity than TSB and/or BAMR in greater or equal to 34 weeks gestational age neonates with severe jaundice. Unbound bilirubin is a better predictor than TSB in neonates with severe hyperbilirubinemia., (© 2016 Mac Keith Press.)

Phototherapy has been widely used in treating neonatal jaundice, but detailed metabonomic profiles of neonatal jaundice patients and response to phototherapy have not been characterized. Our aim was to depict the serum metabolic characteristics of neonatal jaundice patients relative to controls and changes in response to phototherapy. A (1) H nuclear magnetic resonance (NMR)-based metabonomic approach was employed to study the metabolic profiling of serum from healthy infants (n = 25) and from infants with neonatal jaundice (n = 30) pre- and postphototherapy. The acquired data were processed by multivariate principal component analysis (PCA) and orthogonal partial least-squares-discriminant analysis (OPLS-DA). The PLS-DA and OPLS-DA model identified nine metabolites capable of distinguishing patients from controls. In addition, 28 metabolites such as β-glucose, α-glucose, valine, and pyruvate changed in response to phototherapy. This study offers useful information on metabolic disorders in neonatal jaundice patients and the effects of phototherapy on lipids, amino acid, and energy metabolism., (© 2016 The Authors. Clinical and Translational Science published by Wiley Periodicals, Inc. on behalf of American Society for Clinical Pharmacology and Therapeutics.)

Phototherapy is the main treatment for neonatal hyperbilirubinemia. In acute treatment of extreme hyperbilirubinemia, intensive phototherapy may have a role in 'detoxifying' the bilirubin molecule to more polar photoisomers, which should be less prone to crossing the blood-brain barrier, providing a 'brain-sparing' effect. This article reviews the biology of bilirubin isomers. Although there is evidence supporting the lower toxicity of bilirubin photoisomers, there are studies showing the opposite. There are methodologic weaknesses in most studies and better-designed experiments are needed. In an infant acutely threatened by bilirubin-induced brain damage, intensified phototherapy should be used expediently and aggressively., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Background: A novel filtered-sunlight phototherapy (FSPT) device has been demonstrated to be safe and efficacious for treating infants with neonatal jaundice in resource-constrained tropical settings. We set out to provide baseline data for evaluating the clinical impact of this device in a referral pediatric hospital., Methods: We reviewed the medical records of infants admitted for neonatal hyperbilirubinemia in an inner-city Children's Hospital in Lagos, between January 2012 and December 2014 to determine the pattern, treatment and outcomes during the pre-intervention period. Factors associated with adverse outcomes were identified through multivariable logistic regression., Results: Of the 5,229 neonatal admissions over the period, a total of 1,153 (22.1%) were admitted for neonatal hyperbilirubinemia. Complete records for 1,118 infants were available for analysis. The incidence of acute bilirubin encephalopathy (ABE) and exchange transfusion (ET) were 17.0% (95% CI: 14.9%-19.3%) and 31.5% (95% CI: 28.8%-34.3%) respectively. A total of 61 (5.5%, 95% CI: 4.3%-6.9%) of the jaundiced infants died. Weight on admission, peak total serum bilirubin (TSB), sepsis and exposure to hemolytic products were predictive of ABE, while age on admission, peak TSB, ABO incompatibility and ABE were predictive of ET. Rhesus incompatibility, asphyxia, exposure to hemolytic substances and ABE were associated with elevated mortality risk, while ET was a protective factor. Lack of routine irradiance monitoring and steady energy supply were frequent challenges for conventional blue-light phototherapy., Conclusions: Severe hyperbilirubinemia is associated with high rates of ABE and ET in this setting, and remains a significant contributor to neonatal admissions and mortality. To be impactful, FSPT, complemented with improved diagnostic facilities, should effectively curtail jaundice-related adverse outcomes in this and comparable settings.

Objective: To evaluate the effects of baby massage on transcutaneous bilirubin levels and stool frequency of healthy term newborns., Methods: This Pilot study was conducted on 50 healthy newborns in Valiasr Hospital of IKHC. The infants were randomly allocated to two treatment (massage) and control group. The massage group received massage therapy (according to Touch Therapy) for four days from the first day postnatal while the control group received routine care. Main variable studied were transcutaneous bilirubin level (TCB) and stool frequency which were compared in two groups., Results: There were 50 newborns in the study 25 in each group (50%). There was a significant difference in the TCB levels between two groups (p=0.000) with those in the massage group having lower bilirubin levels. As for the stool frequency there was a significant difference in two groups on the first day showing more defecation in the control group (p=0.042) which on the consequent days was not significant and the frequencies were almost similar., Conclusion: Massage group had a lower transcutaneous billirubin levels compared to the control group, thus, these pilot results indicate that massaging the newborns can be accompanied by a lower bilirubin level in the healthy term newborn., (Copyright © 2015 Elsevier Inc. All rights reserved.)

In the first days of life, low grade jaundice is essentially universal. The source of the elevated bilirubin level giving rise to "physiological jaundice of the newborn" is only partly known. We hypothesized that it is, at least in part, the result of active and specific hemolysis involving a physiological mechanism to lower the high fetal hematocrit, appropriate for the relatively low oxygen environment in utero, to a lower level appropriate for the state of oxygen abundance after birth. We tested this by quantifying end tidal carbon monoxide (ETCO) as a marker of the rate of heme metabolism to bilirubin. We found that ETCO values of 20 neonates and children with known hemolytic disorders were higher than 20 age-matched healthy controls (p<0.0001), indicating that this instrumentation recognizes hemolysis in neonates and children. We also found that ETCO reference intervals were indeed higher in healthy neonates during the first three days after birth (5th to 95th percentile reference range, 1.4 to 1.7ppm) than after 1month of age (all ≤1.0ppm, p<0.0001). These results suggest to us that hemolysis is physiological during the first days after birth. The cellular and molecular mechanisms responsible for transient hemolysis after birth are topics of current investigation., (Copyright © 2014 Elsevier Inc. All rights reserved.)

The present study was designed to investigate the effect of Agaricus brasiliensis extract (ABE) on phenylhydrazine-induced neonatal jaundice in rats. Administration of ABE dose-dependently reduced the elevated bilirubin level induced by phenylhydrazine. It can be somewhat supported from the results of in vitro bilirubin degradation experiment. ABE treatment also reduced the total antioxidant status (TAOS), cascade O2(-)/SOD, level of NF-κB protein, and adrenomedullin (AM). Overall, the results of this study demonstrated that Agaricus brasiliensis extract may be beneficial to reducing bilirubin level without causing hepatotoxicity in neonatal jaundice.

The blood-brain barrier (BBB) is a complex and dynamic structure that plays a key role in central nervous system (CNS) homeostasis. It strictly regulates the entrance of molecules into the brain parenchyma and prevents the access of neurotoxins and pathogens while promoting the efflux of several molecules. The brain microvascular endothelial cells are the anatomical basis of the BBB, which has unique characteristics such as the elaborate junctional complexes that nearly obliterate the intercellular space as well as the presence of influx and efflux transporters. Endothelial cells establish important interactions with glial cells, neurons, and perivascular pericytes as well as with the acellular components of the basement membrane, which together constitute the neurovascular unit. BBB disruption has been reported in a wide range of CNS pathologies, with an emerging role in the onset and disease progression. Accordingly, recent studies revealed vascular dysfunction in neonatal jaundice, a common pathology in the early neonatal period affecting 1/10 children presenting values of total bilirubin>17 mg/dL (291 μM). Here we summarize the clinical aspects of moderate to severe neonatal jaundice and provide a comprehensive review of the literature regarding bilirubin-induced neurotoxicity from a vascular-centered approach. The collected evidence place endothelial dysfunction and pericyte demise as key players in the disruption of CNS homeostasis, mainly in cases of lasting hyperbilirubinemia, thus pointing to novel targets to prevent neurological dysfunction due to severe neonatal jaundice., (Copyright © 2015 IMSS. Published by Elsevier Inc. All rights reserved.)

Fetal distress represents a pathophysiological condition in which oxygen is not available to the fetus in sufficient quantities. In cases of glucose 6-phosphate dehydrogenase (G6PD) deficiency, under conditions of oxidative stress, the residual G6PD and complimentary antioxidant mechanisms may become insufficient to neutralize the large amounts of ROS and to prevent severe hemolysis. Alteration in the oxidant-antioxidant profile is also known to occur in neonatal jaundice. The study group included 22 neonates presented with fetal distress during labor and 24 neonates with no evidence of fetal distress (control group). Umbilical cord blood samples were taken immediately after delivery, and the following blood tests were carried out after birth and at discharge from the hospital: erythrocyte count, total bilirubin, G6PD activity, and parameters presenting oxidative status [thiobarbituric acid reactive substances (TBARS), NO, O2 (-), H2O2, SOD, CAT, O2 (-)/SOD, and H2O2/CAT]. There were no significant differences in TBARS and NO values among neonates with or without fetal distress. However, the values of O2 (-), H2O2, SOD, O2 (-)/SOD, and H2O2/CAT among neonates born after fetal distress were significantly higher than in neonates without fetal distress (p < 0.01). In neonates with fetal distress, the total number of RBCs at delivery was significantly lower, accompanied with higher bilirubin content. Also neonates with fetal distress had lower activity of G6PD and lower CAT activity. Higher values of oxidative stress parameters in newborns delivered after fetal distress do not indicate strictly what occurred first-oxidative stress or basic lower G6PD activity.

The accuracy of transcutaneous bilirubin meters has been assessed in newborns from various ethnic backgrounds. However, there are limited data on Greek newborns. Our study examined the accuracy of transcutaneous bilirubin measurements in clinically jaundiced healthy-term Greek newborns, using total serum bilirubin as the reference standard, in order to re-evaluate our local guidelines about neonatal jaundice. Clinically jaundiced newborns requiring total serum bilirubin level estimation were recruited prospectively. 368 pairs of total serum bilirubin/transcutaneous bilirubin measurements were taken in 222 newborns, using a direct spectrophotometric device and the BiliCheck device, respectively. The level of agreement between the obtained transcutaneous bilirubin and total serum bilirubin values was assessed. Our data were analysed using the Stata/SE 12.0 (StataCorp LP, USA) statistical programme. The mean (± SD) TSB was 225.4 ± 25.4 μmol/l and the mean (± SD) TcB was 237.9 ± 21.0 μmol/l. The correlation between the values was poor (Pearson's correlation coefficient 0.439; Lin's concordance coefficient 0.377 [95% CI 0.301 to 0.453]; P<0.001). The Bland-Altman analysis demonstrated that transcutaneous bilirubin measurements tended to overestimate the total serum bilirubin value (mean difference 12.5 ± 24.9 μmol/l), with wide 95% limits of agreement (-36.2 μmol/l to 61.3 μmol/l). Transcutaneous bilirubin values did not correlate well with total serum bilirubin values, being often imprecise in predicting the actual total serum bilirubin levels. This permits us to continue estimating total serum bilirubin in clinically jaundiced newborns according to our local guidelines, in order to safely decide the appropriate care plan.

Data comparing the cutaneous side effects of light emitting diode (LED) phototherapy (LP) and conventional phototherapy (CP) devices in jaundiced newborn infants are very limited. We investigated the incidence and extent of skin eruptions caused by different phototherapy devices in preterm infants who are more prone to neonatal jaundice. This prospective, randomized controlled trial was conducted in the neonatal intensive care unit (NICU) of Hacettepe University Ihsan Dogramaci Childrens' Hospital in Ankara, Turkey. Preterm infants without skin lesions before and requiring phototherapy in the first week of life were included in the study. The infants were randomly assigned to receive CP or LP and were monitored closely for skin eruptions during phototherapy. Fifty-eight infants were included in the study: 25 (43.1%) received CP while 33 (56.9%) received LP. The duration of phototherapy was similar in the two groups (30.4 ± 9.6 hours and 31.8 ± 15.6 hours, respectively). Baseline and control bilirubin levels were similar for the two groups (p = 0.101 and p = 0.105, respectively). The frequency of skin eruptions was 36% in the CP group and 33% in the LP group (p = 0.83). The skin eruptions were macules in 13 (22.4%), papules in 5 (8.6%), and maculopapular rashes in 2 (3.4%) infants.There were no differences in the incidence and extent of skin eruptions in preterm infants who received CP or LP., (© 2013 Wiley Periodicals, Inc.)

The introductory summarises the classical path of heme degradation and classification of jaundice. Subsequently, a description of neonatal types of jaundice is given, known as Crigler Najjar, Gilberts, DubinJohnson and Rotor syndromes, emphasising the explanation of the molecular mechanisms of these metabolic disorders. Special attention is given to a recently discovered molecular mechanism of the Rotor syndrome. The mechanism is based on the inability of the liver to retrospectively uptake the conjugated bilirubin fraction primarily excreted into the blood, not bile. A reduced ability of the liver to uptake the conjugated bilirubin contributes to the development of hyperbilirubinemia in common disorders of the liver and bile ducts and to the toxicity of xenobiotics and drugs using transport proteins for conjugated bilirubin.

Background: Maternal milk plays an important role in the development of late-onset breast milk jaundice (BMJ), possibly due to the unique characteristics of breast milk. The aim of this study was to investigate whether there is a relation between cytokine concentrations in the milk of nursing mothers and BMJ., Methods: Breast milk samples were collected from breast-feeding mothers of healthy full-term neonates, 40 with BMJ and 40 without jaundice. Milk samples were taken between the second and the fourth postpartum week. The concentrations of interleukin (IL)-1 β, IL-6, IL-8, IL-10, and tumor necrosis factor-α were measured by flow cytometric bead array., Results: There were significant differences between the study groups in terms of IL-1 β concentrations (P= 0.013). Not statistically significant but similar trends were also seen for IL-10 (P= 0.067) and tumor necrosis factor-α (P= 0.053) concentrations. However, no significant differences were noted in IL-6 (P= 0.174) and IL-8 (P= 0.285) concentrations., Conclusions: IL-1 β concentration seems to be increased in milk of mothers whose infants had BMJ. Although the effect of these cytokines on BMJ is unknown, it may cause prolonged jaundice via hepatic uptake, hepatic excretion, conjugation and intestinal absorption., (© 2012 The Authors. Pediatrics International © 2012 Japan Pediatric Society.)

Unlabelled: In humanized UDP glucuronosyltransferase-1 (hUGT1) mice that express the entire UGT1 locus, the maternal hepatic UGT1A genes are dramatically induced 12-14 days after conception. Steroid induction of the UGT1A1 gene indicates that xenobiotic sensors, such as the pregnane X receptor (PXR) and constitutive androstane receptor (CAR), may underlie the induction process. In contrast, neonatal hUGT1 mice display severe hyperbilirubinemia, with limited expression of the UGT1A genes. This study identifies PXR as both a positive and negative regulator of the UGT1A1 gene. Pregnancy hormones, in particular the glucocorticoids, target PXR as a positive regulator of human glucuronidation. Employing reverse genetics, where PXR has been genetically deleted, hUGT1/Pxr(-/-) mice show limited induction of the liver UGT1A genes during pregnancy, whereas the exact opposite occurs in newborn mice. Neonatal hUGT1 mice show delayed expression of hepatic UGT1A1 and are severely hyperbilirubinemic. However, in hUGT1/Pxr(-/-) mice, hyperbilirubinemia is greatly reduced due to induction of hepatic UGT1A1. Thus, PXR serves to repress UGT1A1 gene expression during development. Transcriptional silencing of the UGT1A1 gene was relieved in neonatal hUGT1 hepatocytes through interruption of PXR by small interfering RNA., Conclusion: PXR is a key regulator of pregnancy induced glucuronidation capacity in addition to modulating the severity of neonatal jaundice., (Copyright © 2012 American Association for the Study of Liver Diseases.)

The differentiation between biliary atresia (BA) and idiopathic neonatal hepatitis (INH) is challenging with many histological overlaps especially in the first weeks of life. This study aimed to investigate the role of immunohistochemical staining of CK7, Ki67, CD34, and vimentin in addition to other clinicopathological features in the differentiation between BA and INH. Cases included 30 infants with BA and 30 infants with INH. The diagnosis was based on clinical, laboratory, and liver biopsy examination. Female gender and elevated serum gamma glutamyle transferase were in favor of BA. Portal tract changes, such as bile ductular proliferation documented by CK7, Ki67 immunostaining and angiogenesis documented by CD34 immunostaining, favored the diagnosis of BA. Copper associated protein was positive in 70% of BA cases, but not detected in INH cases. Parenchymatous changes, such as giant cell transformation and positive iron deposition and Kupffer cell proliferation documented by vimentin immunostaining, favored the diagnosis of INH.CK7, Ki67, CD34, and vimentin are helpful adjuvant immunostaining in the differentiation between BA and INH., (© 2012 The Authors. APMIS © 2012 APMIS.)

OBJECTIVE. To evaluate the effectiveness of transcutaneous bilirubin (TcB) measurement in predicting risk for neonatal hyperbilirubinemia in outpatients. DESIGN. Subjects were infants ≤8 days old seen in an outpatient clinic. Infants discharged with high-risk (HR) or high-intermediate risk (HIR) total serum bilirubin (TSB) values and jaundiced infants were recruited. TSB and TcB (BiliChek) levels were plotted on an hour-specific nomogram to determine risk for hyperbilirubinemia. RESULTS. A total of 79 infants provided 87 sets of TcB and TsB values. Mean bias and standard deviation between TcB and TsB was 1.5 ± 2.1 mg/dL for outpatients, compared with 2.7 ± 1.3 mg/dL for inpatients. The sensitivity and specificity of HR or HIR TcB for predicting an HR or HIR TSB were 87% and 58%, respectively. Of 9 infants readmitted for phototherapy, 1 had a low-risk TcB and high-risk TSB. CONCLUSIONS. TcB screening in the outpatient environment may not be safe and efficient.

Neonatal jaundice usually occurs in the transitional period after birth, presenting as an elevation of circulating bilirubin. Bilirubin neurotoxicity can occur if the levels of bilirubin become excessive (hyperbilirubinemia). This pathologic phenotype of newborn jaundice can develop because of excessive bilirubin production or impaired conjugation, with the risk for developing bilirubin-induced neurologic dysfunction, depending on the degree of the resultant bilirubin load. The plasma bilirubin level thus can be used to assess an infant's risk for developing bilirubin neurotoxicity relative to an infant's age in hours. Because all infants have an impaired conjugation ability, infants at greatest risk are those who have increased bilirubin production rates, because of hemolysis, for example. Therefore, developing potential preventive strategies as well as noninvasive technologies to treat and to identify infants with increased bilirubin production rates, respectively, are tantamount to reducing the incidence of bilirubin-induced neurologic dysfunction., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Extreme neonatal jaundice occurs infrequently but carries a high risk of permanent sequelae (kernicterus) when it does. Rapid therapeutic intervention has the potential to reduce this risk in some infants. Several case reports of infants with acute intermediate to advanced bilirubin encephalopathy shows that reversal may be possible. Phototherapy can be instituted at the flip of a switch, whereas other therapeutic measures necessarily involve delays. Therefore, high-intensity phototherapy must be regarded as an emergency measure in infants presenting with extreme jaundice and even more so in the presence of neurological symptoms. The principal and well-described effect of phototherapy involves conversion of bilirubin IXα (z, z) to more polar isomers, which are excreted in bile and urine. When care is taken to maximize the spectral power of phototherapy lights, and whenever possible with measures added to reduce the enterohepatic circulation of bilirubin, very rapid reductions in total serum bilirubin levels are possible. A hypothesis has been advanced that conversion of bilirubin to more polar photoisomers, which can reach relative concentrations of 20%-25% of total serum bilirubin within 1-2 hours, might have a direct neuroprotective effect. This theory posits that because polar molecules generally require a transporter to cross the blood-brain barrier, bilirubin photoisomers should be less prone to enter the brain. Although this theory has some support in in vitro toxicity studies, the evidence is controversial. Until further experimental support can be gained, photoconversion of bilirubin does not constitute a viable argument against instituting further measures against bilirubin neurotoxicity, such as intravenous immune globulin (when indicated) and exchange transfusion. Conversely, neither is the state of evidence an argument against immediate and effective phototherapy in the medical emergency of extreme neonatal jaundice., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Objective: Transcutaneous bilirubin (TcB) has the potential to reduce serum bilirubin sampling. During a recent survey on the use of TcB in postnatal units in the Republic of Ireland, we identified that only 58% of the 19 units were using TcB and that only two devices were in use, the BiliChek® and JM 103®. We aimed to evaluate and compare these two devices in a regional postnatal unit., Methods: To evaluate and compare the accuracy of the BiliChek® and JM 103®, we studied simultaneous TcB and total serum bilirubin (TSB) measurements from a population of jaundiced term and near term infants. We evaluated each device with regard to correlation with TSB and potential to safely reduce serum bilirubin testing., Results: Both TcB devices strongly correlated with TSB (r = 0.88 for BiliChek® and r = 0.70 for JM 103®. The BiliChek® and JM 103® were accurate up to cut-off values of 200 μmol/L and 180 μmol/L, respectively. Using Bhutani's nomogram, 100% sensitivity was achieved using the 75th percentile for BiliChek® and the 40th percentile for JM 103®., Conclusion: Both TcB devices correlated closely with moderately increased TSB levels and are suitable screening tools to identify jaundiced infants that require a serum bilirubin, with upper limit cut-off values. Both devices reduced the need for TSB levels. We found the BiliChek® slightly more accurate than the JM 103® for our study population. TcB however, is not in widespread use.

In breastfeeding newborns who are otherwise healthy, the mechanism of prolonged jaundice remains unclear. The aim of this study was to investigate relations between prolonged jaundice and oxidative parameters in breast milk. Full-term, otherwise healthy newborns with jaundice lasting more than 2 weeks were enrolled prospectively in the study. As a control group, newborns in the same age group but without prolonged jaundice were selected. All newborns in the study were exclusively breastfed. In the newborns with prolonged jaundice, investigations of the etiology of the jaundice included complete blood count, peripheral blood smear, blood typing, direct Coombs test, measurement of serum levels of total and direct bilirubin, tests for liver and thyroid function (TSH, free T4, total T4), urine culture and measurement of urine reducing substances, and determination of glucose 6 phosphate dehydrogenase enzyme levels. Breast milk was collected from the mothers of the newborns in both groups. The antioxidant status of the breast milk was assessed via determination of total antioxidant capacity (TAC). Oxidative stress was also assessed in breast milk by measurement of total oxidation status (TOS) and calculation of the oxidative stress index (OSI). The prolonged jaundice group differed significantly from the control group in terms of mean TAC and OSI (p < 0.001), but not in terms of TOS. In conclusion, in the breast milk of mothers of newborns with prolonged jaundice, oxidative stress was found to be increased, and protective antioxidant capacity was found to be decreased.

Unlabelled: Alpha(1)-antitrypsin is the most abundant circulating protease inhibitor. The severe Z deficiency allele (Glu342Lys) causes the protein to undergo a conformational transition and form ordered polymers that are retained within hepatocytes. This causes neonatal hepatitis, cirrhosis, and hepatocellular carcinoma. We have developed a conformation-specific monoclonal antibody (2C1) that recognizes the pathological polymers formed by alpha(1)-antitrypsin. This antibody was used to characterize the Z variant and a novel shutter domain mutant (His334Asp; alpha(1)-antitrypsin King's) identified in a 6-week-old boy who presented with prolonged jaundice. His334Asp alpha(1)-antitrypsin rapidly forms polymers that accumulate within the endoplasmic reticulum and show delayed secretion when compared to the wild-type M alpha(1)-antitrypsin. The 2C1 antibody recognizes polymers formed by Z and His334Asp alpha(1)-antitrypsin despite the mutations directing their effects on different parts of the protein. This antibody also recognized polymers formed by the Siiyama (Ser53Phe) and Brescia (Gly225Arg) mutants, which also mediate their effects on the shutter region of alpha(1)-antitrypsin., Conclusion: Z and shutter domain mutants of alpha(1)-antitrypsin form polymers with a shared epitope and so are likely to have a similar structure.

Hyperbilirubinemia remains a common condition in neonates. The constitutive androstane receptor (CAR) is an orphan nuclear receptor that has been shown to participate in the activation of the uridine diphosphate-5'-glucuronosyltransferase 1A1 (UGT1A1) gene, which plays an important role in bilirubin clearance. Oncostatin M (OSM), a member of the IL-6 family, is involved in the maturation of fetal hepatocytes. We have demonstrated that low OSM levels are a potential indicator of neonatal jaundice and the need for phototherapy. In this study we examined the effects of OSM on CAR-mediated signaling to investigate its potential role in neonatal jaundice via the CAR-UGT1A1 pathway. We observed that OSM positively augmented the CAR and UGT1A1 expressions and CAR-mediated signaling in vivo and in vitro, through cross talk between the nuclear CAR receptor and the plasma membrane OSM receptor, via the MAPK cascade. These data suggest that OSM might play a role in bilirubin metabolism via the CAR-UGT1A1 pathway.

Neonatal jaundice is a medical condition which occurs in newborns as a result of an imbalance between the production and elimination of bilirubin. Excess bilirubin in the blood stream diffuses into the surrounding tissue leading to a yellowing of the skin. The extra-vascular bilirubin act as interfering signal that limits the estimation of serum bilirubin from reflectance spectrum of human skin. This is particularly an issue for neonates who are being subjected to phototherapy (a common treatment for neonatal jaundice). Unfortunately, analytical models developed to study the light transport in human skin do not consider the effects of extra-vascular bilirubin (and other absorbing chromophores). A biomedical signal processing method that estimates serum bilirubin in presence of confounding signals such as melanin and extra-vascular bilirubin concentrations is presented. The new system model and nonlinear solver have been successful in estimating the serum bilirubin concentration on simulated spectral databases within an average error of 15%.

Severe unconjugated hyperbilirubinemia, seen mainly in neonates, may cause kernicterus and death. Conventional treatment for severe unconjugated hyperbilirubinemia consists of phototherapy and exchange transfusion. Phototherapy, however, has several known disadvantages while exchange transfusion is associated with a significant morbidity, and even mortality. These harmful effects indicate the need to develop alternative pharmacological treatment strategies for unconjugated hyperbilirubinemia. Generally, these strategies aim to decrease the plasma concentration of unconjugated bilirubin (UCB) by inhibiting production, stimulating hepatic clearance, or interrupting the enterohepatic circulation of the pigment. To be considered for routine clinical use, an alternative treatment strategy should be less invasive and at least as effective and safe as phototherapy. Several pharmacological therapies such as metalloporhyrins, clofibrate, bile salts, laxatives and bilirubin oxidase may meet these criteria in the future, but none of them has yet been evaluated sufficiently to allow routine application. This review aims to discuss the state of the art and future perspectives in pharmacological treatment of neonatal jaundice.

Our aim was to study the usefulness of jaundice visual assessment combined with skin bilirubin determination in 517 healthy newborns. Yellowness assessment was made and babies were included in three different bilirubin classes. Skin bilirubin and total serum bilirubin were determined within 10 minutes from the visual assessment. This latter led to underestimation of serum bilirubin in 16.7-40.4% and overestimation in 4.9-35.7% of newborns. Skin bilirubin measurement after the visual assessment decreased the risk of underestimation to 0-9.2% and the risk of overestimation to 2.1-11.1%. The majority of visual assessment errors were performed in the more lighted hours of the morning (75%), while the smallest number (39%) occurred during the afternoon. Skin bilirubin measurement significantly corrected these diagnostic errors (p < 0.001, p < 0.02) without differences during the day. Clinical estimate is unreliable for evaluating the need for serum bilirubin assay. Using the addition of skin bilirubin determination is a more advisable approach.

It has remained unclear whether the amount of fecal fat excreted in the stool and stool production influences the severity of neonatal jaundice. We determined the relationship between stool production, fecal fat excretion and jaundice in healthy breast-fed (BF) or formula-fed (FF) (near-)term neonates. From postnatal day 1-4, we quantitatively collected stools from 27 FF and 33 BF infants in daily fractions. Stool production and fecal fat contents were related to unconjugated bilirubin (UCB) levels, as determined by transcutaneous bilirubinometry (TcB). Bilirubin concentrations and stool production did not differ between FF and BF neonates during the study period. Neonatal bilirubin levels were not inversely correlated with stool production. FF and BF infants had similar fecal fat excretion rates. The stool production of FF infants was profoundly lower in the present study than in a 1985 study by De Carvalho et al. [J Pediatr (1985) 107:786-790]. We conclude that increased jaundice during the first postnatal days in healthy term neonates can no longer be attributed to breast-feeding and speculate that improved absorbability of formulas since 1985 has contributed to similar fat excretion and stool production in FF and BF neonates in 2007.

Objective: To investigate the predictive value of umbilical cord serum (UCS) bilirubin for subsequent jaundice in healthy term newborns., Methods: Five hundred and twenty-three healthy term newborns (275 boys, 248 girls) were selected. The cord blood total serum bilirubin concentration and the serum albumin concentration were determined. All the infants were assessed for jaundice daily by measurement of transcutaneous bilirubin (TCB). When the infant's TCB was >or= 18 within the first 24 h after birth, >or= 21 at 48 h, >or= 25 at or after 72 h, the venous total serum bilirubin (TSB) was determined and treatment against jaundice was applied as needed. The infants were aligned into four groups according to their UCS bilirubin levels, starting from < 30 micromol/L(group 1); >or= 30 micromol/L(group 2); >or= 36 micromol/L(group 3); >or= 42 micromol/L(group 4). The frequency of hyperbilirubinemia and phototherapy (PT) were compared among the four groups. An analysis of UCS bilirubin as a predictor of later development of jaundice was performed. The characteristics of the infants who became jaundiced (jaundiced group) were compared with the normal infants (non-jaundiced group)., Results: A clear correlation between UCS bilirubin level and the development of hyperbilirubinemia was found in all populations of the four groups. Only eight of the 194 infants in group 1 showed a TCB index >or= 25. TSB values > 205 micromol/L but < 257 micromol/L were observed in 2 newborns. None of the infants in this group showed TSB > 257 micromol/L or needed PT. Thirty-two infants in group 2 showed TCB >or= 25, 12 infants had TSB > 205 micromol/L but < 257 micromol/L, 2 infants had TSB > 205 micromol/L and received PT. In group 3, one infant developed hyperbilirubinemia at 48 h after birth and received PT. Thirty-nine infants showed TCB >or= 25, 16 infants TSB > 205 micromol/L but < 257 micromol/L, 2 infants had TSB > 205 micromol/L and also received PT. In group 4, 4 infants showed a range of TSB from 200 to 215 micromol/L at 48 h and received PT. Twenty-two infants showed TCB >or= 25, 17 of them showed TSB > 205 micromol/L but < 257 micromol/L, and 5 of them had TSB > 205 micromol/L and received PT. The frequency of TSB > 205 micromol/L increased from 1.03% in group 1, 5.77% in group 2, 19.75% in group 3 and to 42.5% in group 4. None of the 194 newborns in group 1 needed phototherapy, whereas 0.96%, 3.70% and 22.5% of the newborns in groups 2 - 4, needed PT. The frequency of patients with hyperbilirubinemia or phototherapy increased with increasing UCS bilirubin levels. For the prediction of TCB >or= 25 using a UCS bilirubin cut-off level, such as >or= 35 micromol/L, we found a positive predictive value of 45.68% and sensitivity of 68.27%. It is significant to predict neonatal jaundice by UCS bilirubin levels (P < 0.001). In the jaundiced group (TCB >or= 25) UCS bilirubin levels were significantly higher than those in the non-jaundiced group (t = 10.96, P < 0.001). No significant differences were found in the cord blood serum albumin concentration (t = 2.38, P > 0.05), the gestational age (t = -0.90, P > 0.05), and birthweight (t = 0.10, P > 0.05) between the jaundiced and non-jaundiced groups., Conclusions: UCS bilirubin level is useful in predicting the subsequent jaundice in healthy term infants. The use of UCS bilirubin values may help detect infants at low or high risk for hyperbilirubinemia and minimize an unnecessary prolongation of hospitalization.

Breast-fed infants have higher bilirubin levels than formula-fed infants, possibly because of variations in the composition of the breast milk. The aim of this study was to investigate whether there is a relationship between cytokine levels in the colostrum of nursing mothers and neonatal jaundice (NJ). Breast milk samples were collected from breast-feeding mothers of healthy full-term neonates, 32 with NJ and 29 without jaundice. The concentrations of IL-1beta, IL-6, IL-8, IL-10, and tumor necrosis factor (TNF)-alpha were measured by chemiluminescence enzyme immunometric assays. Mothers of infants with NJ had a higher concentration of IL-1beta in colostrum, compared with those feeding neonates without NJ, and similar trends were seen for IL-6, IL-8, IL-10, and for TNF-alpha. The concentrations of IL-1beta significantly correlated with IL-6, IL-8, IL-10, and TNF-alpha concentrations, but not with serum bilirubin levels of infants with NJ. In conclusion, the concentrations of IL-1beta were increased in colostrum from breast-feeding mothers whose infants had NJ. The correlation between the concentrations of cytokines involved in the function of hepatic uptake and excretory systems and in the enterohepatic circulation of bilirubin provides additional data to the delineation of the cascade of pathophysiological events that can lead to NJ.

Neonatal jaundice, a physiologic condition reflecting the interplay between developmentally modulated changes in bilirubin production and metabolism, affects virtually all newborn infants. Usually, it is an entirely benign process that is resolved at the end of the first week of life without treatment or sequelae. However, in a small percentage of neonates, unconjugated hyperbilirubinemia can pose a neurotoxic risk especially in the presence of aggravating conditions such as a diminished albumin binding capacity and/or affinity, acidosis, displacing drugs and prematurity. Although neuronal cells are considered the main target for unconjugated bilirubin (UCB) toxicity, circulating cells are also affected during neonatal hyperbilirubinemia. Moreover, the UCB ability to cause hemolysis shall further aggravate neonatal jaundice through a vicious circle. In this review, we summarize the most relevant data obtained by our group regarding UCB toxicity and the role of some risk factors for kernicterus. In order to improve the risk assessment of neurotoxicity it is essential to understand the underlying mechanisms of UCB pathophysiology.

Objective: Neonatal jaundice is the result of an imbalance between bilirubin production and elimination, and our objective was to clarify the contribution of an increase in bilirubin production to hyperbilirubinemia in newborns., Methods: We measured the end-tidal carbon monoxide concentration corrected for ambient carbon monoxide concentration in 108 jaundiced newborns (total serum bilirubin level >75th percentile) and 164 control newborns in our well-infant nursery, for the first 4 days after birth., Results: Mean end-tidal carbon monoxide levels decreased in the control infants in the first 4 days but increased in the hyperbilirubinemic group. The differences between the jaundiced and nonjaundiced infants were statistically significant on all days., Conclusions: Before hospital discharge, most infants with bilirubin levels >75th percentile are producing significantly more bilirubin than those with lower bilirubin levels. Because the ability of newborns to conjugate bilirubin is significantly impaired in the first few days, even a small increase in the rate of production can contribute to the development of hyperbilirubinemia. These data suggest that increased heme catabolism is an important mechanism responsible for hyperbilirubinemia in the first 4 days after birth.

A model for brain bilirubin uptake (BBU) predicts that BBU in jaundiced newborns typically depends on the plasma total bilirubin concentration (TBC) and the bilirubin-albumin dissociation rate constant (k1) rather than the unbound bilirubin (Bf). The model's validity was tested by 1) evaluating its requirement that k3>>>k2, where k3 and k2 are the rate constants for BBU and Bf-albumin association, respectively, and 2) determining whether the calculated BBU is

Transcutaneous bilirubin (TcB) has been reported to have a high correlation with serum bilirubin. The objectives of this study were: (1) to compare the accuracy of two transcutaneous bilirubinometer (Minolto AirShields Jaundice Meter, JM103 (JM) and SpectRx, Bilicheck (BC) in estimating total serum bilirubin (TSB) levels; and (2) to assess the predictive ability of transcutaneous bilirubin in relation to specific selected TSB levels. A total of 154 measurements of TcB, using JM and BC, and TSB were recruited from 134 term and near-term infants. Postnatal ages ranged from 19 to 160 hours (x = 64.7, SD = 25.6). TSB levels ranged from 4.5 to 17.5 mg/dl (x = 10.4, SD = 2.5). The correlation coefficients between TcB (JM and BC) and TSB measurements were significant and similar (r 0.80 and 0.82, respectively). The errors of distribution were, for TSB and TcB-JM, the mean difference of 0.7 mg/dl (SD 1.6 mg/dl and 95% confidence interval of the mean (CI) 0.4 and 1.0]; and, for TSB and TcB-BC, the mean difference of -0.6 mg/dl (SD 1.5 mg/dl and 95% CI -0.4 and -0.8). TcB-JM had a tendency to underestimate TSB levels, and TcB-BC had a tendency to overestimate TSB levels. The sensitivity of BC was higher, but specificity was lower, than JM in corresponding to different TSB levels, except at a TSB level of 15 mg/dl when both instruments yielded 100% sensitivity. The accuracy of JM in predicting TSB was higher than BC at all TSB levels. Operating the JM was simple and uncomplicated. It would be suitable for clinical use when a number of personnel perform the measurement.

Objectives: Neonatal jaundice is a greater problem for infants fed breast milk, compared with formula. This study tested the hypotheses that feeding breastfed newborns beta-glucuronidase inhibitors during the first week after birth would increase fecal bilirubin excretion and would reduce jaundice without affecting breastfeeding deleteriously., Methods: Sixty-four breastfed newborns were randomized to 4 groups, ie, control or receiving 6 doses per day (5 mL per dose) of L-aspartic acid, enzymatically hydrolyzed casein (EHC), or whey/casein (W/C) for the first week. L-aspartic acid and EHC inhibit beta-glucuronidase. Transcutaneous bilirubin levels (primary outcome) were measured daily (Jaundice Meter [Minolta/Air Shields, Hatboro, PA] and Bilicheck [Respironics, Pittsburgh, PA]). All stools were collected, and fecal bile pigments, including bilirubin diglucuronide, bilirubin monoglucuronides, and bilirubin, were analyzed with high-performance liquid chromatography. Follow-up assessments included day 7 body weight, day 6/7 prebreastfeeding/postbreastfeeding weights, maternal ratings, and ages at formula introduction and breastfeeding cessation., Results: The groups were comparable at entry. Overall, the L-aspartic acid, EHC, and W/C groups had significantly lower transcutaneous bilirubin levels than did the control group (75.8%, 69.6%, and 69.2%, respectively, of the control mean, 8.53 mg/dL, at the bilirubin peak on day 4). The L-aspartic acid, EHC, and W/C groups had significantly lower transcutaneous bilirubin levels on days 3 to 7. Fecal bile pigment excretion was greatest in the L-aspartic acid group, significantly greater than control values. There were no significant differences in dosages, follow-up measurements, and maternal ratings., Conclusions: Use of minimal aliquots of L-aspartic acid and EHC for beta-glucuronidase inhibition results in increased fecal bilirubin excretion and less jaundice, without disruption of the breastfeeding experience. Decreased jaundice in the W/C group, which lacked a beta-glucuronidase inhibitor, suggests a different mechanism.