The role of UGT1A1 (c.-3279 T > G) gene polymorphisms in neonatal hyperbilirubinemia susceptibility.

BACKGROUND: Neonatal hyperbilirubinemia (NNH) is a common disease in newborns. This research study aimed to assess the associations between uridine diphospho-glucuronate-glucuronosyltransferase 1A1 (UGT1A1, c.-3279 T > G) polymorphisms and NNH risk. METHODS: We searched PubMed, the Cochrane Library, and the Embase electronic databases. All published eligible studies before July 1, 2019, were searched for this meta-analysis. RESULTS: We identified 7 independent studies including 1560 cases. The data showed that in the general population, compared with the GT + GG vs TT and GG vs TT, c.-3279 T > G (rs4124874) was significantly related to a higher NNH risk (GG vs TT: OR = 1.865, 95% CI: 1.031-3.373, P = 0.039; GT + GG vs TT: OR = 1.331, 95% CI: 1.055-1.679, P = 0.016). Although not statistically significant, the data showed that c.3279 T > G had a tendency to be associated with NNH under the allele model and GG vs GT + TT in the overall population (G vs T: OR = 1.288, 95% CI: 0.982-1.689, P = 0.067; GG vs TT + GT: OR = 1.583, 95% CI: 0.947-2.647, P = 0.080). CONCLUSION: The UGT1A1 gene c.-3279 T > G (rs4124874) polymorphism increased susceptibility to NNH, especially for the comparison of GT + GG vs TT and GG vs TT. In the future, we can use homozygous state of the UGT1A1 gene c.-3279 T > G (rs4124874) polymorphism for the diagnosis and screening of molecular biomarkers in NNH patients.

A Gunn rat model of preterm hyperbilirubinemia.

BACKGROUND: The impact of bilirubin in preterm infants is poorly understood. An animal model would assist in improving understanding. The Gunn rat lacks uridine diphosphate-glucuronylsyl transferase 1 and can be made acutely hyperbilirubinemic by injection of sulfodimethoxine (sulfa), a drug that displaces bilirubin from albumin and thus increases free bilirubin. METHODS: On postnatal day (P) 5, Gunn rats either heterozygous (Nj) or homozygous (jj) for glucuronosyltransferase activity were injected with either saline or sulfa. Behavior and cerebellar weight were measured. RESULTS: Pups did not show any signs of acute bilirubin encephalopathy. Pup weight dropped significantly on P8 only in the jj-sulfa group. Behavior was affected only in the jj-sulfa group. Cerebellar weight was significantly less in the jj-sulfa group. CONCLUSION: The Gunn rat pup model may be a good model to study hyperbilirubinemia in preterm infants.

Modulation of bilirubin neurotoxicity by the Abcb1 transporter in the Ugt1-/- lethal mouse model of neonatal hyperbilirubinemia.

Moderate neonatal jaundice is the most common clinical condition during newborn life. However, a combination of factors may result in acute hyperbilirubinemia, placing infants at risk of developing bilirubin encephalopathy and death by kernicterus. While most risk factors are known, the mechanisms acting to reduce susceptibility to bilirubin neurotoxicity remain unclear. The presence of modifier genes modulating the risk of developing bilirubin-induced brain damage is increasingly being recognised. The Abcb1 and Abcc1 members of the ABC family of transporters have been suggested to have an active role in exporting unconjugated bilirubin from the central nervous system into plasma. However, their role in reducing the risk of developing neurological damage and death during neonatal development is still unknown.To this end, we mated Abcb1a/b-/- and Abcc1-/- strains with Ugt1-/- mice, which develop severe neonatal hyperbilirubinemia. While about 60% of Ugt1-/- mice survived after temporary phototherapy, all Abcb1a/b-/-/Ugt1-/- mice died before postnatal day 21, showing higher cerebellar levels of unconjugated bilirubin. Interestingly, Abcc1 role appeared to be less important.In the cerebellum of Ugt1-/- mice, hyperbilirubinemia induced the expression of Car and Pxr nuclear receptors, known regulators of genes involved in the genotoxic response.We demonstrated a critical role of Abcb1 in protecting the cerebellum from bilirubin toxicity during neonatal development, the most clinically relevant phase for human babies, providing further understanding of the mechanisms regulating bilirubin neurotoxicity in vivo. Pharmacological treatments aimed to increase Abcb1 and Abcc1 expression, could represent a therapeutic option to reduce the risk of bilirubin neurotoxicity.

Developmental influence of unconjugated hyperbilirubinemia and neurobehavioral disorders.

Bilirubin-induced brain injury in the neonatal period has detrimental effects on neurodevelopment that persist into childhood and adulthood, contributing to childhood developmental disorders. Unconjugated bilirubin is a potent antioxidant that may be useful for protecting against oxidative injuries, but it becomes a potent neurotoxin once it crosses the blood brain barrier. Because bilirubin toxicity involves a myriad of pathological mechanisms, can damage most types of brain cells, and affects brain circuits or loops that influence cognition, learning, behavior, sensory, and language, the clinical effects of bilirubin-induced neurotoxicity are likely to be manifold. One possible effect that several experts have identified is bilirubin-induced neurological dysfunction (subtle kernicterus). However, the underlying biological mechanisms or pathways by which subtle kernicterus could lead to developmental disorders has not been elucidated previously. Our aim in this review is to describe a spectrum of developmental disorders that may reflect subtle kernicterus and outline plausible biological mechanisms for this possible association. We review existing evidence that support or refute the association between unconjugated hyperbilirubinemia and developmental disorders, and limitations associated with these studies.

Hyperbilirubinemia-induced pro-angiogenic activity of infantile endothelial progenitor cells.

OBJECTIVES: Bilirubin, a by-product of heme degradation, is suggested to have a role for vascular protection. There is increasing evidence that bilirubin may directly affect the function and secretory activity of endothelial cells. In this study, potential effect of hyperbilirubinemia on biological features of circulation endothelial progenitor cells (cEPCs) isolated from infants was investigated. METHODS: Circulation concentration, differentiation and migratory activity of cEPCs isolated from infants with (n = 111) or without (n = 73) hyperbilirubinemia were analyzed. Then, the potential beneficial effect of conditioned medium of cEPCs from infants with or without hyperbilirubinemia was examined on experimental mouse wounds. RESULTS: Our results revealed significantly higher percentages of cEPCs in infants with hyperbilirubinemia. Cell proliferation, and migratory properties of cEPCs isolated and expanded from infants with hyperbilirubinemia were significantly improved. Also, the conditioned medium of cEPCs from hyperbilirubinemic infants possessed a superior beneficial effect on wound healing, which was associated with increased protein levels of VEGF, IL-10, and Pho-ERK/ERK, and decreased TNF-α in the wound tissues. CONCLUSIONS: Our results showed that hyperbilirubinemia can activate migration, proliferating and angiogenic properties of cEPCs. Hyperbilirubinemia can promote the proangiogenic secretory activity of cEPCs, thereby resulting in enhancement of their regenerative wound healing properties.

Inflammatory signature of cerebellar neurodegeneration during neonatal hyperbilirubinemia in Ugt1 -/- mouse model.

BACKGROUND: Severe hyperbilirubinemia is toxic during central nervous system development. Prolonged and uncontrolled high levels of unconjugated bilirubin lead to bilirubin-induced neurological damage and eventually death by kernicterus. Bilirubin neurotoxicity is characterized by a wide array of neurological deficits, including irreversible abnormalities in motor, sensitive and cognitive functions, due to bilirubin accumulation in the brain. Despite the abundant literature documenting the in vitro and in vivo toxic effects of bilirubin, it is unclear which molecular and cellular events actually characterize bilirubin-induced neurodegeneration in vivo. METHODS: We used a mouse model of neonatal hyperbilirubinemia to temporally and spatially define the response of the developing cerebellum to the bilirubin insult. RESULTS: We showed that the exposure of developing cerebellum to sustained bilirubin levels induces the activation of oxidative stress, ER stress and inflammatory markers at the early stages of the disease onset. In particular, we identified TNFα and NFKß as key mediators of bilirubin-induced inflammatory response. Moreover, we reported that M1 type microglia is increasingly activated during disease progression. Failure to counteract this overwhelming stress condition resulted in the induction of the apoptotic pathway and the generation of the glial scar. Finally, bilirubin induced the autophagy pathway in the stages preceding death of the animals. CONCLUSIONS: This study demonstrates that inflammation is a key contributor to bilirubin damage that cooperates with ER stress in the onset of neurotoxicity. Pharmacological modulation of the inflammatory pathway may be a potential intervention target to ameliorate neonatal lethality in Ugt1 -/- mice.

Reduced Myelination and Increased Glia Reactivity Resulting from Severe Neonatal Hyperbilirubinemia.

Bilirubin-induced neurologic dysfunction (BIND) and kernicterus has been used to describe moderate to severe neurologic dysfunction observed in children exposed to excessive levels of total serum bilirubin (TSB) during the neonatal period. Here we use a new mouse model that targets deletion of the Ugt1 locus and the Ugt1a1 gene in liver to promote hyperbilirubinemia-induced seizures and central nervous system toxicity. The accumulation of TSB in these mice leads to diffuse yellow coloration of brain tissue and a marked cerebellar hypoplasia that we characterize as kernicterus. Histologic studies of brain tissue demonstrate that the onset of severe neonatal hyperbilirubinemia, characterized by seizures, leads to alterations in myelination and glia reactivity. Kernicterus presents as axonopathy with myelination deficits at different brain regions, including pons, medulla oblongata, and cerebellum. The excessive accumulation of TSB in the early neonatal period (5 days after birth) promotes activation of the myelin basic protein (Mbp) gene with an accelerated loss of MBP that correlates with a lack of myelin sheath formation. These changes were accompanied by increased astroglial and microglial reactivity, possibly as a response to myelination injury. Interestingly, cerebellum was the area most affected, with greater myelination impairment and glia burden, and showing a marked loss of Purkinje cells and reduced arborization of the remaining ones. Thus, kernicterus in this model displays not only axonal damage but also myelination deficits and glial activation in different brain regions that are usually related to the neurologic sequelae observed after severe hyperbilirubinemia.

Association between the Specific UGT1A1 Promoter Sequence Variant (c-3279T>G) and Unconjugated Neonatal Hyperbilirubinemia.

We investigated the association between c-3279T>G and unconjugated neonatal hyperbilirubinemia. In all, 141 neonates were recruited; 63 had hyperbilirubinemia necessitating treatment, and 78 with bilirubin < 7 mg/dl served as the control group. The frequency of occurrence of c-3279T > G allele was significantly higher in the hyperbilirubinemic (49.2%) than in the control group (25.6%). The homozygous (p = 0.001, OR = 17.7 and CI = 3.9-79.3) rather than the heterozygous state (p = 0.3, OR = 0.7 and CI = 0.3-1.6) was associated with hyperbilirubinemia. Among the hyperbilirubinemic group, comparison between the three genotypes, homozygous mutation, heterozygous mutation and the normal allele, revealed that the former was associated with significantly higher mean peak total serum bilirubin [mean ± standard deviation (SD): 33.7 ± 8.2, 26.9 ± 2.8 and 21± 2.7, respectively, p-value = 0.0001], higher bilirubin/albumin ratio (p = 0.000) and a longer duration of hospital stay (p = 0.001). Homozygous c-3279T > G mutation represents an important risk factor for the development of neonatal hyperbilirubinemia.

[Glucose-6-phosphate dehydrogenase deficiency in children: a case report]. / Deficiencia de glucosa 6 fosfato deshidrogenasa en niños: caso clínico.

INTRODUCTION: Glucose-6-phosphate dehydrogenase deficiency (G6PD deficiency) is the most common red blood cell (RBC) enzyme disorder. The decrease as well as the absence of the enzyme increase RBC vulnerability to oxidative stress caused by exposure to certain medications or intake of fava beans. Among the most common clinical manifestations of this condition, acute hemolysis, chronic hemolysis, neonatal hyperbilirubinemia, and an asymptomatic form are observed. OBJECTIVE: To analyze the case of a child who presented hemolytic crisis due to favism. CASE REPORT: A 2 year and 7 month old boy with a history of hyperbilirubinemia during the newborn period with no apparent cause, no family history of hemolytic anemia or parental consanguinity. He presented a prolonged neonatal jaundice and severe anemia requiring RBC transfusion. An intake of fava beans 48 h prior to onset of symptoms was reported. G6PD qualitative determination was compatible with this enzyme deficiency. CONCLUSION: G6PD deficiency can be highly variable in its clinical presentation, so it is necessary to keep it in mind during the diagnosis of hemolytic anemia at any age.

Cooperating G6PD mutations associated with severe neonatal hyperbilirubinemia and cholestasis.

We report a novel glucose-6-phosphate dehydrogenase (G6PD) mutation, which we propose to name G6PD Cincinnati (c.1037A > T, p.N346I), found in combination with G6PD Gastonia (c.637G > T, p.V213L) in an infant who presented with neonatal cholestasis. The G6PD Cincinnati mutation results in a non-conservative amino acid substitution at the tetramer interface disturbing its formation, as seen by native gel electrophoresis and immunoblotting. G6PD Gastonia disrupts dimerization of the enzyme and by itself causes chronic non-spherocytic hemolytic anemia. The G6PD Cincinnati mutation may have aggravated the clinical picture of G6PD Gastonia with the result of severe perinatal hemolysis causing cholestasis and associated liver injury.

Neuroprotection of taurine against bilirubin-induced elevation of apoptosis and intracellular free calcium ion in vivo.

Previous work has shown that taurine protected neurons against unconjugated bilirubin (UCB)-induced neurotoxicity by preventing cell apoptosis and maintaining intracellular Ca²âº homeostasis in primary neuron culture. This study investigates the neurotoxicity of hyperbilirubinemia and neuroprotection of taurine in a clinically relevant murine model in vivo. A hyperbilirubinemia baby mice model was established by intraperitoneal injection with UCB. After 24 h, the neural apoptotic level, transcriptional activity of caspase-3, and iCa²âº concentration were detected. It was found that UCB injection significantly increased both intracellular free Ca²âº concentrations and the activities of proapoptosis protease caspase-3, which is related to the elevation of neural apoptosis level. When baby mice were pretreated with 7.5 or 15 mg/kg body weight (bw) taurine for 4 h and then exposed to UCB, apoptotic death was significantly attenuated through down-regulation of activity of caspase-3 and i[Ca²âº] in the brain. From these observations, it was concluded that taurine limits bilirubin-induced neural damage by inhibiting iCa²âº overload as well as decreasing activation of proapoptotic proteases caspase-3. This study might contribute to the development of taurine as a broad-spectrum agent for preventing and/or treating neural damage in neonatal jaundice.

Hyperbilirubinemic stain: location and extent in dental tissues.

OBJECTIVE: The purpose of the present manuscript is to describe the location and extent of hyperbilirubinemic stain in a primary molar of a 3-year-old who was diagnosed with cystic fibrosis shortly after birth, subsequently developed liver disease and hyperbilirubinemia, and received a liver transplant at age 10-months. STUDY DESIGN: Clinical and histological assessments were performed to evaluate the location and extent of hyperbilirubinemic stain in an extracted primary molar. RESULTS: The clinical image, and macroscopic and microscopic histological examinations of a primary molar showed hyperbilirubinemic staining of enamel and of the coronal dentin that developed between birth and when the liver transplant took place, irregular dentin tubules, and an irregular cementum-dentinal junction. CONCLUSIONS: The findings of the present manuscript indicate that hyperbilirubinemc staining of primary teeth affects dental hard tissues at the time of their calcification, and the clinical picture of the stain may be related to stained enamel and/or dentin, and underlying stained dentin visible through translucent unstained enamel.

Characteristics of bilirubin photochemical changes under green light-emitting diodes in humans compared with animal species.

Phototherapy using light-emitting diodes (LEDs) centered on the green spectrum, which has a high cyclobilirubin production rate, was as effective as that centered on the blue spectrum for neonatal hyperbilirubinemia. There are no reports of species differences in bilirubin photochemical changes in this spectrum, and the characteristics of bilirubin photochemical changes in humans must be elucidated to proceed with the development of new light sources that include these spectra. This report describes the characteristic photochemical kinetics of bilirubin under green-spectrum LEDs in human, rat, rabbit, dog, pig, sheep, bovine and chicken serum albumin and rhesus monkey serum. These albumin-bilirubin complex solutions were irradiated by green LEDs, and the time-course changes in bilirubin photoisomers were measured by high-performance liquid chromatography. The cyclobilirubin production rates in humans, pigs, and monkeys were significantly higher than those in other species. The rate constant of (EZ)-cyclobilirubin production from (EZ)-bilirubin 'k' was significantly higher in humans and monkeys than in other species. In conclusion, bilirubin photochemical kinetics under green spectrum LEDs in humans were characterized by a high cyclobilirubin production rate at a low substrate concentration. The bilirubin photochemical kinetics in monkeys were similar to those in humans.

High levels of pathological jaundice in the first 24 hours and neonatal hyperbilirubinaemia in an epidemiological cohort study on the Thailand-Myanmar border.

Population risks for neonatal hyperbilirubinaemia (NH) vary. Knowledge of local risks permits interventions that may reduce the proportion becoming severe. Between January 2015 and May 2016, in a resource-limited setting on the Thailand-Myanmar border, neonates from 28 weeks' gestation were enrolled into a prospective birth cohort. Each neonate had total serum bilirubin measurements: scheduled (24, 48, 72 and 144 hours of life) and clinically indicated; and weekly follow up until 1 month of age. Risk factors for developing NH were evaluated using Cox proportional hazard mixed model. Of 1710 neonates, 22% (376) developed NH (83% preterm, 19% term). All neonates born <35 weeks, four in five born 35-37 weeks, and three in twenty born ≥38 weeks had NH, giving an overall incidence of 249 per 1000 livebirths [95%CI 225, 403]. Mortality from acute bilirubin encephalopathy was 10% (2/20) amongst the 5.3% (20/376) who reached the severe NH threshold. One-quarter (26.3%) of NH occurred within 24 hours. NH onset varied with gestational age: at a median [IQR] 24 hours [24, 30] for neonates born 37 weeks or prematurely vs 59 hours [48, 84] for neonates born ≥38 weeks. Risk factors for NH in the first week of life independent of gestational age were: neonatal G6PD deficiency, birth bruising, Sgaw Karen ethnicity, primigravidae, pre-eclampsia, and prolonged rupture of membranes. The genetic impact of G6PD deficiency on NH was partially interpreted by using the florescent spot test and further genotyping work is in progress. The risk of NH in Sgaw Karen refugees may be overlooked internationally as they are most likely regarded as Burmese in countries of resettlement. Given high levels of pathological jaundice in the first 24 hours and overall high NH burden, guidelines changes were implemented including preventive PT for all neonates <35 weeks and for those 35-37 weeks with risk factors.

Predictive value of bile duct dimensions measured by ultrasound in neonates presenting with cholestasis.

OBJECTIVES: : The significance of extrahepatic bile duct dilatation on ultrasound examination in jaundiced infants is often uncertain. We wished to clarify the diagnostic and prognostic significance of the present finding in neonatal conjugated hyperbilirubinaemia. PATIENTS AND METHODS: : We retrospectively enrolled all of the infants younger than 3 months with extrahepatic biliary dilatation > or =1.2 mm (nonfasting ultrasound) who presented during the study period. We reviewed clinical, radiological, and laboratory data to determine mode of presentation, diagnosis, interventions, and long-term outcome. RESULTS: Seventy-six infants (41 male) were identified, all of whom were referred with conjugated hyperbilirubinaemia. Median gestational age was 39 weeks (range 24-42 weeks). Inspissated bile was the most common diagnostic category, whereas congenital choledochal malformation was the diagnosis made in 13% infants. Dilatation was an incidental finding in 9% of the infants. Seventeen percent of infants had required either surgical or radiological intervention by the time of follow-up. Overall, 41% infants had spontaneous resolution of bile duct dilatation, including 8% who had "grown into" an unchanged duct size rather than involution of dilatation. The median size of bile duct at presentation for those who required intervention was 4.7 versus 2 mm for the remainder (P < 0.001). Of those who resolved spontaneously, the median size of duct at presentation was 1.8 mm. CONCLUSIONS: : Bile duct dilatation <3 mm (nonfasting ultrasound) with neonatal cholestasis is unlikely to be of significance whereas >4 mm is likely to be associated with choledochal malformation or need for intervention. The intermediate group is likely to be associated with inspissated bile syndrome following resolution of which innocent biliary dilatation may persist.

Congenital lupus erythematosus presenting at birth with widespread erosions, pancytopenia, and subsequent hepatobiliary disease.

Neonatal lupus erythematosus is an uncommon disease caused by transplacental passage of maternal anti-Ro (SS-A), anti-LA (SS-B), or anti-U1RNP antibodies. Cutaneous findings of neonatal lupus are variable, but annular, erythematous plaques occurring within a few weeks of birth are most typical. Cutaneous lesions of congenital onset lupus erythematosus can differ from that of neonatal lupus erythematosus, presenting with atrophy or scarring, and less commonly, erosions. We report an unusual case of congenital lupus erythematosus presenting at birth with widespread erosions, pancytopenia, and subsequent hepatobiliary disease.

A firm plaque on the back of a newborn.

We report a case of subcutaneous fat necrosis of the newborn (SCFN), a rare disorder in term or post-term neonates. Although it is often associated with hematological abnormalities such as anemia and hypercalcemia, SCFN in this patient presented with hyperbilirubinemia. The course of SCFN is generally benign and self-limiting, though may be associated with complications secondary to hypercalcemia.

Association between uridin diphosphate glucuronosylotransferase 1A1 (UGT1A1) gene polymorphism and neonatal hyperbilirubinemia.

OBJECTIVE: To assess the prevalence of UGT1A1*28 and UGT1A1*60 polymorphisms of UGT1A1 gene and their association with hyperbilirubinemia. STUDY DESIGN: The study was performed at a single centre - at the Department of Obstetrics of the Medical University of Gdansk in Poland. DNA was isolated from Guthrie cards of 171 infants. Only full term newborns (gestational age 38-42 weeks) were included in the study. Fluorescent molecular probes were used for UGT1A1 promoter variation analysis. The presence of UGT1A1*28 polymorphism was detected with a dual-probe system, and UGT1A1*60 with a SimpleProbe™. RESULT: Homozygous UGT1A1*28 and UGT1A1*60 genotypes were detected in 14.6% and 20.5% of the newborns, respectively. Homozygous (G/G) genotypes of UGT1A1*60 polymorphism were found in all of the UGT1A1*28 (i.e. (TA)7/(TA)7) homozygotes. More than 80% (55/66) of the children with "wild" type UGT1A1*28 genotype (where no polymorphism was detected) (i.e. (TA)6/(TA)6) carried the "wild" (T/T) genotype of UGT1A1*60 as well. The UGT1A1*28 polymorphism was detected more often among neonates with elevated bilirubin. Hyperbilirubinemia was diagnosed more frequently in boys. CONCLUSION: Polymorphisms of the UGT1A1 gene frequently co-exist in neonates. The presence of UGT1A1*28 polymorphism and male gender seem to predispose to neonatal hyperbilirubinemia.

Enduring controversies in the management of hyperbilirubinemia in preterm neonates.

Although it is generally believed that preterm infants are at greater risk for the development of bilirubin-associated brain damage than term infants, quantification of the magnitude of this risk has proven elusive, as has a consensus among experts on the level of total serum bilirubin at which therapy should be initiated. Two large randomized studies have been performed that shed some light on the risk hyperbilirubinemia poses for preterm neonates and both studies are reviewed. Additional study is needed to further clarify the risk posed by hyperbilirubinemia in premature neonates and to frame guidelines for phototherapy and exchange transfusion that are more evidence-based.

Glucose-6-phosphate dehydrogenase deficiency and severe neonatal hyperbilirubinemia: a complexity of interactions between genes and environment.

Glucose-6-phosphate dehydrogenase deficiency is a commonly occurring genetic condition, likely to be encountered today in virtually any corner of the globe. Sudden episodes of hemolysis associated with the condition may result in exponential increases in serum total bilirubin concentrations to levels at which bilirubin-induced neurologic damage may occur. The hyperbilirubinemia is the result of complex interactions between genes and environment. Neonatal screening programs coupled with parental and medical caretaker education may be successful in limiting the severity of disease.