Background Hyperbilirubinemia is a condition that affects most infants, but typically self-resolves and is not harmful. However, if bilirubin levels exceed neuroprotective defenses, the compound can cross the blood-brain barrier and have neurotoxic and potentially fatal effects. Treatment of neonatal hyperbilirubinemia with phototherapy is necessary for the prevention of kernicterus. Guidelines for the use of phototherapy in infants born at ≥ 35 weeks’ gestation were published by Bhutani et al. and endorsed by the American Academy of Pediatrics. Consensus-based recommendations for phototherapy treatment and exchange transfusion of premature infants were published in 2012 by Maisels, et al. However, there are no published recommendations for the timing of screening for hyperbilirubinemia in NICU patients. In 2012, the Kapʻiolani Medical Center for Women & Children Neonatology Division implemented internal guidelines for phototherapy with recommendations for the timing of screening serum bilirubin levels, based on the group’s opinion. Five years later, the current study queried whether these guidelines for screening were appropriate. Objective The present study sought to describe current practices of obtaining serum bilirubin levels and the use of phototherapy in the NICU during the first five days of life. It was hypothesized that many bilirubin levels obtained at ≤ 48 hours of life are below published recommended treatment thresholds and are potentially unnecessary. Methods Retrospective chart review was performed on all infants admitted to the NICU at < 24 hours of life, from July 2016-June 2017. Eligible infants were divided into three gestation age groups: ≤ 28, 29-35, and ≥ 36 weeks at birth. Patient demographics, bilirubin levels, and phototherapy treatment were noted. The primary outcome of interest was the percent of serum bilirubin levels obtained during the first 48 hours of life that did not meet phototherapy treatment criteria. Results 931 charts were reviewed. Infants born at ≤ 28, 29-35 and ≥ 36 weeks’ gestation made up 10%, 51% and 39% of the cohort. Overall mortality was 3%, and no exchange transfusions were performed during the study period. At least one serum bilirubin level was obtained for 96% of the patients, but only 55% were treated with phototherapy within the first five days of life. Phototherapy was rarely prescribed on day of life (DOL) 1 (0.7%). By DOL 2, a total of 563 bilirubin levels were obtained, but only 108 infants (19%) were treated with phototherapy. However, one-third of these patients’ bilirubin levels did not meet published criteria for treatment. The timing of phototherapy treatment varied by gestational age. Ninety percent of infants born ≤ 28 weeks’ gestation who received phototherapy were treated starting between DOL 2-3. In contrast, eighty-five percent of infants born ≥ 29 weeks’ gestation who received phototherapy, started on DOL 3-5. Discussion Far more bilirubin levels were obtained than courses of phototherapy prescribed. Given the distinct patterns of phototherapy for infants of varying gestational age, there is ample opportunity to improve resource utilization with targeted recommendations for obtaining screening bilirubin levels in the neonate without early jaundice.

Identification and functional characterization of numerous transport systems at the sinusoidal and canalicular membrane of hepatocytes have significantly expanded our understanding of bilirubin metabolism and contributed to elucidation of molecular basis of hereditary jaundice. Moreover, dysregulation of hepatobiliary transport systems could explain jaundice in many acquired liver disorders. This thesis is focused on the new aspects of bilirubin handling in hepatocytes based on elucidation of the molecular basis of Rotor syndrome. The first study is focused on the antioxidative properties of bilirubin in liver tissue in a model of obstructive cholestasis. In the second part of the thesis we present several novel mutations in ABCC2, the gene associated with Dubin-Johnson syndrome, identified in patients selected for the Rotor locus mapping study. In the key third study concerned with Rotor syndrome we demonstrated that biallelic inactivating mutations causing complete absence of transport proteins OATP1B1 and OATP1B3 result in disruption of hepatic reuptake of bilirubin, which is the molecular basis of Rotor-type jaundice. These results indicate that apart from secretion of conjugated bilirubin into bile, a significant fraction of bilirubin glucuronide is secreted via MRP3 into sinusoidal blood and...

Orientador: Fernando Perazzini Facchini, Sergio Tadeu Martins Marba / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-09T10:38:23Z (GMT). No. of bitstreams: 1 Leite_MariadasGracasdaCunha_D.pdf: 4639567 bytes, checksum: 1396117012228a6590af2c4de8b522c5 (MD5) Previous issue date: 2007 / Resumo: Objetivo: Comparar dosagens transcutâneas de bilirrubina realizadas com o ¿Bilicheck®¿ com as dosagens de bilirrubina total plasmática realizada pelo ¿Bilirrubinômetro Unistat- Leica®¿em neonatos. Métodos: Um total de 200 recém-nascidos foram incluídos no estudo, sendo que cada um teve apenas uma dosagem pelo ¿Bilicheck®¿ , seguida de coleta capilar e dosagem através de espectrofotometria direta pelo ¿Bilirrubinômetro Unistat-Leica®¿. Foram analisadas as correlações e concordâncias entre os métodos e a influência das variáveis: peso de nascimento, raça, idade gestacional, idade pós-natal e uso de fototerapia. Estabelecemos pontos de corte nas dosagens pelo ¿Bilirrubinômetro Unistat-Leica®¿ para avaliarmos a sensibilidade e especificidade do ¿Bilicheck®¿, em níveis de bilirrubina considerados como limites para modificação das terapêuticas preconizadas. Resultados: A correlação linear foi de 0,92 entre o total de pacientes (p=0,0001). A média da diferença entre as dosagens foi de 0,72 (± 1,57) mg/dl, com intervalo de confiança em 95 % de ¿ 2,42 a + 3,86 mg/dl. Dentre as variáveis estudadas, somente a idade pós-natal inferior a 3 dias de vida sofreu interferência na dosagem transcutânea de bilirrubina (p= 0,0030). Considerando a dosagem pelo ¿Bilirrubinômetro Unistat-Leica®¿ como padrão de referência, foram confeccionadas repetidas curvas ROC, sendo o melhor ponto de corte o valor correspondente a 14 mg/dl pelo ¿Bilicheck®¿ com sensibilidade de 88,2%, especificidade de 97,8%, valor preditivo positivo 78,9%, valor preditivo negativo 98,9% e área abaixo da curva de 0,98. Conclusão: A dosagem transcutânea de bilirrubina realizada pelo ¿Bilicheck®¿ pode substituir a dosagem feita pelo ¿Bilirrubinômetro Unistat-Leica®¿ até o valor de 14 mg/dl. Acima deste nível, deve ser considerada apenas como rastreador na seleção de pacientes que devem ser submetidos à dosagem sanguínea / Abstract: Aim: To compare transcutaneous bilirubin m easurement determined by ¿Bilicheck®¿ with capillary serum measurement determined by ¿U nistat-Leica Bilirubinometer¿ in newborns. Methods: A total of 200 newborns were included. For each one, paired measurements (serum, with ¿Unistat-Leica Bilirubinometer¿ and transcutaneous, with ¿Bilicheck®¿ were performed. Their correlation and agreement were analyzed and it was verified the influence of birth weight, race, gestational age, postnat al age and use of phototherapy. We also tried to establish cutoff points in ¿Unistat-Leica Bilirubinometer¿ measurements to access the sensibility and specificity of the ¿Bilicheck®¿ in the critic levels of bilirrubin that are considered for indication of treatments. Results: The linear correlation was 0.92 ( p=0.0001), the average difference between the measurements was 0.72 (± 1.57) mg/dl, with a confidence interval of 95% from -2.42 to +3.86 mg/dl. The only variable that exhi bited a small statistical difference (p=0.003) was postnatal age of less than 3 days. Considering the ¿Bilirubin ometer Unistat-Leica¿ as gold standard, a series of ROC curves were constr ucted revealing that the best cutoff point was at 14 mg/dl with sensitivity of 88.2%, specifi city of 97.8%, positive predictive value of 78.9% and negative predictive value of 98.9% and the area under the curve was 0.98. Conclusion: The ¿Bilicheck®¿ may substitute th e capillary serum measurement until the value of 14 mg/dl. Above this level, it should be considered as a screening test selecting patients that must be submitted to serum measurement / Doutorado / Pediatria / Doutor em Saude da Criança e do Adolescente

Identification and functional characterization of numerous transport systems at the sinusoidal and canalicular membrane of hepatocytes have significantly expanded our understanding of bilirubin metabolism and contributed to elucidation of molecular basis of hereditary jaundice. Moreover, dysregulation of hepatobiliary transport systems could explain jaundice in many acquired liver disorders. This thesis is focused on the new aspects of bilirubin handling in hepatocytes based on elucidation of the molecular basis of Rotor syndrome. The first study is focused on the antioxidative properties of bilirubin in liver tissue in a model of obstructive cholestasis. In the second part of the thesis we present several novel mutations in ABCC2, the gene associated with Dubin-Johnson syndrome, identified in patients selected for the Rotor locus mapping study. In the key third study concerned with Rotor syndrome we demonstrated that biallelic inactivating mutations causing complete absence of transport proteins OATP1B1 and OATP1B3 result in disruption of hepatic reuptake of bilirubin, which is the molecular basis of Rotor-type jaundice. These results indicate that apart from secretion of conjugated bilirubin into bile, a significant fraction of bilirubin glucuronide is secreted via MRP3 into sinusoidal blood and...

Inherited disorders of bilirubin metabolism - hereditary hyperbilirubinemias - are metabolic disorders manifested in early childhood. Unconjugated hyperbilirubinemias result from the defect of the enzyme uridine diphosphoglucuronosyltransferase (UGT1A1). UGT1A1 mediates the conjugation of bilirubin with glucuronid acid in hepatocytes and its elimination to water soluble compound. In the next step of bilirubin degradation the transport of conjugated bilirubin from hepatocyte into the bile occure. It is caused by the ATP dependent transporters ABCC2, ATP1B1 and OATP1B3. Mutations in the genes coding the bilirubin transporters results in conjugated hyperbilirubinemia Dubin-Johnson or Rotor syndrome. This study is focused on unconjugated hyperbilirubinemia in adolescents including the non-typical manifestations and the defects of ABCC2 transporter and their phenotype in humans.

In newborns, unconjugated bilirubin (UCB) is not readily excreted, and when bilirubin levels exceed the serum albumin binding capacity, pathological levels of UCB exist. Hyperbilirubinemia may lead to auditory damage and ultimately cause a hearing disorder called auditory neuropathy/dys-synchrony, characterized by absent or abnormal brainstem auditory evoked potentials (BAEPs) with evidence of normal inner ear function assessed by either otoacoustic emissions or cochlear microphonic responses. Phototherapy and double volume exchange transfusion are used as treatment methods for neonatal hyperbilirubinemia. Spontaneously jaundiced Gunn rat pups given sulfadimethoxine to displace bilirubin from serum albumin develop bilirubin encephalopathy and have abnormal BAEPs comparable to human neonates. BAEPs are a noninvasive electrophysiological measure of neural function of the auditory system. High levels of calcineurin activity are believed to be involved in the mechanism of this bilirubin induced auditory neuropathy. FK506, a calcineurin inhibitor, was administered 3 hours prior to sulfa in concentrations of 0.1mg/kg, 1.0mg/kg, and 10.0mg/kg body weight. Due to the observation that all animals had abnormal BAEPs after treatment with FK506 and sulfa, it can be concluded that none of the treatment doses protected against bilirubin induced auditory impairment.

Tyrimo tikslas – įvertinti veiksnius, turinčius įtakos bilirubino koncentracijai naujagimio kraujyje, ir nustatyti kriterijų, kuriuo remiantis galima prognozuoti naujagimių hiperbilirubinemiją esant ABO antigeniniam netapatumui. Tyrimo uždaviniai: įvertinti motinos ir naujagimio veiksnius, turinčius įtakos naujagimio bilirubino koncentracijai kraujo serume 6 gyvenimo valandą; ištirti veiksnius, turinčius įtakos bilirubino koncentracijos naujagimio kraujo serume pokyčiui pirmą–trečią gyvenimo parą bei pokyčio prognozinę vertę; nustatyti bilirubino koncentracijos kraujo serume, hematokrito, retikulocitų, sferocitų kiekių ir tiesioginės Kumbso reakcijos vertę prognozuojant naujagimių hiperbilirubinemiją, esant ABO antigenininiam netapatumui; palyginti invazinį ir neinvazinį bilirubino koncentracijos nustatymo metodus esant ABO antigeniniam netapatumui; įvertinti perkutaninės bilirubinometrijos vertę diagnozuojant naujagimių hiperbilirubinemiją esant ABO antigeniniam netapatumui. / The aim of the study was to assess the factors influencing neonatal bilirubin level and to establish predictive criteria of neonatal hyperbilirubinemia in ABO antigenic incompatibility. The tasks to be carried out were as follows: to establish maternal and neonatal factors influencing neonatal total serum bilirubin at the age of 6 hoursTo establish the factors influencing the change of neonatal total serum bilirubin on days 1-3 of life and to identify the predictive value of this change. To establish the value of total serum bilirubin, hematocrit, reticulocyte, spherocyte and direct Coomb’s test in prognosing neonatal hyperbilirubinemia in ABO incompatibility, to compare non-invasive and invasive methods of total serum bilirubin assessment in the case of ABO incompatibility.

A icterícia costuma ser um fenômeno fisiológico em recém-nascidos saudáveis, contudo, hiperbilirrubinemia não conjugada grave ocorre em 5 a 6% dessa população. Tem sido sugerido que a variabilidade genética de genes de proteínas transportadoras de bilirrubina poderia aumentar o risco de hiperbilirrubinemia quando associada a outros fatores icterogênicos. O presente estudo incluiu neonatos com idade gestacional de 35 semanas ou mais e peso superior a 2000g com indicação para fototerapia. Os polimorfismos nos genes SLCO1B1 (rs4149056 e rs2306283) e SLCO1B3 (rs17680137 e rs2117032) foram analisados por sondas de hidrólise. Um total de 167 hiperbilirrubinêmicos e 247 recém-nascidos controles foi arrolado. Sexo, incompatibilidade ABO, peso ao nascimento e idade gestacional diferiram entre os grupos, mas as frequências alélicas e genotípicas dos polimorfismos dos genes SLCO1B não. Na análise por regressão logística, incompatibilidade ABO, idade gestacional e o alelo polimórfico T do rs2117032 permaneceram no modelo. A presença desse polimorfismo pareceu conferir proteção à hiperbilirrubinemia. Os indivíduos que eram homozigotos para o alelo G do rs2306283 e deficientes da enzima glicose-6-fosfato desidrogenase eram mais frequentes entre os casos. No presente estudo foram observadas apenas fracas interações entre os diferentes polimorfismos e os fatores clínico-ambientais. / Jaundice usually is a physiological phenomenon among newborns; however, severe hyperbilirubinemia occurs in 5% to 6% of this population. It has been suggested that genetic variation in the genes of bilirubin transporters could enhance the risk of hyperbilirubinemia when co-expressed with other icterogenic conditions. The present study included newborns with a gestational age of greater than 35 weeks and weights greater than 2000 g with indications for phototherapy. The polymorphisms from SLCO1B1 (rs4149056 and rs2306283) and SLCO1B3 (rs17680137 and rs2117032) genes were analyzed by hydrolysis probes. A total of 167 hyperbilirubinemic infants and 247 control subjects were enrolled. The gender, ABO incompatibility, birth weight, and gestational age differed between the groups but the allelic and genotypic frequency of the polymorphisms from SLCO1B genes did not. In logistic regression, the ABO incompatibility, gestational age, and polymorphic T allele of rs2117032 remained in the model. The presence of this polymorphism seemed to provide protection from hyperbilirubinemia. The individuals that were homozygous for the G allele of rs2306283 and glucose 6-phosphate-dehydrogenase deficient were more frequent among the cases. In the present study there were observed only weak associations between the different polymorphisms and the clinical/environmental factors.

A icterícia costuma ser um fenômeno fisiológico em recém-nascidos saudáveis, contudo, hiperbilirrubinemia não conjugada grave ocorre em 5 a 6% dessa população. Tem sido sugerido que a variabilidade genética de genes de proteínas transportadoras de bilirrubina poderia aumentar o risco de hiperbilirrubinemia quando associada a outros fatores icterogênicos. O presente estudo incluiu neonatos com idade gestacional de 35 semanas ou mais e peso superior a 2000g com indicação para fototerapia. Os polimorfismos nos genes SLCO1B1 (rs4149056 e rs2306283) e SLCO1B3 (rs17680137 e rs2117032) foram analisados por sondas de hidrólise. Um total de 167 hiperbilirrubinêmicos e 247 recém-nascidos controles foi arrolado. Sexo, incompatibilidade ABO, peso ao nascimento e idade gestacional diferiram entre os grupos, mas as frequências alélicas e genotípicas dos polimorfismos dos genes SLCO1B não. Na análise por regressão logística, incompatibilidade ABO, idade gestacional e o alelo polimórfico T do rs2117032 permaneceram no modelo. A presença desse polimorfismo pareceu conferir proteção à hiperbilirrubinemia. Os indivíduos que eram homozigotos para o alelo G do rs2306283 e deficientes da enzima glicose-6-fosfato desidrogenase eram mais frequentes entre os casos. No presente estudo foram observadas apenas fracas interações entre os diferentes polimorfismos e os fatores clínico-ambientais. / Jaundice usually is a physiological phenomenon among newborns; however, severe hyperbilirubinemia occurs in 5% to 6% of this population. It has been suggested that genetic variation in the genes of bilirubin transporters could enhance the risk of hyperbilirubinemia when co-expressed with other icterogenic conditions. The present study included newborns with a gestational age of greater than 35 weeks and weights greater than 2000 g with indications for phototherapy. The polymorphisms from SLCO1B1 (rs4149056 and rs2306283) and SLCO1B3 (rs17680137 and rs2117032) genes were analyzed by hydrolysis probes. A total of 167 hyperbilirubinemic infants and 247 control subjects were enrolled. The gender, ABO incompatibility, birth weight, and gestational age differed between the groups but the allelic and genotypic frequency of the polymorphisms from SLCO1B genes did not. In logistic regression, the ABO incompatibility, gestational age, and polymorphic T allele of rs2117032 remained in the model. The presence of this polymorphism seemed to provide protection from hyperbilirubinemia. The individuals that were homozygous for the G allele of rs2306283 and glucose 6-phosphate-dehydrogenase deficient were more frequent among the cases. In the present study there were observed only weak associations between the different polymorphisms and the clinical/environmental factors.

A icterícia costuma ser um fenômeno fisiológico em recém-nascidos saudáveis, contudo, hiperbilirrubinemia não conjugada grave ocorre em 5 a 6% dessa população. Tem sido sugerido que a variabilidade genética de genes de proteínas transportadoras de bilirrubina poderia aumentar o risco de hiperbilirrubinemia quando associada a outros fatores icterogênicos. O presente estudo incluiu neonatos com idade gestacional de 35 semanas ou mais e peso superior a 2000g com indicação para fototerapia. Os polimorfismos nos genes SLCO1B1 (rs4149056 e rs2306283) e SLCO1B3 (rs17680137 e rs2117032) foram analisados por sondas de hidrólise. Um total de 167 hiperbilirrubinêmicos e 247 recém-nascidos controles foi arrolado. Sexo, incompatibilidade ABO, peso ao nascimento e idade gestacional diferiram entre os grupos, mas as frequências alélicas e genotípicas dos polimorfismos dos genes SLCO1B não. Na análise por regressão logística, incompatibilidade ABO, idade gestacional e o alelo polimórfico T do rs2117032 permaneceram no modelo. A presença desse polimorfismo pareceu conferir proteção à hiperbilirrubinemia. Os indivíduos que eram homozigotos para o alelo G do rs2306283 e deficientes da enzima glicose-6-fosfato desidrogenase eram mais frequentes entre os casos. No presente estudo foram observadas apenas fracas interações entre os diferentes polimorfismos e os fatores clínico-ambientais. / Jaundice usually is a physiological phenomenon among newborns; however, severe hyperbilirubinemia occurs in 5% to 6% of this population. It has been suggested that genetic variation in the genes of bilirubin transporters could enhance the risk of hyperbilirubinemia when co-expressed with other icterogenic conditions. The present study included newborns with a gestational age of greater than 35 weeks and weights greater than 2000 g with indications for phototherapy. The polymorphisms from SLCO1B1 (rs4149056 and rs2306283) and SLCO1B3 (rs17680137 and rs2117032) genes were analyzed by hydrolysis probes. A total of 167 hyperbilirubinemic infants and 247 control subjects were enrolled. The gender, ABO incompatibility, birth weight, and gestational age differed between the groups but the allelic and genotypic frequency of the polymorphisms from SLCO1B genes did not. In logistic regression, the ABO incompatibility, gestational age, and polymorphic T allele of rs2117032 remained in the model. The presence of this polymorphism seemed to provide protection from hyperbilirubinemia. The individuals that were homozygous for the G allele of rs2306283 and glucose 6-phosphate-dehydrogenase deficient were more frequent among the cases. In the present study there were observed only weak associations between the different polymorphisms and the clinical/environmental factors.