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Wu C, Jin Y, Cui Y, Zhu Y, Yin S, Li C. Effects of bilirubin on the development and electrical activity of neural circuits. Front Cell Neurosci 2023; 17:1136250. [PMID: 37025700 PMCID: PMC10070809 DOI: 10.3389/fncel.2023.1136250] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 03/06/2023] [Indexed: 04/08/2023] Open
Abstract
In the past several decades, bilirubin has attracted great attention for central nervous system (CNS) toxicity in some pathological conditions with severely elevated bilirubin levels. CNS function relies on the structural and functional integrity of neural circuits, which are large and complex electrochemical networks. Neural circuits develop from the proliferation and differentiation of neural stem cells, followed by dendritic and axonal arborization, myelination, and synapse formation. The circuits are immature, but robustly developing, during the neonatal period. It is at the same time that physiological or pathological jaundice occurs. The present review comprehensively discusses the effects of bilirubin on the development and electrical activity of neural circuits to provide a systematic understanding of the underlying mechanisms of bilirubin-induced acute neurotoxicity and chronic neurodevelopmental disorders.
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Effects of Phototherapy on the Serum Magnesium Level in Neonates with Indirect Hyperbilirubinemia: A Prospective Cohort Study. Int J Pediatr 2022; 2022:5439630. [PMID: 35359348 PMCID: PMC8964202 DOI: 10.1155/2022/5439630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 03/11/2022] [Indexed: 11/30/2022] Open
Abstract
Objectives Neonatal jaundice or hyperbilirubinemia is one of the common findings in neonatal medicine. Severe disease can cause neurological damage and even Kernicterus. Magnesium ion is the most important N-methyl-D-aspartate receptor antagonist. The most commonly used treatment for jaundice is phototherapy, but the effect of phototherapy on serum magnesium is less investigated. In this study, we aim to investigate the effects of phototherapy on total serum magnesium levels in icteric neonates. Methods This prospective cohort study was carried out on 160 neonates with jaundice referring to the Besat Hospital of Hamadan. Based on the bilirubin level, newborns were divided into three subgroups of mild, moderate, and severe disease which were subjected to single, double, and intensive phototherapy, respectively. Serum bilirubin and magnesium levels were measured before and after phototherapy and compared using parametric tests. Results Subjects have a mean intrauterine age of 38.8 weeks and a jaundice onset age of 3.8 days. In all groups, serum magnesium levels were within the normal range before phototherapy. After phototherapy, on the other hand, the most reduction of total serum magnesium was in the double phototherapy group, which was −0.13 ± 0.42 mg/dl (P = 0.018). The change in serum magnesium level was not significant in the single phototherapy (−0.02 ± 0.25) and intensive phototherapy (−13.55 ± 2.73) groups (P > 0.05). Conclusion In the present study, serum magnesium did not increase significantly before the treatment in three groups. After treatment, a significant reduction was seen in the double phototherapy group.
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Hansen TWR, Wong RJ, Stevenson DK. Molecular Physiology and Pathophysiology of Bilirubin Handling by the Blood, Liver, Intestine, and Brain in the Newborn. Physiol Rev 2020; 100:1291-1346. [PMID: 32401177 DOI: 10.1152/physrev.00004.2019] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Bilirubin is the end product of heme catabolism formed during a process that involves oxidation-reduction reactions and conserves iron body stores. Unconjugated hyperbilirubinemia is common in newborn infants, but rare later in life. The basic physiology of bilirubin metabolism, such as production, transport, and excretion, has been well described. However, in the neonate, numerous variables related to nutrition, ethnicity, and genetic variants at several metabolic steps may be superimposed on the normal physiological hyperbilirubinemia that occurs in the first week of life and results in bilirubin levels that may be toxic to the brain. Bilirubin exists in several isomeric forms that differ in their polarities and is considered a physiologically important antioxidant. Here we review the chemistry of the bilirubin molecule and its metabolism in the body with a particular focus on the processes that impact the newborn infant, and how differences relative to older children and adults contribute to the risk of developing both acute and long-term neurological sequelae in the newborn infant. The final section deals with the interplay between the brain and bilirubin and its entry, clearance, and accumulation. We conclude with a discussion of the current state of knowledge regarding the mechanism(s) of bilirubin neurotoxicity.
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Affiliation(s)
- Thor W R Hansen
- Division of Paediatric and Adolescent Medicine, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway; and Department of Pediatrics, Stanford University School of Medicine, Stanford, California
| | - Ronald J Wong
- Division of Paediatric and Adolescent Medicine, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway; and Department of Pediatrics, Stanford University School of Medicine, Stanford, California
| | - David K Stevenson
- Division of Paediatric and Adolescent Medicine, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway; and Department of Pediatrics, Stanford University School of Medicine, Stanford, California
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Tátrai P, Krajcsi P. Prediction of Drug-Induced Hyperbilirubinemia by In Vitro Testing. Pharmaceutics 2020; 12:pharmaceutics12080755. [PMID: 32796590 PMCID: PMC7465333 DOI: 10.3390/pharmaceutics12080755] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 07/28/2020] [Accepted: 08/07/2020] [Indexed: 12/23/2022] Open
Abstract
Bilirubin, the end product of heme catabolism, is produced continuously in the body and may reach toxic levels if accumulates in the serum and tissues; therefore, a highly efficient mechanism evolved for its disposition. Normally, unconjugated bilirubin enters hepatocytes through the uptake transporters organic anion transporting polypeptide (OATP) 1B1 and 1B3, undergoes glucuronidation by the Phase II enzyme UDP glucuronosyltransferase 1A1 (UGT1A1), and conjugated forms are excreted into the bile by the canalicular export pump multidrug resistance protein 2 (MRP2). Any remaining conjugated bilirubin is transported back to the blood by MRP3 and passed on for uptake and excretion by downstream hepatocytes or the kidney. The bile salt export pump BSEP as the main motor of bile flow is indirectly involved in bilirubin disposition. Genetic mutations and xenobiotics that interfere with this machinery may impede bilirubin disposition and cause hyperbilirubinemia. Several pharmaceutical compounds are known to cause hyperbilirubinemia via inhibition of OATP1Bs, UGT1A1, or BSEP. Herein we briefly review the in vitro prediction methods that serve to identify drugs with a potential to induce hyperbilirubinemia. In vitro assays can be deployed early in drug development and may help to minimize late-stage attrition. Based on current evidence, drugs that behave as mono- or multispecific inhibitors of OATP1B1, UGT1A1, and BSEP in vitro are at risk of causing clinically significant hyperbilirubinemia. By integrating inhibition data from in vitro assays, drug serum concentrations, and clinical reports of hyperbilirubinemia, predictor cut-off values have been established and are provisionally suggested in this review. Further validation of in vitro readouts to clinical outcomes is expected to enhance the predictive power of these assays.
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Affiliation(s)
- Péter Tátrai
- Solvo Biotechnology, Science Park, Building B1, 4-20 Irinyi József utca, H-1117 Budapest, Hungary;
| | - Péter Krajcsi
- Solvo Biotechnology, Science Park, Building B1, 4-20 Irinyi József utca, H-1117 Budapest, Hungary;
- Faculty of Health Sciences, Semmelweis University, H-1085 Budapest, Hungary
- Faculty of Information Technology and Bionics, Péter Pázmány Catholic University, H-1083 Budapest, Hungary
- Correspondence:
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Zhou C, Sun R, Sun C, Gu M, Guo C, Zhang J, Du Y, Gu H, Liu Q. Minocycline protects neurons against glial cells-mediated bilirubin neurotoxicity. Brain Res Bull 2019; 154:102-105. [PMID: 31733348 DOI: 10.1016/j.brainresbull.2019.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 11/05/2019] [Accepted: 11/11/2019] [Indexed: 10/25/2022]
Abstract
Unconjugated bilirubin, the end product of heme catabolism and antioxidant, induced brain damage in human neonates is a well-recognized clinical syndrome. However, the cellular and molecular mechanisms underlying bilirubin neurotoxicity remain unclear. To characterize the sequence of events leading to bilirubin-induced neurotoxicity, we investigated whether bilirubin-induced glial activation was involved in bilirubin neurotoxicity by exposing co-cultured rat glial cells and cerebellar granule neurons (CGN) to bilirubin. We found that bilirubin could markedly induce the expression of TNF-α and iNOS in glial cells, and even at low concentrations, the co-culture of glial cells with neurons significantly enhances neurotoxicity of bilirubin. Pretreatment of the co-cultured cells with minocycline protected CGN from glia-mediated bilirubin neurotoxicity and inhibited overexpression of TNF-α and iNOS in glia. Furthermore, we found that high doses of bilirubin were able to induce glial injury, and minocycline attenuated bilirubin-induced glial cell death. Our data suggest that glial cells play an important role in brain damage caused by bilirubin, and minocycline blocks bilirubin-induced encephalopathy possibly by directly and indirectly inhibiting neuronal death pathways.
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Affiliation(s)
- Changwei Zhou
- Department of Orthopedics, The 2nd Affiliated Hospital of Harbin Medical University, Harbin, 150086, PR China
| | - Rong Sun
- Department of Outpatient OR, The 1st Affiliated Hospital of Harbin Medical University, Harbin, 150086, PR China
| | - Chongyi Sun
- Department of Orthopedics, The 2nd Affiliated Hospital of Harbin Medical University, Harbin, 150086, PR China
| | - Minghao Gu
- Department of Orthopedics, The 2nd Affiliated Hospital of Harbin Medical University, Harbin, 150086, PR China
| | - Chuan Guo
- Department of Orthopedics, The 2nd Affiliated Hospital of Harbin Medical University, Harbin, 150086, PR China
| | - Jiyan Zhang
- Department of Orthopedics, The 2nd Affiliated Hospital of Harbin Medical University, Harbin, 150086, PR China
| | - Yansheng Du
- Department of Neurology, School of Medicine, Indiana University, Indianapolis, IN, 46202, USA
| | - Huiying Gu
- Department of Neurology, School of Medicine, Indiana University, Indianapolis, IN, 46202, USA.
| | - Qingpeng Liu
- Department of Orthopedics, The 2nd Affiliated Hospital of Harbin Medical University, Harbin, 150086, PR China.
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6
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Le Pichon JB, Riordan SM, Shapiro SM. Hyperbilirubinemia and the Risk for Brain Injury. Neurology 2019. [DOI: 10.1016/b978-0-323-54392-7.00010-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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7
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Maternal Administration of Cichorium intybus L. Extract Decreases the Plasma Total and Conjugated Bilirubin Level in Rat Neonates. Jundishapur J Nat Pharm Prod 2018. [DOI: 10.5812/jjnpp.14043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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8
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Mancuso C. Bilirubin and brain: A pharmacological approach. Neuropharmacology 2017; 118:113-123. [PMID: 28315352 DOI: 10.1016/j.neuropharm.2017.03.013] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 03/09/2017] [Accepted: 03/12/2017] [Indexed: 01/01/2023]
Abstract
For many decades, the world scientific literature has accounted for a number of works on the biological effects of bilirubin-IXalpha (BR). The first studies focused on the neurotoxic effects of the excessive production of BR, in particular regarding both physiological neonatal jaundice and the more severe ones, typically as consequences of severe hemolysis or other underlying diseases. Only since 1987, has significant evidence, however, underlined the neuroprotective role of BR linked to the scavenging effect of free radicals as reactive oxygen species and nitric oxide and its congeners. Despite the presence in the literature of many excellent papers dealing with the multiple roles played by BR in health and disease, there were very few and somewhat dated reviews that summarize the key findings related to the neuroprotective and neurotoxic effects of the bile pigment and underlying mechanisms. In light of the previous statements, the aim of this review is to provide a summary of the main discoveries in the last years on the effects of BR on the central nervous system. An analytical description about the synthesis of BR, its distribution in the systemic circulation, liver metabolism and elimination through feces and urine will be provided, together with the main mechanisms claimed to describe the neurotoxicity and neuroprotection by the bile pigment. Finally, the possible translational aspects of pharmacological modulation in the production of BR in order to prevent or counteract toxic effects or enhance the protective actions, will be discussed.
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Affiliation(s)
- Cesare Mancuso
- Institute of Pharmacology, Catholic University School of Medicine, Largo F. Vito, 1-00168 Rome, Italy.
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The effect of bilirubin on the excitability of mitral cells in the olfactory bulb of the rat. Sci Rep 2016; 6:32872. [PMID: 27611599 PMCID: PMC5017196 DOI: 10.1038/srep32872] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 08/16/2016] [Indexed: 11/17/2022] Open
Abstract
Olfactory dysfunction is a common clinical phenomenon observed in various liver diseases. Previous studies have shown a correlation between smell disorders and bilirubin levels in patients with hepatic diseases. Bilirubin is a well-known neurotoxin; however, its effect on neurons in the main olfactory bulb (MOB), the first relay in the olfactory system, has not been examined. We investigated the effect of bilirubin (>3 μM) on mitral cells (MCs), the principal output neurons of the MOB. Bilirubin increased the frequency of spontaneous firing and the frequency but not the amplitude of spontaneous excitatory postsynaptic currents (sEPSCs). TTX completely blocked sEPSCs in almost all of the cells tested. Bilirubin activity was partially blocked by N-methyl-D-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepro pionic acid (AMPA) receptor antagonists. Furthermore, we found that bilirubin increased the frequency of intrinsic firing independent of synaptic transmission in MCs. Our findings suggest that bilirubin enhances glutamatergic transmission and strengthens intrinsic firing independent of synaptic transmission, all of which cause hyperexcitability in MCs. Our findings provide the basis for further investigation into the mechanisms underlying olfactory dysfunction that are often observed in patients with severe liver disease.
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Ronke C, Dannemann M, Halbwax M, Fischer A, Helmschrodt C, Brügel M, André C, Atencia R, Mugisha L, Scholz M, Ceglarek U, Thiery J, Pääbo S, Prüfer K, Kelso J. Lineage-Specific Changes in Biomarkers in Great Apes and Humans. PLoS One 2015; 10:e0134548. [PMID: 26247603 PMCID: PMC4527672 DOI: 10.1371/journal.pone.0134548] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 07/10/2015] [Indexed: 12/15/2022] Open
Abstract
Although human biomedical and physiological information is readily available, such information for great apes is limited. We analyzed clinical chemical biomarkers in serum samples from 277 wild- and captive-born great apes and from 312 healthy human volunteers as well as from 20 rhesus macaques. For each individual, we determined a maximum of 33 markers of heart, liver, kidney, thyroid and pancreas function, hemoglobin and lipid metabolism and one marker of inflammation. We identified biomarkers that show differences between humans and the great apes in their average level or activity. Using the rhesus macaques as an outgroup, we identified human-specific differences in the levels of bilirubin, cholinesterase and lactate dehydrogenase, and bonobo-specific differences in the level of apolipoprotein A-I. For the remaining twenty-nine biomarkers there was no evidence for lineage-specific differences. In fact, we find that many biomarkers show differences between individuals of the same species in different environments. Of the four lineage-specific biomarkers, only bilirubin showed no differences between wild- and captive-born great apes. We show that the major factor explaining the human-specific difference in bilirubin levels may be genetic. There are human-specific changes in the sequence of the promoter and the protein-coding sequence of uridine diphosphoglucuronosyltransferase 1 (UGT1A1), the enzyme that transforms bilirubin and toxic plant compounds into water-soluble, excretable metabolites. Experimental evidence that UGT1A1 is down-regulated in the human liver suggests that changes in the promoter may be responsible for the human-specific increase in bilirubin. We speculate that since cooking reduces toxic plant compounds, consumption of cooked foods, which is specific to humans, may have resulted in relaxed constraint on UGT1A1 which has in turn led to higher serum levels of bilirubin in humans.
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Affiliation(s)
- Claudius Ronke
- Institute of Laboratory Medicine, Clinical Chemistry and Molecular Diagnostics, University Hospital Leipzig, Leipzig, Germany
- * E-mail:
| | - Michael Dannemann
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Michel Halbwax
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Anne Fischer
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Christin Helmschrodt
- Institute of Laboratory Medicine, Clinical Chemistry and Molecular Diagnostics, University Hospital Leipzig, Leipzig, Germany
| | - Mathias Brügel
- Institute of Laboratory Medicine, Clinical Chemistry and Molecular Diagnostics, University Hospital Leipzig, Leipzig, Germany
| | - Claudine André
- Lola Ya Bonobo Sanctuary, “Petites Chutes de la Lukaya,” Kinshasa, Democratic Republic of Congo
| | - Rebeca Atencia
- Réserve Naturelle Sanctuaire à Chimpanzés de Tchimpounga, Jane Goodall Institute, Pointe-Noire, Republic of Congo
| | - Lawrence Mugisha
- Conservation & Ecosystem Health Alliance (CEHA), Kampala, Uganda
- College of Veterinary Medicine, Animal Resources & Biosecurity, Makerere University, Kampala, Uganda
| | - Markus Scholz
- Institute for Medical Informatics, Statistics and Epidemiology, University of Leipzig, Leipzig, Germany
| | - Uta Ceglarek
- Institute of Laboratory Medicine, Clinical Chemistry and Molecular Diagnostics, University Hospital Leipzig, Leipzig, Germany
| | - Joachim Thiery
- Institute of Laboratory Medicine, Clinical Chemistry and Molecular Diagnostics, University Hospital Leipzig, Leipzig, Germany
| | - Svante Pääbo
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Kay Prüfer
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Janet Kelso
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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Impairment of enzymatic antioxidant defenses is associated with bilirubin-induced neuronal cell death in the cerebellum of Ugt1 KO mice. Cell Death Dis 2015; 6:e1739. [PMID: 25950469 PMCID: PMC4669693 DOI: 10.1038/cddis.2015.113] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 03/16/2015] [Accepted: 03/18/2015] [Indexed: 01/14/2023]
Abstract
Severe hyperbilirubinemia is toxic during central nervous system development. Prolonged and uncontrolled high levels of unconjugated bilirubin lead to bilirubin-induced encephalopathy and eventually death by kernicterus. Despite extensive studies, the molecular and cellular mechanisms of bilirubin toxicity are still poorly defined. To fill this gap, we investigated the molecular processes underlying neuronal injury in a mouse model of severe neonatal jaundice, which develops hyperbilirubinemia as a consequence of a null mutation in the Ugt1 gene. These mutant mice show cerebellar abnormalities and hypoplasia, neuronal cell death and die shortly after birth because of bilirubin neurotoxicity. To identify protein changes associated with bilirubin-induced cell death, we performed proteomic analysis of cerebella from Ugt1 mutant and wild-type mice. Proteomic data pointed-out to oxidoreductase activities or antioxidant processes as important intracellular mechanisms altered during bilirubin-induced neurotoxicity. In particular, they revealed that down-representation of DJ-1, superoxide dismutase, peroxiredoxins 2 and 6 was associated with hyperbilirubinemia in the cerebellum of mutant mice. Interestingly, the reduction in protein levels seems to result from post-translational mechanisms because we did not detect significant quantitative differences in the corresponding mRNAs. We also observed an increase in neuro-specific enolase 2 both in the cerebellum and in the serum of mutant mice, supporting its potential use as a biomarker of bilirubin-induced neurological damage. In conclusion, our data show that different protective mechanisms fail to contrast oxidative burst in bilirubin-affected brain regions, ultimately leading to neurodegeneration.
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12
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Alteration in 5-HT2C, NMDA Receptor and IP3 in Cerebral Cortex of Epileptic Rats: Restorative Role of Bacopa monnieri. Neurochem Res 2014; 40:216-25. [DOI: 10.1007/s11064-014-1472-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 09/30/2014] [Accepted: 10/30/2014] [Indexed: 12/21/2022]
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Hou C, Norcia AM, Madan A, Good WV. Visuocortical function in infants with a history of neonatal jaundice. Invest Ophthalmol Vis Sci 2014; 55:6443-9. [PMID: 25183760 DOI: 10.1167/iovs.14-14261] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE High concentrations of unconjugated bilirubin are neurotoxic and cause brain damage in newborn infants. However, the exact level of bilirubin that may be neurotoxic in a given infant is unknown. The aim of this study was to use a quantitative measure of neural activity, the swept parameter visual evoked potential (sVEP) to determine the relationship between neonatal bilirubin levels and visual responsivity several months later. METHODS We compared sVEP response functions over a wide range of contrast, spatial frequency, and Vernier offset sizes in 16 full-term infants with high bilirubin levels (>10 mg/dL) and 18 age-matched infants with no visible neonatal jaundice, all enrolled at 14 to 22 weeks of age. The group means of sVEP thresholds and suprathreshold response amplitudes were compared. The correlation between individual sVEP thresholds and bilirubin levels in jaundiced infants was studied. RESULTS Infants who had a history of neonatal jaundice showed lower response amplitudes (P < 0.05) and worse or immeasurable sVEP thresholds compared with control infants for all three measures (P < 0.05). Swept parameter visual evoked potential thresholds for Vernier offset were correlated with bilirubin level (P < 0.05), but spatial acuity and contrast sensitivity measures in the infants with neonatal jaundice were not (P > 0.05). CONCLUSIONS These results indicate that elevated neonatal bilirubin levels affect measures of visual function in infancy up to at least 14 to 22 weeks of postnatal age.
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Affiliation(s)
- Chuan Hou
- Smith-Kettlewell Eye Research Institute, San Francisco, California, United States
| | - Anthony M Norcia
- Department of Psychology, Stanford University, Stanford, California, United States
| | - Ashima Madan
- Stanford University School of Medicine, Pediatrics, Stanford, California, United States
| | - William V Good
- Smith-Kettlewell Eye Research Institute, San Francisco, California, United States
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Chang JH, Plise E, Cheong J, Ho Q, Lin M. Evaluating the In Vitro Inhibition of UGT1A1, OATP1B1, OATP1B3, MRP2, and BSEP in Predicting Drug-Induced Hyperbilirubinemia. Mol Pharm 2013; 10:3067-75. [DOI: 10.1021/mp4001348] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Jae H. Chang
- Drug Metabolism and Pharmacokinetics, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080,
United States
| | - Emile Plise
- Drug Metabolism and Pharmacokinetics, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080,
United States
| | - Jonathan Cheong
- Drug Metabolism and Pharmacokinetics, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080,
United States
| | - Quynh Ho
- Drug Metabolism and Pharmacokinetics, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080,
United States
| | - Molly Lin
- Drug Metabolism and Pharmacokinetics, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080,
United States
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15
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Ye HB, Wang J, Zhang WT, Shi HB, Yin SK. Taurine attenuates bilirubin-induced neurotoxicity in the auditory system in neonatal guinea pigs. Int J Pediatr Otorhinolaryngol 2013; 77:647-54. [PMID: 23273639 DOI: 10.1016/j.ijporl.2012.11.037] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Revised: 11/17/2012] [Accepted: 11/20/2012] [Indexed: 10/27/2022]
Abstract
OBJECTIVES Previous work showed that taurine protects neurons against unconjugated bilirubin (UCB)-induced neurotoxicity by maintaining intracellular calcium homeostasis, membrane integrity, and mitochondrial function, thereby preventing apoptosis from occurring, in primary neuron cultures. In this study, we investigated whether taurine could protect the auditory system against the neurotoxicity associated with hyperbilirubinemia in an in vivo model. METHODS Hyperbilirubinemia was established in neonatal guinea pigs by intraperitoneal injection of UCB. Hearing function was observed in electrocochleograms (ECochGs) and auditory brainstem responses (ABRs) recorded before and 1, 8, 24, and 72 h after UCB injection. For morphological evaluations, animals were sacrificed at 8h post-injection, and the afferent terminals beneath the inner hair cells (IHCs), spiral ganglion neurons (SGNs), and their fibers were examined. RESULTS It was found that UCB injection significantly increased latencies and inter-wave intervals, and thresholds of ABR and compound action potentials, and caused marked damage to type I SGNs, their axons, and terminals to cochlear IHCs. When baby guinea pigs were pretreated with taurine for 5 consecutive days and then injected with bilirubin, electrophysiological abnormalities and morphological damage were attenuated significantly in both the peripheral and central auditory system. CONCLUSIONS From these observations, it was concluded that taurine limited bilirubin-induced neural damage in the auditory system. These findings may contribute to the development of taurine as a broad-spectrum agent for preventing and/or treating hearing loss in neonatal jaundice.
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Affiliation(s)
- Hai-Bo Ye
- Department of Otorhinolaryngology, Affiliated Sixth People's Hospital of Shanghai Jiaotong University, 600 Yishan Road, Shanghai 200233, China
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NMDA and AMPA receptor mediated excitotoxicity in cerebral cortex of streptozotocin induced diabetic rat: ameliorating effects of curcumin. Chem Biol Interact 2012; 201:39-48. [PMID: 23267840 DOI: 10.1016/j.cbi.2012.11.024] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2012] [Revised: 11/11/2012] [Accepted: 11/26/2012] [Indexed: 12/28/2022]
Abstract
Functional activity of neurotransmitter receptor and their sensitivity to regulation are altered in DM. We evaluated the neuroprotective effect of curcumin in glutamate mediated excitotoxicity in cerebral cortex of streptozotocin induced diabetic rats. Gene expression studies in diabetic rats showed a down regulation of glutamate decarboxylase mRNA leading to accumulation of glutamate. Radioreceptor binding assays showed a significant increase in α-amino-3-hydroxy-5-methyl-4-isoxazole propionate and N-methyl-D-aspartate receptors density which was confirmed by immunohistochemical studies. Decreased glutathione peroxidases gene expression indicates enhanced oxidative stress in diabetic rats. This leads to decreased expression of glutamate aspartate transporter, which in turn reduces glutamate transport. All these events lead to excitotoxic neuronal death in the cerebral cortex, which was confirmed by the increased expression of caspase 3, caspase 8 and BCL2-associated X protein. Curcumin and insulin treatment reversed these altered parameters to near control. We establish, a novel therapeutic role of curcumin by reducing the glutamate mediated excitotoxicity in cerebral cortex of diabetes through modulating the altered neurochemical parameters.
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Oxidative Stress Induced NMDA Receptor Alteration Leads to Spatial Memory Deficits in Temporal Lobe Epilepsy: Ameliorative Effects of Withania somnifera and Withanolide A. Neurochem Res 2012; 37:1915-27. [DOI: 10.1007/s11064-012-0810-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2012] [Revised: 05/11/2012] [Accepted: 05/26/2012] [Indexed: 10/28/2022]
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Silva SL, Vaz AR, Diógenes MJ, van Rooijen N, Sebastião AM, Fernandes A, Silva RFM, Brites D. Neuritic growth impairment and cell death by unconjugated bilirubin is mediated by NO and glutamate, modulated by microglia, and prevented by glycoursodeoxycholic acid and interleukin-10. Neuropharmacology 2012; 62:2398-408. [PMID: 22361233 DOI: 10.1016/j.neuropharm.2012.02.002] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 02/01/2012] [Accepted: 02/07/2012] [Indexed: 12/28/2022]
Abstract
Neuronal oxidative damage and cell death by unconjugated bilirubin (UCB) showed to be mediated by overstimulation of glutamate receptors and nitric oxide (NO) production, which was abrogated by the bile acid glycoursodeoxycholic acid (GUDCA). Microglia, a crucial mediator of CNS inflammation, evidenced to react to UCB by releasing glutamate and NO before becoming senescent. Our studies demonstrated that neurite outgrowth deficits are produced in neurons exposed to UCB and that conditioned media from these UCB-treated neurons further stimulate NO production by microglia. Nevertheless, microglia protective and/or harmful effects in neonatal jaundice are poorly understood, or unrecognized. Here, we investigated the role of microglia, glutamate and NO in the impairment of neurite sprouting by UCB. Therapeutic potential of the anti-inflammatory cytokine interleukin (IL)-10 and GUDCA was also evaluated. By using MK-801 (a NMDA glutamate-subtype receptor antagonist) and L-NAME (a non-specific NO synthase inhibitor) we found that glutamate and NO are determinants in the early and enduring deficits in neurite extension and ramification induced by UCB. Both GUDCA and IL-10 prevented these effects and decreased the production of glutamate and NO. Only GUDCA was able to counteract neuronal death and synaptic changes. Data from organotypic-cultured hippocampal slices, depleted or non-depleted in microglia, supported that microglia participate in glutamate homeostasis and contribute to NO production and cell demise, which were again abrogated by GUDCA. Collectively our data suggest that microglia is a key player in UCB-induced neurotoxicity and that GUDCA might be a valuable preventive therapy in neonates at risk of UCB encephalopathy.
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Affiliation(s)
- Sandra L Silva
- Research Institute for Medicines and Pharmaceutical Sciences (iMed.UL), Faculty of Pharmacy, University of Lisbon, Av. Professor Gama Pinto, 1649-003 Lisbon, Portugal.
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Li CY, Shi HB, Song NY, Yin SK. Bilirubin enhances neuronal excitability by increasing glutamatergic transmission in the rat lateral superior olive. Toxicology 2011; 284:19-25. [PMID: 21440030 DOI: 10.1016/j.tox.2011.03.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Revised: 03/16/2011] [Accepted: 03/17/2011] [Indexed: 11/26/2022]
Abstract
Hyperbilirubinemia is one of the most common clinical phenomena observed in human newborns. To achieve effective therapeutic treatment, numerous studies have been done to determine the molecular mechanisms of bilirubin-induced neuronal excitotoxicity. However, there is no conclusive evidence for the involvement of glutamatergic synaptic transmission in bilirubin-induced neuronal hyperexcitation and excitotoxicity. In the present study, using gramicidin-perforated patch-clamp techniques, spontaneous excitatory postsynaptic currents (sEPSCs) were recorded from lateral superior olive (LSO) neurons isolated from postnatal 11-14-day-old (P11-14) rats. The application of 3 μM bilirubin increased the frequency, but not the amplitude, of sEPSCs. The action of bilirubin was tetrodotoxin (TTX)-insensitive, as bilirubin also increased the frequency, but not the amplitude, of mEPSCs. The amplitudes of GABA-activated (I(GABA)) and glutamate-activated (I(glu)) currents were not affected by bilirubin. Under current-clamp conditions, no spontaneous action potentials were observed in control solution. However, the application of 3 μM bilirubin for 4-6 min evoked a considerable rate of action-potential firing. The evoked firing was partially occluded by D,L-2-amino-5-phosphonovaleric acid (APV), an NMDA receptor antagonist, but completely inhibited by a combination of APV and 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo[f]quinoxaline-2,3-dione (NBQX), an AMPA receptor antagonist. These results indicate that bilirubin facilitates presynaptic glutamate release, enhances glutamatergic synaptic transmission by activating postsynaptic AMPA and NMDA receptors, and leads to neuronal hyperexcitation. This study provides a better understanding of the mechanism of bilirubin-induced excitotoxicity and determines for the first time that both AMPA and NMDA receptors are likely involved in the excitotoxicity produced by bilirubin.
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Affiliation(s)
- Chun-Yan Li
- Department of Otorhinolaryngology, Affiliated Sixth People's Hospital of Shanghai Jiaotong University, 600 Yishan Road, Shanghai 200233, China
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20
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Nandhu MS, Paul J, Kuruvila KP, Abraham PM, Antony S, Paulose CS. Glutamate and NMDA receptors activation leads to cerebellar dysfunction and impaired motor coordination in unilateral 6-hydroxydopamine lesioned Parkinson's rat: functional recovery with bone marrow cells, serotonin and GABA. Mol Cell Biochem 2011; 353:47-57. [PMID: 21384157 DOI: 10.1007/s11010-011-0773-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Accepted: 02/24/2011] [Indexed: 10/18/2022]
Abstract
Parkinson's disease (PD) is a chronic progressive neurodegenerative movement disorder characterised by a profound and selective loss of nigrostriatal dopaminergic neurons. In Parkinson's disease, degeneration of dopaminergic neurons involves motor structures including basal ganglia and cerebellum. Glutamate-mediated degeneration of the cerebellum contributes to motor dysfunction in Parkinson's disease. Targeting neurotransmitter system beyond the dopamine system is of important, both for the motor and for the nonmotor problems of Parkinson's disease. The aim of this study is to assess the glutamate and NMDA receptor functional regulation and motor performance of 6-hydroxydopamine-induced Parkinson's rat and the effects of serotonin (5-HT), gamma aminobutyric acid (GABA) and bone marrow cells supplementation infused intranigrally to substantia nigra individually and in combination. Scatchard analysis of total glutamate and NMDA receptor binding parameters showed a significant increase in B (max) (P < 0.001) in the cerebellum of 6-hydroxydopamine infused rat compared to control. Real-Time PCR amplification of NMDA2B, mGluR5, and bax were significantly (P < 0.001) upregulated in cerebellum of 6-hydroxydopamine infused rats compared to control. Activation of the glutamate and NMDA receptors gave rise to an increased cAMP and IP3 content in the cerebellum. Gene expression studies of GLAST and CREB showed a significant (P < 0.001) down regulation in 6-OHDA infused rats compared to control. Behavioural studies were carried out to confirm the biochemical and molecular studies. Serotonin and GABA along with bone marrow cells in combination showed reversal of glutamate receptors and motor abnormality shown in the Parkinson's rat model. The therapeutic significance in Parkinson's disease is of prominence.
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Affiliation(s)
- M S Nandhu
- Department of Biotechnology, Molecular Neurobiology and Cell Biology Unit, Centre for Neuroscience, Cochin University of Science and Technology, Cochin 682022, Kerala, India
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21
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Nandhu MS, Paul J, Kuruvilla KP, Malat A, Romeo C, Paulose CS. Enhanced glutamate, IP3 and cAMP activity in the cerebral cortex of unilateral 6-hydroxydopamine induced Parkinson's rats: effect of 5-HT, GABA and bone marrow cell supplementation. J Biomed Sci 2011; 18:5. [PMID: 21235809 PMCID: PMC3027092 DOI: 10.1186/1423-0127-18-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Accepted: 01/15/2011] [Indexed: 12/29/2022] Open
Abstract
Parkinson's disease is characterized by progressive cell death in the substantia nigra pars compacta, which leads to dopamine depletion in the striatum and indirectly to cortical dysfunction. Increased glutamatergic transmission in the basal ganglia is implicated in the pathophysiology of Parkinson's disease and glutamate receptor mediated excitotoxicity has been suggested to be one of the possible causes of the neuronal degeneration. In the present study, the effects of serotonin, gamma-aminobutyric acid and bone marrow cells infused intranigrally to substantia nigra individually and in combination on unilateral 6-hydroxydopamine induced Parkinson's rat model was analyzed. Scatchard analysis of total glutamate and NMDA receptor binding parameters showed a significant increase in Bmax (P < 0.001) in the cerebral cortex of 6-hydroxydopamine infused rat compared to control. Real Time PCR amplification of NMDA2B, mGluR5, bax, and ubiquitin carboxy-terminal hydrolase were up regulated in cerebral cortex of 6-hydroxydopamine infused rats compared to control. Gene expression studies of GLAST, ά-Synuclien and Cyclic AMP response element-binding protein showed a significant (P < 0.001) down regulation in 6-OHDA infused rats compared to control. Behavioural studies were carried out to confirm the biochemical and molecular studies. Serotonin and GABA along with bone marrow cells in combination showed reversal of glutamate receptors and behaviour abnormality shown in the Parkinson's rat model. The therapeutic significance in Parkinson's disease is of prominence.
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Affiliation(s)
- M S Nandhu
- Molecular Neurobiology and Cell Biology Unit, Centre for Neuroscience, Department of Biotechnology, Cochin University of Science and Technology, Cochin - 682 022, and Kerala, India
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Brito MA, Vaz AR, Silva SL, Falcão AS, Fernandes A, Silva RFM, Brites D. N-methyl-aspartate receptor and neuronal nitric oxide synthase activation mediate bilirubin-induced neurotoxicity. Mol Med 2010; 16:372-80. [PMID: 20593111 PMCID: PMC2935951 DOI: 10.2119/molmed.2009.00152] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Accepted: 06/28/2010] [Indexed: 01/02/2023] Open
Abstract
Hyperbilirubinemia may lead to neurotoxicity and neuronal death. Although the mechanisms of nerve cell damage by unconjugated bilirubin (UCB) appear to involve a disruption of the redox status and excitotoxicity, the contribution of nitric oxide (NO·) and of N-methyl-D-aspartate (NMDA) glutamate receptors is unclear. We investigated the role of NO· and NMDA glutamate receptors in the pathways of nerve cell demise by UCB. Neurons were incubated with 100 micromol/L UCB, in the presence of 100 micromol/L human serum albumin for 4 h at 37ºC, alone or in combination with N-ω-nitro-L-arginine methyl ester (L-NAME) (an inhibitor of neuronal nitric oxide synthase [nNOS]), hemoglobin (an NO· scavenger) or (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate (MK-801) (an NMDA-receptor antagonist). Exposure to UCB led to increased expression of nNOS and production of both NO· and cyclic guanosine 3',5'-monophosphate (cGMP), along with protein oxidation and depletion of glutathione. These events concurred for cell dysfunction and death and were counteracted by L-NAME. Moreover, the UCB-induced loss of neuronal viability was abolished by hemoglobin, whereas the activation of nNOS and production of both NO· and cGMP were counteracted by MK-801, resulting in significant protection from cell dysfunction and death. These results reinforce the involvement of oxidative stress by showing that nerve cell damage by UCB is mediated by NO· and therefore is counteracted by NO· inhibitors or scavengers. Our findings strongly suggest that the activation of nNOS and neurotoxicity occur through the engagement of NMDA receptors. These data reveal a role for overstimulation of glutamate receptors in mediating oxidative damage by UCB.
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Affiliation(s)
- Maria A Brito
- Research Institute for Medicines and Pharmaceutical Sciences, Faculdade de Farmácia, University of Lisbon, Lisbon, Portugal.
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23
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Enhanced NMDAR1, NMDA2B and mGlu5 receptors gene expression in the cerebellum of insulin induced hypoglycaemic and streptozotocin induced diabetic rats. Eur J Pharmacol 2010; 630:61-8. [DOI: 10.1016/j.ejphar.2009.12.024] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2009] [Revised: 11/29/2009] [Accepted: 12/15/2009] [Indexed: 11/15/2022]
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Calligaris R, Bellarosa C, Foti R, Roncaglia P, Giraudi P, Krmac H, Tiribelli C, Gustincich S. A transcriptome analysis identifies molecular effectors of unconjugated bilirubin in human neuroblastoma SH-SY5Y cells. BMC Genomics 2009; 10:543. [PMID: 19925663 PMCID: PMC2789749 DOI: 10.1186/1471-2164-10-543] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Accepted: 11/19/2009] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND The deposition of unconjugated bilirubin (UCB) in selected regions of the brain results in irreversible neuronal damage, or Bilirubin Encephalopathy (BE). Although UCB impairs a large number of cellular functions in other tissues, the basic mechanisms of neurotoxicity have not yet been fully clarified. While cells can accumulate UCB by passive diffusion, cell protection may involve multiple mechanisms including the extrusion of the pigment as well as pro-survival homeostatic responses that are still unknown. RESULTS Transcriptome changes induced by UCB exposure in SH-SY5Y neuroblastoma cell line were examined by high density oligonucleotide microarrays. Two-hundred and thirty genes were induced after 24 hours. A Gene Ontology (GO) analysis showed that at least 50 genes were directly involved in the endoplasmic reticulum (ER) stress response. Validation of selected ER stress genes is shown by quantitative RT-PCR. Analysis of XBP1 splicing and DDIT3/CHOP subcellular localization is presented. CONCLUSION These results show for the first time that UCB exposure induces ER stress response as major intracellular homeostasis in surviving neuroblastoma cells in vitro.
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Vaz AR, Delgado-Esteban M, Brito MA, Bolaños JP, Brites D, Almeida A. Bilirubin selectively inhibits cytochrome c oxidase activity and induces apoptosis in immature cortical neurons: assessment of the protective effects of glycoursodeoxycholic acid. J Neurochem 2009; 112:56-65. [PMID: 19818102 DOI: 10.1111/j.1471-4159.2009.06429.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
High levels of unconjugated bilirubin (UCB) may initiate encephalopathy in neonatal life, mainly in pre-mature infants. The molecular mechanisms of this bilirubin-induced neurologic dysfunction (BIND) are not yet clarified and no neuroprotective strategy is currently worldwide accepted. Here, we show that UCB, at conditions mimicking those of hyperbilirubinemic newborns (50 microM UCB in the presence of 100 muM human serum albumin), rapidly (within 1 h) inhibited cytochrome c oxidase activity and ascorbate-driven oxygen consumption in 3 days in vitro rat cortical neurons. This was accompanied by a bioenergetic and oxidative crisis, and apoptotic cell death, as judged by the collapse of the inner-mitochondrial membrane potential, increased glycolytic activity, superoxide anion radical production, and ATP release, as well as disruption of glutathione redox status. Furthermore, the antioxidant compound glycoursodeoxycholic acid (GUDCA) fully abrogated UCB-induced cytochrome c oxidase inhibition and significantly prevented oxidative stress, metabolic alterations, and cell demise. These results suggest that the neurotoxicity associated with neonatal bilirubin-induced encephalopathy occur through a dysregulation of energy metabolism, and supports the notion that GUDCA may be useful in the treatment of BIND.
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Affiliation(s)
- Ana Rita Vaz
- Centro de Patogénese Molecular - UBMBE/iMed.UL, Faculdade de Farmácia, University of Lisbon, Lisbon, Portugal
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26
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Hayashida M, Miyaoka T, Tsuchie K, Yasuda H, Wake R, Nishida A, Inagaki T, Toga T, Nagami H, Oda T, Horiguchi J. Hyperbilirubinemia-related behavioral and neuropathological changes in rats: a possible schizophrenia animal model. Prog Neuropsychopharmacol Biol Psychiatry 2009; 33:581-8. [PMID: 19249333 DOI: 10.1016/j.pnpbp.2009.02.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Revised: 02/05/2009] [Accepted: 02/06/2009] [Indexed: 11/20/2022]
Abstract
BACKGROUND Patients with schizophrenia show a significantly higher frequency of hyperbilirubinemia than patients suffering from other psychiatric disorders and the general healthy population. We examined the hyperbilirubinemia on behavioral and neuropathological changes in rats as a possible animal model of schizophrenia. METHODS Gunn rats with severe hyperbilirubinemia (j/j), Gunn rats without severe hyperbilirubinemia (+/j), and Wistar rats were examined by open-field, social interaction, and prepulse inhibition tests. TUNEL, AgNOR and Ki-67 were also assayed on paraffin-embedded brain sections of these rats. RESULTS Compared to Wistar rats, both Gunn j/j and +/j rats showed hyperlocomotion, high sniffing scores, and low defecation scores. They showed significantly more aggressive behaviors and impaired prepulse inhibition. The numbers of Ki-67-labeled cells and AgNOR were lower and the number of TUNEL-positive cells was higher than that of Wistar rats. CONCLUSIONS These results might support the neurodevelopmental hypothesis of schizophrenia. Both Gunn j/j and +/j rats may be a useful animal model and provide clues to the role of hyperbilirubinemia in schizophrenia.
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Affiliation(s)
- Maiko Hayashida
- Department of Psychiatry, Shimane University Faculty of Medicine, Japan
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27
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Chang FY, Lee CC, Huang CC, Hsu KS. Unconjugated bilirubin exposure impairs hippocampal long-term synaptic plasticity. PLoS One 2009; 4:e5876. [PMID: 19517010 PMCID: PMC2690688 DOI: 10.1371/journal.pone.0005876] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Accepted: 05/14/2009] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Jaundice is one of the most common problems encountered in newborn infants, due to immaturity of hepatic conjugation and transport processes for bilirubin. Although the majority of neonatal jaundice is benign, some neonates with severe hyperbilirubinemia develop bilirubin encephalopathy or kernicterus. Accumulation of unconjugated bilirubin (UCB) in selected brain regions may result in temporary or permanent impairments of auditory, motor, or cognitive function; however, the molecular mechanisms by which UCB elicits such neurotoxicity are still poorly understood. The present study is undertaken to investigate whether prolonged exposure of rat organotypic hippocampal slice cultures to UCB alters the induction of long-term synaptic plasticity. METHODOLOGY/PRINCIPAL FINDINGS Using electrophysiological recording techniques, we find that exposure of hippocampal slice cultures to clinically relevant concentrations of UCB for 24 or 48 h results in an impairment of CA1 long-term potentiation (LTP) and long-term depression (LTD) induction in a time- and concentration-dependent manner. Hippocampal slice cultures stimulated with UCB show no changes in the secretion profiles of the pro-inflammatory cytokines, interleukin-1beta and tumor necrosis factor-alpha, or the propidium ioide uptake. UCB treatment produced a significant decrease in the levels of NR1, NR2A and NR2B subunits of N-methyl-D-aspartate (NMDA) receptors through a calpain-mediated proteolytic cleavage mechanism. Pretreatment of the hippocampal slice cultures with NMDA receptor antagonist or calpain inhibitors effectively prevented the UCB-induced impairment of LTP and LTD. CONCLUSION/SIGNIFICANCE Our results indicate that the proteolytic cleavage of NMDA receptor subunits by calpain may play a critical role in mediating the UCB-induced impairment of long-term synaptic plasticity in the hippocampus. These observations provide new insights into the molecular mechanisms underlying UCB-induced impairment of hippocampal synaptic plasticity which, in turn, might provide opportunities for the development of novel therapeutic strategies that targets these pathways for treatment.
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Affiliation(s)
- Fang-Yu Chang
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Cheng-Che Lee
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Chiung-Chun Huang
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Kuei-Sen Hsu
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Center for Gene Regulation and Signal Transduction Research, National Cheng Kung University, Tainan, Taiwan
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Berns M, Toennessen M, Koehne P, Altmann R, Obladen M. Ibuprofen augments bilirubin toxicity in rat cortical neuronal culture. Pediatr Res 2009; 65:392-6. [PMID: 19127220 DOI: 10.1203/pdr.0b013e3181991511] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Premature infants are at risk for bilirubin-associated brain damage. In cell cultures bilirubin causes neuronal apoptosis and necrosis. Ibuprofen is used to close the ductus arteriosus, and is often given when hyperbilirubinemia is at its maximum. Ibuprofen is known to interfere with bilirubin-albumin binding. We hypothesized that bilirubin toxicity to cultured rat embryonic cortical neurons is augmented by coincubation with ibuprofen. Incubation with ibuprofen above a concentration of 125 microg/mL reduced cell viability, measured by methylthiazole tetrazolium reduction, to 68% of controls (p < 0.05). Lactate dehydrogenase (LDH) release increased from 29 to 38% (p < 0.01). The vehicle solution did not affect cell viability. Coincubation with 10 microM unconjugated bilirubin (UCB)/human serum albumin in a molar ratio of 3:1 and 250 microg/mL ibuprofen caused additional loss of cell viability and increased LDH release (p < 0.01), DNA fragmentation, and activated caspase-3. Preincubation with the pan-caspase inhibitor z-val-ala-asp-fluoromethyl ketone abolished ibuprofen- and UCB-induced DNA fragmentation. The study demonstrates that bilirubin in low concentration of 10 microM reduces neuron viability and ibuprofen increases this effect. Apoptosis is the underlying cell death mechanism.
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Affiliation(s)
- Monika Berns
- Department of Neonatology, Charité-Universitätsmedizin Berlin, Berlin 13353, Germany.
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29
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Ah YM, Kim YM, Kim MJ, Choi YH, Park KH, Son IJ, Kim SG. Drug-induced Hyperbilirubinemia and the Clinical Influencing Factors. Drug Metab Rev 2008; 40:511-37. [DOI: 10.1080/03602530802341133] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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30
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Joseph A, Antony S, Paulose C. Increased glutamate receptor gene expression in the cerebral cortex of insulin induced hypoglycemic and streptozotocin-induced diabetic rats. Neuroscience 2008; 156:298-304. [DOI: 10.1016/j.neuroscience.2008.07.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2008] [Revised: 07/03/2008] [Accepted: 07/08/2008] [Indexed: 11/24/2022]
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Shapiro SM, Sombati S, Geiger A, Rice AC. NMDA channel antagonist MK-801 does not protect against bilirubin neurotoxicity. Neonatology 2007; 92:248-57. [PMID: 17556843 DOI: 10.1159/000103743] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2006] [Accepted: 02/05/2007] [Indexed: 11/19/2022]
Abstract
BACKGROUND Bilirubin encephalopathy or kernicterus is a potentially serious complication of neonatal hyperbilirubinemia. The mechanism of bilirubin-induced neurotoxicity is not known. Many neurological insults are mediated through NMDA receptor activation. OBJECTIVE We assessed the effect of the NMDA channel antagonist, MK-801 on bilirubin neurotoxicity in vivo and in vitro. METHODS Bilirubin toxicity in vitro was assessed using trypan blue staining. Sulfadimethoxine injected (i.p.) jaundiced Gunn rat pups exhibit many neurological sequelae observed in human hyperbilirubinemia. Brainstem auditory-evoked potentials (BAEPs), a noninvasive sensitive tool to assess auditory dysfunction due to bilirubin neurotoxicity, were used to assess neuroprotection with MK-801 (i.p.) in vivo. RESULTS In primary cultures of hippocampal neurons, 20 min exposure to 64:32 microM bilirubin:human serum albumin reduced the cell viability by approximately 50% ten hours later. MK-801 treatment did not protect the cells. MK-801 pretreatment doses ranging from 0.1-4.0 mg/kg did not protect against BAEP abnormalities in Gunn rat pups 6 h after sulfadimethoxine injection. CONCLUSION Our findings suggest that bilirubin neurotoxicity is not mediated through NMDA receptor activation.
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MESH Headings
- Animals
- Animals, Newborn
- Anti-Infective Agents
- Bilirubin/adverse effects
- Cell Survival/drug effects
- Cell Survival/physiology
- Disease Models, Animal
- Dizocilpine Maleate/pharmacology
- Dose-Response Relationship, Drug
- Evoked Potentials, Auditory, Brain Stem/drug effects
- Evoked Potentials, Auditory, Brain Stem/physiology
- Hyperbilirubinemia/chemically induced
- Hyperbilirubinemia/complications
- Hyperbilirubinemia/physiopathology
- Jaundice/chemically induced
- Jaundice/complications
- Jaundice/physiopathology
- Kernicterus/etiology
- Kernicterus/physiopathology
- Kernicterus/prevention & control
- Neurons/drug effects
- Neurons/physiology
- Neuroprotective Agents/pharmacology
- Rats
- Rats, Gunn
- Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors
- Receptors, N-Methyl-D-Aspartate/physiology
- Sulfadimethoxine
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Affiliation(s)
- Steven M Shapiro
- Department of Neurology, Virginia Commonwealth University, Richmond, VA 23298-0599, USA
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32
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Hankø E, Hansen TWR, Almaas R, Rootwelt T. Recovery after short-term bilirubin exposure in human NT2-N neurons. Brain Res 2006; 1103:56-64. [PMID: 16814266 DOI: 10.1016/j.brainres.2006.05.083] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2005] [Revised: 05/13/2006] [Accepted: 05/17/2006] [Indexed: 11/25/2022]
Abstract
We used human NT2-N neurons to investigate delayed effects of short-term exposure to unconjugated bilirubin (UCB). Cell viability was evaluated with MTT reduction assays and nuclear morphology. A 6-h exposure to 1, 5, or 25 microM UCB and serum deprivation (SED) significantly diminished MTT reduction. 96 h after rescue of neurons with removal of UCB and re-incubation in the original serum-containing medium, delayed effects were evident as recovery (1 microM UCB), intermediate cell death (5 microM UCB), or near complete cell death (25 microM UCB). The impact of 6 h of SED alone appeared to be modest in rescued neurons. In this model, co-treatment with the specific caspase-3 inhibitor, zDEVD.FMK (100 microM), or the pancaspase inhibitor zVAD.FMK (100 microM) did not improve viability in rescued neurons exposed to 5 microM UCB, while treatment with the NMDA receptor antagonist MK-801 (1 microM) enhanced the number of undamaged nuclei (86 +/- 14% versus 50 +/- 12%, P = 0.001). MK-801 had, however, no impact on MTT reduction. In a different model with a 102-h continuous exposure to UCB and SED, we found a significant additional toxic impact of serum deprivation. Separate experiments suggested that this was a result of late caspase-mediated toxicity. We conclude that UCB-mediated effects may be reversible in this model. Blockade of excitotoxic mechanisms, but not caspase activity may prevent delayed cell death.
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Affiliation(s)
- Erik Hankø
- Department of Pediatric Research, Rikshospitalet-Radiumhospitalet Medical Center, University of Oslo, Oslo, Norway.
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33
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Tastekin A, Gepdiremen A, Ors R, Buyukokuroglu ME, Halici Z. Protective effect of L-carnitine against bilirubin-induced neuronal cell death. Brain Dev 2006; 28:436-9. [PMID: 16516423 DOI: 10.1016/j.braindev.2006.01.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2005] [Revised: 01/19/2006] [Accepted: 01/20/2006] [Indexed: 10/25/2022]
Abstract
There is growing evidence that glutamate receptor-mediated injury plays a crucial role in bilirubin neurotoxicity. L-carnitine (LC) has been shown to prevent glutamate-induced toxicity in neuronal cell culture. The purpose of this study is to assess whether LC is able to prevent bilirubin neurotoxicity. Unconjugated bilirubin at different concentrations was administered to cerebellar granular cell cultures prepared from 1-day-old Sprague-Dawley rats. The neuroprotective effect of LC was examined. LC at doses of 10(-6), 10(-5), 10(-4) and 10(-3) M was applied to culture flasks. LC at a dose of 10(-4) M significantly blocked bilirubin neurotoxicity. On the other hand, LC significantly increased bilirubin toxicity at a higher dose (10(-3) M). LC at the doses of 10(-5) and 10(-6) M was found to be ineffective. 10(-4) M LC decreased bilirubin-induced neuronal cell death from 47.72+/-3.68 to 27.23+/-5.14%, (P=0.003). The present study demonstrates, for the first time, that LC protects against bilirubin neurotoxicity in a dose-dependent manner in cerebellar granular cell culture of rats. Further research is needed to confirm our findings and to clarify the mechanisms responsible for the protective effect of LC.
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Affiliation(s)
- Ayhan Tastekin
- Division of Neonatology, School of Medicine, Atatürk University, Erzurum, Turkey.
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34
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Abstract
This article describes new findings concerning the basic science of bilirubin neurotoxicity, new considerations of the definition of clinical kernicterus, and new and useful tools to diagnose kernicterus in older children, and discusses treatments for kernicterus beyond the newborn period and why proper diagnosis is important.
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Affiliation(s)
- Steven M Shapiro
- Division of Child Neurology, Department of Neurology, Virginia Commonwealth University Medical Center, Virginia Commonwealth University, Richmond, 23298-0211, USA.
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Hankø E, Hansen TWD, Almaas R, Paulsen R, Rootwelt T. Synergistic protection of a general caspase inhibitor and MK-801 in bilirubin-induced cell death in human NT2-N neurons. Pediatr Res 2006; 59:72-7. [PMID: 16326984 DOI: 10.1203/01.pdr.0000191135.63586.08] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Unconjugated bilirubin (UCB) induces both apoptosis and necrosis in neurons. To investigate the role of caspases and excitotoxicity in UCB-induced cell death, we exposed NT2-N neurons to 5 microM UCB (a concentration known to induce apoptosis) or 2 microM staurosporine (positive apoptosis control) and investigated the effects of treatments with the specific caspase-3 inhibitor, zDEVD.FMK (20 and 100 microM), or the general caspase inhibitor, zVAD.FMK (20 and 100 microM), and/or the N-methyl-D-aspartate (NMDA) receptor antagonist MK-801 (10 microM) during a 24- or 48-h exposure. UCB increased caspase-3 activity 2.3-fold after 6 h. Despite this, treatment with zDEVD.FMK did not prevent cell death. zVAD.FMK enhanced neuronal survival by reducing apoptotic nuclear fragmentation, while MK-801 enhanced survival by reducing apoptotic nuclear condensation; both without affecting the MTT assays. Combined treatment reduced both apoptotic morphologies (without affecting necrosis), and this effect was also reflected in the MTT assays [corrected] We conclude that NMDA receptor-mediated pathways and caspase-mediated pathways are involved in UCB-induced cell death in human NT2-N neurons. Concomitant inhibition of both pathways results in synergistic protection.
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Affiliation(s)
- Erik Hankø
- Department of Pediatric Research, Riskhospitalet-Radiumhospitalet University Hospital, University of Oslo, Norway.
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36
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Tiribelli C, Ostrow JD. The molecular basis of bilirubin encephalopathy and toxicity: report of an EASL Single Topic Conference, Trieste, Italy, 1-2 October, 2004. J Hepatol 2005; 43:156-66. [PMID: 15921815 DOI: 10.1016/j.jhep.2005.04.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Claudio Tiribelli
- Centro Studi Fegato, Bldg. Q, AREA Science Park, Basovizza and Department of BBCM, University of Trieste, 34012 Trieste, Italy.
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37
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Brito MA, Brites D, Butterfield DA. A link between hyperbilirubinemia, oxidative stress and injury to neocortical synaptosomes. Brain Res 2004; 1026:33-43. [PMID: 15476695 DOI: 10.1016/j.brainres.2004.07.063] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/31/2004] [Indexed: 11/28/2022]
Abstract
Cytotoxicity by unconjugated bilirubin involves disturbances of membrane structure, excitotoxicity and cell death. These events were reported to trigger elevated free radicals production and impairment of calcium homeostasis, and to result in loss of cell membrane integrity. Therefore, this study was designed to investigate whether interaction of clinically relevant concentrations of free unconjugated bilirubin with synaptosomal membrane vesicles could be linked to oxidative stress, cytosolic calcium accumulation and perturbation of membrane function. Synaptosomal vesicles were prepared from gerbil cortical brain tissue and incubated with purified bilirubin (<or=1 microM), for 4 h at 37 degrees C. Intracellular concentrations of reactive oxygen species (ROS) and calcium were determined by dichlorofluorescin and BAPTA fluorescent probes, respectively. Membrane protein and lipid oxidation were evaluated by immunocytochemistry and phosphatidylserine exposure by annexin V binding. Levels of reduced and oxidized glutathione (GSH and GSSG, respectively), as well as activities of Mg(2+)-ATPase aminophospholipid translocase (flippase) and Na(+),K(+)-ATPase, were also measured. Our results showed that bilirubin induced oxidative stress, due to a rise in lipid (>or=10%, P<0.05) and protein oxidation (>or=20%, P<0.01), ROS content (approximately 17%, P<0.01), and a decrease in GSH/GSSG ratio (>30%, P<0.01). In addition, synaptosomes exposed to bilirubin exhibited increased externalization of phosphatidylserine (approximately 10%, P<0.05), together with decreased flippase and NA(+),K(+)-ATPase (>or=15%, P<0.05) activities, events that were accompanied by enhanced intracellular calcium levels ( approximately 20%, P<0.01). The data obtained point out that interaction of unconjugated bilirubin with synaptosomal membrane vesicles leads to oxidative injury, loss of membrane asymmetry and functionality, and calcium intrusion, thus potentially contributing to the pathogenesis of encephalopathy by hyperbilirubinemia.
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Affiliation(s)
- Maria Alexandra Brito
- Centro de Patogénese Molecular--UBMBE, Faculdade de Farmácia, University of Lisbon, Av. das Forças Armadas, 1600-083 Lisbon, Portugal.
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38
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Abstract
The metabolism of the basal ganglia was examined by using proton magnetic resonance spectroscopy in 5 neonates with severe hyperbilirubinemia. A decreased N-acetylaspartate/choline ratio, indicating neuronal injury, and an abnormally high lactate/N-acetylaspartate ratio were found only in the neonate with neonatal magnetic resonance imaging abnormalities and subsequent cerebral palsy.
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Affiliation(s)
- Floris Groenendaal
- Department of Neonatology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, Netherlands.
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39
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Abstract
Plasma levels of ionized magnesium (IMg) measured by ion-selective electrode were investigated in neonatal hyperbilirubinemia by comparing the newborns with (> or =205 microM) and without (<205 microM) significant hyperbilirubinemia (groups of severe and moderate hyperbilirubinemia, respectively). Serum bilirubin, plasma IMg, and ionized calcium (ICa) levels were determined in 165 healthy term newborns with nonhemolytic indirect hyperbilirubinemia during the first 10 d of life. Mean serum bilirubin, plasma IMg, and ICa levels were 200.1 +/- 126.5 microM, 0.54 +/- 0.12 mM, and 1.15 +/- 0.12 mM, respectively, in 165 newborns whose mean postnatal age was 156.1 +/- 46.5 h, and there was a significant positive correlation between the mean serum bilirubin and plasma IMg levels (r = 0.535, p < 0.001). Serum bilirubin levels (304.4 +/- 83.8 microM versus 94.1 +/- 54.7 microM) and plasma IMg levels (0.6 +/- 0.12 mM versus 0.49 +/- 0.1 mM) were significantly higher and plasma ICa levels (1.13 +/- 0.12 mM versus 1.18 +/- 0.12 mM) were significantly lower in the group of severe hyperbilirubinemia (n = 83) when compared with the group with moderate hyperbilirubinemia (n = 82). Seventeen of the 83 cases of severe hyperbilirubinemia had IMg levels above the normal range (> or =0.69 mM), whereas none of the 82 cases of moderate hyperbilirubinemia had elevated IMg levels. Fifteen of the 17 with high IMg levels had bilirubin levels >290 microM. Results of the present study suggest that increase in plasma IMg may be due to extracellular movement of Mg, a principally intracellular ion, resulting from generalized cellular injury including neurons and erythrocytes. Considering neuroprotective functions and beneficial effects of Mg ion in improving neurologic outcome, we also may speculate the possibility of a neuroprotective role or a compensatory mechanism in IMg increase against emerging toxicity risk of increasing serum bilirubin levels.
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Affiliation(s)
- S Umit Sarici
- Department of Pediatrics, Hacettepe University Faculty of Medicine Ihsan Dogramact Children's Hospital, Ankara, Turkey.
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40
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Lin S, Yan C, Wei X, Paul SM, Du Y. p38 MAP kinase mediates bilirubin-induced neuronal death of cultured rat cerebellar granule neurons. Neurosci Lett 2003; 353:209-12. [PMID: 14665418 DOI: 10.1016/j.neulet.2003.09.053] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Brain damage induced by unconjugated bilirubin, the end product of heme catabolism, in human neonates is a well recognized clinical syndrome. However, the cellular and molecular mechanisms underlying bilirubin neurotoxicity remain unclear. To characterize the sequence of events leading to bilirubin-induced neurotoxicity, we have exposed rat cerebellar granule neurons (CGN) to bilirubin and investigated whether activation of p38 MAP kinase mediates neuronal death. In this study, bilirubin markedly induces an early activation of p38 MAP kinase at 1 h. Pretreatment of neurons with a p38 MAP kinase inhibitor, SB 203580, significantly protected CGN against bilirubin-induced neurotoxicity. Our data suggest that hyperphosphorylation of p38 MAP kinase plays an important role in bilirubin-induced neuronal death and provides a novel approach to discovering drugs to treat bilirubin-induced encephalopathy.
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Affiliation(s)
- Suizhen Lin
- Department of Neurology, School of Medicine, Indiana University, Indianapolis, IN 46202, USA
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41
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Affiliation(s)
- Jean-Michel Hascoet
- Neonatology Department, Maternite Regionale Universitaire, 10 rue du 54042 Nancy, France.
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42
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Grojean S, Vert P, Daval JL. Combined effects of bilirubin and hypoxia on cultured neurons from the developing rat forebrain. Semin Perinatol 2002; 26:416-24. [PMID: 12537313 DOI: 10.1053/sper.2002.37141] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Hyperbilirubinemia and hypoxia are common causes of brain injury in the newborn. To determine the effects of free bilirubin associated with transient hypoxia on developing rat neurons, the cells were exposed to bilirubin (0.25 to 5 micromol/L) and/or to hypoxia for 3 or 6 hours (95% N2-5% CO2). Glutamate receptor antagonists were added to some cultures. Cell death characteristics, energy metabolism, and protein synthesis were analyzed for 96 hours. Bilirubin increased apoptotic cell death. When associated with hypoxia, the neuronal loss was worsened. Bilirubin reduced energy metabolism, whereas a 6-hour exposure to hypoxia increased it for at least 24 hours, with no influence of additional bilirubin. Bilirubin with or without hypoxia induced 2 increases in protein synthesis, at 1 and 72 hours. In this model, bilirubin may promote programmed neuronal death. When bilirubin is associated with hypoxia, the deleterious effects are enhanced. The suppression of bilirubin induced neuronal damage by the NMDA (N-methyl-D-aspartate) receptor antagonist MK801 suggests the involvement of glutamate.
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Affiliation(s)
- Stéphanie Grojean
- Laboratoire de Biologie du developpement humain Université Henri Poincaré Nancy, France
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43
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Abstract
Auditory neuropathy (AN) is a disorder characterized by the absence or the severe impairment of the auditory brainstem responses (ABRs) together with the preservation of otoacoustic emissions and/or cochlear microphonic (CM). We recorded transtympanic electrocochleography (ECohG) evoked by 0.1 ms clicks in one young adult and in four children having distortion product otoacoustic emissions and absent ABRs. In all but one patient CM and summating potential (SP) were present with normal threshold, and their amplitudes appeared comparable to or higher than the values obtained from subjects with normal hearing. The compound action potential (CAP) was absent in two patients while in one subject CM and SP were followed by a highly desynchronized neural activity. A broad CAP was found in two children and the threshold appeared clearly elevated in one of them, while it showed only a mild elevation in the other. No correlation was found between CAP and behavioral thresholds. These results suggest that ECohG can be useful in AN diagnoses since it is the only reliable tool in evaluating the auditory peripheral function in the presence of a desynchronized ABR.
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Affiliation(s)
- Rosamaria Santarelli
- Department of Medical and Surgical Specialities, Audiology and Phoniatric Service, University of Padova, Via Giustiniani 2, I-35128, Padua, Italy.
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44
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Rodrigues CMP, Solá S, Brites D. Bilirubin induces apoptosis via the mitochondrial pathway in developing rat brain neurons. Hepatology 2002; 35:1186-95. [PMID: 11981769 DOI: 10.1053/jhep.2002.32967] [Citation(s) in RCA: 128] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Increased levels of unconjugated bilirubin, the end-product of heme catabolism, are detrimental to the central nervous system. To examine the role of apoptosis in bilirubin-induced toxicity and to characterize the biochemical pathway of cell death, we exposed developing rat brain neurons to purified unconjugated bilirubin at concentrations below and above saturation of human serum albumin. Isolated neurons treated with bilirubin showed increased levels of apoptosis. Mitochondrial cytochrome c was extensively released and accumulated in cytosol. Consistent with this observation, caspase-3 was activated and the full-length substrate poly(ADP)ribose polymerase (PARP) degraded, even in the presence of very modestly elevated concentrations of bilirubin. In parallel, all events were prevented in cells preincubated with ursodeoxycholate. Further experiments showed that bilirubin diminished mitochondrial transmembrane potential (DeltaPsi(m)) and increased mitochondrial-associated Bax protein levels, while directly disrupting membrane lipid and protein structure. In conclusion, bilirubin induces mitochondrial depolarization and Bax translocation via physical interaction with membranes, mediating the mitochondrial pathway of apoptosis in neurons exposed to bilirubin. These results provide a novel insight into the mechanism of bilirubin-induced toxicity.
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Affiliation(s)
- Cecília M P Rodrigues
- Centro de Patogénese Molecular, Faculdade de Farmácia, University of Lisbon, Lisbon, Portugal.
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45
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Silva RFM, Rodrigues CMP, Brites D. Rat cultured neuronal and glial cells respond differently to toxicity of unconjugated bilirubin. Pediatr Res 2002; 51:535-41. [PMID: 11919342 DOI: 10.1203/00006450-200204000-00022] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
High levels of unconjugated bilirubin (UCB) can be neurotoxic. Nevertheless, the mechanism of UCB interaction with neural cells is still unknown. This study investigates whether cultured rat neurons and astrocytes respond differently to UCB exposure. UCB toxicity was evaluated by lactate dehydrogenase release, induction of apoptosis, cytoskeleton degeneration, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction, and glutamate uptake. Primary cultures of rat brain astrocytes and neurons were incubated at 37 degrees C with 85.5 microM UCB plus 28.5 microM albumin for 4 h. In assays of glutamate uptake, cells were exposed to 80-120 microM UCB plus 100 microM albumin for 15 min. The results showed that after incubation with 85.5 microM UCB, lactate dehydrogenase release was greater in neurons than in astrocytes (38% versus 14%, p < 0.05). Also, levels of apoptosis were markedly enhanced in neurons (29% versus 19%, p < 0.01). In accordance, neuronal cytoskeleton disassembly was evident during incubation with 85.5 microM UCB, whereas equivalent effects on astrocytes required as much as 171 microM. Conversely, inhibition of MTT metabolism and glutamate uptake by UCB was more pronounced in astrocytes than in neurons (74% versus 60%, p < 0.05 and 41% to 56% versus 25% to 33%, p < 0.05, respectively). In conclusion, the study demonstrates that astrocytes are more susceptible to inhibition of glutamate uptake and MTT reduction by UCB, whereas neurons are more sensitive to cell death by necrosis or apoptosis. These results suggest that UCB is toxic to both astrocytes and neurons, although through distinct pathways.
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Affiliation(s)
- Rui F M Silva
- Centro de Patogénese Molecular, Faculdade de Farmácia, University of Lisbon, Lisbon, Portugal
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46
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Affiliation(s)
- Adam Jonas
- Department of Pediatrics, Harbor-UCLA Medical Center, Torrance, CA, U.S.A
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47
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Park WS, Chang YS, Chung SH, Seo DW, Hong SH, Lee M. Effect of hypothermia on bilirubin-induced alterations in brain cell membrane function and energy metabolism in newborn piglets. Brain Res 2001; 922:276-81. [PMID: 11743960 DOI: 10.1016/s0006-8993(01)03186-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The aim of this study was to evaluate the effects of hypothermia on bilirubin-induced alterations in brain cell membrane function and energy metabolism in the developing brain. Thirty-seven newborn piglets were divided randomly into four groups: normothermic control (NC, n=9); hypothermic control (HC, n=7); normothermic bilirubin infusion (NB, n=11); and hypothermic bilirubin infusion (HB, n=10) groups. In bilirubin infusion groups (NB and HB), a loading dose of bilirubin (35 mg/kg) was given over 5 min, followed by a continuous infusion (25 mg/kg/h) for 4 h. The control groups (NC, HC) received a bilirubin-free buffer solution. Sulfadimethoxine was administered to animals in all experimental groups. Rectal temperature was maintained between 38.0 and 39.0 degrees C in normothermic groups, and between 34.0 and 35.0 degrees C in hypothermic groups for 4 h after the start of bilirubin infusion. The final blood and brain bilirubin concentrations in the bilirubin infusion groups (NB and HB) were not significantly different. Decreased cerebral cortical cell membrane Na(+),K(+)-ATPase activity and increased lipid peroxidation products observed in the NB group, indicative of bilirubin-induced brain damage, were significantly attenuated in the HB group. Hypothermia also significantly improved the bilirubin-induced reduction in brain ATP and phosphocreatine levels and increase in blood and brain lactate levels. In summary, hypothermia significantly attenuated the bilirubin-induced alterations in brain cell membrane function and energy metabolism in the newborn piglet. These findings suggest the possibility that hypothermia could be a good neuroprotective therapeutic modality in neonatal bilirubin encephalopathy.
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Affiliation(s)
- W S Park
- Department of Pediatrics, Samsung Medical Center, 50 Ilwon-Dong, Kangnam-Gu, Sungkyunkwan University School of Medicine, Seoul, South Korea
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48
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Abstract
Brain tissue has a remarkable ability to accumulate glutamate. This ability is due to glutamate transporter proteins present in the plasma membranes of both glial cells and neurons. The transporter proteins represent the only (significant) mechanism for removal of glutamate from the extracellular fluid and their importance for the long-term maintenance of low and non-toxic concentrations of glutamate is now well documented. In addition to this simple, but essential glutamate removal role, the glutamate transporters appear to have more sophisticated functions in the modulation of neurotransmission. They may modify the time course of synaptic events, the extent and pattern of activation and desensitization of receptors outside the synaptic cleft and at neighboring synapses (intersynaptic cross-talk). Further, the glutamate transporters provide glutamate for synthesis of e.g. GABA, glutathione and protein, and for energy production. They also play roles in peripheral organs and tissues (e.g. bone, heart, intestine, kidneys, pancreas and placenta). Glutamate uptake appears to be modulated on virtually all possible levels, i.e. DNA transcription, mRNA splicing and degradation, protein synthesis and targeting, and actual amino acid transport activity and associated ion channel activities. A variety of soluble compounds (e.g. glutamate, cytokines and growth factors) influence glutamate transporter expression and activities. Neither the normal functioning of glutamatergic synapses nor the pathogenesis of major neurological diseases (e.g. cerebral ischemia, hypoglycemia, amyotrophic lateral sclerosis, Alzheimer's disease, traumatic brain injury, epilepsy and schizophrenia) as well as non-neurological diseases (e.g. osteoporosis) can be properly understood unless more is learned about these transporter proteins. Like glutamate itself, glutamate transporters are somehow involved in almost all aspects of normal and abnormal brain activity.
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Affiliation(s)
- N C Danbolt
- Department of Anatomy, Institute of Basic Medical Sciences, University of Oslo, P.O. Box 1105, Blindern, N-0317, Oslo, Norway
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49
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Grojean S, Lievre V, Koziel V, Vert P, Daval JL. Bilirubin exerts additional toxic effects in hypoxic cultured neurons from the developing rat brain by the recruitment of glutamate neurotoxicity. Pediatr Res 2001; 49:507-13. [PMID: 11264434 DOI: 10.1203/00006450-200104000-00012] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Both hypoxia and bilirubin are common risk factors in newborns, which may act synergistically to produce anatomical and functional disturbances of the CNS. Using primary cultures of neurons from the fetal rat brain, it was recently reported that neuronal apoptosis accounts for the deleterious consequences of these two insults. To investigate the influence of hypoxia, bilirubin, or their combination on the outcome of neuronal cells of the immature brain, and delineate cellular mechanisms involved, 6-d-old cultured neurons were submitted to either hypoxia (6 h), unconjugated bilirubin (0.5 microM), or to combined conditions. Within 96 h, cell viability was reduced by 22.7% and 24.5% by hypoxia and bilirubin, respectively, whereas combined treatments decreased vital score by 34%. Nuclear morphology revealed 13.4% of apoptotic cells after hypoxia, 16.2% after bilirubin, and 22.6% after both treatments. Bilirubin action was specifically blocked by the glutamate receptor antagonist MK-801, which was without effect on the consequences of hypoxia. Temporal changes in [(3)H]leucine incorporation rates as well as beneficial effects of cycloheximide reflected a programmed phenomenon dependent upon synthesis of selective proteins. The presence of bilirubin reduced hypoxia-induced alterations of cell energy metabolism, as reflected by 2-D-[(3)H]deoxyglucose incorporation, raising the question of free radical scavenging. Measurements of intracellular radical generation, however, failed to confirm the antioxidant role of bilirubin. Taken together, our data suggest that low levels of bilirubin may enhance hypoxia effects in immature neurons by facilitating glutamate-mediated apoptosis through the activation of N:-methyl-D-aspartate receptors.
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Affiliation(s)
- S Grojean
- Université Henri Poincaré-Nancy 1, 24-30 rue Lionnois, B.P. 3069, 54013 Nancy Cédex, France
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50
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Affiliation(s)
- P A Dennery
- Department of Neonatology, Stanford University School of Medicine, Calif, USA.
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