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Tong XY, Norenberg MD, Paidas MJ, Shamaladevi N, Salgueiro L, Jaszberenyi M, John B, Hussain H, El Hiba O, Abdeljalil EG, Bilal EM, Natarajan S, Romaguera R, Papayan S, Carden AK, Ramamoorthy R, Elumalai N, Schally AV, Nithura J, Patrizio R, Jayakumar AR. Mechanism of Alzheimer type II astrocyte development in hepatic encephalopathy. Neurochem Int 2024; 180:105866. [PMID: 39369794 DOI: 10.1016/j.neuint.2024.105866] [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: 05/14/2024] [Revised: 09/19/2024] [Accepted: 09/22/2024] [Indexed: 10/08/2024]
Abstract
Type C hepatic encephalopathy (Type C HE) is a major and complex neurological condition that occurs following chronic liver failure. The molecular basis of Type C HE remains elusive. Type C HE is characterized by mental confusion, cognitive and motor disturbances. The presence of Alzheimer type II astrocytes (AT2A) is the key histopathological finding observed in Type C HE. However, nothing is currently known regarding AT2A development and its involvement in cognitive, and motor deficits in Type C HE. We, therefore, examined in rats the mechanisms by which liver failure contributes to the progression of AT2A, and its role in the development of cognitive and motor deficits in thioacetamide (TAA) model of Type C HE. We and others earlier reported increased oxidative/nitrosative stress (ONS), JNK1/2, and cMyc activation in ammonia-treated astrocyte cultures, as well as in brains from chronic liver failure. We now found increased levels of astrocytic glia maturation factor (GMF, a factor strongly implicated in neuroinflammation), as well as various inflammatory factors (IL-1β, TNF-α, IL-6, MMP-3, COX2, CXCL1, and PGE2), and reduced levels of GFAP and increased levels of aggregated nuclear protein Lamin A/C in rat brain cortex post-chronic liver failure. We also found increased levels of GMF and inflammatory factors (MMP-3, COX2, CXCL1, and PGE2) in astrocytes post-ammonia treatment in vitro. Additionally, pharmacological inhibition of upstream signaling of GMF (ONS, JNK1/2, and cMyc) or GMF inhibitors W-7 and trifluoperazine significantly reduced the levels of inflammatory factors, the number of AT2A cells, as well as the cognitive and motor deficits in TAA-treated rats. Increased levels of GMF were also identified in human post-mortem brain sections. These findings strongly suggest that increased levels of astrocytic GMF due to elevated levels of ONS, JNK1/2, and cMyc and the subsequent inflammation contribute to the development of AT2A and the consequent cognitive, and motor deficits in chronic liver failure.
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Affiliation(s)
- Xiao Y Tong
- Department of Pathology, University of Miami School of Medicine, Miami, FL, USA
| | - Michael D Norenberg
- Department of Pathology, University of Miami School of Medicine, Miami, FL, USA
| | - Michael J Paidas
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Miami School of Medicine, Miami, FL, USA; Department of Biochemistry & Molecular Biology, University of Miami School of Medicine, Miami, FL, USA
| | | | - Luis Salgueiro
- General Medical Research, R&D Services, Department of Veterans Affairs, Miami, FL, USA
| | - Miklos Jaszberenyi
- General Medical Research, R&D Services, Department of Veterans Affairs, Miami, FL, USA; Department of Pathophysiology, Faculty of Medicine, University of Szeged, Hungary
| | - Binu John
- General Medical Research, R&D Services, Department of Veterans Affairs, Miami, FL, USA
| | - Hussain Hussain
- Larkin Community Hospital, Department of Internal Medicine and Infectious Disease, Miami, FL, USA
| | - Omar El Hiba
- Laboratory of Anthropogenic, Biotechnology, and Health, Nutritional Physiopathologies, Neuroscience and Toxicology Team, Faculty of Sciences, Chouaib Doukkali University, Av Des facultés, 24000, El Jadida, Morocco; The Hassan First University of Settat, Higher Institute of Health Sciences, Laboratory of Health Sciences and Technology, Morocco
| | - El Got Abdeljalil
- Laboratory of Anthropogenic, Biotechnology, and Health, Nutritional Physiopathologies, Neuroscience and Toxicology Team, Faculty of Sciences, Chouaib Doukkali University, Av Des facultés, 24000, El Jadida, Morocco; The Hassan First University of Settat, Higher Institute of Health Sciences, Laboratory of Health Sciences and Technology, Morocco
| | - El-Mansoury Bilal
- Laboratory of Anthropogenic, Biotechnology, and Health, Nutritional Physiopathologies, Neuroscience and Toxicology Team, Faculty of Sciences, Chouaib Doukkali University, Av Des facultés, 24000, El Jadida, Morocco; The Hassan First University of Settat, Higher Institute of Health Sciences, Laboratory of Health Sciences and Technology, Morocco
| | - Sampath Natarajan
- Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Tamil Nadu, India
| | - Rita Romaguera
- Pathology and Laboratory Medicine, Department of Veterans Affairs, Miami, FL, 33125, USA
| | - Stanislav Papayan
- Pathology and Laboratory Medicine, Department of Veterans Affairs, Miami, FL, 33125, USA
| | - Arianna K Carden
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Miami School of Medicine, Miami, FL, USA
| | - Rajalakshmi Ramamoorthy
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Miami School of Medicine, Miami, FL, USA
| | - Nila Elumalai
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Miami School of Medicine, Miami, FL, USA
| | - Andrew V Schally
- Endocrine, Polypeptide, and Cancer Institute, Department of Veterans Affairs, Miami, FL, 33125, USA
| | | | - Rebecca Patrizio
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Miami School of Medicine, Miami, FL, USA
| | - Arumugam R Jayakumar
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Miami School of Medicine, Miami, FL, USA; General Medical Research, R&D Services, Department of Veterans Affairs, Miami, FL, USA; Neuropathology Section, Veterans Affairs Medical Center, Miami, FL, USA; R&D Services and South Florida VA Foundation for Research and Education Inc, Veterans Affairs Medical Center, Miami, FL, USA.
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Zielonka M, Kölker S, Garbade SF, Gleich F, Nagamani SCS, Gropman AL, Druck AC, Ramdhouni N, Göde L, Hoffmann GF, Posset R. Severity-adjusted evaluation of initial dialysis on short-term health outcomes in urea cycle disorders. Mol Genet Metab 2024; 143:108566. [PMID: 39299137 DOI: 10.1016/j.ymgme.2024.108566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Revised: 08/07/2024] [Accepted: 08/13/2024] [Indexed: 09/22/2024]
Abstract
OBJECTIVE In individuals with urea cycle disorders (UCDs) and neonatal disease onset, extracorporeal detoxification by continuous kidney replacement therapy is considered the therapeutic method of choice in addition to metabolic emergency treatment to resolve hyperammonemic decompensation. However, the indications for the initiation of dialysis are heterogeneously implemented transnationally, thereby hampering our understanding of (optimal) short-term health outcomes. METHODS We performed a retrospective comparative analysis evaluating the therapeutic effects of initial dialysis on survival as well as neurocognitive outcome parameters in individuals with UCDs in comparison to a severity-adjusted non-dialyzed control cohort. Overall, 108 individuals with a severe phenotype of male ornithine transcarbamylase deficiency (mOTC-D), citrullinemia type 1 (CTLN1) and argininosuccinic aciduria (ASA) were investigated by stratification based on a recently established and validated genotype-specific disease prediction model. RESULTS Mortality is associated with the height of initial peak plasma ammonium concentration, but appears to be independent from treatment with initial dialysis in mOTC-D. However, improved survival after initial dialysis was observed in CTLN1, while there was a trend towards improved survival in ASA. In survivors, annual frequency of (subsequent) metabolic decompensations did not differ between the dialyzed and non-dialyzed cohorts. Moreover, treatment with initial dialysis was not associated with improved neurocognitive outcomes. INTERPRETATION The present severity-adjusted comparative analysis reveals that general practice of initial dialysis is neither associated with improved survival in individuals with mOTC-D nor does it differ with regard to the neurocognitive outcome for the investigated UCD subtypes. However, initial dialysis might potentially prove beneficial for survival in CTLN1 and ASA. CLINICAL TRIAL REGISTRATION The UCDC database is recorded at the US National Library of Medicine (https://clinicaltrials.gov).
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Affiliation(s)
- Matthias Zielonka
- Heidelberg University, Medical Faculty Heidelberg, and Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany.
| | - Stefan Kölker
- Heidelberg University, Medical Faculty Heidelberg, and Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Sven F Garbade
- Heidelberg University, Medical Faculty Heidelberg, and Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Florian Gleich
- Heidelberg University, Medical Faculty Heidelberg, and Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Sandesh C S Nagamani
- Department of Molecular and Human Genetics, Baylor College of Medicine and Texas Children's Hospital, Houston, TX, USA
| | - Andrea L Gropman
- Children's National Health System and The George Washington School of Medicine, Washington, DC, USA
| | - Ann-Catrin Druck
- Heidelberg University, Medical Faculty Heidelberg, and Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Nesrine Ramdhouni
- Heidelberg University, Medical Faculty Heidelberg, and Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Laura Göde
- Heidelberg University, Medical Faculty Heidelberg, and Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Georg F Hoffmann
- Heidelberg University, Medical Faculty Heidelberg, and Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Roland Posset
- Heidelberg University, Medical Faculty Heidelberg, and Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany.
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Sepehrinezhad A, Stolze Larsen F, Ashayeri Ahmadabad R, Shahbazi A, Sahab Negah S. The Glymphatic System May Play a Vital Role in the Pathogenesis of Hepatic Encephalopathy: A Narrative Review. Cells 2023; 12:cells12070979. [PMID: 37048052 PMCID: PMC10093707 DOI: 10.3390/cells12070979] [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: 10/19/2022] [Revised: 02/20/2023] [Accepted: 03/21/2023] [Indexed: 04/14/2023] Open
Abstract
Hepatic encephalopathy (HE) is a neurological complication of liver disease resulting in cognitive, psychiatric, and motor symptoms. Although hyperammonemia is a key factor in the pathogenesis of HE, several other factors have recently been discovered. Among these, the impairment of a highly organized perivascular network known as the glymphatic pathway seems to be involved in the progression of some neurological complications due to the accumulation of misfolded proteins and waste substances in the brain interstitial fluids (ISF). The glymphatic system plays an important role in the clearance of brain metabolic derivatives and prevents aggregation of neurotoxic agents in the brain ISF. Impairment of it will result in aggravated accumulation of neurotoxic agents in the brain ISF. This could also be the case in patients with liver failure complicated by HE. Indeed, accumulation of some metabolic by-products and agents such as ammonia, glutamine, glutamate, and aromatic amino acids has been reported in the human brain ISF using microdialysis technique is attributed to worsening of HE and correlates with brain edema. Furthermore, it has been reported that the glymphatic system is impaired in the olfactory bulb, prefrontal cortex, and hippocampus in an experimental model of HE. In this review, we discuss different factors that may affect the function of the glymphatic pathways and how these changes may be involved in HE.
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Affiliation(s)
- Ali Sepehrinezhad
- Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran 1449614535, Iran
- Neuroscience Research Center, Mashhad University of Medical Sciences, Mashhad 9919191778, Iran
| | - Fin Stolze Larsen
- Department of Gastroenterology and Hepatology, Rigshospitalet, Copenhagen University Hospital, 999017 Copenhagen, Denmark
| | | | - Ali Shahbazi
- Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran 1449614535, Iran
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran 1449614535, Iran
| | - Sajad Sahab Negah
- Neuroscience Research Center, Mashhad University of Medical Sciences, Mashhad 9919191778, Iran
- Shefa Neuroscience Research Center, Khatam Alanbia Hospital, Tehran 1449614535, Iran
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Colak N, Bayrak Basakci O, Bayram B, Aksay E, Simsek MK, Karabay N. Optic nerve sheath diameter in patients with hepatic encephalopathy. PLoS One 2022; 17:e0277643. [PMID: 36383620 PMCID: PMC9668157 DOI: 10.1371/journal.pone.0277643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 11/01/2022] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND This study aims to reveal whether the optic nerve sheath diameter (ONSD) increases in hepatic encephalopathy (HE) patients, and to determine ONSD is associated with the poor prognosis of patients with HE. METHODS AND MATERIAL In this retrospective case-control study, HE patients who underwent cranial computerized tomography (CT) were included in the case group; and the patients who underwent CT for other reasons for the same age and gender and were normally interpreted were included in the control group. ONSD measurements in the case and control groups and clinical grades of HE with in-hospital mortality and ONSD measurements were compared in the case group. RESULTS This study was done with 74 acute HE patients and 74 control patients. The mean age was 62.9 ± 11.0 years and 67.6% of patients were male in both groups. The ONSD in the case group was higher than the control group (5.27-mm ± 0.82 vs 4.73 mm ± 0.57, p <0.001). In the case group, the ONSD was 5.30 mm ± 0.87 in survivors, and 5.21 ± 0.65 in non-survivors (P = 0.670). There was no significant difference between the West Haven HE grade (P = 0.348) and Child-Pugh Score (P = 0.505) with ONSD measurements. CONCLUSION We have shown that ONSD increases in HE patients compared to the control group. ONSD was not related to the Child-Pugh Score, HE grade, and in-hospital mortality.
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Affiliation(s)
- Nese Colak
- Department of Emergency Medicine, Dokuz Eylül University School of Medicine, Izmir, Turkey
- * E-mail:
| | - Ozlem Bayrak Basakci
- Department of Emergency Medicine, Okan University School of Medicine, Istanbul, Turkey
| | - Basak Bayram
- Department of Emergency Medicine, Dokuz Eylül University School of Medicine, Izmir, Turkey
| | - Ersin Aksay
- Department of Emergency Medicine, Dokuz Eylül University School of Medicine, Izmir, Turkey
| | - Muhammet Kursat Simsek
- Department of Radiology, Manisa Provincial Health Directorate Merkezefendi Public Hospital, Manisa, Turkey
| | - Nuri Karabay
- Department of Radiology, Dokuz Eylül University School of Medicine, Izmir, Turkey
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Rajpurohit S, Musunuri B, Shailesh, Basthi Mohan P, Shetty S. Novel Drugs for the Management of Hepatic Encephalopathy: Still a Long Journey to Travel. J Clin Exp Hepatol 2022; 12:1200-1214. [PMID: 35814520 PMCID: PMC9257922 DOI: 10.1016/j.jceh.2022.01.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 01/24/2022] [Indexed: 12/12/2022] Open
Abstract
Hepatic encephalopathy (HE) is one of the reversible complications of chronic liver disease, associated with a higher mortality rate. In current clinical practice, treatment with rifaximin and lactulose/lactitol is the first line of treatment in HE. With the advance in pathophysiology, a new class of ammonia lowering drugs has been revealed to overcome the hurdle and disease burden. The mechanism of the novel agents differs significantly and includes the alteration in intestinal microbiota, intestinal endothelial integrity, oxidative stress, inflammatory markers, and modulation of neurotoxins. Most of the trials have reported promising results in the treatment and prevention of HE with fecal microbiota transplantation, albumin, probiotics, flumazenil, polyethylene glycol, AST-120, glycerol phenylbutyrate, nitazoxanide, branched-chain amino acid, naloxone, and acetyl-l-carnitine. However, their clinical use is limited due to the presence of major drawbacks in their study design, sample size, safety profile, bias, and heterogenicity. This study will discuss the novel therapeutic targets for HE in liver cirrhosis patients with supporting clinical trial data.
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Key Words
- ALC, acetyl-L-carnitine
- BCAA, branched-chain amino acid
- BD, twice a day
- BDI, Beck Depression Inventory
- BUN, blood urea nitrogen
- CHESS, Clinical Hepatic Encephalopathy Staging Scale
- CLDQ, Chronic Liver Disease Questionnaire
- ECT, estimated completion time
- EEG, electroencephalogram
- FMT, fecal microbiota transplantation
- GPB, glycerol phenylbutyrate
- HESA, Hepatic Encephalopathy Scoring Algorithm
- HRQOL, health-related quality of life
- IV, intravenous
- MED, Modified Encephalopathy Scale
- MELD, Model for End-stage Liver Disease
- MMSE, Mini-Mental State Examination
- NTZ, nitazoxanide
- Nal, naloxone
- OD, once a day
- ORT, object recognition test
- PEG, polyethylene glycol
- QID, four times a day
- QOL, quality of life
- RBNS, Repeatable Battery for the Assessment of Neuropsychological Status
- RCT, randomized control trial
- RT-qPCR, real-time quantitative polymerase chain reaction
- TID, three times a day
- VSL#3, high concentration probiotic preparations
- hepatic encephalopathy
- liver cirrhosis
- novel drugs
- treatment outcome
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Affiliation(s)
- Siddheesh Rajpurohit
- Department of Gastroenterology and Hepatology, Kasturba Medical College, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Balaji Musunuri
- Department of Gastroenterology and Hepatology, Kasturba Medical College, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Shailesh
- Department of Gastroenterology and Hepatology, Kasturba Medical College, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Pooja Basthi Mohan
- Department of Gastroenterology and Hepatology, Kasturba Medical College, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Shiran Shetty
- Department of Gastroenterology and Hepatology, Kasturba Medical College, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
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Mataya LA, Srinivasan V, Rand EB, Alcamo AM. Multiple organ involvement and ICU considerations for the care of acute liver failure (ALF) and acute on chronic liver failure (ACLF) in children. Transl Pediatr 2021; 10:2749-2762. [PMID: 34765498 PMCID: PMC8578785 DOI: 10.21037/tp-20-375] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 02/23/2021] [Indexed: 12/30/2022] Open
Abstract
Liver disease results in approximately 15,000 pediatric hospitalizations per year in the United States and is a significant burden to child health. Major etiologies of liver failure and indications for transplantation in children include: biliary atresia, metabolic/genetic conditions, toxins, infections, tumors, and immune-mediated liver/biliary injury. Children requiring transplantation are placed on the United Network of Organ Sharing waitlist including those with acute liver failure (ALF) and acute on chronic liver failure (ACLF). ALF is a clinical syndrome in which a previously healthy child develops rapid-onset hepatic dysfunction, and becomes critically ill with multiple organ dysfunction within days. ACLF, by contrast, is generally described as an acute decompensation of pre-existing chronic liver disease (CLD) brought on by a precipitating event, with higher risk of mortality. Children with ALF and ACLF receive multidisciplinary care in pediatric intensive care units (ICUs) due to multiple organ system involvement and high risk of decompensation in these patients. The care of these patients requires a holistic approach that addresses the complex interplay between hepatic and extra-hepatic organ systems. This review will define and describe ALF and ACLF in the pediatric population, and outline the effects of ALF and ACLF on individual organ systems with diagnostic and management considerations in the ICU while awaiting liver transplantation.
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Affiliation(s)
- Leslie A Mataya
- Division of Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Vijay Srinivasan
- Division of Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Anesthesiology and Critical Care Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Elizabeth B Rand
- Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Pediatrics, University of Pennsylvania, Philadelphia, PA, USA
| | - Alicia M Alcamo
- Division of Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Anesthesiology and Critical Care Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Markham C, Williams C, Miller C, Grange DK, Davis TK, Remy KE. Continuous Renal Replacement Therapy for Two Neonates With Hyperammonemia. Front Pediatr 2021; 9:732354. [PMID: 34805036 PMCID: PMC8602909 DOI: 10.3389/fped.2021.732354] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 10/07/2021] [Indexed: 11/13/2022] Open
Abstract
Objectives: This study aims to assess the feasibility of using hemofiltration for ammonia clearance in low body weight infants with an inborn error of metabolism. Design: A study of two cases. Setting: Quaternary pediatric hospital (Saint Louis Children's Hospital) NICU and PICU. Patients: Infants <6 months of age with an ICD-9 diagnosis of 270.6 (hyperammonemia). Interventions: Continuous renal replacement therapy (CRRT). Measurements and Main Results: We measure serum ammonia levels over time and the rate of ammonia clearance over time. Continuous renal replacement therapy was more effective than scavenger therapy alone (Ammonul™) for rapid removal of ammonia in low weight infants (as low as 2.5 kg). Conclusions: Continuous renal replacement therapy is technically feasible in low weight infants with severe hyperammonemia secondary to an inborn error of metabolism.
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Affiliation(s)
- Christopher Markham
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, United States
| | - Caroline Williams
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, United States
| | - Cory Miller
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, United States
| | - Dorothy K Grange
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, United States
| | - T Keefe Davis
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, United States
| | - Kenneth E Remy
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, United States.,Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, United States
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Posset R, Kölker S, Gleich F, Okun JG, Gropman AL, Nagamani SCS, Scharre S, Probst J, Walter ME, Hoffmann GF, Garbade SF, Zielonka M. Severity-adjusted evaluation of newborn screening on the metabolic disease course in individuals with cytosolic urea cycle disorders. Mol Genet Metab 2020; 131:390-397. [PMID: 33288448 PMCID: PMC8315358 DOI: 10.1016/j.ymgme.2020.10.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/29/2020] [Accepted: 10/31/2020] [Indexed: 12/25/2022]
Abstract
OBJECTIVE The implementation of newborn screening (NBS) programs for citrullinemia type 1 (CTLN1) and argininosuccinic aciduria (ASA) is subject to controversial debate. The aim of this study was to assess the impact of NBS on the metabolic disease course and clinical outcome of affected individuals. METHODS In 115 individuals with CTLN1 and ASA, we compared the severity of the initial hyperammonemic episode (HAE) and the frequency of (subsequent) HAEs with the mode of diagnosis. Based on a recently established functional disease prediction model, individuals were stratified according to their predicted severe or attenuated phenotype. RESULTS Individuals with predicted attenuated forms of CTLN1 and ASA were overrepresented in the NBS group, while those with a predicted severe phenotype were underrepresented compared to individuals identified after the manifestation of symptoms (SX). Identification by NBS was associated with reduced severity of the initial HAE both in individuals with predicted severe and attenuated phenotypes, while it was not associated with lower frequency of (subsequent) HAEs. Similar results were obtained when including some patients diagnosed presymptomatically (i.e. prenatal testing, and high-risk family screening) in this analysis. CONCLUSION Since one of the major challenges of NBS outcome studies is the potential overrepresentation of individuals with predicted attenuated phenotypes in NBS cohorts, severity-adjusted evaluation of screened and unscreened individuals is important to avoid overestimation of the NBS effect. NBS enables the attenuation of the initial HAE but does not affect the frequency of subsequent metabolic decompensations in individuals with CTLN1 and ASA. Future long-term studies will need to evaluate the clinical impact of this finding, especially with regard to mortality, as well as cognitive outcome and quality of life of survivors.
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Affiliation(s)
- Roland Posset
- Center for Pediatric and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Stefan Kölker
- Center for Pediatric and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Florian Gleich
- Center for Pediatric and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Jürgen G Okun
- Center for Pediatric and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Andrea L Gropman
- Children's National Health System and The George Washington School of Medicine, Washington, DC, USA
| | - Sandesh C S Nagamani
- Department of Molecular and Human Genetics, Baylor College of Medicine and Texas Children's Hospital, Houston, TX, USA
| | - Svenja Scharre
- Center for Pediatric and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Joris Probst
- Center for Pediatric and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Magdalena E Walter
- Center for Pediatric and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Georg F Hoffmann
- Center for Pediatric and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Sven F Garbade
- Center for Pediatric and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Matthias Zielonka
- Center for Pediatric and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany; Heidelberg Research Center for Molecular Medicine (HRCMM), Heidelberg, Germany.
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Probst J, Kölker S, Okun JG, Kumar A, Gursky E, Posset R, Hoffmann GF, Peravali R, Zielonka M. Chronic hyperammonemia causes a hypoglutamatergic and hyperGABAergic metabolic state associated with neurobehavioral abnormalities in zebrafish larvae. Exp Neurol 2020; 331:113330. [PMID: 32339612 DOI: 10.1016/j.expneurol.2020.113330] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/29/2020] [Accepted: 04/23/2020] [Indexed: 12/13/2022]
Abstract
Chronic hyperammonemia is a common condition affecting individuals with inherited urea cycle disorders resulting in progressive cognitive impairment and behavioral abnormalities. Altered neurotransmission has been proposed as major source of neuronal dysfunction during chronic hyperammonemia, but the molecular pathomechanism has remained incompletely understood. Here we show that chronic exposure to ammonium acetate induces locomotor dysfunction and abnormal feeding behavior in zebrafish larvae, indicative for an impairment of higher brain functions. Biochemically, chronically elevated ammonium concentrations cause enhanced activity of glutamate decarboxylase isoforms GAD1 and GAD2 with increased formation of GABA and concomitant depletion of glutamate, ultimately leading to a dysfunctional hypoglutamatergic and hyperGABAergic metabolic state. Moreover, elevated GABA concentrations are accompanied by increased expression of GABAA receptor subunits alpha-1, gamma-2 and delta, supporting the notion of an increased GABA tone in chronic hyperammonemia. Propionate oxidation as major anaplerotic reaction sufficiently compensates for the transamination-dependent withdrawal of 2-oxoglutarate, thereby preventing bioenergetic dysfunction under chronic hyperammonemic conditions. Thus, our study extends the hypothesis of alterations in the glutamatergic and GABAergic system being an important pathophysiological factor causing neurobehavioral impairment in chronic hyperammonemia. Given that zebrafish larvae have already been successfully used for high-throughput identification of novel compounds to treat inherited neurological diseases, the reported zebrafish model should be considered an important tool for systematic drug screening targeting altered glutamatergic and GABAergic metabolism under chronic hyperammonemic conditions in the future.
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Affiliation(s)
- Joris Probst
- Center for Child and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Stefan Kölker
- Center for Child and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Jürgen G Okun
- Center for Child and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Amrish Kumar
- Institute of Toxicology and Genetics (ITG), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Eduard Gursky
- Institute of Toxicology and Genetics (ITG), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Roland Posset
- Center for Child and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Georg F Hoffmann
- Center for Child and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Ravindra Peravali
- Institute of Toxicology and Genetics (ITG), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Matthias Zielonka
- Center for Child and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany; Heidelberg Research Center for Molecular Medicine (HRCMM), Heidelberg, Germany.
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10
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Guazzelli PA, Cittolin-Santos GF, Meira-Martins LA, Grings M, Nonose Y, Lazzarotto GS, Nogara D, da Silva JS, Fontella FU, Wajner M, Leipnitz G, Souza DO, de Assis AM. Acute Liver Failure Induces Glial Reactivity, Oxidative Stress and Impairs Brain Energy Metabolism in Rats. Front Mol Neurosci 2020; 12:327. [PMID: 31998076 PMCID: PMC6968792 DOI: 10.3389/fnmol.2019.00327] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 12/18/2019] [Indexed: 01/02/2023] Open
Abstract
Acute liver failure (ALF) implies a severe and rapid liver dysfunction that leads to impaired liver metabolism and hepatic encephalopathy (HE). Recent studies have suggested that several brain alterations such as astrocytic dysfunction and energy metabolism impairment may synergistically interact, playing a role in the development of HE. The purpose of the present study is to investigate early alterations in redox status, energy metabolism and astrocytic reactivity of rats submitted to ALF. Adult male Wistar rats were submitted either to subtotal hepatectomy (92% of liver mass) or sham operation to induce ALF. Twenty-four hours after the surgery, animals with ALF presented higher plasmatic levels of ammonia, lactate, ALT and AST and lower levels of glucose than the animals in the sham group. Animals with ALF presented several astrocytic morphological alterations indicating astrocytic reactivity. The ALF group also presented higher mitochondrial oxygen consumption, higher enzymatic activity and higher ATP levels in the brain (frontoparietal cortex). Moreover, ALF induced an increase in glutamate oxidation concomitant with a decrease in glucose and lactate oxidation. The increase in brain energy metabolism caused by astrocytic reactivity resulted in augmented levels of reactive oxygen species (ROS) and Poly [ADP-ribose] polymerase 1 (PARP1) and a decreased activity of the enzymes superoxide dismutase and glutathione peroxidase (GSH-Px). These findings suggest that in the early stages of ALF the brain presents a hypermetabolic state, oxidative stress and astrocytic reactivity, which could be in part sustained by an increase in mitochondrial oxidation of glutamate.
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Affiliation(s)
- Pedro Arend Guazzelli
- Post-graduate Program in Biological Sciences: Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil.,Department of Biochemistry, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil
| | - Giordano Fabricio Cittolin-Santos
- Post-graduate Program in Biological Sciences: Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil.,Department of Biochemistry, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil
| | - Leo Anderson Meira-Martins
- Post-graduate Program in Biological Sciences: Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil
| | - Mateus Grings
- Post-graduate Program in Biological Sciences: Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil
| | - Yasmine Nonose
- Post-graduate Program in Biological Sciences: Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil
| | - Gabriel S Lazzarotto
- Post-graduate Program in Biological Sciences: Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil
| | - Daniela Nogara
- Department of Biochemistry, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil
| | - Jussemara S da Silva
- Post-graduate Program in Biological Sciences: Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil
| | - Fernanda U Fontella
- Post-graduate Program in Biological Sciences: Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil
| | - Moacir Wajner
- Post-graduate Program in Biological Sciences: Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil.,Department of Biochemistry, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil
| | - Guilhian Leipnitz
- Post-graduate Program in Biological Sciences: Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil
| | - Diogo O Souza
- Post-graduate Program in Biological Sciences: Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil.,Department of Biochemistry, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil
| | - Adriano Martimbianco de Assis
- Post-graduate Program in Biological Sciences: Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil.,Post-graduate Program in Health and Behavior, Health Sciences Centre, Universidade Católica de Pelotas-UCPel, Pelotas, Brazil
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11
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Wang M, Cui J, Liu Y, Zhou Y, Wang H, Wang Y, Zhu Y, Nguchu BA, Qiu B, Wang X, Yu Y. Structural and functional abnormalities of vision-related brain regions in cirrhotic patients: a MRI study. Neuroradiology 2019; 61:695-702. [PMID: 30949745 PMCID: PMC6511351 DOI: 10.1007/s00234-019-02199-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 03/12/2019] [Indexed: 12/20/2022]
Abstract
Purpose Previous studies have focused on global cerebral alterations observed in cirrhosis. However, little was known about the specific abnormalities of vision-related brain regions in cirrhotic patients. In this study, we sought to explore neurological alterations of vision-related regions by measuring brain resting-state network connectivity, based on the structural investigation in cirrhotic patients without clinical sign of hepatic encephalopathy (HE). Methods Structural and functional magnetic resonance image (MRI) data were collected from 20 hepatitis B virus (HBV)-related cirrhotic patients without clinical sign of HE and from 20 healthy controls (HC). Voxel-based morphometric (VBM) analysis and brain functional network analysis were performed to detect abnormalities in cerebral structure and function. Results Cirrhotic patients showed regions with the most significant gray matter reduction primarily in vision-related brain regions, including the bilateral lingual gyri, left putamen, right fusiform gyrus, and right calcarine gyrus, and other significant gray matter reductions were distributed in bilateral hippocampus. Based on structural investigation focused on vision-related regions, brain functional network analysis revealed decreased functional connectivity between brain functional networks within vision-related regions (primary visual network (PVN), higher visual network (HVN), visuospatial network (VSN)) in the patient group compared with HC group. Conclusion These results indicate that structural and functional impairment were evident in the vision-related brain regions in cirrhotic patients without clinical sign of hepatic encephalopathy. The physiopathology and clinical relevance of these changes could not be ascertained from the present study, which provided a basis for further evolution of the disease.
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Affiliation(s)
- Mingquan Wang
- Department of Radiology, The First Affiliated Hospital of AnHui Medical University, Hefei, 230022, Anhui, China
| | - Jin Cui
- Centers for Biomedical Engineering, University of Science and Technology of China, Hefei, Anhui, China
| | - Yanpeng Liu
- Centers for Biomedical Engineering, University of Science and Technology of China, Hefei, Anhui, China
| | - Yawen Zhou
- Centers for Biomedical Engineering, University of Science and Technology of China, Hefei, Anhui, China
| | - Huijuan Wang
- Centers for Biomedical Engineering, University of Science and Technology of China, Hefei, Anhui, China
| | - Yanming Wang
- Centers for Biomedical Engineering, University of Science and Technology of China, Hefei, Anhui, China
| | - Yuying Zhu
- Centers for Biomedical Engineering, University of Science and Technology of China, Hefei, Anhui, China
| | | | - Bensheng Qiu
- Centers for Biomedical Engineering, University of Science and Technology of China, Hefei, Anhui, China
| | - Xiaoxiao Wang
- Centers for Biomedical Engineering, University of Science and Technology of China, Hefei, Anhui, China
| | - Yongqiang Yu
- Department of Radiology, The First Affiliated Hospital of AnHui Medical University, Hefei, 230022, Anhui, China.
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12
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Heidari R. Brain mitochondria as potential therapeutic targets for managing hepatic encephalopathy. Life Sci 2019; 218:65-80. [DOI: 10.1016/j.lfs.2018.12.030] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 12/08/2018] [Accepted: 12/16/2018] [Indexed: 02/07/2023]
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Silencing of Transcription Factor Sp1 Promotes SN1 Transporter Regulation by Ammonia in Mouse Cortical Astrocytes. Int J Mol Sci 2019; 20:ijms20020234. [PMID: 30634395 PMCID: PMC6359076 DOI: 10.3390/ijms20020234] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 12/27/2018] [Accepted: 12/27/2018] [Indexed: 12/15/2022] Open
Abstract
The involvement of the astrocytic SN1 (SNAT3) transporter in ammonia-induced l-glutamine retention was recently documented in mouse-cultured astrocytes. Here we investigated the involvement of specificity protein 1 (Sp1) transcription factor in SN1 regulation in ammonium chloride (“ammonia”)-treated astrocytes. Sp1 expression and its cellular localization were determined using real-time qPCR, Western blot, and confocal microscopy. Sp1 binding to Snat3 promoter was analyzed by chromatin immunoprecipitation. The role of Sp1 in SN1 expression and SN1-mediated [3H]glutamine uptake in ammonia-treated astrocytes was verified using siRNA and mithramycin A. The involvement of protein kinase C (PKC) isoforms in Sp1 level/phosphorylation status was verified using siRNA technology. Sp1 translocation to the nuclei and its enhanced binding to the Snat3 promoter, along with Sp1 dependence of system N-mediated [3H]glutamine uptake, were observed in astrocytes upon ammonia exposure. Ammonia decreased the level of phosphorylated Sp1, and the effect was reinforced by long-term incubation with PKC modulator, phorbol 12-myristate 13-acetate, which is a treatment likely to dephosphorylate Sp1. Furthermore, silencing of the PKCδ isoform appears to enhance the ammonia effect on the Sp1 level. Collectively, the results demonstrate the regulatory role of Sp1 in regulation of SN1 expression and activity in ammonia-treated astrocytes and implicate altered Sp1 phosphorylation status in this capacity.
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14
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Dąbrowska K, Albrecht J, Zielińska M. Protein kinase C-mediated impairment of glutamine outward transport and SN1 transporter distribution by ammonia in mouse cortical astrocytes. Neurochem Int 2018; 118:225-232. [DOI: 10.1016/j.neuint.2018.07.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 06/19/2018] [Accepted: 07/03/2018] [Indexed: 01/07/2023]
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15
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Jayakumar AR, Norenberg MD. Hyperammonemia in Hepatic Encephalopathy. J Clin Exp Hepatol 2018; 8:272-280. [PMID: 30302044 PMCID: PMC6175739 DOI: 10.1016/j.jceh.2018.06.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 06/10/2018] [Indexed: 12/12/2022] Open
Abstract
The precise mechanism underlying the neurotoxicity of Hepatic Encephalopathy (HE) is remains unclear. The dominant view has been that gut-derived nitrogenous toxins are not extracted by the diseased liver and thereby enter the brain. Among the various toxins proposed, the case for ammonia is most compelling. Events that lead to increased levels of blood or brain ammonia have been shown to worsen HE, whereas reducing blood ammonia levels alleviates HE. Clinical, pathological, and biochemical changes observed in HE can be reproduced by increasing blood or brain ammonia levels in experimental animals, while exposure of cultured astrocytes to ammonium salts reproduces the morphological and biochemical findings observed in HE. However, factors other than ammonia have recently been proposed to be involved in the development of HE, including cytokines and other blood and brain immune factors. Moreover, recent studies have questioned the critical role of ammonia in the pathogenesis of HE since blood ammonia levels do not always correlate with the level/severity of encephalopathy. This review summarizes the vital role of ammonia in the pathogenesis of HE in humans, as well as in experimental models of acute and chronic liver failure. It further emphasizes recent advances in the molecular mechanisms involved in the progression of neurological complications that occur in acute and chronic liver failure.
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Key Words
- AHE, Acute Hepatic Encephalopathy
- ALF, Acute Liver Failure
- CHE, Chronic Hepatic Encephalopathy
- CNS, Central Nervous System
- CSF, Cerebrospinal Fluid
- ECs, Endothelial Cells
- HE, Hepatic Encephalopathy
- IL, Interleukin
- LPS, Lipopolysaccharide
- MAPKs, Mitogen-Activated Protein Kinases
- NCX, Sodium-Calcium Exchanger
- NF-κB, Nuclear Factor-kappaB
- NHE, Sodium/Hydrogen Exchanger-1 or SLC9A1 (SoLute Carrier Family 9A1)
- SUR1, The Sulfonylurea Receptor 1
- TDP-43 and tau proteinopathies
- TDP-43, TAR DNA-Binding Protein, 43 kDa
- TLR, Toll-like Receptor
- TNF-α, Tumor Necrosis Factor-Alpha
- TSP-1, Thrombospondin-1
- ammonia
- hepatic encephalopathy
- inflammation
- matricellular proteins
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Affiliation(s)
- A R Jayakumar
- General Medical Research, Neuropathology Section, R&D Service, Veterans Affairs Medical Center, Miami, FL 33125, United States
- South Florida VA Foundation for Research and Education Inc., Veterans Affairs Medical Center, Miami, FL 33125, United States
| | - Michael D Norenberg
- Department of Pathology, University of Miami School of Medicine, Miami, FL 33125, United States
- Department of Biochemistry & Molecular Biology, University of Miami School of Medicine, Miami, FL 33125, United States
- Department of Neurology and Neurological Surgery, University of Miami School of Medicine, Miami, FL 33125, United States
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Wilson CS, Mongin AA. Cell Volume Control in Healthy Brain and Neuropathologies. CURRENT TOPICS IN MEMBRANES 2018; 81:385-455. [PMID: 30243438 DOI: 10.1016/bs.ctm.2018.07.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Regulation of cellular volume is a critical homeostatic process that is intimately linked to ionic and osmotic balance in the brain tissue. Because the brain is encased in the rigid skull and has a very complex cellular architecture, even minute changes in the volume of extracellular and intracellular compartments have a very strong impact on tissue excitability and function. The failure of cell volume control is a major feature of several neuropathologies, such as hyponatremia, stroke, epilepsy, hyperammonemia, and others. There is strong evidence that such dysregulation, especially uncontrolled cell swelling, plays a major role in adverse pathological outcomes. To protect themselves, brain cells utilize a variety of mechanisms to maintain their optimal volume, primarily by releasing or taking in ions and small organic molecules through diverse volume-sensitive ion channels and transporters. In principle, the mechanisms of cell volume regulation are not unique to the brain and share many commonalities with other tissues. However, because ions and some organic osmolytes (e.g., major amino acid neurotransmitters) have a strong impact on neuronal excitability, cell volume regulation in the brain is a surprisingly treacherous process, which may cause more harm than good. This topical review covers the established and emerging information in this rapidly developing area of physiology.
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Affiliation(s)
- Corinne S Wilson
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, United States
| | - Alexander A Mongin
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, United States; Department of Biophysics and Functional Diagnostics, Siberian State Medical University, Tomsk, Russian Federation
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Karvellas CJ, Speiser JL, Tremblay M, Lee WM, Rose CF. The association between FABP7 serum levels with survival and neurological complications in acetaminophen-induced acute liver failure: a nested case-control study. Ann Intensive Care 2017; 7:99. [PMID: 28983815 PMCID: PMC5629189 DOI: 10.1186/s13613-017-0323-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 09/19/2017] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Acetaminophen (APAP)-induced acute liver failure (ALF) is associated with significant mortality due to intracranial hypertension (ICH), a result of cerebral edema (CE) and astrocyte swelling. Brain-type fatty acid-binding protein (FABP7) is a small (15 kDa) cytoplasmic protein abundantly expressed in astrocytes. The aim of this study was to determine whether serum FABP7 levels early (day 1) or late (days 3-5) level were associated with 21-day mortality and/or the presence of ICH/CE in APAP-ALF patients. METHODS Serum samples from 198 APAP-ALF patients (nested case-control study with 99 survivors and 99 non-survivors) were analyzed by ELISA methods and assessed with clinical data from the US Acute Liver Failure Study Group (ALFSG) Registry (1998-2014). RESULTS APAP-ALF survivors had significantly lower serum FABP7 levels on admission (147.9 vs. 316.5 ng/ml, p = 0.0002) and late (87.3 vs. 286.2 ng/ml, p < 0.0001) compared with non-survivors. However, a significant association between 21-day mortality and increased serum FABP7 early [log FABP7 odds ratio (OR) 1.16, p = 0.32] and late (log FABP7 ~ OR 1.34, p = 0.21) was not detected after adjusting for significant covariates (MELD, vasopressor use). Areas under the receiver-operating curve for early and late multivariable models were 0.760 and 0.892, respectively. In a second analysis, patients were grouped based on the presence (n = 46) or absence (n = 104) of ICH/CE. A significant difference in FABP7 levels between patients with or without ICH/CE at early (259.7 vs. 228.2 ng/ml, p = 0.61) and late (223.8 vs. 192.0 ng/ml, p = 0.19) time points was not identified. CONCLUSION Serum FABP7 levels were significantly elevated at early and late time points in APAP-ALF non-survivors compared to survivors. However, significant differences in FABP7 levels by 21-day mortality were not ascertained after adjusting for significant covariates (reflecting severity of illness). Our study suggests that FABP7 may not discriminate between patients with or without intracranial complications.
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Affiliation(s)
- Constantine J Karvellas
- Division of Gastroenterology (Liver Unit), Department of Critical Care Medicine, University of Alberta, 1-40 Zeidler Ledcor Building, Edmonton, AB, T6G-2X8, Canada.
| | - Jaime L Speiser
- Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC, USA
| | - Mélanie Tremblay
- Hepato-Neuro Laboratory, CRCHUM, Université de Montréal, Montreal, Canada
| | - William M Lee
- Division of Digestive and Liver Diseases, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Christopher F Rose
- Hepato-Neuro Laboratory, CRCHUM, Université de Montréal, Montreal, Canada
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Abstract
Hepatic encephalopathy (HE) is a reversible syndrome of impaired brain function occurring in patients with advanced liver diseases. The precise pathophysiology of HE is still under discussion; the leading hypothesis focus on the role of neurotoxins, impaired neurotransmission due to metabolic changes in liver failure, changes in brain energy metabolism, systemic inflammatory response and alterations of the blood brain barrier. HE produces a wide spectrum of nonspecific neurological and psychiatric manifestations. Minimal HE is diagnosed by abnormal psychometric tests. Clinically overt HE includes personality changes, alterations in consciousness progressive disorientation in time and space, somnolence, stupor and, finally, coma. Except for clinical studies, no specific tests are required for diagnosis. HE is classified according to the underlying disease, the severity of manifestations, its time course and the existence of precipitating factors. Treatment of overt HE includes supportive therapies, treatment of precipitating factors, lactulose and/or rifaximin. Routine treatment for minimal HE is only recommended for selected patients.
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Affiliation(s)
- Peter Ferenci
- Department of Internal Medicine III, Division of Gastroenterology and Hepatology, Medical University of Vienna, Vienna, Austria
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Brusilow WSA, Peters TJ. Therapeutic effects of methionine sulfoximine in multiple diseases include and extend beyond inhibition of glutamine synthetase. Expert Opin Ther Targets 2017; 21:461-469. [PMID: 28292200 DOI: 10.1080/14728222.2017.1303484] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
INTRODUCTION Methionine sulfoximine (MSO), a well-characterized inhibitor of glutamine synthetase, displays significant therapeutic benefits in animal models for several human diseases. This amino acid might therefore be a viable candidate for drug development to treat diseases for which there are few effective therapies. Areas covered: We describe the effects of MSO on brain swelling occurring in overt hepatic encephalopathy resulting from liver failure, the effects of MSO on excitotoxic damage involved in amyotrophic lateral sclerosis (ALS) or resulting from stroke, and the effects of MSO on a model for an inflammatory immune response involved in a range of diseases. We conclude that these results imply the existence of another therapeutic target for MSO in addition to glutamine synthetase. Expert opinion: We summarize the various diseases for which MSO treatment might be a candidate for drug development. We discuss why MSO has limited enthusiasm in the scientific and medical communities for use in humans, with a rebuttal to those negative opinions. And we conclude that MSO should be considered a candidate drug to treat brain swelling involved in overt hepatic encephalopathy and diseases involving an inflammatory immune response.
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Affiliation(s)
- William S A Brusilow
- a Department of Biochemistry and Molecular Biology , Wayne State University School of Medicine , Detroit , MI , USA
| | - Tyler J Peters
- a Department of Biochemistry and Molecular Biology , Wayne State University School of Medicine , Detroit , MI , USA
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Anesthesia for Liver Transplantation. Anesthesiology 2017. [DOI: 10.1007/978-3-319-50141-3_28] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Hyperammonemia: What Urea-lly Need to Know: Case Report of Severe Noncirrhotic Hyperammonemic Encephalopathy and Review of the Literature. Case Rep Med 2016; 2016:8512721. [PMID: 27738433 PMCID: PMC5050374 DOI: 10.1155/2016/8512721] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 08/28/2016] [Indexed: 12/12/2022] Open
Abstract
Purpose. A 66-year-old man who presented with coma was found to have isolated severe hyperammonemia and diagnosed with a late-onset urea-cycle disorder. He was treated successfully and had full recovery. Methods. We report a novel case of noncirrhotic hyperammonemia and review the literature on this topic. Selected literature for review included English-language articles concerning hyperammonemia using the search terms “hyperammonemic encephalopathy”, “non-cirrhotic encephalopathy”, “hepatic encephalopathy”, “urea-cycle disorders”, “ornithine transcarbamylase (OTC) deficiency”, and “fulminant hepatic failure”. Results. A unique case of isolated hyperammonemia diagnosed as late-onset OTC deficiency is presented. Existing evidence about hyperammonemia is organized to address pathophysiology, clinical presentation, diagnosis, and treatment. The case report is discussed in context of the reviewed literature. Conclusion. Late-onset OTC deficiency presenting with severe hyperammonemic encephalopathy and extensive imaging correlate can be fully reversible if recognized promptly and treated aggressively.
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Lizaola B, Bonder A, Tapper EB, Mendez-Bocanegra A, Cardenas A. The Changing Role of Sodium Management in Cirrhosis. ACTA ACUST UNITED AC 2016; 14:274-84. [DOI: 10.1007/s11938-016-0094-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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23
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Mongin AA. Volume-regulated anion channel--a frenemy within the brain. Pflugers Arch 2015; 468:421-41. [PMID: 26620797 DOI: 10.1007/s00424-015-1765-6] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 11/16/2015] [Accepted: 11/20/2015] [Indexed: 10/22/2022]
Abstract
The volume-regulated anion channel (VRAC) is a ubiquitously expressed yet highly enigmatic member of the superfamily of chloride/anion channels. It is activated by cellular swelling and mediates regulatory cell volume decrease in a majority of vertebrate cells, including those in the central nervous system (CNS). In the brain, besides its crucial role in cellular volume regulation, VRAC is thought to play a part in cell proliferation, apoptosis, migration, and release of physiologically active molecules. Although these roles are not exclusive to the CNS, the relative significance of VRAC in the brain is amplified by several unique aspects of its physiology. One important example is the contribution of VRAC to the release of the excitatory amino acid neurotransmitters glutamate and aspartate. This latter process is thought to have impact on both normal brain functioning (such as astrocyte-neuron signaling) and neuropathology (via promoting the excitotoxic death of neuronal cells in stroke and traumatic brain injury). In spite of much work in the field, the molecular nature of VRAC remained unknown until less than 2 years ago. Two pioneer publications identified VRAC as the heterohexamer formed by the leucine-rich repeat-containing 8 (LRRC8) proteins. These findings galvanized the field and are likely to result in dramatic revisions to our understanding of the place and role of VRAC in the brain, as well as other organs and tissues. The present review briefly recapitulates critical findings in the CNS and focuses on anticipated impact on the LRRC8 discovery on further progress in neuroscience research.
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Affiliation(s)
- Alexander A Mongin
- Center for Neuropharmacology and Neuroscience, Albany Medical College, 47 New Scotland Ave., Albany, NY, 12208, USA.
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Trogadas G, Mastoraki A, Nastos C, Kondi-Pafiti A, Kostopanagiotou G, Smyrniotis V, Arkadopoulos N. Comparative Effects of Ischemic Preconditioning and Iron Chelation in Hepatectomy. J INVEST SURG 2015; 28:261-7. [PMID: 26270074 DOI: 10.3109/08941939.2015.1024803] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
PURPOSE/AIM Major hepatectomies can result in severe ischemia/reperfusion (I/R) injury of the liver. The aim of this survey is to comparatively evaluate the effects of a surgical and a pharmacological hepatoprotective modality on the liver remnant in a porcine model of hepatectomy. MATERIAL AND METHODS Twenty-one Landrace pigs were randomly divided into three groups: a control group (CON) (n = 7), an Ischemic Preconditioning (PRE) group (n = 7) and a Desferoxamine (DFX) treated one (n = 7). Animals were subjected to 120 min of liver ischemia with subsequent 75% hepatectomy followed by 24-hr reperfusion. In all animals, continuous intracranial pressure (ICP) monitoring was employed. Blood samples were collected at t0, t6, t12, and t24 hrs after reperfusion. Liver remnant specimens were excised for histological examination. RESULTS In the PRE group, ICP was statistically lower at t6 time point compared to CON group and in comparison with t0. In addition, ICP was significantly lower at all-time points after reperfusion in the DFX group. Finally, with regard to DFX and PRE group correlation, ICP was significantly lower at t0, t12, and t24 time points after reperfusion in the DFX group. In the PRE group, NH3 levels were significantly lower at t12 after reperfusion compared to CON and DFX groups. Histological evaluation elucidated significantly less hepatocellular necrosis, apoptosis, and degeneration in the PRE and DFX groups correlated to CON group. CONCLUSIONS Both hepatoprotective modalities including PRE and DFX administration are associated with lower ICP levels and correlated with attenuated liver remnant injury.
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Affiliation(s)
- Georgios Trogadas
- a 4th Department of Surgery, Athens University, Medical School, ATTIKON University Hospital , Chaidari , Athens , Greece
| | - Aikaterini Mastoraki
- a 4th Department of Surgery, Athens University, Medical School, ATTIKON University Hospital , Chaidari , Athens , Greece
| | - Constantinos Nastos
- a 4th Department of Surgery, Athens University, Medical School, ATTIKON University Hospital , Chaidari , Athens , Greece
| | - Agathi Kondi-Pafiti
- b Department of Pathology, Aretaieion Hospital, University of Athens Medical School , Athens , Greece
| | - Georgia Kostopanagiotou
- c 2nd Department of Anesthesiology, Athens University, Medical School, ATTIKON University Hospital , Chaidari , Athens , Greece
| | - Vassilios Smyrniotis
- a 4th Department of Surgery, Athens University, Medical School, ATTIKON University Hospital , Chaidari , Athens , Greece
| | - Nikolaos Arkadopoulos
- a 4th Department of Surgery, Athens University, Medical School, ATTIKON University Hospital , Chaidari , Athens , Greece
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Ding S, Yang J, Liu L, Ye Y, Wang X, Hu J, Chen B, Zhuge Q. Elevated dopamine induces minimal hepatic encephalopathy by activation of astrocytic NADPH oxidase and astrocytic protein tyrosine nitration. Int J Biochem Cell Biol 2014; 55:252-63. [DOI: 10.1016/j.biocel.2014.09.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 08/14/2014] [Accepted: 09/01/2014] [Indexed: 12/12/2022]
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Hepatic Encephalopathy: From the Pathogenesis to the New Treatments. ISRN HEPATOLOGY 2014; 2014:236268. [PMID: 27335836 PMCID: PMC4890879 DOI: 10.1155/2014/236268] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 01/28/2014] [Indexed: 02/07/2023]
Abstract
Hepatic encephalopathy is a frequent and serious complication of liver cirrhosis; the pathophysiology of this complication is not fully understood although great efforts have been made during the last years. There are few prospective studies on the epidemiology of this complication; however, it is known that it confers with high short-term mortality. Hepatic encephalopathy has been classified into different groups depending on the degree of hepatic dysfunction, the presence of portal-systemic shunts, and the number of episodes. Due to the large clinical spectra of overt EH and the complexity of cirrhotic patients, it is very difficult to perform quality clinical trials for assessing the efficacy of the treatments proposed. The physiopathology, clinical manifestation, and the treatment of HE is a challenge because of the multiple factors that converge and coexist in an episode of overt HE.
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Abstract
Alcohol abuse and dependence are serious public health problems worldwide, resulting in significant morbidity, mortality, and legal implications. Therefore, sudden unexpected, suspicious, or violent death in alcohol consuming persons are frequently seen in the forensic setting. Alcohol-induced brain damage is predominantly caused by nutritional deficiencies and repeated withdrawal syndrome. Brain lesions associated with heavy alcohol consumption include brain atrophy, hepatic encephalopathy, and central pontine myelinolysis. In addition, the dementing conditions Wernicke-Korsakoff syndrome, acquired hepatocerebral degeneration, Marchiafava-Bignami disease, and pellagrous encephalopathy are closely associated with chronic alcohol consumption. In neuroradiological and autopsy studies, cerebral and cerebellar atrophy has been demonstrated in alcoholics. There is a regional selectivity, with the frontal lobes being particularly affected. Moreover, a disproportionate loss of cerebral white matter relative to cerebral cortex suggests that a major neurotoxic effect of chronic alcohol consumption predominantly affects the white matter.
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Affiliation(s)
- Andreas Büttner
- Forensic Pathology and the Institute of Legal Medicine at the Medical University of Rostock, Germany
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Chastre A, Bélanger M, Nguyen BN, Butterworth RF. Lipopolysaccharide precipitates hepatic encephalopathy and increases blood-brain barrier permeability in mice with acute liver failure. Liver Int 2014; 34:353-61. [PMID: 23910048 DOI: 10.1111/liv.12252] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 05/16/2013] [Accepted: 05/31/2013] [Indexed: 12/25/2022]
Abstract
BACKGROUND & AIMS Acute liver failure (ALF) is frequently complicated by infection leading to precipitation of central nervous system complications such as hepatic encephalopathy (HE) and increased mortality. There is evidence to suggest that when infection occurs in ALF patients, the resulting pro-inflammatory mechanisms may be amplified that could, in turn, have a major impact on blood-brain barrier (BBB) function. The aim of this study was to investigate the role of endotoxemia on the progression of encephalopathy in relation to BBB permeability during ALF. METHODS Adult male C57-BL6 mice with ALF resulting from azoxymethane-induced toxic liver injury were administered trace amounts of the endotoxin component lipopolysaccharide (LPS). Effects on the magnitude of the systemic inflammatory response, liver pathology and BBB integrity were measured as a function of progression of HE, defined as time to loss of corneal reflex (coma). RESULTS Lipopolysaccharide caused additional two- to seven-fold (P < 0.001) increases in circulating pro-inflammatory cytokines (TNF-α, IL-1β, IL-6), worsening liver pathology and associated increases of circulating transaminases as well as increased hyperammonaemia consistent with a further loss of viable hepatocytes. LPS treatment of ALF mice led to a rapid precipitation of hepatic coma and the BBB became permeable to the 25-kDa protein immunoglobulin G (IgG). This extravasation of IgG was accompanied by ignificant up-regulation of matrix metalloproteinase-9 (MMP-9), an endopeptidase known to modulate opening of the BBB in a wide range of neurological disorders. CONCLUSIONS These findings represent the first direct evidence of inflammation-related BBB permeability changes in ALF.
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Affiliation(s)
- Anne Chastre
- Neuroscience Research Unit, Saint-Luc Hospital, CRCHUM, Montreal, QC, Canada
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Joshi D, O'Grady J, Patel A, Shawcross D, Connor S, Deasy N, Willars C, Bernal W, Wendon J, Auzinger G. Cerebral oedema is rare in acute-on-chronic liver failure patients presenting with high-grade hepatic encephalopathy. Liver Int 2014; 34:362-6. [PMID: 23844567 DOI: 10.1111/liv.12257] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 06/05/2013] [Accepted: 06/12/2013] [Indexed: 01/05/2023]
Abstract
BACKGROUND & AIMS Acute-on-chronic liver failure (ACLF) has a rapidly progressive disease course associated with significant mortality. The prevalence of clinically significant cerebral oedema in ACLF is unknown. METHODS We aimed to describe the prevalence of cerebral oedema in a cohort of ACLF adult (>18 years). We identified patients admitted to a single, specialist intensive care unit between January 2005 and January 2011 with high-grade hepatic encephalopathy (≥3) and a clinical picture of either ACLF or chronic liver disease (CLD). Patients who had undergone cranial CT imaging were identified and their imaging reviewed. The ACLF and CLD groups were compared. RESULTS One thousand and eight patients with CLD were admitted. One hundred and seventy-three patients (110 male) underwent neuroimaging. Eighty-one (48 male) fulfilled criteria for ACLF. Variceal bleeding (30%) and sepsis (31%) were the most frequent precipitants of ACLF. Of those with neuroimaging from the total cohort, 30% of CT scans were normal, 30% demonstrated increased cerebral atrophy for age, 17% small vessel disease and 16% intracranial haemorrhage (ICH). Cerebral oedema was seen in three patients with ACLF only. An increased prevalence of ICH was observed in the ACLF group (23% vs. 9%, P = 0.008). CONCLUSION The prevalence of clinically relevant cerebral oedema was low (4%) but fatal. Death was attributable to tonsillar herniation. An increased prevalence of ICH was seen in ACLF patients and remains an important differential.
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Affiliation(s)
- Deepak Joshi
- Institute of Liver Studies, King's College Hospital, London, UK
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Abstract
Fulminant hepatic failure presents with a hepatic encephalopathy and may progress to coma and often brain death from cerebral edema. This natural progression in severe cases contributes to early mortality, but outcome can be good if liver transplantation is appropriately timed and increased intracranial pressure (ICP) is managed. Neurologists and neurosurgeons have become more involved in these very challenging patients and are often asked to rapidly identify patients who are at risk of cerebral edema, to carefully select the patient population who will benefit from invasive ICP monitoring, to judge the correct time to start monitoring, to participate in treatment of cerebral edema, and to manage complications such as intracranial hemorrhage or seizures. This chapter summarizes the current multidisciplinary approach to fulminant hepatic failure and how to best bridge patients to emergency liver transplantation.
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Scott TR, Kronsten VT, Hughes RD, Shawcross DL. Pathophysiology of cerebral oedema in acute liver failure. World J Gastroenterol 2013; 19:9240-9255. [PMID: 24409052 PMCID: PMC3882398 DOI: 10.3748/wjg.v19.i48.9240] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 10/28/2013] [Accepted: 11/19/2013] [Indexed: 02/06/2023] Open
Abstract
Cerebral oedema is a devastating consequence of acute liver failure (ALF) and may be associated with the development of intracranial hypertension and death. In ALF, some patients may develop cerebral oedema and increased intracranial pressure but progression to life-threatening intracranial hypertension is less frequent than previously described, complicating less than one third of cases who have proceeded to coma since the advent of improved clinical care. The rapid onset of encephalopathy may be dramatic with the development of asterixis, delirium, seizures and coma. Cytotoxic and vasogenic oedema mechanisms have been implicated with a preponderance of experimental data favouring a cytotoxic mechanism. Astrocyte swelling is the most consistent neuropathological finding in humans with ALF and ammonia plays a definitive role in the development of cytotoxic brain oedema. The mechanism(s) by which ammonia induces astrocyte swelling remains unclear but glutamine accumulation within astrocytes has led to the osmolyte hypothesis. Current evidence also supports an alternate ‘Trojan horse’ hypothesis, with glutamine as a carrier of ammonia into mitochondria, where its accumulation results in oxidative stress, energy failure and ultimately astrocyte swelling. Although a complete breakdown of the blood-brain barrier is not evident in human ALF, increased permeation to water and other small molecules such as ammonia has been demonstrated resulting from subtle alterations in the protein composition of paracellular tight junctions. At present, there is no fully efficacious therapy for cerebral oedema other than liver transplantation and this reflects our incomplete knowledge of the precise mechanisms underlying this process which remain largely unknown.
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Bodega G, Suárez I, López-Fernández LA, García MI, Köber M, Penedo M, Luna M, Juárez S, Ciordia S, Oria M, Córdoba J, Fernández B. Ammonia induces aquaporin-4 rearrangement in the plasma membrane of cultured astrocytes. Neurochem Int 2012; 61:1314-24. [PMID: 23022607 DOI: 10.1016/j.neuint.2012.09.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 09/06/2012] [Accepted: 09/13/2012] [Indexed: 11/30/2022]
Abstract
Aquaporin-4 (AQP4) is a water channel protein mainly located in the astroglial plasma membrane, the precise function of which in the brain edema that accompanies hepatic encephalopathy (HE) is unclear. Since ammonia is the main pathogenic agent in HE, its effect on AQP4 expression and distribution in confluent primary astroglial cultures was examined via their exposure to ammonium chloride (1, 3 and 5 mM) for 5 and 10 days. Ammonia induced the general inhibition of AQP4 mRNA synthesis except in the 1 mM/5 day treatment. However, the AQP4 protein content measured was dependent on the method of analysis; an apparent increase was recorded in treated cells in in-cell Western assays, while an apparent reduction was seen with the classic Western blot method, perhaps due to differences in AQP4 aggregation. Ammonia might therefore induce the formation of insoluble AQP4 aggregates in the astroglial plasma membrane. The finding of AQP4 in the pellet of classic Western blot samples, plus data obtained via confocal microscopy, atomic force microscopy (using immunolabeled cells with gold nanoparticles) and scanning electron microscopy, all corroborate this hypothesis. The effect of ammonia on AQP4 seems not to be due to any osmotic effect; identical osmotic stress induced by glutamine and salt had no significant effect on the AQP4 content. AQP4 functional analysis (subjecting astrocytes to a hypo-osmotic medium and using flow cytometry to measure cell size) demonstrated a smaller water influx in ammonia-treated astrocytes suggesting that AQP4 aggregates are representative of an inactive status; however, more confirmatory studies are required to fully understand the functional status of AQP4 aggregates. The present results suggest that ammonia affects AQP4 expression and distribution, and that astrocytes change their expression of AQP4 mRNA as well as the aggregation status of the ensuing protein depending on the ammonia concentration and duration of exposure.
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Affiliation(s)
- Guillermo Bodega
- Departamento de Biología Celular y Genética, Facultad de Biología, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain.
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Mangia S, Giove F, Dinuzzo M. Metabolic pathways and activity-dependent modulation of glutamate concentration in the human brain. Neurochem Res 2012; 37:2554-61. [PMID: 22846967 DOI: 10.1007/s11064-012-0848-4] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Revised: 06/21/2012] [Accepted: 07/14/2012] [Indexed: 12/26/2022]
Abstract
Glutamate is one of the most versatile molecules present in the human brain, involved in protein synthesis, energy production, ammonia detoxification, and transport of reducing equivalents. Aside from these critical metabolic roles, glutamate plays a major part in brain function, being not only the most abundant excitatory neurotransmitter, but also the precursor for γ-aminobutyric acid, the predominant inhibitory neurotransmitter. Regulation of glutamate levels is pivotal for normal brain function, as abnormal extracellular concentration of glutamate can lead to impaired neurotransmission, neurodegeneration and even neuronal death. Understanding how the neuron-astrocyte functional and metabolic interactions modulate glutamate concentration during different activation status and under physiological and pathological conditions is a challenging task, and can only be tentatively estimated from current literature. In this paper, we focus on describing the various metabolic pathways which potentially affect glutamate concentration in the brain, and emphasize which ones are likely to produce the variations in glutamate concentration observed during enhanced neuronal activity in human studies.
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Affiliation(s)
- Silvia Mangia
- Department of Radiology, Center for Magnetic Resonance Research, University of Minnesota, 2021 6th St. S.E., Minneapolis, MN, USA.
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Mpabanzi L, Jalan R. Neurological complications of acute liver failure: pathophysiological basis of current management and emerging therapies. Neurochem Int 2011; 60:736-42. [PMID: 22100567 DOI: 10.1016/j.neuint.2011.10.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Revised: 10/17/2011] [Accepted: 10/26/2011] [Indexed: 12/11/2022]
Abstract
One of the major causes of mortality in patients with acute liver failure (ALF) is the development of hepatic encephalopathy (HE) which is associated with increased intracranial pressure (ICP). High ammonia levels, increased cerebral blood flow and increased inflammatory response have been identified as major contributors to the development of HE and the related brain swelling. The general principles of the management of patients with ALF are straightforward. They include identifying the insult causing hepatic injury, providing organ systems support to optimize the patient's physical condition, anticipation and prevention of development of complications. Increasing insights into the pathophysiological mechanisms of ALF are contributing to better therapies. For instance, the evident role of cerebral hyperemia in the pathogenesis of increased ICP has led to a re-evaluation of established therapies such as hyperventilation, N-acetylcysteine, thiopentone sodium and propofol. The role of systemic inflammatory response in the pathogenesis of increased ICP has also gained importance supporting the concept that antibiotics given prophylactically reduce the risk of developing sepsis during the course of illness. Moderate hypothermia has also been established as a therapy able to reduce ICP in patients with uncontrolled intracranial hypertension and to prevent increases in ICP during orthopic liver transplantation. Ornithine phenylacetate, a new drug in the treatment of liver failure, and liver replacement therapies are still being investigated both experimentally and clinically. Despite many advances in the understanding of the pathophysiological basis and the management of intracranial hypertension in ALF, more clinical trials should be conducted to determine the best therapeutic management for this difficult clinical event.
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Affiliation(s)
- Liliane Mpabanzi
- Department of Surgery, Maastricht University Medical Centre, and NUTRIM School of Nutrition, Toxicology and Metabolism, Maastricht University, PO Box 5800, Maastricht, The Netherlands
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Kim K, Lee SG, Kegelman TP, Su ZZ, Das SK, Dash R, Dasgupta S, Barral PM, Hedvat M, Diaz P, Reed JC, Stebbins JL, Pellecchia M, Sarkar D, Fisher PB. Role of excitatory amino acid transporter-2 (EAAT2) and glutamate in neurodegeneration: opportunities for developing novel therapeutics. J Cell Physiol 2011; 226:2484-93. [PMID: 21792905 DOI: 10.1002/jcp.22609] [Citation(s) in RCA: 285] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Glutamate is an essential excitatory neurotransmitter regulating brain functions. Excitatory amino acid transporter (EAAT)-2 is one of the major glutamate transporters expressed predominantly in astroglial cells and is responsible for 90% of total glutamate uptake. Glutamate transporters tightly regulate glutamate concentration in the synaptic cleft. Dysfunction of EAAT2 and accumulation of excessive extracellular glutamate has been implicated in the development of several neurodegenerative diseases including Alzheimer's disease, Huntington's disease, and amyotrophic lateral sclerosis. Analysis of the 2.5 kb human EAAT2 promoter showed that NF-κB is an important regulator of EAAT2 expression in astrocytes. Screening of approximately 1,040 FDA-approved compounds and nutritionals led to the discovery that many β-lactam antibiotics are transcriptional activators of EAAT2 resulting in increased EAAT2 protein levels. Treatment of animals with ceftriaxone (CEF), a β-lactam antibiotic, led to an increase of EAAT2 expression and glutamate transport activity in the brain. CEF has neuroprotective effects in both in vitro and in vivo models based on its ability to inhibit neuronal cell death by preventing glutamate excitotoxicity. CEF increases EAAT2 transcription in primary human fetal astrocytes through the NF-κB signaling pathway. The NF-κB binding site at -272 position was critical in CEF-mediated EAAT2 protein induction. These studies emphasize the importance of transcriptional regulation in controlling glutamate levels in the brain. They also emphasize the potential utility of the EAAT2 promoter for developing both low and high throughput screening assays to identify novel small molecule regulators of glutamate transport with potential to ameliorate pathological changes occurring during and causing neurodegeneration.
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Affiliation(s)
- Keetae Kim
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, Virginia 23298, USA.
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Moriyama M, Jayakumar AR, Tong XY, Norenberg MD. Role of mitogen-activated protein kinases in the mechanism of oxidant-induced cell swelling in cultured astrocytes. J Neurosci Res 2010; 88:2450-8. [PMID: 20623534 DOI: 10.1002/jnr.22400] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Cytotoxic brain edema, usually a consequence of astrocyte swelling, is an important complication of stroke, traumatic brain injury, hepatic encephalopathy, and other neurological disorders. Although mechanisms underlying astrocyte swelling are not fully understood, oxidative stress (OS) has generally been considered an important factor in its pathogenesis. To better understand the mechanism(s) by which OS causes cell swelling, we examined the potential involvement of mitogen-activated protein kinases (MAPKs) in this process. Cultures exposed to theoxidant H(2)O(2) (10, 25, 50 microM) for different time periods (1-24 hr) significantly increased cell swelling in a triphasic manner. Swelling was initially observed at 10 min (peaking at 30 min), which was followed by cell shrinkage at 1 hr. A subsequent increase in cell volume occurred at approximately 6 hr, and the rise lasted for at least 24 hr. Cultures exposed to H(2)O(2) caused the activation of MAPKs (ERK1/2, JNK and p38-MAPK), whereas inhibition of MAPKs diminished cell swelling induced by 10 and 25 microM H(2)O(2). These findings suggest that activation of MAPKs is an important factor in the mediation of astrocyte swelling following oxidative stress.
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Affiliation(s)
- M Moriyama
- Department of Pathology, University of Miami School of Medicine, Miami, Florida 33101, USA
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Wright G, Soper R, Brooks HF, Stadlbauer V, Vairappan B, Davies NA, Andreola F, Hodges S, Moss RF, Davies DC, Jalan R. Role of aquaporin-4 in the development of brain oedema in liver failure. J Hepatol 2010; 53:91-7. [PMID: 20451280 DOI: 10.1016/j.jhep.2010.02.020] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Revised: 02/01/2010] [Accepted: 02/04/2010] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS Liver failure is associated with progressive cytotoxic brain oedema (astrocyte swelling), which underlies hepatic encephalopathy (HE). Ammonia and superimposed inflammation are key synergistic factors in HE, but the mechanism(s) involved remain unknown. We aimed to determine whether aquaporin-4 (AQP4), an astrocyte endfeet bi-directional water channel, is associated with the brain oedema of HE. METHOD Rats (n=60) received sham-operation (sham), 5 days hyperammonaemia-inducing diet (HD), galactosamine (GALN) induced acute liver failure (ALF), 4 weeks bile duct-ligation (BDL) induced cirrhosis, or caecal ligation and puncture (CLP), a 24h model of bacterial peritonitis. Rats from every group (except CLP) were randomised to receive intraperitoneal injections of lipopolysaccharide (LPS; 1mg/kg) or saline, prior to termination 3h later. Brain water, AQP4 protein expression (western blot) and AQP4 localisation by immunogold electron microscopy were investigated. RESULTS Significant hyperammonaemia was observed in saline-injected BDL (p<0.05), GALN (p<0.01), and HD (p<0.01), compared to sham rats. LPS injection did not affect arterial ammonia or plasma biochemistry in any of the treatment groups. Increased brain water was observed in saline-injected GALN (p<0.05), HD (p<0.01), and CLP (p<0.001) compared to sham rats. Brain water was numerically increased in BDL rats, but this failed to reach significance (p=0.09). LPS treatment further increased oedema significantly in all treatment groups (p<0.05, respectively). AQP4 expression was significantly increased in saline-injected BDL (p<0.05), but not other treatment groups, compared to sham rats. Membrane polarisation was maintained in BDL rats. CONCLUSION The results suggest that AQP4 is not directly associated with the development of brain oedema in liver failure, hyperammonaemia, or sepsis. In cirrhosis, there is increased AQP4 protein expression, but membrane polarisation, is maintained, possibly in a compensatory attempt to limit severe brain oedema.
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Affiliation(s)
- Gavin Wright
- Institute of Hepatology, University College London, London, UK
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Chavarria L, Oria M, Romero-Gimenez J, Alonso J, Lope-Piedrafita S, Cordoba J. Diffusion tensor imaging supports the cytotoxic origin of brain edema in a rat model of acute liver failure. Gastroenterology 2010; 138:1566-73. [PMID: 19843475 DOI: 10.1053/j.gastro.2009.10.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2009] [Revised: 09/15/2009] [Accepted: 10/07/2009] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS Brain edema is a severe complication of acute liver failure (ALF) that has been related to ammonia concentrations. Two mechanisms have been proposed in the pathogenesis: vasogenic edema that is secondary to the breakdown of the blood-brain barrier and cytotoxic edema caused by ammonia metabolites in astrocytes. METHODS We applied magnetic resonance techniques to assess the intracellular or extracellular distribution of brain water and metabolites in a rat model of devascularized ALF. The brain water content was assessed by gravimetry and blood-brain barrier permeability was determined from the transfer constant of (14)C-labeled sucrose. RESULTS Rats with ALF had a progressive decrease in the apparent diffusion coefficient (ADC) in all brain regions. The average decrease in ADC was significant in precoma (-14%) and coma stages (-20%). These changes, which indicate an increase of the intracellular water compartment, were followed by a significant increase in total brain water (coma 82.4% +/- 0.3% vs sham 81.6% +/- 0.3%; P = .0001). Brain concentrations of glutamine (6 hours, 540%; precoma, 851%; coma, 1086%) and lactate (6 hours, 166%; precoma, 998%; coma, 3293%) showed a marked increase in ALF that paralleled the decrease in ADC and neurologic outcome. In contrast, the transfer constant of (14)C-sucrose was unaltered. CONCLUSIONS The pathogenesis of brain edema in an experimental model of ALF involves a cytotoxic mechanism: the metabolism of ammonia in astrocytes induces an increase of glutamine and lactate that appears to mediate cellular swelling. Therapeutic measures should focus on removing ammonia and improving brain energy metabolism.
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Ohara K, Aoyama M, Fujita M, Sobue K, Asai K. Prolonged exposure to ammonia increases extracellular glutamate in cultured rat astrocytes. Neurosci Lett 2009; 462:109-12. [PMID: 19576960 DOI: 10.1016/j.neulet.2009.06.090] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Revised: 06/11/2009] [Accepted: 06/29/2009] [Indexed: 01/09/2023]
Abstract
Abnormal alteration of brain function is a characteristic complication of hepatic encephalopathy in both acute and chronic liver failure. Previous studies suggest that the pathogenesis of hepatic encephalopathy involves chronic glial edema with subsequent alteration of glioneuronal communication, N-methyl-d-aspartate (NMDA) receptor activation, and oxidative/nitrosative stress. In the present study, we investigated extracellular glutamate levels in cultured astrocytes under prolonged exposure to ammonia. Using an enzyme-linked high-performance liquid chromatography assay to detect glutamate, prolonged (48 h) exposure of cultured astrocytes to ammonia resulted in a concentration- and time-dependent increase in extracellular glutamate. Similar increases were observed when ammonia-containing medium (pH 7.8) was adjusted to the pH of control medium (pH 7.4), indicating that the effect is not due to pH. Treatment of astrocytes with an antioxidant (l-ascorbic acid), an NADPH oxidase inhibitor (apocynin), a Ca2+ chelator (BAPTA-AM), an NMDA receptor antagonist (NK801), or a mitochondrial permeability transition inhibitor (cyclosporine A) suppressed the increase of extracellular glutamate in response to prolonged ammonia exposure. Prolonged exposure to ammonia increased extracellular glutamate through the NMDA receptor, increased intracellular Ca2+ levels, and upregulation of excitatory amino acids. The addition of ATP further increased extracellular glutamate levels in astrocytes subjected to prolonged ammonia treatment (5mM, 48 h) in a dose-dependent manner. These results indicate that the deregulation of glutamate release from astrocytes may contribute to the dysfunction of glutamatergic neurons in patients with acute liver failure (ALF).
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Affiliation(s)
- Kentaro Ohara
- Department of Molecular Neurobiology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan
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Chawla R, Smith D, Marik PE. Near fatal posterior reversible encephalopathy syndrome complicating chronic liver failure and treated by induced hypothermia and dialysis: a case report. J Med Case Rep 2009; 3:6623. [PMID: 19830117 PMCID: PMC2726521 DOI: 10.1186/1752-1947-3-6623] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Accepted: 01/22/2009] [Indexed: 02/10/2023] Open
Abstract
Introduction Posterior reversible encephalopathy syndrome is a clinico-neuroradiological entity characterized by headache, vomiting, altered mental status, blurred vision and seizures with neuroimaging studies demonstrating white-gray matter edema involving predominantly the posterior region of the brain. Case presentation We report a 47-year-old Caucasian man with liver cirrhosis who developed posterior reversible encephalopathy syndrome following an upper gastrointestinal hemorrhage and who was managed with induced hypothermia for control of intracranial hypertension and continuous veno-venous hemodiafiltration for severe hyperammonemia. Conclusion We believe this is the first documented case report of posterior reversible encephalopathy syndrome associated with cirrhosis as well as the first report of the use of induced hypothermia and continuous veno-venous hemodiafiltration in this setting.
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Görg B, Qvartskhava N, Keitel V, Bidmon HJ, Selbach O, Schliess F, Häussinger D. Ammonia induces RNA oxidation in cultured astrocytes and brain in vivo. Hepatology 2008; 48:567-79. [PMID: 18506841 DOI: 10.1002/hep.22345] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
UNLABELLED Oxidative stress plays a major role in cerebral ammonia toxicity and the pathogenesis of hepatic encephalopathy (HE). As shown in this study, ammonia induces a rapid RNA oxidation in cultured rat astrocytes, vital mouse brain slices, and rat brain in vivo. Ammonia-induced RNA oxidation in cultured astrocytes is reversible and sensitive to MK-801, 1,2-Bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid, apocynin, epigallocatechin gallate, and polyphenon 60, suggesting the involvement of N-methyl-D-aspartic acid (NMDA) receptor activation, Ca(2+), nicotinamide adenine dinucleotide phosphate, and reduced form (NADPH) oxidase-dependent oxidative stress. Also, hypo-osmolarity, tumor necrosis factor alpha (TNF-alpha), and diazepam increase RNA oxidation in cultured astrocytes, suggesting that the action of different HE-precipitating factors converges at the level of RNA oxidation. Among the oxidized RNA species, 18S-rRNA and the messenger RNA (mRNA) coding for the glutamate/aspartate transporter (GLAST) were identified. Cerebral RNA oxidation in acutely ammonia-loaded rats in vivo is reversible and predominates in neuronal soma and perivascular astrocyte processes. In neuronal dendrites, oxidized RNA colocalizes with the RNA-binding splicing protein neurooncological ventral antigen (NOVA)-2 within putative RNA transport granules, which are also found in close vicinity to postsynaptic spines. This indicates that oxidized RNA species may participate in postsynaptic protein synthesis, which is a biochemical substrate for learning and memory consolidation. Neuronal and astroglial RNA oxidation increases also in vital mouse brain slices treated with ammonia and TNF-alpha, respectively. CONCLUSION Cerebral RNA oxidation is identified as a not yet recognized consequence of acute ammonia intoxication. RNA oxidation may affect gene expression and local protein synthesis and thereby provide another link between reactive oxygen species (ROS)/reactive nitrogen oxide species (RNOS) production and ammonia toxicity.
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Affiliation(s)
- Boris Görg
- Clinic for Gastroenterology, Hepatology and Infectiology, Heinrich-Heine University, Düsseldorf, Germany
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Saraswat VA, Saksena S, Nath K, Mandal P, Singh J, Thomas MA, Rathore RS, Gupta RK. Evaluation of mannitol effect in patients with acute hepatic failure and acute-on-chronic liver failure using conventional MRI, diffusion tensor imaging and in-vivo proton MR spectroscopy. World J Gastroenterol 2008; 14:4168-78. [PMID: 18636662 PMCID: PMC2725378 DOI: 10.3748/wjg.14.4168] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To evaluate the effect of an intravenous bolus of mannitol in altering brain metabolites, brain water content, brain parenchyma volume, cerebrospinal fluid (CSF) volume and clinical signs in controls and in patients with acute liver failure (ALF) and acute-on-chronic liver failure (ACLF), by comparing changes in conventional magnetic resonance imaging (MRI), in vivo proton magnetic resonance spectroscopy (PMRS) and diffusion tensor imaging (DTI) before and after its infusion.
METHODS: Five patients each with ALF and ACLF in grade 3 or 4 hepatic encephalopathy and with clinical signs of raised intracranial pressure were studied along with five healthy volunteers. After baseline MRI, an intravenous bolus of 20% mannitol solution was given over 10 min in controls as well as in patients with ALF and ACLF. Repeat MRI for the same position was acquired 30 min after completing the mannitol injection.
RESULTS: No statistically significant difference was observed between controls and patients with ALF and ACLF in metabolite ratios, DTI metrics and brain volume or CSF volume following 45 min of mannitol infusion. There was no change in clinical status at the end of post-mannitol imaging.
CONCLUSION: The osmotic effect of mannitol did not result in significant reduction of brain water content, alteration in metabolite ratios or any change in the clinical status of these patients during or within 45 min of mannitol infusion.
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Lee SG, Su ZZ, Emdad L, Gupta P, Sarkar D, Borjabad A, Volsky DJ, Fisher PB. Mechanism of ceftriaxone induction of excitatory amino acid transporter-2 expression and glutamate uptake in primary human astrocytes. J Biol Chem 2008; 283:13116-23. [PMID: 18326497 DOI: 10.1074/jbc.m707697200] [Citation(s) in RCA: 234] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Glutamate is an essential neurotransmitter regulating brain functions. Excitatory amino acid transporter (EAAT)-2 is one of the major glutamate transporters primarily expressed in astroglial cells. Dysfunction of EAAT2 is implicated in acute and chronic neurological disorders, including stroke/ischemia, temporal lobe epilepsy, amyotrophic lateral sclerosis, Alzheimer disease, human immunodeficiency virus 1-associated dementia, and growth of malignant gliomas. Ceftriaxone, one of the beta-lactam antibiotics, is a stimulator of EAAT2 expression with neuroprotective effects in both in vitro and in vivo models based in part on its ability to inhibit neuronal cell death by glutamate excitotoxicity. Based on this consideration and its lack of toxicity, ceftriaxone has potential to manipulate glutamate transmission and ameliorate neurotoxicity. We investigated the mechanism by which ceftriaxone enhances EAAT2 expression in primary human fetal astrocytes (PHFA). Ceftriaxone elevated EAAT2 transcription in PHFA through the nuclear factor-kappaB (NF-kappaB) signaling pathway. The antibiotic promoted nuclear translocation of p65 and activation of NF-kappaB. The specific NF-kappaB binding site at the -272 position of the EAAT2 promoter was responsible for ceftriaxone-mediated EAAT2 induction. In addition, ceftriaxone increased glutamate uptake, a primary function of EAAT2, and EAAT2 small interference RNA completely inhibited ceftriaxone-induced glutamate uptake activity in PHFA. Taken together, our data indicate that ceftriaxone is a potent modulator of glutamate transport in PHFA through NF-kappaB-mediated EAAT2 promoter activation. These findings suggest a mechanism for ceftriaxone modulation of glutamate transport and for its potential effects on ameliorating specific neurodegenerative diseases through modulation of extracellular glutamate.
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Affiliation(s)
- Seok-Geun Lee
- Department of Urology, Neurosurgery, and Pathology, Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, New York 10032, USA
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Diagnosis and Management of Liver Failure in the Adult. Crit Care Med 2008. [DOI: 10.1016/b978-032304841-5.50078-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Wright G, Shawcross D, Olde Damink SWM, Jalan R. Brain cytokine flux in acute liver failure and its relationship with intracranial hypertension. Metab Brain Dis 2007; 22:375-88. [PMID: 17899343 DOI: 10.1007/s11011-007-9071-4] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND In acute liver failure (ALF), it is unclear whether the systemic inflammatory response associated with intracranial hypertension is related to brain cytokine production. AIM To determine the relationship of brain cytokine production with severity of intracranial hypertension in ALF patients. METHOD We studied 16 patients with ALF. All patients were mechanically ventilated and cerebral blood flow measured using the Kety-Schmidt technique and intracranial pressure (ICP) measured with a Camino subdural catheter. We sampled blood from an artery and a reverse jugular catheter to measure proinflammatory cytokines (TNF-alpha, IL-6 and IL-1beta) and ammonia. Additionally, in 3 patients, serial samples were obtained over a 72 h period. RESULTS In ALF patients a good correlation between arterial pro-inflammatory cytokines and ICP (r (2) = 0.34, 0.50 and 0.52; for IL-6, IL-1beta and TNF-alpha respectively) was observed. There was a positive cerebral cytokine 'flux' (production), in ALF patients with uncontrolled ICP. Plasma ammonia between groups was not statistically significant. In the ALF patients studied longitudinally, brain proinflammatory cytokine production was associated with uncontrolled ICP. CONCLUSION Our results provide novel data supporting brain production of cytokines in patients with uncontrolled intracranial hypertension indicating activation of the inflammatory cascade in the brain. Also, the appearance of these cytokines in the jugular bulb catheter may indicate a compromised blood brain barrier at this late stage.
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Affiliation(s)
- Gavin Wright
- Liver Failure Group, The Institute of Hepatology, Division of Medicine, University College London, 69-75 Chenies Mews, London, UK
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Abstract
Brain edema is a critical component of hepatic encephalopathy (HE) associated with acute liver failure and such edema appears to be principally due to astrocyte swelling (cytotoxic edema). Ammonia is believed to represent a major factor responsible for astrocyte swelling, although the mechanisms by which ammonia causes such swelling are not completely understood. Recent studies have implicated potential role of oxidative stress, and the mitochondrial permeability transition (mPT). While it is not known how oxidative stress and the mPT cause astrocyte swelling, it is reasonable to suggest that these events may affect one or more plasma membrane proteins involved in water and ion homeostasis in astrocytes. One such protein strongly implicated in brain edema in other neurological conditions is the water channel protein aquaporin-4 (AQP-4), which is abundantly expressed in astrocytes. This article summarizes the potential role of AQP-4 in brain edema in in vivo models of HE, as well as in ammonia-induced cell swelling in cultured astrocytes. The involvement of AQP-4 in the effects of manganese, another toxin implicated in HE, will also be discussed.
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Affiliation(s)
- K V Rama Rao
- Department of Pathology, University of Miami School of Medicine, Miami, FL 33101, USA.
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Acharya SK, Bhatia V. Acute Liver Failure. APOLLO MEDICINE 2007. [DOI: 10.1016/s0976-0016(11)60465-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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