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Felgendreff P, Hosseiniasl SM, Felgendreff L, Amiot BP, Minshew A, Ahmadzada B, Qu Z, Wilken S, Arribas Gomez I, Nyberg SL, Cook CN. Comprehensive analysis of brain injury parameters in a preclinical porcine model of acute liver failure. Front Med (Lausanne) 2024; 11:1363979. [PMID: 38606159 PMCID: PMC11007081 DOI: 10.3389/fmed.2024.1363979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Accepted: 02/21/2024] [Indexed: 04/13/2024] Open
Abstract
Introduction Acute liver failure (ALF) is defined as acute loss of liver function leading to hepatic encephalopathy associated with a high risk of patient death. Brain injury markers in serum and tissue can help detect and monitor ALF-associated brain injury. This study compares different brain injury parameters in plasma and tissue along with the progression of ALF. Method ALF was induced by performing an 85% liver resection. Following the resection, animals were recovered and monitored for up to 48 h or until reaching the predefined endpoint of receiving standard medical therapy (SMT). Blood and serum samples were taken at Tbaseline, T24, and upon reaching the endpoint (Tend). Control animals were euthanized by exsanguination following plasma sampling. Postmortem brain tissue samples were collected from the frontal cortex (FCTx) and cerebellum (Cb) of all animals. Glial fibrillary acidic protein (GFAP) and tau protein and mRNA levels were quantified using ELISA and qRT-PCR in all plasma and brain samples. Plasma neurofilament light (NFL) was also measured using ELISA. Results All ALF animals (n = 4) were euthanized upon showing signs of brain herniation. Evaluation of brain injury biomarkers revealed that GFAP was elevated in ALF animals at T24h and Tend, while Tau and NFL concentrations were unchanged. Moreover, plasma glial fibrillary acidic protein (GFAP) levels were negatively correlated with total protein and positively correlated with both aspartate transaminase (AST) and alkaline phosphatase (AP). Additionally, lower GFAP and tau RNA expressions were observed in the FCTx of the ALF group but not in the CB tissue. Conclusion The current large animal study has identified a strong correlation between GFAP concentration in the blood and markers of ALF. Additionally, the protein and gene expression analyses in the FCTx revealed that this area appears to be susceptible, while the CB is protected from the detrimental impacts of ALF-associated brain swelling. These results warrant further studies to investigate the mechanisms behind this process.
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Affiliation(s)
- Philipp Felgendreff
- Department of Surgery, Mayo Clinic, Rochester, MN, United States
- Department of General, Visceral, and Transplantation Surgery, Hannover Medical School, Hannover, Germany
| | | | - Lisa Felgendreff
- Department of Journalism and Communication Research, Hannover University of Music, Drama, and Media, Hanover, Germany
| | - Bruce P. Amiot
- Department of Surgery, Mayo Clinic, Rochester, MN, United States
| | - Anna Minshew
- Department of Surgery, Mayo Clinic, Rochester, MN, United States
| | | | - Zhi Qu
- Transplant Center, Hannover Medical School, Hannover, Germany
| | - Silvana Wilken
- Department of Surgery, Mayo Clinic, Rochester, MN, United States
| | - Ines Arribas Gomez
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, United States
| | - Scott L. Nyberg
- Department of Surgery, Mayo Clinic, Rochester, MN, United States
- William J. von Liebig Center for Transplantation and Clinical Regeneration, Mayo Clinic, Rochester, MN, United States
| | - Casey N. Cook
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, United States
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Yakubov E, Schmid S, Hammer A, Chen D, Dahlmanns JK, Mitrovic I, Zurabashvili L, Savaskan N, Steiner HH, Dahlmanns M. Ferroptosis and PPAR-gamma in the limelight of brain tumors and edema. Front Oncol 2023; 13:1176038. [PMID: 37554158 PMCID: PMC10406130 DOI: 10.3389/fonc.2023.1176038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 07/04/2023] [Indexed: 08/10/2023] Open
Abstract
Human malignant brain tumors such as gliomas are devastating due to the induction of cerebral edema and neurodegeneration. A major contributor to glioma-induced neurodegeneration has been identified as glutamate. Glutamate promotes cell growth and proliferation in variety of tumor types. Intriguently, glutamate is also an excitatory neurotransmitter and evokes neuronal cell death at high concentrations. Even though glutamate signaling at the receptor and its downstream effectors has been extensively investigated at the molecular level, there has been little insight into how glutamate enters the tumor microenvironment and impacts on metabolic equilibration until recently. Surprisingly, the 12 transmembrane spanning tranporter xCT (SLC7A11) appeared to be a major player in this process, mediating glutamate secretion and ferroptosis. Also, PPARγ is associated with ferroptosis in neurodegeneration, thereby destroying neurons and causing brain swelling. Although these data are intriguing, tumor-associated edema has so far been quoted as of vasogenic origin. Hence, glutamate and PPARγ biology in the process of glioma-induced brain swelling is conceptually challenging. By inhibiting xCT transporter or AMPA receptors in vivo, brain swelling and peritumoral alterations can be mitigated. This review sheds light on the role of glutamate in brain tumors presenting the conceptual challenge that xCT disruption causes ferroptosis activation in malignant brain tumors. Thus, interfering with glutamate takes center stage in forming the basis of a metabolic equilibration approach.
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Affiliation(s)
- Eduard Yakubov
- Department of Neurosurgery, Paracelsus Medical University, Nuremberg, Germany
| | - Sebastian Schmid
- Department of Trauma, Orthopaedics, Plastic and Hand Surgery, University Hospital Augsburg, Augsburg, Germany
| | - Alexander Hammer
- Department of Neurosurgery, Paracelsus Medical University, Nuremberg, Germany
- Center for Spine and Scoliosis Therapy, Malteser Waldkrankenhaus St. Marien, Erlangen, Germany
| | - Daishi Chen
- Department of Otorhinolaryngology, Shenzhen People's Hospital, Jinan University, Shenzhen, China
| | - Jana Katharina Dahlmanns
- Institute for Physiology and Pathophysiology, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Ivana Mitrovic
- Department of Cardiac Surgery, Bogenhausen Hospital, Munich, Germany
| | | | - Nicolai Savaskan
- Department of Neurosurgery, University Medical School Hospital Universitätsklinikum Erlangen (UKER), Friedrich-Alexander Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
- Department of Public Health Neukölln, District Office Neukölln of Berlin Neukölln, Berlin, Germany
| | | | - Marc Dahlmanns
- Institute for Physiology and Pathophysiology, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
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Sepehrinezhad A, Shahbazi A, Sahab Negah S, Stolze Larsen F. New Insight Into Mechanisms of Hepatic Encephalopathy: An Integrative Analysis Approach to Identify Molecular Markers and Therapeutic Targets. Bioinform Biol Insights 2023; 17:11779322231155068. [PMID: 36814683 PMCID: PMC9940182 DOI: 10.1177/11779322231155068] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 01/17/2023] [Indexed: 02/19/2023] Open
Abstract
Hepatic encephalopathy (HE) is a set of complex neurological complications that arise from advanced liver disease. The precise molecular and cellular mechanism of HE is not fully understood. Differentially expressed genes (DEGs) from microarray technologies are powerful approaches to obtain new insight into the pathophysiology of HE. We analyzed microarray data sets of cirrhotic patients with HE from Gene Expression Omnibus to identify DEGs in postmortem cerebral tissues. Consequently, we uploaded significant DEGs into the STRING to specify protein-protein interactions. Cytoscape was used to reconstruct the genetic network and identify hub genes. Target genes were uploaded to different databases to perform comprehensive enrichment analysis and repurpose new therapeutic options for HE. A total of 457 DEGs were identified in 2 data sets totally from 12 cirrhotic patients with HE compared with 12 healthy subjects. We found that 274 genes were upregulated and 183 genes were downregulated. Network analyses on significant DEGs indicated 12 hub genes associated with HE. Enrichment analysis identified fatty acid beta-oxidation, cerebral organic acidurias, and regulation of actin cytoskeleton as main involved pathways associated with upregulated genes; serotonin receptor 2 and ELK-SRF/GATA4 signaling, GPCRs, class A rhodopsin-like, and p38 MAPK signaling pathway were related to downregulated genes. Finally, we predicted 39 probable effective drugs/agents for HE. This study not only confirms main important involved mechanisms of HE but also reveals some yet unknown activated molecular and cellular pathways in human HE. In addition, new targets were identified that could be of value in the future study of HE.
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Affiliation(s)
- Ali Sepehrinezhad
- Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Iran,Neuroscience Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Ali Shahbazi
- Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Iran,Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran,Ali Shahbazi, Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, 1449614535, Iran.
| | - Sajad Sahab Negah
- Neuroscience Research Center, Mashhad University of Medical Sciences, Mashhad, Iran,Department of Neuroscience, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Fin Stolze Larsen
- Department of Hepatology CA-3163, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
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Ashwagandha-loaded nanocapsules improved the behavioral alterations, and blocked MAPK and induced Nrf2 signaling pathways in a hepatic encephalopathy rat model. Drug Deliv Transl Res 2023; 13:252-274. [PMID: 35672652 PMCID: PMC9726678 DOI: 10.1007/s13346-022-01181-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/07/2022] [Indexed: 12/14/2022]
Abstract
Ashwagandha (ASH), a vital herb in Ayurvedic medicine, demonstrated potent preclinical hepato- and neuroprotective effects. However, its efficacy is limited due to low oral bioavailability. Accordingly, we encapsulated ASH extract in chitosan-alginate bipolymeric nanocapsules (ASH-BPNCs) to enhance its physical stability and therapeutic effectiveness in the gastrointestinal tract. ASH-BPNC was prepared by emulsification followed by sonication. The NCs showed small particle size (< 220 nm), zeta-potential of 25.2 mV, relatively high entrapment efficiency (79%), physical stability at acidic and neutral pH, and in vitro release profile that extended over 48 h. ASH-BPNC was then investigated in a thioacetamide-induced hepatic encephalopathy (HE) rat model. Compared with free ASH, ASH-BPNC improved survival, neurological score, general motor activity, and cognitive task-performance. ASH-BPNC restored ALT, AST and ammonia serum levels, and maintained hepatic and brain architecture. ASH-BPNC also restored GSH, MDA, and glutathione synthetase levels, and Nrf2 and MAPK signaling pathways in liver and brain tissues. Moreover, ASH-BPNC downregulated hepatic NF-κB immunohistochemical expression. Moreover, the in vivo biodistribution studies demonstrated that most of the administered ASH-BPNC is accumulated in the brain and hepatic tissues. In conclusion, chitosan-alginate BPNCs enhanced the hepatoprotective and neuroprotective effects of ASH, thus providing a promising therapeutic approach for HE.
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Elsherbini DMA, Ghoneim FM, El-Mancy EM, Ebrahim HA, El-Sherbiny M, El-Shafey M, Al-Serwi RH, Elsherbiny NM. Astrocytes profiling in acute hepatic encephalopathy: Possible enrolling of glial fibrillary acidic protein, tumor necrosis factor-alpha, inwardly rectifying potassium channel (Kir 4.1) and aquaporin-4 in rat cerebral cortex. Front Cell Neurosci 2022; 16:896172. [PMID: 36060277 PMCID: PMC9428715 DOI: 10.3389/fncel.2022.896172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 07/18/2022] [Indexed: 11/13/2022] Open
Abstract
Hepatic encephalopathy (HE) is a neurological disarray manifested as a sequel to chronic and acute liver failure (ALF). A potentially fatal consequence of ALF is brain edema with concomitant astrocyte enlargement. This study aims to outline the role of astrocytes in acute HE and shed light on the most critical mechanisms driving this role. Rats were allocated into two groups. Group 1, the control group, received the vehicle. Group 2, the TAA group, received TAA (300 mg/kg) for 3 days. Serum AST, ALT, and ammonia were determined. Liver and cerebral cortical sections were processed for hematoxylin and eosin staining. Additionally, mRNA expression and immunohistochemical staining of cortical GFAP, TNFα, Kir4.1, and AQP4 were performed. Cortical sections from the TAA group demonstrated neuropil vacuolation and astrocytes enlargement with focal gliosis. GFAP, TNFα, and AQP4 revealed increased mRNA expression, positive immunoreactivity, and a positive correlation to brain water content. In contrast, Kir 4.1 showed decreased mRNA expression and immunoreactivity and a negative correlation to brain water content. In conclusion, our findings revealed altered levels of TNFα, Kir 4.1, GFAP, and AQP4 in HE-associated brain edema. A more significant dysregulation of Kir 4.1 and TNFα was observed compared to AQP4 and GFAP.
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Affiliation(s)
- Dalia Mahmoud Abdelmonem Elsherbini
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Sakaka, Saudi Arabia
- Department of Anatomy, Faculty of Medicine, Mansoura University, Mansoura, Egypt
- *Correspondence: Dalia Mahmoud Abdelmonem Elsherbini,
| | - Fatma M. Ghoneim
- Department of Histology and Cell Biology, Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Eman Mohammed El-Mancy
- Deanship of Common First Year, Jouf University, Sakaka, Saudi Arabia
- Department of Zoology, Faculty of Women for Arts, Science and Education, Ain Shams University, Cairo, Egypt
| | - Hasnaa Ali Ebrahim
- Department of Anatomy, Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Mohamed El-Sherbiny
- Department of Basic Medical Sciences, College of Medicine, AlMaarefa University, Riyadh, Saudi Arabia
- Mohamed El-Sherbiny,
| | - Mohamed El-Shafey
- Department of Anatomy, Faculty of Medicine, Mansoura University, Mansoura, Egypt
- Department of Physiological Sciences, Fakeeh College for Medical Sciences, Jeddah, Saudi Arabia
| | - Rasha Hamed Al-Serwi
- Department of Basic Dental Sciences, College of Dentistry, Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia
| | - Nehal M. Elsherbiny
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Tabuk, Tabuk, Saudi Arabia
- Department of Biochemistry, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt
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Ogaly HA, Abdel-Rahman RF, Mohamed MAE, O A AF, Khattab MS, Abd-Elsalam RM. Thymol ameliorated neurotoxicity and cognitive deterioration in a thioacetamide-induced hepatic encephalopathy rat model; involvement of the BDNF/CREB signaling pathway. Food Funct 2022; 13:6180-6194. [PMID: 35583008 DOI: 10.1039/d1fo04292k] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In the present study, we aimed to delineate the neuroprotective potential of thymol (THY) against neurotoxicity and cognitive deterioration induced by thioacetamide (TAA) in an experimental model of hepatic encephalopathy (HE). Rats received TAA (100 mg kg-1, intraperitoneally injected, three times per week) for two weeks. THY (30 and 60 mg kg-1), and Vit E (100 mg k-1) were administered daily by oral gavage for 30 days after HE induction. Supplementation with THY significantly improved liver function, reduced serum ammonia level, and ameliorated the locomotor and cognitive deficits. THY effectively modulated the alteration in oxidative stress markers, neurotransmitters, and brain ATP content. Histopathology of liver and brain tissues showed that THY had ameliorated TAA-induced damage, astrocyte swelling and brain edema. Furthermore, THY downregulated NF-kB and upregulated GFAP protein expression. In addition, THY significantly promoted CREB and BDNF expression at both mRNA and protein levels, together with enhancing brain cAMP level. In conclusion, THY exerted hepato- and neuroprotective effects against HE by mitigating hepatotoxicity, hyperammonemia and brain ATP depletion via its antioxidant, anti-inflammatory effects in addition to activation of the CREB/BDNF signaling pathway.
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Affiliation(s)
- Hanan A Ogaly
- Department of Chemistry, College of Science, King Khalid University, Abha, Saudi Arabia. .,Department of Biochemistry, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt
| | - Rehab F Abdel-Rahman
- Department of Pharmacology, Medical Research and Clinical Studies Institute, National Research Center, Dokki, Giza, Egypt
| | - Marawan Abd Elbaset Mohamed
- Department of Pharmacology, Medical Research and Clinical Studies Institute, National Research Center, Dokki, Giza, Egypt
| | - Ahmed-Farid O A
- Department of Physiology, National Organization for Drug Control and Research, Giza, Egypt
| | - Marwa S Khattab
- Department of Pathology, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt
| | - Reham M Abd-Elsalam
- Department of Pathology, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt
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7
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Claeys W, Van Hoecke L, Lefere S, Geerts A, Verhelst X, Van Vlierberghe H, Degroote H, Devisscher L, Vandenbroucke RE, Van Steenkiste C. The neurogliovascular unit in hepatic encephalopathy. JHEP Rep 2021; 3:100352. [PMID: 34611619 PMCID: PMC8476774 DOI: 10.1016/j.jhepr.2021.100352] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/14/2021] [Accepted: 07/23/2021] [Indexed: 12/14/2022] Open
Abstract
Hepatic encephalopathy (HE) is a neurological complication of hepatic dysfunction and portosystemic shunting. It is highly prevalent in patients with cirrhosis and is associated with poor outcomes. New insights into the role of peripheral origins in HE have led to the development of innovative treatment strategies like faecal microbiota transplantation. However, this broadening of view has not been applied fully to perturbations in the central nervous system. The old paradigm that HE is the clinical manifestation of ammonia-induced astrocyte dysfunction and its secondary neuronal consequences requires updating. In this review, we will use the holistic concept of the neurogliovascular unit to describe central nervous system disturbances in HE, an approach that has proven instrumental in other neurological disorders. We will describe HE as a global dysfunction of the neurogliovascular unit, where blood flow and nutrient supply to the brain, as well as the function of the blood-brain barrier, are impaired. This leads to an accumulation of neurotoxic substances, chief among them ammonia and inflammatory mediators, causing dysfunction of astrocytes and microglia. Finally, glymphatic dysfunction impairs the clearance of these neurotoxins, further aggravating their effect on the brain. Taking a broader view of central nervous system alterations in liver disease could serve as the basis for further research into the specific brain pathophysiology of HE, as well as the development of therapeutic strategies specifically aimed at counteracting the often irreversible central nervous system damage seen in these patients.
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Key Words
- ABC, ATP-binding cassette
- ACLF, acute-on-chronic liver failure
- AD, acute decompensation
- ALF, acute liver failure
- AOM, azoxymethane
- AQP4, aquaporin 4
- Acute Liver Failure
- Ammonia
- BBB, blood-brain barrier
- BCRP, breast cancer resistance protein
- BDL, bile duct ligation
- Blood-brain barrier
- Brain edema
- CCL, chemokine ligand
- CCR, C-C chemokine receptor
- CE, cerebral oedema
- CLD, chronic liver disease
- CLDN, claudin
- CNS, central nervous system
- CSF, cerebrospinal fluid
- Cirrhosis
- Energy metabolism
- GS, glutamine synthetase
- Glymphatic system
- HE, hepatic encephalopathy
- HO-1, heme oxygenase 1
- IL-, interleukin
- MMP-9, matrix metalloproteinase 9
- MRP, multidrug resistance associated protein
- NGVU
- NGVU, neurogliovascular unit
- NKCC1, Na-K-2Cl cotransporter 1
- Neuroinflammation
- OCLN, occludin
- ONS, oxidative and nitrosative stress
- Oxidative stress
- P-gp, P-glycoprotein
- PCA, portacaval anastomosis
- PSS, portosystemic shunt
- S1PR2, sphingosine-1-phosphate receptor 2
- SUR1, sulfonylurea receptor 1
- Systemic inflammation
- TAA, thioacetamide
- TGFβ, transforming growth factor beta
- TJ, tight junction
- TNF, tumour necrosis factor
- TNFR1, tumour necrosis factor receptor 1
- ZO, zonula occludens
- mPT, mitochondrial pore transition
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Affiliation(s)
- Wouter Claeys
- Hepatology Research Unit, Department of Internal Medicine and Paediatrics, Liver Research Center Ghent, Ghent University, Ghent, Belgium
- Barriers in Inflammation, VIB Center for Inflammation Research, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Lien Van Hoecke
- Barriers in Inflammation, VIB Center for Inflammation Research, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Sander Lefere
- Hepatology Research Unit, Department of Internal Medicine and Paediatrics, Liver Research Center Ghent, Ghent University, Ghent, Belgium
- Gut-Liver Immunopharmacology Unit, Department of Basic and Applied Medical Sciences; Liver Research Center Ghent; Ghent University, Ghent, Belgium
| | - Anja Geerts
- Hepatology Research Unit, Department of Internal Medicine and Paediatrics, Liver Research Center Ghent, Ghent University, Ghent, Belgium
| | - Xavier Verhelst
- Hepatology Research Unit, Department of Internal Medicine and Paediatrics, Liver Research Center Ghent, Ghent University, Ghent, Belgium
| | - Hans Van Vlierberghe
- Hepatology Research Unit, Department of Internal Medicine and Paediatrics, Liver Research Center Ghent, Ghent University, Ghent, Belgium
| | - Helena Degroote
- Hepatology Research Unit, Department of Internal Medicine and Paediatrics, Liver Research Center Ghent, Ghent University, Ghent, Belgium
| | - Lindsey Devisscher
- Gut-Liver Immunopharmacology Unit, Department of Basic and Applied Medical Sciences; Liver Research Center Ghent; Ghent University, Ghent, Belgium
| | - Roosmarijn E. Vandenbroucke
- Barriers in Inflammation, VIB Center for Inflammation Research, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Christophe Van Steenkiste
- Antwerp University, Department of Gastroenterology and Hepatology, Antwerp, Belgium
- Department of Gastroenterology and Hepatology, Maria Middelares Hospital, Ghent, Belgium
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Ochoa-Sanchez R, Tamnanloo F, Rose CF. Hepatic Encephalopathy: From Metabolic to Neurodegenerative. Neurochem Res 2021; 46:2612-2625. [PMID: 34129161 DOI: 10.1007/s11064-021-03372-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Revised: 05/31/2021] [Accepted: 06/03/2021] [Indexed: 12/15/2022]
Abstract
Hepatic encephalopathy (HE) is a neuropsychiatric syndrome of both acute and chronic liver disease. As a metabolic disorder, HE is considered to be reversible and therefore is expected to resolve following the replacement of the diseased liver with a healthy liver. However, persisting neurological complications are observed in up to 47% of transplanted patients. Several retrospective studies have shown that patients with a history of HE, particularly overt-HE, had persistent neurological complications even after liver transplantation (LT). These enduring neurological conditions significantly affect patient's quality of life and continue to add to the economic burden of chronic liver disease on health care systems. This review discusses the journey of the brain through the progression of liver disease, entering the invasive surgical procedure of LT and the conditions associated with the post-transplant period. In particular, it will discuss the vulnerability of the HE brain to peri-operative factors and post-LT conditions which may explain non-resolved neurological impairment following LT. In addition, the review will provide evidence; (i) supporting overt-HE impacts on neurological complications post-LT; (ii) that overt-HE leads to permanent neuronal injury and (iii) the pathophysiological role of ammonia toxicity on astrocyte and neuronal injury/damage. Together, these findings will provide new insights on the underlying mechanisms leading to neurological complications post-LT.
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Affiliation(s)
- Rafael Ochoa-Sanchez
- Hepato-Neuro Laboratory, CRCHUM, Université de Montréal, 900, rue Saint-Denis Pavillon R, R08.422, Montreal, QC, H2X-0A9, Canada
| | - Farzaneh Tamnanloo
- Hepato-Neuro Laboratory, CRCHUM, Université de Montréal, 900, rue Saint-Denis Pavillon R, R08.422, Montreal, QC, H2X-0A9, Canada
| | - Christopher F Rose
- Hepato-Neuro Laboratory, CRCHUM, Université de Montréal, 900, rue Saint-Denis Pavillon R, R08.422, Montreal, QC, H2X-0A9, Canada.
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Ismail FS, Faustmann TJ, Corvace F, Tsvetanova A, Moinfar Z, Faustmann PM. Ammonia induced microglia activation was associated with limited effects on connexin 43 and aquaporin 4 expression in an astrocyte-microglia co-culture model. BMC Neurosci 2021; 22:21. [PMID: 33765917 PMCID: PMC7993489 DOI: 10.1186/s12868-021-00628-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 03/16/2021] [Indexed: 02/08/2023] Open
Abstract
Background Hepatic encephalopathy (HE) is a neurological complication resulting from acute or chronic liver disease. Hyperammonemia leading to astrocyte swelling and cerebral edema in combination with neuroinflammation including microglia activation, mainly contribute to the pathogenesis of HE. However, little is known about microglia and their inflammatory response, as well as their influence on astrocytic channels and astrocyte swelling under hyperammonemia. Objective To investigate the effects of ammonia on the microglial activation and morphology in different set-ups of an in vitro astrocyte-microglia co-culture model. Further, potential effects on glial viability, connexin 43 (Cx43) and aquaporin 4 (AQP4) expression were tested. Methods Primary rat glial co-cultures of astrocytes containing 5% (M5, representing "physiological" conditions) or 30% (M30, representing "pathological" conditions) of microglia were incubated with 3 mM, 5 mM, 10 mM and 20 mM ammonium chloride (NH4Cl) for 6 h and 24 h in order to mimic the conditions of HE. An MTT assay was performed to measure the viability, proliferation and cytotoxicity of cells. The microglial phenotypes were analyzed by immunocytochemistry. The expression of Cx43 and AQP4 were quantified by immunoblot analysis. Results A significant reduction of glial viability was observed in M30 co-cultures after incubation with 20 mM NH4Cl for 6 h, whereas in M5 co-cultures the viability remained unchanged. Microglial activation was detected by immunocytochemistry after incubation with 3 mM, 5 mM and 10 mM NH4Cl for 6 h and 24 h in M5 as well as in M30 co-cultures. The Cx43 expression was slightly increased in M30 co-cultures after 6 h incubation with 5 mM NH4Cl. Also, the AQP4 expression was slightly increased only in M5 co-cultures treated with 10 mM NH4Cl for 6 h. Under the other conditions, Cx43 and AQP4 expression was not affected by NH4Cl. Conclusions The novel aspect of our study was the significant microglial activation and decrease of viability after NH4Cl incubation in different set-ups of an in vitro astrocyte-microglia co-culture model, contributing to better understanding of pathophysiological mechanisms of HE. Hyperammonemia led to limited effects on Cx43 and AQP4 expression, the relevance of these minimal changes should be viewed with caution. Supplementary Information The online version contains supplementary material available at 10.1186/s12868-021-00628-1.
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Affiliation(s)
- Fatme Seval Ismail
- Department of Neurology, University Hospital Knappschaftskrankenhaus Bochum, Ruhr University Bochum, Bochum, Germany.
| | - Timo Jendrik Faustmann
- Department of Psychiatry and Psychotherapy, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
| | - Franco Corvace
- Department of Neuroanatomy and Molecular Brain Research, Ruhr University Bochum, Bochum, Germany
| | - Anamariya Tsvetanova
- Department of Neuroanatomy and Molecular Brain Research, Ruhr University Bochum, Bochum, Germany
| | - Zahra Moinfar
- Department of Neuroanatomy and Molecular Brain Research, Ruhr University Bochum, Bochum, Germany.,International Graduate School of Neuroscience, Ruhr University Bochum, Bochum, Germany
| | - Pedro M Faustmann
- Department of Neuroanatomy and Molecular Brain Research, Ruhr University Bochum, Bochum, Germany.,International Graduate School of Neuroscience, Ruhr University Bochum, Bochum, Germany
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Cheon SY, Song J. The Association between Hepatic Encephalopathy and Diabetic Encephalopathy: The Brain-Liver Axis. Int J Mol Sci 2021; 22:ijms22010463. [PMID: 33466498 PMCID: PMC7796499 DOI: 10.3390/ijms22010463] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/02/2021] [Accepted: 01/03/2021] [Indexed: 12/13/2022] Open
Abstract
Hepatic encephalopathy (HE) is one of the main consequences of liver disease and is observed in severe liver failure and cirrhosis. Recent studies have provided significant evidence that HE shows several neurological symptoms including depressive mood, cognitive dysfunction, impaired circadian rhythm, and attention deficits as well as motor disturbance. Liver disease is also a risk factor for the development of diabetes mellitus. Diabetic encephalopathy (DE) is characterized by cognitive dysfunction and motor impairment. Recent research investigated the relationship between metabolic changes and the pathogenesis of neurological disease, indicating the importance between metabolic organs and the brain. Given that a diverse number of metabolites and changes in the brain contribute to neurologic dysfunction, HE and DE are emerging types of neurologic disease. Here, we review significant evidence of the association between HE and DE, and summarise the common risk factors. This review may provide promising therapeutic information and help to design a future metabolic organ-related study in relation to HE and DE.
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Affiliation(s)
- So Yeong Cheon
- Department of Biotechnology, College of Biomedical & Health Science, Konkuk University, Chungju 27478, Korea;
| | - Juhyun Song
- Department of Anatomy, Chonnam National University Medical School, Hwasun 58128, Jeollanam-do, Korea
- Correspondence: ; Tel.: +82-61-379-2706; Fax: +82-61-375-5834
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11
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Anand AC, Nandi B, Acharya SK, Arora A, Babu S, Batra Y, Chawla YK, Chowdhury A, Chaoudhuri A, Eapen EC, Devarbhavi H, Dhiman RK, Datta Gupta S, Duseja A, Jothimani D, Kapoor D, Kar P, Khuroo MS, Kumar A, Madan K, Mallick B, Maiwall R, Mohan N, Nagral A, Nath P, Panigrahi SC, Pawar A, Philips CA, Prahraj D, Puri P, Rastogi A, Saraswat VA, Saigal S, Shalimar, Shukla A, Singh SP, Verghese T, Wadhawan M. Indian National Association for the Study of Liver Consensus Statement on Acute Liver Failure (Part-2): Management of Acute Liver Failure. J Clin Exp Hepatol 2020; 10:477-517. [PMID: 33029057 PMCID: PMC7527855 DOI: 10.1016/j.jceh.2020.04.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 04/12/2020] [Indexed: 12/12/2022] Open
Abstract
Acute liver failure (ALF) is not an uncommon complication of a common disease such as acute hepatitis. Viral hepatitis followed by antituberculosis drug-induced hepatotoxicity are the commonest causes of ALF in India. Clinically, such patients present with appearance of jaundice, encephalopathy, and coagulopathy. Hepatic encephalopathy (HE) and cerebral edema are central and most important clinical event in the course of ALF, followed by superadded infections, and determine the outcome in these patients. The pathogenesis of encephalopathy and cerebral edema in ALF is unique and multifactorial. Ammonia plays a crucial role in the pathogenesis, and several therapies aim to correct this abnormality. The role of newer ammonia-lowering agents is still evolving. These patients are best managed at a tertiary care hospital with facility for liver transplantation (LT). Aggressive intensive medical management has been documented to salvage a substantial proportion of patients. In those with poor prognostic factors, LT is the only effective therapy that has been shown to improve survival. However, recognizing suitable patients with poor prognosis has remained a challenge. Close monitoring, early identification and treatment of complications, and couseling for transplant form the first-line approach to manage such patients. Recent research shows that use of dynamic prognostic models is better for selecting patients undergoing liver transplantation and timely transplant can save life of patients with ALF with poor prognostic factors.
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Key Words
- ACLF, Acute on Chronic liver Failure
- AKI, Acute kidney injury
- ALF, Acute Liver Failure
- ALFED score
- ALT, alanine transaminase
- AST, aspartate transaminase
- CNS, central nervous system
- CT, Computerized tomography
- HELLP, Hemolysis, elevated liver enzymes, and low platelets
- ICH, Intracrainial hypertension
- ICP, Intracrainial Pressure
- ICU, Intensive care unit
- INR, International normalised ratio
- LAD, Liver assist device
- LDLT, Living donor liver transplantation
- LT, Liver transplantation
- MAP, Mean arterial pressure
- MELD, model for end-stage liver disease
- MLD, Metabolic liver disease
- NAC, N-acetyl cysteine
- PALF, Pediatric ALF
- WD, Wilson's Disease
- acute liver failure
- artificial liver support
- liver transplantation
- plasmapheresis
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Affiliation(s)
- Anil C. Anand
- Department of Gastroenterology, Kaliga Institute of Medical Sciences, Bhubaneswar, 751024, India
| | - Bhaskar Nandi
- Department of Gastroenterology, Sarvodaya Hospital and Research Centre, Faridababd, Haryana, India
| | - Subrat K. Acharya
- Department of Gastroenterology and Hepatology, KIIT University, Patia, Bhubaneswar, Odisha, 751 024, India
| | - Anil Arora
- Institute of Liver Gastroenterology & Pancreatico Biliary Sciences, Sir Ganga Ram Hospital, Rajinder Nagar, New Delhi, 110 060, India
| | - Sethu Babu
- Department of Gastroenterology, Krishna Institute of Medical Sciences, Hyderabad, 500003, India
| | - Yogesh Batra
- Department of Gastroenterology, Indraprastha Apollo Hospital, SaritaVihar, New Delhi, 110 076, India
| | - Yogesh K. Chawla
- Department of Gastroenterology, Kalinga Institute of Medical Sciences (KIMS), Kushabhadra Campus (KIIT Campus-5), Patia, Bhubaneswar, Odisha, 751 024, India
| | - Abhijit Chowdhury
- Department of Hepatology, School of Digestive and Liver Diseases, Institute of Post Graduate Medical Education & Research, Kolkata, 700020, India
| | - Ashok Chaoudhuri
- Hepatology and Liver Transplant, Institute of Liver & Biliary Sciences, D-1 Vasant Kunj, New Delhi, India
| | - Eapen C. Eapen
- Department of Hepatology, Christian Medical College, Vellore, India
| | - Harshad Devarbhavi
- Department of Gastroenterology and Hepatology, St. John's Medical College Hospital, Bangalore, 560034, India
| | - Radha K. Dhiman
- Department of Hepatology, Postgraduate Institute of Medical Education and Research, Chandigarh, 160 012, India
| | - Siddhartha Datta Gupta
- Department of Pathology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110 029, India
| | - Ajay Duseja
- Department of Hepatology, Postgraduate Institute of Medical Education and Research, Chandigarh, 160 012, India
| | - Dinesh Jothimani
- Institute of Liver Disease and Transplantation, Dr Rela Institute and Medical Centre, Chrompet, Chennai, 600044, India
| | | | - Premashish Kar
- Department of Gastroenterology and Hepatology, Max Super Speciality Hospital, Vaishali, Ghaziabad, Uttar Pradesh, 201 012, India
| | - Mohamad S. Khuroo
- Department of Gastroenterology, Dr Khuroo’ s Medical Clinic, Srinagar, Kashmir, India
| | - Ashish Kumar
- Institute of Liver Gastroenterology & Pancreatico Biliary Sciences, Sir Ganga Ram Hospital, Rajinder Nagar, New Delhi, 110 060, India
| | - Kaushal Madan
- Gastroenterology and Hepatology, Max Smart Super Specialty Hospital, Saket, New Delhi, India
| | - Bipadabhanjan Mallick
- Department of Gastroenterology, Kalinga Institute of Medical Sciences, Bhubaneswar, 751024, India
| | - Rakhi Maiwall
- Hepatology Incharge Liver Intensive Care, Institute of Liver & Biliary Sciences, D-1 Vasant Kunj, New Delhi, India
| | - Neelam Mohan
- Department of Pediatric Gastroenterology, Hepatology & Liver Transplantation, Medanta – the MedicityHospital, Sector – 38, Gurgaon, Haryana, India
| | - Aabha Nagral
- Department of Gastroenterology, Apollo and Jaslok Hospital & Research Centre, 15, Dr Deshmukh Marg, Pedder Road, Mumbai, Maharashtra, 400 026, India
| | - Preetam Nath
- Department of Gastroenterology, Kaliga Institute of Medical Sciences, Bhubaneswar, 751024, India
| | - Sarat C. Panigrahi
- Department of Gastroenterology, Kaliga Institute of Medical Sciences, Bhubaneswar, 751024, India
| | - Ankush Pawar
- Liver & Digestive Diseases Institute, Fortis Escorts Hospital, Okhla Road, New Delhi, 110 025, India
| | - Cyriac A. Philips
- The Liver Unit and Monarch Liver Lab, Cochin Gastroenterology Group, Ernakulam Medical Centre, Kochi 682028, Kerala, India
| | - Dibyalochan Prahraj
- Department of Gastroenterology, Kaliga Institute of Medical Sciences, Bhubaneswar, 751024, India
| | - Pankaj Puri
- Department of Hepatology and Gastroenterology, Fortis Escorts Liver & Digestive Diseases Institute (FELDI), Fortis Escorts Hospital, Delhi, India
| | - Amit Rastogi
- Department of Liver Transplantation, Medanta – the MedicityHospital, Sector – 38, Gurgaon, Haryana, India
| | - Vivek A. Saraswat
- Department of Gastroenterology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Raibareli Road, Lucknow, Uttar Pradesh, 226 014, India
| | - Sanjiv Saigal
- Department of Hepatology, Department of Liver Transplantation, India
| | - Shalimar
- Department of Gastroenterology and Human Nutrition Unit, All India Institute of Medical Sciences, New Delhi, 29, India
| | - Akash Shukla
- Department of Gastroenterology, LTM Medical College & Sion Hospital, India
| | - Shivaram P. Singh
- Department of Gastroenterology, SCB Medical College, Dock Road, Manglabag, Cuttack, Odisha, 753 007, India
| | - Thomas Verghese
- Department of Gastroenterology, Government Medical College, Kozikhode, India
| | - Manav Wadhawan
- Institute of Liver & Digestive Diseases and Head of Hepatology & Liver Transplant (Medicine), BLK Super Speciality Hospital, Delhi, India
| | - The INASL Task-Force on Acute Liver Failure
- Department of Gastroenterology, Kaliga Institute of Medical Sciences, Bhubaneswar, 751024, India
- Department of Gastroenterology, Sarvodaya Hospital and Research Centre, Faridababd, Haryana, India
- Department of Gastroenterology and Hepatology, KIIT University, Patia, Bhubaneswar, Odisha, 751 024, India
- Institute of Liver Gastroenterology & Pancreatico Biliary Sciences, Sir Ganga Ram Hospital, Rajinder Nagar, New Delhi, 110 060, India
- Department of Gastroenterology, Krishna Institute of Medical Sciences, Hyderabad, 500003, India
- Department of Gastroenterology, Indraprastha Apollo Hospital, SaritaVihar, New Delhi, 110 076, India
- Department of Gastroenterology, Kalinga Institute of Medical Sciences (KIMS), Kushabhadra Campus (KIIT Campus-5), Patia, Bhubaneswar, Odisha, 751 024, India
- Department of Hepatology, School of Digestive and Liver Diseases, Institute of Post Graduate Medical Education & Research, Kolkata, 700020, India
- Hepatology and Liver Transplant, Institute of Liver & Biliary Sciences, D-1 Vasant Kunj, New Delhi, India
- Department of Hepatology, Christian Medical College, Vellore, India
- Department of Gastroenterology and Hepatology, St. John's Medical College Hospital, Bangalore, 560034, India
- Department of Hepatology, Postgraduate Institute of Medical Education and Research, Chandigarh, 160 012, India
- Department of Pathology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110 029, India
- Institute of Liver Disease and Transplantation, Dr Rela Institute and Medical Centre, Chrompet, Chennai, 600044, India
- Gleneagles Global Hospitals, Hyderabad, Telangana, India
- Department of Gastroenterology and Hepatology, Max Super Speciality Hospital, Vaishali, Ghaziabad, Uttar Pradesh, 201 012, India
- Department of Gastroenterology, Dr Khuroo’ s Medical Clinic, Srinagar, Kashmir, India
- Gastroenterology and Hepatology, Max Smart Super Specialty Hospital, Saket, New Delhi, India
- Department of Gastroenterology, Kalinga Institute of Medical Sciences, Bhubaneswar, 751024, India
- Hepatology Incharge Liver Intensive Care, Institute of Liver & Biliary Sciences, D-1 Vasant Kunj, New Delhi, India
- Department of Pediatric Gastroenterology, Hepatology & Liver Transplantation, Medanta – the MedicityHospital, Sector – 38, Gurgaon, Haryana, India
- Department of Gastroenterology, Apollo and Jaslok Hospital & Research Centre, 15, Dr Deshmukh Marg, Pedder Road, Mumbai, Maharashtra, 400 026, India
- Liver & Digestive Diseases Institute, Fortis Escorts Hospital, Okhla Road, New Delhi, 110 025, India
- The Liver Unit and Monarch Liver Lab, Cochin Gastroenterology Group, Ernakulam Medical Centre, Kochi 682028, Kerala, India
- Department of Hepatology and Gastroenterology, Fortis Escorts Liver & Digestive Diseases Institute (FELDI), Fortis Escorts Hospital, Delhi, India
- Department of Liver Transplantation, Medanta – the MedicityHospital, Sector – 38, Gurgaon, Haryana, India
- Department of Gastroenterology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Raibareli Road, Lucknow, Uttar Pradesh, 226 014, India
- Department of Hepatology, Department of Liver Transplantation, India
- Department of Gastroenterology and Human Nutrition Unit, All India Institute of Medical Sciences, New Delhi, 29, India
- Department of Gastroenterology, LTM Medical College & Sion Hospital, India
- Department of Gastroenterology, SCB Medical College, Dock Road, Manglabag, Cuttack, Odisha, 753 007, India
- Department of Gastroenterology, Government Medical College, Kozikhode, India
- Institute of Liver & Digestive Diseases and Head of Hepatology & Liver Transplant (Medicine), BLK Super Speciality Hospital, Delhi, India
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12
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Sepehrinezhad A, Zarifkar A, Namvar G, Shahbazi A, Williams R. Astrocyte swelling in hepatic encephalopathy: molecular perspective of cytotoxic edema. Metab Brain Dis 2020; 35:559-578. [PMID: 32146658 DOI: 10.1007/s11011-020-00549-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 02/12/2020] [Indexed: 02/06/2023]
Abstract
Hepatic encephalopathy (HE) may occur in patients with liver failure. The most critical pathophysiologic mechanism of HE is cerebral edema following systemic hyperammonemia. The dysfunctional liver cannot eliminate circulatory ammonia, so its plasma and brain levels rise sharply. Astrocytes, the only cells that are responsible for ammonia detoxification in the brain, are dynamic cells with unique phenotypic properties that enable them to respond to small changes in their environment. Any pathological changes in astrocytes may cause neurological disturbances such as HE. Astrocyte swelling is the leading cause of cerebral edema, which may cause brain herniation and death by increasing intracranial pressure. Various factors may have a role in astrocyte swelling. However, the exact molecular mechanism of astrocyte swelling is not fully understood. This article discusses the possible mechanisms of astrocyte swelling which related to hyperammonia, including the possible roles of molecules like glutamine, lactate, aquaporin-4 water channel, 18 KDa translocator protein, glial fibrillary acidic protein, alanine, glutathione, toll-like receptor 4, epidermal growth factor receptor, glutamate, and manganese, as well as inflammation, oxidative stress, mitochondrial permeability transition, ATP depletion, and astrocyte senescence. All these agents and factors may be targeted in therapeutic approaches to HE.
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Affiliation(s)
- Ali Sepehrinezhad
- Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
| | - Asadollah Zarifkar
- Shiraz Neuroscience Research Center and Department of Physiology, Shiraz University of Medical Sciences (SUMS), Shiraz, Iran
| | - Gholamreza Namvar
- Department of Neuroscience and Cognition, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Ali Shahbazi
- Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran.
- Cellular and Molecular Research Center, Iran University of Medical Sciences (IUMS), Tehran, Iran.
| | - Roger Williams
- The Institute of Hepatology London and Foundation for Liver Research, 111 Coldharbour Lane, London, SE5 9NT, UK.
- Faculty of Life Sciences & Medicine, King's College London, London, UK.
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13
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Liotta EM, Kimberly WT. Cerebral edema and liver disease: Classic perspectives and contemporary hypotheses on mechanism. Neurosci Lett 2020; 721:134818. [PMID: 32035166 DOI: 10.1016/j.neulet.2020.134818] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 02/01/2020] [Accepted: 02/03/2020] [Indexed: 02/07/2023]
Abstract
Liver disease is a growing public health concern. Hepatic encephalopathy, the syndrome of brain dysfunction secondary to liver disease, is a frequent complication of both acute and chronic liver disease and cerebral edema (CE) is a key feature. While altered ammonia metabolism is a key contributor to hepatic encephalopathy and CE in liver disease, there is a growing appreciation that additional mechanisms contribute to CE. In this review we will begin by presenting three classic perspectives that form a foundation for a discussion of CE in liver disease: 1) CE is unique to acute liver failure, 2) CE in liver disease is only cytotoxic, and 3) CE in liver disease is primarily an osmotically mediated consequence of ammonia and glutamine metabolism. We will present each classic perspective along with more recent observations that call in to question that classic perspective. After highlighting these areas of debate, we will explore the leading contemporary mechanisms hypothesized to contribute to CE during liver disease.
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Affiliation(s)
- Eric M Liotta
- Northwestern University-Feinberg School of Medicine, Department of Neurology, United States; Northwestern University-Feinberg School of Medicine, Department of Surgery, Division of Organ Transplantation, United States; Northwestern University Transplant Outcomes Research Collaboration, United States.
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14
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Hindeya Gebreyesus H, Gebrehiwot Gebremichael T. The Potential Role of Astrocytes in Parkinson's Disease (PD). Med Sci (Basel) 2020; 8:E7. [PMID: 32012713 PMCID: PMC7151567 DOI: 10.3390/medsci8010007] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 08/08/2019] [Accepted: 08/09/2019] [Indexed: 12/11/2022] Open
Abstract
Astrocytes are multi-functional cells, now recognized as critical participants in many brain functions. They play a critical physiological role in the clearance of neurotransmitters, such as glutamate and gamma-aminobutyric acid (GABA), and in the regulation of K+ from the space of synaptic clefts. Astrocytes also express the excitatory amino acid transporters (EAATs) and aquaporin-4 (AQP4) water channel, which are involved in both physiological functions and neurodegenerative diseases (ND). Some of the ND are the Alzheimer's (AD), Huntington's (HD), Parkinson's diseases (PD), Cerebral edema, amyotrophic lateral sclerosis (ALS), and epilepsy pathological conditions in specific regions of the CNS. Parkinson's disease is the second most common age-related neurodegenerative disorder, characterized by degeneration of dopaminergic neurons of the substantia nigra pars compacta (SNpc). These project to the striatum, forming an important pathway within the basal ganglia. Mostly, PD has no clear etiology, and the mechanism of dopaminergic (DA) neuron loss is not well illustrated. The results of various studies suggest that astrocytes are involved in the pathophysiology of PD. Evidence has shown that the down-regulation of EAAT-2/GLT-1 and AQP4 expression is associated with PD pathogenesis. However, controversial results were reported in different experimental studies about the expression and function of EAAT-2/GLT-1 and AQP4, as well as their colocalization in different brain regions, and their involvement in PD development. Therefore, under neurological disorders, Parkinson's disease is related to the genetic and phenotypic change of astrocytes' biology. In this review, the authors summarized recent their research findings, which revealed the involvement of EAAT-2/GLT-1 and AQP4 expression, the physical interaction between EAAT-2/GLT-1 and AQP4 in astrocyte function, and their potential role in the development of PD in SNpc and Subthalamic nucleus (STN) of the basal ganglia nuclei.
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Affiliation(s)
- Hiluf Hindeya Gebreyesus
- School of Medicine, Biomedical Sciences, College of Health Sciences, Mekelle University, P.O. Box: 1871 Mekelle, Tigray, Ethiopia
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15
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Jaeger V, DeMorrow S, McMillin M. The Direct Contribution of Astrocytes and Microglia to the Pathogenesis of Hepatic Encephalopathy. J Clin Transl Hepatol 2019; 7:352-361. [PMID: 31915605 PMCID: PMC6943208 DOI: 10.14218/jcth.2019.00025] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 10/07/2019] [Accepted: 10/24/2019] [Indexed: 02/06/2023] Open
Abstract
Hepatic encephalopathy is a neurological complication resulting from loss of hepatic function and is associated with poor clinical outcomes. During acute liver failure over 20% of mortality can be associated with the development of hepatic encephalopathy. In patients with liver cirrhosis, 1-year survival for those that develop overt hepatic encephalopathy is under 50%. The pathogenesis of hepatic encephalopathy is complicated due to the multiple disruptions in homeostasis that occur following a reduction in liver function. Of these, elevations of ammonia and neuroinflammation have been shown to play a significant contributing role to the development of hepatic encephalopathy. Disruption of the urea cycle following liver dysfunction leads to elevations of circulating ammonia, which enter the brain and disrupt the functioning of astrocytes. This results in dysregulation of metabolic pathways in astrocytes, oxidative stress and cerebral edema. Besides ammonia, circulating chemokines and cytokines are increased following liver injury, leading to activation of microglia and a subsequent neuroinflammatory response. The combination of astrocyte dysfunction and microglia activation are significant contributing factors to the pathogenesis of hepatic encephalopathy.
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Affiliation(s)
- Victoria Jaeger
- Baylor Scott & White Health, Department of Internal Medicine, Temple, TX, USA
| | - Sharon DeMorrow
- Texas A&M University Health Science Center, Department of Medical Physiology, Temple, TX, USA
- Central Texas Veterans Health Care System, Temple, TX, USA
- University of Texas at Austin, Dell Medical School, Department of Internal Medicine, Austin, TX, USA
- University of Texas at Austin, College of Pharmacy, Austin, TX, USA
| | - Matthew McMillin
- Texas A&M University Health Science Center, Department of Medical Physiology, Temple, TX, USA
- Central Texas Veterans Health Care System, Temple, TX, USA
- University of Texas at Austin, Dell Medical School, Department of Internal Medicine, Austin, TX, USA
- Correspondence to: Matthew McMillin, University of Texas at Austin Dell Medical School, 1601 Trinity Street, Building B, Austin, TX 78701, USA. Tel: +1-512-495-5037, Fax: +1-512-495-5839, E-mail:
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Agarwal AN, Mais DD. Sensitivity and Specificity of Alzheimer Type II Astrocytes in Hepatic Encephalopathy. Arch Pathol Lab Med 2019; 143:1256-1258. [PMID: 31063011 DOI: 10.5858/arpa.2018-0455-oa] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
CONTEXT.— Hepatic encephalopathy (HE) is associated with presence of type II astrocytes in the brain on the basis of observations made in single uncontrolled cases. This finding was subsequently demonstrated by in vitro studies with replication of microenvironment of HE by increase in ammonia levels. However, no human studies have been done correlating HE with type II astrocytes. OBJECTIVE.— To determine the sensitivity and specificity of type II astrocytes in HE. DESIGN.— This is a retrospective cohort study in which cases and controls were included. A database search was conducted to identify potential cases of hepatic encephalopathy during a 3-year period, as well as concomitant cases with altered mental status from other causes, liver disease, both, and neither. The presence of HE was determined according to standard clinical criteria, and a coronal section of basal ganglia was selected for examination from each case. Type II astrocytes were enumerated over 20 random high-power fields (HPFs). RESULTS.— Twenty-one patients with HE were identified, with 35 patient controls (18 females, 38 males). Among the patients with HE there was a mean of 19.8 type II astrocytes in 20 HPFs. Patients with altered mental status without HE had an average of 7.2 type II astrocytes per 20 HPFs, and for those without altered mental status, the average was 2.8. For patients with hepatic insufficiency without HE, the average was 11, while for patients with normal hepatic function, the average was 4.1. Overall, for those without HE, the average was 5.4 type II astrocytes per 20 HPFs. CONCLUSIONS.— At a cutoff of 5 or more type II astrocytes per 20 HPFs, sensitivity for HE was 85.7% and specificity was 68.6%. Alzheimer type II astrocytes were present in all cases of HE but were also present in a wide variety of patients without HE.
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Affiliation(s)
- Apeksha N Agarwal
- From the Department of Pathology, University of Texas Health Science Center at San Antonio
| | - Daniel D Mais
- From the Department of Pathology, University of Texas Health Science Center at San Antonio
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17
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Astroglia in Sepsis Associated Encephalopathy. Neurochem Res 2019; 45:83-99. [PMID: 30778837 PMCID: PMC7089215 DOI: 10.1007/s11064-019-02743-2] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 01/25/2019] [Accepted: 01/28/2019] [Indexed: 01/07/2023]
Abstract
Cellular pathophysiology of sepsis associated encephalopathy (SAE) remains poorly characterised. Brain pathology in SAE, which is manifested by impaired perception, consciousness and cognition, results from multifactorial events, including high levels of systemic cytokines, microbial components and endotoxins, which all damage the brain barriers, instigate neuroinflammation and cause homeostatic failure. Astrocytes, being the principal homeostatic cells of the central nervous system contribute to the brain defence against infection. Forming multifunctional anatomical barriers, astroglial cells maintain brain-systemic interfaces and restrict the damage to the nervous tissue. Astrocytes detect, produce and integrate inflammatory signals between immune cells and cells of brain parenchyma, thus regulating brain immune response. In SAE astrocytes are present in both reactive and astrogliopathic states; balance between these states define evolution of pathology and neurological outcomes. In humans pathophysiology of SAE is complicated by frequent presence of comorbidities, as well as age-related remodelling of the brain tissue with senescence of astroglia; these confounding factors further impact upon SAE progression and neurological deficits.
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18
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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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19
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Dhanda S, Gupta S, Halder A, Sunkaria A, Sandhir R. Systemic inflammation without gliosis mediates cognitive deficits through impaired BDNF expression in bile duct ligation model of hepatic encephalopathy. Brain Behav Immun 2018. [PMID: 29518527 DOI: 10.1016/j.bbi.2018.03.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Chronic liver disease per se induces neuroinflammation that contributes to cognitive deficits in hepatic encephalopathy (HE). However, the processes by which pro-inflammatory molecules result in cognitive impairment still remains unclear. In the present study, a significant increase in the activity of liver function enzymes viz. alanine transaminase (ALT), aspartate transaminase (AST) and alkaline phosphatase (ALP) was observed along with increase in plasma ammonia levels after four weeks of bile duct ligation (BDL) in rats suggesting hepatocellular damage. A significant increase was observed in mRNA expression of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α) and monocyte chemoattractant protein-1 (MCP-1) in brain regions and liver of BDL rats. Concomitantly, IL-6, TNF-α and MCP-1 protein levels were also increased in brain regions, liver and serum of BDL rats suggesting the involvement of blood-brain-axis in inflammatory response. However, a significant decrease was observed in glial fibrillary acidic protein (GFAP) and ionized calcium-binding adaptor molecule-1 (Iba-1) expression at transcriptional and translation level in brain of BDL rats. Immunohistochemical and flowcytometric analysis revealed reduced number of GFAP-immunopositive astrocytes and Iba1-immunopositive microglia in the brain regions of BDL rats. Further, a significant decline was observed in cognitive functions in BDL rats assessed using Morris water maze and novel object recognition tests. Expression of pro and mature form of brain derived neurotrophic factor (BDNF) and its upstream transcription element showed significant reduction in brain of BDL rats. Taken together, the results of the present study suggest that systemic inflammation and reduced expression of BDNF and its upstream transcription factor plays a key role in cognitive decline in HE.
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Affiliation(s)
- Saurabh Dhanda
- Department of Biochemistry, Basic Medical Sciences Block-II, Sector-25, Panjab University, Chandigarh 160014, India
| | - Smriti Gupta
- Department of Biochemistry, Basic Medical Sciences Block-II, Sector-25, Panjab University, Chandigarh 160014, India
| | - Avishek Halder
- Department of Biochemistry, Basic Medical Sciences Block-II, Sector-25, Panjab University, Chandigarh 160014, India
| | - Aditya Sunkaria
- Department of Biochemistry, Basic Medical Sciences Block-II, Sector-25, Panjab University, Chandigarh 160014, India
| | - Rajat Sandhir
- Department of Biochemistry, Basic Medical Sciences Block-II, Sector-25, Panjab University, Chandigarh 160014, India.
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20
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Park J, Masaki T, Mezaki Y, Yokoyama H, Nakamura M, Maehashi H, Fujimi TJ, Gouraud SS, Nagatsuma K, Nakagomi M, Kimura N, Matsuura T. Alpha-1 antichymotrypsin is involved in astrocyte injury in concert with arginine-vasopressin during the development of acute hepatic encephalopathy. PLoS One 2017; 12:e0189346. [PMID: 29216295 PMCID: PMC5720809 DOI: 10.1371/journal.pone.0189346] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 11/24/2017] [Indexed: 01/09/2023] Open
Abstract
Background and aims We developed a bio-artificial liver (BAL) using a radial-flow bioreactor and rescued mini-pig models with lethal acute liver failure (ALF). The point of the rescue is the recovery from hepatic encephalopathy (HE). HE on ALF has sometimes resulted in brain death following brain edema with astrocyte swelling. Several factors, including ammonia and glutamine, have been reported to induce astrocyte swelling and injury. However, many clinicians believe that there are any other factors involved in the development of HE. Therefore, the aim of this study was to identify novel HE-inducible factors, particularly those inducing astrocyte dysfunction. Methods Mini-pig plasma samples were collected at three time points: before the administration of toxins (α-amanitin and LPS), when HE occurred after the administration of toxins, and after treatment with extracorporeal circulation (EC) by the BAL. To identify the causative factors of HE, each plasma sample was subjected to a comparative proteome analysis with two-dimensional gel electrophoresis and mass spectrometry. To assess the direct effects of candidate factors on the astrocyte function and injury, in vitro experiments with human astrocytes were performed. Results Using a proteome analysis, we identified alpha-1 antichymotrypsin (ACT), which was increased in plasma samples from mini-pigs with HE and decreased in those after treatment with EC by BAL. In in vitro experiments with human astrocytes, ACT showed growth-inhibitory and cytotoxic effects on astrocytes. In addition, the expression of water channel protein aquaporin-4, which is induced in injured astrocytes, was increased following ACT treatment. Interestingly, these effects of ACT were additively enhanced by adding arginine-vasopressin (AVP) and were canceled by adding an AVP receptor antagonist. Conclusions These results suggest that ACT is involved in astrocyte injury and dysfunction in concert with AVP during the development of acute HE.
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Affiliation(s)
- Jonghyuk Park
- Department of Laboratory Medicine, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Takahiro Masaki
- Department of Laboratory Medicine, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Yoshihiro Mezaki
- Department of Laboratory Medicine, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Hiroshi Yokoyama
- Department of Laboratory Medicine, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Mariko Nakamura
- Department of Laboratory Medicine, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Haruka Maehashi
- Department of Laboratory Medicine, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Takahiko J. Fujimi
- Faculty of Health and Nutrition, Bunkyo University, Chigasaki, Kanagawa, Japan
| | - Sabine S. Gouraud
- Department of Biology, Faculty of Science, Ochanomizu University, Bunkyo-ku, Tokyo, Japan
| | - Keisuke Nagatsuma
- Department of Laboratory Medicine, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Madoka Nakagomi
- Hatano Research Institute, Food and Drug Safety Center, Hadano, Kanagawa, Japan
| | - Naofumi Kimura
- Department of Pharmacology, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Tomokazu Matsuura
- Department of Laboratory Medicine, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
- * E-mail:
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21
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Dhanda S, Sandhir R. Blood-Brain Barrier Permeability Is Exacerbated in Experimental Model of Hepatic Encephalopathy via MMP-9 Activation and Downregulation of Tight Junction Proteins. Mol Neurobiol 2017; 55:3642-3659. [PMID: 28523565 DOI: 10.1007/s12035-017-0521-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 04/06/2017] [Indexed: 12/27/2022]
Abstract
The present study was designed to investigate the mechanisms involved in blood-brain barrier (BBB) permeability in bile duct ligation (BDL) model of chronic hepatic encephalopathy (HE). Four weeks after BDL surgery, a significant increase was observed in serum bilirubin levels. Masson trichrome staining revealed severe hepatic fibrosis in the BDL rats. 99mTc-mebrofenin retention was increased in the liver of BDL rats suggesting impaired hepatobiliary transport. An increase in permeability to sodium fluorescein, Evans blue, and fluorescein isothiocyanate (FITC)-dextran along with increase in water and electrolyte content was observed in brain regions of BDL rats suggesting disrupted BBB. Increased brain water content can be attributed to increase in aquaporin-4 mRNA and protein expression in BDL rats. Matrix metalloproteinase-9 (MMP-9) mRNA and protein expression was increased in brain regions of BDL rats. Additionally, mRNA and protein expression of tissue inhibitor of matrix metalloproteinases (TIMPs) was also increased in different regions of brain. A significant decrease in mRNA expression and protein levels of tight junction proteins, viz., occludin, claudin-5, and zona occluden-1 (ZO-1) was observed in different brain regions of BDL rats. VCAM-1 mRNA and protein expression was also found to be significantly upregulated in different brain regions of BDL animals. The findings from the study suggest that increased BBB permeability in HE involves activation of MMP-9 and loss of tight junction proteins.
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Affiliation(s)
- Saurabh Dhanda
- Department of Biochemistry, Basic Medical Science Block-II, Sector-25, Panjab University, Chandigarh, 160014, India
| | - Rajat Sandhir
- Department of Biochemistry, Basic Medical Science Block-II, Sector-25, Panjab University, Chandigarh, 160014, India.
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22
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Palenzuela L, Oria M, Romero-Giménez J, Garcia-Lezana T, Chavarria L, Cordoba J. Gene expression profiling of brain cortex microvessels may support brain vasodilation in acute liver failure rat models. Metab Brain Dis 2016; 31:1405-1417. [PMID: 27406245 DOI: 10.1007/s11011-016-9863-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 06/19/2016] [Indexed: 12/13/2022]
Abstract
Development of brain edema in acute liver failure can increase intracranial pressure, which is a severe complication of the disease. However, brain edema is neither entirely cytotoxic nor vasogenic and the specific action of the brain microvasculature is still unknown. We aimed to analyze gene expression of brain cortex microvessels in two rat models of acute liver failure. In order to identify global gene expression changes we performed a broad transcriptomic approach in isolated brain cortex microvessels from portacaval shunted rats after hepatic artery ligation (HAL), hepatectomy (HEP), or sham by array hybridization and confirmed changes in selected genes by RT-PCR. We found 157 and 270 up-regulated genes and 143 and 149 down-regulated genes in HAL and HEP rats respectively. Western blot and immunohistochemical assays were performed in cortex and ELISA assays to quantify prostaglandin E metabolites were performed in blood of the sagittal superior sinus. We Identified clusters of differentially expressed genes involving inflammatory response, transporters-channels, and homeostasis. Up-regulated genes at the transcriptional level were associated with vasodilation (prostaglandin-E synthetase, prostaglandin-E receptor, adrenomedullin, bradykinin receptor, adenosine transporter), oxidative stress (hemoxygenase, superoxide dismutase), energy metabolism (lactate transporter) and inflammation (haptoglobin). The only down-regulated tight junction protein was occludin but slightly. Prostaglandins levels were increased in cerebral blood with progression of liver failure. In conclusion, in acute liver failure, up-regulation of several genes at the level of microvessels might suggest an involvement of energy metabolism accompanied by cerebral vasodilation in the cerebral edema at early stages.
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Affiliation(s)
- Lluis Palenzuela
- Servei de Medicina Interna-Hepatologia, Valld'Hebron Institut de Recerca (VH-IR), Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain
- Departament de Medicina, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Marc Oria
- Servei de Medicina Interna-Hepatologia, Valld'Hebron Institut de Recerca (VH-IR), Barcelona, Spain.
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain.
- Departament de Medicina, Universitat Autònoma de Barcelona, Barcelona, Spain.
- Center for Fetal, Cellular and Mollecular Therapy, Division of Pediatric General and Thoracic Surgery, Cincinnati Children's Hospital Medical Center (CCHMC), Cincinnati, OH, USA.
| | - Jordi Romero-Giménez
- Servei de Medicina Interna-Hepatologia, Valld'Hebron Institut de Recerca (VH-IR), Barcelona, Spain
- Departament de Medicina, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Teresa Garcia-Lezana
- Servei de Medicina Interna-Hepatologia, Valld'Hebron Institut de Recerca (VH-IR), Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain
- Departament de Medicina, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Laia Chavarria
- Servei de Medicina Interna-Hepatologia, Valld'Hebron Institut de Recerca (VH-IR), Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain
- Departament de Medicina, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Juan Cordoba
- Servei de Medicina Interna-Hepatologia, Valld'Hebron Institut de Recerca (VH-IR), Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain
- Departament de Medicina, Universitat Autònoma de Barcelona, Barcelona, Spain
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Souto PA, Marcotegui AR, Orbea L, Skerl J, Perazzo JC. Hepatic encephalopathy: Ever closer to its big bang. World J Gastroenterol 2016; 22:9251-9256. [PMID: 27895414 PMCID: PMC5107690 DOI: 10.3748/wjg.v22.i42.9251] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 09/15/2016] [Accepted: 10/19/2016] [Indexed: 02/06/2023] Open
Abstract
Hepatic encephalopathy (HE) is a neuropsychiatric disorder that commonly complicates the course of patients with liver disease. Despite the fact that the syndrome was probably first recognized hundreds of years ago, the exact pathogenesis still remains unclear. Minimal hepatic encephalopathy (MHE) is the earliest form of HE and is estimated to affect more that 75% of patients with liver cirrhosis. It is characterized by cognitive impairment predominantly attention, reactiveness and integrative function with very subtle clinical manifestations. The development of MHE is associated with worsen in driving skills, daily activities and the increase of overall mortality. Skeletal muscle has the ability to shift from ammonia producer to ammonia detoxifying organ. Due to its large size, becomes the main ammonia detoxifying organ in case of chronic liver failure and muscular glutamine-synthase becomes important due to the failing liver and brain metabolic activity. Gut is the major glutamine consumer and ammonia producer organ in the body. Hepatocellular dysfunction due to liver disease, results in an impaired clearance of ammonium and in its inter-organ trafficking. Intestinal bacteria, can also represent an extra source of ammonia production and in cirrhosis, small intestinal bacterial overgrowth and symbiosis can be observed. In the study of HE, to get close to MHE is to get closer to its big bang; and from here, to travel less transited roads such as skeletal muscle and intestine, is to go even closer. The aim of this editorial is to expose this road for further and deeper work.
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Butterworth RF. Pathogenesis of hepatic encephalopathy and brain edema in acute liver failure. J Clin Exp Hepatol 2015; 5:S96-S103. [PMID: 26041966 PMCID: PMC4442857 DOI: 10.1016/j.jceh.2014.02.004] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Accepted: 02/07/2014] [Indexed: 12/12/2022] Open
Abstract
Neuropathologic investigations in acute liver failure (ALF) reveal significant alterations to neuroglia consisting of swelling of astrocytes leading to cytotoxic brain edema and intracranial hypertension as well as activation of microglia indicative of a central neuroinflammatory response. Increased arterial ammonia concentrations in patients with ALF are predictors of patients at risk for the development of brain herniation. Molecular and spectroscopic techniques in ALF reveal alterations in expression of an array of genes coding for neuroglial proteins involved in cell volume regulation and mitochondrial function as well as in the transport of neurotransmitter amino acids and in the synthesis of pro-inflammatory cytokines. Liver-brain pro-inflammatory signaling mechanisms involving transduction of systemically-derived cytokines, ammonia neurotoxicity and exposure to increased brain lactate have been proposed. Mild hypothermia and N-Acetyl cysteine have both hepato-protective and neuro-protective properties in ALF. Potentially effective anti-inflammatory agents aimed at control of encephalopathy and brain edema in ALF include etanercept and the antibiotic minocycline, a potent inhibitor of microglial activation. Translation of these potentially-interesting findings to the clinic is anxiously awaited.
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Key Words
- ALF, acute liver failure
- ATP, adenosine triphosphate
- BBB, blood-brain barrier
- CCL2, chemokine ligand-2
- CMRO2, cerebral metabolic rate for oxygen
- CNS, central nervous system
- EEG, electroencephalography
- GABA, gamma-aminobutyric acid
- GFAP, glial fibrillary acidic protein
- IgG, immunoglobulin
- MRS, magnetic resonance spectroscopy
- NAC, N-Acetyl cysteine
- NMDA, N-methyl-d-aspartate
- SIRS, systemic inflammatory response syndrome
- SNATs, several neutral amino acid transport systems
- TLP, translocator protein
- TNFα, tumor necrosis factor alpha
- acute liver failure
- hepatic encephalopathy
- intracranial hypertension
- microglial activation
- neuroinflammation
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Affiliation(s)
- Roger F. Butterworth
- Neuroscience Research Unit, Hopital St-Luc (CHUM) and Department of Medicine, University of Montreal, Montreal, QC H2W 3J4, Canada,Address for correspondence: Roger F. Butterworth, Neuroscience Research Unit, Hospital St-Luc (CHUM) and Department of Medicine, University of Montreal, 1058 St Denis, Montreal, QC H2W 3J4, Canada. Tel.: +1 902 929 2470.
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Rama Rao KV, Jayakumar AR, Norenberg MD. Brain edema in acute liver failure: mechanisms and concepts. Metab Brain Dis 2014; 29:927-36. [PMID: 24567229 DOI: 10.1007/s11011-014-9502-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 02/05/2014] [Indexed: 12/18/2022]
Abstract
Brain edema and associated increase in intracranial pressure continue to be lethal complications of acute liver failure (ALF). Abundant evidence suggests that the edema in ALF is largely cytotoxic brought about by swelling of astrocytes. Elevated blood and brain ammonia levels have been strongly implicated in the development of the brain edema. Additionally, inflammation and sepsis have been shown to contribute to the astrocyte swelling/brain edema in the setting of ALF. We posit that ammonia initiates a number of signaling events, including oxidative/nitrative stress (ONS), the mitochondrial permeability transition (mPT), activation of the transcription factor (NF-κB) and signaling kinases, all of which have been shown to contribute to the mechanism of astrocyte swelling. All of these factors also impact ion-transporters, including Na(+), K(+), Cl(-) cotransporter and the sulfonylurea receptor 1, as well as the water channel protein aquaporin-4 resulting in a perturbation of cellular ion and water homeostasis, ultimately resulting in astrocyte swelling/brain edema. All of these events are also potentiated by inflammation. This article reviews contemporary knowledge regarding mechanisms of astrocyte swelling/brain edema formation which hopefully will facilitate the identification of therapeutic targets capable of mitigating the brain edema associated with ALF.
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Affiliation(s)
- Kakulavarapu V Rama Rao
- Department of Pathology, University of Miami Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA,
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Aquaporin-4 deletion in mice reduces encephalopathy and brain edema in experimental acute liver failure. Neurobiol Dis 2013; 63:222-8. [PMID: 24321433 DOI: 10.1016/j.nbd.2013.11.018] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 11/05/2013] [Accepted: 11/26/2013] [Indexed: 01/23/2023] Open
Abstract
Brain edema and associated astrocyte swelling leading to increased intracranial pressure are hallmarks of acute liver failure (ALF). Elevated blood and brain levels of ammonia have been implicated in the development of brain edema in ALF. Cultured astrocytes treated with ammonia have been shown to undergo cell swelling and such swelling was associated with an increase in the plasma membrane expression of aquaporin-4 (AQP4) protein. Further, silencing the AQP4 gene in cultured astrocytes was shown to prevent the ammonia-induced cell swelling. Here, we examined the evolution of brain edema in AQP4-null mice and their wild type counterparts (WT-mice) in different models of ALF induced by thioacetamide (TAA) or acetaminophen (APAP). Induction of ALF with TAA or APAP significantly increased brain water content in WT mice (by 1.6% ± 0.3 and 2.3 ± 0.4%, respectively). AQP4 protein was significantly increased in brain plasma membranes of WT mice with ALF induced by either TAA or APAP. In contrast to WT-mice, brain water content did not increase in AQP4-null mice. Additionally, AQP4-null mice treated with either TAA or APAP showed a remarkably lesser degree of neurological deficits as compared to WT mice; the latter displayed an inability to maintain proper gait, and demonstrated a markedly reduced exploratory behavior, with the mice remaining in one corner of the cage with its head tilted downwards. These results support a central role of AQP4 in the brain edema associated with ALF.
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