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Cabrera-Pastor A. Extracellular Vesicles as Mediators of Neuroinflammation in Intercellular and Inter-Organ Crosstalk. Int J Mol Sci 2024; 25:7041. [PMID: 39000150 PMCID: PMC11241119 DOI: 10.3390/ijms25137041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Revised: 06/20/2024] [Accepted: 06/22/2024] [Indexed: 07/16/2024] Open
Abstract
Neuroinflammation, crucial in neurological disorders like Alzheimer's disease, multiple sclerosis, and hepatic encephalopathy, involves complex immune responses. Extracellular vesicles (EVs) play a pivotal role in intercellular and inter-organ communication, influencing disease progression. EVs serve as key mediators in the immune system, containing molecules capable of activating molecular pathways that exacerbate neuroinflammatory processes in neurological disorders. However, EVs from mesenchymal stem cells show promise in reducing neuroinflammation and cognitive deficits. EVs can cross CNS barriers, and peripheral immune signals can influence brain function via EV-mediated communication, impacting barrier function and neuroinflammatory responses. Understanding EV interactions within the brain and other organs could unveil novel therapeutic targets for neurological disorders.
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Affiliation(s)
- Andrea Cabrera-Pastor
- Departamento de Farmacología, Facultad de Medicina y Odontología, Universitat de València, 46010 Valencia, Spain; or
- Fundación de Investigación del Hospital Clínico Universitario de Valencia, INCLIVA, 46010 Valencia, Spain
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2
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Izquierdo-Altarejos P, Arenas YM, Martínez-García M, Vázquez L, Mincheva G, Doverskog M, Blackburn TP, Bohnen NI, Llansola M, Felipo V. Golexanolone reduces glial activation in the striatum and improves non-motor and some motor alterations in a rat model of Parkinson's disease. Front Aging Neurosci 2024; 16:1417938. [PMID: 38974902 PMCID: PMC11224447 DOI: 10.3389/fnagi.2024.1417938] [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: 04/15/2024] [Accepted: 06/03/2024] [Indexed: 07/09/2024] Open
Abstract
Background Parkinson's disease (PD) affects more than 6 million people worldwide. Along with motor impairments, patients and animal models exhibiting PD symptoms also experience cognitive impairment, fatigue, anxiety, and depression. Currently, there are no drugs available for PD that alter the progression of the disease. A body of evidence suggests that increased GABA levels contribute to the reduced expression of tyrosine hydroxylase (TH) and accompanying behavioral deficits. TH expression may be restored by blocking GABAA receptors. We hypothesized that golexanolone (GR3027), a well-tolerated GABAA receptor-modulating steroid antagonist (GAMSA), may improve Parkinson's symptoms in a rat model of PD. Objectives The aims of this study were to assess whether golexanolone can ameliorate motor and non-motor symptoms in a rat model of PD and to identify some underlying mechanisms. Methods We used the unilateral 6-OHDA rat model of PD. The golexanolone treatment started 4 weeks after surgery. Motor symptoms were assessed using Motorater and CatWalk tests. We also analyzed fatigue (using a treadmill test), anhedonia (via the sucrose preference test), anxiety (with an open field test), and short-term memory (using a Y maze). Glial activation and key proteins involved in PD pathogenesis were analyzed using immunohistochemistry and Western blot. Results Rats with PD showed motor incoordination and impaired locomotor gait, increased fatigue, anxiety, depression, and impaired short-term memory. Golexanolone treatment led to improvements in motor incoordination, certain aspects of locomotor gait, fatigue, anxiety, depression, and short-term memory. Notably, golexanolone reduced the activation of microglia and astrocytes, mitigated TH loss at 5 weeks after surgery, and prevented the increase of α-synuclein levels at 10 weeks. Conclusions Golexanolone may be useful in improving both motor and non-motor symptoms that adversely affect the quality of life in PD patients, such as anxiety, depression, fatigue, motor coordination, locomotor gait, and certain cognitive alterations.
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Affiliation(s)
| | - Yaiza M. Arenas
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - Mar Martínez-García
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - Lola Vázquez
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - Gergana Mincheva
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | | | | | - Nicolaas I. Bohnen
- Department of Radiology, University of Michigan, Ann Arbor, MI, United States
- Neurology Service and GRECC, Veterans Administration Ann Arbor Healthcare System, Ann Arbor, MI, United States
- Morris K. Udall Center of Excellence for Parkinson's Disease Research, University of Michigan, Ann Arbor, MI, United States
- Parkinson's Foundation Center of Excellence, University of Michigan, Ann Arbor, MI, United States
| | - Marta Llansola
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - Vicente Felipo
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
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Bäckström T, Doverskog M, Blackburn TP, Scharschmidt BF, Felipo V. Allopregnanolone and its antagonist modulate neuroinflammation and neurological impairment. Neurosci Biobehav Rev 2024; 161:105668. [PMID: 38608826 DOI: 10.1016/j.neubiorev.2024.105668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 03/18/2024] [Accepted: 04/07/2024] [Indexed: 04/14/2024]
Abstract
Neuroinflammation accompanies several brain disorders, either as a secondary consequence or as a primary cause and may contribute importantly to disease pathogenesis. Neurosteroids which act as Positive Steroid Allosteric GABA-A receptor Modulators (Steroid-PAM) appear to modulate neuroinflammation and their levels in the brain may vary because of increased or decreased local production or import from the systemic circulation. The increased synthesis of steroid-PAMs is possibly due to increased expression of the mitochondrial cholesterol transporting protein (TSPO) in neuroinflammatory tissue, and reduced production may be due to changes in the enzymatic activity. Microglia and astrocytes play an important role in neuroinflammation, and their production of inflammatory mediators can be both activated and inhibited by steroid-PAMs and GABA. What is surprising is the finding that both allopregnanolone, a steroid-PAM, and golexanolone, a novel GABA-A receptor modulating steroid antagonist (GAMSA), can inhibit microglia and astrocyte activation and normalize their function. This review focuses on the role of steroid-PAMs in neuroinflammation and their importance in new therapeutic approaches to CNS and liver disease.
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Affiliation(s)
| | | | | | | | - Vicente Felipo
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
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Llansola M. Preface for the Vicente Felipo Honorary Issue of Neurochemical Research. Neurochem Res 2024; 49:1421-1426. [PMID: 38641758 DOI: 10.1007/s11064-024-04139-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2024]
Affiliation(s)
- Marta Llansola
- Laboratory of Neurobiology, Principe Felipe Research Center, Valencia, Spain.
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5
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Wang DS, Ju L, Pinguelo AG, Kaneshwaran K, Haffey SC, Lecker I, Gohil H, Wheeler MB, Kaustov L, Ariza A, Yu M, Volchuk A, Steinberg BE, Goldenberg NM, Orser BA. Crosstalk between GABA A receptors in astrocytes and neurons triggered by general anesthetic drugs. Transl Res 2024; 267:39-53. [PMID: 38042478 DOI: 10.1016/j.trsl.2023.11.007] [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: 08/18/2023] [Revised: 11/17/2023] [Accepted: 11/29/2023] [Indexed: 12/04/2023]
Abstract
General anesthetic drugs cause cognitive deficits that persist after the drugs have been eliminated. Astrocytes may contribute to such cognition-impairing effects through the release of one or more paracrine factors that increase a tonic inhibitory conductance generated by extrasynaptic γ-aminobutyric acid type A (GABAA) receptors in hippocampal neurons. The mechanisms underlying this astrocyte-to-neuron crosstalk remain unknown. Interestingly, astrocytes express anesthetic-sensitive GABAA receptors. Here, we tested the hypothesis that anesthetic drugs activate astrocytic GABAA receptors to initiate crosstalk leading to a persistent increase in extrasynaptic GABAA receptor function in neurons. We also investigated the signaling pathways in neurons and aimed to identify the paracrine factors released from astrocytes. Astrocytes and neurons from mice were grown in primary cell cultures and studied using in vitro electrophysiological and biochemical assays. We discovered that the commonly used anesthetics etomidate (injectable) and sevoflurane (inhaled) stimulated astrocytic GABAA receptors, which in turn promoted the release paracrine factors, that increased the tonic current in neurons via a p38 MAPK-dependent signaling pathway. The increase in tonic current was mimicked by exogenous IL-1β and abolished by blocking IL-1 receptors; however, unexpectedly, IL-1β and other cytokines were not detected in astrocyte-conditioned media. In summary, we have identified a novel form of crosstalk between GABAA receptors in astrocytes and neurons that engages a p38 MAPK-dependent pathway. Brief commentary BACKGROUND: Many older patients experience cognitive deficits after surgery. Anesthetic drugs may be a contributing factor as they cause a sustained increase in the function of "memory blocking" extrasynaptic GABAA receptors in neurons. Interestingly, astrocytes are required for this increase; however, the mechanisms underlying the astrocyte-to-neuron crosstalk remain unknown. TRANSLATIONAL SIGNIFICANCE: We discovered that commonly used general anesthetic drugs stimulate GABAA receptors in astrocytes, which in turn release paracrine factors that trigger a persistent increase in extrasynaptic GABAA receptor function in neurons via p38 MAPK. This novel form of crosstalk may contribute to persistent cognitive deficits after general anesthesia and surgery.
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Affiliation(s)
- Dian-Shi Wang
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Li Ju
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Arsène G Pinguelo
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Kirusanthy Kaneshwaran
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Sean C Haffey
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Irene Lecker
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Himaben Gohil
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Michael B Wheeler
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada; Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Lilia Kaustov
- Department of Anesthesia, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
| | - Anthony Ariza
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - MeiFeng Yu
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Allen Volchuk
- Program in Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Benjamin E Steinberg
- Program in Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada; Department of Anesthesia and Pain Medicine, Hospital for Sick Children, Toronto, Ontario, Canada; Department of Anesthesiology & Pain Medicine, Temerty Faculty of Medicine, University of Toronto, Room 3318, Medical Sciences Building, 1 King's College Circle, Ontario M5S 1A8, Canada
| | - Neil M Goldenberg
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada; Department of Anesthesia and Pain Medicine, Hospital for Sick Children, Toronto, Ontario, Canada; Department of Anesthesiology & Pain Medicine, Temerty Faculty of Medicine, University of Toronto, Room 3318, Medical Sciences Building, 1 King's College Circle, Ontario M5S 1A8, Canada; Program in Neurosciences & Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Beverley A Orser
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada; Department of Anesthesia, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada; Department of Anesthesiology & Pain Medicine, Temerty Faculty of Medicine, University of Toronto, Room 3318, Medical Sciences Building, 1 King's College Circle, Ontario M5S 1A8, Canada.
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Llansola M, Arenas YM, Sancho-Alonso M, Mincheva G, Palomares-Rodriguez A, Doverskog M, Izquierdo-Altarejos P, Felipo V. Neuroinflammation alters GABAergic neurotransmission in hyperammonemia and hepatic encephalopathy, leading to motor incoordination. Mechanisms and therapeutic implications. Front Pharmacol 2024; 15:1358323. [PMID: 38560359 PMCID: PMC10978603 DOI: 10.3389/fphar.2024.1358323] [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: 12/19/2023] [Accepted: 02/29/2024] [Indexed: 04/04/2024] Open
Abstract
Enhanced GABAergic neurotransmission contributes to impairment of motor coordination and gait and of cognitive function in different pathologies, including hyperammonemia and hepatic encephalopathy. Neuroinflammation is a main contributor to enhancement of GABAergic neurotransmission through increased activation of different pathways. For example, enhanced activation of the TNFα-TNFR1-NF-κB-glutaminase-GAT3 pathway and the TNFα-TNFR1-S1PR2-CCL2-BDNF-TrkB pathway in cerebellum of hyperammonemic rats enhances GABAergic neurotransmission. This is mediated by mechanisms affecting GABA synthesizing enzymes GAD67 and GAD65, total and extracellular GABA levels, membrane expression of GABAA receptor subunits, of GABA transporters GAT1 and GAT three and of chloride co-transporters. Reducing neuroinflammation reverses these changes, normalizes GABAergic neurotransmission and restores motor coordination. There is an interplay between GABAergic neurotransmission and neuroinflammation, which modulate each other and altogether modulate motor coordination and cognitive function. In this way, neuroinflammation may be also reduced by reducing GABAergic neurotransmission, which may also improve cognitive and motor function in pathologies associated to neuroinflammation and enhanced GABAergic neurotransmission such as hyperammonemia, hepatic encephalopathy or Parkinson's disease. This provides therapeutic targets that may be modulated to improve cognitive and motor function and other alterations such as fatigue in a wide range of pathologies. As a proof of concept it has been shown that antagonists of GABAA receptors such as bicuculline reduces neuroinflammation and improves cognitive and motor function impairment in rat models of hyperammonemia and hepatic encephalopathy. Antagonists of GABAA receptors are not ideal therapeutic tools because they can induce secondary effects. As a more effective treatment to reduce GABAergic neurotransmission new compounds modulating it by other mechanisms are being developed. Golexanolone reduces GABAergic neurotransmission by reducing the potentiation of GABAA receptor activation by neurosteroids such as allopregnanolone. Golexanolone reduces neuroinflammation and GABAergic neurotransmission in animal models of hyperammonemia, hepatic encephalopathy and cholestasis and this is associated with improvement of fatigue, cognitive impairment and motor incoordination. This type of compounds may be useful therapeutic tools to improve cognitive and motor function in different pathologies associated with neuroinflammation and increased GABAergic neurotransmission.
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Affiliation(s)
- Marta Llansola
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - Yaiza M. Arenas
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - María Sancho-Alonso
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - Gergana Mincheva
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | | | | | | | - Vicente Felipo
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
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7
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Chen W, Zheng Y, Zhu Y, Liu D, Zhu L. Pharmacokinetics, tissue distribution, and plasma protein binding ratio of bicuculline following intragastric and intravenous administration in rats using ultra-high-performance liquid chromatography-tandem mass spectrometry. Biomed Chromatogr 2024; 38:e5802. [PMID: 38110194 DOI: 10.1002/bmc.5802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 11/08/2023] [Accepted: 11/16/2023] [Indexed: 12/20/2023]
Abstract
Bicuculline is a natural isoquinoline alkaloid that works as a gamma-aminobutyric acid receptor antagonist. It is widely found in Papaveraceae plants used in traditional Chinese medicines. Bicuculline not only has been shown to have favorable analgesic, memory-improving, and anxiolytic effects but may also cause adverse effects such as convulsions and epilepsy. A simple, rapid, and sensitive method was developed and validated for the determination of bicuculline in the plasma and tissue samples in rats by ultra-high-performance liquid chromatography-tandem mass spectrometry (MS/MS). The chromatographic separation was performed on a Thermo Scientific C18 column. The MS/MS system was operated in the positive multiple reaction monitoring mode, and the precursor-product ion transitions were optimized as m/z 368.0 → 307.1 for bicuculline and as 354.1 → 188.1 for protopine (internal standard). The linearity, accuracy, precision, recovery, and matrix effect were within acceptable limits. The experimental data showed that bicuculline was rapidly absorbed and eliminated in rats, with a moderate plasma protein binding ratio and low bioavailability. The main tissues of distribution were the kidney, liver, and brain; bicuculline could exert its pharmacological effects across the blood-brain barrier. This study has positive implications for the clinical use of herbal medicines containing bicuculline and for further development.
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Affiliation(s)
- Weikang Chen
- Jiangxi Institute for Drug Control/Jiangxi Engineering Research Center for Drug and Medical Device Quality, Nanchang, China
- National Medical Products Administration Key Laboratory of Quality Evaluation of Traditional Chinese Patent Medicine, Nanchang, China
| | - Yangbin Zheng
- Jiangxi Institute for Drug Control/Jiangxi Engineering Research Center for Drug and Medical Device Quality, Nanchang, China
- National Medical Products Administration Key Laboratory of Quality Evaluation of Traditional Chinese Patent Medicine, Nanchang, China
| | - Yanyan Zhu
- Jiangxi Institute for Drug Control/Jiangxi Engineering Research Center for Drug and Medical Device Quality, Nanchang, China
- National Medical Products Administration Key Laboratory of Quality Evaluation of Traditional Chinese Patent Medicine, Nanchang, China
- Jiangxi University of Traditional Chinese Medicine, Nanchang, China
| | - Dehong Liu
- Jiangxi Institute for Drug Control/Jiangxi Engineering Research Center for Drug and Medical Device Quality, Nanchang, China
- National Medical Products Administration Key Laboratory of Quality Evaluation of Traditional Chinese Patent Medicine, Nanchang, China
| | - Lianghui Zhu
- Jiangxi Institute for Drug Control/Jiangxi Engineering Research Center for Drug and Medical Device Quality, Nanchang, China
- National Medical Products Administration Key Laboratory of Quality Evaluation of Traditional Chinese Patent Medicine, Nanchang, China
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8
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Sancho-Alonso M, Arenas YM, Izquierdo-Altarejos P, Martinez-Garcia M, Llansola M, Felipo V. Enhanced Activation of the S1PR2-IL-1β-Src-BDNF-TrkB Pathway Mediates Neuroinflammation in the Hippocampus and Cognitive Impairment in Hyperammonemic Rats. Int J Mol Sci 2023; 24:17251. [PMID: 38139078 PMCID: PMC10744193 DOI: 10.3390/ijms242417251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 12/04/2023] [Accepted: 12/06/2023] [Indexed: 12/24/2023] Open
Abstract
Hyperammonemia contributes to hepatic encephalopathy. In hyperammonemic rats, cognitive function is impaired by altered glutamatergic neurotransmission induced by neuroinflammation. The underlying mechanisms remain unclear. Enhanced sphingosine-1-phosphate receptor 2 (S1PR2) activation in the cerebellum of hyperammonemic rats contributes to neuroinflammation. in In hyperammonemic rats, we assessed if blocking S1PR2 reduced hippocampal neuroinflammation and reversed cognitive impairment and if the signaling pathways were involved. S1PR2 was blocked with intracerebral JTE-013, and cognitive function was evaluated. The signaling pathways inducing neuroinflammation and altered glutamate receptors were analyzed in hippocampal slices. JTE-013 improved cognitive function in the hyperammonemic rats, and hyperammonemia increased S1P. This increased IL-1β, which enhanced Src activity, increased CCL2, activated microglia and increased the membrane expression of the NMDA receptor subunit GLUN2B. This increased p38-MAPK activity, which altered the membrane expression of AMPA receptor subunits and increased BDNF, which activated the TrkB → PI3K → Akt → CREB pathway, inducing sustained neuroinflammation. This report unveils key pathways involved in the induction and maintenance of neuroinflammation in the hippocampus of hyperammonemic rats and supports S1PR2 as a therapeutic target for cognitive impairment.
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Affiliation(s)
- María Sancho-Alonso
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain; (M.S.-A.); (Y.M.A.); (P.I.-A.); (M.M.-G.); (V.F.)
- Institute of Biomedical Research of Barcelona (IIBB), Spanish National Research Council (CSIC), 08036 Barcelona, Spain
- Systems Neuropharmacology Research Group, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain
- Biomedical Research Networking Center for Mental Health (CIBERSAM), Institute of Health Carlos III (ISCIII), 28029 Madrid, Spain
| | - Yaiza M. Arenas
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain; (M.S.-A.); (Y.M.A.); (P.I.-A.); (M.M.-G.); (V.F.)
| | - Paula Izquierdo-Altarejos
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain; (M.S.-A.); (Y.M.A.); (P.I.-A.); (M.M.-G.); (V.F.)
| | - Mar Martinez-Garcia
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain; (M.S.-A.); (Y.M.A.); (P.I.-A.); (M.M.-G.); (V.F.)
| | - Marta Llansola
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain; (M.S.-A.); (Y.M.A.); (P.I.-A.); (M.M.-G.); (V.F.)
| | - Vicente Felipo
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain; (M.S.-A.); (Y.M.A.); (P.I.-A.); (M.M.-G.); (V.F.)
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Santos RPC, Toscano ECDB, Rachid MA. Anti-inflammatory strategies for hepatic encephalopathy: preclinical studies. ARQUIVOS DE NEURO-PSIQUIATRIA 2023. [PMID: 37487550 PMCID: PMC10371400 DOI: 10.1055/s-0043-1767819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/26/2023]
Abstract
Hepatic encephalopathy (HE) is a potentially reversible neuropsychiatric syndrome. Often, HE causes cognitive and motor dysfunctions due to an acute or chronic insufficiency of the liver or a shunting between the hepatic portal vein and systemic vasculature. Liver damage induces peripheral changes, such as in the metabolism and peripheral inflammatory responses that trigger exacerbated neuroinflammation. In experimental models, anti-inflammatory strategies have demonstrated neuroprotective effects, leading to a reduction in HE-related cognitive and motor impairments. In this scenario, a growing body of evidence has shown that peripheral and central nervous system inflammation are promising preclinical targets. In this review, we performed an overview of FDA-approved drugs and natural compounds which are used in the treatment of other neurological and nonneurological diseases that have played a neuroprotective role in experimental HE, at least in part, through anti-inflammatory mechanisms. Despite the exciting results from animal models, the available data should be critically interpreted, highlighting the importance of translating the findings for clinical essays.
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Affiliation(s)
- Rafaela Pinto Coelho Santos
- Universidade Federal de Minas Gerais, Instituto de Ciências Biológicas, Departamento de Patologia Geral, Laboratório de Patologia Celular e Molecular, Belo Horizonte MG, Brazil
| | - Eliana Cristina de Brito Toscano
- Universidade Federal de Juiz de Fora, Faculdade de Medicina, Departamento de Patologia, Laboratório Integrado de Pesquisa em Patologia, Juiz de Fora MG, Brazil
- Universidade Federal de Juiz e Fora, Faculdade de Medicina, Programa de Pós-Graduação em Saúde, Juiz de Fora MG, Brazil
| | - Milene Alvarenga Rachid
- Universidade Federal de Minas Gerais, Instituto de Ciências Biológicas, Departamento de Patologia Geral, Laboratório de Patologia Celular e Molecular, Belo Horizonte MG, Brazil
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Balzano T, Llansola M, Arenas YM, Izquierdo-Altarejos P, Felipo V. Hepatic encephalopathy: investigational drugs in preclinical and early phase development. Expert Opin Investig Drugs 2023; 32:1055-1069. [PMID: 37902074 DOI: 10.1080/13543784.2023.2277386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 10/26/2023] [Indexed: 10/31/2023]
Abstract
INTRODUCTION Hepatic encephalopathy (HE) is a neuropsychiatric syndrome, in patients with liver disease, which affects life quality and span. Current treatments are lactulose or rifaximin, acting on gut microbiota. Treatments aiming ammonia levels reduction have been tested with little success. AREAS COVERED Pre-clinical research shows that the process inducing HE involves sequentially: liver failure, altered microbiome, hyperammonemia, peripheral inflammation, changes in immunophenotype and extracellular vesicles and neuroinflammation, which alters neurotransmission impairing cognitive and motor function. HE may be reversed using drugs acting at any step: modulating microbiota with probiotics or fecal transplantation; reducing peripheral inflammation with anti-TNFα, autotaxin inhibitors or silymarin; reducing neuroinflammation with sulforaphane, p38 MAP kinase or phosphodiesteras 5 inhibitors, antagonists of sphingosine-1-phosphate receptor 2, enhancing meningeal lymphatic drainage or with extracellular vesicles from mesenchymal stem cells; reducing GABAergic neurotransmission with indomethacin or golexanolone. EXPERT OPINION A factor limiting the progress of HE treatment is the lack of translation of research advances into clinical trials. Only drugs acting on microbiota or ammonia reduction have been tested in patients. It is urgent to change the mentality on how to approach HE treatment to develop clinical trials to assess drugs acting on the immune system/peripheral inflammation, neuroinflammation or neurotransmission to improve HE.
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Affiliation(s)
- Tiziano Balzano
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
- HM CINAC (Centro Integral de Neurociencias Abarca Campal), Hospital Universitario HM Puerta del Sur, HM Hospitales, Madrid, Spain
| | - Marta Llansola
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - Yaiza M Arenas
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
- Departamento de Patología, Facultad de Medicina, Universidad Valencia, Valencia, Spain
| | | | - Vicente Felipo
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
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Du Y, Li J, Wang M, Tian Q, Pang Y, Wen Y, Wu D, Wang YT, Dong Z. Genetic inhibition of glutamate allosteric potentiation of GABA ARs in mice results in hyperexcitability, leading to neurobehavioral abnormalities. MedComm (Beijing) 2023; 4:e235. [PMID: 37101797 PMCID: PMC10123808 DOI: 10.1002/mco2.235] [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: 10/19/2022] [Revised: 02/15/2023] [Accepted: 02/16/2023] [Indexed: 04/28/2023] Open
Abstract
The imbalance between neuronal excitation and inhibition (E/I) in neural circuit has been considered to be at the root of numerous brain disorders. We recently reported a novel feedback crosstalk between the excitatory neurotransmitter glutamate and inhibitory γ-aminobutyric acid type A receptor (GABAAR)-glutamate allosteric potentiation of GABAAR functions through a direct binding of glutamate to the GABAAR itself. Here, we investigated the physiological significance and pathological implications of this cross-talk by generating the β3E182G knock-in (KI) mice. We found that β3E182G KI, while had little effect on basal GABAAR-mediated synaptic transmission, significantly reduced glutamate potentiation of GABAAR-mediated responses. These KI mice displayed lower thresholds for noxious stimuli, higher susceptibility to seizures and enhanced hippocampus-related learning and memory. Additionally, the KI mice exhibited impaired social interactions and decreased anxiety-like behaviors. Importantly, hippocampal overexpression of wild-type β3-containing GABAARs was sufficient to rescue the deficits of glutamate potentiation of GABAAR-mediated responses, hippocampus-related behavioral abnormalities of increased epileptic susceptibility, and impaired social interactions. Our data indicate that the novel crosstalk among excitatory glutamate and inhibitory GABAAR functions as a homeostatic mechanism in fine-tuning neuronal E/I balance, thereby playing an essential role in ensuring normal brain functioning.
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Affiliation(s)
- Yehong Du
- Growth, Development, and Mental Health of Children and Adolescence CenterPediatric Research InstituteMinistry of Education Key Laboratory of Child Development and DisordersNational Clinical Research Center for Child Health and DisordersChina International Science and Technology Cooperation Base of Child Development and Critical DisordersChongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory DisordersChildren's Hospital of Chongqing Medical UniversityChongqingChina
| | - Junjie Li
- Growth, Development, and Mental Health of Children and Adolescence CenterPediatric Research InstituteMinistry of Education Key Laboratory of Child Development and DisordersNational Clinical Research Center for Child Health and DisordersChina International Science and Technology Cooperation Base of Child Development and Critical DisordersChongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory DisordersChildren's Hospital of Chongqing Medical UniversityChongqingChina
| | - Maoju Wang
- Growth, Development, and Mental Health of Children and Adolescence CenterPediatric Research InstituteMinistry of Education Key Laboratory of Child Development and DisordersNational Clinical Research Center for Child Health and DisordersChina International Science and Technology Cooperation Base of Child Development and Critical DisordersChongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory DisordersChildren's Hospital of Chongqing Medical UniversityChongqingChina
| | - Qiuyun Tian
- Growth, Development, and Mental Health of Children and Adolescence CenterPediatric Research InstituteMinistry of Education Key Laboratory of Child Development and DisordersNational Clinical Research Center for Child Health and DisordersChina International Science and Technology Cooperation Base of Child Development and Critical DisordersChongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory DisordersChildren's Hospital of Chongqing Medical UniversityChongqingChina
| | - Yayan Pang
- Growth, Development, and Mental Health of Children and Adolescence CenterPediatric Research InstituteMinistry of Education Key Laboratory of Child Development and DisordersNational Clinical Research Center for Child Health and DisordersChina International Science and Technology Cooperation Base of Child Development and Critical DisordersChongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory DisordersChildren's Hospital of Chongqing Medical UniversityChongqingChina
| | - Ya Wen
- Brain Research Centre and Department of MedicineVancouver Coastal Health Research InstituteUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Dongchuan Wu
- Translational Medicine Research CenterChina Medical University HospitalGraduate Institutes of Biomedical SciencesTaichungChina
| | - Yu Tian Wang
- Brain Research Centre and Department of MedicineVancouver Coastal Health Research InstituteUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Zhifang Dong
- Growth, Development, and Mental Health of Children and Adolescence CenterPediatric Research InstituteMinistry of Education Key Laboratory of Child Development and DisordersNational Clinical Research Center for Child Health and DisordersChina International Science and Technology Cooperation Base of Child Development and Critical DisordersChongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory DisordersChildren's Hospital of Chongqing Medical UniversityChongqingChina
- Institute for Brain Science and Disease of Chongqing Medical UniversityChongqingChina
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12
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Izquierdo-Altarejos P, Cabrera-Pastor A, Martínez-García M, Sánchez-Huertas C, Hernández A, Moreno-Manzano V, Felipo V. Extracellular vesicles from mesenchymal stem cells reduce neuroinflammation in hippocampus and restore cognitive function in hyperammonemic rats. J Neuroinflammation 2023; 20:1. [PMID: 36593485 PMCID: PMC9806918 DOI: 10.1186/s12974-022-02688-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 12/25/2022] [Indexed: 01/03/2023] Open
Abstract
Chronic hyperammonemia, a main contributor to hepatic encephalopathy (HE), leads to neuroinflammation which alters neurotransmission leading to cognitive impairment. There are no specific treatments for the neurological alterations in HE. Extracellular vesicles (EVs) from mesenchymal stem cells (MSCs) reduce neuroinflammation in some pathological conditions. The aims were to assess if treatment of hyperammonemic rats with EVs from MSCs restores cognitive function and analyze the underlying mechanisms. EVs injected in vivo reach the hippocampus and restore performance of hyperammonemic rats in object location, object recognition, short-term memory in the Y-maze and reference memory in the radial maze. Hyperammonemic rats show reduced TGFβ levels and membrane expression of TGFβ receptors in hippocampus. This leads to microglia activation and reduced Smad7-IkB pathway, which induces NF-κB nuclear translocation in neurons, increasing IL-1β which alters AMPA and NMDA receptors membrane expression, leading to cognitive impairment. These effects are reversed by TGFβ in the EVs from MSCs, which activates TGFβ receptors, reducing microglia activation and NF-κB nuclear translocation in neurons by normalizing the Smad7-IkB pathway. This normalizes IL-1β, AMPA and NMDA receptors membrane expression and, therefore, cognitive function. EVs from MSCs may be useful to improve cognitive function in patients with hyperammonemia and minimal HE.
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Affiliation(s)
- Paula Izquierdo-Altarejos
- grid.418274.c0000 0004 0399 600XLaboratory of Neurobiology, Centro Investigación Príncipe Felipe, Eduardo Primo-Yufera 3, 46012 Valencia, Spain
| | - Andrea Cabrera-Pastor
- grid.418274.c0000 0004 0399 600XLaboratory of Neurobiology, Centro Investigación Príncipe Felipe, Eduardo Primo-Yufera 3, 46012 Valencia, Spain ,grid.476458.c0000 0004 0427 8560Fundación Investigación Hospital Clínico, Instituto de Investigación Sanitaria, INCLIVA, Valencia, Spain
| | - Mar Martínez-García
- grid.418274.c0000 0004 0399 600XLaboratory of Neurobiology, Centro Investigación Príncipe Felipe, Eduardo Primo-Yufera 3, 46012 Valencia, Spain
| | - Carlos Sánchez-Huertas
- grid.418274.c0000 0004 0399 600XNeuronal and Tissue Regeneration Laboratory, Centro Investigación Príncipe Felipe, Valencia, Spain ,grid.466805.90000 0004 1759 6875Laboratory of Bilateral Neural Circuits, Instituto de Neurociencias (CSIC-UMH), Alicante, Spain
| | - Alberto Hernández
- grid.418274.c0000 0004 0399 600XOptical and Confocal Microscopy Service, Centro Investigación Príncipe Felipe, Valencia, Spain
| | - Victoria Moreno-Manzano
- grid.418274.c0000 0004 0399 600XNeuronal and Tissue Regeneration Laboratory, Centro Investigación Príncipe Felipe, Valencia, Spain
| | - Vicente Felipo
- grid.418274.c0000 0004 0399 600XLaboratory of Neurobiology, Centro Investigación Príncipe Felipe, Eduardo Primo-Yufera 3, 46012 Valencia, Spain
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13
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Mincheva G, Gimenez-Garzo C, Izquierdo-Altarejos P, Martinez-Garcia M, Doverskog M, Blackburn TP, Hällgren A, Bäckström T, Llansola M, Felipo V. Golexanolone, a GABA A receptor modulating steroid antagonist, restores motor coordination and cognitive function in hyperammonemic rats by dual effects on peripheral inflammation and neuroinflammation. CNS Neurosci Ther 2022; 28:1861-1874. [PMID: 35880480 PMCID: PMC9532914 DOI: 10.1111/cns.13926] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 07/08/2022] [Accepted: 07/09/2022] [Indexed: 11/29/2022] Open
Abstract
Aims Hyperammonemic rats show peripheral inflammation, increased GABAergic neurotransmission and neuroinflammation in cerebellum and hippocampus which induce motor incoordination and cognitive impairment. Neuroinflammation enhances GABAergic neurotransmission in cerebellum by enhancing the TNFR1‐glutaminase‐GAT3 and TNFR1‐CCL2‐TrkB‐KCC2 pathways. Golexanolone reduces GABAA receptors potentiation by allopregnanolone. This work aimed to assess if treatment of hyperammonemic rats with golexanolone reduces peripheral inflammation and neuroinflammation and restores cognitive and motor function and to analyze underlying mechanisms. Methods Rats were treated with golexanolone and effects on peripheral inflammation, neuroinflammation, TNFR1‐glutaminase‐GAT3 and TNFR1‐CCL2‐TrkB‐KCC2 pathways, and cognitive and motor function were analyzed. Results Hyperammonemic rats show increased TNFα and reduced IL‐10 in plasma, microglia and astrocytes activation in cerebellum and hippocampus, and impaired motor coordination and spatial and short‐term memories. Treating hyperammonemic rats with golexanolone reversed changes in peripheral inflammation, microglia and astrocytes activation and restored motor coordination and spatial and short‐term memory. This was associated with reversal of the hyperammonemia‐enhanced activation in cerebellum of the TNFR1‐glutaminase‐GAT3 and TNFR1‐CCL2‐TrkB‐KCC2 pathways. Conclusion Reducing GABAA receptors activation with golexanolone reduces peripheral inflammation and neuroinflammation and improves cognitive and motor function in hyperammonemic rats. The effects identified would also occur in patients with hepatic encephalopathy and, likely, in other pathologies associated with neuroinflammation.
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Affiliation(s)
- Gergana Mincheva
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - Carla Gimenez-Garzo
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | | | - Mar Martinez-Garcia
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | | | | | | | - Torbjörn Bäckström
- Umecrine Cognition AB, Solna, Sweden.,Umeå Neurosteroid Research Center, Clinical Sciences at Umeå University, Umeå, Sweden
| | - Marta Llansola
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - Vicente Felipo
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
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14
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Liu J, Feng X, Wang Y, Xia X, Zheng JC. Astrocytes: GABAceptive and GABAergic Cells in the Brain. Front Cell Neurosci 2022; 16:892497. [PMID: 35755777 PMCID: PMC9231434 DOI: 10.3389/fncel.2022.892497] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 05/17/2022] [Indexed: 12/14/2022] Open
Abstract
Astrocytes, the most numerous glial cells in the brain, play an important role in preserving normal neural functions and mediating the pathogenesis of neurological disorders. Recent studies have shown that astrocytes are GABAceptive and GABAergic astrocytes express GABAA receptors, GABAB receptors, and GABA transporter proteins to capture and internalize GABA. GABAceptive astrocytes thus influence both inhibitory and excitatory neurotransmission by controlling the levels of extracellular GABA. Furthermore, astrocytes synthesize and release GABA to directly regulate brain functions. In this review, we highlight recent research progresses that support astrocytes as GABAceptive and GABAergic cells. We also summarize the roles of GABAceptive and GABAergic astrocytes that serve as an inhibitory node in the intercellular communication in the brain. Besides, we discuss future directions for further expanding our knowledge on the GABAceptive and GABAergic astrocyte signaling.
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Affiliation(s)
- Jianhui Liu
- Department of Anesthesiology, Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai, China
| | - Xuanran Feng
- Department of Anesthesiology, Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai, China
| | - Yi Wang
- Translational Research Center, Shanghai Yangzhi Rehabilitation Hospital affiliated to Tongji University School of Medicine, Shanghai, China
| | - Xiaohuan Xia
- Department of Anesthesiology, Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai, China.,Center for Translational Neurodegeneration and Regenerative Therapy, Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai, China.,Shanghai Frontiers Science Center of Nanocatalytic Medicine, Shanghai, China.,Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People's Hospital affiliated to Tongji University School of Medicine, Shanghai, China
| | - Jialin C Zheng
- Department of Anesthesiology, Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai, China.,Center for Translational Neurodegeneration and Regenerative Therapy, Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai, China.,Shanghai Frontiers Science Center of Nanocatalytic Medicine, Shanghai, China.,Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People's Hospital affiliated to Tongji University School of Medicine, Shanghai, China.,Collaborative Innovation Center for Brain Science, Tongji University, Shanghai, China
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15
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Hyperammonemia Enhances GABAergic Neurotransmission in Hippocampus: Underlying Mechanisms and Modulation by Extracellular cGMP. Mol Neurobiol 2022; 59:3431-3448. [PMID: 35320456 DOI: 10.1007/s12035-022-02803-9] [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: 01/11/2022] [Accepted: 03/16/2022] [Indexed: 10/18/2022]
Abstract
Rats with chronic hyperammonemia reproduce the cognitive and motor impairment present in patients with hepatic encephalopathy. It has been proposed that enhanced GABAergic neurotransmission in hippocampus may contribute to impaired learning and memory in hyperammonemic rats. However, there are no direct evidences of the effects of hyperammonemia on GABAergic neurotransmission in hippocampus or on the underlying mechanisms. The aims of this work were to assess if chronic hyperammonemia enhances the function of GABAA receptors in hippocampus and to identify the underlying mechanisms. Activation of GABAA receptors is enhanced in hippocampus of hyperammonemic rats, as analyzed in a multielectrode array system. Hyperammonemia reduces membrane expression of the GABA transporters GAT1 and GAT3, which is associated with increased extracellular GABA concentration. Hyperammonemia also increases gephyrin levels and phosphorylation of the β3 subunit of GABAA receptor, which are associated with increased membrane expression of the GABAA receptor subunits α1, α2, γ2, β3, and δ. Enhanced levels of extracellular GABA and increased membrane expression of GABAA receptors would be responsible for the enhanced GABAergic neurotransmission in hippocampus of hyperammonemic rats. Increasing extracellular cGMP reverses the increase in GABAA receptors activation by normalizing the membrane expression of GABA transporters and GABAA receptors. The increased GABAergic neurotransmission in hippocampus would contribute to cognitive impairment in hyperammonemic rats. The results reported suggest that reducing GABAergic tone in hippocampus by increasing extracellular cGMP or by other means may be useful to improve cognitive function in hyperammonemia and in cirrhotic patients with minimal or clinical hepatic encephalopathy.
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16
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Sánchez-Hernández J, Aguilera P, Manjarrez-Marmolejo J, Franco-Pérez J. Fructose ingestion modifies NMDA receptors and exacerbates the seizures induced by kainic acid. Neurosci Lett 2022; 772:136476. [DOI: 10.1016/j.neulet.2022.136476] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 12/17/2021] [Accepted: 01/20/2022] [Indexed: 12/24/2022]
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17
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Balzano T, Leone P, Ivaylova G, Castro MC, Reyes L, Ramón C, Malaguarnera M, Llansola M, Felipo V. Rifaximin Prevents T-Lymphocytes and Macrophages Infiltration in Cerebellum and Restores Motor Incoordination in Rats with Mild Liver Damage. Biomedicines 2021; 9:biomedicines9081002. [PMID: 34440206 PMCID: PMC8393984 DOI: 10.3390/biomedicines9081002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 08/02/2021] [Accepted: 08/03/2021] [Indexed: 12/30/2022] Open
Abstract
In patients with liver cirrhosis, minimal hepatic encephalopathy (MHE) is triggered by a shift in peripheral inflammation, promoting lymphocyte infiltration into the brain. Rifaximin improves neurological function in MHE by normalizing peripheral inflammation. Patients who died with steatohepatitis showed T-lymphocyte infiltration and neuroinflammation in the cerebellum, suggesting that MHE may already occur in these patients. The aims of this work were to assess, in a rat model of mild liver damage similar to steatohepatitis, whether: (1) the rats show impaired motor coordination in the early phases of liver damage; (2) this is associated with changes in the immune system and infiltration of immune cells into the brain; and (3) rifaximin improves motor incoordination, associated with improved peripheral inflammation, reduced infiltration of immune cells and neuroinflammation in the cerebellum, and restoration of the alterations in neurotransmission. Liver damage was induced by carbon tetrachloride (CCl4) injection over four weeks. Peripheral inflammation, immune cell infiltration, neuroinflammation, and neurotransmission in the cerebellum and motor coordination were assessed. Mild liver damage induces neuroinflammation and altered neurotransmission in the cerebellum and motor incoordination. These alterations are associated with increased TNFa, CCL20, and CX3CL1 in plasma and cerebellum, IL-17 and IL-15 in plasma, and CCL2 in cerebellum. This promotes T-lymphocyte and macrophage infiltration in the cerebellum. Early treatment with rifaximin prevents the shift in peripheral inflammation, immune cell infiltration, neuroinflammation, and motor incoordination. This report provides new clues regarding the mechanisms of the beneficial effects of rifaximin, suggesting that early rifaximin treatment could prevent neurological impairment in patients with steatohepatitis.
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18
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Hamdani EH, Popek M, Frontczak-Baniewicz M, Utheim TP, Albrecht J, Zielińska M, Chaudhry FA. Perturbation of astroglial Slc38 glutamine transporters by NH 4 + contributes to neurophysiologic manifestations in acute liver failure. FASEB J 2021; 35:e21588. [PMID: 34169573 DOI: 10.1096/fj.202001712rr] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 03/17/2021] [Accepted: 03/25/2021] [Indexed: 02/07/2023]
Abstract
Ammonia is considered the main pathogenic toxin in hepatic encephalopathy (HE). However, the molecular mechanisms involved have been disputed. As altered glutamatergic and GABAergic neurotransmission has been reported in HE, we investigated whether four members of the solute carrier 38 (Slc38) family of amino acid transporters-involved in the replenishment of glutamate and GABA-contribute to ammonia neurotoxicity in HE. We show that ammonium ion exerts multiple actions on the Slc38 transporters: It competes with glutamine for the binding to the system N transporters Slc38a3 and Slc38a5, consequently inhibiting bidirectional astroglial glutamine transport. It also competes with H+ , Na+ , and K+ for uncoupled permeation through the same transporters, which may perturb astroglial intracellular pH, membrane potential, and K+ -buffering. Knockdown of Slc38a3 in mice results in cerebral cortical edema and disrupted neurotransmitter synthesis mimicking events contributing to HE development. Finally, in a mouse model of acute liver failure (ALF), we demonstrate the downregulation of Slc38a3 protein, impeded astroglial glutamine release, and cytotoxic edema. Altogether, we demonstrate contribution of Slc38 transporters to the ammonia-induced impairment of glutamine recycling between astrocytes and neurons, a phenomenon underlying acute ammonia neurotoxicity in the setting of ALF.
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Affiliation(s)
- El Hassan Hamdani
- Department of Molecular Medicine, University of Oslo (UiO), Oslo, Norway.,Institute of Behavioural Science, Oslo Metropolitan University, Oslo, Norway
| | - Mariusz Popek
- Neurotoxicology Department, Mossakowski Medical Research Institute PAS, Warsaw, Poland
| | | | - Tor Paaske Utheim
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway.,Department of Plastic and Reconstructive Surgery, Oslo University Hospital, Oslo, Norway
| | - Jan Albrecht
- Neurotoxicology Department, Mossakowski Medical Research Institute PAS, Warsaw, Poland
| | - Magdalena Zielińska
- Neurotoxicology Department, Mossakowski Medical Research Institute PAS, Warsaw, Poland
| | - Farrukh Abbas Chaudhry
- Department of Molecular Medicine, University of Oslo (UiO), Oslo, Norway.,Department of Plastic and Reconstructive Surgery, Oslo University Hospital, Oslo, Norway
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19
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Zhang Y, Tan SL, Du J, Chen Y, Jia J, Feng JG, Liu KX, Zhou J. Dexmedetomidine alleviates neuroinflammation, restores sleep disorders and neurobehavioral abnormalities in rats with minimal hepatic encephalopathy. Int Immunopharmacol 2021; 96:107795. [PMID: 34162157 DOI: 10.1016/j.intimp.2021.107795] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 05/05/2021] [Accepted: 05/16/2021] [Indexed: 10/21/2022]
Abstract
The occurrence and progress of minimal hepatic encephalopathy (MHE) is closely related to the inflammatory response; however, inflammation contributes to behavioral abnormalities and sleep disorders. Dexmedetomidine has anti-inflammatory effects against various diseases. Whether dexmedetomidine improves MHE and the underlying mechanism is yet unclear. The present study aimed to explore the effects of dexmedetomidine on sleep structure, neurobehavior, and brain morphology of MHE rats and investigate its underlying mechanism. A rat MHE model was established by intraperitoneal injection of thioacetamide (TAA). Dexmedetomidine or yohimbine was administered intraperitoneally to investigate the role of α2 adrenoreceptor in the protection conferred by dexmedetomidine. The 24-h sleep, neurobehavioral changes, the liver function, blood ammonia and morphological changes of the liver and brain were assessed. Also, the microglia, astrocytes, neurons, the expression of pro-inflammatory factors (IL-1β, TNF-α, IL-18), and NLRP3 inflammasomes were detected. The results showed that marked sleep disorders, cognitive impairment, anxiety, abnormal liver function and pathological damage of liver and brain were detected in the MHE rats. The microglia in the prefrontal cortex was highly activated along with the increased expression of pro-inflammatory factors and NLRP3 inflammasomes. Interestingly, dexmedetomidine improved above indicators, however, yohimbine significantly abolished the protection of dexmedetomidine. These findings showed that dexmedetomidine restored the changes in the sleep disorders and neurobehavior in rats and reduced brain damage. The mechanism might be partially related to the activation of α2 adrenergic receptors, reduction of neuroinflammatory response, and inhibition of the activation of microglia and NLRP3/Caspase1 signaling pathway.
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Affiliation(s)
- Yu Zhang
- Department of Anesthesiology, The Affiliated Hospital of Southwest Medical University, Luzhou, PR China
| | - Su-Lan Tan
- Department of Anesthesiology, The Affiliated Hospital of Southwest Medical University, Luzhou, PR China
| | - Juan Du
- Department of Anesthesiology, The Affiliated Hospital of Southwest Medical University, Luzhou, PR China
| | - Ye Chen
- Department of Traditional Chinese Medicine, The Affiliated Hospital of Southwest Medical University, Luzhou, PR China
| | - Jing Jia
- Department of Anesthesiology, The Affiliated Hospital of Southwest Medical University, Luzhou, PR China
| | - Jian-Guo Feng
- Department of Anesthesiology, The Affiliated Hospital of Southwest Medical University, Luzhou, PR China
| | - Ke-Xuan Liu
- Department of Anesthesiology, Nanfang Hospital, Southern Medical University, Guangzhou, PR China
| | - Jun Zhou
- Department of Anesthesiology, The Affiliated Hospital of Southwest Medical University, Luzhou, PR China.
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20
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The Dual Role of the GABA A Receptor in Peripheral Inflammation and Neuroinflammation: A Study in Hyperammonemic Rats. Int J Mol Sci 2021; 22:ijms22136772. [PMID: 34202516 PMCID: PMC8268725 DOI: 10.3390/ijms22136772] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/18/2021] [Accepted: 06/21/2021] [Indexed: 12/15/2022] Open
Abstract
Cognitive and motor impairment in minimal hepatic encephalopathy (MHE) are mediated by neuroinflammation, which is induced by hyperammonemia and peripheral inflammation. GABAergic neurotransmission in the cerebellum is altered in rats with chronic hyperammonemia. The mechanisms by which hyperammonemia induces neuroinflammation remain unknown. We hypothesized that GABAA receptors can modulate cerebellar neuroinflammation. The GABAA antagonist bicuculline was administrated daily (i.p.) for four weeks in control and hyperammonemic rats. Its effects on peripheral inflammation and on neuroinflammation as well as glutamate and GABA neurotransmission in the cerebellum were assessed. In hyperammonemic rats, bicuculline decreases IL-6 and TNFα and increases IL-10 in the plasma, reduces astrocyte activation, induces the microglia M2 phenotype, and reduces IL-1β and TNFα in the cerebellum. However, in control rats, bicuculline increases IL-6 and decreases IL-10 plasma levels and induces microglial activation. Bicuculline restores the membrane expression of some glutamate and GABA transporters restoring the extracellular levels of GABA in hyperammonemic rats. Blocking GABAA receptors improves peripheral inflammation and cerebellar neuroinflammation, restoring neurotransmission in hyperammonemic rats, whereas it induces inflammation and neuroinflammation in controls. This suggests a complex interaction between GABAergic and immune systems. The modulation of GABAA receptors could be a suitable target for improving neuroinflammation in MHE.
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21
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Bu J, Huang S, Wang J, Xia T, Liu H, You Y, Wang Z, Liu K. The GABA A Receptor Influences Pressure Overload-Induced Heart Failure by Modulating Macrophages in Mice. Front Immunol 2021; 12:670153. [PMID: 34135897 PMCID: PMC8201502 DOI: 10.3389/fimmu.2021.670153] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 04/20/2021] [Indexed: 12/24/2022] Open
Abstract
Background Myocardial macrophages have key roles in cardiac remodeling and dysfunction. The gamma-aminobutyric acid subtype A (GABAA) receptor was recently found to be distributed in macrophages, allowing regulation of inflammatory responses to various diseases. This study aimed to clarify the role of GABAA receptor-mediated macrophage responses in pressure overload-induced heart failure. Methods and Results C57BL/6J mice underwent transverse aortic constriction for pressure-overload hypertrophy (POH) and were intraperitoneally treated with a specific GABAA receptor agonist (topiramate) or antagonist (bicuculline). Echocardiography, histology, and flow cytometry were performed to evaluate the causes and effects of myocardial hypertrophy and fibrosis. Activation of the GABAA receptor by topiramate reduced ejection fraction and fractional shortening, enlarged the end-diastolic and end-systolic left ventricular internal diameter, aggravated myocardial hypertrophy and fibrosis, and accelerated heart failure in response to pressure overload. Mechanistically, topiramate increased the number of Ly6Clow macrophages in the heart during POH and circulating Ly6Chigh classic monocyte infiltration in late-phase POH. Further, topiramate drove Ly6Clow macrophages toward MHCIIhigh macrophage polarization. As a result, Ly6Clow macrophages activated the amphiregulin-induced AKT/mTOR signaling pathway, and Ly6ClowMHCIIhigh macrophage polarization increased expression levels of osteopontin and TGF-β, which led to myocardial hypertrophy and fibrosis. Conversely, GABAA receptor blockage with bicuculline reversed these effects. Conclusions Control of the GABAA receptor activity in monocytes/macrophages plays an important role in myocardial hypertrophy and fibrosis after POH. Blockade of the GABAA receptor has the potential to improve pressure overload-induced heart failure.
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Affiliation(s)
- Jin Bu
- Department of Pediatrics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shiyuan Huang
- Department of Geriatrics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jue Wang
- Department of Hematology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Tong Xia
- Department of Geriatrics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hui Liu
- Department of Geriatrics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ya You
- Department of Geriatrics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhaohui Wang
- Department of Geriatrics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Kun Liu
- Institution of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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22
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Curcumin prevents cognitive deficits in the bile duct ligated rats. Psychopharmacology (Berl) 2020; 237:3529-3537. [PMID: 32761362 DOI: 10.1007/s00213-020-05633-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Accepted: 07/29/2020] [Indexed: 12/19/2022]
Abstract
RATIONALE Bile duct ligation (BDL) in rodents can cause impaired liver function and cognition deficits. Curcumin has shown a preventive and therapeutic role in memory impairment. OBJECTIVES Therefore, this study aimed to explore the effect of curcumin on the performance of male adult Wistar rats that underwent BDL, a model of hepatic encephalopathy (HE) in the Morris water maze (MWM). METHODS Four weeks after surgery, sham (manipulation of common bile duct without ligation) and BDL rats underwent the MWM test. RESULTS The representative data showed that BDL rats exhibited impairments in spatial learning and reference memory in the MWM compared with the sham rats. Treatment of BDL rats with curcumin (40 mg/kg, i.p., for 4 weeks) prevented these impairments, while it did not affect spatial learning and memory in the sham rats, by itself. Curcumin increased expression levels of the pro-survival B cell lymphoma extra-large (Bcl-xL) gene and two genes involved in mitochondrial function, peroxisome proliferative-activated receptor-γ co-activator 1α (PGC-1α) and mitochondrial transcription factor A (TFAM), in the hippocampus of BDL rats compared with the vehicle-treated sham or BDL rats, while it decreased the pro-apoptotic Bcl-2-associated X protein (Bax) gene expression level. BDL up-regulated Bax and down-regulated TFAM, by itself. Furthermore, curcumin reduced the mRNA level of Bax, while it increased Bcl-2 and TFAM mRNA levels. CONCLUSIONS These findings demonstrate the beneficial effect of curcumin on cognitive function in BDL rats of the HE model. The curcumin effect may be related to mitochondrial function improvement in the HE.
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Ahmadi S, Ghaderi H, Saadati N, Samadi S. Mesoporous silica SBA-15 decreases hyperammonemia and affects the gene expression of mitogen-activated protein kinases in the prefrontal cortex of rats with bile duct ligation. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2020; 23:1293-1300. [PMID: 33149861 PMCID: PMC7585539 DOI: 10.22038/ijbms.2020.44658.10436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVES We aim to examine possible ammonia lowering effects of mesoporous silica SBA-15 in rats after the common bile duct ligation (BDL). We also evaluate the effect of SBA-15 treatments during 28 days of BDL on locomotion and rearing behavior, as well as on the gene expression of Jnk3 and p38alpha (p38α) mitogen-activated protein kinases in the prefrontal cortex (PFC). MATERIALS AND METHODS SBA-15 was prepared with the hydrothermal method from the surfactant P123 and tetraethyl orthosilicate (TEOS), and calcined at 550 ºC. Then, the product was characterized by FT-IR, XRD, SEM, and BJH-BET techniques. Male Wistar rats in sham control and a group with BDL received saline but another group with BDL received SBA-15 during 28 days of BDL. We examined all groups of rats weekly for locomotion and rearing behavior; then on day 28, we sacrificed all rats, collected the blood sample, and finally dissected the PFC from the whole brain. RESULTS The SBA-15 treatments had no effect on locomotion but improved rearing behavior on days 7 and 14 of BDL. Biochemical analysis indicated that the SBA-15 treatments in rats with BDL significantly decreased hyperammonemia. The results also revealed that the SBA-15 treatments in rats with BDL significantly restored the decreased Jnk3 gene expression, and increased the p38α gene expression in the PFC. CONCLUSION We conclude that SBA-15 can be used as an ammonia lowering agent in hepatic encephalopathy; however, its improving effects on locomotion and neuroinflammation, as well as signaling molecules in the brain need more investigations.
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Affiliation(s)
- Shamseddin Ahmadi
- Department of Biological Science, Faculty of Science, University of Kurdistan, Sanandaj, Iran,Corresponding author: Shamseddin Ahmadi. Department of Biological Science, Faculty of Science, University of Kurdistan, Sanandaj, Iran. Tel: +98-87-33660075; Fax: +98-87-33622702;
| | - Halaleh Ghaderi
- Department of Biological Science, Faculty of Science, University of Kurdistan, Sanandaj, Iran
| | - Nazila Saadati
- Department of Biological Science, Faculty of Science, University of Kurdistan, Sanandaj, Iran
| | - Saadi Samadi
- Department of Chemistry, Faculty of Science, University of Kurdistan, Sanandaj, Iran
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Han W, Zhang H, Han Y, Duan Z. Cognition-tracking-based strategies for diagnosis and treatment of minimal hepatic encephalopathy. Metab Brain Dis 2020; 35:869-881. [PMID: 32495311 PMCID: PMC7354280 DOI: 10.1007/s11011-020-00539-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 01/23/2020] [Indexed: 12/11/2022]
Abstract
Minimal hepatic encephalopathy (MHE), which shows mild cognitive impairment, is a subtle complication of cirrhosis that has been shown to affect daily functioning and quality of life. However, until 2014, relevant guidelines do not give much attention to the diagnosis and treatment of MHE, resulting in patients being ignored and denied the benefits of treatment. In this review, we summarize recent cognition-based research about (1) alteration of nerve cells, including astrocytes, microglial cells and neurons, in mild cognitive impairment in MHE; (2) comparison of methods in detecting cognitive impairment in MHE; and (3) comparison of methods for therapy of cognitive impairment in MHE. We hope to provide information about diagnosis and treatment of cognitive impairment in patients with MHE.
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Affiliation(s)
- Weijia Han
- Difficult & Complicated Liver Diseases and Artificial Liver Center, Beijing Youan Hospital, Capital Medical University, Beijing, 100069, China
- Beijing Municipal Key Laboratory of Liver Failure and Artificial Liver Treatment Research, Beijing, China
| | - Huanqian Zhang
- Yidu Central Hospital of Weifang Medical College, Shandong, China
| | - Ying Han
- Department of Immunologic Liver Disease, Beijing YouAn Hospital, Capital Medical University, Beijing, China
| | - Zhongping Duan
- Difficult & Complicated Liver Diseases and Artificial Liver Center, Beijing Youan Hospital, Capital Medical University, Beijing, 100069, China.
- Beijing Municipal Key Laboratory of Liver Failure and Artificial Liver Treatment Research, Beijing, China.
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Abstract
Despite widespread use of lactulose and rifaximin for the treatment of hepatic encephalopathy, this complication of advanced liver disease remains a major burden on the health care system in the United States and continues to predispose to high morbidity and mortality. Several agents have surfaced over recent years with promise to treat hepatic encephalopathy and mitigate the cognitive impairment associated with this disease process. The purpose of this article is to highlight the leading emerging therapies in hepatic encephalopathy as well as their therapeutic targets.
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Ahmadi S, Khaledi S. Anxiety in rats with bile duct ligation is associated with activation of JNK3 mitogen-activated protein kinase in the hippocampus. Metab Brain Dis 2020; 35:579-588. [PMID: 32052257 DOI: 10.1007/s11011-020-00542-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 01/30/2020] [Indexed: 12/11/2022]
Abstract
We examine the anxiety-like behaviors in rats with bile duct ligation (BDL), as well as its relationship with the expression of JNK3 and P38 MAPKs in rat hippocampus. Male Wistar rats undergo either sham operation or BDL as a rat model of cirrhotic HE. The anxiety-like behaviors are determined using a light/dark box test two hours befor the surgery on day 1 and on days 7, 14, 21 and 28 of BDL. The gene and protein expression levels of JNK3 and p38 in the hippocampus were examined respectively with qPCR and western blotting methods on day 28 of BDL. The results revealed that anxiety was increased in the cirrhotic HE model rats during 28 days of BDL. The molecular data indicated that the gene expression of Jnk3 and protein levels of JNK3, as well as phospho-JNK3, significantly increased in the hippocampus of the cirrhotic HE model rats compared to the sham control group. However, the results revealed no significant changes in the gene expression and the protein levels of p38 as well as phospho-p38 in the hippocampus of the cirrhotic HE model rats compared to the sham control group. We conclude that the increases in the expression and activation of JNK3 MAPK in the hippocampus may underlie, at least partly, the anxiety-like behaviors in rats with cirrhotic HE.
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Affiliation(s)
- Shamseddin Ahmadi
- Department of Biological Science, Faculty of Science, University of Kurdistan, P.O. Box 416, Sanandaj, Iran.
| | - Shiler Khaledi
- Department of Biological Science, Faculty of Science, University of Kurdistan, P.O. Box 416, Sanandaj, Iran
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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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