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Milewski K, Orzeł-Gajowik K, Zielińska M. Mitochondrial Changes in Rat Brain Endothelial Cells Associated with Hepatic Encephalopathy: Relation to the Blood-Brain Barrier Dysfunction. Neurochem Res 2024; 49:1489-1504. [PMID: 35917006 PMCID: PMC11106209 DOI: 10.1007/s11064-022-03698-7] [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: 08/31/2021] [Revised: 02/17/2022] [Accepted: 07/14/2022] [Indexed: 12/06/2022]
Abstract
The mechanisms underlying cerebral vascular dysfunction and edema during hepatic encephalopathy (HE) are unclear. Blood-brain barrier (BBB) impairment, resulting from increased vascular permeability, has been reported in acute and chronic HE. Mitochondrial dysfunction is a well-documented result of HE mainly affecting astrocytes, but much less so in the BBB-forming endothelial cells. Here we review literature reports and own experimental data obtained in HE models emphasizing alterations in mitochondrial dynamics and function as a possible contributor to the status of brain endothelial cell mitochondria in HE. Own studies on the expression of the mitochondrial fusion-fission controlling genes rendered HE animal model-dependent effects: increase of mitochondrial fusion controlling genes opa1, mfn1 in cerebral vessels in ammonium acetate-induced hyperammonemia, but a decrease of the two former genes and increase of fis1 in vessels in thioacetamide-induced HE. In endothelial cell line (RBE4) after 24 h ammonia and/or TNFα treatment, conditions mimicking crucial aspects of HE in vivo, we observed altered expression of mitochondrial fission/fusion genes: a decrease of opa1, mfn1, and, increase of the fission related fis1 gene. The effect in vitro was paralleled by the generation of reactive oxygen species, decreased total antioxidant capacity, decreased mitochondrial membrane potential, as well as increased permeability of RBE4 cell monolayer to fluorescein isothiocyanate dextran. Electron microscopy documented enlarged mitochondria in the brain endothelial cells of rats in both in vivo models. Collectively, the here observed alterations of cerebral endothelial mitochondria are indicative of their fission, and decreased potential of endothelial mitochondria are likely to contribute to BBB dysfunction in HE.
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Affiliation(s)
- Krzysztof Milewski
- Department of Neurotoxicology, Mossakowski Medical Research Institute, Polish Academy of Sciences, Pawińskiego St. 5, 02-106, Warsaw, Poland.
| | - Karolina Orzeł-Gajowik
- Department of Neurotoxicology, Mossakowski Medical Research Institute, Polish Academy of Sciences, Pawińskiego St. 5, 02-106, Warsaw, Poland
| | - Magdalena Zielińska
- Department of Neurotoxicology, Mossakowski Medical Research Institute, Polish Academy of Sciences, Pawińskiego St. 5, 02-106, Warsaw, Poland.
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2
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Niknahad H, Mobasheri A, Arjmand A, Rafiei E, Alidaee S, Razavi H, Bagheri S, Rezaei H, Sabouri S, Najibi A, Khodaei F, Kashani SMA, Ommati MM, Heidari R. Hepatic encephalopathy complications are diminished by piracetam via the interaction between mitochondrial function, oxidative stress, inflammatory response, and locomotor activity. Heliyon 2023; 9:e20557. [PMID: 37810869 PMCID: PMC10551565 DOI: 10.1016/j.heliyon.2023.e20557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 09/01/2023] [Accepted: 09/28/2023] [Indexed: 10/10/2023] Open
Abstract
Background of the study: Hepatic encephalopathy (HE) is a complication in which brain ammonia (NH4+) levels reach critically high concentrations because of liver failure. HE could lead to a range of neurological complications from locomotor and behavioral disturbances to coma. Several tactics have been established for subsiding blood and brain NH4+. However, there is no precise intervention to mitigate the direct neurological complications of NH4+. Purpose It has been found that oxidative stress, mitochondrial damage, and neuro-inflammation play a fundamental role in NH4+ neurotoxicity. Piracetam is a drug used clinically in neurological complications such as stroke and head trauma. Piracetam could significantly diminish oxidative stress and improve brain mitochondrial function. Research methods In the current study, piracetam (100 and 500 mg/kg, oral) was used in a mice model of HE induced by thioacetamide (TA, 800 mg/kg, single dose, i.p). Results Significant disturbances in animals' locomotor activity, along with increased oxidative stress biomarkers, including reactive oxygen species formation, protein carbonylation, lipid peroxidation, depleted tissue glutathione, and decreased antioxidant capacity, were evident in the brain of TA-treated mice. Meanwhile, mitochondrial permeabilization, mitochondrial depolarization, suppression of dehydrogenases activity, and decreased ATP levels were found in the brain of the TA group. The level of pro-inflammatory cytokines was also significantly high in the brain of HE animals. Conclusion It was found that piracetam significantly enhanced mice's locomotor activity, blunted oxidative stress biomarkers, decreased inflammatory cytokines, and improved mitochondrial indices in hyperammonemic mice. These data suggest piracetam as a neuroprotective agent which could be repurposed for the management of HE.
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Affiliation(s)
- Hossein Niknahad
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Pharmacology and Toxicology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Ali Mobasheri
- Research Unit of Medical Imaging, Physics, And Technology, Faculty of Medicine, University of Oulu, FI-90014, Oulu, Finland
- University Medical Center Utrecht, Departments of Orthopedics Rheumatology and Clinical Immunology, 3508, GA, Utrecht, the Netherlands
- Department of Regenerative Medicine, State Research Institute Centre for Innovative Medicine, LT-08406, Vilnius, Lithuania
| | - Abdollah Arjmand
- Department of Toxicology and Pharmacology, Faculty of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Elahe Rafiei
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Sepideh Alidaee
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Hadi Razavi
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Pharmacology and Toxicology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Sara Bagheri
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Heresh Rezaei
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Pharmacology and Toxicology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Samira Sabouri
- Shanxi Key Laboratory of Ecological, Animal Sciences, And Environmental Veterinary Medicine, College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi, 030801, China
| | - Asma Najibi
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Pharmacology and Toxicology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Forouzan Khodaei
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Seyyed Mohammad Amin Kashani
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Pharmacology and Toxicology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammad Mehdi Ommati
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Shanxi Key Laboratory of Ecological, Animal Sciences, And Environmental Veterinary Medicine, College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi, 030801, China
- Henan Key Laboratory of Environmental and Animal Product Safety, College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471000, Henan, China
| | - Reza Heidari
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
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Montagud-Romero S, Miñarro J, Rodríguez-Arias M. Unravelling the Neuroinflammatory Mechanisms Underlying the Effects of Social Defeat Stress on Use of Drugs of Abuse. Curr Top Behav Neurosci 2021; 54:153-180. [PMID: 34628585 DOI: 10.1007/7854_2021_260] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The immune system provides the first line of the organism's defenses, working to maintain homeostasis against external threats and respond also to internal danger signals. There is much evidence to suggest that modifications of inflammatory parameters are related to vulnerability to develop mental illnesses, such as depression, autism, schizophrenia, and substance use disorders. In addition, not only are inflammatory parameters related to these disorders, but stress also induces the activation of the immune system, as recent preclinical research demonstrates. Social stress activates the immune response in the central nervous system through a number of mechanisms; for example, by promoting microglial stimulation, modifying peripheral and brain cytokine levels, and altering the blood brain barrier, which allows monocytes to traffic into the brain. In this chapter, we will first deal with the most important short- and long-term consequences of social defeat (SD) stress on the neuroinflammatory response. SD experiences (brief episodes of social confrontations during adolescence and adulthood) induce functional modifications in the brain, which are accompanied by an increase in proinflammatory markers. Most importantly, inflammatory mechanisms play a significant role in mediating the process of adaptation in the face of adversity (resilience vs susceptibility), allowing us to understand individual differences in stress responses. Secondly, we will address the role of the immune system in the vulnerability and enhanced sensitivity to drugs of abuse after social stress. We will explore in depth the effects seen in the inflammatory system in response to social stress and how they enhance the rewarding effects of drugs such as alcohol or cocaine. To conclude, we will consider pharmacological and environmental interventions that seek to influence the inflammatory response to social stress and diminish increased drug intake, as well as the translational potential and future directions of this exciting new field of research.
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Affiliation(s)
- S Montagud-Romero
- Department of Psychology and Sociology, University of Zaragoza, Teruel, Spain
| | - J Miñarro
- Department of Psychobiology, Facultad de Psicología, Universitat de Valencia, Valencia, Spain.,Red Temática de Investigación Cooperativa en Salud (RETICS-Trastornos Adictivos), Instituto de Salud Carlos III, MICINN and FEDER, Madrid, Spain
| | - M Rodríguez-Arias
- Department of Psychobiology, Facultad de Psicología, Universitat de Valencia, Valencia, Spain. .,Red Temática de Investigación Cooperativa en Salud (RETICS-Trastornos Adictivos), Instituto de Salud Carlos III, MICINN and FEDER, Madrid, Spain.
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DeMorrow S, Cudalbu C, Davies N, Jayakumar AR, Rose CF. 2021 ISHEN guidelines on animal models of hepatic encephalopathy. Liver Int 2021; 41:1474-1488. [PMID: 33900013 PMCID: PMC9812338 DOI: 10.1111/liv.14911] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 03/05/2021] [Accepted: 04/01/2021] [Indexed: 02/07/2023]
Abstract
This working group of the International Society of Hepatic Encephalopathy and Nitrogen Metabolism (ISHEN) was commissioned to summarize and update current efforts in the development and characterization of animal models of hepatic encephalopathy (HE). As defined in humans, HE in animal models is based on the underlying degree and severity of liver pathology. Although hyperammonemia remains the key focus in the pathogenesis of HE, other factors associated with HE have been identified, together with recommended animal models, to help explore the pathogenesis and pathophysiological mechanisms of HE. While numerous methods to induce liver failure and disease exist, less have been characterized with neurological and neurobehavioural impairments. Moreover, there still remains a paucity of adequate animal models of Type C HE induced by alcohol, viruses and non-alcoholic fatty liver disease; the most common etiologies of chronic liver disease.
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Affiliation(s)
- S DeMorrow
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Texas, USA; Department of Internal Medicine, Dell Medical School, The University of Texas at Austin, Texas, USA; Research division, Central Texas Veterans Healthcare System, Temple Texas USA.,Correspondance: Sharon DeMorrow, PhD, ; tel: +1-512-495-5779
| | - C Cudalbu
- Center for Biomedical Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - N Davies
- Institute for Liver and Digestive Health, University College London, Royal Free Campus, London, United Kingdom
| | - AR Jayakumar
- General Medical Research, Neuropathology Section, R&D Service and South Florida VA Foundation for Research and Education Inc; Obstetrics, Gynecology and Reproductive Sciences, University of Miami School of Medicine, Miami FL, USA
| | - CF Rose
- Hepato-Neuro Laboratory, CRCHUM, Université de Montréal, Montreal, Canada
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Motaghinejad M, Mashayekh R, Motevalian M, Safari S. The possible role of CREB-BDNF signaling pathway in neuroprotective effects of minocycline against alcohol-induced neurodegeneration: molecular and behavioral evidences. Fundam Clin Pharmacol 2021; 35:113-130. [PMID: 32579730 DOI: 10.1111/fcp.12584] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Revised: 05/02/2020] [Accepted: 06/18/2020] [Indexed: 12/17/2022]
Abstract
Abuse of alcohol triggers neurodegeneration in human brain. Minocycline has characteristics conferring neuroprotection. Current study evaluates the role of the CREB-BDNF signaling pathway in mediating minocycline's neuroprotective effects against alcohol-induced neurodegeneration. Seventy adult male rats were randomly split into groups 1 and 2 that received saline and alcohol (2 g/kg/day by gavage, once daily), respectively, and groups 3, 4, 5, and 6 were treated simultaneously with alcohol and minocycline (10, 20, 30 and 40 mg/kg I.P, respectively) for 21 days. Group 7 received minocycline alone (40 mg/kg, i.p) for 21 days. Morris water maze (MWM) has been used to assess cognitive activity. Hippocampal neurodegenerative and histological parameters as well as cyclic AMP response element-binding protein (CREB) and brain-derived neurotrophic factor (BDNF) levels were assessed. Alcohol impaired cognition, and concurrent therapy with various minocycline doses attenuated alcohol-induced cognition disturbances. Additionally, alcohol administration boosted lipid peroxidation and levels of glutathione in oxidized form (GSSG), tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β), and Bax protein, while decreased reducing type of glutathione (GSH), Bcl-2 protein, phosphorylated CREB, and BDNF levels in rat hippocampus. Alcohol also decreased the activity in the hippocampus of superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GR). In comparison, minocycline attenuated alcohol-induced neurodegeneration; elevating expression levels of P-CREB and BDNF and inhibited alcohol induced histopathological changes in both dentate gyrus (DG) and CA1 of hippocampus. Thus, minocycline is likely to provide neuroprotection against alcohol-induced neurodegeneration through mediation of the P-CREB/BDNF signaling pathway.
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Affiliation(s)
- Majid Motaghinejad
- Razi Drug Research Center, Iran University of Medical Sciences, Tehran, Iran.,Department of Pharmacology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Roya Mashayekh
- Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Chemistry, Pharmaceutical Sciences Branch, Islamic Azad University (IUAPS), Tehran, Iran
| | - Manijeh Motevalian
- Razi Drug Research Center, Iran University of Medical Sciences, Tehran, Iran.,Department of Pharmacology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Sepideh Safari
- Razi Drug Research Center, Iran University of Medical Sciences, Tehran, Iran
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6
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Motaghinejad M, Farokhi N, Motevalian M, Safari S. Molecular, histological and behavioral evidences for neuroprotective effects of minocycline against nicotine-induced neurodegeneration and cognition impairment: Possible role of CREB-BDNF signaling pathway. Behav Brain Res 2020; 386:112597. [PMID: 32198107 DOI: 10.1016/j.bbr.2020.112597] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 03/02/2020] [Indexed: 12/25/2022]
Abstract
AIM Neurodegeneration is one of the serious adverse effects of stimulant agents such as nicotine. Minocycline possess established neuroprotective properties. The role of CREB-BDNF signaling pathway in mediating the neuroprotective effects of minocycline against nicotine-induced neurodegeneration in rats was evaluated in current study. METHODS Seventy adult male rats were divided randomly into seven groups. Group 1 and 2, received 0.7 ml/rat of normal saline (i.p) and nicotine (10 mg/kg, s.c) respectively. Groups 3, 4, 5 and 6, treated concurrently with nicotine (10 mg/kg) and minocycline (10, 20, 30 and 40 mg/kg, i.p, respectively) for 21 days. Group 7 received minocycline alone (40 mg/kg, i.p) for 21 days. From 17th to 21 st days of experiment, Morris water maze (MWM) was used to evaluate learning and spatial memory in rats treated in different groups. According to the critical role of hippocampus in cognitive behavior, hippocampal neurodegenerative parameters (oxidative stress and inflammatory biomarkers) and also cyclic AMP response element binding protein (CREB) and brain-derived neurotrophic factor (BDNF) levels were evaluated in isolated hippocampus in day 22 of experiment and after drug treatment. Also hippocampal cell density and tissue changes were evaluated by hematoxylin and eosin staining. RESULT Nicotine administration impaired the learning and spatial memory in rats and simultaneous treatment with various doses of minocycline attenuated the nicotine-induced cognition disturbances. In addition, nicotine treatment increased lipid peroxidation and the levels of oxidized form of glutathione (GSSG), interleukin 1 beta (IL-1β), tumor necrosis factor alpha (TNF-α), and Bax protein, while decreasing reduced form of glutathione (GSH), Bcl-2 protein, P-CREB and BDNF levels in the hippocampus of experimental animals. Nicotine also reduced the activity of superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GR) in the hippocampus. Minocycline attenuated nicotine-induced neurodegeneration and elevating CREB (both forms) and BDNF levels. Also minocycline treatment alone increases the cognitive activity and increased CREB (both forms) and BDNF levels and decreased oxidative stress, inflammation and apoptotic biomarkers. Minocycline at high doses cause inhibition of nicotine induced cell density and changes in both area of dentate gyrus (DG) and CA1 in hippocampus. CONCLUSION It can be concluded that minocycline, probably through activation of P-CREB/BDNF signaling pathway, confers neuroprotection against nicotine-induced neurodegeneration in rat hippocampus.
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Affiliation(s)
- Majid Motaghinejad
- Razi Drug Research Center, Iran University of Medical Sciences, Tehran, Iran.
| | - Negin Farokhi
- Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Chemistry, Pharmaceutical Sciences Branch, Islamic Azad University (IUAPS), Tehran, Iran
| | - Manijeh Motevalian
- Razi Drug Research Center, Iran University of Medical Sciences, Tehran, Iran; Department of Pharmacology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Sepideh Safari
- Razi Drug Research Center, Iran University of Medical Sciences, Tehran, Iran
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7
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Salehi P, Shahmirzadi ZY, Mirrezaei FS, Shirvani Boushehri F, Mayahi F, Songhori M, Abofazeli M, Motaghinejad M, Safari S. A hypothetic role of minocycline as a neuroprotective agent against methylphenidate-induced neuronal mitochondrial dysfunction and tau protein hyper-phosphorylation: Possible role of PI3/Akt/GSK3β signaling pathway. Med Hypotheses 2019; 128:6-10. [PMID: 31203911 DOI: 10.1016/j.mehy.2019.04.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 04/14/2019] [Accepted: 04/23/2019] [Indexed: 02/08/2023]
Abstract
The underlining mechanism in neural mitochondrial dysfunction and consequences neurotoxicity, and cognitive behavior after methylphenidate (MPH) prolonged uses is unclear and proposing of therapeutic approaches for treatment of these types of neurotoxicity is one of the main goals of scientist in this manner. MPH-induced mitochondrial dysfunction in neural cells caused induction of oxidative stress, apoptosis, inflammation and cognition impairment, which leads to neurotoxicity, was reported previously but role of key neural cells proteins and involved signaling pathway in this manner remained indeterminate. Tau protein aggregation is a biomarker for mitochondrial dysfunction, neurodegenerative event and cognition impairment. Tau aggregation occur by stimulation effects of Glycogen synthase kinase-3(GSK3β) and phosphatidylinositol 3-kinase (PI3K) which activates protein kinase B(Akt) and causes inhibition of phosphorylation(activation) of GSK3β, thus Akt activation can cause inhibition of tau aggregation (hyper-phosphorylation). Management of mentioned MPH-induced mitochondrial dysfunction and consequences of neurotoxicity, and cognitive behavior through a new generation neuroprotective combination, based on modulation of disturbed in Akt function and inhibition of GSK3β and tau hyper-phosphorylation can be a prefect therapeutic interventions. Therefore, finding, introduction and development of new neuroprotective properties and explanation of their effects with potential capacity for modulation of tau hyper-phosphorylation via PI3/Akt/GSK signaling pathway is necessitated. During recent years, using new neuroprotective compounds with therapeutic probability for treatment of psychostimulant-induced mitochondrial dysfunction, neurotoxicity and cognitive malicious effects have been amazingly increased. Many previous studies have reported the neuroprotective roles of minocycline (a broad-spectrum and long-acting antibiotic) in multiple neurodegenerative events and diseases in animal model. But the role of neuroprotective effects of this agent against MPH induced mitochondrial dysfunction, neurotoxicity and cognitive malicious and also role of tau hyper-phosphorylation by modulation of PI3/Akt/GSK signaling pathway in this manner remain unknown. Thus we suggested and theorized that by using minocycline in MPH addicted subject, it would provide neuroprotection against MPH-induced mitochondrial dysfunction, neurotoxicity and cognitive malicious. Also we hypothesized that minocycline, via modulation of PI3/Akt/GSK and inhibition of tau hyper-phosphorylation, can inhibit MPH-induced mitochondrial dysfunction, neurotoxicity and cognitive malicious. In this article, we tried to discuss our hypothesis regarding the possible role of minocycline, as a powerful neuroprotective agent, and also role of tau hyper-phosphorylation related to PI3/Akt/GSK signaling pathway in treatment of MPH-induced mitochondrial dysfunction, neurotoxicity and cognitive disturbance.
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Affiliation(s)
- Pegah Salehi
- Research Center for Addiction and Risky Behaviors (ReCARB), Iran Psychiatric Center, Iran University of Medical Sciences, Tehran, Iran
| | - Zhara Yaraei Shahmirzadi
- Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Chemistry, Pharmaceutical Sciences Branch, Islamic Azad University (IUAPS), Tehran, Iran
| | - Fatemeh Sadat Mirrezaei
- Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Chemistry, Pharmaceutical Sciences Branch, Islamic Azad University (IUAPS), Tehran, Iran
| | - Farima Shirvani Boushehri
- Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Chemistry, Pharmaceutical Sciences Branch, Islamic Azad University (IUAPS), Tehran, Iran
| | - Fatemeh Mayahi
- Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Chemistry, Pharmaceutical Sciences Branch, Islamic Azad University (IUAPS), Tehran, Iran
| | - Mojtaba Songhori
- Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Chemistry, Pharmaceutical Sciences Branch, Islamic Azad University (IUAPS), Tehran, Iran
| | - Maryam Abofazeli
- Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Chemistry, Pharmaceutical Sciences Branch, Islamic Azad University (IUAPS), Tehran, Iran
| | - Majid Motaghinejad
- Research Center for Addiction and Risky Behaviors (ReCARB), Iran Psychiatric Center, Iran University of Medical Sciences, Tehran, Iran.
| | - Sepideh Safari
- Razi Drug Research Center, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
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Mohammadian F, Firouzjaei MA, Haghani M, Shabani M, Shid Moosavi SM, Mohammadi F. Inhibition of inflammation is not enough for recovery of cognitive impairment in hepatic encephalopathy: Effects of minocycline and ibuprofen. Brain Res Bull 2019; 149:96-105. [PMID: 31005662 DOI: 10.1016/j.brainresbull.2019.04.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 04/14/2019] [Accepted: 04/16/2019] [Indexed: 12/12/2022]
Abstract
There is evidence that hyperammonia and inflammation play crucial roles in hepatic encephalopathy. This study intends to determine neuroprotective effects of minocycline (MINO) and ibuprofen (IBU), and also set out to assess whether inhibition of inflammation is enough to achieve optimal improvement of hepatic encephalopathy symptoms. The hepatic encephalopathy was induced by bile-duct ligation (BDL), and the animals received first dose of MINO and/or IBU 15 days later and then every day until the 28 day. The rats were divided into the 6 groups of control, sham, BDL + V and BDL + IBU, BDL + MINO and BDL + MINO + IBU, which each group had 3 sub-groups for evaluations of blood-brain barrier (BBB), memory performance, synaptic-plasticity and apoptosis. The long-term potentiation (LTP) and short-term potentiation were evaluated by field potential recording. The memory performance, apoptosis and BBB integrity were assessed via passive avoidance, Western-blotting of caspase-3 and Evans-blue dye extravasation, respectively. The MINO, IBU or their co-treatment in the BDL rats did not improve liver dysfunction. The BDL increased hippocampal apoptosis and BBB disruption, which were fully recovered by all three pharmacological interventions. The MINO treatment alone or combined with IBU had similar neuroprotective effects on the BDL-induced disturbances of hippocampal basal synaptic transmission, LTP and memory performance, whereas they were not ameliorated by the single IBU therapy. Therefore, it seems likely that inhibition of inflammation is not able to improve functionally impaired memory and LTP in the hepatic encephalopathy, and they may be recovered by the direct neuroprotective effects of the MINO.
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Affiliation(s)
- Fatemeh Mohammadian
- Department of Physiology, Shiraz University of Medical Sciences, Shiraz, Iran.
| | | | - Masoud Haghani
- Department of Physiology, Shiraz University of Medical Sciences, Shiraz, Iran; Clinical Neurology Research Centre, Shiraz University of Medical Sciences, Shiraz, Iran.
| | - Mohammad Shabani
- Neuroscience Research Centre, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran.
| | | | - Fatemeh Mohammadi
- Neuroscience Research Centre, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran.
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9
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Heidari R. Brain mitochondria as potential therapeutic targets for managing hepatic encephalopathy. Life Sci 2019; 218:65-80. [DOI: 10.1016/j.lfs.2018.12.030] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 12/08/2018] [Accepted: 12/16/2018] [Indexed: 02/07/2023]
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10
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Motaghinejad M, Safari S, Feizipour S, Sadr S. Crocin may be useful to prevent or treatment of alcohol induced neurodegeneration and neurobehavioral sequels via modulation of CREB/BDNF and Akt/GSK signaling pathway. Med Hypotheses 2019; 124:21-25. [PMID: 30798909 DOI: 10.1016/j.mehy.2019.01.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 01/12/2019] [Accepted: 01/23/2019] [Indexed: 12/28/2022]
Abstract
The neurodegeneration and neurobehavioral consequences of alcohol are serious and offering therapeutic approaches for management of these types of neurodegeneration is one of the main concerns of researchers in this manner. Alcohol-stimulated oxidative stress, apoptosis and inflammation, with modulation of involved signaling pathway in neuroprotection, was reported previously. Neuroprotective strategy for management of alcohol induced neurodegeneration through a new generation neuroprotective agent and based on modulation of some neuroprotective signaling pathway such as CREB/BDNF and Akt/GSK has always been superior to any other therapeutic interventions. Therefore, the introduction and development of potential new neuroprotective properties and clarification of their effects on major cell signaling such as CREB/BDNF and Akt/GSK is necessitated. During recent years, using new neuroprotective compounds with therapeutic probability for treatment of alcohol induced neuro-biochemical and neuro-behavioral malicious effects have been amazingly increased. Many previous studies have reported the neuroprotective roles of crocin (major active component of saffron) in multiple neurodegenerative events and diseases in animal model. But the role of crocin neuroprotective effects against alcohol induced neurodegeneration and neurobehavioral sequels and also role of CREB/BDNF and Akt/GSK in this manner remain unclear. Hence we hypothesized that by using crocin in alcohol dependent subject it would provide neuroprotection against alcohol induced neurodegeneration and neurobehavioral and probably can manage sequels of alcohol abuses. Also we hypothesized that crocin, via intonation of CREB/BDNF and Akt/GSK signaling pathway, can inhibit alcohol induced neurodegeneration. In this article, we tried to discuss our hypothesis regarding the possible role of crocin, as a potent neuroprotective agent, and also role of Akt/GSK and CREB/BDNF signaling pathway in treatment of alcohol induced neurodegeneration and neurobehavioral through its anti-inflammatory,anti-apoptotic, anti-oxidative stress and cognitive enhancer.
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Affiliation(s)
- Majid Motaghinejad
- Research Center for Addiction and Risky Behaviors (ReCARB), Iran Psychiatric Center, Iran University of Medical Sciences, Tehran, Iran.
| | - Sepideh Safari
- Razi Drug Research Center, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Saba Feizipour
- Department of Medicinal Chemistry, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
| | - Samira Sadr
- Research and Development Department, Parsian-Exir-Aria pharmaceutical Company, Tehran, Iran
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11
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Luo S, Kong X, Wu JR, Wang CY, Tian Y, Zheng G, Su YY, Lu GM, Zhang LJ, Yang GF. Neuroinflammation in acute hepatic encephalopathy rats: imaging and therapeutic effectiveness evaluation using 11C-PK11195 and 18F-DPA-714 micro-positron emission tomography. Metab Brain Dis 2018; 33:1733-1742. [PMID: 29968208 DOI: 10.1007/s11011-018-0282-7] [Citation(s) in RCA: 5] [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: 03/23/2018] [Accepted: 06/27/2018] [Indexed: 02/06/2023]
Abstract
Neuroinflammation has an important influence in pathogenesis of acute hepatic encephalopathy (AHE). 11C-PK11195 and 18F-DPA-714 targeted to translocator protein (TSPO) have potential application in positron emission tomography (PET) as a molecular probe of neuroinflammation. The aim of this study was to compare these two radiotracers and their effectiveness in detecting neuroinflammation for the imaging of AHE rat models. Furthermore, using the new radiotracer 18F-DPA-714, we analyzed the effectiveness of therapeutic treatment for neuroinflammation in AHE. First, we performed a comparative study of 11C-PK1195 and 18F-DPA-714 PET to image neuroinflammation in AHE rats induced by thioacetamide. Twenty-four rats were divided into either control group (n = 12) or AHE group (n = 12). Next, each group was subdivided depending on the radiotracer used during PET imaging (n = 6). Radiotracer uptake values encompassing the whole brain were compared. Lastly, we used the optimized tracer to monitor anti-neuroinflammation effects in AHE-induced rats. Forty-six rats were divided into four groups: [normal saline (NS) group (n = 13), minocycline (MINO) group (n = 11), dexamethasone (DEXA) group (n = 11), MINO+DEXA group (n = 11)]. 18F-DPA-714 PET was performed and the uptake values were calculated. The rotarod test, biochemical indices, and histopathological examinations were quantitatively measured and compared. AHE rats showed reduced motor ability, elevated ammonia levels, and higher liver function indices (all P < 0.05) with unchanged inflammatory factors (all P > 0.05), compared to control group. Both 11C-PK11195 and 18F-DPA-714 PET can detect neuroinflammation of AHE rats. Behavioral studies showed that MINO and/or DEXA improved the motor ability in AHE rats (P < 0.05); however, no differences were found for liver function or inflammatory markers among the four groups (all P > 0.05). The average uptake values of whole brain and multiple brain areas in the MINO+DEXA group were lower compared to all other groups (all P < 0.05), which was demonstrated by CD11b stains of microglia. Our results show that both 11C-PK11195 and 18F-DPA-714 PET can detect neuroinflammation in AHE-induced rat models. Additionally, the combined use of minocycline and dexamethasone can effectively inhibit neuroinflammation in AHE-induced rats, which can be sensitively monitored by 18F-DPA-714 PET.
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Affiliation(s)
- Song Luo
- Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, 305 Zhongshan East Road, Nanjing, 210002, Jiangsu, China
| | - Xiang Kong
- Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, 305 Zhongshan East Road, Nanjing, 210002, Jiangsu, China
| | - Jin Rong Wu
- Department of Pathology, Jinling Hospital, Medical School of Nanjing University, Nanjing, 210002, Jiangsu, China
| | - Chun Yan Wang
- Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, 305 Zhongshan East Road, Nanjing, 210002, Jiangsu, China
| | - Ying Tian
- Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, 305 Zhongshan East Road, Nanjing, 210002, Jiangsu, China
| | - Gang Zheng
- Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, 305 Zhongshan East Road, Nanjing, 210002, Jiangsu, China
| | - Yun Yan Su
- Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, 305 Zhongshan East Road, Nanjing, 210002, Jiangsu, China
| | - Guang Ming Lu
- Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, 305 Zhongshan East Road, Nanjing, 210002, Jiangsu, China
| | - Long Jiang Zhang
- Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, 305 Zhongshan East Road, Nanjing, 210002, Jiangsu, China.
| | - Gui Fen Yang
- Department of Nuclear Medicine, Jinling Hospital, Medical School of Nanjing University, Nanjing, 210002, Jiangsu, China.
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12
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Dhanda S, Sunkaria A, Halder A, Sandhir R. Mitochondrial dysfunctions contribute to energy deficits in rodent model of hepatic encephalopathy. Metab Brain Dis 2018; 33:209-223. [PMID: 29138968 DOI: 10.1007/s11011-017-0136-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 10/12/2017] [Indexed: 12/12/2022]
Abstract
Perturbations in the cerebral energy metabolism are anticipated to be an important factor by which ammonia may exert its toxic effects on the central nervous system. The present study was designed to investigate the role of impaired mitochondrial functions and cerebral energy metabolism in the development hepatic encephalopathy (HE) induced by of bile duct ligation (BDL). After four weeks of BDL, a significant increase in hepatic hydroxyproline and collagen content was observed which confirmed biliary fibrosis. Brain regions viz. cortex, hippocampus, striatum and cerebellum of BDL rats had impaired activity of mitochondrial respiratory chain enzymes. This was accompanied by increase in mitochondrial reactive oxygen species (ROS), malondialdehyde (MDA) and protein carbonyl levels in the brain. Mitochondrial redox ratio was significantly reduced in the brain of BDL rats. In addition, mitochondria from brain of BDL rats were depolarized and swollen compared to the sham controls. Ultrastructure analysis of mitochondria from cortex and hippocampus of BDL animals revealed aberrant cristae, ruptured membranes and non-dense matrix. Further, a significant decrease was observed in creatine kinase activity, glucose uptake and CO2 production in the brain regions of BDL rats. ATP/ADP ratio, a critical parameter of cellular energy status, was also significantly reduced in brain regions of rats with HE. Overall, the findings clearly demonstrate that BDL induced HE involves mitochondrial respiratory chain dysfunctions, mitochondrial depolarization and swelling that accentuates oxidative stress which in turn leads to compromise in cerebral energy metabolism thereby contributing to the pathophysiology of chronic HE.
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Affiliation(s)
- Saurabh Dhanda
- Department of Biochemistry, Panjab University, Basic Medical Science Block-II, Sector-25, Chandigarh, 160014, India
| | - Aditya Sunkaria
- Department of Biochemistry, Panjab University, Basic Medical Science Block-II, Sector-25, Chandigarh, 160014, India
| | - Avishek Halder
- Department of Biochemistry, Panjab University, Basic Medical Science Block-II, Sector-25, Chandigarh, 160014, India
| | - Rajat Sandhir
- Department of Biochemistry, Panjab University, Basic Medical Science Block-II, Sector-25, Chandigarh, 160014, India.
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13
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Saracyn M, Czarzasta K, Brytan M, Murawski P, Lewicki S, Ząbkowski T, Zdanowski R, Cudnoch-Jędrzejewska A, Kamiński GW, Wańkowicz Z. Role of Nitric Oxide Pathway in Development and Progression of Chronic Kidney Disease in Rats Sensitive and Resistant to its Occurrence in an Experimental Model of 5/6 Nephrectomy. Med Sci Monit 2017; 23:4865-4873. [PMID: 29018182 PMCID: PMC5649515 DOI: 10.12659/msm.903820] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Understanding the mechanisms conditioning development of chronic kidney disease (CKD) is still a challenge. The aim of this study was to evaluate the activity of the intrarenal nitric oxide (NO) pathway in the context of sensitivity or resistance of different animal strains to the development and degree of renal failure. MATERIAL AND METHODS Two rat strains were used: Wistar (WR) and Sprague-Dawley rats (SDR) in a model of CKD - 5/6 nephrectomy. We assessed parameters of renal failure and expression of nitric oxide synthase (NOS) isoforms in renal cortex and medulla. RESULTS We did not observe renal failure in WR, and CKD developed in SDR with increase of creatinine and urea concentration as well as decrease of diuresis and glomerular filtration. In the renal cortex, baseline expression of NOS2 was higher in WR than in SDR. 5/6 nephrectomy resulted in reduction of NOS2 in both strains and NOS3 in WR. In the renal medulla, baseline NOS2 expression was higher in SDR, and nephrectomy resulted in its decrease only in SDR. Although baseline NOS3 expression was higher in SDR, the NOS3 expression after nephrectomy was higher in WR rats. CONCLUSIONS In model of CKD - 5/6 nephrectomy, SDR proved to be sensitive and WR resistant to development of CKD. The intrarenal activity of the nitric oxide pathway was the factor that differentiated both strains. This mechanism may be responsible for insensitivity of WR to development of renal failure in this model of CKD.
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Affiliation(s)
- Marek Saracyn
- Department of Endocrinology and Isotope Therapy, Military Institute of Medicine, Warsaw, Poland.,Department of Internal Diseases, Nephrology, and Dialysis, Military Institute of Medicine, Warsaw, Poland
| | - Katarzyna Czarzasta
- Department of Experimental and Clinical Physiology, Laboratory Centre for Preclinical Research, Medical University of Warsaw, Warsaw, Poland
| | - Marek Brytan
- Department of Pharmacology and Toxicology, Military Institute of Hygiene and Epidemiology, Warsaw, Poland
| | - Piotr Murawski
- Department of Information Technology, Military Institute of Medicine, Warsaw, Poland
| | - Sławomir Lewicki
- Department of Regenerative Medicine, Military Institute of Hygiene and Epidemiology, Warsaw, Poland
| | - Tomasz Ząbkowski
- Department of Urology, Military Institute of Medicine, Warsaw, Poland
| | - Robert Zdanowski
- Department of Regenerative Medicine, Military Institute of Hygiene and Epidemiology, Warsaw, Poland
| | | | | | - Zofia Wańkowicz
- Department of Internal Diseases, Nephrology, and Dialysis, Military Institute of Medicine, Warsaw, Poland
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14
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Hadjihambi A, Arias N, Sheikh M, Jalan R. Hepatic encephalopathy: a critical current review. Hepatol Int 2017; 12:135-147. [PMID: 28770516 PMCID: PMC5830466 DOI: 10.1007/s12072-017-9812-3] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Accepted: 07/06/2017] [Indexed: 12/12/2022]
Abstract
Hepatic encephalopathy (HE) is a serious neuropsychiatric complication of cirrhosis and/or porto-systemic shunting. The clinical symptoms are widely variable, extending from subtle impairment in mental state to coma. The utility of categorizing the severity of HE accurately and efficiently serves not only to provide practical functional information about the current clinical status of the patient but also gives valuable prognostic information. In the past 20–30 years, there has been rapid progress in understanding the pathophysiological basis of HE; however, the lack of direct correlation between pathogenic factors and the severity of HE make it difficult to select appropriate therapy for HE patients. In this review, we will discuss the classification system and its limitations, the neuropsychometric assessments and their challenges, as well as the present knowledge on the pathophysiological mechanisms. Despite the many prevalent hypotheses around the pathogenesis of the disease, most treatments focus on targeting and lowering the accumulation of ammonia as well as inflammation. However, treatment of minimal HE remains a huge unmet need and a big concerted effort is needed to better define this condition to allow the development of new therapies. We review the currently available therapies and future approaches to treat HE as well as the scientific and clinical data that support their effectiveness.
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Affiliation(s)
- Anna Hadjihambi
- Division of Medicine, UCL Medical School, Royal Free Hospital, UCL Institute for Liver and Digestive Health, Rowland Hill Street, London, NW3 2PF, UK.,Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, London, WC1E 6BT, UK
| | - Natalia Arias
- Division of Medicine, UCL Medical School, Royal Free Hospital, UCL Institute for Liver and Digestive Health, Rowland Hill Street, London, NW3 2PF, UK.,INEUROPA (Instituto de Neurociencias del Principado de Asturias), Oviedo, Spain
| | - Mohammed Sheikh
- Division of Medicine, UCL Medical School, Royal Free Hospital, UCL Institute for Liver and Digestive Health, Rowland Hill Street, London, NW3 2PF, UK
| | - Rajiv Jalan
- Division of Medicine, UCL Medical School, Royal Free Hospital, UCL Institute for Liver and Digestive Health, Rowland Hill Street, London, NW3 2PF, UK.
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15
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Li SW, Chen YC, Sheen JM, Hsu MH, Tain YL, Chang KA, Huang LT. Minocycline restores cognitive-relative altered proteins in young bile duct-ligated rat prefrontal cortex. Life Sci 2017; 180:75-82. [PMID: 28366719 DOI: 10.1016/j.lfs.2017.03.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 03/24/2017] [Accepted: 03/29/2017] [Indexed: 01/06/2023]
Abstract
AIMS Bile duct ligation (BDL) model is used to study hepatic encephalopathy accompanied by cognitive impairment. We employed the proteomic analysis approach to evaluate cognition-related proteins in the prefrontal cortex of young BDL rats and analyzed the effect of minocycline on these proteins and spatial memory. MAIN METHODS BDL was induced in young rats at postnatal day 17. Minocycline as a slow-release pellet was implanted into the peritoneum. Morris water maze test and two-dimensional liquid chromatography-tandem mass spectrometry were used to evaluate spatial memory and prefrontal cortex protein expression, respectively. We used 2D/LC-MS/MS to analyze for affected proteins in the prefrontal cortex of young BDL rats. Results were verified with Western blotting, immunohistochemistry, and quantitative real-time PCR. The effect of minocycline in BDL rats was assessed. KEY FINDINGS BDL induced spatial deficits, while minocycline rescued it. Collapsin response mediator protein 2 (CRMP2) and manganese-dependent superoxide dismutase (MnSOD) were upregulated and nucleoside diphosphate kinase B (NME2) was downregulated in young BDL rats. BDL rats exhibited decreased levels of brain-derived neurotrophic factor (BDNF) mRNA as compared with those by the control. However, minocycline treatment restored CRMP2 and NME2 protein expression, BDNF mRNA level, and MnSOD activity to control levels. SIGNIFICANCE We demonstrated that BDL altered the expression of CRMP2, NME2, MnSOD, and BDNF in the prefrontal cortex of young BDL rats. However, minocycline treatment restored the expression of the affected mediators that are implicated in cognition.
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Affiliation(s)
- Shih-Wen Li
- Department of Pediatrics, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan; Department of Medical Research, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| | - Yu-Chieh Chen
- Department of Pediatrics, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Jiunn-Ming Sheen
- Department of Pediatrics, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan; Department of Medical Research, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| | - Mei-Hsin Hsu
- Department of Pediatrics, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - You-Lin Tain
- Department of Pediatrics, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Kow-Aung Chang
- Department of Anesthesiolgy, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Li-Tung Huang
- Department of Pediatrics, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan; Department of Traditional Medicine, Chang Gung University, Linkow, Taiwan.
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16
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Jang SY, Chang JY. Pathophysiology and Treatment of Cerebral Edema in Acute Liver Failure. JOURNAL OF NEUROCRITICAL CARE 2016. [DOI: 10.18700/jnc.160088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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17
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Patel VC, White H, Støy S, Bajaj JS, Shawcross DL. Clinical science workshop: targeting the gut-liver-brain axis. Metab Brain Dis 2016; 31:1327-1337. [PMID: 26446022 DOI: 10.1007/s11011-015-9743-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2015] [Accepted: 10/02/2015] [Indexed: 02/08/2023]
Abstract
A clinical science workshop was held at the ISHEN meeting in London on Friday 11th September 2014 with the aim of thrashing out how we might translate what we know about the central role of the gut-liver-brain axis into targets which we can use in the treatment of hepatic encephalopathy (HE). This review summarises the integral role that inter-organ ammonia metabolism plays in the pathogenesis of HE with specific discussion of the roles that the small and large intestine, liver, brain, kidney and muscle assume in ammonia and glutamine metabolism. Most recently, the salivary and gut microbiome have been shown to underpin the pathophysiological changes which culminate in HE and patients with advanced cirrhosis present with enteric dysbiosis with small bowel bacterial overgrowth and translocation of bacteria and their products across a leaky gut epithelial barrier. Resident macrophages within the liver are able to sense bacterial degradation products initiating a pro-inflammatory response within the hepatic parenchyma and release of cytokines such as tumour necrosis factor alpha (TNF-α) and interleukin-8 into the systemic circulation. The endotoxemia and systemic inflammatory response that are generated predispose both to the development of infection as well as the manifestation of covert and overt HE. Co-morbidities such as diabetes and insulin resistance, which commonly accompany cirrhosis, may promote slow gut transit, promote bacterial overgrowth and increase glutaminase activity and may need to be acknowledged in HE risk stratification assessments and therapeutic regimens. Therapies are discussed which target ammonia production, utilisation or excretion at an individual organ level, or which reduce systemic inflammation and endotoxemia which are known to exacerbate the cerebral effects of ammonia in HE. The ideal therapeutic strategy would be to use an agent that can reduce hyperammonemia and reduce systemic inflammation or perhaps to adopt a combination of therapies that can address both.
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Affiliation(s)
- Vishal C Patel
- Institute of Liver Studies, King's College London School of Medicine, King's College Hospital, King's College Hospital, Denmark Hill, London, SE5 9RS, UK
| | - Helen White
- Institute of Liver Studies, King's College London School of Medicine, King's College Hospital, King's College Hospital, Denmark Hill, London, SE5 9RS, UK
| | - Sidsel Støy
- Institute of Liver Studies, King's College London School of Medicine, King's College Hospital, King's College Hospital, Denmark Hill, London, SE5 9RS, UK
| | - Jasmohan S Bajaj
- McGuire VA Medical Center, Virginia Commonwealth University, Richmond, VA, USA
| | - Debbie L Shawcross
- Institute of Liver Studies, King's College London School of Medicine, King's College Hospital, King's College Hospital, Denmark Hill, London, SE5 9RS, UK.
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18
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Milewski K, Oria M. What we know: the inflammatory basis of hepatic encephalopathy. Metab Brain Dis 2016; 31:1239-1247. [PMID: 26497651 DOI: 10.1007/s11011-015-9740-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 09/24/2015] [Indexed: 02/07/2023]
Abstract
Central Nervous System (CNS) degeneration appearing in patients with cirrhosis is responsible for cognitive and persistent motor impairments that lead to an important impact on life quality. Brain injury affects certain areas of the CNS that might affect two types of cells: neurons and astrocytes. The process leading to brain injury could be induced by portosystemic shunting accompanied by hyperammonemia and by the activation of peripheral inflammation, manifested as episodic encephalopathy. Hyperammonemia combined with a decrease on the BCA/AAA ratio induces alterations of energetic metabolism and the formation of free radicals in the CNS. This process would be stimulated by the activation of peripheral inflammatory mediators that could act on receptors of the blood brain barrier such as TLR4, activating inflammatory responses in the CNS. As a result, a persistent activation of microglia and an irreversible neuronal and astrocytic injury would be induced. A new knowledge of the mechanisms leading to brain injury in cirrhosis would develop protective strategies to correct changes of nitrogen metabolism and inflammation.
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Affiliation(s)
- K Milewski
- Department of Neurotoxicology, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawińskiego 5 Str, 02-106, Warsaw, Poland
| | - M Oria
- Translational Research in Fetal Surgery for Congenital Malformations, Center for Fetal, Cellular and Molecular Therapy, Division of Pediatric General and Thoracic Surgery, Cincinnati Children's Hospital Medical Center (CCHMC), 3333 Burnet Avenue, MLC 11020, S 8.400 AT, Cincinnati, OH, 45229-3039, USA.
- Liver Failure Group, UCL Institute for Liver and Digestive Health, Royal Free Hospital, University College London, London, UK.
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19
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Wright G, Swain M, Annane D, Saliba F, Samuel D, Arroyo V, DeMorrow S, Witt A. Neuroinflammation in liver disease: sessional talks from ISHEN. Metab Brain Dis 2016; 31:1339-1354. [PMID: 27726053 DOI: 10.1007/s11011-016-9918-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 09/27/2016] [Indexed: 12/20/2022]
Abstract
At the recent ISHEN ('International Symposium of Hepatic Encephalopathy & Nitrogen Metabolism') conference in London, a whole session was dedicated to our increasing awareness of the importance of inflammation in the brain - termed 'neuroinflammation', in the development of Hepatic Encephalopathy (HE) - the neurological manifestations of advanced liver disease. In this review our ISHEN speakers further discuss the content of their sessional presentations and more broadly we discuss our understanding of the role of neuroinflammation in HE pathogenesis.
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Affiliation(s)
- Gavin Wright
- Gastroenterology Department, Basildon & Thurrock University Hospitals, Basildon, UK.
- Hepatology and Hepatobiliary Medicine, The Royal Free Hospital, Pond Street, London, NW3 2QG, UK.
- University College London, Gower Street, London, WC1E 6BT, UK.
| | - Mark Swain
- Division of Gastroenterology and Hepatology, University of Calgary, Calgary, Canada
| | - Djillali Annane
- INSERM CIC IT 805, CHU Paris IdF Ouest - Hôpital Raymond Poincaré, 104 boulevard Raymond Poincaré, 92380, Garches, France
| | - Faouzi Saliba
- Centre Hépato-Biliaire, Hôpital Paul Brousse, 12, avenue Paul vaillant Couturier, 94800, Villejuif, France
| | - Didier Samuel
- GHU Paris-Sud - Hôpital Paul Brousse, 12 avenue Paul Vaillant-Couturier, 94804, Villejuif Cedex, France
| | - Vicente Arroyo
- Liver Unit, Instiute of Digestive and Metabolic Diseases, Hopsital Clinic, University of Barcelona, Barcelona, Spain
| | - Sharon DeMorrow
- Department of Internal Medicine, Central Texas Veterans Healthcare System, VA Bld 205, 1901 South 1st Street, Temple, TX, 76504, USA
| | - Anne Witt
- Departement of Hepatology, Rigshospitalet, Blegdamsvej 9, 2100 København Ø, Copenhagen, Denmark
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20
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Minocycline ameliorates prenatal valproic acid induced autistic behaviour, biochemistry and blood brain barrier impairments in rats. Brain Res 2015; 1630:83-97. [PMID: 26551768 DOI: 10.1016/j.brainres.2015.10.052] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 10/16/2015] [Accepted: 10/29/2015] [Indexed: 01/07/2023]
Abstract
Autism is a neurodevelopment disorder. One percent worldwide population suffers with autism and males suffer more than females. Microglia plays an important role in neurodevelopment, neuropsychiatric and neurodegenerative disorders. The present study has been designed to investigate the role of minocycline in prenatal valproic acid induced autism in rats. Animals with prenatal valproic acid have reduced social interaction (three chamber social behaviour apparatus), spontaneous alteration (Y-Maze), exploratory activity (Hole board test), intestinal motility, serotonin levels (both in prefrontal cortex and ileum) and prefrontal cortex mitochondrial complex activity (complexes I, II, IV). Furthermore, prenatal valproic acid treated animals have shown an increase in locomotion (actophotometer), anxiety (elevated plus maze), brain oxidative stress (thiobarbituric acid reactive species, glutathione, catalase), nitrosative stress (nitrite/nitrate), inflammation (both in brain and ileum myeloperoxidase activity), calcium and blood brain barrier permeability. Treatment with minocycline significantly attenuated prenatal valproic acid induced reduction in social interaction, spontaneous alteration, exploratory activity intestinal motility, serotonin levels and prefrontal cortex mitochondrial complex activity. Furthermore, minocycline has also attenuated prenatal valproic acid induced increase in locomotion, anxiety, brain oxidative and nitrosative stress, inflammation, calcium and blood brain barrier permeability. Thus, it may be concluded that prenatal valproic acid has induced autistic behaviour, biochemistry and blood brain barrier impairment in animals, which were significantly attenuated by minocycline. Minocycline should be explored further for its therapeutic benefits in autism.
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21
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Zhang RZ, Qiu H, Wang N, Long FL, Mao DW. Effect of Rheum palmatum L. on NF-κB signaling pathway of mice with acute liver failure. ASIAN PAC J TROP MED 2015; 8:841-7. [DOI: 10.1016/j.apjtm.2015.09.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 08/20/2015] [Accepted: 09/15/2015] [Indexed: 02/07/2023] Open
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22
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McMillin M, Frampton G, Tobin R, Dusio G, Smith J, Shin H, Newell-Rogers K, Grant S, DeMorrow S. TGR5 signaling reduces neuroinflammation during hepatic encephalopathy. J Neurochem 2015; 135:565-76. [PMID: 26179031 DOI: 10.1111/jnc.13243] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 06/29/2015] [Accepted: 06/30/2015] [Indexed: 12/29/2022]
Abstract
Hepatic encephalopathy (HE) is a serious neurological complication of acute and chronic liver failure. Expression of the neurosteroid/bile acid receptor Takeda G protein-coupled receptor 5 (TGR5) has been demonstrated in the brain and is thought to be neuroprotective. However, it is unknown how TGR5 signaling can influence the progression and associated neuroinflammation of HE. HE was induced in C57Bl/6 mice via intraperitoneal injection of azoxymethane (AOM) and tissue was collected throughout disease progression. TGR5 expression was elevated in the frontal cortex following AOM injection in mice. The cellular localization of TGR5 was found in both neurons and microglia in the cortex of C57Bl/6 mice. Central infusion of the TGR5 agonist, betulinic acid, prior to AOM injection delayed neurological decline, increased cortical cyclic adenosine monophosphate concentrations, reduced microglia activation and proliferation, and reduced proinflammatory cytokine production. Betulinic acid treatment in vitro reduced the neuronal expression of chemokine ligand 2, a chemokine previously demonstrated to contribute to HE pathogenesis. Lastly, treatment of the microglia cell line EOC-20 with conditioned media from betulinic acid-treated primary neurons decreased phagocytic activity and cytokine production. Together, these data identify that activation of TGR5, which is up-regulated during HE, alleviates neuroinflammation and improves outcomes of AOM-treated mice through neuron and microglia paracrine signaling.
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Affiliation(s)
- Matthew McMillin
- Central Texas Veterans Healthcare System, Temple, Texas, USA.,Department of Internal Medicine, Texas A&M Health Science Center, College of Medicine, Temple, Texas, USA
| | - Gabriel Frampton
- Central Texas Veterans Healthcare System, Temple, Texas, USA.,Department of Internal Medicine, Texas A&M Health Science Center, College of Medicine, Temple, Texas, USA
| | - Richard Tobin
- Department of Surgery, Texas A&M Health Science Center and Baylor Scott & White Health, College of Medicine, Temple, Texas, USA
| | - Giuseppina Dusio
- Department of Surgery, Texas A&M Health Science Center and Baylor Scott & White Health, College of Medicine, Temple, Texas, USA
| | - Jenny Smith
- Department of Internal Medicine, Texas A&M Health Science Center, College of Medicine, Temple, Texas, USA
| | - Hope Shin
- Department of Internal Medicine, Texas A&M Health Science Center, College of Medicine, Temple, Texas, USA
| | - Karen Newell-Rogers
- Department of Surgery, Texas A&M Health Science Center and Baylor Scott & White Health, College of Medicine, Temple, Texas, USA
| | - Stephanie Grant
- Central Texas Veterans Healthcare System, Temple, Texas, USA.,Department of Internal Medicine, Texas A&M Health Science Center, College of Medicine, Temple, Texas, USA
| | - Sharon DeMorrow
- Central Texas Veterans Healthcare System, Temple, Texas, USA.,Department of Internal Medicine, Texas A&M Health Science Center, College of Medicine, Temple, Texas, USA.,Digestive Disease Research Center, Baylor Scott & White Health, Temple, Texas, USA
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Affiliation(s)
- Anna Hadjihambi
- Institute for Liver and Digestive Health, Liver Failure Group, University College London Medical School Royal Free CampusLondonUK
| | - Rajiv Jalan
- Institute for Liver and Digestive Health, Liver Failure Group, University College London Medical School Royal Free CampusLondonUK
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Weingarten MA, Sande AA. Acute liver failure in dogs and cats. J Vet Emerg Crit Care (San Antonio) 2015; 25:455-73. [PMID: 25882813 DOI: 10.1111/vec.12304] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Accepted: 01/26/2015] [Indexed: 12/14/2022]
Abstract
OBJECTIVE To define acute liver failure (ALF), review the human and veterinary literature, and discuss the etiologies and current concepts in diagnostic and treatment options for ALF in veterinary and human medicine. ETIOLOGY In veterinary medicine ALF is most commonly caused by hepatotoxin exposure, infectious agents, inflammatory diseases, trauma, and hypoxic injury. DIAGNOSIS A patient may be deemed to be in ALF when there is a progression of acute liver injury with no known previous hepatic disease, the development of hepatic encephalopathy of any grade that occurs within 8 weeks after the onset of hyperbilirubinemia (defined as plasma bilirubin >50 μM/L [>2.9 mg/dL]), and the presence of a coagulopathy. Diagnostic testing to more specifically characterize liver dysfunction or pathology is usually required. THERAPY Supportive care to aid the failing liver and compensate for the lost functions of the liver remains the cornerstone of care of patients with ALF. Advanced therapeutic options such as extracorporeal liver assist devices and transplantation are currently available in human medicine. PROGNOSIS The prognosis for ALF depends upon the etiology, the degree of liver damage, and the response to therapy. In veterinary medicine, the prognosis is generally poor.
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Aldridge DR, Tranah EJ, Shawcross DL. Pathogenesis of hepatic encephalopathy: role of ammonia and systemic inflammation. J Clin Exp Hepatol 2015; 5:S7-S20. [PMID: 26041962 PMCID: PMC4442852 DOI: 10.1016/j.jceh.2014.06.004] [Citation(s) in RCA: 168] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 06/05/2014] [Indexed: 12/12/2022] Open
Abstract
The syndrome we refer to as Hepatic Encephalopathy (HE) was first characterized by a team of Nobel Prize winning physiologists led by Pavlov and Nencki at the Imperial Institute of Experimental Medicine in Russia in the 1890's. This focused upon the key observation that performing a portocaval shunt, which bypassed nitrogen-rich blood away from the liver, induced elevated blood and brain ammonia concentrations in association with profound neurobehavioral changes. There exists however a spectrum of metabolic encephalopathies attributable to a variety (or even absence) of liver hepatocellular dysfunctions and it is this spectrum rather than a single disease entity that has come to be defined as HE. Differences in the underlying pathophysiology, treatment responses and outcomes can therefore be highly variable between acute and chronic HE. The term also fails to articulate quite how systemic the syndrome of HE can be and how it can be influenced by the gastrointestinal, renal, nervous, or immune systems without any change in background liver function. The pathogenesis of HE therefore encapsulates a complex network of interdependent organ systems which as yet remain poorly characterized. There is nonetheless a growing recognition that there is a complex but influential synergistic relationship between ammonia, inflammation (sterile and non-sterile) and oxidative stress in the pathogenesis HE which develops in an environment of functional immunoparesis in patients with liver dysfunction. Therapeutic strategies are thus moving further away from the traditional specialty of hepatology and more towards novel immune and inflammatory targets which will be discussed in this review.
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Key Words
- ATP, adenosine triphosphate
- AoCLF, acute-on-chronic liver failure
- BBB, blood–brain barrier
- CBF, cerebral blood flow
- CNS, central nervous system
- GS, glutamine synthetase
- HE, hepatic encephalopathy
- ICH, intracranial hypertension
- MHE, minimal hepatic encephalopathy
- MPT, mitochondrial permeability transition
- PAG, phosphate-activated glutaminase
- PTP, permeability transition pore
- TLR, toll-like receptor
- ammonia
- hepatic encephalopathy
- iNOS, inducible nitric oxide synthase
- infection
- inflammation
- systemic inflammatory response syndrome
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Affiliation(s)
| | | | - Debbie L. Shawcross
- Institute of Liver Studies, King's College London School of Medicine at King's College Hospital, King's College Hospital, Denmark Hill, London SE5 9RS, United Kingdom
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Saracyn M, Brytan M, Zdanowski R, Ząbkowski T, Dyrla P, Patera J, Wojtuń S, Kozłowski W, Wańkowicz Z. Hepatoprotective effect of nitric oxide in experimental model of acute hepatic failure. World J Gastroenterol 2014; 20:17407-17415. [PMID: 25516652 PMCID: PMC4265599 DOI: 10.3748/wjg.v20.i46.17407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 07/08/2014] [Accepted: 09/05/2014] [Indexed: 02/06/2023] Open
Abstract
AIM: To evaluate the effect of nitric oxide (NO) on the development and degree of liver failure in an animal model of acute hepatic failure (AHF).
METHODS: An experimental rat model of galactosamine-induced AHF was used. An inhibitor of NO synthase, nitroarginine methyl ester, or an NO donor, arginine, were administered at various doses prior to or after the induction of AHF.
RESULTS: All tested groups developed AHF. Following inhibition of the endogenous NO pathway, most liver parameters improved, regardless of the inhibitor dose before the induction of liver damage, and depending on the inhibitor dose after liver damage. Prophylactic administration of the inhibitor was more effective in improving liver function parameters than administration of the inhibitor after liver damage. An attempt to activate the endogenous NO pathway prior to the induction of liver damage did not change the observed liver function parameters. Stimulation of the endogenous NO pathway after liver damage, regardless of the NO donor dose used, improved most liver function parameters.
CONCLUSION: The endogenous NO pathway plays an important role in the development of experimental galactosamine-induced AHF.
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Yang JY, Xue X, Tian H, Wang XX, Dong YX, Wang F, Zhao YN, Yao XC, Cui W, Wu CF. Role of microglia in ethanol-induced neurodegenerative disease: Pathological and behavioral dysfunction at different developmental stages. Pharmacol Ther 2014; 144:321-37. [DOI: 10.1016/j.pharmthera.2014.07.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 07/03/2014] [Indexed: 01/04/2023]
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Abstract
Human adults produce around 1000 mmol of ammonia daily. Some is reutilized in biosynthesis. The remainder is waste and neurotoxic. Eventually most is excreted in urine as urea, together with ammonia used as a buffer. In extrahepatic tissues, ammonia is incorporated into nontoxic glutamine and released into blood. Large amounts are metabolized by the kidneys and small intestine. In the intestine, this yields ammonia, which is sequestered in portal blood and transported to the liver for ureagenesis, and citrulline, which is converted to arginine by the kidneys. The amazing developments in NMR imaging and spectroscopy and molecular biology have confirmed concepts derived from early studies in animals and cell cultures. The processes involved are exquisitely tuned. When they are faulty, ammonia accumulates. Severe acute hyperammonemia causes a rapidly progressive, often fatal, encephalopathy with brain edema. Chronic milder hyperammonemia causes a neuropsychiatric illness. Survivors of severe neonatal hyperammonemia have structural brain damage. Proposed explanations for brain edema are an increase in astrocyte osmolality, generally attributed to glutamine accumulation, and cytotoxic oxidative/nitrosative damage. However, ammonia neurotoxicity is multifactorial, with disturbances also in neurotransmitters, energy production, anaplerosis, cerebral blood flow, potassium, and sodium. Around 90% of hyperammonemic patients have liver disease. Inherited defects are rare. They are being recognized increasingly in adults. Deficiencies of urea cycle enzymes, citrin, and pyruvate carboxylase demonstrate the roles of isolated pathways in ammonia metabolism. Phenylbutyrate is used routinely to treat inherited urea cycle disorders, and its use for hepatic encephalopathy is under investigation.
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Affiliation(s)
- Valerie Walker
- Department of Clinical Biochemistry, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom.
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Comparative Neuroprotective Effects of Dexamethasone and Minocycline during Hepatic Encephalopathy. Neurol Res Int 2014; 2014:254683. [PMID: 24693424 PMCID: PMC3945529 DOI: 10.1155/2014/254683] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 12/08/2013] [Accepted: 12/26/2013] [Indexed: 01/30/2023] Open
Abstract
Objective. Encephalopathy and brain edema are serious complications of acute liver injury and may lead to rapid death of patients. The present study was designed to investigate the role of the inflammatory mediators and oxidative stress in the cytotoxic brain oedema and the neuroprotective effects of both minocycline and dexamethasone.
Methods. 48 male albino rats were divided into 4 groups: control group, acute liver injury (ALI) group, minocycline pretreated ALI group, and dexamethasone pretreated ALI group. 24 hours after acute liver injury serum ammonia, liver enzymes, brain levels of heme oxygenase-1 gene, iNOS gene expression, nitrite/nitrate, and cytokines were measured. In addition, the grades of encephalopathy and brain water content were assessed. Results. ALI was associated with significant increases in all measured inflammatory mediators, oxidative stress, iNOS gene expression, and nitrite/nitrate. Both minocycline and dexamethasone significantly modulated the inflammatory changes and the oxidative/nitrosative stress associated with ALI. However, only minocycline but not dexamethasone significantly reduced the cytotoxic brain oedema. Conclusion. Both minocycline and dexamethasone could modulate inflammatory and oxidative changes observed in brain after ALI and could be novel preventative therapy for hepatic encephalopathy episodes.
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Sturgeon JP, Shawcross DL. Recent insights into the pathogenesis of hepatic encephalopathy and treatments. Expert Rev Gastroenterol Hepatol 2014; 8:83-100. [PMID: 24236755 DOI: 10.1586/17474124.2014.858598] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Hepatic encephalopathy (HE) encompasses a spectrum of neuropsychiatric disorders related to liver failure. The development of HE can have a profound impact on mortality as well as quality of life for patients and carers. Ammonia is central in the disease process contributing to alteration in neurotransmission, oxidative stress, and cerebral edema and astrocyte swelling in acute liver failure. Inflammation in the presence of ammonia coactively worsens HE. Inflammation can result from hyperammonemic responses, endotoxemia, innate immune dysfunction or concurrent infection. This review summarizes the current processes implicated in the pathogenesis of HE, as well as current and potential treatments. Treatments currently focus on reducing inflammation and/or blood ammonia levels and provide varying degrees of success. Optimization of current treatments and initial testing of novel therapies will provide the basis of improvement of care in the near future.
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Affiliation(s)
- Jonathan P Sturgeon
- Institute of Liver Studies, King's College London School of Medicine at King's College Hospital, Denmark Hill, London, SE5 9RS, UK
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Scott TR, Kronsten VT, Hughes RD, Shawcross DL. Pathophysiology of cerebral oedema in acute liver failure. World J Gastroenterol 2013; 19:9240-9255. [PMID: 24409052 PMCID: PMC3882398 DOI: 10.3748/wjg.v19.i48.9240] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 10/28/2013] [Accepted: 11/19/2013] [Indexed: 02/06/2023] Open
Abstract
Cerebral oedema is a devastating consequence of acute liver failure (ALF) and may be associated with the development of intracranial hypertension and death. In ALF, some patients may develop cerebral oedema and increased intracranial pressure but progression to life-threatening intracranial hypertension is less frequent than previously described, complicating less than one third of cases who have proceeded to coma since the advent of improved clinical care. The rapid onset of encephalopathy may be dramatic with the development of asterixis, delirium, seizures and coma. Cytotoxic and vasogenic oedema mechanisms have been implicated with a preponderance of experimental data favouring a cytotoxic mechanism. Astrocyte swelling is the most consistent neuropathological finding in humans with ALF and ammonia plays a definitive role in the development of cytotoxic brain oedema. The mechanism(s) by which ammonia induces astrocyte swelling remains unclear but glutamine accumulation within astrocytes has led to the osmolyte hypothesis. Current evidence also supports an alternate ‘Trojan horse’ hypothesis, with glutamine as a carrier of ammonia into mitochondria, where its accumulation results in oxidative stress, energy failure and ultimately astrocyte swelling. Although a complete breakdown of the blood-brain barrier is not evident in human ALF, increased permeation to water and other small molecules such as ammonia has been demonstrated resulting from subtle alterations in the protein composition of paracellular tight junctions. At present, there is no fully efficacious therapy for cerebral oedema other than liver transplantation and this reflects our incomplete knowledge of the precise mechanisms underlying this process which remain largely unknown.
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Kumar A, Chaudhary T, Mishra J. Minocycline modulates neuroprotective effect of hesperidin against quinolinic acid induced Huntington's disease like symptoms in rats: behavioral, biochemical, cellular and histological evidences. Eur J Pharmacol 2013; 720:16-28. [PMID: 24211676 DOI: 10.1016/j.ejphar.2013.10.057] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 10/25/2013] [Accepted: 10/29/2013] [Indexed: 12/18/2022]
Abstract
Emerging evidences indicate hesperidin, a citrus flavanone, attenuates neurodegenerative processes and related complications. Besides its anti-oxidant properties, the other probable mechanisms which underpin its neuroprotective potential are still not clear. In light of emerging role of flavonoids in modulating oxidative stress and neuro-inflammation, the study has been designed to explore the possible neuroprotective effect of hesperidin and its combination with minocycline (microglial inhibitor), against quinolinic acid (QA) induced Huntington's disease (HD) like symptoms in rats. Unilateral intrastriatal administration of QA (300 nmol/4 µl) significantly reduced body weight, impaired behavior (locomotor activity, beam balance and memory performance), caused oxidative damage (increased lipid peroxidation, nitrite concentration, depleted super oxide dismutase and reduced glutathione), demonstrated mitochondrial dysfunction (decreased Complex-I, II, III, and IV activities), increased striatal lesion volume and altered the levels of TNF-α, caspase-3 as well as BDNF expression, as compared to sham group. Meanwhile, chronic hesperidin (100mg/kg, p.o.) and minocycline (25mg/kg, p.o.) treatment for 21 days significantly attenuated the behavioral, biochemical and cellular alterations as compared to QA treated (control) animals, whereas hesperidin (50mg/kg, p.o.) treatment was found to be non-significant. However, treatment of hesperidin (50mg/kg) in combination with minocycline (25mg/kg) potentiated their neuroprotective effect, which was significant as compared to their effects per se in QA treated animals. Taken altogether, the results of the present study suggest a possible interplay of microglial modulation and anti-oxidant effect in neuroprotective potential of hesperidin against QA induced HD like symptoms in rats.
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Affiliation(s)
- Anil Kumar
- Pharmacology Division, University Institute of Pharmaceutical Sciences, UGC-Centre of Advanced Study (UGC-CAS), Panjab University, Chandigarh 160014, India.
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Abstract
Systemic inflammation is common in liver failure and its acquisition is a predictor of hepatic encephalopathy severity. New studies provide convincing evidence for a role of neuroinflammation (inflammation of the brain per se) in liver failure; this evidence includes activation of microglia, together with increased synthesis in situ of the proinflammatory cytokines TNF, IL-1β and IL-6. Liver-brain signalling mechanisms in liver failure include: direct effects of systemic proinflammatory molecules, recruitment of monocytes after microglial activation, brain accumulation of ammonia, lactate and manganese, and altered permeability of the blood-brain barrier. Ammonia and cytokines might act synergistically. Existing strategies to reduce ammonia levels (including lactulose, rifaximin and probiotics) have the potential to dampen systemic inflammation, as does albumin dialysis, mild hypothermia and N-acetylcysteine, the latter two agents acting at both peripheral and central sites. Minocycline, an agent with potent central anti-inflammatory properties, reduces neuroinflammation, brain oedema and encephalopathy in liver failure, as does the anti-TNF agent etanercept.
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Wang QM, Yin XY, Duan ZJ, Guo SB, Sun XY. Role of the heme oxygenase/carbon monoxide pathway in the pathogenesis and prevention of hepatic encephalopathy. Mol Med Rep 2013; 8:67-74. [PMID: 23670786 DOI: 10.3892/mmr.2013.1472] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 04/29/2013] [Indexed: 11/05/2022] Open
Abstract
Hepatic encephalopathy (HE) is a severe complication of liver cirrhosis and its pathogenesis has yet to be fully elucidated. Previous studies have demonstrated that heme oxygenase-1 (HO-1) is important in the induction of liver cirrhosis. The present study aimed to investigate the role of HO-1 in the pathogenesis of HE. Rats were divided into 5 treatment groups; sham, bile duct ligation (BDL), HE, zinc protoporphyrin (ZnPP) and cobalt protoporphyrin (CoPP). The levels of HO-1 were examined by western blotting and quantitative real-time PCR (qRT-PCR). Serum levels of carboxyhemoglobin (COHb), ammonia levels in the plasma and brain, brain water content and portal vein pressure (PVP) were also quantified. Aquaporin-4 expression levels were measured by immunohistochemistry and qRT-PCR. The results demonstrated that the levels of HO-1 in the brain and the serum levels of COHb were significantly increased in the HE group compared with the BDL group. Brain water content, PVP and ammonia levels in the plasma and brain were increased in the HE and CoPP groups; however, these were reduced following the treatment with ZnPP. The levels of AQP-4 expression and oxidative stress in the brain were reduced following treatment with ZnPP and increased following treatment with CoPP. In conclusion, following the inhibition of HO-1 expression, treatment with ZnPP improved HE due to reducing the expression levels of AQP-4 and oxidative stress. Therefore, ZnPP treatment may represent a novel therapeutic approach for HE.
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Affiliation(s)
- Qiu-Ming Wang
- Department of Gastroenterology, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116011, PR China
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Coltart I, Tranah TH, Shawcross DL. Inflammation and hepatic encephalopathy. Arch Biochem Biophys 2013; 536:189-96. [PMID: 23583306 DOI: 10.1016/j.abb.2013.03.016] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 03/13/2013] [Accepted: 03/19/2013] [Indexed: 12/12/2022]
Abstract
Hepatic encephalopathy (HE) is a neuropsychiatric syndrome associated with both acute and chronic liver dysfunction, spanning a spectrum that ranges from mild neuropsychological disturbances to coma. The central role of ammonia in the pathogenesis of HE remains incontrovertible however, there is a robust evidence base indicating the important role of inflammation in exacerbating the neurological effects of HE. Inflammation can arise directly within the brain itself as a result of deranged nitrogen and energy homeostasis, with resultant neuronal, astrocyte and microglial dysfunction. Inflammation may also originate in the peripheral circulation and exert effects on the brain indirectly, via the release of pro-inflammatory mediators which directly signal to the brain via the vagus nerve. This review summarises the data that demonstrate the synergistic relationship of inflammation and ammonia that culminates in the manifestation of HE. Sterile inflammation arising from the inflamed or necrotic liver, circulating endotoxin arising from the gut (bacterial translocation) inducing immune dysfunction, and superimposed sepsis will be comprehensively discussed. Finally, this review will provide an overview of the existing and novel treatments on the horizon which can target the inflammatory response, and how they might translate into clinical practise as therapies in the prophylaxis and treatment of HE.
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Affiliation(s)
- Iona Coltart
- Institute of Liver Studies, King's College London School of Medicine at King's College Hospital, King's College Hospital, Denmark Hill, London SE5 9RS, United Kingdom
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Abstract
Acute hepatic failure (AHF) is a devastating clinical syndrome characterized by rapid impairment of liver functions and development of encephalopathy, multiple organ failure, and in most cases cerebral edema. AHF has a high mortality rate. Although advances in drug treatment, artificial liver and liver transplantation have significantly improved the prognosis of AHF, there is still a lack of effective treatment for AHF because of its complicated etiopathogenesis, rapid progression and less clinical knowledge about managing the disease. There is an urgent need to develop effective treatments for AHF. This article aims to review recent advances in the treatment of AHF.
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Skowrońska M, Albrecht J. Oxidative and nitrosative stress in ammonia neurotoxicity. Neurochem Int 2012; 62:731-7. [PMID: 23142151 DOI: 10.1016/j.neuint.2012.10.013] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Revised: 10/18/2012] [Accepted: 10/28/2012] [Indexed: 12/16/2022]
Abstract
Increased ammonia accumulation in the brain due to liver dysfunction is a major contributor to the pathogenesis of hepatic encephalopathy (HE). Fatal outcome of rapidly progressing (acute) HE is mainly related to cytotoxic brain edema associated with astrocytic swelling. An increase of brain ammonia in experimental animals or treatment of cultured astrocytes with ammonia generates reactive oxygen and nitrogen species in the target tissues, leading to oxidative/nitrosative stress (ONS). In cultured astrocytes, ammonia-induced ONS is invariably associated with the increase of the astrocytic cell volume. Interrelated mechanisms underlying this response include increased nitric oxide (NO) synthesis which is partly coupled to the activation of NMDA receptors and increased generation of reactive oxygen species by NADPH oxidase. ONS and astrocytic swelling are further augmented by excessive synthesis of glutamine (Gln) which impairs mitochondrial function following its accumulation in there and degradation back to ammonia ("the Trojan horse" hypothesis). Ammonia also induces ONS in other cell types of the CNS: neurons, microglia and the brain capillary endothelial cells (BCEC). ONS in microglia contributes to the central inflammatory response, while its metabolic and pathophysiological consequences in the BCEC evolve to the vasogenic brain edema associated with HE. Ammonia-induced ONS results in the oxidation of mRNA and nitration/nitrosylation of proteins which impact intracellular metabolism and potentiate the neurotoxic effects. Simultaneously, ammonia facilitates the antioxidant response of the brain, by activating astrocytic transport and export of glutathione, in this way increasing the availability of precursors of neuronal glutathione synthesis.
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Affiliation(s)
- Marta Skowrońska
- Department of Neurotoxicology, Mossakowski Medical Research Center, Polish Academy of Sciences, Pawinskiego 5, 02-106 Warsaw, Poland.
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Occludin dislocation in brain capillary endothelium of rats with bile duct ligation induced cholestasis. Neurosci Lett 2012; 528:180-4. [PMID: 22985504 DOI: 10.1016/j.neulet.2012.08.066] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 07/26/2012] [Accepted: 08/09/2012] [Indexed: 01/24/2023]
Abstract
The present study used a rat model with bile duct ligation to examine the effect of cholestasis, to the localization of occludin in brain capillary endothelium by means of electronic microscopy. The results demonstrated a dislocation of occludin away from the tight junction sites of brain endothelial cells. A significant increase of the occludin-interendothelial cleft distance was demonstrated in the midbrain and the cerebellum samples but not in the frontal cortex, compared to the control group samples. These findings imply a brain region selective derangement of occludin in response to liver disease.
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Rangroo Thrane V, Thrane AS, Chang J, Alleluia V, Nagelhus EA, Nedergaard M. Real-time analysis of microglial activation and motility in hepatic and hyperammonemic encephalopathy. Neuroscience 2012; 220:247-55. [PMID: 22728097 DOI: 10.1016/j.neuroscience.2012.06.022] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 06/05/2012] [Accepted: 06/07/2012] [Indexed: 11/20/2022]
Abstract
Hepatic encephalopathy (HE) is a potentially fatal complication of acute liver failure, associated with severe neurological dysfunction and coma. The brain's innate immune cells, microglia, have recently been implicated in the pathophysiology of HE. To date, however, only ex vivo studies have been used to characterize microglial involvement. Our study uses in vivo two-photon imaging of awake-behaving mice expressing enhanced green fluorescent protein (eGFP) under the Cx3cr1 promoter to examine microglial involvement in two different models of encephalopathy - a slower, fatal model of azoxymethane-induced HE and a rapid, reversible acute hyperammonemic encephalopathy (AHE) induced by an ammonia load. To investigate the potential contribution of microglia to the neurological deterioration seen in these two models, we developed a software to analyze microglial activation and motility in vivo. In HE, we found that microglia do not become activated prior to the onset of neurological dysfunction, but undergo activation with mildly impaired motility during the terminal stage IV. We demonstrate that this microglial activation coincides with blood-brain barrier (BBB) opening and brain edema. Conversely, both microglial activation and motility are unchanged during AHE, despite the mice developing pathologically increased plasma ammonia and severe neurological dysfunction. Our study indicates that microglial activation does not contribute to the early neurological deterioration observed in either HE or AHE. The late microglial activation in HE may therefore be associated with terminal BBB opening and brain edema, thus exacerbating the progression to coma and increasing mortality.
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Affiliation(s)
- V Rangroo Thrane
- Division of Glia Disease and Therapeutics, Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA.
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Kalonia H, Mishra J, Kumar A. Targeting Neuro-Inflammatory Cytokines and Oxidative Stress by Minocycline Attenuates Quinolinic-Acid-Induced Huntington’s Disease-Like Symptoms in Rats. Neurotox Res 2012; 22:310-20. [DOI: 10.1007/s12640-012-9315-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 02/17/2012] [Accepted: 02/18/2012] [Indexed: 01/23/2023]
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Mpabanzi L, Jalan R. Neurological complications of acute liver failure: pathophysiological basis of current management and emerging therapies. Neurochem Int 2011; 60:736-42. [PMID: 22100567 DOI: 10.1016/j.neuint.2011.10.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Revised: 10/17/2011] [Accepted: 10/26/2011] [Indexed: 12/11/2022]
Abstract
One of the major causes of mortality in patients with acute liver failure (ALF) is the development of hepatic encephalopathy (HE) which is associated with increased intracranial pressure (ICP). High ammonia levels, increased cerebral blood flow and increased inflammatory response have been identified as major contributors to the development of HE and the related brain swelling. The general principles of the management of patients with ALF are straightforward. They include identifying the insult causing hepatic injury, providing organ systems support to optimize the patient's physical condition, anticipation and prevention of development of complications. Increasing insights into the pathophysiological mechanisms of ALF are contributing to better therapies. For instance, the evident role of cerebral hyperemia in the pathogenesis of increased ICP has led to a re-evaluation of established therapies such as hyperventilation, N-acetylcysteine, thiopentone sodium and propofol. The role of systemic inflammatory response in the pathogenesis of increased ICP has also gained importance supporting the concept that antibiotics given prophylactically reduce the risk of developing sepsis during the course of illness. Moderate hypothermia has also been established as a therapy able to reduce ICP in patients with uncontrolled intracranial hypertension and to prevent increases in ICP during orthopic liver transplantation. Ornithine phenylacetate, a new drug in the treatment of liver failure, and liver replacement therapies are still being investigated both experimentally and clinically. Despite many advances in the understanding of the pathophysiological basis and the management of intracranial hypertension in ALF, more clinical trials should be conducted to determine the best therapeutic management for this difficult clinical event.
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Affiliation(s)
- Liliane Mpabanzi
- Department of Surgery, Maastricht University Medical Centre, and NUTRIM School of Nutrition, Toxicology and Metabolism, Maastricht University, PO Box 5800, Maastricht, The Netherlands
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Chang CC, Wang SS, Huang HC, Chan CY, Lee FY, Lin HC, Nong JY, Chuang CL, Lee SD. Selective cyclooxygenase inhibition improves hepatic encephalopathy in fulminant hepatic failure of rat. Eur J Pharmacol 2011; 666:226-32. [DOI: 10.1016/j.ejphar.2011.04.060] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Revised: 04/15/2011] [Accepted: 04/18/2011] [Indexed: 01/01/2023]
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Montoliu C, Cauli O, Urios A, ElMlili N, Serra MA, Giner-Duran R, González-Lopez O, Del Olmo JA, Wassel A, Rodrigo JM, Felipo V. 3-nitro-tyrosine as a peripheral biomarker of minimal hepatic encephalopathy in patients with liver cirrhosis. Am J Gastroenterol 2011; 106:1629-37. [PMID: 21483460 DOI: 10.1038/ajg.2011.123] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVES Between 30 and 50% of the cirrhotic patients who do not show symptoms of clinical hepatic encephalopathy (HE) present minimal hepatic encephalopathy (MHE), with mild cognitive impairment. MHE impairs the quality of life, increases the risk of suffering accidents, predicts the appearance of clinical HE, and is associated with shortened lifespan. Early detection of MHE would be very useful. The "gold standard" for MHE diagnosis is the psychometric hepatic encephalopathy score (PHES). However, it is time consuming and needs adjusting for age and educational level. It would be very useful to have some blood biomarker reflecting the presence of MHE in cirrhotic patients. The aim of this work was to identify serum molecules useful as biomarkers for MHE. METHODS We measured in 63 controls, 43 cirrhotic patients without MHE, and 44 patients with MHE, from Hospital Clinico de Valencia, serum levels of different amino acids, cyclic guanosine monophosphate (cGMP), nitrites+nitrates, and 3-nitrotyrosine. We analyzed for each parameter its diagnostic accuracy as an indicator of MHE, as assessed using the PHES. RESULTS These studies supported that 3-nitro-tyrosine is a good marker for MHE. To validate its utility as a biomarker for MHE, we analyzed in a second cohort of 44 cirrhotic patients without MHE and 18 patients with MHE, from Hospital Arnau de Vilanova, serum levels of 3-nitro-tyrosine, methionine, and citrulline. Citrulline (173±17%), methionine (173±16%), and 3-nitro-tyrosine (857±92%) were increased in sera from patients with MHE when compared with those without MHE. The receiver operating characteristic (ROC) curve analysis of 3-nitro-tyrosine for the diagnosis of MHE in the first cohort showed an area under the curve (AUC) value of 0.96 (95% confidence interval 0.93-0.99). At the cutoff of 14 nM, the specificity was 93%, sensitivity 89%, and positive and negative predictive values were both 91%. When the same cutoff was applied to the second cohort, the specificity was 83% and sensitivity was 94%. The positive and negative predictive values were 70 and 97%, respectively. CONCLUSIONS This pilot study, to be validated in a larger cohort, shows that determination of 3-nitro-tyrosine in serum, which is easy and not time consuming, is useful to identify patients with MHE, with good sensitivity, specificity, and positive and negative predictive values.
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Affiliation(s)
- Carmina Montoliu
- Fundación Investigación Hospital Clínico Universitario de Valencia, INCLIVA, Valencia, Spain
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Liu Y, Qiang M, Wei Y, He R. A novel molecular mechanism for nitrated {alpha}-synuclein-induced cell death. J Mol Cell Biol 2011; 3:239-49. [PMID: 21733982 DOI: 10.1093/jmcb/mjr011] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Although previous studies have demonstrated the involvement of nitrated α-synuclein in neurodegenerative disorders (synucleinopathies), the effects of nitrated α-synuclein and the molecular mechanisms underlying its toxicity are still unclear. In the present study, nitrated α-synuclein with four 3-nitrotyrosines (Tyr(39), Tyr(125), Tyr(133), and Tyr(136)) was obtained non-enzymatically by incubation with nitrite. The nitrated protein existed as a mixture of monomers, dimers, and polymers in solution. The nitrated α-synuclein could induce cell death in a time- and concentration-dependent manner when SH-SY5Y cells (a human neuroblastoma cell line) were incubated with the dimers and polymers. Treatment with anti-integrin α5β1 antibody partially rescued the SH-SY5Y cells from the cell death. Dot blotting and immunoprecipitation revealed that the nitrated protein bound to integrin on the cell membranes. Level of nitric oxide (NO) and calcium-independent inducible NO synthase (iNOS) activity increased during the initial stages of the treatment. The expression of phosphorylated focal adhesion kinase (FAK) decreased in the cells. Subsequently, an increase in caspase 3 activity was observed in SH-SY5Y cells. Our results demonstrate that activation of iNOS and inhibition of FAK may both be responsible for the cell death induced by nitrated α-synuclein. These data suggest that the cytotoxicity of nitrated α-synuclein is mediated via an integrin-iNOS/-FAK signaling pathway, and that the nitration of α-synuclein plays a role in neuronal degeneration.
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Affiliation(s)
- Yanying Liu
- State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
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Zemtsova I, Görg B, Keitel V, Bidmon HJ, Schrör K, Häussinger D. Microglia activation in hepatic encephalopathy in rats and humans. Hepatology 2011; 54:204-15. [PMID: 21452284 DOI: 10.1002/hep.24326] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
UNLABELLED Astrocytes play an important role in the pathogenesis of hepatic encephalopathy (HE) and ammonia toxicity, whereas little is known about microglia and neuroinflammation under these conditions. We therefore studied the effects of ammonia on rat microglia in vitro and in vivo and analyzed markers of neuroinflammation in post mortem brain tissue from patients with cirrhosis with and without HE and non-cirrhotic controls. In cultured rat microglia, ammonia stimulated cell migration and induced oxidative stress and an up-regulation of the microglial activation marker ionized calcium-binding adaptor molecule-1 (Iba-1). Up-regulation of Iba-1 was also found in the cerebral cortex from acutely ammonia-intoxicated rats and in the cerebral cortex from patients with cirrhosis who have HE, but not from patients with cirrhosis who do not have HE. However, ammonia had no effect on microglial glutamate release, prostaglandin synthesis, and messenger RNA (mRNA) levels of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and the proinflammatory cytokines interleukin (IL)-1α/β, tumor necrosis factor α, or IL-6, whereas in cultured astrocytes ammonia induced the release of glutamate, prostaglandins, and increased IL-1β mRNA. mRNA and protein expression of iNOS and COX-2 or mRNA expression of proinflammatory cytokines and chemokine monocyte chemoattractive protein-1 in cerebral cortex from patients with liver cirrhosis and HE were not different from those found in patients with cirrhosis who did not have HE or control patients without cirrhosis. CONCLUSION These data suggest that microglia become activated in experimental hyperammonemia and HE in humans and may contribute to the generation of oxidative stress. However, HE in patients with liver cirrhosis is not associated with an up-regulation of inflammatory cytokines in cerebral cortex, despite microglia activation.
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Affiliation(s)
- Irina Zemtsova
- Clinic for Gastroenterology, Hepatology, and Infectiology, Heinrich-Heine University, Düsseldorf, Germany
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Sidoryk-Wegrzynowicz M, Wegrzynowicz M, Lee E, Bowman AB, Aschner M. Role of astrocytes in brain function and disease. Toxicol Pathol 2010; 39:115-23. [PMID: 21075920 DOI: 10.1177/0192623310385254] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Astrocytes assume multiple roles in maintaining an optimally suited milieu for neuronal function. Select astrocytic functions include the maintenance of redox potential, the production of trophic factors, the regulation of neurotransmitter and ion concentrations, and the removal of toxins and debris from the cerebrospinal fluid (CSF). Impairments in these and other functions, as well as physiological reactions of astrocytes to injury, can trigger or exacerbate neuronal dysfunction. This review addresses select metabolic interactions between neurons and astrocytes and emphasizes the role of astrocytes in mediating and amplifying the progression of several neurodegenerative disorders, such as Parkinson's disease (PD), hepatic encephalopathy (HE), hyperammonemia (HA), Alzheimer's disease (AD), and ischemia.
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Seyan AS, Hughes RD, Shawcross DL. Changing face of hepatic encephalopathy: Role of inflammation and oxidative stress. World J Gastroenterol 2010; 16:3347-57. [PMID: 20632436 PMCID: PMC2904880 DOI: 10.3748/wjg.v16.i27.3347] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The face of hepatic encephalopathy (HE) is changing. This review explores how this neurocognitive disorder, which is associated with both acute and chronic liver injury, has grown to become a dynamic syndrome that spans a spectrum of neuropsychological impairment, from normal performance to coma. The central role of ammonia in the pathogenesis of HE remains incontrovertible. However, over the past 10 years, the HE community has begun to characterise the key roles of inflammation, infection, and oxidative/nitrosative stress in modulating the pathophysiological effects of ammonia on the astrocyte. This review explores the current thoughts and evidence base in this area and discusses the potential role of existing and novel therapies that might abrogate the oxidative and nitrosative stresses inflicted on the brain in patients with, or at risk of developing, HE.
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Bemeur C, Desjardins P, Butterworth RF. Evidence for oxidative/nitrosative stress in the pathogenesis of hepatic encephalopathy. Metab Brain Dis 2010; 25:3-9. [PMID: 20195724 DOI: 10.1007/s11011-010-9177-y] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Accepted: 09/22/2009] [Indexed: 12/11/2022]
Abstract
Hepatic encephalopathy (HE) is a serious complication of liver failure. HE manifests as a series of neuropsychiatric and neuromuscular symptoms including personality changes, sleep abnormalities, asterixis and muscle rigidity progressing through stupor to coma. The pathophysiologic basis of HE remains unclear. There is general agreement that ammonia plays a key role. In recent years, it has been suggested that oxidative/nitrosative stress constitutes part of the pathophysiologic cascade in HE. Direct evidence for oxidative/nitrosative stress in the pathogenesis of HE has been demonstrated in experimental animal models of acute or chronic liver failure. However, evidence from studies in HE patients is limited. This review summarizes this evidence for a role of oxidative/nitrosative stress in relation to ammonia toxicity and to the pathogenesis of HE.
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Affiliation(s)
- Chantal Bemeur
- Neuroscience Research Unit, Hôpital Saint-Luc (CHUM) University of Montreal, Montreal, QC, Canada
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Chastre A, Jiang W, Desjardins P, Butterworth RF. Ammonia and proinflammatory cytokines modify expression of genes coding for astrocytic proteins implicated in brain edema in acute liver failure. Metab Brain Dis 2010; 25:17-21. [PMID: 20217200 DOI: 10.1007/s11011-010-9185-y] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2009] [Accepted: 01/20/2010] [Indexed: 10/19/2022]
Abstract
There is evidence to suggest that, in acute liver failure (ALF), brain ammonia and proinflammatory cytokines may act synergistically to cause brain edema and its complications (intracranial hypertension, brain herniation). However, the molecular mechanisms involved remain to be established. In order to address this issue, semi-quantitative RT-PCR was used to measure the expression of genes coding for astrocytic proteins with an established role in cell volume regulation in cerebral cortical astrocytes exposed to toxic agents previously identified in experimental and clinical ALF. Such agents include ammonia, the proinflammatory cytokine interleukin-1beta (IL-1beta) and combinations of the two. Exposure of cultured astrocytes to recombinant IL-1beta (but not ammonia) resulted in increased expression of aquaporin-4 (AQP-4). Both ammonia and proinflammatory mediators led to decreased expression of glial fibrillary acidic protein (GFAP), a cytoskeletal protein, but these effects were not additive. On the other hand, heme oxygenase-1 (HO-1) and inducible nitric oxide synthase (iNOS) expression were significantly increased by exposure to both ammonia and proinflammatory mediators and although modest, these effects were additive suggestive of a synergistic mechanism. These findings suggest that worsening of brain edema and its complications in ALF due to proinflammatory mechanisms may result from exacerbation of oxidative stress-related mechanisms rather than upregulation of AQP-4 or decreases in expression of the astrocytic structural protein GFAP.
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Affiliation(s)
- Anne Chastre
- Neuroscience Research Unit, St-Luc Hospital (CHUM), University of Montreal, Montreal, Quebec, Canada
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Rama Rao KV, Reddy PVB, Tong X, Norenberg MD. Brain edema in acute liver failure: inhibition by L-histidine. THE AMERICAN JOURNAL OF PATHOLOGY 2010; 176:1400-8. [PMID: 20075201 DOI: 10.2353/ajpath.2010.090756] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Brain edema and the associated increase in intracranial pressure are potentially lethal complications of acute liver failure (ALF). Astrocyte swelling (cytotoxic edema) represents a significant component of the brain edema in ALF, and elevated blood and brain ammonia levels have been strongly implicated in its formation. We earlier showed in cultured astrocytes that oxidative stress (OS) and the mitochondrial permeability transition (mPT) play major roles in the mechanism of ammonia-induced astrocyte swelling. Glutamine, a byproduct of ammonia metabolism, has also been shown to induce OS, the mPT, and astrocyte swelling. Such effects of glutamine were suggested to be mediated by its hydrolysis in mitochondria, potentially yielding high levels of ammonia in this organelle and leading to OS and the mPT. L-histidine, an inhibitor of mitochondrial glutamine transport, was recently shown to mitigate OS, mPT, and cell swelling in cultured astrocytes treated with ammonia. The present study examined whether L-histidine similarly abolishes OS, the mPT, and brain edema in a rat model of ALF. Treatment of rats with thioacetamide caused a significant degree of brain edema, which was associated with induction of OS and the mPT. These changes were completely abolished by L-histidine, supporting a key role of mitochondrial glutamine transport and hydrolysis in the mechanism of 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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