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Nakadate K, Sono C, Mita H, Itakura Y, Kawakami K. Severe Acute Liver Dysfunction Induces Delayed Hepatocyte Swelling and Cytoplasmic Vacuolization, and Delayed Cortical Neuronal Cell Death. Int J Mol Sci 2023; 24:ijms24087351. [PMID: 37108515 PMCID: PMC10139143 DOI: 10.3390/ijms24087351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 04/10/2023] [Accepted: 04/14/2023] [Indexed: 04/29/2023] Open
Abstract
Liver dysfunction is the main cause of hepatic encephalopathy. However, histopathological changes in the brain associated with hepatic encephalopathy remain unclear. Therefore, we investigated pathological changes in the liver and brain using an acute hepatic encephalopathy mouse model. After administering ammonium acetate, a transient increase in the blood ammonia level was observed, which returned to normal levels after 24 h. Consciousness and motor levels also returned to normal. It was revealed that hepatocyte swelling, and cytoplasmic vacuolization progressed over time in the liver tissue. Blood biochemistry also suggested hepatocyte dysfunction. In the brain, histopathological changes, such as perivascular astrocyte swelling, were observed 3 h after ammonium acetate administration. Abnormalities in neuronal organelles, especially mitochondria and rough endoplasmic reticulum, were also observed. Additionally, neuronal cell death was observed 24 h post-ammonia treatment when blood ammonia levels had returned to normal. Activation of reactive microglia and increased expression of inducible nitric oxide synthase (iNOS) were also observed seven days after a transient increase in blood ammonia. These results suggest that delayed neuronal atrophy could be iNOS-mediated cell death due to activation of reactive microglia. The findings also suggest that severe acute hepatic encephalopathy causes continued delayed brain cytotoxicity even after consciousness recovery.
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Affiliation(s)
- Kazuhiko Nakadate
- Department of Basic Science, Educational and Research Center for Pharmacy, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose 204-8588, Tokyo, Japan
| | - Chiaki Sono
- Department of Basic Science, Educational and Research Center for Pharmacy, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose 204-8588, Tokyo, Japan
| | - Homura Mita
- Department of Basic Science, Educational and Research Center for Pharmacy, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose 204-8588, Tokyo, Japan
| | - Yuki Itakura
- Department of Basic Science, Educational and Research Center for Pharmacy, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose 204-8588, Tokyo, Japan
| | - Kiyoharu Kawakami
- Department of Basic Science, Educational and Research Center for Pharmacy, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose 204-8588, Tokyo, Japan
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2
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Jiang SX, Hussaini T, Yoshida EM. N-acetylcysteine for non-acetaminophen induced acute liver failure: A review. Saudi J Gastroenterol 2022; 28:85-91. [PMID: 35142656 PMCID: PMC9007071 DOI: 10.4103/sjg.sjg_406_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The use of N-acetylcysteine (NAC) for non-acetaminophen-induced acute liver failure (NAI-ALF) has been increasing despite controversy in its efficacy. National guidelines are in disagreement for NAC use as standard of care; however, many healthcare centers continue to adopt the use of NAC outside of acetaminophen poisoning. While NAC may have multiple mechanisms of action in treatment of ALF, this has not translated to clinical benefit. Murine models have reported antioxidant and anti-inflammatory properties, as well as improvement in liver-specific microcirculation. Multiple case studies and series have reported positive outcomes of NAC treatment for ALF of various etiologies. While prospective studies suggested the benefit of NAC treatment, these studies have methodological and statistical shortcomings that affect the validity of the results. In this review, we aimed to summarize the existing literature on the efficacy of NAC for NAI-ALF including mechanism of action, case studies and series demonstrating outcomes, and prospective studies that have led to its current widespread use, along with the reported rate of adverse events.
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Affiliation(s)
- Shirley Xue Jiang
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Trana Hussaini
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Eric M. Yoshida
- Division of Gastroenterology, University of British Columbia, Vancouver General Hospital, Vancouver, BC, Canada,Address for correspondence: Dr. Eric M. Yoshida, Division of Gastroenterology, Faculty of Medicine, 5th Floor-2775 Laurel St., Vancouver, BC, Canada. E-mail:
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3
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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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4
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Efficacy and safety of N-acetylcysteine for the treatment of non-acetaminophen-induced acute liver failure: an updated systematic review and meta-analysis. Clin Exp Hepatol 2021; 7:156-164. [PMID: 34295982 PMCID: PMC8284175 DOI: 10.5114/ceh.2021.107171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Accepted: 01/26/2021] [Indexed: 11/17/2022] Open
Abstract
Aim of the study N-acetylcysteine (NAC) is the treatment of choice for acetaminophen-induced liver injury. However, recent years have witnessed growing interest in its role in the treatment of acute liver failure (ALF) due to other aetiologies. This study aims to determine both its safety and efficacy by pooling data from multiple studies. Material and methods A search was conducted for all controlled randomized/non-randomized studies that measured the efficacy and safety of NAC in adult patients with non-acetaminophen-induced acute liver failure (NAI-ALF). Transplant-free survival (TFS) was considered the primary endpoint, while secondary endpoints such as length of hospital stay, and incidence of adverse events during treatment, were included in our analysis. Data were pooled via a random-effects model, I2 was used as a measure of heterogeneity, and publication bias was assessed via a funnel plot. Results A total of 3 studies [2 randomized controlled trials (RCTs) and 1 non-randomized cohort] were pooled in this meta-analysis. TFS was significantly higher in patients given NAC, when compared to the placebo/control (PBO) group (RR = 1.54, CI = 1.19-1.98, p = 0.01, I2 = 0.0%). No secondary endpoint was observed to have improved significantly in patients prescribed NAC: length of hospital stay (SMD = –0.405, CI = –1.44-0.63, p = 0.445, I2 = 91.1%), renal failure (RR = 1.01, CI = 0.65-1.57, p = 0.967, I2 = 21.3%), infections (RR = 1.18, CI = 0.91-1.52, p = 0.208, I2 = 2.3%), pulmonary failure (RR = 1.19, CI = 0.57-2.49, p = 0.649, I2 = 84.6%). Minimal side effects were reported in around 10-14% of the patients prescribed NAC. Conclusions NAC was shown to significantly improve TFS in adult patients with NAI-ALF, while no significant benefit was observed concerning the secondary endpoints of length of hospital stay and incidence of adverse effects.
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Sepehrinezhad A, Shahbazi A, Sahab Negah S, Joghataei MT, Larsen FS. Drug-induced-acute liver failure: A critical appraisal of the thioacetamide model for the study of hepatic encephalopathy. Toxicol Rep 2021; 8:962-970. [PMID: 34026559 PMCID: PMC8122178 DOI: 10.1016/j.toxrep.2021.04.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 04/17/2021] [Accepted: 04/27/2021] [Indexed: 12/12/2022] Open
Abstract
Hepatic encephalopathy (HE) following acute and chronic liver failure is defined as a complex of neuropsychiatric abnormalities, such as discrete personal changes, sleep disorder, forgetfulness, confusion, and decreasing the level of consciousness to coma. The use and design of suitable animal models that represent clinical features and pathological changes of HE are valuable to map the molecular mechanisms that result in HE. Among different types of animal models, thioacetamide (TAA) has been used extensively for the induction of acute liver injury and HE. This agent is not directly hepatotoxic but its metabolites induce liver injury through the induction of oxidative stress and produce systemic inflammation similar to that seen in acute HE patients. In this short review article, we shortly review the most important pathological findings in animal models of acute HE following the administration of TAA.
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Key Words
- ALT, alanine aminotransferase
- AQP4, aquaporin 4 water channel
- AST, aspartate aminotransferase
- Acute liver failure
- Animal model
- B7, B7 molecules (CD80+CD86)
- BBB, blood-brain barrier
- CBF, cerebral blood flow
- CCL2, chemokine ligand 2
- CNS, central nervous system
- CTLA4, Cytotoxic T-lymphocyte-associated Protein 4
- CYP2E1, Cytochrome P450 family 2 subfamily E member 1
- GFAP, glial fibrillary acidic protein
- HE, hepatic encephalopathy
- Hepatic encephalopathy
- IL-6, interleukin 6
- IL-β, interleukin 1 β
- Iba1, ionized calcium-binding adaptor molecule 1
- JNK, c-Jun N-terminal kinase
- NAC, N-acetylcysteine
- NF-κB, nuclear factor κB
- OA, L-ornithine-l-aspartate
- ROS, reactive oxygen species
- TAA, thioacetamide
- TASO, thioacetamide sulfoxide
- TASO2, thioacetamide sulfdioxide
- TLR-2, toll-like receptor 2
- TLR-4, toll-like receptor 4
- TNFα, tumor necrosis factor α
- Thioacetamide
- Toxicity pathway
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Affiliation(s)
- Ali Sepehrinezhad
- Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Iran
- Neuroscience Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Ali Shahbazi
- Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Iran
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Sajad Sahab Negah
- Neuroscience Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
- Shefa Neuroscience Research Center, Khatam Alanbia Hospital, Tehran, Iran
- Department of Neuroscience, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohammad Taghi Joghataei
- Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Iran
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Fin Stolze Larsen
- Department of Hepatology CA-3163, Rigshospitalet, Copenhagen University Hospital, Blegdamsvej 9, 2100, Copenhagen, Denmark
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Farshad O, Keshavarz P, Heidari R, Farahmandnejad M, Azhdari S, Jamshidzadeh A. The Potential Neuroprotective Role of Citicoline in Hepatic Encephalopathy. J Exp Pharmacol 2020; 12:517-527. [PMID: 33235522 PMCID: PMC7678475 DOI: 10.2147/jep.s261986] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Accepted: 11/03/2020] [Indexed: 12/29/2022] Open
Abstract
Purpose Hepatic encephalopathy (HE) is described as impaired brain function induced by liver failure. Ammonia is the most suspected chemical involved in brain injury during HE. Although the precise mechanism of HE is not clear, several studies mentioned the role of oxidative stress in ammonia neurotoxicity. In animal models, the use of some compounds with antioxidant properties was reported to reduce the neurotoxic effects of ammonia, improve energy metabolism, and ameliorate the HE symptoms. Citicoline is a principal intermediate in the biosynthesis pathway of phosphatidylcholine that acts as neurovascular protection and repair effects. Various studies mentioned the neuroprotective and antioxidative effects of citicoline in the central nervous system. This study aims to investigate the potential protective effects of citicoline therapeutic in an animal model of HE. Materials and Methods Mice received acetaminophen (APAP,1g/kg, i. p.) and then treated with citicoline (500 mg/kg, i.p) one and two hours after APAP. Animals were monitored for locomotor activity and blood and brain ammonia levels. Moreover, markers of oxidative stress were assessed in the brain tissue. Results The result of the study revealed that plasma and brain ammonia and the liver injury markers increased, and locomotor activity impaired in the APAP-treated animals. Besides, an increase in markers of oxidative stress was evident in the brain of the APAP-treated mice. It was found that citicoline supplementation enhanced the animal’s locomotor activity and improved brain tissue markers of oxidative stress. Conclusion These data propose citicoline as a potential protective agent in HE. The effects of citicoline on oxidative stress markers could play a fundamental role in its neuroprotective properties during HE.
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Affiliation(s)
- Omid Farshad
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Pedram Keshavarz
- Department of Radiology, Tbilisi State Medical University (TSMU), Tbilisi, Georgia
| | - Reza Heidari
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mina Farahmandnejad
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.,Department of Pharmacology and Toxicology, Faculty of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Sara Azhdari
- Department of Anatomy and Embryology, School of Medicine, Bam University of Medical Sciences, Bam, Iran
| | - Akram Jamshidzadeh
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.,Department of Pharmacology and Toxicology, Faculty of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
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7
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Abdoli N, Sadeghian I, Mousavi K, Azarpira N, Ommati MM, Heidari R. Suppression of cirrhosis-related renal injury by N-acetyl cysteine. CURRENT RESEARCH IN PHARMACOLOGY AND DRUG DISCOVERY 2020; 1:30-38. [PMID: 34909640 PMCID: PMC8663932 DOI: 10.1016/j.crphar.2020.100006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 10/02/2020] [Accepted: 10/08/2020] [Indexed: 01/30/2023] Open
Abstract
Cirrhosis-induced renal injury or cholemic nephropathy (CN) is a serious clinical complication with poor prognosis. CN could finally lead to renal failure and the need for organ transplantation. Unfortunately, there is no specific pharmacological intervention against CN to date. On the other hand, various studies mentioned the role of oxidative stress and mitochondrial impairment in the pathogenesis of CN. The current study aimed to evaluate the potential protective effects of NAC as a thiol-reducing agent and antioxidant in CN. Bile duct ligation (BDL) was used as a reliable animal model of cholestasis. BDL animals received NAC (0.25% and 1% w: v) in drinking water for 28 consecutive days. Finally, urine, blood, and kidney samples were collected and analyzed. Significant elevation in serum biomarkers of renal injury, along with urine markers of kidney damage, was evident in the BDL group. Moreover, markers of oxidative stress, including reactive oxygen species (ROS) formation, lipid peroxidation, protein carbonylation, and increased oxidized glutathione (GSSG) were evident detected in the kidney of cholestatic rats. Renal tissue antioxidant capacity and reduced glutathione (GSH) were also significantly depleted in the BDL group. Significant mitochondrial depolarization, depleted ATP content, and mitochondrial permeabilization was also detected in mitochondria isolated from the kidney of cholestatic animals. Renal histopathological alterations consisted of significant tissue fibrosis, interstitial inflammation, and tubular atrophy. It was found that NAC (0.25 and 1% in drinking water for 28 consecutive days) blunted histopathological changes, decreased markers of oxidative stress, and improved mitochondrial indices in the kidney of cirrhotic rats. Moreover, serum and urine biomarkers of renal injury were also mitigated in upon NAC treatment. These data indicate a potential renoprotective role for NAC in cholestasis. The effects of NAC on cellular redox state and mitochondrial function seem to play a fundamental role in its renoprotective effects during CN.
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Affiliation(s)
- Narges Abdoli
- Iran Food and Drug Administration, Ministry of Health, Tehran, Iran
| | - Issa Sadeghian
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Khadijeh Mousavi
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Negar Azarpira
- Transplant Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammad Mehdi Ommati
- College of Life Sciences, Shanxi Agricultural University, Taigu, Shanxi, 030801, China
| | - Reza Heidari
- Iran Food and Drug Administration, Ministry of Health, Tehran, Iran
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8
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Sepehrinezhad A, Zarifkar A, Namvar G, Shahbazi A, Williams R. Astrocyte swelling in hepatic encephalopathy: molecular perspective of cytotoxic edema. Metab Brain Dis 2020; 35:559-578. [PMID: 32146658 DOI: 10.1007/s11011-020-00549-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 02/12/2020] [Indexed: 02/06/2023]
Abstract
Hepatic encephalopathy (HE) may occur in patients with liver failure. The most critical pathophysiologic mechanism of HE is cerebral edema following systemic hyperammonemia. The dysfunctional liver cannot eliminate circulatory ammonia, so its plasma and brain levels rise sharply. Astrocytes, the only cells that are responsible for ammonia detoxification in the brain, are dynamic cells with unique phenotypic properties that enable them to respond to small changes in their environment. Any pathological changes in astrocytes may cause neurological disturbances such as HE. Astrocyte swelling is the leading cause of cerebral edema, which may cause brain herniation and death by increasing intracranial pressure. Various factors may have a role in astrocyte swelling. However, the exact molecular mechanism of astrocyte swelling is not fully understood. This article discusses the possible mechanisms of astrocyte swelling which related to hyperammonia, including the possible roles of molecules like glutamine, lactate, aquaporin-4 water channel, 18 KDa translocator protein, glial fibrillary acidic protein, alanine, glutathione, toll-like receptor 4, epidermal growth factor receptor, glutamate, and manganese, as well as inflammation, oxidative stress, mitochondrial permeability transition, ATP depletion, and astrocyte senescence. All these agents and factors may be targeted in therapeutic approaches to HE.
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Affiliation(s)
- Ali Sepehrinezhad
- Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
| | - Asadollah Zarifkar
- Shiraz Neuroscience Research Center and Department of Physiology, Shiraz University of Medical Sciences (SUMS), Shiraz, Iran
| | - Gholamreza Namvar
- Department of Neuroscience and Cognition, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Ali Shahbazi
- Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran.
- Cellular and Molecular Research Center, Iran University of Medical Sciences (IUMS), Tehran, Iran.
| | - Roger Williams
- The Institute of Hepatology London and Foundation for Liver Research, 111 Coldharbour Lane, London, SE5 9NT, UK.
- Faculty of Life Sciences & Medicine, King's College London, London, UK.
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Jefferson B, Ali M, Grant S, Frampton G, Ploof M, Andry S, DeMorrow S, McMillin M. Thrombospondin-1 Exacerbates Acute Liver Failure and Hepatic Encephalopathy Pathology in Mice by Activating Transforming Growth Factor β1. THE AMERICAN JOURNAL OF PATHOLOGY 2020; 190:347-357. [PMID: 31734229 PMCID: PMC7013272 DOI: 10.1016/j.ajpath.2019.10.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 09/28/2019] [Accepted: 10/21/2019] [Indexed: 12/11/2022]
Abstract
Severe hepatic insults can lead to acute liver failure and hepatic encephalopathy (HE). Transforming growth factor β1 (TGFβ1) has been shown to contribute to HE during acute liver failure; however, TGFβ1 must be activated to bind its receptor and generate downstream effects. One protein that can activate TGFβ1 is thrombospondin-1 (TSP-1). Therefore, the aim of this study was to assess TSP-1 during acute liver failure and HE pathogenesis. C57Bl/6 or TSP-1 knockout (TSP-1-/-) mice were injected with azoxymethane (AOM) to induce acute liver failure and HE. Liver damage, neurologic decline, and molecular analyses of TSP-1 and TGFβ1 signaling were performed. AOM-treated mice had increased TSP-1 and TGFβ1 mRNA and protein expression in the liver. TSP-1-/- mice administered AOM had reduced liver injury as assessed by histology and serum transaminase levels compared with C57Bl/6 AOM-treated mice. TSP-1-/- mice treated with AOM had reduced TGFβ1 signaling that was associated with less hepatic cell death as assessed by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining and cleaved caspase 3 expression. TSP-1-/- AOM-treated mice had a reduced rate of neurologic decline, less cerebral edema, and a decrease in microglia activation in comparison with C57Bl/6 mice treated with AOM. Taken together, TSP-1 is an activator of TGFβ1 signaling during AOM-induced acute liver failure and contributes to both liver pathology and HE progression.
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Affiliation(s)
| | - Malaika Ali
- Central Texas Veterans Health Care System, Austin, Texas
| | - Stephanie Grant
- Department of Medical Physiology, Texas A&M University Health Science Center, Temple, Texas; Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas
| | - Gabriel Frampton
- Department of Medical Physiology, Texas A&M University Health Science Center, Temple, Texas; Department of Internal Medicine, The University of Texas at Austin Dell Medical School, Austin, Texas
| | - Michaela Ploof
- Central Texas Veterans Health Care System, Austin, Texas
| | - Sarah Andry
- Department of Internal Medicine, Baylor Scott & White Health, Temple, Texas
| | - Sharon DeMorrow
- Central Texas Veterans Health Care System, Austin, Texas; Department of Medical Physiology, Texas A&M University Health Science Center, Temple, Texas; Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas; Department of Internal Medicine, The University of Texas at Austin Dell Medical School, Austin, Texas
| | - Matthew McMillin
- Central Texas Veterans Health Care System, Austin, Texas; Department of Internal Medicine, The University of Texas at Austin Dell Medical School, Austin, Texas.
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Grant S, McMillin M, Frampton G, Petrescu AD, Williams E, Jaeger V, Kain J, DeMorrow S. Direct Comparison of the Thioacetamide and Azoxymethane Models of Type A Hepatic Encephalopathy in Mice. Gene Expr 2018; 18:171-185. [PMID: 29895352 PMCID: PMC6190119 DOI: 10.3727/105221618x15287315176503] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Acute liver failure is a devastating consequence of hepatotoxic liver injury that can lead to the development of hepatic encephalopathy. There is no consensus on the best model to represent these syndromes in mice, and therefore the aim of this study was to classify hepatic and neurological consequences of azoxymethane- and thioacetamide-induced liver injury. Azoxymethane-treated mice were euthanized at time points representing absence of minor and significant stages of neurological decline. Thioacetamide-treated mice had tissue collected at up to 3 days following daily injections. Liver histology, serum chemistry, bile acids, and cytokine levels were measured. Reflexes, grip strength measurement, and ataxia were calculated for all groups. Brain ammonia, bile acid levels, cerebral edema, and neuroinflammation were measured. Finally, in vitro and in vivo assessments of blood-brain barrier function were performed. Serum transaminases and liver histology demonstrate that both models generated hepatotoxic liver injury. Serum proinflammatory cytokine levels were significantly elevated in both models. Azoxymethane-treated mice had progressive neurological deficits, while thioacetamide-treated mice had inconsistent neurological deficits. Bile acids and cerebral edema were increased to a higher degree in azoxymethane-treated mice, while cerebral ammonia and neuroinflammation were greater in thioacetamide-treated mice. Blood-brain barrier permeability exists in both models but was likely not due to direct toxicity of azoxymethane or thioacetamide on brain endothelial cells. In conclusion, both models generate acute liver injury and hepatic encephalopathy, but the requirement of a single injection and the more consistent neurological decline make azoxymethane treatment a better model for acute liver failure with hepatic encephalopathy.
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Affiliation(s)
- Stephanie Grant
- *Department of Medical Physiology, Texas A&M Health Science Center College of Medicine, Temple, TX, USA
| | | | - Gabriel Frampton
- *Department of Medical Physiology, Texas A&M Health Science Center College of Medicine, Temple, TX, USA
| | - Anca D. Petrescu
- *Department of Medical Physiology, Texas A&M Health Science Center College of Medicine, Temple, TX, USA
| | - Elaina Williams
- *Department of Medical Physiology, Texas A&M Health Science Center College of Medicine, Temple, TX, USA
| | - Victoria Jaeger
- *Department of Medical Physiology, Texas A&M Health Science Center College of Medicine, Temple, TX, USA
- †Central Texas Veterans Healthcare System, Temple, TX, USA
- ‡Baylor Scott & White Medical Center, Temple, TX, USA
| | - Jessica Kain
- *Department of Medical Physiology, Texas A&M Health Science Center College of Medicine, Temple, TX, USA
| | - Sharon DeMorrow
- *Department of Medical Physiology, Texas A&M Health Science Center College of Medicine, Temple, TX, USA
- †Central Texas Veterans Healthcare System, Temple, TX, USA
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11
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Onk D, Özçelik F, Onk OA, Günay M, Akarsu Ayazoğlu T, Ünver E. Assessment of Renal and Hepatic Tissue-Protective Effects of N-Acetylcysteine via Ammonia Metabolism: A Prospective Randomized Study. Med Sci Monit 2018. [PMID: 29540661 PMCID: PMC5866733 DOI: 10.12659/msm.908172] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Background The present study sought to assess the renal and liver protective effect of N-acetylcysteine through NH3 and urea metabolism in patients with chronic obstructive pulmonary disease who were scheduled for coronary artery bypass grafting surgery. Material/Methods Patients with chronic obstructive pulmonary disease (COPD) who were scheduled for coronary artery bypass grafting were divided into 2 groups so as to receive (Group 1, n=35) or not receive (Group 2, n=35) 900 mg/day of n-acetylcysteine for 7 days before the operation starting from their admission to the service by a pulmonologist with the purpose of treating COPD until the day of surgery. Both groups were subjected to the same anesthesia protocol. Blood samples were taken preoperatively, within the first 15th minute following cessation of the cardiopulmonary bypass, at postoperative 24th hour, and at postoperative 48th hour. Blood tests included ammonia (NH3), lactate, blood urea nitrogen, creatinine, aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), troponin I (Tn I), and creatinine kinase-muscle brain (CKMB). Results There was a significant difference between the groups’ NH3 and lactate levels after cardiopulmonary bypass, postoperative 24th hour, and postoperative 48th hour (respectively, NH3: 39.0±8.8 vs. 55.4±19.6 and 40.1±8.4 vs. 53.2±20.2 mcg/dl, lactate: 1.7±0.9 vs. 2.1±1.2 and 1.2±0.5 vs. 1.8±1.4 mmol/L; p<0.01). Creatinine and BUN levels in Group 2 were found to be significantly higher at the postoperative 48th hour compared to the levels of Group 1 (P<0.05). Conclusions N-acetylcysteine pretreatment appears to improve renal and hepatic functions through regulation of ammonia and nitrogen metabolism and reduction of lactate in patients with chronic obstructive pulmonary disease who undergo coronary artery bypass grafting surgery. We found that N-acetylcysteine improved kidney and/or liver functions.
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Affiliation(s)
- Didem Onk
- Department of Anesthesiology, Faculty of Medicine, Erzincan University, Erzincan, Turkey
| | - Fatih Özçelik
- Department of Medical Biochemistry, Sultan Abdulhamid Han Training Hospital, University of Health Sciences, Istanbul, Turkey
| | - Oruç Alper Onk
- Department of Cardiovascular Surgery, Faculty of Medicine, Erzincan University, Erzincan, Turkey
| | - Murat Günay
- Department of Biochemistry, Faculty of Medicine, Erzincan University, Erzincan, Turkey
| | - Tülin Akarsu Ayazoğlu
- Department of Anesthesiology, Goztepe Training and Research Hospital, Istanbul, Turkey
| | - Ethem Ünver
- Department of Chest Diseases, Faculty of Medicine, Erzincan University, Erzincan, Turkey
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Ommati MM, Jamshidzadeh A, Niknahad H, Mohammadi H, Sabouri S, Heidari R, Abdoli N. N-acetylcysteine treatment blunts liver failure-associated impairment of locomotor activity. PHARMANUTRITION 2017. [DOI: 10.1016/j.phanu.2017.10.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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13
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Nabi T, Nabi S, Rafiq N, Shah A. Role of N-acetylcysteine treatment in non-acetaminophen-induced acute liver failure: A prospective study. Saudi J Gastroenterol 2017; 23:169-175. [PMID: 28611340 PMCID: PMC5470376 DOI: 10.4103/1319-3767.207711] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND/AIMS Acute liver failure (ALF) is a rare but severe medical emergency. To date, there is no established treatment for non-acetaminophen-induced acute liver failure (NAI-ALF) other than liver transplantation, and little is known about the use of N-acetylcysteine (NAC) in NAI-ALF. A randomized case control study was conducted with the aim to determine the effect of NAC on the mortality of NAI-ALF patients, as well as to evaluate the safety and efficacy of NAC use. PATIENTS AND METHODS A total of 80 patients diagnosed with NAI-ALF were included in the study. Forty patients received NAC infusion for 72 h whereas the control group received placebo. The variables evaluated were demographic characteristics, signs and symptoms, biochemical parameters, and clinical course during hospitalization. RESULTS The two groups (NAC and control) were comparable for various baseline characteristics (such as etiology of ALF, INR, alanine aminotransferase, creatinine, albumin, and grade of encephalopathy), except for age. Although majority of patients had undetermined etiology (32.5% in NAC group and 42.5% in control group), the second main cause was acute hepatitis E and drug or toxin-induced ALF. The mortality decreased to 28% with the use of NAC versus 53% in the control group (P = 0.023). The use of NAC was associated with shorter length of hospital stay in survived patients (P = 0.002). Moreover, the survival of patients was improved by NAC (P = 0.025). Also, drug-induced ALF showed improved outcome compared to other etiologies. CONCLUSION The findings of the study recommend the use of NAC along with conventional treatments in patients with NAI-ALF in non-transplant centers while awaiting referrals and conclude the use of NAC as safe.
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Affiliation(s)
- Tauseef Nabi
- Department of Endocrinology, SKIMS, Soura, Srinagar, Jammu and Kashmir, India
| | - Sumaiya Nabi
- Department of Bio-chemistry, University of Kashmir, Srinagar, Jammu and Kashmir, India
| | - Nadeema Rafiq
- Department of Physiology, GMC, Srinagar, Jammu and Kashmir, India
| | - Altaf Shah
- Department of Gastroenterology, SKIMS, Srinagar, Jammu and Kashmir, India
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Esmaeelian B, Benkendorff K, Le Leu RK, Abbott CA. Simultaneous Assessment of the Efficacy and Toxicity of Marine Mollusc-Derived Brominated Indoles in an In Vivo Model for Early Stage Colon Cancer. Integr Cancer Ther 2017; 17:248-262. [PMID: 28381120 PMCID: PMC6041907 DOI: 10.1177/1534735417699880] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The acute apoptotic response to genotoxic carcinogens animal model has been extensively used to assess the ability of drugs and natural products like dietary components to promote apoptosis in the colon and protect against colorectal cancer (CRC). This work aimed to use this model to identify the main chemopreventative agent in extracts from an Australian mollusc Dicathais orbita, while simultaneously providing information on their potential in vivo toxicity. After 2 weeks of daily oral gavage with bioactive extracts and purified brominated indoles, mice were injected with the chemical carcinogen azoxymethane (AOM; 10 mg/kg) and then killed 6 hours later. Efficacy was evaluated using immunohistochemical and hematoxylin staining, and toxicity was assessed via hematology, blood biochemistry, and liver histopathology. Comparison of saline- and AOM-injected controls revealed that potential toxic side effects can be interpreted from blood biochemistry and hematology using this short-term model, although AOM negatively affected the ability to detect histopathological effects in the liver. Purified 6-bromoisatin was identified as the main cancer preventive agent in the Muricidae extract, significantly enhancing apoptosis and reducing cell proliferation in the colonic crypts at 0.05 mg/g. There was no evidence of liver toxicity associated with 6-bromoisatin, whereas 0.1 mg/g of the brominated indole tyrindoleninone led to elevated aspartate aminotransferase levels and a reduction in red blood cells. As tyrindoleninone is converted to 6-bromoisatin by oxidation, this information will assist in the optimization and quality control of a chemopreventative nutraceutical from Muricidae. In conclusion, preliminary data on in vivo safety can be simultaneously collected when testing the efficacy of new natural products, such as 6-bromoisatin from Muricidae molluscs for early stage prevention of colon cancer.
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Affiliation(s)
- Babak Esmaeelian
- School of Biological Sciences, Flinders University, Adelaide, South Australia, Australia
| | - Kirsten Benkendorff
- Marine Ecology Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, New South Wales, Australia
| | - Richard K. Le Leu
- Flinders Centre for Innovation in Cancer, Flinders University, Adelaide, South Australia, Australia
| | - Catherine A. Abbott
- School of Biological Sciences, Flinders University, Adelaide, South Australia, Australia
- Flinders Centre for Innovation in Cancer, Flinders University, Adelaide, South Australia, Australia
- Catherine A. Abbott, School of Biological Sciences, Flinders University, GPO BOX 2100, Adelaide, South Australia 5001, Australia.
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15
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Butterworth RF. The concept of "the inflamed brain" in acute liver failure: mechanisms and new therapeutic opportunities. Metab Brain Dis 2016; 31:1283-1287. [PMID: 26481639 DOI: 10.1007/s11011-015-9747-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 10/05/2015] [Indexed: 12/29/2022]
Abstract
The presence and severity of a systemic inflammatory response is a major predictor of brain edema and encephalopathy in acute liver failure (ALF) and polymorphisms of the gene coding for the proinflammatory cytokine TNF-alpha are known to influence the clinical outcome in ALF. Recent reports provide robust evidence for a role of neuroinflammation(inflammation of the brain per se) in ALF with the cardinal features of neuroinflammation including activation of microglial cells and increased production in situ of pro-inflammatory cytokines such as TNF-alpha and interleukins IL-1beta and IL-6. Multiple liver-brain signalling pathways have been proposed to explain the phenomenon of neuroinflammation in liver failure and these include direct effects of systemically-derived cytokines, recruitment of monocytes relating to microglial activation as well as effects of liver failure-derived toxins and altered permeability of the blood-brain barrier. Synergistic mechanisms involving ammonia and cytokines have been proposed. Currently-available strategies aimed at lowering of blood ammonia such as lactulose, probiotics and rifaximin have the potential to dampen systemic inflammation as does the anti-oxidant N-acetyl cysteine, mild hypothermia and albumin dialysis. Experimental studies demonstrate that deletion of genes coding for TNF-alpha or IL-1 leads to attenuation of the CNS consequences of ALF and administration of the TNF-alpha receptor antagonist etanercept has comparable beneficial effects in experimental ALF. Together, these findings confirm a major role for central neuroinflammatory mechanisms in general and mechanisms involving TNF-alpha in particular in the pathogenesis of the cerebral consequences of ALF and open the door to novel therapeutic interventions in this often fatal disorder.
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16
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Butterworth RF. Pathogenesis of hepatic encephalopathy in cirrhosis: the concept of synergism revisited. Metab Brain Dis 2016; 31:1211-1215. [PMID: 26521983 DOI: 10.1007/s11011-015-9746-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 10/05/2015] [Indexed: 01/31/2023]
Abstract
The concept of synergistic mechanisms as the pathophysiologic basis of hepatic encephalopathy started with the pioneering work of Les Zieve in Minneapolis some 60 years ago where synergistic actions of the liver-derived toxins ammonia, methanethiol, and octanoic acid were described. More recently, synergistic actions of ammonia and manganese, a toxic metal that is normally eliminated via the hepatobiliary route and shown to accumulate in brain in liver failure, on the glutamatergic neurotransmitter system were described. The current upsurge of interest in brain inflammation (neuroinflammation) in relation to the CNS complications of liver failure has added a third dimension to the synergy debate. The combined actions of ammonia, manganese and pro-inflammatory cytokines in brain in liver failure result in oxidative/nitrosative stress resulting from activation of glutamate (NMDA) receptors and consequent nitration of key brain proteins. One such protein, glutamine synthetase, the sole enzyme responsible for brain ammonia removal is nitrated and inactivated in brain in liver failure. Consequently, brain ammonia levels increase disproportionately resulting in alterations of brain excitability, impaired brain energy metabolism, encephalopathy and brain swelling. Experimental therapeutic approaches for which proof-of-principle has been established include the NMDA receptor antagonist memantine, N-acetyl cysteine (recently shown to have antioxidant properties at both hepatic and cerebral levels) and probiotics.
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Affiliation(s)
- Roger F Butterworth
- Department of Medicine, University of Montreal, 45143 Cabot Trail, Englishtown, NS, B0C 1H0, Canada.
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17
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Thomas NO, Shay KP, Kelley AR, Butler JA, Hagen TM. Glutathione maintenance mitigates age-related susceptibility to redox cycling agents. Redox Biol 2016; 10:45-52. [PMID: 27687220 PMCID: PMC5040638 DOI: 10.1016/j.redox.2016.09.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 09/19/2016] [Accepted: 09/20/2016] [Indexed: 12/13/2022] Open
Abstract
Isolated hepatocytes from young (4-6mo) and old (24-26mo) F344 rats were exposed to increasing concentrations of menadione, a vitamin K derivative and redox cycling agent, to determine whether the age-related decline in Nrf2-mediated detoxification defenses resulted in heightened susceptibility to xenobiotic insult. An LC50 for each age group was established, which showed that aging resulted in a nearly 2-fold increase in susceptibility to menadione (LC50 for young: 405μM; LC50 for old: 275μM). Examination of the known Nrf2-regulated pathways associated with menadione detoxification revealed, surprisingly, that NAD(P)H: quinone oxido-reductase 1 (NQO1) protein levels and activity were induced 9-fold and 4-fold with age, respectively (p=0.0019 and p=0.018; N=3), but glutathione peroxidase 4 (GPX4) declined by 70% (p=0.0043; N=3). These results indicate toxicity may stem from vulnerability to lipid peroxidation instead of inadequate reduction of menadione semi-quinone. Lipid peroxidation was 2-fold higher, and GSH declined by a 3-fold greater margin in old versus young rat cells given 300µM menadione (p<0.05 and p≤0.01 respectively; N=3). We therefore provided 400µMN-acetyl-cysteine (NAC) to hepatocytes from old rats before menadione exposure to alleviate limits in cysteine substrate availability for GSH synthesis during challenge. NAC pretreatment resulted in a >2-fold reduction in cell death, suggesting that the age-related increase in menadione susceptibility likely stems from attenuated GSH-dependent defenses. This data identifies cellular targets for intervention in order to limit age-related toxicological insults to menadione and potentially other redox cycling compounds.
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Affiliation(s)
- Nicholas O Thomas
- Linus Pauling Institute, Oregon State University, Corvallis, OR 97331-6512, USA; Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331-7305, USA
| | - Kate P Shay
- Linus Pauling Institute, Oregon State University, Corvallis, OR 97331-6512, USA
| | - Amanda R Kelley
- Linus Pauling Institute, Oregon State University, Corvallis, OR 97331-6512, USA; Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331-7305, USA
| | - Judy A Butler
- Linus Pauling Institute, Oregon State University, Corvallis, OR 97331-6512, USA
| | - Tory M Hagen
- Linus Pauling Institute, Oregon State University, Corvallis, OR 97331-6512, USA; Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331-7305, USA.
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Donnelly MC, Hayes PC, Simpson KJ. Role of inflammation and infection in the pathogenesis of human acute liver failure: Clinical implications for monitoring and therapy. World J Gastroenterol 2016; 22:5958-5970. [PMID: 27468190 PMCID: PMC4948263 DOI: 10.3748/wjg.v22.i26.5958] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2016] [Revised: 05/25/2016] [Accepted: 06/15/2016] [Indexed: 02/06/2023] Open
Abstract
Acute liver failure is a rare and devastating clinical condition. At present, emergency liver transplantation is the only life-saving therapy in advanced cases, yet the feasibility of transplantation is affected by the presence of systemic inflammation, infection and resultant multi-organ failure. The importance of immune dysregulation and acquisition of infection in the pathogenesis of acute liver failure and its associated complications is now recognised. In this review we discuss current thinking regarding the role of infection and inflammation in the pathogenesis of and outcome in human acute liver failure, the implications for the management of such patients and suggest directions for future research.
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Elliott TR, Symes T, Kannourakis G, Angus P. Resolution of norfloxacin-induced acute liver failure after N-acetylcysteine therapy: further support for the use of NAC in drug-induced ALF? BMJ Case Rep 2016; 2016:bcr-2015-213189. [PMID: 26740270 DOI: 10.1136/bcr-2015-213189] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Liver injury due to idiosyncratic drug reactions can be difficult to diagnose and may lead to acute liver failure (ALF), which has a high mortality rate. N-acetylcysteine (NAC) is effective treatment for paracetamol toxicity, but its role in non-paracetamol drug-induced ALF is controversial. We report on the use of a validated bedside tool to establish causality for drug-induced liver injury (DILI) and describe the first case of resolution of norfloxacin-induced ALF after NAC therapy. NAC is easy to administer and generally has a good safety profile. We discuss the evidence to support the use of NAC in ALF secondary to DILI and possibilities for further clinical research in this field.
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Affiliation(s)
| | - Tiffany Symes
- Pathology Department, St John of God Hospital, Ballarat, Victoria, Australia
| | | | - Peter Angus
- Victorian Liver Transplant Unit and Department of Gastroenterology, Austin Hospital, Melbourne, Australia
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20
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Oxidative Stress and Inflammation in Hepatic Diseases: Therapeutic Possibilities of N-Acetylcysteine. Int J Mol Sci 2015; 16:30269-308. [PMID: 26694382 PMCID: PMC4691167 DOI: 10.3390/ijms161226225] [Citation(s) in RCA: 143] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Revised: 12/02/2015] [Accepted: 12/04/2015] [Indexed: 12/12/2022] Open
Abstract
Liver disease is highly prevalent in the world. Oxidative stress (OS) and inflammation are the most important pathogenetic events in liver diseases, regardless the different etiology and natural course. N-acetyl-l-cysteine (the active form) (NAC) is being studied in diseases characterized by increased OS or decreased glutathione (GSH) level. NAC acts mainly on the supply of cysteine for GSH synthesis. The objective of this review is to examine experimental and clinical studies that evaluate the antioxidant and anti-inflammatory roles of NAC in attenuating markers of inflammation and OS in hepatic damage. The results related to the supplementation of NAC in any form of administration and type of study are satisfactory in 85.5% (n = 59) of the cases evaluated (n = 69, 100%). Within this percentage, the dosage of NAC utilized in studies in vivo varied from 0.204 up to 2 g/kg/day. A standard experimental design of protection and treatment as well as the choice of the route of administration, with a broader evaluation of OS and inflammation markers in the serum or other biological matrixes, in animal models, are necessary. Clinical studies are urgently required, to have a clear view, so that, the professionals can be sure about the effectiveness and safety of NAC prescription.
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Bile Acid Signaling Is Involved in the Neurological Decline in a Murine Model of Acute Liver Failure. THE AMERICAN JOURNAL OF PATHOLOGY 2015; 186:312-23. [PMID: 26683664 DOI: 10.1016/j.ajpath.2015.10.005] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 10/06/2015] [Accepted: 10/09/2015] [Indexed: 12/13/2022]
Abstract
Hepatic encephalopathy is a serious neurological complication of liver failure. Serum bile acids are elevated after liver damage and may disrupt the blood-brain barrier and enter the brain. Our aim was to assess the role of serum bile acids in the neurological complications after acute liver failure. C57Bl/6 or cytochrome p450 7A1 knockout (Cyp7A1(-/-)) mice were fed a control, cholestyramine-containing, or bile acid-containing diet before azoxymethane (AOM)-induced acute liver failure. In parallel, mice were given an intracerebroventricular infusion of farnesoid X receptor (FXR) Vivo-morpholino before AOM injection. Liver damage, neurological decline, and molecular analyses of bile acid signaling were performed. Total bile acid levels were increased in the cortex of AOM-treated mice. Reducing serum bile acids via cholestyramine feeding or using Cyp7A1(-/-) mice reduced bile acid levels and delayed AOM-induced neurological decline, whereas cholic acid or deoxycholic acid feeding worsened AOM-induced neurological decline. The expression of bile acid signaling machinery apical sodium-dependent bile acid transporter, FXR, and small heterodimer partner increased in the frontal cortex, and blocking FXR signaling delayed AOM-induced neurological decline. In conclusion, circulating bile acids may play a pathological role during hepatic encephalopathy, although precisely how they dysregulate normal brain function is unknown. Strategies to minimize serum bile acid concentrations may reduce the severity of neurological complications associated with liver failure.
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Abstract
Hepatic encephalopathy (HE) is a severe neuropsychiatric complication of acute and chronic liver dysfunction, and is characterized by a spectrum that ranges from mild neuropsychological disturbances to coma. Although ammonia plays a critical role in the pathogenesis of HE, the plasma concentrations of ammonia and manifest symptoms of HE are not always consistent in patients with HE. Recently, a substantial body of evidence has indicated that inflammation acts in concert with ammonia in the pathogenesis of HE. Meanwhile, emerging novel and potential therapeutic strategies, including N-acetylcysteine, hypothermia, minocycline, non-steroidal anti-inflammatory drugs, tumour necrosis factor-alpha antagonists and p38 inhibitors, have been reported to ameliorate systemic inflammation and neuroinflammation, improve or reverse neuropsychiatric manifestations, and prevent the onset and progression of HE in patients and/or animal models of acute or chronic liver failure. These results point to the possible therapeutic utility of decreasing inflammation in the treatment of HE, and translation of these experimental results to the clinic may provide novel and promising therapeutic approaches for patients with HE secondary to acute or chronic liver failure. This review will provide an overview of these potential targeted therapies in the prophylaxis and treatment of HE.
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Hu J, Zhang Q, Ren X, Sun Z, Quan Q. Efficacy and safety of acetylcysteine in "non-acetaminophen" acute liver failure: A meta-analysis of prospective clinical trials. Clin Res Hepatol Gastroenterol 2015; 39:594-9. [PMID: 25732608 DOI: 10.1016/j.clinre.2015.01.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 12/01/2014] [Accepted: 01/05/2015] [Indexed: 02/04/2023]
Abstract
BACKGROUND Acute liver failure (ALF) is a rare but highly mortal condition without liver transplantation (LT). N-acetylcysteine (NAC), a glutathione precursor that detoxifies the reactive metabolite of acetaminophen and replenishes hepatic glutathione stores, is a highly effective drug for the prevention of ALF caused by acetaminophen. However, therapeutic use of NAC in non-acetaminophen-induced ALF (NAI-ALF) including alcohol intoxication, hepatitis virus infection, or drug and toxin-related hepatotoxicity is still inconclusive. The aim of this article is using meta-analysis method to analyze recent prospective clinical trials for the safety and efficacy of NAC in patients with ALF not caused by acetaminophen poisoning. METHODS Prospective clinical trials comparing efficacy and safety between NAC and control in the treatment of NAI-ALF were identified by searching Pubmed (2000-2014) and EMBASE (2000-2014) using the search terms acetylcysteine or NAC and NAI-ALF. The primary outcome was overall survival. Secondary outcomes included liver transplantation-free survival, post transplantation survival, length of ICU and hospital stays, and the relationship with coma grade. The safety profiles were also analyzed. RESULTS Four clinical trials were selected for meta-analysis. A total of 331 patients receiving treatment with NAC (oral or intravenously) and 285 patients in control group were included for meta-analysis. No statistical difference was identified between NAC group and control group for overall survival [236/331 (71%) vs 191/285 (67%); 95% CI 1.16 (0.81-1.67); P=0.42]. However, there were significant differences between NAC group and control group regarding the survival with native liver [112/273 (41%) vs 68/226 (30%); 95% CI 1.61 (1.11-2.34); P=0.01] and post-transplantation survival [78/91 (85.7%) vs 50/70 (71.4%); 95% CI 2.44 (1.11-5.37); P=0.03]. The identified side effects of NAC included nausea, vomiting, and diarrhea or constipation. Rarely, it could cause rashes, fever, headache, drowsiness, low blood pressure, and elevated serum transaminase levels in a patient with cystic fibrosis. At the dose used for acetaminophen toxicity, acetylcysteine does not have hepatotoxic effects. CONCLUSION NAC is safe for NAI-ALF. It can prolong patients' survival with native liver without transplantation and survival after transplantation, but it cannot improve the overall survival.
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Affiliation(s)
- Jinhua Hu
- Department of Gastroenterology, Jinan Military General Hospital, 25, Shifan Road, Jinan, Shandong, 250031, China
| | - Qizhi Zhang
- The fifth People's Hospital of Jinan, Jinan, Shandong, 250031, China
| | - Xingye Ren
- The fifth People's Hospital of Jinan, Jinan, Shandong, 250031, China
| | - Ziqin Sun
- Department of Gastroenterology, Jinan Military General Hospital, 25, Shifan Road, Jinan, Shandong, 250031, China
| | - Qizhen Quan
- Department of Gastroenterology, Jinan Military General Hospital, 25, Shifan Road, Jinan, Shandong, 250031, China.
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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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Butterworth RF. Pathogenesis of hepatic encephalopathy and brain edema in acute liver failure. J Clin Exp Hepatol 2015; 5:S96-S103. [PMID: 26041966 PMCID: PMC4442857 DOI: 10.1016/j.jceh.2014.02.004] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Accepted: 02/07/2014] [Indexed: 12/12/2022] Open
Abstract
Neuropathologic investigations in acute liver failure (ALF) reveal significant alterations to neuroglia consisting of swelling of astrocytes leading to cytotoxic brain edema and intracranial hypertension as well as activation of microglia indicative of a central neuroinflammatory response. Increased arterial ammonia concentrations in patients with ALF are predictors of patients at risk for the development of brain herniation. Molecular and spectroscopic techniques in ALF reveal alterations in expression of an array of genes coding for neuroglial proteins involved in cell volume regulation and mitochondrial function as well as in the transport of neurotransmitter amino acids and in the synthesis of pro-inflammatory cytokines. Liver-brain pro-inflammatory signaling mechanisms involving transduction of systemically-derived cytokines, ammonia neurotoxicity and exposure to increased brain lactate have been proposed. Mild hypothermia and N-Acetyl cysteine have both hepato-protective and neuro-protective properties in ALF. Potentially effective anti-inflammatory agents aimed at control of encephalopathy and brain edema in ALF include etanercept and the antibiotic minocycline, a potent inhibitor of microglial activation. Translation of these potentially-interesting findings to the clinic is anxiously awaited.
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Key Words
- ALF, acute liver failure
- ATP, adenosine triphosphate
- BBB, blood-brain barrier
- CCL2, chemokine ligand-2
- CMRO2, cerebral metabolic rate for oxygen
- CNS, central nervous system
- EEG, electroencephalography
- GABA, gamma-aminobutyric acid
- GFAP, glial fibrillary acidic protein
- IgG, immunoglobulin
- MRS, magnetic resonance spectroscopy
- NAC, N-Acetyl cysteine
- NMDA, N-methyl-d-aspartate
- SIRS, systemic inflammatory response syndrome
- SNATs, several neutral amino acid transport systems
- TLP, translocator protein
- TNFα, tumor necrosis factor alpha
- acute liver failure
- hepatic encephalopathy
- intracranial hypertension
- microglial activation
- neuroinflammation
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Affiliation(s)
- Roger F. Butterworth
- Neuroscience Research Unit, Hopital St-Luc (CHUM) and Department of Medicine, University of Montreal, Montreal, QC H2W 3J4, Canada,Address for correspondence: Roger F. Butterworth, Neuroscience Research Unit, Hospital St-Luc (CHUM) and Department of Medicine, University of Montreal, 1058 St Denis, Montreal, QC H2W 3J4, Canada. Tel.: +1 902 929 2470.
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Zhang CL, Duan ZJ, Tian G, Tian Y, He GH, Bian TF, Jin X, Sun XY, Liu Z, Chang QY. pH-sensitive microemulsion-based gels for removal of colonic ammonia: a novel preventative oral preparation for hepatic encephalopathy in rats. Mol Med Rep 2015; 11:3925-33. [PMID: 25591795 DOI: 10.3892/mmr.2015.3201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 09/19/2014] [Indexed: 11/06/2022] Open
Abstract
Microemulsions with limited stability in mimetic gastrointestinal environments have previously demonstrated potential for the effective removal of ammonia from artificial colonic fluid. Specialized pH‑sensitive microemulsion‑based gels for the removal of colonic ammonia (MBG‑RCA), however, possess relative stability in the gastrointestinal (GI) tract of normal rats, indicating potential use in in vivo applications. An investigation of the effects of oral MBG‑RCA was conducted in order to evaluate the reduction of intestinal ammonia and the prevention of hepatic encephalopathy (HE) in rat models. Eighty rats were allocated into eight 4‑day treatment groups: The HE model (intraperitoneal injection of thioacetamide) group; the high‑, medium‑ and low‑dose MBG‑RCA therapeutic groups (15, 10 and 5 ml/kg MBG‑RCA, respectively); and the normal, blank, lactulose and acetic acid control groups, each of which received daily treatment administration. Oral MBG‑RCA effects were identified using behavioral monitoring observed by an infrared night vision supervisory control system, electroencephalograms, blood ammonia levels, intestinal ammonia levels, liver functionality and pathological observation. High‑ and medium‑dose oral administrations of MBG‑RCA significantly decreased the blood and intestinal ammonia levels (P<0.05), improved liver functionality and reduced the clinical manifestations of HE in rats. MBG‑RCA demonstrated high clearance of rat colonic ammonia while maintaining sufficient stability in the GI tract, indicating the potential for the development of new clinically relevant oral preparations for the prevention of HE. Additionally, such preparations are advantageous in that ammonia is eliminated without the production of potentially harmful metabolic byproducts.
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Affiliation(s)
- Chun-Le Zhang
- Department of Gastroenterology, First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116011, P.R. China
| | - Zhi-Jun Duan
- Department of Gastroenterology, First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116011, P.R. China
| | - Ge Tian
- Pharmaceutical College, Dalian Medical University, Dalian, Liaoning 116044, P.R. China
| | - Yan Tian
- Pharmaceutical College, Dalian Medical University, Dalian, Liaoning 116044, P.R. China
| | - Gao-Hong He
- Membrane Science and Technology Center, Dalian University of Technology, Dalian, Liaoning 116012, P.R. China
| | - Teng-Fei Bian
- Membrane Science and Technology Center, Dalian University of Technology, Dalian, Liaoning 116012, P.R. China
| | - Xue Jin
- Department of Gastroenterology, First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116011, P.R. China
| | - Xiao-Yu Sun
- Department of Gastroenterology, First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116011, P.R. China
| | - Zhen Liu
- Department of Gastroenterology, First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116011, P.R. China
| | - Qing-Yong Chang
- Department of Neurosurgery, Zhongshan Affiliated Hospital of Dalian University, Dalian, Liaoning 116001, P.R. China
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Wright GAK, Sharifi Y, Newman TA, Davies N, Vairappan B, Perry HV, Jalan R. Characterisation of temporal microglia and astrocyte immune responses in bile duct-ligated rat models of cirrhosis. Liver Int 2014; 34:1184-91. [PMID: 24528887 DOI: 10.1111/liv.12481] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 01/31/2014] [Indexed: 12/24/2022]
Abstract
BACKGROUND & AIMS Microglia and astrocyte related pro-inflammatory responses are thought to underpin cerebral sequelae of acute liver failure. Conversely, despite background pro-inflammatory responses in cirrhosis, overt brain swelling and coma associated with acute-on-chronic liver failure, is infrequent unless precipitated (e.g. sepsis). Moreover in other chronic neurodegenerative disorders and sepsis, the brain is protected from recurrent microbial insults by compensatory microglial-associated immune responses. To characterise longitudinal cerebral immune responses in a bile duct-ligated (BDL) rat model of cirrhosis. METHOD Rats underwent BDL or sham operation before sacrifice at either 1-day, 1, 2 and 4 weeks post-surgery. We analysed consciousness, brain water, biochemistry and immunohistochemistry to assess activation of microglia (ED-1, OX6 and Iba-1), astrocytes (Glial fibrillary acidic protein - GFAP), cellular stress (Heat shock protein - Hsp 25) and pro-inflammatory mediator expression (inducible nitric oxide synthase (iNOS), interleukin-1beta (IL-1β) and tumour growth factor-beta (TGF-β)). RESULTS BDL significantly increased ammonia and bilirubin (P < 0.01 respectively). The classical microglial markers OX6, ED1 and Iba-1 and pro-inflammatory IL-1β and iNOS were not significantly increased. However, the alternative microglial marker and regulatory cytokine TGF-β was elevated from day 1 to 4 weeks post-BDL. GFAP expression was significantly increased in corpus callosum in all groups. In BDL rats, Hsp 25 was also increased in the corpus callosum, peaking at 2 weeks. CONCLUSION BDL triggers early alternative, but not classical, microglial activation. There was a correlation between astrocyte activation and cellular stress. These findings indicate early cerebral immune responses, which may be associated with immune tolerance to further challenge.
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Affiliation(s)
- Gavin A K Wright
- Institute of Hepatology, University College London, Royal Free Hospital London, London, UK
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Faleiros BE, Miranda AS, Campos AC, Gomides LF, Kangussu LM, Guatimosim C, Camargos ERS, Menezes GB, Rachid MA, Teixeira AL. Up-regulation of brain cytokines and chemokines mediates neurotoxicity in early acute liver failure by a mechanism independent of microglial activation. Brain Res 2014; 1578:49-59. [PMID: 25017944 DOI: 10.1016/j.brainres.2014.07.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 06/07/2014] [Accepted: 07/01/2014] [Indexed: 12/12/2022]
Abstract
The neurological involvement in acute liver failure (ALF) is characterized by arousal impairment with progression to coma. There is a growing body of evidence that neuroinflammatory mechanisms play a role in this process, including production of inflammatory cytokines and microglial activation. However, it is still uncertain whether brain-derived cytokines and glial cells are crucial to the pathophysiology of ALF at the early stage, before coma development. Here, we investigated the influence of cytokines and microglia in ALF-induced encephalopathy in mice as soon as neurological symptoms were identifiable. Behavior was assessed at 12, 24, 36 and 48 h post-injection of thioacetamide, a hepatotoxic drug, through locomotor activity by an open field test. Brain concentration of cytokines (TNF-α and IL-1β) and chemokines (CXCL1, CCL2, CCL3 and CCL5) were assessed by ELISA. Microglial activation in brain sections was investigated through immunohistochemistry, and cellular ultrastructural changes were observed by transmission electron microscopy. We found that ALF-induced animals presented a significant decrease in locomotor activity at 24 h, which was accompanied by an increase in IL-1β, CXCL1, CCL2, CCL3 and CCL5 in the brain. TNF-α level was significantly increased only at 36 h. Despite marked morphological changes in astrocytes and brain endothelial cells, no microglial activation was observed. These findings suggest an involvement of brain-derived chemokines and IL-1β in early pathophysiology of ALF by a mechanism independent of microglial activation.
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Affiliation(s)
- Bruno E Faleiros
- Interdisciplinary Laboratory of Medical Investigation, School of Medicine, Universidade Federal de Minas Gerais, Avenida Alfredo Balena 190, Santa Efigênia, Belo Horizonte, MG 30130-100, Brazil.
| | - Aline S Miranda
- Interdisciplinary Laboratory of Medical Investigation, School of Medicine, Universidade Federal de Minas Gerais, Avenida Alfredo Balena 190, Santa Efigênia, Belo Horizonte, MG 30130-100, Brazil
| | - Alline C Campos
- Interdisciplinary Laboratory of Medical Investigation, School of Medicine, Universidade Federal de Minas Gerais, Avenida Alfredo Balena 190, Santa Efigênia, Belo Horizonte, MG 30130-100, Brazil
| | - Lindisley F Gomides
- Department of Morphology, Institute of Biological Sciences, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Avenida Antônio Carlos 6627, Pampulha, Belo Horizonte, MG 31270-901, Brazil
| | - Lucas M Kangussu
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Avenida Antônio Carlos 6627, Pampulha, Belo Horizonte, MG 31270-901, Brazil
| | - Cristina Guatimosim
- Department of Morphology, Institute of Biological Sciences, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Avenida Antônio Carlos 6627, Pampulha, Belo Horizonte, MG 31270-901, Brazil
| | - Elizabeth R S Camargos
- Department of Morphology, Institute of Biological Sciences, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Avenida Antônio Carlos 6627, Pampulha, Belo Horizonte, MG 31270-901, Brazil
| | - Gustavo B Menezes
- Department of Morphology, Institute of Biological Sciences, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Avenida Antônio Carlos 6627, Pampulha, Belo Horizonte, MG 31270-901, Brazil
| | - Milene A Rachid
- Department of Pathology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Avenida Antônio Carlos 6627, Pampulha, Belo Horizonte, MG 31270-901, Brazil
| | - Antônio L Teixeira
- Interdisciplinary Laboratory of Medical Investigation, School of Medicine, Universidade Federal de Minas Gerais, Avenida Alfredo Balena 190, Santa Efigênia, Belo Horizonte, MG 30130-100, Brazil.
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30
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Czaja AJ. Hepatic inflammation and progressive liver fibrosis in chronic liver disease. World J Gastroenterol 2014; 20:2515-32. [PMID: 24627588 PMCID: PMC3949261 DOI: 10.3748/wjg.v20.i10.2515] [Citation(s) in RCA: 242] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 10/24/2013] [Accepted: 11/12/2013] [Indexed: 02/06/2023] Open
Abstract
Chronic liver inflammation drives hepatic fibrosis, and current immunosuppressive, anti-inflammatory, and anti-viral therapies can weaken this driver. Hepatic fibrosis is reversed, stabilized, or prevented in 57%-79% of patients by conventional treatment regimens, mainly by their anti-inflammatory actions. Responses, however, are commonly incomplete and inconsistently achieved. The fibrotic mechanisms associated with liver inflammation have been clarified, and anti-fibrotic agents promise to improve outcomes as adjunctive therapies. Hepatitis C virus and immune-mediated responses can activate hepatic stellate cells by increasing oxidative stress within hepatocytes. Angiotensin can be synthesized by activated hepatic stellate cells and promote the production of reactive oxygen species. Anti-oxidants (N-acetylcysteine, S-adenosyl-L-methionine, and vitamin E) and angiotensin inhibitors (losartin) have had anti-fibrotic actions in preliminary human studies, and they may emerge as supplemental therapies. Anti-fibrotic agents presage a new era of supplemental treatment for chronic liver disease.
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Chastre A, Bélanger M, Nguyen BN, Butterworth RF. Lipopolysaccharide precipitates hepatic encephalopathy and increases blood-brain barrier permeability in mice with acute liver failure. Liver Int 2014; 34:353-61. [PMID: 23910048 DOI: 10.1111/liv.12252] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 05/16/2013] [Accepted: 05/31/2013] [Indexed: 12/25/2022]
Abstract
BACKGROUND & AIMS Acute liver failure (ALF) is frequently complicated by infection leading to precipitation of central nervous system complications such as hepatic encephalopathy (HE) and increased mortality. There is evidence to suggest that when infection occurs in ALF patients, the resulting pro-inflammatory mechanisms may be amplified that could, in turn, have a major impact on blood-brain barrier (BBB) function. The aim of this study was to investigate the role of endotoxemia on the progression of encephalopathy in relation to BBB permeability during ALF. METHODS Adult male C57-BL6 mice with ALF resulting from azoxymethane-induced toxic liver injury were administered trace amounts of the endotoxin component lipopolysaccharide (LPS). Effects on the magnitude of the systemic inflammatory response, liver pathology and BBB integrity were measured as a function of progression of HE, defined as time to loss of corneal reflex (coma). RESULTS Lipopolysaccharide caused additional two- to seven-fold (P < 0.001) increases in circulating pro-inflammatory cytokines (TNF-α, IL-1β, IL-6), worsening liver pathology and associated increases of circulating transaminases as well as increased hyperammonaemia consistent with a further loss of viable hepatocytes. LPS treatment of ALF mice led to a rapid precipitation of hepatic coma and the BBB became permeable to the 25-kDa protein immunoglobulin G (IgG). This extravasation of IgG was accompanied by ignificant up-regulation of matrix metalloproteinase-9 (MMP-9), an endopeptidase known to modulate opening of the BBB in a wide range of neurological disorders. CONCLUSIONS These findings represent the first direct evidence of inflammation-related BBB permeability changes in ALF.
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Affiliation(s)
- Anne Chastre
- Neuroscience Research Unit, Saint-Luc Hospital, CRCHUM, Montreal, QC, Canada
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Aritomi K, Ishitsuka Y, Tomishima Y, Shimizu D, Abe N, Shuto T, Irikura M, Kai H, Irie T. Evaluation of Three-Dimensional Cultured HepG2 Cells in a Nano Culture Plate System: an In Vitro Human Model of Acetaminophen Hepatotoxicity. J Pharmacol Sci 2014; 124:218-29. [DOI: 10.1254/jphs.13135fp] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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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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Du X, Ewert DL, Cheng W, West MB, Lu J, Li W, Floyd RA, Kopke RD. Effects of antioxidant treatment on blast-induced brain injury. PLoS One 2013; 8:e80138. [PMID: 24224042 PMCID: PMC3818243 DOI: 10.1371/journal.pone.0080138] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 09/30/2013] [Indexed: 11/19/2022] Open
Abstract
Blast-induced traumatic brain injury has dramatically increased in combat troops in today’s military operations. We previously reported that antioxidant treatment can provide protection to the peripheral auditory end organ, the cochlea. In the present study, we examined biomarker expression in the brains of rats at different time points (3 hours to 21 days) after three successive 14 psi blast overpressure exposures to evaluate antioxidant treatment effects on blast-induced brain injury. Rats in the treatment groups received a combination of antioxidants (2,4-disulfonyl α-phenyl tertiary butyl nitrone and N-acetylcysteine) one hour after blast exposure and then twice a day for the following two days. The biomarkers examined included an oxidative stress marker (4-hydroxy-2-nonenal, 4-HNE), an immediate early gene (c-fos), a neural injury marker (glial fibrillary acidic protein, GFAP) and two axonal injury markers [amyloid beta (A4) precursor protein, APP, and 68 kDa neurofilament, NF-68]. The results demonstrate that blast exposure induced or up-regulated the following: 4-HNE production in the dorsal hippocampus commissure and the forceps major corpus callosum near the lateral ventricle; c-fos and GFAP expression in most regions of the brain, including the retrosplenial cortex, the hippocampus, the cochlear nucleus, and the inferior colliculus; and NF-68 and APP expression in the hippocampus, the auditory cortex, and the medial geniculate nucleus (MGN). Antioxidant treatment reduced the following: 4-HNE in the hippocampus and the forceps major corpus callosum, c-fos expression in the retrosplenial cortex, GFAP expression in the dorsal cochlear nucleus (DCN), and APP and NF-68 expression in the hippocampus, auditory cortex, and MGN. This preliminary study indicates that antioxidant treatment may provide therapeutic protection to the central auditory pathway (the DCN and MGN) and the non-auditory central nervous system (hippocampus and retrosplenial cortex), suggesting that these compounds have the potential to simultaneously treat blast-induced injuries in the brain and auditory system.
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Affiliation(s)
- Xiaoping Du
- Hough Ear Institute, Oklahoma City, Oklahoma, United States of America
| | - Donald L. Ewert
- Hough Ear Institute, Oklahoma City, Oklahoma, United States of America
| | - Weihua Cheng
- Hough Ear Institute, Oklahoma City, Oklahoma, United States of America
| | - Matthew B. West
- Hough Ear Institute, Oklahoma City, Oklahoma, United States of America
| | - Jianzhong Lu
- Hough Ear Institute, Oklahoma City, Oklahoma, United States of America
| | - Wei Li
- Hough Ear Institute, Oklahoma City, Oklahoma, United States of America
| | - Robert A. Floyd
- Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Richard D. Kopke
- Hough Ear Institute, Oklahoma City, Oklahoma, United States of America
- Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
- Departments of Physiology and Otolaryngology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- * E-mail:
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Stravitz RT, Sanyal AJ, Reisch J, Bajaj JS, Mirshahi F, Cheng J, Lee WM. Effects of N-acetylcysteine on cytokines in non-acetaminophen acute liver failure: potential mechanism of improvement in transplant-free survival. Liver Int 2013; 33:1324-31. [PMID: 23782487 PMCID: PMC4994536 DOI: 10.1111/liv.12214] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2013] [Accepted: 05/05/2013] [Indexed: 12/12/2022]
Abstract
BACKGROUND N-Acetylcysteine (NAC) improves transplant-free survival in patients with non-acetaminophen acute liver failure (ALF) when administered in early stages of hepatic encephalopathy. The mechanisms of this benefit are unknown. AIM To determine whether NAC improves transplant-free survival in ALF by ameliorating the surge of pro-inflammatory cytokines. METHODS Serum samples were obtained from 78 participants of the randomized, ALF Study Group NAC Trial with grade 1 or 2 hepatic encephalopathy on randomization. Concentrations of ten cytokines, chosen to represent a wide array of inflammatory responses, were determined by multiplex enzyme-linked immunosorbent assay ELISA. RESULTS In univariate analysis, predictors of transplant-free survival included NAC administration (P = 0.012), admission bilirubin (P = 0.003), international normalized ratio INR (P = 0.0002), grade 1 vs. grade 2 encephalopathy (P = 0.006) and lower admission interleukin (IL)-17 concentrations (P = 0.011). IL-17 levels were higher in patients with grade 2 vs. grade 1 encephalopathy on randomization (P = 0.007) and in those who progressed to grade 3 or grade 4 encephalopathy over the following 7 days (P ≤ 0.01). Stepwise multivariate logistic regression analysis identified only NAC administration and lower IL-17 concentrations as independent predictors of transplant-free survival. In patients with detectable IL-17 concentrations on admission, 78% of those who received NAC vs. 44% of those who received placebo had undetectable levels by day 3-5 (P = 0.042), and the mean decrease in IL-17 concentrations between admission and late samples was significantly greater in patients who received NAC vs. placebo (P = 0.045). CONCLUSIONS N-acetylcysteine (NAC) may improve transplant-free survival in patients with non-acetaminophen ALF by ameliorating the production of IL-17, which is associated with progression of hepatic encephalopathy and poor outcome.
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Affiliation(s)
- R Todd Stravitz
- Section of Hepatology, Division of Gastroenterology, Hepatology and Nutrition and the Hume-Lee Transplant Center, Virginia Commonwealth University, Richmond, VA, USA
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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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Sahin S, Alatas O. The protective effects of n-acetylcysteine against acute hepatotoxicity. Indian J Gastroenterol 2013; 32:311-5. [PMID: 23475548 DOI: 10.1007/s12664-013-0316-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 02/04/2013] [Indexed: 02/04/2023]
Abstract
OBJECTIVES N-acetylcysteine (NAC) increases tissue levels of glutathione and has been widely investigated as a protective and antioxidative agent. This study evaluated the protective effect of NAC on under carbon tetrachloride (CCl4)-induced acute liver injury in the rat. METHODS Three-month-old Sprague-Dawley rats were intraperitoneally administered 4 mL/kg CCl4 (1:1 dissolved in olive oil, group 1) or 4 mL/kg CCl4 + NAC 150 mg/kg, 3 and 6 h after CCL4 (group 2) or 4 mL/kg olive oil (group 3, control). Twenty-four hours after administering CCl4, all of the rats were sacrificed. Biochemical assessment of serum transaminases and malonaldehyde (MDA) and tissue MDA, myeloperoxidase (MPO), and nitric oxide was done. Histopathological assessments were performed. RESULTS Serum transaminases and tissue and serum MDA and tissue MPO were all increased in group 1 compared to control and were significantly decreased in the group treated with NAC. Histopathological comparison of the groups showed a decrease in congestion, polymorphonuclear leukocytes, mononuclear leukocytes, vacuolar degeneration of hepatocyte, and hepatocellular necrosis in the group treated with NAC. CONCLUSION Our results suggest that NAC prevents experimental acute hepatic failure by preventing oxidative stress.
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Affiliation(s)
- Sabiha Sahin
- Department Pediatrics, ESOGUMF, Eskisehir, Turkey.
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Bémeur C, Butterworth RF. Liver-brain proinflammatory signalling in acute liver failure: role in the pathogenesis of hepatic encephalopathy and brain edema. Metab Brain Dis 2013; 28:145-50. [PMID: 23212479 DOI: 10.1007/s11011-012-9361-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 11/05/2012] [Indexed: 12/12/2022]
Abstract
A robust neuroinflammatory response characterized by microglial activation and increased brain production of pro-inflammatory cytokines is common in acute liver failure (ALF). Mechanisms proposed to explain the neuroinflammatory response in ALF include direct effects of systemically-derived proinflammatory cytokines and the effects of brain lactate accumulation on pro-inflammatory cytokine release from activated microglia. Cell culture studies reveal a positive synergistic effect of ammonia and pro-inflammatory cytokines on the expression of proteins involved in glutamate homeostasis and in oxidative/nitrosative stress. Proinflammatory cytokines have the capacity to alter blood-brain barrier (BBB) integrity and preliminary studies suggest that the presence of infection in ALF results in rupture of the BBB and vasogenic brain edema. Treatments currently under investigation that are effective in prevention of encephalopathy and brain edema in ALF which are aimed at reduction of neuroinflammation in ALF include mild hypothermia, albumin dialysis systems, N-acetyl cysteine and the antibiotic minocycline with potent anti-inflammatory actions that are distinct from its anti-microbial properties.
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Affiliation(s)
- Chantal Bémeur
- Département de nutrition, Faculté de médecine, Université de Montréal, Montréal, QC, Canada
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Mettananda S, Fernando AD, Ginige N. Posterior reversible encephalopathy syndrome in a survivor of valproate-induced acute liver failure: a case report. J Med Case Rep 2013; 7:144. [PMID: 23724918 PMCID: PMC3680161 DOI: 10.1186/1752-1947-7-144] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 04/29/2013] [Indexed: 12/27/2022] Open
Abstract
Introduction Posterior reversible encephalopathy syndrome is an extremely rare radiological diagnosis that has not been reported previously in association with acute liver failure. Case presentation A 6-year-old Sri Lankan girl developed acute liver failure with severe hepatic encephalopathy due to sodium valproate. She was successfully treated medically with N-acetylcysteine and L-carnitine. During recovery she again developed features of encephalopathy and had repeated convulsions associated with moderate hypertension. The diagnosis of posterior reversible encephalopathy syndrome was made on clinical and radiological grounds and she showed a gradual improvement with control of blood pressure. Conclusions This report adds to the evidence behind treatment of valproate-induced acute liver failure with N-acetylcysteine and L-carnitine and illustrates a rare but interesting association between acute liver failure and posterior reversible encephalopathy syndrome.
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Affiliation(s)
- Sachith Mettananda
- Department of Paediatrics, Faculty of Medicine, University of Kelaniya, P,O, Box 6, Ragama, Sri Lanka.
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40
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Chastre A, Bélanger M, Beauchesne E, Nguyen BN, Desjardins P, Butterworth RF. Inflammatory cascades driven by tumor necrosis factor-alpha play a major role in the progression of acute liver failure and its neurological complications. PLoS One 2012; 7:e49670. [PMID: 23166746 PMCID: PMC3499491 DOI: 10.1371/journal.pone.0049670] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 10/12/2012] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND/AIMS Acute liver failure (ALF) due to ischemic or toxic liver injury is a clinical condition that results from massive loss of hepatocytes and may lead to hepatic encephalopathy (HE), a serious neuropsychiatric complication. Although increased expression of tumor necrosis factor-alpha (TNF-α) in liver, plasma and brain has been observed, conflicting results exist concerning its roles in drug-induced liver injury and on the progression of HE. The present study aimed to investigate the therapeutic value of etanercept, a TNF-α neutralizing molecule, on the progression of liver injury and HE in mice with ALF resulting from azoxymethane (AOM) hepatotoxicity. METHODS/PRINCIPAL FINDINGS Mice were administered saline or etanercept (10 mg/kg; i.p.) 30 minutes prior to, or up to 6 h after AOM. Etanercept-treated ALF mice were sacrificed in parallel with vehicle-treated comatose ALF mice and controls. AOM induced severe hepatic necrosis, leading to HE, and etanercept administered prior or up to 3 h after AOM significantly delayed the onset of coma stages of HE. Etanercept pretreatment attenuated AOM-induced liver injury, as assessed by histological examination, plasma ammonia and transaminase levels, and by hepatic glutathione content. Peripheral inflammation was significantly reduced by etanercept as shown by decreased plasma IL-6 (4.1-fold; p<0.001) and CD40L levels (3.7-fold; p<0.001) compared to saline-treated ALF mice. Etanercept also decreased IL-6 levels in brain (1.2-fold; p<0.05), attenuated microglial activation (assessed by OX-42 immunoreactivity), and increased brain glutathione concentrations. CONCLUSIONS These results indicate that systemic sequestration of TNF-α attenuates both peripheral and cerebral inflammation leading to delayed progression of liver disease and HE in mice with ALF due to toxic liver injury. These results suggest that etanercept may provide a novel therapeutic approach for the management of ALF patients awaiting liver transplantation.
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Affiliation(s)
- Anne Chastre
- Neuroscience Research Unit, Hôpital Saint-Luc, CRCHUM, Montreal, Canada
| | - Mireille Bélanger
- Neuroscience Research Unit, Hôpital Saint-Luc, CRCHUM, Montreal, Canada
| | | | - Bich N. Nguyen
- Département de pathologie, Hôpital Saint-Luc, CHUM, Montreal, Canada
| | - Paul Desjardins
- Neuroscience Research Unit, Hôpital Saint-Luc, CRCHUM, Montreal, Canada
| | - Roger F. Butterworth
- Neuroscience Research Unit, Hôpital Saint-Luc, CRCHUM, Montreal, Canada
- * E-mail:
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Moling O, Tappeiner L, Piccin A, Pagani E, Rossi P, Rimenti G, Vedovelli C, Mian P. Treatment of DIHS/DRESS syndrome with combined N-acetylcysteine, prednisone and valganciclovir--a hypothesis. Med Sci Monit 2012; 18:CS57-62. [PMID: 22739739 PMCID: PMC3560780 DOI: 10.12659/msm.883198] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Background Drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms (DIHS/DRESS) is a rare and severe adverse drug reaction with an associated mortality of 10–20%. Clinical worsening despite discontinuation of the culprit drug is considered a characteristic feature of DIHS/DRESS. Besides the early recognition of the syndrome and discontinuation of its causative drug, the mainstay of treatment is systemic corticosteroids. Nevertheless, treatment of severe DIHS/DRESS is not well defined, as corticosteroids may sometimes not be effective, and decreasing the dose may be associated with flaring of the disease. Case Report A 38-year-old woman with high fever, malaise, abdominal pain, rash, and elevated liver enzymes received immediate high-dose N-acetylcysteine, because acetaminophen hepatotoxicity was suspected. N-acetylcysteine administration was associated with a significant clinical improvement. However, within the next week DIHS/DRESS syndrome was diagnosed, which explained all the symptoms, and which was subsequently treated with prednisone and valganciclovir. Conclusions New options necessary to improve treatment of severe DIHD/DRESS have to consider its sequential pathogenetic mechanisms. N-acetylcysteine might neutralize the drug-derived reactive metabolites, which are responsible for protein adduct formation and specific T cell stimulation, and replete the glutathione stores that counterbalance oxidative stress. Prednisone might inhibit lymphoproliferation and valganciclovir might prevent complications related to HHV-6 reactivation. We therefore propose the unprecedented combination of N-acetylcysteine, prednisone and valganciclovir as a treatment option for DIHS/DRESS.
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Affiliation(s)
- Oswald Moling
- Division of Infectious Diseases, Ospedale Generale, Bolzano, Italy.
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Advances in the current treatment of autoimmune hepatitis. Dig Dis Sci 2012; 57:1996-2010. [PMID: 22476586 DOI: 10.1007/s10620-012-2151-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Accepted: 03/16/2012] [Indexed: 12/17/2022]
Abstract
Current treatment strategies for autoimmune hepatitis are complicated by frequent relapse after drug withdrawal, medication intolerance, and refractory disease. The objective of this review is to describe advances that have improved treatment outcomes by defining the optimum objectives of initial therapy, managing relapse more effectively, identifying problematic patients early, and incorporating the new pharmacological interventions that have emerged as frontline and salvage therapies. Initial corticosteroid treatment should be continued until serum aminotransferase, γ-globulin, and immunoglobulin G levels are normal, and maintenance of this improvement for 3-8 months before liver tissue assessment. Improvement to normal liver tissue is the ideal histological result that justifies drug withdrawal, but it is achievable in only 22 % of patients. Minimum portal hepatitis, inactive cirrhosis, or minimally active cirrhosis is the most common treatment end point. Relapse after drug withdrawal warrants institution of a long-term maintenance regimen, preferably with azathioprine. Mathematical models can identify problematic adult patients early, as also can clinical phenotype (age ≤ 30 years and HLA DRB1 03), rapidity of treatment response (≤ 24 months), presence of antibodies to soluble liver antigen, and non-white ethnicity. The calcineurin inhibitors (cyclosporine and tacrolimus) can be effective in steroid-refractory disease; mycophenolate mofetil can be corticosteroid-sparing and effective for azathioprine intolerance; budesonide combined with azathioprine can be effective for treatment-naïve, non-cirrhotic patients. Standard treatment regimens for autoimmune hepatitis can be upgraded without adjustments that require major new expertise.
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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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Butterworth RF. Reprint of: Neuroinflammation in acute liver failure: mechanisms and novel therapeutic targets. Neurochem Int 2012; 60:715-22. [PMID: 22504574 DOI: 10.1016/j.neuint.2012.03.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Revised: 07/20/2011] [Accepted: 07/28/2011] [Indexed: 01/31/2023]
Abstract
It is increasingly evident that neuroinflammatory mechanisms are implicated in the pathogenesis of the central nervous system (CNS) complications (intracranial hypertension, brain herniation) of acute liver failure (ALF). Neuroinflammation in ALF is characterized by microglial activation and arterio-venous difference studies as well as studies of gene expression confirm local brain production and release of proinflammatory cytokines including TNF-α and the interleukins IL-1β and IL-6. Although the precise nature of the glial cell responsible for brain cytokine synthesis is not yet established, evidence to date supports a role for both astrocytes and microglia. The neuroinflammatory response in ALF progresses in parallel with the progression of hepatic encephalopathy (HE) and with the severity of brain edema (astrocyte swelling). Mechanisms responsible for the relaying of signals from the failing liver to the brain include transduction of systemic proinflammatory signals as well as the effects of increased brain lactate leading to increased release of cytokines from both astrocytes and microglia. There is evidence in support of a synergistic effect of proinflammatory cytokines and ammonia in the pathogenesis of HE and brain edema in ALF. Therapeutic implications of the findings of a neuroinflammatory response in ALF are multiple. Removal of both ammonia and proinflammatory cytokines is possible using antibiotics or albumen dialysis. Mild hypothermia reduces brain ammonia transfer, brain lactate production, microglial activation and proinflammatory cytokine production resulting in reduced brain edema and intracranial pressure in ALF. N-Acetylcysteine acts as both an antioxidant and anti-inflammatory agent at both peripheral and central sites of action independently resulting in slowing of HE progression and prevention of brain edema. Novel treatments that directly target the neuroinflammatory response in ALF include the use of etanercept, a TNF-α neutralizing molecule and minocycline, an agent with potent inhibitory actions on microglial activation that are independent of its antimicrobial properties; both agents have been shown to be effective in reducing neuroinflammation and in preventing the CNS complications of ALF. Translation of these findings to the clinic has the potential to provide rational targeted approaches to the prevention and treatment of these complications in the near future.
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Affiliation(s)
- Roger F Butterworth
- Neuroscience Research Unit, Saint-Luc Hospital, CHUM, University of Montreal, Montreal, Quebec, Canada.
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Abstract
BACKGROUND A reliable model of fulminant liver failure (FLF) is urgently required in this research field. This study aimed to develop a murine FLF model. METHODS We used three groups of male C57BL/6 mice: control, with azoxymethane treatment (AOM group), and with galactosamine and tumor necrosis factor-alpha treatment (Gal+TNF-alpha group). The effects of body temperature (BT) control on survival in all three groups were investigated. Using BT control, we compared the survival, histopathological findings and biochemical/coagulation profiles between the two experimental groups. The effects of hydration on international normalized ratios of prothrombin time (PT-INRs) were also checked. Dose-dependent survival curves were constructed for both experimental groups. Neurological behavior was assessed using a coma scale. RESULTS No unexpected BT effects were seen in the control group. The AOM group, but not the Gal+TNF-alpha group, showed a significant difference in survival curves between those with and without BT care. Histopathological assessment showed consistent FLF findings in both experimental groups with BT care. There were significant differences between the experimental groups in aspartate aminotransferase levels and PT-INRs, and significant differences in PT-INRs between the sufficiently and insufficiently hydrated groups. There were significant differences between FLF models in the duration of each coma stage, with significant differences in stages 1 and 3 as percentages of the disease state (stages 1-4). The two FLF models with BT care showed different survival curves in the dose-dependent survival study. CONCLUSIONS AOM provides a good FLF model, but requires a specialized environment and careful BT control. Other FLF models may also be useful, depending on the research purpose. Thoughtful attention to caregiving and close observation are indispensable for successful FLF models.
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46
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Nguyen JH. Blood-brain barrier in acute liver failure. Neurochem Int 2011; 60:676-83. [PMID: 22100566 DOI: 10.1016/j.neuint.2011.10.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Revised: 10/20/2011] [Accepted: 10/26/2011] [Indexed: 12/16/2022]
Abstract
Brain edema remains a challenging obstacle in the management of acute liver failure (ALF). Cytotoxic mechanisms associated with brain edema have been well recognized, but evidence for vasogenic mechanisms in the pathogenesis of brain edema in ALF has been lacking. Recent reports have not only shown a role of matrix metalloproteinase-9 in the pathogenesis of brain edema in experimental ALF but have also found significant alterations in the tight junction elements including occludin and claudin-5, suggesting a vasogenic injury in the blood-brain barrier (BBB) integrity. This article reviews and explores the role of the paracellular tight junction proteins in the increased selective BBB permeability that leads to brain edema in ALF.
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Affiliation(s)
- Justin H Nguyen
- Division of Transplant Surgery, Department of Transplantation, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224, United States.
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47
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Butterworth RF. Neuroinflammation in acute liver failure: mechanisms and novel therapeutic targets. Neurochem Int 2011; 59:830-6. [PMID: 21864609 DOI: 10.1016/j.neuint.2011.07.014] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Revised: 07/20/2011] [Accepted: 07/28/2011] [Indexed: 12/21/2022]
Abstract
It is increasingly evident that neuroinflammatory mechanisms are implicated in the pathogenesis of the central nervous system (CNS) complications (intracranial hypertension, brain herniation) of acute liver failure (ALF). Neuroinflammation in ALF is characterized by microglial activation and arterio-venous difference studies as well as studies of gene expression confirm local brain production and release of proinflammatory cytokines including TNF-α and the interleukins IL-1β and IL-6. Although the precise nature of the glial cell responsible for brain cytokine synthesis is not yet established, evidence to date supports a role for both astrocytes and microglia. The neuroinflammatory response in ALF progresses in parallel with the progression of hepatic encephalopathy (HE) and with the severity of brain edema (astrocyte swelling). Mechanisms responsible for the relaying of signals from the failing liver to the brain include transduction of systemic proinflammatory signals as well as the effects of increased brain lactate leading to increased release of cytokines from both astrocytes and microglia. There is evidence in support of a synergistic effect of proinflammatory cytokines and ammonia in the pathogenesis of HE and brain edema in ALF. Therapeutic implications of the findings of a neuroinflammatory response in ALF are multiple. Removal of both ammonia and proinflammatory cytokines is possible using antibiotics or albumen dialysis. Mild hypothermia reduces brain ammonia transfer, brain lactate production, microglial activation and proinflammatory cytokine production resulting in reduced brain edema and intracranial pressure in ALF. N-Acetylcysteine acts as both an antioxidant and anti-inflammatory agent at both peripheral and central sites of action independently resulting in slowing of HE progression and prevention of brain edema. Novel treatments that directly target the neuroinflammatory response in ALF include the use of etanercept, a TNF-α neutralizing molecule and minocycline, an agent with potent inhibitory actions on microglial activation that are independent of its antimicrobial properties; both agents have been shown to be effective in reducing neuroinflammation and in preventing the CNS complications of ALF. Translation of these findings to the clinic has the potential to provide rational targeted approaches to the prevention and treatment of these complications in the near future.
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Affiliation(s)
- Roger F Butterworth
- Neuroscience Research Unit, Saint-Luc Hospital (CHUM), University of Montreal, Montreal, Quebec, Canada.
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48
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Bandi S, Joseph B, Berishvili E, Singhania R, Wu YM, Cheng K, Gupta S. Perturbations in ataxia telangiectasia mutant signaling pathways after drug-induced acute liver failure and their reversal during rescue of animals by cell therapy. THE AMERICAN JOURNAL OF PATHOLOGY 2010; 178:161-74. [PMID: 21224054 DOI: 10.1016/j.ajpath.2010.11.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2009] [Revised: 08/31/2010] [Accepted: 09/14/2010] [Indexed: 11/26/2022]
Abstract
Superior insights into molecular mechanisms of liver failure, which are not fully understood, will help strategies for inducing liver regeneration. We examined hepatotoxic mechanisms in mice homozygous for the severe combined immune deficiency mutation in the protein kinase, DNA-activated, catalytic polypeptide. Mice were treated with rifampicin, phenytoin, and monocrotaline. The ensuing acute liver failure was characterized by serological, histological, and mRNA studies. Subsequently, we studied whether transplantation of hepatocytes could rescue animals with liver failure. We found extensive liver damage in these animals, with mortality over several days. The expression of multiple hepatic genes was rapidly altered, including those representing pathways in oxidative/metabolic stress, inflammation, DNA damage-repair, and ataxia telangiectasia mutant (Atm) signaling pathways. This led to liver cell growth arrest involving cyclin-dependent kinase inhibitor 1A. Transplantation of hepatocytes with microcarriers in the peritoneal cavity efficiently rescued animals with liver failure. Molecular abnormalities rapidly reversed, including in hepatic Atm and downstream signaling pathways; and residual hepatocytes overcame cyclin-dependent kinase inhibitor 1A-induced cell growth arrest. Reseeding of the liver with transplanted hepatocytes was not required for rescue because native hepatocytes overcame cell growth-arrest to regenerate the liver. This likely resulted from paracrine signaling from hepatocytes in the peritoneal cavity. We concluded that Atm signaling played critical roles in the pathological features of liver failure. These studies should help redirect examination of pathophysiologic and therapeutic mechanisms in liver failure.
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Affiliation(s)
- Sriram Bandi
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
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Role of nutrition in the management of hepatic encephalopathy in end-stage liver failure. J Nutr Metab 2010; 2010:489823. [PMID: 21234351 PMCID: PMC3017957 DOI: 10.1155/2010/489823] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Accepted: 11/11/2010] [Indexed: 02/07/2023] Open
Abstract
Malnutrition is common in patients with end-stage liver failure and hepatic encephalopathy, and is considered a significant prognostic factor affecting quality of life, outcome, and survival. The liver plays a crucial role in the regulation of nutrition by trafficking the metabolism of nutrients, their distribution and appropriate use by the body. Nutritional consequences with the potential to cause nervous system dysfunction occur in liver failure, and many factors contribute to malnutrition in hepatic failure. Among them are inadequate dietary intake, malabsorption, increased protein losses, hypermetabolism, insulin resistance, gastrointestinal bleeding, ascites, inflammation/infection, and hyponatremia. Patients at risk of malnutrition are relatively difficult to identify since liver disease may interfere with biomarkers of malnutrition. The supplementation of the diet with amino acids, antioxidants, vitamins as well as probiotics in addition to meeting energy and protein requirements may improve nutritional status, liver function, and hepatic encephalopathy in patients with end-stage liver failure.
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50
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Reactive astrocytes give neurons less support: implications for Alzheimer's disease. Neurobiol Aging 2010; 33:423.e1-13. [PMID: 21051108 DOI: 10.1016/j.neurobiolaging.2010.09.018] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Revised: 09/20/2010] [Accepted: 09/20/2010] [Indexed: 11/20/2022]
Abstract
Astrocytes become activated in Alzheimer's disease (AD), contributing to and reinforcing an inflammatory cascade. It is proposed that by transforming from a basal to a reactive state, astrocytes neglect their neurosupportive functions, thus rendering neurons vulnerable to excitotoxicity and oxidative stress. This review considers 3 important astrocytic functions, that when disrupted, can affect neuronal metabolism. These are the uptake of glucose and release of lactate; the uptake of glutamate and release of glutamine; and the uptake of glutathione precursors and release of glutathione. Conditions under which these functions can be manipulated in vitro, as well as examples of possible loss of astrocytic function in AD, are discussed. It is proposed that the targeting of astrocytes with pharmacological agents that are specifically designed to return astrocytes to a quiescent phenotype could represent a fruitful new angle for the therapeutic treatment of AD and other neurodegenerative disorders.
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