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Carretero VJ, Ramos E, Segura-Chama P, Hernández A, Baraibar AM, Álvarez-Merz I, Muñoz FL, Egea J, Solís JM, Romero A, Hernández-Guijo JM. Non-Excitatory Amino Acids, Melatonin, and Free Radicals: Examining the Role in Stroke and Aging. Antioxidants (Basel) 2023; 12:1844. [PMID: 37891922 PMCID: PMC10603966 DOI: 10.3390/antiox12101844] [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: 09/05/2023] [Revised: 09/23/2023] [Accepted: 09/26/2023] [Indexed: 10/29/2023] Open
Abstract
The aim of this review is to explore the relationship between melatonin, free radicals, and non-excitatory amino acids, and their role in stroke and aging. Melatonin has garnered significant attention in recent years due to its diverse physiological functions and potential therapeutic benefits by reducing oxidative stress, inflammation, and apoptosis. Melatonin has been found to mitigate ischemic brain damage caused by stroke. By scavenging free radicals and reducing oxidative damage, melatonin may help slow down the aging process and protect against age-related cognitive decline. Additionally, non-excitatory amino acids have been shown to possess neuroprotective properties, including antioxidant and anti-inflammatory in stroke and aging-related conditions. They can attenuate oxidative stress, modulate calcium homeostasis, and inhibit apoptosis, thereby safeguarding neurons against damage induced by stroke and aging processes. The intracellular accumulation of certain non-excitatory amino acids could promote harmful effects during hypoxia-ischemia episodes and thus, the blockade of the amino acid transporters involved in the process could be an alternative therapeutic strategy to reduce ischemic damage. On the other hand, the accumulation of free radicals, specifically mitochondrial reactive oxygen and nitrogen species, accelerates cellular senescence and contributes to age-related decline. Recent research suggests a complex interplay between melatonin, free radicals, and non-excitatory amino acids in stroke and aging. The neuroprotective actions of melatonin and non-excitatory amino acids converge on multiple pathways, including the regulation of calcium homeostasis, modulation of apoptosis, and reduction of inflammation. These mechanisms collectively contribute to the preservation of neuronal integrity and functions, making them promising targets for therapeutic interventions in stroke and age-related disorders.
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Affiliation(s)
- Victoria Jiménez Carretero
- Department of Pharmacology and Therapeutic, Teófilo Hernando Institute, Faculty of Medicine, Universidad Autónoma de Madrid, Av. Arzobispo Morcillo 4, 28029 Madrid, Spain
| | - Eva Ramos
- Department of Pharmacology and Toxicology, Faculty of Veterinary Medicine, Complutense University of Madrid, 28040 Madrid, Spain
| | - Pedro Segura-Chama
- Investigador por México-CONAHCYT, Instituto Nacional de Psiquiatría "Ramón de la Fuente Muñiz", Calzada México-Xochimilco 101, Huipulco, Tlalpan, Mexico City 14370, Mexico
| | - Adan Hernández
- Institute of Neurobiology, Universidad Nacional Autónoma of México, Juriquilla, Santiago de Querétaro 76230, Querétaro, Mexico
| | - Andrés M Baraibar
- Department of Neurosciences, Universidad del País Vasco UPV/EHU, Achucarro Basque Center for Neuroscience, Barrio Sarriena, s/n, 48940 Leioa, Spain
| | - Iris Álvarez-Merz
- Department of Pharmacology and Therapeutic, Teófilo Hernando Institute, Faculty of Medicine, Universidad Autónoma de Madrid, Av. Arzobispo Morcillo 4, 28029 Madrid, Spain
| | - Francisco López Muñoz
- Faculty of Health Sciences, University Camilo José Cela, C/Castillo de Alarcón 49, Villanueva de la Cañada, 28692 Madrid, Spain
- Neuropsychopharmacology Unit, Hospital 12 de Octubre Research Institute (i + 12), Avda. Córdoba, s/n, 28041 Madrid, Spain
| | - Javier Egea
- Molecular Neuroinflammation and Neuronal Plasticity Research Laboratory, Hospital Universitario Santa Cristina, Health Research Institute, Hospital Universitario de la Princesa, 28006 Madrid, Spain
| | - José M Solís
- Neurobiology-Research Service, Hospital Ramón y Cajal, Carretera de Colmenar Viejo, Km. 9, 28029 Madrid, Spain
| | - Alejandro Romero
- Department of Pharmacology and Toxicology, Faculty of Veterinary Medicine, Complutense University of Madrid, 28040 Madrid, Spain
| | - Jesús M Hernández-Guijo
- Department of Pharmacology and Therapeutic, Teófilo Hernando Institute, Faculty of Medicine, Universidad Autónoma de Madrid, Av. Arzobispo Morcillo 4, 28029 Madrid, Spain
- Ramón y Cajal Institute for Health Research (IRYCIS), Hospital Ramón y Cajal, Carretera de Colmenar Viejo, Km. 9, 28029 Madrid, Spain
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2
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Álvarez-Merz I, Muñoz MD, Hernández-Guijo JM, Solís JM. Identification of Non-excitatory Amino Acids and Transporters Mediating the Irreversible Synaptic Silencing After Hypoxia. Transl Stroke Res 2023:10.1007/s12975-023-01192-y. [PMID: 37755645 DOI: 10.1007/s12975-023-01192-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 08/03/2023] [Accepted: 09/01/2023] [Indexed: 09/28/2023]
Abstract
The contribution of excitatory amino acids (AA) to ischemic brain injury has been widely described. In addition, we reported that a mixture of non-excitatory AA at plasmatic concentrations turns irreversible the depression of synaptic transmission caused by hypoxia. Here, we describe that the presence of seven non-excitatory AA (L-alanine, L-glutamine, glycine, L-histidine, L-serine, taurine, and L-threonine) during hypoxia provokes an irreversible neuronal membrane depolarization, after an initial phase of hyperpolarization. The collapse of the membrane potential correlates with a great increase in fiber volley amplitude. Nevertheless, we show that the presence of all seven AA is not necessary to cause the irreversible loss of fEPSP after hypoxia and that the minimal combination of AA able to provoke a solid, replicable effect is the mixture of L-alanine, glycine, L-glutamine, and L-serine. Additionally, L-glutamine seems necessary but insufficient to induce these harmful effects. We also prove that the deleterious effects of the AA mixtures on field potentials during hypoxia depend on both the identity and concentration of the individual AA in the mixture. Furthermore, we find that the accumulation of AA in the whole slice does not determine the outcome caused by the AA mixtures on the synaptic transmission during hypoxia. Finally, results obtained using pharmacological inhibitors and specific substrates of AA transporters suggest that system N and the alanine-serine-cysteine transporter 2 (ASCT2) participate in the non-excitatory AA-mediated deleterious effects during hypoxia. Thus, these AA transporters might represent therapeutical targets for the treatment of brain ischemia.
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Affiliation(s)
- Iris Álvarez-Merz
- Departamento de Farmacología y Terapéutica, Facultad de Medicina, Instituto Teófilo Hernando, Universidad Autónoma de Madrid, Madrid, Spain
- Servicio de Neurobiología-Investigación, Hospital Ramón y Cajal, IRYCIS, Madrid, Spain
| | - María-Dolores Muñoz
- Servicio de Neurobiología-Investigación, Hospital Ramón y Cajal, IRYCIS, Madrid, Spain
| | - Jesús M Hernández-Guijo
- Departamento de Farmacología y Terapéutica, Facultad de Medicina, Instituto Teófilo Hernando, Universidad Autónoma de Madrid, Madrid, Spain.
- Servicio de Neurobiología-Investigación, Hospital Ramón y Cajal, IRYCIS, Madrid, Spain.
| | - José M Solís
- Servicio de Neurobiología-Investigación, Hospital Ramón y Cajal, IRYCIS, Madrid, Spain
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3
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Di Vincenzo F, Nicoletti A, Negri M, Vitale F, Zileri Dal Verme L, Gasbarrini A, Ponziani FR, Cerrito L. Gut Microbiota and Antibiotic Treatments for the Main Non-Oncologic Hepato-Biliary-Pancreatic Disorders. Antibiotics (Basel) 2023; 12:1068. [PMID: 37370387 DOI: 10.3390/antibiotics12061068] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 06/10/2023] [Accepted: 06/15/2023] [Indexed: 06/29/2023] Open
Abstract
The gut microbiota is a pivotal actor in the maintenance of the balance in the complex interconnections of hepato-biliary-pancreatic system. It has both metabolic and immunologic functions, with an influence on the homeostasis of the whole organism and on the pathogenesis of a wide range of diseases, from non-neoplastic ones to tumorigenesis. The continuous bidirectional metabolic communication between gut and hepato-pancreatic district, through bile ducts and portal vein, leads to a continuous interaction with translocated bacteria and their products. Chronic liver disease and pancreatic disorders can lead to reduced intestinal motility, decreased bile acid synthesis and intestinal immune dysfunction, determining a compositional and functional imbalance in gut microbiota (dysbiosis), with potentially harmful consequences on the host's health. The modulation of the gut microbiota by antibiotics represents a pioneering challenge with striking future therapeutic opportunities, even in non-infectious diseases. In this setting, antibiotics are aimed at harmonizing gut microbial function and, sometimes, composition. A more targeted and specific approach should be the goal to pursue in the future, tailoring the treatment according to the type of microbiota modulation to be achieved and using combined strategies.
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Affiliation(s)
- Federica Di Vincenzo
- Internal Medicine and Gastroenterology, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, 00168 Rome, Italy
| | - Alberto Nicoletti
- Internal Medicine and Gastroenterology, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, 00168 Rome, Italy
| | - Marcantonio Negri
- Internal Medicine and Gastroenterology, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, 00168 Rome, Italy
| | - Federica Vitale
- Internal Medicine and Gastroenterology, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, 00168 Rome, Italy
| | - Lorenzo Zileri Dal Verme
- Internal Medicine and Gastroenterology, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, 00168 Rome, Italy
| | - Antonio Gasbarrini
- Internal Medicine and Gastroenterology, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, 00168 Rome, Italy
- Dipartimento Universitario di Medicina e Chirurgia Traslazionale, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
| | - Francesca Romana Ponziani
- Internal Medicine and Gastroenterology, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, 00168 Rome, Italy
- Dipartimento Universitario di Medicina e Chirurgia Traslazionale, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
| | - Lucia Cerrito
- Internal Medicine and Gastroenterology, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, 00168 Rome, Italy
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4
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Jo D, Lim YH, Jung YS, Kim YK, Song J. Circular RNA Tmcc1 improves astrocytic glutamate metabolism and spatial memory via NF-κB and CREB signaling in a bile duct ligation mouse model: transcriptional and cellular analyses. J Neuroinflammation 2023; 20:121. [PMID: 37217942 DOI: 10.1186/s12974-023-02806-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 05/16/2023] [Indexed: 05/24/2023] Open
Abstract
BACKGROUND Hepatic encephalopathy-induced hyperammonemia alters astrocytic glutamate metabolism in the brain, which is involved in cognitive decline. To identify specific therapeutic strategies for the treatment of hepatic encephalopathy, various molecular signaling studies, such as non-coding RNA functional study, have been conducted. However, despite several reports of circular RNAs (circRNAs) in the brain, few studies of circRNAs in hepatic encephalopathy-induced neuropathophysiological diseases have been conducted. METHODS In this study, we performed RNA sequencing to identify whether the candidate circRNA cirTmcc1 is specifically expressed in the brain cortex in a bile duct ligation (BDL) mouse model of hepatic encephalopathy. RESULTS Based on transcriptional and cellular analysis, we investigated the circTmcc1-dysregulation-induced changes in the expression of several genes that are associated with intracellular metabolism and astrocyte function. We found that the circTmcc1 binds with the NF-κB p65-CREB transcriptional complex and regulates the expression of the astrocyte transporter EAAT2. Furthermore, circTmcc1 contributed to the secretion of proinflammatory mediators and glutamate metabolism in astrocytes and subsequently modulated an improvement in spatial memory by mediating neuronal synaptic plasticity. CONCLUSIONS Thus, circTmcc1 may be a promising circRNA candidate for targeted interventions to prevent and treat the neuropathophysiological complications that occur due to hepatic encephalopathy.
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Affiliation(s)
- Danbi Jo
- Department of Anatomy, Chonnam National University Medical School, Seoyangro 264, Jeollanam-Do, Hwasun, 58128, Republic of Korea
- Chonnam National University, Seoyangro 264, Hwasun, 58128, Republic of Korea
| | - Yeong-Hwan Lim
- Department of Biochemistry, Chonnam National University Medical School, Seoyangro 264, Hwasun, 58128, Republic of Korea
| | - Yoon Seok Jung
- Department of Anatomy, Chonnam National University Medical School, Seoyangro 264, Jeollanam-Do, Hwasun, 58128, Republic of Korea
| | - Young-Kook Kim
- Department of Biochemistry, Chonnam National University Medical School, Seoyangro 264, Hwasun, 58128, Republic of Korea
| | - Juhyun Song
- Department of Anatomy, Chonnam National University Medical School, Seoyangro 264, Jeollanam-Do, Hwasun, 58128, Republic of Korea.
- Chonnam National University, Seoyangro 264, Hwasun, 58128, Republic of Korea.
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5
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Jia P, Wang J, Ren X, He J, Wang S, Xing Y, Chen D, Zhang X, Zhou S, Liu X, Yu S, Li Z, Jiang C, Zang W, Chen X, Wang J. An enriched environment improves long-term functional outcomes in mice after intracerebral hemorrhage by mechanisms that involve the Nrf2/BDNF/glutaminase pathway. J Cereb Blood Flow Metab 2023; 43:694-711. [PMID: 36635875 PMCID: PMC10108193 DOI: 10.1177/0271678x221135419] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 09/22/2022] [Accepted: 09/23/2022] [Indexed: 01/14/2023]
Abstract
Post-stroke depression exacerbates neurologic deficits and quality of life. Depression after ischemic stroke is known to some extent. However, depression after intracerebral hemorrhage (ICH) is relatively unknown. Increasing evidence shows that exposure to an enriched environment (EE) after cerebral ischemia/reperfusion injury has neuroprotective effects in animal models, but its impact after ICH is unknown. In this study, we investigated the effect of EE on long-term functional outcomes in mice subjected to collagenase-induced striatal ICH. Mice were subjected to ICH with the standard environment (SE) or ICH with EE for 6 h/day (8:00 am-2:00 pm). Depressive, anxiety-like behaviors and cognitive tests were evaluated on day 28 with the sucrose preference test, tail suspension test, forced swim test, light-dark transition experiment, morris water maze, and novel object recognition test. Exposure to EE improved neurologic function, attenuated depressive and anxiety-like behaviors, and promoted spatial learning and memory. These changes were associated with increased expression of transcription factor Nrf2 and brain-derived neurotrophic factor (BDNF) and inhibited glutaminase activity in the perihematomal tissue. However, EE did not change the above behavioral outcomes in Nrf2-/- mice on day 28. Furthermore, exposure to EE did not increase BDNF expression compared to exposure to SE in Nrf2-/- mice on day 28 after ICH. These findings indicate that EE improves long-term outcomes in sensorimotor, emotional, and cognitive behavior after ICH and that the underlying mechanism involves the Nrf2/BDNF/glutaminase pathway.
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Affiliation(s)
- Peijun Jia
- Department of Anatomy,
School of Basic Medical Sciences, , Zhengzhou
University, Zhengzhou, China
- School of Life Sciences,
Zhengzhou University, Zhengzhou, China
| | - Junmin Wang
- Department of Anatomy,
School of Basic Medical Sciences, , Zhengzhou
University, Zhengzhou, China
| | - Xiuhua Ren
- Department of Anatomy,
School of Basic Medical Sciences, , Zhengzhou
University, Zhengzhou, China
| | - Jinxin He
- Department of Anatomy,
School of Basic Medical Sciences, , Zhengzhou
University, Zhengzhou, China
| | - Shaoshuai Wang
- Department of Anatomy,
School of Basic Medical Sciences, , Zhengzhou
University, Zhengzhou, China
| | - Yinpei Xing
- Department of Anatomy,
School of Basic Medical Sciences, , Zhengzhou
University, Zhengzhou, China
| | - Danyang Chen
- Department of Anatomy,
School of Basic Medical Sciences, , Zhengzhou
University, Zhengzhou, China
| | - Xinling Zhang
- Department of Anatomy,
School of Basic Medical Sciences, , Zhengzhou
University, Zhengzhou, China
| | - Siqi Zhou
- Department of Anatomy,
School of Basic Medical Sciences, , Zhengzhou
University, Zhengzhou, China
| | - Xi Liu
- Department of Neurology,
The First Affiliated Hospital of Zhengzhou University, Zhengzhou,
China
| | - Shangchen Yu
- Department of Anatomy,
School of Basic Medical Sciences, , Zhengzhou
University, Zhengzhou, China
| | - Zefu Li
- Department of Anatomy,
School of Basic Medical Sciences, , Zhengzhou
University, Zhengzhou, China
| | - Chao Jiang
- Department of Neurology,
The Fifth Affiliated Hospital of Zhengzhou University, Zhengzhou,
China
| | - Weidong Zang
- Department of Anatomy,
School of Basic Medical Sciences, , Zhengzhou
University, Zhengzhou, China
| | - Xuemei Chen
- Department of Anatomy,
School of Basic Medical Sciences, , Zhengzhou
University, Zhengzhou, China
| | - Jian Wang
- Department of Anatomy,
School of Basic Medical Sciences, , Zhengzhou
University, Zhengzhou, China
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6
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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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7
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Sepehrinezhad A, Stolze Larsen F, Ashayeri Ahmadabad R, Shahbazi A, Sahab Negah S. The Glymphatic System May Play a Vital Role in the Pathogenesis of Hepatic Encephalopathy: A Narrative Review. Cells 2023; 12:cells12070979. [PMID: 37048052 PMCID: PMC10093707 DOI: 10.3390/cells12070979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 02/20/2023] [Accepted: 03/21/2023] [Indexed: 04/14/2023] Open
Abstract
Hepatic encephalopathy (HE) is a neurological complication of liver disease resulting in cognitive, psychiatric, and motor symptoms. Although hyperammonemia is a key factor in the pathogenesis of HE, several other factors have recently been discovered. Among these, the impairment of a highly organized perivascular network known as the glymphatic pathway seems to be involved in the progression of some neurological complications due to the accumulation of misfolded proteins and waste substances in the brain interstitial fluids (ISF). The glymphatic system plays an important role in the clearance of brain metabolic derivatives and prevents aggregation of neurotoxic agents in the brain ISF. Impairment of it will result in aggravated accumulation of neurotoxic agents in the brain ISF. This could also be the case in patients with liver failure complicated by HE. Indeed, accumulation of some metabolic by-products and agents such as ammonia, glutamine, glutamate, and aromatic amino acids has been reported in the human brain ISF using microdialysis technique is attributed to worsening of HE and correlates with brain edema. Furthermore, it has been reported that the glymphatic system is impaired in the olfactory bulb, prefrontal cortex, and hippocampus in an experimental model of HE. In this review, we discuss different factors that may affect the function of the glymphatic pathways and how these changes may be involved in HE.
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Affiliation(s)
- Ali Sepehrinezhad
- Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran 1449614535, Iran
- Neuroscience Research Center, Mashhad University of Medical Sciences, Mashhad 9919191778, Iran
| | - Fin Stolze Larsen
- Department of Gastroenterology and Hepatology, Rigshospitalet, Copenhagen University Hospital, 999017 Copenhagen, Denmark
| | | | - Ali Shahbazi
- Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran 1449614535, Iran
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran 1449614535, Iran
| | - Sajad Sahab Negah
- Neuroscience Research Center, Mashhad University of Medical Sciences, Mashhad 9919191778, Iran
- Shefa Neuroscience Research Center, Khatam Alanbia Hospital, Tehran 1449614535, Iran
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8
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Luo M, Xin RJ, Hu FR, Yao L, Hu SJ, Bai FH. Role of gut microbiota in the pathogenesis and therapeutics of minimal hepatic encephalopathy via the gut-liver-brain axis. World J Gastroenterol 2023; 29:144-156. [PMID: 36683714 PMCID: PMC9850958 DOI: 10.3748/wjg.v29.i1.144] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 11/23/2022] [Accepted: 12/14/2022] [Indexed: 01/04/2023] Open
Abstract
Minimal hepatic encephalopathy (MHE) is a frequent neurological and psychiatric complication of liver cirrhosis. The precise pathogenesis of MHE is complicated and has yet to be fully elucidated. Studies in cirrhotic patients and experimental animals with MHE have indicated that gut microbiota dysbiosis induces systemic inflammation, hyperammonemia, and endotoxemia, subsequently leading to neuroinflammation in the brain via the gut-liver-brain axis. Related mechanisms initiated by gut microbiota dysbiosis have significant roles in MHE pathogenesis. The currently available therapeutic strategies for MHE in clinical practice, including lactulose, rifaximin, probiotics, synbiotics, and fecal microbiota transplantation, exert their effects mainly by modulating gut microbiota dysbiosis. Microbiome therapies for MHE have shown promised efficacy and safety; however, several controversies and challenges regarding their clinical use deserve to be intensively discussed. We have summarized the latest research findings concerning the roles of gut microbiota dysbiosis in the pathogenesis of MHE via the gut-liver-brain axis as well as the potential mechanisms by which microbiome therapies regulate gut microbiota dysbiosis in MHE patients.
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Affiliation(s)
- Ming Luo
- Department of Gastroenterology, People’s Hospital of Ningxia Hui Autonomous Region, Yinchuan 750021, Ningxia Hui Autonomous Region, China
| | - Rui-Juan Xin
- Department of Gastroenterology, People’s Hospital of Ningxia Hui Autonomous Region, Yinchuan 750021, Ningxia Hui Autonomous Region, China
| | - Fang-Rui Hu
- Department of Gastroenterology, People’s Hospital of Ningxia Hui Autonomous Region, Yinchuan 750021, Ningxia Hui Autonomous Region, China
| | - Li Yao
- Department of Gastroenterology, People’s Hospital of Ningxia Hui Autonomous Region, Yinchuan 750021, Ningxia Hui Autonomous Region, China
| | - Sheng-Juan Hu
- Department of Gastroenterology, People’s Hospital of Ningxia Hui Autonomous Region, Yinchuan 750021, Ningxia Hui Autonomous Region, China
| | - Fei-Hu Bai
- Department of Gastroenterology, People’s Hospital of Ningxia Hui Autonomous Region, Yinchuan 750021, Ningxia Hui Autonomous Region, China
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9
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Zielińska M, Albrecht J, Popek M. Dysregulation of Astrocytic Glutamine Transport in Acute Hyperammonemic Brain Edema. Front Neurosci 2022; 16:874750. [PMID: 35733937 PMCID: PMC9207324 DOI: 10.3389/fnins.2022.874750] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 05/17/2022] [Indexed: 11/13/2022] Open
Abstract
Acute liver failure (ALF) impairs ammonia clearance from blood, which gives rise to acute hyperammonemia and increased ammonia accumulation in the brain. Since in brain glutamine synthesis is the only route of ammonia detoxification, hyperammonemia is as a rule associated with increased brain glutamine content (glutaminosis) which correlates with and contributes along with ammonia itself to hyperammonemic brain edema-associated with ALF. This review focuses on the effects of hyperammonemia on the two glutamine carriers located in the astrocytic membrane: Slc38a3 (SN1, SNAT3) and Slc7a6 (y + LAT2). We emphasize the contribution of the dysfunction of either of the two carriers to glutaminosis- related aspects of brain edema: retention of osmotically obligated water (Slc38a3) and induction of oxidative/nitrosative stress (Slc7a6). The changes in glutamine transport link glutaminosis- evoked mitochondrial dysfunction to oxidative-nitrosative stress as formulated in the “Trojan Horse” hypothesis.
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10
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Severe Acute Hepatic Dysfunction Induced by Ammonium Acetate Treatment Results in Choroid Plexus Swelling and Ventricle Enlargement in the Brain. Int J Mol Sci 2022; 23:ijms23042010. [PMID: 35216129 PMCID: PMC8879736 DOI: 10.3390/ijms23042010] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 02/08/2022] [Accepted: 02/10/2022] [Indexed: 02/04/2023] Open
Abstract
Hepatic encephalopathy is a major cause of liver failure. However, the pathophysiological role of ventricle enlargement in brain edema remains unclear. Here, we used an acute hepatic encephalopathy mouse model to examine the sequential pathological changes in the brain associated with this condition. We collected tissue samples from experimental animals treated with ammonium acetate at 3 and 24 h post-injection. Despite the normalization of the animal’s ammonia levels, samples taken at 24 h after injection exhibited distinct enlargement of lateral ventricles. The choroid plexus samples obtained at 3 h post-ammonium acetate treatment indicated enlargement; however, this swelling was reduced at the later timepoint. The aquaporin-1 proteins that regulate the choroid plexus were localized both in the apical membrane and the cytoplasm of the epithelia in the control; however, they translocated to the apical membranes of the epithelia in response to ammonia treatment. Therefore, severe acute hepatic encephalopathy induced by ammonium acetate administration caused enlargement of the ventricles, through swelling of the choroid plexus and aquaporin-1 transport and aggregation within the apical membranes.
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11
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Martin MDGM, Paes VR, Cardoso EF, Neto CEBP, Kanamura CT, Leite CDC, Otaduy MCG, Monteiro RADA, Mauad T, da Silva LFF, Castro LHM, Saldiva PHN, Dolhnikoff M, Duarte-Neto AN. Postmortem brain 7T MRI with minimally invasive pathological correlation in deceased COVID-19 subjects. Insights Imaging 2022; 13:7. [PMID: 35032223 PMCID: PMC8760871 DOI: 10.1186/s13244-021-01144-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 12/14/2021] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Brain abnormalities are a concern in COVID-19, so we used minimally invasive autopsy (MIA) to investigate it, consisting of brain 7T MR and CT images and tissue sampling via transethmoidal route with at least three fragments: the first one for reverse transcription polymerase chain reaction (RT-PCR) analysis and the remaining fixed and stained with hematoxylin and eosin. Two mouse monoclonal anti-coronavirus (SARS-CoV-2) antibodies were employed in immunohistochemical (IHC) reactions. RESULTS Seven deceased COVID-19 patients underwent MIA with brain MR and CT images, six of them with tissue sampling. Imaging findings included infarcts, punctate brain hemorrhagic foci, subarachnoid hemorrhage and signal abnormalities in the splenium, basal ganglia, white matter, hippocampi and posterior cortico-subcortical. Punctate brain hemorrhage was the most common finding (three out of seven cases). Brain histological analysis revealed reactive gliosis, congestion, cortical neuron eosinophilic degeneration and axonal disruption in all six cases. Other findings included edema (5 cases), discrete perivascular hemorrhages (5), cerebral small vessel disease (3), perivascular hemosiderin deposits (3), Alzheimer type II glia (3), abundant corpora amylacea (3), ischemic foci (1), periventricular encephalitis foci (1), periventricular vascular ectasia (1) and fibrin thrombi (1). SARS-CoV-2 RNA was detected with RT-PCR in 5 out of 5 and IHC in 6 out 6 patients (100%). CONCLUSIONS Despite limited sampling, MIA was an effective tool to evaluate underlying pathological brain changes in deceased COVID-19 patients. Imaging findings were varied, and pathological features corroborated signs of hypoxia, alterations related to systemic critically ill and SARS-CoV-2 brain invasion.
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Affiliation(s)
- Maria da Graça Morais Martin
- Instituto de Radiologia, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, LIM44, Travessa da Rua Dr. Ovídio Pires de Campos, 75, São Paulo, SP, 05403-010, Brazil.
| | - Vitor Ribeiro Paes
- Departamento de Patologia, Faculdade de Medicina FMUSP, Universidade de São Paulo, São Paulo, Brazil
| | - Ellison Fernando Cardoso
- Instituto de Radiologia, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, LIM44, Travessa da Rua Dr. Ovídio Pires de Campos, 75, São Paulo, SP, 05403-010, Brazil
| | | | | | - Claudia da Costa Leite
- Departamento de Radiologia e Oncologia, Faculdade de Medicina, Universidade de São Paulo, LIM 44 HCFMUSP, São Paulo, Brazil
| | - Maria Concepcion Garcia Otaduy
- Instituto de Radiologia, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, LIM44, Travessa da Rua Dr. Ovídio Pires de Campos, 75, São Paulo, SP, 05403-010, Brazil
| | | | - Thais Mauad
- Departamento de Patologia, Faculdade de Medicina FMUSP, Universidade de São Paulo, São Paulo, Brazil
| | - Luiz Fernando Ferraz da Silva
- Departamento de Patologia, Faculdade de Medicina FMUSP, Universidade de São Paulo, Servico de Verificaçao de Óbitos de São Paulo (SVO), São Paulo, Brazil
| | | | | | - Marisa Dolhnikoff
- Departamento de Patologia, Faculdade de Medicina FMUSP, Universidade de São Paulo, São Paulo, Brazil
| | - Amaro Nunes Duarte-Neto
- Departamento de Patologia, Faculdade de Medicina FMUSP, Universidade de São Paulo, São Paulo, Brazil
- Instituto Adolfo Lutz, São Paulo, Brazil
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12
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Sen K, Whitehead M, Castillo Pinto C, Caldovic L, Gropman A. Fifteen years of urea cycle disorders brain research: Looking back, looking forward. Anal Biochem 2022; 636:114343. [PMID: 34637785 PMCID: PMC8671367 DOI: 10.1016/j.ab.2021.114343] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/13/2021] [Accepted: 08/17/2021] [Indexed: 01/03/2023]
Abstract
Urea cycle disorders (UCD) are inherited diseases resulting from deficiency in one of six enzymes or two carriers that are required to remove ammonia from the body. UCD may be associated with neurological damage encompassing a spectrum from asymptomatic/mild to severe encephalopathy, which results in most cases from Hyperammonemia (HA) and elevation of other neurotoxic intermediates of metabolism. Electroencephalography (EEG), Magnetic resonance imaging (MRI) and Proton Magnetic resonance spectroscopy (MRS) are noninvasive measures of brain function and structure that can be used during HA to guide management and provide prognostic information, in addition to being research tools to understand the pathophysiology of UCD associated brain injury. The Urea Cycle Rare disorders Consortium (UCDC) has been invested in research to understand the immediate and downstream effects of hyperammonemia (HA) on brain using electroencephalogram (EEG) and multimodal brain MRI to establish early patterns of brain injury and to track recovery and prognosis. This review highlights the evolving knowledge about the impact of UCD and HA in particular on neurological injury and recovery and use of EEG and MRI to study and evaluate prognostic factors for risk and recovery. It recognizes the work of others and discusses the UCDC's prior work and future research priorities.
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Affiliation(s)
- Kuntal Sen
- Division of Neurogenetics and Neurodevelopmental Pediatrics, Children's National Hospital, Washington D.C., United States
| | - Matthew Whitehead
- Division of Radiology, Children's National Hospital, Washington D.C., United States
| | | | - Ljubica Caldovic
- Childrens' Research Institute, Children's National Hospital, Washington D.C., United States
| | - Andrea Gropman
- Division of Neurogenetics and Neurodevelopmental Pediatrics, Children's National Hospital, Washington D.C., United States.
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13
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Saul Brusilow: Understanding and treating diseases of ammonia toxicity. Anal Biochem 2022; 636:114478. [PMID: 34808107 DOI: 10.1016/j.ab.2021.114478] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 10/05/2021] [Accepted: 11/16/2021] [Indexed: 02/08/2023]
Abstract
This article reviews the scientific career and accomplishments of the late Dr. Saul Brusilow, Professor of Pediatrics at Johns Hopkins. Dr. Brusilow's career was focused on diseases involving hyperammonemia. He and his colleagues developed a set of drugs that could lower ammonia levels in patients with genetic disorders of the urea cycle by providing alternative pathways for the synthesis of excretable nitrogenous molecules. Those drugs and their derivatives represent one of the earliest and most successful drug therapies for genetic diseases. Turning their attention to brain swelling caused by liver disease, Dr. Brusilow and colleagues developed the Osmotic Gliopathy Hypothesis to help explain the mechanism of ammonia toxicity, postulating that high ammonia drives glutamine synthetase in astrocytes to produce elevated levels of glutamine that act as a potent osmolyte, drawing water into the cell and causing cerebral edema. This hypothesis suggests that inhibiting glutamine synthetase with its well-characterized inhibitor, methionine sulfoximine, might prove therapeutic in cases of hepatic encephalopathy, a conclusion supported by their subsequent studies in animals. But although the drugs developed to treat hyperammonemia resulting from urea cycle disorders were successfully developed and approved by the FDA, the compound suggested as a treatment for hepatic encephalopathy was unable to attract sufficient interest and investment to be tested for use in humans.
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14
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Wang Q, Guan K, Lv Y, Zhang Y, Yu Z, Kan Q. Disturbance of hepatocyte growth and metabolism in a hyperammonemia microenvironment. Arch Biochem Biophys 2021; 716:109109. [PMID: 34932992 DOI: 10.1016/j.abb.2021.109109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 12/14/2021] [Accepted: 12/16/2021] [Indexed: 11/24/2022]
Abstract
BACKGROUND We found through previous research that hyperammonemia can cause secondary liver damage. However, whether hepatocytes are target cells of ammonia toxicity and whether hyperammonemia affects hepatocyte metabolism remain unknown. AIMS The purpose of the current study is to examine whether the hepatocyte is a specific target cell of ammonia toxicity and whether hyperammonemia can interfere with hepatocyte metabolism. METHODS Cell viability and apoptosis were analyzed in primary hepatocytes and other cells that had been exposed to ammonium chloride. Western blotting was adopted to examine the expression of proteins related to ammonia transport. We also established a metabolomics method based on gas chromatography-mass spectrometry to understand the characteristics of the hepatocyte metabolic spectrum in a hyperammonemia microenvironment, to screen and identify differential metabolites, and to determine the differential metabolic pathway. Different technologies were used to verify the differential metabolic pathways. RESULTS Hepatocytes are target cells of ammonia toxicity. The mechanism is related to the ammonia transporter. Hyperammonemia interferes with hepatocyte metabolism, which leads to TCA cycle, urea cycle, and RNA synthesis disorder. CONCLUSIONS This study demonstrates that hepatocyte growth and metabolism are disturbed in a hyperammonemia microenvironment, which further deteriorates hepatocyte function.
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Affiliation(s)
- Qiongye Wang
- Departments of Infectious Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Kelei Guan
- Department of Pharmacology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yuanjun Lv
- Department of Respiratory. the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yingxuan Zhang
- Department of Hepatobiliary and Pancreatic Surgery. the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Zujiang Yu
- Departments of Infectious Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.
| | - Quancheng Kan
- Department of Pharmacology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.
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15
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Kim YK, Song J. Therapeutic Applications of Resveratrol in Hepatic Encephalopathy through Its Regulation of the Microbiota, Brain Edema, and Inflammation. J Clin Med 2021; 10:jcm10173819. [PMID: 34501267 PMCID: PMC8432232 DOI: 10.3390/jcm10173819] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 08/22/2021] [Accepted: 08/24/2021] [Indexed: 02/07/2023] Open
Abstract
Hepatic encephalopathy is a common complication in patients with liver cirrhosis and portosystemic shunting. Patients with hepatic encephalopathy present a variety of clinical features, including neuropsychiatric manifestations, cognitive dysfunction, impaired gut barrier function, hyperammonemia, and chronic neuroinflammation. These pathogeneses have been linked to various factors, including ammonia-induced oxidative stress, neuronal cell death, alterations in the gut microbiome, astrocyte swelling, and blood-brain barrier disruptions. Many researchers have focused on identifying novel therapeutics and prebiotics in the hope of improving the treatment of these conditions. Resveratrol is a natural polyphenic compound and is known to exert several pharmacological effects, including antioxidant, anti-inflammatory, and neuroprotective activities. Recent studies suggest that resveratrol contributes to improving the neuropathogenic effects of liver failure. Here, we review the current evidence describing resveratrol's effects in neuropathogenesis and its impact on the gut-liver axis relating to hepatic encephalopathy. We highlight the hypothesis that resveratrol exerts diverse effects in hepatic encephalopathy and suggest that these effects are likely mediated by changes to the gut microbiota, brain edema, and neuroinflammation.
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Affiliation(s)
- Young-Kook Kim
- Department of Biochemistry, Chonnam National University Medical School, Hwasun 58128, Jeollanam-do, Korea;
| | - Juhyun Song
- Department of Anatomy, Chonnam National University Medical School, Hwasun 58128, Jeollanam-do, Korea
- Correspondence: ; Tel.: +82-61-379-2706; Fax: +82-61-375-5834
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16
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Devriendt N, Paepe D, Serrano G, Vandenabeele S, Stock E, Van Acker L, de Rooster H. Plasma amino acid profiles in dogs with closed extrahepatic portosystemic shunts are only partially improved 3 months after successful gradual attenuation. J Vet Intern Med 2021; 35:1347-1354. [PMID: 33949730 PMCID: PMC8162604 DOI: 10.1111/jvim.16135] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 04/07/2021] [Accepted: 04/14/2021] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Dogs with portosystemic shunts have an altered blood amino acid profile, with an abnormal branched-chained amino acid (BCAA)-to-aromatic amino acid (AAA) ratio being the most common abnormality. Different liver diseases have distinctive amino acid profiles. OBJECTIVES Determine the changes in plasma amino acid profiles in dogs with extrahepatic portosystemic shunts (EHPSS) from diagnosis to complete closure. ANIMALS Ten client-owned dogs with EHPSS closed after surgical attenuation. METHODS Prospective cohort study. Medical treatment was instituted in dogs diagnosed with EHPSS. At least 4 weeks later, gradual surgical attenuation was performed. Three months postoperatively, EHPSS closure was confirmed by transsplenic portal scintigraphy. Clinical signs were scored and blood was taken before institution of medical treatment, at time of surgery, and 3 months postoperatively. At the end of the study, the plasma amino acid profiles were analyzed in batch. RESULTS The median BCAA-to-AAA ratio was extremely low (0.6) at time of diagnosis and remained low (0.5) at time of surgery, despite the fact that median neurological score significantly improved from 22 to 2 after starting medical treatment (P = .04). Three months after surgical attenuation, a significantly higher BCAA-to-AAA ratio (1.5) was observed (P < .001). CONCLUSIONS AND CLINICAL IMPORTANCE Medical treatment does not improve the BCAA-to-AAA ratio in dogs with EHPSS, despite substantial clinical improvement. Although the ratio significantly increased after EHPSS closure, it was still indicative of moderate to severe hepatic dysfunction in all dogs.
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Affiliation(s)
- Nausikaa Devriendt
- Small Animal Department, Faculty of Veterinary MedicineGhent UniversityMerelbekeBelgium
| | - Dominique Paepe
- Small Animal Department, Faculty of Veterinary MedicineGhent UniversityMerelbekeBelgium
| | - Gonçalo Serrano
- Small Animal Department, Faculty of Veterinary MedicineGhent UniversityMerelbekeBelgium
| | - Sophie Vandenabeele
- Small Animal Department, Faculty of Veterinary MedicineGhent UniversityMerelbekeBelgium
| | - Emmelie Stock
- Department of Medical Imaging of Domestic Animals and Small Animal Orthopaedics, Faculty of Veterinary MedicineGhent UniversityMerelbekeBelgium
| | - Lisa Van Acker
- Small Animal Department, Faculty of Veterinary MedicineGhent UniversityMerelbekeBelgium
| | - Hilde de Rooster
- Small Animal Department, Faculty of Veterinary MedicineGhent UniversityMerelbekeBelgium
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17
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McCann MS, Maguire-Zeiss KA. Environmental toxicants in the brain: A review of astrocytic metabolic dysfunction. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2021; 84:103608. [PMID: 33556584 DOI: 10.1016/j.etap.2021.103608] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 01/24/2021] [Accepted: 01/29/2021] [Indexed: 06/12/2023]
Abstract
Exposure to environmental toxicants is linked to long-term adverse outcomes in the brain and involves the dysfunction of glial and neuronal cells. Astrocytes, the most numerous cell type, are increasingly implicated in the pathogenesis of many diseases of the central nervous system, including neurodegenerative diseases. Astrocytes are critical for proper brain function in part due to their robust antioxidant and unique metabolic capabilities. Additionally, astrocytes are positioned both at the blood-brain barrier, where they are the primary responders to xenobiotic penetrance of the CNS, and at synapses where they are in close contact with neurons and synaptic machinery. While exposure to several classes of environmental toxicants, including chlorinated and fluorinated compounds, and trace metals, have been implicated in neurodegenerative diseases, their impact on astrocytes represents an important and growing field of research. Here, we review existing literature focused on the impact of a range of synthetic compounds on astrocytic function. We focus specifically on perturbed metabolic processes in response to these compounds and consider how perturbation of these pathways impacts disease pathogenesis.
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Affiliation(s)
- Mondona S McCann
- Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, DC, 20057, United States.
| | - Kathleen A Maguire-Zeiss
- Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, DC, 20057, United States; Department of Neuroscience, Georgetown University Medical Center, Washington, DC, 20057, United States
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18
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Pathania A, Rawat A, Dahiya SS, Dhanda S, Barnwal RP, Baishya B, Sandhir R. 1H NMR-Based Metabolic Signatures in the Liver and Brain in a Rat Model of Hepatic Encephalopathy. J Proteome Res 2020; 19:3668-3679. [PMID: 32660248 DOI: 10.1021/acs.jproteome.0c00165] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Hepatic encephalopathy (HE) is a debilitating neuropsychiatric complication associated with acute and chronic liver failure. It is characterized by diverse symptoms with variable severity that includes cognitive and motor deficits. The aim of the study is to assess metabolic alterations in the brain and liver using nuclear magnetic resonance (NMR) spectroscopy and subsequent multivariate analyses to characterize metabolic signatures associated with HE. HE was developed by bile duct ligation (BDL) that resulted in hepatic dysfunctions and cirrhosis as shown by liver function tests. Metabolic profiles from control and BDL rats indicated increased levels of lactate, branched-chain amino acids (BCAAs), glutamate, and choline in the liver, whereas levels of glucose, phenylalanine, and pyridoxine were decreased. In brain, the levels of lactate, acetate, succinate, citrate, and malate were increased, while glucose, creatine, isoleucine, leucine, and proline levels were decreased. Furthermore, neurotransmitters such as glutamate and GABA were increased, whereas choline and myo-inositol were decreased. The alterations in neurotransmitter levels resulted in cognitive and motor defects in BDL rats. A significant correlation was found among alterations in NAA/choline, choline/creatine, and NAA/creatine with behavioral deficits. Thus, the data suggests impairment in metabolic pathways such as the tricarboxylic acid (TCA) cycle, glycolysis, and ketogenesis in the liver and brain of animals with HE. The study highlights that metabolic signatures could be potential markers to monitor HE progression and to assess therapeutic interventions.
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Affiliation(s)
- Anjana Pathania
- Department of Biochemistry, Basic Medical Science Block-II, Panjab University, Sector-25, Chandigarh 160014, India
| | - Atul Rawat
- Department of Surgery, IU Health Comprehensive Wound Centre, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, Indiana 46202, United States.,Centre for Biomedical Magnetic Resonance (CBMR), SGPGIMS Campus, Lucknow, Uttar Pradesh 226014, India
| | - Sitender Singh Dahiya
- Department of Biochemistry, Basic Medical Science Block-II, Panjab University, Sector-25, Chandigarh 160014, India
| | - Saurabh Dhanda
- Department of Biochemistry, Dr. Rajendra Prasad Government Medical College, Kangra at Tanda, Himachal Pradesh 176001, India
| | | | - Bikash Baishya
- Centre for Biomedical Magnetic Resonance (CBMR), SGPGIMS Campus, Lucknow, Uttar Pradesh 226014, India
| | - Rajat Sandhir
- Department of Biochemistry, Basic Medical Science Block-II, Panjab University, Sector-25, Chandigarh 160014, India
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19
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Tran TT, Wei K, Cole S, Mena E, Csete M, King KS. Brain MR Spectroscopy Markers of Encephalopathy Due to Nonalcoholic Steatohepatitis. J Neuroimaging 2020; 30:697-703. [PMID: 32705733 DOI: 10.1111/jon.12728] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 04/22/2020] [Accepted: 05/06/2020] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE In hepatic encephalopathy (HE), osmotic stressors promoting brain edema result in a compensatory drop in the astrocyte metabolite myo-inositol (mI). Identifying differences between nonalcoholic steatohepatitis (NASH) with and without HE and healthy controls using proton magnetic resonance spectroscopy (MRS) and evaluating hypoalbuminemia and hyperammonemia as osmotic stressors that predict the reduction of mI allow further understanding of mechanisms that promote brain edema in HE. The aim of this study was to assess brain edema in HE using characteristic MRS markers and serum albumin. METHODS We evaluated between group differences among 19 NASH cirrhosis without HE (Crhs-HE) (age = 63 ± 8.7), 9 NASH cirrhosis with HE (Crhs+HE) (age = 63 ± 9.2), and 16 controls (age = 57.8 ± 11.7) using 1 H MRS. Glutamine (Gln/tCr) and serum albumin were evaluated as predictors of myo-inositol (mI/tCr) using linear regression. Statistical significance was set at P < .05 with adjustment for multiple comparisons. RESULTS Brain mI/tCr was decreased, and Gln/tCr increased in Crhs+HE compared to Crhs-HE and controls in both brain regions (P < .001 for all). Evaluated together as joint predictors, serum albumin but not Gln/tCr significantly predicted mI/tCr in GM (P = .02 and P = .2, respectively) and PWM (P = .01 and P = .1, respectively). CONCLUSION Low mI/tCr and increased Gln/tCr were characteristics of Crhs+HE. Low serum albumin was the strongest predictor of brain osmotic stress indicated by reduced mI/tCr, with no residual independent association seen for brain Gln/tCr concentration. This suggests that hypoalbuminemia in chronic liver disease may promote brain edema in HE.
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Affiliation(s)
| | - Ke Wei
- HMRI Imaging Center, Pasadena, CA
| | | | - Edward Mena
- California Liver Research Institute, Pasadena, CA
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20
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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: 34] [Impact Index Per Article: 8.5] [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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21
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Taherian M, Norenberg MD, Panickar KS, Shamaladevi N, Ahmad A, Rahman P, Jayakumar AR. Additive Effect of Resveratrol on Astrocyte Swelling Post-exposure to Ammonia, Ischemia and Trauma In Vitro. Neurochem Res 2020; 45:1156-1167. [PMID: 32166573 DOI: 10.1007/s11064-020-02997-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 12/12/2019] [Accepted: 02/22/2020] [Indexed: 12/16/2022]
Abstract
Swelling of astrocytes represents a major component of the brain edema associated with many neurological conditions, including acute hepatic encephalopathy (AHE), traumatic brain injury (TBI) and ischemia. It has previously been reported that exposure of cultured astrocytes to ammonia (a factor strongly implicated in the pathogenesis of AHE), oxygen/glucose deprivation, or to direct mechanical trauma results in an increase in cell swelling. Since dietary polyphenols have been shown to exert a protective effect against cell injury, we examined whether resveratrol (RSV, 3,5,4'-trihydroxy-trans-stilbene, a stilbenoid phenol), has a protective effect on astrocyte swelling following its exposure to ammonia, oxygen-glucose deprivation (OGD), or trauma in vitro. Ammonia increased astrocyte swelling, and pre- or post-treatment of astrocytes with 10 and 25 µM RSV displayed an additive effect, while 5 µM did not prevent the effect of ammonia. However, pre-treatment of astrocytes with 25 µM RSV slightly, but significantly, reduced the trauma-induced astrocyte swelling at earlier time points (3 h), while post-treatment had no significant effect on the trauma-induced cell swelling at the 3 h time point. Instead, pre- or post-treatment of astrocytes with 25 µM RSV had an additive effect on trauma-induced astrocyte swelling. Further, pre- or post-treatment of astrocytes with 5 or 10 µM RSV had no significant effect on trauma-induced astrocyte swelling. When 5 or 10 µM RSV were added prior to, or during the process of OGD, as well as post-OGD, it caused a slight, but not statistically significant decline in cell swelling. However, when 25 µM RSV was added during the process of OGD, as well as after the cells were returned to normal condition (90 min period), such treatment showed an additive effect on the OGD-induced astrocyte swelling. Noteworthy, a higher concentration of RSV (25 µM) exhibited an additive effect on levels of phosphorylated forms of ERK1/2, and p38MAPK, as well as an increased activity of the Na+-K+-Cl- co-transporter-1 (NKCC1), factors known to induce astrocytes swelling, when the cells were treated with ammonia or after trauma or ischemia. Further, inhibition of ERK1/2, and p38MAPK diminished the RSV-induced exacerbation of cell swelling post-ammonia, trauma and OGD treatment. These findings strongly suggest that treatment of cultured astrocytes with RSV enhanced the ammonia, ischemia and trauma-induced cell swelling, likely through the exacerbation of intercellular signaling kinases and ion transporters. Accordingly, caution should be exercised when using RSV for the treatment of these neurological conditions, especially when brain edema is also suspected.
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Affiliation(s)
- Mehran Taherian
- General Medical Research, Neuropathology Section, R&D Service, Veterans Affairs Medical Center, Miami, FL, 33125, USA
| | - Michael D Norenberg
- Department of Pathology, University of Miami School of Medicine, Miami, FL, USA.,Department of Biochemistry & Molecular Biology, University of Miami School of Medicine, Miami, FL, USA.,Department of Neurology and Neurological Surgery, University of Miami School of Medicine, Miami, FL, USA
| | - Kiran S Panickar
- General Medical Research, Neuropathology Section, R&D Service, Veterans Affairs Medical Center, Miami, FL, 33125, USA
| | | | - Anis Ahmad
- Department of Radiation Oncology, Sylvester Cancer Center, University of Miami School of Medicine, Miami, FL, USA
| | - Purbasha Rahman
- General Medical Research, Neuropathology Section, R&D Service, Veterans Affairs Medical Center, Miami, FL, 33125, USA.,Department of Microbiology and Immunology, University of Miami, Coral Cables, Miami, FL, USA
| | - Arumugam R Jayakumar
- General Medical Research, Neuropathology Section, R&D Service, Veterans Affairs Medical Center, Miami, FL, 33125, USA. .,South Florida VA Foundation for Research and Education Inc, Veterans Affairs Medical Center, Miami, FL, 33125, USA. .,General Medical Research, Neuropathology Section, R&D Service, Veterans Affairs Medical Center, 1201 NW 16th St, Res-151, Room 314, Miami, FL, USA.
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22
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Liotta EM, Kimberly WT. Cerebral edema and liver disease: Classic perspectives and contemporary hypotheses on mechanism. Neurosci Lett 2020; 721:134818. [PMID: 32035166 DOI: 10.1016/j.neulet.2020.134818] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 02/01/2020] [Accepted: 02/03/2020] [Indexed: 02/07/2023]
Abstract
Liver disease is a growing public health concern. Hepatic encephalopathy, the syndrome of brain dysfunction secondary to liver disease, is a frequent complication of both acute and chronic liver disease and cerebral edema (CE) is a key feature. While altered ammonia metabolism is a key contributor to hepatic encephalopathy and CE in liver disease, there is a growing appreciation that additional mechanisms contribute to CE. In this review we will begin by presenting three classic perspectives that form a foundation for a discussion of CE in liver disease: 1) CE is unique to acute liver failure, 2) CE in liver disease is only cytotoxic, and 3) CE in liver disease is primarily an osmotically mediated consequence of ammonia and glutamine metabolism. We will present each classic perspective along with more recent observations that call in to question that classic perspective. After highlighting these areas of debate, we will explore the leading contemporary mechanisms hypothesized to contribute to CE during liver disease.
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Affiliation(s)
- Eric M Liotta
- Northwestern University-Feinberg School of Medicine, Department of Neurology, United States; Northwestern University-Feinberg School of Medicine, Department of Surgery, Division of Organ Transplantation, United States; Northwestern University Transplant Outcomes Research Collaboration, United States.
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23
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Dehghani M, Kunz N, Lei H. Diffusion behavior of cerebral metabolites of congenital portal systemic shunt mice assessed noninvasively by diffusion-weighted 1 H magnetic resonance spectroscopy. NMR IN BIOMEDICINE 2020; 33:e4198. [PMID: 31765073 DOI: 10.1002/nbm.4198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 08/27/2019] [Accepted: 09/13/2019] [Indexed: 06/10/2023]
Abstract
Diffusion-weighted 1 H-MRS (DW-MRS) allows for noninvasive investigation of the cellular compartmentalization of cerebral metabolites. DW-MRS applied to the congenital portal systemic shunt (PSS) mouse brain may provide specific insight into alterations of cellular restrictions associated with PSS in humans. At 14.1 T, adult male PSS and their age-matched healthy (Ctrl) mice were studied using DW-MRS covering b-values ranging from 0 to 45 ms/μm2 to determine the diffusion behavior of abundant metabolites. The remarkable sensitivity and spectral resolution, in combination with very high diffusion weighting, allowed for precise measurement of the diffusion properties of endogenous N-acetyl-aspartate, total creatine, myo-inositol, total choline with extension to glutamine and glutamate in mouse brains, in vivo. Most metabolites had comparable diffusion properties in PSS and Ctrl mice, suggesting that intracellular distribution space for these metabolites was not affected in the model. The slightly different diffusivity of the slow decaying component of taurine (0.015 ± 0.003 μm2 /ms in PSS vs 0.021 ± 0.002 μm2 /ms in Ctrl, P < 0.05) might support a cellular redistribution of taurine in the PSS mouse brain.
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Affiliation(s)
- Masoumeh Dehghani
- Laboratory of Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Department of Psychiatry, McGill University, Montreal, Canada
| | - Nicolas Kunz
- Center for Biomedical Imaging (CIBM), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Hongxia Lei
- Center for Biomedical Imaging (CIBM), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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24
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Guazzelli PA, Cittolin-Santos GF, Meira-Martins LA, Grings M, Nonose Y, Lazzarotto GS, Nogara D, da Silva JS, Fontella FU, Wajner M, Leipnitz G, Souza DO, de Assis AM. Acute Liver Failure Induces Glial Reactivity, Oxidative Stress and Impairs Brain Energy Metabolism in Rats. Front Mol Neurosci 2020; 12:327. [PMID: 31998076 PMCID: PMC6968792 DOI: 10.3389/fnmol.2019.00327] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 12/18/2019] [Indexed: 01/02/2023] Open
Abstract
Acute liver failure (ALF) implies a severe and rapid liver dysfunction that leads to impaired liver metabolism and hepatic encephalopathy (HE). Recent studies have suggested that several brain alterations such as astrocytic dysfunction and energy metabolism impairment may synergistically interact, playing a role in the development of HE. The purpose of the present study is to investigate early alterations in redox status, energy metabolism and astrocytic reactivity of rats submitted to ALF. Adult male Wistar rats were submitted either to subtotal hepatectomy (92% of liver mass) or sham operation to induce ALF. Twenty-four hours after the surgery, animals with ALF presented higher plasmatic levels of ammonia, lactate, ALT and AST and lower levels of glucose than the animals in the sham group. Animals with ALF presented several astrocytic morphological alterations indicating astrocytic reactivity. The ALF group also presented higher mitochondrial oxygen consumption, higher enzymatic activity and higher ATP levels in the brain (frontoparietal cortex). Moreover, ALF induced an increase in glutamate oxidation concomitant with a decrease in glucose and lactate oxidation. The increase in brain energy metabolism caused by astrocytic reactivity resulted in augmented levels of reactive oxygen species (ROS) and Poly [ADP-ribose] polymerase 1 (PARP1) and a decreased activity of the enzymes superoxide dismutase and glutathione peroxidase (GSH-Px). These findings suggest that in the early stages of ALF the brain presents a hypermetabolic state, oxidative stress and astrocytic reactivity, which could be in part sustained by an increase in mitochondrial oxidation of glutamate.
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Affiliation(s)
- Pedro Arend Guazzelli
- Post-graduate Program in Biological Sciences: Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil.,Department of Biochemistry, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil
| | - Giordano Fabricio Cittolin-Santos
- Post-graduate Program in Biological Sciences: Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil.,Department of Biochemistry, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil
| | - Leo Anderson Meira-Martins
- Post-graduate Program in Biological Sciences: Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil
| | - Mateus Grings
- Post-graduate Program in Biological Sciences: Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil
| | - Yasmine Nonose
- Post-graduate Program in Biological Sciences: Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil
| | - Gabriel S Lazzarotto
- Post-graduate Program in Biological Sciences: Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil
| | - Daniela Nogara
- Department of Biochemistry, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil
| | - Jussemara S da Silva
- Post-graduate Program in Biological Sciences: Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil
| | - Fernanda U Fontella
- Post-graduate Program in Biological Sciences: Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil
| | - Moacir Wajner
- Post-graduate Program in Biological Sciences: Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil.,Department of Biochemistry, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil
| | - Guilhian Leipnitz
- Post-graduate Program in Biological Sciences: Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil
| | - Diogo O Souza
- Post-graduate Program in Biological Sciences: Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil.,Department of Biochemistry, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil
| | - Adriano Martimbianco de Assis
- Post-graduate Program in Biological Sciences: Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, Brazil.,Post-graduate Program in Health and Behavior, Health Sciences Centre, Universidade Católica de Pelotas-UCPel, Pelotas, Brazil
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25
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Wang T, Suzuki K, Kakisaka K, Onodera M, Sawara K, Takikawa Y. L-carnitine prevents ammonia-induced cytotoxicity and disturbances in intracellular amino acid levels in human astrocytes. J Gastroenterol Hepatol 2019; 34:1249-1255. [PMID: 30278111 DOI: 10.1111/jgh.14497] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 09/04/2018] [Accepted: 09/19/2018] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND AIM L-carnitine (L-CA) has been used therapeutically to treat hepatic encephalopathy with hyperammonemia, but the mechanism by which L-CA contributes to ammonia detoxification in the brain is still unclear. Thus, the cytotoxicity and changes in intracellular amino acids (AAs) in astrocytes with hyperammonemia following L-CA administration were studied. METHODS Human astrocytes were treated with ammonium chloride (NH4 Cl), L-CA or a mixture of NH4 Cl, and L-CA under defined conditions. Total intracellular reactive oxygen species and lactate dehydrogenase leakage were measured following different treatment periods. The intracellular levels of AAs in astrocytes were determined using metabolomic analysis. RESULTS Intracellular total reactive oxygen species and lactate dehydrogenase leakage were significantly increased after treatment with NH4 Cl. In contrast, co-treatment with L-CA significantly inhibited the cytotoxic effects of NH4 Cl. The intracellular levels of almost all AAs involving glutamine and branched-chain AAs (BCAAs) were significantly increased in the NH4 Cl-treated cells compared with in the control cells; these changes in BCAA levels were reduced with L-CA co-treatment. Additionally, the level of 3-methyl-2-oxovaleric acid, which is a metabolite from isoleucine and plays a critical role in neurological damage, was significantly increased in the NH4 Cl-treated cells, but this metabolite was significantly decreased with L-CA co-treatment. CONCLUSION L-CA protects human astrocytes from ammonia-induced acute cytotoxic effects and the increased intracellular levels of glutamine and BCAAs.
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Affiliation(s)
- Ting Wang
- Division of Hepatology, Department of Internal Medicine, Iwate Medical University, Morioka, Japan
| | - Kazuyuki Suzuki
- Division of Hepatology, Department of Internal Medicine, Iwate Medical University, Morioka, Japan.,Department of Nutritional Science, Morioka University, Takizawa, Japan
| | - Keisuke Kakisaka
- Division of Hepatology, Department of Internal Medicine, Iwate Medical University, Morioka, Japan
| | - Mio Onodera
- Division of Hepatology, Department of Internal Medicine, Iwate Medical University, Morioka, Japan
| | - Kei Sawara
- Division of Hepatology, Department of Internal Medicine, Iwate Medical University, Morioka, Japan
| | - Yasuhiro Takikawa
- Division of Hepatology, Department of Internal Medicine, Iwate Medical University, Morioka, Japan
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26
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Cudalbu C, Taylor-Robinson SD. Brain Edema in Chronic Hepatic Encephalopathy. J Clin Exp Hepatol 2019; 9:362-382. [PMID: 31360029 PMCID: PMC6637228 DOI: 10.1016/j.jceh.2019.02.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 01/15/2019] [Accepted: 02/06/2019] [Indexed: 02/07/2023] Open
Abstract
Brain edema is a common feature associated with hepatic encephalopathy (HE). In patients with acute HE, brain edema has been shown to play a crucial role in the associated neurological deterioration. In chronic HE, advanced magnetic resonance imaging (MRI) techniques have demonstrated that low-grade brain edema appears also to be an important pathological feature. This review explores the different methods used to measure brain edema ex vivo and in vivo in animal models and in humans with chronic HE. In addition, an in-depth description of the main studies performed to date is provided. The role of brain edema in the neurological alterations linked to HE and whether HE and brain edema are the manifestations of the same pathophysiological mechanism or two different cerebral manifestations of brain dysfunction in liver disease are still under debate. In vivo MRI/magnetic resonance spectroscopy studies have allowed insight into the development of brain edema in chronic HE. However, additional in vivo longitudinal and multiparametric/multimodal studies are required (in humans and animal models) to elucidate the relationship between liver function, brain metabolic changes, cellular changes, cell swelling, and neurological manifestations in chronic HE.
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Key Words
- 1H MRS, proton magnetic resonance spectroscopy
- ADC, apparent diffusion coefficient
- ALF, acute liver failure
- AQP, aquaporins
- BBB, blood-brain barrier
- BDL, bile duct ligation
- CNS, central nervous system
- CSF, cerebrospinal fluid
- Cr, creatine
- DTI, diffusion tensor imaging
- DWI, diffusion-weighted imaging
- FLAIR, fluid-attenuated inversion recovery
- GM, gray matter
- Gln, glutamine
- Glx, sum of glutamine and glutamate
- HE, hepatic encephalopathy
- Ins, inositol
- LPS, lipopolysaccharide
- Lac, lactate
- MD, mean diffusivity
- MRI, magnetic resonance imaging
- MRS, magnetic resonance spectroscopy
- MT, magnetization transfer
- MTR, MT ratio
- NMR, nuclear magnetic resonance
- PCA, portocaval anastomosis
- TE, echo time
- WM, white matter
- brain edema
- chronic hepatic encephalopathy
- in vivo magnetic resonance imaging
- in vivo magnetic resonance spectroscopy
- liver cirrhosis
- mIns, myo-inositol
- tCho, total choline
- tCr, total creatine
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Affiliation(s)
- Cristina Cudalbu
- Centre d'Imagerie Biomedicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Simon D. Taylor-Robinson
- Division of Integrative Systems Medicine and Digestive Disease, Department of Surgery and Cancer, St Mary's Hospital Campus, Imperial College London, London, United Kingdom
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27
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Zhu X, Nedelcovych MT, Thomas AG, Hasegawa Y, Moreno-Megui A, Coomer W, Vohra V, Saito A, Perez G, Wu Y, Alt J, Prchalova E, Tenora L, Majer P, Rais R, Rojas C, Slusher BS, Kamiya A. JHU-083 selectively blocks glutaminase activity in brain CD11b + cells and prevents depression-associated behaviors induced by chronic social defeat stress. Neuropsychopharmacology 2019; 44:683-694. [PMID: 30127344 PMCID: PMC6372721 DOI: 10.1038/s41386-018-0177-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 07/25/2018] [Accepted: 07/29/2018] [Indexed: 02/08/2023]
Abstract
There are a number of clinically effective treatments for stress-associated psychiatric diseases, including major depressive disorder (MDD). Nonetheless, many patients exhibit resistance to first-line interventions calling for novel interventions based on pathological mechanisms. Accumulating evidence implicates altered glutamate signaling in MDD pathophysiology, suggesting that modulation of glutamate signaling cascades may offer novel therapeutic potential. Here we report that JHU-083, our recently developed prodrug of the glutaminase inhibitor 6-diazo-5-oxo-L-norleucine (DON) ameliorates social avoidance and anhedonia-like behaviors in mice subjected to chronic social defeat stress (CSDS). JHU-083 normalized CSDS-induced increases in glutaminase activity specifically in microglia-enriched CD11b+ cells isolated from the prefrontal cortex and hippocampus. JHU-083 treatment also reverses the CSDS-induced inflammatory activation of CD11b+ cells. These results support the importance of altered glutamate signaling in the behavioral abnormalities observed in the CSDS model, and identify glutaminase in microglia-enriched CD11b+ cells as a pharmacotherapeutic target implicated in the pathophysiology of stress-associated psychiatric conditions such as MDD.
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Affiliation(s)
- Xiaolei Zhu
- 0000 0001 2171 9311grid.21107.35Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Michael T. Nedelcovych
- 0000 0001 2171 9311grid.21107.35Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD USA ,0000 0001 2171 9311grid.21107.35Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Ajit G. Thomas
- 0000 0001 2171 9311grid.21107.35Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Yuto Hasegawa
- 0000 0001 2171 9311grid.21107.35Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Aisa Moreno-Megui
- 0000 0001 2171 9311grid.21107.35Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Wade Coomer
- 0000 0001 2171 9311grid.21107.35Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Varun Vohra
- 0000 0001 2171 9311grid.21107.35Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Atsushi Saito
- 0000 0001 2171 9311grid.21107.35Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Gabriel Perez
- 0000 0001 2171 9311grid.21107.35Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Ying Wu
- 0000 0001 2171 9311grid.21107.35Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Jesse Alt
- 0000 0001 2171 9311grid.21107.35Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Eva Prchalova
- 0000 0001 2171 9311grid.21107.35Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD USA ,0000 0001 2171 9311grid.21107.35Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Lukáš Tenora
- 0000 0001 1015 3316grid.418095.1Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic v.v.i., Prague, Czech Republic
| | - Pavel Majer
- 0000 0001 1015 3316grid.418095.1Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic v.v.i., Prague, Czech Republic
| | - Rana Rais
- 0000 0001 2171 9311grid.21107.35Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD USA ,0000 0001 2171 9311grid.21107.35Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Camilo Rojas
- 0000 0001 2171 9311grid.21107.35Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD USA ,0000 0001 2171 9311grid.21107.35Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Barbara S. Slusher
- 0000 0001 2171 9311grid.21107.35Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD USA ,0000 0001 2171 9311grid.21107.35Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD USA ,0000 0001 2171 9311grid.21107.35Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD USA ,0000 0001 2171 9311grid.21107.35Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD USA ,0000 0001 2171 9311grid.21107.35Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD USA ,0000 0001 2171 9311grid.21107.35Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Atsushi Kamiya
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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28
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Heidari R. Brain mitochondria as potential therapeutic targets for managing hepatic encephalopathy. Life Sci 2019; 218:65-80. [DOI: 10.1016/j.lfs.2018.12.030] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 12/08/2018] [Accepted: 12/16/2018] [Indexed: 02/07/2023]
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29
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Wouters ATB, Wouters F, Boabaid FM, Watanabe TTN, Fredo G, Varaschin MS, Driemeier D. Brain lesions associated with acute toxic hepatopathy in cattle. J Vet Diagn Invest 2017; 29:287-292. [PMID: 28363257 DOI: 10.1177/1040638717699242] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Samples of the liver, telencephalon, brainstem, and cerebellum were obtained from 22 bovids suffering from spontaneous or experimental acute toxic liver disease. Perreyia flavipes larvae, and leaves of Cestrum corymbosum, Cestrum intermedium, Dodonaea viscosa, Trema micrantha, and Xanthium cavanillesii were the causal agents in the disorders studied. Hematoxylin and eosin and periodic acid-Schiff staining, as well as anti-S100 protein (anti-S100), anti-glial fibrillary acidic protein (anti-GFAP), and anti-vimentin immunostaining were used to evaluate the brain sections. Astrocytic changes were observed in all samples and were characterized by swollen vesicular nuclei in gray (Alzheimer type II astrocytes) and white matter; and by abundant eosinophilic or vacuolated cytoplasm with pyknotic nuclei in the white matter. These changes were evidenced by anti-S100 and anti-GFAP immunostaining. Our study demonstrates major changes in astrocytes of cattle that died with neurologic clinical signs as the result of acute toxic liver disease.
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Affiliation(s)
- Angelica T B Wouters
- Department of Veterinary Medicine, Federal University of Lavras, Lavras, Minas Gerais State, Brazil (A Wouters, F Wouters, Varaschin).,Faculty of Veterinary Medicine, Cuiabá University, Cuiabá, Mato Grosso, Brazil (Boabaid).,Department of Clinical Pathology, Faculty of Veterinary, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil (Fredo, Watanabe, Driemeier)
| | - Flademir Wouters
- Department of Veterinary Medicine, Federal University of Lavras, Lavras, Minas Gerais State, Brazil (A Wouters, F Wouters, Varaschin).,Faculty of Veterinary Medicine, Cuiabá University, Cuiabá, Mato Grosso, Brazil (Boabaid).,Department of Clinical Pathology, Faculty of Veterinary, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil (Fredo, Watanabe, Driemeier)
| | - Fabiana M Boabaid
- Department of Veterinary Medicine, Federal University of Lavras, Lavras, Minas Gerais State, Brazil (A Wouters, F Wouters, Varaschin).,Faculty of Veterinary Medicine, Cuiabá University, Cuiabá, Mato Grosso, Brazil (Boabaid).,Department of Clinical Pathology, Faculty of Veterinary, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil (Fredo, Watanabe, Driemeier)
| | - Tatiane T N Watanabe
- Department of Veterinary Medicine, Federal University of Lavras, Lavras, Minas Gerais State, Brazil (A Wouters, F Wouters, Varaschin).,Faculty of Veterinary Medicine, Cuiabá University, Cuiabá, Mato Grosso, Brazil (Boabaid).,Department of Clinical Pathology, Faculty of Veterinary, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil (Fredo, Watanabe, Driemeier)
| | - Gabriela Fredo
- Department of Veterinary Medicine, Federal University of Lavras, Lavras, Minas Gerais State, Brazil (A Wouters, F Wouters, Varaschin).,Faculty of Veterinary Medicine, Cuiabá University, Cuiabá, Mato Grosso, Brazil (Boabaid).,Department of Clinical Pathology, Faculty of Veterinary, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil (Fredo, Watanabe, Driemeier)
| | - Mary S Varaschin
- Department of Veterinary Medicine, Federal University of Lavras, Lavras, Minas Gerais State, Brazil (A Wouters, F Wouters, Varaschin).,Faculty of Veterinary Medicine, Cuiabá University, Cuiabá, Mato Grosso, Brazil (Boabaid).,Department of Clinical Pathology, Faculty of Veterinary, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil (Fredo, Watanabe, Driemeier)
| | - David Driemeier
- Department of Veterinary Medicine, Federal University of Lavras, Lavras, Minas Gerais State, Brazil (A Wouters, F Wouters, Varaschin).,Faculty of Veterinary Medicine, Cuiabá University, Cuiabá, Mato Grosso, Brazil (Boabaid).,Department of Clinical Pathology, Faculty of Veterinary, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil (Fredo, Watanabe, Driemeier)
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30
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Jang SY, Chang JY. Pathophysiology and Treatment of Cerebral Edema in Acute Liver Failure. JOURNAL OF NEUROCRITICAL CARE 2016. [DOI: 10.18700/jnc.160088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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31
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Lisser DFJ, Lister ZM, Pham-Ho PQH, Scott GR, Wilkie MP. Relationship between oxidative stress and brain swelling in goldfish (Carassius auratus) exposed to high environmental ammonia. Am J Physiol Regul Integr Comp Physiol 2016; 312:R114-R124. [PMID: 27784686 DOI: 10.1152/ajpregu.00208.2016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 10/20/2016] [Accepted: 10/21/2016] [Indexed: 12/14/2022]
Abstract
Buildups of ammonia can cause potentially fatal brain swelling in mammals, but such swelling is reversible in the anoxia- and ammonia-tolerant goldfish (Carassius auratus). We investigated brain swelling and its possible relationship to oxidative stress in the brain and liver of goldfish acutely exposed to high external ammonia (HEA; 5 mmol/l NH4Cl) at two different acclimation temperatures (14°C, 4°C). Exposure to HEA at 14°C for 72h resulted in increased internal ammonia and glutamine concentrations in the brain, and it caused cellular oxidative damage in the brain and liver. However, oxidative damage was most pronounced in brain, in which there was a twofold increase in thiobarbituric acid-reactive substances, a threefold increase in protein carbonylation, and a 20% increase in water volume (indicative of brain swelling). Increased activities of catalase, glutathione peroxidase, and glutathione reductase in the brain suggested that goldfish upregulate their antioxidant capacity to partially offset oxidative stress during hyperammonemia at 14°C. Notably, acclimation to colder (4°C) water completely attenuated the oxidative stress response to HEA in both tissues, and there was no change in brain water volume despite similar increases in internal ammonia. We suggest that ammonia-induced oxidative stress may be responsible for the swelling of goldfish brain during HEA, but further studies are needed to establish a mechanistic link between reactive oxygen species production and brain swelling. Nevertheless, a high capacity to withstand oxidative stress in response to variations in internal ammonia likely explains why goldfish are more resilient to this stressor than most other vertebrates.
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Affiliation(s)
- David F J Lisser
- Department of Biology and Laurier Institute for Water Science, Wilfrid Laurier University, Waterloo, Canada; and
| | - Zachary M Lister
- Department of Biology and Laurier Institute for Water Science, Wilfrid Laurier University, Waterloo, Canada; and
| | - Phillip Q H Pham-Ho
- Department of Biology and Laurier Institute for Water Science, Wilfrid Laurier University, Waterloo, Canada; and
| | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, Canada
| | - Michael P Wilkie
- Department of Biology and Laurier Institute for Water Science, Wilfrid Laurier University, Waterloo, Canada; and
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32
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Bartolić M, Vovk A, Šuput D. Effects of NH 4CL application and removal on astrocytes and endothelial cells. Cell Mol Biol Lett 2016; 21:13. [PMID: 28536616 PMCID: PMC5414667 DOI: 10.1186/s11658-016-0011-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 12/29/2015] [Indexed: 02/07/2023] Open
Abstract
Background Hepatic encephalopathy (HE) is a complex disorder associated with increased ammonia levels in the brain. Although astrocytes are believed to be the principal cells affected in hyperammonemia (HA), endothelial cells (ECs) may also play an important role by contributing to the vasogenic effect of HA. Methods Following acute application and removal of NH4Cl on astrocytes and endothelial cells, we analyzed pH changes, using fluorescence imaging with BCECF/AM, and changes in intracellular Ca2+ concentration ([Ca2+]i), employing fluorescence imaging with Fura-2/AM. Using confocal microscopy, changes in cell volume were observed accompanied by changes of [Ca2+]i in astrocytes and ECs. Results Exposure of astrocytes and ECs to 1 – 20 mM NH4Cl resulted in rapid concentration-dependent alkalinization of cytoplasm followed by slow recovery. Removal of the NH4Cl led to rapid concentration-dependent acidification, again followed by slow recovery. Following the application of NH4Cl, a transient, concentration-dependent rise in [Ca2+]i in astrocytes was observed. This was due to the release of Ca2+ from intracellular stores, since the response was abolished by emptying intracellular stores with thapsigargin and ATP, and was still present in the Ca2+-free bathing solution. The removal of NH4Cl also led to a transient concentration-dependent rise in [Ca2+]i that resulted from Ca2+ release from cytoplasmic proteins, since removing Ca2+ from the bathing solution and emptying intracellular Ca2+ stores did not eliminate the rise. Similar results were obtained from experiments on ECs. Following acute application and removal of NH4Cl no significant changes in astrocyte volume were detected; however, an increase of EC volume was observed after the administration of NH4Cl, and EC shrinkage was demonstrated after the acute removal of NH4Cl. Conclusions This study reveals new data which may give a more complete insight into the mechanism of development and treatment of HE.
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Affiliation(s)
- Miha Bartolić
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška cesta 4, 1000 Ljubljana, Slovenia
| | - Andrej Vovk
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška cesta 4, 1000 Ljubljana, Slovenia
| | - Dušan Šuput
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška cesta 4, 1000 Ljubljana, Slovenia
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Santos CL, Bobermin LD, Souza DG, Bellaver B, Bellaver G, Arús BA, Souza DO, Gonçalves CA, Quincozes-Santos A. Lipoic acid and N-acetylcysteine prevent ammonia-induced inflammatory response in C6 astroglial cells: The putative role of ERK and HO1 signaling pathways. Toxicol In Vitro 2015; 29:1350-7. [PMID: 26043815 DOI: 10.1016/j.tiv.2015.05.023] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 05/03/2015] [Accepted: 05/30/2015] [Indexed: 02/05/2023]
Abstract
Hyperammonemia induces significant changes in the central nervous system (CNS) in direct association with astroglial functions, such as oxidative damage, glutamatergic excitotoxicity, and impaired glutamine synthetase (GS) activity and pro-inflammatory cytokine release. Classically, lipoic acid (LA) and N-acetylcysteine (NAC) exhibit antioxidant and anti-inflammatory activities by increasing glutathione (GSH) biosynthesis and decreasing pro-inflammatory mediator levels in glial cells. Thus, we evaluated the protective effects of LA and NAC against ammonia cytotoxicity in C6 astroglial cells. Ammonia decreased GSH levels and increased cytokine release and NFκB transcriptional activation. LA and NAC prevented these effects by the modulation of ERK and HO1 pathways. Taken together, these observations show that LA and NAC prevent the ammonia-induced inflammatory response.
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Affiliation(s)
- Camila Leite Santos
- Departamento de Bioquímica, Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Larissa Daniele Bobermin
- Departamento de Bioquímica, Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Débora Guerini Souza
- Departamento de Bioquímica, Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Bruna Bellaver
- Departamento de Bioquímica, Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Gabriela Bellaver
- Departamento de Bioquímica, Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Bernardo Assein Arús
- Departamento de Bioquímica, Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Diogo Onofre Souza
- Departamento de Bioquímica, Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Carlos-Alberto Gonçalves
- Departamento de Bioquímica, Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - André Quincozes-Santos
- Departamento de Bioquímica, Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
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Pathogenesis of brain edema and investigation into anti-edema drugs. Int J Mol Sci 2015; 16:9949-75. [PMID: 25941935 PMCID: PMC4463627 DOI: 10.3390/ijms16059949] [Citation(s) in RCA: 194] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 04/15/2015] [Accepted: 04/27/2015] [Indexed: 12/18/2022] Open
Abstract
Brain edema is a potentially fatal pathological state that occurs after brain injuries such as stroke and head trauma. In the edematous brain, excess accumulation of extracellular fluid results in elevation of intracranial pressure, leading to impaired nerve function. Despite the seriousness of brain edema, only symptomatic treatments to remove edema fluid are currently available. Thus, the development of novel anti-edema drugs is required. The pathogenesis of brain edema is classified as vasogenic or cytotoxic edema. Vasogenic edema is defined as extracellular accumulation of fluid resulting from disruption of the blood-brain barrier (BBB) and extravasations of serum proteins, while cytotoxic edema is characterized by cell swelling caused by intracellular accumulation of fluid. Various experimental animal models are often used to investigate mechanisms underlying brain edema. Many soluble factors and functional molecules have been confirmed to induce BBB disruption or cell swelling and drugs targeted to these factors are expected to have anti-edema effects. In this review, we discuss the mechanisms and involvement of factors that induce brain edema formation, and the possibility of anti-edema drugs targeting them.
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Alt J, Potter MC, Rojas C, Slusher BS. Bioanalysis of 6-diazo-5-oxo-l-norleucine in plasma and brain by ultra-performance liquid chromatography mass spectrometry. Anal Biochem 2015; 474:28-34. [PMID: 25584882 DOI: 10.1016/j.ab.2015.01.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 12/30/2014] [Accepted: 01/02/2015] [Indexed: 11/16/2022]
Abstract
Glutamine is an abundant amino acid that plays pivotal roles in cell growth, cell metabolism, and neurotransmission. Dysregulation of glutamine-using pathways has been associated with pathological conditions such as cancer and neurodegenerative diseases. 6-Diazo-5-oxo-l-norleucine (DON) is a reactive glutamine analog that inhibits enzymes affecting glutamine metabolism such as glutaminase, 2-N-amidotransferase, l-asparaginase, and several enzymes involved in pyrimidine and purine de novo synthesis. As a result, DON is actively used in preclinical models of cancer and neurodegenerative disease. Moreover, there have been several clinical trials using DON to treat a variety of cancers. Considerations of dose and exposure are especially important with DON treatment due to its narrow therapeutic window and significant side effects. Consequently, a robust quantification bioassay is of interest. DON is a polar unstable molecule that has made quantification challenging. Here we report on the characterization of a bioanalytical method to quantify DON in tissue samples involving DON derivatization with 3 N HCl in butanol. The derivatized product is lipophilic and stable. Detection of this analyte by mass spectrometry is fast and specific and can be used to quantify DON in plasma and brain tissue with a limit of detection at the low nanomolar level.
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Affiliation(s)
- Jesse Alt
- Brain Science Institute, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Michelle C Potter
- Brain Science Institute, Johns Hopkins University, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Camilo Rojas
- Brain Science Institute, Johns Hopkins University, Baltimore, MD 21205, USA; Department of Molecular and Comparative Pathobiology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Barbara S Slusher
- Brain Science Institute, Johns Hopkins University, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA; Department of Psychiatry, Johns Hopkins University, Baltimore, MD 21205, USA; Department of Neuroscience, Johns Hopkins University, Baltimore, MD 21205, USA.
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Wilkie MP, Stecyk JAW, Couturier CS, Sidhu S, Sandvik GK, Nilsson GE. Reversible brain swelling in crucian carp (Carassius carassius) and goldfish (Carassius auratus) in response to high external ammonia and anoxia. Comp Biochem Physiol A Mol Integr Physiol 2015; 184:65-75. [PMID: 25582543 DOI: 10.1016/j.cbpa.2014.12.038] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 12/30/2014] [Accepted: 12/31/2014] [Indexed: 01/15/2023]
Abstract
Increased internal ammonia (hyperammonemia) and ischemic/anoxic insults are known to result in a cascade of deleterious events that can culminate in potentially fatal brain swelling in mammals. It is less clear, however, if the brains of fishes respond to ammonia in a similar manner. The present study demonstrated that the crucian carp (Carassius carassius) was not only able to endure high environmental ammonia exposure (HEA; 2 to 22 mmol L(-1)) but that they experienced 30% increases in brain water content at the highest ammonia concentrations. This swelling was accompanied by 4-fold increases in plasma total ammonia (TAmm) concentration, but both plasma TAmm and brain water content were restored to pre-exposure levels following depuration in ammonia-free water. The closely related, ammonia-tolerant goldfish (Carassius auratus) responded similarly to HEA (up to 3.6 mmol L(-1)), which was accompanied by 4-fold increases in brain glutamine. Subsequent administration of the glutamine synthetase inhibitor, methionine sulfoximine (MSO), reduced brain glutamine accumulation by 80% during HEA. However, MSO failed to prevent ammonia-induced increases in brain water content suggesting that glutamine may not be directly involved in initiating ammonia-induced brain swelling in fishes. Although the mechanisms of brain swelling are likely different, exposure to anoxia for 96 h caused similar, but lesser (10%) increases in brain water content in crucian carp. We conclude that brain swelling in some fishes may be a common response to increased internal ammonia or lower oxygen but further research is needed to deduce the underlying mechanisms behind such responses.
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Affiliation(s)
- Michael P Wilkie
- Department of Biology and Institute for Water Science, Wilfrid Laurier University, Waterloo, Ontario N2L 3C5, Canada; Department of Biosciences, University of Oslo, Oslo, Norway.
| | - Jonathan A W Stecyk
- Department of Biosciences, University of Oslo, Oslo, Norway; Department of Biological Sciences, University of Alaska Anchorage, Anchorage, USA
| | | | - Sanya Sidhu
- Department of Biology and Institute for Water Science, Wilfrid Laurier University, Waterloo, Ontario N2L 3C5, Canada
| | - Guro K Sandvik
- Department of Biosciences, University of Oslo, Oslo, Norway
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Jayakumar AR, Tong XY, Curtis KM, Ruiz-Cordero R, Shamaladevi N, Abuzamel M, Johnstone J, Gaidosh G, Rama Rao KV, Norenberg MD. Decreased astrocytic thrombospondin-1 secretion after chronic ammonia treatment reduces the level of synaptic proteins: in vitro and in vivo studies. J Neurochem 2014; 131:333-47. [PMID: 25040426 PMCID: PMC4364553 DOI: 10.1111/jnc.12810] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Revised: 06/16/2014] [Accepted: 06/22/2014] [Indexed: 12/23/2022]
Abstract
Chronic hepatic encephalopathy (CHE) is a major complication in patients with severe liver disease. Elevated blood and brain ammonia levels have been implicated in its pathogenesis, and astrocytes are the principal neural cells involved in this disorder. Since defective synthesis and release of astrocytic factors have been shown to impair synaptic integrity in other neurological conditions, we examined whether thrombospondin-1 (TSP-1), an astrocytic factor involved in the maintenance of synaptic integrity, is also altered in CHE. Cultured astrocytes were exposed to ammonia (NH₄Cl, 0.5-2.5 mM) for 1-10 days, and TSP-1 content was measured in cell extracts and culture media. Astrocytes exposed to ammonia exhibited a reduction in intra- and extracellular TSP-1 levels. Exposure of cultured neurons to conditioned media from ammonia-treated astrocytes showed a decrease in synaptophysin, PSD95, and synaptotagmin levels. Conditioned media from TSP-1 over-expressing astrocytes that were treated with ammonia, when added to cultured neurons, reversed the decline in synaptic proteins. Recombinant TSP-1 similarly reversed the decrease in synaptic proteins. Metformin, an agent known to increase TSP-1 synthesis in other cell types, also reversed the ammonia-induced TSP-1 reduction. Likewise, we found a significant decline in TSP-1 level in cortical astrocytes, as well as a reduction in synaptophysin content in vivo in a rat model of CHE. These findings suggest that TSP-1 may represent an important therapeutic target for CHE. Defective release of astrocytic factors may impair synaptic integrity in chronic hepatic encephalopathy. We found a reduction in the release of the astrocytic matricellular proteins thrombospondin-1 (TSP-1) in ammonia-treated astrocytes; such reduction was associated with a decrease in synaptic proteins caused by conditioned media from ammonia-treated astrocytes. Exposure of neurons to CM from ammonia-treated astrocytes, in which TSP-1 is over-expressed, reversed (by approx 75%) the reduction in synaptic proteins. NF-kB = nuclear factor kappa B; PSD95 = post-synaptic density protein 95; ONS = oxidative/nitrative stress.
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Affiliation(s)
- Arumugam R Jayakumar
- Laboratory of Neuropathology, Veterans Affairs Medical Center, Miami, Florida, USA
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Wang Q, Wang Y, Yu Z, Li D, Jia B, Li J, Guan K, Zhou Y, Chen Y, Kan Q. Ammonia-induced energy disorders interfere with bilirubin metabolism in hepatocytes. Arch Biochem Biophys 2014; 555-556:16-22. [PMID: 24878366 DOI: 10.1016/j.abb.2014.05.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 05/05/2014] [Accepted: 05/19/2014] [Indexed: 12/27/2022]
Abstract
Hyperammonemia and jaundice are the most common clinical symptoms of hepatic failure. Decreasing the level of ammonia in the blood is often accompanied by a reduction in bilirubin in patients with hepatic failure. Previous studies have shown that hyperammonemia can cause bilirubin metabolism disorders, however it is unclear exactly how hyperammonemia interferes with bilirubin metabolism in hepatocytes. The purpose of the current study was to determine the mechanism or mechanisms by which hyperammonemia interferes with bilirubin metabolism in hepatocytes. Cell viability and apoptosis were analyzed in primary hepatocytes that had been exposed to ammonium chloride. Mitochondrial morphology and permeability were observed and analyzed, intermediates of the tricarboxylic acid (TCA) cycle were determined and changes in the expression of enzymes related to bilirubin metabolism were analyzed after ammonia exposure. Hyperammonemia inhibited cell growth, induced apoptosis, damaged the mitochondria and hindered the TCA cycle in hepatocytes. This led to a reduction in energy synthesis, eventually affecting the expression of enzymes related to bilirubin metabolism, which then caused further problems with bilirubin metabolism. These effects were significant, but could be reversed with the addition of adenosine triphosphate (ATP). This study demonstrates that ammonia can cause problems with bilirubin metabolism by interfering with energy synthesis.
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Affiliation(s)
- Qiongye Wang
- Department of Pharmacology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yanfang Wang
- Department of Pharmacology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Zujiang Yu
- Department of Infectious Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Duolu Li
- Department of Pharmacology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Bin Jia
- Department of Pharmacology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Jingjing Li
- Department of Pharmacology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Kelei Guan
- Department of Pharmacology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yubing Zhou
- Department of Pharmacology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yanling Chen
- Department of Infectious Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Quancheng Kan
- Department of Pharmacology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.
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Chew SF, Ip YK. Excretory nitrogen metabolism and defence against ammonia toxicity in air-breathing fishes. JOURNAL OF FISH BIOLOGY 2014; 84:603-38. [PMID: 24438022 DOI: 10.1111/jfb.12279] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
With the development of air-breathing capabilities, some fishes can emerge from water, make excursions onto land or even burrow into mud during droughts. Air-breathing fishes have modified gill morphology and morphometry and accessory breathing organs, which would tend to reduce branchial ammonia excretion. As ammonia is toxic, air-breathing fishes, especially amphibious ones, are equipped with various strategies to ameliorate ammonia toxicity during emersion or ammonia exposure. These strategies can be categorized into (1) enhancement of ammonia excretion and reduction of ammonia entry, (2) conversion of ammonia to a less toxic product for accumulation and subsequent excretion, (3) reduction of ammonia production and avoidance of ammonia accumulation and (4) tolerance of ammonia at cellular and tissue levels. Active ammonia excretion, operating in conjunction with lowering of ambient pH and reduction in branchial and cutaneous NH₃ permeability, is theoretically the most effective strategy to maintain low internal ammonia concentrations. NH₃ volatilization involves the alkalization of certain epithelial surfaces and requires mechanisms to prevent NH₃ back flux. Urea synthesis is an energy-intensive process and hence uncommon among air-breathing teleosts. Aestivating African lungfishes detoxify ammonia to urea and the accumulated urea is excreted following arousal. Reduction in ammonia production is achieved in some air-breathing fishes through suppression of amino acid catabolism and proteolysis, or through partial amino acid catabolism leading to alanine formation. Others can slow down ammonia accumulation through increased glutamine synthesis in the liver and muscle. Yet, some others develop high tolerance of ammonia at cellular and tissue levels, including tissues in the brain. In summary, the responses of air-breathing fishes to ameliorate ammonia toxicity are many and varied, determined by the behaviour of the species and the nature of the environment in which it lives.
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Affiliation(s)
- S F Chew
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616, Republic of Singapore
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Scott TR, Kronsten VT, Hughes RD, Shawcross DL. Pathophysiology of cerebral oedema in acute liver failure. World J Gastroenterol 2013; 19:9240-9255. [PMID: 24409052 PMCID: PMC3882398 DOI: 10.3748/wjg.v19.i48.9240] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 10/28/2013] [Accepted: 11/19/2013] [Indexed: 02/06/2023] Open
Abstract
Cerebral oedema is a devastating consequence of acute liver failure (ALF) and may be associated with the development of intracranial hypertension and death. In ALF, some patients may develop cerebral oedema and increased intracranial pressure but progression to life-threatening intracranial hypertension is less frequent than previously described, complicating less than one third of cases who have proceeded to coma since the advent of improved clinical care. The rapid onset of encephalopathy may be dramatic with the development of asterixis, delirium, seizures and coma. Cytotoxic and vasogenic oedema mechanisms have been implicated with a preponderance of experimental data favouring a cytotoxic mechanism. Astrocyte swelling is the most consistent neuropathological finding in humans with ALF and ammonia plays a definitive role in the development of cytotoxic brain oedema. The mechanism(s) by which ammonia induces astrocyte swelling remains unclear but glutamine accumulation within astrocytes has led to the osmolyte hypothesis. Current evidence also supports an alternate ‘Trojan horse’ hypothesis, with glutamine as a carrier of ammonia into mitochondria, where its accumulation results in oxidative stress, energy failure and ultimately astrocyte swelling. Although a complete breakdown of the blood-brain barrier is not evident in human ALF, increased permeation to water and other small molecules such as ammonia has been demonstrated resulting from subtle alterations in the protein composition of paracellular tight junctions. At present, there is no fully efficacious therapy for cerebral oedema other than liver transplantation and this reflects our incomplete knowledge of the precise mechanisms underlying this process which remain largely unknown.
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Bjerring PN, Larsen FS. Changes in cerebral oxidative metabolism in patients with acute liver failure. Metab Brain Dis 2013; 28:179-82. [PMID: 23099996 DOI: 10.1007/s11011-012-9346-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2012] [Accepted: 10/15/2012] [Indexed: 10/27/2022]
Abstract
Acute liver failure patients with a persistence of hyperammonemia are at an increased risk of intracranial hypertension due to development of brain oedema. In vitro studies of brain tissue and cell cultures that indicates that exposure to ammonium inhibits enzymatic activity in the tricarboxylic acid cycle, induces substrate depletion through marked glutamate utilization for glutamine synthesis and leads to mitochondrial dysfunction. In patients with acute liver failure cerebral microdialysis studies show a linear correlation between the lactate to pyruvate ratio and the glutamine concentration, as well as to some of the adenosine triphosphate degradation products. However, clinical observations of cerebral exchange rates of oxygen, glucose, lactate and amino acids challenge the interpretation of these findings. In this review the conflicting data of cerebral metabolism during acute liver failure is discussed.
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Affiliation(s)
- P N Bjerring
- Department of Hepatology, Rigshospitalet, Copenhagen, Denmark.
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Obara-Michlewska M, Tuszyńska P, Albrecht J. Ammonia upregulates kynurenine aminotransferase II mRNA expression in rat brain: a role for astrocytic NMDA receptors? Metab Brain Dis 2013; 28:161-5. [PMID: 23132651 DOI: 10.1007/s11011-012-9353-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 10/24/2012] [Indexed: 11/25/2022]
Abstract
Kynurenine aminotransferase II (KAT-II) is the astrocytic enzyme catalyzing the synthesis of kynurenic acid (KYNA), an endogenous inhibitor of the α7-nicotinic receptor and the NMDA receptor (NMDAr). A previous study demonstrated an increase of KYNA synthesis in the brain of rats with thioacetamide (TAA)-induced acute liver failure. Here we show that TAA administration increases KAT-II expression in the rat cerebral cortex and the effect is mimicked in cerebral cortical astrocytes in culture treated with high (5 mM) concentration of ammonia. KAT-II expression in control and TAA-treated rats was increased by NMDAr antagonist memantine, and the effects of TAA and memantine appeared additive. In astrocytes, the NMDAr antagonist MK-801 raised KAT-II expression as well, while NMDA added alone had no effect. Glutamate decreased KAT-II mRNA level, which was attenuated by MK-801. The results suggest that stimulation of KAT-II expression during hepatic encephalopathy may be associated with a partial inactivation of astrocytic NMDAr by ammonia.
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Affiliation(s)
- Marta Obara-Michlewska
- Department of Neurotoxicology, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland.
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Rama Rao KV, Norenberg MD. Glutamine in the pathogenesis of hepatic encephalopathy: the trojan horse hypothesis revisited. Neurochem Res 2013; 39:593-8. [PMID: 23277414 DOI: 10.1007/s11064-012-0955-2] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 12/19/2012] [Indexed: 01/16/2023]
Abstract
Hepatic encephalopathy (HE) is major neuropsychiatric disorder occurring in patients with severe liver disease and ammonia is generally considered to represent the major toxin responsible for this condition. Ammonia in brain is chiefly metabolized ("detoxified") to glutamine in astrocytes due to predominant localization of glutamine synthetase in these cells. While glutamine has long been considered innocuous, a deleterious role more recently has been attributed to this amino acid. This article reviews the mechanisms by which glutamine contributes to the pathogenesis of HE, how glutamine is transported into mitochondria and subsequently hydrolyzed leading to high levels of ammonia, the latter triggering oxidative and nitrative stress, the mitochondrial permeability transition and mitochondrial injury, a sequence of events we have collectively termed as the Trojan horse hypothesis of hepatic encephalopathy.
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Affiliation(s)
- Kakulavarapu V Rama Rao
- Department of Pathology, University of Miami Miller School of Medicine, P.O. BOX 016960, Miami, FL, 33101, USA
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Bobermin LD, Quincozes-Santos A, Guerra MC, Leite MC, Souza DO, Gonçalves CA, Gottfried C. Resveratrol prevents ammonia toxicity in astroglial cells. PLoS One 2012; 7:e52164. [PMID: 23284918 PMCID: PMC3528750 DOI: 10.1371/journal.pone.0052164] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 11/15/2012] [Indexed: 02/07/2023] Open
Abstract
Ammonia is implicated as a neurotoxin in brain metabolic disorders associated with hyperammonemia. Acute ammonia toxicity can be mediated by an excitotoxic mechanism, oxidative stress and nitric oxide (NO) production. Astrocytes interact with neurons, providing metabolic support and protecting against oxidative stress and excitotoxicity. Astrocytes also convert excess ammonia and glutamate into glutamine via glutamine synthetase (GS). Resveratrol, a polyphenol found in grapes and red wines, exhibits antioxidant and anti-inflammatory properties and modulates glial functions, such as glutamate metabolism. We investigated the effect of resveratrol on the production of reactive oxygen species (ROS), GS activity, S100B secretion, TNF-α, IL-1β and IL-6 levels in astroglial cells exposed to ammonia. Ammonia induced oxidative stress, decreased GS activity and increased cytokines release, probably by a mechanism dependent on protein kinase A (PKA) and extracellular signal-regulated kinase (ERK) pathways. Resveratrol prevented ammonia toxicity by modulating oxidative stress, glial and inflammatory responses. The ERK and nuclear factor-κB (NF-κB) are involved in the protective effect of resveratrol on cytokines proinflammatory release. In contrast, other antioxidants (e.g., ascorbic acid and trolox) were not effective against hyperammonemia. Thus, resveratrol could be used to protect against ammonia-induced neurotoxicity.
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Affiliation(s)
- Larissa Daniele Bobermin
- Department of Biochemistry, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - André Quincozes-Santos
- Department of Biochemistry, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
- * E-mail:
| | - Maria Cristina Guerra
- Department of Biochemistry, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Marina Concli Leite
- Department of Biochemistry, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Diogo Onofre Souza
- Department of Biochemistry, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Carlos-Alberto Gonçalves
- Department of Biochemistry, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Carmem Gottfried
- Department of Biochemistry, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
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Bodega G, Suárez I, López-Fernández LA, García MI, Köber M, Penedo M, Luna M, Juárez S, Ciordia S, Oria M, Córdoba J, Fernández B. Ammonia induces aquaporin-4 rearrangement in the plasma membrane of cultured astrocytes. Neurochem Int 2012; 61:1314-24. [PMID: 23022607 DOI: 10.1016/j.neuint.2012.09.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 09/06/2012] [Accepted: 09/13/2012] [Indexed: 11/30/2022]
Abstract
Aquaporin-4 (AQP4) is a water channel protein mainly located in the astroglial plasma membrane, the precise function of which in the brain edema that accompanies hepatic encephalopathy (HE) is unclear. Since ammonia is the main pathogenic agent in HE, its effect on AQP4 expression and distribution in confluent primary astroglial cultures was examined via their exposure to ammonium chloride (1, 3 and 5 mM) for 5 and 10 days. Ammonia induced the general inhibition of AQP4 mRNA synthesis except in the 1 mM/5 day treatment. However, the AQP4 protein content measured was dependent on the method of analysis; an apparent increase was recorded in treated cells in in-cell Western assays, while an apparent reduction was seen with the classic Western blot method, perhaps due to differences in AQP4 aggregation. Ammonia might therefore induce the formation of insoluble AQP4 aggregates in the astroglial plasma membrane. The finding of AQP4 in the pellet of classic Western blot samples, plus data obtained via confocal microscopy, atomic force microscopy (using immunolabeled cells with gold nanoparticles) and scanning electron microscopy, all corroborate this hypothesis. The effect of ammonia on AQP4 seems not to be due to any osmotic effect; identical osmotic stress induced by glutamine and salt had no significant effect on the AQP4 content. AQP4 functional analysis (subjecting astrocytes to a hypo-osmotic medium and using flow cytometry to measure cell size) demonstrated a smaller water influx in ammonia-treated astrocytes suggesting that AQP4 aggregates are representative of an inactive status; however, more confirmatory studies are required to fully understand the functional status of AQP4 aggregates. The present results suggest that ammonia affects AQP4 expression and distribution, and that astrocytes change their expression of AQP4 mRNA as well as the aggregation status of the ensuing protein depending on the ammonia concentration and duration of exposure.
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Affiliation(s)
- Guillermo Bodega
- Departamento de Biología Celular y Genética, Facultad de Biología, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain.
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Kaufmann W, Bolon B, Bradley A, Butt M, Czasch S, Garman RH, George C, Gröters S, Krinke G, Little P, McKay J, Narama I, Rao D, Shibutani M, Sills R. Proliferative and nonproliferative lesions of the rat and mouse central and peripheral nervous systems. Toxicol Pathol 2012; 40:87S-157S. [PMID: 22637737 DOI: 10.1177/0192623312439125] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Harmonization of diagnostic nomenclature used in the pathology analysis of tissues from rodent toxicity studies will enhance the comparability and consistency of data sets from different laboratories worldwide. The INHAND Project (International Harmonization of Nomenclature and Diagnostic Criteria for Lesions in Rats and Mice) is a joint initiative of four major societies of toxicologic pathology to develop a globally recognized nomenclature for proliferative and nonproliferative lesions in rodents. This article recommends standardized terms for classifying changes observed in tissues of the mouse and rat central (CNS) and peripheral (PNS) nervous systems. Sources of material include academic, government, and industrial histopathology databases from around the world. Covered lesions include frequent, spontaneous, and aging-related changes as well as principal toxicant-induced findings. Common artifacts that might be confused with genuine lesions are also illustrated. The neural nomenclature presented in this document is also available electronically on the Internet at the goRENI website (http://www.goreni.org/).
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48
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Glutamine in the pathogenesis of acute hepatic encephalopathy. Neurochem Int 2012; 61:575-80. [DOI: 10.1016/j.neuint.2012.01.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 01/11/2012] [Accepted: 01/12/2012] [Indexed: 01/28/2023]
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Manganese and ammonia interactions in the brain of cirrhotic rats: effects on brain ammonia metabolism. Neurochem Res 2012; 37:1074-84. [PMID: 22290316 DOI: 10.1007/s11064-012-0710-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Revised: 01/13/2012] [Accepted: 01/18/2012] [Indexed: 01/18/2023]
Abstract
Hepatic encephalopathy is a major complication of cirrhosis. Ammonia and manganese have been associated with hepatic encephalopathy underlying mechanisms. Motor impairment and brain edema are common signs of hepatic encephalopathy. In the present study a model of liver damage in rats was combined with ammonia and manganese exposure to evaluate the role of these substances separately and their interactions on brain glutamine, water content and motor coordination. Additionally, we explored brain levels of each substance -Mn and ammonia- in the presence or absence of the other. Liver damage was induced by bile duct ligation. Rats were exposed to MnCl2 in drinking water (1 mg Mn/ml) and to ammonia in chow pellets containing 20% ammonium acetate (w/w). As expected, manganese and ammonia levels increased in the brain of cirrhotic rats exposed to these substances; in these animals, glutamine brain levels also increased and positively correlated with tissue water content in cortex. A three way-ANOVA showed that manganese favored ammonia and glutamine accumulation in brain, and possibly their subsequent deleterious effects, as evidenced by the fact that manganese and ammonia accumulation in the brain of cirrhotic rats severely affected motor function. These results suggest that even when controlling ammonia levels in cirrhotic patients, reduction of manganese intake is also a potential strategy to be considered in clinical practice.
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Schwarz CS, Ferrea S, Quasthoff K, Walter J, Görg B, Häussinger D, Schnitzler A, Hartung HP, Dihné M. Ammonium chloride influences in vitro-neuronal network activity. Exp Neurol 2012; 235:368-73. [DOI: 10.1016/j.expneurol.2012.02.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Revised: 02/27/2012] [Accepted: 02/29/2012] [Indexed: 11/16/2022]
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