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Niknahad H, Mobasheri A, Arjmand A, Rafiei E, Alidaee S, Razavi H, Bagheri S, Rezaei H, Sabouri S, Najibi A, Khodaei F, Kashani SMA, Ommati MM, Heidari R. Hepatic encephalopathy complications are diminished by piracetam via the interaction between mitochondrial function, oxidative stress, inflammatory response, and locomotor activity. Heliyon 2023; 9:e20557. [PMID: 37810869 PMCID: PMC10551565 DOI: 10.1016/j.heliyon.2023.e20557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 09/01/2023] [Accepted: 09/28/2023] [Indexed: 10/10/2023] Open
Abstract
Background of the study: Hepatic encephalopathy (HE) is a complication in which brain ammonia (NH4+) levels reach critically high concentrations because of liver failure. HE could lead to a range of neurological complications from locomotor and behavioral disturbances to coma. Several tactics have been established for subsiding blood and brain NH4+. However, there is no precise intervention to mitigate the direct neurological complications of NH4+. Purpose It has been found that oxidative stress, mitochondrial damage, and neuro-inflammation play a fundamental role in NH4+ neurotoxicity. Piracetam is a drug used clinically in neurological complications such as stroke and head trauma. Piracetam could significantly diminish oxidative stress and improve brain mitochondrial function. Research methods In the current study, piracetam (100 and 500 mg/kg, oral) was used in a mice model of HE induced by thioacetamide (TA, 800 mg/kg, single dose, i.p). Results Significant disturbances in animals' locomotor activity, along with increased oxidative stress biomarkers, including reactive oxygen species formation, protein carbonylation, lipid peroxidation, depleted tissue glutathione, and decreased antioxidant capacity, were evident in the brain of TA-treated mice. Meanwhile, mitochondrial permeabilization, mitochondrial depolarization, suppression of dehydrogenases activity, and decreased ATP levels were found in the brain of the TA group. The level of pro-inflammatory cytokines was also significantly high in the brain of HE animals. Conclusion It was found that piracetam significantly enhanced mice's locomotor activity, blunted oxidative stress biomarkers, decreased inflammatory cytokines, and improved mitochondrial indices in hyperammonemic mice. These data suggest piracetam as a neuroprotective agent which could be repurposed for the management of HE.
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Affiliation(s)
- Hossein Niknahad
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Pharmacology and Toxicology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Ali Mobasheri
- Research Unit of Medical Imaging, Physics, And Technology, Faculty of Medicine, University of Oulu, FI-90014, Oulu, Finland
- University Medical Center Utrecht, Departments of Orthopedics Rheumatology and Clinical Immunology, 3508, GA, Utrecht, the Netherlands
- Department of Regenerative Medicine, State Research Institute Centre for Innovative Medicine, LT-08406, Vilnius, Lithuania
| | - Abdollah Arjmand
- Department of Toxicology and Pharmacology, Faculty of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Elahe Rafiei
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Sepideh Alidaee
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Hadi Razavi
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Pharmacology and Toxicology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Sara Bagheri
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Heresh Rezaei
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Pharmacology and Toxicology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Samira Sabouri
- Shanxi Key Laboratory of Ecological, Animal Sciences, And Environmental Veterinary Medicine, College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi, 030801, China
| | - Asma Najibi
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Pharmacology and Toxicology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Forouzan Khodaei
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Seyyed Mohammad Amin Kashani
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Pharmacology and Toxicology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammad Mehdi Ommati
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Shanxi Key Laboratory of Ecological, Animal Sciences, And Environmental Veterinary Medicine, College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi, 030801, China
- Henan Key Laboratory of Environmental and Animal Product Safety, College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471000, Henan, China
| | - Reza Heidari
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
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Angelova PR, Kerbert AJ, Habtesion A, Hall A, Abramov AY, Jalan R. Hyperammonemia induces mitochondrial dysfunction and neuronal cell death. JHEP REPORTS : INNOVATION IN HEPATOLOGY 2022; 4:100510. [PMID: 35845295 PMCID: PMC9278080 DOI: 10.1016/j.jhepr.2022.100510] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 04/21/2022] [Accepted: 05/10/2022] [Indexed: 11/27/2022]
Abstract
Background & Aims In cirrhosis, astrocytic swelling is believed to be the principal mechanism of ammonia neurotoxicity leading to hepatic encephalopathy (HE). The role of neuronal dysfunction in HE is not clear. We aimed to explore the impact of hyperammonaemia on mitochondrial function in primary co-cultures of neurons and astrocytes and in acute brain slices of cirrhotic rats using live cell imaging. Methods To primary cocultures of astrocytes and neurons, low concentrations (1 and 5 μM) of NH4Cl were applied. In rats with bile duct ligation (BDL)-induced cirrhosis, a model known to induce hyperammonaemia and minimal HE, acute brain slices were studied. One group of BDL rats was treated twice daily with the ammonia scavenger ornithine phenylacetate (OP; 0.3 g/kg). Fluorescence measurements of changes in mitochondrial membrane potential (Δψm), cytosolic and mitochondrial reactive oxygen species (ROS) production, lipid peroxidation (LP) rates, and cell viability were performed using confocal microscopy. Results Neuronal cultures treated with NH4Cl exhibited mitochondrial dysfunction, ROS overproduction, and reduced cell viability (27.8 ± 2.3% and 41.5 ± 3.7%, respectively) compared with untreated cultures (15.7 ± 1.0%, both p <0.0001). BDL led to increased cerebral LP (p = 0.0003) and cytosolic ROS generation (p <0.0001), which was restored by OP (both p <0.0001). Mitochondrial function was severely compromised in BDL, resulting in hyperpolarisation of Δψm with consequent overconsumption of adenosine triphosphate and augmentation of mitochondrial ROS production. Administration of OP restored Δψm. In BDL animals, neuronal loss was observed in hippocampal areas, which was partially prevented by OP. Conclusions Our results elucidate that low-grade hyperammonaemia in cirrhosis can severely impact on brain mitochondrial function. Profound neuronal injury was observed in hyperammonaemic conditions, which was partially reversible by OP. This points towards a novel mechanism of HE development. Lay summary The impact of hyperammonaemia, a common finding in patients with liver cirrhosis, on brain mitochondrial function was investigated in this study. The results show that ammonia in concentrations commonly seen in patients induces severe mitochondrial dysfunction, overproduction of damaging oxygen molecules, and profound injury and death of neurons in rat brain cells. These findings point towards a novel mechanism of ammonia-induced brain injury in liver failure and potential novel therapeutic targets. Low concentrations of ammonia induce mitochondrial dysfunction, overproduction of ROS, and cell death in primary neurons. Hyperammonaemia in cirrhotic rats leads to ROS and LP overproduction, which was prevented by the ammonia scavenger OP. In neurons from cirrhotic rats, hyperpolarisation of Δψm was observed, which was restored by OP treatment. In a rat model of cirrhosis, profound neuronal loss was observed in the hippocampus.
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Pierzchala K, Simicic D, Sienkiewicz A, Sessa D, Mitrea S, Braissant O, McLin VA, Gruetter R, Cudalbu C. Central nervous system and systemic oxidative stress interplay with inflammation in a bile duct ligation rat model of type C hepatic encephalopathy. Free Radic Biol Med 2022; 178:295-307. [PMID: 34890769 DOI: 10.1016/j.freeradbiomed.2021.12.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/12/2021] [Accepted: 12/06/2021] [Indexed: 02/07/2023]
Abstract
The role and coexistence of oxidative stress (OS) and inflammation in type C hepatic encephalopathy (C HE) is a subject of intense debate. Under normal conditions the physiological levels of intracellular reactive oxygen species are controlled by the counteracting antioxidant response to maintain redox homeostasis. Our previous in-vivo1H-MRS studies revealed the longitudinal impairment of the antioxidant system (ascorbate) in a bile-duct ligation (BDL) rat model of type C HE. Therefore, the aim of this work was to examine the course of central nervous system (CNS) OS and systemic OS, as well as to check for their co-existence with inflammation in the BDL rat model of type C HE. To this end, we implemented a multidisciplinary approach, including ex-vivo and in-vitro electron paramagnetic resonance spectroscopy (EPR) spin-trapping, which was combined with UV-Vis spectroscopy, and histological assessments. We hypothesized that OS and inflammation act synergistically in the pathophysiology of type C HE. Our findings point to an increased CNS- and systemic-OS and inflammation over the course of type C HE progression. In particular, an increase in the CNS OS was observed as early as 2-weeks post-BDL, while the systemic OS became significant at week 6 post-BDL. The CNS EPR measurements were further validated by a substantial accumulation of 8-Oxo-2'-deoxyguanosine (Oxo-8-dG), a marker of oxidative DNA/RNA modifications on immunohistochemistry (IHC). Using IHC, we also detected increased synthesis of antioxidants, glutathione peroxidase 1 (GPX-1) and superoxide dismutases (i.e.Cu/ZnSOD (SOD1) and MnSOD (SOD2)), along with proinflammatory cytokine interleukin-6 (IL-6) in the brains of BDL rats. The presence of systemic inflammation was observed already at 2-weeks post-surgery. Thus, these results suggest that CNS OS is an early event in type C HE rat model, which seems to precede systemic OS. Finally, our results suggest that the increase in CNS OS is due to enhanced formation of intra- and extra-cellular ROS rather than due to reduced antioxidant capacity, and that OS in parallel with inflammation plays a significant role in type C HE.
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Affiliation(s)
- K Pierzchala
- Center for Biomedical Imaging, EPFL, Lausanne, Switzerland; Animal Imaging and Technology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; Laboratory of Functional and Metabolic Imaging, EPFL, Lausanne, Switzerland.
| | - D Simicic
- Center for Biomedical Imaging, EPFL, Lausanne, Switzerland; Animal Imaging and Technology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; Laboratory of Functional and Metabolic Imaging, EPFL, Lausanne, Switzerland
| | - A Sienkiewicz
- Laboratory for Quantum Magnetism, Institute of Physics, EPFL, Lausanne, Switzerland; ADSresonances Sàrl, Préverenges, Switzerland
| | - D Sessa
- Swiss Pediatric Liver Center, Department of Pediatrics, Gynecology and Obstetrics, University Hospitals Geneva and University of Geneva, Geneva, Switzerland
| | - S Mitrea
- Center for Biomedical Imaging, EPFL, Lausanne, Switzerland; Animal Imaging and Technology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - O Braissant
- Service of Clinical Chemistry, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - V A McLin
- Swiss Pediatric Liver Center, Department of Pediatrics, Gynecology and Obstetrics, University Hospitals Geneva and University of Geneva, Geneva, Switzerland
| | - R Gruetter
- Center for Biomedical Imaging, EPFL, Lausanne, Switzerland; Laboratory of Functional and Metabolic Imaging, EPFL, Lausanne, Switzerland
| | - C Cudalbu
- Center for Biomedical Imaging, EPFL, Lausanne, Switzerland; Animal Imaging and Technology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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Dąbrowska K, Skowrońska K, Popek M, Albrecht J, Zielińska M. The Role of Nrf2 Transcription Factor and Sp1-Nrf2 Protein Complex in Glutamine Transporter SN1 Regulation in Mouse Cortical Astrocytes Exposed to Ammonia. Int J Mol Sci 2021; 22:ijms222011233. [PMID: 34681893 PMCID: PMC8538223 DOI: 10.3390/ijms222011233] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/14/2021] [Accepted: 10/15/2021] [Indexed: 11/28/2022] Open
Abstract
Ammonia toxicity in the brain primarily affects astrocytes via a mechanism in which oxidative stress (OS), is coupled to the imbalance between glutamatergic and GABAergic transmission. Ammonia also downregulates the astrocytic N system transporter SN1 that controls glutamine supply from astrocytes to neurons for the replenishment of both neurotransmitters. Here, we tested the hypothesis that activation of Nrf2 is the process that links ammonia-induced OS formation in astrocytes to downregulation and inactivation of SN1 and that it may involve the formation of a complex between Nrf2 and Sp1. Treatment of cultured cortical mouse astrocytes with ammonia (5 mM NH4Cl for 24 h) evoked Nrf2 nuclear translocation, increased its activity in a p38 MAPK pathway-dependent manner, and enhanced Nrf2 binding to Slc38a3 promoter. Nrf2 silencing increased SN1 mRNA and protein level without influencing astrocytic [3H]glutamine transport. Ammonia decreased SN1 expression in Nrf2 siRNA treated astrocytes and reduced [3H]glutamine uptake. In addition, while Nrf2 formed a complex with Sp1 in ammonia-treated astrocytes less efficiently than in control cells, treatment of astrocytes with hybrid-mode inactivated Sp1-Nrf2 complex (Nrf2 silencing + pharmacological inhibition of Sp1) did not affect SN1 protein level in ammonia-treated astrocytes. In summary, the results document that SN1 transporter dysregulation by ammonia in astrocytes involves activation of Nrf2 but does not require the formation of the Sp1-Nrf2 complex.
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Altered motor cortical plasticity in patients with hepatic encephalopathy: A paired associative stimulation study. Clin Neurophysiol 2021; 132:2332-2341. [PMID: 34454259 DOI: 10.1016/j.clinph.2021.07.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 06/29/2021] [Accepted: 07/03/2021] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Hepatic encephalopathy (HE) is a potentially reversible brain dysfunction caused by liver failure. Altered synaptic plasticity is supposed to play a major role in the pathophysiology of HE. Here, we used paired associative stimulation with an inter-stimulus interval of 25 ms (PAS25), a transcranial magnetic stimulation (TMS) protocol, to test synaptic plasticity of the motor cortex in patients with manifest HE. METHODS 23 HE-patients and 23 healthy controls were enrolled in the study. Motor evoked potential (MEP) amplitudes were assessed as measure for cortical excitability. Time courses of MEP amplitude changes after the PAS25 intervention were compared between both groups. RESULTS MEP-amplitudes increased after PAS25 in the control group, indicating PAS25-induced synaptic plasticity in healthy controls, as expected. In contrast, MEP-amplitudes within the HE group did not change and were lower than in the control group, indicating no induction of plasticity. CONCLUSIONS Our study revealed reduced synaptic plasticity of the primary motor cortex in HE. SIGNIFICANCE Reduced synaptic plasticity in HE provides a link between pathological changes on the molecular level and early clinical symptoms of the disease. This decrease may be caused by disturbances in the glutamatergic neurotransmission due to the known hyperammonemia in HE patients.
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Hajipour S, Farbood Y, Dianat M, Rashno M, Khorsandi LS, Sarkaki A. Thymoquinone improves behavioral and biochemical deficits in hepatic encephalopathy induced by thioacetamide in rats. Neurosci Lett 2021; 745:135617. [PMID: 33421492 DOI: 10.1016/j.neulet.2020.135617] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 12/22/2020] [Accepted: 12/28/2020] [Indexed: 02/06/2023]
Abstract
Hepatic encephalopathy (HE) is a cerebral function alteration in patients with liver dysfunction. The present study aimed to evaluate the therapeutic effects of thymoquinone (TQ) on behavioral deficits and its possible mechanism(s) in a thioacetamide (TAA)-induced HE model. HE was induced in male Wistar rats by intraperitoneal (i.p.) injection of TAA (200 mg/kg) for once every 48 h for 14 consecutive days. Thymoquinone (5, 10, and 20 mg/kg) was administered for seven consecutive days (i.p.) after HE induction. Anxiety and depression-like behaviors assessed by standard paradigms respectively. Finally, their brain hippocampus sections prepared to evaluate the oxidative stress changes in rats. Data showed treatment HE rats with TQ ameliorated anxiety and depression-like behaviors. TQ administration also reduced oxidative stress due to its potential to enhance the levels of glutathione-peroxidase (GPx), catalase (CAT), and total thiol content in the hippocampus. These findings suggest that TQ has notable effects against acute hepatic failure and HE complications through modulation of oxidative stress.
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Affiliation(s)
- Somayeh Hajipour
- Persian Gulf Physiology Research Center. Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Yaghoob Farbood
- Persian Gulf Physiology Research Center. Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran; Department of Physiology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Mahin Dianat
- Persian Gulf Physiology Research Center. Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran; Department of Physiology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Mohammad Rashno
- Department of Immunology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Laya Sadat Khorsandi
- Department of Anatomical Sciences, Cellular & Molecular Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Alireza Sarkaki
- Persian Gulf Physiology Research Center. Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran; Department of Physiology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran; Medicinal Plant Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz. Iran.
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Mohammadi H, Sayad A, Mohammadi M, Niknahad H, Heidari R. N-acetyl cysteine treatment preserves mitochondrial indices of functionality in the brain of hyperammonemic mice. Clin Exp Hepatol 2020; 6:106-115. [PMID: 32728627 PMCID: PMC7380475 DOI: 10.5114/ceh.2020.95814] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 02/20/2020] [Indexed: 12/11/2022] Open
Abstract
AIM OF THE STUDY Acute or chronic live failure could result in hyperammonemia and hepatic encephalopathy (HE). HE is a clinical complication characterized by severe cognitive dysfunction and coma. The ammonium ion (NH4 +) is the most suspected toxic molecule involved in the pathogenesis of HE. NH4 + is a neurotoxic agent. Different mechanisms, including oxidative/nitrosative stress, inflammatory response, excitotoxicity, and mitochondrial impairment, are proposed for NH4 +-induced neurotoxicity. N-acetyl cysteine (NAC) is a well-known thiol-reductant and antioxidant agent. Several investigations also mentioned the positive effects of NAC on mitochondrial function. In the current study, the effect of NAC treatment on brain mitochondrial indices and energy status was investigated in an animal model of HE. MATERIAL AND METHODS Acetaminophen (APAP)-induced acute liver failure was induced by a single dose of the drug (800 mg/kg, i.p.) to C57BL/6J mice. Plasma and brain levels of NH4 + were measured. Then, brain mitochondria were isolated, and several indices, including mitochondrial depolarization, ATP level, lipid peroxidation, glutathione content, mitochondrial permeabilization, and dehydrogenase activity, were assessed. RESULTS A significant increase in plasma and brain NH4 + was evident in APAP-treated animals. Moreover, mitochondrial indices of functionality were impaired, and mitochondrial oxidative stress biomarkers were significantly increased in APAP-treated mice. It was found that NAC treatment (100, 200, and 400 mg/kg, i.p.) significantly mitigated mitochondrial impairment in the brain of APAP-treated animals. CONCLUSIONS These data suggest the effects of NAC on brain mitochondrial function and energy status as a pivotal mechanism involved in its neuroprotective properties during HE.
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Affiliation(s)
- Hamidreza Mohammadi
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Pharmacology and Toxicology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Abolfazl Sayad
- Department of Pharmacology and Toxicology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohsen Mohammadi
- Hepatitis Research Center, Lorestan University of Medical Sciences, Khorramabad, Iran
| | - Hossein Niknahad
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Pharmacology and Toxicology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Reza Heidari
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
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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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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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Abstract
During water-land transition, ancient fishes acquired the ability to breathe air, but air-breathing engendered problems in nitrogenous waste excretion. Nitrogen is a fundamental component of amino acids, proteins, and nucleic acids, and the degradation of these nitrogen-containing compounds releases ammonia. Ammonia is toxic and must be removed. Fishes in water excrete ammonia as the major nitrogenous waste through gills, but gills of air-breathing fishes are modified for air-breathing or largely replaced by air-breathing organs. Notably, fishes emerged from water can no longer excrete ammonia effectively because of a lack of water to flush the gills. Hence, ancient fishes that participated in water-land transition must have developed means to deal with ammonia toxicity. Extant air-breathing fishes, particularly amphibious ones, can serve as models to examine adaptations which might have facilitated the emergence of ancient fishes from water. Some of these fishes can actively emerge from water and display complex behaviors on land, while a few can burrow into mud and survive for years during drought. Many of them are equipped with mechanisms to ameliorate ammonia toxicity during emersion. In this review, the mechanisms adopted by air-breathing fishes to deal with ammonia toxicity during emersion were organized into seven disparate strategies. In addition, eight extant air-breathing fishes with distinctive terrestrial behaviors and peculiar natural habitats were selected to describe in detail how these seven strategies could be adopted in disparate combinations to ameliorate ammonia toxicity during emersion.
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Kosenko EA, Tikhonova LA, Alilova GA, Montoliu C, Barreto GE, Aliev G, Kaminsky YG. Portacaval shunting causes differential mitochondrial superoxide production in brain regions. Free Radic Biol Med 2017; 113:109-118. [PMID: 28964916 DOI: 10.1016/j.freeradbiomed.2017.09.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 09/08/2017] [Accepted: 09/25/2017] [Indexed: 01/23/2023]
Abstract
The portacaval shunting (PCS) prevents portal hypertension and recurrent bleeding of esophageal varices. On the other hand, it can induce chronic hyperammonemia and is considered to be the best model of mild hepatic encephalopathy (HE). Pathogenic mechanisms of HE and dysfunction of the brain in hyperammonemia are not fully elucidated, but it was originally suggested that the pathogenetic defect causes destruction of antioxidant defense which leads to an increase in the production of reactive oxygen species (ROS) and the occurrence of oxidative stress. In order to gain insight into the pathogenic mechanisms of HE in the brain tissue, we investigated the effects of PCS in rats on free radicals production and activity levels of antioxidant and prooxidant enzymes in mitochondria isolated from different brain areas. We found that O2·- production, activities of Mn-superoxide dismutase (Mn-SOD), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione transferase (GT), nitric oxide synthase (NOS), and levels of carbonylated proteins differed between the four brain regions both in the amount and response to PCS. In PCS rats, Mn-SOD activity in the cerebellum was significantly decreased, and remained unchanged in the neocortex, hippocampus and striatum compared with that in sham-operated animals. Among the four brain regions in control rats, the levels of the carbonyl groups in mitochondrial proteins were maximal in the cerebellum. 4 weeks after PCS, the content of carbonylated proteins were higher only in mitochondria of this brain region. Under control conditions, O2·- production by submitochondrial particles in the cerebellum was significantly higher than in other brain regions, but was significantly increased in each brain region from PCS animals. Indeed, the production of O2·- by submitochondrial particles correlated with mitochondrial ammonia levels in the four brain regions of control and PCS-animals. These findings are the first to suggest that in vivo levels of ammonia in the brain directly affect the rate of mitochondrial O2·- production.
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Affiliation(s)
- Elena A Kosenko
- Institute of Theoretical and Experimental Biophysics, Pushchino, Russia.
| | | | - Gubidat A Alilova
- Institute of Theoretical and Experimental Biophysics, Pushchino, Russia
| | - Carmina Montoliu
- Fundación Investigación Hospital Clínico, Instituto Investigación Sanitaria-INCLIVA, Valencia, Spain
| | - George E Barreto
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá D.C., Colombia; Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago, Chile
| | - Gjumrakch Aliev
- GALLY International Biomedical Research Institute Inc., 7733 Louis Pasteur Drive, #330, San Antonio, TX 78229, USA; School of Health Science and Healthcare Administration, University of Atlanta, E. Johns Crossing, #175, Johns Creek, GA 30097, USA.
| | - Yury G Kaminsky
- Institute of Theoretical and Experimental Biophysics, Pushchino, Russia
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12
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Methamphetamine: Effects on the brain, gut and immune system. Pharmacol Res 2017; 120:60-67. [DOI: 10.1016/j.phrs.2017.03.009] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 02/08/2017] [Accepted: 03/07/2017] [Indexed: 12/31/2022]
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13
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Galland F, Negri E, Da Ré C, Fróes F, Strapazzon L, Guerra MC, Tortorelli LS, Gonçalves CA, Leite MC. Hyperammonemia compromises glutamate metabolism and reduces BDNF in the rat hippocampus. Neurotoxicology 2017; 62:46-55. [PMID: 28506823 DOI: 10.1016/j.neuro.2017.05.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 03/31/2017] [Accepted: 05/11/2017] [Indexed: 12/31/2022]
Abstract
Ammonia is putatively the major toxin associated with hepatic encephalopathy (HE), a neuropsychiatric manifestation that results in cognitive impairment, poor concentration and psychomotor alterations. The hippocampus, a brain region involved in cognitive impairment and depressive behavior, has been studied less than neocortical regions. Herein, we investigated hippocampal astrocyte parameters in a hyperammonemic model without hepatic lesion and in acute hippocampal slices exposed to ammonia. We also measured hippocampal BDNF, a neurotrophin commonly related to synaptic plasticity and cognitive deficit, and peripheral S100B protein, used as a marker for brain damage. Hyperammonemia directly impaired astrocyte function, inducing a decrease in glutamate uptake and in the activity of glutamine synthetase, in turn altering the glutamine-glutamate cycle, glutamatergic neurotransmission and ammonia detoxification itself. Hippocampal BDNF was reduced in hyperammonemic rats via a mechanism that may involve astrocyte production, since the same effect was observed in astrocyte cultures exposed to ammonia. Ammonia induced a significant increase in S100B secretion in cultured astrocytes; however, no significant changes were observed in the serum or in cerebrospinal fluid. Data demonstrating hippocampal vulnerability to ammonia toxicity, particularly due to reduced glutamate uptake activity and BDNF content, contribute to our understanding of the neuropsychiatric alterations in HE.
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Affiliation(s)
- Fabiana Galland
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
| | - Elisa Negri
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
| | - Carollina Da Ré
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
| | - Fernanda Fróes
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
| | - Liliane Strapazzon
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
| | - Maria Cristina Guerra
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
| | - Lucas Silva Tortorelli
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
| | - Carlos-Alberto Gonçalves
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
| | - Marina Concli Leite
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
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14
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Ashkani-Esfahani S, Bagheri F, Emami Y, Esmaeilzadeh E, Azarpira N, Hassanabadi N, Keshtkar M, Farjam M, Koohi-Hosseinabadi O, Noorafshan A. Protective Effects of Co-Enzyme Q10 on Thioacetamide-Induced Acute Liver Damage and Its Correlation With Behavioral, Biochemical, and Pathological Factors. IRANIAN RED CRESCENT MEDICAL JOURNAL 2016; 18:e29166. [PMID: 28058114 PMCID: PMC5192999 DOI: 10.5812/ircmj.29166] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 08/29/2015] [Accepted: 09/26/2015] [Indexed: 12/25/2022]
Abstract
Background Acute liver damage may be followed by biochemical, behavioral, and pathological alterations, which can result in serious complications and even death. Objectives In this experimental study we determined whether coenzyme Q10 (CoQ10), a common supplementary medicine known to have protective, antioxidative, and anti-inflammatory effects in cells, has any protective effect against thioacetamide (TAA)-induced liver damage and its related neurobehavioral alterations in rats. Materials and Methods In this experimental study forty-eight Wistar rats were divided randomly into four groups (n = 12): C1 was the control group; C2 received a single-dose of TAA (350mg/kg; intraperitoneally) without any other treatment; E1 received TAA + 5 mg/kg CoQ10 (intraperitoneally); and E2 received TAA + 10 mg/kg CoQ10. After sacrificing the rats, liver enzymes and plasma-ammonia (NH4) were measured and histopathological analyses of the livers were carried out. Elevated-plus-maze, open-field, and forced-swimming tests were also performed to investigate behavioral correlations. Results The serum levels of alanine-aminotransferase (ALT), aspartate-aminotransferase (AST), and NH4 show significant increases (P < 0.05). The groups treated with CoQ10 were shown to have significantly lower clinical grade of encephalopathy (P = 0.001), higher locomotor activity (P = 0.000), and lower levels of depression (P = 0.000). Furthermore, it was also shown that CoQ10 treatment may lead to significant decreases in scores of centrilobular necrosis, apoptosis, inflammatory cell infiltration, vacuolization, and liver necrosis (P < 0.05). Conclusions Overall, CoQ10 was determined to have positive effects on liver injury and its related behavioral and biochemical changes.
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Affiliation(s)
| | - Fereshteh Bagheri
- Student Research Committee, Shiraz University of Medical Sciences, Shiraz, IR Iran
| | - Yasaman Emami
- Student Research Committee, Shiraz University of Medical Sciences, Shiraz, IR Iran
| | - Elmira Esmaeilzadeh
- Student Research Committee, Shiraz University of Medical Sciences, Shiraz, IR Iran
| | - Negar Azarpira
- Organ Transplant Research Center, Namazi Hospital, Shiraz University of Medical Sciences, Shiraz, IR Iran
| | - Nazila Hassanabadi
- Student Research Committee, Shiraz University of Medical Sciences, Shiraz, IR Iran
| | - Marzieh Keshtkar
- International Branch, Shiraz University of Medical Sciences, Kish, IR Iran
| | - Mojtaba Farjam
- Department Of Pharmacology, Fasa University of Medical Sciences, Shiraz, IR Iran
| | - Omid Koohi-Hosseinabadi
- Center of Comparative and Experimental Medicine, Shiraz University of Medical Sciences, Shiraz, IR Iran
| | - Ali Noorafshan
- Histomorphometry and Stereology Research Centre, Shiraz University of Medical Sciences, Shiraz, IR Iran
- Corresponding Author: Ali Noorafshan, Histomorphometry and Stereology Research Centre, Shiraz University of Medical Sciences, Shiraz, IR Iran. Tel: +98-9173397040, Fax: +98-7136262034, E-mail:
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15
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Cittolin-Santos GF, de Assis AM, Guazzelli PA, Paniz LG, da Silva JS, Calcagnotto ME, Hansel G, Zenki KC, Kalinine E, Duarte MM, Souza DO. Guanosine Exerts Neuroprotective Effect in an Experimental Model of Acute Ammonia Intoxication. Mol Neurobiol 2016; 54:3137-3148. [PMID: 27052954 DOI: 10.1007/s12035-016-9892-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Accepted: 03/28/2016] [Indexed: 12/20/2022]
Abstract
The nucleoside guanosine (GUO) increases glutamate uptake by astrocytes and acts as antioxidant, thereby providing neuroprotection against glutamatergic excitotoxicity, as we have recently demonstrated in an animal model of chronic hepatic encephalopathy. Here, we investigated the neuroprotective effect of GUO in an acute ammonia intoxication model. Adult male Wistar rats received an intraperitoneal (i.p.) injection of vehicle or GUO 60 mg/kg, followed 20 min later by an i.p. injection of vehicle or 550 mg/kg of ammonium acetate. Afterwards, animals were observed for 45 min, being evaluated as normal, coma (i.e., absence of corneal reflex), or death status. In a second cohort of rats, video-electroencephalogram (EEG) recordings were performed. In a third cohort of rats, the following were measured: (i) plasma levels of glucose, transaminases, and urea; (ii) cerebrospinal fluid (CSF) levels of ammonia, glutamine, glutamate, and alanine; (iii) glutamate uptake in brain slices; and (iv) brain redox status and glutamine synthetase activity in cerebral cortex. GUO drastically reduced the lethality rate and the duration of coma. Animals treated with GUO had improved EEG traces, decreased CSF levels of glutamate and alanine, lowered oxidative stress in the cerebral cortex, and increased glutamate uptake by astrocytes in brain slices compared with animals that received vehicle prior to ammonium acetate administration. This study provides new evidence on mechanisms of guanine-derived purines in their potential modulation of glutamatergic system, contributing to GUO neuroprotective effects in a rodent model of by acute ammonia intoxication.
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Affiliation(s)
- G F Cittolin-Santos
- Postgraduate Program in Biological Sciences: Biochemistry, ICBS, Federal University of Rio Grande do Sul, Porto Alegre, RS, 90035-003, Brazil
| | - A M de Assis
- Postgraduate Program in Biological Sciences: Biochemistry, ICBS, Federal University of Rio Grande do Sul, Porto Alegre, RS, 90035-003, Brazil
| | - P A Guazzelli
- Postgraduate Program in Biological Sciences: Biochemistry, ICBS, Federal University of Rio Grande do Sul, Porto Alegre, RS, 90035-003, Brazil
| | - L G Paniz
- Postgraduate Program in Biological Sciences: Biochemistry, ICBS, Federal University of Rio Grande do Sul, Porto Alegre, RS, 90035-003, Brazil
| | - J S da Silva
- Postgraduate Program in Biological Sciences: Biochemistry, ICBS, Federal University of Rio Grande do Sul, Porto Alegre, RS, 90035-003, Brazil
| | - M E Calcagnotto
- Postgraduate Program in Biological Sciences: Biochemistry, ICBS, Federal University of Rio Grande do Sul, Porto Alegre, RS, 90035-003, Brazil.,Department of Biochemistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, 90035-003, Brazil
| | - G Hansel
- Postgraduate Program in Biological Sciences: Biochemistry, ICBS, Federal University of Rio Grande do Sul, Porto Alegre, RS, 90035-003, Brazil
| | - K C Zenki
- Postgraduate Program in Biological Sciences: Biochemistry, ICBS, Federal University of Rio Grande do Sul, Porto Alegre, RS, 90035-003, Brazil.,Department of Physiology, Federal University of Sergipe, São Cristovão, SE, 49100-000, Brazil
| | - E Kalinine
- Postgraduate Program in Biological Sciences: Biochemistry, ICBS, Federal University of Rio Grande do Sul, Porto Alegre, RS, 90035-003, Brazil.,Department of Physiology, Federal University of Sergipe, São Cristovão, SE, 49100-000, Brazil
| | - M M Duarte
- Health Sciences Center, Lutheran University of Brazil (ULBRA), Campus Santa Maria, Santa Maria, RS, 97020-001, Brazil
| | - D O Souza
- Postgraduate Program in Biological Sciences: Biochemistry, ICBS, Federal University of Rio Grande do Sul, Porto Alegre, RS, 90035-003, Brazil. .,Department of Biochemistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, 90035-003, Brazil.
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16
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Saito M, Hirano H, Yano Y, Momose K, Yoshida M, Azuma T. Serum level of taurine would be associated with the amelioration of minimal hepatic encephalopathy in cirrhotic patients. Hepatol Res 2016. [PMID: 26224109 DOI: 10.1111/hepr.12565] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
AIM A variety of treatment modalities including L-carnitine have been tried for cirrhotic patients with minimal hepatic encephalopathy (MHE), which improved MHE for some patients, but were not effective for the other patients. We aimed to identify pre-therapeutic independent factors to predict the amelioration of MHE after L-carnitine treatment. METHODS We performed a prospective cohort study on a total of 64 consecutive outpatients of cirrhotic patients who underwent blood biochemical examinations and neuropsychiatric (NP) test at Kobe University Hospital. MHE patients diagnosed by the NP test were p.o. administrated L-carnitine for 3 months. The patients with and without MHE amelioration were compared, and the independent factors were statistically examined. Predictive scoring systems of the amelioration of MHE were established using multivariate logistic regression. RESULTS The amelioration of MHE was found in 45.8% of MHE patients. Serum taurine before the treatment was the best predictive factor of the amelioration of MHE (P = 0.046). The predictive model using serum taurine discriminated well between patients with and without the amelioration of MHE (area under the receiver-operator curve, 0.748; 95% confidence interval, 0.531-0.901). The predictive scores of the amelioration of MHE enable the patient-specific probability to be easily looked up. CONCLUSION Serum taurine before L-carnitine treatment was shown to be an independent factor associated with the amelioration of MHE 3 months after the treatment. The easy pre-therapeutic prediction of MHE amelioration after L-carnitine treatment would help in improving awareness of the selection of MHE patients with good response to L-carnitine, thus being beneficial from a financial perspective.
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Affiliation(s)
- Masaya Saito
- Division of Gastroenterology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Hirotaka Hirano
- Division of Gastroenterology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yoshihiko Yano
- Division of Gastroenterology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.,Center for Infectious Diseases, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kenji Momose
- Division of Gastroenterology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Masaru Yoshida
- Division of Gastroenterology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.,Division of Metabolomics Research, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Takeshi Azuma
- Division of Gastroenterology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
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17
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Marano M, Vespasiani Gentilucci U, Altamura C, Siotto M, Squitti R, Bucossi S, Quintiliani L, Migliore S, Greco F, Scarciolla L, Quattrocchi CC, Picardi A, Vernieri F. Altered metal metabolism in patients with HCV-related cirrhosis and hepatic encephalopathy. Metab Brain Dis 2015; 30:1445-52. [PMID: 26307419 DOI: 10.1007/s11011-015-9721-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2015] [Accepted: 08/21/2015] [Indexed: 12/13/2022]
Abstract
Dysfunctional metal homeostasis contributes to oxidative stress and neuronal damage. These have been implicated in hepatic encephalopathy pathogenesis. To investigate whether altered metal metabolism is associated with hepatic encephalopathy. Twenty-one controls and 34 HCV-cirrhotic patients (ENC/NEC patients according to presence/absence of previous overt episodes of hepatic encephalopathy) and a control group were studied. Serum iron, copper, ceruloplasmin, ceruloplasmin activity, transferrin, and ceruloplasmin/transferrin ratio were determined. Neuropsychological tests were performed by the repeatable battery of neuropsychological status. Magnetic resonance assessed basal ganglia volumes and metal deposition (pallidal index and T2*). Cirrhotic patients performed worse than controls at cognitive tests, especially ENC patients,. At biochemical analysis copper concentrations, ceruloplasmin activity and transferrin levels were lower in ENC than in NEC patients and controls (p < 0.05 and p < 0.01, respectively). Ceruloplasmin/transferrin ratio was higher in ENC compared to NEC patients (p < 0.05), and controls (p < 0.01). By brain magnetic resonance, ENC patients showed reduced caudate and globus pallidus volumes compared to controls (p < 0.05), and ENC and NEC patients an increased pallidal index compared to controls (p < 0.01). In ENC patients, ceruloplasmin activity correlated with caudate volume and pallidal index (ρ = 0.773 and ρ = -0.683, p < 0.05). Altered metal metabolism likely contributes to cirrhotic hepatic encephalopathy.
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Affiliation(s)
- Massimo Marano
- Neurology, Campus Bio-Medico University of Rome, Via Alvaro del Portillo 200, 00128, Rome, Italy.
| | - Umberto Vespasiani Gentilucci
- Internal Medicine and Hepatology, Campus Bio-Medico University of Rome, Via Alvaro del Portillo 200, 00128, Rome, Italy
| | - Claudia Altamura
- Neurology, Campus Bio-Medico University of Rome, Via Alvaro del Portillo 200, 00128, Rome, Italy
| | | | - Rosanna Squitti
- Fatebenefratelli Foundation, AFaR Division, Fatebenefratelli Hospital, Isola Tiberina, Rome, Italy
- Laboratorio di Neurodegenerazione, IRCCS San Raffaele Pisana, Rome, Italy
| | - Serena Bucossi
- Laboratorio di Neurodegenerazione, IRCCS San Raffaele Pisana, Rome, Italy
| | - Livia Quintiliani
- Clinical psychology, Campus Bio-Medico University of Rome, Via Alvaro del Portillo 200, 00128, Rome, Italy
| | - Simone Migliore
- Clinical psychology, Campus Bio-Medico University of Rome, Via Alvaro del Portillo 200, 00128, Rome, Italy
| | - Federico Greco
- Radiology, Campus Bio-Medico University of Rome, Via Alvaro del Portillo 200, 00128, Rome, Italy
| | - Laura Scarciolla
- Radiology, Campus Bio-Medico University of Rome, Via Alvaro del Portillo 200, 00128, Rome, Italy
| | - Carlo Cosimo Quattrocchi
- Radiology, Campus Bio-Medico University of Rome, Via Alvaro del Portillo 200, 00128, Rome, Italy
| | - Antonio Picardi
- Internal Medicine and Hepatology, Campus Bio-Medico University of Rome, Via Alvaro del Portillo 200, 00128, Rome, Italy
| | - Fabrizio Vernieri
- Neurology, Campus Bio-Medico University of Rome, Via Alvaro del Portillo 200, 00128, Rome, Italy
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18
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Bobermin LD, Wartchow KM, Flores MP, Leite MC, Quincozes-Santos A, Gonçalves CA. Ammonia-induced oxidative damage in neurons is prevented by resveratrol and lipoic acid with participation of heme oxygenase 1. Neurotoxicology 2015; 49:28-35. [PMID: 26003724 DOI: 10.1016/j.neuro.2015.05.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 05/14/2015] [Accepted: 05/15/2015] [Indexed: 12/29/2022]
Abstract
Ammonia is a metabolite that, at high concentrations, is implicated in neurological disorders, such as hepatic encephalopathy (HE), which is associated with acute or chronic liver failure. Astrocytes are considered the primary target of ammonia toxicity in the central nervous system (CNS) because glutamine synthetase (GS), responsible for ammonia metabolism in CNS, is an astrocytic enzyme. Thus, neuronal dysfunction has been associated as secondary to astrocytic impairment. However, we demonstrated that ammonia can induce direct effects on neuronal cells. The cell viability was decreased by ammonia in SH-SY5Y cells and cerebellar granule neurons. In addition, ammonia induced increased reactive oxygen species (ROS) production and decreased GSH intracellular content, the main antioxidant in CNS. As ammonia neurotoxicity is strongly associated with oxidative stress, we also investigated the potential neuroprotective roles of the antioxidants, resveratrol (RSV) and lipoic acid (LA), against ammonia toxicity in cerebellar granule neurons. RSV and LA were able to prevent the oxidative damage induced by ammonia, maintaining the levels of ROS production and GSH close to basal values. Both antioxidants also decreased ROS production and increased GSH content under basal conditions (in the absence of ammonia). Moreover, we showed that heme oxygenase 1 (HO1), a protein associated with protection against stress conditions, is involved in the beneficial effects of RSV and LA in cerebellar granule neurons. Thus, this study reinforces the neuroprotective effects of RSV and LA. Although more studies in vivo are required, RSV and LA could represent interesting therapeutic strategies for the management of HE.
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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, RS, Brazil.
| | - Krista Minéia Wartchow
- Department of Biochemistry, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Marianne Pires Flores
- Department of Biochemistry, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Marina Concli Leite
- Department of Biochemistry, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - André Quincozes-Santos
- Department of Biochemistry, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Carlos-Alberto Gonçalves
- Department of Biochemistry, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil
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19
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Zhang J, Zhang M, Sun B, Li Y, Xu P, Liu C, Liu L, Liu X. Hyperammonemia enhances the function and expression of P-glycoprotein and Mrp2 at the blood-brain barrier through NF-κB. J Neurochem 2014; 131:791-802. [PMID: 25200138 DOI: 10.1111/jnc.12944] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Revised: 08/08/2014] [Accepted: 09/05/2014] [Indexed: 01/17/2023]
Abstract
Ammonia is considered to be the main neurotoxin responsible for hepatic encephalopathy resulting from liver failure. Liver failure has been reported to alter expression and activity of P-glycoprotein (P-gp) and multidrug resistance-associated protein 2 (Mrp2) at the blood-brain barrier (BBB). The aim of this study was to investigate whether ammonia is involved in abnormalities of expression and activity of P-gp and Mrp2 at the BBB. Hyperammonemic rats were developed by an intraperitoneal injection of ammonium acetate (NH4 Ac, 4.5 mmol/kg). Results showed that Mrp2 function markedly increased in cortex and hippocampus of rats at 6 h following NH4 Ac administration. Significant increase in function of P-gp was observed in hippocampus of rats. Meanwhile, such alterations were in line with the increase in mRNA and protein levels of P-gp and Mrp2. Significant increase in levels of nuclear amount of nuclear factor-κB (NF-κB) p65 was also observed. Primarily cultured rat brain microvessel endothelial cells (rBMECs) were used for in vitro study. Data indicated that 24 h exposure to ammonia significantly increased function and expression of P-gp and Mrp2 in rBMECs, accompanied with activation of NF-κB. Furthermore, such alterations induced by ammonia were reversed by NF-κB inhibitor. In conclusion, this study demonstrates that hyperammonemia increases the function and expression of P-gp and Mrp2 at the BBB via activating NF-κB pathway. Hyperammonemia, a proverbial main factor responsible for neurocognitive disorder and blood-brain barrier (BBB) dysfunction resulting from liver failure, could increase the expression and activity of P-glycoprotein and multidrug resistance-associated protein 2 (Mrp2) at the BBB both in vivo and in vitro. Furthermore, the NF-κB activation stimulated by hyperammonemia may be the potential mechanism underlying such abnormalities induced by hyperammonemia.
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Affiliation(s)
- Ji Zhang
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing, China
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20
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Cichoż-Lach H, Michalak A. Oxidative stress as a crucial factor in liver diseases. World J Gastroenterol 2014; 20:8082-8091. [PMID: 25009380 PMCID: PMC4081679 DOI: 10.3748/wjg.v20.i25.8082] [Citation(s) in RCA: 707] [Impact Index Per Article: 70.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 04/23/2014] [Indexed: 02/06/2023] Open
Abstract
Redox state constitutes an important background of numerous liver disorders. The redox state participates in the course of inflammatory, metabolic and proliferative liver diseases. Reactive oxygen species (ROS) are primarily produced in the mitochondria and in the endoplasmic reticulum of hepatocytes via the cytochrome P450 enzymes. Under the proper conditions, cells are equipped with special molecular strategies that control the level of oxidative stress and maintain a balance between oxidant and antioxidant particles. Oxidative stress represents an imbalance between oxidant and antioxidant agents. Hepatocytic proteins, lipids and DNA are among the cellular structures that are primarily affected by ROS and reactive nitrogen species. The process results in structural and functional abnormalities in the liver. Thus, the phenomenon of oxidative stress should be investigated for several reasons. First, it may explain the pathogenesis of various liver disorders. Moreover, monitoring oxidative markers among hepatocytes offers the potential to diagnose the degree of liver damage and ultimately to observe the response to pharmacological therapies. The present report focuses on the role of oxidative stress in selected liver diseases.
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21
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Farjam M, Mehrabani D, Abbassnia F, Tanideh N, Imanieh MH, Pakbaz S, Ashraf MJ, Panjehshahin MR, Dehdab S. The healing effect of Curcuma longa on liver in experimental acute hepatic encephalopathy of rat. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/s00580-014-1883-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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22
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Chepkova AN, Sergeeva OA, Haas HL. Alterations of corticostriatal plasticity by ammonium and rescue by green tea polyphenols. Arch Biochem Biophys 2013; 536:176-82. [DOI: 10.1016/j.abb.2013.02.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 01/31/2013] [Accepted: 02/05/2013] [Indexed: 01/22/2023]
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23
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Wang QM, Yin XY, Duan ZJ, Guo SB, Sun XY. Role of the heme oxygenase/carbon monoxide pathway in the pathogenesis and prevention of hepatic encephalopathy. Mol Med Rep 2013; 8:67-74. [PMID: 23670786 DOI: 10.3892/mmr.2013.1472] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 04/29/2013] [Indexed: 11/05/2022] Open
Abstract
Hepatic encephalopathy (HE) is a severe complication of liver cirrhosis and its pathogenesis has yet to be fully elucidated. Previous studies have demonstrated that heme oxygenase-1 (HO-1) is important in the induction of liver cirrhosis. The present study aimed to investigate the role of HO-1 in the pathogenesis of HE. Rats were divided into 5 treatment groups; sham, bile duct ligation (BDL), HE, zinc protoporphyrin (ZnPP) and cobalt protoporphyrin (CoPP). The levels of HO-1 were examined by western blotting and quantitative real-time PCR (qRT-PCR). Serum levels of carboxyhemoglobin (COHb), ammonia levels in the plasma and brain, brain water content and portal vein pressure (PVP) were also quantified. Aquaporin-4 expression levels were measured by immunohistochemistry and qRT-PCR. The results demonstrated that the levels of HO-1 in the brain and the serum levels of COHb were significantly increased in the HE group compared with the BDL group. Brain water content, PVP and ammonia levels in the plasma and brain were increased in the HE and CoPP groups; however, these were reduced following the treatment with ZnPP. The levels of AQP-4 expression and oxidative stress in the brain were reduced following treatment with ZnPP and increased following treatment with CoPP. In conclusion, following the inhibition of HO-1 expression, treatment with ZnPP improved HE due to reducing the expression levels of AQP-4 and oxidative stress. Therefore, ZnPP treatment may represent a novel therapeutic approach for HE.
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Affiliation(s)
- Qiu-Ming Wang
- Department of Gastroenterology, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116011, PR China
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Wen S, Schroeter A, Klöcker N. Synaptic plasticity in hepatic encephalopathy - a molecular perspective. Arch Biochem Biophys 2013; 536:183-8. [PMID: 23624147 DOI: 10.1016/j.abb.2013.04.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 04/13/2013] [Accepted: 04/15/2013] [Indexed: 01/04/2023]
Abstract
Hepatic encephalopathy (HE)(1) is a common neuropsychiatric complication of both acute and chronic liver disease. Clinical symptoms may include motor disturbances and cognitive dysfunction. Available animal models of HE mimic the deficits in cognitive performance including the impaired ability to learn and memorize information. This review explores the question how HE might affect cognitive functions at molecular levels. Both acute and chronic models of HE constrain the plasticity of glutamatergic neurotransmission. Thus, long-lasting activity-dependent changes in synaptic efficiency, known as long-term potentiation (LTP) and long-term depression (LTD) are significantly impeded. We discuss molecules and signal transduction pathways of LTP and LTD that are targeted by experimental HE, with a focus on ionotropic glutamate receptors of the AMPA-subtype. Finally, a novel strategy of functional proteomic analysis is presented, which, if applied differentially, may provide molecular insight into disease-related dysfunction of membrane protein complexes, i.e. disturbed ionotropic glutamate receptor signaling in HE.
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Affiliation(s)
- Shuping Wen
- Institute of Neural and Sensory Physiology, Medical Faculty, University of Düsseldorf D-40225 Düsseldorf, Germany
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Palomero-Gallagher N, Zilles K. Neurotransmitter receptor alterations in hepatic encephalopathy: a review. Arch Biochem Biophys 2013; 536:109-21. [PMID: 23466244 DOI: 10.1016/j.abb.2013.02.010] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 02/18/2013] [Accepted: 02/19/2013] [Indexed: 01/07/2023]
Abstract
Hepatic encephalopathy (HE), a complex neuropsychiatric syndrome with symptoms ranging from subtle neuropsychiatric and motor disturbances to deep coma and death, is thought to be a clinical manifestation of a low-grade cerebral oedema associated with an altered neuron-astrocyte crosstalk and exacerbated by hyperammonemia and oxidative stress. These events are tightly coupled with alterations in neurotransmission, either in a causal or a causative manner, resulting in a net increase of inhibitory neurotransmission. Therefore, research focussed mainly on the potential role of γ-aminobutyric acid-(GABA) or glutamate-mediated neurotransmission in the pathophysiology of HE, though roles for other neurotransmitters (e.g. serotonin, dopamine, adenosine and histamine) or for neurosteroids or endogenous benzodiazepines have also been suggested. Therefore, we here review HE-related alterations in neurotransmission, focussing on changes in the levels of classical neurotransmitters and the neuromodulator adenosine, variations in the activity and/or concentrations of key enzymes involved in their metabolism, as well as in the densities of their receptors.
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Pretransplant Neurological Presentation and Severe Posttransplant Brain Injury in Patients With Acute Liver Failure. Transplantation 2012; 94:768-74. [DOI: 10.1097/tp.0b013e3182620596] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Occludin dislocation in brain capillary endothelium of rats with bile duct ligation induced cholestasis. Neurosci Lett 2012; 528:180-4. [PMID: 22985504 DOI: 10.1016/j.neulet.2012.08.066] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 07/26/2012] [Accepted: 08/09/2012] [Indexed: 01/24/2023]
Abstract
The present study used a rat model with bile duct ligation to examine the effect of cholestasis, to the localization of occludin in brain capillary endothelium by means of electronic microscopy. The results demonstrated a dislocation of occludin away from the tight junction sites of brain endothelial cells. A significant increase of the occludin-interendothelial cleft distance was demonstrated in the midbrain and the cerebellum samples but not in the frontal cortex, compared to the control group samples. These findings imply a brain region selective derangement of occludin in response to liver disease.
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Chepkova AN, Selbach O, Haas HL, Sergeeva OA. Ammonia-induced deficit in corticostriatal long-term depression and its amelioration by zaprinast. J Neurochem 2012; 122:545-56. [PMID: 22639911 DOI: 10.1111/j.1471-4159.2012.07806.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hyperammonemia is a major pathophysiological factor in encephalopathies associated with acute and chronic liver failure. On mouse brain slice preparations, we analyzed the effects of ammonia on the characteristics of corticostriatal long-term depression (LTD) induced by electrical stimulation of cortical input or pharmacological activation of metabotropic glutamate receptors. Long exposure of neostriatal slices to ammonium chloride impaired the induction and/or expression of all studied forms of LTD. This impairment was reversed by the phosphodiesterase inhibitor zaprinast implying lowered cGMP signaling in LTD suppression. Polyphenols from green tea rescued short-term corticostriatal plasticity, but failed to prevent the ammonia-induced deficit of LTD. Zaprinast counteracts the ammonia-induced impairment of long-term corticostriatal plasticity and may thus improve fine motor skills and procedural learning in hepatic encephalopathy.
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Affiliation(s)
- Aisa N Chepkova
- Department of Neurophysiology, Medical Faculty, Heinrich-Heine-University, Dusseldorf, Germany
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Moderate grade hyperammonemia induced concordant activation of antioxidant enzymes is associated with prevention of oxidative stress in the brain slices. Neurochem Res 2011; 37:171-81. [PMID: 21922254 DOI: 10.1007/s11064-011-0596-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 08/30/2011] [Accepted: 09/08/2011] [Indexed: 10/17/2022]
Abstract
Acute hyperammonemia (HA) induced oxidative stress in the brain is considered to play critical roles in the neuropathology of end stage hepatic encephalopathy (HE). Moderate grade HA led minimal/moderate type HE is more common in the patients with chronic liver failure. However, implication of oxygen free radical ([Formula: see text]) based oxidative mechanisms remain to be defined during moderate grade HA. This article describes profiles of all the antioxidant enzymes Vis a Vis status of oxidative stress/damage in the brain slices exposed to 0.1-1 mM ammonia, reported to exist in the brain of animals with chronic liver failure and in liver cirrhotic patients. Superoxide dismutase catalyzes the first step of antioxidant mechanism and, with concerted activity of catalase, neutralizes [Formula: see text] produced in the cells. Both these enzymes remained unchanged up to 0.2-0.3 mM ammonia, however, with significant increments (P < 0.01-0.001) in the brain slices exposed to 0.5-1 mM ammonia. This was consistent with the similar pattern of production of reactive oxygen species in the brain slices. However, level of lipid peroxidation remained unchanged throughout the ammonia treatment. Synchronized activities of glutathione peroxidase and glutathione reductase regulate the level of glutathione to maintain reducing equivalents in the cells. The activities of both these enzymes also increased significantly in the brain slices exposed to 0.5-1 mM ammonia with concomitant increments in GSH/GSSG ratio and in the levels of total and protein bound thiol. The findings suggest resistance of brain cells from ammonia induced oxidative damage during moderate grade HA due to concordant activations of antioxidant enzymes.
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Assimakopoulos SF, Gogos C, Labropoulou-Karatza C. Could antioxidants be the “magic pill” for cirrhosis-related complications? A pathophysiological appraisal. Med Hypotheses 2011; 77:419-23. [DOI: 10.1016/j.mehy.2011.05.034] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Accepted: 05/29/2011] [Indexed: 12/12/2022]
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Atluri DK, Prakash R, Mullen KD. Pathogenesis, diagnosis, and treatment of hepatic encephalopathy. J Clin Exp Hepatol 2011; 1:77-86. [PMID: 25755319 PMCID: PMC3940085 DOI: 10.1016/s0973-6883(11)60126-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Accepted: 09/02/2011] [Indexed: 02/07/2023] Open
Abstract
Hepatic encephalopathy (HE) is a neuropsychiatric disorder seen in patients with advanced liver disease or porto-systemic shunts. Based on etiology and severity of HE, the World Congress of Gastroenterology has divided HE into categories and sub-categories. Many user-friendly computer-based neuropsychiatric tests are being validated for diagnosing covert HE. Currently, emphasis is being given to view HE deficits as a continuous spectrum rather than distinct stages. Ammonia is believed to play crucial role in pathogenesis of HE via astrocyte swelling and cerebral edema. However, evidence has been building up which supports the synergistic role of oxidative stress, inflammation and neurosteroids in pathogenesis of HE. At present, treatment of HE aims at decreasing the production and intestinal absorption of ammonia. But as the role of new pathogenetic mechanisms becomes clear, many potential new treatment strategies may become available for clinician.
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Key Words
- AAA, aromatic amino acid
- BAUR, brain ammonia utilization rate
- BCAA, branched-chain amino acids
- CFF, critical flicker fusion
- DBI, diazepam binding inhibitor
- DST, digit symbol test
- DWI, diffusion weighted imaging
- Diagnosis
- ECAD, extra-corporeal albumin dialysis
- EEC, electroencephalogram
- FLAIR, fluid attenuation inversion recovery
- HE, hepatic encephalopathy
- HESA, hepatic encephalopathy scoring algorithm
- ICT, inhibitory control test
- IL, interleukin
- LOLA, L-ornithine L-aspartate
- LTT, line tracing test
- MARS, molecular adsorbent reticulating system
- MHE, minimal hepatic encephalopathy
- MRI, magnetic resonance imaging
- NAC, N-acetyl cysteine
- NO, nitric oxide
- NS, neurosteroids
- NSAID, non-steroidal anti-inflammatory drugs
- ODN, octadecaneuropeptide
- OHE, overt hepatic encephalopathy
- PTBR, peripheral-type benzodiaze-pine receptor
- QOL, quality of life
- SDT, serial dotting test
- SEDACA, short epoch, dominant activity, and cluster analysis
- SIBO, small intestinal bacterial overgrowth
- SIRS, systemic inflammatory response syndrome
- SOD, Superoxide dismutase
- SONIC, spectrum of neurological impairment
- TLP, TransLocator Protein
- TNF, tumor necrosis factor
- hepatic encephalopathy
- pathogenesis
- treatment
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Affiliation(s)
| | | | - Kevin D Mullen
- Address for correspondence: Dr Kevin D Mullen, Gastroenterology Department, MetroHealth Medical Center, 2500 MetroHealth Drive, Cleveland, OH-44109, USA
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Skowrońska M, Albrecht J. Alterations of blood brain barrier function in hyperammonemia: an overview. Neurotox Res 2011; 21:236-44. [PMID: 21874372 PMCID: PMC3246587 DOI: 10.1007/s12640-011-9269-4] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 08/12/2011] [Accepted: 08/17/2011] [Indexed: 02/01/2023]
Abstract
Ammonia is a neurotoxin involved in the pathogenesis of neurological conditions associated with hyperammonemia, including hepatic encephalopathy, a condition associated with acute—(ALF) or chronic liver failure. This article reviews evidence that apart from directly affecting the metabolism and function of the central nervous system cells, ammonia influences the passage of different molecules across the blood brain barrier (BBB). A brief description is provided of the tight junctions, which couple adjacent cerebral capillary endothelial cells to each other to form the barrier. Ammonia modulates the transcellular passage of low-to medium-size molecules, by affecting their carriers located at the BBB. Ammonia induces interrelated aberrations of the transport of the large neutral amino acids and aromatic amino acids (AAA), whose influx is augmented by exchange with glutamine produced in the course of ammonia detoxification, and maybe also modulated by the extracellularly acting gamma-glutamyl moiety transferring enzyme, gamma-glutamyl-transpeptidase. Impaired AAA transport affects neurotransmission by altering intracerebral synthesis of catecholamines (serotonin and dopamine), and producing “false neurotransmitters” (octopamine and phenylethylamine). Ammonia also modulates BBB transport of the cationic amino acids: the nitric oxide precursor, arginine, and ornithine, which is an ammonia trap, and affects the transport of energy metabolites glucose and creatine. Moreover, ammonia acting either directly or in synergy with liver injury-derived inflammatory cytokines also evokes subtle increases of the transcellular passage of molecules of different size (BBB “leakage”), which appears to be responsible for the vasogenic component of cerebral edema associated with ALF.
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Affiliation(s)
- Marta Skowrońska
- Departament of Neurotoxicology, Mossakowski Medical Research Centre, Polish Academy of Sciences, 02-106 Warszawa, Pawińskiego 5, Poland
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Jayakumar AR, Valdes V, Norenberg MD. The Na-K-Cl cotransporter in the brain edema of acute liver failure. J Hepatol 2011; 54:272-8. [PMID: 21056502 DOI: 10.1016/j.jhep.2010.06.041] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Revised: 06/15/2010] [Accepted: 06/28/2010] [Indexed: 01/29/2023]
Abstract
BACKGROUND & AIMS Astrocyte swelling and brain edema associated with increased intracranial pressure are major complications of acute liver failure (ALF). The mechanism for such astrocyte swelling/brain edema, however, is not well understood. We recently found that ammonia, a key etiological factor in ALF, caused the activation of the Na-K-Cl cotransporter-1 (NKCC1) in cultured astrocytes, and that inhibition of such activation led to a reduction in astrocyte swelling, suggesting that NKCC1 activation may be an important factor in the mechanism of brain edema in ALF. To determine whether NKCC activation is also involved in brain edema in vivo, we examined whether NKCC activation occurs in the thioacetamide (TAA) rat model of ALF and determined whether treatment with the NKCC inhibitor bumetanide reduces the severity of brain edema in TAA-treated rats. METHODS Brain water content was measured using the gravimetric method. NKCC1 phosphorylation and protein expression were measured by Western blots. NKCC activity was measured in brain cortical slices. RESULTS NKCC activity was elevated in brain cortical slices of TAA-treated rats as compared to sham animals. Western blot analysis showed significant increases in total as well as phosphorylated (activated) NKCC1 protein expression in the cortical tissue. These findings were associated with a significant increase in brain water content which was attenuated by treatment with the NKCC inhibitor bumetanide. CONCLUSIONS Our studies suggest the involvement of NKCC in the development of brain edema in experimental ALF, and that targeting NKCC may represent a useful therapeutic strategy in humans with ALF.
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Affiliation(s)
- Arumugam R Jayakumar
- Department of Pathology, University of Miami, School of Medicine, Miami, FL 33101, USA
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Molecular targets of alcohol action: Translational research for pharmacotherapy development and screening. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 98:293-347. [PMID: 21199775 DOI: 10.1016/b978-0-12-385506-0.00007-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Alcohol abuse and dependence are multifaceted disorders with neurobiological, psychological, and environmental components. Research on other complex neuropsychiatric diseases suggests that genetically influenced intermediate characteristics affect the risk for heavy alcohol consumption and its consequences. Diverse therapeutic interventions can be developed through identification of reliable biomarkers for this disorder and new pharmacological targets for its treatment. Advances in the fields of genomics and proteomics offer a number of possible targets for the development of new therapeutic approaches. This brain-focused review highlights studies identifying neurobiological systems associated with these targets and possible pharmacotherapies, summarizing evidence from clinically relevant animal and human studies, as well as sketching improvements and challenges facing the fields of proteomics and genomics. Concluding thoughts on using results from these profiling technologies for medication development are also presented.
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Abstract
Hepatic encephalopathy is a complex and potentially reversible neuropsychiatric syndrome complicating acute or chronic liver disease. Clinical manifestations are multiple and varied, ranging from minimal neurological changes to coma. Ammonia is the main toxic substance involved in the pathogenesis of hepatic encephalopathy, although other mechanisms, such as modifications of the blood-brain barrier, disruptions in neurotransmission and abnormalities in GABAergic and benzodiazepine pathways may also play a role. The identification and treatment of precipitating factors is crucial in the management of patients with hepatic encephalopathy. Current treatments are based on reducing intestinal ammonia load by agents such as antibiotics or disaccharides, although their efficacy is yet to be clearly established.
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