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Ocaña-Sánchez MF, Soto-Ojeda GA, Cocotle-Ronzón Y, Soria-Fregozo C, Sánchez-Medina A, García-Rodríguez RV, Rodríguez-Landa JF, Corro-Méndez EJ, Hernández-Lozano M. Flaxseed Oil ( Linum usitatissimum) Prevents Cognitive and Motor Damage in Rats with Hyperammonemia. Nutrients 2023; 15:4550. [PMID: 37960203 PMCID: PMC10647672 DOI: 10.3390/nu15214550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 10/25/2023] [Accepted: 10/25/2023] [Indexed: 11/15/2023] Open
Abstract
Hyperammonemia is characterized by the excessive accumulation of ammonia in the body as a result of the loss of liver detoxification, leading to the development of hepatic encephalopathy (HE). These metabolic alterations carry cognitive and motor deficits and cause neuronal damage, with no effective treatment at present. In this study, we aimed to evaluate the effect of two subacute oral administrations of flaxseed oil (0.26 and 0.52 mL/kg) on short- and long-term memory, visuospatial memory, locomotor activity, motor coordination, and the neuronal morphology of the prefrontal cortex (PFC) via tests on Wistar rats with hyperammonemia. The goal was to identify its role in the regulation of cerebral edema, without liver damage causing cerebral failure. In contrast with an ammonium-rich diet, flaxseed oil and normal foods did not cause cognitive impairment or motor alterations, as evidenced in the short-term and visuospatial memory tests. Furthermore, the flaxseed oil treatment maintained a regular neuronal morphology of the prefrontal cortex, which represents a neuroprotective effect. We conclude that the oral administration of flaxseed oil prevents cognitive and motor impairments as well as neuronal alterations in rats with hyperammonemia, which supports the potential use of this oil to ameliorate the changes that occur in hepatic encephalopathy.
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Affiliation(s)
- Marcos F. Ocaña-Sánchez
- Programa de Doctorado en Ciencias Biomédicas, Centro de Investigaciones Biomédicas, Universidad Veracruzana, Xalapa 91190, Mexico
- Facultad de Química Farmacéutica Biológica, Universidad Veracruzana, Xalapa 91090, Mexico; (G.A.S.-O.); (Y.C.-R.)
| | - Gabriel A. Soto-Ojeda
- Facultad de Química Farmacéutica Biológica, Universidad Veracruzana, Xalapa 91090, Mexico; (G.A.S.-O.); (Y.C.-R.)
| | - Yolanda Cocotle-Ronzón
- Facultad de Química Farmacéutica Biológica, Universidad Veracruzana, Xalapa 91090, Mexico; (G.A.S.-O.); (Y.C.-R.)
| | - Cesar Soria-Fregozo
- Laboratorio Ciencias Biomédicas/área Histología y Psicobiología, Departamento de Ciencias de la Tierra y de la Vida, Centro Universitario de los Lagos, Universidad de Guadalajara, Lagos de Moreno 47460, Mexico;
| | - Alberto Sánchez-Medina
- Instituto de Química Aplicada, Universidad Veracruzana, Xalapa 91190, Mexico; (A.S.-M.); (R.V.G.-R.)
| | - Rosa V. García-Rodríguez
- Instituto de Química Aplicada, Universidad Veracruzana, Xalapa 91190, Mexico; (A.S.-M.); (R.V.G.-R.)
| | | | - Erick J. Corro-Méndez
- Facultad de Ciencias Biológicas y Agropecuarias, Universidad Veracruzana, Amatlán 94945, Mexico;
| | - Minerva Hernández-Lozano
- Facultad de Química Farmacéutica Biológica, Universidad Veracruzana, Xalapa 91090, Mexico; (G.A.S.-O.); (Y.C.-R.)
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Cudalbu C, Xin L, Marechal B, Lachat S, Zangas-Gheri F, Valenza N, Hanquinet S, McLin VA. High field brain proton magnetic resonance spectroscopy and volumetry in children with chronic, compensated liver disease - A pilot study. Anal Biochem 2023:115212. [PMID: 37356555 DOI: 10.1016/j.ab.2023.115212] [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: 03/10/2023] [Revised: 06/07/2023] [Accepted: 06/08/2023] [Indexed: 06/27/2023]
Abstract
BACKGROUND and rationale: There is increasing evidence that children or young adults having acquired liver disease in childhood display neurocognitive impairment which may become more apparent as they grow older. The molecular, cellular and morphological underpinnings of this clinical problem are incompletely understood. AIM Therefore, we used the advantages of highly-resolved proton magnetic resonance spectroscopy at ultra-high magnetic field to analyze the neurometabolic profile and brain morphometry of children with chronic, compensated liver disease, hypothesizing that with high field spectroscopy we would identify early evidence of rising brain glutamine and decreased myoinositol, such as has been described both in animals and humans with more significant liver disease. METHODS Patients (n = 5) and age-matched controls (n = 19) underwent 7T MR scans and short echo time 1H MR spectra were acquired using the semi-adiabatic SPECIAL sequence in two voxels located in gray and white matter dominated prefrontal cortex, respectively. A 3D MP2RAGE sequence was also acquired for brain volumetry and T1 mapping. Liver disease had to have developed at least 6 months before entering the study. Subjects underwent routine blood analysis and neurocognitive testing using validated methods within 3 months of MRI and MRS. RESULTS Five children currently aged 8-16 years with liver disease acquired in childhood were included. Baseline biological characteristics were similar among patients. There were no statistically significant differences between subjects and controls in brain metabolite levels or brain volumetry. Finally, there were minor neurocognitive fluctuations including attention deficit in one child, but none fell in the statistically significant range. CONCLUSION Children with chronic, compensated liver disease did not display an abnormal neurometabolic profile, neurocognitive abnormalities, or signal intensity changes in the globus pallidus. Despite the absence of neurometabolic changes, it is an opportunity to emphasize that it is only by developing the use of 1H MRS at high field in the clinical arena that we will understand the significance and generalizability of these findings in children with CLD. Attention deficit was observed in one child. Healthy children displayed neurometabolic regional differences as previously reported in adult subjects.
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Affiliation(s)
- Cristina Cudalbu
- CIBM Center for Biomedical Imaging, Switzerland; Animal Imaging and Technology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Lijing Xin
- CIBM Center for Biomedical Imaging, Switzerland; Animal Imaging and Technology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Benedicte Marechal
- Advanced Clinical Imaging Technology, Siemens Healthineers International AG, Lausanne, Switzerland; Department of Radiology, Lausanne University Hospital (CHUV) and University of Lausanne, Lausanne, Switzerland; LTS5, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Sarah Lachat
- Swiss Pediatric Liver Center, Pediatric Gastroenterology, Hepatology and Nutrition Unit, University Hospitals Geneva, Department of Pediatrics, Gynecology and Obstetrics, University of Geneva Medical School, Geneva, Switzerland
| | - Florence Zangas-Gheri
- Pediatric Neurology Unit, University Hospitals Geneva, Department of Pediatrics, Gynecology and Obstetrics, University of Geneva Medical School, Geneva, Switzerland
| | - Nathalie Valenza
- Pediatric Neurology Unit, University Hospitals Geneva, Department of Pediatrics, Gynecology and Obstetrics, University of Geneva Medical School, Geneva, Switzerland
| | - Sylviane Hanquinet
- Pediatric Radiology Unit, Radiology Division, Diagnostic Department, Children's Hospital, University Hospitals of Geneva, Switzerland
| | - Valérie A McLin
- Swiss Pediatric Liver Center, Pediatric Gastroenterology, Hepatology and Nutrition Unit, University Hospitals Geneva, Department of Pediatrics, Gynecology and Obstetrics, University of Geneva Medical School, Geneva, Switzerland.
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MR T1 mapping for quantifying brain manganese deposition in type C hepatic encephalopathy rats. Biometals 2021; 34:841-854. [PMID: 33928475 DOI: 10.1007/s10534-021-00311-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Accepted: 04/20/2021] [Indexed: 10/21/2022]
Abstract
To evaluate magnetic resonance (MR) T1 mapping for quantifying brain manganese (Mn) deposition in type C hepatic encephalopathy (CHE) rats and to investigate the mechanism of magnesium sulfate (MgSO4) therapy. Thirty Sprague-Dawley rats were randomly assigned into normal control group (NC, n = 6) and CHE groups (n = 24). Thioacetamide (TAA) was used for modeling CHE rats. CHE groups were further divided into 4 subgroups: TAA group, MgSO4 low dose (Mg-L) group, MgSO4 high dose (Mg-H) group and deionized water (DW) group (n = 6 for each group). TAA, Mg-L, Mg-H and DW groups were received intraperitoneal injections of 250 mg TAA/kg, twice a week for 8 weeks. Mg-L and Mg-H groups were orally received MgSO4 of 124 and 248 mg/kg daily, respectively, for another 8 weeks (without TAA). MR T1 mapping was performed in NC, TAA, Mg-L, Mg-H and DW groups at various time points. T1 value and Mn content in basal ganglia, hippocampus, cerebral cortex and cerebellum were evaluated. Morris water maze (MWM) and narrow beat test (NBT) were utilized to evaluate rats' learning, memory and motor ability. Contents of interleukin-6 (IL-6), tumor necrosis factor-a (TNF-a) and calcium-binding adaptor 1 protein (Iba1) were evaluated. Reduced T1 values in basal ganglia, hippocampus and cerebral cortex (P < 0.01, P < 0.05 and P < 0.05, respectively); increased Mn content in basal ganglia, hippocampus and cerebral cortex (all P < 0.05); reduced times of head contacting with region of interest (ROI), reduced times of entrance into the target quadrant (both P < 0.05); increased NBT total time (P < 0.05); increased brain contents of IL-6 (P < 0.001), TNF-α (P < 0.01) and over-expression of Iba1 were found in TAA group compared to NC group. After treated by MgSO4, increased T1 value and reduced Mn content in basal ganglia, hippocampus and cerebral cortex (all P < 0.01); increased times of head contacting with ROI, increased times of entrance into the target quadrant (both P < 0.05); reduced NBT total time (P < 0.01); reduced brain content of IL-6, TNF-α (both P < 0.05) and reduced expression of Iba1 were found. T1 values were negatively correlated with Mn contents in basal ganglia (r = - 0.834, P < 0.01), hippocampus (r = - 0.739, P < 0.05), cortex (r = - 0.801, P < 0.05) and cerebellum (r = - 0.788, P < 0.05). T1 mapping could quantify brain Mn deposition in CHE rats. MgSO4 could improve cognition and motor ability of CHE rats by reducing brain Mn deposition, alleviating neurological inflammation and achieve the effective therapy for CHE. Mn may participate in the pathogenesis of CHE through neuroinflammation.
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Mendes NF, Mariotti FFN, de Andrade JS, de Barros Viana M, Céspedes IC, Nagaoka MR, Le Sueur-Maluf L. Lactulose decreases neuronal activation and attenuates motor behavioral deficits in hyperammonemic rats. Metab Brain Dis 2017; 32:2073-2083. [PMID: 28875419 DOI: 10.1007/s11011-017-0098-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 08/16/2017] [Indexed: 12/14/2022]
Abstract
Lactulose is a nonabsorbable disaccharide commonly used in clinical practice to treat hepatic encephalopathy. However, its effects on neuropsychiatric disorders and motor behavior have not been fully elucidated. Male Wistar rats were bile-duct ligated, and 3 weeks after surgery, treated with lactulose administrated by gavage (1.43 or 3.57 g/kg), once a day for seven days. Plasma levels of ammonia, aspartate aminotransferase, total bilirubin, and creatinine were quantified and histopathological analysis of the livers was performed. Locomotor activity measurements were performed in an open field. The expression of water channel aquaporin-4 was investigated and the analysis of Fos protein immunoreactivity was used to evaluate the pattern of neural activation in brain areas related to motor behavior. Bile-duct ligated rats showed hyperammonemia, loss of liver integrity and function, impaired locomotor activity, reduced aquaporin-4 protein expression, and neuronal hyperactivity. Lactulose treatment was able to reduce ammonia plasma levels, despite not having an effect on biochemical parameters of liver function, such as aspartate aminotransferase activity and total bilirubin levels, or on the cirrhotic hepatic architecture. Lactulose was also able to reduce the locomotor activity impairments and to mitigate or reverse most changes in neuronal activation. Lactulose had no effect on reduced aquaporin-4 protein expression. Our findings confirm the effectiveness of lactulose in reducing hyperammonemia and neuronal hyperactivity in brain areas related to motor behavior, reinforcing the importance of its clinical use in the treatment of the symptoms of cirrhosis-associated encephalopathy.
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Affiliation(s)
- Natália Ferreira Mendes
- Departmento de Biociências, Universidade Federal de São Paulo, UNIFESP, 133/136 - Vila Mathias, Santos/SP, 11015-020, Brazil
- Laboratório de Sinalização Celular, Universidade Estadual de Campinas, UNICAMP, Campinas/SP, 13083-864, Brazil
| | - Flora França Nogueira Mariotti
- Departmento de Biociências, Universidade Federal de São Paulo, UNIFESP, 133/136 - Vila Mathias, Santos/SP, 11015-020, Brazil
| | - José Simões de Andrade
- Departmento de Biociências, Universidade Federal de São Paulo, UNIFESP, 133/136 - Vila Mathias, Santos/SP, 11015-020, Brazil
| | - Milena de Barros Viana
- Departmento de Biociências, Universidade Federal de São Paulo, UNIFESP, 133/136 - Vila Mathias, Santos/SP, 11015-020, Brazil
| | - Isabel Cristina Céspedes
- Departmento de Biociências, Universidade Federal de São Paulo, UNIFESP, 133/136 - Vila Mathias, Santos/SP, 11015-020, Brazil
- Departamento de Morfologia e Genética, Universidade Federal de São Paulo, UNIFESP, 11015-020, São Paulo/SP, 04023-900, Brazil
| | - Márcia Regina Nagaoka
- Departmento de Biociências, Universidade Federal de São Paulo, UNIFESP, 133/136 - Vila Mathias, Santos/SP, 11015-020, Brazil
| | - Luciana Le Sueur-Maluf
- Departmento de Biociências, Universidade Federal de São Paulo, UNIFESP, 133/136 - Vila Mathias, Santos/SP, 11015-020, Brazil.
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Oral administration of trace element magnesium significantly improving the cognition and locomotion in hepatic encephalopathy rats. Sci Rep 2017; 7:1817. [PMID: 28500320 PMCID: PMC5431966 DOI: 10.1038/s41598-017-02101-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 04/19/2017] [Indexed: 12/13/2022] Open
Abstract
The therapeutic effects of iron, zinc and magnesium trace elements, as well as rifaximin were investigated and compared in HE rats. In this study, HE rats were treated with either ferrous sulfate (HE-Fe, 30 mg/kg/day), zinc sulfate (HE-Zn, 30 mg/kg/day), magnesium sulfate (HE-Mg, 50 mg/kg/day) or rifaximin (HE-Rf, 50 mg/kg/day), which was mixed with water and administered orally for 61 days. The Morris water maze (MWM) and open-field tests were used to evaluate cognitive and locomotor function. The blood ammonia levels before and after administration of the glutamine challenge test, manganese concentration and glutamine synthetase (GS) activity were measured. Significantly longer MWM escape latencies, less locomotor activity, higher blood ammonia levels, higher brain manganese concentrations and higher GS activity were observed in HE rats. However, HE-Mg and HE-Rf rats had significantly shorter MWM escape latencies, increased locomotor activity, lower blood ammonia, lower brain manganese concentrations and lower GS activity. Partial improvements were observed in HE-Fe and HE-Zn rats. The results indicated that oral administration of magnesium can significantly improve the cognitive and locomotor functions in HE rats by reducing the brain manganese concentration and regulating GS activity.
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Li Y, Mei LH, Qiang JW, Ji CX, Ju S. Reduction of manganese intake improves neuropsychological manifestations in rats with minimal hepatic encephalopathy. Neuroscience 2017; 347:148-155. [DOI: 10.1016/j.neuroscience.2017.02.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 02/02/2017] [Accepted: 02/02/2017] [Indexed: 01/06/2023]
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Schroeter A, Wen S, Mölders A, Erlenhardt N, Stein V, Klöcker N. Depletion of the AMPAR reserve pool impairs synaptic plasticity in a model of hepatic encephalopathy. Mol Cell Neurosci 2015; 68:331-9. [DOI: 10.1016/j.mcn.2015.09.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 07/22/2015] [Accepted: 09/06/2015] [Indexed: 02/07/2023] Open
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Arias N, Méndez M, Arias J. Differential contribution of the hippocampus in two different demanding tasks at early stages of hepatic encephalopathy. Neuroscience 2015; 284:1-10. [DOI: 10.1016/j.neuroscience.2014.08.060] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 07/30/2014] [Accepted: 08/22/2014] [Indexed: 12/12/2022]
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Arias N, Fidalgo C, Felipo V, Arias JL. The effects of hyperammonemia in learning and brain metabolic activity. Metab Brain Dis 2014; 29:113-20. [PMID: 24415107 DOI: 10.1007/s11011-013-9477-0] [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: 10/10/2013] [Accepted: 12/23/2013] [Indexed: 12/22/2022]
Abstract
Ammonia is thought to be central in the development of hepatic encephalopathy. However, the specific relation of ammonia with brain energy depletions and learning has not been studied. Our work attempts to reproduce an increase in rat cerebral ammonia level, study the hyperamonemic animals' performance of two learning tasks, an allocentric (ALLO) and a cue guided (CG) task, and elucidate the contribution of hyperammonemia to the differential energy requirements of the brain limbic system regions involved in these tasks. To assess these goals, four groups of animals were used: a control (CHA) CG group (n = 10), a CHA ALLO group (n = 9), a hyperammonemia (HA) CG group (n = 7), and HA ALLO group (n = 8). Oxidative metabolism of the target brain regions were assessed by histochemical labelling of cytochrome oxidase (C.O.). The behavioural results revealed that the hyperammonemic rats were not able to reach the behavioural criterion in either of the two tasks, in contrast to the CHA groups. The metabolic brain consumption revealed increased C.O. activity in the anterodorsal thalamus when comparing the HA ALLO group with the CHA ALLO group. Significant differences between animals trained in the CG task were observed in the prelimbic, infralimbic, parietal, entorhinal and perirhinal cortices, the anterolateral and anteromedial striatum, and the basolateral and central amygdala. Our findings may provide fresh insights to reveal how the differential damage to the brain limbic structures involved in these tasks differs according to the degree of task difficulty.
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Affiliation(s)
- Natalia Arias
- Laboratory of Neuroscience, Departamento de Psicología, Universidad de Oviedo, Plaza Feijoo s/n 33003, Oviedo, Spain,
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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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Mapping metabolic brain activity in three models of hepatic encephalopathy. Int J Hypertens 2013; 2013:390872. [PMID: 23573412 PMCID: PMC3612461 DOI: 10.1155/2013/390872] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Accepted: 02/19/2013] [Indexed: 11/17/2022] Open
Abstract
Cirrhosis is a common disease in Western countries. Liver failure, hyperammonemia, and portal hypertension are the main factors that contribute to human cirrhosis that frequently leads to a neuropsychiatric disorder known as hepatic encephalopathy (HE). In this study, we examined the differential contribution of these leading factors to the oxidative metabolism of diverse brain limbic system regions frequently involved in memory process by histochemical labelling of cytochrome oxidase (COx). We have analyzed cortical structures such as the infralimbic and prelimbic cotices, subcortical structures such as hippocampus and ventral striatum, at thalamic level like the anterodorsal, anteroventral, and mediodorsal thalamus, and, finally, the hypothalamus, where the mammillary nuclei (medial and lateral) were measured. The severest alteration is found in the model that mimics intoxication by ammonia, followed by the thioacetamide-treated group and the portal hypertension group. No changes were found at the mammillary bodies for any of the experimental groups.
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Perazzo JC, Tallis S, Delfante A, Souto PA, Lemberg A, Eizayaga FX, Romay S. Hepatic encephalopathy: An approach to its multiple pathophysiological features. World J Hepatol 2012; 4:50-65. [PMID: 22489256 PMCID: PMC3321490 DOI: 10.4254/wjh.v4.i3.50] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2011] [Revised: 11/19/2011] [Accepted: 02/24/2012] [Indexed: 02/06/2023] Open
Abstract
Hepatic encephalopathy (HE) is a neuropsychiatric complex syndrome, ranging from subtle behavioral abnormalities to deep coma and death. Hepatic encephalopathy emerges as the major complication of acute or chronic liver failure. Multiplicity of factors are involved in its pathophysiology, such as central and neuromuscular neurotransmission disorder, alterations in sleep patterns and cognition, changes in energy metabolism leading to cell injury, an oxidative/nitrosative state and a neuroinflammatory condition. Moreover, in acute HE, a condition of imminent threat of death is present due to a deleterious astrocyte swelling. In chronic HE, changes in calcium signaling, mitochondrial membrane potential and long term potential expression, N-methyl-D-aspartate-cGMP and peripheral benzodiazepine receptors alterations, and changes in the mRNA and protein expression and redistribution in the cerebral blood flow can be observed. The main molecule indicated as responsible for all these changes in HE is ammonia. There is no doubt that ammonia, a neurotoxic molecule, triggers or at least facilitates most of these changes. Ammonia plasma levels are increased two- to three-fold in patients with mild to moderate cirrhotic HE and up to ten-fold in patients with acute liver failure. Hepatic and inter-organ trafficking of ammonia and its metabolite, glutamine (GLN), lead to hyperammonemic conditions. Removal of hepatic ammonia is a differentiated work that includes the hepatocyte, through the urea cycle, converting ammonia into GLN via glutamine synthetase. Under pathological conditions, such as liver damage or liver blood by-pass, the ammonia plasma level starts to rise and the risk of HE developing is high. Knowledge of the pathophysiology of HE is rapidly expanding and identification of focally localized triggers has led the development of new possibilities for HE to be considered. This editorial will focus on issues where, to the best of our knowledge, more research is needed in order to clarify, at least partially, controversial topics.
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Affiliation(s)
- Juan Carlos Perazzo
- Juan Carlos Perazzo, Silvina Tallis, Amalia Delfante, Pablo Andrés Souto, Abraham Lemberg, Francisco Xavier Eizayaga, Salvador Romay, Laboratory of Portal Hypertension and Hepatic Encephalopathy, Pathophysiology, School of Pharmacy and Biochemistry, University of Buenos Aires, Junin 950, CP 1113, Buenos Aires, Argentina
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