RESUMEN
Hepatic encephalopathy (HE) is a neurological complication arising from acute liver failure with poor prognosis and high mortality; the underlying cellular mechanisms are still wanting. We previously found that neuronal death caused by mitochondrial dysfunction in rostral ventrolateral medulla (RVLM), which leads to baroreflex dysregulation, is related to high fatality in an animal model of HE. Lipocalin-2 (Lcn2) is a secreted glycoprotein mainly released by astrocytes in the brain. We noted the presence of Lcn2 receptor (Lcn2R) in RVLM neurons and a parallel increase of Lcn2 gene in astrocytes purified from RVLM during experimental HE. Therefore, our guiding hypothesis is that Lcn2 secreted by reactive astrocytes in RVLM may underpin high fatality during HE by eliciting bioenergetic failure-induced neuronal death in this neural substrate. In this study, we first established the role of astrocyte-secreted Lcn2 in a liver toxin model of HE induced by azoxymethane (100 µg/g, ip) in C57BL/6 mice, followed by mechanistic studies in primary astrocyte and neuron cultures prepared from postnatal day 1 mouse pups. In animal study, immunoneutralization of Lcn2 reduced apoptotic cell death in RVLM, reversed defunct baroreflex-mediated vasomotor tone and prolonged survival during experimental HE. In our primary cell culture experiments, Lcn2 produced by cultured astrocytes and released into the astrocyte-conditioned medium significantly reduced cell viability of cultured neurons. Recombinant Lcn2 protein reduced cell viability, mitochondrial ATP (mitoATP) production, and pyruvate dehydrogenase (PDH) activity but enhanced the expression of pyruvate dehydrogenase kinase (PDK) 1, PDK3 and phospho-PDHA1 (inactive PDH) through MAPK/ERK pathway in cultured neurons, with all cellular actions reversed by Lcn2R knockdown. Our results suggest that astrocyte-secreted Lcn2 upregulates PDKs through MAPK/ERK pathway, which leads to reduced PDH activity and mitoATP production; the reinforced neuronal death in RVLM is causally related to baroreflex dysregulation that underlies high fatality associated with HE.
Asunto(s)
Astrocitos , Muerte Celular , Modelos Animales de Enfermedad , Encefalopatía Hepática , Lipocalina 2 , Ratones Endogámicos C57BL , Neuronas , Animales , Astrocitos/metabolismo , Astrocitos/patología , Lipocalina 2/metabolismo , Encefalopatía Hepática/metabolismo , Encefalopatía Hepática/patología , Neuronas/metabolismo , Neuronas/patología , Ratones , Muerte Celular/fisiología , Masculino , Metabolismo Energético/fisiología , Metabolismo Energético/efectos de los fármacos , Células CultivadasRESUMEN
BACKGROUND: Hepatic encephalopathy (HE) is closely associated with inflammatory responses. However, as a crucial regulator of the immune and inflammatory responses, the role of leucine-rich repeat kinase 2 (LRRK2) in the pathogenesis of HE remains unraveled. Herein, we investigated this issue in thioacetamide (TAA)-induced HE following acute liver failure (ALF). METHODS: TAA-induced HE mouse models of LRRK2 wild type (WT), LRRK2 G2019S mutation (Lrrk2G2019S) and LRRK2 knockout (Lrrk2-/-) were established. A battery of neurobehavioral experiments was conducted. The biochemical indexes and pro-inflammatory cytokines were detected. The prefrontal cortex (PFC), striatum (STR), hippocampus (HIP), and liver were examined by pathology and electron microscopy. The changes of autophagy-lysosomal pathway and activity of critical Rab GTPases were analyzed. RESULTS: The Lrrk2-/--HE model reported a significantly lower survival rate than the other two models (24% vs. 48%, respectively, p < 0.05), with no difference found between the WT-HE and Lrrk2G2019S-HE groups. Compared with the other groups, after the TAA injection, the Lrrk2-/- group displayed a significant increase in ammonium and pro-inflammatory cytokines, aggravated hepatic inflammation/necrosis, decreased autophagy, and abnormal phosphorylation of lysosomal Rab10. All three models reported microglial activation, neuronal loss, disordered vesicle transmission, and damaged myelin structure. The Lrrk2-/--HE mice presented no severer neuronal injury than the other genotypes. CONCLUSIONS: LRRK2 deficiency may exacerbate TAA-induced ALF and HE in mice, in which inflammatory response is evident in the brain and aggravated in the liver. These novel findings indicate a need of sufficient clinical awareness of the adverse effects of LRRK2 inhibitors on the liver.
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Encefalopatía Hepática , Proteína 2 Quinasa Serina-Treonina Rica en Repeticiones de Leucina , Fallo Hepático Agudo , Ratones Noqueados , Tioacetamida , Animales , Ratones , Encefalopatía Hepática/patología , Encefalopatía Hepática/genética , Proteína 2 Quinasa Serina-Treonina Rica en Repeticiones de Leucina/genética , Proteína 2 Quinasa Serina-Treonina Rica en Repeticiones de Leucina/metabolismo , Fallo Hepático Agudo/inducido químicamente , Fallo Hepático Agudo/patología , Fallo Hepático Agudo/genética , Ratones Endogámicos C57BL , Tioacetamida/toxicidadRESUMEN
Hepatic encephalopathy (HE) is defined as decline in neurological function during chronic liver disease (CLD). Alcohol is a major etiological factor in the pathogenesis of fibrosis/cirrhosis and has also been documented to directly impact the brain. However, the role of alcohol in the development of HE in CLD remains unclear. Here, we investigated the impact of excessive alcohol administration on neurological deterioration in rats with CLD. Starting day 7 post-BDL surgery, rats were administered alcohol twice daily (51% v/v ethanol, 3 g/kg, via gavage) for 4 weeks. Motor coordination was assessed weekly using rotarod and anxiety-like behavior was evaluated with open field and elevated plus maze at 5 weeks. Upon sacrifice, brains were collected for western blot and immunohistochemical analyses to investigate neuronal integrity and oxidative stress status. Alcohol worsened motor coordination performance and increased anxiety-like behavior in BDL rats. Impairments were associated with decreased neuronal markers of NeuN and SMI311, increased apoptotic markers of cleaved/pro-caspase-3 and Bax/Bcl2, increased necroptosis markers of pRIP3 and pMLKL, decreased total antioxidant capacity (TAC), and increased 4-hydroxynonenal (4-HNE)modified proteins in the cerebellum of BDL-alcohol rats when compared to respective controls. Immunofluorescence confirmed the colocalization of cleaved caspase-3 and pMLKL in the granular neurons of the cerebellum of BDL-alcohol rats. Excessive alcohol consumption exacerbates HE which leads to associated apoptotic and necroptotic neuronal loss in the cerebellum of BDL-alcohol rats. Additionally, higher levels of 4-HNE and decreased TAC in the cerebellum of BDL-alcohol rats suggest oxidative stress is the triggering factor of apoptotic and necroptotic neuronal loss/injury.
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Etanol , Encefalopatía Hepática , Neuronas , Estrés Oxidativo , Animales , Masculino , Encefalopatía Hepática/patología , Encefalopatía Hepática/inducido químicamente , Encefalopatía Hepática/metabolismo , Etanol/toxicidad , Etanol/efectos adversos , Ratas , Neuronas/patología , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Estrés Oxidativo/efectos de los fármacos , Estrés Oxidativo/fisiología , Muerte Celular/efectos de los fármacos , Ratas Sprague-Dawley , Apoptosis/efectos de los fármacos , Ansiedad/etiologíaRESUMEN
AIM: To explore the use of quantitative susceptibility mapping (QSM) in assessing changes in brain iron deposits and their association with cognitive function in patients with minimal hepatic encephalopathy (MHE). MATERIALS AND METHODS: The study cohort comprised 27 cases with hepatitis B-associated cirrhosis with MHE (MHE group), 25 with hepatitis B-associated cirrhosis without MHE (NMHE group), and 25 healthy controls (HC group). Iron deposits in the bilateral frontal white matter, caudate nucleus (CN), putamen, globus pallidus, thalamus, red nucleus, substantia nigra (SN), hippocampus, and dentate nucleus were measured by QSM. The associations between iron deposition with the time taken to complete number connection tests A (NCT-A) and the score on digital-symbol test (DST) were analysed. RESULTS: Susceptibility values differed significantly in the bilateral CN, left thalamus, right SN, and left hippocampus in the MHE group compared with the other groups and were positively associated with the times taken to complete the NCT-A in the bilateral CN, left thalamus, and right SN and negatively associated with DST scores in the bilateral CN, left TH, and left HP. CONCLUSION: Reduced cognitive function in MHE patients was significantly associated with abnormally increased iron deposition in certain brain areas. The quantification of brain iron deposition by QSM may thus be an objective and accurate means of evaluating MHE.
Asunto(s)
Encefalopatía Hepática , Hepatitis B , Humanos , Encefalopatía Hepática/diagnóstico por imagen , Encefalopatía Hepática/patología , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Imagen por Resonancia Magnética , Mapeo Encefálico , Cirrosis Hepática/patología , HierroRESUMEN
Hepatic encephalopathy (HE) is one of the most debilitating cerebral complications of liver cirrhosis. The one-year survival of patients with liver cirrhosis and severe encephalopathy is less than 50%. Recent studies have indicated that neuroinflammation is a new player in the pathogenesis of HE, which seems to be involved in the development of cognitive impairment. In this study, we demonstrated neurobehavioral and neuropathological consequences of liver cirrhosis and tested the therapeutic potential of the tumor necrosis factor-α (TNF-α) inhibitor, etanercept. Sixty male adult Wistar albino rats (120-190 g) were allocated into four groups, where groups I and IV served as controls. Thioacetamide (TAA; 300 mg/kg) was intraperitoneally injected twice a week for five months to induce liver cirrhosis in group II (n = 20). Both TAA and etanercept (2 mg/kg) were administered to group III (n = 20). At the end of the experiment, spatial learning was assessed using Morris water maze. TNF-α was detected in both serum and hippocampus. The excised brains were also immunohistochemically stained with glial fibrillary acidic protein (GFAP) to estimate both the number and integrity of hippocampal astrocytes. Ultrastructural changes in the hippocampus were characterized by transmission electron microscopy. The results showed that blocking TNF-α by etanercept was accompanied by a lower TNF-α expression and a higher number of GFAP-positive astrocytes in the hippocampus. Etanercept intervention alleviated the neuronal and glial degenerative changes and impeded the deterioration of spatial learning ability. In conclusion, TNF-α is strongly involved in the development of liver cirrhosis and the associated encephalopathy. TNF-α blockers may be a promising approach for management of hepatic cirrhosis and its cerebral complications.
Asunto(s)
Encefalopatías , Encefalopatía Hepática , Ratas , Animales , Humanos , Masculino , Factor de Necrosis Tumoral alfa/metabolismo , Etanercept/farmacología , Etanercept/metabolismo , Aprendizaje Espacial , Modelos Animales de Enfermedad , Cirrosis Hepática/inducido químicamente , Cirrosis Hepática/tratamiento farmacológico , Ratas Wistar , Hipocampo/metabolismo , Encefalopatías/metabolismo , Encefalopatías/patología , Encefalopatía Hepática/tratamiento farmacológico , Encefalopatía Hepática/metabolismo , Encefalopatía Hepática/patología , Tioacetamida/toxicidadRESUMEN
BACKGROUND: Hepatic encephalopathy (HE) is a consequence of chronic or acute liver diseases. This study evaluates the combined effect of gallic acid (GA), and metformin (Met) on the liver and brain damage associated with HE. METHODS: Acute HE was induced by a single dose of thioacetamide (TAA) (300 mg/kg) as an I.P. injection. Treated groups received GA group (100 mg/kg/day, p.o), Met (200 mg/kg/day, p.o), or their combination for 25 consecutive days before TAA injection. RESULTS: The administration of TAA induced various biochemical and histopathological alterations. In contrast, treatment with GA either alone or combined with Met resulted in improved liver functions by the significant reduction in serum ALT, AST, and ALP activities, and ammonia levels. Inflammatory mediators; TNF-α, IL-6, and NFkß levels were decreased by these treatments as well as apoptotic cascade via down-regulation of FAS and caspase-3 (CASP-3) expression in hepatic tissues. Furthermore, GA and Met either alone or combined protected the liver and brain tissues from damage by increased glutathione concentration while decreasing malondialdehyde. In addition, it was accompanied by the improvement of the brain neurotransmitter profile via the restoration of norepinephrine, dopamine, and serotonin levels. Based on our data, this is the first study to report a novel combined hepatoprotective and cognitive enhancing effect of GA and Met against TAA-induced acute liver and brain injury. CONCLUSION: GA and Met combination resulted in a prominent improvement in HE complications, relative to monotherapy. Both agents potentiated the antioxidant, anti-inflammatory, and anti-apoptotic effects of each other.
Asunto(s)
Encefalopatía Hepática , Metformina , Ratas , Animales , Encefalopatía Hepática/tratamiento farmacológico , Encefalopatía Hepática/inducido químicamente , Encefalopatía Hepática/patología , FN-kappa B/metabolismo , Tioacetamida/efectos adversos , Ácido Gálico/farmacología , Caspasa 3/metabolismo , Metformina/farmacología , Ratas Wistar , Inflamación/tratamiento farmacológico , Inflamación/metabolismo , Estrés Oxidativo , Transducción de Señal , ApoptosisRESUMEN
OBJECTIVES: To evaluate the dynamic evolution process of overall brain health in liver transplantation (LT) recipients, we employed a deep learning-based neuroanatomic biomarker to measure longitudinal changes of brain structural patterns before and 1, 3, and 6 months after surgery. METHODS: Because of the ability to capture patterns across all voxels from a brain scan, the brain age prediction method was adopted. We constructed a 3D-CNN model through T1-weighted MRI of 3609 healthy individuals from 8 public datasets and further applied it to a local dataset of 60 LT recipients and 134 controls. The predicted age difference (PAD) was calculated to estimate brain changes before and after LT, and the network occlusion sensitivity analysis was used to determine the importance of each network in age prediction. RESULTS: The PAD of patients with cirrhosis increased markedly at baseline (+ 5.74 years) and continued to increase within one month after LT (+ 9.18 years). After that, the brain age began to decrease gradually, but it was still higher than the chronological age. The PAD values of the OHE subgroup were higher than those of the no-OHE, and the discrepancy was more obvious at 1-month post-LT. High-level cognition-related networks were more important in predicting the brain age of patients with cirrhosis at baseline, while the importance of primary sensory networks increased temporarily within 6-month post-LT. CONCLUSIONS: The brain structural patterns of LT recipients showed inverted U-shaped dynamic change in the early stage after transplantation, and the change in primary sensory networks may be the main contributor. KEY POINTS: ⢠The recipients' brain structural pattern showed an inverted U-shaped dynamic change after LT. ⢠The patients' brain aging aggravated within 1 month after surgery, and the subset of patients with a history of OHE was particularly affected. ⢠The change of primary sensory networks is the main contributor to the change in brain structural patterns.
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Encefalopatía Hepática , Trasplante de Hígado , Humanos , Estudios Longitudinales , Encefalopatía Hepática/patología , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Cirrosis Hepática/patología , FibrosisRESUMEN
Patients with liver cirrhosis show hyperammonemia and peripheral inflammation and may show hepatic encephalopathy with cognitive impairment, reproduced by rats with chronic hyperammonemia. Peripheral inflammation induces neuroinflammation in hippocampus of hyperammonemic rats, altering neurotransmission and leading to cognitive impairment. Extracellular vesicles (EVs) may transmit pathological effects from the periphery to the brain. We hypothesized that EVs from peripheral blood would contribute to cognitive alterations in hyperammonemic rats. The aims were to assess whether EVs from plasma of hyperammonemic rats (HA-EVs) induce cognitive impairment and to identify the underlying mechanisms. Injection of HA-EVs impaired learning and memory, induced microglia and astrocytes activation and increased TNFα and IL-1ß. Ex vivo incubation of hippocampal slices from control rats with HA-EVs reproduced these alterations. HA-EVs increased membrane expression of TNFR1, reduced membrane expression of TGFßR2 and Smad7 and IκBα levels and increased IκBα phosphorylation. This led to increased activation of NF-κB and IL-1ß production, altering membrane expression of NR2B, GluA1 and GluA2 subunits, which would be responsible for cognitive impairment. All these effects of HA-EVs were prevented by blocking TNFα, indicating that they were mediated by enhanced activation of TNFR1 by TNFα. We show that these mechanisms are very different from those leading to motor incoordination, which is due to altered GABAergic neurotransmission in cerebellum. This demonstrates that peripheral EVs play a key role in the transmission of peripheral alterations to the brain in hyperammonemia and hepatic encephalopathy, inducing neuroinflammation and altering neurotransmission in hippocampus, which in turn is responsible for the cognitive deficits.
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Vesículas Extracelulares , Encefalopatía Hepática , Hiperamonemia , Ratas , Animales , Ratas Wistar , Factor de Necrosis Tumoral alfa/metabolismo , Receptores Tipo I de Factores de Necrosis Tumoral/metabolismo , Receptores Tipo I de Factores de Necrosis Tumoral/farmacología , Enfermedades Neuroinflamatorias , Inhibidor NF-kappaB alfa/metabolismo , Inhibidor NF-kappaB alfa/farmacología , Encefalopatía Hepática/metabolismo , Encefalopatía Hepática/patología , Hiperamonemia/metabolismo , Hiperamonemia/patología , Inflamación/metabolismo , Cognición , Vesículas Extracelulares/metabolismo , Hipocampo/metabolismoRESUMEN
The delayed consequences of the influence of hepatic encephalopathy (HE) on the metabolism of animals have not been studied enough. We have previously shown that the development of acute HE under the influence of the thioacetamide (TAA) toxin is accompanied by pathological changes in the liver, an imbalance in CoA and acetyl CoA, as well as a number of metabolites of the TCA cycle. This paper discusses the change in the balance of amino acids (AAs) and related metabolites, as well as the activity of glutamine transaminase (GTK) and ω-amidase enzymes in the vital organs of animals 6 days after a single exposure to TAA. The balance of the main AAs in blood plasma, liver, kidney, and brain samples of control (n = 3) and TAA-induced groups (n = 13) of rats that received the toxin at doses of 200, 400, and 600 mg/kg was considered. Despite the apparent physiological recovery of the rats at the time of sampling, a residual imbalance in AA and associated enzymes persisted. The data obtained give an idea of the metabolic trends in the body of rats after their physiological recovery from TAA exposure and may be useful for prognostic purposes when choosing the necessary therapeutic agents.
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Aminoácidos , Encefalopatía Hepática , Animales , Ratas , Aminoácidos/metabolismo , Encefalopatía Hepática/inducido químicamente , Encefalopatía Hepática/patología , Hígado/metabolismo , Hígado/patología , Ratas Wistar , Tioacetamida/efectos adversosRESUMEN
PURPOSE: To demonstrate that patients with pre-cirrhotic bridging fibrosis (Meta-analysis of Histological Data in Viral Hepatitis, METAVIR stage F3) and clinically significant portal hypertension (CSPH, Hepatic Venous Pressure Gradient ≥10 mmHg) experience a higher rate of clinical decompensation than patients without CSPH. MATERIALS AND METHODS: 128 consecutive patients with pathology proven bridging fibrosis without cirrhosis between 2012 and 2019 were reviewed. Inclusion criteria were patients with HVPG measurement obtained during the same outpatient transjugular liver biopsy and clinical follow up of at least two years. Primary endpoint included rate of overall complication related to portal hypertension including evidence of either ascites, presence of varices on imaging or endoscopy, or evidence of hepatic encephalopathy. RESULTS: Among 128 patients with bridging fibrosis (67 females and 61 males; average age 56 years), 42 (33%) and 86 (67%) were with and without CSPH (HVPG ≥10 mmHg). Median follow-up time was 4 years. Rate of overall complication (either ascites, varices or hepatic encephalopathy) in patients with and without CSPH was 36/42 (86%) and 39/86 (45%) (p < .001) respectively. Rate of developing ascites, varices and hepatic encephalopathy in patients with and without CSPH was 21/42 (50%) vs 26/86 (30%) (p = .034), 32/42 (76%) vs 26/86 (30%) (p ≤ .001) and 18/42 (43%) vs 12/86 (14%) (p = .001) respectively. CONCLUSION: Patients with pre-cirrhotic bridging fibrosis and CSPH were associated with higher rates of developing ascites, varices and hepatic encephalopathy. Measuring HVPG during transjugular liver biopsy provides additional prognostic value in anticipating clinical decompensation in patients with pre-cirrhotic bridging fibrosis.
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Encefalopatía Hepática , Hipertensión Portal , Várices , Masculino , Femenino , Humanos , Persona de Mediana Edad , Encefalopatía Hepática/complicaciones , Encefalopatía Hepática/patología , Ascitis/complicaciones , Ascitis/patología , Relevancia Clínica , Hígado/patología , Cirrosis Hepática/complicaciones , Hipertensión Portal/etiología , Presión Portal , Biopsia/efectos adversosRESUMEN
BACKGROUND: The objectives of this study were to evaluate incidence and to identify the risk factors of occurrence and the predictive factors of symptomatic forms of nodular regenerative hyperplasia (NRH) after liver transplantation (LT). METHODS: To identify risk factors of NRH following LT, we included 1648 patients transplanted from 2004 to 2018 and compared the patients developing NRH after LT to those who did not. To identify predictive factors of symptomatic NRH, we selected 115 biopsies displaying NRH and compared symptomatic to asymptomatic forms. Symptomatic NRH was defined as the presence of ascites, esophageal varices, hepatic encephalopathy, portal thrombosis, retransplantation, or death related to NRH. RESULTS: The incidence of NRH following LT was 5.1%. In multivariate analysis, the independent factor of developing NRH after LT was the donor's age (odds ratio [OR] = 1.02; confidence interval, 1.01-1.03; P = 0.02). Symptomatic forms occurred in 29 (25.2%) patients: 19 (16.5%) patients presented with ascites, 13 (11.3%) with esophageal varices, 4 (3.5%) with hepatic encephalopathy, and 8 (7%) with portal thrombosis. The median period before the onset of symptoms was 8.4 (1.5-11.3) y after LT. The spleen size at diagnosis/before LT ratio (OR = 12.5; 114.17-1.37; P = 0.0252) and thrombectomy during transplantation (OR = 11.17; 1.48-84.11; P = 0.0192) were associated with symptomatic NRH in multivariate analysis. CONCLUSIONS: NRH following LT is frequent (5.1%) and leads to symptomatic portal hypertension in 25.2% of patients. Using older grafts increases the risk of developing NRH after LT. Clinicians should screen for signs of portal hypertension, particularly in measuring spleen size.
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Várices Esofágicas y Gástricas , Encefalopatía Hepática , Hipertensión Portal , Trasplante de Hígado , Trombosis , Humanos , Trasplante de Hígado/efectos adversos , Hígado/patología , Hiperplasia/complicaciones , Hiperplasia/patología , Várices Esofágicas y Gástricas/complicaciones , Várices Esofágicas y Gástricas/patología , Ascitis/epidemiología , Ascitis/etiología , Encefalopatía Hepática/complicaciones , Encefalopatía Hepática/patología , Incidencia , Hipertensión Portal/diagnóstico , Hipertensión Portal/epidemiología , Hipertensión Portal/etiología , Trombosis/patologíaRESUMEN
Minimal hepatic encephalopathy (MHE) is diagnosed using PHES battery, but other tests are more sensitive, and a simple tool for early MHE detection is required. Assessment of saccadic eye movements is useful for early detection of cognitive alterations in different pathologies. We characterized the alterations in saccadic eye movements in MHE patients, its relationship with cognitive alterations and its utility for MHE diagnosis. One-hundred and eighteen cirrhotic patients (86 without and 32 with MHE) and 35 controls performed PHES and Stroop test and an eye movements test battery by OSCANN system: visual saccades, antisaccades, memory-guided saccades, fixation test and smooth pursuit. We analyzed 177 parameters of eye movements, assessed their diagnostic capacity for MHE, and correlated with cognitive alterations. MHE patients showed alterations in 56 of the 177 variables of eye movements compared to NMHE patients. MHE patients showed longer latencies and worse performance in most eye movements tests, which correlated with mental processing speed and attention impairments. The best correlations found were for antisaccades and memory-guided saccades, and some parameters in these tests could be useful for discriminating MHE and NMHE patients. Eye movements analysis could be a new, rapid, reliable, objective, and reproducible tool for early diagnose MHE.
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Encefalopatía Hepática , Estudios de Casos y Controles , Movimientos Oculares , Encefalopatía Hepática/patología , Humanos , Cirrosis Hepática/psicología , PsicometríaRESUMEN
Growing evidence suggests an essential role of neuroinflammation in behavioral abnormalities associated with hepatic encephalopathy (HE). Here, we report the involvement of autotaxin-lysophosphatidic acid (LPA) signaling in HE's pathogenesis. We demonstrate that the autotaxin (ATX) inhibitor PF-8380 attenuates neuroinflammation and improves neurological dysfunction in the mouse model of HE. In the thioacetamide (TAA)-induced model of HE, we found a twofold increase in the levels of ammonia in the brain and in plasma along with a significant change in HE-related behavioral parameters. Mice with HE show an increased brain weight, increased levels of tumor necrosis factor-α (TNF-α), IL-1ß (interleukin-1ß), interleukin-6 (IL-6), and LPA 18:0 in the cerebral cortex and hippocampus, and increased levels of LPA 18:0 in plasma. Treatment with the autotaxin inhibitor (ATXi) did not affect liver injury, as we observed no change in liver function markers including aspartate aminotransferase (AST), alanine aminotransferase (ALT), and total bilirubin (TBIL) and no change in ammonia levels in the brain and plasma. However, ATXi treatment significantly ameliorated the neuroinflammation, reduced the levels of LPA 18:0 in the cerebral cortex and hippocampus in the brain and plasma, and reduced brain edema and the levels of IL1ß, IL-6, and TNF-α. The neurobehavioral symptoms for HE such as the cognitive and motor function deficit and overall clinical grading score were significantly improved in ATXi-treated mice. Mouse astrocytes and microglia stimulated with NH4CL with or without ATXi showed significant attenuation of oxidative stress and the neuroinflammatory effect of NH4CL in ATXi-treated cells.
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Encefalopatías , Encefalopatía Hepática , Alanina Transaminasa/uso terapéutico , Amoníaco/efectos adversos , Animales , Aspartato Aminotransferasas/uso terapéutico , Bilirrubina/efectos adversos , Encefalopatía Hepática/inducido químicamente , Encefalopatía Hepática/tratamiento farmacológico , Encefalopatía Hepática/patología , Interleucina-1beta , Interleucina-6 , Lisofosfolípidos , Ratones , Enfermedades Neuroinflamatorias , Tioacetamida/efectos adversos , Factor de Necrosis Tumoral alfaRESUMEN
Hyperammonemia plays a main role in the neurological impairment in cirrhotic patients with hepatic encephalopathy. Rats with chronic hyperammonemia reproduce the motor incoordination of patients with minimal hepatic encephalopathy, which is due to enhanced GABAergic neurotransmission in cerebellum as a consequence of neuroinflammation. Extracellular vesicles (EVs) could play a key role in the transmission of peripheral alterations to the brain to induce neuroinflammation and neurological impairment in hyperammonemia and hepatic encephalopathy. EVs from plasma of hyperammonemic rats (HA-EVs) injected to normal rats induce neuroinflammation and motor incoordination, but the underlying mechanisms remain unclear. The aim of this work was to advance in the understanding of these mechanisms. To do this we used an ex vivo system. Cerebellar slices from normal rats were treated ex vivo with HA-EVs. The aims were: 1) assess if HA-EVs induce microglia and astrocytes activation and neuroinflammation in cerebellar slices of normal rats, 2) assess if this is associated with activation of the TNFR1-NF-kB-glutaminase-GAT3 pathway, 3) assess if the TNFR1-CCL2-BDNF-TrkB pathway is activated by HA-EVs and 4) assess if the increased TNFα levels in HA-EVs are responsible for the above effects and if they are prevented by blocking the action of TNFα. Our results show that ex vivo treatment of cerebellar slices from control rats with extracellular vesicles from hyperammonemic rats induce glial activation, neuroinflammation and enhance GABAergic neurotransmission, reproducing the effects induced by hyperammonemia in vivo. Moreover, we identify in detail key underlying mechanisms. HA-EVs induce the activation of both the TNFR1-CCL2-BDNF-TrkB-KCC2 pathway and the TNFR1-NF-kB-glutaminase-GAT3 pathway. Activation of these pathways enhances GABAergic neurotransmission in cerebellum, which is responsible for the induction of motor incoordination by HA-EVs. The data also show that the increased levels of TNFα in HA-EVs are responsible for the above effects and that the activation of both pathways is prevented by blocking the action of TNFα. This opens new therapeutic options to improve motor incoordination in hyperammonemia and also in cirrhotic patients with hepatic encephalopathy and likely in other pathologies in which altered cargo of extracellular vesicles contribute to the propagation of the pathology.
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Vesículas Extracelulares , Encefalopatía Hepática , Hiperamonemia , Animales , Ataxia/complicaciones , Ataxia/metabolismo , Ataxia/patología , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Cerebelo/metabolismo , Vesículas Extracelulares/metabolismo , Glutaminasa/metabolismo , Encefalopatía Hepática/complicaciones , Encefalopatía Hepática/metabolismo , Encefalopatía Hepática/patología , Hiperamonemia/complicaciones , Hiperamonemia/metabolismo , Hiperamonemia/patología , Cirrosis Hepática/patología , FN-kappa B/metabolismo , Enfermedades Neuroinflamatorias , Ratas , Ratas Wistar , Receptores Tipo I de Factores de Necrosis Tumoral/metabolismo , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
The toxicity of acetaminophen (N-acetyl-para-aminophenol (APAP)) is the most frequent cause of drug-induced liver damage. Galium aparine L. (GA) is traditionally used to treat jaundice. We aimed to investigate the hepatoprotective potential of GA in the APAP-induced hepatic encephalopathy (HE) rat model. Qualitative phytochemical characterization of GA was performed by LC/Q-TOF/MS analysis. Wistar rats were pretreated with GA (250 and 500 mg/kg b.wt. per oral) for five days. On the 6th day, the rats were exposed to APAP (1500 mg/kg b.wt. oral gavage) and behavioral tests (open field and passive avoidance tests) were applied on the 7th and 8th days. The animals were killed, and biochemical and histopathological parameters were assessed in blood and hepatic specimens. GA pretreated rats exhibited a significant reduction in APAP-induced liver damage, evidenced by the reduction in liver necrosis and alanine aminotransferase (ALT), aspartate aminotransferase (AST), and bilirubin (BIL). GA demonstrated an anxiolytic effect, as seen in the acquisition trial and grooming behavior. The short-term memory performances of animals were not changed in all groups, suggesting that APAP intoxication did not affect hippocampal function. These results show that GA extract markedly exerts hepatoprotective activity, while its effect on hepatic encephalopathy was limited.
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Ansiolíticos , Enfermedad Hepática Inducida por Sustancias y Drogas , Galium , Encefalopatía Hepática , Acetaminofén/toxicidad , Alanina Transaminasa , Animales , Ansiolíticos/farmacología , Aspartato Aminotransferasas , Bilirrubina , Enfermedad Hepática Inducida por Sustancias y Drogas/tratamiento farmacológico , Enfermedad Hepática Inducida por Sustancias y Drogas/patología , Enfermedad Hepática Inducida por Sustancias y Drogas/prevención & control , Encefalopatía Hepática/patología , Hígado , Extractos Vegetales/farmacología , Ratas , Ratas WistarRESUMEN
BACKGROUND AND AIMS: Minimal hepatic encephalopathy (MHE) is a common neuropsychiatric complication in patients with cirrhosis. Alterations in monoamine neurotransmitters have been associated with the pathogenesis of MHE. We investigated the levels of hippocampal noradrenergic neurotransmitter in a rat model of thioacetamide-induced chronic liver failure-related MHE, and their role in cognitive impairment. MATERIALS: 18 male Sprague-Dawley (SD) rats were equally divided in MHE and control groups. A rat model of MHE was established by intraperitoneal injection of thioacetamide (TAA) for 12 weeks. Cognitive function was assessed using the Morris water maze (MWM) test and locomotor activity and exploratory behavior assessed with open field test. The concentration of hippocampal noradrenaline (NE) was detected by ELISA, and the magnetic susceptibility value in the hippocampus was detected by quantitative susceptibility mapping. Hippocampal iron content was quantified by Prussian blue staining. RESULTS: MHE rats performed significantly poorer than their control counterparts in the MWM test, as seen by decreased number of platform crossings and time in the target quadrant, and increased path length to reach the target zone (P < 0.05 for all parameters). In the open field test, the MHE group exhibited lower locomotor activity and exploratory behavior than the control group (P < 0.05 for all parameters). We detected pronounced iron staining in the hippocampus of MHE rats, whereas no iron-stained particles were found in control rats. We observed an imbalance of inflammatory (increased pro- and decreased anti-) cytokines in the hippocampus of MHE rats. Further analysis of the data showed that the level of hippocampal noradrenaline in MHE rats was significantly lower than that of control rats (P < 0.05). We observed a correlation between the level of inflammatory cytokine and noradrenaline land susceptibility value in the rat hippocampus of the MHE group. CONCLUSION: Our results suggest that MHE associated with TAA-induced chronic liver failure is associated with alterations in noradrenergic neurotransmission. We propose that iron imbalance in the brain might lead to reduction in the levels of noradrenaline, and cognitive impairment.
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Disfunción Cognitiva , Enfermedad Hepática en Estado Terminal , Encefalopatía Hepática , Animales , Encéfalo/metabolismo , Disfunción Cognitiva/patología , Citocinas/metabolismo , Enfermedad Hepática en Estado Terminal/complicaciones , Enfermedad Hepática en Estado Terminal/patología , Encefalopatía Hepática/complicaciones , Encefalopatía Hepática/patología , Cirrosis Hepática/complicaciones , Cirrosis Hepática/patología , Masculino , Norepinefrina , Ratas , Ratas Sprague-Dawley , Tioacetamida/toxicidadRESUMEN
Background: Hyperammonemia can result in various neuropathologies, including sleep disturbance, memory loss, and motor dysfunction in hepatic encephalopathy. Long noncoding RNA (lncRNA) as a group of noncoding RNA longer than 200 nucleotides is emerging as a promising therapeutic target to treat diverse diseases. Although lncRNAs have been linked to the pathogenesis of various diseases, their function in hepatic encephalopathy has not yet been elucidated. Research Design and Methods. To identify the roles of lncRNAs in hepatic encephalopathy brain, we used a bile duct ligation (BDL) mouse model and examined the alteration of neuronal cell death markers and neuronal structure-related proteins in BDL mouse cortex tissue. Furthermore, analysis of the transcriptome of BDL mouse brain cortex tissues revealed several lncRNAs critical to the apoptosis and neuronal structural changes associated with hepatic encephalopathy. Results: We confirmed the roles of the lncRNAs, ZFAS1, and GAS5 as strong candidate lncRNAs to regulate neuropathologies in hepatic encephalopathy. Our data revealed the roles of lncRNAs, ZFAS1, and GAS5, on neuronal cell death and neural structure in hyperammonemia in in vivo and in vitro conditions. Conclusion: Thus, we suggest that the modulation of these lncRNAs may be beneficial for the treatment of hepatic encephalopathy.
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Encefalopatía Hepática , Hiperamonemia , ARN Largo no Codificante , Animales , Conductos Biliares , Encefalopatía Hepática/genética , Encefalopatía Hepática/patología , Hiperamonemia/complicaciones , Hiperamonemia/genética , Ratones , Neuronas/metabolismo , ARN Largo no Codificante/genética , ARN Largo no Codificante/metabolismoRESUMEN
Hepatic encephalopathy describes an array of neurological complications that arise due to liver insufficiency. The pathogenesis of hepatic encephalopathy shares a longstanding association with hyperammonemia and inflammation, and recently, aberrant bile acid signaling has been implicated in the development of key features of hepatic encephalopathy. These key features include neuronal dysfunction, neuroinflammation and blood-brain barrier permeability. This review summarizes the findings of recent studies demonstrating a role for bile acids in the pathogenesis of hepatic encephalopathy via one of three main bile acid receptors and speculates on the possible downstream consequences of aberrant bile acid signaling.
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Ácidos y Sales Biliares/metabolismo , Encefalopatía Hepática/metabolismo , Receptores Citoplasmáticos y Nucleares/metabolismo , Animales , Encefalopatía Hepática/patología , HumanosRESUMEN
The occurrence and progress of minimal hepatic encephalopathy (MHE) is closely related to the inflammatory response; however, inflammation contributes to behavioral abnormalities and sleep disorders. Dexmedetomidine has anti-inflammatory effects against various diseases. Whether dexmedetomidine improves MHE and the underlying mechanism is yet unclear. The present study aimed to explore the effects of dexmedetomidine on sleep structure, neurobehavior, and brain morphology of MHE rats and investigate its underlying mechanism. A rat MHE model was established by intraperitoneal injection of thioacetamide (TAA). Dexmedetomidine or yohimbine was administered intraperitoneally to investigate the role of α2 adrenoreceptor in the protection conferred by dexmedetomidine. The 24-h sleep, neurobehavioral changes, the liver function, blood ammonia and morphological changes of the liver and brain were assessed. Also, the microglia, astrocytes, neurons, the expression of pro-inflammatory factors (IL-1ß, TNF-α, IL-18), and NLRP3 inflammasomes were detected. The results showed that marked sleep disorders, cognitive impairment, anxiety, abnormal liver function and pathological damage of liver and brain were detected in the MHE rats. The microglia in the prefrontal cortex was highly activated along with the increased expression of pro-inflammatory factors and NLRP3 inflammasomes. Interestingly, dexmedetomidine improved above indicators, however, yohimbine significantly abolished the protection of dexmedetomidine. These findings showed that dexmedetomidine restored the changes in the sleep disorders and neurobehavior in rats and reduced brain damage. The mechanism might be partially related to the activation of α2 adrenergic receptors, reduction of neuroinflammatory response, and inhibition of the activation of microglia and NLRP3/Caspase1 signaling pathway.
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Agonistas de Receptores Adrenérgicos alfa 2/uso terapéutico , Antiinflamatorios/uso terapéutico , Ansiedad/tratamiento farmacológico , Disfunción Cognitiva/tratamiento farmacológico , Dexmedetomidina/uso terapéutico , Encefalopatía Hepática/tratamiento farmacológico , Trastornos del Sueño-Vigilia/tratamiento farmacológico , Agonistas de Receptores Adrenérgicos alfa 2/farmacología , Amoníaco/sangre , Animales , Ansiedad/inmunología , Ansiedad/patología , Conducta Animal/efectos de los fármacos , Disfunción Cognitiva/inmunología , Disfunción Cognitiva/patología , Citocinas/inmunología , Dexmedetomidina/farmacología , Encefalopatía Hepática/inmunología , Encefalopatía Hepática/patología , Inflamasomas/inmunología , Hígado/efectos de los fármacos , Hígado/patología , Masculino , Microglía/efectos de los fármacos , Microglía/patología , Proteína con Dominio Pirina 3 de la Familia NLR/inmunología , Corteza Prefrontal/efectos de los fármacos , Corteza Prefrontal/inmunología , Corteza Prefrontal/patología , Ratas Sprague-Dawley , Trastornos del Sueño-Vigilia/inmunología , Trastornos del Sueño-Vigilia/patologíaRESUMEN
The episodes of cerebral dysfunction, known as encephalopathy, are usually coincident with liver failure. The primary metabolic marker of liver diseases is the increase in blood ammonium, which promotes neuronal damage. In the present project, we used an experimental model of hepatic encephalopathy in male rats by portacaval anastomosis (PCA) surgery. Sham rats had a false operation. After 13 weeks of surgery, the most distinctive finding was vacuolar/spongiform neurodegeneration exclusively in the molecular layer of the cerebellum. This cerebellar damage was further characterized by metabolic, histopathological, and behavioral approaches. The results were as follows: (a) Cellular alterations, namely loss of Purkinje cells, morphological changes, such as swelling of astrocytes and Bergmann glia, and activation of microglia; (b) Cytotoxic edema, shown by an increase in aquaporin-4 and N-acetylaspartate and a reduction in taurine and choline-derivate osmolytes; (c) Metabolic adjustments, noted by the elevation of circulating ammonium, enhanced presence of glutamine synthetase, and increase in glutamine and creatine/phosphocreatine; (d) Inflammasome activation, detected by the elevation of the marker NLRP3 and microglial activation; (e) Locomotor deficits in PCA rats as assessed by the Rotarod and open field tests. These results lead us to suggest that metabolic disturbances associated with PCA can generate the cerebellar damage that is similar to morphophysiological modifications observed in amyloidogenic disorders. In conclusion, we have characterized a distinctive cerebellar multi-disruption accompanied by high levels of ammonium and associated with spongiform neurodegeneration in a model of hepatic hypofunctioning.