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Archie SR, Al Shoyaib A, Cucullo L. Blood-Brain Barrier Dysfunction in CNS Disorders and Putative Therapeutic Targets: An Overview. Pharmaceutics 2021; 13:pharmaceutics13111779. [PMID: 34834200 PMCID: PMC8622070 DOI: 10.3390/pharmaceutics13111779] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 10/15/2021] [Accepted: 10/20/2021] [Indexed: 01/22/2023] Open
Abstract
The blood-brain barrier (BBB) is a fundamental component of the central nervous system (CNS). Its functional and structural integrity is vital to maintain the homeostasis of the brain microenvironment by controlling the passage of substances and regulating the trafficking of immune cells between the blood and the brain. The BBB is primarily composed of highly specialized microvascular endothelial cells. These cells’ special features and physiological properties are acquired and maintained through the concerted effort of hemodynamic and cellular cues from the surrounding environment. This complex multicellular system, comprising endothelial cells, astrocytes, pericytes, and neurons, is known as the neurovascular unit (NVU). The BBB strictly controls the transport of nutrients and metabolites into brain parenchyma through a tightly regulated transport system while limiting the access of potentially harmful substances via efflux transcytosis and metabolic mechanisms. Not surprisingly, a disruption of the BBB has been associated with the onset and/or progression of major neurological disorders. Although the association between disease and BBB disruption is clear, its nature is not always evident, specifically with regard to whether an impaired BBB function results from the pathological condition or whether the BBB damage is the primary pathogenic factor prodromal to the onset of the disease. In either case, repairing the barrier could be a viable option for treating and/or reducing the effects of CNS disorders. In this review, we describe the fundamental structure and function of the BBB in both healthy and altered/diseased conditions. Additionally, we provide an overview of the potential therapeutic targets that could be leveraged to restore the integrity of the BBB concomitant to the treatment of these brain disorders.
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Affiliation(s)
- Sabrina Rahman Archie
- Department of Pharmaceutical Sciences, Texas Tech University Health Sciences Center, Amarillo, TX 79106, USA; (S.R.A.); (A.A.S.)
| | - Abdullah Al Shoyaib
- Department of Pharmaceutical Sciences, Texas Tech University Health Sciences Center, Amarillo, TX 79106, USA; (S.R.A.); (A.A.S.)
| | - Luca Cucullo
- Department of Foundational Medical Studies, Oakland University William Beaumont School of Medicine, Rochester, MI 48309, USA
- Correspondence: ; Tel.: +1-248-370-3884; Fax: +1-248-370-4060
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Hajipour S, Sarkaki A, Dianat M, Rashno M, Khorsandi LS, Farbood Y. The effects of thymoquinone on memory impairment and inflammation in rats with hepatic encephalopathy induced by thioacetamide. Metab Brain Dis 2021; 36:991-1002. [PMID: 33620578 DOI: 10.1007/s11011-021-00688-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 02/08/2021] [Indexed: 12/11/2022]
Abstract
Hepatic encephalopathy (HE) is a prevalent complication of the central nervous system (CNS) that is caused by acute or chronic liver failure. This study was designed to evaluate the effects of thymoquinone (TQ) on thioacetamide (TAA)-induced HE in rats, and determine the consequential behavioral, biochemical, and histological changes. HE was induced in male Wistar rats by intraperitoneal (i.p.) injection of 200 mg/kg TAA once every 48 h for 14 consecutive days. Control groups received the normal saline containing 5 % DMSO. Thymoquinone (5, 10, and 20 mg/kg) was administered for ten consecutive days intraperitoneally (i.p.) after HE induction and it was continued until the end of the tests. Then, the passive avoidance memory, extracellular single unit, BBB permeability, and brain water content were evaluated. Moreover, hippocampal tissues were used for evaluation of oxidative stress index, inflammatory biomarkers, and histological parameters following HE. As result of the treatment, TQ improved passive avoidance memory, increased the average number of simultaneous firing of spikes/bins, improved the integrity of BBB, and decreased brain water content in the animal model of HE. Furthermore, the results indicated that treatment with TQ decreased the levels of inflammatory cytokines (TNF-α and IL-1β) but increased the levels of glutathione (GSH) and anti-inflammatory cytokine (IL-10) of the surviving cells in the hippocampal tissues. This study demonstrates that TQ may have beneficial therapeutic effects on cognitive, oxidative stress, neuroinflammatory, and histological complications of HE in rat.
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Affiliation(s)
- Somayeh Hajipour
- Persian Gulf Physiology Research Center, Medical Basic Sciences Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Alireza Sarkaki
- Persian Gulf Physiology Research Center, Medical Basic Sciences Research Institute, 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
| | - Mahin Dianat
- Persian Gulf Physiology Research Center, Medical Basic Sciences Research Institute, 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, Cellular & Molecular Research Center, Medical Basic Sciences Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Laaya Sadat Khorsandi
- Department of Anatomical Sciences, Cellular & Molecular Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Yaghoob Farbood
- Persian Gulf Physiology Research Center, Medical Basic Sciences Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
- Department of Physiology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
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Dhanda S, Sandhir R. Blood-Brain Barrier Permeability Is Exacerbated in Experimental Model of Hepatic Encephalopathy via MMP-9 Activation and Downregulation of Tight Junction Proteins. Mol Neurobiol 2017; 55:3642-3659. [PMID: 28523565 DOI: 10.1007/s12035-017-0521-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 04/06/2017] [Indexed: 12/27/2022]
Abstract
The present study was designed to investigate the mechanisms involved in blood-brain barrier (BBB) permeability in bile duct ligation (BDL) model of chronic hepatic encephalopathy (HE). Four weeks after BDL surgery, a significant increase was observed in serum bilirubin levels. Masson trichrome staining revealed severe hepatic fibrosis in the BDL rats. 99mTc-mebrofenin retention was increased in the liver of BDL rats suggesting impaired hepatobiliary transport. An increase in permeability to sodium fluorescein, Evans blue, and fluorescein isothiocyanate (FITC)-dextran along with increase in water and electrolyte content was observed in brain regions of BDL rats suggesting disrupted BBB. Increased brain water content can be attributed to increase in aquaporin-4 mRNA and protein expression in BDL rats. Matrix metalloproteinase-9 (MMP-9) mRNA and protein expression was increased in brain regions of BDL rats. Additionally, mRNA and protein expression of tissue inhibitor of matrix metalloproteinases (TIMPs) was also increased in different regions of brain. A significant decrease in mRNA expression and protein levels of tight junction proteins, viz., occludin, claudin-5, and zona occluden-1 (ZO-1) was observed in different brain regions of BDL rats. VCAM-1 mRNA and protein expression was also found to be significantly upregulated in different brain regions of BDL animals. The findings from the study suggest that increased BBB permeability in HE involves activation of MMP-9 and loss of tight junction proteins.
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Affiliation(s)
- Saurabh Dhanda
- Department of Biochemistry, Basic Medical Science Block-II, Sector-25, Panjab University, Chandigarh, 160014, India
| | - Rajat Sandhir
- Department of Biochemistry, Basic Medical Science Block-II, Sector-25, Panjab University, Chandigarh, 160014, India.
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Establishment of a Novel Simplified Surgical Model of Acute Liver Failure in the Cynomolgus Monkey. BIOMED RESEARCH INTERNATIONAL 2016; 2016:3518989. [PMID: 28097130 PMCID: PMC5209601 DOI: 10.1155/2016/3518989] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 11/19/2016] [Accepted: 11/28/2016] [Indexed: 12/19/2022]
Abstract
Models using large animals that are suitable for studying artificial liver support system (ALSS) are urgently needed. Presently available acute liver failure (ALF) models mainly involve pigs or dogs. Establishment of current surgical ALF models (hepatectomy/devascularization) requires either very good surgical skills or multistep processes—even multiple stages of surgery. Therefore, it is necessary to develop a simplified surgical method. Here we report a novel simplified surgical ALF model using cynomolgus monkeys. Six monkeys underwent portal-right renal venous shunt combined with common bile duct ligation and transection (PRRS + CBDLT). Postoperatively, the monkeys had progressively increased listlessness, loss of appetite, and obvious jaundice. Blood biochemistry levels (Amm, ALT, AST, TBiL, DBiL, ALP, LDH, CK, and Cr) and prothrombin time (PT) were significantly increased (all P < 0.01) and albumin (ALB) was markedly reduced (P < 0.01) compared with baseline values. Histological examination of liver specimens on postoperative day 10 revealed cholestasis and inflammation. PRRS + CBDLT produced ALF that closely correlated with clinical situations. Compared with other surgical or drug ALF models, ours was simplified and animals were hemodynamically stable. This model could provide a good platform for further research on ALSS, especially regarding their detoxification functions.
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Palenzuela L, Oria M, Romero-Giménez J, Garcia-Lezana T, Chavarria L, Cordoba J. Gene expression profiling of brain cortex microvessels may support brain vasodilation in acute liver failure rat models. Metab Brain Dis 2016; 31:1405-1417. [PMID: 27406245 DOI: 10.1007/s11011-016-9863-5] [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: 02/26/2016] [Accepted: 06/19/2016] [Indexed: 12/13/2022]
Abstract
Development of brain edema in acute liver failure can increase intracranial pressure, which is a severe complication of the disease. However, brain edema is neither entirely cytotoxic nor vasogenic and the specific action of the brain microvasculature is still unknown. We aimed to analyze gene expression of brain cortex microvessels in two rat models of acute liver failure. In order to identify global gene expression changes we performed a broad transcriptomic approach in isolated brain cortex microvessels from portacaval shunted rats after hepatic artery ligation (HAL), hepatectomy (HEP), or sham by array hybridization and confirmed changes in selected genes by RT-PCR. We found 157 and 270 up-regulated genes and 143 and 149 down-regulated genes in HAL and HEP rats respectively. Western blot and immunohistochemical assays were performed in cortex and ELISA assays to quantify prostaglandin E metabolites were performed in blood of the sagittal superior sinus. We Identified clusters of differentially expressed genes involving inflammatory response, transporters-channels, and homeostasis. Up-regulated genes at the transcriptional level were associated with vasodilation (prostaglandin-E synthetase, prostaglandin-E receptor, adrenomedullin, bradykinin receptor, adenosine transporter), oxidative stress (hemoxygenase, superoxide dismutase), energy metabolism (lactate transporter) and inflammation (haptoglobin). The only down-regulated tight junction protein was occludin but slightly. Prostaglandins levels were increased in cerebral blood with progression of liver failure. In conclusion, in acute liver failure, up-regulation of several genes at the level of microvessels might suggest an involvement of energy metabolism accompanied by cerebral vasodilation in the cerebral edema at early stages.
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Affiliation(s)
- Lluis Palenzuela
- Servei de Medicina Interna-Hepatologia, Valld'Hebron Institut de Recerca (VH-IR), Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain
- Departament de Medicina, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Marc Oria
- Servei de Medicina Interna-Hepatologia, Valld'Hebron Institut de Recerca (VH-IR), Barcelona, Spain.
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain.
- Departament de Medicina, Universitat Autònoma de Barcelona, Barcelona, Spain.
- Center for Fetal, Cellular and Mollecular Therapy, Division of Pediatric General and Thoracic Surgery, Cincinnati Children's Hospital Medical Center (CCHMC), Cincinnati, OH, USA.
| | - Jordi Romero-Giménez
- Servei de Medicina Interna-Hepatologia, Valld'Hebron Institut de Recerca (VH-IR), Barcelona, Spain
- Departament de Medicina, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Teresa Garcia-Lezana
- Servei de Medicina Interna-Hepatologia, Valld'Hebron Institut de Recerca (VH-IR), Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain
- Departament de Medicina, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Laia Chavarria
- Servei de Medicina Interna-Hepatologia, Valld'Hebron Institut de Recerca (VH-IR), Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain
- Departament de Medicina, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Juan Cordoba
- Servei de Medicina Interna-Hepatologia, Valld'Hebron Institut de Recerca (VH-IR), Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain
- Departament de Medicina, Universitat Autònoma de Barcelona, Barcelona, Spain
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Bernal W, Murphy N, Brown S, Whitehouse T, Bjerring PN, Hauerberg J, Frederiksen HJ, Auzinger G, Wendon J, Larsen FS. A multicentre randomized controlled trial of moderate hypothermia to prevent intracranial hypertension in acute liver failure. J Hepatol 2016; 65:273-9. [PMID: 26980000 DOI: 10.1016/j.jhep.2016.03.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 03/03/2016] [Accepted: 03/07/2016] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Animal models and human case series of acute liver failure (ALF) suggest moderate hypothermia (MH) to have protective effects against cerebral oedema (CO) development and intracranial hypertension (ICH). However, the optimum temperature for patient management is unknown. In a prospective randomized controlled trial we investigated if maintenance of MH prevented development of ICH in ALF patients at high risk of the complication. METHODS Patients with ALF, high-grade encephalopathy and intracranial pressure (ICP) monitoring in specialist intensive care units were randomized by sealed envelope to targeted temperature management (TTM) groups of 34°C (MH) or 36°C (control) for a period of 72h. Investigators were not blinded to group assignment. The primary outcome was a sustained elevation in ICP >25mmHg, with secondary outcomes the occurrence of predefined serious adverse effects, magnitude of ICP elevations and cerebral and all-cause hospital mortality (with or without transplantation). RESULTS Forty-six patients were randomized, of whom forty-three were studied. There was no significant difference between the TTM groups in the primary outcome during the study period (35% vs. 27%, p=0.56), for the MH (n=17) or control (n=26) groups respectively, relative risk 1.31 (95% CI 0.53-3.2). Groups had similar incidence of adverse events and overall mortality (41% vs. 46%, p=0.75). CONCLUSIONS In patients with ALF at high risk of ICH, MH at 33-34°C did not confer a benefit above management at 36°C in prevention of ICH or in overall survival. This study did not confirm advantage of its prophylactic use. (ISRCTN registration number 74268282; no funding.) LAY SUMMARY Studies in animals with acute liver failure (ALF) have suggested that cooling (hypothermia) could prevent or limit the development of brain swelling, a dangerous complication of the condition. There is limited data on its effects in humans. In a randomized controlled trial in severely ill patients with ALF we compared the effects of different temperatures and found no benefit on improving survival or preventing brain swelling by controlling temperature at 33-34°C against 36°C.
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Affiliation(s)
- William Bernal
- Liver Intensive Care Unit, Institute of Liver Studies, Kings College Hospital, Denmark Hill, London SE5 9RS, United Kingdom.
| | - Nicholas Murphy
- Department of Anaesthesia and Critical Care, University Hospital Birmingham, Birmingham B15 2GW, United Kingdom
| | - Sarah Brown
- Liver Intensive Care Unit, Institute of Liver Studies, Kings College Hospital, Denmark Hill, London SE5 9RS, United Kingdom
| | - Tony Whitehouse
- Department of Anaesthesia and Critical Care, University Hospital Birmingham, Birmingham B15 2GW, United Kingdom
| | - Peter Nissen Bjerring
- Department of Hepatology, Rigshospitalet, University Hospital Copenhagen, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - John Hauerberg
- Department of Neurosurgery, Rigshospitalet, University Hospital Copenhagen, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Hans J Frederiksen
- Department of Anaesthesia, Rigshospitalet, University Hospital Copenhagen, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Georg Auzinger
- Liver Intensive Care Unit, Institute of Liver Studies, Kings College Hospital, Denmark Hill, London SE5 9RS, United Kingdom
| | - Julia Wendon
- Liver Intensive Care Unit, Institute of Liver Studies, Kings College Hospital, Denmark Hill, London SE5 9RS, United Kingdom
| | - Fin Stolze Larsen
- Department of Hepatology, Rigshospitalet, University Hospital Copenhagen, Blegdamsvej 9, 2100 Copenhagen, Denmark
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Bosoi CR, Rose CF. Elevated cerebral lactate: Implications in the pathogenesis of hepatic encephalopathy. Metab Brain Dis 2014; 29:919-25. [PMID: 24916505 DOI: 10.1007/s11011-014-9573-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 05/28/2014] [Indexed: 01/31/2023]
Abstract
Hepatic encephalopathy (HE), a complex neuropsychiatric syndrome, is a frequent complication of liver failure/disease. Increased concentrations of lactate are commonly observed in HE patients, in the systemic circulation, but also in the brain. Traditionally, increased cerebral lactate is considered a marker of energy failure/impairment however alterations in lactate homeostasis may also lead to a rise in brain lactate and result in neuronal dysfunction. The latter may involve the development of brain edema. This review will target the significance of increased cerebral lactate in the pathogenesis of HE.
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Affiliation(s)
- Cristina R Bosoi
- Hepato-Neuro Laboratory, Centre Hospitalier de l'Université de Montréal (CRCHUM), 900, rue Saint-Denis - Tour Viger R08.422, Québec, H2X 0A9, Canada,
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Hori T, Uemoto S, Walden LB, Chen F, Baine AMT, Hata T, Kogure T, Nguyen JH. Matrix metalloproteinase-9 as a therapeutic target for the progression of fulminant liver failure with hepatic encephalopathy: A pilot study in mice. Hepatol Res 2014; 44:651-62. [PMID: 23672352 DOI: 10.1111/hepr.12161] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Revised: 05/08/2013] [Accepted: 05/09/2013] [Indexed: 12/13/2022]
Abstract
AIM If progressive liver injury and subsequent hepatic encephalopathy can be prohibited in fulminant liver failure (FLF), it would be ideal for intensive care of FLF and provide an expanded opportunity for liver transplantation (LT). We hypothesized that matrix metalloproteinase (MMP)-9 plays an important role in FLF progression, and investigated MMP-9 behaviors in a murine FLF model, especially at the coma stage. METHODS The murine FLF model with azoxymethane recapitulates FLF in humans. The detailed coma status was evaluated, on the assumption that LT is indicated at early, but not late, stage 3. To investigate whether MMP-9 deletion or reduction has beneficial effects, an MMP-9 inhibitor (GM6001) and transfection of tissue inhibitor of metalloproteinases (TIMP)-1 cDNA were used. Mice were divided into five groups: control; FLF; FLF with GM6001 pretreatment; FLF with TIMP-1 plasmid transfection 24 h before disease onset; and FLF with TIMP-1 plasmid transfection 48 h before disease onset. Neurological findings, including survival, were followed. Samples were obtained at early and late stage 3. Biochemical examinations and histopathological assessments were performed. The expression and function of MMP-9 and TIMP-1 were evaluated by western blotting and zymography. A brain permeability study was also performed. RESULTS MMP-9 was strongly increased in FLF. The MMP-9 inhibitions worked well, and prolonged the survival, interval to stage 3 and duration of early stage 3. MMP-9 inhibition improved the liver and subsequent brain injuries at early stage 3, with no remarkable improvements at late stage 3. CONCLUSION MMP-9 has therapeutic potential for FLF progression.
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Affiliation(s)
- Tomohide Hori
- Department of Neuroscience, Mayo Clinic in Florida; Division of Hepato-Biliary-Pancreatic and Transplant Surgery, Department of Surgery, Kyoto University Graduate School of Medicine, Kyoto
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Abstract
Systemic inflammation is common in liver failure and its acquisition is a predictor of hepatic encephalopathy severity. New studies provide convincing evidence for a role of neuroinflammation (inflammation of the brain per se) in liver failure; this evidence includes activation of microglia, together with increased synthesis in situ of the proinflammatory cytokines TNF, IL-1β and IL-6. Liver-brain signalling mechanisms in liver failure include: direct effects of systemic proinflammatory molecules, recruitment of monocytes after microglial activation, brain accumulation of ammonia, lactate and manganese, and altered permeability of the blood-brain barrier. Ammonia and cytokines might act synergistically. Existing strategies to reduce ammonia levels (including lactulose, rifaximin and probiotics) have the potential to dampen systemic inflammation, as does albumin dialysis, mild hypothermia and N-acetylcysteine, the latter two agents acting at both peripheral and central sites. Minocycline, an agent with potent central anti-inflammatory properties, reduces neuroinflammation, brain oedema and encephalopathy in liver failure, as does the anti-TNF agent etanercept.
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Kawaguchi T, Taniguchi E, Sata M. Effects of oral branched-chain amino acids on hepatic encephalopathy and outcome in patients with liver cirrhosis. Nutr Clin Pract 2013; 28:580-8. [PMID: 23945292 DOI: 10.1177/0884533613496432] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Branched-chain amino acids (BCAAs) constituting of valine, leucine, and isoleucine act as both substrates of proteins and as key regulators for various nutrient metabolisms. Patients with liver cirrhosis frequently lack sufficient BCAAs and therefore suffer from various metabolic disorders. Hepatic encephalopathy (HE) is a severe metabolic disorder with neurologic manifestations such as flapping tremors and coma in patients with liver cirrhosis. In addition, a mild form of HE known as minimal HE (MHE) is an important social issue because it occurs in up to 80% of patients with chronic liver disease and affects prognosis and activities of daily living, possibly resulting in falls and motor vehicle accidents. Although HE/MHE can be caused by various pathological conditions, including in an accumulation of mercaptans, short-chain fatty acids, and alterations in the gut flora, hyperammonemia has also been implicated in an important pathogenesis of HE/MHE. Besides urea cycle of liver, ammonia can be detoxified in the skeletal muscles by the amidation process for glutamine synthesis using BCAAs. Thus, BCAA supplementation may enhance detoxification of ammonia in skeletal muscle and may be a possible therapeutic strategy for HE/MHE. In this review, we summarize the clinical impacts of BCAA supplementation on HE/MHE and discuss possible mechanisms for a BCAA-induced improvement of HE/MHE. Furthermore, we present some modifications of oral BCAA therapy for improvement of efficacy in HE treatment. We also briefly describe pleiotropic benefits of BCAAs on life-threatening events and overall prognosis in patients with liver cirrhosis.
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Affiliation(s)
- Takumi Kawaguchi
- Takumi Kawaguchi, Division of Gastroenterology, Department of Medicine, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011, Japan.
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TIMP-1 attenuates blood-brain barrier permeability in mice with acute liver failure. J Cereb Blood Flow Metab 2013; 33:1041-9. [PMID: 23532086 PMCID: PMC3705430 DOI: 10.1038/jcbfm.2013.45] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 02/28/2013] [Accepted: 03/03/2013] [Indexed: 02/06/2023]
Abstract
Blood-brain barrier (BBB) dysfunction in acute liver failure (ALF) results in increased BBB permeability that often precludes the patients from obtaining a life-saving liver transplantation. It remains controversial whether matrix metalloproteinase-9 (MMP-9) from the injured liver contributes to the deregulation of BBB function in ALF. We selectively upregulated a physiologic inhibitor of MMP-9 (TIMP-1) with a single intracerebroventricular injection of TIMP-1 cDNA plasmids at 48 and 72 hours, or with pegylated-TIMP-1 protein. Acute liver failure was induced with tumor necrosis factor-α and D-(+)-galactosamine in mice. Permeability of BBB was assessed with sodium fluorescein (NaF) extravasation. We found a significant increase in TIMP-1 within the central nervous system (CNS) after the administration of TIMP-1 cDNA plasmids and that increased TIMP-1 within the CNS resulted in an attenuation of BBB permeability, a reduction in activation of epidermal growth factor receptor and p38 mitogen-activated protein kinase signals, and a restoration of the tight junction protein occludin in mice with experimental ALF. Pegylated TIMP-1 provided similar protection against BBB permeability in mice with ALF. Our results provided a proof of principle that MMP-9 contributes to the BBB dysfunction in ALF and suggests a potential therapeutic role of TIMP-1 in ALF.
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Bosoi CR, Rose CF. Brain edema in acute liver failure and chronic liver disease: similarities and differences. Neurochem Int 2013; 62:446-57. [PMID: 23376027 DOI: 10.1016/j.neuint.2013.01.015] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 01/11/2013] [Accepted: 01/16/2013] [Indexed: 12/12/2022]
Abstract
Hepatic encephalopathy (HE) is a complex neuropsychiatric syndrome that typically develops as a result of acute liver failure or chronic liver disease. Brain edema is a common feature associated with HE. In acute liver failure, brain edema contributes to an increase in intracranial pressure, which can fatally lead to brain stem herniation. In chronic liver disease, intracranial hypertension is rarely observed, even though brain edema may be present. This discrepancy in the development of intracranial hypertension in acute liver failure versus chronic liver disease suggests that brain edema plays a different role in relation to the onset of HE. Furthermore, the pathophysiological mechanisms involved in the development of brain edema in acute liver failure and chronic liver disease are dissimilar. This review explores the types of brain edema, the cells, and pathogenic factors involved in its development, while emphasizing the differences in acute liver failure versus chronic liver disease. The implications of brain edema developing as a neuropathological consequence of HE, or as a cause of HE, are also discussed.
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Affiliation(s)
- Cristina R Bosoi
- Neuroscience Research Unit, Hôpital Saint-Luc (CRCHUM), Université de Montréal, Québec, Canada
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13
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Pathogenesis of hepatic encephalopathy. Gastroenterol Res Pract 2012; 2012:642108. [PMID: 23316223 PMCID: PMC3534214 DOI: 10.1155/2012/642108] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2012] [Revised: 11/16/2012] [Accepted: 11/16/2012] [Indexed: 02/06/2023] Open
Abstract
Hepatic encephalopathy can be a serious complication of acute liver failure and chronic liver diseases, predominantly liver cirrhosis. Hyperammonemia plays the most important role in the pathogenesis of hepatic encephalopathy. The brain-blood barrier disturbances, changes in neurotransmission, neuroinflammation, oxidative stress, GABA-ergic or benzodiazepine pathway abnormalities, manganese neurotoxicity, brain energetic disturbances, and brain blood flow abnormalities are considered to be involved in the development of hepatic encephalopathy. The influence of small intestine bacterial overgrowth (SIBO) on the induction of minimal hepatic encephalopathy is recently emphasized. The aim of this paper is to present the current views on the pathogenesis of hepatic encephalopathy.
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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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15
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Vaquero J. Therapeutic hypothermia in the management of acute liver failure. Neurochem Int 2012; 60:723-35. [DOI: 10.1016/j.neuint.2011.09.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Revised: 09/13/2011] [Accepted: 09/13/2011] [Indexed: 02/07/2023]
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16
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Nguyen JH. Blood-brain barrier in acute liver failure. Neurochem Int 2011; 60:676-83. [PMID: 22100566 DOI: 10.1016/j.neuint.2011.10.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Revised: 10/20/2011] [Accepted: 10/26/2011] [Indexed: 12/16/2022]
Abstract
Brain edema remains a challenging obstacle in the management of acute liver failure (ALF). Cytotoxic mechanisms associated with brain edema have been well recognized, but evidence for vasogenic mechanisms in the pathogenesis of brain edema in ALF has been lacking. Recent reports have not only shown a role of matrix metalloproteinase-9 in the pathogenesis of brain edema in experimental ALF but have also found significant alterations in the tight junction elements including occludin and claudin-5, suggesting a vasogenic injury in the blood-brain barrier (BBB) integrity. This article reviews and explores the role of the paracellular tight junction proteins in the increased selective BBB permeability that leads to brain edema in ALF.
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Affiliation(s)
- Justin H Nguyen
- Division of Transplant Surgery, Department of Transplantation, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224, United States.
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17
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Toris GT, Bikis CN, Tsourouflis GS, Theocharis SE. Hepatic encephalopathy: an updated approach from pathogenesis to treatment. Med Sci Monit 2011; 17:RA53-63. [PMID: 21278704 PMCID: PMC3524698 DOI: 10.12659/msm.881387] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
One of the most serious complications of chronic or fulminant liver failure is hepatic encephalopathy (HE), associated most commonly with cirrhosis. In the presence of chronic liver disease, HE is a sign of decompensation, while in fulminant liver failure its development represents a worrying sign and usually indicates that transplantation will be required. Despite the significance of HE in the course of liver disease, the progress in development of new therapeutic options has been unremarkable over the last 20 years. An up-to-date review regarding HE, including both research and review articles. HE is a serious and progressive, but potentially reversible, disorder with a wide spectrum of neuropsychiatric abnormalities and motor disturbances that ranges from mild alteration of cognitive and motor function to coma and death. Although a clear pathogenesis is yet to be determined, elevated ammonia in serum and the central nervous system is the mainstay for pathogenesis and treatment of HE. Management includes early diagnosis and prompt treatment of precipitating factors. Clinical trials and extensive clinical experience have established the efficacy of diverse substances in HE treatment. Novel therapies with clinical promise include: L-ornithine L-aspartate, sodium benzoate, phenylacetate, AST-120, and the molecular adsorbent recirculating system. Eventually, liver transplantation is often the most successful long-term therapy for HE.
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Affiliation(s)
- Giannakis T Toris
- Department of Forensic Medicine and Toxicology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
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18
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Chen F, Hori T, Ohashi N, Baine AM, Eckman CB, Nguyen JH. Occludin is regulated by epidermal growth factor receptor activation in brain endothelial cells and brains of mice with acute liver failure. Hepatology 2011; 53:1294-305. [PMID: 21480332 PMCID: PMC3079316 DOI: 10.1002/hep.24161] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
UNLABELLED Mechanisms of brain edema in acute liver failure (ALF) are not completely understood. We recently demonstrated that matrix metalloproteinase 9 (MMP-9) induces significant alterations to occludin in brain endothelial cells in vitro and in brains of mice with experimental ALF (Hepatology 2009;50:1914). In this study we show that MMP-9-induced transactivation of epidermal growth factor receptor (EGFR) and p38 MAPK/NFκB (mitogen-activated protein kinase/nuclear factor-kappa B) signals participate in regulating brain endothelial occludin level. Mouse brain endothelial bEnd3 cells were exposed to MMP-9 or p38 MAPK up-regulation in the presence and absence of EGFR inhibitor, p38 MAPK inhibitor, NFκB inhibitor, and/or appropriate small interfering RNA. Reverse-transcription polymerase chain reaction (RT-PCR) and western blotting were used for messenger RNA and protein expression analyses. Immunohistochemical staining and confocal microscopy were used to demonstrate cellular EGFR activation. Intraperitoneal azoxymethane was use to induce ALF in mice. Brains of comatose ALF mice were processed for histological and biochemical analyses. When bEnd3 cells were exposed to MMP-9, EGFR was significantly transactivated, followed by p38 MAPK activation, I-kappa B alpha (IκBα) degradation, NFκB activation, and suppression of occludin synthesis and expression. Similar EGFR activation and p38 MAPK/NFκB activation were found in the brains of ALF mice, and these changes were attenuated with GM6001 treatment. CONCLUSION EGFR activation with p38 MAPK/NFκB signaling contributes to the regulation of tight junction integrity in ALF. EGFR activation may thus play an important role in vasogenic brain edema in ALF.
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Affiliation(s)
- Feng Chen
- Department of Neuroscience Mayo Clinic, Jacksonville, FL
| | - Tomohide Hori
- Department of Neuroscience Mayo Clinic, Jacksonville, FL
| | | | | | | | - Justin H. Nguyen
- Division of Transplant Surgery, Department of Transplantation, Mayo Clinic, Jacksonville, FL
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19
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Skowrońska M, Zielińska M, Albrecht J. Stimulation of natriuretic peptide receptor C attenuates accumulation of reactive oxygen species and nitric oxide synthesis in ammonia-treated astrocytes. J Neurochem 2010; 115:1068-76. [PMID: 20854429 DOI: 10.1111/j.1471-4159.2010.07008.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Oxidative and nitrosative stress contribute to ammonia-induced astrocytic dysfunction in hepatic encephalopathy. Treatment of cultured astrocytes with 5 mmol/L ammonium chloride ('ammonia') increased the production of reactive oxygen species (ROS), including the toxic NADPH oxidase reaction product, •O(2)(-). Atrial natriuretic peptide (ANP), natriuretic peptide C and a selective natriuretic peptide receptor (NPR)-C ligand, cANP((4-23),) each decreased the total ROS content both in control cells and cells treated with ammonia. However, attenuation of •O(2)(-) accumulation by ANP and cANP((4-23),) was observed in ammonia-treated cells only and the effect of cANP((4-23)) was decreased when the NADPH oxidase-regulatory protein G(iα-2) was blocked with a specific anti-G(iα-2) antibody. Although in contrast to ANP, cANP((4-23)) did not elevate the cGMP content in control astrocytes, it decreased cAMP content and reduced the expression of G(iα-2), the NADPH oxidase-regulatory protein. The results show the presence of functional NPR-C in astrocytes, activation of which (i) attenuates basal ROS production, and (ii) prevents excessive accumulation of the toxic ROS species, •O(2)(-) by ammonia. Ammonia, ANP and cANP((4-23)) added separately, each stimulated formation of NO(x) (nitrates + nitrites) which was associated with up-regulation of the activity [cANP((4-23))] or/and expression (ammonia) of the endothelial isoform of nitric oxide synthase. However, the ammonia-induced increase of NO(x) was not augmented by co-addition of ANP, and was reduced to the control level by co-addition of cANP((4-23)) , indicating that activation of NPR-C may also reduce nitrosative stress. Future hepatic encephalopathy therapy might include the use of cANP((4-23)) or other NPR-C agonists to control oxidative/nitrosative stress induced by ammonia.
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Affiliation(s)
- Marta Skowrońska
- Department of Neurotoxicology, Mossakowski Medical Research Center, Polish Academy of Sciences, Warsaw, Poland
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21
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Bemeur C, Desjardins P, Butterworth RF. Evidence for oxidative/nitrosative stress in the pathogenesis of hepatic encephalopathy. Metab Brain Dis 2010; 25:3-9. [PMID: 20195724 DOI: 10.1007/s11011-010-9177-y] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Accepted: 09/22/2009] [Indexed: 12/11/2022]
Abstract
Hepatic encephalopathy (HE) is a serious complication of liver failure. HE manifests as a series of neuropsychiatric and neuromuscular symptoms including personality changes, sleep abnormalities, asterixis and muscle rigidity progressing through stupor to coma. The pathophysiologic basis of HE remains unclear. There is general agreement that ammonia plays a key role. In recent years, it has been suggested that oxidative/nitrosative stress constitutes part of the pathophysiologic cascade in HE. Direct evidence for oxidative/nitrosative stress in the pathogenesis of HE has been demonstrated in experimental animal models of acute or chronic liver failure. However, evidence from studies in HE patients is limited. This review summarizes this evidence for a role of oxidative/nitrosative stress in relation to ammonia toxicity and to the pathogenesis of HE.
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Affiliation(s)
- Chantal Bemeur
- Neuroscience Research Unit, Hôpital Saint-Luc (CHUM) University of Montreal, Montreal, QC, Canada
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22
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Faropoulos K, Chroni E, Assimakopoulos SF, Mavrakis A, Stamatopoulou V, Toumpeki C, Drainas D, Grintzalis K, Papapostolou I, Georgiou CD, Konstantinou D. Altered occludin expression in brain capillaries induced by obstructive jaundice in rats. Brain Res 2010; 1325:121-7. [PMID: 20170644 DOI: 10.1016/j.brainres.2010.02.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Revised: 01/30/2010] [Accepted: 02/04/2010] [Indexed: 11/18/2022]
Abstract
The development of increased oxidative stress in the context of obstructive cholestasis has been proven in various rats' organs including the brain. The present study aimed to detect alterations of tight junction-associated occludin in rat brain capillaries after bile duct ligation (BDL). In experiment 1, occludin expression was evaluated by Western blot analysis in 5 animals 10 days after BDL and compared with 5 sham-operated ones. In experiment 2, groups of 9 animals each were used to assess occludin levels on the 1st, 5th, and 10th days after BDL and to associate these measurements with the in vivo superoxide radical production measured by means of an ultrasensitive fluorescent assay. The results indicated that occludin expression in BDL animals, as opposed to sham-operated, was significantly reduced at every time point studied, being lowest in the rats remaining on BDL condition for 10 days. Moreover, it was demonstrated that the time-dependent downregulation of occludin expression in the brain endothelial was significantly correlated with the time-dependent increase of brain superoxide radical level, implying a relationship between these two abnormalities. In conclusion, the evidence presented herein suggests the implication of occludin and, therefore, of blood-brain barrier in the pathophysiology of extrahepatic cholestasis.
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Affiliation(s)
- Konstantinos Faropoulos
- Department of Neurosurgery, School of Medicine, Division of Genetics, Cell and Developmental Biology, University of Patras, Patras, Greece
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Bémeur C, Chastre A, Desjardins P, Butterworth RF. No changes in expression of tight junction proteins or blood–brain barrier permeability in azoxymethane-induced experimental acute liver failure. Neurochem Int 2010. [DOI: 10.1016/j.neuint.2009.11.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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24
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Nguyen JH. Subtle BBB alterations in brain edema associated with acute liver failure. Neurochem Int 2010; 56:203-4; author reply 205-7. [DOI: 10.1016/j.neuint.2009.07.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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25
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Chen F, Ohashi N, Li W, Eckman C, Nguyen JH. Disruptions of occludin and claudin-5 in brain endothelial cells in vitro and in brains of mice with acute liver failure. Hepatology 2009; 50:1914-23. [PMID: 19821483 PMCID: PMC2925168 DOI: 10.1002/hep.23203] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
UNLABELLED Brain edema in acute liver failure (ALF) remains lethal. The role of vasogenic mechanisms of brain edema has not been explored. We previously demonstrated that matrix metalloproteinase-9 (MMP-9) contributes to the pathogenesis of brain edema. Here, we show that MMP-9 mediates disruptions in tight junction (TJ) proteins in vitro and in brains of mice with ALF. We transfected murine brain endothelial cells (ECs) with MMP-9 complementary DNA (cDNA) using pc DNA3.1 (+)/Myc-His A expression vector. Tissue inhibitor of matrix metalloproteinases (TIMP-1) cDNA transfection or GM6001 was used to inhibit MMP-9. ALF was induced in mice with azoxymethane. Endogenous overexpression of MMP-9 in brain ECs resulted in significant degradation of the TJ proteins occludin and claudin-5. The alterations in TJ proteins correlated with increased permeability to fluorescein isothiocyanate-dextran molecules. The degradation of TJ proteins and the increased permeability were reversed by TIMP-1 and GM6001. Similar results were found when MMP-9 was exogenously added to brain ECs. We also found that TJ protein degradation was reversed with GM6001 in the brains of mice with ALF. CONCLUSION TJ proteins are significantly perturbed in brains of mice with ALF. These data corroborate the important role of MMP-9 in the vasogenic mechanism of brain edema in ALF.
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Affiliation(s)
- Florence Chen
- Department of Transplantation, Mayo Clinic, Jacksonville, Florida
| | - Norifumi Ohashi
- Department of Transplantation, Mayo Clinic, Jacksonville, Florida
| | - Wensheng Li
- Department of Transplantation, Mayo Clinic, Jacksonville, Florida
| | | | - Justin H. Nguyen
- Department of Transplantation, Mayo Clinic, Jacksonville, Florida
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