1
|
Chen A, Tait C, Minacapelli C, Rustgi V. Pathophysiology of Hepatic Encephalopathy: A Framework for Clinicians. Clin Liver Dis 2024; 28:209-224. [PMID: 38548434 DOI: 10.1016/j.cld.2024.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/02/2024]
Abstract
Hepatic encephalopathy (HE) is a neuropsychiatric syndrome that is observed primarily in patients with liver disease. The pathophysiology is complex and involves many factors including ammonia toxicity, dysregulation of central nervous system activity, and excess inflammatory cytokines. Symptoms of HE range from subclinical to debilitating. HE can be difficult to treat and represents a large burden to patients, their caregivers, and the health-care system because of associated resource utilization. This review article provides an overview of the current understanding of the pathophysiology behind HE and where the current research and treatments are pointing toward.
Collapse
Affiliation(s)
- Alexander Chen
- Internal Medicine, Robert Wood Johnson Medical School, Rutgers Biomedical and Health Sciences (RBHS), Rutgers University, New Brunswick, NJ, USA
| | - Christopher Tait
- Division of Gastroenterology and Hepatology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Carlos Minacapelli
- Division of Gastroenterology and Hepatology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA; Center for Liver Diseases and Masses, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Vinod Rustgi
- Division of Gastroenterology and Hepatology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA; Center for Liver Diseases and Masses, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA.
| |
Collapse
|
2
|
Gairing SJ, Anders J, Kaps L, Nagel M, Michel M, Kremer WM, Hilscher M, Galle PR, Schattenberg JM, Wörns MA, Labenz C. Evaluation of IL-6 for Stepwise Diagnosis of Minimal Hepatic Encephalopathy in Patients With Liver Cirrhosis. Hepatol Commun 2022; 6:1113-1122. [PMID: 35032100 PMCID: PMC9035565 DOI: 10.1002/hep4.1883] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 11/28/2021] [Accepted: 12/06/2021] [Indexed: 11/10/2022] Open
Abstract
Diagnosis of minimal hepatic encephalopathy (MHE) requires psychometric testing, which is time-consuming and often neglected in clinical practice. Elevated Interleukin-6 (IL-6) serum levels have been linked to MHE. The aim of this study was to investigate the usefulness of IL-6 as a biomarker in a stepwise diagnostic algorithm to detect MHE in patients with liver cirrhosis. A total of 197 prospectively recruited patients without clinical signs of hepatic encephalopathy (HE) served as the development cohort. Another independent cohort consisting of 52 patients served for validation purposes. Psychometric Hepatic Encephalopathy Score (PHES) was applied for the diagnosis of MHE. Fifty (25.4%) patients of the development cohort presented with MHE. Median IL-6 levels were more than twice as high in patients with MHE than in patients without HE (16 vs. 7 pg/mL; P < 0.001). On multivariable logistic regression analysis, higher IL-6 levels (odds ratio 1.036; 95% confidence interval [CI] 1.009-1.064; P = 0.008) remained independently associated with the presence of MHE. IL-6 levels ≥ 8pg/mL discriminated best between patients with and without MHE in receiver operating characteristic (ROC) analysis (area under the ROC 0.751). With a cutoff value of ≥7 pg/mL, further elaborate testing with PHES could be avoided in 38% of all patients with a sensitivity of 90% (95% CI 77%-96%) and a negative predictive value (NPV) of 93% (95% CI 84%-98%). This diagnostic accuracy was confirmed in the validation cohort (sensitivity 94%; NPV 93%). Conclusion: Using IL-6 serum levels as a biomarker in a stepwise diagnostic algorithm to detect MHE could substantially reduce the number of patients requiring testing with PHES and in turn the workload. IL-6 may have especially helped in patients who are unable to perform other screening tests.
Collapse
Affiliation(s)
- Simon Johannes Gairing
- Department of Internal Medicine IUniversity Medical Center of the Johannes Gutenberg-UniversityMainzGermany.,Cirrhosis Center MainzUniversity Medical Center of the Johannes Gutenberg UniversityMainzGermany
| | - Julian Anders
- Department of Internal Medicine IUniversity Medical Center of the Johannes Gutenberg-UniversityMainzGermany
| | - Leonard Kaps
- Department of Internal Medicine IUniversity Medical Center of the Johannes Gutenberg-UniversityMainzGermany.,Cirrhosis Center MainzUniversity Medical Center of the Johannes Gutenberg UniversityMainzGermany
| | - Michael Nagel
- Department of Internal Medicine IUniversity Medical Center of the Johannes Gutenberg-UniversityMainzGermany.,Cirrhosis Center MainzUniversity Medical Center of the Johannes Gutenberg UniversityMainzGermany
| | - Maurice Michel
- Department of Internal Medicine IUniversity Medical Center of the Johannes Gutenberg-UniversityMainzGermany.,Cirrhosis Center MainzUniversity Medical Center of the Johannes Gutenberg UniversityMainzGermany
| | - Wolfgang Maximilian Kremer
- Department of Internal Medicine IUniversity Medical Center of the Johannes Gutenberg-UniversityMainzGermany.,Cirrhosis Center MainzUniversity Medical Center of the Johannes Gutenberg UniversityMainzGermany
| | - Max Hilscher
- Department of Internal Medicine IUniversity Medical Center of the Johannes Gutenberg-UniversityMainzGermany.,Cirrhosis Center MainzUniversity Medical Center of the Johannes Gutenberg UniversityMainzGermany
| | - Peter Robert Galle
- Department of Internal Medicine IUniversity Medical Center of the Johannes Gutenberg-UniversityMainzGermany.,Cirrhosis Center MainzUniversity Medical Center of the Johannes Gutenberg UniversityMainzGermany
| | - Jörn M Schattenberg
- Department of Internal Medicine IUniversity Medical Center of the Johannes Gutenberg-UniversityMainzGermany.,Metabolic Liver Research ProgramUniversity Medical Center of the Johannes Gutenberg UniversityMainzGermany
| | - Marcus-Alexander Wörns
- Department of Internal Medicine IUniversity Medical Center of the Johannes Gutenberg-UniversityMainzGermany.,Cirrhosis Center MainzUniversity Medical Center of the Johannes Gutenberg UniversityMainzGermany.,Department of Gastroenterology, Hematology, Oncology and EndocrinologyKlinikum Dortmund GmbHDortmundGermany
| | - Christian Labenz
- Department of Internal Medicine IUniversity Medical Center of the Johannes Gutenberg-UniversityMainzGermany.,Cirrhosis Center MainzUniversity Medical Center of the Johannes Gutenberg UniversityMainzGermany
| |
Collapse
|
3
|
Kronsten VT, Shawcross DL. Hepatic encephalopathy and depression in chronic liver disease: is the common link systemic inflammation? Anal Biochem 2021; 636:114437. [PMID: 34715068 DOI: 10.1016/j.ab.2021.114437] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 09/26/2021] [Accepted: 10/22/2021] [Indexed: 02/08/2023]
Abstract
Hepatic encephalopathy and depression share a number of clinical features, such as cognitive impairment and psychomotor retardation, and are highly prevalent in patients with chronic liver disease. Both conditions signify a poor prognosis, carry an increased mortality and are major determinants of reduced health related quality of life. The pathophysiology of hepatic encephalopathy is complex. Whilst cerebral accumulation of ammonia is well-recognised as being central to the development of hepatic encephalopathy, systemic inflammation, which acts in synergy with hyperammonaemia, is emerging as a key driver in its development. The pro-inflammatory state is also widely documented in depression, and peripheral to brain communication occurs resulting in central inflammation, behavioural changes and depressive symptoms. Gut dysbiosis, with a similar reduction in beneficial bacteria, increase in pathogens and decreased bacterial diversity, has been observed in both hepatic encephalopathy and depression, and it may be that the resultant increased bacterial translocation causes their shared inflammatory pathophysiology. Whilst the literature on a positive association between hepatic encephalopathy and depression in cirrhosis remains to be substantiated, there is evolving evidence that treatment with psychobiotics may be of dual benefit, improving cognition and mood in cirrhosis.
Collapse
Affiliation(s)
- Victoria Tatiana Kronsten
- Institute of Liver Studies, School of Immunology and Microbial Sciences, Faculty of Life Sciences and Medicine, King's College London, UK.
| | - Debbie Lindsay Shawcross
- Institute of Liver Studies, School of Immunology and Microbial Sciences, Faculty of Life Sciences and Medicine, King's College London, UK
| |
Collapse
|
4
|
Hiramine Y, Uto H, Mawatari S, Kanmura S, Imamura Y, Hiwaki T, Saishoji A, Kakihara A, Maenohara S, Tokushige K, Ido A. Efficacy of rifaximin, a poorly absorbed rifamycin antimicrobial agent, for hepatic encephalopathy in Japanese patients. Hepatol Res 2021; 51:445-460. [PMID: 33533150 DOI: 10.1111/hepr.13622] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 12/27/2020] [Accepted: 01/15/2021] [Indexed: 12/21/2022]
Abstract
AIM Rifaximin is recommended as treatment for hepatic encephalopathy (HE) that targets intestinal bacterial flora. Although combined use with synthetic disaccharides is the standard of care worldwide, the therapeutic effects of rifaximin for overt encephalopathy (OHE) in Japanese patients have not been examined sufficiently. We examined the therapeutic effects of rifaximin for OHE in Japanese patients. METHODS A total of 76 patients who developed OHE of West Haven grade II or higher at least once within the 12 months before starting rifaximin were included. Blood ammonia levels and the incidence of OHE during the 12 months before and after starting rifaximin therapy were compared in a before-and-after study. Rifaximin efficacy and predictors of efficacy were also examined. RESULTS Post-treatment blood ammonia levels were significantly lower than pretreatment levels. The mean annual number of OHE incidents and intravenous branched-chain amino acid preparations used per patient were significantly lower after starting rifaximin therapy (2.51 vs. 0.76 times/year, p < 0.001; and 71.9 vs. 20.7 preparations/year, p = 0.003, respectively). The cumulative incidence of hospitalizations associated with HE significantly decreased after rifaximin therapy (hazard ratio 0.187; p < 0.001). The efficacy rate, defined as the proportion of patients without OHE during the administration of rifaximin for 1 year after starting rifaximin therapy, was 65.8%. Serum albumin ≥2.7 g/dl was an independent predictor of efficacy. CONCLUSION Rifaximin was associated with decreased blood ammonia levels, lower incidence of OHE, and fewer hospitalizations in Japanese patients with HE. In addition, serum albumin level was an important predictor on efficacy of rifaximin.
Collapse
Affiliation(s)
- Yasunari Hiramine
- Department of Internal Medicine, Kagoshima Kouseiren Hospital, Kagoshima, Japan
| | - Hirofumi Uto
- Center for Digestive and Liver Diseases, Miyazaki Medical Center Hospital, Miyazaki, Japan.,Digestive and Lifestyle Diseases, Department of Human and Environmental Sciences, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Seiichi Mawatari
- Digestive and Lifestyle Diseases, Department of Human and Environmental Sciences, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Shuji Kanmura
- Digestive and Lifestyle Diseases, Department of Human and Environmental Sciences, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Yasushi Imamura
- Department of Internal Medicine, Kagoshima Kouseiren Hospital, Kagoshima, Japan
| | - Takuya Hiwaki
- Department of Internal Medicine, Kagoshima Kouseiren Hospital, Kagoshima, Japan
| | - Akiko Saishoji
- Department of Internal Medicine, Kagoshima Kouseiren Hospital, Kagoshima, Japan.,Digestive and Lifestyle Diseases, Department of Human and Environmental Sciences, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Atsuko Kakihara
- Department of Internal Medicine, Kagoshima Kouseiren Hospital, Kagoshima, Japan.,Digestive and Lifestyle Diseases, Department of Human and Environmental Sciences, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Shigeho Maenohara
- Department of Surgery, Kagoshima Kouseiren Hospital, Kagoshima, Japan
| | - Koichi Tokushige
- Department of Internal Medicine, Kagoshima Kouseiren Hospital, Kagoshima, Japan
| | - Akio Ido
- Digestive and Lifestyle Diseases, Department of Human and Environmental Sciences, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| |
Collapse
|
5
|
Spinillo S, Golini L, Motta L. Brain MRI findings in a dog with late onset epileptic seizure after portosystemic shunt attenuation. VETERINARY RECORD CASE REPORTS 2020. [DOI: 10.1136/vetreccr-2020-001159] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Simone Spinillo
- Department of NeurologyNorth West Veterinary SpecialistsRuncornCheshireUK
| | - Lorenzo Golini
- Veterinary Neurology and Neurosurgery ServiceClinica Veterinaria San MarcoVeggianoItaly
| | - Luca Motta
- Department of NeurologyNorth West Veterinary SpecialistsRuncornCheshireUK
| |
Collapse
|
6
|
Shibasaki M, Hatanaka T, Shimada Y, Nagashima T, Namikawa M, Saito S, Hosonuma K, Naganuma A, Takizawa D, Arai H, Kosone T, Takagi H, Sato K, Kakizaki S, Uraoka T. Efficacy and safety of rifaximin treatment in Japanese patients with hepatic encephalopathy. KANZO 2020; 61:1-10. [DOI: 10.2957/kanzo.61.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/28/2023]
Affiliation(s)
| | - Takeshi Hatanaka
- Department of Gastroenterology, Gunma Saiseikai Maebashi Hospital
| | | | - Tamon Nagashima
- Department of Gastroenterology, Shibukawa Medical Center, National Hospital Organization
| | | | - Shuichi Saito
- Department of Gastroenterology, Tomioka General Hospital
| | | | - Atsushi Naganuma
- Department of Gastroenterology, Takasaki General Medical Center, National Hospital Organization
| | | | - Hirotaka Arai
- Department of Gastroenterology, Maebashi Red Cross Hospital
| | - Takashi Kosone
- Department of Gastroenterology and Hepatology, Kusunoki Hospital
| | - Hitoshi Takagi
- Department of Gastroenterology and Hepatology, Kusunoki Hospital
| | - Ken Sato
- Department of Gastroenterology and Hepatology, Gunma University Graduate School of Medicine
| | - Satoru Kakizaki
- Department of Gastroenterology and Hepatology, Gunma University Graduate School of Medicine
| | - Toshio Uraoka
- Department of Gastroenterology and Hepatology, Gunma University Graduate School of Medicine
| |
Collapse
|
7
|
Jaeger V, DeMorrow S, McMillin M. The Direct Contribution of Astrocytes and Microglia to the Pathogenesis of Hepatic Encephalopathy. J Clin Transl Hepatol 2019; 7:352-361. [PMID: 31915605 PMCID: PMC6943208 DOI: 10.14218/jcth.2019.00025] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 10/07/2019] [Accepted: 10/24/2019] [Indexed: 02/06/2023] Open
Abstract
Hepatic encephalopathy is a neurological complication resulting from loss of hepatic function and is associated with poor clinical outcomes. During acute liver failure over 20% of mortality can be associated with the development of hepatic encephalopathy. In patients with liver cirrhosis, 1-year survival for those that develop overt hepatic encephalopathy is under 50%. The pathogenesis of hepatic encephalopathy is complicated due to the multiple disruptions in homeostasis that occur following a reduction in liver function. Of these, elevations of ammonia and neuroinflammation have been shown to play a significant contributing role to the development of hepatic encephalopathy. Disruption of the urea cycle following liver dysfunction leads to elevations of circulating ammonia, which enter the brain and disrupt the functioning of astrocytes. This results in dysregulation of metabolic pathways in astrocytes, oxidative stress and cerebral edema. Besides ammonia, circulating chemokines and cytokines are increased following liver injury, leading to activation of microglia and a subsequent neuroinflammatory response. The combination of astrocyte dysfunction and microglia activation are significant contributing factors to the pathogenesis of hepatic encephalopathy.
Collapse
Affiliation(s)
- Victoria Jaeger
- Baylor Scott & White Health, Department of Internal Medicine, Temple, TX, USA
| | - Sharon DeMorrow
- Texas A&M University Health Science Center, Department of Medical Physiology, Temple, TX, USA
- Central Texas Veterans Health Care System, Temple, TX, USA
- University of Texas at Austin, Dell Medical School, Department of Internal Medicine, Austin, TX, USA
- University of Texas at Austin, College of Pharmacy, Austin, TX, USA
| | - Matthew McMillin
- Texas A&M University Health Science Center, Department of Medical Physiology, Temple, TX, USA
- Central Texas Veterans Health Care System, Temple, TX, USA
- University of Texas at Austin, Dell Medical School, Department of Internal Medicine, Austin, TX, USA
- Correspondence to: Matthew McMillin, University of Texas at Austin Dell Medical School, 1601 Trinity Street, Building B, Austin, TX 78701, USA. Tel: +1-512-495-5037, Fax: +1-512-495-5839, E-mail:
| |
Collapse
|
8
|
Bai Z, Bernardi M, Yoshida EM, Li H, Guo X, Méndez-Sánchez N, Li Y, Wang R, Deng J, Qi X. Albumin infusion may decrease the incidence and severity of overt hepatic encephalopathy in liver cirrhosis. Aging (Albany NY) 2019; 11:8502-8525. [PMID: 31596729 PMCID: PMC6814610 DOI: 10.18632/aging.102335] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 09/22/2019] [Indexed: 02/07/2023]
Abstract
BACKGROUND The role of human albumin infusion for the prevention and treatment of overt hepatic encephalopathy (HE) in liver cirrhosis remains unclear. RESULTS Among the 708 patients without pre-existing overt HE, albumin infusion significantly decreased the incidence of overt HE (4.20% versus 12.70%, P<0.001) and in-hospital mortality (1.70% versus 5.40%, P=0.008). Among the 182 patients with overt HE at admission or during hospitalization, albumin infusion significantly improved overt HE (84.60% versus 68.10%, P=0.009) and decreased in-hospital mortality (7.70% versus 19.80%, P=0.018). Meta-analysis of 6 studies found that albumin infusion might decrease the risk of overt HE (OR=1.63, P=0.07), but the difference was not statistically significant. Meta-analysis of 3 studies found that albumin infusion significantly improved overt HE (OR=2.40, P=0.04). CONCLUSIONS Based on the results of our retrospective study and meta-analysis, albumin infusion might prevent from the occurrence of overt HE and improve the severity of overt HE in cirrhosis. Our retrospective study also suggested that albumin infusion improved the outcomes of cirrhotic patients regardless of overt HE. METHODS Cirrhotic patients consecutively admitted between January 2010 and June 2014 were considered in a retrospective study. A 1:1 propensity score matching analysis was performed. Additionally, publications regarding albumin infusion for the management of overt HE were systematically searched. Meta-analyses were performed by random-effect model. Odds ratio (OR) was calculated.
Collapse
Affiliation(s)
- Zhaohui Bai
- Department of Gastroenterology, General Hospital of Northern Theater Command (formerly called General Hospital of Shenyang Military Area), Shenyang, P.R. China
- Postgraduate College, Shenyang Pharmaceutical University, Shenyang, P.R. China
| | - Mauro Bernardi
- Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
| | - Eric M. Yoshida
- Division of Gastroenterology, Vancouver General Hospital, Vancouver, British Columbia, Canada
| | - Hongyu Li
- Department of Gastroenterology, General Hospital of Northern Theater Command (formerly called General Hospital of Shenyang Military Area), Shenyang, P.R. China
| | - Xiaozhong Guo
- Department of Gastroenterology, General Hospital of Northern Theater Command (formerly called General Hospital of Shenyang Military Area), Shenyang, P.R. China
| | - Nahum Méndez-Sánchez
- Liver Research Unit, Medica Sur Clinic and Foundation and Faculty of Medicine, National Autonomous University of Mexico, Mexico
| | - Yingying Li
- Department of Gastroenterology, General Hospital of Northern Theater Command (formerly called General Hospital of Shenyang Military Area), Shenyang, P.R. China
| | - Ran Wang
- Department of Gastroenterology, General Hospital of Northern Theater Command (formerly called General Hospital of Shenyang Military Area), Shenyang, P.R. China
| | - Jiao Deng
- Department of Pharmacology, General Hospital of Northern Theater Command, (formerly called General Hospital of Shenyang Military Area), Shenyang, P.R. China
| | - Xingshun Qi
- Department of Gastroenterology, General Hospital of Northern Theater Command (formerly called General Hospital of Shenyang Military Area), Shenyang, P.R. China
| |
Collapse
|
9
|
Management of Hepatic Encephalopathy in the Neurocritical Care Unit. Neurocrit Care 2019. [DOI: 10.1017/9781107587908.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
10
|
Campion D, Giovo I, Ponzo P, Saracco GM, Balzola F, Alessandria C. Dietary approach and gut microbiota modulation for chronic hepatic encephalopathy in cirrhosis. World J Hepatol 2019; 11:489-512. [PMID: 31293718 PMCID: PMC6603507 DOI: 10.4254/wjh.v11.i6.489] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 05/16/2019] [Accepted: 05/21/2019] [Indexed: 02/06/2023] Open
Abstract
Hepatic encephalopathy (HE) is a common and serious neuropsychiatric complication of cirrhosis, acute liver failure, and porto-systemic shunting. HE largely contributes to the morbidity of patients with liver disease, severely affecting the quality of life of both patients and their relatives and being associated with poor prognosis. Its presentation is largely variable, manifesting with a broad spectrum of cognitive abnormalities ranging from subtle cognitive impairment to coma. The pathogenesis of HE is complex and has historically been linked with hyperammonemia. However, in the last years, it has become evident that the interplay of multiple actors, such as intestinal dysbiosis, gut hyperpermeability, and neuroinflammation, is of crucial importance in its genesis. Therefore, HE can be considered a result of a dysregulated gut-liver-brain axis function, where cognitive impairment can be reversed or prevented by the beneficial effects induced by “gut-centric” therapies, such as non-absorbable disaccharides, non-absorbable antibiotics, probiotics, prebiotics, and fecal microbiota transplantation. In this context dietary modifications, by modulating the intestinal milieu, can also provide significant benefit to cirrhotic patients with HE. This review will provide a comprehensive insight into the mechanisms responsible for gut-liver-brain axis dysregulation leading to HE in cirrhosis. Furthermore, it will explore the currently available therapies and the most promising future treatments for the management of patients with HE, with a special focus on the dietary approach.
Collapse
Affiliation(s)
- Daniela Campion
- Division of Gastroenterology and Hepatology, Città della Salute e della Scienza di Torino Hospital, University of Turin, 10126 Turin, Italy
| | - Ilaria Giovo
- Division of Gastroenterology and Hepatology, Città della Salute e della Scienza di Torino Hospital, University of Turin, 10126 Turin, Italy
| | - Paola Ponzo
- Division of Gastroenterology and Hepatology, Città della Salute e della Scienza di Torino Hospital, University of Turin, 10126 Turin, Italy
| | - Giorgio M Saracco
- Division of Gastroenterology and Hepatology, Città della Salute e della Scienza di Torino Hospital, University of Turin, 10126 Turin, Italy
| | - Federico Balzola
- Division of Gastroenterology and Hepatology, Città della Salute e della Scienza di Torino Hospital, University of Turin, 10126 Turin, Italy
| | - Carlo Alessandria
- Division of Gastroenterology and Hepatology, Città della Salute e della Scienza di Torino Hospital, University of Turin, 10126 Turin, Italy
| |
Collapse
|
11
|
Abstract
Neuropathology of hepatic encephalopathy (HE) in cirrhosis is primarily astroglial in nature characterized by Alzheimer type 2 astrocytosis together with activation of microglia indicative of neuroinflammation. Focal loss of neurons may also occur in the basal ganglia, thalamus and cerebellum. Pathophysiology of HE in cirrhosis is multifactorial, involving brain accumulation of ammonia and manganese, systemic and central inflammation, nutritional/metabolic factors and activation of the GABAergic neurotransmitter system. Neuroimaging and spectroscopic techniques reveal early deactivation of the anterior cingulate cortex in parallel with neuropsychological impairment. T1-weighted MR signal hyperintensities in basal ganglia resulting from manganese lead to a novel entity, 'Parkinsonism in cirrhosis'. Elucidation of the pathophysiological mechanisms has resulted in novel therapeutic approaches to HE aimed at reduction of brain ammonia, reduction of systemic and central inflammation, and reduction of GABAergic tone via the discovery of antagonists of the neurosteroid-modulatory site on the GABA receptor complex.
Collapse
Affiliation(s)
- Roger F Butterworth
- Department of Medicine, University of Montreal, 45143 Cabot Trail, Englishtown, NS, B0C 1H0, Canada.
| |
Collapse
|
12
|
Hepatic encephalopathy 2018: A clinical practice guideline by the Italian Association for the Study of the Liver (AISF). Dig Liver Dis 2019; 51:190-205. [PMID: 30606696 DOI: 10.1016/j.dld.2018.11.035] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 11/27/2018] [Accepted: 11/28/2018] [Indexed: 12/11/2022]
Abstract
Hepatic encephalopathy (HE) is a common, worrisome and sometimes difficult to manage complication of end-stage liver disease. HE is often recurrent, requiring multiple hospital admissions. It can have serious implications in terms of a patient's ability to perform complex tasks (for example driving), their earning capacity, their social and family roles. This guideline reviews current knowledge on HE definition, pathophysiology, diagnosis and treatment, both by general principles and by way of a summary of available drugs and treatment strategies. The quality of the published, pertinent evidence is graded, and practical recommendations are made. Where possible, these are placed within the Italian health service context, with reference to local diagnosis and management experience.
Collapse
|
13
|
Wang W, Lu H, Lu X, Wang D, Wang Z, Dai W, Wang J, Liu P. Effect of tumor necrosis factor-α on the expression of the ammonia transporter Rhcg in the brain in mice with acute liver failure. J Neuroinflammation 2018; 15:234. [PMID: 30134917 PMCID: PMC6106833 DOI: 10.1186/s12974-018-1264-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 07/31/2018] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Ammonia and tumor necrosis factor-alpha (TNF-α) play important roles in the mechanisms of hepatic encephalopathy (HE). Rhesus glycoprotein C (Rhcg) is important for ammonia transport especially in the kidney. The aim of the present study was to investigate the role of Rhcg in the brain in acute liver failure (ALF) and the effect of TNF-α on Rhcg expression. METHODS ALF mouse models were generated by treatment with D-galactosamine (D-GalN) and lipopolysaccharide (LPS), or D-GalN and TNF-α. ALF induction was blocked by pretreatment with anti-TNF-α IgG. The levels of serum TNF-α were determined by ELISA. Blood ammonia and brain ammonia concentrations were detected using an ammonia assay kit. The expression and distribution of Rhcg in the brain tissues of ALF mice were examined by western blotting, real-time PCR, immunohistochemical, and immunofluorescence analyses. RESULTS Serum TNF-α levels were increased in the LPS/D-GalN group. Blood and brain ammonia were increased in the LPS/D-GalN- and TNF-α/D-GalN-induced ALF groups. Rhcg mRNA and protein levels were elevated in both ALF groups, consistent with the increase in blood and brain ammonia. Rhcg was mainly expressed in vascular endothelial cells and astrocytes. Pretreatment with anti-TNF-α IgG antibody downregulated Rhcg in brain tissues in the LPS/D-GalN group, prevented the occurrence of ALF, and reduced blood and brain ammonia levels in the LPS/D-GalN group. CONCLUSION TNF-α promoted the transport of ammonia from the blood to brain tissues and exacerbated the toxic effects of ammonia by upregulating Rhcg.
Collapse
Affiliation(s)
- Wen Wang
- Department of Infectious Diseases, The First Affiliated Hospital of China Medical University, 155 Nanjing North Street, Shenyang, 110001, Liaoning Province, People's Republic of China
| | - Hui Lu
- Department of Infectious Diseases, The First Affiliated Hospital of China Medical University, 155 Nanjing North Street, Shenyang, 110001, Liaoning Province, People's Republic of China
| | - Xu Lu
- Department of Infectious Diseases, The First Affiliated Hospital of China Medical University, 155 Nanjing North Street, Shenyang, 110001, Liaoning Province, People's Republic of China
| | - Donglei Wang
- Department of Infectious Diseases, The First Affiliated Hospital of China Medical University, 155 Nanjing North Street, Shenyang, 110001, Liaoning Province, People's Republic of China
| | - Zhaohan Wang
- Gastroenterology and Hepatology Department, Jiangxi Provincial People's Hospital, Nanchang City, Jiangxi Province, People's Republic of China
| | - Wenying Dai
- Department of Intervention, the Sixth People's Hospital of Shenyang, Shenyang City, Liaoning Province, People's Republic of China
| | - Jinyong Wang
- Department of Infectious Diseases, The First Affiliated Hospital of China Medical University, 155 Nanjing North Street, Shenyang, 110001, Liaoning Province, People's Republic of China
| | - Pei Liu
- Department of Infectious Diseases, The First Affiliated Hospital of China Medical University, 155 Nanjing North Street, Shenyang, 110001, Liaoning Province, People's Republic of China. .,The Institute of Liver Diseases of China Medical University, Shenyang, Liaoning Province, China.
| |
Collapse
|
14
|
Strickland R, Tivers MS, Adamantos SE, Harcourt-Brown TR, Fowkes RC, Lipscomb VJ. Incidence and risk factors for neurological signs after attenuation of single congenital portosystemic shunts in 253 dogs. Vet Surg 2018; 47:745-755. [DOI: 10.1111/vsu.12925] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 01/10/2018] [Accepted: 03/02/2018] [Indexed: 01/15/2023]
Affiliation(s)
- Rhiannon Strickland
- Department of Clinical Science and Services; Royal Veterinary College, University of London; London United Kingdom
| | - Michael S. Tivers
- School of Veterinary Sciences; University of Bristol; Bristol United Kingdom
| | | | | | - Robert C. Fowkes
- Department of Comparative Biomedical Sciences; Royal Veterinary College, University of London; London United Kingdom
| | - Victoria J. Lipscomb
- Department of Clinical Science and Services; Royal Veterinary College, University of London; London United Kingdom
| |
Collapse
|
15
|
Abstract
BACKGROUND Increasing evidence reveals a close and reciprocal link between acute-on-chronic liver failure (ACLF) and immunodysfunction. METHODS A literature search in PubMed and abstract databases of relevant congresses was performed. RESULTS Important characteristics of liver cirrhosis like tissue hypoxia, cell death, or bacterial translocation maintain a state of chronic inflammation. Precipitating events of ACLF such as infections or alcoholic hepatitis are capable of strongly augmenting cirrhosis-associated systemic inflammation to grades sufficient to induce ACLF-defining organ failures. Chronic systemic inflammation, however, is causally linked to profound immunosuppression. As a consequence, patients with liver cirrhosis and in particular with ACLF are at high risk for severe infections. Promising strategies to ameliorate immunodysfunction, like albumin substitution, administration of recombinant interleukin-22 or granulocyte colony-stimulating factor, antibiotic prophylaxis, or anticoagulation, are under development and offer the chance to specifically prevent and treat ACLF. CONCLUSION A better understanding of the immunopathology of ACLF will likely translate into the implementation of specific therapeutic modalities to prevent and overcome ACLF.
Collapse
Affiliation(s)
- Christian M. Lange
- Medizinische Klinik 1, Klinikum der Johann Wolfgang Goethe-Universität, Frankfurt/Main, Germany
| | - Richard Moreau
- Centre de Recherche sur l'Inflammation (CRI), Institut National de la Santé et de la Recherche Médicale (INSERM), Université Paris-Diderot, Paris, France
| |
Collapse
|
16
|
Aphasia in a patient with acute hepatic encephalopathy associated with multifocal cortical brain lesions. NEUROLOGÍA (ENGLISH EDITION) 2018. [DOI: 10.1016/j.nrleng.2016.03.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
|
17
|
Hamasaki MY, Machado MCC, Pinheiro da Silva F. Animal models of neuroinflammation secondary to acute insults originated outside the brain. J Neurosci Res 2017; 96:371-378. [DOI: 10.1002/jnr.24184] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 09/11/2017] [Accepted: 09/12/2017] [Indexed: 12/15/2022]
Affiliation(s)
- Mike Yoshio Hamasaki
- Laboratório de Emergências Clínicas, Faculdade de Medicina FMUSP; Universidade de São Paulo; São Paulo SP Brazil
| | | | - Fabiano Pinheiro da Silva
- Laboratório de Emergências Clínicas, Faculdade de Medicina FMUSP; Universidade de São Paulo; São Paulo SP Brazil
| |
Collapse
|
18
|
Zhang L, Tan J, Jiang X, Qian W, Yang T, Sun X, Chen Z, Zhu Q. Neuron-derived CCL2 contributes to microglia activation and neurological decline in hepatic encephalopathy. Biol Res 2017; 50:26. [PMID: 28870240 PMCID: PMC5584513 DOI: 10.1186/s40659-017-0130-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 07/24/2017] [Indexed: 01/12/2023] Open
Abstract
Background CCL2 was up-regulated in neurons and involved in microglia activation and neurological decline in mice suffering from hepatic encephalopathy (HE). However, no data exist concerning the effect of neuron-derived CCL2 on microglia activation in vitro. Methods The rats were pretreated with CCL2 receptor inhibitors (INCB or C021, 1 mg/kg/day i.p.) for 3 days prior to thioacetamide (TAA) administration (300 mg/kg/day i.p.) for inducing HE model. At 8 h following the last injection (and every 4 h after), the grade of encephalopathy was assessed. Blood and whole brains were collected at coma for measuring CCL2 and Iba1 expression. In vitro, primary neurons were stimulated with TNF-α, and then the medium were collected for addition to microglia cultures with or without INCB or C021 pretreatment. The effect of the medium on microglia proliferation and activation was evaluated after 24 h. Results CCL2 expression and microglia activation were elevated in the cerebral cortex of rats received TAA alone. CCL2 receptors inhibition improved neurological score and reduced cortical microglia activation. In vitro, TNF-α treatment induced CCL2 release by neurons. Medium from TNF-α stimulated neurons caused microglia proliferation and M1 markers expression, including iNOS, COX2, IL-6 and IL-1β, which could be suppressed by INCB or C021 pretreatment. The medium could also facilitate p65 nuclear translocation and IκBα phosphorylation, and NF-κB inhibition reduced the increased IL-6 and IL-1β expression induced by the medium. Conclusion Neuron-derived CCL2 contributed to microglia activation and neurological decline in HE. Blocking CCL2 or inhibiting microglia excessive activation may be potential strategies for HE.
Collapse
Affiliation(s)
- Li Zhang
- Department of Radiology, The Second People's Hospital of Lanzhou, No. 388 Jingyuan Road, Chengguan District, Lanzhou, 730046, China
| | - Jinyun Tan
- Department of Radiology, The Second People's Hospital of Lanzhou, No. 388 Jingyuan Road, Chengguan District, Lanzhou, 730046, China
| | - Xiaoping Jiang
- Department of Radiology, The Second People's Hospital of Lanzhou, No. 388 Jingyuan Road, Chengguan District, Lanzhou, 730046, China.
| | - Weiwei Qian
- Department of Radiology, The Second People's Hospital of Lanzhou, No. 388 Jingyuan Road, Chengguan District, Lanzhou, 730046, China
| | - Ting Yang
- Department of Radiology, The Second People's Hospital of Lanzhou, No. 388 Jingyuan Road, Chengguan District, Lanzhou, 730046, China
| | - Xijun Sun
- Department of Radiology, The Second People's Hospital of Lanzhou, No. 388 Jingyuan Road, Chengguan District, Lanzhou, 730046, China
| | - Zhaohui Chen
- Department of Radiology, The Second People's Hospital of Lanzhou, No. 388 Jingyuan Road, Chengguan District, Lanzhou, 730046, China
| | - Qiwen Zhu
- Department of Radiology, The Second People's Hospital of Lanzhou, No. 388 Jingyuan Road, Chengguan District, Lanzhou, 730046, China
| |
Collapse
|
19
|
Affiliation(s)
- Eelco F M Wijdicks
- From the Division of Critical Care Neurology, Mayo Clinic, Rochester, MN
| |
Collapse
|
20
|
Donnelly MC, Hayes PC, Simpson KJ. Role of inflammation and infection in the pathogenesis of human acute liver failure: Clinical implications for monitoring and therapy. World J Gastroenterol 2016; 22:5958-5970. [PMID: 27468190 PMCID: PMC4948263 DOI: 10.3748/wjg.v22.i26.5958] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2016] [Revised: 05/25/2016] [Accepted: 06/15/2016] [Indexed: 02/06/2023] Open
Abstract
Acute liver failure is a rare and devastating clinical condition. At present, emergency liver transplantation is the only life-saving therapy in advanced cases, yet the feasibility of transplantation is affected by the presence of systemic inflammation, infection and resultant multi-organ failure. The importance of immune dysregulation and acquisition of infection in the pathogenesis of acute liver failure and its associated complications is now recognised. In this review we discuss current thinking regarding the role of infection and inflammation in the pathogenesis of and outcome in human acute liver failure, the implications for the management of such patients and suggest directions for future research.
Collapse
|
21
|
Sheen JM, Chen YC, Hsu MH, Tain YL, Yu HR, Huang LT. Combined Intraperitoneal and Intrathecal Etanercept Reduce Increased Brain Tumor Necrosis Factor-Alpha and Asymmetric Dimethylarginine Levels and Rescues Spatial Deficits in Young Rats after Bile Duct Ligation. Front Cell Neurosci 2016; 10:167. [PMID: 27445694 PMCID: PMC4917524 DOI: 10.3389/fncel.2016.00167] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 06/09/2016] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Rats subjected to bile duct ligation (BDL) exhibit increased systemic oxidative stress and brain dysfunction characteristic of hepatic encephalopathy (HE), including fatigue, neurotransmitter alterations, cognitive and motor impairment, and brain inflammation. The levels of tumor necrosis factor-alpha (TNF-α) and asymmetric dimethylarginine (ADMA) are both increased in plasma and brain in encephalopathy induced by chronic liver failure. This study first determined the temporal profiles of TNF-α and ADMA in the plasma, brain cortex, and hippocampus in young BDL rats. Next, we examined whether etanercept was beneficial in preventing brain damage. METHODS Young rats underwent sham ligation or BDL at day 17 ± 1 for 4 weeks. Treatment group rats were administered etanercept (10 mg/kg) intraperitoneally (IP) three times per week with or without etanercept (100 μg) intrathecally (IT) three times in total. RESULTS We found increased plasma TNF-α, soluble tumor necrosis factor receptor 1 (sTNFR1), soluble tumor necrosis factor receptor 2 (sTNFR2), and ADMA levels, increased cortical TNF-α mRNA and protein and ADMA, and hippocampal TNF-α mRNA and protein, and spatial defects in young BDL rats. The increase in cortex TNF-α mRNA and ADMA were reduced by IP etanercept or combined IP and IT etanercept. Dually IP/IT etanercept administration reduced the increased cortical and hippocampal TNF-α mRNA and protein level as well as spatial deficits. CONCLUSIONS We conclude that combined intraperitoneal and intrathecal etanercept reduce increased brain TNF-α and ADMA levels and rescues spatial deficits in young rats after BDL.
Collapse
Affiliation(s)
- Jiunn-Ming Sheen
- Department of Pediatrics, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of MedicineKaohsiung, Taiwan; Graduate Institute of Clinical Medical Sciences, Chang Gung University College of MedicineKaohsiung, Taiwan
| | - Yu-Chieh Chen
- Department of Pediatrics, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine Kaohsiung, Taiwan
| | - Mei-Hsin Hsu
- Department of Pediatrics, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine Kaohsiung, Taiwan
| | - You-Lin Tain
- Department of Pediatrics, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine Kaohsiung, Taiwan
| | - Hong-Ren Yu
- Department of Pediatrics, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine Kaohsiung, Taiwan
| | - Li-Tung Huang
- Department of Pediatrics, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine Kaohsiung, Taiwan
| |
Collapse
|
22
|
Falgàs N, Alfaro I, Crespo G, Berenguer J, García-Pagán JC, Muñoz E. Aphasia in a patient with acute hepatic encephalopathy associated with multifocal cortical brain lesions. Neurologia 2016; 33:S0213-4853(16)30026-3. [PMID: 27157523 DOI: 10.1016/j.nrl.2016.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2016] [Accepted: 03/08/2016] [Indexed: 11/17/2022] Open
Affiliation(s)
- N Falgàs
- Servicio de Neurología, Hospital Clínic de Barcelona, Barcelona, España
| | - I Alfaro
- Unidad de Hepatología, Hospital Clínic de Barcelona, Barcelona, España
| | - G Crespo
- Unidad de Hepatología, Hospital Clínic de Barcelona, Barcelona, España
| | - J Berenguer
- Servicio de Radiología, Hospital Clínic de Barcelona, Barcelona, España
| | - J C García-Pagán
- Unidad de Hepatología, Hospital Clínic de Barcelona, Barcelona, España; Laboratorio de Hemodinámica Hepática, CIBERehd, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, Hospital Clínic Barcelona, Barcelona, España
| | - E Muñoz
- Servicio de Neurología, Hospital Clínic de Barcelona, Barcelona, España.
| |
Collapse
|
23
|
Abstract
Hepatic encephalopathy (HE) is a severe neuropsychiatric complication of acute and chronic liver dysfunction, and is characterized by a spectrum that ranges from mild neuropsychological disturbances to coma. Although ammonia plays a critical role in the pathogenesis of HE, the plasma concentrations of ammonia and manifest symptoms of HE are not always consistent in patients with HE. Recently, a substantial body of evidence has indicated that inflammation acts in concert with ammonia in the pathogenesis of HE. Meanwhile, emerging novel and potential therapeutic strategies, including N-acetylcysteine, hypothermia, minocycline, non-steroidal anti-inflammatory drugs, tumour necrosis factor-alpha antagonists and p38 inhibitors, have been reported to ameliorate systemic inflammation and neuroinflammation, improve or reverse neuropsychiatric manifestations, and prevent the onset and progression of HE in patients and/or animal models of acute or chronic liver failure. These results point to the possible therapeutic utility of decreasing inflammation in the treatment of HE, and translation of these experimental results to the clinic may provide novel and promising therapeutic approaches for patients with HE secondary to acute or chronic liver failure. This review will provide an overview of these potential targeted therapies in the prophylaxis and treatment of HE.
Collapse
|
24
|
Luo M, Guo JY, Cao WK. Inflammation: A novel target of current therapies for hepatic encephalopathy in liver cirrhosis. World J Gastroenterol 2015; 21:11815-11824. [PMID: 26557005 PMCID: PMC4631979 DOI: 10.3748/wjg.v21.i41.11815] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 06/19/2015] [Accepted: 09/14/2015] [Indexed: 02/06/2023] Open
Abstract
Hepatic encephalopathy (HE) is a severe neuropsychiatric syndrome that most commonly occurs in decompensated liver cirrhosis and incorporates a spectrum of manifestations that ranges from mild cognitive impairment to coma. Although the etiology of HE is not completely understood, it is believed that multiple underlying mechanisms are involved in the pathogenesis of HE, and one of the main factors is thought to be ammonia; however, the ammonia hypothesis in the pathogenesis of HE is incomplete. Recently, it has been increasingly demonstrated that inflammation, including systemic inflammation, neuroinflammation and endotoxemia, acts in concert with ammonia in the pathogenesis of HE in cirrhotic patients. Meanwhile, a good number of studies have found that current therapies for HE, such as lactulose, rifaximin, probiotics and the molecular adsorbent recirculating system, could inhibit different types of inflammation, thereby improving the neuropsychiatric manifestations and preventing the progression of HE in cirrhotic patients. The anti-inflammatory effects of these current therapies provide a novel therapeutic approach for cirrhotic patients with HE. The purpose of this review is to describe the inflammatory mechanisms behind the etiology of HE in cirrhosis and discuss the current therapies that target the inflammatory pathogenesis of HE.
Collapse
|
25
|
Jayakumar AR, Rama Rao KV, Norenberg MD. Neuroinflammation in hepatic encephalopathy: mechanistic aspects. J Clin Exp Hepatol 2015; 5:S21-8. [PMID: 26041953 PMCID: PMC4442850 DOI: 10.1016/j.jceh.2014.07.006] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 07/08/2014] [Indexed: 12/12/2022] Open
Abstract
Hepatic encephalopathy (HE) is a major neurological complication of severe liver disease that presents in acute and chronic forms. While elevated brain ammonia level is known to be a major etiological factor in this disorder, recent studies have shown a significant role of neuroinflammation in the pathogenesis of both acute and chronic HE. This review summarizes the involvement of ammonia in the activation of microglia, as well as the means by which ammonia triggers inflammatory responses in these cells. Additionally, the role of ammonia in stimulating inflammatory events in brain endothelial cells (ECs), likely through the activation of the toll-like receptor-4 and the associated production of cytokines, as well as the stimulation of various inflammatory factors in ECs and in astrocytes, are discussed. This review also summarizes the inflammatory mechanisms by which activation of ECs and microglia impact on astrocytes leading to their dysfunction, ultimately contributing to astrocyte swelling/brain edema in acute HE. The role of microglial activation and its contribution to the progression of neurobehavioral abnormalities in chronic HE are also briefly presented. We posit that a better understanding of the inflammatory events associated with acute and chronic HE will uncover novel therapeutic targets useful in the treatment of patients afflicted with HE.
Collapse
Key Words
- AHE, acute hepatic encephalopathy
- ALF, acute liver failure
- BBB, blood–brain barrier
- BDL, bile duct ligation
- COX2, cyclooxygenase-2
- ECs, endothelial cells
- FHF, fulminant hepatic failure
- HE, hepatic encephalopathy
- HO, hemoxygenase
- IL, interleukin
- LPS, lipopolysaccharide
- MAPK, mitogen-activated protein kinases
- NF-κB, nuclear factor-kappaB
- NOX, NADPH oxidase
- ONS, oxidative/nitrative stress
- PLA2, phospholipase-A2
- RONS, reactive oxygen and nitrogen species
- TLR, Toll-like receptor
- TNF-α, tumor necrosis factor-alpha
- Tg, transgenic
- WT, wild type
- ammonia
- cNOS, constitutive nitric oxide synthase
- hepatic encephalopathy
- iNOS, inducible nitric oxide synthase
- neuroinflammation
Collapse
Affiliation(s)
| | | | - Michael D. Norenberg
- Laboratory of Neuropathology, Veterans Affairs Medical Center, Miami, FL, USA,Department of Pathology, University of Miami School of Medicine, Miami, FL, USA,Biochemistry & Molecular Biology, University of Miami School of Medicine, Miami, FL, USA,Address for correspondence: Michael D. Norenberg, Department of Pathology (D-33), PO Box 016960, University of Miami School of Medicine, Miami, FL 33101. Tel.: +1 305 575 7000x4018.
| |
Collapse
|
26
|
Hepatic encephalopathy in patients with acute decompensation of cirrhosis and acute-on-chronic liver failure. J Hepatol 2015; 62:437-47. [PMID: 25218789 DOI: 10.1016/j.jhep.2014.09.005] [Citation(s) in RCA: 152] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 08/29/2014] [Accepted: 09/02/2014] [Indexed: 12/12/2022]
Abstract
Hepatic encephalopathy in a hospitalized cirrhotic patient is associated with a high mortality rate and its presence adds further to the mortality of patients with acute-on-chronic liver failure (ACLF). The exact pathophysiological mechanisms of HE in this group of patients are unclear but hyperammonemia, systemic inflammation (including sepsis, bacterial translocation, and insulin resistance) and oxidative stress, modulated by glutaminase gene alteration, remain as key factors. Moreover, alcohol misuse, hyponatremia, renal insufficiency, and microbiota are actively explored. HE diagnosis requires exclusion of other causes of neurological, metabolic and psychiatric dysfunction. Hospitalization in the ICU should be considered in every patient with overt HE, but particularly if this is associated with ACLF. Precipitating factors should be identified and treated as required. Evidence-based specific management options are limited to bowel cleansing and non-absorbable antibiotics. Ammonia lowering drugs, such as glycerol phenylbutyrate and ornithine phenylacetate show promise but are still in clinical trials. Albumin dialysis may be useful in refractory cases. Antibiotics, prebiotics, and treatment of diabetes reduce systemic inflammation. Where possible and not contraindicated, large portal-systemic shunts may be embolized but liver transplantation is the most definitive step in the management of HE in this setting. HE in patients with ACLF appears to be clinically and pathophysiologically distinct from that of acute decompensation and requires further studies and characterization.
Collapse
|
27
|
Amara S, Lopez K, Banan B, Brown SK, Whalen M, Myles E, Ivy MT, Johnson T, Schey KL, Tiriveedhi V. Synergistic effect of pro-inflammatory TNFα and IL-17 in periostin mediated collagen deposition: potential role in liver fibrosis. Mol Immunol 2014; 64:26-35. [PMID: 25467797 DOI: 10.1016/j.molimm.2014.10.021] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 10/19/2014] [Accepted: 10/25/2014] [Indexed: 12/21/2022]
Abstract
BACKGROUND The pro-inflammatory cytokines, tumor necrosis factor (TNF)-α, and interleukin (IL)-17, have been implicated in the pathogenesis of liver fibrosis. In this study, we investigated the role of TNFα and IL-17 toward induction of profibrotic factor, periostin. METHODS HepG2 cells were cultured and treated with inflammatory cytokines, TNFα and IL-17. Computational promoter sequence analysis of the periostin promoter was performed to define the putative binding sites for transcription factors. Transcription factors were analyzed by Western blot and Chromatin Immunoprecipitation. Periostin and transcription factor expression analysis was performed by RT-PCR, Western blot, and fluorescence microscopy. Type I collagen expression from fibroblast cultures was analyzed by Western blot and Sircol soluble collagen assay. RESULTS Activation of HepG2 Cells with TNFα and IL-17 enhanced the expression of periostin (3.5 and 4.4 fold, respectively p<0.05) compared to untreated cells. However, combined treatment with both TNFα and IL-17 at similar concentration demonstrated a 13.3 fold increase in periostin (p<0.01), thus suggesting a synergistic role of these cytokines. Periostin promoter analysis and specific siRNA knock-down revealed that TNFα induces periostin through cJun, while IL-17 induced periostin via STAT-3 signaling mechanisms. Treatment of the supernatant from the cytokine activated HepG2 cells on fibroblast cultures induced enhanced expression of type I collagen (>9.1 fold, p<0.01), indicative of a direct fibrogenic effect of TNFα and IL-17. CONCLUSION TNFα and IL-17 induced fibrogenesis through cJun and STAT-3 mediated expression of profibrotic biomarker, periostin. Therefore, periostin might serve as a novel biomarker in early diagnosis of liver fibrosis.
Collapse
Affiliation(s)
- Suneetha Amara
- Department of Medicine, Mercy Hospital, St Louis, MO, USA
| | - Karina Lopez
- Department of Biological Sciences, Tennessee State University, Nashville, TN, USA
| | - Babak Banan
- Department of Surgery, Washington University School of Medicine, St Louis, MO, USA
| | - Sade-Kemi Brown
- Department of Biological Sciences, Tennessee State University, Nashville, TN, USA
| | - Margaret Whalen
- Department of Chemistry, Tennessee State University, Nashville, TN, USA
| | - Elbert Myles
- Department of Biological Sciences, Tennessee State University, Nashville, TN, USA
| | - Michael T Ivy
- Department of Biological Sciences, Tennessee State University, Nashville, TN, USA
| | - Terrance Johnson
- Department of Biological Sciences, Tennessee State University, Nashville, TN, USA
| | - Kevin L Schey
- Department of Biochemistry, Mass Spectrometry and Proteomics Research Core, Vanderbilt University, Nashville, TN, USA
| | | |
Collapse
|
28
|
Tivers MS, Handel I, Gow AG, Lipscomb VJ, Jalan R, Mellanby RJ. Hyperammonemia and systemic inflammatory response syndrome predicts presence of hepatic encephalopathy in dogs with congenital portosystemic shunts. PLoS One 2014; 9:e82303. [PMID: 24392080 PMCID: PMC3879253 DOI: 10.1371/journal.pone.0082303] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 10/22/2013] [Indexed: 12/29/2022] Open
Abstract
Hepatic encephalopathy (HE) is an important cause of morbidity and mortality in patients with liver disease. The pathogenesis of he is incompletely understood although ammonia and inflammatory cytokines have been implicated as key mediators. To facilitate further mechanistic understanding of the pathogenesis of HE, a large number of animal models have been developed which often involve the surgical creation of an anastomosis between the hepatic portal vein and the caudal vena cava. One of the most common congenital abnormalities in dogs is a congenital portosystemic shunt (cpss), which closely mimics these surgical experimental models of HE. Dogs with a cPSS often have clinical signs which mimic clinical signs observed in humans with HE. Our hypothesis is that the pathogenesis of HE in dogs with a cPSS is similar to humans with HE. The aim of the study was to measure a range of clinical, haematological and biochemical parameters, which have been linked to the development of HE in humans, in dogs with a cPSS and a known HE grade. One hundred and twenty dogs with a cPSS were included in the study and multiple regression analysis of clinical, haematological and biochemical variables revealed that plasma ammonia concentrations and systemic inflammatory response syndrome scores predicted the presence of HE. Our findings further support the notion that the pathogenesis of canine and human HE share many similarities and indicate that dogs with cPSS may be an informative spontaneous model of human HE. Further investigations on dogs with cPSS may allow studies on HE to be undertaken without creating surgical models of HE thereby allowing the number of large animals used in animal experimentation to be reduced.
Collapse
Affiliation(s)
- Mickey S. Tivers
- Department of Veterinary Clinical Sciences, Royal Veterinary College, Hatfield, Hertfordshire, United Kingdom
| | - Ian Handel
- Royal (Dick) School of Veterinary Studies and The Roslin Institute, The University of Edinburgh, Roslin, Midlothian, United Kingdom
| | - Adam G. Gow
- Royal (Dick) School of Veterinary Studies and The Roslin Institute, The University of Edinburgh, Roslin, Midlothian, United Kingdom
| | - Vicky J. Lipscomb
- Department of Veterinary Clinical Sciences, Royal Veterinary College, Hatfield, Hertfordshire, United Kingdom
| | - Rajiv Jalan
- UCL Institute for Liver and Digestive Health, UCL Medical School, London, United Kingdom
| | - Richard J. Mellanby
- Royal (Dick) School of Veterinary Studies and The Roslin Institute, The University of Edinburgh, Roslin, Midlothian, United Kingdom
- MRC Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
| |
Collapse
|
29
|
Abstract
Hepatic encephalopathy (HE) is a serious neuropsychiatric complication of cirrhosis in alcoholic patients that is characterized clinically by personality changes, sleep abnormalities, and impaired motor coordination, as well as cognitive dysfunction progressing to stupor and coma. Procedures used for diagnosis and grading of HE include neurologic assessment, electroencephalography, psychometric testing, and use of the critical flicker frequency test. Neuropathologically, HE in cirrhosis is principally a disorder of neuroglia characterized by Alzheimer type II astrocytosis and activation of microglia. However, thalamic and cerebellar neuronal pathologies have been noted as well as lesions to globus pallidus and substantia nigra, leading to a condition known as "parkinsonism in cirrhosis." Multiple mechanisms have been proposed to account for the pathogenesis of HE in cirrhosis, including the neurotoxic actions of ammonia and manganese (normally removed via the hepatobiliary route), impaired brain energy metabolism, central proinflammatory mechanisms, and alterations of both excitatory and inhibitory neurotransmission. Treatment of HE in cirrhosis continues to rely on ammonia-lowering strategies such as lactulose, antibiotics, probiotics and l-ornithine l-aspartate with nutritional management consisting of adequate (but not excessive) dietary protein and vitamin B1 supplements. l-DOPA may improve parkinsonian symptoms. Liver transplantation leads to recovery of central nervous system function in the majority of cases.
Collapse
Affiliation(s)
- Roger F Butterworth
- Neuroscience Research Unit, Hôpital St-Luc (CHUM), University of Montreal, Montreal, Qc., Canada.
| |
Collapse
|
30
|
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.
Collapse
|
31
|
Luo M, Li L, Yang EN, Dai CY, Liang SR, Cao WK. Correlation between interleukin-6 and ammonia in patients with overt hepatic encephalopathy due to cirrhosis. Clin Res Hepatol Gastroenterol 2013; 37:384-90. [PMID: 23084463 DOI: 10.1016/j.clinre.2012.08.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2012] [Revised: 07/12/2012] [Accepted: 08/08/2012] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Previous studies have shown that elevated serum levels of interleukin-6 (IL-6) correlate with the severity of overt hepatic encephalopathy (OHE) in cirrhotic patients. However, the correlation between serum IL-6 levels and plasma ammonia levels in these patients remains unclear. Therefore, the present study investigated this correlation between both variables in cirrhotic patients with OHE. METHODS Fifty-five cirrhotic patients with various grades of OHE, 29 cirrhotic patients without OHE, and 30 healthy controls were recruited. Concentrations of plasma ammonia and serum IL-6 were simultaneously measured. RESULTS In cirrhotic patients with OHE, the severity of OHE, represented by the West Haven criteria, correlated with serum IL-6 levels (r=0.43, P<0.05) and plasma ammonia levels (r=0.59, P<0.05). IL-6 and ammonia were found to be significant independent predictors of OHE severity (P<0.05 for both variables). Furthermore, the severity of liver cirrhosis, determined by Child-Pugh scores, correlated with serum IL-6 levels (r=0.45, P<0.05) and plasma ammonia levels (r=0.68, P<0.05) in these patients. Moreover, there was a significant positive correlation between serum IL-6 levels and plasma ammonia levels (r=0.58, P<0.05) in cirrhotic patients with OHE, but not in patients without OHE (r=0.42, P>0.05) or healthy controls (r=0.27, P>0.05). The correlation between IL-6 and ammonia was independent of infectious precipitating factors. CONCLUSIONS The results of the present study suggest that IL-6 might be involved in the mechanism by which ammonia contributes to the pathogenesis of OHE. There is also evidence of a potential synergistic interaction between proinflammatory cytokines and ammonia in the pathogenesis of OHE.
Collapse
Affiliation(s)
- Ming Luo
- Graduate School, Tianjin Medical University, No. 81 mailbox, 22, Qixiangtai Road, Heping District, 300070 Tianjin, China.
| | | | | | | | | | | |
Collapse
|
32
|
Popović Dragonjić L, Krtinić D, Dragonjić I. RECENT THEORIES OF PATHOGENESIS OF HEPATIC ENCEPHALOPATHY IN HEPATITIS C VIRAL INFECTION. ACTA MEDICA MEDIANAE 2013. [DOI: 10.5633/amm.2013.0208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
|
33
|
Bees' honey attenuation of metanil-yellow-induced hepatotoxicity in rats. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2013; 2013:614580. [PMID: 23818929 PMCID: PMC3684022 DOI: 10.1155/2013/614580] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 05/12/2013] [Indexed: 01/20/2023]
Abstract
The present study aims to investigate the protective effect of bees' honey against metanil-yellow-induced hepatotoxicity in rats. Rats were divided into 7 groups: control group; three groups treated with 50, 100, and 200 mg/kg metanil yellow, and three groups treated with metanil yellow plus 2.5 mg · kg(-1) · day(-1) bees' honey for 8 weeks. The obtained data showed that the antioxidant/anti-inflammatory activity of bees' honey reduced the oxidative stress in the liver tissue and downregulated the inflammatory markers. In addition, the elevated levels of AGE and the activated NF- κ B in the metanil-yellow-treated animals were significantly attenuated. Moreover, the levels of TNF- α and IL-1 β were significantly attenuated as a result of bees' honey administration. Furthermore, the histopathological examination of the liver showed that bees' honey reduced fatty degeneration, cytoplasmic vacuolization, and necrosis in metanil-yellow-treated rats. In conclusion, the obtained data suggest that bees' honey has hepatoprotective effect on acute liver injuries induced by metanil-yellow in vivo, and the results suggested that the effect of bees' honey against metanil yellow-induced liver damage is related to its antioxidant/anti-inflammatory properties which attenuate the activation of NF- κ B and its controlled genes like TNF- α and IL-1 β .
Collapse
|
34
|
Bémeur C, Butterworth RF. Liver-brain proinflammatory signalling in acute liver failure: role in the pathogenesis of hepatic encephalopathy and brain edema. Metab Brain Dis 2013; 28:145-50. [PMID: 23212479 DOI: 10.1007/s11011-012-9361-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 11/05/2012] [Indexed: 12/12/2022]
Abstract
A robust neuroinflammatory response characterized by microglial activation and increased brain production of pro-inflammatory cytokines is common in acute liver failure (ALF). Mechanisms proposed to explain the neuroinflammatory response in ALF include direct effects of systemically-derived proinflammatory cytokines and the effects of brain lactate accumulation on pro-inflammatory cytokine release from activated microglia. Cell culture studies reveal a positive synergistic effect of ammonia and pro-inflammatory cytokines on the expression of proteins involved in glutamate homeostasis and in oxidative/nitrosative stress. Proinflammatory cytokines have the capacity to alter blood-brain barrier (BBB) integrity and preliminary studies suggest that the presence of infection in ALF results in rupture of the BBB and vasogenic brain edema. Treatments currently under investigation that are effective in prevention of encephalopathy and brain edema in ALF which are aimed at reduction of neuroinflammation in ALF include mild hypothermia, albumin dialysis systems, N-acetyl cysteine and the antibiotic minocycline with potent anti-inflammatory actions that are distinct from its anti-microbial properties.
Collapse
Affiliation(s)
- Chantal Bémeur
- Département de nutrition, Faculté de médecine, Université de Montréal, Montréal, QC, Canada
| | | |
Collapse
|
35
|
Jain L, Sharma BC, Sharma P, Srivastava S, Agrawal A, Sarin SK. Serum endotoxin and inflammatory mediators in patients with cirrhosis and hepatic encephalopathy. Dig Liver Dis 2012; 44:1027-31. [PMID: 22883217 DOI: 10.1016/j.dld.2012.07.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 06/24/2012] [Accepted: 07/05/2012] [Indexed: 12/11/2022]
Abstract
BACKGROUND Recent observations suggest that inflammatory response may be important in the pathogenesis of hepatic encephalopathy. The aim of the study was to measure arterial ammonia, tumour necrosis factor-alpha, Interleukin-6, Interleukin-18, and serum endotoxin levels and their correlation with different grades of hepatic encephalopathy. METHODS 120 patients with cirrhosis were enrolled: 20 patients each of cirrhosis with grades I, II, III and IV hepatic encephalopathy, cirrhosis with and without minimal hepatic encephalopathy and healthy controls were tested for arterial ammonia, tumour necrosis factor-alpha, Interleukin-6, Interleukin-18 and serum endotoxin levels. RESULTS Median arterial ammonia, tumour necrosis factor-alpha, Interleukin-6, Interleukin-18 and serum endotoxin levels were significantly higher in patient with hepatic encephalopathy and minimal hepatic encephalopathy as compared to patients without minimal hepatic encephalopathy and healthy controls. Arterial ammonia (r = 0.72, p = 0.03), tumour necrosis factor alpha (r = 0.87, p = 0.02), Interleukin-6 (r = 0.50, p = 0.05), Interleukin-18 (r = 0.76, p = 0.02) and serum endotoxin (r = 0.91, p = 0.01) correlated with higher grades of hepatic encephalopathy. CONCLUSION In hepatic encephalopathy arterial ammonia, inflammatory mediators, and serum endotoxin are elevated and correlate with encephalopathy grade.
Collapse
Affiliation(s)
- Lokesh Jain
- Department of Gastroenterology, GB Pant Hospital, New Delhi, India
| | | | | | | | | | | |
Collapse
|
36
|
Chastre A, Bélanger M, Beauchesne E, Nguyen BN, Desjardins P, Butterworth RF. Inflammatory cascades driven by tumor necrosis factor-alpha play a major role in the progression of acute liver failure and its neurological complications. PLoS One 2012; 7:e49670. [PMID: 23166746 PMCID: PMC3499491 DOI: 10.1371/journal.pone.0049670] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 10/12/2012] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND/AIMS Acute liver failure (ALF) due to ischemic or toxic liver injury is a clinical condition that results from massive loss of hepatocytes and may lead to hepatic encephalopathy (HE), a serious neuropsychiatric complication. Although increased expression of tumor necrosis factor-alpha (TNF-α) in liver, plasma and brain has been observed, conflicting results exist concerning its roles in drug-induced liver injury and on the progression of HE. The present study aimed to investigate the therapeutic value of etanercept, a TNF-α neutralizing molecule, on the progression of liver injury and HE in mice with ALF resulting from azoxymethane (AOM) hepatotoxicity. METHODS/PRINCIPAL FINDINGS Mice were administered saline or etanercept (10 mg/kg; i.p.) 30 minutes prior to, or up to 6 h after AOM. Etanercept-treated ALF mice were sacrificed in parallel with vehicle-treated comatose ALF mice and controls. AOM induced severe hepatic necrosis, leading to HE, and etanercept administered prior or up to 3 h after AOM significantly delayed the onset of coma stages of HE. Etanercept pretreatment attenuated AOM-induced liver injury, as assessed by histological examination, plasma ammonia and transaminase levels, and by hepatic glutathione content. Peripheral inflammation was significantly reduced by etanercept as shown by decreased plasma IL-6 (4.1-fold; p<0.001) and CD40L levels (3.7-fold; p<0.001) compared to saline-treated ALF mice. Etanercept also decreased IL-6 levels in brain (1.2-fold; p<0.05), attenuated microglial activation (assessed by OX-42 immunoreactivity), and increased brain glutathione concentrations. CONCLUSIONS These results indicate that systemic sequestration of TNF-α attenuates both peripheral and cerebral inflammation leading to delayed progression of liver disease and HE in mice with ALF due to toxic liver injury. These results suggest that etanercept may provide a novel therapeutic approach for the management of ALF patients awaiting liver transplantation.
Collapse
Affiliation(s)
- Anne Chastre
- Neuroscience Research Unit, Hôpital Saint-Luc, CRCHUM, Montreal, Canada
| | - Mireille Bélanger
- Neuroscience Research Unit, Hôpital Saint-Luc, CRCHUM, Montreal, Canada
| | | | - Bich N. Nguyen
- Département de pathologie, Hôpital Saint-Luc, CHUM, Montreal, Canada
| | - Paul Desjardins
- Neuroscience Research Unit, Hôpital Saint-Luc, CRCHUM, Montreal, Canada
| | - Roger F. Butterworth
- Neuroscience Research Unit, Hôpital Saint-Luc, CRCHUM, Montreal, Canada
- * E-mail:
| |
Collapse
|
37
|
Back A, Tupper KY, Bai T, Chiranand P, Goldenberg FD, Frank JI, Brorson JR. Ammonia-induced brain swelling and neurotoxicity in an organotypic slice model. Neurol Res 2012; 33:1100-8. [PMID: 22196764 DOI: 10.1179/1743132811y.0000000046] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
OBJECTIVES Acute liver failure (ALF) produces cerebral dysfunction and edema, mediated in part by elevated ammonia concentrations, often leading to coma and death. The pathophysiology of cerebral edema in ALF is incompletely understood. In vitro models of the cerebral effects of ALF have predominately consisted of dissociated astrocyte cultures or acute brain slices. We describe a stable long-term culture model incorporating both neural and glial elements in a three-dimensional tissue structure offering significant advantages to the study of astrocytic-neuronal interactions in the pathophysiology of cerebral edema and dysfunction in ALF. METHODS We utilized chronic organotypic slice cultures from mouse forebrain, applying ammonium acetate in iso-osmolar fashion for 72 hours. Imaging of slice thickness to assess for tissue swelling was accomplished in living slices with optical coherence tomography, and confocal microscopy of fluorescence immunochemical and histochemical staining served to assess astrocyte and neuronal numbers, morphology, and volume in the fixed brain slices. RESULTS Ammonia exposure at 1-10 mM produced swelling of immunochemically identified astrocytes, and at 10 mM resulted in macroscopic tissue swelling, with slice thickness increasing by about 30%. Astrocytes were unchanged in number. In contrast, 10 mM ammonia treatment severely disrupted neuronal morphology and reduced neuronal survival at 72 hours by one-half. DISCUSSION Elevated ammonia produces astrocytic swelling, tissue swelling, and neuronal toxicity in cerebral tissues. Ammonia-treated organotypic brain slice cultures provide an In vitro model of cerebral effects of conditions relevant to ALF, applicable to pathophysiological investigations.
Collapse
Affiliation(s)
- Adam Back
- Department of Surgery, The University of Chicago,IL 60637, USA
| | | | | | | | | | | | | |
Collapse
|
38
|
de Freitas Souza BS, Nascimento RC, de Oliveira SA, Vasconcelos JF, Kaneto CM, de Carvalho LFPP, Ribeiro-Dos-Santos R, Soares MBP, de Freitas LAR. Transplantation of bone marrow cells decreases tumor necrosis factor-α production and blood-brain barrier permeability and improves survival in a mouse model of acetaminophen-induced acute liver disease. Cytotherapy 2012; 14:1011-21. [PMID: 22809224 DOI: 10.3109/14653249.2012.684445] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND AIMS Acute liver failure (ALF), although rare, remains a rapidly progressive and frequently fatal condition. Acetaminophen (APAP) poisoning induces a massive hepatic necrosis and often leads to death as a result of cerebral edema. Cell-based therapies are currently being investigated for liver injuries. We evaluated the therapeutic potential of transplantation of bone marrow mononuclear cells (BMC) in a mouse model of acute liver injury. METHODS ALF was induced in C57Bl/6 mice submitted to an alcoholic diet followed by fasting and injection of APAP. Mice were transplanted with 10(7) BMC obtained from enhanced green fluorescent protein (GFP) transgenic mice. RESULTS BMC transplantation caused a significant reduction in APAP-induced mortality. However, no significant differences in serum aminotransferase concentrations, extension of liver necrosis, number of inflammatory cells and levels of cytokines in the liver were found when BMC- and saline-injected groups were compared. Moreover, recruitment of transplanted cells to the liver was very low and no donor-derived hepatocytes were observed. Mice submitted to BMC therapy had some protection against disruption of the blood-brain barrier, despite their hyperammonemia, and serum metalloproteinase (MMP)-9 activity similar to the saline-injected group. Tumor necrosis factor (TNF)-α concentrations were decreased in the serum of BMC-treated mice. This reduction was associated with an early increase in interleukin (IL)-10 mRNA expression in the spleen and bone marrow after BMC treatment. CONCLUSIONS BMC transplantation protects mice submitted to high doses of APAP and is a potential candidate for ALF treatment, probably via an immunomodulatory effect on TNF-α production.
Collapse
Affiliation(s)
- Bruno Solano de Freitas Souza
- Laboratório de Engenharia Tecidual e Imunofarmacologia, Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, BA, Brazil
| | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Butterworth RF. Reprint of: Neuroinflammation in acute liver failure: mechanisms and novel therapeutic targets. Neurochem Int 2012; 60:715-22. [PMID: 22504574 DOI: 10.1016/j.neuint.2012.03.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Revised: 07/20/2011] [Accepted: 07/28/2011] [Indexed: 01/31/2023]
Abstract
It is increasingly evident that neuroinflammatory mechanisms are implicated in the pathogenesis of the central nervous system (CNS) complications (intracranial hypertension, brain herniation) of acute liver failure (ALF). Neuroinflammation in ALF is characterized by microglial activation and arterio-venous difference studies as well as studies of gene expression confirm local brain production and release of proinflammatory cytokines including TNF-α and the interleukins IL-1β and IL-6. Although the precise nature of the glial cell responsible for brain cytokine synthesis is not yet established, evidence to date supports a role for both astrocytes and microglia. The neuroinflammatory response in ALF progresses in parallel with the progression of hepatic encephalopathy (HE) and with the severity of brain edema (astrocyte swelling). Mechanisms responsible for the relaying of signals from the failing liver to the brain include transduction of systemic proinflammatory signals as well as the effects of increased brain lactate leading to increased release of cytokines from both astrocytes and microglia. There is evidence in support of a synergistic effect of proinflammatory cytokines and ammonia in the pathogenesis of HE and brain edema in ALF. Therapeutic implications of the findings of a neuroinflammatory response in ALF are multiple. Removal of both ammonia and proinflammatory cytokines is possible using antibiotics or albumen dialysis. Mild hypothermia reduces brain ammonia transfer, brain lactate production, microglial activation and proinflammatory cytokine production resulting in reduced brain edema and intracranial pressure in ALF. N-Acetylcysteine acts as both an antioxidant and anti-inflammatory agent at both peripheral and central sites of action independently resulting in slowing of HE progression and prevention of brain edema. Novel treatments that directly target the neuroinflammatory response in ALF include the use of etanercept, a TNF-α neutralizing molecule and minocycline, an agent with potent inhibitory actions on microglial activation that are independent of its antimicrobial properties; both agents have been shown to be effective in reducing neuroinflammation and in preventing the CNS complications of ALF. Translation of these findings to the clinic has the potential to provide rational targeted approaches to the prevention and treatment of these complications in the near future.
Collapse
Affiliation(s)
- Roger F Butterworth
- Neuroscience Research Unit, Saint-Luc Hospital, CHUM, University of Montreal, Montreal, Quebec, Canada.
| |
Collapse
|
40
|
Rizvi M, Azam M, Ajmal MR, Shukla I, Malik A. Prevalence of leptospira in acute hepatitis syndrome and assessment of IL-8 and TNF-alpha level in leptospiral hepatitis. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2012; 105:499-506. [PMID: 22185944 DOI: 10.1179/1364859411y.0000000041] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
To study the prevalence of leptospira in acute hepatitis syndrome and to assess interleukin (IL)-8 and tumour necrosis factor (TNF)-alpha levels in the pathogenesis of hepatitis due to leptospiral infection. Two hundred and forty-seven consecutive cases with symptoms of acute hepatitis and 30 healthy controls were enrolled in the study and detailed clinical history was elicited from them. Enzyme-linked immunosorbent assays (ELISAs) for HAV, HBV, HCV and HEV were performed to rule out common viral aetiology of hepatitis. IgM antibodies to leptospira were detected by ELISA. IL-8 and TNF-alpha levels were estimated in leptospira-positive cases and healthy controls by ELISA. Out of 247 cases of acute hepatitis, 46 (18.62%) were observed to be positive for IgM antibodies for leptospira. The mean age of these patients was 31.99 ± 0.28 years (25 males and 21 females; M/F ratio: 1.19:1). The mean ALT, AST and ASP were raised in the majority of patients. IL-8 was found to be elevated (130.81 pg/ml) in a large majority of cases 41/46, 89.1% (P < 0.001). Patients with more severe symptoms were associated with higher levels of IL-8. One mortality was observed due to leptospira. Unpredictably, TNF-alpha level was largely suppressed (45.63 pg/ml) in most of the leptospira-positive patients in comparison with healthy controls. Leptospira-induced hepatitis should be actively looked for in patients negative for A-E viral hepatitis. IL-8 appears to play an important role in the pathogenesis of leptospiral hepatitis. High TNF-alpha should alert clinicians for aggressive in hospital management of patients.
Collapse
Affiliation(s)
- M Rizvi
- Department of Microbiology, Faculty of Medicine, J.N. Medical College, Aligarh Muslim University, Aligarh 202002, India.
| | | | | | | | | |
Collapse
|
41
|
Wilkinson DJ, Smeeton NJ, Castle PC, Watt PW. Absence of neuropsychological impairment in hyperammonaemia in healthy young adults; possible synergism in development of hepatic encephalopathy (HE) symptoms? Metab Brain Dis 2011; 26:203-12. [PMID: 21773808 DOI: 10.1007/s11011-011-9251-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Accepted: 07/04/2011] [Indexed: 12/16/2022]
Abstract
The aetiology of minimal hepatic encephalopathy (mHE) remains unclear. It is generally accepted that hyperammonaemia plays a major role, however there are a multitude of metabolic perturbations present. To determine the contribution of hyperammonaemia to mHE symptom development, ten healthy males (Age:25 ± 5 yrs, BM:76.3 ± 7.1 kg, Height:178.6 ± 4.5 cm, mean ± SD) received two 4 h intravenous infusions of either a 2% ammonium chloride solution (AMM) or a placebo (PLA;0.9% sodium chloride) using a double blind cross-over design. Sensations of fatigue were measured at baseline, 2 and 4 h using the Multidimensional Fatigue Symptom Inventory-Short Form (MFSI-SF) questionnaire. Learning & memory, motor control and cognition were assessed using Rey's Auditory Verbal Learning Test (AVL), Continuous Compensatory Tracking (COMPTRACK) Task and Inhibitory Control Test (ICT) respectively. Arterialised venous blood samples were collected every hour, and analysed for ammonia concentration. There was a significantly higher plasma ammonia concentration in the AMM trial than the PLA trial at every time point during the infusion, peaking at 2 h (57 ± 4 μmol/L PLA, 225 ± 14 μmol/L AMM; p < 0.05). At 2 h there were significantly higher sensations of general fatigue (Z = -2.527, p = 0.008, 2 tailed) and physical fatigue (Z = -2.156, p = 0.027, 2 tailed), and lower sensations of vigour (Z = -2.456, p = 0.012, 2 tailed) for the AMM trial. There were no significant effects on the performance of the psychological tasks. These results demonstrate that hyperammonaemia in the absence of other complications induces significant sensations of fatigue but does not cause the typically observed performance impairment in individuals with mHE. Supporting the hypothesis for synergism between ammonia and other co-factors in mHE.
Collapse
Affiliation(s)
- Daniel J Wilkinson
- Department of Sport and Exercise Science, Chelsea School, University of Brighton, 30 Carlisle Road, Eastbourne BN20 7SN, UK.
| | | | | | | |
Collapse
|
42
|
Butterworth RF. Neuroinflammation in acute liver failure: mechanisms and novel therapeutic targets. Neurochem Int 2011; 59:830-6. [PMID: 21864609 DOI: 10.1016/j.neuint.2011.07.014] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Revised: 07/20/2011] [Accepted: 07/28/2011] [Indexed: 12/21/2022]
Abstract
It is increasingly evident that neuroinflammatory mechanisms are implicated in the pathogenesis of the central nervous system (CNS) complications (intracranial hypertension, brain herniation) of acute liver failure (ALF). Neuroinflammation in ALF is characterized by microglial activation and arterio-venous difference studies as well as studies of gene expression confirm local brain production and release of proinflammatory cytokines including TNF-α and the interleukins IL-1β and IL-6. Although the precise nature of the glial cell responsible for brain cytokine synthesis is not yet established, evidence to date supports a role for both astrocytes and microglia. The neuroinflammatory response in ALF progresses in parallel with the progression of hepatic encephalopathy (HE) and with the severity of brain edema (astrocyte swelling). Mechanisms responsible for the relaying of signals from the failing liver to the brain include transduction of systemic proinflammatory signals as well as the effects of increased brain lactate leading to increased release of cytokines from both astrocytes and microglia. There is evidence in support of a synergistic effect of proinflammatory cytokines and ammonia in the pathogenesis of HE and brain edema in ALF. Therapeutic implications of the findings of a neuroinflammatory response in ALF are multiple. Removal of both ammonia and proinflammatory cytokines is possible using antibiotics or albumen dialysis. Mild hypothermia reduces brain ammonia transfer, brain lactate production, microglial activation and proinflammatory cytokine production resulting in reduced brain edema and intracranial pressure in ALF. N-Acetylcysteine acts as both an antioxidant and anti-inflammatory agent at both peripheral and central sites of action independently resulting in slowing of HE progression and prevention of brain edema. Novel treatments that directly target the neuroinflammatory response in ALF include the use of etanercept, a TNF-α neutralizing molecule and minocycline, an agent with potent inhibitory actions on microglial activation that are independent of its antimicrobial properties; both agents have been shown to be effective in reducing neuroinflammation and in preventing the CNS complications of ALF. Translation of these findings to the clinic has the potential to provide rational targeted approaches to the prevention and treatment of these complications in the near future.
Collapse
Affiliation(s)
- Roger F Butterworth
- Neuroscience Research Unit, Saint-Luc Hospital (CHUM), University of Montreal, Montreal, Quebec, Canada.
| |
Collapse
|
43
|
Tumor necrosis factor-α affects blood-brain barrier permeability in acetaminophen-induced acute liver failure. Eur J Gastroenterol Hepatol 2011; 23:552-8. [PMID: 21593677 DOI: 10.1097/meg.0b013e3283470212] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVES Cerebral edema is a major cause of death during acute liver failure (ALF), but the exact mechanism of this condition is still not entirely clear. The aim of this study was to investigate the role of tumor necrosis factor α (TNFα) in changing the permeability of the blood-brain barrier (BBB) during acetaminophen (APAP)-induced ALF. MATERIALS AND METHODS ALF animal models were generated by administering APAP. Anti-TNFα-IgG was intravenously injected (100 μg/mouse) 2 h after administration of APAP. We investigated BBB permeability with Evans blue staining, and structure with electron microscopy. RESULTS BBB permeability increased in APAP-induced ALF mice and correlated with elevated serum TNFα levels. Electron microscopy of mouse brain tissues revealed tight junction (TJ) disruptions and endothelial cell shrinkage, as well as increased vesicles and vacuoles. In addition, the expression of the TJ-associated protein, occludin, was significantly decreased in APAP-induced ALF mice. Changes in BBB permeability and occludin expression could be prevented by administering anti-TNFα-IgG 2 h after APAP challenge. CONCLUSION TNFα plays a critical role in the development of brain edema in APAP-induced ALF. Increased BBB permeability may be due to the loss of the TJ-associated protein occludin.
Collapse
|
44
|
Goralczyk AD, Meier V, Ramadori G, Obed A, Lorf T. Acute paranoid psychosis as sole clinical presentation of hepatic artery thrombosis after living donor liver transplantation. BMC Surg 2010; 10:7. [PMID: 20175918 PMCID: PMC2836309 DOI: 10.1186/1471-2482-10-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Accepted: 02/22/2010] [Indexed: 11/10/2022] Open
Abstract
Background Hepatic artery thrombosis is a devastating complication after orthotopic liver transplantation often requiring revascularization or re-transplantation. It is associated with considerably increased morbidity and mortality. Acute cognitive dysfunction such as delirium or acute psychosis may occur after major surgery and may be associated with the advent of surgical complications. Case presentation Here we describe a case of hepatic artery thrombosis after living-donor liver transplantation which was not preceded by signs of liver failure but rather by an episode of acute psychosis. After re-transplantation the patient recovered without sequelae. Conclusion This case highlights the need to remain cautious when psychiatric disorders occur in patients after liver transplantation. The diagnostic procedures should not be restricted to medical or neurological causes of psychosis alone but should also focus vascular complications related to orthotopic liver transplantation.
Collapse
Affiliation(s)
- Armin D Goralczyk
- Department of General and Visceral Surgery, University Medical Center Göttingen, Göttingen, Germany.
| | | | | | | | | |
Collapse
|
45
|
Gow A, Marques A, Yool D, Duncan A, Mellanby R. Whole Blood Manganese Concentrations in Dogs with Congenital Portosystemic Shunts. J Vet Intern Med 2010; 24:90-6. [DOI: 10.1111/j.1939-1676.2009.0408.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
|
46
|
Focosi D, Pelosini M, Palla P, Galimberti S, Caracciolo F, Benedetti E, Papineschi F, Petrini M. Hypercytokinemia-induced metabolic encephalopathy in a multiple myeloma patient on hemodialysis undergoing autologous stem cell transplantation: clinical response after plasma exchange. Transpl Immunol 2009; 21:240-3. [PMID: 19539028 DOI: 10.1016/j.trim.2009.06.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2009] [Revised: 06/02/2009] [Accepted: 06/04/2009] [Indexed: 01/20/2023]
Abstract
We report here a 50-years old female with multiple myeloma-associated chronic renal failure who underwent high-dose chemotherapy supported by autologous hematopoietic stem cell transplantation. She developed progressive encephalopathy on day 5 progressing to coma despite hemodialysis and no obvious organ failure. She finally recovered after a single 1-liter plasma exchange. The final diagnosis was metabolic encephalopathy due to hypercytokinemia, particularly high serum TNF levels. We discuss here the pathogenesis and raise an alert for monitoring cytokine levels in patients with renal failure undergoing high-dose chemotherapy.
Collapse
Affiliation(s)
- Daniele Focosi
- Division of Hematology, Department of Oncology, Transplants and Advances in Medicine, University of Pisa, Italy.
| | | | | | | | | | | | | | | |
Collapse
|
47
|
Abstract
Hyperammonia theory has been thought as a most feasible mechanism of hepatic encephalopathy following liver injury. Astroglial swelling was reckoned as pathological basis of hepatic encephalopathy. Many assumed mechanisms include oxidative stress activation, mitochondrial permeability transition and glutamine theory, by which ammonia acts on astroglial swelling. Cytokins have influence on the development of hepatic encephalopathy. There are mutual effects of both ammonia and cytokines inducing hepatic encephalopathy.
Collapse
|
48
|
Cerebral microglia recruit monocytes into the brain in response to tumor necrosis factoralpha signaling during peripheral organ inflammation. J Neurosci 2009; 29:2089-102. [PMID: 19228962 DOI: 10.1523/jneurosci.3567-08.2009] [Citation(s) in RCA: 488] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
In inflammatory diseases occurring outside the CNS, communication between the periphery and the brain via humoral and/or neural routes results in central neural changes and associated behavioral alterations. We have recently identified another immune-to-CNS communication pathway in the setting of organ-centered peripheral inflammation: namely, the entrance of immune cells into the brain. In our current study, using a mouse model of inflammatory liver injury, we have confirmed the significant infiltration of activated monocytes into the brain in mice with hepatic inflammation and have defined the mechanism that mediates this trafficking of monocytes. Specifically, we show that in the presence of hepatic inflammation, mice demonstrate elevated cerebral monocyte chemoattractant protein (MCP)-1 levels, as well as increased numbers of circulating CCR2-expressing monocytes. Cerebral recruitment of monocytes was abolished in inflamed mice that lacked MCP-1/CCL2 or CCR2. Furthermore, in mice with hepatic inflammation, microglia were activated and produced MCP-1/CCL2 before cerebral monocyte infiltration. Moreover, peripheral tumor necrosis factor (TNF)alpha signaling was required to stimulate microglia to produce MCP-1/CCL2. TNFalpha signaling via TNF receptor 1 (TNFR1) is required for these observed effects since in TNFR1 deficient mice with hepatic inflammation, microglial expression of MCP-1/CCL2 and cerebral monocyte recruitment were both markedly inhibited, whereas there was no inhibition in TNFR2 deficient mice. Our results identify the existence of a novel immune-to-CNS communication pathway occurring in the setting of peripheral organ-centered inflammation which may have specific implications for the development of alterations in cerebral neurotransmission commonly encountered in numerous inflammatory diseases occurring outside the CNS.
Collapse
|
49
|
Yokoi T, Oda S, Shiga H, Matsuda KI, Sadahiro T, Nakamura M, Hirasawa H. Efficacy of high-flow dialysate continuous hemodiafiltration in the treatment of fulminant hepatic failure. Transfus Apher Sci 2009; 40:61-70. [DOI: 10.1016/j.transci.2008.11.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
50
|
Ahboucha S, Jiang W, Chatauret N, Mamer O, Baker GB, Butterworth RF. Indomethacin improves locomotor deficit and reduces brain concentrations of neuroinhibitory steroids in rats following portacaval anastomosis. Neurogastroenterol Motil 2008; 20:949-57. [PMID: 18482252 DOI: 10.1111/j.1365-2982.2008.01132.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Hepatic encephalopathy (HE) is a neuropsychiatric complication of both acute and chronic liver failure characterized by progressive neuronal inhibition. Some neurosteroids are potent positive allosteric modulators of the gamma-aminobutyric acid (GABA)-A receptor complex, and 'increased GABAergic tone' has been proposed to explain the neuroinhibition characteristics of HE. Brain levels of the neurosteroids pregnenolone, allopregnanolone and tetrahydrodesoxycorticosterone (THDOC) and the functional status of the GABA-A receptor complex were assessed in rats following portacaval anastomosis (PCA). Effects of indomethacin, an inhibitor of the 3alpha-hydroxysteroid dehydrogenase enzyme involved in neurosteroid synthesis, on PCA rat locomotor activity and brain neurosteroid levels were also assessed. Significant increases of the neurosteroid pregnenolone (2.6-fold), allopregnanolone (1.7-fold) and THDOC (4.7-fold) were observed in brains of PCA rats. Brain levels of these neurosteroids were in the nanomolar range, sufficient to exert positive allosteric modulatory effects at the GABA-A receptor. Indomethacin (0.1-5 mg kg(-1)) ameliorated dose-dependently the locomotor deficit of PCA rats and concomitantly normalized brain levels of allopregnanolone and THDOC. Increased brain levels of neurosteroids with positive allosteric modulatory actions at the neuronal GABA-A receptor offer a cogent explanation for the notion of 'increased GABAergic tone' in HE. Pharmacological approaches using agents that either reduce neurosteroid synthesis or modulate the neurosteroid site on GABA-A receptor could offer new therapeutic tools for the management and treatment of HE.
Collapse
Affiliation(s)
- S Ahboucha
- Neuroscience Research Unit, Université de Montréal, CHUM (Hôpital Saint-Luc), Montreal, QC, Canada.
| | | | | | | | | | | |
Collapse
|