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Pierzchala K, Hadjihambi A, Mosso J, Jalan R, Rose CF, Cudalbu C. Lessons on brain edema in HE: from cellular to animal models and clinical studies. Metab Brain Dis 2024; 39:403-437. [PMID: 37606786 PMCID: PMC10957693 DOI: 10.1007/s11011-023-01269-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 07/24/2023] [Indexed: 08/23/2023]
Abstract
Brain edema is considered as a common feature associated with hepatic encephalopathy (HE). However, its central role as cause or consequence of HE and its implication in the development of the neurological alterations linked to HE are still under debate. It is now well accepted that type A and type C HE are biologically and clinically different, leading to different manifestations of brain edema. As a result, the findings on brain edema/swelling in type C HE are variable and sometimes controversial. In the light of the changing natural history of liver disease, better description of the clinical trajectory of cirrhosis and understanding of molecular mechanisms of HE, and the role of brain edema as a central component in the pathogenesis of HE is revisited in the current review. Furthermore, this review highlights the main techniques to measure brain edema and their advantages/disadvantages together with an in-depth description of the main ex-vivo/in-vivo findings using cell cultures, animal models and humans with HE. These findings are instrumental in elucidating the role of brain edema in HE and also in designing new multimodal studies by performing in-vivo combined with ex-vivo experiments for a better characterization of brain edema longitudinally and of its role in HE, especially in type C HE where water content changes are small.
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Affiliation(s)
- Katarzyna Pierzchala
- CIBM Center for Biomedical Imaging, Lausanne, Switzerland.
- Animal Imaging and Technology, EPFL, Lausanne, Switzerland.
| | - Anna Hadjihambi
- The Roger Williams Institute of Hepatology London, Foundation for Liver Research, London, SE5 9NT, UK
- Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Jessie Mosso
- CIBM Center for Biomedical Imaging, Lausanne, Switzerland
- Animal Imaging and Technology, EPFL, Lausanne, Switzerland
- Laboratory for Functional and Metabolic Imaging (LIFMET), EPFL, Lausanne, Switzerland
| | - Rajiv Jalan
- Liver Failure Group, Institute for Liver and Digestive Health, University College London, Royal Free Campus, London, UK
- European Foundation for the Study of Chronic Liver Failure (EF Clif), Barcelona, Spain
| | - Christopher F Rose
- Hépato-Neuro Laboratory, Centre de Recherche du Centre Hospitalier de l', Université de Montréal (CRCHUM), Montreal, QC, H2X 0A9, Canada
- Department of Medicine, Faculty of Medicine, Université de Montréal, QC, Montreal, H3T 1J4, Canada
| | - Cristina Cudalbu
- CIBM Center for Biomedical Imaging, Lausanne, Switzerland.
- Animal Imaging and Technology, EPFL, Lausanne, Switzerland.
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2
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Krishnamoorthy N, Kalyan M, Hediyal TA, Anand N, Kendaganna PH, Pendyala G, Yelamanchili SV, Yang J, Chidambaram SB, Sakharkar MK, Mahalakshmi AM. Role of the Gut Bacteria-Derived Metabolite Phenylacetylglutamine in Health and Diseases. ACS OMEGA 2024; 9:3164-3172. [PMID: 38284070 PMCID: PMC10809373 DOI: 10.1021/acsomega.3c08184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 12/19/2023] [Accepted: 12/21/2023] [Indexed: 01/30/2024]
Abstract
Over the past few decades, it has been well established that gut microbiota-derived metabolites can disrupt gut function, thus resulting in an array of diseases. Notably, phenylacetylglutamine (PAGln), a bacterial derived metabolite, has recently gained attention due to its role in the initiation and progression of cardiovascular and cerebrovascular diseases. This meta-organismal metabolite PAGln is a byproduct of amino acid acetylation of its precursor phenylacetic acid (PAA) from a range of dietary sources like egg, meat, dairy products, etc. The microbiota-dependent metabolism of phenylalanine produces PAA, which is a crucial intermediate that is catalyzed by diverse microbial catalytic pathways. PAA conjugates with glutamine and glycine in the liver and kidney to predominantly form phenylacetylglutamine in humans and phenylacetylglycine in rodents. PAGln is associated with thrombosis as it enhances platelet activation mediated through the GPCRs receptors α2A, α2B, and β2 ADRs, thereby aggravating the pathological conditions. Clinical evidence suggests that elevated levels of PAGln are associated with pathology of cardiovascular, cerebrovascular, and neurological diseases. This Review further consolidates the microbial/biochemical synthesis of PAGln and discusses its role in the above pathophysiologies.
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Affiliation(s)
- Naveen
Kumar Krishnamoorthy
- Department
of Pharmacology, JSS College of Pharmacy, JSS Academy of Higher Education and Research, Mysuru 570015, India
- Centre
for Experimental Pharmacology and Toxicology, Central Animal Facility, JSS Academy of Higher Education and Research, Mysuru 570015, India
| | - Manjunath Kalyan
- Department
of Pharmacology, JSS College of Pharmacy, JSS Academy of Higher Education and Research, Mysuru 570015, India
- Centre
for Experimental Pharmacology and Toxicology, Central Animal Facility, JSS Academy of Higher Education and Research, Mysuru 570015, India
| | - Tousif Ahmed Hediyal
- Department
of Pharmacology, JSS College of Pharmacy, JSS Academy of Higher Education and Research, Mysuru 570015, India
- Centre
for Experimental Pharmacology and Toxicology, Central Animal Facility, JSS Academy of Higher Education and Research, Mysuru 570015, India
| | - Nikhilesh Anand
- Department
of Pharmacology, College of Medicine, American
University of Antigua, P. O. Box W-1451, Saint John’s, Antigua and Barbuda
| | - Pavan Heggadadevanakote Kendaganna
- Centre
for Experimental Pharmacology and Toxicology, Central Animal Facility, JSS Academy of Higher Education and Research, Mysuru 570015, India
| | - Gurudutt Pendyala
- Department
of Anesthesiology, University of Nebraska
Medical Center (UNMC), Omaha, Nebraska 68198, United States
- Department
of Genetics, Cell Biology, and Anatomy, UNMC, Omaha, Nebraska 68198, United States
- Child Health
Research Institute, UNMC, Omaha, Nebraska 68198, United States
- National
Strategic Research Institute, UNMC, Omaha, Nebraska 68198, United States
| | - Sowmya V. Yelamanchili
- Department
of Anesthesiology, University of Nebraska
Medical Center (UNMC), Omaha, Nebraska 68198, United States
- Department
of Genetics, Cell Biology, and Anatomy, UNMC, Omaha, Nebraska 68198, United States
- National
Strategic Research Institute, UNMC, Omaha, Nebraska 68198, United States
| | - Jian Yang
- Drug
Discovery and Development Research Group, College of Pharmacy and
Nutrition, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Saravana Babu Chidambaram
- Department
of Pharmacology, JSS College of Pharmacy, JSS Academy of Higher Education and Research, Mysuru 570015, India
- Centre
for Experimental Pharmacology and Toxicology, Central Animal Facility, JSS Academy of Higher Education and Research, Mysuru 570015, India
| | - Meena Kishore Sakharkar
- Drug
Discovery and Development Research Group, College of Pharmacy and
Nutrition, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Arehally M. Mahalakshmi
- Department
of Pharmacology, JSS College of Pharmacy, JSS Academy of Higher Education and Research, Mysuru 570015, India
- Centre
for Experimental Pharmacology and Toxicology, Central Animal Facility, JSS Academy of Higher Education and Research, Mysuru 570015, India
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3
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Zhu Y, Jian X, Chen S, An G, Jiang D, Yang Q, Zhang J, Hu J, Qiu Y, Feng X, Guo J, Chen X, Li Z, Zhou R, Hu C, He N, Shi F, Huang S, Liu H, Li X, Xie L, Zhu Y, Zhao L, Jiang Y, Li J, Wang J, Qiu L, Chen X, Jia W, He Y, Zhou W. Targeting gut microbial nitrogen recycling and cellular uptake of ammonium to improve bortezomib resistance in multiple myeloma. Cell Metab 2024; 36:159-175.e8. [PMID: 38113887 DOI: 10.1016/j.cmet.2023.11.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 10/17/2023] [Accepted: 11/30/2023] [Indexed: 12/21/2023]
Abstract
The gut microbiome has been found to play a crucial role in the treatment of multiple myeloma (MM), which is still considered incurable due to drug resistance. In previous studies, we demonstrated that intestinal nitrogen-recycling bacteria are enriched in patients with MM. However, their role in MM relapse remains unclear. This study highlights the specific enrichment of Citrobacter freundii (C. freundii) in patients with relapsed MM. Through fecal microbial transplantation experiments, we demonstrate that C. freundii plays a critical role in inducing drug resistance in MM by increasing levels of circulating ammonium. The ammonium enters MM cells through the transmembrane channel protein SLC12A2, promoting chromosomal instability and drug resistance by stabilizing the NEK2 protein. We show that furosemide sodium, a loop diuretic, downregulates SLC12A2, thereby inhibiting ammonium uptake by MM cells and improving progression-free survival and curative effect scores. These findings provide new therapeutic targets and strategies for the intervention of MM progression and drug resistance.
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Affiliation(s)
- Yinghong Zhu
- Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Experimental Hematology, Bioinformatics Center, National Clinical Research Center for Geriatric Disorders, Key Laboratory for Carcinogenesis and Invasion, Chinese Ministry of Education, Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Furong Laboratory, Department of Hematology, Xiangya Hospital, Central South University, Changsha, Hunan, China; Cancer Research Institute, School of Basic Medical Sciences, Central South University, Changsha, Hunan, China
| | - Xingxing Jian
- Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Experimental Hematology, Bioinformatics Center, National Clinical Research Center for Geriatric Disorders, Key Laboratory for Carcinogenesis and Invasion, Chinese Ministry of Education, Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Furong Laboratory, Department of Hematology, Xiangya Hospital, Central South University, Changsha, Hunan, China; Department of Dermatology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Shuping Chen
- Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Experimental Hematology, Bioinformatics Center, National Clinical Research Center for Geriatric Disorders, Key Laboratory for Carcinogenesis and Invasion, Chinese Ministry of Education, Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Furong Laboratory, Department of Hematology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Gang An
- State Key Laboratory of Experimental Hematology, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Science & Peking Union Medical College, Tianjin, China
| | - Duanfeng Jiang
- Department of Hematology, Third Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Qin Yang
- Department of Hematology, Third Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Jingyu Zhang
- Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Experimental Hematology, Bioinformatics Center, National Clinical Research Center for Geriatric Disorders, Key Laboratory for Carcinogenesis and Invasion, Chinese Ministry of Education, Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Furong Laboratory, Department of Hematology, Xiangya Hospital, Central South University, Changsha, Hunan, China; Cancer Research Institute, School of Basic Medical Sciences, Central South University, Changsha, Hunan, China
| | - Jian Hu
- Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Experimental Hematology, Bioinformatics Center, National Clinical Research Center for Geriatric Disorders, Key Laboratory for Carcinogenesis and Invasion, Chinese Ministry of Education, Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Furong Laboratory, Department of Hematology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yi Qiu
- Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Experimental Hematology, Bioinformatics Center, National Clinical Research Center for Geriatric Disorders, Key Laboratory for Carcinogenesis and Invasion, Chinese Ministry of Education, Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Furong Laboratory, Department of Hematology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Xiangling Feng
- Xiangya School of Public Health, Central South University, Changsha, Hunan, China
| | - Jiaojiao Guo
- Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Experimental Hematology, Bioinformatics Center, National Clinical Research Center for Geriatric Disorders, Key Laboratory for Carcinogenesis and Invasion, Chinese Ministry of Education, Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Furong Laboratory, Department of Hematology, Xiangya Hospital, Central South University, Changsha, Hunan, China; Cancer Research Institute, School of Basic Medical Sciences, Central South University, Changsha, Hunan, China
| | - Xun Chen
- Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Experimental Hematology, Bioinformatics Center, National Clinical Research Center for Geriatric Disorders, Key Laboratory for Carcinogenesis and Invasion, Chinese Ministry of Education, Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Furong Laboratory, Department of Hematology, Xiangya Hospital, Central South University, Changsha, Hunan, China; Cancer Research Institute, School of Basic Medical Sciences, Central South University, Changsha, Hunan, China
| | - Zhengjiang Li
- Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Experimental Hematology, Bioinformatics Center, National Clinical Research Center for Geriatric Disorders, Key Laboratory for Carcinogenesis and Invasion, Chinese Ministry of Education, Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Furong Laboratory, Department of Hematology, Xiangya Hospital, Central South University, Changsha, Hunan, China; Cancer Research Institute, School of Basic Medical Sciences, Central South University, Changsha, Hunan, China
| | - Ruiqi Zhou
- Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Experimental Hematology, Bioinformatics Center, National Clinical Research Center for Geriatric Disorders, Key Laboratory for Carcinogenesis and Invasion, Chinese Ministry of Education, Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Furong Laboratory, Department of Hematology, Xiangya Hospital, Central South University, Changsha, Hunan, China; Cancer Research Institute, School of Basic Medical Sciences, Central South University, Changsha, Hunan, China
| | - Cong Hu
- Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Experimental Hematology, Bioinformatics Center, National Clinical Research Center for Geriatric Disorders, Key Laboratory for Carcinogenesis and Invasion, Chinese Ministry of Education, Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Furong Laboratory, Department of Hematology, Xiangya Hospital, Central South University, Changsha, Hunan, China; Cancer Research Institute, School of Basic Medical Sciences, Central South University, Changsha, Hunan, China
| | - Nihan He
- Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Experimental Hematology, Bioinformatics Center, National Clinical Research Center for Geriatric Disorders, Key Laboratory for Carcinogenesis and Invasion, Chinese Ministry of Education, Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Furong Laboratory, Department of Hematology, Xiangya Hospital, Central South University, Changsha, Hunan, China; Cancer Research Institute, School of Basic Medical Sciences, Central South University, Changsha, Hunan, China
| | - Fangming Shi
- Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Experimental Hematology, Bioinformatics Center, National Clinical Research Center for Geriatric Disorders, Key Laboratory for Carcinogenesis and Invasion, Chinese Ministry of Education, Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Furong Laboratory, Department of Hematology, Xiangya Hospital, Central South University, Changsha, Hunan, China; Cancer Research Institute, School of Basic Medical Sciences, Central South University, Changsha, Hunan, China
| | - Siqing Huang
- Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Experimental Hematology, Bioinformatics Center, National Clinical Research Center for Geriatric Disorders, Key Laboratory for Carcinogenesis and Invasion, Chinese Ministry of Education, Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Furong Laboratory, Department of Hematology, Xiangya Hospital, Central South University, Changsha, Hunan, China; Cancer Research Institute, School of Basic Medical Sciences, Central South University, Changsha, Hunan, China
| | - Hong Liu
- Department of Dermatology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Xin Li
- Department of Hematology, Third Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Lu Xie
- Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Experimental Hematology, Bioinformatics Center, National Clinical Research Center for Geriatric Disorders, Key Laboratory for Carcinogenesis and Invasion, Chinese Ministry of Education, Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Furong Laboratory, Department of Hematology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yan Zhu
- Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Experimental Hematology, Bioinformatics Center, National Clinical Research Center for Geriatric Disorders, Key Laboratory for Carcinogenesis and Invasion, Chinese Ministry of Education, Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Furong Laboratory, Department of Hematology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Lia Zhao
- Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Experimental Hematology, Bioinformatics Center, National Clinical Research Center for Geriatric Disorders, Key Laboratory for Carcinogenesis and Invasion, Chinese Ministry of Education, Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Furong Laboratory, Department of Hematology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yichuan Jiang
- Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Experimental Hematology, Bioinformatics Center, National Clinical Research Center for Geriatric Disorders, Key Laboratory for Carcinogenesis and Invasion, Chinese Ministry of Education, Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Furong Laboratory, Department of Hematology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Jian Li
- Peking Union Medical College Hospital, Chinese Academy Medical Society & Peking Union Medical College, Beijing, China
| | - Jinuo Wang
- Peking Union Medical College Hospital, Chinese Academy Medical Society & Peking Union Medical College, Beijing, China
| | - Lugui Qiu
- State Key Laboratory of Experimental Hematology, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Science & Peking Union Medical College, Tianjin, China
| | - Xiang Chen
- Department of Dermatology, Xiangya Hospital, Central South University, Changsha, Hunan, China.
| | - Wei Jia
- School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China.
| | - Yanjuan He
- Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Experimental Hematology, Bioinformatics Center, National Clinical Research Center for Geriatric Disorders, Key Laboratory for Carcinogenesis and Invasion, Chinese Ministry of Education, Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Furong Laboratory, Department of Hematology, Xiangya Hospital, Central South University, Changsha, Hunan, China.
| | - Wen Zhou
- Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Experimental Hematology, Bioinformatics Center, National Clinical Research Center for Geriatric Disorders, Key Laboratory for Carcinogenesis and Invasion, Chinese Ministry of Education, Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Furong Laboratory, Department of Hematology, Xiangya Hospital, Central South University, Changsha, Hunan, China; Cancer Research Institute, School of Basic Medical Sciences, Central South University, Changsha, Hunan, China; Xiangya School of Public Health, Central South University, Changsha, Hunan, China.
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4
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Wei Z, Xiong Q, Huang D, Wu Z, Chen Z. Causal relationship between blood metabolites and risk of five infections: a Mendelian randomization study. BMC Infect Dis 2023; 23:663. [PMID: 37805474 PMCID: PMC10559484 DOI: 10.1186/s12879-023-08662-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 10/02/2023] [Indexed: 10/09/2023] Open
Abstract
OBJECTIVE Infectious diseases continue to pose a significant threat in the field of global public health, and our understanding of their metabolic pathogenesis remains limited. However, the advent of genome-wide association studies (GWAS) offers an unprecedented opportunity to unravel the relationship between metabolites and infections. METHODS Univariable and multivariable Mendelian randomization (MR) was commandeered to elucidate the causal relationship between blood metabolism and five high-frequency infection phenotypes: sepsis, pneumonia, upper respiratory tract infections (URTI), urinary tract infections (UTI), and skin and subcutaneous tissue infection (SSTI). GWAS data for infections were derived from UK Biobank and the FinnGen consortium. The primary analysis was conducted using the inverse variance weighted method on the UK Biobank data, along with a series of sensitivity analyses. Subsequently, replication and meta-analysis were performed on the FinnGen consortium data. RESULTS After primary analysis and a series of sensitivity analyses, 17 metabolites were identified from UK Biobank that have a causal relationship with five infections. Upon joint analysis with the FinGen cohort, 7 of these metabolites demonstrated consistent associations. Subsequently, we conducted a multivariable Mendelian randomization analysis to confirm the independent effects of these metabolites. Among known metabolites, genetically predicted 1-stearoylglycerol (1-SG) (odds ratio [OR] = 0.561, 95% confidence interval [CI]: 0.403-0.780, P < 0.001) and 3-carboxy-4-methyl-5-propyl-2-furanpropanoate (CMPF) (OR = 0.780, 95%CI: 0.689-0.883, P < 0.001) was causatively associated with a lower risk of sepsis, and genetically predicted phenylacetate (PA) (OR = 1.426, 95%CI: 1.152-1.765, P = 0.001) and cysteine (OR = 1.522, 95%CI: 1.170-1.980, P = 0.002) were associated with an increased risk of UTI. Ursodeoxycholate (UDCA) (OR = 0.906, 95%CI: 0.829-0.990, P = 0.029) is a protective factor against pneumonia. Two unknown metabolites, X-12407 (OR = 1.294, 95%CI: 1.131-1.481, P < 0.001), and X-12847 (OR = 1.344, 95%CI: 1.152-1.568, P < 0.001), were also identified as independent risk factors for sepsis. CONCLUSIONS In this MR study, we demonstrated a causal relationship between blood metabolites and the risk of developing sepsis, pneumonia, and UTI. However, there was no evidence of a causal connection between blood metabolites and the risk of URTI or SSTI, indicating a need for larger-scale studies to further investigate susceptibility to certain infection phenotypes.
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Affiliation(s)
- Zhengxiao Wei
- Department of Clinical Laboratory, Chengdu Public Health Clinical Medical Center & Public Health Clinical Center of Chengdu University of Traditional Chinese Medicine, 377 Jingming Road, Jinjiang District, Chengdu, 610066, China.
| | - Qingqing Xiong
- Department of Scientific Research and Teaching, Chengdu Public Health Clinical Medical Center & Public Health Clinical Center of Chengdu University of Traditional Chinese Medicine, 377 Jingming Road, Jinjiang District, Chengdu, 610066, China
| | - Dan Huang
- Department of Clinical Laboratory, Chengdu Public Health Clinical Medical Center & Public Health Clinical Center of Chengdu University of Traditional Chinese Medicine, 377 Jingming Road, Jinjiang District, Chengdu, 610066, China
| | - Zhangjun Wu
- Department of Clinical Laboratory, Chengdu Public Health Clinical Medical Center & Public Health Clinical Center of Chengdu University of Traditional Chinese Medicine, 377 Jingming Road, Jinjiang District, Chengdu, 610066, China
| | - Zhu Chen
- Department of Scientific Research and Teaching, Chengdu Public Health Clinical Medical Center & Public Health Clinical Center of Chengdu University of Traditional Chinese Medicine, 377 Jingming Road, Jinjiang District, Chengdu, 610066, China
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5
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Thomsen KL, Eriksen PL, Kerbert AJC, De Chiara F, Jalan R, Vilstrup H. Role of ammonia in NAFLD: An unusual suspect. JHEP Rep 2023; 5:100780. [PMID: 37425212 PMCID: PMC10326708 DOI: 10.1016/j.jhepr.2023.100780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 03/29/2023] [Accepted: 03/30/2023] [Indexed: 07/11/2023] Open
Abstract
Mechanistically, the symptomatology and disease progression of non-alcoholic fatty liver disease (NAFLD) remain poorly understood, which makes therapeutic progress difficult. In this review, we focus on the potential importance of decreased urea cycle activity as a pathogenic mechanism. Urea synthesis is an exclusive hepatic function and is the body's only on-demand and definitive pathway to remove toxic ammonia. The compromised urea cycle activity in NAFLD is likely caused by epigenetic damage to urea cycle enzyme genes and increased hepatocyte senescence. When the urea cycle is dysfunctional, ammonia accumulates in liver tissue and blood, as has been demonstrated in both animal models and patients with NAFLD. The problem may be augmented by parallel changes in the glutamine/glutamate system. In the liver, the accumulation of ammonia leads to inflammation, stellate cell activation and fibrogenesis, which is partially reversible. This may be an important mechanism for the transition of bland steatosis to steatohepatitis and further to cirrhosis and hepatocellular carcinoma. Systemic hyperammonaemia has widespread negative effects on other organs. Best known are the cerebral consequences that manifest as cognitive disturbances, which are prevalent in patients with NAFLD. Furthermore, high ammonia levels induce a negative muscle protein balance leading to sarcopenia, compromised immune function and increased risk of liver cancer. There is currently no rational way to reverse reduced urea cycle activity but there are promising animal and human reports of ammonia-lowering strategies correcting several of the mentioned untoward aspects of NAFLD. In conclusion, the ability of ammonia-lowering strategies to control the symptoms and prevent the progression of NAFLD should be explored in clinical trials.
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Affiliation(s)
- Karen Louise Thomsen
- Department of Hepatology and Gastroenterology, Aarhus University Hospital, Denmark
- UCL Institute of Liver and Digestive Health, University College London, United Kingdom
| | - Peter Lykke Eriksen
- Department of Hepatology and Gastroenterology, Aarhus University Hospital, Denmark
| | - Annarein JC. Kerbert
- UCL Institute of Liver and Digestive Health, University College London, United Kingdom
| | - Francesco De Chiara
- UCL Institute of Liver and Digestive Health, University College London, United Kingdom
| | - Rajiv Jalan
- UCL Institute of Liver and Digestive Health, University College London, United Kingdom
- European Foundation for the Study of Chronic Liver Failure, Barcelona, Spain
| | - Hendrik Vilstrup
- Department of Hepatology and Gastroenterology, Aarhus University Hospital, Denmark
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6
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Shingina A, Mukhtar N, Wakim-Fleming J, Alqahtani S, Wong RJ, Limketkai BN, Larson AM, Grant L. Acute Liver Failure Guidelines. Am J Gastroenterol 2023; 118:1128-1153. [PMID: 37377263 DOI: 10.14309/ajg.0000000000002340] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 04/04/2023] [Indexed: 06/29/2023]
Abstract
Acute liver failure (ALF) is a rare, acute, potentially reversible condition resulting in severe liver impairment and rapid clinical deterioration in patients without preexisting liver disease. Due to the rarity of this condition, published studies are limited by the use of retrospective or prospective cohorts and lack of randomized controlled trials. Current guidelines represent the suggested approach to the identification, treatment, and management of ALF and represent the official practice recommendations of the American College of Gastroenterology. The scientific evidence was reviewed using the Grading of Recommendations, Assessment, Development and Evaluation process to develop recommendations. When no robust evidence was available, expert opinions were summarized using Key Concepts. Considering the variety of clinical presentations of ALF, individualization of care should be applied in specific clinical scenarios.
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Affiliation(s)
- Alexandra Shingina
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Nizar Mukhtar
- Department of Gastroenterology, Kaiser Permanente, San Francisco, California, USA
| | - Jamilé Wakim-Fleming
- Department of Gastroenterology, Hepatology & Nutrition, Digestive Disease and Surgery Institute, Cleveland Clinic Foundation, Cleveland Ohio, USA
| | - Saleh Alqahtani
- Division of Gastroenterology and Hepatology, Johns Hopkins University, Baltimore, Maryland, USA
- Liver Transplantation Unit, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
| | - Robert J Wong
- Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Palo Alto, California, Gastroenterology Section, Veterans Affairs Palo Alto Healthcare System, Palo Alto, California, USA
| | | | - Anne M Larson
- Division of Gastroenterology and Hepatology, University of Washington, Seattle, Washington, USA
| | - Lafaine Grant
- Division of Digestive and Liver Diseases, UT Southwestern Medical Center, Dallas, Texas, USA
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7
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Bell HN, Huber AK, Singhal R, Korimerla N, Rebernick RJ, Kumar R, El-Derany MO, Sajjakulnukit P, Das NK, Kerk SA, Solanki S, James JG, Kim D, Zhang L, Chen B, Mehra R, Frankel TL, Győrffy B, Fearon ER, Pasca di Magliano M, Gonzalez FJ, Banerjee R, Wahl DR, Lyssiotis CA, Green M, Shah YM. Microenvironmental ammonia enhances T cell exhaustion in colorectal cancer. Cell Metab 2023; 35:134-149.e6. [PMID: 36528023 PMCID: PMC9841369 DOI: 10.1016/j.cmet.2022.11.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 11/11/2022] [Accepted: 11/23/2022] [Indexed: 12/23/2022]
Abstract
Effective therapies are lacking for patients with advanced colorectal cancer (CRC). The CRC tumor microenvironment has elevated metabolic waste products due to altered metabolism and proximity to the microbiota. The role of metabolite waste in tumor development, progression, and treatment resistance is unclear. We generated an autochthonous metastatic mouse model of CRC and used unbiased multi-omic analyses to reveal a robust accumulation of tumoral ammonia. The high ammonia levels induce T cell metabolic reprogramming, increase exhaustion, and decrease proliferation. CRC patients have increased serum ammonia, and the ammonia-related gene signature correlates with altered T cell response, adverse patient outcomes, and lack of response to immune checkpoint blockade. We demonstrate that enhancing ammonia clearance reactivates T cells, decreases tumor growth, and extends survival. Moreover, decreasing tumor-associated ammonia enhances anti-PD-L1 efficacy. These findings indicate that enhancing ammonia detoxification can reactivate T cells, highlighting a new approach to enhance the efficacy of immunotherapies.
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Affiliation(s)
- Hannah N Bell
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Amanda K Huber
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA
| | - Rashi Singhal
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Navyateja Korimerla
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA; University of Michigan Rogel Cancer Center, University of Michigan, Ann Arbor, MI, USA
| | - Ryan J Rebernick
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Roshan Kumar
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Marwa O El-Derany
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA; Department of Biochemistry, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt
| | - Peter Sajjakulnukit
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Nupur K Das
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Samuel A Kerk
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sumeet Solanki
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jadyn G James
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA
| | - Donghwan Kim
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Li Zhang
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Brandon Chen
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Rohit Mehra
- Department of Pathology, University of Michigan, Ann Arbor, MI, USA
| | - Timothy L Frankel
- Department of Surgery, University of Michigan, Ann Arbor, MI, USA; Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Balázs Győrffy
- Department of Bioinformatics and 2(nd) Department of Pediatrics, Semmelweis University, Budapest, Hungary; TTK Cancer Biomarker Research Group, Institute of Enzymology, Budapest, Hungary
| | - Eric R Fearon
- University of Michigan Rogel Cancer Center, University of Michigan, Ann Arbor, MI, USA; Department of Pathology, University of Michigan, Ann Arbor, MI, USA; Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA; Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Marina Pasca di Magliano
- Department of Surgery, University of Michigan, Ann Arbor, MI, USA; Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Frank J Gonzalez
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Ruma Banerjee
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Daniel R Wahl
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA; University of Michigan Rogel Cancer Center, University of Michigan, Ann Arbor, MI, USA
| | - Costas A Lyssiotis
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA; University of Michigan Rogel Cancer Center, University of Michigan, Ann Arbor, MI, USA; Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Michael Green
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA; University of Michigan Rogel Cancer Center, University of Michigan, Ann Arbor, MI, USA; Veteran's Affairs Ann Arbor Healthcare System, Ann Arbor, MI, USA
| | - Yatrik M Shah
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA; University of Michigan Rogel Cancer Center, University of Michigan, Ann Arbor, MI, USA; Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA.
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Hadjihambi A, Cudalbu C, Pierzchala K, Simicic D, Donnelly C, Konstantinou C, Davies N, Habtesion A, Gourine AV, Jalan R, Hosford PS. Abnormal brain oxygen homeostasis in an animal model of liver disease. JHEP Rep 2022; 4:100509. [PMID: 35865351 PMCID: PMC9293761 DOI: 10.1016/j.jhepr.2022.100509] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 04/23/2022] [Accepted: 05/10/2022] [Indexed: 01/15/2023] Open
Abstract
Background & Aims Increased plasma ammonia concentration and consequent disruption of brain energy metabolism could underpin the pathogenesis of hepatic encephalopathy (HE). Brain energy homeostasis relies on effective maintenance of brain oxygenation, and dysregulation impairs neuronal function leading to cognitive impairment. We hypothesised that HE is associated with reduced brain oxygenation and we explored the potential role of ammonia as an underlying pathophysiological factor. Methods In a rat model of chronic liver disease with minimal HE (mHE; bile duct ligation [BDL]), brain tissue oxygen measurement, and proton magnetic resonance spectroscopy were used to investigate how hyperammonaemia impacts oxygenation and metabolic substrate availability in the central nervous system. Ornithine phenylacetate (OP, OCR-002; Ocera Therapeutics, CA, USA) was used as an experimental treatment to reduce plasma ammonia concentration. Results In BDL animals, glucose, lactate, and tissue oxygen concentration in the cerebral cortex were significantly lower than those in sham-operated controls. OP treatment corrected the hyperammonaemia and restored brain tissue oxygen. Although BDL animals were hypotensive, cortical tissue oxygen concentration was significantly improved by treatments that increased arterial blood pressure. Cerebrovascular reactivity to exogenously applied CO2 was found to be normal in BDL animals. Conclusions These data suggest that hyperammonaemia significantly decreases cortical oxygenation, potentially compromising brain energy metabolism. These findings have potential clinical implications for the treatment of patients with mHE. Lay summary Brain dysfunction is a serious complication of cirrhosis and affects approximately 30% of these patients; however, its treatment continues to be an unmet clinical need. This study shows that oxygen concentration in the brain of an animal model of cirrhosis is markedly reduced. Low arterial blood pressure and increased ammonia (a neurotoxin that accumulates in patients with liver failure) are shown to be the main underlying causes. Experimental correction of these abnormalities restored oxygen concentration in the brain, suggesting potential therapeutic avenues to explore.
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Key Words
- 1H-MRS, proton magnetic resonance spectroscopy
- AIT, Animal Imaging and Technology
- ALT, alanine transaminase
- ATZ, acetazolamide
- Ala, alanine
- Asc, ascorbate
- Asp, aspartate
- BDL, bile duct ligation
- BOLD, blood oxygen level dependent
- BP, blood pressure
- CBF, cerebral blood flow
- CIBM, Center for Biomedical Imaging
- CLD, chronic liver disease
- CMRO2, cerebral metabolic rate of oxygen
- CNS, central nervous system
- Chronic liver disease
- Cr, creatine
- EPFL, Ecole Polytechnique Fédérale de Lausanne
- GABA, γ-aminobutyric acid
- GPC, glycerophosphocholine
- GSH, glutathione
- Glc, glucose
- Gln, glutamine
- Glu, glutamate
- HE, hepatic encephalopathy
- Hyperammonaemia
- Ins, myo-inositol
- Lac, lactate
- MAP, mean arterial pressure
- NAA, N acetylaspartate
- NO, nitric oxide
- OP, ornithine phenylacetate
- Ornithine phenylacetate
- Oxygen
- PCho, phosphocholine
- PCr, phosphocreatine
- PE, phenylephrine
- Phenylephrine
- SPECIAL, spin echo full intensity acquired localised
- TE, echo time
- Tau, taurine
- VOI, volume of interest
- [18F]-FDG PET, [18F]-fluorodeoxyglucose positron emission tomography
- eNOS, endothelial nitric oxide synthase
- fMRI, functional magnetic resonance imaging
- hepatic encephalopathy
- mHE, minimal HE
- pCO2, partial pressure of carbon dioxide
- pO2, partial pressure of oxygen
- tCho, total choline
- tCr, total creatine
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Affiliation(s)
- Anna Hadjihambi
- UCL Institute for Liver and Digestive Health, Division of Medicine, UCL Medical School, Royal Free Hospital, Rowland Hill Street, London, UK
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, London, UK
- The Roger Williams Institute of Hepatology London, Foundation for Liver Research, London, UK
- Faculty of Life Sciences and Medicine, King’s College London, London, UK
| | - Cristina Cudalbu
- CIBM Center for Biomedical Imaging, Lausanne, Switzerland
- Animal Imaging and Technology, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Katarzyna Pierzchala
- CIBM Center for Biomedical Imaging, Lausanne, Switzerland
- Animal Imaging and Technology, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Laboratory of Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Dunja Simicic
- CIBM Center for Biomedical Imaging, Lausanne, Switzerland
- Animal Imaging and Technology, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Chris Donnelly
- Institute of Sports Science and Department of Physiology, University of Lausanne, Lausanne, Switzerland
| | - Christos Konstantinou
- The Roger Williams Institute of Hepatology London, Foundation for Liver Research, London, UK
- Faculty of Life Sciences and Medicine, King’s College London, London, UK
| | - Nathan Davies
- UCL Institute for Liver and Digestive Health, Division of Medicine, UCL Medical School, Royal Free Hospital, Rowland Hill Street, London, UK
| | - Abeba Habtesion
- UCL Institute for Liver and Digestive Health, Division of Medicine, UCL Medical School, Royal Free Hospital, Rowland Hill Street, London, UK
| | - Alexander V. Gourine
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Rajiv Jalan
- UCL Institute for Liver and Digestive Health, Division of Medicine, UCL Medical School, Royal Free Hospital, Rowland Hill Street, London, UK
- European Foundation for the Study of Chronic Liver Failure
| | - Patrick S. Hosford
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, London, UK
- William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, London, UK
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El Okle OS, Tohamy HG, Althobaiti SA, Soliman MM, Ghamry HI, Farrag F, Shukry M. Ornipural® Mitigates Malathion-Induced Hepato-Renal Damage in Rats via Amelioration of Oxidative Stress Biomarkers, Restoration of Antioxidant Activity, and Attenuation of Inflammatory Response. Antioxidants (Basel) 2022; 11:antiox11040757. [PMID: 35453442 PMCID: PMC9031224 DOI: 10.3390/antiox11040757] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 04/07/2022] [Accepted: 04/08/2022] [Indexed: 02/01/2023] Open
Abstract
The current study was instigated by investigating the ameliorative potential of Ornipural® solution against the hepato-renal toxicity of malathion. A total number of 35 male Wistar albino rats were divided equally into five groups. Group 1 served as control and received normal saline intraperitoneally. Group 2, the sham group, were administered only corn oil (vehicle of malathion) orally. Group 3 was orally intoxicated by malathion in corn oil at a dose of 135 mg/kg BW via intra-gastric gavage. Group 4 received malathion orally concomitantly with Ornipural® intraperitoneally. Group 5 was given Ornipural® solution in saline via intraperitoneal injection at a dose of (1 mL/kg BW). Animals received the treatment regime for 30 days. Histopathological examination revealed the harmful effect of malathion on hepatic and renal tissue. The results showed that malathion induced a significant decrease in body weight and marked elevation in the activity of liver enzymes, LDH, and ACP. In contrast, the activity of AchE and Paraoxonase was markedly decreased. Moreover, there was a significant increase in the serum content of bilirubin, cholesterol, and kidney injury markers. A significant elevation in malondialdehyde, nitric oxide (nitrite), and 8-hydroxy-2-deoxyguanosine was observed, along with a substantial reduction in antioxidant activity. Furthermore, malathion increased tumor necrosis factor-alpha, the upregulation of IL-1B, BAX, and IFN-β genes, and the downregulation of Nrf2, Bcl2, and HO-1 genes. Concurrent administration of Ornipural® with malathion attenuated the detrimental impact of malathion through ameliorating metabolic biomarkers, restoring antioxidant activity, reducing the inflammatory response, and improving pathologic microscopic alterations. It could be concluded that Ornipural® solution demonstrates hepatorenal defensive impacts against malathion toxicity at biochemical, antioxidants, molecular, and cellular levels.
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Affiliation(s)
- Osama S. El Okle
- Departement of Forensic Medicine and Toxicology, Faculty of Veterinary Medicine, Alexandria University, Alexandria 22758, Egypt;
| | - Hossam G. Tohamy
- Departement of Pathology, Faculty of Veterinary Medicine, Alexandria University, Alexandria 22758, Egypt;
| | - Saed A. Althobaiti
- Biology Department, Turabah University College, Taif University, Taif 21995, Saudi Arabia;
| | - Mohamed Mohamed Soliman
- Clinical Laboratory Sciences Department, Turabah University College, Taif University, Taif 21995, Saudi Arabia;
| | - Heba I. Ghamry
- Department of Home Economics, College of Home Economics, King Khalid University, P.O. Box 960, Abha 61421, Saudi Arabia;
| | - Foad Farrag
- Department of Anatomy and Embryology, Faculty of Veterinary Medicine, Kafrelsheikh University, Kafrelsheikh 33516, Egypt;
| | - Mustafa Shukry
- Department of Physiology, Faculty of Veterinary Medicine, Kafrelsheikh University, Kafrelsheikh 33516, Egypt
- Correspondence:
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DeMorrow S, Cudalbu C, Davies N, Jayakumar AR, Rose CF. 2021 ISHEN guidelines on animal models of hepatic encephalopathy. Liver Int 2021; 41:1474-1488. [PMID: 33900013 PMCID: PMC9812338 DOI: 10.1111/liv.14911] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 03/05/2021] [Accepted: 04/01/2021] [Indexed: 02/07/2023]
Abstract
This working group of the International Society of Hepatic Encephalopathy and Nitrogen Metabolism (ISHEN) was commissioned to summarize and update current efforts in the development and characterization of animal models of hepatic encephalopathy (HE). As defined in humans, HE in animal models is based on the underlying degree and severity of liver pathology. Although hyperammonemia remains the key focus in the pathogenesis of HE, other factors associated with HE have been identified, together with recommended animal models, to help explore the pathogenesis and pathophysiological mechanisms of HE. While numerous methods to induce liver failure and disease exist, less have been characterized with neurological and neurobehavioural impairments. Moreover, there still remains a paucity of adequate animal models of Type C HE induced by alcohol, viruses and non-alcoholic fatty liver disease; the most common etiologies of chronic liver disease.
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Affiliation(s)
- S DeMorrow
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Texas, USA; Department of Internal Medicine, Dell Medical School, The University of Texas at Austin, Texas, USA; Research division, Central Texas Veterans Healthcare System, Temple Texas USA.,Correspondance: Sharon DeMorrow, PhD, ; tel: +1-512-495-5779
| | - C Cudalbu
- Center for Biomedical Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - N Davies
- Institute for Liver and Digestive Health, University College London, Royal Free Campus, London, United Kingdom
| | - AR Jayakumar
- General Medical Research, Neuropathology Section, R&D Service and South Florida VA Foundation for Research and Education Inc; Obstetrics, Gynecology and Reproductive Sciences, University of Miami School of Medicine, Miami FL, USA
| | - CF Rose
- Hepato-Neuro Laboratory, CRCHUM, Université de Montréal, Montreal, Canada
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Clément MA, Bosoi CR, Oliveira MM, Tremblay M, Bémeur C, Rose CF. Bile-duct ligation renders the brain susceptible to hypotension-induced neuronal degeneration: Implications of ammonia. J Neurochem 2021; 157:561-573. [PMID: 33382098 DOI: 10.1111/jnc.15290] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 12/22/2020] [Accepted: 12/29/2020] [Indexed: 12/11/2022]
Abstract
Hepatic encephalopathy (HE) is a debilitating neurological complication of cirrhosis. By definition, HE is considered a reversible disorder, and therefore HE should resolve following liver transplantation (LT). However, persisting neurological complications are observed in as many as 47% of LT recipients. LT is an invasive surgical procedure accompanied by various perioperative factors such as blood loss and hypotension which could influence outcomes post-LT. We hypothesize that minimal HE (MHE) renders the brain frail and susceptible to hypotension-induced neuronal cell death. Six-week bile duct-ligated (BDL) rats with MHE and respective SHAM-controls were used. Several degrees of hypotension (mean arterial pressure of 30, 60 and 90 mm Hg) were induced via blood withdrawal from the femoral artery and maintained for 120 min. Brains were collected for neuronal cell count and apoptotic analysis. In a separate group, BDL rats were treated for MHE with the ammonia-lowering strategy ornithine phenylacetate (OP; MNK-6105), administered orally (1 g/kg) for 3 weeks before induction of hypotension. Hypotension 30 and 60 mm Hg (not 90 mm Hg) significantly decreased neuronal marker expression (NeuN) and cresyl violet staining in the frontal cortex compared to respective hypotensive SHAM-operated controls as well as non-hypotensive BDL rats. Neuronal degeneration was associated with an increase in cleaved caspase-3, suggesting the mechanism of cell death was apoptotic. OP treatment attenuated hyperammonaemia, improved anxiety and activity, and protected the brain against hypotension-induced neuronal cell death. Our findings demonstrate that rats with chronic liver disease and MHE are more susceptible to hypotension-induced neuronal cell degeneration. This highlights MHE at the time of LT is a risk factor for poor neurological outcome post-transplant and that treating for MHE pre-LT might reduce this risk.
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Affiliation(s)
- Marc-André Clément
- Hepato-Neuro Laboratory, CRCHUM, Université de Montréal, Montréal, Canada
| | - Cristina R Bosoi
- Hepato-Neuro Laboratory, CRCHUM, Université de Montréal, Montréal, Canada
| | - Mariana M Oliveira
- Hepato-Neuro Laboratory, CRCHUM, Université de Montréal, Montréal, Canada
| | - Mélanie Tremblay
- Hepato-Neuro Laboratory, CRCHUM, Université de Montréal, Montréal, Canada
| | - Chantal Bémeur
- Hepato-Neuro Laboratory, CRCHUM, Université de Montréal, Montréal, Canada
| | - Christopher F Rose
- Hepato-Neuro Laboratory, CRCHUM, Université de Montréal, Montréal, Canada
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Braissant O, Rackayová V, Pierzchala K, Grosse J, McLin VA, Cudalbu C. Longitudinal neurometabolic changes in the hippocampus of a rat model of chronic hepatic encephalopathy. J Hepatol 2019; 71:505-515. [PMID: 31173812 DOI: 10.1016/j.jhep.2019.05.022] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 05/24/2019] [Accepted: 05/27/2019] [Indexed: 12/20/2022]
Abstract
BACKGROUND & AIMS The sequence of events in hepatic encephalopathy (HE) remains unclear. Using the advantages of in vivo 1H-MRS (9.4T) we aimed to analyse the time-course of disease in an established model of type C HE by analysing the longitudinal changes in a large number of brain metabolites together with biochemical, histological and behavioural assessment. We hypothesized that neurometabolic changes are detectable very early, and that these early changes will offer insight into the primary events underpinning HE. METHODS Wistar rats underwent bile-duct ligation (BDL) and were studied before BDL and at post-operative weeks 2, 4, 6 and 8 (n = 26). In vivo short echo-time 1H-MRS (9.4T) of the hippocampus was performed in a longitudinal manner, as were biochemical (plasma), histological and behavioural tests. RESULTS Plasma ammonium increased early after BDL and remained high during the study. Brain glutamine increased (+47%) as early as 2-4 weeks post-BDL while creatine (-8%) and ascorbate (-12%) decreased. Brain glutamine and ascorbate correlated closely with rising plasma ammonium, while brain creatine correlated with brain glutamine. The increases in brain glutamine and plasma ammonium were correlated, while plasma ammonium correlated negatively with distance moved. Changes in astrocyte morphology were observed at 4 weeks. These early changes were further accentuated at 6-8 weeks post-BDL, concurrently with the known decreases in brain organic osmolytes. CONCLUSION Using a multimodal, in vivo and longitudinal approach we have shown that neurometabolic changes are already noticeable 2 weeks after BDL. These early changes are suggestive of osmotic/oxidative stress and are likely the premise of some later changes. Early decreases in cerebral creatine and ascorbate are novel findings offering new avenues to explore neuroprotective strategies for HE treatment. LAY SUMMARY The sequence of events in chronic hepatic encephalopathy (HE) remains unclear, therefore using the advantages of in vivo proton magnetic resonance spectroscopy at 9.4T we aimed to test the hypothesis that neurometabolic changes are detectable very early in an established model of type C HE, offering insight into the primary events underpinning HE, before advanced liver disease confounds the findings. These early, previously unreported neurometabolic changes occurred as early as 2 to 4 weeks after bile-duct ligation, namely an increase in plasma ammonium and brain glutamine, a decrease in brain creatine and ascorbate together with behavioural and astrocyte morphology changes, and continued to progress throughout the 8-week course of the disease.
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Affiliation(s)
- Olivier Braissant
- Service of Clinical Chemistry, University of Lausanne and University Hospital of Lausanne, Lausanne, Switzerland
| | - Veronika Rackayová
- Laboratory of Functional and Metabolic Imaging, Center for Biomedical Imaging, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland; Centre d'Imagerie Biomedicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Katarzyna Pierzchala
- Centre d'Imagerie Biomedicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Jocelyn Grosse
- Laboratory of Behavioral Genetics, Brain Mind Institute, School Of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Valérie A McLin
- Swiss Pediatric Liver Center, Department of Pediatrics, Gynecology and Obstetrics, University Hospitals Geneva, and University of Geneva Medical School, Switzerland
| | - Cristina Cudalbu
- Centre d'Imagerie Biomedicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
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Contreras-Zentella ML, Sánchez-Sevilla L, Suárez-Cuenca JA, Olguín-Martínez M, Alatriste-Contreras MG, García-García N, Orozco L, Hernández-Muñoz R. The role of oxidant stress and gender in the erythrocyte arginine metabolism and ammonia management in patients with type 2 diabetes. PLoS One 2019; 14:e0219481. [PMID: 31314811 PMCID: PMC6636741 DOI: 10.1371/journal.pone.0219481] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Accepted: 06/25/2019] [Indexed: 12/30/2022] Open
Abstract
OBJECTIVES To study the differences in the levels of nitrogen metabolites, such as ammonia and nitric oxide and the correlations existing among them in both red blood cells (RBCs) and serum, as well as the possible differences by gender in healthy subjects and patients with type 2 Diabetes Mellitus (DM). DESIGN AND METHODS This cross-sectional study included 80 patients diagnosed with type 2 DM (40 female and 40 male patients) and their corresponding controls paired by gender (40 female and 40 male). We separated serum and RBC and determined metabolites mainly through colorimetric and spectrophotometric assays. We evaluated changes in the levels of the main catabolic by-products of blood nitrogen metabolism, nitric oxide (NO), and malondialdehyde (MDA). RESULTS Healthy female and male controls showed a differential distribution of blood metabolites involved in NO metabolism and arginine metabolism for the ornithine and urea formation. Patients with DM had increased ammonia, citrulline, urea, uric acid, and ornithine, mainly in the RBCs, whereas the level of arginine was significantly lower in men with type 2 DM. These findings were associated with hyperglycemia, glycosylated hemoglobin (Hb A1C), and levels of RBC's MDA. Furthermore, most of the DM-induced alterations in nitrogen-related metabolites appear to be associated with a difference in the RBC capacity for the release of these metabolites, thereby causing an abrogation of the gender-related differential management of nitrogen metabolites in healthy subjects. CONCLUSIONS We found evidence of a putative role of RBC as an extra-hepatic mechanism for controlling serum levels of nitrogen-related metabolites, which differs according to gender in healthy subjects. Type 2 DM promotes higher ammonia, citrulline, and MDA blood levels, which culminate in a loss of the differential management of nitrogen-related metabolites seen in healthy women and men.
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Affiliation(s)
- Martha L. Contreras-Zentella
- Departamento de Biología Celular y Desarrollo, Instituto de Fisiología Celular; Universidad Nacional Autónoma de México (UNAM), Coyoacán, Mexico City, Mexico
| | - Lourdes Sánchez-Sevilla
- Departamento de Biología Celular y Desarrollo, Instituto de Fisiología Celular; Universidad Nacional Autónoma de México (UNAM), Coyoacán, Mexico City, Mexico
| | - Juan A. Suárez-Cuenca
- Departamento de Medicina Interna, Hospital General “Xoco”, Secretaría de Salubridad, Coyoacàn, Mexico City, Mexico
| | - Marisela Olguín-Martínez
- Departamento de Biología Celular y Desarrollo, Instituto de Fisiología Celular; Universidad Nacional Autónoma de México (UNAM), Coyoacán, Mexico City, Mexico
| | - Martha G. Alatriste-Contreras
- Departamento de Métodos Cuantitativos, División de Estudios Profesionales, Facultad de Economía, Universidad Nacional Autónoma de México (UNAM), Coyoacán, Mexico City, Mexico
| | - Norberto García-García
- Departamento de Biología Celular y Desarrollo, Instituto de Fisiología Celular; Universidad Nacional Autónoma de México (UNAM), Coyoacán, Mexico City, Mexico
| | - Lorena Orozco
- Laboratorio de Enfermedades Inmunogénicas y Metabólicas, Instituto Nacional de Medicina Genómica (INMEGEN), Tlalpan, Mexico City, Mexico
| | - Rolando Hernández-Muñoz
- Departamento de Biología Celular y Desarrollo, Instituto de Fisiología Celular; Universidad Nacional Autónoma de México (UNAM), Coyoacán, Mexico City, Mexico
- * E-mail:
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Cudalbu C, Taylor-Robinson SD. Brain Edema in Chronic Hepatic Encephalopathy. J Clin Exp Hepatol 2019; 9:362-382. [PMID: 31360029 PMCID: PMC6637228 DOI: 10.1016/j.jceh.2019.02.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 01/15/2019] [Accepted: 02/06/2019] [Indexed: 02/07/2023] Open
Abstract
Brain edema is a common feature associated with hepatic encephalopathy (HE). In patients with acute HE, brain edema has been shown to play a crucial role in the associated neurological deterioration. In chronic HE, advanced magnetic resonance imaging (MRI) techniques have demonstrated that low-grade brain edema appears also to be an important pathological feature. This review explores the different methods used to measure brain edema ex vivo and in vivo in animal models and in humans with chronic HE. In addition, an in-depth description of the main studies performed to date is provided. The role of brain edema in the neurological alterations linked to HE and whether HE and brain edema are the manifestations of the same pathophysiological mechanism or two different cerebral manifestations of brain dysfunction in liver disease are still under debate. In vivo MRI/magnetic resonance spectroscopy studies have allowed insight into the development of brain edema in chronic HE. However, additional in vivo longitudinal and multiparametric/multimodal studies are required (in humans and animal models) to elucidate the relationship between liver function, brain metabolic changes, cellular changes, cell swelling, and neurological manifestations in chronic HE.
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Key Words
- 1H MRS, proton magnetic resonance spectroscopy
- ADC, apparent diffusion coefficient
- ALF, acute liver failure
- AQP, aquaporins
- BBB, blood-brain barrier
- BDL, bile duct ligation
- CNS, central nervous system
- CSF, cerebrospinal fluid
- Cr, creatine
- DTI, diffusion tensor imaging
- DWI, diffusion-weighted imaging
- FLAIR, fluid-attenuated inversion recovery
- GM, gray matter
- Gln, glutamine
- Glx, sum of glutamine and glutamate
- HE, hepatic encephalopathy
- Ins, inositol
- LPS, lipopolysaccharide
- Lac, lactate
- MD, mean diffusivity
- MRI, magnetic resonance imaging
- MRS, magnetic resonance spectroscopy
- MT, magnetization transfer
- MTR, MT ratio
- NMR, nuclear magnetic resonance
- PCA, portocaval anastomosis
- TE, echo time
- WM, white matter
- brain edema
- chronic hepatic encephalopathy
- in vivo magnetic resonance imaging
- in vivo magnetic resonance spectroscopy
- liver cirrhosis
- mIns, myo-inositol
- tCho, total choline
- tCr, total creatine
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Affiliation(s)
- Cristina Cudalbu
- Centre d'Imagerie Biomedicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland,Address for correspondence: Cristina Cudalbu, Centre d'Imagerie Biomedicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), EPFL-CIBM, Office F3 628, Station 6, CH-1015 Lausanne, Switzerland.
| | - Simon D. Taylor-Robinson
- Division of Integrative Systems Medicine and Digestive Disease, Department of Surgery and Cancer, St Mary's Hospital Campus, Imperial College London, London, United Kingdom
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Kim JY, Ri HS, Yoon JU, Choi EJ, Kim HJ, Park JY. Fatal neurological complication after liver transplantation in acute hepatic failure patient with hepatic encephalopathy. KOSIN MEDICAL JOURNAL 2018. [DOI: 10.7180/kmj.2018.33.1.96] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Liver transplantation is a current definitive treatment for those with end-stage liver disease. Hepatic encephalopathy is a common complication of hepatic failure, which can be improved and aggravated by various causes. It is important to differentiate hepatic encephalopathy from other diseases causing brain dysfunction such as cerebral hemorrhage, which is also related to high mortality after liver transplant surgery. A 37-year-old patient was presented with acute liver failure and high ammonia levels and seizure-like symptoms. Computed tomography (CT) of his brain showed mild brain atrophy, regarded as a symptom of hepatic encephalopathy, and treated to decrease blood ammonia level. Deceased donor liver transplantation was performed and liver function and ammonia level normalized after surgery, but the patient showed symptoms of involuntary muscle contraction and showed loss of pupil reflex and fixation without recovery of consciousness. Brain CT showed brain edema and bilateral cerebral infarction, and the patient died after a few days. The purpose of this case report is to emphasize the importance of preoperative neurological evaluation, careful transplantation decision, and proper perioperative management of liver transplantation in patients with acute hepatic encephalopathy.
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16
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Stravitz RT, Gottfried M, Durkalski V, Fontana RJ, Hanje AJ, Koch D, Hameed B, Ganger D, Subramanian RM, Bukofzer S, Ravis WR, Clasen K, Sherker A, Little L, Lee WM. Safety, tolerability, and pharmacokinetics of l-ornithine phenylacetate in patients with acute liver injury/failure and hyperammonemia. Hepatology 2018; 67:1003-1013. [PMID: 29080224 PMCID: PMC5826861 DOI: 10.1002/hep.29621] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2017] [Revised: 08/03/2017] [Accepted: 10/25/2017] [Indexed: 12/12/2022]
Abstract
Cerebral edema remains a significant cause of morbidity and mortality in patients with acute liver failure (ALF) and has been linked to elevated blood ammonia levels. l-ornithine phenylacetate (OPA) may decrease ammonia by promoting its renal excretion as phenylacetylglutamine (PAGN), decreasing the risk of cerebral edema. We evaluated the safety, tolerability, and pharmacokinetics of OPA in patients with ALF and acute liver injury (ALI), including those with renal failure. Forty-seven patients with ALI/ALF and ammonia ≥60 μM were enrolled. Patients received OPA in a dose escalation scheme from 3.3 g every 24 hours to 10 g every 24 hours; 15 patients received 20 g every 24 hours throughout the infusion for up to 120 hours. Plasma phenylacetate (PA) concentrations were uniformly below target (<75 μg/mL) in those receiving 3.3 g every 24 hours (median [interquartile range] 5.0 [5.0] μg/mL), and increased to target levels in all but one who received 20 g every 24 hours (150 [100] μg/mL). Plasma [PAGN] increased, and conversion of PA to PAGN became saturated, with increasing OPA dose. Urinary PAGN clearance and creatinine clearance were linearly related (r = 0.831, P < 0.0001). Mean ammonia concentrations based on the area under the curve decreased to a greater extent in patients who received 20 g of OPA every 24 hours compared with those who received the maximal dose of 3.3 or 6.7 g every 24 hours (P = 0.046 and 0.022, respectively). Of the reported serious adverse events (AEs), which included 11 deaths, none was attributable to study medication. The only nonserious AEs possibly related to study drug were headache and nausea/vomiting. CONCLUSION OPA was well-tolerated in patients with ALI/ALF, and no safety signals were identified. Target [PA] was achieved at infusion rates of 20 g every 24 hours, leading to ammonia excretion in urine as PAGN in proportion to renal function. Randomized, controlled studies of high-dose OPA are needed to determine its use as an ammonia-scavenging agent in patients with ALF. (Hepatology 2018;67:1003-1013).
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Affiliation(s)
| | | | | | | | | | - David Koch
- Medical University of South Carolina, Charleston, SC
| | - Bilal Hameed
- University of California at San Francisco, San Francisco, CA
| | | | | | | | | | | | - Averell Sherker
- National Institute of Diabetes, Digestive and Kidney Disease, Bethesda, MD
| | - Lanna Little
- University of Texas, Southwestern Medical Center, Dallas, TX
| | - William M. Lee
- University of Texas, Southwestern Medical Center, Dallas, TX
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Mancini A, Campagna F, Amodio P, Tuohy KM. Gut : liver : brain axis: the microbial challenge in the hepatic encephalopathy. Food Funct 2018; 9:1373-1388. [PMID: 29485654 DOI: 10.1039/c7fo01528c] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Hepatic encephalopathy (HE) is a debilitating neuropsychiatric condition often associated with acute liver failure or cirrhosis. Advanced liver diseases are characterized by a leaky gut and systemic inflammation. There is strong evidence that the pathogenesis of HE is linked to a dysbiotic gut microbiota and to harmful microbial by-products, such as ammonia, indoles, oxindoles and endotoxins. Increased concentrations of these toxic metabolites together with the inability of the diseased liver to clear such products is thought to play an important patho-ethiological role. Current first line clinical treatments target microbiota dysbiosis by decreasing the counts of pathogenic bacteria, blood endotoxemia and ammonia levels. This review will focus on the role of the gut microbiota and its metabolism in HE and advanced cirrhosis. It will critically assess data from different clinical trials measuring the efficacy of the prebiotic lactulose, the probiotic VSL#3 and the antibiotic rifaximin in treating HE and advanced cirrhosis, through gut microbiota modulation. Additionally data from Randomised Controlled Trials using pre-, pro- and synbiotic will be also considered by reporting meta-analysis studies. The large amount of existing data showed that HE is a clear example of how an altered gut microbiota homeostasis can influence and impact on physiological functions outside the intestine, with implication for host health at the systems level. Nevertheless, a strong effort should be made to increase the information on gut microbiota ecology and its metabolic function in liver diseases and HE.
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Affiliation(s)
- Andrea Mancini
- Department of Food Quality and Nutrition, Research and Innovation Centre, Fondazione Edmund Mach, 38010 San Michele all'Adige, Trento, Italy.
| | - Francesca Campagna
- Department of Medicine (DIMED), University of Padova, 35128 Padova, Italy
| | - Piero Amodio
- Department of Medicine (DIMED), University of Padova, 35128 Padova, Italy
| | - Kieran M Tuohy
- Department of Food Quality and Nutrition, Research and Innovation Centre, Fondazione Edmund Mach, 38010 San Michele all'Adige, Trento, Italy.
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18
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The Pharmabiotic Approach to Treat Hyperammonemia. Nutrients 2018; 10:nu10020140. [PMID: 29382084 PMCID: PMC5852716 DOI: 10.3390/nu10020140] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 01/22/2018] [Accepted: 01/26/2018] [Indexed: 12/12/2022] Open
Abstract
Ammonia is constantly produced as a metabolic waste from amino acid catabolism in mammals. Ammonia, the toxic waste metabolite, is resolved in the liver where the urea cycle converts free ammonia to urea. Liver malfunctions cause hyperammonemia that leads to central nervous system (CNS) dysfunctions, such as brain edema, convulsions, and coma. The current treatments for hyperammonemia, such as antibiotics or lactulose, are designed to decrease the intestinal production of ammonia and/or its absorption into the body and are not effective, besides being often accompanied by side effects. In recent years, increasing evidence has shown that modifications of the gut microbiota could be used to treat hyperammonemia. Considering the role of the gut microbiota and the physiological characteristics of the intestine, the removal of ammonia from the intestine by modulating the gut microbiota would be an ideal approach to treat hyperammonemia. In this review, we discuss the significance of hyperammonemia and its related diseases and the efficacy of the current management methods for hyperammonemia to understand the mechanism of ammonia transport in the human body. The possibility to use the gut microbiota as pharmabiotics to treat hyperammonemia and its related diseases is also explored.
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19
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Weiss N, Tripon S, Lodey M, Guiller E, Junot H, Monneret D, Mayaux J, Brisson H, Mallet M, Rudler M, Imbert-Bismut F, Thabut D. Treating hepatic encephalopathy in cirrhotic patients admitted to ICU with sodium phenylbutyrate: a preliminary study. Fundam Clin Pharmacol 2018; 32:209-215. [DOI: 10.1111/fcp.12340] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Revised: 10/21/2017] [Accepted: 12/01/2017] [Indexed: 01/04/2023]
Affiliation(s)
- Nicolas Weiss
- Brain-Liver Pitié-Salpêtrière Study Group (BLIPS); Hôpital de la Pitié-Salpêtrière; Assistance Publique-Hôpitaux de Paris; INSERM UMR_S 938, CDR Saint-Antoine & Institut de Cardiométabolisme et Nutrition (ICAN); 47-83 boulevard de l'Hôpital 75013 Paris France
- UPMC Univ Paris 06 & Unité de réanimation neurologique; Département de Neurologie; Pôle des maladies du système nerveux; Hôpital de la Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris; Sorbonne Universités; 47-83 boulevard de l'Hôpital 75013 Paris France
- Institut de Neurosciences Translationnelles de Paris; Institut-Hospitalo-Universitaire-A-Institut du Cerveau et de la Moelle (IHU-A-ICM); 47-83 boulevard de l'Hôpital 75013 Paris France
| | - Simona Tripon
- Brain-Liver Pitié-Salpêtrière Study Group (BLIPS); Hôpital de la Pitié-Salpêtrière; Assistance Publique-Hôpitaux de Paris; INSERM UMR_S 938, CDR Saint-Antoine & Institut de Cardiométabolisme et Nutrition (ICAN); 47-83 boulevard de l'Hôpital 75013 Paris France
- UPMC Univ Paris 06 & Soins Intensifs d'Hépatologie; Service d'Hépato-Gastroentérologie; Hôpital de la Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris; 47-83 boulevard de l'Hôpital 75013 Paris France
| | - Marion Lodey
- Service de pharmacie; Hôpital de la Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris; 47-83 boulevard de l'Hôpital 75013 Paris France
| | - Elsa Guiller
- Service de pharmacie; Hôpital de la Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris; 47-83 boulevard de l'Hôpital 75013 Paris France
| | - Helga Junot
- Service de pharmacie; Hôpital de la Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris; 47-83 boulevard de l'Hôpital 75013 Paris France
| | - Denis Monneret
- Brain-Liver Pitié-Salpêtrière Study Group (BLIPS); Hôpital de la Pitié-Salpêtrière; Assistance Publique-Hôpitaux de Paris; INSERM UMR_S 938, CDR Saint-Antoine & Institut de Cardiométabolisme et Nutrition (ICAN); 47-83 boulevard de l'Hôpital 75013 Paris France
- Service de biochimie; Hôpital de la Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris; 47-83 boulevard de l'Hôpital 75013 Paris France
| | - Julien Mayaux
- Unité de Réanimation et de Surveillance continue; Service de Pneumologie et Réanimation médicale; Hôpital de la Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris; 47-83 boulevard de l'Hôpital 75013 Paris France
| | - Hélène Brisson
- Service de réanimation; Département d'anesthésie-réanimation; Hôpital de la Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris; 47-83 boulevard de l'Hôpital 75013 Paris France
| | - Maxime Mallet
- Brain-Liver Pitié-Salpêtrière Study Group (BLIPS); Hôpital de la Pitié-Salpêtrière; Assistance Publique-Hôpitaux de Paris; INSERM UMR_S 938, CDR Saint-Antoine & Institut de Cardiométabolisme et Nutrition (ICAN); 47-83 boulevard de l'Hôpital 75013 Paris France
- UPMC Univ Paris 06 & Soins Intensifs d'Hépatologie; Service d'Hépato-Gastroentérologie; Hôpital de la Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris; 47-83 boulevard de l'Hôpital 75013 Paris France
| | - Marika Rudler
- Brain-Liver Pitié-Salpêtrière Study Group (BLIPS); Hôpital de la Pitié-Salpêtrière; Assistance Publique-Hôpitaux de Paris; INSERM UMR_S 938, CDR Saint-Antoine & Institut de Cardiométabolisme et Nutrition (ICAN); 47-83 boulevard de l'Hôpital 75013 Paris France
- UPMC Univ Paris 06 & Soins Intensifs d'Hépatologie; Service d'Hépato-Gastroentérologie; Hôpital de la Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris; 47-83 boulevard de l'Hôpital 75013 Paris France
| | - Françoise Imbert-Bismut
- Brain-Liver Pitié-Salpêtrière Study Group (BLIPS); Hôpital de la Pitié-Salpêtrière; Assistance Publique-Hôpitaux de Paris; INSERM UMR_S 938, CDR Saint-Antoine & Institut de Cardiométabolisme et Nutrition (ICAN); 47-83 boulevard de l'Hôpital 75013 Paris France
- Service de biochimie; Hôpital de la Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris; 47-83 boulevard de l'Hôpital 75013 Paris France
| | - Dominique Thabut
- Brain-Liver Pitié-Salpêtrière Study Group (BLIPS); Hôpital de la Pitié-Salpêtrière; Assistance Publique-Hôpitaux de Paris; INSERM UMR_S 938, CDR Saint-Antoine & Institut de Cardiométabolisme et Nutrition (ICAN); 47-83 boulevard de l'Hôpital 75013 Paris France
- UPMC Univ Paris 06 & Soins Intensifs d'Hépatologie; Service d'Hépato-Gastroentérologie; Hôpital de la Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris; 47-83 boulevard de l'Hôpital 75013 Paris France
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Abstract
Acute on chronic liver failure (ACLF) was first described in 1995 as a clinical syndrome distinct to classic acute decompensation. Characterized by complications of decompensation, ACLF occurs on a background of chronic liver dysfunction and is associated with high rates of organ failure and significant short-term mortality estimated between 45% and 90%. Despite the clinical relevance of the condition, it still remains largely undefined with continued disagreement regarding its precise etiological factors, clinical course, prognostic criteria and management pathways. It is concerning that, despite our relative lack of understanding of the condition, the burden of ACLF among cirrhotic patients remains significant with an estimated prevalence of 30.9%. This paper highlights our current understanding of ACLF, including its etiology, diagnostic and prognostic criteria and pathophysiology. It is evident that further refinement of the ACLF classification system is required in order to detect high-risk patients and improve short-term mortality rates. The field of metabolomics certainly warrants investigation to enhance diagnostic and prognostic parameters, while the use of granulocyte-colony stimulating factor is a promising future therapeutic intervention for patients with ACLF.
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Affiliation(s)
- Azeem Alam
- Anaesthetics, Pain Medicine and Intensive Care, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, Chelsea & Westminster Hospital, London, SW7 2AZ, UK
| | - Ka Chun Suen
- Anaesthetics, Pain Medicine and Intensive Care, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, Chelsea & Westminster Hospital, London, SW7 2AZ, UK
| | - Daqing Ma
- Anaesthetics, Pain Medicine and Intensive Care, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, Chelsea & Westminster Hospital, London, SW7 2AZ, UK
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21
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Holecek M, Vodenicarovova M, Siman P. Acute effects of phenylbutyrate on glutamine, branched-chain amino acid and protein metabolism in skeletal muscles of rats. Int J Exp Pathol 2017. [PMID: 28621016 DOI: 10.1111/iep.12231] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Phenylbutyrate (PB) acts as chemical chaperone and histone deacetylase inhibitor, which is used to decrease ammonia in urea cycle disorders and has been investigated for use in the treatment of a number of lethal illnesses. We performed in vivo and in vitro experiments to examine the effects of PB on glutamine (GLN), branched-chain amino acid (BCAA; valine, leucine and isoleucine) and protein metabolism in rats. In the first study, animals were sacrificed one hour after three injections of PB (300mg/kg b.w.) or saline. In the second study, soleus (SOL, slow twitch) and extensor digitorum longus (EDL, fast twitch) muscles were incubated in a medium with or without PB (5 mM). L-[1-14 C] leucine was used to estimate protein synthesis and leucine oxidation, and 3-methylhistidine release was used to evaluate myofibrillar protein breakdown. PB treatment decreased GLN, BCAA and branched-chain keto acids (BCKAs) in blood plasma, decreased BCAA and increased GLN concentrations in muscles, and increased GLN synthetase activities in muscles. Addition of PB to incubation medium increased leucine oxidation (55% in EDL, 29% in SOL), decreased BCKA and increased GLN in medium of both muscles, increased GLN in muscles, decreased protein synthesis in SOL and increased proteolysis in EDL. It is concluded that PB decreases BCAA, BCKA and GLN in blood plasma, activates BCAA catabolism and GLN synthesis in muscle and exerts adverse effects on protein metabolism. The results indicate that BCAA and GLN supplementation is needed when PB is used therapeutically and that PB may be a useful prospective agent which could be effective in management of maple syrup urine disease.
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Affiliation(s)
- Milan Holecek
- Department of Physiology, Faculty of Medicine, Charles University, Hradec Kralove, Czech Republic
| | - Melita Vodenicarovova
- Department of Physiology, Faculty of Medicine, Charles University, Hradec Kralove, Czech Republic
| | - Pavel Siman
- Department of Biochemistry, Faculty of Medicine, Charles University, Hradec Kralove, Czech Republic
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22
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Hadjihambi A, De Chiara F, Hosford PS, Habtetion A, Karagiannis A, Davies N, Gourine AV, Jalan R. Ammonia mediates cortical hemichannel dysfunction in rodent models of chronic liver disease. Hepatology 2017; 65:1306-1318. [PMID: 28066916 PMCID: PMC5396295 DOI: 10.1002/hep.29031] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 11/22/2016] [Accepted: 12/23/2016] [Indexed: 12/19/2022]
Abstract
UNLABELLED The pathogenesis of hepatic encephalopathy (HE) in cirrhosis is multifactorial and ammonia is thought to play a key role. Astroglial dysfunction is known to be present in HE. Astrocytes are extensively connected by gap junctions formed of connexins, which also exist as functional hemichannels allowing exchange of molecules between the cytoplasm and the extracellular milieu. The astrocyte-neuron lactate shuttle hypothesis suggests that neuronal activity is fueled (at least in part) by lactate provided by neighboring astrocytes. We hypothesized that in HE, astroglial dysfunction could impair metabolic communication between astrocytes and neurons. In this study, we determined whether hyperammonemia leads to hemichannel dysfunction and impairs lactate transport in the cerebral cortex using rat models of HE (bile duct ligation [BDL] and induced hyperammonemia) and also evaluated the effect of ammonia-lowering treatment (ornithine phenylacetate [OP]). Plasma ammonia concentration in BDL rats was significantly reduced by OP treatment. Biosensor recordings demonstrated that HE is associated with a significant reduction in both tonic and hypoxia-induced lactate release in the cerebral cortex, which was normalized by OP treatment. Cortical dye loading experiments revealed hemichannel dysfunction in HE with improvement following OP treatment, while the expression of key connexins was unaffected. CONCLUSION The results of the present study demonstrate that HE is associated with central nervous system hemichannel dysfunction, with ammonia playing a key role. The data provide evidence of a potential neuronal energy deficit due to impaired hemichannel-mediated lactate transport between astrocytes and neurons as a possible mechanism underlying pathogenesis of HE. (Hepatology 2017;65:1306-1318).
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Affiliation(s)
- Anna Hadjihambi
- UCL Institute for Liver and Digestive Health, Division of Medicine, UCL Medical School, Royal Free HospitalRowland Hill StreetLondonUnited Kingdom,Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and PharmacologyUniversity College LondonLondonUnited Kingdom
| | - Francesco De Chiara
- UCL Institute for Liver and Digestive Health, Division of Medicine, UCL Medical School, Royal Free HospitalRowland Hill StreetLondonUnited Kingdom
| | - Patrick S. Hosford
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and PharmacologyUniversity College LondonLondonUnited Kingdom
| | - Abeba Habtetion
- UCL Institute for Liver and Digestive Health, Division of Medicine, UCL Medical School, Royal Free HospitalRowland Hill StreetLondonUnited Kingdom
| | | | - Nathan Davies
- UCL Institute for Liver and Digestive Health, Division of Medicine, UCL Medical School, Royal Free HospitalRowland Hill StreetLondonUnited Kingdom
| | - Alexander V. Gourine
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and PharmacologyUniversity College LondonLondonUnited Kingdom
| | - Rajiv Jalan
- UCL Institute for Liver and Digestive Health, Division of Medicine, UCL Medical School, Royal Free HospitalRowland Hill StreetLondonUnited Kingdom
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Jalan R. Novel therapies in the management of acute episodes of hepatic encephalopathy. Clin Liver Dis (Hoboken) 2017; 9:66-68. [PMID: 30992961 PMCID: PMC6467145 DOI: 10.1002/cld.620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Revised: 01/01/2017] [Accepted: 01/09/2017] [Indexed: 02/04/2023] Open
Affiliation(s)
- Rajiv Jalan
- Liver Failure Group, Institute for Liver and Digestive HealthUniversity College LondonLondonUnited Kingdom
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24
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Rackayova V, Braissant O, McLin VA, Berset C, Lanz B, Cudalbu C. 1H and 31P magnetic resonance spectroscopy in a rat model of chronic hepatic encephalopathy: in vivo longitudinal measurements of brain energy metabolism. Metab Brain Dis 2016; 31:1303-1314. [PMID: 26253240 DOI: 10.1007/s11011-015-9715-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 07/26/2015] [Indexed: 12/21/2022]
Abstract
Chronic liver disease (CLD) leads to a spectrum of neuropsychiatric disorders named hepatic encephalopathy (HE). Even though brain energy metabolism is believed to be altered in chronic HE, few studies have explored energy metabolism in CLD-induced HE, and their findings were inconsistent. The aim of this study was to characterize for the first time in vivo and longitudinally brain metabolic changes in a rat model of CLD-induced HE with a focus on energy metabolism, using the methodological advantages of high field proton and phosphorus Magnetic Resonance Spectroscopy (1H- and 31P-MRS). Wistar rats were bile duct ligated (BDL) and studied before BDL and at post-operative weeks 4 and 8. Glutamine increased linearly over time (+146 %) together with plasma ammonium (+159 %). As a compensatory effect, other brain osmolytes decreased: myo-inositol (-36 %), followed by total choline and creatine. A decrease in the neurotransmitters glutamate (-17 %) and aspartate (-28 %) was measured only at week 8, while no significant changes were observed for lactate and phosphocreatine. Among the other energy metabolites measured by 31P-MRS, we observed a non-significant decrease in ATP together with a significant decrease in ADP (-28 %), but only at week 8 after ligation. Finally, brain glutamine showed the strongest correlations with changes in other brain metabolites, indicating its importance in type C HE. In conclusion, mild alterations in some metabolites involved in energy metabolism were observed but only at the end stage of the disease when edema and neurological changes are already present. Therefore, our data indicate that impaired energy metabolism is not one of the major causes of early HE symptoms in the established model of type C HE.
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Affiliation(s)
- Veronika Rackayova
- Laboratory of Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Olivier Braissant
- Service of Biomedicine, University Hospital of Lausanne, Lausanne, Switzerland
| | - Valérie A McLin
- Swiss Center for Liver Disease in Children, Department of Pediatrics, University Hospitals Geneva, Geneva, Switzerland
| | - Corina Berset
- Centre d'Imagerie Biomedicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Bernard Lanz
- Laboratory of Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Cristina Cudalbu
- Centre d'Imagerie Biomedicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
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Kristiansen RG. Current state of knowledge of hepatic encephalopathy (part I): newer treatment strategies for hyperammonemia in liver failure. Metab Brain Dis 2016; 31:1357-1358. [PMID: 27651377 DOI: 10.1007/s11011-016-9908-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 09/05/2016] [Indexed: 01/27/2023]
Abstract
Alterations in interorgan metabolism of ammonia play an important role in the onset of hyperammonemia in liver failure. Glutamine synthetase (GS) in muscle is an important target for ammonia removal strategies in hyperammonemia. Ornithine Phenylacetate (OP) is hypothesized to remove ammonia by providing glutamate as a substrate for increased GS activity and hence glutamine production. The newly generated glutamine conjugates with phenylacetate forming phenylacetylglutamine which can be excreted in the urine, providing an excretion pathway for ammonia. We have also shown that OP targets glycine metabolism, providing an additional ammonia reducing effect.
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Affiliation(s)
- Rune Gangsoy Kristiansen
- Department of Anesthesiology, Anesthesia and Critical Care Research Group, University Hospital of North Norway, UiT-The Arctic University of Norway, Tromsø, Norway.
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Milewski K, Oria M. What we know: the inflammatory basis of hepatic encephalopathy. Metab Brain Dis 2016; 31:1239-1247. [PMID: 26497651 DOI: 10.1007/s11011-015-9740-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 09/24/2015] [Indexed: 02/07/2023]
Abstract
Central Nervous System (CNS) degeneration appearing in patients with cirrhosis is responsible for cognitive and persistent motor impairments that lead to an important impact on life quality. Brain injury affects certain areas of the CNS that might affect two types of cells: neurons and astrocytes. The process leading to brain injury could be induced by portosystemic shunting accompanied by hyperammonemia and by the activation of peripheral inflammation, manifested as episodic encephalopathy. Hyperammonemia combined with a decrease on the BCA/AAA ratio induces alterations of energetic metabolism and the formation of free radicals in the CNS. This process would be stimulated by the activation of peripheral inflammatory mediators that could act on receptors of the blood brain barrier such as TLR4, activating inflammatory responses in the CNS. As a result, a persistent activation of microglia and an irreversible neuronal and astrocytic injury would be induced. A new knowledge of the mechanisms leading to brain injury in cirrhosis would develop protective strategies to correct changes of nitrogen metabolism and inflammation.
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Affiliation(s)
- K Milewski
- Department of Neurotoxicology, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawińskiego 5 Str, 02-106, Warsaw, Poland
| | - M Oria
- Translational Research in Fetal Surgery for Congenital Malformations, Center for Fetal, Cellular and Molecular Therapy, Division of Pediatric General and Thoracic Surgery, Cincinnati Children's Hospital Medical Center (CCHMC), 3333 Burnet Avenue, MLC 11020, S 8.400 AT, Cincinnati, OH, 45229-3039, USA.
- Liver Failure Group, UCL Institute for Liver and Digestive Health, Royal Free Hospital, University College London, London, UK.
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Kristiansen RG, Rose CF, Ytrebø LM. Glycine and hyperammonemia: potential target for the treatment of hepatic encephalopathy. Metab Brain Dis 2016; 31:1269-1273. [PMID: 27339764 DOI: 10.1007/s11011-016-9858-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 06/12/2016] [Indexed: 01/10/2023]
Abstract
Hepatic encephalopathy (HE) is a neuropsychiatric disorder caused by hepatic dysfunction. Numerous studies dictate that ammonia plays an important role in the pathogenesis of HE, and hyperammonemia can lead to alterations in amino acid homeostasis. Glutamine and glycine are both ammoniagenic amino acids that are increased in liver failure. Modulating the levels of glutamine and glycine has shown to reduce ammonia concentration in hyperammonemia. Ornithine Phenylacetate (OP) has consistently been shown to reduce arterial ammonia levels in liver failure by modulating glutamine levels. In addition to this, OP has also been found to modulate glycine concentration providing an additional ammonia removing effect. Data support that glycine also serves an important role in N-methyl D-aspartate (NMDA) receptor mediated neurotransmission in HE. This potential important role for glycine in the pathogenesis of HE merits further investigations.
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Affiliation(s)
- Rune Gangsøy Kristiansen
- Department of Anesthesiology, Anesthesia and Critical Care Research Group, University Hospital of North Norway and UiT-The Arctic University of Norway, Tromsø, Norway.
- Department of Anesthesiology, Ålesund Hospital, Helse Møre og Romsdal, 6010, Ålesund, Norway.
| | - Christopher F Rose
- Hepato-Neuro Laboratory, CRCHUM, Université de Montréal, Montréal, QC, Canada
| | - Lars Marius Ytrebø
- Department of Anesthesiology, Anesthesia and Critical Care Research Group, University Hospital of North Norway and UiT-The Arctic University of Norway, Tromsø, Norway
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Holecek M, Vodenicarovova M. Phenylbutyrate exerts adverse effects on liver regeneration and amino acid concentrations in partially hepatectomized rats. Int J Exp Pathol 2016; 97:278-84. [PMID: 27381898 DOI: 10.1111/iep.12190] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 03/24/2016] [Indexed: 11/29/2022] Open
Abstract
Phenylbutyrate is recommended in urea cycle disorders and liver injury to enhance nitrogen disposal by the urine. However, hypothetically there may be adverse responses to the use of phenylbutyrate in the treatment of liver disease because of its role as a histone deacetylase inhibitor and its stimulatory effect on branched-chain alpha-keto acid dehydrogenase, the rate-limiting enzyme in the catabolism of branched-chain amino acids (BCAA; valine, leucine and isoleucine). We report the effects of phenylbutyrate on liver regeneration and amino acid levels in plasma of partially hepatectomized (PH) rats. Phenylbutyrate or saline was administered at 12-h intervals to PH or laparotomized rats. Phenylbutyrate delayed the onset of liver regeneration compared to the saline-treated controls, as indicated by lower hepatic DNA specific activities 18 and 24( ) h post-PH, decreased hepatic fractional protein synthesis rates 24 h post-PH and lowered the increases in liver weights and hepatic protein and DNA contents 48 h after PH. Hepatic DNA fragmentation (a hallmark of apoptosis) was higher in the phenylbutyrate-treated animals than in controls. Phenylbutyrate decreased the glutamine and BCAA concentrations and the ratio of the BCAA to aromatic amino acids (phenylalanine and tyrosine) in the blood plasma in both hepatectomized and laparotomized animals. In conclusion, the delayed onset of liver regeneration and the decrease in BCAA/AAA ratio in blood suggest that phenylbutyrate administration may be disastrous in subjects with acute hepatic injury and BCAA supplementation is needed when phenylbutyrate is used therapeutically.
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Affiliation(s)
- Milan Holecek
- Department of Physiology, Faculty of Medicine in Hradec Kralove, Charles University in Prague, Hradec Kralove, Czech Republic
| | - Melita Vodenicarovova
- Department of Physiology, Faculty of Medicine in Hradec Kralove, Charles University in Prague, Hradec Kralove, Czech Republic
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Jalan R, De Chiara F, Balasubramaniyan V, Andreola F, Khetan V, Malago M, Pinzani M, Mookerjee RP, Rombouts K. Ammonia produces pathological changes in human hepatic stellate cells and is a target for therapy of portal hypertension. J Hepatol 2016; 64:823-33. [PMID: 26654994 DOI: 10.1016/j.jhep.2015.11.019] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 11/09/2015] [Accepted: 11/11/2015] [Indexed: 12/14/2022]
Abstract
BACKGROUND & AIMS Hepatic stellate cells (HSCs) are vital to hepatocellular function and the liver response to injury. They share a phenotypic homology with astrocytes that are central in the pathogenesis of hepatic encephalopathy, a condition in which hyperammonemia plays a pathogenic role. This study tested the hypothesis that ammonia modulates human HSC activation in vitro and in vivo, and evaluated whether ammonia lowering, by using l-ornithine phenylacetate (OP), modifies HSC activation in vivo and reduces portal pressure in a bile duct ligation (BDL) model. METHODS Primary human HSCs were isolated and cultured. Proliferation (BrdU), metabolic activity (MTS), morphology (transmission electron, light and immunofluorescence microscopy), HSC activation markers, ability to contract, changes in oxidative status (ROS) and endoplasmic reticulum (ER) were evaluated to identify effects of ammonia challenge (50 μM, 100 μM, 300 μM) over 24-72 h. Changes in plasma ammonia levels, markers of HSC activation, portal pressure and hepatic eNOS activity were quantified in hyperammonemic BDL animals, and after OP treatment. RESULTS Pathophysiological ammonia concentrations caused significant and reversible changes in cell proliferation, metabolic activity and activation markers of hHSC in vitro. Ammonia also induced significant alterations in cellular morphology, characterised by cytoplasmic vacuolisation, ER enlargement, ROS production, hHSC contraction and changes in pro-inflammatory gene expression together with HSC-related activation markers such as α-SMA, myosin IIa, IIb, and PDGF-Rβ. Treatment with OP significantly reduced plasma ammonia (BDL 199.1 μmol/L±43.65 vs. BDL+OP 149.27 μmol/L±51.1, p<0.05) and portal pressure (BDL 14±0.6 vs. BDL+OP 11±0.3 mmHg, p<0.01), which was associated with increased eNOS activity and abrogation of HSC activation markers. CONCLUSIONS The results show for the first time that ammonia produces deleterious morphological and functional effects on HSCs in vitro. Targeting ammonia with the ammonia lowering drug OP reduces portal pressure and deactivates hHSC in vivo, highlighting the opportunity for evaluating ammonia lowering as a potential therapy in cirrhotic patients with portal hypertension.
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Affiliation(s)
- Rajiv Jalan
- Liver Failure Group, Institute for Liver & Digestive Health, University College of London, Royal Free, London, UK
| | - Francesco De Chiara
- Liver Failure Group, Institute for Liver & Digestive Health, University College of London, Royal Free, London, UK
| | - Vairappan Balasubramaniyan
- Liver Failure Group, Institute for Liver & Digestive Health, University College of London, Royal Free, London, UK
| | - Fausto Andreola
- Liver Failure Group, Institute for Liver & Digestive Health, University College of London, Royal Free, London, UK
| | - Varun Khetan
- Liver Failure Group, Institute for Liver & Digestive Health, University College of London, Royal Free, London, UK
| | - Massimo Malago
- Division of Surgery, University College London, Royal Free, London, UK
| | - Massimo Pinzani
- Regenerative Medicine & Fibrosis Group, Institute for Liver & Digestive Health, University College London, Royal Free, London, UK
| | - Rajeshwar P Mookerjee
- Liver Failure Group, Institute for Liver & Digestive Health, University College of London, Royal Free, London, UK.
| | - Krista Rombouts
- Regenerative Medicine & Fibrosis Group, Institute for Liver & Digestive Health, University College London, Royal Free, London, UK.
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Abstract
Acute-on-chronic liver failure combines an acute deterioration in liver function in an individual with pre-existing chronic liver disease and hepatic and extrahepatic organ failures, and is associated with substantial short-term mortality. Common precipitants include bacterial and viral infections, alcoholic hepatitis, and surgery, but in more than 40% of patients, no precipitating event is identified. Systemic inflammation and susceptibility to infection are characteristic pathophysiological features. A new diagnostic score, the Chronic Liver Failure Consortium (CLIF-C) organ failure score, has been developed for classification and prognostic assessment of patients with acute-on-chronic liver failure. Disease can be reversed in many patients, and thus clinical management focuses upon the identification and treatment of the precipitant while providing multiorgan-supportive care that addresses the complex pattern of physiological disturbance in critically ill patients with liver disease. Liver transplantation is a highly effective intervention in some specific cases, but recipient identification, organ availability, timing of transplantation, and high resource use are barriers to more widespread application. Recognition of acute-on-chronic liver failure as a clinically and pathophysiologically distinct syndrome with defined diagnostic and prognostic criteria will help to encourage the development of new management pathways and interventions to address the unacceptably high mortality.
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Affiliation(s)
- William Bernal
- Liver Intensive Therapy Unit, King's College Hospital, London, UK.
| | - Rajiv Jalan
- Liver Failure Group, Division of Medicine, University College London, London, UK; Institute for Liver and Digestive Health, Division of Medicine, University College London, London, UK; Sheila Sherlock Liver Centre, Royal Free Hospital, London, UK
| | - Alberto Quaglia
- Histopathology Section, Institute of Liver Studies, King's College Hospital, London, UK
| | - Kenneth Simpson
- Department of Hepatology, University of Edinburgh, Edinburgh, UK
| | - Julia Wendon
- Liver Intensive Therapy Unit, King's College Hospital, London, UK
| | - Andrew Burroughs
- Institute for Liver and Digestive Health, Division of Medicine, University College London, London, UK; Sheila Sherlock Liver Centre, Royal Free Hospital, London, UK
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31
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Dabos KJ, Parkinson JA, Sadler IH, Plevris JN, Hayes PC. 1H nuclear magnetic resonance spectroscopy-based metabonomic study in patients with cirrhosis and hepatic encephalopathy. World J Hepatol 2015; 7:1701-1707. [PMID: 26140090 PMCID: PMC4483552 DOI: 10.4254/wjh.v7.i12.1701] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 05/09/2015] [Accepted: 06/08/2015] [Indexed: 02/06/2023] Open
Abstract
AIM: To identify plasma metabolites used as biomarkers in order to distinguish cirrhotics from controls and encephalopathics.
METHODS: A clinical study involving stable cirrhotic patients with and without overt hepatic encephalopathy was designed. A control group of healthy volunteers was used. Plasma from those patients was analysed using 1H - nuclear magnetic resonance spectroscopy. We used the Carr Purcell Meiboom Gill sequence to process the sample spectra at ambient probe temperature. We used a gated secondary irradiation field for water signal suppression. Samples were calibrated and referenced using the sodium trimethyl silyl propionate peak at 0.00 ppm. For each sample 128 transients (FID’s) were acquired into 32 K complex data points over a spectral width of 6 KHz. 30 degree pulses were applied with an acquisition time of 4.0 s in order to achieve better resolution, followed by a recovery delay of 12 s, to allow for complete relaxation and recovery of the magnetisation. A metabolic profile was created for stable cirrhotic patients without signs of overt hepatic encephalopathy and encephalopathic patients as well as healthy controls. Stepwise discriminant analysis was then used and discriminant factors were created to differentiate between the three groups.
RESULTS: Eighteen stabled cirrhotic patients, eighteen patients with overt hepatic encephalopathy and seventeen healthy volunteers were recruited. Patients with cirrhosis had significantly impaired ketone body metabolism, urea synthesis and gluconeogenesis. This was demonstrated by higher concentrations of acetoacetate (0.23 ± 0.02 vs 0.05 ± 0.00, P < 0.01), and b-hydroxybutarate (0.58 ± 0.14 vs 0.08 ± 0.00, P < 0.01), lower concentrations of glutamine (0.44 ± 0.08 vs 0.63 ± 0.03, P < 0.05), histidine (0.16 ± 0.01 vs 0.36 ± 0.04, P < 0.01) and arginine (0.08 ± 0.01 vs 0.14 ± 0.02, P < 0.03) and higher concentrations of glutamate (1.36 ± 0.25 vs 0.58 ± 0.04, P < 0.01), lactate (1.53 ± 0.11 vs 0.42 ± 0.05, P < 0.01), pyruvate (0.11 ± 0.02 vs 0.03 ± 0.00, P < 0.01) threonine (0.39 ± 0.02 vs 0.08 ± 0.01, P < 0.01) and aspartate (0.37 ± 0.03 vs 0.03 ± 0.01). A five metabolite signature by stepwise discriminant analysis could separate between controls and cirrhotic patients with an accuracy of 98%. In patients with encephalopathy we observed further derangement of ketone body metabolism, impaired production of glycerol and myoinositol, reversal of Fischer’s ratio and impaired glutamine production as demonstrated by lower b-hydroxybutyrate (0.58 ± 0.14 vs 0.16 ± 0.02, P < 0.0002), higher acetoacetate (0.23 ± 0.02 vs 0.41 ± 0.16, P < 0.05), leucine (0.33 ± 0.02 vs 0.49 ± 0.05, P < 0.005) and isoleucine (0.12 ± 0.02 vs 0.27 ± 0.02, P < 0.0004) and lower glutamine (0.44 ± 0.08 vs 0.36 ± 0.04, P < 0.013), glycerol (0.53 ± 0.03 vs 0.19 ± 0.02, P < 0.000) and myoinositol (0.36 ± 0.04 vs 0.18 ± 0.02, P < 0.010) concentrations. A four metabolite signature by stepwise discriminant analysis could separate between encephalopathic and cirrhotic patients with an accuracy of 87%.
CONCLUSION: Patients with cirrhosis and patients with hepatic encephalopathy exhibit distinct metabolic abnormalities and the use of metabonomics can select biomarkers for these diseases.
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Vairappan B. Endothelial dysfunction in cirrhosis: Role of inflammation and oxidative stress. World J Hepatol 2015; 7:443-459. [PMID: 25848469 PMCID: PMC4381168 DOI: 10.4254/wjh.v7.i3.443] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 11/08/2014] [Accepted: 12/01/2014] [Indexed: 02/06/2023] Open
Abstract
This review describes the recent developments in the pathobiology of endothelial dysfunction (ED) in the context of cirrhosis with portal hypertension and defines novel strategies and potential targets for therapy. ED has prognostic implications by predicting unfavourable early hepatic events and mortality in patients with portal hypertension and advanced liver diseases. ED characterised by an impaired bioactivity of nitric oxide (NO) within the hepatic circulation and is mainly due to decreased bioavailability of NO and accelerated degradation of NO with reactive oxygen species. Furthermore, elevated inflammatory markers also inhibit NO synthesis and causes ED in cirrhotic liver. Therefore, improvement of NO availability in the hepatic circulation can be beneficial for the improvement of endothelial dysfunction and associated portal hypertension in patients with cirrhosis. Furthermore, therapeutic agents that are identified in increasing NO bioavailability through improvement of hepatic endothelial nitric oxide synthase (eNOS) activity and reduction in hepatic asymmetric dimethylarginine, an endogenous modulator of eNOS and a key mediator of elevated intrahepatic vascular tone in cirrhosis would be interesting therapeutic approaches in patients with endothelial dysfunction and portal hypertension in advanced liver diseases.
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Shalimar, Acharya SK. Management in acute liver failure. J Clin Exp Hepatol 2015; 5:S104-15. [PMID: 26041950 PMCID: PMC4442864 DOI: 10.1016/j.jceh.2014.11.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 11/26/2014] [Indexed: 12/12/2022] Open
Abstract
Acute liver failure (ALF) is a rare, potentially fatal complication of severe hepatic illness resulting from various causes. In a clinical setting, severe hepatic injury is usually recognised by the appearance of jaundice, encephalopathy and coagulopathy. The central and most important clinical event in ALF is occurrence of hepatic encephalopathy (HE) and cerebral edema which is responsible for most of the fatalities in this serious clinical syndrome. The pathogenesis of encephalopathy and cerebral edema in ALF is unique and multifactorial. Ammonia plays a central role in the pathogenesis. The role of newer ammonia lowering agents is still evolving. Liver transplant is the only effective therapy that has been identified to be of promise in those with poor prognostic factors, whereas in the others, aggressive intensive medical management has been documented to salvage a substantial proportion of patients. A small fraction of patients undergo liver transplant and the remaining are usually treated with medical therapy. Therefore, identification of the complications and causes of death in such patients, and use of appropriate prognostic models to identify those who need liver transplant and those who can be managed with medical treatment is a vital component of therapeutic strategy. In this review, we discuss the various pathogenetic mechanisms and treatment options available.
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Key Words
- AASLD, American Association For the Study of Liver
- ALF, Acute Liver Failure
- ALFED, Acute Liver Failure Early Dynamic Model
- BBB, Blood Brain Barrier
- BCAA, Branched Chain Amino acid
- CBF, Cerebral Blood Flow
- CPP, Cerebral Perfusion Pressure
- CVVHD, Continuous Veno-Venous Hemodialysis
- FFP, Fresh Frozen Plasma
- GM-CSF, Granulocyte Macrophage Colony Stimulating Factor
- HE, Hepatic Encephalopathy
- ICU, Intensive Care Unit
- IEI, Icterus Encephalopathy Interval
- IL-1β, Interleukin-1 beta
- IL6, Interlekin 6
- INR, International Normalized Ratio
- LOLA, l-Ornithine L Aspartate
- LOPA
- LOPA, l-Ornithine Phenyl Acetate
- MAP, Mean Arterial Pressure
- NAC, N-Acetyl Cysteine
- NO, Nitric Oxide
- OLT, Orthotopic Liver Transplantation
- PCWP, Pulmonary Capillary Wedge Pressure
- PEEP, Positive End Expiratory Pressure
- PT, Prothrombin Time
- SIMV, Synchronous Intermittent mandatory Ventilation
- SIRS, Systemic Inflammatory Response Syndrome
- SPEAR, Selective Parenteral and Enteral Antibiotic Regimen
- TNF-α, Tumor Necrosis Factor alfa
- UCD, Urea Cycle Disorder
- USALF, United States Acute liver Failure Study Group
- ammonia
- cerebral edema
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Affiliation(s)
| | - Subrat K. Acharya
- Address for correspondence: Subrat K. Acharya, Department of Gastroenterology, All India Institute of Medical Sciences, New Delhi 110029, India.
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Wright G, Sharifi Y, Jover-Cobos M, Jalan R. The brain in acute on chronic liver failure. Metab Brain Dis 2014; 29:965-73. [PMID: 24838253 PMCID: PMC4234892 DOI: 10.1007/s11011-014-9553-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 04/22/2014] [Indexed: 12/30/2022]
Abstract
Acute-on-chronic liver failure (ACLF) is a newly defined clinical entity with significant morbidity and mortality (~40-90% at 1 year dependent on need for organ support at presentation). It defines a presentation with acute severe liver injury, often with multiorgan dysfunction, on a background of previously known or unknown cirrhosis. In its severest form, it is almost indistinguishable from acute liver failure, as similarly in around 5% may rapidly progress to intracranial hypertension and cerebral oedema culminating in coma and/or death. Our understanding of such cerebral sequelae is currently limited to clinical observation, though our knowledge base is rapidly expanding since recent consensus clinical definition and guidance. Moreover, there are now animal models of ACLF and imaging modalities to better characterize events in the brain that occur with ACLF. However, as yet there has been little in the way of interventional study of this condition which are much needed. In this review we dissect existing clinical and experimental data to better characterise the manifestations of ACLF on the brain and allow for the development of targeted therapy as currently the plethora of existing interventions were designed to treat either the effects of cirrhosis or acute liver injury independently.
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Affiliation(s)
- Gavin Wright
- Institute for Liver and Digestive Health, Liver Failure Group, UCL Institute of Hepatology, The Royal Free Hospital, Upper Third UCL Medical School, Pond Street, London, NW3 2PF UK
- Basildon & Thurrock University Hospitals NHS Foundation Trust Nethermayne, Essex, SS16 5NL Basildon UK
| | - Yalda Sharifi
- Institute for Liver and Digestive Health, Liver Failure Group, UCL Institute of Hepatology, The Royal Free Hospital, Upper Third UCL Medical School, Pond Street, London, NW3 2PF UK
| | - Maria Jover-Cobos
- Institute for Liver and Digestive Health, Liver Failure Group, UCL Institute of Hepatology, The Royal Free Hospital, Upper Third UCL Medical School, Pond Street, London, NW3 2PF UK
| | - Rajiv Jalan
- Institute for Liver and Digestive Health, Liver Failure Group, UCL Institute of Hepatology, The Royal Free Hospital, Upper Third UCL Medical School, Pond Street, London, NW3 2PF UK
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Abstract
INTRODUCTION Hepatic encephalopathy (HE) is a serious neuropsychiatric complication that is seen in patients with liver failure. The pathogenesis of HE is not entirely understood, but several hypotheses have emerged and persisted during the years. Despite the many prevalent hypotheses, most of the existing evidence point to ammonia as the main culprit behind primary and secondary symptoms making it the center of potential therapeutic options for the treatment of HE. Most treatments of hyperammonemia target the organs and metabolic processes involved in ammonia detoxification. AREAS COVERED This article provides a review of the current targets of therapy as well as the drugs used for hyperammonemia treatment. EXPERT OPINION Lactulose and rifaximin have a proven role as measures to use for secondary prophylaxis and are the mainstay of current therapy. The use of molecular adsorbent recirculating system in patients with severe HE has been proven to be efficacious, but through mechanisms that appear to be independent of ammonia. The main challenge that faces the further development of treatments for HE is finding appropriate end points, and the next step would be to provide evidence of the effectiveness of established treatments and define the role of emerging new treatments.
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Affiliation(s)
- Anna Hadjihambi
- UCL Institute for Liver and Digestive Health, UCL Medical School , Upper Third Floor, Royal Free Campus, Pond Street, NW3 2PF, London , UK +44 207 4332 794 ;
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Kristiansen RG, Rose CF, Fuskevåg OM, Mæhre H, Revhaug A, Jalan R, Ytrebø LM. L-Ornithine phenylacetate reduces ammonia in pigs with acute liver failure through phenylacetylglycine formation: a novel ammonia-lowering pathway. Am J Physiol Gastrointest Liver Physiol 2014; 307:G1024-31. [PMID: 25258408 DOI: 10.1152/ajpgi.00244.2014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Glycine is an important ammoniagenic amino acid, which is increased in acute liver failure (ALF). We have previously shown that L-ornithine phenylacetate (OP) attenuates ammonia rise and intracranial pressure in pigs suffering from ALF but failed to demonstrate a stoichiometric relationship between change in plasma ammonia levels and excretion of phenylacetylglutamine in urine. The aim was to investigate the impact of OP treatment on the phenylacetylglycine pathway as an alternative and additional ammonia-lowering pathway. A well-validated and -characterized large porcine model of ALF (portacaval anastomosis, followed by hepatic artery ligation), which recapitulates the cardinal features of human ALF, was used. Twenty-four female pigs were randomized into three groups: (1) sham operated + vehicle, (2) ALF + vehicle, and (3) ALF + OP. There was a significant increase in arterial glycine concentration in ALF (P < 0.001 compared with sham), with a three-fold increase in glycine release into the systemic circulation from the kidney compared with the sham group. This increase was attenuated in both the blood and brain of the OP-treated animals (P < 0.001 and P < 0.05, respectively), and the attenuation was associated with renal removal of glycine through excretion of the conjugation product phenylacetylglycine in urine (ALF + vehicle: 1,060 ± 106 μmol/l; ALF + OP: 27,625 ± 2,670 μmol/l; P < 0.003). Data from this study provide solid evidence for the existence of a novel, additional pathway for ammonia removal in ALF, involving glycine production and removal, which is targeted by OP.
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Affiliation(s)
- Rune Gangsøy Kristiansen
- Department of Anesthesiology, University Hospital of North Norway and UiT The Arctic University of Norway, Tromsø, Norway;
| | - Christopher F Rose
- Hepato-Neuro Laboratory, The University of Montreal Hospital Research Centre, Université de Montréal, Québec, Canada
| | - Ole-Martin Fuskevåg
- Department of Clinical Pharmacology, University Hospital of North Norway and UiT The Arctic University of Norway, Tromsø, Norway
| | - Hanne Mæhre
- Norwegian College of Fishery Science, UiT The Arctic University of Norway, Tromsø, Norway
| | - Arthur Revhaug
- Department of Digestive Surgery, University Hospital of North Norway and UiT The Arctic University of Norway, Tromsø, Norway; and
| | - Rajiv Jalan
- Liver Failure Group, University College London Institute for Liver and Digestive Health, Medical School, Royal Free Hospital, London, United Kingdom
| | - Lars Marius Ytrebø
- Department of Anesthesiology, University Hospital of North Norway and UiT The Arctic University of Norway, Tromsø, Norway
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Abstract
Human adults produce around 1000 mmol of ammonia daily. Some is reutilized in biosynthesis. The remainder is waste and neurotoxic. Eventually most is excreted in urine as urea, together with ammonia used as a buffer. In extrahepatic tissues, ammonia is incorporated into nontoxic glutamine and released into blood. Large amounts are metabolized by the kidneys and small intestine. In the intestine, this yields ammonia, which is sequestered in portal blood and transported to the liver for ureagenesis, and citrulline, which is converted to arginine by the kidneys. The amazing developments in NMR imaging and spectroscopy and molecular biology have confirmed concepts derived from early studies in animals and cell cultures. The processes involved are exquisitely tuned. When they are faulty, ammonia accumulates. Severe acute hyperammonemia causes a rapidly progressive, often fatal, encephalopathy with brain edema. Chronic milder hyperammonemia causes a neuropsychiatric illness. Survivors of severe neonatal hyperammonemia have structural brain damage. Proposed explanations for brain edema are an increase in astrocyte osmolality, generally attributed to glutamine accumulation, and cytotoxic oxidative/nitrosative damage. However, ammonia neurotoxicity is multifactorial, with disturbances also in neurotransmitters, energy production, anaplerosis, cerebral blood flow, potassium, and sodium. Around 90% of hyperammonemic patients have liver disease. Inherited defects are rare. They are being recognized increasingly in adults. Deficiencies of urea cycle enzymes, citrin, and pyruvate carboxylase demonstrate the roles of isolated pathways in ammonia metabolism. Phenylbutyrate is used routinely to treat inherited urea cycle disorders, and its use for hepatic encephalopathy is under investigation.
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Affiliation(s)
- Valerie Walker
- Department of Clinical Biochemistry, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom.
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Bosoi CR, Tremblay M, Rose CF. Induction of systemic oxidative stress leads to brain oedema in portacaval shunted rats. Liver Int 2014; 34:1322-9. [PMID: 25354203 DOI: 10.1111/liv.12414] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 11/16/2013] [Indexed: 12/13/2022]
Abstract
BACKGROUND & AIMS The pathogenesis of hepatic encephalopathy (HE) is multifactorial and often associated with the development of brain oedema. In addition to ammonia playing a central role, systemic oxidative stress is believed to aggravate the neuropsychological effects of ammonia in patients with chronic liver disease (CLD). The aim of this study was to (i) induce systemic oxidative stress in hyperammonaemic portacaval anastomosed (PCA) rats by inhibiting the antioxidant glutathione using Dimethyl maleate (DEM) and (ii) investigate whether a synergistic relationship between ammonia and oxidative stress contributes to the pathogenesis of brain oedema in CLD. METHODS Four-week PCA and sham-operated rats received DEM (0.4-4 mg/kg/day) for the last 10 days before sacrifice when oxidative stress markers [reactive oxygen species (ROS) and malondialdehyde (MDA)] were assessed in blood and frontal cortex. Brain water content was measured using a specific gravimetric technique. RESULTS Dimethyl maleate induced an increase in ROS and MDA in the blood, but not in the brain, of the PCA rats, compared with non-treated PCA rats. This was accompanied with an increase in brain water content (PCA+DEM: 78.45 ± 0.13% vs. PCA: 77.38 ± 0.11%, P < 0.001). Higher doses of DEM induced systemic oxidative stress in sham-operated controls, but brain oedema did not develop. CONCLUSIONS Dimethyl maleate provoked systemic, not central, oxidative stress in PCA rats, resulting in the development of brain oedema. Independently, hyperammonaemia and systemic oxidative stress do not precipitate brain oedema; therefore, our findings sustain that a synergistic effect between hyperammonaemia and systemic oxidative stress is responsible for the development of brain oedema in HE.
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Affiliation(s)
- Cristina R Bosoi
- Neuroscience Research Unit, Hôpital Saint-Luc (CRCHUM), Université de Montréal, Québec, Canada
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Hadjihambi A, Rose CF, Jalan R. Novel insights into ammonia-mediated neurotoxicity pointing to potential new therapeutic strategies. Hepatology 2014; 60:1101-3. [PMID: 24975882 DOI: 10.1002/hep.27282] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 06/06/2014] [Accepted: 06/25/2014] [Indexed: 01/31/2023]
Affiliation(s)
- Anna Hadjihambi
- Liver failure Group, Institute for Liver and Digestive Health, UCL Medical School, Royal Free Hospital, London, UK
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40
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Increased brain lactate is central to the development of brain edema in rats with chronic liver disease. J Hepatol 2014; 60:554-60. [PMID: 24512824 DOI: 10.1016/j.jhep.2013.10.011] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 10/04/2013] [Accepted: 10/11/2013] [Indexed: 01/12/2023]
Abstract
BACKGROUND & AIMS The pathogenesis of brain edema in patients with chronic liver disease (CLD) and minimal hepatic encephalopathy (HE) remains undefined. This study evaluated the role of brain lactate, glutamine and organic osmolytes, including myo-inositol and taurine, in the development of brain edema in a rat model of cirrhosis. METHODS Six-week bile-duct ligated (BDL) rats were injected with (13)C-glucose and de novo synthesis of lactate, and glutamine in the brain was quantified using (13)C nuclear magnetic resonance spectroscopy (NMR). Total brain lactate, glutamine, and osmolytes were measured using (1)H NMR or high performance liquid chromatography. To further define the interplay between lactate, glutamine and brain edema, BDL rats were treated with AST-120 (engineered activated carbon microspheres) and dichloroacetate (DCA: lactate synthesis inhibitor). RESULTS Significant increases in de novo synthesis of lactate (1.6-fold, p<0.001) and glutamine (2.2-fold, p<0.01) were demonstrated in the brains of BDL rats vs. SHAM-operated controls. Moreover, a decrease in cerebral myo-inositol (p<0.001), with no change in taurine, was found in the presence of brain edema in BDL rats vs. controls. BDL rats treated with either AST-120 or DCA showed attenuation in brain edema and brain lactate. These two treatments did not lead to similar reductions in brain glutamine. CONCLUSIONS Increased brain lactate, and not glutamine, is a primary player in the pathogenesis of brain edema in CLD. In addition, alterations in the osmoregulatory response may also be contributing factors. Our results suggest that inhibiting lactate synthesis is a new potential target for the treatment of HE.
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Jover-Cobos M, Noiret L, Lee K, Sharma V, Habtesion A, Romero-Gomez M, Davies N, Jalan R. Ornithine phenylacetate targets alterations in the expression and activity of glutamine synthase and glutaminase to reduce ammonia levels in bile duct ligated rats. J Hepatol 2014; 60:545-53. [PMID: 24512823 DOI: 10.1016/j.jhep.2013.10.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 10/07/2013] [Accepted: 10/08/2013] [Indexed: 12/21/2022]
Abstract
BACKGROUND & AIMS In liver failure, ammonia homeostasis is dependent upon the function of the ammonia metabolising enzymes, glutamine synthetase (GS) and glutaminase (GA) but data about their protein expression and activity are lacking. The aims of this study were to determine the protein expression and activity of GS and GA in individual organs in a rat model of chronic liver disease and to test whether the treatment with the ammonia-lowering agent ornithine phenylacetate (OP) modulates their activities. METHODS 49 SD rats were studied 35 days after sham-operation or bile duct ligation (BDL). The BDL group received: L-ornithine (0.6 mg/kg/day), Phenylacetate (0.6 mg/kg/day), OP (0.6 mg/kg/day) or placebo (saline) for 5 days prior to sacrifice. Arterial ammonia, amino acids and liver biochemistry were measured. Expressions of GS and GA were determined by Western-blotting and activities by end-point methods in liver, muscle, gut, kidney, lung, and frontal cortex. RESULTS In BDL rats, hepatic GS enzyme activity was reduced by more than 80% compared to sham rats. Further, in BDL rats GA activity was reduced in liver but increased in the gut, muscle and frontal cortex compared to sham rats. OP treatment resulted in a reduction in hyperammonemia in BDL rats, associated with increased GS activity in the muscle and reduced gut GA activity. CONCLUSIONS In a rat model of chronic liver failure, hyperammonemia is associated with inadequate compensation by liver and muscle GS activity and increased gut GA activity. OP reduces plasma ammonia by increasing GS in the muscle and reducing GA activity in the gut providing additional insights into its mechanism of its action. GS and GA may serve as important future therapeutic targets for hyperammonemia in liver failure.
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Affiliation(s)
- M Jover-Cobos
- Liver Failure Group, UCL Institute for Liver and Digestive Health, Royal Free Hospital Campus, University College of London (UCL), Pond Street, London, United Kingdom
| | - L Noiret
- Liver Failure Group, UCL Institute for Liver and Digestive Health, Royal Free Hospital Campus, University College of London (UCL), Pond Street, London, United Kingdom; COMPLEX CoMPLEX, UCL, Gower Street, London WC1E 6BT, United Kingdom
| | - K Lee
- Royal Veterinary College, Hatfield, Hertfordshire AL9 7TA, United Kingdom
| | - V Sharma
- Liver Failure Group, UCL Institute for Liver and Digestive Health, Royal Free Hospital Campus, University College of London (UCL), Pond Street, London, United Kingdom
| | - A Habtesion
- Liver Failure Group, UCL Institute for Liver and Digestive Health, Royal Free Hospital Campus, University College of London (UCL), Pond Street, London, United Kingdom
| | - M Romero-Gomez
- CIBEREHD, UCM Digestive Diseases, Valme University Hospital, Seville, Spain
| | - N Davies
- Liver Failure Group, UCL Institute for Liver and Digestive Health, Royal Free Hospital Campus, University College of London (UCL), Pond Street, London, United Kingdom
| | - R Jalan
- Liver Failure Group, UCL Institute for Liver and Digestive Health, Royal Free Hospital Campus, University College of London (UCL), Pond Street, London, United Kingdom.
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Sharma K, Pant S, Misra S, Dwivedi M, Misra A, Narang S, Tewari R, Bhadoria AS. Effect of rifaximin, probiotics, and l-ornithine l-aspartate on minimal hepatic encephalopathy: a randomized controlled trial. Saudi J Gastroenterol 2014; 20:225-32. [PMID: 25038208 PMCID: PMC4131305 DOI: 10.4103/1319-3767.136975] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND/AIMS Minimal hepatic encephalopathy (MHE) implies subtle impairment of cognitive functions in the absence of features of overt encephalopathy. We aimed to determine the prevalence of MHE in patients with liver cirrhosis and to find out the effect of rifaximin, probiotics, and l-ornithine l-aspartate (LOLA) individually in reversal of MHE by comparing it with placebo group. PATIENTS AND METHODS This study was carried out in two phases. Phase I included the recruitment of 250 apparently healthy controls and extraction of normative data utilizing three neuropsychometric tests (NPTs) and critical flicker frequency (CFF) test. Phase II consisted of screening and recruitment of patients of MHE followed by drugs trial. A total of 317 cirrhotics were screened; 111 were excluded and the remaining 206 cirrhotics were screened for MHE using NPTs and/or CFF test. Of these, 124 patients with MHE were randomized to receive LOLA (n = 31), rifaximin (n = 31), probiotics (n = 32), for 2 months and were compared with patients who were given placebo (n = 30). RESULTS Out of 206 cirrhotics, 124 (60.19%) had MHE. Among these 124 MHE patients, 87 (70.16%) patients had CFF <39Hz, 112 (90.32%) patients with MHE had two or more abnormal NPTs, and 75 (60.48%) patients had abnormality on both the CFF values and more than two abnormal NPTs. Intention-to-treat analysis showed the number of patients who improved after giving treatment were 67.7% (21/31), 70.9% (22/31), 50% (16/32), and 30% (9/30) for LOLA, rifaximin, probiotics, and placebo, respectively. CFF scores and improvement in psychometric tests after treatment were significantly higher (P < 0.05) for LOLA, rifaximin, and probiotics as compared with placebo group. CONCLUSIONS Prevalence of MHE is high in patients with cirrhosis of liver. Rifaximin, LOLA, and probiotics are better than giving placebo in patients with MHE.
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Affiliation(s)
- Kapil Sharma
- Department of Hepatology, Institute of Liver and Biliary Sciences, New Delhi, India,Address for correspondence: Dr. Kapil Sharma, Department of Hepatology, Institute of Liver and Biliary Sciences, D-1, Vasant Kunj, New Delhi – 110 070, India. E-mail:
| | - Sanjay Pant
- Department of Gastroenterology and Hepatology, Moti Lal Nehru Medical College, Allahabad, Uttar Pradesh, India
| | - Sriprakash Misra
- Department of Gastroenterology and Hepatology, Moti Lal Nehru Medical College, Allahabad, Uttar Pradesh, India
| | - Manisha Dwivedi
- Department of Gastroenterology and Hepatology, Moti Lal Nehru Medical College, Allahabad, Uttar Pradesh, India
| | - Alok Misra
- Department of Gastroenterology and Hepatology, Moti Lal Nehru Medical College, Allahabad, Uttar Pradesh, India
| | - Sushil Narang
- Department of Gastroenterology and Hepatology, Moti Lal Nehru Medical College, Allahabad, Uttar Pradesh, India
| | - Reshu Tewari
- Department of Gastroenterology and Hepatology, Moti Lal Nehru Medical College, Allahabad, Uttar Pradesh, India
| | - Ajeet S. Bhadoria
- Department of Epidemiology, Institute of Liver and Biliary Sciences, New Delhi, India
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Jover-Cobos M, Noiret L, Sharifi Y, Jalan R. Ornithine phenylacetate revisited. Metab Brain Dis 2013; 28:327-31. [PMID: 23456516 DOI: 10.1007/s11011-013-9391-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2012] [Accepted: 02/19/2013] [Indexed: 12/12/2022]
Abstract
In patients with liver failure hyperammonemia is associated with the development of hepatic encephalopathy (HE) and immune impairment. Treatment of hyperammonemia is an unmet clinical need. Ornithine phenylacetate (OP) is a novel drug that is targeted at reducing ammonia concentration in patients with liver disease and therefore a potential treatment for HE. This review describes the mechanism of action of OP and its effect on plasma ammonia levels, brain function and inflammation of OP in both acute and chronic liver failure. Ammonia levels could shown to be reduced for up to 24 h in animal models until 120 h in patients with repeated dosing of the drug. Reduction of plasma ammonia levels is due to the stimulation of ammonia removal in the form of glutamine (through glutamine synthetase), the direct excretion of ammonia in the form phenylacetylglutamine and to a normalisation of glutaminase activity in the gut. Administration of OP is associated with a reduction of brain oedema in rats with chronic bile duct ligation and diminution of intracranial hypertension in a pig model of ALF. Studies to date have indicated that it is safe in humans and trials in overt HE are underway to establish OP as a treatment for this major complication of liver disease.
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Affiliation(s)
- Maria Jover-Cobos
- Liver Failure Group, UCL Institute for Liver and Digestive Health, The Royal Free Hospital, University College London, Pond Street, London NW3 2PF, UK.
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Bosoi CR, Rose CF. Brain edema in acute liver failure and chronic liver disease: similarities and differences. Neurochem Int 2013; 62:446-57. [PMID: 23376027 DOI: 10.1016/j.neuint.2013.01.015] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 01/11/2013] [Accepted: 01/16/2013] [Indexed: 12/12/2022]
Abstract
Hepatic encephalopathy (HE) is a complex neuropsychiatric syndrome that typically develops as a result of acute liver failure or chronic liver disease. Brain edema is a common feature associated with HE. In acute liver failure, brain edema contributes to an increase in intracranial pressure, which can fatally lead to brain stem herniation. In chronic liver disease, intracranial hypertension is rarely observed, even though brain edema may be present. This discrepancy in the development of intracranial hypertension in acute liver failure versus chronic liver disease suggests that brain edema plays a different role in relation to the onset of HE. Furthermore, the pathophysiological mechanisms involved in the development of brain edema in acute liver failure and chronic liver disease are dissimilar. This review explores the types of brain edema, the cells, and pathogenic factors involved in its development, while emphasizing the differences in acute liver failure versus chronic liver disease. The implications of brain edema developing as a neuropathological consequence of HE, or as a cause of HE, are also discussed.
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Affiliation(s)
- Cristina R Bosoi
- Neuroscience Research Unit, Hôpital Saint-Luc (CRCHUM), Université de Montréal, Québec, Canada
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Interorgan metabolism of ornithine phenylacetate (OP)—A novel strategy for treatment of hyperammonemia. Biochem Pharmacol 2013; 85:115-23. [DOI: 10.1016/j.bcp.2012.10.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 10/15/2012] [Accepted: 10/16/2012] [Indexed: 11/24/2022]
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Ammonia-lowering strategies for the treatment of hepatic encephalopathy. Clin Pharmacol Ther 2012; 92:321-31. [PMID: 22871998 DOI: 10.1038/clpt.2012.112] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Hyperammonemia leads to neurotoxic levels of brain ammonia and is a major factor involved in the pathogenesis of hepatic encephalopathy (HE). Ammonia-lowering treatments primarily involve two strategies: inhibiting ammonia production and/or increasing ammonia removal. Targeting the gut has been the primary focus for many years, with the goal of inhibiting the generation of ammonia. However, in the context of liver failure, extrahepatic organs containing ammonia metabolic pathways have become new potential ammonia-lowering targets. Skeletal muscle has the capacity to remove ammonia by producing glutamine through the enzyme glutamine synthetase (amidation of glutamate) and, given its large mass, has the potential to be an important ammonia-removing organ. On the other hand, glutamine can be deaminated to glutamate by phosphate-activated glutaminase, thus releasing ammonia (ammonia rebound). Therefore, new treatment strategies are being focused on stimulating the removal of both ammonia and glutamine.
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Wright G, Vairappan B, Stadlbauer V, Mookerjee RP, Davies NA, Jalan R. Reduction in hyperammonaemia by ornithine phenylacetate prevents lipopolysaccharide-induced brain edema and coma in cirrhotic rats. Liver Int 2012; 32:410-9. [PMID: 22151131 DOI: 10.1111/j.1478-3231.2011.02698.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Accepted: 11/08/2011] [Indexed: 12/16/2022]
Abstract
OBJECTIVE In liver failure, inflammation synergistically exacerbates the deleterious cerebral effects of ammonia. The aims were to test whether treatment with the ammonia-lowering agent ornithine phenylacetate (OP) and/or anti-TNF-α (infliximab) prevent the deleterious brain consequences of lipopolysaccharide (LPS) in cirrhotic rats. DESIGN Rats 4 weeks following bile duct-ligation (BDL), sham-operation (sham) and/or 7 days hyperammonemic feed (HD), were randomized to receive LPS (1 mg/kg) or saline, and treatment with either 3 days intraperitoneal injections of OP (0.6 g/kg) and/or infliximab, 10 mg/kg. Animals were sacrificed at coma stages or at 3 h. RESULTS In sham rats, both HD and LPS increased brain water, with an increase in ammonia in the former and brain cytokines in the latter but with no effect on consciousness. BDL + HD rats caused significantly higher plasma ammonia, TNF-α and IL-6 levels compared to sham. LPS significantly worsened coma stage, increased brain water and plasma and brain TNF-α. OP significantly delayed LPS-induced progression to coma stages (P < 0.009), reduced arterial ammonia and brain water (P < 0.001 and P < 0.01 respectively), which was associated with a significant reduction in cytokines. Infliximab significantly reduced plasma and brain cytokines, but not brain water. OP + infliximab attenuated increase in brain water and delayed occurrence of coma, which was not different to OP alone. In BDL rats, OP reduced the expression of brain iNOS and NFκB. CONCLUSION Reduction in ammonia with OP in cirrhotic rats prevents LPS-induced brain edema and delays coma, suggesting that ammonia may prime the brain to the deleterious effect of LPS, possibly through effects on iNOS and NFκB related mechanisms.
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Affiliation(s)
- Gavin Wright
- Liver Failure Group, UCL Institute of Hepatology, Royal Free Hospital, London, UK
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Skowrońska M, Zielińska M, Wójcik-Stanaszek L, Ruszkiewicz J, Milatovic D, Aschner M, Albrecht J. Ammonia increases paracellular permeability of rat brain endothelial cells by a mechanism encompassing oxidative/nitrosative stress and activation of matrix metalloproteinases. J Neurochem 2012; 121:125-34. [PMID: 22260250 DOI: 10.1111/j.1471-4159.2012.07669.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Ammonia is responsible for cerebral edema associated with acute liver failure, but the role of the vasogenic mechanism has been a matter of dispute. Here, we tested the hypothesis that ammonia induces changes in blood-brain barrier (BBB) permeability by a mechanism coupled to oxidative/nitrosative stress (ONS) evoked in the BBB-forming cerebral capillary endothelial cells. Treatment of a rat brain endothelial cell line with ammonia (5 mmol/L, 24 h) caused accumulation of ONS markers: reactive oxygen species, nitric oxide and peroxidation products of phospholipid-bound arachidonic acid, F2-isoprostanes. Concurrently, ammonia increased the activity of extracellular matrix metalloproteinases (MMP-2/MMP-9), increased cell permeability to fluorescein isothiocyanate-dextran (40 kDa), and increased the expression of y+LAT2, a transporter that mediates the uptake to the cells of the nitric oxide precursor, arginine. The increase of cell permeability was ameliorated upon co-treatment with a MMP inhibitor, SB-3CT and with an antioxidant, glutathione diethyl ester, which also reduced F2-isoprostanes. Ammonia-induced ONS was attenuated by cytoprotective agents l-ornithine, phenylbutyrate, and their conjugate l-ornithine phenylbutyrate, an ammonia-trapping drug used to treat hyperammonemia. The results support the concept that ONS and ONS-related activation of MMPs in cerebral capillary endothelial cells contribute to the alterations in BBB permeability and to the vasogenic component of cerebral edema associated with acute liver failure.
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Affiliation(s)
- Marta Skowrońska
- Department of Neurotoxicology, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
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Lee WM. Recent developments in acute liver failure. Best Pract Res Clin Gastroenterol 2012; 26:3-16. [PMID: 22482521 PMCID: PMC3551290 DOI: 10.1016/j.bpg.2012.01.014] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 01/24/2012] [Indexed: 02/08/2023]
Abstract
Acute liver failure is a remarkably rare syndrome, the result of rapid hepatocyte injury occurring over days or a few weeks, and encompassing multiple etiologies, but all with a remarkably similar clinical picture. The clinical features of coagulopathy and encephalopathy characterize this severe and often fatal condition. To date, transplantation has been the only reliable form of rescue for many patients. Recent developments have included a clearer understanding of the different contributing etiologies, how to build a diagnosis and prognosis based on initial laboratory findings, a more aggressive approach to intensive care management and more detailed understanding of the role of transplantation in this setting. This review will provide an overview of standard practices and new research initiatives and findings for this interesting but vexing orphan disease. Particular attention will be paid to practical matters for clinicians to consider in approaching the ALF patient. Few controlled clinical trials have been possible because of the condition's rarity. Critical care of these rare patients is key to their survival and decisions must be made decisively, sometimes with inadequate information. Experience is helpful but experienced clinician managers are even rarer than the disease: few hepatologists or intensivists have in-depth experience with ALF patients.
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Ozanne B, Nelson J, Cousineau J, Lambert M, Phan V, Mitchell G, Alvarez F, Ducruet T, Jouvet P. Threshold for toxicity from hyperammonemia in critically ill children. J Hepatol 2012; 56:123-8. [PMID: 21703182 DOI: 10.1016/j.jhep.2011.03.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Revised: 03/22/2011] [Accepted: 03/24/2011] [Indexed: 01/29/2023]
Abstract
BACKGROUND & AIMS Hyperammonemia results from reduction of hepatocyte function or enzyme of urea cycle deficiency. Hyperammonemia contributes to cerebral edema that may lead to cerebral herniation. The threshold of toxicity of ammonemia is unknown. METHODS We conducted a retrospective observational study in our pediatric intensive care unit. All children who developed hyperammonemia from January 2000 to April 2009 were included. Clinical and laboratory data at admission, specific treatments implemented, and ammonemias the first 7 days after inclusion were collected. The outcome assessed was 28 day mortality. Risk of mortality was estimated by a logistic regression model. RESULTS Ninety patients with liver failure (63.3%) and primary or secondary urea cycle defect (23.3%) were included. Patients with urea cycle defects were more likely to receive ammonia scavengers than patients with liver failure (47.6% versus 3.5%). The 28 day mortality rate was 31.1%. Risk of mortality increased according to the ammonemia within 48 h: odds ratio 1.5, 1.9, 3.3, 2.4 for ammonemia above 100, 150, 200, and 300 μmol/L, respectively. Peak ammonemia ≥200 μmol/L within the first 48 h was an independent risk factor for mortality, with greater risk found in liver failure than in urea cycle defect. CONCLUSIONS Our study identifies a threshold of exposure to ammonia (≥200 μmol/L) above which mortality increases significantly, especially in liver failure. Specific treatments of hyperammonemia are rarely used in liver failure when compared with urea cycle defect even though use of ammonia scavengers may help to decrease ammonemia.
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Affiliation(s)
- Bruno Ozanne
- CHU Sainte-Justine, Soins Intensifs, 3175 Chemin de la Côte Sainte-Catherine, Montréal (QC), Canada H3T 1C5
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