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Shawcross DL, Thabut D, Amodio P. Ammonia - an enduring foe - What evaluating whole body ammonia metabolism can teach us about cirrhosis and therapies treating hepatic encephalopathy. J Hepatol 2023:S0168-8278(23)00327-6. [PMID: 37178732 DOI: 10.1016/j.jhep.2023.04.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 04/27/2023] [Indexed: 05/15/2023]
Affiliation(s)
- Debbie L Shawcross
- Institute of Liver Studies, School of Immunology and Microbial Sciences, Faculty of Life Sciences and Medicine, King's College London, 125 Coldharbour Lane, London SE5 9NU, UK; Institute of Liver Studies, King's College Hospital NHS Foundation Trust, Denmark Hill, London, SE5 9RS, UK.
| | - Dominique Thabut
- Brain Liver Salpêtrière Study Group, Sorbonne Université, INSERM UMR_S 938, Centre de Recherche Saint-Antoine & Institute of Cardiometabolism and Nutrition (ICAN), Paris 75013, France; AP-HP; Sorbonne Université, Liver Intensive Care Unit, Hepatogastroenterology Department, Pitié-Salpêtrière Hospital, 47-83 Boulevard de l'Hôpital, Paris 75013, France; Sorbonne Université, Paris F-75005, France
| | - Piero Amodio
- Department of Medicine, University of Padova, Italy
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2
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Mpabanzi L, Wainwright J, Boonen B, van Eijk H, Dhar D, Karssemeijer E, Dejong CHC, Jalan R, Schwartz JM, Olde Damink SWM, Soons Z. Fluxomics reveals cellular and molecular basis of increased renal ammoniagenesis. NPJ Syst Biol Appl 2022; 8:49. [PMID: 36539425 PMCID: PMC9768161 DOI: 10.1038/s41540-022-00257-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 11/07/2022] [Indexed: 12/24/2022] Open
Abstract
The kidney plays a critical role in excreting ammonia during metabolic acidosis and liver failure. The mechanisms behind this process have been poorly explored. The present study combines results of in vivo experiments of increased total ammoniagenesis with systems biology modeling, in which eight rats were fed an amino acid-rich diet (HD group) and eight a normal chow diet (AL group). We developed a method based on elementary mode analysis to study changes in amino acid flux occurring across the kidney in increased ammoniagenesis. Elementary modes represent minimal feasible metabolic paths in steady state. The model was used to predict amino acid fluxes in healthy and pre-hyperammonemic conditions, which were compared to experimental fluxes in rats. First, we found that total renal ammoniagenesis increased from 264 ± 68 to 612 ± 87 nmol (100 g body weight)-1 min-1 in the HD group (P = 0.021) and a concomitated upregulation of NKCC2 ammonia and other transporters in the kidney. In the kidney metabolic model, the best predictions were obtained with ammonia transport as an objective. Other objectives resulting in a fair correlation with the measured fluxes (correlation coefficient >0.5) were growth, protein uptake, urea excretion, and lysine and phenylalanine transport. These predictions were improved when specific gene expression data were considered in HD conditions, suggesting a role for the mitochondrial glycine pathway. Further studies are needed to determine if regulation through the mitochondrial glycine pathway and ammonia transporters can be modulated and how to use the kidney as a therapeutic target in hyperammonemia.
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Affiliation(s)
- Liliane Mpabanzi
- grid.5012.60000 0001 0481 6099Department of Surgery, Maastricht University Medical Centre, and NUTRIM School of Nutrition, Toxicology and Metabolism, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands ,grid.83440.3b0000000121901201Hepato-Pancreato-Biliary and Liver Transplant Surgery, Royal Free Hospital, University College London, Pond Street, London, NW3 2QG UK ,grid.83440.3b0000000121901201Liver Failure Group, UCL Hepatology, Royal Free Hospital, University College London, Pond Street, London, NW3 2QG UK
| | - Jessica Wainwright
- grid.5379.80000000121662407School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT UK
| | - Bas Boonen
- grid.5012.60000 0001 0481 6099Department of Surgery, Maastricht University Medical Centre, and NUTRIM School of Nutrition, Toxicology and Metabolism, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands
| | - Hans van Eijk
- grid.5012.60000 0001 0481 6099Department of Surgery, Maastricht University Medical Centre, and NUTRIM School of Nutrition, Toxicology and Metabolism, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands
| | - Dipok Dhar
- grid.83440.3b0000000121901201Hepato-Pancreato-Biliary and Liver Transplant Surgery, Royal Free Hospital, University College London, Pond Street, London, NW3 2QG UK
| | - Esther Karssemeijer
- grid.5012.60000 0001 0481 6099Department of Surgery, Maastricht University Medical Centre, and NUTRIM School of Nutrition, Toxicology and Metabolism, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands
| | - Cees H. C. Dejong
- grid.5012.60000 0001 0481 6099Department of Surgery, Maastricht University Medical Centre, and NUTRIM School of Nutrition, Toxicology and Metabolism, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands ,grid.412301.50000 0000 8653 1507Department of General, Visceral and Transplantation Surgery, University Hospital RWTH Aachen, Aachen, Germany
| | - Rajiv Jalan
- grid.83440.3b0000000121901201Liver Failure Group, UCL Hepatology, Royal Free Hospital, University College London, Pond Street, London, NW3 2QG UK
| | - Jean-Marc Schwartz
- grid.5379.80000000121662407School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT UK
| | - Steven W. M. Olde Damink
- grid.5012.60000 0001 0481 6099Department of Surgery, Maastricht University Medical Centre, and NUTRIM School of Nutrition, Toxicology and Metabolism, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands ,grid.83440.3b0000000121901201Hepato-Pancreato-Biliary and Liver Transplant Surgery, Royal Free Hospital, University College London, Pond Street, London, NW3 2QG UK ,grid.412301.50000 0000 8653 1507Department of General, Visceral and Transplantation Surgery, University Hospital RWTH Aachen, Aachen, Germany
| | - Zita Soons
- grid.5012.60000 0001 0481 6099Department of Surgery, Maastricht University Medical Centre, and NUTRIM School of Nutrition, Toxicology and Metabolism, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands ,grid.412301.50000 0000 8653 1507Research Center for Computational Biomedicine, University Hospital RWTH Aachen, Aachen, Germany
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Wu T, Zheng X, Yang M, Zhao A, Xiang H, Chen T, Jia W, Ji G. Serum Amino Acid Profiles Predict the Development of Hepatocellular Carcinoma in Patients with Chronic HBV Infection. ACS OMEGA 2022; 7:15795-15808. [PMID: 35571782 PMCID: PMC9097210 DOI: 10.1021/acsomega.2c00885] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Accepted: 04/12/2022] [Indexed: 05/04/2023]
Abstract
Background: The study aimed to find out the alterations in serum amino acid (AA) profiles and to detect their relationship with carcinoma formation. Methods: Targeted metabolomics based on ultraperformance liquid chromatography triple quadrupole mass spectrometry to quantitatively analyze serum AA levels in 136 hepatitis B (CHB) patients and 93 hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) patients. Results: It was shown that decreased serum levels of leucine, lysine, threonine, tryptophan, valine, serotonin, and taurine were observed in more HCC patients than CHB patients, but the serum phenylalanine level was increased. Serum valine and serotonin were lower in Class C than Class A and Class B in HCC patients. Accompanied with the higher score of Model for End-Stage Liver Disease, serum phenylalanine was increased not only in CHB patients but also in HCC patients. The serum level of phenylalanine increased in the decompensated stage more than in the compensated stage, while serum leucine and serotonin significantly decreased. Serum serotonin still had significant differences between CHB and HCC both in the HBV desoxyribonucleic acid (HBV-DNA) negative group and in the HBV-DNA positive group. Furthermore, it was shown that the tryptophan ratio, branched-chain amino acids (BCAA)/aromatic amino acids ratio, BCAAs/tyrosine ratio, Fischer's ratio, and serotonin-to-tryptophan ratio significantly decreased, while the tyrosine ratio and the kynurenine-to-tryptophan ratio increased in HCC patients more than those in CHB. Conclusions: A distinct metabolite signature of some specific serum amino acids was found between CHB and HCC patients, which may help predict the development of HCC at an early stage.
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Affiliation(s)
- Tao Wu
- Institute
of Digestive Disease, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200032, China
- Institute
of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Xiaojiao Zheng
- Shanghai
Key Laboratory of Diabetes Mellitus and Center for Translational Medicine, Shanghai Jiao Tong University Affiliated Sixth People’s
Hospital, Shanghai 200233, China
| | - Ming Yang
- Institute
of Digestive Disease, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200032, China
| | - Aihua Zhao
- Shanghai
Key Laboratory of Diabetes Mellitus and Center for Translational Medicine, Shanghai Jiao Tong University Affiliated Sixth People’s
Hospital, Shanghai 200233, China
| | - Hongjiao Xiang
- Institute
of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Tianlu Chen
- Shanghai
Key Laboratory of Diabetes Mellitus and Center for Translational Medicine, Shanghai Jiao Tong University Affiliated Sixth People’s
Hospital, Shanghai 200233, China
| | - Wei Jia
- Shanghai
Key Laboratory of Diabetes Mellitus and Center for Translational Medicine, Shanghai Jiao Tong University Affiliated Sixth People’s
Hospital, Shanghai 200233, China
- School
of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong HKSAR, Hong Kong, China
| | - Guang Ji
- Institute
of Digestive Disease, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200032, China
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Kim JH, Jeon H, Lee SS, Heo IR, Choi JW, Kim HJ, Cha RR, Lee JM, Kim HJ. Impact of non-hepatic hyperammonemia on mortality in intensive care unit patients: a retrospective cohort study. Korean J Intern Med 2021; 36:1347-1355. [PMID: 34256430 PMCID: PMC8588975 DOI: 10.3904/kjim.2021.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 04/26/2021] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND/AIMS The effect of hyperammonemia on the mortality in patients with liver cirrhosis is well documented. However, little is known about the impact of hyperammonemia on mortality among intensive care unit patients without hepatic disease. We aimed to investigate factors associated with non-hepatic hyperammonemia among intensive care unit patients and to evaluate the factors related to the 7- and 90-day mortality. METHODS Between February 2016 and February 2020, 948 patients without hepatic disease who had 972 episodes of admission to the intensive care unit were retrospectively enrolled and classified as hyperammonemia grades 0 (≤ 80 µg/dL; 585 [60.2%]), 1 (≤ 160 µg/dL; 291 [29.9%]), 2 (≤ 240 µg/dL; 55 [5.7%]), and 3 (> 240 µg/dL; 41 [4.2%]). Factors associated with hyperammonemia and the 7- and 90-day mortality were evaluated by multivariate logistic regression analysis and Cox regression analysis, respectively. Kaplan-Meier survival curves for the 7- and 90-day mortality were constructed. RESULTS The independent risk factors for hyperammonemia were male sex (odds ratio, 1.517), age (0.984/year), acute brain failure (2.467), acute kidney injury (1.437), prothrombin time-international normalized ratio (2.272/unit), and albumin (0.694/g/dL). The 90-day mortality rate in the entire cohort was 24.3% and gradually increased with increasing hyperammonemia grade at admission (17.9%, 28.2%, 43.6%, and 61.0% in patients with grades 0, 1, 2, and 3, respectively). Additionally, non-hepatic hyperammonemia was an independent predictor of the 90- day mortality in intensive care unit patients. CONCLUSION Non-hepatic hyperammonemia is common (39.8%) and associated with the 90-day mortality among intensive care unit patients.
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Affiliation(s)
- Jae Heon Kim
- Department of Internal Medicine, Gyeongsang National University Hospital, Jinju,
Korea
- Department of Internal Medicine, Gyeongsang National University Changwon Hospital, Changwon,
Korea
| | - Hankyu Jeon
- Department of Internal Medicine, Gyeongsang National University Hospital, Jinju,
Korea
- Department of Internal Medicine, Gyeongsang National University Changwon Hospital, Changwon,
Korea
| | - Sang Soo Lee
- Department of Internal Medicine, Gyeongsang National University Hospital, Jinju,
Korea
- Department of Internal Medicine, Gyeongsang National University Changwon Hospital, Changwon,
Korea
- Institute of Health Sciences, Gyeongsang National University, Jinju,
Korea
| | - I Re Heo
- Department of Internal Medicine, Gyeongsang National University Hospital, Jinju,
Korea
- Department of Internal Medicine, Gyeongsang National University Changwon Hospital, Changwon,
Korea
| | - Jung Woo Choi
- Department of Internal Medicine, Gyeongsang National University Hospital, Jinju,
Korea
| | - Hee Jin Kim
- Department of Internal Medicine, Gyeongsang National University Hospital, Jinju,
Korea
- Department of Internal Medicine, Gyeongsang National University Changwon Hospital, Changwon,
Korea
- Institute of Health Sciences, Gyeongsang National University, Jinju,
Korea
| | - Ra Ri Cha
- Department of Internal Medicine, Gyeongsang National University Hospital, Jinju,
Korea
- Department of Internal Medicine, Gyeongsang National University Changwon Hospital, Changwon,
Korea
- Institute of Health Sciences, Gyeongsang National University, Jinju,
Korea
| | - Jae Min Lee
- Department of Internal Medicine, Gyeongsang National University Hospital, Jinju,
Korea
- Department of Internal Medicine, Gyeongsang National University Changwon Hospital, Changwon,
Korea
- Institute of Health Sciences, Gyeongsang National University, Jinju,
Korea
| | - Hyun Jin Kim
- Department of Internal Medicine, Gyeongsang National University Hospital, Jinju,
Korea
- Department of Internal Medicine, Gyeongsang National University Changwon Hospital, Changwon,
Korea
- Institute of Health Sciences, Gyeongsang National University, Jinju,
Korea
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5
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Fukuda M, Nabeta M, Muta T, Cho T, Shimamatsu Y, Shimotsuura Y, Fukami K, Takasu O. Disturbance of consciousness due to hyperammonemia and lactic acidosis during mFOLFOX6 regimen: Case report. Medicine (Baltimore) 2020; 99:e21743. [PMID: 32872062 PMCID: PMC7437776 DOI: 10.1097/md.0000000000021743] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
INTRODUCTION FOLFOX therapy is the main chemotherapy regimen for colorectal cancer. Peripheral neuropathy, hematotoxicity, and digestive symptoms are known to be the most frequent adverse events. Hyperammonemia and lactic acidosis rarely occur simultaneously during treatment with FOLFOX therapy; the number of case reports is limited worldwide. We report a case of disturbance of consciousness, considered to be caused by hyperammonemia and lactic acidosis that occurred during treatment with mFOLFOX6 therapy that was administered as postoperative adjuvant treatment for rectal cancer. PATIENT CONCERNS This case was of a 71-year-old man who had been receiving oral treatment for chronic kidney disease and diabetes mellitus. Laparoscopic low anterior resection and artificial anal construction surgery were performed for stage III rectal cancer. As adjuvant postoperative therapy, mFOLFOX6 therapy was started but was followed by a disturbance of consciousness. DIAGNOSES Results of the blood tests revealed notable hyperammonemia (ammonia level, 1,163 μg/dl) and lactic acidosis (pH 7.207; lactate, 17.56 mmol/L); however, imaging diagnosis did not reveal intracranial lesions that could cause disturbance of consciousness. INTERVENTIONS For hyperammonemia, branched-chain amino acid agents and Ringers solution supplementation were administered. For acidosis, 7% sodium hydrogen carbonate was administered as treatment. OUTCOMES The disturbance of consciousness improved within 12 hours of initiating the treatment, and the patient was discharged with no sequelae on 7th day after hospitalization. CONCLUSION In patients with chronic kidney disease, FOLFOX regimen may confer risks of hyperammonemia and lactic acidosis.
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Affiliation(s)
- Masafumi Fukuda
- Advanced Emergency and Critical Care Center, Kurume University Hospital
| | | | - Takanori Muta
- Department of Emergency and Acute Intensive Care Medicine
| | | | | | | | - Kei Fukami
- Division of Nephrology, Department of Medicine, Kurume University School of Medicine, Kurume, Fukuoka, Japan
| | - Osamu Takasu
- Department of Emergency and Acute Intensive Care Medicine
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Lee YS, Choi YJ, Park KH, Park BS, Son JM, Park JY, Ri HS, Ryu JH. Liver Transplant Patients with High Levels of Preoperative Serum Ammonia Are at Increased Risk for Postoperative Acute Kidney Injury: A Retrospective Study. J Clin Med 2020; 9:jcm9061629. [PMID: 32481585 PMCID: PMC7356740 DOI: 10.3390/jcm9061629] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/18/2020] [Accepted: 05/18/2020] [Indexed: 01/09/2023] Open
Abstract
Acute kidney injury (AKI) is one of the most frequent postoperative complications after liver transplantation (LT). Increased serum ammonia levels due to the liver disease itself may affect postoperative renal function. This study aimed to compare the incidence of postoperative AKI according to preoperative serum ammonia levels in patients after LT. Medical records from 436 patients who underwent LT from January 2010 to February 2020 in a single university hospital were retrospectively reviewed. The patients were then categorized according to changes in plasma creatinine concentrations within 48 h of LT using the Acute Kidney Injury Network criteria. A preoperative serum ammonia level above 45 mg/dL was associated with postoperative AKI (p < 0.0001). Even in patients with a normal preoperative creatinine level, when the ammonia level was greater than 45 μg/dL, the incidence of postoperative AKI was significantly higher (p < 0.0001); the AKI stage was also higher in this group than in the group with preoperative ammonia levels less than or equal to 45 μg/dL (p < 0.0001). Based on the results of our research, an elevation in preoperative serum ammonia levels above 45 μg/dL is related to postoperative AKI after LT.
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Affiliation(s)
- Yoon Sook Lee
- Department of Anaesthesiology and Pain Medicine, Ansan Hospital, Korea University, College of Medicine, Ansan 15355, Korea; (Y.S.L.); (B.S.P.)
| | - Yoon Ji Choi
- Department of Anaesthesiology and Pain Medicine, Ansan Hospital, Korea University, College of Medicine, Ansan 15355, Korea; (Y.S.L.); (B.S.P.)
- Correspondence: ; Tel.: +82-10-7900-7825
| | - Kyu Hee Park
- Department of Pediatrics, Korea University Hospital, Ansan 15355, Korea;
| | - Byeong Seon Park
- Department of Anaesthesiology and Pain Medicine, Ansan Hospital, Korea University, College of Medicine, Ansan 15355, Korea; (Y.S.L.); (B.S.P.)
| | - Jung-Min Son
- Department of Biostatistics, Clinical Trial Center, Biomedical Research Institute, Pusan National University Hospital, Pusan 49241, Korea;
| | - Ju Yeon Park
- Department of Anesthesiology and Pain Medicine, Daedong Hospital, Busan 47737, Korea;
| | - Hyun-Su Ri
- Department of Anaesthesia and Pain Medicine, Pusan National University Yangsan Hospital, Yangsan 50612, Korea;
| | - Je Ho Ryu
- Division of Hepato-Biliary-Pancreatic Surgery and Transplantation, Department of Surgery, Pusan National University Yangsan Hospital, Pusan National University School of Medicine, Yangsan 50612, Korea;
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A serendipitous voyage in the field of nutrition and metabolism in health and disease: a translational adventure. Eur J Clin Nutr 2020; 74:1375-1388. [PMID: 32060384 DOI: 10.1038/s41430-020-0584-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 01/29/2020] [Accepted: 01/31/2020] [Indexed: 11/08/2022]
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Levitt MD, Levitt DG. Use Of Quantitative Modelling To Elucidate The Roles Of The Liver, Gut, Kidney, And Muscle In Ammonia Homeostasis And How Lactulose And Rifaximin Alter This Homeostasis. Int J Gen Med 2019; 12:367-380. [PMID: 31686894 PMCID: PMC6798813 DOI: 10.2147/ijgm.s218405] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 09/24/2019] [Indexed: 12/18/2022] Open
Abstract
Humans must eliminate approximately 1M of ammonia per day while maintaining the blood concentration of this potent neurotoxin at a concentration of only about 30 µM. The mechanisms producing such effective ammonia homeostasis are poorly understood by clinicians due to the multiple organs (liver, gut, kidney and muscle) involved in ammonia homeostasis. Based on literature values we present a novel, simplified description of normal and disordered ammonia and the potential mechanisms whereby the drugs used to treat hepatic encephalopathy, lactulose and rifaximin, lower the blood ammonia concentration. Concepts discussed include the following: 1) only about 44 mmol of ammonia/day (4.4% of total production) reaches the peripheral circulation due to the efficient linkage of amino deamination and the urea cycle in hepatic mitochondria; 2) the gut and kidney contribute roughly equally to delivery of this 44 mmol/day to systemic blood; 3) the bulk of gut ammonia production seemingly originates in the small bowel from bacterial deamination of urea by bacteria and mucosal deamination of circulating and ingested glutamine; 4) the apparent production of ammonia in the small bowel markedly exceeds that quantity that enters the portal blood, indicating that ammonia disposal mechanisms in the small bowel play a major role in ammonia homeostasis. With regard to the hyperammonemia of chronic liver disease: 1) shunting of portal blood around the liver, by itself, can account for commonly observed ammonia elevations; 2) severe portal hypertension causes an increased release of ammonia by the kidney; 3) high blood ammonia is associated with an unexplained massive increase in the muscle uptake of ammonia that could play an important role in limiting hyperammonemia; and 4) a major action of lactulose administration may be the enhancement of ammonia uptake by small bowel bacteria, while the mechanism of action of rifaximin is unclear.
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Affiliation(s)
- Michael D Levitt
- Research Service, Veterans Affairs Medical Center, Minneapolis, MN 55417, USA
| | - David G Levitt
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN 55455, USA
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Intravenous and Oral Hyperammonemia Management. CURRENT EMERGENCY AND HOSPITAL MEDICINE REPORTS 2018. [DOI: 10.1007/s40138-018-0174-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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10
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Levitt DG, Levitt MD. A model of blood-ammonia homeostasis based on a quantitative analysis of nitrogen metabolism in the multiple organs involved in the production, catabolism, and excretion of ammonia in humans. Clin Exp Gastroenterol 2018; 11:193-215. [PMID: 29872332 PMCID: PMC5973424 DOI: 10.2147/ceg.s160921] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Increased blood ammonia (NH3) is an important causative factor in hepatic encephalopathy, and clinical treatment of hepatic encephalopathy is focused on lowering NH3. Ammonia is a central element in intraorgan nitrogen (N) transport, and modeling the factors that determine blood-NH3 concentration is complicated by the need to account for a variety of reactions carried out in multiple organs. This review presents a detailed quantitative analysis of the major factors determining blood-NH3 homeostasis – the N metabolism of urea, NH3, and amino acids by the liver, gastrointestinal system, muscle, kidney, and brain – with the ultimate goal of creating a model that allows for prediction of blood-NH3 concentration. Although enormous amounts of NH3 are produced during normal liver amino-acid metabolism, this NH3 is completely captured by the urea cycle and does not contribute to blood NH3. While some systemic NH3 derives from renal and muscle metabolism, the primary site of blood-NH3 production is the gastrointestinal tract, as evidenced by portal vein-NH3 concentrations that are about three times that of systemic blood. Three mechanisms, in order of quantitative importance, release NH3 in the gut: 1) hydrolysis of urea by bacterial urease, 2) bacterial protein deamination, and 3) intestinal mucosal glutamine metabolism. Although the colon is conventionally assumed to be the major site of gut-NH3 production, evidence is reviewed that indicates that the stomach (via Helicobacter pylori metabolism) and small intestine and may be of greater importance. In healthy subjects, most of this gut NH3 is removed by the liver before reaching the systemic circulation. Using a quantitative model, loss of this “first-pass metabolism” due to portal collateral circulation can account for the hyperammonemia observed in chronic liver disease, and there is usually no need to implicate hepatocyte malfunction. In contrast, in acute hepatic necrosis, hyperammonemia results from damaged hepatocytes. Although muscle-NH3 uptake is normally negligible, it can become important in severe hyperammonemia. The NH3-lowering actions of intestinal antibiotics (rifaximin) and lactulose are discussed in detail, with particular emphasis on the seeming lack of importance of the frequently emphasized acidifying action of lactulose in the colon.
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Affiliation(s)
- David G Levitt
- Department of Integrative Biology and Physiology, University of Minnesota
| | - Michael D Levitt
- Research Service, Veterans Affairs Medical Center, Minneapolis, MN, USA
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11
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Cruz NF, Dienel GA, Patrick PA, Cooper AJL. Organ Distribution of 13N Following Intravenous Injection of [ 13N]Ammonia into Portacaval-Shunted Rats. Neurochem Res 2016; 42:1683-1696. [PMID: 27822667 DOI: 10.1007/s11064-016-2096-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 10/27/2016] [Accepted: 10/31/2016] [Indexed: 12/18/2022]
Abstract
Ammonia is neurotoxic, and chronic hyperammonemia is thought to be a major contributing factor to hepatic encephalopathy in patients with liver disease. Portacaval shunting of rats is used as an animal model to study the detrimental metabolic effects of elevated ammonia levels on body tissues, particularly brain and testes that are deleteriously targeted by high blood ammonia. In normal adult rats, the initial uptake of label (expressed as relative concentration) in these organs was relatively low following a bolus intravenous injection of [13N]ammonia compared with lungs, kidneys, liver, and some other organs. The objective of the present study was to determine the distribution of label following intravenous administration of [13N]ammonia among 14 organs in portacaval-shunted rats at 12 weeks after shunt construction. At an early time point (12 s) following administration of [13N]ammonia the relative concentration of label was highest in lung with lower, but still appreciable relative concentrations in kidney and heart. Clearance of 13N from blood and kidney tended to be slower in portacaval-shunted rats versus normal rats during the 2-10 min interval after the injection. At later times post injection, brain and testes tended to have higher-than-normal 13N levels, whereas many other tissues had similar levels in both groups. Thus, reduced removal of ammonia from circulating blood by the liver diverts more ammonia to extrahepatic tissues, including brain and testes, and alters the nitrogen homeostasis in these tissues. These results emphasize the importance of treatment paradigms designed to reduce blood ammonia levels in patients with liver disease.
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Affiliation(s)
- Nancy F Cruz
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Gerald A Dienel
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
- Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, NM, USA
| | | | - Arthur J L Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, 15 Dana Road, Valhalla, NY, 10595, USA.
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12
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Patwardhan VR, Jiang ZG, Risech-Neiman Y, Piatkowski G, Afdhal NH, Mukamal K, Curry MP, Tapper EB. Serum Ammonia is Associated With Transplant-free Survival in Hospitalized Patients With Acutely Decompensated Cirrhosis [corrected]. J Clin Gastroenterol 2016; 50:345-50. [PMID: 26565968 DOI: 10.1097/mcg.0000000000000443] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND As ammonia metabolism is a complex multiorgan process, we sought to determine whether serum ammonia concentrations were associated with transplant-free survival in patients with acutely decompensated cirrhosis and acute-on-chronic liver failure (ACLF). METHODS We studied 494 consecutive patients hospitalized with cirrhosis between April 2007 and September 2012 with venous ammonia measured on hospital admission. The primary outcome was transplant-free survival. RESULTS Overall, rates of death or transplant within 30 and 90 days were 23.1% (n=114) and 37.7% (n=186), respectively. Forty-six patients (9.2%) underwent liver transplantation within 90 days. In a multivariate Cox proportional hazards model, ammonia concentration was independently associated with death or transplantation within 30 and 90 days after adjusting for model for end-stage liver disease, sodium, white blood cells, and number of ACLF organ failures; every doubling of ammonia was associated with respective hazard ratios of 1.22 (95% confidence interval, 1.03-1.38) and 1.21 (95% confidence interval, 1.04-1.44) for 90- and 30-day transplant or mortality. Notably, after adjusting for ammonia, organ failures were not predictive of outcomes. In a Kaplan-Meier analysis, patients with admission ammonia concentrations >60 μmol/L had significantly lower 90-day transplant-free survival (P=0.0004). Patients with admission ammonia concentrations >60 μmol/L had higher 90- and 30-day risk of death or transplantation (45.2% vs. 31.2%, P=0.001; and 31.6% vs. 15.7%, P<0.0001, respectively). CONCLUSION For patients with acutely decompensated cirrhosis, an elevated serum ammonia concentration on admission is associated with reduced 90-day transplant-free survival after adjusting for established predictors.
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Affiliation(s)
- Vilas R Patwardhan
- *Division of Gastroenterology†Department of Medicine‡Decision Support, Beth Israel Deaconess Medical Center, Boston, MA
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Tapper EB, Jiang ZG, Patwardhan VR. Refining the ammonia hypothesis: a physiology-driven approach to the treatment of hepatic encephalopathy. Mayo Clin Proc 2015; 90:646-58. [PMID: 25865476 DOI: 10.1016/j.mayocp.2015.03.003] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Revised: 02/27/2015] [Accepted: 03/03/2015] [Indexed: 12/12/2022]
Abstract
Hepatic encephalopathy (HE) is one of the most important complications of cirrhosis and portal hypertension. Although the etiology is incompletely understood, it has been linked to ammonia directly and indirectly. Our goal is to review for the clinician the mechanisms behind hyperammonemia and the pathogenesis of HE to explain the rationale for its therapy. We reviewed articles collected through a search of MEDLINE/PubMed, Cochrane Database of Systematic Reviews, and Google Scholar between October 1, 1948, and December 8, 2014, and by a manual search of citations within retrieved articles. Search terms included hepatic encephalopathy, ammonia hypothesis, brain and ammonia, liver failure and ammonia, acute-on-chronic liver failure and ammonia, cirrhosis and ammonia, portosytemic shunt, ammonia and lactulose, rifaximin, zinc, and nutrition. Ammonia homeostatsis is a multiorgan process involving the liver, brain, kidneys, and muscle as well as the gastrointestinal tract. Indeed, hyperammonemia may be the first clue to poor functional reserves, malnutrition, and impending multiorgan dysfunction. Furthermore, the neuropathology of ammonia is critically linked to states of systemic inflammation and endotoxemia. Given the complex interplay among ammonia, inflammation, and other factors, ammonia levels have questionable utility in the staging of HE. The use of nonabsorbable disaccharides, antibiotics, and probiotics reduces gut ammoniagenesis and, in the case of antibiotics and probiotics, systemic inflammation. Nutritional support preserves urea cycle function and prevents wasting of skeletal muscle, a significant site of ammonia metabolism. Correction of hypokalemia, hypovolemia, and acidosis further assists in the reduction of ammonia production in the kidney. Finally, early and aggressive treatment of infection, avoidance of sedatives, and modification of portosystemic shunts are also helpful in reducing the neurocognitive effects of hyperammonemia. Refining the ammonia hypothesis to account for these other factors instructs a solid foundation for the effective treatment and prevention of hepatic encephalopathy.
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Affiliation(s)
- Elliot B Tapper
- Division of Gastroenterology, Beth Israel Deaconess Medical Center, Boston, MA.
| | - Z Gordon Jiang
- Division of Gastroenterology, Beth Israel Deaconess Medical Center, Boston, MA
| | - Vilas R Patwardhan
- Division of Gastroenterology, Beth Israel Deaconess Medical Center, Boston, MA
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Noiret L, Baigent S, Jalan R. Arterial ammonia levels in cirrhosis are determined by systemic and hepatic hemodynamics, and by organ function: a quantitative modelling study. Liver Int 2014; 34:e45-55. [PMID: 24134128 DOI: 10.1111/liv.12361] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2013] [Accepted: 10/13/2013] [Indexed: 12/13/2022]
Abstract
BACKGROUND & AIMS Hyperammonaemia is a common complication of chronic liver failure. Two main factors are thought to underlie this complication: a loss of hepatic detoxification function and the development of portosystemic shunting. However, few studies have tried to quantify the importance of portosystemic shunting. Here, we used a theoretical approach to test the hypothesis that the development of portosystemic shunting is sufficient to cause hyperammonaemia in cirrhosis. METHODS Two mathematical models are developed. The first one describes the main vascular resistances of the circulation and is used to provide scenarios for the distributions of organ blood flow in cirrhosis, which are necessary to run the second model. The second model predicts arterial ammonia levels resulting from ammonia metabolism in gut, liver, kidney, muscle and brain, and the distribution of organ blood flow. RESULTS The fraction of gastrointestinal blood flow shunted through collaterals was estimated to be 41% in mild cirrhosis, 69% in moderate and 85% in severe cases. In the second model, the redistribution of organ blood flow associated with severe cirrhosis was sufficient to cause hyperammonaemia, even when the hepatic detoxification function and the ammonia production were set to normal. CONCLUSIONS The model indicates that the development of portosystemic shunting in cirrhosis is sufficient to cause hyperammonaemia. Interventions that reduce the fraction of shunting may be future targets of therapy to control severity of hyperammonaemia.
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Anwar S, Gupta D, Ashraf MA, Khalid SA, Rizvi SM, Miller BW, Brennan DC. Symptomatic hyperammonemia after lung transplantation: lessons learnt. Hemodial Int 2013; 18:185-91. [PMID: 23998793 DOI: 10.1111/hdi.12088] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Hyperammonemia, post-orthotopic lung transplantation, is a rare but mostly fatal complication. Various therapies, including those to decrease ammonia generation, increase nitrogen excretion, and several dialytic methods for removing ammonia have been tried. We describe three lung transplant recipients who developed acute hyperammonemia early after transplantation. Two of the three patients survived after a multidisciplinary approach including discontinuation of drugs, which impair urea cycle, aggressive ammonia reduction with prolonged daily intermittent hemodialysis (HD), and overnight slow low-efficiency dialysis in conjunction with early weaning of steroids and other therapeutic measures. Our experience suggests that early initiation of dialysis, high dialysis dose, increased frequency, and HD preferably to less efficient modalities increases survival in these patients.
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Affiliation(s)
- Siddiq Anwar
- Department of Medicine, Washington University School of Medicine, St Louis, Missouri, USA
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Kalaitzakis E, Josefsson A, Castedal M, Henfridsson P, Bengtsson M, Andersson B, Björnsson E. Hepatic encephalopathy is related to anemia and fat-free mass depletion in liver transplant candidates with cirrhosis. Scand J Gastroenterol 2013; 48:577-84. [PMID: 23452072 DOI: 10.3109/00365521.2013.777468] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Although muscle wasting may lead to decreased ammonia detoxification in cirrhosis, the potential role of lean mass depletion in hepatic encephalopathy (HE) has not been explored. Anemia, hormonal abnormalities, and psychological distress may contribute to cognitive dysfunction, but data on their potential relation to HE are limited. METHODS Data on 108 cirrhotic liver transplant candidates enrolled in a prospective study on fatigue were retrospectively analyzed. HE was assessed clinically and with the number connection tests (NCT) A and B. Psychosocial distress was assessed with a validated questionnaire. Fasting serum glucose, insulin, ammonia, and the glomerular filtration rate (GFR) were measured. Fat and fat-free mass was evaluated with dual-energy X-ray absorptiometry. Serum cortisol, testosterone, dehydroepiandrosterone, thyroid function tests, interleukin-6, and tumor necrosis factor-α (TNF-α) were measured in a subgroup of 80 patients. RESULTS A total of 28% of patients had (overt or minimal) HE. Anemia was present in 59%, diabetes in 29%, renal impairment in 16%, and fat-free mass depletion in 14%. In multivariate analysis, fat-free mass depletion was an independent predictor of HE and NCT-A; renal impairment of NCT-A and -B; and anemia of NCT-B (p < 0.05 for all). HE was also independently related to international normalized ratio and TNF-α (p < 0.05 for both), but not to other hormonal abnormalities or psychological distress. Plasma ammonia was independently associated to anemia (beta = 15.24, p = 0.049), fasting insulin (beta = 0.26, p < 0.05), and GFR (beta = -0.43, p = 0.003). CONCLUSIONS Anemia and fat-free mass depletion are predictors of HE in cirrhotic liver transplant candidates along with liver failure, renal impairment, and systemic inflammation.
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Affiliation(s)
- Evangelos Kalaitzakis
- Institute of Internal Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
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Mpabanzi L, Deutz N, Hayes PC, Dejong CHC, Olde Damink SWM, Jalan R. Overnight glucose infusion suppresses renal ammoniagenesis and reduces hyperammonaemia induced by a simulated bleed in cirrhotic patients. Aliment Pharmacol Ther 2012; 35:921-8. [PMID: 22360430 DOI: 10.1111/j.1365-2036.2012.05044.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 12/23/2011] [Accepted: 02/02/2012] [Indexed: 12/18/2022]
Abstract
BACKGROUND A simulated upper gastrointestinal (UGI) bleed in cirrhotic patients has been shown to induce hyperammonaemia. The kidney was the site of this exaggerated ammoniagenesis with alanine as substrate. Administration of alanine to decompensated cirrhotic patients did not change hepatic gluconeogenesis, but resulted in increased ammoniagenesis. We hypothesise that reduced hepatic glycogen stores result in hyperglucagonaemia which may drive increased renal gluconeogenesis and therefore alanine uptake and renal ammoniagenesis. AIM To determine whether an overnight glucose infusion lowers renal ammoniagenesis by reducing hyperglucagonaemia and renal ammoniagenesis. METHODS Patients with decompensated cirrhosis were studied in a cross-over design. An UGI bleed was simulated via intragastric administration of an amino acids mixture mimicking the haemoglobin molecule after a 12-h overnight fast (F-group) or after a 12-h treatment with 20% glucose solution (G-group). RESULTS Before the simulated bleed the glucagon levels were 21 (15-31) pmol/L in the F-group and 15 (9-21) pmol/L in the G-group (P < 0.01). After the simulated bleed, arterial ammonia levels increased in both groups [F-group: 73-118 μmol/L (P = 0.01); G-group 64-87 μmol/L (P = 0.01)]. The enhancement of hyperammonaemia was significantly higher in the F-group (45 [19-71] μmol/L) compared with the G-group (23 [13-39] μmol/L) (P = 0.01). The difference in renal ammoniagenesis during the simulated bleed in the F-group was 399 (260-655) nmol/kg/bwt/min and was significantly higher than in the G-group 313 (1-498) nmol/kg/bwt/min (P = 0.05). CONCLUSIONS Overnight glucose infusion results in reduced renal ammoniagenesis and attenuates ammonia levels. These observations have implications for the development of nutritional strategies in hyperammonaemic patients.
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Affiliation(s)
- L Mpabanzi
- Department of Surgery, Maastricht University Medical Centre, NUTRIM School of Nutrition, Toxicology and Metabolism, Maastricht University, The Netherlands
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Malaguarnera M, Vacante M, Giordano M, Pennisi G, Bella R, Rampello L, Malaguarnera M, Li Volti G, Galvano F. Oral acetyl-L-carnitine therapy reduces fatigue in overt hepatic encephalopathy: a randomized, double-blind, placebo-controlled study. Am J Clin Nutr 2011; 93:799-808. [PMID: 21310833 DOI: 10.3945/ajcn.110.007393] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Fatigue is frequently reported in hepatic encephalopathy (HE) and may be related to hyperammonemia. Acetyl-L-carnitine (ALC) offers neuroprotective benefits and improves mitochondrial energetics and function. OBJECTIVE This study evaluated the effect of exogenous ALC on physical and mental fatigue, fatigue severity, and physical activity in patients with mild and moderate hepatoencephalopathy (HE1 and HE2, respectively). DESIGN A total of 121 patients with overt HE were recruited to the study and were subdivided into 2 groups according to their initial HE grade [HE1 (n = 61) or HE2 (n = 60)]. Thirty-one patients with HE1 and 30 with HE2 received 2 g ALC, and 30 patients with HE1 and 30 patients with HE2 received placebo twice a day for 90 d. All patients underwent clinical and laboratory assessments and automated electroencephalogram analysis. RESULTS At the end of the study period, the ALC-treated patients in the HE1 group showed significantly better improvement than did the placebo group in mental fatigue score (-1.7 compared with -0.3; P < 0.05), the fatigue severity scale (-6.4 compared with 2.3; P < 0.001), 7-d Physical Activity Recall questionnaire score (17.1 compared with -2.5; P < 0.001), and Short Physical Performance Battery (2.1 compared with 0.2; P < 0.001); the HE2 group showed significantly better improvement in the fatigue severity scale (-8.1 compared with -5.1; P < 0.001) and 6-min walk test (19.9 compared with 2.3; P < 0.05). Significant decreases in NH(4)(+) were observed in both groups (P < 0.001). CONCLUSION Patients with HE treated with ALC showed a decrease in the severity of both mental and physical fatigue and an increase in physical activity. This trial was registered at clinicaltrials.gov as NCT01223742.
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Affiliation(s)
- Michele Malaguarnera
- Department of Biological Chemistry, Medical Chemistry, and Molecular Biology, University of Catania, Italy.
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Wright G, Noiret L, Olde Damink SWM, Jalan R. Interorgan ammonia metabolism in liver failure: the basis of current and future therapies. Liver Int 2011; 31:163-75. [PMID: 20673233 DOI: 10.1111/j.1478-3231.2010.02302.x] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Hepatic encephalopathy complicates the course of both acute and chronic liver disease and its treatment remains an unmet clinical need. Ammonia is thought to be central in its pathogenesis and remains an important target of current and future therapeutic approaches. In liver failure, the main detoxification pathway of ammonia metabolism is compromised leading to hyperammonaemia. In this situation, the other ammonia-regulating pathways in multiple organs assume important significance. The present review focuses upon interorgan ammonia metabolism in health and disease describing the role of the key enzymes, glutamine synthase and glutaminase. Better understanding of these alternative pathways are leading to the development of new therapeutic approaches.
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Affiliation(s)
- Gavin Wright
- UCL Institute of Hepatology, Division of Medicine, University College London, London, UK
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Ytrebø LM, Kristiansen RG, Maehre H, Fuskevåg OM, Kalstad T, Revhaug A, Cobos MJ, Jalan R, Rose CF, Deutz NEP, Jalan R, Revhaug A. L-ornithine phenylacetate attenuates increased arterial and extracellular brain ammonia and prevents intracranial hypertension in pigs with acute liver failure. Hepatology 2009; 50:165-74. [PMID: 19554542 DOI: 10.1002/hep.22917] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
UNLABELLED Hyperammonemia is a feature of acute liver failure (ALF), which is associated with increased intracranial pressure (ICP) and brain herniation. We hypothesized that a combination of L-ornithine and phenylacetate (OP) would synergistically reduce toxic levels of ammonia by (1) L-ornithine increasing glutamine production (ammonia removal) through muscle glutamine synthetase and (2) phenylacetate conjugating with the ornithine-derived glutamine to form phenylacetylglutamine, which is excreted into the urine. The aims of this study were to determine the effect of OP on arterial and extracellular brain ammonia concentrations as well as ICP in pigs with ALF (induced by liver devascularization). ALF pigs were treated with OP (L-ornithine 0.07 g/kg/hour intravenously; phenylbutyrate, prodrug for phenylacetate; 0.05 g/kg/hour intraduodenally) for 8 hours following ALF induction. ICP was monitored throughout, and arterial and extracellular brain ammonia were measured along with phenylacetylglutamine in the urine. Compared with ALF + saline pigs, treatment with OP significantly attenuated concentrations of arterial ammonia (589.6 +/- 56.7 versus 365.2 +/- 60.4 mumol/L [mean +/- SEM], P= 0.002) and extracellular brain ammonia (P= 0.01). The ALF-induced increase in ICP was prevented in ALF + OP-treated pigs (18.3 +/- 1.3 mmHg in ALF + saline versus 10.3 +/- 1.1 mmHg in ALF + OP-treated pigs;P= 0.001). The value of ICP significantly correlated with the concentration of extracellular brain ammonia (r(2) = 0.36,P< 0.001). Urine phenylacetylglutamine levels increased to 4.9 +/- 0.6 micromol/L in ALF + OP-treated pigs versus 0.5 +/- 0.04 micromol/L in ALF + saline-treated pigs (P< 0.001). CONCLUSION L-Ornithine and phenylacetate act synergistically to successfully attenuate increases in arterial ammonia, which is accompanied by a significant decrease in extracellular brain ammonia and prevention of intracranial hypertension in pigs with ALF.
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Affiliation(s)
- Lars Marius Ytrebø
- Department of Anesthesiology, University Hospital of North Norway and University of Tromsø, Norway.
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Transjugular intrahepatic portosystemic shunts in hemodialysis-dependent patients and patients with advanced renal insufficiency: safety, caution, and encephalopathy. J Vasc Interv Radiol 2008; 19:516-20. [PMID: 18375295 DOI: 10.1016/j.jvir.2007.11.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2007] [Revised: 11/11/2007] [Accepted: 11/15/2007] [Indexed: 01/31/2023] Open
Abstract
PURPOSE To retrospectively determine the acute safety and chronic outcomes of transjugular intrahepatic portosystemic shunt (TIPS) creation in patients with hemodialysis-dependent end-stage renal disease for control of bleeding and refractory ascites. MATERIALS AND METHODS Four dialysis-dependent patients and one renal transplant recipient (glomerular filtration rate, 27 mL/min) underwent TIPS creation for treatment of refractory ascites (n = 3) and recurrent portal hypertensive bleeding (n = 1). A sixth patient developed unrelated renal failure 3 years after initial TIPS formation and presented with encephalopathy at that time. All had nearly normal liver function test results and no previous baseline encephalopathy. Three dialysis recipients underwent dialysis immediately after the TIPS procedure in an intensive care unit; one did not. RESULTS There were no complications of fluid overload or pulmonary edema after TIPS creation in the patients who immediately underwent dialysis. The one patient in whom dialysis was delayed developed respiratory failure and shock liver (ie, ischemic hepatitis). Ascites resolved in all three patients, and no recurrent variceal bleeding occurred during a mean follow-up of 17 months. Severe, grade 2-4 hepatic encephalopathy developed in all patients; in one patient, its onset was delayed until the onset of renal failure 3 years after the original TIPS procedure. Shunt reduction was required in four cases and competitive variceal embolization was required in one to reduce portosystemic diversion. No less than grade 1 episodic baseline encephalopathy was present in all patients despite continued use of the maximum prescribed medical therapy thereafter. CONCLUSIONS TIPS creation is effective in controlling ascites and bleeding in functionally anephric patients, but at the cost of marked and disproportionate hepatic encephalopathy. Prompt, acute postprocedural dialysis and fluid management is critical for safe creation of a TIPS in dialysis-dependent patients.
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Sörös P, Böttcher J, Weissenborn K, Selberg O, Müller MJ. Malnutrition and hypermetabolism are not risk factors for the presence of hepatic encephalopathy: a cross-sectional study. J Gastroenterol Hepatol 2008; 23:606-10. [PMID: 18005013 DOI: 10.1111/j.1440-1746.2007.05222.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND AND AIM Hepatic encephalopathy is a frequent complication of cirrhosis. The present retrospective investigation was conducted to characterize metabolic alterations in cirrhotic patients with and without hepatic encephalopathy. We tested the hypothesis that reduced nutritional status or the degree of tissue catabolism are associated with the presence of hepatic encephalopathy. METHODS We investigated 223 patients with histologically confirmed nonalcoholic cirrhosis without hepatic encephalopathy and with hepatic encephalopathy (grades 1-3). To assess liver function, nutritional status, and energy metabolism, a variety of biochemical and clinical tests were performed including anthropometric measurements, bioelectrical impedance analysis, and indirect calorimetry. RESULTS Nutritional status and tissue catabolism were not significantly different between patients with and without hepatic encephalopathy. CONCLUSIONS Our data do not support the hypothesis that malnutrition or tissue catabolism are independent risk factors for the presence of hepatic encephalopathy in patients with nonalcoholic cirrhosis.
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Affiliation(s)
- Peter Sörös
- Department of Imaging Research, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
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Abstract
Patients experiencing acute elevations of ammonia present to the ICU with encephalopathy, which may progress quickly to cerebral herniation. Patient survival requires immediate treatment of intracerebral hypertension and the reduction of ammonia levels. When hyperammonemia is not thought to be the result of liver failure, treatment for an occult disorder of metabolism must begin prior to the confirmation of an etiology. This article reviews ammonia metabolism, the effects of ammonia on the brain, the causes of hyperammonemia, and the diagnosis of inborn errors of metabolism in adult patients.
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Affiliation(s)
- Alison S Clay
- Department of Surgery and Medicine, Duke University Medical Center, Box 2945, Durham, NC 27710, USA.
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Abstract
OBJECTIVE Cognitive impairment is a common problem in patients with liver cirrhosis. Its pathogenesis is multifactorial and ammonia is considered to play a central role. Renal function has been shown to be important for ammonia metabolism in cirrhosis. Although renal dysfunction is common in cirrhotic patients, its effect on cognitive function is largely unexplored. MATERIAL AND METHODS A total of 128 consecutive cirrhotic patients were prospectively evaluated for the presence of cognitive dysfunction according to the West-Haven criteria and by means of two psychometric tests. Serum creatinine, sodium and potassium as well as plasma ammonia concentrations were assessed. Glomerular filtration rate was also measured by (51)Cr- EDTA clearance in a subgroup of patients. RESULTS Forty-one patients (32%) were found to have cognitive dysfunction (clinical evaluation and/or psychometric tests). Sixteen patients (13%) found with serum creatinine levels above reference values had cognitive dysfunction more frequently than patients with creatinine within the normal range (69% versus 31%; p = 0.001), but did not differ in aetiology or severity of cirrhosis (p >0.1). Patients with loop diuretics versus without did not differ in creatinine values (p >0.1). Multivariate analysis showed that cognitive dysfunction was related to hospital admission at inclusion in the study, international normalized ratio and serum creatinine (p <0.05 for all), but not to potassium or sodium levels. Plasma ammonia concentration was related to serum creatinine (r = 0.26, p = 0.004) and the glomerular filtration rate (r = -0.44, p = 0.023). CONCLUSIONS Renal dysfunction seems to be related to cognitive impairment in patients with liver cirrhosis and might be implicated in the pathogenesis of hepatic encephalopathy.
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Affiliation(s)
- Evangelos Kalaitzakis
- Section of Gastroenterology and Hepatology, Department of Internal Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden.
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Jalan R, Bernuau J. Induction of cerebral hyperemia by ammonia plus endotoxin: does hyperammonemia unlock the blood-brain barrier? J Hepatol 2007; 47:168-71. [PMID: 17566590 DOI: 10.1016/j.jhep.2007.05.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Dejong CHC, van de Poll MCG, Soeters PB, Jalan R, Olde Damink SWM. Aromatic amino acid metabolism during liver failure. J Nutr 2007; 137:1579S-1585S; discussion 1597S-1598S. [PMID: 17513430 DOI: 10.1093/jn/137.6.1579s] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Liver failure is associated with hepatic encephalopathy (HE). An imbalance in plasma levels of aromatic amino acids (AAA) phenylalanine, tyrosine, and tryptophan and branched chain amino acids (BCAA) and their BCAA/AAA ratio has been suggested to play a causal role in HE by enhanced brain AAA uptake and subsequently disturbed neurotransmission. Until recently, data on this subject and the role of the liver and splanchnic bed were scarce, particularly in humans, due to inaccessibility of portal and hepatic veins. Here, we discuss, against a background of relevant literature, data obtained in patients undergoing liver resection or with a transjugular intrahepatic portasystemic stent shunt (TIPSS), where these veins are accessible. The BCAA/AAA ratio remained unchanged after major liver resection, but plasma AAA levels were inversely correlated (P < 0.001) with residual liver volume, in keeping with the observed hepatic AAA uptake. In patients with stable cirrhosis and a TIPSS, the plasma BCAA/AAA ratio was lower than in controls (1.19 +/- 0.09 vs. controls: 3.63 +/- 0.34). Gastrointestinal bleeding in cirrhotics with a TIPSS induced disturbances in BCAA levels and the BCAA/AAA ratio and induced catabolism, which could partly be corrected by isoleucine administration. AAA may be important in the pathogenesis of HE, but it is unlikely that they are the sole factors. HE most likely is a syndrome with multifactorial pathogenesis, where hyperammonemia, AAA/BCAA imbalances, inflammation, brain edema, and neurotransmitter changes interact. Novel therapies to normalize AAA levels in patients with liver failure (such as the molecular adsorbent recirculating system dialysis device) should probably be combined with supplementation of e.g. isoleucine and enhancing ammonia excretion by the kidneys.
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Affiliation(s)
- Cornelis H C Dejong
- Department of Surgery, Nutrition and Toxicology Institute Maastricht, Maastricht University, the Netherlands.
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