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Borsakova DV, Koleva LD, Protasov ES, Ataullakhanov FI, Sinauridze EI. Ammonium removal by erythrocyte-bioreactors based on glutamate dehydrogenase from Proteus sp. jointly with porcine heart alanine aminotransferase. Sci Rep 2022; 12:5437. [PMID: 35361872 PMCID: PMC8971454 DOI: 10.1038/s41598-022-09435-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 03/14/2022] [Indexed: 11/26/2022] Open
Abstract
Excessive ammonium blood concentration causes many serious neurological complications. The medications currently used are not very effective. To remove ammonium from the blood, erythrocyte-bioreactors containing enzymes that processing ammonium have been proposed. The most promising bioreactor contained co-encapsulated glutamate dehydrogenase (GDH) and alanine aminotransferase (ALT). However, a low encapsulation of a commonly used bovine liver GDH (due to high aggregation), makes clinical use of such bioreactors impossible. In this study, new bioreactors containing ALT and non-aggregating GDH at higher loading were first produced using the flow dialysis method and the new bacterial GDH enzyme from Proteus sp. The efficacy of these erythrocyte-bioreactors and their properties (hemolysis, osmotic fragility, intracellular and extracellular activity of included enzymes, erythrocyte indices, and filterability) were studied and compared with native cells during 1-week storage. The ammonium removal rate in vitro by such erythrocyte-bioreactors increased linearly with an increase in encapsulated GDH activity. Alanine in vitro increased in accordance with ammonium consumption, which indicated the joint functioning of both included enzymes. Thus, novel bioreactors for ammonium removal containing GDH from Proteus sp. are promising for clinical use, since they have a more efficient GDH encapsulation and their properties are not inferior to previously obtained erythrocyte-bioreactors.
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Affiliation(s)
- Daria V Borsakova
- Laboratory of Physiology and Biophysics of the Cell, Center for Theoretical Problems of Physicochemical Pharmacology, Russian Academy of Sciences, Srednyaya Kalitnikovskaya str., 30, Moscow, 109029, Russia.,Laboratory of Biophysics, Dmitriy Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, Ministry of Healthcare, Samory Mashela str., 1, GSP-7, Moscow, 117198, Russia
| | - Larisa D Koleva
- Laboratory of Physiology and Biophysics of the Cell, Center for Theoretical Problems of Physicochemical Pharmacology, Russian Academy of Sciences, Srednyaya Kalitnikovskaya str., 30, Moscow, 109029, Russia.,Laboratory of Biophysics, Dmitriy Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, Ministry of Healthcare, Samory Mashela str., 1, GSP-7, Moscow, 117198, Russia
| | - Evgeniy S Protasov
- Laboratory of Physiology and Biophysics of the Cell, Center for Theoretical Problems of Physicochemical Pharmacology, Russian Academy of Sciences, Srednyaya Kalitnikovskaya str., 30, Moscow, 109029, Russia.,Laboratory of Biophysics, Dmitriy Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, Ministry of Healthcare, Samory Mashela str., 1, GSP-7, Moscow, 117198, Russia.,Department of Physics, Lomonosov Moscow State University, Leninskie Gory, 1, build. 2, GSP-1, Moscow, 119991, Russia
| | - Fazoil I Ataullakhanov
- Laboratory of Physiology and Biophysics of the Cell, Center for Theoretical Problems of Physicochemical Pharmacology, Russian Academy of Sciences, Srednyaya Kalitnikovskaya str., 30, Moscow, 109029, Russia.,Laboratory of Biophysics, Dmitriy Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, Ministry of Healthcare, Samory Mashela str., 1, GSP-7, Moscow, 117198, Russia.,Department of Physics, Lomonosov Moscow State University, Leninskie Gory, 1, build. 2, GSP-1, Moscow, 119991, Russia.,Department of Molecular and Translational Medicine, Moscow Institute of Physics and Technology, Institutskiy Per., 9, Dolgoprudny, Moscow Region, 141701, Russia
| | - Elena I Sinauridze
- Laboratory of Physiology and Biophysics of the Cell, Center for Theoretical Problems of Physicochemical Pharmacology, Russian Academy of Sciences, Srednyaya Kalitnikovskaya str., 30, Moscow, 109029, Russia. .,Laboratory of Biophysics, Dmitriy Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, Ministry of Healthcare, Samory Mashela str., 1, GSP-7, Moscow, 117198, Russia. .,Dmitriy Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, Samory Mashela str., 1, GSP-7, Moscow, 117997, Russia.
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Butterworth RF. Ammonia Removal by Metabolic Scavengers for the Prevention and Treatment of Hepatic Encephalopathy in Cirrhosis. Drugs R D 2021; 21:123-132. [PMID: 33890246 PMCID: PMC8206241 DOI: 10.1007/s40268-021-00345-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/26/2021] [Indexed: 12/18/2022] Open
Abstract
Effective lowering of circulating ammonia is the mainstay strategy in the prevention and treatment of hepatic encephalopathy in cirrhosis and there is increasing interest in agents with the metabolic potential for the active removal of ammonia by the liver and skeletal muscle by agents including L-ornithine L-aspartate, branched-chain amino acids, as well as the re-purposing of benzoate and phenylacetate currently employed for the control of hyperammonaemia in congenital urea-cycle enzymopathies. Based upon results of multiple systematic reviews with meta-analyses, L-ornithine L-aspartate demonstrably lowers circulating ammonia in patients with cirrhosis with concomitantly improved mental status. Distinct mechanisms responsible include optimisation of hepatic metabolic pathways for ammonia removal as well as direct hepatoprotective effects involving the release of glutathione and of nitric oxide with beneficial effects on hepatic microcirculation. L-ornithine L-aspartate also prevents cirrhosis-related sarcopenia, leading to increased capacity for ammonia removal by skeletal muscle. Branched-chain amino acids continue to be prescribed as nutritional supplements with the potential to result in improvements in liver function. Sodium benzoate, glycerol phenylbutyrate and an analogous compound L-ornithine phenylacetate were also evaluated. Glycerol phenylbutyrate was the only agent with a beneficial effect on both hyperammonaemia and hepatic encephalopathy. None were superior to lactulose for the lowering of blood ammonia.
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Affiliation(s)
- Roger F Butterworth
- Department of Medicine, University of Montreal, 45143 Cabot Trail, Englishtown, NS, B0C 1H0, Canada.
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3
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Abstract
INTRODUCTION Therapeutic enzymes are currently used in the treatment of several diseases. In most cases, the benefits are limited due to poor in vivo stability, immunogenicity, and drug-induced inactivating antibodies. A partial solution to the problem is obtained by masking the therapeutic protein by chemical modifications. Unfortunately, this is not a satisfactory solution because frequent adverse events, including anaphylaxis, can arise. AREA COVERED Among the delivery systems, we focused on red blood cells for the delivery of therapeutic enzymes. Erythrocytes possess a long circulation time, a reduced immunogenicity, there is no need of chemical modifications and the encapsulated enzyme remains active because it is protected by the cell membrane. Here we discuss some representative applications of the preclinical developments of the field. Some of these are currently in clinic, others are approaching the clinic and others are illustrative of the development process. The selected examples are not always the most recent, but they are the most useful for a comparative approach. EXPERT OPINION The results discussed confirm the central role that red blood cells can play in the treatment of several conditions and suggest the benefit in using a natural cellular carrier in terms of pharmacokinetic, biodistribution, safety, and efficacy.
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Affiliation(s)
- Luigia Rossi
- Department of Biomolecular Sciences, University of Urbino , Urbino, Italy.,EryDel SpA , Bresso, Italy
| | - Francesca Pierigè
- Department of Biomolecular Sciences, University of Urbino , Urbino, Italy
| | | | - Mauro Magnani
- Department of Biomolecular Sciences, University of Urbino , Urbino, Italy.,EryDel SpA , Bresso, Italy
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Protasov ES, Borsakova DV, Alexandrovich YG, Korotkov AV, Kosenko EA, Butylin AA, Ataullakhanov FI, Sinauridze EI. Erythrocytes as bioreactors to decrease excess ammonium concentration in blood. Sci Rep 2019; 9:1455. [PMID: 30728433 PMCID: PMC6365525 DOI: 10.1038/s41598-018-37828-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 12/14/2018] [Indexed: 11/09/2022] Open
Abstract
Increased blood ammonium concentrations cause neurological complications. Existing drugs are not always sufficiently effective. Alternatively, erythrocytes-bioreactors (EBRs) loaded with enzymes utilizing ammonium, were suggested for ammonium removal from blood. However all they worked only for a short period of time. The reasons for this were not investigated. In this study, EBR mathematical models were developed and analysed based on the reactions of glycolysis and different enzymes utilizing ammonium, which showed that the efficiency and duration of EBRs' functioning could be limited due to low permeability of the cell membrane for some key substrates and products. A new enzyme system including glutamate dehydrogenase and alanine aminotransferase was proposed and realised experimentally, which was not limited by cell membrane permeability for glutamate and α-ketoglutarate due to creating metabolic pathway where these metabolites were produced and consumed cyclically. New bioreactors removed ammonium in vitro at the rate of 1.5 mmol/h × lRBCs (for human bioreactors) and in vivo in a model of hyperammoniemia in mice at the rate of 2.0 mmol/h × lRBCs (for mouse bioreactors), which correlated with model calculations. Experimental studies proved the proposed mathematical models are correct. Mathematical simulation of erythrocyte-bioreactors opens new opportunities for analysing the efficiency of any enzyme included in erythrocytes.
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Affiliation(s)
- Eugeniy S Protasov
- Dmitriy Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, Ministry of Healthcare, Samory Mashela str., 1, GSP-7, Moscow, 117997, Russia
- Faculty of Physics, Moscow State University, Leninskie Gory, 1, build. 2, GSP-1, Moscow, 119991, Russia
- Center for Theoretical Problems of Physicochemical Pharmacology, Russian Academy of Sciences, Kosygina str., 4, Moscow, 119334, Russia
| | - Daria V Borsakova
- Dmitriy Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, Ministry of Healthcare, Samory Mashela str., 1, GSP-7, Moscow, 117997, Russia
- Center for Theoretical Problems of Physicochemical Pharmacology, Russian Academy of Sciences, Kosygina str., 4, Moscow, 119334, Russia
| | - Yuliya G Alexandrovich
- Dmitriy Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, Ministry of Healthcare, Samory Mashela str., 1, GSP-7, Moscow, 117997, Russia
| | - Anatoliy V Korotkov
- Moscow Institute of Physics and Technology, Institutskiy per., 9, Dolgoprudny, Moscow region, 141701, Russia
| | - Elena A Kosenko
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya str., 3, Pushchino, Moscow region, 142290, Russia
| | - Andrey A Butylin
- Dmitriy Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, Ministry of Healthcare, Samory Mashela str., 1, GSP-7, Moscow, 117997, Russia
- Faculty of Physics, Moscow State University, Leninskie Gory, 1, build. 2, GSP-1, Moscow, 119991, Russia
| | - Fazoil I Ataullakhanov
- Dmitriy Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, Ministry of Healthcare, Samory Mashela str., 1, GSP-7, Moscow, 117997, Russia
- Faculty of Physics, Moscow State University, Leninskie Gory, 1, build. 2, GSP-1, Moscow, 119991, Russia
- Center for Theoretical Problems of Physicochemical Pharmacology, Russian Academy of Sciences, Kosygina str., 4, Moscow, 119334, Russia
- Moscow Institute of Physics and Technology, Institutskiy per., 9, Dolgoprudny, Moscow region, 141701, Russia
| | - Elena I Sinauridze
- Dmitriy Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, Ministry of Healthcare, Samory Mashela str., 1, GSP-7, Moscow, 117997, Russia.
- Center for Theoretical Problems of Physicochemical Pharmacology, Russian Academy of Sciences, Kosygina str., 4, Moscow, 119334, Russia.
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Komine R, Minamimura K, Watanabe A, Shimizu A, Mori K, Hirata T, Kobayashi T, Akatsuka S. Sudden development of adult-onset type II citrullinemia after total gastrectomy: a case report. Surg Case Rep 2018; 4:11. [PMID: 29368097 PMCID: PMC5783980 DOI: 10.1186/s40792-018-0420-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 01/15/2018] [Indexed: 11/10/2022] Open
Abstract
Background Adult-onset type II citurullinemia is an autosomal recessive disorder characterized by recurrent encephalopathy with hyperammonemia resulting from high plasma citrulline and ammonium levels. This report describes a rare case of adult-onset type II citurullinemia that occurred in a patient who only had the heterozygote mutation, and had never presented with any symptoms before surgery. Case presentation A 56-year-old man underwent a total gastrectomy for stomach cancer. On postoperative Day 13, he suddenly developed presyncope, and blood tests showed hyperammonemia and high levels of serum citrulline. He was diagnosed with hepatic encephalopathy. DNA analysis revealed a heterozygote mutation in Solute Carrier Family 25. Although the patient received a conservative treatment, episodes of loss of consciousness and abnormality of behavior repeatedly occurred. Conclusion Abdominal surgery involving the reconstruction of digestive tract alters the mechanisms of absorption and/or metabolism such that the symptoms of adult-onset type II citurullinemia may arise. Liver transplantation should be performed if all conservative treatments are unsuccessful.
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Affiliation(s)
- Ryuji Komine
- Department of Gastrointestinal and General Surgery, Mitsui Memorial Hospital, 1, Izumi-cho, Kanda, Chiyoda-ku, Tokyo, 101-8643, Japan.
| | - Keisuke Minamimura
- Department of Gastrointestinal and General Surgery, Mitsui Memorial Hospital, 1, Izumi-cho, Kanda, Chiyoda-ku, Tokyo, 101-8643, Japan
| | - Akihiro Watanabe
- Department of Gastrointestinal and General Surgery, Mitsui Memorial Hospital, 1, Izumi-cho, Kanda, Chiyoda-ku, Tokyo, 101-8643, Japan
| | - Atushi Shimizu
- Department of Gastrointestinal and General Surgery, Mitsui Memorial Hospital, 1, Izumi-cho, Kanda, Chiyoda-ku, Tokyo, 101-8643, Japan
| | - Kazuhiko Mori
- Department of Gastrointestinal and General Surgery, Mitsui Memorial Hospital, 1, Izumi-cho, Kanda, Chiyoda-ku, Tokyo, 101-8643, Japan
| | - Toru Hirata
- Department of Gastrointestinal and General Surgery, Mitsui Memorial Hospital, 1, Izumi-cho, Kanda, Chiyoda-ku, Tokyo, 101-8643, Japan
| | - Takashi Kobayashi
- Department of Gastrointestinal and General Surgery, Mitsui Memorial Hospital, 1, Izumi-cho, Kanda, Chiyoda-ku, Tokyo, 101-8643, Japan
| | - Sotaro Akatsuka
- Department of Medical Oncology, Mitsui Memorial Hospital, 1, Izumi-cho, Kanda, Chiyoda-ku, Tokyo, 101-8643, Japan
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Tang L, Chen L, Wang H, Dai L, Pan S. Case report: An adult-onset type II citrin deficiency patient in the emergency department. Exp Ther Med 2016; 12:410-414. [PMID: 27347070 DOI: 10.3892/etm.2016.3298] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Accepted: 04/12/2016] [Indexed: 11/05/2022] Open
Abstract
Mutations in the solute carrier family 25 (SLC25A13) gene may result in neonatal intrahepatic cholestasis caused by citrin deficiency and/or adult-onset type II citrullinemia. These conditions are inherited in an autosomal recessive manner. The current case report describes a 43-year-old man who presented with sudden delirium and upper limb weakness. Upon admission, the patient was fully conscious and alert but later lost consciousness subsequent to a sudden convulsive seizure. Hyperammonemia was detected and analysis of the SLC25A13 gene identified an 851del4 mutation. Thus, the possibility of genetic disease should be considered as a potential cause of the symptoms of patients with altered states of consciousness, such as delirium and loss of consciousness, in cases where the cause of the disturbance is unknown.
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Affiliation(s)
- Lujia Tang
- Emergency Department, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, P.R. China
| | - Liang Chen
- Emergency Department, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, P.R. China
| | - Hairong Wang
- Emergency Department, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, P.R. China
| | - Lihua Dai
- Emergency Department, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, P.R. China
| | - Shuming Pan
- Emergency Department, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, P.R. China
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7
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Ghallab A, Cellière G, Henkel SG, Driesch D, Hoehme S, Hofmann U, Zellmer S, Godoy P, Sachinidis A, Blaszkewicz M, Reif R, Marchan R, Kuepfer L, Häussinger D, Drasdo D, Gebhardt R, Hengstler JG. Model-guided identification of a therapeutic strategy to reduce hyperammonemia in liver diseases. J Hepatol 2016; 64:860-71. [PMID: 26639393 DOI: 10.1016/j.jhep.2015.11.018] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 11/15/2015] [Accepted: 11/16/2015] [Indexed: 01/09/2023]
Abstract
BACKGROUND & AIMS Recently, spatial-temporal/metabolic mathematical models have been established that allow the simulation of metabolic processes in tissues. We applied these models to decipher ammonia detoxification mechanisms in the liver. METHODS An integrated metabolic-spatial-temporal model was used to generate hypotheses of ammonia metabolism. Predicted mechanisms were validated using time-resolved analyses of nitrogen metabolism, activity analyses, immunostaining and gene expression after induction of liver damage in mice. Moreover, blood from the portal vein, liver vein and mixed venous blood was analyzed in a time dependent manner. RESULTS Modeling revealed an underestimation of ammonia consumption after liver damage when only the currently established mechanisms of ammonia detoxification were simulated. By iterative cycles of modeling and experiments, the reductive amidation of alpha-ketoglutarate (α-KG) via glutamate dehydrogenase (GDH) was identified as the lacking component. GDH is released from damaged hepatocytes into the blood where it consumes ammonia to generate glutamate, thereby providing systemic protection against hyperammonemia. This mechanism was exploited therapeutically in a mouse model of hyperammonemia by injecting GDH together with optimized doses of cofactors. Intravenous injection of GDH (720 U/kg), α-KG (280 mg/kg) and NADPH (180 mg/kg) reduced the elevated blood ammonia concentrations (>200 μM) to levels close to normal within only 15 min. CONCLUSION If successfully translated to patients the GDH-based therapy might provide a less aggressive therapeutic alternative for patients with severe hyperammonemia.
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Affiliation(s)
- Ahmed Ghallab
- Leibniz Research Centre for Working Environment and Human Factors at the Technical University Dortmund, Dortmund, Germany; Department of Forensic Medicine and Toxicology, Faculty of Veterinary Medicine, South Valley University, Qena, Egypt.
| | - Géraldine Cellière
- Sorbonne Universités, Inria, UPMC Univ Paris 06, Lab. J.L. Lions UMR CNRS 7598, Paris, France
| | | | | | - Stefan Hoehme
- Institute of Computer Science and Interdisciplinary Centre for Bioinformatics, University of Leipzig, Leipzig, Germany
| | - Ute Hofmann
- Dr. Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tuebingen, Germany
| | - Sebastian Zellmer
- Institute of Biochemistry, Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | - Patricio Godoy
- Leibniz Research Centre for Working Environment and Human Factors at the Technical University Dortmund, Dortmund, Germany
| | - Agapios Sachinidis
- Institute of Neurophysiology and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Robert-Koch-Str. 39, 50931 Cologne, Germany
| | - Meinolf Blaszkewicz
- Leibniz Research Centre for Working Environment and Human Factors at the Technical University Dortmund, Dortmund, Germany
| | - Raymond Reif
- Leibniz Research Centre for Working Environment and Human Factors at the Technical University Dortmund, Dortmund, Germany
| | - Rosemarie Marchan
- Leibniz Research Centre for Working Environment and Human Factors at the Technical University Dortmund, Dortmund, Germany
| | - Lars Kuepfer
- Computational Systems Biology, Bayer Technology Services GmbH, Leverkusen, Germany
| | - Dieter Häussinger
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Düsseldorf, Germany
| | - Dirk Drasdo
- Sorbonne Universités, Inria, UPMC Univ Paris 06, Lab. J.L. Lions UMR CNRS 7598, Paris, France; Institute of Computer Science and Interdisciplinary Centre for Bioinformatics, University of Leipzig, Leipzig, Germany
| | - Rolf Gebhardt
- Institute of Biochemistry, Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | - Jan G Hengstler
- Leibniz Research Centre for Working Environment and Human Factors at the Technical University Dortmund, Dortmund, Germany.
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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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Szucs Z, Sathekge M, Marjanovic-Painter B, Wagener J, Sello T, Wagener C, Zeevaart JR. Synthesis of I-131 labelled 4-iodophenylacetic acid. J Labelled Comp Radiopharm 2010. [DOI: 10.1002/jlcr.1812] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Moriyama M, Li MX, Kobayashi K, Sinasac DS, Kannan Y, Iijima M, Horiuchi M, Tsui LC, Tanaka M, Nakamura Y, Saheki T. Pyruvate ameliorates the defect in ureogenesis from ammonia in citrin-deficient mice. J Hepatol 2006; 44:930-8. [PMID: 16458993 DOI: 10.1016/j.jhep.2005.09.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2005] [Revised: 08/02/2005] [Accepted: 09/14/2005] [Indexed: 12/04/2022]
Abstract
BACKGROUND/AIMS Mutations in SLC25A13, encoding the mitochondrial aspartate-glutamate carrier citrin, cause adult-onset type II citrullinemia (CTLN2) in humans. We have previously reported that although citrin-knockout (Ctrn-/-) mice fail to display symptoms of CTLN2, liver perfusion revealed a deficit in ureogenesis from ammonia accompanied by an increase in the perfusate lactate-to-pyruvate (L/P) ratio. The present study explores the effects of pyruvate, aspartate and citrate on improving the abnormalities observed in the Ctrn-/- liver. METHODS We measured the rate of ureogenesis from ammonium chloride using the liver-perfusion system. RESULTS Pyruvate infusion lowered the L/P ratio and corrected the deficit in ureogenesis in the Ctrn-/- liver. This effect was found to be dose-dependent in both instances. Phenazine methosulfate, a cytosolic oxidant, also improved the rate of ureogenesis in the Ctrn-/- liver and led to a fall in the L/P ratio. The addition of aspartate or citrate did not change either the rate of ureogenesis or the L/P ratio in the Ctrn-/- liver. CONCLUSIONS Citrin deficiency disturbs urea synthesis primarily as a result of an elevated cytosolic NADH/NAD+ ratio owing to limited reoxidation of reducing equivalents. Clinically, pyruvate may have a therapeutic benefit for CTLN2 patients.
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Affiliation(s)
- Mitsuaki Moriyama
- Laboratory of Integrative Physiology in Veterinary Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, Osaka 599-8531, Japan
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Saheki T, Kobayashi K, Iijima M, Horiuchi M, Begum L, Jalil MA, Li MX, Lu YB, Ushikai M, Tabata A, Moriyama M, Hsiao KJ, Yang Y. Adult-onset type II citrullinemia and idiopathic neonatal hepatitis caused by citrin deficiency: involvement of the aspartate glutamate carrier for urea synthesis and maintenance of the urea cycle. Mol Genet Metab 2004; 81 Suppl 1:S20-6. [PMID: 15050970 DOI: 10.1016/j.ymgme.2004.01.006] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2003] [Revised: 10/04/2003] [Accepted: 10/21/2003] [Indexed: 10/26/2022]
Abstract
Citrin is a mitochondrial aspartate glutamate carrier primarily expressed in the liver, heart, and kidney. We found that adult-onset type II citrullinemia is caused by mutations in the SLC25A13 gene that encodes for citrin. In this report, we describe the frequency of SLC25A13 mutations, the roles of citrin as a member of the urea cycle and as a member of the malate-aspartate shuttle, the relationship between its functions and symptoms of citrin deficiency, and therapeutic issues.
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Affiliation(s)
- Takeyori Saheki
- Department of Molecular Metabolism and Biochemical Genetics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan.
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