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Yap S, Lamireau D, Feillet F, Ruiz Gomez A, Davison J, Tangeraas T, Giordano V. Real-World Experience of Carglumic Acid for Methylmalonic and Propionic Acidurias: An Interim Analysis of the Multicentre Observational PROTECT Study. Drugs R D 2024; 24:69-80. [PMID: 38198106 PMCID: PMC11035519 DOI: 10.1007/s40268-023-00449-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/30/2023] [Indexed: 01/11/2024] Open
Abstract
BACKGROUND AND OBJECTIVE Methylmalonic aciduria (MMA) and propionic aciduria (PA) are organic acidurias characterised by the accumulation of toxic metabolites and hyperammonaemia related to secondary N-acetylglutamate deficiency. Carglumic acid, a synthetic analogue of N-acetylglutamate, decreases ammonia levels by restoring the functioning of the urea cycle. However, there are limited data available on the long-term safety and effectiveness of carglumic acid. Here, we present an interim analysis of the ongoing, long-term, prospective, observational PROTECT study (NCT04176523), which is investigating the long-term use of carglumic acid in children and adults with MMA and PA. METHODS Individuals with MMA or PA from France, Germany, Italy, Norway, Spain, Sweden and the UK who have received at least 1 year of carglumic acid treatment as part of their usual care are eligible for inclusion. The primary objective is the number and duration of acute metabolic decompensation events with hyperammonaemia (ammonia level >159 µmol/L during a patient's first month of life or >60 µmol/L thereafter, with an increased lactate level [> 1.8 mmol/L] and/or acidosis [pH < 7.35]) before and after treatment with carglumic acid. Peak plasma ammonia levels during the last decompensation event before and the first decompensation event after carglumic acid initiation, and the annualised rate of decompensation events before and after treatment initiation are also being assessed. Secondary objectives include the duration of hospital stay associated with decompensation events. Data are being collected at approximately 12 months' and 18 months' follow-up. RESULTS Of the patients currently enrolled in the PROTECT study, data from ten available patients with MMA (n = 4) and PA (n = 6) were analysed. The patients had received carglumic acid for 14-77 (mean 36) months. Carglumic acid reduced the median peak ammonia level of the total patient population from 250 µmol/L (range 97-2569) before treatment to 103 µmol/L (range 97-171) after treatment. The annualised rate of acute metabolic decompensations with hyperammonaemia was reduced by a median of - 41% (range - 100% to + 60%) after treatment with carglumic acid. Of the five patients who experienced a decompensation event before treatment and for whom a post-treatment rate could be calculated, the annualised decompensation event rate was lower after carglumic acid treatment in four patients. The mean duration of hospital inpatient stay during decompensation events was shorter after than before carglumic acid treatment initiation in four of five patients for whom length of stay could be calculated. CONCLUSIONS In this group of patients with MMA and PA, treatment with carglumic acid for at least 1 year reduced peak plasma ammonia levels in the total patient population and reduced the frequency of metabolic decompensation events, as well as the duration of inpatient stay due to metabolic decompensations in a subset of patients. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov, NCT04176523. Registered 25 November, 2019, retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04176523 .
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Affiliation(s)
- Sufin Yap
- Department of Inherited Metabolic Diseases, Sheffield Children's Hospital, Western Bank, Sheffield, S10 2TH, UK.
| | - Delphine Lamireau
- Hopital Des Enfants, CHU de Bordeaux-GH Pellegrin, Bordeaux Cedex, France
| | - Francois Feillet
- CHU de Nancy, Hopitaux de Brabois, Vandoeuvre-les-Nancy Cedex, France
| | | | | | - Trine Tangeraas
- Department of Paediatric and Adolescent Medicine, Oslo University Hospital, Oslo, Norway
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Alfadhel M, Nashabat M, Saleh M, Elamin M, Alfares A, Al Othaim A, Umair M, Ahmed H, Ababneh F, Al Mutairi F, Eyaid W, Alswaid A, Alohali L, Faqeih E, Almannai M, Aljeraisy M, Albdah B, Hussein MA, Rahbeeni Z, Alasmari A. Long-term effectiveness of carglumic acid in patients with propionic acidemia (PA) and methylmalonic acidemia (MMA): a randomized clinical trial. Orphanet J Rare Dis 2021; 16:422. [PMID: 34635114 PMCID: PMC8507242 DOI: 10.1186/s13023-021-02032-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 09/19/2021] [Indexed: 01/14/2023] Open
Abstract
Background Propionic acidemia (PA) and methylmalonic acidemia (MMA) are rare, autosomal recessive inborn errors of metabolism that require life-long medical treatment. The trial aimed to evaluate the effectiveness of the administration of carglumic acid with the standard treatment compared to the standard treatment alone in the management of these organic acidemias.
Methods The study was a prospective, multicenter, randomized, parallel-group, open-label, controlled clinical trial. Patients aged ≤ 15 years with confirmed PA and MMA were included in the study. Patients were followed up for two years. The primary outcome was the number of emergency room (ER) admissions because of hyperammonemia. Secondary outcomes included plasma ammonia levels over time, time to the first episode of hyperammonemia, biomarkers, and differences in the duration of hospital stay. Results Thirty-eight patients were included in the study. On the primary efficacy endpoint, a mean of 6.31 ER admissions was observed for the carglumic acid arm, compared with 12.76 for standard treatment, with a significant difference between the groups (p = 0.0095). Of the secondary outcomes, the only significant differences were in glycine and free carnitine levels. Conclusion Using carglumic acid in addition to standard treatment over the long term significantly reduces the number of ER admissions because of hyperammonemia in patients with PA and MMA. Supplementary Information The online version contains supplementary material available at 10.1186/s13023-021-02032-8.
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Affiliation(s)
- Majid Alfadhel
- Genetics and Precision Medicine department (GPM), King Abdullah Specialized Children's Hospital (KASCH), King Abdullah International Medical Research Center, King Saud Bin Abdulaziz University for Health Sciences (KSAUHS), King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia.
| | - Marwan Nashabat
- Genetics and Precision Medicine department (GPM), King Abdullah Specialized Children's Hospital (KASCH), King Abdullah International Medical Research Center, King Saud Bin Abdulaziz University for Health Sciences (KSAUHS), King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia
| | - Mohammed Saleh
- Medical Genetics Section, King Fahad Medical City, Children's Hospital, Riyadh, Kingdom of Saudi Arabia
| | - Mohammed Elamin
- Medical Genetics Section, King Fahad Medical City, Children's Hospital, Riyadh, Kingdom of Saudi Arabia
| | - Ahmed Alfares
- Department of Pediatrics, College of Medicine, Qassim University, Buraidah, Kingdom of Saudi Arabia
| | - Ali Al Othaim
- Department of Pathology, King Abdullah International Medical Research Centre, King Saud bin Abdulaziz University for Health Science, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (NGHA), Riyadh, Kingdom of Saudi Arabia
| | - Muhammad Umair
- Medical Genomics Research Department, King Abdullah International Medical Research Center (KAIMRC), King Saud bin Abdulaziz University for Health Sciences, King AbdulAziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Kingdom of Saudi Arabia
| | - Hind Ahmed
- Genetics and Precision Medicine department (GPM), King Abdullah Specialized Children's Hospital (KASCH), King Abdullah International Medical Research Center, King Saud Bin Abdulaziz University for Health Sciences (KSAUHS), King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia
| | - Faroug Ababneh
- Genetics and Precision Medicine department (GPM), King Abdullah Specialized Children's Hospital (KASCH), King Abdullah International Medical Research Center, King Saud Bin Abdulaziz University for Health Sciences (KSAUHS), King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia
| | - Fuad Al Mutairi
- Genetics and Precision Medicine department (GPM), King Abdullah Specialized Children's Hospital (KASCH), King Abdullah International Medical Research Center, King Saud Bin Abdulaziz University for Health Sciences (KSAUHS), King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia
| | - Wafaa Eyaid
- Genetics and Precision Medicine department (GPM), King Abdullah Specialized Children's Hospital (KASCH), King Abdullah International Medical Research Center, King Saud Bin Abdulaziz University for Health Sciences (KSAUHS), King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia
| | - Abdulrahman Alswaid
- Genetics and Precision Medicine department (GPM), King Abdullah Specialized Children's Hospital (KASCH), King Abdullah International Medical Research Center, King Saud Bin Abdulaziz University for Health Sciences (KSAUHS), King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia
| | - Lina Alohali
- Genetics and Precision Medicine department (GPM), King Abdullah Specialized Children's Hospital (KASCH), King Abdullah International Medical Research Center, King Saud Bin Abdulaziz University for Health Sciences (KSAUHS), King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia
| | - Eissa Faqeih
- Medical Genetics Section, King Fahad Medical City, Children's Hospital, Riyadh, Kingdom of Saudi Arabia
| | - Mohammed Almannai
- Medical Genetics Section, King Fahad Medical City, Children's Hospital, Riyadh, Kingdom of Saudi Arabia
| | - Majed Aljeraisy
- King Abdullah International Medical Research Centre, College of Pharmacy, King Saud bin Abdulaziz University for Health Science, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs, Riyadh, Kingdom of Saudi Arabia
| | - Bayan Albdah
- Department Biostatistics and Bioinformatics, King Abdullah International Medical Research Centre, King Saud bin Abdulaziz University for Health Science, Ministry of National Guard-Health Affairs, Riyadh, Kingdom of Saudi Arabia
| | - Mohamed A Hussein
- Department Biostatistics and Bioinformatics, King Abdullah International Medical Research Centre, King Saud bin Abdulaziz University for Health Science, Ministry of National Guard-Health Affairs, Riyadh, Kingdom of Saudi Arabia
| | - Zuhair Rahbeeni
- Department of Medical Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Kingdom of Saudi Arabia
| | - Ali Alasmari
- Medical Genetics Section, King Fahad Medical City, Children's Hospital, Riyadh, Kingdom of Saudi Arabia
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Redant S, Empain A, Mugisha A, Kamgang P, Attou R, Honoré PM, De Bels D. Management of late onset urea cycle disorders-a remaining challenge for the intensivist? Ann Intensive Care 2021; 11:2. [PMID: 33409766 PMCID: PMC7788146 DOI: 10.1186/s13613-020-00797-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 12/26/2020] [Indexed: 12/31/2022] Open
Abstract
Background Hyperammonemia caused by a disorder of the urea cycle is a rare cause of metabolic encephalopathy that may be underdiagnosed by the adult intensivists because of its rarity. Urea cycle disorders are autosomal recessive diseases except for ornithine transcarbamylase deficiency (OTCD) that is X-linked. Optimal treatment is crucial to improve prognosis. Main body We systematically reviewed cases reported in the literature on hyperammonemia in adulthood. We used the US National Library of Medicine Pubmed search engine since 2009. The two main causes are ornithine transcarbamylase deficiency followed by type II citrullinemia. Diagnosis by the intensivist remains very challenging therefore delaying treatment and putting patients at risk of fatal cerebral edema. Treatment consists in adapted nutrition, scavenging agents and dialysis. As adults are more susceptible to hyperammonemia, emergent hemodialysis is mandatory before referral to a reference center if ammonia levels are above 200 µmol/l as the risk of cerebral edema is then above 55%. Definitive therapy in urea cycle abnormalities is liver transplantation. Conclusion Awareness of urea cycle disorders in adults intensive care units can optimize early management and accordingly dramatically improve prognosis. By preventing hyperammonemia to induce brain edema and herniation leading to death.
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Affiliation(s)
- S Redant
- Department of Intensive Care, Université Libre de Bruxelles (ULB), CHU Brugmann-Brugmann University Hospital, 4, Place Arthur Van Gehuchten, 1020, Brussels, Belgium
| | - A Empain
- Department of Metabolic Diseases, Hôpital universitaire des enfants reine Fabiola, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - A Mugisha
- Department of Intensive Care, Université Libre de Bruxelles (ULB), CHU Brugmann-Brugmann University Hospital, 4, Place Arthur Van Gehuchten, 1020, Brussels, Belgium
| | - P Kamgang
- Department of Internal Medicine, Brugmann University Hospital, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - R Attou
- Department of Intensive Care, Université Libre de Bruxelles (ULB), CHU Brugmann-Brugmann University Hospital, 4, Place Arthur Van Gehuchten, 1020, Brussels, Belgium
| | - P M Honoré
- Department of Intensive Care, Université Libre de Bruxelles (ULB), CHU Brugmann-Brugmann University Hospital, 4, Place Arthur Van Gehuchten, 1020, Brussels, Belgium.
| | - D De Bels
- Department of Intensive Care, Université Libre de Bruxelles (ULB), CHU Brugmann-Brugmann University Hospital, 4, Place Arthur Van Gehuchten, 1020, Brussels, Belgium
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Nitzahn M, Lipshutz GS. CPS1: Looking at an ancient enzyme in a modern light. Mol Genet Metab 2020; 131:289-298. [PMID: 33317798 PMCID: PMC7738762 DOI: 10.1016/j.ymgme.2020.10.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 10/02/2020] [Accepted: 10/03/2020] [Indexed: 02/06/2023]
Abstract
The mammalian urea cycle (UC) is responsible for siphoning catabolic waste nitrogen into urea for excretion. Disruptions of the functions of any of the enzymes or transporters lead to elevated ammonia and neurological injury. Carbamoyl phosphate synthetase 1 (CPS1) is the first and rate-limiting UC enzyme responsible for the direct incorporation of ammonia into UC intermediates. Symptoms in CPS1 deficiency are typically the most severe of all UC disorders, and current clinical management is insufficient to prevent the associated morbidities and high mortality. With recent advances in basic and translational studies of CPS1, appreciation for this enzyme's essential role in the UC has been broadened to include systemic metabolic regulation during homeostasis and disease. Here, we review recent advances in CPS1 biology and contextualize them around the role of CPS1 in health and disease.
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Affiliation(s)
- Matthew Nitzahn
- Molecular Biology Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA; Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Gerald S Lipshutz
- Molecular Biology Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA; Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA; Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA; Psychiatry, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA; Intellectual and Developmental Disabilities Research Center, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA; Semel Institute for Neuroscience, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
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Breilyn MS, Wasserstein MP. Established and Emerging Treatments for Patients with Inborn Errors of Metabolism. Neoreviews 2020; 21:e699-e707. [PMID: 33004565 DOI: 10.1542/neo.21-10-e699] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Inborn errors of metabolism (IEMs) are inherited defects in a metabolic pathway resulting in clinical disease. The overall goal of therapy is to restore metabolic homeostasis while minimizing the deleterious effects of the interruption. Conventional treatments focus on decreasing substrate, providing product, and replacing deficient enzyme or cofactor. We discuss examples of established, novel, and emerging therapies to provide a framework for understanding the principles of management for patients with IEMs.
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Affiliation(s)
- Margo Sheck Breilyn
- Albert Einstein College of Medicine and the Children's Hospital at Montefiore, Bronx, NY
| | - Melissa P Wasserstein
- Albert Einstein College of Medicine and the Children's Hospital at Montefiore, Bronx, NY
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Palomino Pérez LM, Martín‐Rivada Á, Cañedo Villaroya E, García‐Peñas JJ, Cuervas‐Mons Vendrell M, Pedrón‐Giner C. Use of carglumic acid in valproate-induced hyperammonemia: 25 pediatric cases. JIMD Rep 2020; 55:3-11. [PMID: 32905024 PMCID: PMC7463051 DOI: 10.1002/jmd2.12131] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 04/08/2020] [Accepted: 05/04/2020] [Indexed: 01/09/2023] Open
Abstract
Hyperammonemic encephalopathy is a rare but potentially dangerous complication of the antiepileptic drug (AED) sodium valproate (VPA). We report a retrospective study of 25 pediatric patients, (15 females [60%]; age: 7.6 ± 4.9 years), with different underlying disorders, who suffered from hyperammonemia due to VPA and who were treated with carglumic acid (CA). The duration of treatment with VPA was 15 ± 1 month, with a dose of 40 ± 16.6 mg/kg/d. VPA blood levels were 75.5 ± 60 mg/L with seven patients being overdosed (>100 mg/L). Twenty-three patients received concomitant treatment with other AEDs. The initial dose of CA was 100 mg/kg. Subsequently, CA doses of 25 mg/kg were given to 22 patients every 6 hours (average treatment length 2.17 ± 1.1 days) until ammonemia was normalized. In nine patients, CA was used in combination with other drugs to treat hyperammonemia. In all cases, blood ammonia levels were brought under control and symptoms of hyperammonemia resolved. Two hours after CA administration, the average reduction in ammonium levels was 53 ± 29 and 88.6 ± 47.5 μmol/L at 24 hours, resulting in a statistically significant decrease when compared to pretreatment levels. There were no statistically significant differences between sexes, in the presence or not of cognitive impairment or previous carnitine treatment. There were no statistically significant differences when comparing treatment with CA plus ammonia scavengers vs CA alone. In 17 patients (68%) VPA was discontinued and 62% of the patients who maintained treatment had recurrent episodes of hyperammonemia.
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Affiliation(s)
| | | | - Elvira Cañedo Villaroya
- Section of Gastroenterology and NutritionHospital Infantil Universitario Niño JesúsMadridSpain
| | | | | | - Consuelo Pedrón‐Giner
- Section of Gastroenterology and NutritionHospital Infantil Universitario Niño JesúsMadridSpain
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Galsgaard KD, Pedersen J, Kjeldsen SAS, Winther-Sørensen M, Stojanovska E, Vilstrup H, Ørskov C, Wewer Albrechtsen NJ, Holst JJ. Glucagon receptor signaling is not required for N-carbamoyl glutamate- and l-citrulline-induced ureagenesis in mice. Am J Physiol Gastrointest Liver Physiol 2020; 318:G912-G927. [PMID: 32174131 DOI: 10.1152/ajpgi.00294.2019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Glucagon regulates the hepatic amino acid metabolism and increases ureagenesis. Ureagenesis is activated by N-acetylglutamate (NAG), formed via activation of N-acetylglutamate synthase (NAGS). With the aim to identify the steps whereby glucagon both acutely and chronically regulates ureagenesis, we investigated whether glucagon receptor-mediated activation of ureagenesis is required in a situation where NAGS activity and/or NAG levels are sufficient to activate the first step of the urea cycle in vivo. Female C57BL/6JRj mice treated with a glucagon receptor antagonist (GRA), glucagon receptor knockout (Gcgr-/-) mice, and wild-type (Gcgr+/+) littermates received an intraperitoneal injection of N-carbamoyl glutamate (Car; a stable variant of NAG), l-citrulline (Cit), Car and Cit (Car + Cit), or PBS. In separate experiments, Gcgr-/- and Gcgr+/+ mice were administered N-carbamoyl glutamate and l-citrulline (wCar + wCit) in the drinking water for 8 wk. Car, Cit, and Car + Cit significantly (P < 0.05) increased plasma urea concentrations, independently of pharmacological and genetic disruption of glucagon receptor signaling (P = 0.9). Car increased blood glucose concentrations equally in GRA- and vehicle-treated mice (P = 0.9), whereas the increase upon Car + Cit was impaired in GRA-treated mice (P = 0.008). Blood glucose concentrations remained unchanged in Gcgr-/- mice upon Car (P = 0.2) and Car + Cit (P = 0.9). Eight weeks administration of wCar + wCit did not change blood glucose (P > 0.2), plasma amino acid (P > 0.4), and urea concentrations (P > 0.3) or the area of glucagon-positive cells (P > 0.3) in Gcgr-/- and Gcgr+/+ mice. Our data suggest that glucagon-mediated activation of ureagenesis is not required when NAGS activity and/or NAG levels are sufficient to activate the first step of the urea cycle.NEW & NOTEWORTHY Hepatic ureagenesis is essential in amino acid metabolism and is importantly regulated by glucagon, but the exact mechanism is unclear. With the aim to identify the steps whereby glucagon both acutely and chronically regulates ureagenesis, we here show, contrary to our hypothesis, that glucagon receptor-mediated activation of ureagenesis is not required when N-acetylglutamate synthase activity and/or N-acetylglutamate levels are sufficient to activate the first step of the urea cycle in vivo.
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Affiliation(s)
- Katrine D Galsgaard
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens Pedersen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Endocrinology and Nephrology, Nordsjaellands Hospital Hilleroed, Hilleroed, Denmark
| | - Sasha A S Kjeldsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Marie Winther-Sørensen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Elena Stojanovska
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Hendrik Vilstrup
- Department of Hepatology and Gastroenterology, Aarhus University Hospital, Aarhus, Denmark
| | - Cathrine Ørskov
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nicolai J Wewer Albrechtsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens J Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Nashabat M, Obaid A, Al Mutairi F, Saleh M, Elamin M, Ahmed H, Ababneh F, Eyaid W, Alswaid A, Alohali L, Faqeih E, Aljeraisy M, Hussein MA, Alasmari A, Alfadhel M. Evaluation of long-term effectiveness of the use of carglumic acid in patients with propionic acidemia (PA) or methylmalonic acidemia (MMA): study protocol for a randomized controlled trial. BMC Pediatr 2019; 19:195. [PMID: 31196016 PMCID: PMC6563377 DOI: 10.1186/s12887-019-1571-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 06/04/2019] [Indexed: 01/20/2023] Open
Abstract
Introduction Propionic acidemia (PA) and methylmalonic acidemia (MMA) are rare autosomal recessive inborn errors of metabolism characterized by hyperammonemia due to N-acetylglutamate synthase (NAGS) dysfunction. Carglumic acid (Carbaglu®; Orphan Europe Ltd.) is approved by the US Food and Drug Administration (USFDA) for the treatment of hyperammonemia due hepatic NAGS deficiency. Here we report the rationale and design of a phase IIIb trial that is aimed at determining the long-term efficacy and safety of carglumic acid in the management of PA and MMA. Methods This prospective, multicenter, open-label, randomized, parallel group phase IIIb study will be conducted in Saudi Arabia. Patients with PA or MMA (≤15 years of age) will be randomized 1:1 to receive twice daily carglumic acid (50 mg/kg/day) plus standard therapy (protein-restricted diet, L-carnitine, and metronidazole) or standard therapy alone for a 2-year treatment period. The primary efficacy outcome is the number of emergency room visits due to hyperammonemia. Safety will be assessed throughout the study and during the 1 month follow-up period after the study. Discussion Current guidelines recommend conservative medical treatment as the main strategy for the management of PA and MMA. Although retrospective studies have suggested that long-term carglumic acid may be beneficial in the management of PA and MMA, current literature lacks evidence for this indication. This clinical trial will determine the long-term safety and efficacy of carglumic acid in the management of PA and MMA. Trial registration King Abdullah International Medical Research Center (KAIMRC): (RC13/116) 09/1/2014. Saudi Food and Drug Authority (SFDA) (33066) 08/14/2014. ClinicalTrials.gov (identifier: NCT02426775) 04/22/2015.
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Affiliation(s)
- Marwan Nashabat
- Genetics Division, Department of Pediatrics, King Abdullah International Medical Research Centre, King Saud bin Abdulaziz University for Health Science, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (NGHA), PO Box 22490 11426, Riyadh, Saudi Arabia
| | - Abdulrahman Obaid
- Genetics Division, Department of Pediatrics, King Abdullah International Medical Research Centre, King Saud bin Abdulaziz University for Health Science, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (NGHA), PO Box 22490 11426, Riyadh, Saudi Arabia
| | - Fuad Al Mutairi
- Genetics Division, Department of Pediatrics, King Abdullah International Medical Research Centre, King Saud bin Abdulaziz University for Health Science, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (NGHA), PO Box 22490 11426, Riyadh, Saudi Arabia
| | - Mohammed Saleh
- Medical Genetic Section, King Fahad Medical City, Children's Hospital, Riyadh, Saudi Arabia
| | - Mohammed Elamin
- Medical Genetic Section, King Fahad Medical City, Children's Hospital, Riyadh, Saudi Arabia
| | - Hind Ahmed
- Genetics Division, Department of Pediatrics, King Abdullah International Medical Research Centre, King Saud bin Abdulaziz University for Health Science, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (NGHA), PO Box 22490 11426, Riyadh, Saudi Arabia
| | - Faroug Ababneh
- Genetics Division, Department of Pediatrics, King Abdullah International Medical Research Centre, King Saud bin Abdulaziz University for Health Science, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (NGHA), PO Box 22490 11426, Riyadh, Saudi Arabia
| | - Wafaa Eyaid
- Genetics Division, Department of Pediatrics, King Abdullah International Medical Research Centre, King Saud bin Abdulaziz University for Health Science, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (NGHA), PO Box 22490 11426, Riyadh, Saudi Arabia
| | - Abdulrahman Alswaid
- Genetics Division, Department of Pediatrics, King Abdullah International Medical Research Centre, King Saud bin Abdulaziz University for Health Science, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (NGHA), PO Box 22490 11426, Riyadh, Saudi Arabia
| | - Lina Alohali
- Genetics Division, Department of Pediatrics, King Abdullah International Medical Research Centre, King Saud bin Abdulaziz University for Health Science, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (NGHA), PO Box 22490 11426, Riyadh, Saudi Arabia
| | - Eissa Faqeih
- Medical Genetic Section, King Fahad Medical City, Children's Hospital, Riyadh, Saudi Arabia
| | - Majed Aljeraisy
- King Abdullah International Medical Research Centre, King Saud bin Abdulaziz University for Health Science, College of Pharmacy, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs, Riyadh, Saudi Arabia
| | - Mohamed A Hussein
- Department Biostatistics and Bioinformatics, King Abdullah International Medical Research Centre, King Saud bin Abdulaziz University for Health Science, Ministry of National Guard-Health Affairs, Riyadh, Saudi Arabia
| | - Ali Alasmari
- Medical Genetic Section, King Fahad Medical City, Children's Hospital, Riyadh, Saudi Arabia
| | - Majid Alfadhel
- Genetics Division, Department of Pediatrics, King Abdullah International Medical Research Centre, King Saud bin Abdulaziz University for Health Science, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (NGHA), PO Box 22490 11426, Riyadh, Saudi Arabia.
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9
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Blair HA. Carglumic acid in hyperammonaemia due to organic acidurias: a profile of its use in the EU. DRUGS & THERAPY PERSPECTIVES 2019. [DOI: 10.1007/s40267-018-00595-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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10
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Kose E, Kuyum P, Aksoy B, Häberle J, Arslan N, Ozturk Y. First report of carglumic acid in a patient with citrullinemia type 1 (argininosuccinate synthetase deficiency). J Clin Pharm Ther 2017; 43:124-128. [PMID: 28741715 DOI: 10.1111/jcpt.12593] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 06/20/2017] [Indexed: 12/30/2022]
Abstract
WHAT IS KNOWN AND OBJECTIVE Carglumic acid is a structural analogue of human N-acetylglutamate, which has become an alternative therapeutic option for hyperammonaemia in organic acidaemias such as isovaleric acidaemia, methylmalonic acidaemia and propionic acidaemia, and it has been suggested in other urea cycle disorders such as ornithine transcarbamylase deficiency and carbamoyl phosphate synthetase 1 deficiency. CASE DESCRIPTION A male newborn was diagnosed with citrullinemia after serum amino acid analyses revealed markedly elevated citrulline concentration together with homozygous p.Gly390Arg mutation in ASS1 gene. The ammonia concentration decreased and blood gas analysis normalized after peritoneal dialysis was performed for three days. Also, sodium benzoate, L-arginine and parenteral nutrition with glucose and lipid therapy were initiated. Until 1 year of age, low adherence to sodium benzoate therapy due to unpleasant taste caused hyperammonaemic episodes and obligated us to initiate carglumic acid (100 mg/kg/day) therapy. During treatment with carglumic acid, the median ammonia level was 45.6 µmol/L. The patient's treatment was switched from carglumic acid to sodium phenylbutyrate when he was 4.5 years old. Currently, the patient is 6.5 years old and remains under follow-up with sodium phenylbutyrate, L-arginine and protein-restricted diet. Plasma ornithine level was found to be significantly lower during the carglumic acid treatment compared to other treatments (P=.039). Also, glutamic acid was found to be higher during the sodium benzoate treatment period compared to other treatment periods (P=.024). WHAT IS NEW AND CONCLUSION To the best of our knowledge, this is the first report describing the long-term use of carglumic acid in a patient with argininosuccinate synthetase deficiency.
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Affiliation(s)
- E Kose
- Division of Pediatric Metabolism and Nutrition, Dokuz Eylul University, Izmir, Turkey
| | - P Kuyum
- Division of Pediatric Gastroenterology, Dokuz Eylul University, Izmir, Turkey
| | - B Aksoy
- Division of Pediatric Gastroenterology, Dokuz Eylul University, Izmir, Turkey
| | - J Häberle
- Division of Metabolism and Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland
| | - N Arslan
- Division of Pediatric Metabolism and Nutrition, Dokuz Eylul University, Izmir, Turkey
| | - Y Ozturk
- Division of Pediatric Gastroenterology, Dokuz Eylul University, Izmir, Turkey
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11
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Shi D, Zhao G, Ah Mew N, Tuchman M. Precision medicine in rare disease: Mechanisms of disparate effects of N-carbamyl-l-glutamate on mutant CPS1 enzymes. Mol Genet Metab 2017; 120:198-206. [PMID: 28007335 PMCID: PMC5346444 DOI: 10.1016/j.ymgme.2016.12.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 12/05/2016] [Accepted: 12/05/2016] [Indexed: 02/07/2023]
Abstract
This study documents the disparate therapeutic effect of N-carbamyl-l-glutamate (NCG) in the activation of two different disease-causing mutants of carbamyl phosphate synthetase 1 (CPS1). We investigated the effects of NCG on purified recombinant wild-type (WT) mouse CPS1 and its human corresponding E1034G (increased ureagenesis on NCG) and M792I (decreased ureagenesis on NCG) mutants. NCG activates WT CPS1 sub-optimally compared to NAG. Similar to NAG, NCG, in combination with MgATP, stabilizes the enzyme, but competes with NAG binding to the enzyme. NCG supplementation activates available E1034G mutant CPS1 molecules not bound to NAG enhancing ureagenesis. Conversely, NCG competes with NAG binding to the scarce M792I mutant enzyme further decreasing residual ureagenesis. These results correlate with the respective patient's response to NCG. Particular caution should be taken in the administration of NCG to patients with hyperammonemia before their molecular bases of their urea cycle disorders is known.
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Affiliation(s)
- Dashuang Shi
- Center for Genetic Medicine Research, Department of Integrative Systems Biology, Children's Research Institute, Children's National Health System, The George Washington University, Washington, DC 20010, USA.
| | - Gengxiang Zhao
- Center for Genetic Medicine Research, Department of Integrative Systems Biology, Children's Research Institute, Children's National Health System, The George Washington University, Washington, DC 20010, USA
| | - Nicholas Ah Mew
- Center for Genetic Medicine Research, Department of Integrative Systems Biology, Children's Research Institute, Children's National Health System, The George Washington University, Washington, DC 20010, USA
| | - Mendel Tuchman
- Center for Genetic Medicine Research, Department of Integrative Systems Biology, Children's Research Institute, Children's National Health System, The George Washington University, Washington, DC 20010, USA
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12
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Chapel-Crespo CC, Diaz GA, Oishi K. Efficacy of N-carbamoyl-L-glutamic acid for the treatment of inherited metabolic disorders. Expert Rev Endocrinol Metab 2016; 11:467-473. [PMID: 30034506 PMCID: PMC6054484 DOI: 10.1080/17446651.2016.1239526] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
INTRODUCTION N-carbamoyl-L-glutamic acid (NCG) is a synthetic analogue of N-acetyl glutamate (NAG) that works effectively as a cofactor for carbamoyl phosphate synthase 1 and enhances ureagenesis by activating the urea cycle. NCG (brand name, Carbaglu) was recently approved by the United States Food and Drug Administration (US FDA) for the management of NAGS deficiency and by the European Medicines Agency (EMA) for the treatment of NAGS deficiency as well as for the treatment of hyperammonenia in propionic, methylmalonic and isovaleric acidemias in Europe. AREAS COVERED The history, mechanism of action, and efficacy of this new drug are described. Moreover, clinical utility of NCG in a variety of inborn errors of metabolism with secondary NAGS deficiency is discussed. EXPERT COMMENTARY NCG has favorable pharmacological features including better bioavailability compared to NAG. The clinical use of NCG has proven to be so effective as to make dietary protein restriction unnecessary for patients with NAGS deficiency. It has been also demonstrated to be effective for hyperammonemia secondary to other types of inborn errors of metabolism. NCG may have additional therapeutic potential in conditions such as hepatic hyperammonemic encephalopathy secondary to chemotherapies or other liver pathology.
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Affiliation(s)
- Cristel C Chapel-Crespo
- Department of Genetics and Genomic Sciences, Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - George A Diaz
- Department of Genetics and Genomic Sciences, Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Kimihiko Oishi
- Department of Genetics and Genomic Sciences, Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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13
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Burlina A, Cazzorla C, Zanonato E, Viggiano E, Fasan I, Polo G. Clinical experience with N-carbamylglutamate in a single-centre cohort of patients with propionic and methylmalonic aciduria. Mol Genet Metab Rep 2016; 8:34-40. [PMID: 27489777 PMCID: PMC4949587 DOI: 10.1016/j.ymgmr.2016.06.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 06/24/2016] [Indexed: 12/30/2022] Open
Abstract
Background The effect of long-term N-carbamylglutamate (NCG) treatment on the rate and severity of decompensations due to propionic aciduria (PA) and methylmalonic aciduria (MMA) is unknown. This paper presents clinical experience from a single-centre cohort of patients with PA and MMA who received continuous long-term treatment with NCG. Methods The effect of oral NCG treatment (initial dose: 50 mg/kg/day) was investigated in patients with PA or MMA who were experiencing frequent progressive episodes of metabolic decompensation, who had pathological levels of ammonia, and who were referred to the Division of Metabolic Diseases, University Hospital of Padova between August 2014 and December 2015. Clinical and biochemical data, including the number of metabolic decompensations, lactic acid, uric acid and plasma ammonia levels, protein intake and body weight, were collected before and after the initiation of NCG treatment. Results Eight patients with PA (n = 4) and MMA (n = 4) aged 2–20 years were treated with NCG (50 mg/kg/day) for 7–16 months. Metabolic decompensation episodes decreased in number and severity, with three of the patients having no episodes (pre-treatment: 24 episodes; post-treatment: 9 episodes). After NCG treatment, all episodes were treated at home and none required hospitalisation, lactic acid values were 1.3–2.1 mmol/L and uric acid values were 0.21–0.36 mmol/L. Significant reductions in blood ammonia levels after NCG initiation were observed in five patients, whereas levels were reduced or maintained in the normal range in the remainder. Over the treatment period, patients had an increase in natural protein intake of 20–50% and gained 0–6.5 kg in bodyweight. Conclusion These observations suggest that, in addition to short-term benefits for the acute treatment of hyperammonaemia, NCG may be effective and well tolerated as a long-term treatment in patients with severe PA and MMA, and that further prospective studies are warranted.
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Affiliation(s)
- Alberto Burlina
- Division of Inherited Metabolic Diseases, University Hospital of Padova, Padova, Italy
| | - Chiara Cazzorla
- Division of Inherited Metabolic Diseases, University Hospital of Padova, Padova, Italy
| | - Elisa Zanonato
- Division of Inherited Metabolic Diseases, University Hospital of Padova, Padova, Italy
| | - Emanuela Viggiano
- Division of Inherited Metabolic Diseases, University Hospital of Padova, Padova, Italy
| | - Ilaria Fasan
- Division of Inherited Metabolic Diseases, University Hospital of Padova, Padova, Italy
| | - Giulia Polo
- Division of Inherited Metabolic Diseases, University Hospital of Padova, Padova, Italy
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14
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Maillot F, Blasco H, Lioger B, Bigot A, Douillard C. [Diagnosis and treatment of urea cycle disorders in adult patients]. Rev Med Interne 2016; 37:680-684. [PMID: 27032484 DOI: 10.1016/j.revmed.2016.02.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 11/19/2015] [Accepted: 02/26/2016] [Indexed: 12/30/2022]
Abstract
Urea cycle disorders (UCDs) are inborn errors of metabolism in which the clinical picture is mostly due to ammonia intoxication. UCD onset may be observed at any age. Acute decompensations of UCDs include neuro-psychiatric symptoms such as headache, confusion, convulsions, ataxia, agitation or delirium, as well as digestive symptoms, namely nausea and vomiting along with abdominal pain. Acute decompensations may lead to an irreversible coma in the absence of specific therapy. The first step is to measure promptly ammonemia in such patients, and start appropriate therapy on an emergency basis.
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Affiliation(s)
- F Maillot
- Service de médecine interne, centre de compétences des maladies héréditaires du métabolisme, hôpital Bretonneau, CHRU de Tours, 2, boulevard Tonnellé, 37044 Tours cedex 9, France; Université François-Rabelais, Tours, France; Inserm U1069, Tours, France.
| | - H Blasco
- Université François-Rabelais, Tours, France; Service de biochimie, CHRU de Tours, Tours, France; Inserm U930, Tours, France
| | - B Lioger
- Service de médecine interne, centre de compétences des maladies héréditaires du métabolisme, hôpital Bretonneau, CHRU de Tours, 2, boulevard Tonnellé, 37044 Tours cedex 9, France; Université François-Rabelais, Tours, France
| | - A Bigot
- Service de médecine interne, centre de compétences des maladies héréditaires du métabolisme, hôpital Bretonneau, CHRU de Tours, 2, boulevard Tonnellé, 37044 Tours cedex 9, France; Université François-Rabelais, Tours, France
| | - C Douillard
- Centre de référence des maladies héréditaires du métabolisme, CHRU de Lille, Lille, France
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15
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Richter M, Fairhall EA, Hoffmann SA, Tröbs S, Knöspel F, Probert PME, Oakley F, Stroux A, Wright MC, Zeilinger K. Pancreatic progenitor-derived hepatocytes are viable and functional in a 3D high density bioreactor culture system. Toxicol Res (Camb) 2016; 5:278-290. [PMID: 30090344 PMCID: PMC6062372 DOI: 10.1039/c5tx00187k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 11/12/2015] [Indexed: 01/15/2023] Open
Abstract
The rat pancreatic progenitor cell line B-13 is of interest for research on drug metabolism and toxicity since the cells trans-differentiate into functional hepatocyte-like cells (B-13/H) when treated with glucocorticoids. In this study we investigated the trans-differentiation and liver-specific functions of B-13/H cells in a three-dimensional (3D) multi-compartment bioreactor, which has already been successfully used for primary liver cell culture. Undifferentiated B-13 cells were inoculated into the bioreactor system and exposed to dexamethasone to promote hepatic trans-differentiation (B-13/HT). In a second approach, pre-differentiated B-13 cells were cultured in bioreactors for 15 days to evaluate the maintenance of liver-typical functions (B-13/HP). During trans-differentiation of B-13 cells into hepatocyte-like cells in the 3D bioreactor system (approach B-13/HT), an increase in glucose metabolism and in liver-specific functions (urea and albumin synthesis; cytochrome P450 [CYP] enzyme activity) was observed, whereas amylase - characteristic for exocrine pancreas and undifferentiated B-13 cells - decreased over time. In bioreactors with pre-differentiated cells (approach B-13/HP), the above liver-specific functions were maintained over the whole culture period. Results were confirmed by gene expression and protein analysis showing increased expression of carbamoyl-phosphate synthase 1 (CPS-1), albumin, CYP2E1, CYP2C11 and CYP3A1 with simultaneous loss of amylase. Immunohistochemical studies showed the formation of 3D structures with expression of liver-specific markers, including albumin, cytokeratin (CK) 18, CCAAT/enhancer-binding protein beta (CEBP-β), CYP2E1 and multidrug resistance protein 2 (MRP2). In conclusion, successful culture and trans-differentiation of B-13 cells in the 3D bioreactor was demonstrated. The requirement for only one hormone and simple culture conditions to generate liver-like cells makes this cell type useful for in vitro research using 3D high-density culture systems.
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Affiliation(s)
- M Richter
- Berlin-Brandenburg Center for Regenerative Therapies (BCRT) , Charité-Universitätsmedizin Berlin , Berlin , Germany .
| | - E A Fairhall
- Newcastle University , Institute Cellular Medicine , Newcastle Upon Tyne , UK
| | - S A Hoffmann
- Berlin-Brandenburg Center for Regenerative Therapies (BCRT) , Charité-Universitätsmedizin Berlin , Berlin , Germany .
| | - S Tröbs
- Berlin-Brandenburg Center for Regenerative Therapies (BCRT) , Charité-Universitätsmedizin Berlin , Berlin , Germany .
| | - F Knöspel
- Berlin-Brandenburg Center for Regenerative Therapies (BCRT) , Charité-Universitätsmedizin Berlin , Berlin , Germany .
| | - P M E Probert
- Newcastle University , Institute Cellular Medicine , Newcastle Upon Tyne , UK
| | - F Oakley
- Newcastle University , Institute Cellular Medicine , Newcastle Upon Tyne , UK
| | - A Stroux
- Institute for Biometry and Clinical Epidemiology , Charité-Universitätsmedizin Berlin , Berlin , Germany
| | - M C Wright
- Newcastle University , Institute Cellular Medicine , Newcastle Upon Tyne , UK
| | - K Zeilinger
- Berlin-Brandenburg Center for Regenerative Therapies (BCRT) , Charité-Universitätsmedizin Berlin , Berlin , Germany .
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16
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Sharma P, Shah PA, Sanyal M, Shrivastav PS. Challenges in optimizing sample preparation and LC-MS/MS conditions for the analysis of carglumic acid, an N-acetyl glutamate derivative in human plasma. Drug Test Anal 2015; 7:763-72. [PMID: 25677217 DOI: 10.1002/dta.1774] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Revised: 12/24/2014] [Accepted: 12/26/2014] [Indexed: 11/10/2022]
Abstract
This paper describes a systematic approach to overcoming challenges in developing a robust and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for reliable and precise determination of carglumic acid in human plasma. Sample extraction was tested on several reversed-phase solid-phase extraction (SPE) sorbents with different chemistries, such as hydrophobic C18, hydrophilic-lipophilic balance, and mixed-mode cation and anion exchange. The best recovery under the optimized extraction conditions was obtained with Oasis MAX (30 mg, 1cc) mixed-mode anion exchange (~ 50%) cartridge, compared to other sorbents from 100 μL plasma sample. Complete analytical separation of carglumic acid and carglumic acid-13C5 15N as an internal standard (IS) from endogenous plasma components was achieved on ACE 5CN (150 × 4.6 mm, 5 µm) column under isocratic conditions using acetonitrile:methanol (50:50, v/v) - 0.1% acetic acid in water [80:20, v/v] as the mobile phase. The deprotonated precursor → product ion transitions for carglumic acid (189/146) and IS (195/152) were monitored in the negative ionization mode on a triple quadrupole mass spectrometer. The regression curves were linear over a concentration range of 6.00-6000 ng/mL (r(2) ≥ 0.9987). Matrix effect was evaluated in terms of IS-normalized matrix factors, which ranged from 0.95 to 1.01 across four quality control levels. Intra- and inter-batch accuracy and precision, and the stability of carglumic acid in spiked plasma samples were assessed under different conditions. The method was applied to assess the pharmacokinetics of 100 mg/kg body weight carglumic acid in a healthy Indian subject.
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Affiliation(s)
- Primal Sharma
- Department of Chemistry, School of Sciences, Gujarat University, Ahmedabad, 380009, India
| | - Priyanka A Shah
- Department of Chemistry, School of Sciences, Gujarat University, Ahmedabad, 380009, India
| | - Mallika Sanyal
- Chemistry Department, St Xavier's College, Navrangpura, Ahmedabad, 380009, India
| | - Pranav S Shrivastav
- Department of Chemistry, School of Sciences, Gujarat University, Ahmedabad, 380009, India
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17
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Hu C, Tai DS, Park H, Cantero-Nieto G, Chan E, Yudkoff M, Cederbaum SD, Lipshutz GS. Minimal ureagenesis is necessary for survival in the murine model of hyperargininemia treated by AAV-based gene therapy. Gene Ther 2015; 22:111-5. [PMID: 25474440 PMCID: PMC4320015 DOI: 10.1038/gt.2014.106] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 09/15/2014] [Accepted: 10/27/2014] [Indexed: 02/07/2023]
Abstract
Hyperammonemia is less severe in arginase 1 deficiency compared with other urea cycle defects. Affected patients manifest hyperargininemia and infrequent episodes of hyperammonemia. Patients typically suffer from neurological impairment with cortical and pyramidal tract deterioration, spasticity, loss of ambulation, seizures and intellectual disability; death is less common than with other urea cycle disorders. In a mouse model of arginase I deficiency, the onset of symptoms begins with weight loss and gait instability, which progresses toward development of tail tremor with seizure-like activity; death typically occurs at about 2 weeks of life. Adeno-associated viral vector gene replacement strategies result in long-term survival of mice with this disorder. With neonatal administration of vector, the viral copy number in the liver greatly declines with hepatocyte proliferation in the first 5 weeks of life. Although the animals do survive, it is not known from a functional standpoint how well the urea cycle is functioning in the adult animals that receive adeno-associated virus. In these studies, we administered [1-13C] acetate to both littermate controls and adeno-associated virus-treated arginase 1 knockout animals and examined flux through the urea cycle. Circulating ammonia levels were mildly elevated in treated animals. Arginine and glutamine also had perturbations. Assessment 30 min after acetate administration demonstrated that ureagenesis was present in the treated knockout liver at levels as low at 3.3% of control animals. These studies demonstrate that only minimal levels of hepatic arginase activity are necessary for survival and ureagenesis in arginase-deficient mice and that this level of activity results in control of circulating ammonia. These results may have implications for potential therapy in humans with arginase deficiency.
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Affiliation(s)
- Chuhong Hu
- Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Denise S. Tai
- Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Hana Park
- Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Gloria Cantero-Nieto
- Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Emily Chan
- Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Marc Yudkoff
- Division of Metabolic Disease, Department of Pediatrics, Children’s Hospital of Philadelphia
| | - Stephen D. Cederbaum
- Department of Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, California
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, California
- Department of Psychiatry, David Geffen School of Medicine at UCLA, Los Angeles, California
- Department of Intellectual and Developmental Disabilities Research Center at UCLA, David Geffen School of Medicine at UCLA, Los Angeles, California
- The Semel Institute for Neuroscience, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Gerald S. Lipshutz
- Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, California
- Department of Psychiatry, David Geffen School of Medicine at UCLA, Los Angeles, California
- Department of Intellectual and Developmental Disabilities Research Center at UCLA, David Geffen School of Medicine at UCLA, Los Angeles, California
- The Semel Institute for Neuroscience, David Geffen School of Medicine at UCLA, Los Angeles, California
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California
- Department of Urology, David Geffen School of Medicine at UCLA, Los Angeles, California
- Broad Center of Regenerative Medicine and Stem Cell Research, David Geffen School of Medicine at UCLA, Los Angeles, California
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18
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Ah Mew N, McCarter R, Daikhin Y, Lichter U, Nissim I, Yudkoff M, Tuchman AM. Augmenting ureagenesis in patients with partial carbamyl phosphate synthetase 1 deficiency with N-carbamyl-L-glutamate. J Pediatr 2014; 165:401-403.e3. [PMID: 24880889 PMCID: PMC4111993 DOI: 10.1016/j.jpeds.2014.04.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 03/05/2014] [Accepted: 04/07/2014] [Indexed: 11/30/2022]
Abstract
Identical studies using stable isotopes were performed before and after a 3-day trial of oral N-carbamyl-l-glutamate (NCG) in 5 subjects with late-onset carbamyl phosphate synthetase deficiency. NCG augmented ureagenesis and decreased plasma ammonia in 4 of 5 subjects. There was marked improvement in nitrogen metabolism with long-term NCG administration in 1 subject.
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Affiliation(s)
- Nicholas Ah Mew
- Center for Translational Sciences, Children's National Health System, The George Washington University, Washington, DC 20010, USA, Division of Genetics and Metabolism, Children's National Health System, The George Washington University, Washington, DC 20010, USA,Corresponding author: Nicholas Ah Mew Division of Genetics and Metabolism Children's National Health System 111 Michigan Avenue, NW Washington, DC 20010, USA Telephone: (202) 476-5863 Fax: (202) 476-5650
| | - Robert McCarter
- Center for Translational Sciences, Children's National Health System, The George Washington University, Washington, DC 20010, USA
| | - Yevgeny Daikhin
- Department of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Uta Lichter
- Center for Translational Sciences, Children's National Health System, The George Washington University, Washington, DC 20010, USA, Division of Genetics and Metabolism, Children's National Health System, The George Washington University, Washington, DC 20010, USA
| | - Ilana Nissim
- Department of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Marc Yudkoff
- Department of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - and Mendel Tuchman
- Center for Genetic Medicine Research, Children's National Health System, The George Washington University, Washington, DC 20010, USA
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19
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Zhao G, Jin Z, Allewell NM, Tuchman M, Shi D. Crystal structure of the N-acetyltransferase domain of human N-acetyl-L-glutamate synthase in complex with N-acetyl-L-glutamate provides insights into its catalytic and regulatory mechanisms. PLoS One 2013; 8:e70369. [PMID: 23894642 PMCID: PMC3722096 DOI: 10.1371/journal.pone.0070369] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 06/17/2013] [Indexed: 11/23/2022] Open
Abstract
N-acetylglutamate synthase (NAGS) catalyzes the conversion of AcCoA and L-glutamate to CoA and N-acetyl-L-glutamate (NAG), an obligate cofactor for carbamyl phosphate synthetase I (CPSI) in the urea cycle. NAGS deficiency results in elevated levels of plasma ammonia which is neurotoxic. We report herein the first crystal structure of human NAGS, that of the catalytic N-acetyltransferase (hNAT) domain with N-acetyl-L-glutamate bound at 2.1 Å resolution. Functional studies indicate that the hNAT domain retains catalytic activity in the absence of the amino acid kinase (AAK) domain. Instead, the major functions of the AAK domain appear to be providing a binding site for the allosteric activator, L-arginine, and an N-terminal proline-rich motif that is likely to function in signal transduction to CPS1. Crystalline hNAT forms a dimer similar to the NAT-NAT dimers that form in crystals of bifunctional N-acetylglutamate synthase/kinase (NAGS/K) from Maricaulis maris and also exists as a dimer in solution. The structure of the NAG binding site, in combination with mutagenesis studies, provide insights into the catalytic mechanism. We also show that native NAGS from human and mouse exists in tetrameric form, similar to those of bifunctional NAGS/K.
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Affiliation(s)
- Gengxiang Zhao
- Center for Genetic Medicine Research and Department of Integrative Systems Biology, Children’s National Medical Center, The George Washington University, Washington, D. C., United States of America
| | - Zhongmin Jin
- Southeast Regional Collaborative Access Team, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, United States of America
| | - Norma M. Allewell
- Department of Cell Biology and Molecular Genetics and Department of Chemistry and Biochemistry, College of Computer, Mathematical, and Natural Sciences, University of Maryland, College Park, Maryland, United States of America
| | - Mendel Tuchman
- Center for Genetic Medicine Research and Department of Integrative Systems Biology, Children’s National Medical Center, The George Washington University, Washington, D. C., United States of America
| | - Dashuang Shi
- Center for Genetic Medicine Research and Department of Integrative Systems Biology, Children’s National Medical Center, The George Washington University, Washington, D. C., United States of America
- * E-mail:
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Successful early management of a female patient with a metabolic stroke due to ornithine transcarbamylase deficiency. Pediatr Emerg Care 2013; 29:656-8. [PMID: 23640148 DOI: 10.1097/pec.0b013e31828ec2b9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
BACKGROUND Ornithine transcarbamylase deficiency (OTC-D) is a urea cycle disorder caused by dysfunction of ornithine transcarbamylase, which frequently leads to hyperammonemia. Hyperammonemia represents a medical emergency requiring prompt treatment to reduce plasma ammonia levels and prevent severe neurological damage, coma, and death, particularly in patients with acute decompensation-related coma. The clinical symptoms of OTC-D can manifest themselves either at an early stage, which is often associated with severe symptoms, or in later life (late-onset OTC-D), when symptoms may be less severe. There is currently little agreement over diagnostic signs of the condition or the most appropriate therapeutic approach. Hyperammonemia is usually treated with ammonia scavengers, continuous venovenous hemodialysis, and dietary changes. N-carbamylglutamate is approved for the treatment of hyperammonemia in N-acetylglutamate synthetase deficiency and may have efficacy in other urea cycle disorders. METHODS/RESULTS Here, we report a 13-year-old girl who was diagnosed with OTC-D at the age of 3 years. On this occasion, the patient presented with vomiting, lethargy, and mental confusion. Despite biochemical parameters being within normal ranges, she was comatose within a few hours. She was promptly treated with a combined therapy of continuous venovenous hemodialysis and N-carbamylglutamate, resulting in a gradual normalization of clinical symptoms within 30 hours. No neurological damage was apparent at 18 months after treatment. CONCLUSIONS This case demonstrates that clinical benefits can be obtained by beginning aggressive treatment of OTC-D within a few hours of the onset of severe neurological symptoms even in the absence of altered biochemical markers.
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Abstract
N-acetyl-glutamate synthase (NAGS) deficiency is a rare autosomal recessive urea cycle disorder (UCD) that uncommonly presents in adulthood. Adult presentations of UCDs include; confusional episodes, neuropsychiatric symptoms and encephalopathy. To date, there have been no detailed neurological descriptions of an adult onset presentation of NAGS deficiency. In this review we examine the clinical presentation and management of UCDs with an emphasis on NAGS deficiency. An illustrative case is provided. Plasma ammonia levels should be measured in all adult patients with unexplained encephalopathy, as treatment can be potentially life-saving. Availability of N-carbamylglutamate (NCG; carglumic acid) has made protein restriction largely unnecessary in treatment regimens currently employed. Genetic counselling remains an essential component of management of NAGS.
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Häberle J. Carglumic acid for the treatment of N-acetylglutamate synthase deficiency and acute hyperammonemia. Expert Rev Endocrinol Metab 2012; 7:263-271. [PMID: 30780843 DOI: 10.1586/eem.12.17] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Carglumic acid is a structural analog and the first registered synthetic form of the naturally occurring allosteric activator of the urea cycle, N-acetylglutamate (NAG), which is the product of the enzyme NAG synthase (NAGS). Because NAG is essential for the function of carbamoylphosphate synthetase 1 as the first step of the urea cycle, a decreased availability of NAG due to primary or secondary defects of NAGS will affect ammonia detoxification in the urea cycle. Carglumic acid (Carbaglu®, Orphan Europe SARL, Paris, France) is approved for the acute and long-term treatment of primary defects of NAGS in Europe and the USA. In addition, it is approved in Europe for the treatment of acute hyperammonemia in patients with specific organic acidurias that can lead to NAG deficiency secondary to inhibition of NAGS. This article reviews the use of carglumic acid for both approved indications and considers the potential of this compound for acute hyperammonemias in general.
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Affiliation(s)
- Johannes Häberle
- a University Children's Hospital, Division of Metabolism, Children's Research Center, Steinwiesstrasse 75, CH-8032 Zürich, Switzerland.
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Heibel SK, Ah Mew N, Caldovic L, Daikhin Y, Yudkoff M, Tuchman M. N-carbamylglutamate enhancement of ureagenesis leads to discovery of a novel deleterious mutation in a newly defined enhancer of the NAGS gene and to effective therapy. Hum Mutat 2011; 32:1153-60. [PMID: 21681857 DOI: 10.1002/humu.21553] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Accepted: 06/01/2011] [Indexed: 11/09/2022]
Abstract
N-acetylglutamate synthase (NAGS) catalyzes the conversion of glutamate and acetyl-CoA to NAG, the essential allosteric activator of carbamyl phosphate synthetase I, the first urea cycle enzyme in mammals. A 17-year-old female with recurrent hyperammonemia attacks, the cause of which remained undiagnosed for 8 years in spite of multiple molecular and biochemical investigations, showed markedly enhanced ureagenesis (measured by isotope incorporation) in response to N-carbamylglutamate (NCG). This led to sequencing of the regulatory regions of the NAGS gene and identification of a deleterious single-base substitution in the upstream enhancer. The homozygous mutation (c.-3064C>A), affecting a highly conserved nucleotide within the hepatic nuclear factor 1 (HNF-1) binding site, was not found in single nucleotide polymorphism databases and in a screen of 1,086 alleles from a diverse population. Functional assays demonstrated that this mutation decreases transcription and binding of HNF-1 to the NAGS gene, while a consensus HNF-1 binding sequence enhances binding to HNF-1 and increases transcription. Oral daily NCG therapy restored ureagenesis in this patient, normalizing her biochemical markers, and allowing discontinuation of alternate pathway therapy and normalization of her diet with no recurrence of hyperammonemia. Inc.
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Affiliation(s)
- Sandra K Heibel
- Research Center for Genetic Medicine, Children's National Medical Center, The George Washington University, Washington, DC, USA
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Häberle J. Role of carglumic acid in the treatment of acute hyperammonemia due to N-acetylglutamate synthase deficiency. Ther Clin Risk Manag 2011; 7:327-32. [PMID: 21941437 PMCID: PMC3176164 DOI: 10.2147/tcrm.s12703] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
N-acetylglutamate synthase (NAGS) deficiency is a rare inborn error of metabolism affecting ammonia detoxification in the urea cycle. The product of NAGS is N-acetylglutamate which is the absolutely required allosteric activator of the first urea cycle enzyme carbamoylphosphate synthetase 1. In defects of NAGS, the urea cycle function can be severely affected resulting in fatal hyperammonemia in neonatal patients or at any later stage in life. NAGS deficiency can be treated with a structural analog of N-acetylglutamate, N-carbamyl-L-glutamate, which is available for enteral use as a licensed drug. Since NAGS deficiency is an extremely rare disorder, reports on the use of N-carbamyl-L-glutamate are mainly based on single patients. According to these, the drug is very effective in treating acute hyperammonemia by avoiding the need for detoxification during the acute metabolic decompensation. Also during long-term treatment, N-carbamyl-L-glutamate is effective in maintaining normal plasma ammonia levels and avoiding the need for additional drug therapy or protein-restricted diet. Open questions remain which concern the optimal dosage in acute and long-term use of N-carbamyl-L-glutamate and potential additional disorders in which the drug might also be effective in treating acute hyperammonemia. This review focuses on the role of N-carbamyl-L-glutamate for the treatment of acute hyperammonemia due to primary NAGS deficiency but will briefly discuss the current knowledge on the role of N-carbamyl-L-glutamate for treatment of secondary NAGS deficiencies.
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Affiliation(s)
- Johannes Häberle
- Kinderspital Zürich, Abteilung Stoffwechsel, Zürich, Switzerland
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Nissim I, Horyn O, Nissim I, Daikhin Y, Caldovic L, Barcelona B, Cervera J, Tuchman M, Yudkoff M. Down-regulation of hepatic urea synthesis by oxypurines: xanthine and uric acid inhibit N-acetylglutamate synthase. J Biol Chem 2011; 286:22055-68. [PMID: 21540182 DOI: 10.1074/jbc.m110.209023] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We previously reported that isobutylmethylxanthine (IBMX), a derivative of oxypurine, inhibits citrulline synthesis by an as yet unknown mechanism. Here, we demonstrate that IBMX and other oxypurines containing a 2,6-dione group interfere with the binding of glutamate to the active site of N-acetylglutamate synthetase (NAGS), thereby decreasing synthesis of N-acetylglutamate, the obligatory activator of carbamoyl phosphate synthase-1 (CPS1). The result is reduction of citrulline and urea synthesis. Experiments were performed with (15)N-labeled substrates, purified hepatic CPS1, and recombinant mouse NAGS as well as isolated mitochondria. We also used isolated hepatocytes to examine the action of various oxypurines on ureagenesis and to assess the ameliorating affect of N-carbamylglutamate and/or l-arginine on NAGS inhibition. Among various oxypurines tested, only IBMX, xanthine, or uric acid significantly increased the apparent K(m) for glutamate and decreased velocity of NAGS, with little effect on CPS1. The inhibition of NAGS is time- and dose-dependent and leads to decreased formation of the CPS1-N-acetylglutamate complex and consequent inhibition of citrulline and urea synthesis. However, such inhibition was reversed by supplementation with N-carbamylglutamate. The data demonstrate that xanthine and uric acid, both physiologically occurring oxypurines, inhibit the hepatic synthesis of N-acetylglutamate. An important and novel concept emerging from this study is that xanthine and/or uric acid may have a role in the regulation of ureagenesis and, thus, nitrogen homeostasis in normal and disease states.
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Affiliation(s)
- Itzhak Nissim
- Division of Child Development, Rehabilitation Medicine, and Metabolic Disease, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA.
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Daniotti M, la Marca G, Fiorini P, Filippi L. New developments in the treatment of hyperammonemia: emerging use of carglumic acid. Int J Gen Med 2011; 4:21-8. [PMID: 21403788 PMCID: PMC3056327 DOI: 10.2147/ijgm.s10490] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Hyperammonemia is a true neonatal emergency with high toxicity for the central nervous system and developmental delay. The causes of neonatal hyperammonemia are genetic defects of urea cycle enzymes, organic acidemias, lysinuric protein intolerance, hyperammonemia-hyperornithinemia- homocitrullinemia syndrome, transient hyperammonemia of the newborn, and congenital hyperinsulinism with hyperammonemia. In some of these conditions the high blood ammonia levels are due to the reduction of N-acetylglutamate, an essential cofactor necessary for the function of the urea cycle, or to the reduction of carbamoyl-phosphate synthase-I activity. In these cases, N-carbamylglutamate (carglumic acid) can be administered together with the conventional therapy. Carglumic acid is an analog of N-acetylglutamate that has a direct action on carbamoyl-phosphate synthase-I. Its effects are reactivation of the urea cycle and reduction of plasma ammonia levels. As a consequence it improves the traditional treatment, avoiding the need of hemodialysis and peritoneal dialysis. In this review we evaluate the possible field of application of carglumic acid and its effectiveness and safety.
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Affiliation(s)
- Marta Daniotti
- Neonatal Intensive Care Unit, Department of Perinatal Medicine, “A. Meyer” University Children’s Hospital, Florence, Italy
| | - Giancarlo la Marca
- Mass Spectrometry, Clinical Chemistry and Pharmacology Laboratory, Neuroscience Department, “A. Meyer” University Children’s Hospital, Florence, Italy
| | - Patrizio Fiorini
- Neonatal Intensive Care Unit, Department of Perinatal Medicine, “A. Meyer” University Children’s Hospital, Florence, Italy
| | - Luca Filippi
- Neonatal Intensive Care Unit, Department of Perinatal Medicine, “A. Meyer” University Children’s Hospital, Florence, Italy
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Mew NA, McCarter R, Daikhin Y, Nissim I, Yudkoff M, Tuchman M. N-carbamylglutamate augments ureagenesis and reduces ammonia and glutamine in propionic acidemia. Pediatrics 2010; 126:e208-14. [PMID: 20566609 PMCID: PMC3297024 DOI: 10.1542/peds.2010-0008] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVES The objective of this study was to determine whether N-carbamylglutamate (NCG) reduces plasma levels of ammonia and glutamine and increases the rate of ureagenesis in patients with propionic acidemia (PA). METHODS Identical 4-hour studies were performed before and immediately after a 3-day trial of oral NCG in 7 patients with PA. An oral bolus of [(13)C]sodium acetate was administered at the start of each study, and sequential blood samples were obtained to measure [(13)C]urea, ammonia, urea, and amino acids. RESULTS With longitudinal mixed-effects linear regression, peak [(13)C]urea increased after treatment with NCG (from 2.2 to 3.8 microM; P < .0005). There were concomitant decreases in mean plasma ammonia (59-43 microM; P < .018) and glutamine (552-331 microM; P < .0005). CONCLUSIONS NCG augments ureagenesis and decreases plasma ammonia and glutamine in patients with PA. The drug may serve as an important therapeutic adjunct in the treatment of acute hyperammonemia in this disorder.
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Affiliation(s)
- Nicholas Ah Mew
- Research Center for Genetic Medicine, Children’s National Medical Center, The George Washington University, Washington, DC 20010, USA
| | - Robert McCarter
- Research Center for Genetic Medicine, Children’s National Medical Center, The George Washington University, Washington, DC 20010, USA
| | - Yevgeny Daikhin
- Children’s Hospital of Philadelphia, Dept. of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Itzhak Nissim
- Children’s Hospital of Philadelphia, Dept. of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Marc Yudkoff
- Children’s Hospital of Philadelphia, Dept. of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Mendel Tuchman
- Research Center for Genetic Medicine, Children’s National Medical Center, The George Washington University, Washington, DC 20010, USA
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Yudkoff M, Ah Mew N, Daikhin Y, Horyn O, Nissim I, Nissim I, Payan I, Tuchman M. Measuring in vivo ureagenesis with stable isotopes. Mol Genet Metab 2010; 100 Suppl 1:S37-41. [PMID: 20338795 PMCID: PMC2858793 DOI: 10.1016/j.ymgme.2010.02.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2010] [Accepted: 02/21/2010] [Indexed: 11/16/2022]
Abstract
Stable isotopes have been an invaluable adjunct to biomedical research for more than 70years. Indeed, the isotopic approach has revolutionized our understanding of metabolism, revealing it to be an intensely dynamic process characterized by an unending cycle of synthesis and degradation. Isotopic studies have taught us that the urea cycle is intrinsic to such dynamism, since it affords a capacious mechanism by which to eliminate waste nitrogen when rates of protein degradation (or dietary protein intake) are especially high. Isotopes have enabled an appreciation of the degree to which ureagenesis is compromised in patients with urea cycle defects. Indeed, isotopic studies of urea cycle flux correlate well with the severity of cognitive impairment in these patients. Finally, the use of isotopes affords an ideal tool with which to gauge the efficacy of therapeutic interventions to augment residual flux through the cycle.
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Affiliation(s)
- Marc Yudkoff
- Children's Hospital of Philadelphia, Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
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Caldovic L, Mew NA, Shi D, Morizono H, Yudkoff M, Tuchman M. N-acetylglutamate synthase: structure, function and defects. Mol Genet Metab 2010; 100 Suppl 1:S13-9. [PMID: 20303810 PMCID: PMC2876818 DOI: 10.1016/j.ymgme.2010.02.018] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Accepted: 02/22/2010] [Indexed: 11/26/2022]
Abstract
N-acetylglutamate (NAG) is a unique enzyme cofactor, essential for liver ureagenesis in mammals while it is the first committed substrate for de novo arginine biosynthesis in microorganisms and plants. The enzyme that produces NAG from glutamate and CoA, NAG synthase (NAGS), is allosterically inhibited by arginine in microorganisms and plants and activated in mammals. This transition of the allosteric effect occurred when tetrapods moved from sea to land. The first mammalian NAGS gene (from mouse) was cloned in 2002 and revealed significant differences from the NAGS ortholog in microorganisms. Almost all NAGS genes possess a C-terminus transferase domain in which the catalytic activity resides and an N-terminus kinase domain where arginine binds. The three-dimensional structure of NAGS shows two distinctly folded domains. The kinase domain binds arginine while the acetyltransferase domain contains the catalytic site. NAGS deficiency in humans leads to hyperammonemia and can be primary, due to mutations in the NAGS gene or secondary due to other mitochondrial aberrations that interfere with the normal function of the same enzyme. For either condition, N-carbamylglutamate (NCG), a stable functional analog of NAG, was found to either restore or improve the deficient urea-cycle function.
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Affiliation(s)
- Ljubica Caldovic
- Children’s Research Institute, Children’s National Medical Center, 111 Michigan Ave NW, The George Washington University, Washington, DC, 20010, USA
| | - Nicholas Ah Mew
- Children’s Research Institute, Children’s National Medical Center, 111 Michigan Ave NW, The George Washington University, Washington, DC, 20010, USA
| | - Dashuang Shi
- Children’s Research Institute, Children’s National Medical Center, 111 Michigan Ave NW, The George Washington University, Washington, DC, 20010, USA
| | - Hiroki Morizono
- Children’s Research Institute, Children’s National Medical Center, 111 Michigan Ave NW, The George Washington University, Washington, DC, 20010, USA
| | - Marc Yudkoff
- Children’s Hospital of Philadelphia, 34th Street and Civic Center Blvd, Philadelphia, PA, 19104; Dept. of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, PA, 19104, USA
| | - Mendel Tuchman
- Children’s Research Institute, Children’s National Medical Center, 111 Michigan Ave NW, The George Washington University, Washington, DC, 20010, USA
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