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Kaczmarczyk A, Baker M, Diddle J, Yuzyuk T, Valle D, Lindstrom K. A neonate with ornithine aminotransferase deficiency; insights on the hyperammonemia-associated biochemical phenotype of gyrate atrophy. Mol Genet Metab Rep 2022; 31:100857. [PMID: 35782604 PMCID: PMC9248225 DOI: 10.1016/j.ymgmr.2022.100857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 02/26/2022] [Accepted: 02/27/2022] [Indexed: 11/29/2022] Open
Affiliation(s)
- Aneta Kaczmarczyk
- Department of Pathology, University of Utah, Salt Lake City, UT, USA
- ARUP Institute for Clinical and Experimental Pathology®, Salt Lake City, UT, USA
- Corresponding author at: ARUP Laboratories, 500 Chipeta Way, MS115, Salt Lake City, UT 84108, USA.
| | - Mark Baker
- Phoenix Children's Pediatric Residency Program Alliance, Phoenix Children's Hospital, Phoenix, AZ, USA
| | - Julianna Diddle
- Phoenix Children's Pediatric Residency Program Alliance, Phoenix Children's Hospital, Phoenix, AZ, USA
| | - Tatiana Yuzyuk
- Department of Pathology, University of Utah, Salt Lake City, UT, USA
- ARUP Institute for Clinical and Experimental Pathology®, Salt Lake City, UT, USA
| | - David Valle
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Kristin Lindstrom
- Division of Genetics and Metabolism, Phoenix Children's Hospital, Phoenix, AZ, USA
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Low Tissue Creatine: A Therapeutic Target in Clinical Nutrition. Nutrients 2022; 14:nu14061230. [PMID: 35334887 PMCID: PMC8955088 DOI: 10.3390/nu14061230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/07/2022] [Accepted: 03/08/2022] [Indexed: 11/25/2022] Open
Abstract
Low tissue creatine characterizes many conditions, including neurodegenerative, cardiopulmonary, and metabolic diseases, with a magnitude of creatine shortfall often corresponds well to a disorder’s severity. A non-invasive monitoring of tissue metabolism with magnetic resonance spectroscopy (MRS) might be a feasible tool to evaluate suboptimal levels of creatine for both predictive, diagnostic, and therapeutic purposes. This mini review paper summarizes disorders with deficient creatine levels and provides arguments for assessing and employing tissue creatine as a relevant target in clinical nutrition.
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Abstract
Gyrate atrophy (GA) of the choroid and retina is a rare autosomal recessive genetic condition characterized by elevation of the plasma level of the amino acid ornithine due to deficiency of the enzyme ornithine ketoacid aminotransferase. Accumulation of ornithine occurs in various body tissues but leads primarily to characteristic ophthalmic manifestations including myopia, cataract, progressive chorioretinal atrophy, and macular changes. Patients usually present with night blindness that starts in the first decade of life followed by visual field constriction and eventually diminution of the central visual acuity and blindness. The condition has been reported worldwide and its differential diagnosis is broad and includes choroideremia and retinitis pigmentosa. Treatment currently depends on life-long dietary modifications including restriction of the amino acid arginine in diet. This article describes in detail the pathogenesis, clinical features, multimodal imaging findings, and treatment options for GA of the choroid and retina and its complications.
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Affiliation(s)
- Ayman G Elnahry
- Department of Ophthalmology, Faculty of Medicine, 63526Cairo University, Cairo, Egypt
| | - Gehad A Elnahry
- Department of Ophthalmology, Faculty of Medicine, 63526Cairo University, Cairo, Egypt
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Ingoglia F, Chong JL, Pasquali M, Longo N. Creatine metabolism in patients with urea cycle disorders. Mol Genet Metab Rep 2021; 29:100791. [PMID: 34471603 PMCID: PMC8387902 DOI: 10.1016/j.ymgmr.2021.100791] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 08/13/2021] [Indexed: 12/31/2022] Open
Abstract
The urea cycle generates arginine that is one of the major precursors for creatine biosynthesis. Here we evaluate levels of creatine and guanidinoacetate (the precursor in the synthesis of creatine) in plasma samples (ns = 207) of patients (np = 73) with different types of urea cycle disorders (ornithine transcarbamylase deficiency (ns = 22; np = 7), citrullinemia type 1 (ns = 60; np = 22), argininosuccinic aciduria (ns = 81; np = 31), arginase deficiency (ns = 44; np = 13)). The concentration of plasma guanidinoacetate positively correlated (p < 0.001, R2 = 0.64) with levels of arginine, but not with glycine in all patients with urea cycle defects, rising to levels above normal in most samples (34 out of 44) of patients with arginase deficiency. In contrast to patients with guanidinoacetate methyltransferase deficiency (a disorder of creatine synthesis characterized by elevated guanidinoacetate concentrations), creatine levels were normal (32 out of 44) or above normal (12 out of 44) in samples from patients with arginase deficiency. Creatine levels correlated significantly, but poorly (p < 0.01, R2 = 0.1) with guanidinoacetate levels and, despite being overall in the normal range in patients with all other urea cycle disorders, were occasionally below normal in some patients with argininosuccinic acid synthase and lyase deficiency. Creatine levels positively correlated with levels of methionine (p < 0.001, R2 = 0.16), the donor of the methyl group for creatine synthesis. The direct correlation of arginine levels with guanidinoacetate in patients with urea cycle disorders explains the increased concentration of guanidino compounds in arginase deficiency. Low creatine levels in some patients with other urea cycle defects might be explained by low protein intake (creatine is naturally present in meat) and relative or absolute intracellular arginine deficiency.
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Key Words
- AGAT, arginine glycine amidinotransferase
- ASL, argininosuccinate lyase
- ASS, argininosuccinate synthase
- Arginase deficiency
- Arginine
- CT1, creatine transporter 1
- Creatine
- Creatine deficiency
- GAA, guanidinoacetate
- GAMT, guanidino acetate methyltransferase
- Guanidinoacetate
- NOS, nitric oxide synthase
- ORNT1, ornithine transporter 1
- OTC, ornithine transcarbamylase
- SLC6A8, solute carrier family 6 member 8 gene
- UCD, urea cycle disorders
- Urea cycle defect
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Affiliation(s)
- Filippo Ingoglia
- Department of Pathology, University of Utah, Salt Lake City, UT 84108, USA.,ARUP Laboratories, 500 Chipeta Way, Salt Lake City, UT 84108, USA
| | - Jean-Leon Chong
- Department of Pathology, University of Utah, Salt Lake City, UT 84108, USA.,ARUP Laboratories, 500 Chipeta Way, Salt Lake City, UT 84108, USA
| | - Marzia Pasquali
- Department of Pathology, University of Utah, Salt Lake City, UT 84108, USA.,Department of Pediatrics, University of Utah, Salt Lake City, UT 84108, USA.,ARUP Laboratories, 500 Chipeta Way, Salt Lake City, UT 84108, USA
| | - Nicola Longo
- Department of Pathology, University of Utah, Salt Lake City, UT 84108, USA.,Department of Pediatrics, University of Utah, Salt Lake City, UT 84108, USA.,ARUP Laboratories, 500 Chipeta Way, Salt Lake City, UT 84108, USA
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5
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Balfoort BM, Buijs MJN, Ten Asbroek ALMA, Bergen AAB, Boon CJF, Ferreira EA, Houtkooper RH, Wagenmakers MAEM, Wanders RJA, Waterham HR, Timmer C, van Karnebeek CD, Brands MM. A review of treatment modalities in gyrate atrophy of the choroid and retina (GACR). Mol Genet Metab 2021; 134:96-116. [PMID: 34340878 DOI: 10.1016/j.ymgme.2021.07.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 07/02/2021] [Accepted: 07/23/2021] [Indexed: 12/29/2022]
Abstract
UNLABELLED Gyrate atrophy of the choroid and retina (GACR) is a rare inborn error of amino acid metabolism caused by bi-allelic variations in OAT. GACR is characterised by vision decline in early life eventually leading to complete blindness, and high plasma ornithine levels. There is no curative treatment for GACR, although several therapeutic modalities aim to slow progression of the disease by targeting different steps within the ornithine pathway. No international treatment protocol is available. We systematically collected all international literature on therapeutic interventions in GACR to provide an overview of published treatment effects. METHODS Following the PRISMA guidelines, we conducted a systematic review of the English literature until December 22nd 2020. PubMed and Embase databases were searched for studies related to therapeutic interventions in patients with GACR. RESULTS A total of 33 studies (n = 107 patients) met the inclusion criteria. Most studies were designed as case reports (n = 27) or case series (n = 4). No randomised controlled trials or large cohort studies were found. Treatments applied were protein-restricted diets, pyridoxine supplementation, creatine or creatine precursor supplementation, l-lysine supplementation, and proline supplementation. Protein-restricted diets lowered ornithine levels ranging from 16.0-91.2%. Pyridoxine responsiveness was reported in 30% of included mutations. Lysine supplementation decreased ornithine levels with 21-34%. Quality assessment showed low to moderate quality of the articles. CONCLUSIONS Based primarily on case reports ornithine levels can be reduced by using a protein restricted diet, pyridoxine supplementation (variation-dependent) and/or lysine supplementation. The lack of pre-defined clinical outcome measures and structural follow-up in all included studies impeded conclusions on clinical effectiveness. Future research should be aimed at 1) Unravelling the OAT biochemical pathway to identify other possible pathologic metabolites besides ornithine, 2) Pre-defining GACR specific clinical outcome measures, and 3) Establishing an international historical cohort.
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Affiliation(s)
- Berith M Balfoort
- Department of Paediatrics, Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, 1105, AZ, Amsterdam, the Netherlands
| | - Mark J N Buijs
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, 1105, AZ, Amsterdam, the Netherlands
| | - Anneloor L M A Ten Asbroek
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, 1105, AZ, Amsterdam, the Netherlands
| | - Arthur A B Bergen
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, 1105, AZ, Amsterdam, the Netherlands; Department of Ophthalmology, Amsterdam UMC, University of Amsterdam, 1105, AZ, Amsterdam, the Netherlands
| | - Camiel J F Boon
- Department of Ophthalmology, Amsterdam UMC, University of Amsterdam, 1105, AZ, Amsterdam, the Netherlands; Department of Ophthalmology, Leiden University Medical Centre, 2333, ZA, Leiden, the Netherlands
| | - Elise A Ferreira
- Department of Paediatrics, Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, 1105, AZ, Amsterdam, the Netherlands
| | - Riekelt H Houtkooper
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology, Endocrinology, and Metabolism, Amsterdam UMC, University of Amsterdam, 1105, AZ, Amsterdam, the Netherlands
| | - Margreet A E M Wagenmakers
- Department of Internal Medicine, Centre for Lysosomal and Metabolic Diseases, Erasmus MC, University Medical Centre Rotterdam, the Netherlands
| | - Ronald J A Wanders
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology, Endocrinology, and Metabolism, Amsterdam UMC, University of Amsterdam, 1105, AZ, Amsterdam, the Netherlands
| | - Hans R Waterham
- Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology, Endocrinology, and Metabolism, Amsterdam UMC, University of Amsterdam, 1105, AZ, Amsterdam, the Netherlands
| | - Corrie Timmer
- Department Endocrinology and Metabolism Amsterdam UMC, University of Amsterdam, 1105, AZ, Amsterdam, the Netherlands
| | - Clara D van Karnebeek
- Department of Paediatrics, Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, 1105, AZ, Amsterdam, the Netherlands; Department of Paediatrics, Radboud Centre for Mitochondrial Medicine, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Marion M Brands
- Department of Paediatrics, Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, 1105, AZ, Amsterdam, the Netherlands.
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Ostojic SM, Ratgeber L, Olah A, Betlehem J, Acs P. Guanidinoacetic acid deficiency: a new entity in clinical medicine? Int J Med Sci 2020; 17:2544-2550. [PMID: 33029096 PMCID: PMC7532483 DOI: 10.7150/ijms.47757] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 07/10/2020] [Indexed: 02/07/2023] Open
Abstract
Guanidinoacetic acid (GAA, also known as glycocyamine or betacyamine) is a naturally-occurring derivative of glycine and a direct metabolic precursor of creatine, a key player in high-phosphate cellular bioenergetics. GAA is found in human serum and urine, with circulating GAA likely reflects an equilibrium between its endogenous production and utilization/excretion. GAA deficiency (as indicated by low serum GAA) has been reported in various conditions yet this intriguing clinical entity appears to be poorly characterized as yet, either as a primary deficit or a sequel of secondary disease. This minireview article summarizes the inherited and acquired disorders with apparent GAA deficiency and discusses a possible relevance of GAA shortfall in clinical medicine.
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Affiliation(s)
- Sergej M Ostojic
- FSPE Applied Bioenergetics Lab, University of Novi Sad, Novi Sad, Serbia.,Faculty of Health Sciences, University of Pecs, Pecs, Hungary
| | - Laszlo Ratgeber
- Faculty of Health Sciences, University of Pecs, Pecs, Hungary
| | - Andras Olah
- Faculty of Health Sciences, University of Pecs, Pecs, Hungary
| | - Jozsef Betlehem
- Faculty of Health Sciences, University of Pecs, Pecs, Hungary
| | - Pongras Acs
- Faculty of Health Sciences, University of Pecs, Pecs, Hungary
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7
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Gene-metabolite profile integration to understand the cause of spaceflight induced immunodeficiency. NPJ Microgravity 2018; 4:4. [PMID: 29387784 PMCID: PMC5788863 DOI: 10.1038/s41526-017-0038-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 11/06/2017] [Accepted: 12/28/2017] [Indexed: 12/15/2022] Open
Abstract
Spaceflight presents a spectrum of stresses very different from those associated with terrestrial conditions. Our previous study (BMC Genom. 15: 659, 2014) integrated the expressions of mRNAs, microRNAs, and proteins and results indicated that microgravity induces an immunosuppressive state that can facilitate opportunistic pathogenic attack. However, the existing data are not sufficient for elucidating the molecular drivers of the given immunosuppressed state. To meet this knowledge gap, we focused on the metabolite profile of spaceflown human cells. Independent studies have attributed cellular energy deficiency as a major cause of compromised immunity of the host, and metabolites that are closely associated with energy production could be a robust signature of atypical energy fluctuation. Our protocol involved inoculation of human endothelial cells in cell culture modules in spaceflight and on the ground concurrently. Ten days later, the cells in space and on the ground were exposed to lipopolysaccharide (LPS), a ubiquitous membrane endotoxin of Gram-negative bacteria. Nucleic acids, proteins, and metabolites were collected 4 and 8 h post-LPS exposure. Untargeted profiling of metabolites was followed by targeted identification of amino acids and knowledge integration with gene expression profiles. Consistent with the past reports associating microgravity with increased energy expenditure, we identified several markers linked to energy deficiency, including various amino acids such as tryptophan, creatinine, dopamine, and glycine, and cofactors such as lactate and pyruvate. The present study revealed a molecular architecture linking energy metabolism and immunodeficiency in microgravity. The energy-deficient condition potentially cascaded into dysregulation of protein metabolism and impairment of host immunity. This project is limited by a small sample size. Although a strict statistical screening was carefully implemented, the present results further emphasize the need for additional studies with larger sample sizes. Validating this hypothesis using an in vivo model is essential to extend the knowledge towards identifying markers of diagnostic and therapeutic value. Human cells challenged with a bacterial toxin show more signs of energy deficiency when flown in space than when cultured on the ground. Rasha Hammamieh from the US Army Center for Environmental Health Research in Frederick, Maryland, and colleagues exposed human endothelial cells in spaceflight to lipopolysaccharide, an immune response-triggering part of the bacterial membrane. They then collected nucleic acids, proteins and metabolites 4 and 8 h later, and saw a molecular architecture consistent with increased energy expenditure compared to matched control cells grown on Earth. Combined with the researchers’ previous finding that microgravity can induce an immunosuppressive state, the results suggest that energy imbalances potentially lead to problems with protein metabolism that ultimately impair the immune system. The authors propose that reversing this energy depletion could help enhance the immune health of astronauts.
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8
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Ginguay A, Cynober L, Curis E, Nicolis I. Ornithine Aminotransferase, an Important Glutamate-Metabolizing Enzyme at the Crossroads of Multiple Metabolic Pathways. BIOLOGY 2017; 6:biology6010018. [PMID: 28272331 PMCID: PMC5372011 DOI: 10.3390/biology6010018] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 02/23/2017] [Accepted: 02/24/2017] [Indexed: 02/06/2023]
Abstract
Ornithine δ-aminotransferase (OAT, E.C. 2.6.1.13) catalyzes the transfer of the δ-amino group from ornithine (Orn) to α-ketoglutarate (aKG), yielding glutamate-5-semialdehyde and glutamate (Glu), and vice versa. In mammals, OAT is a mitochondrial enzyme, mainly located in the liver, intestine, brain, and kidney. In general, OAT serves to form glutamate from ornithine, with the notable exception of the intestine, where citrulline (Cit) or arginine (Arg) are end products. Its main function is to control the production of signaling molecules and mediators, such as Glu itself, Cit, GABA, and aliphatic polyamines. It is also involved in proline (Pro) synthesis. Deficiency in OAT causes gyrate atrophy, a rare but serious inherited disease, a further measure of the importance of this enzyme.
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Affiliation(s)
- Antonin Ginguay
- Clinical Chemistry, Cochin Hospital, GH HUPC, AP-HP, 75014 Paris, France.
- Laboratory of Biological Nutrition, EA 4466 PRETRAM, Faculté de Pharmacie, Université Paris Descartes, 75006 Paris, France.
| | - Luc Cynober
- Clinical Chemistry, Cochin Hospital, GH HUPC, AP-HP, 75014 Paris, France.
- Laboratory of Biological Nutrition, EA 4466 PRETRAM, Faculté de Pharmacie, Université Paris Descartes, 75006 Paris, France.
| | - Emmanuel Curis
- Laboratoire de biomathématiques, plateau iB², Faculté de Pharmacie, Université Paris Descartes, 75006 Paris, France.
- UMR 1144, INSERM, Université Paris Descartes, 75006 Paris, France.
- UMR 1144, Université Paris Descartes, 75006 Paris, France.
- Service de biostatistiques et d'informatique médicales, hôpital Saint-Louis, Assistance publique-hôpitaux de Paris, 75010 Paris, France.
| | - Ioannis Nicolis
- Laboratoire de biomathématiques, plateau iB², Faculté de Pharmacie, Université Paris Descartes, 75006 Paris, France.
- EA 4064 "Épidémiologie environnementale: Impact sanitaire des pollutions", Faculté de Pharmacie, Université Paris Descartes, 75006 Paris, France.
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Rackayova V, Cudalbu C, Pouwels PJW, Braissant O. Creatine in the central nervous system: From magnetic resonance spectroscopy to creatine deficiencies. Anal Biochem 2016; 529:144-157. [PMID: 27840053 DOI: 10.1016/j.ab.2016.11.007] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 11/08/2016] [Accepted: 11/09/2016] [Indexed: 10/20/2022]
Abstract
Creatine (Cr) is an important organic compound acting as intracellular high-energy phosphate shuttle and in energy storage. While located in most cells where it plays its main roles in energy metabolism and cytoprotection, Cr is highly concentrated in muscle and brain tissues, in which Cr also appears to act in osmoregulation and neurotransmission. This review discusses the basis of Cr metabolism, synthesis and transport within brain cells. The importance of Cr in brain function and the consequences of its impaired metabolism in primary and secondary Cr deficiencies are also discussed. Cr and phosphocreatine (PCr) in living systems can be well characterized using in vivo magnetic resonance spectroscopy (MRS). This review describes how 1H MRS allows the measurement of Cr and PCr, and how 31P MRS makes it possible to estimate the creatine kinase (CK) rate constant and so detect dynamic changes in the Cr/PCr/CK system. Absolute quantification by MRS using creatine as internal reference is also debated. The use of in vivo MRS to study brain Cr in a non-invasive way is presented, as well as its use in clinical and preclinical studies, including diagnosis and treatment follow-up in patients.
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Affiliation(s)
- Veronika Rackayova
- Laboratory of Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Cristina Cudalbu
- Centre d'Imagerie Biomedicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Petra J W Pouwels
- Department of Physics and Medical Technology, VU University Medical Center, Amsterdam, The Netherlands
| | - Olivier Braissant
- Service of Biomedicine, Neurometabolic Unit, Lausanne University Hospital, Lausanne, Switzerland.
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10
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Joncquel-Chevalier Curt M, Voicu PM, Fontaine M, Dessein AF, Porchet N, Mention-Mulliez K, Dobbelaere D, Soto-Ares G, Cheillan D, Vamecq J. Creatine biosynthesis and transport in health and disease. Biochimie 2015; 119:146-65. [DOI: 10.1016/j.biochi.2015.10.022] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 10/27/2015] [Indexed: 12/31/2022]
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11
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Martinelli D, Diodato D, Ponzi E, Monné M, Boenzi S, Bertini E, Fiermonte G, Dionisi-Vici C. The hyperornithinemia-hyperammonemia-homocitrullinuria syndrome. Orphanet J Rare Dis 2015; 10:29. [PMID: 25874378 PMCID: PMC4358699 DOI: 10.1186/s13023-015-0242-9] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 02/13/2015] [Indexed: 02/07/2023] Open
Abstract
Background Hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome is a rare autosomal recessive disorder of the urea cycle. HHH has a panethnic distribution, with a major prevalence in Canada, Italy and Japan. Acute clinical signs include intermittent episodes of vomiting, confusion or coma and hepatitis-like attacks. Alternatively, patients show a chronic course with aversion for protein rich foods, developmental delay/intellectual disability, myoclonic seizures, ataxia and pyramidal dysfunction. HHH syndrome is caused by impaired ornithine transport across the inner mitochondrial membrane due to mutations in SLC25A15 gene, which encodes for the mitochondrial ornithine carrier ORC1. The diagnosis relies on clinical signs and the peculiar metabolic triad of hyperammonemia, hyperornithinemia, and urinary excretion of homocitrulline. HHH syndrome enters in the differential diagnosis with other inherited or acquired conditions presenting with hyperammonemia. Methods A systematic review of publications reporting patients with HHH syndrome was performed. Results We retrospectively evaluated the clinical, biochemical and genetic profile of 111 HHH syndrome patients, 109 reported in 61 published articles, and two unpublished cases. Lethargy and coma are frequent at disease onset, whereas pyramidal dysfunction and cognitive/behavioural abnormalities represent the most common clinical features in late-onset cases or during the disease course. Two common mutations, F188del and R179* account respectively for about 30% and 15% of patients with the HHH syndrome. Interestingly, the majority of mutations are located in residues that have side chains protruding into the internal pore of ORC1, suggesting their possible interference with substrate translocation. Acute and chronic management consists in the control of hyperammonemia with protein-restricted diet supplemented with citrulline/arginine and ammonia scavengers. Prognosis of HHH syndrome is variable, ranging from a severe course with disabling manifestations to milder variants compatible with an almost normal life. Conclusions This paper provides detailed information on the clinical, metabolic and genetic profiles of all HHH syndrome patients published to date. The clinical phenotype is extremely variable and its severity does not correlate with the genotype or with recorded ammonium/ornithine plasma levels. Early intervention allows almost normal life span but the prognosis is variable, suggesting the need for a better understanding of the still unsolved pathophysiology of the disease. Electronic supplementary material The online version of this article (doi:10.1186/s13023-015-0242-9) contains supplementary material, which is available to authorized users.
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12
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Rae CD. A Guide to the Metabolic Pathways and Function of Metabolites Observed in Human Brain 1H Magnetic Resonance Spectra. Neurochem Res 2013; 39:1-36. [PMID: 24258018 DOI: 10.1007/s11064-013-1199-5] [Citation(s) in RCA: 320] [Impact Index Per Article: 29.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Revised: 11/08/2013] [Accepted: 11/11/2013] [Indexed: 12/20/2022]
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13
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Cheillan D, Curt MJC, Briand G, Salomons GS, Mention-Mulliez K, Dobbelaere D, Cuisset JM, Lion-François L, Portes VD, Chabli A, Valayannopoulos V, Benoist JF, Pinard JM, Simard G, Douay O, Deiva K, Afenjar A, Héron D, Rivier F, Chabrol B, Prieur F, Cartault F, Pitelet G, Goldenberg A, Bekri S, Gerard M, Delorme R, Tardieu M, Porchet N, Vianey-Saban C, Vamecq J. Screening for primary creatine deficiencies in French patients with unexplained neurological symptoms. Orphanet J Rare Dis 2012; 7:96. [PMID: 23234264 PMCID: PMC3552865 DOI: 10.1186/1750-1172-7-96] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Accepted: 12/07/2012] [Indexed: 12/11/2022] Open
Abstract
A population of patients with unexplained neurological symptoms from six major French university hospitals was screened over a 28-month period for primary creatine disorder (PCD). Urine guanidinoacetate (GAA) and creatine:creatinine ratios were measured in a cohort of 6,353 subjects to identify PCD patients and compile their clinical, 1H-MRS, biochemical and molecular data. Six GAMT [N-guanidinoacetatemethyltransferase (EC 2.1.1.2)] and 10 X-linked creatine transporter (SLC6A8) but no AGAT (GATM) [L-arginine/glycine amidinotransferase (EC 2.1.4.1)] deficient patients were identified in this manner. Three additional affected sibs were further identified after familial inquiry (1 brother with GAMT deficiency and 2 brothers with SLC6A8 deficiency in two different families). The prevalence of PCD in this population was 0.25% (0.09% and 0.16% for GAMT and SLC6A8 deficiencies, respectively). Seven new PCD-causing mutations were discovered (2 nonsense [c.577C > T and c.289C > T] and 1 splicing [c.391 + 15G > T] mutations for the GAMT gene and, 2 missense [c.1208C > A and c.926C > A], 1 frameshift [c.930delG] and 1 splicing [c.1393-1G > A] mutations for the SLC6A8 gene). No hot spot mutations were observed in these genes, as all the mutations were distributed throughout the entire gene sequences and were essentially patient/family specific. Approximately one fifth of the mutations of SLC6A8, but not GAMT, were attributed to neo-mutation, germinal or somatic mosaicism events. The only SLC6A8-deficient female patient in our series presented with the severe phenotype usually characterizing affected male patients, an observation in agreement with recent evidence that is in support of the fact that this X-linked disorder might be more frequent than expected in the female population with intellectual disability.
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Affiliation(s)
- David Cheillan
- Hospices Civils de Lyon, Service Maladies Héréditaires du Métabolisme et Dépistage Néonatal, Groupement Hospitalier Est, Bron, 69677, France
| | - Marie Joncquel-Chevalier Curt
- Département de Biochimie et Biologie Moléculaire, Laboratoire d’Hormonologie, Métabolisme-Nutrition & Oncologie (HMNO)–Centre de Biologie et Pathologie (CBP) Pierre-Marie Degand, CHRU Lille, Lille, 59037, France
| | - Gilbert Briand
- Département de Biochimie et Biologie Moléculaire, Laboratoire d’Hormonologie, Métabolisme-Nutrition & Oncologie (HMNO)–Centre de Biologie et Pathologie (CBP) Pierre-Marie Degand, CHRU Lille, Lille, 59037, France
- Mass Spectrometry Application Laboratory, University of Lille 2, Lille, 59045, France
| | - Gajja S Salomons
- Metabolic Unit, Department of Clinical Chemistry, VU University Medical Center Amsterdam, Amsterdam, The Netherlands
| | - Karine Mention-Mulliez
- Centre de Référence des Maladies Héréditaires du Métabolisme, Hôpital Jeanne de Flandres, CHRU Lille, Lille, 59037, France
| | - Dries Dobbelaere
- Centre de Référence des Maladies Héréditaires du Métabolisme, Hôpital Jeanne de Flandres, CHRU Lille, Lille, 59037, France
| | - Jean-Marie Cuisset
- Service de Neurologie Infantile, Hôpital Roger Salengro, CHRU Lille, Lille, 59037, France
| | - Laurence Lion-François
- Service de neurologie pédiatrique, CHU de Lyon-GH Est - Hôpital Femme Mère Enfant, Bron Cedex, 69677, France
| | - Vincent Des Portes
- Service de neurologie pédiatrique, CHU de Lyon-GH Est - Hôpital Femme Mère Enfant, Bron Cedex, 69677, France
| | - Allel Chabli
- Laboratory of Biochemistry, Necker – Enfants Malades Hospital and Université Paris Descartes, Paris, 75015, France
| | - Vassili Valayannopoulos
- Centre de Référence des Maladies Héréditaires du Métabolisme, Hôpital Necker des Enfants Malades and Université Paris Descartes, 149 rue de Sèvres, Paris, 75015, France
| | - Jean-François Benoist
- Département de Biochimie-Hormonologie, CHU Hôpital Robert Debré, Paris, 75019, France
| | - Jean-Marc Pinard
- Unité de Neurologie Pédiatrique, Département de Pédiatrie, Hôpital Raymond Poincare, Paris-IdF-Ouest University, Paris, France
| | - Gilles Simard
- Laboratoire de Biochimie et Biologie Moléculaire, CHU Angers, Angers, 49033, France
| | - Olivier Douay
- Laboratoire de Biochimie et Biologie Moléculaire, CHU Angers, Angers, 49033, France
| | - Kumaran Deiva
- Service de Neuropédiatrie - CHU de Bicêtre, Le Kremlin Bicêtre Cedex, 94275, France
| | - Alexandra Afenjar
- Service de Neuropédiatrie, Hôpital Armand Trousseau, Groupement hospitalier universitaire Est, Paris, 75012, France
| | - Delphine Héron
- Unité Fonctionnelle de Génétique Médicale AP-HP, Département de Génétique et Cytogénétique, Centre de Référence «Déficiences intellectuelles de causes rares », CRicm, UMR-S975, Groupe Hospitalier Pitié-Salpêtrière, Paris, F-75013, France
| | - François Rivier
- Neuropédiatrie, CHRU Montpellier, & Inserm U1046, Université Montpellier 1 & 2, Montpellier Cedex 5, 34295, France
| | - Brigitte Chabrol
- Service Neuropédiatrie, AP-HM Hôpital de la Timone, Marseille Cedex 5, 13385, France
| | - Fabienne Prieur
- Service de Génétique, CHU de Saint-Étienne Hôpital Nord, Saint-Etienne Cédex 2, 42055, France
| | - François Cartault
- Service de génétique Centre hospitalier Felix Guyon (Saint-Denis) Bellepierre, Saint-Denis cedex, 97405, France
| | - Gaëlle Pitelet
- Service de Neuropédiatrie, Hôpital de l’Archet 2, Nice Cedex 3, 06202, France
| | - Alice Goldenberg
- Service de Génétique Médicale, CHU Ch. Nicolle, Rouen Cedex, 76031, France
| | - Soumeya Bekri
- Institut de Biologie Clinique, CHU Ch. Nicolle, Rouen Cedex, 76031, France
| | - Marion Gerard
- Service de Génétique, CHU Clémenceau, Caen, 14033, France
| | - Richard Delorme
- Service de Pédopsychiatrie CHU Hôpital Robert Debré, Paris, 75019, France
| | - Marc Tardieu
- Service de Neuropédiatrie - CHU de Bicêtre, Le Kremlin Bicêtre Cedex, 94275, France
| | - Nicole Porchet
- Département de Biochimie et Biologie Moléculaire, Laboratoire d’Hormonologie, Métabolisme-Nutrition & Oncologie (HMNO)–Centre de Biologie et Pathologie (CBP) Pierre-Marie Degand, CHRU Lille, Lille, 59037, France
| | - Christine Vianey-Saban
- Hospices Civils de Lyon, Service Maladies Héréditaires du Métabolisme et Dépistage Néonatal, Groupement Hospitalier Est, Bron, 69677, France
| | - Joseph Vamecq
- Département de Biochimie et Biologie Moléculaire, Laboratoire d’Hormonologie, Métabolisme-Nutrition & Oncologie (HMNO)–Centre de Biologie et Pathologie (CBP) Pierre-Marie Degand, CHRU Lille, Lille, 59037, France
- Inserm, Laboratoire Externe, Département du Prof. Nicole Porchet, HMNO, Centre de Biologie et Pathologie (CBP) Pierre-Marie Degand, CHRU Lille, Lille, 59037, France
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14
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Martinelli D, Häberle J, Rubio V, Giunta C, Hausser I, Carrozzo R, Gougeard N, Marco-Marín C, Goffredo BM, Meschini MC, Bevivino E, Boenzi S, Colafati GS, Brancati F, Baumgartner MR, Dionisi-Vici C. Understanding pyrroline-5-carboxylate synthetase deficiency: clinical, molecular, functional, and expression studies, structure-based analysis, and novel therapy with arginine. J Inherit Metab Dis 2012; 35:761-76. [PMID: 22170564 DOI: 10.1007/s10545-011-9411-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Revised: 09/29/2011] [Accepted: 10/06/2011] [Indexed: 12/21/2022]
Abstract
Δ(1)-Pyrroline-5-carboxylate synthetase (P5CS) catalyzes the first two steps of ornithine/proline biosynthesis. P5CS deficiency has been reported in three families, with patients presenting with cutis/joint laxity, cataracts, and neurodevelopmental delay. Only one family exhibited metabolic changes consistent with P5CS deficiency (low proline/ornithine/citrulline/arginine; fasting hyperammonemia). Here we report a new P5CS-deficient patient presenting the complete clinical/metabolic phenotype and carrying p.G93R and p.T299I substitutions in the γ-glutamyl kinase (γGK) component of P5CS. The effects of these substitutions are (1) tested in mutagenesis/functional studies with E.coli γGK, (2) rationalized by structural modelling, and (3) reflected in decreased P5CS protein in patient fibroblasts (shown by immunofluorescence). Using optical/electron microscopy on skin biopsy, we show collagen/elastin fiber alterations that may contribute to connective tissue laxity and are compatible with our angio-MRI finding of kinky brain vessels in the patient. MR spectroscopy revealed decreased brain creatine, which normalized after sustained arginine supplementation, with improvement of neurodevelopmental and metabolic parameters, suggesting a pathogenic role of brain creatine decrease and the value of arginine therapy. Morphological and functional studies of fibroblast mitochondria show that P5CS deficiency is not associated with the mitochondrial alterations observed in Δ(1)-pyrroline-5-carboxylate reductase deficiency (another proline biosynthesis defect presenting cutis laxa and neurological alterations).
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Affiliation(s)
- Diego Martinelli
- Division of Metabolism, Bambino Gesù Children's Hospital, Piazza Sant'Onofrio, 4, 00165 Rome, Italy.
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15
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Boenzi S, Pastore A, Martinelli D, Goffredo BM, Boiani A, Rizzo C, Dionisi-Vici C. Creatine metabolism in urea cycle defects. J Inherit Metab Dis 2012; 35:647-53. [PMID: 22644604 DOI: 10.1007/s10545-012-9494-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Revised: 04/26/2012] [Accepted: 04/28/2012] [Indexed: 12/12/2022]
Abstract
Creatine (Cr) and phosphocreatine play an essential role in energy storage and transmission. Maintenance of creatine pool is provided by the diet and by de novo synthesis, which utilizes arginine, glycine and s-adenosylmethionine as substrates. Three primary Cr deficiencies exists: arginine:glycine amidinotransferase deficiency, guanidinoacetate methyltransferase deficiency and the defect of Cr transporter SLC6A8. Secondary Cr deficiency is characteristic of ornithine-aminotransferase deficiency, whereas non-uniform Cr abnormalities have anecdotally been reported in patients with urea cycle defects (UCDs), a disease category related to arginine metabolism in which Cr must be acquired by de novo synthesis because of low dietary intake. To evaluate the relationships between ureagenesis and Cr synthesis, we systematically measured plasma Cr in a large series of UCD patients (i.e., OTC, ASS, ASL deficiencies, HHH syndrome and lysinuric protein intolerance). Plasma Cr concentrations in UCDs followed two different trends: patients with OTC and ASS deficiencies and HHH syndrome presented a significant Cr decrease, whereas in ASL deficiency and lysinuric protein intolerance Cr levels were significantly increased (23.5 vs. 82.6 μmol/L; p < 0.0001). This trend distribution appears to be regulated upon cellular arginine availability, highlighting its crucial role for both ureagenesis and Cr synthesis. Although decreased Cr contributes to the neurological symptoms in primary Cr deficiencies, still remains to be explored if an altered Cr metabolism may participate to CNS dysfunction also in patients with UCDs. Since arginine in most UCDs becomes a semi-essential aminoacid, measuring plasma Cr concentrations might be of help to optimize the dose of arginine substitution.
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Affiliation(s)
- Sara Boenzi
- Division of Metabolism and Research Unit of Metabolic Biochemistry, Bambino Gesù Children's Hospital, IRCCS, Piazza S. Onofrio 4, 00165, Rome, Italy.
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16
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de Sain-van der Velden MGM, Rinaldo P, Elvers B, Henderson M, Walter JH, Prinsen BHCMT, Verhoeven-Duif NM, de Koning TJ, van Hasselt P. The Proline/Citrulline Ratio as a Biomarker for OAT Deficiency in Early Infancy. JIMD Rep 2012; 6:95-9. [PMID: 23430945 PMCID: PMC3565682 DOI: 10.1007/8904_2011_122] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Revised: 11/22/2011] [Accepted: 11/30/2011] [Indexed: 01/18/2023] Open
Abstract
Deficiency of ornithine-δ-aminotransferase (OAT) in humans results in gyrate atrophy. Early diagnosis may allow initiation of treatment before irreversible damage has occurred. However, diagnosis is commonly delayed well into adulthood because of the nonspecific character of initial symptoms. Here, we report findings in a neonate who was evaluated because of a positive family history of OAT deficiency. The reversed enzymatic flux in early infancy resulted in borderline low ornithine concentration - evoking urea cycle disturbances - and increased proline. In addition, plasma citrulline was low. Consequently, the proline/citrulline ratio in plasma was increased compared to controls. To find out whether amino acid profiling in neonatal dried blood spots is suitable to detect OAT deficiency, we evaluated the original newborn dried blood spots of two affected patients and compared it with a database of >450,000 newborns tested in Minnesota since 2004. Proline concentrations (777 and 1,381 μmol/L) were above the 99 percentile (776 μmol/L) of the general population, and citrulline concentrations (4.5 and 4.9 μmol/L) only just above the 1 percentile (4.37 μmol/L). The proline/citrulline ratio was 172.9 and 281.8, respectively. This ratio was calculated retrospectively in the normal population, and the 99 percentile was 97.6. Applying this ratio for NBS could lead to early and specific detection of neonatal OAT deficiency, with no additional expense to newborn screening laboratories quantifying amino acids. Given that early diagnosis of OAT disease can lead to earlier treatment and prevent visual impairment, further studies are indicated to evaluate whether newborn screening for OAT deficiency is warranted.
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Affiliation(s)
- Monique G M de Sain-van der Velden
- Department of Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Centre (UMC) Utrecht, 85090, 3508, Utrecht, The Netherlands,
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17
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Boenzi S, Rizzo C, Di Ciommo VM, Martinelli D, Goffredo BM, la Marca G, Dionisi-Vici C. Simultaneous determination of creatine and guanidinoacetate in plasma by liquid chromatography–tandem mass spectrometry (LC–MS/MS). J Pharm Biomed Anal 2011; 56:792-8. [DOI: 10.1016/j.jpba.2011.06.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Revised: 05/31/2011] [Accepted: 06/09/2011] [Indexed: 11/28/2022]
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18
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Braissant O, Henry H, Béard E, Uldry J. Creatine deficiency syndromes and the importance of creatine synthesis in the brain. Amino Acids 2011; 40:1315-24. [DOI: 10.1007/s00726-011-0852-z] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2010] [Accepted: 11/25/2010] [Indexed: 10/18/2022]
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19
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Liu Y, Yang N, Hao W, Zhao Q, Ying T, Liu S, Li Q, Liang Y, Wang T, Dong Y, Ji C, Zuo P. Dynamic proteomic analysis of protein expression profiles in whole brain of Balb/C mice subjected to unpredictable chronic mild stress: implications for depressive disorders and future therapies. Neurochem Int 2011; 58:904-13. [PMID: 21349309 DOI: 10.1016/j.neuint.2011.02.019] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Revised: 02/11/2011] [Accepted: 02/16/2011] [Indexed: 01/26/2023]
Abstract
The etiology and pathophysiology of depression remain unknown. Previous works were mostly performed on single observation time-point which might be insufficiently to reveal the molecular events changed during the disease development. Adult BALB/c mice were exposed to unpredictable chronic mild stress (UCMS) for different periods and differential 2D gel electrophoresis (DIGE) approach was employed to the brain tissue to explore the molecular disease signatures. Sustained elevation of corticosterone level was observed, suggesting the hyperactivity of hypothalamic-pituitary-adrenal (HPA) axis when the mice were subjected to the stressful situation. The behavioral results indicated the depressive alterations of the mice exposing to UCMS. The altered proteins identified by proteomics showed that abnormal energy mobilization under stress condition was accompanied by overproduction of reactive oxygen species (ROS) and endoplasmic reticulum (ER) stress. Cytoskeleton protein and anti-oxidant enzymes were also changed by UCMS treatment. The results of biochemical and immunohistochemical assay confirmed the changes identified by DIGE analysis. These results indicated that the insufficiency of ATP synthesis, overwhelming ROS production and ER stress subsequently contributed to the cytoskeletal damage and inhibition to expression of some anti-oxidant proteins, which might ultimately bring functional neuron to apoptosis or death. Proteins whose expression is affected may provide tools for potential treatment strategies.
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Affiliation(s)
- Yanyong Liu
- Department of Pharmacology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, No. 5 Dongdansantiao, Beijing 100005, China
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20
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Viegas CM, Busanello ENB, Tonin AM, de Moura AP, Grings M, Ritter L, Schuck PF, Ferreira GDC, Sitta A, Vargas CR, Wajner M. Dual mechanism of brain damage induced in vivo by the major metabolites accumulating in hyperornithinemia–hyperammonemia–homocitrullinuria syndrome. Brain Res 2011; 1369:235-44. [DOI: 10.1016/j.brainres.2010.10.112] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Revised: 10/29/2010] [Accepted: 10/30/2010] [Indexed: 11/28/2022]
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21
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Béard E, Braissant O. Synthesis and transport of creatine in the CNS: importance for cerebral functions. J Neurochem 2010; 115:297-313. [DOI: 10.1111/j.1471-4159.2010.06935.x] [Citation(s) in RCA: 118] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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22
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Brosnan JT, Brosnan ME. Creatine metabolism and the urea cycle. Mol Genet Metab 2010; 100 Suppl 1:S49-52. [PMID: 20304692 DOI: 10.1016/j.ymgme.2010.02.020] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2009] [Accepted: 02/10/2010] [Indexed: 11/27/2022]
Abstract
Because creatine and creatine phosphate are irreversibly converted to creatinine, there is a continuous need for their replacement. This occurs by means of diet and de novo synthesis. Dietary creatine is provided in animal products and can amount to about half of the required amount. Synthesis provides the remainder. Creatine synthesis is a major component of arginine metabolism, amounting to more than 20% of the dietary intake of this amino acid. Creatine metabolism is of importance to patients with urea cycle disorders in two ways, both related to arginine levels. In patients with arginase deficiency, markedly elevated arginine levels may result in higher concentrations of guanidinoacetate and higher rates of creatine synthesis. This is of concern because it is thought that elevated levels of guanidinoacetate may exert neurotoxic effects. In the case of the other urea cycle disorders, arginine levels are markedly decreased unless the patients are supplemented with this amino acid. Decreased levels of arginine may result in decreased rates of creatine synthesis. This may be compounded by the fact that such patients, maintained on low protein diets, will also have lower dietary creatine intakes. There is some evidence that this may decrease brain creatine levels which may contribute to the neurological symptoms exhibited by these patients. It is clear that patients with urea cycle disorders also have altered creatine metabolism. Whether this contributes in a significant way to their neurological symptoms remains an open question.
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Affiliation(s)
- John T Brosnan
- Department of Biochemistry, Memorial University of Newfoundland, St. John's, NL, Canada.
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23
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García Silva MT. [Brain creatine defects: how can these uncommon diseases be diagnosed and their evolution changed]. Med Clin (Barc) 2009; 133:752-3. [PMID: 19880147 DOI: 10.1016/j.medcli.2009.09.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Accepted: 09/07/2009] [Indexed: 10/20/2022]
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