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Ruiz-Sala P, Peña-Quintana L. Biochemical Markers for the Diagnosis of Mitochondrial Fatty Acid Oxidation Diseases. J Clin Med 2021; 10:jcm10214855. [PMID: 34768374 PMCID: PMC8584803 DOI: 10.3390/jcm10214855] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/07/2021] [Accepted: 10/19/2021] [Indexed: 12/30/2022] Open
Abstract
Mitochondrial fatty acid β-oxidation (FAO) contributes a large proportion to the body’s energy needs in fasting and in situations of metabolic stress. Most tissues use energy from fatty acids, particularly the heart, skeletal muscle and the liver. In the brain, ketone bodies formed from FAO in the liver are used as the main source of energy. The mitochondrial fatty acid oxidation disorders (FAODs), which include the carnitine system defects, constitute a group of diseases with several types and subtypes and with variable clinical spectrum and prognosis, from paucisymptomatic cases to more severe affectations, with a 5% rate of sudden death in childhood, and with fasting hypoketotic hypoglycemia frequently occurring. The implementation of newborn screening programs has resulted in new challenges in diagnosis, with the detection of new phenotypes as well as carriers and false positive cases. In this article, a review of the biochemical markers used for the diagnosis of FAODs is presented. The analysis of acylcarnitines by MS/MS contributes to improving the biochemical diagnosis, both in affected patients and in newborn screening, but acylglycines, organic acids, and other metabolites are also reported. Moreover, this review recommends caution, and outlines the differences in the interpretation of the biomarkers depending on age, clinical situation and types of samples or techniques.
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Affiliation(s)
- Pedro Ruiz-Sala
- Centro de Diagnóstico de Enfermedades Moleculares, Universidad Autónoma Madrid, CIBERER, IDIPAZ, 28049 Madrid, Spain;
| | - Luis Peña-Quintana
- Pediatric Gastroenterology, Hepatology and Nutrition Unit, Mother and Child Insular University Hospital Complex, Asociación Canaria para la Investigación Pediátrica (ACIP), CIBEROBN, University Institute for Research in Biomedical and Health Sciences, University of Las Palmas de Gran Canaria, 35016 Las Palmas de Gran Canaria, Spain
- Correspondence:
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Haam JH, Lee YK, Suh E, Choi SW, Chun H, Kim YS. Urine organic acids may be useful biomarkers for metabolic syndrome and its components in Korean adults. Clin Chem Lab Med 2021; 59:1824-1831. [PMID: 34331849 DOI: 10.1515/cclm-2021-0598] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 07/20/2021] [Indexed: 12/20/2022]
Abstract
OBJECTIVES Although metabolic syndrome (MetS) and its components are defined clinically, those with MetS may have various derangements in metabolic pathways. Thus, this study aimed to evaluate the traits of urine organic acid metabolites indicating the metabolic intermediates of the pathways in the subjects with MetS. METHODS This cross-sectional study included 246 men and 283 women in a hospital health check-up setting. Urine organic acid metabolites were assayed via high-performance liquid chromatography-mass spectrometry analyses. A high level of each metabolite was defined as the fifth quintile of the distribution. RESULTS The subjects with MetS had high levels of pyruvate, α-ketoglutarate, α-ketoisovalerate, α-ketoisocaproate, formiminoglutamate, and quinolinate (odds ratios from 1.915 to 2.809 in logistic models adjusted for age and sex). Among the metabolites, pyruvate, formiminoglutamate, and quinolinate were not independent of homeostatic model assessment of insulin resistance (HOMA2-IR). Several metabolites were associated with one or more components of MetS and HOMA2-IR. CONCLUSIONS Urine organic acid metabolites in MetS are characterized in altered carbohydrate and amino acid metabolism. MetS shared some traits in insulin resistance. These findings may promote the understanding of the pathophysiology of MetS.
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Affiliation(s)
- Ji-Hee Haam
- Chaum Life Center, CHA University, Seoul, Korea
| | | | | | | | - Hyejin Chun
- Department of Family medicine, CHA Bundang Medical Center, CHA University, Seongnam, Korea
| | - Young-Sang Kim
- Department of Family medicine, CHA Bundang Medical Center, CHA University, Seongnam, Korea
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Pasqua T, Rocca C, Giglio A, Angelone T. Cardiometabolism as an Interlocking Puzzle between the Healthy and Diseased Heart: New Frontiers in Therapeutic Applications. J Clin Med 2021; 10:721. [PMID: 33673114 PMCID: PMC7918460 DOI: 10.3390/jcm10040721] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/05/2021] [Accepted: 02/07/2021] [Indexed: 12/14/2022] Open
Abstract
Cardiac metabolism represents a crucial and essential connecting bridge between the healthy and diseased heart. The cardiac muscle, which may be considered an omnivore organ with regard to the energy substrate utilization, under physiological conditions mainly draws energy by fatty acids oxidation. Within cardiomyocytes and their mitochondria, through well-concerted enzymatic reactions, substrates converge on the production of ATP, the basic chemical energy that cardiac muscle converts into mechanical energy, i.e., contraction. When a perturbation of homeostasis occurs, such as an ischemic event, the heart is forced to switch its fatty acid-based metabolism to the carbohydrate utilization as a protective mechanism that allows the maintenance of its key role within the whole organism. Consequently, the flexibility of the cardiac metabolic networks deeply influences the ability of the heart to respond, by adapting to pathophysiological changes. The aim of the present review is to summarize the main metabolic changes detectable in the heart under acute and chronic cardiac pathologies, analyzing possible therapeutic targets to be used. On this basis, cardiometabolism can be described as a crucial mechanism in keeping the physiological structure and function of the heart; furthermore, it can be considered a promising goal for future pharmacological agents able to appropriately modulate the rate-limiting steps of heart metabolic pathways.
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Affiliation(s)
- Teresa Pasqua
- Department of Health Science, University Magna Graecia of Catanzaro, 88100 Catanzaro, Italy;
| | - Carmine Rocca
- Laboratory of Cellular and Molecular Cardiovascular Pathophysiology, Department of Biology, E. and E.S. (Di.B.E.S.T.), University of Calabria, 87036 Rende (CS), Italy
| | - Anita Giglio
- Department of Biology, E. and E.S. (Di.B.E.S.T.), University of Calabria, 87036 Rende (CS), Italy;
| | - Tommaso Angelone
- Laboratory of Cellular and Molecular Cardiovascular Pathophysiology, Department of Biology, E. and E.S. (Di.B.E.S.T.), University of Calabria, 87036 Rende (CS), Italy
- National Institute of Cardiovascular Research (I.N.R.C.), 40126 Bologna, Italy
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Increased antioxidant response in medium-chain acyl-CoA dehydrogenase deficiency: does lipoic acid have a protective role? Pediatr Res 2020; 88:556-564. [PMID: 32045933 DOI: 10.1038/s41390-020-0801-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 09/30/2019] [Accepted: 12/07/2019] [Indexed: 12/14/2022]
Abstract
BACKGROUND Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency (MCADD) is the most frequent fatty acid oxidation (FAO) defect in humans. MCAD-deficient fibroblasts are more resistant to oxidative stress-induced cell death than other FAO defects and healthy controls. METHODS Herein we investigate the antioxidant response and mitochondrial function in fibroblasts from MCAD-deficient patients (c.985 A>G/c.985 A>G) and healthy controls. RESULTS MCAD-deficient fibroblasts showed increased level of mitochondrial superoxide, while lipids were less oxidatively damaged, and higher amount of manganese superoxide dismutase were detected compared to healthy controls, showing forceful antioxidant system in MCADD. We showed increased maximal respiration and reserve capacity in MCAD-deficient fibroblasts compared to controls, indicating more capacity through the tricarboxylic acid (TCA) cycle and subsequently respiratory chain. This led us to study the pyruvate dehydrogenase complex (PDC), the key enzyme in the glycolysis releasing acetyl-CoA to the TCA cycle. MCAD-deficient fibroblasts displayed not only significantly increased PDC but also increased lipoylated PDC protein levels compared to healthy controls. CONCLUSIONS Based on these findings, we raise the interesting hypothesis that increased PDC-bound lipoic acid, synthesized from accumulated octanoic acid in MCADD, may affect the cellular antioxidant pool in MCADD.
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Abstract
Hypoglycemia in the pediatric population is a common finding important to recognize and manage to prevent brain injury. Recent advances in molecular genetics have provided new insight into its biochemical and physiologic basis and have led to more appropriate and specific treatment. Although a major cause of brain injury in pediatrics, the ability to predict the long-term outcome in these patients remains difficult. Identification of these at-risk individuals is important. The physiologic adaptations associated with transition from fetal to neonatal life are now better understood thus allowing for improved surveillance and management. Despite these advances, analytical limitations of point-of-care testing instruments at low glucose concentration continue to persist, This review aims to address these questions and provide an overview of pediatric hypoglycemia and the molecular pathways involved.
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Li M, Li C, Allen A, Stanley CA, Smith TJ. Glutamate dehydrogenase: structure, allosteric regulation, and role in insulin homeostasis. Neurochem Res 2013; 39:433-45. [PMID: 24122080 DOI: 10.1007/s11064-013-1173-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 09/26/2013] [Accepted: 10/03/2013] [Indexed: 02/02/2023]
Abstract
Glutamate dehydrogenase (GDH) is a homohexameric enzyme that catalyzes the reversible oxidative deamination of L-glutamate to 2-oxoglutarate. Only in the animal kingdom is this enzyme heavily allosterically regulated by a wide array of metabolites. The major activators are ADP and leucine and inhibitors include GTP, palmitoyl CoA, and ATP. Spontaneous mutations in the GTP inhibitory site that lead to the hyperinsulinism/hyperammonemia (HHS) syndrome have shed light as to why mammalian GDH is so tightly regulated. Patients with HHS exhibit hypersecretion of insulin upon consumption of protein and concomitantly extremely high levels of ammonium in the serum. The atomic structures of four new inhibitors complexed with GDH complexes have identified three different allosteric binding sites. Using a transgenic mouse model expressing the human HHS form of GDH, at least three of these compounds blocked the dysregulated form of GDH in pancreatic tissue. EGCG from green tea prevented the hyper-response to amino acids in whole animals and improved basal serum glucose levels. The atomic structure of the ECG-GDH complex and mutagenesis studies is directing structure-based drug design using these polyphenols as a base scaffold. In addition, all of these allosteric inhibitors are elucidating the atomic mechanisms of allostery in this complex enzyme.
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Affiliation(s)
- Ming Li
- Donald Danforth Plant Science Center, 975 North Warson Road, Saint Louis, MO, 63132, USA
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Affiliation(s)
- Robert J Courtney
- Case Eye Institute, Oregon Health and Science University, Portland, OR 97239, USA
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Li M, Li C, Allen A, Stanley CA, Smith TJ. The structure and allosteric regulation of mammalian glutamate dehydrogenase. Arch Biochem Biophys 2011; 519:69-80. [PMID: 22079166 DOI: 10.1016/j.abb.2011.10.015] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 10/19/2011] [Accepted: 10/25/2011] [Indexed: 01/10/2023]
Abstract
Glutamate dehydrogenase (GDH) is a homohexameric enzyme that catalyzes the reversible oxidative deamination of l-glutamate to 2-oxoglutarate. Only in the animal kingdom is this enzyme heavily allosterically regulated by a wide array of metabolites. The major activators are ADP and leucine, while the most important inhibitors include GTP, palmitoyl CoA, and ATP. Recently, spontaneous mutations in the GTP inhibitory site that lead to the hyperinsulinism/hyperammonemia (HHS) syndrome have shed light as to why mammalian GDH is so tightly regulated. Patients with HHS exhibit hypersecretion of insulin upon consumption of protein and concomitantly extremely high levels of ammonium in the serum. The atomic structures of four new inhibitors complexed with GDH complexes have identified three different allosteric binding sites. Using a transgenic mouse model expressing the human HHS form of GDH, at least three of these compounds were found to block the dysregulated form of GDH in pancreatic tissue. EGCG from green tea prevented the hyper-response to amino acids in whole animals and improved basal serum glucose levels. The atomic structure of the ECG-GDH complex and mutagenesis studies is directing structure-based drug design using these polyphenols as a base scaffold. In addition, all of these allosteric inhibitors are elucidating the atomic mechanisms of allostery in this complex enzyme.
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Affiliation(s)
- Ming Li
- Donald Danforth Plant Science Center, 975 North Warson Road, Saint Louis, MO 63132, USA
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Li C, Chen P, Palladino A, Narayan S, Russell LK, Sayed S, Xiong G, Chen J, Stokes D, Butt YM, Jones PM, Collins HW, Cohen NA, Cohen AS, Nissim I, Smith TJ, Strauss AW, Matschinsky FM, Bennett MJ, Stanley CA. Mechanism of hyperinsulinism in short-chain 3-hydroxyacyl-CoA dehydrogenase deficiency involves activation of glutamate dehydrogenase. J Biol Chem 2010; 285:31806-18. [PMID: 20670938 DOI: 10.1074/jbc.m110.123638] [Citation(s) in RCA: 132] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mechanism of insulin dysregulation in children with hyperinsulinism associated with inactivating mutations of short-chain 3-hydroxyacyl-CoA dehydrogenase (SCHAD) was examined in mice with a knock-out of the hadh gene (hadh(-/-)). The hadh(-/-) mice had reduced levels of plasma glucose and elevated plasma insulin levels, similar to children with SCHAD deficiency. hadh(-/-) mice were hypersensitive to oral amino acid with decrease of glucose level and elevation of insulin. Hypersensitivity to oral amino acid in hadh(-/-) mice can be explained by abnormal insulin responses to a physiological mixture of amino acids and increased sensitivity to leucine stimulation in isolated perifused islets. Measurement of cytosolic calcium showed normal basal levels and abnormal responses to amino acids in hadh(-/-) islets. Leucine, glutamine, and alanine are responsible for amino acid hypersensitivity in islets. hadh(-/-) islets have lower intracellular glutamate and aspartate levels, and this decrease can be prevented by high glucose. hadh(-/-) islets also have increased [U-(14)C]glutamine oxidation. In contrast, hadh(-/-) mice have similar glucose tolerance and insulin sensitivity compared with controls. Perifused hadh(-/-) islets showed no differences from controls in response to glucose-stimulated insulin secretion, even with addition of either a medium-chain fatty acid (octanoate) or a long-chain fatty acid (palmitate). Pull-down experiments with SCHAD, anti-SCHAD, or anti-GDH antibodies showed protein-protein interactions between SCHAD and GDH. GDH enzyme kinetics of hadh(-/-) islets showed an increase in GDH affinity for its substrate, α-ketoglutarate. These studies indicate that SCHAD deficiency causes hyperinsulinism by activation of GDH via loss of inhibitory regulation of GDH by SCHAD.
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Affiliation(s)
- Changhong Li
- Division of Endocrinology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
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Tyni T, Rapola J, Paetau A, Palotie A, Pihko H. Pathology of Long-Chain 3-Hydroxyacyl-Coa Dehydrogenase Deficiency Caused by the G1528C Mutation. ACTA ACUST UNITED AC 2010. [DOI: 10.1080/15513819709168585] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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11
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Dyke PC, Konczal L, Bartholomew D, McBride KL, Hoffman TM. Acute dilated cardiomyopathy in a patient with deficiency of long-chain 3-hydroxyacyl-CoA dehydrogenase. Pediatr Cardiol 2009; 30:523-6. [PMID: 19083141 DOI: 10.1007/s00246-008-9351-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Revised: 11/11/2008] [Accepted: 11/14/2008] [Indexed: 11/30/2022]
Abstract
Deficiency of long-chain 3-hydroxyacyl-coenzyme A (CoA) dehydrogenase (LCHADD) is a rare inborn error of metabolism. It is associated with hypertrophic cardiomyopathy and less frequently with dilated cardiomyopathy. The incidence and pathophysiology of cardiac involvement in LCHADD is poorly understood. This report describes the acute decompensation of a 3-year-old girl who had LCHADD with rapidly developing dilated cardiomyopathy. A review of the literature and possible causes of cardiomyopathy in LCHADD are explored.
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Affiliation(s)
- Peter C Dyke
- Department of Pediatrics, Nationwide Children's Hospital Heart Center, Columbus, OH 43205-2696, USA
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Tan TY, Amor DJ. Obesity, hypothyroidism, craniosynostosis, cardiac hypertrophy, colitis, and developmental delay: A novel syndrome. Am J Med Genet A 2007; 143A:114-8. [PMID: 17163533 DOI: 10.1002/ajmg.a.31548] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We describe in two brothers an apparently novel syndrome comprising obesity, congenital hypothyroidism, neonatal colitis, cardiac biventricular hypertrophy, craniosynostosis, and developmental delay. The first brother presented with neonatal colitis and congenital hypothyroidism and died at age 5 weeks of fulminant colitis. The second brother presented neonatally with the same condition, but survived and subsequently developed severe obesity, sagittal and coronal synostosis, and developmental delay. Both pregnancies had been complicated by hemolysis, elevated liver enzymes, and low platelets (HELLP syndrome). Exhaustive genetic and metabolic investigations have failed to provide a unifying pathogenesis. This unique combination of manifestations appears to represent a new syndrome with probable autosomal recessive or X-linked recessive inheritance.
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Affiliation(s)
- Tiong Yang Tan
- Genetic Health Services Victoria, Royal Children's Hospital, Melbourne, Australia. tiong.tan.org.au
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Hussain K, Clayton PT, Krywawych S, Chatziandreou I, Mills P, Ginbey DW, Geboers AJJM, Berger R, van den Berg IET, Eaton S. Hyperinsulinism of infancy associated with a novel splice site mutation in the SCHAD gene. J Pediatr 2005; 146:706-8. [PMID: 15870679 DOI: 10.1016/j.jpeds.2005.01.032] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Fatty acids play an important role in regulating insulin secretion, but the mechanisms are unclear. We report a case of a novel splice site mutation in the short-chain 3-hydroxyacyl-CoA dehydrogenase (SCHAD) gene associated with hyperinsulinism. This mutation resulted in a nearly complete absence of immunoreactive protein and a decrease in fibroblast SCHAD activity.
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Affiliation(s)
- Khalid Hussain
- London Centre for Paediatric Endocrinology and Metabolism, Biochemistry, Endocrinology and Metabolism Unit, Institute of Child Health, University College and Great Ormond Street Hospital for Children NHS Trust, 30 Guilford Street, London WC1N 1EH, UK
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Abstract
Carnitine deficiency is a secondary complication of many inborn errors of metabolism. Pharmacological treatment with carnitine not only corrects the deficiency, it facilitates removal of accumulating toxic acyl intermediates and the generation of mitochondrial free coenzyme A (CoA). The United States Food and Drug Administration (US FDA) approved the use of carnitine for the treatment of inborn errors of metabolism in 1992. This approval was based on retrospective chart analysis of 90 patients, with 18 in the untreated cohort and 72 in the treated cohort. Efficacy was evaluated on the basis of clinical and biochemical findings. Compelling data included increased excretion of disease-specific acylcarnitine derivatives in a dose-response relationship, decreased levels of metabolites in the blood, and improved clinical status with decreased hospitalization frequency, improved growth and significantly lower mortality rates as compared to historical controls. Complications of carnitine treatment were few, with gastrointestinal disturbances and odour being the most frequent. No laboratory or clinical safety issues were identified. Intravenous carnitine preparations were also approved for treatment of secondary carnitine deficiency. Since only 25% of enteral carnitine is absorbed and gastrointestinal tolerance of high doses is poor, parenteral carnitine treatment is an appealing alternative therapeutic approach. In 7 patients treated long term with high-dose weekly to daily venous boluses of parenteral carnitine through a subcutaneous venous port, benefits included decreased frequency of decompensations, improved growth, improved muscle strength and decreased reliance on medical foods with liberalization of protein intake. Port infections were the most troubling complication. Theoretical concerns continue to be voiced that carnitine might result in fatal arrhythmias in patients with long-chain fat metabolism defects. No published clinical studies substantiate these concerns. Carnitine treatment of inborn errors of metabolism is a safe and integral part of the treatment regime for these disorders.
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Affiliation(s)
- S C Winter
- UCSF, Children's Hospital Central California, 9300 Valley Children's Place, Madera, CA 93638, USA
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Lund AM, Dixon MA, Vreken P, Leonard JV, Morris AAM. What is the role of medium-chain triglycerides in the management of long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency? J Inherit Metab Dis 2003; 26:353-60. [PMID: 12971423 DOI: 10.1023/a:1025107119186] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Cardiomyopathy is common in infants with long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency. Resolution of the cardiomyopathy can often be achieved by avoidance of fasting and changing from a conventional infant formula to one in which most long-chain fat is replaced by medium-chain triglycerides (MCT). It is uncertain whether the clinical improvement is due to the restriction of long-chain fat or whether the MCT have specific beneficial effects. To clarify this, the metabolic effects of MCT were examined in 5 patients. When given at around the level found in MCT-based infant formula, MCT had no effect on blood concentrations of ketone bodies, specific fatty acids or acylcarnitines. The present study cannot, however, exclude the possibility that MCT per se may have beneficial effects.
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Affiliation(s)
- A M Lund
- Metabolic Department, Great Ormond Street Hospital for Children, London, UK
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Abstract
The control of mitochondrial beta-oxidation, including the delivery of acyl moieties from the plasma membrane to the mitochondrion, is reviewed. Control of beta-oxidation flux appears to be largely at the level of entry of acyl groups to mitochondria, but is also dependent on substrate supply. CPTI has much of the control of hepatic beta-oxidation flux, and probably exerts high control in intact muscle because of the high concentration of malonyl-CoA in vivo. beta-Oxidation flux can also be controlled by the redox state of NAD/NADH and ETF/ETFH(2). Control by [acetyl-CoA]/[CoASH] may also be significant, but it is probably via export of acyl groups by carnitine acylcarnitine translocase and CPT II rather than via accumulation of 3-ketoacyl-CoA esters. The sharing of control between CPTI and other enzymes allows for flexible regulation of metabolism and the ability to rapidly adapt beta-oxidation flux to differing requirements in different tissues.
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Affiliation(s)
- Simon Eaton
- Surgery Unit, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK.
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den Boer MEJ, Wanders RJA, Morris AAM, IJlst L, Heymans HSA, Wijburg FA. Long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency: clinical presentation and follow-up of 50 patients. Pediatrics 2002; 109:99-104. [PMID: 11773547 DOI: 10.1542/peds.109.1.99] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVES To assess the mode of presentation, biochemical abnormalities, clinical course, and effects of therapy in patients of long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency. BACKGROUND LCHAD deficiency is a rare, autosomal recessive inborn error of fatty acid oxidation. Although case reports and small series of patients have been published, these may not give a true picture of the clinical and biochemical spectrum associated with this disorder. To improve the early recognition and management of this potentially lethal disorder, we have reviewed a large cohort of LCHAD-deficient patients. METHODS A questionnaire was sent to the referring physicians of 61 unselected patients with LCHAD deficiency diagnosed in our center. The standardized questionnaire requested information about the clinical signs and symptoms at presentation, the clinical history, family history, pregnancy, biochemical parameters at presentation, treatment, and clinical outcome. RESULTS Questionnaires on 50 patients (82%) were returned and included in this study. The mean age of clinical presentation was 5.8 months (range: 1 day-26 months). Seven (15%) of the patients presented in the neonatal period. Thirty-nine patients (78%) presented with hypoketotic hypoglycemia, the classical features of a fatty acid oxidation disorder. Eleven patients (22%) presented with chronic problems, consisting of failure to thrive, feeding difficulties, cholestatic liver disease, and/or hypotonia. In retrospect, most (82%) of the patients presenting with an acute metabolic derangement also suffered from a combination of chronic nonspecific symptoms before the metabolic crises. Mortality in this series was high (38%), all dying before or within 3 months after diagnosis. Morbidity in the surviving patients is also high, with recurrent metabolic crises and muscle problems despite therapy. CONCLUSIONS LCHAD deficiency often presents with a combination of chronic nonspecific symptoms. Early diagnosis is difficult in the absence of the classical metabolic derangement. Survival can be improved by prompt diagnosis, but morbidity remains alarmingly high despite current therapeutic regimes.
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Clayton PT, Eaton S, Aynsley-Green A, Edginton M, Hussain K, Krywawych S, Datta V, Malingré HE, Berger R, van den Berg IE. Hyperinsulinism in short-chain L-3-hydroxyacyl-CoA dehydrogenase deficiency reveals the importance of β-oxidation in insulin secretion. J Clin Invest 2001. [DOI: 10.1172/jci200111294] [Citation(s) in RCA: 219] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Clayton PT, Eaton S, Aynsley-Green A, Edginton M, Hussain K, Krywawych S, Datta V, Malingre HE, Berger R, van den Berg IE. Hyperinsulinism in short-chain L-3-hydroxyacyl-CoA dehydrogenase deficiency reveals the importance of beta-oxidation in insulin secretion. J Clin Invest 2001; 108:457-65. [PMID: 11489939 PMCID: PMC209352 DOI: 10.1172/jci11294] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2000] [Accepted: 06/11/2001] [Indexed: 12/14/2022] Open
Abstract
A female infant of nonconsanguineous Indian parents presented at 4 months with a hypoglycemic convulsion. Further episodes of hypoketotic hypoglycemia were associated with inappropriately elevated plasma insulin concentrations. However, unlike other children with hyperinsulinism, this patient had a persistently elevated blood spot hydroxybutyrylcarnitine concentration when fed, as well as when fasted. Measurement of the activity of L-3-hydroxyacyl-CoA dehydrogenase in cultured skin fibroblasts with acetoacetyl-CoA substrate showed reduced activity. In fibroblast mitochondria, the activity was less than 5% that of controls. Sequencing of the short-chain L-3-hydroxyacyl-CoA dehydrogenase (SCHAD) genomic DNA from the fibroblasts showed a homozygous mutation (C773T) changing proline to leucine at amino acid 258. Analysis of blood from the parents showed they were heterozygous for this mutation. Western blot studies showed undetectable levels of immunoreactive SCHAD protein in the child's fibroblasts. Expression studies showed that the P258L enzyme had no catalytic activity. We conclude that C773T is a disease-causing SCHAD mutation. This is the first defect in fatty acid beta-oxidation that has been associated with hyperinsulinism and raises interesting questions about the ways in which changes in fatty acid and ketone body metabolism modulate insulin secretion by the beta cell. The patient's hyperinsulinism was easily controlled with diazoxide and chlorothiazide.
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Affiliation(s)
- P T Clayton
- London Centre for Paediatric Endocrinology and Metabolism, Biochemistry, Endocrinology and Metabolism Unit, Institute of Child Health, University College London, United Kingdom.
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Ibdah JA, Zhao Y, Viola J, Gibson B, Bennett MJ, Strauss AW. Molecular prenatal diagnosis in families with fetal mitochondrial trifunctional protein mutations. J Pediatr 2001; 138:396-9. [PMID: 11241049 DOI: 10.1067/mpd.2001.111503] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVES To evaluate the feasibility of molecular prenatal diagnosis in families with mitochondrial trifunctional protein (TFP) mutations and prospectively study the effects of fetal genotype on pregnancy outcome. TFP catalyzes the last 3 steps in mitochondrial long-chain fatty acid oxidation. STUDY DESIGN We performed molecular prenatal diagnosis in 9 pregnancies, 8 in 6 families with isolated long-chain 3-hydroxyacyl-coenzyme A dehydrogenase (LCHAD) deficiency and one in a family with complete TFP deficiency. Analyses were performed on chorionic villous samples in 7 pregnancies and on amniocytes in 2. RESULTS Molecular prenatal diagnosis successfully identified the fetal genotype in all 9 pregnancies. Two fetuses were affected, and both pregnancies were terminated by family decision. Two other fetuses had normal genotype and 5 others were heterozygotes. These 7 pregnancies were uncomplicated, and all the offspring are alive and apparently healthy. Genotypes of the aborted fetuses and neonates were confirmed by molecular analysis and enzymatic assays. CONCLUSIONS Molecular prenatal diagnosis is possible and valid in guiding management of pregnancies in families with known TFP defects. Women heterozygous for TFP alpha-subunit mutations who carry fetuses with wild-type or heterozygous genotypes have uncomplicated pregnancies.
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Affiliation(s)
- J A Ibdah
- Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA
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21
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Guertl B, Noehammer C, Hoefler G. Metabolic cardiomyopathies. Int J Exp Pathol 2000; 81:349-72. [PMID: 11298185 PMCID: PMC2517748 DOI: 10.1046/j.1365-2613.2000.00186.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2001] [Accepted: 01/29/2001] [Indexed: 01/27/2023] Open
Abstract
The energy needed by cardiac muscle to maintain proper function is supplied by adenosine Ariphosphate primarily (ATP) production through breakdown of fatty acids. Metabolic cardiomyopathies can be caused by disturbances in metabolism, for example diabetes mellitus, hypertrophy and heart failure or alcoholic cardiomyopathy. Deficiency in enzymes of the mitochondrial beta-oxidation show a varying degree of cardiac manifestation. Aberrations of mitochondrial DNA lead to a wide variety of cardiac disorders, without any obvious correlation between genotype and phenotype. A completely different pathogenetic model comprises cardiac manifestation of systemic metabolic diseases caused by deficiencies of various enzymes in a variety of metabolic pathways. Examples of these disorders are glycogen storage diseases (e.g. glycogenosis type II and III), lysosomal storage diseases (e.g. Niemann-Pick disease, Gaucher disease, I-cell disease, various types of mucopolysaccharidoses, GM1 gangliosidosis, galactosialidosis, carbohydrate-deficient glycoprotein syndromes and Sandhoff's disease). There are some systemic diseases which can also affect the heart, for example triosephosphate isomerase deficiency, hereditary haemochromatosis, CD 36 defect or propionic acidaemia.
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Affiliation(s)
- B Guertl
- Institute of Pathology, University of Graz, Austria.
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22
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Abstract
Acute fatty liver of pregnancy (AFLP) and the syndrome of hemolysis, elevated liver enzymes, and low platelets (the HELLP syndrome) are serious disorders of the third trimester with high maternal and perinatal morbidity and mortality. Over the past decade, several clinical observations have demonstrated an association between these maternal syndromes and a recessively inherited fatty acid oxidation disorder, long chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency. Many women who carried LCHAD-deficient fetuses developed maternal liver disease. Over the past few years, we and others have made significant progress in understanding the molecular basis for this fetal-maternal interaction. Here, we review the studies in literature that led to the establishment of this causative association with particular emphasis on the molecular analysis that delineated the molecular basis of this association. The likely mechanisms for the genotype-phenotype correlations in pediatric LCHAD deficiency and the fetal-maternal interaction are discussed. Finally, the potential implications of our current knowledge for families with pediatric LCHAD deficiency and for women who develop AFLP and HELLP syndrome are discussed.
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Affiliation(s)
- J A Ibdah
- Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA.
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23
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Abstract
Major recent advances in the field of metabolic myopathies have helped delineate the genetic and biochemical basis of these disorders. This progress has also resulted in the development of new diagnostic and therapeutic methodologies. In this second part, we present an updated review of the main nonlysosomal and lysosomal glycogenoses and lipid metabolism defects that manifest with signs of transient or permanent muscle dysfunction. Our intent is to increase the pediatric neurologist's familiarity with these conditions and thus improve decision making in the areas of diagnosis and treatment.
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Affiliation(s)
- B T Darras
- Neuromuscular Program, Department of Neurology, Children's Hospital, Harvard Medical School, Massachusetts, USA
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24
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Abstract
The metabolic myopathies are distinguished by extensive clinical and genetic heterogeneity within and between individual disorders. There are a number of explanations for the variability observed that go beyond single gene mutations or degrees of heteroplasmy in the case of mitochondrial DNA mutations. Some of the contributing factors include protein subunit interactions, tissue-specificity, modifying genetic factors, and environmental triggers. Advances in the molecular analysis of metabolic myopathies during the last decade have not only improved the diagnosis of individual disorders but also helped to characterize the contributing factors that make these disorders so complex.
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Affiliation(s)
- G D Vladutiu
- Associate Professor, Departments of Pediatrics, Neurology, and Pathology, Division of Genetics, School of Medicine and Biomedical Studies, State University of New York at Buffalo, 14209, USA.
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25
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Abstract
Inborn errors of the mitochondrial beta-oxidation of long-chain fatty acids represent an evolving field of inherited metabolic disease. Fatty acid oxidation defects demonstrate an abnormal response to the process of fasting adaptation and affect those tissues that utilize fatty acids as an energy source. These tissues include cardiac and skeletal muscle and liver. Muscle directly uses fatty acids as an energy source whilst hepatic metabolism of fatty acids is mostly directed toward the synthesis of ketone bodies for energy utilization by tissues such as brain. The clinical phenotypes of fatty acid oxidation disorders include disease of one or more of these fatty acid-metabolizing tissues. In this review, we provide an overview of the pathway, discuss the disorders that are well established, and describe recent advances in the field. Currently available diagnostic procedures are critically evaluated.
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Affiliation(s)
- M J Bennett
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas 75235, USA.
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26
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Abstract
Long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency is a rare autosomal recessive disorder with varied expression, from severe hypoglycemia and possible sudden infant death to neurosensory deficits secondary to the acute onset. The neurosensory deficits can include clinical features such as seizure disorders, mental retardation, neuropathy, and retinopathy. The basic defect is the lack of the LCHAD enzyme in the liver, which is necessary for fatty acid metabolism. The condition is usually precipitated by infection and dehydration. A case example of a preschooler with LCHAD deficiency is presented to show the complexity of this disorder and resultant developmental disabilities. Implications for nursing practice, education, and research are discussed in relation to the needs of families with complex, developmental disabilities.
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Affiliation(s)
- M S Faulkner
- Boling Center for Developmental Disabilities, College of Nursing, University of Tennessee, Memphis 38163, USA
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27
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Costa CC, de Almeida IT, Jakobs C, Poll-The BT, Duran M. Dynamic changes of plasma acylcarnitine levels induced by fasting and sunflower oil challenge test in children. Pediatr Res 1999; 46:440-4. [PMID: 10509365 DOI: 10.1203/00006450-199910000-00013] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The dynamic changes of plasma acylcarnitine levels in 1- to 7-y-old children during fasting and after the ingestion of sunflower oil were studied. Glucose, 3-hydroxybutyrate, acetoacetate, FFA, and individual plasma acylcarnitine levels were monitored in both conditions. Fasting experiments lasted for 20 h, and acylcarnitine concentrations were analyzed at 0, 15, and 20 h of fasting. During the fat load, acylcarnitine levels were analyzed at 0, 60, 120, and 180 min. In both tests, a generalized increase of all plasma straight-chain acylcarnitines was observed. Acetylcarnitine contributed the most to the increase of total esterified carnitine. In addition, we demonstrated that the relative increase of each individual acylcarnitine during enhanced fatty acid oxidation is tightly related to its molecular structure and chain length. Fasting as well as the fat load primarily resulted in an increase of unsaturated acylcarnitines. During fasting, C(12:1) and C(14:1) showed a relatively high increase, whereas after the fat load C(16:2) and C(14:2), metabolites of linoleic acid (66% of the fat load), were the main acylcarnitines that increased.
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Affiliation(s)
- C C Costa
- Centro de Metabolismos e Genética, Univ. Lisboa, Portugal
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28
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Ibdah JA, Bennett MJ, Rinaldo P, Zhao Y, Gibson B, Sims HF, Strauss AW. A fetal fatty-acid oxidation disorder as a cause of liver disease in pregnant women. N Engl J Med 1999; 340:1723-31. [PMID: 10352164 DOI: 10.1056/nejm199906033402204] [Citation(s) in RCA: 279] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND Acute fatty liver of pregnancy and the HELLP syndrome (hemolysis, elevated liver-enzyme levels, and a low platelet count) are serious hepatic disorders that may occur during pregnancy in women whose fetuses are later found to have a deficiency of long-chain 3-hydroxyacyl-coenzyme A (CoA) dehydrogenase. This enzyme resides in the mitochondrial trifunctional protein, which also contains the active site of long-chain 2,3-enoyl-CoA hydratase and long-chain 3-ketoacyl-CoA thiolase. We undertook this study to determine the relation between mutations in the trifunctional protein in infants with defects in fatty-acid oxidation and acute liver disease during pregnancy in their mothers. METHODS In 24 children with 3-hydroxyacyl-CoA dehydrogenase deficiency, we used DNA amplification and nucleotide-sequence analyses to identify mutations in the alpha subunit of the trifunctional protein. We then correlated the results with the presence of liver disease during pregnancy in the mothers. RESULTS Nineteen children had a deficiency only of long-chain 3-hydroxyacyl-CoA dehydrogenase and presented with hypoketotic hypoglycemia and fatty liver. In eight children, we identified a homozygous mutation in which glutamic acid at residue 474 was changed to glutamine. Eleven other children were compound heterozygotes, with this mutation in one allele of the alpha-subunit gene and a different mutation in the other allele. While carrying fetuses with the Glu474Gln mutation, 79 percent of the heterozygous mothers had fatty liver of pregnancy or the HELLP syndrome. Five other children, who presented with neonatal dilated cardiomyopathy or progressive neuromyopathy, had complete deficiency of the trifunctional protein (loss of activity of all three enzymes). None had the Glu474Gln mutation, and none of their mothers had liver disease during pregnancy. CONCLUSIONS Women with acute liver disease during pregnancy may have a Glu474Gln mutation in long-chain hydroxyacyl-CoA dehydrogenase. Their infants are at risk for hypoketotic hypoglycemia and fatty liver.
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Affiliation(s)
- J A Ibdah
- Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, USA
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29
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Glasgow JF, Middleton B, Moore R, Gray A, Hill J. The mechanism of inhibition of beta-oxidation by aspirin metabolites in skin fibroblasts from Reye's syndrome patients and controls. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1454:115-25. [PMID: 10354521 DOI: 10.1016/s0925-4439(99)00025-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The effects of aspirin metabolites on beta-oxidation were studied in skin fibroblasts from eight typical Reye's syndrome (RS) patients and controls. RS patients' cells did not differ from controls in rates of palmitate oxidation or in the three component activities of the mitochondrial trifunctional enzyme (MTE), indicating no inherited beta-oxidation defect. Aspirin metabolites salicylate, hydroxyhippurate and gentisate, but not aspirin, directly inhibited palmitate oxidation in control and RS cells. RS cells were significantly more sensitive to inhibition than controls at 0.5 to 5 mM salicylate. Inhibition was concentration-dependent and reversible. Inhibition did not occur in fibroblasts lacking activity of the long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) activity of MTE. Salicylate was therefore inhibiting beta-oxidation at this step. Hydroxyhippurate and salicylate reversibly inhibited HAD activities in extracts of control and RS cells. Studies with pure short-chain HAD and LCHAD (MTE) showed hydroxyhippurate and salicylate were competitive inhibitors of the former but mixed (not competitive) inhibitors of the latter. Both compounds inhibited the combined, three-step, MTE reaction measured in the physiological direction. We conclude that (1) salicylate and hydroxyhippurate decrease beta-oxidation in intact cells by reversible inhibition of LCHAD activity of the MTE, and (2) beta-oxidation in RS cells is inherently more sensitive to inhibition by low concentrations of salicylate than controls.
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Affiliation(s)
- J F Glasgow
- Nuffield Department of Child Health, The Queen's University of Belfast, Royal Belfast Hospital for Sick Children, Belfast BT12 6BA, UK
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30
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Strauss AW, Bennett MJ, Rinaldo P, Sims HF, O'Brien LK, Zhao Y, Gibson B, Ibdah J. Inherited long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency and a fetal-maternal interaction cause maternal liver disease and other pregnancy complications. Semin Perinatol 1999; 23:100-12. [PMID: 10331463 DOI: 10.1016/s0146-0005(99)80044-5] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Fetal-maternal interactions are critical determinants of maternal health during pregnancy and perinatal outcome. This review explores the causative relationship of a fetal disorder of mitochondrial fatty acid oxidation, long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency, and the serious maternal liver diseases of pregnancy-preeclampsia, the HELLP syndrome (hemolysis, elevated liver enzymes, and low platelet counts), and acute fatty liver of pregnancy. Features of the metabolic adaptation necessitated during the fetal-neonatal transition; common phenotypes of pediatric fatty acid oxidation disorders, including neonatal hypoketotic, hypoglycemia and hepatic crisis; and clinical abnormalities of HELLP and acute fatty liver of pregnancy are presented. Evidence that a common mutation in the alpha-subunit (LCHAD) of trifunctional protein, E474Q, is always one of the mutant alleles in fetal isolated LCHAD deficiency associated with these disorders of pregnancy that cause high maternal, fetal, and newborn morbidity and mortality is reviewed. Recommendations for molecular testing for LCHAD deficiency in families with life-threatening maternal liver disease are given.
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Affiliation(s)
- A W Strauss
- Department of Pediatrics, Washington University School of Medicine, St Louis Children's Hospital, MO, USA
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31
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Ventura FV, Costa CG, Struys EA, Ruiter J, Allers P, Ijlst L, Tavares de Almeida I, Duran M, Jakobs C, Wanders RJ. Quantitative acylcarnitine profiling in fibroblasts using [U-13C] palmitic acid: an improved tool for the diagnosis of fatty acid oxidation defects. Clin Chim Acta 1999; 281:1-17. [PMID: 10217622 DOI: 10.1016/s0009-8981(98)00188-0] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A method was developed for the investigation of mitochondrial fatty acid beta-oxidation in cultured fibroblasts. Monolayer cultures were incubated without foetal calf serum with commercially available [U-13C] palmitic acid and L-carnitine for 96 h. The acylcarnitines produced by the cells were extracted from the cell suspension and analysed either by quantitative stable isotope dilution gas chromatography chemical ionization mass spectrometry, or by fast atom bombardment mass spectrometry. Characteristic acylcarnitine profiles were obtained for all the different enzyme deficiencies investigated, with the exception of carnitine palmitoyltransferase II deficiency and carnitine/acylcarnitine carrier deficiency which showed similar patterns. Comparison between this method and the 3H-myristate and 3H-palmitate tritium release assays revealed that the method described here is superior, allowing unequivocal identification of patients.
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Affiliation(s)
- F V Ventura
- Department of Clinical Biochemistry, University Hospital Amsterdam, The Netherlands
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32
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Eaton S, Middleton B, Bartlett K. Control of mitochondrial beta-oxidation: sensitivity of the trifunctional protein to [NAD+]/[NADH] and [acetyl-CoA]/[CoA]. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1429:230-8. [PMID: 9920399 DOI: 10.1016/s0167-4838(98)00246-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Isolated human mitochondrial trifunctional protein was incubated with 2-hexadecenoyl-CoA, CoA and NAD+ and the resultant CoA esters measured. Steady state with respect to the concentrations of the intermediates 3-hydroxyhexadecanoyl-CoA and 3-ketohexadecanoyl-CoA and the rate of formation of the product tetradecanoyl-CoA was reached within 4 min. Flux was greatly enhanced by the addition of Tween 20 (0.2% v/v) which stimulated 3-ketoacyl-CoA thiolase activity by over 7-fold. When 3-ketoacyl-CoA thiolase was not stimulated, 3-hydroxyhexadecanoyl-CoA was the prominent CoA ester accumulated, presumably due to inhibition of 3-hydroxyacyl-CoA dehydrogenase activity by accumulated 3-ketoacyl-CoA, analogous to the inhibition of short-chain 3-hydroxyacyl-CoA dehydrogenase by 3-ketoacyl-CoA. When [NAD+]/[NADH] was varied at a fixed total [NAD++NADH], the overall flux was only inhibited by [NAD+]/[NADH] less than 1. In contrast, when [acetyl-CoA]/[CoA] was varied at a fixed total [CoA], much greater sensitivity was observed.
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Affiliation(s)
- S Eaton
- Sir James Spence Institute of Child Health, Royal Victoria Infirmary, Newcastle-upon-Tyne, UK
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33
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Abstract
Fatty acid oxidation defects can cause recurrent rhabdomyolysis or chronic progressive muscle weakness. Diagnosis is often possible on blood using tandem mass spectrometry or molecular genetic techniques. Riboflavin and carnitine are effective in some cases of multiple acyl-CoA dehydrogenase deficiency and primary carnitine deficiency, respectively. Controlled trials are needed to evaluate other proposed forms of treatment.
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Affiliation(s)
- A A Morris
- Department of Child Health, University of Newcastle upon Tyne, UK
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34
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Ibdah JA, Tein I, Dionisi-Vici C, Bennett MJ, IJlst L, Gibson B, Wanders RJ, Strauss AW. Mild trifunctional protein deficiency is associated with progressive neuropathy and myopathy and suggests a novel genotype-phenotype correlation. J Clin Invest 1998; 102:1193-9. [PMID: 9739053 PMCID: PMC509102 DOI: 10.1172/jci2091] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Human mitochondrial trifunctional protein (TFP) is a heterooctamer of four alpha- and four beta-subunits that catalyzes three steps in the beta-oxidation spiral of long-chain fatty acids. TFP deficiency causes a Reye-like syndrome, cardiomyopathy, or sudden, unexpected death. We delineated the molecular basis for TFP deficiency in two patients with a unique phenotype characterized by chronic progressive polyneuropathy and myopathy without hepatic or cardiac involvement. Single-stranded conformation variance and nucleotide sequencing identified all patient mutations in exon 9 of the alpha-subunit. One patient is homozygous for the T845A mutation that substitutes aspartic acid for valine at residue 246. The second patient is a compound heterozygote for the T914A that substitutes asparagine for isoleucine at residue 269 and a C871T that creates a premature termination at residue 255. Allele-specific oligonucleotide hybridization studies revealed undetectable levels of the mRNA corresponding to the mutant allele carrying the termination codon. This study suggests a novel genotype-phenotype correlation in TFP deficiency; that is, mutations in exon 9 of the alpha-subunit, which encodes a linker domain between the NH2-terminal hydratase and the COOH-terminal 3-hydroxyacyl-CoA dehydrogenase, result in a unique neuromuscular phenotype.
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Affiliation(s)
- J A Ibdah
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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35
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Ventura FV, Ruiter JP, IJlst L, de Almeida IT, Wanders RJ. Lactic acidosis in long-chain fatty acid beta-oxidation disorders. J Inherit Metab Dis 1998; 21:645-54. [PMID: 9762600 DOI: 10.1023/a:1005480516801] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Among the many disorders of fatty acid beta-oxidation known today, the disorders of long-chain fatty acid oxidation are the most severe and life-threatening. One remarkable abnormality, not observed in, for instance, medium-chain acyl-CoA dehydrogenase deficiency, is the moderate to severe lactic acidaemia in long-chain fatty acid beta-oxidation-deficient patients, suggesting that oxidation of pyruvate is also compromised. In order to understand the underlying basis of the lactic acidaemia in these patients, we have studied the formation of L-lactate and pyruvate in cultured skin fibroblasts incubated with D-glucose. All long-chain fatty acid beta-oxidation-deficient cell lines studied were found to show a moderate elevation of lactate when compared with control and medium-chain acyl-CoA dehydrogenase-deficient fibroblasts. Interestingly, differences were found between cells deficient in long-chain 3-hydroxyacyl-CoA dehydrogenase and very-long-chain acyl-CoA dehydrogenase, suggesting that saturated acyl-CoA esters and their 3-hydroxyacyl-CoA derivatives affect pyruvate metabolism differently.
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Affiliation(s)
- F V Ventura
- Department of Clinical Chemistry, Academic Medical Centre, Amsterdam, The Netherlands
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36
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Tyni T, Ekholm E, Pihko H. Pregnancy complications are frequent in long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency. Am J Obstet Gynecol 1998; 178:603-8. [PMID: 9539533 DOI: 10.1016/s0002-9378(98)70446-6] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Preeclampsia-related complications of pregnancy have been detected in carriers of long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency, a recently discovered disorder of mitochondrial fatty acid oxidation. Because no comprehensive study is available, we studied the frequency of pregnancy complications in mothers who had given birth to children with this disorder. STUDY DESIGN Data of all pregnancies of 18 mothers to 28 diagnosed patients with long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency were reviewed retrospectively. From a total 79 pregnancies 16 early abortions were excluded; 63 pregnancies were included, and the fetus was affected in 29. RESULTS One child born prematurely died neonatally but none of the mothers died. Preeclampsia, the syndrome of hemolysis, elevated liver enzymes, and low platelets, and acute fatty liver of pregnancy occurred in 31% and intrahepatic cholestasis in 10% of pregnancies with a long chain 3-hydroxyacyl-coenzyme A-deficient fetus but in none of the pregnancies with a healthy fetus. A total of 40% of affected neonates were born prematurely and 47% had growth restriction, whereas none of the healthy neonates were premature and growth restriction occurred in only 17% (p < 0.01). Prematurity and growth restriction could not be explained solely by the preeclampsia-related conditions. CONCLUSIONS In pregnancies with a long-chain 3-hydroxyacyl-coenzyme A-deficient fetus the frequency of preeclampsia-related conditions is high. The results support the role of fatty acid accumulation in the pathogenesis of preeclampsia. Analysis for the prevalent mutation of this deficiency may be warranted in pregnancies with severe preeclampsia.
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Affiliation(s)
- T Tyni
- Division of Child Neurology, Children's Hospital, University of Helsinki, Finland
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37
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Schrijver-Wieling I, van Rens GH, Wittebol-Post D, Smeitink JA, de Jager JP, de Klerk HB, van Lith GH. Retinal dystrophy in long chain 3-hydroxy-acyl-coA dehydrogenase deficiency. Br J Ophthalmol 1997; 81:291-4. [PMID: 9215057 PMCID: PMC1722172 DOI: 10.1136/bjo.81.4.291] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Long chain 3-hydroxyacyl-CoA-dehydrogenase (LCHAD) is one of the enzymes involved in the breakdown of fatty acids. A deficiency of this enzyme is associated with life threatening episodes of hypoketotic hypoglycaemia during prolonged fasting. Neuropathy and retinopigmentary changes were mentioned in only a few cases. METHODS The case histories of two girls, aged 8 and 15 years, with LCHAD deficiency are reported. RESULTS Both children with LCHAD deficiency exhibited extensive macular pigmentary depositions and a 'salt and pepper' scattering of pigment in their retinas. The patients have decreasing visual acuity. CONCLUSION The early recognition of LCHAD deficiency can increase the life expectancy in these patients through avoiding catabolism and through appropriate diets. Patients tend to be free of symptoms between attacks, however. Testing for the disorder, therefore, should be included in the diagnostic process for children with retinal dystrophy, in particular when other clinical symptoms are known to have occurred.
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Schaefer J, Jackson S, Taroni F, Swift P, Turnbull DM. Characterisation of carnitine palmitoyltransferases in patients with a carnitine palmitoyltransferase deficiency: implications for diagnosis and therapy. J Neurol Neurosurg Psychiatry 1997; 62:169-76. [PMID: 9048718 PMCID: PMC486729 DOI: 10.1136/jnnp.62.2.169] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVES Carnitine palmitoyltransferase (CPT) deficiency is one of the most common defects of mitochondrial fatty acid oxidation. Two different enzymes (CPT-I and CPT-II) are involved. Due to problems in measuring enzyme activity, relatively little is known about the substrate specificity of each of the human enzymes. This is of considerable importance in the treatment of patients. The objectives were to establish a reliable method for the measurement of CPT activity in whole cells, to use this to characterise the substrate specificity of each enzyme, and finally, to determine if medium chain triglycerides would be of benefit in the treatment of deficient patients. METHODS A simple permeabilisation technique was used which allows the measurement of CPT activity in a small amount of cultured skin fibroblasts or peripheral blood cells. Using this technique three patients were identified with CPT deficiency. In two of these patients, one with CPT-I deficiency and one with CPT-II deficiency, a complete substrate specificity profile of the mitochondrial carnitine acyltransferases was established for all saturated even chain acyl-CoA esters. RESULTS For both enzymes the highest CPT activity was with C12-CoA. About 70% of total cellular carnitine octanoyltransferase activity was due to mitochondrial CPT. As CPT is involved in the transport of medium chain fatty acids the metabolic response of a patient with CPT-II deficiency to dietary medium chain triglycerides was assessed. Despite the normal production of ketone bodies there was a significant medium chain dicarboxylic aciduria in the patient, indicating a limited capacity of the CPT independent mitochondrial uptake of medium chain fatty acids. CONCLUSIONS CPT deficiency can easily be diagnosed in permeabilised cultured skin fibroblasts. Both CPT-I and CPT-II are more active with medium chain length substrates than previously assumed. Care should therefore be taken in the treatment of these patients with medium chain triglycerides.
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Affiliation(s)
- J Schaefer
- Department of Neurology, University of Newcastle upon Tyne, UK
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39
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Tyni T, Palotie A, Viinikka L, Valanne L, Salo MK, von Döbeln U, Jackson S, Wanders R, Venizelos N, Pihko H. Long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency with the G1528C mutation: clinical presentation of thirteen patients. J Pediatr 1997; 130:67-76. [PMID: 9003853 DOI: 10.1016/s0022-3476(97)70312-3] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Long-chain 3-hydroxyacyl-coenzyme A (CoA) dehydrogenase is one of three enzyme activities of the mitochondrial trifunctional protein. We report the clinical findings of 13 patients with long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency. At presentation the patients had had hypoglycemia, cardiomyopathy, muscle hypotonia, and hepatomegaly during the first 2 years of life. Seven patients had recurrent metabolic crises, and six patients had a steadily progressive course. Two patients had cholestatic liver disease, which is uncommon in beta-oxidation defects. One patient had peripheral neuropathy, and six patients had retinopathy with focal pigmentary aggregations or retinal hypopigmentation. All patients were homozygous for the common mutation G1528C. However, the enoyl-CoA hydratase and 3-ketoacyl-CoA thiolase activities of the mitochondrial trifunctional protein were variably decreased in skin fibroblasts. Dicarboxylic aciduria was detected in 9 of 10 patients, and most patients had lactic acidosis, increased serum creatine kinase activities, and low serum carnitine concentration. Neuroradiologically there was bilateral periventricular or focal cortical lesions in three patients, and brain atrophy in one. Only one patient, who has had dietary treatment for 9 years, is alive at the age of 14 years; all others died before they were 2 years of age. Recognition of the clinical features of long-chain 3-hydroxyacyl-CoA deficiency is important for the early institution of dietary management, which may alter the otherwise invariably poor prognosis.
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Affiliation(s)
- T Tyni
- Department of Child Neurology, Children's Hospital, University of Helsinki, Finland
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40
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Abstract
The enzymic stages of mammalian mitochondrial beta-oxidation were elucidated some 30-40 years ago. However, the discovery of a membrane-associated multifunctional enzyme of beta-oxidation, a membrane-associated acyl-CoA dehydrogenase and characterization of the carnitine palmitoyl transferase system at the protein and at the genetic level has demonstrated that the enzymes of the system itself are incompletely understood. Deficiencies of many of the enzymes have been recognized as important causes of disease. In addition, the study of these disorders has led to a greater understanding of the molecular mechanism of beta-oxidation and the import, processing and assembly of the beta-oxidation enzymes within the mitochondrion. The tissue-specific regulation, intramitochondrial control and supramolecular organization of the pathway is becoming better understood as sensitive analytical and molecular techniques are applied. This review aims to cover enzymological and organizational aspects of mitochondrial beta-oxidation together with the biochemical aspects of inherited disorders of beta-oxidation and the intrinsic control of beta-oxidation.
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Affiliation(s)
- S Eaton
- Sir James Spence Institute of Child Health, Royal Victoria Infirmary, Newcastle-upon-Tyne, U.K
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41
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Murphy VJ, Mantamadiotis T, Baldwin GS. Gastrin and gastrin receptor antagonists bind to both N- and C-terminal halves of the 78 kDa gastrin-binding protein. Int J Biochem Cell Biol 1996; 28:1233-40. [PMID: 9022282 DOI: 10.1016/s1357-2725(96)00066-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A 78 kDa gastrin-binding protein (GBP) has previously been identified as the target of the anti-proliferative effects of non-selective gastrin/cholecystokinin receptor antagonists on colorectal carcinoma cell lines. The GBP was related in sequence to a family of fatty acid oxidation enzymes possessing enoyl CoA hydratase and 3-hydroxyacyl CoA dehydrogenase activity. This study aims to define the binding site for gastrin and gastrin antagonists in greater detail. The N- and C-terminal halves of the porcine GBP were expressed independently as glutathione S-transferase fusion proteins in E. coli. Affinities of gastrin and gastrin antagonists for the fusion proteins were measured by competition for 125I-[Nle15]-gastrin binding in a covalent cross-linking assay. The N- and C-terminal fusion proteins bound gastrin with affinities of 9.9 +/- 6.1 and 71 +/- 48 microM, respectively (n = 3). These values were 40-fold and 300-fold lower than the affinity of the full-length GBP for gastrin (0.23 +/- 0.15 microM). In contrast, the affinities of the N- and C-terminal halves for the antagonists proglumide (22 +/- 13 and 10 +/- 4 mM, respectively) and benzotript (350 +/- 90 and 400 +/- 160 micro M, respectively) were similar to each other and to the affinities of proglumide and benzotript for the full-length GBP (5.1 +/- 3.6 mM and 200 +/- 120 microM, respectively). It is concluded that proglumide and benzotript bind independently to both the hydratase and dehydrogenase active sites of the GBP, while a single molecule of gastrin may bind simultaneously to both active sites. A model is proposed which is consistent with these data, and which will assist in the development of more potent and selective GBP antagonists.
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Affiliation(s)
- V J Murphy
- Ludwig Institute for Cancer Research, Melbourne Tumour Biology Branch, Royal Melbourne Hospital, Victoria, Australia
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42
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Schaefer J, Jackson S, Dick DJ, Turnbull DM. Trifunctional enzyme deficiency: adult presentation of a usually fatal beta-oxidation defect. Ann Neurol 1996; 40:597-602. [PMID: 8871579 DOI: 10.1002/ana.410400409] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Disorders of mitochondrial fatty acid oxidation are a common cause of exercise-induced rhabdomyolysis and myoglobinuria. We report three adult patients from a family with symptoms of recurrent exercise-induced rhabdomyolysis. This presentation closely resembles adult-type carnitine palmitoyltransferase II deficiency except that these patients had an associated peripheral neuropathy. Investigation of fatty acid oxidation in the patients revealed a deficiency of the mitochondrial trifunctional enzyme of beta-oxidation, a newly described fatty acid oxidation disorder with multiorgan involvement and a usually fatal outcome in early childhood. Our cases therefore represent a new phenotype of the disease, which is characterized by recurrent rhabdomyolysis and peripheral neuropathy, but without involvement of other organs, and which is associated with prolonged survival beyond the fourth decade. A low-fat/high-carbohydrate diet proved beneficial in one of the patients, drastically reducing the frequency of rhabdomyolytic episodes. Our findings suggest that mitochondrial trifunctional enzyme deficiency should be considered in patients with recurrent episodes of myoglobinuria and peripheral neuropathy presenting in later life.
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Affiliation(s)
- J Schaefer
- Department of Neurology, University of Newcastle upon Tyne, UK
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43
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Baldwin GS, Abbott FS, Nau H. Binding of a valproate metabolite to the trifunctional protein of fatty acid oxidation. FEBS Lett 1996; 384:58-60. [PMID: 8797803 DOI: 10.1016/0014-5793(96)00267-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The anti-convulsant drug valproate causes hepatic failure in a small percentage of patients. We now report that the valproate metabolite 2,4-dien-valproate binds (IC50 = 42 microM) to the alpha-subunit of the trifunctional protein responsible for the second and third steps in the mitochondrial beta-oxidation of fatty acids. Binding of valproate itself, or of the metabolites 2-envalproate, 4-en-valproate or 3-hydroxy-4-en-valproate, is considerably weaker. We conclude that valproate-induced hepatotoxicity may be due in part to the reversible binding of the valproate metabolite 2,4-dien-valproate or its CoA ester to the alpha-subunit of the trifunctional protein with consequent inhibition of fatty acid oxidation.
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Affiliation(s)
- G S Baldwin
- Department of Surgery, Austin Hospital, Heidelberg, Victoria, Australia
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44
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Pons R, Roig M, Riudor E, Ribes A, Briones P, Ortigosa L, Baldellou A, Gil-Gibernau J, Olesti M, Navarro C, Wanders RJ. The clinical spectrum of long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency. Pediatr Neurol 1996; 14:236-43. [PMID: 8736409 DOI: 10.1016/0887-8994(96)00021-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Four patients with long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency are presented. Clinical onset in the form of acute encephalopathy occurred between the ages of 9 months and 3 years. The clinical course included recurrent metabolic crises in 4 patients, cardiac involvement and retinopathy in 3, and myopathy in 2. None had signs of peripheral neuropathy. Three patients died and one is currently well. Hypoketotic hypoglycemia with C6-C14 3-hydroxy-dicarboxylic aciduria during metabolic crises associated with decreased plasma carnitine levels was the main biochemical finding. Enzymologic studies disclosed long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency in all patients. Homozygosity for a G to C mutation at position 1528 in the encoding region of the enzyme was found in 2 patients. Histologic and electron microscopic studies of liver biopsy specimens revealed steatosis in 3 patients and mitochondrial abnormalities in 2. Skeletal muscle biopsies disclosed nonspecific degenerative changes in 2 patients and were normal in the remaining 2. Ultrastructural abnormalities in mitochondria were found in 3 patients. A review of the literature combined with the data from our series (total 22 patients) disclosed acute clinical onset in 77% of cases and subacute in 23%. In the combined series, the average age at onset was 11 months, family history was positive in 32% of patients and overall mortality was 50%. We describe the clinical spectrum of this disease and emphasize that, among patients with suspected beta-oxidation defects the finding of pigmentary retinopathy should lead to the suspicion of long-chain 3-hydroxyacyl-coenzyme A-dehydrogenase deficiency.
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Affiliation(s)
- R Pons
- Child Neurology Unit, Vall d'Hebron University Hospital, Barcelona, Spain
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45
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Abrahamsson K, Mellander M, Eriksson BO, Holme E, Jodal U, Jönsson A, Lindstedt S. Transient reduction of human left ventricular mass in carnitine depletion induced by antibiotics containing pivalic acid. BRITISH HEART JOURNAL 1995; 74:656-9. [PMID: 8541173 PMCID: PMC484124 DOI: 10.1136/hrt.74.6.656] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
OBJECTIVE To study the effect of induced carnitine depletion on myocardial structure and function. SUBJECTS AND DESIGN 7 healthy adult volunteers given 1200 mg pivmecillinam per day for 7-8 weeks were studied by echocardiography before and after 7-8 weeks of treatment and a 15 months follow up after the treatment period. SETTING Teaching hospital. MAIN OUTCOME MEASURES Carnitine concentration in serum, urine, and muscle and echocardiographic measurements. RESULTS After 7-8 weeks of treatment the median free serum carnitine concentration was reduced to 7% and the median total muscle carnitine concentration to 46% of the pretreatment levels. The median diastolic interventricular septum thickness decreased by 14% (mean 26%, P = 0.028) and the median left ventricular mass by 10% (mean 20%, P = 0.018). Fifteen months later these dimensions had increased but not completely returned to pretreatment values. CONCLUSIONS Extended treatment with pivalic acid containing antibiotics causes carnitine depletion which may lead to changes in cardiac structure.
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Affiliation(s)
- K Abrahamsson
- Department of Paediatrics, Gothenburg University, Sweden
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46
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Largillière C, Vianey-Saban C, Fontaine M, Bertrand C, Kacet N, Farriaux JP. Mitochondrial very long chain acyl-CoA dehydrogenase deficiency--a new disorder of fatty acid oxidation. Arch Dis Child Fetal Neonatal Ed 1995; 73:F103-5. [PMID: 7583594 PMCID: PMC2528513 DOI: 10.1136/fn.73.2.f103] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Very long chain acyl-CoA dehydrogenase is a newly characterised enzyme in mitochondrial fatty acid oxidation. A girl who presented on the second day of life with a sudden and severe illness due to deficiency of this enzyme is reported. There is evidence that some children (and perhaps all) originally diagnosed with a deficiency of long-chain acyl-CoA dehydrogenase, in fact, have a defect involving very long chain acyl-CoA dehydrogenase.
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Affiliation(s)
- C Largillière
- Hopital Huriez, Lille, France, Department of Paediatrics, France
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47
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Brackett JC, Sims HF, Rinaldo P, Shapiro S, Powell CK, Bennett MJ, Strauss AW. Two alpha subunit donor splice site mutations cause human trifunctional protein deficiency. J Clin Invest 1995; 95:2076-82. [PMID: 7738175 PMCID: PMC295799 DOI: 10.1172/jci117894] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Human trifunctional protein catalyzes three steps in mitochondrial beta-oxidation of fatty acids, including the long chain 3-hydroxyacyl-CoA dehydrogenase step. Deficiency of this heterocomplex, which contains 4 alpha and 4 beta subunits, causes sudden unexplained infant death, a Reye-like syndrome, cardiomyopathy, or skeletal myopathy. We determined the molecular basis of this deficiency in a patient with neonatal presentation and later sudden death using reverse transcription and PCR amplification of his alpha subunit mRNA. We demonstrated a universal deletion of exon 3 (71 bp) in his mRNA. This deletion causes a frameshift and very early premature termination. Amplification of genomic DNA demonstrated that the patient was a compound heterozygote with two different mutations in the 5' donor splice site following exon 3: a paternally inherited G to A transversion at the invariant position +1 and a maternally inherited A to G mutation at position +3. Both allelic mutations apparently cause exon 3 skipping, resulting in undetectable levels of alpha subunit protein, and complete loss of trifunctional protein. This is the initial molecular characterization of trifunctional protein deficiency.
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Affiliation(s)
- J C Brackett
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
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48
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Tein I, Donner EJ, Hale DE, Murphy EG. Clinical and neurophysiologic response of myopathy and neuropathy in long-chain L-3-hydroxyacyl-CoA dehydrogenase deficiency to oral prednisone. Pediatr Neurol 1995; 12:68-76. [PMID: 7748366 DOI: 10.1016/0887-8994(94)00109-f] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The purpose of this study was to evaluate the clinical and neurophysiologic responses to oral prednisone therapy in a boy with enzymatically confirmed long-chain L-3-hydroxyacyl-CoA dehydrogenase deficiency in biopsied muscle and cultured skin fibroblasts. This boy presented with progressive limb girdle myopathy, recurrent myoglobinuria, peripheral sensorimotor axonopathy, and intraventricular conduction delays. Prior to prednisone therapy, at age 8 years, he exhibited marked distal weakness greater than proximal weakness with a waddling and high-steppage gait, Gowers' maneuver (10 s to rise from the floor), fatigue after 3-20 yards of walking and the ability to climb only 2 stairs. Serum levels of creatine kinase rose from 34 to 4,124 U/L following mild exertion. Nerve conduction studies revealed progressive axonopathy with secondary demyelination. Four weeks after initiation of oral prednisone (0.75 mg/kg/day) therapy, there was approximately a 100% increase in power and endurance. He was able to walk at least 100 yards before tiring, could rise from sitting on the floor in 3-4 s, and was able to climb 20 steps in 30 s. There was concurrent improvement in nerve conduction studies. Prednisone was gradually withdrawn over the next 4 months to 0.19 mg/kg/day; lower doses of 0.08 mg/kg/day resulted in a marked deterioration in power to the prior state. Although 0.19 mg/kg/day did not maintain the peak power achieved at 0.75 mg/kg/day, it provided adequate baseline power and endurance. It is concluded that there was a significant clinical and neurophysiologic response to prednisone at a dosage > or = 0.16 mg/kg/day. Prednisone may stabilize muscle and neuronal plasma membranes, as well as the fatty acid oxidation enzyme complex in the mitochondrial membrane.
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Affiliation(s)
- I Tein
- Division of Neurology, Hospital for Sick Children, Toronto, Ontario, Canada
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49
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Abstract
The oxidation of long-chain fatty acids requires a series of enzymes which are located in or on the mitochondrial membranes. These include carnitine palmitoyltransferases I and II, a carnitine-acylcarnitine translocase and, newly discovered, very long-chain acyl-CoA dehydrogenase and the mitochondrial trifunctional protein. These last two chain-shorten acyl-CoA esters to the point where they can be transferred to the more soluble medium- and short-chain-specific enzymes within the mitochondrial matrix. The disorders of long-chain fatty acid oxidation show a rather similar range of clinical and biochemical features, though with different emphasis in the different conditions. Patients with severe defects usually present early with acute attacks of hypoketotic hypoglycaemia and impaired liver function, or with cardiomyopathy or cardiac arrhythmia. In milder variants, skeletal myopathy with intermittent myoglobinuria develops later in life. 3-Hydroxyacyl-CoA dehydrogenase deficiency is unusual in producing peripheral neuropathy and retinitis pigmentosa. Treatment is based on the avoidance of fasting and replacement of normal dietary fat by medium-chain triglyceride, the medium-chain fatty acids entering the mitochondria in a carnitine-independent manner and bypassing the long-chain part of the spiral. Diagnosis must ultimately be based on direct assay of the enzyme involved, but preliminary indicators may come from determination of carnitine and intermediate metabolites in plasma, urinary organic acid profiling, and radioisotopic screening assays with lymphocytes or cultured fibroblasts.
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Affiliation(s)
- R J Pollitt
- Neonatal Screening Laboratory, Children's Hospital, Sheffield, UK
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50
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Abstract
Organic acid analysis is a powerful technique in the diagnosis of inborn errors of metabolism. Since the development of the technique over twenty-five years ago, it has evolved into a sophisticated and powerful method and is an essential tool in the diagnosis of the organic acidurias. The chemistry and biochemistry of organic acids, as well as sample preparation, instrumentation, and many aspects of the more commonly used methods for the analysis of these compounds, are reviewed. The biochemical and clinical characteristics of each of the primary organic acidurias are described. In addition, the various noninherited causes of secondary organic acidurias that lead to the excretion of abnormal organic acids are also described, and ways of differentiating primary from secondary causes are discussed.
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Affiliation(s)
- D C Lehotay
- Department of Clinical Biochemistry, Hospital for Sick Children, University of Toronto, Ontario, Canada
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