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[Expert consensus on the diagnosis and treatment of neonatal hyperammonemia]. ZHONGGUO DANG DAI ER KE ZA ZHI = CHINESE JOURNAL OF CONTEMPORARY PEDIATRICS 2023; 25:437-447. [PMID: 37272168 PMCID: PMC10247199 DOI: 10.7499/j.issn.1008-8830.2302140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 04/07/2023] [Indexed: 06/06/2023]
Abstract
Neonatal hyperammonemia is a disorder of ammonia metabolism that occurs in the neonatal period. It is a clinical syndrome characterized by abnormal accumulation of ammonia in the blood and dysfunction of the central nervous system. Due to its low incidence and lack of specificity in clinical manifestations, it is easy to cause misdiagnosis and missed diagnosis. In order to further standardize the diagnosis and treatment of neonatal hyperammonemia, the Youth Commission, Subspecialty Group of Neonatology, Society of Pediatrics, Chinese Medical Association formulated the expert consensus based on clinical evidence in China and overseas and combined with clinical practice experience,and put forward 18 recommendations for the diagnosis and treatment of neonatal hyperaminemia.
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2
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Weiss KJ, Berger U, Haider M, Wagner M, Märtner EMC, Regenauer-Vandewiele S, Lotz-Havla A, Schuhmann E, Röschinger W, Maier EM. Free carnitine concentrations and biochemical parameters in medium-chain acyl-CoA dehydrogenase deficiency: Genotype-phenotype correlation. Clin Genet 2023; 103:644-654. [PMID: 36840705 DOI: 10.1111/cge.14316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 02/18/2023] [Accepted: 02/20/2023] [Indexed: 02/26/2023]
Abstract
Biallelic variants in the ACADM gene cause medium-chain acyl-CoA dehydrogenase deficiency (MCADD). This study reports on differences in the occurrence of secondary free carnitine (C0) deficiency and different biochemical phenotypes related to genotype and age in 109 MCADD patients followed-up at a single tertiary care center during 22 years. C0 deficiency occurred earlier and more frequently in c.985A>G homozygotes (genotype A) compared to c.985A>G compound heterozygotes (genotype B) and individuals carrying variants other than c.985A>G and c.199C>T (genotype D) (median age 4.2 vs. 6.6 years; p < 0.001). No patient carrying c.199C>T (genotype C) developed C0 deficiency. A daily dosage of 20-40 mg/kg carnitine was sufficient to maintain normal C0 concentrations. Compared to genotype A as reference group, octanoylcarnitine (C8) was significantly lower in genotypes B and C, whereas C0 was significantly higher by 8.28 μmol/L in genotype C (p < 0.05). In conclusion, C0 deficiency is mainly found in patients with pathogenic genotypes associated with high concentrations of presumably toxic acylcarnitines, while individuals carrying the variant c.199C>T are spared and show consistently mild biochemical phenotypes into adulthood. Low-dose carnitine supplementation maintains normal C0 concentrations. However, future studies need to evaluate clinical benefits on acute and chronic manifestations of MCADD.
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Affiliation(s)
- Katharina J Weiss
- Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany
| | - Ursula Berger
- Institute for Medical Information Processing, Biometry and Epidemiology, Ludwig-Maximilians-University, Munich, Germany
| | - Maliha Haider
- Institute for Medical Information Processing, Biometry and Epidemiology, Ludwig-Maximilians-University, Munich, Germany
| | - Matias Wagner
- Institute of Human Genetics, School of Medicine, Technical University, Munich, Germany.,Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
| | | | | | - Amelie Lotz-Havla
- Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany
| | | | - Wulf Röschinger
- Labor Becker MVZ GbR, Newborn Screening Unit, Munich, Germany
| | - Esther M Maier
- Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany
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3
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Tan YY, Fong WYN, Chan CJ, Chandran S. Do renal and cardiac malformations in the fetus signal carnitine palmitoyltransferase II deficiency? A rare lethal fatty acid oxidation defect. BMJ Case Rep 2022; 15:e251321. [PMID: 36535739 PMCID: PMC9764616 DOI: 10.1136/bcr-2022-251321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The neonatal form of carnitine palmitoyltransferase II (CPT II) deficiency is a rare lethal inherited disorder of fatty acid oxidation. Carnitine essentially transfers long-chain fatty acids across the mitochondrial membranes for β-oxidation, where CPT II plays a key role. CPT II deficiency phenotypical forms include lethal neonatal, severe infantile and myopathic forms. We present a term small-for-gestational-age neonate with hypoglycaemia, seizures, refractory cardiac arrhythmias and intracranial haemorrhage. Plasma acylcarnitine profile and the genetic study confirmed CPT II deficiency. Additionally, likely pathogenic variants in the SLC22A5 gene point to primary carnitine deficiency. Antenatal findings of polycystic kidney disease and cardiomegaly were confirmed postnatally. All supportive measures, including extracorporeal life support, failed to improve the clinical course, and the baby succumbed. Major renal, cerebral and cardiac anomalies were reported with CPT II deficiency. In our case, fetal polycystic nephromegaly and cardiomegaly with parental consanguinity should have signalled the possibility of this disorder.
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Affiliation(s)
- Yee Yin Tan
- Department of Neonatology, KK Women's and Children's Hospital, Singapore
| | - Wen Yan Nikki Fong
- Genetic Services, Department of Paediatrics, KK Women's and Children's Hospital, Singapore
| | - Charmaine Jiahui Chan
- Department of Paediatric Subspecialities, KK Women's and Children's Hospital, Singapore
- Paediatric Academic Clinical Programme, Lee Kong Chian School of Medicine, Singapore
- Paediatric Academic Clinical Programme, Duke NUS Medical School, Singapore
- Paediatric Academic Clinical Programme, Yong Loo Lin School of Medicine, Singapore
| | - Suresh Chandran
- Department of Neonatology, KK Women's and Children's Hospital, Singapore
- Paediatric Academic Clinical Programme, Lee Kong Chian School of Medicine, Singapore
- Paediatric Academic Clinical Programme, Duke NUS Medical School, Singapore
- Paediatric Academic Clinical Programme, Yong Loo Lin School of Medicine, Singapore
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4
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L-Carnitine and Acylcarnitines: Mitochondrial Biomarkers for Precision Medicine. Metabolites 2021; 11:metabo11010051. [PMID: 33466750 PMCID: PMC7829830 DOI: 10.3390/metabo11010051] [Citation(s) in RCA: 135] [Impact Index Per Article: 45.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/08/2021] [Accepted: 01/11/2021] [Indexed: 12/11/2022] Open
Abstract
Biomarker discovery and implementation are at the forefront of the precision medicine movement. Modern advances in the field of metabolomics afford the opportunity to readily identify new metabolite biomarkers across a wide array of disciplines. Many of the metabolites are derived from or directly reflective of mitochondrial metabolism. L-carnitine and acylcarnitines are established mitochondrial biomarkers used to screen neonates for a series of genetic disorders affecting fatty acid oxidation, known as the inborn errors of metabolism. However, L-carnitine and acylcarnitines are not routinely measured beyond this screening, despite the growing evidence that shows their clinical utility outside of these disorders. Measurements of the carnitine pool have been used to identify the disease and prognosticate mortality among disorders such as diabetes, sepsis, cancer, and heart failure, as well as identify subjects experiencing adverse drug reactions from various medications like valproic acid, clofazimine, zidovudine, cisplatin, propofol, and cyclosporine. The aim of this review is to collect and interpret the literature evidence supporting the clinical biomarker application of L-carnitine and acylcarnitines. Further study of these metabolites could ultimately provide mechanistic insights that guide therapeutic decisions and elucidate new pharmacologic targets.
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5
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Verkerk AO, Knottnerus SJG, Portero V, Bleeker JC, Ferdinandusse S, Guan K, IJlst L, Visser G, Wanders RJA, Wijburg FA, Bezzina CR, Mengarelli I, Houtkooper RH. Electrophysiological Abnormalities in VLCAD Deficient hiPSC-Cardiomyocytes Do not Improve with Carnitine Supplementation. Front Pharmacol 2021; 11:616834. [PMID: 33597881 PMCID: PMC7883678 DOI: 10.3389/fphar.2020.616834] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 11/24/2020] [Indexed: 12/13/2022] Open
Abstract
Patients with a deficiency in very long-chain acyl-CoA dehydrogenase (VLCAD), an enzyme that is involved in the mitochondrial beta-oxidation of long-chain fatty acids, are at risk for developing cardiac arrhythmias. In human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs), VLCAD deficiency (VLCADD) results in a series of abnormalities, including: 1) accumulation of long-chain acylcarnitines, 2) action potential shortening, 3) higher systolic and diastolic intracellular Ca2+ concentrations, and 4) development of delayed afterdepolarizations. In the fatty acid oxidation process, carnitine is required for bidirectional transport of acyl groups across the mitochondrial membrane. Supplementation has been suggested as potential therapeutic approach in VLCADD, but its benefits are debated. Here, we studied the effects of carnitine supplementation on the long-chain acylcarnitine levels and performed electrophysiological analyses in VLCADD patient-derived hiPSC-CMs with a ACADVL gene mutation (p.Val283Ala/p.Glu381del). Under standard culture conditions, VLCADD hiPSC-CMs showed high concentrations of long-chain acylcarnitines, short action potentials, and high delayed afterdepolarizations occurrence. Incubation of the hiPSC-CMs with 400 µM L-carnitine for 48 h led to increased long-chain acylcarnitine levels both in medium and cells. In addition, carnitine supplementation neither restored abnormal action potential parameters nor the increased occurrence of delayed afterdepolarizations in VLCADD hiPSC-CMs. We conclude that long-chain acylcarnitine accumulation and electrophysiological abnormalities in VLCADD hiPSC-CMs are not normalized by carnitine supplementation, indicating that this treatment is unlikely to be beneficial against cardiac arrhythmias in VLCADD patients.
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Affiliation(s)
- Arie O Verkerk
- Department of Clinical and Experimental Cardiology, Heart Center, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands.,Department of Medical Biology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Suzan J G Knottnerus
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Amsterdam Gastroenterology and Metabolism, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands.,Department of Pediatric Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, Netherlands
| | - Vincent Portero
- Department of Clinical and Experimental Cardiology, Heart Center, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Jeannette C Bleeker
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Amsterdam Gastroenterology and Metabolism, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands.,Department of Pediatric Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, Netherlands
| | - Sacha Ferdinandusse
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Amsterdam Gastroenterology and Metabolism, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
| | - Kaomei Guan
- Institute of Pharmacology and Toxicology, Technische Universität Dresden, Dresden, Germany
| | - Lodewijk IJlst
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Amsterdam Gastroenterology and Metabolism, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
| | - Gepke Visser
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Amsterdam Gastroenterology and Metabolism, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands.,Department of Pediatric Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, Netherlands
| | - Ronald J A Wanders
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Amsterdam Gastroenterology and Metabolism, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
| | - Frits A Wijburg
- Department of Pediatric Metabolic Diseases, Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Connie R Bezzina
- Department of Clinical and Experimental Cardiology, Heart Center, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Isabella Mengarelli
- Department of Clinical and Experimental Cardiology, Heart Center, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Riekelt H Houtkooper
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Amsterdam Gastroenterology and Metabolism, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
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6
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Bene J, Szabo A, Komlósi K, Melegh B. Mass Spectrometric Analysis of L-carnitine and its Esters: Potential Biomarkers of Disturbances in Carnitine Homeostasis. Curr Mol Med 2020; 20:336-354. [PMID: 31729298 PMCID: PMC7231908 DOI: 10.2174/1566524019666191113120828] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 10/31/2019] [Accepted: 11/01/2019] [Indexed: 12/31/2022]
Abstract
PURPOSE After a golden age of classic carnitine research three decades ago, the spread of mass spectrometry opened new perspectives and a much better understanding of the carnitine system is available nowadays. In the classic period, several human and animal studies were focused on various distinct physiological functions of this molecule and these revealed different aspects of carnitine homeostasis in normal and pathological conditions. Initially, the laboratory analyses were based on the classic or radioenzymatic assays, enabling only the determination of free and total carnitine levels and calculation of total carnitine esters' amount without any information on the composition of the acyl groups. The introduction of mass spectrometry allowed the measurement of free carnitine along with the specific and sensitive determination of different carnitine esters. Beyond basic research, mass spectrometry study of carnitine esters was introduced into the newborn screening program because of being capable to detect more than 30 metabolic disorders simultaneously. Furthermore, mass spectrometry measurements were performed to investigate different disease states affecting carnitine homeostasis, such as diabetes, chronic renal failure, celiac disease, cardiovascular diseases, autism spectrum disorder or inflammatory bowel diseases. RESULTS This article will review the recent advances in the field of carnitine research with respect to mass spectrometric analyses of acyl-carnitines in normal and various pathological states. CONCLUSION The growing number of publications using mass spectrometry as a tool to investigate normal physiological conditions or reveal potential biomarkers of primary and secondary carnitine deficiencies shows that this tool brought a new perspective to carnitine research.
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Affiliation(s)
- Judit Bene
- Department of Medical Genetics, Clinical Center, Medical School, University of Pécs, Pécs, Hungary
- Szentágothai Research Centre, University of Pécs, Pécs, Hungary
| | - Andras Szabo
- Department of Medical Genetics, Clinical Center, Medical School, University of Pécs, Pécs, Hungary
- Szentágothai Research Centre, University of Pécs, Pécs, Hungary
| | - Katalin Komlósi
- Department of Medical Genetics, Clinical Center, Medical School, University of Pécs, Pécs, Hungary
| | - Bela Melegh
- Department of Medical Genetics, Clinical Center, Medical School, University of Pécs, Pécs, Hungary
- Szentágothai Research Centre, University of Pécs, Pécs, Hungary
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7
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Almannai M, Alfadhel M, El-Hattab AW. Carnitine Inborn Errors of Metabolism. Molecules 2019; 24:molecules24183251. [PMID: 31500110 PMCID: PMC6766900 DOI: 10.3390/molecules24183251] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 08/29/2019] [Accepted: 09/04/2019] [Indexed: 12/21/2022] Open
Abstract
Carnitine plays essential roles in intermediary metabolism. In non-vegetarians, most of carnitine sources (~75%) are obtained from diet whereas endogenous synthesis accounts for around 25%. Renal carnitine reabsorption along with dietary intake and endogenous production maintain carnitine homeostasis. The precursors for carnitine biosynthesis are lysine and methionine. The biosynthetic pathway involves four enzymes: 6-N-trimethyllysine dioxygenase (TMLD), 3-hydroxy-6-N-trimethyllysine aldolase (HTMLA), 4-N-trimethylaminobutyraldehyde dehydrogenase (TMABADH), and γ-butyrobetaine dioxygenase (BBD). OCTN2 (organic cation/carnitine transporter novel type 2) transports carnitine into the cells. One of the major functions of carnitine is shuttling long-chain fatty acids across the mitochondrial membrane from the cytosol into the mitochondrial matrix for β-oxidation. This transport is achieved by mitochondrial carnitine–acylcarnitine cycle, which consists of three enzymes: carnitine palmitoyltransferase I (CPT I), carnitine-acylcarnitine translocase (CACT), and carnitine palmitoyltransferase II (CPT II). Carnitine inborn errors of metabolism could result from defects in carnitine biosynthesis, carnitine transport, or mitochondrial carnitine–acylcarnitine cycle. The presentation of these disorders is variable but common findings include hypoketotic hypoglycemia, cardio(myopathy), and liver disease. In this review, the metabolism and homeostasis of carnitine are discussed. Then we present details of different inborn errors of carnitine metabolism, including clinical presentation, diagnosis, and treatment options. At the end, we discuss some of the causes of secondary carnitine deficiency.
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Affiliation(s)
- Mohammed Almannai
- Section of Medical Genetics, Children's Hospital, King Fahad Medical City, Riyadh 11525, Saudi Arabia.
| | - Majid Alfadhel
- Division of Genetics, Department of Pediatrics, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (MNGHA), Riyadh 11426, Saudi Arabia.
- King Abdullah International Medical Research Center (KAIMRC), Riyadh 11426, Saudi Arabia.
- College of Medicine, King Saud Bin Abdulaziz University for Health Sciences, Riyadh 11426, Saudi Arabia.
| | - Ayman W El-Hattab
- Department of Clinical Sciences, College of Medicine, University of Sharjah, Sharjah 27272, UAE.
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8
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Vallance HD, Koochin A, Branov J, Rosen-Heath A, Bosdet T, Wang Z, Hazen SL, Horvath G. Marked elevation in plasma trimethylamine-N-oxide (TMAO) in patients with mitochondrial disorders treated with oral l-carnitine. Mol Genet Metab Rep 2018; 15:130-133. [PMID: 30023305 PMCID: PMC6047224 DOI: 10.1016/j.ymgmr.2018.04.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 04/20/2018] [Accepted: 04/20/2018] [Indexed: 11/26/2022] Open
Abstract
Oral supplementation with l-carnitine is a common therapeutic modality for mitochondrial disorders despite limited evidence of efficacy. Recently, a number of studies have demonstrated that a gut microbiota-dependent metabolite of l-carnitine, trimethylamine oxide (TMAO), is an independent and dose-dependent risk factor for cardiovascular disease (CVD). Given the limited data demonstrating efficacy with oral l-carnitine therapy and the newly raised questions of potential harm, we assessed plasma TMAO levels in patients with mitochondrial disease with and without oral l-carnitine supplementation. Nine subjects were recruited and completed the study. Eight out of 9 subjects at baseline had plasma TMAO concentrations <97.5th percentile (<15.5 μM). One subject with stage 3 renal disease, had marked elevation in plasma TMAO (pre 33.98 μm versus post 101.6 μm). Following at least 3 months of l-carnitine supplementation (1000 mg per day), plasma TMAO levels were markedly increased in 7out of 9 subjects; overall, plasma TMAO significantly increased 11.8-fold (p < 0.001) from a baseline median level of 3.54 μm (interquartile range (IQR) 2.55–8.72) to 43.26 (IQR 23.99–56.04) post supplementation. The results of this study demonstrate that chronic oral l-carnitine supplementation markedly increases plasma TMAO levels in subjects with mitochondrial disorders. Further studies to evaluate both the efficacy and long term safety of oral l-carnitine supplementation for the treatment of mitochondrial disorders are warranted.
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Affiliation(s)
- H D Vallance
- Biochemical Genetics laboratory, Department of Pathology and Laboratory Medicine, BC Children's Hospital, 4480 Oak Street, Vancouver, BC, Canada
| | - A Koochin
- Adult Metabolic Diseases Clinic, Level 4 - 2775 Laurel Street, V5Z 1M0 Vancouver, BC, Canada
| | - J Branov
- Adult Metabolic Diseases Clinic, Level 4 - 2775 Laurel Street, V5Z 1M0 Vancouver, BC, Canada
| | - A Rosen-Heath
- Adult Metabolic Diseases Clinic, Level 4 - 2775 Laurel Street, V5Z 1M0 Vancouver, BC, Canada
| | - T Bosdet
- Adult Metabolic Diseases Clinic, Level 4 - 2775 Laurel Street, V5Z 1M0 Vancouver, BC, Canada
| | - Z Wang
- Department of Cellular and Molecular Medicine, Center for Microbiome & Human Health, Lerner Research Institute, Cleveland Clinic, OH 44195, USA
| | - S L Hazen
- Department of Cellular and Molecular Medicine, Center for Microbiome & Human Health, Lerner Research Institute, Cleveland Clinic, OH 44195, USA.,Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, OH 44195,USA
| | - G Horvath
- Adult Metabolic Diseases Clinic, Level 4 - 2775 Laurel Street, V5Z 1M0 Vancouver, BC, Canada
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Knottnerus SJG, Bleeker JC, Wüst RCI, Ferdinandusse S, IJlst L, Wijburg FA, Wanders RJA, Visser G, Houtkooper RH. Disorders of mitochondrial long-chain fatty acid oxidation and the carnitine shuttle. Rev Endocr Metab Disord 2018; 19:93-106. [PMID: 29926323 PMCID: PMC6208583 DOI: 10.1007/s11154-018-9448-1] [Citation(s) in RCA: 178] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Mitochondrial fatty acid oxidation is an essential pathway for energy production, especially during prolonged fasting and sub-maximal exercise. Long-chain fatty acids are the most abundant fatty acids in the human diet and in body stores, and more than 15 enzymes are involved in long-chain fatty acid oxidation. Pathogenic mutations in genes encoding these enzymes result in a long-chain fatty acid oxidation disorder in which the energy homeostasis is compromised and long-chain acylcarnitines accumulate. Symptoms arise or exacerbate during catabolic situations, such as fasting, illness and (endurance) exercise. The clinical spectrum is very heterogeneous, ranging from hypoketotic hypoglycemia, liver dysfunction, rhabdomyolysis, cardiomyopathy and early demise. With the introduction of several of the long-chain fatty acid oxidation disorders (lcFAOD) in newborn screening panels, also asymptomatic individuals with a lcFAOD are identified. However, despite early diagnosis and dietary therapy, a significant number of patients still develop symptoms emphasizing the need for individualized treatment strategies. This review aims to function as a comprehensive reference for clinical and laboratory findings for clinicians who are confronted with pediatric and adult patients with a possible diagnosis of a lcFAOD.
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Affiliation(s)
- Suzan J G Knottnerus
- Dutch Fatty Acid Oxidation Expertise Center, Department of Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Lundlaan 6, 3584, EA, Utrecht, The Netherlands
- Dutch Fatty Acid Oxidation Expertise Center, Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands
| | - Jeannette C Bleeker
- Dutch Fatty Acid Oxidation Expertise Center, Department of Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Lundlaan 6, 3584, EA, Utrecht, The Netherlands
- Dutch Fatty Acid Oxidation Expertise Center, Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands
| | - Rob C I Wüst
- Dutch Fatty Acid Oxidation Expertise Center, Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands
| | - Sacha Ferdinandusse
- Dutch Fatty Acid Oxidation Expertise Center, Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands
| | - Lodewijk IJlst
- Dutch Fatty Acid Oxidation Expertise Center, Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands
| | - Frits A Wijburg
- Dutch Fatty Acid Oxidation Expertise Center, Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands
| | - Ronald J A Wanders
- Dutch Fatty Acid Oxidation Expertise Center, Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands
| | - Gepke Visser
- Dutch Fatty Acid Oxidation Expertise Center, Department of Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Lundlaan 6, 3584, EA, Utrecht, The Netherlands.
- Dutch Fatty Acid Oxidation Expertise Center, Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands.
| | - Riekelt H Houtkooper
- Dutch Fatty Acid Oxidation Expertise Center, Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands.
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10
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Advances in the Understanding and Treatment of Mitochondrial Fatty Acid Oxidation Disorders. CURRENT GENETIC MEDICINE REPORTS 2017; 5:132-142. [PMID: 29177110 DOI: 10.1007/s40142-017-0125-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Purpose of review This review focuses on advances made in the past three years with regards to understanding the mitochondrial fatty acid oxidation (FAO) pathway, the pathophysiological ramifications of genetic lesions in FAO enzymes, and emerging therapies for FAO disorders. Recent findings FAO has now been recognized to play a key energetic role in pulmonary surfactant synthesis, T-cell differentiation and memory, and the response of the proximal tubule to kidney injury. Patients with FAO disorders may face defects in these cellular systems as they age. Aspirin, statins, and nutritional supplements modulate the rate of FAO under normal conditions and could be risk factors for triggering symptoms in patients with FAO disorders. Patients have been identified with mutations in the ACAD9 and ECHS1 genes, which may represent new FAO disorders. New interventions for long-chain FAODs are in clinical trials. Finally, post-translational modifications that regulate fatty acid oxidation protein activities have been characterized that represent important new therapeutic targets. Summary Recent research has led to a deeper understanding of FAO. New therapeutic avenues are being pursued that may ultimately cause a paradigm shift for patient care.
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11
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Chronic Oral L-Carnitine Supplementation Drives Marked Plasma TMAO Elevations in Patients with Organic Acidemias Despite Dietary Meat Restrictions. JIMD Rep 2016; 30:39-44. [PMID: 26936850 DOI: 10.1007/8904_2016_539] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 01/20/2016] [Accepted: 01/21/2016] [Indexed: 12/24/2022] Open
Abstract
Recent studies have implicated trimethylamine N-oxide (TMAO) in atherosclerosis, raising concern about L-carnitine, a common supplement for patients with inborn errors of metabolism (IEMs) and a TMAO precursor metabolized, in part, by intestinal microbes. Dietary meat restriction attenuates carnitine-to-TMAO conversion, suggesting that TMAO production may not occur in meat-restricted individuals taking supplemental L-carnitine, but this has not been tested. Here, we mine a metabolomic dataset to assess TMAO levels in patients with diverse IEMs, including organic acidemias. These data were correlated with clinical information and confirmed using a quantitative TMAO assay. Marked plasma TMAO elevations were detected in patients treated with supplemental L-carnitine, including those on a meat-free diet. On average, patients with an organic acidemia had ~45-fold elevated [TMAO], as compared to the reference population. This effect was mitigated by metronidazole therapy lasting 7 days each month. Collectively, our data show that TMAO production occurs at high levels in patients with IEMs receiving oral L-carnitine. Further studies are needed to determine the long-term safety and efficacy of chronic oral L-carnitine supplementation and whether suppression or circumvention of intestinal bacteria may improve L-carnitine therapy.
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Otsubo C, Bharathi S, Uppala R, Ilkayeva OR, Wang D, McHugh K, Zou Y, Wang J, Alcorn JF, Zuo YY, Hirschey MD, Goetzman ES. Long-chain Acylcarnitines Reduce Lung Function by Inhibiting Pulmonary Surfactant. J Biol Chem 2015; 290:23897-904. [PMID: 26240137 DOI: 10.1074/jbc.m115.655837] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Indexed: 11/06/2022] Open
Abstract
The role of mitochondrial energy metabolism in maintaining lung function is not understood. We previously observed reduced lung function in mice lacking the fatty acid oxidation enzyme long-chain acyl-CoA dehydrogenase (LCAD). Here, we demonstrate that long-chain acylcarnitines, a class of lipids secreted by mitochondria when metabolism is inhibited, accumulate at the air-fluid interface in LCAD(-/-) lungs. Acylcarnitine accumulation is exacerbated by stress such as influenza infection or by dietary supplementation with l-carnitine. Long-chain acylcarnitines co-localize with pulmonary surfactant, a unique film of phospholipids and proteins that reduces surface tension and prevents alveolar collapse during breathing. In vitro, the long-chain species palmitoylcarnitine directly inhibits the surface adsorption of pulmonary surfactant as well as its ability to reduce surface tension. Treatment of LCAD(-/-) mice with mildronate, a drug that inhibits carnitine synthesis, eliminates acylcarnitines and improves lung function. Finally, acylcarnitines are detectable in normal human lavage fluid. Thus, long-chain acylcarnitines may represent a risk factor for lung injury in humans with dysfunctional fatty acid oxidation.
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Affiliation(s)
- Chikara Otsubo
- From the Department of Pediatrics, University of Pittsburgh School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania 15224
| | - Sivakama Bharathi
- From the Department of Pediatrics, University of Pittsburgh School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania 15224
| | - Radha Uppala
- From the Department of Pediatrics, University of Pittsburgh School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania 15224
| | - Olga R Ilkayeva
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina 27701, and
| | - Dongning Wang
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina 27701, and
| | - Kevin McHugh
- From the Department of Pediatrics, University of Pittsburgh School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania 15224
| | - Ye Zou
- Department of Mechanical Engineering, University of Hawaii at Manoa, Honolulu, Hawaii 96822
| | - Jieru Wang
- From the Department of Pediatrics, University of Pittsburgh School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania 15224
| | - John F Alcorn
- From the Department of Pediatrics, University of Pittsburgh School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania 15224
| | - Yi Y Zuo
- Department of Mechanical Engineering, University of Hawaii at Manoa, Honolulu, Hawaii 96822
| | - Matthew D Hirschey
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina 27701, and
| | - Eric S Goetzman
- From the Department of Pediatrics, University of Pittsburgh School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania 15224,
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Derks TGJ, Touw CML, Ribas GS, Biancini GB, Vanzin CS, Negretto G, Mescka CP, Reijngoud DJ, Smit GPA, Wajner M, Vargas CR. Experimental evidence for protein oxidative damage and altered antioxidant defense in patients with medium-chain acyl-CoA dehydrogenase deficiency. J Inherit Metab Dis 2014; 37:783-9. [PMID: 24623196 DOI: 10.1007/s10545-014-9700-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 02/16/2014] [Accepted: 02/21/2014] [Indexed: 01/24/2023]
Abstract
The objective of this study was to test whether macromolecule oxidative damage and altered enzymatic antioxidative defenses occur in patients with medium-chain acyl coenzyme A dehydrogenase (MCAD) deficiency. We performed a cross-sectional observational study of in vivo parameters of lipid and protein oxidative damage and antioxidant defenses in asymptomatic, nonstressed, MCAD-deficient patients and healthy controls. Patients were subdivided into three groups based on therapy: patients without prescribed supplementation, patients with carnitine supplementation, and patients with carnitine plus riboflavin supplementation. Compared with healthy controls, nonsupplemented MCAD-deficient patients and patients receiving carnitine supplementation displayed decreased plasma sulfhydryl content (indicating protein oxidative damage). Increased erythrocyte superoxide dismutase (SOD) activity in patients receiving carnitine supplementation probably reflects a compensatory mechanism for scavenging reactive species formation. The combination of carnitine plus riboflavin was not associated with oxidative damage. These are the first indications that MCAD-deficient patients experience protein oxidative damage and that combined supplementation of carnitine and riboflavin may prevent these biochemical alterations. Results suggest involvement of free radicals in the pathophysiology of MCAD deficiency. The underlying mechanisms behind the increased SOD activity upon carnitine supplementation need to be determined. Further studies are necessary to determine the clinical relevance of oxidative stress, including the possibility of antioxidant therapy.
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Affiliation(s)
- Terry G J Derks
- Section of Metabolic Diseases, University Medical Center Groningen, University of Groningen, 9700, RB, Groningen, The Netherlands,
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Goldstein A, Wolfe LA. The elusive magic pill: finding effective therapies for mitochondrial disorders. Neurotherapeutics 2013; 10:320-8. [PMID: 23355364 PMCID: PMC3625379 DOI: 10.1007/s13311-012-0175-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The incidence of mitochondrial diseases has been estimated at 11.5/100,000 (1:8500) worldwide. In the USA up to 4000 newborns annually are expected to develop a mitochondrial disease. More than 50 million adults in the USA also suffer from diseases in which primary or secondary mitochondrial dysfunction is involved. Mitochondrial dysfunction has been identified in cancer, infertility, diabetes, heart diseases, blindness, deafness, kidney disease, liver disease, stroke, migraine, dwarfism, and resulting from numerous medication toxicities. Mitochondrial dysfunction is also involved in normal aging and age-related neurodegenerative diseases, such as Parkinson and Alzheimer diseases. Yet most treatments available are based on empiric data and clinician experience because of the lack of randomized controlled clinical trials to provide evidence-based treatments for these disorders. Here we explore the current state of research for the treatment of mitochondrial disorders.
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Affiliation(s)
- Amy Goldstein
- />Division of Child Neurology, Childrens Hospital of Pittsburgh of UPMC, Pittsburgh, PA USA
| | - Lynne A. Wolfe
- />Undiagnosed Diseases Program, National Institutes of Health, 10 Center DR, MSC 1205, RM# 3-2551, Bethesda, MD 20892 USA
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