1
|
West S, Monteyne AJ, van der Heijden I, Stephens FB, Wall BT. Nutritional Considerations for the Vegan Athlete. Adv Nutr 2023; 14:774-795. [PMID: 37127187 PMCID: PMC10334161 DOI: 10.1016/j.advnut.2023.04.012] [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] [Received: 02/22/2023] [Revised: 04/19/2023] [Accepted: 04/27/2023] [Indexed: 05/03/2023] Open
Abstract
Accepting a continued rise in the prevalence of vegan-type diets in the general population is also likely to occur in athletic populations, it is of importance to assess the potential impact on athletic performance, adaptation, and recovery. Nutritional consideration for the athlete requires optimization of energy, macronutrient, and micronutrient intakes, and potentially the judicious selection of dietary supplements, all specified to meet the individual athlete's training and performance goals. The purpose of this review is to assess whether adopting a vegan diet is likely to impinge on such optimal nutrition and, where so, consider evidence based yet practical and pragmatic nutritional recommendations. Current evidence does not support that a vegan-type diet will enhance performance, adaptation, or recovery in athletes, but equally suggests that an athlete can follow a (more) vegan diet without detriment. A clear caveat, however, is that vegan diets consumed spontaneously may induce suboptimal intakes of key nutrients, most notably quantity and/or quality of dietary protein and specific micronutrients (eg, iron, calcium, vitamin B12, and vitamin D). As such, optimal vegan sports nutrition requires (more) careful consideration, evaluation, and planning. Individual/seasonal goals, training modalities, athlete type, and sensory/cultural/ethical preferences, among other factors, should all be considered when planning and adopting a vegan diet.
Collapse
Affiliation(s)
- Sam West
- Public Health and Sport Sciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
| | - Alistair J Monteyne
- Public Health and Sport Sciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
| | - Ino van der Heijden
- Public Health and Sport Sciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
| | - Francis B Stephens
- Public Health and Sport Sciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
| | - Benjamin T Wall
- Public Health and Sport Sciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom.
| |
Collapse
|
2
|
Liammongkolkul S, Boonyawat B, Vijarnsorn C, Tim-Aroon T, Wasant P, Vatanavicharn N. Phenotypic and molecular features of Thai patients with primary carnitine deficiency. Pediatr Int 2023; 65:e15404. [PMID: 36321377 DOI: 10.1111/ped.15404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 09/13/2022] [Accepted: 09/22/2022] [Indexed: 11/07/2022]
Abstract
BACKGROUND Primary carnitine deficiency (PCD) is screened by expanded newborn screening (NBS) using tandem mass spectrometry (MS/MS) that can detect both affected neonates and mothers. This study aimed to delineate the clinical, biochemical, and molecular findings of Thai PCD patients. METHODS Expanded NBS using MS/MS was implemented in Bangkok and 146,757 neonates were screened between 2014 and 2018. PCD was screened by low free carnitine (C0) levels in dried blood spots. Plasma C0 levels and C0 clearance values were measured in neonates and their mothers with positive screening results. Clinically diagnosed cases were described. The coding regions and intron-exon boundaries of the SLC22A5 gene were sequenced in all cases with low plasma C0 levels. RESULTS There were 14 cases with confirmed PCD: two clinically diagnosed cases, and 12 cases identified through NBS including five newborns, six mothers, and one older sibling. Thus, the incidence of PCD in neonates was 1:29,351. All affected neonates and mothers were asymptomatic except one mother with dilated cardiomyopathy. SLC22A5 gene sequencing identified biallelic causative variants in all cases, comprising 10 different variants of which four were novel. c.51C > G (p.Phe17Leu) and c.760C > T (p.Arg254Ter) were the most prevalent variants in this study. Cases with significant clinical features tended to have higher C0 clearance values. CONCLUSIONS Primary carnitine deficiency is a common inherited metabolic disorder (IMD) in Thailand. Our findings broaden the spectrum of SLC22A5 variants. The future national NBS program will shed more light on PCD and other IMDs in Thailand.
Collapse
Affiliation(s)
- Somporn Liammongkolkul
- Division of Medical Genetics, Department of Pediatrics, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Boonchai Boonyawat
- Division of Medical Genetics, Department of Pediatrics, Phramongkutklao Hospital and College of Medicine, Bangkok, Thailand
| | - Chodchanok Vijarnsorn
- Division of Cardiology, Department of Pediatrics, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Thipwimol Tim-Aroon
- Division of Medical Genetics, Department of Pediatrics, Faculty of Medicine Ramathbodi Hospital, Mahidol University, Bangkok, Thailand
| | - Pornswan Wasant
- Division of Medical Genetics, Department of Pediatrics, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Nithiwat Vatanavicharn
- Division of Medical Genetics, Department of Pediatrics, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| |
Collapse
|
3
|
Jager EA, Schaafsma M, van der Klauw MM, Heiner‐Fokkema MR, Derks TGJ. Plasma carnitine concentrations in Medium-chain acyl-CoA dehydrogenase deficiency: lessons from an observational cohort study. J Inherit Metab Dis 2022; 45:1118-1129. [PMID: 35778950 PMCID: PMC9796739 DOI: 10.1002/jimd.12537] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 06/27/2022] [Accepted: 06/29/2022] [Indexed: 01/07/2023]
Abstract
Our aim was to study the effect of secondary carnitine deficiency (SCD) and carnitine supplementation on important outcome measures for persons with medium-chain Acyl-CoA dehydrogenase deficiency (MCADD). We performed a large retrospective observational study using all recorded visits of persons with MCADD in the University Medical Center Groningen, the Netherlands, between October 1994 and October 2019. Frequency and duration of acute unscheduled preventive hospital visits, exercise tolerance, fatigue, and muscle pain were considered important clinical outcomes and were studied in relation to (acyl)carnitine profile and carnitine supplementation status. The study encompassed 1228 visits of 93 persons with MCADD. >60% had SCD during follow-up. This included only persons with severe MCADD. Carnitine supplementation and SCD were unrelated to the frequency and duration of the acute unscheduled preventive hospital visits (P > 0.05). The relative risk for fatigue, muscle ache, or exercise intolerance was equal between persons with and without SCD (RR 1.6, 95% CI 0.48-5.10, P = 0.4662). No episodes of metabolic crisis were recorded in non-carnitine-supplemented persons with MCADD and SCD. In some persons with MCADD, SCD resolved without carnitine supplementation. There is absence of real-world evidence in favor of routine carnitine analysis and carnitine supplementation in the follow-up of persons with MCADD.
Collapse
Affiliation(s)
- Emmalie A. Jager
- Section of Metabolic DiseasesBeatrix Children's Hospital, University Medical Center Groningen, University of GroningenGroningenThe Netherlands
| | - Merit Schaafsma
- Section of Metabolic DiseasesBeatrix Children's Hospital, University Medical Center Groningen, University of GroningenGroningenThe Netherlands
| | - Melanie. M. van der Klauw
- Department of EndocrinologyUniversity of Groningen, University Medical Center GroningenGroningenThe Netherlands
| | - M. Rebecca Heiner‐Fokkema
- Laboratory of PediatricsUniversity of Groningen, University Medical Center GroningenGroningenThe Netherlands
| | - Terry G. J. Derks
- Section of Metabolic DiseasesBeatrix Children's Hospital, University Medical Center Groningen, University of GroningenGroningenThe Netherlands
| |
Collapse
|
4
|
PGC-1α and MEF2 Regulate the Transcription of the Carnitine Transporter OCTN2 Gene in C2C12 Cells and in Mouse Skeletal Muscle. Int J Mol Sci 2022; 23:ijms232012304. [PMID: 36293168 PMCID: PMC9604316 DOI: 10.3390/ijms232012304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 10/04/2022] [Accepted: 10/05/2022] [Indexed: 11/05/2022] Open
Abstract
OCTN2 (SLC22A5) is a carnitine transporter whose main function is the active transport of carnitine into cells. In skeletal muscle and other organs, the regulation of the SLC22A5 gene transcription has been shown to depend on the nuclear transcription factor PPAR-α. Due to the observation that the muscle OCTN2 mRNA level is maintained in PPAR-α knock-out mice and that PGC-1α overexpression in C2C12 myoblasts increases OCTN2 mRNA expression, we suspected additional regulatory pathways for SLC22A5 gene transcription. Indeed, we detected several binding sites of the myocyte-enhancing factor MEF2 in the upstream region of the SLC22A5 gene, and MEF2C/MEF2D stimulated the activity of the OCTN2 promoter in gene reporter assays. This stimulation was increased by PGC-1α and was blunted for a SLC22A5 promoter fragment with a mutated MEF2 binding site. Further, we demonstrated the specific binding of MEF2 to the SLC22A5 gene promoter, and a supershift of the MEF2/DNA complex in electrophoretic mobility shift assays. In immunoprecipitation experiments, we could demonstrate the interaction between PGC-1α and MEF2. In addition, SB203580, a specific inhibitor of p38 MAPK, blocked and interferon-γ stimulated the transcriptional activity of the SLC22A5 gene promoter. Finally, mice with muscle-specific overexpression of OCTN2 showed an increase in OCTN2 mRNA and protein expression in skeletal muscle. In conclusion, we detected and characterized a second stimulatory pathway of SLC22A5 gene transcription in skeletal muscle, which involves the nuclear transcription factor MEF2 and co-stimulation by PGC-1α and which is controlled by the p38 MAPK signaling cascade.
Collapse
|
5
|
Ringseis R, Grundmann SM, Schuchardt S, Most E, Eder K. Limited Impact of Pivalate-Induced Secondary Carnitine Deficiency on Hepatic Transcriptome and Hepatic and Plasma Metabolome in Nursery Pigs. Metabolites 2021; 11:metabo11090573. [PMID: 34564388 PMCID: PMC8468870 DOI: 10.3390/metabo11090573] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 08/23/2021] [Accepted: 08/24/2021] [Indexed: 11/16/2022] Open
Abstract
Administration of pivalate has been demonstrated to be suitable for the induction of secondary carnitine deficiency (CD) in pigs, as model objects for humans. In order to comprehensively characterize the metabolic effects of secondary CD in the liver of pigs, the present study aimed to carry out comparative analysis of the hepatic transcriptome and hepatic and plasma metabolome of a total of 12 male 5-week-old pigs administered either pivalate (group PIV, n = 6) or vehicle (group CON, n = 6) for 28 days. Pigs of group PIV had approximately 40-60% lower concentrations of free carnitine and acetylcarnitine in plasma, liver and different skeletal muscles than pigs of group CON (p < 0.05). Transcript profiling of the liver revealed 140 differentially expressed genes (DEGs) between group PIV and group CON (fold change > 1.2 or <-1.2, p-value < 0.05). Biological process terms dealing with the innate immune response were found to be enriched with the DEGs (p < 0.05). Using a targeted metabolomics approach for the simultaneous quantification of 630 metabolites, 9 liver metabolites and 18 plasma metabolites were identified to be different between group PIV and group CON (p < 0.05). Considering the limited alterations of the hepatic transcriptome and of the liver and plasma metabolome, it can be concluded that pivalate-induced secondary CD is not associated with significant hepatic metabolism changes in pigs.
Collapse
Affiliation(s)
- Robert Ringseis
- Institute of Animal Nutrition and Nutrition Physiology, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany; (S.M.G.); (E.M.); (K.E.)
- Correspondence:
| | - Sarah M. Grundmann
- Institute of Animal Nutrition and Nutrition Physiology, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany; (S.M.G.); (E.M.); (K.E.)
| | - Sven Schuchardt
- Fraunhofer Institute for Toxicology and Experimental Medicine (ITEM), Nikolai-Fuchs-Str.1, 30625 Hannover, Germany;
| | - Erika Most
- Institute of Animal Nutrition and Nutrition Physiology, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany; (S.M.G.); (E.M.); (K.E.)
| | - Klaus Eder
- Institute of Animal Nutrition and Nutrition Physiology, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany; (S.M.G.); (E.M.); (K.E.)
| |
Collapse
|
6
|
Jakoby M, Jaju A, Marsh A, Wilber A. Maternal Primary Carnitine Deficiency and a Novel Solute Carrier Family 22 Member 5 (SLC22A5) Mutation. J Investig Med High Impact Case Rep 2021; 9:23247096211019543. [PMID: 34032155 PMCID: PMC8155745 DOI: 10.1177/23247096211019543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Primary carnitine deficiency (PCD) is a rare autosomal recessive disorder caused
by loss of function mutations in the solute carrier family 22 member 5
(SLC22A5) gene that encodes a high-affinity
sodium-ion–dependent organic cation transporter protein (OCTN2). Reduced
carnitine transport results in diminished fatty acid oxidation in heart and
skeletal muscle and carnitine wasting in urine. We present a case of PCD
diagnosed in an adult female after a positive newborn screen (NBS) for PCD that
was not confirmed on follow-up testing. The mother was referred for evaluation
of persistent fatigue and possible hypothyroidism even though all measurements
of thyroid-stimulating hormone were well within the range of 0.4 to 2.5 mIU/L
expected for reproductive-age women. She was found to have unequivocally low
levels of both total carnitine and carnitine esters, and genetic testing
revealed compound heterozygosity for 2 SLC22A5 mutations. One mutation
(c.34G>A [p.Gly12Ser]) is a known missense mutation with partial OCTN2
activity, but the other mutation (c.41G>A [p.Trp14Ter]) is previously
unreported and results in a premature stop codon and truncated OCTN2. This case
illustrates that some maternal inborn errors of metabolism can be identified by
NBS and that maternal carnitine levels should be checked after a positive NBS
test for PCD.
Collapse
Affiliation(s)
| | - Amruta Jaju
- Southern Illinois University, Springfield, IL, USA
| | | | | |
Collapse
|
7
|
Abstract
The organic cation transporters (OCTs) OCT1, OCT2, OCT3, novel OCT (OCTN)1, OCTN2, multidrug and toxin exclusion (MATE)1, and MATE kidney-specific 2 are polyspecific transporters exhibiting broadly overlapping substrate selectivities. They transport organic cations, zwitterions, and some uncharged compounds and operate as facilitated diffusion systems and/or antiporters. OCTs are critically involved in intestinal absorption, hepatic uptake, and renal excretion of hydrophilic drugs. They modulate the distribution of endogenous compounds such as thiamine, L-carnitine, and neurotransmitters. Sites of expression and functions of OCTs have important impact on energy metabolism, pharmacokinetics, and toxicity of drugs, and on drug-drug interactions. In this work, an overview about the human OCTs is presented. Functional properties of human OCTs, including identified substrates and inhibitors of the individual transporters, are described. Sites of expression are compiled, and data on regulation of OCTs are presented. In addition, genetic variations of OCTs are listed, and data on their impact on transport, drug treatment, and diseases are reported. Moreover, recent data are summarized that indicate complex drug-drug interaction at OCTs, such as allosteric high-affinity inhibition of transport and substrate dependence of inhibitor efficacies. A hypothesis about the molecular mechanism of polyspecific substrate recognition by OCTs is presented that is based on functional studies and mutagenesis experiments in OCT1 and OCT2. This hypothesis provides a framework to imagine how observed complex drug-drug interactions at OCTs arise. Finally, preclinical in vitro tests that are performed by pharmaceutical companies to identify interaction of novel drugs with OCTs are discussed. Optimized experimental procedures are proposed that allow a gapless detection of inhibitory and transported drugs.
Collapse
Affiliation(s)
- Hermann Koepsell
- Institute of Anatomy and Cell Biology and Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, University of Würzburg, Würzburg, Germany
| |
Collapse
|
8
|
Abstract
This chapter focuses on the methods to measure unique metabolites, specific enzymes, and metabolic flux in fatty acid β-oxidation, and on biochemical assays of tricarboxylic acid (TCA) cycle enzymes and the pyruvate dehydrogenase complex. These assays play an important role in the diagnosis of genetic diseases, newborn screening, and in cancer and metabolism research. The rationale, protocol, pros and cons, and alternative methods are discussed. Nevertheless, each laboratory should adapt the preferred method optimizing sample preparation and assay conditions for linearity and a low signal-to-noise ratio. The reader is also referred to the additional literature citing methods and clinical descriptions of the various diseases.
Collapse
|
9
|
Wilson C, Knoll D, de Hora M, Kyle C, Glamuzina E, Webster D. The decision to discontinue screening for carnitine uptake disorder in New Zealand. J Inherit Metab Dis 2019; 42:86-92. [PMID: 30740730 DOI: 10.1002/jimd.12030] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
When screening for carnitine uptake disorder (CUD), the New Zealand (NZ) newborn screening (NBS) service identified infants as screen-positive if they had initial and repeat free carnitine (C0) levels of less than 5.0 μmol/L. Since 2006, the NBS service has identified two infants with biochemical and genetic features consistent with neonatal CUD and nine mothers with features consistent with maternal CUD. A review of the literature suggests that these nine women reflect less than half the true prevalence and that CUD is relatively common. However, the NZ results (two infants) suggest a very low sensitivity and positive predictive value of NBS. While patients presenting with significant disease due to CUD are well described, the majority of adults with CUD are asymptomatic. Nonetheless, treatment with high-dose oral L-carnitine is recommended. Compliance with oral L-carnitine is likely to be poor long term. This may represent a specific risk as treatment could repress the usual compensatory mechanisms seen in CUD, such that a sudden discontinuation of treatment may be dangerous. L-carnitine is metabolized to trimethylamine-N-oxide (TMAO) and treated patients have extremely high plasma TMAO levels. TMAO is an independent risk factor for atherosclerosis and, thus, caution should be exercised regarding long-term treatment with high-dose carnitine of asymptomatic patients who may have a biochemical profile without disease. Due to these concerns, the NZ Newborn Metabolic Screening Programme (NMSP) initiated a review via a series of advisory and governance committees and decided to discontinue screening for CUD.
Collapse
Affiliation(s)
- Callum Wilson
- National Metabolic Service, Starship Children's Hospital, P.O. Box 92024, Auckland 1142, New Zealand
| | - Detlef Knoll
- Newborn Metabolic Screening Unit, Auckland City Hospital, Auckland, New Zealand
| | - Mark de Hora
- Newborn Metabolic Screening Programme, LabPlus, Auckland City Hospital, Auckland, New Zealand
| | - Campbell Kyle
- LabPlus, Auckland City Hospital, Auckland, New Zealand
| | - Emma Glamuzina
- National Metabolic Service, Starship Children's Hospital, P.O. Box 92024, Auckland 1142, New Zealand
| | - Dianne Webster
- Newborn Metabolic Screening Programme, LabPlus, Auckland City Hospital, Auckland, New Zealand
| |
Collapse
|
10
|
Madsen KL, Preisler N, Rasmussen J, Hedermann G, Olesen JH, Lund AM, Vissing J. L-Carnitine Improves Skeletal Muscle Fat Oxidation in Primary Carnitine Deficiency. J Clin Endocrinol Metab 2018; 103:4580-4588. [PMID: 30219858 DOI: 10.1210/jc.2018-00953] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 09/10/2018] [Indexed: 12/30/2022]
Abstract
CONTEXT Primary carnitine deficiency (PCD) is an inborn error of fatty acid metabolism. Patients with PCD are risk for sudden heart failure upon fasting or illness if they are not treated with daily l-carnitine. OBJECTIVE To investigate energy metabolism during exercise in patients with PCD with and without l-carnitine treatment. DESIGN Interventional study. SETTING Hospital exercise laboratories and department of cardiology. PARTICIPANTS Eight adults with PCD who were homozygous for the c.95A>G (p.N32S) mutation and 10 healthy age- and sex-matched controls. INTERVENTION Four-day pause in l-carnitine treatment. MAIN OUTCOME MEASURES Total fatty acid and palmitate oxidation rates during 1-hour submaximal cycle ergometer exercise assessed with stable isotope method (U13C-palmitate and 2H2-d-glucose) and indirect calorimetry with and without l-carnitine. RESULTS Total fatty acid oxidation rate was higher in patients with l-carnitine treatment during exercise than without treatment [12.3 (SD, 3.7) vs 8.5 (SD, 4.6) µmol × kg-1 × min-1; P = 0.008]. However, the fatty acid oxidation rate was still lower in patients treated with l-carnitine than in the healthy controls [29.5 (SD, 10.1) µmol × kg-1 × min-1; P < 0.001] and in the l-carnitine group without treatment it was less than one third of that in the healthy controls (P < 0.001). In line with this, the palmitate oxidation rates during exercise were lower in the no-treatment period [144 (SD, 66) µmol × kg-1 × min-1] than during treatment [204 (SD, 84) µmol × kg-1 × min-1; P = 0.004) . CONCLUSIONS The results indicate that patients with PCD have limited fat oxidation during exercise. l-Carnitine treatment in asymptomatic patients with PCD may not only prevent cardiac complications but also boost skeletal muscle fat metabolism during exercise.
Collapse
Affiliation(s)
- Karen Lindhardt Madsen
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, Copenhagen, Denmark
| | - Nicolai Preisler
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, Copenhagen, Denmark
| | - Jan Rasmussen
- Department of Internal Medicine, The National Hospital of the Faroe Islands, Tórshavn, Faroe Islands
| | - Gitte Hedermann
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, Copenhagen, Denmark
| | - Jess Have Olesen
- Centre for Inherited Metabolic Diseases, Department of Clinical Genetics, Rigshospitalet, Copenhagen, Denmark
| | - Allan Meldgaard Lund
- Centre for Inherited Metabolic Diseases, Department of Clinical Genetics, Rigshospitalet, Copenhagen, Denmark
| | - John Vissing
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, Copenhagen, Denmark
| |
Collapse
|
11
|
Cortés R, Kleinsteuber K, Paz Vargas C, de Los Ángeles Avaria M. Miopatías metabólicas. REVISTA MÉDICA CLÍNICA LAS CONDES 2018. [DOI: 10.1016/j.rmclc.2018.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
|
12
|
Li JM, Li LY, Qin X, Degrace P, Demizieux L, Limbu SM, Wang X, Zhang ML, Li DL, Du ZY. Inhibited Carnitine Synthesis Causes Systemic Alteration of Nutrient Metabolism in Zebrafish. Front Physiol 2018; 9:509. [PMID: 29867554 PMCID: PMC5954090 DOI: 10.3389/fphys.2018.00509] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 04/20/2018] [Indexed: 12/30/2022] Open
Abstract
Impaired mitochondrial fatty acid β-oxidation has been correlated with many metabolic syndromes, and the metabolic characteristics of the mammalian models of mitochondrial dysfunction have also been intensively studied. However, the effects of the impaired mitochondrial fatty acid β-oxidation on systemic metabolism in teleost have never been investigated. In the present study, we established a low-carnitine zebrafish model by feeding fish with mildronate as a specific carnitine synthesis inhibitor [0.05% body weight (BW)/d] for 7 weeks, and the systemically changed nutrient metabolism, including carnitine and triglyceride (TG) concentrations, fatty acid (FA) β-oxidation capability, and other molecular and biochemical assays of lipid, glucose, and protein metabolism, were measured. The results indicated that mildronate markedly decreased hepatic carnitine concentrations while it had no effect in muscle. Liver TG concentrations increased by more than 50% in mildronate-treated fish. Mildronate decreased the efficiency of liver mitochondrial β-oxidation, increased the hepatic mRNA expression of genes related to FA β-oxidation and lipolysis, and decreased the expression of lipogenesis genes. Mildronate decreased whole body glycogen content, increased glucose metabolism rate, and upregulated the expression of glucose uptake and glycolysis genes. Mildronate also increased whole body protein content and hepatic mRNA expression of mechanistic target of rapamycin (mtor), and decreased the expression of a protein catabolism-related gene. Liver, rather than muscle, was the primary organ targeted by mildronate. In short, mildronate-induced hepatic inhibited carnitine synthesis in zebrafish caused decreased mitochondrial FA β-oxidation efficiency, greater lipid accumulation, and altered glucose and protein metabolism. This reveals the key roles of mitochondrial fatty acid β-oxidation in nutrient metabolism in fish, and this low-carnitine zebrafish model could also be used as a novel fish model for future metabolism studies.
Collapse
Affiliation(s)
- Jia-Min Li
- Laboratory of Aquaculture Nutrition and Environmental Health, School of Life Sciences, East China Normal University, Shanghai, China
| | - Ling-Yu Li
- Laboratory of Aquaculture Nutrition and Environmental Health, School of Life Sciences, East China Normal University, Shanghai, China
| | - Xuan Qin
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Pascal Degrace
- Team Pathophysiology of Dyslipidemia, Faculty of Sciences Gabriel, INSERM UMR1231 "Lipides, Nutrition, Cancer," Université Bourgogne Franche-Comté, Dijon, France
| | - Laurent Demizieux
- Team Pathophysiology of Dyslipidemia, Faculty of Sciences Gabriel, INSERM UMR1231 "Lipides, Nutrition, Cancer," Université Bourgogne Franche-Comté, Dijon, France
| | - Samwel M Limbu
- Laboratory of Aquaculture Nutrition and Environmental Health, School of Life Sciences, East China Normal University, Shanghai, China.,Department of Aquatic Sciences and Fisheries Technology, University of Dar es Salaam, Dar es Salaam, Tanzania
| | - Xin Wang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Mei-Ling Zhang
- Laboratory of Aquaculture Nutrition and Environmental Health, School of Life Sciences, East China Normal University, Shanghai, China
| | - Dong-Liang Li
- Laboratory of Aquaculture Nutrition and Environmental Health, School of Life Sciences, East China Normal University, Shanghai, China
| | - Zhen-Yu Du
- Laboratory of Aquaculture Nutrition and Environmental Health, School of Life Sciences, East China Normal University, Shanghai, China
| |
Collapse
|
13
|
Carnitine/organic cation transporter 2 (OCTN2) contributes to rat epididymal epithelial cell growth and proliferation. Biomed Pharmacother 2017; 93:444-450. [DOI: 10.1016/j.biopha.2017.06.057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 06/12/2017] [Accepted: 06/19/2017] [Indexed: 01/14/2023] Open
|
14
|
Krähenbühl S. Importance of the skeletal muscle carnitine stores in fuel selection. J Physiol 2017; 595:5727-5728. [DOI: 10.1113/jp274755] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Stephan Krähenbühl
- Clinical Pharmacology & Toxicology; University Hospital Basel; Basel Switzerland
| |
Collapse
|
15
|
Abstract
Among the various metabolic abnormalities documented in dialysis patients are abnormalities related to the metabolism of fatty acids. Aberrant fatty-acid metabolism has been associated with the promotion of free-radical production, insulin resistance, and cellular apoptosis. These processes have been identified as important contributors to the morbidity experienced by dialysis patients. There is evidence that levocarnitine supplementation can modify the deleterious effects of defective fatty-acid metabolism. Patients receiving hemodialysis and, to a lesser degree, peritoneal dialysis have been shown to be carnitine deficient, as manifested by reduced levels of plasma free carnitine and an increase in the acyl:free carnitine ratio. Cardiac and skeletal muscles are particularly dependent on fatty-acid metabolism for the generation of energy. A number of clinical abnormalities have been correlated with a low plasma carnitine status in dialysis patients. Clinical trials have examined the efficacy of levocarnitine therapy in a number of conditions common in dialysis patients, including skeletal-muscle weakness and fatigue, cardiomyopathy, dialysis-related hypotension, hyperlipidemia, and anemia poorly responsive to recombinant human erythropoietin therapy (rHuEPO). This review examines the evidence for carnitine deficiency in patients requiring dialysis, and documents the results of relevant clinical trials of levocarnitine therapy in this population. Consensus recommendations by expert panels are summarized and contrasted with present guidelines for access to levocarnitine therapy by dialysis patients.
Collapse
Affiliation(s)
- Brian Schreiber
- Dialysis Care, Department of Medicine, Division of Nephrology, Medical College of Wisconsin, Milwaukee, WI, USA.
| |
Collapse
|
16
|
Bouitbir J, Haegler P, Singh F, Joerin L, Felser A, Duthaler U, Krähenbühl S. Impaired Exercise Performance and Skeletal Muscle Mitochondrial Function in Rats with Secondary Carnitine Deficiency. Front Physiol 2016; 7:345. [PMID: 27559315 PMCID: PMC4978712 DOI: 10.3389/fphys.2016.00345] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 07/28/2016] [Indexed: 01/17/2023] Open
Abstract
Purpose: The effects of carnitine depletion upon exercise performance and skeletal muscle mitochondrial function remain largely unexplored. We therefore investigated the effect of N-trimethyl-hydrazine-3-propionate (THP), a carnitine analog inhibiting carnitine biosynthesis and renal carnitine reabsorption, on physical performance and skeletal muscle mitochondrial function in rats. Methods: Male Sprague Dawley rats were treated daily with water (control rats; n = 12) or with 20 mg/100 g body weight THP (n = 12) via oral gavage for 3 weeks. Following treatment, half of the animals of each group performed an exercise test until exhaustion. Results: Distance covered and exercise performance were lower in THP-treated compared to control rats. In the oxidative soleus muscle, carnitine depletion caused atrophy (–24%) and impaired function of complex II and IV of the mitochondrial electron transport chain. The free radical leak (ROS production relative to oxygen consumption) was increased and the cellular glutathione pool decreased. Moreover, mRNA expression of markers of mitochondrial biogenesis and mitochondrial DNA were decreased in THP-treated compared to control rats. In comparison, in the glycolytic gastrocnemius muscle, carnitine depletion was associated with impaired function of complex IV and increased free radical leak, whilst muscle weight and cellular glutathione pool were maintained. Markers of mitochondrial proliferation and mitochondrial DNA were unaffected. Conclusions: Carnitine deficiency is associated with impaired exercise capacity in rats treated with THP. THP-induced carnitine deficiency is associated with impaired function of the electron transport chain in oxidative and glycolytic muscle as well as with atrophy and decreased mitochondrial DNA in oxidative muscle.
Collapse
Affiliation(s)
- Jamal Bouitbir
- Department of Clinical Pharmacology and Toxicology, University Hospital BaselBasel, Switzerland; Department of Biomedicine, University of BaselBasel, Switzerland; Swiss Centre of Applied Human ToxicologyBasel, Switzerland
| | - Patrizia Haegler
- Department of Clinical Pharmacology and Toxicology, University Hospital BaselBasel, Switzerland; Department of Biomedicine, University of BaselBasel, Switzerland
| | - François Singh
- Department of Clinical Pharmacology and Toxicology, University Hospital BaselBasel, Switzerland; Department of Biomedicine, University of BaselBasel, Switzerland; Fédération de Médecine Translationelle, Faculté de Médecine, Institut de Physiologie, Université de StrasbourgStrasbourg, France
| | - Lorenz Joerin
- Department of Clinical Pharmacology and Toxicology, University Hospital BaselBasel, Switzerland; Department of Biomedicine, University of BaselBasel, Switzerland
| | - Andrea Felser
- Department of Clinical Pharmacology and Toxicology, University Hospital BaselBasel, Switzerland; Department of Biomedicine, University of BaselBasel, Switzerland
| | - Urs Duthaler
- Department of Clinical Pharmacology and Toxicology, University Hospital BaselBasel, Switzerland; Department of Biomedicine, University of BaselBasel, Switzerland
| | - Stephan Krähenbühl
- Department of Clinical Pharmacology and Toxicology, University Hospital BaselBasel, Switzerland; Department of Biomedicine, University of BaselBasel, Switzerland; Swiss Centre of Applied Human ToxicologyBasel, Switzerland
| |
Collapse
|
17
|
Frigeni M, Iacobazzi F, Yin X, Longo N. Wide tolerance to amino acids substitutions in the OCTN1 ergothioneine transporter. Biochim Biophys Acta Gen Subj 2016; 1860:1334-42. [PMID: 26994919 DOI: 10.1016/j.bbagen.2016.03.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 02/24/2016] [Accepted: 03/15/2016] [Indexed: 12/30/2022]
Abstract
BACKGROUND Organic cation transporters transfer solutes with a positive charge across the plasma membrane. The novel organic cation transporter 1 (OCTN1) and 2 (OCTN2) transport ergothioneine and carnitine, respectively. Mutations in the SLC22A5 gene encoding OCTN2 cause primary carnitine deficiency, a recessive disorders resulting in low carnitine levels and defective fatty acid oxidation. Variations in the SLC22A4 gene encoding OCTN1 are associated with rheumatoid arthritis and Crohn disease. METHODS Here we evaluate the functional properties of the OCTN1 transporter using chimeric transporters constructed by fusing different portion of the OCTN1 and OCTN2 cDNAs. Their relative abundance and subcellular distribution was evaluated through western blot analysis and confocal microscopy. RESULTS Substitutions of the C-terminal portion of OCTN1 with the correspondent residues of OCTN2 generated chimeric OCTN transporters more active than wild-type OCTN1 in transporting ergothioneine. Additional single amino acid substitutions introduced in chimeric OCTN transporters further increased ergothioneine transport activity. Kinetic analysis indicated that increased transport activity was due to an increased V(max), with modest changes in K(m) toward ergothioneine. CONCLUSIONS Our results indicate that the OCTN1 transporter is tolerant to extensive amino acid substitutions. This is in sharp contrast to the OCTN2 carnitine transporter that has been selected for high functional activity through evolution, with almost all substitutions reducing carnitine transport activity. GENERAL SIGNIFICANCE The widespread tolerance of OCTN1 to amino acid substitutions suggests that the corresponding SLC22A4 gene may have derived from a recent duplication of the SLC22A5 gene and might not yet have a defined physiological role.
Collapse
Affiliation(s)
- Marta Frigeni
- Division of Medical Genetics, Departments of Pediatrics and Pathology, University of Utah, Salt Lake City, UT 84108, United States
| | - Francesco Iacobazzi
- Division of Medical Genetics, Departments of Pediatrics and Pathology, University of Utah, Salt Lake City, UT 84108, United States; Department of Basic Medical Sciences, University of Bari, Policlinico, I-70124 Bari, Italy
| | - Xue Yin
- Division of Medical Genetics, Departments of Pediatrics and Pathology, University of Utah, Salt Lake City, UT 84108, United States
| | - Nicola Longo
- Division of Medical Genetics, Departments of Pediatrics and Pathology, University of Utah, Salt Lake City, UT 84108, United States.
| |
Collapse
|
18
|
Shannon CE, Nixon AV, Greenhaff PL, Stephens FB. Protein ingestion acutely inhibits insulin-stimulated muscle carnitine uptake in healthy young men. Am J Clin Nutr 2016; 103:276-82. [PMID: 26675771 PMCID: PMC4756606 DOI: 10.3945/ajcn.115.119826] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 10/26/2015] [Indexed: 10/22/2022] Open
Abstract
BACKGROUND Increasing skeletal muscle carnitine content represents an appealing intervention in conditions of perturbed lipid metabolism such as obesity and type 2 diabetes but requires chronic L-carnitine feeding on a daily basis in a high-carbohydrate beverage. OBJECTIVE We investigated whether whey protein ingestion could reduce the carbohydrate load required to stimulate insulin-mediated muscle carnitine accretion. DESIGN Seven healthy men [mean ± SD age: 24 ± 5 y; body mass index (in kg/m(2)): 23 ± 3] ingested 80 g carbohydrate, 40 g carbohydrate + 40 g protein, or control (flavored water) beverages 60 min after the ingestion of 4.5 g L-carnitine tartrate (3 g L-carnitine; 0.1% (2)[H]3-L-carnitine). Serum insulin concentration, net forearm carnitine balance (NCB; arterialized-venous and venous plasma carnitine difference × brachial artery flow), and carnitine disappearance (Rd) and appearance (Ra) rates were determined at 20-min intervals for 180 min. RESULTS Serum insulin and plasma flow areas under the curve (AUCs) were similarly elevated by carbohydrate [4.5 ± 0.8 U/L · min (P < 0.01) and 0.5 ± 0.6 L (P < 0.05), respectively] and carbohydrate+protein [3.8 ± 0.6 U/L · min (P < 0.01) and 0.4 ± 0.6 L (P = 0.05), respectively] consumption, respectively, compared with the control visit (0.04 ± 0.1 U/L · min and -0.5 ± 0.2 L). Plasma carnitine AUC was greater after carbohydrate+protein consumption (3.5 ± 0.5 mmol/L · min) than after control and carbohydrate visits [2.1 ± 0.2 mmol/L · min (P < 0.05) and 1.9 ± 0.3 mmol/L · min (P < 0.01), respectively]. NCB AUC with carbohydrate (4.1 ± 3.1 μmol) was greater than during control and carbohydrate-protein visits (-8.6 ± 3.0 and -14.6 ± 6.4 μmol, respectively; P < 0.05), as was Rd AUC after carbohydrate (35.7 ± 25.2 μmol) compared with control and carbohydrate consumption [19.7 ± 15.5 μmol (P = 0.07) and 14.8 ± 9.6 μmol (P < 0.05), respectively]. CONCLUSIONS The insulin-mediated increase in forearm carnitine balance with carbohydrate consumption was acutely blunted by a carbohydrate+protein beverage, which suggests that carbohydrate+protein could inhibit chronic muscle carnitine accumulation.
Collapse
Affiliation(s)
- Chris E Shannon
- Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, United Kingdom
| | - Aline V Nixon
- Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, United Kingdom
| | - Paul L Greenhaff
- Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, United Kingdom
| | - Francis B Stephens
- Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, United Kingdom
| |
Collapse
|
19
|
El-Hattab AW, Scaglia F. Disorders of carnitine biosynthesis and transport. Mol Genet Metab 2015; 116:107-12. [PMID: 26385306 DOI: 10.1016/j.ymgme.2015.09.004] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 09/05/2015] [Accepted: 09/06/2015] [Indexed: 12/30/2022]
Abstract
Carnitine is a hydrophilic quaternary amine that plays a number of essential roles in metabolism with the main function being the transport of long-chain fatty acids from the cytosol to the mitochondrial matrix for β-oxidation. Carnitine can be endogenously synthesized. However, only a small fraction of carnitine is obtained endogenously while the majority is obtained from diet, mainly animal products. Carnitine is not metabolized and is excreted in urine. Carnitine homeostasis is regulated by efficient renal reabsorption that maintains carnitine levels within the normal range despite variabilities in dietary intake. Diseases occurring due to primary defects in carnitine metabolism and homeostasis are comprised in two groups: disorders of carnitine biosynthesis and carnitine transport defect. While the hallmark of carnitine transport defect is profound carnitine depletion, disorders of carnitine biosynthesis do not cause carnitine deficiency due to the fact that both carnitine obtained from diet and efficient renal carnitine reabsorption can maintain normal carnitine levels with the absence of endogenously synthesized carnitine. Carnitine transport defect phenotype encompasses a broad clinical spectrum including metabolic decompensation in infancy, cardiomyopathy in childhood, fatigability in adulthood, or absence of symptoms. The phenotypes associated with the carnitine transport defect result from the unavailability of enough carnitine to perform its functions particularly in fatty acid β-oxidation. Carnitine biosynthetic defects have been recently described and the phenotypic consequences of these defects are still emerging. Although these defects do not result in carnitine deficiency, they still could be associated with pathological phenotypes due to excess or deficiency of intermediate metabolites in the carnitine biosynthetic pathway and potential carnitine deficiency in early stages of life when brain and other organs develop. In addition to these two groups of primary carnitine defects, several metabolic diseases and medical conditions can result in excessive carnitine loss leading to a secondary carnitine deficiency.
Collapse
Affiliation(s)
- Ayman W El-Hattab
- Division of Clinical Genetics and Metabolic Disorders, Department of Pediatrics, Tawam Hospital, Al-Ain, United Arab Emirates
| | - Fernando Scaglia
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
| |
Collapse
|
20
|
Roberts PA, Bouitbir J, Bonifacio A, Singh F, Kaufmann P, Urwyler A, Krähenbühl S. Contractile function and energy metabolism of skeletal muscle in rats with secondary carnitine deficiency. Am J Physiol Endocrinol Metab 2015; 309:E265-74. [PMID: 26037247 DOI: 10.1152/ajpendo.00001.2015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 05/26/2015] [Indexed: 11/22/2022]
Abstract
The consequences of carnitine depletion upon metabolic and contractile characteristics of skeletal muscle remain largely unexplored. Therefore, we investigated the effect of N-trimethyl-hydrazine-3-propionate (THP) administration, a carnitine analog inhibiting carnitine biosynthesis and renal reabsorption of carnitine, on skeletal muscle function and energy metabolism. Male Sprague-Dawley rats were fed a standard rat chow in the absence (CON; n = 8) or presence of THP (n = 8) for 3 wk. Following treatment, rats were fasted for 24 h prior to excision of their soleus and EDL muscles for biochemical characterization at rest and following 5 min of contraction in vitro. THP treatment reduced the carnitine pool by ∼80% in both soleus and EDL muscles compared with CON. Carnitine depletion was associated with a 30% decrease soleus muscle weight, whereas contractile function (expressed per gram of muscle), free coenzyme A, and water content remained unaltered from CON. Muscle fiber distribution and fiber area remained unaffected, whereas markers of apoptosis were increased in soleus muscle of THP-treated rats. In EDL muscle, carnitine depletion was associated with reduced free coenzyme A availability (-25%, P < 0.05), impaired peak tension development (-44%, P < 0.05), and increased glycogen hydrolysis (52%, P < 0.05) during muscle contraction, whereas PDC activation, muscle weight, and water content remained unaltered from CON. In conclusion, myopathy associated with carnitine deficiency can have different causes. Although muscle atrophy, most likely due to increased apoptosis, is predominant in muscle composed predominantly of type I fibers (soleus), disturbance of energy metabolism appears to be the major cause in muscle composed of type II fibers (EDL).
Collapse
Affiliation(s)
- Paul A Roberts
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, and
| | - Jamal Bouitbir
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, and
| | - Annalisa Bonifacio
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, and
| | - François Singh
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, and
| | - Priska Kaufmann
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, and
| | - Albert Urwyler
- Department of Biomedicine, and Department of Anesthesia, University Hospital Basel, Basel, Switzerland
| | - Stephan Krähenbühl
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, and
| |
Collapse
|
21
|
Hitomi T, Matsuura N, Shigematsu Y, Okano Y, Shinozaki E, Kawai M, Kobayashi H, Harada KH, Koizumi A. Importance of molecular diagnosis in the accurate diagnosis of systemic carnitine deficiency. J Genet 2015; 94:147-50. [PMID: 25846890 DOI: 10.1007/s12041-015-0486-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Toshiaki Hitomi
- Department of Health and Environmental Sciences, Kyoto University Graduate School of Medicine, Yoshida Konoecho, Kyoto 606-8501, Japan.
| | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Ochiai H, Kanemaki N, Sato R, Onda K. Distribution, molecular structure and functional analysis of carnitine transporter (SLC22A5) in canine lens epithelial cells. Exp Anim 2014; 63:467-73. [PMID: 25048262 PMCID: PMC4244295 DOI: 10.1538/expanim.63.467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
While carnitine has been reported to have an anti-oxidative role on the ocular surface,
there has been no report on the existence of a carnitine transporter (SLC22A5) in the
lens. Therefore, we investigated the carnitine transport activity of canine lens
epithelial cells (LEC) and determined the molecular structure of canine
SLC22A5. The carnitine transport activity was 7.16 ± 0.48 pmol/mg
protein/30 min. Butyrobetaine, the analogue of carnitine, reduced 30% of the activity at
50 µM. A coding sequence of canine carnitine transporter was 1694 bp
long and was predicted to encode 557 amino acid polypeptides. The deduced amino acid
sequence of canine carnitine transporter showed >80% similarity to that of mouse and
human. Western blot analysis detected the band at 60 kDa in the membrane of lens
epithelial cells. The high content of carnitine in the lens is possibly transported from
aqueous humor by SLC22A5.
Collapse
Affiliation(s)
- Hideharu Ochiai
- Research Institute of Biosciences, Azabu University, 1-17-71 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5201, Japan
| | | | | | | |
Collapse
|
23
|
Rashidi-Nezhad A, Talebi S, Saebnouri H, Akrami SM, Reymond A. The effect of homozygous deletion of the BBOX1 and Fibin genes on carnitine level and acyl carnitine profile. BMC MEDICAL GENETICS 2014; 15:75. [PMID: 24986124 PMCID: PMC4184381 DOI: 10.1186/1471-2350-15-75] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2013] [Accepted: 06/26/2014] [Indexed: 11/10/2022]
Abstract
Background Carnitine is a key molecule in energy metabolism that helps transport activated fatty acids into the mitochondria. Its homeostasis is achieved through oral intake, renal reabsorption and de novo biosynthesis. Unlike dietary intake and renal reabsorption, the importance of de novo biosynthesis pathway in carnitine homeostasis remains unclear, due to lack of animal models and description of a single patient defective in this pathway. Case presentation We identified by array comparative genomic hybridization a 42 months-old girl homozygote for a 221 Kb interstitial deletions at 11p14.2, that overlaps the genes encoding Fibin and butyrobetaine-gamma 2-oxoglutarate dioxygenase 1 (BBOX1), an enzyme essential for the biosynthesis of carnitine de novo. She presented microcephaly, speech delay, growth retardation and minor facial anomalies. The levels of almost all evaluated metabolites were normal. Her serum level of free carnitine was at the lower limit of the reference range, while her acylcarnitine to free carnitine ratio was normal. Conclusions We present an individual with a completely defective carnitine de novo biosynthesis. This condition results in mildly decreased free carnitine level, but not in clinical manifestations characteristic of carnitine deficiency disorders, suggesting that dietary carnitine intake and renal reabsorption are sufficient to carnitine homeostasis. Our results also demonstrate that haploinsufficiency of BBOX1 and/or Fibin is not associated with Primrose syndrome as previously suggested.
Collapse
Affiliation(s)
| | | | | | - Seyed Mohammad Akrami
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.
| | | |
Collapse
|
24
|
Abstract
Recognition of fatty acid oxidation (FAO) disorders is important for the pediatric neurologist as they present with a spectrum of clinical disorders, including progressive lipid storage myopathy, recurrent myoglobinuria, neuropathy, progressive cardiomyopathy, recurrent hypoglycemic hypoketotic encephalopathy or Reye-like syndrome, seizures, and mental retardation. They constitute a critical group of diseases because they are potentially rapidly fatal and a source of major morbidity. There is frequently a family history of sudden infant death syndrome in siblings. Early recognition and prompt institution of therapy and appropriate preventive measures, and in certain cases specific therapy, may be life-saving and may significantly decrease long-term morbidity, particularly with respect to CNS sequelae. All currently known conditions are inherited as autosomal recessive traits. There are now at least 25 enzymes and specific transport proteins in the β-oxidation pathway and 18 have been associated with human disease. The most common defect is medium-chain acyl-CoA dehydrogenase (MCAD) deficiency, which had an incidence of 1 in 8930 live births in one series. The identification of serum acylcarnitines by electrospray ionization-tandem mass spectrometry of dried blood spots on filter paper in newborn screening programs has significantly enhanced the early recognition of these disorders.
Collapse
Affiliation(s)
- Ingrid Tein
- Neurometabolic Clinic and Research Laboratory, Division of Neurology and Genetics and Genome Biology Program, Research Institute, Hospital for Sick Children, University of Toronto, Toronto, Canada.
| |
Collapse
|
25
|
OCHIAI H, KANEMAKI N, SATO R, ONDA K. Distribution, Molecular Structure and Functional Analysis of Carnitine Transporter (SLC22A5) in Canine Lens Epithelial Cells. Exp Anim 2014. [DOI: 10.1538/expanim.14-0020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Affiliation(s)
- Hideharu OCHIAI
- Research Institute of Biosciences, Azabu University, 1-17-71 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5201, Japan
| | | | - Reiichiro SATO
- Laboratory of Internal Medicine 3, Azabu University, School of Veterinary Medicine, Japan
| | - Ken ONDA
- Laboratory of Internal Medicine 3, Azabu University, School of Veterinary Medicine, Japan
| |
Collapse
|
26
|
Reuter SE, Evans AM. Carnitine and acylcarnitines: pharmacokinetic, pharmacological and clinical aspects. Clin Pharmacokinet 2012; 51:553-72. [PMID: 22804748 DOI: 10.1007/bf03261931] [Citation(s) in RCA: 310] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
L-Carnitine (levocarnitine) is a naturally occurring compound found in all mammalian species. The most important biological function of L-carnitine is in the transport of fatty acids into the mitochondria for subsequent β-oxidation, a process which results in the esterification of L-carnitine to form acylcarnitine derivatives. As such, the endogenous carnitine pool is comprised of L-carnitine and various short-, medium- and long-chain acylcarnitines. The physiological importance of L-carnitine and its obligatory role in the mitochondrial metabolism of fatty acids has been clearly established; however, more recently, additional functions of the carnitine system have been described, including the removal of excess acyl groups from the body and the modulation of intracellular coenzyme A (CoA) homeostasis. In light of this, acylcarnitines cannot simply be considered by-products of the enzymatic carnitine transfer system, but provide indirect evidence of altered mitochondrial metabolism. Consequently, examination of the contribution of L-carnitine and acylcarnitines to the endogenous carnitine pool (i.e. carnitine pool composition) is critical in order to adequately characterize metabolic status. The concentrations of L-carnitine and its esters are maintained within relatively narrow limits for normal biological functioning in their pivotal roles in fatty acid oxidation and maintenance of free CoA availability. The homeostasis of carnitine is multifaceted with concentrations achieved and maintained by a combination of oral absorption, de novo biosynthesis, carrier-mediated distribution into tissues and extensive, but saturable, renal tubular reabsorption. Various disorders of carnitine insufficiency have been described but ultimately all result in impaired entry of fatty acids into the mitochondria and consequently disturbed lipid oxidation. Given the sensitivity of acylcarnitine concentrations and the relative carnitine pool composition in reflecting the intramitochondrial acyl-CoA to free CoA ratio (and, hence, any disturbances in mitochondrial metabolism), the relative contribution of L-carnitine and acylcarnitines within the total carnitine pool is therefore considered critical in the identification of mitochondria dysfunction. Although there is considerable research in the literature focused on disorders of carnitine insufficiency, relatively few have examined relative carnitine pool composition in these conditions; consequently, the complexity of these disorders may not be fully understood. Similarly, although important studies have been conducted establishing the pharmacokinetics of exogenous carnitine and short-chain carnitine esters in healthy volunteers, few studies have examined carnitine pharmacokinetics in patient groups. Furthermore, the impact of L-carnitine administration on the kinetics of acylcarnitines has not been established. Given the importance of L-carnitine as well as acylcarnitines in maintaining normal mitochondrial function, this review seeks to examine previous research associated with the homeostasis and pharmacokinetics of L-carnitine and its esters, and highlight potential areas of future research.
Collapse
Affiliation(s)
- Stephanie E Reuter
- School of Pharmacy Medical Sciences, University of South Australia, Adelaide, SA, Australia.
| | | |
Collapse
|
27
|
Purevsuren J, Kobayashi H, Hasegawa Y, Yamada K, Takahashi T, Takayanagi M, Fukao T, Fukuda S, Yamaguchi S. Intracellular in vitro probe acylcarnitine assay for identifying deficiencies of carnitine transporter and carnitine palmitoyltransferase-1. Anal Bioanal Chem 2012; 405:1345-51. [DOI: 10.1007/s00216-012-6532-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 10/10/2012] [Accepted: 10/30/2012] [Indexed: 12/30/2022]
|
28
|
Zomot E, Bahar I. A conformational switch in a partially unwound helix selectively determines the pathway for substrate release from the carnitine/γ-butyrobetaine antiporter CaiT. J Biol Chem 2012; 287:31823-32. [PMID: 22843728 PMCID: PMC3442516 DOI: 10.1074/jbc.m112.397364] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
CaiT is a homotrimeric antiporter that exchanges l-carnitine (CRN) with γ-butyrobetaine (GBB) across the bacterial membrane. Three structures have been resolved to date for CaiT, all in the inward-facing state: CRN-bound (with four CRNs per subunit), GBB-bound (two GBBs per subunit), and apo. One of the reported binding sites is the counterpart of the primary site observed in structurally similar transporters. However, the mechanism and pathway(s) of CRN/GBB unbinding and translocation, or even the ability of the substrates to dislodge from the reported binding sites, are yet to be determined. To shed light on these issues, we performed a total of 1.3 μs of molecular dynamics simulations and examined the dynamics of substrate-bound CaiT structures under different conditions. We find that both CRN and GBB are able to dissociate completely from their primary site into the cytoplasm. Substrate molecules initially located at the secondary sites dissociate even faster (within tens of nanoseconds) into the extra- or intracellular regions. Interestingly, the unbinding pathway from the primary site appears to be dictated by the geometry of the unwound part of the transmembrane (TM) helix 3, mostly around Thr100 therein. Arg262 on TM7, which apparently mimics the role of Na+ in CaiT structural homologues, plays a key role in triggering the dissociation of the substrate away from the primary site and guiding its release to the cytoplasm provided that the unwound part of TM3 switches from a shielding to a yielding pose.
Collapse
Affiliation(s)
- Elia Zomot
- Department of Computational and Systems Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA
| | | |
Collapse
|
29
|
Hu QH, Zhang X, Pan Y, Li YC, Kong LD. Allopurinol, quercetin and rutin ameliorate renal NLRP3 inflammasome activation and lipid accumulation in fructose-fed rats. Biochem Pharmacol 2012; 84:113-25. [DOI: 10.1016/j.bcp.2012.03.005] [Citation(s) in RCA: 134] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Revised: 03/08/2012] [Accepted: 03/08/2012] [Indexed: 12/24/2022]
|
30
|
Mazzini M, Tadros T, Siwik D, Joseph L, Bristow M, Qin F, Cohen R, Monahan K, Klein M, Colucci W. Primary carnitine deficiency and sudden death: in vivo evidence of myocardial lipid peroxidation and sulfonylation of sarcoendoplasmic reticulum calcium ATPase 2. Cardiology 2011; 120:52-8. [PMID: 22116472 DOI: 10.1159/000333127] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Indexed: 11/19/2022]
Abstract
OBJECTIVES Primary carnitine deficiency is an autosomal recessive disorder caused by mutations in the SLC22A5 gene which results in impaired carnitine transport, cytosolic fatty acid accumulation and impaired beta oxidation. The disease is associated with cardiomyopathy and arrhythmias, but the mechanism is unknown. We hypothesized that carnitine deficiency results in increased myocardial oxidative stress. METHODS We evaluated a 22-year-old woman with primary carnitine deficiency and ventricular fibrillation, as well as her first-degree relatives. RESULTS Sequencing of SLC22A5 identified two deleterious mutations (A142S and R488H) and a novel mutation predicted to be a splice variant. Histology demonstrated increased myocardial lipid deposition and swollen mitochondria. Immunohistochemistry demonstrated accumulation of the reactive aldehyde 4-hydroxy-2-nonenal, indicative of increased lipid peroxidation, and sulfonylation of sarcoendoplasmic reticulum calcium ATPase 2 at cysteine 674. CONCLUSIONS These findings suggest that increased oxidant stress may contribute to myocardial dysfunction and arrhythmogenesis in this disorder.
Collapse
Affiliation(s)
- M Mazzini
- Cardiac Electrophysiology Section and Cardiovascular Medicine Section, Boston University Medical Center, Boston, MA 02118, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Saini-Chohan HK, Mitchell RW, Vaz FM, Zelinski T, Hatch GM. Delineating the role of alterations in lipid metabolism to the pathogenesis of inherited skeletal and cardiac muscle disorders: Thematic Review Series: Genetics of Human Lipid Diseases. J Lipid Res 2011; 53:4-27. [PMID: 22065858 DOI: 10.1194/jlr.r012120] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
As the specific composition of lipids is essential for the maintenance of membrane integrity, enzyme function, ion channels, and membrane receptors, an alteration in lipid composition or metabolism may be one of the crucial changes occurring during skeletal and cardiac myopathies. Although the inheritance (autosomal dominant, autosomal recessive, and X-linked traits) and underlying/defining mutations causing these myopathies are known, the contribution of lipid homeostasis in the progression of these diseases needs to be established. The purpose of this review is to present the current knowledge relating to lipid changes in inherited skeletal muscle disorders, such as Duchenne/Becker muscular dystrophy, myotonic muscular dystrophy, limb-girdle myopathic dystrophies, desminopathies, rostrocaudal muscular dystrophy, and Dunnigan-type familial lipodystrophy. The lipid modifications in familial hypertrophic and dilated cardiomyopathies, as well as Barth syndrome and several other cardiac disorders associated with abnormal lipid storage, are discussed. Information on lipid alterations occurring in these myopathies will aid in the design of improved methods of screening and therapy in children and young adults with or without a family history of genetic diseases.
Collapse
Affiliation(s)
- Harjot K Saini-Chohan
- Department of Pharmacology and Therapeutics, Academic Medical Center, Amsterdam, The Netherlands
| | | | | | | | | |
Collapse
|
32
|
Kilic M, Ozgül RK, Coşkun T, Yücel D, Karaca M, Sivri HS, Tokatli A, Sahin M, Karagöz T, Dursun A. Identification of mutations and evaluation of cardiomyopathy in Turkish patients with primary carnitine deficiency. JIMD Rep 2011; 3:17-23. [PMID: 23430869 DOI: 10.1007/8904_2011_36] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2010] [Revised: 03/31/2011] [Accepted: 04/01/2011] [Indexed: 12/13/2022] Open
Abstract
Primary systemic carnitine deficiency (SCD) is an autosomal recessive disorder caused by defective cellular carnitine transport. Patients usually present with predominant metabolic or cardiac manifestations. SCD is caused by mutations in the organic cation/carnitine transporter OCTN2 (SLC22A5) gene. Mutation analysis of SLC22A5 gene was carried out in eight Turkish patients from six families. Six patients presented with signs and symptoms of heart failure, cardiomyopathy, and low plasma carnitine levels, five of them with concurrent anemia. A patient with dilated cardiomyopathy had also facial dysmorphia, microcephaly, and developmental delay. Tandem MS analyses in siblings of the patients revealed two more cases with low plasma carnitine levels. SCD diagnosis was confirmed in these two cases by mutation screening. These two cases were asymptomatic but echocardiography revealed left ventricular dilatation in one of them. Carnitine treatment was started before the systemic signs and symptoms developed in these patients. Mean value of serum carnitine levels of the patients was 2.63±1.92μmol/L at the time of diagnosis. After 1year of treatment, carnitine values increased to 16.62±5.11 (p<0.001) and all responded to carnitine supplementation clinically. Mutation screening of the OCTN2 gene study in the patients revealed two novel (p.G411V, p.G152R), and four previously identified mutations (p.R254X, p.R282X, p.R289X, p.T337Pfs12X). Early recognition and carnitine supplementation can be lifesaving in this inborn error of fatty acid oxidation.
Collapse
Affiliation(s)
- M Kilic
- Department of Pediatrics, Metabolism and Nutrition Unit, Hacettepe University, Ankara, Turkey,
| | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Schiff M, Bénit P, Coulibaly A, Loublier S, El-Khoury R, Rustin P. Mitochondrial response to controlled nutrition in health and disease. Nutr Rev 2011; 69:65-75. [PMID: 21294740 DOI: 10.1111/j.1753-4887.2010.00363.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Mitochondria exert crucial physiological functions that create complex links among nutrition, health, and disease. While mitochondrial dysfunction with subsequent impairment of oxidative phosphorylation (OXPHOS) is the hallmark of the rare inherited OXPHOS diseases, OXPHOS dysfunction also plays a central role in the pathophysiology of common conditions such as type 2 diabetes and various neurodegenerative disorders. Dietary interventions, especially calorie restriction, have been shown to improve the course of these diseases and to extend the lifespan. Few data are available on the impact of nutraceuticals (macronutrients, vitamins, and cofactors) on primary inherited OXPHOS diseases. This review presents recent knowledge about the impact of nutritional modulation on mitochondria and lifespan regulation and about the development of potential treatments for mitochondrial dysfunction diseases.
Collapse
Affiliation(s)
- Manuel Schiff
- Centre de référence Maladies Métaboliques, Hôpital Robert Debré, APHP, Université Paris 7, Faculté de médecine Denis Diderot, IFR02, INSERM, U676, Paris, France.
| | | | | | | | | | | |
Collapse
|
34
|
|
35
|
Furuichi Y, Sugiura T, Kato Y, Shimada Y, Masuda K. OCTN2 is associated with carnitine transport capacity of rat skeletal muscles. Acta Physiol (Oxf) 2010; 200:57-64. [PMID: 20219053 DOI: 10.1111/j.1748-1716.2010.02101.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIM Carnitine plays an essential role in fat oxidation in skeletal muscles; therefore carnitine influx could be crucial for muscle metabolism. OCTN2, a sodium-dependent solute carrier, is assumed to transport carnitine into various organs. However, OCTN2 protein expression and the functional importance of carnitine transport for muscle metabolism have not been studied. We tested the hypothesis that OCTN2 is expressed at higher levels in oxidative muscles than in other muscles, and that the carnitine uptake capacity of skeletal muscles depends on the amount of OCTN2. METHODS Rat hindlimb muscles (soleus, plantaris, and the surface and deep portions of gastrocnemius) were used for Western blotting to detect OCTN2. Tissue carnitine uptake was examined by an integration plot analysis using l-[(3)H]carnitine as a tracer. Tissue carnitine content was determined by enzymatic cycling methods. The percentage of type I fibres was determined by histochemical analysis. RESULTS OCTN2 was detected in all skeletal muscles although the amount was lower than that in the kidney. OCTN2 expression was significantly higher in soleus than in the other skeletal muscles. The amount of OCTN2 was positively correlated with the percentage of type I fibres in hindlimb muscles. The integration plot analysis revealed a positive correlation between the uptake clearance of l-[(3)H]carnitine and the amount of OCTN2 in skeletal muscles. However, the carnitine content in soleus was lower than that in other skeletal muscles. CONCLUSION OCTN2 is functionally expressed in skeletal muscles and is involved in the import of carnitine for fatty acid oxidation, especially in highly oxidative muscles.
Collapse
Affiliation(s)
- Y Furuichi
- Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa-city, Ishikawa, Japan
| | | | | | | | | |
Collapse
|
36
|
Laforêt P, Vianey-Saban C. Disorders of muscle lipid metabolism: diagnostic and therapeutic challenges. Neuromuscul Disord 2010; 20:693-700. [PMID: 20691590 DOI: 10.1016/j.nmd.2010.06.018] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Revised: 06/06/2010] [Accepted: 06/29/2010] [Indexed: 12/31/2022]
Abstract
Disorders of muscle lipid metabolism may involve intramyocellular triglyceride degradation, carnitine uptake, long-chain fatty acids mitochondrial transport, or fatty acid β-oxidation. Three main diseases leading to permanent muscle weakness are associated with severe increased muscle lipid content (lipid storage myopathies): primary carnitine deficiency, neutral lipid storage disease and multiple acyl-CoA dehydrogenase deficiency. A moderate lipidosis may be observed in fatty acid oxidation disorders revealed by rhabdomyolysis episodes such as carnitine palmitoyl transferase II, very-long-chain acyl-CoA dehydrogenase, mitochondrial trifunctional protein deficiencies, and in recently described phosphatidic acid phosphatase deficiency. Respiratory chain disorders and congenital myasthenic syndromes may also be misdiagnosed as fatty acid oxidation disorders due to the presence of secondary muscle lipidosis. The main biochemical tests giving clues for the diagnosis of these various disorders are measurements of blood carnitine and acylcarnitines, urinary organic acid profile, and search for intracytoplasmic lipid on peripheral blood smear (Jordan's anomaly). Genetic analysis orientated by the results of biochemical investigation allows establishing a firm diagnosis. Primary carnitine deficiency and multiple acyl-CoA dehydrogenase deficiency may be treated after supplementation with carnitine, riboflavine and coenzyme Q10. New therapeutic approaches for fatty acid oxidation disorders are currently developed, based on pharmacological treatment with bezafibrate, and specific diets enriched in medium-chain triglycerides or triheptanoin.
Collapse
Affiliation(s)
- Pascal Laforêt
- Centre de Référence de Pathologie Neuromusculaire Paris-Est, Groupe Hospitalier Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France.
| | | |
Collapse
|
37
|
Sayed-Ahmed MM, Al-Shabanah OA, Hafez MM, Aleisa AM, Al-Rejaie SS. Inhibition of gene expression of heart fatty acid binding protein and organic cation/carnitine transporter in doxorubicin cardiomyopathic rat model. Eur J Pharmacol 2010; 640:143-9. [DOI: 10.1016/j.ejphar.2010.05.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2010] [Revised: 04/13/2010] [Accepted: 05/03/2010] [Indexed: 11/17/2022]
|
38
|
Pormsila W, Krähenbühl S, Hauser PC. Determination of carnitine in food and food supplements by capillary electrophoresis with contactless conductivity detection. Electrophoresis 2010; 31:2186-91. [DOI: 10.1002/elps.200900692] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
39
|
Schürch R, Todesco L, Novakova K, Mevissen M, Stieger B, Krähenbühl S. The plasma carnitine concentration regulates renal OCTN2 expression and carnitine transport in rats. Eur J Pharmacol 2010; 635:171-6. [DOI: 10.1016/j.ejphar.2010.02.045] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2009] [Revised: 02/04/2010] [Accepted: 02/24/2010] [Indexed: 01/11/2023]
|
40
|
Tang L, Bai L, Wang WH, Jiang T. Crystal structure of the carnitine transporter and insights into the antiport mechanism. Nat Struct Mol Biol 2010; 17:492-6. [DOI: 10.1038/nsmb.1788] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2009] [Accepted: 02/17/2010] [Indexed: 11/09/2022]
|
41
|
Maternal systemic primary carnitine deficiency uncovered by newborn screening: clinical, biochemical, and molecular aspects. Genet Med 2010; 12:19-24. [PMID: 20027113 DOI: 10.1097/gim.0b013e3181c5e6f7] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Systemic primary carnitine deficiency is an autosomal recessive disorder of the carnitine cycle caused by mutations in the SLC22A5 gene that encodes the carnitine transporter, organic cation transporter. Systemic primary carnitine deficiency typically presents in childhood with either metabolic decompensation or cardiomyopathy. We report five families in which low free carnitine levels in the infants' newborn screening have led to the diagnosis of maternal systemic primary carnitine deficiency. METHODS Blood samples from the infants and /or their family members were used to extract the DNA. The entire coding regions of the SLC22A5 gene were sequenced. The clinical data were obtained from the referring metabolic specialists. RESULT Sequencing the SLC22A5 gene allowed molecular confirmation with identification of three novel mutations: c.1195C>T (p.R399W), c.1324_1325GC>AT (p.A442I), and c.43G>T (p.G15W). All infants were asymptomatic at the time of diagnosis, and one was found to have systemic primary carnitine deficiency. Three mothers are asymptomatic, one had decreased stamina during pregnancy, and one has mild fatigability and developed preeclampsia. DISCUSSION These findings provide further evidence that systemic primary carnitine deficiency presents with a broad clinical spectrum from a metabolic decompensation in infancy to an asymptomatic adult. The maternal systemic primary carnitine deficiency was uncovered by the newborn screening results supporting the previous notion that newborn screening can identify some of the maternal inborn errors of metabolism. It also emphasizes the importance of maternal evaluation after identification of a low free carnitine level in the newborn screening.
Collapse
|
42
|
Sarafoglou K, Tridgell AHC, Bentler K, Redlinger-Grosse K, Berry SA, Schimmenti LA. Cardiac conduction improvement in two heterozygotes for primary carnitine deficiency on L-carnitine supplementation. Clin Genet 2010; 78:191-4. [PMID: 20095986 DOI: 10.1111/j.1399-0004.2009.01368.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Expanded newborn screening (NBS) for free carnitine levels has led to the identification of a larger number of heterozygous infants of undiagnosed mothers affected with systemic primary carnitine deficiency (PCD), which in turn leads to the identification of other undiagnosed heterozygous family members. There is an increasing recognition that individuals heterozygous for mutations of genes involved in fatty acid oxidation (FAO) may become symptomatic under environmental stress (fasting, prolonged exercise and illness). Considering the importance of carnitine in FAO, its role in heart and bowel function and in lipid metabolism, what is still little known is the phenotypic variability, biochemical parameters and clinical course of PCD heterozygotes with consistently low-to-normal levels to low levels of carnitine over a lifetime. We report on three generations of a family--an asymptomatic PCD heterozygous infant identified through NBS that led to the diagnosis of her asymptomatic PCD-affected mother and the heterozygous status of the maternal grandparents who report some cardiac symptoms that overlap with PCD that improved with L-carnitine supplementation.
Collapse
Affiliation(s)
- K Sarafoglou
- Department of Pediatrics, Division of Genetics and Metabolism, Institute of Human Genetics, University of Minnesota, Minneapolis, MN, USA.
| | | | | | | | | | | |
Collapse
|
43
|
Cotton LM, Rodriguez CM, Suzuki K, Orgebin-Crist MC, Hinton BT. Organic cation/carnitine transporter, OCTN2, transcriptional activity is regulated by osmotic stress in epididymal cells. Mol Reprod Dev 2009; 77:114-25. [DOI: 10.1002/mrd.21122] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
44
|
Interaction between pivaloylcarnitine and l-carnitine transport into L6 cells overexpressing hOCTN2. Chem Biol Interact 2009; 180:472-7. [DOI: 10.1016/j.cbi.2009.02.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Revised: 02/25/2009] [Accepted: 02/26/2009] [Indexed: 11/19/2022]
|
45
|
Kano T, Kato Y, Ito K, Ogihara T, Kubo Y, Tsuji A. Carnitine/organic cation transporter OCTN2 (Slc22a5) is responsible for renal secretion of cephaloridine in mice. Drug Metab Dispos 2009; 37:1009-16. [PMID: 19220985 DOI: 10.1124/dmd.108.025015] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Carnitine/organic cation transporter (OCTN) 2 (SLC22A5) plays a pivotal role in renal tubular reabsorption of carnitine, a vitamin-like compound, on apical membranes of proximal tubules, but its role in relation to therapeutic drugs remains to be clarified. The purpose of the present study was to elucidate the involvement of OCTN2 in renal disposition of a beta-lactam antibiotic, cephaloridine (CER), based on experiments with juvenile visceral steatosis (jvs) mice, which have a functional deficiency of the octn2 gene. Renal clearance of CER during constant intravenous infusion in wild-type mice was much higher than could be accounted for by glomerular filtration, but was decreased by increasing the infusion rate with minimal change in kidney-to-plasma concentration ratio, suggesting the existence of saturable transport mechanism(s) across the apical membranes. The plasma concentration profile and kidney-to-plasma concentration ratio after intravenous injection in jvs mice were higher than those in wild-type mice, whereas renal clearance in jvs mice was much lower than that in wild-type mice and could be accounted for by glomerular filtration. Uptake of CER by mouse OCTN2 was shown in Xenopus laevis oocytes expressing mouse OCTN2. The CER transport by OCTN2 exhibited saturation with K(m) of approximately 3 mM, which is similar to the renal CER concentration exhibiting saturation in renal clearance in vivo. The OCTN2-mediated CER transport was inhibited by carnitine and independent of Na(+) replacement in the medium. These results show OCTN2 on apical membranes of proximal tubules plays a major role in renal secretion of CER in mice.
Collapse
Affiliation(s)
- Takashi Kano
- Division of Pharmaceutical Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakumamachi, Kanazawa 920-1192, Japan
| | | | | | | | | | | |
Collapse
|
46
|
Sharma S, Black SM. CARNITINE HOMEOSTASIS, MITOCHONDRIAL FUNCTION, AND CARDIOVASCULAR DISEASE. ACTA ACUST UNITED AC 2009; 6:e31-e39. [PMID: 20648231 DOI: 10.1016/j.ddmec.2009.02.001] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Carnitines are involved in mitochondrial transport of fatty acids and are of critical importance for maintaining normal mitochondrial function. This review summarizes recent experimental and clinical studies showing that mitochondrial dysfunction secondary to a disruption of carnitine homeostasis may play a role in decreased NO signaling and the development of endothelial dysfunction. Future challenges include development of agents that can positively modulate L-carnitine homeostasis which may have high therapeutic potential.
Collapse
Affiliation(s)
- Shruti Sharma
- The Pulmonary Disease Program, Vascular Biology Center, Medical College of Georgia, Augusta, GA 30912
| | | |
Collapse
|
47
|
Knapp AC, Todesco L, Torok M, Beier K, Krähenbühl S. Effect of carnitine deprivation on carnitine homeostasis and energy metabolism in mice with systemic carnitine deficiency. ANNALS OF NUTRITION AND METABOLISM 2008; 52:136-44. [PMID: 18417958 DOI: 10.1159/000127390] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2007] [Accepted: 01/23/2008] [Indexed: 12/16/2022]
Abstract
BACKGROUND/AIMS Juvenile visceral steatosis (jvs-/-) mice lack the activity of the carnitine transporter OCTN2 and are dependent on carnitine substitution. The effects of carnitine deprivation on carnitine homeostasis and energy metabolism are not known in jvs-/- mice. METHODS jvs-/- mice were studied 3, 6 and 10 days after carnitine deprivation, and compared to jvs-/- mice substituted with carnitine, wild-type (jvs+/+) and jvs+/- mice. Carnitine concentrations were assessed radioenzymatically. RESULTS Compared to wild-type mice, carnitine-treated jvs-/- mice had decreased plasma beta-hydroxybutyrate levels and showed hepatic fat accumulation. The carnitine levels in plasma, liver and skeletal muscle were decreased by 58, 16 and 17%, respectively. After ten days of carnitine deprivation, the plasma carnitine concentration had fallen by 87% (to 2.3 mumol/l) and the tissue carnitine levels by approximately 50% compared to carnitine-treated jvs-/- mice. Carnitine deprivation was associated with a further drop in plasma beta-hydroxybutyrate and increased hepatic fat. Skeletal muscle glycogen stores decreased and lactate levels increased with carnitine deprivation, whereas tissue ATP levels were maintained. CONCLUSIONS In jvs-/- mice, tissue carnitine stores are more resistant than carnitine plasma concentrations to carnitine deprivation. Metabolic changes (liver steatosis and loss of muscle glycogen stores) appear also early after carnitine deprivation.
Collapse
Affiliation(s)
- Andrea Caroline Knapp
- Division of Clinical Pharmacology and Toxicology and Department of Research, University Hospital Basel, Basel, Switzerland
| | | | | | | | | |
Collapse
|
48
|
Lal S, Wong ZW, Jada SR, Xiang X, Chen Shu X, Ang PCS, Figg WD, Lee EJ, Chowbay B. Novel SLC22A16 polymorphisms and influence on doxorubicin pharmacokinetics in Asian breast cancer patients. Pharmacogenomics 2008; 8:567-75. [PMID: 17559346 DOI: 10.2217/14622416.8.6.567] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
OBJECTIVE To identify novel polymorphisms in the solute carrier SLC22A16 gene and determine their influence on the pharmacokinetics of doxorubicin and doxorubicinol in Asian breast cancer patients. METHODS SLC22A16 coding regions were screened in a total of 400 healthy subjects belonging to three distinct Asian ethnic groups (Chinese [n = 100], Malays [n = 100] and Indians [n = 100]) and in the Caucasian population (n = 100). Pharmacokinetic parameters of doxorubicin and doxorubicinol were estimated in Asian breast cancer patients undergoing adjuvant chemotherapy to investigate genotype-phenotype correlations. RESULTS Four novel polymorphisms (c.146A>G [exon 2], c.312T>C, c.755T>C [exon 4] and c.1226T>C [exon 5]) were identified. The genotypic frequency of the homozygous c.146GG polymorphism was approximately twofold higher in the healthy Chinese (13%) & Malay (18%) populations compared with the Indian (7%) and Caucasian (9%) populations. The genotypic frequency of the c.1226T>C polymorphism was observed to be significantly higher among the Caucasian (11%) and Indian (8%) study subjects compared with the Chinese (1%) and Malay (1%) ethnic groups (p < 0.005 in each case). Breast cancer patients harboring the 146GG genotype showed a trend towards higher exposure levels to doxorubicin (AUC(0 negative infinity)/dose/body surface area [BSA] [hm(-5)]: 21.6; range: 18.8-27.7) compared with patients with either the reference genotype (AUC(0 negative infinity)/dose/BSA[hm(-5)]: 17.4; range: 8.2-26.3, p = 0.066) or heterozygotes (AUC(0 negative infinity)/dose/BSA[hm(-5)]: 15.4; range: 6.2-38.0, p = 0.055). The exposure levels of doxorubicinol were also higher in patients harboring the variant 146GG genotype (AUC(0 negative infinity)/dose/BSA[hm(-5)]: 13.3; range: 8.8-21.7) when compared with patients harboring the reference genotype (AUC(0 negative infinity)/dose/BSA[hm(-5)]): 9.8; range: 6.1-24.3, p = 0.137) or heterozygotes (AUC(0 negative infinity)/dose/BSA[hm(-5)]: 8.98; range: 3.7-20.6, p = 0.047). CONCLUSION Among the four novel SLC22A16 polymorphisms identified, the c.146A>G and c.1226T>C polymorphisms exhibited interethnic variations in allele and genotype frequencies. This exploratory study suggests that the c.146A>G variation could contribute to the variations in the pharmacokinetics of doxorubicin and doxorubicinol in Asian cancer patients. Further in vitro studies are required to determine the functional impact of these novel polymorphisms on doxorubicin pharmacokinetics in cancer patients.
Collapse
Affiliation(s)
- Suman Lal
- National Cancer Centre, Division of Medical Sciences, 11 Hospital Drive, 169610 Singapore
| | | | | | | | | | | | | | | | | |
Collapse
|
49
|
Vielhaber S, Feistner H, Weis J, Kreuder J, Sailer M, Schröder JM, Kunz WS. Primary carnitine deficiency: adult onset lipid storage myopathy with a mild clinical course. J Clin Neurosci 2008; 11:919-24. [PMID: 15519880 DOI: 10.1016/j.jocn.2003.11.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2003] [Accepted: 11/14/2003] [Indexed: 10/26/2022]
Abstract
We studied two adult patients with myalgia and muscular fatigability during prolonged physical exercise. Serum creatine kinase was increased and muscle biopsy revealed a lipid storage myopathy affecting predominantly the type I fibres. Skeletal muscle carnitine content was reduced to 15% and 21% of the normal mean values, while serum carnitine levels were either normal or decreased. Four months of oral therapy with L-carnitine (3 g per day) resolved the clinical symptoms completely in both patients, and a subsequent muscle biopsy confirmed a marked reduction of lipid storage, along with increased muscle carnitine levels. The analysis of renal carnitine excretion and the exclusion of possible secondary carnitine deficiencies in both patients are compatible with mild defects of the carnitine transporter in one patient and of carnitine biosynthesis in the other. Since myalgia and muscular fatigue are frequent but unspecified complaints of otherwise clinically unremarkable adult patients, it is important to identify myopathies associated with primary carnitine deficiency because they may be amenable to treatment.
Collapse
Affiliation(s)
- S Vielhaber
- Department of Neurology II, Otto-von-Guericke University Magdeburg, University Hospital, Magdeburg, Germany.
| | | | | | | | | | | | | |
Collapse
|
50
|
Cano A, Ovaert C, Vianey-Saban C, Chabrol B. Carnitine membrane transporter deficiency: a rare treatable cause of cardiomyopathy and anemia. Pediatr Cardiol 2008; 29:163-5. [PMID: 17926086 DOI: 10.1007/s00246-007-9051-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2007] [Revised: 07/12/2007] [Accepted: 07/15/2007] [Indexed: 12/30/2022]
Abstract
Carnitine transporter defect is an autosomal recessive disorder caused by mutations in the SLC22A5 gene that encodes the high-affinity carnitine transporter OCTN2. Affected patients can present with predominant metabolic or cardiac manifestations. Early recognition of this disorder in a context of life-threatening cardiac failure and treatment with carnitine can be lifesaving in this inborn error of fatty acid oxidation. Here we describe a boy with a severe cardiomyopathy and severe anemia who improved with carnitine therapy. Physiopathology of anemia, a probably less recognized symptom of carnitine deficiency, is also discussed.
Collapse
Affiliation(s)
- Aline Cano
- Centre de Référence des Maladies Héréditaires du Métabolisme, Hôpital La Timone Enfants, Marseille, France.
| | | | | | | |
Collapse
|