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Murray M, Barlow CK, Blundell S, Buecking M, Gibbon A, Goeckener B, Kaminskas LM, Leitner P, Selby-Pham S, Sinclair A, Waktola HD, Williamson G, Bennett LE. Demonstrating a link between diet, gut microbiota and brain: 14C radioactivity identified in the brain following gut microbial fermentation of 14C-radiolabeled tyrosine in a pig model. Front Nutr 2023; 10:1127729. [PMID: 36969812 PMCID: PMC10033698 DOI: 10.3389/fnut.2023.1127729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 02/21/2023] [Indexed: 03/11/2023] Open
Abstract
BackgroundThere is a need to better understand the relationship between the diet, the gut microbiota and mental health. Metabolites produced when the human gut microbiota metabolize amino acids may enter the bloodstream and have systemic effects. We hypothesize that fermentation of amino acids by a resistant protein-primed gut microbiota could yield potentially toxic metabolites and disturb the availability of neurotransmitter precursors to the brain. However, these mechanisms are challenging to investigate via typical in vitro and clinical methods.MethodsWe developed a novel workflow using 14C radiolabeling to investigate complex nutrient-disease relationships. The first three steps of the workflow are reported here. α-Linolenic acid (ALA) was used as a model nutrient to confirm the efficacy of the workflow, and tyrosine (Tyr) was the test nutrient. 14C-Tyr was administered to male weanling pigs fed a high resistant protein diet, which primed the gut microbiota for fermenting protein. The hypotheses were; (1) that expected biodistribution of 14C-ALA would be observed, and (2) that radioactivity from 14C-Tyr, representing Tyr and other amino acids released from resistant protein following gut microbial fermentation, would be bioavailable to the brain.ResultsRadioactivity from the 14C-ALA was detected in tissues reflecting normal utilization of this essential fatty acid. Radioactivity from the 14C-Tyr was detected in the brain (0.15% of original dose).ConclusionMetabolites of gut-fermented protein and specifically amino acid precursors to neurotransmitters such as tyrosine, are potentially able to affect brain function. By extension, resistant proteins in the diet reaching the gut microbiota, also have potential to release metabolites that can potentially affect brain function. The high specificity of detection of 14C radioactivity demonstrates that the proposed workflow can similarly be applied to understand other key diet and health paradigms.
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Affiliation(s)
- Margaret Murray
- School of Chemistry, Monash University, Clayton, VIC, Australia
- Department of Nutrition, Dietetics and Food, Monash University, Notting Hill, VIC, Australia
| | - Christopher K. Barlow
- Monash Proteomics and Metabolomics Facility and Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Scott Blundell
- Monash Proteomics and Metabolomics Facility and Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Mark Buecking
- Fraunhofer Institute for Molecular Biology and Applied Ecology, Schmallenberg, Germany
| | - Anne Gibbon
- Monash Animal Research Platform, Monash University, Churchill, VIC, Australia
| | - Bernd Goeckener
- Fraunhofer Institute for Molecular Biology and Applied Ecology, Schmallenberg, Germany
| | - Lisa M. Kaminskas
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia
| | - Patricia Leitner
- Fraunhofer Institute for Molecular Biology and Applied Ecology, Schmallenberg, Germany
| | | | - Andrew Sinclair
- Department of Nutrition, Dietetics and Food, Monash University, Notting Hill, VIC, Australia
| | - Habtewold D. Waktola
- School of Chemistry, Monash University, Clayton, VIC, Australia
- Faculty of Health Sciences, School of Pharmacy, Institute of Health, Jimma University, Jimma, Ethiopia
| | - Gary Williamson
- Department of Nutrition, Dietetics and Food, Monash University, Notting Hill, VIC, Australia
| | - Louise E. Bennett
- School of Chemistry, Monash University, Clayton, VIC, Australia
- *Correspondence: Louise E. Bennett,
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Eskildsen M, Hedemann MS, Theil PK, Nørgaard JV. Impact of substituting compound feed with increasing levels of fresh grass-clover on nitrogen metabolism and plasma metabolites of sows. Livest Sci 2020. [DOI: 10.1016/j.livsci.2020.104269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Bongarzone S, Sementa T, Dunn J, Bordoloi J, Sunassee K, Blower PJ, Gee A. Imaging Biotin Trafficking In Vivo with Positron Emission Tomography. J Med Chem 2020; 63:8265-8275. [PMID: 32658479 PMCID: PMC7445742 DOI: 10.1021/acs.jmedchem.0c00494] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The water-soluble vitamin biotin is essential for cellular growth, development, and well-being, but its absorption, distribution, metabolism, and excretion are poorly understood. This paper describes the radiolabeling of biotin with the positron emission tomography (PET) radionuclide carbon-11 ([11C]biotin) to enable the quantitative study of biotin trafficking in vivo. We show that intravenously administered [11C]biotin is quickly distributed to the liver, kidneys, retina, heart, and brain in rodents-consistent with the known expression of the biotin transporter-and there is a surprising accumulation in the brown adipose tissue (BAT). Orally administered [11C]biotin was rapidly absorbed in the small intestine and swiftly distributed to the same organs. Preadministration of nonradioactive biotin inhibited organ uptake and increased excretion. [11C]Biotin PET imaging therefore provides a dynamic in vivo map of transporter-mediated biotin trafficking in healthy rodents. This technique will enable the exploration of biotin trafficking in humans and its use as a research tool for diagnostic imaging of obesity/diabetes, bacterial infection, and cancer.
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Affiliation(s)
- Salvatore Bongarzone
- School of Biomedical Engineering & Imaging Sciences, St Thomas' Hospital, King's College London, London SE1 7EH, United Kingdom
| | - Teresa Sementa
- School of Biomedical Engineering & Imaging Sciences, St Thomas' Hospital, King's College London, London SE1 7EH, United Kingdom
| | - Joel Dunn
- School of Biomedical Engineering & Imaging Sciences, St Thomas' Hospital, King's College London, London SE1 7EH, United Kingdom
| | - Jayanta Bordoloi
- School of Biomedical Engineering & Imaging Sciences, St Thomas' Hospital, King's College London, London SE1 7EH, United Kingdom
| | - Kavitha Sunassee
- School of Biomedical Engineering & Imaging Sciences, St Thomas' Hospital, King's College London, London SE1 7EH, United Kingdom
| | - Philip J Blower
- School of Biomedical Engineering & Imaging Sciences, St Thomas' Hospital, King's College London, London SE1 7EH, United Kingdom
| | - Antony Gee
- School of Biomedical Engineering & Imaging Sciences, St Thomas' Hospital, King's College London, London SE1 7EH, United Kingdom
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Park JY, Han J, Jung HS, Lee G, Kim HJ, Cho GS, Park HJ, Han C, Kim JS, Kim JH. Synthetic probes for in vitro purification and in vivo tracking of hepatocytes derived from human pluripotent stem cells. Biomaterials 2019; 222:119431. [DOI: 10.1016/j.biomaterials.2019.119431] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 07/23/2019] [Accepted: 08/13/2019] [Indexed: 02/06/2023]
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Abstract
This article summarizes the main principles for the appropriate use of laboratory testing in the diagnosis and management of thyroid disorders, as well as controversies that have arisen in association with some of these biochemical tests. To place a test in perspective, its sensitivity and accuracy should be taken into account. Ordering the correct laboratory tests facilitates the early diagnosis of a thyroid disorder and allows for timely and appropriate treatment. This article focuses on a comprehensive update regarding thyroid-stimulating hormone, thyroxine/triiodothyronine, thyroid autoantibodies, thyroglobulin, and calcitonin. Clinical uses of these biochemical tests are outlined.
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Affiliation(s)
- Nazanene H Esfandiari
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan, Domino's Farms Lobby C, Suite 1300, 24 Frank Lloyd Wright Drive, Ann Arbor, MI 48106, USA
| | - Maria Papaleontiou
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan, Domino's Farms Lobby G, Room 1649, 24 Frank Lloyd Wright Drive, Ann Arbor, MI 48106, USA.
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Peyro Saint Paul L, Debruyne D, Bernard D, Mock DM, Defer GL. Pharmacokinetics and pharmacodynamics of MD1003 (high-dose biotin) in the treatment of progressive multiple sclerosis. Expert Opin Drug Metab Toxicol 2016; 12:327-44. [PMID: 26699811 DOI: 10.1517/17425255.2016.1136288] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
INTRODUCTION Multiple sclerosis (MS) is a chronic, potentially highly disabling neurological disorder. No disease-modifying treatments are approved in the progressive and not active forms of the disease. AREAS COVERED High doses of biotin were tested in an open-label pilot study involving 23 patients with progressive MS and reported positive results. A randomized, double-blind, placebo-controlled trial in 154 progressive MS patients confirmed the beneficial effect of MD1003 (high-dose biotin) on reversing or stabilizing disability progression, with a good safety profile. It is proposed that MD1003 in progressive MS 1) increases energy production in demyelinated axons and/or 2) enhances myelin synthesis in oligodendrocytes. Biotin is highly bioavailable; absorption and excretion are rapid. The major route of elimination is urinary excretion. EXPERT OPINION A high oral dose of biotin seems generally well tolerated but a few important safety concerns were identified: 1) teratogenicity in one species and 2) interference with some biotin-based laboratory immunoassays. The animal toxicity data are limited at such high doses. Further preclinical studies would be useful to address the mechanism of action of MD1003. Assessment of clinical benefit duration in responders will be also very important to set. Results of randomized, placebo-controlled trial are reassuring and provide hope for the treatment of progressive MS.
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Affiliation(s)
| | - Danièle Debruyne
- b Pharmacology , Centre Hospitalier Universitaire de Caen , Caen , France
| | - Delphine Bernard
- c MedDay Pharmaceuticals , ICM-Brain and Spine Institute-IPEPs, Groupe Hospitalier Pitié Salpêtrière , Paris , France
| | - Donald M Mock
- d Department of Biochemistry & Molecular Biology and Pediatrics , University of Arkansas for Medical Sciences , Little Rock , AR , USA
| | - Gilles L Defer
- e Neurology , Centre Hospitalier Universitaire de Caen , Caen , France.,f INSERM U 919 , GIP Cyceron , Caen , France
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Minkovsky A, Lee MN, Dowlatshahi M, Angell TE, Mahrokhian LS, Petrides AK, Melanson SEF, Marqusee E, Woodmansee WW. HIGH-DOSE BIOTIN TREATMENT FOR SECONDARY PROGRESSIVE MULTIPLE SCLEROSIS MAY INTERFERE WITH THYROID ASSAYS. AACE Clin Case Rep 2016; 2:e370-e373. [PMID: 27917400 DOI: 10.4158/ep161261.cr] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To review cases and increase awareness in clinicians treating patients who may be taking biotin. METHODS We describe the presentation and workup of a woman with secondary progressive multiple sclerosis on high dose biotin with laboratory studies suggestive of thyrotoxicosis. RESULTS Plasma samples showed laboratory evidence of elevated thyroid hormone levels with elevated free thyroxine >7.8 ng/dl (reference interval (RI) 0.9-1.7 ng/dl) and decreased thyroid stimulating hormone <0.02 uIU/ml (RI 0.50-5.70 uIU/ml). Laboratory values normalized when biotin was withheld prior to repeat testing. CONCLUSIONS Our case report demonstrates that ingestion of high dose biotin in multiple sclerosis patients can cause interference with laboratory assessment of thyroid function. This interference causes laboratory values suggestive of thyrotoxicosis and can lead to unnecessary evaluation. Clinicians should be aware of the risk of laboratory interference in this patient demographic.
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Affiliation(s)
- Alissa Minkovsky
- Department of Pathology, Brigham and Women's Hospital/Harvard Medical School, Boston, MA
| | - Mark N Lee
- Department of Pathology, Brigham and Women's Hospital/Harvard Medical School, Boston, MA
| | - Mitra Dowlatshahi
- Department of Pathology, Brigham and Women's Hospital/Harvard Medical School, Boston, MA
| | - Trevor E Angell
- Department of Medicine, Division of Endocrinology, Diabetes and Hypertension, Brigham and Women's Hospital/Harvard Medical School, Boston, MA
| | - Lilian S Mahrokhian
- Department of Medicine, Brigham and Women's Hospital/Harvard Medical School, Boston, MA
| | - Athena K Petrides
- Department of Pathology, Brigham and Women's Hospital/Harvard Medical School, Boston, MA
| | - Stacy E F Melanson
- Department of Pathology, Brigham and Women's Hospital/Harvard Medical School, Boston, MA
| | - Ellen Marqusee
- Department of Medicine, Division of Endocrinology, Diabetes and Hypertension, Brigham and Women's Hospital/Harvard Medical School, Boston, MA
| | - Whitney W Woodmansee
- Department of Medicine, Division of Endocrinology, Diabetes and Hypertension, Brigham and Women's Hospital/Harvard Medical School, Boston, MA
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Sedel F, Papeix C, Bellanger A, Touitou V, Lebrun-Frenay C, Galanaud D, Gout O, Lyon-Caen O, Tourbah A. High doses of biotin in chronic progressive multiple sclerosis: a pilot study. Mult Scler Relat Disord 2015; 4:159-69. [PMID: 25787192 DOI: 10.1016/j.msard.2015.01.005] [Citation(s) in RCA: 155] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 12/26/2014] [Accepted: 01/12/2015] [Indexed: 12/12/2022]
Abstract
BACKGROUND No drug has been found to have any impact on progressive multiple sclerosis (MS). Biotin is a vitamin acting as a coenzyme for carboxylases involved in key steps of energy metabolism and fatty acids synthesis. Among others, biotin activates acetylCoA carboxylase, a potentially rate-limiting enzyme in myelin synthesis. OBJECTIVES The aim of this pilot study is to assess the clinical efficacy and safety of high doses of biotin in patients suffering from progressive MS. STUDY DESIGN Uncontrolled, non-blinded proof of concept study METHODS 23 consecutive patients with primary and secondary progressive MS originated from three different French MS reference centers were treated with high doses of biotin (100-300mg/day) from 2 to 36 months (mean=9.2 months). Judgement criteria varied according to clinical presentations and included quantitative and qualitative measures. RESULTS In four patients with prominent visual impairment related to optic nerve injury, visual acuity improved significantly. Visual evoked potentials in two patients exhibited progressive reappearance of P100 waves, with normalization of latencies in one case. Proton magnetic resonance spectroscopy (H-MRS) in one case showed a progressive normalization of the Choline/Creatine ratio. One patient with left homonymous hemianopia kept on improving from 2 to 16 months following treatment׳s onset. Sixteen patients out of 18 (89%) with prominent spinal cord involvement were considered as improved as confirmed by blinded review of videotaped clinical examination in 9 cases. In all cases improvement was delayed from 2 to 8 months following treatment׳s onset. CONCLUSIONS These preliminary data suggest that high doses of biotin might have an impact on disability and progression in progressive MS. Two double-blind placebo-controlled trials are on going.
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Affiliation(s)
- Frédéric Sedel
- Neurology Department, AP-HP, Salpêtrière Hospital, Paris, France; Neuro-Metabolic Unit and Reference Center for Lysosomal Diseases, GRC13UPMC, Pierre & Marie Curie University-Paris 6, AP-HP, Salpêtrière Hospital, Paris, France
| | - Caroline Papeix
- Neurology Department, AP-HP, Salpêtrière Hospital, Paris, France
| | | | - Valérie Touitou
- Department of Ophthalmology, AP-HP, Salpêtrière Hospital, Paris, France
| | | | - Damien Galanaud
- Department of Neuroradiology, Pierre & Marie Curie University-Paris 6, Paris, France
| | - Olivier Gout
- Department of Neurology, Fondation Ophtalmologique Adolphe de Rothschild, Paris, France
| | | | - Ayman Tourbah
- Neurology Department, CHU de Reims & Faculté de Médecine de Reims, Champagne-Ardennes University, France; Laboratoire de Psychopathologie et de Neuropsychologie, EA 2027 Paris VIII University, Saint Denis, France.
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Joshi KB, Venkatesh V, Verma S. Biotin interaction with human erythrocytes: contact on membrane surface and formation of self-assembled fibrous structures. Chem Commun (Camb) 2010; 46:3890-2. [DOI: 10.1039/c001924k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Weber W, Bacchus W, Daoud-El Baba M, Fussenegger M. Vitamin H-regulated transgene expression in mammalian cells. Nucleic Acids Res 2007; 35:e116. [PMID: 17827215 PMCID: PMC2034481 DOI: 10.1093/nar/gkm466] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Although adjustable transgene expression systems are considered essential for future therapeutic and biopharmaceutical manufacturing applications, the currently available transcription control modalities all require side-effect-prone inducers such as immunosupressants, hormones and antibiotics for fine-tuning. We have designed a novel mammalian transcription-control system, which is reversibly fine-tuned by non-toxic vitamin H (also referred to as biotin). Ligation of vitamin H, by engineered Escherichia coli biotin ligase (BirA), to a synthetic biotinylation signal fused to the tetracycline-dependent transactivator (tTA), enables heterodimerization of tTA to a streptavidin-linked transrepressor domain (KRAB), thereby abolishing tTA-mediated transactivation of specific target promoters. As heterodimerization of tTA to KRAB is ultimately conditional upon the presence of vitamin H, the system is vitamin H responsive. Transgenic Chinese hamster ovary cells, engineered for vitamin H-responsive gene expression, showed high-level, adjustable and reversible production of a human model glycoprotein in bench-scale culture systems, bioreactor-based biopharmaceutical manufacturing scenarios, and after implantation into mice. The vitamin H-responsive expression systems showed unique band pass filter-like regulation features characterized by high-level expression at low (0–2 nM biotin), maximum repression at intermediate (100–1000 nM biotin), and high-level expression at increased (>100 000 nM biotin) biotin concentrations. Sequential ON-to-OFF-to-ON, ON-to-OFF and OFF-to-ON expression profiles with graded expression transitions can all be achieved by simply increasing the level of a single inducer molecule without exchanging the culture medium. These novel expression characteristics mediated by an FDA-licensed inducer may foster advances in therapeutic cell engineering and manufacturing of difficult-to-produce protein therapeutics.
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Affiliation(s)
- Wilfried Weber
- Institute for Chemical and Bioengineering, ETH Zurich, Wolfgang-Pauli-Strasse 10, HCI F115, CH-8093 Zurich, Switzerland and Institut Universitaire de Technologie, IUTA, Département Génie Biologique, F-69622 Villeurbanne Cedex, France
| | - William Bacchus
- Institute for Chemical and Bioengineering, ETH Zurich, Wolfgang-Pauli-Strasse 10, HCI F115, CH-8093 Zurich, Switzerland and Institut Universitaire de Technologie, IUTA, Département Génie Biologique, F-69622 Villeurbanne Cedex, France
| | - Marie Daoud-El Baba
- Institute for Chemical and Bioengineering, ETH Zurich, Wolfgang-Pauli-Strasse 10, HCI F115, CH-8093 Zurich, Switzerland and Institut Universitaire de Technologie, IUTA, Département Génie Biologique, F-69622 Villeurbanne Cedex, France
| | - Martin Fussenegger
- Institute for Chemical and Bioengineering, ETH Zurich, Wolfgang-Pauli-Strasse 10, HCI F115, CH-8093 Zurich, Switzerland and Institut Universitaire de Technologie, IUTA, Département Génie Biologique, F-69622 Villeurbanne Cedex, France
- *To whom correspondence should be addressed. +41 44 633 34 48+41 44 633 12 34
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Mishra S, Storer MK, Sherwin CMT, Lewis JG. A simple binding assay for the direct determination of biotin in urine. Clin Chim Acta 2005; 360:60-6. [PMID: 15961070 DOI: 10.1016/j.cccn.2005.04.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2001] [Revised: 04/01/2005] [Accepted: 04/01/2005] [Indexed: 11/28/2022]
Abstract
BACKGROUND We have devised a simple assay to detect adequate biotin intake, which uses an alternative configuration from most existing assays. METHODS The assay depends on the competition of streptavidin peroxidase for immobilized biotin or soluble biotin in standards or samples. Immobilized streptavidin peroxidase is detected using tetramethylbenzidine, and the plates are read at 450 nm. The assay was normalised by determining the biotin/creatinine ratio in the urine of healthy adults. Urinary biotin excretion was measured in unsupplemented pregnant women. The half-life of biotin excretion after a single oral supplement was determined for healthy volunteers. RESULTS Urinary biotin excretion in unsupplemented pregnant women was 2.9+/-1.9 micromol/mol creatinine (mean+/-S.D.) and was significantly lower (p<0.001) than those of healthy males and females, which were 9.0+/-5.4 and 7.0+/-2.1 micromol/mol creatinine (mean+/-S.D.), respectively. The half-life of a single oral biotin supplement was 30-40 h, with excretion returning to basal levels at 70 h. CONCLUSION We have devised a novel binding assay for the direct determination of total biotin excretion in urine, which is suitable for routine clinical laboratory. The assay is inexpensive, simple, rapid, and could be fully automated.
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Affiliation(s)
- Suman Mishra
- Steroid Laboratory, Canterbury Health Laboratories, PO Box 151, Christchurch, New Zealand
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Mardach R, Zempleni J, Wolf B, Cannon MJ, Jennings ML, Cress S, Boylan J, Roth S, Cederbaum S, Mock DM. Biotin dependency due to a defect in biotin transport. J Clin Invest 2002; 109:1617-23. [PMID: 12070309 PMCID: PMC151007 DOI: 10.1172/jci13138] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2001] [Accepted: 05/14/2002] [Indexed: 11/17/2022] Open
Abstract
We describe a 3-year-old boy with biotin dependency not caused by biotinidase, holocarboxylase synthetase, or nutritional biotin deficiency. We sought to define the mechanism of his biotin dependency. The child became acutely encephalopathic at age 18 months. Urinary organic acids indicated deficiency of several biotin-dependent carboxylases. Symptoms improved rapidly following biotin supplementation. Serum biotinidase activity and Biotinidase gene sequence were normal. Activities of biotin-dependent carboxylases in PBMCs and cultured skin fibroblasts were normal, excluding biotin holocarboxylase synthetase deficiency. Despite extracellular biotin sufficiency, biotin withdrawal caused recurrent abnormal organic aciduria, indicating intracellular biotin deficiency. Biotin uptake rates into fresh PBMCs from the child and into his PBMCs transformed with Epstein Barr virus were about 10% of normal fresh and transformed control cells, respectively. For fresh and transformed PBMCs from his parents, biotin uptake rates were consistent with heterozygosity for an autosomal recessive genetic defect. Increased biotin breakdown was ruled out, as were artifacts of biotin supplementation and generalized defects in membrane permeability for biotin. These results provide evidence for a novel genetic defect in biotin transport. This child is the first known with this defect, which should now be included in the identified causes of biotin dependency.
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Affiliation(s)
- Rebecca Mardach
- Regional Metabolic Service, Kaiser Permanente, Los Angeles, California, USA
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Rathman SC, Lewis B, McMahon RJ. Acute glucocorticoid treatment increases urinary biotin excretion and serum biotin. Am J Physiol Endocrinol Metab 2002; 282:E643-9. [PMID: 11832368 DOI: 10.1152/ajpendo.00357.2001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous studies have demonstrated that glucocorticoids alter biotin metabolism. To extend these studies, the effect of dexamethasone on biotin pools was analyzed in rats consuming a purified diet containing a more physiological level of dietary biotin intake (0.06 mg/kg). Acute (5 h) dexamethasone administration (0.5 mg/kg) elicited elevated urinary glucose output as well as elevated urinary biotin excretion and serum biotin. Renal and hepatic free biotin was also significantly elevated by acute dexamethasone administration. Chow-fed rats treated with an acute administration of dexamethasone demonstrated significantly elevated urinary glucose excretion, urinary biotin excretion, and serum biotin, but no change in tissue associated biotin was detected. Chronic administration of dexamethasone (0.5 mg/kg ip) over 4 days significantly elevated urinary glucose excretion 42% but had no effect on urinary biotin excretion, serum biotin, or hepatic- or renal-associated free biotin. These results demonstrate the existence of potentially novel regulatory pathways for total biotin pools and the possibility that experimental models with high initial biotin status may mask potentially important regulatory mechanisms.
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Affiliation(s)
- Sara C Rathman
- The Center for Nutritional Science and The Food Science and Human Nutrition Department, University of Florida, Gainesville, Florida 32611, USA
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