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Kurpad AV, Pasanna RM, Hegde SG, Patil M, Mukhopadhyay A, Sachdev HS, Bhat KG, Sivadas A, Devi S. Bioavailability and daily requirement of vitamin B 12 in adult humans: an observational study of its colonic absorption and daily excretion as measured by [ 13C]-cyanocobalamin kinetics. Am J Clin Nutr 2023; 118:1214-1223. [PMID: 38044024 DOI: 10.1016/j.ajcnut.2023.08.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Revised: 08/28/2023] [Accepted: 08/30/2023] [Indexed: 12/05/2023] Open
Abstract
BACKGROUND Clinical and biochemical vitamin B12 (B12) deficiency is lower than anticipated in vegetarians. Extraileal absorption, such as from the colon, as well as reduced daily excretion, may be adaptive mechanisms to maintain B12 homeostasis with marginal intakes. OBJECTIVE To measure the absorption of B12 from the small and large intestine, and its daily rate of excretion from the body, using a [13C]-cyanocobalamin tracer. METHODS Oral B12 bioavailability was measured over 12 h after administration of [13C]-cyanocobalamin tracer (2.5 μg) in normal participants. The colonic B12 bioavailability was evaluated by direct instillation of [13C]-cyanocobalamin (5 μg) into the ascending colon. Bioavailability was calculated from 2-compartmental modeling of the tracer appearance in plasma. The excretion rate of B12 was measured from [13C]-cyanocobalamin elimination from the body over 4 wk after oral dosing (5 μg). RESULTS The oral B12 bioavailability (n = 11) was 63% ± 10% measured over 12 h. A late absorption peak, accounting for 12% of the absorption, was observed after an average lag time of 8.7 h from dosing. The colonic B12 bioavailability (n = 10) was 7% ± 5% over 4 h. The daily B12 excretion rate (n = 4) was 0.7 ± 0.2 μg/d. The minimum daily requirement of B12 in these participants was derived at 1 μg /d. CONCLUSIONS B12 is absorbed in the human colon. This observation confirms the potential contribution of the colon in daily B12 nutriture, and along with a possible lower requirement, could explain the absence of clinical deficiency in populations with marginal B12 intakes. TRIAL REGISTRATION NUMBER This study was registered in Clinical Trials Registry of India (CTRI) with the registration number CTRI/2018/04/012957, available from https://ctri.nic.in/Clinicaltrials/showallp.php?mid1=49319&EncHid=&userName=029108.
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Affiliation(s)
- Anura V Kurpad
- Department of Physiology, St. John's Medical College, Bengaluru, India.
| | - Roshni M Pasanna
- Division of Nutrition, St. John's Research Institute, Bengaluru, India
| | - Shalini G Hegde
- Department of Paediatric Surgery, St. John's Medical College, Bengaluru, India
| | - Mallikarjun Patil
- Department of Gastroenterology, St. John's Medical College, Bengaluru, India
| | | | - Harshpal S Sachdev
- Department of Paediatrics, Sitaram Bhartia Institute of Science and Research, New Delhi, India
| | - Kishor G Bhat
- Division of Nutrition, St. John's Research Institute, Bengaluru, India
| | - Ambily Sivadas
- Division of Nutrition, St. John's Research Institute, Bengaluru, India
| | - Sarita Devi
- Division of Nutrition, St. John's Research Institute, Bengaluru, India.
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Kovatcheva M, Melendez E, Chondronasiou D, Pietrocola F, Bernad R, Caballe A, Junza A, Capellades J, Holguín-Horcajo A, Prats N, Durand S, Rovira M, Yanes O, Stephan-Otto Attolini C, Kroemer G, Serrano M. Vitamin B 12 is a limiting factor for induced cellular plasticity and tissue repair. Nat Metab 2023; 5:1911-1930. [PMID: 37973897 PMCID: PMC10663163 DOI: 10.1038/s42255-023-00916-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 09/27/2023] [Indexed: 11/19/2023]
Abstract
Transient reprogramming by the expression of OCT4, SOX2, KLF4 and MYC (OSKM) is a therapeutic strategy for tissue regeneration and rejuvenation, but little is known about its metabolic requirements. Here we show that OSKM reprogramming in mice causes a global depletion of vitamin B12 and molecular hallmarks of methionine starvation. Supplementation with vitamin B12 increases the efficiency of reprogramming both in mice and in cultured cells, the latter indicating a cell-intrinsic effect. We show that the epigenetic mark H3K36me3, which prevents illegitimate initiation of transcription outside promoters (cryptic transcription), is sensitive to vitamin B12 levels, providing evidence for a link between B12 levels, H3K36 methylation, transcriptional fidelity and efficient reprogramming. Vitamin B12 supplementation also accelerates tissue repair in a model of ulcerative colitis. We conclude that vitamin B12, through its key role in one-carbon metabolism and epigenetic dynamics, improves the efficiency of in vivo reprogramming and tissue repair.
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Affiliation(s)
- Marta Kovatcheva
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain.
| | - Elena Melendez
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Dafni Chondronasiou
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Federico Pietrocola
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Raquel Bernad
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Adrià Caballe
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Alexandra Junza
- Universitat Rovira i Virgili, Department of Electronic Engineering, IISPV, Tarragona, Spain
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
| | - Jordi Capellades
- Universitat Rovira i Virgili, Department of Electronic Engineering, IISPV, Tarragona, Spain
- Institut d'Investigació Sanitària Pere Virgili (IISPV), Metabolomics Platform, Reus, Spain
| | - Adrián Holguín-Horcajo
- Department of Physiological Science, School of Medicine, Universitat de Barcelona (UB), L'Hospitalet de Llobregat, Spain
- Pancreas Regeneration: Pancreatic Progenitors and Their Niche Group, Regenerative Medicine Program, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Spain
| | - Neus Prats
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Sylvere Durand
- Metabolomics and Cell Biology Platforms UMS AMMICa/UMR 1138, Institut Gustave Roussy, Villejuif, France
- Equipe labellisée par la Ligue contre le cancer, Centre de Recherche des Cordeliers, Inserm U1138, Université de Paris, Sorbonne Université, Institut Universitaire de France, Paris, France
| | - Meritxell Rovira
- Department of Physiological Science, School of Medicine, Universitat de Barcelona (UB), L'Hospitalet de Llobregat, Spain
- Pancreas Regeneration: Pancreatic Progenitors and Their Niche Group, Regenerative Medicine Program, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Spain
| | - Oscar Yanes
- Universitat Rovira i Virgili, Department of Electronic Engineering, IISPV, Tarragona, Spain
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
| | - Camille Stephan-Otto Attolini
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Guido Kroemer
- Metabolomics and Cell Biology Platforms UMS AMMICa/UMR 1138, Institut Gustave Roussy, Villejuif, France
- Equipe labellisée par la Ligue contre le cancer, Centre de Recherche des Cordeliers, Inserm U1138, Université de Paris, Sorbonne Université, Institut Universitaire de France, Paris, France
- Institut du Cancer Paris CARPEM, Department of Biology, Hôpital Européen Georges Pompidou, AP-HP, Paris, France
| | - Manuel Serrano
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain.
- Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain.
- Altos Labs, Cambridge Institute of Science, Cambridge, UK.
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Boachie J, Adaikalakoteswari A, Goljan I, Samavat J, Cagampang FR, Saravanan P. Intracellular and Tissue Levels of Vitamin B12 in Hepatocytes Are Modulated by CD320 Receptor and TCN2 Transporter. Int J Mol Sci 2021; 22:3089. [PMID: 33803025 PMCID: PMC8002616 DOI: 10.3390/ijms22063089] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 03/10/2021] [Accepted: 03/14/2021] [Indexed: 11/17/2022] Open
Abstract
The liver mass constitutes hepatocytes expressing receptors for vitamin B12 (B12)-bound transporters in circulation. However, intrahepatic and circulating B12 interrelationship levels remain unclear. We assessed the intracellular B12 levels at various circulating B12 concentrations in human HepG2 cell-line and liver tissue levels of B12 in the C57BL/6 mouse model. In HepG2 cells treated with a range of B12 concentrations, the intracellular and circulatory B12 levels, transcript and protein levels of B12 receptor (CD320) and transporter (TCN2) were determined using immunoassays, qRT-PCR and Western blot, respectively. Similar assessments were done in plasma and liver tissue of C57BL/6 mice, previously fed a diet of either a high or low B12 (30.82 µg B12/kg and 7.49 µg B12/kg, respectively) for 8-10 weeks. The physiological B12 status (0.15-1 nM) resulted in increased levels of intracellular B12 in HepG2 cells compared to supraphysiological levels of B12 (>1 nM). Gene and protein expression of CD320 and TCN2 were also higher at physiological levels of B12. Progressively increasing extracellular B12 to supraphysiological levels led to relative decreased levels of intracellular B12, lower expression of gene and protein levels of CD320 and TCN2. Similar results were observed in liver tissue from mice fed on a low B12 diet verses high B12 diet. These findings suggest that unlike supraphysiological B12, physiological levels of B12 in the extracellular media or circulation accelerates active transport of B12, and expression of CD320 and TCN2, resulting in higher relative uptake of B12 in hepatocytes.
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Affiliation(s)
- Joseph Boachie
- Division of Metabolic and Vascular Health, Warwick Medical School, University of Warwick, Coventry CV2 2DX, UK; (J.B.); (J.S.)
| | - Antonysunil Adaikalakoteswari
- Division of Metabolic and Vascular Health, Warwick Medical School, University of Warwick, Coventry CV2 2DX, UK; (J.B.); (J.S.)
- Department of Biosciences, School of Science and Technology, Nottingham Trent University, Nottingham NG11 8NS, UK
| | - Ilona Goljan
- Diabetes Centre, George Eliot Hospital NHS Trust College Street, Nuneaton CV10 7DJ, UK;
| | - Jinous Samavat
- Division of Metabolic and Vascular Health, Warwick Medical School, University of Warwick, Coventry CV2 2DX, UK; (J.B.); (J.S.)
| | - Felino R. Cagampang
- Institute of Developmental Sciences, University of Southampton, Faculty of Medicine, Southampton General Hospital, Southampton SO16 6YD, UK;
| | - Ponnusamy Saravanan
- Division of Metabolic and Vascular Health, Warwick Medical School, University of Warwick, Coventry CV2 2DX, UK; (J.B.); (J.S.)
- Diabetes Centre, George Eliot Hospital NHS Trust College Street, Nuneaton CV10 7DJ, UK;
- Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry CV2 2DX, UK
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Devi S, Pasanna RM, Shamshuddin Z, Bhat K, Sivadas A, Mandal AK, Kurpad AV. Measuring vitamin B-12 bioavailability with [13C]-cyanocobalamin in humans. Am J Clin Nutr 2020; 112:1504-1515. [PMID: 32844171 DOI: 10.1093/ajcn/nqaa221] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 07/10/2020] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Vitamin B-12 deficiency is widespread in many parts of the world, affecting all age groups and increasing with age. It is primarily due to a low intake of animal source foods or malabsorption. The measurement of bioavailability of vitamin B-12 is etiologically important in deficiency but is limited due to the use of radioactive isotopes like [57Co]- or [14C]-cyanocobalamin. OBJECTIVES The aim of this study was to measure the bioavailability of [13C]-cyanocobalamin in humans and to assess the effect of parenteral replenishment of vitamin B-12 on the bioavailability. METHODS We synthesized a stable isotope-labeled vitamin B-12, [13C]-cyanocobalamin, using Salmonella enterica by providing [13C2]-ethanolamine as a sole carbon source. After purification and mass spectrometry-based characterization, its oral bioavailability was measured in the fasted state with high and low oral doses, before and after parenteral replenishment of vitamin B-12 stores, from the kinetics of its plasma appearance in a 2-compartment model. RESULTS [13C]-cyanocobalamin was completely decyanated to [13C]-methylcobalamin describing metabolic utilization, and its plasma appearance showed early and late absorption phases. At a low dose of 2.3 µg, the mean bioavailability was 46.2 ± 12.8 (%, mean ± SD, n = 11). At a higher dose of 18.3 µg, the mean bioavailability was 7.6 ± 1.7 (%, mean ± SD, n = 4). Parenteral replenishment of the vitamin B-12 store in deficient individuals prior to the measurement resulted in a 1.9-fold increase in bioavailability. CONCLUSIONS Vitamin B-12 bioavailability is dose dependent and at a low dose that approximates the normal daily requirement (46%). The stable isotope method described here could be used to define the etiology of deficiency and to inform the dietary requirement in different physiologic states as well as the dose required for supplementation and food fortification. This trial was registered at the Clinical Trials Registry of India as CTRI/2018/04/012957.
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Affiliation(s)
- Sarita Devi
- Division of Nutrition, St. John's Research Institute, St. John's National Academy of Health Sciences, Bangalore, India
| | - Roshni M Pasanna
- Division of Nutrition, St. John's Research Institute, St. John's National Academy of Health Sciences, Bangalore, India
| | - Zeeshan Shamshuddin
- Division of Nutrition, St. John's Research Institute, St. John's National Academy of Health Sciences, Bangalore, India
| | - Kishor Bhat
- Division of Nutrition, St. John's Research Institute, St. John's National Academy of Health Sciences, Bangalore, India
| | - Ambily Sivadas
- Division of Nutrition, St. John's Research Institute, St. John's National Academy of Health Sciences, Bangalore, India
| | - Amit K Mandal
- Division of Clinical Proteomics, St. John's Research Institute, St. John's National Academy of Health Sciences, Bangalore, India
| | - Anura V Kurpad
- Department of Physiology, St. John's Medical College, St. John's National Academy of Health Sciences, Bangalore, India
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Naik S, Mahalle N, Greibe E, Ostenfeld MS, Heegaard CW, Nexo E, Fedosov SN. Cyano-B12 or Whey Powder with Endogenous Hydroxo-B12 for Supplementation in B12 Deficient Lactovegetarians. Nutrients 2019; 11:nu11102382. [PMID: 31590426 PMCID: PMC6835307 DOI: 10.3390/nu11102382] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 09/18/2019] [Accepted: 09/19/2019] [Indexed: 12/31/2022] Open
Abstract
Lactovegetarians (n = 35) with low vitamin B12 (B12) status were intervened for eight weeks capsules containing cyano-B12 (CN-B12), (2 × 2.8 µg/day), or equivalent doses of endogenous B12 (mainly hydroxo-B12 (HO-B12)) in whey powder. Blood samples were examined at baseline, every second week during the intervention, and two weeks post-intervention. The groups did not differ at baseline in [global median (min/max)] plasma B12 [112(61/185)] pmol/L, holotranscobalamin [20(4/99)] pmol/L, folate [13(11/16)], the metabolites total homocysteine [18(9/52)] µmol/L and methylmalonic acid [0.90(0.28/2.5)] µmol/L, and the combined indicator of B12 status (4cB12) [-1.7(-3.0/-0.33)]. Both supplements caused significant effects, though none of the biomarkers returned to normal values. Total plasma B12 showed a higher increase in the capsule group compared to the whey powder group (p = 0.02). However, the increase of plasma holotranscobalamin (p = 0.06) and the lowering of the metabolites (p > 0.07) were alike in both groups. Thereby, the high total plasma B12 in the capsule group was not mirrored in enhanced B12 metabolism, possibly because the B12 surplus was mainly accumulated on an "inert" carrier haptocorrin, considered to be of marginal importance for tissue delivery of B12. In conclusion, we demonstrate that administration of whey powder (HO-B12) or capsules (CN-B12) equivalent to 5.6 µg of B12 daily for eight weeks similarly improves B12 status but does not normalize it. We document that the results for plasma B12 should be interpreted with caution following administration of CN-B12, since the change is disproportionately high compared to the responses of complementary biomarkers.
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Affiliation(s)
- Sadanand Naik
- Department of Pathology, Deenanath Mangeshkar Hospital and Research Center, Pune, 411004, India.
| | - Namita Mahalle
- Department of Pathology, Deenanath Mangeshkar Hospital and Research Center, Pune, 411004, India.
| | - Eva Greibe
- Department of Clinical Biochemistry and Institute of Clinical Medicine, Aarhus University Hospital, DK-8200 Aarhus N, Denmark.
| | | | - Christian W Heegaard
- Department of Molecular Biology and Genetics, Aarhus University, DK-8000 Aarhus C, Denmark.
| | - Ebba Nexo
- Department of Clinical Biochemistry and Institute of Clinical Medicine, Aarhus University Hospital, DK-8200 Aarhus N, Denmark.
| | - Sergey N Fedosov
- Department of Molecular Biology and Genetics, Aarhus University, DK-8000 Aarhus C, Denmark.
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Mahalle N, Bhide V, Greibe E, Heegaard CW, Nexo E, Fedosov SN, Naik S. Comparative Bioavailability of Synthetic B12 and Dietary Vitamin B12 Present in Cow and Buffalo Milk: A Prospective Study in Lactovegetarian Indians. Nutrients 2019; 11:nu11020304. [PMID: 30717112 PMCID: PMC6412291 DOI: 10.3390/nu11020304] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 01/07/2019] [Accepted: 01/09/2019] [Indexed: 11/16/2022] Open
Abstract
We assessed improvements in the vitamin B12 status of Indian lactovegetarians receiving four weeks supplementation with natural B12 in milk versus cyano-B12 in capsules. Three groups (n = 22, 23, 22) received daily oral doses of cyano-B12 (2 × 0.76 µg) or milk (2 × 200 mL) from a cow or buffalo (amounting to B12 ≈ 2 × 0.76 µg). Their blood was examined at baseline and each following week. The baselines (median (min/max)) indicated a low B12 status: plasma B12 (116(51/314)) pmol/L, holotranscobalamin (holoTC) (30(7/119)) pmol/L, total homocysteine (Hcy) (24(10/118)) µmol/L, methylmalonic acid (MMA) (0.58(0.15/2.2)) µmol/L and combined B12 index (cB12) (-1.32 - (-3.12/+0.29)). Shifts from the baselines (B12, holoTC, cB12) and ratios to the baselines (Hcy, MMA) were analyzed over time. The cyano-B12 treatment gave more total B12 in plasma at week one (+29 pmol/L, p = 0.004) but showed no further increase. Other biomarkers changed more comparably between the three groups (p ≥ 0.05): holoTC showed a transient spike that leveled off, Hcy finally decreased to 0.8 × baseline, while MMA showed marginal changes. The combined indexes improved comparably (p = 0.6) in all groups (+0.2(-0.3/+0.9), p ≤ 0.002). In conclusion, the tested formulations similarly improved B12 status, but did not normalize it.
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Affiliation(s)
- Namita Mahalle
- Department of Pathology, Deenanath Mangeshkar Hospital and Research Center, Pune 411004, India.
| | - Vijayshri Bhide
- Department of Pathology, Deenanath Mangeshkar Hospital and Research Center, Pune 411004, India.
| | - Eva Greibe
- Department of Clinical Biochemistry and Institute of Clinical Medicine, Aarhus University Hospital, DK-8200 Aarhus N, Denmark.
| | - Christian W Heegaard
- Department of Molecular Biology and Genetics, Aarhus University, DK-8000 Aarhus C, Denmark.
| | - Ebba Nexo
- Department of Clinical Biochemistry and Institute of Clinical Medicine, Aarhus University Hospital, DK-8200 Aarhus N, Denmark.
| | - Sergey N Fedosov
- Department of Molecular Biology and Genetics, Aarhus University, DK-8000 Aarhus C, Denmark.
| | - Sadanand Naik
- Department of Pathology, Deenanath Mangeshkar Hospital and Research Center, Pune 411004, India.
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Nymark O, Nexo E, Greibe E. Nutritional 1C Imbalance, B12 Tissue Accumulation, and Pregnancy Outcomes: An Experimental Study in Rats. Nutrients 2018; 10:nu10111579. [PMID: 30373131 PMCID: PMC6265706 DOI: 10.3390/nu10111579] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 10/23/2018] [Accepted: 10/24/2018] [Indexed: 02/05/2023] Open
Abstract
Vitamin B12 deficiency during pregnancy has been associated with poor fetal outcome. Here we investigate the influence of a one-carbon (1C) imbalanced diet (low B12, high folate, high methionine) on maternal B12 status, fetal outcome, B12 distribution, and on the 24-h distribution of synthetic cyano-B12 (CN-B12) and natural hydroxo-B12 (HO-B12). Female Wistar rats were mated while on a 1C balanced (n = 12) or imbalanced diet starting two weeks (n = 10) or four weeks (n = 9) prior to pregnancy and continuing throughout pregnancy. At gestation day 18 (out of 21), all rats received an oral dose of labeled CN-B12 or HO-B12. After 24 h, the rats were sacrificed. Fetuses were inspected, and maternal tissues and fetuses were measured for endogenous and labeled B12. Pregnancy caused a redistribution of B12 from the kidneys to the liver and fetal compartment (uterus, placenta, fetuses). The 1C imbalanced diet reduced maternal kidney B12 and gave rise to lower-weight fetuses with visual malformations. In contrast, fetal B12 did not reflect fetal outcome. This suggests that maternal B12 is more important for fetal outcome than fetal B12. The 24-h distribution of labeled B12 in the rats on the 1C imbalanced diet showed a higher fetal accumulation of CN-B12 than HO-B12, while the opposite was seen in the maternal tissues.
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Affiliation(s)
- Ole Nymark
- Department of Clinical Biochemistry, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200 Aarhus N, Denmark.
| | - Ebba Nexo
- Department of Clinical Biochemistry, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200 Aarhus N, Denmark.
| | - Eva Greibe
- Department of Clinical Biochemistry, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200 Aarhus N, Denmark.
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Differences in Tissue Distribution of Cyano⁻B12 and Hydroxo⁻B12 One Week after Oral Intake: An Experimental Study in Male Wistar Rats. Nutrients 2018; 10:nu10101487. [PMID: 30322035 PMCID: PMC6213052 DOI: 10.3390/nu10101487] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 10/04/2018] [Accepted: 10/10/2018] [Indexed: 12/20/2022] Open
Abstract
Foods contain natural vitamin B12 forms, such as hydroxo–B12 (HO–B12), whereas vitamin pills contain the synthetic cyano–B12 (CN–B12). Recent studies in rats showed different tissue distributions of CN–B12 and HO–B12 24 h after oral administration. Here, we investigate whether these differences are sustained or leveled out with time in both B12-deplete and -replete rats, thereby assessing if the two forms are equally good at maintaining a normal B12 status. Male Wistar rats were fed diets with low (n = 16) or high (n = 12) B12 content for 17 days. At day 10, the rats received a single oral dose of [57Co]-labeled CN–B12 or HO–B12 (n = 6 and n = 8, respectively, in each diet group). The rats were sacrificed on day 17 and endogenous B12 and [57Co]–B12 were measured in liver, kidney, and plasma. We found that the low-B12 diet introduced a B12-deplete state as judged from medians of endogenous B12 compared to rats on a (high-B12 diet): Plasma (565 (1410) pmol/L), liver (28.2 (33.2) pmol/g), and kidneys (123 (1300) pmol/g). One week after oral administration, the labeled B12 was distributed as follows: HO–B12 > CN–B12 (liver) and CN–B12 > HO–B12 (kidneys, plasma). The tissue/plasma ratios showed different equilibriums for labeled CN–B12 and HO–B12 in the B12-deplete and -replete groups. The equilibrium of endogenous B12 resembled [57Co]CN–B12 in replete rats but differed from both [57Co]CN–B12 and [57Co]HO–B12 in deplete rats. The data suggest long-term differences in tissue utilization of the two B12 forms and warrant further studies concerning the possible benefits of consuming HO–B12 instead of CN–B12 in oral B12 replacement.
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Greibe E, Nymark O, Fedosov SN, Heegaard CW, Nexo E. Dietary Intake of Vitamin B12 is Better for Restoring a Low B12 Status Than a Daily High-Dose Vitamin Pill: An Experimental Study in Rats. Nutrients 2018; 10:nu10081096. [PMID: 30111759 PMCID: PMC6115999 DOI: 10.3390/nu10081096] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 08/13/2018] [Accepted: 08/14/2018] [Indexed: 12/14/2022] Open
Abstract
Vitamin B12 (B12) is present in foods of animal origin, and vegans are encouraged to take supplements with synthetic B12 in order to ensure a sufficient uptake. Recent rat studies suggest that natural (hydroxo-B12, HO-B12) and synthetic (cyano-B12, CN-B12) B12 behave differently in the body. Here, we test if a daily vitamin pill matches dietary B12 in ability to restore a low B12 status in rats. B12-depleted male Wistar rats (n = 60) were divided into five groups (n = 12 in each) and subjected to two weeks intervention with various schemes of B12 supplementation. Two “dietary” groups received a low-B12 chow that was fortified with either HO-B12 or CN-B12 providing a continuous supply. Two “pill” groups received a single daily dose of CN-B12, where the vitamin content either matched or exceeded by factor four the provisions for the “dietary” groups. A control group received the low-B12 chow without B12 fortification. B12 was measured in plasma and tissues. Dietary B12 provides 35% more B12 to the tissues than an equivalent single daily dose (p < 0.0001). Natural B12 delivers 25% more B12 to the liver than synthetic B12 (p = 0.0007). A fourfold increase in B12, supplemented as a single daily dose, does not provide any extra B12 to the tissues (p = 0.45). We conclude that dietary B12 is better at rescuing a low B12 status than a daily vitamin pill.
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Affiliation(s)
- Eva Greibe
- Department of Clinical Biochemistry, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200 Aarhus N, Denmark.
| | - Ole Nymark
- Department of Clinical Biochemistry, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200 Aarhus N, Denmark.
| | - Sergey N Fedosov
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10, 8000 Aarhus C, Denmark.
| | - Christian W Heegaard
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10, 8000 Aarhus C, Denmark.
| | - Ebba Nexo
- Department of Clinical Biochemistry, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200 Aarhus N, Denmark.
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10
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Hannibal L, Bolisetty K, Axhemi A, DiBello PM, Quadros EV, Fedosov S, Jacobsen DW. Transcellular transport of cobalamin in aortic endothelial cells. FASEB J 2018; 32:5506-5519. [PMID: 29741927 DOI: 10.1096/fj.201701141rr] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Cobalamin [Cbl (or B12)] deficiency causes megaloblastic anemia and a variety of neuropathies. However, homeostatic mechanisms of cyanocobalamin (CNCbl) and other Cbls by vascular endothelial cells are poorly understood. Herein, we describe our investigation into whether cultured bovine aortic endothelial cells (BAECs) perform transcytosis of B12, namely, the complex formed between serum transcobalamin and B12, designated as holo-transcobalamin (holo-TC). We show that cultured BAECs endocytose [57Co]-CNCbl-TC (source material) via the CD320 receptor. The bound Cbl is transported across the cell both via exocytosis in its free form, [57Co]-CNCbl, and via transcytosis as [57Co]-CNCbl-TC. Transcellular mobilization of Cbl occurred in a bidirectional manner. A portion of the endocytosed [57Co]-CNCbl was enzymatically processed by methylmalonic aciduria combined with homocystinuria type C (cblC) with subsequent formation of hydroxocobalamin, methylcobalamin, and adenosylcobalamin, which were also transported across the cell in a bidirectional manner. This demonstrates that transport mechanisms for Cbl in vascular endothelial cells do not discriminate between various β-axial ligands of the vitamin. Competition studies with apoprotein- and holo-TC and holo-intrinsic factor showed that only holo-TC was effective at inhibiting transcellular transport of Cbl. Incubation of BAECs with a blocking antibody against the extracellular domain of the CD320 receptor inhibited uptake and transcytosis by ∼40%. This study reveals that endothelial cells recycle uncommitted intracellular Cbl for downstream usage by other cell types and suggests that the endothelium is self-sufficient for the specific acquisition and subsequent distribution of circulating B12 via the CD320 receptor. We posit that the endothelial lining of the vasculature is an essential component for the maintenance of serum-tissue homeostasis of B12.-Hannibal, L., Bolisetty, K., Axhemi, A., DiBello, P. M., Quadros, E. V., Fedosov, S., Jacobsen, D. W. Transcellular transport of cobalamin in aortic endothelial cells.
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Affiliation(s)
- Luciana Hannibal
- Laboratory of Clinical Biochemistry and Metabolism, Department for Pediatrics, Medical Center, University of Freiburg, Freiburg, Germany.,Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Keerthana Bolisetty
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Armend Axhemi
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Patricia M DiBello
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Edward V Quadros
- Department of Medicine, State University of New York (SUNY) Downstate Medical Center, Brooklyn, New York, USA; and
| | - Sergey Fedosov
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Donald W Jacobsen
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
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11
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Effect of 8-week oral supplementation with 3-µg cyano-B12 or hydroxo-B12 in a vitamin B12-deficient population. Eur J Nutr 2017; 58:261-270. [PMID: 29209773 PMCID: PMC6424936 DOI: 10.1007/s00394-017-1590-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 11/29/2017] [Indexed: 10/25/2022]
Abstract
PURPOSE We compare the effect of 8-week oral supplementation with cyano-B12 (currently used in vitamin pills) and hydroxo-B12 (predominant form in the diet) in a population with nutritional vitamin B12 deficiency. METHODS Fifty-one healthy Indian adults with baseline serum cobalamin < 200 pmol/L were supplied for 8 weeks with daily oral supplements of 3-µg cyano-B12 (n = 15), 3-µg hydroxo-B12 (n = 16), or a placebo (n = 20). Blood at baseline, and each following week, was examined for total cobalamin, holotranscobalamin, methylmalonic acid, and homocysteine. RESULTS The study groups did not differ at baseline and were characterized by [median (range)] serum cobalamin [128 (68-191) pmol/L], holotranscobalamin [16 (6-41) pmol/L], methylmalonic acid [0.8 (0.3-1.7) µmol/L], homocysteine [17.9 (8.5-100.9) µmol/L], and a combined indicator of B12 status 4cB12 of - 1.65 (- 0.64 to - 4.07). The group supplemented with cyano-B12 showed a higher increase in total serum cobalamin than the group treated with hydroxo-B12, while other biomarkers changed comparably in the two groups. After 8 weeks of treatment, the biomarker values of the supplemented groups (pooled) differed significantly from the placebo group. Yet, the vitamin B12 status was still poor [cobalamin: 168 (87-302) pmol/L; holotranscobalamin: 19 (8-45) pmol/L; methylmalonic acid: 0.7 (0.2-1.7) µmol/L; homocysteine: 17.2 (2.6-96.8) µmol/L; 4cB12 = - 1.34 (- 0.33 to - 3.3)]. CONCLUSION 8-week supplementation with 3-µg cyano-B12 elevated serum cobalamin more than 3 µg hydroxo-B12, but all other biomarkers changed similarly in both groups. Supplementation with 3 µg vitamin B12 did not reverse the low status in individuals with nutritional vitamin B12 deficiency. CLINICAL TRIAL REGISTRY OF INDIA REF/2017/02/013343.
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12
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Kuda-Wedagedara AW, Workinger JL, Nexo E, Doyle RP, Viola-Villegas N. 89Zr-Cobalamin PET Tracer: Synthesis, Cellular Uptake, and Use for Tumor Imaging. ACS OMEGA 2017; 2:6314-6320. [PMID: 29104950 PMCID: PMC5664145 DOI: 10.1021/acsomega.7b01180] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 09/18/2017] [Indexed: 06/07/2023]
Abstract
Vitamin B12, or cobalamin (Cbl), is an essential nutrient. Acquisition, transport, and cellular internalization of Cbl are dependent on specific binding proteins and associated receptors. The circulating transport protein transcobalamin (TC) promotes cellular uptake via binding to specific receptors such as CD320, a receptor upregulated in several cancer cell lines. In this study, we report the successful synthesis of 89Zirconium-labeled Cbl that was derivatized with desferrioxamine (89Zr-Cbl). We document the purity of the tracer and its binding to TC compared with that of unmodified cyano-Cbl (CN-Cbl). In vitro studies employing the CD320 receptor-positive breast cancer cell line MDA-MB-453 showed a 6- to 10-fold greater uptake of 89Zr-Cbl when compared with the uptake in the presence of 200-fold excess of CN-Cbl at 37 °C. We used nude mice with MDA-MB-453 tumors to study the feasibility of employing the tracer to visualize CD320 positive tumors. In vivo positron emission tomography images displayed a clear visualization of the tumor with 1.42 ± 0.48 %ID/g uptake (n = 3) at 4 h after injection (p.i.) with the tracer retained at 48 h p.i. Ex vivo biodistribution studies using 89Zr-Cbl exhibited the highest uptake in kidney and liver at 48 h p.i. Results document the feasibility of synthesizing a Cbl-based tracer suitable for both in vivo and ex vivo studies of Cbl trafficking and with the potential to visualize tumors expressing TC receptors, such as CD320.
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Affiliation(s)
- Akhila
N. W. Kuda-Wedagedara
- Department
of Oncology, Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48202, United States
| | - Jayme L. Workinger
- Department
of Chemistry, Syracuse University, 111 College Place, Syracuse, New York 13102, United States
| | - Ebba Nexo
- Department
of Clinical Biochemistry and Institute of Clinical Medicine, Aarhus University Hospital, Aarhus 8000, Denmark
| | - Robert P. Doyle
- Department
of Chemistry, Syracuse University, 111 College Place, Syracuse, New York 13102, United States
- Department
of Medicine, State University of New York
Upstate Medical University, Syracuse, New York 13102, United States
| | - Nerissa Viola-Villegas
- Department
of Oncology, Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48202, United States
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