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Fedosov SN, Nexo E, Heegaard CW. Kinetics of Cellular Cobalamin Uptake and Conversion: Comparison of Aquo/Hydroxocobalamin to Cyanocobalamin. Nutrients 2024; 16:378. [PMID: 38337663 PMCID: PMC10857013 DOI: 10.3390/nu16030378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 01/21/2024] [Accepted: 01/25/2024] [Indexed: 02/12/2024] Open
Abstract
Cyanocobalamin (CNCbl) and aquo/hydroxocobalamin (HOCbl) are the forms of vitamin B12 that are most commonly used for supplementation. They are both converted to methylcobalamin (MeCbl) and 5'-deoxyadenosylcobalamin (AdoCbl), which metabolize homocysteine and methylmalonic acid, respectively. Here, we compare the kinetics of uptake and the intracellular transformations of radiolabeled CNCbl vs. HOCbl in HeLa cells. More HOCbl was accumulated over 4-48 h, but further extrapolation indicated similar uptake (>90%) for both vitamin forms. The initially synthesized coenzyme was MeCbl, which noticeably exceeded AdoCbl during 48 h. Yet, the synthesis of AdoCbl accelerated, and the predicted final levels of Cbls were MeCbl ≈ AdoCbl ≈ 40% and HOCbl ≈ 20%. The designed kinetic model revealed the same patterns of the uptake and turnover for CNCbl and HOCbl, apart from two steps. First, the "activating" intracellular processing of the internalized HOCbl was six-fold faster. Second, the detachment rates from the cell surface (when the "excessive" Cbl-molecules were refluxed into the external medium) related as 4:1 for CNCbl vs. HOCbl. This gave a two-fold faster cellular accumulation and processing of HOCbl vs. CNCbl. In medical terms, our data suggest (i) an earlier response to the treatment of Cbl-deficiency with HOCbl, and (ii) the manifestation of a successful treatment initially as a decrease in homocysteine.
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Affiliation(s)
- Sergey N. Fedosov
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark;
- Department of Clinical Medicine/Clinical Biochemistry, Aarhus University Hospital, 8200 Aarhus N, Denmark;
| | - Ebba Nexo
- Department of Clinical Medicine/Clinical Biochemistry, Aarhus University Hospital, 8200 Aarhus N, Denmark;
| | - Christian W. Heegaard
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark;
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Vitamin B12 (Cobalamin): Its Fate from Ingestion to Metabolism with Particular Emphasis on Diagnostic Approaches of Acquired Neonatal/Infantile Deficiency Detected by Newborn Screening. Metabolites 2022; 12:metabo12111104. [DOI: 10.3390/metabo12111104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/07/2022] [Accepted: 11/10/2022] [Indexed: 11/16/2022] Open
Abstract
Acquired vitamin B12 (vB12) deficiency (vB12D) of newborns is relatively frequent as compared with the incidence of inherited diseases included in newborn screening (NBS) of different countries across the globe. Infants may present signs of vB12D before 6 months of age with anemia and/or neurologic symptoms when not diagnosed in asymptomatic state. The possibility of identifying vitamin deficient mothers after their pregnancy during the breastfeeding period could be an additional benefit of the newborn screening. Vitamin supplementation is widely available and easy to administer. However, in many laboratories, vB12D is not included in the national screening program. Optimized screening requires either second-tier testing or analysis of new urine and blood samples combined with multiple clinical and laboratory follow ups. Our scope was to review the physiologic fate of vB12 and the pathobiochemical consequences of vB12D in the human body. Particular emphasis was put on the latest approaches for diagnosis and treatment of vB12D in NBS.
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Effects of vitamin B12 in culture medium for calcified nodule formation by rat dental pulp cells. J Dent Sci 2022. [DOI: 10.1016/j.jds.2022.11.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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A Historical Review of Brain Drug Delivery. Pharmaceutics 2022; 14:pharmaceutics14061283. [PMID: 35745855 PMCID: PMC9229021 DOI: 10.3390/pharmaceutics14061283] [Citation(s) in RCA: 49] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/01/2022] [Accepted: 06/07/2022] [Indexed: 12/13/2022] Open
Abstract
The history of brain drug delivery is reviewed beginning with the first demonstration, in 1914, that a drug for syphilis, salvarsan, did not enter the brain, due to the presence of a blood-brain barrier (BBB). Owing to restricted transport across the BBB, FDA-approved drugs for the CNS have been generally limited to lipid-soluble small molecules. Drugs that do not cross the BBB can be re-engineered for transport on endogenous BBB carrier-mediated transport and receptor-mediated transport systems, which were identified during the 1970s-1980s. By the 1990s, a multitude of brain drug delivery technologies emerged, including trans-cranial delivery, CSF delivery, BBB disruption, lipid carriers, prodrugs, stem cells, exosomes, nanoparticles, gene therapy, and biologics. The advantages and limitations of each of these brain drug delivery technologies are critically reviewed.
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Hinkel J, Schmitt J, Wurm M, Rosenbaum-Fabian S, Schwab KO, Jacobsen DW, Spiekerkoetter U, Fedosov SN, Hannibal L, Grünert SC. Elevated Plasma Vitamin B 12 in Patients with Hepatic Glycogen Storage Diseases. J Clin Med 2020; 9:jcm9082326. [PMID: 32707782 PMCID: PMC7463656 DOI: 10.3390/jcm9082326] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 07/13/2020] [Accepted: 07/17/2020] [Indexed: 12/14/2022] Open
Abstract
Background: Hepatic glycogen storage diseases (GSDs) are inborn errors of metabolism affecting the synthesis or breakdown of glycogen in the liver. This study, for the first time, systematically assessed vitamin B12 status in a large cohort of hepatic GSD patients. Methods: Plasma vitamin B12, total plasma homocysteine (tHcy) and methylmalonic acid concentrations were measured in 44 patients with hepatic GSDs and compared to 42 healthy age- and gender-matched controls. Correlations of vitamin B12 status with different disease markers of GSDs (including liver transaminase activities and triglycerides) as well as the vitamin B12 intake were studied. Results: GSD patients had significantly higher plasma vitamin B12 concentrations than healthy controls (p = 0.0002). Plasma vitamin B12 concentration remained elevated in GSD patients irrespective of vitamin B12 intake. Plasma vitamin B12 concentrations correlated negatively with triglyceride levels, whereas no correlations were detected with liver transaminase activities (GOT and GPT) in GSD patients. Merging biomarker data of healthy controls and GSD patients showed a positive correlation between vitamin B12 status and liver function, which suggests complex biomarker associations. A combined analysis of biomarkers permitted a reliable clustering of healthy controls versus GSD patients. Conclusions: Elevated plasma concentration of vitamin B12 (irrespective of B12 intake) is a common finding in patients with hepatic GSD. The negative correlation of plasma vitamin B12 with triglyceride levels suggests an influence of metabolic control on the vitamin B12 status of GSD patients. Elevated vitamin B12 was not correlated with GOT and GPT in our cohort of GSD patients. Merging of data from healthy controls and GSD patients yielded positive correlations between these biomarkers. This apparent dichotomy highlights the intrinsic complexity of biomarker associations and argues against generalizations of liver disease and elevated vitamin B12 in blood. Further studies are needed to determine whether the identified associations are causal or coincidental, and the possible impact of chronically elevated vitamin B12 on GSD.
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Affiliation(s)
- Julia Hinkel
- Department of General Pediatrics, Adolescent Medicine and Neonatology, Faculty of Medicine, Medical Center—University of Freiburg, 79106 Freiburg, Germany; (J.H.); (J.S.); (S.R.-F.); (K.O.S.); (U.S.)
| | - Johannes Schmitt
- Department of General Pediatrics, Adolescent Medicine and Neonatology, Faculty of Medicine, Medical Center—University of Freiburg, 79106 Freiburg, Germany; (J.H.); (J.S.); (S.R.-F.); (K.O.S.); (U.S.)
| | - Michael Wurm
- Department of General Pediatrics, Adolescent Medicine and Neonatology, Faculty of Medicine, Medical Center—University of Freiburg, 79106 Freiburg, Germany; (J.H.); (J.S.); (S.R.-F.); (K.O.S.); (U.S.)
- Department of Pediatrics, St. Hedwigs Campus, University Children’s Hospital Regensburg, 93049 Regensburg, Germany;
| | - Stefanie Rosenbaum-Fabian
- Department of General Pediatrics, Adolescent Medicine and Neonatology, Faculty of Medicine, Medical Center—University of Freiburg, 79106 Freiburg, Germany; (J.H.); (J.S.); (S.R.-F.); (K.O.S.); (U.S.)
| | - Karl Otfried Schwab
- Department of General Pediatrics, Adolescent Medicine and Neonatology, Faculty of Medicine, Medical Center—University of Freiburg, 79106 Freiburg, Germany; (J.H.); (J.S.); (S.R.-F.); (K.O.S.); (U.S.)
| | - Donald W. Jacobsen
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA;
| | - Ute Spiekerkoetter
- Department of General Pediatrics, Adolescent Medicine and Neonatology, Faculty of Medicine, Medical Center—University of Freiburg, 79106 Freiburg, Germany; (J.H.); (J.S.); (S.R.-F.); (K.O.S.); (U.S.)
| | - Sergey N. Fedosov
- Department of Molecular Biology and Genetics, Aarhus University, DK-8000 Aarhus C, Denmark;
| | - Luciana Hannibal
- Laboratory of Clinical Biochemistry and Metabolism, Department of General Pediatrics, Adolescent Medicine and Neonatology, Medical Center - University of Freiburg, Faculty of Medicine, 79106 Freiburg, Germany
- Correspondence: (L.H.); (S.C.G.)
| | - Sarah C. Grünert
- Department of General Pediatrics, Adolescent Medicine and Neonatology, Faculty of Medicine, Medical Center—University of Freiburg, 79106 Freiburg, Germany; (J.H.); (J.S.); (S.R.-F.); (K.O.S.); (U.S.)
- Correspondence: (L.H.); (S.C.G.)
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Serum Vitamin B12, and Related MTRR and Cubilin Genotypes, Predict Neural Outcomes across the AD Spectrum. Br J Nutr 2020; 124:135-145. [PMID: 32180545 DOI: 10.1017/s0007114520000951] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Epidemiological studies show mixed findings for serum vitamin B12 and both cognitive and regional volume outcomes. No studies to date have comprehensively examined, in non-supplemented individuals, serum B12 level associations with neurodegeneration, hypometabolism, and cognition across the Alzheimer's disease (AD) spectrum. Serum vitamin B12 was assayed from the Alzheimer's Disease Neuroimaging Initiative (ADNI) and the Australian Imaging, Biomarker & Lifestyle Flagship Study of Ageing (AIBL). Voxel-wise analyses regressed B12 levels against regional gray matter (GM) volume and glucose metabolism (p<.05, family-wise corrected). For ADNI GM, there were 39 cognitively normal (CN), 73 mild cognitive impairment (MCI), and 31 AD participants. For AIBL GM, there were 311 CN, 59 MCI, and 31 AD participants. Covariates were age, sex, baseline diagnosis, APOE4 status, and Body Mass Index (BMI). In ADNI, higher B12 was negatively associated with GM in the right precuneus and bilateral frontal gyri. When diagnostic groups were examined separately, only participants with MCI or above an established cutoff for CSF total tau showed such associations. In AIBL, higher B12 was associated with more grey matter in the right amygdala and right superior temporal pole, which largely seemed to be driven by CN participants that constituted most of the sample. Our results suggest that B12 may show different patterns of association based on clinical status and, for ADNI, AD CSF biomarkers. Accounting for these factors may clarify the relationship between B12 with neural outcomes in late-life.
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Basgalupp SP, Siebert M, Ferreira C, Behringer S, Spiekerkoetter U, Hannibal L, Schwartz IVD. Assessment of cellular cobalamin metabolism in Gaucher disease. BMC MEDICAL GENETICS 2020; 21:12. [PMID: 31931749 PMCID: PMC6958775 DOI: 10.1186/s12881-020-0947-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 12/31/2019] [Indexed: 12/13/2022]
Abstract
BACKGROUND Gaucher disease (GD) is a lysosomal disorder caused by biallelic pathogenic mutations in the GBA1 gene that encodes beta-glucosidase (GCase), and more rarely, by a deficiency in the GCase activator, saposin C. Clinically, GD manifests with heterogeneous multiorgan involvement mainly affecting hematological, hepatic and neurological axes. This disorder is divided into three types, based on the absence (type I) or presence and severity (types II and III) of involvement of the central nervous system. At the cellular level, deficiency of GBA1 disturbs lysosomal storage with buildup of glucocerebroside. The consequences of disturbed lysosomal metabolism on biochemical pathways that require lysosomal processing are unknown. Abnormal systemic markers of cobalamin (Cbl, B12) metabolism have been reported in patients with GD, suggesting impairments in lysosomal handling of Cbl or in its downstream utilization events. METHODS Cultured skin fibroblasts from control humans (n = 3), from patients with GD types I (n = 1), II (n = 1) and III (n = 1) and an asymptomatic carrier of GD were examined for their GCase enzymatic activity and lysosomal compartment intactness. Control human and GD fibroblasts were cultured in growth medium with and without 500 nM hydroxocobalamin supplementation. Cellular cobalamin status was examined via determination of metabolomic markers in cell lysate (intracellular) and conditioned culture medium (extracellular). The presence of transcobalamin (TC) in whole cell lysates was examined by Western blot. RESULTS Cultured skin fibroblasts from GD patients exhibited reduced GCase activity compared to healthy individuals and an asymptomatic carrier of GD, demonstrating a preserved disease phenotype in this cell type. The concentrations of total homocysteine (tHcy), methylmalonic acid (MMA), cysteine (Cys) and methionine (Met) in GD cells were comparable to control levels, except in one patient with GD III. The response of these metabolomic markers to supplementation with hydroxocobalamin (HOCbl) yielded variable results. The content of transcobalamin in whole cell lysates was comparable in control human and GD patients. CONCLUSIONS Our results indicate that cobalamin transport and cellular processing pathways are overall protected from lysosomal storage damage in GD fibroblasts. Extending these studies to hepatocytes, macrophages and plasma will shed light on cell- and compartment-specific vitamin B12 metabolism in Gaucher disease.
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Affiliation(s)
- Suelen Porto Basgalupp
- Postgraduate Program in Medical Sciences, Faculty of Medicine, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Basic Research and Advanced Investigations in Neurosciences (BRAIN) Laboratory, Experimental Research Center. Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Brazil
| | - Marina Siebert
- Basic Research and Advanced Investigations in Neurosciences (BRAIN) Laboratory, Experimental Research Center. Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Brazil.,Unit of Laboratorial Research, Experimental Research Center, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Brazil
| | - Charles Ferreira
- Postgraduate Program in Health Sciences, Gynecology and Obstetrics (PPGGO), Faculty of Medicine, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Sidney Behringer
- Laboratory of Clinical Biochemistry and Metabolism, Department of General Pediatrics, Adolescent Medicine and Neonatology, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ute Spiekerkoetter
- Laboratory of Clinical Biochemistry and Metabolism, Department of General Pediatrics, Adolescent Medicine and Neonatology, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Luciana Hannibal
- Laboratory of Clinical Biochemistry and Metabolism, Department of General Pediatrics, Adolescent Medicine and Neonatology, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
| | - Ida Vanessa Doederlein Schwartz
- Postgraduate Program in Medical Sciences, Faculty of Medicine, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. .,Basic Research and Advanced Investigations in Neurosciences (BRAIN) Laboratory, Experimental Research Center. Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Brazil. .,Medical Genetics Service, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Brazil. .,Department of Genetics, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
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Vitamin B12 Status Upon Short-Term Intervention with a Vegan Diet-A Randomized Controlled Trial in Healthy Participants. Nutrients 2019; 11:nu11112815. [PMID: 31752105 PMCID: PMC6893687 DOI: 10.3390/nu11112815] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 11/06/2019] [Accepted: 11/13/2019] [Indexed: 02/07/2023] Open
Abstract
Vegans are at an increased risk for certain micronutrient deficiencies, foremost of vitamin B12. Little is known about the short-term effects of dietary change to plant-based nutrition on vitamin B12 metabolism. Systemic biomarkers of vitamin B12 status, namely, serum vitamin B12 and holotranscobalamin, may respond quickly to a reduced intake of vitamin B12. To test this hypothesis, 53 healthy omnivore subjects were randomized to a controlled unsupplemented vegan diet (VD, n = 26) or meat-rich diet (MD, n = 27) for 4 weeks. Vitamin B12 status was examined by measurement of serum vitamin B12, holotranscobalamin (holo-TC), methylmalonic acid (MMA) and total plasma homocysteine (tHcy). Holo-TC decreased significantly in the VD compared to the MD group after four weeks of intervention, whereas metabolites MMA and tHcy were unaffected. Body weight remained stable in both groups. VD intervention led to a significant reduction of cholesterol intake, and adequate profiles of nutrient and micronutrient status. Lower intake of vitamin B12 was observed in VD, which was mirrored by a lower concentration of serum vitamin B12 and reduced holo-TC after 4 weeks. Plasma holo-TC may be a fast-responding biomarker to monitor adequate supply of vitamin B12 in plant-based individuals.
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Juul CB, Fedosov SN, Nexo E, Heegaard CW. Kinetic analysis of transcellular passage of the cobalamin-transcobalamin complex in Caco-2 monolayers. Mol Biol Cell 2018; 30:467-477. [PMID: 30565973 PMCID: PMC6594447 DOI: 10.1091/mbc.e18-09-0571] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
We suggest a novel kinetic approach to quantifying receptor–ligand interactions via the cellular transport and/or accumulation of the ligand. The system of cobalamin (Cbl, vitamin B12) transport was used as a model, because Cbl is an obligatory cofactor, taken up by animal cells with the help of a transport protein and a membrane receptor. Bovine transcobalamin (bTC) stimulated the cellular accumulation and transcytosis of radioactive [57Co]Cbl in polarized monolayers of Caco-2 cells. The bovine protein was much more efficient than human TC. The transport was inhibited in a dose-dependent manner by the unlabeled bTC-Cbl complex, the ligand-free bTC, and the receptor-associated protein (RAP). This inhibition pattern implied the presence of a megalin-like receptor. Quantitative assessment of kinetic records by the suggested method revealed the apparent concentration of receptors in vitro (≈15 nM), as well as the dissociation constants of bTC–Cbl (Kd = 13 nM) and RAP (Kd = 1.3 nM). The data were used to estimate the effective luminal concentrations of TC-specific receptors in kidneys (3.8 µM) and intestine (50 nM), the tissues resembling polarized Caco-2 cells.
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Affiliation(s)
- Christian B Juul
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark
| | - Sergey N Fedosov
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark
| | - Ebba Nexo
- Department of Clinical Biochemistry, Aarhus University Hospital, 8200 Aarhus N, Denmark
| | - Christian W Heegaard
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark
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