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Ebenuwa I, Violet PC, Padayatty SJ, Wang Y, Tu H, Wilkins KJ, Moore DF, Eck P, Schiffmann R, Levine M. Vitamin C Urinary Loss in Fabry Disease: Clinical and Genomic Characteristics of Vitamin C Renal Leak. J Nutr 2023; 153:1994-2003. [PMID: 37229630 PMCID: PMC10375496 DOI: 10.1016/j.tjnut.2022.12.009] [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: 08/25/2022] [Revised: 11/30/2022] [Accepted: 12/08/2022] [Indexed: 03/12/2023] Open
Abstract
BACKGROUND Reduced plasma vitamin C concentrations in chronic diseases may result from abnormal urinary excretion of vitamin C: a renal leak. We hypothesized that vitamin C renal leak may be associated with disease-mediated renal dysregulation, resulting in aberrant vitamin C renal reabsorption and increased urinary loss. OBJECTIVES We investigated the prevalence, clinical characteristics, and genomic associations of vitamin C renal leak in Fabry disease, an X-linked lysosomal disease associated with renal tubular dysfunction and low plasma vitamin C concentrations. METHODS We conducted a non-randomized cross-sectional cohort study of men aged 24-42 y, with Fabry disease (n = 34) and controls without acute or chronic disease (n = 33). To match anticipated plasma vitamin C concentrations, controls were placed on a low-vitamin C diet 3 wk before inpatient admission. To determine the primary outcome of vitamin C renal leak prevalence, subjects were fasted overnight, and matched urine and fasting plasma vitamin C measurements were obtained the following morning. Vitamin C renal leak was defined as presence of urinary vitamin C at plasma concentrations below 38 μM. Exploratory outcomes assessed the association between renal leak and clinical parameters, and genomic associations with renal leak using single nucleotide polymorphisms (SNPs) in the vitamin C transporter SLC23A1. RESULTS Compared with controls, the Fabry cohort had 16-fold higher odds of renal leak (6% vs. 52%; OR: 16; 95% CI: 3.30, 162; P < 0.001). Renal leak was associated with higher protein creatinine ratio (P < 0.01) and lower hemoglobin (P = 0.002), but not estimated glomerular filtration rate (P = 0.54). Renal leak, but not plasma vitamin C, was associated with a nonsynonymous single nucleotide polymorphism in vitamin C transporter SLC23A1 (OR: 15; 95% CI: 1.6, 777; P = 0.01). CONCLUSIONS Increased prevalence of renal leak in adult men with Fabry disease may result from dysregulated vitamin C renal physiology and is associated with abnormal clinical outcomes and genomic variation.
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Affiliation(s)
- Ifechukwude Ebenuwa
- Molecular and Clinical Nutrition Section, Digestive Diseases Branch, Intramural Research Program, National Institute of Diabetes and Digestive and Kidney Diseases National Institutes of Health, Bethesda, MD, USA.
| | - Pierre-Christian Violet
- Molecular and Clinical Nutrition Section, Digestive Diseases Branch, Intramural Research Program, National Institute of Diabetes and Digestive and Kidney Diseases National Institutes of Health, Bethesda, MD, USA
| | - Sebastian J Padayatty
- Molecular and Clinical Nutrition Section, Digestive Diseases Branch, Intramural Research Program, National Institute of Diabetes and Digestive and Kidney Diseases National Institutes of Health, Bethesda, MD, USA
| | - Yaohui Wang
- Molecular and Clinical Nutrition Section, Digestive Diseases Branch, Intramural Research Program, National Institute of Diabetes and Digestive and Kidney Diseases National Institutes of Health, Bethesda, MD, USA
| | - Hongbin Tu
- Molecular and Clinical Nutrition Section, Digestive Diseases Branch, Intramural Research Program, National Institute of Diabetes and Digestive and Kidney Diseases National Institutes of Health, Bethesda, MD, USA
| | - Kenneth J Wilkins
- Biostatistics Program, Office of Clinical Research Support, Office of the Director, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - David F Moore
- Developmental and Metabolic Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda MD, USA
| | - Peter Eck
- Department of Human Nutritional Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Raphael Schiffmann
- Developmental and Metabolic Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda MD, USA
| | - Mark Levine
- Molecular and Clinical Nutrition Section, Digestive Diseases Branch, Intramural Research Program, National Institute of Diabetes and Digestive and Kidney Diseases National Institutes of Health, Bethesda, MD, USA
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Grudlewska-Buda K, Wiktorczyk-Kapischke N, Budzyńska A, Kwiecińska-Piróg J, Przekwas J, Kijewska A, Sabiniarz D, Gospodarek-Komkowska E, Skowron K. The Variable Nature of Vitamin C—Does It Help When Dealing with Coronavirus? Antioxidants (Basel) 2022; 11:antiox11071247. [PMID: 35883738 PMCID: PMC9312329 DOI: 10.3390/antiox11071247] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 06/21/2022] [Accepted: 06/22/2022] [Indexed: 02/06/2023] Open
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is still spreading worldwide. For this reason, new treatment methods are constantly being researched. Consequently, new and already-known preparations are being investigated to potentially reduce the severe course of coronavirus disease 2019 (COVID-19). SARS-CoV-2 infection induces the production of pro-inflammatory cytokines and acute serum biomarkers in the host organism. In addition to antiviral drugs, there are other substances being used in the treatment of COVID-19, e.g., those with antioxidant properties, such as vitamin C (VC). Exciting aspects of the use of VC in antiviral therapy are its antioxidant and pro-oxidative abilities. In this review, we summarized both the positive effects of using VC in treating infections caused by SARS-CoV-2 in the light of the available research. We have tried to answer the question as to whether the use of high doses of VC brings the expected benefits in the treatment of COVID-19 and whether such treatment is the correct therapeutic choice. Each case requires individual assessment to determine whether the positives outweigh the negatives, especially in the light of populational studies concerning the genetic differentiation of genes encoding the solute carriers responsible forVC adsorption. Few data are available on the influence of VC on the course of SARS-CoV-2 infection. Deducing from already-published data, high-dose intravenous vitamin C (HDIVC) does not significantly lower the mortality or length of hospitalization. However, some data prove, among other things, its impact on the serum levels of inflammatory markers. Finally, the non-positive effect of VC administration is mainly neutral, but the negative effect is that it can result in urinary stones or nephropathies.
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Affiliation(s)
- Katarzyna Grudlewska-Buda
- Department of Microbiology, Ludwik Rydygier Collegium Medicum, Nicolaus Copernicus University in Toruń, 85-094 Bydgoszcz, Poland; (K.G.-B.); (N.W.-K.); (A.B.); (J.K.-P.); (J.P.); (E.G.-K.)
| | - Natalia Wiktorczyk-Kapischke
- Department of Microbiology, Ludwik Rydygier Collegium Medicum, Nicolaus Copernicus University in Toruń, 85-094 Bydgoszcz, Poland; (K.G.-B.); (N.W.-K.); (A.B.); (J.K.-P.); (J.P.); (E.G.-K.)
| | - Anna Budzyńska
- Department of Microbiology, Ludwik Rydygier Collegium Medicum, Nicolaus Copernicus University in Toruń, 85-094 Bydgoszcz, Poland; (K.G.-B.); (N.W.-K.); (A.B.); (J.K.-P.); (J.P.); (E.G.-K.)
| | - Joanna Kwiecińska-Piróg
- Department of Microbiology, Ludwik Rydygier Collegium Medicum, Nicolaus Copernicus University in Toruń, 85-094 Bydgoszcz, Poland; (K.G.-B.); (N.W.-K.); (A.B.); (J.K.-P.); (J.P.); (E.G.-K.)
| | - Jana Przekwas
- Department of Microbiology, Ludwik Rydygier Collegium Medicum, Nicolaus Copernicus University in Toruń, 85-094 Bydgoszcz, Poland; (K.G.-B.); (N.W.-K.); (A.B.); (J.K.-P.); (J.P.); (E.G.-K.)
| | - Agnieszka Kijewska
- Department of Immunobiology and Environmental Biology, Institute of Maritime and Tropical Medicine, Medical University of Gdansk, 80-211 Gdansk, Poland;
| | | | - Eugenia Gospodarek-Komkowska
- Department of Microbiology, Ludwik Rydygier Collegium Medicum, Nicolaus Copernicus University in Toruń, 85-094 Bydgoszcz, Poland; (K.G.-B.); (N.W.-K.); (A.B.); (J.K.-P.); (J.P.); (E.G.-K.)
| | - Krzysztof Skowron
- Department of Microbiology, Ludwik Rydygier Collegium Medicum, Nicolaus Copernicus University in Toruń, 85-094 Bydgoszcz, Poland; (K.G.-B.); (N.W.-K.); (A.B.); (J.K.-P.); (J.P.); (E.G.-K.)
- Correspondence: ; Tel.: +48-(52)-585-38-38
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Patti G, Pellegrino C, Ricciardi A, Novara R, Cotugno S, Papagni R, Guido G, Totaro V, De Iaco G, Romanelli F, Stolfa S, Minardi ML, Ronga L, Fato I, Lattanzio R, Bavaro DF, Gualano G, Sarmati L, Saracino A, Palmieri F, Di Gennaro F. Potential Role of Vitamins A, B, C, D and E in TB Treatment and Prevention: A Narrative Review. Antibiotics (Basel) 2021; 10:1354. [PMID: 34827292 PMCID: PMC8614960 DOI: 10.3390/antibiotics10111354] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 10/31/2021] [Accepted: 11/04/2021] [Indexed: 12/26/2022] Open
Abstract
(1) Background: Tuberculosis (TB) is one of the world's top infectious killers, in fact every year 10 million people fall ill with TB and 1.5 million people die from TB. Vitamins have an important role in vital functions, due to their anti-oxidant, pro-oxidant, anti-inflammatory effects and to metabolic functions. The aim of this review is to discuss and summarize the evidence and still open questions regarding vitamin supplementation as a prophylactic measure in those who are at high risk of Mycobacterium tuberculosis (MTB) infection and active TB; (2) Methods: We conducted a search on PubMed, Scopus, Google Scholar, EMBASE, Cochrane Library and WHO websites starting from March 1950 to September 2021, in order to identify articles discussing the role of Vitamins A, B, C, D and E and Tuberculosis; (3) Results: Supplementation with multiple micronutrients (including zinc) rather than vitamin A alone may be more beneficial in TB. The WHO recommend Pyridoxine (vitamin B6) when high-dose isoniazid is administered. High concentrations of vitamin C sterilize drug-susceptible, MDR and extensively drug-resistant MTB cultures and prevent the emergence of drug persisters; Vitamin D suppresses the replication of mycobacterium in vitro while VE showed a promising role in TB management as a result of its connection with oxidative balance; (4) Conclusions: Our review suggests and encourages the use of vitamins in TB patients. In fact, their use may improve outcomes by helping both nutritionally and by interacting directly and/or indirectly with MTB. Several and more comprehensive trials are needed to reinforce these suggestions.
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Affiliation(s)
- Giulia Patti
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro”, 70123 Bari, Italy; (G.P.); (C.P.); (A.R.); (R.N.); (S.C.); (R.P.); (G.G.); (V.T.); (G.D.I.); (R.L.); (D.F.B.); (A.S.); (F.D.G.)
| | - Carmen Pellegrino
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro”, 70123 Bari, Italy; (G.P.); (C.P.); (A.R.); (R.N.); (S.C.); (R.P.); (G.G.); (V.T.); (G.D.I.); (R.L.); (D.F.B.); (A.S.); (F.D.G.)
| | - Aurelia Ricciardi
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro”, 70123 Bari, Italy; (G.P.); (C.P.); (A.R.); (R.N.); (S.C.); (R.P.); (G.G.); (V.T.); (G.D.I.); (R.L.); (D.F.B.); (A.S.); (F.D.G.)
| | - Roberta Novara
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro”, 70123 Bari, Italy; (G.P.); (C.P.); (A.R.); (R.N.); (S.C.); (R.P.); (G.G.); (V.T.); (G.D.I.); (R.L.); (D.F.B.); (A.S.); (F.D.G.)
| | - Sergio Cotugno
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro”, 70123 Bari, Italy; (G.P.); (C.P.); (A.R.); (R.N.); (S.C.); (R.P.); (G.G.); (V.T.); (G.D.I.); (R.L.); (D.F.B.); (A.S.); (F.D.G.)
| | - Roberta Papagni
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro”, 70123 Bari, Italy; (G.P.); (C.P.); (A.R.); (R.N.); (S.C.); (R.P.); (G.G.); (V.T.); (G.D.I.); (R.L.); (D.F.B.); (A.S.); (F.D.G.)
| | - Giacomo Guido
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro”, 70123 Bari, Italy; (G.P.); (C.P.); (A.R.); (R.N.); (S.C.); (R.P.); (G.G.); (V.T.); (G.D.I.); (R.L.); (D.F.B.); (A.S.); (F.D.G.)
| | - Valentina Totaro
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro”, 70123 Bari, Italy; (G.P.); (C.P.); (A.R.); (R.N.); (S.C.); (R.P.); (G.G.); (V.T.); (G.D.I.); (R.L.); (D.F.B.); (A.S.); (F.D.G.)
| | - Giuseppina De Iaco
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro”, 70123 Bari, Italy; (G.P.); (C.P.); (A.R.); (R.N.); (S.C.); (R.P.); (G.G.); (V.T.); (G.D.I.); (R.L.); (D.F.B.); (A.S.); (F.D.G.)
| | - Federica Romanelli
- Microbiology and Virology Unit, University of Bari, University Hospital Policlinico, 70124 Bari, Italy; (F.R.); (S.S.); (L.R.)
| | - Stefania Stolfa
- Microbiology and Virology Unit, University of Bari, University Hospital Policlinico, 70124 Bari, Italy; (F.R.); (S.S.); (L.R.)
| | - Maria Letizia Minardi
- Infectious Diseases Clinic, University Hospital “Tor Vergata”, Department of Systems Medicine, University of Rome Tor Vergata, 00173 Rome, Italy; (M.L.M.); (I.F.); (L.S.)
| | - Luigi Ronga
- Microbiology and Virology Unit, University of Bari, University Hospital Policlinico, 70124 Bari, Italy; (F.R.); (S.S.); (L.R.)
| | - Ilenia Fato
- Infectious Diseases Clinic, University Hospital “Tor Vergata”, Department of Systems Medicine, University of Rome Tor Vergata, 00173 Rome, Italy; (M.L.M.); (I.F.); (L.S.)
| | - Rossana Lattanzio
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro”, 70123 Bari, Italy; (G.P.); (C.P.); (A.R.); (R.N.); (S.C.); (R.P.); (G.G.); (V.T.); (G.D.I.); (R.L.); (D.F.B.); (A.S.); (F.D.G.)
| | - Davide Fiore Bavaro
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro”, 70123 Bari, Italy; (G.P.); (C.P.); (A.R.); (R.N.); (S.C.); (R.P.); (G.G.); (V.T.); (G.D.I.); (R.L.); (D.F.B.); (A.S.); (F.D.G.)
| | - Gina Gualano
- National Institute for Infectious Diseases “L. Spallanzani” IRCCS, 00161 Rome, Italy;
| | - Loredana Sarmati
- Infectious Diseases Clinic, University Hospital “Tor Vergata”, Department of Systems Medicine, University of Rome Tor Vergata, 00173 Rome, Italy; (M.L.M.); (I.F.); (L.S.)
| | - Annalisa Saracino
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro”, 70123 Bari, Italy; (G.P.); (C.P.); (A.R.); (R.N.); (S.C.); (R.P.); (G.G.); (V.T.); (G.D.I.); (R.L.); (D.F.B.); (A.S.); (F.D.G.)
| | - Fabrizio Palmieri
- National Institute for Infectious Diseases “L. Spallanzani” IRCCS, 00161 Rome, Italy;
| | - Francesco Di Gennaro
- Clinic of Infectious Diseases, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro”, 70123 Bari, Italy; (G.P.); (C.P.); (A.R.); (R.N.); (S.C.); (R.P.); (G.G.); (V.T.); (G.D.I.); (R.L.); (D.F.B.); (A.S.); (F.D.G.)
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Tsiaoussis GI, Christaki E, Apidianakis Y. I Can C Clearly Now: How EPEC Inhibits Gut Vitamin C Transport by Dysregulating SVCT. Dig Dis Sci 2021; 66:2140-2142. [PMID: 32918648 PMCID: PMC7486154 DOI: 10.1007/s10620-020-06594-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/27/2020] [Indexed: 12/09/2022]
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Vitamin C Transporters and Their Implications in Carcinogenesis. Nutrients 2020; 12:nu12123869. [PMID: 33352824 PMCID: PMC7765979 DOI: 10.3390/nu12123869] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 12/11/2020] [Accepted: 12/15/2020] [Indexed: 02/06/2023] Open
Abstract
Vitamin C is implicated in various bodily functions due to its unique properties in redox homeostasis. Moreover, vitamin C also plays a great role in restoring the activity of 2-oxoglutarate and Fe2+ dependent dioxygenases (2-OGDD), which are involved in active DNA demethylation (TET proteins), the demethylation of histones, and hypoxia processes. Therefore, vitamin C may be engaged in the regulation of gene expression or in a hypoxic state. Hence, vitamin C has acquired great interest for its plausible effects on cancer treatment. Since its conceptualization, the role of vitamin C in cancer therapy has been a controversial and disputed issue. Vitamin C is transferred to the cells with sodium dependent transporters (SVCTs) and glucose transporters (GLUT). However, it is unknown whether the impaired function of these transporters may lead to carcinogenesis and tumor progression. Notably, previous studies have identified SVCTs’ polymorphisms or their altered expression in some types of cancer. This review discusses the potential effects of vitamin C and the impaired SVCT function in cancers. The variations in vitamin C transporter genes may regulate the active transport of vitamin C, and therefore have an impact on cancer risk, but further studies are needed to thoroughly elucidate their involvement in cancer biology.
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Multiple genome analyses reveal key genes in Vitamin C and Vitamin D synthesis and transport pathways are shared. Sci Rep 2019; 9:16811. [PMID: 31727908 PMCID: PMC6856197 DOI: 10.1038/s41598-019-53074-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 10/24/2019] [Indexed: 02/06/2023] Open
Abstract
Vitamin C (VC) and vitamin D (VD) have been widely used as the dietary supplements and in treatment of diseases both independently and in combination. Whether there is a connection between their pathways is critical for their therapeutic applications. Using whole-genome expression profiles, we performed multiple measures of associations, networks, eQTL mappings and expressions of key genes of interest in VC and VD functions. Several key genes in their pathways were found to be associated. Gc and Rgn play important roles connecting VC and VD pathways in mice. The r values of expression levels between Gc and Rgn in mouse spleen, liver, lung, and kidney are 0.937, 0.558, 0.901, and 0.617, respectively. The expression QTLs of Gc and Rgn are mapped onto the same locations, i.e., 68-76 MB in chromosome 7 and 26-36 MB in chromosome 9. In humans, there are positive correlations between CYP27B1 and SLC23A1 expression levels in kidney (r = 0.733) and spleen (r = 0.424). SLC23A2 and RXRA are minimally associated in both mouse and human. These data indicate that pathways of VC and VD are not independent but affect each other, and this effect is different between mice and humans during VC and VD synthesis and transportation.
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Guest NS, Horne J, Vanderhout SM, El-Sohemy A. Sport Nutrigenomics: Personalized Nutrition for Athletic Performance. Front Nutr 2019; 6:8. [PMID: 30838211 PMCID: PMC6389634 DOI: 10.3389/fnut.2019.00008] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 01/18/2019] [Indexed: 12/14/2022] Open
Abstract
An individual's dietary and supplement strategies can influence markedly their physical performance. Personalized nutrition in athletic populations aims to optimize health, body composition, and exercise performance by targeting dietary recommendations to an individual's genetic profile. Sport dietitians and nutritionists have long been adept at placing additional scrutiny on the one-size-fits-all general population dietary guidelines to accommodate various sporting populations. However, generic "one-size-fits-all" recommendations still remain. Genetic differences are known to impact absorption, metabolism, uptake, utilization and excretion of nutrients and food bioactives, which ultimately affects a number of metabolic pathways. Nutrigenomics and nutrigenetics are experimental approaches that use genomic information and genetic testing technologies to examine the role of individual genetic differences in modifying an athlete's response to nutrients and other food components. Although there have been few randomized, controlled trials examining the effects of genetic variation on performance in response to an ergogenic aid, there is a growing foundation of research linking gene-diet interactions on biomarkers of nutritional status, which impact exercise and sport performance. This foundation forms the basis from which the field of sport nutrigenomics continues to develop. We review the science of genetic modifiers of various dietary factors that impact an athlete's nutritional status, body composition and, ultimately athletic performance.
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Affiliation(s)
- Nanci S Guest
- Department of Nutritional Sciences, University of Toronto, Toronto, ON, Canada.,Nutrigenomix Inc., Toronto, ON, Canada
| | - Justine Horne
- Department of Health and Rehabilitation Sciences, University of Western Ontario, London, ON, Canada
| | - Shelley M Vanderhout
- Department of Nutritional Sciences, University of Toronto, Toronto, ON, Canada.,Nutrigenomix Inc., Toronto, ON, Canada
| | - Ahmed El-Sohemy
- Department of Nutritional Sciences, University of Toronto, Toronto, ON, Canada.,Nutrigenomix Inc., Toronto, ON, Canada
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Ravindran RD, Sundaresan P, Krishnan T, Vashist P, Maraini G, Saravanan V, Chakravarthy U, Smeeth L, Nitsch D, Young IS, Fletcher AE. Genetic variants in a sodium-dependent vitamin C transporter gene and age-related cataract. Br J Ophthalmol 2018; 103:1223-1227. [PMID: 30442817 PMCID: PMC6709767 DOI: 10.1136/bjophthalmol-2018-312257] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 10/01/2018] [Accepted: 10/17/2018] [Indexed: 12/02/2022]
Abstract
Background Cataract is a major health burden in many countries and a significant problem in India. While observational studies show lower cataract risk with increasing dietary or plasma vitamin C, randomised controlled trials of supplements have been negative. Genetic variants in vitamin C transporter proteins (SLC23A1), especially rs33972313, may provide evidence on a causal association of vitamin C with cataract. Methods We used data from a randomly selected population-based study in people aged 60 years and above in north and south India. Of 7518 sampled, 5428 (72%) were interviewed for socioeconomic and lifestyle factors, attended hospital for lens imaging and blood collection and were subsequently genotyped for rs33972313 and rs6596473. Mixed or pure types of cataract were graded by the Lens Opacity Classification System III as nuclear (2404), cortical (494) or posterior subcapsular cataract (PSC) (1026); 1462 had no significant cataract and no history of cataract surgery and 775 had bilateral aphakia/pseudophakia. Results rs33972313 was associated with cortical (OR 2.16; 95% CI 1.34 to 3.49, p=0.002) and PSC (OR 1.68; 95% CI 1.06 to 2.65, p=0.03) but not with nuclear cataract. In analyses of pure cataracts, associations were found only between rs33972313 and pure cortical cataracts (OR 2.29; 95% CI 1.12 to 4.65, p=0.03) and with a standardised cortical opacity score. There was no association with rs6596473 and any cataract outcomes. Conclusions Using an established genetic variant as a proxy for lifetime ascorbate concentrations, our results support a causal association of vitamin C with cataract.
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Affiliation(s)
| | - Periasamy Sundaresan
- Department of Genetics, Dr.G.Venkataswamy Eye Research Institute, Aravind Medical Research Foundation, Madurai, India
| | | | - Praveen Vashist
- Community Ophthalmology Department, Dr.Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, Delhi, India
| | - Giovanni Maraini
- Dipartimento di Scienze Otorino-Odonto-Oftalmologiche e Cervico Facciali, Universitá degli Studi di Parma, Parma, Italy
| | - Vijayan Saravanan
- Department of Genetics, Dr.G.Venkataswamy Eye Research Institute, Aravind Medical Research Foundation, Madurai, India
| | | | - Liam Smeeth
- Faculty of Epidemiology & Population Health, London School of Hygiene & Tropical Medicine, London, UK
| | - Dorothea Nitsch
- Faculty of Epidemiology & Population Health, London School of Hygiene & Tropical Medicine, London, UK
| | - Ian S Young
- Centre for Public Health, Queen's University Belfast, Belfast, UK
| | - Astrid E Fletcher
- Faculty of Epidemiology & Population Health, London School of Hygiene & Tropical Medicine, London, UK
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Vitamin C Potentiates the Killing of Mycobacterium tuberculosis by the First-Line Tuberculosis Drugs Isoniazid and Rifampin in Mice. Antimicrob Agents Chemother 2018; 62:AAC.02165-17. [PMID: 29298757 DOI: 10.1128/aac.02165-17] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 12/04/2017] [Indexed: 02/01/2023] Open
Abstract
The treatment of drug-susceptible tuberculosis (TB) is long and cumbersome. Mismanagement of TB treatment can lead to the emergence of drug resistance in patients, so shortening the treatment duration could significantly improve TB chemotherapy and prevent the development of drug resistance. We previously discovered that high concentrations of vitamin C sterilize cultures of drug-susceptible and drug-resistant Mycobacterium tuberculosis Here, we tested subinhibitory concentration of vitamin C in combination with TB drugs against M. tuberculosisin vitro and in a mouse model of M. tuberculosis infection. In vivo, we showed that the vitamin C level in mouse serum can be increased by intraperitoneal injection of vitamin C to reach vitamin C levels close to the concentrations required for activity in vitro Although vitamin C had no activity by itself in M. tuberculosis-infected mice, the combination of vitamin C with the first-line TB drugs isoniazid and rifampin reduced the bacterial burden in the lungs of M. tuberculosis-infected mice faster than isoniazid and rifampin combined in two independent experiments. These experiments suggest that the addition of vitamin C to first-line TB drugs could shorten TB treatment. Vitamin C, an inexpensive and nontoxic compound, could easily be added to the TB pharmacopeia to substantially improve chemotherapy outcome, which would have a significant impact on the worldwide TB community.
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10
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Wohlrab C, Phillips E, Dachs GU. Vitamin C Transporters in Cancer: Current Understanding and Gaps in Knowledge. Front Oncol 2017; 7:74. [PMID: 28484682 PMCID: PMC5402541 DOI: 10.3389/fonc.2017.00074] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 04/06/2017] [Indexed: 11/14/2022] Open
Abstract
Sufficient uptake and whole body distribution of vitamin C (ascorbate) is essential for many biochemical processes, including some that are vital for tumor growth and spread. Uptake of ascorbate into cancer cells is modulated by availability, tumor blood flow, tissue diffusion parameters, and ascorbate transport proteins. Uptake into cells is mediated by two families of transport proteins, namely, the solute carrier gene family 23, consisting of sodium-dependent vitamin C transporters (SVCTs) 1 and 2, and the SLC2 family of glucose transporters (GLUTs). GLUTs transport the oxidized form of the vitamin, dehydroascorbate (DHA), which is present at negligible to low physiological levels. SVCT1 and 2 are capable of accumulating ascorbate against a concentration gradient from micromolar concentrations outside to millimolar levels inside of cells. Investigating the expression and regulation of SVCTs in cancer has only recently started to be included in studies focused on the role of ascorbate in tumor formation, progression, and response to therapy. This review gives an overview of the current, limited knowledge of ascorbate transport across membranes, as well as tissue distribution, gene expression, and the relevance of SVCTs in cancer. As tumor ascorbate accumulation may play a role in the anticancer activity of high dose ascorbate treatment, further research into ascorbate transport in cancer tissue is vital.
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Affiliation(s)
- Christina Wohlrab
- Mackenzie Cancer Research Group, Department of Pathology, University of Otago, Christchurch, New Zealand
| | - Elisabeth Phillips
- Mackenzie Cancer Research Group, Department of Pathology, University of Otago, Christchurch, New Zealand
| | - Gabi U Dachs
- Mackenzie Cancer Research Group, Department of Pathology, University of Otago, Christchurch, New Zealand
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11
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Rahman F, Bordignon B, Culerrier R, Peiretti F, Spicuglia S, Djabali M, Landrier JF, Fontes M. Ascorbic acid drives the differentiation of mesoderm-derived embryonic stem cells. Involvement of p38 MAPK/CREB and SVCT2 transporter. Mol Nutr Food Res 2017; 61. [DOI: 10.1002/mnfr.201600506] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Revised: 10/28/2016] [Accepted: 11/03/2016] [Indexed: 11/10/2022]
Affiliation(s)
- Fryad Rahman
- NORT. UMR INSERM 1062, INRA 1260; Aix-Marseille University; Marseille Cedex 5 France
- Department of Biology, Faculty of Science; University of Sulaimani; Sulaimani Kurdistan Region Iraq
| | - Benoit Bordignon
- NORT. UMR INSERM 1062, INRA 1260; Aix-Marseille University; Marseille Cedex 5 France
| | - Raphael Culerrier
- CNRS-UMR 5088/University of Toulouse-3; Université-Paul-Sabatier; Toulouse Cedex France
| | - Franck Peiretti
- NORT. UMR INSERM 1062, INRA 1260; Aix-Marseille University; Marseille Cedex 5 France
| | | | - Malek Djabali
- CNRS-UMR 5088/University of Toulouse-3; Université-Paul-Sabatier; Toulouse Cedex France
| | | | - Michel Fontes
- NORT. UMR INSERM 1062, INRA 1260; Aix-Marseille University; Marseille Cedex 5 France
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12
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Padayatty SJ, Levine M. Vitamin C: the known and the unknown and Goldilocks. Oral Dis 2016; 22:463-93. [PMID: 26808119 DOI: 10.1111/odi.12446] [Citation(s) in RCA: 376] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 01/08/2016] [Indexed: 12/11/2022]
Abstract
Vitamin C (Ascorbic Acid), the antiscorbutic vitamin, cannot be synthesized by humans and other primates, and has to be obtained from diet. Ascorbic acid is an electron donor and acts as a cofactor for fifteen mammalian enzymes. Two sodium-dependent transporters are specific for ascorbic acid, and its oxidation product dehydroascorbic acid is transported by glucose transporters. Ascorbic acid is differentially accumulated by most tissues and body fluids. Plasma and tissue vitamin C concentrations are dependent on amount consumed, bioavailability, renal excretion, and utilization. To be biologically meaningful or to be clinically relevant, in vitro and in vivo studies of vitamin C actions have to take into account physiologic concentrations of the vitamin. In this paper, we review vitamin C physiology; the many phenomena involving vitamin C where new knowledge has accrued or where understanding remains limited; raise questions about the vitamin that remain to be answered; and explore lines of investigations that are likely to be fruitful.
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Affiliation(s)
- S J Padayatty
- Molecular and Clinical Nutrition Section, Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - M Levine
- Molecular and Clinical Nutrition Section, Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
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13
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Shaghaghi MA, Kloss O, Eck P. Genetic Variation in Human Vitamin C Transporter Genes in Common Complex Diseases. Adv Nutr 2016; 7:287-98. [PMID: 26980812 PMCID: PMC4785466 DOI: 10.3945/an.115.009225] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Adequate plasma, cellular, and tissue vitamin C concentrations are required for maintaining optimal health through suppression of oxidative stress and optimizing functions of certain enzymes that require vitamin C as a cofactor. Polymorphisms in the vitamin C transporter genes, compromising genes encoding sodium-dependent ascorbate transport proteins, and also genes encoding facilitative transporters of dehydroascorbic acid, are associated with plasma and tissue cellular ascorbate status and hence cellular redox balance. This review summarizes our current knowledge of the links between variations in vitamin C transporter genes and common chronic diseases. We conclude that emerging genetic knowledge has a good likelihood of defining future personalized dietary recommendations and interventions; however, further validations through biological studies as well as controlled dietary trials are required to identify predictive and actionable genetic biomarkers. We further advocate the need to consider genetic variation of vitamin C transporters in future clinical and epidemiologic studies on common complex diseases.
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Affiliation(s)
| | | | - Peter Eck
- Human Nutritional Sciences, University of Manitoba, Winnipeg, Canada
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14
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Distribution of vitamin C is tissue specific with early saturation of the brain and adrenal glands following differential oral dose regimens in guinea pigs. Br J Nutr 2015; 113:1539-49. [PMID: 25865869 DOI: 10.1017/s0007114515000690] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Vitamin C (VitC) deficiency is surprisingly common in humans even in developed parts of the world. The micronutrient has several established functions in the brain; however, the consequences of its deficiency are not well characterised. To elucidate the effects of VitC deficiency on the brain, increased knowledge about the distribution of VitC to the brain and within different brain regions after varying dietary concentrations is needed. In the present study, guinea pigs (like humans lacking the ability to synthesise VitC) were randomly divided into six groups (n 10) that received different concentrations of VitC ranging from 100 to 1500 mg/kg feed for 8 weeks, after which VitC concentrations in biological fluids and tissues were measured using HPLC. The distribution of VitC was found to be dynamic and dependent on dietary availability. Brain saturation was region specific, occurred at low dietary doses, and the dose-concentration relationship could be approximated with a three-parameter Hill equation. The correlation between plasma and brain concentrations of VitC was moderate compared with other organs, and during non-scorbutic VitC deficiency, the brain was able to maintain concentrations from about one-quarter to half of sufficient levels depending on the region, whereas concentrations in other tissues decreased to one-sixth or less. The adrenal glands have similar characteristics to the brain. The observed distribution kinetics with a low dietary dose needed for saturation and exceptional retention ability suggest that the brain and adrenal glands are high priority tissues with regard to the distribution of VitC.
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Senthilkumari S, Talwar B, Dharmalingam K, Ravindran RD, Jayanthi R, Sundaresan P, Saravanan C, Young IS, Dangour AD, Fletcher AE. Polymorphisms in sodium-dependent vitamin C transporter genes and plasma, aqueous humor and lens nucleus ascorbate concentrations in an ascorbate depleted setting. Exp Eye Res 2014; 124:24-30. [PMID: 24815519 DOI: 10.1016/j.exer.2014.04.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 04/28/2014] [Indexed: 01/06/2023]
Abstract
We have previously reported low concentrations of plasma ascorbate and low dietary vitamin C intake in the older Indian population and a strong inverse association of these with cataract. Little is known about ascorbate levels in aqueous humor and lens in populations habitually depleted of ascorbate and no studies in any setting have investigated whether genetic polymorphisms influence ascorbate levels in ocular tissues. Our objectives were to investigate relationships between ascorbate concentrations in plasma, aqueous humor and lens and whether these relationships are influenced by Single Nucleotide Polymorphisms (SNPs) in sodium-dependent vitamin C transporter genes (SLC23A1 and SLC23A2). We enrolled sixty patients (equal numbers of men and women, mean age 63 years) undergoing small incision cataract surgery in southern India. We measured ascorbate concentrations in plasma, aqueous humor and lens nucleus using high performance liquid chromatography. SLC23A1 SNPs (rs4257763, rs6596473) and SLC23A2 SNPs (rs1279683 and rs12479919) were genotyped using a TaqMan assay. Patients were interviewed for lifestyle factors which might influence ascorbate. Plasma vitamin C was normalized by a log10 transformation. Statistical analysis used linear regression with the slope of the within-subject associations estimated using beta (β) coefficients. The ascorbate concentrations (μmol/L) were: plasma ascorbate, median and inter-quartile range (IQR), 15.2 (7.8, 34.5), mean (SD) of aqueous humor ascorbate, 1074 (545) and lens nucleus ascorbate, 0.42 (0.16) (μmol/g lens nucleus wet weight). Minimum allele frequencies were: rs1279683 (0.28), rs12479919 (0.30), rs659647 (0.48). Decreasing concentrations of ocular ascorbate from the common to the rare genotype were observed for rs6596473 and rs12479919. The per allele difference in aqueous humor ascorbate for rs6596473 was -217 μmol/L, p < 0.04 and a per allele difference in lens nucleus ascorbate of -0.085 μmol/g, p < 0.02 for rs12479919. The β coefficients for the regression of log10 plasma ascorbate on aqueous humor ascorbate were higher for the GG genotype of rs6596473: GG, β = 1460 compared to carriage of the C allele, CG, β = 1059, CC, β = 1132, p interaction = 0.1. In conclusion we found that compared to studies in well-nourished populations, ascorbate concentrations in the plasma, aqueous humor and lens nucleus were low. We present novel findings that polymorphisms in SLC23A1/2 genes influenced ascorbate concentration in aqueous humor and lens nucleus.
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Affiliation(s)
- Srinivasan Senthilkumari
- Department of Ocular Pharmacology, Aravind Medical Research Foundation, Madurai, Tamilnadu, India
| | - Badri Talwar
- Aravind Eye Hospital Pondicherry, Aravind Eye Care, Pondicherry, India
| | | | | | | | - Periasamy Sundaresan
- Department of Genetics, Aravind Medical Research Foundation, Madurai, Tamilnadu, India
| | - Charu Saravanan
- Department of Genetics, Aravind Medical Research Foundation, Madurai, Tamilnadu, India
| | - Ian S Young
- Centre for Public Health, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, United Kingdom
| | - Alan D Dangour
- Faculty of Epidemiology & Population Health, London School of Hygiene & Tropical Medicine, Keppel St, London WC1E 7HT, United Kingdom
| | - Astrid E Fletcher
- Faculty of Epidemiology & Population Health, London School of Hygiene & Tropical Medicine, Keppel St, London WC1E 7HT, United Kingdom.
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Muñoz-Montesino C, Roa FJ, Peña E, González M, Sotomayor K, Inostroza E, Muñoz CA, González I, Maldonado M, Soliz C, Reyes AM, Vera JC, Rivas CI. Mitochondrial ascorbic acid transport is mediated by a low-affinity form of the sodium-coupled ascorbic acid transporter-2. Free Radic Biol Med 2014; 70:241-54. [PMID: 24594434 DOI: 10.1016/j.freeradbiomed.2014.02.021] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 02/17/2014] [Accepted: 02/24/2014] [Indexed: 10/25/2022]
Abstract
Despite the fundamental importance of the redox metabolism of mitochondria under normal and pathological conditions, our knowledge regarding the transport of vitamin C across mitochondrial membranes remains far from complete. We report here that human HEK-293 cells express a mitochondrial low-affinity ascorbic acid transporter that molecularly corresponds to SVCT2, a member of the sodium-coupled ascorbic acid transporter family 2. The transporter SVCT1 is absent from HEK-293 cells. Confocal colocalization experiments with anti-SVCT2 and anti-organelle protein markers revealed that most of the SVCT2 immunoreactivity was associated with mitochondria, with minor colocalization at the endoplasmic reticulum and very low immunoreactivity at the plasma membrane. Immunoblotting of proteins extracted from highly purified mitochondrial fractions confirmed that SVCT2 protein was associated with mitochondria, and transport analysis revealed a sigmoidal ascorbic acid concentration curve with an apparent ascorbic acid transport Km of 0.6mM. Use of SVCT2 siRNA for silencing SVCT2 expression produced a major decrease in mitochondrial SVCT2 immunoreactivity, and immunoblotting revealed decreased SVCT2 protein expression by approximately 75%. Most importantly, the decreased protein expression was accompanied by a concomitant decrease in the mitochondrial ascorbic acid transport rate. Further studies using HEK-293 cells overexpressing SVCT2 at the plasma membrane revealed that the altered kinetic properties of mitochondrial SVCT2 are due to the ionic intracellular microenvironment (low in sodium and high in potassium), with potassium acting as a concentration-dependent inhibitor of SVCT2. We discarded the participation of two glucose transporters previously described as mitochondrial dehydroascorbic acid transporters; GLUT1 is absent from mitochondria and GLUT10 is not expressed in HEK-293 cells. Overall, our data indicate that intracellular SVCT2 is localized in mitochondria, is sensitive to an intracellular microenvironment low in sodium and high in potassium, and functions as a low-affinity ascorbic acid transporter. We propose that the mitochondrial localization of SVCT2 is a property shared across cells, tissues, and species.
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Affiliation(s)
- Carola Muñoz-Montesino
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Francisco J Roa
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Eduardo Peña
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Mauricio González
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Kirsty Sotomayor
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Eveling Inostroza
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Carolina A Muñoz
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Iván González
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Mafalda Maldonado
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Carlos Soliz
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Alejandro M Reyes
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Campus Isla Teja, Valdivia, Chile
| | - Juan Carlos Vera
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Coralia I Rivas
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile.
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17
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Amir Shaghaghi M, Bernstein CN, Serrano León A, El-Gabalawy H, Eck P. Polymorphisms in the sodium-dependent ascorbate transporter gene SLC23A1 are associated with susceptibility to Crohn disease. Am J Clin Nutr 2014; 99:378-83. [PMID: 24284447 DOI: 10.3945/ajcn.113.068015] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Crohn disease (CD) and ulcerative colitis (UC) are 2 common inflammatory bowel diseases (IBDs) associated with intestinal inflammation and tissue damage. Oxidative stress is suggested to play a major role in the initiation and progression of IBD. Vitamin C (ascorbate, ascorbic acid) supplementation has reduced oxidative stress in persons with IBD. The role of ascorbate transporters in IBD remains to be determined. SLC23A1 is a major ascorbate transporter in the intestinal tract, and some of its genetic variants have been associated with severely decreased ascorbate transport and lower systemic concentrations. OBJECTIVE This study aimed to determine whether common genetic variants in the vitamin C transporter SLC23A1 are associated with the risk of IBD. DESIGN Genomic DNA samples from patients with CD (n = 162) and UC (n = 149) from the Manitoba IBD Cohort Study and ethnically matched controls (n = 142) were genotyped for 3 SLC23A1 polymorphisms (rs6596473, rs33972313, and rs10063949) by using TaqMan assays. RESULTS Variation at rs10063949 (G allele for heterozygote and homozygote) was associated with increased susceptibility to CD (OR: 2.54; 95% CI: 1.38, 4.66; OR: 4.72; 95% CI: 2.53, 8.81; P < 0.0001; respectively). A strong linkage disequilibrium (LD) was observed across the SLC23A1 region (variation rs6596473 with rs10063949) for CD and UC (D' = 0.94 and 0.96, respectively). The risk alleles confirmed a haplotype (CGG) that is carried more in CD patients (65.3%, P < 0.0001) than in controls (43.5%). CONCLUSIONS A genetic variant (rs10063949-G) in the SLC23A1 ascorbate transporter locus was identified and is associated with an increased risk of CD in a white Canadian IBD cohort. The presented evidence that SLC23A1 variations can modulate the risk of CD has implications for understanding ascorbate transport in CD patients and provides a novel opportunity toward individualized nutritional therapy for patients carrying the disease-associated genotype.
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Affiliation(s)
- Mandana Amir Shaghaghi
- From Human Nutritional Sciences (MAS, ASL, and PE), The Richardson Centre for Functional Foods and Nutraceuticals (MAS, ASL, and PE), the IBD Clinical and Research Centre (CNB), and the Department of Internal Medicine (CNB and HE-G), University of Manitoba, Winnipeg, Canada
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Minegaki T, Kuwahara A, Yamamori M, Nakamura T, Okuno T, Miki I, Omatsu H, Tamura T, Hirai M, Azuma T, Sakaeda T, Nishiguchi K. Genetic polymorphisms in SLC23A2 as predictive biomarkers of severe acute toxicities after treatment with a definitive 5-fluorouracil/cisplatin-based chemoradiotherapy in Japanese patients with esophageal squamous cell carcinoma. Int J Med Sci 2014; 11:321-6. [PMID: 24578608 PMCID: PMC3936025 DOI: 10.7150/ijms.7654] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 01/22/2014] [Indexed: 01/18/2023] Open
Abstract
OBJECTIVE Definitive chemoradiotherapy (CRT) with 5-fluorouracil (5-FU) and cisplatin (CDDP) is one of the standard therapies for esophageal squamous cell carcinoma (ESCC); however, inter-individual variations in clinical outcomes have yet to be investigated. In the present study, single nucleotide polymorphisms (SNPs) in SLC23A2 gene were retrospectively evaluated in 49 Japanese patients with ESCC who were treated with a definitive 5-FU/CDDP-based CRT, and the predictive values for the clinical response, severe acute toxicities, and long-term survival were assessed. METHODS A course consisted of the continuous infusion of 5-FU at 400 mg/m(2)/day for days 1-5 and 8-12, the infusion of CDDP at 40 mg/m(2)/day on days 1 and 8, and radiation at 2 Gy/day on days 1 to 5, 8 to 12, and 15 to 19, with a second course being repeated after a 2-week interval. The SLC23A2 SNPs rs2681116, rs13037458, rs1715364, rs4987219, and rs1110277 were evaluated. RESULTS The rs2681116 and rs13037458 had a tendency to predict the clinical response (p=0.144 and 0.085, respectively) and long-term survival (p=0.142 and 0.056, respectively). The rs4987219 and rs1110277 correlated with severe acute leukopenia (p=0.025) and stomatitis (p=0.019), respectively. CONCLUSIONS Further investigations with a larger number of patients or an in vitro study are needed to confirm the predictive values of genetic polymorphisms in SLC23A2.
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Affiliation(s)
- Tetsuya Minegaki
- 1. Faculty of Pharmaceutical Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan
| | - Akiko Kuwahara
- 2. Kobe University Graduate School of Medicine, Kobe 650-0017, Japan. ; 3. School of Pharmacy and Pharmaceutical Sciences, Mukogawa Women's University, Nishinomiya 663-8179, Japan
| | - Motohiro Yamamori
- 2. Kobe University Graduate School of Medicine, Kobe 650-0017, Japan. ; 3. School of Pharmacy and Pharmaceutical Sciences, Mukogawa Women's University, Nishinomiya 663-8179, Japan
| | - Tsutomu Nakamura
- 2. Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Tatsuya Okuno
- 2. Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Ikuya Miki
- 2. Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Hideaki Omatsu
- 2. Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Takao Tamura
- 2. Kobe University Graduate School of Medicine, Kobe 650-0017, Japan. ; 4. Department of Medical Oncology, Nara Hospital, Kinki University Faculty of Medicine, Nara 630-0293, Japan
| | - Midori Hirai
- 2. Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Takeshi Azuma
- 2. Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Toshiyuki Sakaeda
- 2. Kobe University Graduate School of Medicine, Kobe 650-0017, Japan. ; 5. Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Kohshi Nishiguchi
- 1. Faculty of Pharmaceutical Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan. ; 2. Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
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Variation in the sodium-dependent vitamin C transporter 2 gene is associated with risk of acute coronary syndrome among women. PLoS One 2013; 8:e70421. [PMID: 23990905 PMCID: PMC3749152 DOI: 10.1371/journal.pone.0070421] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 06/18/2013] [Indexed: 01/07/2023] Open
Abstract
Background Vitamin C is associated with a lower risk of coronary heart disease possibly due to its anti-oxidative effects, beneficial effects on endothelial function and importance in collagen synthesis. The sodium-dependent vitamin C transporter 2 is responsible for the transport of vitamin C into various cells and malfunction of this protein leads to reduced vitamin C in tissue, including the arterial wall. We tested the hypothesis that candidate variations rs6139591 and rs1776964 in the gene coding for sodium-dependent vitamin C transporter 2 are associated with development of acute coronary syndrome. Design In the Danish Diet, Cancer and Health cohort study, we performed a case-cohort study among 57,053 subjects aged 50–64 years. Results During a mean follow-up period of 6.4 years, we identified 936 cases and randomly selected a sub-cohort (n = 1,580) with full information on genotypes and covariates. Using Cox proportional hazard models, we found that women with the rs6139591 TT genotype and a lower than median dietary vitamin C intake had a higher risk of acute coronary syndrome compared with those with the CC genotype (adjusted HR 5.39, 95% confidence interval, 2.01–14.50). We also observed a not as strong but positive although inconsistent association for women at a higher than median intake of vitamin C rich food. For the rs1776964 polymorphism, we found a higher risk (adjusted HR 3.45, 95% CI, 1.16–10.28) among TT-homozygous women with higher than median vitamin C intake compared with the CC genotype and low vitamin C intake. Among men, weaker and non-significant associations were observed for both polymorphisms. Conclusion Genetic variation in the sodium-dependent vitamin C transporter 2 is associated with risk of incident acute coronary syndrome in women. The genotype effects may not be fully compensated by a higher intake of vitamin C rich food.
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Lindblad M, Tveden-Nyborg P, Lykkesfeldt J. Regulation of vitamin C homeostasis during deficiency. Nutrients 2013; 5:2860-79. [PMID: 23892714 PMCID: PMC3775232 DOI: 10.3390/nu5082860] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 07/15/2013] [Accepted: 07/18/2013] [Indexed: 12/31/2022] Open
Abstract
Large cross-sectional population studies confirm that vitamin C deficiency is common in humans, affecting 5%–10% of adults in the industrialized world. Moreover, significant associations between poor vitamin C status and increased morbidity and mortality have consistently been observed. However, the absorption, distribution and elimination kinetics of vitamin C in vivo are highly complex, due to dose-dependent non-linearity, and the specific regulatory mechanisms are not fully understood. Particularly, little is known about how adaptive mechanisms during states of deficiency affect the overall regulation of vitamin C transport in the body. This review discusses mechanisms of vitamin C transport and potential means of regulation with special emphasis on capacity and functional properties, such as differences in the Km of vitamin C transporters in different target tissues, in some instances demonstrating a tissue-specific distribution.
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Affiliation(s)
- Maiken Lindblad
- Section of Experimental Animal Models, Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Ridebanevej 9, Frederiksberg C 1870, Denmark.
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Duell EJ, Lujan-Barroso L, Llivina C, Muñoz X, Jenab M, Boutron-Ruault MC, Clavel-Chapelon F, Racine A, Boeing H, Buijsse B, Canzian F, Johnson T, Dalgård C, Overvad K, Tjønneland A, Olsen A, Sánchez SC, Sánchez-Cantalejo E, Huerta JM, Ardanaz E, Dorronsoro M, Khaw KT, Travis RC, Trichopoulou A, Trichopoulos D, Rafnsson S, Palli D, Sacerdote C, Tumino R, Panico S, Grioni S, Bueno-de-Mesquita HB, Ros MM, Numans ME, Peeters PH, Johansen D, Lindkvist B, Johansson M, Johansson I, Skeie G, Weiderpass E, Duarte-Salles T, Stenling R, Riboli E, Sala N, González CA. Vitamin C transporter gene (SLC23A1 and SLC23A2) polymorphisms, plasma vitamin C levels, and gastric cancer risk in the EPIC cohort. GENES AND NUTRITION 2013; 8:549-60. [PMID: 23737080 DOI: 10.1007/s12263-013-0346-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Accepted: 05/07/2013] [Indexed: 01/12/2023]
Abstract
Vitamin C is known to protect mucosal tissues from oxidative stress and inhibit nitrosamine formation in the stomach. High consumption of fruits, particularly citrus, and higher circulating vitamin C concentrations may be inversely associated with gastric cancer (GC) risk. We investigated 20 polymorphisms in vitamin C transporter genes SCL23A1 and SCL23A2 and GC risk in 365 cases and 1,284 controls nested within the European Prospective Investigation into Cancer and Nutrition cohort. We also evaluated the association between these polymorphisms and baseline plasma vitamin C levels in a subset of participants. Four SNPs were predictors of plasma vitamin C levels (SLC23A1 rs11950646 and rs33972313; SLC23A2 rs6053005 and rs6133175) in multivariable linear regression models. One SNP (SLC23A2 rs6116569) was associated with GC risk, in particular non-cardia GC (OR = 1.63, 95 % CI = 1.11-2.39, based on 178 non-cardia cases), but this association was attenuated when plasma vitamin C was included in the logistic regression model. Haplotype analysis of SLC23A1 yielded no associations with GC. In SLC23A2, one haplotype was associated with both overall and non-cardia GC, another haplotype was associated with GC overall, and a third was associated with intestinal-type GC. Common variants in SLC23A1 and SLC23A2 may influence plasma vitamin C concentration independent of dietary intake, and variation in SLC23A2 may influence GC risk. Additional prospective studies in large populations and consortia are recommended. Investigation of variation in vitamin C transporter genes may shed light on the preventative properties of vitamin C in gastric carcinogenesis.
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Affiliation(s)
- Eric J Duell
- Unit of Nutrition, Environment and Cancer, Cancer Epidemiology Research Program, alan Institute of Oncology (ICO), Avda Gran Via 199-203, 08908 L'Hospitalet de Llobregat, Barcelona, Spain,
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Michels AJ, Hagen TM, Frei B. Human genetic variation influences vitamin C homeostasis by altering vitamin C transport and antioxidant enzyme function. Annu Rev Nutr 2013; 33:45-70. [PMID: 23642198 DOI: 10.1146/annurev-nutr-071812-161246] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
New evidence for the regulation of vitamin C homeostasis has emerged from several studies of human genetic variation. Polymorphisms in the genes encoding sodium-dependent vitamin C transport proteins are strongly associated with plasma ascorbate levels and likely impact tissue cellular vitamin C status. Furthermore, genetic variants of proteins that suppress oxidative stress or detoxify oxidatively damaged biomolecules, i.e., haptoglobin, glutathione-S-transferases, and possibly manganese superoxide dismutase, affect ascorbate levels in the human body. There also is limited evidence for a role of glucose transport proteins. In this review, we examine the extent of the variation in these genes, their impact on vitamin C status, and their potential role in altering chronic disease risk. We conclude that future epidemiological studies should take into account genetic variation in order to successfully determine the role of vitamin C nutriture or supplementation in human vitamin C status and chronic disease risk.
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Kuzmanova D, Jansen IDC, Schoenmaker T, Nazmi K, Teeuw WJ, Bizzarro S, Loos BG, van der Velden U. Vitamin C in plasma and leucocytes in relation to periodontitis. J Clin Periodontol 2012; 39:905-12. [DOI: 10.1111/j.1600-051x.2012.01927.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/19/2012] [Indexed: 12/13/2022]
Affiliation(s)
- Denica Kuzmanova
- Department of Periodontology and Oral Biochemistry; Academic Centre for Dentistry Amsterdam (ACTA); University of Amsterdam and VU University Amsterdam; The Netherlands
| | - Ineke D. C. Jansen
- Department of Periodontology and Oral Biochemistry; Academic Centre for Dentistry Amsterdam (ACTA); University of Amsterdam and VU University Amsterdam; The Netherlands
| | - Ton Schoenmaker
- Department of Periodontology and Oral Biochemistry; Academic Centre for Dentistry Amsterdam (ACTA); University of Amsterdam and VU University Amsterdam; The Netherlands
| | - Kamran Nazmi
- Department of Periodontology and Oral Biochemistry; Academic Centre for Dentistry Amsterdam (ACTA); University of Amsterdam and VU University Amsterdam; The Netherlands
| | - Wijnand J. Teeuw
- Department of Periodontology and Oral Biochemistry; Academic Centre for Dentistry Amsterdam (ACTA); University of Amsterdam and VU University Amsterdam; The Netherlands
| | - Sergio Bizzarro
- Department of Periodontology and Oral Biochemistry; Academic Centre for Dentistry Amsterdam (ACTA); University of Amsterdam and VU University Amsterdam; The Netherlands
| | - Bruno G. Loos
- Department of Periodontology and Oral Biochemistry; Academic Centre for Dentistry Amsterdam (ACTA); University of Amsterdam and VU University Amsterdam; The Netherlands
| | - Ubele van der Velden
- Department of Periodontology and Oral Biochemistry; Academic Centre for Dentistry Amsterdam (ACTA); University of Amsterdam and VU University Amsterdam; The Netherlands
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25
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May JM. The SLC23 family of ascorbate transporters: ensuring that you get and keep your daily dose of vitamin C. Br J Pharmacol 2012; 164:1793-801. [PMID: 21418192 DOI: 10.1111/j.1476-5381.2011.01350.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The ascorbate transporters SVCT1 and SVCT2 are crucial for maintaining intracellular ascorbate concentrations in most cell types. Although the two transporter isoforms are highly homologous, they have different physiologic functions. The SVCT1 is located primarily in epithelial cells and has its greatest effect in reabsorbing ascorbate in the renal tubules. The SVCT2 is located in most non-epithelial tissues, with the highest expression in brain and neuroendocrine tissues. These transporters are hydrophobic membrane proteins that have a high affinity and are highly selective for ascorbate. Their ability to concentrate ascorbate inside cells is driven by the sodium gradient across the plasma membrane as generated by Na+/K+ ATPase. They can concentrate ascorbate 20 to 60-fold over plasma ascorbate concentrations. Ascorbate transport on these proteins is regulated at the transcriptional, translational and post-translational levels. Available studies show that transporter function is acutely regulated by protein kinases A and C, whereas transporter expression is increased by low intracellular ascorbate and associated oxidative stress. The knockout of the SVCT2 in mice is lethal on day 1 of life, and almost half of SVCT1 knockout mice do not survive to weaning. These findings confirm the importance both of cellular ascorbate and of the two transport proteins as key to maintaining intracellular ascorbate. LINKED ARTICLES This article is part of a themed section on Transporters. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2011.164.issue-7.
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Affiliation(s)
- James M May
- Departments of Medicine and Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232-0475, USA.
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26
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Eck P, Erichsen HC, Taylor JG, Corpe C, Chanock SJ, Levine M. Genomic and functional analysis of the sodium-dependent vitamin C transporter SLC23A1-SVCT1. GENES AND NUTRITION 2011; 2:143-5. [PMID: 18850166 DOI: 10.1007/s12263-007-0040-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Peter Eck
- Molecular and Clinical Nutrition Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA,
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Belin S, Kaya F, Burtey S, Fontes M. Ascorbic Acid and gene expression: another example of regulation of gene expression by small molecules? Curr Genomics 2011; 11:52-7. [PMID: 20808524 PMCID: PMC2851117 DOI: 10.2174/138920210790217936] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Revised: 09/24/2009] [Accepted: 10/22/2009] [Indexed: 01/31/2023] Open
Abstract
Ascorbic acid (vitamin C, AA) has long been considered a food supplement necessary for life and for preventing scurvy. However, it has been reported that other small molecules such as retinoic acid (vitamin A) and different forms of calciferol (vitamin D) are directly involved in regulating the expression of numerous genes. These molecules bind to receptors that are differentially expressed in the embryo and are therefore crucial signalling molecules in vertebrate development. The question is: is ascorbic acid also a signalling molecule that regulates gene expression? We therefore present and discuss recent publications that demonstrate that AA regulates the expression of a battery of genes. We offer a clue to understanding the biochemical mechanism by which AA regulates gene expression. Finally we will discuss the question of a receptor for AA and its potential involvement in embryonic development and cell differentiation.
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Affiliation(s)
- Sophie Belin
- Therapy of Genetic Disorders, EA 4263, Faculté de Médecine de la Timone, Université de la Méditerranée, Marseille, France
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28
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Hepatic expression of sodium-dependent vitamin C transporters: ontogeny, subtissular distribution and effect of chronic liver diseases. Br J Nutr 2011; 106:1814-25. [DOI: 10.1017/s0007114511002273] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Ascorbic acid uptake is a key step in determining the overall bioactivity of this vitamin. Expression of Na-dependent vitamin C transporters (SVCT; SLC23A1 and SLC23A2) during long-term oxidative stress occurring in several chronic liver diseases may determine the antioxidant defence in this organ. In patients with hepatocellular cholestasis, primary biliary cirrhosis, haemochromatosis and non-alcoholic steatohepatitis, using real-time RT-PCR, an enhanced hepatic expression of both SLC23A1 and SLC23A2, but not other organic anions transporters, such as OATP1A2, OATP1B1 and OATP1B3, was found. To further investigate these findings, we used secondary biliary cirrhosis induced in rats by long-term biliary obstruction as a model of chronic liver disease accompanied by oxidative stress because of bile acid accumulation. In control rat liver, expression of Slc23a1 was low at birth, increased progressively up to adulthood and decreased in senescence, whereas expression of Slc23a2 did not change significantly after birth. In 8-week-old rats, immunohistochemistry and confocal microscopy studies revealed the expression in hepatocytes and bile duct cells of mainly Slc23a1, whereas both Slc23a1 and Slc23a2 were expressed in endothelial, stellate and Kupffer cells. In adult rats, when obstructive cholestasis was maintained for 8 weeks, a significant up-regulation of Slc23a2 accompanied by a down-regulation of Slc23a1 was found. In sum, there is a selective cell-type distribution of SVCT in the liver tissue, which, in addition to differential control in the expression of both isoforms, may play a role in the ability of different liver cell types to take up vitamin C under physiological and pathological conditions.
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May JM. The SLC23 family of ascorbate transporters: ensuring that you get and keep your daily dose of vitamin C. Br J Pharmacol 2011. [PMID: 21418192 DOI: 10.1111/bph.2011.164.issue-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The ascorbate transporters SVCT1 and SVCT2 are crucial for maintaining intracellular ascorbate concentrations in most cell types. Although the two transporter isoforms are highly homologous, they have different physiologic functions. The SVCT1 is located primarily in epithelial cells and has its greatest effect in reabsorbing ascorbate in the renal tubules. The SVCT2 is located in most non-epithelial tissues, with the highest expression in brain and neuroendocrine tissues. These transporters are hydrophobic membrane proteins that have a high affinity and are highly selective for ascorbate. Their ability to concentrate ascorbate inside cells is driven by the sodium gradient across the plasma membrane as generated by Na+/K+ ATPase. They can concentrate ascorbate 20 to 60-fold over plasma ascorbate concentrations. Ascorbate transport on these proteins is regulated at the transcriptional, translational and post-translational levels. Available studies show that transporter function is acutely regulated by protein kinases A and C, whereas transporter expression is increased by low intracellular ascorbate and associated oxidative stress. The knockout of the SVCT2 in mice is lethal on day 1 of life, and almost half of SVCT1 knockout mice do not survive to weaning. These findings confirm the importance both of cellular ascorbate and of the two transport proteins as key to maintaining intracellular ascorbate. LINKED ARTICLES This article is part of a themed section on Transporters. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2011.164.issue-7.
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Affiliation(s)
- James M May
- Departments of Medicine and Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232-0475, USA.
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30
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Timpson NJ, Forouhi NG, Brion MJ, Harbord RM, Cook DG, Johnson P, McConnachie A, Morris RW, Rodriguez S, Luan J, Ebrahim S, Padmanabhan S, Watt G, Bruckdorfer KR, Wareham NJ, Whincup PH, Chanock S, Sattar N, Lawlor DA, Davey Smith G. Genetic variation at the SLC23A1 locus is associated with circulating concentrations of L-ascorbic acid (vitamin C): evidence from 5 independent studies with >15,000 participants. Am J Clin Nutr 2010; 92:375-82. [PMID: 20519558 PMCID: PMC3605792 DOI: 10.3945/ajcn.2010.29438] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND L-ascorbic acid is an essential part of the human diet and has been associated with a wide range of chronic complex diseases, including cardiovascular outcomes. To date, there are no confirmed genetic correlates of circulating concentrations of L-ascorbic acid. OBJECTIVE We aimed to confirm the existence of an association between common variation at the SLC23A1 gene locus and circulating concentrations of L-ascorbic acid. DESIGN We used a 2-stage design, which included a discovery cohort (the British Women's Heart and Health Study), a series of follow-up cohorts, and meta-analysis (totaling 15,087 participants) to assess the relation between variation at SLC23A1 and circulating concentrations of L-ascorbic acid. RESULTS In the discovery cohort, variation at rs33972313 was associated with a reduction in circulating concentrations of L-ascorbic acid (-4.15 micromol/L; 95% CI: -0.49, -7.81 micromol/L; P = 0.03 reduction per minor allele). Pooled analysis of the relation between rs33972313 and circulating L-ascorbic acid across all studies confirmed this and showed that each additional rare allele was associated with a reduction in circulating concentrations of L-ascorbic acid of -5.98 micromol/L (95% CI: -8.23, -3.73 micromol/L; P = 2.0 x 10(-7) per minor allele). CONCLUSIONS A genetic variant (rs33972313) in the SLC23A1 vitamin C active transporter locus was identified that is reliably associated with circulating concentrations of L-ascorbic acid in the general population. This finding has implications more generally for the epidemiologic investigation of relations between circulating L-ascorbic acid and health outcomes.
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Affiliation(s)
- Nicholas J Timpson
- Medical Research Council Centre for Causal Analyses in Translational Epidemiology, University of Bristol, Department of Social Medicine, Oakfield House, Oakfield Grove, Bristol, BS8 2BN, United Kingdom.
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31
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Corpe CP, Tu H, Eck P, Wang J, Faulhaber-Walter R, Schnermann J, Margolis S, Padayatty S, Sun H, Wang Y, Nussbaum RL, Espey MG, Levine M. Vitamin C transporter Slc23a1 links renal reabsorption, vitamin C tissue accumulation, and perinatal survival in mice. J Clin Invest 2010; 120:1069-83. [PMID: 20200446 DOI: 10.1172/jci39191] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Accepted: 01/06/2010] [Indexed: 01/20/2023] Open
Abstract
Levels of the necessary nutrient vitamin C (ascorbate) are tightly regulated by intestinal absorption, tissue accumulation, and renal reabsorption and excretion. Ascorbate levels are controlled in part by regulation of transport through at least 2 sodium-dependent transporters: Slc23a1 and Slc23a2 (also known as Svct1 and Svct2, respectively). Previous work indicates that Slc23a2 is essential for viability in mice, but the roles of Slc23a1 for viability and in adult physiology have not been determined. To investigate the contributions of Slc23a1 to plasma and tissue ascorbate concentrations in vivo, we generated Slc23a1-/- mice. Compared with wild-type mice, Slc23a1-/- mice increased ascorbate fractional excretion up to 18-fold. Hepatic portal ascorbate accumulation was nearly abolished, whereas intestinal absorption was marginally affected. Both heterozygous and knockout pups born to Slc23a1-/- dams exhibited approximately 45% perinatal mortality, and this was associated with lower plasma ascorbate concentrations in dams and pups. Perinatal mortality of Slc23a1-/- pups born to Slc23a1-/- dams was prevented by ascorbate supplementation during pregnancy. Taken together, these data indicate that ascorbate provided by the dam influenced perinatal survival. Although Slc23a1-/- mice lost as much as 70% of their ascorbate body stores in urine daily, we observed an unanticipated compensatory increase in ascorbate synthesis. These findings indicate a key role for Slc23a1 in renal ascorbate absorption and perinatal survival and reveal regulation of vitamin C biosynthesis in mice.
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Affiliation(s)
- Christopher P Corpe
- Molecular and Clinical Nutrition Section, Digestive Diseases Branch, Intramural Research Program, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), NIH, Bethesda, Maryland, USA
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32
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Michels AJ, Hagen TM. Hepatocyte nuclear factor 1 is essential for transcription of sodium-dependent vitamin C transporter protein 1. Am J Physiol Cell Physiol 2009; 297:C1220-7. [PMID: 19741195 DOI: 10.1152/ajpcell.00348.2009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Transport and distribution of vitamin C is primarily regulated by the function of sodium-dependent vitamin C transporters (SVCTs). SVCT1 is expressed in the small intestine, liver, and kidney, organs that play a vital role in whole body vitamin C homeostasis. Despite the importance of this protein, little is known about regulation of the gene encoding SVCT1, Slc23a1. In this study, we present the first investigation of the transcriptional regulation of human Slc23a1, identifying transcription factors that may influence its expression. A 1,239-bp genomic DNA fragment corresponding to the 5'-flanking region of Slc23a1 was isolated from a human hepatocarcinoma cell line (HepG2) and sequenced. When cloned into a reporter gene construct, robust transcriptional activity was seen in this sequence, nearly 25-fold above the control vector. Deletion analysis of the SVCT1 reporter gene vector defined the minimal active promoter as a small 135-bp region upstream of the transcriptional start site. While several transcription factor binding sites were identified within this sequence, reporter constructs showed that basal transcription required the binding of hepatic nuclear factor 1 (HNF-1) to its cognate sequence. Furthermore, mutation of this HNF-1 binding site resulted in complete loss of luciferase expression, even in the context of the whole promoter. Additionally, small interfering RNA knockdown of both members of the HNF-1 family, HNF-1alpha and HNF-1beta, resulted in a significant decline in SVCT1 transcription. Together, these data suggest that HNF-1alpha and/or HNF-1beta binding is required for SVCT1 expression and may be involved in the coordinate regulation of whole body vitamin C status.
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Affiliation(s)
- Alexander J Michels
- Linus Pauling Institute and the Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331, USA
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33
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Genetic variation in sodium-dependent ascorbic acid transporters and risk of gastric cancer in Poland. Eur J Cancer 2009; 45:1824-30. [PMID: 19243932 DOI: 10.1016/j.ejca.2009.01.027] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Revised: 01/15/2009] [Accepted: 01/22/2009] [Indexed: 02/06/2023]
Abstract
Higher ascorbic acid consumption is associated with a reduced risk of gastric cancer in numerous epidemiologic studies. We investigated whether single nucleotide polymorphisms (SNPs) in SLC23A1 and SLC23A2--genes that encode key ascorbic acid transport proteins--affect gastric cancer risk in 279 incident cases and 414 age- and gender-matched controls drawn from a population-based case-control study in Poland. Compared to subjects who were homozygous for the common G allele of the SLC23A2 SNP rs12479919, carriers of the AA genotype had a 41% lower risk of gastric cancer [odds ratio (OR)=0.59, 95% confidence interval (CI): 0.36-0.95; P trend=0.06]. A haplotype that contained the common allele of the rs6139591, rs2681116 and rs14147458 SNPs in SLC23A2 was also significantly inversely associated with gastric malignancy. No other polymorphisms in either gene were related to risk, and there was no effect modification by ascorbic acid intake. These findings suggest that genetic variation in SLC23A2 impacts gastric cancer risk, although confirmation in other studies is required.
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34
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Nakamura YK, Flintoff-Dye N, Omaye ST. Conjugated linoleic acid modulation of risk factors associated with atherosclerosis. Nutr Metab (Lond) 2008. [PMID: 18718021 DOI: 10.1186/1743-7075.5-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Conjugated linoleic acid (CLA) has been the subject of extensive investigation regarding its possible benefits on a variety of human diseases. In some animal studies, CLA has been shown to have a beneficial effect on sclerotic lesions associated with atherosclerosis, be a possible anti-carcinogen, increase feed efficiency, and act as a lean body mass supplement. However, the results have been inconsistent, and the effects of CLA on atherogenesis appear to be dose-, isomer-, tissue-, and species-specific. Similarly, CLA trials in humans have resulted in conflicting findings. Both the human and animal study results may be attributed to contrasting doses of CLA, isomers, the coexistence of other dietary fatty acids, length of study, and inter-and/or intra-species diversities. Recent research advances have suggested the importance of CLA isomers in modulating gene expression involved in oxidative damage, fatty acid metabolism, immune/inflammatory responses, and ultimately atherosclerosis. Although the possible mechanisms of action of CLA have been suggested, they have yet to be determined.
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Affiliation(s)
- Yukiko K Nakamura
- Environmental Sciences Graduate Program, University of Nevada, Reno 89557, USA.
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35
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Nakamura YK, Flintoff-Dye N, Omaye ST. Conjugated linoleic acid modulation of risk factors associated with atherosclerosis. Nutr Metab (Lond) 2008; 5:22. [PMID: 18718021 PMCID: PMC2546407 DOI: 10.1186/1743-7075-5-22] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2008] [Accepted: 08/21/2008] [Indexed: 01/17/2023] Open
Abstract
Conjugated linoleic acid (CLA) has been the subject of extensive investigation regarding its possible benefits on a variety of human diseases. In some animal studies, CLA has been shown to have a beneficial effect on sclerotic lesions associated with atherosclerosis, be a possible anti-carcinogen, increase feed efficiency, and act as a lean body mass supplement. However, the results have been inconsistent, and the effects of CLA on atherogenesis appear to be dose-, isomer-, tissue-, and species-specific. Similarly, CLA trials in humans have resulted in conflicting findings. Both the human and animal study results may be attributed to contrasting doses of CLA, isomers, the coexistence of other dietary fatty acids, length of study, and inter-and/or intra-species diversities. Recent research advances have suggested the importance of CLA isomers in modulating gene expression involved in oxidative damage, fatty acid metabolism, immune/inflammatory responses, and ultimately atherosclerosis. Although the possible mechanisms of action of CLA have been suggested, they have yet to be determined.
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Affiliation(s)
- Yukiko K Nakamura
- Environmental Sciences Graduate Program, University of Nevada, Reno 89557, USA.
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36
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Erichsen HC, Peters U, Eck P, Welch R, Schoen RE, Yeager M, Levine M, Hayes RB, Chanock S. Genetic variation in sodium-dependent vitamin C transporters SLC23A1 and SLC23A2 and risk of advanced colorectal adenoma. Nutr Cancer 2008; 60:652-9. [PMID: 18791929 PMCID: PMC3490215 DOI: 10.1080/01635580802033110] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Previous observational studies suggest that vitamin C may reduce risk of colorectal cancer. Vitamin C transport is facilitated by membrane bound sodium-dependent transporters, SVCT1 (encoded by SLC23A1) and SVCT2 (encoded by SLC23A2). To investigate if common genetic variants in these two genes are associated with risk of colorectal tumor development, we conducted a case-control study of 656 Caucasian advanced distal colorectal adenoma cases and 665 Caucasian sigmoidoscopy-negative controls nested within the screening arm of the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. The analysis of common single nucleotide polymorphisms in SLC23A1 revealed no association. For SLC23A2, overall, there was no association with haplotypes, but two SNPs located in intron 8 and exon 11 could be associated (odds ratio = 0.49, 95% confidence interval = 0.25-0.95 for haplotype G-C vs. haplotype C-C). The findings should be confirmed in follow-up studies, and further investigation is required to probe the functional basis of this finding.
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Affiliation(s)
- Hans Christian Erichsen
- Section on Genomic Variation, Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892-4605, USA
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37
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Gournas C, Papageorgiou I, Diallinas G. The nucleobase–ascorbate transporter (NAT) family: genomics, evolution, structure–function relationships and physiological role. MOLECULAR BIOSYSTEMS 2008; 4:404-16. [PMID: 18414738 DOI: 10.1039/b719777b] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Christos Gournas
- Faculty of Biology, Department of Botany, University of Athens, Panepistimioupolis, Athens, Greece
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Abstract
Vitamin C is required for collagen synthesis and biosynthesis of certain hormones and recommended dietary intake levels are largely based these requirements. However, to function effectively as an antioxidant (or a pro-oxidant), relatively high levels of this vitamin must be maintained in the body. The instability of vitamin C combined with its relatively poor intestinal absorption and ready excretion from the body reduce physiological availability of this vitamin. This inability to maintain high serum levels of vitamin C may have serious health implications and is particularly relevant in the onset and progression of degenerative disease, such as cancer and cardiovascular disease (CVD), which have a strong contributing oxidative damage factor. In this review, we examine recent studies on the regulation of transport mechanisms for vitamin C, related clinical ramifications, and potential implications in high-dose vitamin C therapy. We also evaluate recent clinical and scientific evidence on the effects of this vitamin on cancer and CVD, with focus on the key mechanisms of action that may contribute to the therapeutic potential of this vitamin in these diseases. Several animal models that could be utilized to address unresolved questions regarding the feasibility of vitamin C therapy are also discussed.
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Affiliation(s)
- Yi Li
- Department of Biology, McMaster University, Hamilton, Ontario, Canada L8S 4K1
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Herbeth B, Guilland JC, Rochette L, Siest G, Visvikis-Siest S. Genetic and environmental contributions to serum ascorbic acid concentrations: the Stanislas Family Study. Br J Nutr 2007; 96:1013-20. [PMID: 17181875 DOI: 10.1017/bjn20061978] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Although numerous environmental factors are documented to influence serum ascorbic concentrations, little is known about the genetic versus environmental contributions to variation of this trait. The aim of this study was to estimate family correlation and, additive genetic heritability and household effects in a variance component analysis for serum ascorbic acid concentrations. In a sample of ninety French families, information was obtained regarding serum ascorbic acid concentrations, usual dietary intake, lifestyle, and other related covariates. Spouse, parent–offspring and offspring–offspring significant correlation coefficients for serum ascorbic acid concentrations, adjusted for age, cigarette consumption and oral contraceptive use, were 0·432, 0·298 and 0·485, respectively, and for adjusted values for additional diet covariates (vitamin C intake and fruit and vegetable consumption), were 0·362, 0·154 and 0·348, respectively. Variance component analysis for serum ascorbic concentrations showed no significant genetic contribution to variability of this trait. Conversely, household common environment accounted for 27·7 and 42·6 % in parents and offspring, respectively, after adjustment for age, cigarette consumption and oral contraceptive use. After adjustment for the two additional diet covariates (vitamin C intake and fruit and vegetable consumption) household common variance decreased to 13·6 and 30·5 % in parents and offspring, respectively. These results show that serum ascorbic acid concentrations aggregate within healthy families partly due to diet intake but without a significant genetic component.
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40
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Somers J, Smith C, Donnison M, Wells DN, Henderson H, McLeay L, Pfeffer PL. Gene expression profiling of individual bovine nuclear transfer blastocysts. Reproduction 2006; 131:1073-84. [PMID: 16735546 DOI: 10.1530/rep.1.00967] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
During somatic cell nuclear transfer the gene expression profile of the donor cell has to be changed or reprogrammed extensively to reflect that of a normal embryo. In this study we focused on the switching on of embryonic genes by screening with a microarray consisting of 5000 independent cDNA isolates derived from a bovine blastocyst library which we constructed for this purpose. Expression profiling was performed using linearly amplified RNA from individual day 7 nuclear transfer (NT) and genetically half-identicalin vitroproduced (IVP) blastocysts. We identified 92 genes expressed at lower levels in NT embryos whereas transcripts of 43 genes were more abundant in NT embryos (P≤ 0.05, ≥ 1.5-fold change). A range of functional categories was represented among the identified genes, with a preponderance of constitutively expressed genes required for the maintenance of basal cellular function. Using a stringent quantitative SYBR-green real time RT-PCR based approach we found, when comparing the means of the expression levels of a larger set of individual embryos, that differences were small (< 2-fold) and only significant for two of the seven analysed genes (KRT18,SLC16A1). Notably, examination of transcript levels of a single gene in individual embryos could not distinguish an NT from a control embryo. This unpredictability of individual gene expression on a global background of multiple gene expression changes argues for a predominantly stochastic nature of reprogramming errors.
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Affiliation(s)
- Joanna Somers
- AgResearch Ruakura, Hamilton, New Zealand and University of Waikato, Department of Biological Sciences, Hamilton
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41
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Erichsen HC, Engel SAM, Eck PK, Welch R, Yeager M, Levine M, Siega-Riz AM, Olshan AF, Chanock SJ. Genetic variation in the sodium-dependent vitamin C transporters, SLC23A1, and SLC23A2 and risk for preterm delivery. Am J Epidemiol 2006; 163:245-54. [PMID: 16357110 DOI: 10.1093/aje/kwj035] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Vitamin C has been the focus of epidemiologic investigation in preterm delivery (<37 weeks' gestation), which is a leading cause of neonatal mortality and birth-related morbidity. There are two sodium-dependent membrane transporters encoded by SLC23A1 and SLC23A2, which have key roles in human vitamin C metabolism and which control dietary uptake, reabsorption, and tissue distribution of vitamin C. Using maternal DNA, the authors evaluated common single-nucleotide polymorphisms (SNPs) in SLC23A1 and SLC23A2 in a nested case-control analysis of the Pregnancy, Infection, and Nutrition Study (1995-2000) cohort. Of the associations observed for both haplotypes in SLC23A1 and individual SNPs in SLC23A2, the most robust finding is with an intron 2 variant in SLC23A2. Heterozygotes and homozygotes for this variant had a 1.7-fold (95% confidence interval: 0.9, 3.3) and a 2.7-fold (95% confidence interval: 1.2, 6.3) elevation in the risk of spontaneous preterm birth, respectively. Semi-Bayesian hierarchical regression analysis, which simultaneously adjusted for multiple SNPs within the same gene, gave comparable results. The authors' findings link genetic variants in the vitamin C transporters to spontaneous preterm birth, which may explain previous dietary associations. If the findings from this study are confirmed, they may serve as the foundation for genetic risk assessment of nutritional pathways in preterm birth.
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Affiliation(s)
- Hans Christian Erichsen
- Section on Genomic Variation, Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
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42
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Davey Smith G, Ebrahim S, Lewis S, Hansell AL, Palmer LJ, Burton PR. Genetic epidemiology and public health: hope, hype, and future prospects. Lancet 2005; 366:1484-98. [PMID: 16243094 DOI: 10.1016/s0140-6736(05)67601-5] [Citation(s) in RCA: 167] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Genetic epidemiology is a rapidly expanding research field, but the implications of findings from such studies for individual or population health are unclear. The use of molecular genetic screening currently has some legitimacy in certain monogenic conditions, but no established value with respect to common complex diseases. Personalised medical care based on molecular genetic testing is also as yet undeveloped for common diseases. Genetic epidemiology can contribute to establishing the causal nature of environmentally modifiable risk factors, through the application of mendelian randomisation approaches and thus contribute to appropriate preventive strategies. Technological and other advances will allow the potential of genetic epidemiology to be revealed over the next few years, and the establishment of large population-based resources for such studies (biobanks) should contribute to this endeavour.
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Affiliation(s)
- George Davey Smith
- Department of Social Medicine, University of Bristol, Canynge Hall, Whiteladies Road, Bristol BS8 2PR, UK.
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43
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Abstract
Ascorbic acid and dehydroascorbic acid (DHAA, oxidized vitamin C) are dietary sources of vitamin C in humans. Both nutrients are absorbed from the lumen of the intestine and renal tubules by, respectively, enterocytes and renal epithelial cells. Subsequently vitamin C circulates in the blood and enters all of the other cells of the body. Concerning flux across the plasma membrane, simple diffusion of ascorbic acid plays only a small or negligible role. More important are specific mechanisms of transport and metabolism that concentrate vitamin C intracellularly to enhance its function as an enzyme cofactor and antioxidant. The known transport mechanisms are facilitated diffusion of DHAA through glucose-sensitive and -insensitive transporters, facilitated diffusion of ascorbate through channels, exocytosis of ascorbate in secretory vesicles, and secondary active transport of ascorbate through the sodium-dependent vitamin C transporters SVCT1 and SVCT2 proteins that are encoded by the genes Slc23a1 and Slc23a2, respectively. Evidence is reviewed indicating that these transport pathways are regulated under physiological conditions and altered by aging and disease.
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Affiliation(s)
- John X Wilson
- Department of Exercise and Nutrition Sciences, School of Public Health and Health Professions, University at Buffalo, Buffalo, New York 14214-3079, USA.
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Jin SN, Mun GH, Lee JH, Oh CS, Kim J, Chung YH, Kang JS, Kim JG, Hwang DH, Hwang YI, Shin DH, Lee WJ. Immunohistochemical study on the distribution of sodium-dependent vitamin C transporters in the respiratory system of adult rat. Microsc Res Tech 2005; 68:360-7. [PMID: 16358281 DOI: 10.1002/jemt.20255] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
As vitamin C (L-ascorbic acid, VC) is known to be essential for many enzymatic reactions, the study on the transport mechanism of VC through cytoplasmic membrane is crucial to understanding physiological role of VC in cells and the respiratory system. In this regard, the study on the newly identified sodium-dependent VC transporters (SVCTs), SVCT1 and SVCT2, is required in organs that contain high concentration of VC. We have shown the distribution of SVCT proteins in the respiratory system, which has been reported to be one of the organs with a high concentration of VC, using immunohistochemical techniques. In the present study, intense SVCT immunoreactivities (IRs) were mainly localized in the respiratory system epithelial cells. In the trachea, both SVCT1 and 2 were localized in the psuedostratified ciliated columnar epithelium. In the terminal bronchiole, SVCT1 and 2 IRs were mainly observed in the apical portion of the simple columnar epithelium. In addition, SVCT IRs was localized within the cell membrane of some alveolar cells, even though we could not identify the exact cell types. These results provide the first evidence that intense SVCT1 and 2 IRs were found in the apical portion of the respiratory epithelial cells, suggesting that SVCT proteins in the apical portion could transport the reduced form of VC included in the airway surface liquid into the respiratory epithelial cells.
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Affiliation(s)
- Shun Nu Jin
- Department of Anatomy, Seoul National University College of Medicine, Seoul, Korea
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