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Farrell CC, Khanna S, Hoque MT, Plaga A, Basset N, Syed I, Biouss G, Aufreiter S, Marcon N, Bendayan R, Kim YI, O'Connor DL. Low-dose daily folic acid (400 μg) supplementation does not affect regulation of folate transporters found present throughout the terminal ileum and colon of humans: a randomized clinical trial. Am J Clin Nutr 2024; 119:809-820. [PMID: 38157986 DOI: 10.1016/j.ajcnut.2023.12.018] [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: 09/05/2023] [Revised: 11/23/2023] [Accepted: 12/26/2023] [Indexed: 01/03/2024] Open
Abstract
BACKGROUND Folic acid supplementation during the periconceptional period reduces the risk of neural tube defects in infants, but concern over chronic folic acid exposure remains. An improved understanding of folate absorption may clarify potential risks. Folate transporters have been characterized in the small intestine, but less so in the colon of healthy, free-living humans. The impact of folic acid fortification or supplementation on regulation of these transporters along the intestinal tract is unknown. OBJECTIVE The objective was to characterize expression of folate transporters/receptor (FT/R) and folate hydrolase, glutamate carboxypeptidase II (GCPII), from the terminal ileum and throughout the colon of adults and assess the impact of supplemental folic acid. METHODS In this 16-wk open-labeled randomized clinical trial, adults consumed a low folic acid-containing diet, a folate-free multivitamin, and either a 400 μg folic acid supplement or no folic acid supplement. Dietary intakes and blood were assessed at baseline, 8 wk, and 16 wk (time of colonoscopy). Messenger RNA (mRNA) expression and protein expression of FT/R and GCPII were assessed in the terminal ileum, cecum, and ascending and descending colon. RESULTS Among 24 randomly assigned subjects, no differences in dietary folate intake or blood folate were observed at baseline. Mean ± SD red blood cell folate at 16 wk was 1765 ± 426 and 911 ± 242 nmol/L in the 400 and 0 μg folic acid group, respectively (P < 0.0001). Reduced folate carrier, proton-coupled folate transporter, and folate-receptor alpha expression were detected in the terminal ileum and colon, as were efflux transporters of breast cancer resistance protein and multidrug resistance protein-3. Other than a higher mRNA expression of FR-alpha and GCPII in the 400 μg supplement group in the ascending colon, no treatment differences were observed (P < 0.02). CONCLUSIONS Folate transporters are present throughout the terminal ileum and colon; there is little evidence that a low dose of folic acid supplementation affects colonic absorption. This trial was registered at clinicaltrials.gov as NCT03421483.
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Affiliation(s)
- Colleen C Farrell
- Department of Nutritional Sciences, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada; Translational Medicine Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Siya Khanna
- Department of Nutritional Sciences, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada; Translational Medicine Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Md Tozammel Hoque
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Aneta Plaga
- Department of Nutritional Sciences, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada; Translational Medicine Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Nancy Basset
- Division of Gastroenterology, Department of Medicine, St. Michael's Hospital, Toronto, Ontario, Canada
| | - Ishba Syed
- Division of Gastroenterology, Department of Medicine, St. Michael's Hospital, Toronto, Ontario, Canada
| | - George Biouss
- Translational Medicine Program, The Hospital for Sick Children, Toronto, Ontario, Canada; Developmental and Stem Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Susanne Aufreiter
- Department of Nutritional Sciences, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada; Translational Medicine Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Norman Marcon
- Division of Gastroenterology, Department of Medicine, St. Michael's Hospital, Toronto, Ontario, Canada
| | - Reina Bendayan
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Young-In Kim
- Division of Gastroenterology, Department of Medicine, St. Michael's Hospital, Toronto, Ontario, Canada; Keenan Research Centre for Biomedical Science of St. Michael's Hospital, Toronto, Ontario, Canada
| | - Deborah L O'Connor
- Department of Nutritional Sciences, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada; Translational Medicine Program, The Hospital for Sick Children, Toronto, Ontario, Canada.
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Bai Y, Wang R, Yang Y, Li R, Wu X. Folic Acid Absorption Characteristics and Effect on Cecal Microbiota of Laying Hens. Front Vet Sci 2021; 8:720851. [PMID: 34485442 PMCID: PMC8416075 DOI: 10.3389/fvets.2021.720851] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Accepted: 07/26/2021] [Indexed: 02/01/2023] Open
Abstract
This experiment was conducted to investigate the characteristics of folic acid (FA) absorption in laying hens and the effect of FA supplementation on cecal microbiota. A total of 432 healthy hens (30-week-old) were randomly assigned to four diets supplemented with FA: 0, 1, 6, and 24 mg/kg of feed for 8 w. Blood, duodenum, jejunum, ileum, cecum, and cecal chyme samples (six samples per treatment) were collected from the hens at the end of the feeding trial. Expression profiles of folate transport and transformation genes in intestine and cecal microbiota were detected. Results showed that serum folate level significantly increased (P < 0.01) with an increase in dietary FA supplementation, reaching a plateau at 6 mg/kg FA supplementation. The expression of FA transport and transformation genes was not affected in the cecum (P > 0.05) by dietary FA supplementation; however, it was affected in the duodenum, jejunum, and ileum and mostly showed a downward trend in treatment groups (P < 0.05). The genes affected include duodenal folate receptor (Folr) and dihydrofolate reductase (Dhfr), jejunal proton-coupled folate transporter (Pcft) and reduced folate carrier (Rfc), and ileal ATP binding cassette subfamily C member (Abcc2), Abcc3, Rfc, Folr, and Dhfr. Furthermore, according to the operational taxonomic unit classification and taxonomic position identification, the cecal microbiota population of the hens was not affected by dietary FA supplementation at the phylum, class, order, family, genus, and species levels (P > 0.05). However, the relative abundance of some microbiota was affected by dietary FA supplementation (P < 0.05). In conclusion, FA transport from the intestinal lumen into enterocytes, and then into the bloodstream, is strictly regulated, which may be associated with the regulation of the expression profiles of genes involved in FA absorption. Pathogenic bacteria decreased in the cecum, especially at 24 mg/kg supplementation, but the beneficial bacteria (Bifidobacteriaceae) decreased at this level, too. Overall, FA supplementation at 6 mg/kg, which was selected for folate-enriched egg production, did not affect the health and metabolism of laying hens negatively.
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Affiliation(s)
- Yan Bai
- Laboratory of Poultry Production, College of Animal Science, Shanxi Agricultural University, Jinzhong, China
| | - Rui Wang
- Laboratory of Poultry Production, College of Animal Science, Shanxi Agricultural University, Jinzhong, China.,Department of Life Sciences, Luliang University, Luliang, China
| | - Yu Yang
- Laboratory of Poultry Production, College of Animal Science, Shanxi Agricultural University, Jinzhong, China
| | - Ruirui Li
- Laboratory of Poultry Production, College of Animal Science, Shanxi Agricultural University, Jinzhong, China
| | - Xiaotian Wu
- Laboratory of Poultry Production, College of Animal Science, Shanxi Agricultural University, Jinzhong, China
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Losada-Medina D, Yitbarek A, Nazeer N, Uribe-Diaz S, Ahmed M, Rodriguez-Lecompte JC. Identification, tissue characterization, and innate immune role of Angiogenin-4 expression in young broiler chickens. Poult Sci 2020; 99:2992-3000. [PMID: 32475434 PMCID: PMC7597696 DOI: 10.1016/j.psj.2020.03.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 01/21/2020] [Accepted: 03/09/2020] [Indexed: 12/29/2022] Open
Abstract
Intestinal epithelial cells are major producers of antimicrobial proteins, which play an important role in innate immunity. In addition to defensins, the Ribonuclease A superfamily includes important antimicrobial proteins involved in host-defense mechanisms in vertebrates. Angiogenin-4 (Ang4), a member of this RNase superfamily, has been demonstrated to be secreted by Paneth cells in mice. We have successfully cloned and characterized a new chicken gene (chAng4), found for the first time in a nonmammalian species, from intestinal epithelial and lymphoid cells. Characterization of chAng4 revealed 99% nucleotide and 97% amino acid sequence homology to mouse Ang4. Similar functional regions were identified, suggesting a role in innate immunity and regulation of gut microbiota. Furthermore, the mRNA expression pattern of chAng4 was studied in broilers in the presence or absence of beneficial bacteria (probiotics) and organic acids. The results showed that one-day-old chickens expressed low levels of Ang4 in almost all the evaluated tissues (crop, proventriculus, duodenum, jejunum, ileum, and cecal tonsils), except in the bursa of Fabricius that presented the highest expression level. The addition of probiotics and organic acids for either 7 or 14 consecutive days demonstrated a direct effect of probiotics and organic acids on chAng4 expression; moreover, broilers receiving probiotics and organic acids for only 7 D showed higher levels of chAng4 expression compared with those treated for 14 D. Broilers without treatment had a constant high level of expression in cecal tonsils and bursa. In conclusion, we were able to identify and characterize a new antimicrobial gene in chickens (chAng4) throughout the gastrointestinal tract. chAng4 mRNA gene expression was associated with the presence of naturally occurring and supplemented (probiotic) bacteria. The encoded protein might have a potential bactericidal effect against intestinal nonpathogenic and pathogenic microbes, modulating the intestinal microbiota and the innate immunity, and thereby may help minimize the use of antibiotics in poultry feed.
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Affiliation(s)
- Daniela Losada-Medina
- Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada; Department of Chemistry, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada
| | - Alexander Yitbarek
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Canada
| | - Nauman Nazeer
- Department of Chemistry, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada
| | - Santiago Uribe-Diaz
- Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada; Department of Chemistry, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada
| | - Marya Ahmed
- Department of Chemistry, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada
| | - Juan C Rodriguez-Lecompte
- Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada.
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Bagheri S, Janmohammadi H, Maleki R, Ostadrahimi A, Kianfar R. Laying hen performance, egg quality improved and yolk 5-methyltetrahydrofolate content increased by dietary supplementation of folic acid. ACTA ACUST UNITED AC 2018; 5:130-133. [PMID: 31193894 PMCID: PMC6544570 DOI: 10.1016/j.aninu.2018.05.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 05/09/2018] [Accepted: 05/25/2018] [Indexed: 11/28/2022]
Abstract
This study was performed to evaluate the effect of folic acid (FA) on performance, egg quality and yolk 5-methyltetrahydrofolate (5-MTHF) content. A total of 384 Hy-line W36 strain hens from 52 to 58 weeks of age were randomly assigned to 4 groups, and each group received one of following dietary treatments: 0, 5, 10 and 15 mg FA/kg diet. A completely randomized design was used. Egg production percentage, egg mass and egg weight were increased significantly (P < 0.05) and feed conversion ratio (FCR) was reduced significantly (P < 0.05) by increasing FA content in diets. No significant differences were detected among treatments on egg quality except for shell thickness. The dietary supplementations of laying hens diets with FA significantly increased yolk 5-MTHF content (P = 0.02). Overall, these data demonstrate that dietary supplementation with FA raised 5-MTHF content of yolk and productivity of egg production in laying hens.
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Affiliation(s)
- Sattar Bagheri
- Department of Animal Science, Faculty of Agriculture, University of Tabriz, Tabriz, 5166616471, Iran
| | - Hossein Janmohammadi
- Department of Animal Science, Faculty of Agriculture, University of Tabriz, Tabriz, 5166616471, Iran
| | - Ramin Maleki
- Department of Chromatography, Iranian Academic Center for Education, Culture and Research (ACECR), Urmia, Iran
| | - Alireza Ostadrahimi
- Nutrition Research Center, Tabriz University of Medical Sciences, Tabriz, 5166614711, Iran
| | - Ruhollah Kianfar
- Department of Animal Science, Faculty of Agriculture, University of Tabriz, Tabriz, 5166616471, Iran
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Tsuji A, Noguchi R, Nakamura T, Shibata K. Folic Acid Deficiency Does Not Adversely Affect Oocyte Meiosis in Mice. J Nutr Sci Vitaminol (Tokyo) 2017; 62:375-379. [PMID: 28202841 DOI: 10.3177/jnsv.62.375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Spindle defect and chromosome misalignment occuring in oocyte meiosis induce nondisjunction. Nondisjunction causes Down syndrome, also known as trisomy 21. Folic acid (FA) is an essential nutrient composition for fetal growth and development. It has been reported that FA nutritional status is associated with the risk of Down syndrome. However, to our knowledge, little is known about the effect of FA deficiency on abnormal oocytes (spindle defects, chromosome misalignments and immature oocyte) in vivo. In the present study, we investigate the effects of FA deficiency on oocyte meiosis in female mice. In order to induce FA deficiency in mice, female Crl:CD1 mice were fed a FA-free diet for 58 d. The diet also contained an antibiotic which has functions on limiting FA formation by intestinal microorganisms. The level of FA deficiency was determined by measuring the concentration of FA in the liver, hemocyte, uterus, ovary, and urine. FA concentrations in these samples from the FA-deficient group were 50-90% lower. Despite this, the frequency of abnormal oocytes was no different between the FA-deficient and control groups (20.0% vs 14.6%). According to the past research, FA transporter was strongly expressed in oocytes. Hence, it is possible that FA-free diets may not affect the concentration of oocyte FA in mice. To sum up these data, our study concluded that FA deficiency did not adversely affect oocyte meiosis.
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Affiliation(s)
- Ai Tsuji
- Department of Nutrition, School of Human Cultures, The University of Shiga Prefecture
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Jing M, Munyaka P, Tactacan G, Rodriguez-Lecompte J, O K, House J. Performance, serum biochemical responses, and gene expression of intestinal folate transporters of young and older laying hens in response to dietary folic acid supplementation and challenge with Escherichia coli lipopolysaccharide. Poult Sci 2014; 93:122-31. [DOI: 10.3382/ps.2013-03384] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Reduced expression of folate transporters in kidney of a rat model of folate oversupplementation. GENES AND NUTRITION 2013; 9:369. [PMID: 24306960 DOI: 10.1007/s12263-013-0369-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 11/12/2013] [Indexed: 12/29/2022]
Abstract
Folic acid is the key one-carbon donor required for de novo nucleotide and methionine synthesis. Its deficiency is associated with megaloblastic anemia, cancer and various complications of pregnancy. However, its supplementation results in reduction of neural tube defects and prevention of several types of cancer. The intake of folic acid from fortified food together with the use of nutritional supplements creates a state of folate oversupplementation. Fortification of foods is occurring worldwide with little knowledge of the potential safety and physiologic consequences of intake of such high doses of folic acid. So, we planned to examine the effects of acute and chronic folate oversupplementation on the physiology of renal folate transport in rats. Male Wistar rats were procured and divided into two groups. Rats in group I were given semisynthetic diets containing 2 mg folic acid/kg diet (control) and those in group II were given folate-oversupplemented rat diet, i.e., 20 mg folic acid/kg diet (oversupplemented). Six animals from group I and group II received the treatment for 10 days (acute treatment) and remaining six for 60 days (chronic treatment). In acute folate-oversupplemented rats, 5-[(14)C]-methyltetrahydrofolate uptake was found to be significantly reduced, as compared to chronic folate-oversupplemented and control rats. This reduction in uptake was associated with a significant decrease in the mRNA and protein levels of the folate transporters. Results of the present investigation showed that acute oversupplementation led to a specific and significant down-regulation of renal folate uptake process mediated via transcriptional and translational regulatory mechanism(s).
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Jing M, Gakhar N, Gibson RA, House JD. Dietary and ontogenic regulation of fatty acid desaturase and elongase expression in broiler chickens. Prostaglandins Leukot Essent Fatty Acids 2013; 89:107-13. [PMID: 23809327 DOI: 10.1016/j.plefa.2013.05.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 05/28/2013] [Accepted: 05/30/2013] [Indexed: 11/26/2022]
Abstract
Effects of diet and ontogeny on the expression of fatty acid desaturases and elongases were examined in broiler chickens. In Study 1, 120 day-old male chicks received one of six diets with LA:ALA ranging from 46:4 to 16:34, for 33 days. Total n-6 PUFA decreased, and n-3 PUFA increased in response to a decrease in the dietary LA:ALA. FADS1, FADS2, ELOVL2 and ELOVL5 mRNAs were highest (P<0.05) in birds fed lower LA:ALA diets. In Study 2, 60 day-old male chicks were fed a basal diet, and liver samples were collected on day of hatch, and on days 2, 7, 14, 21 and 35 post-hatch. Total n-6 and n-3 PUFA increased (P<0.01) from days 7 to days 21. FADS1, FADS2 and ELOVL2 mRNAs generally increased (P<0.01) with age. These findings provide evidence for the dietary and developmental regulation of PUFA metabolism in broiler chickens.
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Affiliation(s)
- M Jing
- Department of Animal Science, University of Manitoba, Winnipeg, MB, Canada R3T 2N2
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Post-hatching ontogeny of intestinal proton-coupled folate transporter and reduced folate carrier in broiler chickens. Animal 2013; 7:1659-64. [DOI: 10.1017/s1751731113001213] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Rodríguez-Lecompte JC, Yitbarek A, Brady J, Sharif S, Cavanagh MD, Crow G, Guenter W, House JD, Camelo-Jaimes G. The effect of microbial-nutrient interaction on the immune system of young chicks after early probiotic and organic acid administration1. J Anim Sci 2012; 90:2246-54. [DOI: 10.2527/jas.2011-4184] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
| | - A. Yitbarek
- Department of Animal Science, University of Manitoba, Winnipeg R3T 2N2, Canada
| | - J. Brady
- Department of Animal Science, University of Manitoba, Winnipeg R3T 2N2, Canada
| | - S. Sharif
- Department of Pathobiology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - M. D. Cavanagh
- Department of Animal Science, University of Manitoba, Winnipeg R3T 2N2, Canada
| | - G. Crow
- Department of Animal Science, University of Manitoba, Winnipeg R3T 2N2, Canada
| | - W. Guenter
- Department of Animal Science, University of Manitoba, Winnipeg R3T 2N2, Canada
| | - J. D. House
- Department of Human Nutritional Science, University of Manitoba, Winnipeg R3T 2N2, Canada
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Yitbarek A, Echeverry H, Brady J, Hernandez-Doria J, Camelo-Jaimes G, Sharif S, Guenter W, House J, Rodriguez-Lecompte J. Innate immune response to yeast-derived carbohydrates in broiler chickens fed organic diets and challenged with Clostridium perfringens. Poult Sci 2012; 91:1105-12. [DOI: 10.3382/ps.2011-02109] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Tactacan G, Rodriguez-Lecompte J, O K, House J. The adaptive transport of folic acid in the intestine of laying hens with increased supplementation of dietary folic acid. Poult Sci 2012; 91:121-8. [DOI: 10.3382/ps.2011-01711] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Tactacan G, Rodriguez-Lecompte J, Karmin O, House J. Functional characterization of folic acid transport in the intestine of the laying hen using the everted intestinal sac model. Poult Sci 2011; 90:83-90. [DOI: 10.3382/ps.2010-01029] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Regulatory mechanisms of intestinal folate uptake in a rat model of folate oversupplementation. Br J Nutr 2010; 105:827-35. [PMID: 21092376 DOI: 10.1017/s0007114510004538] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Folic acid is essential for numerous biological functions, ranging from nucleotide biosynthesis to the remethylation of homocysteine. Folic acid is unable to cross the biological membranes by simple diffusion, so there exists a well-developed epithelial folate transport system for the regulation of normal folate homeostasis in the intestine. Any perturbances in the folate uptake system might lead to a state of folate deficiency, which in turn is strongly associated with the risk of various cancers, birth defects and CVD. Countries with obligatory folate fortification of food (USA and Canada) have documented a significant decrease in neural tube defects in newborns. However, the effect of folate oversupplementation on the intestinal absorption of folic acid has not been studied. We studied the process of folate transport and the expression of folate transporters in the rat intestine after folate oversupplementation. Rats were oversupplemented with tenfold the normal requirement of folic acid for periods of 10 and 60 d. Folate uptake in intestinal brush-border membrane vesicles followed saturable kinetics with pH optimum at 5·5. Acute, but not chronic, folate oversupplementation led to a significant down-regulation in intestinal folate uptake at acidic pH optima and was associated with a decrease in Vmax without any significant change in the Km of the folate uptake process. The decrease in folate uptake was also associated with the down-regulation in the protein levels of major folate transporters, proton-coupled folate transporter (PCFT) and reduced folate carrier (RFC), without altering their mRNA levels. Hence, it was concluded that acute folate oversupplementation results in a significant decrease in intestinal folate uptake by down-regulating the expressions of RFC and PCFT, via some post-transcriptional or translational mechanisms.
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Jing M, Tactacan G, Rodriguez-Lecompte J, Kroeker A, House J. Proton-coupled folate transporter (PCFT): molecular cloning, tissue expression patterns and the effects of dietary folate supplementation on mRNA expression in laying hens. Br Poult Sci 2010; 51:635-8. [DOI: 10.1080/00071668.2010.508490] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Tactacan G, Jing M, Thiessen S, Rodriguez-Lecompte J, O’Connor D, Guenter W, House J. Characterization of folate-dependent enzymes and indices of folate status in laying hens supplemented with folic acid or 5-methyltetrahydrofolate. Poult Sci 2010; 89:688-96. [DOI: 10.3382/ps.2009-00417] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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