RELATIONSHIPS BETWEEN BIOTIN AND VITAMIN B12. EFFECTS OF BIOTIN AND VITAMIN B12 ON FOLIC ACID METABOLISM.
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ABSTRACT:
SUBMITTER: MARCHETTI M
PROVIDER: S-EPMC1206614 | biostudies-other | 1965 Mar
REPOSITORIES: biostudies-other
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Project description:1. Metabolism of folate was studied in six ewes in an advanced state of vitamin B(12) deficiency as judged by voluntary food intake and in their pair-fed controls receiving vitamin B(12). A group of four animals that were maintained throughout the experiment at pasture was also studied. 2. After 34-40 weeks on the cobalt-deficient diet urinary excretion of formiminoglutamate by four deficient animals was about 3.2mmol/day and this was not significantly decreased by injection of three of them with about 4.5mug of [2-(14)C]folate/kg body weight per day for 5 days. Three days after the last injection retention of [2-(14)C]folate by the livers of the deficient animals (5.5% of the dose) was lower than that of their pair-fed controls (26% of the dose) but there was no evidence of net retention of injected folate in the livers of either group. Urinary excretion of (14)C indicated that renal clearance of folate may have been impaired in very severe vitamin B(12) deficiency. 3. As estimated by microbiological assays total folates in the livers of animals at pasture (12.9mug/g) included about 24% of 5-methyltetrahydrofolate as compared with about 72% of a total of 12.5mug/g in three further ewes fed on a stock diet of wheaten hay-chaff and lucerne-chaff. Liver folates of vitamin B(12)-deficient animals (0.5mug/g) included about 88% of 5-methyltetrahydrofolate as compared with about 51% of a total of 5.2mug/g in pair-fed animals treated with vitamin B(12). 4. Chromatography of liver folates of the pair-fed animals permitted quantitative estimates of the pteroylglutamates present. The results showed that the vitamin B(12)-deficient livers were more severely depleted of tetrahydrofolates and formyltetrahydrofolates than of methyltetrahydrofolates and that as the deficiency developed they were more severely depleted of the higher polyglutamates than of the monoglutamate within each of these classes. Results from animals injected with [2-(14)C]folate indicated an impairment of the exchange between pteroylmonoglutamates and pteroylpolyglutamates in the livers of deficient animals. 5. In vitamin B(12)-deficient animals with food intakes below 200g/day some of the liver folates were not completely reduced and some degradation of pteroylpolyglutamates was detected. The latter condition may have been associated with fatty liver. 6. The results are discussed in relation to current theories of vitamin B(12)-folate interactions.
| S-EPMC1165953 | biostudies-other
Project description:1. The effects of injected l-methionine (2g every second day for 28 days) on liver folates and other constituents of liver associated with folate metabolism were studied in vitamin B(12)-deficient ewes and their pair-fed controls receiving vitamin B(12). The dose rate of methionine used was sufficient to restore almost to normal the elevated excretion in the urine of formiminoglutamate in the deficient animals. 2. Liver folates active for Lactobacillus casei, Streptococcus faecalis R and Pediococcus cerevisiae were severely depressed in deficient livers and were partly restored by methionine. Analysis of the folates after ion-exchange chromatography showed that the major effect of methionine was to increase the concentrations of tetrahydrofolates and formyltetrahydrofolates. Methyltetrahydrofolates were also increased, but there was no effect of methionine on the small amounts of incompletely reduced folates present in deficient livers. The folates present were predominantly penta-, hexa- and hepta-glutamates whether or not animals received vitamin B(12) or methionine. 3. Concentrations of ATP, NAD(+), NADH and NADPH were lower in freeze-clamped liver from vitamin B(12)-deficient sheep than in liver from pair-fed, vitamin B(12)-treated sheep. These changes were not affected by methionine which was also without effect on the elevated K(+)/Na(+) ratios found in deficient livers. 4. The livers of vitamin B(12)-deficient animals contained lower concentrations of choline and higher concentrations of lipid than their pair-fed controls. These effects were reversed by methionine.
| S-EPMC1168216 | biostudies-other
Project description:Patients affected by chronic kidney disease (CKD) or end-stage renal disease (ESRD) experience a huge cardiovascular risk and cardiovascular events represent the leading causes of death. Since traditional risk factors cannot fully explain such increased cardiovascular risk, interest in non-traditional risk factors, such as hyperhomocysteinemia and folic acid and vitamin B12 metabolism impairment, is growing. Although elevated homocysteine blood levels are often seen in patients with CKD and ESRD, whether hyperhomocysteinemia represents a reliable cardiovascular and mortality risk marker or a therapeutic target in this population is still unclear. In addition, folic acid and vitamin B12 could not only be mere cofactors in the homocysteine metabolism; they may have a direct action in determining tissue damage and cardiovascular risk. The purpose of this review was to highlight homocysteine, folic acid and vitamin B12 metabolism impairment in CKD and ESRD and to summarize available evidences on hyperhomocysteinemia, folic acid and vitamin B12 as cardiovascular risk markers, therapeutic target and risk factors for CKD progression.
| S-EPMC6413093 | biostudies-other
Project description:The fertility of dairy cows is challenged during early lactation and better nutritional strategies need to be developed to address this issue. Combined supplementation of folic acid and vitamin B12 improves energy metabolism in the dairy cow during early lactation. Therefore, the present study was undertaken to explore the effects of this supplement on gene expression in granulosa cells from the dominant follicle during the postpartum period. Multiparous Holstein cows received weekly intramuscular injection of 320 mg folic acid and 10 mg vitamin B12 (treated group) beginning 24 (SD 4) d before calving until 56 d after calving, whereas the control group received saline. The urea plasma concentration was significantly decreased during the pre-calving period, and the concentration of both folate and vitamin B12 were increased in treated animals. Milk production and dry matter intake were not significantly different between the two groups. Plasma concentrations of folates and vitamin B12 were increased in vitamin-treated animals. Daily dry matter intake was not significantly different between the 2 groups before (13.5 kg SE 0.5) and after (23.6 kg SE 0.9) calving. Average energy-corrected milk tended to be greater in vitamin-treated cows, 39.7 (SE 1.4) and 38.1 (SE 1.3) kg/d for treated and control cows, respectively. After calving, average plasma concentration of BHBA tended to be lower in cows injected with the vitamin supplement, 0.47 (SE 0.04) vs. 0.55 (SE 0.03) for treated and control cows, respectively. The ovarian follicle ? 12 mm in diameter was collected by ovarian pick-up after estrus synchronization. Recovered follicular fluid volumes were greater in the vitamin-treated group. A microarray platform was used to investigate the impact of treatment on gene expression of granulosa cells. Lower expression of genes involved in the cell cycle and higher expression of genes associated with granulosa cell differentiation prior to ovulation were observed. Selected candidate genes were analyzed by reverse transcription quantitative polymerase chain reaction. Although the effects of intramuscular injections of folic acid and vitamin B12 on lactational performance and metabolic status of animals were limited, Ingenuity Pathway Analysis of gene expression in granulosa cells suggests a stimulation of cell differentiation in vitamin-treated cows, which may be the result of an increase in LH secretion. Two conditions experiment (Control and Treated). Granulosa cells from the 66h post second PGF2alpha injection. Biological replicates: 3 from each time point. Two technical replicates for each comparison (dye-swap).
2015-09-15 | E-GEOD-72038 | biostudies-arrayexpress
Project description:1. A study was made of the effects of injected l-methionine on the activity of several enzymes of folate metabolism, and on the transport of methotrexate in liver preparations from vitamin B(12)-deficient ewes and their pair-fed controls receiving vitamin B(12). 2. The activities of dihydrofolate reductase (EC 1.5.1.3) and 5-methyltetrahydrofolate-homocysteine transmethylase were significantly decreased in the liver of vitamin B(12)-deficient animals, but were unaffected by l-methionine. 3. The concentration of S-adenosyl-l-methionine in the liver of deficient animals was about one-half of that in normal animals, and was restored to normal by either vitamin B(12) or l-methionine. 4. Methylenetetrahydrofolate reductase (EC 1.1.1.68) from sheep liver was inhibited by S-adenosyl-l-methionine in vitro, but not by concentrations of S-adenosyl-l-methionine found in the liver of vitamin B(12)-deficient animals after injection of physiological amounts of l-methionine. 5. Pteroylpolyglutamate synthetase activity was significantly increased in the liver of vitamin B(12)-deficient animals, and was decreased by intravenous injections of l-methionine. 6. l-Methionine injections increased the initial rate of uptake of methotrexate in liver slices from deficient animals and acted synergistically with vitamin B(12) to increase the quantity taken up in 40min. The failure of folate metabolism in vitamin B(12) deficiency can be satisfactorily explained if l-methionine similarly affects the membrane transport of naturally occurring folates. 7. Further details of the results have been deposited as Supplementary Publication SUP 50028 (4 pages) at the British Library (Lending Division), (formerly the National Lending Library for Science and Technology), Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies may be obtained on the terms given in Biochem. J. (1973) 131, 5.
| S-EPMC1168217 | biostudies-other
Project description:The fertility of dairy cows is challenged during early lactation and better nutritional strategies need to be developed to address this issue. Combined supplementation of folic acid and vitamin B12 improves energy metabolism in the dairy cow during early lactation. Therefore, the present study was undertaken to explore the effects of this supplement on gene expression in granulosa cells from the dominant follicle during the postpartum period. Multiparous Holstein cows received weekly intramuscular injection of 320 mg folic acid and 10 mg vitamin B12 (treated group) beginning 24 (SD 4) d before calving until 56 d after calving, whereas the control group received saline. The urea plasma concentration was significantly decreased during the pre-calving period, and the concentration of both folate and vitamin B12 were increased in treated animals. Milk production and dry matter intake were not significantly different between the two groups. Plasma concentrations of folates and vitamin B12 were increased in vitamin-treated animals. Daily dry matter intake was not significantly different between the 2 groups before (13.5 kg SE 0.5) and after (23.6 kg SE 0.9) calving. Average energy-corrected milk tended to be greater in vitamin-treated cows, 39.7 (SE 1.4) and 38.1 (SE 1.3) kg/d for treated and control cows, respectively. After calving, average plasma concentration of BHBA tended to be lower in cows injected with the vitamin supplement, 0.47 (SE 0.04) vs. 0.55 (SE 0.03) for treated and control cows, respectively. The ovarian follicle ? 12 mm in diameter was collected by ovarian pick-up after estrus synchronization. Recovered follicular fluid volumes were greater in the vitamin-treated group. A microarray platform was used to investigate the impact of treatment on gene expression of granulosa cells. Lower expression of genes involved in the cell cycle and higher expression of genes associated with granulosa cell differentiation prior to ovulation were observed. Selected candidate genes were analyzed by reverse transcription quantitative polymerase chain reaction. Although the effects of intramuscular injections of folic acid and vitamin B12 on lactational performance and metabolic status of animals were limited, Ingenuity Pathway Analysis of gene expression in granulosa cells suggests a stimulation of cell differentiation in vitamin-treated cows, which may be the result of an increase in LH secretion.
2015-09-15 | GSE72038 | GEO
Project description:ContextFolate, vitamin B(6), and vitamin B(12) are thought to play an important role in cancer prevention.ObjectiveTo evaluate the effect of combined folic acid, vitamin B(6), and vitamin B(12) treatment on cancer risk in women at high risk for cardiovascular disease.Design, setting, and participantsIn the Women's Antioxidant and Folic Acid Cardiovascular Study, 5442 US female health professionals aged 42 years or older, with preexisting cardiovascular disease or 3 or more coronary risk factors, were randomly assigned to receive either a daily combination of folic acid, vitamin B(6), and vitamin B(12) or a matching placebo. They were treated for 7.3 years from April 1998 through July 31, 2005.InterventionDaily supplementation of a combination of 2.5 mg of folic acid, 50 mg of vitamin B(6), and 1 mg of vitamin B(12) (n = 2721) or placebo (n = 2721).Main outcome measuresConfirmed newly diagnosed total invasive cancer or breast cancer.ResultsA total of 379 women developed invasive cancer (187 in the active treatment group and 192 in the placebo group). Compared with placebo, women receiving the active treatment had similar risk of developing total invasive cancer (101.1/10,000 person-years for the active treatment group vs 104.3/10,000 person-years for placebo group; hazard ratio [HR], 0.97; 95% confidence interval [CI], 0.79-1.18; P = .75), breast cancer (37.8/10,000 person-years vs 45.6/10,000 person-years, respectively; HR, 0.83; 95% CI, 0.60-1.14; P = .24), or any cancer death (24.6/10,000 person-years vs 30.1/10,000 person-years, respectively; HR, 0.82; 95% CI, 0.56-1.21; P = .32).ConclusionCombined folic acid, vitamin B(6), and vitamin B(12) treatment had no significant effect on overall risk of total invasive cancer or breast cancer among women during the folic acid fortification era.Trial registrationclinicaltrials.gov Identifier: NCT00000541.
| S-EPMC2593624 | biostudies-literature
Project description:BackgroundFolate and its synthetic form folic acid function as donor of one-carbon units and have been, together with other B-vitamins, implicated in programming of epigenetic processes such as DNA methylation during early development. To what extent regulation of DNA methylation can be altered via B-vitamins later in life, and how this relates to health and disease, is not exactly known. The aim of this study was to identify effects of long-term supplementation with folic acid and vitamin B12 on genome-wide DNA methylation in elderly subjects. This project was part of a randomized, placebo-controlled trial on effects of supplemental intake of folic acid and vitamin B12 on bone fracture incidence (B-vitamins for the PRevention Of Osteoporotic Fractures (B-PROOF) study). Participants with mildly elevated homocysteine levels, aged 65-75 years, were randomly assigned to take 400 μg folic acid and 500 μg vitamin B12 per day or a placebo during an intervention period of 2 years. DNA was isolated from buffy coats, collected before and after intervention, and genome-wide DNA methylation was determined in 87 participants (n = 44 folic acid/vitamin B12, n = 43 placebo) using the Infinium HumanMethylation450 BeadChip.ResultsAfter intervention with folic acid and vitamin B12, 162 (versus 14 in the placebo group) of the 431,312 positions were differentially methylated as compared to baseline. Comparisons of the DNA methylation changes in the participants receiving folic acid and vitamin B12 versus placebo revealed one single differentially methylated position (cg19380919) with a borderline statistical significance. However, based on the analyses of differentially methylated regions (DMRs) consisting of multiple positions, we identified 6 regions that differed statistically significantly between the intervention and placebo group. Pronounced changes were found for regions in the DIRAS3, ARMC8, and NODAL genes, implicated in carcinogenesis and early embryonic development. Furthermore, serum levels of folate and vitamin B12 or plasma homocysteine were related to DNA methylation of 173, 425, and 11 regions, respectively. Interestingly, for several members of the developmental HOX genes, DNA methylation was related to serum levels of folate.ConclusionsLong-term supplementation with folic acid and vitamin B12 in elderly subjects resulted in effects on DNA methylation of several genes, among which genes implicated in developmental processes.
| S-EPMC4644301 | biostudies-literature
Project description:Despite broad appreciation of their clinical utility, it has been unclear how vitamin B12 and folic acid (FA) function at the molecular level to directly prevent their hallmark symptoms of deficiency like anemia or birth defects. To this point, B12 and FA have largely been studied as cofactors for enzymes in the one-carbon (1C) cycle in facilitating the de novo generation of nucleotides and methylation of DNA and protein. Here, we report that B12 and FA function as natural antagonists of aryl hydrocarbon receptor (AhR). Our studies indicate that B12 and FA bind AhR directly as competitive antagonists, blocking AhR nuclear localization, XRE binding, and target gene induction mediated by AhR agonists like 2,3,7,8-tetrachlorodibenzodioxin (TCDD) and 6-formylindolo[3,2-b]carbazole (FICZ). In mice, TCDD treatment replicated many of the hallmark symptoms of B12/FA deficiency and cotreatment with aryl hydrocarbon portions of B12/FA rescued mice from these toxic effects. Moreover, we found that B12/FA deficiency in mice induces AhR transcriptional activity and accumulation of erythroid progenitors and that it may do so in an AhR-dependent fashion. Consistent with these results, we observed that human cancer samples with deficient B12/FA uptake demonstrated higher transcription of AhR target genes and lower transcription of pathways implicated in birth defects. In contrast, there was no significant difference observed between samples with mutated and intact 1C cycle proteins. Thus, we propose a model in which B12 and FA blunt the effect of natural AhR agonists at baseline to prevent the symptoms that arise with AhR overactivation.
| S-EPMC7355044 | biostudies-literature
Project description:PurposeTo examine the incidence of cataract and cataract extraction in a trial of folic acid and vitamins B6 and B12.MethodsIn a randomized, double-masked, placebo-controlled trial, 5442 female health professionals aged 40 years or older with preexisting cardiovascular disease (CVD) or three or more CVD risk factors were randomly assigned to receive a combination of folic acid (2.5 mg/day), vitamin B6 (50 mg/day), and vitamin B12 (1 mg/day), or placebo. A total of 3925 of these women did not have a diagnosis of cataract at baseline and were included in this analysis. The primary endpoint was age-related cataract, defined as an incident age-related lens opacity, responsible for a reduction in best-corrected visual acuity to 20/30 or worse, based on self-report confirmed by medical record review. Extraction of incident age-related cataract was a secondary endpoint of the trial.ResultsDuring an average of 7.3 years of treatment and follow-up, 408 cataracts and 275 cataract extractions were documented. There were 215 cataracts in the combination treatment group and 193 in the placebo group (hazard ratio, HR, 1.10, 95% confidence interval, CI, 0.90-1.33; p = 0.36). For the secondary endpoint of cataract extraction, there were 155 in the combination treatment group and 120 in the placebo group (HR 1.28, 95% CI 1.01-1.63; p = 0.04).ConclusionsIn this large-scale randomized trial of women at high risk of CVD, daily supplementation with a combination of folic acid, vitamin B6, and vitamin B12 had no significant effect on cataract, but may have increased the risk of cataract extraction.
| S-EPMC4948058 | biostudies-literature