Neural tube defects, folic acid and methylation.
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ABSTRACT:
SUBMITTER: Imbard A
PROVIDER: S-EPMC3799525 | biostudies-literature | 2013 Sep
REPOSITORIES: biostudies-literature
Publications
Neural tube defects, folic acid and methylation.
Imbard Apolline A Benoist Jean-François JF Blom Henk J HJ
International journal of environmental research and public health 20130917 9
Neural tube defects (NTDs) are common complex congenital malformations resulting from failure of the neural tube closure during embryogenesis. It is established that folic acid supplementation decreases the prevalence of NTDs, which has led to national public health policies regarding folic acid. To date, animal studies have not provided sufficient information to establish the metabolic and/or genomic mechanism(s) underlying human folic acid responsiveness in NTDs. However, several lines of evid ...[more]
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Project description:The Mediterranean diet has been for a very long time the basis of food habits all over the countries of the Mediterranean basin, originally founded on rural models and low consumption of meat products and high-fat/high-processed foods. However, in the modern era, the traditional Mediterranean diet pattern is now progressively eroding due to the widespread dissemination of the Western-type economy, life-style, technology-driven culture, as well as the globalisation of food production, availability and consumption, with consequent homogenisation of food culture and behaviours. This transition process may affect many situations, including pregnancy and offspring's health. The problem of the diet during pregnancy and the proper intake of nutrients are nowadays a very current topic, arousing much debate. The Mediterranean dietary pattern, in particular, has been associated with the highest risk reduction of major congenital anomalies, like the heterogeneous class of neural tube defects (NTDs). NTDs constitute a major health burden (0.5-2/1000 pregnancies worldwide) and still remain a preventable cause of still birth, neonatal and infant death, or significant lifelong disabilities. Many studies support the finding that appropriate folate levels during pregnancy may confer protection against these diseases. In 1991 one randomised controlled trial (RCT) demonstrated for the first time that periconceptional supplementation of folic acid is able to prevent the recurrence of NTDs, finding confirmed by many other subsequent studies. Anyway, the high rate of unplanned/unintended pregnancies and births and other issues hindering the achievement of adequate folate levels in women in childbearing age, induced the US government and many other countries to institute mandatory food fortification with folic acid. The actual strategy adopted by European Countries (including Italy) suggests that women take 0,4 mg folic acid/die before conception. The main question is which intervention, between folic acid supplementation, foods fortification or both, linked to a healthy life-style and diet pattern may represent the best method in preventing NTDs. The aim of this review is to describe the actual situation in NTDs prevention, with a special attention to the Italiancontext concerning this delicate and controversial subject.
| S-EPMC5561554 | biostudies-other
Project description:BackgroundHistorically, neural tube defects (NTDs) have predominated in female infants but the reasons remain unclear. In South America, the pre- folic acid fortification (FAF) rates of NTDs were around 18/10,000 births for females and 12/10,000 births for males, with an estimated sex ratio (male/female) of 0.67. During the post- FAF period, unpublished routine reports have indicated changes in the sex ratio for these defects while some descriptive reports are controversial. To date and to our knowledge, however, no studies specifically focusing on these changes to test this hypothesis directly have been undertaken. The aim of this study was to analyze changes in the sex ratio of infants with NTDs after FAF in South American countries.Materials and methodsWith a descriptive cross-sectional study design, 2,597 infants with isolated NTDs born between 1990 and 2013 in 3 countries participating in the Latin American Collaborative Study of Congenital Malformations (ECLAMC) network were included: (Chile N = 521 and Argentina N = 1,619 [with FAF policies]; Venezuela N = 457 [without FAF policies; used as control]; total births = 2,229,561). The differences-in-differences method and Poisson regressions were used to evaluate the sex ratio shift from female to male before vs. after FAF, and to assess whether these differences were related to the fortification.Results and conclusionsIn Chile and Argentina the prevalence of NTDs, particularly anencephaly and cervico-thoracic spina bifida, showed a greater reduction rate in females than in males after FAF, resulting in a change of the sex ratio of infants with NTDs. Some mechanisms possibly involved in this differential reduction are proposed which might be useful to identify the pathogenesis of NTDs as a whole and specifically of those susceptible to the protective effect of folic acid.
| S-EPMC5851584 | biostudies-literature
Project description:Closure of the neural tube during embryogenesis is a crucial step in development of the central nervous system. Failure of this process results in neural tube defects, including spina bifida and anencephaly, which are among the most common birth defects worldwide. Maternal use of folic acid supplements reduces risk of neural tube defects but a proportion of cases are not preventable. Folic acid is thought to act through folate one-carbon metabolism, which transfers one-carbon units for methylation reactions and nucleotide biosynthesis. Hence suboptimal performance of the intervening reactions could limit the efficacy of folic acid. We hypothesized that direct supplementation with nucleotides, downstream of folate metabolism, has the potential to support neural tube closure. Therefore, in a mouse model that exhibits folic acid-resistant neural tube defects, we tested the effect of specific combinations of pyrimidine and purine nucleotide precursors and observed a significant protective effect. Labelling in whole embryo culture showed that nucleotides are taken up by the neurulating embryo and incorporated into genomic DNA. Furthermore, the mitotic index was elevated in neural folds and hindgut of treated embryos, consistent with a proposed mechanism of neural tube defect prevention through stimulation of cellular proliferation. These findings may provide an impetus for future investigations of supplemental nucleotides as a means to prevent a greater proportion of human neural tube defects than can be achieved by folic acid alone.
| S-EPMC3754462 | biostudies-literature
Project description:PURPOSE:Previous studies have shown an association between maternal fever in early pregnancy and neural tube defects (NTDs) such as spina bifida. Periconceptional folic acid intake has been shown to reduce the risk of these outcomes. METHODS:Using data from the Slone Epidemiology Center Birth Defects Study (1998-2015), we examined the impact of folic acid on the relationship between maternal fever in the periconceptional period (28 days before and after the last menstrual period) and NTDs. Logistic regression models were used to calculate adjusted odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS:Mothers of 375 cases and 8247 nonmalformed controls were included. We observed an elevated risk for NTDs for fever in the periconceptional period (OR: 2.4; 95% CI: 1.5-4.0). This association was weaker for mothers who reported consuming the recommended amount of folic acid (?400 ?g per day; OR: 1.8; 95% CI: 0.8-4.0) than mothers with low folic acid intake (<400 ?g per day; OR: 4.2; 95% CI: 2.2-8.2). CONCLUSIONS:Our data support an association between maternal periconceptional fever and an increased risk for NTDs and also provide evidence that this association was attenuated for mothers who reported consuming folic acid at recommended levels in the periconceptional period.
| S-EPMC5824687 | biostudies-literature
Project description:BACKGROUND:Women with a previous neural tube defect (NTD)-affected pregnancy are recommended to consume 4,000??g daily folic acid (FA) for prevention (10 times the general-population recommendation). Protection from doses between 400 and 4,000??g for this and other higher risk groups is unclear. METHODS:In the case-control Slone Birth Defects Study (1988-2015), we examined the associations between periconceptional FA doses and NTDs among four higher risk groups: NTD family history, periconceptional antiepileptic drug exposure (AED), pregestational diabetes, and prepregnancy obesity. Mothers completed standardized interviews about pregnancy events and exposures. FA categorizations were based on (a) supplements only and (b) supplements and diet ("total folate"). We estimated odds ratios (ORs) and 95% confidence intervals (CIs) (adjusted for age and study center) using logistic regression. RESULTS:Cases and controls included: 45 and 119 with family history, 25 and 108 with AED exposure, 12 and 63 with pregestational diabetes, 111 and 1,243 with obesity. Daily FA supplementation was associated with lower NTD risk compared to no supplementation (adjusted ORs were 0.33 [95% CI 0.13, 0.76] for family history, 0.31 [0.09, 0.95] for AED exposure, 0.25 [0.04, 1.05] for pregestational diabetes, 0.65 [0.40, 1.04] for obesity). Though estimates were imprecise, as total folate increased stronger point estimates were observed, notably among family history. No mothers with a prior NTD-affected pregnancy supplemented with 4,000??g. CONCLUSIONS:Our findings reinforce that all women of childbearing potential should consume at least 400??g FA/day to protect against NTDs. Higher risk groups may benefit from higher doses.
| S-EPMC7186568 | biostudies-literature
Project description:BACKGROUND:Neural tube defects (NTDs) are clinically significant congenital malformations which are known to be folic acid (FA) responsive, such that supplementation significantly reduces the prevalence of NTDs. Nonetheless, some individuals fail to respond to FA supplementation; hence NTDs remain a significant public health concern. The mechanisms that underlie the beneficial effects of FA supplementation remain poorly understood. Mouse models have been used extensively to study the mechanisms driving neural tube closure (NTC). METHODS:Microarray data of GSE51285 was downloaded from the NCBI GEO database, which contains the RNA expression profiles of livers from five NTD mouse mutants (heterozygous females) and their corresponding wildtype (WT) controls. Those five NTD mutants have different responsiveness to FA supplementation. The differentially expressed genes (DEGs) between NTD heterozygous and WT mice, as well as the DEGs between FA-responsive and FA-resistant mutants were carefully examined. Weighted gene correlation network analysis (WGCNA) was performed in order to identify genes with high correlations to either FA responsiveness or NTDs, respectively. RESULTS:In total, we identified 18 genes related to the pathogenesis of NTDs, as well as 55 genes related to FA responsiveness. Eight more candidate genes (Abcc3, Gsr, Gclc, Mthfd1, Gart, Bche, Slc25a32, and Slc44a2) were identified by examining the DEGs of those genes involved in the extended folate metabolic pathway between FA-responsive and FA-resistant mutants. CONCLUSIONS:Those genes are involved in mitochondrial choline metabolism, de novo purine synthesis, and glutathione generation, suggesting that formate, choline, and manipulating antioxidant levels may be effective interventions in FA-resistant NTDs.
| S-EPMC6320695 | biostudies-literature
Project description:Neural tube defects (NTDs), including spina bifida and anencephaly, are among the most common birth defects worldwide, but their underlying genetic and cellular causes are not well understood. Some NTDs are preventable by supplemental folic acid. However, despite widespread use of folic acid supplements and implementation of food fortification in many countries, the protective mechanism is unclear. Pax3 mutant (splotch; Sp2H ) mice provide a model in which NTDs are preventable by folic acid and exacerbated by maternal folate deficiency. Here, we found that cell proliferation was diminished in the dorsal neuroepithelium of mutant embryos, corresponding to the region of abolished Pax3 function. This was accompanied by premature neuronal differentiation in the prospective midbrain. Contrary to previous reports, we did not find evidence that increased apoptosis could underlie failed neural tube closure in Pax3 mutant embryos, nor that inhibition of apoptosis could prevent NTDs. These findings suggest that Pax3 functions to maintain the neuroepithelium in a proliferative, undifferentiated state, allowing neurulation to proceed. NTDs in Pax3 mutants were not associated with abnormal abundance of specific folates and were not prevented by formate, a one-carbon donor to folate metabolism. Supplemental folic acid restored proliferation in the cranial neuroepithelium. This effect was mediated by enhanced progression of the cell cycle from S to G2 phase, specifically in the Pax3 mutant dorsal neuroepithelium. We propose that the cell-cycle-promoting effect of folic acid compensates for the loss of Pax3 and thereby prevents cranial NTDs.
| S-EPMC6899032 | biostudies-literature
Project description:OBJECTIVE:To find out the status of folic acid supplementation among women, to evaluate the prevention effects on neural tube defects (NTDs), and to explore the factors impact on folic acid supplementation compliance. METHODS:Based on the routine data of 92 121 women in prenatal health care and birth defect surveillance system in Tongzhou District of Beijing from 2013 to 2018, we described the prevalence of periconceptional folic acid supplementation, pre-pregnancy folic acid supplementation and regularly folic acid supplementation (compliance supplementation). Trend ?2 tests were used to evaluate the change of folic acid supplementation prevalence. The prevalence difference among the women with folic acid supplementation and without supplementation were tested with Fisher's exact test. Factors asso-ciated with folic acid supplementation compliance rate were analyzed with univariate and multivariate Logistic regression model. RESULTS:The prevalence of periconceptional folic acid supplementation during the six years was 90.08% and it was increased from 2013 to 2018, but the rate of pre-pregnancy and regular supplementation was only 41.5% and declined from 2013 to 2018, especially 2013 to 2015. The prevalence of NTDs among the fetuses whose mothers took folic acid during periconceptional period was 5.5/10 000, while the prevalence for the fetuses whose mothers did not take folic acid was 19.7/10 000 (P < 0.001), the rates ratio was 27.9% (?2=23.74, P < 0.001). The difference between the prevalence of NTDs among the fetuses whose mothers took folic acid only and multiple micronutrients was not statistically significant. After controlling the confounding factors, it was found that the compliant folic acid supplementation rates in women, whose household registrations were outside Beijing and whose education levels were junior high school or below, and who were younger than 25 years old, and who were multiparas and who were pre-pregnancy underweight or obese, were lower than those of the corresponding control groups (P < 0.05). CONCLUSION:The rate of folic acid supplementation among women in Tongzhou District of Beijing was relatively high, but their compliance was poor. Women who did not take folic acid during periconception seriously affected the prevention effect of NTDs. We should focus on women who are younger than 25 years old, lower educated, pre-pregnancy underweight or obese, multiparas and nonlocal household registers, in order to improve the periconceptional folic acid supplementation compliance and improve the effects of NTDs prevention.
| S-EPMC7433619 | biostudies-literature
Project description:Despite efforts to tackle folate deficiency and Neural Tube Defects (NTDs) through folic acid fortification, its implementation is still lacking where it is needed most, highlighting the need for studies that evaluate the effectiveness of folic acid fortified wheat flour in a poor, rural, high-risk, NTD region of China. One of the most affected regions, Shanxi Province, was selected as a case study. A community intervention was carried out in which 16,648 women of child-bearing age received fortified flour (eight villages) and a control group received ordinary flour (three villages). NTD birth prevalence and biological indicators were measured two years after program initiation at endline only. The effect on the NTD burden was calculated using the disability-adjusted life years (DALYs) method. In the intervention group, serum folate level was higher than in the control group. NTDs in the intervention group were 68.2% lower than in the control group (OR = 0.313, 95% CI = 0.207-0473, p < 0.001). In terms of DALYs, burden in intervention group was approximately 58.5% lower than in the control group. Flour fortification was associated with lower birth prevalence and burden of NTDs in economically developing regions with a high risk of NTDs. The positive findings confirm the potential of fortification when selecting an appropriate food vehicle and target region. As such, this study provides support for decision makers aiming for the implementation of (mandatory) folic acid fortification in China.
| S-EPMC4808880 | biostudies-literature
Project description:BackgroundTo investigate the association of folate metabolism gene polymorphism with neural tube defects (NTDs) in Chinese population.MethodsThe subjects were divided into two groups, 495 children with NTDs (NTD group) and 255 healthy children (control group).ResultsThe levels of folic acid, s-adenosine methionine (SAM), and Sam/s-adenosine homocysteine (SAH) in NTD group were lower than those in control group. There were significant differences in hey, SAH, and Sam levels between two groups, but there was no significant difference in folic acid content. High fever in early pregnancy, taking antiepileptic drugs, father's exposure to organic solvents, folic acid deficiency, and mother's diabetes were the important risk factors in NTDs. MTHFR 677C > T gene was a risk factor for NTD in children, while 1298A > C gene was a protective factor.ConclusionFolic acid metabolism markers were different in NTD children and their mothers, and the overall trend showed that folate, SAM, and SAM/SAH levels were decreased, while Hcy and SAH levels were increased; MTHFR 677C > T gene of SNPs was a risk factor for the occurrence of NTDs, and MTHFR 1298A > C gene was a protective factor, and the environmental risk factor had a synergistic effect on occurrence of NTDs.
| S-EPMC10290577 | biostudies-literature