| 1. |
- Gardner, Renee M., et al.
(författare)
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Arsenic methylation efficiency increases during the first trimester of pregnancy independent of folate status
- 2011
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Ingår i: Reproductive Toxicology. - : Elsevier BV. - 0890-6238 .- 1873-1708. ; 31:2, s. 210-218
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Tidskriftsartikel (refereegranskat)abstract
- Exposure to inorganic arsenic during pregnancy may negatively influence the offspring, though efficient metabolism of arsenic to dimethylarsinic acid (DMA) likely reduces the health risks. This study aimed to evaluate methylation of arsenic over the entire pregnancy and the influence of nutritional status. We studied longitudinally the arsenic metabolite pattern in the urine of 324 pregnant women exposed to arsenic via drinking water and food in rural Bangladesh. Metabolism of arsenic to DMA increased markedly over the course of pregnancy, with the greatest improvement occurring in the first trimester, along with a marked decrease in the most risk-associated monomethylated metabolite. This improvement in methylation was not associated with nutritional status, including vitamin B(12) and folate. Efficient methylation to DMA was associated with improved urinary excretion of arsenic, relative to blood arsenic concentrations, indicating that micronutrient-independent up-regulation of arsenic metabolism already in early pregnancy may provide protection for the fetus.
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| 2. |
- Gardner, Renee M, et al.
(författare)
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Pregnancy and the methyltransferase genotype independently influence the arsenic methylation phenotype.
- 2012
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Ingår i: Pharmacogenetics & Genomics. - 1744-6872 .- 1744-6880. ; 22:7, s. 508-516
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: The methyltransferase genotype and pregnancy both influence the arsenic metabolism phenotype, but it is unknown whether these factors interact, explaining the drastic changes in the efficiency of arsenic metabolism observed among pregnant women. The aim of this study was to evaluate the relative contribution of the methyltransferase genotype and pregnancy to the arsenic metabolism phenotype. METHODS: We studied longitudinally the arsenic metabolite pattern in urine (at approximately gestational weeks 8, 14, and 30) of 303 women exposed to arsenic through drinking water and food in rural Bangladesh. Urinary arsenic metabolites were measured by high-performance liquid chromatography-inductively coupled plasma mass spectrometry. Data were available on genotypes for 16 polymorphisms, combined as haplotypes, in three methyltransferases: arsenic(+III)methyltransferase (AS3MT) and DNA-methyltransferases 1a and 3b (DNMT1a and DNMT3b). Changes in the arsenic metabolite pattern over time were evaluated by haplotype using logistic quantile regression. RESULTS: All four AS3MT haplotypes and all three DNMT1a haplotypes significantly influenced the metabolite pattern in the pregnant women, with consistent effects of genotype over the entire course of pregnancy. No interaction was found between the haplotypes and pregnancy-related changes in the arsenic metabolism phenotype. DNMT3b haplotypes did not significantly influence the metabolite pattern. We observed a pregnancy-attributable decrease of 5.7% in the most risk-associated monomethylated metabolite, methylarsonic acid, whereas changes between 1.6 and 5.3% of methylarsonic acid could be attributed to haplotypes of AS3MT and DNMT1a. CONCLUSION: Independent of the genotype, the efficiency of arsenic methylation increased markedly over the course of pregnancy. The effect of pregnancy on the metabolite pattern during the observational period was greater than the effect of genotype.
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| 3. |
- Ahmed, Sultan, et al.
(författare)
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Arsenic-Associated Oxidative stress, Inflammation, and Immune Disruption in Human Placenta and Cord Blood
- 2011
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Ingår i: Journal of Environmental Health Perspectives. - : Environmental Health Perspectives. - 0091-6765 .- 1552-9924. ; 119:2, s. 258-264
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Arsenic (As) exposure during pregnancy induces oxidative stress and increases the risk of fetal loss and low birth weight. OBJECTIVES: This study aimed to elucidate the effects of As exposure on immune markers in the placenta and cord blood, and the involvement of oxidative stress. METHODS: Pregnant women were enrolled around gestational week (GW) 8 in our longitudinal, population-based, mother-child cohort in Matlab, an area in rural Bangladesh with large variations in As concentrations in well water. Women (n=130) delivering at local clinics were included in the present study. We collected maternal urine twice during pregnancy (GW8 and 30) for measurements of As, and placenta and cord blood at delivery for assessment of immune and inflammatory markers. Placental markers were measured by immunohistochemistry and cord blood cytokines by multiplex cytokine assay. RESULTS: In multivariable adjusted models, maternal urinary As (U-As) exposure both at GW8 and 30 was significantly positively associated with placental markers of 8-oxoguanine (8-oxoG) and IL-1β, U-As at GW8 with TNF- α and IFN-γ, U-As at GW30 with leptin , and U-As at GW8 was inversely associated with CD3-T cells in the placenta. Cord blood cytokines (IL-1β, IL-8, IFN-γ, TNF-α) showed a U-shaped association with U-As at GW30. Placental 8-oxoG was significantly positively associated with placental pro-inflammatory cytokines. Multivariable adjusted analyses suggested that enhanced placental cytokine expression (TNF-α and IFN-γ) was primarily influenced by oxidative stress, while leptin expression appeared to be mostly mediated by As, and IL-1β appeared to be influenced by both oxidative stress and As. CONCLUSION: As exposure during pregnancy appeared to enhance placental inflammatory responses (in part by increasing oxidative stress), reduce placental T cells, and alter cord blood cytokines. These findings suggest that effects of As on immune function may contribute to impaired fetal and infant health.
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| 4. |
- Chen, Shuyun, et al.
(författare)
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Random capillary glucose levels throughout pregnancy, obstetric and neonatal outcomes, and long-term neurodevelopmental conditions in children : a group-based trajectory analysis.
- 2023
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Ingår i: BMC Medicine. - : BioMed Central (BMC). - 1741-7015. ; 21:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Gestational diabetes mellitus (GDM) is associated with both short- and long-term risks, although it is unknown if risks vary by severity, timing, and duration of gestational hyperglycemia. We aimed to identify trajectories of random capillary glucose (RCG) levels throughout pregnancy and assess their associations with both obstetric/neonatal outcomes and children's risk of neurodevelopmental conditions (NDCs) (i.e., autism, intellectual disability, and attention-deficit/hyperactivity disorders [ADHD]).METHODS: A population-based cohort study was conducted involving 76,228 children born to 68,768 mothers without pregestational diabetes. Group-based trajectory modeling was utilized to identify distinct glucose trajectories across RCG values throughout the course of pregnancy. The associations between these trajectory groups and obstetric/neonatal outcomes as well as children's NDCs were then assessed using generalized estimating equation models with a logit link. The Benjamini-Hochberg (BH) procedure was employed to adjust P-values for multiple comparisons, controlling the false discovery rate (FDR).RESULTS: Five distinct glucose trajectory groups were identified, each with varying percentages diagnosed with GDM. Their associations with obstetric/neonatal outcomes as well as children's NDCs varied. For example, when compared to the "Persistently Low" group, other groups exhibited varying degrees of increased risk for large-for-gestational-age babies, with the exception of the "High in Early Pregnancy" group. Compared to the "Persistently Low" group, all other trajectory groups were associated with NDC outcomes, except the "High in Mid-Pregnancy" group. However, none of the associations with offspring NDCs remained significant after accounting for the FDR correction.CONCLUSIONS: Persistent high glucose levels or moderately elevated glucose levels throughout pregnancy, as well as transient states of hyperglycemia in early or mid-pregnancy, were found to be associated with increased risks of specific obstetric and neonatal complications, and potentially offspring NDCs. These risks varied depending on the severity, timing, duration, and management of hyperglycemia. The findings underscore the need for continuous surveillance and individualized management strategies for women displaying different glucose trajectories during pregnancy. Limitations such as potential residual confounding, the role of mediators, and small sample size should be addressed in future studies.
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