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Prenatal manganese and cord blood mitochondrial DNA copy number: Effect modification by maternal anemic status.

ABSTRACT: INTRODUCTION:Manganese (Mn) is an essential nutrient but also a toxicant at high exposures, when it can induce oxidative stress (OS). Mn uptake is inversely correlated with iron status, therefore anemic individuals may be more susceptible to Mn overload induced-OS, which can manifest as changes in mitochondrial DNA copy number (mtDNA CN). Our objectives were to: 1) determine stage-specific associations of prenatal Mn exposure with cord blood MtDNA CN; and 2) investigate effect modification by maternal anemia, ferritin, and mean corpuscular volume (MCV). MATERIALS AND METHODS:We measured whole blood Mn, hemoglobin, serum ferritin, and MCV in the 2nd and 3rd trimester, in maternal blood at birth, and in cord blood from a prospective birth cohort in Mexico City, Mexico (n?=?485). We then extracted DNA from cord blood leukocytes to determine mtDNA CN. We used robust regression to measure associations between Mn and mtDNA CN at each trimester and at birth. Anemia (hemoglobin ?11?g/dL), iron deficiency (ferritin ?15?ng/mL) and MCV (stratified at median), were examined as effect modifiers. RESULTS:Mn levels increased throughout pregnancy, and Mn was inversely correlated with ferritin. We observed a positive association between Mn in the 3rd trimester and Mn in cord blood and mtDNA CN (??=?0.04-0.05; 95% CI?=?0.01, 0.08). Anemia significantly modified the association between mtDNA CN and Mn in the 2nd trimester. We found a positive association between 2nd trimester Mn and mtDNA CN in mothers with normal hemoglobin, and a negative association in those with low hemoglobin. (?high?=?0.06; 95% CI?=?0.01, 0.11; p?=?0.01 and ?low?=?-0.06; 95% CI?=?0.03, -0.13; p?=?0.06). No associations were detected between anemia, iron deficiency and MCV and mtDNA CN. CONCLUSIONS:Maternal blood Mn in the 3rd trimester and in cord blood was positively associated with mtDNA CN, suggesting that higher late pregnancy prenatal Mn exposures can impact newborn mitochondria by promoting OS. Furthermore, 2nd trimester Mn was positively associated with mtDNA in non-anemic mother-child pairs but inversely associated in anemic individuals, indicating potential interactions between Mn and chronic anemia.

SUBMITTER: Kupsco A

PROVIDER: S-EPMC6471611 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature

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Prenatal manganese and cord blood mitochondrial DNA copy number: Effect modification by maternal anemic status.

Kupsco Allison A Sanchez-Guerra Marco M Amarasiriwardena Chitra C Brennan Kasey J M KJM Estrada-Gutierrez Guadalupe G Svensson Katherine K Schnaas Lourdes L Pantic Ivan I Téllez-Rojo Martha María MM Baccarelli Andrea A AA Wright Robert O RO

Environment international 20190305

<h4>Introduction</h4>Manganese (Mn) is an essential nutrient but also a toxicant at high exposures, when it can induce oxidative stress (OS). Mn uptake is inversely correlated with iron status, therefore anemic individuals may be more susceptible to Mn overload induced-OS, which can manifest as changes in mitochondrial DNA copy number (mtDNA CN). Our objectives were to: 1) determine stage-specific associations of prenatal Mn exposure with cord blood MtDNA CN; and 2) investigate effect modificati ...[more]

PMID: 30849576

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Project description:BackgroundThe Supplementation with Multiple Micronutrients Intervention Trial (SUMMIT) in Lombok, Indonesia showed that maternal multiple micronutrients (MMN), as compared with iron and folic acid (IFA), reduced fetal loss, early infant mortality, and low birth weight. Mitochondria play a key role during pregnancy by providing maternal metabolic energy for fetal development, but the effects of maternal supplementation during pregnancy on mitochondria are not fully understood.ObjectiveThe aim of this study was to assess the impact of MMN supplementation on maternal mitochondrial DNA copy number (mtDNA-CN).MethodsWe used archived venous blood specimens from pregnant women enrolled in the SUMMIT study. SUMMIT was a cluster-randomized double-blind controlled trial in which midwives were randomly assigned to distribute MMN or IFA to pregnant women. In this study, we selected 108 sets of paired baseline and postsupplementation samples (MMN = 54 and IFA = 54). Maternal mtDNA-CN was determined by real-time quantitative polymerase chain reaction in baseline and postsupplementation specimens. The association between supplementation type and change in mtDNA-CN was performed using rank-based estimation for linear models.ResultsIn both groups, maternal mtDNA-CN at postsupplementation was significantly elevated compared with baseline (P < 0.001). The regression revealed that the MMN group had lower postsupplementation mtDNA-CN than the IFA group (β = -4.63, P = 0.003), especially for women with mtDNA-CN levels above the median at baseline (β = -7.49, P = 0.007). This effect was rapid, and observed within 33 d of initiation of supplementation (β = -7.39, P = 0.017).ConclusionMaternal MMN supplementation rapidly stabilized mtDNA-CN in pregnant women who participated in SUMMIT, indicating improved mitochondrial efficiency. The data provide a mechanistic basis for the beneficial effects of MMN on fetal growth and survival, and support the transition from routine IFA to MMN supplementation.This trial was registered at www.isrctn.com as ISRCTN34151616.

Project description:BACKGROUND:Prenatal ambient fine particulate matter (PM2.5) and maternal chronic psychosocial stress have independently been linked to changes in mithochondrial DNA copy number (mtDNAcn), a marker of mitochondrial response and dysfunction. Further, overlapping research shows sex-specific effects of PM2.5 and stress on developmental outcomes. Interactions among PM2.5, maternal stress, and child sex have not been examined in this context. METHODS:We examined associations among exposure to prenatal PM2.5, maternal lifetime traumatic stressors, and mtDNAcn at birth in a sociodemographically diverse pregnancy cohort (N=167). Mothers' daily exposure to PM2.5 over gestation was estimated using a satellite-based spatio-temporally resolved prediction model. Lifetime exposure to traumatic stressors was ascertained using the Life Stressor Checklist-Revised; exposure was categorized as high vs. low based on a median split. Quantitative real-time polymerase chain reaction (qPCR) was used to determine mtDNAcn in placenta and cord blood leukocytes. Bayesian Distributed Lag Interaction regression models (BDLIMs) were used to statistically model and visualize the PM2.5 timing-dependent pattern of associations with mtDNAcn and explore effect modification by maternal lifetime trauma and child sex. RESULTS:Increased PM2.5 exposure across pregnancy was associated with decreased mtDNAcn in cord blood (cumulative effect estimate=-0.78; 95%CI -1.41, -0.16). Higher maternal lifetime trauma was associated with reduced mtDNAcn in placenta (?=-0.33; 95%CI -0.63, -0.02). Among women reporting low trauma, increased PM2.5 exposure late in pregnancy (30-38weeks gestation) was significantly associated with decreased mtDNAcn in placenta; no significant association was found in the high trauma group. BDLIMs identified a significant 3-way interaction between PM2.5, maternal trauma, and child sex. Specifically, PM2.5 exposure between 25 and 40weeks gestation was significantly associated with increased placental mtDNAcn among boys of mothers reporting high trauma. In contrast, PM2.5 exposure in this same window was significantly associated with decreased placental mtDNAcn among girls of mothers reporting low trauma. Similar 3-way interactive effects were observed in cord blood. CONCLUSIONS:These results indicate that joint exposure to PM2.5 in late pregnancy and maternal lifetime trauma influence mtDNAcn at the maternal-fetal interface in a sex-specific manner. Additional studies will assist in understanding if the sex-specific patterns reflect distinct pathophysiological processes in addition to mitochondrial dysfunction.

Project description:Objective: To evaluate positive rate and accuracy of non-invasive prenatal testing (NIPT) combining Z-score and maternal copy number variation (CNV) analysis. To assess the relationship between Z-score and positive predictive value (PPV). Methods: This prospective study included 61525 pregnancies to determine the correlation between Z-scores and PPV in NIPT, and 3184 pregnancies to perform maternal CNVs analysis. Positive results of NIPT were verified by prenatal diagnosis and/or following-up after birth. Z-score grouping, logistic regression analysis, receiver operating characteristic (ROC) curves, and S-curve trends were applied to correlation analysis of Z-scores and PPV. The maternal CNVs were classified according to the technical standard for the interpretation of ACMG. Through genetic counseling, fetal and maternal phenotypes and family histories were collected. Results: Of the 3184 pregnant women, 22 pregnancies were positive for outlier Z-scores, suggesting fetal aneuploidy. 12 out of 22 pregnancies were true positive (PPV = 54.5%). 17 pregnancies were found maternal pathogenic or likely pathogenic CNVs (> 0.5 Mb) through maternal CNV analysis. Prenatal diagnosis revealed that 7 out of 11 fetuses carried the same CNVs as the mother. Considering the abnormal biochemical indicators during pregnancy and CNV-related clinical phenotypes after birth, two male fetuses without prenatal diagnosis were suspected to carry the maternally-derived CNVs. Further, we identified three CNV-related family histories with variable phenotypes. Statistical analysis of the 61525 pregnancies revealed that Z-scores of chromosomes 21 and 18 were significantly associated with PPV at 3 ≤ Z ≤ 40. Notably, three pregnancies with Z > 40 were both maternal full aneuploidy. At Z < -3, fetuses carried microdeletions instead of monosomies. Sex chromosome trisomy was significantly higher PPV than monosomy. Conclusion: The positive rate of the NIPT screening model combining Z-score and maternal CNV analysis increased from 6.91‰ (22/3184) to 12.25‰ (39/3184) and true positives increased from 12 to 21 pregnancies. We found that this method could improve the positive rate and accuracy of NIPT for aneuploidies and CNVs without increasing testing costs. It provides an early warning for the inheritance of pathogenic CNVs to the next generation.

Dataset Information

Prenatal manganese and cord blood mitochondrial DNA copy number: Effect modification by maternal anemic status.

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Prenatal manganese and cord blood mitochondrial DNA copy number: Effect modification by maternal anemic status.

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