Akifumi Eguchi

Chiba study of Mother and Children's Health (C-MACH): cohort study with omics analyses

Purpose Recent epidemiological studies have shown that environmental factors during the fetal period to early childhood might affect the risk of non-communicable diseases in adulthood. This is referred to as the developmental origins of health and disease (DOHaD) concept. The Chiba study of Mother and Childrens Health (C-MACH) is a birth cohort study based on the DOHaD hypothesis and involves multiomics analysis. This study aims to explore the effects of genetic and environmental factors—particularly the fetal environment and postbirth living environment—on childrens health, and to identify potential biomarkers for these effects. Participants The C-MACH consists of three hospital-based cohorts. The study participants are pregnant women at <13 weeks gestation. Women who underwent an examination in one of the three hospitals received an explanation of the study. The participants consented to completing questionnaire surveys and the collection and storage of biological and house/environmental samples. Participants were provided unique study numbers. All of the data and biological specimens will be stored in the Chiba University Center for Preventive Medical Sciences and Chiba University Center for Preventive Medical Sciences BioBank, respectively. Findings to date Consent to participate was obtained from 433 women. Of these women, 376 women completed questionnaires in the early gestational period. The mean age was 32.5 (4.4) years. The mean body mass index (BMI) was 21.1 (3.0) kg/m2. Before pregnancy, 72.3% of the women had a BMI of 18.5–24.9 kg/m2. During early pregnancy, 5.0% of the participants smoked. Future plans Primary outcomes are allergy, obesity, endocrine and metabolic disorders, and developmental disorders. Genome-level, metabolome-level, umbilical cord DNA methylation (epigenome), gut microbiota and environmental chemical exposure variables will be evaluated. We will analyse the relationships between the outcomes and analytical variables.

Exploration of potential biomarkers and related biological pathways for PCB exposure in maternal and cord serum: A pilot birth cohort study in Chiba, Japan

Polychlorinated biphenyls (PCBs) have been associated with adverse human reproductive and fetal developmental measures or outcomes because of their endocrine-disrupting effects; however, the biological mechanisms of adverse effects of PCB exposure in humans are not currently well established. In this study, we aimed to identify the biological pathways and potential biomarkers of PCB exposure in maternal and umbilical cord serum using a hydrophilic interaction chromatography-tandem mass spectrometry (HILIC-MS/MS) metabolomics platform. The median concentration of total PCBs in maternal (n=93) and cord serum (n=93) were 350 and 70pgg-1 wet wt, respectively. PCB levels in maternal and fetal serum from the Chiba Study of Mother and Childrens Health (C-MACH) cohort are comparable to those of earlier cohort studies conducted in Japan, the USA, and European countries. We used the random forest model with the metabolome profile to predict exposure levels of PCB (first quartile [Q1] and fourth quartile [Q4]) for pregnant women and fetuses. In the prediction model for classification of Q1 versus Q4 (area-under-curve [AUC]: pregnant women=0.812 and fetuses=0.919), citraconic acid level in maternal serum and ethanolamine, p-hydroxybenzoate, and purine levels in cord serum had >0.70 AUC values. These candidate biomarkers and metabolite included in composited models were related to glutathione and amino acid metabolism in maternal serum and the amino acid metabolism and ubiquinone and other terpenoid-quinone biosynthesis in cord serum (FDR <0.10), indicating disruption of metabolic pathways by PCB exposure in pregnant women and fetuses. These results showed that metabolome analysis might be useful to explore potential biomarkers and related biological pathways for PCB exposure. Thus, more detailed studies are needed to verify sensitivity of the biomarkers and clarify the biochemical changes resulting from PCB exposure.

Maternal–fetal transfer rates of PCBs, OCPs, PBDEs, and dioxin-like compounds predicted through quantitative structure–activity relationship modeling

The present study aims to predict the maternal–fetal transfer rates of the polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs), and dioxin-like compounds using a quantitative structure–activity relationship model. The relation between the maternal–fetal transfer rate and the contaminants’ physicochemical properties was investigated by multiple linear regression (MLR), partial least square regression (PLS), and random forest regression (RF). The 10-fold cross-validation technique estimated low predictive performances for both MLR and PLS models (R2CV = 0.425 ± 0.0964 for MLR and R2CV = 0.492 ± 0.115 for PLS) and is in agreement with an external test (R2pred = 0.129 for MLR and R2pred = 0.123 for PLS). In contrast, the RF model exhibits good predictive performance, estimated through 10-fold cross-validation (R2CV = 0.566 ± 0.0885) and an external test set (R2pred = 0.519). Molecular weight and polarity were selected in all models as important parameters that may predict the ability of a molecule to cross the placenta to the fetus.

The effects of early postnatal exposure to a low dose of decabromodiphenyl ether (BDE-209) on serum metabolites in male mice

The toxicity of decabromodiphenyl ether (BDE-209) has been reported in several studies. However, there is not much known about the toxicological biomarkers that characterize BDE-209 exposure. In this study, we subcutaneously exposed mice to 0.025 mg/kg/day BDE-209 on postnatal days 1‑5 and sacrificed the animals at 12 weeks of age (day 84). Flow injection analysis and hydrophilic interaction chromatography-triple quadrupole mass spectrometry were used to determine the serum metabolomes of these mice in order to characterize the effects of BDE-209 exposure. Data analysis showed a good separation between control and exposed mice (R(2) = 0.953, Q(2) = 0.728, and ANOVA of the cross‑validated residuals (CV‑ANOVA): P‑value = 0.0317) and 54 metabolites were identified as altered in the exposed animals. These were selected using variable importance (VIP) and loadings scaled by a correlation coefficient criteria and orthogonal partial least squares discriminant analysis (OPLS‑DA). BDE‑209‑exposed mice showed lower levels of long-chain acylcarnitines and citrate cycle-related metabolites, and higher levels of some amino acids, long-chain phospholipids, and short-chain acylcarnitines. The disruption of fatty acid, carbohydrate, and amino acid metabolism observed in the serum metabolome might be related to the previously observed impaired spermatogenesis in mice with early postnatal exposure to a low dose of BDE-209.

The methylation levels of the H19 differentially methylated region in human umbilical cords reflect newborn parameters and changes by maternal environmental factors during early pregnancy

Abstract H19 is a tumor‐suppressor gene, and changes in the methylation of the H19‐differential methylation region (H19‐DMR) are related to human health. However, little is known about the factors that regulate the methylation levels of H19‐DMR. Several recent studies have shown that maternal environmental factors during pregnancy, such as smoking, drinking, chemical exposure, and nutrient intake, can alter the methylation levels of several genes in fetal tissues. In this study, we examined the effects of maternal factors on changes in the methylation levels of H19‐DMR in the human umbilical cord (UC), an extra‐embryonic tissue. Participants from the Chiba study of Mother and Childrens Health (C‐MACH) were enrolled in this study. Genomic DNA was extracted from UC samples, and the methylation level of H19‐DMR was evaluated by methylation‐sensitive high resolution melting analysis. Individual maternal and paternal factors and clinical information for newborns at birth were examined using questionnaires prepared in the C‐MACH study, a brief‐type self‐administered diet history questionnaire (BDHQ) during early pregnancy (gestational age of 12 weeks), and medical records. Univariate and multivariate logistic regression analyses indicated that reduced H19‐DMR methylation (<50% methylation) in UC tissues was positively related to decreased head circumference in newborns [odds ratio (OR) =2.82; 95% confidence intervals (CI): 1.21–6.87; p=0.0183 and OR =2.51; 95% CI: 1.02–6.46; p=0.0499, respectively]. Moreover, multiple comparison test showed that H19‐DMR methylation in UC tissues was significantly reduced in the low calorie group (intake of less than 1,000 kcal/day; methylation level: 40.98%; 95% CI: 33.86–48.11) compared with that in the middle (1,000–1,999 kcal/day; methylation level: 51.28%; 95% CI: 48.28–54.27) and high (≥2,000 kcal/day; methylation level: 52.16%; 95% CI: 44.81–59.51) calorie groups (p=0.0054 and 0.047, respectively). In the subpopulations with low to moderate calorie intake (<2,000 kcal/day), reduced H19‐DMR methylation in UC tissues was significantly related to serum homocysteine concentration (OR =0.520; 95% CI: 0.285–0.875; p=0.019), maternal age (OR =1.22; 95% CI: 1.01–1.52; p=0.049), and serum folate levels (OR =0.917; 95% CI: 0.838–0.990; p=0.040). These data indicated that H19‐DMR methylation levels in human UC tissues could be modulated by maternal factors during early pregnancy and may affect fetal and newborn growth. HighlightsWe examined the effect of maternal factors on H19‐DMR methylation in umbilical cords (UC).Reduced H19‐DMR methylation in UCs was related to decreased head circumference.H19‐DMR methylation in UCs was reduced in the low calorie group.Decreased serum folate levels were associated with lower H19‐DMR methylation in UCs.H19‐DMR methylation in UCs could be modulated by maternal factors during pregnancy.

Accelerated oligosaccharide absorption and altered serum metabolites during oral glucose tolerance test in young Japanese with impaired glucose tolerance

Impaired glucose tolerance (IGT) is a subtype of prediabetes, a condition having high risk for development to diabetes mellitus, but its pathophysiology is not fully understood. In the present study, we examined metabolic changes in IGT by using two types (D‐glucose [Glc] and partial hydrolysate of starch [PHS]) of oral glucose tolerance tests (OGTTs), with emphasis on serum incretins and metabolites.

Alterations in urinary metabolomic profiles due to lead exposure from a lead–acid battery recycling site

Lead poisoning is considered a public health threat, particularly in developing countries. Health problems from Pb exposure occur in many parts of the world, especially near Pb mines, Pb smelters, and used lead-acid battery (ULAB) recycling plants. In this study, we analyzed the urine metabolome of residents in a village located near a ULAB recycling facility to investigate the biological effects of Pb exposure (ULAB: n = 44, Reference: n = 51). Lasso linear regression models were moderately predictive of blood Pb levels, as evaluated by a training set (R2 = 0.813) and against an external test set (R2EXT = 0.647). In lasso logistic regression models, areas under receiver operating characteristic curves, as measured by 5-fold cross-validation (AUCCV = 0.871) and against an external test set (AUCEXT = 0.917), indicated accurate classification of urine samples from the affected village and from a reference site. Ten candidate biomarkers identified at false discovery rates of <0.05 were associated with ATP-binding cassette (ABC) transporters, possibly related to the disruption of small-molecule transport in the kidney; amino acid, porphyrin, and chlorophyll metabolism; and the heme biosynthetic pathway. Collectively, the results suggest that lead Pb is related to the health effects in individuals residing in ULAB site by alteration of these biological pathways.

Hsa-mir-144-3p is increased in umbilical cord serum of infants developing atopic dermatitis

Elevated hsa-miR-144-3p levels in umbilical cord serum may lower the threshold for allergen-induced skin inflammation. This gives insight in to possible mechanisms promoting early life atopic dermatitis and highlights the importance of skin barrier protection.

Exploration of predictive metabolic factors for gestational diabetes mellitus in Japanese women using metabolomic analysis

We aimed to explore novel predictive markers for gestational diabetes mellitus using metabolomic analysis in pregnant Japanese women.

Fetal exposure markers of dioxins and dioxin-like PCBs

Fetal exposure to polychlorinated biphenyls (PCBs), polychlorinated-p-dibenzodioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) have been associated with a number of adverse health outcomes. Although the placenta acts as a barrier between the mother and the fetus, these contaminants transfer through the placenta exposing the fetus. Several studies have investigated placental transfer, but few have assessed the co-variation among these contaminants. Maternal blood, cord blood, and cord tissue were collected from 41 Japanese mother-infant pairs and analyzed for dioxin-like PCBs and PCDD/Fs. Hierarchical cluster analysis followed by principal component analysis were used to assess the co-variation. Two stable clusters of dioxin-like PCBs were found in maternal and cord blood. One cluster of low/medium chlorinated dioxin-like PCBs was present in all three matrices with 2,3’,4,4’,5-PeCB(#118) and 3,3’,4,4’,5-PeCB(#126) explaining the majority of the clusters’ variances. Medium/high chlorinated dioxin-like PCBs clustered in maternal blood and cord blood but not in cord tissue. 2,3,4,4’,5-PeCB(#114) and 2,3,3’,4,4’,5,5’-HpCB(#189) explained the majority of the clusters’ variances. There was a substantial correlation between the sum of dioxin-like PCBs and total PCDD/F in all three matrices. The sum of the four suggested PCBs plus 3,3’,4,4’-TeCB(#77) correlated well with total PCDD/F in all three matrices. Apart from the dioxin-like PCBs, little co-variation existed among the studied contaminants. The five PCBs can be used as fetal exposure markers for dioxin and dioxin-like PCBs in maternal and cord blood respectively. In cord tissue, more higher chlorinated dioxin-like PCBs need to be measured as well.