Trimester-specific prenatal heavy metal exposures and sex-specific postpartum size and growth

Associations of occupational exposure to micro-LiNiCoMnO2 particles with systemic inflammation and cardiac dysfunction in cathode material production for lithium batteries

Micro-LiNiCoMnO2 (MNCM), a cathode material with highest market share, has increasing demand with the growth of lithium battery industry. However, whether MNCM exposure brings adverse effects to workers remains unclear. This study aimed to explore the association between MNCM exposure with systemic inflammation and cardiac function. A cross-sectional study of 347 workers was undertaken from the MNCM production industry in Guangdong province, China in 2020. Metals in urine were measured using ICP-MS. The associations between metals, systemic inflammation, and cardiac function were appraised using a linear or logistic regression model. Bayesian kernel machine regression (BKMR) and generalized weighted quantile sum (gWQS) models were used to explore mixed metal exposures. The analysis of interaction and mediation was adopted to assess the role of inflammation in the relation between urinary metals and cardiac function. We observed that the levels of lithium (Li) and cobalt (Co) were positively associated with systemic inflammation and heart rate. The amount of Co contributed the highest weight on the increased systemic immune-inflammation index (SII) (59.8%), the system inflammation response index (SIRI) (44.3%), and heart rate (65.0%). Based on the mediation analysis, we estimated that SII mediated 32.3% and 20.9% of the associations between Li and Co with heart rate, and SIRI mediated 44.6% and 22.2% of the associations between Li and Co with heart rate, respectively. This study demonstrated for the first time that MNCM exposure increased the risk of workers' systemic inflammation and elevated heart rate, which were contributed by the excessive Li and Co exposure. Additionally, it indicates that systemic inflammation was a major mediator of the associations of Li and Co with cardiac function in MNCM production workers.

Effects of exposure to multiple metallic elements in the first trimester of pregnancy on the risk of preterm birth

Exposure to certain heavy metals has been demonstrated to be associated with a higher risk of preterm birth (PTB). However, studies focused on the effects of other metal mixtures were limited. A nested case‒control study enrolling 94 PTB cases and 282 controls was conducted. Metallic elements were detected in maternal plasma collected in the first trimester using inductively coupled plasma‒mass spectrometry. The effect of maternal exposure on the risk of PTB was investigated using logistic regression, least absolute shrinkage and selection operator, restricted cubic spline (RCS), quantile g computation (QGC) and Bayesian kernel machine regression (BKMR). Vanadium (V) and arsenic (As) were positively associated with PTB risk in the logistic model, and V remains positively associated in the multi-exposure logistic model. QGC analysis determined V (69.42%) and nickel (Ni) (70.30%) as the maximum positive and negative contributors to the PTB risk, respectively. BKMR models further demonstrated a positive relationship between the exposure levels of the mixtures and PTB risk, and V was identified as the most important independent variable among the elements. RCS analysis showed an inverted U-shape effect of V and gestational age, and plasma V more than 2.18 μg/L was considered a risk factor for shortened gestation length. Exposure to metallic elements mixtures consisting of V, As, cobalt, Ni, chromium and manganese in the first trimester was associated with an increased risk of PTB, and V was considered the most important factor in the mixtures in promoting the incidence of PTB.

Associations between prenatal metal exposure and growth rate in children: Based on Hangzhou Birth Cohort Study

BACKGROUND

It has been reported that prenatal metal exposure is associated with child anthropometry. However, studies focusing on the growth rate of anthropometry among children have not been conducted. This study aimed to examine associations between the exposure of multiple metals during pregnancy and the growth rate of anthropometry among offspring.

METHODS

743 mother-child pairs from the Hangzhou Birth Cohort Study (HBCS) were included. Levels of eleven metals in mother's blood during pregnancy were measured. Offspring had a mean of 5.7 measurements on anthropometric indicators including weight, length/height, head circumference, and body mass index (BMI) within 1.5 years of birth. Generalized estimating equation (GEE) model was used to investigate the associations between maternal metal exposure and growth rate of anthropometric indicators in children. Stratification analysis by sex was also examined.

RESULTS

Levels of selenium (Se, β = 0.213, 95 % CI = 0.017 to 0.409, P = 0.033) were positively associated with length/height gain per month in children. Levels of chromium (Cr, β = 0.025, 95 % CI = 0.018 to 0.033, P < 0.001) were positively associated with the rate of weight gain. Levels of manganese (Mn, β = -0.030, 95 % CI = -0.052 to -0.008, P = 0.009) and cobalt (Co, β = -0.012, 95 % CI = -0.024 to -0.000, P = 0.044) were inversely associated with growth rate of head circumference. Children with higher maternal Mn levels had a lower BMI change rate. Associations between metals and growth rate were stronger in girls than in boys. Besides, significant associations between metal mixtures and growth rate were found.

CONCLUSION

Prenatal exposure to Se, Cr, Mn, and Co was associated with growth rate in children, with sex-specific disparities. Our results suggested important effects of maternal exposure to multiple metals on development in offspring.

Species- and subspecies-level characterization of health-associated bacterial consortia that colonize the human gut during infancy

BACKGROUND

The human gut microbiome develops rapidly during infancy, a key window of development coinciding with the maturation of the adaptive immune system. However, little is known about the microbiome growth dynamics over the first few months of life and whether there are any generalizable patterns across human populations. We performed metagenomic sequencing on stool samples (n = 94) from a cohort of infants (n = 15) at monthly intervals in the first 6 months of life, augmenting our dataset with seven published studies for a total of 4,441 metagenomes from 1,162 infants.

RESULTS

Strain-level de novo analysis was used to identify 592 of the most abundant organisms in the infant gut microbiome. Previously unrecognized consortia were identified which exhibited highly correlated abundances across samples and were composed of diverse species spanning multiple genera. Analysis of a published cohort of infants with cystic fibrosis identified one such novel consortium of diverse Enterobacterales which was positively correlated with weight gain. While all studies showed an increased community stability during the first year of life, microbial dynamics varied widely in the first few months of life, both by study and by individual.

CONCLUSION

By augmenting published metagenomic datasets with data from a newly established cohort, we were able to identify novel groups of organisms that are correlated with measures of robust human development. We hypothesize that the presence of these groups may impact human health in aggregate in ways that individual species may not in isolation.

Strain-level characterization of health-associated bacterial consortia that colonize the human gut during infancy

Background

The human gut microbiome develops rapidly during infancy, a key window of development coinciding with maturation of the adaptive immune system. However, little is known of the microbiome growth dynamics over the first few months of life and whether there are any generalizable patterns across human populations. We performed metagenomic sequencing on stool samples (n=94) from a cohort of infants (n=15) at monthly intervals in the first six months of life, augmenting our dataset with seven published studies for a total of 4,441 metagenomes from 1,162 infants.

Results

Strain-level de novo analysis was used to identify 592 of the most abundant organisms in the infant gut microbiome. Previously unrecognized consortia were identified which exhibited highly correlated abundances across samples and were composed of diverse species spanning multiple genera. Analysis of a cohort of infants with cystic fibrosis identified one such novel consortium of diverse Enterobacterales which was positively correlated with weight gain. While all studies showed an increased community stability during the first year of life, microbial dynamics varied widely in the first few months of life, both by study and by individual.

Conclusion

By augmenting published metagenomic datasets with data from a newly established cohort we were able to identify novel groups of organisms that are correlated with measures of robust human development. We hypothesize that the presence of these groups may impact human health in aggregate in ways that individual species may not in isolation.

Amniotic fluid rubidium concentration association with newborn birthweight: a maternal-neonatal pilot study

BACKGROUND

Although most biological systems, including human tissues, contain rubidium, its biogeochemical functions and possible role in neonatal birthweight are largely unknown. An animal study indicated a correlation between rubidium deficiency in the maternal diet and lower newborn birthweight.

OBJECTIVE

This pilot study measured rubidium concentrations in amniotic fluid during the second trimester of (low-risk) pregnancy and investigated potential correlations between rubidium levels and third-trimester newborn birthweight-small for gestational age, appropriate for gestational age, and large for gestational age-and between preterm birth and term birth in uncomplicated pregnancies.

STUDY DESIGN

This prospective, single-center study investigated a possible relationship between rubidium concentration in second-trimester amniotic fluid and third-trimester birthweight percentile. Amniotic fluid (at a median gestational age of 19 weeks) was sampled to determine rubidium concentration. Maternal and newborn characteristics were obtained from participant and delivery records.

RESULTS

After screening 173 pregnant women, 99 amniotic fluid samples were evaluated. Midpregnancy median rubidium concentrations were significantly lower among newborns that were classified as small for gestational age than among newborns that were classified as appropriate for gestational age (106 vs 136 μg/L; P<.01). Based on a logistic regression random forest model, amniotic fluid rubidium was identified as a significant contributing factor to appropriate-for-gestational-age birthweight with 54% of the total contribution.

CONCLUSION

Amniotic fluid rubidium concentration seems to be a strong predictor of appropriate-for-gestational-age birthweight and a potential marker for newborn birthweight classifications. In particular, low rubidium concentrations in amniotic fluid during midpregnancy are linked to third-trimester lower birthweight percentile. These findings could potentially serve as a valuable tool for early identification of pregnancy outcomes. Further investigation is necessary to fully explore the effect of rubidium on fetal development.

Pregnancy and lactation mixed exposure to lead, cadmium, and mercury alters maternal-offspring single heavy metal load: A factorial design

Environmental exposure to heavy metal mixture of lead (Pb), cadmium (Cd), and mercury (Hg) would induce hazardous health effects. However, there is a paucity of data on how exposure to heavy metal mixture alters the metabolic dynamics of individual metals. Considering that the dose plays a key role in determining the toxicity of heavy metals, we performed a factorial design with three heavy metals (Pb, Cd, and Hg) at low exposure levels. Female rats were exposed to Pb, Cd, and (or) Hg from successful mating until pup weaning. Their concentrations in maternal blood, breast milk, and postnatal day 0 (PND0) and PND21 offspring blood and whole brain were measured. Using ANOVA analysis, Pearson correlation, and structural equation model, we demonstrated the complex interactions among heavy metals during their absorption, mother-offspring transport, and target organ accumulation. Among all the explored samples, almost all the highest Pb, Cd, and Hg levels were observed in their respective single heavy metal exposure groups. In addition, Hg was found could antagonize the transport of Pb or Cd, when they cross the placental barrier and blood-brain barriers (BBB). However, the effect of Hg no longer presented when they are absorbed through the digestive system. The antagonistic effect of Pb on Cd was observed when they cross the placental barrier. In addition, Cd was also found to compete the transport pathway of Pb when they cross the BBB after birth. Compared to Pb and Hg, we found that the transport efficiency of Cd in the digestive system was lower, whereas the chelation of Cd by the placental barrier was better. This preliminary information may help researchers to explore the mechanism underlying the hazardous effects of heavy metal mixture exposure, or for regulatory agencies to revise guidelines for heavy metal exposure.