Prenatal cadmium exposure is associated with shorter leukocyte telomere length in Chinese newborns

Early life exposure to mercury and relationships with telomere length and mitochondrial DNA content in European children

BACKGROUND

Telomere length (TL) and mitochondrial function expressed as mitochondrial DNA copy number (mtDNAcn) are biomarkers of aging and oxidative stress and inflammation, respectively. Methylmercury (MeHg), a common pollutant in fish, induces oxidative stress. We hypothesized that elevated oxidative stress from exposure to MeHg decreases mtDNAcn and shortens TL.

METHODS

Study participants are 6-11-year-old children from the HELIX multi-center birth cohort study, comprising six European countries. Prenatal and postnatal total mercury (THg) concentrations were measured in blood samples, TL and mtDNAcn were determined in child DNA. Covariates and confounders were obtained by questionnaires. Robust regression models were run, considering sociodemographic and lifestyle covariates, as well as fish consumption. Sex, ethnicity, and fish consumption interaction models were also run.

RESULTS

We found longer TL with higher pre- and postnatal THg blood concentrations, even at low-level THg exposure according to the RfD proposed by the US EPA. The prenatal association showed a significant linear relationship with a 3.46 % increase in TL for each unit increased THg. The postnatal association followed an inverted U-shaped marginal non-linear relationship with 1.38 % an increase in TL for each unit increased THg until reaching a cut-point at 0.96 μg/L blood THg, from which TL attrition was observed. Higher pre- and postnatal blood THg concentrations were consistently related to longer TL among cohorts and no modification effect of fish consumption nor children's sex was observed. No association between THg exposure and mtDNAcn was found.

DISCUSSION

We found evidence that THg is associated with TL but the associations seem to be time- and concentration-dependent. Further studies are needed to clarify the mechanism behind the telomere changes of THg and related health effects.

Exposure to pollution during the first thousand days and telomere length regulation: A literature review

Telomere length (TL) is a biomarker for cellular senescence and TL erosion is predictive of the risk for age-related diseases. Despite being genetically determined at birth, TL may be susceptible to modifications through epigenetic mechanisms. Pollutant agents are considered one of the major threats to both human and planetary health. Their ability to cross the placental barrier and induce oxidative stress in fetal cells is particularly concerning and it may be associated with early TL erosion. In consideration of the timely relevance of this topic, we conducted a literature review on the impact of prenatal exposure to pollutant agents on newborn TL. The search yielded a total of 1099 records, of which only 32 met the inclusion criteria for the review. These criteria included the participation of human subjects, a longitudinal design or collection of longitudinal data, reporting of original TL data, and a focus on exposure to pollutant agents. The majority of the studies reported a significant inverse association between prenatal exposure to pollutant agents and TL. Furthermore, the second trimester of pregnancy emerged as a special sensitive period for the occurrence of pollutant agent-driven TL modifications. Sex differences were inconsistently reported across studies. This review contributes to highlighting biochemical pathways for the threats of environmental pollution to human health. Future research is warranted to further highlight potential buffering mechanisms.

Associations between maternal serum neonicotinoid pesticide exposure during pregnancy and newborn telomere length: Effect modification by sampling season

BACKGROUND

An increasing amount of evidence suggests that telomere length (TL) at birth can predict lifespan and is associated with chronic diseases later in life, but newborn TL may be affected by environmental pollutants. Neonicotinoids (NEOs) are widely used worldwide, and despite an increasing number of studies showing that they may have adverse effects on birth in mammals and even humans, few studies have examined the effect of NEO exposure on newborn TLs.

OBJECTIVE

To investigate the effects of prenatal exposure to NEOs and the interactions between NEOs and sampling season on newborn TL.

METHODS

We conducted a prospective cohort study of 500 mother-newborn pairs from the Guangxi Zhuang Birth Cohort. Ultraperformance liquid chromatographymass spectrometry was used to detect ten NEOs in maternal serum, and fluorescence quantitative PCR was used to estimate the newborn TL. A generalized linear model (GLM) was used to evaluate the relationships between individual NEO exposures and TLs , and quantile g-computation (Qgcomp) model and Bayesian kernel machine regression (BKMR) model were used to evaluate the combined effect of mixtures of components.

RESULTS

The results of the GLM showed that compared with maternal TMX levels < LOD, maternal TMX levels < median were negatively correlated with newborn TL (-6.93%, 95% CI%: -11.92%, -1.66%), and the decrease in newborn TL was more pronounced in girls (-9.60%, 95% CI: -16.84%, -1.72%). Moreover, different kinds of maternal NEO exposure had different effects on newborn TL in different sampling seasons, and the effect was statistically significant in all seasons except in autumn. Mixed exposure analysis revealed a potential positive trend between NEOs and newborn TL, but the association was not statistically significant.

CONCLUSION

Prenatal exposure to TMX may shorten newborn TL, and this effect is more pronounced among female newborns. Furthermore, the relationship between NEO exposure and TL may be modified by the sampling season.

Prenatal exposure to environmental heavy metals and newborn telomere length: A systematic review and meta-analysis

Exposure to environmental heavy metals is associated with telomere length (TL) alteration. Available information regarding the effect of prenatal exposure to environmental pollutants on newborn TL is controversial. The aim of this study is to systematically review and conduct a meta-analysis of the existing epidemiological studies on the associations between prenatal metal exposure and newborn TL. A comprehensive literature search was performed using the online databases of PubMed, Web of Science, and ScienceDirect from their inception to December 1, 2023. Thirteen eligible studies were included from the overall initial identification of 3559 records. The effect size was expressed as standardized beta coefficients with 95% confidence intervals (CIs) by the restricted maximum-likelihood approach with a weighted random-effects model. Prenatal exposure to environmental heavy metals was associated with a shorter newborn TL (standardized beta = -0.04; 95% CI: -0.08, 0.00; p = 0.05). Subgroup analysis showed that prenatal exposure to cadmium was significantly, negatively associated with TL in newborns (standardized beta = -0.05; 95% CI: -0.10, -0.01; p = 0.021). Heavy metal exposure during the third trimester was significantly associated with a shorter TL in newborns (standardized beta = -0.05; 95% CI: -0.11, -0.01; p = 0.045). No significant association was found between the newborn's sex and exposure sample type. This study provides evidence for the negative effect of prenatal exposure to heavy metals on newborn TL. In particular, cadmium exposure and exposure during the third trimester of pregnancy are critical factors associated with heavy metal-induced TL shortening.

Associations of self-reported sleep duration and sleep quality during pregnancy with newborn telomere length

BACKGROUND

Telomere length (TL) at birth is considered a potential biomarker for lifelong health. Although maternal sleep disturbance has been linked to a series of adverse pregnancy outcomes, evidence on the effect of maternal sleep on newborn TL remains scarce. Therefore, we aim to investigate the association of maternal sleep duration and sleep quality with newborn TL.

METHODS

A total of 742 mother-newborn pairs were recruited from Wuhan Children's Hospital between November 2013 and March 2015. Cord blood TL was measured using real-time quantitative polymerase chain reaction. Maternal sleep duration and quality during late pregnancy were obtained via questionnaires. Multivariate linear regression models were used to estimate the effects of maternal sleep duration and sleep quality on newborn TL.

RESULTS

A total of 742 maternal-newborn pairs were included in the analyses. Mothers sleeping ≥10 hours had a 9.30% (95% CI: 2.09%, 15.99%) shorter newborn TL than those sleeping 7-<9 hours. However, the association in mothers with short sleep duration (<7 hours) did not reach statistical significance. Compared to mothers with good sleep quality, those with poor sleep quality had a 9.91% (95% CI: 4.06%, 15.40%) shorter newborn TL. We observed a joint effect of sleep duration and sleep quality on newborn telomere shortening. Women with sleep duration ≥10 hours and poor sleep quality were most likely to have newborns with short TL (percent change:-19.66%, 95% CI: -28.42, -9.84%).

CONCLUSIONS

Long sleep duration and poor sleep quality during late pregnancy were associated with shorter newborn TL.

Early Environment and Telomeres: a Long-Term Toxic Relationship

PURPOSE OF REVIEW

Telomere length (TL) shortening is a hallmark of biological aging. While studies have extensively focused on the impact of environmental exposures on TL in older populations, consistent evidence indicates that prenatal environmental exposures to air pollutants, polycyclic aromatic hydrocarbons, metals, and endocrine-disrupting chemicals influence TL shortening. Here, we summarize evidence linking prenatal environmental exposures with children's TL and discuss potential long-term effects.

RECENT FINDINGS

Current evidence shows that prenatal environmental exposures alter TL and identify pregnancy as a critical window of susceptibility for telomere damage in children. However, results vary across studies, possibly depending on the source, exposure time window, and stage evaluated. Additional research is needed to investigate whether early TL alterations mediate long-term health effects of offspring. Prenatal environmental exposures induce early childhood changes in TL. Based on known links between TL and biological aging, these alterations may have long-term impact on individuals' health throughout life.

Prenatal Exposure to Potentially Toxic Metals and Their Effects on Genetic Material in Offspring: a Systematic Review

In recent years, the background level of environmental pollutants, including metals, has increased. Pollutant exposure during the earliest stages of life may determine chronic disease susceptibility in adulthood because of genetic or epigenetic changes. The objective of this review was to identify the association between prenatal and early postnatal exposure to potentially toxic metals (PTMs) and their adverse effects on the genetic material of offspring. A systematic review was carried out following the Cochrane methodology in four databases: PubMed, Scopus, Web of Science, and the Cochrane Library. Eligible papers were those conducted in humans and published in English between 2010/01/01 and 2021/04/30. A total of 57 articles were included, most of which evaluated prenatal exposure. Most commonly evaluated PTMs were As, Cd, and Pb. Main adverse effects on the genetic material of newborns associated with PTM prenatal exposure were alterations in telomere length, gene or protein expression, mitochondrial DNA content, metabolomics, DNA damage, and epigenetic modifications. Many of these effects were sex-specific, being predominant in boys. One article reported a synergistic interaction between As and Hg, and two articles observed antagonistic interactions between PTMs and essential metals, such as Cu, Se, and Zn. The findings in this review highlight that the problem of PTM exposure persists, affecting the most susceptible populations, such as newborns. Some of these associations were observed at low concentrations of PTMs. Most of the studies have focused on single exposures; however, three interactions between essential and nonessential metals were observed, highlighting that metal mixtures need more attention.

Association between rare earth element exposure during pregnancy and newborn telomere length

Telomere length (TL) is considered a marker of biological aging and lifetime health, and some epidemiological studies report that the environmental exposures may influence TL at birth. We aimed to investigate the associations between prenatal rare earth elements (REE) exposure and newborn TL. A total of 587 mother-newborn pairs were recruited during 2013 to 2015 in Wuhan, China. Maternal urinary concentrations of REE collected during three trimesters were measured by inductively coupled plasma mass spectrometry. Quantitative real-time polymerase chain reaction was used to measure relative cord blood TL. The trimester-specific associations between prenatal REE exposure and cord blood TL were evaluated using multiple informant models. Weighted quantile sum regression was used to estimate the mixture effect of urinary REE on cord blood TL. After adjustment for potential confounders, per doubling of urinary REE (Dy, Yb, Pr, Nd, and Tm) concentrations (μg/g creatinine) during the second trimester was respectively associated with 1.94% (95% CI 0.19%, 3.72%), 2.10% (95% CI 0.31%, 3.92%), 2.11% (95% CI 0.35%, 3.89%), 2.08% (95% CI 0.01%, 4.20%), and 1.38% (95% CI 0.09%, 2.70%) increase in cord blood TL. Furthermore, exposure to the mixture of REE during the second trimester was also significantly associated with increased cord blood TL (percent change 1.20%, 95% CI 0.30%, 2.11%). However, these associations were not statistically significant in the first and third trimesters. This study provides new evidence on the potential effect of prenatal REE exposure on the initial (newborn) setting of offspring's telomere biology. Further epidemiological studies are warranted to confirm our findings.

Does maternal low-dose cadmium exposure increase the risk of offspring to develop metabolic syndrome and/or type 2 diabetes?

Cadmium is a hazardous metal with multiple organ toxicity that causes great harm to human health. Cadmium enters the human body through occupational exposure, diet, drinking water, breathing, and smoking. Cadmium accumulation in the human body is associated with increased risk of developing obesity, cardiovascular disease, diabetes, and metabolic syndrome (MetS). Cadmium uptake is enhanced during pregnancy and can cross the placenta affecting placental development and function. Subsequently, cadmium can pass to fetus, gathering in multiple organs such as the liver and pancreas. Early-life cadmium exposure can induce hepatic oxidative stress and pancreatic β-cell dysfunction, resulting in insulin resistance and glucose metabolic dyshomeostasis in the offspring. Prenatal exposure to cadmium is also associated with increasing epigenetic effects on the offspring's multi-organ functions. However, whether and how maternal exposure to low-dose cadmium impacts the risks of developing type 2 diabetes (T2D) in the young and/or adult offspring remains unclear. This review collected available data to address the current evidence for the potential role of cadmium exposure, leading to insulin resistance and the development of T2D in offspring. However, this review reveals that underlying mechanisms linking prenatal cadmium exposure during pregnancy with T2D in offspring remain to be adequately investigated.

Effects of prenatal exposure to bisphenols on newborn leucocyte telomere length: a prospective birth cohort study in China

Telomere length (TL) at birth is related to diseases that may arise in the future and long-term health. Bisphenols exhibit toxic effects and can cross the placenta barrier. However, the effects of prenatal exposure to bisphenols on newborn TL remain unknown. We aimed to explore the effects of prenatal exposure to bisphenols (i.e., bisphenol A [BPA], bisphenol B [BPB], bisphenol F [BPF], bisphenol S [BPS] and tetrabromobisphenol A [TBBPA]) on relative TL in newborns. A total of 801 mother-infant pairs were extracted from the Guangxi Zhuang Birth Cohort. The relationship between bisphenol levels in maternal serum and relative TL in cord blood was examined by generalized linear models and restricted cubic spline (RCS) models. After adjusting for confounders, we observed a 3.19% (95% CI: -6.08%, -0.21%; P = 0.037) reduction in relative cord blood TL among mothers ≥ 28 years old, with each onefold increase in BPS. However, in each onefold increase of TBBPA, we observed a 3.31% (95% CI: 0.67%, 6.01%; P = 0.014) increase in relative cord blood TL among mothers < 28 years old. The adjusted RCS models revealed similar results (P overall < 0.05, P non-linear > 0.05). This study was the first to establish a positive association between serum TBBPA levels and relative TL in newborns born to young mothers. However, BPS levels were inversely correlated with TL in fetus born to old mothers. The results suggested that the fetus of old pregnant women may be more sensitive to BPS exposure. Moreover, BPS exposure early in life may accelerate aging or increase the risk of developing BPS-related diseases in later life.

Associations between prenatal multiple plasma metal exposure and newborn telomere length: Effect modification by maternal age and infant sex

Exposure to metals during pregnancy may affect maternal and infant health. However, studies on the combined effects of metals on the telomere length (TL) of newborns are limited. A prospective cohort study was conducted among 1313 mother-newborn pairs in the Guangxi Zhuang Birth Cohort. The concentrations of metals in maternal plasma during the first trimester were measured using inductively coupled plasma-mass spectrometry. We explored the associations between nine plasma metals and newborn TL using generalized linear models (GLMs), principal component analysis (PCA), quantile g-computation (qgcomp), and Bayesian kernel machine regression (BKMR). The GLMs revealed the inverse association between plasma arsenic (percent change, -5.56%; 95% CI: -7.69%, -3.38%) and barium concentrations (-9.84%; 95% CI: -13.81%, -5.68%) and newborn TL. Lead levels were related to significant decreases in newborn TL only in females. The PCA revealed a negative association between the PC3 and newborn TL (-4.52%; 95% CI: -6.34%, -2.68%). In the BKMR, the joint effect of metals was negatively associated with newborn TL. Qgcomp indicated that each one-tertile increase in metal mixture levels was associated with shorter newborn TL (-9.39%; 95% CI: -14.32%, -4.18%). The single and joint effects of multiple metals were more pronounced among pregnant women carrying female fetuses and among pregnant women <28 years of age. The finding suggests that prenatal exposure to arsenic, barium, antimony, and lead and mixed metals may shorten newborn TLs. The relationship between metal exposures and newborn TL may exhibit heterogeneities according to infant sex and maternal age.

Sirtuin-1 attenuates cadmium-induced renal cell senescence through p53 deacetylation

Cadmium (Cd), the common environmental pollutant, primarily targets at renal proximal tubules and induces nephrotoxicity. Cellular senescence, a phenomenon of cell growth arrest and a characteristics of maladaptive cell self-repair, is associated with renal disease progression. However, whether and how Cd induces renal tubular cells premature senescence is unknown. In our study, we found that Cd induced kidney damage and dysfunctions, which correlated with exacerbated tubular cell senescence, evidenced by increased senescence-associated β-galactosidase activity, the upregulated protein expression of p53 and p21^Waf1/Cip1 proteins, and elevated expression and secretion of cytokines in human proximal tubular epithelial HK-2 cells in vitro and in Cd-treated mice in vivo. Moreover, a S-phase arrest and decrease in Edu positive rate were found in Cd-treated HK-2 cells. Mechanistically, Cd suppressed the expression and activity of Sirtuin-1 (SIRT1), an anti-senescence deacetylase, resulting in the accumulation of acetylated p53 and upregulation of p21^Waf1/Cip1. Activation of SIRT1 significantly abolished Cd-induced premature senescence and S-phase arrest. Finally, silencing p21^Waf1/Cip1 efficiently delayed premature senescence and recovered cell cycle progression. These findings indicate that Cd promotes tubular cells senescence and impairs tubular cells regeneration, resulting in kidney dysfunctions, which could be ameliorated by SIRT1 activation.

Urinary cadmium and peripheral blood telomere length predict the risk of renal function impairment: a study of 547 community residents of Shanxi, China

Few reports have investigated the predictive value of urinary cadmium (UCd) and telomere length on renal function impairment. Therefore, we constructed nomogram models, using a cross-sectional survey to analyze the potential function of UCd and telomere length in renal function impairment risk. We randomly selected two community populations in Shanxi, China, and general information of the subjects was collected through face-to-face questionnaire surveys. Venous blood of subjects was collected to detect absolute telomere length (ATL) by real-time quantitative chain reaction (RT-PCR). Collecting urinary samples detected UCd and urinary N-acetyl-β-d-glucosaminidase (UNAG). Estimated glomerular filtration rate (eGFR) was obtained based on serum creatinine (SCr). Nomogram models on risk prediction analysis of renal function impairment was constructed. After adjusting for other confounding factors, UCd (β = 0.853, 95% confidence interval (CI): 0.739 ~ 0.986) and ATL (β = 1.803, 95%CI: 1.017 ~ 1.154) were independent risk influencing factors for increased UNAG levels, and the risk factors for eGFR reduction were UCd (β = 1.011, 95%CI: 1.187 ~ 1.471), age (β = 1.630, 95%CI: 1.303 ~ 2.038), and sex (β = 0.181, 95%CI: 0.105 ~ 0.310). Using UCd, ATL, sex, and age to construct the nomogram, and the C-statistics 0.584 (95%CI: 0.536 ~ 0.632) and 0.816 (95%CI: 0.781 ~ 0.851) were obtained by internal verification of the calibration curve, C-statistics revealed nomogram model validation was good and using decision curve analysis (DCA) confirmed a good predictive value of the nomogram models. In a nomogram model, ATL, UCd, sex, and age were detected as independent risk factors for renal function impairment, with UCd being the strongest predictor.

Prospective Associations of Early Pregnancy Metal Mixtures with Mitochondria DNA Copy Number and Telomere Length in Maternal and Cord Blood

BACKGROUND

Metal exposure during pregnancy influences maternal and child health. Oxidative stress and inflammation may mediate adverse effects of heavy metals, whereas essential metals may act as antioxidants. Mitochondrial DNA is a prime target for metal-induced oxidative damage. Telomere dysfunction is attributed to imbalances between reactive oxidant species and antioxidants.

OBJECTIVES

We evaluated individual and joint associations of prenatal metals with mitochondrial DNA copy number (mtDNAcn) and telomere length (TL) in maternal and cord blood as biomarkers of inflammation and oxidative stress.

METHODS

We measured six nonessential metals (arsenic, barium, cadmium, cesium, lead, mercury) and four essential metals (magnesium, manganese, selenium, zinc) in first-trimester maternal red blood cells in Project Viva, a U.S. prebirth cohort. We measured relative mtDNAcn (n=898) and TL (n=893) in second-trimester maternal blood and mtDNAcn (n=419) and TL (n=408) in cord blood. We used multivariable linear regression and quantile g-computation to estimate associations between prenatal metals and the biomarkers. We used generalized additive models and Bayesian kernel machine regression to examine nonlinearity and interactions.

RESULTS

A 2-fold increase in maternal magnesium was associated with lower maternal [β=-0.07, 95% confidence interval (CI): -0.10, -0.01] and cord blood (β=-0.08, 95% CI: -0.20, -0.01) mtDNAcn. Lead was associated with higher maternal mtDNAcn (β=0.04, 95% CI: 0.01, 0.06). Selenium was associated with longer cord blood TL (β=0.30, 95% CI: 0.01 0.50). An association was observed between the nonessential metal mixture and higher maternal mtDNAcn (β=0.04, 95% CI: 0.01, 0.07). There was a nonlinear relationship between cord blood mtDNAcn and magnesium; maternal mtDNAcn and barium, lead, and mercury; and maternal TL and barium.

DISCUSSION

Maternal exposure to metals such as lead, magnesium, and selenium was associated with mtDNAcn and TL in maternal second trimester and cord blood. Future work will evaluate whether these biomarkers are associated with child health. https://doi.org/10.1289/EHP9294.

Exposure to cadmium induces neuroinflammation and impairs ciliogenesis in hESC-derived 3D cerebral organoids

Cadmium (Cd) is an environmental heavy metal toxicant with central nervous system toxicity and has a greater negative impact on fetal neurodevelopment. However, the causative mechanisms for the neurodevelopmental toxicity of Cd have remained unclear. The human cerebral organoids can better mimic the three-dimensional structure of the early fetal nerve tissue, which can be used to study the developmental neurotoxicity under the condition of maternal exposure to Cd. Our study identified that Cd exposure specifically induced apoptosis in neurons and inhibited the proliferation of neural progenitor cells, but neural differentiation was not significantly affected in cerebral organoids. Cd exposure also elicited overexpression of GFAP, a marker of astrocytes and resulted in IL-6 release. This study revealed that mineral absorption was significantly disturbed with metallothioneins expression up-regulation. Moreover, we found Cd exposure inhibited cilium-related gene expression and reduced ciliary length with increasing dose. In conclusion, our study has shown that Cd exposure regulated neural cell proliferation and death, induced neuroinflammation, enhanced metal ion absorption, and impaired ciliogenesis, which hinder the normal development of the fetal brain.

Association between maternal urinary manganese concentrations and newborn telomere length: Results from a birth cohort study

OBJECTIVE

Telomere length (TL) is a biomarker for biological aging, and the initial setting of TL at birth is a determinant factor of TL in later life. Newborn TL is sensitive to maternal metals concentrations, while study about the association between maternal manganese (Mn) concentrations and newborn TL was not found. Our study aimed to investigate whether newborn TL is related to maternal Mn concentrations.

METHODS

Data were collected from a birth cohort study of 762 mother-newborn pairs conducted from November 2013 to March 2015 in Wuhan, China. We measured the Mn concentrations in spot urine samples collected during three trimesters by inductively coupled plasma mass spectrometry (ICP-MS) and relative cord blood TL by quantitative real-time polymerase chain reaction (qPCR). We applied multiple informant models to investigate the associations between maternal Mn concentrations and cord blood TL.

RESULTS

The geometric mean of creatinine-corrected urinary Mn concentrations were 1.58 μg/g creatinine, 2.53 μg/g creatinine, and 2.62 μg/g creatinine in the first, second, and third trimester, respectively. After adjusting for potential confounders, a doubling of maternal urinary Mn concentration during the second trimester was related to a 2.10% (95% CI: 0.25%, 3.99%) increase in cord blood TL. Mothers with the highest tertile of urinary Mn concentrations during the second trimester had a 9.67% (95% CI: 2.13%, 17.78%) longer cord blood TL than those with the lowest tertile. This association was more evident in male infants. No relationship was found between maternal urinary Mn concentrations and cord blood TL during the first and third trimesters in our study.

CONCLUSIONS

Our findings suggested that maternal Mn concentration during the second trimester was positively associated with newborn TL. These results might provide an epidemiology evidence on the protective role of maternal Mn for newborn TL and offer clues for the early prevention of telomere shortening related diseases.

Maternal overweight but not paternal overweight before pregnancy is associated with shorter newborn telomere length: evidence from Guangxi Zhuang birth cohort in China

Background

Telomere length (TL) is variable at birth and is inversely associated with body mass index (BMI) in adulthood. A growing number of evidences suggested that a higher maternal pre-pregnancy BMI results in adverse offspring health outcomes, especially shorter newborn TL. However, a newborn’s genetic endowment is equally derived from both parents, the association between parental pre-pregnancy BMI and newborn TL has been rarely discussed. We aimed to determine the association between parental pre-pregnancy BMI and newborn TL.

Methods

A total of 1082 parent-newborn pairs were recruited from the Guangxi Zhuang Birth Cohort (GZBC). TL in cord blood was measured using quantitative real-time polymerase chain reaction (qPCR) and expressed as the ratio of telomere copy number to single-copy gene number (T/S). A series of linear regressions were performed to assess the associations between parental pre-pregnancy BMI and newborn TL.

Results

Mothers who were overweight before pregnancy had significantly shorter cord blood telomere length in their newborns than those who were normal weight before pregnancy [percentage change: − 7.96% (95% CI: − 14.49 to − 0.69%; P = 0.032)]. Further analysis of the combined effects of parental weight status on newborn TL showed that TL was significantly shortened among newborns whose mothers were overweight and fathers were of healthy weight when compared with those whose mothers and fathers were both of normal weight [percentage change: − 8.38% (95% CI: − 15.47 to − 0.92%; P = 0.028)]. Subgroup analysis indicated these effects were more pronounced among male newborns and those whose paternal age < 31 years or maternal age ≥ 28 years at delivery.

Conclusions

Maternal pre-pregnancy overweight, but not paternal pre-pregnancy overweight is associated with shorter newborn TL. Weight control in reproductive women and effective healthy weight management before pregnancy may be of particular benefit for improving longevity and life quality of offspring.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-03757-x.

Environmental pollutants exposure: A potential contributor for aging and age-related diseases

Telomeres are "protective messengers" at the ends of eukaryotic chromosomes that protect them from degradation, end to end fusion and recombination. Admittedly, telomeres progressively shorten with age that can also be significantly accelerated by pathological conditions, which are often considered as potential contributors for cellular senescence. It is commonly believed that constant accumulation of senescent cells may lead to dysfunctional tissues and organs, thereby accelerating aging process and subsequent occurrence of age-related diseases. In particular, epidemiological data has indicated a significant association between environmental pollutants exposure and a high incidence of age-related diseases. Moreover, there is growing evidence that environmental toxicity has a detrimental impact on telomere length. Overall, a consensus is emerging that environmental pollutants exposure could lead to accelerated telomere erosion and further induce premature senescence, which may be responsible for the acceleration of aging and the high morbidity and mortality rates of age-related diseases.

The role of miRNAs in regulating the effect of prenatal cadmium exposure on ovarian granulosa cells in a transgenerational manner in female rats

Cadmium (Cd) is known to affect ovarian granulosa cells (GCs), but no information on the transgenerational effects of Cd on GCs. In this study, pregnant Sprague-Dawley (SD) rats were orally dosed with Cd from gestation day 1 until birth. F1 or F2 female rats were mated with untreated males to produce the F2 or F3 generation. In the F1 generation, apoptotic cell bodies were observed in the Cd-treated group but not in the F2 generation. Moreover, significant changes in B-cell lymphoma 2 (Bcl2) expression were observed in both generations. Additionally, the expression of microRNAs (miRNAs) was significantly changed based on microarray analysis. Specifically, miR-16-5p and miR-181b-5p were upregulated in F1 and F2 rats, while miR-92a-2-5p demonstrated different expression patterns between the two generations. In F3 generation, miR-16-5p and miR-92a-2-5p were down-regulated. Further, another experiment was used to show that miR-16-5p and miR-92a-2-5p regulated the Bcl2-induced apoptotic effect of Cd on GCs by the Human ovarian GC tumor line (COV434 cell line) miRNA-knockdown model Overall, the results indicate that prenatal Cd exposure has epigenetic transgenerational effect on GCs, Moreover, the underlying mechanism may involve interference with miR-16-5p and miR-92a-2-5p-mediated regulation of Bcl2 genes in offspring.

The association between prenatal exposure to thallium and shortened telomere length of newborns

BACKGROUND

Thallium is a widely known toxic heavy metal that has been reported have embryo toxicity.

OBJECTIVE

We aimed to investigate the relationship of prenatal thallium exposure with neonatal telomere length.

METHODS

A total of 746 mother-newborn pairs were recruited from Wuhan Children Hospital between November 2013 and March 2015 in Wuhan City, China. Maternal thallium exposure levels were measured in spot urine samples collected during the three trimesters and during hospital delivery using inductively coupled plasma mass spectrometry. Neonatal relative telomere length (rTL) was measured by a real-time quantitative polymerase chain reaction assay in cord blood. Multiple informant models were used to evaluate the association of maternal thallium exposure with neonatal rTL.

RESULTS

After adjustment for multiple potential confounders, each 25% incremental increase of maternal thallium exposure, measured in urine samples collected during hospital delivery, was associated with a 1.85% shortened neonatal rTL (95% CI: -3.62%, -0.05%; P = 0.044). Similarly, mothers in the highest quartile of urinary thallium exposure had a 11.74% (95% CI: -21.57%, -0.68%; P = 0.038) shorter cord blood leukocyte rTL than those in the lowest quartile. However, no significant association was found between neonatal rTL and maternal thallium exposure measured in urine samples collected during the three trimesters of pregnancy.

CONCLUSIONS

This study reveals that prenatal thallium exposure was related to shortened neonatal telomere length in Chinese population, pointing to the important role of thallium exposure in accelerating biological aging.

Role of maternal nutrition and oxidative stress in placental telomere attrition in women with preeclampsia

Background:Maternal nutrition influences the growth and development of the fetus and influences pregnancy outcome. We have earlier demonstrated altered maternal nutrition and increased oxidative stress in women with preeclampsia. Oxidative stress is known to be associated with reduced telomere length and short telomere aggregates. Increased telomere attrition leads to increased cellular senescence and tissue ageing. Methods:The present review focuses on the role of maternal nutrition and oxidative stress in telomere attrition in preeclampsia. Results and Conclusion:Future studies need to examine the association between maternal nutritional status in early pregnancy, oxidative stress and telomere attrition in preeclampsia.

Association between prenatal immune phenotyping and cord blood leukocyte telomere length in the PRISM pregnancy cohort

BACKGROUND

Environmental exposures including air pollutants, toxic metals, and psychosocial stress have been associated with shorter telomere length (TL) in newborns. These exposures have in turn been linked to an enhanced inflammatory immune response. Increased inflammation during pregnancy may be a central biological pathway linking environmental factors with reduced TL at birth. Approaches that more comprehensively characterize the prenatal inflammatory milieu rather than targeting specific individual cytokines in relation to newborn TL may better elucidate inflammatory mechanisms.

METHODS

Analyses included 129 mother-child dyads enrolled in the PRogramming of Intergenerational Stress Mechanisms (PRISM) pregnancy cohort. We measured 92 inflammation related proteins during pregnancy in maternal serum using the Olink protein array and quantified cord blood relative leukocyte TL (rLTL) via qPCR. We leveraged a tree-based machine learning algorithm to select the most important inflammatory related proteins jointly associated with rLTL. We then evaluated the combined association between the selected proteins with rLTL using Bayesian Weighted Quantile Sum (BWQS) Regression. Analyses were adjusted for gestational week of serum collection, maternal race/ethnicity, age, and education, and fetal sex. We evaluated major biological function of the identified proteins by using the UniProtKB, a centralized repository of curated functional information.

RESULTS

Three proteins were negatively and linearly associated with rLTL (CASP8 β: -0.22 p = 0.008, BNGF β: -0.43 p = 0.033, TRANCE β: 0.38 p = 0.004). Results from BWQS regression showed a significant overall decrease in rLTL (β: -0.26 95%CrI: -0.43, -0.07) per quartile increase of the mixture, with CASP8 contributing the greatest weight (CASP8 50%; BNGF 27%, and TRANCE 23%). The identified proteins were involved in the regulation of apoptotic processes and cell proliferation.

CONCLUSIONS

This proteomics approach identifies novel maternal prenatal inflammatory protein biomarkers associated with shortened rLTL in newborns.

Prenatal toxic metal mixture exposure and newborn telomere length: Modification by maternal antioxidant intake

BACKGROUND

Telomere length (TL) predicts the onset of cellular senescence and correlates with longevity and age-related disease risk. While telomeres erode throughout life, adults display fixed ranking and tracking of TL, supporting the importance of the early environment in determining inter-individual variability across the life course. Given their guanine-rich structure, telomeres are highly susceptible to oxidative stress (OS). We examined maternal metal exposure, which can induce OS, in relation to newborn TL. We also considered the modifying role of maternal antioxidant intake.

METHODS

Analyses included 100 mother-newborn pairs enrolled in the Boston and New York City-based PRogramming of Intergenerational Stress Mechanisms (PRISM) pregnancy cohort. We measured As, Ba, Cd, Ni, and Pb in maternal late-pregnancy urine by ICP-MS and quantified relative leukocyte TL (rLTL) in cord blood using qPCR. We used Weighted Quantile Sum (WQS) regression to estimate the metal mixture - rLTL association and conducted repeated holdout validation to improve the stability of estimates across data partitions. We examined models stratified by high (>median) versus low (≤median) maternal antioxidant intake, estimated from Block98 Food Frequency Questionnaires. We considered urinary creatinine, week of urine collection, maternal age, and race/ethnicity as covariates.

RESULTS

In adjusted models, urinary metals were inversely associated with newborn rLTL (βWQS = -0.50, 95% CI: -0.78, -0.21). The top metals contributing to the negative association included Ba (weight: 35.4%), Cd (24.5%) and Pb (26.9%). In models stratified by antioxidant intake, the significant inverse association between metals and rLTL remained only among mothers with low antioxidant intake (low: βWQS = -0.92, 95% CI: -1.53, -0.30; high: βWQS = -0.03, 95% CI: -0.58, 0.52). Results were similar in unadjusted models.

CONCLUSIONS

Relative LTL was shorter among newborns of mothers with higher exposure to metals during pregnancy. Higher maternal antioxidant intake may mitigate the negative influence of metals on newborn rLTL.

Telomere erosion as a placental clock: From placental pathologies to adverse pregnancy outcomes

The placenta provides nutritional and gas exchange between fetus and mother. Early in pregnancy, placental trophoblasts proliferate rapidly and invade aggressively. As pregnancy progresses, placental cells begin to age. Indeed, pregnancy itself has a tightly regulated duration, determined in large part by placental lifespan. Late in pregnancy, placental cells reach a senescent apoptotic state, activated by a number of intrinsic and extrinsic factors, including oxidative stress (OS), and DNA damage. Pregnancy complications, stillbirths and neonatal deaths have been related to OS and abnormal placental aging. Telomeres, the protective nucleoprotein structures at the ends of linear chromosomes, shorten both from cell replication and from exposure to OS. When telomeres become critically short they trigger cell cycle arrest and eventually cell death. Telomere attrition thus provide an intrinsic mechanism to explain tissue senescence and aging. Mounting evidence suggests that senescence of placental and fetal membrane cells results from telomere attrition. We review the studies that have addressed the role of telomere length (TL) in placentas from normal and complicated pregnancies, including pre-eclampsia, intrauterine growth restriction, gestational diabetes, and stillbirth. To date studies have uncovered associations between TL and a number of obstetrical complications. Future research is needed to determine whether these associations are causative, i.e. whether these clinical conditions result from telomere dysfunction, and whether particular features of telomeres, e.g. mean or shortest length, etc. could serve as clinically useful biomarkers of placental health.

Periconceptional environment predicts leukocyte telomere length in a cross-sectional study of 7-9 year old rural Gambian children

Early life exposures are important predictors of adult disease risk. Although the underlying mechanisms are largely unknown, telomere maintenance may be involved. This study investigated the relationship between seasonal differences in parental exposures at time of conception and leukocyte telomere length (LTL) in their offspring. LTL was measured in two cohorts of children aged 2 yrs (N = 487) and 7–9 yrs (N = 218). The association between date of conception and LTL was examined using Fourier regression models, adjusted for age, sex, leukocyte cell composition, and other potential confounders. We observed an effect of season in the older children in all models [likelihood ratio test (LRT) χ²₂ = 7.1, p = 0.03; fully adjusted model]. LTL was greatest in children conceived in September (in the rainy season), and smallest in those conceived in March (in the dry season), with an effect size (LTL peak–nadir) of 0.60 z-scores. No effect of season was evident in the younger children (LRT χ²₂ = 0.87, p = 0.65). The different results obtained for the two cohorts may reflect a delayed effect of season of conception on postnatal telomere maintenance. Alternatively, they may be explained by unmeasured differences in early life exposures, or the increased telomere attrition rate during infancy.

The environment as a determinant of successful aging or frailty

The number of elderly persons is rising rapidly, and healthspan is a key factor in determining the well-being of individuals and the sustainability of national health systems. Environmental health is crucial for a "successful aging". Complex relationships between environmental factors and non-communicable diseases play a major role, causing or accelerating disabilities. Besides genetic factors, aging results from the concurrence of several environmental factors starting from early (i.e. in utero) life, able to increase susceptibility to diseases in adulthood, and to promote frailty in the elderly. In aged people, an unhealthy environment contributes to a fast and early decline and increases vulnerability. Exposure to pollutants facilitates the onset and progression of cardiovascular, respiratory, metabolic and neurologic diseases through direct effects and epigenetic mechanisms negatively affecting biological age. Healthy diet, healthy environment and constant physical activity could counteract, at least in part, the negative effects of environmental stressors. Almost all environmental factors generating detrimental effects on aging are modifiable, with relevant implications in terms of primary prevention measures potentially leading to decreased frailty, to an increase in the number of years lived without diseases or disability, and to a significant reduction in health expenditure.

Protective role of selenium in the shortening of telomere length in newborns induced by in utero heavy metal exposure

The effects of toxic heavy metals, such as arsenic (As), cadmium (Cd), and lead (Pb), on telomere length (TL) have been reported previously. Although selenium (Se) is considered as an anti-oxidant which may detoxify the effects, there are no data on whether Se could protect against the TL-shortening effects of heavy metals. Thus, the aim of this study was to evaluate the protective role of Se against heavy metal-induced TL shortening. A birth cohort study was conducted in Myanmar in 2016, including 408 mother-infant pairs. First, pregnant women in the third trimester were interviewed concerning their socioeconomic, and pregnancy and birth characteristics using a pre-validated questionnaire. Maternal spot urine samples were collected after the interview. During the follow-up period (1-3 months), blood samples were collected from the umbilical cord at birth by local health workers. Metal concentrations were measured using inductively coupled plasma mass spectrometry (ICP-MS). TL was measured by quantitative real-time polymerase chain reaction (PCR). Relative TL was calculated as the ratio of telomere genes to single-copy genes. To evaluate the effect of Se on TL shortening, molar ratios were calculated. Linear regression analyses were performed to examine the associations between heavy metals and TL, individually and after adjustment for Se level. The effects of As, Cd, and Pb exposure on TL were smaller after adjustment for the Se level, especially for Pb (unadjusted β = -0.10; 95% CI: 0.18, -0.01; adjusted β = -0.03; 95% CI: 0.13, 0.05). On stratifying the data by Se concentration, there was no significant association between Cd or Pb exposure and TL in the high-Se group. Our study indicated a protective effect of Se against the TL shortening induced by heavy metal exposure, where the effect sizes were smaller after adjusting for the Se level, compared to individual metal exposure.

Early Biological Aging and Fetal Exposure to High and Low Ambient Temperature: A Birth Cohort Study

BACKGROUND

Although studies have provided estimates of premature mortality to either heat or cold in adult populations, and fetal exposure to ambient temperature may be associated with life expectancy, the effects of temperature on aging in early life have not yet been studied. Telomere length (TL) is a marker of biological aging, and a short TL at birth may predict lifespan and disease susceptibility later in life.

OBJECTIVES

We studied to what extent prenatal ambient temperature exposure is associated with newborn TL.

METHODS

In the ENVIRONAGE (ENVIRonmental influence ON early AGEing) birth cohort in Flanders, Belgium, we measured cord blood and placental TL in 1,103 mother-newborn pairs (singletons with ≥36wk of gestation) using a quantitative real-time polymerase chain reaction (qPCR) method. We associated newborn TL with average weekly exposure to ambient temperature using distributed lag nonlinear models (DLNMs) while controlling for potential confounders. Double-threshold DLNMs were used to estimate cold and heat thresholds and the linear associations between temperature and TL below the cold threshold and above the heat threshold.

RESULTS

Prenatal temperature exposure above the heat threshold (19.5°C) was associated with shorter cord blood TL. The association with a 1°C increase in temperature was strongest at week 36 of gestation and resulted in a 3.29% [95% confidence interval (CI): -4.67, -1.88] shorter cord blood TL. Consistently, prenatal temperature exposure below the cold threshold (5.0°C) was associated with longer cord blood TL. The association with a 1°C decrease in temperature was strongest at week 10 of gestation with 0.72% (95% CI: 0.46, 0.97) longer cord blood TL.

DISCUSSION

Our study supports potential effects of prenatal temperature exposure on longevity and disease susceptibility later in life. Future climate scenarios might jeopardize the potential molecular longevity of future generations from birth onward. https://doi.org/10.1289/EHP5153.

Exploring telomere length in mother-newborn pairs in relation to exposure to multiple toxic metals and potential modifying effects by nutritional factors

BACKGROUND

The uterine environment may influence telomere length at birth, which is essential for cellular function, aging, and disease susceptibility over the lifespan. However, little is known about the impact of toxic chemicals on early-life telomeres. Therefore, we assessed the potential impact of multiple toxic metals on relative telomere length (rTL) in the maternal blood, cord blood, and placenta, as well as the potential modifying effects of pro-oxidants.

METHOD

In a mother-child cohort in northern Argentina (n = 169), we measured multiple toxic metals in the maternal blood or urine collected during late pregnancy, as well as the placenta and cord blood collected at delivery, using inductively coupled plasma mass spectrometry (ICP-MS). We assessed associations of log₂-transformed metal concentrations with rTL, measured in maternal and cord blood leukocytes and the placenta by real-time PCR, using multivariable-adjusted linear regression. Additionally, we tested for modifications by antioxidants (zinc, selenium, folate, and vitamin D₃).

RESULTS

Exposure to boron and antimony during pregnancy was associated with shorter maternal rTL, and lithium with longer maternal rTL; a doubling of exposure was associated with changes corresponding to 0.2-0.4 standard deviations (SD) of the rTL. Arsenic concentrations in the placenta (n = 98), blood, and urine were positively associated with placental rTL, about 0.2 SD by doubled arsenic. In the cord blood (n = 88), only lead was associated with rTL (inversely), particularly in boys (p for interaction 0.09). Stratifying by newborn sex showed ten times stronger association in boys (about 0.6 SD) than in girls. The studied antioxidants did not modify the associations, except that with antimony.

CONCLUSIONS

Elevated exposure to boron, lithium, arsenic, and antimony was associated with maternal or newborn rTL in a tissue-specific, for lead also sex-specific, manner. Nutritional antioxidants did not generally influence the associations.