Exposure to multiple toxic metals and polycystic ovary syndrome risk: Endocrine disrupting effect from As, Pb and Ba

Correlation between mixed exposure to several heavy metals during early pregnancy and fetal low birth weight: Possible mediating effect of mitochondrial DNA copy number

BACKGROUND

Epidemiological investigations regarding the correlation between mixed heavy metals (HMs) exposure in early pregnancy and low birth weight (LBW) have shown contradictory findings. Moreover, investigations into the fundamental mechanisms, including the possible impacts of HMs exposure on mitochondrial DNA copy number (mtDNAcn), are limited.

OBJECTIVES

This study sought to examine the influence of mixed HMs exposure during early gestation on the prevalence of LBW and to ascertain whether mtDNAcn mediates this relationship.

METHODS

The Second Affiliated Hospital of Guilin Medical University conducted a nested case-control study involving 49 pregnant women who delivered LBW infants and 196 matched controls. Urine and blood samples were collected during early pregnancy, along with placental and umbilical cord blood samples at delivery. Concentrations of ten metals-magnesium(Mg), manganese(Mn), copper(Cu), arsenic(As), selenium(Se), strontium(Sr), molybdenum(Mo), cadmium(Cd), thallium(Tl), and lead(Pb)-were quantified. mtDNAcn was measured using real-time quantitative polymerase chain reaction (qPCR). Random forest analysis identified five metals-As, Se, Tl, Mn and Cd -as most strongly associated with the risk of preterm birth in LBW cases. These were selected for further analysis. Conditional logistic regression was applied to examine associations between early maternal urinary metal levels and infant malformations. To assess the combined effect of these metals on LBW, weighted quantile sum (WQS) regression and Bayesian kernel machine regression (BKMR) were used. Finally, mediation analysis was conducted to explore whether mtDNAcn mediated the relationship between Mn exposure and LBW.

RESULTS

The results of the study revealed a significant association between urinary Mn concentrations and LBW, with a p-value of0.015 and an odds ratio (OR) of 2.33 (95%CI:1.18-4.58) before adjusting for confounders. After adjusting for confounders, urinary manganese concentration remained significantly associated with LBW (p=0.017), with an OR of 2.36(95%CI:1.16-4.80). The odds of LBW significantly increased as exposure levels moved from the 25th to the 75th percentile for metal combinations, with the effect becoming more pronounced when the exposure index exceeded the 60th percentile. Notably, mtDNAcn levels mediated 27%of the association between Mn exposure and the incidence of umbilical cord bypass syndrome.

CONCLUSION

In conclusion, our data suggest that changes in mtDNAcn may mediate the association between Mn exposure during early pregnancy and the development of LBW. This study not only provides new evidence of the relationship between HMs exposure and fetal developmental disorders in China, but also serves as a valuable reference for global awareness regarding the effects of environmental pollution during pregnancy on fetal health.

Toxic metals and trace elements, markers of inflammation, and hyperandrogenemia in women and testosterone deficiency in men: Associations and potential mediating factors

There is evidence suggesting that toxic metal and trace element exposure disrupts androgen levels. However, specific effects of such exposure on hyperandrogenemia (HA) in women and testosterone deficiency (TD) in men remain unclear. The study investigated associations between toxic metal and trace element exposure and HA in women and TD in men, utilizing data from the National Health and Nutrition Examination Survey (NHANES) conducted between 2013 and 2016, and included 2205 women and 2621 men. Single-exposure analyses found lead (Pb) (adjusted odds ratio [aOR] 1.19, 95 % confidence interval [CI] 1.04-1.36) and cadmium (Cd) (aOR 1.20, 95 % CI 1.03-1.39) were positively associated with HA, especially strong in women over the age of 35. Manganese (Mn) was positively associated with TD (aOR 1.15, 95 % CI 1.03-1.28), especially strong in men aged between 45 and 50 years and obese men. A grouped weighted quantile sum (GWQS) model was performed to assess the effects of combined exposure, and found toxic metal mixture was positively associated with HA, particularly Cd (0.59) and Pb (0.40), and trace element mixture was positively associated with TD, particularly Mn (0.78). Mediation analyses demonstrated inflammation, particularly monocyte count and alkaline phosphatase (ALP) mediated 7.5-11.76 % of the associations. These findings provide insights to inform interventions for reducing exposure.

Changes in the global burden of polycystic ovary syndrome from 1990 to 2021

BACKGROUND

Polycystic ovary syndrome (PCOS) is a chronic, multifaceted condition influenced by epigenetic and environmental factors that is responsible for a significant proportion of anovulatory infertility cases. Here, we analyzed the global, regional, and national burdens of PCOS from 1990 to 2021 using data from the Global Burden of Disease 2021 (GBD 2021).

METHODS

Incidence, prevalence, and Disability-Adjusted Life Years (DALYs) data relevant to PCOS from 204 countries and 21 territories from 1990 to 2021 were obtained from the GBD 2021 study. Here, we considered age-standardized rates (per 100,000 individuals) with 95% uncertainty intervals (95% UIs) obtained from the aforementioned research and presented trends based on age and Socio-demographic Index (SDI) parameters.

RESULTS

In 2021, the global age-standardized incidence and prevalence rates of PCOS were 30.7 per 100,000 and 867.7 per 100,000, respectively, representing an increase of 26.77% and 28.21% since 1990. Additionally, age-standardized disability-adjusted life years stood at 7.6 per 100,000 globally in 2021, marking a 27.58% increase from 1990. Age-standardized prevalence of PCOS varied across countries, ranging from 93.1 to 3978.9 cases per 100,000 women, with Italy (3978.9), Japan (3104.7), and New Zealand (2789.7) having the highest rates. Notably, PCOS prevalence was noted to peak globally among females 15-19 years of age. Regions with a high SDI exhibited the highest age-standardized incidence (70.2), prevalence (1720.7), and DALY (15.2) rates of PCOS. Furthermore, a nonlinear correlation between PCOS burden and SDI was noted, with prevalence rates peaking around an SDI of approximately 0.9.

CONCLUSION

Our findings highlight the growing global impact of PCOS and underscore the need for concerted efforts to attenuate the increasing global prevalence of this condition. Significantly divergent PCOS disease burdens were observed across different age groups and SDI regions, with high SDI regions bearing heavier burdens. The increased disease burden among younger age groups and regional disparities underscore urgency for targeted intervention and formulation of policies to effectively address this public health issue.

A Prospective Ultrasound Study of Whole Blood Metals and Incidence of Uterine Leiomyomata

BACKGROUND

Uterine leiomyomata (UL), hormone-dependent neoplasms, are a major source of gynecologic morbidity. Metals are hypothesized to influence UL risk through endocrine disruption, and their effects may vary by vitamin D status.

OBJECTIVE

We estimated associations of a metal mixture with incident UL, overall and by vitamin D status.

METHODS

We analyzed data from the Study of Environment, Lifestyle and Fibroids, a Detroit-area prospective cohort study of 1,693 black women 23-35 years of age. We measured concentrations of 17 metals/metalloids in whole blood and 25-hydroxyvitamin D [25(OH)D] in serum collected at baseline (2010-2012). Participants underwent ultrasonography at baseline and after 20 months to detect UL. We used Bayesian kernel machine regression to estimate adjusted associations (β ) of the metal mixture with probit of incident UL. We also ran Cox regression models with interaction terms to estimate incidence rate ratios (IRR) by vitamin D status.

RESULTS

Among 1,132 UL-free participants at baseline, 832 (73%) had vitamin D deficiency [25(OH)D < 20  ng / mL ] and 117 (10%) developed UL within 20 months. Increasing all metals from their 50th to 75th percentiles was weakly positively associated with UL overall [β = 0.06 ; 95% credible interval (CrI): - 0.03 , 0.16] and among vitamin D-deficient participants (β = 0.13 ; 95% CrI: 0.01, 0.24), driven by cadmium (overall and vitamin D-deficient) and mercury (vitamin D-deficient only). Increasing cadmium from its 25th to 75th percentile was positively associated with UL overall (β = 0.03 ; 95% CrI: - 0.05 , 0.11) and among vitamin D-deficient participants (β = 0.13 , 95% CrI: 0.02, 0.24). In Cox models, cadmium [IRR = 1.55 ; 95% confidence interval (CI): 1.07, 2.24, per 1-unit increase in standardized concentration] and mercury (IRR = 1.38 ; 95% CI: 0.99, 1.92) were positively associated with UL among vitamin D-deficient participants.

DISCUSSION

The metal mixture was positively associated with incident UL, but the association was weak and imprecise. We observed a stronger association among vitamin D-deficient participants that was driven by cadmium and mercury. https://doi.org/10.1289/EHP15218.

Association between urinary arsenic and the prevalence of endometriosis in women in the United States

Background

Endometriosis affects up to 15% of women of reproductive age and can lead to various symptoms. More than 200 million people worldwide are at risk of higher than safe levels of arsenic exposure through drinking water. Studies investigating the relationship between arsenic and endometriosis are very limited and have yielded inconsistent results. This study aimed to explore the relationship between total urinary arsenic, arsenic species (Urinary arsenous acid, Urinary Arsenic acid, Urinary Arsenobetaine, Urinary Arsenocholine, Urinary Dimethylarsinic acid, Urinary Monomethylarsonic acid) and endometriosis.

Methods

We utilized a nationally representative dataset from the National Health and Nutrition Examination Survey (NHANES) from 2003 to 2006. A total of 650 participants were included. We examined the association between total urinary arsenic and different arsenic species with endometriosis using weighted multivariate logistic regression models.

Results

Urinary arsenous acid and urinary monomethylarsonic acid (MMA) were positively correlated with endometriosis (p < 0.05). After adjusting for potential confounding factors, the positive correlation of urinary MMA remained significant (OR: 1.317, 95%CI: 1.074-1.615). Subgroup analyses and interaction tests indicated that this association was not dependent.

Conclusion

Our research underscores a significant positive association observed between factors urinary MMA and endometriosis. Future research is needed to elucidate the specific mechanisms behind this association.

Associations between serum metal mixtures and systemic inflammation indices among Chinese early adolescents: A prospective cohort study

BACKGROUND

Research has demonstrated a link between metal exposure and inflammation. However, little is known about this relationship among adolescents, especially in prospective cohort studies. The aim of this study was to investigate the relationship between serum metal exposure and inflammatory status in Chinese early adolescents.

METHODS

In this study, 12 serum metals were detected at baseline in 1551 participants from the Chinese Early Adolescents Cohort. The participants' inflammatory status was assessed via three systemic inflammation indices (neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and systemic immune-inflammation index (SII)) at both baseline and follow-up. Generalized linear mixed models and restricted cubic splines regression were used to examine the linear and nonlinear relationships between single metal concentrations and systemic inflammation indices. Multiple mixture models were implemented to assess the relationships of mixed metals with systemic inflammation indices. Additionally, sex subgroup analyses were conducted to explore the sex-specific associations between serum metals and inflammatory status.

RESULTS

Single-exposure analysis revealed that exposure to multiple serum metals, such as chromium, cobalt, copper and lead, was positively associated with the NLR and SII, whereas iron was negatively correlated with the three systemic inflammation indices (PFDR<0.05). Additionally, inverted U-shaped associations were observed between vanadium, manganese and systemic inflammation indices. According to the mixture models, high levels of the serum metal mixture were positively correlated with the NLR and the SII. Cobalt had the highest positive weight in the mixed samples, whereas iron had the greatest negative weight in the serum-metal mixtures. Subgroup analyses revealed that serum exposure to the metal mixture had a more significant effect on systemic inflammation markers in females than in males.

CONCLUSIONS

This study reveals the impact of real-world mixed metal exposure on adolescents' inflammatory levels, which is of primary significance for protecting the healthy development of early adolescents.

Association Between Exposure to Multiple Toxic Metals in Follicular Fluid and the Risk of PCOS Among Infertile Women: The Mediating Effect of Metabolic Markers

Polycystic ovary syndrome (PCOS) severely affects women's fertility and accompanies serious metabolic disturbances, affecting 5%-20% of women of reproductive age globally. We previously found that exposure to toxic metals in the blood raised the risk of PCOS, but the association between exposure to toxic metals and the risk of PCOS in the follicular fluid, the microenvironment for oocyte growth and development in females, and its effect on metabolism has not been reported. This study aimed to evaluate the associations between the concentrations of cadmium (Cd), mercury (Hg), barium (Ba) and arsenic (As) in FF and the risk of PCOS, and to explore the mediating effect of metabolic markers in FF on the above relationship. We conducted a case-control study, including 557 women with PCOS and 651 controls. Ba, Cd, Hg and As levels in FF were measured by ICP-MS, metabolites levels in FF was measured by LC-MS/MS among 168 participants randomly selected from all the participants. Logistic regression models were used to assess the association of a single metal level with the PCOS risk, and linear regression models were used to assess the relationships of a single metal level with clinical phenotype parameters and metabolites levels. Combined effect of metals mixture levels on the risk of PCOS were assessed via weighted quantile sum (WQS) regression and bayesian kernel machine regression (BKMR). Medication analysis was performed to explore the role of metabolic markers on the relationship of toxic metals levels with the risk of PCOS. The exposure levels of Cd, Hg, Ba and As in FF were all positively and significantly associated with the PCOS risk (with respect to the highest vs. lowest tertile group: OR = 1.57, 95% CI = 1.17 ~ 2.12 for Cd, OR = 1.69, 95% CI = 1.22 ~ 2.34 for Hg, OR = 1.76, 95% CI = 1.32 ~ 2.34 for Ba, OR = 1.42, 95% CI = 1.05 ~ 1.91 for As). In addition, levels of metal mixture also significantly correlated with the risk of PCOS, Cd level contributed most to it. Moreover, we observed significant positive relationships between Cd level and LH (β = 0.048, 95% CI = 0.002 ~ 0.094), T (β = 0.077, 95% CI = 0.029 ~ 0.125) and HOMA-IR value (β = 0.060, 95% CI = 0.012 ~ 0.107), as well as Hg level with LH, FSH/LH ratio and TC. Furthermore, we revealed that estrone sulfate, LysoPE 22:6 and N-Undecanoylglycine were significantly and positively mediating the association between Cd level and the risk of PCOS (with mediated proportion of 0.39, 0.24 and 0.35, respectively), and between Hg level and the risk of PCOS (with mediated proportion of 0.29, 0.20 and 0.46, respectively). These highly expressed metabolites significantly enriched in the fatty acid oxidation, steroid hormone biosynthesis and glycerophospholipids metabolism, which may explain the reason why the levels of Cd and Hg in FF associated with the phenotype of PCOS. Ba and As in FF was not found the above phenomenon. Our results suggested that exposure to multiple toxic metals (Cd, Hg, Ba and As) in FF associated with the increased risk of PCOS, Cd was a major contributor. Levels of Cd and Hg in FF significantly associated with the phenotype of PCOS. The above association may result from that Cd and Hg in FF related with the disturbance of fatty acid oxidation, steroid hormone biosynthesis and the glycerophospholipids metabolism.

Association of Trace Elements with Polycystic Ovary Syndrome in Women-A Case-Control Study

Objectives: There are still limited or lacking data on the association of trace elements (TEs) with polycystic ovary syndrome (PCOS). This case-control study aimed to determine levels of essential TEs (manganese (Mn), copper (Cu), zinc (Zn), selenium (Se), molybdenum (Mo)) and non-essential TEs (arsenic (As), cadmium (Cd), mercury (Hg), lead (Pb)) in urine, whole blood, and serum to investigate a possible association with kidney and liver function, endocrine and metabolic parameters, and environmental and lifestyle sources of potential exposure and provide possible recommendations. Methods: In our case-control study, women with PCOS (n = 35) and healthy controls (n = 35) underwent clinical and ultrasonographic examination, filled in questionnaires targeting general, lifestyle, and environmental information, and provided fasting venous blood samples and first morning urine for biochemical, hormonal, and TE analysis. Multiple linear regression models were used to evaluate the association between TE levels and data obtained through questionnaires. Results: In women with PCOS, lower Mo levels in whole blood (p = 0.024) and serum (p = 0.011) and higher serum Cu levels (p = 0.026) were detected when compared to healthy controls. Results of this study show that amendments in Cu and Mo levels might be related to altered kidney and liver function and disrupted hormonal balance in PCOS women. Cu levels positively correlated with leukocyte count. There was a negative correlation of Mo levels with proteinuria and luteinizing hormone levels. Regarding liver function, Mo negatively correlated with urinary bilirubin levels, and there was a positive association with alanine and aspartate aminotransferase, respectively. Dietary supplement consumption and certain diet habits appeared to be important predictors of exposure to Cu (beef consumption) or Mo (cereal and boiled vegetable consumption) and modify Mo and Cu levels in women. Conclusions: Concentrations of the chemical elements Mo and Cu in biological samples of women appear to be related to PCOS and nutrition. To our knowledge, this is a novel finding for Mo. Additional research is needed to provide more insights into the causality of the PCOS relationship with Mo and Cu in humans.

Sex-specific associations between maternal exposure to metal mixtures and fetal growth trajectories: A prospective birth cohort study

BACKGROUND

The associations of prenatal metals exposure with birth outcomes have been widely assessed. However, evidence on the associations between metal mixtures and fetal intrauterine growth trajectories is scarce.

OBJECTIVES

This study aimed to explore the associations of metal mixtures with fetal intrauterine growth trajectories overall and by sex.

METHODS

We analyzed data from the Ma'anshan birth cohort, which included a total of 1041 pregnant woman. The concentrations of 12 metals in maternal blood were measured during early pregnancy, and fetal intrauterine growth indicators were standardized and assessed at 16, 23, 30, 34, and 38 weeks of gestation. We used generalized linear regression and linear mixed models to identify the key fetal growth indicator (biparietal diameter (BPD)), and applied GBTM to characterize BPD SD-scores trajectories. To further assess the individual and combined effects of metals, we conducted multivariable logistic regression and repeated holdouts weighted quantile sum (WQS) regression analyses, respectively. Finally, we performed a sex-stratified analysis to explore sex-specific associations.

RESULTS

The sex-stratified multivariable logistic regression analysis indicated that in male fetal, cobalt (Co) (OR: 0.60, 95 % CI: 0.38, 0.92) was negatively associated with the high-growth BPD-SD scores trajectory. In contrast, Co (OR: 2.39, 95 % CI: 1.40, 4.45) showed a positive association in female fetal. Results from the WQS showed that early pregnancy metal mixture exposure was associated with BPD-SD scores at 16, 34, and 38 weeks in female fetal. The results highlighted Zn and Co as key metals associated with high-growth BPD SD-scores trajectory. We also identified a significant interaction between early pregnancy metal mixtures and sex on high-growth BPD SD-scores trajectories. The WQS*sex interaction term had a mean odds ratio of 1.271 (95 % CI: 1.027, 1.619).

CONCLUSION

This study suggests that exposure to prenatal metal mixtures affects fetal intrauterine growth trajectories with sexual dimorphism.

Association between heavy metal exposure and bacterial vaginosis: A cross-sectional study

Bacterial vaginosis (BV) is a prevalent cause of vaginal symptoms in women of reproductive age. With the widespread of heavy metal pollutants and their harmful function on women's immune and hormonal systems, it is necessary to explore the association between heavy metal exposure and BV. This study investigates the potential relationship between serum heavy metals and bacterial vaginosis in a cohort of American women. The present study employed a cross-sectional analysis of 2,493 women participating in the 2001-2004 National Health and Nutrition Examination Survey (NHANES). Multivariable logistic regression models were utilized in the study to assess the correlation between these variables. A stratified analysis was performed to investigate the relationship among different population groups further, and smooth curve fittings were conducted to intuitively evaluate the correlation. According to the current cross-sectional study results, a significant correlation was identified between the high levels of lead and cadmium in the serum and the likelihood of developing bacterial vaginosis. We found that serum lead (OR = 1.35, 95% CI: 1.06-1.72, p = 0.016) and serum cadmium (OR = 1.41, 95% CI: 1.01-1.98, p = 0.047) increased the risk of bacterial vaginosis by 35% and 41%, respectively, in the highest level group in comparison to the lowest level group in the fully adjusted model. Furthermore, the research discovered no statistically significant association between the levels of total mercury in the serum and a heightened susceptibility to bacterial vaginosis (OR = 0.96, 95% CI: 0.75-1.23, p = 0.763). Results of our study indicated an inverse association between serum heavy metals and bacterial vaginosis risk, including lead and cadmium. Reducing exposure to heavy metals could be vital to preventing and managing bacterial vaginosis.

Exploring the role of rare earth elements (praseodymium, samarium, lanthanum, and terbium) and oxidative stress in polycystic ovary syndrome: A case-control study

BackgroundPraseodymium (Pr), Samarium (Sm), Lanthanum (La), and Terbium (Tb) are rare earth elements (REEs) that can accumulate in the body and induce oxidative stress (OS), which may contribute to polycystic ovary syndrome (PCOS), a condition affecting 116 million women worldwide. With the increasing use of REEs, understanding their role in PCOS is crucial.DesignThis case-control study included 56 PCOS cases and 50 healthy controls, with confounding factors such as age, BMI, and hormones controlled. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used to measure serum levels of Pr, Sm, La, and Tb, and Pearson correlation was performed to explore their relationship with oxidative stress markers such as malondialdehyde (MDA), glutathione (GSH), and superoxide dismutase (SOD).ResultA significant increase in serum levels of Pr, Sm, La, and Tb was observed in PCOS cases compared to controls (p < 0.05). The 95% confidence intervals (CIs) for the differences in serum Pr, Sm, La, and Tb levels were [0.0008, 0.0032], [0.0002, 0.0091], [0.0019, 0.0073], and [0.0002, 0.0129], respectively. Additionally, serum levels of MDA were significantly elevated, accompanied by reduction in the antioxidant markers-GSH and SOD (p < 0.001). Elevated REE levels were positively correlated with increased MDA and negatively correlated with GSH and SOD, indicating increased oxidative stress.ConclusionThese findings suggest that oxidative stress-induced metal intoxication may play a critical role in the development of PCOS. Future studies should explore the clinical significance of REE exposure and its potential as a target for preventive strategies in PCOS management.

Gestational exposure to arsenic reduces female offspring fertility by impairing the repair of DNA double-strand breaks and synapsis formation in oocytes

Arsenic is a pollutant that can cross the placenta; however, research on the effects of arsenic exposure during pregnancy on the fertility of female offspring is limited. To address this gap, we developed a mouse model to investigate the relationship between arsenic exposure during pregnancy and fertility in female offspring. Our fertility assessment revealed that gestational exposure to 1 mg/kg arsenic or higher (10 mg/kg) resulted in reduction in litter size, ovarian volume, and multistage-follicle number in female offspring. By assessing the in vitro developmental capacity of oocytes and zygotes, we confirmed that the reduced fertility was due not to impaired oocyte quality but rather to a reduction in oocyte quantity. Arsenic exposure impedes synapsis formation in MPI and compromises homologous recombination-mediated repair of double-strand breaks, resulting in fewer crossovers. This disruption activates the pachytene-checkpoint, hindering the progression of the MPI and resulting in the elimination of defective oocytes through p-Chk2 activation. Our study reveals for the first time the detrimental effects of arsenic exposure during pregnancy on the fertility of female offspring, underscoring the urgent need to prevent such exposure to safeguard reproductive health.

The relationships of metals exposure and disturbance of the vaginal microbiota with the risk of PROM: Results from a birth cohort study

The vaginal microbiota is proposed to be associated with reproductive health. Exposure to metals during pregnancy is a risk factor for premature rupture of membranes (PROM). PROM can lead to serious maternal complications, thus, identifying the cause and therapeutic targets for it is crucial. However, the role of vaginal microbiota in the association between metals exposure and the risk of PROM are not clear. Based on a prospective birth cohort study including 668 pregnant women, maternal blood levels of 15 metals in the first trimester (n=668) and microbiota of vaginal secretions in the third trimester (n=244) were assessed. The metals that significantly associated with the risk of PROM were screened out via four statistical models, the top three were barium (Ba), chromium (Cr) and thallium (Tl) according to their weight indices. The results from the BKMR model showed a positive association of the mixture (Ba, Cr and Tl) with the risk of PROM. PROM and non-PROM were characterised by different beta diversities, moreover, the relative abundances of Bifidobacterium, Corynebacterium and Collinsella were statistically and negatively related to the risk of PROM [the adjusted odds ratios (ORs) and 95 % confidence intervals (CIs) were 0.06 (0.00, 0.82), 0.32 (0.14, 0.74) and 0.50 (0.30, 0.84), respectively]. On the other hand, women with different levels of Ba exposure were also characterised by different beta diversities (p value = 0.047); and blood Ba levels were also negatively associated with the relative abundances of Collinsella; additionally, Cr levels were positively associated with alpha diversity indices [Shannon index: β (95 % CI) = 0.25 (0.01, 0.50); Simpson index: β (95 % CI) = 0.08 (0.00, 0.17), respectively]. The results from mediation analysis showed the proportion of the relationship between Ba exposure and PROM risk mediated by the relative abundance of Collinsella was 26.4 %. Further verification analysis exploring the potential cause of the above phenomenon indicated that the neutrophil count, one of blood inflammation indicators for PROM, was higher in women with the absence of Collinsella (p value = 0.039), moreover, the cumulative hazard of PROM for women with the presence of Collinsella was also significantly lower than that of those without Collinsella (p value = 0.007). Collectively, the changes in the diversity and composition of the bacterial community, especially the reduction in Collinsella abundance caused by metal exposure, may be related to the occurrence of PROM, which provides a new microbiota-based perspective for intervention in metal exposure-related PROM. Confirming these relationships and determining the possible processes at play will require more investigation.

Environmental Exposures and Polycystic Ovary Syndrome: A Review

Polycystic ovary syndrome (PCOS) is the most common heterogeneous endocrine disorder in women of reproductive age, affecting around 5 to 10% of women and up to 21% depending on the applied diagnostic criteria and study population. People with PCOS may experience oligomenorrhea, androgen excess, and polycystic ovary morphology. The etiology of the disease is not completely understood, with genetics, epigenetics, endocrine, metabolic, lifestyle, and environmental factors contributing to its development and severity. Environmental exposures are an important, burgeoning field in menstrual research, as they potentially link to menstrual cycle disruption and the risk of reproductive disorders such as PCOS. This review examines the recent research investigating environmental exposures-air pollution, micro- and nanoplastics, heavy metals, and endocrine-disrupting chemicals-and PCOS in human and animal models, concluding with potential mechanisms, limitations, and considerations for future work. Overall, research on environmental exposures and PCOS is limited and yields heterogeneous results across studies. Specifically, exposures such as air pollutants, micro- and nanoplastics, persistent organic pollutants, and parabens have noticeably limited research. Future research can help fill the gap in understanding how environmental exposures, particularly across gestational, childhood, and reproductive adult life stages, may impact PCOS.

Effects of Various Heavy Metal Exposures on Insulin Resistance in Non-diabetic Populations: Interpretability Analysis from Machine Learning Modeling Perspective

Increasing and compelling evidence has been proved that heavy metal exposure is involved in the development of insulin resistance (IR). We trained an interpretable predictive machine learning (ML) model for IR in the non-diabetic populations based on levels of heavy metal exposure. A total of 4354 participants from the NHANES (2003-2020) with complete information were randomly divided into a training set and a test set. Twelve ML algorithms, including random forest (RF), XGBoost (XGB), logistic regression (LR), GaussianNB (GNB), ridge regression (RR), support vector machine (SVM), multilayer perceptron (MLP), decision tree (DT), AdaBoost (AB), Gradient Boosting Decision Tree (GBDT), Voting Classifier (VC), and K-Nearest Neighbour (KNN), were constructed for IR prediction using the training set. Among these models, the RF algorithm had the best predictive performance, showing an accuracy of 80.14%, an AUC of 0.856, and an F1 score of 0.74 in the test set. We embedded three interpretable methods, the permutation feature importance analysis, partial dependence plot (PDP), and Shapley additive explanations (SHAP) in RF model for model interpretation. Urinary Ba, urinary Mo, blood Pb, and blood Cd levels were identified as the main influencers of IR. Within a specific range, urinary Ba (0.56-3.56 µg/L) and urinary Mo (1.06-20.25 µg/L) levels exhibited the most pronounced upwards trend with the risk of IR, while blood Pb (0.05-2.81 µg/dL) and blood Cd (0.24-0.65 µg/L) levels showed a declining trend with IR. The findings on the synergistic effects demonstrated that controlling urinary Ba levels might be more crucial for the management of IR. The SHAP decision plot offered personalized care for IR based on heavy metal control. In conclusion, by utilizing interpretable ML approaches, we emphasize the predictive value of heavy metals for IR, especially Ba, Mo, Pb, and Cd.

Analysis of Differential Gene Expression under Acute Lead or Mercury Exposure in Larval Zebrafish Using RNA-Seq

This study was first conducted to investigate the effects of acute lead exposure on developing zebrafish embryos or larvae from 24 to 120 h post-fertilization (hpf). Our data showed that treatment with 50-200 μM lead significantly affected larval survivability and morphology compared to the respective control. Second, we chose 120 hpf larvae treated with 12.5 μM lead for RNA sequencing due to its exposure level being sufficient to produce toxic effects with minimum death and lead bioaccumulation in developing zebrafish. A total of 137.45 million raw reads were obtained, and more than 86% of clean data were mapped to the zebrafish reference genome. Differential expression profiles generated 116 up- and 34 down-regulated genes upon lead exposure. The most enriched GO terms for representative DEGs were ion transport and lipid metabolism. Third, a comparison with the dataset of mercury-regulated gene expression identified 94 genes (64 up-regulated and 30 down-regulated) for exposure specific to lead, as well as 422 genes (338 up-regulated and 84 down-regulated) for exposure specific to mercury. In addition, 56 genes were co-regulated by micromolar mercury and lead treatment, and the expression of thirteen genes, including mt2, ctssb.1, prdx1, txn, sqrdl, tmprss13a, socs3a, trpv6, abcb6a, gsr, hbz, fads2, and zgc:92590 were validated by qRT-PCR. These genes were mainly associated with metal ion binding, proteolysis, antioxidant activity, signal transduction, calcium ion or oxygen transport, the fatty acid biosynthetic process, and protein metabolism. Taken together, these findings help better understand the genome-wide responses of developing zebrafish to lead or mercury and provide potential biomarkers for acute exposure to toxic metals.

Polycystic Ovarian Syndrome: Exploring Hypertension and Cardiometabolic Implications

Polycystic ovarian syndrome (PCOS) is the most common endocrine disorder affecting women of reproductive age, with significant implications for cardiometabolic health. This review focuses on the relationship between PCOS and hypertension (HTN), an area that remains underexplored despite growing evidence of its importance. PCOS is characterized by hyperandrogenism (HA), ovulatory dysfunction, and polycystic ovarian morphology (PCOM), all of which contribute to a complex metabolic profile that includes insulin resistance (IR), obesity, and dyslipidemia. These factors collectively exacerbate the risk of HTN. Emerging research suggests HA in PCOS may directly influence the renin-angiotensin system (RAS), increasing blood pressure by promoting sodium retention and vascular tone. Additionally, IR, prevalent in both lean and obese women with PCOS, further contributes to HTN by enhancing sympathetic nervous system activity and impairing endothelial function. Despite these associations, the direct link between PCOS and HTN has not been definitively established, warranting further investigation. This review synthesizes current knowledge on the etiology of PCOS and its metabolic consequences, highlighting the need for targeted research to clarify the mechanisms linking PCOS with HTN. Understanding these pathways is crucial for improving the management of PCOS and reducing cardiovascular risks in affected women. By addressing these gaps, this review underscores the importance of considering HTN as a significant comorbidity in PCOS and calls for more comprehensive studies to guide clinical practice.

Associations of insulin sensitivity and immune inflammatory responses with child blood lead (Pb) and PM2.5 exposure at an e-waste recycling area during the COVID-19 lockdown

Fine particular matter (PM2.5) and lead (Pb) exposure can induce insulin resistance, elevating the likelihood of diabetes onset. Nonetheless, the underlying mechanism remains ambiguous. Consequently, we assessed the association of PM2.5 and Pb exposure with insulin resistance and inflammation biomarkers in children. A total of 235 children aged 3-7 years in a kindergarten in e-waste recycling areas were enrolled before and during the Corona Virus Disease 2019 (COVID-19) lockdown. Daily PM2.5 data was collected and used to calculate the individual PM2.5 daily exposure dose (DED-PM2.5). Concentrations of whole blood Pb, fasting blood glucose, serum insulin, and high mobility group box 1 (HMGB1) in serum were measured. Compared with that before COVID-19, the COVID-19 lockdown group had lower DED-PM2.5 and blood Pb, higher serum HMGB1, and lower blood glucose and homeostasis model assessment of insulin resistance (HOMA-IR) index. Decreased DED-PM2.5 and blood Pb levels were linked to decreased levels of fasting blood glucose and increased serum HMGB1 in all children. Increased serum HMGB1 levels were linked to reduced levels of blood glucose and HOMA-IR. Due to the implementation of COVID-19 prevention and control measures, e-waste dismantling activities and exposure levels of PM2.5 and Pb declined, which probably reduced the association of PM2.5 and Pb on insulin sensitivity and diabetes risk, but a high level of risk of chronic low-grade inflammation remained. Our findings add new evidence for the associations among PM2.5 and Pb exposure, systemic inflammation and insulin resistance, which could be a possible explanation for diabetes related to environmental exposure.

Plastic-related endocrine disrupting chemicals significantly related to the increased risk of estrogen-dependent diseases in women

OBJECTIVE

To evaluate the association between exposure to plastic-related endocrine-disrupting chemicals (EDCs), specifically Bisphenol A (BPA), Phthalates, Cadmium, and Lead, and the risk of estrogen-dependent diseases (EDDs) such as polycystic ovary syndrome (PCOS), endometriosis, or endometrial cancer by conducting a meta-analysis of relevant studies.

METHODS

PubMed, Web of Science, and Cochrane Library databases were used for literature retrieval of articles published until the 21st of April 2023. Literature that evaluated the association between BPA, phthalates, cadmium, and/or lead exposure and the risk of PCOS, endometriosis, or endometrial cancer development or exacerbation were included in our analysis. STATA/MP 17.0 was used for all statistical analyses.

RESULTS

Overall, 22 articles were included in our meta-analysis with a total of 83,641 subjects all of whom were females aged between 18 and 83 years old. The overall effect size of each study was as follows: endometriosis risk in relation to BPA exposure ES 1.82 (95% CI; 1.50, 2.20). BPA and PCOS risk ES 1.61 (95% CI; 1.39, 1.85). Phthalate metabolites and endometriosis risk; MBP ES 1.07 (95% CI; 0.86, 1.33), MEP ES 1.05 (95% CI; 0.87, 1.28), MEHP ES 1.15 (95% CI; 0.67, 1.98), MBzP ES 0.97 (95% CI; 0.63, 1.49), MEOHP ES 1.87 (95% CI; 1.21, 2.87), and MEHHP ES 1.98 (95% CI; 1.32, 2.98). Cadmium exposure and endometrial cancer risk ES 1.14 (95% CI; 0.92, 1.41). Cadmium exposure and the risk of endometriosis ES 2.54 (95% CI; 1.71, 3.77). Lead exposure and the risk of endometriosis ES 1.74 (95% CI; 1.13, 2.69).

CONCLUSION

Increased serum, urinary, or dietary concentration of MBzP and MEHP in women is significantly associated with endometriosis risk. Increased cadmium concentration is associated with endometrial cancer risk.

Outdoor Artificial Light at Night and Reproductive Endocrine and Glucose Homeostasis and Polycystic Ovary Syndrome in Women of Reproductive Age

BACKGROUND

Artificial light at night, a well-recognized circadian clock disrupter, causes disturbances in endocrine homeostasis. However, the association of artificial light at night with polycystic ovary syndrome (PCOS) is still unknown. This study examines the effects of outdoor artificial light at night on sex hormones, glucose homeostasis markers, and PCOS prevalence in Anhui Province, China.

METHODS

We recruited 20,633 women of reproductive age from Anhui Medical University Reproductive Medicine Center. PCOS was diagnosed according to Rotterdam criteria. We estimated long-term (previous year) and short-term (previous month) artificial light at night values for residential addresses using 500 m resolution satellite imagery. We fitted multivariable models, using both linear and logistic regression, to estimate the association of artificial light at night with sex hormones, glucose homeostasis markers, and PCOS prevalence.

RESULTS

Both long-term and short-term exposure to outdoor artificial light at night were negatively associated with follicle-stimulating hormone and luteinizing hormone levels, while positively associated with testosterone, fasting insulin, homeostasis model assessment-insulin resistance, and homeostasis model assessment-insulin resistance-β levels. The second-highest quintile of artificial light at night was associated with increased PCOS prevalence (odds ratio [OR long-term ] = 1.4; 95% confidence interval [CI] = 1.2, 1.6 and OR short-term = 1.3; 95% CI = 1.1, 1.5) compared with the lowest quintile. In addition, prevalence of PCOS was linearly associated with long-term exposure to artificial light at night, but nonlinearly associated with short-term exposure. This association was more evident in younger, obese or overweight, moderately educated, rural women, and for the summer and fall seasons.

CONCLUSION

Outdoor artificial light at night may be a novel risk factor for PCOS.

Associations between follicular fluid trace elements and ovarian response during in vitro fertilization

INTRODUCTION

Exposure to trace elements has been associated with ovarian response in experimental studies. We conducted a hypothesis-generating study of associations between ovarian follicular fluid (FF) trace elements and measures of ovarian response among women using in vitro fertilization (IVF).

METHODS

We collected ovarian FF specimens from 56 women. We determined concentrations (μg/L) of 11 trace elements using inductively coupled plasma-tandem mass spectrometry. We estimated associations between women's FF trace elements per interquartile range difference, and measures of ovarian response using linear (peak estradiol (E2), baseline anti-mullerian hormone (AMH), and follicle stimulating hormone (FSH)) and negative binomial (baseline antral follicle count (AFC) and oocyte count) regression, adjusting for confounding factors. We used principal component analysis (PCA) to estimate the associations of the FF trace elements mixture. We also explored FF oxidative stress enzymes as causal mediators of the associations.

RESULTS

Higher FF cobalt was associated with greater peak E2 (mean difference = 351.48 pg/mL; 95%CI: 21.76, 724.71) and AFC (rate ratio = 1.14; 95%CI: 1.01, 1.28), and higher FF copper was associated with greater peak E2 (mean difference = 335.66 pg/mL; 95%CI: 81.77, 753.08) and oocyte count (rate ratio = 1.19; 95%CI: 1.02, 1.43). Higher FF mercury was also associated with greater peak E2 (mean difference = 410.70 pg/mL; 95%CI: 61.90, 883.39). Higher FF lead was associated with lesser AFC (rate ratio = 0.85; 95%CI: 0.73, 0.98). Using PCA, the mixture of Sr, Hg, and As was associated with higher peak estradiol, AFC, and oocyte count. FF glutathione peroxidase, paraoxonase, and arylesterase activities were inconsistent mediators of the associations, but the effect estimates were imprecise.

CONCLUSION

Our results suggest that essential and non-essential trace elements in FF were associated with ovarian response during IVF.

Alkali and alkaline earth elements in follicular fluid and the likelihood of diminished ovarian reserve in reproductive-aged women: a case‒control study

BACKGROUND

Imbalances in alkali elements (AEs) and alkaline earth elements (AEEs) cause reproductive disorders. However, it remains unclear whether AEs/AEEs in follicular fluid have a relationship with the serious reproductive disorder known as diminished ovarian reserve (DOR).

METHODS

A nested case‒control study was carried out in China. Follicular fluid samples from 154 DOR patients and 154 controls were collected and assessed for nine AEs/AEE levels. Both the mixed and single effects of the elements on DOR were estimated with a Bayesian kernel machine (BKMR) and logistic regressions.

RESULTS

The DOR group had higher median concentrations of Li, Na, and K in follicular fluid (all P values < 0.05). The logistic regression showed that compared with their lowest tertile, the high tertiles of K [OR:2.45 (1.67-4.43)], Li [OR: 1.89 (1.06-3.42)], and Cs [OR: 1.97 (1.10-3.54)] were significantly associated with the odds of DOR. The BKMR model reported that the DOR likelihood increased linearly across the 25th through 75th percentiles of the nine-AE/AEE mixture, while the AE group contributed more to the overall effect.

CONCLUSION

This study revealed an association in which the likelihood of DOR increased with higher overall concentrations of AE/AEEs in follicular fluid. Among the nine detected elements, K, Li, and Cs exhibited significant individual associations with DOR. We provide new clues for the environmental factors on female fertility decline.

TRIAL REGISTRATION

Retrospectively registered.

Levels of trace metals and their impact on oocyte: A review

Trace metals play a vital role in a variety of biological processes, but excessive amounts can be toxic and are receiving increasing attention. Trace metals in the environment are released from natural sources, such as rock weathering, volcanic eruptions, and other human activities, such as industrial emissions, mineral extraction, and vehicle exhaust. Lifestyle, dietary habits and environmental quality are the main sources of human exposure to trace metals, which play an important role in inducing human reproductive infertility. The purpose of this review is to summarize the distribution of various trace metals in oocyte and to identify the trace metals that may cause oocyte used in the design and execution of toxicological studies.

Association of exposure to multiple heavy metals during pregnancy with the risk of gestational diabetes mellitus and insulin secretion phase after glucose stimulation

BACKGROUND

Epidemiological evidence for the association between heavy metals exposure during pregnancy and gestational diabetes mellitus (GDM) is still inconsistent. Additionally, that is poorly understood about the potential cause behind the association, for instance, whether heavy metal exposure is related to the change of insulin secretion phase is unknown.

OBJECTIVES

We aimed to explore the relationships of blood levels of arsenic (As), lead (Pb), thallium (Tl), nickel (Ni), cadmium (Cd), cobalt (Co), barium (Ba), chromium (Cr), mercury (Hg) and copper (Cu) during early pregnancy with the odds of GDM, either as an individual or a mixture, as well as the association of the metals with insulin secretion phase after glucose stimulation.

METHODS

We performed a nested case-control study consisting of 302 pregnant women with GDM and 302 controls at the First Affiliated Hospital of Anhui Medical University in Hefei, China. Around the 12th week of pregnancy, blood samples of pregnant women were collected and levels of As, Pb, Tl, Ni, Cd, Co, Ba, Cr, Hg and Cu in blood were measured. An oral glucose tolerance test (OGTT) was done in each pregnant woman during the 24-28th week of pregnancy to diagnose GDM and C-peptide (CP) levels during OGTT were measured simultaneously. The four metals (As, Pb, Tl and Ni) with the highest effect on odds of GDM were selected for the subsequent analyses via the random forest model. Conditional logistic regression models were performed to analyze the relationships of blood As, Pb, Tl and Ni levels with the odds of GDM. The weighted quantile sum (WQS) regression and bayesian kernel machine regression (BKMR) were used to assess the joint effects of levels of As, Pb, Tl and Ni on the odds of GDM as well as to evaluate which metal level contributed most to the association. Latent profile analysis (LPA) was conducted to identify profiles of glycemic and C-peptide levels at different time points. Multiple linear regression models were employed to explore the relationships of metals with glycaemia-related indices (fasting blood glucose (FBG), 1-hour blood glucose (1h BG), 2-hour blood glucose (2h BG), fasting C-peptide (FCP), 1-hour C-peptide (1h CP), 2-hour C-peptide (2h CP), FCP/FBG, 1h CP/1h BG, 2h CP/2h BG, area under the curve of C-peptide (AUCP), area under the curve of glucose (AUCG), AUCP/AUCG and profiles of BGs and CPs, respectively. Mixed-effects models with repeated measures data were used to explore the relationship between As (the ultimately selected metal) level and glucose-stimulated insulin secretion phase. The mediation effects of AUCP and AUCG on the association of As exposure with odds of GDM were investigated using mediation models.

RESULTS

The odds of GDM in pregnant women increased with every ln unit increase in blood As concentration (odds ratio (OR) = 1.46, 95% confidence interval (CI) = 1.04-2.05). The joint effects of As, Pb, Tl and Ni levels on the odds of GDM was statistically significant when blood levels of four metals were exceeded their 50th percentile, with As level being a major contributor. Blood As level was positively associated with AUCG and the category of glucose latent profile, the values of AUCG were much higher in GDM group than those in non-GDM group, which suggested that As exposure associated with the odds of GDM may be due to that As exposure was related to the impairment of glucose tolerance among pregnant women. The significant and positive relationships of As level with AUCP, CP latent profile category, 2h CP and 2h CP/2h BG were observed, respectively; and the values of 1h CP/1h BG and AUCP/AUCG were much lower in GDM group than those in non-GDM group, which suggested that As exposure may not relate to the impairment of insulin secretion (pancreatic β-cell function) among pregnant women. The relationships between As level and 2h CP as well as 2h CP/2h BG were positive and significant; additionally, the values of 2h CP/2h BG in GDM group were comparable with those in non-GDM group; the peak value of CP occurred at 2h in GDM group, as well as the values of 2h CP/2h BG in high As exposure group were much higher than those in low As exposure group, which suggested that As exposure associated with the increased odds of GDM may be due to that As exposure was related to the change of insulin secretion phase (delayment of the peak of insulin secretion) among pregnant women. In addition, AUCP mediated 11% (p < 0.05) and AUCG mediated 43% (p < 0.05) of the association between As exposure and the odds of GDM.

CONCLUSION

Our results suggested that joint exposure to As, Pb, Tl and Ni during early pregnancy was positively associated with the odds of GDM, As was a major contributor; and the association of environmental As exposure with the increased odds of GDM may be due to that As exposure was related to the impairment of glucose tolerance and change of insulin secretion phase after glucose stimulation (delayment of the peak of insulin secretion) among pregnant women.

Lead exposure aggravates glucose metabolism disorders through gut microbiota dysbiosis and intestinal barrier damage in high-fat diet-fed mice

BACKGROUND

Lead (Pb) is an ancient toxic metal and is still a major public health issue. Our previous study found that Pb exposure promotes metabolic disorders in obese mice, but the molecular mechanisms remain unclear. The present study explored the effects of Pb exposure on glucose homeostasis in mice fed a normal diet (ND) and high-fat diet (HFD) from the perspective of gut microbiota.

RESULTS

Pb exposure had little effect on glucose metabolism in ND mice, but exacerbated hyperglycemia and insulin resistance, and impaired glucose tolerance in HFD mice. Pb exposure impaired intestinal tight junctions and mucin expression in HFD mice, increasing intestinal permeability and inflammation. Moreover, Pb exposure altered the composition and structure of the gut microbiota and decreased short-chain fatty acids (SCFAs) levels in HFD mice. Correlation analysis revealed that the gut microbiota and SCFAs were significantly correlated with the gut barrier and glucose homeostasis. Furthermore, the fecal microbiota transplantation from Pb-exposed HFD mice resulted in glucose homeostasis imbalance, intestinal mucosal structural damage and inflammation in recipient mice. However, Pb did not exacerbate the metabolic toxicity in HFD mice under depleted gut microbiota.

CONCLUSION

The findings of the present study suggest that Pb induces impairment of glucose metabolism in HFD mice by perturbing the gut microbiota. Our study offers new perspectives on the mechanisms of metabolic toxicity of heavy metals and demonstrates that the gut microbiota may be a target of action for heavy metal exposure. © 2023 Society of Chemical Industry.

Comprehensive analysis of ovarian granulosa cell proteomics and phosphoproteomics in PCOS patients without insulin resistance

PCOS is a complex and heterogeneous metabolic disorder that affects 6-20% of women of reproductive age. However, research on phosphorylation modification proteomics in PCOS remains lacking. PCOS can be divided into two groups based on the presence or absence of insulin resistance: PCOS with insulin resistance (PCOS-IR) and PCOS non-insulin resistant (PCOS-NIR). This study focused on the group without insulin resistance. Twenty-one PCOS-NIR and 39 control-NIR (Ctrl-NIR) patients were included in this study. All participants underwent ICSI or IVF-embryo transfer (IVF-ET) treatment in a reproductive center from July 2020 to November 2020. During oocyte retrieval, fresh follicular fluid was aspirated, collected, and sent to the laboratory for analysis of the granulosa cells. A 4D-label-free proteome quantification method was performed in this study; this was used to analyze protein enzymatic peptide fragments by liquid chromatography-mass spectrometry (LC-MS). Bioinformatic analysis was performed on differentially expressed proteins (DEPs) and differentially phosphorylated proteins (DPPs). A total of 713 DEPs were identified between the two groups, including 293 upregulated and 420 downregulated DEPs in the PCOS-NIR group. There were 522 and 159 proteins with increased and decreased phosphorylation, respectively, in the PCOS-NIR group. After analyzing the different phosphorylation modification sites, 933 sites with upregulated and 211 sites with downregulated phosphorylation were found in the PCOS-NIR group. In this study, we describe the quantitative protein expression profiles and phosphorylation-modified protein expression profiles of ovarian granulosa cells from patients with PCOS-NIR, providing a new research perspective for these patients. Further studies are required to elucidate the role of protein phosphorylation in PCOS.

Analysis of Relationships between Metabolic Changes and Selected Nutrient Intake in Women Environmentally Exposed to Arsenic

Nutrients involved in the metabolism of inorganic arsenic (iAs) may play a crucial role in mitigating the adverse health effects associated with such exposure. Consequently, the objective of this study was to analyze the association between the intake levels of nutrients involved in iAs metabolism and alterations in the metabolic profile during arsenic exposure. The study cohort comprised environmentally exposed women: WL (lower total urinary arsenic (As), n = 73) and WH (higher As, n = 73). The analysis included urinary untargeted metabolomics (conducted via liquid chromatography-mass spectrometry) and the assessment of nutrient intake involved in iAs metabolism, specifically methionine, vitamins B2, B6, and B12, folate, and zinc (based on 3-day dietary records of food and beverages). In the WL group, the intake of all analyzed nutrients exhibited a negative correlation with 5 metabolites (argininosuccinic acid, 5-hydroxy-L-tryptophan, 11-trans-LTE4, mevalonic acid, aminoadipic acid), while in the WH group, it correlated with 10 metabolites (5-hydroxy-L-tryptophan, dihyroxy-1H-indole glucuronide I, 11-trans-LTE4, isovalerylglucuronide, 18-oxocortisol, 3-hydroxydecanedioic acid, S-3-oxodecanoyl cysteamine, L-arginine, p-cresol glucuronide, thromboxane B2). Furthermore, nutrient intake demonstrated a positive association with 3 metabolites in the WL group (inosine, deoxyuridine, glutamine) and the WH group (inosine, N-acetyl-L-aspartic acid, tetrahydrodeoxycorticosterone). Altering the intake of nutrients involved in iAs metabolism could be a pivotal factor in reducing the negative impact of arsenic exposure on the human body. This study underscores the significance of maintaining adequate nutrient intake, particularly in populations exposed to arsenic.

Evidence-based identification of breast cancer and associated ovarian and uterus cancer risk components in source waters from high incidence area in the Pearl River Basin, China

Breast cancer, ovarian cancer, and uterus cancer are among the most common female cancers. They are suspected to associate with exposures to specific environmental pollutants, which remain unidentified in source waters. In this work, we focused on the Pearl River Basin region in China, which experienced a high incidence of breast, ovarian, and uterus cancers. Combining cancer patient data, mammalian cell cytotoxicity analyses, and exhaustive historical and current chemical assessments, we for the first time identified source water components that promoted proliferation of mammalian cells, and confirmed their association with these female cancers via the estrogen receptor mediated pathway. Therefore, the components that have previously been found to enhance the proliferation of estrogen receptor-containing cells through endocrine disruption could be the crucial factor. Based on this, components that matched with this toxicological characteristic (i.e., estrogen-like effect) were further identified in source waters, including (1) organic components: phthalates, bisphenol A, nonylphenols, and per-/polyfluoroalkyls; (2) inorganic components: Sb, Co, As, and nitrate. Moreover, these identified water components were present at levels comparable to other regions with high female cancer prevalence, suggesting that the potential risk of these components may not be exclusive to the study region. Together, multiple levels of evidence suggested that long-term co-exposures to source water estrogenic components may be important to the development of breast, ovarian, and uterus cancers.

Hormonal Injustice: Environmental Toxicants as Drivers of Endocrine Health Disparities

The toll of multiple endocrine disorders has increased substantially in recent decades, and marginalized populations bear a disproportionate burden of disease. Because of the significant individual and societal impact of these conditions, it is essential to identify and address all modifiable risk factors contributing to these disparities. Abundant evidence now links endocrine dysfunction with exposure to endocrine-disrupting chemicals (EDCs), with greater exposures to multiple EDCs occurring among vulnerable groups, such as racial/ethnic minorities, those with low incomes, and others with high endocrine disease burdens. Identifying and eliminating EDC exposures is an essential step in achieving endocrine health equity.

Association between heavy metal exposures and the prevalence of pelvic inflammatory disease: a cross-sectional study from the National Health and Nutrition Examination Survey 2013-2018

Pelvic inflammatory disease (PID) is a common medical condition in women. However, the correlation between exposure to heavy metals, including cadmium (Cd), lead (Pb), manganese (Mn), mercury (Hg), and selenium (Se), and PID, is unclear. Using a large sample size from the National Health and Nutrition Examination Survey, these relationships were studied and verified. PID diagnosis was acquired through a self-reported questionnaire (2013-2018). Heavy metal exposure (Cd, Pb, Mn, Hg, and Se) was measured using mass spectrometry of blood samples. Covariate data were obtained through questionnaires and physical tests. Individuals with complete covariate data were included in the study. The relationship between heavy metal exposure (Cd, Pb, Mn, Hg, and Se) and PID was demonstrated using logistic regression analysis, weighted quantile sum (WQS) regression analysis, and restricted cubic splines (RCS). Overall, 2743 participants were included. Of these, 183 were diagnosed with PID. Through weighted univariate and multivariate regression analyses, the heavy metals of Cd and Pb were positively correlated with the prevalence of PID. However, no significant relationship was observed in the heavy metals of Mn, Hg, and Se. The joint effect of heavy metals further confirmed the important role of Cd and Pb in WQS analysis. After visualizing the RCS, significant curved and linear relationships were observed for Cd and Pb, respectively. Most subgroup analyses confirmed these results. In conclusion, exposure to Cd was nonlinearly correlated with the risk of PID, whereas exposure to Pb showed a linear relationship. Our findings increase the awareness of the environmental effects of exposure to heavy metals in PID. However, further studies are needed to elucidate the causality and underlying mechanisms between heavy metal exposure and the prevalence of PID.

The ionome and proteome landscape of aging in laying hens and relation to egg white quality

The ionome is essential for maintaining body function and health status by participating in diverse key biological processes. Nevertheless, the distribution and utilization of ionome among different organs and how aging impacts the ionome leading to a decline in egg white quality remain unknown. Thus, we used inductively coupled plasma mass spectrometry (ICP-MS) to analyze 35 elements and their isotopic contents in eight organs of laying hens at 35, 72, and 100 weeks. Moreover, the magnum proteome, amino acids in egg white, and egg white quality were analyzed in laying hens at three different ages using 4D proteomics techniques, an amino acid analyzer, and an egg quality analyzer. Across the organs, we identified varying distribution patterns among macroelements (Mg24, Ca43/44, K39, and P31), transition metals (Zn64/66, Cu63/65, Fe56/57, and Mn55), and toxic elements (Pb208, Ba137, and Sr86). We observed an organ-specific aging pattern characterized by the accumulation of toxic elements (Pb208, Ba137, and Sr86) and calcification in the small intestine. Additionally, a decrease in the utilization of essential trace elements selenium (Se78/82) and manganese (Mn55) was noted in the oviduct. By analyzing ionome in tandem with egg quality, egg white amino acids, and proteome, we unveiled that the reduction of selenium and manganese concentrations in the magnum during the aging process affected amino acid metabolism, particularly tryptophan metabolism, thereby inhibiting the amino acid synthesis in the magnum. Furthermore, it accelerated the senescence of magnum cells through necroptosis activation, leading to a decline in the albumen secretion function of the magnum and subsequently reducing egg white quality. Overall, this study provides insights into the evolution of 35 elements and their isotopes across 8 organs of laying hens with age. It also reveals the elemental composition, interactions, and utilization patterns of these organs, as well as their correlation with egg white quality. The present study highlights the significance of ionome and offers a comprehensive perspective on the selection of ionome for regulating the aging of laying hens.

Production of biochar from tropical fruit tree residues and ecofriendly applications - A review

Environmental contamination is considered a major issue with the growing urbanization and industrialization. In this context, the scientific society is engaged in searching for a sustainable, safe, and eco-friendly solution. Sustainable materials such as biochar play an important role in environmental contamination. It has some specific properties such as micropores which increase the surface area to bind the pollutants. This review endeavors to analyze the potential of fruit wastes especially tropical fruit tree residues as potential candidates for producing highly efficient biochar materials. The review discusses various aspects of biochar production viz. pyrolysis, torrefaction, hydrothermal carbonization, and gasification. In addition, it discusses biochar use as an adsorbent, wastewater treatment, catalyst, energy storage, carbon sequestration and animal feed. The review put forward a critical discussion about key aspects of applying biochar to the environment.

Heavy Metal(loid) Accumulation in the Ovarian Tissue of Free-Ranging Queens and Bitches Inhabiting Highly Polluted Urban Environments

There is strong scientific evidence that exposure to environmental contaminants, such as heavy metal(loid)s (HMs), can impair female reproductive function. Pets, such as cats and dogs, who share the same habitat as humans, may be particularly useful sentinel models for detecting HMs in the ovary. In the present study, we compared the concentration of essential (Ems; Cu, Fe, Mn, Se, and Zn) and non-essential metal(loid)s (NEMs; Al, As, Cd, and Pb) in the ovarian tissues of free-ranging queens and bitches of different ages living in industrialized/highly polluted (south group) and non-polluted (north group) urban areas of the island of Sardinia, Italy. The results showed that both EMs and NEMs were present at detectable concentrations in feline and canine ovaries and their levels varied according to geographical areas and animal age. Among the EMs, Cu was found elevated in older queens and bitches inhabiting the southern area. Cadmium and lead were higher in feline and canine ovaries of older animals from the south compared to those living in the north. In addition, Cd and Pb concentrations increased in individuals of both species living in the south. These findings showed new perspectives for the use of pets as early warning sentinels of environmental pollution by HMs and for the risk of human exposure within a "One Health" approach. Pets may help to study the link between exposure to metals and female reproductive disturbances in mammals.

A global perspective of correlation between maternal blood lead levels and risks of preeclampsia: An updated systematic review and meta-analysis

Background

Preeclampsia (PE) is a specific hypertensive disorder in pregnancy. Lead (Pb) is a heavy metal that affects women's reproductive health. However, it is unclear whether lead exposure during can predispose maternal risk of developing preeclampsia. This systematic review and meta-analysis study aimed to explore the association.

Methods

We searched studies from three databases (PubMed, Web of Science, Embase). Only case-control, cross-sectional, and cohort studies reporting maternal blood lead levels (BLL) and PE were included from database inception to 31st July 2022. Pregnant women with blood lead levels measured were eligible. Those healthy pregnant women who did not develop preeclampsia were assessed as comparators. Letters, comments, case reports, and reviews were excluded. Newcastle-Ottawa Scale (NOS) and its adaptive form were applied for assessment. The random-effects method (REM) was applied to calculate the standardized mean difference (SMD) with a 95% confidence interval (CI). Stata 16.0 and RevMan 5.3 were the software used for data extraction and analysis.

Results

25 studies out of 1,808 articles made the finalist for systematic reviews, of which 21 underwent further quantity analysis. A total of 1,533 preeclamptic women and 10,998 healthy pregnant controls were included in the meta-analysis. The overall result revealed that maternal lead exposure was significantly higher in women with preeclampsia (SMD: 1.06, 95% CI 0.69, 1.43); (I ² = 96.40%; P = 0.000).

Conclusion

This study demonstrates that maternal lead exposure is associated with preeclampsia during pregnancy. The association is present even in low blood lead levels. The conclusion should be taken seriously and women should avoid unexpected exposure to a lead-containing environment as much as possible.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=347220, identifier: CRD42022347220.