Obesity aggravates toxic effect of BPA on spermatogenesis

Perfluorohexane Sulfonic Acid Disrupts the Immune Microenvironment for Spermatogenesis by Damaging the Structure of the Blood-Testis Barrier in Mice

Perfluorohexane sulfonic acid (PFHxS) is extensively used in waterproof coatings and fire-fighting foams, and several studies have found it to be a potential health hazard, but there is still unknown about its effects on spermatogenesis. Our results showed that PFHxS-treated mice have significant reproductive toxicity, including a decrease in sperm count and motility, and the levels of sex hormones (P < 0.05). Concurrently, structural abnormalities are observed in sperm, affecting ≈60-75% of those in the PFHxS-treated group. Additionally, it is found that the structure of the blood-testis barrier (BTB) is damaged after PFHxS treatment, leading to higher expression levels of inflammatory cytokines in the microenvironment for spermatogenesis. Moreover, the expression of proteins associated with mitochondrial biogenesis, including PTEN-induced kinase 1 (PINK1) and NADPH oxidase 4 (NOX4), is dysregulated in the testes after PFHxS treatment. Based on metabolome data, the differential metabolite 3-hydroxybutanoic acid is identified in the PFHxS-treated group, which can regulate the histone Kac levels, especially H3K4ac and H3K9ac. In summary, the results of this study suggest that in the testes of PFHxS-treated mice, inflammatory factors disrupt the mitochondrial function and metabolic profiles and hinder the progress of gene transcription through histone Kac, ultimately causing sperm dysfunction.

Reproductive and Metabolic Health Following Exposure to Environmental Chemicals: Mechanistic Insights from Mammalian Models

The decline in human reproductive and metabolic health over the past 50 years is associated with exposure to complex mixtures of anthropogenic environmental chemicals (ECs). Real-life EC exposure has varied over time and differs across geographical locations. Health-related issues include declining sperm quality, advanced puberty onset, premature ovarian insufficiency, cancer, obesity, and metabolic syndrome. Prospective animal studies with individual and limited EC mixtures support these observations and provide a means to investigate underlying physiological and molecular mechanisms. The greatest impacts of EC exposure are through programming of the developing embryo and/or fetus, with additional placental effects reported in eutherian mammals. Single-chemical effects and mechanistic studies, including transgenerational epigenetic inheritance, have been undertaken in rodents. Important translational models of human exposure are provided by companion animals, due to a shared environment, and sheep exposed to anthropogenic chemical mixtures present in pastures treated with sewage sludge (biosolids). Future animal research should prioritize EC mixtures that extend beyond a single developmental stage and/or generation. This would provide a more representative platform to investigate genetic and underlying mechanisms that explain sexually dimorphic and individual effects that could facilitate mitigation strategies.

Preconception exposure to bisphenol A and its alternatives: Effects on female fecundity mediated by oxidative stress and ovarian reserve

BACKGROUND

Various 'Bisphenol A (BPA)-free' alternatives have emerged in numerous personal products in recent years. However, it remains unclear whether BPA analogs affect female fecundity and possible biological mechanisms.

OBJECTIVES

We aimed to evaluate the relationships of bisphenol analogs with female fecundability and infertility and whether oxidative stress, inflammation, and ovarian reserve may play a mediation role in such associations.

METHODS

This prospective preconception cohort study included 957 couples who attempted pregnancy. BPA and six alternatives were measured in women's urine samples. Bisphenol analogs-outcome associations were estimated using discrete-time Cox hazards and logistic regression models. A quantile g-computation (QGC) methodology was further applied to assess the joint effects of co-exposure to bisphenol analogs on fecundity. We also quantified three biomarkers, including malondialdehyde (MDA), C-reactive protein and Anti-Müllerian hormone (AMH), to explore possible biological pathways.

RESULTS

Using an integrated analytical approach consisting of both single-pollutant and mixture models, we found that BPA and bisphenol AP (BPAP) were significantly associated with decreased fecundability (adjusted fecundability ratio (aFR) = 0.87, 95%CI: 0.81, 0.94 for BPA; aFR = 0.64, 95%CI: 0.48, 0.84 for BPAP) and increased risk of infertility (adjusted odd ratio (aOR) = 1.23, 95%CI: 1.06, 1.44 for BPA; aOR = 2.27, 95%CI: 1.29, 3.99 for BPAP) after controlling for other bisphenol analogs. The link between BPA and prolonged time to pregnancy was more prominent in overweight or obese women and those who had regular menstrual cycles. Bisphenol AF was associated with impaired fecundity in women aged 35 years or older. The mixed effects of bisphenol analogs on fecundity were statistically non-significant. Mediation analysis revealed a significant indirect effect of urinary MDA and serum AMH in bisphenol analogs-induced impaired fecundity, with all average causal mediation effects (ACME) showing statistical significance (PACME < 0.05).

CONCLUSIONS

Our prospective preconception cohort study suggests that BPA and BPAP may be associated with impaired female fecundity. Increased oxidative stress and decreased ovarian reserve may be the underlying pathways.

The impact of Bisphenol-A on human reproductive health

Bisphenol-A (BPA) is a recognized endocrine-disrupting chemical used to produce several consumer goods and products. There has been widespread exposure to BPA because of increased industrial production and use of BPA-containing products. As a result of these exposures, BPA is found in several human body fluids and can cause endocrine disruption by interfering with hormone signaling pathways and epigenetic modifications. Therefore, human reproductive health and development have been adversely affected by BPA. This review aimed to consolidate existing knowledge on the impact of BPA on human reproductive health, examining its effects on both males and females. To achieve this, we systematically searched four databases for studies that associated BPA with reproductive health (male and female), after which we retrieved the important information from the selected articles. There was an association of reproductive health diseases with high BPA exposure. In males, BPA was associated with increased sperm alterations, altered reproductive hormone levels, and testicular atrophy. In females, there was an association of BPA exposure with hormonal imbalances, reduced ovarian reserve, and increased likelihood of conditions such as fibroids, polycystic ovarian syndrome, endometriosis and infertility. BPA's pervasive presence and its harmful effects on reproductive health underscore the need for global regulation and public awareness. Although substantial evidence from animal and in vitro studies supports the detrimental effects of BPA, there is a need for more human-focused research, particularly in developing countries, to confirm these findings. This review advocates for increased regulatory measures to limit BPA exposure.

Sex and obesity influence the relationship between perfluoroalkyl substances and lean body mass: NHANES 2011-2018

Objective

Polyfluoroalkyl substances (PFAS) are known endocrine disruptors, that have been the subject of limited research regarding their impact on human lean body mass. The aim of this study was to investigate the effects of PFAS exposure on lean body mass.

Methods

We performed a cross-sectional data analysis involving 1022 adolescents and 3274 adults from the National Health and Nutrition Examination Survey (NHANES) 2011-2018, whose lean body mass was measured by dual-energy X-ray absorptiometry. The lean mass index (LMI) was calculated as lean body mass dividing by the square of height. The association between PFAS and LMI was examined through a multivariate-adjusted weighted generalized linear model. Moreover, weighted quantile sum (WQS) regression models were employed to futher examine the relationship between the mixture of PFAS and LMI.

Results

Regression analyses revealed an inverse correlation between PFAS exposure and LMI after adjusting for potential covariates. Adults with higher serum PFAS concentrations manifested a reduction in whole LMI ( β  = -0.193, 95 % confidence interval (CI): -0.325 to -0.06). Notably, this correlation was particularly significant in adult females and individuals with obesity, and it was observed across diverse anatomical regions, including lower limbs, right arm, trunk, and whole lean body mass. In adult females, the association between PFAS and whole LMI was statistically significant ( β  = -0.294, 95 % CI: -0.495 to -0.094), and a similar trend was found in obese individuals ( β  = -0.512, 95 % CI: -0.762 to -0.261). WQS regression analyses supported the results obtained from weighted linear regression analyses.

Conclusions

Our study suggests that exposure to PFAS, whether individually or in combination, is associated with decreased lean body mass in specific body areas, with sex and obesity serving as major influencing factors.

Climate change, microplastics, and male infertility

PURPOSE OF REVIEW

Semen quality is on the decline. While the etiology is unknown, recent literature suggests there may be a relationship between climate change, environmental toxins and male fertility. This review relays new information regarding associations between our environment and male infertility.

RECENT FINDINGS

Several recent studies have documented a negative association between heat stress and spermatogenesis, which suggests that climate change may be a factor in declining in sperm counts. The influence of particle pollution on spermatogenesis has also been recently investigated, with studies demonstrating a negative association. Another possible factor are microplastics, which have been posited to reduce sperm production. Recent animal studies have shown that microplastic exposure alters both adult sperm production and prenatal male genital development. The relationship between endocrine disrupting chemicals and male fertility remains an area of active study, with recent animal and human studies suggesting an association between these chemicals and male fertility.

SUMMARY

The etiology of the decline in male fertility over the past decades is yet unknown. However, changes in our environment as seen with climate change and exposure to pollutants and endocrine disrupting chemicals are proposed mechanisms for this decline. Further studies are needed to investigate this association further.

A metabolomic perspective on the mechanisms by which environmental pollutants and lifestyle lead to male infertility

The incidence of male infertility (MI) is rising annually. According to epidemiological studies, environmental pollution (e.g., organic, inorganic, and air pollutants), occupational exposure (e.g., high temperature, organic solvents, and pesticides), and poor lifestyle (e.g., diet, sleep, smoking, alcohol consumption, and exercise) are important non-genetic causative factors of MI. Due to multiple and complex causative factors, the dose-effect relationship, and the uncertainty of pathogenicity, the pathogenesis of MI is far from fully clarified. Recent data show that the pathogenesis of MI can be monitored by the metabolites in serum, seminal plasma, urine, testicular tissue, sperm, and other biological samples. It is considered that these metabolites are closely related to MI phenotypes and can directly reflect the individual pathological and physiological conditions. Therefore, qualitative and quantitative analysis of the metabolome, the related metabolic pathways, and the identification of biomarkers will help to explore the MI-related metabolic problems and provide valuable insights into its pathogenic mechanisms. Here, we summarized new findings in MI metabolomics biomarkers research and their abnormal metabolic pathways triggered by the presented non-genetic risk factors, providing a metabolic landscape of semen and seminal plasma in general MI patients. Then, we compared the similarities and differences in semen and seminal plasma biomarkers between MI patients exposed to environmental and poor lifestyle factors and MI patients in general, and summarized some common biomarkers. We provide a better understanding of the biological underpinnings of MI pathogenesis, which might offer novel diagnostic, prognostic, and precise treatment approaches to MI.

Cross sectional study on exposure to BPA and its analogues and semen parameters in Czech men

Exposure to bisphenols has been found to have adverse effects on male reproductive function in animals. Human exposure to bisphenols is widespread. Bisphenol A (BPA) and its analogues, including bisphenol S (BPS), bisphenol F (BPF), and bisphenol AF (BPAF) are utilized in various consumer products such as food contact materials and dental resins. The effects of these compounds on male fertility and spermatogenesis are unclear and findings from human studies are inconsistent. In this cross-sectional study, we evaluated the influence of BPA, BPS, BPF, BPAF (BPs) measured in semen on number of spermatozoa, total motility, progressive motility, morphology, and DNA fragmentation. We also examined the association of bisphenols (BPs) exposure with patients' occupation. A total of 358 patients aged 17-62 years with BMI 18-42 were included in the study from 2019 to 2021. BPs were extracted using solvent extraction followed by preconcentration step and determined by high-performance liquid chromatography and tandem mass spectrometry (LC/MSMS). Bisphenols were detected in 343 from 349 analysed samples (98.3% of all the samples). In 6 samples, the concentration of all BPs was under the limit of detection and in 20 samples under the limit of quantification. We did not find a statistically significant relationship between occupation and BPs. However, we observed significant correlations between the concentration of BPA and a lower motility and normal morphology. For BPS, a significant correlation with a lower ejaculate volume and a lower total sperm count was found. BPF and BPAF were detected only in 14.3% and 23.9% of samples, respectively. For BPF and BPAF, no significant correlations with spermiogram parameters were observed. Our results show that BPs are widespread in the male population (more than 90% of analysed samples), independently of an occupation and in case of BPA and BPS having a negative impact on spermiogram parameters.

Endocrine disrupting chemicals and their effects on the reproductive health in men

Endocrine Disrupting Chemicals (EDCs) are harmful compounds that enter the environment naturally or through anthropogenic activities and disrupt normal endocrine functions in humans, adversely affecting reproductive health. Among the most significant sources of EDC contaminants are the pharmaceutical, cosmetic, and packaging industries. EDCs have been identified to have a deteriorating effect on male reproductive system, as evidenced by the increasing number of male infertility cases. A large number of case studies have been published in which men exposed to EDCs experienced testicular cancer, undescended testicles, a decrease in serum testosterone levels, and poor semen quality. Furthermore, epidemiological evidence suggested a link between prenatal EDC exposure and cryptorchidism or undescended testicles, hypospadias, and decreased anogenital distance in infants. The majority of these findings, however, are incongruent due to the lack of long-term follow-up studies that would demonstrate EDCs to be associated with male reproductive disorders. This review aims to provide an overview on recent scientific progress on the association of EDCs to male reproductive health with special emphasis on its toxicity and possible mechanism of EDCs that disrupt male reproductive system.

The Effects of Bisphenol A on Human Male Infertility: A Review of Current Epidemiological Studies

Endocrine disruptor chemicals (EDCs) can have a harmful effect on the human body's endocrine system and thus adversely affect the development, reproduction, neurological, cardiovascular, and immune systems and metabolism in humans and wildlife. According to the World Health Organization, EDCs are mostly man-made and found ubiquitously in our daily lives, notably in pesticides, metals, and additives or contaminants in food and personal care products. Human exposure occurs through ingestion, inhalation, and dermal contact. Bisphenol A (BPA) is a proven EDC capable of mimicking or blocking receptors and altering hormone concentrations and metabolism. Although consumed in low doses, it can stimulate cellular responses and affect the body's functions. In humans, exposure to BPA has been correlated with the onset or development of several diseases. This literature review aimed to verify the effects of BPA on human male infertility using the most recently published literature. Thus, this review allowed us to conclude that this compound seems to have harmful effects on human male fertility, causing changes in hormonal and semen characteristics. However, these conclusions lack more robust and reproducible scientific studies. Even so, and since male infertility prevalence is increasing, preventive measures must be taken to ensure male fertility.

In vivo effects of low dose prenatal bisphenol A exposure on adiposity in male and female ICR offspring

BACKGROUND

Bisphenol A (BPA) is known to exhibit endocrine disrupting activities and is associated with adiposity. We examined the obesogenic effect of prenatal BPA exposure in the present study.

METHODS

Pregnant ICR mice were exposed to vehicle or BPA via the drinking water at a dose of 0.5 μg/kg·d throughout the gestation. Obesity-related indexes were investigated in the 12-wk-old offspring. Primary mouse embryonic fibroblasts (MEFs) collected from treated embryos were used to test effects of BPA on adipocyte differentiation.

RESULTS

Offspring presented a significantly higher rate of weight gain than the control, with impaired insulin sensitivity and increased adipocyte size. Differentiation of MEFs from BPA-treated mice showed a higher propensity for the adipocyte commitment as well as up-regulation of genes enriched in lipid biosynthesis. TGF-β signaling pathway was found to modulate obesogenic effect of BPA in MEF model, but estrogen signaling pathway had no effect.

CONCLUSIONS

The present study provides strong evidence of the association between prenatal exposure to low dose of BPA and a significant increase in body weight in the offspring mice with a critical role played by TGF-β signaling pathway. The potential interactions modulating the binding of BPA and TGF-β that activate its obesogenic effects need to be examined.

Temporal decline of sperm concentration: role of endocrine disruptors

INTRODUCTION

Male infertility is a widespread disease with an etiology that is not always clear. A number of studies have reported a decrease in sperm production in the last forty years. Although the reasons are still undefined, the change in environmental conditions and the higher exposure to endocrine-disrupting chemicals (EDCs), namely bisphenol A, phthalates, polychlorinated biphenyls, polybrominated diphenyl esters, dichlorodiphenyl-dichloroethylene, pesticides, and herbicides, organophosphates, and heavy metals, starting from prenatal life may represent a possible factor justifying the temporal decline in sperm count.

AIM

The aim of this study is to provide a comprehensive description of the effects of the exposure to EDCs on testicular development, spermatogenesis, the prevalence of malformations of the male genital tract (cryptorchidism, testicular dysgenesis, and hypospadias), testicular tumor, and the mechanisms of testicular EDC-mediated damage.

NARRATIVE REVIEW

Animal studies confirm the deleterious impact of EDCs on the male reproductive apparatus. EDCs can compromise male fertility by binding to hormone receptors, dysregulating the expression of receptors, disrupting steroidogenesis and hormonal metabolism, and altering the epigenetic mechanisms. In humans, exposure to EDCs has been associated with poor semen quality, increased sperm DNA fragmentation, increased gonadotropin levels, a slightly increased risk of structural abnormalities of the genital apparatus, such as cryptorchidism and hypospadias, and development of testicular tumor. Finally, maternal exposure to EDCs seems to predispose to the risk of developing testicular tumors.

CONCLUSION

EDCs negatively impact the testicular function, as suggested by evidence in both experimental animals and humans. A prenatal and postnatal increase to EDC exposure compared to the past may likely represent one of the factors leading to the temporal decline in sperm counts.

Effects of thiram exposure on liver metabolism of chickens

Pesticides are widely used to control crop diseases, which have made an important contribution to the increase of global crop production. However, a considerable part of pesticides may remain in plants, posing a huge threat to animal safety. Thiram is a common pesticide and has been proven that its residues in the feed can affect the growth performance, bone formation, and intestinal health of chickens. However, there are few studies on the liver metabolism of chickens exposed to thiram. Here, the present study was conducted to investigate the effect of thiram exposure on liver metabolism of chickens. Metabolomics analysis shows that 62 metabolites were down-regulated (ginsenoside F5, arbekacin, coproporphyrinogen III, 3-keto Fusidic acid, marmesin, isofumonisin B1, 3-Hydroxyquinine, melleolide B, naphazoline, marmesin, dibenzyl ether, etc.) and 35 metabolites were up-regulated (tetrabromodiphenyl ethers, deoxycholic acid glycine conjugate, L-Palmitoylcarnitine, austalide K, hericene B, pentadecanoylcarnitine, glyceryl palmitostearate, quinestrol, 7-Ketocholesterol, tetrabromodiphenyl ethers, etc.) in thiram-induced chickens, mainly involved in the metabolic pathways including glycosylphosphatidylinositol (GPI)-anchor biosynthesis, porphyrin and chlorophyll metabolism, glycerophospholipid metabolism, primary bile acid biosynthesis and steroid hormone biosynthesis. Taken together, this research showed that thiram exposure significantly altered hepatic metabolism in chickens. Moreover, this study also provided a basis for regulating the use and disposal of thiram to ensure environmental quality and poultry health.

Gut microbiota and acylcarnitine metabolites connect the beneficial association between equol and adiposity in adults: a prospective cohort study

BACKGROUND

Many studies have investigated the effects of soy isoflavones on weight control, but few have focused on the role of equol, a gut-derived metabolite of daidzein with greater bioavailability than other soy isoflavones.

OBJECTIVES

This study examined the association of equol production with obesity and explored the mediating roles of equol-related gut microbiota and microbial carnitine metabolites.

METHODS

This 6.6-y prospective study included 2958 Chinese adults (2011 females and 947 males) aged 60.6 ± 6.0 y (mean ± SD) at baseline. Urinary equol and isoflavones were measured using HPLC-tandem MS. BMI, percentage fat mass (%FM), and serum triglycerides (TGs) were assessed every 3 y. Metagenomics sequencing and assessment of carnitine metabolites in feces were performed in a subsample of 897 participants.

RESULTS

Urinary equol, but not daidzein and genistein, was independently and inversely associated with the obesity-related indicators of BMI, %FM, and a biomarker (TGs). Equol producers (EPs) had lower odds of adiposity conditions and a reduced risk of 6.6-y obesity progression than non-EPs among total participants. Gut microbial analyses indicated that EPs had higher microbiome species richness (P = 3.42 × 10-5) and significantly different β-diversity of gut microbiota compared with the non-EP group (P = 0.001), with 20 of 162 species differing significantly. EPs (compared with non-EPs) had higher abundances of Alistipes senegalensis and Coprococcus catus but lower abundances of Ruminococcus gnavus (false discovery rate <0.05). Among the 7 determined fecal acylcarnitine metabolites, palmitoylcarnitine, oleylcarnitine 18:1, and stearylcarnitine were inversely associated with EPs but positively correlated with obesity conditions and progression. Path analyses indicated that the beneficial association between equol and obesity might be mediated by gut microbiota and decreased production of 3 acylcarnitines in feces.

CONCLUSIONS

This study suggests a beneficial association between equol and obesity, mediated by the gut microbiome and acylcarnitines, in adults.This trial was registered at clinicaltrials.gov as NCT03179657.

Environmental metal exposure, seminal plasma metabolome and semen quality: Evidence from Chinese reproductive-aged men

Environmental metal exposure has been associated with decreasing semen quality, but the effects of multiple metal exposure on seminal plasma metabolome remain obscure. In this study, semen and repeated urine samples from 551 volunteers were collected in Wuhan City. Heavy metals and trace elements were measured using inductively coupled plasma mass spectrometer, and seminal plasma metabolomes were acquired using liquid chromatography coupled with high-resolution mass spectrometry. Weighted gene co-expression network analysis showed more than half of the seminal plasma metals were associated with specific metabolite modules, whereas only a few urine metals presented weak associations, indicating that seminal plasma may be an ideal biological sample for male reproductive biomarker discovery and exposure risk assessment. Seminal plasma zinc (Zn) and selenium (Se) concentrations were significantly associated with 22 metabolites (e.g., glycerophospholipids, acyl-carnitines and amino acid derivatives). Among these metabolites, acyl-carnitines were positively associated with semen quality and sperm concentration. Moreover, acyl-carnitines were associated with both Zn and Se exposure, indicating the potential role of carnitine pathway in their toxicity mechanism. Our findings suggest that seminal plasma metabolome connects Zn and Se exposure and sperm concentrations in Chinese men of reproductive age.

From Oxidative Stress to Male Infertility: Review of the Associations of Endocrine-Disrupting Chemicals (Bisphenols, Phthalates, and Parabens) with Human Semen Quality

Exposure to endocrine-disrupting chemicals (EDCs) may result in oxidative stress and endocrine system disturbance, which can have an impact on human reproduction and development. In male reproductive health, EDCs have been related to impaired reproductive function and male infertility, altered fetal development, and testicular germ-cell, prostate, and breast cancers. We conducted an electronic search using PubMed on endocrine disruptors related to oxidative stress and male infertility, and evaluated their association with endocrine-disrupting chemicals (bisphenols, phthalates, and parabens) in 25 articles. Higher levels of urinary bisphenols showed correlation with impaired semen quality and increased DNA damage. Considering phthalates and their metabolites, all studies found a positive association between urinary levels of phthalates and at least one semen parameter indicative of low semen quality; some studies also revealed sperm DNA damage. The studies on parabens less often revealed correlation of urinary parabens concentrations with a decrease in sperm count, as well as motility and DNA damage. Moreover, EDCs can elevate ROS production and lipid peroxidation, increase apoptosis, induce epigenetic modifications, and change the Y:X sperm chromosome ratio and sperm protein composition. Our review revealed detrimental effects of EDCs on semen quality and sperm DNA integrity-especially in BPA and phthalates, but also in parabens.

High-fat diet aggravates prenatal low-dose DEHP exposure induced spermatogenesis disorder: Characterization of testicular metabolic patterns in mouse offspring

Di-(2-ethylhexyl) phthalate (DEHP) is a widely used plasticizer and has been identified as a male prenatal reproductive toxicant. A high fat diet (HFD) has also been suggested as another potential disruptor of male reproductive function. Despite this potential synergism between DEHP exposure and HFD, little is known about the concomitant effects of prenatal DEHP and a subsequent HFD exposure on male offspring reproductive injury. Here we established a mouse model of prenatal exposure to DEHP (0.2 mg/kg/day) to assess the testicular development and spermatogenesis in offspring subjected to obesogenic diet during the pubertal period. Gross phenotype, hormone profiles and the testicular metabolome were analyzed to determine the underlying mechanism. We found that prenatal exposure to low-dose DEHP resulted in decreased sperm density, decreased testosterone (T) levels, increased luteinizing hormone (LH) levels and testicular germ cell apoptosis. Furthermore, these injury phenotypes were aggravated by pubertal HFD treatment. Testicular riboflavin and biotin metabolites were enriched implying their roles in contributing HFD to exacerbate offspring spermatogenesis disorders due to prenatal low-dose DEHP exposure. Our findings suggest that pubertal HFD exacerbates reproductive dysfunction associated with prenatal exposure to low-dose DEHP in male adult offspring.

Progress in modern reproductive biology research in China

Reproductive biology is closely associated with human health and social progress. Modern reproductive biology research in China began in the 1930s. Advances in science, technology, government support and international collaborations spawned the rapid growth of reproductive biology research in China. While the development of reproductive biology has provided both theoretical knowledge and applicable technologies, it has also generated new social and ethical concerns. This review summarizes and highlights the contributions of modern reproductive biology research in China, with a specific focus on aspects that are most related to human reproduction and health.

Environmental and occupational exposures associated with male infertility

The upsurge in male infertility over the last two decades, possibly due to environmental exposure, has raised significant interest, particularly boosted by reports from fertility clinics, which showed that chronic diseases and hereditary or other medical conditions might only partially explain current incidence of male infertility. Both environmental and occupational settings may have a significant role in exposure to complex mixtures of endocrine disruptors (ED), which play a major role in fertility disorders. The aim of this review is to give an insight into the current knowledge on exposure settings which may be associated with male infertility. Our study relied on a systematic search of PubMed, Scopus, and Web of Science for articles published between January 2000 and September 2020. It showed that some well documented factors associated with male infertility include smoking, and physiological disturbances or chronic diseases such as obesity and diabetes, which in turn, may also reflect lifestyle choices and environmental exposures, especially to EDs such as phthalates, bisphenols, pesticides, and flame retardants. However, the number of studies on the aetiology of male infertility is still too low in comparison with the size of affected population. Occupational health follow-ups and medical surveillance do not collect any data on male infertility, even though ED chemicals are part of many technological processes.

An exposomic approach with 138 chemical and non-chemical exposures to predict 32 biomarkers of male reproductive damages: A case study of college students in Chongqing, China

Male reproductive damage in the general population comprises different disorders in various biomarkers, which could be respectively caused by a number of exposure factors. However, researchers considering the environmental/behavioral/psychological exposures together to evaluate their contribution to male reproductive damage are still lacking. The present study investigated the comprehensive association between 138 environmental/behavioral/psychological exposures and 32 male reproductive biomarkers in 796 young Chinese men using graph-guided fused lasso (GFLASSO) and hierarchical clustering methods. All biomarkers were found to be associated with various exposures. A combination of these exposures not only predicted the levels of single biomarkers in another test dataset, but also identified the comprehensive reproductive features by clustering the men into five subgroups with distinct damages representing disrupted spermatogenesis with abnormal sperm morphology, low sperm motility with DNA fragmentation, chromatin immaturity, aberrant endocrine, or DNA strand breakage. The findings can be used to suggest a novel way to identify the males with a high risk of reproductive damage and develop personalized preventive strategies.

Endocrine disrupting chemicals: Impacts on human fertility and fecundity during the peri-conception period

It is becoming increasingly difficult to avoid exposure to man-made endocrine disrupting chemicals (EDCs) and environmental toxicants. This escalating yet constant exposure is postulated to partially explain the concurrent decline in human fertility that has occurred over the last 50 years. Controversy however remains as to whether associations exist, with conflicting findings commonly reported for all major EDC classes. The primary aim of this extensive work was to identify and review strong peer-reviewed evidence regarding the effects of environmentally-relevant EDC concentrations on adult male and female fertility during the critical periconception period on reproductive hormone concentrations, gamete and embryo characteristics, as well as the time to pregnancy in the general population. Secondly, to ascertain whether individuals or couples diagnosed as sub-fertile exhibit higher EDC or toxicant concentrations. Lastly, to highlight where little or no data exists that prevents strong associations being identified. From the greater than 1480 known EDCs, substantial evidence supports a negative association between exposure to phthalates, PCBs, PBDEs, pyrethroids, organochloride pesticides and male fertility and fecundity. Only moderate evidence exists for a negative association between BPA, PCBs, organochloride pesticides and female fertility and fecundity. Overall fewer studies were reported in women than men, with knowledge gaps generally evident for both sexes for all the major EDC classes, as well as a paucity of female fertility studies following exposure to parabens, triclosans, dioxins, PFAS, organophosphates and pyrethroids. Generally, sub-fertile individuals or couples exhibit higher EDC concentrations, endorsing a positive association between EDC exposure and sub-fertility. This review also discusses confounding and limiting factors that hamper our understanding of EDC exposures on fertility and fecundity. Finally, it highlights future research areas, as well as government, industry and social awareness strategies required to mitigate the negative effects of EDC and environmental toxicant exposure on human fertility and fecundity.

Metabolomics analysis reveals metabolic changes associated with trans-resveratrol treatment in experimental cryptorchidism mice

This study aimed to analyse global metabolomic changes associated with trans-resveratrol (RSV) treatment in mice with cryptorchidism using untargeted metabolomics. Cryptorchidism was established surgically in Kunming mice, which were then treated with 20µg g-1 day-1, s.c., RSV for 35 consecutive days. Typical manifestations of spermatogenesis arrest were seen in mice with cryptorchidism, and RSV treatment for 35 days restored spermatogenesis. Liquid chromatography-tandem mass spectrometry was used to profile the metabolome of testes from mice in the control (non-cryptorchid, untreated), cryptorchid and RSV-treated cryptorchid groups. In all, 1386 and 179 differential metabolites were detected in the positive and negative modes respectively. Seven and six potential biomarkers were screened for spermatogenesis arrest and restoration respectively. Pathway analysis showed changes in 197 metabolic pathways. The hexosamine biosynthesis pathway was inhibited in the cryptorchid group, which probably resulted in a decrease in the end product, uridine diphosphate N-acetylglucosamine (UDP-GlcNAc). Immunoblot analysis showed that total testicular protein O-linked β-N-acetylglucosamine glycosylation was related to spermatogenesis arrest, further indicating a decrease in UDP-GlcNAc in the cryptorchid group. Thus, untargeted metabolomics revealed the biochemical pathways associated with the restoration of metabolic status in the cryptorchid group following RSV treatment and the findings could be used to monitor the response to RSV treatment. This study provides a meaningful foundation for the future clinical application of RSV in the treatment of spermatogenesis dysfunction.

[Effects of bisphenol A on apoptosis of ovarian preantral follicular granulosa cells and ovarian development in mice]

OBJECTIVE

To investigate the effect of environmental estrogen bisphenol A (BPA) exposure on apoptosis of mouse ovarian preantral follicular granulosa cells and ovarian development and explore the underlying mechanism.

METHODS

Mouse ovarian preantral follicular granulosa cells were isolated from female ICR mice at postnatal day (PND) 10 and cultured in vitro. The cultured cells were treated with 0, 1, 10, 50, 100, 150, 200 and 500 μmol/L BPA, and the changes in cell proliferation, cell cycle, apoptosis and mitochondrial membrane potential were analyzed with CCK-8 method and flow cytometry. The protein expressions of Bcl-2, Bax, p53 and cyclin D1 in the treated cells were determined with Western blotting. Pregnant ICR mice were treated for a week with BPA at the concentration that produced significant effects on the preantral follicular granulosa cells, and the weight changes of the pregnant mice were recorded. The ovarian tissues of the offspring female mice were weighed at PND 10, 17, 21 and 42 followed by histological observation with HE staining and examination of Bcl-2 mRNA expression level with RT-qPCR.

RESULTS

Compared with the control cells group, the isolated cells exposed to a low concentration of BPA (50 μmol/L) showed a significantly lowered apoptosis rate, increased mitochondrial membrane potential, and enhanced cellular proliferation (P < 0.05). Exposure to a higher BPA concentration at 200 μmol/L obviously enhanced cell apoptosis by reducing the mitochondrial membrane potential and repressed the cell proliferation (P < 0.05). BPA exposure at 50 μmol/L and 200 μmol/L produced opposite effects on the protein expressions of Bcl-2 (P < 0.01), Bax (P < 0.05) and p53 (P < 0.05) in mouse ovarian preantral follicular granulosa cells. BPA exposure at the doses of 10 and 35 mg/kg caused rapid weight increment of the pregnant mice and changes in ovarian index of the offspring female mice. In the offspring female mice, the changes in Bcl-2 mRNA expression in the ovarian tissue showed a similar pattern to that of ovarian index. Exposure of the pregnant mice to a high BPA concentration at 35 mg/kg resulted in accelerated follicular development into antral follicular stage in PND 21 offspring female mice.

CONCLUSIONS

BPA can concentration-dependently regulate the function of ovarian preantral follicular granulosa cells in mice and potentially affects both the pregnant mice and the offspring female mice in light of early ovarian development.

The influence of different polymer types of microplastics on adsorption, accumulation, and toxicity of triclosan in zebrafish

Although the combined effects of microplastics (MPs) and other organic pollutants have raised increasing attention, the impacts of polymer types on the biological effects (e.g., bioaccumulation and toxicity) of the mixtures are still unclear. This study aimed to evaluate the influence of different polymer types of MPs including polyethylene (PE), polypropylene (PP), and polyvinyl chloride (PVC) on the adsorption, accumulation, and toxic effects of triclosan (TCS) in zebrafish. As a result, all three types of MPs could adsorb TCS and PP-MPs has the highest adsorption capacity for TCS (1.18 mg/g). Compared with the TCS alone, MPs changed the distribution of TCS in tissues and increased the accumulation of TCS in the liver and gut following the order of TCS + PP > TCS + PVC > TCS + PE. Compared with individual TCS and PP-MPs, after co-exposed for 28 days, TCS + PP significantly aggravated oxidative stress and lipid peroxidation in the liver as well as enhanced neurotoxicity in the brain. Moreover, TCS + PP disturbed the metabolism in the liver and MPs contributed more to the metabolic disorders. The upregulated lipid metabolites (e.g., sphingosine and L-palmitoylcarnitine) and downregulated carbohydrate metabolites (e.g., sucrose) could be potential targets for future risk assessment of MPs combined with other pollutants.

Photochemical reaction kinetics and mechanism of bisphenol A with K2S2O8 in aqueous solution: a laser flash photolysis study

The photochemical reaction kinetics and mechanism of bisphenol A (BPA) with potassium persulfate (K2S2O8) were investigated by using 266 nm laser flash photolysis and gas chromatography mass spectrum (GC-MS) technique. Sulfate radical (SO4•−), generated upon K2S2O8 photolysis, reacted with BPA with the overall rate constant of (1.61 ± 0.15) × 109 L mol−1 s−1, and two main reaction mechanisms were involved. One was addition channel to generate BPA–SO4•− adduct with a specific second-order rate constant of (1.09 ± 0.15) × 109 L mol−1 s−1. Molecular oxygen was involved in the decay of the BPA–SO4•− adduct with a rate constant of (1.28 ± 0.14) × 108 L mol−1 s−1. Another channel was the formation of BPA’s phenoxyl radical, likely derived from a deprotonation of the cation radical (BPA•+) generated from single electron transfer reactions. The specific rate constant of BPA’s phenoxyl radical formation was determined to be (6.16 ± 0.08) × 108 L mol−1 s−1. The overall rate constant was in line with the sum of aforementioned two specific rate constants for two main reaction channels. By comparing these rate constants, it was indicated that SO4•− addition channel accounted for ∼65% (1.09/1.61) to the overall reaction, and phenoxyl radical formation accounted for only ∼35% (0.62/1.61). The transformation products of BPA were identified by using GC-MS including 4-isopropylphenol, 4-isopropenylphenol, and 2,4-di-tert-butylphenol, and the reaction mechanism was proposed. These results may provide microscopic kinetics and mechanism information on BPA degradation using SO4•−-based advanced oxidation processes.

Endocrine Disrupting Chemicals and Reproductive Health in Boys and Men

Male reproductive health has declined as indicated by increasing rates of cryptorchidism, i.e., undescended testis, poor semen quality, low serum testosterone level, and testicular cancer. Exposure to endocrine disrupting chemicals (EDCs) has been proposed to have a role in this finding. In utero exposure to antiandrogenic EDCs, particularly at a sensitive period of fetal testicular development, the so-called 'masculinization programming window (MPW)', can disturb testicular development and function. Low androgen effect during the MPW can cause both short- and long-term reproductive disorders. A concurrent exposure to EDCs may also affect testicular function or damage testicular cells. Evidence from animal studies supports the role of endocrine disrupting chemicals in development of male reproductive disorders. However, evidence from epidemiological studies is relatively mixed. In this article, we review the current literature that evaluated relationship between prenatal EDC exposures and anogenital distance, cryptorchidism, and congenital penile abnormality called hypospadias. We review also studies on the association between early life and postnatal EDC exposure and semen quality, hypothalamic-pituitary-gonadal axis hormone levels and testicular cancer.

Regional difference in semen quality of young men: a review on the implication of environmental and lifestyle factors during fetal life and adulthood

The prevalence of low semen quality and the incidence of testicular cancer have been steadily increasing over the past decades in different parts of the World. Although these conditions may have a genetic or epigenetic origin, there is growing evidence that multiple environmental and lifestyle factors can act alone or in combination to induce adverse effects. Exposure to these factors may occur as early as during fetal life, via the mother, and directly throughout adulthood after full spermatogenic capacity is reached. This review aims at providing an overview of past and current trends in semen quality and its relevance to fertility as well as a barometer of men’s general health. The focus will be on recent epidemiological studies of young men from the general population highlighting geographic variations in Europe. The impact of some lifestyle and environmental factors will be discussed with their role in both fetal life and adulthood. These factors include smoking, alcohol consumption, psychological stress, exposure to electromagnetic radiation, and Endocrine Disrupting Chemicals (EDCs). Finally, the challenges in investigating the influence of environmental factors on semen quality in a fast changing world are presented.

Endocrine-disrupting chemicals and male reproductive health

BACKGROUND

A number of different types of endocrine-disrupting chemicals (EDCs) including bisphenol A, phthalates, pesticides, and other environmental chemicals have been shown to adversely impact upon male reproductive health. Understanding the potential effects of EDCs on male reproductive health may enable the development of novel treatments and early prevention of the effects of EDCs on male infertility and their potential long-term sequelae. This review critically evaluates the research performed in this area and explores potential harmful effects of EDCs in animals and humans, including the possibility of trans-generational transmission.

METHODS

A literature review was conducted using electronic databases using the following terms: 'endocrine disrupt*' OR 'endocrine disruptors' OR 'endocrine disruptor chemicals' OR 'EDC' AND 'sperm*' OR 'spermatozoa' OR 'spermatozoon' OR 'male reproductive health' OR' male fertility'.

MAIN FINDINGS

Several studies have shown that EDCs have a variety of pathophysiological effects. These include failure of spermatogenesis, embryonic development, the association with testicular cancer, and long-term metabolic effects.

CONCLUSIONS

Several studies observe correlations between chemical doses and at least one sperm parameter; however, such correlations are sometimes inconsistent between different studies. Mechanisms through which EDCs exert their pathophysiological effects have not yet been fully elucidated in human studies.

Metabolomics Reveals that Cysteine Metabolism Plays a Role in Celastrol-Induced Mitochondrial Apoptosis in HL-60 and NB-4 Cells

Recently, celastrol has shown great potential for inducing apoptosis in acute myeloid leukemia cells, especially acute promyelocytic leukaemia cells. However, the mechanism is poorly understood. Metabolomics provides an overall understanding of metabolic mechanisms to illustrate celastrol's mechanism of action. We treated both nude mice bearing HL-60 cell xenografts in vivo and HL-60 cells as well as NB-4 cells in vitro with celastrol. Ultra-performance liquid chromatography coupled with mass spectrometry was used for metabolomics analysis of HL-60 cells in vivo and for targeted L-cysteine analysis in HL-60 and NB-4 cells in vitro. Flow cytometric analysis was performed to assess mitochondrial membrane potential, reactive oxygen species and apoptosis. Western blotting was conducted to detect the p53, Bax, cleaved caspase 9 and cleaved caspase 3 proteins. Celastrol inhibited tumour growth, induced apoptosis, and upregulated pro-apoptotic proteins in the xenograft tumour mouse model. Metabolomics showed that cysteine metabolism was the key metabolic alteration after celastrol treatment in HL-60 cells in vivo. Celastrol decreased L-cysteine in HL-60 cells. Acetylcysteine supplementation reversed reactive oxygen species accumulation and apoptosis induced by celastrol and reversed the dramatic decrease in the mitochondrial membrane potential and upregulation of pro-apoptotic proteins in HL-60 cells. In NB-4 cells, celastrol decreased L-cysteine, and acetylcysteine reversed celastrol-induced reactive oxygen species accumulation and apoptosis. We are the first to identify the involvement of a cysteine metabolism/reactive oxygen species/p53/Bax/caspase 9/caspase 3 pathway in celastrol-triggered mitochondrial apoptosis in HL-60 and NB-4 cells, providing a novel underlying mechanism through which celastrol could be used to treat acute myeloid leukaemia, especially acute promyelocytic leukaemia.

Systematic Analysis of Impact of Sampling Regions and Storage Methods on Fecal Gut Microbiome and Metabolome Profiles

The contribution of human gastrointestinal (GI) microbiota and metabolites to host health has recently become much clearer. However, many confounding factors can influence the accuracy of gut microbiome and metabolome studies, resulting in inconsistencies in published results. In this study, we systematically investigated the effects of fecal sampling regions and storage and retrieval conditions on gut microbiome and metabolite profiles from three healthy children. Our analysis indicated that compared to homogenized and snap-frozen samples (standard control [SC]), different sampling regions did not affect microbial community alpha diversity, while a total of 22 of 176 identified metabolites varied significantly across different sampling regions. In contrast, storage conditions significantly influenced the microbiome and metabolome. Short-term room temperature storage had a minimal effect on the microbiome and metabolome profiles. Sample storage in RNALater showed a significant level of variation in both microbiome and metabolome profiles, independent of the storage or retrieval conditions. The effect of RNALater on the metabolome was stronger than the effect on the microbiome, and individual variability between study participants outweighed the effect of RNALater on the microbiome. We conclude that homogenizing stool samples was critical for metabolomic analysis but not necessary for microbiome analysis. Short-term room temperature storage had a minimal effect on the microbiome and metabolome profiles and is recommended for short-term fecal sample storage. In addition, our study indicates that the use of RNALater as a storage medium of stool samples for microbial and metabolomic analyses is not recommended.IMPORTANCE The gastrointestinal microbiome and metabolome can provide a new angle to understand the development of health and disease. Stool samples are most frequently used for large-scale cohort studies. Standardized procedures for stool sample handling and storage can be a determining factor for performing microbiome or metabolome studies. In this study, we focused on the effects of stool sampling regions and stool sample storage conditions on variations in the gut microbiome composition and metabolome profile.

Systematic Analysis of Impact of Sampling Regions and Storage Methods on Fecal Gut Microbiome and Metabolome Profiles

The gastrointestinal microbiome and metabolome can provide a new angle to understand the development of health and disease. Stool samples are most frequently used for large-scale cohort studies. Standardized procedures for stool sample handling and storage can be a determining factor for performing microbiome or metabolome studies. In this study, we focused on the effects of stool sampling regions and stool sample storage conditions on variations in the gut microbiome composition and metabolome profile.

The contribution of human gastrointestinal (GI) microbiota and metabolites to host health has recently become much clearer. However, many confounding factors can influence the accuracy of gut microbiome and metabolome studies, resulting in inconsistencies in published results. In this study, we systematically investigated the effects of fecal sampling regions and storage and retrieval conditions on gut microbiome and metabolite profiles from three healthy children. Our analysis indicated that compared to homogenized and snap-frozen samples (standard control [SC]), different sampling regions did not affect microbial community alpha diversity, while a total of 22 of 176 identified metabolites varied significantly across different sampling regions. In contrast, storage conditions significantly influenced the microbiome and metabolome. Short-term room temperature storage had a minimal effect on the microbiome and metabolome profiles. Sample storage in RNALater showed a significant level of variation in both microbiome and metabolome profiles, independent of the storage or retrieval conditions. The effect of RNALater on the metabolome was stronger than the effect on the microbiome, and individual variability between study participants outweighed the effect of RNALater on the microbiome. We conclude that homogenizing stool samples was critical for metabolomic analysis but not necessary for microbiome analysis. Short-term room temperature storage had a minimal effect on the microbiome and metabolome profiles and is recommended for short-term fecal sample storage. In addition, our study indicates that the use of RNALater as a storage medium of stool samples for microbial and metabolomic analyses is not recommended.

IMPORTANCE The gastrointestinal microbiome and metabolome can provide a new angle to understand the development of health and disease. Stool samples are most frequently used for large-scale cohort studies. Standardized procedures for stool sample handling and storage can be a determining factor for performing microbiome or metabolome studies. In this study, we focused on the effects of stool sampling regions and stool sample storage conditions on variations in the gut microbiome composition and metabolome profile.

Metabolomic profiling identifies novel biomarkers and mechanisms in human bladder cancer treated with submucosal injection of gemcitabine

Bladder cancer (BCa) is a common urinary tract malignancy with frequent recurrences after initial resection. Submucosal injection of gemcitabine prior to transurethral resection of bladder tumor (TURBT) may prevent recurrence of urothelial cancer. However, the underlying mechanism remains unknown. In the present study, ultra-performance liquid chromatography Q-Exactive mass spectrometry was used to profile tissue metabolites from 12 BCa patients. The 48 samples included pre- and post-gemcitabine treatment BCa tissues, as well as adjacent normal tissues. Principal component analysis (PCA) revealed that the metabolic profiles of pre-gemcitabine BCa tissues differed significantly from those of pre-gemcitabine normal tissues. A total of 34 significantly altered metabolites were further analyzed. Pathway analysis using MetaboAnalyst identified three metabolic pathways closely associated with BCa, including glutathione, purine and thiamine metabolism, while gluta-thione metabolism was also identified by the enrichment analysis using MetaboAnalyst. In search of the possible targets of gemcitabine, metabolite profiles were compared between the pre-gemcitabine normal and post-gemcitabine BCa tissues. Among the 34 metabolites associated with BCa, the levels of bilirubin and retinal recovered in BCa tissues treated with gemcitabine. When comparing normal bladder tissues with and without gemcitabine treatment, among the 34 metabolites associated with BCa, it was observed that histamine change may be associated with the prevention of relapse, whereas thiamine change may be involved in possible side effects. Therefore, by employing a hypothesis-free tissue-based metabolomics study, the present study investigated the metabolic signatures of BCa and found that bilirubin and retinal may be involved in the mechanism underlying the biomolecular action of submucosal injection of gemcitabine in urothelial BCa.

Metabolomics reveals the role of acetyl-l-carnitine metabolism in γ-Fe2O3 NP-induced embryonic development toxicity via mitochondria damage

Iron oxides nanoparticles (FeOX NPs), including α-Fe2O3, γ-Fe2O3, and Fe3O4, are employed in many technological applications. However, very few studies have investigated the embryonic developmental toxicity of FeOX NPs. In this study, metabolomics analysis were used to uncover the potential mechanisms of FeOX NPs developmental toxicity on embryo-larval zebrafish and mice. Our results indicated that γ-Fe2O3 NP treatment could cause increased mortality, dropped hatching rate, etc., while α-Fe2O3 and Fe3O4 NPs showed no obvious effect. Through metabolomics analysis, a total of 42 metabolites were found to be significantly changed between the γ-Fe2O3 NP-treated group and the control group (p < 0.05). Pathway enrichment analysis indicated the impairment of mitochondria function. γ-Fe2O3 NP treatment caused abnormal mitochondrion structure and a decrease in mitochondrial membrane potential in zebrafish embryos. Meanwhile, ATP synthesis was decreased while oxidative stress levels were affected. It is noteworthy that acetyl-l-carnitine (ALCAR) (p = 6.79E - 04) and l-carnitine (p = 1.43E - 03) were identified with minimal p values, the relationship between the two counter-balance was regulated by acetyltransferase (crata). Subsequently, we performed rescue experiments with ALCAR on zebrafish embryos, and found that the mortality rates reduced and hatching rates raised significantly in the γ-Fe2O3 NP-treated group. Additionally, γ-Fe2O3 exposure could lead to increased absorbed fetus rate, decreased placental weight, lower expression of acetyltransferase (Crat), reduced ATP synthesis as well as increased oxidative stress (p < 0.05). Our findings demonstrated that γ-Fe2O3 NP might affect the mitochondrial membrane potential and ATP synthesis by affecting the metabolism of ALCAR, thereby stimulating oxidative stress, cell apoptosis, and causing embryonic development toxicity.

Metabolomics Reveals Metabolic Changes Caused by Low-Dose 4-Tert-Octylphenol in Mice Liver

Background: Humans are constantly exposed to low concentrations of 4-tert-octylphenol (OP). However, studies investigating the effects of low-dose OP on the liver are scarce, and the mechanism of these effects has not been thoroughly elucidated to date. Methods: Adult male institute of cancer research (ICR) mice were exposed to low-dose OP (0, 0.01 and 1 μg/kg/day) for 7 consecutive days. Weights of mice were recorded daily during the experiment. Blood serum levels of OP, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were determined, and haematoxylin-eosin (HE) staining of the liver was performed. We applied an integrated metabolomic and enzyme gene expression analysis to investigate liver metabolic changes, and the gene expression of related metabolic enzymes was determined by real-time PCR and ELISA. Results: OP in blood serum was increased after OP exposure, while body weights of mice were unchanged. Liver weight and its organ coefficient were decreased significantly in the OP (1 μg/kg/day) group, but ALT and AST, as well as the HE staining results, were unchanged after OP treatment. The levels of cytidine, uridine, purine and N-acetylglutamine were increased significantly, and the level of vitamin B6 was decreased significantly in mice treated with OP (1 μg/kg/day). The mRNA and protein levels of Cda and Shmt1 were both increased significantly in OP (1 μg/kg/day)-treated mice. Conclusions: Through metabolomic analysis, our study firstly found that pyrimidine and purine synthesis were promoted and that N-acetylglutamine was upregulated after low-dose OP treatment, indicating that the treatment disturbed nucleic acid and amino acid metabolism in mice liver.

Transcriptomics and metabonomics analyses of maternal DEHP exposure on male offspring

The objectives of this study were to evaluate the effect of maternal Di-2-ethylhexyl phthalate (DEHP) exposure on male offspring and to explore the mechanism of changes with the metabolic alterations and differential genes. Pregnant female Sprague-Dawley (SD) rats were intragastrically administered with 600 mg/kg body weight of DEHP or corn oil (CON) throughout pregnancy and lactation. The growth of male offspring was investigated until 14 weeks old, the indices of blood were detected, and mechanism was studied using metabonomics and transcriptomics. Compared with the CON group, body weight, body length, food intake, body fat weight, Lee's index, organ coefficient, blood lipids, and oral glucose tolerance test (OGTT) of male offspring were not significantly changed in maternal DEHP group. However, serum biochemical indexes such as alanine transaminase (ALT), total protein (TP), albumin (ALB), blood urea nitrogen (BUN), and creatinine (CREA) were markedly reduced in maternal DEHP group (p < 0.05). In addition, insulin level was elevated and catalase (CAT) level was decreased notably in maternal DEHP group compared with the CON group (p < 0.05). Furthermore, thyroxine (T₄) level was lower and thyroid stimulating hormone (TSH) level was higher in maternal DEHP group (p < 0.05). Metabonomics revealed seven principal metabolites were identified, including increased L-allothreonine, creatine, uric acid, retinyl ester, L-palmitoylcarnitine, and decreased glycocholic acid and LysoPC (18:3). Transcriptomics displayed 35 differential genes were involved in the mechanism of maternal DEHP exposure. Therefore, this research confirms the effect of a certain dose of maternal DEHP exposure on male offspring and understands exactly the mechanism of these changes with metabonomics and transcriptomics.

Association between persistent endocrine-disrupting chemicals (PBDEs, OH-PBDEs, PCBs, and PFASs) and biomarkers of inflammation and cellular aging during pregnancy and postpartum

BACKGROUND

Endocrine-disrupting chemicals (EDCs) can target immune and metabolic pathways. However, few epidemiologic studies have examined the influence of EDCs on measures of inflammation and cellular aging during pregnancy and postpartum.

OBJECTIVE

We investigated associations between prenatal exposures to polybrominated diphenyl ethers (PBDEs), hydroxylated PBDE metabolites (OH-PBDEs), polychlorinated biphenyls (PCBs), and per- and polyfluorochemicals (PFASs) with repeated biomarker measurements of inflammation and cellular aging in women during pregnancy and the postpartum period.

METHODOLOGY

Overweight or obese pregnant women were recruited from the San Francisco Bay area (n = 103) during their first or second trimester of pregnancy. Blood samples were collected from participants at baseline (median 16 weeks gestation) and at three and nine months postpartum. Serum concentrations of PBDEs, OH-PBDEs, PCBs, and PFASs were measured at baseline. Inflammation biomarkers (interleukin 6 [IL-6], interleukin 10 [IL-10], and tumor necrosis factor [TNF-α]) and leukocyte telomere length (LTL), a biomarker of cellular aging, were measured at all three time points. Associations between serum chemical concentrations and repeated measures of IL-6, IL-10, TNF-α, and LTL were examined using linear mixed models. We also examined the potential for effect modification by time (visit) and obesity.

RESULTS

In adjusted models, we observed positive relationships between PBDEs and pro-inflammatory cytokines (IL-6 and TNF-α). A doubling in ∑PBDEs was associated with a 15.26% (95% CI 1.24, 31.22) and 3.74% (95% CI -0.19, 7.82) increase in IL-6 and TNF-α, respectively. Positive associations were also observed for PFASs and IL-6. A two-fold increase in ∑PFASs was associated with a 20.87% (95% CI 3.46, 41.22) increase in IL-6. 5-OHBDE-47 was inversely associated with anti-inflammatory cytokine IL-10. Some EDC-outcome associations, including those of PBDEs with TNF-α, were stronger during pregnancy (compared to three or nine months postpartum) and among obese (compared to overweight) women (p-interaction <0.05).

CONCLUSIONS

These findings suggest that exposure to specific EDCs is associated with increased inflammation among women during pregnancy and the postpartum period. Future studies should replicate these findings in additional study populations and examine the implications of these associations for maternal and child health.

A systematic review of metabolomics biomarkers for Bisphenol A exposure

INTRODUCTION

Bisphenol A (BPA), 2,2-bis(4-hydroxyphenyl) propane, a common industrial chemical which has extremely huge production worldwide, is ubiquitous in the environment. Human have high risk of exposing to BPA and the health problems caused by BPA exposure have aroused public concern. However, the biomarkers for BPA exposure are lacking. As a rapidly developing subject, metabolomics has accumulated a large amount of valuable data in various fields. The secondary application of published metabolomics data could be a very promising field for generating novel biomarkers whilst further understanding of toxicity mechanisms.

OBJECTIVES

To summarize the published literature on the use of metabolomics as a tool to study BPA exposure and provide a systematic perspectives of current research on biomarkers screening of BPA exposure.

METHODS

We conducted a systematic search of MEDLINE (PubMed) up to the end of June 25, 2017 with the key term combinations of 'metabolomics', 'metabonomics', 'mass spectrometry', 'nuclear magnetic spectroscopy', 'metabolic profiling' and 'amino acid profile' combined with 'BPA exposure'. Additional articles were identified through searching the reference lists from included studies.

RESULTS

This systematic review included 15 articles. Intermediates of glycolysis, Krebs cycle, β oxidation of long chain fatty acids, pentose phosphate pathway, nucleoside metabolism, branched chain amino acid metabolism, aromatic amino acids metabolism, sulfur-containing amino acids metabolism were significantly changed after BPA exposure, suggesting BPA had a highly complex toxic effects on organism which was consistent with existing studies. The biomarkers most consistently associated with BPA exposure were lactate and choline.

CONCLUSION

Existing metabolomics studies of BPA exposure present heterogeneous findings regarding metabolite profile characteristics. We need more evidence from target metabolomics and epidemiological studies to further examine the reliability of these biomarkers which link to low, environmentally relevant, exposure of BPA in human body.