In utero exposure to cigarette smoke dysregulates human fetal ovarian developmental signalling

Exposure to Polycyclic Aromatic Hydrocarbons and adverse reproductive outcomes in women: current status and future perspectives

OBJECTIVES

Polycyclic Aromatic Hydrocarbons (PAHs) are ubiquitous, toxic environmental chemicals that can cause adverse reproductive health effects. The objectives of this mini-review are to highlight the adverse reproductive outcomes due to PAH exposure with the main focus on polycystic ovary syndrome (PCOS) and premature ovarian failure (POF) and to provide perspectives on future research needs.

CONTENT

We reviewed studies that have reported the adverse reproductive outcomes associated with PAHs exposures in women through a comprehensive search of bibliographic databases and gray literature sources. In addition, potentially modifiable sources of exposure to PAHs and associated reproductive outcomes were also investigated.

SUMMARY

A total of 232 papers were retrieved through a comprehensive search of bibliographic databases, out of which three studies met the eligibility criteria and were included in the review. Results showed that exposure to PAHs is associated with adverse reproductive outcomes defined as PCOS, POF, and reproductive hormone imbalance. Sources of PAH exposure associated with adverse reproductive outcomes include active and passive tobacco smoking, specific cooking methods, and pesticides.

OUTLOOK

Future studies are warranted to examine the mechanisms by which PAHs result in adverse reproductive endpoints in women. Further, environmental exposures that are potentially modifiable such as exposure to tobacco smoke, may contribute to PAH exposure, and these exposures should be targeted in future policies and interventions.

Premature ovarian insufficiency: a review on the role of tobacco smoke, its clinical harm, and treatment

Premature ovarian insufficiency (POI) is a condition in which the quantity of follicles and the quality of oocytes gradually decrease. This results in an estrogen secretion disorder and abnormal follicle development, which can lead to related diseases, early onset of menopause, sexual dysfunction, and an increased risk of cardiovascular issues, osteoporosis, and depression, among others. This disease significantly impacts the physical and mental health and overall quality of life of affected women. Factors such as genetic abnormalities, oophorectomy, radiotherapy for malignancy, idiopathic conditions, and an unhealthy lifestyle, including smoking, can accelerate the depletion of the follicular pool and the onset of menopause. Extensive research has been conducted on the detrimental effects of tobacco smoke on the ovaries. This article aims to review the advancements in understanding the impact of tobacco smoke on POI, both in vivo and in vitro. Furthermore, we explore the potential adverse effects of common toxicants found in tobacco smoke, such as polycyclic aromatic hydrocarbons (PAHs), heavy metals like cadmium, alkaloids like nicotine and its major metabolite cotinine, benzo[a]pyrene, and aromatic amines. In addition to discussing the toxicants, this article also reviews the complications associated with POI and the current state of research and application of treatment methods. These findings will contribute to the development of more precise treatments for POI, offering theoretical support for enhancing the long-term quality of life for women affected by this condition.

Fertility loss: negative effects of environmental toxicants on oogenesis

There has been a global decline in fertility rates, with ovulatory disorders emerging as the leading cause, contributing to a global lifetime infertility prevalence of 17.5%. Formation of the primordial follicle pool during early and further development of oocytes after puberty is crucial in determining female fertility and reproductive quality. However, the increasing exposure to environmental toxins (through occupational exposure and ubiquitous chemicals) in daily life is a growing concern; these toxins have been identified as significant risk factors for oogenesis in women. In light of this concern, this review aims to enhance our understanding of female reproductive system diseases and their implications. Specifically, we summarized and categorized the environmental toxins that can affect oogenesis. Here, we provide an overview of oogenesis, highlighting specific stages that may be susceptible to the influence of environmental toxins. Furthermore, we discuss the genetic and molecular mechanisms by which various environmental toxins, including metals, cigarette smoke, and agricultural and industrial toxins, affect female oogenesis. Raising awareness about the potential risks associated with toxin exposure is crucial. However, further research is needed to fully comprehend the mechanisms underlying these effects, including the identification of biomarkers to assess exposure levels and predict reproductive outcomes. By providing a comprehensive overview, this review aims to contribute to a better understanding of the impact of environmental toxins on female oogenesis and guide future research in this field.

BPA disrupts meiosis I in oogonia by acting on pathways including cell cycle regulation, meiosis initiation and spindle assembly

The negative in utero effects of bisphenol A (BPA) on female reproduction are of concern since the ovarian reserve of primordial follicles is constituted during the fetal period. This time-window is difficult to access, particularly in humans. Animal models and explant culture systems are, therefore, vital tools for investigating EDC impacts on primordial germ cells (PGCs). Here, we investigated the effects of BPA on prophase I meiosis in the fetal sheep ovary. We established an in vitro model of early gametogenesis through retinoic acid (RA)-induced differentiation of sheep PGCs that progressed through meiosis. Using this system, we demonstrated that BPA (3×10^-7 M & 3×10^-5M) exposure for 20 days disrupted meiotic initiation and completion in sheep oogonia and induced transcriptomic modifications of exposed explants. After exposure to the lowest concentrations of BPA (3×10^-7M), only 2 probes were significantly up-regulated corresponding to NR2F1 and TMEM167A transcripts. In contrast, after exposure to 3×10^-5M BPA, 446 probes were deregulated, 225 were down- and 221 were up-regulated following microarray analysis. Gene Ontology (GO) annotations of differentially expressed genes revealed that pathways mainly affected were involved in cell-cycle phase transition, meiosis and spindle assembly. Differences in key gene expression within each pathway were validated by qRT-PCR. This study provides a novel model for direct examination of the molecular pathways of environmental toxicants on early female gametogenesis and novel insights into the mechanisms by which BPA affects meiosis I. BPA exposure could thereby disrupt ovarian reserve formation by inhibiting meiotic progression of oocytes I and consequently by increasing atresia of primordial follicles containing defective oocytes.

The effects of polycyclic aromatic compounds (PACs) on mammalian ovarian function

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Toxicity of polycyclic aromatic compounds (PACs) is limited to a subset of PACs.

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Exposure to these compounds impact major processes necessary for ovarian function.

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PAC exposure causes follicle loss and aberrant steroid production and angiogenesis.

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PAC exposure may increase the risk for impaired fertility and ovarian pathologies.

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The study of PACs as ovarian toxicants should include additional compounds.

Polycyclic aromatic compounds (PACs) are a broad class of contaminants ubiquitously present in the environment due to natural and anthropogenic activities. With increasing industrialization and reliance on petroleum worldwide, PACs are increasingly being detected in different environmental compartments. Previous studies have shown that PACs possess endocrine disruptive properties as these compounds often interfere with hormone signaling and function. In females, the ovary is largely responsible for regulating reproductive and endocrine function and thus, serves as a primary target for PAC-mediated toxicity. Perturbations in the signaling pathways that mediate ovarian folliculogenesis, steroidogenesis and angiogenesis can lead to adverse reproductive outcomes including polycystic ovary syndrome, premature ovarian insufficiency, and infertility. To date, the impact of PACs on ovarian function has focused predominantly on polycyclic aromatic hydrocarbons like benzo(a)pyrene, 3-methylcholanthrene and 7,12-dimethylbenz[a]anthracene. However, investigation into the impact of substituted PACs including halogenated, heterocyclic, and alkylated PACs on mammalian reproduction has been largely overlooked despite the fact that these compounds are found in higher abundance in free-ranging wildlife. This review aims to discuss current literature on the effects of PACs on the ovary in mammals, with a particular focus on folliculogenesis, steroidogenesis and angiogenesis, which are key processes necessary for proper ovarian functions.

Benzo[ghi]perylene induces cellular dormancy signaling and endoplasmic reticulum stress in NL-20 human bronchial epithelial cells

Benzo[ghi]perylene (BghiP) is produced by the incomplete combustion of gasoline and it is a marker of high vehicular flow in big cities. Nowadays, it is known that BghiP functions as ligand for the aryl hydrocarbon receptor (AhR), which can cause several molecular responses. For this reason, the aim of the present study was to assess the in vitro effects of the exposure to BghiP, specifically, the induction of cellular dormancy and endoplasmic reticulum stress (ER stress) in NL-20 human cells. Our results proved that a 24 h exposure of BghiP, increased the expression of NR2F1 (p < 0.05). NR2F1 is the main activator of cell dormancy, therefore, we analyzed the expression of its target genes SOX9 and p27 showing an increase of the transcripts (p < 0.05), suggesting a pathway that could produce a cell cycle arrest. Interestingly, this effect was only observed with BghiP exposure, and not with a classic AhR ligand: benzo[a]pyrene. Moreover, in the presence of the AhR antagonist, CH223191, or when the expression of AhR was knock-down using dsiRNAs, the cellular dormancy signaling pathway was blocked. Morphological and ultrastructure analysis demonstrated that BghiP also induces ER stress, characterized by the dilated ER cisternae and the overexpression of PERK and CHOP genes (p < 0.05). Moreover, the halt of cell proliferation and the ER stress are both associated to the increase of pro-inflammatory cytokines (IL-6 and IL-8) and the cell survival in response to microenvironmental cues. These responses induced by BghiP on bronchial cells open new horizons on the research of other biological effects induced by environmental pollutants.

The Impact of Early-Life Exposures on Women's Reproductive Health in Adulthood

Purpose of Review

To review the effects of early-life, preconception, and prior-generation exposures on reproductive health in women.

Recent Findings

Women’s early-life factors can affect reproductive health by contributing to health status or exposure level on entering pregnancy. Alternately, they can have permanent effects, regardless of later-life experience. Nutrition, social class, parental smoking, other adverse childhood experiences, environmental pollutants, infectious agents, and racism and discrimination all affect reproductive health, even if experienced in childhood or in utero. Possible transgenerational effects are now being investigated through three- or more-generation studies. These effects occur with mechanisms that may include direct exposure, behavioral, endocrine, inflammatory, and epigenetic pathways.

Summary

Pregnancy is increasingly understood in a life course perspective, but rigorously testing hypotheses on early-life effects is still difficult. In order to improve the health outcomes of all women, we need to expand our toolkit of methods and theory.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40471-021-00279-0.

Impaired fecundity as a marker of health and survival: a Danish twin cohort study

STUDY QUESTION

Is fecundity, measured as self-reported time to first pregnancy (TTP), a marker for subsequent health and survival?

SUMMARY ANSWER

Long TTP was a marker for increased mortality among women and higher hospitalization rates for both women and men.

WHAT IS KNOWN ALREADY

Poor semen quality has been linked to increased mortality and morbidity from a wide range of diseases. Associations among fecundity, health and survival among women are still uncertain and studies on actual measures of fecundity and health outcomes are rare.

STUDY DESIGN, SIZE, DURATION

We performed a prospective cohort study of 7825 women and 6279 men, aged 18 and above with measures on first TTP, who participated in one of the Danish nation-wide twin surveys in 1994 (twins born 1953-1976) and 1998 (twins born 1931-1952). They were followed-up for mortality and hospital admissions from the interview until 2018.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Twins were identified in the Danish Twin Registry and linked to Danish registers. TTP was restricted to the first pregnancy as a categorical outcome with cut-off points at 2, 10 and 18 months. We analysed the association between TTP and survival using a Cox proportional hazards model estimating hazards ratios (HRs) with 95% confidence intervals (CIs). Fine-Gray survival models were used to estimate sub-hazard ratios for specific causes of death allowing for competing risks. Using negative binomial regression, we estimated incidence rate ratios (IRRs) with 95% CIs for all-cause and cause-specific hospitalizations. All analyses were stratified by sex and adjusted for age at interview, birth cohorts, age at first attempt to become pregnant, smoking, years in school and BMI.

MAIN RESULTS AND THE ROLE OF CHANCE

In the total study population, 49.9% of women and 52.7% of men reported a TTP of less than 2 months, 30.8% of women and 29.6% of men reported a TTP of 2-9 months, 6.6% of women and 5.7% of men reported a TTP of 10-17 months, and 13.3% of women and 12.0% of men reported a TTP of 18 months or more. Among 1305 deaths, we found a higher mortality for women (HR = 1.46; 95% CI 1.15, 1.87) with a TTP of ≥18 months relative to those with a TTP of <2 months, while the highest mortality was indicated for men with a TTP of 10-17 months (HR = 1.31; 95% CI 0.98, 1.74). Among 53 799 hospitalizations, we found an increased hospitalization rate among women (HR = 1.21; 95% CI 1.0-1.41) and men (HR = 1.16; 95% CI 1.00-1.35) with a TTP of ≥18 months, and for men with a TTP of 2-9 months (HR = 1.14; 95% CI 1.01-1.30). A dose-response relationship was found for women regarding both mortality (P = 0.022) and hospitalizations (P = 0.018). Impaired fecundity was associated with a wide range of diseases and some causes of death, indicating a multi-factorial causal influence on fecundity, especially among women.

LIMITATIONS, REASONS FOR CAUTION

A major limitation was that fecundity depends on both partners, which was not considered in this study. Moreover, we could not obtain information on a number of potential confounders.

WIDER IMPLICATIONS OF THE FINDINGS

Fecundity seems positively correlated with overall health and may be a universal marker of future health and survival. These results add knowledge to the limited findings showing that reduced fecundity in women and poor semen quality in men may reflect worse health and a shorter life, particularly among women.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by NIH grant HD096468 (M.L.E., T.K.J. and R.L.J.). The authors declare that they have no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Six Decades of Research on Human Fetal Gonadal Steroids

Human fetal gonads acquire endocrine steroidogenic capabilities early during their differentiation. Genetic studies show that this endocrine function plays a central role in the sexually dimorphic development of the external genitalia during fetal development. When this endocrine function is dysregulated, congenital malformations and pathologies are the result. In this review, we explain how the current knowledge of steroidogenesis in human fetal gonads has benefited from both the technological advances in steroid measurements and the assembly of detailed knowledge of steroidogenesis machinery and its expression in human fetal gonads. We summarise how the conversion of radiolabelled steroid precursors, antibody-based assays, mass spectrometry, ultrastructural studies, and the in situ labelling of proteins and mRNA have all provided complementary information. In this review, our discussion goes beyond the debate on recommendations concerning the best choice between the different available technologies, and their degrees of reproducibility and sensitivity. The available technologies and techniques can be used for different purposes and, as long as all quality controls are rigorously employed, the question is how to maximise the generation of robust, reproducible data on steroid hormones and their crucial roles in human fetal development and subsequent functions.

Effects of PM2.5 exposure on reproductive system and its mechanisms

With the development of human society, haze has become an important form of air pollution. Haze is a mixture of fog and haze, and the main component of haze is fine particulate matter (PM_2.5), which is the most important indicator of composite air pollution. Epidemiological studies proved that PM_2.5 can break through the respiratory mucosal barrier and enter the human body, causing pathological effects on multiple systems of the body. In the past, people put more attention to PM_2.5 in the respiratory system, cardiovascular system, nervous system, etc, and relatively paid less attention to the reproductive system. Recent studies have shown that PM_2.5 will accumulate in the reproductive organs through blood-testis barrier, placental barrier, epithelial barrier and other barriers protecting reproductive tissues. In addition, PM_2.5 can disrupt hormone levels, ultimately affecting fertility. Prior studies have shown that oxidative stress, inflammation, apoptosis, and the breakdown of barrier structures are now considered to contribute to reproductive toxicity and may cause damage at the molecular and genetic levels. However, the exact mechanism remains to be elucidated. Our review aims to provide an understanding of the pathological effects of PM_2.5 on reproductive system and the existing injury mechanism.

Prenatal smoke exposure is associated with increased anogenital distance in female infants: a prospective case-control study

OBJECTIVES

To investigate the effects of maternal smoking during pregnancy on newborn infants' anogenital distance (AGD).

METHODS

Fifty-six female and sixty-four male newborn infants from mothers who smoked during pregnancy were included in this study. A control group for each sex was selected from infants whose mothers had no active or passive (in either the household or the workplace) smoke exposure before or during pregnancy. Questionnaire data on maternal demographic characteristics and information about cigarette use were collected. We assessed genital anthropometry which included AGD for both male and female neonates, and stretched penile length (SPL), penile girth for males within the first 48 h after birth. AGD measurements were also normalized according to birth weight (AGD/weight in grams), length (AGD/height in millimeters), and ponderal index [AGD/(weight in grams/height in cubic centimeters)]. Anogenital index (AGI) was calculated by dividing the AGD by cube root of birth weight.

RESULTS

In female infants, prenatal smoke exposure was associated with significantly increased weight-adjusted AGD (p=0.03). There was also a significant correlation between mothers' daily smoking rates and weight-adjusted AGD (r=0.27/p=0.03). In male infants, fetal smoke exposure was not associated with any AGD measurements, SPL and penile girth.

CONCLUSIONS

A significant increase in weight-adjusted AGD in female infants exposed to maternal smoking may be an indicator of antenatal androgen exposure and may pose a risk for short and long-term endocrine, metabolic and behavioral problems.

Recalled maternal lifestyle behaviors associated with anti-müllerian hormone of adult female offspring

Anti-müllerian hormone (AMH) is an established marker of ovarian reserve that decreases with age. Though the pool of ovarian follicles is established during fetal development, impacts of in utero exposures on AMH are uncertain. Thus, we sought to evaluate associations of in utero exposures with AMH of adult daughters with a prospective cohort study of adult daughters at university medical centers. Women noted their mother's reported use of diethylstilbestrol (DES), vitamins, tobacco, alcohol, and caffeine during pregnancy, and their mother's occupation during pregnancy. All participants were reproductive age women (18-40 years) enrolled in the Effects of Aspirin in Gestation and Reproduction (EAGeR) trial. Serum AMH concentrations were measured at baseline prior to conception and categorized using clinical guidelines. Multinomial regression models estimated associations between each exposure and high (>3.5 ng/mL) and low (<1.0 ng/mL) versus normal AMH (1.0-3.5 ng/mL), adjusting for participant's age, mother's age, mother's history of fertility treatment, and mother's use of vitamins. In 1202 women with available data, maternal caffeine use was associated with an increased risk of low AMH, compared to normal (relative risk [RR] 1.90, 95 % confidence interval [CI] 1.09, 3.30). Vitamins were associated with an increased risk of high AMH compared to normal (RR 1.93, 95 % CI 1.24, 3.00). Other exposures were not associated with AMH concentrations in offspring. Maternal caffeine and vitamin use during pregnancy may be associated with ovarian reserve in adult offspring, highlighting the potential importance of pregnancy lifestyle on the reproductive health of daughters.

In utero Exposure to Nicotine Containing Electronic Cigarettes Increases the Risk of Allergic Asthma in Female Offspring

E-cigarettes (eCig) are being considered as an alternative to quit cigarette smoking while their long-term effect on lung pathophysiology are unknown. Maternal eCig-vaping may be promoted and considered as a safer cigarette smoking-replacement during pregnancy thus needing further assessment. Using murine models of in utero vaping and allergic asthma with complementary in vitro experiments we tested whether maternal eCig vaping enhances features of allergic asthma in offspring. Female BALB/c mice were exposed to either eCig vapor (± nicotine) or room air. Female offspring from these mothers were subjected to an ovalbumin (OVA)-induced allergic asthma model. Lung function and airway inflammation was assessed. Tissues were histologically assessed with H&E, Periodic Acid-Schiff and Masson's trichrome. Mitochondrial homeostasis protein expression was measured using immunohistochemistry while human airway smooth muscle (ASM) and Beas-2B cells were used to further measure cellular function and mitochondrial respiration. Allergen-challenge in mice lead to significant increase in airway inflammation, development of airway hyperresponsiveness (AHR) and increase in mucus and airway wall thickening (hallmark features of allergic asthma). Allergic asthma features were significantly enhanced in offspring from eCig (+Nicotine)-exposed mothers and were mainly reliant upon Th2-dependent inflammation with complementary changes in mitochondrial homeostasis. Further, in vitro data demonstrated that eCig (±Nicotine)-exposure impaired airway cell homeostasis and perturbed mitochondrial function. Collectively, maternal eCig vaping enhanced and worsened features of allergic asthma and this could partly be attributed to aberrant mitochondrial function.

Melatonin ameliorates murine fetal oocyte meiotic dysfunction in F1 and F2 offspring caused by nicotine exposure during pregnancy

Although there is abundant evidence to demonstrate that maternal smoking during pregnancy will harm the health of future generations, the impact of nicotine use by pregnant woman upon the oogenesis and folliculogenesis of female offspring has not been as widely scrutinized. Here we focus on the effects of nicotine on the meiotic progression of fetal oocytes. The data indicated that in pregnant mice treated with nicotine, intracellular ROS increased in follicles within the fetal ovary. Excessive intracellular hydrogen peroxide (H₂O₂) and superoxide anion (O₂^-) decreased mitochondrial membrane potential, inducing mitochondrial dysfunction, triggering an autophagic cascade and inhibiting anti-autophagic proteins. Fetal oocytes in F1 offspring of pregnant mice treated with nicotine exhibited a delay in meiotic prophase I, especially from the stage of pachytene to diplotene. In pubertal F1 offspring we observed a reduced number of follicles; the same reduction was also observed in F2 offspring. Of note, we found that melatonin ameliorated nicotine-induced oocyte damage and increased the expression of MnSOD, which decreased the production of nicotine-induced intracellular ROS. In addition, melatonin also maintained normal H3K4 and H3K9 di- and tri-methylation in F1 and F2 ovaries. Taken together, the current evidence suggests that, in the mouse, melatonin could prevent nicotine-impaired fetal oogenesis and folliculogenesis in offspring.

Putative adverse outcome pathways for female reproductive disorders to improve testing and regulation of chemicals

Modern living challenges female reproductive health. We are witnessing a rise in reproductive disorders and drop in birth rates across the world. The reasons for these manifestations are multifaceted and most likely include continuous exposure to an ever-increasing number of chemicals. The cause–effect relationships between chemical exposure and female reproductive disorders, however, have proven problematic to determine. This has made it difficult to assess the risks chemical exposures pose to a woman’s reproductive development and function. To address this challenge, this review uses the adverse outcome pathway (AOP) concept to summarize current knowledge about how chemical exposure can affect female reproductive health. We have a special focus on effects on the ovaries, since they are essential for lifelong reproductive health in women, being the source of both oocytes and several reproductive hormones, including sex steroids. The AOP framework is widely accepted as a new tool for toxicological safety assessment that enables better use of mechanistic knowledge for regulatory purposes. AOPs equip assessors and regulators with a pragmatic network of linear cause–effect relationships, enabling the use of a wider range of test method data in chemical risk assessment and regulation. Based on current knowledge, we propose ten putative AOPs relevant for female reproductive disorders that can be further elaborated and potentially be included in the AOPwiki. This effort is an important step towards better safeguarding the reproductive health of all girls and women.

[In Utero Exposure to Maternal Smoking: Impact on the Child from Birth to Adulthood - CNGOF-SFT Expert Report and Guidelines for Smoking Management during Pregnancy]

INTRODUCTION

Smoking during pregnancy leads to fetal passive smoking. It is associated with several obstetrical complications and is a major modifiable factor of maternal and fetal morbidity. Long-term consequences also exist but are less well known to health professionals and in the general population.

METHODS

Consultation of the Medline® database.

RESULTS

Maternal smoking during pregnancy is associated in the offspring with sudden infant death syndrome (NP2), impaired lung function (NP2), lower respiratory infections and asthma (NP2), overweight and obesity (NP2), cancers (NP3), risk of tobacco use, nicotine dependence and early smoking initiation (NP2). Unadjusted analyses show associations between in utero tobacco exposure and cognitive deficits (NP3), impaired school performance (NP3) and behavioral disorders in children (NP2), which are in a large part explained by environmental factors. There is a cross-generational effect of smoking during pregnancy. For example, an increased risk of asthma is observed in the grandchildren of smoking women (NP4). The respective roles of ante- and post-natal smoking remain difficult to assess.

CONCLUSION

These results highlight the importance of prevention measures against tobacco use in the general population, as well as screening measures and support for smoking cessation before or at the beginning of the pregnancy.

Trichostatin A alleviated ovarian tissue damage caused by cigarette smoke exposure

Cigarette smoke (CS) has a negative impact on women's health and fertility. Studies have shown that histone deacetylases 1 and 2 (HDAC1/2) were involved in oocyte development. However, the roles of HDAC1/2 in ovarian toxicity caused by CS exposure and the therapeutic potential of trichostatin A (TSA, a HDAC inhibitor) for ovarian tissue damage have not been investigated. In this study, Female C57BL/6 mice were exposed to CS from six cigarettes mixed with indoor air for 120 min (one cigarette for 20 min) using a whole-body mainstream smoke exposure system twice daily for 30 days. TSA (0.6 mg/kg body weight) was injected intraperitoneally into mice in the Control + TSA group and CS + TSA group every two days for 30 days. We found that exposure to CS resulted in ovarian tissue damage and HDAC1/2 over-expression. TSA alleviated the structural changes of ovarian tissue induced by smoking and prevented the activation of HDAC1/2. Exposure to CS caused autophagy inhibition and pyroptosis activation. TSA treatment restored the expression of autophagy-associated proteins and decreased the levels of pyroptosis-related proteins induced by CS exposure. The TSA effect may be mediated by inhibition of HDAC1/2 involved in autophagy and pyroptosis process.

Smoke, alcohol and drug addiction and female fertility

BACKGROUND

Considerable interest has been gathered on the relevant impact of preventable factors, including incorrect lifestyle and unhealthy habits, on female fertility. Smoking, alcohol and addictive drugs consumption represent a major concern, given the broad range of diseases which might be favored or exacerbated by these dependable attitudes. Despite the well-characterized effects of prenatal exposure on pregnancy outcomes and fetus health, a substantial proportion of women of reproductive age is still concerned with these habits. At present, the impact of smoke, alcohol and addictive drugs on women fertility, and, particularly, the specific targets and underlying mechanisms, are still poorly understood or debated, mainly due to the scarcity of well-designed studies, and to numerous biases.

OBJECTIVE

The current review will provide a comprehensive overview of clinical and experimental studies in humans and animals addressing the impact of smoke, alcohol and addictive drugs on female fertility, by also embracing effects on ovary, oviduct, and uterus, with particular reference to primary endpoints such as ovarian reserve, steroidogenesis, ovulation and menstrual cycle, oviduct function and uterus receptivity and implantation. A brief focus on polycystic ovary syndrome and endometriosis will be also included.

METHODS

A Pubmed literature search was performed with selected keywords; articles were individually retrieved by each author. No limitation was set for publication date. Articles in languages other than English were excluded. Additional articles were retrieved from references list of selected manuscripts.

RESULTS AND CONCLUSIONS

Currently, the most consistent evidences of a detrimental effect of smoke, alcohol and addictive drugs on specific domains of the female reproductive function are provided by experimental studies in animals. Overall, clinical studies suggest that smoking is associated to decreased fertility, although causal inference should be further demonstrated. Studies addressing the effect of alcohol consumption on female fertility provide conflicting results, although the majority reported lack of a correlation. Extremely scarce studies investigated the effects of addictive drugs on female fertility, and the specific actions of selected drugs have been difficult to address, due to multidrug consumption.

Protective effects of melatonin against nicotine-induced disorder of mouse early folliculogenesis

In this paper, we show that neonatal mice injected for five consecutive days with nicotine display impaired germ cell cyst breakdown and primordial follicle assembly resulting in decreased ovarian reserve lasting until sex maturation age. The effects of nicotine on the pups ovaries were associated with decreased expression of oocyte specific genes such as Nobox, Lhx8, Figlα and Sohlh2. Moreover, the ovaries of pups injected with nicotine showed increased level of cell oxidative stress and autophagic markers (upregulation of AMPKα-1, increased ratio LC3-II/LC3-I, downregulation of AKT and mTOR). Noteworthy, all these effects were counteracted by the administration of the hormone melatonin in 1 μM. In vitro culture of 0 dpp ovaries for 5 days in the presence of 10 μM nicotine reproduced its effect on germ cell cyst breakdown and primordial follicle assembly, furthermore it also revealing about 20% reduction of somatic cells proliferation, and these effects was prevented when melatonin was added to the medium. Taken together these results show that nicotine exposure can adversely affect the establishment of the ovarian reserve in the mouse likely by locally inducing cellular stress altering the primordial follicle assembly and that melatonin, however, is able to counteract such effects.

Chronic intermittent electronic cigarette exposure induces cardiac dysfunction and atherosclerosis in apolipoprotein-E knockout mice

Electronic cigarettes (e-cigarettes), also known as electronic nicotine delivery systems, are a popular alternative to conventional nicotine cigarettes, both among smokers and those who have never smoked. In spite of the widespread use of e-cigarettes and the proposed detrimental cardiac and atherosclerotic effects of nicotine, the effects of e-cigarettes on these systems are not known. In this study, we investigated the cardiovascular and cardiac effects of e-cigarettes with and without nicotine in apolipoprotein-E knockout (ApoE^-/-) mice. We developed an e-cigarette exposure model that delivers nicotine in a manner similar to that of human e-cigarettes users. Using commercially available e-cigarettes, bluCig PLUS, ApoE^-/- mice were exposed to saline, e-cigarette without nicotine [e-cigarette (0%)], and e-cigarette with 2.4% nicotine [e-cigarette (2.4%)] aerosol for 12 wk. Echocardiographic data show that mice treated with e-cigarette (2.4%) had decreased left ventricular fractional shortening and ejection fraction compared with e-cigarette (0%) and saline. Ventricular transcriptomic analysis revealed changes in genes associated with metabolism, circadian rhythm, and inflammation in e-cigarette (2.4%)-treated ApoE^-/- mice. Transmission electron microscopy revealed that cardiomyocytes of mice treated with e-cigarette (2.4%) exhibited ultrastructural abnormalities indicative of cardiomyopathy. Additionally, we observed increased oxidative stress and mitochondrial DNA mutations in mice treated with e-cigarette (2.4%). ApoE^-/- mice on e-cigarette (2.4%) had also increased atherosclerotic lesions compared with saline aerosol-treated mice. These results demonstrate adverse effects of e-cigarettes on cardiac function in mice.NEW & NOTEWORTHY The present study is the first to show that mice exposed to nicotine electronic cigarettes (e-cigarettes) have decreased cardiac fractional shortening and ejection fraction in comparison with controls. RNA-seq analysis reveals a proinflammatory phenotype induced by e-cigarettes with nicotine. We also found increased atherosclerosis in the aortic root of mice treated with e-cigarettes with nicotine. Our results show that e-cigarettes with nicotine lead to detrimental effects on the heart that should serve as a warning to e-cigarette users and agencies that regulate them.

Effects of environmental contaminants on fertility and reproductive health

Recent research indicates that the human infertility rate is increasing. Although various reasons have been hypothesized for the growing infertility rate, environmental contaminants are potentially important causal agents associated with this change. Chemical contaminants are widespread throughout our environment and human exposure is virtually unavoidable. The overall contribution of environmental exposure to infertility is unknown, but studies involving occupational exposure, together with results from animal experiments, suggest that environmental contaminants may adversely affect fertility. We reviewed the adverse effects of environmental exposure on fertility and related reproductive outcomes. Environmental contaminants covered in this review include heavy metals, organic solvents, pesticides and endocrine disrupting chemicals. It is hoped that this review will highlight the need for further research in this area.

Nicotine exposure impairs germ cell development in human fetal ovaries cultured in vitro

In the present paper, we found that human fetal ovaries (at ~16 weeks) express the transcripts for several subunits of the nicotinic acetylcholine receptor (nAChR). Exposure to the drug in vitro resulted in the marked increase of apoptosis in the ovaries in a time and dose-dependent manner. Evidence that adverse nicotine effects are potentially due to an increased level of reactive oxygen species (ROS) and consequent DNA damage, both in the ovarian somatic cells and germ cells, are reported. After 4 days of culture, exposure to 1 mM and 10 mM nicotine caused a 50% and 75% decrease, respectively, in the number of oogonia/oocytes present in the fetal ovaries. These results represent the first indication that nicotine may directly cause apoptosis in cells of the fetal human ovary and may lead to a reduction of the ovarian reserve oocytes and consequent precocious menopause in mothers smoking during pregnancy.

Impact of a gestational exposure to diesel exhaust on offspring gonadal development: experimental study in the rabbit

The aim of the present work was to address experimentally the possible impact of exposure to air pollution during gestation on the differentiation and function of the gonads of the offspring using a rabbit model. Rabbits were exposed daily to diluted diesel exhaust gas or filtered air from the 3rd until the 27th day of gestation, during which time germ cells migrate in genital ridges and divide, and fetal sex is determined. Offspring gonads were collected shortly before birth (28th day of gestation) or after puberty (7.5 months after birth). The structure of the gonads was analyzed by histological and immunohistological methods. Serum concentrations of testosterone and anti-Müllerian hormone were determined using ELISA. The morphology and the endocrine function of the gonads collected just at the arrest of the exposure were similar in polluted and control animals in both sexes. No differences were observed as well in gonads collected after puberty. Sperm was collected at the head of the epididymis in adults. Sperm motility and DNA fragmentation were measured. Among all parameters analyzed, only the sperm DNA fragmentation rate was increased three-fold in exposed males. Mechanisms responsible for these modifications and their physiological consequences are to be further clarified.

Prenatal exposures and birth indices, and subsequent risk of polycystic ovary syndrome: a national registry-based cohort study

OBJECTIVE

To study the associations between prenatal exposures and risk of developing polycystic ovary syndrome (PCOS).

DESIGN

National registry-based cohort study.

SETTING

Sweden.

POPULATION

Girls born in Sweden during the years 1982-1995 (n = 681 123).

METHODS

The girls were followed until the year 2010 for a diagnosis of PCOS. We estimated the associations between maternal body mass index (BMI), smoking, and size at birth with the risk of developing a PCOS diagnosis. Risks were calculated by adjusted hazard ratio (aHR) and 95% confidence intervals (95% CIs).

MAIN OUTCOME MEASURES

A diagnosis of PCOS at 15 years of age or later.

RESULTS

During the follow-up period 3738 girls were diagnosed with PCOS (0.54%). Girls with mothers who were overweight or obese had 1.5-2.0 times higher risk of PCOS (aHR 1.52, 95% CI 1.36-1.70; aHR 1.97, 95% CI 1.61-2.41, respectively), compared with girls born to mothers of normal weight. The risk of PCOS was increased if the mother smoked during pregnancy (1-9 cigarettes/day, aHR 1.31, 95% CI 1.18-1.47; ≥10 cigarettes/day, aHR 1.44, 95% CI 1.27-1.64). Being born small for gestational age (SGA) was associated with a later diagnosis of PCOS in crude estimates, but the association was not significant after adjusting for maternal factors.

CONCLUSIONS

Maternal smoking and increased BMI appear to increase the risk of PCOS in offspring. The association between SGA and the development of PCOS appears to be mediated by maternal factors.

TWEETABLE ABSTRACT

Smoking during pregnancy and high maternal BMI are associated with PCOS diagnosis in the offspring.

Glutathione deficiency sensitizes cultured embryonic mouse ovaries to benzo[a]pyrene-induced germ cell apoptosis

Mice lacking the modifier subunit of glutamate cysteine ligase (Gclm), the rate-limiting enzyme in glutathione (GSH) synthesis, have decreased tissue GSH. We previously showed that Gclm-/- embryos have increased sensitivity to the prenatal in vivo ovarian toxicity of the polycyclic aromatic hydrocarbon benzo[a]pyrene (BaP) compared with Gclm+/+ littermates. We also showed that BaP-induced germ cell death in cultured wild type embryonic ovaries is caspase-dependent. Here, we hypothesized that GSH deficiency increases sensitivity of cultured embryonic ovaries to BaP-induced germ cell death. 13.5 days post coitum (dpc) embryonic ovaries of all Gclm genotypes were fixed immediately or cultured for 24 h in media supplemented with DMSO vehicle or 500 ng/ml BaP. The percentage of activated caspase-3 positive germ cells varied significantly among groups. Within each genotype, DMSO and BaP-treated groups had increased germ cell caspase-3 activation compared to uncultured. Gclm+/- ovaries had significantly increased caspase-3 activation with BaP treatment compared to DMSO, and caspase-3 activation increased non-significantly in Gclm-/- ovaries treated with BaP compared to DMSO. There was no statistically significant effect of BaP treatment on germ cell numbers at 24 h, consistent with our prior observations in wild type ovaries, but Gclm-/- ovaries in both cultured groups had lower germ cell numbers than Gclm+/+ ovaries. There were no statistically significant BaP-treatment or genotype-related differences among groups in lipid peroxidation and germ cell proliferation. These data indicate that Gclm heterozygous or homozygous deletion sensitizes embryonic ovaries to BaP- and tissue culture-induced germ cell apoptosis.

Effects of environmental Bisphenol A exposures on germ cell development and Leydig cell function in the human fetal testis

BACKGROUND

Using an organotypic culture system termed human Fetal Testis Assay (hFeTA) we previously showed that 0.01 μM BPA decreases basal, but not LH-stimulated, testosterone secreted by the first trimester human fetal testis. The present study was conducted to determine the potential for a long-term antiandrogenic effect of BPA using a xenograft model, and also to study the effect of BPA on germ cell development using both the hFETA and xenograft models.

METHODS

Using the hFeTA system, first trimester testes were cultured for 3 days with 0.01 to 10 μM BPA. For xenografts, adult castrate male nude mice were injected with hCG and grafted with first trimester testes. Host mice received 10 μM BPA (~ 500 μg/kg/day) in their drinking water for 5 weeks. Plasma levels of total and unconjugated BPA were 0.10 μM and 0.038 μM respectively. Mice grafted with second trimester testes received 0.5 and 50 μg/kg/day BPA by oral gavage for 5 weeks.

RESULTS

With first trimester human testes, using the hFeTA model, 10 μM BPA increased germ cell apoptosis. In xenografts, germ cell density was also reduced by BPA exposure. Importantly, BPA exposure significantly decreased the percentage of germ cells expressing the pluripotency marker AP-2γ, whilst the percentage of those expressing the pre-spermatogonial marker MAGE-A4 significantly increased. BPA exposure did not affect hCG-stimulated androgen production in first and second trimester xenografts as evaluated by both plasma testosterone level and seminal vesicle weight in host mice.

CONCLUSIONS

Exposure to BPA at environmentally relevant concentrations impairs germ cell development in first trimester human fetal testis, whilst gonadotrophin-stimulated testosterone production was unaffected in both first and second trimester testis. Studies using first trimester human fetal testis demonstrate the complementarity of the FeTA and xenograft models for determining the respective short-term and long term effects of environmental exposures.

Modelling foetal exposure to maternal smoking using hepatoblasts from pluripotent stem cells

The liver is a dynamic organ which is both multifunctional and highly regenerative. A major role of the liver is to process both endo and xenobiotics. Cigarettes are an example of a legal and widely used drug which can cause major health problems for adults and constitute a particular risk to the foetus, if the mother smokes during pregnancy. Cigarette smoke contains a complex mixture of thousands of different xenobiotics, including nicotine and polycyclic aromatic hydrocarbons. These affect foetal development in a sex-specific manner, inducing sex-dependant molecular responses in different organs. To date, the effect of maternal smoking on the foetal liver has been studied in vitro using cell lines, primary tissue and animal models. While these models have proven to be useful, poor cell phenotype, tissue scarcity, batch-to-batch variation and species differences have led to difficulties in data extrapolation toward human development. Therefore, in this study we have employed hepatoblasts, derived from pluripotent stem cells, to model the effects of xenobiotics from cigarette smoke on human hepatocyte development. Highly pure hepatocyte populations (>90%) were produced in vitro and exposed to factors present in cigarette smoke. Analysis of ATP levels revealed that, independent of the sex, the majority of smoking derivatives tested individually did not deplete ATP levels below 50%. However, following exposure to a cocktail of smoking derivatives, ATP production fell below 50% in a sex-dependent manner. This was paralleled by a loss metabolic activity and secretory ability in both female and male hepatocytes. Interestingly, cell depletion was less pronounced in female hepatocytes, whereas caspase activation was ~twofold greater, indicating sex differences in cell death upon exposure to the smoking derivatives tested.

Effects of maternal smoking on offspring reproductive outcomes: an intergenerational study in the North East of Scotland

STUDY QUESTION

How does exposure to cigarette smoke in utero influence women's reproductive outcomes?

SUMMARY ANSWER

Women exposed to cigarette smoke in utero were more likely to have a pregnancy and more likely to experience miscarriage.

WHAT IS ALREADY KNOWN

Existing epidemiological studies have been inconsistent, but generally suggest a small decrease in fertility of women exposed to cigarette smoke in utero.

STUDY DESIGN, SIZE, DURATION

This cohort study included all women born prior to 31st December 1972 as recorded in the Aberdeen Maternity and Neonatal Databank. Exposure to maternal cigarette smoking in utero was retrieved from their birth records within the database. The primary outcome was any pregnancy occurring in the offspring over the course of their reproductive life. The 12 321 eligible women were followed up for 40 years for any pregnancies and the outcome of those pregnancies recorded in the same database.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Within the cohort, 3836 women were exposed to cigarette smoke and 8485 women were not exposed to cigarette smoke in utero. Generalized estimating equations were used to generate odds ratios (OR) and 95% CIs for all outcomes with adjustment made for all differences between groups at baseline.

MAIN RESULTS AND THE ROLE OF CHANCE

The study did not find a link between exposure to cigarette smoke in utero and a decrease in fertility. Women exposed to cigarette smoke in utero were more likely to have a pregnancy than those whose mother did not smoke; adjusted OR = 1.25 (95% CIs: 1.13–1.38). Women exposed to cigarette smoke in utero were also likely to have a pregnancy earlier (adjusted OR for age at first delivery ≤19 years 1.31 [95% CIs: 1.12–1.54)] than those not exposed. Women exposed to cigarette smoke in utero were significantly more likely to have a miscarriage than those not exposed; adjusted OR = 1.16 (95% CIs: 1.01–1.32).

LIMITATIONS, REASONS FOR CAUTION

Although the cohort in this study was large, there were women for whom exposure data was unavailable. Data on the adult circumstances of women who did not record a pregnancy was unavailable, precluding adjustment for their own smoking status or social class. In addition, women who migrated from the area or chose childlessness voluntarily were not included in the study.

WIDER IMPLICATIONS OF THE FINDINGS

Despite the wide-ranging harmful effects of cigarette smoke on foetal reproductive development, the effect at a population level remains uncertain. An increased risk of miscarriage in women exposed to cigarette smoke is a potentially important novel finding, which should be investigated further. This study illustrates the lack of consensus on the reproductive effects of in utero cigarette exposure, compelling continuing study in this important area.

STUDY FUNDING/COMPETING INTEREST(S)

No funding received. No competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Cigarette smoke impaired maturation of ovarian follicles and normal growth of uterus inner wall of female wild-type and hypertensive rats

Cigarette smoke (CS) is well known to be very harmful to human body functions such as fertility, reproduction, and development. CS is considered to more affect patients with hypertension (HT). To estimate the effect of CS associated with female rat's fertility, we examined the histopathological characteristics of the uterus and ovary which were obtained from the female rats exposed to smoke of the standard cigarette (3R4F) for 4 weeks (10h a week) according to the OECD guidelines. The female wild-type Wistar Kyoto (WK) rats (WTR) and spontaneously hypertensive WK rats (SHR) were used to compare the effect of CS on healthy and hypertensive rats. After CS exposure, we manufactured tissue slides from uterine and ovarian samples and evaluated the maturation of follicles of ovary and cell proliferation in the uterus by H&E staining and immunohistochemistry (IHC). In IHC analysis on ovarian tissues, the expression of proliferating cell nuclear antigen (PCNA) and the number of follicles were decreased by CS exposure. On the contrary, PCNA expression and cell proliferation in the uterine inner layers were increased by CS exposure. The protein expression of C/EBP homologous protein (CHOP), an endoplasmic reticulum (ER)-stress marker, and BAX, a pro-apoptotic protein, was decreased by CS exposure. This phenomenon was more exacerbated in SHR rats than in WTR rats. Taken together, acute exposure to CS induced the decreased maturation of ovarian follicles and abnormal over-growth of uterine inner wall, leading to a harmful effect on female rat's normal function. In addition, this harmful effect of CS may be displayed more seriously in rats with HT.

Ovotoxicity of cigarette smoke: A systematic review of the literature

This study reviews the scientific literature on the noxious effects of cigarette smoke on the ovarian follicle, and the cumulative data on the impact of smoking on in vitro fertilization (IVF) cycle outcome. There is a close association between tobacco smoke and accelerated follicle loss, abnormal follicle growth and impairment of oocyte morphology and maturation. There is an increasing amount of evidence indicating that smoke can directly derange folliculogenesis. Increased cellular apoptosis or autophagy, DNA damage and abnormal crosstalk between oocyte and granulosa cells have been implicated in the demise of ovarian follicles. It becomes increasingly clear that maternal smoking can exert multigenerational effects on the ovarian function of the progeny. Growing evidence suggests that cigarette smoke is associated with decreased results after IVF. Further research is needed to better define the molecular mechanisms behind smoking-induced ovarian disruption.

Environmental influences on ovarian dysgenesis - developmental windows sensitive to chemical exposures

A woman's reproductive health and ability to have children directly affect numerous aspects of her life, from personal well-being and socioeconomic standing, to morbidity and lifespan. In turn, reproductive health depends on the development of correctly functioning ovaries, a process that starts early during fetal life. Early disruption to ovarian programming can have long-lasting consequences, potentially manifesting as disease much later in adulthood. A growing body of evidence suggests that exposure to chemicals early in life, including endocrine-disrupting chemicals, can cause a range of disorders later in life, such as those described in the ovarian dysgenesis syndrome hypothesis. In this Review, we discuss four specific time windows during which the ovary is particularly sensitive to disruption by exogenous insults: gonadal sex determination, meiotic division, follicle assembly and the first wave of follicle recruitment. To date, most evidence points towards the germ cell lineage being the most vulnerable to chemical exposure, particularly meiotic division and follicle assembly. Environmental chemicals and pharmaceuticals, such as bisphenols or mild analgesics (including paracetamol), can also affect the somatic cell lineages. This Review summarizes our current knowledge pertaining to environmental chemicals and pharmaceuticals, and their potential contributions to the development of ovarian dysgenesis syndrome. We also highlight knowledge gaps that need addressing to safeguard female reproductive health.

Environmental pollutants, a possible etiology for premature ovarian insufficiency: a narrative review of animal and human data

BACKGROUND

Because only 25% of cases of premature ovarian insufficiency (POI) have a known etiology, the aim of this review was to summarize the associations and mechanisms of the impact of the environment on this pathology. Eligible studies were selected from an electronic literature search from the PUBMED database from January 2000 to February 2016 and associated references in published studies. Search terms included ovary, follicle, oocyte, endocrine disruptor, environmental exposure, occupational exposure, environmental contaminant, pesticide, polyaromatic hydrocarbon, polychlorinated biphenyl PCB, phenol, bisphenol, flame retardant, phthalate, dioxin, phytoestrogen, tobacco, smoke, cigarette, cosmetic, xenobiotic. The literature search was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We have included the human and animal studies corresponding to the terms and published in English. We have excluded articles that included results that did not concern ovarian pathology and those focused on ovarian cancer, polycystic ovary syndrome, endometriosis or precocious puberty. We have also excluded genetic, auto-immune or iatrogenic causes from our analysis. Finally, we have excluded animal data that does not concern mammals and studies based on results from in vitro culture. Data have been grouped according to the studied pollutants in order to synthetize their impact on follicular development and follicular atresia and the molecular pathways involved. Ninety-seven studies appeared to be eligible and were included in the present study, even though few directly address POI. Phthalates, bisphenol A, pesticides and tobacco were the most reported substances having a negative impact on ovarian function with an increased follicular depletion leading to an earlier age of menopause onset. These effects were found when exposure occured at different times throughout the lifetime from the prenatal to the adult period, possibly due to different mechanisms. The main mechanism seemed to be an increase in atresia of pre-antral follicles.

CONCLUSION

Environmental pollutants are probably a cause of POI. Health officials and the general public must be aware of this environmental effect in order to implement individual and global preventive actions.

Prenatal Exposure to Endocrine Disruptors: A Developmental Etiology for Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is one of the most common and complex endocrinopathies among reproductive-age women. Polycystic ovary syndrome is characterized by symptomatology of oligomenorrhea and androgen excess, with or without presence of polycystic ovarian morphology. The etiology of PCOS is multifactorial, including genetic and environmental components. It has been previously established that prenatal androgen exposure results in a PCOS phenotype in experimental animal models and epidemiologic human studies. Investigators hypothesize that prenatal exposure to endocrine-disrupting chemicals (EDCs) may contribute to PCOS development. This review examines the emerging research investigating prenatal exposure to 3 major classes of EDCs-bisphenol A (BPA), phthalates, and androgenic EDCs-and the development of PCOS and/or PCOS-related abnormalities in humans and animal models. Highlights of this review are as follows: (1) In rodent studies, maternal BPA exposure alters postnatal development and sexual maturation;, (2) gestational exposure to dibutyl phthalate and di(2-ethylhexyl)phthalate results in polycystic ovaries and a hormonal profile similar to PCOS; and (3) androgenic EDCs, nicotine and 3,4,4'-trichlorocarbanilide, create a hyperandrogenic fetal environment and may pose a potential concern. In summary, prenatal exposure to EDCs may contribute to the altered fetal programming hypothesis and explain the significant variability in severity and presentation.

The 'Developmental Origins' Hypothesis: relevance to the obstetrician and gynecologist

The recognition of 'fetal origins of adult disease' has placed new responsibilities on the obstetrician, as antenatal care is no longer simply about ensuring good perinatal outcomes, but also needs to plan for optimal long-term health for mother and baby. Recently, it has become clear that the intrauterine environment has a broad and long-lasting impact, influencing fetal and childhood growth and development as well as future cardiovascular health, non-communicable disease risk and fertility. This article looks specifically at the importance of the developmental origins of ovarian reserve and ageing, the role of the placenta and maternal nutrition before and during pregnancy. It also reviews recent insights in developmental medicine of relevance to the obstetrician, and outlines emerging evidence supporting a proactive clinical approach to optimizing periconceptional as well as antenatal care aimed to protect newborns against long-term disease susceptibility.

The human placental proteome is affected by maternal smoking

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The effects of maternal smoking on the term placental proteome was studied.

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Maternal smoking significantly affected 18% of protein spots.

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Maternal smoking affects systems controlling the development and function of placenta.

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The observed placental changes may contribute to the lowered birth weights.

Detrimental effects of maternal smoking on the term placental proteome and steroid-metabolizing activities, and maternal hormone levels, were studied by using seven non-smoker and seven smoker placentae. Smoking significantly affected 18% of protein spots. The functional networks affected were i) cell morphology, cellular assembly and organization, cellular compromise (15 hits) and ii) DNA replication, recombination, and repair, energy production, nucleic acid metabolism (6 hits). Smoking significantly up-regulated such proteins as, SERPINA1, EFHD1 and KRT8; and down-regulated SERPINB2, FGA and HBB. Although maternal plasma steroids were not significantly altered, the catalytic activity of CYP1A1 was increased whereas CYP19A1 activity was reduced by smoking. Furthermore, transcript expression of CYP1A1 and CYP4B1 were induced while HSD17B2, NFKB and TGFB1 were repressed by smoking. The observed smoking induced wide-spread changes on placental proteome and transcript levels may contribute to the lowered birth weights of the new-born child and placenta.

The Mouse Fetal Ovary Has Greater Sensitivity Than the Fetal Testis to Benzo[a]pyrene-Induced Germ Cell Death

The polycyclic aromatic hydrocarbon pollutant benzo[a]pyrene (BaP) is a known developmental gonadotoxicant. However, the mechanism of BaP-induced germ cell death is unclear. We investigated whether exposure to BaP induces apoptotic germ cell death in the mouse fetal ovary or testis. Mouse fetal gonads were dissected at embryonic day 13.5 days postcoitum (dpc) and fixed immediately or cultured for 6, 24, 48, or 72 h with various concentrations of BaP (1-1000 ng/ml). Germ cells numbers, apoptosis, and proliferation were evaluated by immunostaining. Treatment of fetal ovaries with BaP for 72 h concentration-dependently depleted germ cells. Treatment with BaP elevated the expression of BAX protein at 6 h and activated downstream caspases-9 and -3 at 24 h in a concentration-dependent manner in germ cells of fetal ovaries. As a consequence, ovarian germ cell numbers were significantly and concentration-dependently decreased at 48 h. Pretreatment with z-VAD-fmk, a pan-caspase inhibitor, prior to exposure to 1000 ng/ml BaP prevented BaP-mediated ovarian germ cell death; there were no effects of BaP or z-VAD-fmk on germ cell proliferation. No significant effects of BaP exposure on caspase 3 activation or germ cell numbers were observed in fetal testes after 48 h of culture. Our findings show that BaP exposure increases caspase-dependent and BAX-associated germ cell apoptosis in the mouse fetal ovary, leading to germ cell depletion. In contrast, the cultured 13.5 dpc fetal testis is relatively resistant to BaP-induced germ cell death. This study provides a novel insight into molecular mechanisms by which BaP has direct gonadotoxicity in the mouse fetal ovary.

Female Reproductive Disorders, Diseases, and Costs of Exposure to Endocrine Disrupting Chemicals in the European Union

CONTEXT

A growing body of evidence suggests that endocrine-disrupting chemicals (EDCs) contribute to female reproductive disorders.

OBJECTIVE

To calculate the associated combined health care and economic costs attributable to specific EDC exposures within the European Union (EU).

DESIGN

An expert panel evaluated evidence for probability of causation using the Intergovernmental Panel on Climate Change weight-of-evidence characterization. Exposure-response relationships and reference levels were evaluated, and biomarker data were organized from carefully identified studies from the peer-reviewed literature to represent European exposure and approximate burden of disease as it occurred in 2010. Cost-of-illness estimation used multiple peer-reviewed sources.

SETTING, PATIENTS AND PARTICIPANTS AND INTERVENTION

Cost estimation was carried out from a societal perspective, ie, including direct costs (eg, treatment costs) and indirect costs such as productivity loss.

RESULTS

The most robust EDC-related data for female reproductive disorders exist for 1) diphenyldichloroethene-attributable fibroids and 2) phthalate-attributable endometriosis in Europe. In both cases, the strength of epidemiological evidence was rated as low and the toxicological evidence as moderate, with an assigned probability of causation of 20%–39%. Across the EU, attributable cases were estimated to be 56 700 and 145 000 women, respectively, with total combined economic and health care costs potentially reaching €163 million and €1.25 billion.

CONCLUSIONS

EDCs (diphenyldichloroethene and phthalates) may contribute substantially to the most common reproductive disorders in women, endometriosis and fibroids, costing nearly €1.5 billion annually. These estimates represent only EDCs for which there were sufficient epidemiologic studies and those with the highest probability of causation. These public health costs should be considered as the EU contemplates regulatory action on EDCs.

Human anogenital distance: an update on fetal smoke-exposure and integration of the perinatal literature on sex differences

STUDY QUESTION

Do sex and maternal smoking effects on human fetal anogenital distance (AGD) persist in a larger study and how do these data integrate with the wider literature on perinatal human AGD, especially with respect to sex differences?

SUMMARY ANSWER

Second trimester sex differences in AGD are broadly consistent with neonatal and infant measures of AGD and maternal cigarette smoking is associated with a temporary increase in male AGD in the absence of changes in circulating testosterone.

WHAT IS KNOWN ALREADY

AGD is a biomarker of fetal androgen exposure, a reduced AGD in males being associated with cryptorchidism, hypospadias and reduced penile length. Normative fetal AGD data remain partial and windows of sensitivity of human fetal AGD to disruption are not known.

STUDY DESIGN, SIZE, DURATION

The effects of fetal sex and maternal cigarette smoking on the second trimester (11–21 weeks of gestation) human fetal AGD were studied, along with measurement of testosterone and testicular transcripts associated with apoptosis and proliferation.

PARTICIPANTS/MATERIALS, SETTING METHODS

AGD, measured from the centre of the anus to the posterior/caudal root of penis/clitoris (AGD_app) was determined in 56 female and 70 male morphologically normal fetuses. These data were integrated with current literature on perinatal AGD in humans.

MAIN RESULTS AND THE ROLE OF CHANCE

At 11–13 weeks of gestation male fetal AGD_app was 61% (P< 0.001) longer than in females, increasing to 70% at 17–21 weeks. This sexual dimorphism was independent of growth characteristics (fetal weight, length, gonad weight). We confirmed that at 14–16 weeks of gestation male fetal AGD_app was increased 28% (P < 0.05) by in utero cigarette smoke exposure. Testosterone levels were not affected by smoking. To develop normative data, our findings have been integrated with available data from in vivo ultrasound scans and neonatal studies. Inter-study variations in male/female AGD differences lead to the conclusion that normalization and standardization approaches should be developed to enable confidence in comparing data from different perinatal AGD studies.

LIMITATIONS, REASONS FOR CAUTION

Sex differences, and a smoking-dependent increase in male fetal AGD at 14–16 weeks, identified in a preliminary study, were confirmed with a larger number of fetuses. However, human fetal AGD should, be re-assessed once much larger numbers of fetuses have been studied and this should be integrated with more detailed analysis of maternal lifestyle. Direct study of human fetal genital tissues is required for further mechanistic insights.

WIDER IMPLICATIONS OF THE FINDINGS

Fetal exposure to cigarette smoke chemicals is known to lead to reduced fertility in men and women. Integration of our data into the perinatal human AGD literature shows that more work needs to be done to enable reliable inter-study comparisons.

STUDY FUNDING/COMPETING INTEREST(S)

The study was supported by grants from the Chief Scientist Office (Scottish Executive, CZG/1/109 & CZG/4/742), NHS Grampian Endowments (08/02), the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement no 212885 and the Medical Research Council, UK (MR/L010011/1). The authors declare they have no competing interests, be it financial, personal or professional.

Long-term effects of methamphetamine exposure in adolescent mice on the future ovarian reserve in adulthood

Currently, there is an increasing prevalence of adolescent exposure to methamphetamine (MA). However, there is a paucity of information concerning the long-term impact of early exposure to MA upon female fertility and ovarian reserve. The aim of this study was to investigate the effect of long-term MA exposure in adolescents on their ovarian reserve in adulthood. Adolescent mice received intraperitoneal injections of MA (5mg/kg, three times per week) or saline from the 21st postnatal day for an 8 week period. Morphological, histological, biochemical, hormonal and ethological parameters were evaluated. An impaired ovarian reserve and vitality was found in the group treated with MA, manifesting in morphological-apparent mitochondrial damage, an activated apoptosis pathway in the ovarian tissue, a downward expression of ovarian anti-Mullerian hormone (AMH), a decreased number of primordial and growing follicles, an increased number of atretic follicles, and a depressed secretion of AMH, estradiol and progesterone from granulosa cells. However, no significant difference was noticed regarding the estrous cycle, the mating ability and the fertility outcome in the reproductive age of the mice after a period of non-medication. The present results confirmed that a long term exposure to methamphetamine in adolescent mice does have an adverse impact on their ovarian reserve, which indicates that such an early abuse of MA might influence the fertility lifespan of the female mouse.

Insight into the transgenerational effect of benzo[a]pyrene on bone formation in a teleost fish (Oryzias latipes)

Recent cross-generational studies in teleost fish have raised the awareness that high levels of benzo[a]pyrene (BaP) could affect skeletal integrity in the directly exposed F0 and their F1-F2. However, no further details were provided about the causes for abnormalities on the molecular and cellular level and the persistence of such sub-organismal impairments at the transgenerational scale (beyond F2). Adult Oryzias latipes were exposed to 1μg/L BaP for 21days. The F1-F3 were examined for skeletal deformities, histopathological alterations of vertebral bodies and differential expression of key genes of bone metabolism. Significant increase of dorsal-ventral vertebral compression was evident in ancestrally exposed larvae. Histopathological analysis revealed abnormal loss of notochord sheath, a lack of notochord epithelial integrity, reduced bone tissue and decreased osteoblast abundance. A significant downregulation of ATF4 and/or osterix and a high biological variability of COL10, coupled with a significant deregulation of SOX9a/b in the F1-F3 suggest that ancestral BaP exposure most likely perturbed chordoblasts, chondroblast and osteoblast differentiation, resulting in defective notochord sheath repair and rendering the vertebral column more vulnerable to compression. The present findings provide novel molecular and cellular insights into BaP-induced transgenerational bone impairment in the unexposed F3. From the ecological risk assessment perspective, BaP needs to be regarded as a transgenerational skeletal toxicant, which exerts a far-reaching impact on fish survival and fitness. Given that basic mechanisms of cartilage/bone formation are conserved between medaka and mammals, the results may also shed light on the potential transgenerational effect of BaP on the genesis of skeletal diseases in humans.

Association of serum levels of typical organic pollutants with polycystic ovary syndrome (PCOS): a case-control study

STUDY QUESTION

Is polycystic ovary syndrome (PCOS) associated with increased serum levels of typical organic pollutants?

SUMMARY ANSWER

PCOS in Han females from Northern China was significantly associated with elevated serum levels of pollutants, including polychlorinated biphenyls (PCBs), organochlorine pesticides and polycyclic aromatic hydrocarbons (PAHs).

WHAT IS KNOWN ALREADY

PCOS is arguably the most common endocrinopathy in females of reproductive age. The etiology of PCOS is thought to be multifactorial.

STUDY DESIGN, SIZE, DURATION

This was a preliminary case-control study undertaken at the Division of Reproductive Center, Peking University Third Hospital. Fifty participants affected by PCOS and 30 normal controls were recruited between August and October 2012 from Northern China. All participants were Han women.

PARTICIPANTS/MATERIALS, SETTING, METHODS

PCOS participants were diagnosed according to the 2003 Rotterdam criteria. The control participants were non-pregnant females unable to conceive solely due to male azoospermia. Serum levels of a wide range of organic pollutants, including PCBs, organochlorine pesticides, PAHs and more than 20 phenolic pollutants, were analyzed using gas chromatographic mass spectrometry.

MAIN RESULTS AND THE ROLE OF CHANCE

Serum levels of PCBs, pesticides and PAHs were significantly higher in the PCOS group than the control group. Concentrations of PCBs, p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) and PAHs in serum above median levels were associated with PCOS with odds ratios of 3.81 [95% confidence interval (CI), 1.45-10.0], 4.89 (95% CI, 1.81-13.2) and 2.39 (95% CI, 0.94-6.05), respectively. Partial least-squares-discriminant analysis (PLS-DA) confirmed that serum levels of organic pollutants were associated with PCOS, especially for p,p'-DDE and PCBs.

LIMITATIONS, REASONS FOR CAUTION

Some other possible covariates (e.g. dietary and income) were missed in this study, although education and occupation have been considered as an indicator of personal income. The PLS-DA model allowed a quasi-exposome analysis with over 60 kinds of typical organic pollutants; however, the possibility of other pollutants involved in the PCOS still could not be excluded.

WIDER IMPLICATIONS OF THE FINDINGS

Our study identified that bodily retention of environmental organic pollutants-including PCBs, pesticides (especially p,p'-DDE) and PAHs-was associated with PCOS.

STUDY FUNDING/COMPETING INTERESTS

This research was supported by the Ministry of Science and Technology of China Grants (973 program; 2014CB943203 and 2015CB553401), National Natural Science Foundation of China (21322705, 21190051, 41121004 and 81170538), National Key Technology R&D Program in the Twelve Five-Year Plan (2012BAI32B01) and the Collaborative Innovation Center for Regional Environmental Quality. There are no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

None. This is not a clinical trial.

Maternal Smoking Dysregulates Protein Expression in Second Trimester Human Fetal Livers in a Sex-Specific Manner

CONTEXT

Maternal smoking during pregnancy has adverse effects on the offspring (eg, increased likelihood of metabolic syndrome and infertility), which may involve alterations in fetal liver function.

OBJECTIVE

Our aim was to analyze, for the first time, the human fetal liver proteome to identify pathways affected by maternal smoking.

DESIGN

Fetal liver proteins extracted from elective second trimester pregnancy terminations (12-16 weeks of gestation) were divided in four balanced groups based on sex and maternal smoking.

SETTING AND PARTICIPANTS

Livers were collected from 24 morphologically normal fetuses undergoing termination for nonmedical reasons and analyzed at the Universities of Aberdeen and Glasgow.

MAIN OUTCOME MEASURES

Protein extracts were resolved by 2D-PAGE and analyzed with SameSpots software. Ingenuity pathway analysis was used to investigate likely roles of dysregulated proteins identified by tandem liquid chromatography/mass spectroscopy.

RESULTS

Significant expression differences between one or more groups (fetal sex and/or maternal smoking) were found in 22 protein spots. Maternal smoking affected proteins with roles in post-translational protein processing and secretion (ERP29, PDIA3), stress responses and detoxification (HSP90AA1, HSBP1, ALDH7A1, CAT), and homeostasis (FTL1, ECHS1, GLUD1, AFP, SDHA). Although proteins involved in necrosis and cancer development were affected in both sexes, pathways affecting cellular homeostasis, inflammation, proliferation, and apoptosis were affected in males and pathways affecting glucose metabolism were affected in females.

CONCLUSIONS

The fetal liver exhibits marked sex differences at the protein level, and these are disturbed by maternal smoking. The foundations for smoke-induced post-natal diseases are likely to be due to sex-specific effects on diverse pathways.

GDF9 is transiently expressed in oocytes before follicle formation in the human fetal ovary and is regulated by a novel NOBOX transcript

During human fetal ovary development, the process of primordial follicle formation is immediately preceded by a highly dynamic period of germ cell and somatic cell reorganisation. This is regulated by germ-cell specific transcription regulators, by the conserved RNA binding proteins DAZL and BOLL and by secreted growth factors of the TGFβ family, including activin βA: these all show changing patterns of expression preceding follicle formation. In mice, the transcription factor Nobox is essential for follicle formation and oocyte survival, and NOBOX regulates the expression of GDF9 in humans. We have therefore characterised the expression of GDF9 in relation to these known key factors during follicle formation in the human fetal ovary. mRNA levels of GDF9, BMP15 and NOBOX were quantified by qRT-PCR and showed dramatic increases across gestation. GDF9 protein expression was localised by immunohistochemistry to the same population of germ cells as those expressing activin βA prior to follicle formation but did not co-localise with either BOLL or DAZL. A novel NOBOX isoform was identified in fetal ovary that was shown to be capable of up-regulating the GDF9 promoter in reporter assays. Thus, during oogenesis in humans, oocytes go through a dynamic and very sharply demarcated sequence of changes in expression of these various proteins, even within individual germ cell nests, likely to be of major functional significance in determining selective germ cell survival at this key stage in ovarian development. Transcriptional variation may contribute to the range of age of onset of POI in women with NOBOX mutations.