Reproductive toxicity of combined effects of endocrine disruptors on human reproduction

Exploring the epigenetic impacts of atrazine in zebrafish: Unveiling mechanisms of neurotoxicity, reproductive toxicity, and implications for human health

Atrazine (ATZ), a widely utilized herbicide, is notable for its long environmental half-life and high solubility, raising significant concerns regarding its ecological and health impacts. While debates continue over its role as an endocrine disruptor, increasing attention has been directed toward its potential epigenetic effects. Utilizing the zebrafish model, a vertebrate with considerable genetic similarity to humans, provides valuable insights into how ATZ exposure may translate into human health risks. This review systematically examines the differential DNA methylation induced by ATZ's non-competitive inhibition of DNA methyltransferases, miRNA dysregulation resulting from mutations in miRNA processing enzymes, and the complex epigenetic interactions affecting histone modifications. Additionally, potential epigenetic biomarkers for ATZ exposure are proposed, which could advance targeted treatment strategies and improve health risk assessments. This synthesis of current understanding identifies knowledge gaps and guides future research towards a more comprehensive understanding of ATZ's epigenetic mechanisms.

Protective Role of Physical Activity and Antioxidant Systems During Spermatogenesis

Oxidative stress is a significant factor that contributes to male infertility and sperm dysfunction. In this condition, an increase in ROS production exceeds the body's antioxidant defenses, resulting in a decline in spermatozoa quality and fertilizing capacity. Furthermore, excessive ROS production has been linked to the promotion of genomic damage, lipid peroxidation, inflammation, altered enzyme activity, and ultimately, irreversible alterations, cell death, and a decline in seminal parameters associated with male infertility. It is established that physical activity (PA), acting on inflammatory parameters and improving antioxidant defense, can alleviate the negative effects caused by free radicals, offering numerous health benefits and positively influencing sperm quality. The objective of this review is to highlight the mechanisms of ROS production, the physiological and pathophysiological roles of ROS in relation to the male reproductive system, and recent knowledge on the impact of some protocols of PA on these systems and the molecular mechanisms involved.

Phenanthrene degradation by a flavoprotein monooxygenase from Phanerodontia chrysosporium

Phenanthrene (PHEN), a polycyclic aromatic hydrocarbon (PAH), is degraded by white-rot fungi like Phanerochaete chrysosporium (the fungus has been renamed as Phanerodontia chrysosporium). PHEN is metabolized by P. chrysosporium and transformed into various monohydroxylated and dihydroxylated products. These intermediates are further degraded by cleavage of the aromatic ring. However, the enzymes involved in PHEN conversion in P. chrysosporium remain largely unidentified. We aimed to identify and characterize the P. chrysosporium enzymes involved in the degradation of PHEN and its intermediates. Recombinant P. chrysosporium flavoprotein monooxygenase 11 (FPMO11), a homolog of the salicylate 1-monooxygenase from the naphthalene-degrading bacterium Pseudomonas putida G7, was overexpressed in Escherichia coli. FPMO11 catalyzes the oxidative decarboxylation of 1-hydroxy-2-naphthoate (1H2N) and 2-hydroxy-1-naphthoate (2H1N) to 1,2-dihydroxynaphthalene (1,2DHN). To the best of our knowledge, this is the first study to identify and characterize enzymes with 1H2N and 2H1N monooxygenase activities in members of the FPMO superfamily. Additionally, our search for a dioxygenase with the ability to catalyze the aromatic ring cleavage of 1,2DHN led to the identification of intradiol dioxygenase (IDD) 1 and IDD2 from P. chrysosporium, which catalyzes the ring cleavage of 1,2DHN. Thus, this study also identified, for the first time, intradiol 1,2DHN dioxygenase activity in members of the IDD superfamily. The findings highlight the unique substrate spectra of FPMO11 and IDDs, rendering them attractive candidates for biotechnological applications, especially mitigation of environmental and health risks associated with PAH pollution.IMPORTANCEPhenanthrene (PHEN), a polycyclic aromatic hydrocarbon (PAH), is a widely studied pollutant in environmental science and toxicology due to its presence in fossil fuels, tobacco smoke, and as a byproduct of incomplete combustion processes. White-rot fungi like P. chrysosporium can degrade PHEN through the production of extracellular oxidative enzymes. We investigated the properties of PHEN-degrading enzymes in P. chrysosporium, specifically one flavoprotein monooxygenase (FPMO11) and two intradiol dioxygenases (IDD1 and IDD2). Our findings indicate that the enzymes catalyze the aromatic ring cleavage of PHEN, using the intermediates as substrates, transforming them into less harmful and more biodegradable compounds. This could help reduce environmental pollution and mitigate health risks associated with PAH exposure. The potential of these enzymes for biotechnological applications is also highlighted, emphasizing their critical role in understanding PAH degradation by white-rot fungi.

Deleterious Effects of Caffeine Consumption on Reproductive Functions of Female Wistar Rats

OBJECTIVE

The deleterious effects of caffeine consumption on reproductive functions of female Wistar rats were investigated in this study.

METHODS

In this experimental study, 35 female Wistar rats (180-200g) were divided into 7 groups: Control, II-IV received oral caffeine (10, 20, and 40mg/kg/day respectively) for 21 days. V-VII received similar caffeine doses for 21 days, followed by a 21-day withdrawal period. The ovaries, fallopian tubes, and uteri were assessed for levels of malondialdehyde (MDA), nitric oxide (NO), reduced glutathione (GSH), superoxide dismutase (SOD), and catalase activity using spectrophotometry. Serum luteinizing hormone (LH), follicle-stimulating hormone (FSH), and estradiol levels were measured by ELISA. Organ histology was performed using microscopy. Statistical analysis employed ANOVA with significance at p<0.05.

RESULTS

Caffeine caused dose-dependent increases in MDA, NO, and catalase activity in the ovaries, fallopian tubes, and uteri which decreased upon withdrawal. GSH levels in the ovary and fallopian tubes decreased with caffeine intake but recovered during withdrawal. Caffeine reduced estradiol levels in a dose-dependent manner, its withdrawal led to reductions in serum LH at 20 and 40mg/kg/day and FSH at 40mg/kg/day. Histology revealed dose-dependent alterations in ovarian architecture with congested connective tissues. Caffeine caused sloughing of plicae in the muscularis of the fallopian tubes, degenerated epithelial layer in the uterus, and severe inflammation of the myometrial stroma cells that persisted during caffeine withdrawal.

CONCLUSIONS

Caffeine consumption adversely impacted the female reproductive functions of rats, altering hormonal balance and organ structure which persisted even after caffeine withdrawal.

Impact of Endocrine Disruptors on the Genitourinary Tract

Over the last decades, the human species has seen an increase in the incidence of pathologies linked to the genitourinary tract. Observations in animals have allowed us to link these increases, at least in part, to changes in the environment and, in particular, to an increasing presence of endocrine disruptors. These can be physical agents, such as light or heat; natural products, such as phytoestrogens; or chemicals produced by humans. Endocrine disruptors may interfere with the signaling pathways mediated by the endocrine system, particularly those linked to sex hormones. These factors and their general effects are presented before focusing on the male and female genitourinary tracts by describing their anatomy, development, and pathologies, including bladder and prostate cancer.

Female fertility preservation for family planning: a position statement of the Italian Society of Fertility and Sterility and Reproductive Medicine (SIFES-MR)

PURPOSE

This position statement by the Italian Society of Fertility and Sterility and Reproductive Medicine (SIFES-MR) aims to establish an optimal framework for fertility preservation outside the standard before oncological therapies. Key topics include the role of fertility units in comprehensive fertility assessment, factors impacting ovarian potential, available preservation methods, and appropriate criteria for offering such interventions.

METHODS

The SIFES-MR writing group comprises Italian reproductive physicians, embryologists, and scientists. The consensus emerged after a six-month period of meetings, including extensive literature review, dialogue among authors and input from society members. Final approval was granted by the SIFES-MR governing council.

RESULTS

Fertility counselling transitions from urgent to long-term care, emphasizing family planning. Age, along with ovarian reserve markers, is the primary predictor of female fertility. Various factors, including gynecological conditions, autoimmune disorders, and prior gonadotoxic therapies, may impact ovarian reserve. Oocyte cryopreservation should be the preferred method. Women 30-34 years old and 35-39 years old, without known pathologies impacting the ovarian reserve, should cryopreserve at least 12-13 and 15-20 oocytes to achieve the same chance of a spontaneous live birth they would have if they tried to conceive at the age of cryopreservation (63% and 52%, respectively in the two age groups).

CONCLUSIONS

Optimal fertility counselling necessitates a long-term approach, that nurtures an understanding of fertility, facilitates timely evaluation of factors that may affect fertility, and explores fertility preservation choices at opportune intervals.

Associations of exposure to bisphenol-A or parabens with markers of liver injury/function among US adults in NHANES 2011-2016

BACKGROUND

Bisphenol-A (BPA) and parabens are common endocrine-disrupting compounds (EDCs) that are used extensively in consumer products worldwide and are widely found in the environment.

OBJECTIVE

The purpose of this study was to comprehensively explore the correlations between urinary BPA/parabens levels and liver injury/function markers.

METHODS

In this cross-sectional study, we used National Health and Nutrition Examination Survey (NHANES) data from 2011 to 2016. The exposure variables were urinary BPA and four urinary parabens [methylparaben (MPB), ethylparaben (EPB), propylparaben (PPB), and butylparaben (BPB)], while the outcome variables were indicators of liver function/injury [alanine aminotransferase (ALT), aspartate aminotransferase (AST), AST/ ALT, albumin (ALB), total protein (TP), total bilirubin (TBIL), alkaline phosphatase (ALP), and the fibrosis-4 index (FIB-4)]. Multiple linear regression and weighted quantile sum (WQS) regression analyses were applied to explore the relationships between the individual/combined exposure variables and the liver injury/function indicators, respectively. Furthermore, stratified analysis was employed to detect the associations influenced by age and sex.

RESULTS

A total of 2,179 adults were eligible for the present analysis. Multivariate linear regression analysis revealed positive associations of EPB with AST, ALT, TP, and FIB-4 scores and negative associations of BPA with TP and ALB. The effects of urinary parabens on adverse outcomes in the liver (AST and ALT) were significant in the female and middle-aged subgroups. In addition, the WQS analysis revealed that the mixture of four compounds was negatively associated with ALB. BPA had the greatest effect on the serum ALB concentration (weight = 0.688).

IMPACT

Our present study provided novel evidence of significant associations between BPA or certain parabens and numerous markers of liver injury/function indicators. We found that higher urinary BPA concentrations were associated with worse liver function. Exposure to high EPB/PPB ratios was significantly associated with biomarkers of liver injury.

Reproductive and endocrine-disrupting toxicity of pyrogallol in catfish (Clariasgariepinus)

Endocrine disruptors are synthetic or natural chemicals that can agonize/antagonize hormone receptors or can interfere with the production and secretion of hormones, leading to altered tissue histology and physiology. Pyrogallol is a contaminant widely distributed in aquatic environments that presents health risks to both humans and animals. However, the potential for endocrine disruption by pyrogallol, particularly in fish, are lacking. The purpose of this study was to shed light on how pyrogallol may affect hormone signalling, histopathology, and reproductive outcomes in African catfish Clarias gariepinus. To investigate this, African catfish were exposed to one sublethal concentration of pyrogallol at either 0, 1, 5 or 10 mg/L for 15 days. We then assessed the effects of pyrogallol on the thyroid gland as well as the reproductive system by measuring sex hormone, seminal quality, gonadal histopathology, and histochemistry. Thyroid stimulating hormone and thyroxine showed notable decreases in catfish, and triiodothyronine was decreased with 10 mg/L pyrogallol. Unlike luteinizing hormone, follicle-stimulating hormone was significantly reduced in fish following exposure to pyrogallol relative to controls. Testosterone was also decreased in fish following pyrogallol exposure, whereas 17β-estradiol increased in catfish exposed to pyrogallol. Additionally, in response to pyrogallol toxicity, sperm quality indices, including count, spermatocrit, motility, and sperm viability were adversely affected in a concentration-dependent manner. Pyrogallol exposure also induced several changes in the gonad following exposure to 1, 5, or 10 mg/L. Deformed tubular structures, vacuolation, thickening of the basement membrane, hypertrophy of the seminiferous tubules, intense melanomacrophage localization, spermatozoa loss, and necrosis were all observed in the testes. In the ovary, atretic follicles, deteriorated mature oocytes, degenerated yolk globules, and an increase in perinucleolar oocytes were observed in catfish exposed to pyrogallol. These findings suggest that pyrogallol may act as endocrine disrupting substance in aquatic environments. Further research on the mechanisms by which pyrogallol impairs endocrine systems, particularly in fish, is recommended.

Lysosome dynamics during human endometrial stromal cells decidualization: effect of para-nonylphenol

During the process of decidualization, the stromal cells of the endometrium change dynamically to create a favorable environment for embryo implantation. Lysosome activity has often been associated with physiological changes in the endometrium during the preimplantation period and early pregnancy. In this study, the effect of para-nonylphenol (p-NP), an endocrine disruptor, on human immortalized endometrial stromal cells (tHESCs) was investigated. After exposure to p-NP (1 nM and 1 pM), the cells were examined for the decidualization markers connexin-43, insulin like growth factor binding protein 1 (IGFBP1), and prolactin. In addition, the effect of p-NP on lysosome biogenesis and exocytosis was investigated by examining the expression and localization of the transcription factor EB (TFEB) and that of the lysosomal-associated membrane protein 1 (LAMP-1). Finally, we evaluated the effect of p-NP on extracellular matrix (ECM) remodeling using a fibronectin assay. Our results showed that p-NP reduced the expression of prolactin protein, increased the nuclear localization of TFEB, and induced the increase and translocation of the lysosomal protein LAMP-1 to the membrane of tHESCs. The data indicate an impairment of decidualization and suggest an increase in lysosomal biogenesis and exocytosis, which is supported by the higher release of active cathepsin D by tHESCs. Given the importance of cathepsins in the processing and degradation of the ECM during trophoblast invasiveness and migration into the decidua, our results appear to be clear evidence of the negative effects of p-NP on endometrial processes that are fundamental to reproductive success and the establishment of pregnancy.NEW & NOTEWORTHY Endocrine disruptors, such as para-nonylphenol, affect the decidualization of human endometrial stromal cells with an impact on decidualization itself, lysosome biogenesis and exocytosis, and extracellular matrix remodeling. All these alterations may negatively impact embryo implantation with the success of reproduction and the establishment of pregnancy.

Per-polyfluoroalkyl substances (PFAS) as thyroid disruptors: is there evidence for multi-transgenerational effects?

INTRODUCTION

The environmental spread of pollutants has led to a persistent exposure of living beings to multiple chemicals, by now become ubiquitous in the surrounding environment. Environmental exposure to these substances has been reported to cause multi- and/or transgenerational health effects. Per- and Polyfluorinated Substances (PFAS) raise great concern, given their known effects both as endocrine disruptors and potential carcinogens. The multi/trans-generational effects of different endocrine disruptors have been investigated by several studies, and harmful effects observed also for PFAS.

AREAS COVERED

This review examines the current data on the multi-trans-generational effects of PFAS, with a focus on their impact on the thyroid axis. The aim is to determine if there is evidence of potential multi-trans-generational effects of PFAS on the thyroid and/or if more research is needed.

EXPERT OPINION

PFAS exposure impacts thyroid homeostasis and can cross the placental barrier. In addition PFAS have shown multi-transgenerational effects in laboratory experiences and animal models, but thyroid disruptive effects of PFAS were also investigated only in a small number of these studies. Efforts are needed to study the adverse effects of PFAS, as not all PFAS are regulated and removal strategies are still being developed.

House dust-derived mixtures of organophosphate esters alter the phenotype, function, transcriptome, and lipidome of KGN human ovarian granulosa cells

Organophosphate esters (OPEs), used as flame retardants and plasticizers, are present ubiquitously in the environment. Previous studies suggest that exposure to OPEs is detrimental to female fertility in humans. However, no experimental information is available on the effects of OPE mixtures on ovarian granulosa cells, which play essential roles in female reproduction. We used high-content imaging to investigate the effects of environmentally relevant OPE mixtures on KGN human granulosa cell phenotypes. Perturbations to steroidogenesis were assessed using ELISA and qRT-PCR. A high-throughput transcriptomic approach, TempO-Seq, was used to identify transcriptional changes in a targeted panel of genes. Effects on lipid homeostasis were explored using a cholesterol assay and global lipidomic profiling. OPE mixtures altered multiple phenotypic features of KGN cells, with triaryl OPEs in the mixture showing higher potencies than other mixture components. The mixtures increased basal production of steroid hormones; this was mediated by significant changes in the expression of critical transcripts involved in steroidogenesis. Further, the total-OPE mixture disrupted cholesterol homeostasis and the composition of intracellular lipid droplets. Exposure to complex mixtures of OPEs, similar to those found in house dust, may adversely affect female reproductive health by altering a multitude of phenotypic and functional endpoints in granulosa cells. This study provides novel insights into the mechanisms of actions underlying the toxicity induced by OPEs and highlights the need to examine the effects of human relevant chemical mixtures.

Synthetic human gonadal tissues for toxicology

The process of mammalian reproduction involves the development of fertile germ cells in the testis and ovary, supported by the surrounders. Fertilization leads to embryo development and ultimately the birth of offspring inheriting parental genome information. Any disruption in this process can result in disorders such as infertility and cancer. Chemical toxicity affecting the reproductive system and embryogenesis can impact birth rates, overall health, and fertility, highlighting the need for animal toxicity studies during drug development. However, the translation of animal data to human health remains challenging due to interspecies differences. In vitro culture systems offer a promising solution to bridge this gap, allowing the study of mammalian cells in an environment that mimics the physiology of the human body. Current advances on in vitro culture systems, such as organoids, enable the development of biomaterials that recapitulate the physiological state of reproductive organs. Application of these technologies to human gonadal cells would provide effective tools for drug screening and toxicity testing, and these models would be a powerful tool to study reproductive biology and pathology. This review focuses on the 2D/3D culture systems of human primary testicular and ovarian cells, highlighting the novel approaches for in vitro study of human reproductive toxicology, specifically in the context of testis and ovary.

Recent advances in toxicological research of di-(2-ethylhexyl)-phthalate: Focus on endoplasmic reticulum stress pathway

The plasticizer di-(2-ethylhexyl)-phthalate (DEHP) is the most significant phthalate in production, usage, and environmental occurrence. DEHP is found in products such as personal care products, furniture materials, cosmetics, and medical devices. DEHP is noncovalently bind with plastic therefore, repeated uses lead to leaching out of it. Exposure to DEHP plasticizers leads to toxicity in essential organs of the body through various mechanisms. The main objective of this review article is to focus on the DEHP-induced endoplasmic reticulum (ER) stress pathway implicated in the testis, brain, lungs, kidney, heart, liver, and other organs. Not only ER stress, PPAR-related pathways, oxidative stress and inflammation, Ca2+ homeostasis disturbances in mitochondria are also identified as the relative mechanisms. ER is involved in various critical functions of the cell such as Protein synthesis, protein folding, calcium homeostasis, and lipid peroxidation but, DEHP exposure leads to augmentation of misfolded/unfolded protein. This review complies with various recently reported DEHP-induced toxicity studies and some pharmacological interventions that have been shown to be effective through ER stress pathway. DEHP exposure does assess health risks and vulnerability to populations across the globe. This study offers possible targets and approaches for addressing various DEHP-induced toxicity.

Advances in understanding the reproductive toxicity of endocrine-disrupting chemicals in women

Recently, there has been a noticeable increase in disorders of the female reproductive system, accompanied by a rise in adverse pregnancy outcomes. This trend is increasingly being linked to environmental pollution, particularly through the lens of Endocrine Disrupting Chemicals (EDCs). These external agents disrupt natural processes of hormones, including synthesis, metabolism, secretion, transport, binding, as well as elimination. These disruptions can significantly impair human reproductive functions. A wealth of animal studies and epidemiological research indicates that exposure to toxic environmental factors can interfere with the endocrine system's normal functioning, resulting in negative reproductive outcomes. However, the mechanisms of these adverse effects are largely unknown. This work reviews the reproductive toxicity of five major environmental EDCs-Bisphenol A (BPA), Phthalates (PAEs), Triclocarban Triclosan and Disinfection Byproducts (DBPs)-to lay a foundational theoretical basis for further toxicological study of EDCs. Additionally, it aims to spark advancements in the prevention and treatment of female reproductive toxicity caused by these chemicals.

The single and mixed impacts of cadmium, cobalt, lead, and PAHs on systemic immunity inflammation index in male and female

Background

Studies on the association between mixed exposure to common pollutants such as cadmium (Cd), cobalt (Co), lead (Pb), and polycyclic aromatic hydrocarbons (PAHs) with Systemic Immune Inflammatory Index (SII), a novel hemocyte-based inflammatory marker, have not been reported. This study explored the relationship between co-exposure to Cd, Co, Pb, PAHs, and SII.

Methods

In this study, we used data from the National Health and Nutrition Examination Survey and enrolled adults with complete information on Cd, Co, Pb, PAHs, and SII. The linear regression was used to analyze the association of single pollutants with SII. Furthermore, a Bayesian Kernel Machine Regression analysis and a generalized weighted quantile sum regression analysis were used to analyze the association between mixed exposure to Cd, Co, Pb, and six PAHs and SII. We also separated males and females and analyzed the different effects of pollutants on SII, respectively.

Results

5,176 participants were included in the study. After adjusting for age, gender, race, education, smoking, drinking, physical activity, and sedentary, Cd, Co, 1-OHN, 2-OHN and 2-OHF were positive with SII in the total population. Compared with the 50th percentile, the joint effect of pollutants on SII was positive. In the total population, males, and females, the top contaminant with the highest effect weights on SII were Co, Cd, and 1-OHN, respectively. The result of interaction analysis showed that the low concentrations of Cd had an elevation effect on SII in males.

Conclusion

This study found a positive association of mixed exposure to Cd, Co, Pb, and six PAHs with SII, which occurred mainly in females.

Decrease in Sperm Parameters in the 21st Century: Obesity, Lifestyle, or Environmental Factors? An Updated Narrative Review

Semen quality represents a compelling factor for fertility, and delineating the normal values has proven difficult. In the last four decades, several authors have reported a noticeable decline in sperm parameters. Also, studies investigating 'time to pregnancy' have shown that fecundity begins to be reduced when sperm numbers decrease below 30 million, even though according to the 6th edition of the WHO manual, the normal value is currently 16 million/mL or 39 million per ejaculate. There exists sufficient data to suggest a decline in sperm counts over time, even though the clear reason for this adverse trend is not well established, but some associations have been hypothesised, such as maternal smoking during pregnancy. Additional potential factors have yet to be fully illustrated but involve poor diet, increased obesity, and exposure to environmental toxins. Moreover, the change in environmental conditions and more common exposure to endocrine-disrupting chemicals (EDCs), such as pesticides and herbicides, as well as bisphenol A, phthalates, polychlorinated biphenyls, and heavy metals, starting from prenatal life and continuing into adulthood, may exhibit probable features explaining the reduction in sperm parameters. Therefore, the main goal of this narrative review is to furnish an overview of the possible effects of exposure to EDCs on testicular function and spermatogenesis and, also, to summarise the evidence regarding a decrease in sperm quality and examine its potential consequences.

Environmental and Genetic Traffic in the Journey from Sperm to Offspring

Recent advancements in the understanding of how sperm develop into offspring have shown complex interactions between environmental influences and genetic factors. The past decade, marked by a research surge, has not only highlighted the profound impact of paternal contributions on fertility and reproductive outcomes but also revolutionized our comprehension by unveiling how parental factors sculpt traits in successive generations through mechanisms that extend beyond traditional inheritance patterns. Studies have shown that offspring are more susceptible to environmental factors, especially during critical phases of growth. While these factors are broadly detrimental to health, their effects are especially acute during these periods. Moving beyond the immutable nature of the genome, the epigenetic profile of cells emerges as a dynamic architecture. This flexibility renders it susceptible to environmental disruptions. The primary objective of this review is to shed light on the diverse processes through which environmental agents affect male reproductive capacity. Additionally, it explores the consequences of paternal environmental interactions, demonstrating how interactions can reverberate in the offspring. It encompasses direct genetic changes as well as a broad spectrum of epigenetic adaptations. By consolidating current empirically supported research, it offers an exhaustive perspective on the interwoven trajectories of the environment, genetics, and epigenetics in the elaborate transition from sperm to offspring.