Endocrine-disrupting chemicals and uterine fibroids

Associations between per- and polyfluoroalkyl substances (PFAS) and female sexual function in a preconception cohort

BACKGROUND

Female sexual function is important for sexual well-being, general health, fertility, and relationship satisfaction. Distressing impairments in sexual function, clinically recognized as female sexual dysfunction (FSD), can manifest as issues with interest/desire, arousal, orgasm, and pain during vaginal penetration. Some evidence suggests that exposure to endocrine-disrupting chemicals may adversely affect female sexual function, but associations for per- and polyfluoroalkyl substances (PFAS) have not been previously evaluated.

OBJECTIVE

We investigated associations between serum PFAS concentrations and female sexual function among U.S. pregnancy planners.

METHODS

We used cross-sectional data from participants from Pregnancy Study Online (PRESTO), a prospective preconception cohort study. Participants reported sexual function and distress at baseline on two validated measures: a modified version of the Female Sexual Function Index-6 (FSFI-6) and the Female Sexual Distress Scale (FSDS). We quantified PFAS serum concentrations in samples collected in the preconception period (i.e., at baseline) using solid phase extraction-high performance liquid chromatography-isotope-dilution-mass spectrometry. Participants reported sociodemographic information on structured baseline questionnaires. We included 78 participants with complete PFAS and sexual function data and fit multivariable linear regression models to estimate mean differences in FSFI-6 scores (β) or percent differences (%) in FSDS scores per interquartile range (IQR) increase in PFAS concentrations, adjusting for age, annual household income, years of education, parity, and body mass index. We further investigated effect measure modification by parity (parous vs. nulliparous) in stratified models.

RESULTS

An IQR increase in perfluorohexanesulfonic acid was associated with a 1.0-point decrease (95% CI = -1.8, -0.1) in reported FSFI-6 scores, reflecting poorer sexual function. PFAS were consistently associated with lower FSFI-6 scores among parous participants. PFAS were also associated, though imprecisely, with greater sexual distress.

CONCLUSION

Some PFAS were associated with poorer sexual function among U.S. pregnancy planners, but future studies are needed to clarify the extent to which PFAS influences female sexual health.

Hair Straightener Use in Relation to Prevalent and Incident Fibroids in the Sister Study with a Focus on Black Women

BACKGROUND

Uterine fibroids disproportionately affect Black women, and exposure to chemicals from hair relaxers or straighteners ("straighteners") may contribute to fibroid development.

OBJECTIVES

We examined the association between straightener use and prevalent young-onset uterine fibroids (diagnosed before age 36 y), as well as incident fibroids (diagnosed age 36-60 y), with a focus on Black women. We also examined differences in associations across birth cohorts as proxies for formulation changes.

METHODS

Data from 4,162 Black women in the Sister Study, a prospective cohort of women 35-74 y of age (enrolled 2003-2009), were analyzed. We used logistic regression to estimate odds ratios (ORs) for the association of straightener use at 10-13 y of age and self-reported young-onset fibroids. We used Cox regression to assess hazard ratios (HRs) for straightener use (age 10-13 y and in 12 months before enrollment) and incident fibroids among 779 premenopausal Black women. Similar analyses were conducted in 40,782 non-Hispanic White women.

RESULTS

Over 70% of Black women used straighteners. In comparison with no use, any [OR = 1.15 ; 95% confidence interval (CI): 0.96, 1.36] and frequent use (OR = 1.18 ; 95% CI: 0.99, 1.42) of straighteners at 10-13 y of age were associated with young-onset fibroids. This association was most apparent among those born between 1928 and 1945 (OR = 1.78 ; 95% CI: 1.15, 2.74) and 1965-1974 (OR = 1.64 ; 95% CI: 0.82, 3.29). Fibroid incidence from 36 to 60 y of age was modestly associated with use of straighteners at 10-13 y of age [hazard ratio ( HR ) = 1.14 ; 95% CI: 0.81, 1.63] and in the 12 months prior to enrollment (HR = 1.32 ; 95% CI: 0.88, 2.00). Among non-Hispanic White women, straightener use at 10-13 y of age was similarly associated with young-onset fibroids (OR = 1.23 ; 95% CI: 1.03, 1.47) despite lower use (≤ 5 % ) of straighteners. Sensitivity analyses indicated a potential for bias due to fibroid misclassification, with an overestimation of the effect likely if nulliparous women or women from households with lower education reported their fibroid status less accurately.

DISCUSSION

Hair straightener use may be positively associated with fibroid risk. https://doi.org/10.1289/EHP14493.

The impact of Bisphenol-A on human reproductive health

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

The Association of Vitamin D with Uterine Fibroids in Premenopausal Patients: A Systematic Review and Meta-Analysis

OBJECTIVE

This study aims to consolidate existing literature regarding the association between vitamin D and uterine fibroid presence and growth.

DATA SOURCES

A comprehensive search across databases including Medline, Embase, CINAHL, Web of Science, ClinicalTrials.gov, and grey literature was conducted from inception to February 2023, using relevant keywords. Authors were contacted for unpublished data.

STUDY SELECTION

From 9931 studies screened based on title and abstract, those evaluating serum vitamin D levels or vitamin D treatment effects, using ultrasonography for diagnosis, and involving at least 25 premenopausal participants were included. Case reports, case series, and reviews were excluded.

DATA EXTRACTION AND SYNTHESIS

Data were extracted using a predefined form. Methodological quality was assessed through the Newcastle-Ottawa Scale and the Risk of Bias-2 tools. Evidence quality was evaluated using Grading of Recommendations Assessment, Development, and Evaluation. Data from 3 randomised controlled trials (n = 328) and 23 observational studies (n = 5650) were meta-analyzed via random-effects modelling. Patients receiving oral vitamin D supplementation had a significantly different change in fibroid size (standardized mean difference -5.7%; CI -10.63 to -0.76, P = 0.02, I2 = 99%), as measured by the percentage change in diameter or volume, compared to controls, over the span of 2-6 months. Those receiving supplementation had vitamin D insufficiency; regimens varied between 50 000 IU weekly for 12 weeks, 50 000 IU weekly for 8 weeks, and 50 000 IU biweekly for 10 weeks. Patients with fibroids exhibited lower serum vitamin D concentrations (mean difference -5.50 ng/mL; CI 6.99 to -4.01, P < 0.001, I2 = 87%) and higher odds of vitamin D deficiency (OR 3.71; CI 1.90-7.24, P < 0.001, I2 = 80%).

CONCLUSION

This review underscores the potential of vitamin D in mitigating fibroid development and growth. While promising, further research is warranted to optimise dosage and treatment duration, potentially offering a non-invasive solution for at-risk patients. Continued exploration of vitamin D's role in fibroid treatment is encouraged.

Phthalate exposure as a hidden risk factor for uterine leiomyoma in adult women: Accumulated evidence from observational studies

BACKGROUND

There is evidence that exposure to phthalate in women may increase the risk of uterine leiomyomas. Whereas, the association between exposure to phthalate and the incidence of uterine leiomyoma remained inconclusive.

METHODS

A meta-analysis was performed to evaluate their relationship. Literature eligible for inclusion was found in PubMed, EMBASE, Web of Science, and WanFang Medical Database. Pooled odds ratio (OR) with 95 % confidence interval (CI) was calculated to assess the risk for effect estimate for each phthalate.

RESULTS

A total of fourteen observational studies with 5777 subjects of adult women were included in this study. In the pooled analysis, we found an elevated risk of uterine leiomyoma among women who were exposed to higher levels of di-2-ethylhexyl phthalate (DEHP) (OR 1.61, 95 % CI: 1.18-2.20), as estimated indirectly from the molar summation of its urinary metabolite concentrations. In addition, a positive association was observed between the occurrence of uterine leiomyoma and exposure to low molecular weight phthalate mixture (OR 1.08, 95 % CI: 1.00-1.15), as well as high molecular weight phthalate mixture (OR 1.08, 95 % CI: 1.01-1.15), as quantified by integrating the effect estimates of individual metabolite from each study. Urinary levels of DEHP metabolites, monobenzyl phthalate, mono-(3-carboxypropyl) phthalate, mono-isobutyl phthalate, mono-n-butyl phthalate, monoethyl phthalate, and monomethyl phthalate were not appreciably correlated with the risk of uterine leiomyoma.

CONCLUSION

Our results indicated that exposure to DEHP, and co-exposure to high or low molecular weight phthalate mixture might be potential risk factors for uterine leiomyoma in adult women. Owing to the indirect estimation of association, when interpreting these findings, cautions should be taken.

Menstrual products: culprits or bystanders in endometriosis and adenomyosis pathogenesis?

Products that may reduce menstrual flow from the endometrial cavity to the vagina (i.e. tampons and menstrual cups) could facilitate retrograde menstruation and the spillage of blood into the myometrium, two mechanisms which could be major determinants in endometriosis and adenomyosis pathogenesis. The aim of this narrative review is to summarize the evidence regarding the mechanical role menstrual products may have in the pathogenesis of these two conditions. Evidence in this regard is inconclusive. While Darrow and colleagues observed that 14 or more years of tampon use were associated with endometriosis (OR 3.6; 95% CI, 1.04-13.5); in Meaddough and colleagues' retrospective study, the percentage of women using pads only was significantly higher among those with endometriosis than among those without the condition (31% vs 22%). Three further groups failed to find an association between endometriosis/adenomyosis and any type of menstrual product. The only case that may be considered as a sort of proof-of-concept of the association between products potentially reducing anterograde menstrual flow and endometriosis was reported by Spechler and colleagues, who described the case of a 41 year-old who developed endometriosis after having used a menstrual cup on a regular basis. However, the number of studies on the subject is scarce, study populations are exiguous and a greater attention to temporality of endometriosis onset in relation to when women started habitually using a specific menstrual product is needed. Confounding variables including type and quantity of endocrine disruptors contained in menstrual products should also be addressed. At the present moment, no recommendation can be provided on the safety of one type of menstrual product compared to another.

Impact of lifestyle and dietary modifications for endometriosis development and symptom management

PURPOSE OF REVIEW

Management of endometriosis is often complex and poorly studied. Patients with endometriosis have interest in how their lifestyle may affect their diagnosis. Self-management and lifestyle changes are often used as adjunct therapy, but best practices are not concrete in treatment guidelines.

RECENT FINDINGS

Lifestyle impact on endometriosis and possible self-management treatment therapies are reviewed. Overall, there is a need for future studies in all topics. Data suggest a link between endocrine-disrupting chemicals (EDCs), particularly persistent EDCs, and endometriosis. More work is needed to isolate and quantify exposures and explore their connection to endometriosis in order to provide guidance for clinical practice recommendations. There is insufficient evidence to support a superior diet for management of endometriosis; however, the Mediterranean diet may have the most benefit without nutrition concerns. Exercise may be another tool to improve endometriosis symptoms, but once again data are limited and best type and frequency is not well studied. Best evidence supports body-mind practices such as yoga, although new evidence suggests benefit from a holistic combination of several types of exercises.

SUMMARY

Overall, data on lifestyle effects and associated therapies are limited. Future high-quality studies are needed to guide practice.

Chemicals in menstrual products: A systematic review

BACKGROUND

From menarche until menopause, the average menstruator will use over 11 000 tampons or sanitary pads. Vaginal and vulvar tissue is highly permeable, and chemicals are absorbed without undergoing first-pass metabolism.

OBJECTIVES

To conduct a review of the literature to determine exposure to environmental chemicals in menstrual products.

SEARCH STRATEGY

This review identified 15 papers over the past 10 years.

SELECTION CRITERIA

Papers that measured chemicals in menstrual products and that measured human biomarkers of chemical exposure were included. Papers had to also be available in English.

DATA COLLECTION AND ANALYSIS

Reviewers assessed the articles and data provided. Multiple chemical groups were found.

MAIN RESULTS

Phthalates, volatile organic compounds, parabens, environmental phenols, fragrance chemicals, dioxins and dioxin-like compounds were detected in menstrual products. Research gaps were identified, including the lack of studies on newer products such as menstrual underwear and cups/discs. In addition to measuring chemicals in these products, future research should focus on clarifying the exposure per menstrual cycle to these chemicals to understand how menorrhagia and cycle length influence exposure from menstrual products.

CONCLUSION

Menstrual products contained measurable levels of a range of endocrine disrupting chemicals including phthalates, phenols and parabens. This reflects a potentially important route of exposure to chemicals that can impact women's reproductive health.

Family History and Uterine Fibroid Development in Black and African American Women

Importance

Uterine fibroids are an understudied condition, with earlier onset in Black than White women. Prior studies of the importance of family history on fibroid development are limited by reliance on hospital-based participant selection, poorly defined measures of family history, and nonsystematic fibroid assessment.

Objective

To examine whether family history is a risk factor for fibroid development using prospective ultrasonography data to identify incident fibroids and measure fibroid growth and standardized methods to ascertain family history.

Design, Setting, and Participants

This prospective community cohort of Black and African American women from the Detroit, Michigan, area was conducted from January 1, 2010, to December 31, 2018, using 4 standardized ultrasonographic examinations during 5 years to detect fibroids 0.5 cm or larger in diameter and measure fibroid growth. Data analysis was performed between May 2022 and January 2024.

Exposures

Maternal fibroid history data were gathered directly from participants' mothers when possible (1425/1628 [88%]), and 2 exposure variables were created: maternal history of fibroids (diagnosed vs not diagnosed) and age at maternal fibroid diagnosis (20-29, 30-39, or ≥40 years vs not diagnosed).

Main Outcomes and Measures

Fibroid incidence was assessed using multivariable Cox proportional hazards regression models; fibroid growth was calculated as change in log-volume per 18 months for fibroids matched at successive ultrasonograms.

Results

A total of 1610 self-identified Black and/or African American women aged 23 to 35 years (mean [SD] age, 29.2 [3.4] years) with no prior clinical diagnosis of fibroids at enrollment were available for analysis. Of 1187 fibroid-free participants at enrollment, 442 (37%) had mothers who were diagnosed with fibroids. Compared with participants without a maternal history of fibroids, those reporting maternal history had an adjusted hazard ratio (AHR) of 1.21 (95% CI, 0.96-1.52). Risk was strongest in those whose mothers were diagnosed at a younger age (20-29 years: AHR, 1.56; 95% CI, 1.11-2.21; 30-39 years: AHR, 1.03; 95% CI, 0.71-1.49; ≥40 years: AHR, 1.11; 95% CI, 0.81-1.52; P = .053 for trend). Fibroid growth rates were higher when mothers were diagnosed with fibroids vs not diagnosed (8.0% increased growth; 95% CI, -1.2% to 18.0%).

Conclusions and Relevance

In this prospective cohort study, results supported maternal history of fibroids as a risk factor for incident fibroids, especially when mothers were diagnosed at a younger age. Maternal history was also associated with increased fibroid growth. Asking patients about their family history of fibroids could encourage patient self-advocacy and inform care.

Racial disparity in uterine leiomyoma: new insights of genetic and environmental burden in myometrial cells

Uterine leiomyoma (LM), also known as uterine fibroids, are common gynecological tumors and can reach a prevalence of 70% among women by the age of 50 years. Notably, the LM burden is much higher in Black women with earlier onset, a greater tumor number, size, and severity compared to White women. Published knowledge shows that there are genetic, environmental, and lifestyle-based risk factors associated with racial disparity for LM. Significant strides have been made on genomic, epigenomic, and transcriptomic data levels in Black and White women to elucidate the underlying pathomolecular reasons of racial disparity in LM development. However, racial disparity of LM remains a major area of concern in gynecological research. This review highlights risk factors of LM and their role in different races. Furthermore, we discuss the genetics and uterine myometrial microenvironment in LM development. Comparative findings revealed that a major racial difference in the disease is linked to myometrial oxidative burden and altered ROS pathways which is relevant to the oxidized guanine in genomic DNA and MED12 mutations that drive the LM genesis. Considering the burden and morbidity of LM, we anticipate that this review on genetic risk and myometrial microenvironment will strengthen understanding and propel the growth of research to address the racial disparity of LM burden.

Evidence-Based Approach for Secondary Prevention of Uterine Fibroids (The ESCAPE Approach)

Uterine fibroids (UFs) are common tumors in women of reproductive age. It is imperative to comprehend UFs' associated risk factors to facilitate early detection and prevention. Simple relying on surgical/pharmacological treatment of advanced disease is not only highly expensive, but it also deprives patients of good quality of life (QOL). Unfortunately, even if the disease is discovered early, no medical intervention is traditionally initiated until the disease burden becomes high, and only then is surgical intervention performed. Furthermore, after myomectomy, the recurrence rate of UFs is extremely high with the need for additional surgeries and other interventions. This confused approach is invasive and extremely costly with an overall negative impact on women's health. Secondary prevention is the management of early disease to slow down its progression or even halt it completely. The current approach of watchful observation for early disease is considered a major missed opportunity in the literature. The aim of this article is to present an approach named the ESCAPE (Evidence-Based Approach for Secondary Prevention) of UF management. It comprises simple, inexpensive, and safe steps that can arrest the development of UFs, promote overall reproductive health, decrease the number of unnecessary surgeries, and save billions of health care systems' dollars worldwide.

Developmental reprogramming of myometrial stem cells by endocrine disruptor linking to risk of uterine fibroids

BACKGROUND

The stage, when tissues and organs are growing, is very vulnerable to environmental influences, but it's not clear how exposure during this time causes changes to the epigenome and increases the risk of hormone-related illnesses like uterine fibroids (UFs).

METHODS

Developmental reprogramming of myometrial stem cells (MMSCs), the putative origin from which UFs originate, was investigated in vitro and in the Eker rat model by RNA-seq, ChIP-seq, RRBS, gain/loss of function analysis, and luciferase activity assays.

RESULTS

When exposed to the endocrine-disrupting chemical (EDC) diethylstilbestrol during Eker rat development, MMSCs undergo a reprogramming of their estrogen-responsive transcriptome. The reprogrammed genes in MMSCs are known as estrogen-responsive genes (ERGs) and are activated by mixed lineage leukemia protein-1 (MLL1) and DNA hypo-methylation mechanisms. Additionally, we observed a notable elevation in the expression of ERGs in MMSCs from Eker rats exposed to natural steroids after developmental exposure to EDC, thereby augmenting estrogen activity.

CONCLUSION

Our studies identify epigenetic mechanisms of MLL1/DNA hypo-methylation-mediated MMSC reprogramming. EDC exposure epigenetically targets MMSCs and leads to persistent changes in the expression of a subset of ERGs, imparting a hormonal imprint on the ERGs, resulting in a "hyper-estrogenic" phenotype, and increasing the hormone-dependent risk of UFs.

Epigenetic Modulation of Inflammatory Pathways in Myometrial Stem Cells and Risk of Uterine Fibroids

The period during which tissue and organ development occurs is particularly vulnerable to the influence of environmental exposures. However, the specific mechanisms through which biological pathways are disrupted in response to developmental insults, consequently elevating the risk of hormone-dependent diseases, such as uterine fibroids (UFs), remain poorly understood. Here, we show that developmental exposure to the endocrine-disrupting chemical (EDC), diethylstilbestrol (DES), activates the inflammatory pathways in myometrial stem cells (MMSCs), which are the origin of UFs. Significantly, the secretome of reprogrammed MMSCs enhances the expression of critical inflammation-related genes in differentiated myometrial cells through the paracrine mechanism, which amplifies pro-inflammatory and immune suppression signaling in the myometrium. The expression of reprogrammed inflammatory responsive genes (IRGs) is driven by activated mixed-lineage leukemia protein-1 (MLL1) in MMSCs. The deactivation of MLL reverses the reprogramming of IRG expression. In addition, the inhibition of histone deacetylases (HDACs) also reversed the reprogrammed IRG expression induced by EDC exposure. This work identifies the epigenetic mechanisms of MLL1/HDAC-mediated MMSC reprogramming, and EDC exposure epigenetically targets MMSCs and imparts an IRG expression pattern, which may result in a "hyper-inflammatory phenotype" and an increased hormone-dependent risk of UFs later in life.

A View on Uterine Leiomyoma Genesis through the Prism of Genetic, Epigenetic and Cellular Heterogeneity

Uterine leiomyomas (ULs), frequent benign tumours of the female reproductive tract, are associated with a range of symptoms and significant morbidity. Despite extensive research, there is no consensus on essential points of UL initiation and development. The main reason for this is a pronounced inter- and intratumoral heterogeneity resulting from diverse and complicated mechanisms underlying UL pathobiology. In this review, we comprehensively analyse risk and protective factors for UL development, UL cellular composition, hormonal and paracrine signalling, epigenetic regulation and genetic abnormalities. We conclude the need to carefully update the concept of UL genesis in light of the current data. Staying within the framework of the existing hypotheses, we introduce a possible timeline for UL development and the associated key events—from potential prerequisites to the beginning of UL formation and the onset of driver and passenger changes.

Prevention of Uterine Fibroids: molecular mechanisms and potential clinical application

Uterine fibroids (UFs; leiomyoma) are the most common benign neoplastic threat to women worldwide, exacting an immense personal burden on female health and a monetary expense to the healthcare system estimated in the hundreds of billions of dollars every year globally. With no long-term non-invasive treatment option currently available to treat UFs, deeper insights regarding tumor etiology are the key for developing newer therapies. Accordingly, in this review, we discuss new mechanistic paradigm to explain UF tumor development through an exquisite model involving developmental reprogramming of myometrial stem cells due to early life endocrine disruptors exposure, inflammation, fibrosis, DNA damage, and eventually tissue stiffness. Further, we propose to utilize shear wave elastography as a potential screening tool for the early identification of women at risk for developing UFs who can benefit from several simple preventive strategies, including the consumption of natural compounds such as vitamin D and green tea as a safe fertility friendly non-hormonal modality to delay or even arrest or reverse UF progression.

Effects of bisphenol A on uterine leiomyoma: In vitro and in vivo evaluation with mechanistic insights related to XBP1

The incidence rate of human uterine leiomyomas is over 70% in the women of childbearing age, which has caused serious health and financial burden. Our previous study confirmed that Bisphenol A (BPA)，representative environmental estrogen, promoted the proliferation of human uterine leiomyomas and up-regulated the expression of cell proliferation-related genes. In this study, by combining ChIP-seq and RNA-seq, it was shown that after BPA intervention, H3K27ac modification levels and gene expression levels were altered in uterine leiomyomas cells. Moreover experimental verification found that BPA can regulate ITGA2 through the transcription factor XBP1, activate the downstream PI3K/AKT signaling pathway, eventually promote the proliferation of uterine leiomyomas. The present study provides new insights into the pathogenesis associated with exposure to BPA and other endocrine disruptors with similar effects by defining XBP1 as an important regulator, and which may act as an intervention and treatment target for uterine leiomyomas.

Mono-(2-ethyl-5-hydroxyhexyl) phthalate promotes uterine leiomyoma cell survival through tryptophan-kynurenine-AHR pathway activation

Uterine leiomyoma is the most common tumor in women and causes severe morbidity in 15 to 30% of reproductive-age women. Epidemiological studies consistently indicate a correlation between leiomyoma development and exposure to endocrine-disrupting chemical phthalates, especially di-(2-ethylhexyl) phthalate (DEHP); however, the underlying mechanisms are unknown. Here, among the most commonly encountered phthalate metabolites, we found the strongest association between the urine levels of mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), the principal DEHP metabolite, and the risk of uterine leiomyoma diagnosis (n = 712 patients). The treatment of primary leiomyoma and smooth muscle cells (n = 29) with various mixtures of phthalate metabolites, at concentrations equivalent to those detected in urine samples, significantly increased cell viability and decreased apoptosis. MEHHP had the strongest effects on both cell viability and apoptosis. MEHHP increased cellular tryptophan and kynurenine levels strikingly and induced the expression of the tryptophan transporters SLC7A5 and SLC7A8, as well as, tryptophan 2,3-dioxygenase (TDO2), the key enzyme catalyzing the conversion of tryptophan to kynurenine that is the endogenous ligand of aryl hydrocarbon receptor (AHR). MEHHP stimulated nuclear localization of AHR and up-regulated the expression of CYP1A1 and CYP1B1, two prototype targets of AHR. siRNA knockdown or pharmacological inhibition of SLC7A5/SLC7A8, TDO2, or AHR abolished MEHHP-mediated effects on leiomyoma cell survival. These findings indicate that MEHHP promotes leiomyoma cell survival by activating the tryptophan-kynurenine-AHR pathway. This study pinpoints MEHHP exposure as a high-risk factor for leiomyoma growth, uncovers a mechanism by which exposure to environmental phthalate impacts leiomyoma pathogenesis, and may lead to the development of novel druggable targets.

Pre-clinical models to study abnormal uterine bleeding (AUB)

Abnormal Uterine Bleeding (AUB) is a common debilitating condition that significantly reduces quality of life of women across the reproductive age span. AUB creates significant morbidity, medical, social, and economic problems for women, their families, workplace, and health services. Despite the profoundly negative effects of AUB on public health, advancement in understanding the pathophysiology of AUB and the discovery of novel effective therapies is slow due to lack of reliable pre-clinical models. This review discusses currently available laboratory-based pre-clinical scientific models and how they are used to study AUB. Human and animal in vitro, ex vivo, and in vivo models will be described along with advantages and limitations of each method.

A transcriptome-wide association study of uterine fibroids to identify potential genetic markers and toxic chemicals

Uterine fibroid is one of the most prevalent benign tumors in women, with high socioeconomic costs. Although genome-wide association studies (GWAS) have identified several loci associated with uterine fibroid risks, they could not successfully interpret the biological effects of genomic variants at the gene expression levels. To prioritize uterine fibroid susceptibility genes that are biologically interpretable, we conducted a transcriptome-wide association study (TWAS) by integrating GWAS data of uterine fibroid and expression quantitative loci data. We identified nine significant TWAS genes including two novel genes, RP11-282O18.3 and KBTBD7, which may be causal genes for uterine fibroid. We conducted functional enrichment network analyses using the TWAS results to investigate the biological pathways in which the overall TWAS genes were involved. The results demonstrated the immune system process to be a key pathway in uterine fibroid pathogenesis. Finally, we carried out chemical–gene interaction analyses using the TWAS results and the comparative toxicogenomics database to determine the potential risk chemicals for uterine fibroid. We identified five toxic chemicals that were significantly associated with uterine fibroid TWAS genes, suggesting that they may be implicated in the pathogenesis of uterine fibroid. In this study, we performed an integrative analysis covering the broad application of bioinformatics approaches. Our study may provide a deeper understanding of uterine fibroid etiologies and informative notifications about potential risk chemicals for uterine fibroid.

Personal Care and Household Cleaning Product Use among Pregnant Women and New Mothers during the COVID-19 Pandemic

This study examined product use among pregnant women and new mothers in New York City during the COVID-19 pandemic (July 2020-June 2021). Women reported use of personal care and household cleaning products within the previous month, changes in antibacterial product use, receipt of healthcare provider advice, and opinions on environmental chemicals (n = 320). On average, women used 15 personal care products and 7 household cleaning products. Non-Hispanic Black women used nearly two more personal care products; non-Hispanic Black women, those with a college degree, and essential workers used 1-3 more household cleaning products. Women who were Hispanic or reported their race and ethnicity as Other were two times more likely to use antibacterial personal care products. Non-Hispanic Black, Hispanic, and women who reported their race and ethnicity as Other were 1.5 times more likely to increase antibacterial product use during the pandemic. Nearly all women agreed that environmental chemicals pose health risks and are impossible to avoid, while less than one quarter received advice regarding product use. Product use is a modifiable source of chemical exposures. Results from this study suggest that women may have increased their product use during the pandemic. Healthcare providers may use the current focus on health hygiene to promote discussion and assessment of environmental chemical exposures with patients.

Perfluoroalkyl substances (PFAS) in drinking water and risk for polycystic ovarian syndrome, uterine leiomyoma, and endometriosis: A Swedish cohort study

BACKGROUND

Perfluorinated substances (PFAS) are chemicals with endocrine disruptive properties that may interfere with the female reproductive system. However, few studies have explored the association between benign gynecological diseases and high PFAS exposure.

OBJECTIVES

The aim of this study was to investigate the possible associations between PFAS exposure and subsequent diagnosis of polycystic ovarian syndrome (PCOS), uterine leiomyoma (fibroids), and endometriosis in a cohort exposed to PFAS through drinking water.

MATERIAL AND METHODS

In 2013, high levels (with sum of PFAS above 10,000 ng/L), dominated by perfluorooctanesulfonic acid (PFOS) and perfluorohexane sulfonic acid (PFHxS), were found in the drinking water from one of the two waterworks in Ronneby, Sweden. The contamination came from firefighting foams used at a nearby airfield. Females of all ages (n = 29,106) who had ever resided in the municipality between 1985 and 2013 formed a cohort. Individual exposure was assessed based on municipality waterworks distribution data linked to annual residential address data; 27% of the females had ever lived at an address with PFAS-contaminated water. Gynecological health outcomes were retrieved from the Swedish National Patient Register. The Cox proportional hazards model was used to estimate the association between exposure and each diagnosis.

RESULTS

There were in all 161 cases of PCOS, 1,122 cases of uterine leiomyoma, and 373 cases of endometriosis. In women aged 20-50 years (n = 18,503), those with the highest estimated PFAS exposure had increased hazard ratios (HR) for PCOS (HR = 2.18; 95% confidence interval (CI) 1.43, 3.34) and uterine leiomyoma (HR = 1.28; 95% CI 0.95, 1.74). No increased HR for endometriosis was found (HR = 0.74; 95% CI 0.42, 1.29).

CONCLUSIONS

Exposure to high levels of PFAS in drinking water was associated with increased risk of PCOS and possibly uterine leiomyoma, but not endometriosis. The findings for PCOS are consistent with prior studies reporting positive associations between PCOS and PFAS exposure at background levels.

Endocrine-Disrupting Chemicals and Vitamin D Deficiency in the Pathogenesis of Uterine Fibroids

Uterine fibroids (UFs) are the most prevalent gynecologic neoplasm, affecting 70-80% of women over their lifespan. Although UFs are benign they can become life-threatening and require invasive surgeries such as myomectomy and hysterectomy. Notwithstanding the significant negative influence UFs have on female reproductive health, very little is known about early events that initiate tumor development. Several risk factors for UFs have been identified including vitamin D deficiency, inflammation, DNA repair deficiency, and environmental exposures to endocrine-disrupting chemicals (EDCs). EDCs have come under scrutiny recently due to their role in UF development. Epidemiologic studies have found an association between increased risk for early UF diagnosis and in utero EDC exposure. Environmental exposure to EDCs during uterine development increases UF incidence in a UF animal model. Notably, several studies demonstrated that abnormal myometrial stem cells (MMSCs) are the cell origin for UFs development. Our recent studies demonstrated that early-life EDC exposure reprogrammed the MMSCs toward a pro-fibroid landscape and altered the DNA repair and inflammation pathways. Notably, Vitamin D3 (VITD3) as a natural compound shrank the UF growth concomitantly with the reversion of several abnormal biological pathways and ameliorated the developmental exposure-induced DNA damage and pro-inflammation pathway in primed MMSCs. This review highlights and emphasizes the importance of multiple pathway interactions in the context of hypovitaminosis D at the MMSCs level and provides proof-of-concept information that can help develop a safe, long-term, durable, and non-surgical therapeutic option for UFs.

REPRODUCTIVE TOXICOLOGY: Endocrine disruption and reproductive disorders: impacts on sexually dimorphic neuroendocrine pathways

We are all living with hundreds of anthropogenic chemicals in our bodies every day, a situation that threatens the reproductive health of present and future generations. This review focuses on endocrine-disrupting compounds (EDCs), both naturally occurring and man-made, and summarizes how they interfere with the neuroendocrine system to adversely impact pregnancy outcomes, semen quality, age at puberty, and other aspects of human reproductive health. While obvious malformations of the genitals and other reproductive organs are a clear sign of adverse reproductive health outcomes and injury to brain sexual differentiation, the hypothalamic-pituitary-gonadal (HPG) axis can be much more difficult to discern, particularly in humans. It is well-established that, over the course of development, gonadal hormones shape the vertebrate brain such that sex-specific reproductive physiology and behaviors emerge. Decades of work in neuroendocrinology have elucidated many of the discrete and often very short developmental windows across pre- and postnatal development in which this occurs. This has allowed toxicologists to probe how EDC exposures in these critical windows can permanently alter the structure and function of the HPG axis. This review includes a discussion of key EDC principles including how latency between exposure and the emergence of consequential health effects can be long, along with a summary of the most common and less well-understood EDC modes of action. Extensive examples of how EDCs are impacting human reproductive health, and evidence that they have the potential for multi-generational physiological and behavioral effects are also provided.

Transcriptome aberration in mice uterus associated with steroid hormone response and inflammation induced by dioxybenzone and its metabolites

Benzophenone-type UV filters have been implicated in multiple adverse reproductive outcomes, yet the underlying processes and molecular targets on the female reproductive tract remain largely unknown. Herein, we investigated the effect of dioxybenzone, one of the widely used congeners, and its demethylated (M1) and hydroxylated (M2) metabolites on transcriptome profiles of ICR mice uterus and identified potential cellular targets in human endometrial stromal cells (HESCs) separated from normal endometrium tissues. Dioxybenzone, M1 and M2 (20 mg/kg bw/d) significantly induced transcriptome aberration with the induction of 683, 802, and 878 differentially expressed genes mainly involved in cancer, reproductive system disease and inflammatory disease. Compared to dioxybenzone, M1 and M2 exhibited a transcriptome profile more similar to estradiol in mice uterus, and subsequently promoted thicker endometrial columnar epithelial layer through upregulation of estrogen receptor target genes-Sprr2s. Dioxybenzone, M1 and M2 (0.1 or 1 μM) also exhibited estrogenic disrupting effect via increasing the mRNA expressions and production of the growth factors responsible for epithelial proliferation, including Fgfs and Igf-1 in HESCs. Additionally, the mRNA expressions of several inflammatory cytokines especially IL-1β in mice uterus and HESCs was significantly upregulated by dioxybenzone and its metabolites. Overall, we revealed that dioxybenzone and its metabolites triggered transcriptome perturbation dually associated with abnormal steroid hormone response and inflammation, both as key determinants to reproductive health risks.

The Role of Cell Proliferation and Extracellular Matrix Accumulation Induced by Food Additive Butylated Hydroxytoluene in Uterine Leiomyoma

Leiomyoma is the most common benign uterine tumor in reproductive-age women. Increasing numbers of studies are focusing on the effects of environmental exposure on the incidence and progression of tumors. One major step taken in the food industry is the addition of food preservatives to maintain freshness. Butylated hydroxytoluene (BHT) is a synthetic phenolic antioxidant, which is widely used as an additive to develop fat-soluble characteristics, as well as in cosmetics and rubber. Previous studies also highlighted that BHT may be related to increased fibrosis capacity and carcinogenic effects. In this study, we explored the effects of the commonly used food additive BHT on leiomyoma progression, and the related mechanism. The exposure of the ELT-3 leiomyoma cell line to BHT for 48 h increased the proliferative effect. Since leiomyoma progression is related to increases in extracellular matrix (ECM) accumulation and matrix metalloproteinase (MMP), BHT could effectively increase ECM-related protein expression, as well as MMP-2 and MMP-9 protein expression. This increase in ECM, in response to BHT, may be linked to the activation of the phosphoinositide 3-kinase (PI3K)/Akt and mitogen-activated protein kinase (MAPK) signaling pathway. Through PI3K inhibition, BHT’s effect on leiomyoma progression could be partially modulated. These results suggest the harmful effect of BHT exposure on leiomyoma progression may relate to PI3K modulation. However, an in vivo study is necessary to confirm these findings.

A cross-sectional study of the association between perfluorinated chemical exposure and cancers related to deregulation of estrogen receptors

BACKGROUND

Environmental exposures acting through different mechanisms have been linked with a number of cancers. Perfluoroalkyl chemicals (PFCs) are endocrine disrupting chemicals affecting estrogen homeostasis.

OBJECTIVES

We examined the association between PFCs and a group of estrogen related cancers and explored if increased non-occupational exposure was associated with increased odds of developing these cancers. We also explored which of these chemical exposures was more correlated with each cancer.

METHODS

Using data from the National Health and Nutrition Examination Survey (NHANES), we selected participants ≥ 20 years of age. Our outcome variable was presence or absence of breast, prostate, ovarian and uterine cancer (yes/no); our exposure variables were serum PFCs. Logistic regression models were used in investigating the association between PFCs and cancer types and between quartiles of PFCs exposure concentrations and presence or absence of cancer while adjusting for covariates. Discriminant analysis was used to assess the correlation between individual PFCs compounds and individual cancer types.

RESULTS

PFCs were associated with increased odds of ovarian cancer; PFOA: 1.02(1.01, 1.02), PFOS: 1.01 (1.012, 1.013), PFHS 1.031 (1.030, 1.033), PFDE: 1.29(1.27, 1.30) and increased odds of breast cancer; PFOA: 1.089(1.089, 1.09), PFOS: 1.011(1.011, 1.011), PFNA: 1.031(1.030, 1.033), PFHS: 1.02 (1.02, 1.02), PFDE: 1.19(1.18, 1.19). PFCs were not associated with increased odds of prostate or uterine cancers. Comparing the odds in quartile 4 to quartile 1 for ovarian cancer, PFOA: 1.77(1.75,1.79), PFOS: 2.25(2.22, 2.28), PFHS: 1.86(1.84, 1.88), PFDE: 2.11(2.09, 2.14). For breast cancer, PFOA: 2.30(2.28, 2.31), PFOS: 1.47(1.46, 1.48), PFNA: 1.04(1.03, 1.05), PFHS:7.07(6.97,7.17), PFDE: 1.38(1.37, 1.39). PFOA was more correlated with breast cancer (0.7) and PFHS was more correlated with ovarian cancer (0.9).

DISCUSSION

PFCs were associated with increased odds of ovarian and breast cancers with a positive dose-response relationship. PFOA was more correlated with breast cancer and PFHS more with ovarian cancer.

The influence of phenolic environmental estrogen on the transcriptome of uterine leiomyoma cells: A whole transcriptome profiling-based analysis

OBJECTIVE

The study aimed to recognize potential molecular targets and signal pathways whereby phenolic environmental estrogen promotes the proliferation of uterine leiomyoma cells.

METHODS

Primary cultured cell lines of uterine leiomyoma were treated with 0.1% DMSO, 10.0μmol/L Bisphenol A (BPA), and 32.0μmol/L Nonylphenol (NP) for 48 h before RNA-seq was performed. Those genes affected by BPA and NP were identified. Then, Gene Ontology (GO) enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, and Protein-protein Interaction (PPI) analysis were performed. Quantitative real-time polymerase chain reaction (q-PCR) and western blot were used to verify the differentially expressed gene and protein.

RESULTS

Compared to with the control group, 739 differentially expressed genes were identified in both the BPA group and the NP group. GO enrichment analysis showed that the most enriched GO terms were connective tissue development and G1/S transition of mitotic cell cycle, and extracellular matrix. The results of KEGG enrichment analysis showed that differentially expressed mRNA were enriched mainly in three primary pathways, including environmental information processing, human diseases, and cellular processes. The cell cycle, PI3K-Akt signaling pathway are significantly enriched. The q-PCR and western blot verified the cell cycle associated genes and proteins were upregulated in both BPA group and NP group. Both BPA and NP activated the PI3K-AKT signaling pathway.

CONCLUSION

Phenolic environmental estrogens may promote the proliferation and cell cycle progression of uterine leiomyoma cells through rapid non-genomic ER signaling, which leads to disordered cell cycle regulation and accelerates the transition of the cell cycle from G0/G1 phase to S phase. In addition, as an external stimulant, phenolic estrogen promotes the upregulation of inflammatory factors in uterine leiomyomas.

Endocrine Disruptors Acting on Estrogen and Androgen Pathways Cause Reproductive Disorders through Multiple Mechanisms: A Review

Increasing contamination of the environment by toxic compounds such as endocrine disrupting chemicals (EDCs) is one of the major causes of reproductive defects in both sexes. Estrogen/androgen pathways are of utmost importance in gonadal development, determination of secondary sex characteristics and gametogenesis. Most of the EDCs mediate their action through respective receptors and/or downstream signaling. The purpose of this review is to highlight the mechanism by which EDCs can trigger antagonistic or agonistic response, acting through estrogen/androgen receptors causing reproductive defects that lead to infertility. In vitro, in vivo and in silico studies focusing on the impact of EDCs on estrogen/androgen pathways and related proteins published in the last decade were considered for the review. PUBMED and PUBCHEM were used for literature search. EDCs can bind to estrogen receptors (ERα and ERβ) and androgen receptors or activate alternative receptors such as G protein-coupled receptors (GPCR), GPR30, estrogen-related receptor (ERRγ) to activate estrogen signaling via downstream kinases. Bisphenol A, dichlorodiphenyltrichloroethane, dichlorodiphenyldichloroethylene, polychlorinated biphenyls and phthalates are major toxicants that interfere with the normal estrogen/androgen pathways leading to infertility in both sexes through many ways, including DNA damage in spermatozoids, altered methylation pattern, histone modifications and miRNA expression.

Effects of Phthalate Esters on Human Myometrial and Fibroid Cells: Cell Culture and NOD-SCID Mouse Data

Evidence is growing that phthalate esters play an important role in the pathogenesis of estrogen-dependent gynecologic diseases, especially uterine fibroids. We aimed to investigate whether in vitro treatment with di-(2-ethylhexyl)-phthalate (DEHP) affects angiogenesis, proliferation, and apoptosis in uterine fibroids. To ascertain this, we evaluated vascular endothelial growth factor (VEGF) expression and AKT/ERT phosphorylation and compared the fibroid volume between nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice fed with and without DEHP. VEGF expression was measured using enzyme-linked immunosorbent assay, and AKT/ERK phosphorylation was analyzed by western blot analysis in human myometrial and fibroid cells. The volume of the fibroid tissues implanted to NOD/SCID mice was measured, and the expression of collagen type I protein, Ki-67, proliferating cell nuclear antigen, and B cell lymphoma 2 were analyzed using immunohistochemistry. We could see significant increases in VEGF expression and AKT phosphorylation in human myometrial and fibroid cells treated with DEHP. The volume of the fibroid tissues was significantly increased in NOD/SCID mice fed with DEHP, which was accompanied by increased expression of collagen type I and AKT phosphorylation. Taken together, these results suggest that exposure to phthalate esters may influence uterine fibroid pathogenesis by increasing VEGF and collagen expression and upregulating AKT phosphorylation.

Combined Exposure to Multiple Endocrine Disruptors and Uterine Leiomyomata and Endometriosis in US Women

BACKGROUND

Uterine leiomyomata (UL) and endometriosis (EM) are common gynecological diseases damaging the reproductive health of fertile women. Among all the potential factors, environmental endocrine-disrupting chemicals are insufficiently addressed considering the multiple pollutants and mixture exposure.

METHODS

Women aged 20 to 54 years old in the National Health and Nutrition Examination Survey (NHANES) 2001-2006, having a complete measurement of ten commonly exposed endocrine-disrupting chemicals (including urinary phthalate metabolites, equol, and whole blood heavy metals) and answered questions about UL and EM were included (N=1204). Multivariable logistic regression model, weighted quantile sum (WQS) regression, and Bayesian kernel machine regression (BKMR) models were implemented to analyze the combined effect of chemicals on the overall association with UL and EM.

RESULTS

In single chemical analysis, equol (OR: 1.90, 95% CI: 1.11, 3.27) and mercury (Hg) (OR: 1.91, 95% CI: 1.14, 3.25) were found positively associated with UL in tertile 3 vs. tertile 1. In WQS regression and BKMR models, the significant positive association between WQS index and UL (OR: 2.54, 95% CI: 1.52, 4.29) was identified and the positive relationship between equol and Hg exposure and UL were further verified. Besides, the mixture evaluation models (WQS and BKMR) also found MEHP negatively associated with UL. Although none of the single chemicals in tertile 3 were significantly associated with EM, the WQS index had a marginally positive association with EM (OR: 2.01, 95% CI: 0.98, 4.15), and a significant positive association was identified in subanalysis with participants restricted to premenopausal women (OR: 2.18, 95% CI: 1.03, 4.70). MIBP and MBzP weighted high in model of EM and MEHP weighted the lowest.

CONCLUSION

Comparing results from these three statistical models, the associations between equol, Hg, and MEHP exposure with UL as well as the associations of MIBP, MBzP, and MEHP exposure with EM warrant further research.

Hypothetical roadmap towards endometriosis: prenatal endocrine-disrupting chemical pollutant exposure, anogenital distance, gut-genital microbiota and subclinical infections

BACKGROUND

Endometriosis is a gynaecological hormone-dependent disorder that is defined by histological lesions generated by the growth of endometrial-like tissue out of the uterus cavity, most commonly engrafted within the peritoneal cavity, although these lesions can also be located in distant organs. Endometriosis affects ~10% of women of reproductive age, frequently producing severe and, sometimes, incapacitating symptoms, including chronic pelvic pain, dysmenorrhea and dyspareunia, among others. Furthermore, endometriosis causes infertility in ~30% of affected women. Despite intense research on the mechanisms involved in the initial development and later progression of endometriosis, many questions remain unanswered and its aetiology remains unknown. Recent studies have demonstrated the critical role played by the relationship between the microbiome and mucosal immunology in preventing sexually transmitted diseases (HIV), infertility and several gynaecologic diseases.

OBJECTIVE AND RATIONALE

In this review, we sought to respond to the main research question related to the aetiology of endometriosis. We provide a model pointing out several risk factors that could explain the development of endometriosis. The hypothesis arises from bringing together current findings from large distinct areas, linking high prenatal exposure to environmental endocrine-disrupting chemicals with a short anogenital distance, female genital tract contamination with the faecal microbiota and the active role of genital subclinical microbial infections in the development and clinical progression of endometriosis.

SEARCH METHODS

We performed a search of the scientific literature published until 2019 in the PubMed database. The search strategy included the following keywords in various combinations: endometriosis, anogenital distance, chemical pollutants, endocrine-disrupting chemicals, prenatal exposure to endocrine-disrupting chemicals, the microbiome of the female reproductive tract, microbiota and genital tract, bacterial vaginosis, endometritis, oestrogens and microbiota and microbiota-immune system interactions.

OUTCOMES

On searching the corresponding bibliography, we found frequent associations between environmental endocrine-disrupting chemicals and endometriosis risk. Likewise, recent evidence and hypotheses have suggested the active role of genital subclinical microbial infections in the development and clinical progression of endometriosis. Hence, we can envisage a direct relationship between higher prenatal exposure to oestrogens or estrogenic endocrine-disrupting compounds (phthalates, bisphenols, organochlorine pesticides and others) and a shorter anogenital distance, which could favour frequent postnatal episodes of faecal microbiota contamination of the vulva and vagina, producing cervicovaginal microbiota dysbiosis. This relationship would disrupt local antimicrobial defences, subverting the homeostasis state and inducing a subclinical inflammatory response that could evolve into a sustained immune dysregulation, closing the vicious cycle responsible for the development of endometriosis.

WIDER IMPLICATIONS

Determining the aetiology of endometriosis is a challenging issue. Posing a new hypothesis on this subject provides the initial tool necessary to design future experimental, clinical and epidemiological research that could allow for a better understanding of the origin of this disease. Furthermore, advances in the understanding of its aetiology would allow the identification of new therapeutics and preventive actions.

The role of endocrine-disrupting chemicals in uterine fibroid pathogenesis

PURPOSE OF REVIEW

Uterine leiomyoma (fibroids) is a gynecologic disorder impacting the majority of women in the United States. When symptomatic, these noncancerous tumors can cause severe morbidity including pelvic pain, menorrhagia, and infertility. Endocrine-disrupting chemicals (EDCs) may represent a modifiable risk factor. The aim of this review is to summarize recent human and experimental evidence on EDCs exposures and fibroids.

RECENT FINDINGS

Multiple EDCs are associated with fibroid outcomes and/or processes including phthalates, parabens, environmental phenols, alternate plasticizers, Diethylstilbestrol, organophosphate esters, and tributyltin. Epidemiologic studies suggest exposure to certain EDCs, such as di-(2-ethylhxyl)-phthalate (DEHP), are associated with increased fibroid risk and severity. Both human and experimental studies indicate that epigenetic processes may play an important role in linking EDCs to fibroid pathogenesis. In-vitro and in-vivo studies show that DEHP, bisphenol A, and diethylstilbestrol can impact biological pathways critical to fibroid pathogenesis.

SUMMARY

While research on EDCs and fibroids is still evolving, recent evidence suggests EDC exposures may contribute to fibroid risk and progression. Further research is needed to examine the impacts of EDC mixtures and to identify critical biological pathways and windows of exposure. These results could open the door to new prevention strategies for fibroids.

From bench to bedside: Biosensing strategies to evaluate endocrine disrupting compounds based on epigenetic events and their potential use in medicine

The relationship between endocrine system disorders and health risks due to chemical environmental compounds has become a growing concern in recent years. Involuntary exposure to endocrine disruptors (EDCs) is associated with the worldwide increase of diseases such as cancer, obesity, diabetes, and neurocortical disorders. EDCs are compounds that target the nuclear hormonereceptors (NHR) leading to epigenetic changes. Consequently, the use of biosensing strategies based on epigenetic events have a great potential to provide outstanding information about the exposition of EDCs and their evaluation in human health. This review addresses the novel trends in biosensing EDCs evaluation based on DNA methylation assays associated with different human diseases.

Exposure to organophosphate esters, phthalates, and alternative plasticizers in association with uterine fibroids

Exposure to endocrine disrupting chemicals is suggested to be responsible for the development or progression of uterine fibroids. However, little is known about risks related to emerging chemicals, such as organophosphate esters (OPEs) and alternative plasticizers (APs). A case-control study was conducted to investigate whether exposures to OPEs, APs, and phthalates, were associated with uterine fibroids in women of reproductive age. For this purpose, the cases (n = 32) and the matching controls (n = 79) were chosen based on the results of gynecologic ultrasonography among premenopausal adult women in Korea and measured for metabolites of several OPEs, APs, and major phthalates. Logistic regression models were employed to assess the associations between chemical exposure and disease status. Factor analysis was conducted for multiple chemical exposure assessments as a secondary analysis. Among OPE metabolites, diphenyl phosphate (DPHP), 2-ethylhexyl phenyl phosphate (EHPHP), and 1-hydroxy-2-propyl bis(1-chloro-2-propyl) phosphate (BCIPHIPP) were detected in >80% of the subjects. Among APs, metabolites of di-isononyl phthalate (DINP) and di(2-propylheptyl) phthalate (DPrHpP) were detected in >75% of the urine samples. The odds ratios (ORs) of uterine fibroids were significantly higher among the women with higher exposures to tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) and tris(2-butoxyethyl) phosphate (TBOEP), di(2-ethylhexyl) terephthalate (DEHTP), DPrHpP, and di-(iso-nonyl)-cyclohexane-1,2-dicarboxylate (DINCH). In addition, urinary concentrations of mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), a sum of five di(2-ethylhexyl) phthalate metabolites (∑5DEHP), and mono(4-methyl-7-hydroxyoctyl) phthalate (OH-MINP) were significantly higher in the cases. In factor analysis, a factor heavily loaded with DPrHpP and DEHP was significantly associated with uterine fibroids, supporting the observation from the single chemical regression model. We found for the first time that several metabolites of OPEs and APs are associated with increased risks of uterine fibroids among pre-menopausal women. Further epidemiological and mechanistic studies are warranted to validate the associations observed in the present study.

Role of DNA damage and repair mechanisms in uterine fibroid/leiomyomas: a review

There has been a significant annual increase in the number of cases of uterine leiomyomas or fibroids (UF) among women of all races and ages across the world. A fortune is usually spent by the healthcare sector for fibroid-related treatments and management. Molecular studies have established the higher mutational heterogeneity in UF as compared to normal myometrial cells. The contribution of DNA damage and defects in repair responses further increases the mutational burden on the cells. This in turn leads to genetic instability, associated with cancer risk and other adverse reproductive health outcomes. Such and many more growing bodies of literature have highlighted the genetic/molecular, biochemical and clinical aspects of UF; none the less there appear to be a lacuna bridging the bench to bed gap in addressing and preventing this disease. Presented here is an exhaustive review of not only the molecular mechanisms underlying the predisposition to the disease but also possible strategies to effectively diagnose, prevent, manage, and treat this disease.

UTERINE FIBROIDS IMPACT ON FERTILITY AND PREGNANCY OUTCOME

The clinical confirmation of the relationship between uterine leiomyoma and female infertility is of interest to scholars. The aim of our research was to study obstetric history and the level of sex hormones in women of reproductive age with leiomyoma. Materials and methods. The main group consisted of 90 women of reproductive age with uterine leiomyoma, the control group - 45 healthy women. Gynaecological and obstetric history, hormone content in peripheral blood and pelvic vessels (estradiol, progesterone) were analysed. Statistical processing of clinical material was performed using Microsoft Excel, Statistica 7.0, and Statistica 8.0 for Windows. Results. The frequency of infertility in the surveyed women with LM was 18.9 %. One in three patients in the main group (33.3 %) did not give birth, which was statistically different from the healthy women group. In this case, 25.6 % of women in the main group did not use any methods of contraception. It was found that 51.11 % of patients with LM had threatened miscarriage in their history, 37.5 % – complicated delivery. Pathological changes in the concentrations of estradiol and progesterone in the preferential blood and blood vessels of women with fibroids have been identified. We have found that the content of sex hormones in the local bloodstream has a reliable relationship with the location of the myomatous node. Conclusion. The obtained results may indicate that leiomyoma contributes to the reduction of fertility. This is evidenced by the fact that women with LM are more likely to have the risk of miscarriage, complicated delivery and delivery by caesarean section, including complicated one. The findings have made a significant contribution to the further development of effective strategies for the prevention and treatment of infertility in women with fibrotic uterine lesions.

Association of urinary metabolites of organophosphate and pyrethroid insecticides, and phenoxy herbicides with endometriosis

Endometriosis is a hormone-responsive gynecologic disease, signifying its connotations across a woman's life span. Previous studies suggested that endocrine disrupting chemicals were risk factors for endometriosis. Nevertheless, little is known on exposure to organophosphate, pyrethroid and phenoxy acid pesticides on endometriosis diagnosis. In this study, we determined the concentrations of 11 pesticides, metabolites of organophosphate and pyrethroid insecticides, and phenoxy herbicides, in urine collected from 619 reproductive-age women in Utah and California, using liquid chromatography-tandem mass spectrometry. The association of urinary concentrations of pesticides with an increase in the odds of endometriosis diagnosis was examined in 594 women who underwent laparoscopy/laparotomy (operative cohort: n = 471) or pelvic magnetic resonance imaging (population cohort: n = 123), during 2007-2009. 2-Isopropyl-4-methyl-6-hydroxypyrimidine (IMPY), malathion dicarboxylic acid (MDA), para-nitrophenol (PNP), 3,5,6-trichloro-2-pyridinol (TCPY), 3-phenoxybenzoic acid (3-PBA), and 2,4-dichlorophenoxyacetic acid (2,4-D) were detected in ≥95% of the urine samples analyzed. Urinary concentrations of IMPY, MDA, PNP, 3-PBA and 2,4-D tended to be higher in younger, non-Hispanic black, nulliparous and less affluent women. IMPY was the most dominant compound in urine followed by PNP and TCPY. When women in the 4th quartile of IMPY and the 2nd quartile of TCPY concentrations (μg/g creatinine) were compared with women in the 1st quartile, the odds ratios (ORs) for diagnosis of endometriosis increased significantly in unadjusted models (IMPY OR = 1.89, 95% confidence interval (Cl) = 1.12-3.20; TCPY OR = 1.65, 95% Cl = 1.02-2.69) for the operative (n = 471) and entire data set (n = 594), respectively. Our results suggest that exposure to elevated concentrations of diazinon (the parent compound of IMPY) and chlorpyrifos and chlorpyrifos-methyl (parent compounds of TCPY) may be associated with endometriosis.

Biomarkers in abnormal uterine bleeding†

Abnormal uterine bleeding (AUB) is an extremely common problem and represents a clinical area of unmet need. It has clinical implications and a high cost for the healthcare system. The PALM-COEIN acronym proposed by FIGO may be used as a foundation of care; it improves the understanding of the causes of AUB, and in doing so facilitates effective history taking, examination, investigations, and management. Heavy menstrual bleeding, a subset of AUB, is a subjective diagnosis and should be managed in the context of improving the woman's quality of life. Available evidence suggests that there is poor satisfaction with standard treatment options often resulting in women opting for major surgery such as hysterectomy. Such women would benefit from a tailored approach, both for diagnosis and treatment, highlighting the deficiency of biomarkers in this area. This article focuses on the causes of AUB as per the PALM-COEIN acronym, the researched biomarkers in this area, and the potential pathogenetic mechanisms. In the future, these approaches may improve our understanding of AUB, thereby enabling us to direct women to most suitable current treatments and tailor investigative and treatment strategies to ensure best outcomes, in keeping with the principles of personalized or precision medicine.

Perturbation of Nuclear Hormone Receptors by Endocrine Disrupting Chemicals: Mechanisms and Pathological Consequences of Exposure

Much of the early work on Nuclear Hormone Receptors (NHRs) focused on their essential roles as mediators of sex steroid hormone signaling in reproductive development and function, and thyroid hormone-dependent formation of the central nervous system. However, as NHRs display tissue-specific distributions and activities, it is not surprising that they are involved and vital in numerous aspects of human development and essential for homeostasis of all organ systems. Much attention has recently been focused on the role of NHRs in energy balance, metabolism, and lipid homeostasis. Dysregulation of NHR function has been implicated in numerous pathologies including cancers, metabolic obesity and syndrome, Type II diabetes mellitus, cardiovascular disease, hyperlipidemia, male and female infertility and other reproductive disorders. This review will discuss the dysregulation of NHR function by environmental endocrine disrupting chemicals (EDCs), and the associated pathological consequences of exposure in numerous tissues and organ systems, as revealed by experimental, clinical, and epidemiological studies.

Endocrine disruptor exposure during development increases incidence of uterine fibroids by altering DNA repair in myometrial stem cells

Despite the major negative impact uterine fibroids (UFs) have on female reproductive health, little is known about early events that initiate development of these tumors. Somatic fibroid-causing mutations in mediator complex subunit 12 (MED12), the most frequent genetic alterations in UFs (up to 85% of tumors), are implicated in transforming normal myometrial stem cells (MSCs) into tumor-forming cells, though the underlying mechanism(s) leading to these mutations remains unknown. It is well accepted that defective DNA repair increases the risk of acquiring tumor-driving mutations, though defects in DNA repair have not been explored in UF tumorigenesis. In the Eker rat UF model, a germline mutation in the Tsc2 tumor suppressor gene predisposes to UFs, which arise due to "second hits" in the normal allele of this gene. Risk for developing these tumors is significantly increased by early-life exposure to endocrine-disrupting chemicals (EDCs), suggesting increased UF penetrance is modulated by early drivers for these tumors. We analyzed DNA repair capacity using analyses of related gene and protein expression and DNA repair function in MSCs from adult rats exposed during uterine development to the model EDC diethylstilbestrol. Adult MSCs isolated from developmentally exposed rats demonstrated decreased DNA end-joining ability, higher levels of DNA damage, and impaired ability to repair DNA double-strand breaks relative to MSCs from age-matched, vehicle-exposed rats. These data suggest that early-life developmental EDC exposure alters these MSCs' ability to repair and reverse DNA damage, providing a driver for acquisition of mutations that may promote the development of these tumors in adult life.

NAMS 2018 Utian Translational Science Symposium, October 2018, San Diego, California New therapies for leiomyomas: when surgery may not be the best option

The North American Menopause Society (NAMS) held the 2018 Utian Translational Science Symposium on October 2, 2018, in San Diego, California, to discuss new therapeutic approaches to uterine leiomyomas when surgery is not the optimal choice.Uterine leiomyomas arise from a single clonal cell and are the most common gynecologic disorder affecting reproductive and perimenopausal women worldwide. The prevalence of this disorder is approximately 40% to 70% in white women and 60% to 80% in black women. Recent research suggests that both estrogen and progesterone modulate the growth of leiomyomas, with progesterone being a major stimulator of leiomyoma growth.Women with symptomatic uterine leiomyomas experience heavy uterine bleeding, bulk symptoms, miscarriages, and pregnancy complications. Surgical therapies such as myomectomy or hysterectomy are highly effective; however, medical therapy with progestin-predominant contraceptives or gonadotropin-releasing hormone (GnRH) agonists are in many ways inadequate to address the unmet need for better, noninvasive, and cost-effective treatments.Recent advances in medical treatment, such as selective progesterone receptor modulators, new oral GnRH analogs, and clinical trials that provide new therapeutic approaches, were presented by speakers at the symposium. Research on why there is a prevalence of leiomyomas in black women, the racial and genetic effects on leiomyoma growth, and potential molecular mechanisms also were discussed.

Burden of Uterine Fibroids: An African Perspective, A Call for Action and Opportunity for Intervention

Black women carry the burden of uterine fibroids, (AKA uterine leiomyomas), at a much higher rate than their racial counterparts. Thus, increasing awareness and discovering a solution to an endemic problem that plagues Sub-Saharan Africa is of critical importance, not only for the region itself, but also for the medical community globally. A collaborative, patient oriented, cost effective, and culturally sensitive approach must be at the forefront of this endeavor. While the exact pathogenesis of uterine fibroid development remains elusive, the racial disparity is well documented. Moreover, in the developed world, women are able to seek treatment through surgical and non-surgical means; however, sub-Saharan regions face their own challenges that, if not addressed, can ultimately extinguish the lives of many suffering women. Unfortunately, the literature is scarce on how to prevent fibroid development, which may be critical for women who do not have access to effective interventions. Recent research from our group and others has shown that vitamin D deficiency plays an important role in fibroid development and may be a preventable risk factor. Daily vitamin D supplementation is a low cost, effective intervention that could be implemented throughout the Sub-Saharan region. Similarly, education and increased awareness as to the nature and symptoms of uterine fibroids could improve the quality of life, remove negative social stigma, and reduce morbidity and mortality rates in women who seek medical care with advanced uterine fibroids.

Uterine polyps, adenomyosis, leiomyomas, and endometrial receptivity

Endometrial polyps, adenomyosis, and leiomyomas are commonly encountered abnormalities frequently found in both fertile women and those with infertility. The clinician is frequently challenged to determine which of these entities, when found, is likely to impair fertility, and which are "innocent bystanders" unrelated to the problem at hand. Although removing an endometrial polyp may be seen as a relatively benign and safe intervention, myomectomy, and in particular adenomyomectomy, can be substantive surgical procedures, associated with their own potential for disrupting fertility. One of the mechanisms thought to be involved when these entities are contributing to infertility is an adverse impact on endometrial receptivity. Indeed polyps, adenomyosis, and leiomyomas have all been associated with an increased likelihood of abnormal endometrial molecular expressions thought to impair implantation and early embryo development. This review is designed to examine the relationship of these common entities to endometrial receptivity and to identify evidence gaps that should be considered when strategizing research initiatives. It is apparent that we have the tools necessary to fill these gaps, but it will be necessary to approach the issue in a strategic and coordinated fashion. It is likely that we will have to recognize the limitations of imaging alone and look to the evidence-based addition of molecular analysis to provide the individualized phenotyping of disease necessary for patient-specific treatment decisions.

Perinatal outcome and long-term pediatric morbidity of pregnancies with a fibroid uterus

BACKGROUND

Uterine fibroids are a common morbidity in women and its prevalence is increasing with age. As maternal age rises, fibroids become more prevalent during pregnancy.

AIM

To assess perinatal outcome and long-term health of children to mothers with uterine fibroids during pregnancy.

STUDY DESIGN

A population-based cohort analysis assessing long-term hospitalizations of offspring, up to the age of 18 years, due to gastrointestinal, neurological, cardiovascular, endocrine, and respiratory morbidity, following pregnancies diagnosed with and without a fibroid uterus. Multivariable generalized estimating equation (GEE) analysis adjusted for maternal clusters and other possible confounders was performed. Kaplan-Meier survival curves and Cox survival regression models were used to compare cumulative morbidity incidence and control for confounders.

SUBJECTS

All singleton deliveries occurring between 1991 and 2014.

OUTCOME MEASURES

Perinatal outcome and long-term pediatric morbidity.

RESULTS

A total of 242,445 singleton deliveries were included; 0.5% of which were diagnosed with uterine fibroids (n = 1237). In the GEE multivariable analyses, advanced maternal age, hypertensive disorder and diabetes mellitus, fetal growth restriction, low birthweight (<2500 g), and small for gestational age newborns, were all independently associated with uterine fibroids during pregnancy. Hospitalizations up to the age of 18 years in the different health categories were comparable between the groups, using Cox regression models, controlled for clinically significant confounders in the long-term outcomes.

CONCLUSION

Maternal uterine fibroids appear to negatively impact perinatal outcome, mainly fetal growth. However, no independent major impact on future health of the offspring can be detected.

Epigenetic disruption of estrogen receptor alpha is induced by a glyphosate-based herbicide in the preimplantation uterus of rats

Previously, we have shown that perinatal exposure to a glyphosate-based herbicide (GBH) induces implantation failures in rats. Estrogen receptor alpha (ERα) is critical for successful implantation. ERα transcription is under the control of five promoters (E1, OT, O, ON, and OS), which yield different transcripts. Here, we studied whether perinatal exposure to a GBH alters uterine ERα gene expression and prompts epigenetic modifications in its regulatory regions during the preimplantation period. Pregnant rats (F0) were orally treated with 350 mg glyphosate/kg bw/day through food from gestational day (GD) 9 until weaning. F1 females were bred, and uterine samples were collected on GD5 (preimplantation period). ERα mRNA levels and its transcript variants were evaluated by RT-qPCR. Enzyme-specific restriction sites and predicted transcription factors were searched in silico in the ERα promoter regions to assess the methylation status using the methylation-sensitive restriction enzymes-PCR technique. Post-translational modifications of histones were studied by the chromatin immunoprecipitation assay. GBH upregulated the expression of total ERα mRNA by increasing the abundance of the ERα-O transcript variant. In addition, different epigenetic changes were detected in the O promoter. A decrease in DNA methylation was observed in one of the three sites evaluated in the O promoter. Moreover, histone H4 acetylation and histone H3 lysine 9 trimethylation (H3K9me3) were enriched in the O promoter in GBH-exposed rats, whereas H3K27me3 was decreased. All these alterations could account for the increase in ERα gene expression. Our findings show that perinatal exposure to a GBH causes long-term epigenetic disruption of the uterine ERα gene, which could be associated with the GBH-induced implantation failures.

Associations of urinary polycyclic aromatic hydrocarbons with age at natural menopause in U.S. women aged 35-65, NHANES 2003-2012

Polycyclic aromatic hydrocarbons (PAHs) mediated ovarian toxicity has been demonstrated in animal experiments. However, this issue has not been assessed in humans. Based on the National Health and Nutrition Examination Survey (NHANES) 2003-2012, data analysis was restricted to 1221 general U.S. women aged 35-65 years with complete data of interest. Levels of nine PAH metabolites in spot urine specimens were measured by isotope dilution gas chromatography/tandem mass spectrometry (GC-MS/MS). Self-reported information on the menopause status and age at menopause were obtained during interview. Cox proportional hazards regression was employed to assess the associations between PAH levels and natural menopause. Compared with women in the first quartile, subjects in the highest quartile of 1-Hydroxynapthalene [hazard ratio (HR) = 1.46, 95% confidence interval (CI) = 1.06 to 2.01], 2-Hydroxynapthalene (HR = 1.51, 95% CI = 1.12 to 2.05) and 3-Hydroxyfluorene (HR = 1.51, 95% CI = 1.06 to 2.16), or in the second quartile of 9-Hydroxyfluorene (HR = 1.53, 95% CI = 1.05 to 2.22), had elevated risks of earlier onset of natural menopause. Our findings suggested positive associations between urinary PAH levels and earlier age at natural menopause in the general U.S. women. Prospective studies are warranted to confirm the causality in the future.

Pathobiology of myomatosis uteri: the underlying knowledge to support our clinical practice

INTRODUCTION

Uterine myomatosis, a benign condition, is the most common indication for hysterectomies worldwide, affecting the reproductive goals and quality of health of women. However, gynecologists have been provided with interesting insights on its pathobiology, which are the basis for uterine-preserving therapies. The aim of this paper is to discuss the latest evidence on these mechanisms and its importance in the clinical practice.

METHOD

A comprehensive literature search was made in Pubmed, Medline, the Cochrane Library, Orbis plus and Google Scholar for articles related to the epidemiological, biological, and genetic bases.

RESULTS

There is extensive evidence that genetic, epigenetic, hormonal, environmental, proinflamatory, angiogenetic, and growing factors are involved in the biology of myomatosis. Such factors are capable of activating and promoting inhibitory signaling pathways leading to initiation, development, and regression of myomata through changes in myometrial cells and myomata fibers, such as cellular proliferation, differentiation, apoptosis, angiogenesis, and changes in the surrounding environment.

CONCLUSION

A good understanding of the pathobiologic mechanisms of myomatosis gives reasons to physicians to elect conservative or combined therapies, and allow affected women to receive an individualized management, according to age, reproduction desire, and clinical condition.

Literature Review on the Role of Uterine Fibroids in Endometrial Function

Uterine fibroids are benign uterine smooth muscle tumors that are present in up to 8 out of 10 women by the age of 50. Many of these women experience symptoms such as heavy and irregular menstrual bleeding, early pregnancy loss, and infertility. Traditionally believed to be inert masses, fibroids are now known to influence endometrial function at the molecular level. We present a comprehensive review of published studies on the effect of uterine fibroids on endometrial function. Our goal was to explore the current knowledge about how uterine fibroids interact with the endometrium and how these interactions influence clinical symptoms. Our review shows that submucosal fibroids produce a blunted decidualization response with decreased release of cytokines critical for implantation such as leukocyte inhibitory factor and cell adhesion molecules. Furthermore, fibroids alter the expression of genes relevant for implantation, such as bone morphogenetic protein receptor type II, glycodelin, among others. With regard to heavy menstrual bleeding, fibroids significantly alter the production of vasoconstrictors in the endometrium, leading to increased menstrual blood loss. Fibroids also increase the production of angiogenic factors such as basic fibroblast growth factor and reduce the production of coagulation factors resulting in heavy menses. Understanding the crosstalk between uterine fibroids and the endometrium will provide key insights into implantation and menstrual biology and drive the development of new and innovative therapeutic options for the management of symptoms in women with uterine fibroids.