Ovarian follicular fluid levels of phthalates and benzophenones in relation to fertility outcomes

Single-cell RNA-seq reveals that granulosa cells are a target of phthalate toxicity in the ovary

Phthalates are known endocrine-disrupting chemicals and ovarian toxicants that are used widely in consumer products. Phthalates have been shown to exert ovarian toxicity on multiple endpoints, altering transcription of genes responsible for normal ovarian function. However, the molecular mechanisms by which phthalates act on the ovary are not well understood. In this study, we hypothesized that phthalates specifically target granulosa cells within the ovarian follicle. To test our hypothesis, we cultured whole mouse antral follicles for 96 h in the presence of vehicle or 10 µg/ml of a phthalate metabolite mixture. At the end of the culture period, follicles were dissociated into single-cell suspensions and subjected to single-cell RNA-sequencing. We used markers from published studies to identify cell-type clusters, the largest of which were granulosa and theca/stroma cells. We further identified subpopulations of granulosa, theca, and stromal cells and analyzed differentially expressed genes between the phthalate treatment and control. Granulosa cells, specifically mural granulosa cells, had the most differentially expressed genes. Pathway analysis of differentially expressed genes from the overall granulosa cell cluster revealed disruption of cell cycle and mitosis, whereas pathway analysis of the mural granulosa cell subcluster identified terms related to translation, ribosome, and endoplasmic reticulum. Our findings suggest that phthalates have both broad impacts on cell types and specific impacts on cellular subtypes, emphasizing the complexity of phthalate toxicity and highlighting how bulk sequencing can mask effects on vulnerable cell types.

Phthalates are detected in the follicular fluid of adolescents and oocyte donors with associated changes in the cumulus cell transcriptome

OBJECTIVE

To investigate the follicular fluid (FF) phthalate levels in adolescents undergoing fertility preservation compared with oocyte donors and explore its association with ovarian reserve and cumulus cell (CC) gene expression.

DESIGN

Retrospective study and molecular analysis of CCs and FF.

SUBJECTS

Adolescents (n = 20, 16.7 ± 0.6 years) undergoing fertility preservation and oocyte donors (n = 24, 26.2 ± 0.4 years).

EXPOSURE

Not applicable.

MAIN OUTCOME MEASURES

Patient demographics, ovarian stimulation, and oocyte retrieval outcomes were analyzed for each group. The FF levels of 9 phthalate metabolites were assessed individually and as molar sums representative of common compounds (all phthalates, ƩPhthalates; di(2-ethylhexyl) phthalate (DEHP)-associated phthalate metabolites, ƩDEHP), exposure sources (plastics, ƩPlastic; personal care products, ƩPCP), and modes of action (antiandrogenic, ƩAA) and compared between the 2 groups. The transcriptome of CC associated with mature oocytes was compared between adolescents and oocyte donors using bulk ribonucleic acid sequencing.

RESULTS

The FF ƩPlastic and ƩPCP levels were significantly higher in adolescents than in oocyte donors. The FF ƩDEHP, ƩPlastic, ƩPCP, ƩAA, and ƩPhthalates levels were positively associated with antral follicle count in oocyte donors when adjusted for age, body mass index, and race/ethnicity. Ribonucleic acid sequencing analysis revealed 248 differentially expressed genes in CCs of adolescents within the top quartile (n = 4) of the FF ƩPhthalates levels compared with those of the adolescents within the bottom half (n = 9). Genes enriched in pathways involved in cell motility and development were significantly down-regulated.

CONCLUSIONS

Adolescents undergoing fertility preservation cycles demonstrate higher levels of phthalate metabolites in their FF than oocyte donors. Higher phthalate levels are associated with alterations in cumulus cells transcriptome in adolescents. The phthalate metabolite levels in FF are associated with higher antral follicle count levels in oocyte donors.

Distribution of Environmental Phenols into Follicular Fluid and Urine of Women Attending Infertility Clinic

Infertility and environmental pollution are two globally prevalent and related issues. To explore women's reproductive health, the composition of follicular fluid (FF) has been studied and it was found that changes to its composition, including the presence of exogenous chemicals, can adversely affect the fertilization process. Two groups of women (idiopathic infertility and controls) who were patients at a fertility clinic were recruited for this study. Samples of urine and FF were gathered from each participant to determine the concentration of 14 common phenols (four parabens, six bisphenols, two benzophenones, and two naphthols). Associations between phenol concentrations (free and total) in both matrices were described using Spearman's correlation coefficient and were compared between two groups by the Mann-Whitney U test. Eight phenols were quantified in more than 50% of the urine samples, while only three parabens were quantified in hydrolyzed FF samples, and only methylparaben was quantified in non-hydrolyzed FF samples. Conjugates were the predominant form in FF samples. However, a significant correlation of 0.533 (p < 0.0001) was observed between free and total methylparaben concentrations in FF. Differences in concentrations between cases and controls in both matrices were not statistically significant, except for benzophenone-3 in urine, with a higher median observed in the control group (p = 0.04). The total paraben concentrations in urine and FF samples were rather weakly correlated (r = 0.232-0.473), implying that urine concentrations may not be appropriate for predicting their concentration in FF.

In Vitro Toxicity of a DEHP and Cadmium Mixture on Sheep Cumulus-Oocyte Complexes

Di-(2-ethylhexyl) phthalate (DEHP) and Cadmium (Cd) affect female reproduction. To date, toxicological research has focused on the effects of individual contaminants, whereas living beings are exposed to mixtures. This study analyzed the effects of a DEHP/Cd mixture on nuclear and cytoplasmic maturation of sheep cumulus-oocyte complexes (COCs) compared with single compounds. COCs recovered from slaughterhouses-derived sheep ovaries were in vitro exposed to 0.5 μM DEHP, 0.1 μM Cd, or DEHP/Cd mixture at the same concentrations during 24 h of in vitro maturation (IVM). After IVM, oocyte nuclear chromatin configuration was evaluated, and bioenergetic/oxidative parameters were assessed on expanded cumulus cells (CCs) and matured oocytes (chi-square test and one-way ANOVA; p < 0.05). Under examined conditions, oocyte nuclear maturation was never impaired. However, COC bioenergetics was affected with stronger effects for the mixture than single compounds. Indeed, the percentages of matured oocytes with healthy mitochondrial distribution patterns were reduced (p < 0.001 and p < 0.05 for mixture and single compounds, respectively). Oocyte mitochondrial membrane potential, intracellular ROS levels, and mitochondria/ROS co-localization were reduced, with the same significance level, in all contaminated conditions. CCs displayed increased ROS levels only upon mixture exposure (p < 0.001). In conclusion, in vitro exposure to the DEHP/Cd mixture affected COC quality in the sheep to a greater extent than separate compounds.

Prenatal exposure to low doses of benzophenone-3 elicits disruption of cortical vasculature in fetuses through perturbations in Wnt/β-catenin signaling correlating with depression-like behavior in offspring mice

Benzophenone-3 (BP-3), commonly used in personal care products, is routinely detected in environmental and human matrices. Evidence delineates a correlation between gestational BP-3 exposure and emotional and social disorders in children and adolescents. However, sensitive target cells and the mode of action underlying the early responses to environmentally relevant level of BP-3 exposure remain unclear. In this study, 0.3 and 3 mg/kg of BP-3 were administered to pregnant mice. Compared with the control group, the cortical blood vessel development process manifested the highest susceptibility to BP-3 exposure using transcriptomic sequencing at embryonic day 14 (E14). Notably, the diminution in vascular density and tight junction proteins presence was observed in the fetal cortex at E14, concomitant with the suppressed transcriptional activity of genes essential to angiogenesis and barrier formation. Strikingly, the investigation revealed that BP-3 exposure impeded vascular sprouting in aortic ring explants and neuroendothelial migration, implicating the Wnt/β-catenin signaling pathway. Moreover, BP-3 exposure compromised perivascular neural stem cell differentiation. Cortical vascular injury correlated with the exhibition of depression-like behavior in four-week postnatal progeny. These insights underscore the cerebrovasculature as an early sensitive target for low doses of BP-3 exposure, fostering the development of biomarkers and the establishment of the adverse outcome pathway framework for BP-3 hazard evaluation.

Characterization of Chemical Exposome in A Paired Human Preconception Pilot Study

Parental preconception exposure to synthetic chemicals may have critical influences on fertility and reproduction. Here, we present a robust LC-MS/MS method covering up to 95 diverse xenobiotics in human urine, serum, seminal and follicular fluids to support exposome-wide assessment in reproductive health outcomes. Extraction recoveries of validated analytes ranged from 62% to 137% and limits of quantification from 0.01 to 6.0 ng/mL in all biofluids. We applied the validated method to a preconception cohort of Australian couples (n = 30) receiving fertility treatment. In total, 36 and 38 xenobiotics were detected across the paired biofluids of males and females, respectively, including PFAS, parabens, organic UV-filters, plastic additives, antimicrobials, and other industrial chemicals. Results showed 39% of analytes in males and 37% in females were equally detected in paired serum, urine, and reproductive fluids. The first detection of the sunscreen ingredient avobenzone and the industrial chemical 4-nitrophenol in follicular and seminal fluids suggests they can cross both blood-follicle/testis barriers, indicating potential risks for fertility. Further, the blood-follicle transfer of perfluorobutanoic acid, PFOA, PFHxS, PFOS, and oxybenzone corroborate that serum concentrations can be reliable proxies for assessing exposure within the ovarian microenvironment. In conclusion, we observed significant preconception exposure to multiple endocrine disruptors in couples and identified potential xenobiotics relevant to male and female fertility impairments.

Which is the current knowledge on man-made endocrine- disrupting chemicals in follicular fluid? An overview of effects on ovarian function and reproductive health

The increase in female reproductive disorders, such as polycystic ovary syndrome, endometriosis, and diminished ovarian reserve that lead to subfertility and infertility, has encouraged researchers to search and discover their underlying causes and risk factors. One of the crucial factors that may influence the increasing number of reproductive issues is environmental pollution, particularly exposure to man-made endocrine-disrupting chemicals (EDCs). EDCs can interfere with the ovarian microenvironment, impacting not only granulosa cell function but also other surrounding ovarian cells and follicular fluid (FF), which all play essential roles for oocyte development, maturation, and overall reproductive function. FF surrounds developing oocytes within an ovarian follicle and represents a dynamic milieu. EDCs are usually found in biological fluids, and FF is therefore of interest in this respect. This narrative review examines the current knowledge on specific classes of EDCs, including industrial chemicals, pesticides, and plasticizers, and their known effects on hormonal signaling pathways, gene expression, mitochondrial function, oxidative stress induction, and inflammation in FF. We describe the impact of EDCs on the development of reproductive disorders, oocyte quality, menstrual cycle regulation, and their effect on assisted reproductive technique outcomes. The potential transgenerational effects of EDCs on offspring through animal and first-human studies has been considered also. While significant progress has been made, the current understanding of EDCs' effects on ovarian function, particularly in humans, remains limited, underscoring the need for further research to clarify actions and effects of EDCs in the ovary.

Phthalates are detected in the follicular fluid of adolescents and oocyte donors with associated changes in the cumulus cell transcriptome

Purpose

To investigate follicular fluid (FF) phthalate levels in adolescents undergoing fertility preservation compared to oocyte donors and explore its association with ovarian reserve and cumulus cell gene expression.

Methods

20 Adolescents (16.7 ± 0.6 years old) and 24 oocyte donors (26.2 ± 0.4 years old) undergoing fertility preservation were included in the study. Patient demographics, ovarian stimulation and oocyte retrieval outcomes were analyzed for each group. FF levels of 9 phthalate metabolites were assessed individually and as molar sums representative of common compounds (all phthalates: ΣPhthalates; DEHP: ΣDEHP), exposure sources (plastics: ΣPlastic; personal care products: ΣPCP), and modes of action (anti-androgenic: ΣAA) and compared between the two groups.

Results

Follicular fluid ΣPlastic and ΣPCP levels were significantly higher in adolescents compared to oocyte donors (p<0.05). Follicular fluid ΣDEHP, ΣPlastic, ΣPCP, ΣAA, and ΣPhthalates levels were positively associated with antral follicle count (AFC) (p<0.05) in oocyte donors when adjusted for age, BMI, and race/ethnicity. RNA-seq analysis revealed 248 differentially expressed genes (DEGs) in cumulus cells of adolescents within the top quartile (n=4) of FF ΣPhthalates levels compared to the adolescents within the bottom half (n=9). Genes enriched in pathways involved in cell motility and development were significantly downregulated.

Conclusion

Adolescents undergoing fertility preservation cycles demonstrate higher levels of phthalate metabolites in their follicular fluid compared to oocyte donors. Phthalate metabolite levels in FF are associated with higher AFC levels in oocyte donors. Higher phthalate levels in FF are associated with alterations in the cumulus cells transcriptome in adolescents.