Quantitative Differences in TGF-β Family Members Measured in Small Antral Follicle Fluids From Women With or Without PCO

The Role of Anti-Müllerian Hormone in Ovarian Function

Anti-Müllerian hormone (AMH) is a member of the transforming growth factor β (TGFβ) superfamily, whose actions are restricted to the endocrine-reproductive system. Initially known for its role in male sex differentiation, AMH plays a role in the ovary, acting as a gatekeeper in folliculogenesis by regulating the rate of recruitment and growth of follicles. In the ovary, AMH is predominantly expressed by granulosa cells of preantral and antral follicles (i.e., post primordial follicle recruitment and prior to follicle-stimulating hormone (FSH) selection). AMH signals through a BMP-like signaling pathway in a manner distinct from other TGFβ family members. In this review, the latest insights in AMH processing, signaling, its regulation of spatial and temporal expression pattern, and functioning in folliculogenesis are summarized. In addition, effects of AMH variants on ovarian function are reviewed.

Anti-Müllerian Hormone: A Molecular Key to Unlocking Polycystic Ovary Syndrome?

Anti-Müllerian hormone (AMH) is an important component within androgen receptor (AR)-regulated pathways governing the hyperandrogenic origin of polycystic ovary syndrome (PCOS). In women with PCOS, granulosa cell AMH overexpression in developing ovarian follicles contributes to elevated circulating AMH levels beginning at birth and continuing in adolescent daughters of PCOS women. A 6 to 7% incidence among PCOS women of gene variants coding for AMH or its receptor, AMHR2, suggests genetic contributions to AMH-related pathogenesis. Discrete gestational AMH administration to pregnant mice induces hypergonadotropic hyperandrogenic, PCOS-like female offspring with high circulating AMH levels that persist over three generations, suggesting epigenetic contributions to PCOS through developmental programming. Moreover, adult-onset, selective hyperactivation of hypothalamic neurons expressing gonadotropin-releasing hormone (GnRH) induces hypergonadotropic hyperandrogenism and PCOS-like traits in female mice. Both gestational and adult AMH inductions of PCOS-like traits are prevented by GnRH antagonist coadministration, implicating luteinizing hormone-dependent ovarian theca cell testosterone (T) action, mediated through the AR in AMH-induced pathogenesis. Interestingly, gestational or peripubertal exogenous T or dihydrotestosterone induction of PCOS-like traits in female mice, rats, sheep, and monkeys fails to elicit ovarian AMH hypersecretion; thus, AMH excess per se may lead to a distinct pathogenic contribution to hyperandrogenic PCOS origins.

A fresh start for IVM: capacitating the oocyte for development using pre-IVM

BACKGROUND

While oocyte IVM is practiced sporadically it has not achieved widespread clinical practice globally. However, recently there have been some seminal advances in our understanding of basic aspects of oocyte biology and ovulation from animal studies that have led to novel approaches to IVM. A significant recent advance in IVM technology is the use of biphasic IVM approaches. These involve the collection of immature oocytes from small antral follicles from minimally stimulated patients/animals (without hCG-priming) and an ∼24 h pre-culture of oocytes in an advanced culture system ('pre-IVM') prior to IVM, followed by routine IVF procedures. If safe and efficacious, this novel procedure may stand to make a significant impact on human ART practices.

OBJECTIVE AND RATIONALE

The objectives of this review are to examine the major scientific advances in ovarian biology with a unique focus on the development of pre-IVM methodologies, to provide an insight into biphasic IVM procedures, and to report on outcomes from animal and clinical human data, including safety data. The potential future impact of biphasic IVM on ART practice is discussed.

SEARCH METHODS

Peer review original and review articles were selected from PubMed and Web of Science searches for this narrative review. Searches were performed using the following keywords: oocyte IVM, pre-IVM, biphasic IVM, CAPA-IVM, hCG-triggered/primed IVM, natural cycle IVF/M, ex-vivo IVM, OTO-IVM, oocyte maturation, meiotic competence, oocyte developmental competence, oocyte capacitation, follicle size, cumulus cell (CC), granulosa cell, COC, gap-junction communication, trans-zonal process, cAMP and IVM, cGMP and IVM, CNP and IVM, EGF-like peptide and IVM, minimal stimulation ART, PCOS.

OUTCOMES

Minimizing gonadotrophin use means IVM oocytes will be collected from small antral (pre-dominant) follicles containing oocytes that are still developing. Standard IVM yields suboptimal clinical outcomes using such oocytes, whereas pre-IVM aims to continue the oocyte's development ex vivo, prior to IVM. Pre-IVM achieves this by eliciting profound cellular changes in the oocyte's CCs, which continue to meet the oocyte's developmental needs during the pre-IVM phase. The literature contains 25 years of animal research on various pre-IVM and biphasic IVM procedures, which serves as a large knowledge base for new approaches to human IVM. A pre-IVM procedure based on c-type natriuretic peptide (named 'capacitation-IVM' (CAPA-IVM)) has undergone pre-clinical human safety and efficacy trials and its adoption into clinical practice resulted in healthy live birth rates not different from conventional IVF.

WIDER IMPLICATIONS

Over many decades, improvements in clinical IVM have been gradual and incremental but there has likely been a turning of the tide in the past few years, with landmark discoveries in animal oocyte biology finally making their way into clinical practice leading to improved outcomes for patients. Demonstration of favorable clinical results with CAPA-IVM, as the first clinically tested biphasic IVM system, has led to renewed interest in IVM as an alternative, low-intervention, low-cost, safe, patient-friendly ART approach, and especially for patients with PCOS. The same new approach is being used as part of fertility preservation in patients with cancer and holds promise for social oocyte freezing.

Mechanisms of DHEA-induced AMH increase in the ovarian tissues of PCOS rat

The present study aimed to build a DHEA-induced polycystic ovary syndrome (PCOS) rat model to evaluate the potential mechanism of DHEA-induced AMH rise in these rat ovarian tissues. A total of 36 female 3-week-old rats were allocated into two groups at random. The control group received merely the same amount of sesame oil for 20 days while the experimental group received 0.2 mL of sesame oil Plus DHEA 6 mg/100 g daily. Both groups' vaginal opening times were noted, and vaginal smears were taken. By using RT-qPCR and Western blot, the mRNA and protein expression of AMH, GATA4, SF1, and SOX9 in the ovarian tissues of the two groups was investigated.The rats in the experimental group appeared to have obvious disorders of the estrus cycle, as evidenced by the ratio of estrus being significantly higher than that in the control group (P < 0.05); HE staining revealed that the ovarian volume, follicular vacuoles, and follicular lumen of the rats in the experimental group increased significantly.The ELISA results revealed that T and AMH in the experimental group were higher than those in the control group at day 15 and 20. AMH、GATA4 and SF1 mRNA and protein expression were higher in the experimental group than in the control group on day 15 and 20 (P < 0.05). On day 20, the experimental group outperformed the control group (P < 0.05). In the DHEA-induced PCOS rat model, androgen may have enhanced AMH expression via increasing the expression of genes associated to the AMH promoter binding site (GATA4, SF1, SOX9).

Application of specific ELISAs for BMP15 and GDF9 to cumulus cell extracts from infertile women

Bone morphogenetic protein 15 (BMP15) and growth differentiation factor 9 (GDF9) are oocyte-specific paracrine factors which regulate ovarian cumulus cell (CC) functions. This study aimed to investigate if BMP15 and GDF9 bound to CCs can be characterized, quantified, and show an association with IVF outcomes in infertile women. BMP15 and GDF9 ELISAs were validated and applied to discarded CC extracts. Pooled CCs from individual patients were collected from 120 (cohort 1; BMP15 only) and 81 infertility patients (cohort 2; BMP15 and GDF9) undergoing superovulation. BMP15 and GDF9 levels expressed per CC DNA were correlated with maternal age, clinical and embryology data. Total BMP15 and GDF9 were highly correlated with each other (r = 0.9, p < 0.001). The GDF9:BMP15 ratio was unrelated to oocyte number or age. BMP15/CC DNA and GDF9/CC DNA were unaffected by the type of superovulation and were not related to oocyte/embryo outcomes.

Serum GDF9 and BMP15 as potential markers of ovarian function in women with and without polycystic ovary syndrome

OBJECTIVE

Growth differentiation factor-9 (GDF9) and bone morphogenetic protein-15 (BMP15) are critical paracrine regulators of female fertility and are predominantly expressed by oocytes. However, it is unknown if serum concentrations reflect changes in ovarian function and/or reproductive endocrine disorders. This study aimed to determine if serum GDF9/BMP15 are associated with ovarian, pituitary, oestrogenic, androgenic and metabolic characteristics and the ovarian pathologies, polycystic ovarian morphology (PCOM) and polycystic ovary syndrome (PCOS).

DESIGN

Women aged 21-45 years (n = 381) were included from a cross-sectional study at the National University Hospital, Singapore.

PATIENTS

Participants were volunteers and patients with possible PCOS.

MEASUREMENTS

Anthropometric measurements, transvaginal ultrasound scans and serum sampling were performed and a questionnairecompleted. Serum GDF9 and BMP15 concentrations were matched with menstrual cycle length, ovarian protein and steroid hormone production, pituitary hormone production and metabolic assessments in women with PCOM or PCOS and those with neither (control).

RESULTS

Serum GDF9 and BMP15 were detectable in 40% and 41% of women, respectively and were positively correlated with each other (r = 0.08, p = 0.003). GDF9, but not BMP15, was positively correlated with ovarian volume (p = 0.02) and antral follicle count (AFC) (p = 0.004), but not with anti-Müllerian hormone (p = 0.05). However, serum GDF9 and BMP15 concentrations were not significantly different between control, PCOM and PCOS women, nor associated with androgenic or metabolic PCOS features. However, the relationship between GDF9 and AFC differed between control, PCOM and PCOS women (p = 0.02).

CONCLUSIONS

Serum GDF9 and BMP15 concentrations somewhat reflect ovarian but not androgenic or metabolic characteristics of PCOS, with increased GDF9 reflecting high AFC as seen in PCOM/PCOS.

Regulation of human oocyte maturation in vivo during the final maturation of follicles

STUDY QUESTION

Which substances and signal transduction pathways are potentially active downstream to the effect of FSH and LH in the regulation of human oocyte maturation in vivo?

SUMMARY ANSWER

The regulation of human oocyte maturation appears to be a multifactorial process in which several different signal transduction pathways are active.

WHAT IS KNOWN ALREADY

Many studies in animal species have provided insight into the mechanisms that govern the final maturation of oocytes. Currently, these studies have identified several different mechanisms downstream to the effects of FSH and LH. Some of the identified mechanisms include the regulation of cAMP/cGMP levels in oocytes involving C-type natriuretic peptide (CNP), effects of epidermal growth factor (EGF)-related peptides such as amphiregulin (AREG) and/or epiregulin (EREG), effect of TGF-β family members including growth differentiation factor 9 (GDF9) and morphogenetic protein 15 (BMP15), activins/inhibins, follicular fluid meiosis activating sterol (FF-MAS), the growth factor midkine (MDK), and several others. However, to what extent these pathways and mechanisms are active in humans in vivo is unknown.

STUDY DESIGN, SIZE, DURATION

This prospective cohort study included 50 women undergoing fertility treatment in a standard antagonist protocol at a university hospital affiliated fertility clinic in 2016-2018.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We evaluated the substances and signalling pathways potentially affecting human oocyte maturation in follicular fluid (FF) and granulosa cells (GCs) collected at five time points during the final maturation of follicles. Using ELISA measurement and proteomic profiling of FF and whole genome gene expression in GC, the following substances and their signal transduction pathways were collectively evaluated: CNP, the EGF family, inhibin-A, inhibin-B, activins, FF-MAS, MDK, GDF9, and BMP15.

MAIN RESULTS AND THE ROLE OF CHANCE

All the evaluated substances and signal transduction pathways are potentially active in the regulation of human oocyte maturation in vivo except for GDF9/BMP15 signalling. In particular, AREG, inhibins, and MDK were significantly upregulated during the first 12-17 h after initiating the final maturation of follicles and were measured at significantly higher concentrations than previously reported. Additionally, the genes regulating FF-MAS synthesis and metabolism were significantly controlled in favour of accumulation during the first 12-17 h. In contrast, concentrations of CNP were low and did not change during the process of final maturation of follicles, and concentrations of GDF9 and BMP15 were much lower than reported in small antral follicles, suggesting a less pronounced influence from these substances.

LARGE SCALE DATA

None.

LIMITATIONS, REASONS FOR CAUTION

Although GC and cumulus cells have many similar features, it is a limitation of the current study that information for the corresponding cumulus cells is not available. However, we seldom recovered a cumulus-oocyte complex during the follicle aspiration from 0 to 32 h.

WIDER IMPLICATIONS OF THE FINDINGS

Delineating the mechanisms governing the regulation of human oocyte maturation in vivo advances the possibility of developing a platform for IVM that, as for most other mammalian species, results in healthy offspring with good efficacy. Mimicking the intrafollicular conditions during oocyte maturation in vivo in small culture droplets during IVM may enhance oocyte nuclear and cytoplasmic maturation. The primary outlook for such a method is, in the context of fertility preservation, to augment the chances of achieving biological children after a cancer treatment by subjecting oocytes from small antral follicles to IVM. Provided that aspiration of oocytes from small antral follicles in vivo can be developed with good efficacy, IVM may be applied to infertile patients on a larger scale and can provide a cheap alternative to conventional IVF treatment with ovarian stimulation. Successful IVM has the potential to change current established techniques for infertility treatment.

STUDY FUNDING/COMPETING INTEREST(S)

This research was supported by the University Hospital of Copenhagen, Rigshospitalet, the Independent Research Fund Denmark (grant number 0134-00448), and the Interregional EU-sponsored ReproUnion network. There are no conflicts of interest to be declared.

A cross-sectional study comparing the inflammatory profile of menstrual effluent vs. peripheral blood

Background and Aims

Cytokine profiles of peripheral blood and other bodily fluids provide diagnostic indicators for assessing inflammatory processes. Menstrual effluent may provide a noninvasive source of biological material for monitoring cytokine levels in blood and in endometrial tissues. This pilot study investigated the potential of measuring cytokines in menstrual effluent, and compared the cytokine profiles of menstrual versus peripheral blood.

Methods

Seven healthy donors (aged ≥18 and ≤45 years) collected menstrual effluent on day 2 of menses. Matched peripheral blood samples were collected by venous blood draw on the same day. Levels of 62 cytokines were measured in all samples by 62-plex Luminex assay.

Results

Peripheral blood and menstrual effluent cytokine profiles were tenuously correlated (r ² = 0.26, p < 0.0001), with higher levels detected in menstrual effluent for 48/62 cytokines. Thirty five cytokines were significantly elevated in menstrual effluent compared to peripheral blood samples (IL-8, CCL2, CCL4, LIF, IL-1RA, IL-6, IL-1β, HGF, CCL3, FGF-2, TNF-α, VEGF-A, IL-1α, CXCL1, IL-9, IL-10, EGF, CXCL5, CSF3, EOTAXIN, TGF-α, TRAIL, CXCL10, VEGF-D, IL-12P40, CXCL9, IL-18 RESISTIN, IL-22, IL-21, CSF1, IFN-γ, IL-17A, CXCL12, IL-12p70). Two cytokines (LEPTIN, CSF2) were expressed at significantly lower levels in menstrual effluent compared to peripheral blood. Linear regression of individual cytokines found low predictive power (linear regression p > 0.05) for 53/62 cytokines in menstrual effluent versus peripheral blood. Levels of TGF-β (r ² = 0.87, p = 0.002) and CCL7 (r ² = 0.63, p = 0.033) were significantly positively correlated between matched menstrual and peripheral blood samples.

Conclusion

In this group of study participants, the cytokine profile of menstrual effluent was quantitatively distinct from peripheral blood, and also characterized by higher levels of inflammatory signaling. This pattern of comparative menstrual blood cytokine profiles points to a need for further studies to evaluate the relationship between peripheral and menstrual blood cytokines in broader populations including both healthy and diseased states.

Concentrations of oocyte secreted GDF9 and BMP15 decrease with MII transition during human IVM

BACKGROUND

The suggested effects of the oocyte secreted GDF9 and BMP15 growth factors on oocyte maturation are currently based on recombinant proteins, and little is known about native GDF9 and BMP15 in humans.

METHODS

Human immature cumulus-oocyte complexes (COCs) obtained in connection with ovarian tissue cryopreservation (OTC) underwent in vitro maturation (IVM). Oocyte-produced GDF9 and BMP15 were detected in COCs using immunofluorescence, and in fresh GV oocytes and in GV and MII oocytes after IVM by western blot. Concentrations of GDF9, BMP15 homodimers, and GDF9/BMP15 heterodimer in spent media after IVM were measured by ELISA. The relative expression of seven genes from the GDF9 and BMP15 signaling pathways (BMPR2, ALK5, ALK6, SMAD1, SMAD2, SMAD3, and SMAD5) was evaluated in fresh cumulus cells (before IVM) and in cumulus cells from GV and MII oocytes after IVM by RT-qPCR.

RESULTS

We detected native pro-mature GDF9 and BMP15 in human oocytes with molecular weights (Mw) of 47 kDa and 43 kDa, respectively. Concentrations of GDF9 and BMP15 in spent media after IVM were detected in 99% and 64% of the samples, respectively. The GDF9/BMP15 heterodimer was detected in 76% of the samples. Overall, the concentration of GDF9 was approximately 10-times higher than BMP15. The concentrations of both GDF9 and BMP15 were significantly lower in spent medium from MII oocytes than in media from oocytes that remained at the GV stage. Concentrations of the GDF9/BMP15 heterodimer did not differ between GV and MII oocytes. Furthermore, BMPR2, SMAD3, and SMAD5 were significantly upregulated in cumulus cells from MII oocytes, indicating that both GDF9 and BMP15 signaling were active during oocyte meiotic resumption in vitro.

CONCLUSION

These data suggest that the driving mechanisms for oocyte nuclear maturation may involve both GDF9 and BMP15 homodimers, while the role of the GDF9/BMP15 heterodimer is questionable.

Comparison of 3 Different AMH Assays With AMH Levels and Follicle Count in Women With Polycystic Ovary Syndrome

CONTEXT

Anti-Müllerian hormone (AMH) levels strongly correlate with the number of antral follicles (total follicle count, TFC) in the ovary. In women with polycystic ovary syndrome (PCOS), this is reflected by significantly increased serum AMH levels. Different assays have been developed to measure AMH. However, little is known about the interassay correlation in women with increased AMH levels.

OBJECTIVE

To investigate the correlation of AMH values between different AMH assays and with TFC in PCOS patients.

METHODS

AMH levels were measured in 1660 PCOS patients, using 3 different AMH assays: Gen II (Beckman Coulter); picoAMH (Ansh Labs); and Elecsys (Roche). Passing Bablok regression was used to compare assay methods. Spearman's correlation was used to correlate AMH levels and TFC.

RESULTS

Strong interassay correlations were present over the total range of AMH levels (0.81-0.94). Stratification in subgroups, revealed an AMH level-dependent interassay correlation with strong interassay correlations in the low (<2.80 ng/mL) and high (>7.04 ng/mL) subgroups (0.62-0.86). However, the correlation in the mid-AMH subgroup (2.80-7.04 ng/mL) was only moderate (0.28-0.56). A strong correlation was present between the total range of AMH levels and TFC (0.57-0.62). However, in all 3 AMH subgroups the correlation became moderate at best, independently of assay method (0.11-0.45).

CONCLUSION

In conclusion, both the interassay correlation and the correlation between AMH level and follicle count depend on the range of serum AMH levels. This once more emphasizes the need of a standardization of AMH measurement for an accurate interpretation of AMH in clinical practice.

Intrafollicular Concentrations of the Oocyte-secreted Factors GDF9 and BMP15 Vary Inversely in Polycystic Ovaries

CONTEXT

The oocyte-secreted factors growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) play essential roles in follicle development and oocyte maturation, and aberrant regulation might contribute to the pathogenesis of polycystic ovary syndrome.

OBJECTIVE

Are there measurable differences in concentrations of GDF9, BMP15, and the GDF9/BMP15 heterodimer in small antral follicle fluids from women with and without polycystic ovaries (PCO)?

DESIGN AND SETTING

Follicle fluids (n = 356) were collected from 4- to 11-mm follicles in unstimulated ovaries of 87 women undergoing ovarian tissue cryopreservation for fertility preservation.

PATIENTS

Twenty-seven women with PCO were identified and 60 women without PCO-like characteristics (non-PCO women) were matched according to age and follicle size.

MAIN OUTCOME MEASURES

Intrafollicular concentrations of GDF9, BMP15, GDF9/BMP15 heterodimer, anti-Mullerian hormone (AMH), inhibin-A and -B, total inhibin, activin-B and -AB, and follistatin were measured using enzyme-linked immunosorbent assays.

RESULTS

The detectability of GDF9, BMP15, and the GDF9/BMP15 heterodimer were 100%, 94.4%, and 91.5%, respectively, and concentrations were significantly negatively correlated with increasing follicle size (P < 0.0001). GDF9 was significantly higher in women with PCO (PCO: 4230 ± 189 pg/mL [mean ± SEM], n = 188; non-PCO: 3498 ± 199 pg/mL, n = 168; P < 0.03), whereas BMP15 was lower in women with PCO (PCO: 431 ± 40 pg/mL, n = 125; non-PCO: 573 ± 55 pg/mL, n = 109; P = 0.10), leading to a significantly higher GDF9:BMP15 ratio in women with PCO (P < 0.01). Significant positive associations between BMP15 and AMH, activins, and inhibins in non-PCO women switched to negative associations in women with PCO.

CONCLUSIONS

Intrafollicular concentrations of GDF9 and BMP15 varied inversely in women with PCO reflecting an aberrant endocrine environment. An increased GDF9:BMP15 ratio may be a new biomarker for PCO.

Proteomic Alterations in Follicular Fluid of Human Small Antral Follicles Collected from Polycystic Ovaries—A Pilot Study

Polycystic ovaries (PCO) contain antral follicles that arrest growing around 3–11 mm in diameter, perturbing the dominant follicle’s selection and the subsequent ovulatory process. Proteomic alterations of PCO follicular fluid (FF) (i.e., microenvironment in which the oocyte develops until ovulation) have been studied from large follicles in connection with oocyte pickup during ovarian stimulation. The present study aimed to detect proteomic alterations in FF from unstimulated human small antral follicles (hSAF) obtained from PCO. After performing deep-sequencing label-free proteomics on 10 PCO and 10 non-PCO FF samples from unstimulated hSAF (4.6–9.8 mm), 1436 proteins were identified, of which 115 were dysregulated in PCO FF samples. Pathways and processes related to the immune system, inflammation, and oxidative stress appeared to be upregulated in PCO, while extracellular matrix receptors interactions, the collagens-containing extracellular matrix, and the regulation of signaling were downregulated. The secreted proteins SFRP1, THBS4, and C1QC significantly decreased their expression in PCO FF, and this downregulation was suggested to affect future oocyte competence. In conclusion, our study revealed, for the first time, evidence of proteomic alterations occurring in the FF of PCO hSAF that may be related to the dysfunction of follicular growth and subsequent oocyte competence.

The role of follicular anti-Mullerian hormone in women undergoing IVF/ICSI with regard to size, oocyte presence, sociodemographic parameters, treatment variables, and other hormones and vitamins

AIMS

The aim of this study was to evaluate the relationship between follicular anti-Mullerian hormone (fAMH) regarding follicle size, the presence of an oocyte, sociodemographic parameters, and other hormones and vitamins in follicular fluid.

MATERIALS AND METHODS

This prospective exploratory cohort study included 376 follicles from 61 women undergoing IVF/ICSI cycles. The size of each follicle was measured individually, and they were divided into a large and a small group according to their size. The presence of oocytes was detected on the day of oocyte retrieval. Sociodemographic factors were documented during the course of preliminary testing. Then, other parameters of patients' serum and follicular fluid were measured.

RESULTS

Small follicles contained a significantly higher concentration of fAMH than large ones did. We showed that the presence of an oocyte in a follicle is associated with a significantly higher fAMH level than in those without one (p < .001). There exists a significant but weak correlation between fAMH and the sociodemographic parameter of patients' age (r = -0.11, p < .001). We did not find a correlation with the patients' BMI (r = 0.03, p < .006). We also investigated the connections between fAMH and other parameters, such as vitamin D (r = -0.13, p < .001), LH (r = 0.35, p < .001)), and progesterone (r = -0.21, p < .001) in follicular fluid.

CONCLUSIONS

This knowledge can be useful for the future development of reproductive medicine. Our results can provide an important building block for this matter.

Maternal Perinatal Exposure to Dibutyl Phthalate Promotes Ovarian Dysfunction in Adult Female Offspring via Downregulation of TGF-β2 and TGF-β3

Maternal exposure to dibutyl phthalate (DBP) may result in ovarian dysfunction in female offspring. However, the underlying mechanisms remain elusive. Pregnant Sprague-Dawley rats were intraperitoneally injected with different doses of DBP, estradiol, and corn oil from gestational day 7 until the end of lactation. The reproductive characteristics, mRNA, and protein expression of ovaries for the adult female offspring were compared. KGN cells were cultured in vitro with DBP, estrogen receptor antagonist, or ALK-5 inhibitor. Genes, proteins, estradiol, and progesterone expressed by KGN, cell proliferation, and apoptosis were measured respectively. Maternal perinatal exposure to DBP induced prolonged estrous period, increased secondary follicles, significant decreased mRNA, and protein levels of TGF-β2, TGF-β3, and TGF-βRII in ovaries of the adult female offspring, but none difference for serum levels of sex hormones, ovarian TGF-β1, and estrogen receptor. The mRNA levels of LHR, FSHR, and CYP19a in ovaries were also decreased. DBP might decrease the mRNA of TGF-β2, TGF-β3, and TGF-βR II of KGN. DBP can inhibit the mRNA of CYP19 at 24 h, which might be blocked by the estrogen receptor antagonist, whose effects were attenuated at 48 h. DBP combined with FSH might time-dependently regulate the gene expression of TGF-βR II, inhibitory at 24 h, but stimulative at 48 h, which could be blocked by the ALK5 inhibitor. However, the protein expressed by KGN was not influenced by DBP. DBP stimulated the proliferation of KGN at 24 h, which could be blocked by estrogen receptor antagonist, but attenuated at 48 h. The progesterone in culture medium secreted by KGN was decreased by DBP at 24 h. Maternal perinatal exposure to DBP induced decreased gene expression of TGF-β signaling and functional proteins in ovaries of the adult female offspring. Molecular cross-talk between estrogen receptor and TGF-β signaling pathway may play role in the mechanism of granulosa dysfunction induced by DBP.

OUP accepted manuscript

STUDY QUESTION

Do polymorphisms in the anti-Müllerian hormone (AMH) promoter have an effect on AMH levels in patients with polycystic ovary syndrome (PCOS)?

SUMMARY ANSWER

We have identified a novel AMH promoter polymorphism rs10406324 that is associated with lower serum AMH levels and is suggested to play a role in the mechanism of regulation of AMH gene expression in women.

WHAT IS KNOWN ALREADY

Follicle number is positively correlated with serum AMH levels, reflected by elevated AMH levels in women with PCOS. In addition, it is suggested that AMH production per follicle is higher in women with PCOS than in normo-ovulatory women, implying an altered regulation of AMH in PCOS.

STUDY DESIGN, SIZE, DURATION

A discovery cohort of 655 PCOS women of Northern European ancestry and both an internal and external validation PCOS cohort (n = 458 and n = 321, respectively) were included in this study. Summary-level data of an AMH genome-wide association study meta-analysis including 7049 normo-ovulatory women was included as a control cohort. A genetic approach was taken through association analysis and in silico analysis of the associated variants in the AMH promoter. In vitro analysis was performed to investigate the functional mechanisms.

PARTICIPANTS/MATERIALS, SETTING, METHODS

All common two-allelic single-nucleotide polymorphisms (SNPs) in the region Chr19:2 245 353–2 250 827 bp (Build 37) were selected for the analysis. Linear regression analyses were performed to determine the association between SNPs in the AMH promoter region and serum AMH levels. For the in silico analysis, the webtools ‘HaploReg’ v4.1 for ENCODE prediction weight matrices and ‘atSNP’ were used. In vitro analysis was performed using KK1 cells, a mouse granulosa cell line and COV434 cells, a human granulosa tumor cell line. Cells were transfected with the reference or the variant human AMH promoter reporter construct together with several transcription factors (TFs). Dual-Glo^® Luciferase Assay was performed to measure the luciferase activity.

MAIN RESULTS AND THE ROLE OF CHANCE

Polymorphism rs10406324 was significantly associated with serum AMH levels in all three PCOS cohorts. Carriers of the minor allele G had significantly lower log-transformed serum AMH levels compared to non-carriers (P = 8.58 × 10⁻⁸, P = 1.35 × 10⁻³ and P = 1.24 × 10⁻³, respectively). This result was validated in a subsequent meta-analysis (P = 3.24 × 10⁻¹²). Interestingly, rs10406324 was not associated with follicle count, nor with other clinical traits. Also, in normo-ovulatory women, the minor allele of this variant was associated with lower serum AMH levels (P = 1.04 × 10⁻⁵). These findings suggest that polymorphism rs10406324 plays a role in the regulation of AMH expression, irrespective of clinical background. In silico analysis suggested a decreased binding affinity of the TFs steroidogenenic factor 1, estrogen-related receptor alpha and glucocorticoid receptor to the minor allele G variant, however in vitro analysis did not show a difference in promoter activity between the A and G allele.

LIMITATIONS, REASONS FOR CAUTION

Functional analyses were performed in a mouse and a human granulosa cell line using an AMH promoter reporter construct. This may have limited assessment of the impact of the polymorphism on higher order chromatin structures. Human granulosa cells generated from induced pluripotent stem cells, combined with gene editing, may provide a method to elucidate the exact mechanism behind the decrease in serum AMH levels in carriers of the −210 G allele. We acknowledge that the lack of follicle number in the external validation and the control cohort is a limitation of the paper. Although we observed that the association between rs10406324 and AMH levels was independent of follicle number in our discovery and internal validation PCOS cohorts, we cannot fully rule out that the observed effects on serum AMH levels are, in part, caused by differences in follicle number.

WIDER IMPLICATIONS OF THE FINDINGS

These results suggest that variations in serum AMH levels are not only caused by differences in follicle number but also by genetic factors. Therefore, the genetic context should be taken into consideration when assessing serum AMH levels in women. This may have clinical consequences when serum AMH levels are used as a marker for the polycystic ovarian morphology phenotype.

STUDY FUNDING/COMPETING INTEREST(S)

No external funding was used. J.S.E.L. has received consultancy fees from the following companies: Ferring, Roche Diagnostics and Ansh Labs and has received travel reimbursement from Ferring. J.A.V. has received royalties from AMH assays, paid to the institute/lab with no personal financial gain. The other authors declare no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Anti-Müllerian Hormone in Pathogenesis, Diagnostic and Treatment of PCOS

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder among reproductive-aged women. It is characterized by chronic anovulation, hyperandrogenism, and the presence of polycystic ovary in ultrasound examination. PCOS is specified by an increased number of follicles at all growing stages, mainly seen in the preantral and small antral follicles and an increased serum level of Anti-Müllerian Hormone (AMH). Because of the strong correlation between circulating AMH levels and antral follicle count on ultrasound, Anti-Müllerian Hormone has been proposed as an alternative marker of ovulatory dysfunction in PCOS. However, the results from the current literature are not homogeneous, and the specific threshold of AMH in PCOS and PCOM is, therefore, very challenging. This review aims to update the current knowledge about AMH, the pathophysiology of AMH in the pathogenesis of PCOS, and the role of Anti-Müllerian Hormone in the treatment of this syndrome.

Control of ovarian follicle development by TGFβ family signaling

The reproductive lifespan of female mammals is limited and ultimately depends on the production of a sufficient number of high quality oocytes from a pool of non-growing primordial follicles that are set aside during embryonic and perinatal development. Recent studies show multiple signaling pathways are responsible for maintaining primordial follicle arrest and regulation of activation. Identification of these pathways and their regulatory mechanisms is essential for developing novel treatments for female infertility, improving existing in vitro fertilization techniques, and more recently, restoring the function of cryopreserved ovarian tissue. This review focuses on recent developments in transforming growth factor beta (TGFβ) family signaling in ovarian follicle development and its potential application to therapeutic design. Mouse models have been an essential tool for discovering genes critical for fertility, and recent advancements in human organ culture have additionally allowed for the translation of murine discoveries into human research and clinical settings.

Association of bioavailable inhibin B and oocyte yield in controlled ovarian stimulation

Objective

To determine if the biologically active or bioavailable inhibin B (bio-inhB) correlated with the oocyte yield in controlled ovarian stimulation (COS).

Design

Cross-sectional study.

Setting

Academic center.

Patient(s)

Women undergoing oocyte cryopreservation.

Intervention(s)

None.

Main Outcome Measure(s)

Serum of women were sampled to measure bio-inhB at three points: baseline (“start”); middle (“mid”); and end of COS. A validated, highly specific enzyme-linked immunosorbent assay (Ansh Labs, Webster, TX) measured bio-inhB. The Spearman tests analyzed correlations between bio-inhB and other ovarian reserve markers, including age, follicle-stimulating hormone (FSH), antral follicle count (AFC), and antimüllerian hormone (AMH), and correlations between these markers and oocyte yield.

Result(s)

A total of 144 women were included. Bioavailable inhibin B at the mid and end of COS, plus its delta, were strongly correlated with other ovarian reserve markers. As the bio-inhB concentration increased, the AFC and AMH levels also increased, whereas the FSH concentration and age decreased. Bioavailable inhibin B values, except at the start of COS, were more strongly correlated with oocyte yield than the FSH concentration (r = 0.72–0.82 vs. r = −0.44) and correlated similarly to the AFC and AMH concentration (r = 0.79 and 0.81, respectively). These correlations strengthened in those with diminished ovarian reserve, specifically age ≥35 years or AMH concentration <2 ng/mL (r = 0.71–0.86 vs. r = 0.49–0.67).

Conclusion(s)

Predicting COS outcome is imperfect. When using a highly specific enzyme-linked immunosorbent assay, bio-inhB correlated with the oocyte yield similar to or more strongly than traditionally used ovarian reserve markers. These correlations strengthened in cases of diminished ovarian reserve. Bioavailable inhibin B provides physicians with an additional clinical tool for estimating COS outcome.

Exploratory analysis of serum concentrations of oocyte biomarkers growth differentiation factor 9 and bone morphogenetic protein 15 in ovulatory women across the menstrual cycle

OBJECTIVE

To characterize and evaluate the variation in serum concentrations of oocyte-secreted growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) throughout the menstrual cycle in women from young to advanced reproductive ages.

DESIGN

Cross-sectional, observational, and exploratory study.

SETTING

Multicenter university-based clinical practices and laboratories.

PATIENT(S)

Serum was collected every 1-3 days throughout the menstrual cycle from 3 cohorts of healthy, ovulatory women: menses to late luteal phase (21-29 years of age; n = 16; University of Otago) and across one interovulatory interval (18-35 years of age; n = 10; and 45-50 years of age; n = 15; University of Saskatchewan).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

To detect the changes in serum GDF9 and BMP15 across the cycle, mean concentration and variance were statistically modeled using a generalized additive model of location, shape and scale (GAMLSS). Follicle-stimulating hormone, luteinizing hormone, estradiol, progesterone, and anti-Müllerian hormone were also assessed.

RESULT(S)

GDF9 and BMP15 were detectable in 54% and 73% of women and varied 236-fold and 52-fold between women, respectively. Across the menstrual cycle, there were minimal changes in GDF9 or BMP15 within a woman for all cohorts, with no significant differences detected in the modeled mean concentrations. However, modeled variances were highest in the luteal phases of all women for BMP15 immediately after ovulation, regardless of age.

CONCLUSION(S)

Serial changes in GDF9 or BMP15 concentrations across the cycle were not statistically detected and are likewise similar across the reproductive lifespan. Further research is required to fully elucidate the utility of these oocyte biomarkers at diagnosing fertility potential and/or disease.

Abnormalities of early folliculogenesis and serum anti-Müllerian hormone in chinese patients with polycystic ovary syndrome

Purpose

To investigate abnormalities of early folliculogenesis and Anti-Müllerian hormone (AMH) concentrations in polycystic ovary syndrome (PCOS) patients, and to analyze the association between AMH and early-stage follicle densities (FD).

Methods

A total of 175 patients underwent ovarian tissue cryopreservation in the first official cryobank in China, of which 16 patients aged 30–40 years old were diagnosed with endometrial cancer (all without initial chemo/radiotherapy), including 5 patients with concurrent PCOS and the other 11 patients without. We obtained standard cortical biopsies to measure FD using calcein staining. Blood samples were collected before cryopreservation to evaluate AMH concentrations.

Results

PCOS showed nearly three times the primordial and primary FD than NPCOS (P = 0.027), as well as more secondary preantral follicles (P = 0.002). A significantly higher proportion of secondary preantral follicles and a lower proportion of primordial and primary follicles were observed in PCOS (P = 0.01). Furthermore, the AMH concentration in PCOS was four times higher than that in NPCOS (P = 0.003), which is significantly correlated with primordial and primary follicle densities (r = 0.855, P < 0.001) and secondary preantral follicle densities (r = 0.732, P = 0.007).

Conclusions

We found significant disorders of early folliculogenesis in PCOS, which showed close correlation with increased AMH concentrations. To our knowledge, abnormalities of early-stage follicles have been shown for the first time in ovarian tissue of Chinese PCOS women. We suppose that the elevated AMH level is associated with abnormalities of early folliculogenesis within the complex PCOS pathogenesis, which may explain why AMH has the potential to be used as a biomarker for the diagnosis of PCOS. Our findings provide more implications for understanding the mechanism of PCOS, and new directions for further studies.

PAPP-A2 and Inhibin A as Novel Predictors for Pregnancy Complications in Women With Suspected or Confirmed Preeclampsia

Background

We aimed to evaluate the value of inhibin A and PAPP‐A2 (pregnancy‐associated plasma protein‐A2) as novel biomarkers in the prediction of preeclampsia‐related complications and how they compare with angiogenic biomarkers.

Methods and Results

Making use of a secondary analysis of a prospective, multicenter, observational study, intended to evaluate the usefulness of sFlt‐1 (soluble Fms‐like tyrosine kinase‐1)/PlGF (placental growth factor) ratio, we measured inhibin A and PAPP‐A2 levels in 524 women with suspected/confirmed preeclampsia. Women had a median gestational age of 35 weeks (range, 20–41 weeks) while preeclampsia occurred in 170 (32%) women. Levels of inhibin A and PAPP‐A2 were significantly increased in women with preeclampsia and in maternal perfusate of preeclamptic placentas. Inhibin A and PAPP‐A2 (C‐index = 0.73 and 0.75) significantly improved the prediction of maternal complications when added on top of the traditional criteria; gestational age, parity, proteinuria, and diastolic blood pressure (C‐index = 0.60). PAPP‐A2 was able to improve the C‐index from 0.75 to 0.77 when added on top of the sFlt‐1/PlGF ratio for the prediction of maternal complications. To discriminate fetal/neonatal complications on top of traditional criteria, inhibin A and PAPP‐A2 showed additive value (C‐index = 0.79 to 0.80 and 0.82, respectively) but their discriminative ability remained inferior to that of sFlt‐1/PlGF ratio or PlGF. Interestingly, the PAPP‐A2/PlGF ratio alone showed remarkable value to predict pregnancy complications, being superior to sFlt‐1/PlGF ratio in the case of maternal complications.

Conclusions

Inhibin A and PAPP‐A2 show significant potential to predict preeclampsia‐related pregnancy complications and might prove beneficial on top of the angiogenic markers.

Rate and Extent of Recovery from Reproductive and Cardiac Dysfunction Due to Androgen Abuse in Men

CONTEXT

Androgen abuse impairs male reproductive and cardiac function, but the rate, extent, and determinants of recovery are not understood.

OBJECTIVE

To investigate recovery of male reproductive and cardiac function after ceasing androgen intake in current and past androgen abusers compared with healthy non-users.

METHODS

Cross-sectional, observational study recruited via social media 41 current and 31 past users (≥3 months since last use, median 300 days since last use) with 21 healthy, eugonadal non-users. Each provided a history, examination, and serum and semen sample and underwent testicular ultrasound, body composition analysis, and cardiac function evaluation.

RESULTS

Current abusers had suppressed reproductive function and impaired cardiac systolic function and lipoprotein parameters compared with non- or past users. Past users did not differ from non-users, suggesting full recovery of suppressed reproductive and cardiac functions after ceasing androgen abuse, other than residual reduced testicular volume. Mean time to recovery was faster for reproductive hormones (anti-Mullerian hormone [AMH], 7.3 months; luteinizing hormone [LH], 10.7 months) than for sperm variables (output, 14.1 months) whereas spermatogenesis (serum follicle-stimulating hormone [FSH], inhibin B, inhibin) took longer. The duration of androgen abuse was the only other variable associated with slower recovery of sperm output (but not hormones).

CONCLUSION

Suppressed testicular and cardiac function due to androgen abuse is effectively fully reversible (apart from testis volume and serum sex hormone binding globulin) with recovery taking between 6 to 18 months after ceasing androgen intake with possible cumulative effects on spermatogenesis. Suppressed serum AMH, LH, and FSH represent convenient, useful, and underutilized markers of recovery from androgen abuse.