Anti-Müllerian hormone promotes pre-antral follicle growth, but inhibits antral follicle maturation and dominant follicle selection in primates

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.

Identification and functional analysis of ovarian lncRNAs during different egg laying periods in Taihe Black-Bone Chickens

Introduction: Long non-coding RNA (lncRNA) refers to a category of non-coding RNA molecules exceeding 200 nucleotides in length, which exerts a regulatory role in the context of ovarian development. There is a paucity of research examining the involvement of lncRNA in the regulation of ovary development in Taihe Black-Bone Chickens. In order to further investigate the egg laying regulation mechanisms of Taihe Black-Bone Chickens at different periods, transcriptome analysis was conducted on the ovarian tissues at different laying periods. Methods: This study randomly selected ovarian tissues from 12 chickens for RNA-seq. Four chickens were selected for each period, including the early laying period (102 days, Pre), the peak laying period (203 days, Peak), and the late laying period (394 days, Late). Based on our previous study of mRNA expression profiles in the same ovarian tissue, we identified three differentially expressed lncRNAs (DE lncRNAs) at different periods and searched for their cis- and trans-target genes to draw an lncRNA-mRNA network. Results and discussion: In three groups of ovarian tissues, we identified 136 DE lncRNAs, with 8 showing specific expression during the early laying period, 10 showing specific expression during the peak laying period, and 4 showing specific expression during the late laying period. The lncRNA-mRNA network revealed 16 pairs of lncRNA-target genes associated with 7 DE lncRNAs, and these 14 target genes were involved in the regulation of reproductive traits. Furthermore, these reproductive-related target genes were primarily associated with signaling pathways related to follicle and ovary development in Taihe Black-Bone Chickens, including cytokine-cytokine receptor interaction, TGF-beta signaling pathway, tyrosine metabolism, ECM-receptor interaction, focal adhesion, neuroactive ligand-receptor interaction, and cell adhesion molecules (CAMs). This study offers valuable insights for a comprehensive understanding of the influence of lncRNAs on poultry reproductive traits.

Characterization of the molecular mechanisms that govern anti-Müllerian hormone synthesis and activity

The roles of anti-Müllerian hormone (AMH) continue to expand, from its discovery as a critical factor in sex determination, through its identification as a regulator of ovarian folliculogenesis, its use in fertility clinics as a measure of ovarian reserve, and its emerging role in hypothalamic-pituitary function. In light of these actions, AMH is considered an attractive therapeutic target to address diverse reproductive needs, including fertility preservation. Here, we set out to characterize the molecular mechanisms that govern AMH synthesis and activity. First, we enhanced the processing of the AMH precursor to >90% by introducing more efficient proprotein convertase cleavage sites (RKKR or ISSRKKRSVSS [SCUT]). Importantly, enhanced processing corresponded with a dramatic increase in secreted AMH activity. Next, based on species differences across the AMH type II receptor-binding interface, we generated a series of human AMH variants and assessed bioactivity. AMHSCUT potency (EC50 4 ng/mL) was increased 5- or 10-fold by incorporating Gln484 Met/Leu535 Thr (EC50 0.8 ng/mL) or Gln484 Met/Gly533 Ser (EC50 0.4 ng/mL) mutations, respectively. Furthermore, the Gln484 Met/Leu535 Thr double mutant displayed enhanced efficacy, relative to AMHSCUT . Finally, we identified residues within the wrist pre-helix of AMH (Trp494 , Gln496 , Ser497 , and Asp498 ) that likely mediate type I receptor binding. Mutagenesis of these residues generated gain- (Trp494 Phe or Gln496 Leu) or loss- (Ser497 Ala) of function AMH variants. Surprisingly, combining activating type I and type II receptor mutations only led to modest additive increases in AMH potency/efficacy. Our study is the first to characterize AMH residues involved in type I receptor binding and suggests a step-wise receptor-complex assembly mechanism, in which enhancement in the affinity of the ligand for either receptor can increase AMH activity beyond the natural level.

New insights into the role of LH in early ovarian follicular growth: a possible tool to optimize follicular recruitment

Evidence shows that LH participates in enhancing transition from the early stage to the antral stage of folliculogenesis. It has been demonstrated that functional LH receptors are expressed, albeit at a very low level and even in smaller follicles, during the phase that was traditionally considered to be gonadotrophin independent, suggesting a role for LH in accelerating the rate of progression of non-growing and primary follicles to the preantral/antral stage. Hypogonadotropic hypogonadism, together with other clinical conditions of pituitary suppression, has been associated with reduced functional ovarian reserve. The reduction in LH serum concentration is associated with a low concentration of anti-Müllerian hormone. This is the case in hypothalamic amenorrhoea, pregnancy, long-term GnRH-analogue therapy and hormonal contraception. The effect seems to be reversible, such that after pregnancy and after discontinuation of drugs, the functional ovarian reserve returns to the baseline level. Evidence suggests that women with similar primordial follicle reserves could present with different numbers of antral follicles, and that gonadotrophins may play a fundamental role in permitting a normal rate of progression of follicles through non-cyclic folliculogenesis. The precise role of gonadotrophins in early folliculogenesis, as well as their use to modify the functional ovarian reserve, must be investigated.

Potential factors result in diminished ovarian reserve: a comprehensive review

The ovarian reserve is defined as the quantity of oocytes stored in the ovary or the number of oocytes that can be recruited. Ovarian reserve can be affected by many factors, including hormones, metabolites, initial ovarian reserve, environmental problems, diseases, and medications, among others. With the trend of postponing of pregnancy in modern society, diminished ovarian reserve (DOR) has become one of the most common challenges in current clinical reproductive medicine. Attributed to its unclear mechanism and complex clinical features, it is difficult for physicians to administer targeted treatment. This review focuses on the factors associated with ovarian reserve and discusses the potential influences and pathogenic factors that may explain the possible mechanisms of DOR, which can be improved or built upon by subsequent researchers to verify, replicate, and establish further study findings, as well as for scientists to find new treatments.

AMH and other markers of ovarian function in patients with Turner syndrome - a single center experience of transition from pediatric to gynecological follow up

Turner syndrome (TS) is a chromosomal disorder that affects about 1 in 2500 female births and is characterized by the partial or complete absence of the second X chromosome. Depending on karyotype, TS is associated with primary ovarian insufficiency (POI). Approximately 50% of girls with a mosaic 45, X/46, XX karyotype may enter puberty spontaneously, but only 5-10% of women with TS achieve pregnancy without egg donation. In this review, we will evaluate the clinical use of markers of ovarian function in TS patients. Based on longitudinal studies of serum concentrations of reproductive hormones as well as ovarian morphology in healthy females and patients with TS, we will evaluate how they can be applied in a clinical setting. This is important when counseling patients and their families about future ovarian function essential for pubertal development and fertility. Furthermore, we will report on 20 years of experience of transition from pediatric to gynecological and adult endocrinological care in our center at Rigshospitalet, Copenhagen, Denmark.

Anti-Müllerian hormone-mediated preantral follicle atresia is a key determinant of antral follicle count in mice

STUDY QUESTION

Does anti-Müllerian hormone (AMH) induce preantral follicle atresia in mice?

SUMMARY ANSWER

The present findings suggest that AMH-mediated follicle atresia only occurs in early follicles before they become sensitive to FSH.

WHAT IS KNOWN ALREADY

Most prior studies have investigated the ability of AMH to inhibit primordial follicle activation. Our previous study showed that AMH-overexpressing mice had fewer preantral follicles than expected after accounting for primordial follicle inhibition but the reason for this was not determined.

STUDY DESIGN, SIZE, DURATION

Cross-sectional-control versus transgenic/knockout mouse studies were carried out.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Studies were conducted on female wild-type (Amh+/+), AMH-knockout (Amh-/-) and AMH overexpressing (Thy1.2-AMHTg/0) mice on a C57Bl/6J background (age: 42-120 days). The follicle counts were conducted for primordial, transitioning, primary, secondary and antral follicles in Amh-/- and Amh+/+ mice. After confirming that follicle development speeds were identical (proliferating cell nuclear antigen immunohistochemistry), the ratio of follicles surviving beyond each stage of folliculogenesis was determined in both genotypes. Evidence for increased rates of preantral follicle atresia was assessed by active caspase-3 immunohistochemistry in wild-type and Thy1.2-AMHTg/0 mice.

MAIN RESULTS AND THE ROLE OF CHANCE

Amh -/- mice at 100-120 days of age had lower primordial follicle counts but higher primordial follicle activation rates compared to Amh+/+ mice. These counteracting effects led to equivalent numbers of primordial follicles transitioning to the primary stage in Amh+/+ and Amh-/- mice. Despite this, Amh+/+ mice had fewer primary, secondary, small antral and medium antral follicles than Amh-/- mice indicating differing rates of developing follicle atresia between genotypes. Cleaved caspase-3 immunohistochemistry in Thy1.2-AMHTg/0 ovaries revealed high rates of granulosa cell and oocyte apoptosis in late primary/early secondary follicles of Thy1.2-AMHTg/0 mice.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

The findings were shown only in one species and additional research will be required to determine generalizability to other species.

WIDER IMPLICATIONS OF THE FINDINGS

This study is consistent with prior studies showing that Amh-/- mice have increased primordial follicle activation but these new findings demonstrate that AMH-mediated preantral follicle atresia is a predominant cause of the increased small antral follicle counts in Amh-/- mice. This suggests that the role of AMH is not to conserve the ovarian reserve to prolong fertility, but instead to prevent the antral follicle pool from becoming too large. While this study may demonstrate a new function for AMH, the biological purpose of this function requires further investigation, particularly in mono-ovulatory species.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by the Health Research Council of New Zealand and the University of Otago. No competing interests to declare.

Insulin-like peptide 5 (INSL5) positively correlates with anti-Müllerian hormone (AMH) in women with the polycystic ovary syndrome: a case-control study

BACKGROUND

Insulin-like peptide 5 (INSL5) is involved in both reproductive and metabolic processes in polycystic ovary syndrome (PCOS). This study aimed to evaluate the relationship between INSL5 and anti-Müllerian hormone (AMH).

METHODS

A retrospective case-control study was conducted in a university-based reproductive centre between December 2019 and January 2021. We included 117 women with PCOS and 100 healthy subjects from Zhejiang Province. All subjects were divided into four groups (1st-4th) based on quartiles of serum INSL5 levels. Serum INSL5 concentration was assayed using an enzyme-linked immunosorbent assay.

RESULTS

A significant direct association was observed between serum INSL5 and AMH levels in women with PCOS. The mean AMH level in the 1st-4th INSL5 level quartiles were 4.64, 5.20, 6.46, and 9.48 ng/ml, respectively (P < 0.001). After adjusting for age, body mass index, metabolic indices, and serum levels of oestradiol and total testosterone, AMH levels remained positively and significantly associated with INSL5 levels (P for trend < 0.001). The diagnostic value of AMH was better than that of INSL5.

CONCLUSIONS

INSL5 and AMH levels were significantly correlated and elevated in women with PCOS. INSL5 and AMH might be associated with increased androgen secretion and chronic anovulation in PCOS.

Key signalling pathways underlying the aetiology of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a common endocrine condition characterised by a range of reproductive, endocrine, metabolic and psychological abnormalities. Reports estimate that around 10% of women of reproductive age are affected by PCOS, representing a significant prevalence worldwide, which poses a high economic health burden. As the origin of PCOS remains largely unknown, there is neither a cure nor mechanism-based treatments leaving patient management suboptimal and focused solely on symptomatic treatment. However, if the underlying mechanisms underpinning the development of PCOS were uncovered then this would pave the way for the development of new interventions for PCOS. Recently, there have been significant advances in our understanding of the underlying pathways likely involved in PCOS pathogenesis. Key insights include the potential involvement of androgens, insulin, anti-Müllerian hormone and transforming growth factor beta in the development of PCOS. This review will summarise the significant scientific discoveries on these factors that have enhanced our knowledge of the mechanisms involved in the development of PCOS and discuss the impact these insights may have in shaping the future development of effective strategies for women with PCOS.

The insulin-like growth factor and its players: their functions, significance, and consequences in all aspects of ovarian physiology

Background

Insulin-like growth factor (IGF) has unique and well-known functions in female fertility, according to documents reporting improved yield of oocytes, reinforced quality of the embryo, and enhanced live births with simultaneous reduction of miscarriage. However, there is no detailed information on the bio-mechanisms linking such clinical differences.

Main body

IGF and its receptors are expressed in a variety of tissues in the reproductive system such as granulosa cells, oocytes, and theca cells. Hence, the development of female gametes may be directly regulated by IGF, thereby affecting gamete quality and so its competence for implantation. IGF is a central player in changing the fate of cells during survival and proliferation through the modulation of leading signaling pathways, including Jak/STAT, MAP kinase/ERK, and PI3K/Akt, and subsequent impacts on steroidogenesis and cell division.

Conclusion

The current review aims to scrutinize the performance of IGF to regulate the normal ovarian, and its impacts on cell signaling pathways and resulting alterations in steroidogenesis and cell proliferation. The function of IGF and its receptor has been reviewed in female fertility at both molecular and biochemical levels.

2,3,5,4′-Tetrahydroxystilbene-2-O-β-D-Glucoside improves female ovarian aging

Reduced fertility associated with normal aging may reflect the over-maturity of oocytes. It is increasingly important to reduce aging-induced infertility since recent trends show people marrying at later ages. 2,3,5,4′-Tetrahydroxystilbene-2-O-β-D-glucoside (THSG), a polyphenol extracted from Polygonum multiflorum, has been reported to have anti-inflammatory and anti-aging properties. To evaluate whether THSG can reduce aging-related ovarian damage in a female mouse model of aging, THSG was administered by gavage at a dose of 10 mg/kg twice weekly, starting at 4 weeks of age in a group of young mice. In addition, the effect of THSG in a group of aged mice was also studied in mice starting at 24 weeks of age. The number of oocytes in the THSG-fed group was higher than in the untreated control group. Although the percentage of secondary polar bodies (PB2) decreased during aging in the THSG-fed group, it decreased much more slowly than in the age-matched control group. THSG administration increased the quality of ovaries in young mice becoming aged. Western blotting analyses also indicated that CYP19, PR-B, and ER-β expressions were significantly increased in 36-week-old mice. THSG also increased oocyte numbers in aged mice compared to mice without THSG fed. Studies of qPCR and immunohistochemistry (IHC) analyses of ovaries in the aged mice groups were conducted. THSG increased gene expression of anti-Müllerian hormone (AMH), a biomarker of oocyte number, and protein accumulation in 40-week-old mice. THSG increased the expression of pgc1α and atp6, mitochondrial biogenesis-related genes, and their protein expression. THSG also attenuated the fading rate of CYP11a and CYP19 associated with sex hormone synthesis. And THSG maintains a high level of ER-β expression, thereby enhancing the sensitivity of estrogen. Our findings indicated that THSG increased or extended gene expression involved in ovarian maintenance and rejuvenation in young and aged mice. On the other hand, THSG treatments significantly maintained oocyte quantity and quality in both groups of young and aged mice compared to each age-matched control group. In conclusion, THSG can delay aging-related menopause, and the antioxidant properties of THSG may make it suitable for preventing aging-induced infertility.

Proteolytic activation of anti-Müllerian hormone is suppressed in adolescent girls

PURPOSE

The ratio of the anti-Müllerian hormone (AMH) precursor (proAMH) to active AMH (AMH_N,C) is higher in childhood than in adulthood but has never been quantified during adolescence. The ratio of proAMH to total AMH (AMH prohormone index, API) was examined during the puberty in healthy girls. The API was also compared between girls with and without polycystic ovary syndrome (PCOS) to determine if there were differences that could assist in PCOS diagnosis during adolescence.

METHODS

Total AMH and proAMH were measured by immunoassay in a single-centre, cross-sectional observational study; 61 controls and 29 girls with PCOS were included in the study (age range 8-21 years). The API was calculated as proAMH as a percentage of total AMH. Differences in API between control and PCOS subjects and across age-groups were examined by Welch's ANOVA. The relationship between API and a range of metabolic parameters was examined by Pearson correlation.

RESULTS

The API in healthy females increased between the ages of 10~15 years and declined from 15~20 years (p < 0.001). The API was negatively correlated with body mass index in the control (p = 0.04) and PCOS groups (p = 0.007). The API was associated with factors related to adiposity and lipid metabolism. The API was not significantly different in control girls and girls with PCOS.

CONCLUSIONS

Higher API during adolescence suggests that proteolytic activation of proAMH is suppressed during this life stage. API was not different between control girls and girls with PCOS indicating that it is not useful in diagnosis of PCOS during adolescence.

Chronic superphysiologic AMH promotes premature luteinization of antral follicles in human ovarian xenografts

Anti-Müllerian hormone (AMH) is produced by growing ovarian follicles and provides a diagnostic measure of reproductive reserve in women; however, the impact of AMH on folliculogenesis is poorly understood. We cotransplanted human ovarian cortex with control or AMH-expressing endothelial cells in immunocompromised mice and recovered antral follicles for purification and downstream single-cell RNA sequencing of granulosa and theca/stroma cell fractions. A total of 38 antral follicles were observed (19 control and 19 AMH) at long-term intervals (>10 weeks). In the context of exogenous AMH, follicles exhibited a decreased ratio of primordial to growing follicles and antral follicles of increased diameter. Transcriptomic analysis and immunolabeling revealed a marked increase in factors typically noted at more advanced stages of follicle maturation, with granulosa and theca/stroma cells also displaying molecular hallmarks of luteinization. These results suggest that superphysiologic AMH alone may contribute to ovulatory dysfunction by accelerating maturation and/or luteinization of antral-stage follicles.

The putative roles of FSH and AMH in the regulation of oocyte developmental competence: from fertility prognosis to mechanisms underlying age-related subfertility

BACKGROUND

Fertility loss during female ageing is associated with increasing basal FSH and decreasing anti-Müllerian hormone (AMH) concentrations, together with compromised oocyte quality, presumably due to increased oxidative stress (OS) and DNA damage, as well as reduced metabolic and meiotic competences. Basal FSH and AMH circulatory concentrations have been broadly utilized as IVF success predictors, regardless of fluctuations in prognostic accuracy; basal FSH and AMH perform better in pre-advanced maternal age (AMA: >35 years) and AMA patients, respectively. The relationships between FSH and AMH intrafollicular levels and IVF outcomes suggest, nevertheless, that both hormones regulate oocyte competence, supporting the hypothesis that changes in FSH/AMH levels cause, at least in part, oocyte quality degradation during ageing. To understand the reasons behind the fluctuations in FSH and AMH prognostic accuracies and to clarify their participation in mechanisms determining oocyte competence and age-related subfertility, a deeper knowledge of the regulation of FSH and AMH intrafollicular signalling during the female reproductive lifespan, and of their effects on the cumulus-oocyte complex, is required.

OBJECTIVE AND RATIONALE

An extensive body of information on the regulation of FSH and AMH intrafollicular availability and signalling, as well as on the control of folliculogenesis and oocyte metabolism, has been accumulated. However, these datasets have been explored within the relatively narrow boundaries of their specific subjects. Given the aforementioned gaps in knowledge and their clinical relevance, herein we integrate clinical and basic data, within a wide biological perspective, aiming to shed light on (i) the reasons for the variability in the accuracy of serum FSH and AMH as fertility markers, and on (ii) the potential roles of these hormones in mechanisms regulating oocyte quality, particularly those associated with ageing.

SEARCH METHODS

The PubMed database encompassing the period between 1960 and 2021 was searched. Principal search terms were FSH, FSH receptor, AMH, oocyte, maternal age, cumulus, transzonal projections (TZPs), actin, OS, redox, reactive oxygen species, mitochondria, DNA damage, DNA repair, aneuploidy, spindle, meiosis, gene expression, transcription, translation, oocyte secreted factors (OSFs), cAMP, cyclic guanosine monophosphate, natriuretic peptide C, growth differentiation factor 9, bone morphogenetic protein 15 and fibroblast growth factor.

OUTCOMES

Our analysis suggests that variations in the accuracy of fertility prognosis reflect a modest association between circulatory AMH levels and oocyte quality as well as increasing basal FSH inter-cycle variability with age. In addition, the basic and clinical data articulated herein support the hypothesis that increased intrafollicular FSH levels, as maternal age advances, may override the physiological protective influences of AMH and OSFs against excessive FSH signalling in cumulus cells. This would result in the disruption of oocyte homeostasis via reduced TZP-mediated transfer of cumulus-derived molecules essential for meiotic competence, gene expression, redox activity and DNA repair.

WIDER IMPLICATIONS

In-depth data analysis, encompassing a wide biological perspective has revealed potential causative mechanisms of age-related subfertility triggered by alterations in FSH/AMH signalling during the female reproductive life. Insights from new mechanistic models arising from this analysis should contribute to advancing our comprehension of oocyte biology in humans and serve as a valuable reference for novel AMA subfertility treatments aimed at improving oocyte quality through the modulation of AMH/FSH action.

Oocyte quality following in vitro follicle development†

In vitro follicle development (IVFD) is an adequate model to obtain basic knowledge of folliculogenesis and provides a tool for ovarian toxicity screening. IVFD yielding competent oocytes may also offer an option for fertility and species preservation. To promote follicle growth and oocyte maturation in vitro, various culture systems are utilized for IVFD in rodents, domestic animals, wild animals, nonhuman primates, and humans. Follicle culture conditions have been improved by optimizing gonadotropin levels, regulatory factors, nutrient supplements, oxygen concentration, and culture matrices. This review summarizes quality assessment of oocytes generated from in vitro-developed antral follicles from the preantral stage, including oocyte epigenetic and genetic profile, cytoplasmic and nuclear maturation, preimplantation embryonic development following in vitro fertilization, as well as pregnancy and live offspring after embryo transfer. The limitations of oocyte quality evaluation following IVFD and the gaps in our knowledge of IVFD to support proper oocyte development are also discussed. The information may advance our understanding of the requirements for IVFD, with a goal of producing competent oocytes with genetic integrity to sustain embryonic development resulting in healthy offspring.

Translational Physiology of Anti-Müllerian Hormone: Clinical Applications in Female Fertility Preservation and Cancer Treatment

Background

Whilst the ability of AMH to induce the regression of the Müllerian ducts in the male fetus is well appreciated, AMH has additional biological actions in relation to steroid biosynthesis and ovarian follicle dynamics. An understanding of the physiology of AMH illuminates the potential therapeutic utility of AMH to protect the ovarian reserve during chemotherapy and in the treatment of female malignancies. The translation of the biological actions of AMH into clinical applications is an emerging focus of research, with promising preliminary results.

Objective and Rationale

Studies indicate AMH restrains primordial follicle development, thus administration of AMH during chemotherapy may protect the ovarian reserve by preventing the mass activation of primordial follicles. As AMH induces regression of tissues expressing the AMH receptor (AMHRII), administration of AMH may inhibit growth of malignancies expressing AMHR II. This review evaluates the biological actions of AMH in females and appraises human clinical applications.

Search Methods

A comprehensive search of the Medline and EMBASE databases seeking articles related to the physiological functions and therapeutic applications of AMH was conducted in July 2021. The search was limited to studies published in English.

Outcomes

AMH regulates primordial follicle recruitment and moderates sex steroid production through the inhibition of transcription of enzymes in the steroid biosynthetic pathway, primarily aromatase and 17α-hydroxylase/17,20-lyase. Preliminary data indicates that administration of AMH to mice during chemotherapy conveys a degree of protection to the ovarian reserve. Administration of AMH at the time of ovarian tissue grafting has the potential to restrain uncontrolled primordial follicle growth during revascularization. Numerous studies demonstrate AMH induced regression of AMHR II expressing malignancies. As this action occurs via a different mechanism to traditional chemotherapeutic agents, AMH has the capacity to inhibit proliferation of chemo-resistant ovarian cancer cells and cancer stem cells.

Wider Implications

To date, AMH has not been administered to humans. Data identified in this review suggests administration of AMH would be safe and well tolerated. Administration of AMH during chemotherapy may provide a synchronistic benefit to women with an AMHR II expressing malignancy, protecting the ovarian reserve whilst the cancer is treated by dual mechanisms.

Enhancing in vitro oocyte maturation competence and embryo development in farm animals: roles of vitamin-based antioxidants – a review

Oocyte/embryo in vitro culture is one of the most important assisted reproductive technologies used as a tool for maintaining genetic resources biodiversity and the inheritance of valuable genetic resources through generations. The success of such processes affects the final goal of the in vitro culture, getting viable and healthy offspring. In common in vitro oocyte maturation and/or embryo development techniques, the development of oocytes/embryos is carried out at 5% carbon dioxide and roughly 20% atmosphere-borne oxygen ratios in cell culture incubators due to their reduced cost in comparison with low atmospheric oxygen-tension incubators. These conditions are usually accompanying by the emergence of reactive oxygen species (ROS), which can extremely damage cell membrane integrity and other vital cellular organelles, as well as genetic material. The present review mainly focuses on the antioxidant roles of different vitamins on in vitro oocyte maturation competence and embryo development in farm animals. Because, the conditions of in vitro embryo production (IVEP) are usually accompanying by the emergence of reactive oxygen species (ROS), which can extremely damage cell membrane integrity and other vital cellular organelles as well as genetic material. The use of antioxidant agents may prevent the extreme augmentation of ROS generation and enhance in vitro matured oocyte competence and embryo development. Therefore, this review aimed to provide an updated outline of the impact of antioxidant vitamin (Vit) supplementations during in vitro maturation (IVM) and in vitro fertilization (IVF) on oocyte maturation and consequent embryo development, in various domestic animal species. Thus, the enrichment of the culture media with antioxidant agents may prevent and neutralize the extreme augmentation of ROS generation and enhance the in vitro embryo production (IVEP) outcomes.

Single-cell transcriptome and cell-specific network analysis reveal the reparative effect of neurotrophin-4 in preantral follicles grown in vitro

BACKGROUND

In-vitro-grow (IVG) of preantral follicles is essential for female fertility preservation, while practical approach for improvement is far from being explored. Studies have indicated that neurotrophin-4 (NT-4) is preferentially expressed in human preantral follicles and may be crucial to preantral follicle growth.

METHODS

We observed the location and expression of Tropomyosin-related kinase B (TRKB) in human and mouse ovaries with immunofluorescence and Western blot, and the relation between oocyte maturation and NT-4 level in follicular fluid (FF). Mice model was applied to investigate the effect of NT-4 on preantral follicle IVG. Single-cell RNA sequencing of oocyte combined with cell-specific network analysis was conducted to uncover the underlying mechanism of effect.

RESULTS

We reported the dynamic location of TRKB in human and mouse ovaries, and a positive relationship between human oocyte maturation and NT-4 level in FF. Improving effect of NT-4 was observed on mice preantral follicle IVG, including follicle development and oocyte maturation. Transcriptome analysis showed that the reparative effect of NT-4 on oocyte maturation might be mediated by regulation of PI3K-Akt signaling and subsequent organization of F-actin. Suppression of advanced stimulated complement system in granulosa cells might contribute to the improvement. Cell-specific network analysis revealed NT-4 may recover the inflammation damage induced by abnormal lipid metabolism in IVG.

CONCLUSIONS

Our data suggest that NT-4 is involved in ovarian physiology and may improve the efficiency of preantral follicle IVG for fertility preservation.

Insulin resistance and potential modulators of ovarian reserve in young reproductive-aged women with obesity and type 1 diabetes

INTRODUCTION

Both obesity and diabetes play a significant role in reproductive disorders in women and insulin resistance (IR) is a confirmed trait d'union. We evaluated the relationship between IR and an established ovarian reserve biomarker such as anti-mullerian hormone (AMH) together with other potential modulators of ovarian physiology (adiponectin and kisspeptin) in young reproductive-aged group women with obesity and type 1 diabetes (T1D).

PATIENTS AND METHODS

We recruited 32 female youths: 14 of them presented with T1D (14.6 ± 2.6 years) and 18 with obesity (15.1 ± 2.6 years). The control group included 20 age-matched normal weight females. Each patient underwent physical examination and hormonal assessment. AMH, kisspeptin and adiponectin levels were also measured. IR was calculated as the homeostasis model assessment for insulin resistance (HOMA-IR) and the glucose disposal rate (eGDR) in patients with obesity and with T1D, respectively.

RESULTS

adiponectin and kisspeptin levels were significantly different into groups (p ≤ .001), whereas AMH levels were not. Adiponectin values were higher in controls compared to patients with obesity (p < .001) and T1D (p = .02). Kisspeptin levels were lower in controls compared to patients with obesity (p = .001), without reaching statistical significance when compared to T1D (p = .06). IR was associated with lower adiponectin and higher kisspeptin levels (p < .001 and p = .02, respectively), but not with AMH.

CONCLUSIONS

IR displays a relationship with adiponectin and kisspeptin in young reproductive-aged women with obesity and T1D. Interventions to correct IR in adolescents could be part of an early approach to prevent reproductive disorders and to promote factors associated with longevity in adult women.

Dysregulation of anti-Mullerian hormone expression levels in mural granulosa cells of FMR1 premutation carriers

FMR1 premutation (55–200 CGG repeats) results in fragile X-associated primary ovarian insufficiency (FXPOI). We evaluated expression levels of folliculogenesis-related mediators, follicle-stimulating hormone (FSH) receptor and anti-Mullerian hormone (AMH), to gain insights into the mechanisms underlying the reduced ovarian function. Mural granulosa cells (MGCs) were collected from FMR1 premutation carriers and noncarriers undergoing IVF treatments. At baseline, MGCs of carriers demonstrated significantly higher mRNA expression levels of AMH (3.5 ± 2.2, n = 12 and 0.97 ± 0.5, n = 17, respectively; p = 0.0003) and FSH receptor (5.6 ± 2.8 and 2.7 ± 2.8, respectively; p = 0.02) and higher AMH protein expression on immunostaining. Accordingly, FMR1 premutation-transfected COV434 cells exhibited higher AMH protein expression than COV434 cells transfected with 20 CGG repeats. We conclude that FMR1 premutation may lead to dysregulation of AMH expression levels, probably due to a compensatory mechanism. Elucidating the pathophysiology of FXPOI may help in early detection of ovarian dysfunction and tailoring IVF treatments to FMR1 premutation carriers.

Capitalizing on transcriptome profiling to optimize and identify targets for promoting early murine folliculogenesis in vitro

In vitro ovarian follicle culture is an active area of research towards providing fertility options for survivors of childhood cancer. Late-stage murine follicles (multilayer secondary and onwards) can be cultured successfully to maturity to obtain a meiotically competent oocyte for fertilization, but primordial and primary follicles usually die in culture because many key components of early follicle development are still unknown and difficult to mimic in vitro. To engineer a biomimetic three-dimensional culture system with high efficacy and reproducibility for the clinic, detailed mechanisms of early folliculogenesis must be uncovered. Previous studies have shown that primary murine follicles co-cultured in groups, in contrast to single follicles cultured in isolation, can reach preovulatory size and produce competent oocytes, but the factors accounting for the synergy of follicle co-culture are still unknown. To probe the underlying mechanisms of successful follicle co-culture, we conducted a time-course experiment for murine follicles encapsulated in 0.3% alginate hydrogels and compared between two conditions: groups of 5 (5X) versus groups of 10 (10X). For every 2 days during the course of 12 days, follicles were dissociated and somatic cells were isolated for microarray-based gene expression analysis (n = 380 follicles for 5X and n = 430 follicles for 10X). Gene activities in follicles co-cultured in larger groups (10X) had a distinct transcriptomic profile of key genes and pathways such as prolactin signaling and angiogenesis-related genes when compared to cells from follicles co-cultured in the smaller cohort (5X). To benchmark the results for follicles grown in culture, we compared our microarray data to data from murine follicles freshly isolated from the ovary at comparable stages of development previously published by Bernabé et al. Comparison of these datasets identified similarities and differences between folliculogenesis in the native microenvironment and the engineered in vitro system. A more detailed understanding of follicle growth in vitro will not only allow for better culture methods but also advance the field towards providing improved fertility options for survivors of childhood cancer.

Matrix-free 3D culture supports human follicular development from the unilaminar to the antral stage in vitro yielding morphologically normal metaphase II oocytes

STUDY QUESTION

Can group culture with stage-specific anti-Müllerian hormone (AMH) modulation support human follicular development and oocyte maturation in vitro?

SUMMARY ANSWER

In the presence of FSH, AMH supplementation at the secondary-to-early antral stage followed by AMH depletion promotes the coordinated growth and function of human follicles during group culture, thereby yielding mature oocytes.

WHAT IS KNOWN ALREADY

Stage-specific AMH modulation promotes in-vitro development of nonhuman primate follicles. The group culture method supports nonhuman primate follicle growth from the primary to antral stage, producing developmentally competent oocytes.

STUDY DESIGN, SIZE, DURATION

Ovarian tissue samples were collected from 19 patients of reproductive age (22-47 years old having menstrual cycles) who underwent oophorectomy or hysterectomy for clinical purposes. Tissue pieces were cultured in a matrix-free system for 3 weeks followed by isolation of follicles for the subsequent 6-week individual or group culture.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Pieces of ovarian cortical tissue were cultured to support primordial follicle activation and early-stage follicle growth. Secondary follicles isolated from cultured tissue were then randomly assigned to two groups for individual culture: control and AMH modulation, i.e., recombinant human AMH protein supplementation during the secondary-to-early antral stage followed by the addition of neutralizing anti-human AMH antibody. Secondary follicles were also cultured in groups with the same AMH modulation. Follicle survival, growth, steroid hormone and paracrine factor production, steroidogenic protein expression, as well as oocyte maturation and morphology were assessed.

MAIN RESULTS AND THE ROLE OF CHANCE

Follicles grew to the secondary stage during 3 weeks of ovarian tissue culture. In-vitro-developed follicles expressed AMH and levels of secreted AMH increased (P < 0.05) in the culture media over time. Secondary follicles isolated from cultured ovarian tissue survived and grew to the antral stage during 6 weeks of individual follicle culture. In-vitro-developed antral follicles produced granulosa and theca cell-derived steroid hormones and paracrine factors, which were detectable in the culture media. Germinal vesicle oocytes obtained from cultured follicles exhibited a perinucleolar chromatin rim configuration. AMH modulation did not alter follicle survival or oocyte maturation relative to those of the control follicles. However, follicle diameters, as well as steroid hormone and paracrine factor production, increased (P < 0.05) in the AMH-modulation group compared with the control group. Secondary follicles isolated from cultured ovarian tissue formed aggregates and grew to the antral stage during 6 weeks of group culture. In-vitro-developed antral follicles expressed steroidogenic enzymes and secreted steroid hormones were detectable in the culture media. Oocytes obtained from cultured follicle aggregates with AMH-modulation progressed to the metaphase II stage after IVM, containing a normal-sized first polar body and meiotic spindle. Oocytes exhibited a typical ultrastructure.

LIMITATIONS, REASONS FOR CAUTION

Follicles were obtained from fresh ovarian tissue of adult patients. Oocyte maturation rates were relatively low and oocytes were assessed by morphological evaluation. Owing to the lack of a control group, the beneficial effects of AMH modulation remained undetermined for the group culture in this study.

WIDER IMPLICATIONS OF THE FINDINGS

Stage-specific AMH modulation supports human follicular development in the matrix-free group culture, which is consistent with previously reported AMH actions on growing follicles in nonhuman primates. Oocytes generated by in-vitro-developed follicles achieve meiotic maturation with a typical morphology and ultrastructure, which supports in-vitro follicle maturation as a potential approach for fertility preservation in women.

STUDY FUNDING/COMPETING INTEREST(S)

NICHD R01HD082208 and NIH Office of the Director P51OD011092. The authors have no competing interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Polycystic Ovary Syndrome: Pathophysiology, Presentation and Treatment a Mini-Review Article

Polycystic ovary syndrome (PCOS) is a common heterogeneous disorder which is known as syndrome. The term ‘syndrome’ refers to a collection of clinical features or a phenotype. The specific features of the PCOS phenotype include clinical signs of androgen excess, elevated serum androgen concentrations, irregular menses, and infertility. It is common heterogenous disorder which affects women with different clinical presentations. In the basis of this disease is hormonal imbalance, such as insulin resistance and hyperinsulinemia. This review was based on searching all the available literature in the next databases: Pubmed, ClinicalTrials, Embase, Medline Complete, Web of Science, Cochrane Library, the Chinese Science and Technology Periodical Database (VIP), WanFang Database (Chinese Ministry of Science & Technology). The search terms included hormonal and metabolic aspects, therapy of PCOS, polycystic ovary syndrome, PCOS.We included only randomized clinical intervention trials in young women published in last five years and included 12 articles in our review analysis. More research is needed to clarify the complex pathophysiology of PCOS. No single test is currently available for its diagnosis. Additionally, once diagnosis is established, the options for treatment are of limited number and effectiveness because they target only the symptoms of PCOS. Finally, patients with PCOS have higher rates of metabolic complications, such as cardiovascular disease, but their impact on mortality is not clear. Therefore, more prospective epidemiologic studies on the topic are necessary.

Characterization of Anti-Müllerian Hormone (AMH) Gene in Buffaloes and Goats

The Anti-Müllerian Hormone (AMH) is a member of the transforming growth factor beta (TGF-β) superfamily, playing a significant role in cell proliferation, differentiation and apoptosis. In females, AMH is secreted throughout their reproductive life span from ovaries, whereas in males it is secreted by gonadal cells at a very early stage of testicular development. AMH is a promising marker of ovarian reserve in women and can be used to measure the female reproductive lifespan. In the present study, we cloned and sequenced the GC rich AMH gene from Indian riverine buffalo (Bubalus bubalis) and goat (Capra hircus). Obtained sequences were compared to the AMH sequences of other mammals, and corresponding amino acid sequences revealed that the caprine and bovine AMH sequences are more closely related to each other than to those of other mammals. Furthermore, we analyzed the chromosomal localization of AMH genes in mammalian species to understand potential syntenic relationship. The AMH gene is localized between the sequences for the SF3A and JSRP1 genes and maintains this precise location in relation to other nearby genes. The dN/dS ratio of AMH gene did not indicate any pressure for either positive or negative selection; thus, the physiological function of the AMH gene in the reproduction of these two ruminant species remains very vital. Similar to other mammals, the AMH gene may be an important indicator for regulating female reproductive biology function in bovine, cetacean, caprine, and camelidae.

Ovarian Fragmentation and AKT Stimulation for Expansion of Fertile Lifespan

Since the first baby was born after in vitro fertilization, the female infertility treatment has been well-developed, yielding successful outcomes. However, successful pregnancies for patients with premature ovarian insufficiency and diminished ovarian reserve are still difficult and diverse therapies have been suggested to improve the chances to have their genetically linked offspring. Recent studies demonstrated that the activation Akt pathway by using a phosphatase and tensin homolog enzyme inhibitor and a phosphatidylinositol-3 kinase stimulator can activate dormant primordial follicles in both mice and human ovaries. Subsequent researches suggested that the disruption of Hippo signaling pathway by ovarian fragmentation increased the expression of downstream growth factors and secondary follicle growth. Based on the combination of ovarian fragmentation and Akt stimulation, the in vitro activation (IVA) approach has resulted in successful follicle growth and live births in premature ovarian insufficiency patients. The approach with disruption of Hippo signaling only was also shown to be effective for treating poor ovarian responders with diminishing ovarian reserve, including advanced age women and cancer patients undergoing sterilizing treatments. This review aims to summarize the effectiveness of ovarian fragmentation and Akt stimulation on follicle growth and the potential of IVA in extending female fertile lifespan.

High Variability of Molecular Isoforms of AMH in Follicular Fluid and Granulosa Cells From Human Small Antral Follicles

Anti-Müllerian hormone (AMH) is a member of the TGF-β superfamily produced by follicular granulosa cells (GCs) in women from late gestation to the end of reproductive life. AMH is thought to inhibit aromatase (i.e., CYP19) expression and decrease the conversion of androgens to oestrogens, especially in small antral follicles before dominance is achieved. Thus, AMH acts as a gatekeeper of ovarian steroidogenesis. However, the exact function and processing of AMH has not been fully elucidated. The present study measured and determined AMH isoforms in human follicular fluid (FF) from small antral follicles and in human GCs using four ELISAs, western blot, and immunofluorescence analysis. We evaluated the presence of the following isoforms: full-length AMH precursor (proAMH), cleaved associated AMH (AMH_N,C), N-terminal pro-region (AMH_N), and active C-terminal (AMH_C) AMH. A negative correlation between follicle diameter and the AMH forms was detected. Moreover, western blot analysis detected various AMH forms in both FFs and GCs, which did not match our consensus forms, suggesting an unknown proteolytic processing of AMH. The presence of these new molecular weight isoforms of AMH differs between individual follicles of identical size in the same woman. This study detected several AMH forms in FF and GCs obtained from human small antral follicles, which suggests that intrafollicular processing of AMH is complex and variable. Thus, it may be difficult to develop an antibody-based AMH assay that detects all AMH isoforms. Furthermore, the variability between follicles suggests that designing a recombinant AMH standard will be difficult.

New Human Follitropin Preparations: How Glycan Structural Differences May Affect Biochemical and Biological Function and Clinical Effect

It is well accepted that pituitary follitropin is secreted into the circulation as a mixture of variants, which differ not in primary structure but rather at the level of glycosylation. These glycosidic forms vary in the number of glycosylation sites filled, complexity of glycosidic chains, and sialylation and sulfation. It is generally agreed that high sialylation, 2,3 sialic acid capping of terminal N-acetyl galactosamine or galactose leads to longer circulating half-life, by blocking binding of asialoglycoprotein receptor (ASGPR) in the liver. In contrast, 2,6 sialic acid found in humans does not prevent recognition of galactose and N-acetyl galactosamine by ASGPR. Few studies on clinical outcomes comparing differences in sialylation of follitropin found in commercially available preparations are available. Thus, there is a clear need for a consortium of open data to address this unmet need. Recently, FSH glycosylation, primarily on the β-subunit, which varies as women age, has emerged as a key modifier of follitropin action, with profound biological effects in vivo in animal models. To date, limited information of recombinant follitropin hormone preparations is available. Thus, most of the studies with FSH that is well characterized biochemically have been done in vitro, with engineered non gonadal host cells bearing recombinant receptors or in animal models. Since limited studies in human granulosa cells are available, a question is whether structural differences in glycosylation in commercially available follitropin affects biological function and clinical effect in humans. The presence of fucose, for example, has not been studied greatly even though, in the case of antibody therapy it has been shown to have a large effect on antibody targeting. This review on glycosidic variability of follitropin from the biochemical/structural point of view reflects on this question and presents an assessment in the context of available published data. If clinical differences are to be expected or not, the readers will have a better understanding of the evidence for and limitations of such expectations.

Stage-dependent actions of antimüllerian hormone in regulating granulosa cell proliferation and follicular function in the primate ovary

OBJECTIVE

To study the direct action and physiological role of antimüllerian hormone (AMH) in regulating ovarian follicular development and function in vivo in primates.

DESIGN

Animals were assigned to six treatment sequences in a crossover design study. Intraovarian infusion was performed during the follicular phase of the menstrual cycle with agents including: control vehicle; recombinant human AMH (rhAMH); and neutralizing anti-human AMH antibody (AMHAb). Before ovariectomy after the final treatment, the animals received intravenous injections of bromodeoxyuridine (BrdU).

SETTING

National primate research center.

ANIMALS

Adult female rhesus macaques (Macaca mulatta).

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Cycle length, follicle cohorts, and serum steroid levels were assessed. Ovarian histology, as well as granulosa cell (GC) proliferation and oocyte viability, were evaluated.

RESULTS

In vehicle-infused ovaries, a dominant follicle was observed at midcycle E2 peak. However, rhAMH-treated ovaries exhibited an increased number of small antral follicles, whereas AMHAb-treated ovaries developed multiple large antral follicles. Serum E2 levels in the follicular phase decreased after rhAMH infusion and increased after AMHAb infusion. The rhAMH infusion increased serum T levels. Whereas early-growing follicles of rhAMH-treated ovaries contained BrdU-positive GCs, antral follicles containing BrdU-positive GCs were identified in AMHAb-treated ovaries. Autophagy was observed in oocytes of early-growing and antral follicles exposed to AMHAb and rhAMH, respectively.

CONCLUSIONS

AMH enhanced early-stage follicle growth, but prevented antral follicle development and function via its stage-dependent regulation of GC proliferation and oocyte viability. This study provides information relevant to the pathophysiology of ovarian dysfunction and the treatment of infertility.

Supportive techniques to investigate in vitro culture and cryopreservation efficiencies of equine ovarian tissue: A review

During the reproductive lifespan of a female, only a limited quantity of oocytes are naturally ovulated; therefore, the mammalian ovary possesses a substantial population of preantral follicles available to be handled and explored in vitro. Hence, the manipulation of preantral follicles enclosed in ovarian tissue aims to recover a considerable population of oocytes of high-value animals for potential application in profitable assisted reproductive technologies (ARTs). For this purpose, the technique of preantral follicle in vitro culture (IVC) has been the most common research tool, achieving extraordinary results with offspring production in the mouse model. Although promising outcomes have been generated in livestock animals after IVC of preantral follicles, the quantity and quality of embryo production with those oocytes are still poor. In recent years, the mare has become an additional model for IVC studies due to remarkable similarities with women and livestock animals regarding in vivo and in vitro ovarian folliculogenesis. For a successful IVC system, several factors should be carefully considered to provide an optimum culture environment able to support the viability and growth of preantral follicles enclosed in ovarian tissue. The cryopreservation of the ovarian tissue is another important in vitro manipulation technique that has been used to preserve the reproductive potential in humans and, in the future, may be used in highly valuable domestic animals or endangered species. Several improvements in cryopreservation protocols are necessary to support the utilization of ovarian tissue of different species in follow-up ARTs (e.g., ovarian fragment transplantation). This review aims to provide an update on the most current advances regarding supportive in vitro techniques used in equids to evaluate and manipulate preantral follicles and ovarian tissue, as well as methodological approaches used during IVC and cryopreservation techniques.

New insights into anti-Müllerian hormone role in the hypothalamic-pituitary-gonadal axis and neuroendocrine development

Research into the physiological actions of anti-Müllerian hormone (AMH) has rapidly expanded from its classical role in male sexual differentiation to the regulation of ovarian function, routine clinical use in reproductive health and potential use as a biomarker in the diagnosis of polycystic ovary syndrome (PCOS). During the past 10 years, the notion that AMH could act exclusively at gonadal levels has undergone another paradigm shift as several exciting studies reported unforeseen AMH actions throughout the Hypothalamic–Pituitary–Gonadal (HPG) axis. In this review, we will focus on these findings reporting novel AMH actions across the HPG axis and we will discuss their potential impact and significance to better understand human reproductive disorders characterized by either developmental alterations of neuroendocrine circuits regulating fertility and/or alterations of their function in adult life. Finally, we will summarize recent preclinical studies suggesting that elevated levels of AMH may potentially be a contributing factor to the central pathophysiology of PCOS and other reproductive diseases.

Early evaluation of survival of the transplanted ovaries through ultrasound molecular imaging via targeted nanobubbles

Schematic of AMH-targeted nanobubbles (NB_AMH) and their targeting ability to rat ovarian granulosa cells expressing AMH.

Polycystic Ovary Syndrome: Pathophysiology, Presentation, and Treatment With Emphasis on Adolescent Girls

Polycystic ovary syndrome (PCOS) is a heterogeneous disorder characterized by hyperandrogenism and chronic anovulation. Depending on diagnostic criteria, 6% to 20% of reproductive aged women are affected. Symptoms of PCOS arise during the early pubertal years. Both normal female pubertal development and PCOS are characterized by irregular menstrual cycles, anovulation, and acne. Owing to the complicated interwoven pathophysiology, discerning the inciting causes is challenging. Most available clinical data communicate findings and outcomes in adult women. Whereas the Rotterdam criteria are accepted for adult women, different diagnostic criteria for PCOS in adolescent girls have been delineated. Diagnostic features for adolescent girls are menstrual irregularity, clinical hyperandrogenism, and/or hyperandrogenemia. Pelvic ultrasound findings are not needed for the diagnosis of PCOS in adolescent girls. Even before definitive diagnosis of PCOS, adolescents with clinical signs of androgen excess and oligomenorrhea/amenorrhea, features of PCOS, can be regarded as being "at risk for PCOS." Management of both those at risk for PCOS and those with a confirmed PCOS diagnosis includes education, healthy lifestyle interventions, and therapeutic interventions targeting their symptoms. Interventions can include metformin, combined oral contraceptive pills, spironolactone, and local treatments for hirsutism and acne. In addition to ascertaining for associated comorbidities, management should also include regular follow-up visits and planned transition to adult care providers. Comprehensive knowledge regarding the pathogenesis of PCOS will enable earlier identification of girls with high propensity to develop PCOS. Timely implementation of individualized therapeutic interventions will improve overall management of PCOS during adolescence, prevent associated comorbidities, and improve quality of life.

Androgen potentiates the expression of FSH receptor and supports preantral follicle development in mice

Hyperandrogenism is one of the cardinal symptoms in polycystic ovary syndrome and plays a key role in the pathogenesis of polycystic ovary syndrome. However, the precise effects and mechanisms of excess androgen during follicular development are still unclear. Here we investigated the effects of androgen on mouse follicle development in vitro. Androgen did not affect the growth of follicles smaller than 160–180 μm in the presence of follicle-stimulating hormone (FSH). However, in the presence of low FSH, androgen supported the growth of follicles larger than 160–180 μm, a size at which growing follicles acquire FSH-dependency. Androgen did not change the mRNA expression of various growth-promoting factors but did increase mRNA expression of the FSH receptor. We suggest that androgen has a positive impact on follicle development by augmentation of the actions of FSH. Therefore, FSH-responsive but FSH-independent follicles grow in the presence of a certain level of FSH or androgen, and androgen compensates for FSH deficiency in FSH-dependent follicles.

Stage-specific modulation of antimüllerian hormone promotes primate follicular development and oocyte maturation in the matrix-free three-dimensional culture

OBJECTIVE

To study whether follicular growth and oocyte maturation can be improved by antimüllerian hormone (AMH) modulation at specific stages of follicular development.

DESIGN

Primary and secondary follicles were cultured in a matrix-free system and were assigned to the control group and the group with AMH supplementation during the preantral stage and neutralizing AMH antibody addition during the antral stage.

SETTING

National primate research center.

ANIMAL(S)

Adult, female rhesus macaques (Macaca mulatta).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Follicle survival, growth, steroid and paracrine factor production, and oocyte competence were evaluated. Follicles were assessed for expression of genes that are critical for gonadotropin signaling, cumulus cell glycolysis, and oocyte quality.

RESULT(S)

Primary follicles formed "organoids" and developed to the antral stage in group culture. AMH exposure during the preantral stage increased organoid diameters. Oocytes from the AMH-treated organoids had greater diameters and matured to the metaphase II (MII) stage. Secondary follicles developed to the antral stage during individual culture. The AMH exposure during the preantral stage and AMH antibody treatment during the antral stage increased follicle diameters, vascular endothelial growth factor and follistatin production, differentiation factor 9 expression, and oocyte diameters. The MII oocytes from the AMH-modulated group developed to the morula stage after IVF, with one to the blastocyst stage.

CONCLUSION(S)

AMH supplementation at the preantral stage and depletion at the antral stage enhanced primate follicular development and oocyte competence in vitro. The improved embryonic development supports in vitro follicle maturation as a potential approach for fertility preservation.

Chronic hyperandrogenemia in the presence and absence of a western-style diet impairs ovarian and uterine structure/function in young adult rhesus monkeys

STUDY QUESTION

Does chronic hyperandrogenemia beginning at menarche, in the absence and presence of a western-style diet (WSD), alter ovarian and uterine structure-function in young adult rhesus monkeys?

SUMMARY ANSWER

Phenotypic alterations in ovarian and uterine structure/function were induced by exogenous testosterone (T), and compounded in the presence of a WSD (T+WSD).

WHAT IS KNOWN ALREADY

Hyperandrogenemia is a well-established component of PCOS and is observed in adolescent girls, indicating a potential pubertal onset of disease symptoms. Obesity is often associated with hyperandrogenemia and it is hypothesized that metabolic dysfunction exacerbates PCOS symptoms.

STUDY DESIGN, SIZE, DURATION

Macaque females (n = 40) near the onset of menarche (~2.5 years of age) were assigned to a 2 by 2 factorial cohort design. Effects on reproductive characteristics were evaluated after 3 years of treatment.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Rhesus macaques (Macaca mulatta) were fed either a normal balanced diet (n = 20) or a WSD (n = 20). Additionally, implants containing cholesterol (n = 20) or T (n = 20) were implanted subcutaneously to elevate serum T approximately 5-fold. This resulted in treatment groups of controls (C), T, WSD and T+WSD (n = 10/group). Vaginal swabbing was performed daily to detect menses. After 3 years of treatment, daily serum samples from one menstrual cycle were assayed for hormone levels. Ovarian structure was evaluated in the early follicular phase by 3D/4D ultrasound. Uterine endometrial size and ovarian/luteal vascular function was also evaluated in subgroups (n = 6/group) in the late follicular and mid-luteal phases by 3D/4D ultrasound and contrast-enhanced ultrasound, respectively. Expression of steroid hormone receptors and markers of decidualization and endometrial receptivity were assessed in endometrial biopsies at mid-luteal phase.

MAIN RESULTS AND THE ROLE OF CHANCE

Approximately 90% of menstrual cycles appeared ovulatory with no differences in frequency or duration between groups. Serum estradiol (E2) levels during the early follicular phase were greatest in the T alone group, but reduced in T+WSD (P < 0.02). Serum LH was elevated in the T group (P < 0.04); however, there were no differences among groups in FSH levels (P > 0.13). Ovarian size at menses tended to be greater in the WSD groups (P < 0.07) and antral follicles ≥1 mm were more numerous in the T+WSD group (P < 0.05). Also, females in T and T+WSD groups displayed polycystic ovarian morphology (PCOM) at greater frequency than C or WSD groups (P < 0.01). Progesterone (P4) levels during the luteal phase were reduced in the T+WSD group compared to C and T groups (P < 0.05). Blood volume (BV) and vascular flow (VF) within the corpus luteum was reduced in all treatment groups compared to C (P < 0.01, P = 0.03), with the WSD alone group displaying the slowest BV and VF (P < 0.05). C and WSD groups displayed endometrial glands at mid-luteal phase with low estrogen receptor 1 (ESR1) and progesterone receptor (PGR) mRNA and immunohistochemical staining in the functionalis zone, but appreciable PGR in the stroma. In contrast, T and T+WSD treatment resulted in glands with less secretory morphology, high ESR1 expression in the glandular epithelium and low PGR in the stroma. Endometrial levels of TIMP3 and MMP26 mRNA and immunostaining were also decreased in the T and T+WSD groups, whereas AR expression was unchanged.

LARGE SCALE DATA

None.

LIMITATIONS, REASONS FOR CAUTION

Females are young adults, so effects could change as they reach prime reproductive age. The T level generated for hyperandrogenemia may be somewhat greater than the 3-4-fold increase observed in adolescent girls, but markedly less than those observed in male monkeys or adolescent boys.

WIDER IMPLICATIONS OF THE FINDINGS

Alterations to ovarian and uterine structure-function observed in T and, in particular, T+WSD-treated female macaques are consistent with some of the features observed in women diagnosed with polycystic ovary syndrome (PCOS), and suggest impaired fertility.

STUDY FUNDING/COMPETING INTEREST(S)

Research reported in this publication was supported by the Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD) of the National Institutes of Health (NIH) under Award Number P50HD071836 (to RLS). The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH. Additional funding was provided by Office of the Director, NIH under Award Number P51OD011092 (Support for National Primate Research Center). Authors declare no competing interests.

Growth Hormone and Insulin-Like Growth Factor Action in Reproductive Tissues

The role of growth hormone (GH) in human fertility is widely debated with some studies demonstrating improvements in oocyte yield, enhanced embryo quality, and in some cases increased live births with concomitant decreases in miscarriage rates. However, the basic biological mechanisms leading to these clinical differences are not well-understood. GH and the closely-related insulin-like growth factor (IGF) promote body growth and development via action on key metabolic organs including the liver, skeletal muscle, and bone. In addition, their expression and that of their complementary receptors have also been detected in various reproductive tissues including the oocyte, granulosa, and testicular cells. Therefore, the GH/IGF axis may directly regulate female and male gamete development, their quality, and ultimately competence for implantation. The ability of GH and IGF to modulate key signal transduction pathways such as the MAP kinase/ERK, Jak/STAT, and the PI3K/Akt pathway along with the subsequent effects on cell division and steroidogenesis indicates that these growth factors are centrally located to alter cell fate during proliferation and survival. In this review, we will explore the function of GH and IGF in regulating normal ovarian and testicular physiology, while also investigating the effects on cell signal transduction pathways with subsequent changes in cell proliferation and steroidogenesis. The aim is to clarify the role of GH in human fertility from a molecular and biochemical point of view.

Vitamin D3 Regulates Follicular Development and Intrafollicular Vitamin D Biosynthesis and Signaling in the Primate Ovary

There is an increasing recognition that vitamin D plays important roles in female reproduction. Recent studies demonstrated that 1α,25-dihydroxyvitamin D3 (VD3), the biologically active form of vitamin D, improved ovarian follicle survival and growth in vitro. Therefore, we investigated the direct effects of VD3 at the specific preantral and antral stages of follicular development, and tested the hypothesis that vitamin D receptor (VDR) and enzymes critical for vitamin D biosynthesis are expressed in the primate ovary. Fourteen adult rhesus macaques provided ovarian tissue. Secondary and antral follicles were isolated for PCR analysis on VDR, vitamin D3 25-hydroxylase, and 25-hydroxyvitamin D3-1α-hydroxylase. VDR protein localization was determined by immunohistochemistry on ovarian sections. Isolated secondary follicles were cultured under conditions of control and VD3 supplementation during the preantral or antral stage. Follicle survival, growth, steroid and anti-Müllerian hormone (AMH) production, as well as oocyte maturation were evaluated. In vivo- and in vitro-developed follicles were also assessed for genes that are critical for vitamin D biosynthesis and signaling, gonadotropin signaling, steroid and paracrine factor production, and oocyte quality. The mRNA encoding VDR, 25-hydroxylase, and 1α-hydroxylase was detectable in in vivo- and in vitro-developed preantral and antral follicles. The 25-hydroxylase was elevated in cultured follicles relative to in vivo-developed follicles, which further increased following VD3 exposure. VD3 treatment increased 1α-hydroxylase in in vitro-developed antral follicles. The absence of VD3 during culture decreased VDR expression in in vitro-developed antral follicles, which was restored to levels comparable to those of in vivo-developed antral follicles by VD3 supplementation. Positive immunostaining for VDR was detected in the nucleus and cytoplasm of granulosa cells and oocytes. While only survival was improved in preantral follicles treated with VD3, VD3 supplementation promoted both survival and growth of antral follicles with increased estradiol and AMH production, as well as oocyte maturation. Thus, Vitamin D biosynthesis and signaling systems are expressed in primate ovarian follicles. Our findings support a role for VD3 in regulating follicular development in a stage-dependent manner, as well as the intrafollicular vitamin D biosynthesis and signaling, directly in the ovary.

Direct actions of androgen, estrogen and anti-Müllerian hormone on primate secondary follicle development in the absence of FSH in vitro

STUDY QUESTION

What are effects of androgen, estrogen and anti-Müllerian hormone (AMH), independent of FSH action, on the development and function of primate follicles from the preantral to small antral stage in vitro?

SUMMARY ANSWER

Androgen and estrogen, but not AMH, promote follicle survival and growth in vitro, in the absence of FSH. However, their growth-promoting effects are limited to the preantral to early antral stage.

WHAT IS KNOWN ALREADY

FSH supports primate preantral follicle development in vitro. Androgen and estrogen augment follicle survival and growth in the presence of FSH during culture.

STUDY DESIGN SIZE, DURATION

Nonhuman primate model; randomized, control versus treatment groups. Rhesus macaque (n = 6) secondary follicles (n = 24 per animal per treatment group) were cultured for 5 weeks.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Follicles were encapsulated in 0.25% (w/v) alginate and cultured individually in modified alpha minimum essential media with (i) FSH (1 ng/ml; control), (ii) no FSH, (iii) no FSH + estradiol (E2; 100 pg/ml)/dihydrotestosterone (DHT; 50 ng/ml) and (iv) no FSH + AMH (50 ng/ml). In a second experiment, follicles were cultured with (i) FSH (1 ng/ml), (ii) no FSH, (iii) no FSH + E2 (1 ng/ml), (iv) no FSH + DHT (50 ng/ml) and (v) no FSH + E2/DHT. Follicle survival, antrum formation and growth pattern were evaluated. Progesterone (P4), E2 and AMH concentrations in culture media were measured.

MAIN RESULTS AND THE ROLE OF CHANCE

In the first experiment, FSH deprivation significantly decreased (P < 0.05) follicle survival rates in the no FSH group (16 ± 5%), compared to CTRL (66 ± 9%). E2/DHT (49 ± 5%), but not AMH (27 ± 8%), restored follicle survival rate to the CTRL level. Similarly, antrum formation rates were higher (P < 0.05) in CTRL (56 ± 6%) and E2/DHT groups (54 ± 14%), compared to no FSH (0 ± 0%) and AMH (11 ± 11%) groups. However, follicle growth rate after antrum formation and follicle diameter at week 5 was reduced (P < 0.05) in the E2/DHT group (405 ± 25 μm), compared to CTRL (522 ± 29 μm). Indeed, the proportion of fast-grow follicles at week 5 was higher in CTRL (29% ± 5), compared to E2/DHT group (10 ± 3%). No fast-grow follicles were observed in no FSH and AMH groups. AMH levels at week 3 remained similar in all groups. However, media concentrations of P4 and E2 at week 5 were lower (P < 0.05, undetectable) in no FSH, E2/DHT and AMH groups, compared to CTRL (P4 = 93 ± 10 ng/ml; E2 = 4 ± 1 ng/ml). In the second experiment, FSH depletion diminished follicle survival rate (66 ± 8% in control versus 45 ± 9% in no FSH, P = 0.034). E2 plus DHT (31.5 ± 11%) or DHT alone (69 ± 9%) restored follicle survival rate to the control (FSH) level as expected. Also, E2 plus DHT or DHT alone improved antrum formation rate. However, in the absence of FSH, E2 plus DHT or DHT alone did not support growth, in terms of follicle diameter, or steroid (P4 or E2) production after the antral stage.

LIMITATIONS REASONS FOR CAUTION

This study is limited to in vitro effects of E2, DHT and AMH during the interval from the secondary to small antral stage of macaque follicular development. In addition, the primate follicle pool is heterogeneous and differs between animals; therefore, even though only secondary follicles were selected, follicle growth and developmental outcomes might differ from one animal to another.

WIDER IMPLICATIONS OF THE FINDINGS

This study provides novel information on the possible actions of estrogen and androgen during early follicular development in primates. Our results suggest that sequential exposure of preantral follicles to local factors, e.g. E2 and DHT, followed by gonadotropin once the follicle reaches the antral stage, may better mimic primate folliculogenesis in vivo.

STUDY FUNDING/COMPETING INTEREST(S)

Research reported in this publication was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Center for Translational Research on Reproduction and Infertility 5P50HD071836, and the NIH Primate Centers Program 8P510D011092. There are no conflicts of interest.

Update on oogenesis in vitro

INTRODUCTION

Ovarian tissue is increasingly being collected from cancer patients and cryopreserved for fertility preservation. Alternately to the autologous transplantation, the development of culture systems that support oocyte development from the primordial follicle stage represent a valid strategy to restore fertility. The aim of this study is to review the most recent data regarding oogenesis in vitro and to provide an up-to-date on the contemporary knowledge of follicle growth and development in vitro.

EVIDENCE ACQUISITION

A comprehensive systematic MEDLINE search was performed since February 2018 for English-language reports by using the following terms: "ovary," "animal and human follicle," "in vitro growth and development," "ovarian tissue culture," "fertility preservation," "IVM," "oocyte." Previous published reviews and recent published original articles were preferred in order to meet our study scope.

EVIDENCE SYNTHESIS

Over time, many studies have been conducted with the aim to optimize the characteristics of ovarian tissue culture systems and to better support the three main phases: 1) activation of primordial follicles; 2) isolation and culture of growing preantral follicles; 3) removal from the follicle environment and maturation of oocyte cumulus complexes. While complete oocyte in vitro development has been achieved in mouse, with the production of live offspring, the goal of obtaining oocytes of sufficient quality to support embryo development has not been completely reached into higher mammals despite decades of effort.

CONCLUSIONS

Over the years, many improvements have been made on ovarian tissue cultures with the future purpose that patients will be provided with a greater number of developmentally competent oocytes for fertility preservation.

Anti-Müllerian hormone overexpression restricts preantral ovarian follicle survival

Anti-Müllerian hormone (AMH) is an ovarian regulator that affects folliculogenesis. AMH inhibits the developmental activation of the dormant primordial follicles and the oocyte within. In more mature follicles, AMH reduces granulosa cell sensitivity to follicle-stimulating hormone (FSH). We examined the effects of AMH overexpression on the stages of ovarian folliculogenesis, and the development of embryos, with a transgenic mouse that overexpresses human AMH in central nervous system neurons under the control of the mouse Thy1.2 promoter (Thy1.2-AMHTg mice). These mice are severely sub-fertile, despite relatively normal ovulation rates. The embryos of Thy1.2-AMHTg females exhibited delayed preimplantation development and extensive mid-gestation fetal resorption. Young Thy1.2-AMHTg mouse ovaries exhibited only a slight reduction in the rate of primordial follicle activation but large declines in the number of developing follicles surviving past the primary stage. It was expected that Thy1.2-AMHTg mice would retain more primordial follicles as they aged, but at 5 months, their number was significantly reduced relative to wild-type females. These data indicate that moderate elevations in AMH levels can severely restrict reproductive output and the number of developing follicles in the ovary. This evidence suggests that early antral follicles are a target for AMH signaling, which may regulate early follicle survival.

Acetylcholine and necroptosis are players in follicular development in primates

Acetylcholine (ACh) in the ovary and its actions were linked to survival of human granulosa cells in vitro and improved fertility of rats in vivo. These effects were observed upon experimental blockage of the ACh-degrading enzyme (ACH esterase; ACHE), by Huperzine A. We now studied actions of Huperzine A in a three-dimensional culture of macaque follicles. Because a form of programmed necrotic cell death, necroptosis, was previously identified in human granulosa cells in vitro, we also studied actions of necrostatin-1 (necroptosis inhibitor). Blocking the breakdown of ACh by inhibiting ACHE, or interfering with necroptosis, did not improve the overall follicle survival, but promoted the growth of macaque follicles from the secondary to the small antral stage in vitro, which was correlated with oocyte development. The results from this translational model imply that ovarian function and fertility in primates may be improved by pharmacological interference with ACHE actions and necroptosis.

Imaging the ovary

During each reproductive cycle, the ovary exhibits tissue remodelling and cyclic vasculature changes associated with hormonally regulated folliculogenesis, follicle rupture, luteal formation and regression. However, the relationships among different types of follicles and corpora lutea are unclear, and the role of ovarian vasculature in folliculogenesis and luteal dynamics has not been extensively investigated. Understanding of ovarian physiology and pathophysiology relies upon elucidation of ovarian morphology and architecture. This paper summarizes the literature on traditional approaches to the imaging of ovarian structures and discusses recent advances in ovarian imaging. Traditional in-vivo ultrasound, together with histological and electron microscopic approaches provide detailed views of the ovary at organ, tissue and molecular levels. However, in-vivo imaging is limited to antral and larger follicles whereas histological imaging is mainly two-dimensional in nature. Also discussed are emerging approaches in the use of near-infrared fluorophores to image follicles in live animals to detect preantral follicles as well as visualizing ovarian structures using CLARITY in fixed whole ovaries to elucidate three-dimensional interrelationships among follicles, corpora lutea and ovarian vasculature. Advances in ovarian imaging techniques provide new understanding of ovarian physiology and allow for the development of better tools to diagnose ovarian pathophysiology.

In-vitro regulation of primordial follicle activation: challenges for fertility preservation strategies

Ovarian tissue is increasingly being collected from cancer patients and cryopreserved for fertility preservation. While the only available option to restore fertility is autologous transplantation, this treatment is not appropriate for all patients due to the risk of reintroducing cancer cells and causing disease recurrence. Harnessing the full reproductive potential of this tissue to restore fertility requires the development of culture systems that support oocyte development from the primordial follicle stage. While this has been achieved in the mouse, the goal of obtaining oocytes of sufficient quality to support embryo development has not been reached in higher mammals despite decades of effort. In vivo, primordial follicles gradually exit the resting pool, whereas when primordial follicles are placed into culture, global activation of these follicles occurs. Therefore, the addition of a factor(s) that can regulate primordial follicle activation in vitro may be beneficial to the development of culture systems for ovarian tissue from cancer patients. Several factors have been observed to inhibit follicle activation, including anti-Müllerian hormone, stromal-derived factor 1 and members of the c-Jun-N-terminal kinase pathway. This review summarizes the findings from studies of these factors and discusses their potential integration into ovarian tissue culture strategies for fertility preservation.

Anti-Müllerian hormone in type 2 and gestational diabetes during the second half of pregnancy: relationship with sexual steroid levels and metabolic parameters

Hyperandrogenemia and hyperinsulinemia are observed in women with diabetes during pregnancy. The effect of diabetes on anti-Müllerian hormone (AMH) levels during pregnancy is unclear. The aim of this study was to determine the AMH levels in women with type 2 diabetes (T2D) and gestational diabetes (GD) compared to healthy (C) pregnant women during the second half of gestation. A prospective study of 69 pregnant women with T2D (N: 21), GD (N: 24) and C (N: 24) were followed up during the second half of pregnancy. Clinical assessments and blood samples were collected at 26.7 (25-27.8); 34 (32-34.9) and 37.5 (37-40) weeks of gestation. AMH, sexual steroids, insulin, homeostatic model assessment of insulin resistance, HbA1c levels were measured. AMH levels were similar between T2D, GD and C (p = .07). A decline of AMH levels during the second half of gestation was observed in the three groups (p < .0001). AMH levels were negatively associated with age (p < .001). A positive association between AMH and testosterone (p < .05) was found in all groups. A progressive decline of AMH levels is observed in diabetic and healthy women during the second half of pregnancy. Testosterone levels are an independent factor that influences AMH levels during pregnancy. However, AMH levels are not affected by the presence of diabetes during gestation.

Anti-Müllerian hormone is a survival factor and promotes the growth of rhesus macaque preantral follicles during matrix-free culture

Anti-Müllerian hormone (AMH) plays a key role during ovarian follicular development, with local actions associated with a dynamic secretion profile by growing follicles. While results for AMH effects on antral follicle growth and function are consistent among studies in various species, any effects on preantral follicle development remain controversial. Therefore, experiments were conducted to investigate the direct actions and role of AMH during follicle development at the preantral stage. Macaque-specific short-hairpin RNAs (shRNAs) targeting AMH mRNA were incorporated into adenoviral vectors to decrease AMH gene expression in rhesus macaque follicles. Secondary follicles were isolated from adult macaque ovaries and cultured individually in the ultra-low-attachment dish containing defined medium supplemented with follicle-stimulating hormone and insulin for 5 weeks. Follicles were randomly assigned to treatment groups: (a) control, (b) nontargeting control shRNA-vector, (c) AMH shRNA-vector, (d) AMH shRNA-vector + recombinant human AMH, and (e) recombinant human AMH. Follicle survival and growth were assessed. Culture media were analyzed for steroid hormone and paracrine factor concentrations. For in vivo study, the nontargeting control shRNA-vector and AMH shRNA-vector were injected into macaque ovaries. Ovaries were collected 9 days postinjection for morphology and immunohistochemistry assessment. Decreased AMH expression reduced preantral follicle survival and growth in nonhuman primates. Supplemental AMH treatment in the culture media promoted preantral follicle growth to the small antral stage in vitro with increased steroid hormone and paracrine factor production, as well as oocyte maturation. These data demonstrate that AMH is a critical follicular paracrine/autocrine factor positively impacting preantral follicle survival and growth in primates.

Effect of controlled ovarian hyperstimulation on puberty and estrus in mice offspring

Controlled ovarian hyperstimulation (COH) is widely used for the treatment of infertility, while the long-term effects of COH on the reproductive function in female offspring are currently unknown. Based on the fact that COH could cause high E2 levels in women throughout pregnancy and excess estrogenic exposure during fetal development is harmful to subsequent adult ovarian function, we assumed the hypothesis that COH disrupts reproductive function in female offspring. To test this hypothesis, COH was induced in mice to obtain female offspring by pregnant mare serum gonadotropin (PMSG) and HCG, and then we evaluated pubertal transition, serum levels of E2, anti-Mullerian hormone (AMH), FSH and LH, mRNA expressions of Esr1, Amhr2, Fshr and Lhcgr in ovaries, number of follicles and ovarian histology. We also investigated the apoptosis of follicles by TUNEL; the mRNA expressions of Fas, FasL, Bax, Bcl2, and caspase 3, 8 and 9 by quantitative real-time PCR; and the protein expressions of cleaved-caspase (CASP) 3, 8 and 9 by Western blot. Moreover, we further observed estrous cyclicity in young adult offspring, performed follicle counting and measured the level of AMH in both serum and ovary. COH could induce detrimental pregnancy outcomes, as well as delayed pubertal transition and irregular estrous cycle due to the aberrant growth and maturation of follicles in female offspring. Our novel findings add new evidence to better understand the potential risks of COH on the reproductive function in female offspring, raising the awareness that COH could exert adverse effects on female offspring, rather than just obtain more oocytes for fertilization.