Developmental programming: prenatal testosterone excess disrupts anti-Müllerian hormone expression in preantral and antral follicles

Phenotypic and genetic relationships among anogenital distance, anti-Müllerian hormone, and in vitro embryo production in Gyr dairy cattle

Anti-Müllerian hormone (AMH) concentration and number of recovered oocytes (ROOC) are phenotypic parameters associated with in vitro embryo production (IVEP). More recently, anogenital distance (AGD) has been proposed as a proxy for fertility in dairy cattle that is easy to collect at a low cost. The aim of this study was to characterize the AGD and its phenotypic and genetic associations with AMH and IVEP in Bos indicus Gyr dairy cattle. The hypothesis was that the number of ROOC, in vitro-produced embryos, and AMH concentration would increase as the AGD decreases. From July to December 2021, a single morphometrical measurement of AGD was collected in 552 donors from 6 herds in Brazil. A subset of donors had AMH assayed on the same day. Only ovum pick-up events that occurred up to 12 mo preceding and 7 mo succeeding the AGD measurement were used to assess the association between AGD, AMH, and IVEP. Thus, 472 donors (1,551 ovum pick-up events and 140 donors with AMH) were considered in the analysis. A raw average was calculated for each individual donor's ROOC, viable oocytes, total produced embryos, viability rate, and embryo rate (defined as total produced embryos/viable oocytes). Comparisons were conducted within the age categories of 3 to <6 yr or 6 to <10 yr. Phenotypic associations were performed in SAS software (SAS Institute Inc., Cary, NC). Genetic correlations were estimated using the BLUPF90 family of programs. The AGD (128.7 mm ± 14; mean ± standard deviation) had a normal distribution and was highly variable (83 to 172 mm) among the Gyr population. Our experimental hypothesis was partially supported by a phenotypic association of a greater number of total produced embryos (R2 = 0.023) as AGD decreased. Our results failed to support an increase in AMH concentration along with a decrease in AGD. In addition, positive and low genetic correlations were observed between AGD and viable oocytes (r = 0.08), and embryo rate (r = 0.20). A greater number of viable oocytes and embryos were observed in donors in the high compared with intermediate and low ROOC categories within both age categories. The age interval of 3 to <6 yr showed a greater number of recovered and viable oocytes for the high AMH compared with the low category, but no differences were observed among the AGD categories. In summary, for the Gyr breed, AGD was phenotypically inversely associated with a quantity-related parameter, such as the total number of produced embryos. In contrast, AGD showed a low genetic correlation with qualitative-related outcomes such as viable oocytes and embryo rate. Further studies should be performed to validate these retrospective analyses and to better understand the association between AGD and IVEP.

Anti-Müllerian hormone beyond an ovarian reserve marker: the relationship with the physiology and pathology in the life-long follicle development

Anti-Müllerian hormone (AMH), an indirect indicator of the number of remaining follicles, is clinically used as a test for ovarian reserve. Typically, a decline suggests a decrease in the number of remaining follicles in relation to ovarian toxicity caused by interventions, which may implicate fertility. In contrast, serum AMH levels are elevated in patients with polycystic ovary syndrome. AMH is produced primarily in the granulosa cells of the preantral and small antral follicles. Thus it varies in association with folliculogenesis and the establishment and shrinking of the follicle cohort. Ovarian activity during the female half-life, from the embryonic period to menopause, is based on folliculogenesis and maintenance of the follicle cohort, which is influenced by developmental processes, life events, and interventions. AMH trends over a woman's lifetime are associated with in vivo follicular cohort transitions that cannot be observed directly.

Review: The ovarian follicular reserve - implications for fertility in ruminants

Ruminants are born with a finite number of healthy ovarian follicles and oocytes (ovarian reserve) and germ cell proliferation in the developing foetal gonad predominantly occurs during early gestation. Two markers have been established to reliably estimate the size of the ovarian reserve in cattle: the number of antral follicles ≤3 mm in diameter recruited per follicular wave (Antral Follicle Count, AFC) and peripheral concentrations of the Anti-Müllerian hormone (AMH). Studies that used one or both indicators show that the size of ovarian reserve varies greatly among age-matched individuals, but is highly repeatable in the same animal. Conditions during prenatal life are likely among the causes of such variation in the ovarian reserve. In addition, the size of the ovarian reserve is a moderately heritable trait in cattle. The association between ovarian reserve and fertility is controversial. Several studies indicate that cattle with a low ovarian reserve have phenotypic characteristics that are associated with suboptimal fertility. On the contrary, the presence and absence of a positive association between AFC and/or AMH and fertility measures (i.e. no. on services/conception, pregnancy rates, pregnancy loss) have been equally reported in cattle. In conclusion, the size of the ovarian reserve in the progeny can be enhanced by improving management of the dam from preconception to early gestation and also through genetic selection. However, although the ovarian reserve may be among the determinants of reproductive success in ruminants, the use of AFC/AMH as reliable predictors of fertility is yet to be established. Furthermore, the possibility that there is a complex interaction of AFC, AMH and reproduction has yet to be fully characterised and exploited to improve fertility in cattle.

A meta-analysis of mRNA expression profiling studies in sheep with different FecB genotypes

The FecB mutation in the sheep BMPRIB is strongly correlated with high ovulation traits but its mechanism remains unclear. This study explored differentially expressed genes (DEGs) and their associated molecular mechanisms that may be involved in FecB mutation-induced high ovulation from the perspective of the hypothalamic-pituitary-gonadal (HPG) axis by conducting a systematic review and meta-analysis. The PubMed, EMBASE, CNKI, WanFang, and CBM databases were searched for eligible articles published before August 2022, focusing on mRNA sequencing of different tissues in the HPG axis in sheep with different FecB genotypes. A total of 6555 DEGs were identified from the analysis of six published articles and experimental results from our laboratory. The DEGs were screened by vote-counting rank and robust rank aggregation. Among these, in the follicular phase, FKBP5, CDCA7 and CRABP1 were upregulated in the hypothalamus. INSM2 was upregulated, while LDB3 was downregulated in the pituitary. CLU, SERPINA14, PENK, INHA and STAR were upregulated, while FERMT2 and NPY1R were downregulated in the ovary. On the HPG axis, TAC1 was upregulated and NPNT was downregulated. Many DEGs were found in sheep with different FecB genotypes. The genes FKBP5, CDCA7, CRABP1, INSM2, LDB3, CLU, SERPINA14, PENK, INHA, STAR, FERMT2, NPY1R, TAC1 and NPNT, may be associated with FecB mutation-induced high ovulation in different tissues. These candidate genes will further improve the mechanism of multiple fertility traits induced by the FecB mutation from the perspective of the HPG axis.

Anti-Müllerian Hormone in Female Reproduction

Anti-Müllerian hormone (AMH), also called Müllerian inhibiting substance, was shown to be synthesized by the ovary in the 1980s. This article reviews the main findings of the past 20 years on the regulation of the expression of AMH and its specific receptor AMHR2 by granulosa cells, the mechanism of action of AMH, the different roles it plays in the reproductive organs, its clinical utility, and its involvement in the principal pathological conditions affecting women. The findings in respect of regulation tell us that AMH and AMHR2 expression is mainly regulated by bone morphogenetic proteins, gonadotropins, and estrogens. It has now been established that AMH regulates the different steps of folliculogenesis and that it has neuroendocrine effects. On the other hand, the importance of serum AMH as a reliable marker of ovarian reserve and as a useful tool in the prediction of the polycystic ovary syndrome (PCOS) and primary ovarian failure has also been acknowledged. Last but not least, a large body of evidence points to the involvement of AMH in the pathogenesis of PCOS.

Leukaemia inhibitory factor modulates the differentiation of granulosa cells during sheep in vitro preantral to antral follicle development and improves oocyte meiotic competence

In vitro follicle development from cryopreserved ovarian tissue could become an invaluable assisted reproduction technology for women with early ovarian failure. The challenge lies in producing, from small follicles present in the ovarian cortex, high-quality mature oocytes able to sustain embryo development. In vivo, an optimal combination of hormones and other factors coordinates the development of follicles and their enclosed oocyte. We have investigated the effect of the leukaemia inhibitory factor (LIF) cytokine, alone or in combination with FSH, on sheep in vitro follicle development from the preantral stage onwards. LIF did not alter follicle growth or antrum formation, but it modulated the differentiation of granulosa cells, as revealed by decreased production of anti-Müllerian hormone and abolished FSH-induced stimulation of oestradiol secretion. This modulatory role was also reflected in the abundance of mRNA from 35 genes, analysed by reverse-transcription coupled to microfluidic quantitative PCR. LIF stimulated or at least maintained the expression of genes involved in the dialogue between the oocyte and granulosa cells, through gap junctions (GJA4 encoding connexin 37) or paracrine signalling (Bone morphogenetic protein 15, KIT ligand and their receptors). Finally, the presence of both LIF and FSH during follicle growth strongly improved oocyte meiotic competence: most oocytes (56%) underwent subsequent nuclear maturation, a significant increase compared with their counterparts from follicles of similar size (550-900 µm) cultured with FSH only (28%) or developed in vivo (9%). Their ability to sustain embryo development remains to be evaluated. Combined supplementation with FSH and LIF certainly merits investigation with human follicles.

Elevated Anti-Müllerian Hormone Levels in Newborns of Women with Polycystic Ovary Syndrome: a Systematic Review and Meta-analysis Based on Observational Studies

We performed this updated systematic review and meta-analysis to evaluate anti-Müllerian hormone levels (AMH) in newborns of mothers with polycystic ovary syndrome (PCOS) compared with healthy controls. A search of the literature was conducted in the PubMed, MEDLINE, EMBASE, Cochrane Library, CBM, CNKI, WANFANG, and VIP for articles to assess AMH levels in offspring of PCOS and non-PCOS mothers irrespective of language. These databases were searched from their inception to December 7, 2020. The quality of studies was assessed using the Newcastle-Ottawa Scale (NOS) scoring system. Standardized mean differences (SMDs) with 95% confidence intervals (CIs) were adopted to calculate the overall estimates with random-effects models. A total of 6 studies with 846 participants were included. The pooled analysis found an increased AMH level in the umbilical cord blood in newborns of PCOS mothers (SMD =0.62, 95% CI [0.28, 0.95]). Subgroup analyses revealed an elevation of AMH concentrations in female neonates, neonates born to American and Asian PCOS mothers. In addition, higher AMH levels were also found in studies diagnosed by the National Institute of Health (NIH) criteria, maternal clinical/biochemical hyperandrogenism, or maternal body mass index (BMI) >30 kg/m². Meta-regression analysis suggested that diagnostic criterion contributed mostly to the high heterogeneity. We demonstrated that AMH levels in neonates born to PCOS mothers were essentially higher, which indicates that AMH may act as an enigmatic role in the pathogenesis of PCOS which inhibits folliculogenesis in the fetal stage.

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.

Plasma anti-Müllerian hormone concentration as a predictive endocrine marker for selection of donor lambs to improve success in juvenile in vitro embryo transfer programs

The use of juvenile invitro embryo transfer (JIVET) is limited by variation between prepubertal lambs in ovarian response to exogenous gonadotrophins. In cattle, anti-Müllerian hormone (AMH) is a predictive endocrine marker of antral follicle count. In this study we measured plasma AMH concentrations in lambs at 3 and 5 weeks of age and determined associations between AMH concentrations and ovarian response to gonadotrophins and invitro blastocyst production at 6-8 weeks of age in a JIVET program. At 5 weeks, AMH (n=38) was positively correlated with surface antral follicle count (r=0.87, P<0.001), blastocysts produced (r=0.92, P<0.001) and blastocysts produced as a proportion of oocytes collected (r=0.44, P<0.01) or cleaved (r=0.43, P<0.01). Similar associations were observed between AMH at 3 weeks (n=30) and follicle number (r=0.70, P<0.05) and blastocysts produced (r=0.87, P<0.05). Lambs with high (>2.2ngmL-1) compared with medium (0.4-2.2ngmL-1) and low (<0.4ngmL-1) AMH at 5 weeks had more antral follicles (mean (±s.e.m.) 118.7±13.9 vs 68.2±8.1 and 30.4±12.3 respectively; P<0.05) and more blastocysts produced (mean (±s.e.m.) 54.9±6.9 vs 18.9±4.0 and 7.5±6.1 respectively; P<0.05). These results suggest that AMH concentration at 5 weeks of age can be used to select donor lambs which enhance the success of JIVET programs.

Developmental Programming: Sheep Granulosa and Theca Cell-Specific Transcriptional Regulation by Prenatal Testosterone

Prenatal testosterone (T)-treated sheep, similar to polycystic ovarian syndrome women, manifest reduced cyclicity, functional hyperandrogenism, and polycystic ovary (PCO) morphology. The PCO morphology results from increased follicular recruitment and persistence of antral follicles, a consequence of reduced follicular growth and atresia, and is driven by cell-specific gene expression changes that are poorly understood. Therefore, using RNA sequencing, cell-specific transcriptional changes were assessed in laser capture microdissection isolated antral follicular granulosa and theca cells from age 21 months control and prenatal T-treated (100 mg intramuscular twice weekly from gestational day 30 to 90; term: 147 days) sheep. In controls, 3494 genes were differentially expressed between cell types with cell signaling, proliferation, extracellular matrix, immune, and tissue development genes enriched in theca; and mitochondrial, chromosomal, RNA, fatty acid, and cell cycle process genes enriched in granulosa cells. Prenatal T treatment 1) increased gene expression of transforming growth factor β receptor 1 and exosome component 9, and decreased BCL6 corepressor like 1, BCL9 like, and MAPK interacting serine/threonine kinase 2 in both cells, 2) induced differential expression of 92 genes that included increased mitochondrial, ribosome biogenesis, ribonucleoprotein, and ubiquitin, and decreased cell development and extracellular matrix-related pathways in granulosa cells, and 3) induced differential expression of 56 genes that included increased noncoding RNA processing, ribosome biogenesis, and mitochondrial matrix, and decreased transcription factor pathways in theca cells. These data indicate that follicular function is affected by genes involved in transforming growth factor signaling, extracellular matrix, mitochondria, epigenetics, and apoptosis both in a common as well as a cell-specific manner and suggest possible mechanistic pathways for prenatal T treatment-induced PCO morphology in sheep.

Animal Models to Understand the Etiology and Pathophysiology of Polycystic Ovary Syndrome

More than 1 out of 10 women worldwide are diagnosed with polycystic ovary syndrome (PCOS), the leading cause of female reproductive and metabolic dysfunction. Despite its high prevalence, PCOS and its accompanying morbidities are likely underdiagnosed, averaging > 2 years and 3 physicians before women are diagnosed. Although it has been intensively researched, the underlying cause(s) of PCOS have yet to be defined. In order to understand PCOS pathophysiology, its developmental origins, and how to predict and prevent PCOS onset, there is an urgent need for safe and effective markers and treatments. In this review, we detail which animal models are more suitable for contributing to our understanding of the etiology and pathophysiology of PCOS. We summarize and highlight advantages and limitations of hormonal or genetic manipulation of animal models, as well as of naturally occurring PCOS-like females.

Anti-Mullerian hormone and its relationship to ovulation response and fertility in timed AI Bos indicus heifers

This study evaluated the association between plasma anti-Mullerian hormone (AMH) concentration and fertility in Nelore (Bos indicus) heifers submitted to timed artificial insemination (TAI). At the onset of the synchronization protocol, heifers (n = 289) received a subcutaneous P4 ear implant (3 mg) and 2 mg of oestradiol benzoate. Eight days later, the P4 implant was removed and 0.5 mg of oestradiol cypionate, prostaglandin (0.265 mg, i.m.) and equine chorionic gonadotropin (300 UI, i.m.) was administered, and TAI was performed 48 hr after ear implant removal. Ovarian ultrasound evaluations were performed to measure number of ovarian follicles, dominant follicle size and ovulation response. Pregnancy diagnosis was performed by ultrasound 30 days after AI. Heifers with greater circulating AMH had more antral follicles, a smaller dominant follicle near timed ovulation and lower ovulation response to the timed AI protocol compared to heifers with lower circulating AMH. Although AMH and pregnancy outcome had a quadratic-shaped pattern, AMH was not significantly associated with fertility. In conclusion, heifers with lower AMH had larger follicles towards the end of the synchronization protocol and greater ovulation responses, whereas greater circulating AMH was unrelated to conception success.

Developmental Programming: Prenatal Testosterone Excess on Ovarian SF1/DAX1/FOXO3

Prenatal testosterone (T) excess, partly via androgenic programming, enhances follicular recruitment/persistence in sheep as in women with polycystic ovarian syndrome (PCOS). Decreased anti-Mullerian hormone (AMH) in early growing and increased AMH in antral follicles may underlie enhanced recruitment and persistence, respectively. Changes in AMH may be mediated by steroidogenic factor 1 (SF1), an enhancer of AMH, and dosage-sensitive sex reversal, adrenal hypoplasia critical region, on chromosome X, gene 1 (DAX1), that antagonizes SF1. Another mediator could be forkhead box 03 (FOXO3) which regulates follicular recruitment/atresia. To test if androgen-programmed changes in SF1, DAX1, and FOXO3 proteins contribute to follicular defects in prenatal T-treated sheep, ovaries from control, prenatal T-, and dihydrotestosterone (DHT)-treated (days 30-90 of gestation) animals at fetal day (FD) 90, FD140, and 1 and 2 years-of-age were studied. Prenatal T increased DAX1 in granulosa cells of primordial through large preantral and theca cells of large preantral follicles at FD140 and increased SF1 in the granulosa cells of preantral and antral and theca cells of large preantral follicle at 2 years-of-age. Prenatal T increased FOXO3 only in theca cells of preantral (FD140) and antral (2 years-of-age) follicles. Prenatal DHT increased DAX1 in granulosa cells from small preantral follicles at FD140 while increasing SF1 in granulosa cells from antral follicles at 1 year-of-age. These age-dependent changes in DAX1/SF1 partly via androgen-programming are consistent with changes in AMH and may contribute to the enhanced follicular recruitment/persistence, and multifollicular phenotype of prenatal T-treated females and may be of translational relevance to PCOS.

AMH: Could It Be Used as A Biomarker for Fertility and Superovulation in Domestic Animals?

Anti-Müllerian hormone (AMH) is a reliable and easily detectable reproductive marker for the fertility competence of many farm animal species. AMH is also a good predictor of superovulation in cattle, sheep, and mares. In this review, we have summarized the recent findings related to AMH and its predictive reliability related to fertility and superovulation in domestic animals, especially in cattle. We focused on: (1) the dynamics of AMH level from infancy to prepubescence as well as during puberty and adulthood; (2) AMH as a predictor of fertility; (3) the association between antral follicle count (AFC) and plasma AMH level; (4) AMH as a predictor of superovulation; and (5) factors affecting AMH levels in domestic animals, especially cattle. Many factors affect the circulatory levels of AMH when considering the plasma, like nutrition, activity of granulosa cells, disease state and endocrine disruptions during fetal life. Briefly, we concluded that AMH concentrations are static within individuals, and collection of a single dose of blood has become more popular in the field of assisted reproductive technologies (ART). It may act as a potential predictor of fertility, superovulation, and ovarian disorders in domestic animals. However, due to the limited research in domestic animals, this potential of AMH remains underutilized.

Developmental Programming: Contribution of Epigenetic Enzymes to Antral Follicular Defects in the Sheep Model of PCOS

Prenatal testosterone (T)-treated sheep, similar to women with polycystic ovary syndrome (PCOS), manifest oligo-/anovulation, hyperandrogenism, and polyfollicular ovary. The polyfollicular ovarian morphology, a result of persistence of antral follicles, arises, in part, by transcriptional changes in key mediators of follicular development that, in turn, are driven by epigenetic mechanisms. We hypothesized that prenatal T excess induces, in a cell-specific manner, transcriptional changes in key mediators of follicular development associated with relevant changes in epigenetic machinery. Expression levels of key mediators of follicular development, DNA methyltransferases (DNMTs), and histone de-/methylases and de-/acetylases were determined in laser-capture microdissection-isolated antral follicular granulosa and theca and ovarian stromal cells from 21 months of age control and prenatal T-treated sheep (100 mg IM twice weekly from gestational day 30 to 90; term: 147 days). Changes in histone methylation were determined by immunofluorescence. Prenatal T treatment induced the following: (i) cell-specific changes in gene expression of key mediators of follicular development and steroidogenesis; (ii) granulosa, theca, and stromal cell-specific changes in DNMTs and histone de-/methylases and deacetylases, and (iii) increases in histone 3 trimethylation at lysine 9 in granulosa and histone 3 dimethylation at lysine 4 in theca cells. The pattern of histone methylation was consistent with the expression profile of histone de-/methylases in the respective cells. These findings suggest that changes in expression of key genes involved in the development of the polyfollicular phenotype in prenatal T-treated sheep are mediated, at least in part, by cell-specific changes in epigenetic-modifying enzymes.

Inferior fertility and higher concentrations of anti-Müllerian hormone in dairy cows with longer anogenital distance

Anogenital distance (AGD), which is an indicator of prenatal androgen exposure, has been reported to have high variability and negative association with fertility in dairy cows. Prenatal exposure to androgens could influence the development of primordial follicles and size of ovarian reserve, which is related to reproduction. However, the relationship between AGD and size of ovarian reserve has not been studied. Therefore, the present study was conducted to determine the association between AGD and circulating anti-Müllerian hormone (AMH), as an indirect marker of ovarian reserve, and to evaluate serum AMH concentration and reproductive performance in dairy cows with short and long AGD. Anogenital distance was measured 28 to 32 d postpartum, and based on the median of AGD, cows were divided into 2 subsets including short (n = 43) and long (n = 43) AGD groups. Afterward, serum AMH was evaluated on the day of estrus in cows that were estrus-synchronized. Furthermore, reproductive data of dairy cows during the previous lactation period were collected from the herd database. Concentrations of serum AMH tended to be positively associated with length of AGD, and there was a tendency for higher serum AMH concentrations in the long (634.89 ± 74.52 pg/mL) than short (451.39 ± 45.92 pg/mL) AGD group (0.05 <P ≤ 0.10). There was a tendency for more days to first service, lower first service conception rate, and higher proportion of repeat breeders in long (99.95 ± 5.34 d, 30.23% and 32.56%, respectively) than short (89.07 ± 4.97 d, 48.84% and 16.28%, respectively) AGD cows (0.05 <P ≤ 0.10). Services per conception did not differ between short (2.30 ± 0.27) and long (2.93 ± 0.29) AGD cows (P > 0.05). Calving to conception interval was prolonged in long (194.30 ± 17.12 d) than short (147.14 ± 13.11 d) AGD cows (P ≤ 0.05). In conclusion, the present study revealed elevated serum AMH concentrations and poor reproductive performance in cows with longer AGD compared with cows with shorter AGD.

DNA methylation in the pathogenesis of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the leading endocrine and metabolic disorder in premenopausal women characterized by hyperandrogenism and abnormal development of ovarian follicles. To date, the PCOS etiology remains unclear and has been related to insulin resistance, obesity, type 2 diabetes mellitus, cardiovascular disease and infertility, among other morbidities. Substantial evidence illustrates the impact of genetic, intrauterine and environmental factors on the PCOS etiology. Lately, epigenetic factors have garnered considerable attention in the pathogenesis of PCOS considering that changes in the content of DNA methylation, histone acetylation and noncoding RNAs have been reported in various tissues of women with this disease. DNA methylation is changed in the peripheral and umbilical cord blood, as well as in ovarian and adipose tissue of women with PCOS, suggesting the involvement of this epigenetic modification in the pathogenesis of the disease. Perhaps, these defects in DNA methylation promote the deregulation of genes involved in inflammation, hormone synthesis and signaling and glucose and lipid metabolism. Research on the role of DNA methylation in the pathogenesis of PCOS is just beginning, and several issues await investigation. This review aims to provide an overview of current research focused on DNA methylation and PCOS, as well as discuss the perspectives regarding this topic.

Anti-Müllerian hormone and progesterone levels in human follicular fluid are predictors of embryonic development

BACKGROUND

Human follicular fluid is an intricate biological fluid contributing to the developing oocyte microenvironment. Accumulating evidence suggests that sex hormones present in follicular fluid (FF) may play an important role in regulating oocyte developmental potential. The aim of this study was to determine if anti-Müllerian hormone (AMH) and progesterone (P4) levels in FF are correlated with oocyte quality as defined by subsequent embryonic development.

METHODS

This was a prospective cohort study of 88 women undergoing IVF/ICSI at a university associated fertility clinic. Follicular fluid was collected from the first follicle aspirated at the time of oocyte retrieval. The corresponding oocyte was individually cultured in order to track its developmental outcome. FF-AMH and P4 concentrations from follicles where the oocyte fertilised normally and developed into a blastocyst on day 5 (Group 1: BLAST, n = 23) were compared with FF from follicles where the oocyte fertilised normally but failed to reach blastocyst stage by day 5 (Group 2: FERT, n = 19). No significant differences were observed between the two groups in terms of maternal age, body mass index, previous live births, previous pregnancy loss, number of antral follicles, number of oocytes recovered, IVF:ICSI ratio or percentage of recovered oocytes that fertilised.

RESULTS

FF-AMH and P4 levels were significantly increased in Group 1: BLAST compared to Group 2: FERT (P = 0.007 and P = 0.013 respectively). Twenty-one FF samples had an AMH level > 15 pmol/L, of which 17 related to oocytes that progressed to blastocyst stage, providing a positive prediction value (PPV) of 76.96%. Eleven FF samples had a P4 level > 60 mg/ml, of which 10 progressed to blastocyst stage, providing a PPV of 90.99%. Six samples had an AMH level > 15 pmol/L and a P4 level > 60 mg/ml, of which 100% progressed to blastocyst stage, providing a PPV of 96.83%.

CONCLUSIONS

FF-AMH and P4 levels from individual follicles can accurately predetermine subsequent embryonic development. Combining follicular fluid analysis with routine morphological assessment, could allow for a more accurate and sensitive method of determining embryonic developmental competence.

Ovarian and Extra-Ovarian Mediators in the Development of Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a heterogeneous endocrine disorder affecting women of reproductive age. The origin of PCOS is still not clear and appears to be a function of gene x environment interactions. This review addresses the current knowledge of the genetic and developmental contributions to the etiology of PCOS, the ovarian and extra-ovarian mediators of PCOS and the gaps and key challenges that need to be addressed in the diagnosis, treatment and prevention of PCOS.

Developmental Programming of Ovarian Functions and Dysfunctions

The pathophysiological mechanisms underlying the origin of several ovarian pathologies remain unclear. In addition to the genetic basis, developmental insults are gaining attention as a basis for the origin of these pathologies. Such early insults include maternal over or under nutrition, stress, and exposure to environmental chemicals. This chapter reviews the development and physiological function of the ovary, the known ovarian pathologies, the developmental check points of ovarian differentiation impacted by developmental insults, the role played by steroidal and metabolic factors as mediaries, the epigenetic mechanisms via which these mediaries induce their effects, and the knowledge gaps for targeting future studies to ultimately aid in the development of improved treatments.

Is foetal hyperexposure to androgens a cause of PCOS?

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy affecting reproductive-aged women. The pathophysiology of this syndrome is still not completely understood but recent evidence suggests that the intra-uterine environment may be a key factor in the pathogenesis of PCOS, in particular, hyperexposure of the foetus to androgens. High concentrations of maternal serum testosterone during pregnancy have been shown to influence behaviour during childhood, the prevalence of autism disorders and anti-Mullerian hormone (AMH) concentrations in adolescence. They are also thought to re-programme the female reproductive axis to induce the features of PCOS in later life: oligo/anovulation, polycystic ovaries, hyperandrogenism and insulin resistance (IR). Support for this developmental theory for the aetiology of PCOS is gathering momentum, following results from first animal studies and now human data, which lend credence to many aspects of this hypothesis.

OBJECTIVE AND RATIONALE

In this review the recent available evidence is presented to support the hypothesis that hyperandrogenic changes in the intra-uterine environment could play a major part in the aetiological basis of PCOS.

SEARCH METHODS

An extensive PubMED and MEDline database search was conducted. Relevant studies were identified using a combination of search terms: 'polycystic ovary syndrome', 'PCOS', 'aetiology', 'anti-Mullerian hormone', 'AMH', 'pathogenesis', 'kisspeptin', 'hyperandrogenism', 'insulin resistance', 'metabolic factors', 'placenta', 'developmental hypothesis', 'genetic and epigenetic origins'.

OUTCOMES

A total of 82 studies were finally included in this review. There is robust evidence that a hyperandrogenic intra-uterine environment 'programmes' the genes concerned with ovarian steroidogenesis, insulin metabolism, gonadotrophin secretion and ovarian follicle development resulting in the development of PCOS in adult life.

WIDER IMPLICATIONS

Once the evidence supporting this hypothesis has been expanded by additional studies, the door would be open to find innovative treatments and preventative measures for this very prevalent condition. Such measures could considerably ease the human and economic burden that PCOS creates.

Androgen Stimulates Growth of Mouse Preantral Follicles In Vitro: Interaction With Follicle-Stimulating Hormone and With Growth Factors of the TGFβ Superfamily

Androgens are essential for the normal function of mature antral follicles but also have a role in the early stages of follicle development. Polycystic ovary syndrome (PCOS), the most common cause of anovulatory infertility, is characterized by androgen excess and aberrant follicle development that includes accelerated early follicle growth. We have examined the effects of testosterone and dihydrotestosterone (DHT) on development of isolated mouse preantral follicles in culture with the specific aim of investigating interaction with follicle-stimulating hormone (FSH), the steroidogenic pathway, and growth factors of the TGFβ superfamily that are known to have a role in early follicle development. Both testosterone and DHT stimulated follicle growth and augmented FSH-induced growth and increased the incidence of antrum formation among the granulosa cell layers of these preantral follicles after 72 hours in culture. Effects of both androgens were reversed by the androgen receptor antagonist flutamide. FSH receptor expression was increased in response to both testosterone and DHT, as was that of Star, whereas Cyp11a1 was down-regulated. The key androgen-induced changes in the TGFβ signaling pathway were down-regulation of Amh, Bmp15, and their receptors. Inhibition of Alk6 (Bmpr1b), a putative partner for Amhr2 and Bmpr2, by dorsomorphin resulted in augmentation of androgen-stimulated growth and modification of androgen-induced gene expression. Our findings point to varied effects of androgen on preantral follicle growth and function, including interaction with FSH-activated growth and steroidogenesis, and, importantly, implicate the intrafollicular TGFβ system as a key mediator of androgen action. These findings provide insight into abnormal early follicle development in PCOS.

Anti-Müllerian Hormone (AMH) and fertility management in agricultural species

A reliable, easy to assess marker for fertility in agricultural species would be highly desirable and Anti-Müllerian Hormone (AMH) is a promising candidate. This review summarizes recent findings concerning AMH and its role in fertility management, mainly in cattle. It focuses on (1) alterations in circulating AMH concentrations from birth to puberty and during estrous cycles; (2) correlation of circulating AMH concentrations with ovarian follicle numbers and ovarian reserve; (3) factors that impact circulating AMH concentrations; (4) use of AMH as a predictor of fertility. Circulating AMH concentrations can be easily and reliably measured with a single blood sample in adult cattle because AMH varies minimally during the estrous cycle and is repeatable across multiple cycles. Circulating AMH concentrations are positively associated with several measures of fertility. Dairy heifers with low compared with higher AMH concentrations subsequently had lower pregnancy rates, higher probability of being culled after birth of their first calf and shorter herd longevity. Also, AMH is predictive of response to superovulation in cattle and sheep. Several factors contribute to the variability in AMH concentrations among individuals; for example, beef cattle have higher AMH than dairy cattle. Nutritional imbalances, disease and endocrine disruptors during fetal life may negatively program the size of the ovarian reserve and consequently serum AMH concentrations and potential fertility in adulthood. We conclude that AMH may be a predictor of fertility and herd longevity in cattle, whereas in sheep and other farm species, the potential association between AMH and reproductive performance remains largely unexplored.Free Italian abstract: An Italian translation of this abstract is freely available at http://www.reproduction-online.org/content/154/1/R1/suppl/DC1.

Developmental Programming: Gestational Exposure to Excess Testosterone Alters Expression of Ovarian Matrix Metalloproteases and Their Target Proteins

Prenatal testosterone (T)-treated sheep, similar to women with polycystic ovary syndrome (PCOS), manifests reproductive defects that include multifollicular ovarian phenotype. Women with PCOS manifest increased ovarian matrix metalloproteinases (MMPs) activity. We tested the hypothesis that gestational T excess in sheep would alter ovarian expression of MMPs, tissue inhibitors of MMP (TIMP) and their target proteins laminin B (LAMB), collagen, tumor necrosis factor alpha (TNF), and connexin 43 (GJA1) consistent with increased MMP activity and that these changes are developmentally regulated. The ovarian content of these proteins was quantified by immunohistochemistry in fetal day 90, 140, and adult (21 months of age) ovaries. Prenatal T excess lowered GJA1 protein content in stroma and granulosa cells of primary follicles from fetal day 90 ovaries and decreased stromal MMP9, TIMP1, and LAMB in fetal day 140 ovaries. In the adult, prenatal T-treatment (1) increased MMP9 in theca cells of large preantral follicles and stroma, TNF in granulosa cells of small and large preantral follicles and theca cells of large preantral and antral follicles, and GJA1 in stroma, theca cells of large preantral follicles, and granulosa cells of antral follicles and (2) reduced TIMP1 in stroma, theca cells of large preantral and antral follicles, LAMB in stroma and small prenatral follicles, and collagen content in stroma and around antral follicles. These findings suggest a net increase in MMP activity and its target proteins TNF and GJA1 in prenatal T-treated adult but not in fetal ovaries and their potential involvement in the development of multifollicular morphology.

The Pathogenesis of Polycystic Ovary Syndrome (PCOS): The Hypothesis of PCOS as Functional Ovarian Hyperandrogenism Revisited

Polycystic ovary syndrome (PCOS) was hypothesized to result from functional ovarian hyperandrogenism (FOH) due to dysregulation of androgen secretion in 1989-1995. Subsequent studies have supported and amplified this hypothesis. When defined as otherwise unexplained hyperandrogenic oligoanovulation, two-thirds of PCOS cases have functionally typical FOH, characterized by 17-hydroxyprogesterone hyperresponsiveness to gonadotropin stimulation. Two-thirds of the remaining PCOS have FOH detectable by testosterone elevation after suppression of adrenal androgen production. About 3% of PCOS have a related isolated functional adrenal hyperandrogenism. The remaining PCOS cases are mild and lack evidence of steroid secretory abnormalities; most of these are obese, which we postulate to account for their atypical PCOS. Approximately half of normal women with polycystic ovarian morphology (PCOM) have subclinical FOH-related steroidogenic defects. Theca cells from polycystic ovaries of classic PCOS patients in long-term culture have an intrinsic steroidogenic dysregulation that can account for the steroidogenic abnormalities typical of FOH. These cells overexpress most steroidogenic enzymes, particularly cytochrome P450c17. Overexpression of a protein identified by genome-wide association screening, differentially expressed in normal and neoplastic development 1A.V2, in normal theca cells has reproduced this PCOS phenotype in vitro. A metabolic syndrome of obesity-related and/or intrinsic insulin resistance occurs in about half of PCOS patients, and the compensatory hyperinsulinism has tissue-selective effects, which include aggravation of hyperandrogenism. PCOS seems to arise as a complex trait that results from the interaction of diverse genetic and environmental factors. Heritable factors include PCOM, hyperandrogenemia, insulin resistance, and insulin secretory defects. Environmental factors include prenatal androgen exposure and poor fetal growth, whereas acquired obesity is a major postnatal factor. The variety of pathways involved and lack of a common thread attests to the multifactorial nature and heterogeneity of the syndrome. Further research into the fundamental basis of the disorder will be necessary to optimally correct androgen levels, ovulation, and metabolic homeostasis.

Developmental programming: rescuing disruptions in preovulatory follicle growth and steroidogenesis from prenatal testosterone disruption

BACKGROUND

Prenatal testosterone (T) excess from days 30-90 of gestation disrupts gonadotropin surge and ovarian follicular dynamics and induces insulin resistance and functional hyperandrogenism in sheep. T treatment from days 60-90 of gestation produces a milder phenotype, albeit with reduced fecundity. Using this milder phenotype, the aim of this study was to understand the relative postnatal contributions of androgen and insulin in mediating the prenatal T induced disruptions in ovarian follicular dynamics.

METHODS

Four experimental groups were generated: 1) control (vehicle treatment), 2) prenatal T-treated (100 mg i.m. administration of T propionate twice weekly from days 60-90 of gestation), 3) prenatal T plus postnatal anti-androgen treated (daily oral dose of 15 mg/kg/day of flutamide beginning at 8 weeks of age) and 4) prenatal T and postnatal insulin sensitizer-treated (daily oral dose of 8 mg/day rosiglitazone beginning at 8 weeks of age). Follicular response to a controlled ovarian stimulation protocol was tested during their third breeding season. Main outcome measures included the determination of number and size of ovarian follicles and intrafollicular concentrations of steroids.

RESULTS

At the end of the controlled ovarian stimulation, the number of follicles approaching ovulatory size (≥6 mm) were ~35 % lower in prenatal T-treated (6.5 ± 1.8) compared to controls (9.8 ± 2.0). Postnatal anti-androgen (10.3 ± 1.9), but not insulin sensitizer (5.0 ± 0.9), treatment prevented this decrease. Preovulatory sized follicles in the T group had lower intrafollicular T, androstenedione, and progesterone compared to that of the control group. Intrafollicular steroid disruption was partially reversed solely by postnatal insulin sensitizer treatment.

CONCLUSIONS

These results demonstrate that the final preovulatory follicular growth and intrafollicular steroid milieu is impaired in prenatal T-treated females. The findings are consistent with the lower fertility rate reported earlier in these females. The finding that final follicle growth was fully rescued by postnatal anti-androgen treatment and intrafollicular steroid milieu partially by insulin sensitizer treatment suggest that both androgenic and insulin pathway disruptions contribute to the compromised follicular phenotype of prenatal T-treated females.

Effects of testosterone on the expression levels of AMH, VEGF and HIF-1α in mouse granulosa cells

The present study aimed to investigate the effects of testosterone on mouse granulosa cell morphology, and the expression levels of anti-Müllerian hormone (AMH), vascular endothelial growth factor (VEGF) and hypoxia-inducible factor-1α (HIF-1α). Mouse granulosa cells were isolated and identified, and their morphology was examined using hematoxylin and eosin, F-actin, and follicle-stimulating hormone receptor staining. The mRNA expression levels of AMH, VEGF and HIF-1α were examined using reverse transcription-quantitative polymerase chain reaction, and their protein secretion levels were investigated using enzyme-linked immunosorbent assays. Testosterone treatment did not affect granulosa cell morphology; however, it significantly increased the mRNA expression levels of AMH and VEGF, and the protein secretion levels of AMH, VEGF and HIF-1α. These results suggested that testosterone was able to regulate the functions of granulosa cells by upregulating the expression levels of AMH, VEGF and HIF-1α.

Effect of Prenatal and Neonatal Anti-Androgen Flutamide Treatment on Aquaporin 5 Expression in the Adult Porcine Ovary

The growth of ovarian follicles is accompanied by fluid-filled antrum formation. Water movement within the follicular wall is predominantly transcellular via membranous water channels named aquaporins (AQPs). Androgens are important regulators of mammalian folliculogenesis, and their prenatal and/or neonatal deficiency affects female fertility in adulthood. Therefore, this study was performed to determine whether gestational or neonatal exposure to the anti-androgen flutamide influences androgen-dependent AQP5 expression in pre-antral and large antral follicles of adult pigs. Flutamide was injected into pregnant gilts between days 80 and 88 of gestation and into female piglets between days 2 and 10 post-natally. The ovaries were collected from flutamide-treated and non-treated (control) sexually mature pigs. In pre-antral follicles, AQP5 mRNA and protein levels were both downregulated following maternal (p < 0.01 and p < 0.01, respectively) and neonatal (p < 0.01 and p < 0.01, respectively) flutamide exposure. Likewise, the expression of mRNA (p < 0.01 and p < 0.001, respectively) and protein (p < 0.05 and p < 0.01, respectively) for AQP5 were diminished in large antral follicles in both groups. Immunohistochemistry showed decreased intensity of AQP5 immunoreaction in pre-antral (p < 0.01) and large antral (p < 0.001) follicles following flutamide treatment. Moreover, radioimmunological analysis revealed that changes observed in AQP5 expression corresponded with diminished follicular androgens production after both maternal (p < 0.05 and p < 0.05, respectively) and neonatal (p < 0.05 and p < 0.01, respectively) flutamide administration. Therefore, AQP5 appears to be a potential regulator of follicular fluid accumulation, under androgen control, and may be a key factor in antral follicle growth.

Developmental Programming: Prenatal and Postnatal Androgen Antagonist and Insulin Sensitizer Interventions Prevent Advancement of Puberty and Improve LH Surge Dynamics in Prenatal Testosterone-Treated Sheep

Prenatal T excess induces maternal hyperinsulinemia, early puberty, and reproductive/metabolic defects in the female similar to those seen in women with polycystic ovary syndrome. This study addressed the organizational/activational role of androgens and insulin in programming pubertal advancement and periovulatory LH surge defects. Treatment groups included the following: 1) control; 2) prenatal T; 3) prenatal T plus prenatal androgen antagonist, flutamide; 4) prenatal T plus prenatal insulin sensitizer, rosiglitazone; 5) prenatal T and postnatal flutamide; 6) prenatal T and postnatal rosiglitazone; and 7) prenatal T and postnatal metformin. Prenatal treatments spanned 30-90 days of gestation and postnatal treatments began at approximately 8 weeks of age and continued throughout. Blood samples were taken twice weekly, beginning at approximately 12 weeks of age to time puberty. Two-hour samples after the synchronization with prostaglandin F2α were taken for 120 hours to characterize LH surge dynamics at 7 and 19 months of age. Prenatal T females entered puberty earlier than controls, and all interventions prevented this advancement. Prenatal T reduced the percentage of animals having LH surge, and females that presented LH surge exhibited delayed timing and dampened amplitude of the LH surge. Prenatal androgen antagonist, but not other interventions, restored LH surges without normalizing the timing of the surge. Normalization of pubertal timing with prenatal/postnatal androgen antagonist and insulin sensitizer interventions suggests that pubertal advancement is programmed by androgenic actions of T involving insulin as a mediary. Restoration of LH surges by cotreatment with androgen antagonist supports androgenic programming at the organizational level.

Steroidogenic versus Metabolic Programming of Reproductive Neuroendocrine, Ovarian and Metabolic Dysfunctions

The susceptibility of the reproductive system to early exposure to steroid hormones has become a major concern in our modern societies. Human fetuses are at risk of abnormal programming via exposure to endocrine disrupting chemicals, inadvertent use of contraceptive pills during pregnancy, as well as from excess exposure to steroids due to disease states. Animal models provide an unparalleled resource to understand the developmental origin of diseases. In female sheep, prenatal exposure to testosterone excess results in an array of adult reproductive disorders that recapitulate those seen in women with polycystic ovary syndrome (PCOS), including disrupted neuroendocrine feedback mechanisms, increased pituitary sensitivity to gonadotropin-releasing hormone, luteinizing hormone excess, functional hyperandrogenism, and multifollicular ovarian morphology culminating in early reproductive failure. Prenatal testosterone treatment also leads to fetal growth retardation, insulin resistance, and hypertension. Mounting evidence suggests that developmental exposure to an improper steroidal/metabolic environment may mediate the programming of adult disorders in prenatal testosterone-treated females, and these defects are maintained or amplified by the postnatal sex steroid and metabolic milieu. This review addresses the steroidal and metabolic contributions to the development and maintenance of the PCOS phenotype in the prenatal testosterone-treated sheep model, including the effects of prenatal and postnatal treatment with an androgen antagonist or insulin sensitizer as potential strategies to prevent/ameliorate these dysfunctions. Insights obtained from these intervention strategies on the mechanisms underlying these defects are likely to have translational relevance to human PCOS.

Antimullerian hormone and its receptor gene expression in prenatally androgenized female rats

BACKGROUND

Anti-mullerian hormone (AMH) levels reflect the number of small antral follicles in ovaries and expression changes of AMH and its receptor are suspected to be involved in the pathogenesis of polycystic ovary syndrome (PCOS).

OBJECTIVES

The aim of this study was to evaluate gene expression of AMH and its receptor in immature and adult rats prenatally exposed to androgen excess.

MATERIALS AND METHODS

Six pregnant Wistar rats in the experimental group were treated by subcutaneous injection of 5 mg free testosterone on day 20 of pregnancy, while controls (n = 6) received only 500 mL of solvent. Female pups of each mother were randomly divided into three groups as day 0 (newborn), 10-day old and days 75-85 (adult). RNAs were extracted from ovarian tissues and relative expression levels for AMH and its receptor genes were measured using TaqMan Real-Time PCR. Serum AMH and testosterone levels were measured using ELISA method.

RESULTS

Relative AMH expression decreased in newborns, 10-day olds and adults (0.806, 0.443 and 0.809 fold, respectively). AMHR expression was higher in newborns and adults (1.432 and 1.057 fold, respectively), while it decreased by 0.263 fold in 10-day olds, although none of them were significant (P > 0.05). In addition, AMH levels were consistent with the results of gene expression. Testosterone hormone levels from 10 day-olds to adults were significantly increased in both study groups (P = 0.016).

CONCLUSIONS

While AMH receptor expression was higher in experimental rats, their serum concentrations of AMH were decreased. Further researches with greater sample sizes and measurement of bioactive forms of hormones are recommended to confirm the findings of this study.

Developmental programming: prenatal steroid excess disrupts key members of intraovarian steroidogenic pathway in sheep

Prenatal testosterone (T) excess disrupts ovarian cyclicity and increases circulating estradiol levels as well as follicular recruitment and persistence culminating in multifollicular ovary similar to women with polycystic ovary syndrome. We tested whether prenatal T excess, by androgenic or estrogenic action, disrupts the steroid biosynthetic machinery in sheep in a cell-, follicle stage-, age-, and treatment-specific manner consistent with the ovarian disruptions and increased estradiol release. Impact of T/dihydrotestosterone (DHT) treatments from days 30-90 of gestation on steroidogenic acute regulatory protein, 3β-hydroxysteroid dehydrogenase, cytochrome P-450 17α-hydroxylase/C17, 20-lyase (CYP17A1), and cytochrome P-450 aromatase (CYP19A1) were examined on fetal day 90, 140 and 10 months (postpubertal), and 21 months (adult, no DHT group) of age by immunohistochemistry. All 4 markers changed in a cell-, follicle stage-, and age-specific manner. Both treatments increased steroidogenic acute regulatory protein expression in preantral follicles of postpubertal and adult females. Effects of prenatal T and DHT on 3β-hydroxysteroid dehydrogenase differed in a follicle- and age-specific manner. CYP17A1 was reduced in the theca interna of antral follicles by T, but not DHT, in 10- and 21-month-old females. CYP19A1 was reduced by both T and DHT at all ages barring an increase on fetal day 140. Reduced granulosa CYP19A1 and thecal CYP17A1 in adults likely disrupt the intrafollicular androgen/estrogen balance contributing to follicular persistence. The reduced thecal CYP17A1 expression suggests that the hyperandrogenic ovarian phenotype may originate from increased enzyme activity or alternatively via a different isoform of CYP17. The reduced CYP19A1 in antral follicles of adults indicates that the increased circulating estradiol release likely arises from the increased number of persisting follicles.

Reproduction Symposium: developmental programming of reproductive and metabolic health

Inappropriate programming of the reproductive system by developmental exposure to excess steroid hormones is of concern. Sheep are well suited for investigating developmental origin of reproductive and metabolic disorders. The developmental time line of female sheep (approximately 5 mo gestation and approximately 7 mo to puberty) is ideal for conducting sequential studies of the progression of metabolic and/or reproductive disruption from the developmental insult to manifestation of adult consequences. Major benefits of using sheep include knowledge of established critical periods to target adult defects, a rich understanding of reproductive neuroendocrine regulation, availability of noninvasive approaches to monitor follicular dynamics, established surgical approaches to obtain hypophyseal portal blood for measurement of hypothalamic hormones, and the ability to perform studies in natural setting thereby keeping behavioral interactions intact. Of importance is the ability to chronically instrument fetus and mother for determining early endocrine perturbations. Prenatal exposure of the female to excess testosterone (T) leads to an array of adult reproductive disorders that include LH excess, functional hyperandrogenism, neuroendocrine defects, multifollicular ovarian morphology, and corpus luteum dysfunction culminating in early reproductive failure. At the neuroendocrine level, all 3 feedback systems are compromised. At the pituitary level, gonadotrope (LH secretion) sensitivity to GnRH is increased. Multifollicular ovarian morphology stems from persistence of follicles as well as enhanced follicular recruitment. These defects culminate in progressive loss of cyclicity and reduced fecundity. Prenatal T excess also leads to fetal growth retardation, an early marker of adult reproductive and metabolic diseases, insulin resistance, hypertension, and behavioral deficits. Collectively, the reproductive and metabolic deficits of prenatal T-treated sheep provide proof of concept for the developmental origin of fertility and metabolic disorders. Studies with the environmental endocrine disruptor bisphenol A (BPA) show that reproductive disruptions found in prenatal BPA-treated sheep are similar to those seen in prenatal T-treated sheep. The ubiquitous exposure to endocrine disrupting compounds with steroidogenic potential via the environment and food sources calls for studies addressing the impact of developmental exposure to environmental steroid mimics on reproductive function.

[What's new in 2014 about anti-Müllerian hormone?]

The existence of the anti-Müllerian hormone (AMH) has been postulated by Professor Alfred Jost to explain the regression of the Müllerian ducts during male sexual differentiation. Since then, AMH has been purified, its gene and specific receptor, AMHR-II have been cloned. Further, the signaling pathways were identified and it has been observed that AMH was produced by the granulosa cells of growing follicles. From the 2000s, unexpected roles of AMH have been highlighted, reactivating international research on this hormone. It is now well established that AMH plays a key role in the follicular recruitment and development. Over the past years, serum AMH measurements have been proposed as a marker of the follicular ovarian status, and a predictor of assisted reproductive cycles. AMH is also useful to assess the effectiveness of treatment of some gynecological tumors. This article is a review of the past five years advances on the regulation of the expression of AMH and its specific receptor AMHR-II in female.

Effect of anti-Mullerian hormone in culture medium on quality of mouse oocytes matured in vitro

Anti-mullerian hormone (AMH) is thought to reflect the growth of follicles and the ovarian function. However, the role of AMH in culture medium during in vitro maturation (IVM) on oocyte quality and subsequent development potential is unclear. The objective of this study is to investigate the effect of recombinant human AMH (rh-AMH) supplemented into IVM medium on oocyte quality. Cumulus-oocyte complexes (COCs) were obtained from ICR mice and cultured in vitro with the different concentrations (0–1,000 ng/ml) of rh-AMH. Following 16–18 h of culture, quantitative PCR and ELISA were performed to analyze GDF9 and BMP15 mRNA expression and protein production from the oocytes. Subsequently, in vitro fertilization (IVF) and early embryonic development were employed to further evaluate the quality of in vitro matured oocytes. The results showed that AMH was only expressed in cumulus cells but not in the oocytes. However, AMH most specific receptor, AMHR-II, was expressed in both oocytes and cumulus cells. The levels of GDF9 and BMP15 expression and blastocyst formation rate were significantly increased (p<0.05) when the IVM medium was supplemented with 100 ng/ml of rh-AMH. With AdH1-SiRNA/AMH for knocking down of AMH expression during IVM significantly reduced (p<0.05) the levels of GDF9 and BMP15 expression and blastocysts formation rate. These results suggest that AHM improves oocytes quality by up-regulating GDF9 and BMP15 expressions during IVM.

The time of prenatal androgen exposure affects development of polycystic ovary syndrome-like phenotype in adulthood in female rats

BACKGROUND

Polycystic ovary syndrome (PCOS) is one of the most common reproductive disorders in women. Previous studies have shown that prenatal exposure of female fetuses to androgen can be considered an important factor in the development of PCOS.

OBJECTIVES

In the present study we aimed to examine the effects of prenatal exposure of female rat fetuses to previously documented doses of testosterone on different embryonic days on the development of PCOS phenotype in adulthood.

MATERIALS AND METHODS

Pregnant rats were divided into four groups, experimental and control groups. Three mg of free testosterone was administered subcutaneously to experimental group 1 on gestational days 16-19, daily and 20 mg on day 20, to experimental group 2, and the controls received solvent at the same times. Female offspring of these mothers aged between 90-100 days were examined for development and function of the reproductive system. Independent-sample student t test was used to compare the results between the experimental groups and controls.

RESULTS

Anogenital distance (P < 0.001) and clitoris length were significantly increased in the offspring of both experimental groups (P < 0.001 and P < 0.05 respectively). Nipples were not formed in the offspring of experimental group 1, whereas in experimental group 2 the number of nipples was unchanged. Vaginal length was significantly decreased in the offspring of experimental group 1 (P < 0.001), whereas in experimental group 2, no significant difference was observed. In the offspring of experimental group 1, hormonal profiles did not differ, but in experimental group 2, levels of testosterone (P < 0.05) and LH (P < 0.01) were significantly increased, but estrogen (P < 0.05) and anti-Mullerian hormone levels (P < 0.001) were significantly decreased. A significant increase in the number of preantral and antral follicles was observed in the ovaries of offspring of experimental group 1 (P < 0.05); whereas there was no such a difference in experimental group 2.

CONCLUSIONS

The time of prenatal exposure to androgens may have a significant role in the development of PCOS. Increased prenatal androgen levels are associated with hormonal changes and morphological disorders of the reproductive system. Therefore, avoiding exposure to androgen excess during critical periods of fetal development may prevent or reduce adulthood PCOS manifestations caused by prenatal excess androgen.

Wnt4, a pleiotropic signal for controlling cell polarity, basement membrane integrity, and antimüllerian hormone expression during oocyte maturation in the female follicle

Wnt4 is a key signal that channels the developmental fate of the indifferent mammalian gonad toward the ovary, but whether Wnt4 has later roles during ovary development remains unknown. To investigate this, we inactivated the Wnt4 gene by crossing Amhr2Cre and doxycycline-inducible Rosa(rtTA)-knock-in Cre mice with mice carrying a floxed Wnt4 allele and used a novel Wnt4(mCherry)-knock-in mouse. In these models, ovarian folliculogenesis was compromised, and female fertility was severely reduced, and Wnt4 deficiency eventually led to premature ovarian failure. These anomalies were associated with cell polarity defects in the follicle. Within the follicle, laminin and type IV collagen assembled ectopic basement membrane-like structures, the cell adherens junction components N-cadherin and β-catenin lost their polarized expression pattern, and expression of the gap junction protein connexin 43 was reduced by ~30% when compared with that of the controls. Besides these changes, expression of antimüllerian hormone (Amh) was inhibited in the absence of Wnt4 signaling in vivo. Consistent with this, Wnt4 signaling up-regulated Amh gene expression in KK1 cells in vitro. Thus, Wnt4 signaling is necessary during maturation of the ovarian follicles, where it coordinates expression of Amh, cell survival, and polarized organization of the follicular cells.

Ontogeny of the ovary in polycystic ovary syndrome

Activation of primordial follicles into the growing pool, selection of the dominant follicle, and its eventual ovulation require complex endocrine and metabolic interactions as well as intraovarian paracrine signals to coordinate granulosa cell proliferation, theca cell differentiation, and oocyte maturation. Early preantral follicle development relies mostly upon mesenchymal-epithelial cell interactions, intraovarian paracrine signals, and oocyte-secreted factors, whereas development of the antral follicle depends on circulating gonadotropins as well as locally derived regulators. In women with polycystic ovary syndrome (PCOS), ovarian hyperandrogenism, hyperinsulinemia from insulin resistance, and altered intrafollicular paracrine signaling perturb the activation, survival, growth, and selection of follicles, causing accumulation of small antral follicles within the periphery of the ovary, giving it a polycystic morphology. Altered adipocyte-ovarian interactions further compound these adverse events on follicle development and also can harm the oocyte, particularly in the presence of increased adiposity. Finally, endocrine antecedents of PCOS occur in female infants born to mothers with PCOS, which suggests that interactions between genes and the maternal-fetal hormonal environment may program ovarian function after birth.

Diagnosis and treatment of polycystic ovarian syndrome in adolescents

PURPOSE OF REVIEW

To review what is understood about the pathophysiology of polycystic ovarian syndrome (PCOS), the diagnostic challenges of PCOS in adolescent women, associated risk factors, as well as the best evidence-based treatment options for adolescence.

RECENT FINDINGS

Diagnosing PCOS in adolescents requires a unique set of criteria for which no single marker currently exists. Adolescents at high risk for developing the syndrome are congenital virilization, low birth weight, premature pubarche, central precocious puberty, large for gestational age girls born to overweight mothers, obesity syndromes, insulin-resistant features, and girls born to parents with PCOS, central obesity, or diabetes in whom PCOS ought to be suspected when associated with irregular menses. Insulin, hyperandrogenemia, and adipocytokines are integral players in the pathophysiology of PCOS. PCOS may be an inheritable trait; however, no gene has yet been identified. Quality of life remains a concern for young women with PCOS. Lifestyle modifications geared to prevent long-term sequelae remain the first-line treatment in conjunction with oral contraceptive pills.

SUMMARY

Identifying PCOS in adolescents remains a diagnostic dilemma, but early intervention and treatment can improve long-term health.

The role of anti-Müllerian hormone (AMH) during follicle development in a monovulatory species (sheep)

Knockout studies in mice have suggested that anti-Müllerian hormone (AMH) modulates primordial follicle recruitment and the response of growing follicles to FSH. Little is known of the physiology of AMH in monovular species, despite intense clinical interest in this factor. Using sheep as a model, we sought to investigate the functional role of AMH in modulating follicle development in monovular species. In contrast to the rodent, the results indicate that AMH does not affect the rate of primordial follicle recruitment but appears to regulate the rate at which follicles progress through the gonadotropin-responsive phase, during which it is maximally expressed. Thus, knockdown of AMH bioactivity by active immunization lead to a decline in the population of gonadotropin-responsive preantral and small antral follicles (P < 0.01) and increases in both the number of gonadotropin-dependent antral follicles (P < 0.01) and ovulation rate (P < 0.05). These in vivo findings were consistent with the results of other studies examining the pattern of expression of AMH, which was negatively correlated with aromatase (P < 0.001), and in vitro supplementation experiments, which supported an inhibitory role for AMH in modulating the response of both theca and granulosa cells to LH and FSH, respectively. The elucidation of a functional relationship between AMH and LH-stimulated thecal androgen production may be significant in terms of the etiology of common forms of anovulatory infertility in women. Furthermore, the observed increase in both the number of recruitable antral follicles and ovulatory quota in response to AMH knockdown may have therapeutic value in women who respond poorly to ovarian stimulation.