Contributions of androgen and estrogen to fetal programming of ovarian dysfunction

Advances in biomaterials-based tissue engineering for regeneration of female reproductive tissues

The anatomical components of the female reproductive system-comprising the ovaries, uterus, cervix, vagina, and fallopian tubes-interact intricately to provide the structural and hormonal support essential for reproduction. However, this system is susceptible to various detrimental factors, both congenital and acquired, that can impair fertility and adversely affect quality of life. Recent advances in bioengineering have led to the development of sophisticated three-dimensional models that mimic the complex architecture and functionality of reproductive organs. These models, incorporating diverse cell types and tissue layers, are crucial for understanding physiological processes within the reproductive tract. They offer insights into decidualization, ovulation, folliculogenesis, and the progression of reproductive cancers, thereby enhancing personalized medical treatments and addressing female infertility. This review highlights the pivotal role of tissue engineering in diagnosing and treating female infertility, emphasizing the importance of considering factors like biocompatibility, biomaterial selection, and mechanical properties in the design of bioengineered systems. The challenge of replicating the functionally specialized and structurally complex organs, such as the uterus and ovary, underscores the need for reliable techniques that improve morphological and functional restoration. Despite substantial progress, the goal of creating a fully artificial female reproductive system is still a challenge. Nonetheless, the recent fabrication of artificial ovaries, uteruses, cervixes, and vaginas marks significant advancements toward this aim. Looking forward, the challenges in bioengineering are expected to spur further innovations in both basic and applied sciences, potentially hastening the clinical adoption of these technologies.

Prenatal phthalate exposure and pubertal development in 16-year-old daughters: reproductive hormones and number of ovarian follicles

STUDY QUESTION

Is there a possible association between prenatal phthalate exposure and late effects in teenage daughters with respect to reproductive hormone levels, uterine volume, and number of ovarian follicles?

SUMMARY ANSWER

Our study showed subtle associations between phthalate metabolite concentrations in maternal serum from pregnancy or cord blood and LH and insulin-like growth factor 1 (IGF-1) levels as well as uterine volume in their daughters 16 years later.

WHAT IS KNOWN ALREADY

Endocrine-disrupting environmental chemicals may adversely affect human reproductive health, and many societies have experienced a trend toward earlier puberty and an increasing prevalence of infertility in young couples. The scientific evidence of adverse effects of foetal exposure to a large range of chemicals, including phthalates, on male reproductive health is growing, but very few studies have explored effects on female reproduction.

STUDY DESIGN, SIZE, DURATION

This follow-up study included 317 teenage daughters who were part of the Copenhagen Mother-Child Cohort, a population-based longitudinal birth cohort of 1210 females born between 1997 and 2002.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A total of 317 female participants (median age 16 years) were examined for weight, height, and menstrual pattern. A serum sample was analysed for concentrations of reproductive hormones, and trans-abdominal 3D ultrasonography was performed to obtain the number of ovarian follicles, ovarian and uterine size. Prenatal maternal serum samples were available for 115 females, and cord blood samples were available for 118 females. These were analysed for concentrations of 32 phthalate metabolites. Weighted quantile sum regression was used for modelling associations of combined prenatal phthalate exposure with the reproductive outcomes in post-menarcheal females.

MAIN RESULTS AND THE ROLE OF CHANCE

In bivariate correlation analyses, negative significant associations were found between several prenatal phthalate metabolite concentrations and serum hormone concentrations (testosterone, 17-OH-progesterone, and IGF-1) as well as number of ovarian follicles in puberty. Positive significant correlations were found between prenatal phthalate exposure and FSH and sex hormone-binding globulin concentrations. Combined analyses of phthalate exposure (weighted quantile sums) showed significant negative associations with IGF-1 concentration and uterine volume as well as a significant positive association with LH concentration.

LIMITATIONS, REASONS FOR CAUTION

Phthalate metabolites were measured in serum from single prenatal maternal blood samples and cord blood samples. Potential concomitant exposure to other endocrine-disrupting environmental chemicals before or after birth was not controlled for. The study population size was limited.

WIDER IMPLICATIONS OF THE FINDINGS

Our results support the need for further research into possible adverse effects of environmental chemicals during foetal development of the female reproductive system.

STUDY FUNDING/COMPETING INTEREST(S)

The work was supported by The Center on Endocrine Disruptors (CeHoS) under The Danish Environmental Protection Agency and The Ministry of Environment and Food (grant number: MST-621-00 065). No conflicts of interest are declared.

TRIAL REGISTRATION NUMBER

N/A.

Intra-ovarian inflammatory states and their associations with embryo quality in normal-BMI PCOS patients undergoing IVF treatment

BACKGROUND

Polycystic ovary syndrome (PCOS) is the main cause of anovulatory infertility in women of reproductive age, and low-grade chronic inflammation plays a key role in the occurrence and development of PCOS. However, obesity, as a likely confounding factor, can affect the inflammatory state of PCOS patients.

OBJECTIVE

The aim of this study was to comprehensively investigate intra-ovarian inflammatory states and their impact on embryo quality in PCOS patients with a normal BMI undergoing IVF treatment.

METHODS

DIA-mass spectrometry-based proteomics and bioinformatic analysis were combined to comprehensively profile the protein expression of granulosa cells (GCs) from 5 normal-BMI PCOS patients and 5 controls. Thirty-four cytokines were further systematically detected in follicular fluid (FF) from 32 age- and BMI-matched normal-BMI patients using Luminex liquid chip suspension technology. Next, the differentially expressed cytokines were evaluated by enzyme-linked immunosorbent assay (ELISA) in 24 newly recruited subjects, and the relationship between these cytokines and embryo quality in PCOS patients was analysed. Finally, these cytokine levels were compared and evaluated in PCOS patients with different androgen levels.

RESULTS

Proteomic analysis showed that the suppression of substance metabolism and steroid biosynthesis, more interestingly, resulted in an enhanced immune and inflammatory response in the GCs of normal-BMI PCOS patients and prompted the involvement of cytokines in this process. Luminex analysis further showed that FF macrophage inflammatory protein-1 beta (MIP-1β) and stromal cell-derived factor-1 alpha (SDF-1α) levels were significantly increased in normal-BMI PCOS patients compared to controls (P = 0.005; P = 0.035, respectively), and the ELISA results were consistent with these findings. Besides, FF MIP-1β showed an inverse correlation with the number of D3 good-quality embryos and the good-quality blastocyst rate in patients with PCOS (P = 0.006; P = 0.003, respectively), which remained significant after correction for multiple comparisons. Moreover, SDF-1α levels had no relationship with embryo development in PCOS patients. Additionally, SDF-1α levels were significantly lower in PCOS patients with high androgen levels than in controls (P = 0.031).

CONCLUSIONS

Local ovarian inflammation was present in normal-BMI PCOS patients, affecting follicular development, and FF MIP-1β may be a potential biomarker associated with embryo quality in normal-BMI PCOS patients.

Developmental programming: Impact of preconceptional and gestational exposure to a real-life environmental chemical mixture on maternal steroid, cytokine and oxidative stress milieus in sheep

BACKGROUND

Gestational exposure to environmental chemicals (ECs) is associated with adverse, sex-specific offspring health effects of global concern. As the maternal steroid, cytokine and oxidative stress milieus can have critical effects on pregnancy outcomes and the programming of diseases in offspring, it is important to study the impact of real-life EC exposure, i.e., chronic low levels of mixtures of ECs on these milieus. Sheep exposed to biosolids, derived from human waste, is an impactful model representing the ECs humans are exposed to in real-life. Offspring of sheep grazed on biosolids-treated pasture are characterized by reproductive and metabolic disruptions.

OBJECTIVE

To determine if biosolids exposure disrupts the maternal steroid, cytokine and oxidative stress milieus, in a fetal sex-specific manner.

METHODS

Ewes were maintained before mating and through gestation on pastures fertilized with biosolids (BTP), or inorganic fertilizer (Control). From maternal plasma collected mid-gestation, 19 steroids, 14 cytokines, 6 oxidative stress markers were quantified. Unpaired t-test and ANOVA were used to test for differences between control and BTP groups (n = 15/group) and between groups based on fetal sex, respectively. Correlation between the different markers was assessed by Spearman correlation.

RESULTS

Concentrations of the mineralocorticoids - deoxycorticosterone, corticosterone, the glucocorticoids - deoxycortisol, cortisol, cortisone, the sex steroids - androstenedione, dehydroepiandrosterone, 16-OH-progesterone and reactive oxygen metabolites were higher in the BTP ewes compared to Controls, while the proinflammatory cytokines IL-1β and IL-17A and anti-inflammatory IL-36RA were decreased in the BTP group. BTP ewes with a female fetus had lower levels of IP-10.

DISCUSSION

These findings suggest that pre-conceptional and gestational exposure to ECs in biosolids increases steroids, reactive oxygen metabolites and disrupts cytokines in maternal circulation, likely contributors to the aberrant phenotypic outcomes seen in offspring of BTP sheep - a translationally relevant precocial model.

The 2D:4D index is associated with the development of excess body weight in adults, but not with the rate of weight loss following bariatric surgery

2D:4D finger length ratio is a proxy of prenatal sex hormone exposure. Prenatal testosterone decreases and prenatal estrogens increase this index. In the current study we investigated whether the 2D:4D index, as a marker of the prenatal hormonal environment, is associated with the development of overweight and obesity in adults, and whether is it correlated with the rate of weight loss in patients after bariatric surgery. We tested 125 adults with obesity (BMI ≥ 30.0 kg/m²), 125 adults with overweight (BMI 25.0–29.9 kg/m²) and 153 persons with normal body weight (BMI < 25 kg/m²) of both sexes. We have found that the development of excessive body weight in men and women, and fat accumulation in the upper arms, thighs and lower legs in women with obesity (but not men) are associated with increased prenatal estrogen exposure. This relationship indicates a new area of activity in the field of obesity prevention. Moreover, it seems that the 2D:4D index (especially of the right hand) may be a useful factor in early prediction of the risk of developing excessive body weight in humans. The rate of weight loss after bariatric surgery is independent of prenatal exposure to sex hormones.

Long-Term Changes in Ovarian Follicles of Gilts Exposed Neonatally to Methoxychlor: Effects on Oocyte-Derived Factors, Anti-Müllerian Hormone, Follicle-Stimulating Hormone, and Cognate Receptors

In this paper, we investigated the effects of neonatal exposure to methoxychlor (MXC), a synthetic organochlorine used as an insecticide with estrogenic, antiestrogenic, and antiandrogenic activities on ovarian follicles of adult pigs. Piglets were injected with MXC (20 μg/kg body weight) or corn oil (controls) from postnatal Day 1 to Day 10 (n = 5 per group). Then, mRNA expression, protein abundance and immunolocalization of growth and differentiation factor 9 (GDF9), bone morphogenetic protein 15 (BMP15), anti-Müllerian hormone (AMH) and cognate receptors (ACVR1, BMPR1A, BMPR1B, TGFBR1, BMPR2, and AMHR2), as well as FSH receptor (FSHR) were examined in preantral and small antral ovarian follicles of sexually mature gilts. The plasma AMH and FSH levels were also assessed. In preantral follicles, neonatal exposure to MXC increased GDF9, BMPR1B, TGFBR1, and BMPR2 mRNAs, while the levels of AMH and BMP15 mRNAs decreased. In addition, MXC also decreased BMP15 and BMPR1B protein abundance. Regarding small antral follicles, neonatal exposure to MXC upregulated mRNAs for BMPR1B, BMPR2, and AMHR2 and downregulated mRNAs for AMH, BMPR1A, and FSHR. MXC decreased the protein abundance of AMH, and all examined receptors in small antral follicles. GDF9 and BMP15 were immunolocalized in oocytes and granulosa cells of preantral follicles of control and treated ovaries. All analyzed receptors were detected in the oocytes and granulosa cells of preantral follicles, and in the granulosa and theca cells of small antral follicles. The exception, however, was FSHR, which was detected only in the granulosa cells of small antral follicles. In addition, MXC decreased the plasma AMH and FSH concentrations. In conclusion, the present study may indicate long-term effects of neonatal MXC exposure on GDF9, BMP15, AMH, and FSH signaling in ovaries of adult pigs. However, the MXC effects varied at different stages of follicular development. It seems that neonatal MXC exposure may result in accelerated initial recruitment of ovarian follicles and impaired cyclic recruitment of antral follicles.

A spatiotemporal steroidogenic regulatory network in human fetal adrenal glands and gonads

Human fetal adrenal glands produce substantial amounts of dehydroepiandrosterone (DHEA), which is one of the most important precursors of sex hormones. However, the underlying biological mechanism remains largely unknown. Herein, we sequenced human fetal adrenal glands and gonads from 7 to 14 gestational weeks (GW) via 10× Genomics single-cell transcriptome techniques, reconstructed their location information by spatial transcriptomics. Relative to gonads, adrenal glands begin to synthesize steroids early. The coordination among steroidogenic cells and multiple non-steroidogenic cells promotes adrenal cortex construction and steroid synthesis. Notably, during the window of sexual differentiation (8-12 GW), key enzyme gene expression shifts to accelerate DHEA synthesis in males and cortisol synthesis in females. Our research highlights the robustness of the action of fetal adrenal glands on gonads to modify the process of sexual differentiation.

Alpha/Beta Hydrolase Domain-Containing Protein 2 Regulates the Rhythm of Follicular Maturation and Estrous Stages of the Female Reproductive Cycle

Mammalian female fertility is defined by a successful and strictly periodic ovarian cycle, which is under the control of gonadotropins and steroid hormones, particularly progesterone and estrogen. The latter two are produced by the ovaries that are engaged in controlled follicular growth, maturation, and release of the eggs, i.e., ovulation. The steroid hormones regulate ovarian cycles via genomic signaling, by altering gene transcription and protein synthesis. However, despite this well-studied mechanism, steroid hormones can also signal via direct, non-genomic action, by binding to their membrane receptors. Here we show, that the recently discovered membrane progesterone receptor α/β hydrolase domain-containing protein 2 (ABHD2) is highly expressed in mammalian ovaries where the protein plays a novel regulatory role in follicle maturation and the sexual cycle of females. Ablation of Abhd2 caused a dysregulation of the estrous cycle rhythm with females showing shortened luteal stages while remaining in the estrus stage for a longer time. Interestingly, the ovaries of Abhd2 knockout (KO) females resemble polycystic ovary morphology (PCOM) with a high number of atretic antral follicles that could be rescued with injection of gonadotropins. Such a procedure also allowed Abhd2 KO females to ovulate a significantly increased number of mature and fertile eggs in comparison with their wild-type littermates. These results suggest a novel regulatory role of ABHD2 as an important factor in non-genomic steroid regulation of the female reproductive cycle.

Androgen-induced epigenetic modulations in the ovary

In recent years, androgens have emerged as critical regulators of female reproduction and women's health in general. While high levels of androgens in women are associated with polycystic ovary syndrome (PCOS), recent evidence suggests that a certain amount of direct androgen action through androgen receptor is also essential for normal ovarian function. Moreover, prenatal androgen exposure has been reported to cause developmental reprogramming of the fetus that manifests into adult pathologies, supporting the Developmental Origins of Health and Disease (DOHaD) hypothesis. Therefore, it has become imperative to understand the underlying mechanism of androgen actions and its downstream effects under normal and pathophysiological conditions. Over the years, there has been a lot of studies on androgen receptor function as a transcriptional regulator in the nucleus as well as androgen-induced rapid extra-nuclear signaling. Conversely, new evidence suggests that androgen actions may also be mediated through epigenetic modulation involving both the nuclear and extra-nuclear androgen signaling. This review focuses on androgen-induced epigenetic modifications in female reproduction, specifically in the ovary, and discusses emerging concepts, latest perceptions, and highlight the areas that need further investigation.

An incremental feeding pattern for Guangdong Small-ear Spotted gilts during gestation: effects on stillbirth rate and muscle weight of progeny

While an appropriate feed intake is crucial for the reproductive performance of sows, there is a lack of recommendations currently for feed allowance of Guangdong Small-ear Spotted gilts during gestation. The effects of 2 different feeding patterns during gestation on the reproductive performance of Guangdong Small-ear Spotted gilts were investigated by assigning 80 gilts to 2 feeding pattern groups with a randomized complete block design in accordance with initial body weight and back fat thickness, followed by treatment with an incremental feeding pattern (IFP) and a concaved feeding pattern, respectively, with no difference in total feed intake. The IFP group showed a significant decrease in the stillbirth rate (P < 0.05) and an upward trend in piglet mean birth weight (P = 0.06). Furthermore, the IFP group exhibited an increase in the weights of stomach, supraspinatus tendon, triceps, and psoas minor in neonatal piglets (P < 0.05). Overall, the results of the present investigation showed that IFP could significantly reduce the stillbirth rate of Guangdong Small-ear Spotted gilts and increase the muscle weight of progeny.

Developmental programming of the female reproductive system-a review

Exposures to adverse conditions in utero can lead to permanent changes in the structure and function of key physiological systems in the developing fetus, increasing the risk of disease and premature aging in later postnatal life. When considering the systems that could be affected by an adverse gestational environment, the reproductive system of developing female offspring may be particularly important, as changes have the potential to alter both reproductive capacity of the first generation, as well as health of the second generation through changes in the oocyte. The aim of this review is to examine the impact of different adverse intrauterine conditions on the reproductive system of the female offspring. It focuses on the effects of exposure to maternal undernutrition, overnutrition/obesity, hypoxia, smoking, steroid excess, endocrine-disrupting chemicals, and pollutants during gestation and draws on data from human and animal studies to illuminate underlying mechanisms. The available data indeed indicate that adverse gestational environments alter the reproductive physiology of female offspring with consequences for future reproductive capacity. These alterations are mediated via programmed changes in the hypothalamic-pituitary-gonadal axis and the structure and function of reproductive tissues, particularly the ovaries. Reproductive programming may be observed as a change in the timing of puberty onset and menopause/reproductive decline, altered menstrual/estrous cycles, polycystic ovaries, and elevated risk of reproductive tissue cancers. These reproductive outcomes can affect the fertility and fecundity of the female offspring; however, further work is needed to better define the possible impact of these programmed changes on subsequent generations.

Associations between foetal size and ovarian development in the pig

It is estimated that intra-uterine growth restricted piglets represent 25 % of the total number of piglets born. Growth restricted female pigs have impaired reproductive performance postnatally. HHowever, when during gestation this phenotype arises is not known. With this study, the aim was to improve the understanding of foetal ovarian development in normal and small foetuses throughout gestation. Female Large White X Landrace foetuses were obtained at gestational day (GD) 45, 60 and 90 (n = 5-6 litters/GD). Histological analysis of GATA4 stained foetal ovaries at GD60 and 90 indicated there were fewer primary follicles (P ≤ 0.05) in the foetuses weighing the least compared to those with a weight similar to the mean for the litter (CTMLW) at GD90. Plasma oestradiol concentrations were less in the foetuses with lesser weights compared with greater weight foetuses at GD90 (P ≤ 0.05). The RNA was extracted from ovaries of the lesser weight and CTMLW foetuses at GD45, 60 and 90 and qPCR was performed to quantify relative abundance of 12 candidate mRNAs for which encoded proteins that modulate ovarian function and development. Gestational changes in relative abundances of CD31, PTGFR, SPP1 and VEGFA mRNA transcripts were observed. Relative abundance of KI67 (P = 0.066) and P53 (P ≤ 0.05) was less in ovaries of the lesser weight compared to CTMLW foetuses at GD60. There was a lesser relative abundance of PTGFR mRNA transcript in ovaries from the foetuses with lesser weight compared to CTMLW foetuses at GD45 and 60 (P ≤ 0.05). These findings indicate that postnatal differences in the reproductive potential of growth restricted females are programmed early in gestation. It is hoped that further investigation will improve the understanding of the relationship between prenatal reproductive development and postnatal reproductive performance.

The Effect of Twin Sex on Menstrual Characteristics

Background and objectives: The purpose of this project is to evaluate the association between twin sex discordance and menstrual characteristics. We hypothesize that sharing the uterus with a male twin can change ovulation programming, hence changing the menstrual cycle characteristics during adulthood. This project could be novel in discovering new physiological mechanisms of hormone exposure and menstrual cycles. Materials and methods: This is a cross-sectional study. We asked females from sex-concordant (n = 1290) and sex-discordant (n = 168) twin pairs in the Washington State Twin Registry about characteristics of menstrual cycles. Generalized Estimating Equation (GEE) analysis was used to compare groups. The main outcome measures included the amount of bleeding, duration of menstruation, the timing of menstruation, length of menstruation, and a number of periods per year. Results: We found a statistically significant association between the amount of menstrual period bleeding and twin sex discordance (0.42 (95% CI 0.18–0.94)). However, twin sex discordance was not associated with period duration, length of menstrual cycle, cycle regularity, or a number of periods per year. Conclusions: Twin sex discordance is not a predictor of clinical characteristics of menstruation during adulthood except for the amount of bleeding. Future studies should focus on the impact of male hormones on the amount of bleeding during menstruation.

Neonatal Exposure to Agonists and Antagonists of Sex Steroid Receptors Affects AMH and FSH Plasma Level and Their Receptors Expression in the Adult Pig Ovary

Simple Summary

The ovarian development and the establishment of ovarian reserve during fetal and/or neonatal life is critical for future reproductive success. Many environmental chemicals are known to negatively affect development and physiology of human and animal ovaries by interfering with endocrine systems, resulting in aberrant reproductive functions. The present study shows the long-term impact of neonatal exposure to agonists and antagonists of sex steroid receptors on AMH and FSH signalling in the ovary of adult pigs. Our findings suggest alteration in ovarian follicle recruitment from ovarian reserve arising from neonatal disruption of androgen/estrogen signalling induced by environmental endocrine active compounds. Everyday use of many endocrine disruptors is already prohibited after their harmful impacts on normal physiology have become known. Nevertheless, market introduction of new chemicals with potential deleterious influence on reproductive physiology has continued. Our outcomes confirm that a neonatal window plays an essential role in the physiological programming of ovarian function in adult pigs. The influence of environmental chemicals on this critical neonatal window needs to be investigated in order to gain a comprehensive view of deleterious interactions between endocrine disrupting chemicals and ovarian function.

Abstract

In this study piglets were injected with testosterone propionate (TP, an androgen), flutamide (FLU, an antiandrogen), 4-tert-octylphenol (OP, an estrogenic compound), ICI 182,780 (ICI, an antiestrogen) or corn oil (controls) between postnatal days 1 and 10 (N = 5/group). Then plasma anti-Müllerian hormone (AMH) and follicle stimulating hormone (FSH) concentration and the expression of their receptors were examined in the adult pig ovary. TP and FLU decreased plasma AMH and FSH concentration. In preantral follicles, TP resulted in upregulation of AMHR2 and FSHR expression, but decreased AMH protein abundance. FLU upregulated AMHR2 expression, while OP increased FSHR mRNA. In small antral follicles, OP upregulated ACVR1 and BMPR1A expression, while FLU increased BMPR1A mRNA. FLU and ICI resulted in upregulation of AMHR2 expression. TP and FLU upregulated AMH expression, while it was downregulated in response to OP or ICI. Moreover, OP and ICI resulted in downregulation of FSHR expression, while FLU decreased FSHR protein abundance. In conclusion, neonatal exposure to either agonist or antagonist of androgen receptor affected AMH and FSH signalling systems in preantral follicles. In small antral follicles these systems were influenced by compounds with estrogenic, antiestrogenic, and antiandrogenic activity. Consequently, these hormonal agents may cause an accelerated recruitment of primordial follicles and affect the cycling recruitment of small antral follicles in pigs.

Morphometric and gene expression analyses of stromal expansion during development of the bovine fetal ovary

During ovarian development stroma from the mesonephros penetrates and expands into the ovarian primordium and thus appears to be involved, at least physically, in the formation of ovigerous cords, follicles and surface epithelium. Cortical stromal development during gestation in bovine fetal ovaries (n=27) was characterised by immunohistochemistry and by mRNA analyses. Stroma was identified by immunostaining of stromal matrix collagen type I and proliferating cells were identified by Ki67 expression. The cortical and medullar volume expanded across gestation, with the rate of cortical expansion slowing over time. During gestation, the proportion of stroma in the cortex and total volume in the cortex significantly increased (P<0.05). The proliferation index and numerical density of proliferating cells in the stroma significantly decreased (P<0.05), whereas the numerical density of cells in the stroma did not change (P>0.05). The expression levels of 12 genes out of 18 examined, including osteoglycin (OGN) and lumican (LUM), were significantly increased later in development (P<0.05) and the expression of many genes was positively correlated with other genes and with gestational age. Thus, the rate of cortical stromal expansion peaked in early gestation due to cell proliferation, whilst late in development expression of extracellular matrix genes increased.

Androgenic and estrogenic indices in human newborns and infants: the MIREC-ID study

Prenatal sex steroid exposure plays an important role in determining child development. Yet, measurement of prenatal hormonal exposure has been limited by the paucity of newborn/infant data and the invasiveness of fetal hormonal sampling. Here we provide descriptive data from the MIREC-ID study (n=173 girls; 162 boys) on a range of minimally invasive physical indices thought to reflect prenatal exposure to androgens [anogenital distances (AGDs); penile length/width, scrotal/vulvar pigmentation], to estrogens [vaginal maturation index (VMI) - the degree of maturation of vaginal wall cells] or to both androgens/estrogens [2nd-to-4th digit ratio (2D:4D); areolar pigmentation, triceps/sub-scapular skinfold thickness, arm circumference]. VMI was found to be associated with triceps skinfold thickness (β=0.265, P=0.005), suggesting that this marker may be sensitive to estrogen levels produced by adipose tissue in girls. Both estrogenic and androgenic markers (VMI: β=0.338, P=0.031; 2D:4D - right: β=-0.207, P=0.040; left: β=-0.276, P=0.006; AGD-fourchette - β=0.253, P=0.036) were associated with areolar pigmentation in girls, supporting a role for the latter as an index of both androgen and estrogen exposure. We also found AGD-penis (distance from the anus to the penis) to be associated with scrotal pigmentation (β=0.290, P=0.048), as well as right arm circumference (β=0.462, P<0.0001), supporting the notion that these indices may be used together as markers of androgen exposure in boys. In sum, these findings support the use of several physical indices at birth to convey a more comprehensive picture of prenatal exposure to sex hormones.

Maternal β-hydroxy-β-methylbutyrate (HMB) supplementation during pregnancy affects early folliculogenesis in the ovary of newborn piglets

Beta-hydroxy-beta-methylbutyrate (HMB) is a leucine metabolite with protein anabolic effects. This study was designed to determine whether prenatal HMB treatment has an effect on oogenesis and folliculogenesis in the ovary of newborn piglets. HMB decreased the number of egg nests and primordial follicles and increased the pool of developing follicles compared to the control group. Although the percentage of TUNEL-positive oocytes within the egg nests was higher in HMB-treated group no increase in the Bax/Bcl-2 ratio and active caspase-3 expression was observed. Moreover, the granulosa cell proliferation index and StAR protein expression were higher in HMB-treated group. In contrast to the control group, the expression of E-cadherins was reduced after the HMB treatment. In addition, a significant increase in the serum level of gonadotropins and steroid hormones was detected in HMB-treated piglets. In conclusion, prenatal HMB treatment dysregulates hormonal homeostasis which impairs early folliculogenesis in piglets.

Role of Maternal Dietary Protein and Amino Acids on Fetal Programming, Early Neonatal Development, and Lactation in Swine

Simple Summary

Dietary protein is an important nutrient source for sows, necessary for not only growth and production, but also other physiological functions. Protein limitations in maternal diets have the potential to impair fetal myogenesis, while excess maternal dietary protein appears to only have minor effects on early fetal muscle formation. Effects of maternal protein deficiency on increased fat deposition in porcine neonates is inconsistent with gene expressions in the neonates. Sufficient maternal dietary protein can enhance porcine milk protein and fat concentration. Understanding the function of protein and amino acids in sows and the effects on their offspring can provide rational approaches for the regulation of piglet growth and further improvements in meat quality in the future.

Abstract

Maternal nutrition plays a vital role in fetal development, early development of neonates, and lactation and regulates the lifetime productivity of offspring. During pregnancy, maternal nutrition alters expression of the fetal genome and the development of tissues and organs via fetal programming. After parturition, maternal nutrition continues to regulate growth and development of piglets through maternal milk, which contains carbohydrates, lipids, proteins and oligosaccharides. Thus, deficiencies in maternal nutrition are detrimental to development of piglets, which can lead to inefficient growth and decreased carcass merit. Protein is an important nutritional component for sows, which not only functions in muscle development, but also plays a vital role in embryonic and neonatal development and lactation. Although effects of maternal undernutrition on neonatal development have been widely studied in sows, the function of different maternal dietary protein levels on fetal development, neonatal growth and lactation performance of sows is largely unknown. Determination of the effects and underlying mechanisms of maternal dietary protein levels on development of piglets is vital to the pork industry. Therefore, we summarized recent reports regarding mechanisms of effects of maternal protein levels on regulation of conceptus growth and early postnatal development though uterine fetal programming and lactation in swine.

Sex differences in maternal gestational hypertension-induced sensitization of angiotensin II hypertension in rat offspring: the protective effect of estrogen

Recent studies demonstrate that maternal hypertension during pregnancy sensitizes an angiotensin (ANG) II-induced increase in blood pressure (BP) in adult male offspring that was associated with upregulation of mRNA expression of several renin-angiotensin-aldosterone system (RAAS) components and NADPH oxidase in the lamina terminalis (LT) and paraventricular nucleus (PVN). The purpose of the present study was to test whether there are sex differences in the maternal hypertension-induced sensitization of ANG II hypertension, and whether sex hormones are involved in the sensitization process. Male offspring of hypertensive dams showed an enhanced hypertensive response to systemic ANG II when compared with male offspring of normotensive dams and to female offspring of either normotensive or hypertensive dams. Castration did not alter the hypertensive response to ANG II in male offspring. Intact female offspring had no upregulation of RAAS components and NADPH oxidase in the LT and PVN, whereas ovariectomy (OVX) upregulated mRNA expression of several RAAS components and NADPH oxidase in these nuclei and induced a greater increase in the pressor response to ANG II in female offspring of hypertensive dams compared with female offspring of normotensive dams. This enhanced increase in BP was partially attenuated by 17β-estradiol replacement in the OVX offspring of hypertensive dams. The results suggest that maternal hypertension induces a sex-specific sensitization of ANG II-induced hypertension and mRNA expression of brain RAAS and NADPH oxidase in offspring. Female offspring are protected from maternal hypertension-induced sensitization of ANG II hypertension, and female sex hormones are partially responsible for this protective effect.

Early sex-dependent differences in response to environmental stress

Developmental plasticity enables the appearance of long-term effects in offspring caused by exposure to environmental stressors during embryonic and foetal life. These long-term effects can be traced to pre- and post-implantation development, and in both cases, the effects are usually sex specific. During preimplantation development, male and female embryos exhibit an extensive transcriptional dimorphism mainly driven by incomplete X chromosome inactivation. These early developmental stages are crucial for the establishment of epigenetic marks that will be conserved throughout development, making it a particularly susceptible period for the appearance of long-term epigenetic-based phenotypes. Later in development, gonadal formation generates hormonal differences between the sexes, and male and female placentae exhibit different responses to environmental stressors. The maternal environment, including hormones and environmental insults during pregnancy, contributes to sex-specific placental development that controls genetic and epigenetic programming during foetal development, regulating sex-specific differences, including sex-specific epigenetic responses to environmental hazards, leading to long-term effects. This review summarizes several human and animal studies examining sex-specific responses to environmental stressors during both the periconception period (caused by differences in sex chromosome dosage) and placental development (caused by both sex chromosomes and hormones). The identification of relevant sex-dependent trajectories caused by sex chromosomes and/or sex hormones is essential to define diagnostic markers and prevention/intervention protocols.

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.

LINE1 CpG-DNA Hypomethylation in Granulosa Cells and Blood Leukocytes Is Associated With PCOS and Related Traits

CONTEXT

Altered global DNA methylation is indicative of epigenomic instability concerning chronic diseases. Investigating its incidence and association with polycystic ovary syndrome (PCOS) is essential to understand the etiopathogenesis of this disorder.

OBJECTIVES

We assessed global DNA methylation differences in peripheral blood leukocytes (PBLs) and cumulus granulosa cells (CGCs) of controls and women with PCOS; and their association with PCOS and its traits.

DESIGN, SETTING, PARTICIPANTS, MAIN OUTCOME MEASURE

This study included a total of 102 controls and women with PCOS. Forty-one women undergoing controlled ovarian hyperstimulation (COH) and 61 women not undergoing COH were recruited from in vitro fertilization (IVF) and infertility clinics. DNA methylation was measured by ELISA for 5'-methyl-cytosine content and bisulfite sequencing of 5'-untranslated region (5'-UTR) of long interspersed nucleotide element-1 (LINE1/L1).

RESULTS

Total 5'-methyl-cytosine and L1 methylation levels in PBLs and CGCs were similar between controls and women with PCOS. Methylation assessed at CpG sites of L1 5'-UTR revealed a single CpG-site (CpG-4) to be consistently hypomethylated in PBLs of both PCOS groups and CGCs of stimulated PCOS group. In unstimulated women, hypomethylation at CpG-4 was strongly associated with PCOS susceptibility, whereas in stimulated group it showed strong associations with PCOS and its hormonal traits. Furthermore, CGCs demonstrated consistent global and CpG-DNA hypomethylation relative to PBLs, irrespective of normal or disease states.

CONCLUSION

Our study revealed strong association of single hypomethylated CpG-site with PCOS. Identification and characterization of more such methyl-CpG signatures in repetitive elements in larger study populations would provide valuable epigenetic insights into PCOS.

Are 2D:4D finger-length ratios an indicator of androgenetic alopecia in males?

BACKGROUND

Although the pathogenesis of androgenetic alopecia is not completely understood, the roles of genetic susceptibility and androgens are well-known. A lower ratio of the second digit (index finger = 2D) to the fourth digit (ring finger = 4D) length has been hypothesized to reflect prenatal androgen exposure and/or higher sensitivity to androgens.

OBJECTIVES

To determine the relationship between the second to fourth digit length ratio and androgenetic alopecia.

METHODS

Finger length measurements were made by a digital vernier calliper. Androgenetic alopecia severity was assessed using the Hamilton-Norwood scale. Subjects with an androgenetic alopecia score of grade III or more were included in the study.

RESULTS

A total of 189 males with androgenetic alopecia and 171 healthy controls were enrolled in the study. The age range of participants was 19-65 years. The 2D:4D ratios in patients with androgenetic alopecia were significantly lower than those of healthy controls for the right hand; however, no significant difference was found for the left hand. Average 2D:4D ratios in androgenetic alopecia patients were also lower than in controls. No significant relationship was observed between androgenetic alopecia severity and 2D:4D ratios.

CONCLUSION

Our data support the anatomical evidence of in utero androgen exposure and/or an individual’s sensitivity to androgens in patients with androgenetic alopecia. Furthermore, the right hand 2D:4D ratio might be an indicator of androgenetic alopecia development.

Pathologic significance of SET/I2PP2A-mediated PP2A and non-PP2A pathways in polycystic ovary syndrome (PCOS)

SET (SE translocation, SET), a constitutive inhibitor of protein phosphatase 2A (PP2A), is a multifunctional oncoprotein involved in DNA replication, histone modification, nucleosome assembly, gene transcription and cell proliferation. It is widely expressed in human tissues including the gonadal system and brain. Intensive studies have shown that overexpressed SET plays an important role in the development of Alzheimer's disease (AD), and may also contribute to the malignant transformation of breast and ovarian cancers. Recent studies indicated that through interaction with PP2A, SET may upregulate androgen biosynthesis and contribute to hyperandrogenism in polycystic ovary syndrome (PCOS) patients. This review article summarizes data concerning the SET expression in ovaries from PCOS and normal women, and analyzes the role/regulatory mechanism of SET for androgen biosynthesis in PCOS, as well as the significance of this action in the development of PCOS. The potential value of SET-triggered pathway as a therapeutic target and the application of anti-SET reagents for treating hyperandrogenism in PCOS patients are also discussed.

Adverse Reproductive and Developmental Health Outcomes Following Prenatal Exposure to a Hydraulic Fracturing Chemical Mixture in Female C57Bl/6 Mice

Unconventional oil and gas operations using hydraulic fracturing can contaminate surface and groundwater with endocrine-disrupting chemicals. We have previously shown that 23 of 24 commonly used hydraulic fracturing chemicals can activate or inhibit the estrogen, androgen, glucocorticoid, progesterone, and/or thyroid receptors in a human endometrial cancer cell reporter gene assay and that mixtures can behave synergistically, additively, or antagonistically on these receptors. In the current study, pregnant female C57Bl/6 dams were exposed to a mixture of 23 commonly used unconventional oil and gas chemicals at approximately 3, 30, 300, and 3000 μg/kg·d, flutamide at 50 mg/kg·d, or a 0.2% ethanol control vehicle via their drinking water from gestational day 11 through birth. This prenatal exposure to oil and gas operation chemicals suppressed pituitary hormone concentrations across experimental groups (prolactin, LH, FSH, and others), increased body weights, altered uterine and ovary weights, increased heart weights and collagen deposition, disrupted folliculogenesis, and other adverse health effects. This work suggests potential adverse developmental and reproductive health outcomes in humans and animals exposed to these oil and gas operation chemicals, with adverse outcomes observed even in the lowest dose group tested, equivalent to concentrations reported in drinking water sources. These endpoints suggest potential impacts on fertility, as previously observed in the male siblings, which require careful assessment in future studies.

Developmental and Functional Effects of Steroid Hormones on the Neuroendocrine Axis and Spinal Cord

This review highlights the principal effects of steroid hormones at central and peripheral levels in the neuroendocrine axis. The data discussed highlight the principal role of oestrogens and testosterone in hormonal programming in relation to sexual orientation, reproductive and metabolic programming, and the neuroendocrine mechanism involved in the development of polycystic ovary syndrome phenotype. Moreover, consistent with the wide range of processes in which steroid hormones take part, we discuss the protective effects of progesterone on neurodegenerative disease and the signalling mechanism involved in the genesis of oestrogen-induced pituitary prolactinomas.

Prenatal exposure to persistent organochlorine pollutants and female reproductive function in young adulthood

BACKGROUND

The biopersistent organochlorine pollutants dichlorodiphenyldichloroethylene (p,p'-DDE), hexachlorobenzene (HCB) and polychlorinated biphenyls (PCBs) can be detected in humans worldwide. The chemicals can cross the placenta and may interfere with endogenous hormonal homeostasis.

OBJECTIVES

To investigate effects on female reproduction following intrauterine exposure to selected biopersistent organochlorines.

METHODS

We used data from a Danish pregnancy cohort with follow-up on 436 eligible daughters at approximately 20years of age. Information on age of menarche (n=335), menstrual cycle length (n=230) and serum concentrations of reproductive hormones (n=243) was obtained. Number of antral follicles was counted by vaginal ultrasound (n=147). Of 244 daughters who attended clinical examination, 170 used hormonal contraceptives and 74 were non-users. Concentrations of p,p'-DDE, HCB and six PCB congeners were analysed in maternal serum samples obtained in pregnancy week 30.

RESULTS

Age of menarche and menstrual cycle length were found not to be statistically significant associated with prenatal organochlorine exposure. Among non-users of hormonal contraceptives with information on antral follicle number (n=43), daughters exposed to the highest tertile of p,p'-DDE had 28% (95% confidence interval (95% CI): 5; 46%) lower follicle number compared to the low-level exposed reference group. Those exposed to medium and higher levels of HCB had 30% (95% CI: 5; 48%) and 28% (95% CI: 7; 44%) lower follicle number compared to the reference group. Furthermore, maternal serum HCB concentrations were inversely associated with free androgen index among non-users of hormonal contraceptives (n=73). These associations were not found in users of hormonal contraceptives.

CONCLUSIONS

Among non-users of hormonal contraceptives, we found indications of adverse long-term effects on female reproduction following prenatal exposure to biopersistent organochlorines. These findings may have wide implications for public health as intrauterine exposure occurs worldwide.

Exposure of Female Rats to an Environmentally Relevant Mixture of Brominated Flame Retardants Targets the Ovary, Affecting Folliculogenesis and Steroidogenesis

Brominated flame retardants (BFRs) are incorporated into various consumer products to prevent flame propagation. These compounds leach into the domestic environment, resulting in chronic exposure and contamination. Pregnancy failure is associated with high levels of BFRs in human follicular fluid, raising serious questions regarding their impact on female reproductive health. The goal of this study is to elucidate the effects of an environmentally relevant BFR mixture on female rat ovarian functions (i.e., folliculogenesis and steroidogenesis). A BFR dietary mixture formulated to mimic the relative BFR congener levels in North American house dust was administered to adult female Sprague-Dawley rats from 2 to 3 wk before mating until Gestational Day 20; these diets were designed to deliver nominal doses of 0, 0.06, 20, or 60 mg/kg/day of the BFR mixture. Exposure to BFRs triggered an approximately 50% increase in the numbers of preantral and antral follicles and an enlargement of the antral follicles in the ovaries of the dams. A significant reduction in the expression of catalase, an antioxidant enzyme, and downregulation of the expression of insulin-like factor 3 (Insl3) and 17alpha-hydroxylase (Cyp17a1) were observed in the ovary. In addition, BFR exposure affected steroidogenesis; we observed a significant decrease in circulating 17-hydroxypregnenolone and an increase in testosterone concentrations in BFR-exposed dams. Thus, BFRs target ovarian function in the rat, adversely affecting both folliculogenesis and steroidogenesis.

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.

Conditional knockout of the androgen receptor in gonadotropes reveals crucial roles for androgen in gonadotropin synthesis and surge in female mice

Polycystic ovary syndrome is the major cause of infertility in reproductive aged women. Polycystic ovary syndrome is associated with high circulating levels of androgens and impaired metabolic function. The goal of this study was to understand how androgen signaling via the androgen receptor (AR) affects reproductive function. We knocked out the AR gene specifically in pituitary gonadotropes (PitARKO) to explore the role of androgen on the development of reproductive function in female mice. There was no difference in the age of puberty between control and PitARKO littermates, which was assessed by the ages of vaginal opening and first estrus. Cyclicity and fertility were also studied, and there was no significant difference between control and PitARKO mice. We observed a significant decrease in basal FSH serum and mRNA levels with no corresponding change in LH serum and mRNA levels. Although the numbers of litters born to control and PitARKO females were the same, the litter size was significantly smaller for PitARKO mice. The LH and FSH responses to ovariectomy was altered with reduced LH/FSH hormone and mRNA levels in PitARKO females. This reduction may be due to reduced expression of activin A/B and gnrhr. The preovulatory surge levels of LH and FSH were dramatically lower in PitARKO mice. The number of corpora lutea was decreased whereas the number of antral follicles was similar between control and PitARKO mice. Overall the pituitary AR contributes to the elaboration of the LH surge and normal reproductive function by regulating LH/FSH expression and secretion.

Characterization of reproductive, metabolic, and endocrine features of polycystic ovary syndrome in female hyperandrogenic mouse models

Polycystic ovary syndrome (PCOS) affects 5-10% of women of reproductive age, causing a range of reproductive, metabolic and endocrine defects including anovulation, infertility, hyperandrogenism, obesity, hyperinsulinism, and an increased risk of type 2 diabetes and cardiovascular disease. Hyperandrogenism is the most consistent feature of PCOS, but its etiology remains unknown, and ethical and logistic constraints limit definitive experimentation in humans to determine mechanisms involved. In this study, we provide the first comprehensive characterization of reproductive, endocrine, and metabolic PCOS traits in 4 distinct murine models of hyperandrogenism, comprising prenatal dihydrotestosterone (DHT, potent nonaromatizable androgen) treatment during days 16-18 of gestation, or long-term treatment (90 days from 21 days of age) with DHT, dehydroepiandrosterone (DHEA), or letrozole (aromatase inhibitor). Prenatal DHT-treated mature mice exhibited irregular estrous cycles, oligo-ovulation, reduced preantral follicle health, hepatic steatosis, and adipocyte hypertrophy, but lacked overall changes in body-fat composition. Long-term DHT treatment induced polycystic ovaries displaying unhealthy antral follicles (degenerate oocyte and/or > 10% pyknotic granulosa cells), as well as anovulation and acyclicity in mature (16-week-old) females. Long-term DHT also increased body and fat pad weights and induced adipocyte hypertrophy and hypercholesterolemia. Long-term letrozole-treated mice exhibited absent or irregular cycles, oligo-ovulation, polycystic ovaries containing hemorrhagic cysts atypical of PCOS, and displayed no metabolic features of PCOS. Long-term dehydroepiandrosterone treatment produced no PCOS features in mature mice. Our findings reveal that long-term DHT treatment replicated a breadth of ovarian, endocrine, and metabolic features of human PCOS and provides the best mouse model for experimental studies of PCOS pathogenesis.

Antenatal hypoxia induces programming of reduced arterial blood pressure response in female rat offspring: role of ovarian function

In utero exposure to adverse environmental factors increases the risk of cardiovascular disease in adulthood. The present study tested the hypothesis that antenatal hypoxia causes a gender-dependent programming of altered arterial blood pressure response (BP) in adult offspring. Time-dated pregnant rats were divided into normoxic and hypoxic (10.5% O2 from days 15 to 21 of gestation) groups. The experiments were conducted in adult offspring. Antenatal hypoxia caused intrauterine growth restriction, and resulted in a gender-dependent increase Angiotensin II (Ang II)-induced BP response in male offspring, but significant decrease in BP response in female offspring. The baroreflex sensitivity was not significantly altered. Consistent with the reduced blood pressure response, antenatal hypoxia significantly decreased Ang II-induced arterial vasoconstriction in female offspring. Ovariectomy had no significant effect in control animals, but significantly increased Ang II-induced maximal BP response in prenatally hypoxic animals and eliminated the difference of BP response between the two groups. Estrogen replacement in ovariectomized animals significantly decreased the BP response to angiotensin II I only in control, but not in hypoxic animals. The result suggests complex programming mechanisms of antenatal hypoxia in regulation of ovary function. Hypoxia-mediated ovary dysfunction results in the phenotype of reduced vascular contractility and BP response in female adult offspring.

Fetal programming of sexual development and reproductive function

The recent growth of interest in developmental programming of physiological systems has generally focused on the cardiovascular system (especially hypertension) and predisposition to metabolic dysfunction (mainly obesity and diabetes). However, it is now clear that the full range of altered offspring phenotypes includes impaired reproductive function. In rats, sheep and nonhuman primates, reproductive capacity is altered by challenges experienced during critical periods of development. This review will examine available experimental evidence across commonly studied experimental species for developmental programming of female and male reproductive function throughout an individual's life-course. It is necessary to consider events that occur during fetal development, early neonatal life and prior to and during puberty, during active reproductive life and aging as reproductive performance declines.

Regulation of baboon fetal ovarian development by placental estrogen: onset of puberty is delayed in offspring deprived of estrogen in utero

Using the baboon as a model for studies of human reproductive biology, we previously showed that placental estrogen regulates fetal ovarian follicle development. In this study, offspring of baboons untreated or treated in utero with the aromatase inhibitor letrozole (estradiol reduced >95%) or letrozole and estradiol were reared to adulthood to determine whether estrogen programming of the fetal ovary impacted puberty and reproduction in adulthood. All offspring exhibited normal growth and blood pressure/chemistries. Puberty onset in untreated baboons (43.2 ± 1.4 mo) was delayed (P < 0.01) in animals of letrozole-treated mothers (49.0 ± 1.2 mo) and normal in offspring of mothers treated with letrozole and estradiol (42.7 ± 0.8 mo). During the first 2 yr postmenarche, menstrual cycles in estrogen-suppressed animals (43.2 ± 1.3 days) were longer (P < 0.05) than in untreated baboons (38.3 ± 0.5 days) or those treated with letrozole and estrogen (39.6 ± 0.8 days). Moreover, in estrogen-suppressed offspring, serum levels of estradiol were lower and follicle-stimulating hormone greater (P < 0.05) in the follicular and luteal phases, and the elevation in luteal-phase progesterone extended (P < 0.02). Thus, puberty onset was delayed and menstrual cycles prolonged and associated with altered serum hormone levels in baboon offspring that developed in an intrauterine environment in which estradiol levels were suppressed. Because puberty and follicle development, as shown previously, were normal in baboons treated in utero with letrozole and estradiol, we propose that fetal ovarian development and timely onset of puberty in the primate is programmed by fetal exposure to placental estrogen.

Characterizing the neuroendocrine and ovarian defects of androgen receptor-knockout female mice

Homozygous androgen receptor (AR)-knockout (ARKO) female mice are subfertile due to both intra- and extraovarian (neuroendocrine) defects as defined by ovary transplantation. Using ARKO mice, this study set out to reveal the precise AR-regulated pathways required for optimal androgen-regulated ovulation and fertility. ARKO females exhibit deficient neuroendocrine negative feedback, with a reduced serum luteinizing hormone (LH) response to ovariectomy (OVX) (P < 0.01). Positive feedback is also altered as intact ARKO females, at late proestrus, exhibit an often mistimed endogenous ovulatory LH surge. Furthermore, at late proestrus, intact ARKO females display diminished preovulatory serum estradiol (E2; P < 0.01) and LH (P < 0.05) surge levels and reduced Kiss1 mRNA expression in the anteroventral periventricular nucleus (P < 0.01) compared with controls. However, this reduced ovulatory LH response in intact ARKO females can be rescued by OVX and E2 priming or treatment with endogenous GnRH. These findings reveal that AR regulates the negative feedback response to E2, E2-positive feedback is compromised in ARKO mice, and AR-regulated negative and positive steroidal feedback pathways impact on intrahypothalamic control of the kisspeptin/GnRH/LH cascade. In addition, intraovarian AR-regulated pathways controlling antral to preovulatory follicle dynamics are disrupted because adult ARKO ovaries collected at proestrus have small antral follicles with reduced oocyte/follicle diameter ratios (P < 0.01) and increased proportions of unhealthy large antral follicles (P < 0.05) compared with controls. As a consequence of aberrant follicular growth patterns, proestrus ARKO ovaries also exhibit fewer preovulatory follicle (P < 0.05) and corpora lutea numbers (P < 0.01). However, embryo development to the blastocyst stage is unchanged in ARKO females, and hence, the subfertility is a consequence of reduced ovulations and not altered embryo quality. These findings reveal that the AR has a functional role in neuroendocrine regulation and timing of the ovulatory LH surge as well as antral/preovulatory follicle development.

Targeted loss of androgen receptor signaling in murine granulosa cells of preantral and antral follicles causes female subfertility

Ovarian granulosa cells display strong androgen receptor (AR) expression, suggesting a functional role for direct AR-mediated actions within developing mammalian follicles. By crossing AR-floxed and anti-Müllerian hormone (AMH)-Cre recombinase mice, we generated granulosa cell-specific androgen receptor knockout mice (GCARKO). Cre expression, assessed by lacZ activity, localized to 70%-100% of granulosa cells in most preantral to antral follicles, allowing for selected evaluation of granulosa cell AR-dependent actions during follicle development. Relative to wild-type (WT) females, GCARKO females were subfertile, producing a 24% reduction in the number of litters (P < 0.05) over 6 mo and an age-dependent decrease in total number of pups born, evident from 6 mo of age (P < 0.05). Follicle dynamics were altered in GCARKO ovaries at 3 mo of age, with a significant reduction in large preantral and small antral follicle numbers compared to WT ovaries (P < 0.05). Global premature follicle depletion was not observed, but increased follicular atresia was evident in GCARKO ovaries at 6 mo of age, with an 81% increase in unhealthy follicles and zona pellucida remnants (P < 0.01). Cumulus cell expansion was decreased (P < 0.01) and oocyte viability was diminished in GCARKO females, with a significant reduction in the percentage of oocytes fertilized after natural mating and, thus, in the rate of progression to the two-cell embryo stage (P < 0.05). In addition, compared with age-matched WT females, 6-mo-old GCARKO females exhibited significantly prolonged estrous cycles (P ≤ 0.05), suggesting altered hypothalamic-pituitary-gonadal feedback signaling. In conclusion, our findings revealed that selective loss of granulosa cell AR actions during preantral and antral stages of development leads to a premature reduction in female fecundity through reduced follicle health and oocyte viability.

[The pathomechanism of polycystic ovary syndrome in the light of recent research findings]

The author summarizes the factors which play a role in the development of polycystic ovary syndrome highlighting the impact of intrauterine genetic programming and the importance of the maternal steroid environment. Environmental effects, steroid receptor modulators, endocrine disruptor compounds, and the role of obesity in the development of polycystic ovary syndrome are also discussed.

Temporal window in which exposure to estradiol permanently modifies ovarian function causing polycystic ovary morphology in rats

OBJECTIVE

To investigate the developmental window in which E(2) exposure produces irreversible changes in ovarian function resulting in polycystic ovary.

DESIGN

Basic experimental study.

SETTING

University animal laboratory.

ANIMAL(S)

Thirty Sprague-Dawley rats were administered a single E(2) valerate dose (10 mg/kg of weight) at 1, 7, 14, 21, or 30 days of age. Control rats were injected with the vehicle at 1 day of age. All rats were sacrificed at 6 months of age.

INTERVENTION(S)

Observation of vaginal opening, estrous cyclicity by vaginal smears, and ovarian morphometry in the 6-month-old rat.

MAIN OUTCOME MEASURE(S)

Measurement of ovarian noradrenaline by high-performance liquid chromatography coupled with electrochemical detection, serum levels of LH by enzyme-linked immunoassay, P, androstenedione, and E(2) by enzyme immunoassay.

RESULT(S)

Rats exposed to E(2) at 1, 7, or 14 days of life did not show estrual cycling activity and maintained a polycystic ovary (PCO) condition throughout the entirety of the study. However, if the exposure to E(2) occurred after postnatal day 21, the PCO-induced condition was reversible. In rats that developed a permanent PCO condition, we observed significant effects of E(2) on ovarian morphology if exposure occurred on postnatal day 1 and a presumable effect on the hypothalamus if the exposure occurred between postnatal days 1 and 14.

CONCLUSION(S)

Our findings suggest that in rats, the most sensitive period for the promotion of an irreversible PCO morphology by estrogenic compounds is during neonatal early follicular development.

Reproductive medicine and inheritance of infertility by offspring: the role of fetal programming

OBJECTIVE

To summarize the molecular processes involved in fetal programming, to describe how assisted reproduction technologies (ART) may affect the epigenetic pattern of the embryo, and to highlight the current knowledge of the role of perinatal events in the subsequent development of reproductive pathology affecting infertile patients.

DESIGN

A literature review of fetal programming of adulthood gynecologic diseases and ART. A Medline search was performed with the following keywords: (fetal programming OR epigenetics OR methylation OR acetylation) AND (IVF OR ART) AND (gynecology). Articles up to October 2010 were selected. Articles and recent reviews were classified by human and animals studies and also according to their experimental or observational design.

SETTING

University hospital research center.

PATIENT(S)

None.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

None.

RESULT(S)

Data from experimental animal models and case-control studies support the potential effect of ART in changing methylation patterns in gametes and embryos. However, these findings are not supported by population studies or experimental studies performed in human gametes/embryos. Experimental and epidemiologic studies support the hypothesis that some adult gynecologic diseases causing infertility may have a fetal origin.

CONCLUSION(S)

Although it seems clear that some adult gynecologic diseases causing infertility may have a fetal origin, there is insufficient evidence to confirm that ART is the origin of later onset, adulthood diseases. Further research in this field must be conducted.

Identification of a line of sheep carrying a putative autosomal gene increasing ovulation rate in sheep that does not appear to interact with mutations in the transforming growth factor beta superfamily

Sheep lines with mutations in single genes that have major effects on ovulation rate have been very useful in gaining a better understanding of pathways important in controlling follicular development and ovulation rate. To date however, all known mutations are in the transforming growth factor beta (TGFB) superfamily. Ovulation rates were measured in 720 progeny of 20 rams that were descendants of a single prolific ewe. Evaluation of ovulation rates of daughters of closely related sires suggests the presence of a segregating major gene Fecundity Davisdale (FECD) that increases ovulation rate between 0.4 and 0.8 in heterozygous daughters. Key features of mutations in genes of the TGFB superfamily pathway, such as synergistic interactions with other family members, infertility in homozygous carriers, and increased responsiveness to exogenous gonadotropins, were not observed in this line; thus, the mutation does not appear to be acting in the TGFB pathway. Hence, there is likely a novel mutation being carried in this line of sheep that alters ovulation rate. Future identification of the causative mutation may provide new insights into regulation of follicular development and ovulation rate.