Alterations of folliculogenesis in women with polycystic ovary syndrome

Comparison of serum levels of IL-10 and IL-11 and mRNA expression of IL-10, IL-11, COX-2, BCL6, and ZEB Family in peripheral blood mononuclear cells (PBMC) of women with polycystic ovary syndrome and healthy individuals

BACKGROUND

The roles of IL-10, IL-11, COX-2, BCL6, ZEB1, and ZEB2 genes in the potential correlation between polycystic ovary syndrome (PCOS), inflammation, and cancer remain controversial.

AIMS

This study aimed to compare serum levels of IL-10 and IL-11 and gene expression of IL-10, IL-11, COX-2, BCL6, ZEB1, and ZEB2 in PBMCs of women with PCOS and healthy controls.

METHODS

A case-control study included 40 women with PCOS as the case group and 40 healthy women as controls. Group matching for age and BMI was performed. Serum levels of IL-10 and IL-11 were assessed using ELISA, while gene expression was measured using real-time PCR. Parameters were compared between groups, and correlations among gene expression and serum levels were explored.

RESULTS

In comparison to healthy women, women with PCOS exhibited a significant decrease in the expression of COX-2 and IL-10 genes (p<0.001), alongside a significant increase in ZEB2 gene expression (p<0.001). There were no significant differences observed in the expression of IL-11, BCL6, and ZEB1 genes. Furthermore, the serum level of IL-10 was significantly lower in women with PCOS compared to the control group (p<0.001), while no significant difference was found in IL-11 levels. Additionally, no significant correlations were identified between gene expression and serum levels.

CONCLUSION

In women with PCOS, reduced IL-10 gene expression may indicate inflammation and serve as a diagnostic biomarker. However, conflicting findings on COX-2 expression complicate understanding. Elevated ZEB2 expression in PCOS women may lead to infertility, epithelial-mesenchymal transition, and aggressive phenotypes.

Induced Pluripotent Stem Cells as a Possible Approach for Exploring the Pathophysiology of Polycystic Ovary Syndrome (PCOS)

Polycystic ovary syndrome (PCOS) is the most prevalent endocrine condition among women with pleiotropic sequelae possessing reproductive, metabolic, and psychological characteristics. Although the exact origin of PCOS is elusive, it is known to be a complex multigenic disorder with a genetic, epigenetic, and environmental background. However, the pathogenesis of PCOS, and the role of genetic variants in increasing the risk of the condition, are still unknown due to the lack of an appropriate study model. Since the debut of induced pluripotent stem cell (iPSC) technology, the ability of reprogrammed somatic cells to self-renew and their potential for multidirectional differentiation have made them excellent tools to study different disease mechanisms. Recently, researchers have succeeded in establishing human in vitro PCOS disease models utilizing iPSC lines from heterogeneous PCOS patient groups (iPSCPCOS). The current review sets out to summarize, for the first time, our current knowledge of the implications and challenges of iPSC technology in comprehending PCOS pathogenesis and tissue-specific disease mechanisms. Additionally, we suggest that the analysis of polygenic risk prediction based on genome-wide association studies (GWAS) could, theoretically, be utilized when creating iPSC lines as an additional research tool to identify women who are genetically susceptible to PCOS. Taken together, iPSCPCOS may provide a new paradigm for the exploration of PCOS tissue-specific disease mechanisms.

A comprehensive review on the impact of calcium and vitamin D insufficiency and allied metabolic disorders in females

Calcium is imperative in maintaining a quality life, particularly during later ages. Its deficiency results in a wide range of metabolic disorders such as dental changes, cataracts, alterations in brain function, and osteoporosis. These deficiencies are more pronounced in females due to increased calcium turnover throughout their life cycle, especially during pregnancy and lactation. Vitamin D perform a central role in the metabolism of calcium. Recent scientific interventions have linked calcium with an array of metabolic disorders in females including hypertension, obesity, premenstrual dysphoric disorder, polycystic ovary syndrome (PCOS), multiple sclerosis, and breast cancer. This review encompasses these female metabolic disorders with special reference to calcium and vitamin D deficiency. This review article aims to present and elaborate on available data regarding the worldwide occurrence of insufficient calcium consumption in females and allied health risks, to provide a basis for formulating strategies and population-level scientific studies to adequately boost calcium intake and position where required.

Current Advances in Cellular Approaches for Pathophysiology and Treatment of Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a prevalent gynecological and endocrine disorder that results in irregular menstruation, incomplete follicular development, disrupted ovulation, and reduced fertility rates among affected women of reproductive age. While these symptoms can be managed through appropriate medication and lifestyle interventions, both etiology and treatment options remain limited. Here we provide a comprehensive overview of the latest advancements in cellular approaches utilized for investigating the pathophysiology of PCOS through in vitro cell models, to avoid the confounding systemic effects such as in vitro fertilization (IVF) therapy. The primary objective is to enhance the understanding of abnormalities in PCOS-associated folliculogenesis, particularly focusing on the aberrant roles of granulosa cells and other relevant cell types. Furthermore, this article encompasses analyses of the mechanisms and signaling pathways, microRNA expression and target genes altered in PCOS, and explores the pharmacological approaches considered as potential treatments. By summarizing the aforementioned key findings, this article not only allows us to appreciate the value of using in vitro cell models, but also provides guidance for selecting suitable research models to facilitate the identification of potential treatments and understand the pathophysiology of PCOS at the cellular level.

Androgen signalling in the ovaries and endometrium

Currently, our understanding of hormonal regulation within the female reproductive system is largely based on our knowledge of estrogen and progesterone signalling. However, while the important functions of androgens in male physiology are well known, it is also recognized that androgens play critical roles in the female reproductive system. Further, androgen signalling is altered in a variety of gynaecological conditions, including endometriosis and polycystic ovary syndrome, indicative of regulatory roles in endometrial and ovarian function. Co-regulatory mechanisms exist between different androgens, estrogens, and progesterone, resulting in a complex network of steroid hormone interactions. Evidence from animal knockout studies, in vitro experiments, and human data indicate that androgen receptor expression is cell-specific and menstrual cycle stage-dependent, with important regulatory roles in the menstrual cycle, endometrial biology, and follicular development in the ovaries. This review will discuss the expression and co-regulatory interactions of androgen receptors, highlighting the complexity of the androgen signalling pathway in the endometrium and ovaries, and the synthesis of androgens from additional alternative pathways previously disregarded as male-specific. Moreover, it will illustrate the challenges faced when studying androgens in female biology, and the need for a more in-depth, integrative view of androgen metabolism and signalling in the female reproductive system.

The molecular mechanism of miR-96-5p in the pathogenesis and treatment of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS), characterized by the androgen excess and arrest of antral follicles, is a common endocrine disorder among women lacking specific diagnostic biomarkers and therapeutic targets. Herein, we studied the molecular mechanism of miR-96-5p in the process of PCOS and its potential applications in PCOS. Clinically, we found that miR-96-5p significantly decreased in serum, follicular fluid and primary human granulosa cells (hGCs) of PCOS patients (n = 70) vs non-PCOS women (n = 60), as well as in the ovaries of 3-types of induced PCOS-like mice. Furthermore, we demonstrated that the elevated circulating miR-96-5p levels were significantly correlated with the PCOS disordered endocrine clinical features, and the area under the curve of receiver operating characteristic was 0.8344, with 75.71% specificity and 80% sensitivity. Mechanically, we identified miR-96-5p as an androgen-regulated miRNA that directly targets the forkhead transcription factor FOXO1. Inhibition of miR-96-5p decreased estrogen synthesis, while decreasing the cell proliferation index of KGN via regulating the expression of FOXO1 and its downstream genes. Inversely, inhibition of FOXO1 abrogated the effect of miR-96-5p on estrogen synthesis and proliferation index. Of note, ovarian intra-bursal injection of miR-96-5p agomir rescued the phenotypes of dehydroepiandrosterone-induced PCOS like mice. In conclusion, our results clarified a vital role of miR-96-5p in the pathogenesis of PCOS and might serve as a novel diagnostic biomarker and therapeutic target for PCOS.

Kelulut Honey Improves Folliculogenesis, Steroidogenic, and Aromatase Enzyme Profiles and Ovarian Histomorphology in Letrozole-Induced Polycystic Ovary Syndrome Rats

Polycystic ovary syndrome (PCOS) has been linked to aberrant folliculogenesis and abnormalities in the aromatase enzyme (Cyp19a1) and the steroidogenic enzyme, 17-alpha-hydroxylase (Cyp17a1) expression. It has been demonstrated that Kelulut honey (KH) improves both female and male reproductive system anomalies in animal studies. Here, we examined the effects of isolated and combined KH, metformin, and clomiphene in improving folliculogenesis, aromatase, and steroidogenic enzyme profiles and ovarian histomorphology in letrozole-induced PCOS rats. Letrozole (1 mg/kg/day) was administered to female Sprague-Dawley (SD) rats for 21 days to induce PCOS. PCOS rats were subsequently divided into six experimental groups: untreated, treatment with metformin (500 mg/kg/day), clomiphene (2 mg/kg/day), KH (1 g/kg/day), combined KH (1 g/kg/day) and metformin (500 mg/kg/day), and combined KH (1 g/kg/day) and clomiphene (2 mg/kg/day). All treatments were given orally for 35 days. We found that KH was comparable with clomiphene and metformin in improving the expression of Cyp17a1 and Cyp19a1, apart from enhancing folliculogenesis both histologically and through the expression of folliculogenesis-related genes. Besides, the combination of KH with clomiphene was the most effective treatment in improving the ovarian histomorphology of PCOS rats. The effectiveness of KH in restoring altered folliculogenesis, steroidogenic, and aromatase enzyme profiles in PCOS warrants a future clinical trial to validate its therapeutic effect clinically.

Hyperandrogenism and Polycystic ovary syndrome: Effects in pregnancy and offspring development

Polycystic ovary syndrome (PCOS) is one of the major endocrine disorders affecting women of reproductive age. Its etiology remains unclear. It is suggested that environmental factors, and particularly the intrauterine environment, play key roles in PCOS development. Besides the role of androgens in PCOS pathogenesis, exposure to endocrine disruptors, as is Bisphenol A, could also contribute to its development. Although PCOS is considered one of the leading causes of ovarian infertility, many PCOS patients can get pregnant. Some of them by natural conception and others by assisted reproductive technique treatments. As hyperandrogenism (one of PCOS main features) affects ovarian and uterine functions, PCOS women, despite reaching pregnancy, could present high-risk pregnancies, including implantation failure, an increased risk of gestational diabetes, preeclampsia, and preterm birth. Moreover, hyperandrogenism may also be maintained in these women during pregnancy. Therefore, as an altered uterine milieu, including hormonal imbalance, could affect the developing organisms, monitoring these patients throughout pregnancy and their offspring development is highly relevant. The present review focuses on the impact of androgenism and PCOS on fertility issues and pregnancy-related outcomes and offspring development. The evidence suggests that the increased risk of pregnancy complications and adverse offspring outcomes of PCOS women would be due to the factors involved in the syndrome pathogenesis and the related co-morbidities. A better understanding of the involved mechanisms is still needed and could contribute to a better management of these women and their offspring. This article is categorized under: Reproductive System Diseases > Molecular and Cellular Physiology Reproductive System Diseases > Environmental Factors.

Letrozole-Induced Polycystic Ovary Syndrome Attenuates Cystathionine-β Synthase mRNA and Protein Abundance in the Ovaries of Female Sprague Dawley Rats

BACKGROUND

Polycystic ovary syndrome (PCOS) is an endocrine disorder that affects 10% of reproductive-aged women and leads to hyperandrogenism, anovulation, and infertility. PCOS has been associated with elevated serum homocysteine as well as altered methylation status; however, characterization of one-carbon metabolism (OCM) in PCOS remains incomplete.

OBJECTIVES

The aim of our research was to assess OCM in a letrozole-induced Sprague Dawley rat model of PCOS.

METHODS

Five-week-old female rats (n = 36) were randomly assigned to letrozole [0.9 mg/kg body weight (BW)] treatment or vehicle (carboxymethylcellulose) control that was administered via subcutaneously implanted slow-release pellets every 30 d. For both treatment groups, 12 rats were randomly assigned to be euthanized during proestrus at one of the following time points: 8, 16, or 24 wk of age. Daily BW was measured and estrous cyclicity was monitored during the last 30 d of the experimental period. Ovaries were collected to assess mRNA and protein abundance of OCM enzymes.

RESULTS

Letrozole-induced rats exhibited 1.9-fold higher cumulative BW gain compared with control rats across all age groups (P < 0.0001). Letrozole reduced the time spent at proestrus (P = 0.0001) and increased time in metestrus (P < 0.0001) of the estrous cycle. Cystathionine β-synthase (Cbs) mRNA abundance was reduced in the letrozole-induced rats at 16 (59%; P < 0.05) and 24 (77%; P < 0.01) wk of age. In addition, CBS protein abundance was 32% lower in 8-wk-old letrozole-induced rats (P = 0.02). Interestingly, betaine-homocysteine S-methyltransferase mRNA abundance increased as a function of age in letrozole-induced rats (P = 0.03).

CONCLUSION

These data demonstrate that letrozole-induced PCOS Sprague Dawley rats temporally decrease the ovarian abundance of Cbs mRNA and protein in the early stages of PCOS.

Role of adipokines in the ovarian function: Oogenesis and steroidogenesis

Adipokines are mainly produced by adipose tissue; however, their expression has been reported in other organs including female reproductive tissues. Therefore, adipokines have opened new avenues of research in female fertility. In this regard, studies reported different roles for certain adipokines in ovarian function, although the role of other recently identified adipokines is still controversial. It seems that adipokines are essential for normal ovarian function and their abnormal levels could be associated with ovarian-related disorders. The objective of this study is to review the available information regarding the role of adipokines in ovarian functions including follicular development, oogenesis and steroidogenesis and also their involvement in ovary-related disorders.

Steroid Metabolism in Children and Adolescents With Obesity and Insulin Resistance: Altered SRD5A and 20α/20βHSD Activity

Alterations in glucocorticoid metabolism may contribute to the development of obesity and insulin resistance (IR). Obesity in turn affects the androgen balance. The peripheral metabolism of steroids is equally an important determinant of their bioavailability and activity. The aim of this study was to evaluate steroid metabolism in obese children and to define which enzyme alterations are associated with IR. Clinical characteristics and anthropometric measurements were determined in 122 obese children and adolescents (72 girls, 50 boys) aged 8 - 18 years. 26 of them (21.3%) were diagnosed with IR (13 boys, 13 girls). Routine laboratory tests were performed and 24h urinary steroid excretion profiles were analyzed by gas chromatography/mass spectrometry. Positive relationship between 5α-reductase (SRD5A) activity and IR was found. According to the androsterone to etiocholanolone (An/Et) ratio the activity of SRD5A was significantly increased in obese children with IR, but the difference remained insignificant once the 5α-dihydrotestosterone to testosterone (5αDHT/T) ratio was considered. Furthermore, this relationship persisted in boys but was not observed in girls. The activity of 20α-hydroxysteroid dehydrogenase (20αHSD) and 20β-hydroxysteroid dehydrogenase (20βHSD) was reduced only in obese girls with IR. Conclude, in the context of obese children and adolescents with IR, we surmise that increased SRD5A represents a compensatory mechanism to reduce local glucocorticoid availability. This phenomenon is probably different in the liver (restriction) and in the adipose tissue (expected increase in activity). We show significant changes in 20αHSD and 20βHSD activity in obese girls with IR, but it is difficult to clearly determine whether the activity of these enzymes is an indicator of the function in their ovaries or adrenal glands.

Decreased microRNA-125b-5p disrupts follicle steroidogenesis through targeting PAK3/ERK1/2 signalling in mouse preantral follicles

BACKGROUND

Hyperandrogenism is one of the major characteristics of polycystic ovary syndrome (PCOS). Abnormal miR-125b-5p expression has been documented in multiple diseases, but whether miR-125b-5p is associated with aberrant steroidogenesis in preantral follicles remains unknown.

METHODS

Steriod hormone concentrations and miR-125b-5p expression were measured in clinical serum samples from PCOS patients. Using a mouse preantral follicle culture model and a letrozole-induced PCOS mouse model, we investigated the mechanism underlying miR-125b-5p regulation of androgen and oestrogen secretion.

RESULTS

The decreased miR-125b-5p expression was observed in the sera from hyperandrogenic PCOS (HA-PCOS) patients. In mouse preantral follicles, inhibiting miR-125b-5p increased the expression of androgen synthesis-related genes and stimulated the secretion of testosterone, while simultaneously downregulating oestrogen synthesis-related genes and decreasing oestradiol release. Ectopically expressed miR-125b-5p reversed the effects on steroidogenesis-related gene expression and hormone release. Mechanistic studies identified Pak3 as a direct target of miR-125b-5p. Furthermore, inhibiting miR-125b-5p facilitated the activation of ERK1/2 in mouse preantral follicles, while inhibiting Pak3 abrogated this activating effect. These results were recapitulated in letrozole-induced PCOS mouse ovaries. Of note, inhibiting PAK3 antagonised the positive effect of miR-125b-5p siRNA on the expressions of androgen synthesis-related enzymes and testosterone secretion. Luteinizing hormone (LH) inhibited miR-125b-5p expression, and stimulated Pak3 expression.

CONCLUSION

High serum LH concentrations in PCOS patients repress miR-125b-5p expression, which further increases Pak3 expression, leading to activation of ERK1/2 signalling, thus stimulating the expression of androgen synthesis-related enzymes and testosterone secretion in HA-PCOS.

Alterations of polyunsaturated fatty acid metabolism in ovarian tissues of polycystic ovary syndrome rats

The metabolism of polyunsaturated fatty acids (PUFAs) remains poorly characterized in ovarian tissues of patients with polycystic ovary syndrome (PCOS). This study aimed to explore alterations in the levels of PUFAs and their metabolites in serum and ovarian tissues in a PCOS rat model treated with a high‐fat diet and andronate. Levels of PUFAs and their metabolites were measured using gas/liquid chromatography‐mass spectrometry after the establishment of a PCOS rat model. Only 3 kinds of PUFAs [linoleic acid, arachidonic acid (AA) and docosahexaenoic acid] were detected in both the circulation and ovarian tissues of the rats, and their concentrations were lower in ovarian tissues than in serum. Moreover, significant differences in the ovarian levels of AA were observed between control, high‐fat diet‐fed and PCOS rats. The levels of prostaglandins, AA metabolites via the cyclooxygenase (COX) pathway, in ovarian tissues of the PCOS group were significantly increased compared to those in the controls. Further studies on the mechanism underlying this phenomenon showed a correlation between decreased expression of phosphorylated cytosolic phospholipase A2 (p‐cPLA2) and increased mRNA and protein expression of COX2, potentially leading to a deeper understanding of altered AA and prostaglandin levels in ovarian tissues of PCOS rats.

Expression of the genes for peroxisome proliferator-activated receptor-γ, cyclooxygenase-2, and proinflammatory cytokines in granulosa cells from women with polycystic ovary syndrome

Objective

To identify differences in the expression of the genes for peroxisome proliferator-activated receptor (PPAR)-γ, cyclooxygenase (COX)-2, and the proinflammatory cytokines interleukin (IL)-6 and tumor necrosis factor (TNF)-α in granulosa cells (GCs) from polycystic ovary syndrome (PCOS) patients and controls undergoing controlled ovarian stimulation.

Methods

Nine patients with PCOS and six controls were enrolled in this study. On the day of oocyte retrieval, GCs were collected from pooled follicular fluid. Total mRNA was extracted from GCs. Reverse transcription was performed and gene expression levels were quantified by realtime quantitative polymerase chain reaction.

Results

There were no significant differences in age, body mass index, and total gonadotropin dose, except for the ratio of luteinizing hormone to follicle-stimulating hormone between the PCOS and control groups. PPAR-γ and COX-2 mRNA was significantly downregulated in the GCs of PCOS women compared with controls (p=0.034 and p=0.018, respectively), but the expression of IL-6 and TNF-α mRNA did not show significant differences. No significant correlation was detected between the expression of these mRNA sequences and clinical characteristics, including the number of retrieved oocytes, oocyte maturity, cleavage, or the good embryo rate. Positive correlations were found among the PPAR-γ, COX-2, IL-6, and TNF-α mRNA levels.

Conclusion

Our data may provide novel clues regarding ovarian GC dysfunction in PCOS, and indirectly provide evidence that the effect of PPAR-γ agonists in PCOS might result from alterations in the ovarian follicular environment. Further studies with a larger sample size are required to confirm these proposals.

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.

Correlation of Vitamin D with metabolic parameters in polycystic ovarian syndrome

BACKGROUND

Polycystic ovarian syndrome (PCOS) and hypovitaminosis D are the two most common endocrine disorders in young women leading to many adverse metabolic consequences. We evaluated the correlation of 25-hydroxy Vitamin D (25OHD) with metabolic parameters and insulin resistance in PCOS.

MATERIALS AND METHODS

We included 100 PCOS patients (age 18-40 years, duration >6 months) serially, in this cross-sectional study. We excluded patients with past use of insulin sensitizers and hormone therapy. All patients underwent a physical examination, body fat estimation, and a single fasting blood sample was analyzed for the biochemical parameters. The patients were divided into 2 groups as per the 25OHD level: Group 1 (Deficient, <30 ng/mL) and Group 2 (normal). The data were analyzed using appropriate statistical methods, and a P < 0.05 was considered statistically significant.

RESULTS

The study population had a mean age of 28.6 ± 6.3 years, body mass index (BMI) 30.4 ± 6.1 kg/m² and body fat of 39.1 ± 13%. A total of 90 women had 25OHD deficiency, and hypovitaminosis D was observed more in younger, obese patients. Patients with hypovitaminosis D had a higher BMI (P = 0.0124), low- high-density lipoprotein (P = 0.0094), calcium (P ≤ 0.0001), and elevated testosterone (P = 0.0412) in comparison with normal 25OHD patients. None of the metabolic parameters showed significant correlation with 25OHD (P > 0.05).

CONCLUSION

Hypovitaminosis D is very common in PCOS patients and exacerbates the metabolic abnormalities. It is essential to screen all the PCOS patients for 25OHD deficiency, and further large-scale studies are required to confirm our findings.

Relationship between Advanced Glycation End Products and Steroidogenesis in PCOS

BACKGROUND

Women with PCOS have elevated levels of the harmful Advanced Glycation End Products (AGEs), which are highly reactive molecules formed after glycation of lipids and proteins. Additionally, AGEs accumulate in the ovaries of women with PCOS potentially contributing to the well-documented abnormal steroidogenesis and folliculogenesis.

MAIN BODY

A systematic review of articles and abstracts available in PubMed was conducted and presented in a systemic manner. This article reports changes in steroidogenic enzyme activity in granulosa and theca cells in PCOS and PCOS-models. It also described the changes in AGEs and their receptors in the ovaries of women with PCOS and presents the underlying mechanism(s) whereby AGEs could be responsible for the PCOS-related changes in granulosa and theca cell function thus adversely impacting steroidogenesis and follicular development. AGEs are associated with hyperandrogenism in PCOS possibly by altering the activity of various enzymes such as cholesterol side-chain cleavage enzyme cytochrome P450, steroidogenic acute regulatory protein, 17α-hydroxylase, and 3β-hydroxysteroid dehydrogenase. AGEs also affect luteinizing hormone receptor and anti-Mullerian hormone receptor expression as well as their signaling pathways in granulosa cells.

CONCLUSIONS

A better understanding of how AGEs alter granulosa and theca cell function is likely to contribute meaningfully to a conceptual framework whereby new interventions to prevent and/or treat ovarian dysfunction in PCOS can ultimately be developed.

Physiological Aspects of Female Fertility: Role of the Environment, Modern Lifestyle, and Genetics

Across the Western World there is an increasing trend to postpone childbearing. Consequently, the negative influence of age on oocyte quality may lead to a difficulty in conceiving for many couples. Furthermore, lifestyle factors may exacerbate a couple's difficulty in conceiving due mainly to the metabolic influence of obesity; however, the negative impacts of low peripheral body fat, excessive exercise, the increasing prevalence of sexually transmitted diseases, and smoking all have significant negative effects on fertility. Other factors that impede conception are the perceived increasing prevalence of the polycystic ovary syndrome, which is further exacerbated by obesity, and the presence of uterine fibroids and endometriosis (a progressive pelvic inflammatory disorder) which are more prevalent in older women. A tendency for an earlier sexual debut and to have more sexual partners has led to an increase in sexually transmitted diseases. In addition, there are several genetic influences that may limit the number of oocytes within the ovary; consequently, by postponing attempts at childbearing, a limitation of oocyte number may become evident, whereas in previous generations with earlier conception this potentially reduced reproductive life span did not manifest in infertility. Environmental influences on reproduction are under increasing scrutiny. Although firm evidence is lacking however, dioxin exposure may be linked to endometriosis, phthalate exposure may influence ovarian reserve, and bisphenol A may interfere with oocyte development and maturation. However, chemotherapy or radiotherapy is recognized to lead to ovarian damage and predispose the woman to ovarian failure.

Cortisol-Metabolizing Enzymes in Polycystic Ovary Syndrome

OBJECTIVE

The aim of this study was to assess the activity of cortisol-metabolizing enzymes in women with polycystic ovary syndrome (PCOS), using a fully quantitative gas chromatography/mass spectrometry (GCMS) method.

DESIGN

We investigated the glucocorticoid degradation pathways that include 11β-hydroxysteroid dehydrogenase (11β-HSD) type 1, 5α-reductase (5α-R) and 5β-reductase (5β-R), 3α-hydroxysteroid dehydrogenase, and 20α- and 20β-hydroxysteroid dehydrogenase (20α-HSD and 20β-HSD, respectively) in young nonobese women with PCOS, using a fully quantitative GCMS method.

SETTING

This study was conducted in a tertiary referral hospital in Israel.

PATIENTS

This study group consisted of 13 young women, aged 20.1 ± 2.8 years (mean ± SD), with the body mass index (BMI) of 22.6 ± 3.7 kg/m², diagnosed with PCOS according to the Rotterdam criteria. The control group consisted of 14 healthy young women matched for weight, height, and BMI.

INTERVENTIONS

Urine samples were analyzed using GCMS. We measured urinary steroid metabolites that represent the products and substrates of the study enzymes and calculated the product/substrate ratios to represent enzyme activity.

MAIN OUTCOME MEASURES

The calculation of enzymatic activity, based on glucocorticoid degradation metabolites, was done by GCMS in PCOS vs. controls.

RESULTS

All glucocorticoid degradation metabolites were higher in the PCOS group than in controls. Of the adrenal enzymes, the activities of 21-hydroxylase and 17α-hydroxylase were reduced, whereas the activity of 17,20-lyase was enhanced in PCOS. Of the degradation enzymes, the activity of 11β-HSD type 1 was reduced in women with PCOS only when calculated from cortoles and cortolones ratios. The activities of 5α-R/5β-R were increased only when calculating the 11-hydroxy metabolites of androgens. The activity of 20α-HSD was elevated in the patients with PCOS and its relation with the substrate levels was lost.

CONCLUSIONS

We confirm PCOS association with low 21-hydroxylase activity. PCOS is associated with dysregulation in glucocorticoid degradation. The activity of 5α-R is enhanced only through the backdoor pathway. Marked increase in the activity of 20α-HSD suggests a hitherto unknown derangement in PCOS.

Genome-wide association of polycystic ovary syndrome implicates alterations in gonadotropin secretion in European ancestry populations

Polycystic ovary syndrome (PCOS) is a common, highly heritable complex disorder of unknown aetiology characterized by hyperandrogenism, chronic anovulation and defects in glucose homeostasis. Increased luteinizing hormone relative to follicle-stimulating hormone secretion, insulin resistance and developmental exposure to androgens are hypothesized to play a causal role in PCOS. Here we map common genetic susceptibility loci in European ancestry women for the National Institutes of Health PCOS phenotype, which confers the highest risk for metabolic morbidities, as well as reproductive hormone levels. Three loci reach genome-wide significance in the case–control meta-analysis, two novel loci mapping to chr 8p32.1 and chr 11p14.1, and a chr 9q22.32 locus previously found in Chinese PCOS. The same chr 11p14.1 SNP, rs11031006, in the region of the follicle-stimulating hormone B polypeptide (FSHB) gene strongly associates with PCOS diagnosis and luteinizing hormone levels. These findings implicate neuroendocrine changes in disease pathogenesis.

Polycystic Ovary Sydrome is a highly heritable, complex reproductive disorder with unknown underlying genetic factors. Here Hayes and Urbanek et al. identify three loci in European women strongly associated with neuroendocrine changes and disease susceptibility.

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.

Effect of glucocorticoid-induced insulin resistance on follicle development and ovulation

Polycystic ovarian syndrome (PCOS) is characterized by hyperandrogenemia, polycystic ovaries, and menstrual disturbance and a clear association with insulin resistance. This research evaluated whether induction of insulin resistance, using dexamethasone (DEX), in a monovular animal model, the cow, could produce an ovarian phenotype similar to PCOS. In all of these experiments, DEX induced insulin resistance in cows as shown by increased glucose, insulin, and HOMA-IR (homeostasis model assessment of insulin resistance). Experiment 1: DEX induced anovulation (zero of five DEX vs. four of four control cows ovulated) and decreased circulating estradiol (E2). Experiment 2: Gonadotropin-releasing hormone (GnRH) was administered to determine pituitary and follicular responses during insulin resistance. GnRH induced a luteinizing hormone (LH) surge and ovulation in both DEX (seven of seven) and control (seven of seven) cows. Experiment 3: E2 was administered to determine hypothalamic responsiveness after induction of an E2 surge in DEX (eight of eight) and control (eight of eight) cows. An LH surge was induced in control (eight of eight) but not DEX (zero of eight) cows. All control (eight of eight) but only two of eight DEX cows ovulated within 60 h of E2 administration. Experiment 4: Short-term DEX was initiated 24 h after induced luteal regression to determine if DEX could acutely block ovulation before peak insulin resistance was induced, similar to progesterone (P4). All control (five of five), no P4-treated (zero of six), and 50% of DEX-treated (three of six) cows ovulated by 96 h after luteal regression. All anovular cows had reduced circulating E2. These data are consistent with DEX creating a lesion in hypothalamic positive feedback to E2 without altering pituitary responsiveness to GnRH or ovulatory responsiveness of follicles to LH. It remains to be determined if the considerable insulin resistance and the reduced follicular E2 production induced by DEX had any physiological importance in the induction of anovulation.

Vitamin D in the aetiology and management of polycystic ovary syndrome

Vitamin D deficiency is common in women with polycystic ovary syndrome (PCOS), with the 67-85% of women with PCOS having serum concentrations of 25-hydroxy vitamin D (25OHD) <20 ng/ml. Vitamin D deficiency may exacerbate symptoms of PCOS, with observational studies showing lower 25OHD levels were associated with insulin resistance, ovulatory and menstrual irregularities, lower pregnancy success, hirsutism, hyperandrogenism, obesity and elevated cardiovascular disease risk factors. There is some, but limited, evidence for beneficial effects of vitamin D supplementation on menstrual dysfunction and insulin resistance in women with PCOS. Vitamin D deficiency may play a role in exacerbating PCOS, and there may be a place for vitamin D supplementation in the management of this syndrome, but current evidence is limited and additional randomized controlled trials are required to confirm the potential benefits of vitamin D supplementation in this population.

Altered endothelin expression in granulosa-lutein cells of women with polycystic ovary syndrome

AIMS

To examine the levels of endothelin system components in granulosa lutein cells (GLCs) of women with PCOS and compare them to normally ovulating women undergoing In Vitro Fertilization (IVF). Polycystic ovary syndrome (PCOS) is one of the most common endocrine-metabolic disorders in women of reproductive age. Endothelins are locally produced by endothelial and granulosa cells of the preovulatory follicle. Abnormal expression or production of endothelins may be a contributing factor in PCOS pathogenesis.

MAIN METHODS

Follicular aspirates containing GLCs were obtained from PCOS and normally ovulating patients undergoing oocyte retrieval during the IVF cycle. RNA was extracted and endothelin system components were quantified using real-time PCR. GLCs were cultured in basal media for 7 days, and then challenged with various luteinizing agents (luteinizing hormone, hCG, or forskolin) for 24 h.

KEY FINDINGS

In GLCs from women with PCOS, Endothelin-1 mRNA expression was elevated (2.2-fold) as compared with normally ovulating women, whereas endothelin-2 mRNA was reduced (1.8-fold). ET receptors and endothelin-converting enzyme showed the same expression levels in the two groups. In vitro modeling showed that although the steroidogenic response was preserved in GLC, endothelin expression levels were not exhibited in vitro in their original pattern.

SIGNIFICANCE

Dysregulation of ovarian endothelin expression may induce a pathologic ovulation pattern characteristic of PCOS.