Adipocyte dysfunction in a mouse model of polycystic ovary syndrome (PCOS): evidence of adipocyte hypertrophy and tissue-specific inflammation

Rodent models in polycystic ovarian Syndrome: Dissecting reproductive and metabolic phenotypes for therapeutic Advancements

The most prevalent reason for female infertility is polycystic ovarian syndrome (PCOS) exhibiting two of three phenotypes including biochemical or clinical hyperandrogenism, anovulation and polycystic ovaries. Insulin resistance and obesity are common in PCOS-afflicted women. Androgens are thought to be the primary cause of PCOS causing symptoms including anovulation, follicles that resemble cysts, higher levels of the luteinizing hormone (LH), increased adiposity, and insulin resistance. However, due to the heterogeneity of PCOS, it is challenging to establish a single model that accurately mimics all the reproductive and metabolic phenotypes seen in PCOS patients. In this review, we aimed to investigate rodent models of PCOS and related phenotypes with or without direct hormonal treatments and to determine the underlying mechanisms to comprehend PCOS better. We summarized rodent models of PCOS that includes direct and indirect hormone intervention and discussed the aetiology of PCOS and related phenotypes produced in rodent models. We presented combined insights on multiple rodent models of PCOS and compared their reproductive and/or metabolic phenotypes. Our review indicates that there are various models for studying PCOS and one should select a model most suitable for their purpose. This review will be helpful for consideration of rodent models for PCOS which are not conventionally used to determine mechanisms at the molecular/cellular levels encouraging development of novel treatments and control methods for PCOS.

MicroRNA-21 modulates brown adipose tissue adipogenesis and thermogenesis in a mouse model of polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS), the most common endocrine disorder in premenopausal women, is associated with increased obesity, hyperandrogenism, and altered brown adipose tissue (BAT) thermogenesis. MicroRNAs play critical functions in brown adipocyte differentiation and maintenance. We aim to study the role of microRNA-21 (miR-21) in altered energy homeostasis and BAT thermogenesis in a PCOS mouse model of peripubertal androgen exposure.

METHODS

Three-week-old miR-21 knockout (miR21KO) or wild-type (WT) female mice were treated with dihydrotestosterone (DHT) or vehicle for 90 days. Body composition was determined by EchoMRI. Energy expenditure (EE), oxygen consumption (VO2), carbon dioxide production (VCO2), and respiratory exchange ratio (RER) were measured by indirect calorimetry. Androgen receptor (AR), and markers of adipogenesis, de novo lipogenesis, angiogenesis, extracellular matrix remodeling, and thermogenesis were quantified by RT-qPCR and/or Western-blot.

RESULTS

MiR-21 ablation attenuated DHT-mediated increase in body weight while having no effect on fat or BAT mass. MiR-21 ablation attenuated DHT-mediated BAT AR upregulation. MiR-21 ablation did not alter EE; however, miR21KO DHT-treated mice have reduced VO2, VCO2, and RER. MiR-21 ablation reversed DHT-mediated decrease in food intake and increase in sleep time. MiR-21 ablation decreased some adipogenesis (Adipoq, Pparγ, and Cebpβ) and extracellular matrix remodeling (Mmp-9 and Timp-1) markers expression in DHT-treated mice. MiR-21 ablation abolished DHT-mediated increases in thermogenesis markers Cpt1a and Cpt1b, while decreasing CIDE-A expression.

CONCLUSIONS

Our findings suggest that BAT miR-21 may play a role in regulating DHT-mediated thermogenic dysfunction in PCOS. Modulation of BAT miR-21 levels could be a novel therapeutic approach for the treatment of PCOS-associated metabolic derangements.

Alleviation of adipose-hepatic glycolipid dysregulation by acetate in experimental PCOS model is associated with NF-κB/NLRP3 repression

This study hypothesized that acetate breaks the vicious cycle driving adipose-hepatic metabolic dysregulation in a rat model of polycystic ovarian syndrome (PCOS), possibly by suppression of nuclear factor-kappaB (NF-κB)/NOD-like receptor protein 3 (NLRP3) inflammasome. Female Wistar rats (8-week-old) were randomly allocated into four groups of n =6/group, which received vehicle, sodium acetate (200 mg), letrozole (1 mg/kg), and letrozole plus sodium acetate, respectively. The animals were treated by oral gavage, once daily for a period of 21 days. The PCOS animals were insulin-resistant, hyperandrogenic, and hypoestrogenic with decreased sex-hormone binding globulin. In addition, the hepatic tissue had increased lipid profile and decreased glycogen synthesis, while the adipose tissue showed decreased lipid profile with elevated glycogen synthesis. Besides, the results also showed increased malondialdehyde, γ-glutamyl transferase, lactate dehydrogenase, and inflammatory mediators with corresponding decrease in antioxidant defense in the hepatic and adipose tissues. Immunohistochemical evaluation also demonstrated severe expression with Bcl2-associated X protein/NLRP3 antibodies. Nonetheless, concomitant acetate supplementation attenuated these derangements. The present data collectively suggest that acetate ameliorates adipose-hepatic glycolipid dysregulation in experimental PCOS model by attenuating androgen excess and NF-κB/NLRP3 immunoreactivity.

Updated experimental cellular models to study polycystic ovarian syndrome

Polycystic ovarian syndrome (PCOS) develops due to hormonal imbalance and hyperandrogenism. Animal models are widely used to study PCOS because they mimic essential characteristics of human PCOS; however, the pathogenesis of PCOS remains unclear. Different sources of novel drugs are currently being screened as therapeutic strategies to alleviate PCOS and its symptoms. Simplified cell line in-vitro models could be preliminarily used to screen the bioactivity of various drugs. This review describes different cell line models focusing on the PCOS condition and its complications. Therefore, the bioactivity of the drugs could be preliminarily screened in a cell line model before moving to higher animal models.

Differences in metabonomic profiles of abdominal subcutaneous adipose tissue in women with polycystic ovary syndrome

INTRODUCTION

Polycystic ovary syndrome (PCOS) is a complex endocrine disorder that often coexists with a metabolic disorder. Studies have demonstrated that the malfunction of adipose tissue, particularly abdominal adipose tissue, could exacerbate reproductive and metabolic problems in PCOS patients. Adipose tissue-secreted signaling mediators (e.g., lipids and metabolites) would then interact with other body organs, including the ovary, to maintain the systemic equilibrium.

METHODS

In this study, we examined adipose samples from PCOS patients and unaffected individuals using a liquid chromatography-mass spectrometry-based metabonomics approach (LC-MS/MS). PCOS biomarkers were selected using multivariate statistical analysis.

RESULTS

Our pathway analysis revealed that these differential metabolites could be engaged in inflammatory diseases and mitochondrial beta-oxidation. We further developed an in vitro PCOS cell model to examine the effects of hyperandrogenism on granulosa cells and related metabolic disorders. We noted that isoleucine recovered the promotive effect on cell apoptosis, inhibitory effect on cell proliferation, sex hormone secretion, and mitochondrial function induced by dehydroepiandrosterone. Our gas chromatography-mass spectrometry targeted analysis (GC-MS/MS) revealed that isoleucine was significantly decreased in PCOS patients.

DISCUSSION

Based on these results, we speculate that metabolome alterations are vital in ameliorating PCOS symptoms. This may be a novel therapeutic target for PCOS treatment. Our study provides preliminary evidence that these findings will enhance our ability to accurately diagnose and intervene in PCOS.

Acetate: A therapeutic candidate against renal disorder in a rat model of polycystic ovarian syndrome

Various endocrinometabolic diseases, inclusively polycystic ovarian syndrome (PCOS) has been linked with increased risk of renal dysfunction with attendant cardiovascular disease (CVD) in women of reproductive age. Short chain fatty acids (SCFAs) especially acetate have been suggested as an immunometabolic modulator. However, the impact of SCFAs, particularly acetate on renal disorder in PCOS individuals is unknown. The present study therefore hypothesized that acetate would circumvent renal dysfunction in a rat model of PCOS, probably by suppressing NF-κB-dependent mechanism. Eight-week-old female Wistar rats were randomly distributed into four groups (n = 6), which received vehicle, sodium acetate (200 mg/kg), letrozole (1 mg/kg) and letrozole plus sodium acetate, respectively. The administrations were done by oral gavage once daily for a duration of 21 days. Animals with PCOS showed insulin resistance, lipid dysmetabolism, hyperandrogenism, hyperleptinemia and hypoadiponectinemia. Besides, the result also revealed increased renal malondialdehyde, lactate production, inflammatory mediators (NF-κB and TNF-α), urea and creatinine concentration. Immunohistochemical evaluation of renal tissue also demonstrated severe expression of apoptosis and inflammation with BAX/NLRP3 antibodies. However, supplementation with acetate significantly attenuated these anomalies. Collectively, the present results suggest that acetate abolishes renal dysfunction in experimentally induced PCOS animals by attenuating androgen excess, apoptosis, oxidative stress and NF-κB/NLRP3 immunoreactivity.

Androgen-induced insulin resistance is ameliorated by deletion of hepatic androgen receptor in females

Androgen excess is one of the most common endocrine disorders of reproductive-aged women, affecting up to 20% of this population. Women with elevated androgens often exhibit hyperinsulinemia and insulin resistance. The mechanisms of how elevated androgens affect metabolic function are not clear. Hyperandrogenemia in a dihydrotestosterone (DHT)-treated female mouse model induces whole body insulin resistance possibly through activation of the hepatic androgen receptor (AR). We investigated the role of hepatocyte AR in hyperandrogenemia-induced metabolic dysfunction by using several approaches to delete hepatic AR via animal-, cell-, and clinical-based methodologies. We conditionally disrupted hepatocyte AR in female mice developmentally (LivARKO) or acutely by tail vein injection of an adeno-associated virus with a liver-specific promoter for Cre expression in AR^fl/fl mice (adLivARKO). We observed normal metabolic function in littermate female Control (AR^fl/fl ) and LivARKO (AR^fl/fl ; Cre^+/- ) mice. Following chronic DHT treatment, female Control mice treated with DHT (Con-DHT) developed impaired glucose tolerance, pyruvate tolerance, and insulin tolerance, not observed in LivARKO mice treated with DHT (LivARKO-DHT). Furthermore, during an euglycemic hyperinsulinemic clamp, the glucose infusion rate was improved in LivARKO-DHT mice compared to Con-DHT mice. Liver from LivARKO, and primary hepatocytes derived from LivARKO, and adLivARKO mice were protected from DHT-induced insulin resistance and increased gluconeogenesis. These data support a paradigm in which elevated androgens in females disrupt metabolic function via hepatic AR and insulin sensitivity was restored by deletion of hepatic AR.

Hepatic Igf1-Deficiency Protects Against Atherosclerosis in Female Mice

Atherosclerosis is the leading cause of cardiovascular disease (CVD), with distinct sex-specific pathogenic mechanisms that are poorly understood. Aging, a major independent risk factor for atherosclerosis, correlates with a decline in circulating insulin-like growth factor-1 (IGF-1). However, the precise effects of Igf1 on atherosclerosis remain unclear. In the present study, we assessed the essential role of hepatic Igf1, the major source of circulating IGF-1, in atherogenesis. We generated hepatic Igf1-deficient atherosclerosis-prone apolipoprotein E (ApoE)-null mice (L-Igf1-/-ApoE-/-) using the Cre-loxP system driven by the Albumin promoter. Starting at 6 weeks of age, these mice and their littermate controls, separated into male and female groups, were placed on an atherogenic diet for 18 to 19 weeks. We show that hepatic Igf1-deficiency led to atheroprotection with reduced plaque macrophages in females, without significant effects in males. This protection from atherosclerosis in females was associated with increased subcutaneous adiposity and with impaired lipolysis. Moreover, this impaired lipid homeostasis was associated with disrupted adipokine secretion with reduced circulating interleukin-6 (IL-6) levels. Together, our data show that endogenous hepatic Igf1 plays a sex-specific regulatory role in atherogenesis, potentially through athero-promoting effects of adipose tissue-derived IL-6 secretion. These data provide potential novel sex-specific mechanisms in the pathogenesis of atherosclerosis.

Chronic niacin administration ameliorates ovulation, histological changes in the ovary and adiponectin concentrations in a rat model of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is one of the most common ovarian diseases among women of reproductive age. The reproductive and metabolic traits of PCOS are underpinned by adipocyte dysfunction, especially diminished adiponectin secretion. Based on evidence that niacin stimulates adiponectin secretion, this study evaluated the effects of niacin on adiponectin concentrations and reproductive traits in a rat model of PCOS. PCOS was induced by single injection of 4mg kg-1 oestradiol valerate (i.m.), and PCOS groups were administered orally with saline or niacin (10 or 25mg kg-1) daily for 30 days after PCOS induction. The control group received 0.2mL sesame oil (i.m.) only. At the end of the experimental period, serum samples and ovaries were collected for adiponectin, histological and molecular analyses. Niacin reduced the bodyweight gain and increased ovary weights in PCOS rats. Niacin also increased the number of normal antral follicles and corpora lutea while reducing the number of cystic follicles and the thickness of theca interna. Moreover, niacin significantly increased serum adiponectin concentration and the gene expression of adiponectin and its type 1 receptor. In conclusion, this study indicates that niacin reduces cystic follicles and improves ovulation in PCOS rats. Adiponectin signalling may have contributed, in part, to the beneficial effects.

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

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

Physical Exercise following bariatric surgery in women with Morbid obesity: Study protocol clinical trial (SPIRIT compliant)

BACKGROUND

Severe and morbid obesity are increasing globally, particularly in women. As BMI increases, the likelihood of anovulation is higher. The primary aim of the EMOVAR clinical trial is to examine, over the short (16 weeks) and medium (12 months) term, the effects of a supervised physical exercise program (focused primarily on aerobic and resistance training) on ovarian function in women with severe/morbid obesity who have undergone bariatric surgery. Secondary objectives are to examine the effects of the intervention on chronic inflammation, insulin resistance, arterial stiffness, physical fitness, and health-related quality of life.

METHODS

This is a randomized controlled trial in which ∼40 female bariatric surgery patients, aged between 18 and 45 years old, will be included. Participants assigned to the experimental group will perform a total of 48 sessions of supervised concurrent (strength and aerobic) training (3 sessions/week, 60 min/session) spread over 16 weeks. Patients assigned to the control group will receive lifestyle recommendations. Outcomes will be assessed at baseline, week 16 (i.e., after the exercise intervention) and 12 months after surgery. The primary outcome is ovarian function using the Sex-Hormone Binding Globuline, measured in serum. Secondary outcomes are serum levels of anti-mullerian hormone, TSH, T4, FSH, LH, estradiol, prolactine, and free androgen index, as well as oocyte count, the diameters of both ovaries, endometrial thickness, and uterine arterial pulsatility index (obtained from a transvaginal ultrasound), the duration of menstrual bleeding and menstrual cycle duration (obtained by personal interview) and hirsutism (Ferriman Gallwey Scale). Other secondary outcomes include serum markers of chronic inflammation and insulin resistance (i.e., C-reactive protein, interleukin 6, tumor necrosis factor-alpha, leptin, glomerular sedimentation rate, glucose, insulin and the HOMA-IR), arterial stiffness, systolic, diastolic and mean blood pressure, body composition, and total weight loss. Physical fitness (including cardiorespiratory fitness, muscular strength, and flexibility), health-related quality of life (SF-36 v2) and sexual function (Female Sexual Function Index) will also be measured.

DISCUSSION

This study will provide, for the first time, relevant information on the effects of exercise training on ovarian function and underlying mechanisms in severe/morbid obese women following bariatric surgery.

TRIAL REGISTRATION NUMBER

ISRCTN registry (ISRCTN27697878).

Animal Models for Human Polycystic Ovary Syndrome (PCOS) Focused on the Use of Indirect Hormonal Perturbations: A Review of the Literature

Hormonal disturbances, such as hyperandrogenism, are considered important for developing polycystic ovary syndrome (PCOS) in humans. Accordingly, directly hormone-regulated animal models are widely used for studying PCOS, as they replicate several key PCOS features. However, the pathogenesis and treatment of PCOS are still unclear. In this review, we aimed to investigate animal PCOS models and PCOS-like phenotypes in animal experiments without direct hormonal interventions and determine the underlying mechanisms for a better understanding of PCOS. We summarized animal PCOS models that used indirect hormonal interventions and suggested or discussed pathogenesis of PCOS-like features in animals and PCOS-like phenotypes generated in other animals. We presented integrated physiological insights and shared cellular pathways underlying the pathogenesis of PCOS in reviewed animal models. Our review indicates that the hormonal and metabolic changes could be due to molecular dysregulations, such as upregulated PI3K-Akt and extracellular signal-regulated kinase (ERK) signalling, that potentially cause PCOS-like phenotypes in the animal models. This review will be helpful for considering alternative animal PCOS models to determine the cellular/molecular mechanisms underlying PCOS symptoms. The efforts to determine the specific cellular mechanisms of PCOS will contribute to novel treatments and control methods for this complex syndrome.

Body fat percentage is a better marker than body mass index for determining inflammation status in polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is an endocrinopathic disorder most commonly experienced by women of reproductive age, and it is characterized by a low-grade chronic inflammatory condition. Excessive fat deposit has been long considered as an etiological factor in the pathogenesis of this inflammatory condition. Currently, body mass index (BMI) or percentage of body fat is used as a marker to assess the body fat composition of a person.

OBJECTIVE

To determine whether BMI or body fat percentage (BFP) can be used as a better marker for measuring inflammation related to body fat accumulation in polycystic ovary syndrome patients.

MATERIALS AND METHODS

This study took place at the Center for Reproductive Medicine, Yasmin Clinic, Cipto Mangunkusumo Hospital from January to December 2015. In this cross-sectional study, 32 reproductive age women with PCOS according to the Rotterdam criteria (2003) participated. Women with hyperandrogenism caused by non-classic congenital adrenal hyperplasia, pregnant and lactating women, etc., were excluded. Some variables such as BMI, clinical hyperandrogenism sign, BFP, and inflammatory markers were assessed and statistically analyzed.

RESULTS

From a total of 32 subjects of the study, BFP had a significant positive correlation with procalcitonin levels (r=0.35; p=0.048), while BMI did not (r=0.27; p=0.131).

CONCLUSION

BFP can be used as a better marker for measuring inflammation related to body fat accumulation in PCOS subjects.

Prenatal androgen exposure causes hypertension and gut microbiota dysbiosis

BACKGROUND

Conditions of excess androgen in women, such as polycystic ovary syndrome (PCOS), often exhibit intergenerational transmission. One way in which the risk for PCOS may be increased in daughters of affected women is through exposure to elevated androgens in utero. Hyperandrogenemic conditions have serious health consequences, including increased risk for hypertension and cardiovascular disease. Recently, gut dysbiosis has been found to induce hypertension in rats, such that blood pressure can be normalized through fecal microbial transplant. Therefore, we hypothesized that the hypertension seen in PCOS has early origins in gut dysbiosis caused by in utero exposure to excess androgen. We investigated this hypothesis with a model of prenatal androgen (PNA) exposure and maternal hyperandrogenemia by single-injection of testosterone cypionate or sesame oil vehicle (VEH) to pregnant dams in late gestation. We then completed a gut microbiota and cardiometabolic profile of the adult female offspring.

RESULTS

The metabolic assessment revealed that adult PNA rats had increased body weight and increased mRNA expression of adipokines: adipocyte binding protein 2, adiponectin, and leptin in inguinal white adipose tissue. Radiotelemetry analysis revealed hypertension with decreased heart rate in PNA animals. The fecal microbiota profile of PNA animals contained higher relative abundance of bacteria associated with steroid hormone synthesis, Nocardiaceae and Clostridiaceae, and lower abundance of Akkermansia, Bacteroides, Lactobacillus, Clostridium. The PNA animals also had an increased relative abundance of bacteria associated with biosynthesis and elongation of unsaturated short chain fatty acids (SCFAs).

CONCLUSIONS

We found that prenatal exposure to excess androgen negatively impacted cardiovascular function by increasing systolic and diastolic blood pressure and decreasing heart rate. Prenatal androgen was also associated with gut microbial dysbiosis and altered abundance of bacteria involved in metabolite production of short chain fatty acids. These results suggest that early-life exposure to hyperandrogenemia in daughters of women with PCOS may lead to long-term alterations in gut microbiota and cardiometabolic function.

The relationship between IL-18 and atherosclerotic cardiovascular risk in Egyptian lean women with polycystic ovary syndrome

BACKGROUND

Polycystic ovarian syndrome (PCOS) is the most common endocrine disorder among women of reproductive age. The evidence in support of low-grade inflammation in PCOS as an etiology is emerging. Inflammation is likely to be associated with other prominent aspects of PCOS including insulin resistance (IR) and cardiovascular disease (CVD) risk. Interleukin-18 (IL-18) is considered as a strong marker of inflammation.

OBJECTIVES

Evaluation of the relation between serum IL-18 and atherosclerotic CVD (ASCVD) risk in Egyptian lean females with PCO.

METHODS

This study included control group of healthy lean normally menstruating females, lean PCOS group (BMI < 25 kg/m²), and obese PCOS group (BMI > 25 kg/m²) presented with infertility and diagnosed according to Rotterdam criteria. Measurements of serum lipid profile, IR, and IL-18 were done.

RESULTS

Lipid accumulation product (LAP), IR and ASCVD risk were significantly higher in PCOS patients (lean and obese) compared to controls and in obese compared to lean. Serum IL-18 was significantly higher in the PCOV groups compared to the controls and correlated directly with LAP, IR and ASCVD risk.

CONCLUSION

IL-18 is elevated in PCOS patients even in lean ones and is correlated with IR and ASCVD risk.

The Effect of Curcumin on TNF-α, IL-6 and CRP Expression in a Model of Polycystic Ovary Syndrome as an Inflammation State

BACKGROUND

Having low-grade chronic inflammation such as elevated C-reactive protein (CRP), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) plays a crucial role in polycystic ovary syndrome (PCOS). This study aimed at investigating the therapeutic effects of curcumin on IL-6, CRP and TNF-α and symptoms of polycystic ovary syndrome.

METHODS

In this research, 72 female adult Wistar rats were divided into control (n=12), PCOS (n=12) and curcumin-treated PCOS groups (n=48). PCOS was induced by injection of estradiol valerate (2 mg/kg-one-step). PCOS rats were divided into control and experimental groups which received daily intraperitoneal injection of curcumin. After 60 days of syndrome induction, ovaries were collected for histological and immunohistochemical evaluations. Serum IL-6 and CRP was detected by the ELISA kit. Data were analyzed using In-Stat 3 via one-way analysis of variance (ANOVA) and p<0.05 was considered statistically significant.

RESULTS

Histological studies showed a significant reduction in thickness of theca layer and increase in the number of corpus luteum (CL) diameter in the curcumin-treated group compared with the PCOS group; also inflammatory markers such as IL-6 and CRP significantly decreased in groups treated with curcumin compared with PCOS groups. Regarding immunohistochemical analysis, the expression of TNF-α in granulosa layer and follicular fluid of follicles and ovarian cysts in PCOS group was more than the control group's expression. However, expression of this factor in the ovaries treated with curcumin was decreased.

CONCLUSION

This study showed that the anti-inflammatory and antioxidant effects of curcumin on PCOS may be due to its inhibitory effect on expression and levels of TNF-α, serum IL-6 and CRP.

Low-Dose Dihydrotestosterone Drives Metabolic Dysfunction via Cytosolic and Nuclear Hepatic Androgen Receptor Mechanisms

Androgen excess in women is associated with metabolic dysfunction (e.g., obesity, hyperinsulinemia, insulin resistance, and increased risk of type 2 diabetes) and reproductive dysfunction (e.g., polycystic ovaries, amenorrhea, dysregulated gonadotropin release, and infertility). We sought to identify the effects of androgen excess on glucose metabolic dysfunction and the specific mechanisms of action by which androgens are inducing pathology. We developed a mouse model that displayed pathophysiological serum androgen levels with normal body mass/composition to ensure that the phenotypes were directly from androgens and not an indirect consequence of obesity. We performed reproductive tests, metabolic tests, and hormonal assays. Livers were isolated and examined via molecular, biochemical, and histological analysis. Additionally, a low-dose dihydrotestosterone (DHT) cell model using H2.35 mouse hepatocytes was developed to study androgen effects on hepatic insulin signaling. DHT mice demonstrated impaired estrous cyclicity; few corpora lutea in the ovaries; glucose, insulin, and pyruvate intolerance; and lowered hepatic insulin action. Mechanistically, DHT increased hepatic androgen-receptor binding to phosphoinositide-3-kinase (PI3K)-p85, resulting in dissociation of PI3K-p85 from PI3K-p110, leading to reduced PI3K activity and decreased p-AKT and, thus, lowered insulin action. DHT increased gluconeogenesis via direct transcriptional regulation of gluconeogenic enzymes and coactivators. The hepatocyte model recapitulated the in vivo findings. The DHT-induced hepatocyte insulin resistance was reversed by the androgen-receptor antagonist, flutamide. These findings present a phenotype (i.e., impaired glucose tolerance and disrupted glucose metabolism) in a lean hyperandrogenemia model (low-dose DHT) and data to support 2 molecular mechanisms that help drive androgen-induced impaired glucose metabolism.

The Role of Sex and Sex Hormones in Regulating Obesity-Induced Inflammation

Metabolic and non-metabolic complications due to obesity are becoming more prevalent, yet our understanding of the mechanisms driving these is not. This is due to individual risk factor variability making it difficult to predict disease outcomes such as diabetes and insulin resistance. Gender is a critical factor in obesity outcomes with women having more adiposity but reduced metabolic complications compared to men. The role of immune system activation during obesity is an emerging field that links adiposity to metabolic syndrome. Furthermore, evidence from animal models suggests that sex differences exist in immune responses and, therefore, could be a possible mechanism leading to sex differences in metabolic disease. While there is still much to learn in the area of sex-differences research, this chapter will review the current knowledge and literature detailing the role of sex and sex hormones on adiposity and metabolically induced inflammation in obesity.

Up-regulation of miR-21 and 146a expression and increased DNA damage frequency in a mouse model of polycystic ovary syndrome (PCOS)

Introduction: Polycystic ovary syndrome (PCOS), a multigenic endocrine disorder, is highly associated with low-grade chronic inflammation, however its etiology remains unclear. In this study, we employed dehydroepiandrosterone (DHEA)-treated mice to reveal the molecular mechanism of inflammation and its correlation with oxidative stress in PCOS patients.

Methods: miR-21 and miR-146a expression levels were measured using quantitative real-time polymerase chain reaction (qRT-PCR). DNA strand breakage frequency was measured using the single cell gel electrophoresis (SCGE) assay (comet assay) and micronucleus test (MN). CRP levels were measured by ELISA method and ESR values were measured by means of Micro-Dispette (Fisher No: 02-675-256) tubes according to the manufacturer’s instructions. Data were analyzed using one-way ANOVA in SPSS 21.0 software.

Results: Our results showed that miR-21 and miR-146a as inflammation markers were upregulated in the sample group in comparison with control group. Erythrocyte sedimentation rate (ESR) and C- reactive protein (CRP) levels were also increased in mouse models of PCOS (p < 0.000). Micronucleated polychromatic erythrocyte (MNPCE) rates per 1000 polychromatic erythrocyte (PCE) significantly increased in DHEA treated mice (6.22 ± 3.28) in comparison with the controls (2.33 ± 2.23, p < 0.000). Moreover, mean arbitrary unit in DHEA treated animals (277 ± 92) was significantly higher than that in controls (184 ± 76, p = 0.005).

Conclusion: To conclude, increased DNA strand breakage frequency and increased expression levels of miR-21 and miR-146a in DHEA administrated animals suggest that low grade chronic inflammation and oxidative stress can act as the main etiologies of PCOS.

Genetic Rodent Models of Obesity-Associated Ovarian Dysfunction and Subfertility: Insights into Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy affecting women and a leading cause of female infertility worldwide. Defined clinically by the presence of hyperandrogenemia and oligomenorrhoea, PCOS represents a state of hormonal dysregulation, disrupted ovarian follicle dynamics, and subsequent oligo- or anovulation. The syndrome's prevalence is attributed, at least partly, to a well-established association with obesity and insulin resistance (IR). Indeed, the presence of severe PCOS in human genetic obesity and IR syndromes supports a causal role for IR in the pathogenesis of PCOS. However, the molecular mechanisms underlying this causality, as well as the important role of hyperandrogenemia, remain poorly elucidated. As such, treatment of PCOS is necessarily empirical, focusing on symptom alleviation. The generation of knockout and transgenic rodent models of obesity and IR offers a promising platform in which to address mechanistic questions about reproductive dysfunction in the context of metabolic disease. Similarly, the impact of primary perturbations in rodent gonadotrophin or androgen signaling has been interrogated. However, the insights gained from such models have been limited by the relatively poor fidelity of rodent models to human PCOS. In this mini review, we evaluate the ovarian phenotypes associated with rodent models of obesity and IR, including the extent of endocrine disturbance, ovarian dysmorphology, and subfertility. We compare them to both human PCOS and other animal models of the syndrome (genetic and hormonal), explore reasons for their discordance, and consider the new opportunities that are emerging to better understand and treat this important condition.

Impact of Treatment with Metformin on Adipocytokines in Patients with Polycystic Ovary Syndrome: A Meta-Analysis

Background

Metformin is effective for the treatment of polycystic ovary syndrome, but conflicting results regarding its effect on adipocytokine levels (adiponectin, resistin, visfatin, and leptin) in patients with polycystic ovary syndrome receiving metformin treatment have been reported. To provide high-quality evidence about the effect of metformin treatment on adipocytokines in patients with polycystic ovary syndrome, relevant studies that assessed the levels of adipocytokines (adiponectin, resistin, visfatin, and leptin) in patients with polycystic ovary syndrome receiving treatment with metformin administration were reviewed and analyzed.

Methods

A literature search was conducted in the SCI, PUBMED, EMBASE, and Elsevier databases, and personal contact was made with the authors. Standard mean differences and 95% confidence intervals were calculated and combined appropriately. To ensure synthesis of the best available evidence, sensitivity analyses were performed.

Results

A total of 34 data sets were included in 4 different outcomes, involving 744 women with polycystic ovary syndrome and adipocytokine levels measured both before and after metformin administration. Metformin treatment was associated with significantly elevated serum adiponectin concentrations (standard mean differences [95% confidence interval], −0.43 [−0.75 to −0.11]) and decreased serum leptin concentrations (0.65 [0.26 to 1.04]), whereas no significant difference in resistin level (−0.01 [−0.49 to 0.45]) or visfatin level (−0.04 [−1.55 to 1.46]) was found.

Conclusions

Metformin administration was associated with increased serum adiponectin concentrations and decreased serum leptin levels. Further study is needed to elucidate whether this apparent effect decreases the incidence of type 2 diabetes and other metabolic diseases in patients with polycystic ovary syndrome later in life.

High-fat diet induces significant metabolic disorders in a mouse model of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common female endocrinopathy associated with both reproductive and metabolic disorders. Dehydroepiandrosterone (DHEA) is currently used to induce a PCOS mouse model. High-fat diet (HFD) has been shown to cause obesity and infertility in female mice. The possible effect of an HFD on the phenotype of DHEA-induced PCOS mice is unknown. The aim of the present study was to investigate both reproductive and metabolic features of DHEA-induced PCOS mice fed a normal chow or a 60% HFD. Prepubertal C57BL/6 mice (age 25 days) on the normal chow or an HFD were injected (s.c.) daily with the vehicle sesame oil or DHEA for 20 consecutive days. At the end of the experiment, both reproductive and metabolic characteristics were assessed. Our data show that an HFD did not affect the reproductive phenotype of DHEA-treated mice. The treatment of HFD, however, caused significant metabolic alterations in DHEA-treated mice, including obesity, glucose intolerance, dyslipidemia, and pronounced liver steatosis. These findings suggest that HFD induces distinct metabolic features in DHEA-induced PCOS mice. The combined DHEA and HFD treatment may thus serve as a means of studying the mechanisms involved in metabolic derangements of this syndrome, particularly in the high prevalence of hepatic steatosis in women with PCOS.

Mouse models to study polycystic ovary syndrome: a possible link between metabolism and ovarian function?

Polycystic ovary syndrome (PCOS) is the most common cause of female infertility affecting 6-8% of women worldwide. PCOS is characterized by two of the following three criteria: clinical or biochemical hyperandrogenism, oligo- or amenorrhea, and polycystic ovaries (PCO). In addition, women with PCOS are often obese and insulin resistant, and are at risk for type 2 diabetes and cardiovascular disease. The etiology of PCOS remains unknown. Therefore, several animal models for PCOS have been generated to gain insight into the etiology and development of the PCOS-associated phenotypes. Androgens are considered the main culprit of PCOS, and therefore, androgenization of animals is the most frequently used approach to induce symptoms that resemble PCOS. Prenatal or prepubertal androgen treatment results in many characteristics of human PCOS, including anovulation, cyst-like follicles, elevated luteinizing hormone (LH) levels, increased adiposity, and insulin insensitivity. However, PCOS has a heterogeneous presentation, and therefore it is difficult to generate a model that exactly reproduces the reproductive and metabolic phenotypes observed in women with PCOS. In this review, we discuss several mouse models for PCOS, and compare the reproductive and/or metabolic phenotypes observed in several androgen-induced models as well as in several genetic models.

Prevalence of polycystic ovary syndrome in adolescents

OBJECTIVE

To investigate the prevalence of polycystic ovary syndrome (PCOS) in adolescents and its association with obesity.

DESIGN

Cross-sectional study using electronic medical records.

SETTING

Not applicable.

PATIENT(S)

Adolescents aged 15-19 years (n = 137,502).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

PCOS diagnosed or defined according to National Institutes of Health (NIH) criteria.

RESULT(S)

The prevalence of a confirmed diagnosis of PCOS was 0.56%, which increased to 1.14% when undiagnosed cases with documented symptoms qualifying for PCOS according to NIH criteria were included. Compared with normal/underweight girls, the odds ratios (OR and 95% confidence interval [CI]) for confirmed PCOS diagnosis were 3.85 (3.04-4.88), 10.25 (8.16-12.84), and 23.10 (18.66-28.61) for overweight, moderately obese, and extremely obese adolescents, respectively, after adjusting for potential confounders. When adolescents with two or more supportive diagnoses were included (diagnosed and undiagnosed PCOS-NIH), the ORs (95% CI) for PCOS-NIH by weight class were significantly attenuated to 2.95 (2.53-3.44), 6.73 (5.78-7.83), and 14.65 (12.73-16.86) for overweight, moderately obese, and extremely obese adolescents, respectively.

CONCLUSION(S)

Overweight and obesity were associated with higher odds of PCOS in adolescents. Studies based solely on diagnosis codes may underestimate the prevalence of PCOS and overestimate the magnitude of the association between obesity and PCOS.