Hyperandrogenism and Insulin Resistance, Not Changes in Body Weight, Mediate the Development of Endothelial Dysfunction in a Female Rat Model of Polycystic Ovary Syndrome (PCOS)

Defective Uterine Spiral Artery Remodeling and Placental Senescence in a Pregnant Rat Model of Polycystic Ovary Syndrome

Pregnancy-related problems have been linked to impairments in maternal uterine spiral artery (SpA) remodeling. The mechanisms underlying this association are still unclear. It is also unclear whether hyperandrogenism and insulin resistance, the two common manifestations of polycystic ovary syndrome, affect uterine SpA remodeling. We verified previous work in which exposure to 5-dihydrotestosterone (DHT) and insulin (INS) in rats during pregnancy resulted in hyperandrogenism, insulin intolerance, and higher fetal mortality. Exposure to DHT and INS dysregulated the expression of angiogenesis-related genes in the uterus and placenta and also decreased expression of endothelial nitric oxide synthase and matrix metallopeptidases 2 and 9, increased fibrotic collagen deposits in the uterus, and reduced expression of marker genes for SpA-associated trophoblast giant cells. These changes were related to a greater proportion of unremodeled uterine SpAs and a smaller proportion of highly remodeled arteries in DHT + INS-exposed rats. Placentas from DHT + INS-exposed rats exhibited decreased basal and labyrinth zone regions, reduced maternal blood spaces, diminished labyrinth vascularity, and an imbalance in the abundance of vascular and smooth muscle proteins. Furthermore, placentas from DHT + INS-exposed rats showed expression of placental insufficiency markers and a significant increase in cell senescence-associated protein levels. Altogether, this work demonstrates that increased pregnancy complications in polycystic ovary syndrome may be mediated by problems with uterine SpA remodeling, placental functionality, and placental senescence.

Neuropeptide Y directly reduced apoptosis of granulosa cells, and the expression of NPY and its receptors in PCOS subjects

BACKGROUND

Most women with anovulatory infertility show polycystic ovarian syndrome (PCOS), and androgen excess is known as a key factor involved in pathogenicity of PCOS. However, the mechanism of follicular developmental arrest in PCOS is not completely understood. The reproductive function of Neuropeptide Y (NPY) in the ovary during folliculogenesis was previously reported; NPY function in apoptosis and proliferation of granulosa cells (GCs) is follicular-stage dependent. The objective of this study was to investigate the role of NPY in ovarian follicular development and the pathogenesis of PCOS.

METHODS

To simulate the PCOS phenotype using a rat model, 21-day old Sprague Dawley rats were implanted with dihydrotestosterone (DHT) capsule (83 µg/day) and euthanized after 28 days. mRNA and protein content of NPY and its receptors were assessed in GCs from DHT treated rats using RT-qPCR and Western blot, respectively. Proliferation and apoptosis of GCs was assessed using Ki67- and TUNEL assays. Finally, NPY levels were measured in human follicular fluid (FF) from matched PCOS and non-PCOS patients using ELISA.

RESULTS

GCs from DHT treated rats (PCOS-GCs) contained significantly less NPY protein and Npy mRNA by 0.16- and 0.56-fold, respectively, and more NPY receptor type 2 and 5 protein by 2.21- and 3.17-fold, respectively, when compared to sham control. Addition of recombinant NPY to PCOS-GCs culture did not alter Ki67-positive but significantly decreased TUNEL-positive cells by 0.65-fold, but not to baseline levels. There was no significant difference in NPY levels in FF between PCOS and non-PCOS subjects.

CONCLUSIONS

These results indicate that DHT modulates expression of NPY and its receptors, NPY decreases DHT-induced GCs apoptosis. That alterations in NPY's function might be involved in follicular developmental failure of PCOS.

Androgen-Induced Cardiovascular Risk in Polycystic Ovary Syndrome: The Role of T Lymphocytes

An estimated 15-20% of reproductive-age women are affected by polycystic ovary syndrome (PCOS). PCOS is associated with substantial metabolic and cardiovascular long-term consequences. In young women with PCOS, several cardiovascular risk factors may be found, including chronic inflammation, high blood pressure, and elevated leukocytes. These women are at an increased risk of cardiovascular diseases (CVD), not only during the reproductive years, but also with aging and menopause; therefore, the early prevention and treatment of future cardiovascular adverse effects are necessary. The fundamental characteristic of PCOS is hyperandrogenemia, which is associated with increased pro-inflammatory cytokines and T lymphocytes. Whether these factors play a role in the pathophysiology of hypertension, a risk factor of CVD, due to PCOS is not well established. This review will briefly discuss how a modest increase in androgens in females is linked to the development of hypertension through pro-inflammatory cytokines and T lymphocyte subsets and the promotion of renal injury. Moreover, it reveals a few existing research gaps in this area, including the lack of specific therapy directed at androgen-induced inflammation and immune activation, thus emphasizing the necessity to explore the systemic inflammation in women with PCOS to halt the inevitable inflammatory process targeting the underlying abnormalities of CVD.

Association of Insulin Resistance and Elevated Androgen Levels with Polycystic Ovarian Syndrome (PCOS): A Review of Literature

The polycystic ovary syndrome (PCOS) is the disease featured by elevated levels of androgens, ovulatory dysfunction, and morphological abnormalities. At reproductive stage of women, the rate of PCOS occurrence is measured as 6–10% and the prevalence rate may be double. There are different pathophysiological factors involved in PCOS, and they play a major role in various abnormalities in individual patient. It is clear that there is noteworthy elevation of androgen in PCOS, causing substantial misery and infertility problems. The overexposure of androgen is directly linked with insulin resistance and hyperinsulinaemia. It has been reported previously that PCOS is related to cardiac metabolic miseries and potently increases the risk of heart diseases. Endometrial cancer is also a serious concern which is reported with exceedingly high incidence in women with PCOS. However, the overexposure of androgen has direct and specific influence on the development of insulin resistance. Although many factors are involved, resistance to the insulin and enhanced level of androgen are considered the major causes of PCOS. In the present review, we have focused on the pathophysiology and major revolutions of insulin resistance and excessive levels of androgen in females with PCOS.

Metformin does not improve insulin sensitivity over hypocaloric diets in women with polycystic ovary syndrome: a systematic review of 12 studies

OBJECTIVE

To improve insulin action, most clinicians prescribe Metformin in patients with insulin resistance (IR). Women with polycystic ovary syndrome (PCOS), in which IR is an important physiopathological mechanism, treatment with Metformin and specialized diets have been suggested to reduce the patient's IR. However, numerous studies have demonstrated conflicting results with respect to supplementing a diet with Metformin. Therefore, we conducted a meta-analysis to determine if Metformin provides a benefit in conjunction with hypocaloric diets to improve insulin sensitivity in PCOS women.

METHODS

PubMed, SCOPUS, LILACS, and EBSCO databases and retrieved studies' bibliographies were searched for prospective studies that investigated the effect between Metformin and hypocaloric diets in PCOS women until April 2020. Pre- and post-intervention values for fasting plasma glucose (FPG), fasting plasma insulin (FPI), and IR indices (HOMA1-IR, ISI, and QUICKI) were extracted. Using Comprehensive Meta-Analysis software, the pooled standard difference in the means (SDM) and 95%CIs were calculated.

RESULTS

11 publications (12 studies) were selected. There was not a benefit of adding Metformin to a hypocaloric diet with respect to FPG (SDM= -0.17; 95%CI: -0.48-0.14, p = .28) and FPI (SDM = 0.16; 95%CI: -0.24-0.55, p = .45). None of the IR indices also demonstrated any benefit of using Metformin when a diet intervention was implemented (HOMA1-IR: SDM = 0.28; 95%CI: -0.27-0.84, p = .315; ISI: SDM = 0.344; 95%CI: -0.17-0.85, p = .186; QUICKI: SDM= -0.01; 95%CI: -0.42-0.41, p = .968).

CONCLUSION

Here, we determined that adding Metformin to hypocaloric diets did not improve serum glucose or insulin concentrations as well as IR in PCOS women.

Influence of Vitamin D on the Vasoactive Effect of Estradiol in a Rat Model of Polycystic Ovary Syndrome

We examined the vasoactive effect of estradiol in a rat model of early PCOS and the influence of vitamin D deficiency (VDD). We created a model of chronic hyperandrogenism and VDD in adolescent female Wistar rats (N = 46) with four experimental groups: vitamin D supplemented (T-D+), VDD (T-D-), hyperandrogenic and vitamin D supplemented (T+D+), and hyperandrogenic and VDD (T+D-). T+ groups received an 8-week-long transdermal Androgel treatment, D-animals were on vitamin D-reduced diet and D+ rats were supplemented orally with vitamin D3. Estrogen-induced vasorelaxation of thoracic aorta segments were measured with a wire myograph system with or without the inhibition of endothelial nitric oxide synthase (eNOS) or cyclooxygenase-2 (COX-2). The distribution of estrogen receptor (ER), eNOS and COX-2 in the aortic wall was assessed by immunohistochemistry. VDD aortas showed significantly lower estradiol-induced relaxation independently of androgenic status that was further decreased by COX-2 inhibition. COX-2 inhibition failed to alter vessel function in D+ rats. Inhibition of eNOS abolished the estradiol-induced relaxation in all groups. Changes in vascular function in VDD were accompanied by significantly decreased ER and eNOS staining. Short-term chronic hyperandrogenism failed to, but VDD induced vascular dysfunction, compromised estrogen-dependent vasodilatation and changes in ER and eNOS immunostaining.

Obesity-associated cardiovascular risk in women: hypertension and heart failure

The pathogenesis of obesity-associated cardiovascular diseases begins long prior to the presentation of a cardiovascular event. In both men and women, cardiovascular events, and their associated hospitalizations and mortality, are often clinically predisposed by the presentation of a chronic cardiovascular risk factor. Obesity increases the risk of cardiovascular diseases in both sexes, however, the clinical prevalence of obesity, as well as its contribution to crucial cardiovascular risk factors is dependent on sex. The mechanisms via which obesity leads to cardiovascular risk is also discrepant in women between their premenopausal, pregnancy and postmenopausal phases of life. Emerging data indicate that at all reproductive statuses and ages, the presentation of a cardiovascular event in obese women is strongly associated with hypertension and its subsequent chronic risk factor, heart failure with preserved ejection fraction (HFpEF). In addition, emerging evidence indicates that obesity increases the risk of both hypertension and heart failure in pregnancy. This review will summarize clinical and experimental data on the female-specific prevalence and mechanisms of hypertension and heart failure in women across reproductive stages and highlight the particular risks in pregnancy as well as emerging data in a high-risk ethnicity in women of African ancestry (AA).

Insulin resistance and high molecular weight adiponectin in obese and non-obese patients with Polycystic Ovarian Syndrome (PCOS)

BACKGROUND

Polycystic ovarian syndrome (PCOS) is the most common endocrinopathy among young women. Insulin resistance is a key feature in the pathogenesis of PCOS; also high molecular weight adiponectin is a marker of insulin resistance. The aim of this study was to evaluate the insulin resistance, metabolic and androgenic profiles and high molecular weight adiponectin in obese and non-obese PCOS patients.

METHODS

In this cross-sectional study in outpatient endocrinology clinics of Shiraz University of Medical Sciences, 80 women aged 17-43 years old with PCOS were enrolled. Biochemical and hormonal assay was done on fasting blood sample on the third day of follicular phase.

RESULTS

The individuals had a mean age of 28.39 ± 6.56 years, mean weight of 65.41 ± 12.59 Kg, mean BMI of 25.5 ± 4.9, and mean waist circumference of 88.0 ± 13.1 cm. Of all individuals 20% had frank insulin resistance with HOMA-IR > 3.8. Although the obese PCOS patients had lower levels of high molecular weight adiponectin (P = 0.03) than the normal weight PCOS individuals, the level of insulin and insulin resistance was not different in them (P = 0.13, 0.13). Patients with classic PCOS phenotype significantly had higher levels of insulin resistance and free androgen index (P < 0.001, 0.001). We found a significant correlation between the insulin level and free androgen index (correlation coefficient: 0.266 and P = 0.018) after adjusting for BMI.

CONCLUSION

This cross-sectional study showed a high incidence of insulin resistance in PCOS patients independent of obesity, and determined BMI related lower level of high molecular weight adiponectin in obese PCOS individuals. More detailed studies are warranted for evaluation of insulin resistance and its pathophysiologic role in PCOS.

The "Hitchhiker's Guide to the Galaxy" of Endothelial Dysfunction Markers in Human Fertility

Endothelial dysfunction is an early event in the pathogenesis of atherosclerosis and represents the first step in the pathogenesis of cardiovascular diseases. The evaluation of endothelial health is fundamental in clinical practice and several direct and indirect markers have been suggested so far to identify any alterations in endothelial homeostasis. Alongside the known endothelial role on vascular health, several pieces of evidence have demonstrated that proper endothelial functioning plays a key role in human fertility and reproduction. Therefore, this state-of-the-art review updates the endothelial health markers discriminating between those available for clinical practice or for research purposes and their application in human fertility. Moreover, new molecules potentially helpful to clarify the link between endothelial and reproductive health are evaluated herein.

Acetate causes renoprotection like androgen and mineralocorticoid receptors blockade in testosterone-exposed pregnant rats

The kidney plays a critical role in human health and deviation from its normal function can lead to severe morbidity and mortality. Exposure to excess testosterone in women has been linked to several disorders, including kidney disorder and acting undoubtedly through androgen receptor (AR), whereas the involvement of mineralocorticoid receptor (MR) is unclear. Likewise, the renal effect of sodium acetate (SAc) during late gestational exposure to testosterone is not well known. We hypothesized that SAc or MR blockade would protect the kidney of testosterone-exposed pregnant rats against glutathione and adenosine depletion. Twenty-five pregnant Wistar rats were treated (sc) with olive oil, testosterone propionate (0.5 mg/kg) singly or in combination with SAc (200 mg/kg; p.o.), androgen receptor (AR) blocker, flutamide (Flu; 7.5 mg/kg; p.o.) or (MR) blocker, eplerenone (Eple; 0.5 mg/kg) between gestational days 14 and 19. Glutathione, adenosine and nitric oxide were decreased while uric acid (UA), xanthine oxidase (XO), malondialdehyde (MDA), lactate dehydrogenase activity and free fatty acids were increased in the kidneys of gestational rats exposed to testosterone. Also, plasma urea and creatinine were elevated. SAc and Eple reversed tested testosterone-induced effects in gestational rats. The exposure to testosterone impairs renal antioxidant defense via AR and MR during late gestation in pregnant rats. The study also provides evidence that sodium acetate protects the kidneys of gestational testosterone-exposed rats against defective antioxidant defense in like manner as MR or AR antagonist.

Pharmacological Approaches to Controlling Cardiometabolic Risk in Women with PCOS

Polycystic ovary syndrome (PCOS) is characterized by elevated androgen production and subclinical changes in cardiovascular and metabolic risk markers. Total cholesterol, high-density lipoprotein (HDL) cholesterol, fasting glucose, and fasting insulin appear to increase specifically in PCOS compared with fertile women. PCOS also confers an increased risk of cardiometabolic disease in later life. Novel biomarkers such as serum’s cholesterol efflux capacity and blood-derived macrophage activation profile may assist in more accurately defining the cardiometabolic risk profile in these women. Aldosterone antagonists, androgen receptor antagonists, 5α-reductase inhibitors, and synthetic progestogens are used to reduce hyperandrogenism. Because increased insulin secretion enhances ovarian androgen production, short-term treatment with metformin and other hypoglycemic agents results in significant weight loss, favorable metabolic changes, and testosterone reduction. The naturally occurring inositols display insulin-sensitizing effects and may be also used in this context because of their safety profile. Combined oral contraceptives represent the drug of choice for correction of androgen-related symptoms. Overall, PCOS management remains focused on specific targets including assessment and treatment of cardiometabolic risk, according to disease phenotypes. While new options are adding to established therapeutic approaches, a sometimes difficult balance between efficacy and safety of available medications has to be found in individual women.

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.

Maternal androgen excess induces cardiac hypertrophy and left ventricular dysfunction in female mice offspring

Aims

Polycystic ovary syndrome (PCOS) is a common endocrinopathy that is suggested to increase the risk for cardiovascular disease. How PCOS may lead to adverse cardiac outcomes is unclear and here we hypothesized that prenatal exposure to dihydrotestosterone (DHT) and/or maternal obesity in mice induce adverse metabolic and cardiac programming in female offspring that resemble the reproductive features of the syndrome.

Methods and results

The maternal obese PCOS phenotype was induced in mice by chronic high-fat–high-sucrose consumption together with prenatal DHT exposure. The prenatally androgenized (PNA) female offspring displayed cardiac hypertrophy during adulthood, an outcome that was not accompanied by aberrant metabolic profile. The expression of key genes involved in cardiac hypertrophy was up-regulated in the PNA offspring, with limited or no impact of maternal obesity. Furthermore, the activity of NADPH oxidase, a major source of reactive oxygen species in the cardiovascular system, was down-regulated in the PNA offspring heart. We next explored for early transcriptional changes in the heart of newly born PNA offspring, which could account for the long-lasting changes observed in adulthood. Neonatal PNA hearts displayed an up-regulation of transcription factors involved in cardiac hypertrophic remodelling and of the calcium-handling gene, Slc8a2. Finally, to determine the specific role of androgens in cardiovascular function, female mice were continuously exposed to DHT from pre-puberty to adulthood, with or without the antiandrogen flutamide. Continuous exposure to DHT led to adverse left ventricular remodelling, and increased vasocontractile responses, while treatment with flutamide partly alleviated these effects.

Conclusion

Taken together, our results indicate that intrauterine androgen exposure programmes long-lasting heart remodelling in female mouse offspring that is linked to left ventricular hypertrophy and highlight the potential risk of developing cardiac dysfunction in daughters of mothers with PCOS.

Androgens drive microvascular endothelial dysfunction in women with polycystic ovary syndrome: role of the endothelin B receptor

KEY POINTS

Polycystic ovary syndrome (PCOS) is a complex syndrome with cardiovascular risk factors, including obesity and insulin resistance. PCOS is also associated with high androgens, increases the risk of cardiovascular dysfunction in women. Due to the complexity of PCOS, had it has been challenging to isolate specific causes of the cardiovascular dysfunction. Our measure of cardiovascular dysfunction (endothelial dysfunction) was most profound in lean women with PCOS. The endothelin-1-induced vasodilation in these PCOS subject, was dependent on the ET_B R but was not NO-dependent. We also demonstrated oestrogen administration improved endothelial function in lean and obese women with PCOS likely because oestrogen increased NO availability. Our studies indicate a primary role for androgens in cardiovascular dysfunction in PCOS.

ABSTRACT

Endothelin-1 (ET-1) is an indicator of endothelial injury and dysfunction and is elevated in women with androgen excess polycystic ovary syndrome (AE-PCOS). The endothelin B receptor (ET_B R) subtype mediates vasodilatation, but is blunted in women with PCOS. We hypothesized that androgen drives endothelial dysfunction in AE-PCOS women and oestradiol (EE) administration reverses these effects. We assessed microvascular endothelial function in women with (7 lean and 7 obese) and without AE-PCOS (controls, 6 lean, 7 obese). Only obese AE-PCOS women were insulin resistant (IR). We evaluated cutaneous vascular conductance (%CVC_max ) with laser Doppler flowmetry during low dose intradermal microdialysis ET-1 perfusions (1, 3, 4, 5 and 7 pmol) with either lactated Ringer solution alone, or with ET_B R (BQ-788), or nitric oxide (NO) inhibition (l-NAME). Log[ET-1]-%maxCVC dose-response curves demonstrated reduced vasodilatory responses to ET-1 in lean AE-PCOS (logED₅₀ , 0.59 ± 0.08) versus lean controls (logED₅₀ , 0.49 ± 0.09, P < 0.05), but not compared to obese AE-PCOS (logED₅₀ , 0.65 ± 0.09). ET_B R inhibition decreased ET-1-induced vasodilatation in AE-PCOS women (logED₅₀ , 0.64 ± 0. 22, P < 0.05). This was mechanistically observed at the cellular level, with ET-1-induced, DAF-FM-measurable endothelial cell NO production, which was abrogated by dihydrotestosterone in an androgen receptor-dependent manner. EE augmented the cutaneous vasodilating response to ET-1(logED₅₀ 0.29 ± 0.21, 0.47 ± 0.09, P < 0.05 for lean and obese, respectively). Androgens drive endothelial dysfunction in lean and obese AE-PCOS. We propose that the attenuated ET-1-induced vasodilatation in AE-PCOS is a consequence of androgen receptor-mediated, suppressed ET_B R-stimulated NO production, and is reversed with EE.

Spaceflight-related ocular changes: the potential role of genetics, and the potential of B vitamins as a countermeasure

PURPOSE OF REVIEW

Within the last decade, it was realized that during and after long-duration spaceflight, some astronauts experience ophthalmic abnormalities including refractive changes, optic disc edema, globe flattening, choroidal folds, and cotton wool spots. Much research has been initiated and conducted, but little evidence is available to differentiate affected crewmembers.

RECENT FINDINGS

The first published data to distinguish between affected and nonaffected crewmembers identified biochemical differences in affected astronauts: one-carbon pathway metabolite concentrations were higher in these individuals than in nonaffected astronauts, even before flight. These data led to findings that genetics and B-vitamin status were predictors of the incidence of the ophthalmic abnormalities. A multihit hypothesis was developed, with genetics and B-vitamin status as two of several important elements that all contribute to endothelial dysfunction and ultimately to ophthalmic changes after flight. One of these contributing factors - response to carbon dioxide exposure - was recently documented to be affected by the same one-carbon pathway genetics.

SUMMARY

This line of research may help identify which astronauts are at risk of these ophthalmic changes, and allow targeted treatment. This research may have implications for clinical populations, including patients with polycystic ovary syndrome, that have similar biochemical, endocrine, and genetic characteristics, and it may shed light on why links between cardiovascular disease and the metabolites homocysteine and folate have been elusive and confounded.

Pregnancy-Induced Physiologic Adaptation of the Abdominal Aorta Is Associated with Changes in Gene Expression and Genomic Methylation

BACKGROUND/AIMS

Ten-eleven translocation 2 (Tet2), a DNA demethylase enzyme, has been identified as a master epigenetic regulator of vascular smooth muscle cell plasticity. We hypothesized that pregnancy will induce significant adaptive changes in aortic biomechanics that correlate with the Tet family gene expression.

METHODS

Abdominal aortas from pregnant and nonpregnant mice were dissected and cannulated. Intraluminal pressure was adjusted using a pressure-servo system while using a video dimension analyzer to measure the lumen diameter. Quantitative polymerase chain reaction and immunoblot was used to analyze the expression of Tet genes. Global genomic methylation was assessed with the luminometric methylation assay.

RESULTS

Compared to the nonpregnant (NP, 706 ± 8 µm) control group, the aortic luminal diameter was significantly increased in both E18.5 (836 ± 14 µm) and PP30 (889 ± 16 µm) mice. Distensibility was reduced in E18.5 (90 ± 4%) mice and returned to NP values (108 ± 2%) in PP30 (108 ± 3%) mice. Tet2 transcription decreased at the beginning of pregnancy and subsequently increased in late gestation, inversely corresponding to changes in global methylation.

CONCLUSION

Physiologic changes in the aorta were accompanied by changes in gene expression and genomic methylation, suggesting an epigenetic component to maternal vascular remodeling during pregnancy.

Endoglin inhibition by sodium acetate and flutamide ameliorates cardiac defective G6PD-dependent antioxidant defense in gestational testosterone-exposed rats

Gestational androgen excess has been implicated in the development of cardiac dysfunction with poor mechanistic delineation. The role of sodium acetate on cardiac uric acid (UA) production and glucose-6-phosphate dehydrogenase (G6PD)-dependent antioxidant defense in pregnancy is not known. The study therefore sought to test the hypothesis that rats exposed to elevated testosterone in late pregnancy would have increased cardiac UA production and defective G6PD-dependent antioxidant defense. We also hypothesized that sodium acetate (SAc) or androgen receptor blocker, flutamide (Flu) would ameliorate these effects through endoglin inhibition. Twenty-four pregnant Wistar rats were treated (sc) with olive oil, testosterone propionate (0.5 mg/kg) singly or in combination with SAc (200 mg/kg; po) or Flu (7.5 mg/kg; po) in the late gestation between gestational day 14 and 19. The results showed that in the late gestation, testosterone exposure led to increased plasma and cardiac endoglin. In the heart of rats exposed to gestational testosterone there were elevated lactate dehydrogenase, adenosine deaminase, xanthine oxidase, uric acid (UA), cardiac injury markers and decreased G6PD-dependent antioxidant defense. However, either SAc or Flu comparably ameliorated these testosterone-induced effects. The data from the present study revealed that testosterone exposure in the late gestation causes elevated cardiac Eng that is accompanied by increased UA production and defective G6PD-dependent anti-oxidant defenses. Besides, the findings also suggest that the inhibitory effect of SAc or Flu on endoglin attenuates UA production and enhances the G6PD-dependent anti-oxidant barrier, thereby implying that endoglin may be a potentially novel therapeutic intervention for cardiac dysfunction particularly in pregnancy.

Long-Lasting Androgen-Induced Cardiometabolic Effects in Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS), the most common endocrine disorder in women of reproductive age, is characterized by androgen excess and ovarian dysfunction and presents with increased cardiometabolic risk factors such as obesity, insulin resistance, and elevated blood pressure (BP). We previously reported that administration of dihydrotestosterone (DHT) to female rats elicits cardiometabolic derangements similar to those found in women with PCOS. In this study, we tested the hypothesis that the DHT-mediated cardiometabolic derangements observed in PCOS are long lasting despite DHT withdrawal. Four-week-old female Sprague Dawley rats were treated with DHT (7.5 mg/90 days) or placebo for 6 months. DHT was discontinued (ex-DHT), and rats were followed for 6 additional months. After 6 months of DHT withdrawal, food intake, body weight, fat and lean mass, fasting plasma insulin, leptin, and adiponectin were elevated in ex-DHT rats. BP remained significantly elevated, and enalapril, an angiotensin-converting enzyme (ACE) inhibitor, normalized BP in ex-DHT rats. Expression of components of the intrarenal renin-angiotensin system was increased in ex-DHT rats. The cardiometabolic features found in ex-DHT rats were associated with lower plasma androgen levels but increased expression of renal and adipose tissue androgen receptors. In summary, androgen-induced cardiometabolic effects persisted after DHT withdrawal in a PCOS experimental model. Activation of intrarenal renin-angiotensin system plays a major role in the androgen-mediated increase in BP in ex-DHT. Upregulation of the renal and adipose tissue androgen receptor may explain the long-lasting effects of androgens. In clinical scenarios characterized by hyperandrogenemia in women, prompt normalization of androgen levels may be necessary to prevent their long-lasting cardiometabolic effects.

How to choose the suitable animal model of polycystic ovary syndrome?

Polycystic ovary syndrome (PCOS) is a gynecological metabolic and endocrine disorder with uncertain etiology. To understand the etiology of PCOS or the evaluation of various therapeutic agents, different animal models have been introduced. Considering this fact that is difficult to develop an animal model that mimics all aspects of this syndrome, but, similarity of biological, anatomical, and/or biochemical features of animal model to the human PCOS phenotypes can increase its application. This review paper evaluates the recently researched animal models and introduced the best models for different research purposes in PCOS studies. During January 2013 to January 2017, 162 studies were identified which applied various kinds of animal models of PCOS including rodent, primate, ruminant and fish. Between these models, prenatal and pre-pubertal androgen rat models and then prenatal androgen mouse model have been studied in detail than others. The comparison of main features of these models with women PCOS demonstrates higher similarity of these three models to human conditions. Thereafter, letrozole models can be recommended for the investigation of various aspects of PCOS. Interestingly, similarity of PCOS features of post-pubertal insulin and human chorionic gonadotropin rat models with women PCOS were considerable which can make it as a good choice for future investigations.

Cardiometabolic risk in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a common disorder in women of reproductive age. Besides hyperandrogenism, oligomenorrhea and fertility issues, it is associated with a high prevalence of metabolic disorders and cardiovascular risk factors. Several genetic polymorphisms have been identified for possible associations with cardiometabolic derangements in PCOS. Different PCOS phenotypes differ significantly in their cardiometabolic risk, which worsens with severity of androgen excess. Due to methodological difficulties, longer time-scale data about cardiovascular morbidity and mortality in PCOS and about possible beneficial effects of different treatment interventions is missing leaving many issues regarding cardiovascular risk unresolved.

Hyperandrogenemia reduces endothelium-derived hyperpolarizing factor-mediated relaxation in mesenteric artery of female rats

Women with polycystic ovary syndrome (PCOS) are often presented with hyperandrogenemia along with vascular dysfunction and elevated blood pressure. In animal models of PCOS, anti-androgen treatment decreased blood pressure, indicating a key role for androgens in the development of hypertension. However, the underlying androgen-mediated mechanism that contributes to increased blood pressure is not known. This study determined whether elevated androgens affect endothelium-derived hyperpolarizing factor (EDHF)-mediated vascular relaxation responses through alteration in function of gap junctional proteins. Female rats were implanted with placebo or dihydrotestosterone (DHT) pellets (7.5 mg, 90-day release). After 12 weeks of DHT exposure, blood pressure was assessed through carotid arterial catheter and endothelium-dependent mesenteric arterial EDHF relaxation using wire myograph. Connexin expression in mesenteric arteries was also examined. Elevated DHT significantly increased mean arterial pressure and decreased endothelium-dependent EDHF-mediated acetylcholine relaxation. Inhibition of Cx40 did not have any effect, while inhibition of Cx37 decreased EDHF relaxation to a similar magnitude in both controls and DHT females. On the other hand, inhibition of Cx43 significantly attenuated EDHF relaxation in mesenteric arteries of controls but not DHT females. Elevated DHT did not alter Cx37 or Cx40, but decreased Cx43 mRNA and protein levels in mesenteric arteries. In vitro exposure of DHT to cultured mesenteric artery smooth muscle cells dose-dependently downregulated Cx43 expression. In conclusion, increased blood pressure in hyperandrogenic females is due, at least in part, to decreased EDHF-mediated vascular relaxation responses. Decreased Cx43 expression and activity may play a role in contributing to androgen-induced decrease in EDHF function.

Insulin and the polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most prevalent endocrinopathy among women during reproductive age. PCOS is characterised by hyperandrogenaemia, hyperinsulinaemia, and deranged adipokines secretion from the adipose tissue. In addition to the reduced insulin sensitivity, PCOS women exhibit β-cell dysfunction as well. Low birth weight and foetal exposure to androgens may contribute to the development of the PCOS phenotype during life. Further metabolic complications lead to dyslipidaemia, worsening obesity and glucose tolerance, high prevalence of metabolic syndrome, and greater susceptibility to diabetes. PCOS women show age-related existence of hypertension, and subtle endothelial and vascular changes. Adverse reproductive outcomes include anovulatory infertility, and unrecognised potentiation of the hormone-dependent endometrial cancer. The main therapeutic approach is lifestyle modification. Metformin is the primary insulin-sensitising drug to be used as an adjuvant therapy to lifestyle modification in patients with insulin resistance and impaired glucose tolerance, as well as in those referred to infertility treatment. Thiazolidinediones should be reserved for women intolerant of or refractory to metformin, while glucagon-like peptide 1 analogues has a potential therapeutic use in obese PCOS women. Randomised clinical trials and repetitive studies on different PCOS phenotypes for the preventive actions and therapeutic options are still lacking, though.

A Review on Glycosylated Hemoglobin in Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is one of the most common reproductive endocrine disorders among women of reproductive age, with a variety of complications and consequences mostly due to hyperandrogenism and insulin resistance (IR). PCOS patients with IR are at risk for metabolic syndrome and diabetes mellitus (DM) along with its complications such as cardiovascular events. There are several methods for screening IR in patients with PCOS to predict DM and other complications. Fasting plasma glucose test, oral glucose tolerance test, and insulin and glycosylated hemoglobin (HbA1c) levels are some available screening tools for IR. The American Diabetes Association recommended HbA1c to screen for DM because HbA1c is not affected by day-to-day plasma glucose levels and reflects the plasma glucose status during 2-3 months before measurement. Some studies have evaluated the role of HbA1c as a screening method to predict DM in PCOS patients, however, there are still controversies in this matter. Also some studies reported that HbA1c has a correlation with complications of PCOS such as metabolic syndrome and cardiovascular events. We found that HbA1c could be a suitable screening test for IR in PCOS patients but more studies are recommended, omitting confounding factors that could affect IR in patients with PCOS, such as antihyperglycemic agents like metformin, or lifestyle modification, which can be effective in reducing IR in patients with PCOS.

Testosterone downregulates angiotensin II type-2 receptor via androgen receptor-mediated ERK1/2 MAP kinase pathway in rat aorta

Introduction:

Blood pressure is lower in females than males. Angiotensin II type-2 receptor (AT₂R) induces vasodilation. This study determined whether sex differences in vascular AT₂R expression occur and if androgens exert control on AT₂R expression in the vasculature.

Methods:

AT₂Rs in the aorta of male and female Sprague-Dawley rats were examined following alteration in androgen levels by gonadectomy or hormone supplementation.

Results:

AT₂R mRNA and protein expression levels were lower in the aortas of males than females. In males, testosterone withdrawal by castration significantly elevated AT₂R mRNA and protein levels and testosterone replacement restored them. In females, increasing androgen levels decreased AT₂R mRNA and protein expression and this was attenuated by androgen receptor blocker flutamide. Ex vivo, dihydrotestosterone downregulated AT₂R in endothelium-intact but not endothelium-denuded aorta. Dihydrotestosterone-induced AT₂R downregulation in isolated aorta was blocked by an androgen receptor antagonist. Furthermore, blockade of ERK1/2 but not p38 MAP kinase or TGFβ signaling with specific inhibitors abolished dihydrotestosterone-induced AT₂R downregulation.

Conclusion:

Androgens downregulate AT₂R expression levels in aorta, in vivo and ex vivo. The androgen receptor-mediated ERK1/2 MAP kinase-signaling pathway may be a key mechanism by which testosterone downregulates AT₂R expression, implicating androgens’ contributing role to gender differences in vascular AT₂R expression.

Characterization of embryonic stem cell model of polycystic ovary syndrome

The aims of this study are to establish an embryonic stem (ES) cell model of polycystic ovary syndrome and to characterize this ES cell line. ES cells were isolated and cultured from 322 wasted fertilized embryos from polycystic ovary syndrome (PCOS) patients in vitro. They were also characterized by development and differential markers. ES cells from PCOS subject present normal development profile with ES-specific markers such as OCT-4 and SSEA-4. These ES cells can also differentiate into three germ layer derivatives and form teratomas in vivo. ES cells from PCOS patients pose development and differentiation potentials as you would expect of cells from non-PCOS patients; therefore, they can be used as a cellular model to study the pathology of PCOS.