Adiponectin levels in women with polycystic ovary syndrome: a systematic review and a meta-analysis

Relationship between adiponectin and fertility in the female pig

Adiponectin isoforms may mediate different aspects of the pleiotropic function of the protein, including the reproductive process. We examined the pattern of circulating adiponectin and adiponectin system expression in fat and ovarian tissues of hyperfertile and subfertile sows. We demonstrated the presence of five different isoforms of adiponectin (90, 158, 180, 250 and >250 kDa) in the circulation and identified a subgroup of subfertile females that displayed reduced abundance of all adiponectin isoforms as well as a lack of the 250-kDa adiponectin isoform in both serum and follicular fluid. Subfertility in these animals was associated with fewer large follicles and corpora lutea in the ovaries, as well as lower concentrations of 17β-oestradiol in the follicular fluid of large follicles. In addition, subfertile females showed higher adiponectin mRNA in fat tissue and altered mRNA and protein expression of adiponectin and its receptors in the ovary. Changes in the abundance and pattern of circulating adiponectin isoforms have been associated with reproductive disorders in animals and humans, including polycystic ovarian syndrome (PCOS). Our findings suggest that the adiponectin system may play an important role in controlling ovarian function and influencing porcine fertility.

Polycystic Ovary Syndrome: Important Underrecognised Cardiometabolic Risk Factor in Reproductive-Age Women

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder amongst women of reproductive age. Although PCOS is diagnosed exclusively based on reproductive criteria, it is also a metabolic disorder. Insulin resistance, impaired glucose tolerance, type 2 diabetes mellitus, obesity, and dyslipidemia are more common in women with PCOS than in age-comparable women without PCOS. Many of the metabolic abnormalities that manifest in PCOS are worsened by the concurrent incidence of obesity. However, some of these metabolic perturbations occur even in lean women with PCOS and therefore are rightfully recognized as intrinsic to PCOS. The intrinsic factors that produce these metabolic disturbances are reviewed in this paper. The consequences of obesity and the other metabolic aberrations are also discussed. The metabolic perturbations in PCOS patients lead to chronic low-grade inflammation and to cardiovascular impairments that heighten the risk of having cardiovascular disease. Even though many studies have shown an elevation in surrogate biomarkers of cardiovascular disease in PCOS women, it is still not clear to what extent and magnitude the elevation precipitates more frequent and earlier events.

Obesity and PCOS: the effect of metabolic derangements on endometrial receptivity at the time of implantation

Successful embryonic implantation is the result of a receptive endometrium, a functional embryo at the blastocyst stage and a synchronized dialog between maternal and embryonic tissues. Successful implantation requires the endometrium to undergo steroid-dependent change during each menstrual cycle, exhibiting a short period of embryonic receptivity known as the window of implantation. The term "endometrial receptivity" was introduced to define the state of the endometrium during the window of implantation. It refers to the ability of the endometrium to undergo changes that will allow the blastocyst to attach, penetrate, and induce localized changes in the endometrial stroma. These changes are metabolically demanding, and glucose metabolism has been proven to be important for the preparation of the endometrium for embryo implantation. Obesity and polycystic ovary syndrome (PCOS) represent 2 common metabolic disorders that are associated with subfertility. The aim of this review is to summarize the effect of obesity and PCOS on endometrial receptivity at the time of implantation. Focus will be on metabolic alterations that regulate decidualization, including glucose metabolism, hyperinsulinemia, and hyperandrogenism.

Higher circulating leukocytes in women with PCOS is reversed by aerobic exercise

Polycystic ovary syndrome (PCOS) is characterized by insulin resistance, elevated circulating leukocytes, and hypothesized to have higher adipose tissue inflammation. Aerobic exercise reduces circulating leukocytes and improves insulin sensitivity in obese individuals, but the effect of exercise on inflammation in PCOS is not known. We investigated circulating leukocytes, insulin sensitivity by euglycemic-hyperinsulinemic clamp, serum pro- and anti-inflammatory markers (hsCRP, TNF-α, total and high molecular weight adiponectin), and abdominal subcutaneous adipose tissue (SAT) gene expression of proinflammatory markers in 8 PCOS women and 8 obese control females matched for BMI. Additionally, in a prospective study, the 8 women with PCOS underwent a 16-week aerobic exercise regimen with the same measures performed post-intervention. Compared to controls, white blood cell counts (WBC) were 30% higher (p = 0.04) and circulating total adiponectin levels were 150% lower (p = 0.03) in women with PCOS at baseline/pre-exercise conditions. SAT gene expression of macrophage migration inhibitory factor (MIF, p < 0.01) and interleukin-6 (IL-6, p < 0.05) were also lower in women with PCOS. In response to 16 weeks of aerobic exercise, insulin sensitivity improved (p < 0.01) and WBC counts decreased (p = 0.02). The exercise-induced change in WBC and circulating neutrophils correlated inversely with changes in glucose disposal rate (r = -0.73, p = 0.03; and r = -0.82, p = 0.01, respectively). Aerobic exercise reduced serum leptin (p < 0.05) after 4 weeks, trended to reduce the ratio of leptin-to-high molecular weight adiponectin (p < 0.1) by the 8th week, and significantly increased serum dehydroepiandrosterone sulfate (DHEA-S, p < 0.001) after 16 weeks. In conclusion, women with PCOS have higher circulating leukocytes compared to controls, which can be reversed by aerobic exercise and is associated with improvements in insulin sensitivity.

Gene expression in subcutaneous adipose tissue differs in women with polycystic ovary syndrome and controls matched pair-wise for age, body weight, and body mass index

Adipose tissue dysfunction may be a central factor in the pathogenesis of insulin resistance in women with polycystic ovary syndrome (PCOS). Gene expression in subcutaneous adipose tissue in PCOS and its relation to metabolic and endocrine features of the syndrome have been fragmentarily investigated. The aim was to assess in subcutaneous adipose tissue the expression of genes potentially associated with adipose tissue dysfunction and to explore their relation to features of the syndrome. Twenty-one women with PCOS (body mass index [BMI] 18.2–33.4 kg/m²) and 21 controls (BMI 19.2–31.7 kg/m²) were matched pair-wise for age, body weight, and BMI. Tissue biopsies were obtained to measure mRNA expression of 44 genes (TaqMan Low Density Array). Differential expression levels were correlated with BMI, glucose infusion rate (GIR), sex hormone binding globulin (SHBG), and sex steroids. In PCOS, expression of adiponectin receptor 2 (ADIPOR2), LPL, and twist-related protein 1 (TWIST1) was decreased, while expression of chemokine (C-C motif) ligand 2 (CCL2) and heme oxygenase (decycling 1) (HMOX1) was increased. TWIST1 and HMOX1, both novel adipokines, correlated with BMI and GIR. After BMI adjustment, LPL and ADIPOR2 expression correlated with plasma estradiol, and CCL2 expression correlated with GIR, in all women. We conclude that adipose tissue mRNA expression differed in PCOS women and controls and that two novel adipokines, TWIST1 and HMOX1, together with adiponectin, LPL, and CCL2, and their downstream pathways merit further investigation.

Implications of adiponectin in linking metabolism to testicular function

Obesity is a major health problem, contributing to the development of various diseases with aging. In humans, obesity has been associated with reduced testosterone production and subfertility. Adipose tissue is an important source of hormones having influences on both metabolism and reproduction. Among them, the production and secretion of adiponectin is inversely correlated to the severity of obesity. The purpose of this review of literature is to present the current state of knowledge on adiponectin research to determine whether this hormone affects reproduction in men. Surprisingly, evidences show negative influences of adiponectin on GnRH secretion from the hypothalamus, LH and FSH secretion from the pituitary and testosterone at the testicular level. Thus far, the involvement of adiponectin in the influence of metabolism on reproduction in men is limited. However, adiponectin and its receptors are expressed by different cell types of the male gonad, including Leydig cells, spermatozoa, and epididymis. In addition, actions of adiponectin at the testicular level have been shown to promote spermatogenesis and sperm maturation. Therefore, autocrine/paracrine actions of adiponectin in the testis may contribute to support male reproductive function.

Childhood obesity and its impact on the development of adolescent PCOS

Obesity exacerbates the reproductive and metabolic manifestations of polycystic ovary syndrome (PCOS). The symptoms of PCOS often begin in adolescence, and the rising prevalence of peripubertal obesity has prompted concern that the prevalence and severity of adolescent PCOS is increasing in parallel. Recent data have disclosed a high prevalence of hyperandrogenemia among peripubertal adolescents with obesity, suggesting that such girls are indeed at risk for developing PCOS. Obesity may impact the risk of PCOS via insulin resistance and compensatory hyperinsulinemia, which augments ovarian/adrenal androgen production and suppresses sex hormone-binding globulin (SHBG), thereby increasing androgen bioavailability. Altered luteinizing hormone (LH) secretion plays an important role in the pathophysiology of PCOS, and although obesity is generally associated with relative reductions of LH, higher LH appears to be the best predictor of increased free testosterone among peripubertal girls with obesity. Other potential mechanisms of obesity-associated hyperandrogenemia include enhanced androgen production in an expanded fat mass and potential effects of abnormal adipokine/cytokine levels. Adolescents with PCOS are at risk for comorbidities such as metabolic syndrome and impaired glucose tolerance, and concomitant obesity compounds these risks. For all of these reasons, weight loss represents an important therapeutic target in obese adolescents with PCOS.

Association between circulating adiponectin levels and polycystic ovarian syndrome

Background

Low adiponectin levels in polycystic ovarian syndrome (PCOS) have been largely attributed to obesity which is common among these patients. In addition, evidence also suggests that low adiponectin in PCOS may be related to insulin resistance (IR) in these women. However, studies on the role of adiponectin in younger and lean patients are limited. Therefore, the aim of the present study was to examine the association of adiponectin levels in young and lean women with PCOS.

Methods

A case–control study was conducted at the Dow University of Health Sciences, Karachi, Pakistan. Cases were 75 patients of PCOS with Body Mass Index (BMI) &23 aged 16–35 years and 75 healthy age and BMI matched controls were selected from family and friends of the cases. Demographic details, family history and past medical history were obtained through interview by a physician. Anthropometric measurements included weight and height of the participants. Fasting glucose, total cholesterol, high-density lipoprotein (HDL), insulin, adiponectin, and androgen levels were determined. IR was calculated using homeostasis model assessment for insulin resistance (HOMA-IR). Logistic regression models were used to assess the association between adiponectin and PCOS after adjusting for co-variates.

Results

On multivariable analysis, PCOS cases were 3.2 times more likely to have low adiponectin level (OR = 3.2, 95% CI 1.49-6.90, p-value 0.003) compared to the controls after adjustment for age, BMI, family history, marital status, total cholesterol, HDL level and IR. Females with a family history of PCOS were significantly more likely to have lower adiponectin (OR = 3.32, 95% CI 1.27-8.67, p-value 0.014) compared to those who did not have a family history of PCOS. The associations of IR and family history with low adiponectin level also remained statistically significant after adjustments for covariates.

Conclusion

Serum adiponectin levels are independently associated with PCOS and are only partly explained by IR. Adiponectin level may serve as a potential independent biomarker for diagnosis of PCOS in young and lean women with fewer symptoms, or women with a family history of PCOS.

Maternal characteristics and pregnancy outcomes after assisted reproductive technology by infertility diagnosis: ovulatory dysfunction versus tubal obstruction

OBJECTIVE

To examine differences in maternal characteristics and pregnancy outcomes between women with ovulatory dysfunction (OD) and women with tubal obstruction (TO) who underwent assisted reproductive technology (ART).

DESIGN

Retrospective cohort study.

SETTING

Centers for Disease Control and Prevention.

PATIENT(S)

Exposed and nonexposed groups were selected from the 2000-2006 National ART Surveillance System linked with live-birth certificates from three states: Florida, Massachusetts, and Michigan.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Maternal characteristics and pregnancy outcomes, including newborn's health status right after delivery (Apgar score, <7 vs. ≥ 7) as the study outcome of interest, were assessed among women with OD/polycystic ovary syndrome (PCOS) and TO who used ART.

RESULT(S)

A significantly higher prevalence of women with OD/PCOS were younger (<35 years of age; 65.7% vs. 48.9%), were white (85.4% vs. 74.4%), had higher education (29.4% vs. 15.6%), and experienced diabetes (8.8% vs. 5.3%) compared with those having TO. The odds of having a lower (<7) Apgar score at 5 minutes were almost twice as high among newborns of women with OD/PCOS compared with those with TO (crude odds ratio, 1.86; 95% confidence interval [CI], 1.31, 2.64; adjusted odds ratio, 1.90; 95% CI, 1.30, 2.77).

CONCLUSION(S)

Women with OD/PCOS who underwent ART have different characteristics and health issues (higher prevalence of diabetes) and infant outcomes (lower Apgar score) compared with women with TO.

Management of reproduction and pregnancy complications in maternal obesity: which role for dietary polyphenols?

Obesity is a global and dramatic public health problem; maternal obesity represents one of the main risk factors of infertility and pregnancy complications as it is associated with adverse maternal and offspring outcomes. In the last few years, adipose tissue dysfunction associated with altered adipocytokine secretion has been suggested to play a critical role in all the phases of reproductive process. Obesity is a nutrition-related disorder. In this regard, dietary intervention strategies, such as high intake of fruit and vegetables, have shown significant effects in both preserving health and counteracting obesity-associated diseases. Evidence has been provided that polyphenols, important constituents of plant-derived food, can influence developmental program of oocyte and embryo, as well as pregnancy progression by modulating several cellular pathways. This review will examine the controversial results so far obtained on adipocytokine involvement in fertility impairment and pregnancy complications. Furthermore, the different effects exerted by polyphenols on oocyte, embryo, and pregnancy development will be also taken in account.

Effects of upregulation of Hsp27 expression on oocyte development and maturation derived from polycystic ovary syndrome

Heat shock protein 27 (Hsp27) is a heat shock protein family member which can inhibit apoptosis. Our previous studies reported down-regulated Hsp27 in ovarian tissue derived from women with polycystic ovary syndrome (PCOS) however, the exact effect of Hsp27 on oocyte maturation and developmental competence in PCOS is unclear. The effect of Hsp27 over-expression was studied in vitro using oocytes derived from PCOS patients. An artificial GFP-plasmid was injected into human oocyte to increase Hsp27 protein level. Oocyte maturation was evaluated by morphological observation. Mature oocytes were fertilized by intracytoplasmic sperm injection (ICSI) and embryonic developmental competence was evaluated. Critical apoptotic factors and cytokines were measured at both the mRNA and protein level. Our results revealed that Overexpression of HSP27 lowered the maturation rate of oocytes derived from PCOS patients. Meanwhile, fertilization rate and high quality embryo rate were similar between the Hsp27 overexpressing group and controls; however, the blastocyst formation rate in this group was significantly higher than control. Expression analysis revealed that the oocyte-secreted factors, BMP15 and GDF9, and the apoptotic-related regulators, Caspase 3, 8 and 9, were all significantly decreased in Hsp27 overexpressing oocytes. In conclusion, upregulation of Hsp27 inhibits oocyte maturation from PCOS patients, but improves embryonic developmental potential.

Serum concentrations of fibroblast growth factors 19 and 21 in women with gestational diabetes mellitus: association with insulin resistance, adiponectin, and polycystic ovary syndrome history

BACKGROUND

Fibroblast growth factor 19 (FGF19) and FGF21 are considered to be novel adipokines that improve glucose tolerance and insulin sensitivity. In the current study, we investigated serum FGF19 and FGF21 levels in patients with gestational diabetes mellitus (GDM) and explored their relationships with anthropometric and endocrine parameters.

METHOD

Serum FGF19 and FGF21 levels were determined by enzyme-linked immunosorbent assay (ELISA) in patients with GDM (n = 30) and healthy pregnant controls (n = 60) matched for maternal and gestational age. Serum FGF19 and FGF21 levels were correlated with anthropometric, metabolic, and endocrine parameters.

RESULTS

Circulating levels of FGF19 were significantly reduced in patients with GDM relative to healthy pregnant subjects, whereas FGF21 levels were increased in GDM patients. Serum FGF19 levels independently and inversely correlated with insulin resistance (increased homeostasis model assessment of insulin resistance, HOMA-IR) and were positively related to serum adiponectin in both groups. In contrast, serum FGF21 levels independently and positively correlated with insulin resistance and serum triglycerides and were inversely related to serum adiponectin. In addition, in the combined population of both groups, those women with preconception polycystic ovary syndrome (PCOS) history had the lowest levels of FGF19, which were significantly lower than those in GDM patients without PCOS history and those in controls without PCOS history.

CONCLUSIONS

Circulating FGF19 levels are reduced in GDM patients, in contrast with FGF21 levels. Both serum FGF19 and FGF21 levels are strongly related to insulin resistance and serum levels of adiponectin. Considering the different situation between FGF19 and FGF21, we suggest that reduced serum FGF19 levels could be involved in the pathophysiology of GDM, while increased serum FGF21 levels could be in a compensatory response to this disease.

The relationship between gut and adipose hormones, and reproduction

BACKGROUND

Reproductive function is tightly regulated by nutritional status. Indeed, it has been well described that undernutrition or obesity can lead to subfertility or infertility in humans. The common regulatory pathways which control energy homeostasis and reproductive function have, to date, been poorly understood due to limited studies or inconclusive data. However, gut hormones and adipose tissue hormones have recently emerged as potential regulators of both energy homeostasis and reproductive function.

METHODS

A PubMed search was performed using keywords related to gut and adipose hormones and associated with keywords related to reproduction.

RESULTS

Currently available evidence that gut (ghrelin, obestatin, insulin, peptide YY, glucagon-like peptide-1, glucose-dependent insulinotropic peptide, oxyntomodulin, cholecystokinin) and adipose hormones (leptin, adiponectin, resistin, omentin, chemerin) interact with the reproductive axis is presented. The extent, site and direction of their effects on the reproductive axis are variable and also vary depending on species, sex and pubertal stage.

CONCLUSIONS

Gut and adipose hormones interact with the reproductive axis as well as with each other. While leptin and insulin have stimulatory effects and ghrelin has inhibitory effects on hypothalamic GnRH secretion, there is increasing evidence for their roles in other sites of the reproductive axis as well as evidence for the roles of other gut and adipose hormones in the complex interplay between nutrition and reproduction. As our understanding improves, so will our ability to identify and design novel therapeutic options for reproductive disorders and accompanying metabolic disorders.

Polycystic ovaries - beyond menopause

Polycystic ovarian syndrome (PCOS) is the most common endocrine disorder in the reproductive age group; it is characterized by oligo-ovulation or anovulation, hyperandrogenism and the presence of polycystic ovaries. It affects 8-10% of women in the reproductive age group and its main presentations are irregular periods, hirsutism and infertility in this group. Women with PCOS have impaired glucose tolerance, dyslipidemia, and increased risk of type 2 diabetes and metabolic syndrome. The phenotype of PCOS in menopausal women is difficult to define. Studies have included previous history of oligomenorrhea, infertility and hyperandrogenism (clinical or biochemical) to describe the phenotype for postmenopausal women. Hyperandrogenism seen in PCOS women persists after the menopausal transition. Similarly, PCOS women continue to manifest the metabolic alterations such as insulin resistance after menopause, which makes them more susceptible to type 2 diabetes mellitus. The metabolic syndrome occurs more often in women with PCOS and has been shown to be associated with increased risk of cardiovascular disease. Whether PCOS itself causes an increased cardiovascular disease risk later in life is still uncertain. This dilemma needs to be solved since young women with PCOS may be required to undergo expensive investigations and screening for cardiovascular disease, whilst their true disease risk is still unknown.

Role of adiponectin and its receptor in prediction of reproductive outcome of metformin treatment in patients with polycystic ovarian syndrome

AIMS

The aim of this study was to examine the effect of metformin on serum adiponectin and adiponectin receptor-1 (AdipoR1) and evaluate their role in prediction of ovulation in patients with polycystic ovarian syndrome (PCOS).

MATERIAL AND METHODS

The study cohort included 68 PCOS patients with clomiphene citrate resistance (group 1) and 28 healthy women as controls (group 2). Baseline serum adiponectin, AdipoR1, total testosterone (T), and homeostasis model of insulin resistance (HOMA-IR) were measured in all participants. Group 1 received metformin (1500 mg/day) for 6 months followed by second blood sampling.

RESULTS

Group 1 had significantly lower baseline adiponectin and AdipoR1 (P = 0.001) compared to group 2. During treatment, metformin resulted in conception in 5/68 (7%), ovulation in 33/68 (48%) and regular cycles in 41/68 (60%) patients. Group 1 showed post-metformin higher adiponectin and AdipoR1 (P = 0.01) and lower HOMA-IR (P = 0.006) and T (P = 0.001) compared to pre-treatment levels. Post-metformin ovulatory patients had higher adiponectin and AdipoR1 and lower HOMA-IR and T compared to anovulatory patients. Multivariate regression analysis in group 1 showed that only T and HOMA-IR were significant independent factors for predicting ovulatory cycles during metformin treatment (P = 0.04 and P = 0.05, respectively).

CONCLUSIONS

Metformin treatment enhances both adiponectin activity and insulin sensitivity, resulting in a less hyperandrogenic state in patients with PCOS. Serum adiponectin and AdipoR1 are poor predictors of ovulatory outcome during treatment.

Adipocyte biology in polycystic ovary syndrome

Polycystic Ovary Syndrome (PCOS) is a common endocrinopathy that is associated with an adverse metabolic profile including insulin resistance. There is a clear association between obesity, the development of PCOS and the severity of its phenotypic, biochemical and metabolic features. Evidence to support this link includes data from epidemiological, pathophysiological and genetic studies. Given the importance of obesity in the development and manifestation of PCOS, ongoing research into the many facets of adipocyte biology in women with the condition is important and should continue to be a priority. In this review article, we discuss the existing literature on fat distribution, adipokines, adipocyte hypertrophy and adipocyte steroid metabolism in women with PCOS.

Adipokines, insulin-like growth factor binding protein-3 levels, and insulin sensitivity in women with polycystic ovary syndrome

BACKGROUND/AIMS

Many women with polycystic ovary syndrome (PCOS) exhibit insulin resistance. Adipose tissue plays an important role in insulin resistance, and adipokines including tumor necrosis factor (TNF)-α and adiponectin are altered in PCOS. Insulin-like growth factor binding protein-3 (IGFBP-3), alone or in conjunction with other adipokines, is also associated with insulin resistance. We evaluated the effects of TNF-α, adiponectin, and IGFBP-3 on insulin sensitivity and the relationships among these proteins in women with PCOS.

METHODS

We recruited 40 women with PCOS and 40 age- and body mass index (BMI)-matched regular cycling women (controls). The women were divided into obese (BMI ≥ 25 kg/m(2)) and nonobese (BMI < 25 kg/m(2)) groups. Anthropometric measurements were performed, and serum levels of TNF-α, adiponectin, and IGFBP-3 were determined. Insulin sensitivity was estimated using the metabolic clearance rate (MCR) of glucose calculated from the oral glucose tolerance test.

RESULTS

Serum levels of TNF-α and IGFBP-3 did not differ between the PCOS and control groups, but adiponectin levels in the PCOS group were lower than those in control women in the nonobese group (p < 0.05). TNF-α, adiponectin, and IGFBP-3 levels were not correlated with each other in women with PCOS, but a significant positive correlation was observed between adiponectin levels and MCR (p < 0.05). Multiple regression analysis revealed that adiponectin levels were significantly associated with insulin sensitivity (p < 0.05) in women with PCOS.

CONCLUSIONS

IGFBP-3 and TNF-α levels were not associated with insulin sensitivity, but adiponectin levels were related to insulin sensitivity in women with PCOS.

Effect of a combined estrogen and progesterone oral contraceptive on circulating adipocytokines adiponectin, resistin and DLK-1 in normal and obese female rhesus monkeys

BACKGROUND

Hormonal contraception is the most common medication used by reproductive aged women but there is little understanding of the impact of hormonal contraception on obesity and metabolism. Adipokine levels (adiponectin, resistin) and markers of adipocyte development (DLK-1) are altered in obese animals and humans and are associated with increased cardiovascular risk. We sought to determine the effect of combined hormonal oral contraceptive pills (COCs) on circulating adiponectin, resistin and DLK-1 levels in obese and normal-weight rhesus macaque monkeys.

METHODS

Serum adiponectin, resistin and DLK-1 levels in reproductive-age female rhesus macaques of normal (n = 5, mean = 5.76 kg) and inherently obese (n = 5, mean = 8.11 kg) weight were determined before, during and 2 months after cessation of 8 months of continuous treatment with COCs.

RESULTS

The obese group alone showed a significant decrease (p<.01) in weight with COC use, which returned to baseline after COC cessation. Baseline adiponectin levels prior to COC treatment were lower in the obese group (p<.05). Adiponectin levels increased from baseline in both groups, but more so in the obese group (p<.05). Resistin levels were similar at baseline, with an increase in both groups following treatment. Circulating resistin remained elevated above baseline levels after COC cessation, particularly in the obese group (p<.05). While DLK-1 levels did not change significantly in either group, a trend for higher levels in obese animals was observed.

CONCLUSIONS

COC use may alter metabolic processes via direct (resistin) or indirect (adiponectin) means, while unchanging DLK1 levels suggest they do not affect adipocyte development. COCs may directly increase resistin levels, as observed in both groups. As adiponectin is inversely related to adipocyte mass, increased levels in the obese group are likely attributed to weight loss.

Prevalence of polycystic ovary syndrome in women in China: a large community-based study

STUDY QUESTION

What is the prevalence of polycystic ovary syndrome (PCOS) in Han Chinese women from different communities?

SUMMARY ANSWER

The prevalence of PCOS in Chinese women aged 19-45 years is 5.6%.

WHAT IS KNOWN ALREADY

The prevalence of PCOS is reported to range from 5 to 10% but to the best of our knowledge the Han Chinese population has not been studied.

STUDY DESIGN, SIZE, DURATION

A large-scale epidemiological study was carried out between October 2007 and September 2011 in 15 924 Han Chinese women of reproductive age (19-45 years) from the 10 provinces and municipalities in China.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A total of 16 886 women from 152 cities and 112 villages were involved in the study. All study participants received a questionnaire and underwent a physical and transvaginal ultrasound examination. Blood samples were collected from a subsample of women (n = 3565) for analysis of metabolic markers and hormones. Based on the Rotterdam PCOS criteria, we assessed hyperandrogenism (H), chronic anovulation (O) and polycystic ovaries (P). Following diagnosis, women with PCOS were assigned to one of four different phenotypes. Finally, the prevalence and related risks of PCOS among Chinese women were estimated based on all the data sources.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 16 886 women were initially involved in the study and 15 924 eligible participants then completed the study; the overall response rate was 94.3% (15 924/16 886). The prevalence of PCOS in the Chinese community population was 5.6% (894/15 924). Blood samples were analyzed from 833 of these women who were assigned to the four PCOS phenotypes as follows: 19% H + O, 37% H + P, 15% O + P and 29% H + O + P. Comparing the 833 women with PCOS to 2732 women without PCOS indicated that PCOS occurs in younger women (P < 0.05) and these women were prone not only to menstrual problems, hyperandrogenism, PCO and infertility but also metabolic syndrome (MS) and insulin resistance (IR). However, there was no significant difference in the rate of hypertension or hyperlipemia between the two groups. Obese patients with PCOS had a higher rate of MS (16 versus 48%), IR (7 versus 28%), hypertension (8 versus 30%) and hyperlipemia (48 versus 73%) compared with non-obese patients (all P < 0.05), respectively. The rates of metabolic complications in patients with PCOS increased with age.

LIMITATIONS, REASONS FOR CAUTION

Age and ethnic origin contribute to the differing manifestations of PCOS; therefore, sampling is one of the most important issues in epidemiological research into PCOS. Owing to the mobility of the Chinese population, the survey among resident populations caused a certain deviation in the age distribution.

WIDER IMPLICATIONS OF THE FINDINGS

The prevention and treatment of PCOS, particularly in those who are obese, are essential in Chinese women of reproductive age.

Activation of the LH receptor up regulates the type 2 adiponectin receptor in human granulosa cells

PURPOSE

Adiponectin is a predominantly adipocyte-derived hormone which influences insulin sensitivity and energy homeostasis through at least two receptors, AdipoR1 and AdipoR2. In animal models, adiponectin may regulate ovarian steroidogenesis, folliculogenesis, and ovulation. The receptors AdipoR1 and AdipoR2 are present in the human ovary, but their regulation is unknown. In these studies, we determined the effects of LH receptor activation on the expression and function of the two adiponectin receptors in human granulosa cells.

METHODS

Granulosa cells were obtained at the time of oocyte retrieval in women undergoing in vitro fertilization (IVF). Cells were isolated and cultured for 48 h in DMEM/F12 medium with 5 % FBS and 50 ug/ml gentamicin. Medium was changed to low serum for 12 h and cells were treated with hCG (100 ng/ml), forskolin (30 μMol/L), or FSH (1 IU/ml) for 24 h for mRNA experiments. mRNA was isolated and RT PCR was performed using Taqman assays and quantification with the delta delta CT method. For immunocytochemistry, cells were grown on chamber slides and treated with hCG for 1 to 24 h and fixed with acetone. ICC was performed with polyclonal rabbit primary antibodies followed by alexa fluor goat anti-rabbit antibody and imaging with a fluorescence microscope and Zeiss software analysis. 3β-hydroxysteroid dehydrogenase (3βHSD) enzyme activity was determined by measuring the progesterone produced when cells were provided with an excess of 22-hydroxy-cholesterol as substrate following an incubation with hCG (1 IU/ml) and/or adiponectin (10 ng/ml). Progesterone content in the media was determined by ELISA.

RESULTS

Messenger RNA for the two Adiponectin receptors is differentially regulated by activation of LHR with hCG treatment. AdipoR2 was increased nearly 4-fold (p < 0.05), whereas AdipoR1 expression was not changed by hCG treatment. Treatment with either FSH or forskolin (an activator of cAMP) had similar effects. Basal AdipoR2 protein was fairly low in granulosa cells in culture however treatment of cells with hCG resulted in a discernible increase in immunodetectable cytoplasmic protein as early as 6 h after treatment and was maintained for at least 24 h. The number of cells positive for AdipoR2 at 6 h increased from a basal of 20 % to almost 60 % (p < 0.05). Adiponectin treatment of hCG-primed cells resulted in increased 3βHSD activity by approximately 60 % over hCG alone and more than 3-fold over basal levels.

CONCLUSIONS

AdipoR2 is regulated by the LH receptor function via a cAMP dependant mechanism. Increased expression of adipoR2 prior to and following ovulation may contribute to enhanced 3βHSD activity and increased progesterone secretion by the corpus luteum of the ovary. Dysregulation of adiponectin that may occur with PCOS may impair normal progesterone production.

Molecular signature of adipose tissue in patients with both non-alcoholic fatty liver disease (NAFLD) and polycystic ovarian syndrome (PCOS)

Background

Polycystic ovarian syndrome (PCOS) is one of the most common reproductive disorders with strong association with both insulin resistance and non-alcoholic fatty liver disease (NAFLD). To untangle the complex relationship between PCOS and NAFLD, we analyzed serum biomarkers of apoptosis, some adipokines and mRNA profiles in the visceral adipose tissue of obese patients with NAFLD who were also diagnosed with PCOS and compared to a group with NAFLD only.

Methods

We included patients with biopsy-proven NAFLD and PCOS (N = 12) and BMI-matched biopsy-proven NAFLD patients without PCOS (N = 12). Expression levels of individual mRNAs and soluble serum biomarkers were compared by non-parametric Mann–Whitney test. The analysis also included Spearman rank correlation tests and multiple regression analysis. For co-correlated genes, the factor analysis was performed.

Results

The total serum levels of apoptotic biomarker M30 were significantly elevated in PCOS patients with liver steatosis as compared to non-PCOS NAFLD controls (P < 0.02), pointing that androgen-dependent proapoptotic PCOS environment that may directly contribute to NAFLD progression in these patients. Similarly, hyperandrogenism may explain the observed PCOS-specific decrease (P < 0.04) in adipose LDLR mRNA expression that may be connected to the proneness of PCOS patients to NAFLD. The levels of mRNA encoding angiogenesis-associated GSK-3B interacting protein ninein were also significantly increased in the adipose tissue of NAFLD patients with PCOS (P < 0.007). Furthermore, the levels of resistin positively correlated with expression levels of LDLR and prothrombin time (PT).

Conclusion

An androgen-dependent proapoptotic PCOS environment may directly contribute to NAFLD progression in these patients. Hyperandrogenism may explain an observed decrease in adipose LDLR mRNA expression. An inflammation-associated increase in the release of resistin into circulation might contribute to the prothrombotic state observed under conditions associated with insulin resistance, including PCOS. The studies of larger cohorts of NAFLD with and without PCOS patients are needed to further assess these potential interactions.

Adipokines in reproductive function: a link between obesity and polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy associated with infertility and metabolic disorder in women of reproductive age. Dysfunction of adipose tissue has been implicated in the pathophysiology of PCOS. Increasing evidence shows that the dysregulated expression of adipokines, the secreted products of adipose tissue, plays an important role in the pathology of PCOS. Here, we review the role of several identified adipokines that may act as a link between obesity and PCOS. PCOS also reciprocally influences the profile of adipokines. Insight into the underlying mechanisms will help better understand the pathology of PCOS and identify new therapeutic targets of this syndrome.

The complex interaction between obesity, metabolic syndrome and reproductive axis: a narrative review

The aim of this narrative review is to provide current evidence for the interaction between obesity, metabolic syndrome (MS) and reproductive axis. Gonadotropin-releasing hormone (GnRH) pulses and, consequently, normal function of reproductive (hypothalamus-pituitary-gonadal) axis depend on normal energy balance, which presupposes sufficient food intake, reasonable energy consumption and average thermoregulatory costs. In case of an energy imbalance, reproductive dysfunction may occur. In young women, excessive leanness is accompanied by puberty delay, whereas premature puberty might be a manifestation of obesity. In a similar way, obesity in men affects fertility. Excess adipose tissue results in increased conversion of testosterone to estradiol, which may lead to secondary hypogonadism through reproductive axis suppression. Moreover, oxidative stress at the level of the testicular micro-environment may result in decreased spermatogenesis and sperm damage. Products of the adipocyte, such as leptin, adiponectin and resistin, and gut peptides, such as ghrelin, are considered to be crucial in the interaction between energy balance and reproduction. Finally, an indirect evidence for the interplay between MS and reproductive axis is the fact that when treating components of one, parameters of the other can be improved as well. These therapeutic interventions include lifestyle modifications, pharmacological agents, such as sex hormone replacement therapy, and surgical procedures. Although many issues remain unclear, the elucidation of the complex interaction between MS and reproductive axis will have obvious clinical implications in the therapeutic approach of both entities.

Associations of testosterone and sex hormone binding globulin with adipose tissue hormones in midlife women

OBJECTIVE

Regulators of adipose tissue hormones remain incompletely understood, but may include sex hormones. As adipose tissue hormones have been shown to contribute to numerous metabolic and cardiovascular disorders, understanding their regulation in midlife women is of clinical importance. Therefore, we assessed the associations between testosterone (T) and sex hormone binding globulin (SHBG) with leptin, high molecular weight (HMW) adiponectin, and the soluble form of the leptin receptor (sOB-R) in healthy midlife women.

DESIGN AND METHODS

Cross-sectional analyses were performed using data from 1,881 midlife women (average age 52.6 (±2.7) years) attending the sixth Annual follow-up visit of the multiethnic Study of Women's Health Across the Nation.

RESULTS

T was weakly negatively associated with both HMW adiponectin and sOB-R (r = -0.12 and r = -0.10, respectively; P < 0.001 for both), and positively associated with leptin (r = 0.17; P < 0.001). SHBG was more strongly and positively associated with both HMW adiponectin and sOB-R (r = 0.29 and r = 0.24, respectively; P < 0.001 for both), and more strongly and negatively associated with leptin (r = -0.27; P < 0.001). Adjustment for fat mass, insulin resistance, or waist circumference only partially diminished associations with HMW adiponectin and sOB-R, but attenuated associations with leptin. In conclusion, in these midlife women, lower SHBG values, and to a lesser extent, higher T levels, were associated with lower, or less favorable, levels of adiponectin and sOB-R, independent of fat mass.

CONCLUSIONS

These data suggest that variation in these adipose hormones resulting from lower SHBG levels, and possibly, though less likely, greater androgenicity, may contribute to susceptibility for metabolic and cardiovascular outcomes during midlife in women.

Is the polycystic ovary syndrome the causative of the increase in inflammatory markers and metabolic risk?

AIMS

To investigate the relationship between the levels of C-reactive protein (CRP), interleukin-6 (IL-6) and IL-1β and the hormonal and metabolic alterations in women with polycystic ovary syndrome (PCO).

MATERIALS AND METHODS

Case-control study. CRP, IL-6 and IL-1β were evaluated in combination with obesity, insulin resistance (IR) and hyperandrogenism parameters in 20 patients with PCO. Twenty healthy women were used as the control.

RESULTS

The average CRP values was 5.1 in the cases vs. 0.8 mg/L in the control group (p < 0.0001). The IL-6 average values were 2.77 in the cases vs. 2.70 pg/ml in the control group (p = 0.254). IL-1β levels were found to be within the normal range in all individuals. A positive correlation was found between the CRP values and the IR (p < 0.0001) as well as with the presence of obesity (p < 0.02). No correlation was found between PCR and hyperandrogenemia (p = 0.4) nor between IL-6 values and IR (p = 0.3), or between the levels of this cytokine and the presence of hyperandrogenemia (p = 0.2). A significant correlation was found between IL-6 levels and obesity (p < 0.0001).

CONCLUSIONS

The present study demonstrates the presence of a chronic inflammation status in young women with PCO. These parameters are mainly related to obesity and, to a lesser extent, to IR.

Factors determining the risk of the metabolic syndrome: is there a central role for adiponectin?

BACKGROUND AND OBJECTIVES

The pathogenesis of the metabolic syndrome (MetS) is not well understood. This review is based on the hypothesis that both traditional and emerging risk factors act through adiponectin.

SUBJECTS AND METHODS

We conducted a search of the literature using prominent electronic databases and search terms that included in combination: adiponectin, diet, dietary patterns, exercise, metabolic rate, MetS and testosterone. Articles were restricted to studies conducted on adult humans, reported in English and within the time period 2000-2012.

RESULTS AND CONCLUSIONS

Both traditional and emerging risk factors associated with the MetS show some evidence of exerting their influence through adiponectin. High-quality randomized controlled trials that alter adiponectin levels are required to further corroborate this hypothesis.

Insulin resistance and the polycystic ovary syndrome revisited: an update on mechanisms and implications

Polycystic ovary syndrome (PCOS) is now recognized as an important metabolic as well as reproductive disorder conferring substantially increased risk for type 2 diabetes. Affected women have marked insulin resistance, independent of obesity. This article summarizes the state of the science since we last reviewed the field in the Endocrine Reviews in 1997. There is general agreement that obese women with PCOS are insulin resistant, but some groups of lean affected women may have normal insulin sensitivity. There is a post-binding defect in receptor signaling likely due to increased receptor and insulin receptor substrate-1 serine phosphorylation that selectively affects metabolic but not mitogenic pathways in classic insulin target tissues and in the ovary. Constitutive activation of serine kinases in the MAPK-ERK pathway may contribute to resistance to insulin's metabolic actions in skeletal muscle. Insulin functions as a co-gonadotropin through its cognate receptor to modulate ovarian steroidogenesis. Genetic disruption of insulin signaling in the brain has indicated that this pathway is important for ovulation and body weight regulation. These insights have been directly translated into a novel therapy for PCOS with insulin-sensitizing drugs. Furthermore, androgens contribute to insulin resistance in PCOS. PCOS may also have developmental origins due to androgen exposure at critical periods or to intrauterine growth restriction. PCOS is a complex genetic disease, and first-degree relatives have reproductive and metabolic phenotypes. Several PCOS genetic susceptibility loci have been mapped and replicated. Some of the same susceptibility genes contribute to disease risk in Chinese and European PCOS populations, suggesting that PCOS is an ancient trait.

Metabolic profiles characterizing different phenotypes of polycystic ovary syndrome: plasma metabolomics analysis

BACKGROUND

Polycystic ovary syndrome (PCOS) is a heterogeneous endocrine disorder accompanied with an increased risk of developing type 2 diabetes mellitus and cardiovascular disease; despite being a common condition, the pathogenesis of PCOS remains unclear. Our aim was to investigate the potential metabolic profiles for different phenotypes of PCOS, as well as for the early prognosis of complications.

METHODS

A total of 217 women with PCOS and 48 healthy women as normal controls were studied. Plasma samples of subjects were tested using two different analytical platforms of metabolomics: 1H nuclear magnetic resonance (NMR) and gas chromatography/time-of-flight mass spectrometry (GC/TOF-MS).

RESULTS

Our results showed that carbohydrate, lipid and amino acid metabolisms were influenced in PCOS. The levels of lactate, long-chain fatty acids, triglyceride and very low-density lipoprotein were elevated, while glucose, phosphatidylcholine and high-density lipoprotein (HDL) concentrations were reduced in PCOS patients as compared with controls. Additionally, the levels of alanine, valine, serine, threonine, ornithine, phenylalanine, tyrosine and tryptophan were generally increased, whereas the levels of glycine and proline were significantly reduced in PCOS samples compared to controls. Furthermore, the ratio of branched-chain amino acid to aromatic amino acid concentrations (BCAA/AAA) in PCOS plasma was significantly reduced in PCOS patients and was insusceptible to obesity and insulin sensitivity.

CONCLUSIONS

Our results suggested that the enhanced glycolysis and inhibited tricarboxylic acid cycle (TAC) in women with PCOS. Decrease of BCAA/AAA ratio was directly correlated with the development of PCOS. Ovulatory dysfunction of PCOS patients was associated with raised production of serine, threonine, phenylalanine, tyrosine and ornithine. Elevated levels of valine and leucine, and decreased concentrations of glycine in PCOS plasma could contribute to insulin sensitivity and could be considered as the potential biomarkers for long-term risk assessment of diabetes mellitus.

Serum asymmetric dimethylarginine, apelin, and tumor necrosis factor-α levels in non-obese women with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is associated with multiple risk factors for cardiovascular disease (CVD), including insulin resistance, type 2 diabetes mellitus, obesity, hypertension, and dyslipidemia. In addition, hyperandrogenism may contribute to the pathogenesis of CVD, independent of obesity and insulin resistance. We investigated serum levels of asymmetric dimethylarginine (ADMA), apelin, and tumor necrosis factor (TNF)-α as CVD risk markers and their relationship with hyperandrogenism in non-obese women with PCOS. In this study were included 82 non-obese women with PCOS and 33 controls. Women with PCOS were further divided into two groups: women with hyperandrogenism (HA-PCOS, n=37) and those without hyperandrogenism (NA-PCOS, n=45). Serum ADMA, apelin, and TNF-α levels were compared among the three groups and their relationship with hyperandrogenism was evaluated. Serum ADMA levels were significantly higher in the HA-PCOS group than in the NA-PCOS and control groups (0.45 ± 0.09 vs. 0.38 ± 0.08 vs. 0.40 ± 0.07; P<0.0005). Serum TNF-α levels were significantly higher among women with PCOS compared with controls (2.91 ± 1.25 vs. 1.74 ± 0.77; P<0.001) and in the HA-PCOS group compared with the NA-PCOS group (3.21 ± 1.24 vs. 2.60 ± 1.24; P<0.0001). Both PCOS groups had significantly lower serum apelin levels compared with controls (1.31 ± 0.54 vs. 1.16 ± 0.34 vs. 2.78 ± 1.10; P<0.0001). ADMA and TNF-α were positively correlated with total testosterone (r=0.219, P=0.022; r=0.332, P<0.001, respectively) and free androgen index (r=0.287, P=0.002; r=0.289, P=0.002, respectively), whereas apelin was negatively correlated with these parameters (r=-0.362, P<0.001; r=-0.251, P=0.008). These findings may indicate that non-obese women with PCOS are at an increased risk for CVD, which is further aggravated by hyperandrogenism.

'Metabolically healthy obesity': origins and implications

When humans eat more and exercise less, they tend to become obese and unhealthy. The molecular pathways that link obesity to serious diseases like Type 2 diabetes and cardiovascular disease have become a subject of intensive scientific investigation because the exploding prevalence of obesity worldwide represents a grave new threat to the health of hundreds of millions of people. However, obesity is not always destiny. Two important clinical populations have been valuable to understand the mechanisms behind this conundrum: individuals who exhibit metabolic dysfunction, diabetes and elevated cardiovascular disease risk despite a lean body type, and individuals who are relatively protected from these dangers despite significant obesity. Study of this second group of 'metabolically healthy obese' people in particular has been revealing because such individuals exhibit specific, identifiable, anatomic, cellular and molecular features that set them apart from the rest of us who suffer declining health with increasing weight. Here, we examine some of these features, including some mouse models that are informative of mechanism, and suggest hypotheses for further study, including the possibility that genes and pathways of the immune system might offer new diagnostic or therapeutic targets.

Associations of adiponectin gene polymorphisms with polycystic ovary syndrome: a meta-analysis

Adiponectin gene polymorphisms have been implicated in polycystic ovary syndrome (PCOS) development. However, results from previous studies were inconsistent and inconclusive. To shed some light on the relationship of two adiponectin gene polymorphisms, T45G and G276T, with PCOS, we conducted the current meta-analysis. PubMed was used for searching all eligible studies up to September 30, 2011. Odds ratio (OR) with the corresponding 95% confidence interval (CI) was adopted to evaluate the strength of the associations. In total, ten case-control studies involving 2,821 participants were included in the meta-analysis. Results showed that the T45G polymorphism was not associated with PCOS for allelic contrast (OR = 1.10, 95%CI: 0.83-1.44, P = 0.514), with evidence of large heterogeneity (P(heterogeneity) = 0.002). Concerning G276T polymorphism, the results showed that the T allele was related to a reduced risk of PCOS compared with the G allele under allelic genetic model (OR = 0.81, 95%CI: 0.70-0.93, P = 0.003), and no significant heterogeneity (P(heterogeneity) = 0.268) was revealed. Similar results were observed under additive, dominant and recessive genetic models for both of these two polymorphisms. No publication bias was detected. Our results suggested that the T45G polymorphism of adiponectin gene was not significantly associated with PCOS, while the G276T polymorphism was related to a decreased risk of PCOS.

The expression of sex steroid synthesis and inactivation enzymes in subcutaneous adipose tissue of PCOS patients

Modulation of sex steroid pre-receptor in adipose tissue is important for the development of metabolic diseases, but its roles in the pathogenesis of polycystic ovary syndrome (PCOS) has not been fully characterized. Herein we compared the expression of key sex steroid converting enzymes in the subcutaneous adipose tissue (SAT) between patients with PCOS and the matched controls. Most of the sex steroid converting enzymes were highly expressed in the SAT, except 17α-hydroxylase (CYP17A1). Compared with the controls, PCOS patients showed significantly higher levels of 3β-hydroxysteroid dehydrogenase1-2 (3β-HSD1-2), aldo-keto reductase 1C 1-3 (AKR1C1-3) and leptin, but lower level of P450 aromatase and 5α-reductase 1. Interestingly, leptin was positively correlated to AKR1C2 expression and negatively to 5α-reductase1 as well as peroxisome proliferator-activated receptor γ (PPARγ). In summary, the expression of enzymes synthesizing testosterone and enzymes inactivating DHT and progesterone was higher in SAT of PCOS patients compared to controls. Correlation analysis indicated that increased leptin expression may be negatively related to local DHT level. These data suggested that sex steroid converting enzymes expression was different in SAT of PCOS patients that might contribute to abnormal testosterone and leptin level of PCOS patients.

Cardiometabolic aspects of the polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder amongst women of reproductive age and is associated with various metabolic perturbations, in addition to chronic anovulation and factors related to androgen excess. In general, women live longer than men and develop cardiovascular disease at an older age. However, women with PCOS, as compared with age- and body mass index-matched women without the syndrome, appear to have a higher risk of insulin resistance, hyperinsulinemia, glucose intolerance, dyslipidemia, and an increased prothrombotic state, possibly resulting in a higher rate of type 2 diabetes mellitus, fatty liver disease, subclinical atherosclerosis, vascular dysfunction, and finally cardiovascular disease and mortality. Further alterations in PCOS include an increased prevalence of sleep apnea, as well as various changes in the secretion and/or function of adipokines, adipose tissue-derived proinflammatory factors and gut hormones, all of them with direct or indirect influences on the complex signaling network that regulates metabolism, insulin sensitivity, and energy homeostasis. Reviews on the cardiometabolic aspects of PCOS are rare, and our knowledge from recent studies is expanding rapidly. Therefore, it is the aim of the present review to discuss and to summarize the current knowledge, focusing on the alterations of cardiometabolic factors in women with PCOS. Further insight into this network of factors may facilitate finding therapeutic targets that should ameliorate not only ovarian dysfunction but also the various cardiometabolic alterations related to the syndrome.

Single-cell expression analysis of BMP15 and GDF9 in mature oocytes and BMPR2 in cumulus cells of women with polycystic ovary syndrome undergoing controlled ovarian hyperstimulation

PURPOSE

To detect expression of bone morphogenetic protein 15 (BMP15) and growth differentiation factor 9 (GDF9) in oocytes, and their receptor type 2 receptor for BMPs (BMPR2) in cumulus cells in women with polycystic ovary syndrome (PCOS) undergoing in vitro fertilization (IVF), and determine if BMPR2, BMP15, and GDF9 expression correlate with hyperandrogenism in FF of PCOS patients.

METHODS

Prospective case-control study. Eighteen MII-oocytes and their respective cumulus cells were obtained from 18 patients with PCOS, and 48 MII-oocytes and cumulus cells (CCs) from 35 controls, both subjected to controlled ovarian hyperstimulation (COH), and follicular fluid (FF) was collected from small (10-14 mm) and large (>18 mm) follicles. RNeasy Micro Kit (Qiagen) was used for RNA extraction and gene expression was quantified in each oocyte individually and in microdissected cumulus cells from cumulus-oocyte complexes retrieved from preovulatory follicles using qRT-PCR. Chemiluminescence and RIA assays were used for hormone assays.

RESULTS

BMP15 and GDF9 expression per oocyte was higher among women with PCOS than the control group. A positive correlation was found between BMPR2 transcripts and hyperandrogenism in FF of PCOS patients. Progesterone values in FF were lower in the PCOS group.

CONCLUSION

We inferred that BMP15 and GDF9 transcript levels increase in mature PCOS oocytes after COH, and might inhibit the progesterone secretion by follicular cells in PCOS follicles, preventing premature luteinization in cumulus cells. BMPR2 expression in PCOS cumulus cells might be regulated by androgens.

Effect of maternal obesity on estrous cyclicity, embryo development and blastocyst gene expression in a mouse model

STUDY QUESTION

Does maternal obesity affect estrous cyclicity, embryo development and blastocyst gene expression in mice?

SUMMARY ANSWER

Maternal obesity alters estrous cyclicity and causes the down-regulation of two key metabolite receptors (Slc2a1 and Ldlr) in blastocysts recovered from diet-induced obese females, but embryo development is not affected.

WHAT IS KNOWN ALREADY

Maternal obesity reduces fertility because of effects in the periconception period, but its negative influence is on estrous cyclicity, oocyte quality or embryo development.

STUDY DESIGN, SIZE AND DURATION

This was a randomized study based on a mouse model for obesity. Twenty-one outbred NIH Swiss mice were used and obesity was induced by a diet high in fat administered for 12 weeks prior to breeding to control males.

MATERIAL, SETTING AND METHODS

Females were fed either a control diet (C, n = 9) or a diet high in fat [diet-induced obesity (DiO), n = 12] for 12 weeks, and were then co-housed with fertile males. Mice that failed to breed during 20 consecutive days were considered infertile. Control and diet-induced obese females that demonstrated vaginal plugs were euthanized 3.5 days after mating, blood was sampled for glucose and hormone measurements, corpora lutea counted and embryos recovered; the relative mRNA abundance of 11 candidate genes was determined in blastocysts by qPCR.

MAIN RESULTS AND THE ROLE OF CHANCE

Five DiO females failed to breed and displayed anovulatory ovaries (DiOI), whereas the other seven DiO females (DiOF) could breed, albeit over an extended period compared with controls. DiOF weighed significantly less than DiOI. Both groups had elevated serum insulin compared with C, although blood glucose level was only significantly higher than that in controls in the infertile DiOI group. Adiponectin was lower in the DiOI and leptin higher in both the DiOI and DiOF mice than in C. DiOF ovulated the same number of oocytes as C, and embryo development to blastocyst was normal. The expression of genes encoding metabolic hormone receptors (Insr, Igf1r, Igf2r, Adipor1, Adipor2 and Lepr) and key metabolic enzymes (Gapdh, Cpt1a and Sod2) did not differ between DiOF and C blastocysts, but that of metabolite receptors (Slc2a1 and Ldr) was down-regulated in DiOF. To limit the role of chance, the experiments were conducted in a defined laboratory setting with the proper controls, and the animals were randomly assigned to each experimental group. Moreover, a P-value of < 0.05 was chosen to determine whether the differences observed between the groups were statistically significant.

LIMITATIONS AND REASONS FOR CAUTION

The results obtained may not fully extrapolate to humans. Also, as follicular activity was not monitored while breeding, so the extended breeding period for DiOF group might be explained by behavioral abnormalities occurring in normal cycling animals.

WIDER IMPLICATIONS OF THE FINDINGS

DiO alters the estrous cycle in the mouse model and demonstrates a role of obesity in infertility. The data also suggest that in an outbred, genetically diverse population, such as the human, individual susceptibility to obesity and associated infertility induced by diet exists. The apparently normal development to blastocyst observed in fertile, obese females suggests that preimplantation embryos can resist potentially adverse outcomes caused by an oversupply of fatty acids and glucose under in vivo conditions. This metabolic plasticity may, in part, be due to an ability to down-regulate metabolite transporters, thereby preventing excessive nutrient uptake.

STUDY FUNDING/COMPETING INTEREST(S)

The research was supported by funds from the University of Missouri, grants from the National Institutes of Health and by a fellowship from the Lalor Foundation. There were no competing interests.

TRIAL REGISTRATION NUMBER

Not applicable.

Serum total adiponectin level and risk of cardiovascular disease in Han Chinese populations: a meta-analysis of 17 case-control studies

OBJECTIVE

To systematically evaluate low serum adiponectin level as a risk factor for cardiovascular disease (CVD). A meta-analysis was performed to quantitatively analyse the association of serum total adiponectin level with CVD using previous case-control studies in Han Chinese populations.

METHODS

Several electronic databases were searched for relevant articles up to July 2011. A total of nine (n = 933), eight (n = 939) articles were included in each meta-analysis regarding the association of serum adiponectin level with coronary heart disease (CHD) and ischaemic stroke, respectively. Publication bias was examined by the Egger's linear regression test. Sensitivity analysis was performed by omitting one study at a time, and the pooled standardized mean difference (SMD) was estimated using fixed-effects model and random-effects model, respectively.

RESULTS

Serum total adiponectin concentrations were lower in patients with CHD and ischaemic stroke, with pooled SMD of -1·41 (95% CI -1·69, -1·12, P < 0·00001) and -1·69 (95% CI -2·04, -1·33, P < 0·00001), respectively. By performing a meta-regression analysis, homeostasis model assessment of insulin resistance, study size, adiponectin measurement assays, gender and mean body mass index of cases failed to account for heterogeneity for comparisons between lower adiponectin level and ischaemic stroke. However, study size had significant effect on the association of lower adiponectin level with CHD and accounted for 96·72% of the between-study variance. No publication bias was detected. No single study was found to affect the overall result of each analysis by sensitivity testing.

CONCLUSIONS

The accumulated evidence suggested that low serum adiponectin level increased the risk of a first cardiovascular event in the Han Chinese population. Further study is recommended with larger sample size to explore the role of hypoadiponectinemia in the causation of CVD.

Steroidogenic regulatory factor FOS is underexpressed in polycystic ovary syndrome (PCOS) adipose tissue and genetically associated with PCOS susceptibility

CONTEXT

Polycystic ovary syndrome (PCOS) is a heterogeneous common genetic disorder characterized by hyperandrogenemia and insulin resistance. Alterations in gene expression profiles of the ovary and adipose tissue identified the candidate gene FBJ murine osteosarcoma viral oncogene homolog (FOS) for further investigation of expression changes in metabolic tissues and genetic studies.

OBJECTIVE

The objective of the study was to confirm the underexpression of the FOS gene in sc adipose and determine whether variants in this gene are risk factors for PCOS.

DESIGN

RT-PCR was performed in sc fat from women with and without PCOS. Genotyping of single-nucleotide polymorphisms in the FOS locus was performed to test for association with PCOS.

SETTING

The study was conducted at a tertiary care academic institution.

PARTICIPANTS

Twenty-two PCOS and 13 control subjects were recruited for gene expression studies. We assembled a discovery genotyping cohort of 354 cases and 161 controls and a replication cohort of 476 cases and 315 controls, all of whom were Caucasian.

MAIN MEASUREMENTS

Gene expression by quantitative real-time RT-PCR, FOS genotype, and PCOS status were measured.

RESULTS

FOS expression was confirmed to be reduced in PCOS adipose tissue. Three single-nucleotide polymorphisms were significantly associated with PCOS in the discovery cohort (rs8006998, P = 0.0031; rs8013918, P = 0.0006; rs8013942, P = 0.0087). rs8006998 was also associated with PCOS in the replication cohort (P = 0.013).

CONCLUSIONS

Differential gene expression in sc fat and genetic association at the FOS locus in PCOS subjects implicates a role for this transcription factor in PCOS. FOS dysfunction may be a common factor between hyperandrogenism and insulin resistance.

Adipocytokine profiles in a putative novel postmenopausal polycystic ovary syndrome (PCOS) phenotype parallel those in premenopausal PCOS: the Rancho Bernardo Study

The objective was to investigate whether the associations between leptin, adiponectin, andadiposity reported in classic polycystic ovary syndrome (PCOS) are also observed in elderly women with a novel putative postmenopausal PCOS phenotype. We studied 713 postmenopausal community-dwelling women. Diagnosis of the novel phenotype required the presence of ≥3 diagnostic features including: 1) a personal history of oligomenorrhea; 2) history of infertility or miscarriage; 3) current or past clinical or hormonal evidence of hyperandrogenism; 4) central obesity; 5) biochemical evidence of insulin resistance. Women in the control group had ≤2 of these components. Mean age (±SD) was 74±8 years for the study cohort. Sixty-six women (9.3%) had the putative PCOS phenotype. Serum leptin was higher (mean 25.70±15.67 vs 14.94+9.89 ng/mL, P<.01) and adiponectin lower (mean 11.72±4.80 vs 17.31±7.45 μg/mL, P<.01) in cases vs controls. Leptin was positively, and adiponectin inversely, associated with an increasing number of phenotype features (P<.01 for linearity). In age-adjusted regression analysis, adjustment for waist circumference eliminated the association between leptin and the PCOS phenotype, but not the association between adiponectin and the PCOS phenotype. In this novel postmenopausal PCOS phenotype, adipocytokine profiles and their associations with adiposity parallel those reported in younger women with classic PCOS. These results support our hypothesis that a putative phenotype analogous to PCOS can be identified in postmenopausal women using clinical and biochemical criteria. Use of this novel phenotype could provide a basis for studies of the delayed consequences of PCOS in older women.

Reproductive and metabolic phenotype of a mouse model of PCOS

Polycystic ovary syndrome (PCOS), the most common endocrine disorder in women in their reproductive age, is characterized by both reproductive and metabolic features. Recent studies in human, nonhuman primates, and sheep suggest that hyperandrogenism plays an important role in the development of PCOS. We investigated whether chronic dihydrotestosterone (DHT) exposure in mice reproduces both features of PCOS. Such a model would allow us to study the mechanism of association between the reproductive and metabolic features in transgenic mice. In this study, prepubertal female mice received a 90 d continuous release pellet containing the nonaromatizable androgen DHT or vehicle. At the end of the treatment period, DHT-treated mice were in continuous anestrous, their ovaries contained an increased number of atretic follicles, with the majority of atretic antral follicles having a cyst-like structure. Chronic DHT-exposed mice had significantly higher body weights (21%) than vehicle-treated mice. In addition, fat depots of DHT-treated mice displayed an increased number of enlarged adipocytes (P < 0.003). Leptin levels were elevated (P < 0.013), adiponectin levels were diminished (P < 0.001), and DHT-treated mice were glucose intolerant (P < 0.001). In conclusion, a mouse model of PCOS has been developed showing reproductive and metabolic characteristics associated with PCOS in women.

Is PCOS an inflammatory process?

PRO--PCOS is associated with low-grade systemic inflammation as evidenced by elevation of multiple markers of inflammation such as C-reactive protein, interleukin-18, monocyte chemoattractant protein-1 and white blood cell count as well as endothelial dysfunction and increased oxidative stress. CON--Current studies examining the evidence for low grade inflammation in PCOS are small, heterogeneous for the diagnosis, confounded by degree of adiposity and do not consistently demonstrate a clinically relevant increase in the above mentioned biomarkers.

Association of the T45G and G276T polymorphisms in the adiponectin gene with PCOS: A meta-analysis

Adiponectin is the most abundant adipocytokine in human body and may play a role in the pathogenesis of polycystic ovary syndrome (PCOS). To clarify the conflicting data in the literature concerning the association between PCOS and two polymorphisms of the adiponectin gene, T45G and G276T, a meta-analysis was performed in this study. Literature search was conducted through PubMed, EMBASE and other relevant studies. Pooled odds ratios (OR) were estimated using fixed-effects (FE) models in codominant, recessive and dominant models. Sensitive analysis was performed by excluding invalid studies. Eight articles investigated the T45G polymorphism in PCOS, and five publications are associated with the G276T polymorphism in PCOS. Significant associations of adiponectin T45G polymorphism with PCOS were found in codominant (FEM: OR = 1.36, 95% CI: 1.12-1.65), recessive (FEM: OR = 2.02, 95% CI: 1.17-3.47) or dominant models (FEM: OR = 1.33, 95% CI: 1.06-1.67). For adiponectin G276T polymorphism, the OR and 95% CI are 0.81(0.68, 0.98), 0.74(0.51, 1.09) and 0.78 (0.61, 0.99) in codominant, dominant and recessive models, respectively. This study provides positive evidence for a causal relationship between the adiponectin gene and PCOS which needs to be further confirmed by further studies.

Adipokines, insulin resistance and hyperandrogenemia in obese patients with polycystic ovary syndrome: cross-sectional correlations and the effects of weight loss

OBJECTIVE

To assess the effects of weight loss on serum adipokine levels in polycystic ovary syndrome (PCOS).

METHODS

We determined serum leptin, adiponectin, resistin, and visfatin levels in 60 overweight/obese women with PCOS and 48 BMI-matched female volunteers. Measurements were repeated after 24 weeks of treatment with orlistat 120 mg 3 times per day along with an energy-restricted diet.

RESULTS

At baseline, serum visfatin concentration was higher in patients with PCOS than in controls (p = 0.036); serum levels of leptin, adiponectin, and resistin did not differ between the two groups. After 24 weeks, a significant reduction in BMI and waist circumference was observed in both patients with PCOS and controls (p < 0.001 vs. baseline in both groups). Also serum leptin levels decreased in both patients with PCOS and controls (p < 0.001 vs. baseline in both groups). The reduction in serum leptin levels did not differ between groups. Serum adiponectin, resistin, and visfatin levels did not change in either group.

CONCLUSIONS

Leptin, adiponectin, and resistin do not appear to play major pathogenetic roles in overweight/obese patients with PCOS. In contrast, visfatin emerges as a potentially important mediator of the endocrine abnormalities of these patients. However, serum visfatin levels are not substantially affected by weight loss.