Decrease in adiponectin levels in women with polycystic ovary syndrome after an oral glucose tolerance test

Exploring the physiological factors relating to energy balance in women with polycystic ovary syndrome: a scoping review

Polycystic ovary syndrome (PCOS) occurs in 8%-13% of reproductive-aged women and is associated with reproductive, metabolic, and psychological dysfunction. Overweight and obesity are prevalent and exacerbate the features of PCOS. The aim of this review is to evaluate the extent of evidence examining the physiological factors affecting energy homeostasis, which may impact weight gain, weight loss, and weight maintenance in PCOS, and identify research gaps and recommendations for future research. Literature searches using MEDLINE, EMBASE, PsycInfo, AMED, CINAHL, and Cochrane Central Register of Controlled Trials were conducted up to June 22, 2022. Abstracts, non-English-language articles, and reviews were excluded. A total of n = 78 (n = 55 energy intake and n = 23 energy expenditure) primary research papers were included. Papers with multiple outcomes of interest were counted as separate studies. Energy-intake studies (n = 89) focussed on assessing food, nutrient, or supplements stimuli and were grouped into the outcomes of gastrointestinal appetite hormones (n = 43), adipokines (n = 34), subjective appetite (n = 9), functional brain imaging (n = 3), and neuropeptides (n = 0). Energy-expenditure studies (n = 29) were grouped into total energy expenditure (n = 1), resting energy expenditure (n = 15), meal-induced thermogenesis (n = 3), nutrient oxidation (n = 5), and metabolic flexibility (n = 5). Across both energy-intake and -expenditure papers, 60% of the studies compared outcome responses in women with PCOS with a control group. Results were inconsistent, with 57% reporting no differences and 43% reporting altered responses in PCOS compared with controls, including blunted appetite hormone responses, metabolic inflexibility, and reduced energy expenditure. The authors identified that there is inconsistent, yet preliminary, evidence of possible altered physiological factors, which may impact energy balance and weight management. Further work is needed to act on the identified clinical and research gaps to support women with PCOS and health professionals in informing and achieving realistic weight-management goals for women with PCOS.

SYSTEMATIC REVIEW REGISTRATION

The protocol was prospectively registered on the Open Science Framework on February 16, 2021 (https://osf.io/9jnsm).

Postprandial responses of circulating energy homeostasis mediators to single macronutrient challenges: influence of obesity and sex hormones

We analysed the influence of obesity, sex and sex steroids on the postprandial responses of circulating energy homeostasis mediators and their receptors to different macronutrient challenges. Seventeen women with polycystic ovary syndrome (PCOS, 8 with obesity), 17 non-hyperandrogenic control women (8 with obesity) and 19 control men (9 with obesity) were submitted, on alternate days, to isocaloric (300 kcal) oral glucose, lipid and protein loads. We evaluated serum ghrelin, leptin, soluble leptin receptor and adiponectin levels and the leukocyte gene expression of ghrelin (GHRL) and its receptor (GHSR), leptin receptor (LEPR) and adiponectin receptor 1 (ADIPOR1) during the macronutrient challenges. The postprandial responses of circulating energy homeostasis mediators were entirely different than those of their related genes. After macronutrient loads the postprandial response of serum energy homeostasis mediators showed a generalized physiological decrease that was blunted in subjects with obesity but was not influenced by sex, sex hormones or PCOS. However, gene expression of GHRL, LEPR and ADIPOR1 showed a marked increase following the ingestion of glucose compared with lipids and proteins, regardless of obesity and sex steroids. The physiological decrease after macronutrient loads, that was deregulated in obesity, did not reflect the acute leukocyte gene expression mainly after glucose, and may suggest a possible role for ghrelin, leptin and adiponectin in the postprandial inflammatory process.

Efficacy of omega-3 in the treatment of polycystic ovary syndrome

The purpose of this study was to evaluate the efficacy and safety of omega-3 in the treatment of polycystic ovary syndrome and to compare the clinical, hormonal, TNF-α and resistin levels in the patients treated with omega-3. A total of 45 non-obese PCOS women were studied. Women were treated with daily oral 1,500 mg of omega-3 for 6 months. Body mass index (BMI), hirsutism score, fasting glucose and insulin levels were noted for each case. Hirsutism was assessed at 6-month intervals using the Ferriman-Gallwey (F-G) scoring system. Hormonal, TNF-α and resistin levels at 6 months of therapy were compared with baseline values. BMI, F-G scoring, insulin and HOMA levels decreased significantly during treatment, but glucose levels did not change. In the hormonal profile, serum LH and testosterone levels decreased and sex hormone-binding globulin levels increased significantly after the 6 months of therapy. On the other hand, TNF-α levels showed a significant increase, whereas resistin levels showed no change. Omega-3 may be also effective in improving hirsutism and insulin resistance in patients with PCOS.

Adiponectin and its receptors modulate granulosa cell and cumulus cell functions, fertility, and early embryo development in the mouse and human

OBJECTIVE

To study the expression and function of adiponectin and its receptors in mouse and human follicle cells and in early embryo development.

DESIGN

Whole ovaries, granulosa cells, and cumulus-oocyte complexes isolated from immature mice before and during hormone-induced ovulation were used to analyze the expression of adiponectin, its receptors, and ovulation-related genes; human cumulus cells and granulosa cells were isolated from patients undergoing in vitro fertilization (IVF) procedures.

SETTING

Multicenter.

PATIENT(S)

Women in IVF programs in Japan and the United States.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Expression of adiponectin receptors and fertility.

RESULT(S)

Adiponectin expression is absent/low in mouse and human granulosa cells and cumulus cells. Adiponectin receptors are hormonally regulated in mouse granulosa and cumulus cells in vivo and in culture. Adiponectin differentially alters the expression of Adipor1/Adipor2 as well as genes related to steroidogenesis, ovulation, and apoptosis in cumulus cells versus granulosa cells. Adiponectin enhances oocyte maturation and early embryo development in mouse and human IVF procedures.

CONCLUSION(S)

Adiponectin can modulate not only follicle growth but also embryo development in mice and humans.

Oxidized low-density lipoprotein and adiponectin levels in pregnancy

INTRODUCTION

The aim of the present study was to investigate whether normal pregnancy represents a complex state of oxidative stress, inflammation and insulin resistance.

SUBJECTS AND METHODS

One hundred and six pregnant women, between 24th and 28th week of pregnancy (age 27.9 ± 0.4 years) (study group) and one hundred and six age-matched, healthy, non-pregnant women (control group) participated in the study. Serum levels of glucose, insulin, adiponectin, oxidized LDL (oxLDL) and lipid parameters, i.e. total cholesterol (TC), triglycerides (TG), HDL and LDL, were determined. Body mass index (BMI) and QUantitative Insulin sensitivity ChecK Index (QUICKI) were also calculated.

RESULTS

Pregnant women presented higher BMI values, insulin and oxLDL serum levels and lower glucose serum levels than controls. Serum levels of lipids (TC, TG, LDL and HDL) were higher in pregnant women. There was a significant positive correlation of oxLDL to adiponectin (p < 0.01) in the study group, but not in the controls, and no other significant correlation with any of the other parameters, in either of groups.

CONCLUSIONS

Pregnancy is a state of insulin resistance, oxidative stress and pro-atherogenic hyperlipidemia. Adiponectin may, though, have cardioprotective role in pregnant women.

Developmental programming: effect of prenatal steroid excess on intraovarian components of insulin signaling pathway and related proteins in sheep

Prenatal testosterone (T) excess increases ovarian follicular recruitment, follicular persistence, insulin resistance, and compensatory hyperinsulinemia. Considering the importance of insulin in ovarian physiology, in this study, using prenatal T- and dihydrotestosterone (DHT, a nonaromatizable androgen)-treated female sheep, we tested the hypothesis that prenatal androgen excess alters the intraovarian insulin signaling cascade and metabolic mediators that have an impact on insulin signaling. Changes in ovarian insulin receptor (INSRB), insulin receptor substrate 1 (IRS1), mammalian target of rapamycin (MTOR), phosphatidylinositol 3-kinase (PIK3), peroxisome proliferator-activated receptor-gamma (PPARG), and adiponectin proteins were determined at fetal (Days 90 and 140), postpubertal (10 mo), and adult (21 mo) ages by immunohistochemistry. Results indicated that these proteins were expressed in granulosa, theca, and stromal compartments, with INSRB, IRS1, PPARG, and adiponectin increasing in parallel with advanced follicular differentiation. Importantly, prenatal T excess induced age-specific changes in PPARG and adiponectin expression, with increased PPARG expression evident during fetal life and decreased antral follicular adiponectin expression during adult life. Comparison of developmental changes in prenatal T and DHT-treated females found that the effects on PPARG were programmed by androgenic actions of T, whereas the effects on adiponectin were likely by its estrogenic action. These results suggest a role for PPARG in the programming of ovarian disruptions by prenatal T excess, including a decrease in antral follicular adiponectin expression and a contributory role for adiponectin in follicular persistence and ovulatory failure.

Adiponectin and resistin concentrations after glucose load in adolescents with polycystic ovary syndrome

Our aims were to evaluate the serum adiponectin and resistin levels at fasting and after glucose load and their interaction with risk of cardiovascular disease (CVD) in adolescents with polycystic ovary syndrome (PCOS). Twenty-two adolescents with PCOS and 16 healthy controls were included in the study. Oral glucose tolerance test (OGTT) was performed in all adolescents. Fasting lipids was measured. Insulin, glucose, adiponectin, and resistin levels were measured at 0 and 120 min of OGTT. Homeostasis model assessment of insulin resistance (HOMA-IR), quantitative insulin-sensitivity check index (QUICKI), fasting glucose-to-insulin ratio (FGIR), and the whole -body insulin sensitivity index (ISI) were calculated. Fasting adiponectin was correlated with ISI (r = 0.729, p < 0.0001), FGIR (r = 0.696, p < 0.0001), QUICKI (r = 0.592, p = 0.004) and HDL-C (r = 0.516, p = 0.028), systolic blood pressure (r = -0.732, p < 0.0001), body mass index (r = -0.738, p < 0.0001), waist circumference (r = -0.706, p < 0.0001), and HOMA-IR (r = -0.595, p = 0.003). No correlation was found between resistin and insulin resistance indexes. Obese adolescents with PCOS have increased CVD risk such as dyslipidemia, hypertension, and insulin resistance than normo-weight PCOS. Hypoadiponectinaemia could be increase risks levels in obese girls with PCOS.

Plasma visfatin levels in normal weight women with polycystic ovary syndrome

BACKGROUND

The present study was designed to measure plasma visfatin levels in normal weight women with polycystic ovary syndrome (PCOS) and to assess possible correlations between visfatin and the hormonal or metabolic parameters of the syndrome.

METHODS

Twenty-five normal weight [body mass index (BMI)<25 kg/m(2)] women with PCOS, 24 obese and overweight (BMI>25 kg/m(2)) controls (ovulating women without clinical or biochemical hyperandrogenism), and 24 normal weight controls were studied. Blood samples were collected between the 3rd and the 7th days of a menstrual cycle in the control groups and during a spontaneous bleeding episode in the PCOS groups at 9:00 A.M., after an overnight fast. Circulating levels of LH, FSH, prolactin (PRL), testosterone (T), Delta(4)-androstenedione (Delta(4)-Alpha), dehydroepiandrosterone sulfate (DHEA-S), 17alpha-OH-progesterone (17OH-P), sex hormone-binding globulin (SHBG), insulin, glucose, and visfatin were measured.

RESULTS

Plasma visfatin levels and the visfatin-to-insulin ratio were significantly lower in normal weight controls than in both normal weight women with PCOS and overweight or obese controls. The visfatin-to-insulin ratio was significantly higher in normal weight women with PCOS than in overweight or obese controls. Plasma visfatin levels were found to be positively correlated with LH and Delta(4)A levels, as well as with free androgen index (FAI) values, and negatively correlated with SHBG. LH and SHBG levels were found to be the only independent significant determinants of circulating visfatin. In the control groups, plasma visfatin levels were significantly correlated with BMI, waist (W) measurement, and waist-to-hip ratio (WHR).

CONCLUSIONS

Visfatin levels are positively associated with obesity in healthy women of reproductive age. Moreover, the present study indicates, for the first time, a possible involvement of increased visfatin levels in PCOS-associated metabolic and hormonal disturbances.

Role of adiponectin in regulating ovarian theca and granulosa cell function

Adiponectin is an adipokine that has been implicated in insulin resistance, a condition associated with polycystic ovarian syndrome in humans, but whether adiponectin can directly affect ovarian theca or granulosa cell function is unknown. Therefore, to determine the effects of adiponectin on proliferation, steroidogenesis and gene expression of large-follicle theca and granulosa cells, experiments were conducted using bovine ovarian cell cultures. RT-PCR was used to elucidate the effects of adiponectin on gene expression of CYP11A1 and LH receptor (LHR) in large-follicle theca and granulosa cells, as well as expression of CYP17A1 in theca cells and CYP19A1 in granulosa cells. Adiponectin decreased (P<0.05) insulin-induced progesterone and androstenedione production as well as attenuated IGF-I-induced LHR, CYP11A1, and CYP17A1 gene expression in theca cells. In contrast, adiponectin decreased (P<0.05) LHR mRNA abundance in granulosa cells but did not affect steroidogenic enzyme gene expression in granulosa cells. Adiponectin had no effect (P>0.10) on proliferation of large-follicle theca cells. RT-PCR also revealed that abundance of mRNA for the adiponectin receptor (ADIPOR2) was greater (P<0.05) in large-follicle than in small-follicle theca cells and did not significantly differ between small- and large-follicle granulosa cells. In cultured theca cells, LH increased (P<0.05) and IGF-I decreased (P<0.05) ADIPOR2 mRNA abundance. These results indicate that the inhibitory effects of adiponectin on steroidogenesis are primarily localized to theca cells and that the response of theca cells to adiponectin (i.e., ADIPOR2) may be regulated by LH and IGF-I.

Adipokines in NASH: postprandial lipid metabolism as a link between adiponectin and liver disease

Circulating levels of four adipokines (adiponectin, TNF-alpha, leptin, and resistin) and the postprandial lipid and adiponectin responses to an oral fat load were assessed in 25 non-obese, non-diabetic patients with biopsy-proven nonalcoholic steatohepatitis (NASH) and correlated with metabolic indices and liver histology. Circulating adiponectin was lower in NASH compared with controls (5,476 +/- 344 vs. 11,548 +/- 836 ng/mL; P = .00001) and on multiple regression analysis correlated negatively with liver steatosis, necroinflammation (OR = 5.0; P = .009), and fibrosis (OR = 8.0; P = .003). The magnitude of postprandial lipemia was significantly higher in NASH than in controls and was related to fasting adiponectin (beta = -0.78; P = .00003). Controls showed a significant increase in serum adiponectin in response to the fat load, whereas patients with NASH showed a slight decrease. Postprandial free fatty acids response correlated inversely with adiponectin response in both groups and independently predicted the severity of liver steatosis in NASH (beta = 0.51; P = .031). In conclusion, hypoadiponectinemia is present before overt diabetes and obesity appear and correlates with the severity of liver histology in NASH. Impaired postprandial lipid metabolism may be an additional mechanism linking hypoadiponectinemia and NASH and posing a higher cardiovascular risk to these subjects. The mechanism(s) underlying these differences are unknown, but the type of dietary fat seems to play a role. These findings may have important pathogenetic and therapeutic implications in both liver and metabolic disease.