Insulin resistance variability in women with anovulatory and ovulatory polycystic ovary syndrome, and normal controls

The role of the thyroid in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrine and metabolic disease in women of childbearing age and can cause metabolic disorder, infertility, and increased anxiety and depression; as a result, it can seriously affect the physical and mental health of fertile women. PCOS is a highly clinically heterogeneous disease with unclear etiology and pathogenesis, which increases the difficulty of treatment. The thyroid gland has complex regulatory effects on metabolism, reproduction, and emotion, and produces hormones that act on almost all cells of the human body. The clinical manifestations of PCOS are similar to some thyroid diseases. Furthermore, some thyroid diseases, such as subclinical hypothyroidism (SCH), not only increase the incidence rate of PCOS, but also exacerbate its associated metabolic abnormalities and reproductive disorders. Interestingly, PCOS also increases the incidence of some thyroid diseases. However, the role of the thyroid in PCOS remains unclear. This review is intended to thoroughly explore the critical role of the thyroid in PCOS by summarizing the comorbidity of PCOS and thyroid diseases and their combined role in metabolic disorders, related metabolic diseases, and reproductive disorders; and by analyzing the potential mechanism through which the thyroid influences the development and progression of PCOS and its symptoms. We hope this review will provide a valuable reference for the role of the thyroid in PCOS.

The Role of Glp-1 Receptor Agonists in Insulin Resistance with Concomitant Obesity Treatment in Polycystic Ovary Syndrome

Insulin resistance is documented in clamp studies in 75% of women with polycystic ovary syndrome (PCOS). Although it is not included in the diagnostic criteria of PCOS, there is a crucial role of this metabolic impairment, which along with hormonal abnormalities, increase each other in a vicious circle of PCOS pathogenesis. Insulin resistance in this group of patients results from defects at the molecular level, including impaired insulin receptor-related signaling pathways enhanced by obesity and its features: Excess visceral fat, chronic inflammation, and reactive oxygen species. While lifestyle intervention has a first-line role in the prevention and management of excess weight in PCOS, the role of anti-obesity pharmacological agents in achieving and maintaining weight loss is being increasingly recognized. Glucagon-like peptide-1 receptor agonists (GLP1-RAs) not only act by reducing body weight but also can affect the mechanisms involved in insulin resistance, like an increasing expression of glucose transporters in insulin-dependent tissues, decreasing inflammation, reducing oxidative stress, and modulating lipid metabolism. They also tend to improve fertility either by increasing LH surge in hypothalamus-pituitary inhibition due to estrogen excess connected with obesity or decreasing too high LH levels accompanying hyperinsulinemia. GLP1-RAs seem promising for effective treatment of obese PCOS patients, acting on one of the primary causes of PCOS at the molecular level.

Using metabolic markers to identify insulin resistance in premenopausal women with and without polycystic ovary syndrome

BACKGROUND

Insulin resistance (IR) is associated with increased risk for type 2 diabetes mellitus and cardiovascular disease. Quantifying IR is invasive and time-consuming, and thus not routinely used in clinical practice. Simple metabolic markers to predict IR exist, but have not been validated in premenopausal women or women with polycystic ovary syndrome (PCOS).

OBJECTIVE

To evaluate the ability of metabolic markers to identify premenopausal women with/without PCOS who are insulin resistant.

DESIGN/SETTING

Cross-sectional analysis.

PARTICIPANTS

One hundred and seventy-one non-diabetic premenopausal overweight/obese women without PCOS and 71 women with PCOS.

METHODS

IR was quantified by the steady-state plasma glucose during the modified insulin-suppression test. Metabolic markers (BMI, lipid/lipoprotein concentrations, and fasting glucose) were evaluated for their discriminative ability to identify IR, using area under the receiver-operating-characteristic curve (AUROC) analysis. Optimal cut-points were evaluated for predictive power.

RESULTS

In the non-PCOS group, the triglyceride/HDL cholesterol ratio (TG/HDL-C) was the best marker (AUROC 0.73). Optimal diagnostic cut-point was 1.9. In the PCOS group, the TG/HDL-C ratio, cholesterol/HDL-C ratio (TC/HDL-C), and HDL-C performed well (AUROC > 0.80), with optimal cut-points for TG/HDL-C 1.3, TC/HDL-C 3.4, and HDL-C 52 mg/dL: TG/HDL-C was more sensitive, but HDL-C had a higher PPV for IR.

CONCLUSION

TG/HDL-C can identify IR in premenopausal women with and/without PCOS; diagnostic cut-points differ from those of men and postmenopausal women. HDL-C is an alternative predictor in women with PCOS. These simple metabolic markers, which are standardized between labs, inexpensive, and routinely measured, can be used to tailor lifestyle and medical interventions to improve health outcomes in insulin-resistant premenopausal women.

Variability of HOMA and QUICKI insulin sensitivity indices

Assessment of insulin sensitivity based on a single measurement of insulin and glucose, is both easy to understand and simple to perform. The tests most often used are HOMA and QUICKI. The aim of this study was to assess the biological variability of estimates of insulin sensitivity using HOMA and QUICKI indices. After a 12-h fast, blood was sampled for insulin and glucose determination. Sampling lasted for 90 min with an intersample interval of 2 min. A total of 56 subjects were included in the study, and in nine subjects sampling was done before and after weight reduction, so total number of analyzed series was 65. To compute the reference value of the insulin sensitivity index, averages of all 46 insulin and glucose samples were used. We also computed point estimates (single value estimates) of the insulin sensitivity index based on the different number of insulin/glucose samples (1-45 consecutive samples). To compute the variability of point estimates a bootstrapping procedure was used using 1000 resamples for each series and for each number of samples used to average insulin and glucose. Using a single insulin/glucose sample HOMA variability was 26.18 ± 4.31%, and QUICKI variability was 3.30 ± 0.54%. For 10 samples variability was 11.99 ± 2.22% and 1.62 ± 0.31% respectively. Biological variability of insulin sensitivity indices is significant, and it can be reduced by increasing the number of samples. Oscillations of insulin concentration in plasma are the major cause of variability of insulin sensitivity indices.

Substituting poly- and mono-unsaturated fat for dietary carbohydrate reduces hyperinsulinemia in women with polycystic ovary syndrome

OBJECTIVE

Hyperinsulinemia is a prevalent feature of polycystic ovary syndrome (PCOS), contributing to metabolic and reproductive manifestations of the syndrome. Weight loss reduces hyperinsulinemia but weight regain is the norm, thus preventing long-term benefits. In the absence of weight loss, replacement of dietary carbohydrate (CHO) with mono/polyunsaturated fat reduces ambient insulin concentrations in non-PCOS subjects. The current study evaluated whether this dietary intervention could ameliorate hyperinsulinemia in women with PCOS.

DESIGN/SETTING/PATIENTS

Obese women with PCOS (BMI 39 ± 7 kg/m²) and insulin resistance completed a crossover study (Stanford University Clinical Research Center) comparing two isocaloric diets, prepared by research dietitians, containing 60% CHO/25% fat versus 40% CHO/45% fat (both 15% protein and ≤7% saturated fat). After 3 weeks on each diet, daylong glucose, insulin, and fasting lipid/lipoproteins were measured.

RESULTS

Daylong glucose did not differ according to diet. Daylong insulin concentrations were substantially (30%) and significantly lower on the low CHO/higher fat diet. Beneficial changes in lipid profile were also observed.

CONCLUSIONS

Replacement of dietary CHO with mono/polyunsaturated fat yields clinically important reductions in daylong insulin concentrations, without adversely affecting lipid profile in obese, insulin-resistant women with PCOS. This simple and safe dietary intervention may constitute an important treatment for PCOS. ClinicalTrials.gov Identifier: NCT00186459.

Diabetes mellitus and gynecologic cancer: molecular mechanisms, epidemiological, clinical and prognostic perspectives

INTRODUCTION

Diabetes mellitus, the prevalence of which has increased dramatically worldwide, may put patients at a higher risk of cancer. The aim of our study is the clarification of the possible mechanisms linking diabetes mellitus and gynecological cancer and their epidemiological relationship.

MATERIALS AND METHODS

This is a narrative review of the current literature, following a search on MEDLINE and the Cochrane Library, from their inception until January 2012. Articles investigating gynecologic cancer (endometrial, ovarian, and breast) incidence in diabetic patients were extracted.

RESULTS

The strong evidence for a positive association between diabetes mellitus and the risk for cancer indicates that energy intake in excess to energy expenditure, or the sequelae thereof, is involved in gynecological carcinogenesis. This risk may be further heightened by glucose which can directly promote the production of tumor cells by functioning as a source of energy. Insulin resistance accompanied by secondary hyperinsulinemia is hypothezised to have a mitogenic effect. Steroid hormones are in addition potent regulators of the balance between cellular differentiation, proliferation, and apoptosis. Inflammatory pathways may also be implicated, as a correlation seems to exist between diabetes mellitus and breast or endometrial carcinoma pathogenesis, although an analogous correlation with ovarian carcinoma is still under investigation. Antidiabetic agents have been correlated with elevated cancer risk, while metformin seems to lower the risk.

CONCLUSION

Diabetes mellitus is associated with an elevation in gynecologic cancer risk. Moreover, there are many studies exploring the prognosis of patients with diabetes and gynecological cancer, the outcome and the overall survival in well-regulated patients.

Overweight, obesity and central obesity in women with polycystic ovary syndrome: a systematic review and meta-analysis

BACKGROUND Polycystic ovary syndrome (PCOS) is closely associated with obesity but the prevalence of obesity varies between published studies. The objective of this research was to describe the prevalence of overweight, obesity and central obesity in women with and without PCOS and to assess the confounding effect of ethnicity, geographic regions and the diagnostic criteria of PCOS on the prevalence. METHODS MEDLINE, EMBASE, CINAHL, Cochrane Central Register of Controlled Trials (CENTRAL) and PSYCINFO were searched for studies reporting the prevalence of overweight, obesity or central obesity in women with and without PCOS. Data were presented as prevalence (%) and risk ratio (RR) [95% confidence interval (CI)]. Random-effect models were used to calculate pooled RR. RESULTS This systematic review included 106 studies while the meta-analysis included 35 studies (15129 women). Women with PCOS had increased prevalence of overweight [RR (95% CI): 1.95 (1.52, 2.50)], obesity [2.77 (1.88, 4.10)] and central obesity [1.73 (1.31, 2.30)] compared with women without PCOS. The Caucasian women with PCOS had a greater increase in obesity prevalence than the Asian women with PCOS compared with women without PCOS [10.79 (5.36, 21.70) versus 2.31 (1.33, 4.00), P < 0.001 between subgroups). CONCLUSIONS Women with PCOS had a greater risk of overweight, obesity and central obesity. Although our findings support a positive association between obesity and PCOS, our conclusions are limited by the significant heterogeneity between studies and further studies are now required to determine the source of this heterogeneity. Clinical management of PCOS should include the prevention and management of overweight and obesity.

Glucose-induced increase in circulating progenitor cells is blunted in polycystic amenorrhoeic subjects

BACKGROUND

Glucose-induced kinetics of bone marrow-derived stem cells in healthy females is presently unknown. The objectives of this study were to determine whether circulating levels of CD133(+), CD34(+) and CD133(+)CD34(+) cells increase in response to glucose load in healthy females and whether the kinetics is altered in amenorrhoeic women. The other objective of the work was to compare the endothelial differentiation potential of peripheral blood-derived endothelial progenitor cells (EPCs) from healthy versus amenorrhoeic women.

METHODS

In this case-control study, 44 amenorrhoeic subjects and 36 age-matched females with no menstrual disturbance were recruited at Apollo Hospitals, a Tertiary health care center in Chennai, India. Circulating bone marrow-derived stem cells were measured by two color direct flow cytometry. Cultured progenitor cells were characterized at Day 7 and 14 for expression of endothelial markers and production of nitric oxide (NO) via immunofluoroscence.

RESULTS

The amenorrhoeic subjects were insulin resistant with homeostatic model of assessment of insulin resistance values of 3.33 ± 0.3 versus 1.75 ± 0.148 observed for controls (P< 0.0001). Among the amenorrhoeic subjects, 38 subjects had polycystic ovaries with no signs of hyperandrogenism. Fasting levels of CD133(+), CD34(+) and CD133(+)CD34(+) cells were reduced in amenorrhoeic subjects (P< 0.001). There was a 1.5 to 2-fold increase in the circulating levels of these cells in response to 75 g oral glucose challenge at 1 and 2 h post-load conditions in controls, which was significantly blunted for CD133(+) (P< 0.001) and CD133(+)CD34(+) (P< 0.001) cells in amenorrhoeic subjects. A positive correlation was observed between estrogen and fasting CD133(+) (r= 0.205, P= 0.070), CD34(+) (r= 0.249, P= 0.027) and CD133(+)CD34(+) (r= 0.217, P= 0.055) cell counts. Additionally, fasting counts for CD34(+) and CD133(+)CD34(+) cells positively correlated with FSH and inversely correlated with LH and C-peptide in the polycystic group. Cultured cells from polycystic subjects exhibited reduced adherence to fibronectin and expressed lower levels of endothelial nitric-oxide synthase and NO.

CONCLUSIONS

Oral glucose-induced increase in circulating numbers of CD133(+) and CD133(+)CD34(+) cells and endothelial differentiation potential of peripheral blood-derived EPCs is attenuated in insulin resistant amenorrhoeic subjects.