Low levels of low molecular weight insulin-like growth factor-binding protein in patients with polycystic ovarian disease

Decreased Endometrial Thickness Is Associated With Higher Risk of Neonatal Complications in Women With Polycystic Ovary Syndrome

PURPOSE

To evaluate the association of endometrial thickness (EMT) with obstetric and neonatal outcomes in women with polycystic ovary syndrome (PCOS).

METHODS

A total of 1755 subfertile PCOS women with singleton livebirths after frozen-thawed embryo transfer were included between January 2009 and September 2019. Main obstetric outcomes were hypertensive disorders in pregnancy and abnormal placentation. Main neonatal outcomes were preterm birth (PTB), low birthweight (LBW) and small-for-gestational age (SGA). Crude and adjusted odds ratios (ORs) with 95% confidence intervals (CIs) were estimated by univariate and multivariate logistic regression analyses.

RESULTS

Each millimeter decrease in EMT was related to a 9% (adjusted OR 1.09, 95% CI 1.00-1.19; P = 0.053), 14% (adjusted OR 1.14, 95% CI 1.02-1.28; P = 0.002) and 22% (adjusted OR 1.22, 95% CI 1.07-1.38; P = 0.003) higher risk of PTB, LBW and SGA, respectively. Compared to women with EMT >13 mm, women with EMT ≤8 mm also had significantly higher risk of PTB (adjusted OR 3.79, 95% CI 1.53-9.39; P = 0.004), LBW (adjusted OR 4.33, 95% CI 1.39-13.50; P = 0.012) and SGA (adjusted OR 6.38, 95% CI 1.78-22.83; P = 0.004). These associations remained consistent in further subgroup analysis by endometrial preparation regimen and in sensitivity analyses among nulligravida women or women without adverse obstetric outcomes. No significant differences were found in the incidence of several pregnancy complications across EMT categories.

CONCLUSION

Decreased EMT was independently associated with increased risk of PTB, LBW and SGA in women with PCOS.

Polycystic Ovary Syndrome and the Forgotten Uterus

Polycystic ovary syndrome (PCOS) is a common disorder that affects various facets of fertility. Although the ovarian and metabolic aspects of the disease is well studied, its role in uterine dysfunction is not well understood. Our objective was to review the features of endometrial and uterine aberrations in women with PCOS. A systematic literature search was performed in PubMed, Medline, and the Cochrane Library databases for papers published in English up to March 2020. The following key words were used for the search: polycystic ovary syndrome, poly cystic ovarian disease, polycystic ovaries, PCOS, PCOD, PCO, PCOM, oligoovulation, anovulation, oligomenorrhea, amenorrhea, hyperandrogenism and this was combined with terms; endometrium, infertility, uterus, progesterone resistance, endometrial hyperplasia, pregnancy outcomes, preterm delivery. In this review, we highlight various uterine pathologies that are associated with PCOS and explore its impact on fertility. We also discuss key uterine molecular pathways that are altered in PCOS that may be related to infertility, endometrial hyperplasia and cancer.

A comparison of IVF outcomes transferring a single ideal blastocyst in women with polycystic ovary syndrome and normal ovulatory controls

PURPOSE

To assess the effects PCOS on live birth rates when transferring a single fresh ideal blastocyst.

METHODS

A retrospective cohort study performed at the university-affiliated reproductive center. Women with PCOS and a control group of normal ovulatory women who underwent their first fresh embryo transfer with single ideal grade blastocyst were included in the study. Demographic, stimulation information and pregnancy outcomes were collected and analysed. The primary outcome was live birth rates, and secondary outcomes included pregnancy and clinical pregnancy rates.

RESULTS

71 Women with PCOS and 272 normal ovulatory controls underwent their first embryo transfer and met the inclusion and exclusion criteria. PCOS patient were younger (31.0 ± 3.7 vs. 33.1 ± 3.2, p = 0.0001), with higher AFC (40.0 ± 9.3 vs. 13.3 ± 4.6, p = 0.0001), required lower dose of gonadotropins to stimulate (1198 ± 786 vs. 1891 ± 1224, p = 0.0001), and had higher serum testosterone levels (2.3 ± 0.7 vs. 1.1 ± 0.3, p = 0.0001). No significant difference was found between the two groups regarding the number of previous pregnancies, the number of previous full-term pregnancies, the level of basal serum FSH, estradiol level at triggering and the BMI. When compared by Chi squared testing pregnancy rates, clinical pregnancy rates and live birth rates did not differ. However, when controlling (with multivariate stepwise logistic regression) for confounders, live birth rates were lower among the women with PCOS (p = 0.035, CI: 0.18-0.92).

CONCLUSION

After controlling for confounders, when transferring a fresh single ideal blastocyst, live birth rates were lower among the women with PCOS than normal ovulatory controls.

The effect of cinnamon on polycystic ovary syndrome in a mouse model

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most prevalent cause of anovulatory infertility and hyperandrogenism. Evidence favors insulin resistance and compensatory hyperinsulinemia as the predominant, perhaps primary, defects in PCOS. The use of insulin-sensitizing drugs has been shown to improve both the reproductive and the metabolic aspects of PCOS. Cinnamon has been found to have insulin sensitizing effect and improve menstrual cyclicity in women with PCOS. The aim of this study was to determine the effect and mechanism of cinnamon on PCOS using a dehydroepiandrosterone (DHEA) induced PCOS mouse model.

METHODS

Prepubertal C57BL/6 mice (age 25 days) were raised to developed into control group, DHEA group and DHEA plus cinnamon group for 20 days. The stages of the estrous cycle were determined based on vaginal cytology; metabolic characteristics were examined by intraperitoneal glucose tolerance test and insulin tolerance test, the serum levels of hormones (testosterone, insulin, LH, FSH, IGF-1, IGFBP-1) were checked using enzyme-linked immunosorbent assay (ELISA) method, the ovarian morphology was observed by stained with hematoxylin and eosin. IGF-1 and IGFBP-1 expression in ovary were detected by immunohistochemical stain.

RESULTS

Cinnamon restores the cyclicity and ovary morphology in PCOS mice model induced by DHEA. There are significant differences of serum level of total testosterone (0.033 ± 0.009 ng/ml), among control group, DHEA and cinnamon group (0.052 ± 0.011 ng/ml), and DHEA group (0.079 ± 0.015 ng/ml); There was an increasing tendency of serum FSH level from DHEA group (5.02 ± 0.31 ng/ml), DHEA and cinnamon group (5.81 ± 0.51 ng/ml), to control group (7.13 ± 0.74 ng/ml); and there was a decreasing trend of serum LH level from DHEA group (3.75 ± 0.57 ng/ml), DHEA and cinnamon group (1.35 ± 0.61 ng/ml), or control group (0.69 ± 0.34 ng/ml); serum insulin level is significantly higher in DHEA treated mice (1.61 ± 0.31 ng/ml) than control group (0.93 ± 0.19 ng/ml), or DHEA and cinnamon effect (1.27 ± 0.23 ng/ml) (p < 0.05). The DHEA group also has a higher serum IGF-1 level (0.35 ± 0.06 ng/ml) than control group (0.17 ± 0.04 ng/ml) or DHEA and cinnamon group (0.21 ± 0.05 ng/ml) (p < 0.05). While DHEA group has a lower IGFBP-1 level (5.5 ± 1.6 ng/ml) than control group (15.8 ± 2.1 ng/ml) or DHEA and cinnamon group (10.3 ± 2.5 ng/ml) (p < 0.05). Cinnamon also attenuates DHEA induced a higher IGF-1 and lower IGFBP-1 expression in ovary by immunohistochemistry.

CONCLUSIONS

These preliminary data suggest that cinnamon supplementation improves insulin resistance and may be a potential therapeutic agent for the treatment of PCOS.

Endometrial injury for patients with endometriosis and polycystic ovary syndrome undergoing medically assisted reproduction: current data and a protocol

We propose a study protocol capable of improving clinical outcomes following medically assisted reproduction (MAR) in infertile women with endometriosis and polycystic ovary syndrome (PCOS). The proposed research derives from the published evidence on the positive impact from endometrial injury (EI) and the beneficial nature of the intervention towards improved implantation rates. We primarily refer to the cluster of events and hypotheses, such as the mechanical cascade, the inflammatory response per se, the events accompanying wound healing, the immune cell recruitment and protein involvement, alterations in gene expression and the neo-angiogenesis theories, which have been previously investigated for this purpose. We are also exploring the possible problems in MAR cycles with negative outcomes in PCOS and endometriosis patients and we are proposing potential mechanisms on how this intervention might work. Our hypothesis states that the EI before the initiation of the MAR cycle can affect clinical pregnancy rates in patients with the aforementioned pathologies.

Endometrial flushing αVβ3 integrin, glycodelin and PGF2α levels for evaluating endometrial receptivity in women with polycystic ovary syndrome, myoma uteri and endometrioma

The aim of this cross-sectional study is to compare endometrial flushing fluid levels of α_Vβ₃ integrin, glycodelin and PGF2α during the midluteal phase of the menstrual cycle of women with polycystic ovary syndrome (PCOS, n = 20), myoma uteri (n = 20) and endometrioma (n = 19) with the healthy controls (n = 20). After collecting samples at the midluteal phase of ovulatory volunteers and storing them at -80 °C, α_Vβ₃ integrin, glycodelin and PGF2α levels were analyzed using ELISA. The mean ages of the groups were 28.90 ± 5.45, 37.25 ± 2.73, 32.84 ± 6.62 and 32.15 ± 5.18 in PCOS, myoma uteri, endometrioma and control groups, respectively. The α_Vβ₃ integrin level (ng/ml) was statistically significantly higher in endometrioma group (9.70 ± 1.72, p < 0.05) as compared to myoma uteri and control groups. Similarly, glycodelin level (ng/ml) was significantly higher in endometrioma group (341.04 ± 93.32) than PCOS (p < 0.01), myoma uteri (p < 0.001) and healthy subjects (p < 0.001). Moreover, PGF2α level (350.04 ± 464.50 ng/ml) was significantly higher in PCOS group relative to myoma uteri (p < 0.001), endometrioma (p < 0.05) and control (p < 0.05) groups. In conclusion, α_Vβ₃ integrin level was significantly higher in endometrioma subjects than those with myoma uteri and control groups; glycodelin level was significantly higher in endometrioma group than other three groups, and lastly, PCOS patients had significantly higher PGF2α levels than those patients with myoma uteri, endometrioma and controls.

Modulation of the IGF system and proliferation in human endometrial stromal cells by metformin: a dose-dependent effect

PURPOSE

To assess the metformin effect on endometrial stromal cell decidualization, proliferation, gene and protein expression of IGFBPs, IGFs and their receptors.

METHODS

Human endometrial stromal cells (hESCs) were cultured from endometrial biopsies of 11 women undergoing surgery for benign reasons. hESCs were decidualized with and without metformin in increasing doses. Supernatant and cells were harvested after decidualization for 12-14 days, followed by real-time PCR of IGFBP 1-6, IGF I, IGF II and their receptors. Prolactin, and IGFBP-1, -3, and -6 were additionally analyzed in supernatant by ELISA. Proliferation of hESCs and decidualization of hESCs were assessed under the influence of metformin. Data were analyzed using the paired t test with p < 0.05 considered significant.

RESULTS

While lower concentrations of metformin (10(-4), 10(-5 )M) did not influence the decidualization and proliferation capacity of hESCs, higher concentrations (10(-3), 10(-2 )M metformin) significantly (p < 0.05) diminished decidualization, as well as stromal cell proliferation in a dose-dependent manner. Higher concentrations of metformin lead to a significant (p < 0.05) dose-dependent attenuation of the progesterone effect with regard to IGFBP-1, -3, -5, -6, as well as IGF I receptor, while it did not change the expression of IGFBP-2 and -4, IGF I and II and the IGF II receptor. This was confirmed on the protein level for IGFBP-1, -3, and -6.

CONCLUSION

We were able to demonstrate for the first time a dose-dependent local effect of metformin within hESCs. Metformin might therefore influence locally the endometrial proliferation and maturation, and could open up new treatment options for gynecological diseases by vaginal application of metformin.

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.

Metformin: direct inhibition of rat ovarian theca-interstitial cell proliferation

OBJECTIVE

To determine whether metformin has direct effects on ovarian theca-interstitial (T-I) cell proliferation through activation of adenosine monophosphate-activated protein kinase (AMPK).

DESIGN

In vitro experimental study.

SETTING

Academic medical center laboratory.

ANIMAL(S)

Immature Sprague-Dawley female rats.

INTERVENTION(S)

Ovarian T-I cells were isolated, purified, and cultured in the absence (control) or presence of insulin (1 μg/mL) with or without metformin or other activators/inhibitors of AMPK (AICAR, compound C).

MAIN OUTCOME MEASURE(S)

Proliferation assessed by determination of expression levels of proteins involved in cell cycle progression, cyclin D3, and cyclin-dependent kinase 4 (CDK4) with Western blot analysis, and determination of DNA synthesis with bromodeoxyuridine (BrdU) incorporation assay; activation of AMPK, Erk1/2, and S6K1 determined by Western blot analysis with the use of antibodies specific for the phosphorylated (activated) forms.

RESULT(S)

Metformin inhibited insulin-induced ovarian T-I cell proliferation and the up-regulation of the cell cycle regulatory proteins, cyclin D3 and CDK4. Metformin independently activated AMPK in a dose-dependent manner. Treatment with metformin inhibited insulin-induced activation of Erk1/2 and S6K1. This effect was reversed with the addition of compound C, a known AMPK inhibitor.

CONCLUSION(S)

Metformin directly inhibits proliferation of ovarian T-I cells via an AMPK-dependent mechanism. These findings further validate the potential benefits of metformin in the treatment of conditions associated with hyperinsulinemia and excessive growth of ovarian T-I cells (such as polycystic ovary syndrome).

The in utero programming effect of increased maternal androgens and a direct fetal intervention on liver and metabolic function in adult sheep

Epigenetic changes in response to external stimuli are fast emerging as common underlying causes for the pre-disposition to adult disease. Prenatal androgenization is one such model that results in reproductive and metabolic features that are present in conditions such as polycystic ovary syndrome (PCOS). We examined the effect of prenatal androgens on liver function and metabolism of adult sheep. As non-alcoholic fatty liver disease is increased in PCOS we hypothesized that this, and other important liver pathways including metabolic function, insulin–like growth factor (IGF) and steroid receptivity, would be affected. Pregnant ewes received vehicle control (C; n = 5) or testosterone propionate (TP; n = 9) twice weekly (100 mg; i.m) from d62–102 (gestation 147 days). In a novel treatment paradigm, a second cohort received a direct C (n = 4) or TP (20 mg; n = 7) fetal injection at d62 and d82. In adults, maternal TP exposure resulted in increased insulin secretion to glucose load (P<0.05) and the histological presence of fatty liver (P<0.05) independent of central obesity. Additionally, hepatic androgen receptor (AR; P<0.05), glucocorticoid receptor (GR; P<0.05), UDP- glucose ceramide glucosyltransferase (UGCG; P<0.05) and IGF1 (P<0.01) expression were upregulated. The direct fetal intervention (C and TP) led to early fatty liver changes in all animals without differential changes in insulin secretion. Furthermore, hepatic phosphoenolpyruvate carboxykinase (PEPCK) was up-regulated in the fetal controls (P<0.05) and this was opposed by fetal TP (P<0.05). Hepatic estrogen receptor (ERα; P<0.05) and mitogen activated protein kinase kinase 4 (MAP2K4; P<0.05) were increased following fetal TP exposure. Adult liver metabolism and signaling can be altered by early exposure to sex steroids implicating epigenetic regulation of metabolic disturbances that are common in PCOS.

Serum and follicular fluid levels of IGF-II, IGF-binding protein-4 and pregnancy-associated plasma protein-A in controlled ovarian hyperstimulation cycle between polycystic ovarian syndrome (PCOS) and non-PCOS women

OBJECTIVE

To investigate the difference of serum and follicular expression patterns for IGFα, IGFBP4 and PAPP-A in COH cycle between PCOS and non-PCOS women.

METHODS

COH was performed for total 30 sterile women (20 with PCOS and 10 with normal ovarian function). The serum and follicular fluid (FF)from dominant follicles levels of IGFα, IGFBP4 and PAPP-A before COH, day of hCG, and were measured using an ELISA.

RESULTS

The PCOS women had significantly higher day 3 serum PAPP-A, day of hCG serum IGFBP-4, and ff IGF-II levels compared to the normoovulatory subjects. Serum levels of IGF-II and IGFBP-4 in PCOS women had increased after gonadotropins stimulation, and yet PAPP-A was decreased. Within the PCOS women, day of hCG serum IGFBP-4 was strongly correlated with BMI (r=0.777; P=0.000), day of hCG IGF II (r= -0.573, p=0.008), ff IGF II (r= -0.573, p=0.008) and ff PAPP-A (r= -0.461, p=0.041) was inversely related to diameter >16 mm follicle number and day 3 PAPP-A correlated to diameter > 16 mm follicle number (r=0.474; p=0.035).

CONCLUSIONS

Ovarian IGF system on the gonadotropin response to differences in the PCOS and non-PCOS women in COH cycle, and may indicate a inordinate IGF system that might disturb folliculogenesis in PCOS women.

Implantation failure: molecular mechanisms and clinical treatment

BACKGROUND

Implantation is a complex initial step in the establishment of a successful pregnancy. Although embryo quality is an important determinant of implantation, temporally coordinated differentiation of endometrial cells to attain uterine receptivity and a synchronized dialog between maternal and embryonic tissues are crucial. The exact mechanism of implantation failure is still poorly understood.

METHODS

This review summarizes the current knowledge about the proposed mechanisms of implantation failure in gynecological diseases, the evaluation of endometrial receptivity and the treatment methods to improve implantation.

RESULTS

The absence or suppression of molecules essential for endometrial receptivity results in decreased implantation rates in animal models and gynecological diseases, including endometriosis, hydrosalpinx, leiomyoma and polycystic ovarian syndrome. The mechanisms are diverse and include abnormal cytokine and hormonal signaling as well as epigenetic alterations.

CONCLUSIONS

Optimizing endometrial receptivity in fertility treatment will improve success rates. Evaluation of implantation markers may help to predict pregnancy outcome and detect occult implantation deficiency. Treating the underlying gynecological disease with medical or surgical interventions is the optimal current therapy. Manipulating the expression of key endometrial genes with gene or stem cell-based therapies may some day be used to further improve implantation rates.

mRNA expression pattern of insulin-like growth factor components of granulosa cells and cumulus cells in women with and without polycystic ovary syndrome according to oocyte maturity

The mRNA expression of insulin-like growth factor (IGF) components was investigated in granulosa cells (GCs) and cumulus cells (CCs) sampled from immature and mature follicles in women with and without polycystic ovary syndrome (PCOS). Gene expression for IGF-binding protein (IGFBP) 3 in GCs definitely differed between normal women and women with PCOS, whereas increase in IGF-I and IGF receptor (IGFR) 2 mRNA in mature-follicle GCs, increase in IGF-II, IGFR-1, and IGFBP-4 mRNA in immature-follicle GCs, increase in IGFR-2 and IGFBP-2 mRNA in mature-follicle CCs, and increase IGFBP-6 mRNA in immature-follicle CCs were observed in both normal women and women with PCOS.

The effects of somatostatin in the polycystic ovary syndrome

Eighteen obese women (body mass index 30 +/- 6.1 kg/m2) with hyperinsulinaemia and with the polycystic ovary syndrome took octreotide at the dose of 100 mug s.c. The effect of the drug was assessed on plasma levels of gonadotropins luteinising hormone (LH), follicle stimulating hormone (FSH), of insulin, insulin-like growth factor-1 (IGF-1), androstenedione, testosterone, dehydroepiandrosterone sulphate (DHEAS), sex hormone binding globulin (SHBG) and insulin-like growth factor-binding protein-3 (IGFBP-3). Octreotide significantly reduced LH (31.8%), insulin (52%), IGF-1 (14%), androstenedione (22.6%) and testosterone (20%) and increased IGFBP-3 (25%).

Metformin in the treatment of clomiphene citrate-resistant women with high BMI and primary infertility: Clinical results and reproductive outcome

The objective of this study was to evaluate the clinical and reproductive outcome in clomiphene-citrate (CC)-resistant women with high body mass index (BMI) and primary infertility. This was a case series based at the King Hussein Medical center, Amman, Jordan. Nineteen CC-resistant women with polycystic ovary syndrome (PCOS) who had high BMI and primary infertility were studied. All women received metformin monotherapy; 850 mg twice daily for a period of 6 months. If pregnancy occurred, metformin was continued for the first 12 weeks of pregnancy. The main outcome measures were a reduction in the BMI, resumption of regular menses, ovulation and pregnancy rates. Resumption of regular cycles was observed in 13 of 19 (68.4%) women. Ovulation and pregnancy were achieved in 9 (47.4%) and 6 (31.6%) of the 19 women, respectively. A significant reduction in the body weight after treatment reflected by a significant reduction in the BMI was noted. Metformin monotherapy is effective in CC-resistant women with morbid obesity and primary infertility and should be considered as first-line treatment in these patients.

Diagnosis of metabolic disorders in women with polycystic ovary syndrome

Although there is a widespread on-going debate throughout the scientific community with regard to the pathogenesis of polycystic ovary syndrome, the association between this frequently observed endocrine disorder and insulin resistance has been universally acknowledged. Numerous tests have been proposed for use in assessing reduced sensitivity to insulin in women with polycystic ovary syndrome. The gold standard is represented by the euglycemic hyperinsulinemic clamp, although not yet available for application in routine clinical practice in view of its complexity and high cost. Measurement of oral glucose load and the use of several fasting tests feature a good degree of reliability and can be easily repeated. It remains to be ascertained, however, which therapeutic procedures, if any, are best suited for use in women affected by hyperinsulemia.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After reading this article, the reader should be able to outline metabolic consequences of polycystic ovarian syndrome (PCOS), conclude that testing insulin resistance is an important step in the care of women with PCOS, and recall the indications and limits of testing strategies for insulin resistance.

HMG-CoA reductase inhibitors: do they have potential in the treatment of polycystic ovary syndrome?

Many women of reproductive age are affected by polycystic ovary syndrome (PCOS), a heterogeneous endocrinopathy characterized by androgen excess, chronic oligo-anovulation and/or polycystic ovarian morphology. In addition, PCOS is often associated with insulin resistance, systemic inflammation and oxidative stress, which, on one hand, lead to endothelial dysfunction and dyslipidaemia with subsequent cardiovascular sequelae and, on the other hand, to hyperplasia of the ovarian theca compartment with resultant hyperandrogenism and anovulation. Traditionally, HMG-CoA reductase inhibitors (statins) have been used to treat dyslipidaemia by blocking HMG-CoA reductase (the rate-limiting step in cholesterol biosynthesis); however, they also possess pleiotropic actions, resulting in antioxidant, anti-inflammatory and anti-proliferative effects. Statins offer a novel therapeutic approach to PCOS in that they address the dyslipidaemia associated with the syndrome, as well as hyperandrogenism or hyperandrogenaemia. These actions may be due to an inhibition of the effects of systemic inflammation and insulin resistance/hyperinsulinaemia. Evidence to date, both in vitro and in vivo, suggests that statins have potential in the treatment of PCOS; however, further clinical trials are needed before they can be considered a standard of care in the medical management of this common endocrinopathy.

Statins in the treatment of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy affecting reproductive-aged women. The hyperandrogenemia associated with the syndrome is a result of excessive growth and steroidogenic activity of theca-interstitial tissues in response to various factors, including elevated gonadotropins, hyperinsulinemia, and oxidative stress. PCOS frequently coexists with other cardiovascular risk factors, such as dyslipidemia and systemic inflammation. Statins inhibit the synthesis of mevalonate, the key precursor to cholesterol biosynthesis, and reduce cardiovascular morbidity and mortality. Blockade of mevalonate production may also lead to decreased maturation of insulin receptors, inhibition of steroidogenesis (e.g., via limiting the amount of substrate: cholesterol), and alteration of signal transduction pathways that mediate cellular proliferation. The latter depend upon posttranslational modification of proteins (prenylation), a process mediated by mevalonate derivatives. Statins also have intrinsic antioxidant properties. Given the pleiotropic actions of statins, they are likely not only to improve the dyslipidemia associated with PCOS but may also exert other beneficial metabolic and endocrine effects.

Recurrent miscarriage: pathophysiology and outcome

PURPOSE OF REVIEW

This article reviews new concepts in the aetiology of recurrent miscarriage, presents new outcome data and evaluates new modalities of treatment for unexplained recurrent miscarriage.

RECENT FINDINGS

Preimplantation genetic diagnosis has been considered an option for couples who have structural chromosomal abnormalities or unexplained recurrent miscarriage. The association between thrombophilias and adverse pregnancy outcome is further reviewed. In relation to this, there is increasing support for the use of thromboprophylaxis in improving pregnancy outcome in women with inherited thrombophilias. Nonrandomized studies have shown that the reduction in insulin levels with metformin in insulin-resistant individuals may reduce miscarriage risk by restoring normal haemostasis and improving the endometrial milieu. With respect to immunological concepts there is now evidence to suggest that, in addition to a suppression of maternal cell-mediated immunity, some elements of the innate immune system are activated in successful pregnancies.

SUMMARY

With the exception of aspirin and heparin for the prevention of recurrent miscarriage in women with the antiphospholipid syndrome, no other suggested therapies for this heterogeneous group of patients have been evaluated in randomized controlled trials. These include thromboprophylaxis for inherited thrombophilias and use of insulin sensitizers in women with insulin resistance and/or polycystic ovarian syndrome. The role of the innate immune system in pregnancy was recently highlighted, and use of nonspecific therapies to suppress the maternal immune response to pregnancy should be reassessed.

Does plasma insulin level affect ovarian response to exogenous administration of follicle-stimulating hormone in women without polycystic ovary syndrome?

BACKGROUND

Raised insulin levels have been shown to contribute to ovarian overproduction of androgens. Hyperinsulinemia, usually associated with polycystic ovary syndrome (PCOS), brings about greater ovarian endocrine and morphological responses to ovulation induced by follicle-stimulating hormone (FSH). This indicates that elevated levels of insulin play a role in the endocrine and paracrine control of the ovaries.

OBJECTIVE

The aim of the present study was to investigate whether basal insulin levels influence ovarian response to FSH in healthy women (non-PCOS) undergoing assisted reproduction by in vitro fertilization-embryo transfer (IVF-ET).

METHODS

The study included 36 consecutive women, 27-45 years old, undergoing IVF-ET for tubal-factor or male-factor infertility. Serum insulin levels were determined on the day of administration of gonadotropin-releasing hormone analog (GnRHa) and on the first day of FSH administration.

RESULTS

Mean insulin levels were 6 +/- 3 and 7 +/- 3 microU/ml on the day of GnRHa and FSH administration, respectively. No correlations were found between basal insulin level, days of treatment, total FSH dose, estradiol level and the number of oocytes retrieved.

CONCLUSIONS

The results of the present study show that normal levels of insulin do not seem to influence ovarian response to FSH in non-PCOS women. In all patients included in our study, serum insulin levels did not correlate with IVF stimulation data (days of stimulation, total FSH dose) nor with IVF-ET outcome. Thus the study demonstrates that, in patients who are not insulin-resistant, insulin does not correlate with ovarian response to FSH administration.

The impact of insulin resistance on the outcome of laparoscopic ovarian electrocautery in infertile women with the polycystic ovary syndrome

In this study we assessed how insulin resistance affects pregnancy rates in infertile women with the polycystic ovary syndrome (PCOS) treated with laparoscopic ovarian electrocautery. Sixty-four PCOS women were included in the study in a consecutive fashion. Following the CIGMA (continuous infusion of glucose with model assessment) test, 28 women were classified as insulin resistant and 36 women as non-insulin resistant. After the ovarian electrocautery patients were observed for 12-18 months. If pregnancy did not ensue, they were referred for one or more cycles of in vitro fertilization (IVF). Following ovarian electrocautery the non-insulin-resistant women more frequently achieved a regular menstrual cycle and ovulation than the insulin-resistant PCOS women. Consequently 18 (50%) of the non-insulin-resistant PCOS women achieved a pregnancy versus only five (18%) of women in the insulin-resistant PCOS group. Following treatment with both ovarian electrocautery and IVF, 27 (75%) of the non-insulin resistant PCOS women achieved a successful pregnancy, while 13 (46%) of the insulin-resistant PCOS group achieved this. In conclusion, insulin resistance may be an important marker of a poor outcome of treatment in PCOS infertility. Further studies are needed to evaluate the possible effect of treatment alternatives to alleviate the unfavorable influences of insulin resistance and hyperinsulinemia on ovulation induction in PCOS women.

Metformin therapy increases insulin-like growth factor binding protein-1 in hyperinsulinemic women with polycystic ovary syndrome

OBJECTIVES

Polycystic ovary syndrome (PCOS) is associated with hyperandrogenism, insulin resistance, compensatory hyperinsulinemia, and increased levels of free insulin-like growth factor-I (IGF-I), presumably due to a decline in IGF binding protein 1 (IGFBP-1). This study was designed to evaluate effects of metformin therapy on serum levels of IGFBP-1 and IGF-I.

STUDY DESIGN

Twenty-seven obese, hyperandrogenic PCOS women with elevated fasting insulin were treated for 12 weeks with metformin (500 mg p.o., t.i.d.). Serum levels of insulin, testosterone, sex hormone binding globulin (SHBG), IGF-I, and IGFBP-1 were measured before and after treatment. Body mass index (BMI) and waist-to-hip ratio (WHR) were assessed at baseline and at the end of therapy.

RESULTS

Metformin therapy significantly increased IGFBP-1 concentration by 38% (P = 0.05) but had no demonstrable effect on the total IGF-I levels. Fasting insulin levels declined by 38% (P = 0.0001) while the glucose/insulin ratio increased by 72% (P = 0.0001) and quantitative insulin sensitivity check index (QUICKI) increased by 8% (P = 0.0001). Metformin treatment also significantly decreased testosterone (by 37%, P = 0.0001) and increased SHBG concentration (by 16%, P = 0.04). Multiple linear regression analysis revealed that baseline IGFBP-1 levels correlated inversely and independently with two baseline parameters: WHR (P = 0.003) and free testosterone index (P = 0.04).

CONCLUSIONS

The present study shows that metformin therapy not only restores normal levels of insulin and testosterone, but also decreases the pool of free-bioactive IGF-I by increasing the levels of circulating IGFBP-1. We provide further arguments in favor of metformin therapy in hyperinsulinemic women with PCOS.

Should insulin-sensitizing drugs be used in the treatment of polycystic ovary syndrome?

Insulin resistance is a central feature of polycystic ovary syndrome (PCOS). Hyperinsulinaemia contributes to anovulation, hyperandrogenism, infertility and early pregnancy loss in women with PCOS. Chronic hyperinsulinaemia also predisposes women with PCOS to increased risks of diabetes and cardiovascular events. Current data indicate that metformin, either as monotherapy or in combination with clomiphene in clomiphene-resistant patients, is an effective treatment for anovulation in PCOS. Initial evidence also suggests that insulin sensitizers may have a role in preventing early pregnancy loss. Of the available insulin-sensitizing agents, metformin has been the agent most frequently studied in PCOS, and has the least undesirable pregnancy safety profile. Ameliorating the metabolic syndrome associated with insulin resistance in PCOS with metformin may also prevent long-term cardiovascular and diabetes complications, pending further evidence. Based on these data, metformin should be a first-line therapy for women with PCOS.

Aspectos neuroendócrinos na síndrome dos ovários policísticos

A síndrome dos ovários policísticos (PCOS) é a endocrinopatia mais freqüente na mulher em idade reprodutiva. O quadro clínico é variável, mas em geral apresenta-se com hirsutismo, acne e/ou alopecia androgênica, anovulação crônica associada a distúrbio menstrual e infertilidade. A resistência insulínica pode estar presente em mais da metade dos casos, em especial nas pacientes obesas. A etiopatogenia ainda não foi totalmente esclarecida, mas mecanismos neuroendócrinos vêm sendo estudados nos últimos anos. Embora esteja bem estabelecida a presença de secreção inapropriada do eixo GnRH-LH em pacientes com PCOS, algumas delas, especialmente as obesas/hiperinsulinêmicas, exibem níveis normais de LH e uma atenuação de sua resposta aos testes de estímulo. Recentemente, descrevemos uma correlação negativa entre leptina e LH em pacientes com PCOS, sugerindo que a atenuação nos níveis de LH nestas pacientes possa estar relacionada a um estado de resistência à leptina. Por outro lado, evidências sugerem que o eixo somatotrófico participe também dos mecanismos fisiopatológicos envolvidos na PCOS. Dados recentes do nosso grupo demonstram que pacientes de peso normal e normoinsulinêmicas apresentam uma maior resposta do GH à clonidina do que pacientes com hirsutismo idiopático. Um mecanismo possível seria uma ação co-gonadotrófica do GH, contribuindo para o hiperandrogenismo clínico e a anovulação. Outra possibilidade é que a elevação da secreção de GH seja somente um epifenômeno vinculado ao aumento de androgênios ovarianos e sua conversão periférica em estrogênios. Estudos futuros são necessários para esclarecer os mecanismos subjacentes associados às alterações descritas neste trabalho e sua relevância na etiopatogenia, diagnóstico e tratamento desta síndrome.

Acne and hirsutism in polycystic ovary syndrome: clinical, endocrine-metabolic and ultrasonographic differences

The aim of this study was to investigate whether the absence or presence of acne or hirsutism in 248 women with polycystic ovary syndrome was associated with different clinical, endocrine, metabolic and ultrasonographic factors. Patients were divided into three groups: 96 (38.7%) without any androgenic symptoms; 94 (37.9%) with only hirsutism; and 58 (23.4%) with only acne. The cycle alterations (oligomenorrhea or amenorrhea) and the echographic ovarian morphology (polycystic or multifollicular ovaries) showed no significant differences between the three groups. Hirsutism was associated with a greater incidence of obesity and insulin resistance, with an increase of 17-hydroxyprogesterone, ovarian and adrenal androgens, 3alpha-androstanediol glucuronide, insulin, insulin-like growth factor-I and low luteinizing hormone, sex hormone binding globulins and insulin-like growth factor binding protein-1 levels. Acne was associated only with the lowest 3alpha-androstanediol glucuronide levels. Therefore, two different pathogenetic mechanisms may play a role in the onset of acne and hirsutism.

Insulin-lowering drugs in polycystic ovary syndrome

The discovery that insulin resistance has a key role in the pathophysiology of PCOS has led to a novel and promising form of therapy in the form of the insulin-sensitizing drugs. Although no extremely large trials using these drugs for this indication have been performed, more than 18 trials have specifically examined the effects of these drugs on ovulation, hyperandrogenemia, and dysmetabolic features in PCOS. Table 1 summarizes the results of previous trials using each of the insulin-sensitizing drugs discussed herein. Among the various agents (i.e., thiazolidinediones, [table: see text] metformin, and D-chiro-inositol), metformin is the most widely tested. Metformin may have the added benefit of improving at least some features of syndrome X, such as hypertension and obesity. All of the evidence to date suggests that metformin is a safe drug to administer to women who may become pregnant. In contrast, the two thiazolidinediones currently available, rosiglitazone and pioglitazone, are category C drugs that have been demonstrated to retard fetal development in animal studies. Overall, insulin-sensitizing therapy presents a promising and unique therapeutic intervention for the treatment of PCOS, offering metabolic and gynecologic benefits for women who sustain this syndrome.

Normal ovulatory women with polycystic ovaries have hyperandrogenic pituitary-ovarian responses to gonadotropin-releasing hormone-agonist testing

Women with polycystic ovary syndrome (PCOS) have chronic anovulation and hyperandrogenism and frequently have abnormalities in their lipid profiles and insulin/insulin-like growth factor axis that increase their lifetime risk for cardiovascular disease. Normal ovulatory women may have polycystic ovaries on ultrasonography and yet lack the clinical features of PCOS. To further explore whether ovulatory women without clinical/biochemical hyperandrogenism but with polycystic appearing ovaries (ov-PAO) have subclinical features of PCOS, we prospectively characterized 26 ov-PAO women and matched them by age and body mass index to 25 ovulatory women with normal appearing ovaries (ov-NAO) and to 22 women with PCOS. After an overnight fast, all women had baseline endocrine and metabolic assessments. In addition, a subset of each group of women underwent GnRH-agonist (leuprolide acetate 1 mg s.c.) testing, ACTH stimulation, and an insulin tolerance test (ITT). At baseline, ov-PAO and ov-NAO women had similar endocrine profiles (LH, LH:FSH, androstenedione, and DHEAS). Compared with ov-NAO, 31% of ov-PAO women had reduced glucose responses after insulin (K(itt)), suggesting mild insulin resistance, and 35% had high density lipoprotein levels below 35 mg/dL, a level considered to represent significant cardiovascular risk. After GnRH-agonist, ov-PAO women had response patterns in LH, total testosterone, and 17-hydroxyprogesterone (17-OHP) that were intermediate between ov-NAO and women with PCOS. Ovarian responses were above the normal range in 30-40% of women with ov-PAO. In ov-PAO, peak responses of LH after leuprolide correlated with triglyceride levels (P < 0.05) and peak responses of 17-OHP correlated inversely with Kitt values (P < 0.05). No significant differences were noted with ACTH testing. In conclusion, occult biochemical ovarian hyperandrogenism may be uncovered using GnRH-agonist in ovulatory women with ov-PAO, while adrenal responses remain normal. Subtle metabolic abnormalities may also be prevalent.

Synergistic effects of insulin-like growth factor-I and human chorionic gonadotropin in the rat ovary

Insulin and low doses of lutenizing hormone (LH) activity (human chorionic gonadotropin [hCG]) act synergistically in the rat to produce anovulation, large ovarian cysts, and elevated plasma androstenedione levels. Further, both insulin and insulin-like growth factor-I (IGF-I) affect the ability of gonadotropins to enhance both ovarian theca and granulosa cell function in vitro. The present series of experiments were performed to determine if recombinant human IGF-I (rhIGF-I) can act in a manner similar to insulin when combined with subovulatory doses of hCG in adult normally cycling rats. Fifty-four female Sprague-Dawley rats were randomly assigned to the following treatment groups at the age of 64 days: (A) vehicle alone (controls, phosphate-buffered saline containing 0.09% pig gelatin), (B) twice-daily subcutaneous injections of 0.5 to 3.0 U insulin, (C) twice-daily subcutaneous injections of 1.5 U hCG, (D) both insulin and hCG, (E) twice-daily subcutaneous injections of rhIGF-I (2.5 mg/kg/d), and (F) both hCG and rhIGF-I. After 22 days of treatment, the animals were killed on day 23, trunk blood was collected, and the ovaries were excised for histological study. Eight of 9 control rats and 5 or 6 of 9 rats treated with insulin, hCG, or rhIGF-I alone displayed normal estrus cycles throughout the in vivo treatment period as assessed by daily vaginal smears. In marked contrast, only 1 animal treated with hCG + insulin and 2 animals treated with hCG + rhIGF-I continued to display vaginal smears indicative of normal cycling. Multiple large ovarian follicular cysts were found only in these latter 2 groups (3 of 9 animals in each group). Mean serum testosterone levels were significantly elevated in animals receiving insulin + hCG (0.72 +/- 0.28 v 0.17 +/- 0.03 ng/mL in controls, P = .05). Mean serum androstenedione levels were significantly elevated in animals receiving hCG and animals receiving rhIGF-I + hCG (5.57 +/- 0.99 and 2.39 +/- 0.68 ng/mL, respectively, v0.14 +/- 0.14 ng/mL in controls, P< .01 and P< .05, respectively). We conclude that rhIGF-I and insulin act synergistically with subovulatory doses of hCG to disrupt normal reproductive cycling, elevate serum androgen concentrations, and induce large ovarian cysts in intact adult rats.

Growth factor action on ovarian function in polycystic ovary syndrome

Insulin-like growth factors, their receptors, binding proteins, and binding protein proteases are important in normal and abnormal ovarian follicle development. IGFs stimulate ovarian cellular mitosis and steroidogenesis and inhibit apoptosis. Patterns of expression of IGF family members are characteristic of whether follicles are estrogen- or androgen-dominant. The PCOS follicle is androgen-dominant but does not appear to be atretic and has characteristic IGF family expression. Available data strongly support an intraovarian, as opposed to endocrine, role for this growth factor family in ovarian follicle growth, steroidogenesis, and atresia.

Growth hormone and ovarian function

Growth and reproductive development are closely co-ordinated during puberty but there is also evidence that growth hormone (GH) may have a physiological role in adult ovarian function. Both GH and the insulin-like growth factors (IGFs) have been shown to augment granulosa cell proliferation and steroidogenesis in the human Graafian follicle, suggesting that GH may act as a 'co-gonadotrophin' at ovarian level. Furthermore, the intra-ovarian 'IGF system' (i.e. IGFs and IGF-binding proteins) may be implicated in folicular atresia and in disorders of follicular function associated with polycystic ovary syndrome (PCOS). The clinical importance of GH to ovarian function in the adult is illustrated by the finding that adjuvant GH treatment reduces the dose of exogenous gonadotrophin which is required to induce folliculogenesis in women with hypogonadotrophic hypogonadism. There is, however, no evidence that GH supplementation is of significant clinical benefit in the management of patients with other ovulatory disorders--including PCOS--or in superovulation protocols for in vitro fertilization.

Combined somatostatin analog and follicle-stimulating hormone for women with polycystic ovary syndrome resistant to conventional treatment

This study was undertaken to determine whether somatostatin analog in combination with human urinary follicle-stimulating hormone (FSH) improves ovulatory performance in patients with polycystic ovarian syndrome (PCOS) who failed to respond to FSH alone. A comparative prospective study was performed in six insulin-resistant, hyperandrogenic, PCOS women treated with somatostatin analog combined with FSH for one cycle. Individual ovulatory performance was compared to the cumulative ovulatory response of three previous cycles. Somatostatin analog was administered subcutaneously by means of an infusion pump, providing a total daily dose of 200 micrograms starting from days 1-3 of the cycle. Induction of ovulation with FSH was initiated on day 5 of the stimulated cycle. Vaginal ultrasonography for follicular surveillance was performed before the pump setting and during the treatment cycle. A significant decrease in insulin, insulin-like growth factor (IGF-I), growth hormone (GH) and luteinizing hormone (LH) was observed during the combined somatostatin analog-FSH treatment cycles. The follicular growth patterns and the incidence of ovarian hyperstimulation syndrome (OHSS) was not affected. These observations suggest that adjuvant therapy with somatostatin analog may have a beneficial effect on the hormonal response of PCOS patients to gonadotropin induction of ovulation.

Regulation of insulin-like growth factor-binding protein-1 and progesterone secretion from human granulosa-luteal cells: effects of octreotide and insulin

OBJECTIVE

To examine the effects of the synthetic somatostatin-analogue octreotide and human recombinant insulin on the release of insulin-like growth factor binding protein-1 (IGFBP-1) and P from human granulosa-luteal cells.

DESIGN

Primary culture of human granulosa-luteal cells.

SETTING

Academic research laboratory.

PATIENT(S)

Women undergoing oocyte retrieval for IVF-ET because of tubal infertility.

INTERVENTION(S)

Octreotide or insulin were added to the cultures; sampling of culture medium was performed after 48 hours.

MAIN OUTCOME MEASURE(S)

Insulin-like growth factor binding protein-1 and P.

RESULT(S)

Octreotide significantly inhibited IGFBP-1 (58.8% compared with controls) and P release (66.1% compared with controls). Insulin abolished IGFBP-1 release while stimulating P release (200.7% compared with controls). There was a significant and positive correlation between IGFBP-1 and P levels.

CONCLUSION(S)

Octreotide and insulin have a significant effect on human granulosa-luteal cell function in terms of IGFBP-1 and P release. Our results suggest a local ovarian mechanism for the recently observed effects of octreotide in the treatment of women with polycystic ovary syndrome.

Nutrition, hormones, and breast cancer: is insulin the missing link?

Breast cancer incidence rates are high in societies with a Western lifestyle characterized by low levels of physical activity, and by an energy-dense diet rich in total and saturated fat and refined carbohydrates. Epidemiologic studies, so far mostly on postmenopausal women, have shown that breast cancer risk is increased in hyperandrogenic women, with decreased levels of plasma sex-hormone binding globulin, and with increased levels of testosterone and of free estrogens. This paper describes the role of hyperinsulinemia as a physiologic link between nutritional lifestyle factors, obesity, and the development of a hyperandrogenic endocrine profile, and reviews evidence that may or may not support the theory that chronic hyperinsulinemia is an underlying cause of breast cancer. An hypothesis is presented, stipulating that breast cancer risk is increased not only in hyperandrogenic postmenopausal women, but also in premenopausal women with mild hyperandrogenism and normal (ovulatory) menstrual cycles. The author suggests further investigation as to whether there is a positive association between risk of breast cancer before menopause and subclinical forms of the polycystic ovary syndrome (PCOS), and to what extent diet and physical activity during childhood, by modulating the degree of insulin resistance during adolescence, may or may not be determinants of a PCO-like hyperandrogenic endocrine profile persisting into adulthood.

Hyperinsulinemia in the polycystic ovary syndrome: a clinical, endocrine and echographic study in 240 patients

In recent years numerous studies have suggested insulin to be an important regulator of ovarian function and hyperinsulinemia to be associated with hyperandrogenism. An oral glucose-tolerance test was carried out in 240 women with polycystic ovary syndrome and, based on its result, 142 of the women (59.2%) were insulin resistant or hyperinsulinemic and 98 (40.8%) were normoinsulinemic. Compared with the normoinsulinemic group, the hyperinsulinemic group had a greater incidence of obesity (52.8 vs. 21.4%), secondary amenorrhea (24.6 vs. 9.2%), androgenic symptoms (85.9 vs. 67.4%) and, in particular, hirsutism with or without acne (71.8 vs. 48.0%). Moreover, the hyperinsulinemic group had significantly higher plasma levels of androstenedione, testosterone, free testosterone and insulin, and lower levels of luteinizing hormone, estradiol and sex hormone-binding globulin.

Genetic and non-genetic theories on the etiology of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a common endocrine disorder; the precise cause of it remains elusive. This review summarizes the genetic and non-genetic theories that have been postulated to explain the etiology of this enigmatic condition.

Disturbances in insulin secretion and sensitivity in women with the polycystic ovary syndrome

Insulin resistance, defined as a diminished effect of a given dose of insulin on glucose homeostasis, is a highly prevalent feature of women with PCOS. Insulin resistance in PCOS is closely associated with an increase in truncal-abdominal fat mass, elevated free fatty acid levels, increased androgens, particularly free testosterone through reduced SHBG levels, and anovulation. The causes for insulin resistance in PCOS are still unknown. One line of evidence suggests that an increase in truncal-abdominal fat mass and subsequently increased free fatty acid levels induce insulin resistance in women with PCOS. Increased effects of corticosteroids and a relative reduction in oestrogen and progesterone seem to be involved in the aberrant body fat distribution. Conversely, there are also results supporting primary, genetic target cell defects as a cause of insulin resistance in PCOS. An explanation for these seemingly contradictory results could be that the group of women with PCOS is heterogeneous with respect to the primary event in carbohydrate/insulin disturbances. Also insulin secretion in PCOS is characterized by heterogeneity. At one end of the spectrum is a large subgroup of mainly obese women with reduced insulin secretion, which appears to result from failure of the beta cells to compensate for insulin resistance in susceptible women, resulting in glucose intolerance and NIDDM. In the insulin-resistant patients with normal glucose tolerance, most of the hyperinsulinaemia is probably due to secondarily increased insulin secretion and decreased insulin degradation. However, a component of the increased first-phase insulin release is not due to measurable insulin resistance. Notably, this is also found in lean women with normal insulin sensitivity, and is not reversed after weight reduction, in contrast to the findings for insulin resistance. The implications of this enhanced insulin release are not fully clear, but it may tentatively be associated with carbohydrate craving and subsequently increased risks for development of obesity and insulin resistance. It may represent a primary disturbance of insulin secretion in PCOS or may be associated with the perturbed steroid balance in anovulation. The insulin-androgen connection in PCOS appears to be amplified by several different mechanisms, notably in both directions, the initiating event probably varying between individuals. Thus insulin increases the biological availability of potent steroids, primarily testosterone, through the suppression of SHBG synthesis. Insulin is also involved as a progonadotrophin in ovarian steroidogenesis, with the possible net result of interfering with ovulation and/or increasing ovarian androgen production in states of hyperinsulinaemia. Conversely, testosterone may indirectly contribute to insulin resistance through facilitating free fatty acid release from abdominal fat, but perhaps also through direct muscular effects at higher serum levels. It seems likely that this constitution, presumably genetic, would provide evolutionary advantages in times of limited nutrition, given the energy-saving effects of insulin resistance. Hypothetically, hyperinsulinaemia (primary) could provide a stimulus to ensure intake of nourishment, but unlimited food supplies could in some cases initiate a vicious 'anabolic' circle, in which several of the proposed amplifying mechanisms between insulin and androgens--in both directions--could take part.

Insulin resistance, insulin-like growth factor I and breast cancer: a hypothesis

Consideration of existing data regarding clinical and biochemical risk factors for the development of breast cancer leads to the hypothesis that enhanced insulin-like growth factor I (IGF-I) activity plays a significant role in the development of this disease. Abnormal IGF-I activity may be related to events occurring prenatally, during puberty, or during adult life. Insulin resistance, a common feature in populations characterized by high caloric intake, may result in the amplification of IGF-I action at the tissue level by altering serum concentrations of IGF-I binding proteins. Several approaches toward testing the hypothesis are proposed, and potential opportunities for clinical application are described.

Diurnal variation of sex hormone binding globulin and insulin-like growth factor binding protein-1 in women with polycystic ovary syndrome

OBJECTIVES

The aim of this study was to examine (1) the diurnal variation in SHBG and (2) the inter-relationships of insulin, IGF-I, SHBG and IGFBP-1 over 24 hours in 10 women with anovulatory PCOS and compare them with weight-matched ovulatory controls.

PATIENTS AND METHODS

The two groups comprised 10 anovulatory women with PCOS (as defined by clinical, ultrasound and biochemical criteria) and 10 weight matched controls. Serum samples were taken at two-hourly intervals for 24 hours and stored for measurement of SHBG, IGFBP-1, insulin and IGF-I. Differences between the groups were compared using the Wilcoxon ranked paired tests of the individual peak and trough concentrations in each group. The variation in insulin, IGFBP-1 and SHBG concentrations over 24 hours was tested using two-way analysis of variance with the factors time and subject. Spearman's correlation coefficient was calculated from the subjects' median value over 24 hours.

RESULTS

The median (interquartile range) body mass index (BMI) was 25.2 (22.2-29.3) in the PCOS group and 24.3 (23.2-25.7) kg/m2 in the control group. Serum testosterone (T) and LH levels were significantly raised in the PCOS group compared to the control group; T 3.8 (2.9-5.6) vs 1.9 (1.9-2.5) nmol/l (P < 0.007) and LH 12 (10-15) vs 4.1 (3.6-4.5) IU/I (P < 0.005) respectively. There was no diurnal variation in SHBG. The median (interquartile ranges) of the peak SHBG concentrations was lower in the PCOS group: 29.4 (14.9-39.4) vs 52.1 (39.4-61) nmol/l in the control group (P < 0.01). The fasting levels of insulin at 0600 h (median (interquartile ranges)) were not significantly different between the groups; 6.6 (5.4-9.8) and 6.2 (1.9-7.6) mU/l, respectively, although the peak median concentrations were significantly different; PCOS 66.1 (50.9-129.2) vs 40 (36.1-74.2) mU/l (P < 0.05). Two-way analysis of variance showed a diurnal variation in insulin concentrations in the control group (P = 0.001) but not in the PCOS group (P = 0.1). The diurnal variation in IGFBP-1 was similar in the two groups but the peak median levels were lower in the women with PCOS 54.9 (22.3-79.2) vs 71.5 (60.5-99.3) micrograms/l (P < 0.03). The decline in IGFBP-1 concentrations correlated with the increase in insulin concentrations. The IGF-I concentrations were similar in the two groups. There was a significant negative correlation between SHBG and insulin (P < 0.05) and between insulin and IGFBP-1 (P < 0.01).

CONCLUSION

This study demonstrates that there is no diurnal variation in SHBG concentrations and confirms the finding of a marked diurnal variation in the concentration of IGFBP-1. Women with PCOS who are anovulatory have an abnormal pattern of insulin secretion with an absence of diurnal variation compared to weight matched controls. This provides further evidence of the relative insulin resistance which is independent of weight found in women with anovulatory PCOS. The inverse correlations of insulin concentrations with SHBG and IGFBP-1 support the role of insulin as a possible regulator of the circulating levels of these binding proteins although the difference in the time course of their response makes it unlikely that they are co-regulated.

Dysfunction of the growth hormone/insulin-like growth factor-I axis in women with polycystic ovarian syndrome

OBJECTIVE

Although a defect in GH regulation has been suggested in women with polycystic ovarian syndrome (PCOS), the data are limited and mechanism obscure. We have assessed the function of the GH/IGF-I axis in women with PCOS by measuring basal IGF-I levels and the ability of the pituitary to secrete GH following dopamine and GHRH.

DESIGN

For each woman the complete study lasted 3 days. On the 1st and 2nd days, saline (0.9%, 5 ml/h for 3 h) and dopamine (4 micrograms/kg/min for 3 h) infusion tests were performed, respectively, in all PCOS and control women. Blood samples for GH measurement were obtained before and at 20-minute intervals for 3 hours. On the 3rd day a GHRH test (100 micrograms, i.v. bolus) was performed in 9 of the women with PCOS and in 9 controls. Blood samples for GH measurements were obtained before and at 20-minute intervals for 3 hours. Basal IGF-I levels were measured in the basal blood samples from the saline infusion test in all patients studied.

SUBJECTS

Thirteen women with PCOS and 11 normally menstruating women (control group), aged 18-35 years, were studied. All women with PCOS had hirsutism and oligomenorrhoea since menarche, elevated serum values of at least one ovarian androgen and the typical ultrasound appearance of PCOS.

RESULTS

Growth hormone releasing hormone (GHRH) induced a significant increase in GH secretion in both control and PCOS groups. However, the GH response to GHRH was found to be significantly lower in women with PCOS. The 3-hour infusion of dopamine induced a significant increase in GH levels only in the control group, while it failed to stimulate GH release in the women with PCOS. Although both dopamine and GHRH failed to induce a normal GH response in women with PCOS, their IGF-I levels did not differ significantly from those observed in control women.

CONCLUSIONS

The diminished GH responses to both GHRH and dopamine in women with PCOS, in the presence of normal circulating IGF-I levels, suggests a dysregulation in GH secretion. Although the data are suggestive of a hypothalamic defect, further studies are required to clarify the underlying mechanism and the role, if any, of GH in the pathogenesis of polycyctic ovarian syndrome.

Alterations in the sensitivity of serum insulin-like growth factor 1 and insulin-like growth factor binding protein-3 to octreotide in polycystic ovary syndrome

OBJECTIVE

To determine if the somatostatin analog, octreotide, affects insulin and related peptides and, hence, androgen levels differently between polycystic ovary syndrome (PCOS) patients and controls.

DESIGN

Prospective controlled trial.

SETTING

Reproductive endocrinology clinic of our medical center.

PATIENTS

Eleven women with PCOS and six matched ovulatory controls.

INTERVENTIONS

Octreotide (100 micrograms) was administered subcutaneously in the midfollicular phase. Serum was obtained before and at 60, 120, 180, and 240 minutes after octreotide.

MAIN OUTCOME MEASURES

Fasting insulin, insulin-like growth factor 1 (IGF-1), insulin-like growth factor binding protein-3 (IGFBP-3), T, androstenedione (A), and LH.

RESULTS

In PCOS, baseline levels of T, A, LH, and fasting insulin were significantly higher than in controls. Pretreatment IGF-1 and IGFBP-3 levels were similar in PCOS and controls. Octreotide reduced fasting insulin levels significantly but to a similar degree in control and PCOS patients (77% and 90%, respectively). Both groups also experienced a significant decrease in LH levels after octreotide administration, but no significant changes were demonstrated in serum T or A. However, serum IGF-1 suppression in PCOS was greater (63% versus 8% in controls). Serum IGFBP-3 levels increased after octreotide administration in both groups with a larger increase (40%) occurring in the PCOS patients.

CONCLUSIONS

These data suggest that women with PCOS may be more sensitive to the effects of octreotide in decreasing IGF-1 and increasing IGFBP-3. Although no significant changes could be demonstrated in ovarian androgens after a single dose, octreotide effectively reduced serum LH and insulin and, as such, may prove useful in treating some patients with PCOS.

The relationship between circulating androgens, obesity, and hyperinsulinemia on serum insulin-like growth factor binding protein-1 in the polycystic ovarian syndrome

OBJECTIVE

Our purpose was to evaluate the relationship of obesity, hyperinsulinemia, and hyperandrogenemia on serum insulin-like growth factor binding protein-1 levels in women with the polycystic ovarian syndrome.

STUDY DESIGN

Insulin-like growth factor binding protein-1, insulin, and androgen levels were studied during a 3-hour intravenous glucose tolerance test in 16 women with polycystic ovarian syndrome (nine obese and seven nonobese) and 20 healthy control women (10 obese and 10 nonobese).

RESULTS

Positive correlations were observed between basal (r = 0.77, p = 0.04) and area under curve (r = 0.86, p < 0.001) insulin-like growth factor binding protein-1 with basal androstenedione in the nonobese women with polycystic ovarian syndrome but not in other groups of women examined or between other androgens and insulin-like growth factor binding protein-1. An inverse relationship was observed between log area under curve insulin-like growth factor binding protein-1 levels and log body mass index in polycystic ovarian syndrome (r = -0.54, p = 0.03) and in normal women (r = -0.43, p = 0.06). The log area under curve insulin-like growth factor binding protein-1 level was approximately an inverse linear function of log area under curve insulin response for both women with polycystic ovarian syndrome (r = -0.70, p < 0.001) and control women (r = -0.72, p < 0.001). Additionally, after the area under curve insulin response during intravenous glucose tolerance testing was controlled for, the decline in area under curve insulin-like growth factor binding protein-1 responses was on average 66% less in both obese and nonobese women with polycystic ovarian syndrome compared with same-weight controls (95% confidence interval 110% to 270%, p = 0.04).

CONCLUSION

These data indicate that insulin and body mass index are the major determinants of circulating insulin-like growth factor binding protein-1 and that chronic hyperandrogenemia does not appear to further reduce serum insulin-like growth factor binding protein-1 levels in obese or normal-weight women with polycystic ovarian syndrome.

Insulin-like growth factors: clinical experience in ovarian function

Insulin, insulin-like growth factor, and insulin-like growth factor binding proteins have been shown to play major roles in the modulation of both normal and disturbed ovarian physiology. Identification of many of the actions of these peptides was initially characterized using animal models. However, an increasing body of evidence has emerged to clarify their contributions in human reproductive function. It is clear that at various stages of folliculogenesis, local steroid production acts in concert with intraovarian peptides to promote dominant follicle development. This review will discuss the physiologic role(s) of the insulin-insulin-like growth factor-insulin-like growth factor binding protein family in reproductive function and disorders of androgen excess.

Clinical implications of hyperinsulinaemia in women

In the polycystic ovary syndrome, hyperinsulinaemia is commonly found in women with hirsutism, oligomenorrhoea and acanthosis nigricans and this subset of patients possess adverse risk factors for coronary artery disease, particularly reduced HDL2 concentrations. Conversely, raised serum insulin concentrations are not common in women with PCOS in whom raised serum LH concentrations or regular menstrual cycles are present. We postulate that both direct ovarian and indirect actions of insulin (through changes in IGFI-I, IGFBP-I and SHBG concentrations) play important roles in determining androgen concentrations in women. Many intriguing questions follow from this link between the control of nutrition and reproduction and many old observations required re-examination in this new light. Vital to our understanding in this field will be the cause of moderate hyperinsulinaemia, the action of insulin on the normal ovary, and the importance of adverse surrogate risk factors for heart disease in hyperinsulinaemic women.

Relationship between follicular fluid levels of insulin-like growth factor binding protein-1 and sex steroids from normal human ovarian follicles

The aim of this study was to examine the possible correlations between follicular fluid insulin-like growth factor binding protein 1 (IGFBP-1) and follicular fluid and serum parameters of granulosa cell function. Twenty-six subjects undergoing diagnostic laparoscopy for infertility had follicular fluid samples collected. Subjects were aged 20-42 years, were having regular ovulatory cycles and either had tubal disease or a partner with male factor infertility. Sex steroids, insulin-like growth factor 1 (IGF-1) and IGFBP-1 were measured by radioimmunoassay. Follicular fluid levels of IGFBP-1 were significantly correlated with levels of estradiol, progesterone in follicular fluid and with serum IGFBP-1 levels, and negatively correlated with follicular fluid androstenedione levels. These results suggests that IGFBP-1 may have a role in the regulation of human ovarian follicles.

Ovarian electrocauterization causes LH-regulated but not insulin-regulated endocrine changes

OBJECTIVE

We studied the effects of ovarian electrocauterization on the serum levels of luteinizing hormone (LH), testosterone, insulin, sex hormone-binding globulin (SHBG) and insulin-like growth factor binding globulin-1 (IGFBP-1) in women with polycystic ovarian disease (PCOD).

DESIGN

Prospective.

PATIENTS

Ten women with PCOD admitted to a University Infertility Clinic.

MEASUREMENTS

Fasting blood samples for determination of hormone levels were taken during the follicular phase before and one month after laparoscopic ovarian electrocauterization.

RESULTS

One month after electrocauterization the serum mean +/- SE LH levels had decreased from 14.4 +/- 1.9 to 10.9 +/- 1.1 U/l (P < 0.05), while the serum insulin levels showed no significant change (10.3 +/- 2.0 and 8.1 +/- 1.3 mU/l). The levels of IGFBP-1 (33.9 +/- 8.2 and 38.4 +/- 13.7 micrograms/l) and SHBG (48 +/- 10.4 and 43 +/- 5.7 nmol/l) showed no significant changes. Testosterone decreased from 3.9 +/- 2.6 to 2.9 +/- 0.3 nmol/l (P < 0.001) and androstenedione from 15.0 +/- 1.2 to 12.0 +/- 1.5 nmol/l (P = 0.05). After electrocautery seven out of ten PCOD patients ovulated either spontaneously (n = 3) or with clomiphene citrate (n = 4), and two of them conceived.

CONCLUSIONS

Ovarian electrocautery leads to resumption of ovulatory cycles in some but not all PCOD patients. This effect seems to be mediated by reduction of serum LH and androgen levels, while the insulin-driven pathway via SHBG and IGFBP-1 remains unaffected.

Serum levels of insulin-like growth factor binding protein-1 and ovulatory responses to clomiphene citrate in women with polycystic ovarian disease

OBJECTIVE

To study the serum levels of insulin, insulin-like growth factor I (IGF-I), and insulin-like growth factor binding protein-1 (IGFBP-1) in relation to clomiphene citrate (CC) responsiveness in women with polycystic ovarian disease (PCOD).

DESIGN

Prospective. PATIENTS, SETTING: Twenty-three women with PCOD admitted consecutively to the University Infertility Clinic, a tertiary referral center.

INTERVENTIONS

Blood samples were taken at fasting state and during oral glucose tolerance test (OGTT) for the determination of insulin, IGF-I, and IGFBP-1. A dose of 50 to 200 mg/d CC was given for ovulation induction.

RESULTS

With CC treatment, ovulation was achieved in 13 of 23 PCOD patients. The IGFBP-1 concentration was lower in CC nonresponders than in CC responders (20.5 +/- 4.0 ng/mL versus 41.0 +/- 8.5 ng/mL) (P < 0.05). This difference was accentuated in 13 lean PCOD patients. Lean CC nonresponders (n = 7) had almost threefold lower serum IGFBP-1 levels than lean CC responders (n = 6) (24.0 +/- 3.1 ng/mL versus 61.8 +/- 8.6 ng/mL) (P < 0.01). By contrast, among 10 obese PCOD patients, the IGFBP-1 levels were low irrespective of CC responsiveness (14.8 +/- 8.0 ng/mL versus 16.7 +/- 7.2 ng/mL). The differences remained during OGTT. The concentrations of IGF-I, insulin, sex hormone-binding globulin, LH, FSH, and androgens showed no significant differences between CC responders and nonresponders. There was an inverse correlation between serum insulin and IGFBP-1 levels in obese PCOD patients, whereas this was not seen in lean patients.

CONCLUSION

In lean PCOD patients, low serum IGFBP-1 concentration is related to CC unresponsiveness by a mechanism unrelated to insulin.