The endometrium in polycystic ovary syndrome:

Hyperinsulinemia impairs decidualization via AKT-NR4A1 signaling: new insight into polycystic ovary syndrome (PCOS)-related infertility

BACKGROUND

Investigating the underlying molecular mechanisms responsible for endometrial dysfunction in women with PCOS is essential, particularly focusing on the role of hyperinsulinemia.

METHODS

We explored the role of insulin in the decidualization process using a synthetic decidualization assay. To dissect the effects of PI3K/AKT-NR4A signaling, we employed small interfering RNAs (siRNAs) targeting the NR4A genes and inhibitors of the PI3K/AKT pathway. We also investigated the disruption of AKT-NR4A1 signaling in the endometrium of PCOS female rats induced with dehydroepiandrosterone (DHEA). Quantitative real-time PCR (qRT-PCR) and Western blot (WB) analyses were utilized to evaluate gene expression regulation.

RESULTS

Insulin was found to suppress the expression of decidualization markers in human endometrial stromal cells (hESC) in a dose-dependent manner, concurrently triggering an inappropriate activation of the PI3K/AKT pathway. Members of the NR4A family, as downstream effectors in the PI3K/AKT pathway, were implicated in the insulin-induced disruptions during the decidualization process. Moreover, the endometrium of PCOS models showed significantly elevated levels of phosphorylated (Ser473) AKT, with a corresponding reduction in Nr4a1 protein.

CONCLUSIONS

Our research demonstrates that insulin negatively regulates decidualization in hESC via the PI3K/AKT-NR4A pathway. In vivo analysis revealed a significant dysregulation of the AKT-NR4A1 pathway in the endometrium of PCOS rats. These findings offer novel insights into the pathogenesis of infertility and endometrial disorders associated with hyperinsulinemia in PCOS.

Fertility in Acromegaly: A Single-Center Experience of Female Patients During Active Disease and After Disease Remission

CONTEXT

Fertility represents a major concern in patients with acromegaly.

OBJECTIVE

The current retrospective study aimed to investigate gonadal function and fertility rates in acromegalic women.

METHODS

In this referral-center study, 50 acromegalic women with disease onset within reproductive age were evaluated for prevalence of gonadal dysfunction and infertility. Anthropometric, metabolic, hormonal parameters, and gynecological ultrasound were evaluated at diagnosis and after disease control. Data about menstrual disturbances, pregnancy, and polycystic ovarian morphology (PCOM) were investigated at disease onset, at diagnosis, and after disease control.

RESULTS

At presumed disease onset, menstrual disturbances were reported in 32% of patients. Uterine leiomyoma, ovarian cysts, and PCOM were diagnosed in 18%, 12%, and 8%, respectively; 36.8% of patients were infertile. At diagnosis, menstrual disturbances were found in 58.1% (P = .02), being significantly more prevalent in patients with higher insulin-like growth factor-I quartiles (Q) (P = .03, Q1 vs Q4). Gynecological ultrasound revealed uterine leiomyoma, ovarian cysts, and PCOM in 39.1% (P = .04), 28.2% (P = .09), and 13% (P = .55), respectively. The infertility rate was 100% (P = .02). At disease control, menstrual disturbances were slightly decreased as compared to diagnosis (P = .09). Noteworthy, menstrual disturbances (P = .05) and particularly amenorrhea (P = .03) were significantly more frequent in patients with active disease duration greater than 5 years (median) as compared to those achieving disease control in less than 5 years. Among patients with pregnancy desire, 73.3% conceived at least once, with resulting infertility significantly decreased compared to diagnosis (26.7%; P = .01). At-term deliveries, preterm deliveries, and spontaneous abortions were recorded in 86.7%, 6.6%, and 6.6%, respectively, of the 15 pregnancies reported by the patients. No neonatal malformations and/or abnormalities were recorded.

CONCLUSION

Gonadal dysfunction and infertility are common in acromegalic women within reproductive age, being directly influenced by disease status and/or duration.

Letrozole stimulation in endometrial preparation for cryopreserved-thawed embryo transfer in women with polycystic ovarian syndrome: a pilot study

OBJECTIVE

To study the efficiency of letrozole, an aromatase inhibitor, in endometrial preparation for cryopreserved-thawed embryo transfer (FET) in women with polycystic ovarian syndrome (PCOS).

DESIGN

Retrospective observational study.

PATIENTS

One hundred and twenty patients with PCOS who met the inclusion criteria for the study.

MEASUREMENTS

We assessed in vitro fertilization outcomes in one hundred and twenty patients with PCOS (148 cycles) who were prepared for and underwent FET between June 2011 and December 2012. Patients were prepared for FET using artificial hormone cycles induced with oestrogen and progesterone supplementation (n = 76), letrozole stimulation (n = 40) or hMG stimulation (n = 32).

RESULTS

There were no differences in demographic characteristics between the groups, except that the letrozole group had a higher incidence of embryo transfer failure in the past. The letrozole stimulation group had a significantly higher maximal endometrial thickness and significantly higher rates of clinical pregnancy per transfer, ongoing pregnancy per transfer and implantation, compared with the artificial and hMG stimulation groups. Differences in these parameters between the artificial and hMG stimulation groups were not significant.

CONCLUSION

Using letrozole stimulation in endometrial preparation for cryopreserved-thawed embryo transfer in patients with PCOS may be associated with better outcomes than using hormonal manipulation or hMG stimulation.

Increased apoptosis in bovine blastocysts exposed to high levels of IGF1 is not associated with downregulation of the IGF1 receptor

The hypothesis that high concentrations of IGF1 can impair embryo development was investigated in a bovine in vitro model to reflect conditions in polycystic ovary syndrome (PCOS) patients. Embryos were either cultured in the absence or presence of a physiological (100 ng/ml) or supraphysiological (1000 ng/ml) IGF1 concentration. Cell allocation, apoptosis, transcript and protein expression of selected genes involved in apoptosis, glucose metabolism and the IGF system were analysed. Supraphysiological IGF1 concentration did not improve blastocyst formation over controls, but induced higher levels of apoptosis, decreased TP53 protein expression in the trophectoderm and increased the number of cells in the inner cell mass (ICM). The increase in ICM cells corresponded with an increase in IGF1 receptor (IGF1R) protein in the ICM. A small, but significant, percentage of blastocysts displayed a hypertrophic ICM, not observed in controls and virtually absent in embryos treated with physiological concentrations of IGF1. Physiological IGF1 concentrations increased total IGF1R protein expression and upregulated IGFBP3 transcripts leading to an increase in blastocyst formation with no effects on cell number or apoptosis. In conclusion, the results support the hypothesis of detrimental effects of supraphysiological IGF1 concentrations on early pregnancy. However, our results do not support the premise that increased apoptosis associated with high levels of IGF1 is mediated via downregulation of the IGF1R as previously found in preimplantation mouse embryos. This in vitro system with the bovine preimplantation embryo reflects critical features of fertility in PCOS patients and could thus serve as a useful model for in-depth mechanistic studies.

Endometrium in PCOS: Implantation and predisposition to endocrine CA

Polycystic ovarian syndrome (PCOS) is a common endocrinopathy characterized by oligo/anovulatiaon and elevated circulating androgens or evidence of hyperandrogenism after all known potential causes have been excluded. In addition, insulin resistance and accompanying hyperinsulinemia commonly occur in women with PCOS. There is increasing evidence that the endocrinologic and metabolic abnormalities in PCOS may have complex effects on the endometrium, contributing to the infertility and endometrial disorders observed in women with this syndrome. Androgen receptors and steroid receptor co-activators are over-expressed in the endometrium of women with PCOS. Also, biomarkers of endometrial receptivity to embryonic implantation-such as alpha(v)beta3-integrin and glycodelin-are decreased, and epithelial expression of estrogen receptor alpha (ERalpha) abnormally persists in the window of implantation in endometrium in women with PCOS. In addition to being responsive to the steroid hormones estradiol, progesterone, and androgens, the endometrium is also a target for insulin, the receptor for which is cyclically regulated in normo-ovulatory women. In vitro, insulin inhibits the normal process of endometrial stromal differentiation (decidualization). In addition, insulin-like growth factors (IGFs) and their binding proteins are regulated in and act on endometrial cellular constituents, and hyperinsulinemia down-regulates hepatic IGFBP-1, resulting in elevated free IGF-I in the circulation. Thus, elevated estrogen (without the opposing effects of progesterone in the absence of ovulation), hyperinsulinemia, elevated free IGF-I and androgens, and obesity all likely contribute to endometrial dysfunction, infertility, increased miscarriage rate, endometrial hyperplasia, and endometrial cancer common in women with PCOS. The potential mechanisms underlying these disorders, specifically in women with PCOS, are complex and await additional transdisciplinary research for their complete elucidation.

Significance of progesterone receptor-A and -B expressions in endometrial adenocarcinoma

The progesterone receptor (PR) has two isoforms, A and B, among which PR-B is mainly involved in regulating proliferation of the uterine endometrium. In this study, immunohistochemical analysis was carried out to investigate the correlation of PR-A and -B expressions with cell cycle-regulatory proteins and clinicopathological parameters in endometrial adenocarcinoma. One hundred and forty-one endometrioid adenocarcinomas [76 with well-differentiated (G1), 35 with moderately differentiated (G2) and 30 with poorly differentiated (G3)] were used. Specimens of formalin-fixed and paraffin-embedded tissue were immunohistochemically stained using the high polymer method (HISTOFINE, NICHIREI). The percentage of positive nuclei of tumor cells observed in three high power fields was expressed as a labeling index (LI). PR-B expression significantly occurred more frequently in G1. It was inversely correlated with p53 gene mutation and p53 over expression, and also with clinicopathological variables, including myometrial and lymph-vascular space invasion and the FIGO stage. Patients with negative PR-B had a poorer prognosis than positive cases. PR-A expression was also significantly higher in G1 and was inversely correlated with Ki-67 expression and myometrial invasion, but not with prognosis. PR-A and -B expressions were significantly correlated with biologically malignant potential. Especially, PR-B expression is useful as a prognostic indicator of endometrial adenocarcinoma.