Differential expression of endometrial integrins and progesterone receptor during the window of implantation in normo-ovulatory women treated with clomiphene citrate

Recent clomiphene citrate exposure does not impact subsequent clinical outcomes in single euploid frozen embryo transfer cycles

STUDY QUESTION

Do infertile couples who recently utilized clomiphene citrate (CC) for ovulation induction or ovarian stimulation (<90 days previously) followed by a single euploid embryo transfer (SEET) have lower implantation potential compared with patients who were not exposed to CC within 90 days before embryo transfer (ET)?

SUMMARY ANSWER

There does not appear to be an association between recent CC exposure and lower implantation potential in patients who undergo a frozen embryo transfer (FET) of euploid embryos.

WHAT IS KNOWN ALREADY

Clomiphene has been found to be associated with lower pregnancy rates when compared against other ovarian stimulation medications. The majority of published research about the effects of CC on implantation potential suggest an anti-estrogenic effect on the endometrium. Quality evidence and information about utilization of CC and its effect on implantation potential after euploid ETs is lacking in the literature.

STUDY DESIGN, SIZE, DURATION

A retrospective cohort study with propensity score matching was carried out. We included all patients that underwent an autologous SEET from September 2016 to September 2022 at a single academic-private ART center.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The study group included patients that had utilized CC during either ovulation induction cycles and/or controlled ovarian stimulation at least 90 days before FET. A propensity score-matched control group of patients that were unexposed to CC within 90 days prior to SEET was used for comparisons. The primary outcome was positive pregnancy test (defined as a positive serum β-hCG measured 9 days after ET), with other outcomes including clinical pregnancy, ongoing pregnancy, biochemical pregnancy loss, and clinical pregnancy loss rates per SEET. Multivariate regression analyses fitted with generalized estimating equations were utilized to analyze if there was an association between CC utilization and IVF outcomes. Furthermore, the study evaluated the cumulative effect of CC and endometrial receptivity in vivo and subsequent IVF outcomes.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 593 patients with utilization of CC in <90 days before ET were compared with 1779 matched controls. Positive pregnancy test rates were comparable among the control group and the CC exposed groups, respectively (74.3% versus 75.7%, P = 0.79), as were clinical pregnancy (64.0% versus 65.0%, P = 0.60), ongoing pregnancy (51.8% versus 53.2%, P = 0.74), biochemical pregnancy loss (15.7% versus 14.03%, P = 0.45), and clinical pregnancy loss rates were also comparable among cohorts (17.1% versus 18.1%, P = 0.71). No association was found between utilization of clomiphene and lower implantation rates (adjusted odds ratio 0.95, 95% CI 0.76-1.18). Also, no differences were observed in sub-analyses based on multiple CC utilization periods. Finally, no association was found between the number of consecutive cumulative clomiphene cycles and sub-optimal IVF outcomes.

LIMITATIONS, REASONS FOR CAUTION

The study has inherent bias that originated from its retrospective design. Serum levels of CC were not measured and sample size for the sub-analyses was small.

WIDER IMPLICATIONS OF THE FINDINGS

There does not appear to be an association between recent CC exposure and lower implantation potential in patients who undergo a FET of euploid embryos. This finding remains consistent, even in patients who undergo multiple, consecutive clomiphene cycles prior to ET. There were no long-term effects of CC on endometrial development and clinical characteristics examined in this study. Patients that utilized CC medication prior to a SEET cycle for either ovarian stimulation or ovulation induction, can be assured that there is no evidence of a residual effect of recent CC administration that could jeopardize their pregnancy probability.

STUDY FUNDING/COMPETING INTEREST(S)

No funding was received for the realization of this study. A.C. is advisor and/or board member of Sema4 (stakeholder in data) and Progyny. The other authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Human implantation: The complex interplay between endometrial receptivity, inflammation, and the microbiome

Human embryo implantation is an intricate spatiotemporal process that involves the intimate association between the embryo and the endometrium of the mother. During implantation, the endometrium undergoes a dynamic cascade of gene activation and repression, largely driven by autocrine, paracrine, and endocrine action. Steroid hormones, such as estrogen and progesterone, act on a variety of targets including cellular adhesion molecules (CAMs), cytokines, and growth factors to facilitate the implantation process. Given the synchrony required to achieve implantation, it is unsurprising that embryo implantation represents a substantial problem for infertility patients. This is due to a complex interplay taking place at the level of the endometrium. This review discusses the intricacies of embryo implantation including the window of implantation, the cyclical phases of the endometrium, the implantation process itself, and features of endometrial receptivity. Additionally, we will discuss new research regarding inflammatory reproductive biology, epigenetics and microRNA, and the role of the vaginal and endometrial microbiome in implantation. A better understanding of embryo implantation and the interactions occurring at the level of the blastocyst and the endometrium will improve patient care for infertile patients who experience this frustrating challenge.

Pregnancy outcomes following different protocols of controlled ovarian hyperstimulation in couples undergoing intrauterine insemination

Clomiphene citrate (CC), letrozole and cetrorelix acetate are frequently used agents in controlled ovarian hyperstimulation (COH). However, these three agents have not yet been compared to one another regarding their pregnancy outcomes. The present study was designed to retrospectively compare pregnancy outcomes among the three aforementioned agents. This study involved infertile couples with an infertility duration of at least 2 years, ages 18 to 42 years and who were referred to have their first intrauterine insemination (IUI) treatment cycle. All patients underwent COH with recombinant follicle-stimulating hormone (rFSH) plus CC (n = 118), letrozole (n = 81), or cetrorelix acetate (n = 62), followed by IUI. Using the one-way multivariate analysis of covariance to control female patients' ages, patients stimulated with cetrorelix acetate/rFSH or CC/rFSH had higher numbers of preovulatory follicles than women stimulated with letrozole/rFSH (P < .02), whereas women stimulated with cetrorelix acetate/rFSH had a thicker endometrium than women stimulated with CC/rFSH (P < .0005). Biochemical pregnancy rates were similar among the three protocols of COH. However, women stimulated with letrozole/rFSH showed clinical pregnancy rates higher than those stimulated with CC/rFSH (P = .003) or cetrorelix acetate/rFSH (P = .03) and subclinical abortion rates lower than those stimulated with CC/rFSH or cetrorelix acetate/rFSH (P = .009). Of the different protocols of COH, the odds of having a clinical pregnancy was 3.1 times greater for women stimulated with letrozole/rFSH than women stimulated with CC/rFSH (P = .004) and 2.8 times greater for women stimulated with letrozole/rFSH than women stimulated with cetrorelix acetate/rFSH (P = .03). Our observations show that increased numbers of preovulatory follicles or endometrium thickness do not necessarily improve pregnancy outcomes, because pregnancy outcomes are also subjected to the type of COH used agent. In this regard, letrozole produced fewer preovulatory follicles and did not significantly increase endometrium thickness, but significantly improved pregnancy outcomes in comparison to CC and cetrorelix acetate.

Use of clomiphene citrate protocol for controlled ovarian stimulation impairs endometrial maturity

INTRODUCTION

Despite recent advances in assisted reproduction techniques and recent knowledge regarding embryo and endometrium quality, implantation and birth rates remain low. The objective of this study was to investigate whether clomiphene citrate alters endometrial maturation in infertile patients.

METHODS

In a prospective self-matched cohort study, we assessed the ovulation of women in spontaneous and stimulated cycles (with clomiphene citrate). We determined the ovulation day by ultrasound scanning. In both cycles, we took four blood samples (BS1 - at early proliferative phase, BS2 - at mid proliferative phase, BS3 - after ovulation and BS4 - at mid luteal phase) to determine the serum concentrations of FSH, LH, estradiol and progesterone. We retrieved an endometrial biopsy five days after ovulation, followed by blinded analysis and classification according to Noyes criteria, in both cycles.

RESULTS

Twenty-two participants completed the study. There were significant differences in FSH BS3 (p=0.001), in LH BS3 and BS4 (p<0.001 and p=0.049, respectively), in estradiol BS2, BS3 and BS4 (p<0.001, p=0.024 and p<0.001, respectively) and in progesterone BS3 and BS4 (p=0.028 and p<0.001, respectively). Considering Noyes criteria, there was a one-day delay when comparing the stimulated cycle with the spontaneous cycle (p=0.004), and a two-day delay when comparing the stimulated cycle with the biopsy day.

CONCLUSION

This study indicates that ovarian stimulation with clomiphene citrate delays the endometrial maturity, and could possibly impair the implantation process due to asynchrony.

Progesterone modulates adhesion molecules in uterine epithelial cells and in vitro embryo production in buffalo

This study was undertaken to evaluate the role of progesterone (P4) in modulation of the expression profile of adhesion-related molecules in uterine epithelial cells (UECs) and in vitro blastocyst production in buffalo. UECs were isolated from slaughterhouse-derived uteri by enzymatic treatment, and cells were characterized by immunocytochemistry (ICC) and PCR assays. The well-characterized UECs were exposed to different concentrations of P4 (0, 0.314, 3.14 and 6.28 ng/ml) along with the basal level of oestradiol for 6 days. Thereafter, the relative mRNA expression of different biomolecules such as mucin 1 (MUC1), osteopontin, integrin alpha (α3, α6 and αV) and beta (β1 and β3) subunits, progesterone receptor (PR) and oestrogen receptor, was evaluated. Further, day 2 post-insemination embryos were cultured in mSOF supplemented with or without P4. UECs were found positive for cytokeratin expression and negative for vimentin expression. Progesterone treatment significantly enhanced the mRNA expression of most of the transcripts compared with the control group, and correspondingly, the immunofluorescence depicted higher protein expression of all these molecules. Further, the long-term exposure of UECs to P4 downregulated the expression of PR and, concomitantly, MUC1. Progesterone supplementation to embryo culture medium significantly (p < .05) improved the blastocyst rate. The study demonstrates the role of P4 hormone in modulation of the expression of early implantation-related biomolecules in uterine epithelial cells; hence, adequate level of steroids is crucial for normal embryo development and its implantation.

Effects of clomiphene citrate plus estradiol or progesterone on endometrial ultrastructure: An RCT

Background

Pinopods concentrations in endometrial surface is a marker of implantation. Estradiol valerate (EV) was used to change the adverse effects of Clomiphene Citrate (CC) on the endometrium.

Objective

The goal was to assess whether there is a significant difference in the endometrial pinopods concentrations and other parameters after adding EV and progesterone to higher doses of CC.

Materials and Methods

In this prospective randomized clinical trial, a total of 30 women who did not respond to 100 mg of CC from February 2016 to June 2016 were evaluated. They were divided into three groups: group I) received 150 mg of CC alone, group II) CC with EV, and group III) CC plus progesterone. On day 21 of the menstrual cycle, endometrial biopsy, a blood sampling, and a scanning by electron microscopy were performed.

Results

On day 21 of the menstrual cycle, there was no significant difference in the pinopods concentrations (p = 0.641) and serum estrogen levels (p = 0.276) between groups. However, the Serum progesterone levels in group I was higher than the other two groups (p = 0.007) in the same day.

Conclusion

Since the addition of EV and progesterone to higher dosages of CC did not change the pinopods concentration and serum estrogen levels on day 21 of the menstrual cycle, and the serum progesterone levels was higher in CC alone group (i.e. group I) compared to other groups, it can be concluded that the anti-estrogenic effects of CC just appear on the endometrium and not on the plasma levels.

Autoimmune Regulator is required in female mice for optimal embryonic development and implantation†

Autoimmune Regulator (AIRE) regulates central immune tolerance by inducing expression of tissue-restricted antigens in thymic medullary epithelial cells, thereby ensuring elimination of autoreactive T cells. Aire mutations in humans and targeted Aire deletion in mice result in multiorgan autoimmune disease, known in humans as autoimmune polyglandular syndrome type 1 (APS-1). APS-1 is characterized by the presence of adrenal insufficiency, chronic mucosal candidiasis, and/or hypoparathyroidism. Additionally, females often present with gonadal insufficiency and infertility. Aire-deficiency (KO) in mice results in oophoritis and age-dependent depletion of follicular reserves. Here, we found that while the majority of young 6-week-old Aire-KO females had normal follicular reserves, mating behavior, and ovulation rates, 50% of females experienced embryonic loss between gestation day (GD) 5.5 and 7.5 that could not be attributed to insufficient progesterone production or decidualization. The quality of GD0.5 embryos recovered from Aire KO mice was reduced, and when cultured in vitro, embryos displayed limited developmental capacity in comparison to those recovered from wild-type (WT) mice. Further, embryos flushed from Aire KO dams at GD3.5 were developmentally delayed in comparison to WT controls and had reduced trophoblastic outgrowth in vitro. We conclude that AIRE does not play a direct role in uterine decidualization. Rather, reduced fertility of Aire-deficient females is likely due to multiple factors, including oophoritis, delayed preimplantation development, and compromised implantation. These effects may be explained by autoimmune targeting of the ovary, embryo, or both. Alternatively, altered embryonic development could be due to a direct role for AIRE in early embryogenesis.

GRASP depletion-mediated Golgi destruction decreases cell adhesion and migration via the reduction of α5β1 integrin

The Golgi apparatus is a membrane-bound organelle that serves as the center for trafficking and processing of proteins and lipids. To perform these functions, the Golgi forms a multilayer stacked structure held by GRASP55 and GRASP65 trans-oligomers and perhaps their binding partners. Depletion of GRASP proteins disrupts Golgi stack formation and impairs critical functions of the Golgi, such as accurate protein glycosylation and sorting. However, how Golgi destruction affects other cellular activities is so far unknown. Here, we report that depletion of GRASP proteins reduces cell attachment and migration. Interestingly, GRASP depletion reduces the protein level of α5β1 integrin, the major cell adhesion molecule at the surface of HeLa and MDA-MB-231 cells, due to decreased integrin protein synthesis. GRASP depletion also increases cell growth and total protein synthesis. These new findings enrich our understanding on the role of the Golgi in cell physiology and provide a potential target for treating protein-trafficking disorders.

Neonatal outcomes following different ovarian stimulation protocols in fresh single embryo transfer

Previous studies suggested ovarian stimulation was associated with lower birth weight and higher risk of preterm delivery (PTD) from fresh embryo transfers (ETs). However, whether the increased risk differs between distinct ovarian stimulation protocols remains unknown. A retrospective cohort study of 38,220 singleton deliveries after fresh single ETs from 2007 to 2013 was conducted. Main outcomes were birth weight and gestational length. Compared with the natural cycle, all ovarian stimulation protocols were associated with a significantly increased risk for PTD, low birth weight (LBW) and small for gestational age (SGA). In subgroup analysis of maternal age under 35 years, luteal support using progesterone, and early cleavage ETs, the significant associations remained for LBW and SGA in gonadotropin-releasing hormone (GnRH) antagonist protocol and for LBW in GnRH agonist protocol. Ovarian stimulation using clomiphene citrate (CC) had the highest increased risks for LBW (Adjusted odds ratio [AOR], 1.58, 95% confidence interval [95% CI], 1.43-1.73) and SGA (AOR, 1.65, 95% CI, 1.50-1.82) compared with natural cycles, and was further associated with PTD and cesarean section. These findings suggest ovarian stimulation was associated with lower birth weight, and CC may have adverse effect on neonatal outcomes in fresh cycles.

Effect of follicular diameter at the time of ovulation triggering on pregnancy outcomes during intrauterine insemination

OBJECTIVE

To compare pregnancy outcomes when triggering ovulation at different follicle sizes during intrauterine insemination (IUI) cycles.

METHODS

A prospective observational study was undertaken at two collaborative fertility centers in Saudi Arabia between January 2014 and May 2016. Women of any age were enrolled if they met inclusion criteria: primary, secondary, or unexplained infertility (≥1 year); day-2 follicle-stimulating hormone less than 12 IU/mL; normal prolactin, thyroid function, and uterine cavity; at least one patent tube; and a male partner with normal semen count and motility. IUI cycles were subdivided by size of dominant follicle (17 to <18 mm, 18 to <19 mm, 19 to <20 mm, and ≥20 mm), and pregnancy outcomes compared.

RESULTS

Data from 516 IUI cycles were analyzed. Frequencies of clinical pregnancy, ongoing pregnancy, and live birth for a follicle size of 19-20 mm were 30.2% (39/129), 24.0% (31/129), and 24.0% (31/129), respectively; these rates were significantly higher than those in other groups (all P<0.05). Only endometrial thickness was found to also contribute to outcome: probability of pregnancy increased as thickness rose (odds ratio 1.148, 95% confidence interval 1.065-1.237; P<0.001).

CONCLUSION

The optimal follicular diameter associated with increased pregnancy rates in gonadotropin-stimulated IUI cycles was between 19 and 20 mm.

Progesterone luteal support after ovulation induction and intrauterine insemination: an updated systematic review and meta-analysis

OBJECTIVE

To evaluate the effect of progesterone (P) for luteal phase support after ovulation induction (OI) and intrauterine insemination (IUI).

DESIGN

An updated systematic review and meta-analysis.

SETTING

Not applicable.

PATIENT(S)

Patients undergoing OI-IUI for infertility.

INTERVENTION(S)

Exogenous P luteal support after OI-IUI.

MAIN OUTCOME MEASURE(S)

Live birth.

RESULT(S)

Eleven trials were identified that met inclusion criteria and constituted 2,842 patients undergoing 4,065 cycles, more than doubling the sample size from the previous meta-analysis. In patients receiving gonadotropins for OI, clinical pregnancy (relative risk [RR] 1.56, 95% confidence interval [CI] 1.21-2.02) and live birth (RR 1.77, 95% CI 1.30-2.42) were more likely in P supplemented patients. These findings persisted in analysis of live birth per IUI cycle (RR 1.59, 95% CI 1.24-2.04). There were no data on live birth in clomiphene citrate or clomiphene plus gonadotropin cycles. There was no benefit on clinical pregnancy with P support for patients who underwent OI with clomiphene (RR 0.85, 95% CI 0.52-1.41) or clomiphene plus gonadotropins (RR 1.26, 95% CI 0.90-1.76).

CONCLUSION(S)

Progesterone luteal phase support is beneficial to patients undergoing ovulation induction with gonadotropins in IUI cycles. The number needed to treat is 11 patients to have one additional live birth. Progesterone support did not benefit patients undergoing ovulation induction with clomiphene citrate or clomiphene plus gonadotropins.

Treatment Strategies for the Infertile Polycystic Ovary Syndrome Patient

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of reproductive age. Infertility is a prevalent presenting feature of PCOS, and approximately 75% of these women suffer infertility due to anovulation. Lifestyle modification is considered the first-line treatment and is associated with improved endocrine profile. Clomiphene citrate (CC) should be considered as the first line pharmacologic therapy for ovulation induction. In women who are CC resistant, second-line treatment should be considered, as adding metformin, laparoscopic ovarian drilling or treatment with gonadotropins. In CC treatment failure, Letrozole could be an alternative or treatment with gonadotropins. IVF is considered the third-line treatment; the ‘short’, antagonist-based protocol is the preferred option for PCOS patients, as it is associated with lower risk of developing ovarian hyperstimulation syndrome (specifically by using a gonadotropin-releasing hormone agonist as ovulation trigger), but with comparable outcomes as the long protocol.

Deletion of Lysophosphatidic Acid Receptor 3 (Lpar3) Disrupts Fine Local Balance of Progesterone and Estrogen Signaling in Mouse Uterus During Implantation

Lpar3 encodes LPA3, the third G protein-coupled receptor for lysophosphatidic acid (LPA). Lpar3(-/-) female mice had delayed embryo implantation. Their serum progesterone and estrogen levels were comparable with control on Gestation Day 3.5 (D3.5) at 1100 h. There was reduced cell proliferation in D3.5 and D4.5 Lpar3(-/-) stroma. Progesterone receptor (PGR) disappeared from D4.5 Lpar3(+/+) uterine luminal epithelium (LE) but remained highly expressed in D4.5 Lpar3(-/-) LE. Pgr and PGR- target genes but not estrogen receptor alpha (ERalpha [Esr1]) or ESR target genes, were upregulated in D4.5 Lpar3(-/-) LE. It was hypothesized that suppression of PGR activity in LE could restore on-time uterine receptivity in Lpar3(-/-) mice. A low dose of RU486 (5 μg/mouse) given on D3.5 at 900 h rescued delayed implantation in all pregnant Lpar3(-/-) females and significantly increased number of implantation sites compared to vehicle-treated pregnant Lpar3(-/-) females detected on D4.5. E2 (25 ng/mouse) had a similar effect as 5 μg RU486 on embryo implantation in Lpar3(-/-) females. However, when the ovaries were removed on late D2.5 to create an experimentally induced delayed implantation model, 25 ng E2 activated implantation in Lpar3(+/+) but not Lpar3(-/-) females detected on D4.5. These results demonstrate that deletion of Lpar3 leads to an increased ratio of progesterone signaling/estrogen signaling that can be optimized by low doses of RU486 or E2 to restore on-time implantation in Lpar3(-/-) females.

Ovarian stimulation by exogenous gonadotropin decreases the implantation rate and expression of mouse blastocysts integrins

BACKGROUND

Integrins are heterodimeric glycoprotein receptors that regulate the interaction of cells with extracellular matrix and may have a critical role in implantation. The aim of this study was to investigate the effect of ovulation induction on the expression of α4, αv, β1, and β3 integrins in mouse blastocyst at the time of implantation.

METHODS

The ovarian stimulated and non-stimulated pregnant mice were sacrificed on the morning of 5th day of pregnancy. The blastocysts were collected, and the expression of αv, α4, β1, and β3 integrins was examined using real-time RT-PCR and immunocytochemical techniques, then their ovarian hormones were analyzed at the same time. The implantation sites in uterine horns of other pregnant mice in both groups were determined under a stereomicroscope on the 7th day of pregnancy.

RESULTS

The results showed that the expression of αv, β1, and β3 integrins in both mRNA and protein levels was significantly lower in the ovarian stimulated group than the control group, and the maximum ratio of expression was belonged to β1 molecule (P>0.05).

CONCLUSION

The implantation rate in superovulated mice was significantly lower than control mice. It was suggested that ovulation induction decreased the expression of αv, β1, and β3 integrins of mouse blastocysts.

NILCO biomarkers in breast cancer from Chinese patients

BACKGROUND

Notch, IL-1 and leptin are known pro-angiogenic factors linked to breast cancer development, tumor aggressiveness and poor prognosis. A complex crosstalk between these molecules (NILCO) has been reported in breast cancer cell lines. However, whether NILCO biomarkers are differentially expressed in estrogen responsive (ER+), unresponsive (ER-) and triple negative (TNBC) breast cancer tissues is unknown.

METHODS

Expression levels of nine NILCO and targets [Notch1, Notch4, JAG1, DLL4, VEGF, VEGFR2 (FLK-1), leptin, leptin receptor (OB-R) and interleukin-1 receptor type I (IL-1R tI)] were examined via immunohistochemistry in breast cancer tissue microarrays from Chinese patients (ER+, n=33; ER-, n=21; TNBC, n=13) and non-malignant breast tissue (n=5; Pantomics, Inc.) using a semi-quantitative analysis of intensity staining, HSCORE.

RESULTS

Categorical expression of NILCO and targets (+ or -) was similar among all cancer tissues. However, TNBC showed differential localization pattern of NILCO. TNBC showed fewer nuclei and cytoplasms positive for Notch4 and JAG1, but more cytoplasms positive for leptin. In addition, fewer TNBC stromas were positive for Notch1 and Notch4, but 100% of TNBC stromas were positive for VEGFR2. Moreover, TNBC had lower DLL4 and IL-1R tI expression. TNBC and ER- showed higher expression of EGFR, but lower expression of AR. Leptin and OB-R were detected in more than 61% of samples. Leptin positively correlated to OB-R, JAG1, VEGF, and marginally to IL-1R tI. Notch1 positively correlated to IL-1R tI. EGFR and Ki67 were positively associated to Notch1, but no associations of NILCO and targets with p53 were found.

CONCLUSIONS

Present data suggest that NILCO components are differentially expressed in breast cancer. TNBC showed distinctive patterns for NILCO expression and localization. The complex crosstalk between leptin, IL-1 and Notch could differentially drive breast cancer growth and angiogenesis. Furthermore, the analysis of NILCO and targets using Pathway Studio9 software (Ariadine Genomics) showed multiple molecular relationships that suggest NILCO has potential prognostic biomarker value in breast cancer.

Does optimal follicular size in IUI cycles vary between clomiphene citrate and gonadotrophins treatments?

OBJECTIVE

To evaluate pregnancy-related leading follicles during ovulation induction and superovulation with clomiphene citrate (CC) or gonadotropin.

DESIGN

Retrospective cohort.

PATIENTS

Five hundred and forty-two women who underwent a total of 615 treatment cycles with CC or gonadotropin.

INTERVENTION

We evaluated the effects of CC and gonadotropin on the leading follicles, clinical pregnancy rates and miscarriage rate.

RESULTS

The number of follicles larger than 15 mm in the different protocols was comparable. In those treated with CC, the diameter of the dominant follicles before human chorionic gonadotropins (hCG) trigger in the conception cycles (20.4 ± 1.2 mm) was significantly larger than in the non-conception cycles (18.8 ± 1.9 mm). In women treated with gonadotropin, the diameter of the leading follicle in the conception cycles (18.5 ± 1.7 mm) was comparable to that in the non-conception cycles (18.2 ± 1.7 mm). The pregnancy-related diameter of the leading follicle in CC cycles (20.4 ± 1.2 mm) was significantly larger than that in gonadotropin cycles (18.8 ± 1.9 mm; p = 0.001; 95% CI, -2.2 to -0.9).

CONCLUSION

Pregnancy-related diameter of the leading follicle in CC cycles is significantly larger than that in gonadotropin cycles and the best time for hCG trigger in the CC cycle is when the leading follicle reaches 20 mm.

Endometrial receptivity markers in infertile women stimulated with letrozole compared with clomiphene citrate and natural cycles

Though various advantages associated with the use of letrozole as an ovulation inducing drug are documented, there is inadequate information regarding its effect on endometrial receptivity. Expression of endometrial receptivity markers including αvβ3 integrin, L-selectin, LIF, and pinopods during the implantation window in infertile women stimulated with letrozole or clomiphene citrate (CC), and spontaneous cycles is investigated. A total of 36 women were included in the study out of which 16 women were diagnosed with primary unexplained infertility and the other 20 women with severe oligoasthenozoospermic/azoospermic male partners. Both groups were sub-divided into three groups; women stimulated with letrozole, or with CC, and the third group was allowed to ovulate spontaneously (natural cycles). Women having natural cycles and not given any drug were considered as controls. Once ovulation was confirmed by ultrasonography, endometrial samples were collected on the seventh day post-ovulation and analyzed. In women with unexplained infertility treated with letrozole and CC, epithelial and stromal expression of αvβ3 integrin, L-selectin, leukemia inhibitory factor (LIF), and pinopod formation was found to be significantly higher as compared to controls. Expression of these receptivity markers was found to be comparable amongst the letrozole, CC, and control groups in women with severe oligoasthenozoospermic/azoospermic male partners. Cell cycle analysis showed similar cell cycle phase fractions on comparing the CC and the letrozole groups. Stimulation with letrozole and CC appears to enhance endometrial receptivity in women with unexplained infertility. However, letrozole and CC did not have any significant effect on the endometrial receptivity markers of women with severe oligoasthenozoospermic/azoospermic male partners.

Combined analysis of microRNome and 3'-UTRome reveals a species-specific regulation of progesterone receptor expression in the endometrium of rhesus monkey

The establishment of endometrial receptivity is a prerequisite for successful pregnancy, which is controlled by a complex mechanism. MicroRNAs (miRNAs) are small non-coding RNAs that have emerged as important regulators of gene expression. However, the contribution of miRNAs in endometrial receptivity is still unknown. Here we used rhesus monkey as an animal model and compared the endometrial miRNA expression profiles during early-secretory (pre-receptive) phase and mid-secretory (receptive) phase by deep sequencing. A set of differentially expressed miRNAs were identified, 8 of which were selected and validated using quantitative RT-PCR. To facilitate the prediction of their target genes, the 3'-UTRome was also determined using tag sequencing of mRNA 3'-termini. Surprisingly, about 50% of the 10,677 genes expressed in the rhesus monkey endometrium exhibited alternative 3'-UTRs. Of special interest, the progesterone receptor (PGR) gene, which is necessary for endometrial receptivity, processes an ultra long 3'-UTR (~10 kb) along with a short variant (~2.5 kb). Evolutionary analysis showed that the 3'-UTR sequences of PGR are poorly conserved between primates and rodents, suggesting a species-biased miRNA binding pattern. We further demonstrated that PGR is a valid target of miR-96 in rhesus monkey and human but not in rodents, whereas the regulation of PGR by miR-375 is rhesus monkey-specific. Additionally, we found that miR-219-5p regulates PGR expression through a primate-specific long non-coding RNA immediately downstream of the PGR locus. Our study provides new insights into the molecular mechanisms underlying endometrial receptivity and presents intriguing species-specific regulatory roles of miRNAs.

Preimplantation exposure to bisphenol A (BPA) affects embryo transport, preimplantation embryo development, and uterine receptivity in mice

To investigate the effects of bisphenol A (BPA) on embryo and uterine factors in embryo implantation, timed pregnant C57BL6 females were treated subcutaneously with 0, 0.025, 0.5, 10, 40, and 100mg/kg/day BPA from gestation days 0.5-3.5. In 100mg/kg/day BPA-treated females, no implantation sites were detected on day 4.5 but retention of embryos in the oviduct and delayed embryo development were detected on day 3.5. When untreated healthy embryos were transferred to pseudopregnant females treated with 100mg/kg/day BPA, no implantation sites were detected on day 4.5. In 40 mg/kg/day BPA-treated females, delayed implantation and increased perinatal lethality of their offspring were observed. Implantation seemed normal in the rest BPA-treated groups or the female offspring from 40 mg/kg/day BPA-treated group. These data demonstrate the adverse effects of high doses of BPA on processes critical for embryo implantation: embryo transport, preimplantation embryo development, and establishment of uterine receptivity.

Progesterone resistance in PCOS endometrium: a microarray analysis in clomiphene citrate-treated and artificial menstrual cycles

CONTEXT

Polycystic ovary syndrome (PCOS), the most common endocrinopathy of reproductive-aged women, is characterized by ovulatory dysfunction and hyperandrogenism.

OBJECTIVE

The aim was to compare gene expression between endometrial samples of normal fertile controls and women with PCOS.

DESIGN AND SETTING

We conducted a case control study at university teaching hospitals.

PATIENTS

Normal fertile controls and women with PCOS participated in the study.

INTERVENTIONS

Endometrial samples were obtained from normal fertile controls and from women with PCOS, either induced to ovulate with clomiphene citrate or from a modeled secretory phase using daily administration of progesterone.

MAIN OUTCOME MEASURE

Total RNA was isolated from samples and processed for array hybridization with Affymetrix HG U133 Plus 2 arrays. Data were analyzed using GeneSpring GX11 and Ingenuity Pathways Analysis. Selected gene expression differences were validated using RT-PCR and/or immunohistochemistry in separately obtained PCOS and normal endometrium.

RESULTS

ANOVA analysis revealed 5160 significantly different genes among the three conditions. Of these, 466 were differentially regulated between fertile controls and PCOS. Progesterone-regulated genes, including mitogen-inducible gene 6 (MIG6), leukemia inhibitory factor (LIF), GRB2-associated binding protein 1 (GAB1), S100P, and claudin-4 were significantly lower in PCOS endometrium; whereas cell proliferation genes, such as Anillin and cyclin B1, were up-regulated.

CONCLUSIONS

Differences in gene expression provide evidence of progesterone resistance in midsecretory PCOS endometrium, independent of clomiphene citrate and corresponding to the observed phenotypes of hyperplasia, cancer, and poor reproductive outcomes in this group of women.

Report of the international symposium: polycystic ovary syndrome: first Latin-American consensus

During the last years, numerous consensuses have been held in different countries in order to review the data concerning diagnosis and treatment and their relationship with the ethnic origin, social status and lifestyle of women with Polycystic Ovary Syndrome (PCOS). This study describes the conclusions concerning diagnostic criteria and the appropriate treatment of women with PCOS reached during the International Symposium Polycystic Ovary Syndrome, First Latin-American Consensus held in Buenos Aires, Argentina on 4th and 5th May 2009 to be applied in South American.

Unique uterine localization and regulation may differentiate LPA3 from other lysophospholipid receptors for its role in embryo implantation

OBJECTIVE

To determine factors differentiating LPA3 from other lysophospholipid (LP) receptors for its role in embryo implantation.

DESIGN

Experimental mouse models.

SETTING

Institute/university research laboratories.

ANIMAL(S)

Wild-type, Lpar3(-/-), Lpar1(-/-)Lpar2(-/-), and S1pr2(-/-)S1pr3(-/-) mice.

INTERVENTION(S)

Ovariectomy.

MAIN OUTCOME MEASURE(S)

Blue dye injection for determining implantation sites on gestation day 4.5. Real-time polymerase chain reaction for measuring gene expression in whole uterus and separated uterine layers. In situ hybridization for detecting progesterone (P)-induced Lpar3 expression in the uterine luminal epithelium (LE).

RESULT(S)

Normal implantation was observed in Lpar1(-/-)Lpar2(-/-) and S1pr2(-/-)S1pr3(-/-) females. Temporal expression showed peak expression of Lpar3 in the preimplantation uterus and constitutive expression of the other nine LP receptors in the periimplantation uterus. Spatial localization revealed main expression of Lpar3 in the LE and broad expression of the remaining LP receptors in all three main uterine layers: LE, stromal, and myometrial layers. Hormonal regulation in ovariectomized uterus indicated up-regulation of Lpar3 but down-regulation or no effect of the remaining nine LP receptors by P, and down-regulation of most LP receptors, including Lpar3, by 17β-estradiol.

CONCLUSION(S)

LE localization and up-regulation by P differentiate LPA3 from the other nine LP receptors and may underlie its essential role in embryo implantation.

Temporal expression pattern of progesterone receptor in the uterine luminal epithelium suggests its requirement during early events of implantation

OBJECTIVE

To determine the precise timing of progesterone receptor (PR) disappearing from the uterine luminal epithelium (LE) to help understand the significance of the dynamic PR expression in the LE during embryo implantation.

DESIGN

Experimental rodent models.

SETTING

University research laboratories.

ANIMAL(S)

Mice and hamsters.

INTERVENTION(S)

Pseudopregnancy and artificial decidualization.

MAIN OUTCOME MEASURE(S)

Blue dye injection for detecting embryo attachment; immunohistochemistry, immunofluorescence, and in situ hybridization for detecting gene expression.

RESULT(S)

Progesterone receptor remained expressed in the LE up to 6 hours after the initial detection of blue dye reaction in mice (day 3, 22:00 hours), but disappeared first from LE cells at the implantation site and subsequently from the entire LE layer by day 4, 06:00 hours, when uterine stromal decidualization had become obvious. Progesterone receptor remained highly expressed in the LE of day 4 at 11:00 hours in pseudopregnant mice, but it disappeared from the entire LE layer by day 4 at 06:00 hours in artificially decidualized pseudopregnant mice.

CONCLUSION(S)

Progesterone receptor disappears from the LE after implantation has initiated and before the histologic decidualization manifests, suggesting an active role of continued PR expression in the LE for the initial implantation process. The disappearance of PR expression in the LE is regulated by uterine factor(s) produced upon embryo attachment.

Expression of alphaVbeta3 integrin in rat endometrial epithelial cells and its functional role during implantation

The alpha(V)beta(3) integrin as a marker of endometrial receptivity has been well established in human and other mammalian species; however, its expression is still not known in rats. Our objective was to establish the expression of alpha(V)beta(3) integrin as a marker of endometrial receptivity in rat and to further prove its role in implantation by function-blocking studies in this species. Immunocytochemical, immunohistochemical and flow-cytometric studies were performed in rat endometrial epithelial cells (EEC) to demonstrate the expression of alpha(V)beta(3) integrin during non-receptive, pre-receptive and receptive phases of the uterus. Results revealed positive immunocytochemical staining for alpha(v) and beta(3) subunits on the surface of EEC of days 4 and 5p.c. (post-coitum), but the intensity was higher in cells of day 5p.c. Flow-cytometric study revealed higher level of alpha(V)beta(3) on day 5p.c. as compared to day 4p.c. and non-pregnant animals. Immunohistochemical analysis of uterine tissue also revealed that the alpha(V)beta(3) expression in LE was higher on day 5p.c. morning as compared to that observed on day 4p.c. In addition, the expression of beta(3) subunit was not evident in rats receiving ormeloxifene, an agent known to inhibit the uterine receptivity. Immunoblotting experiments also revealed higher expression of uterine beta(3) on day 5p.c. On day 6, expression of beta(3) was high in implantation sites than on inter-implantation sites. In immature ovariectomized rats, alpha(V)beta(3) was up-regulated by progesterone and by a combination of estrogen and progesterone. The expression of alpha(V)beta(3) was also up-regulated in EEC co-cultured with blastocysts. All the agents used for function-blocking studies showed significant reduction in the number of implantation sites in treated horn as compared to sham control horn. The present study has successfully demonstrated the expression of alpha(V)beta(3) in rat EEC as a marker of endometrial receptivity and showed that this molecule is indispensable for the process of implantation in this species.

Osteopontin and alphavbeta3 integrin expression in the endometrium of infertile and fertile women

Osteopontin and its receptor alpha(v)beta(3) integrin have recently been proposed as a major complex to promote embryo attachment, and thus they would be useful as markers of endometrial receptivity. In the current study alpha(v)beta(3) integrin and osteopontin expression and co-expression in in-phase and out-of-phase endometrial biopsies from normal healthy women (n = 12) and infertile patients (n = 107) were investigated. Two endometrial biopsies (post-ovulatory day +6 to +8, and 4 days later) were performed during a single menstrual cycle in each subject. Oestradiol and progesterone serum concentrations were quantified on the same days as endometrial sampling. No statistically significant difference regarding alpha(v)beta(3) integrin and osteopontin expression and their coexpression was found between fertile controls and infertile patients irrespective of endometria being in-phase or out-of-phase, infertility factors detected or whether patients became spontaneously pregnant or not. Although a co-ordinate high concentration of both glycoproteins on post-ovulatory day 8 onwards was observed, there was an evident lack of temporal co-expression of these markers during the implantation window. It is concluded that the functional significance of the osteopontin:alpha(v)beta(3) integrin complex as a marker of endometrial receptivity and implantation potential in women seems to be untenable.

Effects of ovarian stimulation on endometrial integrin β3 and leukemia inhibitory factor expression in the peri-implantation phase

OBJECTIVE

To investigate the effects of ovarian stimulation on endometrial receptivity in the peri-implantation phase.

DESIGN

Comparison of integrin beta3 and leukemia inhibitory factor (LIF) expression in endometrial biopsies from moderate responders and high responders with temporally matched natural cycles.

SETTING

Clinical and experimental research.

PATIENT(S)

Patients with cancelled embryo transfer were evaluated. Moderate responders were defined as E2 5,000-15,000 pmol/L on the day of hCG administration (group B, n = 7). High responders were defined as E2 >15,000 pmol/L on the day of hCG administration (group C, n = 8). Healthy and fertile volunteers were used as natural controls (group A, n = 10).

INTERVENTION(S)

Endometrial biopsy on the day of LH+7/hCG+7.

MAIN OUTCOME MEASURE(S)

Immunohistochemistry of integrin beta3 and LIF and imaging analysis.

RESULT(S)

Endometrial integrin beta3 and LIF expressions in the peri-implantation phase were significantly lower in stimulated cycles (including both moderate and high responders) compared to natural controls. Expression of LIF in glandular epithelium in high responders was lower than that in moderate responders.

CONCLUSION(S)

These data demonstrated that suggested markers of endometrial receptivity were reduced in stimulated cycles compared with natural cycles, and more so in high response cycles compared with moderate response cycles.

Mild stimulation with clomiphene citrate in combination with recombinant follicle-stimulating hormone and gonadotropin-releasing hormone antagonist and its influence on serum estradiol level and pregnancy rate

Aim:  The mild ovarian stimulation protocol for in vitro fertilization (IVF) is carried out to minimize adverse side-effects as well as cost. While performing mild ovarian stimulation with a gonadotropin-releasing hormone (GnRH) antagonist, the pregnancy rate was examined in cases that exhibited a serum estradiol (E2) drop down. Methods:  In this study, 174 patients who requested mild ovarian stimulation for IVF began clomiphene citrate on day 3 and recombinant follicle-stimulating hormone (FSH) on day 5 of their menstrual cycles. A GnRH antagonist was administered when the dominant follicle reached a diameter of 14 mm. Serum luteinizing hormone and estradiol were measured at the time of GnRH antagonist administration and at the time of human chorionic gonadotropin (hCG) injection. Pregnancy rates and implantation rates were compared between 24 cycles in which the E2 level fell at the time of hCG injection and 150 cycles in which it did not fall. Results:  The pregnancy rate in the cases in which the E2 level fell (25% decrease) at the time of hCG injection was significantly lower than it was in the cases in which it did not fall (16.7 vs 41.0%). The implantation rate for the cases in which the E2 level fell was also lower than that of the control group (7.0 vs 31.0%). There was no significant difference in the number of good-quality embryos between the two groups. Conclusion:  When performing the mild ovarian stimulation protocol, serum E2 should be followed. It is prudent to avoid embryo transfer in the same cycle in cases that exhibit E2 drop down. (Reprod Med Biol 2008; 7: 85-89).

The human endometrium as a fertility-determining factor

Intensive research work has been performed to better understand the regulation of the endometrium and its clinical implications to improve implantation. Although many proteins and molecules may influence endometrial development, their co-ordinated contribution to the implantation process is still poorly understood and a translation into clinical use has not sufficiently been performed. Clinical evaluation of the endometrium by ultrasound and other techniques, like endometrial biopsy and analysis of uterine secretions, has been intensively studied and therapeutic options to improve endometrial function have been suggested and tested. Systemic treatment with heparin, aspirin or corticosteroids did not result in improved implantation rates. Gene therapy and cervical treatment, e.g. with seminal plasma, are still in the phase of clinical research. Therefore, this review focuses on different aspects of endometrial research, which all contribute to the diagnosis, evaluation and therapy of endometrial function and dysfunction. First, the endometrial development towards a receptive milieu is described. Second, the actual clinical evaluation of endometrial receptivity, possible therapeutic strategies and in particular, the evaluation of endometrial function in the non-natural situation of hormonal stimulation is critically evaluated. In conclusion, the endometrium shall be considered as an important fertility-determining factor and therapeutic options should be developed in near future.

Evaluation of steroid receptors, coregulators, and molecules associated with uterine receptivity in secretory endometria from untreated women with polycystic ovary syndrome

OBJECTIVE

To evaluate gene and protein expression of steroid receptors, nuclear receptor coregulators, and uterine receptivity markers in midsecretory phase endometria from untreated women with polycystic ovary syndrome (PCOS).

DESIGN

Case-control study.

SETTING

Hospital research unit.

PATIENT(S)

Eight patients with PCOS and eight fertile women of similar age to those with PCOS.

INTERVENTION(S)

Endometrial samples were obtained from women with PCOS (PCOSE) and normal (NE) women during the midsecretory phase of the menstrual cycle.

MAIN OUTCOME MEASURE(S)

Expression studies (immunohistochemistry, reverse transcription-polymerase chain reaction [RT-PCR] and Western blot).

RESULT(S)

Endometria from PCOS exhibit higher levels of messenger RNA (mRNA) and protein for estrogen receptor alpha and coactivators than NE. Epithelial cells had a greater expression of progesterone receptor in PCOSE, whereas, no differences were observed in gene and protein expression of the nuclear corepressor (NcoR) and the antiadhesion molecule mucin type-1 (MUC-1) between PCOSE and NE. Immunodetection for the coactivator ARA70 was higher in PCOSE than in NE; in contrast, expression of beta3-integrin in epithelia was lower in PCOSE than in control endometria.

CONCLUSION(S)

The higher response to steroid hormones of endometria from untreated PCOS-women induces diminished expression of beta3 integrin, which partially explain implantation failure in PCOS patients.

Endometrial receptivity: Clinical assessment in relation to fertility, infertility, and antifertility

Fertility in humans and other mammalian species depends absolutely on synchronous events that render the developing blastocyst and the receiving uterus competent for implantation. Endometrial receptivity is defined as the period during which the endometrial epithelium acquires functional, but transient, ovarian steroid-dependent status supportive to blastocyst acceptance and implantation. Once inside the uterus, the blastocyst is surrounded by an intact luminal epithelium, which is considered to act as barrier to its attachment, except for this short period of high endometrial receptivity to blastocyst signal(s). Its transport and permeability properties, in conjunction with cellular action of the endometrium and the embryo, have been suggested to influence creation and maintenance of informational and nutritional status of uterine luminal milieu. This period, also termed as the 'window of implantation,' is limited to days 20-24 of menstrual cycle in humans. However, establishment of endometrial receptivity is still a biological mystery that remains unsolved despite marked advances in our understanding of endometrial physiology following extensive research associated with its development and function. This review deals with various structural, biochemical, and molecular events in the endometrium coordinated within the implantation window that constitute essential elements in the repertoire that signifies endometrial receptivity and is aimed to achieve a better understanding of its relationship to fertility, infertility, and for the development of targeted antifertility agents for human use and welfare.