Endometrial signaling pathways during ovarian stimulation for assisted reproduction technology

Spatial Transcriptomics analysis of uterine gene expression in enhancer of Zeste homolog 2 (Ezh2) conditional knockout mice

Histone proteins undergo various modifications that alter chromatin structure, including addition of methyl groups. Enhancer of homolog 2 (EZH2), is a histone methyltransferase that methylates lysine residue 27, and thereby, suppresses gene expression. EZH2 plays integral role in the uterus and other reproductive organs. We have previously shown that conditional deletion of uterine EZH2 results in increased proliferation of luminal and glandular epithelial cells, and RNAseq analyses reveal several uterine transcriptomic changes in Ezh2 conditional (c) knockout (KO) mice that can affect estrogen signaling pathways. To pinpoint the origin of such gene expression changes, we used the recently developed spatial transcriptomics (ST) method with the hypotheses that Ezh2cKO mice would predominantly demonstrate changes in epithelial cells and/or ablation of this gene would disrupt normal epithelial/stromal gene expression patterns. Uteri were collected from ovariectomized adult WT and Ezh2cKO mice and analyzed by ST. Asb4, Cxcl14, Dio2, and Igfbp5 were increased, Sult1d1, Mt3, and Lcn2 were reduced in Ezh2cKO uterine epithelium vs. WT epithelium. For Ezh2cKO uterine stroma, differentially expressed key hub genes included Cald1, Fbln1, Myh11, Acta2, and Tagln. Conditional loss of uterine Ezh2 also appears to shift the balance of gene expression profiles in epithelial vs. stromal tissue toward uterine epithelial cell and gland development and proliferation, consistent with uterine gland hyperplasia in these mice. Current findings provide further insight into how EZH2 may selectively affect uterine epithelial and stromal compartments. Additionally, these transcriptome data might provide the mechanistic understanding and valuable biomarkers for human endometrial disorders with epigenetic underpinnings.

Changes in thyroid function during controlled ovarian hyperstimulation (COH) and its impact on assisted reproduction technology (ART) outcomes: a systematic review and meta-analysis

BACKGROUND

To investigate the thyroid function changes during controlled ovarian hyperstimulation (COH) and ascertain its impact on reproductive outcomes.

METHODS

We conducted meta-analysis in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A comprehensive literature search was performed to identify studies reported changes in thyroid parameters during COH. We analyzed thyroid-stimulating hormone (TSH) levels, free thyroxin (fT4) levels, changes in estrogens (E2), thyroxine-binding globulin (TBG), relative risks (RRs) of clinical pregnancy rate (CPR), live birth rate (LBR), and mean difference (MD) of TSH increment between the miscarriage group and ongoing pregnancy group.

RESULTS

This meta-analysis included fifteen individual studies (n = 1665 subjects). At the end of COH, the mean TSH (2.53 mIU/L; 95% CI, 2.19 to 2.88; I² = 92.9%) exceeded the upper limit (2.5 mIU/L) and remained above the threshold until one month following embryo transfer (ET). Thyroxin decreased from baseline to the end of COH (-0.18 ng/l; 95% CI, -0.35 to 0.00; I² = 92.2%). The CPR and LBR of patients with TSH exceeding the cutoff after COH were significantly lower than those of patients with TSH below the threshold (CPR: RR, 0.62; 95% CI, 0.47 to 0.82; I² = 0.0% and LBR: RR, 0.64; 95% CI, 0.44 to 0.92; I² = 0.0%). The MD of the increment in TSH levels between the miscarriage and ongoing pregnancy groups was 0.40 mIU/L (95% CI, 0.15 to 0.65; I² = 0.0%).

CONCLUSIONS

This meta-analysis shows that TSH increases and fT4 decreases during COH. COH-induced thyroid disorder impairs reproductive outcomes.

Expression of genes that regulate follicle development and maturation during ovarian stimulation in poor responders

RESEARCH QUESTION

Sex hormone-binding globulin (SHBG), androgen receptor (AR), LH beta polypeptide (LHB), progesterone receptor membrane component 1 (PGRMC1) and progesterone receptor membrane component 2 (PGRMC2) regulate follicle development and maturation. Their mRNA expression was assessed in peripheral blood mononuclear cells (PBMC) of normal and poor responders, during ovarian stimulation.

DESIGN

Fifty-two normal responders and 15 poor responders according to the Bologna criteria were enrolled for IVF and intracytoplasmic sperm injection and stimulated with 200 IU of follitrophin alpha and gonadotrophin-releasing hormone antagonist. HCG was administered for final oocyte maturation. On days 1, 6 and 10 of stimulation, blood samples were obtained, serum hormone levels were measured, RNA was extracted from PBMC and real-time polymerase chain reaction was carried out to identify the mRNA levels. Relative mRNA expression of each gene was calculated by the comparative 2^-DDCt method.

RESULTS

Differences between mRNA levels of each gene on the same time point between the two groups were not significant. PGRMC1 and PGRMC2 mRNA levels were downregulated, adjusted for ovarian response and age. Positive correlations between PGRMC1 and AR (standardized beta = 0.890, P < 0.001) from day 1 to 6 and PGRMC1 and LHB (standardized beta = 0.806, P < 0.001) from day 1 to 10 were found in poor responders. PGRMC1 and PGRMC2 were positively correlated on days 6 and 10 in normal responders.

CONCLUSIONS

PGRMC1 and PGRMC2 mRNA are significantly decreased during ovarian stimulation, with some potential differences between normal and poor responders.

Follicle-stimulating hormone receptors expression in ovine corpora lutea during luteal phase: effect of nutritional plane and follicle-stimulating hormone treatment

Corpus luteum (CL), a transient endocrine gland critical for reproductive cyclicity and pregnancy maintenance, is controlled by numerous regulatory factors. Although LH is widely recognized as the major regulator, other factors may also affect luteal functions. It has been demonstrated that FSH receptors (FSHR) are expressed not only in ovarian follicles but also in other tissues within the reproductive tract, including the CL. To evaluate FSHR expression in nontreated (nonsuperovulated; experiment 1) or FSH-treated (superovulated; experiment 2) sheep fed a control (C; maintenance), excess (O; 2 × C), or restricted (U; 0.6 × C) diet, CL were collected at the early, mid and/or late luteal phases (n = 5-7 per group). Protein and messenger RNA (mRNA) expression of FSHR were detected in the CL from all groups using immunohistochemistry followed by image analysis and quantitative RT-PCR, respectively. Follicle-stimulating hormone receptor was immunolocalized to steroidogenic small and large and nonsteroidogenic luteal cells. In both experiments, FSHR protein expression was not affected by stage of luteal development or diet. In experiment 1, expression of mRNA for all FSHR variants was greater (P <0.02 to 0.0003) at the late phase than mid or early luteal phase, and in experiment 2, it was greater (P < 0.001) at the mid than early luteal phase. Plane of nutrition did not affect FSHR mRNA expression. Comparison of FSH-treated with nontreated ewes demonstrated that FSH increased FSHR protein expression by 1.5- to 2-fold (P < 0.0001) in all groups, and mRNA expression by 7- to 30-fold (P < 0.001) for (1) FSHR-1 in all groups except U at the early luteal phase, (2) FSHR-2 in C, O, and U at the mid-phase, but not early luteal phase, and (3) FSHR-3 in U at the mid-luteal phase. Our data demonstrate that (1) FSHRs are expressed in ovine CL at several stages of luteal development, (2) FSHR protein expression does not change during the luteal phase and is not affected by diet, (3) FSHR mRNA expression not only depends on the stage of the estrous cycle but also not affected by diet in nonsuperovulated or superovulated ewes, and (4) in vivo FSH treatment enhanced FSHR protein and/or mRNA expression in the CL depending on diet and phase of the estrous cycle. Presence of FSHR in the CL indicates a regulatory role of FSH in luteal function in sheep. As very little is known about the possible role of FSH and FSHR in luteal functions, further studies should be undertaken to elucidate the endocrine, molecular, and cellular mechanisms of FSH effects on the CL.

Characteristics of endometriosis: A case-cohort study showing elevated IgG titers against the TSH receptor (TRAb) and mental comorbidity

OBJECTIVES

Endometriosis has been associated with a wide range of factors. The disease share immunological features with autoimmune diseases, and the prevalence of both hypo- and hyperthyroidism has been reported to be increased. However, the associations have to be confirmed and the mechanisms explored. The aim of this observational study was to investigate socioeconomic factors, lifestyle habits, and somatic and mental comorbidities in endometriosis compared to the general population.

STUDY DESIGN

In all, 172 women with endometriosis completed a study questionnaire and were interviewed regarding socioeconomic factors, lifestyle habits, psychological well-being, and medical history. Bowel symptoms were measured by the Visual Analogue Scale for Irritable Bowel Syndrome (VAS-IBS). Serum was analyzed for IgG levels of TSH receptor antibodies (TRAb) and anti-thyroid peroxidase (TPO) antibodies. Women from the general population served as controls. Differences were calculated by logistic regression, adjusted for confounders.

RESULTS

Alcohol intake, leisure time physical activity, body mass index and asthma were inversely, whereas IBS was positively associated with endometriosis. Hypothyroidism and anti-TPO antibodies did not associate, but elevated TRAb antibody titers were associated with endometriosis (odds ratio (OR): 539.26; 95% confidence interval (CI): 114.29-2544.32 for highest versus lowest tertile; p for trend < 0.001). Impaired psychological well-being (p for trend = 0.003) and current intake of antidepressant medication (OR: 3.54; 95% CI: 1.22-10.28; p = 0.020) associated with endometriosis, and impaired psychological well-being correlated with all gastrointestinal symptoms measured (all p < 0.001).

CONCLUSIONS

Lifestyle habits and asthma are inversely associated, and IBS and impaired psychological well-being are positively associated with endometriosis. TRAb titers are associated with endometriosis, supporting a link between endometriosis, autoimmunity and thyroid pathophysiology, although overt thyroid diseases do not associate.

Vitamin D and Endometrium: A Systematic Review of a Neglected Area of Research

Growing evidence supports a role of vitamin D (VD) in reproductive health. Vitamin D receptor (VDR) is expressed in the ovary, endometrium, and myometrium. The biological actions of VD in fertility and reproductive tissues have been investigated but mainly using animal models. Conversely, the molecular data addressing the mechanisms underlying VD action in the physiologic endometrium and in endometrial pathologies are still scant. Levels of VDR expression according to the menstrual cycle are yet to be definitively clarified, possibly being lower in the proliferative compared to the secretory phase and in mid-secretory compared to early secretory phase. Endometrial tissue also expresses the enzymes involved in the metabolism of VD. The potential anti-proliferative and anti-inflammatory effects of VD for the treatment of endometriosis have been investigated in recent years. Treatment of ectopic endometrial cells with 1,25(OH)₂D₃ could significantly reduce cytokine-mediated inflammatory responses. An alteration of VD metabolism in terms of increased 24-hydroxylase mRNA and protein expression has been demonstrated in endometrial cancer, albeit not consistently. The effect of the active form of the vitamin as an anti-proliferative, pro-apoptotic, anti-inflammatory, and differentiation-inducing agent has been demonstrated in various endometrial cancer cell lines.

Follicle stimulating hormone receptor protein is expressed in ovine uterus during the estrous cycle and utero-placenta during early pregnancy: An immunohistochemical study

Follicle stimulating hormone (FSH) is a well characterized gonadotropin that controls primarily development and functions of ovarian follicles in mammalian species. FSH binds to a specific G protein-coupled receptor (FSHR) belonging to the glycoprotein hormone receptor family that plays an essential role in reproduction. Although the primary location of FSHR is in the gonads (mainly in ovarian follicles), FSHR protein and/or mRNA have also been detected in extragonadal female reproductive tissues including embryo, placenta, endometrium, cervix, ovarian cancer tissues, and/or endometriotic lesions in several species. To determine the pattern of FSHR expression in the uterus and placenta, uterine tissues were collected at the early, mid- and/or late luteal phases of the estrous cycle from non-treated or FSH-treated ewes, and utero-placental tissues were collected during early pregnancy followed by immunohistochemistry and image generation. FSHR was immunolocalized to several uterine and utero-placental compartments including luminal epithelium, endometrial glands and surrounding stroma, myometrium, and endothelium and vascular smooth muscle cells in endometrium, myometrium and mesometrium. Intensity of staining and distribution of FSHR in selected compartments differed and seems to depend on the stage of the estrous cycle or pregnancy, and FSH-treatment. These novel data demonstrate differential expression of FSHR protein indicating that FSH plays a specific role in regulation of uterine and utero-placenta functions in sheep.

Expression of progesterone receptor protein in the ovine uterus during the estrous cycle: Effects of nutrition, arginine and FSH

To evaluate expression of progesterone receptor (PGR) AB in follicle stimulating hormone (FSH)-treated or non-treated sheep administered with arginine (Arg) or saline (Sal) fed a control (C), excess (O) or restricted (U) diet, uterine tissues were collected at the early, mid and/or late luteal phases. In exp. 1, ewes from each diet were randomly assigned to one of two treatments, Arg or Sal administration three times daily from day 0 of the first estrous cycle until uterine tissue collection. In exp. 2, ewes were injected twice daily with FSH on days 13-15 of the first estrous cycle. Uterine tissues were immunostained to detect PGR followed by image analysis. PGR were detected in luminal epithelium (LE), endometrial glands (EG), endometrial stroma (ES), myometrium (Myo), and endometrial and myometrial blood vessels. The percentage of PR-positive cells and/or intensity of staining were affected by phase of the estrous cycle, plane of nutrition, and/or FSH but not by Arg. In exp. 1, percentage of PGR-positive cells in LE and EG but not in ES and Myo was greater at the early and mid than late luteal phase, was not affected by plane of nutrition, and was similar in LE and EG. Intensity of staining was affected by phase of the estrous cycle and plane of nutrition in LE, EG and Myo, and was the greatest in LE, less in EG, and least in ES and Myo. In exp. 2, percentage of PGR-positive cells in LE, EG, ES and Myo was affected by phase of the estrous cycle, but not by plane of nutrition; was greater at the early than mid luteal phase; and was greatest in LE and EG, less in luminal (superficial) ES and Myo and least in deep ES. Intensity of staining was affected by phase of the estrous cycle and plane of nutrition in all compartments but ES, and was the greatest in LE and luminal EG, less in deep EG, and least in ES and Myo. Comparison of data for FSH (superovulated) and Sal-treated (non-superovulated) ewes demonstrated that FSH affected PR expression in all evaluated uterine compartments depending on plane of nutrition and phase of the estrous cycle. Thus, PGR are differentially distributed in uterine compartments, and PGR expression is affected by nutritional plane and FSH, but not Arg depending on phase of the estrous cycle. Such changes in dynamics of PGR expression indicate that diet plays a regulatory role and that FSH-treatment may alter uterine functions.

Thyroid function and autoimmunity during ovarian stimulation for intracytoplasmic sperm injection

The aim of the present study was to assess changes in thyroid function and thyroid autoimmunity (TAI) throughout ovarian stimulation (OS) for intracytoplasmic sperm injection (ICSI) and the association of these changes with ICSI outcome. A flexible gonadotrophin-releasing hormone (GnRH) antagonist protocol was used in 42 women and their thyroid function and TAI were assessed at baseline and five times during OS (Days 3 and 5 of the menstrual cycle, the day of hCG administration, the day of ovum pick-up and the day of the pregnancy test). The primary outcome measure was the change in thyroid function throughout OS. No overall change was recorded in thyrotropin-stimulating hormone (TSH) concentrations throughout OS (P = 0.066). In women who became pregnant (n = 8), an increase in TSH concentrations was noted on the day of the pregnancy test compared with Day 3 of the menstrual cycle (3.410 ± 1.200 vs 2.014 ± 0.950 μIU mL–1, respectively; P = 0.001; mean ± s.d.). TAI was present in 11 of 42 women. Biochemical pregnancy was negatively correlated with changes in TSH (r = –0.7, P = 0.004). No such association was noted regarding the live birth rate. The present study provides evidence that TSH concentrations could increase during OS, especially in women who become pregnant.

Non-invasive prediction of implantation window in controlled hyperstimulation cycles: Can the time from the menstrual day at embryo transfer to expected menstrual cycle give a clue?

Objective:

The aim of this study was to assess whether the time from the menstrual day at embryo transfer to expected menstrual cycle (TETEMC) is associated with the implantation in women with regular cycles or not.

Materials and Methods:

Forty women with successful implantation and forty women without implantation with regular cycles were randomly selected from prospectively collected database of assisted reproductive technology clinic of Zeynep Kamil Women And Children’s Health Training and Research Hospital. TETEMC was calculated for each case to assess relationship with the successful implantation.

Results:

Comparison of groups revealed significant differences with regard to TETEMC and the menstrual period (p<0.05).

In ROC analyses both the TETEMC (AUC=0.824, p<0.001) and the menstrual period (AUC=0.797, p<0.001) were significant predictors for clinical pregnancy. Cut off value for the menstrual period was found to be 27.5 days with 82.6% sensitivity and 65% specificity. Cut off value for TETEMC was 11.5 days with 75% sensitivity and 63.2% specificity.

Conclusion:

Longer menstrual cycle and the TETEMC seem to be associated with the implantation failure.

Donor TSH level is associated with clinical pregnancy among oocyte donation cycles

PURPOSE

The purpose of the study is to evaluate the association between donor TSH level (independent of recipient TSH level) and recipient pregnancy outcome among fresh donor oocyte IVF cycles.

METHODS

This is a retrospective cohort study investigating 232 consecutive fresh donor-recipient cycles (200 total oocyte donors) at an academic medical center. Main outcome measures include clinical pregnancy and live birth.

RESULTS

Cycles were categorized into two groups based on donor TSH level (< 2.5 and ≥ 2.5 mIU/L). After controlling for multiple donor and recipient characteristics, the probability of clinical pregnancy was significantly lower among donors with TSH levels ≥2.5 mIU/L compared to those with TSH values <2.5 mIU/L (43.1 %, 95 % CI 28.5-58.9, versus 66.7 %, 95 % CI 58.6-73.9, respectively, p = 0.01). The difference in live birth rates between the two groups did not achieve statistical significance (43.1 %, 95 % CI 28.8-58.6, versus 58.0 %, 95 % CI 50.0-65.6, respectively, p = 0.09).

CONCLUSIONS

Donor TSH level, independent of recipient TSH level, is associated with recipient clinical pregnancy. These findings suggest that thyroid function may impact the likelihood of pregnancy at the level of the oocyte.

Fertility biomarkers to estimate metabolic risks in women with polycystic ovary syndrome

PURPOSE

We sought to evaluate the relationship between the polycystic ovary syndrome (PCOS)-defining characteristics and the risk of developing metabolic complications in women presenting with complaints of infertility and/or menstrual irregularities and subsequently diagnosed with PCOS.

METHODS

This was a cross-sectional study. Women presenting with complaints of infertility and/or irregular menses and diagnosed with PCOS by the Rotterdam criteria, underwent endocrine, metabolic, and ultrasound assessment in the early follicular phase. Reproductive and metabolic parameters were included in regression analysis models with the PCOS-defining characteristics; ROC curves were calculated for the significant predictors.

RESULTS

Three hundred and seventy-four women with PCOS were included in our study. Oligo-anovulation, menstrual irregularities, and hirsutism were not predictive of any of the variables. Ovarian volume, follicle count, and biochemical hyperandrogenism were predictors for hormonal, metabolic, and endometrial complications. The relationships were independent of age and body mass index. ROC curves identified lower cut-off values of the PCOS-defining characteristics to predict patients' risks of hyperinsulinemia, dyslipidemia, and glucose intolerance.

CONCLUSIONS

Adverse metabolic effects of PCOS are already present in women at the time they present complaining of infertility and/or irregular menses. Hyperandrogenism and ultrasound can assist in predicting the patients' concomitant metabolic abnormalities and can aid physicians in tailoring counseling for effective preventive strategies.