Glycodelin expression in the endometrium of healthy women and in the eutopic and ectopic endometrium of women with endometriosis

A combined clinical and specific genes' model to predict live birth for in vitro fertilization and embryo transfer patients

BACKGROUND

We aimed to develop an accurate model to predict live birth for patients receiving in vitro fertilization and embryo transfer (IVF-ET) treatment.

METHODS

This is a prospective nested case-control study. Women aged between 18 and 38 years, whose body mass index (BMI) were between the range of 18.5-24 kg/m2, who had an endometrium of ≥ 8 mm at the thickest were enrolled from 2018/9 to 2020/8. All patients received IVF-ET treatment and were followed up until Jan. 2022 when they had reproductive outcomes. Endometrial samples during the window of implantation (LH + 6 to 9 days) were subjected to analyze specific endometrial receptivity genes' expression using real-time PCR (RT-PCR). Patients were divided into live birth group and non-live birth group based on IVF-ET outcomes. Clinical signatures relevant to live birth were collected, analyzed, and used to establish a predictive model for live birth by univariate analysis (clinical model). Specific endometrial receptivity genes' expression was analyzed, selected, and used to construct a predictive model for live birth by The Least Absolute Shrinkage and Selection Operator (LASSO) analysis (gene model). Finally, significant clinical factors and genes were used to construct a combined model for predicting live birth using multivariate logistical regression (combined model). Different models' Area Under Curve (AUC) were compared to identify the most predictive model.

RESULTS

Thirty-nine patients were enrolled in the study, twenty-four patients had live births, fifteen did not. In univariate analysis, the odds of live birth for women with ovulation dysfunction was 4 times higher than that for women with other IVF-ET indications (OR = 4.0, 95% CI: 1.125 - 8.910, P = 0.018). Age, body mass index, duration of infertility, primary infertility, repeated implantation failure, antral follicle counting, ovarian sensitivity index, anti-Mullerian hormone, controlled ovarian hyperstimulation protocol and duration, total dose of FSH/hMG, number of oocytes retrieved, regiment of endometrial preparation, endometrium thickness before embryo transfer, type of embryo transferred were not associated with live birth (P > 0.05). Only ovulation dysfunction was used to construct the clinical model and its AUC was 0.688. In lasso analysis, GAST, GPX3, THBS2 were found to promote the risk of live birth. AUCs for GAST, GPX3, THBS2 reached to 0.736, 0.672, and 0.678, respectively. The gene model was established based on these three genes and its AUC was 0.772. Ovulation dysfunction, GAST, GPX3, and THBS2 were finally used to construct the combined model, reaching the highest AUC (AUC = 0.842).

CONCLUSIONS

Compared to the single model, the combined model of clinical (Ovulation dysfunction) and specific genes (GAST, GPX3, THBS2) was more accurate to predict live birth for IVF-ET patients.

Induction of Endometriosis in Nude Mice by Transplantation of Human Peritoneal Endometriotic Tissue

Purpose

Ectopic endometrial tissue is biochemically and functionally distinct from eutopic endometrium, including differences in receptivity to steroids and invasive potential. For this reason, using ectopic endometrial tissue to induce endometriosis in animal models may be of interest to understand better the pathogenesis of this disease. The aim of this study was to evaluate the potential of human pelvic endometriotic lesions (specifically red lesions) to implant into the peritoneal cavity of nude mice.

Methods

Human peritoneal endometriotic tissue (red lesions) was injected into the pelvic cavity of nude mice. The mice were euthanized after 5 or 14 days, lesions were recovered, and histological analysis was performed. Proliferative activity and neoangiogenesis of lesions were assessed after Ki67 and CD34 immunohistological staining, respectively.

Results

After 5 and 14 days, endometriotic tissue was found to have implanted onto intact mesothelium and reorganized into structured glands and stroma, forming endometriosis-like lesions. These lesions showed considerable proliferative activity and effective neoangiogenesis.

Conclusion

This model represents a promising tool to study in vivo implantation of human ectopic endometrium, which is dissimilar to eutopic endometrium. Moreover, this study shows that glands and stroma detached from red endometriotic lesions are able to implant in other peritoneal sites, as in a metastatic process.

Overexpression of Endometrial Estrogen Receptor-Alpha in The Window of Implantation in Women with Unexplained Infertility

Background

Failure in the endometrial receptivity may account for a significant number of infertility cases including unexplained infertility in women. Reduction in the endometrial estrogen receptor-alpha (ER-α) expression during implantation may be a critical event that coincides with the expression of specific genes and the formation of a receptive endometrium. The aim of the present study was to assess the expression of ER-α in the mid-secretory phase in the endometrium of women with unexplained infertility.

MATERIALS AND METHODS

This case-control study was carried out on randomly selected fertile (n=10) and infertile (n=16) women whose source of infertility remained unexplained. We evaluated the expression of ER-α and glycodelin- A (GdA) through mRNA level measurement with real-time polymerase chain reaction (PCR) in the endometrium of fertile women and patients suffering from unexplained infertility and fertile women. Endometrial biopsies of each subject were collected during a single menstrual cycle 7 days after the peak of luteinizing hormone (LH+7).

RESULTS

Endometrial expression level of ER-α was significantly (P<0.05) higher in the patients with unexplained infertility compared to the control. Significantly (P<0.05) lower levels of GdA expression were seen in women with unexplained infertility. A statistically non-significant negative correlation was observed between ER-α and GdA mRNA expression.

CONCLUSION

Our findings demonstrate that reduction in the endometrial GdA expression is associated with elevated expression of ER-α in mid-luteal phase. Disruption in the endometrial ER-α expression, which leads to defects in uterine receptivity, may contribute to unexplained infertility.

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.

Endometrial biomarkers for the non-invasive diagnosis of endometriosis

BACKGROUND

About 10% of reproductive-aged women suffer from endometriosis, which is a costly, chronic disease that causes pelvic pain and subfertility. Laparoscopy is the gold standard diagnostic test for endometriosis, but it is expensive and carries surgical risks. Currently, there are no non-invasive tests available in clinical practice that accurately diagnose endometriosis. This is the first diagnostic test accuracy review of endometrial biomarkers for endometriosis that utilises Cochrane methodologies, providing an update on the rapidly expanding literature in this field.

OBJECTIVES

To determine the diagnostic accuracy of the endometrial biomarkers for pelvic endometriosis, using a surgical diagnosis as the reference standard. We evaluated the tests as replacement tests for diagnostic surgery and as triage tests to inform decisions to undertake surgery for endometriosis.

SEARCH METHODS

We did not restrict the searches to particular study designs, language or publication dates. To identify trials, we searched the following databases: CENTRAL (2015, July), MEDLINE (inception to May 2015), EMBASE (inception to May 2015), CINAHL (inception to April 2015), PsycINFO (inception to April 2015), Web of Science (inception to April 2015), LILACS (inception to April 2015), OAIster (inception to April 2015), TRIP (inception to April 2015) and ClinicalTrials.gov (inception to April 2015). We searched DARE and PubMed databases up to April 2015 to identify reviews and guidelines as sources of references to potentially relevant studies. We also performed searches for papers recently published and not yet indexed in the major databases. The search strategies incorporated words in the title, abstract, text words across the record and the medical subject headings (MeSH).

SELECTION CRITERIA

We considered published peer-reviewed, randomised controlled or cross-sectional studies of any size that included prospectively collected samples from any population of reproductive-aged women suspected of having one or more of the following target conditions: ovarian, peritoneal or deep infiltrating endometriosis (DIE).

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data from each study and performed a quality assessment. For each endometrial diagnostic test, we classified the data as positive or negative for the surgical detection of endometriosis and calculated the estimates of sensitivity and specificity. We considered two or more tests evaluated in the same cohort as separate data sets. We used the bivariate model to obtain pooled estimates of sensitivity and specificity whenever sufficient data were available. The predetermined criteria for a clinically useful test to replace diagnostic surgery was one with a sensitivity of 94% and a specificity of 79%. The criteria for triage tests were set at sensitivity at or above 95% and specificity at or above 50%, which in case of negative results rules out the diagnosis (SnOUT test) or sensitivity at or above 50% with specificity at or above 95%, which in case of positive result rules in the diagnosis (SpIN test).

MAIN RESULTS

We included 54 studies involving 2729 participants, most of which were of poor methodological quality. The studies evaluated endometrial biomarkers either in specific phases of the menstrual cycle or outside of it, and the studies tested the biomarkers either in menstrual fluid, in whole endometrial tissue or in separate endometrial components. Twenty-seven studies evaluated the diagnostic performance of 22 endometrial biomarkers for endometriosis. These were angiogenesis and growth factors (PROK-1), cell-adhesion molecules (integrins α3β1, α4β1, β1 and α6), DNA-repair molecules (hTERT), endometrial and mitochondrial proteome, hormonal markers (CYP19, 17βHSD2, ER-α, ER-β), inflammatory markers (IL-1R2), myogenic markers (caldesmon, CALD-1), neural markers (PGP 9.5, VIP, CGRP, SP, NPY, NF) and tumour markers (CA-125). Most of these biomarkers were assessed in single studies, whilst only data for PGP 9.5 and CYP19 were available for meta-analysis. These two biomarkers demonstrated significant diversity for the diagnostic estimates between the studies; however, the data were too limited to reliably determine the sources of heterogeneity. The mean sensitivities and specificities of PGP 9.5 (7 studies, 361 women) were 0.96 (95% confidence interval (CI) 0.91 to 1.00) and 0.86 (95% CI 0.70 to 1.00), after excluding one outlier study, and for CYP19 (8 studies, 444 women), they were were 0.77 (95% CI 0.70 to 0.85) and 0.74 (95% CI 0.65 to 84), respectively. We could not statistically evaluate other biomarkers in a meaningful way. An additional 31 studies evaluated 77 biomarkers that showed no evidence of differences in expression levels between the groups of women with and without endometriosis.

AUTHORS' CONCLUSIONS

We could not statistically evaluate most of the biomarkers assessed in this review in a meaningful way. In view of the low quality of most of the included studies, the findings of this review should be interpreted with caution. Although PGP 9.5 met the criteria for a replacement test, it demonstrated considerable inter study heterogeneity in diagnostic estimates, the source of which could not be determined. Several endometrial biomarkers, such as endometrial proteome, 17βHSD2, IL-1R2, caldesmon and other neural markers (VIP, CGRP, SP, NPY and combination of VIP, PGP 9.5 and SP) showed promising evidence of diagnostic accuracy, but there was insufficient or poor quality evidence for any clinical recommendations. Laparoscopy remains the gold standard for the diagnosis of endometriosis, and using any non-invasive tests should only be undertaken in a research setting. We have also identified a number of biomarkers that demonstrated no diagnostic value for endometriosis. We recommend that researchers direct future studies towards biomarkers with high diagnostic potential in good quality diagnostic studies.

Selection of reliable reference genes in eutopic and ectopic endometrium for quantitative expression studies

PURPOSE

Physiological changes during menstrual cycle cause the endometrium and endometriosis to develop specific kind of tissues, especially in regard to the gene expression profiles, which may include also housekeeping genes, commonly used as reference genes (RGs) in quantitative studies. Reverse transcription, followed by quantitative polymerase chain reaction (RT-qPCR) is the most precise and commonly used method in gene expression studies. In order to reduce effects of technical approaches and biological variability of gene's expression level, the studies often employ RGs in experimental data normalization. However, the expression of RGs is not always stable and depends on several variables. Thus, the selection of appropriate RG is one of the most significant steps to obtain reliable results in RT-qPCR-based methods.

MATERIAL AND METHODS

With the usage of RT-qPCR, we researched the expression of seven genes (ACTB, B2M, G6PD, GAPD, GUSB, HPRT and PPIA) as reliable reference genes in eutopic and ectopic endometrial tissue specimens obtained during standard surgery of women of reproductive age. Stability of expression level was analyzed by the most universal MS Excel plug-ins including: geNorm, NormFinder and BestKeeper. The descriptive statistics were evaluated using Statistica software.

RESULTS

The distribution of threshold (Ct) values was not equal. We identified genes with higher expression level (referring to Ct values) such as ACTB and B2M, medium e.g., GAPD and low expression level, e.g., G6PD and HPRT. We demonstrated that the stability of the analyzed reference genes was not homogenous, and different algorithms pointed to PPIA, GAPD and B2M as the most stable ones in eutopic and ectopic endometrium. On the contrary to these, GUSB and G6PD were the most unstable ones.

CONCLUSIONS

In RT-qPCR-based analyses of gene expression level in eutopic and ectopic endometrium, we strongly recommend that a minimum of two reference genes are to be used and we determined that the most suitable seem to be PPIA and GAPD.

Effect of myomectomy on endometrial glutathione peroxidase 3 (GPx3) and glycodelin mRNA expression at the time of the implantation window

BACKGROUND

In fertile women, glycodelin and glutathione peroxidase 3 (GPx3) genes expression rises during the luteal phase, with a peak occurring during the implantation window. The expression of these genes decreases in women with myomas. To determine whether myomectomy would reverse glycodelin and GPx3 expression, we evaluated the transcript levels of these genes in the endometrium of patients before and after myomectomy.

METHODS

Expression of glycodelin and GPx3 genes were examined prospectively during the midluteal phase in the endometrium obtained from infertile women with myoma (n = 12) before and three months after myomectomy. Endometrial expression of these genes was evaluated using quantitative real-time RT-PCR.

RESULTS

Endometrial glycodelin mRNA expression levels (normalized to 18S rRNA expression) were increased significantly in endometrium of patients after myomectomy (P = 0.02). GPx3 mRNA expression was increased insignificantly after myomectomy (P = 0.43).

CONCLUSION

The results showed that myomectomy increased endometrial glycodelin (significantly) and GPx3 (not significantly) gene expression after 3 months. Study at different times and detecting expression of these genes can reveal more details.

The role of placental protein 14 in the pathogenesis of endometriosis

Placental protein 14 (PP-14) is the principal secretory phase product of endometrium and has been shown to inhibit cell immune function. But its role in the pathogenesis of endometriosis is controversy. The objective of this study is to determine the concentrations of PP-14 in peritoneal fluid (PF) and serum and PP-14 protein expression in endometriotic lesions in women with ovarian endometriosis (n = 75) when compared to women without endometriosis (n = 49) between day 7 and day 20 of their menstrual cycle. Concentrations of PP-14 in PF and serum as well as PP-14 protein expression in endometriotic lesions in women with and without endometriosis were evaluated by using enzyme-linked immunosorbent assay and immunohistochemical staining, respectively. Serum PP-14 concentrations were significantly increased in women with endometriosis (7.5 ± 1.4 ng/mL) compared to those in women without endometriosis (5.8 ± 0.9 ng/mL; P < .05) and statistically decreased after surgery and further reduced by using gonadotropin-releasing hormone agonist therapy (P < .05). However, the concentrations of PP-14 in PF did not reach a significant difference between women with and without endometriosis (P > .05). In women with endometriosis, scores of PP-14 protein expression in the lesions (n = 50, 2.2 [0~5.8]) were significantly correlated with serum PP-14 concentrations (n = 50, 7.6 ± 1.3 ng/mL; P < .01). Our results suggest that PP-14 may play an important role in the pathogenesis of endometriosis.

Selected cytokines and glycodelin A levels in serum and peritoneal fluid in girls with endometriosis

AIM

The aim of this study was to determine the role of serum and peritoneal interleukin (IL)-6, tumor necrosis factor (TNF)-α and glycodelin A levels as diagnostic markers of endometriosis in adolescent girls.

MATERIAL AND METHODS

The study encompassed 50 adolescent girls, aged 13-19 years, after menarche and with chronic pelvic pain who qualified for diagnostic laparoscopy. The patients were allocated into two groups: group I (endometriosis group) consisted of subjects with diagnosed endometriosis (n = 33, 66%) and group II (control group) included those whose laparoscopic examinations revealed no evidence of endometriosis (n = 17, 34%). IL-6, TNF-α and glycodelin A concentrations in serum and peritoneal samples were assessed using commercially available human enzyme-linked immunosorbent assay kits. The value of P < 0.05 was adopted as the level of statistical significance.

RESULTS

Compared with the control group, adolescent girls with endometriosis had significantly higher peritoneal fluid levels of: IL-6 (525.10 ± 1168.53 pg/mL vs 62.96 ± 82.35 pg/mL), TNF-α (5.79 ± 5.60 pg/mL vs 1.68 ± 1.24 pg/mL) and glycodelin A (94.24 ± 60.97 ng/mL vs 53.52 ± 41.43 ng/mL). Peritoneal IL-6, TNF-α and glycodelin A provided a good method of discrimination between subjects with endometriosis and controls. Using cut-off points for peritoneal fluid IL-6 (90.00 pg/mL), TNF-α (3.00 pg/mL) and glycodelin A (60.0 ng/mL), exceptionally high odds ratios (10.2; 14.6; 2.2) were obtained in the prediction of endometriosis in adolescents.

CONCLUSIONS

At the cut-off value of 3.00 pg/mL, peritoneal TNF-α can be a reliable screening marker for the prediction of endometriosis in adolescents, giving a 14.6-fold higher probability of endometriosis detection in girls with chronic pelvic pain.

Differences in the soluble HLA-G blood serum concentration levels in patients with ovarian cancer and ovarian and deep endometriosis

PROBLEM

The relationship between endometriosis and cancer has been widely discussed in the literature but is still not well clarified. Perhaps significantly, soluble human leukocyte antigen-G (sHLA-G) has been identified in the microenvironment of both ovarian cancer and endometrioma. The aim of this study has been to evaluate the sHLA-G levels in the blood sera of women with deep endometriosis and ovarian endometrioma over the course of the menstrual cycle and to compare to the levels of sHLA-G in the blood sera of women with ovarian cancer.

METHOD OF STUDY

In our study, we examined the blood sera obtained from 123 patients operated on because of ovarian cancer (65 cases), ovarian endometrioma (30 cases), and deep endometriosis (28 cases). We decided to compare the levels of sHLA-G in patients with endometriosis to those found in patients with ovarian cancer with respect to the menstrual cycle phases. The sHLA-G concentration level was measured by enzyme-linked immunosorbent assay kit.

RESULTS

The level of sHLA-G concentration in the blood serum of patients with deep endometriosis fluctuates over the course of the menstrual cycle, and during the proliferative and secretory phases, it remains at a high level comparable to that found in patients with ovarian cancer. By contrast, the level of sHLA-G concentration in the blood serum of patients with ovarian endometrioma fluctuates minimally over the course of the different menstrual cycle phases and, as in patients with ovarian cancer, it remains at high level during the proliferative phase.

CONCLUSION

sHLA-G blood serum concentration levels would seem to provide important information regarding the degree of immune system regulation disturbance in both ectopic endometrial cells and the cancer cell suppressive microenvironment.

Differentially expressed genes in eutopic and ectopic endometrium of women with endometriosis

OBJECTIVE

To elucidate the potential mechanisms involved in the physiopathology of endometriosis. We analyzed the differential gene expression profiles of eutopic and ectopic tissues from women with endometriosis.

DESIGN

Prospective laboratory study.

SETTING

University hospital.

PATIENT(S)

Seventeen patients in whom endometriosis was diagnosed and 11 healthy fertile women.

INTERVENTION(S)

Endometrial biopsy specimens from the endometrium of healthy women without endometriosis and from the eutopic and ectopic endometrium tissues of patients with endometriosis were obtained in the early proliferative phase of the menstrual cycle.

MAIN OUTCOME MEASURE(S)

Six paired samples of eutopic and ectopic tissue were analyzed by subtractive hybridization. To evaluate the expression of genes found by rapid subtraction hybridization methods, we measured CTGF, SPARC, MYC, MMP, and IGFBP1 genes by real-time polymerase chain reaction in all samples.

RESULT(S)

This study identified 291 deregulated genes in the endometriotic lesions. Significant expression differences were obtained for SPARC, MYC, and IGFBP1 in the peritoneal lesions and for MMP3 in the ovarian endometriomas. Additionally, significant differences were obtained for SPARC and IGFBP1 between the peritoneal and ovarian lesions. No significant differences were found for the studied genes between the control and the eutopic endometrium.

CONCLUSION(S)

This study identified 291 genes with differential expression in endometriotic lesions. The deregulation of the SPARC, MYC, MMP3, and IGFBPI genes may be responsible for the loss of cellular homeostasis in endometriotic lesions.