Towards a Better Understanding of Endometriosis-Related Infertility: A Review on How Endometriosis Affects Endometrial Receptivity

Peri-implantation treatment with TNF-α inhibitor for endometriosis and/or adenomyosis women undergoing frozen-thawed embryo transfer: A retrospective cohort study

PROBLEM

Endometriosis and adenomyosis have common pathogenesis and close relationship, with multi-factors involved in related infertility and IVF failure. They lead to anatomical changes, ovarian reserve reduction, endocrine abnormalities, altered endometrial receptivity and immunological dysfunction. Collective evidence indicate that abnormal function of immune cells and secretion of cytokines are closely related to reproductive outcomes among the women. Some studies showed that increased secretion of tumor necrosis factor alpha (TNF-α) led a key role in pro-inflammatory response in women with endometriosis/adenomyosis.TNF-a is embrryotoxic and receptivity impairing. Therefore, immunotherapy is a targeted therapeutic strategy apart from routine treatment. TNF-α inhibitors such as etanercept and adalimumab were shown to reduce the embryotoxic and anti-inflammatory effects to increase IVF pregnancy rates in recurrent implantation failure or endometrioma patient. However, there's no evidence about the use of adalimumab for patients with endometriosis and/or adenomyosis undergoing Frozen embryo transfer(FET).

METHOD OF STUDY

A retrospective analysis of 141 women with endometriosis and/or adenomyosis undergoing FET from January 2021 to Jun 2023 was conducted.They were 20-42 years old, with or without previous implantation failure. Endometriosis was diagnosed by laparoscopy during their infertility workup and adenomyosis was confirmed by vaginal ultrasound screening. GnRH agonist and hormone replacement treatment (HRT) or HRT were taken for endometrium preparation according to doctor's evaluation and preference. Before and after embryo transfer, 84 women were treated with Adalimumab and 57 patients were untreated. Implantation rate, clinical pregnancy rate, ongoing pregnancy rate and live birth rate were compared between the two groups.

RESULTS

The demographics and baseline characteristics between the two groups were comparable. Stage of embryo transferred and number of embryo transferred were comparable between the two groups (p = 0.227 and p = 0.204 separately). The regimen of endometrium preparation was similar too(p = 0.907). The implantation rate was significantly improved in study group (28.09 % vs 49.18 %, X2=9.515, P = 0.002). The clinical pregnancy rate was much lower in control group comparing with TNF-α inhibitor treatment group (42.11 % vs 60.71 %, X2=4.723, P = 0.029). There was no significant difference between the two groups as for ongoing pregnancy rate (38.60 % vs 52.38 %, X2=2.591, P = 0.107)and live birth rate (36.84 % vs 47.62 %, X2=1.606, P = 0.205). Following adjustment for age, BMI, number of prior failed transfer, stage of embryo transferred in a multiple logistic analysis, patients treated without TNF-α inhibitor had a significant lower CPR (ORadj 0.45, 95 %CI 0.22-0.92, p = 0.029) and a similar probability for OPR (ORadj 0.56, 95 %CI 0.28-1.12) and LBR (ORadj 0.62, 95 %CI 0.31-1.26) as compared with patients with TNF-α inhibitor treatment. However, an obvious trend of improvement of LBR was observed and it's clinical relevant for the patients.

CONCLUSION

In women with endometriosis and/or adenomyosis, peri-implantation treatment with TNF-α inhibitor increased implantation rate and clinical pregnancy rate significantly compared with control group in FET cycles. The ongoing pregnancy rate and live birth rate were not significant different, while the difference was clinical relevant.

MicroRNAs as Biomarkers and Therapeutic Targets in Female Infertility

The study of microRNAs (miRNAs) has emerged in recent decades as a key approach to understanding the pathophysiology of many diseases, exploring their potential role as biomarkers, and testing their use as future treatments. Not only have neurological, cardiovascular diseases, or cancer benefited from this research but also infertility. Female infertility, as a disease, involves alterations at multiple levels, such as ovarian and uterine alterations. This review compiles the latest studies published in humans that link female disorders that affect fertility with altered miRNA profiles. Studies on ovarian alterations, including diminished ovarian reserve (DOR), poor ovarian response to stimulation (POR), premature ovarian insufficiency (POI), and polycystic ovary syndrome (PCOS), are summarized and classified based on the expression and type of sample analyzed. Regarding uterine disorders, this review highlights upregulated and downregulated miRNAs primarily identified as biomarkers for endometriosis, adenomyosis, decreased endometrial receptivity, and implantation failure. However, despite the large number of studies in this field, the same limitations that reduce reproducibility are often observed. Therefore, at the end of this review, the main limitations of this type of study are described, as well as specific precautions or safety measures that should be considered when handling miRNAs.

Histopathologic characteristics of term placentas in singleton pregnancies in women with endometriosis-related infertility after ART treatment: case-control study

OBJECTIVES

Endometriosis is one of the leading causes of infertility, due to negative impact on ovarian folliculogenesis and endometrial receptivity. Literature show that endometriosis could be associated with perinatal complications such as preterm birth (PTB) and preeclampsia (PE). Authors hypothesized that women with endometriosis-related infertility conceived by assisted reproductive technology (ART) treatment have higher frequency of placental disorders. Main outcome is the occurrence of histopathologic alterations of term placentas in singleton pregnancies of women with endometriosis conceived by ART treatment, compared to healthy women with infertility due to male factor (MF) conceived by ART and to healthy women with spontaneous pregnancies. Secondary outcome include the occurrence of perinatal complications and the relationship of endometriosis and placental histopathologic characteristics.

METHODS

Single-center, case-control study of term placentas that were collected within Department of Obstetrics and Gynecology of University Hospital Center (UHC) Split and analyzed in the Pathology department of the same hospital, by one senior perinatal pathologist. Histopathologic analysis was reported using Amsterdam Placental Workshop Group Consensus. All the noted placental lesions were divided into following categories: anatomic, inflammatory, villous maturation and vascular malperfusion disorders. Required sample size was 80 placentas, and study results were reported with descriptives, and analyzed with chi-squared, Fisher's exact test and Kruskal-Wallis ANOVA. Multivariate regression analysis was carried with adjustment for confounding factors. Ethics approval: Class n. 520-03/24-01/83.

RESULTS

Study included term placentas of 107 women, of which 36 were women with endometriosis conceived by ART, 31 were healthy women with MF infertility conceived by ART and 40 healthy women with spontaneous pregnancies. Endometriosis women were predominantly primiparas, with longer infertility duration. Endometriosis group had higher occurrence of early pregnancy bleeding and imminent preterm labor. Endometriosis and MF groups had higher occurrence of Cesarian delivery (CS), while endometriosis group had newborns with lowest birthweight. Endometriosis group had shorter placental cords (PC), higher rates of increased syncytial knotting and vascular malperfusion disorders (subchorionic and perivillous fibrin, intervillous thrombosis, high grade fetal vascular malperfusion). Finally, endometriosis is showed to be associated with increased syncytial knots' formation and PC hypercoiling, after adjustment for confounding factors in the multivariate regression analysis.

CONCLUSIONS

Despite low rates of perinatal complications, we report endometriosis to have higher occurrence of increased syncytial knotting and vascular malperfusion placental disorders, compared to control groups. Endometriosis is also associated with increased syncytial knotting and PC hypercoiling. Further studies are needed to elucidate the endometriosis impact on endometrial receptivity and immunopathogenesis in placental disorders and perinatal complications.HighlightsEndometriosis women were predominantly primiparas, with longer infertility duration.Endometriosis group had higher occurrence of early pregnancy bleeding and imminent preterm labor. Moreover, endometriosis and MF groups had higher occurrence of Cesarian delivery, while endometriosis group had newborns with lowest birthweight.Endometriosis group had shorter placental cords, higher rates of increased syncytial knotting and vascular malperfusion lesions.Endometriosis is showed to be associated with increased syncytial knots formation and hypercoiling of placental cord, after adjustment for confounding factor.

Effects of various controlled ovarian hyperstimulation protocols and surgery on pregnancy outcomes in women with endometriosis

Endometriosis is a common gynecological condition in women of childbearing age that causes symptoms such as menstrual changes and dysmenorrhea, and is also a major cause of infertility. Therefore, women with endometriosis usually need to use assisted reproductive technology (ART), such as in vitro fertilization or intracytoplasmic sperm injection, to increase their chances of conceiving. Numerous clinical observations and studies have indicated that endometriosis can affect the success of ART, such that women with endometriosis who use ART have a lower live-birth rate than those without endometriosis who use ART. Therefore, this article reviews the impact of various controlled ovarian hyperstimulation protocols and surgery on the pregnancy outcomes of women with endometriosis using ART to explore the selection of individualized treatment.

Dendritic cells under the control of the preimplantation embryo secretome: an in vitro study

OBJECTIVE

To study the crosstalk between maternal immune cells and the developing embryo by investigating the immunogenic properties of human blastocyst spent media (SM) on dendritic cells.

METHODS

In this prospective multicenter experimental study, human preimplantation embryo spent media were collected after blastocyst formation, grouped based on successful or unsuccessful implantation, and analyzed by protein array or used to stimulate monocyte derived dendritic cells (moDC). The immunomodulatory properties of SM on moDC were investigated by analyzing changes in phenotype, cytokine secretion, indoleamine 2,3-dioxygenase (IDO) activity, and ability to activate T cells.

RESULTS

A plethora of cytokines and growth factors secreted from preimplantation embryos was detected. Exposure to embryo SM altered the phenotype of moDC in a manner dependent on the implantation outcome. Specifically, SM from non-implanted embryos increased the expression of co-stimulatory molecules and activation markers on moDC. Furthermore, SM treated dendritic cells secreted low levels of cytokines and growth factors and were able to stimulate naïve T cells. Activation of IDO was decreased in moDC after stimulation with SM.

CONCLUSIONS

Our findings show that human preimplantation embryos secrete an abundance of molecules with the ability to significantly affect and even regulate immune cells in their environment.

Associations between cytokines and the risk of female and male infertility: A two-sample Mendelian randomization analysis

PURPOSE

Observational studies have linked cytokines to the occurrence of female and male infertility. However, it is not clear how biomarkers of inflammation are causally related to infertility. To explore whether genetic variants in circulating cytokines are associated with the pathogenesis of infertility, we performed two-sample Mendelian randomization (MR) analysis.

METHODS

A total of 31,112 individuals of European ancestry were included in a genome-wide association study (GWAS) of 47 circulating cytokines as instrumental variables (IVs). Outcome data were female infertility, including four different subtypes, and male infertility, from the FinnGen consortium. Five MR methods, including inverse-variance weighted (IVW), MR-Egger, simple mode, weighted median, and weighted mode were employed to examine the genetic association between cytokines and the risk of female infertility and male infertility. The false discovery rate (FDR) was controlled using the Benjamini-Hochberg method.

RESULTS

After FDR correction, cis-protein quantitative trait locus (cis-pQTL) instruments showed that the cytokines GROa and MCSF were positively associated with female infertility. In analyses of subtypes of female infertility, eotaxin and sICAM were inversely associated with ovulation-related infertility; MCP3 alone was positively associated with uterus-related infertility; GROa and MCSF were positively correlated with infertility of cervical, vaginal, and other or unspecified origin; and MIP1a was negatively correlated with tubal origin infertility. The cytokines HGF, IL-2ra, and RANTES were positively correlated with male infertility. Similar findings were obtained in sensitivity analyses. There was no evidence of pleiotropy or heterogeneity in the results.

CONCLUSION

These findings contribute to current understanding of the role of cytokine biomarkers in the etiology of female and male infertility. Furthermore clinical experimental validation is required to evaluate the potential of these cytokines as biomarkers.

The effect of pentoxifylline and different types of exercise training on coagulation factors in a rat endometriosis model

Objectives

This study evaluated the effects of high-intensity interval training (HIIT), moderate-intensity continuous training (MICT), and pentoxifylline (PTX) on coagulation factors, including the amount and percentage of lymphocytes, PLC, PLR, aPTT, PT, PT.I.N. R in a model of rats with endometriosis.

Methods

Endometriosis was surgically induced in female Sprague-Dawley rats. The rats with confirmed endometrial implants were divided into control, MICT, pentoxifylline (D), HIIT+D, and MICT+D, HIIT groups. D and exercise interventions were performed for eight weeks. Then, the macroscopic size of endometriosis lesions was measured, and inflammatory factors (count and percentage of lymphocytes) and coagulation factors, including PLC, PLR, aPTT, PT, PT.I.N. R, and PLR in blood samples were evaluated.

Results

D significantly decreased the volume of lesions and significantly increased PT and PT.I.N. R in blood. HIIT decreased the volume of lesions and significantly increased PT. MICT did not cause significant effects on the target variables. MICT+D decreased the volume of lesions. HIIT+D significantly decreased the volume of lesions and PLC and increased aPTT as well as the count and percentage of lymphocytes, PT, and PT.I.N. R, and decreased PLR.

Conclusions

All interventions(except for MICT) especially HIIT+D and D by priority, induced a significant effect on reducing some indices of inflammation and coagulation.

Reproductive Immunology and Pregnancy 3.0

This Special Issue, the third dedicated to reproductive immunology and pregnancy, is another review of the latest trends in research topics in this field [...].

The Pathological Role of miRNAs in Endometriosis

Association studies investigating miRNA in relation to diseases have consistently shown significant alterations in miRNA expression, particularly within inflammatory pathways, where they regulate inflammatory cytokines, transcription factors (such as NF-κB, STAT3, HIF1α), and inflammatory proteins (including COX-2 and iNOS). Given that endometriosis (EMS) is characterized as an inflammatory disease, albeit one influenced by estrogen levels, it is natural to speculate about the connection between EMS and miRNA. Recent research has indeed confirmed alterations in the expression levels of numerous microRNAs (miRNAs) in both endometriotic lesions and the eutopic endometrium of women with EMS, when compared to healthy controls. The undeniable association of miRNAs with EMS hints at the emergence of a new era in the study of miRNA in the context of EMS. This article reviews the advancements made in understanding the pathological role of miRNA in EMS and its association with EMS-associated infertility. These findings contribute to the ongoing pursuit of developing miRNA-based therapeutics and diagnostic markers for EMS.

CREB1 Is Involved in miR-134-5p-Mediated Endometrial Stromal Cell Proliferation, Apoptosis, and Autophagy

The successful establishment of endometrial receptivity is a key factor in ensuring the fertility of ewes and their economic benefits. Hu sheep have attracted attention due to their high fecundity and year-round estrus. In this study, we found that in the luteal phase, the uterine gland density, uterine coefficient, and number of uterine caruncles of high-fertility Hu sheep were higher than those of low-fertility Hu sheep. Thousands of differentially expressed genes were identified in the endometrium of Hu sheep with different fertility potential using RNA sequencing (RNA-Seq). Several genes involved in endometrial receptivity were screened using bioinformatics analysis. The qRT-PCR analysis further revealed the differential expression of cAMP reactive element binding protein-1 (CREB1) in the Hu sheep endometrium during the estrous cycle. Functionally, our results suggested that CREB1 significantly affected the expression level of endometrial receptivity marker genes, promoted cell proliferation by facilitating the transition from the G1 phase to the S phase, and inhibited cell apoptosis and autophagy. Moreover, we observed a negative linear correlation between miR-134-5p and CREB1 in the endometrium. In addition, CREB1 overexpression prevented the negative effect of miR-134-5p on endometrial stromal cell (ESC) growth. Taken together, these data indicated that CREB1 was regulated by miR-134-5p and may promote the establishment of uterine receptivity by regulating the function of ESCs. Moreover, this study provides new theoretical references for identifying candidate genes associated with fertility.

Information Flow between Parents and Offspring Is Essential for Successful Development

Over the last several decades, the sciences of developmental biology and physiology have expanded and intertwined their scope enormously [...].