Endometritis: new time, new concepts

Challenges in Clinical Diagnosis and Management of Chronic Endometritis

Chronic endometritis (CE) is a local mucosal infectious and inflammatory disorder characterized by unusual filtration of CD138(+) endometrial stromal plasmacytes. CE is attracting attention due to its potential association with infertility of unknown etiology, repeated implantation failure, recurrent pregnancy loss, and several maternal/neonatal complications. Due to the variance in study design among researchers, universal diagnostic criteria remain to be established for the clinical diagnosis and management of CE. This review article aims to summarize current knowledge and provide insights into unsolved questions on CE to establish clinical guidelines for the disease from the viewpoint of human reproduction.

Additional dydrogesterone for the treatment of chronic endometritis treated with antibiotic in premenopausal women with endometrial polyps: a retrospective cohort study

Background

To assess the efficacy of dysdrogesterone in the treatment of chronic endometritis (CE) treated with antibiotic in premenopausal women with endometrial polyps (EPs).

Methods

Routine detection of endometrium was simultaneously conducted to determine whether there was CE by syndecan-1 (CD138), while women underwent hysteroscopic polypectomy in our hospital. Antibiotic was given for the treatment of CE. A total of 235 premenopausal women with CE who underwent hysteroscopic polypectomy were enrolled in the retrospective observational study. In the control group, single antibiotic was given for the treatment of CE form January 2016 to December 2018, and in the treatment group additional dydrogesterone was used from January 2019 to November 2020. Comparison of cure rates of CE with different treatment regimens was performed.

Results

The cure rates of CE in dydrogesterone and antibiotic combination group and the single antibiotic group were 85.2% and 74.3%, respectively, with overall cure rate of 80.0% (188/235). The combination group showed better effects regarding the cure rate of CE (P < .05). Multivariate analysis confirmed that the cure rate of CE was not affected by age, body mass index, number of EPs, the status of estrogen receptor and the status of progesterone receptor. Conversely, dydrogesterone and endometrial scratching were beneficial factors for cure rate increase with antibiotic treatment.

Conclusion

Combination of dydrogesterone and antibiotic was more effective for cure rate of CE than antibiotic alone in premenopausal women after hysteroscopic polypectomy. Endometrial scratching also contributed to the cure rate increase with antibiotic treatment.

Intrauterine LPS inhibited arcuate Kiss1 expression, LH pulses, and ovarian function in rats

In brief

Uterine inflammatory diseases are a major cause of infertility in humans and domestic animals. The current findings that intrauterine lipopolysaccharide is absorbed in systemic circulation and attenuates ovarian cyclic activities could provide a basis for developing novel treatments to improve fertility.

Abstract

Uterine inflammatory diseases are a major cause of infertility in humans and domestic animals. Circulating lipopolysaccharide (LPS), a bacterial endotoxin causing uterine inflammation, reportedly downregulates the hypothalamic-pituitary-gonadal axis to mediate ovarian dysfunction. In contrast, the mechanism whereby intrauterine LPS affects ovarian function has not been fully clarified. This study aimed to elucidate whether uterine exposure to LPS downregulates hypothalamic kisspeptin gene (Kiss1) expression, gonadotropin release, and ovarian function. Uterine inflammation was induced by intrauterine LPS administration to ovary-intact and ovariectomized female rats. As a result, plasma LPS concentrations were substantially higher in control rats until 48 h post injection, and the estrous cyclicity was disrupted with a prolonged diestrous phase. Three days post injection, the number of Graafian follicles and plasma estradiol concentration were reduced in LPS-treated rats, while numbers of Kiss1-expressing cells in the anteroventral periventricular nucleus and arcuate nucleus (ARC) were comparable in ovary-intact rats. Four days post injection, ovulation rate and plasma progesterone levels reduced significantly while gene expression of interleukin1β and tumor necrosis factor α was upregulated in the ovaries of LPS-treated rats that failed to ovulate. Furthermore, the number of Kiss1-expressing cells in the ARC and pulsatile luteinizing hormone (LH) release were significantly reduced in ovariectomized rats 24 h post injection. In conclusion, these results indicate that intrauterine LPS is absorbed in systemic circulation and attenuates ovarian function. This detrimental effect might be caused, at least partly, by the inhibition of ARC Kiss1 expression and LH pulses along with an induction of ovarian inflammatory response.

Microbiology of Human Follicular Fluid and the Vagina and Its Impact on in Vitro Fertilization Outcomes

PURPOSE

The present study aimed to identify microorganisms in follicular fluids and to investigate their association with in vitro fertilization (IVF) outcomes.

MATERIALS AND METHODS

This study was conducted as a prospective study of 49 infertile females undergoing IVF/intracytoplasmic sperm injection cycles between 2013 and 2016. Paired follicular fluid and vaginal secretions were collected on the day of ovum pick up and were cultured to detect microorganisms.

RESULTS

Fifteen women (30.6%) had no microorganisms in follicular fluid or vaginal swabs, 23 (46.9%) had microorganisms on vaginal swab alone, 3 (6.1%) had microorganisms in follicular fluid alone, and 8 (16.3%) had microorganisms in both follicular fluid and vaginal swabs. The same microorganisms were detected in both the follicular fluid and vaginal swabs of three women, while different microorganisms were detected between follicular fluid and vaginal swabs in five women. Follicular fluid microorganisms were not associated with embryo quality or clinical pregnancy rates during IVF cycles. However, significantly decreased implantation rates (9.1% vs. 29.4%, p=0.031) and clinical pregnancy rates on embryo transfer day 5 (0% vs. 83.3%, p=0.048) were observed in the group that was positive for vaginal pathogens.

CONCLUSION

Follicular fluid contains microorganisms that can differ from those in the vagina of the same women; however, they do not appear to be associated with embryo quality or clinical pregnancy rates in IVF cycles. In contrast, vaginal pathogens were found to be associated with worse implantation rates and clinical pregnancy rates in IVF cycles.

Inflammation-Related Molecules at the Maternal–Fetal Interface during Pregnancy and in Pathologically Altered Endometrium

The blastocyst expresses paternally derived alloantigens and induces inflammation during implantation. However, it is necessary for the onset of pregnancy. An abnormal response might result in a pathological course of pregnancy or pregnancy failure. On the other hand, a state of maternal immune tolerance is necessary to ensure the normal development of pregnancy by suppressing inflammatory processes. This article discusses recognized mechanisms and the significance of inflammatory processes for embryo implantation and pregnancy establishment. We would also like to present disorders involving excessive inflammatory response and their influence on events occurring during embryo implantation. The chain of correlation between the processes responsible for embryo implantation and the subsequent physiological course of pregnancy is complicated. Many of those interrelationships are still yet to be discovered. Undoubtedly, their recognition will give hope to infertile couples for the emergence of new treatments that will increase the chance of giving birth to a healthy child.

Chemerin: A Functional Adipokine in Reproductive Health and Diseases

As a multifaceted adipokine, chemerin has been found to perform functions vital for immunity, adiposity, and metabolism through its three known receptors (chemokine-like receptor 1, CMKLR1; G-protein-coupled receptor 1, GPR1; C-C motif chemokine receptor-like 2, CCRL2). Chemerin and the cognate receptors are also expressed in the hypothalamus, pituitary gland, testis, ovary, and placenta. Accumulating studies suggest that chemerin participates in normal reproduction and underlies the pathological mechanisms of certain reproductive system diseases, including polycystic ovary syndrome (PCOS), preeclampsia, and breast cancer. Herein, we present a comprehensive review of the roles of the chemerin system in multiple reproductive processes and human reproductive diseases, with a brief discussion and perspectives on future clinical applications.

Lincomycin Administration against Persistent Multi-Drug Resistant Chronic Endometritis in Infertile Women with a History of Repeated Implantation Failure

Chronic endometritis (CE) is an infectious disease of the uterine lining, which is characterized by endometrial stromal plasmacyte (ESPC) infiltration. CE is often seen in infertile women with a history of repeated implantation failure (RIF) following an in vitro fertilization-embryo transfer program, recurrent pregnancy loss, and unknown etiology. Oral antibiotic agents, such as doxycycline, metronidazole, ciprofloxacin, azithromycin, and moxifloxacin, have been prescribed and are effective in the treatment of CE. Multi-drug resistance (MDR), however, is an emerging issue, as in other medical fields. We report six cases of persistent MDR-CE in infertile women who were resistant to all the aforementioned antibiotic agents. The bacterial genera and microbial communities unique to persistent MDR-CE were not identified in their vaginal secretions and/or endometrial fluid. Oral lincomycin administration (14 days, 1500 mg/day) was effective in the eradication of ESPCs in these women. In the embryo transfer cycles following histopathologic confirmation of cure (elimination of ESPCs) of persistent MDR-CE, three out of them had a successful live birth.

Baogong decoction treats endometritis in mice by regulating uterine microbiota structure and metabolites

Endometritis is persistent inflammation caused by bacteria, which can lead to infertility. Although traditional Chinese medicine (TCM) has been used to treat endometritis, the underlying mechanism is still unclear. Here, Baogong Decoction (BGD), a TCM compound, was used to treat mouse endometritis induced by Escherichia coli (E. coli), and then 16S rRNA sequencing and non-targeted metabolomics were used to investigate the change of uterine microbiota and metabolomes in serum and uterine after BGD treatment. Finally, the therapeutic effect of potential metabolites for treating mouse endometritis screened by combined omics analyses was verified using pathological model. The results showed that BGD treatment could effectively treat endometritis associated with the increasing relative abundance of Firmicutes, Bacteroides, Lactobacillus and Lactococcus, and the decreasing relative abundance of Cupriavidus and Proteobacteria. 133 and 130 metabolites were found to be potential biomarkers in serum and uterine tissue respectively. In serum and tissues, dehydroepiandrosterone (DHEA) and catechol were significantly increased in the BGD treatment versus the inflammation group. Results of combined omics analyses demonstrated that DHEA was positively correlated with changes in microbiota. Results of pathological model demonstrated that DHEA could cure endometritis effectively associated with the decreasing infiltration of inflammatory cells and expression of inflammatory factors in the uterus. In summary, our results demonstrated that BGD could cure endometritis in mice by modulating the structure of the uterine microbiota and its metabolites, in which DHEA may be one of the main components of the therapeutic effect of BGD.

Multi-drug-resistant chronic endometritis in infertile women with repeated implantation failure: trend over the decade and pilot study for third-line oral antibiotic treatment

PURPOSE

To evaluate the yearly prevalence and annual transition of multi-drug-resistant-chronic endometritis (MDR-CE) in infertile women with a history of repeated implantation failure (RIF) and to establish the third-line antibiotic treatment regimen against MDR-CE.

METHODS

This retrospective/prospective cohort and pilot study included 3473 RIF women between April 2010 and September 2021. The endometrial stromal plasmacyte density index (ESPDI) was calculated in 3449 CD138-immunostained endometrial sections to evaluate CE. The microbiota in the vaginal secretions and endometrial fluid was compared between 17 patients with MDR-CE and 16 patients with antibiotics-sensitive CE. In a pilot study, oral moxifloxacin (400 mg/day, 10 days, n = 24) or azithromycin (500 mg/day, 3 days, n = 24) was administered to eligible patients with MDR-CE.

RESULTS

From April 2010 to March 2020, CE was detected in 31.4% of RIF women and MDR was detected in 7.8% of CE. While the prevalence of CE was stable for a decade, MDR in CE increased steadily (OR 8.27, 95% CI 2.58-26.43, p trend < 0.001). The bacterial species/communities unique to MDR-CE were not found. The histopathologic cure rate of MDR-CE was similar between the moxifloxacin and azithromycin groups (79.2% vs 75.0%, OR 1.27, 95% CI 0.32-4.89, p value 0.73), as well as reproductive outcomes in subsequent embryo transfer cycles.

CONCLUSION

In RIF women, MDR in CE increased over the decade. As a third-line treatment for MDR-CE, azithromycin may have a clinical advantage due to its shorter time administration periods.

CLINICAL TRIAL NUMBER

ClinicalTrials.gov Identifier: UMIN-CTR 000029449/000031909.

Investigation of the Relationship between Chronic Endometritis Manifestations under Hysteroscope and CD138 Expression

Methods

This study was performed to retrospectively analyze clinical cases of 523 CE patients from January 2018 to June 2020 that were confirmed by hysteroscopy before in vitro fertilization. Based on manifestations of CE under hysteroscopy, the cases were divided into three cohorts, i.e., hyperemia cohort where the patients had diffuse endometrium hyperemia; endometrial micropolyp cohort, and endometrial stroma edema and hyperplasia cohort. Small amount of endometrial tissue was collected from the patients, and CD138 IHC examination was performed. According to the results of CD138 IHC, positive patients were given antibiotic treatment (doxycycline 100 mg BID orally for 14 days), and hysteroscopy was performed again after treatment to check the efficacy of antibiotics.

Results

In the comparison of overall status for all patient cohorts, infertility type, BMI, bFSH, bLH, bP, bT, PRL, AMH, and CA125 were varied markedly across all cohorts (P < 0.05), with predominant incidences of polycystic ovary syndrome (PCOS) peaking within hyperemia cohort. Incidence/diagnostic rate for CD138 within hyperemia cohort was 10.06%, which was lower than the 63.16% in micropolyp cohort and 74% in edema and hyperplasia cohort (P < 0.05). No major variation existed within CD138 across micropolyp cohort/edema and hyperplasia cohort (P > 0.05). After CD138-positive CE patients were treated with antibiotics, the effective rate (0/16) within hyperemia cohort was lower than micropolyp cohort (73.61%, 53/72) and edema and hyperplasia cohort (83.24%, 154/185) (P < 0.05). The effective rate across micropolyp cohort/edema and hyperplasia cohort was not significantly different (P > 0.05).

Conclusion

Cases of diffuse endometrial hyperemia under hysteroscope had the lowest positive rate of CD138, and the effect of antibiotic treatment on these patients was poor. The positive rate of CD138 in patients with endometrial micropolyps and endometrial stroma edema and hyperplasia under hysteroscope was high, and the effect of antibiotic treatment was better.

Chronic endometritis in recurrent implantation failure: Use of prednisone and IVF outcome

In recurrent implantation failure patients (RIF), the main criteria for diagnosis of chronic endometritis, is the presence of plasma cells CD138⁺ in endometrial biopsy. The aim of the present study was to evaluate if treatment with prednisone, in patients with RIF and chronic endometritis, improve IVF outcome. A retrospective study was performed between 2019 and 2020. A total of 27 patients with RIF and an endometrial biopsy positive for CD56⁺ cells were enrolled. The treatment with prednisone 10 mg per day is began together with controlled ovarian stimulation (COS). Among endometrial biopsies, 13 (48.14%) were positive also for CD138 cells, and an antibiotic treatment was added. In all patients, after therapy, in the subsequent IVF cycle, the clinical pregnancy rate was 25.9% and the live birth rate was 22.2%. Analysing pregnancies according to the percentage of CD 56 cells on endometrial biopsy, the live birth rate in the subgroup of patients with marked endometritis (defined by the presence of >10% CD56⁺cells) was 29.41%, while in the subgroup with mild endometritis (CD 56 >5% and <10%) was 10%. In the subgroup with mild endometritis with CD 138 positive the live birth was 25%, while in patients with CD 138 negative no live birth were observed. In patients with RIF the count of at least two cell types (CD 138 and CD 56 cells) on endometrial biopsies is advisable. Our study suggests a benefit of prednisone and antibiotic treatment on live birth rate in a subsequent IVF cycle.

Diagnosing chronic endometritis: when simplification fails to clarify

Reproductive immunology has grown in importance in recent years and has even developed into a discipline of its own within the field of reproductive medicine. Many aspects of reproductive failure such as repeated implantation failure or recurrent miscarriages are, meanwhile, seen as a consequence of aberrant expression of immunological factors. This is reflected by the increasing number of tests for assessing and quantifying different immune cell types as well as by a wide range of immune therapies offered to a clientele consisting of desperate patients requesting additional ‘IVF tools’: first, what is still usually disregarded is the enormous plasticity and fluctuation of most immune cells in the genital tract; second, their still poorly characterized functions in the endometrial cycle: further, their partially unknown role in embryo implantation and in establishing a pregnancy; and third, the fact that one of the fundamental hypotheses of reproductive immunology—of note—the Medawar concept or ‘Medawar's Paradox’ of semi-allogeneic graft embryo, is partially based on an erroneous assumption, i.e. the immunologic rejection and tolerance of an embryo. In the present opinion article, we comment on the diagnostic procedures and therapy approaches for chronic endometritis within the scope of reproductive medicine.

Higher Chronic Endometritis Incidences within Infertile Polycystic Ovary Syndrome Clinical Cases

Background

Clinical cases of a polycystic ovarian syndrome (PCOS) have prolonged subclinical inflammation. Hysteroscopy has revealed worsened chronic endometritis (CE), particularly endometrial diffuse hyperemia, in PCOS patients. However, the possible relationships between PCOS and CE remain largely unexplored.

Methods

This retrospective-based investigation was conducted on 3336 infertile patients. The PCOS group consisted of 508 patients, while the non-POCS group consisted of 2828 individuals with normal ovarian function. Their clinical features and CE prevalence diagnosed with hysteroscopy were compared. The risk factors affecting the incidence of diffuse endometrial hyperemia were analyzed by binary logistic regression.

Results

The PCOS cohort and the non-PCOS cohort showed marked variations in age, body mass index (BMI), infertility (primary, secondary), basal hormone level (bFSH, bLH, bT, and PRL), anti-Müllerian hormone (AMH), and CA125 (P < 0.05). The prevalence of CE in PCOS women was 41.73% (212/508), markedly higher than the 28.50% in the non-PCOS cohort (806/2828). Variations within diffuse endometrial hyperemia prevalence were especially marked (P < 0.05). Furthermore, we found that the variables of BMI, bLH, bT, and AMH correlated with diffuse endometrial hyperemia.

Conclusions

CE prevalence was elevated in clinical cases of infertility associated with PCOS, and diffuse endometrial hyperemia was prevalent, as indicated by hysteroscopy. Furthermore, increased BMI, bLH, bT, and AMH levels all contribute to the risk of diffuse endometrial hyperemia.

Pelvic Pain in Reproductive Age: US Findings

Pelvic pain in reproductive age often represents a diagnostic challenge due to the variety of potential causes characterized by overlapping clinical symptoms, including gynecological and other disorders (e.g., entero-colic or urological). It is also necessary to determine if there is a possibility of pregnancy to rule out any related complications, such as ectopic pregnancy. Although ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI) are strongly integrated, the choice of which is the ideal diagnostic tool should be guided both by clinical suspicion (gynecological vs. non-gynecological cause) and by the risk ratio–benefit (ionizing radiation and instrumental costs), too. The didactic objective proposed by this review consists in the diagnosis of the cause and differential of pelvic pain in reproductive age by describing and critically analyzing the US diagnostic clues of the most frequent adnexal, uterine, and vascular causes.

Differential Vaginal Microbiota Profiling in Lactic-Acid-Producing Bacteria between Infertile Women with and without Chronic Endometritis

Purpose: Chronic endometritis (CE) is an infectious and inflammatory disorder associated with infertility of unknown etiology, repeated implantation failure, and recurrent pregnancy loss. In the current clinical practice, intrauterine interventions such as endometrial biopsy/histopathologic examinations and/or hysteroscopy are required for the diagnosis of CE. In this study, we analyzed the microbiota in vaginal secretions (VS) as a potential prediction tool for CE in infertile women. Methods: Using next-generation sequencing analysis, we compared the VS and endometrial fluid (EF) microbiota in infertile women with (n = 20) or without CE (n = 103). Results: The detection rate of Streptococcus and Enterococcus as well as the bacterial abundance of Atopobium and Bifidobacterium in the VS microbiota was significantly lower in the CE group than in the non-CE group. Meanwhile, the detection rate and bacterial abundance of Lactobacillus in the EF and VS microbiota were at similar levels between the two groups. Conclusion: These findings suggest that VS microbiota in infertile women with CE is characterized by the reduction in Bifidobacterium and lactic-acid-producing bacteria other than Lactobacillus. Our results hold promise for the prediction of CE, not by somewhat interventional intrauterine procedures, but by less invasive VS sampling. TRIAL REGISTRATION NUMBER: UMIN000029449 (registration date 6 October 2017).

Sonoelastography evaluation in the diagnosis of endometrial pathology combined with chronic endometritis in infertile women

Endometrial pathology, including hyperplastic processes in the structure of reproductive disorders, occupies one of the leading places along with inflammatory diseases of the pelvic organs, contributing to infertility in 80% of cases and irregular menstrual cycle in 40-43%. This study aims to optimize the diagnostic algorithm in patients with endometrial hyperplasia combined with chronic endometritis and determine qualitative indicators of compression sonoelastography in patients with endometrial pathology and infertility. A comprehensive clinical and laboratory examination of 90 infertile patients aged 25 to 45 years with endometrial hyperplasia combined with chronic inflammation, retention cysts, and benign ovarian tumors was carried out. The results of clinical-laboratory and complex ultrasound examination with compression sonoelastography were compared with the data of pathomorphological and immunohistochemical studies. A high percentage of pelvic inflammatory disease (55.0%), benign lesions of the cervix (67.5%), hyperplastic processes of the myometrium (37.5%), an increasing number of polyps by 2.9 times, leiomyomas and adenomyosis - by 2.3 times (p<0.05) was established. In the case of a combination of endometrial hyperplasia and ovarian cysts, a high percentage of comorbidity of gynecological pathology is verified (37.8%), and the use of compression sonoelastography allows to establish class II and class III elastograms in 91.1% of cases which characterize benign endometrial lesions, reduce the number of false-positive results in 95.6% of cases, correctly interpret the nature of pathological changes and increase the sensitivity of ultrasound techniques.

Emerging trends and frontier research on recurrent implantation failure: a bibliometric analysis

Background

Recurrent implantation failure (RIF) has been recognized to be a major obstacle to the successful application of artificial reproduction technologies. In this study, the trends in RIF research were examined through a bibliometric analysis evaluating relevant literature quantitatively and qualitatively.

Methods

A total of 1,764 publications from 2000 to 2020 were downloaded from the Web of Science Core Collection (WoSCC). Relevant articles were searched using the term "recurrent implantation failure" and other synonyms of this term. Using Excel 2013, CiteSpace V, and VOSviewer 1.6.10 software, data extracted from the literature, including countries/regions, institutions, journals, keywords, and trends, were analyzed. Next, a clustered network was constructed based on 46,718 references cited by the 1,764 publications to determine the top 10 cocited articles.

Results

The annual number of publications on RIF progressively increased over time. The highest number of publications were from the United States. Analysis of the cocited reference cluster showed that "endometrial injury", "platelet-rich plasma", "chronic endometritis" and "extracellular vesicles" were the hotspots in RIF research. Burst detection analysis of the top keywords showed that "hysteroscopy" and "improvement" are emerging research foci.

Conclusions

This study clarifies the current research status and evolution of research in the field of RIF. New therapeutic interventions designed to improve pregnancy outcomes are the focus of current research and are expected to dominate future research in the field of RIF.

Differences in microbial profile of endometrial fluid and tissue samples in women with in vitro fertilization failure are driven by Lactobacillus abundance

INTRODUCTION

The endometrial microbiota has been linked to several gynecological disorders, including infertility. It has been shown that the microbial profile of endometrium could have a role in fertilization and pregnancy outcomes. In this study we aim to assess the microbial community of endometrial tissue (ET) and endometrial fluid (EF) samples in women receiving in vitro fertilization (IVF) treatment. We also search for possible associations between chronic endometritis (CE) and endometrial microbiota.

MATERIAL AND METHODS

This was a cohort study involving 25 women aged between 28 and 42 years with both primary and secondary infertility and with at least one IVF failure. The ET and EF sample collection was carried out between September 2016 and November 2018. Each of the participants provided two types of samples-tissue and fluid samples (50 samples in total). A 16S rRNA sequencing was performed on both of the sample types for microbial profile evaluation. CE was diagnosed based on a CD138 immunohistochemistry where CE diagnosis was confirmed in the presence of one or more plasma cells. Microbial profiles of women with and without CE were compared in both sample types separately.

RESULTS

We report no differences in the microbial composition and alpha diversity (p_Observed  = 0.07, p_Shannon  = 0.65, p_{Inverse Simpson}  = 0.59) between the EF and ET samples of IVF patients. We show that the abundance of the genus Lactobacillus influences the variation in microbial beta diversity between and fluid samples (r²  = 0.34; false discovery rate [FDR] <9.9 × 10^-5 ). We report that 32% (8/25) of the participants had differences in Lactobacillus dominance in the paired samples and these samples also present a different microbial diversity (p_Shannon  = 0.06, FDR_{weighted UniFrac}  = 0.01). These results suggest that the microbial differences between ET and fluid samples are driven by the abundance of genus Lactobacillus. The microbiome of CE and without CE (ie non-CE) women in our sample set of IVF patients was similar.

CONCLUSIONS

Our findings show that genus Lactobacillus dominance is an important factor influencing the microbial composition of ET and fluid samples.

Upstream stimulatory factor 2 (USF2) induced upregulation of triggering receptor expressed on myeloid cells 1 (TREM1) promotes endometritis by regulating toll-like receptor (TLR) 2/4-nuclear factor-kappaB (NF-κB) signaling pathway

Triggering receptor expressed on myeloid cells 1 (TREM1) participates in the development of endometritis. This study aims at identifying the effects and interaction of TREM1 and upstream stimulatory factor 2 (USF2) in endometritis by using a model of lipopolysaccharide (LPS)-induced human endometrial epithelial cells (HEnEpCs). ELISA was performed to determine the levels of interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF-α) after LPS stimulation. TREM1 and USF2 expression was examined with RT-qPCR and Western blot. The JASPAR database was employed to predict the binding site between USF2 and TREM1, which was confirmed by luciferase reporter and chromatin immunoprecipitation assays. After TREM1 overexpression, IL-6, IL-1β, and TNF-α expression was detected by ELISA. Next, the binding of TREM1 to toll-like receptor (TLR) 2/4 was examined with co-immunoprecipitation. Then, proteins in TLR2/4-nuclear factor-kappaB (NF-κB) signaling in HEnEpCs under LPS condition were assessed by Western blot or immunofluorescence before and after TREM1 knockdown. Finally, TLR2 or TLR4 was silenced to explore whether intervene TLR2/4-NF-κB signaling pathway could rescue TREM1-overexpression-induced inflammation in LPS-induced HEnEpCs. Results revealed that upregulated TREM1 was observed in LPS-challenged HEnEpCs. Next, USF2 was found to have transcriptionally active TREM1 expression. Additionally, USF2 knockdown decreased the levels of IL-6, IL-1β, and TNF-α, whereas this effect was rescued after TREM1 overexpression. Besides, TREM1 could bind to TLR2/4 to regulate NF-κB signaling. Moreover, the intervention of TLR2/4-NF-κB signaling pathway rescued TREM1-overexpression-induced inflammation in LPS-stimulated HEnEpCs. Collectively, USF2 promotes endometritis by upregulating TREM1, thereby activating TLR2/4-NF-κB pathway.

A Novel Approach to Minimising Acute Equine Endometritis That May Help to Prevent the Development of the Chronic State

One of the most commonly encountered challenges in equine breeding is endometritis, which can be difficult to resolve and causes considerable economic losses to the industry. It is a multifactorial condition, developing as an exaggerated form of the normal physiological response to breeding. Seminal plasma proteins, spermatozoa, bacteria and debris initiate an inflammatory response; the resulting fluid and neutrophils are then cleared from the uterus along with the debris. However, in some mares, the response is prolonged or exaggerated, with much fluid formation and neutrophil infiltration leading to acute endometritis. A bacterial cause has been implicated, although in some cases no pathogenic organisms can be isolated on culture. It has been postulated that any one of a variety of bacteria could be involved, or dysbiosis of the uterine microbiome could be responsible. Repeated episodes of acute endometritis may lead to the pathology associated with chronic endometritis, with mucociliary dysfunction, vascular degeneration and plasma cell infiltration. This review examines the information that is currently available about equine endometritis, particularly about the role of the inseminate in the uterus, and its current treatment. There are some promising lines of research into treatment or prevention that may help to resolve the issue.

Combined Intestinal Metabolomics and Microbiota Analysis for Acute Endometritis Induced by Lipopolysaccharide in Mice

Endometritis is generally caused by bacterial infections, including both acute and chronic infections. In the past few decades, accumulated evidence showed that the occurrence of diseases might be related to gut microbiota. The progression of diseases is previously known to change the composition and diversity of intestinal microbiota. Additionally, it also causes corresponding changes in metabolites, primarily by affecting the physiological processes of microbiota. However, the effects of acute endometritis on intestinal microbiota and its metabolism remain unknown. Thus, the present study aimed to assess the effects of acute endometritis on intestinal microbes and their metabolites. Briefly, endometritis was induced in 30 specific pathogen-free (SPF) BALB/c female mice via intrauterine administration of lipopolysaccharide (LPS) after anesthesia. Following this, 16S rRNA gene sequencing and liquid chromatogram-mass spectrometry (LC-MS) were performed. At the genus level, the relative abundance of Klebsiella, Lachnoclostridium_5, and Citrobacter was found to be greater in the LPS group than in the control group. Importantly, the control group exhibited a higher ratio of Christensenellaceae_R−7_group and Parasutterella. Furthermore, intestinal metabolomics analysis in mice showed that acute endometritis altered the concentration of intestinal metabolites and affected biological oxidation, energy metabolism, and biosynthesis of primary bile acids. The correlation analysis between microbial diversity and metabolome provided a basis for a comprehensive understanding of the composition and function of the microbial community. Altogether, the findings of this study would be helpful in the prevention and treatment of acute endometritis in the future.

Endometrial microbiota composition is associated with reproductive outcome in infertile patients

BACKGROUND

Previous evidence indicates associations between the female reproductive tract microbiome composition and reproductive outcome in infertile patients undergoing assisted reproduction. We aimed to determine whether the endometrial microbiota composition is associated with reproductive outcomes of live birth, biochemical pregnancy, clinical miscarriage or no pregnancy.

METHODS

Here, we present a multicentre prospective observational study using 16S rRNA gene sequencing to analyse endometrial fluid and biopsy samples before embryo transfer in a cohort of 342 infertile patients asymptomatic for infection undergoing assisted reproductive treatments.

RESULTS

A dysbiotic endometrial microbiota profile composed of Atopobium, Bifidobacterium, Chryseobacterium, Gardnerella, Haemophilus, Klebsiella, Neisseria, Staphylococcus and Streptococcus was associated with unsuccessful outcomes. In contrast, Lactobacillus was consistently enriched in patients with live birth outcomes.

CONCLUSIONS

Our findings indicate that endometrial microbiota composition before embryo transfer is a useful biomarker to predict reproductive outcome, offering an opportunity to further improve diagnosis and treatment strategies. Video Abstract.

MUM-1 immunohistochemistry has high accuracy and reliability in the diagnosis of chronic endometritis: a multi-centre comparative study with CD-138 immunostaining

PURPOSE

The current gold standard for chronic endometritis (CE) diagnosis is immunohistochemistry (IHC) for CD-138. However, IHC for CD-138 is not exempt from diagnostic limitations. The aim of our study was to evaluate the reliability and accuracy of MUM-1 IHC, as compared with CD-138.

METHODS

This is a multi-centre, retrospective, observational study, which included three tertiary hysteroscopic centres in university teaching hospitals. One hundred ninety-three consecutive women of reproductive age were referred to our hysteroscopy services due to infertility, recurrent miscarriage, abnormal uterine bleeding, endometrial polyps or myomas. All women underwent hysteroscopy plus endometrial biopsy. Endometrial samples were analysed through histology, CD138 and MUM-1 IHC. The primary outcome was to evaluate the diagnostic accuracy of MUM-1 IHC for CE, as compared with CD-138 IHC.

RESULTS

Sensitivity and specificity of CD-138 and MUM-1 IHC were respectively 89.13%, 79.59% versus 93.48% and 85.03%. The overall diagnostic accuracy of MUM-1 and CD-138 IHC were similar (AUC = 0.893 vs AUC = 0.844). The intercorrelation coefficient for single measurements was high between the two techniques (ICC = 0.831, 0.761-0.881 95%CI). However, among CE positive women, MUM-1 allowed the identification of higher number of plasma cells/hpf than CD-138 (6.50 [SD 4.80] vs 5.05 [SD 3.37]; p = 0.017). Additionally, MUM-1 showed a higher inter-observer agreement as compared to CD-138.

CONCLUSION

IHC for MUM-1 and CD-138 showed a similar accuracy for detecting endometrial stromal plasma cells. Notably, MUM-1 showed higher reliability in the paired comparison of the individual samples than CD-138. Thus, MUM-1 may represent a novel, promising add-on technique for the diagnosis of CE.

Transcriptomic analysis shows that surgical treatment is likely to influence the endometrial receptivity of patients with stage III/IV endometriosis

BACKGROUND

Endometriosis negatively affects fertility, and it is a common disease in assisted reproductive practice. Surgical removal of endometriotic lesions is widely carried out to relieve symptoms and promote fertility. But it is not intensively investigated what changes in the secretory eutopic endometrium of patients with endometriosis after surgery.

METHODS

Eighteen patients with stage III/IV endometriosis were included in the study, and they were divided into the untreated group and the treated group (6 vs. 12). Basic clinical data were compared, and transcriptomic data of the secretory eutopic endometrium were analyzed with DESeq2, Cytoscape, ClueGO, CluePedia, and Gene Set Enrichment Analysis (GSEA). CIBERSORT was used to calculate the relative abundance of 22 immune cells in the samples.

RESULTS

We determined 346 differentially expressed genes (DEGs) using DESeq2. These DEGs were used to enrich seven Gene Ontology terms including three associated with immune processes and one correlated to prostaglandin using ClueGO and CluePedia. GSEA enriched 28 Gene Ontology terms in the treated group mainly associated with immune and blood pressure regulation process. Compared to the untreated group, the relative abundance of resting CD4+ memory T cells [0.218 (0.069, 0.334) vs. 0.332 (0.181, 0.429), P = 0.022] and the even less abundant memory B cells [0.001 (0.000, 0.083) vs. 0.033 (0.007, 0.057), P = 0.049] are significantly decreased in the treated group.

CONCLUSION

Surgical treatment of stage III/IV endometriosis influences some genes and biological processes related to endometrial receptivity, but more evidence is needed.

The Endometrial Microbiome and Its Impact on Human Conception

Changes in the female genital tract microbiome are consistently correlated to gynecological and obstetrical pathologies, and tract dysbiosis can impact reproductive outcomes during fertility treatment. Nonetheless, a consensus regarding the physiological microbiome core inside the uterine cavity has not been reached due to a myriad of study limitations, such as sample size and experimental design variations, and the influence of endometrial bacterial communities on human reproduction remains debated. Understanding the healthy endometrial microbiota and how changes in its composition affect fertility would potentially allow personalized treatment through microbiome management during assisted reproductive therapies, ultimately leading to improvement of clinical outcomes. Here, we review current knowledge regarding the uterine microbiota and how it relates to human conception.

Elucidation of the anti-inflammatory mechanism of Er Miao San by integrative approach of network pharmacology and experimental verification

Traditional Chinese medicine (TCM) has been long time used in China and gains ever-increasing worldwide acceptance. Er Miao San (EMS), a TCM formula, has been extensively used to treat inflammatory diseases, while its bioactive components and therapeutic mechanisms remain unclear. In this study, we conducted an integrative approach of network pharmacology and experimental study to elucidate the underlying mechanisms of EMS in treating human rheumatoid arthritis (RA) and other inflammatory conditions. Quercetin, wogonin and rutaecarpine were probably the main active compounds of EMS in RA treatment as they affected the most RA-related targets, and TNF-α, IL-6 and IL-1β were considered to be the core target proteins. The main compounds in EMS bound to these core proteins, which was further confirmed by molecular docking and bio-layer interferometry (BLI) analysis. Moreover, the potential molecular mechanisms of EMS predicted from network pharmacology analysis, were validated in vivo and in vitro experiments. EMS was found to inhibit the production of NO, TNF-α and IL-6 in lipopolysaccharide (LPS)-stimulated RAW264.7 cells; reduce xylene-induced mouse ear edema; and decrease the incidence of carrageenan-induced rat paw edema. The carrageenan-induced up-regulation of TNF-α, IL-6 and IL-1β mRNA expression in rat paws was down-regulated by EMS, consistent with the network pharmacology results. This study provides evidence that EMS plays a critical role in anti-inflammation via suppressing inflammatory cytokines, indicating that EMS is a candidate herbal drug for further investigation in treating inflammatory and arthritic conditions.

Hysteroscopic findings in chronic endometritis

Chronic endometritis (CE) is a subtle pathology. Despite being difficult to detect and probably underdiagnosed, it has great clinical relevance, representing as it does a reversible cause of infertility. Nowadays, histological examination with identification of endometrial stromal plasma cells is considered the gold standard for diagnosis. Diagnostic difficulties persist, however, as a result of the technical limitations of this method and the lack of standardized histological diagnostic criteria. Hysteroscopy has been proposed as an aid for CE diagnosis. The method works by detecting signs of inflammation (focal or diffuse hyperemia, stromal edema, presence of micropolyps and the typical strawberry aspect) on the endometrial surface. Yet, the jury is still out on how reliable this technique is. Hysteroscopy displays a high sensitivity (over 86% and up to 100%) and high negative predictive value (over 92% and up to 100%) in the diagnosis of CE, and it should probably be performed routinely in the assessment of patients with unexplained infertility, repeated implantation failure and repeated pregnancy loss; however, since values in the literature regarding specificity are conflicting, in cases of suspected CE, hysteroscopy may be combined with histological examination, which remains the gold standard to confirm CE. Considering that histopathological evaluation probably underdiagnoses CE, and that hysteroscopy tends to overdiagnose, further studies are needed to determine which technique (or combination of techniques) has greater value for patients.

Association between Endometrial Polyps and Chronic Endometritis: Is It Time for a Paradigm Shift in the Pathophysiology of Endometrial Polyps in Pre-Menopausal Women? Results of a Systematic Review and Meta-Analysis

BACKGROUND

Chronic endometritis (CE) and endometrial polyps (EPs) are common conditions in reproductive age women. CE is an infectious disorder of the endometrium characterized by signs of chronic inflammation at hysteroscopic and histological analyses. EPs are abnormal endometrial growths containing glands, stroma and blood vessels projecting from the lining of the uterus. During the last years, different authors have investigated the correlation between CE and EPs, with controversial results. The aim of this study was to summarize available evidence on the potential correlation between CE and EPs.

DESIGN

Systematic literature review and meta-analysis.

METHODS

Observational-studies were identified by searching electronic databases from their inception to September 2021. Only studies on pre-menopausal women were included. Statistical analysis was performed using MedCalc 16.4.3 (Ostend, Belgium) and Review Manager version 5.3 (Nordic Cochrane Centre, Cochrane Collaboration). The summary measures were reported as pooled proportion or odds ratio (OR) with 95% confidence interval (CI). The primary outcome was to evaluate the prevalence of CE in women with EPs. The secondary outcome was to determine the prevalence of CD-138-positive EPs among EPs. Tertiary outcomes were to compare the prevalence of CE in women with EPs versus women with a non-polypoid endometrium and to compare the prevalence of CE in women with a single EP versus women with multiple EPs.

RESULTS

Eight observational studies (n = 3225 patients) were included in quantitative synthesis. Pooled prevalence of CE among women with EPs was 51.35% (95% CI, 27.24-75.13%). Pooled proportion of CD-138-positive EPs among EPs was 70.73% (95% CI, 55.73-83.68%). Women with EPs showed higher prevalence of CE compared to women without EPs (OR 3.07, 95% CI 1.59-5.95). Women with ≥3 EPs had higher prevalence of CE then women with a single EP (OR 3.43, 95% CI 1.83-6.46).

CONCLUSIONS

In pre-menopausal women, CE and EPs may have a dependent relationship and may represent two consequent steps of a common pathological process.

Honokiol inhibits endoplasmic reticulum stress-associated lipopolysaccharide-induced inflammation and apoptosis in bovine endometrial epithelial cells

Honokiol (HKL) has been previously reported to exert anti-inflammatory effects in numerous diseases. However, the role of HKL in endometritis remains unclear. The present study aimed to explore and elucidate the role of HKL in a lipopolysaccharide (LPS)-induced in vitro model of endometritis. Bovine endometrial epithelial cells (bEECs) were pre-treated with HKL at doses of 1, 10 and 20 µM, followed by 1 µg/ml LPS. MTT assay was then used to detect cell viability. ELISA was utilized to measure the levels of the proinflammatory cytokines TNF-α, IL-1β and IL-6 in bEECs culture supernatants. Reverse transcription-quantitative PCR was further performed to examine the mRNA expression levels of these cytokines. Cell apoptosis was observed by TUNEL staining and the levels of Bcl-2, Bax, cleaved caspase 3 and cleaved caspase 9 were assayed by western blotting. Western blotting was also performed to detect the expression levels of endoplasmic reticulum (ER) stress-related proteins activating transcription factor 6, CCAAT-enhancer-binding protein homologous protein, inositol-requiring enzyme 1 and cleaved caspase 12 in bEECs. LPS treatment reduced cell viability and HKL treatment improved the viability of bEECs after LPS treatment. The LPS-induced inflammatory response and apoptosis in bEECs were also inhibited by HKL treatment. Additionally, the increased expression of ER stress-related proteins induced by LPS was reversed by HKL treatment. Following stimulation with the ER stress inducer tunicamycin, it was revealed that HKL attenuated ER stress and inhibited LPS-induced inflammatory response and apoptosis in bEECs. In summary, HKL inhibited ER stress associated with LPS-induced inflammation and apoptosis in bEECs, providing evidence that HKL can serve to be a novel agent for the treatment of endometritis.

Therapeutic potential of curcumin in endometrial disorders: Current status and future perspectives

Endometrial disorders collectively encompass a broad spectrum of pathologies, including but not limited to endometriosis, endometrial cancer and endometritis. The current therapeutic management of these diseases is associated with several limitations. This has prompted interest in the use of plant-based bioactive compounds as alternative strategies to achieve high therapeutic efficacy and avoid adverse effects. In this context, curcumin, a polyphenol abundantly present in turmeric, is gaining increasing attention for its therapeutic potential to restore homeostasis in endometrial dysfunctionality. We comprehensively review the multifaceted role of curcumin, discussing mechanistic insights in various endometrial pathologies. We also provide an in-depth analysis of the concerns and challenges associated with the role of curcumin in endometrial research and outline a road map for future investigations.

Effect of Inonotus obliquus polysaccharide on composition of the intestinal flora in mice with acute endometritis

Inonotus obliquus Polysaccharide (IOP) is a large molecule extracted from Inonotus obliqus, a medicinal fungus, which has a wide range of biological activities and has been shown to be associated with inflammation. The purpose of this study is to investigate whether IOP can help to reduce acute endometritis by regulating intestinal flora. We observed pathological changes in mice with endometritis following treatment with IOP and evaluated changes in the levels of interleukin-6 (IL-6), interleukin-1β (IL-1β) and tumor necrosis factor α (TNF-α), and further studied the effects of IOP on the intestinal flora of endometritis mice using 16S rRNA high-throughput sequencing. The results showed that IOP improved the condition of uterine tissues and reduced the release of pro-inflammatory cytokines. Meanwhile, the 16S rRNA sequencing results showed that IOP could regulate the changes in intestinal microflora at the level of genera, possibly by changing the relative abundance of some genera.

Occurrence of chronic endometritis in different types of human adenomyosis

Purpose

Human adenomyosis has an adverse effect on female fertility. Exact mechanistic basis is still unclear. We investigated the occurrence of chronic endometritis (CE) in different types of human adenomyosis.

Methods

This is a prospective non‐randomized observational study enrolling patients with focal (n = 30), diffuse (n = 26), intrinsic (n = 23), and extrinsic (n = 10) adenomyosis. Endometrial biopsy samples were collected from hysterectomy specimens. Immunohistochemical analysis was performed using antibody against CD68 (Mφ marker) with biopsy samples of intrinsic/extrinsic adenomyosis and CD138 (Syndecan‐1), a marker of plasma cells, in all biopsy samples.

Results

In GnRHa‐untreated groups, a higher trend in the occurrence of CE, as characterized by infiltration of ≥1 plasma cells in endometrial stroma, was found in women with focal (58.8%, p = 0.0849) and diffuse adenomyosis (60.0%, p = 0.0841) comparing to control women (10.0%). In women with focal adenomyosis, ipsilateral side showed a significantly higher occurrence of CE (58.8%) than on the contralateral side (11.7%) (p = 0.043). Tissue infiltration of macrophages in endometria was significantly higher in intrinsic than in extrinsic adenomyosis (p = 0.03) without showing any significant difference in the occurrence of CE between these two variants of adenomyosis.

Conclusion

A variable occurrence of CE in different types of adenomyosis may be involved in adverse reproductive outcome.

Chronic endometritis: A prevalent yet poorly understood entity

OBJECTIVE

To examine the prevalent understanding of and management approaches to chronic endometritis among obstetricians/gynecologists.

METHODS

In a cross-sectional observational study, 262 members of national and international professional obstetrician/gynecologist societies were surveyed via anonymous electronic survey that investigated knowledge of the pathophysiology, diagnostic criteria, clinical implications, and treatment strategies for chronic endometritis. Statistical analyses of results were performed using Fisher's exact tests, chi square tests and odds ratios with 95% confidence intervals. A two-sided P < 0.05 was deemed statistically significant.

RESULTS

Responses identified a concerning spectrum of deficiencies in the understanding of the pathophysiology of chronic endometritis, in awareness of clinical presentation of chronic endometritis, and in the understanding of methodology/ies that allow diagnosis of chronic endometritis. Heterogeneities in management approaches to chronic endometritis were apparent.

CONCLUSION

Our findings underscore a need for targeted efforts to gain clarity on chronic endometritis and to establish evidence-based consensus for good clinical practice. In the absence of a clear understanding of chronic endometritis diagnosis, we posit that the prevalent inconsistencies are likely inflicting unquantified and underappreciated burdens on patients and healthcare systems. We propose consideration for a task force to examine existing literature and create standards for good practice for a prevalent condition.

Endometrial polyps with increased plasma cells are associated with chronic endometritis in infertility patients: Hysteroscopic findings and post-polypectomy pregnancy rates

PURPOSE

The relationship between endometrial polyps (EPs), chronic endometritis (CE), hysteroscopic findings, and antimicrobial in infertility patients was determined.

METHODS

We retrospectively enrolled 115 infertility patients with suspected EPs who underwent office hysteroscopy. Patients were divided into 3 groups: 38 with increased plasma cells in EPs (group 1); 31 without increased plasma cells in EPs (group 2); and 46 without EPs (group 3). The 3 groups underwent hysteroscopy with or without polypectomies, and immediately thereafter, an endometrial aspiration biopsy (EAB) was performed. CE was diagnosed based on plasma cell infiltration in the non-polypoid endometrium obtained by EAB.

RESULTS

The percentage of CE was 68.4%, 32.2%, and 28.3% in groups 1, 2, and 3, respectively. CE was more frequent in group 1 than group 2 or 3 (P = .01 and P = .002, respectively). The number of polyps was higher in group 1 than group 2. After adjustment for age and assisted reproductive technology, antibiotic therapy was not associated with pregnancy (adjusted odds ratio, 0.44; 95% confidence interval, 0.05-3.57) in patients with EPs and CE.

CONCLUSIONS

Group 1 was associated with CE, and hysteroscopic findings were different from group 2. Antibiotic therapy after polypectomy for EPs with CE may not always be necessary.

The impact of the female genital tract microbiome in women health and reproduction: a review

PURPOSE

The aim of this review is to gather the available research focusing on female genital tract (FGT) microbiome. Research question focuses in decipher which is the role of FGT microbiota in eubiosis, assisted reproduction techniques (ARTs), and gynaecological disorders, and how microbiome could be utilised to improve reproduction outcomes and to treat fertility issues.

METHODS

PubMed was searched for articles in English from January 2004 to April 2021 for "genital tract microbiota and reproduction", "endometrial microbiome", "microbiome and reproduction" and "microbiota and infertility". Manual search of the references within the resulting articles was performed.

RESULTS

Current knowledge confirms predominance of Lactobacillus species, both in vagina and endometrium, whereas higher variability of species is both found in fallopian tubes and ovaries. Microbial signature linked to different disorders such endometriosis, bacterial vaginosis, and gynaecological cancers are described. Broadly, low variability of species and Lactobacillus abundance within the FGT is associated with better reproductive and ART outcomes.

CONCLUSION

Further research regarding FGT microbiome configuration needs to be done in order to establish a more precise link between microbiota and eubiosis or dysbiosis. Detection of bacterial species related with poor reproductive outcomes, infertility or gynaecological diseases could shape new tools for their diagnosis and treatment, as well as resources to assess the pregnancy prognosis based on endometrial microbiota. Data available suggest future research protocols should be standardised, and it needs to include the interplay among microbiome, virome and mycobiome, and the effect of antibiotics or probiotics on the microbiome shifts.

The Effect of Ascorbic Acid on Interleukin-10 and Tumor Necrosis Factor-α Cytokines in Rattus norvegicus with Endometritis

BACKGROUND: Endometritis is a gynecological disease characterized by inflammation of the endometrial glands and stroma. Inflammatory stimuli or tissue injury induce inflammatory pain through the release of cytokines. Ascorbic acid (AA) is a water-soluble Vitamin that plays a role in inhibiting the production of proinflammatory cytokines and increases the expression of anti-inflammatory cytokines. AIM: The purpose of this study was to find out the association between administration of AA and inflammatory cytokines in experimental animals Rattus norvegicus with endometritis. METHODS: The research was conducted using virgin female R. norvegicus laboratory mice weighing 250–300 g and aged 11–12 weeks with an estrus cycle of 5–6 days. Mice with regular oestrous cycles were randomly divided into three groups: group 1 was given 200 L of water orally without Escherichia coli inoculation and represented a negative control. Groups 2 and 3 were inoculated (50 L/rat) E. coli intravaginally, 106 colony-forming unit/mL, Group 2 was not given AA and the other side Group 3 was assigned AA. The interleukin (IL)-10 and tumor necrosis factor (TNF)-α _cytokines examination was carried out by histopathological examination through a biopsy of the endometrial tissue. Hypothesis testing on the data was analyzed by the Kruskal Wallis test using Statistical Package for Social Sciences. RESULTS: Data from the current study revealed that the highest mean value of IL-10 was found in the negative control group (2.5) and the lowest value in the positive control group (1.3). Regarding TNF-α _the highest mean value (2.8) was found in the treatment group and the lowest mean value (2.1) was found in the treatment group. Using the Kruskal Wallis test, IL-10 and TNF-α _showed insignificant results (p = value 0.304 and 0.145 respectively). CONCLUSIONS: The administration of AA did not affect the decrease in TNF-α _or the upregulation of IL-10 as anti-inflammatory cytokines.

Identification of Uterine Microbiota in Infertile Women Receiving in vitro Fertilization With and Without Chronic Endometritis

In vitro fertilization (IVF) is an important assisted reproductive technology in treating infertility, whose failure rate is still high. Studies suggested that uterine microbiota are related to women’s reproductive diseases and persisting intrauterine bacterial infectious conditions, such as chronic endometritis (CE), impairing the pregnant processes. However, the relationship between uterine microbiota and IVF outcomes is still an open question. In the present study, 94 patients diagnosed with infertility were enrolled and were divided into CE (E group, n = 25) and non-CE (NE group, n = 69) groups depending on the hysteroscopy and immunohistochemistry. Subsequently, E (Ep, n = 8 and Enp, n = 17) and NE (NEp, n = 41 and NEnp, n = 28) groups were divided into pregnancy and non-pregnancy groups depending on the IVF outcomes, respectively. The uterine fluids were collected and microbial profiles were examined through the V4 region of 16S rRNA gene high-throughput sequencing. The results demonstrated that patients with CE had significantly lower clinical pregnancy rate compared with the non-CE patients (32 vs. 58.42%, p = 0.0014). The relative abundances of Proteobacteria and Acidobacteria were higher in the non-CE group, whereas high abundances of Actinobacteria and Fusobacteria were observed in the CE group at the phylum level. At the genus level, high relative abundances of Gardnerella were observed in the CE group and non-pregnancy groups, which significantly referred to the negative IVF outcome. In conclusion, CE may be a key factor for the negative outcome after IVF, of which the uterine microbiota plays a pivotal role, and the microbial diversity in uterine may serve as a biomarker to forecast the success of IVF outcome.

CircRNA circFADS2 is Downregulated in Endometritis and its Overexpression Promotes miR-643 Maturation in Human Endometrial Epithelial Cells to Suppress Cell Apoptosis

CircRNA circFADS2 suppresses LPS-induced inflammation, which plays a critical role in endometritis. Our preliminary sequencing analysis revealed a positive correlation between circFADS2 and miR-643, which also play protective roles in LPS-induced inflammation. Therefore, this study was performed to explore the involvement of circFADS2 in endometritis with a focus on its interaction with miR-643. RT-qPCR was performed to analyze the levels circFADS2, mature miR-643, and premature miR-643 in plasma samples from endometritis patients (n = 66) and healthy controls (n = 66). Pearson's correlation coefficient was applied to analyze correlations between these genes. The effect of circFADS2 on miR-643 maturation was analyzed by measuring miR-643 and premature miR-643 levels in circFADS2-overexpressed human endometrial epithelial cell line HEnEpCs. The role of circFADS2 and miR-643 in HEnEpC apoptosis under LPS treatment was analyzed by cell apoptosis assay. CircFADS2 was downregulated in endometritis and was positively correlated with mature miR-643, but not premature miR-643. CircFADS2 overexpression in HEnEpCs increased the level of mature miR-643 but not premature miR-643. Cell apoptosis analysis showed that circFADS2 and miR-643 overexpression protected HEnEpCs from LPS-induced cell apoptosis, and miR-643 inhibition reduced the effect of circFADS2 overexpression. CircFADS2 is downregulated in endometritis, and it overexpression promotes miR-643 maturation in HEnEpCs to suppress cell apoptosis.

Effects of Resveratrol on Receptor Expression and Serum Levels of Estrogen and Progesterone in the Rat Endometritis Model

Endometritis is characterized by inflammation of the endometrial lining that leads to reduced reproductive potential. Restoring the impaired hormonal balance is an important component of endometritis treatment. The purpose of the current study was to evaluate the effects of resveratrol on estrogen and progesterone hormone status in endometritis. Mature female Sprague Dawley rats were used, and endometritis was induced by intrauterine infusion of Escherichia coli. Animals were treated with resveratrol alone or combined with marbofloxacin. Compared to the non-treated endometritis group, resveratrol treatment reduced serum oestradiol levels, increased serum progesterone levels, enhanced estrogen receptor (ER) expression in the uterine stroma, decreased ESR1 gene expression, and raised ESR2 gene expression. Resveratrol administration combined with marbofloxacin also increased ER expression in the uterine gland and progesterone receptor expression in the uterine epithelium. The findings of this study suggest that the actions of resveratrol on progesterone levels and estrogen receptor expression might be responsible for its beneficial effect in rats with endometritis.

Correlation between hysteroscopy findings in patients with hydrosalpinx and chronic endometritis

OBJECTIVE

To evaluate the role of hydrosalpinx in susceptibility to chronic endometritis (CE).

METHODS

This is a retrospective cohort study, which includes 624 patients with hydrosalpinx (group A) and 789 patients without hydrosalpinx (group B) undergoing laparoscopy and hysteroscopy simultaneously. Endometrial morphology was recorded under hysteroscopy. Endometrial biopsy was obtained after hysteroscopy, and immunohistochemical staining for syndecan-1 (CD138) was carried out.

RESULTS

No significantly statistical differences were found between the two groups when comparing the incidence of endometrial hyperemia or endometrial micro-polyps under hysteroscopy (P > 0.05). Hydrosalpinx had a significant impact on the incidence of CE (P < 0.05) (plasma cell count: no plasma cells: odds ratio [OR] 0.71, 95% confidence interval [CI] 0.58-0.88, P = 0.002; ≥1/high-power field [HPF]: OR 1.40, 95% CI 1.14-1.74, P = 0.002; ≥3/HPF: OR 1.50, 95% CI 1.18-1.91, P = 0.001; ≥5/HPF: OR 1.62, 95% CI 1.27-2.21, P < 0.001). There were no significant differences in the comparison of plasma cell count between the unilateral hydrosalpinx group (274 patients) and the bilateral hydrosalpinx group (350 patients) (P > 0.05).

CONCLUSION

The presence of hydrosalpinx increased the incidence of CE. Bilateral hydrosalpinx did not significantly increase the incidence of CE compared with unilateral hydrosalpinx.

Treatment following hysteroscopy and endometrial diagnostic biopsy increases the chance for live birth in women with chronic endometritis

Problem

Repeated implantation failure and recurrent pregnancy loss are associated with chronic endometritis, a persistent endometrial inflammation. Its diagnosis and treatment may increase pregnancy and live birth rates. The aim of this study was to assess the effectiveness of endometrial diagnostic biopsy and subsequent antibiotic treatment in cases of chronic endometritis on reproductive outcomes over a long observation period.

Method of Study

We conducted a historical cohort study (2014–2018) at our University‐based infertility center that included women (n = 108) with repeated implantation failure or recurrent pregnancy loss without known pathologies associated with either condition. Forty‐one women underwent a hysteroscopy only (reference group); the remaining 67 women underwent, in addition to the hysteroscopy, an endometrial diagnostic biopsy with immunohistochemically staining for CD138 to detect plasma cells (biopsy group). If one or more plasma cells were detected, the women were treated with doxycycline 100 mg twice a day orally for 2 weeks. We performed stratified survival analysis (Kaplan‐Meier) and Cox regression.

Results

The biopsy group had higher chances of pregnancy (hazard ratio 2.28; 95% confidence interval 1.23–4.24; p = .009) and of live birth (hazard ratio 2.76; 95% confidence interval 1.30–5.87; p = .008) compared with the reference group. In the sensitivity analysis, repeated implantation failure or recurrent pregnancy loss did not affect the outcome.

Conclusion

Endometrial diagnostic biopsy followed by antibiotic treatment in case of chronic endometritis in women with repeated implantation failure or recurrent pregnancy loss may increase the chances for live birth.

Clinical consequences of defective decidualization

Decidualization is characterized by a series of genetic, metabolic, morphological, biochemical, vascular and immune changes occurring in the endometrial stroma in response to the implanting embryo or even before conception and involves the stromal cells of the endometrium. It is a fundamental reproductive event occurring in mammalian species with hemochorial placentation. A growing body of experimental and clinical evidence strongly suggests that defective or disrupted decidualization contributes to the establishment of an inappropriate maternal-fetal interface. This has relevant clinical consequences, ranging from recurrent implantation failure and recurrent pregnancy loss in early pregnancy to several significant complications of advanced gestation. Moreover, recent evidence indicates that selected diseases of the endometrium, such as chronic endometritis and endometriosis, can have a detrimental impact on the decidualization response in the endometrium and may help explain some aspects of the reduced reproductive outcome associated with these conditions. Further research efforts are needed to fully understand the biomolecular mechanisms ans events underlying an abnormal decidualization response. This will permit the development of new diagnostic and therapeutic strategies aimed to improve the likelihood of achieveing a successful pregnancy.

Effect of Sow Intestinal Flora on the Formation of Endometritis

Endometritis is the main cause of decreased reproductive performance of sows, while one of the most important factors in the etiology of sow endometritis is an aberration of birth canal microbiota. Therefore, people began to pay attention to the microbiota structure and composition of the birth canal of sows with endometritis. Interestingly, we found that the risk of endometritis was increased in the sows with constipation in clinical practice, which may imply that the intestinal flora is related to the occurrence of endometritis. Therefore, understanding the relationship between birth canal microbiota and intestinal microbiota of the host has become exceptionally crucial. In this study, the microbiota of birth canal secretions and fresh feces of four healthy and four endometritis sows were analyzed via sequencing the V3 + V4 region of bacterial 16S ribosomal (rDNA) gene. The results showed a significant difference between endometritis and healthy sows birth canal flora in composition and abundance. Firmicutes (74.36%) and Proteobacteria were the most dominant phyla in birth canal microbiota of healthy sows. However, the majority of beneficial bacteria that belonging to Firmicutes phylum (e.g., Lactobacillus and Enterococcus) declined in endometritis sow. The abundance of Porphyromonas, Clostridium sensu stricto 1, Streptococcus, Fusobacterium, Actinobacillus, and Bacteroides increased significantly in the birth canal microbiota of endometritis sows. Escherichia–Shigella and Bacteroides were the common genera in the birth canal and intestinal flora of endometritis sows. The abundance of Escherichia–Shigella and Bacteroides in the intestines of sows suffering from endometritis were significantly increased than the intestinal microbiota of the healthy sows. We speculated that some intestinal bacteria (such as Escherichia–Shigella and Bacteroides) might be bound up with the onset of sow endometritis based on intestinal microbiota analysis in sows with endometritis and healthy sows. The above results can supply a theoretical basis to research the pathogenesis of endometritis and help others understand the relationship with the microbiota of sow's birth canal and gut.

Determining diagnostic criteria and cause of recurrent implantation failure

PURPOSE OF REVIEW

Recurrent implantation failure (RIF) refers to the absence of implantation after repeated transfer of good embryos into a normal uterus. This review discusses the diagnostic criteria and cause of RIF.

RECENT FINDINGS

Regardless of the advancements in IVF practice, RIF is still a challenge that has to be solved. Exact definition of RIF is lacking today. For the initial evaluation, a rigorous algorithmic evaluation should be compromised with an individualized principle. Factors that might affect the number and quality of the oocyte and sperm cells should be investigated in order to obtain a good-quality embryo. Embryo assessment should be performed under ideal laboratory circumstances. The uterine environment should be carefully evaluated and the embryo should be transferred into the uterus at the most receptive time. Some of the newly introduced diseases and empirical treatment strategies, such as chronic endometritis, vaginal microbiota, immunologic profile and immunomodulator treatments, can be discussed with the couple under the light of adequate evidence-based information.

SUMMARY

New diagnostic and treatment modalities are needed to be introduced, which would be safe, efficient and efficacious after well-designed randomized controlled trials.