Commonalities and Disparities between Endometriosis and Chronic Endometritis: Therapeutic Potential of Novel Antibiotic Treatment Strategy against Ectopic Endometrium

Variation in diagnostic methods, criteria, and treatment for chronic endometritis: A nationwide survey in Japan

AIM

To investigate variation in the diagnosis and treatment of chronic endometritis (CE) at the national level in Japan.

METHODS

We performed a nationwide survey targeting all assisted reproductive technology (ART) facilities across Japan between 2021 and 2022. Diagnostic methods, criteria, and first- and second-line treatment protocols for CE were collected via a questionnaire.

RESULTS

Among 616 ART facilities, 437 responded to the survey (response rate: 70.9%) of which 339 (77.6%) implemented diagnosis and treatment of CE. In the diagnosis of CE, 214 (63.1%) facilities used CD138 immunohistochemical staining of endometrial tissue, while hysteroscopy was the most frequently used as an adjunct diagnostic method (241 facilities, 71.1%). The most frequent cutoff value of CD138-positive cells for diagnosing CE was 3-5 cells/20 high-power fields (50%), but 7.9% (17 facilities) and 5.1% (11 facilities) used cutoff values of 1 and 2 cells, respectively. The most common first- and second-line treatment methods were doxycycline (210 facilities, 61.9%) and ciprofloxacin + metronidazole (164 facilities, 48.0%), respectively.

CONCLUSIONS

There is considerable variation in the number of CD138-positive cells used for diagnosing CE. Establishing unified diagnostic criteria and therapeutic methods for CE is essential to provide standardized medicine for CE at the national level.

Microbiota and Recurrent Pregnancy Loss (RPL); More than a Simple Connection

Recurrent Pregnancy Loss (RPL) affects 1-2% of women, and its triggering factors are unclear. Several studies have shown that the vaginal, endometrial, and gut microbiota may play a role in RPL. A decrease in the quantity of Lactobacillus crispatus in local microbiota has been associated with an increase in local (vaginal and endometrial) inflammatory response and immune cell activation that leads to pregnancy loss. The inflammatory response may be triggered by gram-negative bacteria, lipopolysaccharides (LPS), viral infections, mycosis, or atypia (tumor growth). Bacterial structures and metabolites produced by microbiota could be involved in immune cell modulation and may be responsible for immune cell activation and molecular mimicry. Gut microbiota metabolic products may increase the amount of circulating pro-inflammatory lymphocytes, which, in turn, will migrate into vaginal or endometrial tissues. Local pro-inflammatory Th1 and Th17 subpopulations and a decrease in local Treg and tolerogenic NK cells are accountable for the increase in pregnancy loss. Local microbiota may modulate the local inflammatory response, increasing pregnancy success. Analyzing local and gut microbiota may be necessary to characterize some RPL patients. Although oral supplementation of probiotics has not been shown to modify vaginal or endometrial microbiota, the metabolites produced by it may benefit patients. Lactobacillus crispatus transplantation into the vagina may enhance the required immune tolerogenic response to achieve a normal pregnancy. The effect of hormone stimulation and progesterone to maintain early pregnancy on microbiota has not been adequately studied, and more research is needed in this area. Well-designed clinical trials are required to ascertain the benefit of microbiota modulation in RPL.

Individuality and generality of intratumoral microbiome in the three most prevalent gynecological malignancies: an observational study

Growing evidence have indicated the crucial role of intratumor microbiome in a variety of solid tumor. However, the intratumoral microbiome in gynecological malignancies is largely unknown. In the present study, a total of 90 Han patients, including 30 patients with cancer in cervix, ovary, and endometrium each were enrolled, the composition of intratumoral microbiome was assessed by 16S rDNA amplicon high throughput sequencing. We found that the diversity and metabolic potential of intratumoral microbiome in all three cancer types were very similar. Furthermore, all three cancer types shared a few taxa that collectively take up high relative abundance and positive rate, including Pseudomonas sp., Comamonadaceae gen. sp., Bradyrhizobium sp., Saccharomonospora sp., Cutibacterium acnes, Rubrobacter sp., Dialister micraerophilus, and Escherichia coli. Additionally, Haemophilus parainfluenzae and Paracoccus sp. in cervical cancer, Pelomonas sp. in ovarian cancer, and Enterococcus faecalis in endometrial cancer were identified by LDA to be a representative bacterial strain. In addition, in cervical cancer patients, alpha-fetoprotein (AFP) (correlation coefficient = -0.3714) was negatively correlated (r = 0.4, 95% CI: 0.03 to 0.7) with Rubrobacter sp. and CA199 (correlation coefficient = 0.3955) was positively associated (r = 0.4, 95% CI: 0.03 to 0.7) with Saccharomonospora sp.. In ovarian cancer patients, CA125 (correlation coefficient = -0.4451) was negatively correlated (r = -0.4, 95% CI: -0.7 to -0.09) with Porphyromonas sp.. In endometrial cancer patients, CEA (correlation coefficient = -0.3868) was negatively correlated (r = -0.4, 95% CI: -0.7 to -0.02) with Cutibacterium acnes. This study promoted our understanding of the intratumoral microbiome in gynecological malignancies.IMPORTANCEIn this study, we found the compositional spectrum of tumor microbes among gynecological malignancies were largely similar by sharing a few taxa and differentiated by substantial species owned uniquely. Certain species, mostly unreported, were identified to be associated with clinical characteristics. This study prompted our understanding of gynecological malignancies and offered evidence for tumor microbes affecting tumor biology among cancers in the female reproductive system.

Bridging the Diagnostic Gap between Histopathologic and Hysteroscopic Chronic Endometritis with Deep Learning Models

Chronic endometritis (CE) is an inflammatory pathologic condition of the uterine mucosa characterized by unusual infiltration of CD138(+) endometrial stromal plasmacytes (ESPCs). CE is often identified in infertile women with unexplained etiology, tubal factors, endometriosis, repeated implantation failure, and recurrent pregnancy loss. Diagnosis of CE has traditionally relied on endometrial biopsy and histopathologic/immunohistochemistrical detection of ESPCs. Endometrial biopsy, however, is a somewhat painful procedure for the subjects and does not allow us to grasp the whole picture of this mucosal tissue. Meanwhile, fluid hysteroscopy has been recently adopted as a less-invasive diagnostic modality for CE. We launched the ARCHIPELAGO (ARChival Hysteroscopic Image-based Prediction for histopathologic chronic Endometritis in infertile women using deep LeArninG mOdel) study to construct the hysteroscopic CE finding-based prediction tools for histopathologic CE. The development of these deep learning-based novel models and computer-aided detection/diagnosis systems potentially benefits infertile women suffering from this elusive disease.

Construction of deep learning-based convolutional neural network model for automatic detection of fluid hysteroscopic endometrial micropolyps in infertile women with chronic endometritis

OBJECTIVE(S)

Chronic endometritis (CE) is a localized mucosal inflammatory disorder associated with female infertility of unknown etiology, endometriosis, tubal factors, repeated implantation failure, and recurrent pregnancy loss, along with atypical uterine bleeding and iron deficiency anemia. Diagnosis of CE has traditionally relied on endometrial biopsy and detection of CD138(+) endometrial stromal plasmacytes. To develop a less invasive diagnostic system for CE, we aimed to construct a deep learning-based convolutional neural network (CNN) model for the automatic detection of endometrial micropolyps (EMiP), a fluid hysteroscopy (F-HSC) finding recognized as tiny protrusive lesions that are closely related to this disease.

STUDY DESIGN

This is an in silico study using archival images of F-HSC performed at an infertility center in a private clinic. A total of 244 infertile women undergoing F-HSC on the days 6-12 of the menstrual cycle between April 2019 and December 2021 with histopathologically-confirmed CE with the aid of immunohistochemistry for CD138 were utilized.

RESULTS

The archival F-HSC images of 208 women (78 with EMiP and 130 without EMiP) who met the inclusion criteria were finally subjected to analysis. Following preprocessing of the images, half a set was input into a CNN architecture for training, whereas the remaining images were utilized as the test set to evaluate the performance of the model, which was compared with that of the experienced gynecologists. The sensitivity, specificity, accuracy, precision, and F1-score of the CNN model-aided diagnosis were 93.6 %, 92.3 %, 92.8 %, 88.0 %, and 0.907, respectively. The area under the receiver operating characteristic curves of the CNN model-aided diagnosis (0.930) was at a similar level (p > .05) to the value of conventional diagnosis by three experienced gynecologists (0.927, 0.948, and 0.906).

CONCLUSION

These findings indicate that our deep learning-based CNN is capable of recognizing EMiP in F-HSC images and holds promise for further development of the computer-aided diagnostic system for CE.

Bacteriophages, gut bacteria, and microbial pathways interplay in cardiometabolic health

Cardiometabolic diseases are leading causes of mortality in Western countries. Well-established risk factors include host genetics, lifestyle, diet, and the gut microbiome. Moreover, gut bacterial communities and their activities can be altered by bacteriophages (also known simply as phages), bacteria-infecting viruses, making these biological entities key regulators of human cardiometabolic health. The manipulation of bacterial populations by phages enables the possibility of using phages in the treatment of cardiometabolic diseases through phage therapy and fecal viral transplants. First, however, a deeper understanding of the role of the phageome in cardiometabolic diseases is required. In this review, we first introduce the phageome as a component of the gut microbiome and discuss fecal viral transplants and phage therapy in relation to cardiometabolic diseases. We then summarize the current state of phageome research in cardiometabolic diseases and propose how the phageome might indirectly influence cardiometabolic health through gut bacteria and their metabolites.

Emerging bacterial factors for understanding pathogenesis of endometriosis

The pathogenesis of endometriosis is a complex process, and recent research has introduced novel hypotheses in this field. This review summarizes recent studies on the pathogenesis of endometriosis. We focused on several classical hypotheses, as well as their interactions with the microenvironment of hormonal dependence and immunosuppression. Furthermore, we highlighted the emergence of bacterial factors associated with endometriosis. Recent advances in next-generation sequencing (NGS) have revealed the presence and detailed distribution of these bacteria as well as the involvement of specific bacteria in pathogenesis. These factors alter the microenvironment in the early stages of endometriosis development, leading to lesion formation. Understanding the mechanisms underlying the early development of endometriosis from a new perspective would be helpful for the development of novel therapeutic agents for endometriosis.

Translocation of vaginal and cervical low-abundance non-Lactobacillus bacteria notably associate with endometriosis: A pilot study

The etiology remains to be understood for endometriosis (EMS) which affected health negatively for 10% of reproductive-age women globally. Emerging studies found the associations of EMS with genital microbiota dysbiosis. However, the role of vaginal and cervical microbiota is not fully understood for Chinese women. This study recruited forty Chinese women (21 healthy women and 19 EMS patients) to analyze vaginal and cervical microbiota using 16S rRNA amplicon sequencing method. For both sites, there were no significant differences for distribution of microbial samples between control and EMS group, which was concordant with dominated Lactobacillus in both groups. In contrast, we observed accumulation of several low-abundance genera in vaginal and cervical microbiota of EMS patients, such as Fannyhessea, Prevotella, Streptococcus, Bifidobacterium, Veillonella, Megasphaera and Sneathia. Random forest analysis found that translocation of these genera had the significant importance in differentiating EMS patients from controls. In addition, cervix/vagina ratio of these genera also associated with EMS severity. And these genera had notable associations with ascending infection-related functional pathways, including flagellar assembly, bacterial motility proteins, bacterial toxins and epithelial cell signaling in Helicobacter pylori infection. These findings suggest that translocation of specific genera between vaginal and cervical sites play a role in EMS.

Microbiota in Irritable Bowel Syndrome and Endometriosis: Birds of a Feather Flock Together-A Review

Endometriosis and irritable bowel syndrome (IBS) are chronic conditions affecting up to 10% of the global population, imposing significant burdens on healthcare systems and patient quality of life. Interestingly, around 20% of endometriosis patients also present with symptoms indicative of IBS. The pathogenesis of both these multifactorial conditions remains to be fully elucidated, but connections to gut microbiota are becoming more apparent. Emerging research underscores significant differences in the gut microbiota composition between healthy individuals and those suffering from either endometriosis or IBS. Intestinal dysbiosis appears pivotal in both conditions, exerting an influence via similar mechanisms. It impacts intestinal permeability, triggers inflammatory reactions, and initiates immune responses. Furthermore, it is entwined in a bidirectional relationship with the brain, as part of the gut-brain axis, whereby dysbiosis influences and is influenced by mental health and pain perception. Recent years have witnessed the development of microbiota-focused therapies, such as low FODMAP diets, prebiotics, probiotics, antibiotics, and fecal microbiota transplantation, designed to tackle dysbiosis and relieve symptoms. While promising, these treatments present inconsistent data, highlighting the need for further research. This review explores the evidence of gut dysbiosis in IBS and endometriosis, underscoring the similar role of microbiota in both conditions. A deeper understanding of this common mechanism may enable enhanced diagnostics and therapeutic advancements.

The Impact of the Microbiological Vaginal Swab on the Reproductive Outcome in Infertile Women

BACKGROUND

The thesis on which this paper is based intended to investigate whether the result of the microbiological vaginal swab has an influence on the outcome of the fertility treatment.

METHODS

The microbiological vaginal swabs of patients who received fertility treatment at Saarland University Hospital were evaluated. Depending on the microorganisms detected, the swab result was classified as inconspicuous, intermediate, or conspicuous. The SPSS software was used to determine the correlation between the swab result and the outcome of the fertility treatment.

RESULTS

Dysbiosis was associated with a worse outcome of fertility treatment. The pregnancy rate with a conspicuous swab was 8.6%, whereas it was 13.4% with an inconspicuous swab. However, this association was not statistically significant. Furthermore, an association of endometriosis with dysbiosis was found. Endometriosis was more frequent with a conspicuous swab result than with an inconspicuous result (21.1% vs. 17.7%), yet the correlation was not statistically significant. However, the absence of lactobacilli was significantly associated with endometriosis (p = 0.021). The association between endometriosis and a lower pregnancy rate was also statistically significant (p = 0.006).

CONCLUSION

The microbiological vaginal and cervical swabs can be used as predictors for the success of fertility treatments. Further studies are needed to assess the impact of transforming a dysbiotic flora into a eubiotic environment on the success of fertility treatments.

Impact of Adenomyosis and Endometriosis on Chronic Pelvic Pain after Niche Repair

Chronic pelvic pain (CPP) is one of the main isthmocele symptoms, together with abnormal uterine bleeding and secondary infertility. When patients undergo a laparoscopic niche repair surgery, it is important to determine if they present associated pathologies, such as adenomyosis and/or endometriosis, which are also a cause of CPP. A retrospective study was performed on 31 patients with CPP undergoing a laparoscopic niche repair. The pre-operative ultrasound was analyzed to determine the presence of adenomyosis. Endometriosis was histologically diagnosed. CPP outcome was evaluated at early (3-6 months) and late (12 months) post-operative follow ups. In our population of 31 women presenting CPP, only six of them (19.4%) did not have any associated pathology. In the group of 25 patients with associated pathology, 10 (40%) had no benefit from the reconstructive surgery in terms of CPP at early follow-up (3-6 months) and 8 (32%) in the post-operative period at 12 months. Patients with CPP who undergo niche repair should be carefully selected as CPP does not seem to be a good indication for uterine scar repair in patients with concomitant adenomyosis and endometriosis.

Endometriosis and the Temporomandibular Joint-Preliminary Observations

(1) Background: The complete picture of the disease is not fully recognized and extends far beyond the pelvis. The disease's impacts lead to systemic inflammation, in turn resulting in sensitization to pain. The aim of this study was to check whether statistical correlations exist in women with endometriosis with regard to their experience of pain: headache, pelvic pain, temporomandibular joint pain, along with teeth clenching and the treatment of the disease. We constructed contingency tables, followed by Pearson's chi-square test and Cramer's V coefficient values. (2) Methods: A survey was conducted among 128 women aged 33.43 ± 5.79 with a diagnosis of endometriosis (disease duration 6.40 ± 5.88 years). (3) Results: There was a correlation between the occurrence of pain on the right and left sides of the pelvis and pain on the right and left sides of the temporomandibular joint, p-value = 0.0397, V = 0.2350, and between the presence of pelvic pain and the treatment of endometriosis, p-value = 0.0104, V = 0.3709, and between the presence of pain outside the pelvis and the treatment of endometriosis, p-value = 0.0311, V = 0.4549. There was a highly significant correlation between teeth clenching and temporomandibular joint pain, p-value = 0.0005, V = 0.3695. (4) Conclusions: The study revealed a correlation between pelvic endometriosis symptoms and symptoms in the temporomandibular joint.

Precision Medicine for Chronic Endometritis: Computer-Aided Diagnosis Using Deep Learning Model

Chronic endometritis (CE) is a localized mucosal infectious and inflammatory disorder marked by infiltration of CD138(+) endometrial stromal plasmacytes (ESPC). CE is drawing interest in the field of reproductive medicine because of its association with female infertility of unknown etiology, endometriosis, repeated implantation failure, recurrent pregnancy loss, and multiple maternal/newborn complications. The diagnosis of CE has long relied on somewhat painful endometrial biopsy and histopathologic examinations combined with immunohistochemistry for CD138 (IHC-CD138). With IHC-CD138 only, CE may be potentially over-diagnosed by misidentification of endometrial epithelial cells, which constitutively express CD138, as ESPCs. Fluid hysteroscopy is emerging as an alternative, less-invasive diagnostic tool that can visualize the whole uterine cavity in real-time and enables the detection of several unique mucosal findings associated with CE. The biases in the hysteroscopic diagnosis of CE; however, are the inter-observer and intra-observer disagreements on the interpretation of the endoscopic findings. Additionally, due to the variances in the study designs and adopted diagnostic criteria, there exists some dissociation in the histopathologic and hysteroscopic diagnosis of CE among researchers. To address these questions, novel dual immunohistochemistry for CD138 and another plasmacyte marker multiple myeloma oncogene 1 are currently being tested. Furthermore, computer-aided diagnosis using a deep learning model is being developed for more accurate detection of ESPCs. These approaches have the potential to contribute to the reduction in human errors and biases, the improvement of the diagnostic performance of CE, and the establishment of unified diagnostic criteria and standardized clinical guidelines for the disease.

Similarities in Pathogenetic Mechanisms Underlying the Bidirectional Relationship between Endometriosis and Pelvic Inflammatory Disease

BACKGROUND

Endometriosis is a common inflammatory disease characterized by the presence of endometrial cells outside of the uterine cavity. Endometriosis affects 10% of women of reproductive age and significantly reduces their quality of life as a result of chronic pelvic pain and infertility. Biologic mechanisms, including persistent inflammation, immune dysfunction, and epigenetic modifications, have been proposed as the pathogenesis of endometriosis. In addition, endometriosis can potentially be associated with an increased risk of pelvic inflammatory disease (PID). Changes in the vaginal microbiota associated with bacterial vaginosis (BV) result in PID or a severe form of abscess formation, tubo-ovarian abscess (TOA). This review aims to summarize the pathophysiology of endometriosis and PID and to discuss whether endometriosis may predispose to PID and vice versa.

METHODS

Papers published between 2000 and 2022 in the PubMed and Google Scholar databases were included.

RESULTS

Available evidence supports that women with endometriosis are at increased risk of comorbid PID and vice versa, supporting that endometriosis and PID are likely to coexist. There is a bidirectional relationship between endometriosis and PID that shares a similar pathophysiology, which includes the distorted anatomy favorable to bacteria proliferation, hemorrhage from endometriotic lesions, alterations to the reproductive tract microbiome, and impaired immune response modulated by aberrant epigenetic processes. However, whether endometriosis predisposes to PID or vice versa has not been identified.

CONCLUSIONS

This review summarizes our current understanding of the pathogenesis of endometriosis and PID and discusses the similarities between them.