The Role of Stem Cells in the Etiology and Pathophysiology of Endometriosis

Saliva, a molecular reflection of the human body? Implications for diagnosis and treatment

For many diseases, and cancer in particular, early diagnosis allows a wider range of therapies and a better disease management. This has led to improvements in diagnostic procedures, most often based on tissue biopsies or blood samples. Other biological fluids have been used to diagnose disease, and among them saliva offers a number of advantages because it can be collected non-invasively from large populations at relatively low cost. To what extent might saliva content reveal the presence of a tumour located at a distance from the oral cavity and the molecular information obtained from saliva be used to establish a diagnosis are current questions. This review focuses primarily on the content of saliva and shows how it potentially offers a source of diagnosis, possibly at an early stage, for pathologies such as cancers or endometriosis.

Intrauterine Infusion and Hysteroscopic Injection of Autologous Platelet-Rich Plasma for Patients with a Persistent Thin Endometrium: A Prospective Case-Control Study

Objectives: To evaluate the effect of intrauterine infusion and hysteroscopic injection of autologous platelet-rich plasma (PRP) in patients with a persistent thin endometrium (EM) undergoing euploid frozen embryo transfer (EFET) cycles. Methods: This prospective case-control study enrolled 116 infertile women with thin EM (<7 mm) who underwent hormone replacement therapy (HRT) for EFET. These women had experienced at least one previous unsuccessful EFET cycle, which either resulted in the cancellation of the cycle or failure of pregnancy. A total of 55 women received an intrauterine infusion of PRP before FET, 38 received a hysteroscopic injection of PRP, and 23 received standard HRT treatment without PRP (control group). Only euploid embryos were transferred in these cycles. The primary outcomes were the implantation rate (IR) and clinical pregnancy rate (CPR) after EFET. Results: After receiving intrauterine infusion and hysteroscopic injection of PRP, 78.2% and 55.3% of patients, respectively, showed an EM thickness exceeding 7 mm, followed by embryo transfer. The hysteroscopic injection group demonstrated significantly higher IR (52%), a higher trend of CPR (52%), and a higher live birth rate (38%) than the control group (18%, 22%, and 4%). Conclusions: Intrauterine infusion and hysteroscopic injection of autologous PRP may be effective methods to increase EM thickness in HRT cycles. According to our results, both methods could increase EM thickness, while hysteroscopic injection appeared to provide more significant assistance in increasing IR, CPR, and live birth rate after EFET in patients with persistent thin EM.

Disrupted Tuzzerella abundance and impaired L-glutamine levels induce Treg accumulation in ovarian endometriosis: a comprehensive multi-omics analysis

INTRODUCTION

The microbial community plays a crucial role in the pathological microenvironment. However, the structure of the microbial community within endometriotic lesions and its impact on the microenvironment is still limited.

METHODS

All 55 tissue samples, including ovarian ectopic (OEMs) and normal (NE) endometrium, were subjected to 16S rRNA sequencing, metabolomic and proteomic analysis.

RESULTS

We found the abundance of Tuzzerella is significantly lower in OEMs compared to NE tissue (p < 0.01). We selected samples from these two groups that exhibited the most pronounced difference in Tuzzerella abundance for further metabolomic and proteomic analysis. Our findings indicated that endometriotic lesions were associated with a decrease in L-Glutamine levels. However, proteomic analysis revealed a significant upregulation of proteins related to the complement pathway, including C3, C7, C1S, CLU, and A2M. Subsequent metabolic and protein correlation predictions demonstrated a negative regulation between L-Glutamine and C7. In vitro experiments further confirmed that high concentrations of Glutamine significantly inhibit C7 protein expression. Additionally, immune cell infiltration analysis, multiplex immunofluorescence, and multifactorial testing demonstrated a positive correlation between C7 expression and the infiltration of regulatory T cells (Tregs) in ectopic lesions, while L-Glutamine was found to negatively regulate the expression of chemotactic factors for Tregs.

CONCLUSION

In this study, we found a clear multi-omics pathway alteration, "Tuzzerella (microbe)-L-Glutamine (metabolite)-C7 (protein)," which affects the infiltration of Tregs in endometriotic lesions. Our findings provide insights into endometriosis classification and personalized treatment strategies based on microbial structures.

A protocol for creating endometriosis in rhesus macaques (Macaca mulatta)

BACKGROUND

Endometriosis is the presence of endometrium-like tissue outside the uterine cavity. An experimental model of endometriosis has been created in the baboon by the transcervical collection and laparoscopic inoculation of menstrual endometrium. Macaques are the preferred model for pharmaceutical development, but the complex anatomy of the macaque cervix makes the baboon method impractical. In this work, we sought to validate a surgical approach for creating endometriosis in macaques.

METHODS

Menstrual endometrium was collected via laparoscopic intrauterine puncture and transferred to the peritoneal cavity. We repeated this procedure during three menstruations. Endometriotic tissue was identified during laparoscopy, collected, and characterized by immunohistochemistry.

RESULTS

Sham surgery-treated animals (n = 3) failed to develop endometriosis. We identified red, powder burnt, and white lesions in 13/14 of the treated animals; the stroma of the red lesions stained positive for ovarian steroid receptors.

CONCLUSION

This surgical technique can reliably create hormone-responsive endometriosis in macaques for therapeutic studies.

Regeneration and anti-inflammatory effects of stem cells and their extracellular vesicles in gynecological diseases

There are many gynecological diseases, among which breast cancer (BC), cervical cancer (CC), endometriosis (EMs), and polycystic ovary syndrome (PCOS) are common and difficult to cure. Stem cells (SCs) are a focus of regenerative medicine. They are commonly used to treat organ damage and difficult diseases because of their potential for self-renewal and multidirectional differentiation. SCs are also commonly used for difficult-to-treat gynecological diseases because of their strong directional differentiation ability with unlimited possibilities, their tendency to adhere to the diseased tissue site, and their use as carriers for drug delivery. SCs can produce exosomes in a paracrine manner. Exosomes can be produced in large quantities and have the advantage of easy storage. Their safety and efficacy are superior to those of SCs, which have considerable potential in gynecological treatment, such as inhibiting endometrial senescence, promoting vascular reconstruction, and improving anti-inflammatory and immune functions. In this paper, we review the mechanisms of the regenerative and anti-inflammatory capacity of SCs and exosomes in incurable gynecological diseases and the current progress in their application in genetic engineering to provide a foundation for further research.

Unraveling immunotherapeutic targets for endometriosis: a transcriptomic and single-cell analysis

Background

Endometriosis (EMs), a common gynecological disorder, adversely affects the quality of life of females. The pathogenesis of EMs has not been elucidated and the diagnostic methods for EMs have limitations. This study aimed to identify potential molecular biomarkers for the diagnosis and treatment of EMs.

Methods

Differential gene expression (DEG) and functional enrichment analyses were performed using the R language. WGCNA, Random Forest, SVM-REF and LASSO methods were used to identify core immune genes. The CIBERSORT algorithm was then used to analyse the differences in immune cell infiltration and to explore the correlation between immune cells and core genes. In addition, the extent of immune cell infiltration and the expression of immune core genes were investigated using single-cell RNA (scRNA) sequencing data. Finally, we performed molecular docking of three core genes with dienogest and goserelin to screen for potential drug targets.

Results

DEGs enriched in immune response, angiogenesis and estrogen processes. CXCL12, ROBO3 and SCG2 were identified as core immune genes. RT-PCR confirmed that the expression of CXCL12 and SCG2 was significantly upregulated in 12Z cells compared to hESCs cells. ROC curves showed high diagnostic value for these genes. Abnormal immune cell distribution, particularly increased macrophages, was observed in endometriosis. CXCL12, ROBO3 and SCG2 correlated with immune cell levels. Molecular docking suggested their potential as drug targets.

Conclusion

This study investigated the correlation between EMs and the immune system and identified potential immune-related biomarkers. These findings provided valuable insights for developing clinically relevant diagnostic and therapeutic strategies for EMs.

Endometrial and placental stem cells in successful and pathological pregnancies

The endometrium is a dynamic tissue that undergoes extensive remodeling during the menstrual cycle and further gets modified during pregnancy. Different kinds of stem cells are reported in the endometrium. These include epithelial stem cells, endometrial mesenchymal stem cells, side population stem cells, and very small embryonic-like stem cells. Stem cells are also reported in the placenta which includes trophoblast stem cells, side population trophoblast stem cells, and placental mesenchymal stem cells. The endometrial and placental stem cells play a pivotal role in endometrial remodeling and placental vasculogenesis during pregnancy. The dysregulation of stem cell function is reported in various pregnancy complications like preeclampsia, fetal growth restriction, and preterm birth. However, the mechanisms by which it does so are yet elusive. Herein, we review the current knowledge of the different type of stem cells involved in pregnancy initiation and also highlight how their improper functionality leads to pathological pregnancy.

Endometriosis in an ectopic kidney: a rare case report and literature review

BACKGROUND

Endometriosis mainly occurs in female pelvic organs. Endometriosis in the kidney is extremely rare.

CASE PRESENTATION

We herein describe a case of a 19-year-old girl with occasional mild abdominal pain associated with an ectopic left kidney. SPECT-CT showed no abnormal radioactive distribution in the left pelvis, suggesting loss of function of the ectopic kidney. Laparoscopic left ectopic kidney resection was subsequently performed. Histopathology revealed endometriosis of the ectopic left kidney.

CONCLUSIONS

In female patients with clinical manifestations of abdominal pain and gross hematuria, the possibility of renal endometriosis should be considered.

Total Flavonoids of Polygala fallax Hemsl Induce Apoptosis of Human Ectopic Endometrial Stromal Cells through PI3K/AKT/Bcl-2 Signaling Pathway

OBJECTIVE

The objective of this study was to explore the inhibitory effect of total flavonoids of Polygala fallax Hemsl (PFHF) on human ectopic endometrial stromal cells (HEcESCs) and its mechanism.

DESIGN

The apoptosis, cell cycle, migration, and invasion ability of HEcESCs (Fresh human ovarian endometriosis tissue was used for primary culture) after PFHF treatment were detected, and the mechanism of action was explored.

MATERIALS

The Polygala fallax Hemsl (PFH), RPMI 1640 culture medium, Dulbecco's modified Eagle's medium (DMEM)/F-12, fetal bovine serum, penicillin/streptomycin, cell counting kit-8 (CCK-8) kit, trypsin, phenylmethylsulfonyl fluoride, radioimmunoprecipitation assay tissue/cell lysate, bicinchoninic acid protein concentration detection kits, protein loading buffer, the apoptosis and cell cycle extraction kits, the matrix glue, TRIzol Universal Reagent, the reverse transcription kit, AB HS Green qPCR Mix, the ECL chromogenic solution, enzyme labeling instrument, flow cytometry, automatic real-time fluorescence quantitative PCR instrument, Goat anti-rabbit, rabbit anti-β-actin, vimentin, phosphatidylinositol 3 kinase (PI3K), protein kinase B (AKT), B-cell lymphoma-2 (Bcl-2), Bcl-extra long (Bcl-xl), Bcl-2 associated death promoter (Bad) antibody, Alexa Fluor 594-labeled secondary antibody, the inverted microscope, the constant temperature carbon dioxide cell incubator.

SETTING

Five parts included introduction, materials and methods, results, discussion, and conclusion.

METHODS

The potential targets and pathways of PFHF in the treatment of endometriosis were predicted by network pharmacology. The effect of PFHF on the proliferation, apoptosis and cell cycle, migration, and invasion of HEcESCs was detected by CCK-8 method, flow cytometry, and Transwell chamber experiment. Label-free quantitative proteomics based on mass spectrometry was used to analyze the protein mass spectrum of differential expression of HEcESCs before and after PFHF, and the biological information was analyzed. The effects of PFHF on the mRNA and protein expression of pathway-related genes predicted in HEcESCs were detected by reverse transcription-quantitative polymerase chain reaction and Western blotting.

RESULTS

The network pharmacology predicts that PFHF treats endometriosis through PI3K/AKT signaling pathway. Compared with control group (DMEM/F-12 medium alone), the high dose PFHF can significantly reduce the viability, migration, and invasion of HEcESCs, increase the apoptosis rate of HEcESCs, and make the HEcESCs accumulated in G0/G1 phase in a time- and dose-dependent manner (p < 0.05). The analysis of label-free quantitative proteomics indicated that PFHF flavonoids may induce apoptosis of EESCs through PI3K/AKT signaling pathway. The results of RT-qPCR and Western blotting showed that the expressions of PI3K, AKT, Bcl-2, and Bcl-xl were significantly downregulated, while the bad expression was upregulated in HEcESCs treated with PFHF (p < 0.05).

LIMITATIONS

This research investigated the effects of PFHF on the stromal endometriotic cells only. So it is unknown how PFHF can affect the entire endometriotic lesion. And the research is carried out in vitro, which gives no impression about the bioavailability of the flavonoids.

CONCLUSION

PFHF reduces the expression of PI3K, AKT, Bcl-2, and Bcl-xl through the PI3K/AKT/Bcl-2 signaling pathway to inhibit HEcESCs proliferation, migration, and invasion and promote their apoptosis.

Endometriosis Stem Cells as a Possible Main Target for Carcinogenesis of Endometriosis-Associated Ovarian Cancer (EAOC)

Endometriosis is a serious recurrent disease impairing the quality of life and fertility, and being a risk for some histologic types of ovarian cancer defined as endometriosis-associated ovarian cancers (EAOC). The presence of stem cells in the endometriotic foci could account for the proliferative, migrative and angiogenic activity of the lesions. Their phenotype and sources have been described. The similarly disturbed expression of several genes, miRNAs, galectins and chaperones has been observed both in endometriotic lesions and in ovarian or endometrial cancer. The importance of stem cells for nascence and sustain of malignant tumors is commonly appreciated. Although the proposed mechanisms promoting carcinogenesis leading from endometriosis into the EAOC are not completely known, they have been discussed in several articles. However, the role of endometriosis stem cells (ESCs) has not been discussed in this context. Here, we postulate that ESCs may be a main target for the carcinogenesis of EAOC and present the possible sequence of events resulting finally in the development of EAOC.

Roles of microRNAs in Regulating Apoptosis in the Pathogenesis of Endometriosis

Endometriosis is a gynecologic disorder characterized by the presence of endometrial tissues outside the uterine cavity affecting reproductive-aged women. Previous studies have shown that microRNAs and their target mRNAs are expressed differently in endometriosis, suggesting that this molecule may play a role in the development and persistence of endometriotic lesions. microRNA (miRNA), a small non-coding RNA fragment, regulates cellular functions such as cell proliferation, differentiation, and apoptosis by the post-transcriptional modulation of gene expression. In this review, we focused on the dysregulated miRNAs in women with endometriosis and their roles in the regulation of apoptosis. The dysregulated miRNAs and their target genes in this pathophysiology were highlighted. Circulating miRNAs as potential biomarkers for the diagnosis of endometriosis have also been identified. As shown by various studies, miRNAs were reported to be a potent regulator of gene expression in endometriosis; thus, identifying the dysregulated miRNAs and their target genes could help discover new therapeutic targets for treating this disease. The goal of this review is to draw attention to the functions that miRNAs play in the pathophysiology of endometriosis, particularly those that govern cell death.

Pathogenesis of Human Adenomyosis: Current Understanding and Its Association with Infertility

The aim of this review article was to summarize our current understanding on the etiologies and pathogenesis of human adenomyosis and to clarify the relative association between adenomyosis and infertility. The exact pathogenesis of adenomyosis is still elusive. Among different reported concepts, direction invagination of gland cells from the basalis endometrium deep into myometrium is the most widely accepted opinion on the development of adenomyosis. According to this concept, endometrial epithelial cells and changed fibroblasts, abnormally found in the myometrium in response to repeated tissue injury and/or disruption at the endometrium-myometrium interface (EMI), elicit hyperplasia and hypertrophy of the surrounding smooth muscle cells. In this review, a comprehensive review was performed with a literature search using PubMed for all publications in English and Japanese (abstract in English), related to adenomyosis and infertility, from inception to April 2021. As an estrogen-regulated factor, hepatocyte growth factor (HGF) exhibits multiple functions in endometriosis, a disease commonly believed to arise from the functionalis endometrium. As a mechanistic basis of gland invagination, we investigated the role of HGF, either alone or in combination with estrogen, in the occurrence of epithelial-mesenchymal transition (EMT) in adenomyosis. Aside from microtrauma at the EMI, metaplasia of displaced Müllerian remnants, differentiation of endometrial stem/progenitor cells within the myometrium and somatic mutation of some target genes have been put forward to explain how adenomyosis develops. In addition, the possible role of microRNAs in adenomyosis is also discussed. Besides our knowledge on the conventional classification (focal and diffuse), two recently proposed classifications (intrinsic and extrinsic) of adenomyosis and the biological differences between them have been described. Although the mechanistic basis is unclear, the influence of adenomyosis on fertility outcome is important, especially considering the recent tendency to delay pregnancy among women. Besides other proposed mechanisms, a recent transmission election microscopic (TEM) study indicated that microvilli damage and an axonemal alteration in the apical endometria of human adenomyosis, in response to endometrial inflammation, may be involved in negative fertility outcomes. We present a critical analysis of the literature data concerning the mechanistic basis of infertility in women with adenomyosis and its impact on fertility outcome.

Peritoneal Pathology Review: Mullerian, Mucinous and Mesothelial Lesions

This review provides an overview of the pathology of selected benign and malignant lesions of the female peritoneum and their often-encountered differential diagnoses. It includes endometriosis and its related lesions, endosalpingiosis, pseudomyxoma peritonei (PMP) and related ovarian/appendiceal pathology, and malignant and benign mesothelial tumors. The current terminology associated with PMP is also discussed.

The colonized microbiota composition in the peritoneal fluid in women with endometriosis

PURPOSE

The imbalance of microbiome in vivo is believed to be involved in the pathogenicity of endometriosis. This study aimed to investigate and analyze the composition of bacterial communities in the peritoneal fluid of women with endometriosis.

METHODS

To collect peritoneal fluid samples from women with (N = 36) and without (N = 25) endometriosis in a generalized hospital in Hunan, China during January to December of 2019. Genomic DNA was extracted from peritoneal fluid samples, and targeted amplified for the V4 region of 16S ribosomal RNA gene followed by amplicon sequencing. Non-parametric Wilcoxon rank-sum test and chi-squared test were used to compare and analysis the difference between groups.

RESULTS

Analysis showed that microbiota diversity was similar in the peritoneal fluid of women with or without endometriosis. Ralstonia mainly dominated in the peritoneal fluid of patients in both groups, with an overall relative abundance of 11.15% (95% CI: 10.51-11.80%) in endometriosis patients, followed by Acinetobacter, Pseudomonas, Asticcacaulis, and Methyloversatilis, with no significant difference between endometriosis patients and the control group. Nevertheless, there were microbes with different abundance in peritoneal fluid of the two groups, and the relative abundance was less than 0.5%. Acidovorax (P = 0.01), Devosia (P = 0.03), Methylobacterium (P = 0.03), Phascolarctobacterium (P = 0.03), and Streptococcus (P = 0.04) were more abundant in the peritoneal fluid of endometriosis patients than the controls, while Brevundimonas (P = 0.01) and Stenotrophomonas (P = 0.04) were less abundant.

CONCLUSION

The composition of minority microbiota including Acidovorax, Devosia, Methylobacterium, Phascolarctobacterium, and Streptococcus in peritoneal fluid were found to change among women with endometriosis. Further research is needed to explore the mechanisms of these microorganisms in the pathophysiology of endometriosis.

[Mystery of endometriosis - catamenial pneumothorax]

The review is devoted to clinical picture, main theories of pathogenesis, traditional and innovative methods of diagnosis and surgical treatment of catamenial pneumothorax. Currently, clinicians prefer magnetic resonance imaging and thoracoscopy for diagnosis of this disease. Various researchers are actively searching for laboratory diagnostic methods that can confirm endometrioid nature of pneumothorax. Treatment and prevention of catamenial pneumothorax are a controversial issue depending both clinical picture and preferences of the attending physician. Currently, the majority of authors believe that hormonal therapy combined with diaphragm resection ensures optimal anti-relapse effect in patients with thoracic endometriosis.

Bioinformatical analysis of the key differentially expressed genes and associations with immune cell infiltration in development of endometriosis

Background

This study explored the key genes related to immune cell infiltration in endometriosis.

Results

The Gene Expression Omnibus (GEO) datasets (GSE7305, GSE7307, and GSE11691), containing a total of 37 endometriosis and 42 normal tissues, were retrieved and analyzed to determine the differentially expressed genes (DEGs). Gene ontology (GO) annotations and Kyoto Encyclopedia of Genes (KEGG) analysis were performed to identify the pathways that were significantly enriched. The xCell software was used to analyze immune cell infiltration and correlation analyses were performed to uncover the relationship between key genes and immune cells. The analysis identified 1031 DEGs (581 upregulated and 450 downregulated DEGs), while GO analysis revealed altered extracellular matrix organization, collagen-containing extracellular matrix, and glycosaminoglycan binding and KEGG enrichment showed genes related to metabolic pathways, pathways in cancer, phosphatidylinositol 3-kinase-protein kinase B (PI3K-Akt) signaling, proteoglycans in cancer, and the mitogen-activated protein kinase (MAPK) signaling pathway. Furthermore, the protein–protein interaction network revealed 10 hub genes, i.e., IL6, FN1, CDH1, CXCL8, IGF1, CDK1, PTPRC, CCNB1, MKI67, and ESR1. The xCell analysis identified immune cells with significant changes in all three datasets, including CD4⁺ and CD8⁺ T cells, CD8⁺ Tem, eosinophils, monocytes, Th1 cells, memory B-cells, activated dendritic cells (aDCs), and plasmacytoid dendritic cells (pDCs). These 10 hub genes were significantly associated with at least three types of immune cells.

Conclusions

Aberrant gene expression was related to abnormal infiltration of different immune cells in endometriosis and was associated with endometriosis development by affecting the tissue microenvironment and growth of ectopic endometrial cells.

A Revised Stem Cell Theory for the Pathogenesis of Endometriosis

During the past decade, a stem cell-based hypothesis has emerged (among many others) to explain the pathogenesis of endometriosis. The initial hypothesis proposed that endometriosis arose from a single or a few specific cells with stem cell properties, including self-renewal and multi-lineage cell differentiation. The origins of the endometriosis-initiating stem cells were thought to be the bone marrow, uterine endometrium, and other tissues. Based on the implantation or metastatic theory in combination with the initial stem cell theory, one or a few multipotent stem/progenitor cells present in the eutopic endometrium or bone marrow translocate to ectopic sites via fallopian tubes during menstruation, vasculolymphatic routes, or through direct migration and invasion. Subsequently, they give rise to endometriotic lesions followed by differentiation into various cell components of endometriosis, including glandular and stromal cells. Recent somatic mutation analyses of deep infiltrating endometriosis, endometrioma, and eutopic normal endometrium using next-generation sequencing techniques have redefined the stem cell theory. It is now proposed that stem/progenitor cells of at least two different origins—epithelium and stroma—sequentially, differentially, but coordinately contribute to the genesis of endometriosis. The dual stem cell theory on how two (or more) stem/progenitor cells differentially and coordinately participate in the establishment of endometriotic lesions remains to be elucidated. Furthermore, the stem/progenitor cells involved in this theory also remain to be identified. Given that the origin of endometriosis is eutopic endometrium, the candidate cells for endometriotic epithelium-initiating cells are likely to be endometrial epithelial cells positive for either N-cadherin or SSEA-1 or both. The candidate cells for endometriotic stroma-initiating cells may be endometrial mesenchymal stem cells positive for SUSD2. Endometrial side population cells are also a possible candidate because they contain unipotent or multipotent cells capable of behaving as endometrial epithelial and stromal stem/progenitor cells.

Mode Switch of Ca2 + Oscillation-Mediated Uterine Peristalsis and Associated Embryo Implantation Impairments in Mouse Adenomyosis

Adenomyosis is a debilitating gynecological disease of the uterus with no medicinal cure. The tissue injury and repair hypothesis for adenomyosis suggests that uterine hyperperistalsis or dysperistalsis plays a pivotal role in establishing adenomyotic lesions. However, specific impairments in uterine peristalsis and the underlying cellular signals for these changes in adenomyosis remain elusive. Here, we report a precision-cut uterine slice preparation that preserves in vivo uterine architecture and generates peristalsis similar to that seen in the whole uterus. We found that uterine peristalsis in neonatal mice at day 14 and adult mice at day 55 presents as bursts with multiple peaks induced by intracellular Ca²⁺ oscillations. Using a mouse model of adenomyosis induced by tamoxifen, a selective estrogen receptor modulator, we discovered that uterine peristalsis and Ca²⁺ oscillations from adenomyotic uteri on days 14 and 55 become spikes (single peaks) with smaller amplitudes. The peak frequency of Ca²⁺ oscillations or peristalsis does not show a difference between control and adenomyotic mice. However, both the estimated force generated by uterine peristalsis and the total Ca²⁺ raised by Ca²⁺ oscillations are smaller in uteri from adenomyotic mice. Uteri from adenomyotic mice on day 14, but not on day 55, exhibit hyperresponsiveness to oxytocin. Embryo implantations are decreased in adenomyotic adult mice. Our results reveal a mode switch from bursts to spikes (rather than an increased peak frequency) of uterine Ca²⁺ oscillations and peristalsis and concurrent hyperresponsiveness to oxytocin in the neonatal stage are two characteristics of adenomyosis. These characteristics may contribute to embryo implantation impairments and decreased fertility in adenomyosis.

Brief Review of Endometriosis and the Role of Trace Elements

Endometriosis is a chronic, estrogen-dependent, inflammatory condition that is defined as the presence of endometrial glands and stroma outside the uterine cavity. Despite the progress in research into the mechanisms leading to the development of endometriosis, its cause has not yet been established. It seems to be possible that the formation of oxidative stress may be one of the main causes of the development of endometriosis. There is much research that studies the potential role of trace elements in the appearance of endometrial-like lesions. Most studies focus on assessing the content of selected trace elements in the blood, urine, or peritoneal fluid in women with endometriosis. Meanwhile, little is known about the content of these elements in endometrial-like implants, which may be helpful in developing the theory of endometriosis. Investigations that are more comprehensive are needed to confirm a hypothesis that some trace elements play a role in the pathomechanism of endometriosis.

Iron overload compromises preimplantation mouse embryo development

We and others have previously shown that abnormal pelvic environment plays an important role in the unexplained infertility of endometriosis. However, whether iron overload caused by ectopic periodic bleeding found in patients with endometriosis participates in endometriosis-associated reproductive failure is unknown. This study aimed to investigate effects of iron at level relevant to pelvic iron overload on the development of preimplantation mouse embryo. Two-cell embryos were collected, and cultured to blastocysts in G1/G2 medium supplemented with iron alone or in combination with iron chelator. The development rates, ATP level, mitochondrial membrane potential (MMP), reactive oxygen species level (ROS), and apoptotic and ferroptotic indices were compared between control and iron treatments across each specific developmental stage. Prolonged exposure to iron remarkably impaired early embryo development in vitro by hampering blastocyst formation (P < 0.001), which could be partly restored by iron chelator (P < 0.001). The arrest of embryo development was linked with iron-initiated mitochondrial dysfunction with reduction of ATP generation and MMP (P < 0.05 and P < 0.001, respectively). Impaired mitochondria altered ROS accumulation post-iron exposure at morula stage and blastocyst stage (P < 0.05). Moreover, Iron-exposed blastocyst stage embryos showed higher apoptotic and ferroptotic rates (P < 0.001 and P < 0.05, respectively). Our results highlight that pathologically relevant level of iron compromises preimplantation mouse embryo development by disrupting mitochondrial function and triggering both apoptosis and ferroptosis, which implicates that excess iron found in peritoneal fluid of women with endometriosis likely participates in endometriosis-associated reproductive failure.

Endometrial stem/progenitor cells and their roles in immunity, clinical application, and endometriosis

Endometrial stem/progenitor cells have been proved to exist in periodically regenerated female endometrium and can be divided into three categories: endometrial epithelial stem/progenitor cells, CD140b+CD146+ or SUSD2+ endometrial mesenchymal stem cells (eMSCs), and side population cells (SPs). Endometrial stem/progenitor cells in the menstruation blood are defined as menstrual stem cells (MenSCs). Due to their abundant sources, excellent proliferation, and autotransplantation capabilities, MenSCs are ideal candidates for cell-based therapy in regenerative medicine, inflammation, and immune-related diseases. Endometrial stem/progenitor cells also participate in the occurrence and development of endometriosis by entering the pelvic cavity from retrograde menstruation and becoming overreactive under certain conditions to form new glands and stroma through clonal expansion. Additionally, the limited bone marrow mesenchymal stem cells (BMDSCs) in blood circulation can be recruited and infiltrated into the lesion sites, leading to the establishment of deep invasive endometriosis. On the other hand, cell derived from endometriosis may also enter the blood circulation to form circulating endometrial cells (CECs) with stem cell-like properties, and to migrate and implant into distant tissues. In this manuscript, by reviewing the available literature, we outlined the characteristics of endometrial stem/progenitor cells and summarized their roles in immunoregulation, regenerative medicine, and endometriosis, through which to provide some novel therapeutic strategies for reproductive and cancerous diseases.

Inhibition of METTL3/m6A/miR126 promotes the migration and invasion of endometrial stromal cells in endometriosis

N6-methyladenosine (m6A), one of the most abundant RNA modifications, is involved in the progression of many diseases, but its role and related molecular mechanisms in endometriosis remain unknown. To address these issues, we detected m6A levels in normal, eutopic and ectopic endometrium and found the m6A levels decreased in eutopic and ectopic endometrium compared with normal endometrium. In addition, we proved that methyltransferase-like 3 (METTL3) downregulation accounted for m6A reduction in endometriosis. Furthermore, we observed that METTL3 knockdown facilitated the migration and invasion of human endometrial stromal cells (HESCs), while METTL3 overexpression exerted opposite effects, suggesting that METTL3 downregulation might contribute to endometriosis development by enhancing cellular migration and invasion. Mechanistically, METTL3-dependent m6A was involved in the DGCR8-mediated maturation of primary microRNA126 (miR126, pri-miR126). Moreover, miR126 inhibitor significantly enhanced the migration and invasion of METTL3-overexpressing HESCs, whereas miR126 mimics attenuated the migration and invasion of METTL3-silenced HESCs. Our study revealed the METTL3/m6A/miR126 pathway, whose inhibition might contribute to endometriosis development by enhancing cellular migration and invasion. It also showed that METTL3 might be a novel diagnostic biomarker and therapeutic target for endometriosis.

Identification of endometriosis-associated genes and pathways based on bioinformatic analysis

Endometriosis is associated with dysmenorrhea, chronic pelvic pain, and infertility. The specific mechanism of endometriosis remains unclear. The aim of this study was to apply a bioinformatics approach to reveal related pathways or genes involved in the development of endometriosis.The gene expression profiles of GSE25628, GSE5108, and GSE7305 were downloaded from the gene expression omnibus (GEO) database. Differentially expressed gene (DEG) analysis was performed using GEO2R. The database for annotation, visualization, and integrated discovery (DAVID) was utilized to analyze the functional enrichment, gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) pathway of the differentially expressed genes. A protein-protein interaction (PPI) network was constructed and module analysis was performed using search tool for the retrieval of interacting genes and cytoscape.A total of 119 common differentially expressed genes were extracted, consisting of 51 downregulated genes and 68 upregulated genes. The enriched functions and pathways of the DEGs and hub genes include DNA strand separation, cellular proliferation, degradation of the extracellular matrix, encoding of smooth muscle myosin as a major contractile protein, exiting the proliferative cycle and entering quiescence, growth regulation, and implication in a wide variety of biological processes.A bioinformatics approach combined with cell experiments in this study revealed that identifying DEGs and hub genes leads to better understanding of the molecular mechanisms underlying the progression of endometriosis, and efficient biomarkers underlying this pathway need to be further investigated.

Intricate Connections between the Microbiota and Endometriosis

Imbalances in gut and reproductive tract microbiota composition, known as dysbiosis, disrupt normal immune function, leading to the elevation of proinflammatory cytokines, compromised immunosurveillance and altered immune cell profiles, all of which may contribute to the pathogenesis of endometriosis. Over time, this immune dysregulation can progress into a chronic state of inflammation, creating an environment conducive to increased adhesion and angiogenesis, which may drive the vicious cycle of endometriosis onset and progression. Recent studies have demonstrated both the ability of endometriosis to induce microbiota changes, and the ability of antibiotics to treat endometriosis. Endometriotic microbiotas have been consistently associated with diminished Lactobacillus dominance, as well as the elevated abundance of bacterial vaginosis-related bacteria and other opportunistic pathogens. Possible explanations for the implications of dysbiosis in endometriosis include the Bacterial Contamination Theory and immune activation, cytokine-impaired gut function, altered estrogen metabolism and signaling, and aberrant progenitor and stem-cell homeostasis. Although preliminary, antibiotic and probiotic treatments have demonstrated efficacy in treating endometriosis, and female reproductive tract (FRT) microbiota sampling has successfully predicted disease risk and stage. Future research should aim to characterize the "core" upper FRT microbiota and elucidate mechanisms behind the relationship between the microbiota and endometriosis.

Ultrasound Imaging of Abdominal Wall Endometriosis: A Pictorial Review

Endometriosis is a debilitating disease characterized by endometrial glands and stroma outside the endometrial cavity. Abdominal wall endometriosis (AWE) indicates the presence of ectopic endometrium between the peritoneum and the skin, including subcutaneous adipose tissue and muscle layers, often following obstetric and gynecological surgical procedures. AWE is a not infrequent gynecological surgical complication, due to the increasing number of cesarean sections worldwide. In this pictorial review, we discuss the importance of medical history and physical examination, including the main ultrasound features in the diagnosis of AWE.

Endometriosis is a chronic systemic disease: clinical challenges and novel innovations

Endometriosis is a common disease affecting 5-10% of women of reproductive age globally. However, despite its prevalence, diagnosis is typically delayed by years, misdiagnosis is common, and delivery of effective therapy is prolonged. Identification and prompt treatment of endometriosis are essential and facilitated by accurate clinical diagnosis. Endometriosis is classically defined as a chronic, gynaecological disease characterised by endometrial-like tissue present outside of the uterus and is thought to arise by retrograde menstruation. However, this description is outdated and no longer reflects the true scope and manifestations of the disease. The clinical presentation is varied, the presence of pelvic lesions is heterogeneous, and the manifestations of the disease outside of the female reproductive tract remain poorly understood. Endometriosis is now considered a systemic disease rather than a disease predominantly affecting the pelvis. Endometriosis affects metabolism in liver and adipose tissue, leads to systemic inflammation, and alters gene expression in the brain that causes pain sensitisation and mood disorders. The full effect of the disease is not fully recognised and goes far beyond the pelvis. Recognition of the full scope of the disease will facilitate clinical diagnosis and allow for more comprehensive treatment than currently available. Progestins and low-dose oral contraceptives are unsuccessful in a third of symptomatic women globally, probably as a result of progesterone resistance. Oral gonadotropin-releasing hormone (GnRH) antagonists constitute an effective and tolerable therapeutic alternative when first-line medications do not work. The development of GnRH antagonists has resulted in oral drugs that have fewer side-effects than other therapies and has allowed for rapid movement between treatments to optimise and personalise endometriosis care. In this Review, we discuss the latest understanding of endometriosis as a systemic disease with multiple manifestations outside the parameters of classic gynaecological disease.

Protective effects of mesenchymal stem cells on ischemic brain injury: therapeutic perspectives of regenerative medicine

Cerebral ischemic injury as the main manifestation of stroke can occur in stroke patients (70-80%). Nowadays, the main therapeutic strategy used for ischemic brain injury treatment aims to achieve reperfusion, neuroprotection, and neurorecovery. Also, angiogenesis as a therapeutic approach maybe represents a promising tool to enhance the prognosis of cerebral ischemic stroke. Unfortunately, although many therapeutic approaches as a life-saving gateway for cerebral ischemic injuries like pharmacotherapy and surgical treatments are widely used, they all fail to restore or regenerate damaged neurons in the brain. So, the suitable therapeutic approach would focus on regenerating the lost cells and restore the normal function of the brain. Currently, stem cell-based regenerative medicine introduced a new paradigm approach in cerebral ischemic injuries treatment. Today, in experimental researches, different types of stem cells such as mesenchymal stem cells have been applied. Therefore, stem cell-based regenerative medicine provides the opportunity to inquire and develop a more effective and safer therapeutic approach with the capability to produce and regenerate new neurons in damaged tissues.

Pathology and Pathogenesis of Adenomyosis

Adenomyosis represents a unique pathophysiological condition in which normal-appearing endometrial mucosa resides within myometrium and is thus protected from menstrual shedding. The resulting ectopic presence of endometrial tissue composed of glands and stroma is thought to affect normal contractile function and peristalsis of uterine smooth muscle, causing menometrorrhagia, infertility, and adverse obstetric outcomes. Since the first description of adenomyosis more than 150 years ago, pathologists have studied this lesion by examining tissue specimens, and have proposed multiple explanations to account for its pathogenesis. However, as compared with endometriosis, progress of adenomyosis research has been, at best, incremental mainly due to the lack of standardized protocols in sampling tissue and a lack of consensus diagnostic criteria in pathology practice. Despite these limitations, recent advances in revealing the detailed anatomy and biology of eutopic endometrium offer an unprecedented opportunity to study this common but relatively understudied disorder. Here, we briefly summarize the pathological aspects of adenomyosis from an historical background, and discuss conventional morphology and recent tissue-based molecular studies with a special emphasis on elucidating its tissue of origin from a pathologist's perspective. We also discuss unmet needs in pathology studies that would be important for advancing adenomyosis research.

Splenic lesion mimicking breast metastasis: The first description of splenic parenchymal endometriosis

Introduction:

Splenic parenchymal endometriosis has never been described to date. We report here the case of real parenchymal endometriosis of the spleen.

Case description:

In this case, a 54-year-old female patient presented a histologically proven metastatic recurrence of breast cancer in the internal breast chain. The CT-scan also detected a large cystic structure developed from the spleen, but non-suspected to be metastasis. The patient was treated with chemotherapy (paclitaxel) and a combination of targeted therapies (everolimus and trastuzumab). While a complete radiological and biological response was noted at 2 months, the splenic cyst gradually decreased over the years. When targeted therapies were stopped, a reincrease of the splenic lesion and de novo significant hypermetabolism of the splenic parenchyma on 18F-FDG PET scan were observed. A splenectomy was finally performed and revealed splenic parenchymal endometriosis.

Conclusion:

This case once again highlights the complexity of endometriosis disease, from a pathophysiological point of view, but also the difficulties of radiological characterisation, and diagnostic management.

Management of a Thin Endometrium by Hysteroscopic Instillation of Platelet-Rich Plasma Into The Endomyometrial Junction: A Pilot Study

In patients whose embryo transfer has been previously canceled due to a thin endometrium, the injection of platelet-rich plasma (PRP) guided by hysteroscopy into the endomyometrial junction improves endometrial thickness and vascularity. This may well serve as a novel approach for the management of these patients. In this study, 32 patients aged between 27 and 39 years, suffering from primary or secondary infertility, were selected for hysteroscopic instillation of PRP. This cross-sectional study included a retrospective assessment of the improvement of endometrial thickness (>7 mm) on the commencement of progesterone treatment in 24 of 32 patients (75%) after hysteroscopy-guided injections of PRP into the subendometrial zone. After PRP instillation, the endometrium was 7 mm or thicker in 24 of 32 patients, and all 24 patients underwent frozen embryo transfer. Moreover, 12 of 24 patients who underwent embryo transfer conceived, whereas 10 had a clinical pregnancy with visualization of cardiac activity at 6 weeks and two had a biochemical pregnancy. Our approach of PRP injection into the subendometrial region is consistent with the histologically proven regeneration of the endometrium from the endomyometrial junction. We observed an improvement of endometrial thickness and higher pregnancy rates in cases of previously canceled embryo transfer due to a thin endometrium.

17β-estradiol promotes bone marrow mesenchymal stem cell migration mediated by chemokine upregulation

Bone marrow-derived cells engraft to the uterine endometrium and contribute to endometriosis. This study sought to further confirm that estrogen can promote the migration of bone marrow mesenchymal stem cells (BMSCs) and to investigate the function of estrogen on the secretion of chemokines during BMSC migration. BMSCs were treated with or without 17β-estradiol, cultured with or without endometrial stromal cells (ESCs), or pretreated with or without AMD 3100 (an antagonist of the SDF-1α receptor) before co-culture. A migration assay was used to investigate the changes in the migration of BMSCs. The secretion of chemokines in the co-culture medium was detected by chemokine analysis, and the mRNA expression of SDF-1α in cells was tested using quantitative real-time PCR. The results revealed that the migration of BMSCs was promoted by ESC, and the migration ability of BMSCs was enhanced after treatment with 17β-estradiol (p < 0.05). Through chemokine analysis, we further showed that 17β-estradiol promoted the secretion of chemokines especially for SDF-1α (p < 0.05). Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that these chemokines were mainly linked to the cytokine signaling pathway and interaction with cytokines receptors. Furthermore, the expression of SDF-1α mRNA was significantly increased in the 17β-estradiol treatment group (p < 0.001), and the migration of BMSCs was blocked by the use of our SDF-1α antagonist (p < 0.01). Our results indicate that 17β-estradiol could promote the chemotaxis and migration of BMSCs by up-regulating the secretion of chemokines, especially SDF-1α. Our study provides additional evidence to support and supplement the stem cell theory of endometriosis.

Biological characteristics of endometriotic mesenchymal stem cells isolated from ectopic lesions of patients with endometriosis

BACKGROUND

Research into the pathogenesis of endometriosis (EMs) would substantially promote its effective treatment and early diagnosis. However, the aetiology of EMs is poorly understood and controversial despite the progress in EMs research in the last several decades. Currently, accumulating evidence has shed light on the importance of endometrial stem cells (EnSCs) residing in the basal layer of endometrium in the establishment and progression of endometriotic lesions. Therefore, we aimed to identify the differences between EnSCs isolated from the ectopic lesions of EMs patients (EnSC-EM-EC) and EnSCs isolated from eutopic endometrium of control group (EnSC-Control). We further performed preliminary exploration of the potential signalling pathways involved in the above abnormalities.

METHODS

EnSC-EM-EC (n = 12) and EnSC-Control (n = 13) were successfully isolated. Then, the proliferative capacity, migratory capacity and angiogenic potential of EnSCs were evaluated by conventional MTT assay, flow cytometry, wound healing assay, transwell assay, tube formation assay and chick embryo chorioallantoic membrane assay respectively. The expression of 11 angiogenesis-associated biological factors and 11 cytokines secreted by EnSCs and 17 adhesion molecules expressed on EnSCs were determined by protein array assays respectively. Differentially expressed genes (DEGs) between EnSC-EM-EC and EnSC-Control were analysed by RNA-sequence.

RESULTS

EnSC-EM-EC exhibited unique biological characteristics, including prolonged mitosis, enhanced migratory capacity and enhanced angiogenic potential. Greater amounts of angiogenic factors (especially VEGF and PDGF) were secreted by EnSC-EM-EC than by EnSC-Control; however, the distinct profiles of cytokines secreted by EnSC-EM-EC and adhesion molecules expressed by EnSC-EM-EC require further investigation. A total of 523 DEGs between EnSC-EM-EC and EnSC-Control were identified and analysed using the KEGG and Gene Ontology databases.

CONCLUSIONS

Our results not only improve the understanding of EMs but also contribute to the development of EnSC-EM-EC as a tool for EMs drug discovery. These cells could be of great help in exploiting promising therapeutic targets and new biomarkers for EMs treatment and prognosis.

MicroRNAs in endometriosis: biological function and emerging biomarker candidates†

MicroRNAs (miRNAs), a class of small noncoding RNA molecules, have been recognized as key post-transcriptional regulators associated with a multitude of human diseases. Global expression profiling studies have uncovered hundreds of miRNAs that are dysregulated in several diseases, and yielded many candidate biomarkers. This review will focus on miRNAs in endometriosis, a common chronic disease affecting nearly 10% of reproductive-aged women, which can cause pelvic pain, infertility, and a myriad of other symptoms. Endometriosis has delayed time to diagnosis when compared to other chronic diseases, as there is no current accurate, easily accessible, and noninvasive tool for diagnosis. Specific miRNAs have been identified as potential biomarkers for this disease in multiple studies. These and other miRNAs have been linked to target genes and functional pathways in disease-specific pathophysiology. Highlighting investigations into the roles of tissue and circulating miRNAs in endometriosis, published through June 2018, this review summarizes new connections between miRNA expression and the pathophysiology of endometriosis, including impacts on fertility. Future applications of miRNA biomarkers for precision medicine in diagnosing and managing endometriosis treatment are also discussed.

Endometrial cells contribute to preexisting endometriosis lesions in a mouse model of retrograde menstruation†

Endometriosis is characterized by extrauterine growth of endometrial tissue accompanied by adverse clinical manifestations including chronic pelvic pain and infertility. Retrograde menstruation, the efflux of endometrium into the peritoneal cavity during menstruation, is believed to contribute to implantation of endometrial tissue and formation of endometriotic lesions at ectopic sites. While it is established through various rodent and nonhuman primate models that endometrial tissue fragments, as well as nondissociated stroma and glands, are capable of seeding endometriosis in a manner mimicking retrograde menstruation, the ability of single endometrial cells to participate in endometriotic processes has not been evaluated due to their failure to establish macroscopic endometriosis. We designed a model by which this capacity can be assessed by examining the integration of individual uterine cells into existing endometriosis lesions in mice. Endometriosis was induced in C57BL/6J female mice followed by intraperitoneal injection of GFP-labeled single uterine cells. We found that freshly introduced uterine cells can successfully integrate and contribute to various cell populations within the lesion. Strikingly, these cells also appeared to contribute to neo-angiogenesis and inflammatory processes within the lesion, which are commonly thought of as host-driven phenomena. Our findings underscore the potential of individual uterine cells to continuously expand lesions and participate in the progression of endometriosis. This model of retrograde menstruation may therefore be used to study processes involved in the pathophysiology of endometriosis.

The Effects of Anti-TGF-β1 on Epithelial-Mesenchymal Transition in the Pathogenesis of Adenomyosis

Adenomyosis is defined as the presence of endometrial glands and stroma in the myometrium. The mechanisms associated with the pathogenesis of adenomyosis remain unclear. Epithelial-mesenchymal transition (EMT) is characterized by losing cell polarity and cell-cell adhesion together with gaining migratory and invasive properties of stromal cells to become mesenchymal stem cells. Transforming growth factor-β1 (TGF-β1), an anti-inflammatory cytokine secreted by multiple cell types, plays a crucial role in embryogenesis and tissue homeostasis. The induction of EMT and ultimate fibrosis by TGF-β1 is suggested to play a critical role in the pathogenesis of adenomyosis. Thus, this study aims to demonstrate the occurrence of EMT in and the effects of anti-TGF-β1 on the pathogenesis of adenomyosis. ICR mice were fed with 1 μg/g body weight of tamoxifen (TAM) by in the first 4 postnatal days (PNDs). Subsequently, the right and left uterine horns were correspondingly injected with or without 10 μg of anti-TGF-β1 neutralizing antibody on PND42 followed by sacrifice on PND64. E-cadherin, vimentin, and α-smooth muscle actin (α-SMA) expression in the uteri was evaluated by qRT-PCR, Western blot, and immunohistochemistry. Clusters of endometrial glands and increased numbers of vimentin-positive stromal cells in the disrupted α-SMA-positive myometrium were observed in the uteri from TAM-treated mice. Numbers of stromal cells in the myometrium and the disrupted myometrial continuity were reduced by anti-TGF-β1. Moreover, uterine expression of E-cadherin and vimentin/α-SMA was increased and decreased by anti-TGF-β1 treatment, respectively. Anti-TGF-β1 successfully inhibits EMT and the development of adenomyosis in mouse uteri.

Abdominal wall sonography: a pictorial review

The anterior abdominal wall, which is composed of three layers (skin and adipose tissues; the myofascial layer; and the deep layer, consisting of the transversalis fascia, preperitoneal fat, and the parietal peritoneum), has many functions: containment, support and protection for the intraperitoneal contents, and involvement in movement and breathing. While hernias are often encountered and well reviewed in the literature, the other abdominal wall pathologies are less commonly described. In this pictorial review, we briefly discuss the normal anatomy of the anterior abdominal wall, describe the normal ultrasonographic anatomy, and present a wide range of pathologic abnormalities beyond hernias. Sonography emerges as the diagnostic imaging of first choice for assessing abdominal wall disorders, thus representing a valuable tool for ensuring appropriate management and limiting functional impairment.

Focused ultrasound for the diagnosis of non-palpable endometriotic lesions of the abdominal wall: a not-uncommon surgical complication

Endometriosis is a benign disease characterized by endometrial glands and stroma outside the endometrial cavity. We reported two cases of endometriosis of the abdominal wall, with subcutaneous and intramuscular localization, that became symptomatic a few years after a cesarean intervention. These cases have a clinical pattern quite similar to cutaneous endometriosis, but they are more difficult to diagnose through physical examination because they are barely palpable. In this sense, coupled with suggestive symptoms, ultrasound examination can confirm the clinical suspicion of endometriosis without the use of computed tomography and/or magnetic resonance imaging.

Expression of ALDH1A Isozymes in Human Endometrium with and without Endometriosis and in Ovarian Endometrioma

Human endometrium is a highly regenerative and dynamic tissue that undergoes cyclic changes during menstrual cycle. It has been reported that endometrial epithelium contains a population of progenitor/stem cells. Increasing amount of evidence indicates that progenitor/stem cells are involved in the pathogenesis of endometriosis. Proteins belonging to the aldehyde dehydrogenase 1 (ALDH1A) family have been reported to be markers of normal tissue stem cells and cancer stem cells. In this study, by using immunohistochemistry, we examined the expression of ALDH1A isozymes in human endometrial tissue, including that affected by endometriosis, and in ovarian endometrioma. Positive staining for ALDH1A isozymes was observed in the stroma of the endometrium and in endometriotic ovarian tissue. In the glands, expression patterns were distinct for different ALDH1A isozymes. ALDH1A1 and ALDH1A3 were highly expressed in the epithelium of stratum basalis of the endometrium and in the epithelium of ovarian endometrioma irrespective of the menstrual cycle, whereas ALDH1A2 was highly expressed only in the epithelium of endometrioma. Furthermore, ALDH1A1 co-localized with N-cadherin, which is a marker of endometrial epithelial progenitor cells, in the glands of stratum basalis. These findings support and reinforce the notion about the presence of progenitor/stem cells in endometrial glands in stratum basalis and in endometriotic glands, suggesting that these cells are involved in the physiology of the endometrium and in the pathology of endometriosis.

Effect of endometriosis on the fecal bacteriota composition of mice during the acute phase of lesion formation

Accumulating evidence indicates that there is an interaction between the gut microbiota and endometriotic lesions. The new formation of these lesions is associated with stem cell recruitment, angiogenesis and inflammation, which may affect the composition of the gut microbiota. To test this hypothesis, we herein induced endometriotic lesions by transplantation of uterine tissue fragments from green fluorescent protein (GFP)⁺ donor mice into the peritoneal cavity of GFP^- C57BL/6 wild-type mice. Sham-transplanted animals served as controls. Fecal pellets of the animals were collected 3 days before as well as 7 and 21 days after the induction of endometriosis to analyze the composition of the gut microbiota by means of 16S ribosomal RNA gene sequencing. The transplantation of uterine tissue fragments resulted in the establishment of endometriotic lesions in all analyzed mice. These lesions exhibited a typical histomorphology with endometrial glands surrounded by a vascularized stroma. Due to their bright GFP signal, they could be easily differentiated from the surrounding GFP^- host tissue. Bacterial 16S rRNA genes were successfully PCR-amplified from the DNA extracts of all obtained mice fecal samples. However, no significant effect of endometriosis induction on the composition of the bacterial microbiota was detected with our experimental setup. Our findings allow careful speculation that endometriosis in mice does not induce pronounced dysbiosis during the acute phase of lesion formation.

Rethinking mechanisms, diagnosis and management of endometriosis

Endometriosis is a chronic inflammatory disease defined as the presence of endometrial tissue outside the uterus, which causes pelvic pain and infertility. This disease should be viewed as a public health problem with a major effect on the quality of life of women as well as being a substantial economic burden. In light of the considerable progress with diagnostic imaging (for example, transvaginal ultrasound and MRI), exploratory laparoscopy should no longer be used to diagnose endometriotic lesions. Instead, diagnosis of endometriosis should be based on a structured process involving the combination of patient interviews, clinical examination and imaging. Notably, a diagnosis of endometriosis often leads to immediate surgery. Therefore, rethinking the diagnosis and management of endometriosis is warranted. Instead of assessing endometriosis on the day of the diagnosis, gynaecologists should consider the patient's 'endometriosis life'. Medical treatment is the first-line therapeutic option for patients with pelvic pain and no desire for immediate pregnancy. In women with infertility, careful consideration should be made regarding whether to provide assisted reproductive technologies prior to performing endometriosis surgery. Modern endometriosis management should be individualized with a patient-centred, multi-modal and interdisciplinary integrated approach.

IL-10 from plasmacytoid dendritic cells promotes angiogenesis in the early stage of endometriosis

An elevated level of IL‐10 has been considered a critical factor for the development of endometriosis; however, its detailed mechanism and causal relationship remain unclear. This study explored the cellular source and angiogenic activity of local IL‐10 during the early stage of endometriosis. Using a surgical murine model, we found that localised treatment with exogenous recombinant IL‐10 on the day of surgery significantly enhanced endometriotic lesion growth and angiogenesis, whereas blocking local IL‐10 activity using mAbs significantly suppressed those effects. Adoptive transfer of Il10^+/+ plasmacytoid dendritic cells into mice significantly enhanced lesion development, whereas Il10^−/− plasmacytoid dendritic cells significantly inhibited lesion development. Furthermore, in vitro angiogenesis analyses demonstrated that the IL‐10 and IL‐10 receptor pathway stimulated the migratory and tube formation ability of HUVECs as well as ectopic endometrial mesenchymal stem cells through, at least in part, a VEGF‐dependent pathway. We also found that recombinant IL‐10 directly stimulated angiogenesis, based on a Matrigel plug assay as well as a zebrafish model. Pathological results from human endometrioma tissues showed the increased infiltration of CD123⁺ plasmacytoid dendritic cells and higher percentages of cells that express the IL‐10 receptor and CD31 as compared with the corresponding normal counterparts. Taken together, these results show that IL‐10 secreted from local plasmacytoid dendritic cells promotes endometriosis development through pathological angiogenesis during the early disease stage. This study provides a scientific basis for a potential therapeutic strategy targeting the IL‐10—IL‐10 receptor pathway in the endometriotic milieu. © 2019 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Knockdown of vascular cell adhesion molecule 1 impedes transforming growth factor beta 1-mediated proliferation, migration, and invasion of endometriotic cyst stromal cells

PURPOSE

Endometriosis is one of the most common, difficult, and complicated gynecological disorders. Vascular cell adhesion molecule 1 (VCAM-1) has been reported to be aberrantly expressed in patients with endometriosis. However, the exact role and mechanism of VCAM-1 in endometriosis remains unclear.

METHODS

The expression of transforming growth factor beta 1 (TGF-β1) and VCAM-1 was determined by quantitative real-time polymerase chain reaction and western blotting. Human endometriotic cells were cultured and their responsiveness to TGF-β1 was evaluated by Cell Counting Kit-8, 5-ethynyl-2'-deoxyuridine, and transwell migration and invasion assays.

RESULTS

The levels of TGF-β1 and VCAM-1 mRNA were upregulated in the endometriotic tissues. Knockdown of TGF-β1 in endometriotic cyst stromal cells caused a marked inhibition of cell proliferation, migration, and invasion. Treatment of endometriotic cyst stromal cells with TGF-β1 resulted in an obvious promotion of cell proliferation, migration, and invasion, and strikingly increased the protein expression of VCAM-1. Silencing of Smad3 abated TGF-β1-stimulated VCAM-1 expression. Furthermore, the promoting effects of TGF-β1 on the proliferation, migration, and invasion of endometriotic cyst stromal cells were blocked by silencing of VCAM-1.

CONCLUSION

Knockdown of VCAM-1 impedes TGF-β1-mediated proliferation, migration, and invasion of endometrial cells, thereby indicating that VCAM-1 may serve as a therapeutic target for endometriosis.

Endometriosis

Pelvic endometriosis is a complex syndrome characterized by an estrogen-dependent chronic inflammatory process that affects primarily pelvic tissues, including the ovaries. It is caused when shed endometrial tissue travels retrograde into the lower abdominal cavity. Endometriosis is the most common cause of chronic pelvic pain in women and is associated with infertility. The underlying pathologic mechanisms in the intracavitary endometrium and extrauterine endometriotic tissue involve defectively programmed endometrial mesenchymal progenitor/stem cells. Although endometriotic stromal cells, which compose the bulk of endometriotic lesions, do not carry somatic mutations, they demonstrate specific epigenetic abnormalities that alter expression of key transcription factors. For example, GATA-binding factor-6 overexpression transforms an endometrial stromal cell to an endometriotic phenotype, and steroidogenic factor-1 overexpression causes excessive production of estrogen, which drives inflammation via pathologically high levels of estrogen receptor-β. Progesterone receptor deficiency causes progesterone resistance. Populations of endometrial and endometriotic epithelial cells also harbor multiple cancer driver mutations, such as KRAS, which may be associated with the establishment of pelvic endometriosis or ovarian cancer. It is not known how interactions between epigenomically defective stromal cells and the mutated genes in epithelial cells contribute to the pathogenesis of endometriosis. Endometriosis-associated pelvic pain is managed by suppression of ovulatory menses and estrogen production, cyclooxygenase inhibitors, and surgical removal of pelvic lesions, and in vitro fertilization is frequently used to overcome infertility. Although novel targeted treatments are becoming available, as endometriosis pathophysiology is better understood, preventive approaches such as long-term ovulation suppression may play a critical role in the future.

Adipocyte alterations in endometriosis: reduced numbers of stem cells and microRNA induced alterations in adipocyte metabolic gene expression

BACKGROUND

Endometriosis is an estrogen dependent, inflammatory disorder occurring in 5-10% of reproductive-aged women. Women with endometriosis have a lower body mass index (BMI) and decreased body fat compared to those without the disease, yet few studies have focused on the metabolic abnormalities in adipose tissue in women with endometriosis. Previously, we identified microRNAs that are differentially expressed in endometriosis and altered in the serum of women with the disease. Here we explore the effect of endometriosis on fat tissue and identified a role for endometriosis-related microRNAs in fat metabolism and a reduction in adipocyte stem cell number.

METHODS

Primary adipocyte cells cultured from 20 patients with and without endometriosis were transfected with mimics and inhibitors of microRNAs 342-3p or Let 7b-5p to model the status of these microRNAs in endometriosis. RNA was extracted for gene expression analysis by qRT-PCR. PCNA expression was used as a marker of adipocyte proliferation. Endometriosis was induced experimentally in 9-week old female C57BL/6 mice and after 10 months fat tissue was harvested from both the subcutaneous (inguinal) and visceral (mesenteric) tissue. Adipose-derived mesenchymal stem cells in fat tissue were characterized in both endometriosis and non-endometriosis mice by FACS analysis.

RESULTS

Gene expression analysis showed that endometriosis altered the expression of Cebpa, Cebpb, Ppar-γ, leptin, adiponectin, IL-6, and HSL, which are involved in driving brown adipocyte differentiation, appetite, insulin sensitivity and fat metabolism. Each gene was regulated by an alteration in microRNA expression known to occur in endometriosis. Analysis of the stem cell content of adipose tissue in a mouse model of endometriosis demonstrated a reduced number of adipocyte stem cells.

CONCLUSIONS

We demonstrate that microRNAs Let-7b and miR-342-3p affected metabolic gene expression significantly in adipocytes of women with endometriosis. Similarly, there is a reduction in the adipose stem cell population in a mouse model of endometriosis. Taken together these data suggest that endometriosis alters BMI in part through an effect on adipocytes and fat metabolism.

Micrometastasis of endometriosis to distant organs in a murine model

Endometriosis is an inflammatory gynecological disorder among reproductive-aged women caused by the engraftment and proliferation of endometrial cells outside the uterus, most commonly in the pelvis. It is thought that the disease arises primarily from retrograde menstruation where cells from the endometrium travel through the fallopian tubes to the peritoneal cavity. However, migration of endometriosis-derived cells to distant organs outside of the peritoneal cavity have not been explored. In the present study, we developed and validated a mouse model of disseminated endometriosis using syngeneic DsRed endometrial tissue introduced into the peritoneum of immunocompetent mice. Flow cytometry and immunofluorescence analysis, demonstrated the presence of endometriosis-derived cells in multiple organs (including lung, spleen, liver and brain) in the murine endometriosis model. Immunostaining revealed the presence of DsRed+/CD45- cells in brain, liver and lung. Engraftment occurred in all experimental animals examined. Cells from endometriotic lesions are capable of migration to and engraftment of multiple organs outside of the peritoneal cavity. Micrometastasis of endometriosis is a novel and frequent phenomenon. These data suggest that widespread dissemination of endometriosis may be common, clinically unrecognized and contribute to the diffuse clinical manifestations of this disease.

TGR5 agonist INT-777 mitigates inflammatory response in human endometriotic stromal cells: A therapeutic implication for endometriosis

Endometriosis is a condition characterized by the presence of endometrial tissues outside the uterus. Endometriotic stromal cells (ESCs) are known to undergo regeneration and are linked to the causation of endometriosis. Activation of stromal cells by local inflammatory cytokines is proposed to be one of the mechanisms of endometriosis development. Takeda-G-protein-receptor-5 (TGR5) is a G protein-coupled bile acid receptor that plays multiple roles in various cells and tissues. In this study, we show that activation of TGR5 by its specific agonist, INT-777, protects ESCs from inflammation and oxidative stress induced by tumor necrosis factor-α (TNF-α). TGR5 is fairly expressed in cultured ESCs, and TNF-α treatment suppresses TGR5 expression. Activation of TGR5 by its synthetic agonist, INT-777, dramatically reduces the production of pro-inflammatory cytokines and adhesion molecules by TNF-α, including interleukin-6 (IL-6), interleukin-8 (IL-8), monocyte chemoattractant protein-1 (MCP-1), intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). Moreover, INT-777 suppresses TNF-α-induced NADPH oxidase 4 (NOX4) expression and ameliorates cellular oxidative stress. Mechanistically, our findings demonstrate that INT-777 suppresses TNF-α-induced c-Jun N-terminal kinase (JNK) activation via suppression of p-JNK. INT-777 inhibits TNF-α-induced activation of the activator protein-1 (AP-1) pathway owing to its suppression of c-Jun and c-fos as well as transfected AP-1 promoter. INT-777 also inhibits nuclear factor-κB (NF-κB) activation as revealed by its suppression of TNF-α-induced nuclear p65 accumulation and NF-κB promoter. Collectively, our data indicate that activation of TGR5 by its agonist has protective effects against inflammation and reactive oxygen species (ROS) in cytokine-induced activation of ESCs. Therefore, INT-777 may have an implication in the clinical treatment of endometriosis.