Endometrial stem/progenitor cells and their role in the pathogenesis of endometriosis

Endoplasmic reticulum stress of endometrial mesenchymal stem cells in endometriosis

OBJECTIVE

The human endometrium has significant regenerative abilities due to stem cells, which are vital in immunomodulation, immune tolerance, steroid hormone response, and inflammation. Endometriosis, an inflammatory gynecological disorder where endometrium-like tissue grows outside uterus, affects millions of women and often causes infertility. Recent research indicates that stem cells contribute to pathology of endometriosis. ER stress is implicated in various diseases, including endometriosis. This study aims to examine ER stress in eMSCs within endometriosis pathogenesis and uncover underlying disease mechanisms.

METHODS

Samples were collected from healthy subjects and women with endometriosis in both proliferative and secretory phases. eMSCs were isolated and characterized via flow cytometry. ER stress protein levels were assessed using proteomic analysis, with validation through Western Blot and immunofluorescence staining. Gene expression was analyzed by RT-qPCR, and ultrastructural examination of eMSCs was conducted using TEM. ER stress markers in tissue samples were detected in SUSD2+ eMSCs through immunofluorescence staining and visualized using a confocal microscope. Statistical analysis was performed using SPSS program.

RESULTS

The proteomics analysis uncovered ER stress-related proteins (DDRGK1, RTN3, ERp44, TMED2, TMEM33, TMX3) whose levels were significantly distinct from control group. Western Blot analysis and immunofluorescence staining results at protein level; RT-qPCR results at gene level supported these findings. TEM analysis also showed ultrastructural presence of ER stress in endometriosis groups.

CONCLUSION

Presence of ER stress in eMSCs in pathogenesis of endometriosis has been demonstrated using various methods. Our research has potential to shed light on pathology of endometriosis and offer promising avenues for non-invasive diagnosis and potential treatment.

Wenshen Xiaozheng Tang alleviates fibrosis in endometriosis by regulating differentiation and paracrine signaling of endometrium-derived mesenchymal stem cells

ETHNOPHARMACOLOGICAL RELEVANCE

Wenshen Xiaozheng Tang (WXT), a traditional Chinese medicine (TCM) decoction, is effective for treating endometriosis. However, the effect of WXT on endometrium-derived mesenchymal stem cells (eMSCs) which play a key role in the fibrogenesis of endometriosis requires further elucidation.

AIMS OF THE STUDY

The aim of this study was to clarify the potential mechanism of WXT in improving fibrosis in endometriosis by investigating the regulation of WXT on differentiation and paracrine of eMSCs.

MATERIALS AND METHODS

The nude mice with endometriosis were randomly divided into model group, WXT group and mifepristone group. After 21 days of treatment, the lesion volume was calculated. Fibrosis in the lesions was evaluated by Masson staining and expression of fibrotic proteins. The differentiation of eMSCs in vivo was explored using a fate-tracking experiment. To further clarify the regulation of WXT on eMSCs, primary eMSCs from the ectopic lesions of endometriosis patients were isolated and characterized. The effect of WXT on the proliferation and differentiation of ectopic eMSCs was examined. To evaluate the role of WXT on the paracrine activity of ectopic eMSCs, the conditioned medium (CM) from ectopic eMSCs pretreated with WXT was collected and applied to treat ectopic endometrial stromal cells (ESCs), after which the expression of fibrotic proteins in ectopic ESCs was assessed. In addition, transcriptome sequencing was used to investigate the regulatory mechanism of WXT on ectopic eMSCs, and western blot and ELISA were employed to determine the key mediator.

RESULTS

WXT impeded the growth of ectopic lesions in nude mice with endometriosis and reduced collagen deposition and the expression of fibrotic proteins fibronectin, collagen I, α-SMA and CTGF in the endometriotic lesions. The fate-tracking experiment showed that WXT prevented human eMSCs from differentiating into myofibroblasts in the nude mice. We successfully isolated eMSCs from the lesions of patients with endometriosis and demonstrated that WXT suppressed proliferation and myofibroblast differentiation of ectopic eMSCs. Moreover, the expression of α-SMA, collagen I, fibronectin and CTGF in ectopic ESCs was significantly down-regulated by the CM of ectopic MSCs pretreated with WXT. Combining the results of RNA sequencing, western blot and ELISA, we found that WXT not only reduced thrombospondin 4 expression in ectopic eMSCs, but also decreased thrombospondin 4 secretion from ectopic eMSCs. Thrombospondin 4 concentration-dependently upregulated the expression of collagen I, fibronectin, α-SMA and CTGF in ectopic ESCs, indicating that thrombospondin 4 was a key mediator of WXT in inhibiting the fibrotic process in endometriosis.

CONCLUSION

WXT improved fibrosis in endometriosis by regulating differentiation and paracrine signaling of eMSCs. Thrombospondin 4, whose release from ectopic eMSCs is inhibited by WXT, may be a potential target for the treatment of endometriosis.

Endometriotic lesions exhibit distinct metabolic signature compared to paired eutopic endometrium at the single-cell level

Current therapeutics of endometriosis focus on hormonal disruption of endometriotic lesions (ectopic endometrium, EcE). Recent findings show higher glycolysis utilization in EcE, suggesting non-hormonal strategy for disease treatment that addresses cellular metabolism. Identifying metabolically altered cell types in EcE is important for targeted metabolic drug therapy without affecting eutopic endometrium (EuE). Here, using single-cell RNA-sequencing, we examine twelve metabolic pathways in paired samples of EuE and EcE from women with confirmed endometriosis. We detect nine major cell types in both EuE and EcE. Metabolic pathways are most differentially regulated in perivascular, stromal, and endothelial cells, with the highest changes in AMPK signaling, HIF-1 signaling, glutathione metabolism, oxidative phosphorylation, and glycolysis. We identify transcriptomic co-activation of glycolytic and oxidative metabolism in perivascular and stromal cells of EcE, indicating a critical role of metabolic reprogramming in maintaining endometriotic lesion growth. Perivascular cells, involved in endometrial stroma repair and angiogenesis, may be potential targets for non-hormonal treatment of endometriosis.

The pathogenesis of endometriosis and adenomyosis: insights from single-cell RNA sequencing†

Endometriosis and adenomyosis are two similar gynecological diseases that are characterized by ectopic implantation and the growth of the endometrial tissue. Previous studies have reported that they share a common pathophysiology in some respects, such as a similar cellular composition and resistance to the progestogen of lesions, but their underlying mechanisms remain elusive. Emerging single-cell ribonucleic acid sequencing (scRNA-seq) technologies allow for the dissection of single-cell transcriptome mapping to reveal the etiology of diseases at the level of the individual cell. In this review, we summarized the published findings in research on scRNA-seq regarding the cellular components and molecular profiles of diverse lesions. They show that epithelial cell clusters may be the vital progenitors of endometriosis and adenomyosis. Subclusters of stromal cells, such as endometrial mesenchymal stem cells and fibroblasts, are also involved in the occurrence of endometriosis and adenomyosis, respectively. Moreover, CD8+ T cells, natural killer cells, and macrophages exhibit a deficiency in clearing the ectopic endometrial cells in the immune microenvironment of endometriosis. It seems that the immune responses are activated in adenomyosis. Understanding the immune characteristics of adenomyosis still needs further exploration. Finally, we discuss the application of findings from scRNA-seq for clinical diagnosis and treatment. This review provides fresh insights into the pathogenesis of endometriosis and adenomyosis as well as the therapeutic targets at the cellular level.

Is Neonatal Uterine Bleeding Involved in Early-Onset Endometriosis?

BACKGROUND

There has been considerable progress in our understanding of endometriosis, but its pathophysiology remains uncertain. Uncovering the underlying mechanism of the rare instances of endometriosis reported in early postmenarcheal years and in girls before menarche can have wide implications.

METHODS

We conducted a literature review of all relevant articles on Medline.

RESULTS

In the review, we explore the pathogenetic theories of premenarcheal endometriosis, the role of retrograde menstruation in the adult and its potential role in early-onset disease, as well as the factors that argue against the existence of a link between early-onset endometriosis (EOE) and neonatal uterine bleeding (NUB).

CONCLUSIONS

As with endometriosis in adult women, the pathogenesis of early-onset disease remains unclear. A link between NUB and EOE is plausible, but there are considerable challenges to collating supporting evidence. The state of our understanding of early uterine development and of the pathophysiology of NUB leaves many unknowns that need exploration. These include proof of the existence of viable endometrial cells or endometrial mesenchymal stem cells in NUB, their passage to the pelvic cavity, their possible response to steroids, and whether they can reside within the pelvic cavity and remain dormant till menarche.

[Holistic treatment of endometriosis]

BACKGROUND

The pain phenomena caused by endometriosis are manifold. In addition to nociceptive pain there is also a nociplastic reaction with central sensitization. Atypical symptoms, such as acyclic lower abdominal pain, radiating pain, nonspecific bladder and intestinal complaints or even depression increasingly occur in addition to the classical cyclic complaints, such as severe dysmenorrhea, cyclic lower abdominal pain, dyspareunia, dysuria and dyschezia. Due to the diffuse range of symptoms, affected patients often consult not just gynecologists but also specialists from other disciplines (internal medicine, gastroenterology, orthopedics, pain therapy, psychology etc.).

OBJECTIVE

The complexity of endometriosis is presented. The resulting approaches to multimodal interdisciplinary holistic treatment are described.

RESULTS

Interdisciplinary concepts should be involved in the optimal treatment of endometriosis patients along with hormonal and surgical treatment, mostly under the supervision of a gynecologist and pain management, dietary changes, psychological support and physiotherapeutic management should also be included. This article provides an overview of possible treatment strategies for chronic symptomatic endometriosis.

CONCLUSION

Based on multimodal treatment strategies and regarding the complex pathophysiological alterations of this disease, the complex complaints that significantly impair the quality of life of endometriosis patients can be greatly improved.

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.

Co-Existence of Endometriosis with Ovarian Dermoid Cysts: A Retrospective Cohort Study

Both endometriosis and ovarian dermoid cysts are benign conditions characterized by the presence of well-differentiated tissues in ectopic locations. The presence and surgical excision of these entities can potentially impact ovarian reserves, contributing to reduced chances of future pregnancy. The objective of our study is to investigate the bidirectional association between endometriosis and ovarian dermoid cysts, as well as to analyze the clinical characteristics of patients diagnosed with both conditions. A retrospective cohort study was conducted, including women who underwent laparoscopy and received histological diagnoses of endometriosis and/or dermoid cysts between 2011 and 2019 at the Cantonal Hospital of Schaffhausen. We identified 985 women with endometriosis and 83 women with ovarian dermoid cysts. Among these groups, 22 women presented with both endometriosis and ovarian dermoid cysts. The majority of the above patients had endometriosis stage rASRM I-II (72.7%), with peritoneal endometriosis being the most common phenotype of endometriosis (77.2%). Out of the 14 patients with a desire for future pregnancy, the majority (11/14, 78.5%) had an EFI score of 7-8. The prevalence of bilateral ovarian dermoid cysts was higher in women with both ovarian dermoid cysts and endometriosis in comparison to women with ovarian dermoid cysts without endometriosis (18% vs. 6.5%). Our study revealed that 26.5% of women with ovarian dermoid cysts also had endometriosis, a notably higher prevalence than observed in the general population. Clinicians should be aware of this co-existence, and preoperative counseling should be an integral part of the care plan for affected individuals, where the potential risks and the available options for fertility preservation should be discussed in detail.

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.

Is neonatal uterine bleeding responsible for early-onset endometriosis?

BACKGROUND

It has been hypothesized that the origin of early-onset endometriosis could be from endometrial mesenchymal stem cells (eMSCs) in neonatal uterine blood (NUB). There is no information on the possible mechanistic basis linking an association between NUB/neonatal endometrium and development of early-onset endometriosis. In this study we performed a series of experiments to clarify the mechanistic link between NUB and/or neonatal endometrium and development of early-onset endometriosis.

METHODS

We retrospectively collected postmortem neonatal endometria (n = 15) and prospectively collected NUB (n = 18) of female babies for the analysis of different biological markers including eMSCs. Immunohistochemical analysis of neonatal endometria was performed to examine the expression patterns of ovarian steroid receptors (ER/PGR), decidualization (prolactin, IGFBP1), pre-decidualization (Glycodelin A, α-SMA), proliferation (Ki-67 index), vascularity (CD31 + cells), immunocompetent CD68+, CD45+, CD56 + cells and some putative markers of eMSCs. Cell transfer method and immunocytochemistry were used to investigate the eMSCs and/or endometrial cells in NUB.

RESULTS

Immunohistochemical analysis of postmortem neonatal endometria revealed variable staining response to ER/PGR, decidual markers, and substantial proliferative and angiogenic activity. A moderate to strong immunoexpression of Glycodelin-A was found in both neonatal and adult endometria. The tissue infiltration of CD56+, CD45 + and CD68 + immunocompetent cells was significantly low in neonatal endometria than that in adult endometria (p = 0.0003, p < 0.0001, p = 0.034, respectively). No eMSCs or even endometrial cells were detected in NUB. However, a variable expression of some phenotypes of eMSCs (CD90/CD105) was found in neonatal endometria.

CONCLUSIONS

Based on our serial experiments we did not find any supporting evidence for the role of NUB in early-onset endometriosis. Neonatal endometria showed variable expression of ovarian steroid receptors, decidualization, and a substantial amount of proliferative and angiogenic activity. As an alternative mechanism, a significantly less tissue accumulation of immunocompetent cells in neonatal endometria may explain the survival of ER + and PGR + cells should they make entry into the pelvis and consequent development of early endometriosis with the onset of ovarian function. Future study with large sample size and application of modified technological tools is warranted to test the NUB hypothesis and to clarify their biological or clinical significance.

TRIAL REGISTRATION

not applicable.

Fusobacterium infection facilitates the development of endometriosis through the phenotypic transition of endometrial fibroblasts

Retrograde menstruation is a widely accepted cause of endometriosis. However, not all women who experience retrograde menstruation develop endometriosis, and the mechanisms underlying these observations are not yet understood. Here, we demonstrated a pathogenic role of Fusobacterium in the formation of ovarian endometriosis. In a cohort of women, 64% of patients with endometriosis but <10% of controls were found to have Fusobacterium infiltration in the endometrium. Immunohistochemical and biochemical analyses revealed that activated transforming growth factor-β (TGF-β) signaling resulting from Fusobacterium infection of endometrial cells led to the transition from quiescent fibroblasts to transgelin (TAGLN)-positive myofibroblasts, which gained the ability to proliferate, adhere, and migrate in vitro. Fusobacterium inoculation in a syngeneic mouse model of endometriosis resulted in a marked increase in TAGLN-positive myofibroblasts and increased number and weight of endometriotic lesions. Furthermore, antibiotic treatment largely prevented establishment of endometriosis and reduced the number and weight of established endometriotic lesions in the mouse model. Our data support a mechanism for the pathogenesis of endometriosis via Fusobacterium infection and suggest that eradication of this bacterium could be an approach to treat endometriosis.

Beclin-1-dependent autophagy, but not apoptosis, is critical for stem-cell-mediated endometrial programming and the establishment of pregnancy

The human endometrium shows a remarkable regenerative capacity that enables cyclical regeneration and remodeling throughout a woman's reproductive life. Although early postnatal uterine developmental cues direct this regeneration, the vital factors that govern early endometrial programming are largely unknown. We report that Beclin-1, an essential autophagy-associated protein, plays an integral role in uterine morphogenesis during the early postnatal period. We show that conditional depletion of Beclin-1 in the uterus triggers apoptosis and causes progressive loss of Lgr5+/Aldh1a1+ endometrial progenitor stem cells, with concomitant loss of Wnt signaling, which is crucial for stem cell renewal and epithelial gland development. Beclin-1 knockin (Becn1 KI) mice with disabled apoptosis exhibit normal uterine development. Importantly, the restoration of Beclin-1-driven autophagy, but not apoptosis, promotes normal uterine adenogenesis and morphogenesis. Together, the data suggest that Beclin-1-mediated autophagy acts as a molecular switch that governs the early uterine morphogenetic program by maintaining the endometrial progenitor stem cells.

Detention and mapping of iron and toxic environmental elements in human ovarian endometriosis: A suggested combined role

BACKGROUND

Endometriosis is a disease affecting 10-15 % of women worldwide, consisting in the ectopic growth of endometrial cells outside the uterine cavity. Whist the pathogenetic mechanisms of endometriosis remain elusive and contemplating even environmental causes, iron deposits are common in endometrial lesions, indicating an altered iron metabolism at this level. This study was undertaken to reveal a possible relationship between iron dysmetabolism and accumulation of environmental metals.

METHODS

By combining histological and histochemical analysis (H&E and Perl's staining) with μ- and nano- synchrotron-based (SR-based) X-ray Fluorescence (XRF) microscopy, we investigated the distribution of iron and other elements in the ovarian endometriomas of 12 endometriosis patients and in 7 healthy endometrium samples.

RESULTS

XRF microscopy expanded the findings obtained by Perl's staining, revealing with an exceptional sensitivity intracellular features of iron accumulation in the epithelial endometrium, stroma and macrophages of the endometriotic lesions. XRF evidenced that iron was specifically accumulated in multiple micro aggregates, reaching concentrations up to 10-20 % p/p. Moreover, by XRF analysis we revealed for the first time the retention of a number of exogenous and potentially toxic metals such as Pb, Br, Ti, Al Cr, Si and Rb partially or totally co-localizing with iron.

CONCLUSION

μXRF reveals accumulation and colocalization of iron and environmental metals in human ovarian endometriosis, suggesting a role in the pathogenesis of endometriosis.

Archimetrosis: the evolution of a disease and its extant presentation : Pathogenesis and pathophysiology of archimetrosis (uterine adenomyosis and endometriosis)

PURPOSE

This article presents a novel concept of the evolution and, thus, the pathogenesis of uterine adenomyosis as well as peritoneal and peripheral endometriosis. Presently, no unifying denomination of this nosological entity exists.

METHODS

An extensive search of the literature on primate evolution was performed. This included comparative functional morphology with special focus on the evolution of the birthing process that fundamentally differs between the haplorrhine primates and most of the other eutherian mammals. The data were correlated with the results of own research on the pathophysiology of human archimetrosis and with the extant presentation of the disease.

RESULTS

The term Archimetrosis is suggested as a denomination of the nosological entity. Archimetrosis occurs in human females and also in subhuman primates. There are common features in the reproductive process of haplorrhine primates such as spontaneous ovulation and corpus luteum formation, spontaneous decidualization and menstruation. These have fused Müllerian ducts resulting in a uterus simplex. Following a usually singleton pregnancy, the fetus is delivered in the skull position. Some of these features are shared by other mammals, but not in that simultaneous fashion. In haplorrhine primates, with the stratum vasculare, a new myometrial layer has evolved during the time of the Cretaceous-Terrestrial Revolution (KTR) that subserves expulsion of the conceptus and externalization of menstrual debris in non-conceptive cycles. Hypercontractility of this layer has evolved as an advantage with respect to the survival of the mother and the birth of a living child during delivery and may be experienced as primary dysmenorrhea during menstruation. It may result in tissue injury by the sheer power of the contractions and possibly by the associated uterine ischemia. Moreover, the lesions at extra-uterine sites appear to be maintained by biomechanical stress.

CONCLUSIONS

Since the pathogenesis of archimetrosis is connected with the evolution of the stratum vasculare, tissue injury and repair (TIAR) turns out to be the most parsimonious explanation for the development of the disease based on clinical, experimental and evolutionary evidence. Furthermore, a careful analysis of the published clinical data suggests that, in the risk population with uterine hypercontractility, the disease develops with a yet to be defined latency phase after the onset of the biomechanical injury. This opens a new avenue of prevention of the disease in potentially affected women that we consider to be primarily highly fertile.

The Emerging Role of Menstrual-Blood-Derived Stem Cells in Endometriosis

The human endometrium has a complex cellular composition that is capable of promoting cyclic regeneration, where endometrial stem cells play a critical role. Menstrual blood-derived stem cells (MenSC) were first discovered in 2007 and described as exhibiting mesenchymal stem cell properties, setting them in the spotlight for endometriosis research. The stem cell theory for endometriosis pathogenesis, supported by the consensual mechanism of retrograde menstruation, highlights the recognized importance that MenSC have gained by potentially being directly related to the genesis, development and maintenance of ectopic endometriotic lesions. Meanwhile, the differences observed between MenSC in patients with endometriosis and in healthy women underlines the applicability of these cells as a putative biomarker for the early diagnosis of endometriosis, as well as for the development of targeted therapies. It is expected that in the near future MenSC will have the potential to change the way we manage this complex disease, once their long-term safety and effectiveness are assessed.

Pathophysiology, diagnosis, and management of endometriosis

Endometriosis affects approximately 190 million women and people assigned female at birth worldwide. It is a chronic, inflammatory, gynecologic disease marked by the presence of endometrial-like tissue outside the uterus, which in many patients is associated with debilitating painful symptoms. Patients with endometriosis are also at greater risk of infertility, emergence of fatigue, multisite pain, and other comorbidities. Thus, endometriosis is best understood as a condition with variable presentation and effects at multiple life stages. A long diagnostic delay after symptom onset is common, and persistence and recurrence of symptoms despite treatment is common. This review discusses the potential genetic, hormonal, and immunologic factors that lead to endometriosis, with a focus on current diagnostic and management strategies for gynecologists, general practitioners, and clinicians specializing in conditions for which patients with endometriosis are at higher risk. It examines evidence supporting the different surgical, pharmacologic, and non-pharmacologic approaches to treating patients with endometriosis and presents an easy to adopt step-by-step management strategy. As endometriosis is a multisystem disease, patients with the condition should ideally be offered a personalized, multimodal, interdisciplinary treatment approach. A priority for future discovery is determining clinically informative sub-classifications of endometriosis that predict prognosis and enhance treatment prioritization.

Preparation and In Vitro Osteogenic Evaluation of Biomimetic Hybrid Nanocomposite Scaffolds Based on Gelatin/Plasma Rich in Growth Factors (PRGF) and Lithium-Doped 45s5 Bioactive Glass Nanoparticles

Bone tissue engineering is an emerging technique for repairing large bone lesions. Biomimetic techniques expand the use of organic-inorganic spongy-like nanocomposite scaffolds and platelet concentrates. In this study, a biomimetic nanocomposite scaffold was prepared using lithium-doped bioactive-glass nanoparticles and gelatin/PRGF. First, sol-gel method was used to prepare bioactive-glass nanoparticles that contain 0, 1, 3, and 5%wt lithium. The lithium content was then optimized based on antibacterial and MTT testing. By freeze-drying, hybrid scaffolds comprising 5, 10, and 20% bioglass were made. On the scaffolds, human endometrial stem cells (hEnSCs) were cultured for adhesion (SEM), survival, and osteogenic differentiation. Alkaline phosphatase activity and osteopontin, osteocalcin, and Runx2 gene expression were measured. The effect of bioactive-glass nanoparticles and PRGF on nanocomposites' mechanical characteristics and glass-transition temperature (T _g) was also studied. An optimal lithium content in bioactive glass structure was found to be 3% wt. Nanoparticle SEM examination indicated grain deformation due to different sizes of lithium and sodium ions. Results showed up to 10% wt bioactive-glass and PRGF increased survival and cell adhesion. Also, Hybrid scaffolds revealed higher ALP-activity and OP, OC, and Runx2 gene expression. Furthermore, bioactive-glass has mainly increased ALP-activity and Runx2 expression, whereas PRGF increases the expression of OP and OC genes. Bioactive-glass increases scaffold modulus and T _g continuously. Hence, the presence of both bioactive-glass and nanocomposite scaffold improves the expression of osteogenic differentiation biomarkers. Subsequently, it seems that hybrid scaffolds based on biopolymers, Li-doped bioactive-glass, and platelet extracts can be a good strategy for bone repair.

Spatial expression of the FGFR2b splice isoform and its prognostic significance in endometrioid endometrial carcinoma

Endometrial carcinoma (EC) is the most common gynecological malignancy and fibroblast growth factor receptor 2 (FGFR2) is a frequently dysregulated receptor tyrosine kinase. FGFR2b and FGFR2c are the two main splice isoforms of FGFR2 and are normally localized in epithelial and mesenchymal cells, respectively. Previously, we demonstrated that FGFR2c mRNA expression was associated with aggressive tumor characteristics, shorter progression-free survival (PFS), and disease-specific survival (DSS) in endometrioid ECs (EECs). The objectives of this study were to investigate the spatial expression of FGFR2b in normal and hyperplasia with and without atypia of human endometrium and to assess the prognostic significance of FGFR2b expression in EC. FGFR2b and FGFR2c mRNA expression was evaluated in normal (proliferative [n = 10], secretory [n = 15], and atrophic [n = 10] endometrium), hyperplasia with and without atypia (n = 19) as well as two patient cohorts of EC samples (discovery [n = 78] and Vancouver [n = 460]) using isoform-specific BaseScope RNA in situ hybridization assays. Tumors were categorized based on FGFR2 isoform expression (one, both, or neither) and categories were correlated with clinicopathologic markers, molecular subtypes, and clinical outcomes. The FGFR2b splice isoform was exclusively expressed in the epithelial compartment of normal endometrium and hyperplasia without atypia. We observed FGFR2c expression at the basalis layer of glands in 33% (3/9) of hyperplasia with atypia. In patients with EEC, FGFR2b+/FGFR2c- expression was found in 48% of the discovery cohort and 35% of the validation Vancouver cohort. In univariate analyses, tumors with FGFR2b+/FGFR2c- expression had longer PFS (hazard ratio [HR] 0.265; 95% CI 0.145-0.423; log-rank p < 0.019) and DSS (HR 0.31; 95% CI 0.149-0.622; log-rank p < 0.001) compared to tumors with FGFR2b-/FGFR2c+ expression in the large EEC Vancouver cohort. In multivariable Cox regression analyses, tumors with FGFR2b+/FGFR2c- expression were significantly associated with longer DSS (HR 0.37; 95% CI 0.153-0.872; log-rank p < 0.023) compared to FGFR2b-/FGFR2c+ tumors. In conclusion, FGFR2b+/FGFR2c- expression is associated with favorable clinicopathologic markers and clinical outcomes suggesting that FGFR2b could play a role in tailoring the management of EEC patients in the clinic if these findings are confirmed in an independent cohort.

Expression of Fucosyltransferase 4 (FUT4) mRNA Is Increased in Endometrium from Women with Endometriosis

Endometriosis is a common gynecological disorder defined as the presence of endometrial-like tissue (glands and stroma) outside the uterus. The etiopathogenesis of endometriosis is still poorly recognized. It is speculated that stage-specific embryonic antigen 1 (SSEA-1)-positive stem-like glandular epithelial cells may contribute to the development of the disease. The synthesis of SSEA-1 is mediated by fucosyltransferase 4 encoded by the FUT4 gene. Therefore, this study aimed to evaluate the specific expression of FUT4 mRNA in biopsies of the endometrium from women with and without endometriosis. FUT4 mRNA levels were examined in 49 women with laparoscopically confirmed endometriosis and 28 controls by means of quantitative reverse-transcription polymerase chain reaction (qRT-PCR). The expression of FUT4 mRNA was significantly increased in the endometrium of patients with endometriosis when compared to the controls (p < 0.0001). Expression of FUT4 mRNA in the endometrium was correlated with the severity of endometriosis (rs = 0.5579, p < 0.0001); however, there were no differences in endometrial FUT4 mRNA expression when comparing endometriotic lesions from various locations. The discriminatory ability of FUT4 mRNA expression was evaluated by receiver-operating characteristics (ROC), which showed high statistical significance (AUC = 0.90, p < 0.0001), thus indicating that an increased level of endometrial FUT4 mRNA may serve as a specific marker for endometriosis.

Relationship between Oxidative Stress and Endometritis: Exploiting Knowledge Gained in Mares and Cows

The etiopathogenesis of endometritis in mares and cows differs significantly; this could depend on a different sensitivity and reactivity of the uterus but also on endocrine and rearing factors and different stress sources. In both species, microorganisms and the immune system play a primary role in the generation of this pathology. Microbiological and cytological tests support clinical examination and significantly improve diagnostic accuracy. For both species, during the inflammation, immune cells invade the endometrium and release bioactive substances to contrast primary or secondary pathogen contamination. These molecules are traceable to cytokines, chemokines, and prostaglandins as well as reactive oxygen and nitrogen species (ROS and RNS), collectively known as RONS. The RONS-mediated oxidation causes morphological and functional alterations of macromolecules, such as proteins, lipids, and nucleic acids, with the consequent production of derivative compounds capable of playing harmful effects. These bioactive molecules and by-products, which have recently become increasingly popular as diagnostic biomarkers, enter the bloodstream, influencing the functionality of organs and tissues. This review has collected and compared information obtained in cows and mares related to the diagnostic potential of these biomarkers that are assessed by using different methods in samples from either blood plasma or uterine fluid.

Cancer-inducing niche: the force of chronic inflammation

The growth of cancer tissue is thought to be considered driven by a small subpopulation of cells, so-called cancer stem cells (CSCs). CSCs are located at the apex of a hierarchy in a cancer tissue with self-renewal, differentiation and tumorigenic potential that produce the progeny in the tissue. Although CSCs are generally believed to play a critical role in the growth, metastasis, and recurrence of cancers, the origin of CSCs remains to be reconsidered. We hypothesise that, chronic diseases, including obesity and diabetes, establish the cancer-inducing niche (CIN) that drives the undifferentiated/progenitor cells into CSCs, which then develop malignant tumours in vivo. In this context, a CIN could be traced to chronic inflammation that involves long-lasting tissue damage and repair after being exposed to factors such as cytokines and growth factors. This must be distinguished from the cancer microenvironment, which is responsible for cancer maintenance. The concept of a CIN is most important for cancer prevention as well as cancer therapy.

Modeling Endometrium Biology and Disease

The endometrium, lining the uterine lumen, is highly essential for human reproduction. Its exceptional remodeling plasticity, including the transformation process to welcome and nest the embryo, is not well understood. Lack of representative and reliable study models allowing the molecular and cellular mechanisms underlying endometrium development and biology to be deciphered is an important hurdle to progress in the field. Recently, powerful organoid models have been developed that not only recapitulate endometrial biology such as the menstrual cycle, but also faithfully reproduce diseases of the endometrium such as endometriosis. Moreover, single-cell profiling endeavors of the endometrium in health and disease, and of derived organoids, start to provide deeper insight into cellular complexity and expression specificities, and in resulting tissue processes. This granular portrayal will not only help in understanding endometrium biology and disease, but also in pinning down the tissue's stem cells, at present not yet conclusively defined. Here, we provide a general overview of endometrium development and biology, and the efforts of modeling both the healthy tissue, as well as its key diseased form of endometriosis. The future of modeling and deciphering this key tissue, hidden inside the womb, looks bright.

Endometriosis: A Disease with Few Direct Treatment Options

Endometriosis is a gynecological condition characterized by the growth of endometrium-like tissues inside and outside the pelvic cavity. The evolution of the disease can lead to infertility in addition to high treatment costs. Currently, available medications are only effective in treating endometriosis-related pain; however, it is not a targeted treatment. The objective of this work is to review the characteristics of the disease, the diagnostic means and treatments available, as well as to discuss new therapeutic options.

In vitro modeling of endometriosis and endometriotic microenvironment - Challenges and recent advances

Endometriosis is a chronic condition with high prevalence in reproductive age women, defined as the growth of endometrial tissue outside the uterine cavity, most commonly on the pelvic peritoneum. The ectopic endometrial lesions exist in a unique microenvironment created by the interaction of epithelial, stromal, endothelial, glandular, and immune cell components, dominated by inflammatory, angiogenic, and endocrine signals. Current research is directed at understanding the complex microenvironment of the lesions and its relationship with different endometriosis stages, phenotypes, and disease symptoms and at the development of novel diagnostic and therapeutic concepts that minimalize the undesirable side effects of current medical management. Recreating pathophysiological cellular and molecular mechanisms and identifying clinically relevant metrics to assess drug efficacy is a great challenge for the experimental disease models. This review summarizes the complete range of available in vitro experimental systems used in endometriotic studies, which reflect the multifactorial nature of the endometriotic lesion. The article discusses the simplistic in vitro models such as primary endometrial cells and endometriotic cell lines to heterogeneous 2D co-cultures, and recently more common, 3D systems based on self-organization and controlled assembly, both in microfluidic or bioprinting methodologies. Basic research models allow studying fundamental pathological mechanisms by which menstrual endometrium adheres, invades, and establishes lesions in ectopic sites. The advanced endometriosis experimental models address the critical challenges and unsolved problems and provide an approach to drug screening and medicine discovery by mimicking the complicated behaviors of the endometriotic lesion.

Perioperative Suppression of Schwann Cell Dedifferentiation Reduces the Risk of Adenomyosis Resulting from Endometrial–Myometrial Interface Disruption in Mice

We have recently demonstrated that endometrial–myometrial interface (EMI) disruption (EMID) can cause adenomyosis in mice, providing experimental evidence for the well-documented epidemiological finding that iatrogenic uterine procedures increase the risk of adenomyosis. To further elucidate its underlying mechanisms, we designed this study to test the hypothesis that Schwann cells (SCs) dedifferentiating after EMID facilitate the genesis of adenomyosis, but the suppression of SC dedifferentiation perioperatively reduces the risk. We treated mice perioperatively with either mitogen-activated protein kinase kinase (MEK)/extracellular-signal regulated protein kinase (ERK) or c-Jun N-terminal kinase (JNK) inhibitors or a vehicle 4 h before and 24 h, 48 h and 72 h after the EMID procedure. We found that EMID resulted in progressive SCs dedifferentiation, concomitant with an increased abundance of epithelial cells in the myometrium and a subsequent epithelial–mesenchymal transition (EMT). This EMID-induced change was abrogated significantly with perioperative administration of JNK or MEK/ERK inhibitors. Consistently, perioperative administration of a JNK or a MEK/ERK inhibitor reduced the incidence by nearly 33.5% and 14.3%, respectively, in conjunction with reduced myometrial infiltration of adenomyosis and alleviation of adenomyosis-associated hyperalgesia. Both treatments significantly decelerated the establishment of adenomyosis and progression of EMT, fibroblast-to-myofibroblast trans-differentiation and fibrogenesis in adenomyotic lesions. Thus, we provide the first piece of evidence strongly implicating the involvement of SCs in the pathogenesis of adenomyosis induced by EMID.

The Role of Endometrial Stem/Progenitor Cells in Recurrent Reproductive Failure

Recurrent implantation failure (RIF) and recurrent pregnancy loss (RPL), collectively referred to as recurrent reproductive failure (RRF), are both challenging conditions with many unanswered questions relating to causes and management options. Both conditions are proposed to be related to an aberrant endometrial microenvironment, with different proposed aetiologies related to a restrictive or permissive endometrium for an invading embryo. The impressive regenerative capacity of the human endometrium has been well-established and has led to the isolation and characterisation of several subtypes of endometrial stem/progenitor cells (eSPCs). eSPCs are known to be involved in the pathogenesis of endometrium-related disorders (such as endometriosis) and have been proposed to be implicated in the pathogenesis of RRF. This review appraises the current knowledge of eSPCs, and their involvement in RRF, highlighting the considerable unknown aspects in this field, and providing avenues for future research to facilitate much-needed advances in the diagnosis and management of millions of women suffering with RRF.

Endometrium as Control of Endometriosis in Experimental Research: Assessment of Sample Suitability

Endometriosis is a chronic gynecological disease that causes numerous severe symptoms in affected women. Revealing alterations of the molecular processes in ectopic endometrial tissue is the current policy for understanding the pathomechanisms and discovering potential novel therapeutic targets. Examining molecular processes of eutopic endometrium is likely to be a convenient method to compare it with the molecular alterations observed in ectopic tissues. The aim of the present study was to determine what proportion of the surgically resected eutopic endometrial samples is suitable for further experiments so that these can be comparable with endometriosis. Final hospital reports and histopathology reports of a 3-year-long period (1162 cases) were analysed. The application of a retrospective screening method promoted the categorization of these cases, and quantification of the categorized cases was accomplished. In addition, results obtained from cultured endometrium samples were also detailed. Only a small number of the harvested endometrial samples was suitable for further molecular analysis, while preoperative screening protocol could enlarge this fraction. Applying clinical and histopathological selection and exclusion criteria for tissue screening and histopathological examination of samples could ensure the comparability of healthy endometrium with endometriosis. The present study could be useful for researchers who intend to perform molecular experiments to compare endometriosis with the physiological processes of the endometrium.

The State of Health and the Quality of Life in Women Suffering from Endometriosis

Quality of life is related to good health, family relations, feeling of self-esteem, and ability to cope with difficult situations. Endometriosis is a chronic condition which affects different areas of life. The lack of satisfaction in everyday life is mainly due to constant pain. The process of adjusting to a life with illness is associated with negative emotions. The aim of the article is to review the current state of knowledge concerning the impact of social and medical factors on a population of women affected by endometriosis. Women with endometriosis have an impaired quality of life compared to the general female population. Psychological consequences of endometriosis include: depression, anxiety, powerlessness, guilt, self-directed violence, and deterioration of interpersonal relations. It may contribute to lower productivity at work and less satisfying intimate life. A multi-disciplinary, evidence-based care is needed. The disease can take away the ability to be physically active, obtain an education, work continuously, and interact with friends. Social support and cognitive-behavioral therapy are extremely important for healing.

[Avenues of reflection for endometriosis research in France]

Endometriosis is a chronic disease in which lesions resembling endometrial tissue are found outside the uterus, mainly in the pelvis or abdomen. It may affect 10% of women of childbearing age. It is the cause of a significant alteration in quality of life and a major cost to the health system. Few research teams are working on this subject, and its pathophysiology is still poorly understood. This article proposes avenues of reflection for research on endometriosis in France, notably based on the mobilization of related scientific communities (involved in cancer, development, epigenetics, and neurosciences research studies).

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.

Overexpression of miR-200b-3p in Menstrual Blood-Derived Mesenchymal Stem Cells from Endometriosis Women

The key relationship between Sampson's theory and the presence of mesenchymal stem cells in the menstrual flow (MenSCs), as well as the changes in post-transcriptional regulatory processes as actors in the etiopathogenesis of endometriosis, are poorly understood. No study to date has investigated the imbalance of miRNAs in MenSCs related to the disease. Thus, through literature and in silico analyses, we selected four predicted miRNAs as regulators of EGR1, SNAI1, NR4A1, NR4A2, ID1, LAMC3, and FOSB involved in pathways of apoptosis, angiogenesis, response to steroid hormones, migration, differentiation, and cell proliferation. These genes are frequently overexpressed in the endometriosis condition in our group studies. They were the trigger for the miRNAs search. Therefore, a case-control study was conducted with MenSCs of women with and without endometriosis (ten samples per group). Crossing information obtained from the STRING, PubMed, miRPathDB, miRWalk, and DIANA TOOLS databases, we chose to explore the expression of miR-21-5p, miR-100-5p, miR-143-3p, and miR-200b-3p by RT-qPCR. We found an upregulation of the miR-200b-3p in endometriosis MenSCs (P = 0.0207), with a 7.93-fold change (ratio of geometric means) compared to control. Overexpression of miR-200b has been associated with increased cell proliferation, stemness, and accentuated mesenchymal-epithelial transition process in eutopic endometrium of endometriosis. We believe that dysregulated miR-200b-3p may establish primary changes in the MenSCs, thus favoring tissue implantation at the ectopic site.

Endometrial Stem/Progenitor Cells–Their Role in Endometrial Repair and Regeneration

The human endometrium is a remarkable tissue, undergoing ~450 cycles of proliferation, differentiation, shedding (menstruation), repair, and regeneration over a woman's reproductive lifespan. Post-menstrual repair is an extremely rapid and scar-free process, with re-epithelialization of the luminal epithelium completed within 48 h of initiation of shedding. Following menstruation, the functionalis grows from the residual basalis layer during the proliferative phase under the influence of rising circulating estrogen levels. The regenerative capacity of the endometrium is attributed to stem/progenitor cells which reside in both the epithelial and stromal cell compartments of the basalis layer. Finding a definitive marker for endometrial epithelial progenitors (eEPCs) has proven difficult. A number of different markers have been suggested as putative progenitor markers including, N-cadherin, SSEA-1, AXIN2, SOX-9 and ALDH1A1, some of which show functional stem cell activity in in vitro assays. Each marker has a unique location(s) in the glandular epithelium, which has led to the suggestion that a differentiation hierarchy exists, from the base of epithelial glands in the basalis to the luminal epithelium lining the functionalis, where epithelial cells express different combinations of markers as they differentiate and move up the gland into the functionalis away from the basalis niche. Perivascular endometrial mesenchymal stem cells (eMSCs) can be identified by co-expression of PDGFRβ and CD146 or by a single marker, SUSD2. This review will detail the known endometrial stem/progenitor markers; their identity, location and known interactions and hierarchy across the menstrual cycle, in particular post-menstrual repair and estrogen-driven regeneration, as well as their possible contributions to menstruation-related disorders such as endometriosis and regeneration-related disorder Asherman's syndrome. We will also highlight new techniques that allow for a greater understanding of stem/progenitor cells' role in repair and regeneration, including 3D organoids, 3D slice cultures and gene sequencing at the single cell level. Since mouse models are commonly used to study menstruation, repair and regeneration we will also detail the mouse stem/progenitor markers that have been investigated in vivo.

Endometriosis, an Ongoing Pain—Step-by-Step Treatment

Endometriosis is a disease that is becoming more and more challenging for the medical community. The current therapeutic concepts (surgical therapy and/or hormonal therapies) often do not lead to sufficient pain control, and late diagnosis and high recurrence rates mean that women affected by the disease can suffer for decades before receiving proper treatment. Although the introduction of certified endometriosis centers has created contact points for surgical therapies performed by endometriosis experts, these centers are not sufficient to offer the affected patients the all-encompassing long-term support they need. In recent years, new findings regarding the pathogenesis and correlations of the pain phenomena caused by endometriosis have shown that conventional therapy strategies are not adequate and individual long-term concepts must be developed. Not only can endometriosis cause nociceptive pain, but it can also lead to a nociplastic reaction with central sensitization. Hence, aside from the classic cyclic complaints, patients increasingly suffer from atypical pain. Due to the high number of affected patients who are treated inadequately, it is necessary for gynecologists in private practices to become familiar with multimodal treatment concepts since they are the central point of contact of their patients. The following article will provide an overview of treatment strategies for chronic symptomatic endometriosis.

Age-dependent phenotypes of ovarian endometriomas

Purpose

To analyze the characteristics of the ovarian endometrioma (OE) across the life span of a woman. In the past, the OE has traditionally been viewed as a single, monolithic disease. Today, there are emerging data indicating that OE phenotypes differ according to the age of the woman.

Method

A narrative review of original articles on OE indexed by PubMed.

Results

When appearing in infancy and early adolescence, OE may be the consequence of endometrial cells retrogradely shed with neonatal uterine bleeding. The post-menarcheal variant, manifesting itself during full adolescence, is singularly frequent in the presence of vaginal or uterine outflow obstructive anomalies. The typical and most frequent adult phenotype is characterized by increasing fibrosis and a tendency to progress; its mere presence exerts a detrimental effect on the surrounding healthy ovarian tissue. In postmenopause, an old lesion may be reactivated in the presence of exogenous or endogenous estrogens, or even be produced ex novo; rarely, it can spread to a variety of organs and structures and even degenerate causing malignancies.

Conclusions

Given the existence of these variants, it is important to agree on management guidelines that take into consideration these different phenotypes.

Stem Cell Therapies for Human Infertility: Advantages and Challenges

Physical and mental health and hormonal imbalance are associated with the problems related to infertility and reproductive disorders. The rate of infertility has increased globally over the years, due to various reasons. Given the psychosocial implications of infertility and its effects on the life of the affected people, there has been an increased focus on its treatment over the last several years. Assisted reproductive technology can only solve about 50% of the cases. Moreover, it contains significant risks and does not solve the fundamental problem of infertility. As pluripotent stem cells have the potential to differentiate into almost any type of cell, they have been widely regarded as a promising option in the development of stem cell-based fertility treatments, which could even correct genetic diseases in offspring. These advancements in reproductive biotechnology present both challenges and possibilities for solving infertility problems caused by various unexplainable factors. This review briefly presents the different types of infertility disorders and the potential applications of stem cells in the treatment of these reproductive diseases.

Deep Infiltrating Endometriosis and Adenomyosis: Implications on Pregnancy and Outcome

Endometriosis (EM), especially deep infiltrating endometriosis (DIE) and adenomyosis (AM), are known to cause pain and sterility in young women. More recently, they have also been described as risk factors for obstetric complications. While the pathophysiology is not yet completely understood, they seem to share a common origin: archimetrosis. Methods: A systematic literature review was conducted to summarize the existing evidence on DIE and AM as risk factors for obstetric complications. Results: Preterm birth, caesarean section delivery (CS) and placental abnormalities are associated with the diagnosis of DIE and AM. Women with AM seem to experience more often hypertensive pregnancy disorders, premature rupture of membranes and their children are born with lower birth weights than in the control groups. However, many of the studies tried to evaluate AM, EM and DIE as separate risk factors. Moreover, often they did not adjust for important confounders such as multiple pregnancies, parity, mode of conception and maternal age. Therefore, prospective studies with larger numbers of cases and appropriate adjustment for confounders are needed to explore the pathophysiology and to prove causality.

Decidualization Potency and Epigenetic Changes in Human Endometrial Origin Stem Cells During Propagation

Human endometrium derived mesenchymal stem cells (hEndSCs) offer a great promise for regenerative medicine and reproductive system disorders treatment methods based on cell therapy due to their broad differentiation potential and highly efficient proliferation. In our study, we investigated the characteristics of hEndSCs that were isolated from two sources: endometrium and menstrual blood, which both contain endometrial origin stem cells. Changes in gene and protein expression levels during long-term cultivation and decidualization potential were examined in endometrial stem cells (EndSCs) and menstrual blood stem cells (MenSCs). The decidualization process was induced on early and late passages of hEndSCs using dibutyryl cyclic-AMP (db-cAMP) and medroxyprogesterone acetate (MPA) agents. We demonstrated that after long-term cultivation of hEndSCs the expression of typical mesenchymal stromal cell surface markers such as CD44, CD73, CD90, CD105 and perivascular marker CD146 remains at a similar level throughout long-term cultivation. Additionally, hematopoietic and endothelial markers CD34, CD45 were also tested, they were negative in all cases. Analyzed stem cells gene markers, such as OCT4, SOX2, NANOG, KLF4, showed similar expression in all passages of hEndSCs. RT-qPCR results demonstrated that the expression of cell cycle control associated genes - CDK2, CCNA2, CCNE2, p21, p53 and Rb, among all groups was very similar. Expression of genes associated with senescence (ATM, JUND, TOP2A, MYC) was maintained at a similar level throughout passaging. In addition, Western blot analysis was used to assess changes in proteins’ levels associated to epigenetics (EZH2, SUZ12, H3K27me3) and cell cycle control (cyclinE1, p53) during long-term cultivation. The levels of proteins associated with epigenetic changes were fluctuated slightly depending on the patient. Also, we demonstrated that in all induced hEndSCs the expression of decidualization markers Prolactin (PRL), IGFBP1 and WNT4 was upregulated. In conclusion, we demonstrated successful decidualization of stem cells derived from two reproductive system resources: endometrium and menstrual blood by using db-cAMP and MPA regardless of the length of the stem cell passaging. According these findings, we suppose that endometrium derived stem cells and menstrual blood derived stem cells could have a potency not only for endometrium tissue regeneration, but could also become a successful therapy for reproductive system disorders, including infertility or recurrent pregnancy loss.

Mice Uterine Stem Cells are Affected by Neonatal Endocrine Disruption & Initiate Uteropathies in Adult Life Independent of Circulatory Ovarian Hormones

It is generally believed that ovarian hormones regulate uterine functions and their altered levels result in various uteropathies like non-receptive uterus, endometrial hyperplasia, adenomyosis, endometriosis, leiomyomas and cancer. Uterus harbors two populations of stem cells including pluripotent, very small embryonic-like stem cells (VSELs) and tissue-specific progenitors (endometrial stem cells, EnSCs). Unlike endometrial mesenchymal stem/ stromal cells, VSELs/EnSCs express ERα, ERβ and PR which makes them directly vulnerable to perinatal endocrine insults. Present study was undertaken to evaluate whether uteropathies occur due to altered hormones and/or intrinsic changes in stem/progenitor cells. Mice pups, exposed to estradiol (20 µg/pup/day) on postnatal days 3-7 or vehicle, were subjected to bilateral ovariectomy on day 30 and later exposed sequentially to estradiol and progesterone resulting in receptive uterus in control mice. Despite similar hormonal exposure, endocrine disruption resulted in non-receptive uterus with noticeable endometrial and myometrial hyperplasia and up-regulation of stem cell markers (Oct-4A, Oct-4, Sox2, Nanog). Glands were poorly formed and 'defective' epithelial progenitors were found disseminated into myometrium and blood vessels revealing how adenomyosis and endometriosis possibly initiate. Progesterone resistance and estradiol dominance due to downregulation of Erα & Pr and upregulation of Erβ transcripts was observed in both intact uterus and stem cells enriched from uterus. Transcripts specific for DNA mismatch repair axis (Pcna, NP95 and Dnmt1), repair enzymes (Brca-1, Rad51 and Mlh1) were dysregulated whereas Ki67 was ten-folds increased suggestive of genomic instability. Study reveals role of stem cells in initiating uteropathies during adult life independent of circulatory ovarian hormones. Endocrine disruption affects tissue resident stem/progenitor cells (VSELs/EnSCs) in both endometrium and myometrium, result in epithelial cells hyperplasia, non-receptive endometrium, adenomyosis and defective stem cells and epithelial progenitors were detected in the perimetrium from where they can mobilize to ectopic sites to initiate endometriosis. Study shows stem cell basis for various uteropathies. VSEL: Very small embryonic like stem cell; EnSC: Endometrial stem cell; E + P: Estradiol + Progesterone; E: Endometrium; P: Perimetrium; M: Myometrium; ACD: Asymmetrical cell division; SCD: Symmetrical cell division; CE: Clonal expansion; G: Gland; S: Stromal cell; US: Undifferentiated stromal cell; LE: Luminal epithelium; GE: Glandular epithelium; EP: Epithelial progenitors; SMC: Spindle-shaped myometrial cell; OMC: Oval-shaped myometrial cell.

The role of endometrial stem cells in the pathogenesis of endometriosis and their application to its early diagnosis†

Pelvic pain, infertility, and a high postoperative recurrence rate are associated with endometriosis and adversely affect the physical and mental health of patients. Moreover, these factors place a heavy burden on families and society. The identification of endometrial stem cells (EnSCs) in the eutopic endometrium, menstrual blood, and ectopic lesions of women with endometriosis not only provides new research objects in the context of endometriosis but also promotes and improves our understanding of its pathogenesis. Furthermore, based on previous studies, we reasonably suppose that dysfunctions of eutopic EnSCs play a critical role in the onset of endometriosis and directly cause abnormalities in the endometrium; subsequently, retrograde menstruation facilitates the delivery of abnormal endometrial tissues to the ovaries and pelvic cavity, where they ectopically implant, grow, and form ectopic lesions. Additionally, as a chronically progressive disease, there is a delay (3-11 years) from the first onset of symptoms to the diagnosis of endometriosis. Therefore, the development of a method for early diagnosis with high sensitivity and specificity is essential for endometriosis patients and has the potential to enable early treatment, prevent endometriosis progression, and relieve pain in patients. Thus, focusing on EnSCs will contribute to clarifying the potential pathogenesis of endometriosis and provide support for the application of EnSCs as therapeutic and early diagnostic targets in endometriosis treatment.

SUMMARY SENTENCE

Focusing on endometrial stem cells (EnSCs) will contribute to clarifying the potential pathogenesis of endometriosis and provide support for the application of EnSCs as therapeutic and early diagnostic targets in endometriosis treatment.

Molecular Basis of Endometriosis and Endometrial Cancer: Current Knowledge and Future Perspectives

The human endometrium is a unique tissue undergoing important changes through the menstrual cycle. Under the exposure of different risk factors in a woman's lifetime, normal endometrial tissue can give rise to multiple pathologic conditions, including endometriosis and endometrial cancer. Etiology and pathophysiologic changes behind such conditions remain largely unclear. This review summarizes the current knowledge of the pathophysiology of endometriosis and its potential role in the development of endometrial cancer from a molecular perspective. A better understanding of the molecular basis of endometriosis and its role in the development of endometrial pathology will improve the approach to clinical management.

Menstrual fluid endometrial stem/progenitor cell and supernatant protein content: cyclical variation and indicative range

STUDY QUESTION

Does natural variation exist in the endometrial stem/progenitor cell and protein composition of menstrual fluid across menstrual cycles in women?

SUMMARY ANSWER

Limited variation exists in the percentage of some endometrial stem/progenitor cell types and abundance of selected proteins in menstrual fluid within and between a cohort of women.

WHAT IS KNOWN ALREADY

Menstrual fluid is a readily available biofluid that can represent the endometrial environment, containing endometrial stem/progenitor cells and protein factors. It is unknown whether there is natural variation in the cellular and protein content across menstrual cycles of individual women, which has significant implications for the use of menstrual fluid in research and clinical applications.

STUDY DESIGN, SIZE, DURATION

Menstrual fluid was collected from 11 non-pregnant females with regular menstrual cycles. Participants had not used hormonal medications in the previous 3 months. Participants collected menstrual fluid samples from up to five cycles using a silicone menstrual cup worn on Day 2 of menstrual bleeding.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Menstrual fluid samples were centrifuged to separate soluble proteins and cells. Cells were depleted of red blood cells and CD45+ leucocytes. Menstrual fluid-derived endometrial stem/progenitor cells were characterized using multicolour flow cytometry including markers for endometrial stem/progenitor cells N-cadherin (NCAD) and stage-specific embryonic antigen-1 (SSEA-1) (for endometrial epithelial progenitor cells; eEPC), and sushi domain containing-2 (SUSD2) (for endometrial mesenchymal stem cells; eMSC). The clonogenicity of menstrual fluid-derived endometrial cells was assessed using colony forming unit assays. Menstrual fluid supernatant was analyzed using a custom magnetic Luminex assay.

MAIN RESULTS AND THE ROLE OF CHANCE

Endometrial stem/progenitor cells are shed in menstrual fluid and demonstrate clonogenic properties. The intraparticipant agreement for SUSD2+ menstrual fluid-derived eMSC (MF-eMSC), SSEA-1+ and NCAD+SSEA-1+ MF-eEPC, and stromal clonogenicity were moderate-good (intraclass correlation; ICC: 0.75, 0.56, 0.54 and 0.52, respectively), indicating limited variability across menstrual cycles. Endometrial inflammatory and repair proteins were detectable in menstrual fluid supernatant, with five of eight (63%) factors demonstrating moderate intraparticipant agreement (secretory leukocyte protein inhibitor (SLPI), lipocalin-2 (NGAL), lactoferrin, follistatin-like 1 (FSTL1), human epididymis protein-4 (HE4); ICC ranges: 0.57-0.69). Interparticipant variation was limited for healthy participants, with the exception of key outliers of which some had self-reported menstrual pathologies.

LARGE SCALE DATA

N/A. There are no OMICS or other data sets relevant to this study.

LIMITATIONS, REASONS FOR CAUTION

The main limitations to this research relate to the difficulty of obtaining menstrual fluid samples across multiple menstrual cycles in a consistent manner. Several participants could only donate across <3 cycles and the duration of wearing the menstrual cup varied between 4 and 6 h within and between women. Due to the limited sample size used in this study, wider studies involving multiple consecutive menstrual cycles and a larger cohort of women will be required to fully determine the normal range of endometrial stem/progenitor cell and supernatant protein content of menstrual fluid. Possibility for selection bias and true representation of the population of women should also be considered.

WIDER IMPLICATIONS OF THE FINDINGS

Menstrual fluid is a reliable source of endometrial stem/progenitor cells and related endometrial proteins with diagnostic potential. The present study indicates that a single menstrual sample may be sufficient in characterizing a variety of cellular and protein parameters across women's menstrual cycles. The results also demonstrate the potential of menstrual fluid for identifying endometrial and menstrual abnormalities in both research and clinical settings as a non-invasive method for assessing endometrial health.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by grants from the Australian National Health and Medical Research Council to C.E.G. (Senior Research Fellowship 1024298 and Investigator Fellowship 1173882) and to J.E. (project grant 1047756), the Monash IVF Research Foundation to C.E.G. and the Victorian Government's Operational Infrastructure Support Program. K.A.W., M.L.D.-T., S.G.S. and J.E. declare no conflicts of interest. C.E.G. reports grants from NHMRC, during the conduct of the study; grants from EndoFound USA, grants from Ferring Research Innovation, grants from United States Department of Defence, grants from Clue-Utopia Research Foundation, outside the submitted work. CEF reports grants from EndoFound USA, grants from Clue-Utopia Research Foundation, outside the submitted work.

LncRNA small nucleolar RNA host gene 16 (SNHG16) silencing protects lipopolysaccharide (LPS)-induced cell injury in human lung fibroblasts WI-38 through acting as miR-141-3p sponge

Long noncoding RNA (LncRNA) small nucleolar RNA host gene 16 (SNHG16) is correlated with cell injuries, including pneumonia. However, its role and mechanism remain vague in pneumonia. The interplay among genes was confirmed by dual-luciferase reporter assay, RNA immunoprecipitation, and RNA pull-down assay. SNHG16 and sushi domain containing 2 (SUSD2) were upregulated, and miRNA (miR)-141-3p was downregulated in the serum of acute pneumonia patients and lipopolysaccharide (LPS)-challenged human lung fibroblasts WI-38. LPS induced apoptosis, autophagy, and inflammatory response in WI-38 cells, which was significantly attenuated by SNHG16 knockdown and/or miR-141-3p overexpression. Notably, both SNHG16 and SUSD2 were identified as target genes of miR-141-3p. Besides, the suppressive role of SNHG16 knockdown in LPS-induced in WI-38 cells was partially abolished by miR-141-3p silencing, and the similar inhibition of miR-141-3p overexpression was further blocked by SUSD2 restoration. In conclusion, knockdown of SNHG16 could alleviate LPS-induced apoptosis, autophagy, and inflammation in WI-38 cells partially though the SNHG16/miR-141-3p/SUSD2 pathway.

Bioluminescent imaging in induced mouse models of endometriosis reveals differences in four model variations

Our understanding of the aetiology and pathophysiology of endometriosis remains limited. Disease modelling in the field is problematic as many versions of induced mouse models of endometriosis exist. We integrated bioluminescent imaging of 'lesions' generated using luciferase-expressing donor mice. We compared longitudinal bioluminescence and histology of lesions, sensory behaviour of mice with induced endometriosis and the impact of the gonadotropin-releasing hormone antagonist Cetrorelix on lesion regression and sensory behaviour. Four models of endometriosis were tested. We found that the nature of the donor uterine material was a key determinant of how chronic the lesions were, as well as their cellular composition. The severity of pain-like behaviour also varied across models. Although Cetrorelix significantly reduced lesion bioluminescence in all models, it had varying impacts on pain-like behaviour. Collectively, our results demonstrate key differences in the progression of the 'disease' across different mouse models of endometriosis. We propose that validation and testing in multiple models, each of which may be representative of the different subtypes/heterogeneity observed in women, should become a standard approach to discovery science in the field of endometriosis.

Relationship Between Dairy Products Intake and Risk of Endometriosis: A Systematic Review and Dose-Response Meta-Analysis

Objective: Diet lifestyle can influence the risk of endometriosis. Therefore, we conducted a systematic meta-analysis to investigate the association between dairy products and the risk of endometriosis. Besides, we performed a dose-response meta-analysis to evaluate the amount of dairy intake affecting the risk of endometriosis.

Methods: Relevant studies were searched from Pubmed, Embase databases, Cochrane Library, and Web of Science from the inception to November 6th, 2020. Also, the dose-response meta-analysis was conducted. All the pooled results were performed by risk ratios (RRs).

Results: Finally, seven high-quality studies were included in the present meta-analysis. Total dairy intake was inversely associated with the risk of endometriosis, and the risk of endometriosis tended to decrease with a decrease in the risk of endometriosis when dairy products intake was over 21 servings/week (RR 0.87, 95% CI 0.76–1.00; p_{non−linearity} = 0.04). Similarly, people who consumed more than 18 servings of high-fat dairy products per week had a reduced risk of endometriosis (RR 0.86, 95% CI 0.76–0.96). When stratified-analyses were conducted based on specific dairy product categories, it indicated that people with high cheese intake might have a reduced risk of endometriosis (RR 0.86, 95% CI 0.74–1.00). Other specific dairy products such as whole milk (RR 0.90, 95% CI 0.72–1.12), reduced-fat/skim milk (RR 0.83, 95% CI 0.50–1.73), ice cream (RR 0.83, 95% CI 0.50–1.73), and yogurt (RR 0.83, 95% CI 0.62–1.11) have not shown significant evidence of an association with the risk of endometriosis. However, there is a higher risk of endometriosis in the females with high butter intake compared to females with low butter intake (1.27, 95% CI 1.03–1.55).

Conclusions: Overall, dairy products intake was associated with a reduction in endometriosis, with significant effects when the average daily intake ≥3 servings. When analyzed according to the specific type of dairy product, it was shown that females with higher high-fat dairy and cheese intake might have a reduced risk of endometriosis. However, high butter intake might be associated to the increased risk of endometriosis. More future studies are needed to validate and add to this finding.

Pathogenesis of Endometriosis: The Origin of Pain and Subfertility

Endometriosis (EM) and adenomyosis (AM) are common conditions with pain and infertility as the principal symptoms. The pathophysiology of pain in EM and AM comprises sensory and somatoform pain mechanisms. Over time, these may aggravate and lead to individual complex disease patterns if not diagnosed and treated. Despite the known facts, several years often pass between the onset of symptoms and diagnosis. Chronic pain disorders with changes on a neuronal level frequently arise and are linked to depressive disorders, with the process becoming a vicious cycle. Additionally, women with EM and AM suffer from sub- and infertility. Low fecundity rates are caused by anatomical changes in combination with behavioral changes in the sexual activity of women with chronic pain as well as local proinflammatory factors that not only decrease implantation rates but also promote early abortions.

The ellagic acid metabolites urolithin A and B differentially affect growth, adhesion, motility, and invasion of endometriotic cells in vitro

STUDY QUESTION

What are the effects of plant-derived antioxidant compounds urolithin A (UA) and B (UB) on the growth and pathogenetic properties of an in vitro endometriosis model?

SUMMARY ANSWER

Both urolithins showed inhibitory effects on cell behavior related to the development of endometriosis by differentially affecting growth, adhesion, motility, and invasion of endometriotic cells in vitro.

WHAT IS KNOWN ALREADY

Endometriosis is one of the most common benign gynecological diseases in women of reproductive age and is defined by the presence of endometrial tissue outside the uterine cavity. As current pharmacological therapies are associated with side effects interfering with fertility, we aimed at finding alternative therapeutics using natural compounds that can be administered for prolonged periods with a favorable side effects profile.

STUDY DESIGN, SIZE, DURATION

In vitro cultures of primary endometriotic stromal cells from 6 patients subjected to laparoscopy for benign pathologies with histologically confirmed endometriosis; and immortalized endometrial stromal (St-T1b) and endometriotic epithelial cells (12Z) were utilized to assess the effects of UA and UB on endometriotic cell properties. Results were validated in three-dimensional (3D) in vitro co-culture spheroids of 12Z and primary endometriotic stroma cells of one patient, and organoids from 3 independent donors with endometriosis.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The effects on cell growth were measured by non-radioactive colorimetric assay to measure cellular metabolic activity as an indicator of cell viability (MTT assay) and flow cytometric cell cycle assay on primary cultures, St-T1b, and 12Z. Apoptosis analyses, the impact on in vitro adhesion, migration, and invasion were evaluated in the cell lines. Moreover, Real-Time Quantitative Reverse Transcription polymerase chain reaction (RT-qPCR) assays were performed on primary cultures, St- T1b and 12Z to evaluate a plausible mechanistic contribution by factors related to proteolysis (matrix metalloproteinase 2, 3 and 9 -MMP2, MMP3, MMP9-, and tissue inhibitor of metalloproteinases -TIMP-1-), cytoskeletal regulators (Ras-related C3 botulinum toxin substrate 1 -RAC1-, Rho-associated coiled-coil containing protein kinase 2 -ROCK2-), and cell adhesion molecules (Syndecan 1 -SDC1-, Integrin alpha V-ITGAV-). Finally, the urolithins effects were evaluated on spheroids and organoids by formation, viability, and drug screen assays.

MAIN RESULTS AND THE ROLE OF CHANCE

40 µM UA and 20 µM UB produced a significant decrease in cell proliferation in the primary endometriotic cell cultures (P < 0.001 and P < 0.01, respectively) and in the St-T1b cell line (P < 0.001 and P < 0.05, respectively). In St-T1b, UA exhibited a mean half-maximum inhibitory concentration (IC50) of 39.88 µM, while UB exhibited a mean IC50 of 79.92 µM. Both 40 µM UA and 20 µM UB produced an increase in cells in the S phase of the cell cycle (P < 0.01 and P < 0.05, respectively). The same concentration of UA also increased the percentage of apoptotic ST-t1b cells (P < 0.05), while both urolithins decreased cell migration after 24 h (P < 0.001 both). Only the addition of 5 µM UB decreased the number of St-T1b adherent cells. TIMP-1 expression was upregulated in response to treating the cells with 40 µM UA (P < 0.05). Regarding the 12Z endometriotic cell line, only 40 µM UA decreased proliferation (P < 0.01); while both 40 µM UA and 20 µM UB produced an increase in cells in the G2/M phase (P < 0.05 and P < 0.01, respectively). In this cell line, UA exhibited a mean IC50 of 40.46 µM, while UB exhibited a mean IC50 of 54.79 µM. UB decreased cell migration (P < 0.05), and decreased the number of adherent cells (P < 0.05). Both 40 µM UA and 20 µM UB significantly decreased the cellular invasion of these cells; and several genes were altered when treating the cells with 40 µM UA and 10 µM UB. The expression of MMP2 was downregulated by UA (P < 0.001), and expression of MMP3 (UA P < 0.001 and UB P < 0.05) and MMP9 (P < 0.05, both) were downregulated by both urolithins. Moreover, UA significantly downregulated ROCK2 (P < 0.05), whereas UB treatment was associated with RAC1 downregulation (P < 0.05). Finally, the matrix adhesion receptors and signaling (co)receptors SDC1 and ITGAV were downregulated upon treatment with either UA or UB (P < 0.01 and P < 0.05, respectively in both cases). Regarding the effects of urolithins on 3D models, we have seen that they significantly decrease the viability of endometriosis spheroids (80 µM UA and UB: P < 0.05 both) as well as affecting their area (40 µM UA: P < 0.05, and 80 µM UA: P < 0.01) and integrity (40 µM UA and UB: P < 0.05, 80 µM UA and UB: P < 0.01). On the other hand, UA and UB significantly inhibited organoid development/outgrowth (40 and 80 µM UA: P < 0.0001 both; 40 µM UB: P < ns-0.05-0.001, and 80 µM UB: P < 0.01-0.001-0.001), and all organoid lines show urolithins sensitivity resulting in decreasing viability (UA exhibited a mean IC50 of 33.93 µM, while UB exhibited a mean IC50 of 52.60 µM).

LARGE-SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

This study was performed on in vitro endometriosis models.

WIDER IMPLICATIONS OF THE FINDINGS

These in vitro results provide new insights into the pathogenetic pathways affected by these compounds and mark their use as a potential new therapeutic strategy for the treatment of endometriosis.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded EU MSCA-RISE-2015 project MOMENDO (691058). The authors have no conflicts of interest to declare.

In Vitro Implantation Model Using Human Endometrial SUSD2+ Mesenchymal Stem Cells and Myometrial Smooth Muscle Cells

Objective

This study evaluated a novel in vitro implantation model using human endometrial mesenchymal stem cells (EMSCs), SUSD2⁺, and myometrial smooth muscle cells (SMCs) that were co-cultured with mouse blastocysts as the surrogate embryo.

Materials and Methods

In this experimental study, SUSD2⁺ MSCs were isolated from human endometrial cell suspensions (ECS) at the fourth passage by magnetic-activated cell sorting. The ECS and SUSD2⁺ cells were separately co-cultured with human myometrial muscle cells for five days. After collection of mouse blastocysts, the embryos were placed on top of the co-cultured cells for 48 hours. The interaction between the embryo and the cultured cells was assessed morphologically at the histological and ultrastructural levels, and by expression profiles of genes related to implantation.

Results

Photomicrographs showed that trophoblastic cells grew around the embryonic cells and attached to theECS and SUSD2⁺ cells. Ultrastructural observations revealed pinopode and microvilli-like structures on the surfaces of both the ECS and SUSD2⁺ cells. Morphologically, the embryos developed to the egg-cylinder stage in both groups. Gene expression analysis showed no significant differences between the two groups in the presence of an embryo, but an increased expression of αV was detected in SUSD2⁺ cells compared to ECS cells in the absence of an embryo.

Conclusion

This study showed that SUSD2⁺ cells co-cultured with SMCs could interact with mouse embryos. The co-cultured cells could potentially be used as an implantation model.

Endometrial stem/progenitor cells in menstrual blood and peritoneal fluid of women with and without endometriosis

RESEARCH QUESTION

Are endometrial stem/progenitor cells shed into uterine menstrual blood (UMB) and the peritoneal cavity in women with and without endometriosis during menstruation?

DESIGN

Women with (n = 32) and without endometriosis (n = 29) at laparoscopy (total 61), carried out during the menstrual (n = 41) and non-menstrual phase (n = 20) were recruited. The UMB, peritoneal fluid and peripheral blood were analysed by clonogenicity assay and flow cytometry to quantify the concentrations of endometrial clonogenic cells, SUSD2⁺ mesenchymal stem cells (eMSC) and N-cadherin⁺ epithelial progenitor cells (eEPC).

RESULTS

Clonogenic endometrial cells, eMSC and eEPC were found in most UMB samples at similar concentrations in women with and without endometriosis. In contrast, 62.5% of women with endometriosis and 75.0% without (controls) had clonogenic cells in peritoneal fluid samples during menses. The eMSC were present in the peritoneal fluid of 76.9% of women with endometriosis and 44.4% without, and eEPC were found in the peritoneal fluid of 60.0% of women with and 25.0% without endometriosis during menses. Median clonogenic, eMSC and eEPC concentrations in peritoneal fluid were not significantly different between groups. More clonogenic cells persisted beyond the menstrual phase in the peritoneal fluid of women with endometriosis (menstrual 119/ml [0-1360/ml] versus non-menstrual 8.5/ml [0-387/ml]; P = 0.277) compared with controls (menstrual 76.5/ml [1-1378/ml] versus non-menstrual 0/ml [0-14/ml]; P = 0.0362). No clonogenic endometrial cells were found in peripheral blood.

CONCLUSIONS

Clonogenic endometrial cells, SUSD2⁺ eMSC and N-cadherin⁺ eEPC are present in UMB and the peritoneal fluid of women with and without endometriosis. Further study of the function of these cells may shed light on the cellular origins of endometriosis.