Endometriosis in a 22-Year-Old with Premature Ovarian Insufficiency Secondary to Pre-Pubertal Bone Marrow Transplant: a Case Report

Endometriosis is often diagnosed in reproductive aged women with spontaneous ovarian activity. Here we described a case of endometriosis diagnosed in a patient with premature ovarian insufficiency (POI) due to prepubertal bone marrow transplant (BMT). The patient is a 22-year-old nulligravid female who presented with chronic pelvic pain. She had an inherited bone marrow failure syndrome (Diamond-Blackfan anemia), which required gonadotoxic chemotherapy for BMT at a young age prior to puberty. At age 13, she received hormone therapy with transdermal estrogen with subsequent addition of cyclic progestin and was later transitioned to combined oral contraceptive pills (COC). Endometriosis was suspected due to progressive dysmenorrhea and multiple cyclic systemic symptoms. She underwent a trial of elagolix, but could not tolerate it due to worsened arthralgia. Norethindrone acetate (NET-A) was then started, and she underwent diagnostic laparoscopy. Laparoscopy revealed scattered superficial endometriotic lesions in the pelvis. Histological studies showed florid endometriosis. Patient continues on NET-A 10mg and oral estradiol 0.5mg daily since the surgery and has experienced sustained improvement in her symptoms. Endometriosis should be considered as a possible cause for progressive dysmenorrhea or pelvic pain, even in the setting of POI. The balance between HT for overall health benefits in young women with POI and the risk of endometriosis exacerbation is delicate, but achievable.

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.

Long-term effects of surgically corrected menstrual outflow obstruction: A case-control study

OBJECTIVE

To enhance evidence-based knowledge on long-term sequalae in patients with surgically corrected obstructing Müllerian anomalies.

METHODS

This long-term case-control study included patients with menstrual outflow obstruction due to congenital anomalies of the uterus or vagina, who were at least 18 years old, and for whom 2 years had elapsed since the first surgery at the start of this study. The control group consisted of women without current gynecological problems. Patients underwent a surgical correction at the Radboud University Medical Center Nijmegen between 1980 and 2013. Of 78 patients approached, 38 (49%) were included in this study. The control group consisted of 54 females. The main outcome measures were pain and health state. The following questionnaires were used: Visual Analogue Scale pain scores, European Quality of Life-5 Dimensions questionnaire (EQ-5D-3L) and the adapted Endometriosis Health Profile questionnaire (EHP-30).

RESULTS

Patients had higher actual and maximum abdominal pain scores compared with controls (11 vs 0 [P = 0.007] and 48 vs 21 [P = 0.035], respectively). Based on the EQ-5D-3L scores, patients had more pain and discomfort (P = 0.005), more mood problems (P = 0.023), and a poorer subjective health state (P = 0.002) and self-rated health state (P = 0.031). Based on the EHP-30, patients had a significant poorer self-rated health state on four out of five subscales.

CONCLUSION

In this study, following surgically corrected menstrual obstruction, patients had statistically significant higher abdominal pain scores and a poorer self-rated health state compared with controls.

Deep Infiltrating Endometriosis in Adolescence: Early Diagnosis and Possible Prevention of Disease Progression

Endometriosis has a prevalence of 10% worldwide in premenopausal women. Probably, endometriosis begins early in the life of young girls, and it is commonly diagnosed later in life. The prevalence of deep infiltrating endometriosis (DIE) in adolescence is currently unknown due to diagnostic limits and underestimation of clinical symptoms. Dysmenorrhea is a common symptom in adolescents affected by DIE, often accompanied by dyspareunia and chronic acyclic pelvic pain. Ultrasonography-either performed transabdominal, transvaginal or transrectal-should be considered the first-line imaging technique despite the potential for missed diagnosis due to early-stage disease. Magnetic resonance imaging should be preferred in the case of virgo patients or when ultrasonographic exam is not accepted. Diagnostic laparoscopy is deemed acceptable in the case of suspected DIE not responding to conventional hormonal therapy. An early medical and/or surgical treatment may reduce disease progression with an immediate improvement in quality of life and fertility, but at the same time, painful symptoms may persist or even recur due to the surgery itself. The aim of this narrative review is to report the prevalence of DIE in adolescents, describe the pathogenetic theories and discuss the management in adolescent women, including the challenging road to diagnosis and the treatment alternatives.

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.

How to Manage Endometriosis in Adolescence: The Endometriosis Treatment Italian Club Approach

The evaluation of endometriosis in an adolescent girl is a challenging topic. The initial stage of the disease and the limited diagnostic instrument appropriate for the youth age and for its typical features can reduce the ability of the gynecologist. At the same time, missing a prompt diagnosis can delay the beginning of specific and punctual management of endometriosis, which could avoid a postponed diagnosis from 6 to 12 years, typical of adolescent girls complaining of dysmenorrhea. This article aimed to answer all the potential questions around the diagnosis and management of endometriosis in adolescents starting from a clinical case looking at the possible solution that is easily reproducible in the clinical practice.

Insight into the Potential Mechanisms of Endocrine Disruption by Dietary Phytoestrogens in the Context of the Etiopathogenesis of Endometriosis

Phytoestrogens (PEs) are estrogen-like nonsteroidal compounds derived from plants (e.g., nuts, seeds, fruits, and vegetables) and fungi that are structurally similar to 17β-estradiol. PEs bind to all types of estrogen receptors, including ERα and ERβ receptors, nuclear receptors, and a membrane-bound estrogen receptor known as the G protein-coupled estrogen receptor (GPER). As endocrine-disrupting chemicals (EDCs) with pro- or antiestrogenic properties, PEs can potentially disrupt the hormonal regulation of homeostasis, resulting in developmental and reproductive abnormalities. However, a lack of PEs in the diet does not result in the development of deficiency symptoms. To properly assess the benefits and risks associated with the use of a PE-rich diet, it is necessary to distinguish between endocrine disruption (endocrine-mediated adverse effects) and nonspecific effects on the endocrine system. Endometriosis is an estrogen-dependent disease of unknown etiopathogenesis, in which tissue similar to the lining of the uterus (the endometrium) grows outside of the uterus with subsequent complications being manifested as a result of local inflammatory reactions. Endometriosis affects 10-15% of women of reproductive age and is associated with chronic pelvic pain, dysmenorrhea, dyspareunia, and infertility. In this review, the endocrine-disruptive actions of PEs are reviewed in the context of endometriosis to determine whether a PE-rich diet has a positive or negative effect on the risk and course of endometriosis.

In Memory of Ivo Brosens: Reflections on the Pathophysiology of Neonatal Uterine Bleeding

BACKGROUND

The occurrence of vaginal bleeding in early neonatal life has been observed for centuries and was considered a consequence of the sudden drop in circulating hormones following birth. As such, neonatal uterine bleeding was dismissed as having no clinical significance. Interest in the phenomenon was renewed when a new theory suggested a link between neonatal uterine bleeding (NUB) and accelerated endometrial maturation. This theory was based on the observation of a higher incidence of NUB in babies born post-term or after pregnancies complicated by intrauterine growth restriction, preeclampsia, or blood group incompatibility.

OBJECTIVE

The objective of this study was to review of available evidence on the pathogenesis of NUB.

METHOD

Review of available literature using Medline search (August 2022, no limit on start date or language) to identify articles that may link NUB with features of the uterus and/or endometrium.

OUTCOME

The fetal endometrial responses differ from that of the adult. In the fetus, the endometrium features progestogenic response only in a minority of cases. The endometrium in most newborn girls does not exhibit secretory or decidual changes which indicate lack of progesterone response. Most newborn girls do not have visible bleeding. Animal studies linked exogenous progestogen exposure during the period of organogenesis to poor endometrial gland development, progesterone resistance, and to alterations of reproductive performance. Although the fetal endometrium may not exhibit a full proliferative response, it is clearly sensitive to circulating estrogens. Molecular mechanisms involved in NUB may include "ontogenetic progesterone resistance."

CONCLUSION AND OUTLOOK

Endometrial development and its response to withdrawal of hormones at birth varies and may be affected by intrauterine stressors and gestational age. Factors that affect endometrial development during fetal life and in preterm neonates can have implications on future reproductive performance.

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.

Aberrant epigenetic regulation of estrogen and progesterone signaling at the level of endometrial/endometriotic tissue in the pathomechanism of endometriosis

Endometriosis is a term referring to a condition whereby the endometrial tissue is found outside the uterine cavity. This progressive and debilitating condition affects up to 15% of women of reproductive age. Due to the fact that endometriosis cells may express estrogen receptors (ERα, Erβ, GPER) and progesterone (P4) receptors (PR-A, PR-B), their growth, cyclic proliferation, and breakdown are similar to the processes occurring in the endometrium. The underlying etiology and pathogenesis of endometriosis are still not fully explained. The retrograde transport of viable menstrual endometrial cells with the retained ability to attach within the pelvic cavity, proliferate, differentiate and invade into the surrounding tissue explains the most widely accepted implantation theory. Endometrial stromal cells (EnSCs) with clonogenic potential constitute the most abundant population of cells within endometrium that resemble the properties of mesenchymal stem cells (MSCs). Accordingly, formation of the endometriotic foci in endometriosis may be due to a kind of EnSCs dysfunction. Increasing evidence indicates the underestimated role of epigenetic mechanisms in the pathogenesis of endometriosis. Hormone-mediated epigenetic modifications of the genome in EnSCs or even MSCs were attributed an important role in the etiopathogenesis of endometriosis. The roles of excess estrogen exposure and P4 resistance were also found to be crucial in the development of epigenetic homeostasis failure. Therefore, the aim of this review was to consolidate the current knowledge regarding the epigenetic background of EnSCs and MSCs and the changed properties due to estrogen/P4 imbalances in the context of the etiopathogenesis of endometriosis.

Adjustment of progesterone administration after endometrial transcriptomic analysis does not improve reproductive outcomes in women with adenomyosis

RESEARCH QUESTION

Do patients with adenomyosis present a dysregulated endometrial receptivity that can be reversed with personalized embryo transfer (PET) by transcriptomic-based progesterone adjustment, improving IVF outcomes?

DESIGN

A multicentre, retrospective, cohort study that transcriptomically analysed the endometrial receptivity of the endometrium in patients with adenomyosis (n = 81) and healthy women (n = 231). Subsequently, implantation, biochemical and clinical miscarriage, and live birth rates between adenomyosis patients with one previous implantation failure using donor oocytes who received (n = 59) or did not receive (n = 66) PET based on endometrial receptivity, were observed to evaluate if adjusted progesterone improves reproductive outcomes of adenomyosis patients.

RESULTS

Patients with adenomyosis significantly presented an altered endometrial receptivity (non-receptive) compared with healthy patients (53.1% versus 37.2%, P = 0.0179), elevating the risk of adenomyosis patients having a non-receptive endometrium 42.59% higher (95% CI 41.50 to 44.45). No significant differences were found in implantation (62.7% versus 78.8%, P = 0.0514), biochemical (13.5% versus 3.9%, P = 0.1223) and clinical (10.8% versus 15.4%, P = 0.7543) miscarriage, or live birth rates (75.7% versus 80.8%, P = 0.6066), in patients with PET compared with those without PET.

CONCLUSIONS

Women with adenomyosis presented an altered expression of genes involved in decidualization, and a higher rate of non-receptive endometrial statuses than controls. Although progesterone is indispensable for implantation, adjusting progesterone before PET, using endometrial transcriptomic signatures, does not improve IVF outcomes in patients with adenomyosis. Other molecular mechanisms beyond progesterone regulation may be involved in implantation failure.

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.

Derivation of hormone-responsive human endometrial organoids and stromal cells from cryopreserved biopsies

The human endometrium is a dynamic tissue that undergoes cyclic changes in response to sex steroid hormones to provide a receptive status for embryo implantation. Disruptions in this behavior may lead to implantation failure and infertility; therefore, it is essential to develop an appropriate in vitro model to study endometrial changes in response to sex hormones. In this regard, the first choice would be human endometrial cells isolated from biopsies that could be used as monolayer cell sheets or to generate endometrial organoids. However, the need for fresh samples and short-time viability of harvested endometrial biopsy limits these approaches. In order to overcome these limitations, we sought to develop an efficient, simple, robust and reproducible method to cryopreserve human endometrial biopsies that could be stored and/or shipped frozen and later thawed to generate endometrial organoids and endometrial stromal cells (EnSCs). These cryopreserved biopsies could be thawed and used to generate simple endometrial organoids or organoids for co-culture with matched stromal cells that are functionally responsive to sex hormones as similar as the organoids generated from fresh biopsy. An optimal endometrial tissue cryopreservation method would allow the possibility for endometrial tissue biobanking to enable future organoid generation from both healthy tissues and pathological conditions, and open new venues for generate endometrial assembloids, consisting of epithelial organoids and primary stromal cells.

Di-(2-ethylhexyl) Phthalate Triggers Proliferation, Migration, Stemness, and Epithelial-Mesenchymal Transition in Human Endometrial and Endometriotic Epithelial Cells via the Transforming Growth Factor-β/Smad Signaling Pathway

Di-(2-ethylhexyl) phthalate (DEHP) is a frequently used plasticizer that may be linked to the development of endometriosis, a common gynecological disorder with a profound impact on quality of life. Despite its prevalence, vital access to treatment has often been hampered by a lack of understanding of its pathogenesis as well as reliable disease models. Recently, epithelial–mesenchymal transition (EMT) has been suggested to have a significant role in endometriosis pathophysiology. In this study, we found that DEHP treatment enhanced proliferation, migration, and inflammatory responses, along with EMT and stemness induction in human endometrial and endometriotic cells. The selective transforming growth factor-β (TGF-β) receptor type 1/2 inhibitor LY2109761 reversed the DEHP-induced cell proliferation and migration enhancement as well as the increased expression of crucial molecules involved in inflammation, EMT, and stemness, indicating that DEHP-triggered phenomena occur via the TGF-β/Smad signaling pathway. Our study clearly defines the role of DEHP in the etiology and pathophysiological mechanisms of endometriosis and establishes an efficient disease model for endometriosis using a biomimetic 3D cell culture technique. Altogether, our data provide novel etiological and mechanistic insights into the role of DEHP in endometriosis pathogenesis, opening avenues for developing novel preventive and therapeutic strategies for endometriosis.

Quinagolide Treatment Reduces Invasive and Angiogenic Properties of Endometrial Mesenchymal Stromal Cells

Endometrial mesenchymal stromal cells (E-MSCs) extensively contribute to the establishment and progression of endometrial ectopic lesions through formation of the stromal vascular tissue, and support to its growth and vascularization. As E-MSCs lack oestrogen receptors, endometriosis eradication cannot be achieved by hormone-based pharmacological approaches. Quinagolide is a non-ergot-derived dopamine receptor 2 agonist reported to display therapeutic effects in in vivo models of endometriosis. In the present study, we isolated E-MSCs from eutopic endometrial tissue and from ovarian and peritoneal endometriotic lesions, and we tested the effect of quinagolide on their proliferation and matrix invasion ability. Moreover, the effect of quinagolide on E-MSC endothelial differentiation was assessed in an endothelial co-culture model of angiogenesis. E-MSC lines expressed dopamine receptor 2, with higher expression in ectopic than eutopic ones. Quinagolide inhibited the invasive properties of E-MSCs, but not their proliferation, and limited their endothelial differentiation. The abrogation of the observed effects by spiperone, a dopamine receptor antagonist, confirmed specific dopamine receptor activation. At variance, no involvement of VEGFR2 inhibition was observed. Moreover, dopamine receptor 2 activation led to downregulation of AKT and its phosphorylation. Of interest, several effects were more prominent on ectopic E-MSCs with respect to eutopic lines. Together with the reported effects on endometrial and endothelial cells, the observed inhibition of E-MSCs may increase the rationale for quinagolide in endometriosis treatment.

Establishment of Adenomyosis Organoids as a Preclinical Model to Study Infertility

Adenomyosis is related to infertility and miscarriages, but so far there are no robust in vitro models that reproduce its pathological features to study the molecular mechanisms involved in this disease. Endometrial organoids are in vitro 3D models that recapitulate the native microenvironment and reproduce tissue characteristics that would allow the study of adenomyosis pathogenesis and related infertility disorders. In our study, human endometrial biopsies from adenomyosis (n = 6) and healthy women (n = 6) were recruited. Organoids were established and hormonally differentiated to recapitulate midsecretory and gestational endometrial phases. Physiological and pathological characteristics were evaluated by immunohistochemistry, immunofluorescence, qRT-PCR, and ELISA. Secretory and gestational organoids recapitulated in vivo glandular epithelial phenotype (pan-cytokeratin, Muc-1, PAS, Laminin, and Ki67) and secretory and gestational features (α-tubulin, SOX9, SPP1, PAEP, LIF, and 17βHSD2 expression and SPP1 secretion). Adenomyosis organoids showed higher expression of TGF-β2 and SMAD3 and increased gene expression of SPP1, PAEP, LIF, and 17βHSD2 compared with control organoids. Our results demonstrate that organoids derived from endometria of adenomyosis patients and differentiated to secretory and gestational phases recapitulate native endometrial-tissue-specific features and disease-specific traits. Adenomyosis-derived organoids are a promising in vitro preclinical model to study impaired implantation and pregnancy disorders in adenomyosis and enable personalized drug screening.

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.

Traditionally, ovarian endometriomas are considered rightfully as one subtype of endometriosis that is different from other subtypes. Beyond that, it is considered as a monolithic disease entity. In this review, we synthesized published data and argue that this subtype actually has age‐dependent phenotypes, and as such, management should be ideally tailored to achieve the best results.

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.

A History of Neonatal Uterine Bleeding and Its Significance

Bleeding in newborns and young girls fascinated writers for more than a millennium. Initially, there was confusion between neonatal bleeding, early menstruation due to precocious puberty, and hemorrhage due to disease. During the 19th century descriptions appeared of what is referred to today as ‘neonatal menstruation’ or ‘neonatal uterine bleeding’. By the turn of the century, Halban linked bleeding to active substances present during pregnancy and hypothesized that, while the maternal uterus reacts with decidua formation, the “weaker” fetal uterus reacts only with menstrual-like changes. Despite this clear description, several alternative theories endured for decades. Bleeding was believed to be due to a ‘catarrhal’ or neoplastic state of the genital tract, pulmonary circulatory disorder, congenital heart malformations, closure of the umbilical cord or affections of the intestine. During the 1950s, progesterone response and resistance were proposed to explain the pathogenesis of bleeding and its low incidence. The fetal endometrium is resistant to the high circulating progesterone. A decidual response is infrequent and results in menstrual shedding upon progesterone withdrawal after birth. Further research linked fetal stress consequent to pregnancy complications and post-maturity to increased incidence and preterm birth to reduced incidence of neonatal uterine bleeding.

Uterine Adenomyosis: From Disease Pathogenesis to a New Medical Approach Using GnRH Antagonists

Uterine adenomyosis is a common chronic disorder frequently encountered in reproductive-age women, causing heavy menstrual bleeding, intense pelvic pain, and infertility. Despite its high prevalence, its etiopathogenesis is not yet fully understood, so there are currently no specific drugs to treat the disease. A number of dysregulated mechanisms are believed to contribute to adenomyosis development and symptoms, including sex steroid signaling, endometrial proliferation and invasiveness, and aberrant immune response. Abnormal sex steroid signaling, particularly hyperestrogenism and subsequent progesterone resistance, are known to play a pivotal role in its pathogenesis, which is why various antiestrogenic agents have been used to manage adenomyosis-related symptoms. Among them, gonadotropin-releasing hormone (GnRH) antagonists are swiftly gaining ground, with recent studies reporting efficient lesion regression and symptom alleviation. The aim of the present review is to compile available information on the pathogenesis of adenomyosis, explore the etiology and mechanisms of hyperestrogenism, and discuss the potential of antiestrogenic therapies for treating the disease and improving patient quality of life.

Malignant transformation of abdominal wall endometriosis: A systematic review of the epidemiology, diagnosis, treatment, and outcomes

Malignant transformation of abdominal wall endometriosis (AWE) is rare. The clinical characteristics and treatment of malignant transformation of AWE are not well known. Therefore, in this review, we performed a thorough search for malignant transformation of AWE on MEDLINE and Web of Science from their inception to May 2021. In total, the data of 46 patients with malignant transformation of AWE were retrieved, and all the data on these patients were collected. After reviewing and analyzing the clinical parameters, we found that cesarean scar was the most common site of malignant transformation of AWE, and the most common pathological type of malignant transformation of AWE was clear cell cancer, followed by endometrioid adenocarcinoma. The main symptoms of malignant transformation of AWE included an abdominal nodule or mass, and ultrasonography was the first choice for diagnosis. The most widely accepted treatment was surgical resection of local lesions with adjunctive chemotherapy and/or radiotherapy, and the overall survival of patients with malignant transformation of AWE was poor. In conclusion, malignant transformation of AWE is rare, and the prognosis is poor. Thus, improving abdominal surgical technology and avoiding iatrogenic ectopia and implantation of the endometrium are necessary to prevent malignant transformation of AWE.

Estrogen- and Progesterone (P4)-Mediated Epigenetic Modifications of Endometrial Stromal Cells (EnSCs) and/or Mesenchymal Stem/Stromal Cells (MSCs) in the Etiopathogenesis of Endometriosis

Endometriosis is a common chronic inflammatory condition in which endometrial tissue appears outside the uterine cavity. Because ectopic endometriosis cells express both estrogen and progesterone (P4) receptors, they grow and undergo cyclic proliferation and breakdown similar to the endometrium. This debilitating gynecological disease affects up to 15% of reproductive aged women. Despite many years of research, the etiopathogenesis of endometrial lesions remains unclear. Retrograde transport of the viable menstrual endometrial cells with retained ability for attachment within the pelvic cavity, proliferation, differentiation and subsequent invasion into the surrounding tissue constitutes the rationale for widely accepted implantation theory. Accordingly, the most abundant cells in the endometrium are endometrial stromal cells (EnSCs). These cells constitute a particular population with clonogenic activity that resembles properties of mesenchymal stem/stromal cells (MSCs). Thus, a significant role of stem cell-based dysfunction in formation of the initial endometrial lesions is suspected. There is increasing evidence that the role of epigenetic mechanisms and processes in endometriosis have been underestimated. The importance of excess estrogen exposure and P4 resistance in epigenetic homeostasis failure in the endometrial/endometriotic tissue are crucial. Epigenetic alterations regarding transcription factors of estrogen and P4 signaling pathways in MSCs are robust in endometriotic tissue. Thus, perspectives for the future may include MSCs and EnSCs as the targets of epigenetic therapies in the prevention and treatment of endometriosis. Here, we reviewed the current known changes in the epigenetic background of EnSCs and MSCs due to estrogen/P4 imbalances in the context of etiopathogenesis of endometriosis. Graphical Abstract.

Use of dopamine agonists to target angiogenesis in women with endometriosis

Endometriosis requires medical management during a woman's reproductive years. Most treatments aim to create a hypoestrogenic milieu, but for patients wishing to conceive, drugs that allow normal ovarian function are needed. Targeting angiogenesis, a hallmark of the disease, using dopamine agonists (DAs) is a promising strategy for endometriosis treatment. Herein, we review experimental and clinical data that investigate this concept. In experimental models of endometriosis, DAs (bromocriptine, cabergoline, quinagolide) downregulate proangiogenic and upregulate antiangiogenic pathways in inflammatory, endothelial and endometrial cells, blocking cellular proliferation and reducing lesion size. Impaired secretion of vascular endothelial growth factor (VEGF) and inactivation of its receptor type-2 are key events. VEGF inhibition also reduces nerve fiber density in lesions. In humans, quinagolide shows similar effects on lesions, and DAs reduce pain and endometrioma size. Moreover, a 20-fold downregulation of Serpin-1, the gene that encodes for plasminogen activator inhibitor 1 (PAI-1), has been observed after DAs treatment. Pentoxifylline, a PAI-1, increases pregnancy rates in women with endometriosis. Thus, the data support the use of DAs in the medical management of endometriosis to reduce lesion size and pain while maintaining ovulation. A combined approach of DAs and pentoxifylline is perhaps a smart way of targeting the disease from a completely different angle than current medical treatments.

Combating Diagnostic Delay of Endometriosis in Adolescents via Educational Awareness: A Systematic Review

Endometriosis occurs in approximately 10% of adult women worldwide; however, it is commonly under- or misdiagnosed in adolescents. The purpose of this study was to analyze existing scientific literature for reasons for diagnostic delay of endometriosis and to determine how education regarding endometriosis could be improved. An integrative review was conducted based on articles published between December 1980 and December 2020. Suitable articles were identified from the MEDLINE/PubMed databases, using relevant terms. Eligible studies included discussion on potential causes of diagnostic delay of endometriosis in the adolescent population. Data were extracted from eligible publications and qualitative synthesis was used. The 27 articles included in the study revealed several primary reasons for the delay, such as a physician and/or patient knowledge gap, normalization by physician and patient, lack of research, and physician resistance. Strategies to lessen diagnostic delay of endometriosis in adolescents must include integrated actions by educators and healthcare providers to improve health literacy and awareness of common causes of pelvic pain in this age group.

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.

Endometriosis in adolescent and young women

Endometriosis in adolescence represents a specific variant of the disease with its own characteristics and, in some cases, even a possibly different pathogenesis. It has its own clinical presentation, diagnostic and therapeutic modalities. The condition is not rare as once thought and certainly deserves attention in view of increasing evidence of its likely progressive nature. Numerous theories for Its pathogenesis have been formulated and they have been divided into two main categories: the 'in-situ' and the 'transplantation' hypotheses. Clinical manifestations include as the prevailing symptom a persistent chronic pelvic pain, despite medical treatment, manifested under various forms: dysmenorrhea, acyclic chronic pain, acute abdominal pain and migraines. These symptoms can substantially affect the quality of life on an adolescent. At histopathology, adolescent endometriosis is characterized by a high proportion of subtle, clear, red or vesicular implants and by the rarity of deep nodules. Frequently, the picture includes ovarian endometriomas. In some adolescent girls, lesions may regress or even disappear, probably through immune suppression; in others, chronic stress, unhealthy diet or lifestyle such as high-fat diet, may accelerate lesional progression and cause symptoms. Classically, management of adolescent endometriosis has been centered on attempts to treat dysmenorrhea; today both medical and surgical modalities have the potential to improve quality of life, alleviate symptoms, prevent the development of more severe disease and minimize risks for future fertility in adolescents. Nonetheless, at present, medical treatments are considered the first line of interventions in treating young women.

In vivo effects of AZD4547, a novel fibroblast growth factor receptor inhibitor, in a mouse model of endometriosis

Endometriosis is a chronic disease, characterized by the growth of endometrial-like cells outside the uterine cavity. Due to its complex pathophysiology, a totally resolving cure is yet to be found. The aim of this study was to compare the therapeutic efficacy of AZD4547, a novel fibroblast growth factor receptor inhibitor (FGFRI), with a well-characterized progestin, etonogestrel (ENG) using a validated in vivo mouse model of endometriosis. Endometriosis was induced by transplanting uterine fragments from donor mice in proestrus into the peritoneal cavity of recipient mice, which then developed into cyst-like lesions. AZD4547 and ENG were administered systemically either from the day of endometriosis induction or 2-weeks post-surgery. After 20 days of treatment, the lesions were harvested; their size and weight were measured and analyzed histologically or by qRT-PCR. Stage of estrous cycle was monitored throughout. Compared to vehicle, AZD4547 (25 mg/kg) was most effective in counteracting lesion growth when treating from day of surgery and 2 weeks after; ENG (0.8 mg/kg) was similarly effective in reducing lesion growth but only when administered from day of surgery. Each downregulated FGFR gene expression (p < 0.05). AZD4547 at all doses and ENG (0.008 mg/kg) caused no disturbance to the estrous cycle. ENG at 0.08 and 0.8 mg/kg was associated with partial or complete estrous cycle disruption and hyperemia of the uteri. AZD4547 and ENG both attenuated endometriotic lesion size, but only AZD4547 did not disrupt the estrous cycle, suggesting that targeting of FGFR is worthy of further investigation as a novel treatment for endometriosis.

Organoids of the female reproductive tract

Healthy functioning of the female reproductive tract (FRT) depends on balanced and dynamic regulation by hormones during the menstrual cycle, pregnancy and childbirth. The mucosal epithelial lining of different regions of the FRT-ovaries, fallopian tubes, uterus, cervix and vagina-facilitates the selective transport of gametes and successful transfer of the zygote to the uterus where it implants and pregnancy takes place. It also prevents pathogen entry. Recent developments in three-dimensional (3D) organoid systems from the FRT now provide crucial experimental models that recapitulate the cellular heterogeneity and physiological, anatomical and functional properties of the organ in vitro. In this review, we summarise the state of the art on organoids generated from different regions of the FRT. We discuss the potential applications of these powerful in vitro models to study normal physiology, fertility, infections, diseases, drug discovery and personalised medicine.

Management Challenges of Deep Infiltrating Endometriosis

Deep infiltrating endometriosis (DIE) is the most aggressive of the three phenotypes that constitute endometriosis. It can affect the whole pelvis, subverting the anatomy and functionality of vital organs, with an important negative impact on the patient's quality of life. The diagnosis of DIE is based on clinical and physical examination, instrumental examination, and, if surgery is needed, the identification and biopsy of lesions. The choice of the best therapeutic approach for women with DIE is often challenging. Therapeutic options include medical and surgical treatment, and the decision should be dictated by the patient's medical history, disease stage, symptom severity, and personal choice. Medical therapy can control the symptoms and stop the development of pathology, keeping in mind the side effects derived from a long-term treatment and the risk of recurrence once suspended. Surgical treatment should be proposed only when it is strictly necessary (failed hormone therapy, contraindications to hormone treatment, severity of symptoms, infertility), preferring, whenever possible, a conservative approach performed by a multidisciplinary team. All therapeutic possibilities have to be explained by the physicians in order to help the patients to make the right choice and minimize the impact of the disease on their lives.

Stem Cells and the Endometrium: From the Discovery of Adult Stem Cells to Pre-Clinical Models

Adult stem cells (ASCs) were long suspected to exist in the endometrium. Indeed, several types of endometrial ASCs were identified in rodents and humans through diverse isolation and characterization techniques. Putative stromal and epithelial stem cell niches were identified in murine models using label-retention techniques. In humans, functional methods (clonogenicity, long-term culture, and multi-lineage differentiation assays) and stem cell markers (CD146, SUSD2/W5C5, LGR5, NTPDase2, SSEA-1, or N-cadherin) facilitated the identification of three main types of endogenous endometrial ASCs: stromal, epithelial progenitor, and endothelial stem cells. Further, exogenous populations of stem cells derived from bone marrow may act as key effectors of the endometrial ASC niche. These findings are promoting the development of stem cell therapies for endometrial pathologies, with an evolution towards paracrine approaches. At the same time, promising therapeutic alternatives based on bioengineering have been proposed.

Endometriosis and Medical Therapy: From Progestogens to Progesterone Resistance to GnRH Antagonists: A Review

Background: The first objective of this review was to present, based on recent literature, the most frequently applied medical options (oral contraceptive pills (OCPs) and progestogens) for the management of symptomatic endometriosis, and evaluate their effectiveness in treating premenopausal women with endometriosis-associated pelvic pain, dysmenorrhea, non-menstrual pelvic pain and dyspareunia. The second objective was to review the concept of progesterone resistance and newly available treatment options. Methods: We reviewed the most relevant papers (n = 73) on the efficacy of OCPs and progestogens as medical therapy for endometriosis, as well as those on progesterone resistance and new medical alternatives (oral gonadotropin-releasing hormone (GnRH) antagonist). Eleven papers, essentially reviews, were selected and scrutinized from among 94 papers discussing the concept of progesterone resistance. Results: Having reviewed the most significant papers, we can confirm that OCPs and progestogens are effective in two-thirds of women suffering from endometriosis, but that other options are required in case of failure (in one-third of women due to progesterone resistance) or intolerance to these compounds. It is clear that there is a need for effective long-term oral treatment capable of managing endometriosis symptoms, while mitigating the impact of side effects. Biochemical, histological and clinical evidence show that estrogens play a critical role in the pathogenesis of endometriosis, so lowering levels of circulating estrogens should be considered an effective medical approach. The efficacy of three oral GnRH antagonists is discussed on the basis of published studies. Conclusion: There is a place for GnRH antagonists in the management of symptomatic endometriosis and clinical trials should be conducted, taking into account the different phenotypes in order to propose novel algorithms.

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.

Reproductive health research in Australia and New Zealand: highlights from the Annual Meeting of the Society for Reproductive Biology, 2019

The 2019 meeting of the Society for Reproductive Biology (SRB) provided a platform for the dissemination of new knowledge and innovations to improve reproductive health in humans, enhance animal breeding efficiency and understand the effect of the environment on reproductive processes. The effects of environment and lifestyle on fertility and animal behaviour are emerging as the most important modern issues facing reproductive health. Here, we summarise key highlights from recent work on endocrine-disrupting chemicals and diet- and lifestyle-induced metabolic changes and how these factors affect reproduction. This is particularly important to discuss in the context of potential effects on the reproductive potential that may be imparted to future generations of humans and animals. In addition to key summaries of new work in the male and female reproductive tract and on the health of the placenta, for the first time the SRB meeting included a workshop on endometriosis. This was an important opportunity for researchers, healthcare professionals and patient advocates to unite and provide critical updates on efforts to reduce the effect of this chronic disease and to improve the welfare of the women it affects. These new findings and directions are captured in this review.

The Importance of Stromal Endometriosis in Thoracic Endometriosis

Thoracic endometriosis (TE) is a rare type of endometriosis, where endometrial tissue is found in or around the lungs and is frequent among extra-pelvic endometriosis patients. Catamenial pneumothorax (CP) is the most common form of TE and is characterized by recurrent lung collapses around menstruation. In addition to histology, immunohistochemical evaluation of endometrial implants is used more frequently. In this review, we compared immunohistochemical (CPE) with histological (CPH) characterizations of TE/CP and reevaluated arguments in favor of the implantation theory of Sampson. A summary since the first immunohistochemical description in 1998 until 2019 is provided. The emphasis was on classification of endometrial implants into glands, stroma, and both together. The most remarkable finding is the very high percentage of stromal endometriosis of 52.7% (CPE) compared to 10.2% (CPH). Chest pain, dyspnea, right-sided preference, and diaphragmatic endometrial implants showed the highest percentages in both groups. No significant association was found between the recurrence rate and the various appearances of endometriosis. Sometimes in CPE (6.8%) and CPH (30.6%) no endometrial implants were identified underlining the importance of sensitive detection of endometriosis during and after surgery. We suggest that immunohistochemical evaluation should become mandatory and will improve diagnosis and classification of the disease.

Neonatal Uterine Bleedings: An Ignored Sign but a Possible Cause of Early-Onset Endometriosis - A Systematic Review

OBJECTIVE

Based on the hypothesis that neonatal uterine bleedings (NUB), occurring mostly in the first week after birth, could represent a pathogenetic mechanism for early-onset endometriosis, this systematic review (SR) was undertaken to evaluate the prevalence and screening strategies used to assess and quantify NUB.

DESIGN

Both a SR and a sample literature search in PubMed and Embase were conducted to gather information on NUB prevalence and screening techniques. This was performed by an information specialist. Only full-text articles regarding the assessment of NUB in neonates in the first 2 weeks after birth were included. No limit on language or publication data was used.

MATERIALS AND METHODS

The SR was registered in PROSPERO (CRD42019138121). Data was first assessed for eligibility on title and abstract by 2 blinded review authors. Any disagreements were discussed with a third reviewer if necessary. Subsequently, full-text articles were read and assessed for quality using the Cochrane Collaboration Handbook.

RESULTS

Out of 1,988 articles in the systematic search, 10 relevant articles were selected, of which 8 were identified through the systematic search and 2 were found through other sources. The sample search of 4,445 articles did not bring up relevant articles. Results were not comparable due to the heterogeneity of screening techniques, although data showed consensus. The prevalence of visible bleeding ranged from 3.3 to 53.8% and the prevalence of occult bleeding from 25.4 to 96.7%. The occurrence was the highest between the 3rd and 7th day postpartum (PP) and the bleeding lasted for 3-4 days on average. Various screening techniques for detecting NUB were found in the literature, including the use of hemoglobin detection devices (such as Hemastix) in the vaginal vestibulum, comparison of diapers with stains of known volume, colposcopy, and ultrasonography.

CONCLUSION

The reported prevalence of NUB varies considerably, with a consistent occurrence between the 3rd and the 7th day PP. Literature to assess NUB is dated. The techniques are poorly described and heterogeneous. Future research should focus on prospective cohort studies in order to attempt to correlate NUB cases to (early-onset) endometriosis.

Cellular Origins of Endometriosis: Towards Novel Diagnostics and Therapeutics

Endometriosis remains an enigmatic disease of unknown etiology, with delayed diagnosis and poor therapeutic options. This review will discuss the cellular, physiological, and genomic evidence of Sampson's hypothesis of retrograde menstruation as a cause of pelvic endometriosis and as the basis of phenotypic heterogeneity of the disease. We postulate that collaborative research at the single cell level focused on unlocking the cellular, physiological, and genomic mechanisms of endometriosis will be accompanied by advances in personalized diagnosis and therapies that target unique subtypes of endometriosis disease. These advances will address the clinical conundrums of endometriosis clinical care—including diagnostic delay, suboptimal treatments, disease recurrence, infertility, chronic pelvic pain, and quality of life. There is an urgent need to improve outcomes for women with endometriosis. To achieve this, it is imperative that we understand which cells form the lesions, how they arrive at distant sites, and what factors govern their ability to survive and invade at ectopic locations. This review proposes new research avenues to address these basic questions of endometriosis pathobiology that will lay the foundations for new diagnostic tools and treatment pathways.

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.

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.

CD34+KLF4+ Stromal Stem Cells Contribute to Endometrial Regeneration and Repair

The regenerative capacity of the human endometrium requires a population of local stem cells. However, the phenotypes, locations, and origin of these cells are still unknown. In a mouse menstruation model, uterine stromal SM22α⁺-derived CD34⁺KLF4⁺ stem cells are activated and integrate into the regeneration area, where they differentiate and incorporate into the endometrial epithelium; this process is correlated with enhanced protein SUMOylation in CD34⁺KLF4⁺ cells. Mice with a stromal SM22α-specific SENP1 deletion (SENP1smKO) exhibit accelerated endometrial repair in the regeneration model and develop spontaneous uterine hyperplasia. Mechanistic studies suggest that SENP1 deletion induces SUMOylation of ERα, which augments ERα transcriptional activity and proliferative signaling in SM22α⁺CD34⁺KLF4⁺ cells. These cells then transdifferentiate to the endometrial epithelium. Our study reveals that CD34⁺KLF4⁺ stromal-resident stem cells directly contribute to endometrial regeneration, which is regulated through SENP1-mediated ERα suppression.

The regenerative capacity of the human endometrium requires a population of local stem cells. Here, Yin et al. show that uterine stromal SM22α⁺CD34⁺KLF4⁺ stem cells are activated by ERα SUMOylation and integrate into the regeneration area, where they differentiate and incorporate into the endometrial epithelium.

Epithelial-Mesenchymal Transition in Endometriosis-When Does It Happen?

Epithelial-mesenchymal transition (EMT) is an important process of cell remodeling characterized by the gradual loss of the epithelial phenotype and progressive gain of a mesenchymal phenotype. EMT is not an all-or-nothing process, but instead a transition of epithelial to mesenchymal cells with intermediate cell states. Recently, EMT was described in endometriosis, and many EMT-specific pathways like Twist, Snail, Slug, Zinc finger E-box-binding homeobox 1/2 (ZEB1/2), E/N-cadherin, keratins, and claudins are involved. However, as pointed out in this review, a comparison of the eutopic endometrium of women with and without endometriosis yielded only subtle changes of these EMT markers. Furthermore, only very few alterations in cell-cell contacts could be found but without changes in the epithelial phenotype. This suggests only a partial EMT which is not a prerequisite for the detachment of endometrial cells and, thus, not critical for the first step(s) in the pathogenesis of endometriosis. In contrast, the majority of changes in the EMT-related marker expression were found in the ectopic endometrium, especially in the three endometriotic entities, ovarian, peritoneal, and deep infiltrating endometriosis (DIE), compared with the eutopic endometrium. In this review, we examine the most important EMT pathways described in endometriosis and propose that partial EMT might result from the interaction of endometrial implants with their surrounding microenvironment.

Immunoreactivity of Kisspeptin and Kisspeptin Receptor in Eutopic and Ectopic Endometrial Tissue of Women With and Without Endometriosis

Endometriosis is characterized by the presence of ectopic endometrial tissues. Mechanisms of tissue dissemination in endometriosis may be similar to those involved in tumor metastasis. We hypothesize that dysregulation of kisspeptin (KISS1), a metastasis suppressor in endometrial carcinoma, may contribute to the pathogenesis of endometriosis. In this study, we characterized the immunoreactivity of kisspeptin and its receptor, KISS1R, in eutopic and ectopic endometrial tissue of women with and without endometriosis, in proliferative and secretory menstrual cycle phases. Immunohistochemistry was performed using KISS1 and KISS1R antibodies on samples from women with (n = 35) and without (n = 14) endometriosis. Samples from women with endometriosis included eutopic endometrium (n = 20) samples, superficial endometriotic implants (SUP, n = 10) deep infiltrating endometriotic implants (DIE, n = 15), and ovarian endometriomas (OMA, n = 15). Immunoreactivity was quantified using histoscores. KISS1 and KISS1R immunoreactivity was significantly lower in eutopic endometrial stroma of women with versus without endometriosis, regardless of the menstrual cycle phase (P = 0.001 and P = 0.015 respectively). In endometriotic implants, KISS1 levels were significantly lower in both glandular and stromal components of DIE (P < 0.01) and OMA (P < 0.01) compared to SUP. KISS1R immunoreactivity was lower in the glandular component of OMA (P = 0.035) compared to SUP. KISS1 and KISS1R levels are lower in eutopic endometrial stroma from women with versus without endometriosis, consistent with a role for decreased KISS1 expression in the pathogenesis of endometriosis. As deeply invasive lesions showed lower KISS1 levels than superficial lesions, downregulation of KISS1 levels may contribute to implant invasiveness.

Transcriptome meta-analysis reveals differences of immune profile between eutopic endometrium from stage I-II and III-IV endometriosis independently of hormonal milieu

Eutopic endometrium appears to be crucial for endometriosis development. Despite of the evident importance, data regarding the cellular microenvironment remain unclear. Our objective was to explore the tissue microenvironment heterogeneity, transcripts, and pathways that are enriched in all phases of the menstrual cycle by analysing publicly deposited data derived from whole transcriptome microarrays of eutopic endometria of women with and without endometriosis. A meta-analysis of the transcriptome microarrays was performed using raw data available from a public database. Eligibility criteria included eutopic endometrium samples from women with endometriosis and healthy controls without any pathological condition reported the presence of an adequately reported normal menstrual phase, and samples containing both glandular and stromal components. Raw data were processed using a robust multiarray average method to provide background correction, normalisation, and summarisation. The batch effect was estimated by principal variant component analysis and removed using an empirical Bayes method. Cellular tissue heterogeneity was inferred using the xCell package. Differentially expressed genes were identified based on a 5% adjusted p value and a 2.0-fold change. Pathways were identified by functional enrichment based on the Molecular Signatures Database, a p value of < 5%, and an FDR q value of ≤ 25%. Genes that were more frequently found in pathways were identified using leading edge analysis. In a manner independent of cycle phase, the subpopulations of activated dendritic cells, CD4 T effector memory phenotype cells, eosinophils, macrophages M1, and natural killer T cells (NKT) were all higher in stage I-II endometriosis compared to those in healthy controls. The subpopulations of M2 macrophages and natural killer T cells were elevated in eutopic endometriums from women with stage III-IV endometriosis, and smooth muscle cells were always more prevalent in healthy eutopic endometriums. Among the differently expressed genes, FOS, FOSB, JUNB, and EGR1 were the most frequently mapped within the interaction networks, and this was independent of stage and cycle phase. The enriched pathways were directly related to immune surveillance, stem cell self-renewal, and epithelial mesenchymal transition. PI3K AKT mTOR, TGF signalling, and interferon alpha/gamma responses were enriched exclusively in stage III-IV endometriosis. The cellular microenvironments and immune cell profiles were different between eutopic endometriums from women with stage I-II and stage III-IV endometriosis, and these differences were independent of the hormonal milieu. Specifically, a pro-inflammatory profile was predominant in stage I-II endometriosis, and M1-M2 polarization into eutopic endometrium may be crucial for the progression of the disease. The higher prevalence of NKT cells in eutopic endometriums from women with endometriosis that was independent of cycle phase or staging suggested a sustained stress and/or damage to these eutopic endometriums. Based on this, the results of this meta-analysis are important for identifying challenges and opportunities for future research.

Recent advances in mammalian reproductive biology

Reproductive biology is a uniquely important topic since it is about germ cells, which are central for transmitting genetic information from generation to generation. In this review, we discuss recent advances in mammalian germ cell development, including preimplantation development, fetal germ cell development and postnatal development of oocytes and sperm. We also discuss the etiologies of female and male infertility and describe the emerging technologies for studying reproductive biology such as gene editing and single-cell technologies.

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.

Association between Sexual Activity during Menstruation and Endometriosis: A Case-Control Study

Background

The prevalence of endometriosis in the general population is estimated at 7-10%. There are various risk factors for this disease, including early menarche age, prolonged menstruation or no history of pregnancy. It seems that sexual activity leading to orgasm during menstruation increases the retrograde menstruation, sending endometrial tissue to an abnormal sites and thus increasing the risk of endometriosis. The present study is aimed to determine the association between sexual activity during menstruation and endometriosis.

Materials and Methods

This case-control study, conducted in the year 2017, recruited 555 women who were visited at Alzahra Hospital in Tabriz, Northwest of Iran. The case group comprised 185 women of reproductive age with confirmed endometriosis. The control group comprised 370 women of reproductive age without endometriosis visit- ing the hospital for other issues. Data was collected using a researcher-made questionnaire based on previous studies. Bivariate analysis was performed by the chi-squared test and multivariate analysis was done using conditional logistic regression to control confounding variables.

Results

The sexual activity of the two groups during menstruation was significantly different. The occurrence of endometriosis in women who stated they had vaginal intercourse or non-coital sexual activities, leading to orgasm during menstruation, was significantly higher compared to those who stated they did not.

Conclusion

According to our findings, there is an association between sexual activities leading to orgasm during menstruation and endometriosis.

Aberrant expression of genes associated with stemness and cancer in endometria and endometrioma in a subset of women with endometriosis

STUDY QUESTION

Is there molecular evidence for a link between endometriosis and endometriosis-associated ovarian cancers (EAOC)?

STUDY ANSWER

We identified aberrant gene expression signatures associated with malignant transformation in a small subgroup of women with ovarian endometriosis.

WHAT IS KNOWN ALREADY

Epidemiological studies have shown an increased risk of EAOC in women with ovarian endometriosis. However, the cellular and molecular changes leading to EAOC are largely unexplored.

STUDY DESIGN, SIZE, DURATION

CD73+CD90+CD105+ multipotent stem cells/progenitors (SC cohort) were isolated from endometrium (n = 18) and endometrioma (n = 11) of endometriosis patients as well as from the endometrium of healthy women (n = 14). Extensive phenotypic and functional analyses were performed in vitro on expanded multipotent stem cells/progenitors to confirm their altered characteristics. Aberrant gene signatures were also validated in paired-endometrium and -endometrioma tissue samples from another cohort (Tissue cohort, n = 19) of endometriosis patients.

PARTICIPANTS/MATERIALS, SETTINGS, METHODS

Paired-endometrial and -endometriotic biopsies were obtained from women with endometriosis (ASRM stage III-IV) undergoing laparoscopic surgery. Control endometria were obtained from healthy volunteers. Isolated CD73+CD90+CD105+ SC were evaluated for the presence of known endometrial surface markers, colony forming efficiency, multi-lineage differentiation, cell cycle distribution and 3D-spheroid formation capacity. Targeted RT-PCR arrays, along with hierarchical and multivariate clustering tools, were used to determine both intergroup and intragroup gene expression variability for stem cell and cancer-associated markers, in both SC+ and tissue cohorts.

MAIN RESULTS AND THE ROLE OF CHANCE

Isolated and expanded SC+ from both control and patient groups showed significantly higher surface expression of W5C5+, clonal expansion and 3D-spheroid formation capacity (P < 0.05) compared with SC-. The SC+ cells also undergo mesenchymal lineage differentiation, unlike SC-. Gene expression from paired-endometriosis samples showed significant downregulation of PTEN, ARID1A and TNFα (P < 0.05) in endometrioma compared with paired-endometrium SC+ samples. Hierarchical and multivariate clustering from both SC+ and tissue cohorts together identified 4 out of 30 endometrioma samples with aberrant expression of stem cell and cancer-associated genes, such as KIT, HIF2α and E-cadherin, altered expression ratio of ER-β/ER-α and downregulation of tumour suppressor genes (PTEN and ARID1A). Thus, we speculate that above changes may be potentially relevant to the development of EAOC.

LARGE-SCALE DATA

N/A.

LIMITATIONS, REASON FOR CAUTION

As the reported frequency of EAOC is very low, we did not have access to those samples in our study. Moreover, by adopting a targeted gene array approach, we might have missed several other potentially-relevant genes associated with EAOC pathogenesis. The above panel of markers should be further validated in archived tissue samples from women with endometriosis who later in life developed EAOC.

WIDER IMPLICATIONS OF THE FINDINGS

Knowledge gained from this study, with further confirmation on EAOC cases, may help in developing screening methods to identify women with increased risk of EAOC.

STUDY FUNDING/COMPETING INTEREST(S)

The study is funded by the Swedish Research Council (2012-2844), a joint grant from Stockholm County and Karolinska Institutet (ALF), RGD network at Karolinska Institutet, Karolinska Institutet for doctoral education (KID), Estonian Ministry of Education and Research (IUT34-16), Enterprise Estonia (EU48695), Horizon 2020 innovation program (WIDENLIFE, 692065), European Union's FP7 Marie Curie Industry-Academia Partnerships and Pathways funding (IAPP, SARM, EU324509) and MSCA-RISE-2015 project MOMENDO (691058). All authors have no competing interest.

Modern approaches to surgical management of endometrioma

Formation of the ovarian endometrioma consists of implantation, invagination of the ovarian cortex, and adhesion formation. Progression is characterized by repeated injury and repair with degenerative changes. Already with a partially deprived ovarian reserve, resulting from the disease, surgical treatment carries a potential risk of further follicular deprivation. Surgery should therefore be performed with microsurgical precision by experienced hands. Early treatment can possibly prevent further progression. The adverse impact on ovarian reserve of the ablative approach has to be balanced against a lower recurrence rate of a cystectomy. Adapted surgical approaches like a two-step approach or a combination of excisional and ablative surgery has to be considered in case of a large endometrioma. Further studies on the possibility and advantages of sclerotherapy are warranted. Fertility preservation by cryopreservation of ovarian cortex should be part of the informed consent with the patient.