Bone Marrow Stem Cell Chemotactic Activity Is Induced by Elevated CXCl12 in Endometriosis

Case report: A rare cause of intestinal perforation in a third-trimester pregnant woman

Background

An acute abdomen is a medical emergency that requires early diagnosis and treatment. In pregnancy, this process is significantly more challenging, and radiological findings are sometimes unclear due to the enlarged uterus displacing other structures. Moreover, endometriosis-related complications are rare, and the disease is often undiagnosed.

Case presentation

We report a case of acute perforation of the cecum and appendix during pregnancy (35 weeks of gestation) caused by a previously unknown, deep infiltrating endometriosis with focal ulceration of the affected bowel wall, which sonographically seemed to be acute appendicitis.

Conclusion

Despite the relatively low risk, clinicians should be aware of possible endometriosis-associated complications in pregnancy with potentially life-threatening events, even in previously unknown endometriosis. Further studies should evaluate intestinal complications during pregnancy in relation to previous treatment of intestinal endometriosis (conservative vs. surgical).

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

Background

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

Methods

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

Results

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

Conclusion

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

Autoimmune Disease-Related Hub Genes are Potential Biomarkers and Associated with Immune Microenvironment in Endometriosis

Background

Endometriosis, a common gynecological condition, can cause symptoms such as dysmenorrhea, infertility, and abnormal bleeding, which can negatively affect a woman's quality of life. In the current study, the pathophysiological mechanisms of endometriosis are unknown, but this study suggests that endometriosis is associated with dysregulation of the autoimmune system. This study identify hub genes involved in the prevalence, identification and diagnostic value of endometriosis and autoimmune diseases, and explore the central genes and immune infiltrates, the diagnosis of endometriosis provides a new sight of thinking about diagnosis and treatment.

Methods and Results

The relevant datasets for endometriosis GSE141549, GSE7305 and autoimmune disease-related genes (AIDGs) were downloaded from online database. Using the "limma" package and WGCNA to screen out the autoimmune disease related genes and endometriosis related genes, the autoimmune disease gene-related differential genes (AID-DEGs) progressive GO, KEGG enrichment analysis, and then using the protein interaction network and Cytoscape software to select hub genes (CXCL12, PECAM1, NGF, CTGF, WNT5A), using the "pROC" package to analyze the hub genes for the diagnostic value of endometriosis. The difference in the importance of hub genes for the diagnosis of endometriosis was analyzed by machine learning random forest, and the combined diagnostic value of hub genes was analyzed by using the Support Vector Machine (SVM) algorithm. The eutopic (EU) and ectopic endometrium (EC) immune microenvironment of endometriosis was evaluated using CIBERSORT, the correlation of hub genes to the immune microenvironment was analyzed.

Conclusion

The hub genes associated with AIDGs are differentially expressed in EC and EU of endometriosis and possess important value for the diagnosis of endometriosis. The hub genes have a very important impact on the immune microenvironment of endometriosis, which is important for exploring the connection between endometriosis and autoimmune diseases and provides a new insight for the subsequent study of immunotherapy and diagnosis of endometriosis.

Fortifying angiogenic efficacy of conditioned media using phototoxic-free blue light for wound healing

We used a blue organic light-emitting diode (bOLED) to increase the paracrine factors secreted from human adipose-derived stem cells (hADSCs) for producing conditioned medium (CM). Our results showed that while the bOLED irradiation promotes a mild-dose reactive oxygen generation that enhances the angiogenic paracrine secretion of hADSCs, it does not induce phototoxicity. The bOLED enhances paracrine factors via a cell-signaling mechanism involving hypoxia-inducible factor 1 alpha. This study demonstrated that the CM resulting from bOLED treatment shows improved therapeutic effects on mouse wound-healing models. This method contributes to overcoming the barriers to stem-cell therapies, including the toxicity and low yields from other methods such as nanoparticles, synthetic polymers, and even cell-derived vesicles.

Potential link between the nerve injury-induced protein (Ninjurin) and the pathogenesis of endometriosis

Endometriosis remains a widespread but severe gynecological disease in women of reproductive age, with an unknown etiology and few treatment choices. The menstrual reflux theory is largely accepted as the underlying etiology but does not explain the morbidity or unpleasant pain sensations of endometriosis. The neurological and immune systems are both involved in pain mechanisms of endometriosis, and interlinked through a complex combination of cytokines and neurotransmitters. Numerous pieces of evidence suggest that the nerve injury-inducible protein, Ninjurin, is actively expressed in endometriosis lesions, which contributes to the etiology and development of endometriosis. It may be explored in the future as a novel therapeutic target. The aim of the present review was to elucidate the multifaceted role of Ninjurin. Furthermore, we summarize the association of Ninjurin with the pain mechanism of endometriosis and outline the future research directions. A novel therapeutic pathway can be discovered based on the potential pathogenic variables.

Endometriosis-associated infertility: From pathophysiology to tailored treatment

Despite the clinically recognized association between endometriosis and infertility, the mechanisms implicated in endometriosis-associated infertility are not fully understood. Endometriosis is a multifactorial and systemic disease that has pleiotropic direct and indirect effects on reproduction. A complex interaction between endometriosis subtype, pain, inflammation, altered pelvic anatomy, adhesions, disrupted ovarian reserve/function, and compromised endometrial receptivity as well as systemic effects of the disease define endometriosis-associated infertility. The population of infertile women with endometriosis is heterogeneous, and diverse patients' phenotypes can be observed in the clinical setting, thus making difficult to establish a precise diagnosis and a single mechanism of endometriosis related infertility. Moreover, clinical management of infertility associated with endometriosis can be challenging due to this heterogeneity. Innovative non-invasive diagnostic tools are on the horizon that may allow us to target the specific dysfunctional alteration in the reproduction process. Currently the treatment should be individualized according to the clinical situation and to the suspected level of impairment. Here we review the etiology of endometriosis related infertility as well as current treatment options, including the roles of surgery and assisted reproductive technologies.

Comprehensive analysis of differentially expressed profiles of mRNA, lncRNA, and miRNA of Yili geese ovary at different egg-laying stages

Background

The development of the ovaries is an important factor that affects egg production performance in geese. Ovarian development is regulated by genes that are expressed dynamically and stage-specifically. The transcriptome profile analysis on ovarian tissues of goose at different egg laying stages could provide an important basis for screening and identifying key genes regulating ovarian development.

Results

In this study, 4 ovary tissues at each breeding period of pre-laying (PP), laying (LP), and ceased-laying period (CP), respectively, with significant morphology difference, were used for RNA extraction and mRNAs, lncRNAs, and miRNAs comparison in Yili geese. CeRNA regulatory network was constructed for key genes screening. A total of 337, 1136, and 525 differentially expressed DE mRNAs, 466, 925, and 742 DE lncRNAs and 258, 1131 and 909 DE miRNAs were identified between PP and LP, between CP and LP, and between CP and PP groups, respectively. Functional enrichment analysis showed that the differentially expressed mRNAs and non-coding RNA target genes were mainly involved in the cell process, cytokine-cytokine receptor interaction, phagosome, calcium signaling pathway, steroid biosynthesis and ECM-receptor interaction. Differential genes and non-coding RNAs, PDGFRB, ERBB4, LHCGR, MSTRG.129094.34, MSTRG.3524.1 and gga-miR-145–5p, related to reproduction and ovarian development were highly enriched. Furthermore, lncRNA-miRNA-mRNA regulatory networks related to ovary development were constructed.

Conclusions

Our study found dramatic transcriptomic differences in ovaries of Yili geese at different egg-laying stages, and a differential lncRNA-miRNA-mRNA regulatory network related to cell proliferation, differentiation and apoptosis and involved in stromal follicle development were established and preliminarily validated, which could be regarded as a key regulatory pathway of ovarian development in Yili geese.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08774-4.

Dissecting the miR-451a-Mif Pathway in Endometriosis Pathophysiology Using a Syngeneic Mouse Model: Temporal Expression of Lesion Mif Receptors, Cd74 and Cxcr4

Endometriosis is an enigmatic disease characterized by pain and infertility in which endometrial tissue grows in ectopic locations, predominantly the pelvic cavity. The pathogenesis and pathophysiology of endometriosis is complex and postulated to involve alterations in inflammatory, cell proliferation and post-transcriptional regulatory pathways among others. Our understanding on the pathogenesis and pathophysiology of endometriosis is further complicated by the fact that endometriosis can only be diagnosed by laparoscopy only after the disease has manifested. This makes it difficult to understand the true pathogenesis as a cause-and-effect relationship is difficult to ascertain. To aid in our understanding on endometriosis pathogenesis and pathophysiology, numerous rodent models have been developed. In this case, we discuss further assessment of a miR-451a-macrophage migration inhibitory factor (Mif) pathway which contributes to lesion survival. Specifically, we evaluate the temporal expression of lesion Mif receptors, Cd74 and Cxcr4 using host mice which express wild-type or miR-451a deficient lesions. Similar to that observed in humans and a non-human primate model of endometriosis, Cd74 expression is elevated in lesion tissue in a temporal fashion while that of Cxcr4 shows minimal increase during initial lesion establishment but is reduced later during the lifespan. Absence of miR-451a during initial lesion establishment is associated with an augmentation of Cd74, but no Cxcr4 expression. The data obtained in this study provide further support for a role of Mif receptors, Cd74 and Cxcr4 in the pathophysiology of endometriosis.

Myometrial-derived CXCL12 promotes lipopolysaccharide induced preterm labour by regulating macrophage migration, polarization and function in mice

Preterm birth is a major contributor to neonatal mortality and morbidity. Infection results in elevation of inflammation-related cytokines followed by infiltration of immune cells into gestational tissue. CXCL12 levels are elevated in preterm birth indicating it may have a role in preterm labour (PTL); however, the pathophysiological correlations between CXCL12/CXCR4 signalling and premature labour are poorly understood. In this study, PTL was induced using lipopolysaccharide (LPS) in a murine model. LPS induced CXCL12 RNA and protein levels significantly and specifically in myometrium compared with controls (3-fold and 3.5-fold respectively). Highest levels were found just before the start of labour. LPS also enhanced the infiltration of neutrophils, macrophages and T cells, and induced macrophage M1 polarization. In vitro studies showed that condition medium from LPS-treated primary smooth muscle cells (SMC) induced macrophage migration, M1 polarization and upregulated inflammation-related cytokines such as interleukin (IL)-1, IL-6 and tumor necrosis factor alpha (TNF-α). AMD3100 treatment in pregnant mice led to a significant decrease in the rate of PTL (70%), prolonged pregnancy duration and suppressed macrophage infiltration into gestation tissue by 2.5-fold. Further, in-vitro treatment of SMC by AMD3100 suppressed the macrophage migration, decreased polarization and downregulated IL-1, IL-6 and TNF-α expression. LPS treatment in pregnant mice induced PTL by increasing myometrial CXCL12, which recruits immune cells that in turn produce inflammation-related cytokines. These effects stimulated by LPS were completely reversed by AMD3100 through blocking of CXCL12/CXCR4 signalling. Thus, the CXCL12/CXCR4 axis presents an excellent target for preventing infection and inflammation-related PTL.

CPEB3, an RNA-Binding Protein, Modulates the Behavior of Endometriosis-Derived Stromal Cells via Regulating CXCL12

Endometriosis is a benign gynecological disease sharing several features with malignant tumor. Cytoplasmic polyadenylation element-binding protein 3 (CPEB3), a potential target of miR-21-5p, is downregulated in endometriotic specimens. However, the function of CPEB3 in endometriosis is elusive. In this study, in cultured primary human endometrial stromal cells (ESCs), the overexpression and inhibition of CPEB3 were achieved by transduction of adenovirus-mediated CPEB3 overexpressed plasmid and shRNA, respectively. Functional analysis uncovered that upregulated CPEB3 reduced cell viability and arrested cell cycle entry. The expression of cyclin D1 and c-Myc was decreased after CPEB3 overexpression. Overexpression of CPEB3 facilitated ESC apoptotic potential, accompanied by increased Bax, cleaved-caspase 3 and cleaved-caspase 9, and reduced Bcl2. Moreover, elevated CPEB3 weakened migration and invasion abilities of ESCs. CPEB3 overexpression also reduced the expression of fibronectin and vimentin and the activities of matrix metalloproteinase (MMP)-9 and MMP-2. Interestingly, these effects were counteracted by CPEB3 inhibition. Furthermore, CPEB3 controlled the protein level of CXCL12, a homeostatic chemokine. CXCL12 elevation partially reversed the effects of CPEB3 on inhibiting ESC proliferation, migration and invasion, and promoting apoptosis. Based on these findings, it seems possible that CPEB3, as a critical player, attenuated the progression of endometriosis through repressing CXCL12 expression.

Endometriosis stem cell sources and potential therapeutic targets: literature review and bioinformatics analysis

The stem cell origin theory of endometriosis (EMS) is a significant area of new research but the sources of this have yet to be adequately summarized. Existing treatments for EMS are commonly associated with a high recurrence rate; consequently, there is an urgent need to develop new therapeutic measures for the future treatment of this disease from the view of stem cells and gene therapy. Recently, we described the evidence for the potential sources of EMS stem cells and other key molecules participating in the establishment of lesions, and predict the miRNAs that target these key genes via bioinformatics analysis for further research. This review highlights the origin of EMS stem cells and potential therapy targets.

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

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

Niclosamide suppresses macrophage-induced inflammation in endometriosis†

Endometriosis is a common gynecological disease, which causes chronic pelvic pain and infertility in women of reproductive age. Due to limited efficacy of current treatment options, a critical need exists to develop new and effective treatments for endometriosis. Niclosamide is an efficacious and FDA-approved drug for the treatment of helminthosis in humans that has been used for decades. We have reported that niclosamide reduces growth and progression of endometriosis-like lesions via targeting STAT3 and NFĸB signaling in a mouse model of endometriosis. To examine the effects of niclosamide on macrophage-induced inflammation in endometriosis, a total of 29 stage III-IV endometrioma samples were used to isolate human endometriotic stromal cells (hESCs). M1 or M2 macrophages were isolated and differentiated from fresh human peripheral blood samples. Then, hESCs were cultured in conditioned media (CM) from macrophages with/without niclosamide. Niclosamide dose dependently reduced cell viability and the activity of STAT3 and NFκB signaling in hESCs. While macrophage CM stimulated cell viability in hESCs, niclosamide inhibited this stimulation. Macrophage CM stimulated the secretion of proinflammatory cytokines and chemokines from hESCs. Most of these secreted factors were inhibited by niclosamide. These results indicate that niclosamide is able to reduce macrophage-induced cell viability and cytokine/chemokine secretion in hESCs by inhibiting inflammatory mechanisms via STAT3 and/or NFκB signaling.

Loss of Cxcr4 in Endometriosis Reduces Proliferation and Lesion Number while Increasing Intraepithelial Lymphocyte Infiltration

Hyperactivation of the CXCL12-CXCR4 axis occurs in endometriosis; the therapeutic potential of treatments aimed at global inhibition of the axis was recently reported. Because CXCR4 is predominantly expressed on epithelial cells in the uterus, this study explored the effects of targeted disruption of CXCR4 in endometriosis lesions. Uteri derived from adult female mice homozygous for a floxed allele of CXCR4 and co-expressing Cre recombinase under control of progesterone receptor promoter were sutured onto the peritoneum of cycling host mice expressing the green fluorescent protein. Four weeks after endometriosis induction, significantly lower number of lesions developed in Cxcr4-conditional knockout lesions relative to those in controls (37.5% vs. 68.8%, respectively). In lesions that developed in Cxcr4-knockout, reduced epithelial proliferation was associated with a lower ratio of epithelial to total lesion area compared with controls. Furthermore, while CD3⁺ lymphocytes were largely excluded from the epithelial compartment in control lesions, in Cxcr4-knockout lesions, CD3⁺ lymphocytes infiltrated the Cxcr4-deficient epithelium in the diestrus and proestrus stages. Current data demonstrate that local CXCR4 expression is necessary for proliferation of the epithelial compartment of endometriosis lesions, that its downregulation compromises lesion numbers, and suggest a role for epithelial CXCR4 in lesion immune evasion.

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.

Endometriosis Cell Proliferation Induced by Bone Marrow Mesenchymal Stem Cells

Endometriosis is an estrogen-dependent gynecological disorder that affects 10% of reproductive-aged women and causes pelvic pain and infertility. Bone marrow-derived stem cells (BMDCs) are known to engraft endometriosis in association with lesion growth; however, they do not undergo significant clonal expansion. The indirect effects of BMDCs on endometriosis growth and cell proliferation are not well characterized. Here, we demonstrate that BMDCs' co-culture increased endometrial stromal cell proliferation. In vitro studies using endometrial cells showed that BMDCs increased cell proliferation and activation of CDK1 in both an endometriosis cell line and primary endometrial stromal cells from women with endometriosis, however not in normal endometrial cells. In vivo studies using a mouse model of endometriosis showed increased CDK1+ expression associated with engrafted GFP + BMDCs. These results suggest that endometrial cell proliferation is induced by stem cell-derived trophic factors leading to the growth of endometriotic lesions. Targeting the specific signaling molecules secreted by BMDC may lead to novel therapeutic strategies for controlling cell proliferation in endometriosis.

Endometriosis stromal cells induce bone marrow mesenchymal stem cell differentiation and PD-1 expression through paracrine signaling

Endometriosis is an estrogen-dependent, inflammatory gynecological disorder characterized by the growth of endometrial cells in lesions outside the uterus. Bone marrow-derived cells (BMDCs) engraft lesions and increase lesion size. Do endometriosis cells regulate differentiation of engrafted BMDCs in the pathogenesis and growth of endometriosis? Here, we report endometriosis derived stromal cells promote the differentiation of BMDCs to stromal, epithelial and leukocyte cell fates through paracrine signaling. In-vitro studies demonstrated that both mRNA and protein levels of vimentin, cytokeratin and PD-1 were significantly increased in BMDCs cocultured with stromal cells from endometriosis (ENDO) patients compared to stromal cells from normal endometrium (CNTL). Increased expression of PD-1 has been reported in malignancy where it promotes T cell quiescence and immune tolerance. Increased PD-1 was also confirmed in-vivo where we showed that PD-1 expression was induced in BMDCs engrafted into endometriotic lesions in a murine model of endometriosis. AMD3100, an antagonist for CXCR4 receptor inhibited PD-1 expression in BMDCs suggesting that PD-1 induction requires CXCL12. These results suggest that endometriosis stimulated BMDC differentiation through paracrine signaling and increased T cell PD-1 expression. Increased PD-1 expression may be one mechanism by which endometriosis avoids immune surveillance.

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.

Uterine Stem Cells and Benign Gynecological Disorders: Role in Pathobiology and Therapeutic Implications

Stem cells in the endometrium and myometrium possess an immense regenerative potential which is necessary to maintain the menstrual cycle and support pregnancy. These cells, as well as bone marrow stem cells, have also been implicated in the development of common benign gynecological disorders including leiomyomas, endometriosis and adenomyosis. Current evidence suggests the conversion of uterine stem cells to tumor initiating stem cells in leiomyomas, endometriosis stem cells, and adenomyosis stem cells, acquiring genetic and epigenetic alterations for the progression of each benign condition. In this comprehensive review, we aim to summarize the progress that has been made to characterize the involvement of stem cells in the pathogenesis of benign gynecologic conditions which, despite their enormous burden, are not yet fully understood. We focus on the stem cell characteristics and aberrations that contribute to the development of benign gynecological disorders and the possible clinical implications of what is known so far. Lastly, we discuss the role of uterine stem cells in the setting of regenerative medicine, particularly in the treatment of Asherman syndrome.Graphical abstract.

Menstruation: science and society

Women's health concerns are generally underrepresented in basic and translational research, but reproductive health in particular has been hampered by a lack of understanding of basic uterine and menstrual physiology. Menstrual health is an integral part of overall health because between menarche and menopause, most women menstruate. Yet for tens of millions of women around the world, menstruation regularly and often catastrophically disrupts their physical, mental, and social well-being. Enhancing our understanding of the underlying phenomena involved in menstruation, abnormal uterine bleeding, and other menstruation-related disorders will move us closer to the goal of personalized care. Furthermore, a deeper mechanistic understanding of menstruation-a fast, scarless healing process in healthy individuals-will likely yield insights into a myriad of other diseases involving regulation of vascular function locally and systemically. We also recognize that many women now delay pregnancy and that there is an increasing desire for fertility and uterine preservation. In September 2018, the Gynecologic Health and Disease Branch of the Eunice Kennedy Shriver National Institute of Child Health and Human Development convened a 2-day meeting, "Menstruation: Science and Society" with an aim to "identify gaps and opportunities in menstruation science and to raise awareness of the need for more research in this field." Experts in fields ranging from the evolutionary role of menstruation to basic endometrial biology (including omic analysis of the endometrium, stem cells and tissue engineering of the endometrium, endometrial microbiome, and abnormal uterine bleeding and fibroids) and translational medicine (imaging and sampling modalities, patient-focused analysis of menstrual disorders including abnormal uterine bleeding, smart technologies or applications and mobile health platforms) to societal challenges in health literacy and dissemination frameworks across different economic and cultural landscapes shared current state-of-the-art and future vision, incorporating the patient voice at the launch of the meeting. Here, we provide an enhanced meeting report with extensive up-to-date (as of submission) context, capturing the spectrum from how the basic processes of menstruation commence in response to progesterone withdrawal, through the role of tissue-resident and circulating stem and progenitor cells in monthly regeneration-and current gaps in knowledge on how dysregulation leads to abnormal uterine bleeding and other menstruation-related disorders such as adenomyosis, endometriosis, and fibroids-to the clinical challenges in diagnostics, treatment, and patient and societal education. We conclude with an overview of how the global agenda concerning menstruation, and specifically menstrual health and hygiene, are gaining momentum, ranging from increasing investment in addressing menstruation-related barriers facing girls in schools in low- to middle-income countries to the more recent "menstrual equity" and "period poverty" movements spreading across high-income countries.

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

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

Bioinformatic analysis reveals the importance of epithelial-mesenchymal transition in the development of endometriosis

Background: Endometriosis is a frequently occurring disease in women, which seriously affects their quality of life. However, its etiology and pathogenesis are still unclear. Methods: To identify key genes/pathways involved in the pathogenesis of endometriosis, we recruited 3 raw microarray datasets (GSE11691, GSE7305, and GSE12768) from Gene Expression Omnibus database (GEO), which contain endometriosis tissues and normal endometrial tissues. We then performed in-depth bioinformatic analysis to determine differentially expressed genes (DEGs), followed by gene ontology (GO), Hallmark pathway enrichment and protein-protein interaction (PPI) network analysis. The findings were further validated by immunohistochemistry (IHC) staining in endometrial tissues from endometriosis or control patients. Results: We identified 186 DEGs, of which 118 were up-regulated and 68 were down-regulated. The most enriched DEGs in GO functional analysis were mainly associated with cell adhesion, inflammatory response, and extracellular exosome. We found that epithelial-mesenchymal transition (EMT) ranked first in the Hallmark pathway enrichment. EMT may potentially be induced by inflammatory cytokines such as CXCL12. IHC confirmed the down-regulation of E-cadherin (CDH1) and up-regulation of CXCL12 in endometriosis tissues. Conclusions: Utilizing bioinformatics and patient samples, we provide evidence of EMT in endometriosis. Elucidating the role of EMT will improve the understanding of the molecular mechanisms involved in the development of endometriosis.

Endometriotic inflammatory microenvironment induced by macrophages can be targeted by niclosamide†

Endometriosis causes severe chronic pelvic pain and infertility. We have recently reported that niclosamide treatment reduces growth and progression of endometriosis-like lesions and inflammatory signaling (NF${\rm \small K}$B and STAT3) in a mouse model. In the present study, we examined further inhibitory mechanisms by which niclosamide affects endometriotic lesions using an endometriotic epithelial cell line, 12Z, and macrophages differentiated from a monocytic THP-1 cell line. Niclosamide dose dependently reduced 12Z viability, reduced STAT3 and NF${\rm \small K}$B activity, and increased both cleaved caspase-3 and cleaved PARP. To model the inflammatory microenvironment in endometriotic lesions, we exposed 12Z cells to macrophage conditioned media (CM). Macrophages were differentiated from THP-1 cells using 12-O-tetradecanoylphorbol-13-acetate as M0, and then M0 macrophages were polarized into M1 or M2 using LPS/IFNγ or IL4/IL13, respectively. Conditioned media from M0, M1, or M2 cultures increased 12Z viability. This effect was blocked by niclosamide, and cell viability returned to that of CM from cells treated with niclosamide alone. To assess proteins targeted by niclosamide in 12Z cells, CM from 12Z cells cultured with M0, M1, or M2 with/without niclosamide were analyzed by cytokine/chemokine protein array kits. Conditioned media from M0, M1, and/or M2 stimulated the secretion of cytokines/chemokines from 12Z cells. Production of most of these secreted cytokines/chemokines in 12Z cells was inhibited by niclosamide. Knockdown of each gene in 12Z cells using siRNA resulted in reduced cell viability. These results indicate that niclosamide can inhibit the inflammatory factors in endometriotic epithelial cells stimulated by macrophages by targeting STAT3 and/or NF${\rm \small K}$B signaling.

The Pathogenesis of Adenomyosis vis-à-vis Endometriosis

Adenomyosis is used to be called endometriosis interna, and deep endometriosis is now called adenomyosis externa. Thus, there is a question as to whether adenomyosis is simply endometriosis of the uterus, either from the perspective of pathogenesis or pathophysiology. In this manuscript, a comprehensive review was performed with a literature search using PubMed for all publications in English, related to adenomyosis and endometriosis, from inception to June 20, 2019. In addition, two prevailing theories, i.e., invagination—based on tissue injury and repair (TIAR) hypothesis—and metaplasia, on adenomyosis pathogenesis, are briefly overviewed and then critically scrutinized. Both theories have apparent limitations, i.e., difficulty in falsification, explaining existing data, and making useful predictions. Based on the current understanding of wound healing, a new hypothesis, called endometrial-myometrial interface disruption (EMID), is proposed to account for adenomyosis resulting from iatrogenic trauma to EMI. The EMID hypothesis not only highlights the more salient feature, i.e., hypoxia, at the wounding site, but also incorporates epithelial mesenchymal transition, recruitment of bone-marrow-derived stem cells, and enhanced survival and dissemination of endometrial cells dispersed and displaced due to iatrogenic procedures. More importantly, the EMID hypothesis predicts that the risk of adenomyosis can be reduced if certain perioperative interventions are performed. Consequently, from a pathogenic standpoint, adenomyosis is not simply endometriosis of the uterus, and, as such, may call for interventional procedures that are somewhat different from those for endometriosis to achieve the best results.

CXCL12 Attracts Bone Marrow-Derived Cells to Uterine Leiomyomas

Uterine leiomyomas, also known as fibroids or myomas, are a common benign gynecologic tumor found in women of reproductive age. Though advances have been made in understanding leiomyomas, the etiology and pathogenesis of this disease are not fully characterized. Current evidence supports a role of putative human uterine stem/progenitor cells in the onset of uterine disease such as uterine myomas. In this study, we report that increased expression of CXCL12 in leiomyomas recruits bone marrow-derived cells (BMDCs) that may contribute to leiomyoma growth. Tissue was collected from leiomyomas or control myometrium from women with or without leiomyomas. qRT-PCR analysis showed increased expression of CXCL12 and decreased CXCR4 expression in the leiomyoma and myometrium of women with leiomyoma compared with normal myometrium. Increased CXCL12 protein secretion from cultured myoma cells was confirmed by ELISA. Further, we found that BMDCs migration was increased toward leiomyoma conditioned medium compared with conditioned medium from normal myometrium. CXCR4 antagonist AMD3100 completely blocked this migration. Engraftment of BMDCs significantly increased in myoma of mouse uteri treated with CXCL12 compared with placebo. We conclude that CXCL12 may play a role in leiomyomas growth by attracting bone marrow-derived cells to leiomyoma. Therefore, CXCL12 and its receptors are novel targets for leiomyoma therapy.

CXCR4 or CXCR7 antagonists treat endometriosis by reducing bone marrow cell trafficking

Adult stem cells have a major role in endometrial physiology, including remodelling and repair. However, they also have a critical role in the development and progression of endometriosis. Bone marrow-derived stem cells engraft eutopic endometrium and endometriotic lesions, differentiating to both stromal and epithelial cell fates. Using a mouse bone marrow transplantation model, we show that bone marrow-derived cells engrafting endometriosis express CXCR4 and CXCR7. Targeting either receptor by the administration of small molecule receptor antagonists AMD3100 or CCX771, respectively, reduced BM-derived stem cell recruitment into endometriosis implants. Endometriosis lesion size was decreased compared to vehicle controls after treatment with each antagonist in both an early growth and established lesion treatment model. Endometriosis lesion size was not effected when the local effects of CXCL12 were abrogated using uterine-specific CXCL12 null mice, suggesting an effect primarily on bone marrow cell migration rather than a direct endometrial effect. Antagonist treatment also decreased hallmarks of endometriosis physiopathology such as pro-inflammatory cytokine production and vascularization. CXCR4 and CXCR7 antagonists are potential novel, non-hormonal therapies for endometriosis.

The Origin and Pathogenesis of Endometriosis

Recent molecular genetic findings on endometriosis and normal endometrium suggest a modified model in which circulating epithelial progenitor or stem cells intended to regenerate uterine endometrium after menstruation may become overreactive and trapped outside the uterus. These trapped epithelium-committed progenitor cells form nascent glands through clonal expansion and recruit polyclonal stromal cells, leading to the establishment of deep infiltrating endometriosis. Once formed, the ectopic tissue becomes subject to immune surveillance, resulting in chronic inflammation. The inflammatory response orchestrated by nuclear factor-κB signaling is exacerbated by aberrations in the estrogen receptor-β and progesterone receptor pathways, which are also affected by local inflammation, forming a dysregulated inflammation-hormonal loop. Glandular epithelium within endometriotic tissue harbors cancer-associated mutations that are frequently detected in endometriosis-related ovarian cancers. In this review, we summarize recent advances that have illuminated the origin and pathogenesis of endometriosis and have provided new avenues for research that promise to improve the early diagnosis and management of endometriosis.

Pharmacological blockage of the CXCR4-CXCL12 axis in endometriosis leads to contrasting effects in proliferation, migration, and invasion

High levels of inflammatory factors including chemokines have been reported in peritoneal fluid and blood of women with endometriosis. CXCL12 mediates its action by interaction with its specific receptor, CXCR4, reported to be elevated in human endometriosis lesions and in the rat model of endometriosis. Activation of the CXCR4-CXCL12 axis increases cell proliferation, migration, and invasion of cancer cells. To obtain insights into the CXCR4 expression profile in lesions and endometrium, as well as functionality of the CXCR4-CXCL12 axis in endometriosis, we analyzed the expression of CXCR4 in tissues on a human tissue array and studied CXCL12-mediated activation of proliferation, invasion, and migration in vitro. We observed differences in levels of nuclear CXCR4 expression among lesion types, being higher in ovarian lesions. Endometriotic cell lines (12Z) showed higher levels of CXCR4, proliferative and migratory potential, and AKT phosphorylation/kinase activity compared to untreated control cells (endometrial epithelial cells). CXCL12 and endometriotic stromal cell-enriched media increased proliferation of non-endometriotic epithelial cells. CXCL12 caused a significant increase in 12Z cell invasion but had no effect on migration; AMD3100, a CXCR4-specific inhibitor, significantly increased invasion of 12Z cells but decreased their migration. However, treatment with CXCL12 plus AMD3100 significantly decreased invasion and migration of 12Z cells. In conclusion, the CXCR4-CXCL12 axis is functional in endometriosis cells, but the expression of CXCR4 varies among lesions. CXCL12 promoted proliferation, migration, and invasion of endometriotic cells, while inducing AKT phosphorylation and activity, but pharmacologically blocking this axis in the absence of the ligand induced their invasiveness.

Uterine stem cells: from basic research to advanced cell therapies

BACKGROUND

Stem cell research in the endometrium and myometrium from animal models and humans has led to the identification of endometrial/myometrial stem cells and their niches. This basic knowledge is beginning to be translated to clinical use for incurable uterine pathologies. Additionally, the implication of bone marrow-derived stem cells (BMDSCs) in uterine physiology has opened the field for the exploration of an exogenous and autologous source of stem cells.

OBJECTIVE AND RATIONALE

In this review, we outline the progress of endometrial and myometrial stem/progenitor cells in both human and mouse models from their characterization to their clinical application, indicating roles in Asherman syndrome, atrophic endometrium and tissue engineering, among others.

SEARCH METHODS

A comprehensive search of PubMed and Google Scholar up to December 2017 was conducted to identify peer-reviewed literature related to the contribution of bone marrow, endometrial and myometrial stem cells to potential physiological regeneration as well as their implications in pathologies of the human uterus.

OUTCOMES

The discovery and main characteristics of stem cells in the murine and human endometrium and myometrium are presented together with the relevance of their niches and cross-regulation. The current state of advanced stem cell therapy using BMDSCs in the treatment of Asherman syndrome and atrophic endometrium is analyzed. In the myometrium, the understanding of genetic and epigenetic defects that result in the development of tumor-initiating cells in the myometrial stem niche and thus contribute to the growth of uterine leiomyoma is also presented. Finally, recent advances in tissue engineering based on the creation of novel three-dimensional scaffolds or decellularisation open up new perspectives for the field of uterine transplantation.

WIDER IMPLICATIONS

More than a decade after their discovery, the knowledge of uterine stem cells and their niches is crystalising into novel therapeutic approaches aiming to treat with cells those conditions that cannot be cured with drugs, particularly the currently incurable uterine pathologies. Additional work and improvements are needed, but the basis has been formed for this therapeutic application of uterine cells.

Efficient Production of Murine Uterine Damage Model

BACKGROUND

Thin or damaged endometrium causes uterine factor-derived infertility resulting in a failure of embryonic implantation. Regeneration of endometrium is a major issue in gynecology and reproductive medicine. Various types of cells and scaffolds were studied to establish an effective therapeutic strategy. For this type of investigations, production of optimal animal models is indispensable. In this study, we tried to establish various murine uterine damage models and compared their features.

METHODS

Three to ten-week-old C57BL/6 female mice were anesthetized using isoflurane. Chemical and mechanical methods using ethanol (EtOH) at 70 or 100% and copper scraper were compared to determine the most efficient condition. Damage of uterine tissue was induced either by vaginal or dorsal surgical approach. After 7-10 days, gross and microscopic morphology, safety and efficiency were compared among the groups.

RESULTS

Both chemical and mechanical methods resulted in thinner endometrium and reduced number of glands. Gross morphology assessment revealed that the damaged regions of uteri showed various shapes including shrinkage or cystic dilatation of uterine horns. The duration of anesthesia significantly affected recovery after procedure. Uterine damage was most effectively induced by dorsal approach using 100% EtOH treatment compared to mechanical methods.

CONCLUSION

Taken together, murine uterine damage models were most successfully established by chemical treatment. This production protocols could be applied further to larger animals such as non-human primate.

Therapeutic strategies involving uterine stem cells in reproductive medicine

PURPOSE OF REVIEW

The current review provides an update on recent advances in stem cell biology relevant to female reproduction.

RECENT FINDINGS

Stem cells are undifferentiated cells that often serve as a reservoir of cells to regenerate tissue in settings or injury or cell loss. The endometrium has progenitor stem cells that can replace all of the endometrium during each menstrual cycle. In addition, multipotent endometrial cells replace these progenitor cells when depleted. Recruitment of stem cells from outside of the uterus occurs in setting of increased demand such as ischemia or injury. Bone marrow-derived multipotent stem cells are recruited to the uterus by estrogen or injury-induced expression of the chemokine CXCL12. In the setting of overwhelming injury, especially in the setting of low estrogen levels, there may be insufficient stem cell recruitment to adequately repair the uterus resulting in conditions such as Asherman syndrome or other endometrial defects. In contrast, excessive recruitment of stem cells underlies endometriosis. Enhanced understanding of stem-cell mobilization, recruitment, and engraftment has created the possibility of improved therapy for endometrial defects and endometriosis through enhanced manipulation of stem-cell trafficking. Further, the normal endometrium is a rich source of multipotent stem cells that can be used for numerous applications in regenerative medicine beyond reproduction.

SUMMARY

A better understanding of reproductive stem-cell biology may allow improved treatment of endometrial disease such as Asherman syndrome and other endometrial receptivity defects. Inhibiting stem-cell mobilization may also be helpful in endometriosis therapy. Finally, endometrial derived multipotent stem cells may play a crucial role in cell therapy for regenerative medicine.

Pathogenesis of endometriosis: the genetic/epigenetic theory

OBJECTIVE

To study the pathophysiology of endometriosis.

DESIGN

Overview of observations on endometriosis.

SETTING

Not applicable.

PATIENT(S)

None.

INTERVENTIONS(S)

None.

MAIN OUTCOME MEASURE(S)

The hypothesis is compatible with all observations.

RESULT(S)

Endometriosis, endometrium-like tissue outside the uterus, has a variable macroscopic appearance and a poorly understood natural history. It is a hereditary and heterogeneous disease with many biochemical changes in the lesions, which are clonal in origin. It is associated with pain, infertility, adenomyosis, and changes in the junctional zone, placentation, immunology, plasma, peritoneal fluid, and chronic inflammation of the peritoneal cavity. The Sampson hypothesis of implanted endometrial cells following retrograde menstruation, angiogenic spread, lymphogenic spread, or the metaplasia theory cannot explain all observations if metaplasia is defined as cells with reversible changes and an abnormal behavior/morphology due to the abnormal environment. We propose a polygenetic/polyepigenetic mechanism. The set of genetic and epigenetic incidents transmitted at birth could explain the hereditary aspects, the predisposition, and the endometriosis-associated changes in the endometrium, immunology, and placentation. To develop typical, cystic ovarian or deep endometriosis lesions, a variable series of additional transmissible genetic and epigenetic incidents are required to occur in a cell which may vary from endometrial to stem cells. Subtle lesions are viewed as endometrium in a different environment until additional incidents occur. Typical cystic ovarian or deep endometriosis lesions are heterogeneous and represent three different diseases.

CONCLUSION(S)

The genetic epigenetic theory is compatible with all observations on endometriosis. Implications for treatment and prevention are discussed.

Distinct developmental trajectories of endometriotic epithelium and stroma: implications for the origins of endometriosis

Endometriosis is a common gynecological disease characterized by the ectopic growth of endometrium-like tissue. Despite the widespread prevalence of endometriosis, its pathogenesis remains poorly understood. A recent study by Noë et al provides evidence that the epithelium and stroma within the same endometriotic lesions follow distinct and independent developmental trajectories. They used droplet digital polymerase chain reaction analysis of laser-captured epithelium-enriched and stroma-enriched endometriosis tissue, and found that all 19 somatic passenger mutations analyzed were enriched exclusively in the epithelial compartment. These findings are consistent with the clonal expansion of epithelial cells, whereas stromal cells may be continuously regenerated or recruited over the course of disease. Further findings of differing allelic frequencies among passenger mutations within the epithelium of the same endometriotic lesions are suggestive of subclonality or the existence of multiple clones in some cases. Overall, the authors' observations of clonally dominant somatic passenger mutations in the epithelium and not the stroma of endometriosis add to the recent description of cancer-associated mutations in such lesions, and provide clues to the pathogenesis of endometriosis. Further studies to determine where and when these mutations occur and whether they can be used to develop the first biologically informed classification system for endometriosis are warranted. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

CXCL12 induces migration of Schwann cells via p38 MAPK and autocrine of CXCL12 by the CXCR4 receptor

Schwann cells (SCs) play a crucially supportive role in repair of injured peripheral nerve system (PNS). CXCL12 plays a significant role in migration of stem cells and embryonic developmental cells and CXCL12 is strongly chemotactic for a variety of cells. Our study was designed to determine the role of CXCL12 in Schwann cell proliferation and migration. Our study demonstrated that CXCL12 had no effect on Schwann cell proliferation while significantly promoting Schwann cell migration. CXCL12-induced Schwann cell migration was significantly attenuated by inhibition of its receptor CXCR4 and p38 MAPK through co-treatment with AMD3100 and SB203580, separately. Besides, Western blot, QRT-PCR, and ELISA indicated that treatment with CXCL12 enhanced expression of CXCL12 by Schwann cells. In conclusion, CXCL12-enhanced SCs migration is mediated by secreting CXCL12 and p38 MAPK via receptor CXCR4, suggesting that CXCL12 has potential application value for PNS regeneration and could serve as a new therapeutic strategy in peripheral nerve diseases.

Independent development of endometrial epithelium and stroma within the same endometriosis

The pathogenesis of endometriosis, a common benign but debilitating disease in women, remains elusive. The currently held stem cell theory posits that circulating progenitor/stem cells are deposited outside the uterus, where they differentiate into endometrial stroma and glandular tissue to establish endometriosis. Fundamental to testing this hypothesis is to elucidate the evolution of both tissue types. Here, we applied droplet digital PCR to analyze synonymous and missense somatic passenger mutations, which are neutral with respect to clonal selection, among six non-superficial endometriotic lesions. We found that among 19 mutations sequenced, all were significantly enriched in epithelial but not in stromal components of every lesion examined. Our data indicate that the evolution of non-superficial endometriosis is complex, in that epithelium is clonal and its development is independent of stroma, providing new insight into the genesis of endometriosis. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

G-Protein-Coupled Receptor CXCR7 Is Overexpressed in Human and Murine Endometriosis

Endometriosis is a chronic inflammatory disease. Dysfunctional regulation of chemokines and chemokine receptors is a crucial aspect of endometriosis pathogenesis. Chemokine G-protein-coupled receptors (GPCRs) are important drug targets that regulate inflammation and immunity. Recently, CXCR7, a C-X-C motif containing GPCR, has been identified as a receptor for chemokine ligand CXCL12, one of the best characterized chemokines for cell trafficking, angiogenesis, and cell proliferation in cancer and inflammation. Here, we investigated the expression and localization of CXCR7 in human endometriosis and a murine model of the disease. Normal endometrial epithelium and stroma showed undetectable or very low expression of CXCR7, without any significant changes across phases of the menstrual cycle in humans. CXCR7 is significantly upregulated in endometriosis, showing higher staining in glands and in associated vessels. The mouse model recapitulated the human findings. In conclusion, overexpression of CXCR7 in different cellular populations of endometriosis microenvironment may play a role in the pathogenesis and represent a novel target for treatment.

Cigarette Smoking Affects Uterine Receptivity Markers

OBJECTIVE

Smoking negatively affects fertility and the rate of other endometrial diseases. To determine the effect of smoking on endometrial physiology, we evaluated 2 endometrial regulatory cytokines and receptivity markers, C-X-C motif chemokine ligand 12 (CXCL12) and fibroblast growth factor 2 (FGF2), both in vitro and in vivo.

STUDY DESIGN

The human endometrial stromal cell line (HESC) and primary human endometrial stromal cells were treated with cigarette smoking extract (CSE) or with vehicle control. Twenty female mice were randomly assigned to either cigarette smoke (CS) exposure for 8 weeks or to a nonsmoke (NS) group that received room air. Immunohistochemical analysis of CXCL12 and FGF2 expression was performed in mouse uterine tissue. Human endometrial samples were obtained from both nonsmokers and smokers. Real-time reverse transcription-polymerase chain reaction was performed for all cell cultures and human samples.

RESULTS

Compared to controls, CXCL12 and FGF2 mRNA expression were significantly decreased in CSE-exposed HESC and primary cells. In mice, immunohistochemical analysis showed that both CXCL12 and FGF2 protein expression was lower in the CS group compared to controls. Similarly, both CXCL12 and FGF2 expression were decreased in women who smoke compared to nonsmokers.

CONCLUSION

Decreased endometrial CXCL12 and FGF2 expression contribute to the impaired endometrial receptivity in women who smoke. Smoking is also associated with decreased rates of endometrial cancer and endometriosis; increased CXCL12 and FGF2 are implicated in both conditions. The changes in the expression of cytokines described here may explain the impact of smoking on all of these diseases. Tobacco has direct effects on normal endometrium that impacts endometrial health and disease.