P-selectin as a potential therapeutic target for endometriosis

Potential Mechanisms of Guizhi Fuling Wan in Treating Endometriosis: An Analysis Based on TCMSP and DisGeNET Databases

ETHNOPHARMACOLOGICAL RELEVANCE

Guizhi Fuling Wan (GFW), is a traditional Chinese herbal formula that consists of Cinnamomi Ramulus (Guizhi), Poria Cocos(Schw.) Wolf. (Fuling), Persicae Semen (Taoren), Radix Paeoniae Rubra (Chishao), and Cortex Moutan (Mudanpi). This formula has been used in traditional Chinese medicine for more than 1800 years to treat disorders caused by stagnation of circulation and qi (air).

AIM OF THE STUDY

Based on pre-clinical and clinical studies, this review aimed to reveal the potential mechanisms of GFW in inhibiting endometriosis. The enhancement of therapeutic effects of western medications on endometriosis by GFW was also shown.

MATERIALS AND METHODS

A bibliographic assessment of publications on "Guizhi Fuling Wan" and "endometriosis" indexed in PubMed, Science Direct, and China National Knowledge Infrastructure (CNKI) was conducted. Five pre-clinical studies and 13 clinical studies were selected for this review. Moreover, the targeted molecules of each herb were first extracted from the Traditional Chinese Medicine Systems Pharmacology (TCMSP) Database and Analysis Platform followed by obtaining the endometriosis-related genes from DisGeNET. Subsequently, pathway and gene ontology analyses using David Bioinformatics Resources explored the potential mechanisms of therapeutic effects of GFW in treating endometriosis.

RESULTS

Pre-clinical and clinical studies showed that GFW might inhibit the growth of endometriotic lesion through the modulation of immunity, apoptosis-regulating molecules, and angiogenesis-associated factors, while enhancing the therapeutic effects of western medications in treating endometriosis. Furthermore, pathway and gene ontology analyses demonstrated that GFW might attenuate the disease primarily by affecting AGE-RAGE signaling pathway in diabetic complications (hsa04933) as well as pathways involved in Kaposi sarcoma-associated herpesvirus infection (hsa05167), human cytomegalovirus infection (has05163), and fluid shear stress and atherosclerosis (hsa05418). These pathways were all involved in the regulation of inflammation, angiogenesis, and apoptosis and commonly affected by all herbs.

CONCLUSIONS

The current review revealed that endometriosis is highly associated with aberrant inflammatory, angiogenic, and apoptotic activities. The therapeutic effects of GFW on endometriosis are likely to act through regulating these activities.

Therapeutic roles of platelet-rich plasma to restore female reproductive and endocrine dysfunction

Millions of women worldwide are infertile due to gynecological disorders, including premature ovarian insufficiency, polycystic ovary syndrome, Asherman syndrome, endometrial atrophy, and fallopian tube obstruction. These conditions frequently lead to infertility and have a substantial impact on the quality of life of the affected couples, primarily because of their psychological implications and high financial costs. Recently, using platelets to stimulate cell proliferation and tissue differentiation has emerged as a promising approach in regenerative medicine. Platelet-rich plasma (PRP) shows considerable potential for promoting endometrial hypertrophy and follicle development, making it a promising therapeutic option for tissue repair or replacement. This review provides an overview of the recent advancements and underlying mechanisms of PRP therapy for various female reproductive diseases and presents new therapeutic options for addressing female infertility.

Role of tenascin C in lesion formation in early peritoneal endometriosis

OBJECTIVE

To identify cytokines or extracellular matrix components that contribute to adhesion to, and invasion of, the peritoneum, proximal to lesions in the early phase of endometriosis.

DESIGN

Laboratory-based study.

SETTING

University Hospital and Laboratory of Animal Science.

PATIENTS AND ANIMALS

Five women with ovarian endometrioma, 138 wild-type (WT) C57BL/6N mice, and 48 Tenascin C (Tnc) knockout (TncKO) mice.

INTERVENTIONS

To establish a murine endometriosis model, 20 pieces of minced uterine tissue fragments from each horn were administered intraperitoneally to syngeneic mice. Three days later, endometriotic lesions and peritoneal tissues were collected. Separately, we transfected human peritoneal mesothelial cells (HMrSV5) or human endometrial stromal cells (hESCs) with Tnc small interfering ribonucleic acid.

MAIN OUTCOME MEASURES

We employed a polymerase chain reaction array to profile gene expression in the murine peritoneum, in both peritoneum distal to lesions and peritoneum surrounding lesions (PSL). The expression of upregulated genes in the PSL was verified in the peritoneal samples by real-time reverse transcription-polymerase chain reaction. TncKO mice were used to investigate the role of Tnc in the development of endometriosis. We evaluated the proliferative activity or inflammatory state of lesions by Ki67 or CD3 immunostaining. Intraperitoneal distribution of macrophages was assessed by fluorescence-activated cell sorting. Using Tnc small interfering ribonucleic acid, we examined the invasive capacity of hESCs in a coculture system with HMrSV5.

RESULTS

Tnc gene expression was significantly higher in PSL than in peritoneum distal to lesions. The weight and number of TncKO lesions in TncKO hosts were lower than those of WT lesions in WT hosts. In contrast, the weight and number of nonattached TncKO lesions in TncKO hosts were higher than those of nonattached WT lesions in WT hosts. We observed decreased Ki67-positive cells or H-scores for CD3, a lower proportion of M1 macrophages, and a higher proportion of M2 macrophages in TncKO lesions in TncKO recipients. Silencing of Tnc expression in hESCs and HMrSV5 diminished the invasivity of hESCs.

CONCLUSION

Tnc may be a crucial factor in the development of early peritoneal endometriosis.

Impact of Continuous Estroprogestin Treatment on Circulating Microparticle Levels in Deep Endometriosis Patients

There has been increasing interest in the study of new pathogenic mechanisms in endometriosis (END), including the coagulation/fibrinolysis system and its link with inflammation and tissue remodeling. It has been suggested that END patients, especially with deep-infiltrating (DE) forms, could present a hypercoagulable state revealing higher levels of proinflammatory and procoagulant markers, such as total circulating microparticles (cMPs) and cMP-TF (tissue factor), released by cells in response to damage, activation, or apoptosis. However, no previous study has assessed the effect of END hormonal treatments on cMP and cMP-TF levels. Therefore, the aim of this study was to evaluate the impact of these treatments on cMP and cMP-TF levels in DE patients. Three groups were compared: DE patients receiving a continuous combined oral contraceptive regimen (CCOCR) (n = 41), DE patients without CCOCR (n = 45), and a control group (n = 43). cMP and cMP-TF levels were evaluated in platelet-free plasma. A significant decrease in the total cMP levels was found in the DE group with CCOCR versus the group without CCOCR, reflecting a higher chronic inflammatory status in DE patients that decreased with the treatment. cMP-TF levels were higher in DE patients receiving CCOCR versus those not receiving CCOCR, suggesting that treatments containing estrogens play a predominant role in suppressing the inhibitory pathway of TF.

Anxiety-related behaviors without observation of generalized pain in a mouse model of endometriosis

Endometriosis is a chronic, hormone-dependent, inflammatory disease, characterized by the presence and growth of endometrial tissue outside the uterine cavity. It is associated with moderate to severe pelvic and abdominal pain symptoms, subfertility and a marked reduction in health-related quality of life. Furthermore, relevant co-morbidities with affective disorders like depression or anxiety have been described. These conditions have a worsening effect on pain perception in patients and might explain the negative impact on quality of life observed in those suffering from endometriosis-associated pain. Whereas several studies using rodent models of endometriosis focused on biological and histopathological similarities with the human situation, the behavioral characterization of these models was never performed. This study investigated the anxiety-related behaviors in a syngeneic model of endometriosis. Using elevated plus maze and the novel environment induced feeding suppression assays we observed the presence of anxiety-related behaviors in endometriosis-induced mice. In contrast, locomotion or generalized pain did not differ between groups. These results indicate that the presence of endometriosis lesions in the abdominal cavity could, similarly to patients, induce profound psychopathological changes/impairments in mice. These readouts might provide additional tools for preclinical identification of mechanisms relevant for development of endometriosis-related symptoms.

The Role of Platelets in the Pathogenesis and Pathophysiology of Adenomyosis

Widely viewed as an enigmatic disease, adenomyosis is a common gynecological disease with bewildering pathogenesis and pathophysiology. One defining hallmark of adenomyotic lesions is cyclic bleeding as in eutopic endometrium, yet bleeding is a quintessential trademark of tissue injury, which is invariably followed by tissue repair. Consequently, adenomyotic lesions resemble wounds. Following each bleeding episode, adenomyotic lesions undergo tissue repair, and, as such, platelets are the first responder that heralds the subsequent tissue repair. This repeated tissue injury and repair (ReTIAR) would elicit several key molecular events crucial for lesional progression, eventually leading to lesional fibrosis. Platelets interact with adenomyotic cells and actively participate in these events, promoting the lesional progression and fibrogenesis. Lesional fibrosis may also be propagated into their neighboring endometrial-myometrial interface and then to eutopic endometrium, impairing endometrial repair and causing heavy menstrual bleeding. Moreover, lesional progression may result in hyperinnervation and an enlarged uterus. In this review, the role of platelets in the pathogenesis, progression, and pathophysiology is reviewed, along with the therapeutic implication. In addition, I shall demonstrate how the notion of ReTIAR provides a much needed framework to tether to and piece together many seemingly unrelated findings and how it helps to make useful predictions.

Endometriosis: Cellular and Molecular Mechanisms Leading to Fibrosis

Endometriosis is a chronic inflammatory condition affecting women of reproductive age. A relevant feature of endometriosis is the presence of fibrotic tissue inside and around the lesions, thus contributing to the classic endometriosis-related symptoms, pain, and infertility. The molecular mechanisms responsible for the development of fibrosis in endometriosis are not yet defined. The present review aimed to examine the biological mechanisms and signalling pathways involved in fibrogenesis of endometriotic lesions, highlighting the difference between deep infiltrating and ovarian endometriosis. The main cell types involved in the development of fibrosis are platelets, myofibroblasts, macrophages, and sensory nerve fibers. Members of the transforming growth factor (TGF) -β family, as well as the receptor Notch, or the bioactive sphingolipid sphingosine 1-phosphate (S1P), play a role in the development of tissue fibrosis, resulting in their metabolism and/or their signalling pathways altered in endometriotic lesions. It is relevant the knowledge of the molecular mechanisms that guide and support fibrosis in endometriosis, to identify new drug targets and provide new therapeutic approaches to patients.

Tetramethylpyrazine Retards the Progression and Fibrogenesis of Endometriosis

The development of more efficacious, non-hormonal therapeutics for endometriosis is still an unmet medical need begging to be fulfilled. Growing evidence indicates that endometriotic lesions are wounds undergoing repeated tissue injury and repair, and, as such, platelets play an important role in lesional progression. Tetramethylpyrazine (TMP), a compound derived from a herb that has been used for thousands of years to combat “blood stasis” in traditional Chinese medicine, is a prescription drug in China for the treatment of cerebrovascular disorders. We tested the hypothesis that TMP can decelerate lesional progression through arresting epithelial-mesenchymal transition (EMT), fibroblast-to-myofibroblast transdifferentiation (FMT), and fibrogenesis. We found in our in vitro experiments that TMP treatment suppresses platelet-induced EMT, FMT, cellular contractility, and collagen production in a concentration-dependent manner. We also showed that in a mouse model of endometriosis, treatment with TMP significantly reduced lesion weight and the extent of lesional fibrosis and improved hyperalgesia, mostly likely through the reduction of lesional aggregation of platelets and the lesional expression of markers of EMT, FMT, and fibrogenesis. In light of our results and in view of its excellent safety profiles, TMP appears to be a promising drug candidate for treating endometriosis.

Clinical characteristics, treatment status and complications in women with tube ovarian abscess and endometriosis: a retrospective study

Background

The aim of our present study was to investigate the clinical characteristics, treatment status and complications in women with endometriosis (EM) and tube ovarian abscess (TOA) to determine the possible association between TOA and EM.

Methods

Medical records were used to analyze the clinical characteristics, treatment and complications. Twenty women who were diagnosed with TOA with EM were compared with 93 women diagnosed as having TOA without EM between January, 2008 and December, 2018.

Results

In this study, TOA patients with EM were significantly more likely to have a lower age range (20–39 years) than the non-EM group [11/20 (55.0%) vs 27/93 (29.0%)]. In addition, TOA patients with EM were associated with a significantly lower rate of parity [11/20 (55.0%) vs 75/93 (80.6%)], higher rates of infertility [8/20(40%) vs 0/93(0%)] and a significantly lower incidence of elevated blood platelet counts [5/20 (25%) vs 43/93 (46.2%)]. Furthermore, women with EM had greater blood loss (347 ± 445.77 vs 204.67 ± 289.46) and an increased complication rate [3/20(15%) vs 0/93(0%)]. Among the 3 patients who had complications in the EM group, 2 patients had septic shock and 1 patient had intestinal obstruction. And 1 case who had septic shock followed by IVF treatment. There was no significance difference on other factors.

Conclusions

The present study indicated that EM did not increase the difficulty and time of treatment in patients with TOA, but increased bleeding during surgery and serious complications. It is suggested that doctors should pay more attention to postoperative treatment and nursing in women with TOA and EM, especially those who have a history of recent infertility treatment and related procedures.

Supplementary information

Supplementary information accompanies this paper at 10.1186/s12905-020-01119-x.

Is There a Genetic Predisposition to Postoperative Adhesion Development?

Adhesions are permanent fibrovascular bands between peritoneal surfaces, which develop following virtually all body cavity surgeries. The susceptibility to develop, and the severity, of adhesions following intra-abdominal surgery varies within and between individuals, suggesting that heritable factors influence adhesion development. In this manuscript, we discuss the pathophysiology of adhesion development from the perspective of genetic susceptibility. We restrict our discussion to genes and single-nucleotide polymorphisms (SNPs) that are specifically involved in, or that cause modification of, the adhesion development process. We performed a literature search using the PubMed database for all relevant English language articles up to March 2020 (n = 186). We identified and carefully reviewed all relevant articles addressing genetic mutations or single-nucleotide polymorphisms (SNPs) that impact the risk for adhesion development. We also reviewed references from these articles for additional information. We found several reported SNPs, genetic mutations, and upregulation of messenger RNAs that directly or indirectly increase the propensity for postoperative adhesion development, namely in genes for transforming growth factor beta, vascular endothelial growth factor, interferon-gamma, matrix metalloproteinase, plasminogen activator inhibitor-1, and the interleukins. An understanding of genetic variants could provide insight into the pathophysiology of adhesion development. The information presented in this review contributes to a greater understanding of adhesion development at the genetic level and may allow modification of these genetic risks, which may subsequently guide management in preventing and treating this challenging complication of abdominal surgery. In particular, the information could help identify patients at greater risk for adhesion development, which would make them candidates for anti-adhesion prophylaxis. Currently, agents to reduce postoperative adhesion development exist, and in the future, development of agents, which specifically target individual genetic profile, would be more specific in preventing intraperitoneal adhesion development.

Assessment of Coagulation Parameters in Women Affected by Endometriosis: Validation Study and Systematic Review of the Literature

The presence of endometriosis determines an inflammatory response locally. The objective of this validation study and systematic review was to assess systemic levels of coagulation and inflammatory parameters in women with or without the disease. We conducted a retrospective analysis of a database prospectively collected from January 2017 to February 2020 including n = 572 women who underwent laparoscopic surgery for endometriosis (cases, n = 324) or other benign gynecologic diseases (controls, n = 248). Inflammatory markers and coagulation parameters were determined. An advanced systematic search of the literature on the same parameters was conducted up to April 2020. A significantly higher neutrophil count was found in endometriosis patients. Patients with endometriomas and stage III–IV disease had a significantly lower absolute lymphocyte count and shortened activated partial thromboplastin time (aPTT) values. In the final regression model, aPTT retained significant predictive value for stage III–IV endometriosis (odds ratio (OR) = 0.002, 95% confidence interval (CI) = 0.00–0.445; p = 0.024). Results from the n = 14 included studies in the systematic review are characterized by a high variability, but some consistency has been found for alterations in thrombin time, platelet-to-lymphocyte ratio, and neutrophil count associated with endometriosis. Modest systemic changes of some inflammatory and coagulation parameters are associated with endometriosis. Indeed, all the modifications detected are still within the normal reference intervals, explaining the high heterogeneity among studies.

Enriched Environment Decelerates the Development of Endometriosis in Mouse

We tested the hypothesis that enriched environment (EE), consisting of enlarged space, and increased physical activity and social interactions, hinders the development of endometriosis through attenuated adrenergic signaling, enhanced autophagy, and reduced leptin levels. Two mouse experiments were performed. In Experiment 1, 40 female Balb/C mice were randomly divided into four equal-sized groups, the SE (standard environment), EE, p-EE (EE instituted after endometriosis induction), and the d-EE (SE housing but received uterine fragments from EE donors) groups. Housing intervention was initiated 3 weeks before the induction of endometriosis and continued for 3 weeks after induction. In Experiment 2, 20 female mice were randomly divided into SE and EE groups, and the plasma leptin levels were measured. We measured lesion weight and hotplate latency and performed Masson trichrome staining as well as immunohistochemistry analysis of β2 adrenergic receptor (ADRB2), dopamine receptor D2 (DRD2), vascular endothelial growth factor (VEGF), and microtubule-associated protein light chain 3 (LC3). We found that EE reduced the lesion weight by 40.8% as compared with SE mice, but the reduction in p-EE and d-EE mice did not reach statistical significance. EE significantly reduced staining levels of ADRB2 and VEGF as well as the extent of lesional fibrosis but increased staining levels of LC3 and DRD2 in lesions as compared with the SE group. EE mice had reduced plasma leptin levels as compared with SE mice. Thus, EE decelerates the development of endometriosis and fibrogenesis and improved generalized hyperalgesia, possibly through increased DRD2 expression but decreased expression of ADRB2 and VEGF as well as enhanced autophagy and reduced leptin level.

Is there a correlation between inflammatory markers and coagulation parameters in women with advanced ovarian endometriosis?

Background

Endometriosis is defined as a chronic inflammatory disease. Recent studies have shown that increased coagulation parameters including fibrinogen and platelets are associated with endometriosis. The objective of this study was to determine the levels of inflammatory markers and coagulation parameters and their correlations in women with endometriomas compared to those with benign ovarian cysts or normal pelvic anatomy.

Methods

Between June 2015 and June 2017, a total of 548 women who underwent laparoscopic/laparotomic surgery for ovarian endometriomas (OMA group, n = 226), non-endometriosis benign ovarian cysts (Cyst group, n = 210) and tubal reanastomosis (Control group, n = 112) were recruited in this study. Inflammatory markers including c-reactive protein (CRP), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and coagulation parameters including platelet count, thrombin time (TT), prothrombin time (PT), activated partial thromboplastin time, and plasma fibrinogen as well as CA-125 were determined.

Results

Compared with Cyst group and Control group, TT and PT in OMA group were significantly shorter and plasma fibrinogen levels were significantly higher (P < 0.05). Moreover, the levels of plasma fibrinogen were positively correlated with CRP, NLR and PLR (P < 0.05). In addition, the confidence intervals for the area under the curve (AUC) for CA-125 × fibrinogen were significantly higher than those for CA-125 (0.904–0.952 vs. 0.899–0.949) in the diagnosis of endometrioma.

Conclusions

These results indicate that women with endometriomas demonstrate a hypercoagulable status due to the inflammatory nature of endometriosis. The combined determination for CA-125 and fibrinogen demonstrate a higher area under the curve than the single detection of CA-125 in those with endometriomas compared to these with benign ovarian cysts.

Trial registration

This study was approved by the Human Ethics Committee of the Women’s Hospital, School of Medicine, Zhejiang University (No.20170174) and all women provided written informed consent.

Cellular Components Contributing to Fibrosis in Endometriosis: A Literature Review

Endometriosis-related fibrosis represents a complex phenomenon with underlying mechanisms yet to be clarified. Fibrosis is consistently present in all disease forms and contributes to classic endometriosis-related symptoms of pain and infertility. The purpose of this literature review was to examine the role of various cellular populations and biologic mechanisms and signaling pathways in inducing fibrogenesis of endometriotic lesions. A search was performed through PubMed and MEDLINE for animal and human studies published in English in the last 23 years that examined fibrosis in superficial, ovarian, and deep infiltrating endometriosis. The main cell types found to be involved in the development of fibrosis were platelets, macrophages, ectopic endometrial cells, and sensory nerve fibers. Interactions among each of the cell types contribute to the production of fibrosis through the production of soluble factors, mostly transforming growth factor-β but also other cytokines and neuropeptides. Cell types known to be critical to the pathophysiology of endometriosis also contribute to fibrogenesis, thus supporting the theory that fibrosis is an inherent part of endometriosis.

Anti-inflammatory cytokines in endometriosis

Although the pathogenesis of endometriosis is not fully understood, it is often considered to be an inflammatory disease. An increasing number of studies suggest that differential expression of anti-inflammatory cytokines (e.g., interleukin-4 and -10, and transforming growth factor-β1) occurs in women with endometriosis, including in serum, peritoneal fluid and ectopic lesions. These anti-inflammatory cytokines also have indispensable roles in the progression of endometriosis, including by promoting survival, growth, invasion, differentiation, angiogenesis, and immune escape of the endometriotic lesions. In this review, we provide an overview of the expression, origin, function and regulation of anti-inflammatory cytokines in endometriosis, with brief discussion and perspectives on their future clinical implications in the diagnosis and therapy of the disease.

Increased circulating cell-derived microparticle levels in deep infiltrating endometriosis patients with larger implants

Objective:

Circulating cell-derived microparticles have been reported to be elevated in inflammatory and procoagulant conditions including deep infiltrating endometriosis. The objective of this pilot study was to investigate whether higher circulating cell-derived microparticle levels may be associated with specific clinical features and the extension or severity of deep infiltrating endometriosis.

Methods:

This is an observational analytical cross-sectional study, including three groups of patients undergoing gynecological surgery. The DIE group included 75 patients with deep infiltrating endometriosis, the control group (C group) consisted of 39 patients without endometriosis, and a positive control group was composed of 31 patients with ovarian endometriomas but not deep infiltrating endometriosis (OE group). Venous blood samples for circulating cell-derived microparticle determinations in plasma were obtained before surgery. The following variables were assessed: severe dysmenorrhea, dyspareunia, non-cyclic chronic pelvic pain, dyschezia, dysuria, hematuria, rectal bleeding, sterility, presence of ovarian endometrioma, adenomyosis, and adhesions, rASRM (revised American Society for Reproductive Medicine) stage, Enzian classification, number of sites affected, and the cumulative size of deep infiltrating endometrial implants.

Results:

Circulating cell-derived microparticle levels were statistically higher in the DIE group compared with the C group ( p-value = 0.001). None of the variables analyzed showed higher levels of circulating cell-derived microparticles in the DIE group, except for a significant positive correlation between the cumulative size of deep infiltrating endometrial lesions and circulating cell-derived microparticle levels ( r = 0.264, p = 0.022).

Conclusion:

Patients having deep infiltrating endometriosis with a larger cumulative size of endometriotic implants showed higher circulating cell-derived microparticle levels suggesting an increased inflammatory and/or hypercoagulable systemic status in this more severe form of the disease. Further research is needed to assess our findings and to explore the role of circulating cell-derived microparticles in the pathophysiology of deep infiltrating endometriosis.

Scutellarin Suppresses Platelet Aggregation and Stalls Lesional Progression in Mouse With Induced Endometriosis

Platelets play an important role in the development of endometriosis. Scutellarin is a flavonoid isolated from a medicinal herb traditionally used as a potent antiplatelet agent. In this study, we sought to evaluate its potential therapeutic effect, if any, in mice with induced endometriosis. Endometriosis was induced in 27 female Balb/c mice by intraperitoneal injection of uterine fragments. Two weeks after the induction, the 27 mice were randomly divided in equal sizes into 3 groups: untreated, which received only vehicle, and low-dose and high-dose groups, which received low- and high dose of scutellarin treatment. Hotplate test was administrated to all mice before endometriosis induction, and before and after the scutellarin treatment. Two weeks after the treatment, a blood sample was drawn before sacrifice and all lesions were harvested. The peripheral platelet activation rate and total lesion weight were assessed, and immunohistochemistry and histochemistry analyses were performed to evaluate the extent of proliferation, angiogenesis, fibroblast-to-myofibroblast transdifferentiation (FMT), and fibrosis in lesions. Compared with untreated mice, mice in both low-dose and high-dose groups had significantly reduced lesion weight and improved hyperalgesia. Scutellarin also reduced the peripheral-activated platelets rate and resulted in significantly reduced platelet aggregation, cellular proliferation, angiogenesis, the extent of FMT, and the extent of fibrosis in lesions. Thus, we conclude that scutellarin is efficacious in treating endometriosis in vivo by suppressing platelet aggregation, inhibiting proliferation, angiogenesis, and fibrogenesis, resulting in reduced lesion size and improved pain behavior. As such, scutellarin may be a potentially promising therapeutics for the treatment of endometriosis.

Further Evidence for Hypercoagulability in Women With Ovarian Endometriomas

Our previous studies have shown that platelets play a crucial role in the development of endometriosis, and women with endometriosis appear to be in a state of hypercoagulability. However, a recent study could only replicate part of our previous finding, casting doubts on this notion. We further investigated this question through a cross-sectional study by measuring additional coagulation factors in women with and without endometriosis. To this end, we conducted a cross-sectional study of 100 women with laparoscopically and pathologically diagnosed ovarian endometriomas (OMA) and another 100 women without endometriosis. The platelet count; platelet activation rate; maximum platelet aggregation rate; plasma levels of D-dimer, fibrinogen, fibrin degradation products (FDPs), plasma soluble P-selectin (sP-sel), and prothrombin fragment 1+2 (F1+2); prothrombin time; thrombin time (TT); and activated partial thromboplastin time were measured before surgery and 3 months after surgery, and their clinical data were recorded. These measurements were also performed in control patients. We found that, compared with controls, women with OMA had a significantly higher platelet activation rate and platelet aggregation rate, elevated plasma D-dimer, fibrinogen, FDPs, sP-sel, and F1+2 levels as well as shortened TT. Remarkably, TT was prolonged, and all the other coagulation measurements, except plasma fibrinogen level, were significantly reduced 3 months after surgical removal of endometriotic lesions. Thus, our study provides another piece of evidence that endometriosis is a hypercoagulable disease, and anticoagulation therapy may hold promises in treating endometriosis.

Basic mechanisms of vascularization in endometriosis and their clinical implications

BACKGROUND

Vascularization is a major hallmark in the pathogenesis of endometriosis. An increasing number of studies suggests that multiple mechanisms contribute to the vascularization of endometriotic lesions, including angiogenesis, vasculogenesis and inosculation.

OBJECTIVE AND RATIONALE

In this review, we provide an overview of the basic mechanisms of vascularization in endometriosis and give special emphasis on their future clinical implications in the diagnosis and therapy of the disease.

SEARCH METHODS

Literature searches were performed in PubMed for English articles with the key words 'endometriosis', 'endometriotic lesions', 'angiogenesis', 'vascularization', 'vasculogenesis', 'endothelial progenitor cells' and 'inosculation'. The searches included both animal and human studies. No restriction was set for the publication date.

OUTCOMES

The engraftment of endometriotic lesions is typically associated with angiogenesis, i.e. the formation of new blood vessels from pre-existing ones. This angiogenic process underlies the complex regulation by angiogenic growth factors and hormones, which activate intracellular pathways and associated signaling molecules. In addition, circulating endothelial progenitor cells (EPCs) are mobilized from the bone marrow and recruited into endometriotic lesions, where they are incorporated into the endothelium of newly developing microvessels, referred to as vasculogenesis. Finally, preformed microvessels in shed endometrial fragments inosculate with the surrounding host microvasculature, resulting in a rapid blood supply to the ectopic tissue. These vascularization modes offer different possibilities for the establishment of novel diagnostic and therapeutic approaches. Angiogenic growth factors and EPCs may serve as biomarkers for the diagnosis and classification of endometriosis. Blood vessel formation and mature microvessels in endometriotic lesions may be targeted by means of anti-angiogenic compounds and vascular-disrupting agents.

WIDER IMPLICATIONS

The establishment of vascularization-based approaches in the management of endometriosis still represents a major challenge. For diagnostic purposes, reliable angiogenic and vasculogenic biomarker panels exhibiting a high sensitivity and specificity must be identified. For therapeutic purposes, novel compounds selectively targeting the vascularization of endometriotic lesions without inducing severe side effects are required. Recent progress in the field of endometriosis research indicates that these goals may be achieved in the near future.

Docking of THPDTPI: to explore P-selectin as a common target of anti-tumor, anti-thrombotic and anti-inflammatory agent

The impact of soluble P-selectin on tumor growth, thrombosis and inflammation has been individually documented. Whether the down-regulation of P-selectin expression can simultaneously slow the tumor growth, inhibit the thrombosis and attenuate the inflammatory response remains unknown. In this context, (2'S,5'S)- tetrahydropyrazino[1',2':1,6]-di{2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole}-1',4'-dione (THPDTPI) was designed as an inhibitor of P-selectin. The suitable docking of THPDTPI towards the active site of P-selectin, the significant down-regulation of THPDTPI to P-selectin expression, and the direct action of THPDTPI on P-selectin suggest that P-selectin could be a target of THPDTPI. In vivo THPDTPI possesses the anti-tumor activity, the anti-thrombotic activity and the anti-inflammatory activity. This implies that targeting P-selectin is of essential importance for this triple activity. The minimal effective doses of THPDTPI inhibiting the tumor growth, the rat arterial thrombosis and the mouse ear edema are 0.01 μmol/kg, 0.1 μmol/kg and 0.001 μmol/kg, respectively. Atomic force microscopy images and FT-MS spectra showed that the adhesion of THPDTPI onto the surfaces of the platelets may be the first step of P-selectin targeting. Besides, the dependence of the triple action of THPDTPI inhibiting the tumor growth, the thrombosis and the inflammation on the decrease of the soluble P-selectin led to the correlation of the soluble P-selectin with the serum TNF-α and serum IL-8.

IQCA-TAVV: To explore the effect of P-selectin, GPIIb/IIIa, IL-2, IL-6 and IL-8 on deep venous thrombosis

Deep vein thrombosis (DVT) associates with considerable morbidity, functional disability and mortality. Due to the lack of suitable inhibitor the correlation of various factors in DVT onset remains unknown. In this context we analyzed the structure of anti-platelet aggregation agent, P-selectin down-regulator, GPIIb/IIIa down-regulator and anti-inflammatory agent, thereby designed N-(3S-1,2,3,4-tetrahydroisoquinoline-3-carbonyl)- Thr-Ala-Arg-Gly-Asp(Val)-Val (IQCA-TAVV) as an inhibitor of DVT to receive evaluations. The docking predicted that IQCA-TAVV can target P-selectin and GPIIb/IIIa. The UV showed that IQCA-TAVV can act on P-selectin and GPIIb/IIIa. ELISA indicated that IQCA-TAVV concentration dependently inhibited activated platelets to express P-selectin and GPIIb/IIIa, and the minimal effective concentration was 1 nM. IC50 of IQCA-TAVV against platelet aggregation induced by arachidonic acid, adenosine diphosphate and platelet activating factor fell within a range of 0.13 nM to 0.30 nM. In vivo IQCA-TAVV dose-dependently inhibited venous thrombosis and the minimal effective dose was 1 nmol/kg. On ear edema model the anti-inflammation activity of 10 nmol/kg IQCA-TAVV equaled that of 1.1mmol/kg aspirin. The concentration of IL-2, IL-6 and IL-8 in the serum of the ear edema mice were also significantly decreased by 10 nmol/kg IQCA-TAVV. Even at 1 μmol/kg of dose IQCA-TAVV still did not injure the kidney, the liver, and the nerves of healthy mice. Thereby IQCA-TAVV depicts a relationship of three levels (inhibiting platelet activation, targeting externalized membrane receptor, decreasing serum inflammatory factor) for the down-regulation of P-selectin, GPIIb/IIIa, IL-2, IL-6 and IL-8 in DVT.

Platelets impair natural killer cell reactivity and function in endometriosis through multiple mechanisms

Study question

Do platelets have any role in the reduced cytotoxicity of natural killer (NK) cells in endometriosis?

Summary answer

Platelets impair NK cell reactivity and function in endometriosis through multiple mechanisms.

What is known already

Platelets play an important role in the development of endometriosis, and platelet-derived transforming growth factor-β1 (TGF-β1) suppresses the expression of NK Group 2, Member D (NKG2D) on NK cells, resulting in reduced cytotoxicity in women with endometriosis.

Study design size, duration

Experiments on mice with induced endometriosis in which either platelets, NK cells or both were depleted and controls (none depleted). In vitro experiments with NK cells, platelets and, as target cells, endometriotic epithelial cell and endometrial stromal cell lines.

Participants/materials setting methods

Immunohistochemistry analysis of ectopic endometrial tissues from mice with induced endometriosis receiving either platelet depletion (PD), NK cell depletion, or both or none. Immunofluorescence, flow cytometry and gene expression analysis for major histocompatibility complex class I (MHC-I) expression in target cells. Cytotoxicity and degranulation assays and the measurement of interferon (IFN)-γ secretion for the evaluation of NK cytotoxicity. Flow cytometry and gene expression for the expression of NK cell receptors.

Main results and the role of chance

PD resulted in significantly reduced lesion weight in mice with induced endometriosis, but NK cell depletion as well as concomitant platelet and NK cell depletion increased the weight, suggesting that the anti-endometriosis effect of PD is mediated, at least in part, by increased NK cell cytotoxicity against endometriotic cells. Co-incubation of target cells with platelets resulted in rapid platelet coating as well as increased MHC-I expression in these cells, effectively providing a cloak of 'pseudo-self' to these cells to shield against NK cell lysis. It also reduced the expression of NKG2D ligands MICA and MICB and reduced the NK cell cytotoxicity. In addition, co-incubation of NK cells with platelets impaired the NK cell cytotoxicity as well. This impaired NK cell cytotoxicity was not due to the increased NK cell apoptosis, but, rather, through reduced NK cell degranulation and IFN-γ production, and reduced expression of activating receptors NKG2D and NKp46 and increased expression of inhibitory receptor KIR2DL1 in NK cells. Inhibition of TGF-β1 signaling partially restored the aberrant expression of NKG2D, NKp46 and KIR2DL1, and partially restored the impaired NK cell cytotoxicity induced by activated platelets and their releasate.

Large scale data

Not applicable.

Limitations reasons for caution

This study is confined by the limitation of animal and in vitro experimentation and the lack of direct human data.

Wider implications of the findings

Anti-platelet treatment holds promise in treating endometriosis.

Study funding/competing interests

The National Natural Science Foundation of China (81471434 to S.W.G., 81270676 to S.W.G., 81370695 to X.S.L. and 81671436 to X.S.L). None of the authors has anything to disclose.

Inhibitory effect of curcumin in human endometriosis endometrial cells via downregulation of vascular endothelial growth factor

Endometriosis, which affects up to 10% of women of reproductive age, is defined as endometrial-like gland and stroma tissue growths outside the uterine cavity. Despite increasing research efforts, there are no current effective treatment methods for this disease, therefore investigations for therapeutic strategies are of primary concern. In preliminary work, the authors demonstrated that curcumin inhibits endometriosis in vivo. The present in vitro study aimed to investigate the association between endometriotic stromal cells and curcumin and to clarify the underlying mechanism of action. A total of 14 patients with endometriosis were enrolled in the present study. The purity of endometrial stromal cell cultures was proven by standard immunofluorescent staining of vimentin. The cell proliferation and curcumin effects on endometrial stromal cells were assessed by the MTT assay and Hematoxylin and Eosin staining. For cell cycle analysis, phase distribution was detected by flow cytometry. Vascular endothelial growth factor (VEGF) protein expression was examined using immunohistochemistry staining. Apoptosis was assessed using Annexin V‑fluorescein isothiocyanate staining. The results indicated that the treatment of curcumin decreased human ectopic and eutopic stromal cell growth. Following treatment with curcumin, human endometriotic stromal cells demonstrated an increased percentage of G1‑phase cells and decreased percentages of S‑phase cells, particularly in the group treated with 50 µmol/l curcumin. Treatment with curcumin additionally decreased expression of VEGF. The data provide evidence that curcumin reduces cell survival in human endometriotic stromal cells, and this may be mediated via downregulation of the VEGF signaling pathway.

Enhancer of Zeste homolog 2 (EZH2) induces epithelial-mesenchymal transition in endometriosis

EZH2, a subunit of the polycomb repressive complex 2 (PRC2) catalyzing trimethylation of histone H3 lysine 27 (H3K27), induces epithelial-mesenchymal transition (EMT) in cancers. However, whether EZH2 regulates EMT in endometriosis is unclear. Here, we show that EZH2 expression, along with its associated PRC2 proteins, is significantly elevated in ectopic and eutopic endometrium from women with endometriosis as compared with control endometrium. EZH2 knockdown or inhibition restored the epithelial phenotypes of endometriotic epithelial cells, concomitant with the upregulation of E-cadherin and downregulation of vimentin and transcription factors (Snail and Slug) as well as reduced cellular migratory and invasive propensity. Conversely, overexpression of EZH2 induced the expression of Snail, Slug and vimentin and suppresses E-cadherin expression. In vivo administration of 3-Deazaneplanocin A (DZNep), an EZH2 inhibitor, significantly inhibited the growth of endometriotic lesions and improved generalized hyperalgesia, along with attenuated EMT and reduced fibrosis in endometriosis. Notably, platelets induced EZH2 upregulation and increased H3K27 and H3K9 trimethylation levels in endometriotic epithelial cells. These data identify EZH2 as a novel driver of EMT in endometriosis, implicates the link between wound healing and epigenetic changes in the context of endometriosis, and underscore the role of platelets in the development of endometriosis.

Social psychogenic stress promotes the development of endometriosis in mouse

Exposure to chronic stress before and well after the induction of endometriosis is reported to increase lesion sizes in rats, but it is unclear whether stress, exposed shortly after the induction of endometriosis, would also promote the development of endometriosis, nor is it clear what the underlying possible molecular mechanism is. This study was undertaken to test the hypothesis that chronic stress can promote the development of endometriosis. A prospective randomized mouse experiment was conducted that subjected mice with induced endometriosis to predator stress. In addition, a cross-sectional immunohistochemistry study was performed in ectopic and eutopic endometrial tissue samples from age- and roughly menstrual phase-matched women with ovarian endometriomas. It was found that the chronic psychogenic stress induced epigenetic changes in the hippocampus in mouse independent of endometriosis. It was also found that chronic psychogenic stress induced epigenetic changes in the hippocampus of mice with endometriosis, and seemingly activated the adrenergic signalling in ectopic endometrium, resulting in increased angiogenesis and accelerated growth of endometriotic lesions. Thus, chronic psychogenic stress promotes endometriosis development, raising the possibility that the use of anti-depressants in cases of prolonged and intense stress might forestall the negative impact of stress on the development of endometriosis.

Progressive development of endometriosis and its hindrance by anti-platelet treatment in mice with induced endometriosis

We have recently shown that platelets drive smooth muscle metaplasia (SMM) and fibrogenesis in endometriosis through epithelial-mesenchymal transition (EMT) and fibroblast-to-myofibroblast transdifferentiation (FMT). To see whether this is true in vivo, this prospective, randomized, and serially evaluated mouse investigation was conducted. Endometriosis was induced in female Balb/C mice, which were then randomly divided into two groups: Tanshinone IIA (TAN) and control (CTL) groups. TAN mice were treated with TAN but CTL mice received none. Every week until the 6th week after induction, five mice from each group were killed. Lesion weight was measured and lesion samples were subjected to immunohistochemistry and histochemistry analysis of platelet aggregation (CD41), E-cadherin, TGF-β1, phosphorylated Smad3, α-SMA, collagen I, CCN2, LOX, desmin and SM-MHC, and the extent of fibrosis was evaluated by Masson trichrome staining. It was found that endometriotic lesions exhibited progressive cellular changes consistent with the progressive EMT, FMT, SMM, and fibrogenesis. TAN treatment resulted in significant hindrance of EMT, FMT, SMM and fibrogenesis, and reduced lesion weight (all P-values <0.05). These data corroborate the notion that endometriotic lesions undergo progressive EMT and FMT, giving rise to SMM and ultimately fibrosis. This understanding sheds new light onto the natural history of endometriosis.

Anti-platelet therapy holds promises in treating adenomyosis: experimental evidence

BACKGROUND

Recently emerging evidence indicates that endometriotic lesions are wounds undergoing repeated tissue injury and repair (ReTIAR), and platelets induce epithelial-mesenchymal transition (EMT), fibroblast-to-myofibroblast transdifferentiation (FMT), leading ultimately to fibrosis. Due to the commonality of cyclic bleeding as in endometriosis, adenomyotic lesions are also wounds that undergo ReTIAR, and we have recently provided evidence corroborating platelet-induced EMT, FMT and fibrogenesis in adenomyosis. This study sought to evaluate the effect of antiplatelet therapy in a mouse model of adenomyosis.

METHODS

Adenomyosis was induced in 57 female ICR mice with neonatal dosing of tamoxifen, while another 12 (group C) were dosed with solvent only, serving as a blank control. Starting from 4 weeks after birth, hotplate test was administrated to all mice every 4 weeks. At the 16th week, all mice with induced adenomyosis were randomly divided into 6 groups: untreated, low- and high-dose Ozagrel, low- and high-dose anti-mouse GPIbα polyclonal IgG antibody to deplete platelets, and isotype-matched inert IgG non-immune antibody. Group C received no treatment. After 3 weeks of treatment, they were hotplate tested again, their uterine horns and brains were harvested, and a blood sample was taken to measure the plasma corticosterone level by ELISA. The left uterine horn was used for immunohistochemistry analysis. The brainstem nucleus raphe magnus (NRM) sections were subjected to immunofluorescence staining for GAD65. The depth of myometrial infiltration and uterine contractility were evaluated.

RESULTS

We found that both Ozagrel treatment and platelet depletion dose-dependently suppressed myometrial infiltration, improved generalized hyperalgesia, reduced uterine contractility, and lowered plasma corticosterone levels, improved the expression of some proteins known to be involved in adenomyosis and slowed down the process of fibrogenesis. It also elevated the number of GAD65-expressing neurons in the brainstem NRM, possibly boosting the GABAergic inhibition of pain due to adenomyosis.

CONCLUSION

This study further provides evidence that platelets play important roles in the development of adenomyosis. Anti-platelet treatment is efficacious in suppression of myometrial infiltration, improving generalized hyperalgesia, reducing uterine hyperactivity and systemic corticosterone levels. Collectively, these results demonstrate that anti-platelet therapy seems to be promising for treating adenomyosis.

Pharmacologic treatment of the ovarian endometrioma

INTRODUCTION

Treatment of ovarian endometriomas is commonly achieved through laparoscopic surgery and this can be effective in eliminating the disease, although a majority of recent trials documented an adverse effect of surgery on ovarian reserve markers. With the advancement in imaging techniques, ovarian endometriomas are increasingly diagnosed at an earlier stage when the endometrioma may be smaller, less fibrotic and more responsive to medical treatment, making an evaluation of medical options critically important.

AREAS COVERED

The review focuses on currently utilized pharmacologic therapies for endometrioma (oral contraceptives, the levonorgestrel-releasing IUS, the hormone-releasing subdermal implant, Implanon); experimental and future treatments are also mentioned (GnRH antagonists, progesterone receptor modulators, antioestrogens, newer subdermal implants and intracystic administration of pharmacologic agents). Finally, the usefulness of post-operative adjuvant medical treatments is discussed Expert opinion: Today, reliable, non-invasive diagnostic procedures of an ovarian endometrioma are available and should be utilized to identify its presence and type of pathology. In a young patient, classic medical therapies such as oral contraceptives and synthetic progestins should be tried first to alleviate symptoms. Only when these regimens fail, should a minimally invasive surgery be envisaged. Following endoscopic surgery, adjuvant medical treatment may reduce recurrence of both symptoms and the lesion.

Platelets drive smooth muscle metaplasia and fibrogenesis in endometriosis through epithelial-mesenchymal transition and fibroblast-to-myofibroblast transdifferentiation

Smooth muscle metaplasia (SMM) and fibrotic tissues are frequently seen in endometriotic lesions, yet the mechanisms underlying their formation are poorly understood. In this study, we investigated the roles of activated platelets in driving epithelial-mesenchymal transition (EMT) and fibroblast-to-myofibroblast transdifferentiation (FMT) in endometriosis. Through in vitro experimentations, we found that activated platelets, through the release of TGF-β1 and the induction of TGF-β/Smad signaling pathway, promoted EMT and FMT in endometriosis, resulting in increased cell contractility, collagen production, and ultimately to fibrosis. TGF-β blockade reversed these processes. Prolonged exposure of endometriotic stromal cells to activated platelets induced increased expression of α-SMA as well as markers of differentiated smooth muscle cells. Consequently, endometriotic lesions and their microenvironment contain all the necessary molecular machinery to promote SMM and fibrogenesis. Our results suggest that endometriotic lesions are wounds that undergo repeated injury and healing, highlighting the importance of platelets in the development of endometriosis.

Platelet-derived TGF-β1 mediates the down-modulation of NKG2D expression and may be responsible for impaired natural killer (NK) cytotoxicity in women with endometriosis

STUDY QUESTION

Does platelet-derived transforming growth factor-β1 (TGF-β1) have any role in the reduced cytotoxicity of natural killer (NK) cells in women with endometriosis?

SUMMARY ANSWER

Platelet-derived TGF-β1 suppresses the expression of NK Group 2, Member D (NKG2D) on NK cells, resulting in reduced cytotoxicity in women with endometriosis, but neutralization of TGF-β1 reverses the reduction.

WHAT IS KNOWN ALREADY

NK cells are cytotoxic lymphocytes that play an important role in peritoneal immune surveillance, and their function is known to be impaired in women with endometriosis. There is increased platelet aggregation in endometriotic lesions and increased platelet activation rate in the peripheral blood in women with endometriosis, yet activated platelets release copiousTGF-β1, which is known to be a potent immunosuppressive molecule that suppresses NK cell function and NKG2D expression.

STUDY DESIGN, SIZE, DURATION

Cross-sectional clinical studies of 30 women with endometriosis and 33 women without endometriosis and in vitro experimentation with and without TGF-β1 blockade.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Peritoneal fluid (PF) samples from premenopausal women with endometriosis and age- and menstrual phase-matched controls were collected. Platelet count, white blood cell (WBC) count, mean platelet volume (MPV), platelet activation rate, TGF-β1 concentration, expression levels of NKG2D on NK cells in the PF were evaluated. The apoptosis of freshly isolated NK cells treated with PF from women with endometriosis, the NK cytotoxicity and NKG2D expression treated with PF in the presence or absence of an anti-TGF-β1 antibody were also determined.

MAIN RESULTS AND THE ROLE OF CHANCE

The platelet count, WBC count, MPV, platelet activation rate and the TGF-β1 concentration in the PF from women with endometriosis were significantly elevated when compared with those of women without endometriosis. The TGF-β1 concentration correlated positively with the platelet activation rate (r = 0.59, P < 0.01), suggesting that activated platelets are responsible, at least in part, for the increased TGF-β1 concentration. The cytotoxicity of freshly isolated NK cells treated with PF of women with endometriosis is significantly reduced when compared with that of women without endometriosis. Both the platelet activation rate and the TGF-β1 concentration in the PF correlated negatively with the NKG2D expression in NK cells isolated from the PF (r = -0.36, P < 0.01, and r = -0.45, P < 0.01, respectively). In addition, the NKG2D expression level and the cytotoxicity in freshly isolated NK cells were found to be significantly reduced if co-cultured with PF from women with endometriosis, but the TGF-β1 blockade effectively reverses the reduction.

LIMITATIONS, REASONS FOR CAUTION

This study is limited by the cross-sectional nature of the study.

WIDER IMPLICATIONS OF THE FINDINGS

NKG2D is known to potently activate NK cells, so potent that it even overrides inhibitory signals transduced by other inhibitory receptors. This is the first time we demonstrate that platelet-derived TGF-β1 may be responsible for reduced NKG2D expression as well as reduced cytotoxicity of NK cells in women with endometriosis. This study provides yet another piece of evidence that platelets play critical roles in the development of endometriosis, and anti-platelet treatment should improve NK cell functionality in treating endometriosis. Equally important, this study highlights the critical role of the lesion microenvironment in shaping NK cell-mediated anti-endometriotic immunity.

STUDY FUNDING/COMPETING INTERESTS

This research was supported in part by grants 81270676 (S.-W.G.), 81471434 (S.-W.G.), 81530040 (S.-W.G.), and 81370695 (X.L.) from the National Natural Science Foundation of China, and grant 2013ZYJB0019 (X.L.) from Shanghai Municipal Commission of Health and Family Planning. None of the authors has anything to disclose.

Cellular Changes Consistent With Epithelial-Mesenchymal Transition and Fibroblast-to-Myofibroblast Transdifferentiation in the Progression of Experimental Endometriosis in Baboons

We have recently shown that platelets play important roles in development of endometriosis and proposed that endometriotic lesions are essentially wounds that undergo repeated tissue injury and repair (ReTIAR). Further investigation indicated that endometriotic lesions, stimulated by platelet-derived transforming growth factor β1 (TGF-β1), activate the TGF-β1/Smad3 signaling pathway and undergo epithelial-mesenchymal transition (EMT) and fibroblast-to-myofibroblast transdifferentiation (FMT), resulting in increased cellular contractility and collagen production and increased smooth muscle metaplasia (SMM), leading to fibrosis. Using serially dissected endometriotic tissue samples from baboons with induced endometriosis, we tested the hypothesis of progressive EMT, FMT, SMM, and fibrosis through TGF-β1/Smad activation using immunohistochemistry and immunoflurescence staining analyses. We found that platelets are aggregated in endometriotic lesions, and vimentin expression was increased in the epithelial compartment of the lesions as they progressively developed. We also found that the number of smooth muscle cells (SMCs) appeared to increase with time as lesions progressed and was concomitant with the increased vimentin-positive glandular epithelial cells in the lesions. As lesion development progressed, TGF-β1 and phosphorylated-Smad3 staining was elevated and the number of α-smooth muscle actin-positive myofibroblasts and highly differentiated SMCs increased in the stromal compartment, which correlated with the increasing extent of fibrosis. These results, taken together, provide support for the notion that ReTIAR occurs in the endometriotic lesions, resulting in EMT and FMT, leading to SMM and ultimately fibrosis as lesions progress. Consequently, our data also provide corroborative evidence that platelets drive the EMT and FMT in endometriotic lesions over time, promoting SMM and resulting ultimately in fibrosis in the endometriotic lesions. These findings cast a new light on the natural history of endometriosis which so far has been elusive.

Endometriosis-Derived Stromal Cells Secrete Thrombin and Thromboxane A2, Inducing Platelet Activation

Platelets have been recently revealed to play important roles in the development of endometriosis. However, it is unclear whether endometriotic lesions can secrete any platelet inducers outside the menstruation window. Hence, this study was undertaken to see whether endometriosis-derived stromal cells secrete platelet activators and cause platelet activation. We employed in vitro experimentation using primary ectopic endometrial stromal cells (EESCs) and platelets from healthy male volunteers and evaluated the extent of platelet aggregation by aggregometer and the platelet activation rate by flow cytometry using supernatants harvested from EESCs of different cell densities. We also measured the concentration of thromboxane B2 (TXB2), a metabolite of thromboxane A2 (TXA2), and thrombin activity in supernatants harvested from EESCs of different densities and evaluated the extent of platelet aggregation after treatment of EESCs with hirudin, Ozagrel, and apyrase. Finally, the concentration of TXB2, thrombin, and transforming growth factor β1 (TGF-β1) in platelets cocultured with different densities of EESCs is measured by enzyme-linked immunosorbent assay. We found that EESCs secrete thrombin and TXA2 and induce platelet activation and aggregation in a density-dependent fashion. Treatment of platelets with EESCs resulted in increased concentration of TXB2, thrombin, and TGF-β1 in a density-dependent manner. Treatment of EESCs with hirudin and Ozagrel, but not apyrase, resulted in significant suppression of platelet aggregation. Thus, given recently reported effects of activated platelets on the cell behaviors of EESCs and endometriotic lesions in general, our findings establish that endometriotic lesions and platelets engage active cross-talks in the development of endometriosis, highlighting the importance of lesion microenvironment in endometriosis.

Endometriosis and ovarian cancer: potential benefits and harms of screening and risk-reducing surgery

Although endometriosis is well recognized as a benign gynecologic condition, its association with ovarian cancer (OVCA) has frequently been reported. Review articles on this topic are voluminous, yet there seems to be no consensus as to whether endometriosis is truly a precursor of OVCA and whether any screening or risk-reducing surgery should be instituted, on the basis of our current knowledge. In this review, published data are compiled and critically appraised. Through this critical appraisal, it seems clear that the strongest evidence seems to come from prevalence data. This type of data also suggests a reduced risk of certain histotypes (mainly type II) of OVCA in women with endometriosis. This may explain the rather moderate increase in risk as shown in epidemiologic studies. Even with this moderate increase in OVCA risk, caution should be exercised because of apparent bias in favor of publication of positive results, extensive heterogeneities among prevalence estimates, and inverse relationship between estimates and sizes of the studies. Many molecular studies are conflicting, and earlier studies showing molecular aberrations involved in genomic instability and mutation that enable malignant transformation are not replicated in later studies. Given the low incidence of OVCA and the rather moderate increase in risk of mostly type I tumors, screening seems to be ill-advised, and risk-reducing surgery such as salpingectomy with or without oophorectomy does not seem to yield any substantial benefit to women with endometriosis.

Activated Platelets Induce Estrogen Receptor β Expression in Endometriotic Stromal Cells

BACKGROUND/AIMS

Endometriosis is viewed first and foremost as an estrogen-dependent disease, featuring not only excessive estrogen production but also aberrant expression of estrogen receptors (ERs), particularly ERβ, that mediate the estrogen action. ERβ is the predominant ER in mediating estrogen action in endometriosis, and estrogen plays a vital role in the development of endometriosis; thus, ERβ is viewed as a strong candidate for therapeutic targeting. Given our recent finding that platelets aggregate in endometriotic lesions, we sought to investigate whether activated platelets can upregulate ERβ.

METHODS

Using primary endometriotic stromal cells derived from patients with ovarian endometriomas and platelets harvested from healthy donors, we performed real-time RT-PCR analysis of mRNA abundance (n = 8) and Western blot analysis of protein expression (n = 8) of ERα and ERβ when co-cultured with phosphate-buffered saline, platelets, thrombin alone, and platelets plus thrombin for 48 h.

RESULTS

Treatment of endometriotic stromal cells with activated platelets resulted in the upregulation of ERβ gene and protein expression.

CONCLUSION

In the presence of aggregated and thus activated platelets in endometriotic lesions, ERβ, but not ERα, is upregulated in endometriotic stromal cells. Our result suggests that the use of antiplatelet therapy may have potential in the treatment of endometriosis.