Endometriosis and adenomyosis: Similarities and differences.

Deep endometriosis and uterine adenomyosis are two frequently encountered conditions affecting approximately 200 million women worldwide. They are closely related, showing similar histological patterns and multiple common pathogenic features, and share the same symptoms. It is therefore not surprising that they are often thought to have a common developmental origin. Indeed, both deep endometriosis and adenomyosis appear to derive from estrogen-dependent overproliferation of endometrial tissue and its subsequent implantation in ectopic sites. Although the scientific community has shown increasing interest in these diseases over recent years, neither pathogenesis has yet been elucidated, so there are currently no efficient treatment options. Understanding the mechanisms underlying disease development, as well as discerning their relationship, are key to improving clinical management for millions of patients. The aims of this review are to summarize current knowledge on deep endometriosis and adenomyosis pathogeneses and discuss the possibility that these two entities are actually differential phenotypes of the same disease.

Are lower levels of apoptosis and autophagy behind adenomyotic lesion survival?

RESEARCH QUESTION: How are markers of cell death, invasiveness and progesterone signalling expressed in endometrium and ectopic lesions from adenomyosis patients? DESIGN: Formalin-fixed paraffin-embedded tissue was collected from 15 control and 15 adenomyosis participants . To assess cell survival capacity, caspase 3 and microtubule-associated proteins 1A/1B light chain 3B (LC3B) were immunolabelled as markers of apoptosis and autophagy respectively. Matrix metalloproteinase 9 (MMP9) expression served as a marker of extracellular matrix degradation and invasion activity. Progesterone receptors were immunostained to detect evidence of progesterone resistance. RESULTS: Caspase 3 expression was significantly lower in the stromal (P = 0.0013) and epithelial (P = 0.0157) compartments of adenomyotic lesions than in healthy endometrial tissue. In the stroma, caspase 3 expression was significantly weaker in lesions than in corresponding eutopic endometrium (P = 0.0006). LC3B immunostaining was significantly decreased in adenomyotic stroma compared with corresponding eutopic endometrium (P = 0.0349). A significantly higher expression of MMP9 was detected in eutopic stroma from adenomyosis patients than in healthy tissue (P = 0.0295). Progesterone receptor immunostaining was found to be significantly weaker in the stroma of endometrium and ectopic lesions from adenomyosis patients than disease-free women (P = 0.0001; P = 0.0021). CONCLUSIONS: Adenomyotic lesions show lower levels of apoptosis and autophagy, suggesting that aberrant cell survival may be involved in disease pathogenesis. MMP9 appears to contribute to endometrial invasiveness in adenomyosis, as its expression is more pronounced in endometrium from these women than women without the disease. Evidence of progesterone resistance can be found in endometrium and ectopic lesions from adenomyosis patients, and may drive disease development and account for the failure of certain patients to respond to progestogens.

M2 macrophages enhance endometrial cell invasiveness by promoting collective cell migration in uterine adenomyosis.

RESEARCH QUESTION: Are M2 macrophages implicated in endometrial invasiveness in adenomyosis? DESIGN: Seventeen formalin-fixed paraffin-embedded uterine samples and 16 fresh endometrial biopsies were collected from women with or without adenomyosis. Double immunofluorescence was performed to determine the predominant macrophage population in adenomyosis between M1 and M2 phenotypes. The invasion capacity of endometrial cells was assessed by invasion assays and quantitative polymerase chain reaction for genes involved in cell motility and epithelial-mesenchymal transition (EMT). Specific mechanisms of invasion were investigated by immunohistochemistry for E-cadherin, N-cadherin and matrix metalloproteinase 9 (MMP9). RESULTS: Only M2 macrophages were found to accumulate in adenomyosis, in higher numbers in both eutopic endometrium (P = 0.0109) and lesions (P = 0.0267) than healthy tissue. Co-culture with M2 macrophages significantly boosted invasion capacity in endometrial epithelial (P = 0.0002; P = 0.002) and stromal cells (P = 0.0469; P = 0.0047) from both adenomyosis patients and healthy controls. No gene expression differences indicating EMT were noted, either between co-cultured and control cells, or between healthy and adenomyotic cells. E- and N-cadherin protein expression did not differ significantly between endometrium from adenomyosis subjects and healthy tissue but MMP9 expression was increased in eutopic stroma from adenomyosis patients (P = 0.0492). In adenomyosis, both E-cadherin (P = 0.0379) and N-cadherin (P = 0.0196) were more extensively expressed in basal glands than functional glands. CONCLUSIONS: M2 macrophages accumulate in adenomyosis and enhance invasion capacity of adenomyotic and even healthy endometrial cells, implying that macrophage infiltration alone may be sufficient to promote the disease. This study failed to detect any changes pointing to EMT, suggesting an alternative mode of invasion. Strong E- and N-cadherin-positive intercellular junctions in basal (invasive) glands suggest the involvement of collective cell migration in the invasion process of endometrium.

Conservative Management of Uterine Adenomyosis: Medical vs. Surgical Approach.

Uterine adenomyosis is a commonly encountered estrogen-dependent disease in reproductive-age women, causing heavy menstrual bleeding, intense pelvic pain, and infertility. Although adenomyosis was previously considered a disease of multiparous women, it is becoming increasingly evident that it also affects younger nulliparous women and may compromise their fertility potential. It is clear that hysterectomy, the standard approach to definitively manage the disease, is not an option for patients wishing to preserve their fertility, so there is an urgent need to develop novel conservative strategies. We searched the current literature for available methods for conservative management of adenomyosis, including both pharmacological and surgical approaches. There is no existing drug that can cure adenomyosis at present, but some off-label treatment options may be used to tackle disease symptoms and improve fertility outcomes. Adenomyosis in patients wishing to conceive can be 'treated' by conservative surgery, though these procedures require highly experienced surgeons and pose a considerable risk of uterine rupture during subsequent pregnancies. While currently available options for conservative management of adenomyosis do have some capacity for alleviating symptoms and enhancing patient fertility perspectives, more effective new options are needed, with gonadotropin-releasing hormone antagonists showing encouraging results in preliminary studies.

Pathogenesis of Endometriosis: New Insights into Prospective Therapies.

Endometriosis is a female reproductive disorder characterized by growth of uterine cells and tissue in distant sites. Around 2-10% of women experience this condition during reproductive age, 35-50% of whom encounter fertility issues or pain. To date, there are no established methods for its early diagnosis and treatment, other than surgical procedures and scans. It is difficult to identify the disease at its onset, unless symptoms such as infertility and/or pain are present. Determining the mechanisms involved in its pathogenesis is vital, not only to pave the way for early identification, but also for disease management and development of less invasive but successful treatment strategies. Endometriosis is characterized by cell proliferation, propagation, evasion of immunosurveillance, and invasive metastasis. This review reports the underlying mechanisms that are individually or collectively responsible for disease establishment and evolution. Treatment of endometriosis mainly involves hormone therapies, which may be undesirable or have their own repercussions. It is therefore important to devise alternative strategies that are both effective and cause fewer side effects. Use of phytochemicals may be one of them. This review focuses on pharmacological inhibitors that can be therapeutically investigated in terms of their effects on signaling pathways and/or mechanisms involved in the pathogenesis of endometriosis.

Identifying Common Pathogenic Features in Deep Endometriotic Nodules and Uterine Adenomyosis.

Increasing imaging data point to a link between deep endometriotic nodules (DENs) and uterine adenomyosis (AD). The study aimed to investigate this link at the histological level and detect potential features shared by the two diseases. We collected formalin-fixed paraffin-embedded tissue (endometrium and lesions) from women with DENs of the rectovaginal septum (n = 13), AD (n = 14), and control subjects (n = 14). Immunohistochemical analyses of CD41 and CD68 were conducted to explore the roles of platelets and macrophages, respectively. Picrosirius red staining was carried out to gather evidence of fibrosis. Vascular endothelial growth factor (VEGF) was assessed, and total numbers of CD31-positive vessels were calculated to investigate the mechanism governing angiogenesis. Double immunohistochemistry for CD31 and alpha smooth muscle actin (αSMA) was performed to discern stable vessels. Platelet aggregation was significantly decreased in both types of lesions compared to their corresponding eutopic endometrium and healthy controls. Macrophage numbers were higher in both lesions than in their corresponding endometrium and healthy subjects. Significantly higher rates of collagen accumulation were detected in DENs and AD lesions compared to their corresponding eutopic and healthy endometrium. VEGF expression was downregulated in the stromal compartment of AD lesions compared to the healthy endometrium. The total number of vessels per area was significantly higher in DENs and AD lesions than in the healthy endometrium. Rates of αSMA-surrounded vessels were decreased in DENs and AD lesions compared to their corresponding eutopic and healthy endometrium. We report common pathogenic mechanisms between DENs and AD, namely excessive macrophage accumulation, fibrosis, and irregular angiogenesis. Our results further support the notion of DENs and AD being linked at the histological level.

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

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

Investigation of the role of platelets in the aetiopathogenesis of adenomyosis.

RESEARCH QUESTION: Do platelets aggregate in adenomyotic lesions and participate in adenomyosis pathogenesis and related fibrosis? DESIGN: Eutopic and ectopic endometrium from 17 patients with adenomyosis and endometrium from 23 healthy controls were collected. Immunohistochemical analyses of platelet marker CD41, transforming growth factor beta 1 (TGF-ß1) and vascular endothelial growth factor (VEGF) were performed to investigate aggregation and activation of platelets in the stroma. Picrosirius staining was carried out to evaluate the extent of fibrotic tissue. RESULTS: Stroma in the control group showed higher CD41 staining levels than ectopic stroma from patients with adenomyosis (P < 0.001). In patients with adenomyosis, eutopic stroma expressed more extensive CD41 staining than ectopic stroma (P < 0.0001). Stroma in the control group exhibited higher TGF-ß1 expression than eutopic and ectopic stroma from adenomyosis patients (P = 0.009 and P < 0.0001). Stroma in the control group also expressed higher VEGF levels than ectopic stroma from patients with adenomyosis (P < 0.001). In patients with adenomyosis, eutopic stroma showed higher VEGF expression than ectopic stroma (P = 0.021). Stroma in ectopic endometrium from adenomyosis patients displayed greater Picrosirius staining compared with both eutopic stroma from adenomyosis patients and stroma in the control group (P < 0.0001). CONCLUSION: The results of this study did not detect a primary role for platelet activation or aggregation in the pathophysiological process of adenomyosis. Higher rates of collagen fibres were found in adenomyotic lesions, likely to be related to a TGF-ß1-independent pathway. Collagen fibre deposition was more extensive in adenomyotic lesions, consistent with fibrosis.

Origin and Pathogenic Mechanisms of Uterine Adenomyosis: What Is Known So Far.

Uterine adenomyosis is a benign disease, commonly encountered in reproductive-age women and responsible for chronic pelvic pain, abnormal uterine bleeding, and infertility. Although the exact origin and pathogenic mechanisms involved in adenomyosis still need to be elucidated, significant progress has been made over recent years. Ever since the theory of endometrium invaginating the myometrium via a traumatized interface was first proposed, numerous molecular mechanisms have been reported to participate in this process. At the same time, an alternative theory has suggested de novo development of adenomyotic lesions from metaplasia of Müllerian remnants or adult stem cells. Hence, our understanding of the pathogenesis of adenomyosis has been greatly enhanced and is anticipated to pave the way for development of an effective and safe treatment. The goal of this review is to analyze current knowledge on the origin and pathogenic mechanisms of adenomyosis, ranging from the most widely accepted theories to newly reported data.

Answer to Controversy: miR-10a Replacement Approaches Do Not Offer Protection against Chemotherapy-Induced Gonadotoxicity in Mouse Model.

It is well known that chemotherapeutic agents may lead to premature ovarian failure and infertility. Therefore, fertility preservation is highly recommended for female cancer survivors. Despite the currently available techniques, new, non-invasive methods need to be developed to protect the ovarian follicles during oncological treatments. MicroRNAs can be effective tools in this field, as they alter their expression during chemotherapy exposure, and hence they can be useful to minimize the off-target toxicity. Previously, we identified several miRNAs with an important role in newborn mouse ovaries exposed to chemotherapy; among them, the miR-10a was one of the most downregulated miRNAs. Given the controversial role of miR-10a in the ovarian function, we decided to investigate its implication in chemotherapy-induced gonadotoxicity. The downregulated levels of miR-10a were restored by a liposome system conjugated with a mimic miR-10a, and the overexpressed miR-10a prevented the upregulation of the targeted gene, phosphatase and tensin homolog (Pten). The apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) Assay and Bax expression quantification, while histological studies were also performed to evaluate the follicle count and development. Our results showed that the miR-10a replacement could not protect the ovaries from chemotherapy-induced apoptosis, whereas the targeting of Pten may affect the follicle activation via the phosphoinositide 3-kinase (PI3K)/PTEN/protein kinase B (AKT) pathway. Consequently, the application of miR-10a in fertility preservation is not recommended, and the role of miR-10a needs to be further elucidated.