The effect of androgens on the risk of endometriosis sub-phenotypes and ovarian neoplasms: A Mendelian randomization study

Endometriosis is a complex gynecological pathology with a broad spectrum of symptoms, affecting around 10% of reproductive-aged women. Ovarian cancer (OC) is a heterogeneous disease for which we lack effective diagnostic and therapeutic strategies. The etiology and pathogenesis of both diseases remain ambiguous. Androgens in endometriosis could have a distinct role beyond serving as estrogen sources, whereas in the case of serous OC could be important in the formation of precursor lesions which ultimately lead to tumor formation. Here we performed two-sample Mendelian randomization (MR) analysis to examine the causal relationship between the androgen precursor - dehydroepiandrosterone sulphate (DHEAS), bioactive androgen - testosterone (T), androgen metabolite - androsterone sulphate, steroid hormone binding globulin (SHBG) and albumin and the risk of endometrioses of various sub-phenotypes and ovarian neoplasms across the benign-borderline-malignant spectrum. Stringent quality control procedures were followed to select eligible instrumental variables that were strongly associated with the selected exposures, sensitivity analyses were performed to assess the heterogeneities, horizontal pleiotropy, and stabilities of SNPs in endometriosis and ovarian neoplasms. We discovered an inverse association between genetically predicted levels of all androgens and risk of endometriosis, the same trend was most evident in the ovarian sub-phenotype. Total T levels were also inversely associated with peritoneal sub-phenotype of endometriosis. Likewise, T was causally associated with decreased risk of clear-cell OC, an endometriosis-associated OC subtype, and with malignant serous OC of both low- and high-grade, but with higher risk of their counterpart of low malignant potential. These findings support further investigation of androgen's action at a molecular level in ovary-associated endometriotic lesions, clear cell ovarian tumors and serous precursor lesions.

Site-Specific Regulation of Sulfatase and Aromatase Pathways for Estrogen Production in Endometriosis

Endometriosis is a highly prevalent gynecological disease characterized by lesions in different sites. Regulation of specific estrogen pathways may favor the formation of distinct microenvironments and the progression of endometriosis. However, no study has simultaneously evaluated the gene and protein regulation of the main estrogen-synthesizing enzymes in endometriosis. Thus, our goals were to study the relationship between gene and protein expression of aromatase (CYP19A1 or ARO), steroid sulfatase (STS), and hydroxysteroid 17-beta dehydrogenase (HSD17B1) in superficial (SUP), ovarian (OMA), and deep infiltrating (DIE) endometriotic lesion sites as well as in the eutopic endometrium of patients with (EE) and without (control) endometriosis in the same and large cohort of patients. The site-specific expression of these enzymes within different cells (glandular and stromal components) was also explored. The study included 108 patients surgically diagnosed with endometriosis who provided biopsies of EE and endometriotic lesions and 16 disease-free patients who collected normal endometrium tissue. Our results showed that CYP19A1 was detected in all endometriosis tissues and was in higher levels than in control. Unique patterns of the STS and HSD17B1 levels showed that they were most closely regulated in all tissues, with manifestation at greater levels in DIE compared to the other endometriotic lesion sites, OMA and SUP. Gene and protein expression of ARO, STS, and HSD17B1 occurred at different rates in endometriotic sites or EE. The distinctive levels of these estrogen-synthesizing enzymes in each endometriotic site support the hypothesis of a tissue microenvironment that can both influence and be influenced by the expression of different estrogenic pathways, locally affecting the availability of estrogen needed for maintenance and progression of endometriotic lesions.

Is intracrinology of endometriosis relevant in clinical practice? A systematic review on estrogen metabolism

Endometriosis is a chronic, multifactorial, estrogen-dependent disease. The abnormal endocrine microenvironment of endometriosis lesions is considered a main feature and multiple enzymatic pathways leading to local increased synthesis of estrogens have been identified. However, the relevance of intracrinology in clinical practice is still lacking. Medline, Embase, Scopus database were systematically searched for studies reporting on local estrogens metabolism of endometriotic lesions. The main enzymatic pathways involved in the intracrinology of endometriosis such as aromatase (CYP19A1), 17β-hydroxysteroid dehydrogenase (HSD17B) type 1, type 2 and type 5, steroid sulfatase (STS), estrogen sulfotransferase (SULT1E1) were assessed with a critical perspective on their role in disease endocrine phenotyping, drug resistance and as therapeutic targets. Overall, studies heterogeneity and missing clinical data affect the interpretation of the clinical role of these enzymes. Although the use of some drugs such as aromatase inhibitors has been proposed in clinical practice for two decades, their potential clinical value is still under investigation as well as their modality of administration. A closer look at new, more realistic drug targets is provided and discussed. Altered expression of these key enzymes in the lesions have far reaching implication in the development of new drugs aimed at decreasing local estrogenic activity with a minimal effect on gonadal function; however, given the complexity of the evaluation of the expression of the enzymes, multiple aspects still remains to be clarified.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022311329, identifier CRD42022311329.

Changing prostaglandin E2 (PGE2) signaling during lesional progression and exacerbation of endometriosis by inhibition of PGE2 receptor EP2 and EP4

Purpose

We investigated the change, if any, in prostaglandin E2 (PGE₂) signaling in endometriotic lesions of different developmental stages in mouse. In addition, we evaluated the effect of treatment of mice with induced deep endometriosis (DE) with inhibitors of PGE₂ receptor subtypes EP2 and EP4 and metformin.

Methods

Three mouse experimentations were conducted. In Experiment 1, female Balb/C mice were induced with endometriosis or DE and were serially sacrificed after induction. Experiments 2 and 3 evaluated the effect of treatment with EP2 and EP4 inhibitors and metformin, respectively, in mice with induced DE. Immunohistochemistry analysis of COX-2, EP2, and EP4, along with the extent of lesional fibrosis, was evaluated.

Results

The immunostaining of COX-2, EP2, and EP4 turned from activation to a stall as lesions progressed. Treatment with EP2/EP4 inhibitors in DE mice exacerbated endometriosis-associated hyperalgesia and promoted fibrogenesis in lesions even though it suppressed the PGE₂ signaling dose-dependently. In contrast, treatment with metformin resulted in increased PGE₂ signaling, concomitant with improved hyperalgesia, and retarded lesional fibrogenesis.

Conclusions

The PGE₂ signaling diminishes as endometriotic lesions progress. Treatment with EP2/EP4 inhibitors in DE mice exacerbates endometriosis, but metformin appears to be promising seemingly through the induction of the PGE₂ signaling.

Higher fibrotic content of endometriotic lesions is associated with diminished prostaglandin E2 signaling

Purpose

While the prevailing view holds that the prostaglandin E2 (PGE₂) signaling plays a vital role in endometriosis, PGE₂ also is known to be anti-fibrotic. We investigated the immunostaining of COX-2, EP2, and EP4, along with fibrotic content in ovarian endometrioma (OE) and deep endometriosis (DE) lesions, and in OE lesions from adolescent and adult patients. In addition, we evaluated the effect of substrate stiffness on the expression of COX-2, EP2, and EP4 in endometrial stromal cells.

Methods

Immunohistochemistry analysis of COX-2, EP2, and EP4, along with the quantification of lesional fibrosis, was conducted for OE and DE lesion samples and also OE lesion samples from adolescent and adult patients. The effect of substrate rigidity on fibroblast-to-myofibroblast transdifferentiation (FMT) and the expression of COX-2, EP2, and EP4, with or without TGF-β1 stimulation, were investigated.

Results

The immunostaining of COX-2, EP2, and EP4 was substantially reduced in endometriotic lesions as lesions became more fibrotic. Both TGF-β1 stimulation and stiff substrates induced FMT and reduced the expression of COX-2, EP2, and EP4.

Conclusions

Since fibrosis is a common feature of endometriosis, our results thus cast doubts on the use of therapeutics that suppresses the PGE₂ signaling pathway, either by inhibiting COX-2 or EP2/EP4.

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.

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.

Aromatase inhibitors for the treatment of endometriosis: a systematic review about efficacy, safety and early clinical development

INTRODUCTION

Pharmacotherapy has a key role in endometriosis treatment and management, however, a significant proportion of patients have only intermittent or limited benefits with current treatment options. Therefore, novel therapeutic approaches are necessary.

AREAS COVERED

This systematic review provides an overview of the efficacy and safety of aromatase inhibitors (AIs) as monotherapies and combination therapies for endometriosis. A systematic literature search was performed from January 1990 to April 2020 in the electronic database MEDLINE, EMBASE, The Cochrane Library, and Web of Science.

EXPERT OPINION

Based on the critical role of estrogens and the rate-limiting step in the production of the estrogens represented by the aromatase enzyme, AIs are a potential therapeutic option for women affected by endometriosis. Nevertheless, further research is needed to clarify the efficacy of AIs in this setting. Adverse effects need to be investigated to clarify the preventive role of add-back therapy. On that basis, AIs should be adopted only as second-line therapy in patients who are refractory to standard treatments in the setting of scientific research. Further studies should define best dosages, appropriate add-back therapies, administration routes, treatment length, and which patients may benefit more from AIs.

FACTORS OF ENDOMETRIAL RECEPTIVITY DOWN-REGULATION IN GENITAL ENDOMETRIOSIS

Endometriosis, or endometrioid disease, is a chronic estrogen-dependent gynecological disease caused by ectopic localization of endometrial tissue, mainly in the pelvis and ovaries. However, at the present stage of development of reproductive medicine, the classical topographic definition of endometriosis should be expanded with new significant characteristics established using the achievements of cell and molecular biology, which allowed a more detailed study of the pathogenesis of this disease. In addition, the introduction of personalized approaches to the treatment of patients with endometriosis and infertility, more attention should be paid to the search for disease predictors and the formation of risk groups with the observation of patients from puberty to menopause. In this review, we have analyzed the literature data and our own studies with an emphasis on factors and markers of decreased receptivity of eutopic endometrium in women with endometriosis, as well as pain, the manifestations of which can contribute to the exact diagnosis of external genital endometriosis.

Aromatase Inhibitors for Ovarian Stimulation in Patients with Breast Cancer

BACKGROUND

Breast cancer is the most common malignancy diagnosed in women, and its treatment has a high probability of loss of fertility. Oocyte vitrification is the most commonly used technique to preserve fertility before starting oncological treatment. Aromatase inhibitors induce hypoestrogenemia while promoting the release of gonadotropins and constitute an alternative drug for ovarian stimulation in patients with breast cancer.

OBJECTIVE

In this mini-review, we update and describe the current status of aromatase inhibitor use in controlled ovarian stimulation for oocyte vitrification in patients with breast cancer.

RESULTS

Aromatase inhibitors are commonly used in combination with gonadotropins for ovarian stimulation in patients with breast cancer who preserve their fertility through oocyte vitrification. They achieve similar ovarian responses as conventional ovarian stimulation protocols in regards to the number of oocytes, and no additional complications after their use have been reported. Furthermore, aromatase inhibitors seem to be safe not only for offspring, as no more congenital defects occur in newborns from pregnancies achieved after their use, but also for the patients, as no more malignancy recurrence or increased mortality was found in cohort studies.

CONCLUSION

Aromatase inhibitors are elective drugs for ovarian stimulation in patients with breast cancer who decide to preserve their fertility through oocyte vitrification.

Aberrant Overexpression of RNA-Editing Enzyme ADAR1 Promotes the Progression of Endometriosis

Considerable efforts have been invested to elucidate the potential mechanisms involved in the physiopathology of endometriosis. However, to date, prior research has not been conclusive. This research has examined one particular mechanism, i.e., the effect of ADAR1 on endometriosis lesions. Eutopic endometrium was collected from women with (n = 25) and without endometriosis (n = 25), respectively. The expression of ADAR1 mRNA was measured based on quantitative real-time polymerase chain reactions (RT-qPCR). Both Western blot and immunohistochemistry were performed to establish ADAR1 protein expression levels. The results indicated that ADAR1 mRNA and proteins were significantly greater in the eutopic endometrium of the women with endometriosis, compared to the women without (P < 0.05). The Cell Counting Kit-8 (CCK-8) and EdU method were conducted to examine the effect of ADAR1 on cell viability and proliferation in eutopic endometriosis cells. A transwell assay was also used to detect the role of ADAR1 in the invasion of endometrial cells. The results obtained showed that ADAR1 promoted endometrial cell viability, proliferation, and invasion (P < 0.05). This informed our conclusion that the ADAR1 gene is upregulated in endometriosis, potentially paying a pivotal role in the physiopathology of endometriosis.

An assessment of the multifactorial profile of steroid-metabolizing enzymes and steroid receptors in the eutopic endometrium during moderate to severe ovarian endometriosis

BACKGROUND

Previous studies of expression profiles of major endometrial effectors of steroid physiology in endometriosis have yielded markedly conflicting conclusions, presumably because the relative effects of type of endometriosis, fertility history and menstrual cycle phases on the measured variables were not considered. In the present study, endometrial mRNA and protein levels of several effectors of steroid biosynthesis and action in patients with stage III-IV ovarian endometriosis (OE) with known fertility and menstrual cycle histories were compared with the levels in control endometrium to test this concept.

METHODS

Endometrial samples were collected from patients without endometriosis (n = 32) or OE stages III-IV (n = 52) with known fertility and cycle histories. qRT-PCR and immunoblotting experiments were performed to measure levels of NR5A1, STAR, CYP19A1, HSD17Bs, ESRs and PGR transcripts and proteins, respectively. Tissue concentrations of steroids (P4, T, E1 and E2) were measured using ELISAs.

RESULTS

The levels of expression of aromatase and ERβ were lower (P < 0.0001) and 17β-HSD1 (P < 0.0001) and PRA (P < 0.01) were higher in OE endometrium. Lower aromatase levels and higher 17β-HSD1 levels were detected in fertile (aromatase: P < 0.05; 17β-HSD1: P < 0.0001) and infertile (aromatase: P < 0.0001; 17β-HSD1: P < 0.0001) OE endometrium than in the matched control tissues. Both proliferative (PP) and secretory (SP) phase OE samples expressed aromatase (P < 0.0001) and ERβ (PP: P < 0.001; SP: P < 0.01) at lower levels and 17β-HSD1 (P < 0.0001) and PRA (PP: P < 0.01; SP: P < 0.0001) at higher levels than matched controls. Higher 17β-HSD1 (P < 0.01) and E2 (P < 0.05) levels and a lower (P < 0.01) PRB/PRA ratio was observed in infertile secretory phase OE endometrium than in control.

CONCLUSIONS

We report that dysregulated expression of 17β-HSD1 and PGR resulting in hyperestrogenism and progesterone resistance during the secretory phase of the menstrual cycle, rather than an anomaly in aromatase expression, was the hallmark of eutopic endometrium from infertile OE patients. Furthermore, the results provide proof of concept that the fertility and menstrual cycle histories exerted relatively different effects on steroid physiology in the endometrium from OE patients compared with the control subjects.

Aldo-keto reductase 1C3-Assessment as a new target for the treatment of endometriosis

Endometriosis is a common gynecological disorder, which is treated surgically and/ or pharmacologically with an unmet clinical need for new therapeutics. A completed phase I trial and a recent phase II trial that investigated the steroidal aldo-keto reductase 1C3 (AKR1C3) inhibitor BAY1128688 in endometriosis patients prompted this critical assessment on the role of AKR1C3 in endometriosis. This review includes an introduction to endometriosis with emphasis on the roles of prostaglandins and progesterone in its pathophysiology. This is followed by an overview of the major enzymatic activities and physiological functions of AKR1C3 and of the data published to date on the expression of AKR1C3 in endometriosis at the mRNA and protein levels. The review concludes with the rationale for using AKR1C3 inhibitors, a discussion of the effects of AKR1C3 inhibition on the pathophysiology of endometriosis and a brief overview of other drugs under clinical investigation for this indication.

Hormonal Replacement Therapy in Menopausal Women with History of Endometriosis: A Review of Literature

Hormonal replacement therapy (HRT) is effective in treating the symptoms of menopause. Endometriosis is defined as the presence of functional endometrial tissue outside the uterine cavity with a tendency towards invasion and infiltration. Being an estrogen-dependent disease, it tends to regress after menopause. Nevertheless, it affects up to 2.2% of postmenopausal women. Conclusive data are not available in the literature on the appropriateness of HRT in women with endometriosis or a past history of the disease. The hypothesis that exogenous estrogen stimulation could reactivate endometriotic foci has been proposed. The aim of this state-of-the-art review was to revise the current literature about endometriosis in perimenopause and menopause and to investigate the possible role of HRT in this setting of patients. An electronic databases search (MEDLINE, Scopus, ClinicalTrials.gov, EMBASE, Sciencedirect, the Cochrane Library at the CENTRAL Register of Controlled Trials, Scielo) was performed, with the date range of from each database’s inception until May 2019. All of the studies evaluating the impact of different HRT regimens in patients with a history of endometriosis were selected. 45 articles were found: one Cochrane systematic review, one systematic review, five narrative reviews, two clinical trials, two retrospective cohort studies, 34 case reports and case series. Some authors reported an increased risk of malignant transformation of endometriomas after menopause in patients assuming HRT with unopposed estrogen. Low-quality evidence suggests that HRT can be prescribed to symptomatic women with a history of endometriosis, especially in young patients with premature menopause. Continuous or cyclic combined preparations or tibolone are the best choices. HRT improves quality of life in symptomatic post-menopausal women, who should not be denied the replacement therapy only due to their history of endometriosis. Based on low-grade literature evidence, we recommend to prescribe combined HRT schemes; tibolone could be considered.

Postmenopausal endometriosis, where are we now?

PURPOSE OF REVIEW

Postmenopausal endometriosis is a gynecologic disease, affecting 2-5% of postmenopausal woman. Current literature assessing the prevalence, pathogenesis, and treatment of this uncommon condition is limited, stressing the necessity for future research. This review examines the current literature on postmenopausal endometriosis to help inform clinical decision-making and point to novel approaches for treatment and management.

RECENT FINDINGS

Although one unifying theory to explain the pathogenesis of endometriotic lesions has not been elucidated, estrogen dependence is central to the pathophysiological process. The total quantity of estrogen production is mediated by multiple enzymes in complex pathways. Recent studies have confirmed the presence of these necessary enzymes in endometriotic lesions thereby suggesting a local source of estrogen and a likely pathogenic contributor. More research is needed to fully elucidate the mechanism of local estrogen biosynthesis; however, the current data provide possible explanations for the presence of postmenopausal endometriosis in an otherwise systemically hypoestrogenic environment.

SUMMARY

All suspected endometriosis lesions should be surgically excised for optimization of treatment and prevention of malignant transformation. If hormone replacement therapy is initiated, combined estrogen and progestin is recommended, even in the setting of previous hysterectomy, given the risk of disease reactivation and malignant transformation of endometriotic lesions. Further research is needed to understand the true prevalence, cause, and progression in this patient demographic. Histologic studies evaluating tissue lesions and peritoneal fluid for estrogen receptors, estrogen metabolizing enzymes, immune cells, and nerve fibers will aide in clinical management and treatment planning.

Intracrine Regulation of Estrogen and Other Sex Steroid Levels in Endometrium and Non-gynecological Tissues; Pathology, Physiology, and Drug Discovery

Our understanding of the intracrine (or local) regulation of estrogen and other steroid synthesis and degradation expanded in the last decades, also thanks to recent technological advances in chromatography mass-spectrometry. Estrogen responsive tissues and organs are not passive receivers of the pool of steroids present in the blood but they can actively modify the intra-tissue steroid concentrations. This allows fine-tuning the exposure of responsive tissues and organs to estrogens and other steroids in order to best respond to the physiological needs of each specific organ. Deviations in such intracrine control can lead to unbalanced steroid hormone exposure and disturbances. Through a systematic bibliographic search on the expression of the intracrine enzymes in various tissues, this review gives an up-to-date view of the intracrine estrogen metabolisms, and to a lesser extent that of progestogens and androgens, in the lower female genital tract, including the physiological control of endometrial functions, receptivity, menopausal status and related pathological conditions. An overview of the intracrine regulation in extra gynecological tissues such as the lungs, gastrointestinal tract, brain, colon and bone is given. Current therapeutic approaches aimed at interfering with these metabolisms and future perspectives are discussed.

SULFATION PATHWAYS: Contribution of intracrine oestrogens to the aetiology of endometriosis

Endometriosis is an incurable hormone-dependent inflammatory disease that causes chronic pelvic pain and infertility characterized by implantation and growth of endometrial tissue outside the uterine cavity. Symptoms have a major impact on the quality of life of patients resulting in socioeconomic, physical and psychological burdens. Although the immune system and environmental factors may play a role in the aetiology of endometriosis, oestrogen dependency is still considered a hallmark of the disorder. The impact of oestrogens such as oestrone and particularly, oestradiol, on the endometrium or endometriotic lesions may be mediated by steroids originating from ovarian steroidogenesis or local intra-tissue production (intracrinology) dependent upon the expression and activity of enzymes that regulate oestrogen biosynthesis and metabolism. Two key pathways have been implicated: while there is contradictory data on the participation of the aromatase enzyme (encoded by CYP19A1), there is increasing evidence that the steroid sulphatase pathway plays a role in both the aetiology and pathology of endometriosis. In this review, we consider the evidence related to the pathways leading to oestrogen accumulation in endometriotic lesions and how this might inform the development of new therapeutic strategies to treat endometriosis without causing the undesirable side effects of current regimes that suppress ovarian hormone production.

Identifying stably expressed housekeeping genes in the endometrium of fertile women, women with recurrent implantation failure and recurrent miscarriages

Housekeeping genes (HKG) are presumed to be constitutively expressed throughout tissue types but recent studies have shown they vary with pathophysiology. Often, validation of appropriate HKG is not made. There is no consensus on which HKGs are most stably expressed in endometrial tissue so this study aimed to identify the most stable HKG in the endometrium of women with recurrent implantation failure (RIF) and recurrent miscarriages (RM). Inclusion criteria were women between 25-45 years (n = 45) suffering recurrent miscarriage (RM), recurrent implantation failure (RIF) or fertile controls. Endometrial biopsies were taken and total RNA extraction, cDNA synthesis and PCR was performed using 10 candidate HKG. The genes were arranged in terms of stability and normalisation was determined. Several HKGs not previously tested in endometrial samples were found to be more stable than those previously identified as the most stable. Of these, the 5 most stable HKG (in order of stability) were Prdm4 (PR domain 4) > Ube4a (Ubiquitin-Conjugating Enzyme 4a) > Enox2 (Ecto-NOX Disulfide-Thiol Exchanger 2) > Ube2d2 (Ubiquitin-conjugating enzyme E2D 2) > Actb (Actin beta). We therefore recommend using at least four of the aforementioned HKG for normalisation of endometrial tissues taken from patients with RM and RIF.

Characteristics of Women with Recurrent Endometriosis Pain after Laparoscopy and Levonorgestrel Intrauterine Device Placement

Introduction

The levonorgestrel (LNG)-intrauterine device (IUD) is effective for many, but not all, women with endometriosis in managing pelvic pain. The aim of this study was to explore the characteristics associated with recurrent endometriosis pain within 12 months after operative laparoscopy and LNG-IUD placement.

Methods

This retrospective case series was performed at a university-affiliated infertility and reproductive surgery practice and included women who underwent operative laparoscopy and LNG-IUD placement by a single surgeon from January 1, 2012 to October 7, 2015 (n = 32). Within 12 months post-operatively, the primary surgeon assessed pain reported by the patient and prescribed adjunctive oral hormonal therapy for recurrent pain symptoms. Data were collected using the patients’ electronic medical records. The main outcome was the presence of recurrent endometriosis pain within 12 months after operative laparoscopy with LNG-IUD placement.

Results

Of the 32 women who underwent laparoscopy and LNG-IUD placement, 26 presented for follow-up (81.2%) within 12 months, 15 of whom (57.7%) reported recurrent pain. The odds of poor pain control were higher among the women who were obese, among those who had undergone prior laparoscopy, and among those with a history of asthma, depression, or headaches.

Conclusions

The optimal management of endometriosis-related pain is highly patient-specific, and poor response to LNG-IUD may be associated with having had a prior laparoscopy, obesity, and certain medical comorbidities.

Endometriosis after menopause: physiopathology and management of an uncommon condition

Endometriosis is a hormone-dependent inflammatory disease that is usually characterized by infertility and pain symptoms. This disease mainly occurs during the reproductive years and is rarely diagnosed after menopause. We discuss the physiopathology of this condition after menopause as well as treatment options and the risk of malignant transformation. Occurrence or progression of postmenopausal endometriosis lesions could be related to extra-ovarian production of estrogen by endometriosis lesions and adipose tissue, which becomes the major estrogen-producing tissue after menopause. Postmenopausal women with symptomatic endometriosis should be managed surgically because of the risk of malignancy; medical treatments can be used in cases of pain recurrence after surgery. Aromatase inhibitors act by decreasing extra-ovarian estrogen production and by blocking the feed-forward stimulation loop between inflammation and aromatase within endometriosis lesions. The evidence is currently insufficient to support a conclusion about the optimal hormone replacement therapy for women with endometriosis. The question of malignant transformation of endometriosis in response to hormone replacement therapy in women with a history of endometriosis remains unanswered and needs a long-term follow-up study to evaluate the risk of an adverse outcome. Further studies should be performed to determine the optimal management of menopausal women with endometriosis.

Activin A Stimulates Aromatase via the ALK4-Smad Pathway in Endometriosis

Endometriosis is an estrogen-dependent disease. We previously found that the expression of Activin A was upregulated in the peritoneal fluid of patients with endometriosis. The results of the present study indicated that Activin A induced estradiol secretion and P450arom expression in endometrial stromal cells (ESCs) derived from endometriosis patients. The mechanism of estrogenic synthesis was regulated by the Activin-Smad pathway in endometrial lesions. The data showed that the effect of Activin A on ESCs was partially abrogated by pretreatment with an inhibitor of ALK4 (the type I receptor, ActRIB) and Smad4-siRNA. Cumulatively, these data suggest that Activin A promotes the secretion of estradiol from ESCs by increasing the expression of P450arom via the ALK4-Smad pathway. These findings indicate the ALK4-Smad pathway may promote ectopic lesion survival and development.

Adenomyosis: a systematic review of medical treatment

Adenomyosis is a heterogeneous gynaecologic condition with a range of clinical presentations, the most common being heavy menstrual bleeding and dysmenorrhoea; however, patients can also be asymptomatic. Several studies support the theory that adenomyosis results from invasion of the endometrium into the myometrium, causing alterations in the junctional zone. These changes are commonly seen on imaging studies, such as transvaginal ultrasound and magnetic resonance imaging. The aim of this review is to discuss the medical approach to the management of adenomyosis symptoms, including pain and abnormal uterine bleeding. The standard treatment of adenomyosis is hysterectomy, but there is no medical therapy to treat the symptoms of adenomyosis while still allowing patients to conceive. Medical therapies using suppressive hormonal treatments, such as continuous use of oral contraceptive pills, high-dose progestins, selective oestrogen receptor modulators, selective progesterone receptor modulators, the levonorgestrel-releasing intrauterine device, aromatase inhibitors, danazol, and gonadotrophin receptor hormone agonists can temporarily induce regression of adenomyosis and improve the symptoms.

Endometriosis: alternative methods of medical treatment

Endometriosis is an inflammatory estrogen-dependent disease defined by the presence of endometrial glands and stroma at extrauterine sites. The main purpose of endometriosis management is alleviating pain associated to the disease. This can be achieved surgically or medically, although in most women a combination of both treatments is required. Long-term medical treatment is usually needed in most women. Unfortunately, in most cases, pain symptoms recur between 6 months and 12 months once treatment is stopped. The authors conducted a literature search for English original articles, related to new medical treatments of endometriosis in humans, including articles published in PubMed, Medline, and the Cochrane Library. Keywords included "endometriosis" matched with "medical treatment", "new treatment", "GnRH antagonists", "Aromatase inhibitors", "selective progesterone receptor modulators", "anti-TNF α", and "anti-angiogenic factors". Hormonal treatments currently available are effective in the relief of pain associated to endometriosis. Among new hormonal drugs, association to aromatase inhibitors could be effective in the treatment of women who do not respond to conventional therapies. GnRH antagonists are expected to be as effective as GnRH agonists, but with easier administration (oral). There is a need to find effective treatments that do not block the ovarian function. For this purpose, antiangiogenic factors could be important components of endometriosis therapy in the future. Upcoming researches and controlled clinical trials should focus on these drugs.

Metformin Suppresses Prostaglandin E2-Induced Cytochrome P450 Aromatase Gene Expression and Activity via Stimulation of AMP-Activated Protein Kinase in Human Endometriotic Stromal Cells

BACKGROUND

Cytochrome P450 aromatase (encoded by the CYP19A1/aromatase gene) plays a critical physiologic role in endometriosis. Metformin is known to suppress prostaglandin E2 (PGE2)-induced CYP19A1 messenger RNA (mRNA) expression in human endometriotic stromal cells (ESCs). However, the possible mechanism behind this suppression remains to be determined.

METHODS

In this study, ESCs were cultured with metformin, PGE2, and adenosine monophosphate (AMP)-activated protein kinase (AMPK) inhibitors. Expression of CYP19A1 mRNA and aromatase activity were measured by quantitative polymerase chain reaction and aromatase activity assay, respectively. The binding of the cyclic AMP response element-binding (CREB) protein to CYP19A1 promoter II (PII) was assessed by chromatin immunoprecipitation assay.

RESULTS

We demonstrated that metformin downregulated the expression of aromatase mRNA (32%) and activity (25%) stimulated by PGE2 (4.18-fold and 2.14-fold) in ESCs via stimulation of AMPK. Following PGE2 treatment, there was a marked increase in CREB binding to aromatase PII, while metformin attenuated the above-mentioned stimulation by 67%.

CONCLUSION

Metformin could inhibit PGE2-induced CYP19A1 mRNA expression and aromatase activity via AMPK activation and inhibition of CREB to CYP19A1 PII in human ESCs. The results of the present study suggest that metformin may have unique therapeutic potential as an antiendometriotic drug in the future.

Estradiol and tamoxifen enhance invasion of endometrial stromal cells in a three-dimensional coculture model of adenomyosis

OBJECTIVE

To examine the effect of estradiol alone or with progesterone and tamoxifen on the depth of invasion of endometrial stromal cells from women with and without adenomyosis in a three-dimensional (3D) coculture model that includes myocytes.

DESIGN

Case-controlled, blinded comparison.

SETTING

Medical school department.

PATIENT(S)

Premenopausal women with and without uterine adenomyosis.

INTERVENTION(S)

Human endometrial stromal and myometrial cells grown in a 3D coculture with crossover between cells from uteri with and without adenomyosis; cocultures treated with tamoxifen, estradiol alone, or estradiol with progesterone.

MAIN OUTCOME MEASURE(S)

Depth of stromal cell invasion into a collagen matrix.

RESULT(S)

The depth of invasion for adenomyotic stromal cells was statistically significantly higher than for the control stromal cells, whether grown on plain collagen, on collagen containing control or adenomyotic muscle cells. The addition of estradiol or tamoxifen, but not the estradiol and progesterone combination, increased the depth of invasion of both adenomyotic stromal cells and control stromal cells in all cell combinations. When grown on plain collagen, the depth of invasion for control stromal cells and adenomyotic stromal cells increased by 126% and 93% with the use of tamoxifen, and by 71% and 50%, with the use of estradiol.

CONCLUSION(S)

Both estradiol and tamoxifen enhance stromal cell invasion, but the greater depth of invasion of adenomyotic stromal cells and the enhancing effect of adenomyotic muscle were maintained under all experimental conditions, suggesting an inherent predisposition in affected women.

Role of inflammation and aromatase expression in the eutopic endometrium and its relationship with the development of endometriosis

Epigenetic changes favoring the transcription of the aromatase gene in the endometrium allow endometrial cells to survive in ectopic locations by producing estrogens that spare them from destruction through activated macrophages. Local estrogen production hastens prostaglandin synthesis by stimulating COX-2 activity, thus creating a self-perpetuating sequence of augmented estrogen formation and enhanced inflammation. Repetitive retrograde menstruation reintroduces aromatase-positive endometrial cells endowed with the capacity to implant and invade the peritoneum. In order to control endometriosis, an effective medication must inhibit aromatase, block COX-2, decrease fibrosis and induce amenorrhea. Within this framework, progestins, either alone or in the form of oral contraceptives, appear as first-line treatment for endometriosis owing to their capacity to block enzymes such as aromatase and COX-2.

An update on the pharmacological management of endometriosis

INTRODUCTION

Endometriosis is a common disease that causes pain symptoms and/or infertility in women in their reproductive years. The disease is characterised by the presence of endometrium-like tissue - glands and stroma - outside the uterine cavity. Different treatment options exist for endometriosis including medical and surgical treatments or a combination of the two approaches. The most commonly used medications are non-steroidal anti-inflammatory drugs, GnRH agonists, androgen derivatives such as danazol, combined oral contraceptive pills, progestogens and more recently the levonorgestrel intrauterine system.

AREAS COVERED

The authors review current medical treatments used for symptomatic endometriosis and also discuss new treatment approaches. The authors conducted a literature search for randomised controlled trials related to medical treatments of endometriosis in humans, searched the Cochrane library for reviews and also searched for registered trials that have not yet been published on ClinicalTrials.gov.

EXPERT OPINION

The medical treatment of endometriosis is effective at treating pain and preventing recurrence of disease after surgery. Remarkably, the oral contraceptive pill taken continuously is as effective as GnRH-a, while causing far less side-effects. Conversely, no treatment currently exists for enhancing fecundity in women whose infertility is associated with endometriosis. As all existing therapies of endometriosis are contraceptive, great efforts should be targeted at researching novel products that reduce the disease expression without shuttering ovulation.

Effects of progestins on local estradiol biosynthesis and action in the Z-12 endometriotic epithelial cell line

Endometriosis is a common estrogen-dependent gynecological disease. In patients with endometriosis estradiol can be synthesized locally in the endometriotic lesions from inactive precursors of adrenal or ovarian origin, via the aromatase pathway. These increased estradiol levels stimulate proliferation of endometriotic tissue. The progestins have been used in the therapy of endometriosis for more than 40 years but their pharmacological action is still not understood in detail. In the present study we therefore aimed to evaluate the effects of three progestins most commonly used in the therapy of endometriosis; medroxyprogesterone acetate, dydrogesterone and dienogest on expression of all genes encoding enzymes of the aromatase pathway and estrogen receptors in the Z-12 model epithelial cell line of peritoneal endometriosis, by qPCR and Western blotting. Our results show that application of medroxyprogestrone acetate, dydrogesterone and dienogest significantly decreases HSD17B1 and CYP19A1 expression and significantly increases HSD17B2 expression. Dydrogesterone and dienogest also significantly suppress ESR1 and ESR2 transcription, whereas medroxyprogestrone acetate and dydrogesterone significantly reduce mRNA levels of GPER. Our results thus suggest that in peritoneal endometriosis the beneficial effects of these progestins can be explained by lower HSD17B1 and higher HSD17B2 mRNA and protein levels, which lead to reduced local E2 biosynthesis. Although progestins significantly decrease CYP19A1 mRNA levels, the protein itself was not detectable by Western blotting. As progestins down-regulate expression of ESR1, ESR2 and GPER, they might also prevent E2-mediated proliferation.

Genome-wide expressions in autologous eutopic and ectopic endometrium of fertile women with endometriosis

BACKGROUND

In order to obtain a lead of the pathophysiology of endometriosis, genome-wide expressional analyses of eutopic and ectopic endometrium have earlier been reported, however, the effects of stages of severity and phases of menstrual cycle on expressional profiles have not been examined. The effect of genetic heterogeneity and fertility history on transcriptional activity was also not considered. In the present study, a genome-wide expression analysis of autologous, paired eutopic and ectopic endometrial samples obtained from fertile women (n=18) suffering from moderate (stage 3; n=8) or severe (stage 4; n=10) ovarian endometriosis during proliferative (n=13) and secretory (n=5) phases of menstrual cycle was performed.

METHODS

Individual pure RNA samples were subjected to Agilent's Whole Human Genome 44K microarray experiments. Microarray data were validated (P<0.01) by estimating transcript copy numbers by performing real time RT-PCR of seven (7) arbitrarily selected genes in all samples. The data obtained were subjected to differential expression (DE) and differential co-expression (DC) analyses followed by networks and enrichment analysis, and gene set enrichment analysis (GSEA). The reproducibility of prediction based on GSEA implementation of DC results was assessed by examining the relative expressions of twenty eight (28) selected genes in RNA samples obtained from fresh pool of eutopic and ectopic samples from confirmed ovarian endometriosis patients with stages 3 and 4 (n=4/each) during proliferative and secretory (n=4/each) phases.

RESULTS

Higher clustering effect of pairing (cluster distance, cd=0.1) in samples from same individuals on expressional arrays among eutopic and ectopic samples was observed as compared to that of clinical stages of severity (cd=0.5) and phases of menstrual cycle (cd=0.6). Post hoc analysis revealed anomaly in the expressional profiles of several genes associated with immunological, neuracrine and endocrine functions and gynecological cancers however with no overt oncogenic potential in endometriotic tissue. Dys-regulation of three (CLOCK, ESR1, and MYC) major transcription factors appeared to be significant causative factors in the pathogenesis of ovarian endometriosis. A novel cohort of twenty-eight (28) genes representing potential marker for ovarian endometriosis in fertile women was discovered.

CONCLUSIONS

Dysfunctional expression of immuno-neuro-endocrine behaviour in endometrium appeared critical to endometriosis. Although no overt oncogenic potential was evident, several genes associated with gynecological cancers were observed to be high in the expressional profiles in endometriotic tissue.

Estrogen biosynthesis and signaling in endometriosis

Endometriosis is an estrogen-dependent gynecological disease where endometrium-like tissue grows outside uterine cavity. Endometriotic cell proliferation is stimulated by estrogens acting predominantly via their nuclear receptors. Estrogen receptors (ESR1, ESR2) are ligand activated transcription factors whose activation is dependent on the cell-specific dynamic expression of the receptors, on the interacting proteins and on the ligand availability. The different types of endometriotic lesions, peritoneal, deep, and ovarian endometriosis, may respond to estrogens differentially due to differences in the expression of the receptors and interacting proteins, and due to potential differences in the ligand availability regulated by the local estrogen synthesis. This review summarizes the current knowledge of estrogen synthesizing enzymes and estrogen receptors in different types of endometriosis lesions. Further studies are still needed to define the possible differences in steroid metabolism in different types of endometriotic lesions.

Effect of letrozole on estradiol production and P450 aromatase messenger RNA expression of cultured luteinized granulosa cells from women with and without endometriosis

OBJECTIVE

To compare the estradiol production and P450 aromatase messenger RNA (mRNA) expression of cultured luteinized granulosa cells and the effect of letrozole on these parameters between women with and without endometriosis.

DESIGN

In vitro assays.

SETTING

Reproductive medical center.

PATIENT(S)

Patients undergoing in vitro fertilization (IVF): 23 patients with endometriosis and 19 controls without endometriosis.

INTERVENTION(S)

Luteinized granulosa cells examined for estradiol levels and P450 aromatase mRNA expression in conditioned media at different letrozole concentrations of 0.0, 0.1, 1.0, and 10.0 μmol/L.

MAIN OUTCOME MEASURE(S)

Estradiol levels of the conditioned medium measured with an enzyme-linked immunosorbent assay (ELISA) kit and P450 aromatase mRNA expression determined by quantitative reverse transcription-polymerase chain reaction (QT RT-PCR).

RESULT(S)

The estradiol concentration of the conditioned media and P450 aromatase mRNA expression in the endometriosis group were statistically significantly lower than that of the control group, irrespective of letrozole concentrations. A statistically significant reduction of these two parameters was observed in both endometriosis and control groups at letrozole concentrations of 1 μmol/L and 10 μmol/L, but there were no statistically significant differences between letrozole concentrations of 1 μmol/L and 10 μmol/L. The number of high-quality embryos in the endometriosis group was statistically significantly lower than that of the control group.

CONCLUSION(S)

Lower estradiol production and P450 aromatase mRNA expression of cultured granulosa cells were found in women with endometriosis. Letrozole in the conditioned media further reduced these parameters.

New treatment strategies and emerging drugs in endometriosis

Introduction: Endometriosis, histologically defined as the presence of endometrium-like tissue - glands and stroma - that develops outside of the uterine cavity, is still an enigmatic disease responsible for pelvic pain and infertility. The current treatments of endometriosis are surgery and hormonal therapies that act by suppressing ovulation and/or directly on steroid receptors located in endometriotic lesions. Areas covered: New hormonal and non-hormonal therapies are being developed for the treatment of endometriosis-related pain. The authors review the state of advancement and the results of novel treatments studied in registered trials ( www.ClinicalTrials.gov ). Cellular signaling pathways activated in endometriotic cells, which constitute potential targets for future treatments, are also described. Expert opinion: Therapeutic research efforts should focus on identifying and testing substances capable of acting locally on the lesions themselves, without interfering with ovulation, in order to be efficacious on both pain symptoms and infertility.

Genetic variation in the sex hormone metabolic pathway and endometriosis risk: an evaluation of candidate genes

OBJECTIVE

To evaluate the relationship between common genetic variation in genes involved in the biosynthesis and signaling of estrogen and progesterone and endometriosis risk.

DESIGN

Genetic polymorphism analysis.

SETTING

Population-based case-control study conducted in Group Health Cooperative enrollees in western Washington.

PATIENT(S)

Women with newly diagnosed, surgically confirmed endometriosis between 1996 and 2001 (n = 256) and age- and reference year-matched female control subjects without a history of endometriosis (n = 567).

INTERVENTIONS(S)

None.

MAIN OUTCOME MEASURE(S)

We evaluated the relationship between common genetic variation and endometriosis risk, using gene-based tests and single-variant analysis of genetic polymorphisms in ESR1, ESR2, PGR, CYP17A1, CYP19A1, HSD17B1, HSD17B2, CYP1A1, CYP1A2, COMT, and GSTM1.

RESULT(S)

The most consistent gene-based association with endometriosis risk was for CYP19A1. We did not find evidence for consistent significant associations between previously reported candidate SNPs in sex hormone-related genes and endometriosis risk.

CONCLUSION(S)

In summary, we report increased endometriosis risk with CYP19A1 gene-based tests; replication of the association between endometriosis and this gene or gene region is necessary in a larger study population.

Pyrrolidine dithiocarbamate attenuates nuclear factor-ĸB activation, cyclooxygenase-2 expression and prostaglandin E2 production in human endometriotic epithelial cells

BACKGROUND

The nuclear factor-κB (NF-κB) pathway activates many of the target genes that are critical to the initiation and establishment of endometriosis. We sought to examine the potential application of pyrrolidine dithiocarbamate (PDTC), a potent NF-κB inhibitor, in the treatment of endometriosis.

METHODS

The phosphorylation of IκB, expression of nuclear p65 protein and NF-κB DNA binding in endometriotic epithelial cells (EECs), endometriotic eutopic epithelial cells (EuECs) and normal epithelial cells (NECs) were detected by Western blot analysis and electrophoretic mobility shift assay. Cyclooxgenase-2 (COX-2) gene and protein expressions in EECs were measured by RT-PCR and Western blot analysis. Prostaglandin E(2) (PGE(2)) production of EECs was measured by ELISA.

RESULTS

PDTC in the absence or presence of tumor necrosing factor-α (TNF-α) showed stronger inhibitory effects on IκB phosphorylation, expression of nuclear p65 protein and NF-κB DNA-binding activity in EECs than in EuECs or NECs. Pretreatment of EECs with PDTC resulted in a dose-dependent reduction in the TNF-α-induced expressions of COX-2 at gene and protein levels, as well as a reduction of PGE(2) synthesis.

CONCLUSION

PDTC may represent a novel therapeutic strategy for treatment of endometriosis.

How can macroscopically normal peritoneum contribute to the pathogenesis of endometriosis?

This study indicates that the immunobiology of macroscopically normal peritoneum is relevant to understand the pathogenesis of endometriosis. Peritoneal interleukin 6, interleukin 12, and ferritin were differentially expressed in women with and without endometriosis.

Novel estrogen-related genes and potential biomarkers of ovarian endometriosis identified by differential expression analysis

In the search for novel biomarkers of endometriosis, we selected 152 genes from the GeneLogic database based on results of genome-wide expression analysis of ovarian endometriosis, plus 20 genes related to estrogen metabolism and action. We then performed low-density array analysis of these 172 genes on 11 ovarian endometriosis samples and 9 control endometrium samples. Principal component analysis of the gene expression levels showed clear separation between the endometriosis and control groups. We identified 78 genes as differentially expressed. Based on Ingenuity pathway analysis, these differentially expressed genes were arranged into groups according to biological function. These analyses revealed that 32 differentially expressed genes are estrogen related, 23 of which have not been reported previously in connection with endometriosis. Functional annotation showed that 25 and 22 genes are associated with the biological terms "secreted" and "extracellular region", respectively. Differential expression of 4 out of 5 genes related to estrogen metabolism and action (ESR1, ESR2, PGR and BGN) was also confirmed by immunohistochemistry. Our study thus reveals differential expression of several genes that have not previously been associated with endometriosis and that encode potential novel biomarkers and drug targets.

The emerging use of aromatase inhibitors for endometriosis treatment

Endometriosis is defined as the growth of endometrial tissue outside of the uterine cavity. The disease occurs primarily in women of reproductive age but recurrent endometriosis is also detected in post-menopausal women. Regardless of age, endometriosis is associated with pain and reduces the quality of life for millions of women world-wide. Conventional therapies focus on reducing systemic levels of estrogen which results in cessation of endometriotic implant growth and pain symptoms associated with the disease. However, these treatments are not effective in all women and are not without side effects. Based upon the discovery that endometriotic tissue over-expresses aromatase, an enzyme critical for estrogen production, emphasis has been placed upon the use of aromatase inhibitors for the treatment of endometriosis and its associated symptoms. This article will review the rationale behind the use of aromatase inhibitors in treating endometriosis and summarize those studies which have evaluated the use of aromatase inhibitors in the treatment of endometriosis and its associated symptoms.

Use of aromatase inhibitors to treat endometriosis-related pain symptoms: a systematic review

This systematic review aims to assess the efficacy of aromatase inhibitors (AIs) in treating pain symptoms caused by endometriosis. A comprehensive literature search was conducted to identify all the published studies evaluating the efficacy of type II nonsteroidal aromatase inhibitors (anastrozole and letrozole) in treating endometriosis-related pain symptoms. The MEDLINE, EMBASE, PubMed, and SCOPUS databases and the Cochrane System Reviews were searched up to October 2010. This review comprises of the results of 10 publications fitting the inclusion criteria; these studies included a total of 251 women. Five studies were prospective non-comparative, four were randomized controlled trials (RCTs) and one was a prospective patient preference trial. Seven studies examined the efficacy of AIs in improving endometriosis-related pain symptoms, whilst three RCTs investigated the use of AIs as post-operative therapy in preventing the recurrence of pain symptoms after surgery for endometriosis. All the observational studies demonstrated that AIs combined with either progestogens or oral contraceptive pill reduce the severity of pain symptoms and improve quality of life. One patient preference study demonstrated that letrozole combined with norethisterone acetate is more effective in reducing pain and deep dyspareunia than norethisterone acetate alone. However, letrozole causes a higher incidence of adverse effects and does not improve patients' satisfaction or influence recurrence of symptoms after discontinuation of treatment. A RCT showed that combining letrozole with norethisterone acetate causes a lower incidence of adverse effects and lower discontinuation rate than combining letrozole with triptorelin. Two RCTs demonstrated that, after surgical treatment of endometriosis, the administration of AIs combined with gonadotropin releasing hormone analogue for 6 months reduces the risk of endometriosis recurrence when compared with gonadotropin releasing hormone analogue alone. In conclusion, AIs effectively reduce the severity of endometriosis-related pain symptoms. Since endometriosis is a chronic disease, future investigations should clarify whether the long-term administration of AIs is superior to currently available endocrine therapies in terms of improvement of pain, adverse effects and patient satisfaction.

Endometriotic implants regress in rat models treated with puerarin by decreasing estradiol level

Phytoestrogens, which have a weak estrogenic effect, bind to estrogen receptors (ERs), thereby competing with estradiol, have an antiestrogenic effect on women of reproductive age with high estrogenic level. Herein, we examined the ability of the phytoestrogen Puerarin to treat endometriosis in rat models of endometriosis. In total, 75 adult, mature female Sprague-Dawley rats in which endometriotic implants were successfully induced by transplanting autologous endometrial tissue to ectopic sites were used in this study. Oral gavage of Puerarin (at doses of 600, 200, or 60 mg/kg per day) or Danazol (80 mg/kg per day) started 4 weeks after implantation. Control model rats received vehicle alone. After administration for 4 weeks, the weight of the ectopic implants, estradiol concentration, as well as ER-α and Aromatase P450 (P450arom) expression in different groups of rat tissues were evaluated after treatment. The endometriotic tissue weight and serum estrogen levels were significantly lower in high, medium, low dose of Puerarin and Danazol treatment groups than that in control group (P < .05 or P < .01). Low-dose Puerarin inhibited P450arom expression and significantly reduced estrogen levels in endometriotic tissue (P < .01). Three doses of Puerarin had no adverse effects on liver, kidney, and ovary, whereas high-dose Puerarin administration caused thinner bone trabecula with distortion and breakage and Danazol administration caused mild or moderate hepatic cell damage. These data demonstrate that Puerarin was able to effectively suppress the growth and development of ectopic endometrium in the rat endometriosis model, even at low doses, suggesting it may be an effective treatment for endometriosis.