Endometrial aromatase mRNA as a possible screening tool for advanced endometriosis and adenomyosis

A View on Uterine Leiomyoma Genesis through the Prism of Genetic, Epigenetic and Cellular Heterogeneity

Uterine leiomyomas (ULs), frequent benign tumours of the female reproductive tract, are associated with a range of symptoms and significant morbidity. Despite extensive research, there is no consensus on essential points of UL initiation and development. The main reason for this is a pronounced inter- and intratumoral heterogeneity resulting from diverse and complicated mechanisms underlying UL pathobiology. In this review, we comprehensively analyse risk and protective factors for UL development, UL cellular composition, hormonal and paracrine signalling, epigenetic regulation and genetic abnormalities. We conclude the need to carefully update the concept of UL genesis in light of the current data. Staying within the framework of the existing hypotheses, we introduce a possible timeline for UL development and the associated key events—from potential prerequisites to the beginning of UL formation and the onset of driver and passenger changes.

Overexpression of Human Estrogen Biosynthetic Enzyme Hydroxysteroid (17beta) Dehydrogenase Type 1 Induces Adenomyosis-like Phenotype in Transgenic Mice

Hydroxysteroid (17beta) dehydrogenase type 1 (HSD17B1) is an enzyme that converts estrone to estradiol, while adenomyosis is an estrogen-dependent disease with poorly understood pathophysiology. In the present study, we show that mice universally over-expressing human estrogen biosynthetic enzyme HSD17B1 (HSD17B1TG mice) present with adenomyosis phenotype, characterized by histological and molecular evaluation. The first adenomyotic changes with endometrial glands partially or fully infiltrated into the myometrium appeared at the age of 5.5 months in HSD17B1TG females and became more prominent with increasing age. Preceding the phenotype, increased myometrial smooth muscle actin positivity and increased amount of glandular myofibroblast cells were observed in HSD17B1TG uteri. This was accompanied by transcriptomic upregulation of inflammatory and estrogen signaling pathways. Further, the genes upregulated in the HSD17B1TG uterus were enriched with genes previously observed to be induced in the human adenomyotic uterus, including several genes of the NFKB pathway. A 6-week-long HSD17B1 inhibitor treatment reduced the occurrence of the adenomyotic changes by 5-fold, whereas no effect was observed in the vehicle-treated HSD17B1TG mice, suggesting that estrogen is the main upstream regulator of adenomyosis-induced uterine signaling pathways. HSD17B1 is considered as a promising drug target to inhibit estrogen-dependent growth of endometrial disorders. The present data indicate that HSD17B1 over-expression in TG mice results in adenomyotic changes reversed by HSD17B1 inhibitor treatment and HSD17B1 is, thus, a potential novel drug target for adenomyosis.

The Potential Relationship Between Environmental Endocrine Disruptor Exposure and the Development of Endometriosis and Adenomyosis

Women with endometriosis, the growth of endometrial glands and stroma outside the uterus, commonly also exhibit adenomyosis, the growth of endometrial tissues within the uterine muscle. Each disease is associated with functional alterations in the eutopic endometrium frequently leading to pain, reduced fertility, and an increased risk of adverse pregnancy outcomes. Although the precise etiology of either disease is poorly understood, evidence suggests that the presence of endometriosis may be a contributing factor to the subsequent development of adenomyosis as a consequence of an altered, systemic inflammatory response. Herein, we will discuss the potential role of exposure to environmental toxicants with endocrine disrupting capabilities in the pathogenesis of both endometriosis and adenomyosis. Numerous epidemiology and experimental studies support a role for environmental endocrine disrupting chemicals (EDCs) in the development of endometriosis; however, only a few studies have examined the potential relationship between toxicant exposures and the risk of adenomyosis. Nevertheless, since women with endometriosis are also frequently found to have adenomyosis, discussion of EDC exposure and development of each of these diseases is relevant. We will discuss the potential mechanisms by which EDCs may act to promote the co-development of endometriosis and adenomyosis. Understanding the disease-promoting mechanisms of environmental toxicants related to endometriosis and adenomyosis is paramount to designing more effective treatment(s) and preventative strategies.

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.

Seven Hormonal Biomarkers for Diagnosing Endometriosis: Meta-Analysis and Adjusted Indirect Comparison of Diagnostic Test Accuracy

OBJECTIVE

To compare the diagnostic accuracy of different hormonal biomarkers and to find the most effective hormonal biomarker for the diagnosis of endometriosis.

DATA SOURCES

We conducted a systematic search using PubMed, EMBASE, Cochrane Library, and China Biomedical Literature to identify relevant studies from the first day of databases to August 2018.

METHODS OF STUDY SELECTION

Two independent reviewers screened for study eligibility and extracted data. Random controlled trials, cross-sectional studies, case-control studies, and cohort studies evaluating the diagnostic accuracy of hormonal markers for endometriosis were included.

TABULATION, INTEGRATION, AND RESULTS

We included 17 studies that involved 1279 participants and evaluated 7 hormonal biomarkers. The pooled sensitivity and specificity in endometriosis were .79 (.71, .86) and .89 (.82, .94) for aromatase, .30 (.18, .46) and .80 (.65, .90) for human chorionic gonadotropin/luteinizing hormone receptor, .75 (.66, .83) and .47 (.34, .60) for estrogen receptor (ER)-α, .65 (.56, .74) and .68 (.55, .80) for ER-β, .45 (.38-.52) and .92 (.85-.97) for serum prolactin, .69 (.51, .83) and .30 (.16, .49) for estrogen sulfotransferase, and .73 (.60-.84) and .48 (.33-.63) for 17β-hydroxysteroid dehydrogenase type 2 (17βHSD2). Compared with human chorionic gonadotropin/luteinizing hormone receptor, ER-α, ER-β, estrogen sulfotransferase, and 17βHSD2, aromatase had a higher sensitivity, specificity, positive likelihood ratio, and diagnostic odds ratio. The specificities of aromatase and serum prolactin were comparable, but the sensitivity, positive likelihood ratio, and positive likelihood ratio of serum prolactin were much lower than that of aromatase.

CONCLUSION

Aromatase may be an excellent diagnostic test for endometriosis. However, because of the moderate quality of the included studies and the limited sample size, this result requires more research to validate. (PROSPERO registration number: PROSPERO 2018 CRD42018105126.).

[Role of estrogen, estrogen receptors, and aromatase in the pathogenesis of uterine adenomyosis]

OBJECTIVE

To study the role of estrogen (E2), estrogen receptor (ER) and aromatase (P450arom) in the pathogenesis of uterine adenomyosis.

METHODS

Paraffin-embedded specimens of the uterine tissue from patients with uterine adenomyosis and patients with cervical lesions (CIN; control) were examined for expressions of E2, ER and P450arom by immunohistochemistry and ELISA. The cells isolated from the lesions of patients with adenomyosis were cultured in vitro, and the changes in cell growth in response to treatments with E2, ER inhibitor, ER inhibitor + E2, estrogen deprivation, and estrogen deprivation+ ICI182780 were assessed using CCK-8 method.

RESULTS

The expression levels of E2, ER, and P450arom were significantly higher in adenomyosis ectopic lesions and eutopic endometrium than in the myometrium and endometrium in the control group (P<0.05); no significant difference in E2 and P450arom expressions was found between adenomyosis ectopic lesions and eutopic endometrium (P>0.05), while the expression levels of ER in ectopic lesions was significantly higher than that in eutopic endometrium. The cell inhibition rates were similar between ER inhibitor group and ER inhibitor + Estrogen activation group (P>0.05), and was significantly higher in estrogen deprivation+ ER inhibitor group than in estrogen deprivation group (P<0.05).

CONCLUSION

The high expression levels of E2, ER, and P450arom in adenomyosis ectopic lesions and eutopic endometrium promote uterine adenomyosis cell proliferation, in which process E2 combines with ER to execute its biological effect; ER also promotes the occurrence and development of uterine adenomyosis through other pathways.

Endometrial biomarkers for the non-invasive diagnosis of endometriosis

BACKGROUND

About 10% of reproductive-aged women suffer from endometriosis, which is a costly, chronic disease that causes pelvic pain and subfertility. Laparoscopy is the gold standard diagnostic test for endometriosis, but it is expensive and carries surgical risks. Currently, there are no non-invasive tests available in clinical practice that accurately diagnose endometriosis. This is the first diagnostic test accuracy review of endometrial biomarkers for endometriosis that utilises Cochrane methodologies, providing an update on the rapidly expanding literature in this field.

OBJECTIVES

To determine the diagnostic accuracy of the endometrial biomarkers for pelvic endometriosis, using a surgical diagnosis as the reference standard. We evaluated the tests as replacement tests for diagnostic surgery and as triage tests to inform decisions to undertake surgery for endometriosis.

SEARCH METHODS

We did not restrict the searches to particular study designs, language or publication dates. To identify trials, we searched the following databases: CENTRAL (2015, July), MEDLINE (inception to May 2015), EMBASE (inception to May 2015), CINAHL (inception to April 2015), PsycINFO (inception to April 2015), Web of Science (inception to April 2015), LILACS (inception to April 2015), OAIster (inception to April 2015), TRIP (inception to April 2015) and ClinicalTrials.gov (inception to April 2015). We searched DARE and PubMed databases up to April 2015 to identify reviews and guidelines as sources of references to potentially relevant studies. We also performed searches for papers recently published and not yet indexed in the major databases. The search strategies incorporated words in the title, abstract, text words across the record and the medical subject headings (MeSH).

SELECTION CRITERIA

We considered published peer-reviewed, randomised controlled or cross-sectional studies of any size that included prospectively collected samples from any population of reproductive-aged women suspected of having one or more of the following target conditions: ovarian, peritoneal or deep infiltrating endometriosis (DIE).

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data from each study and performed a quality assessment. For each endometrial diagnostic test, we classified the data as positive or negative for the surgical detection of endometriosis and calculated the estimates of sensitivity and specificity. We considered two or more tests evaluated in the same cohort as separate data sets. We used the bivariate model to obtain pooled estimates of sensitivity and specificity whenever sufficient data were available. The predetermined criteria for a clinically useful test to replace diagnostic surgery was one with a sensitivity of 94% and a specificity of 79%. The criteria for triage tests were set at sensitivity at or above 95% and specificity at or above 50%, which in case of negative results rules out the diagnosis (SnOUT test) or sensitivity at or above 50% with specificity at or above 95%, which in case of positive result rules in the diagnosis (SpIN test).

MAIN RESULTS

We included 54 studies involving 2729 participants, most of which were of poor methodological quality. The studies evaluated endometrial biomarkers either in specific phases of the menstrual cycle or outside of it, and the studies tested the biomarkers either in menstrual fluid, in whole endometrial tissue or in separate endometrial components. Twenty-seven studies evaluated the diagnostic performance of 22 endometrial biomarkers for endometriosis. These were angiogenesis and growth factors (PROK-1), cell-adhesion molecules (integrins α3β1, α4β1, β1 and α6), DNA-repair molecules (hTERT), endometrial and mitochondrial proteome, hormonal markers (CYP19, 17βHSD2, ER-α, ER-β), inflammatory markers (IL-1R2), myogenic markers (caldesmon, CALD-1), neural markers (PGP 9.5, VIP, CGRP, SP, NPY, NF) and tumour markers (CA-125). Most of these biomarkers were assessed in single studies, whilst only data for PGP 9.5 and CYP19 were available for meta-analysis. These two biomarkers demonstrated significant diversity for the diagnostic estimates between the studies; however, the data were too limited to reliably determine the sources of heterogeneity. The mean sensitivities and specificities of PGP 9.5 (7 studies, 361 women) were 0.96 (95% confidence interval (CI) 0.91 to 1.00) and 0.86 (95% CI 0.70 to 1.00), after excluding one outlier study, and for CYP19 (8 studies, 444 women), they were were 0.77 (95% CI 0.70 to 0.85) and 0.74 (95% CI 0.65 to 84), respectively. We could not statistically evaluate other biomarkers in a meaningful way. An additional 31 studies evaluated 77 biomarkers that showed no evidence of differences in expression levels between the groups of women with and without endometriosis.

AUTHORS' CONCLUSIONS

We could not statistically evaluate most of the biomarkers assessed in this review in a meaningful way. In view of the low quality of most of the included studies, the findings of this review should be interpreted with caution. Although PGP 9.5 met the criteria for a replacement test, it demonstrated considerable inter study heterogeneity in diagnostic estimates, the source of which could not be determined. Several endometrial biomarkers, such as endometrial proteome, 17βHSD2, IL-1R2, caldesmon and other neural markers (VIP, CGRP, SP, NPY and combination of VIP, PGP 9.5 and SP) showed promising evidence of diagnostic accuracy, but there was insufficient or poor quality evidence for any clinical recommendations. Laparoscopy remains the gold standard for the diagnosis of endometriosis, and using any non-invasive tests should only be undertaken in a research setting. We have also identified a number of biomarkers that demonstrated no diagnostic value for endometriosis. We recommend that researchers direct future studies towards biomarkers with high diagnostic potential in good quality diagnostic studies.

Down-regulation of the CYP19A1 gene in cumulus cells of infertile women with endometriosis

Aromatase plays a fundamental role in the establishment of oocyte quality, which might be compromised in infertile women with endometriosis. The expression of the CYP19A1 gene (that encodes aromatase) was compared in cumulus cells and oestradiol concentrations in the follicular fluid of infertile women with and without endometriosis submitted to ovarian stimulation for intracytoplasmic sperm injection. Cumulus cells were isolated and the expression of the CYP19A1 was quantitated through real-time polymerase chain reaction. Oestradiol concentrations in follicular fluid were measured by chemiluminescence immunoassay. A lower expression of the CYP19A1 in the cumulus cells of infertile women with endometriosis was observed compared with controls (0.17 ± 0.13 and 0.56 ± 0.12, respectively), and no significant difference in the follicular fluid oestradiol concentrations was observed between groups. Our results show reduced expression of the CYP19A1 in cumulus cells of infertile women with endometriosis, which may play a role in the pathogenesis of endometriosis-related infertility.

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.

The effect of oral contraceptives on aromatase and Cox-2 expression in the endometrium of patients with idiopathic menorrhagia or adenomyosis

Background

The presence of aromatase and cyclooxygenase-2 (Cox-2) expression was investigated in the endometrium of patients with idiopathic menorrhagia or adenomyosis. The effect of oral contraceptives administered in extended regimens on the endometrial expression of these enzymes was also investigated.

Methods and results

Aromatase expression was detected by immunohistochemistry in the endometrial glands and stroma of patients with idiopathic menorrhagia or adenomyosis. There was no difference in the percentage of aromatase expression in the endometria between the two groups. The mean intensity of Cox-2 expression in the glandular epithelium also did not differ significantly between the groups. Among the patients using oral contraceptives in extended regimens, the relative decrease in both aromatase and Cox-2 expression was significantly greater in amenorrheic patients compared with those who were experiencing breakthrough bleeding.

Conclusion

The presence of aromatase expression in the endometrium is associated with the occurrence of menorrhagia, irrespective of the presence of adenomyosis. Continuous expression of these enzymes in the endometrium of users of oral contraceptives in extended regimens is positively associated with the presence of breakthrough bleeding. This suggests a role for both aromatase and Cox-2 in the etiology of abnormal uterine bleeding.

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.

Advantages of the association of resveratrol with oral contraceptives for management of endometriosis-related pain

BACKGROUND

The effect of resveratrol on the management of endometriosis-related pain was investigated in 12 patients who failed to obtain pain relief during use of an oral contraceptive containing drospirenone + ethinylestradiol.

METHODS AND RESULTS

The addition of 30 mg of resveratrol to the contraceptive regimen resulted in a significant reduction in pain scores, with 82% of patients reporting complete resolution of dysmenorrhea and pelvic pain after 2 months of use. In a separate experiment, aromatase and cyclo-oxygenase-2 expression were investigated in the endometrial tissue of 42 patients submitted to laparoscopy and hysteroscopy for the management of endometriosis. Sixteen of these patients were using oral contraceptives alone prior to hospital admission, while the remaining 26 were using them in combination with resveratrol. Inhibition of both aromatase and cyclo-oxygenase-2 expression was significantly greater in the eutopic endometrium of patients using combined drospirenone + resveratrol therapy compared with the endometrium of patients using oral contraceptives alone.

CONCLUSION

These results suggest that resveratrol potentiates the effect of oral contraceptives in the management of endometriosis-associated dysmenorrhea by further decreasing aromatase and cyclo-oxygenase-2 expression in the endometrium.

The Endometrium in Adenomyosis

Eutopic and ectopic endometria of women with adenomyosis show a series of metabolic and molecular abnormalities that increase angiogenesis and proliferation, decrease apoptosis, allow local production of estrogens, create progesterone resistance, and impair cytokine expression. These changes enhance the ability of the endometrium to infiltrate the junctional zone myometrium and the growth of ectopic tissue. In addition, in these subjects several immunological abnormalities have been observed, together with an increased production of ‘free radicals’ leading to excessive growth of endometrial stromal cells that may facilitate the establishment of adenomyosis. A limiting factor is that these studies have been performed on hysterectomy specimens representing final stages of the disease. This increased knowledge has created new therapeutic options, including the block of local aromatase production through the use of selective estrogen receptor modulators, estrogen-progestin combinations and gonadotropin-releasing hormone super agonists. Also promising are investigations into the mechanism of dysmenorrhea and abnormal uterine bleeding.

Correlation between aromatase expression in the eutopic endometrium of symptomatic patients and the presence of endometriosis

Objective

To investigate whether aromatase expression in the eutopic endometrium correlates with the presence and severity of endometriosis in patients with infertility and/or dysmenorrhea undergoing laparoscopy and hysteroscopy.

Patients

The study involved 106 patients of reproductive age with symptoms of dysmenorrhea and infertility. Sixteen endometriosis-free asymptomatic patients were used as a control group.

Methods

Concomitant laparoscopy and hysteroscopy was carried out in all cases. An endometrial biopsy was taken to determine aromatase p450 expression by immunohistochemistry. Endometriosis was staged according to the American Society of Reproductive Medicine classification.

Results

Endometriosis was diagnosed by laparoscopy in 92/106 symptomatic patients. In this group, aromatase expression was detected in the eutopic endometrium of 66/92 patients with endometriosis (72%) and in 13/14 (95%) patients in the symptomatic, endometriosis-free group (P = 0.09). Aromatase expression was not detected in any patients from the control group. In the endometriosis group, aromatase expression was detected in the eutopic endometrium of 28/45 patients (62%) with American Society of Reproductive Medicine classification stage 1 of the disease, in 11/14 patients (78%) with stage II, 14/20 patients (70%) with stage III, and in 12/13 patients (92%) with stage IV; however, the difference was only statistically significant between stages I and IV (P = 0.04).

Conclusion

Aromatase expression in the endometrium was associated with the presence of dysmenorrhea and infertility irrespective of the presence of endometriosis. When endometriosis was present, however, there was a tendency for aromatase expression to be positively correlated with dysmenorrhea severity.

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.