A comparison of progestogens or oral contraceptives and gonadotropin-releasing hormone agonists for the treatment of endometriosis: a systematic review

Insight into the Potential Mechanisms of Endocrine Disruption by Dietary Phytoestrogens in the Context of the Etiopathogenesis of Endometriosis

Phytoestrogens (PEs) are estrogen-like nonsteroidal compounds derived from plants (e.g., nuts, seeds, fruits, and vegetables) and fungi that are structurally similar to 17β-estradiol. PEs bind to all types of estrogen receptors, including ERα and ERβ receptors, nuclear receptors, and a membrane-bound estrogen receptor known as the G protein-coupled estrogen receptor (GPER). As endocrine-disrupting chemicals (EDCs) with pro- or antiestrogenic properties, PEs can potentially disrupt the hormonal regulation of homeostasis, resulting in developmental and reproductive abnormalities. However, a lack of PEs in the diet does not result in the development of deficiency symptoms. To properly assess the benefits and risks associated with the use of a PE-rich diet, it is necessary to distinguish between endocrine disruption (endocrine-mediated adverse effects) and nonspecific effects on the endocrine system. Endometriosis is an estrogen-dependent disease of unknown etiopathogenesis, in which tissue similar to the lining of the uterus (the endometrium) grows outside of the uterus with subsequent complications being manifested as a result of local inflammatory reactions. Endometriosis affects 10-15% of women of reproductive age and is associated with chronic pelvic pain, dysmenorrhea, dyspareunia, and infertility. In this review, the endocrine-disruptive actions of PEs are reviewed in the context of endometriosis to determine whether a PE-rich diet has a positive or negative effect on the risk and course of endometriosis.

Targeting YAP1 ameliorates progesterone resistance in endometriosis

STUDY QUESTION

Does YAP1 inhibition alleviate progesterone resistance in endometriosis?

SUMMARY ANSWER

YAP1 inhibition reduces progesterone resistance in vitro and in vivo.

WHAT IS KNOWN ALREADY

Progesterone resistance not only causes treatment failure for endometriosis but also inhibits eutopic endometrial cell proliferation, dysregulates decidualization, and reduces the success rates of pregnancy. Hippo/yes-associated protein 1 (YAP1) signaling pathway plays an important role in the pathogenesis of endometriosis.

STUDY DESIGN, SIZE, DURATION

Paraffin-embedded tissues containing paired endometriotic and endometrial specimens (n = 42) and serum samples isolated from normal controls (n = 15) or endometriotic patients with (n = 25) or without (n = 21) prior dienogest treatment were analyzed. A mouse model of endometriosis was also used to evaluate the effects of YAP1 inhibition on progesterone resistance.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Primary endometriotic and endometrial stromal cells treated with YAP1 inhibitor or miR-21 mimic/inhibitor were used for the in vitro studies including decidualization induction, chromatin immunoprecipitation (ChIP), and RNA immunoprecipitation. Tissue specimens and serum from human and mouse were used for immunohistochemistry staining, exosome isolation, and microRNA (miRNA) quantification, respectively.

MAIN RESULTS AND THE ROLE OF CHANCE

Herein, we report, by using ChIP-PCR and RNA-IP, that YAP1 inhibits progesterone receptor (PGR) expression through upregulation of miR-21-5p. Upregulation of miR-21-5p not only reduces PGR expression but also inhibits endometrial stromal cell decidualization. Indeed, levels of YAP1 and miR-21-5p are inversely correlated with the level of PGR in human endometrial samples. In contrast, knockdown of YAP1 or treatment with verteporfin (VP), a YAP1 inhibitor, reduces miR-21-5p expression, thus leading to an increase in PGR expression in ectopic endometriotic stromal cells. In the mouse model of endometriosis, treatment with VP increases PGR expression and enhances decidualization. More importantly, VP synergistically increases the treatment effect of progestin in causing the regression of endometriotic lesions and improves the decidualization capability of the endometrium. Interestingly, treatment with dienogest, a synthetic progestin, reduces YAP1 and miR-21-5p expression in human cells and in the mouse model of endometriosis. Patients who received dienogest treatment for 6 months show a significant decrease in serum extracellular vesicle-associated miR-21-5p level.

LARGE SCALE DATA

A public dataset (GSE51981) containing a large cohort of endometriotic tissues is available from the Gene Expression Omnibus (GEO).

LIMITATIONS, REASONS FOR CAUTION

A large cohort of clinical samples is needed to verify the current diagnostic value of miR-21-5p in future studies.

WIDER IMPLICATIONS OF THE FINDINGS

The reciprocal regulation of YAP1 and PGR suggests that combined YAP1 inhibitor and progestin may be a better therapeutic approach for treating endometriosis.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the Ministry of Science and Technology, Taiwan (MOST-111-2636-B-006-012, MOST-111-2314-B-006-075-MY3, and MOST-106-2320-B-006-072-MY3). The authors have no conflict of interest to disclose.

Aberrant epigenetic regulation of estrogen and progesterone signaling at the level of endometrial/endometriotic tissue in the pathomechanism of endometriosis

Endometriosis is a term referring to a condition whereby the endometrial tissue is found outside the uterine cavity. This progressive and debilitating condition affects up to 15% of women of reproductive age. Due to the fact that endometriosis cells may express estrogen receptors (ERα, Erβ, GPER) and progesterone (P4) receptors (PR-A, PR-B), their growth, cyclic proliferation, and breakdown are similar to the processes occurring in the endometrium. The underlying etiology and pathogenesis of endometriosis are still not fully explained. The retrograde transport of viable menstrual endometrial cells with the retained ability to attach within the pelvic cavity, proliferate, differentiate and invade into the surrounding tissue explains the most widely accepted implantation theory. Endometrial stromal cells (EnSCs) with clonogenic potential constitute the most abundant population of cells within endometrium that resemble the properties of mesenchymal stem cells (MSCs). Accordingly, formation of the endometriotic foci in endometriosis may be due to a kind of EnSCs dysfunction. Increasing evidence indicates the underestimated role of epigenetic mechanisms in the pathogenesis of endometriosis. Hormone-mediated epigenetic modifications of the genome in EnSCs or even MSCs were attributed an important role in the etiopathogenesis of endometriosis. The roles of excess estrogen exposure and P4 resistance were also found to be crucial in the development of epigenetic homeostasis failure. Therefore, the aim of this review was to consolidate the current knowledge regarding the epigenetic background of EnSCs and MSCs and the changed properties due to estrogen/P4 imbalances in the context of the etiopathogenesis of endometriosis.

Maintenance Therapy for Preventing Endometrioma Recurrence after Endometriosis Resection Surgery-A Systematic Review and Network Meta-analysis

OBJECTIVE

To evaluate the efficacy of different hormone therapies in preventing postoperative endometrioma recurrence.

DATA SOURCES

The MEDLINE, COCHRANE and Embase electronic databases were searched from inception to 30 April 2021.

METHODS OF STUDY SELECTION

Randomized, controlled trials (RCTs) or cohort studies including reproductive age women with endometriosis undergoing ovarian cystectomy or excision of endometriotic lesions compared the effects of postoperative adjuvant therapy [gonadotropin-releasing hormone agonist (GnRHa)] and postoperative maintenance hormone interventions for more than one year [i.e., oral contraceptive pills (OCPs), dienogest (DNG), levonorgestrel-releasing intrauterine system (LNGIUS)] on endometrioma recurrence .

TABULATION, INTEGRATION AND RESULTS

Data collection and analysis of the data were independently performed by two reviewers. A total of 11 studies were included, of which 2 were RCTs, and 9 were cohort studies. There were 2394 patients with 6 interventions (cases: 1665, 69.6%) and expectant management (cases: 729, 30.4%). Relative treatment effects were estimated using network meta-analysis (NMA) and ranked in descending order. The clinical effectiveness of these drugs (versus expectant management) was as follows: GnRHa plus DNG [odds ratio (OR), 0.04; 95% confidence interval (CI), 0.01-0.27], surface under the cumulative ranking (SUCRA)= 94.0; DNG (OR, 0.11; 95% CI, 0.04-0.32), SUCRA= 69.7; GnRHa plus OCP (OR, 0.12; 95% CI, 0.02-0.64), SUCRA= 63.4; GnRHa plus LNGIUS (OR, 0.13; 95% CI, 0.03-0.66), SUCRA= 59.4; and OCP (OR, 0.21; 95% CI, 0.13-0.36), SUCRA= 43.6. The effectiveness of GnRHa (OR, 0.47; 95% CI, 0.12-1.89), SUCRA= 17.3 was not significantly different from that of controls.

CONCLUSION

In NMA, combined postoperative adjuvant therapy and longer maintenance hormone treatment are better than a single agent in preventing postoperative endometrioma recurrence. GnRHa plus DNG maintenance treatment might be the most effective intervention. Large-scale RCTs of these agents are still required.

REGISTRATION OF SYSTEMATIC REVIEWS

Date of PROSPERO registration: 17 April 2021.

PROSPERO REGISTRATION NUMBER

CRD42021247291.

Obesity and risk of female reproductive conditions: A Mendelian randomisation study

BACKGROUND

Obesity is observationally associated with altered risk of many female reproductive conditions. These include polycystic ovary syndrome (PCOS), abnormal uterine bleeding, endometriosis, infertility, and pregnancy-related disorders. However, the roles and mechanisms of obesity in the aetiology of reproductive disorders remain unclear. Thus, we aimed to estimate observational and genetically predicted causal associations between obesity, metabolic hormones, and female reproductive disorders.

METHODS AND FINDINGS

Logistic regression, generalised additive models, and Mendelian randomisation (MR) (2-sample, non-linear, and multivariable) were applied to obesity and reproductive disease data on up to 257,193 women of European ancestry in UK Biobank and publicly available genome-wide association studies (GWASs). Body mass index (BMI), waist-to-hip ratio (WHR), and WHR adjusted for BMI were observationally (odds ratios [ORs] = 1.02-1.87 per 1-SD increase in obesity trait) and genetically (ORs = 1.06-2.09) associated with uterine fibroids (UF), PCOS, heavy menstrual bleeding (HMB), and pre-eclampsia. Genetically predicted visceral adipose tissue (VAT) mass was associated with the development of HMB (OR [95% CI] per 1-kg increase in predicted VAT mass = 1.32 [1.06-1.64], P = 0.0130), PCOS (OR [95% CI] = 1.15 [1.08-1.23], P = 3.24 × 10-05), and pre-eclampsia (OR [95% CI] = 3.08 [1.98-4.79], P = 6.65 × 10-07). Increased waist circumference posed a higher genetic risk (ORs = 1.16-1.93) for the development of these disorders and UF than did increased hip circumference (ORs = 1.06-1.10). Leptin, fasting insulin, and insulin resistance each mediated between 20% and 50% of the total genetically predicted association of obesity with pre-eclampsia. Reproductive conditions clustered based on shared genetic components of their aetiological relationships with obesity. This study was limited in power by the low prevalence of female reproductive conditions among women in the UK Biobank, with little information on pre-diagnostic anthropometric traits, and by the susceptibility of MR estimates to genetic pleiotropy.

CONCLUSIONS

We found that common indices of overall and central obesity were associated with increased risks of reproductive disorders to heterogenous extents in a systematic, large-scale genetics-based analysis of the aetiological relationships between obesity and female reproductive conditions. Our results suggest the utility of exploring the mechanisms mediating the causal associations of overweight and obesity with gynaecological health to identify targets for disease prevention and treatment.

Bone Mineral Density Changes Associated With Pregnancy, Lactation, and Medical Treatments in Premenopausal Women and Effects Later in Life

Bone mineral density (BMD) changes during the life span, increasing rapidly during adolescence, plateauing in the third decade of life, and subsequently entering a phase of age-related decline. In women, menopause leads to accelerated bone loss and an increase in fracture risk. Between peak bone mass attainment and menopause, BMD is generally stable and the risk of fracture is typically low. This time period is marked by life events such as pregnancy and lactation, which transiently decrease BMD, yet their long-term effects on fracture risk are less certain. BMD may also be altered by exposure to medications that affect bone metabolism (e.g., contraceptives, glucocorticoids, antidiabetic medications, antiepileptic drugs). Although oral contraceptives are often believed to be neutral with regard to bone health, depot medroxyprogesterone acetate (DMPA) and gonadotropin-releasing hormone (GnRH) agonists have been associated with decreases in BMD. Development of newer medical therapies, principally GnRH antagonists (e.g., ASP1707, elagolix, linzagolix, relugolix), for treatment of endometriosis-associated pelvic pain and heavy menstrual bleeding due to uterine fibroids has renewed interest in the short- and long-term impacts of changes in BMD experienced by premenopausal women. It is important to understand how these drugs influence BMD and put the findings into context with regard to measurement variability and naturally occurring factors that influence bone health. This review summarizes what is known about the effects on bone health pregnancy, lactation, and use of DMPA, GnRH agonists, and GnRH antagonists in premenopausal women and potential consequences later in life. ClinicalTrials.gov identifier: NCT03213457.

Estrogen- and Progesterone (P4)-Mediated Epigenetic Modifications of Endometrial Stromal Cells (EnSCs) and/or Mesenchymal Stem/Stromal Cells (MSCs) in the Etiopathogenesis of Endometriosis

Endometriosis is a common chronic inflammatory condition in which endometrial tissue appears outside the uterine cavity. Because ectopic endometriosis cells express both estrogen and progesterone (P4) receptors, they grow and undergo cyclic proliferation and breakdown similar to the endometrium. This debilitating gynecological disease affects up to 15% of reproductive aged women. Despite many years of research, the etiopathogenesis of endometrial lesions remains unclear. Retrograde transport of the viable menstrual endometrial cells with retained ability for attachment within the pelvic cavity, proliferation, differentiation and subsequent invasion into the surrounding tissue constitutes the rationale for widely accepted implantation theory. Accordingly, the most abundant cells in the endometrium are endometrial stromal cells (EnSCs). These cells constitute a particular population with clonogenic activity that resembles properties of mesenchymal stem/stromal cells (MSCs). Thus, a significant role of stem cell-based dysfunction in formation of the initial endometrial lesions is suspected. There is increasing evidence that the role of epigenetic mechanisms and processes in endometriosis have been underestimated. The importance of excess estrogen exposure and P4 resistance in epigenetic homeostasis failure in the endometrial/endometriotic tissue are crucial. Epigenetic alterations regarding transcription factors of estrogen and P4 signaling pathways in MSCs are robust in endometriotic tissue. Thus, perspectives for the future may include MSCs and EnSCs as the targets of epigenetic therapies in the prevention and treatment of endometriosis. Here, we reviewed the current known changes in the epigenetic background of EnSCs and MSCs due to estrogen/P4 imbalances in the context of etiopathogenesis of endometriosis. Graphical Abstract.

Endometriosis is a chronic systemic disease: clinical challenges and novel innovations

Endometriosis is a common disease affecting 5-10% of women of reproductive age globally. However, despite its prevalence, diagnosis is typically delayed by years, misdiagnosis is common, and delivery of effective therapy is prolonged. Identification and prompt treatment of endometriosis are essential and facilitated by accurate clinical diagnosis. Endometriosis is classically defined as a chronic, gynaecological disease characterised by endometrial-like tissue present outside of the uterus and is thought to arise by retrograde menstruation. However, this description is outdated and no longer reflects the true scope and manifestations of the disease. The clinical presentation is varied, the presence of pelvic lesions is heterogeneous, and the manifestations of the disease outside of the female reproductive tract remain poorly understood. Endometriosis is now considered a systemic disease rather than a disease predominantly affecting the pelvis. Endometriosis affects metabolism in liver and adipose tissue, leads to systemic inflammation, and alters gene expression in the brain that causes pain sensitisation and mood disorders. The full effect of the disease is not fully recognised and goes far beyond the pelvis. Recognition of the full scope of the disease will facilitate clinical diagnosis and allow for more comprehensive treatment than currently available. Progestins and low-dose oral contraceptives are unsuccessful in a third of symptomatic women globally, probably as a result of progesterone resistance. Oral gonadotropin-releasing hormone (GnRH) antagonists constitute an effective and tolerable therapeutic alternative when first-line medications do not work. The development of GnRH antagonists has resulted in oral drugs that have fewer side-effects than other therapies and has allowed for rapid movement between treatments to optimise and personalise endometriosis care. In this Review, we discuss the latest understanding of endometriosis as a systemic disease with multiple manifestations outside the parameters of classic gynaecological disease.

Contraception across transgender

Sexual and reproductive issues are essential elements of well-being in cisgenders as well as for the transgender population. Gender-affirming hormonal treatments (GAHTs) aim to induce phenotypical changes congruent with the desired gender and subsequent reduction of gender dysphoria. While genital surgical procedures including hysterectomy and/or adenectomy cause permanent loss of ability to conceive, GAHT may induce a varying degree of reversible loss of fertility. For these reasons, transgender men and women need to be counseled concerning contraceptive options and potential effects of treatment on reproductive function before initiating GAHT. The literature reports that sexual activity with genital involvement is performed by less than half of transgender persons who have been sexually active with a partner in the past. Testosterone (T) is the most commonly used compound in transmen and usually leads to amenorrhea within 1-12 months from first administration, however cessation of menses does not mean anovulation. Some studies report cases of unintended pregnancies among transgender men under masculinizing therapy, therefore T treatment cannot be considered a contraceptive option. Currently available contraceptive options have pros and cons in transmen and scarce literature exists on their use. The effects of GAHT on fertility in transwomen are even less well known. Prolonged estrogen exposure induces sperm suppression and morphological changes of the spermatozoa, however the degree of resulting pregnancy protection is unclear. Further research to inform the contraceptive counseling in this population is mandatory.

Medical therapy options for endometriosis related pain, which is better? A systematic review and network meta-analysis of randomized controlled trials

Our objective was to assess and rank different pharmacological interventions for relieving endometriosis-related pain. We conducted an online bibliographic search in different databases from their inception until March 2019. We included randomized controlled trials (RCTs) that assessed different medical therapies in the management of endometriosis-related pain. We applied this network meta-analysis (NMA) based on the frequentist approach using statistical package "netmeta" (version 1.0-1) in R software. Our main outcomes were the change in severity of pelvic pain, dysmenorrhea score, non-menstrual pelvic pain score, and dyspareunia score. Overall, 36 RCTs were included in this study (patients no. = 7942). Dienogest (0.94), combined hormonal contraceptives (CHCs) (0.782), and elagolix (0.38) were the highest-ranked interventions for reducing the severity of pelvic pain at three months, while at six months, gonadotropin-releasing hormone (GnRH) analogues (0.75), levonorgestrel-releasing intrauterine system (LNG-IUS) (0.73), and dienogest (0.65) were linked to more reduction in pelvic pain. The ranking p-score showed that GnRH analogues was the highest-ranked treatment for reducing dysmenorrhea at 3 months (1.00), while CHCs were the highest-ranked treatment at 6 months (0.97), followed by GnRH analogues (0.89). GnRH analogues (0.63) and elagolix (0.54) at three months while desogestrel (0.94) and CHCs (0.91) at six months were the highest-ranked treatment to reduce non-menstrual pelvic pain. GnRH analogues and elagolix were the highest-ranked pharmacologic therapies for reducing dyspareunia. In conclusion, CHCs, GnRH analogues, progesterone, and elagolix were the best approaches in reducing the pain of endometriosis.

Clinical studies investigating the use of leuprorelin in Asian women with endometriosis: a review

We aimed to examine how leuprorelin has been studied for the treatment of women with endometriosis in Asia. We conducted a literature search of PubMed, the Cochrane Library and ClinicalTrials.gov. This review includes randomised trials of women with endometriosis treated with leuprorelin in Asia. Phase I-IV clinical trials published between January 1 2000 and December 31 2016 and written in English were included. Four studies were identified, showing that leuprorelin significantly improves pain and quality of life. The oestrone and oestradiol levels are decreased by leuprorelin but can be increased using an 'add-back' therapy with conjugated equine oestrogen and methoxyprogesterone. Menopause is more common in women treated with leuprorelin. The bone mineral density is reduced in women treated with leuprorelin. There are limited studies investigating the use of leuprorelin for the treatment of endometriosis in Asian populations. However, the research that has been conducted supports the use of leuprorelin in an Asian population.

Comparative, open-label prospective study on the quality of life and sexual function of women affected by endometriosis-associated pelvic pain on 2 mg dienogest/30 µg ethinyl estradiol continuous or 21/7 regimen oral contraceptive

PURPOSE

To evaluate the effects of a continuous regimen combined oral contraceptive (COC) containing 2 mg dienogest and 30 µg ethinyl estradiol (DNG/EE) compared to a 21/7 regimen on the quality of life (QoL) and sexual function in women affected by endometriosis-associated pelvic pain.

METHODS

Sixty-three women constituted the Study group treated with DNG/EE COC continuous regimen; 33 women were given DNG/EE COC in a 21/7 regimen. To define the endometriosis-associated pelvic pain, the Visual Analogic Scale was used. The Short Form-36, Female Sexual Function Index (FSFI) and the Female Sexual Distress Scale (FSDS) were used to assess QoL, sexual function and sexual distress, respectively. The study included two follow-ups.

RESULTS

At 3 and 6 months of treatment there was an improvement in pain of the Study group (p < 0.001). The Control group underwent pain improvement at the second follow-up (p < 0.05). At the first and the second follow-ups, the Study group reported QoL improvements in all categories (p < 0.001). The Control group reported QoL improvements in all categories at the second follow-up (p < 0.05). At the first and the second follow-ups of the Study group, the FSFI total score had risen (p < 0.001), and the FSDS score had dropped (p < 0.001). An improvement of the FSFI score and a reduction of the FSDS score of the Control group was observed at the second follow-up (p < 0.001), but not at the first follow-up (p = NS).

CONCLUSIONS

Women on DNG/EE COC continuous regimen reported a reduction of endometriosis-associated pelvic pain and there was an improvement of their sexual activity and their QoL that was better than the DNG/EE 21/7 conventional regimen.

Canadian Contraception Consensus (Part 3 of 4): Chapter 8 - Progestin-Only Contraception

OBJECTIVE

To provide guidelines for health care providers on the use of contraceptive methods to prevent pregnancy and on the promotion of healthy sexuality.

OUTCOMES

Overall efficacy of cited contraceptive methods, assessing reduction in pregnancy rate, safety, ease of use, and side effects; the effect of cited contraceptive methods on sexual health and general well-being; and the relative cost and availability of cited contraceptive methods in Canada.

EVIDENCE

Published literature was retrieved through searches of Medline and The Cochrane Database from January 1994 to January 2015 using appropriate controlled vocabulary (e.g., contraception, sexuality, sexual health) and key words (e.g., contraception, family planning, hormonal contraception, emergency contraception). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies published in English from January 1994 to January 2015. Searches were updated on a regular basis in incorporated in the guideline to June 2015. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALUES

The quality of the evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1). CHAPTER 8: PROGESTIN-ONLY CONTRACEPTION: Summary Statements Recommendations.

Treatment of Endometriosis with the GnRHa Deslorelin and Add-Back Estradiol and Supplementary Testosterone

Background. This randomized, multicenter, open-label clinical trial was intended to generate pilot data on the efficacy and safety of the gonadotropin-releasing hormone agonist (GnRHa) deslorelin (D) with low-dose estradiol ± testosterone (E₂  ± T) add-back for endometriosis-related pelvic pain. Methods. Women with pelvic pain and laparoscopically confirmed endometriosis were treated with a six-month course of daily intranasal D with concurrent administration of either transdermal E₂, intranasal E₂, or intranasal E₂  + T. Efficacy data included evaluation of dyspareunia, dysmenorrhea, pelvic pain, tenderness, and induration. Cognition and quality of life were also assessed. Safety parameters included assessment of endometrial hyperplasia, bone mineral density (BMD), and hot flashes. Results. Endometriosis symptoms and signs scores decreased in all treatment arms from a baseline average of 7.4 to 2.5 after 3 months of treatment and 3.4 after 6 months. BMD changes and incidence of hot flashes were minimal, and no endometrial hyperplasia was observed. Patient-reported outcomes showed significant improvement across multiple domains. Conclusions. Daily intranasal D with low dose E₂  ± T add-back resulted in significant reduction in severity of endometriosis symptoms and signs with few safety signals and minimal hypoestrogenic symptoms that would be expected with the use of a GnRHa alone.

Abundance and Localization of Progesterone Receptor Isoforms in Endometrium in Women With and Without Endometriosis and in Peritoneal and Ovarian Endometriotic Implants

BACKGROUND

Several studies suggest that resistance to progesterone may contribute to the pathophysiology of endometriosis. Progesterone mediates its biological activity via the 2 progesterone receptor (PR) isoforms (PR-A and PR-B). Effects of progesterone are determined by the PR-A:PR-B ratio such that a PR-B-dominant state promotes progesterone signaling, whereas a PR-A-dominant state decreases progesterone responsiveness. Our objective was to compare the abundance and cellular localization of the PR isoforms in endometrium and endometriotic lesions from women with and without peritoneal and ovarian endometriosis.

METHODS

This in vitro study was conducted in a tertiary care facility. Reproductive-age women with surgically diagnosed endometriosis (n = 18) and asymptomatic control individuals (n = 20) were prospectively recruited at the late proliferative and the early secretory phases. At laparoscopy, samples of eutopic endometrium, peritoneal and ovarian endometriosis, and disease-free peritoneum were obtained for subsequent immunohistochemical and immunoblot analysis of PR-B and total PR localization and PR-A and PR-B abundance, respectively.

RESULTS

The PR-A and PR-B were detected in eutopic endometrium and in peritoneal and ovarian endometriosis but not in disease-free peritoneum from patients with and without endometriosis. In peritoneal endometriosis, PR-A was the predominant isoform detected, whereas both receptors were detected in ovarian endometriosis and eutopic endometrium. In eutopic endometrium, levels of PR-A were significantly elevated in women with endometriosis compared with women without disease, regardless of menstrual phase. The PR-A levels were significantly elevated in ovarian endometriosis compared with peritoneal endometriosis.

CONCLUSIONS

Endometriotic lesions and eutopic endometrium from women with endometriosis are uniform in a PR-A-dominant state. The data suggest that menstrual efflux of a PR-A-dominant endometrial tissue into the peritoneal cavity may play a role in the pathophysiology of endometriosis.