From pathogenesis to clinical practice: Emerging medical treatments for endometriosis

Horizons in Endometriosis: Proceedings of the Montreux Reproductive Summit, 14-15 July 2023

Endometriosis is a complex and chronic gynaecological disorder that affects millions of women worldwide, leading to significant morbidity and impacting reproductive health. This condition affects up to 10% of women of reproductive age and is characterised by the presence of endometrial-like tissue outside the uterus, potentially leading to symptoms such as chronic pelvic pain, dysmenorrhoea, dyspareunia, and infertility. The Montreux summit brought a number of experts in this field together to provide a platform for discussion and exchange of ideas. These proceedings summarise the six main topics that were discussed at this summit to shed light on future directions of endometriosis classification, diagnosis, and therapeutical management. The first question addressed the possibility of preventing endometriosis in the future by identifying risk factors, genetic predispositions, and further understanding of the pathophysiology of the condition to develop targeted interventions. The clinical presentation of endometriosis is varied, and the correlation between symptoms severity and disease extent is unclear. While there is currently no universally accepted optimal classification system for endometriosis, several attempts striving towards its optimisation - each with its own advantages and limitations - were discussed. The ideal classification should be able to reconcile disease status based on the various diagnostic tools, and prognosis to guide proper patient tailored management. Regarding diagnosis, we focused on future tools and critically discussed emerging approaches aimed at reducing diagnostic delay. Preserving fertility in endometriosis patients was another debatable aspect of management that was reviewed. Moreover, besides current treatment modalities, potential novel medical therapies that can target underlying mechanisms, provide effective symptom relief, and minimise side effects in endometriotic patients were considered, including hormonal therapies, immunomodulation, and regenerative medicine. Finally, the question of hormonal substitution therapy after radical treatment for endometriosis was debated, weighing the benefits of hormone replacement.

Diagnostic and therapeutic approaches for endometriosis: a patent landscape

OBJECTIVE

The aim of this review is to analyze the patent filings and to systematize the main technological trends in patent protection for the diagnosis and therapeutics for endometriosis. Patent literature has also been explored to identify active inventors and applicants in this field.

METHODOLOGY

Patent search was carried out in the freely accessible patent search databases namely, patentscope using various combinations of the keywords "Endometriosis OR Adenomyosis" AND "Diagnostic OR Therapeutics" were used along with wildcard search queries in the "Title", "Abstract" and "Descriptions" fields.

RESULTS

A patent search revealed 144 patents describing inventions for diagnostic and therapeutic purposes of endometriosis. These patents include 26 patent applications in the diagnostic utility and 116 patent applications under the therapeutic approaches. Out of these 116 patent applications, 43 describe traditional medicines for endometriosis. Two patent applications describe inventions that can fall into both categories.

CONCLUSION

Efforts are being made to improve current diagnostic instruments. Hormonal alteration methods is the most common field of invention, followed by surgical interventions for therapeutics. A general trend of increase in patent application filings has been observed with a slight decrease in recent years.

A review of phase II and III drugs for the treatment and management of endometriosis

INTRODUCTION

Endometriosis is an estrogen-dependent disease that gives rise to pelvic pain and infertility. Although estroprogestins and progestins currently stand as the first-line treatments for this condition, demonstrating efficacy in two-thirds of patients, a significant portion of individuals experience only partial relief or symptom recurrence following the cessation of these therapies. The coexistence of superficial, deep endometriosis, and ovarian endometriomas, as three distinct phenotypes with unique pathogenetic and molecular characteristics, may elucidate the current heterogeneous biological response to available therapy.

AREAS COVERED

The objective of this review is to furnish the reader with a comprehensive summary pertaining to phase II-III hormonal treatments for endometriosis.

EXPERT OPINION

Ongoing research endeavors are directed toward the development of novel hormonal options for this benign yet debilitating disease. Among them, oral GnRH antagonists emerge as a noteworthy option, furnishing rapid therapeutic onset without an initial flare-up; these drugs facilitate partial or complete estrogen suppression, and promote prompt ovarian function recovery upon discontinuation, effectively surmounting the limitations associated with previously employed GnRH agonists. Limited evidence supports the use of selective estrogen and progesterone receptor modulators. Consequently, further extensive clinical research is imperative to garner a more profound understanding of innovative targets for novel hormonal options.

Cannabis and Endometriosis: The Roles of the Gut Microbiota and the Endocannabinoid System

Endometriosis, a chronic condition affecting around 10-14% of women, is challenging to manage, due to its complex pathogenesis and limited treatment options. Research has suggested a potential role of the gut microbiota and the endocannabinoid system in the development and progression of endometriosis. This narrative review aims to explore the role of, and any potential interactions between, the endocannabinoid system (ECS) and the gut microbiota in endometriosis. This review found that both the ECS and microbiota influence endometriosis, with the former regulating inflammation and pain perception and the latter influencing immune responses and hormonal balance. There is evidence that a dysregulation of the endocannabinoid system and the gut microbiota influence endometriosis symptoms and progression via changes in CB1 receptor expression and increased circulating levels of endocannabinoids. Microbial imbalances in the gut, such as increases in Prevotella, have been directly correlated to increased bloating, a common endometriosis symptom, while increases in E. coli have supported the bacterial contamination hypothesis as a potential pathway for endometriosis pathogenesis. These microbial imbalances have been correlated with increases in inflammatory markers such as TNF-α and IL-6, both often raised in those with endometriosis. Protective effects of the ECS on the gut were observed by increases in endocannabinoids, including 2-AG, resulting in decreased inflammation and improved gut permeability. Given these findings, both the ECS and the gut microbiota may be targets for therapeutic interventions for endometriosis; however, clinical studies are required to determine effectiveness.

Bioinformatics Analysis Reveals Novel Differentially Expressed Genes Between Ectopic and Eutopic Endometrium in Women with Endometriosis

Background

Endometriosis is one of the chronic and prevalent diseases among women. There is limited knowledge about its pathophysiology at the cellular and molecular levels, causing a lack of a definite cure for this disease. In this study, differentially expressed genes (DEGs) between ectopic and paired eutopic endometrium in women with endometriosis were analyzed through bioinformatics analysis for better understanding of the molecular pathogenesis of endometriosis.

Methods

Gene expression data of ectopic and paired eutopic endometrium were taken from the Gene Expression Omnibus database. DEGs were screened by the Limma package in R with considering specific criteria. Then, the protein-protein interaction network was reconstructed between DEGs. The fast unfolding clustering algorithm was used to find sub-networks (modules). Finally, the three most relevant modules were selected and the functional and pathway enrichment analyses were performed for the selected modules.

Results

A total of 380 DEGs (245 up-regulated and 135 down-regulated) were identified in the ectopic endometrium and compared with paired eutopic endometrium. The DEGs were predominantly enriched in an ensemble of genes encoding the extracellular matrix and associated proteins, metabolic pathways, cell adhesions and the innate immune system. Importantly, DPT, ASPN, CHRDL1, CSTA, HGD, MPZ, PED1A, and CLEC10A were identified as novel DEGs between the human ectopic tissue of endometrium and its paired eutopic endometrium.

Conclusion

The results of this study can open up a new window to better understanding of the molecular pathogenesis of endometriosis and can be considered for designing new treatment modalities.

Exploring Patient Adherence to Post-Surgical Follow-Up in Pelvic Endometriosis

Endometriosis is a significant cause of disability that affects 5-10% of reproductive-aged women. Laparoscopy with histological confirmation is the gold standard in establishing the diagnosis as therapeutic management surgery is addressed to a certain category of patients. The objective of this study was to assess patient adherence to follow-up after surgery for endometriosis as the primary endpoint, pain symptoms, quality of life, mental health, and fertility as the secondary endpoints. We have analyzed patients' adherence to follow-up after surgery for endometriosis after 1, 3, 5, and 7 years. Out of the 2538 total number of surgeries, 453 patients replied just to the first questionnaire (group A), 528 to the first and second (group B), and only 356 carried out the entire follow-up schedule. General health was significantly lower for group A (46.6 vs. 56.4) but with no statistical difference in the post-surgical improvement in both groups. Pain level score improvement was lower for group A (10.5 vs. 18.8), which is statistically significant. In this light, laparoscopy still remains the gold standard in diagnosis only. Furthermore, no malignancy was discovered. The mental component was improved by laparoscopy based on SF-36 in group B. Studies on patient preference for surgery versus alternative treatment are needed.

Progesterone receptor ligands for the treatment of endometriosis

Estrogen dependence and progesterone resistance play a crucial role in the origin and development of endometriosis. Therefore, hormonal therapies are currently the most effective treatment. Progestins are considered the first-line approach, especially for a long-term management. Progestins are synthetic compounds that mimic the effects of progesterone by binding progesterone receptors. Continuous use of progestins leads to the suppression of ovarian steroidogenesis with anovulation and low serum levels of ovarian steroids, causing endometrial pseudodecidualization. Moreover, they act by interfering on several endometriosis pathogenetic pathways, decreasing inflammation, provoking apoptosis in endometriotic cells, stimulating atrophy or regression of endometrial lesions, inhibiting angiogenesis, and decreasing expression of metalloproteinases, thus diminishing the invasiveness of endometriotic implants. Progestins are effective for pain relief and improvement of the quality of life (QoL). The side effects are limited, and the compounds are available in different formulations and routes of administration and represent, in most cases, an inexpensive treatment option. Dienogest, Medroxyprogesterone acetate and Norethisterone acetate are the labeled progestins for endometriosis, but other progestins, such as Dyhidrogesterone, Levonorgestrel and Desogestrel, have been shown to be effective in the treatment of endometriosis-associated pain. The present review aims to describe the available and emerging evidences on progestins used for the treatment of endometriosis.

Network pharmacology and experimental validation to explore the potential mechanism of Sanjie Zhentong Capsule in endometriosis treatment

PURPOSE

Sanjie Zhentong Capsule (SZC) is gradually becoming widely used in the treatment of endometriosis (EMs) and has demonstrated an excellent curative effect in the clinic. However, the active components and mechanisms of Sanjie Zhentong Capsule (SZC) in the treatment of endometriosis (EMs) remain unclear, and further research is needed to explore the effects of Sanjie Zhentong Capsule (SZC).

MATERIALS AND METHODS

First, a drug target database of Sanjie Zhentong capsule (SZC) was established by consulting the TCMSP database and related literature. An endometriosis (EMs) disease target database was then established by consulting the GeneCards, OMIM and Drug Bank databases. The overlapping genes of SZC and EMs were determined, and protein-protein interactions (PPIs), gene ontology (GO) and Kyoto Gene and Genome Encyclopedia (KEGG) analyses were performed to predict the potential therapeutic mechanisms. Molecular docking was used to observe whether the key active ingredients and targets predicted by network pharmacology had good binding energy. Finally, in vitro experiments such as CCK-8, flow cytometry and RT-PCR assays were carried out to preliminarily verify the potential mechanisms.

RESULTS

Through the construction of a pharmacological network, we identified a total of 28 active components in SZC and 52 potential therapeutic targets. According to GO and KEGG enrichment analyses, the effects of SZC treatment may be related to oxidative stress, steroid metabolism, apoptosis and proliferation. We also experimentally confirmed that SZC can regulate the expression of steroid hormone biosynthesis-related genes, inhibit ectopic endometrial stromal cell (EESC) proliferation and oxidative stress, and promote apoptosis.

CONCLUSION

This study explored the potential mechanism of SZC in the treatment of EMs through network pharmacology and experiments, providing a basis for further future research on SZC in the treatment of EMs.

The latest advances in the pharmacological management of endometriosis

INTRODUCTION

Endometriosis is a benign disease, characterized by a wide range of symptoms and different degrees of severity, which is why therapy should be individually adapted to the patient's needs. Over the years, a lot of research has gone into finding new therapeutic approaches for this enigmatic disease.

AREAS COVERED

This review presents the latest advances in pharmacological management of endometriosis and is solely focused on studies published from 2010 to 2021.

EXPERT OPINION

Clinicians and researchers are constantly searching for new therapeutic strategies for endometriosis patients. As there are well-established treatments, however, any new medication should fulfill at least one of the three criteria: increased efficacy, comparable efficacy but a better safety profile, or treatments that have a lack of accompanying contraceptive effects that are seen in most endometriosis treatments. While some new substances show promising results, further studies are needed to demonstrate the fulfillment of one of the above-mentioned criteria.

Hormonal drugs for the treatment of endometriosis

In the past, the primary approach for the treatment of endometriosis was represented by surgery; however, after the introduction of non-invasive diagnosis of endometriosis with the development of imaging technologies, medical treatment became the preferred approach, particularly in young patients. Hormonal drugs, by blocking menstruation, are the most effective for the treatment of endometriosis-related pain, independently of phenotype (ovarian, deep, or superficial endometriosis). Gonadotropin-releasing hormone analogs and oral antagonists act on hypothalamus-pituitary-ovary axis inducing iatrogenic menopause, thus reducing dysmenorrhea and all pain symptoms. The side effects, such as hot flushes and bone loss, may be reduced by an add-back therapy. However, the cost in terms of women's health remains high in view of a long-term treatment. Progestins are considered the first-line treatment, highly effective, and with reduced side effects. In addition to the well-known and largely used Norethisterone acetate and Medroxyprogesterone acetate, recently Dienogest has become one of the most used drugs in all endometriosis phenotypes for long-term treatment. Besides, Intrauterine levornogestrel or subcutaneous etonogestrel are valid alternative for long-term treatment.

Risk factors for coexisting deep endometriosis for patients with recurrent ovarian endometrioma

Aim

The aim of this study was to assess the risk factors for coexisting deep endometriosis (DE) in patients with recurrent ovarian endometrioma (OE).

Methods

We retrospectively reviewed 151 recurrent OE patients who had been diagnosed of OE but not DE at the time of their first surgery and then received a second surgery for recurrent endometriosis with or without DE. Their clinical characteristics at the time of the first and second surgeries were collected. Univariate and multivariate logistic regression analyses were conducted to identify potential risk factors for coexisting DE in patients with recurrent OE.

Results

Among the 151 recurrent OE patients, 46 were diagnosed of DE during the recurrent surgery and included in the DE group, while the remaining 105 patients were included in the non-DE group. In univariate analysis, there were significant differences in terms of uterine retroversion during the primary surgery and the follow-up time after the primary surgery between the DE and non-DE groups. The multivariate analysis also showed that both uterine retroversion and the follow-up time (≥5 years) were associated with the coexistence of DE during the recurrent surgery. The odds ratio (OR) for uterine retroversion was 3.72 [95% confidence interval (CI) 1.62–8.53], and the OR for follow-up time (≥5 years) was 5.03 (95% CI 2.29–11.02).

Conclusions

Our study suggested that for recurrent OE patients, uterine retroversion during the first surgery and a follow-up time of at least 5 years are risk factors for the coexistence of DE in recurrent surgery, early prevention and full preparation before the recurrent surgery should be emphasized in these conditions.

Advances in targeting estrogen synthesis and receptors in patients with endometriosis

INTRODUCTION

Endometriosis is an estrogen-dependent disease on the background of progesterone resistance. Increased estrogen production, low estrogen metabolization, and altered estrogen receptors (ERs) expression contribute to the hyperestrogenic milieu within endometriotic lesions. Since estrogens play a crucial role in the pathogenesis of the disease, inhibition of estrogen production is one of the main targets of available and emerging drugs.

AREAS COVERED

Firstly, we described the molecular alterations responsible for estrogen dependence. Secondly, we reviewed available and emerging treatments that interfere, through central (gonadotropin-releasing hormone analogs (GnRH-a), GnRH antagonists) or local mechanisms (aromatase inhibitors (AIs), inhibitors of steroid sulfatase (STS) and hydroxysteroid dehydrogenase type 1 (17β-HSD1)), with estrogen dependence. Finally, we focused on emerging treatments targeting ERs (selective estrogen receptor modulators (SERMs), estrogen receptors agonists, and antagonists).

EXPERT OPINION

Available treatments interfering with estrogen pathways exert a contraceptive effect, have hypoestrogenic side effects, and cannot prevent or definitively treat the disease. Preclinical and animal studies are focusing on emerging drugs targeting ERs in order to overcome limitations of available treatments. These treatments may represent a promising option, as they may produce a more specific inhibition of disease activity within endometriotic implants, avoiding prolonged hypoestrogenic status and limiting systemic side effects.

Novel pharmacological therapies for the treatment of endometriosis

INTRODUCTION

Endometriosis is a chronic, estrogen-dependent, inflammatory disease associated with pelvic pain, infertility, impaired sexual function, and psychological suffering. Therefore, tailored patient management appears of primary importance to address specific issues and identify the appropriate treatment for each woman. Over the years, abundant research has been carried out with the objective to find new therapeutic approaches for this multifaceted disease.

AREAS COVERED

This narrative review aims to present the latest advances in the pharmacological management of endometriosis. In particular, the potential role of GnRH antagonists, selective progesterone receptor modulators (SPRMs), and selective estrogen receptors modulators (SERMs) will be discussed. We performed a literature search in PubMed and Embase, and selected the best quality evidence, giving preference to the most recent and definitive original articles and reviews.

EXPERT OPINION

Medical therapy represents the cornerstone of endometriosis management, although few advances have been made in the last decade. Most studies have focused on the evaluation of the efficacy and safety of GnRH antagonists (plus add-back therapy in cases of prolonged treatment), which should be used as second-line treatment options in selected cases (i.e. non-responders to first-line treatments). Further studies are needed to identify the ideal treatment for women with endometriosis.

Lobaric acid prevents the adverse effects of tetramethrin on the estrous cycle of female albino Wistar rats

Tetramethrin (Tm) is a commonly used pesticide that has been reported to exert estrogen-antagonistic effects selectively on female rats. The present study was undertaken to assess the protective role of lobaric acid (La) on estrous cycle in Tm-treated female Wistar rats. Female rats were exposed to Tm (50 mg/kg b.w/day) only or in combination with La at low (50 mg/kg b.w/day) or high (100 mg/kg b.w/day) dose for 30 days. The results showed that Tm altered the estrous cycle of female rats by decreasing the levels of luteinizing hormone, follicular-stimulating hormone, progesterone, estrone, and estradiol while increasing testosterone level. The morphology of vaginal smears of Tm-treated female rats showed the presence of abnormal cells and/or structures at different phases of estrus cycle. Strikingly, in (Tm + La)-treated rats, all the observed adverse effects of Tm on the hormonal parameters, cell morphology, and the length of each phase of estrous cycle were significantly diminished in a dose-dependent manner. The docking results showed that La competes with Tm for Gonadotropin-Releasing Hormone (GnRH) receptor, thereby reducing the toxicity of Tm but did not cancel the response of GnRH receptor completely. In conclusion, our results designated that La could be used as a potential candidate in the management of insecticide-induced alterations of the reproductive cycle of rodents.

Hormonal treatments for endometriosis: The endocrine background

Endometriosis is a benign uterine disorder characterized by menstrual pain and infertility, deeply affecting women's health. It is a chronic disease and requires a long term management. Hormonal drugs are currently the most used for the medical treatment and are based on the endocrine pathogenetic aspects. Estrogen-dependency and progesterone-resistance are the key events which cause the ectopic implantation of endometrial cells, decreasing apoptosis and increasing oxidative stress, inflammation and neuroangiogenesis. Endometriotic cells express AMH, TGF-related growth factors (inhibin, activin, follistatin) CRH and stress related peptides. Endocrine and inflammatory changes explain pain and infertility, and the systemic comorbidities described in these patients, such as autoimmune (thyroiditis, arthritis, allergies), inflammatory (gastrointestinal/urinary diseases) and mental health disorders.The hormonal treatment of endometriosis aims to block of menstruation through an inhibition of hypothalamus-pituitary-ovary axis or by causing a pseudodecidualization with consequent amenorrhea, impairing the progression of endometriotic implants. GnRH agonists and antagonists are effective on endometriosis by acting on pituitary-ovarian function. Progestins are mostly used for long term treatments (dienogest, NETA, MPA) and act on multiple sites of action. Combined oral contraceptives are also used for reducing endometriosis symptoms by inhibiting ovarian function. Clinical trials are currently going on selective progesterone receptor modulators, selective estrogen receptor modulators and aromatase inhibitors. Nowadays, all these hormonal drugs are considered the first-line treatment for women with endometriosis to improve their symptoms, to postpone surgery or to prevent post-surgical disease recurrence. This review aims to provide a comprehensive state-of-the-art on the current and future hormonal treatments for endometriosis, exploring the endocrine background of the disease.

Long-term treatment of endometriosis-related pain among women seeking hormonal contraception

OBJECTIVE

To evaluate the different effects of a progestin-only contraceptive with desogestrel (DSG) vs combined oral contraceptives (COCs) for a first line long-term treatment of endometriosis-related pain among patients seeking hormonal contraception.

METHODS

An observational retrospective cohort study was conducted in collaboration with a local outpatient clinic for endometriosis among a group of nulliparous young women (n = 216) with endometriosis-related pain and seeking contraception. The cohort was subdivided into a group (n = 73) treated as first line by DSG and another group (n = 75) treated by a COC. During the study, clinical symptoms, side effects and possible changes in OC type use were recorded.

RESULTS

No significant difference was found between the two groups in terms of clinical characteristics and pain scores before treatment. After 6 months both treatments were effective in reducing endometriosis-related pain, and those treated with DSG showed lower levels of dysmenorrhea, dyspareunia and nonmenstrual pelvic pain than COCs group (p < .01). After 12 months, in DSG Group some patients (15%) switched from DSG to a COC for breakthrough bleeding, whereas in COC Group 48% of patients switched to another type of COC for reduced efficacy on pain and/or for side effects. After 3 years of OC treatment, in DSG Group 79% of patients maintained the same therapy, whereas in COC Group only 14% continued the same COC type, 37% switched to another COC and 47% to DSG.

CONCLUSIONS

A progestin-only contraceptive with DSG is a valid option for long term management of endometriosis-related pain in patients seeking hormonal contraception.

Risk Factors for Endometriosis Among Egyptian Infertile Women with Different Disease Stages

Background

Endometriosis is regarded as a benign condition, despite the potential for recurrence and metastasis,. It might lead to secondary ovarian cancer from endometrioma.

Objective

The aim of this current study was to determine the relationship between risk factors for endometriosis and disease stages.

Methods

This current cross-sectional study was performed at the endoscopic unit at Zagazig University Hospitals, Egypt. The participants included 85 women who were candidates for laparoscopy and diagnosed with endometriosis in the period from November 2019 to November 2020. The tools used for data collection were a structured interviewing form and the American Society of Reproductive Medicine scoring tool (ASRM) for determining stages of endometriosis.

Results

The high percentages of studied women were nulliparous (74.1%) and (51.8%) have secondary infertility. Endometriosis was staged as 20.0% minimal (ASRM stage I), 34.1% mild (ASRM stage II), 29.4% moderate (ASRM stage III), and 16.5% severe (ASRM stage IV). Congestive dysmenorrhea (78.8%), dyspareunia (77.6%), and secondary infertility (51.8%) were more reported symptoms in all stages of endometriosis.

Conclusion

This study concluded that women within reproductive age, nulliparity, lower body weight, urban residence, and past surgery of the pelvic were considered as risk factors in all disease stages.

Cannabidiol for the Management of Endometriosis and Chronic Pelvic Pain

OBJECTIVE

To review the available literature on the effect of cannabis-based products on the female reproductive system and establish if there is any evidence that they benefit or harm patients with endometriosis and therefore if there is sufficient evidence to recommend them.

DATA SOURCES

An electronic-based search was performed in PubMed, Embase and the Cochrane Database. Reference lists of articles retrieved were reviewed and a grey literature search was also performed.

METHODS OF STUDY SELECTION

The original database search yielded 264 articles from PubMed, Embase and the Cochrane Database, of which forty-one were included. One hundred and sixty-one studies relating to gynaecological malignancy, conditions unrelated to endometriosis or therapies unrelated to cannabis-based products were excluded. Twelve articles were included from a grey literature search and review of references.

RESULTS

The majority of available evidence is from laboratory studies aiming to simulate the effects of cannabis-based products on preclinical endometriosis models. Some show evidence of benefit with cannabis-based products. However, results are conflicting and the impact in humans cannot necessarily be extrapolated from this data. Few studies exist looking at the effect of cannabis or its derived products in women with endometriosis - the majority are in the form of surveys and are affected by bias. National guidance was also reviewed: at present this dictates that cannabis-based products can only be prescribed for conditions where there is clear published evidence of benefit and only when all other treatment options have been exhausted.

CONCLUSION

Current treatment options for endometriosis often affect fertility and/or have undesirable side effects that impede long-term management. Cannabis-based products have been suggested as a novel therapeutic option that may circumvent these issues. However, there is a paucity of well-designed, robust studies and randomised controlled trials looking at their use in the treatment of endometriosis. In addition, cannabis use has a potential for harm in the long term; with a possible association with 'cannabis use disorder', psychosis and mood disturbances. At present, national guidance cannot recommend cannabis-based products to patients in the UK due to lack of clear evidence of benefit. More comprehensive research into the impact of endocannabinoids in the context of endometriosis is required before their use can be recommended or prescribed.

The relation between endometrioma and ovarian cancer

INTRODUCTION

The relationship between endometrioma and ovarian cancer is a topic of discussion in the field of endometriosis and to date it is still debated whether ovarian endometriosis may represent a risk factor for ovarian cancers.

EVIDENCE ACQUISITION

A literature search was carried out using Cochrane Library, EMBASE, Medline and Google Scholar up to October 2020. Primary outcome of interest was ovarian cancer incidence in patients with endometriosis. Secondary outcome was ovarian cancer prognosis in patients with endometriosis compared to patient without endometriosis.

EVIDENCE SYNTHESIS

Patients with ovarian endometriosis has a slight increase risk of developing ovarian cancer (merely 1.8%), being the general population risk for ovarian cancer 1.31%. In patient at postmenopausal age, long-lasting endometriosis, early-age diagnosis, infertility and/or infertility treatment the risk of developing ovarian cancer is higher. Endometriosis-related ovarian cancers are generally clear cell and endometrioid and are diagnosed at early stage compared to non-endometriosis related ovarian cancer.

CONCLUSIONS

The lifetime risk for ovarian cancer is low in endometriosis patients in general and higher in subgroups of patients allowing a tailored management based on patient characteristics. Endometriosis is a chronic disease negatively affecting the quality of life, nonetheless, concerns on ovarian cancer should be avoided in order to reduce the burden of the disease on women's health.

In vivo effects of AZD4547, a novel fibroblast growth factor receptor inhibitor, in a mouse model of endometriosis

Endometriosis is a chronic disease, characterized by the growth of endometrial-like cells outside the uterine cavity. Due to its complex pathophysiology, a totally resolving cure is yet to be found. The aim of this study was to compare the therapeutic efficacy of AZD4547, a novel fibroblast growth factor receptor inhibitor (FGFRI), with a well-characterized progestin, etonogestrel (ENG) using a validated in vivo mouse model of endometriosis. Endometriosis was induced by transplanting uterine fragments from donor mice in proestrus into the peritoneal cavity of recipient mice, which then developed into cyst-like lesions. AZD4547 and ENG were administered systemically either from the day of endometriosis induction or 2-weeks post-surgery. After 20 days of treatment, the lesions were harvested; their size and weight were measured and analyzed histologically or by qRT-PCR. Stage of estrous cycle was monitored throughout. Compared to vehicle, AZD4547 (25 mg/kg) was most effective in counteracting lesion growth when treating from day of surgery and 2 weeks after; ENG (0.8 mg/kg) was similarly effective in reducing lesion growth but only when administered from day of surgery. Each downregulated FGFR gene expression (p < 0.05). AZD4547 at all doses and ENG (0.008 mg/kg) caused no disturbance to the estrous cycle. ENG at 0.08 and 0.8 mg/kg was associated with partial or complete estrous cycle disruption and hyperemia of the uteri. AZD4547 and ENG both attenuated endometriotic lesion size, but only AZD4547 did not disrupt the estrous cycle, suggesting that targeting of FGFR is worthy of further investigation as a novel treatment for endometriosis.

Is primary dysmenorrhea a precursor of future endometriosis development?

Primary dysmenorrhea (PD) is the most common gynecologic disorder during adolescence and it is characterized by crampy lower abdominal pain that occurs during menstruation. Secondary dysmenorrhea, in contrast, has the same clinical features but occurs in women with a disease that could account for their symptoms (endometriosis, adenomyosis, uterine fibroids, pelvic inflammatory disease). Endometriosis is the most common cause of secondary dysmenorrhea and it should be considered in patients with persistent and clinically significant dysmenorrhea despite treatment. It is often diagnosed after a long delay, increasing the likelihood of pain chronicity and fertility problems at a later age. Women who suffer from dysmenorrhea in adolescence have higher risk of endometriosis in future. The open question is if endometriosis was already present at the onset of dysmenorrhea but undiagnosed or if PD favors subsequent development of endometriosis-associated pain. Since PD is associated with higher risk for developing chronic pain state and shares some of the same pain pathways of endometriosis (prostaglandins overproduction, inflammation, peripheral sensitization, central sensitization and abnormal stress responses), a correlation between PD and endometriosis is suggested. To know whether it is a risk factor for the development of endometriosis-associated pain may provide an opportunity for early intervention and prevention. The present review aims to investigate the clinical and pathogenetic features of PD and endometriosis in order to identify a possible association between the two conditions.

Rosiglitazone affects the progression of surgically‑induced endometriosis in a rat model

Endometriosis is closely associated with inflammatory reactions and angiogenesis. Whether PPARγ is a target for the treatment of endometriosis remains unknown. The present study was designed to investigate the impact of a PPARγ agonist (rosiglitazone, RSG) on endometriosis in a rat model and to identify the underlying mechanism. The endometriosis model was established in rats. The pathological state of the endometrium was examined using hematoxylin‑eosin staining. The microstructures of interest were visualized using electron microscopy. Western blot analysis and reverse transcription‑quantitative polymerase chain reaction were used to detect PPARγ and MAT2A expression. VEGF and caspase‑3 expression were investigated using immunohistochemistry. Pathological analysis revealed transparent and red nodules in the model group, and that vasoganglions were present all over the nodules. Endometrial epithelial hyperplasia was observed in the model group, and the shape was columnar. Increased interstitial cell numbers, with compact structure and abundant blood supply, were detected in the model group. Compared with the model group, incomplete epithelial structures with sparse interstitial cells and loose structure were observed in the pathological images from RSG treatment groups. Numerous inflammatory cells and poor blood supply were observed in the endometrial tissues, and the gland was filled mostly with vacuolar cells. Electron microscopy revealed that the tissue structure was integrated. Many vacuoles were formed within the endometrial tissue and the classical morphological changes of apoptotic cells were observed in RSG‑treated groups. Caspase‑3 and PPARγ expression increased and expression of VEGF and MAT2A decreased in RSG‑treated groups. Taken together, these results revealed that RSG impacts the development and progression of endometriosis likely by inhibiting angiogenesis and inducing apoptosis.

Long-term hormonal treatment reduces repetitive surgery for endometriosis recurrence

RESEARCH QUESTION

How effective is medical hormonal treatment in preventing endometriosis recurrence and in improving women's clinical symptoms and quality of life?

DESIGN

This observational cross-sectional study evaluated the effects of hormonal medical treatment (progestins, gonadotrophin-releasing hormone analogues or continuous oral contraceptives) on endometriosis recurrence, current clinical symptoms and quality of life in three groups of patients: Group A (n = 34), no hormonal treatment either before or after the first endometriosis surgery; Group B (n = 76), on hormonal treatment after the first endometriosis surgery; and Group C (n = 75), on hormonal treatment both before and after the first endometriosis surgery.

RESULTS

Group C patients were characterized by a lower rate of endometriosis reoperation (P = 0.011) and a lower rate of dysmenorrhoea (P = 0.006). Women who experienced repetitive endometriosis surgery showed worse physical (P = 0.004) and mental (P = 0.012) status than those who received a single surgery, independent of the treatment.

CONCLUSION

Hormonal treatments represent a valid cornerstone of endometriosis management and may be useful as an alternative to surgery, but also before surgery, to plan better, and after surgery in order to reduce the risk of recurrence. Medical counselling is very helpful in choosing the correct and individualized endometriosis treatment. In fact, the gold standard for modern endometriosis management is the individualized approach and surgery should be considered, depending on the clinical situation and a patient's symptoms.

Progesterone receptor ligands for the treatment of endometriosis: the mechanisms behind therapeutic success and failure

BACKGROUND

Despite intense research, it remains intriguing why hormonal therapies in general and progestins in particular sometimes fail in endometriosis.

OBJECTIVE AND RATIONALE

We review here the action mechanisms of progesterone receptor ligands in endometriosis, identify critical differences between the effects of progestins on normal endometrium and endometriosis and envisage pathways to escape drug resistance and improve the therapeutic response of endometriotic lesions to such treatments.

SEARCH METHODS

We performed a systematic Pubmed search covering articles published since 1958 about the use of progestins, estro-progestins and selective progesterone receptor modulators, to treat endometriosis and its related symptoms. Two reviewers screened the titles and abstracts to select articles for full-text assessment.

OUTCOMES

Progesterone receptor signalling leads to down-regulation of estrogen receptors and restrains local estradiol production through interference with aromatase and 17 beta-hydroxysteroid dehydrogenase type 1. Progestins inhibit cell proliferation, inflammation, neovascularisation and neurogenesis in endometriosis. However, progesterone receptor expression is reduced and disrupted in endometriotic lesions, with predominance of the less active isoform (PRA) over the full-length, active isoform (PRB), due to epigenetic abnormalities affecting the PGR gene transcription. Oxidative stress is another mechanism involved in progesterone resistance in endometriosis. Among the molecular targets of progesterone in the normal endometrium that resist progestin action in endometriotic cells are the nuclear transcription factor FOXO1, matrix metalloproteinases, the transmembrane gap junction protein connexin 43 and paracrine regulators of estradiol metabolism. Compared to other phenotypes, deep endometriosis appears to be more resistant to size regression upon medical treatments. Individual genetic characteristics can affect the bioavailability and pharmacodynamics of hormonal drugs used to treat endometriosis and, hence, explain part of the variability in the therapeutic response.

WIDER IMPLICATIONS

Medical treatment of endometriosis needs urgent innovation, which should start by deeper understanding of the disease core features and diverse phenotypes and idiosyncrasies, while moving from pure hormonal treatments to drug combinations or novel molecules capable of restoring the various homeostatic mechanisms disrupted by endometriotic lesions.

A Guide to Targeting the Endocannabinoid System in Drug Design

The endocannabinoid system (ECS) is one of the most crucial systems in the human organism, exhibiting multi-purpose regulatory character. It is engaged in a vast array of physiological processes, including nociception, mood regulation, cognitive functions, neurogenesis and neuroprotection, appetite, lipid metabolism, as well as cell growth and proliferation. Thus, ECS proteins, including cannabinoid receptors and their endogenous ligands’ synthesizing and degrading enzymes, are promising therapeutic targets. Their modulation has been employed in or extensively studied as a treatment of multiple diseases. However, due to a complex nature of ECS and its crosstalk with other biological systems, the development of novel drugs turned out to be a challenging task. In this review, we summarize potential therapeutic applications for ECS-targeting drugs, especially focusing on promising synthetic compounds and preclinical studies. We put emphasis on modulation of specific proteins of ECS in different pathophysiological areas. In addition, we stress possible difficulties and risks and highlight proposed solutions. By presenting this review, we point out information pivotal in the spotlight of ECS-targeting drug design, as well as provide an overview of the current state of knowledge on ECS-related pharmacodynamics and show possible directions for needed research.

Dopamine agonists as genital endometriosis target therapy

OBJECTIVE

The present study was to find a pathogenic evidence for dopamine agonist application in patients with endometriosis associated pain syndrome.

PATIENTS AND TECHNIQUE

The study involved 227 patients of reproductive age with histologically confirmed genital endometriosis (GE) of I-III degree according to ASRM classification. The control group included 12 women with no laparoscope detected gynecologic pathology. The levels of prolactin (PRL), peripheral blood (PB), and peritoneal fluid (PF) were evaluated by chemiluminescence immune assay. The pain syndrome was measured by McGill visual analogue scale. Statistica10 program (StatSoft, Inc., Tulsa, OK) was applied for obtained data processing.

RESULTS

A correlation was established between GE rate and levels of PRL and PB (Rs = 0.28, p < .05) as well as a correlation of PRL in PB and PF (Rs = 0.29, p < .05). Patients receiving cabergoline combined with hormone therapy standard schemes manifested considerable pain syndrome relief.

CONCLUSIONS

PRL involvement in GE pathogenesis and more intense therapeutic impact on pain syndrome in case of combined administration of dopamine and standard hormone therapy prove cabergoline application in clinical practice.

Overexpression of TGF-β enhances the migration and invasive ability of ectopic endometrial cells via ERK/MAPK signaling pathway

Endometriosis is a common gynecological disease with manifestations of endometrial-like tissue outside the uterus. Transforming growth factor-β (TGF-β) is known to facilitate a series of biological events in many cells, including migration. However, the roles of TGF-β in endometriosis still remain largely unknown. The aim of the present study was to discover the role of TGF-β1 in endometriosis development and progression and its associated mechanisms. It was demonstrated that the expression of TGF-β1 was significantly elevated in endometriosis in comparison with that in normal tissue. Overexpression of TGF-β increased the proliferation and upregulated proliferating cell nuclear antigen and cyclin D1 in endometrial stromal cells (ESCs). Furthermore, TGF-β overexpression also triggered a series of biological events occurring in ESCs, including cell migration and invasion, and activated the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) signaling pathway. The inhibition of the ERK/MAPK pathway reversed the previous effects of TGF-β overexpression. Collectively, the present results indicate that overexpression of TGF-β enhances the migration and invasion of ectopic ESCs via the ERK/MAPK signaling pathway, providing theoretical evidence for the development of new treatment methods targeting the TGF-β-ERK/MAPK signaling pathway for prophylaxis of endometriosis.

Decreased Expression of Cannabinoid Receptors in the Eutopic and Ectopic Endometrium of Patients with Adenomyosis

Objective

Adenomyosis is a common gynecologic benign disease that may have a life-long negative impact on women. Previous studies have indicated that the endocannabinoid system may participate in the progress of endometriosis. Our research aims to analyze the expression patterns of the typical cannabinoid receptors (CB1 and CB2), the main constituents of the endocannabinoid system, in endometrial samples derived from patients diagnosed as adenomyosis or not.

Methods

Eutopic and corresponding ectopic endometrium from 45 premenopausal women diagnosed as adenomyosis and normal endometrium from 34 age-matched women lacking evidence of adenomyosis were examined by immunohistochemistry and quantitative real-time polymerase chain reaction (qRT-PCR) to determine the CB1 and CB2 expression levels.

Results

In either the proliferative or the secretory phase, CB1 and CB2 protein and mRNA levels were both significantly lower in the eutopic and ectopic endometrium of adenomyosis when compared with normal endometrium. For women with adenomyosis, CB1 and CB2 protein and mRNA levels were much lower in the ectopic endometrium than the eutopic in both phases of the cycle. Both CB1 and CB2 protein and mRNA levels were increased during the secretory phase in normal endometrium, while CB1 lost its cyclic variation in the eutopic and ectopic endometrium from patients diagnosed as adenomyosis.

Conclusion

The decreased expression of CB1 and CB2 in the eutopic and ectopic endometrium from patients diagnosed as adenomyosis suggests that cannabinoid receptors may participate in the pathogenesis of adenomyosis.

HORMONAL THERAPY IN WOMEN OF REPRODUCTIVE AGE WITH ENDOMETRIOSIS: AN UPDATE

Medical therapy of endometriosis is under continuous reevaluation. Hereby we updated the drugs currently available or under investigation for the hormonal treatment of endometriosis.

Endometriosis and in vitro fertilisation

The aim of the present review was to discuss a matter of concern in the clinical field of obstetrics/gynecology, namely the potency of in vitro fertilization (IVF) in the management of endometriosis-associated infertility. Endometriosis is a medical condition affecting one tenth of women in their fertile years, and accounts for up to 50% of infertile women. Thus, such high prevalence has established the necessity for investigating the effectiveness of available techniques in eradicating the disease and constraining infertility as well as the accompanying pain symptoms of endometriosis. The underlying mechanisms connecting endometriosis with low fecundity have been extensively studied, both in terms of genetic alterations and epigenetic events that contribute to the manifestation of an infertility phenotype in women with the disease. Several studies have dealt with the impact of IVF in pregnancy rates (PRs) on patients with endometriosis, particularly regarding women who wish to conceive. Results retrieved from studies and meta-analyses depict a diverse pattern of IVF success, underlining the involvement of individual parameters in the configuration of the final outcome. The ultimate decision on undergoing IVF treatment should be based on objective criteria and clinicians' experience, customized according to patients' individual needs.