Peripheral biomarkers of endometriosis: a systematic review

Holistic approach to care for patients with endometriosis

PURPOSE OF REVIEW

Endometriosis is a chronic, often debilitating, disease which is typically managed with surgery and hormonal medications. However, many patients feel they lack agency when managing endometriosis symptoms. The purpose of this review is to discuss the mental and physical management strategies, the long-term health consequences, and the role of a multidisciplinary team in the treatment of endometriosis.

RECENT FINDINGS

Evidence is becoming more robust regarding the role of complementary care and physical activity in the management of endometriosis. Health risks such as infertility are well known and newer evidence is evolving regarding perinatal and cardiovascular health risks. There are also trends towards multiple specialist involvement in the care of endometriosis and the benefit of interdisciplinary collaboration.

SUMMARY

Endometriosis is a frequently recurrent condition requiring not only meticulous medical and surgical care, but also coordinated longitudinal disease management and impact mitigation. Gynecologists should be aware of the short-term and long-term implications of the disease to empower patients on the management of their overall health.

Effect of catheter-directed ethanol sclerotherapy on ovarian reserve in patients with recurrent endometrioma: comparative analysis with primary endometriosis

OBJECTIVE

Catheter-directed ethanol sclerotherapy (CDS) is known to less affect the ovarian function, with comparable efficacy. This study aims to investigate the change in ovarian reserve after catheter-directed ethanol sclerotherapy in patients with recurrent endometrioma, as compared to primary endometrioma.

MATERIALS AND METHODS

Retrospective, observational study. Electronic medical records and images of patients with endometrioma who underwent CDS from August 2014 to April 2022 at a single institution were obtained. Patients aged > 18 years old and with anti-Müllerian hormone (AMH) level between 0.8 and 10.0 with regular menstruation were enrolled. Cyst diameter, laterality, AMH level, and CA-125 level before and after 1 month, 6 months, 1 year, 2 years, and 3 years of sclerotherapy were obtained.

RESULTS

A total of 180 patients were fit for analysis. There was no statistical difference in age and cyst size between the two groups. Mean values of AMH in each group were 3.35 in the primary group and 3.00 in the recurrent group prior to the procedure (p = 0.347). There was no significant difference in delta value of AMH after sclerotherapy in both groups at each follow-up period. Also, this result was consistent when stratified by laterality, preprocedural AMH level, and initial size of endometrioma. No case of recurrence was reported in both groups.

CONCLUSIONS

The effect of CDS on ovarian reserve is not inferior in recurrent endometrioma compared to primary endometrioma. Since sclerotherapy is known to less deteriorate the ovarian function than surgical removal of endometrioma, clinician could consider this as the first-line therapy in patients with recurrent endometrioma.

CLINICAL RELEVANCE STATEMENT

Catheter-directed ethanol sclerotherapy for patients with recurrent endometrioma has similar effect on ovarian reserve compared to patients with primary endometrioma.

KEY POINTS

• Secondary surgery for endometrioma has significant deleterious effect on ovarian function. • Catheter-directed sclerotherapy (CDS) for endometrioma had equally minimal adverse effect on ovarian reserve, represented as anti-Müllerian hormone (AMH), in both primary and recurrent groups. • Physicians should consider CDS for patients with recurrent endometrioma who desire to preserve ovarian function.

A Preliminary Investigation of the Roles of Endometrial Cells in Endometriosis Development via In Vitro and In Vivo Analyses

Endometriosis is a complex gynecological disease that affects more than 10% of women in their reproductive years. While surgery can provide temporary relief from women's pain, symptoms often return in as many as 75% of cases within two years. Previous literature has contributed to theories about the development of endometriosis; however, the exact pathogenesis and etiology remain elusive. We conducted a preliminary investigation into the influence of primary endometrial cells (ECs) on the development and progression of endometriosis. In vitro studies, they were involved in inducing Lipopolysaccharide (LPS) in rat-isolated primary endometrial cells, which resulted in increased nuclear factor-kappa B (NF-κB) and vascular endothelial growth factor (VEGF) mRNA gene expression (quantitative polymerase chain reaction analysis, qPCR) and protein expression (western blot analysis). Additionally, in vivo studies utilized autogenic and allogeneic transplantations (rat to rat) to investigate endometriosis-like lesion cyst size, body weight, protein levels (immunohistochemistry), and mRNA gene expression. These studies demonstrated that estrogen upregulates the gene and protein regulation of cytoskeletal (CK)-18, transforming growth factor-β (TGF-β), VEGF, and tumor necrosis factor (TNF)-α, particularly in the peritoneum. These findings may influence cell proliferation, angiogenesis, fibrosis, and inflammation markers. Consequently, this could exacerbate the occurrence and progression of endometriosis.

Endometriosis risk and hormonal contraceptive usage: A nationwide cohort study

OBJECTIVE

To investigate whether an early need of hormonal contraceptive (HC), or a failure to find a suitable method, are warning signs for endometriosis.

DESIGN

A retrospective cohort study.

SETTING

Sweden.

POPULATION

The cohort consisted of 720 805 women aged 12-27 years during the period 2005-2017. All women, regardless of whether they received a diagnosis of endometriosis or not (reference group), were included.

METHODS

We used data from Swedish national registers. Risks are expressed as crude and adjusted hazard ratios (HRs and aHRs, respectively) with 95% confidence intervals (95% CIs), adjusted for age, education level, civil status, parity, country of birth, and diagnoses of infertility, dysmenorrhea or depression.

MAIN OUTCOME MEASURES

A diagnosis of endometriosis between 12 and 27 years of age.

RESULTS

During this period, 3268 women were diagnosed with endometriosis (0.45%). Women who started HC at the ages of 12-14 years had a higher risk of receiving the diagnosis (aHR 2.53, 95% CI 2.21-2.90) than those who began at age 17 years or older. Having tried more types of HCs was associated with a twofold increased risk of endometriosis (more that three types of HC, aHR 2.31, 95% CI 1.71-3.12). Using HC for more than 1 year was associated with a decreased risk of endometriosis (>1 year, aHR 0.53, 95% CI 0.48-0.59). Women with endometriosis more commonly had dysmenorrhea, depression or infertility.

CONCLUSIONS

The use of HCs at an early age and a failure to find a suitable HC were identified as warning signs of later receiving an endometriosis diagnosis. A longer duration of HC usage reduced the risk of receiving the diagnosis.

Imaging of Endometriotic Lesions Using cRGD-MN Probe in a Mouse Model of Endometriosis

Approximately 10% of women suffer from endometriosis during their reproductive years. This disease is a chronic debilitating condition whose etiology for lesion implantation and survival heavily relies on adhesion and angiogenic factors. Currently, there are no clinically approved agents for its detection. In this study, we evaluated cRGD-peptide-conjugated nanoparticles (RGD-Cy5.5-MN) to detect lesions using magnetic resonance imaging (MRI) in a mouse model of endometriosis. We utilized a luciferase-expressing murine suture model of endometriosis. Imaging was performed before and after 24 h following the intravenous injection of RGD-Cy5.5-MN or control nanoparticles (Cy5.5-MN). Next, we performed biodistribution of RGD-Cy5.5-MN and correlative fluorescence microscopy of lesions stained for CD34. Tissue iron content was determined using inductively coupled plasma optical emission spectrometry (ICP-OES). Our results demonstrated that targeting endometriotic lesions with RGD-Cy5.5-MN resulted in a significantly higher delta T2* upon its accumulation compared to Cy5.5-MN. ICP-OES showed significantly higher iron content in the lesions of the animals in the experimental group compared to the lesions of the animals in the control group. Histology showed colocalization of Cy5.5 signal from RGD-Cy5.5-MN with CD34 in the lesions pointing to the targeted nature of the probe. This work offers initial proof-of-concept for targeting angiogenesis in endometriosis which can be useful for potential clinical diagnostic and therapeutic approaches for treating this disease.

Identification of miR-30c-5p microRNA in Serum as a Candidate Biomarker to Diagnose Endometriosis

The diagnosis of endometriosis by laparoscopy is delayed until advanced stages. In recent years, microRNAs have emerged as novel biomarkers for different diseases. These molecules are small non-coding RNA sequences involved in the regulation of gene expression and can be detected in peripheral blood. Our aim was to identify candidate serum microRNAs associated with endometriosis and their role as minimally invasive biomarkers. Serum samples were obtained from 159 women, of whom 77 were diagnosed with endometriosis by laparoscopy and 82 were healthy women. First, a preliminary study identified 29 differentially expressed microRNAs between the two study groups. Next, nine of the differentially expressed microRNAs in the preliminary analysis were evaluated in a new cohort of 67 women with endometriosis and 72 healthy women. Upon validation by quantitative real-time PCR technique, the circulating level of miR-30c-5p was significantly higher in the endometriosis group compared with the healthy women group. The area under the curve value of miR-30c-5p was 0.8437, demonstrating its diagnostic potential even when serum samples registered an acceptable limit of hemolysis. Dysregulation of this microRNA was associated with molecular pathways related to cancer and neuronal processes. We concluded that miR-30c-5p is a potential minimally invasive biomarker of endometriosis, with higher expression in the group of women with endometriosis diagnosed by laparoscopy.

Crimson clues: advancing endometriosis detection and management with novel blood biomarkers

Endometriosis is an inflammatory condition affecting approximately 10% of the female-born population. Despite its prevalence, the lack of noninvasive biomarkers has contributed to an established global diagnostic delay. The intricate pathophysiology of this enigmatic disease may leave signatures in the blood, which, when detected, can be used as noninvasive biomarkers. This review provides an update on how investigators are utilizing the established disease pathways and innovative methodologies, including genome-wide association studies, next-generation sequencing, and machine learning, to unravel the clues left in the blood to develop blood biomarkers. Many blood biomarkers show promise in the discovery phase, but because of a lack of standardized and robust methodologies, they rarely progress to the development stages. However, we are now seeing biomarkers being validated with high diagnostic accuracy and improvements in standardization protocols, providing promise for the future of endometriosis blood biomarkers.

The role of small extracellular vesicle-miRNAs in endometriosis

Endometriosis is defined by the presence of extrauterine endometrial-like tissue, which can cause pain and infertility in 10% of reproductive-age women. To date, the pathogenesis is poorly understood resulting in significant diagnostic delays and poor therapeutic outcomes in many women. Small extracellular vesicles (sEVs) (<200 nm) are cell-derived vesicles containing molecules that can influence gene expression and behaviour in target cells. One such cargo are microRNAs (miRNAs), which are short, non-coding RNAs mostly 19-25 nucleotides in length that regulate post-transcriptional gene expression. This mini-review focuses on the role of sEV-miRNAs, which are conceivably better biomarkers for endometriosis than free miRNAs, which reflect the true pathophysiological state in the body, as sEV-encapsulated miRNAs are protected from degradation compared to free miRNA and provide direct cell-to-cell communication via sEV surface proteins. sEV-miRNAs have been implicated in the immunomodulation of macrophages, the proliferation, migration and invasion of endometrial cells, and angiogenesis, all hallmarks of endometriosis. The diagnostic potential of sEV-miRNA was investigated in one study that reported the sensitivity and specificity of two sEV-miRNAs (hsa-miR-22-3p and hsa-miR-320a-3p) in distinguishing endometriosis from non-endometriosis cases. Only three studies have explored the therapeutic potential of sEV-miRNAs in vivo in mice-two looked into the role of sEV-hsa-miR-214-3p in decreasing fibrosis, and one investigated sEV-hsa-miR-30c-5p in suppressing the invasive and migratory potential of endometriotic lesions. While early results are encouraging, studies need to further address the potential influence of factors such as the menstrual cycle as well as the location and extent of endometriotic lesions on miRNA expression in sEVs. Given these findings, and extrapolating from other conditions such as cancer, diabetes, and pre-eclampsia, sEV-miRNAs could present an attractive and urgently needed future diagnostic and therapeutic target for millions of women suffering from endometriosis. However, research in this area is hampered by lack of adherence to the International Society for Extracellular Vesicles 2018 guideline in separating and characterising sEVs, as well as the World Endometriosis Research Foundation Endometriosis Phenome and Biobanking Harmonisation Project protocols.

Occupational characteristics and risk factors associated with endometriosis among Korean female workers

Endometriosis is a chronic and debilitating condition that affects daily working life. Characterization of the factors associated with endometriosis in the working population can facilitate the development of prevention and intervention strategies for those at risk of endometriosis. This population-based retrospective study was conducted using the 2007-2015 National Health Insurance Service-Female Employees database. Overall, 151,386 female workers aged 15-64 years were included in the study. Participants with endometriosis were identified using the diagnosis codes in the claims data. Multivariable Cox regression analyses were used to evaluate the effect of sociodemographic, lifestyle, health, and occupational factors on endometriosis risk. Of the 151,386 participants, 4,457 were diagnosed with endometriosis. The risk of endometriosis was significantly higher in 41-60 years group (HR = 1.47 (95% CI, 1.06-2.04)) and in those with body mass index (BMI) < 18.5 kg/m2 (HR = 1.16 (95% CI, 1.05-1.27)) than 15-20 years group and those with normal BMI, respectively. According to the international standard industrial classification, occupational groups with financial and insurance activities, public administration and defence, compulsory social security, and manufacturing were at a higher risk of endometriosis. Although there was no significant association between the risk of endometriosis and type of work, the cumulative prevalence of endometriosis from 2007 to 2015 continued to rise in office workers, manual workers, and both types of workers together. The risk of endometriosis was closely linked to the occupational characteristics of female workers. This study provides a foundation for developing occupational safety and health guidelines for female workers.

Detection of Endometriosis Lesions Using Gd-Based Collagen I Targeting Probe in Murine Models of Endometriosis

PURPOSE

Endometriosis is a chronic condition characterized by high fibrotic content and affecting about 10% of women during their reproductive years. Yet, no clinically approved agents are available for non-invasive endometriosis detection. The purpose of this study was to investigate the utility of a gadolinium-based collagen type I targeting probe (EP-3533) to non-invasively detect endometriotic lesions using magnetic resonance imaging (MRI). Previously, this probe has been used for detection and staging of fibrotic lesions in the liver, lung, heart, and cancer. In this study we evaluate the potential of EP-3533 for detecting endometriosis in two murine models and compare it with a non-binding isomer (EP-3612).

PROCEDURES

For imaging, we utilized two GFP-expressing murine models of endometriosis (suture model and injection model) injected intravenously with EP3533 or EP-33612. Mice were imaged before and after bolus injection of the probes. The dynamic signal enhancement of MR T1 FLASH images was analyzed, normalized, and quantified, and the relative location of lesions was validated through ex vivo fluorescence imaging. Subsequently, the harvested lesions were stained for collagen, and their gadolinium content was quantified by inductively coupled plasma optical emission spectrometry (ICP-OES).

RESULTS

We showed that EP-3533 probe increased the signal intensity in T1-weighted images of endometriotic lesions in both models of endometriosis. Such enhancement was not detected in the muscles of the same groups or in endometriotic lesions of mice injected with EP-3612 probe. Consequentially, control tissues had significantly lower gadolinium content, compared to the lesions in experimental groups. Probe accumulation was similar in endometriotic lesions of either model.

CONCLUSIONS

This study provides evidence for feasibility of targeting collagen type I in the endometriotic lesions using EP3533 probe. Our future work includes investigation of the utility of this probe for therapeutic delivery in endometriosis to inhibit signaling pathways that cause the disease.

Pathogenesis of Endometriosis: Focus on Adenogenesis-related Factors

Endometriosis can be defined as the presence of the endometrium outside the uterine cavity. It affects approximately 10% of women of reproductive age and causes infertility, chronic pain, and deterioration of the quality of life. Since the identification of the disease, various pathogenetic mechanisms have been proposed, such as retrograde menstruation, coelomic metaplasia, hormonal imbalance, stem cell involvement, and alterations in epigenetic regulation. However, the underlying pathogenesis of endometriosis remains inadequately understood. Elucidation of the precise mechanism of the development and progression of endometriosis is crucial for effective treatment. This review presents the major pathogenetic theories of endometriosis based on current research studies with a major focus on the potential role of uterine factors.

Biomarkers of endometriosis

Endometriosis is one of the most severe female reproductive disorders, affecting 6-10% of women between 18 and 35. It is a gynaecological condition where endometrial tissue develops and settles outside the uterus. The aetiology of endometriosis is primarily influenced by genetic, epigenetic, and non-genetic variables, making it highly challenging to create a therapeutic therapy explicitly targeting the ectopic tissue. The delay in the treatment is due to the limitations in the diagnostic approaches, which are restricted to invasive techniques such as laparoscopy or laparotomy. This accords to 70% of the women being diagnosed at later stages. By understanding the subject, several treatment medications have been produced to lessen the disease's symptoms. Nevertheless, endometriosis cannot be permanently cured. A viable or persuasive standard screening test for endometriosis must be utilized in a clinical context. A helpful assessment method for the early identification of endometriosis could be biomarkers. A major research priority is the identification of a biomarker that is sensitive and specific enough for detecting endometriosis. The present article has reviewed studies published on the expression of biomarkers of endometriosis. It outlines various biomarkers from different sample types, such as serum/plasma and urine, in addition to tissue. This would provide a non-invasive approach to diagnosing the disease at the initial stages without any harmful repercussions. Future high-throughput advances in science and technology are anticipated to result in the creation of a potent remedy for endometriosis. To achieve successful outcomes, it is necessary to research the discussed biomarkers that demonstrate substantial results extensively.

Effects of dysregulated glucose metabolism on the occurrence and ART outcome of endometriosis

BACKGROUND

Endometriosis is associated with systemic metabolic indicators, including body mass index (BMI), glucose metabolism and lipid metabolism, while the association between metabolic indexes and the occurrence and assisted reproductive technology (ART) outcome of endometriosis is unclear. We aimed to evaluate the characteristics of systemic metabolic indexes of endometriosis patients with infertility and their effects on pregnancy outcome after ART treatment.

METHODS

A retrospective cohort study involve 412 endometriosis patients and 1551 controls was conducted. Primary outcome was metabolic indexes, and secondary measures consisted of the influence of metabolic indexes on the number of retrieved oocytes and ART outcomes.

RESULTS

Endometriosis patients had higher insulin (INS) [6.90(5.10-9.50) vs 6.50(4.80-8.90) μU/mL, P = 0.005]. A prediction model for endometriosis combining the number of previous pregnancies, CA125, fasting blood glucose (Glu) and INS, had a sensitivity of 73.9%, specificity of 67.8% and area under curve (AUC) of 0.77. There were no significant differences in ART outcomes and complications during pregnancy. The serum levels of Glu before pregnancy were associated with GDM both in endometriosis group (aOR 12.95, 95% CI 1.69-99.42, P = 0.014) and in control group (aOR 4.15, 95% CI 1.50-11.53, P = 0.006).

CONCLUSIONS

We found serum Glu is related to the number of retrieved oocytes in control group, serum INS is related to the number of retrieved oocytes in endometriosis group, while serum Glu and INS before pregnancy are related to the occurrence of GDM in two groups. A prediction model based on metabolic indexes was established, representing a promising non-invasive method to predict endometriosis patients with known pregnancy history.

Diagnostic Clues for Women with Acute Surgical Abdomen Associated with Ruptured Endometrioma

(1) Background: An investigation of the preoperative diagnostic clues used to identify ruptured endometrioma by comparing the ruptured and unruptured states in patients who underwent laparoscopic operations due to endometrioma. (2) Methods: Patients with ruptured endometriomas (14 patients) and unruptured endometriomas (60 patients) were included, and clinical symptoms, laboratory findings, and radiological findings were analyzed. (3) Results: There were no significant differences in age, parity, last menstrual cycle days, or median size of endometrioma between two groups (group A: ruptured; group B: unruptured). The median serum level of CA 125 was 345.1 U/mL in group A and 49.8 U/mL in group B (p = 0.000). The median serum levels of CA 19-9 in group A and B were 46.0 U/mL and 19.1 U/mL, respectively (p = 0.005). The median serum level of CRP in group A was 1.2 g/dL, whereas it was 0.3 in group B (p = 0.000). ROC analysis showed that the optimal CA 125 cutoff value was 100.9 U/mL; the optimal CA 19-9 cutoff value was 27.7 U/mL; and the optimal CRP cutoff value was 1.0 g/dL. (4) Conclusions: Ruptured endometrioma can be diagnosed preoperatively using a combination of clinical symptoms, laboratory findings, and radiological findings. If a physician suspects a ruptured endometrioma, surgery should be performed to ensure optimal prognosis.

TGFBI as a candidate biomarker for non-invasive diagnosis of early-stage endometriosis

STUDY QUESTION

Can cartilage oligomeric matrix protein (COMP) and transforming growth factor-β-induced protein ig-h3 (TGFBI) alone or in combination with cancer antigen 125 (CA-125) be considered as potential blood biomarkers of endometriosis?

SUMMARY ANSWER

The results of this study indicate that COMP has no diagnostic value. TGFBI has potential as a non-invasive biomarker of the early stages of endometriosis, while TGFBI together with CA-125 has similar diagnostic characteristics as CA-125 alone for all stages of endometriosis.

WHAT IS KNOWN ALREADY

Endometriosis is a common, chronic gynecological disease that significantly affects patient quality of life by causing pain and infertility. The gold standard for diagnosis is visual inspection of pelvic organs by laparoscopy, therefore there is an urgent need for discovery of non-invasive biomarkers for endometriosis to reduce diagnostic delays and allow earlier treatment of patients. The potential biomarkers for endometriosis evaluated in this study (COMP and TGFBI) were previously identified by our proteomic analysis of peritoneal fluid samples.

STUDY DESIGN, SIZE, DURATION

This is a case-control study divided into a discovery (n = 56 patients) and a validation phase (n = 237 patients). All patients were treated between 2008 and 2019 in a tertiary medical center.

PARTICIPANTS/MATERIALS, SETTING, METHOD

Patients were stratified based on the laparoscopic findings. The discovery phase included 32 endometriosis patients (cases) and 24 patients with confirmed absence of endometriosis (controls). The validation phase included 166 endometriosis and 71 control patients. Concentrations of COMP and TGFBI were measured by ELISA in plasma samples, whereas concentration of CA-125 was measured using a clinically validated assay for serum samples. Statistical and receiver operating characteristic (ROC) curve analyses were performed. The classification models were built using the linear support vector machine (SVM) method with the SVM built-in feature ranking method.

MAIN RESULTS AND THE ROLE OF CHANCE

The discovery phase revealed significantly increased concentration of TGFBI, but not COMP, in plasma samples of patients with endometriosis compared to controls. In this smaller cohort, univariate ROC analysis showed fair diagnostic potential of TGFBI, with an AUC value of 0.77, sensitivity of 58%, and specificity of 84%. The classification model built using linear SVM and combining TGFBI and CA-125 showed an AUC value of 0.91, sensitivity of 88% and specificity of 75% in distinguishing patients with endometriosis from controls. The validation phase results revealed similar diagnostic characteristics of the SVM model combining TGFBI and CA-125, with an AUC value of 0.83, sensitivity of 83% and specificity of 67% and CA-125 alone with AUC value of 0.83, sensitivity of 73% and specificity of 80%. TGFBI exhibited good diagnostic potential for early-stage endometriosis (revised American Society for Reproductive Medicine stage I-II), with an AUC value of 0.74, sensitivity of 61% and specificity of 83% compared to CA-125, which had an AUC value of 0.63, sensitivity of 60% and specificity of 67%. An SVM model combining TGFBI and CA-125 showed a high AUC value of 0.94 and sensitivity of 95% for diagnosing moderate-to-severe endometriosis.

LIMITATIONS, REASONS FOR CAUTION

The diagnostic models were built and validated from a single endometriosis center, and thus further validation and technical verification in a multicenter study with a larger cohort is needed. Additional limitation was lack of histological confirmation of disease for some patients in the validation phase.

WIDER IMPLICATIONS OF THE FINDINGS

This study revealed for the first time increased concentration of TGFBI in plasma samples of patients with endometriosis, particularly those with minimal-to-mild endometriosis, compared to controls. This is the first step in considering TGFBI as a potential non-invasive biomarker for the early stages of endometriosis. It also opens a path for new basic research to investigate the importance of TGFBI in the pathophysiology of endometriosis. Further studies are needed to confirm the diagnostic potential of a model based on TGFBI and CA-125 for the non-invasive diagnosis of endometriosis.

STUDY FUNDING/COMPETING INTEREST(S)

The preparation of this manuscript was supported by grant J3-1755 from the Slovenian Research Agency to T.L.R and EU H2020-MSCA-RISE project TRENDO (grant 101008193). All authors declare that they have no conflicts of interest.

TRIAL REGISTRATION NUMBER

NCT0459154.

The effects of Rituximab on experimental endometriosis model in rats

AIM

Endometriosis is a common, chronic benign gynecologic disease and distresses women in their reproductive age. Yet the pathogenesis of endometriosis is not clear, multifactorial mechanisms have been characterized for the initiation, progression, and regression of this disease. It has been suggested that immune cells in the lymphoid lineage play essential roles in accepting or rejecting the survival, implantation, and proliferation of endometrial and endometriotic cells and, dysfunction of B-lymphocytes (B-cells) are one of the major causes for the progression of endometriosis. In this study, we aimed to evaluate the potential therapeutic efficacy of Rituximab, an inhibitor for B-cells, for endometriosis in an experimental animal model.

METHODS

Experimental endometriosis animal model has been utilized using mature female rats. Rats underwent surgery to initiate endometriosis on the abdominal wall. After confirming for endometriosis, rats were treated with either Rituximab or saline solution. After 14 days of treatment, implants were dissected, and evaluated for volumes and histological features. Anti-CD-20 antibody was used for immunohistochemistry scoring purposes.

RESULTS

There is significant decrease in the volume of endometriotic implants after treatment with Rituximab (188.81 ± 149.42 vs 20.37 ± 13.08, p = 0.001). There are also significant differences for the B-cell count and fibrosis score between the control and treatment groups (3.08 ± 2.6 vs 1.56 ± 1.42., p = 0.043).

CONCLUSION

In an experimental rat endometriosis model, we assessed Rituximab, an antibody for B-lymphocyte, as a candidate medical treatment for endometriosis. Additional studies are required to further evaluate the effects of Rituximab on the prevention of endometriosis.

Endometriosis and inflammatory immune responses: Indian experience

Endometriosis is a public health disorder affecting ∼ 247 million women globally and ∼ 42 million women in India. Women with endometriosis suffer from dysmenorrhea, chronic pelvic pain, dyspareunia, dyschezia, fatigue, depression, and infertility leading to significant socioeconomic impact and morbidity. The etiology of endometriosis is not understood well even after 100 years of research. Currently, there is no permanent cure for endometriosis. The inflammatory immune response is one of the important features of etiopathogenesis of endometriosis and therefore understanding the inflammatory immune response would lead to a better understanding of this enigmatic disorder and may also lead to biomarker discovery for diagnosis of endometriosis. We investigated the autoimmune etiology of endometriosis in the Indian population. Using the proteomics approach, anti-endometrial antibodies (AEAs) were detected in Indian women with endometriosis [anti-endometrial antibodies - tropomyosin 3 (TPM3), stomatin-like protein2 (SLP-2), and tropomodulin 3 (TMOD3)]. The studies on AEAs provided a better understanding of autoimmune mechanisms in endometriosis. All three subtypes of endometriosis; superficial peritoneal, ovarian endometrioma, and deep infiltrating endometriosis were reported in Indian women. In this review, we discuss our experiences of the inflammatory immune response, autoimmunity, comorbidities, and clinical phenotypes in women with endometriosis in India.

Gas Chromatography-Mass Spectrometry (GC-MS) Metabolites Analysis in Endometriosis Patients: A Prospective Observational Translational Study

BACKGROUND

Endometriosis affects women of reproductive age, and its pathogenesis is still unclear. Typically, it overlaps other similar medical and surgical conditions, determining a delay in early diagnosis. Metabolomics allows studying metabolic changes in different physiological or pathological states to discover new potential biomarkers. We used the gas chromatography-mass spectrometer (GC-MS) to explore metabolic alterations in endometriosis to better understand its pathophysiology and find new biomarkers.

METHODS

Twenty-two serum samples of patients with symptomatic endometriosis and ten without it were collected and subjected to GC-MS analysis. Multivariate and univariate statistical analyses were performed, followed by pathway analysis.

RESULTS

Partial least squares discriminant analysis was performed to determine the differences between the two groups (p = 0.003). Threonic acid, 3-hydroxybutyric acid, and proline increased significantly in endometriosis patients, while alanine and valine decreased. ROC curves were built to test the diagnostic power of metabolites. The pathway analysis identified the synthesis and degradation of ketone bodies and the biosynthesis of phenylalanine, tyrosine, and tryptophan as the most altered pathways.

CONCLUSIONS

The metabolomic approach identifies metabolic alterations in women with endometriosis. These findings may improve our understanding of the pathophysiological mechanisms of disease and the discovery of new biomarkers.

Gastroenterologist Primer: Endometriosis for Gastroenterologists

BACKGROUND AND AIM

A comprehensive understanding of endometriosis and its common gastrointestinal presentations are critical for gastroenterologists to ensure appropriate and timely screening and diagnosis. Endometriosis is a common inflammatory disease that frequently presents with gastrointestinal symptoms overlapping with irritable bowel syndrome (IBS) and other gastrointestinal disorders. Many endometriosis patients first present to a gastroenterologist or generalist, which may prolong the time to diagnosis and appropriate care.

METHOD AND RESULTS

This review describes the current literature on endometriosis presentation, overlap with gastrointestinal conditions, and standard diagnostic and treatment options for gastroenterologists to consider. For appropriate and swift treatment, gastroenterologists must consider an endometriosis diagnosis in females of menstruating age presenting with pain, bloating, altered stools, and non-gastrointestinal symptoms and refer patients for further evaluation.

Non-invasive diagnosis of endometriosis: Immunologic and genetic markers

Endometriosis, a benign gynecologic and chronic inflammatory disease, is defined by the presence of endometrial tissue outside the uterus characterized mainly by pelvic pain and infertility. Because endometriosis affects approximately 10% of females, it represents a significant socioeconomic burden worldwide having tremendous impact on daily quality of life. Accurate and prompt diagnosis is crucial for the management of this debilitating disorder. Unfortunately, diagnosis is typically delayed to lack of specific symptoms and readily accessible biomarkers. Although histopathologic examination remains the current gold standard, this approach is highly invasive and not applicable for early screening. Recent work has focused on the identification of reliable biomarkers including immunologic, ie, immune cells, antibodies and cytokines, as well as genetic and biochemical markers, ie, microRNAs, lncRNAs, circulating and mitochondrial nucleic acids, along with some hormones, glycoproteins and signaling molecules. Confirmatory research studies are, however, needed to more fully establish these markers in the diagnosis, progression and staging of these endometrial lesions.

Combined proteomics and transcriptomics identifies serpin family C member 1 associated protein as a biomarker of endometriosis

OBJECTIVE

To explore potential biomarkers indicating endometriosis (EM).

MATERIALS AND METHODS

A proteomics method and combined quantitative transcriptomics were adopted to highlight markers in the EM. Venn analysis was used to integrate the ribonucleic acid sequencing (RNA-seq) and protein profiles. Promising candidate markers were tested by enzyme-related immunosorbent assay.

RESULTS

A sum of 979 mRNAs and 39 proteins were tested to be significantly differentially expression in the standard cluster compared with the EM cluster. Venn analysis showed a filtered signature of only two down-regulated molecules in the EM group, i.e. fetuin B (FETUB) and serpin family C member 1 (SERPINC1); the latter showed a big variance between the control category and the EM set in the authentication test.

CONCLUSION

SERPINC1 may be a useful possible biomarker for the analysis of EM.

Seven days of statin treatment improves nitric-oxide mediated endothelial-dependent cutaneous microvascular function in women with endometriosis

INTRODUCTION

Endometriosis is associated with systemic inflammation and increased risk of cardiovascular disease (CVD). Endothelial dysfunction is one of the first manifestations of CVD but is unexplored in women with endometriosis. HMG-CoA-reductase inhibitors (statins) exert potent anti-inflammatory effects, and have been proposed as an adjunctive therapy in women with endometriosis. We hypothesized that microvascular endothelial function would be impaired in otherwise healthy women with endometriosis mediated by reduced nitric oxide (NO)-dependent dilation and that short term statin administration would improve endothelial function.

METHODS

In 8 healthy control (HC: 33 ± 9 yr) and 8 women with endometriosis (EN: 34 ± 9 yr), laser-Doppler flux (LDF) was measured continuously during graded intradermal microdialysis perfusion of the endothelium-dependent agonist acetylcholine (Ach: 10-10-10-1 M) alone and in combination with the NO synthase inhibitor (L-NAME: 0.015 M). 6 EN repeated the microdialysis experiment following 7 days of oral atorvastatin treatment (10 mg). Cutaneous vascular conductance was calculated (CVC = LDF*mmHg-1) and normalized to site-specific maximum (28 mM sodium nitroprusside, 43 °C). The NO-dependent dilation was calculated as the difference between the areas under the dose response curves.

RESULTS

Ach-induced vasodilation was blunted in women with endometriosis (main effect p < 0.01), indicating impaired endothelial function. NO-dependent vasodilation was also reduced in women with endometriosis (HC: 217 ± 120.3 AUC vs. EN: 88 ± 97 AUC, p = 0.03). Oral atorvastatin improved Ach-induced (main effect p < 0.01) and NO-dependent (295 ± 153 AUC; p = 0.05) vasodilation in women with endometriosis.

CONCLUSION

Microcirculatory endothelium-dependent vasodilation is impaired in women with endometriosis, mediated in part by reductions in NO. Short-term oral atorvastatin improved endothelium-dependent vasodilation, suggesting that statin therapy may be a viable intervention strategy to mitigate accelerated CVD risk in women with endometriosis.

Interferon Signaling in the Endometrium and in Endometriosis

Endometriosis is an estrogen-dependent inflammatory disease that develops in reproductive-aged women who experience pelvic pain and infertility. Even though endometriosis is not a new disease, its molecular etiology has not been clearly elucidated. Defects in the immune system might be one of the factors that promote endometriosis progression. For example, elevated levels of proinflammatory cytokines are associated with endometriosis. Interferon is one of the cytokines that is elevated in endometriotic tissues compared with normal endometrium. Therefore, high interferon levels play a crucial role in endometriosis progression. In addition to endometriosis, however, interferon has a critical role in endometrial function, particularly in the initiation and maintenance of pregnancy. Therefore, this review describes the double-edged sword of interferon signaling in normal endometrial function versus endometriosis progression and also discusses interferon targeting as a new nonhormonal therapy for endometriosis. This approach may increase the efficacy of endometriosis treatment and reduce the adverse effects associated with current hormonal therapy for this disease.

Comparison of Morphological and Digital-Assisted Analysis for BCL6 Endometrial Expression in Women with Endometriosis

BCL6 (B-cell lymphoma 6) is a proto-oncogene and transcriptional repressor initially described as being involved in B-cell lymphoma. Recently, this factor has been identified as a promising tissue biomarker which could be used to diagnose women affected by endometriosis. Previous studies used HSCORE for BCL6 staining quantification in the endometrium. However, this semi-quantitative technique of analysis has some limitations, including a lack of objectivity, robustness, and reproducibility that may lead to intra- and inter-observer variability. Our main goal was to develop an original computer-assisted method to quantify BCL6 staining from whole-slide images reliably. In order to test the efficiency of our new digital method of quantification, we compared endometrial BCL6 expression between fertile and infertile women without or with different stages of endometriosis by using the widely used HSCORE analysis and our new automatic digital image analysis. We find a higher expression of BCL6 in the endometrium of infertile women with endometriosis and women with stage IV endometriosis. Furthermore, we demonstrate a significant correlation between the two types of independent measurements, indicating the robustness of results and also the reliability of our computer-assisted method for BCL6 quantification. In conclusion, our work, by using this original computer-assisted method, enables BCL6 quantification more objectively, reliably, robustly, and promptly compared to HSCORE analysis.

Analysis of Long Non-Coding RNA (lncRNA) UCA1, MALAT1, TC0101441, and H19 Expression in Endometriosis

Endometriosis is a disease of complex etiology. Hormonal, immunological, and environmental factors are involved in its formation. In recent years, special attention has been paid to genetic mechanisms that can have a significant impact on the increased incidence of endometriosis. The study aimed to analyze the expression of four long non-coding RNA (lncRNA) genes, UCA1, MALAT1, TC0101441, and H19, in the context of the risk of developing endometriosis. The material for genetic testing for the expression of lncRNA genes were tissue slices embedded in paraffin blocks from patients with endometriosis (n = 100) and the control group (n = 100). Gene expression was determined by the RT-PCR technique. The expression of the H19 gene in endometriosis patients was statistically significantly lower than in the control group. A statistically significant association was found between H19 gene expression in relation to The Revised American Society for Reproductive Medicine classification of endometriosis (rASRM) in the group of patients with endometriosis. Research suggests that H19 expression plays an important role in the pathogenesis of endometriosis.

The role of some inflammatory markers, cytokins and tumor markers in diagnosis of endometriosis

Endometriosis is a multifactorial disease which etiopathogenesis has not been elucidated. One of the theories of etiopathogenesis is the inflammatory theory. Aims of the study: To develop a practical non-invasive test for the diagnosis of endometriosis by examining some inflammatory markers and cytokines; to compare the highly sensitive C-reactive protein (hsCRP), cytokines (interleukin-6-IL-6 and tumor necrotizing factor alpha) and the tumor marker cancer antigen 125 (CA-125) among healthy patients and patients with endometriosis; to determine the sensitivity and specificity of each biomarker separately in the diagnosis of endometriosis and to determine their role in the diagnosis of endometriosis. Materials and methods: In a prospective study conducted at the University Clinic for Gynecology and Obstetrics, Ss. Cyril and Methodius University in Skopje, North Macedonia 138 patients were included of a reproductive age between 18-50 years (83 with diagnosis endometriosis operated laparoscopically or with laparotomy) and a control group of 55 healthy women, in a period between 01.09.2018 to 01.05.2021. Serum levels of IL-6, TNF-α, hs-CRP and tumor marker CA-125 were evaluated in both groups. Results: Serum levels of CA-125, IL-6 and TNF-α and hs-CRP were significantly higher in patients with endometriosis compared to the control group. The surface under the ROC curve (AUC) for IL-6, CA-125, hs-CRP, and TNF-α has shown that as individual markers they all have a discriminatory capacity to diagnose patients with endometriosis. Conclusions: Results obtained in our study showed statistically significantly higher serum concentrations of CA-125, IL-6 and TNF-α and hs-CRP in patients with endometriosis compared to the control group of patients. However, none of these biomarkers showed a high sensitivity for diagnosis of endometriosis. It is necessary to find a panel combination of biomarkers with a high sensitivity of about 100% that will enable early diagnosis of endometriosis.

Endometriosis biomarkers of the disease: an update

PURPOSE OF REVIEW

Endometriosis is a complex benign gynaecologic condition with heterogenous presentations and a large impact on the global healthcare system and on the quality of life for millions of women. Currently, the gold standard for diagnosis involves direct visualization of lesions during surgery confirmed by histopathological diagnosis, resulting in an average delay in its initial diagnosis of 8-10 years. Therefore, the search for noninvasive diagnostic testing options has been subject to a large body of research.

RECENT FINDINGS

Multiple potential biomarkers have been explored for noninvasive testing for endometriosis, including glycoproteins, inflammatory cytokines, immunological molecules, angiogenesis markers, hormones, micro RNAs (miRNAs), proteomics, metabolomics, genomics and the microbiome.

SUMMARY

Although there are challenges to consider, areas for real promise and advancement in the noninvasive diagnosis of endometriosis are currently being explored with real promise in the area of miRNAs, proteomics, metabolomics, genomics and the microbiome.

Quantitative label-free proteomic analysis of human follicle fluid to identify novel candidate protein biomarker for endometriosis-associated infertility

BACKGROUND

Endometriosis (EM) leads to a decline in fertility, which is characterized by a decrease in the number and quality of follicles, and thus has a negative impact on in vitro fertilization (IVF) outcomes. However, the mechanism of how EM affects oocytes and leads to infertility remains unclear. As a potentially available sample directly related to oocyte growth, follicular fluid (FF) has important research value. Evaluating the association of FF content and EM-associated infertility through proteomics may helpful to explore the possible pathogenesis of EM-associated infertility.

METHODS

In the present experimental study, from August 2019 to June 2020, FF samples were obtained as control group (CON-G; n = 10) from women with no one female factor of infertility and were undergoing IVF due to other reasons, 20 women with EM-associated infertility undergoing IVF with no other female factors were distributed into the EM group according to the time for IVF: (i) EM-group 1 (EM-G1, Stage I to Stage III, n = 10); (ii) EM-group 2 (EM-G2, Stage I to Stage III, n = 10). label-free quantitative proteomics (LFQP) technology and parallel reaction monitoring (PRM) approach were combined to aid in identifying and validating FF protein biomarkers for EM-associated infertility. In PRM analysis, another 20 subjects were enrolled as EM-associated infertility group (EM,Stage I to Stage III, n = 10) and controls (CON, n = 10) within the same time and inclusion criteria are the same as previously described. Finally, a potential protein biomarker panel of FF differential expressed proteins to EM-associated infertility was also evaluated by t-test and receiver operating characteristic (ROC) curve and binary Logistic regression models.

RESULTS

7 significant differential expressed proteins which closely related to EM-associated infertility were found by LFQP technology, among which immunoglobulin lambda variable 7-46 (IGLV7-46), Immunoglobulin heavy constant gamma 2 (IGHG2), glia-derived nexin (GDN) and Inter-alpha-trypsin inhibitor heavy chain H3 (ITIH3) were significantly up-regulated (p < 0.05), while corticosteroid-binding globulin (CBG), angiotensinogen (AGT) and Fetuin-B (FETUB) were significantly down regulated (p < 0.05). Additionally, GDN and AGT was identified as a potential protein biomarker by further PRM analysis for EM-associated infertility according to ROC curve analysis and t-test (p < 0.05), the area under the curve (AUC) for GDN and AGT was 0.78 and 0.69 with optimum sensitivity of 50%, 70% and specificity of 100%, 90%, respectively. According to binary logistic regression and evaluated ROC analysis, the AUC for the combination of GDN and AGT was 0.80.

CONCLUSIONS

To the best of our knowledge, this is the first time that elevated GDN protein levels have been found in the FF of patients with EM-associated infertility. Combining LFQP technology and PRM method we found the abnormal of GDN and AGT in FF may be the potential cause of EM-associated infertility which may help to better understand the physiological and pathological mechanism of EM-associated infertility. Further experimental studies are required to confirm their mechanism in EM-associated infertility. The results of this study are also consistent with the previous conclusion that EM is a chronic inflammatory disease.

SIGNIFICANCE

To the best of our knowledge, this is the first time that elevated GDN protein levels have been found in the follicular fluid of patients with EM-associated infertility. Combining LFQP technology and PRM methods we found the abnormal of GDN and AGT protein in FF may be the potential cause of EM-associated infertility which may help to better understand the physiological and pathological mechanism of EM-associated infertility. Clinically, it has been recognized that EM is related to infertility, but the mechanism remains unclear. Our study combines label-free quantitative proteomics technology and parallel reaction monitoring methods to identify and verify the FF protein biomarkers of EM-associated infertility, which provides a good research method for follow-up research.

Platelet-to-Lymphocyte Ratio and CA125 Level as a Combined Biomarker for Diagnosing Endometriosis and Predicting Pelvic Adhesion Severity

Adhesion is a significant biological characteristic of endometriosis, and accurate evaluation of the pelvic adhesion is necessary for surgical treatment. Serum CA125 is yet the most common used biomarker in the diagnosis and follow-up of patients with endometriosis despite of its high false-positive rate and low specificity. Herein, we aimed to examine the diagnostic value of the combination of the platelet-to-lymphocyte ratio (PLR) and CA125 for patients with different stages of endometriosis and their correlations with pelvic adhesion. We retrospectively analyzed the clinical data and blood count parameters of patients with both endometriosis and other benign ovarian tumors. The mean level of CA125, the PLR and the combined marker (the CA125 level multiplied by the PLR) in the EMs group were significantly higher than those in the Cyst group (P < 0.05). ROC curve analysis was used to compare the diagnostic values of serum PLR, CA125, and the combined marker in ovarian endometriosis. The cut-off value of the PLR was 176.835, with 28.3% sensitivity and 96.9% specificity. The cut-off value of CA125 was 31.67 U/mL, with 84.1% sensitivity and 87.4% specificity. The cut-off value of the combined marker was 3894.97, with 83.4% sensitivity and 95.8% specificity. It was found that the severity of adhesion in endometriosis was positively correlated with the PLR (r = 0.286, P < 0.01), CA125 (r = 0.276, P < 0.01), and combined marker (r = 0.369, P < 0.01). The combined marker showed the highest AUC value (0.751, 95% CI: 0.666–0.837), with a sensitivity of 56.0% and a specificity of 89.6%, and the cut-off value was 9056.94. Besides, the levels of CA125, PLR, and their combination were significantly elevated in patients with endometriosis. The combined marker was not only positively correlated with pelvic adhesion but also showed a greater diagnostic value and specificity than CA125 alone. These findings indicate that the combined marker may be a potential inflammatory biomarker playing an important role in the diagnosis and assessment of adhesion in endometriosis.

Evaluation of Soluble CD90: Potential for Diagnostic Significance in Endometriosis Patients

Background

Endometriosis is a chronic and debilitating gynecologic disorder, driven by endocrine and immune dysfunctions, which lead to poor endometrial differentiation and attenuated fertility. Escape from immune surveillance and involvement of inflammatory mechanisms appear to be factors in disease progression. Current diagnostic guidelines for endometriosis still lack an efficient biomarker. Here, we report a study on two previously unexplored factors as potential biomarkers for endometriosis.

Methods

A case-control study was performed to evaluate the diagnostic potential of serum CD90 and CD83 levels in endometriosis patients (cases validated by surgical and histological examination) compared to healthy controls. Serum was collected from age-matched females and analyzed by ELISA.

Results

Comparison of endometriosis patients to the control group showed significantly elevated levels of serum CD90 (1160 ± 856 pg/mL vs. 334 ± 228 pg/mL; ^∗∗∗∗p < 0.0001). A threshold value of 479.4 pg/mL was defined based on the control results, and the diagnostic efficiency of the test was estimated. The obtained sensitivity (70.4%), specificity (92.9%), positive predictive value (90.5%), and negative predictive value (76.5%) rated the test as one with promising diagnostic potential. In contrast, the analysis of serum CD83 levels showed comparable values in both groups, suggesting no association with patient status.

Conclusion

Elevated soluble CD90 in human serum is associated with endometriosis, which suggests its putative clinical significance as a biomarker in screening and/or diagnosis of the disease.

Antibody Arrays Identified Cycle-Dependent Plasma Biomarker Candidates of Peritoneal Endometriosis

Endometriosis is an estrogen-dependent inflammatory disease affecting women in their reproductive age. Due to non-specific symptoms, women with endometriosis are often misdiagnosed or are accurately diagnosed only after several years. Diagnosis of peritoneal endometriosis is especially challenging and relies only on laparoscopic surgery. To date, different molecules have been proposed as potential non-invasive biomarkers of endometriosis; however, none have been confirmed as clinically useful. Therefore, this study aimed to discover novel plasma biomarker candidates for peritoneal endometriosis using an antibody array platform. This study included patients with endometriosis-like symptoms characterized by the absence (controls) or presence of peritoneal endometriosis (cases) after laparoscopic surgery and histological evaluation. Patients were further divided into secretory and proliferative groups, according to the phase of their menstrual cycle. Their plasma samples were collected and analyzed on an antibody array platform targeting more than 1350 proteins with over 1820 antibodies. In the proliferative group, the analysis revealed three differential proteins between cases and controls: ITB3, ITA2B2, and ACVL-1. In the secretory group, none of the examined proteins reached the log-fold change (logFC) and significance thresholds simultaneously. The potential of the identified differential proteins as plasma biomarker candidates for peritoneal endometriosis should be evaluated on a larger cohort, and their role in endometriosis should be investigated in further studies.

Impacts of endocrine disrupting chemicals on reproduction in wildlife and humans

Endocrine disrupting chemicals (EDCs) are ubiquitous in aquatic and terrestrial environments. The main objective of this review was to summarize the current knowledge of the impacts of EDCs on reproductive success in wildlife and humans. The examples selected often include a retrospective assessment of the knowledge of reproductive impacts over time to discern how the effects of EDCs have changed over the last several decades. Collectively, the evidence summarized here within reinforce the concept that reproduction in wildlife and humans is negatively impacted by anthropogenic chemicals, with several altering endocrine system function. These observations of chemicals interfering with different aspects of the reproductive endocrine axis are particularly pronounced for aquatic species and are often corroborated by laboratory-based experiments (i.e. fish, amphibians, birds). Noteworthy, many of these same indicators are also observed in epidemiological studies in mammalian wildlife and humans. Given the vast array of reproductive strategies used by animals, it is perhaps not surprising that no single disrupted target is predictive of reproductive effects. Nevertheless, there are some general features of the endocrine control of reproduction, and in particular, the critical role that steroid hormones play in these processes that confer a high degree of susceptibility to environmental chemicals. New research is needed on the implications of chemical exposures during development and the potential for long-term reproductive effects. Future emphasis on field-based observations that can form the basis of more deliberate, extensive, and long-term population level studies to monitor contaminant effects, including adverse effects on the endocrine system, are key to addressing these knowledge gaps.

Elevated Circulatory Proline to Glutamine Ratio (PQR) in Endometriosis and Its Potential as a Diagnostic Biomarker

Endometriosis (EM) is a hormone-dependent gynecological disease associated with chronic pelvic pain and altered immuno-inflammatory processes. It shares some cancer-like characteristics such as increased proline biosynthesis and activated glutaminolysis. Both proline and glutamine are interconvertible metabolically, and studies have shown their roles in cancer cell metabolic reprogramming, redox homeostasis, occurrence/development of endometrial carcinoma, and its further progression toward the malignant state. So based on this, we hypothesized that the circulatory proline to glutamine ratio (PQR) would be altered in EM and may serve as an indicative biomarker to improve the clinical diagnosis of EM. In present study, the circulatory-PQR levels were estimated for 39 EM patients and 48 age matched healthy female subjects using 800 MHz NMR spectroscopy. Among 39 EM patients, 15 were in the clinical stages I to II and referred to here as moderate EM (MEM) patients and 24 were in the clinical stages III to IV and referred here as severe EM (SEM) patients. The circulatory-PQR levels were significantly increased in EM patients (0.99 ± 0.13 μM in MEM; 1.39 ± 0.22 μM in SEM) compared to normal control (NC) subjects (0.52 ± 0.05 μM in NC). Further, the circulatory PQR levels exhibit the highest diagnostic potential with area under receiver operating characteristic (AUROC) curve values equal to 0.87 ± 0.04 [95%CI = 0.79-0.96] for MEM and 0.89 ± 0.04 [95% CI = 0.82-0.96] for SEM. These results suggested that circulatory-PQR has significant potential to serve as a noninvasive biomarker for diagnostic/prognostic screening of EM and further underscored the importance of these two nonessential amino acids (proline and glutamine) in cancer metabolism.

[Mystery of endometriosis - catamenial pneumothorax]

The review is devoted to clinical picture, main theories of pathogenesis, traditional and innovative methods of diagnosis and surgical treatment of catamenial pneumothorax. Currently, clinicians prefer magnetic resonance imaging and thoracoscopy for diagnosis of this disease. Various researchers are actively searching for laboratory diagnostic methods that can confirm endometrioid nature of pneumothorax. Treatment and prevention of catamenial pneumothorax are a controversial issue depending both clinical picture and preferences of the attending physician. Currently, the majority of authors believe that hormonal therapy combined with diaphragm resection ensures optimal anti-relapse effect in patients with thoracic endometriosis.

ESHRE guideline: endometriosis

STUDY QUESTION

How should endometriosis be diagnosed and managed based on the best available evidence from published literature?

SUMMARY ANSWER

The current guideline provides 109 recommendations on diagnosis, treatments for pain and infertility, management of disease recurrence, asymptomatic or extrapelvic disease, endometriosis in adolescents and postmenopausal women, prevention and the association with cancer.

WHAT IS KNOWN ALREADY

Endometriosis is a chronic condition with a plethora of presentations in terms of not only the occurrence of lesions, but also the presence of signs and symptoms. The most important symptoms include pain and infertility.

STUDY DESIGN SIZE DURATION

The guideline was developed according to the structured methodology for development of ESHRE guidelines. After formulation of key questions by a group of experts, literature searches and assessments were performed. Papers published up to 1 December 2020 and written in English were included in the literature review.

PARTICIPANTS/MATERIALS SETTING METHODS

Based on the collected evidence, recommendations were formulated and discussed within specialist subgroups and then presented to the core guideline development group (GDG) until consensus was reached. A stakeholder review was organized after finalization of the draft. The final version was approved by the GDG and the ESHRE Executive Committee.

MAIN RESULTS AND THE ROLE OF CHANCE

This guideline aims to help clinicians to apply best care for women with endometriosis. Although studies mostly focus on women of reproductive age, the guideline also addresses endometriosis in adolescents and postmenopausal women. The guideline outlines the diagnostic process for endometriosis, which challenges laparoscopy and histology as gold standard diagnostic tests. The options for treatment of endometriosis-associated pain symptoms include analgesics, medical treatments and surgery. Non-pharmacological treatments are also discussed. For management of endometriosis-associated infertility, surgical treatment and/or medically assisted reproduction are feasible. While most of the more recent studies confirm previous ESHRE recommendations, there are five topics in which significant changes to recommendations were required and changes in clinical practice are to be expected.

LIMITATIONS REASONS FOR CAUTION

The guideline describes different management options but, based on existing evidence, no firm recommendations could be formulated on the most appropriate treatments. Also, for specific clinical issues, such as asymptomatic endometriosis or extrapelvic endometriosis, the evidence is too scarce to make evidence-based recommendations.

WIDER IMPLICATIONS OF THE FINDINGS

The guideline provides clinicians with clear advice on best practice in endometriosis care, based on the best evidence currently available. In addition, a list of research recommendations is provided to stimulate further studies in endometriosis.

STUDY FUNDING/COMPETING INTERESTS

The guideline was developed and funded by ESHRE, covering expenses associated with the guideline meetings, with the literature searches and with the dissemination of the guideline. The guideline group members did not receive payments. C.M.B. reports grants from Bayer Healthcare and the European Commission; Participation on a Data Safety Monitoring Board or Advisory Board with ObsEva (Data Safety Monitoring Group) and Myovant (Scientific Advisory Group). A.B. reports grants from FEMaLE executive board member and European Commission Horizon 2020 grant; consulting fees from Ethicon Endo Surgery, Medtronic; honoraria for lectures from Ethicon; and support for meeting attendance from Gedeon Richter; A.H. reports grants from MRC, NIHR, CSO, Roche Diagnostics, Astra Zeneca, Ferring; Consulting fees from Roche Diagnostics, Nordic Pharma, Chugai and Benevolent Al Bio Limited all paid to the institution; a pending patent on Serum endometriosis biomarker; he is also Chair of TSC for STOP-OHSS and CERM trials. O.H. reports consulting fees and speaker's fees from Gedeon Richter and Bayer AG; support for attending meetings from Gedeon-Richter, and leadership roles at the Finnish Society for Obstetrics and Gynecology and the Nordic federation of the societies of obstetrics and gynecology. L.K. reports consulting fees from Gedeon Richter, AstraZeneca, Novartis, Dr KADE/Besins, Palleos Healthcare, Roche, Mithra; honoraria for lectures from Gedeon Richter, AstraZeneca, Novartis, Dr KADE/Besins, Palleos Healthcare, Roche, Mithra; support for attending meetings from Gedeon Richter, AstraZeneca, Novartis, Dr KADE/Besins, Palleos Healthcare, Roche, Mithra; he also has a leadership role in the German Society of Gynecological Endocrinology (DGGEF). M.K. reports grants from French Foundation for Medical Research (FRM), Australian Ministry of Health, Medical Research Future Fund and French National Cancer Institute; support for meeting attendance from European Society for Gynaecological Endoscopy (ESGE), European Congress on Endometriosis (EEC) and ESHRE; She is an advisory Board Member, FEMaLe Project (Finding Endometriosis Using Machine Learning), Scientific Committee Chair for the French Foundation for Research on Endometriosis and Scientific Committee Chair for the ComPaRe-Endometriosis cohort. A.N. reports grants from Merck SA and Ferring; speaker fees from Merck SA and Ferring; support for meeting attendance from Merck SA; Participation on a Data Safety Monitoring Board or Advisory Board with Nordic Pharma and Merck SA; she also is a board member of medical advisory board, Endometriosis Society, the Netherlands (patients advocacy group) and an executive board member of the World Endometriosis Society. E.S. reports grants from National Institute for Health Research UK, Rosetrees Trust, Barts and the London Charity; Royalties from De Gruyter (book editor); consulting fees from Hologic; speakers fees from Hologic, Johnson & Johnson, Medtronic, Intuitive, Olympus and Karl Storz; Participation in the Medicines for Women's Health Expert Advisory Group with Medicines and Healthcare Products Regulatory Agency (MHRA); he is also Ambassador for the World Endometriosis Society. C.T. reports grants from Merck SA; Consulting fees from Gedeon Richter, Nordic Pharma and Merck SA; speaker fees from Merck SA, all paid to the institution; and support for meeting attendance from Ferring, Gedeon Richter and Merck SA. The other authors have no conflicts of interest to declare.

DISCLAIMER

This guideline represents the views of ESHRE, which were achieved after careful consideration of the scientific evidence available at the time of preparation. In the absence of scientific evidence on certain aspects, a consensus between the relevant ESHRE stakeholders has been obtained. Adherence to these clinical practice guidelines does not guarantee a successful or specific outcome, nor does it establish a standard of care. Clinical practice guidelines do not replace the need for application of clinical judgement to each individual presentation, nor variations based on locality and facility type. ESHRE makes no warranty, express or implied, regarding the clinical practice guidelines and specifically excludes any warranties of merchantability and fitness for a particular use or purpose (Full disclaimer available at www.eshre.eu/guidelines.).

The Eutopic Endometrium Proteome in Endometriosis Reveals Candidate Markers and Molecular Mechanisms of Physiopathology

Endometriosis is a common chronic gynaecological disease causing various symptoms, such as infertility and chronic pain. The gold standard for its diagnosis is still laparoscopy and the biopsy of endometriotic lesions. Here, we aimed to compare the eutopic endometrium from women with or without endometriosis to identify proteins that may be considered as potential biomarker candidates. Eutopic endometrium was collected from patients with endometriosis (n = 4) and women without endometriosis (n = 5) during a laparoscopy surgery during the mid-secretory phase of their menstrual cycle. Total proteins from tissues were extracted and digested before LC-MS-MS analysis. Among the 5301 proteins identified, 543 were differentially expressed and enriched in two specific KEGG pathways: focal adhesion and PI3K/AKT signaling. Integration of our data with a large-scale proteomics dataset allowed us to highlight 11 proteins that share the same trend of dysregulation in eutopic endometrium, regardless of the phase of the menstrual cycle. Our results constitute the first step towards the identification of potential promising endometrial diagnostic biomarkers. They provide new insights into the mechanisms underlying endometriosis and its etiology. Our results await further confirmation on a larger sample cohort.

Endometriosis and adverse pregnancy outcome

INTRODUCTION

Endometriosis is a gynecologic disease affecting approximately 10% of reproductive age women, around 21-47% of women presenting subfertility and 71-87% of women with chronic pelvic pain. Main symptoms are chronic pelvic pain, dysmenorrhea, dyspareunia and infertility that seem to be well controlled by oral contraceptive pill, progestogens, GnRh antagonists. The aim of this review was to illustrate the modern diagnosis of endometriosis during pregnancy, to evaluate the evolution of endometriotic lesions during pregnancy and the incidence of adverse outcomes.

EVIDENCE ACQUISITION

Published literature was retrieved through searches of the database PubMed (National Center for Biotechnology Information, US National Library of Medicine, Bethesda, MD, USA). We searched for all original articles published in English through April 2020 and decided to extract every notable information for potential inclusion in this review. The search included the following MeSH search terms, alone or in combination: "endometriosis" combined with "endometrioma," "biomarkers," "complications," "bowel," "urinary tract," "uterine rupture," "spontaneous hemoperitoneum in pregnancy" and more "adverse pregnancy outcome," "preterm birth," "miscarriage," "abruption placentae," "placenta previa," "hypertensive disorder," "preeclampsia," "fetal grow restriction," "small for gestation age," "cesarean delivery."

EVIDENCE SYNTHESIS

Pregnancy in women with endometriosis does not always lead to disappearance of symptoms and decrease in the size of endometriotic lesions, but it may be possible to observe a malignant transformation of ovarian endometriotic lesions. Onset of complications may be caused by many factors: chronic inflammation, adhesions, progesterone resistance and a dysregulation of genes involved in the embryo implantation. As results, the pregnancy can be more difficult because of endometriosis related complications (spontaneous hemoperitoneum [SH], bowel complications, etc.) or adverse outcomes like preterm birth, FGR, hypertensive disorders, obstetrics hemorrhages (placenta previa, abruptio placenta), miscarriage or cesarean section. Due to insufficient knowledge about its pathogenesis, currently literature data are contradictory and do not show a strong correlation between endometriosis and these complications except for miscarriage and cesarean delivery.

CONCLUSIONS

Future research should focus on the potential biological pathways underlying these relationships in order to inform patients planning a birth about possible complications during pregnancy.

Endometriosis, Psoriasis, and Psoriatic Arthritis: A Prospective Cohort Study

Endometriosis, psoriasis, and psoriatic arthritis (PsA) are chronic inflammatory disorders whose etiologies remain poorly understood but may be correlated, as endometriosis has been associated with other inflammatory disorders. We investigated the bidirectional associations between laparoscopically confirmed endometriosis and physician-diagnosed psoriasis and PsA in the Nurses' Health Study II cohort (n = 116,429, United States, 1991-2013). We confirmed 4,112 incident cases of laparoscopically confirmed endometriosis (mean age at diagnosis = 40.3 years) and 697 validated physician-diagnosed cases of psoriasis (mean age at diagnosis = 43.6 years), 110 of which presented with concomitant PsA. A history of psoriasis with concomitant PsA was associated with a 2-fold higher risk of endometriosis (hazard ratio (HR) = 2.01, 95% CI: 1.23, 3.30); however, no association was observed between psoriasis without PsA and endometriosis risk (HR = 0.93, 95% CI: 0.68, 1.26). When endometriosis was the exposure, it was not associated with a risk of subsequent psoriasis (HR = 1.28, 95% CI: 0.95, 1.72). The risk of psoriasis with PsA was notably higher; however, the sample size was small and the confidence intervals wide (HR = 1.77, 95% CI: 0.89, 3.52). Our findings suggest that psoriasis with concomitant PsA is associated with greater risk of laparoscopically confirmed endometriosis. In addition, there was a suggestive association between endometriosis diagnosis and subsequent risk of psoriasis with PsA.

Letrozole promotes the expression of integrin αvβ3 and HOXA10 in endometrium of endometriosis

Endometriosis is a common estrogen-dependent chronic inflammatory disease that leads to infertility in women of reproductive age. Perhaps infertility reflects the reduced expression of integrin αvβ3 and HOXA10 in endometriosis. Previous studies have shown that administration of letrozole, a non-steroidal aromatase inhibitor for cancer treatment, increased the clinical pregnancy rate in women with endometriosis, but the mechanisms remain to be determined. In this communication, a rat model of endometriosis was established. Animals were treated with letrozole at 2ug/kg of body weight, intragastric administration for 15 consecutive days. Letrozole increased the expression of αvβ3 and HOXA10 in the endometriosis model and endometrial receptivity.Abbreviations: WOI: window of implantation; RGD: Arg-Gly-Asp; HOX: homeobox; E2: estradiol; SPF: specific pathogen-free.

Gut Microbiota Exceeds Cervical Microbiota for Early Diagnosis of Endometriosis

The diagnosis of endometriosis is typically delayed by years for the unexclusive symptom and the traumatic diagnostic method. Several studies have demonstrated that gut microbiota and cervical mucus potentially can be used as auxiliary diagnostic biomarkers. However, none of the previous studies has compared the robustness of endometriosis classifiers based on microbiota of different body sites or demonstrated the correlation among microbiota of gut, cervical mucus, and peritoneal fluid of endometriosis, searching for alternative diagnostic approaches. Herein, we enrolled 41 women (control, n = 20; endometriosis, n = 21) and collected 122 well-matched samples, derived from feces, cervical mucus, and peritoneal fluid, to explore the nature of microbiome of endometriosis patients. Our results indicated that microbial composition is remarkably distinguished between three body sites, with 19 overlapped taxa. Moreover, endometriosis patients harbor distinct microbial communities versus control group especially in feces and peritoneal fluid, with increased abundance of pathogens in peritoneal fluid and depletion of protective microbes in feces. Particularly, genera of Ruminococcus and Pseudomonas were identified as potential biomarkers in gut and peritoneal fluid, respectively. Furthermore, novel endometriosis classifiers were constructed based on taxa selected by a robust machine learning method. These results demonstrated that gut microbiota exceeds cervical microbiota in diagnosing endometriosis. Collectively, this study reveals important insights into the microbial profiling in different body sites of endometriosis, which warrant future exploration into the role of microbiota in endometriosis and highlighted values on gut microbiota in early diagnosis of endometriosis.

A critical appraisal of the circulating levels of differentially expressed microRNA in endometriosis†

Endometriosis is a common gynecological condition characterized by estrogen dependence, chronic pelvic pain, infertility, and diagnostic delay of between 5.4 and 12 years. Despite extensive study, no biomarker, either alone or in combination with other markers, has proven superior to laparoscopy for the diagnosis of endometriosis. Recent studies report that circulating levels of differentially expressed microRNA (miRNA) in women with endometriosis compared with controls are potential diagnostic tools. However, the lack of replication and absence of validated differential expression in novel study populations have led some to question the diagnostic value of miRNA. To elucidate potential reasons for the lack of replication of study results and explore future directions to enhance replicability of circulating miRNA results, we carried out an electronic search of the miRNA literature published between 2000 and 2020. Eighteen studies were identified in which 63 different miRNAs were differentially expressed in the circulation of women with endometriosis compared with controls. However, the differential expressions of only 14 miRNAs were duplicated in one or more studies. While individual miRNAs lacked diagnostic value, miRNA panels yielded sensitivity and specificity equal to or better than laparoscopy in five studies. Important differences in study design, sample processing, and analytical methods were identified rendering direct comparisons across studies problematic and could account for the lack of reproducibility of study results. We conclude that while the results of miRNA studies to date are encouraging, refinements to study design and analytical methods should enhance the reliability of circulating miRNA for the diagnosis of endometriosis.

Brief Review of Endometriosis and the Role of Trace Elements

Endometriosis is a chronic, estrogen-dependent, inflammatory condition that is defined as the presence of endometrial glands and stroma outside the uterine cavity. Despite the progress in research into the mechanisms leading to the development of endometriosis, its cause has not yet been established. It seems to be possible that the formation of oxidative stress may be one of the main causes of the development of endometriosis. There is much research that studies the potential role of trace elements in the appearance of endometrial-like lesions. Most studies focus on assessing the content of selected trace elements in the blood, urine, or peritoneal fluid in women with endometriosis. Meanwhile, little is known about the content of these elements in endometrial-like implants, which may be helpful in developing the theory of endometriosis. Investigations that are more comprehensive are needed to confirm a hypothesis that some trace elements play a role in the pathomechanism of endometriosis.

Endometriosis: Epidemiology, Classification, Pathogenesis, Treatment and Genetics (Review of Literature)

Endometriosis is a “mysterious” disease and its exact cause has not yet been established. Among the etiological factors, congenital, environmental, epigenetic, autoimmune and allergic factors are listed. It is believed that the primary mechanism of the formation of endometriosis foci is retrograde menstruation, i.e., the passage of menstrual blood through the fallopian tubes into the peritoneal cavity and implantation of exfoliated endometrial cells. However, since this mechanism is also observed in healthy women, other factors must also be involved in the formation of endometriosis foci. Endometriosis is in many women the cause of infertility, chronic pain and the deterioration of the quality of life. It also represents a significant financial burden on health systems. The article presents a review of the literature on endometriosis—a disease affecting women throughout the world.

The diagnostic value of the combination of hemoglobin, CA199, CA125, and HE4 in endometriosis

BACKGROUND

We aimed to analyze the differences in the peripheral blood cells and tumor biomarkers between the patients with endometriosis and healthy people, and establish a more efficient combined diagnostic model.

METHODS

We retrospectively analyzed the differences in the peripheral blood cells and tumor biomarkers between the patients with endometriosis and healthy people. Binary logistic regression analysis was used to establish a combined diagnostic model. We plotted the receiver operator characteristic (ROC) curve to analyze the diagnostic efficiency of different diagnostic indexes.

RESULTS

Compared with patients in the control group, patients in the endometriosis group had significantly lower eosinophil% (p = 0.045), neutrophil (p = 0.001), lymphocyte (p < 0.001), red blood cells (RBCs) (p < 0.001), and hemoglobin (HGB) (p < 0.001), and had significantly higher monocyte% (p = 0.008), monocyte-to-lymphocyte ratio (MLR) (p = 0.001), platelet-to-lymphocyte ratio (PLR) (p < 0.001), carbohydrate antigen (CA)-199 (p < 0.001), CA125 (p < 0.001), human epididymis protein (HE)-4 (p < 0.001), and the risk of ovarian malignancy algorithm (ROMA) (p < 0.001). The combined diagnostic model of HGB, CA199, CA125, and HE4 was established by binary logistic regression analysis. The ROC curve showed that the combined diagnostic model reached a sensitivity of 85.4%, a specificity of 78.83%, and an area under the curve of 0.900, which was significantly higher than that of the individual index in endometriosis diagnosis.

CONCLUSION

The combined diagnostic model of HGB, CA199, CA125, and HE4 may provide a new approach for the early non-invasive diagnosis of endometriosis.

microRNAs as novel diagnostic biomarkers in endometriosis patients: a systematic review and meta-analysis

Objective: To investigate whether miRNAs have a remarkable pooled diagnostic accuracy, sensitivity, and specificity as noninvasive biomarkers to distinguish endometriosis patients from non-endometriosis women.Methods: A comprehensive literature search of PubMed, Embase, and ProQuest was performed through February 21, 2021 to find relevant studies. Two reviewers independently screened each article, and discrepancies were resolved by consensus. Deeks' funnel plot asymmetry test was performed to assess the publication bias of included studies. The STATA software and RevMan 5.4 were used for data analysis and quality assessment, respectively.Results: The overall quality of the studies was moderate to high. In total 87 datasets were assessed miRNAs' performance which results in sensitivity: 0.82, specificity: 0.79, DOR: 18, NPV: 0.80, PPV: 0.78, PLR: 3.97, and NLR: 022. We conducted subgroup analyses, which showed panels of miRNAs (DOR: 54) and serum (DOR: 43) as a target tissue was more reliable to utilize as biomarkers. Deeks' funnel plot showed that there is no publication bias (P-value = 0.25).Conclusions: Panels of miRNAs differentiate endometriosis patients from non-endometriosis women with high sensitivity and specificity; therefore, it has the potential to use as a noninvasive biomarker.

The Inflammatory Feed-Forward Loop Triggered by the Complement Component C3 as a Potential Target in Endometriosis

The complement system is a major component of humoral innate immunity, acting as a first line of defense against microbes via opsonization and lysis of pathogens. However, novel roles of the complement system in inflammatory and immunological processes, including in cancer, are emerging. Endometriosis (EM), a benign disease characterized by ectopic endometrial implants, shows certain unique features of cancer, such as the capacity to invade surrounding tissues, and in severe cases, metastatic properties. A defective immune surveillance against autologous tissue deposited in the peritoneal cavity allows immune escape for endometriotic lesions. There is evidence that the glandular epithelial cells found in endometriotic implants produce and secrete the complement component C3. Here, we show, using immunofluorescence and RT-qPCR, the presence of locally synthesized C3 in the ectopic endometriotic tissue, but not in the eutopic tissue. We generated a murine model of EM via injection of minced uterine tissue from a donor mouse into the peritoneum of recipient mice. The wild type mice showed greater amount of cyst formation in the peritoneum compared to C3 knock-out mice. Peritoneal washings from the wild type mice with EM showed more degranulated mast cells compared to C3 knock-out mice, consistent with higher C3a levels in the peritoneal fluid of EM patients. We provide evidence that C3a participates in an auto-amplifying loop leading to mast cell infiltration and activation, which is pathogenic in EM. Thus, C3 can be considered a marker of EM and its local synthesis can promote the engraftment of the endometriotic cysts.

The Potential of Non-Invasive Biomarkers for Early Diagnosis of Asymptomatic Patients with Endometriosis

Endometriosis is a disease that affects women of reproductive age and has a significantly negative impact on their well-being. The main symptoms are dysmenorrhoea, chronic pelvic pain and infertility. In many patients the diagnostic process is very long and can take up to 8-12 years. Laparoscopy, an invasive method, is still necessary to confirm the diagnosis. Therefore, development of more effective diagnostic markers appears to be of the utmost importance for early diagnosis of endometriosis and provision of appropriate treatment. From a clinical point of view, detection of early-stage endometriosis in asymptomatic patients is an ideal situation since early diagnosis of endometriosis may delay the onset of symptoms as well as prevent progression and complications. In the meantime, Cancer Antigen 125 (CA-125) is still the most frequently studied and used marker. Other glycoproteins, growth factors and immune markers seem to play an important role. However, the search for an ideal endometriosis marker is still underway. Further studies into the pathogenesis of endometriosis will help to identify biomarkers or sets of biomarkers with the potential to improve and speed up the diagnostic process in a non-invasive way.