Prospective Evaluation of a Panel of Plasma Cytokines and Chemokines as Potential Markers of Pelvic Endometriosis in Symptomatic Women

The Known, the Unknown and the Future of the Pathophysiology of Endometriosis

Endometriosis is one of the most common causes of chronic pelvic pain and infertility, affecting 10% of women of reproductive age. A delay of up to 9 years is estimated between the onset of symptoms and the diagnosis of endometriosis. Endometriosis is currently defined as the presence of endometrial epithelial and stromal cells at ectopic sites; however, advances in research on endometriosis have some authors believing that endometriosis should be re-defined as "a fibrotic condition in which endometrial stroma and epithelium can be identified". There are several theories on the etiology of the disease, but the origin of endometriosis remains unclear. This review addresses the role of microRNAs (miRNAs), which are naturally occurring post-transcriptional regulatory molecules, in endometriotic lesion development, the inflammatory environment within the peritoneal cavity, including the role that cytokines play during the development of the disease, and how animal models have helped in our understanding of the pathology of this enigmatic disease.

The Role of Selected Chemokines in the Peritoneal Fluid of Women with Endometriosis—Participation in the Pathogenesis of the Disease

Endometriosis is a disorder characterized by the presence of endometrial tissue outside the uterine cavity, primarily into the peritoneal cavity. It is known as a complex, chronic inflammatory disease and it is strongly associated with immune dysregulation. Various soluble mediators of the immune and inflammatory responses, including chemokines, play an important role in these processes. The aim of the study was to understand the role of the chemokines MCP-1, MCP-2, MCP-3, MCP-4, MIP-1 α, MIP-1β, eotaxin 2, eotaxin 3, ENA-78, and fractalkine in the development of endometriosis through their assessment in the peritoneal fluid of women with endometriosis. The study group included 58 women with endometriosis who were diagnosed during laparoscopy and then confirmed by histopathology. In 15 women from the reference group, laparoscopic examination demonstrated a normal status of the pelvic organs without any evidence of endometriosis nor inflammation in the peritoneal cavity. The peritoneal fluid of women with endometriosis and of women from the reference group were examined. To determine the concentration of the studied chemokines, enzyme immunoassays for Luminex® platforms were used. In the peritoneal fluid of women with endometriosis, a statistically significant increase in the concentration of MIP-1β, eotaxin 2, eotaxin 3, ENA-78, and fractalkine and a decrease in the concentration of MCP-1, MCP-2, MCP-3, MCP-4, and MIP-1α were observed compared to the reference group. The concentration of these cytokines depended on the severity of the disease. Changes in the concentration of the studied chemokines in the peritoneal fluid of women with endometriosis suggest their participation in the pathogenesis of the disease. The differences in chemokines concentration observed in different stages of endometriosis may be associated with the presence of inflammation in the peritoneal cavity at each step of disease development.

Non-invasive diagnosis of endometriosis and moderate-severe endometriosis with serum CA125, endocan, YKL-40, and copeptin quadruple panel

Considering the complex pathogenesis of endometriosis, which is associated with many cellular or molecular processes, such as proliferation, angiogenesis, inflammation, we evaluated the diagnostic value of a quadruple panel of serum markers CA125, endocan, YKL-40 and copeptin, for the prediction of endometriosis and moderate - severe endometriosis. Seventy women with endometriosis and 70 women without endometriosis were evaluated. Serum CA125, endocan, copeptin and YKL-40 levels were significantly increased in women with endometriosis compared to the women without endometriosis and in the minimal - mild endometriosis group compared to the no-endometriosis group. YKL-40, endocan and copeptin levels were significantly increased in the moderate - severe endometriosis group compared to the mild -moderate endometriosis group but the difference in CA125 levels remained non-significant. The quadruple panel score had an AUC of 0.954, a sensitivity of 96.5% and specificity of 84.6% for prediction of moderate - severe endometriosis. Zero or one positive marker had a sensitivity of 91.4% and specificity of 88.57% to rule out endometriosis. In conclusion, a quadruple panel of serum markers-CA125, endocan, YKL-40, and copeptin may be beneficial for the diagnosis of endometriosis and especially moderate - severe endometriosis. Further studies are needed to prove the efficacy of this panel.Impact statementWhat is already known on this subject? Many serum markers including CA125 have been investigated so far and suggested to be associated with endometriosis. However, none of these markers is sensitive and specific enough to diagnose endometriosis.What do the results of this study add? A quadruple panel score (CA125, endocan, YKL-4 and copeptin) had an AUC of 0.954, a sensitivity of 96.5% and specificity of 84.6% for prediction of moderate - severe endometriosis.What are the implications of these findings for clinical practice and/or further research? A high score may be beneficial to warn the surgeon about the risk of moderate to severe endometriosis if the patient will be operated anyway. A negative test of the quadruple panel may show high odds that there is no endometriosis which may prevent unnecessary surgery.

Peritoneal fluid biomarkers in patients with endometriosis: a cross-sectional study

OBJECTIVES

Elevated concentrations of numerous molecules have been reported in the peritoneal cavity of women with endometriosis. Until now, no factor proved sufficiently specific to endometriosis. We aimed to investigate several biomarkers in endometriosis and report their association with the menstrual cycle in a large sample size study.

METHODS

Patients of reproductive age undergoing laparoscopic procedures for benign pathology in the Department of Obstetrics and Gynaecology, University of Bern between 2007 and 2018 were included. Exclusion criteria were the use of hormonal treatment in the three months prior to surgery, patients suffering from other inflammatory diseases, pregnancy, malignancy and surgery performed in an emergency. The concentrations of 13 different biomarkers in the peritoneal fluid (PF) were compared between patients with and without endometriosis both in the proliferative and the secretory cycle phase.

RESULTS

Out of 1,256 patients in the database, 521 met the inclusion and exclusion criteria. Glycodelin (PP14) and Midkine concentrations were significantly higher in patients with endometriosis compared to controls irrespective of the cycle phase in which the PF was collected. Interleukin-8 (IL-8), regulated on activation normal T cell expressed and secreted (RANTES) and osteoprotegerin (OPG) concentrations were higher in patients with endometriosis only in the proliferative cycle phase. Monocyte chemoattractant protein 1, CCL2 (MCP-1) and Defensin concentrations were higher in patients with endometriosis only in the secretory cycle phase.

CONCLUSIONS

Certain pathophysiological processes may take place only in the one cycle phase leading to a temporary increase of specific PF biomarkers. Correlation with clinical outcomes is mandatory to establish their potential as prognostic or therapeutic tools in endometriosis.

Multiplex analysis of 40 cytokines do not allow separation between endometriosis patients and controls

Endometriosis is a common gynaecological condition characterized by severe pelvic pain and/or infertility. The combination of nonspecific symptoms and invasive laparoscopic diagnostics have prompted researchers to evaluate potential biomarkers that would enable a non-invasive diagnosis of endometriosis. Endometriosis is an inflammatory disease thus different cytokines represent potential diagnostic biomarkers. As panels of biomarkers are expected to enable better separation between patients and controls we evaluated 40 different cytokines in plasma samples of 210 patients (116 patients with endometriosis; 94 controls) from two medical centres (Slovenian, Austrian). Results of the univariate statistical analysis showed no differences in concentrations of the measured cytokines between patients and controls, confirmed by principal component analysis showing no clear separation amongst these two groups. In order to validate the hypothesis of a more profound (non-linear) differentiating dependency between features, machine learning methods were used. We trained four common machine learning algorithms (decision tree, linear model, k-nearest neighbour, random forest) on data from plasma levels of proteins and patients’ clinical data. The constructed models, however, did not separate patients with endometriosis from the controls with sufficient sensitivity and specificity. This study thus indicates that plasma levels of the selected cytokines have limited potential for diagnosis of endometriosis.

Anti-inflammatory cytokines in endometriosis

Although the pathogenesis of endometriosis is not fully understood, it is often considered to be an inflammatory disease. An increasing number of studies suggest that differential expression of anti-inflammatory cytokines (e.g., interleukin-4 and -10, and transforming growth factor-β1) occurs in women with endometriosis, including in serum, peritoneal fluid and ectopic lesions. These anti-inflammatory cytokines also have indispensable roles in the progression of endometriosis, including by promoting survival, growth, invasion, differentiation, angiogenesis, and immune escape of the endometriotic lesions. In this review, we provide an overview of the expression, origin, function and regulation of anti-inflammatory cytokines in endometriosis, with brief discussion and perspectives on their future clinical implications in the diagnosis and therapy of the disease.

Noninvasive diagnosis of endometriosis: Review of current peripheral blood and endometrial biomarkers

A noninvasive biomarker-based test could help shorten the diagnostic delay for endometriosis. The most investigated biomarker sources are peripheral blood and endometrium. Discovery of endometriosis biomarkers is often hypothesis-driven, i.e. when one or a few biomarkers are investigated based on their role in the disease pathogenesis. Alternatively, a hypothesis-generating approach has been followed using the "omics" technologies. A variety of biomarkers for endometriosis have been investigated, but no biomarker has been validated for clinical use. Many challenges lie ahead in the endometriosis biomarker field. In the future, harmonized collection and reporting methods should allow large-scale international collaboration for highly powered studies.

Eotaxin levels in patients with primary dysmenorrhea

Purpose

Primary dysmenorrhea (PD) is a common cause of pelvic pain that can cause limitations in daily activities. Treatment options sometimes result in failure, suggesting that different mechanisms may be effective in etiopathogenesis. Eosinophils are cells that are present in endometrium only in the perimenstrual period. The aim of this study was to evaluate the levels of eotaxin, a potent eosinophilic chemoattractant, in patients with PD.

Patients and methods

Thirty patients with PD and thirty healthy women were included in the study. Venous blood sample of 10 mL was collected from each participant. Blood samples were taken in the first 2 days of the menstrual cycle at any period of the day. Serum eotaxin levels were determined by enzyme-linked immunofluorescence assay.

Results

There were no statistically significant differences between the demographic properties of groups in terms of age and body mass index. Eotaxin levels were significantly different in patients with PD than the control subjects (p=0.012).

Conclusion

Detection of different levels of eotaxin in patients with PD may be a new and important step in determining the factors contributing to the pathogenesis of dysmenorrhea.

Plasma urocortin-1 as a preoperative marker of endometriosis in symptomatic women

Accurate noninvasive diagnostic tests for endometriosis are still missing. This study evaluated the predictive value of the neuropeptide urocortin 1 (Ucn1) to detect pelvic endometriosis in symptomatic women. We enrolled prospectively 97 consecutive women submitted to gynecologic laparoscopy for chronic or acute pelvic pain, infertility or adnexal mass. Preoperative blood samples were assayed for Ucn1 using enzyme immunoassay. Patients with endometriosis had higher plasma Ucn1 levels compared to patients with no lesions (median 59 vs. 34 pg/ml, p < .01, Dunn's test). Elevated plasma Ucn1 levels were found among all endometriosis phenotypes (superficial peritoneal lesions, ovarian endometrioma, and deep infiltrating endometriosis, p < .05 vs. no lesions). Receiver operating characteristics curve analysis identified plasma Ucn1 > 46 pg/mL as the best cutoff point to detect endometriosis vs. no lesions, with 76% sensitivity and 88% specificity (area under the curve [AUC] 0.827, 95% confidence interval [CI] 0.695 - 0.959), but no cutoff could accurately distinguish endometriosis from other pathological conditions (AUC 0.593 [95% CI 0.474 - 0.711]). In women with chronic pelvic pain, infertility, or both symptoms, the probability of endometriosis (positive predictive value) increased consistently with the increase of plasma Ucn1 levels. The present findings suggest that high plasma Ucn1 levels increase the likelihood of endometriosis in symptomatic women.

Should we consider integrated approach for endometriosis-associated infertility as gold standard management? Rationale and results from a large cohort analysis

PURPOSE

To evaluate reproductive and maternal-fetal outcomes after integrated approach for endometriosis-associated infertility (EAI).

METHODS

We retrospectively analyzed reproductive and maternal-fetal outcomes of 277 women affected by EAI, subdividing patients in two groups: in the first one (surgery group), we included all women who underwent laparoscopic surgery for EAI; in the second one (integrated group), we included women who failed to conceive spontaneously after surgery within 6-12 months and underwent in vitro fertilization and embryo transfer (IVF). We evaluated delivery rate (DR), maternal and neonatal outcomes of the first pregnancies, and, finally, the type (spontaneous or IVF) of subsequent pregnancies.

RESULTS

We did not find significant difference regarding DR between surgery and integrated groups. We found significantly lower birth weight (p < 0.001) and gestational age at delivery (p < 0.001) in integrated group respect to surgery group; conversely, we found higher rate of preterm birth (p < 0.001), small for gestational age (p = 0.003), and admission to the neonatal intensive care unit (p < 0.001) respect to surgery group. Finally, 92 women became pregnant for the second time: 8% were spontaneous and 20% were IVF pregnancies.

CONCLUSIONS

We suggest the integrated approach as gold standard treatment for carefully selected patients (young, good ovarian reserve, partner with normal semen parameters) affected by EAI. As consequence, IVF should be reserved as the secondary treatment for women who fail to conceive spontaneously after surgery within 6-12 months, since it is able to increase DR significantly.

Tumor Necrosis Factor and its Soluble Receptors as Potential Diagnostic Markers of Endometriosis

Introduction

Tumor necrosis factor (TNF) is a proinflammatory and angiogenic factor produced by activated macrophages. TNF acts through the cell membrane receptors TNFR1 and TNFR2, whose soluble forms play an important role in regulating TNF activity through competition with its receptors. The aim of this study was to evaluate whether TNF and/or its soluble receptors are useful to detect endometriosis in women undergoing laparoscopy for gynecological complains.

Methods

This was a prospective, controlled, cross-sectional study including 75 consecutive women scheduled for gynecological laparoscopy due to chronic pelvic pain, infertility, or a pelvic image suggestive of endometrioma. Plasma TNF and soluble TNF receptors (sTNFR1 and sTNFR2) were measured by flow cytometry with the Cytometric Bead Array Human TH1/TH2 Kit (BD Biosciences).

Results

Women ultimately proven to have endometriosis had lower preoperative plasma levels of sTNFR1 (median 81 pg/mL vs. 121 pg/mL, p<0.05), resulting in higher TNF/sTNFR1 ratios compared to those without endometriosis (0.055 vs. 0.033, p<0.05). Using the cut-off <108 pg/mL for plasma sTNFR1 to detect endometriosis in this setting, the sensitivity was 51.6% (95% confidence interval [CI], 35%-68%), the specificity was 75.0% (95% CI, 61%-85%) and the positive likelihood ratio was 2.1 (95% CI, 1.1-3.8). The area under the ROC curve was 0.647 (SE = 0.065; 95% CI, 0.519-0.774; p = 0.031).

Conclusions

Plasma sTNFR1 levels are lower in symptomatic women with confirmed endometriosis compared to symptomatic women without endometriosis. The lower plasma sTNFR1 levels may increase the bioavailability of TNF, thereby contributing to the systemic low grade inflammation associated with endometriosis.