Selected cytokines and glycodelin A levels in serum and peritoneal fluid in girls with endometriosis

Endometriosis and mental health: a population-based cohort study

BACKGROUND

Endometriosis is a chronic gynecologic disorder that leads to considerable pain and a reduced quality of life. Although its physiological manifestations have been explored, its impact on mental health is less well defined. Existing studies of endometriosis and mental health were conducted within diverse healthcare landscapes with varying access to care and with a primary focus on surgically diagnosed endometriosis. A single-payer healthcare system offers a unique environment to investigate this association with fewer barriers to access care while considering the mode of endometriosis diagnosis.

OBJECTIVE

Our objective was to assess the association between endometriosis and the risk for mental health conditions and to evaluate differences between patients diagnosed medically and those diagnosed surgically.

STUDY DESIGN

A matched, population-based retrospective cohort study was conducted in Ontario and included patients aged 18 to 50 years with a first-time endometriosis diagnosis between January 1, 2010, and July 1, 2020. Endometriosis exposure was determined through either medical or surgical diagnostic criteria. A medical diagnosis was defined by the use of the corresponding International Classification of Disease diagnostic codes from outpatient and in-hospital visits, whereas a surgical diagnosis was identified through inpatient or same-day surgeries. Individuals with endometriosis were matched 1:2 on age, sex, and geography to unexposed individuals without a history of endometriosis. The primary outcome was the first occurrence of any mental health condition after an endometriosis diagnosis. Individuals with a mental health diagnosis in the 2 years before study entry were excluded. Cox regression models were used to generate hazard ratios with adjustment for hysterectomy, salpingo-oophorectomy, infertility, pregnancy history, qualifying surgery for study inclusion, immigration status, history of asthma, abnormal uterine bleeding, diabetes, fibroids, hypertension, irritable bowel disorder, migraines, and nulliparity.

RESULTS

A total of 107,832 individuals were included, 35,944 with a diagnosis of endometriosis (29.5% medically diagnosed, 60.5% surgically diagnosed, and 10.0% medically diagnosed with surgical confirmation) and 71,888 unexposed individuals. Over the study period, the incidence rate was 105.3 mental health events per 1000 person-years in the endometriosis group and 66.5 mental health events per 1000 person-year among unexposed individuals. Relative to the unexposed individuals, the adjusted hazard ratio for a mental health diagnosis was 1.28 (95% confidence interval, 1.24-1.33) among patients with medically diagnosed endometriosis, 1.33 (95% confidence interval, 1.16-1.52) among surgically diagnosed patients, and 1.36 (95% confidence interval, 1.2-1.6) among those diagnosed medically with subsequent surgical confirmation. The risk for receiving a mental health diagnosis was highest in the first year after an endometriosis diagnosis and declined in subsequent years. The cumulative incidence of a severe mental health condition requiring hospital visits was 7.0% among patients with endometriosis and 4.6% among unexposed individuals (hazard ratio, 1.56; 95% confidence interval, 1.53-1.59).

CONCLUSION

Endometriosis, regardless of mode of diagnosis, is associated with a marginally increased risk for mental health conditions. The elevated risk, particularly evident in the years immediately following the diagnosis, underscores the need for proactive mental health screening among those newly diagnosed with endometriosis. Future research should investigate the potential benefits of mental health interventions for people with endometriosis with the aim of enhancing their overall quality of life.

An integrated multi-tissue approach for endometriosis candidate biomarkers: a systematic review

Biomarker identification could help in deciphering endometriosis pathophysiology in addition to their use in the development of non invasive diagnostic and prognostic approaches, that are essential to greatly improve patient care. Despite extensive efforts, no single potential biomarker or combination has been clinically validated for endometriosis.Many studies have investigated endometriosis-associated biological markers in specific tissues, but an integrative approach across tissues is lacking. The aim of this review is to propose a comprehensive overview of identified biomarkers based on tissue or biological compartment, while taking into account endometriosis phenotypes (superficial, ovarian or deep, or rASRM stages), menstrual cycle phases, treatments and symptoms.We searched PubMed and Embase databases for articles matching the following criteria: 'endometriosis' present in the title and the associated term 'biomarkers' found as Medical Subject Headings (MeSH) terms or in all fields. We restricted to publications in English and on human populations. Relevant articles published between 01 January 2005 (when endometriosis phenotypes start to be described in papers) and 01 September 2022 were critically analysed and discussed.Four hundred forty seven articles on endometriosis biomarkers that included a control group without endometriosis and provided specific information on endometriosis phenotypes are included in this review. Presence of information or adjustment controlling for menstrual cycle phase, symptoms and treatments is highlighted, and the results are further summarized by biological compartment. The 9 biological compartments studied for endometriosis biomarker research are in order of frequency: peripheral blood, eutopic endometrium, peritoneal fluid, ovaries, urine, menstrual blood, saliva, feces and cervical mucus. Adjustments of results on disease phenotypes, cycle phases, treatments and symptoms are present in 70%, 29%, 3% and 6% of selected articles, respectively. A total of 1107 biomarkers were identified in these biological compartments. Of these, 74 were found in several biological compartments by at least two independent research teams and only 4 (TNF-a, MMP-9, TIMP-1 and miR-451) are detected in at least 3 tissues with cohorts of 30 women or more.Integrative analysis is a crucial step to highlight potential pitfalls behind the lack of success in the search for clinically relevant endometriosis biomarkers, and to illuminate the physiopathology of this disease.

Circulating proteomic profiles associated with endometriosis in adolescents and young adults

STUDY QUESTION

What are the systemic molecular profiles of endometriosis diagnosed in adolescents and young adults?

SUMMARY ANSWER

Significant enrichment and increased activation of proteins related to angiogenesis and cell migration pathways were observed in endometriosis cases compared to controls (P-value < 2.4 × 10-8).

WHAT IS KNOWN ALREADY

Little is known about the pathophysiology of adolescent endometriosis despite the fact that over 50% of adults with endometriosis report onset of severe pelvic pain during adolescence.

STUDY DESIGN, SIZE, DURATION

A cross-sectional analysis using data on 142 laparoscopically confirmed endometriosis cases and 74 controls from the observational longitudinal cohort of Women's Health Study: From Adolescence to Adulthood (A2A).

PARTICIPANTS/MATERIALS, SETTING, METHODS

We measured 1305 plasma protein levels using the validated, multiplex aptamer-based proteomics discovery platform, SOMAscan. We calculated odds ratios and 95% CIs using logistic regression adjusting for age, BMI, fasting status and hormone use at blood draw for differentially expressed proteins (P < 0.05). Ingenuity Pathway Analysis and STRING analysis were performed to identify biological pathways and protein interactions. We also examined proteins and pathways associated with superficial peritoneal lesion colors (i.e. red, vascularized, white, blue/black, brown).

MAIN RESULTS AND THE ROLE OF CHANCE

Average age at blood draw was 18 years for endometriosis cases and 22 years for controls. We identified 63 proteins associated with endometriosis with type-I error set at 0.05, and absolute fold change >1.2, revealing significant enrichment of dysregulated proteins in biological pathways associated with endometriosis. Increased activation of pathways related to angiogenesis and cell migration was observed in plasma from endometriosis cases compared to controls (P-value < 2.4 × 10-8). Furthermore, when we examined proteins and pathways associated with lesion colors, vascularized lesions were associated with upregulation of pathways related to immune cell migration/activation and inflammation, whereas white, blue/black and brown lesions were associated with downregulation of these pathways.

LIMITATIONS, REASONS FOR CAUTION

Validation of our results in independent datasets and mechanistic studies are warranted to further our understanding of the pathophysiological characteristics of this common but understudied patient population.

WIDER IMPLICATIONS OF THE FINDINGS

To our knowledge, this was the first study to comprehensively examine circulating proteins in predominantly adolescents and young adult women with and without endometriosis. Results from this study provide novel biological insight that will build toward further research to elucidate endometriosis pathophysiology during the earlier course of the disease trajectory.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the Department of Defense (W81XWH1910318) and the 2017 Boston Center for Endometriosis Trainee Award. Financial support for establishment of and data collection within the A2A cohort were provided by the J. Willard and Alice S. Marriott Foundation. N.S., A.F.V., S.A.M., K.L.T. have received funding from Marriott Family Foundation. S.A.M. and K.L.T. are supported by NICHD (R01 HD94842). S.A.M. serves as an advisory board member for AbbVie and Roche; neither are related to this study. The authors report no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

Novel diagnostic options for endometriosis - Based on the glycome and microbiome

Background

Endometriosis is a chronic gynaecological disease whose aetiology is still unknown. Despite its prevalence among women of reproductive age, the pathology of the disease has not yet been elucidated and only symptomatic treatment is available. Endometriosis has high latency and diagnostic methods are both limited and invasive.

Aim of review

The aim of this review is to summarise minimally invasive or non-invasive diagnostic methods for endometriosis and their diagnostic efficiencies. Furthermore, we discuss the identification and diagnostic potential of novel disease biomarkers of microbial or glycan origin.

Key scientific concepts of review

Great efforts have been made to develop minimally invasive or non-invasive diagnostic methods in endometriosis. The problem with most potential biomarker candidates is that they have high accuracy only in cases of severe disease. Therefore, it is necessary to examine other potential biomarkers more closely. Associations between gastrointestinal and genital tract microbial health and endometriosis have been identified. For instance, irritable bowel syndrome is more common in women with endometriosis, and hormonal imbalance has a negative impact on the microbiome of both the genital tract and the gastrointestinal system. Further interrogation of these associations may have potential diagnostic significance and may identify novel therapeutic avenues. Glycomics may also be a potent source of biomarkers of endometriosis, with a number of glyco-biomarkers already approved by the FDA. Endometriosis-associated microbial and glycomic profiles may represent viable targets for development of innovative diagnostics in this debilitating disease.

The Search for Biomarkers in Endometriosis: a Long and Windy Road

Endometriosis is a complex and chronic estrogen-dependent disease, affecting a significant proportion of women of reproductive age. Despite the long interest and extensive research, the pathogenesis of the disease is still debated. Although available non-invasive diagnostic methods have adequate accuracy, an invasive approach by laparoscopy is often necessary to obtain histological confirmation. In this scenario, the search for an accurate, reliable, cost-effective, clinically applicable non-invasive biomarker plays a crucial role in a potentially early diagnosis and, in this way, shape the future management of the disease. Considering these elements, the current review aims to summarize the most significant and novel results about biomarkers for the diagnosis and follow-up of women affected by endometriosis.

Point-of-care detection of cytokines in cytokine storm management and beyond: Significance and challenges

Cytokines are signaling molecules between cells in immune system. Cytokine storm, due to the sudden acute increase in levels of pro‐inflammatory circulating cytokines, can result in disease severity and major‐organ damage. Thus, there is urgent need to develop rapid, sensitive, and specific methods for monitoring of cytokines in biology and medicine. Undoubtedly, point‐of‐care testing (POCT) will provide clinical significance in disease early diagnosis, management, and prevention. This review aims to summarize and discuss the latest technologies for detection of cytokines with a focus on POCT. The overview of diseases resulting from imbalanced cytokine levels, such as COVID‐19, sepsis and other cytokine release syndromes are presented. The clinical cut‐off levels of cytokine as biomarkers for different diseases are summarized. The challenges and perspectives on the development of cytokine POCT devices are also proposed and discussed. Cytokine POCT devices are expected to be the ongoing spotlight of disease management and prevention during COVID‐19 pandemic and also the post COVID‐19 pandemic era.

Endometriosis: New Perspective for the Diagnosis of Certain Cytokines in Women and Adolescent Girls, as Well as the Progression of Disease Outgrowth: A Systematic Review

Endometriosis is a common chronic gynecological disorder that undoubtedly impacts on quality of life, and is one of the more complex and mysterious illnesses of our century, which is associated with the improper growth of endometrial tissue outside of the uterine cavity. This pathologically implanted tissue can be found most frequently in the minor pelvis, but also in the peritoneal cavity, and can affect many organs, leading to chronic pelvic pain syndrome, infertility, and dysmenorrhea. Endometrial tissue is a particularly dynamic tissue that has a direct impact on the progression of the disease, with altered immunity, as well as cytokine storms within the metaplastic endometriotic site, as possible key factors. Currently, diagnosis of this mysterious chronic illness relies on performing a laparoscopic procedure with tissue sampling. One of the most troublesome outcomes of this unintended progression is that we lack any specific, sensitive, non-invasive diagnostic tools. Currently, the vast majority of regime stewardship options rely on anti-contraceptive drugs, or other remedies that suppress the release of estrogen through the gonads-although in most clinical trials, endometriosis is a chronic progressive disorder that depends mostly on the high concentration of estrogen. Moreover, many specific trials have demonstrated that the eutopic endometrial cells in individuals with endometriosis remain much more resistant to the immunological annihilation process caused by certain elements of the immune system. Nevertheless, eutopic endometrial cells have the potential to similarly escalate the expression of aromatase receptors on the surface of the pathological cells, which in the final cascade cause an increase in the concentration of estrogen, as well as other inflammatory proteins that contribute to pathological outgrowth. Data reveal occurrence among first-degree relatives, suggesting that the specific cascade could be related to inherited as well as epigenetic (acquired) mechanisms. In women with the disease, confirmed by laparoscopic procedures, diagnosis of endometriosis can be established also via detection by gene polymorphism in the genes which are responsible for responsible for the detoxification phase of estrogen receptors and other immunomodulator components. A recent publication aims to reveal a new prospect for the non-invasive diagnosis, detection, and estimation of certain biomarkers for much more specific investigation of the disease's progression.

Platelets and Regulatory T Cells May Induce a Type 2 Immunity That Is Conducive to the Progression and Fibrogenesis of Endometriosis

Endometriosis is a hormonal disease, as well as a chronic inflammatory disease. While various immune cells are documented to be involved in endometriosis, there is a wanton lack of a bigger picture on how these cells are coordinated to work concertedly. Since endometriotic lesions experience cyclical bleeding, they are fundamentally wounds that undergo repeated tissue injury and repair (ReTIAR). In this study, we attempted to characterize the role of platelets and regulatory T cells (Tregs) in modulating the lesional immune microenvironment and its subsequent effects on lesional progression and fibrogenesis. Through two mouse experiments, we show that, by disrupting predominantly a type 2 immune response in lesional microenvironment, both platelets and Tregs depletion decelerated lesional progression and fibrogenesis, likely through the suppression of the TGF-β1/Smad3 and PDGFR-β/PI3K/Akt signaling pathways. In particular, platelet depletion resulted in significantly reduced lesional expression of thymic stromal lymphopoietin (TSLP), leading to reduced aggregation of macrophages and alternatively activated (M2) macrophages, and of Tregs, T helper 2 (Th2) and Th17 cells but increased aggregation of Th1 cells, in lesions, which, in turn, yields retarded fibrogenesis. Similarly, Tregs depletion resulted in suppression of platelet aggregation, and reduced aggregation of M2 macrophages, Th2 and Th17 cells but increased aggregation of Th1 cells, in lesions. Thus, both platelet and Tregs depletion decelerated lesional progression and fibrogenesis by disrupting predominantly a type 2 immunity in lesional microenvironment. Taken together, this suggests that both platelets and Tregs may induce a type 2 immunity in lesional microenvironment that is conducive to lesional progression and fibrogenesis.

Interleukin in endometriosis-associated infertility-pelvic pain: systematic review and meta-analysis

The objective is to study the significance of altered interleukin levels in endometriosis-related infertility or pelvic pain. The present systematic review and meta-analysis includes a discussion on the roles of interleukin in the physiopathology of endometriosis-associated infertility and/or pelvic pain. We included all studies in which interleukins in peritoneal fluid, follicular fluid or serum from patients were measured and that correlated the findings with either peritoneal or deep endometriosis-associated infertility or pelvic pain. For the meta-analysis, we selected studies on the following cytokines: interleukin-1 (IL-1), interleukin-6 (IL-6) and interleukin-8 (IL-8). Endometriosis is a chronic inflammatory disease. Inflammatory processes clearly participate in the etiology of endometriosis. Cytokines are mediators of inflammation, and increase in their concentration in plasma or other body fluids signals the presence and extent of tissue lesions. A number of studies have reported on the association between higher cytokine levels and progression or maintenance of endometriosis and coexisting infertility or pelvic pain. The results of the analyses support that an association exists between elevated serum IL-6 and/or IL-8 concentrations and the occurrence of endometriosis-associated infertility. Such association was not found for endometriosis-associated pain. In spite of accumulated evidence on the association of pro-inflammatory cytokines and endometriosis, it still is not clear if and how these mediators participate in the physiopathology of endometriosis-associated infertility or pelvic pain, in part due to poor quality of the evidence established in the vast majority of interleukins and challenges in endometriosis research reproducibility. In summary, the results of the analyses support that an association exists between elevated serum IL-6 and/or IL-8 concentrations and the occurrence of endometriosis-associated infertility.

Peripheral Blood Leukocyte Telomere Length and Endometriosis

Endometriosis is a common gynecologic disease defined by the presence of endometrial-like tissue outside the uterine cavity. While its etiology is largely unknown, accumulating evidence suggests that inflammation plays a major role. Our objective was to investigate the association between peripheral blood leukocyte telomere length (LTL) and endometriosis using data from two large population-based studies, the New England Case-Control Study (NEC; n = 877) and the National Health and Nutrition Examination Survey (NHANES; n = 2268). NEC control participants were identified through a combination of random digit dialing, drivers' license lists, and town resident lists. In NHANES, selection algorithms were used to identify a nationally representative sample. Blood samples and demographic, reproductive, and health-related information were available from both data sources. Endometriosis was defined as self-reported of physician-diagnosed endometriosis. LTL was measured using quantitative polymerase chain reaction. Multivariable logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals (CI) for the association between LTL and endometriosis. Shorter LTL was associated with greater odds of history of endometriosis. In NEC, women with the shortest LTL tertile compared with the longest had a 2.5-fold greater odds of endometriosis (OR_T3/T1 = 2.56, 95% CI = 1.16-5.63; p value, test for linear trend = 0.02). The association was stronger among women who usually experienced moderate or severe menstrual pain (OR _T3/T1 = 3.50, 95% CI = 1.12-10.97). In NHANES, the data suggested a similar but attenuated association (OR_T3/T1 = 1.29, 95% CI = 0.85-1.96). The observed associations in NEC suggest that shorter LTL may be associated with greater odds of endometriosis. A better understanding of how LTL influences endometriosis risk could elucidate novel disease pathophysiology.

Pathophysiological Basis of Endometriosis-Linked Stress Associated with Pain and Infertility: A Conceptual Review

Women with endometriosis are often under stress due to the associated pain, infertility, inflammation-related and other comorbidities including cancer. Additionally, these women are also under stress due to taboos, myths, inter-personal troubles surrounding infertility and pain of the disease as well as due to frequent incidences of missed diagnosis and treatment recurrence. Often these women suffer from frustration and loss of valuable time in the prime phase of life. All these complexities integral to endometriosis posit a hyperstructure of integrative stress physiology with overt differentials in effective allostatic state in women with disease compared with disease-free women. In the present review, we aim to critically examine various aspects of pathophysiological basis of stress surrounding endometriosis with special emphasis on pain and subfertility that are known to affect the overall health and quality of life of women with the disease and promising pathophysiological basis for its effective management.

Serum miR-17, IL-4, and IL-6 levels for diagnosis of endometriosis

Clinical studies have exhibited microRNAs or cytokines could be used as new biomarkers in the diagnosis of endometriosis, respectively. The purpose of this study was to investigate the role of serum miR-17, IL-4, and IL-6 as early diagnostic markers of endometriosis. One hundred forty patients aged 22 to 45 years were recruited, 80 patients with pathologically confirmed endometriosis were assigned to endometriosis group whereas the remaining 60 patients were in the control group. The blood samples were collected immediately before laparoscopy and analyzed using real-time quantitative PCR analysis. In patients with endometriosis, the level of miR-23b decreased significantly, the levels of IL-4 and IL-6 increased remarkably compared with that in patients without endometriosis. Correlation analysis revealed miR-17 levels were negatively correlated with IL-4 (r = -0.974, P < .05) and IL-6 (r = -0.944, P < .05). The ROC curve manifested joint of miR-17 and selected cytokines could improve the diagnostic power with an AUC of 0.84 (95% CI: 0.75-0.96). In short, the present study characterizes the role of miR-17, IL-4, and IL-6 in the pathogenesis of endometriosis, suggesting the feasibility of using miR-17 and selected cytokines as a noninvasive diagnostic test for the detection of endometriosis.

The role of IL‑16 gene polymorphisms in endometriosis

Endometriosis is one of the most common gynecological diseases affecting up to 10% of the female population of childbearing age and a major cause of pain and infertility. It is influenced by multiple genetic, epigenetic and environmental factors. Interleukin-16 (IL-16) is a proinflammatory cytokine playing a pivotal role in many inflammatory and autoimmune diseases as well as in the pathogenesis of endometriosis. The aim of the present study was to evaluate the association of two IL-16 gene single nucleotide polymorphisms (SNPs), rs4072111 and rs11556218, with the risk of endometriosis in women from Greece as well as to gain insight about the structural consequences of these two exonic SNPs regarding development of the disease. A total of 159 women with endometriosis (stages I–IV) hospitalized for endometriosis, diagnosed by laparoscopic intervention and histologically confirmed, and 146 normal controls were recruited and genotyped. Subjects were genotyped using a polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) strategy. A significant association was detected regarding the GG and GT genotype as well as 'G' allele of rs11556218 in patients with endometriosis. The rs4072111 SNP of the IL-16 gene was not found to be associated with an increased susceptibility to endometriosis either for all patients (stages I–IV) or for stage III and IV of the disease only. Our results demonstrated that rs11556218 is associated with endometriosis in Greek women, probably by resulting in the aberrant expression of IL-16, as suggested by the bioinformatics analysis conducted on the SNP-derived protein sequences, which indicated a possible association between mutation and functional modification of Pro-IL-16.

Association of interleukin-16 polymorphisms with disease progression and susceptibility in endometriosis

Interleukin-16 (IL-16) is a multifunctional pro-inflammatory cytokine that was previously found in association with complex disorders, and it is now cleared that this cytokine plays a critical role in regulation of cellular functions such as homoeostasis. Due to the complexity of endometriosis and its resemblance to cancer, we designed present case-control study to determine the effects of genetic polymorphisms of the human IL-16 gene on Iranian women's susceptibility to endometriosis. A total of 126 patients with endometriosis (stages I-IV) and 144 healthy women as control group were recruited to the study. We genotyped four single nucleotide polymorphisms of IL-16 gene (rs11556218 T>G, rs4778889 T>C, rs4072111 C>T and rs1131445 C>T). Genotyping was performed using PCR and restriction fragment length polymorphism. Our results showed that genotype distribution in two exonic polymorphisms including rs11556218 and rs4072111 was significantly different between Endometriosis patients and healthy individuals (P < 0.05). We have also found an association between rs4072111 and rs1131445 with progression to the severe stages (III-IV) of endometriosis (P < 0.05). Finally, we may conclude that IL-16 gene polymorphisms are highly associated with increased risk of endometriosis and could be considered as a susceptibility factor for endometriosis.

Altered levels of acylcarnitines, phosphatidylcholines, and sphingomyelins in peritoneal fluid from ovarian endometriosis patients

Endometriosis is a complex, polygenic, and estrogen-dependent disease that affects 6% to 10% of women of reproductive age, and 30% to 50% of women with infertility and/or pelvic pain. Surgical diagnosis of endometriosis is still the gold standard, as there are currently no diagnostic biomarkers available. Due to the invasive diagnostics, it can take up to 11 years before affected women are diagnosed and receive the appropriate treatment. We performed a targeted metabolomics study to search for potential semi-invasive biomarkers in peritoneal fluid from endometriosis patients. Our case-control study comprised 29 ovarian endometriosis patients and 36 healthy control women. The 148 metabolites included acylcarnitines, glycerophospholipids, and sphingolipids, which were quantified by electrospray ionization tandem mass spectrometry. The strength of association between the metabolites and the metabolite ratios and disease was assessed using crude and adjusted odds ratios. The best combination of biomarkers was then selected by performing step-wise logistic regression. Our analysis reveals significantly decreased concentrations of 10 metabolites, of carnitine and acylcarnitines (C0, C8:1, C6C4:1 DC, C10:1), phosphatidylcholines (PC aa C38:3, PC aa C38:4, PC aa C40:4, PC aa C40:5), and sphingomyelins (SM C16:1, SM C18:1), and 125 significantly altered metabolite ratios in patients versus control women. The best model includes two ratios: a carnitine to a phosphatidylcholine (C0/PC ae C36:0); and between two phosphatidylcholines (PC aa C30:0/PC ae C32:2). When adjusted for age, this provides sensitivity of 82.8% and specificity of 94.4%, with AUC of 0.944. Our study supports the importance of carnitine, phosphatidylcholine, and sphingomyelin metabolites in the pathophysiology of endometriosis, and confirms the potential for the combination of individual metabolite ratios to provide biomarkers for semi-invasive diagnostics.

Blood biomarkers for the non-invasive diagnosis of endometriosis

BACKGROUND

About 10% of reproductive-aged women suffer from endometriosis, a costly chronic disease causing pelvic pain and subfertility. Laparoscopy is the gold standard diagnostic test for endometriosis, but is expensive and carries surgical risks. Currently, there are no non-invasive or minimally invasive tests available in clinical practice to accurately diagnose endometriosis. Although other reviews have assessed the ability of blood tests to diagnose endometriosis, this is the first review to use Cochrane methods, providing an update on the rapidly expanding literature in this field.

OBJECTIVES

To evaluate blood biomarkers as replacement tests for diagnostic surgery and as triage tests to inform decisions on surgery for endometriosis. Specific objectives include:1. To provide summary estimates of the diagnostic accuracy of blood biomarkers for the diagnosis of peritoneal, ovarian and deep infiltrating pelvic endometriosis, compared to surgical diagnosis as a reference standard.2. To assess the diagnostic utility of biomarkers that could differentiate ovarian endometrioma from other ovarian masses.

SEARCH METHODS

We did not restrict the searches to particular study designs, language or publication dates. We searched CENTRAL to July 2015, MEDLINE and EMBASE to May 2015, as well as these databases to 20 April 2015: CINAHL, PsycINFO, Web of Science, LILACS, OAIster, TRIP, ClinicalTrials.gov, DARE and PubMed.

SELECTION CRITERIA

We considered published, peer-reviewed, randomised controlled or cross-sectional studies of any size, including prospectively collected samples from any population of reproductive-aged women suspected of having one or more of the following target conditions: ovarian, peritoneal or deep infiltrating endometriosis (DIE). We included studies comparing the diagnostic test accuracy of one or more blood biomarkers with the findings of surgical visualisation of endometriotic lesions.

DATA COLLECTION AND ANALYSIS

Two authors independently collected and performed a quality assessment of data from each study. For each diagnostic test, we classified the data as positive or negative for the surgical detection of endometriosis, and we calculated sensitivity and specificity estimates. We used the bivariate model to obtain pooled estimates of sensitivity and specificity whenever sufficient datasets were available. The predetermined criteria for a clinically useful blood test to replace diagnostic surgery were a sensitivity of 0.94 and a specificity of 0.79 to detect endometriosis. We set the criteria for triage tests at a sensitivity of ≥ 0.95 and a specificity of ≥ 0.50, which 'rules out' the diagnosis with high accuracy if there is a negative test result (SnOUT test), or a sensitivity of ≥ 0.50 and a specificity of ≥ 0.95, which 'rules in' the diagnosis with high accuracy if there is a positive result (SpIN test).

MAIN RESULTS

We included 141 studies that involved 15,141 participants and evaluated 122 blood biomarkers. All the studies were of poor methodological quality. Studies evaluated the blood biomarkers either in a specific phase of the menstrual cycle or irrespective of the cycle phase, and they tested for them in serum, plasma or whole blood. Included women were a selected population with a high frequency of endometriosis (10% to 85%), in which surgery was indicated for endometriosis, infertility work-up or ovarian mass. Seventy studies evaluated the diagnostic performance of 47 blood biomarkers for endometriosis (44 single-marker tests and 30 combined tests of two to six blood biomarkers). These were angiogenesis/growth factors, apoptosis markers, cell adhesion molecules, high-throughput markers, hormonal markers, immune system/inflammatory markers, oxidative stress markers, microRNAs, tumour markers and other proteins. Most of these biomarkers were assessed in small individual studies, often using different cut-off thresholds, and we could only perform meta-analyses on the data sets for anti-endometrial antibodies, interleukin-6 (IL-6), cancer antigen-19.9 (CA-19.9) and CA-125. Diagnostic estimates varied significantly between studies for each of these biomarkers, and CA-125 was the only marker with sufficient data to reliably assess sources of heterogeneity.The mean sensitivities and specificities of anti-endometrial antibodies (4 studies, 759 women) were 0.81 (95% confidence interval (CI) 0.76 to 0.87) and 0.75 (95% CI 0.46 to 1.00). For IL-6, with a cut-off value of > 1.90 to 2.00 pg/ml (3 studies, 309 women), sensitivity was 0.63 (95% CI 0.52 to 0.75) and specificity was 0.69 (95% CI 0.57 to 0.82). For CA-19.9, with a cut-off value of > 37.0 IU/ml (3 studies, 330 women), sensitivity was 0.36 (95% CI 0.26 to 0.45) and specificity was 0.87 (95% CI 0.75 to 0.99).Studies assessed CA-125 at different thresholds, demonstrating the following mean sensitivities and specificities: for cut-off > 10.0 to 14.7 U/ml: 0.70 (95% CI 0.63 to 0.77) and 0.64 (95% CI 0.47 to 0.82); for cut-off > 16.0 to 17.6 U/ml: 0.56 (95% CI 0.24, 0.88) and 0.91 (95% CI 0.75, 1.00); for cut-off > 20.0 U/ml: 0.67 (95% CI 0.50 to 0.85) and 0.69 (95% CI 0.58 to 0.80); for cut-off > 25.0 to 26.0 U/ml: 0.73 (95% CI 0.67 to 0.79) and 0.70 (95% CI 0.63 to 0.77); for cut-off > 30.0 to 33.0 U/ml: 0.62 (95% CI 0.45 to 0.79) and 0.76 (95% CI 0.53 to 1.00); and for cut-off > 35.0 to 36.0 U/ml: 0.40 (95% CI 0.32 to 0.49) and 0.91 (95% CI 0.88 to 0.94).We could not statistically evaluate other biomarkers meaningfully, including biomarkers that were assessed for their ability to differentiate endometrioma from other benign ovarian cysts.Eighty-two studies evaluated 97 biomarkers that did not differentiate women with endometriosis from disease-free controls. Of these, 22 biomarkers demonstrated conflicting results, with some studies showing differential expression and others no evidence of a difference between the endometriosis and control groups.

AUTHORS' CONCLUSIONS

Of the biomarkers that were subjected to meta-analysis, none consistently met the criteria for a replacement or triage diagnostic test. A subset of blood biomarkers could prove useful either for detecting pelvic endometriosis or for differentiating ovarian endometrioma from other benign ovarian masses, but there was insufficient evidence to draw meaningful conclusions. Overall, none of the biomarkers displayed enough accuracy to be used clinically outside a research setting. We also identified blood biomarkers that demonstrated no diagnostic value in endometriosis and recommend focusing research resources on evaluating other more clinically useful biomarkers.

Risk of developing major depression and anxiety disorders among women with endometriosis: A longitudinal follow-up study

BACKGROUNDS

Several cross-sectional studies suggested a link between endometriosis and mood disorders. However, the temporal association between endometriosis and mood disorders (depression and anxiety disorders) is still unclear.

METHODS

Using the Taiwan National Health Insurance Research Database, 10,439 women with endometriosis and 10,439 (1:1) age-/sex-matched controls between 1998 and 2009 were enrolled, and followed up to the end of 2011. Those who developed depression or anxiety disorders during the follow-up were identified.

RESULTS

Women with endometriosis had an increased risk of developing major depression (hazard ratio [HR]: 1.56, 95% confidence interval [CI]:1.24-1.97), any depressive disorder (HR: 1.44, 95% CI: 1.25-1.65), and anxiety disorders (HR: 1.44, 95% CI: 1.22-1.70) in later life compared to those without endometriosis. Stratified by age group, women with endometriosis aged <40 years and those aged ≧40 years were both prone to developing major depression (HR: 1.52, 95% CI: 1.15-1.99; HR: 1.69, 95% CI: 1.09-2.62), any depressive disorder (HR: 1.43, 95% CI: 1.21-1.69; HR: 1.45, 95% CI: 1.13-1.56), and anxiety disorders (HR: 1.39, 95% CI: 1.14-1.71; HR: 1.53, 95% CI: 1.15-2.04).

LIMITATION

the incidence of depression and anxiety disorders may be underestimated since only those who sought medical consultation and help would be enrolled in our study.

CONCLUSION

Endometriosis was associated with an elevated likelihood of developing depression and anxiety disorders. Further studies may be required to investigate the underlying pathophysiology between endometriosis and both depression and anxiety disorders.

Serum markers for the noninvasive diagnosis of endometriosis

Endometriosis is a disease that affects millions of women worldwide and its diagnosis is still challenging. Medical history, symptoms together with imaging data may address the correct diagnosis, but the gold standard remains laparoscopic assessment with histological confirmation. The development of serum markers as diagnostic tools for endometriosis may allow a prompt and noninvasive diagnosis. Several serum biomarkers have been investigated over the years, but none of these have shown a clinical utility and nowadays the more realistic diagnostic biomarker consists in a panel of biomarkers. The recent introduction of new technologies such as genomics and proteomics may represent the future perspective of endometriosis diagnosis.

Update on Biomarkers for the Detection of Endometriosis

Endometriosis is histologically characterized by the displacement of endometrial tissue to extrauterine locations including the pelvic peritoneum, ovaries, and bowel. An important cause of infertility and pelvic pain, the individual and global socioeconomic burden of endometriosis is significant. Laparoscopy remains the gold standard for the diagnosis of the condition. However, the invasive nature of surgery, coupled with the lack of a laboratory biomarker for the disease, results in a mean latency of 7–11 years from onset of symptoms to definitive diagnosis. Unfortunately, the delay in diagnosis may have significant consequences in terms of disease progression. The discovery of a sufficiently sensitive and specific biomarker for the nonsurgical detection of endometriosis promises earlier diagnosis and prevention of deleterious sequelae and represents a clear research priority. In this review, we describe and discuss the current status of biomarkers of endometriosis in plasma, urine, and endometrium.

Pro-inflammatory cytokines for evaluation of inflammatory status in endometriosis

THE AIM OF THE STUDY

The aim of the study was to investigate the serum pro-inflammatory cytokine profile in patients with diagnosed endometriosis.

MATERIAL AND METHODS

The study included 160 women, who were divided in two study groups (Group I - endometriosis; Group 2 - healthy). We evaluated the serum levels of interleukin (IL)-1β, IL-5, IL-6, IL-7, and IL-12, and of tumour necrosis factor α (TNF-α) with the use of Human Multiplex Cytokine Panels.

RESULTS

The serum level of IL-1β, IL-6, and TNF-α is significantly higher in women with endometriosis compared to women free of disease, from the control group (mean 10.777, 183.027, and 131.326, respectively, compared to 3.039, 70.043, and 75.285, respectively; p = 0.002, p < 0.001, and p = 0.015, respectively). No significant differences in the serum levels of IL-5 and IL-12 were observed between the studied groups, and IL-7 had a very low detection rate.

CONCLUSIONS

Women with endometriosis have elevated levels of key pro-inflammatory cytokines, i.e. IL-1β, IL-6, and TNF-α. At the same time, IL-1β and IL-6 could be used as predictors for endometriosis.

Diagnostic potential of peritoneal fluid biomarkers of endometriosis

Endometriosis is defined as the presence of endometrial glands and stroma outside the uterus, in different parts of the peritoneal cavity. It affects up to 10% of reproductive-age women and up to 50% of women with infertility. Surgical diagnosis of endometriosis is still the gold standard, with no diagnostic biomarkers available. Medical therapies target the symptoms and not the disease itself, and surgical treatment cannot prevent recurrence. As peritoneal fluid reflects the altered peritoneal microenvironment of endometriosis patients, it can provide a wealth of information on pathophysiological processes and potential biomarkers. This report reviews the molecular biomarkers identified in peritoneal fluid over the last 5 years and discusses their potential applications for diagnosis, prognosis and drug therapy.

Noninvasive biomarkers of endometriosis: myth or reality?

Endometriosis affects 10% of premenopausal women and 35-50% of women with infertility, pelvic pain, or both. At present, endometriosis can only be diagnosed with surgery, where laparoscopy is considered a gold standard. Noninvasive biomarkers are thus urgently needed. In 2010, the peripheral biomarkers of endometriosis were systematically reviewed by May et al. However, with the introduction of '-omics' technologies, we have witnessed immense progress in biomarker discovery, which now calls for an overview of recent studies. This report looks at potential blood and urine biomarkers of endometriosis published in the last 3 years. The current status of noninvasive diagnostic biomarkers of endometriosis is discussed, with the limitations of these studies identified and recommendations for future biomarker discovery provided.

Distinct peritoneal fluid ghrelin and leptin in infertile women with endometriosis and their correlation with interleukin-6 and vascular endothelial growth factor

OBJECTIVE

The objective of the present study was to evaluate the levels of leptin, ghrelin, interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF) in peritoneal fluid in patients with endometriosis and infertility, and study their correlation.

DESIGN AND SETTING

This cross-sectional study included women undergoing diagnostic and/or therapeutic laparoscopy for endometriosis with chief complaint of infertility and/or pain at a tertiary care hospital. Based upon laparoscopic and histopathological findings, patients were categorized as with endometriosis and no endometriosis. Of the 50 patients with infertility (age 23-41 years), 19 had endometriosis while 31 had no endometriosis. The markers were assessed using ELISA kits.

RESULTS

The median levels of leptin in patients with endometriosis (10.20 ng/mL) were higher (p = 0.04) and median levels of ghrelin in patients with endometriosis (150.4 pg/mL) were lower (p = 0.037) versus patients with no endometriosis (5.07 ng/mL and 229.6 pg/mL, respectively). The median levels of IL-6 and VEGF in patients with endometriosis were not different between the groups. The correlation analyses showed that leptin levels and IL-6 were positively correlated (p = 0.0001).

CONCLUSIONS

The results suggest that ghrelin and leptin might play a key role in pathophysiology of endometriosis, and leptin is associated with inflammation in endometriosis.

Using Symptom Scores, Lifestyle Measures and Biochemical Markers to Create a Test for Endometriosis

Purpose

The purpose of this study was to develop a test to discriminate between women suffering from pelvic pain associated with presence or absence of endometriosis, using symptom visual analogue scale (VAS) scores, demographic and lifestyle factors and known and novel plasma biomarkers.

Methods

This was a prospective cohort study. We recruited women presenting with pelvic pain symptoms and undergoing laparoscopy. They provided a plasma sample and completed a questionnaire assessing symptom VAS scores, lifestyle factors and demographic details. Plasma was assayed for 18 potential biomarkers. Logistic regression was used to develop a test to discriminate between women with pelvic pain associated with presence or absence of endometriosis.

Results

A series of 101 women were analyzed. On univariate analysis, women with endometriosis were less likely to be parous or have previously used an intrauterine contraceptive device (IUD) but have a higher weekly alcohol intake. These women had higher VAS scores for nausea and dyspareunia, and higher plasma levels of cancer antigen 125 (CA-125). The optimum logistic regression model included parity, previous IUD use, history of endometriosis, weekly alcohol intake, dyspareunia, VAS score and CA-125. This model had a sensitivity of 93%, specificity of 62% and accuracy of 83%.

Conclusions

Combining symptom scores, historical measures and CA-125 provides a reasonable means to discriminate between women with pelvic pain associated with presence or absence of endometriosis, but greater specificity is needed before such a model could replace laparoscopy.

Screening the role of pronociceptive molecules in a rodent model of endometriosis pain

Chronic pain is a major symptom in patients with endometriosis, a common gynecologic condition affecting women in their reproductive years. Although many proalgesic substances are produced by endometriosis lesions, experimental evidence supporting their relative roles is still lacking. Furthermore, it is unclear whether these proalgesic agents directly activate nociceptors to induce endometriosis pain. To determine their relative contribution to pain associated with endometriosis, we evaluated the intrathecal administration of oligodeoxynucleotides (ODNs) antisense to messenger RNA for receptors for 3 pronociceptive mediators known to be produced by the ectopic endometrium. Two weeks after the implant of autologous uterine tissue onto the gastrocnemius muscle, local mechanical hyperalgesia was observed in operated rats. Intrathecal antisense ODN targeting messenger RNA for the interleukin 6 receptor-signaling complex subunit glycoprotein 130 and the nerve growth factor tyrosine kinase receptor A, but not their mismatch ODNs, reversibly attenuated mechanical hyperalgesia at the implant site. In contrast, intrathecal antisense ODN targeting the tumor necrosis factor receptor 1, at a dose that markedly inhibited intramuscularly injected tumor necrosis factor alpha, had only a small antihyperalgesic effect in this model. These results indicate the relative contribution of pronociceptive mediators produced by ectopic endometrial tissue to endometriosis pain. The experimental approach presented here provides a novel method to evaluate for the differential contribution of mediators produced by other painful lesions as well as endometriosis lesions as targets for novel treatment of pain syndromes.

PERSPECTIVE

This article presents evidence for the relative contribution of proalgesic mediators to primary hyperalgesia displayed by rats submitted to a model of endometriosis pain. This approach can be used to identify potential targets for the treatment of endometriosis pain.

Krüppel-like factor 9 deficiency in uterine endometrial cells promotes ectopic lesion establishment associated with activated notch and hedgehog signaling in a mouse model of endometriosis

Endometriosis, a steroid hormone-dependent disease characterized by aberrant activation of estrogen receptor signaling and progesterone resistance, remains intractable because of the complexity of the pathways underlying its manifestation. We previously showed that eutopic endometria of women with endometriosis exhibit lower expression of Krüppel-like factor 9 (KLF9), a progesterone receptor coregulator in the uterus, relative to that of women without disease. Here we examined whether loss of endometrial KLF9 expression causes ectopic lesion establishment using syngeneic wild-type (WT) mice as recipients of endometrial fragments from WT and Klf9 null donors. We found significantly higher incidence of ectopic lesions with Klf9 null than WT endometria 8 weeks after tissue injection into the intraperitoneal cavity. The increased incidence of lesion establishment with Klf9 null endometria was associated with a higher expression ratio of estrogen receptor 2 isoform relative to that of estrogen receptor 1 and attenuated progesterone receptor levels in endometriotic stromal cells. PCR array analyses of Notch and Hedgehog signaling components in ectopic lesions demonstrated up-regulated expression of select genes (Jag 2, Shh, Gli1, and Stil 1) in Klf9 null lesions relative to that in WT lesions. Immunohistochemical analyses showed increased levels of Notch intracellular domain and Sonic Hedgehog proteins in Klf9 null lesions relative to that in WT lesions, confirming pathway activation. WT recipients with Klf9 null lesions displayed lower systemic levels of TNFα and IL-6 and higher soluble TNF receptor 1 than corresponding recipients with WT lesions. Our results suggest that endometrial KLF9 deficiency promotes endometriotic lesion establishment by the coincident deregulation of Notch-, Hedgehog-, and steroid receptor-regulated pathways.

The role of placental protein 14 in the pathogenesis of endometriosis

Placental protein 14 (PP-14) is the principal secretory phase product of endometrium and has been shown to inhibit cell immune function. But its role in the pathogenesis of endometriosis is controversy. The objective of this study is to determine the concentrations of PP-14 in peritoneal fluid (PF) and serum and PP-14 protein expression in endometriotic lesions in women with ovarian endometriosis (n = 75) when compared to women without endometriosis (n = 49) between day 7 and day 20 of their menstrual cycle. Concentrations of PP-14 in PF and serum as well as PP-14 protein expression in endometriotic lesions in women with and without endometriosis were evaluated by using enzyme-linked immunosorbent assay and immunohistochemical staining, respectively. Serum PP-14 concentrations were significantly increased in women with endometriosis (7.5 ± 1.4 ng/mL) compared to those in women without endometriosis (5.8 ± 0.9 ng/mL; P < .05) and statistically decreased after surgery and further reduced by using gonadotropin-releasing hormone agonist therapy (P < .05). However, the concentrations of PP-14 in PF did not reach a significant difference between women with and without endometriosis (P > .05). In women with endometriosis, scores of PP-14 protein expression in the lesions (n = 50, 2.2 [0~5.8]) were significantly correlated with serum PP-14 concentrations (n = 50, 7.6 ± 1.3 ng/mL; P < .01). Our results suggest that PP-14 may play an important role in the pathogenesis of endometriosis.

Elevated glycodelin-A concentrations in serum and peritoneal fluid of women with ovarian endometriosis

The aim of this study was to evaluate serum and peritoneal fluid (PF) glycodelin-A concentrations in women with ovarian endometriosis. Ninety-nine matched pairs of serum and PF samples were included in our study. The case group comprised 57 women with ovarian endometriosis and the control group 42 healthy women undergoing sterilization or patients with benign ovarian cysts. Glycodelin-A concentrations were measured using ELISA. Endometriosis patients had significantly higher serum and PF glycodelin-A concentrations compared to controls, and this increase was observed in both proliferative and secretory cycle phases. Glycodelin-A concentrations were more than 10-fold higher in PF than in serum and correlated with each other. Intensity and frequency of menstrual pain positively correlated with glycodelin-A concentrations. Sensitivity and specificity of glycodelin-A as a biomarker for ovarian endometriosis were 82.1% and 78.4% in serum, and 79.7% and 77.5% in PF, respectively. These results indicate that Glycodelin-A has a potential role as a biomarker to be used in combination with other, independent marker molecules.

Diagnostic accuracy of interleukin-6 levels in peritoneal fluid for detection of endometriosis

PURPOSE

To determine, with extended receiver operating characteristic (ROC) curve analysis, the diagnostic value of cytokines showing significantly different peritoneal concentrations between women with and without endometriosis.

METHODS

Multiplex cytokine concentration measurement of IL-2, IL-4, IL-6, IL-10, TNF-α and IFN-γ levels in peritoneal fluid of women with minimal to mild (n = 10) and moderate to severe (n = 26) endometriosis, and 42 controls.

RESULTS

Only IL-6 and IL-10 concentrations were significantly higher in endometriosis patients than in controls. Specifically, significantly higher IL-6 and IL-10 levels were found in moderate to severe but not in minimal to mild endometriosis as compared to controls. For evaluation of diagnostic significance, ROC analysis determined discriminating parameters for IL-6, while those calculated for IL-10 were useless. Importantly, ROC analysis for IL-6 levels limited to women with moderate to severe endometriosis showed the highest area under the curve with the sample size sufficient to achieve 90 % power of the test. Finally, extended ROC including cost of analysis for this group of patients determined the optimal cut-off leading to high specificity and positive likelihood ratio resulting in 79 % effectiveness of the test.

CONCLUSIONS

While our outcomes show moderate usefulness of peritoneal IL-6 levels in discrimination of moderate to severe endometriosis, further studies might be needed to determine the usefulness of peritoneal IL-6 levels in detection of early stages of endometriosis, as such a finding would be more relevant in clinical decision making.