Inflammatory changes of the endometrium in patients with minimal-to-moderate endometriosis**Supported in part by grants HD20025 and HD06274 from the National Institutes of Health, Washington, D.C.††Presented at the 73rd meeting of The American Fertility Society, New Orleans, Louisiana, November 2 to 5, 1992

Diagnostic significance of neutrophil to lymphocyte ratio in endometriosis: a systematic review and meta-analysis

BACKGROUND

The purpose of this systematic review and meta-analysis was to compile existing evidence on the significance of the NLR in predicting endometriosis in order to aid clinical decision-making and outcomes.

METHODS

We searched ProQuest, Web of Science, and PubMed for related studies published before January 2, 2023. Standardized mean difference (SMD) with a 95% confidence interval (CI) was reported for each outcome. Because a significant level of heterogeneity was found, we used the random-effects model to calculate pooled effects. We used Newcastle-Ottawa Scale (NOS) for quality assessment.

RESULTS

Overall, 18 article with were included in the analysis. A random-effect model revealed that patients with endometriosis had elevated levels of NLR compared to healthy controls (SMD = 0.79, 95% CI = 0.33 to 1.25, P < 0.001). Patients with endometriosis had elevated levels of NLR compared to those with other benign tumors (SMD = 0.85, 95% CI = 0.17 to 1.53, P = 0.014). In addition, NLR level of patients with stage III and IV endometriosis was not different from that of patients with stage I and II endometrioma (SMD = 0.30, 95% CI = -0.14 to 0.74, P = 0.18). However, NLR level was not different between endometriosis patients with and without peritoneal lesions (SMD = -0.12, 95% CI = -0.34to 0.10, P = 0.28), between patients with and without endometrioma (SMD = 0.20, 95% CI = -0.15 to 0.55, P = 0.26) and between endometriosis patients with and without deep lesions (SMD = 0.04, 95% CI = -0.20 to 0.28, P = 0.72). The pooled sensitivity of NLR was 0.67 (95% CI = 0.60-0.73), and the pooled specificity was 0.68 (95% CI, 0.62-0.73).

CONCLUSIONS

NLR might be utilized in clinics as a possible predictor to help clinicians diagnose endometriosis in affected women.

The Role of Dietary Fats in the Development and Treatment of Endometriosis

Endometriosis is an estrogen-dependent disease in women of childbearing age that affects approximately 5–15% of the female population. The etiology of endometriosis is complex, multifaceted, and not fully understood. In endometriosis, which is an estrogen-related chronic inflammatory condition, estrogen plays a major role in endometrial cellular growth. High estrogen levels could be another risk factor for developing endometriosis. The aim of this review is to update knowledge on the impact of dietary fats on the development of endometriosis and chronic inflammation in women with endometriosis and diet therapy. Dietary fat may be linked with the progression and development of endometriosis, but studies have been contradictory due to various issues including sample size, different study designs, and different methodological aspects. Results have shown that the risk of endometriosis may increase with a higher consumption of products rich in saturated fats, especially palmitic acid and trans-unsaturated fatty acids. Monounsaturated fats and omega-3 polyunsaturated fatty acids may likely be connected with a lower risk of developing endometriosis and with reductions in the severity of disease. Monounsaturated fats, omega-3 polyunsaturated fatty acids, and a suitable eicosapentaenoic acid to arachidonic acid ratio can be used in diet therapy to improve quality of life by reducing pain and inflammation. Further research is needed in order to fully understand the influence of dietary fats on the risk of development of this disease.

Dietary Inflammatory Index score and risk of developing endometriosis: A case–control study

The possible relationship between chronic inflammation from dietary exposure and endometriosis has not been investigated. Thus, the aim of this study was to investigate the association between the Dietary Inflammatory Index (DII®) and endometriosis. Women with endometriotic lesions were defined as cases ( n = 59), and controls ( n = 59) had no visible ectopic endometrium sites. Body mass index (BMI=weight(kg)/height(m)2) was calculated from measured height and weight and waist circumference was measured. A validated semi-quantitative food frequency questionnaire was used to calculate the DII score. Women with endometriosis were younger, thinner; and had a more pro-inflammatory diet and more pain (dysmenorrhea, chronic pelvic pain, deep dyspareunia), than controls. Women with higher DII scores (>0.86) were more likely to have endometriosis and to present with dyspareunia. Results obtained from modeling DII as a categorical variable in relation to risk of endometriosis showed a near tripling of risk (OR = 2.77; 95% CI = 1.13–6.77) for women with DII >0.86 versus those with DII ⩽ 0.86, after adjusting for age and BMI. After multivariable adjustment, women with DII > 0.86 were four times more likely to have endometriosis compared to women with DII ⩽ 0.86 (OR = 4.14; 95% CI= 1.50–11.4). In conclusion, a pro-inflammatory diet was significantly associated with endometriosis.

Uterine Lymphatic and Blood Micro-Vessels in Women with Endometriosis through the Menstrual Cycle

Purpose

Endometriosis is a common disease, associated with persistent and severe symptoms including infertility and pain, however, pathogenesis remains poorly understood. It has been hypothesized that fragments of viable endometrial tissue shed at menstruation reach the peritoneal cavity and other distant sites by retrograde menstruation and dissemination into the lymphatic system. In this study, uterine lymphatic and blood micro-vessel populations were compared in women with and without endometriosis during the menstrual cycle.

Methods

Paraffin-embedded hysterectomy specimens from premenopausal women with histologically normal endometrium (37 control and 42 endometriosis) were obtained. Immunohistochemical staining was performed with antibodies for D2–40 (lymphatic endothelium), CD31 (pan-endothelial marker), and endoglin (activated endothelial cells in angiogenesis). Lymphatic (LVD) and blood (BVD) micro-vessel density were quantified with an automated cellular imaging system using color and morphometric properties to identify micro-vessels.

Results

Subtle but significant differences in uterine BVD and LVD were detected in endometriosis. LVD was significantly increased in basal layer endometrium of endometriosis patients during the proliferative phase (mean ± SD = 54.3 ± 20.1 vs. 41.4 ± 9.9, p = 0.025). Endoglin-positive BVD was increased in the subepithelial region of endometrium in endometriosis during the secretory phase (19.3 ± 16.6 vs. 6.4 ± 8.2, p = 0.038).

Conclusions

This report for the first time demonstrates that endometrial LVD is altered in women with endometriosis and supports changes in BVD in these women. These alterations are likely to contribute to pathogenesis of endometriosis, through lymphatic spread and increased angiogenic potential of shed endometrial fragments.

Endometrial biomarkers for the non-invasive diagnosis of endometriosis

BACKGROUND

About 10% of reproductive-aged women suffer from endometriosis, which is a costly, chronic disease that causes pelvic pain and subfertility. Laparoscopy is the gold standard diagnostic test for endometriosis, but it is expensive and carries surgical risks. Currently, there are no non-invasive tests available in clinical practice that accurately diagnose endometriosis. This is the first diagnostic test accuracy review of endometrial biomarkers for endometriosis that utilises Cochrane methodologies, providing an update on the rapidly expanding literature in this field.

OBJECTIVES

To determine the diagnostic accuracy of the endometrial biomarkers for pelvic endometriosis, using a surgical diagnosis as the reference standard. We evaluated the tests as replacement tests for diagnostic surgery and as triage tests to inform decisions to undertake surgery for endometriosis.

SEARCH METHODS

We did not restrict the searches to particular study designs, language or publication dates. To identify trials, we searched the following databases: CENTRAL (2015, July), MEDLINE (inception to May 2015), EMBASE (inception to May 2015), CINAHL (inception to April 2015), PsycINFO (inception to April 2015), Web of Science (inception to April 2015), LILACS (inception to April 2015), OAIster (inception to April 2015), TRIP (inception to April 2015) and ClinicalTrials.gov (inception to April 2015). We searched DARE and PubMed databases up to April 2015 to identify reviews and guidelines as sources of references to potentially relevant studies. We also performed searches for papers recently published and not yet indexed in the major databases. The search strategies incorporated words in the title, abstract, text words across the record and the medical subject headings (MeSH).

SELECTION CRITERIA

We considered published peer-reviewed, randomised controlled or cross-sectional studies of any size that included 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).

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data from each study and performed a quality assessment. For each endometrial diagnostic test, we classified the data as positive or negative for the surgical detection of endometriosis and calculated the estimates of sensitivity and specificity. We considered two or more tests evaluated in the same cohort as separate data sets. We used the bivariate model to obtain pooled estimates of sensitivity and specificity whenever sufficient data were available. The predetermined criteria for a clinically useful test to replace diagnostic surgery was one with a sensitivity of 94% and a specificity of 79%. The criteria for triage tests were set at sensitivity at or above 95% and specificity at or above 50%, which in case of negative results rules out the diagnosis (SnOUT test) or sensitivity at or above 50% with specificity at or above 95%, which in case of positive result rules in the diagnosis (SpIN test).

MAIN RESULTS

We included 54 studies involving 2729 participants, most of which were of poor methodological quality. The studies evaluated endometrial biomarkers either in specific phases of the menstrual cycle or outside of it, and the studies tested the biomarkers either in menstrual fluid, in whole endometrial tissue or in separate endometrial components. Twenty-seven studies evaluated the diagnostic performance of 22 endometrial biomarkers for endometriosis. These were angiogenesis and growth factors (PROK-1), cell-adhesion molecules (integrins α3β1, α4β1, β1 and α6), DNA-repair molecules (hTERT), endometrial and mitochondrial proteome, hormonal markers (CYP19, 17βHSD2, ER-α, ER-β), inflammatory markers (IL-1R2), myogenic markers (caldesmon, CALD-1), neural markers (PGP 9.5, VIP, CGRP, SP, NPY, NF) and tumour markers (CA-125). Most of these biomarkers were assessed in single studies, whilst only data for PGP 9.5 and CYP19 were available for meta-analysis. These two biomarkers demonstrated significant diversity for the diagnostic estimates between the studies; however, the data were too limited to reliably determine the sources of heterogeneity. The mean sensitivities and specificities of PGP 9.5 (7 studies, 361 women) were 0.96 (95% confidence interval (CI) 0.91 to 1.00) and 0.86 (95% CI 0.70 to 1.00), after excluding one outlier study, and for CYP19 (8 studies, 444 women), they were were 0.77 (95% CI 0.70 to 0.85) and 0.74 (95% CI 0.65 to 84), respectively. We could not statistically evaluate other biomarkers in a meaningful way. An additional 31 studies evaluated 77 biomarkers that showed no evidence of differences in expression levels between the groups of women with and without endometriosis.

AUTHORS' CONCLUSIONS

We could not statistically evaluate most of the biomarkers assessed in this review in a meaningful way. In view of the low quality of most of the included studies, the findings of this review should be interpreted with caution. Although PGP 9.5 met the criteria for a replacement test, it demonstrated considerable inter study heterogeneity in diagnostic estimates, the source of which could not be determined. Several endometrial biomarkers, such as endometrial proteome, 17βHSD2, IL-1R2, caldesmon and other neural markers (VIP, CGRP, SP, NPY and combination of VIP, PGP 9.5 and SP) showed promising evidence of diagnostic accuracy, but there was insufficient or poor quality evidence for any clinical recommendations. Laparoscopy remains the gold standard for the diagnosis of endometriosis, and using any non-invasive tests should only be undertaken in a research setting. We have also identified a number of biomarkers that demonstrated no diagnostic value for endometriosis. We recommend that researchers direct future studies towards biomarkers with high diagnostic potential in good quality diagnostic studies.

Adenomyosis and reproduction

Evidence has been provided that pelvic endometriosis is significantly associated with uterine adenomyosis and that the latter constitutes the major factor of infertility in such conditions. Furthermore, it has become evident that both adenomyosis and endometriosis constitute a pathophysiological and nosological entity. Mild peritoneal endometriosis of the fertile woman and premenopausal adenomyosis of the parous and non-parous woman, as well as adenomyosis in association with endometriosis of the infertile woman, constitute a pathophysiological continuum that is characterized by the dislocation of basal endometrium. Due to the postponement of childbearing late into the period of reproduction, premenopausal adenomyosis might increasingly become a factor for infertility in addition to adenomyosis associated with endometriosis of younger women. In any event, the presence or absence of uterine adenomyosis should be examined in a sterility work-up.

Adenomyosis in endometriosis--prevalence and impact on fertility. Evidence from magnetic resonance imaging

BACKGROUND

The hypothesis is tested that there is a strong association between endometriosis and adenomyosis and that adenomyosis plays a role in causing infertility in women with endometriosis. METHODS. Magnetic resonance imaging of the uteri was performed in 160 women with and 67 women without endometriosis. The findings were correlated with the stage of the disease, the age of the women and the sperm count parameters of the respective partners.

RESULTS

The posterior junctional zone (PJZ) was significantly thicker in women with endometriosis than in those without the disease (P<0.001). There was a positive correlation of the diameter of the PJZ with the stage of the disease and the age of the patients. The PJZ was thicker in patients with endometriosis with fertile than in patients with subfertile partners. The prevalence of adenomyotic lesions in all 160 women with endometriosis was 79%. In women with endometriosis below an age of 36 years and fertile partners, the prevalence of adenomyosis was 90% (P<0.01)

CONCLUSIONS

With a prevalence of up to 90%, uterine adenomyosis is significantly associated with pelvic endometriosis and constitutes an important factor of sterility in endometriosis presumably by impairing uterine sperm transport.

Increased expression of cyclooxygenase-2 in local lesions of endometriosis patients

PROBLEM

Human endometrial glands contain the highest levels of cyclooxygenase (COX), although whether it is COX-1 and/or COX-2 has not been previously determined. Overexpression of COX-2 may result in the pathogenesis of endometriosis.

METHOD OF STUDY

Tissue sections were obtained from 28 premenopausal women undergoing laparotomy or laparoscopic surgery for benign conditions. Endometrium, ectopic endometriosis tissue and peritoneum were obtained at the time of surgery. Informed consents were obtained from all the patients participating in this study. Immunohistochemistry was performed on consecutive sections of paraffin-embedded tissue using anti-COX-2 antibody. Expressions of COX-2 mRNA in endometrium, ectopic endometriosis tissue, and peritoneum were quantitavely determined by competitive reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

In the uterus, COX-2 was localized in the endometrial epithelium. Eutopic endometrial surface epithelium contains more COX-2 than does glandular epithelium. We observed more frequent and denser COX-2 staining in the ectopic endometriosis implants when compared with eutopic endometrium. Level of COX-2 mRNA in endometriosis was increased up to five times that of eutopic endometria.

CONCLUSION

Hyper activation of COX-2 with abnormal prostaglandin generation is considered to contribute to the pathophysiology of endometriosis and disease progression.

Theories of endometriosis

Endometriosis is characterised by the presence of abnormally located tissue resembling the endometrium with glands and stroma. Several hypotheses have attempted to explain the development of such tissue. The oldest theory, that of metaplasia, suggests that under diverse influences coelomic tissue could be transformed into endometrium. The most often cited theory, that of implantation, proposes that the physiological phenomenon of endometrial reflux in the fallopian tubes during menstruation may, in certain conditions, overcome local defense mechanisms, implant, and proliferate. The peritoneal fluid in unaffected women possesses the capacity to prevent endometriotic tissue from becoming established. The reasons for the occurrence of endometriosis and its consequences (pain, sterility, adhesions) are probably numerous and involve the endometrium, the immune system (macrophages, natural killer cells), the peritoneum, and fallopian tubes. The failure to clear the peritoneal cavity of fragments of endometrium could cause a state of local inflammation with hyperactivation of macrophages secreting a variety of different compounds. Some of these compounds may bring about metaplasia of the peritoneum or the development of Mullerian residues.

Is endometriosis an endometrial disease?

Endometriosis is characterised by the presence of abnormally located tissue resembling the endometrium with glands and stroma. Several hypotheses have attempted to explain the development of such tissue. The most often cited theory, that of implantation, proposes that the physiological phenomenon of endometrial reflux in the fallopian tubes during menstruation may, in certain conditions, overcome local defense mechanisms, implant, and proliferate. The implantation theory does not explain why endometriosis will develop only in approximately 10-15% of women, while the reflux of endometrial tissue via the fallopian tubes during menstruation is a quasi-universal phenomenon. The endometrium of women affected by endometriosis could be abnormal compared with endometrium of healthy women. The abnormal endometrium could be able to protect itself from harmful effects of immune cells by expressing specific antigens, by harbouring a different immune cell population and by synthetizing and secreting immunosuppressive factors. Several others characteristic features of endometrium have been described in women with endometriosis: (1) production of its own estrogens in too heavy amount; (2) aptitude for setting up on peritoneum; (3) tendencies to proliferate and to invade tissue; (4) aggressiveness for the peritoneum; (5) auto-protection from physiological apoptosis; (6) abnormal expression of heat shock proteins; and (7) excessive angiogenesis.

Structural abnormalities of the uterine wall in women with endometriosis and infertility visualized by vaginal sonography and magnetic resonance imaging

In women with endometriosis, the peristaltic activity of the uterus is significantly enhanced and may even become dysperistaltic at midcycle. Since uterine peristalsis is confined to the endometrium and the subendometrial myometrium with its predominantly circular arrangement of muscular fibres it was assumed that this dysfunction might be associated with structural abnormalities that could be visualized by high resolution ultrasonography and magnetic resonance imaging (MRI). Therefore, the uteri of women with and without endometriosis were subjected to endovaginal sonography (EVS) and to MRI. In EVS, women with laparoscopically proven endometriosis and infertility exhibited an infiltrative expansion of the archimetra in that the halo surrounding the uterine endometrium and representing the subendometrial myometrium was significantly enlarged compared with controls. The expansion was more pronounced in older than in younger women. There was, however, no relationship between the width of the expansion and the severity of the endometriotic disease. Similar data were obtained by MRI in that the 'junctional zone' in women with endometriosis and infertility was expanded in comparison with controls. The results of this study provide further support to the notion that endometriosis is primarily a uterine disease.

RANTES production by cultured primate endometrial epithelial cells

PROBLEM

RANTES (regulated upon activation, normal T cell expressed and secreted), is a chemokine with monocyte, macrophage, T lymphocyte, and eosinophil attractant and activating activities. This mediator has been detected in the peritoneal fluid of patients with endometriosis and in cultures of stromal cells from human endometrial and endometriotic tissue. To determine if endometrial epithelial cells were also a potential source of this mediator, primate endometrial epithelial cells were cultured in vitro and the constitutive and stimulated production of RANTES in these cultures was measured.

METHOD OF STUDY

Uterine tissue was obtained from Macaca nemestrina monkeys and the endometrial epithelial cells were isolated and placed in culture for 24-72 hr. RANTES was measured in cell extracts and culture fluids by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Constitute release of RANTES was low, ranging from 28-52 ng/mL but addition of interferon gamma (INF-gamma) or the combination of IFN-gamma and tumor necrosis factor alpha (TNF-alpha) produced a marked increase in RANTES production. The greatest release, which was nearly 500-fold greater than the basal level, was observed at 72 hr with the combined addition of TNF-alpha and INF-gamma. Nearly 90% of the stimulated RANTES was released into culture fluids, while cell associated RANTES was minimal constituting only 11.2% of the total.

CONCLUSION

These findings indicate that endometrial epithelial cells can produce and release RANTES. This chemokine may be an important attractant and activator of macrophages, T lymphocytes and/or eosinophils in the uterus during the reproductive cycle or implantation.

Increased secretion of hepatocyte growth factor by eutopic endometrial stromal cells in women with endometriosis

OBJECTIVE

We evaluated the secretion of hepatocyte growth factor by eutopic endometrial stromal cells in vitro.

DESIGN

Eutopic endometrial stromal cells were isolated and the culture supernatants were collected after 48 hours of incubation. The secretion of hepatocyte growth factor was analyzed by ELISA.

SETTING

Department of Obstetrics and Gynecology of Tohoku University Hospital.

PATIENT(S)

Specimens of endometrium in the proliferative phase were excised from 11 patients who were undergoing laparoscopy for infertility. Six of the patients had endometriosis and five did not. None of the patients had received hormonal treatment before surgery.

RESULT(S)

Hepatocyte growth factor secretion was found to be increased significantly in cultured endometrial stromal cells from the infertile patients with endometriosis compared with those without endometriosis.

CONCLUSION(S)

The secretion of hepatocyte growth factor was up-regulated in eutopic endometrial stromal cells from patients with endometriosis. An increase in hepatocyte growth factor production may be characteristic of endometriosis and may be involved in the pathophysiology of this disease.