Immunopathogenesis of pelvic endometriosis: role of hepatocyte growth factor, macrophages and ovarian steroids

Increased percentage of Th17 cells in peritoneal fluid is associated with severity of endometriosis

AIM

Th17 cells are a newly discovered T helper lymphocyte subpopulation, producing interleukin IL-17. Th17 cells are present in blood and peritoneal fluid (PF) at different stages of endometriosis. We aim to establish their potential importance in the pathogenesis and clinical features of the disease.

METHODS

The percentage of Th17 cells among T helper lymphocytes was determined in the PF and peripheral blood (PB) of patients with endometriosis and in the control group by flow cytometry using monoclonal antibodies: anti-CD-4-FITC, anti-CD-3-PE/Cy5, and anti-IL-17A-PE.

RESULTS

Th17 percentage is increased in PF in comparison with PB in both endometriotic patients and in the control group. In severe endometriosis, the percentage of Th17 cells in PF was higher than with early (I/II stage) endometriosis. A positive correlation between the percentage of Th17 cells in PF and the white blood cell count in PB was found in patients with endometriosis.

CONCLUSION

Targeting the activity of PF Th17 cells may have an influence on the proliferation of ectopic tissue and clinical manifestations of the disease.

Decreased Cytotoxicity of Peripheral and Peritoneal Natural Killer Cell in Endometriosis

Endometriosis causes significant chronic pelvic pain, dysmenorrhea, and infertility and affects 10% of all women. In endometriosis, ectopic endometrium surviving after retrograde menstruation exhibits an abnormal immune response characterized by increased levels of activated macrophages and inflammatory cytokines. Particularly, dysfunctional natural killer (NK) cells play an important role in the pathogenesis of the disease by either facilitating or inhibiting the survival, implantation, and proliferation of endometrial cells. NK cells in the peritoneum and peritoneal fluid exhibit reduced levels of cytotoxicity in women with endometriosis. Several cytokines and inhibitory factors in the serum and peritoneal fluid also dysregulate NK cell cytotoxicity. Additionally, increased numbers of immature peripheral NK cells and induction of NK cell apoptosis are evident in the peritoneal fluid of women with endometriosis. The high rate of endometriosis recurrence after pharmaceutical or surgical treatment, which is associated with dysfunctional NK cells, indicates that new immunomodulatory management strategies are required. A good understanding of immune dysfunction would enable improvement of current treatments for endometriosis.

Association of the Precursor of Interleukin-1β and Peritoneal Inflammation-Role in Pathogenesis of Endometriosis

BACKGROUND

The most important proinflammatory cytokine is interleukin (IL)-1β, however its precursor, prointerleukin-1β (proIL-1β), can also potentiate inflammatory state. The aim of this study was to explore the involvement of proIL-1β in pathogenesis of endometriosis. For this purpose, we evaluated concentrations of proIL-1β, IL-1β, and soluble IL-1 receptor type 2 (sIL-1R2) in peritoneal fluid (PF) and macrophage culture medium of women with endometriosis.

METHODS

PF from 55 women with and without endometriosis was collected during laparoscopy. Peritoneal macrophages were cultured in basal and stimulated with lipopolysaccharide (LPS) conditions. Concentrations of cytokines were measured with enzyme-linked immunosorbent assays (ELISA).

RESULTS

PF proIL-1β and IL-1β levels in endometriosis women were higher than in the control. Higher basal and stimulated macrophage secretion of cytokines in endometriosis patients than in the control was observed. However, in endometriosis, there was a higher level of proIL-1β than for the mature molecule. Additionally, lower PF and macrophages culture medium sIL-1R2 levels were observed in women with endometriosis.

CONCLUSIONS

Abnormal proIL-1β concentration in PF and higher macrophage secretion can escalate peritoneal inflammation and endometriosis formation. The results are presented as a total IL-1β, which is a sum of proIL-1β  and IL-1β, and we believe that it reflects the actual cytokine production. The imbalance among all studied cytokines in endometriosis may be linked with an ability to transform acute inflammation to the chronic inflammation.

VASCULAR ENDOTHELIAL GROWTH FACTOR SERUM LEVELS IN WOMEN WITH ADVANCED ENDOMETRIOSIS

CONTEXT

Endometriosis is a common gynecological disease, characterized by ectopic deposits of endometrial tissue outside of the uterine cavity, and it is associated with pelvic pain and infertility, with an important impact on the quality of life. At this point there is a controversy regarding the etiology and pathophysiology of endometriosis and it seems that pro-angiogenic growth factors might be involved, but their role is not completely understood.

OBJECTIVE

To evaluate the serum concentration of the main growth factors in patients with diagnosed endometriosis compared to healthy controls.

SUBJECTS AND METHODS

A total of 157 women were divided into two study groups (Group I - endometriosis; Group 2 - healthy women). Serum levels of VEGF, G-CSF, GM-CSF, b-FGF, EGF, and HGF were measured with Human Multiplex Cytokine Panels.

RESULTS

VEGF serum levels were significantly lower in women with endometriosis compared to controls (1.924±0.145 compared to 1.806±0.078 pg/mL, p<0.001). Serum levels of GM-CSF, b-FGF, EGF, and HGF respectively did not differ significantly between patients with endometriosis and healthy controls. G-CSF had a very low detection rate.

CONCLUSIONS

The present study showed that VEGF serum levels are significantly lower in endometriosis patients compared to healthy controls, indicating a possible role in endometriosis pathogenesis.

Role of Bacterial Contamination in Endometriosis

The human lower genital tract is constantly exposed to various microorganisms, which can infect the upper genital tract through ascending migration. We report on tests of the hypothesis that as normal microbial flora in the vagina, some gram-negative bacteria infect the uterine wall after ascending migration from the vagina, to contaminate menstrual blood, consequently resulting in accumulation of endotoxin in the menstrual/peritoneal fluid and initiation of pelvic inflammation. The aim of the present review is to assess possible intrauterine microbial colonization and to examine the stimulatory effect of E. coli-derived lipopolysaccharide (LPS) on the secretion of various macromolecules by macrophages (Mϕ) known to be involved in endometriosis. We also assess the growth-promoting effect of LPS on endometrial cells and the role of Toll-like receptor 4 (TLR4), a receptor recognizing LPS, in the secretion of macromolecules by Mϕ and growth of endometrial cells. We found higher intrauterine microbial colonization in women with endometriosis than in controls. The ligand from gram-negative bacteria is involved in TLR4-mediated proinflammation in the pelvis as well as growth of endometriosis. Treatment with gonadotropin-releasing hormone agonist (GnRHa) further promotes intrauterine microbial colonization compared with GnRHa-untreated women.

Conclusions

We propose the bacterial contamination hypothesis as a new concept in endometriosis. Based on our current findings, an estrogen-suppressing agent and an antimicrobial agent may have new therapeutic potential in women with endometriosis.

Morphologic Features Suggestive of Endometriosis in Nondiagnostic Peritoneal Biopsies

Endometriosis is a common disorder that causes significant morbidity from dysmenorrhea, pelvic pain, and subfertility. Establishment of a definitive diagnosis has important therapeutic implications; however, only approximately 50% of biopsies of laparoscopically suspicious areas provide a diagnosis of endometriosis. Histologic criteria for diagnosis require the presence of endometrial glands or endometrial-type stroma. We hypothesize that other frequently present, but nondiagnostic, histologic features of endometriosis suggest its presence in patients with nondiagnostic peritoneal biopsies. We performed a retrospective clinicopathologic study of morphologic and immunohistochemical features that may improve the histologic diagnosis of endometriosis on laparoscopic peritoneal biopsies. We compared diagnostic (n=88) and nondiagnostic (n=54) peritoneal biopsies from pathologically confirmed endometriosis cases with negative peritoneal biopsies (n=84) from early-stage gynecologic cancer cases. Statistical analysis utilized the Fisher exact test. Multiple morphologic features were significantly increased in nondiagnostic biopsies from patients with endometriosis in comparison with those from negative controls, including foamy macrophages (P=0.0001) and submesothelial stromal clusters (SSCs) (P=0.0008). SSCs ranged from subtle aggregates of spindle cells to nodules of whorled spindle cells with small vessels and extravasated red blood cells resembling stromal endometriosis. Immunohistochemical studies confirmed that ER and CD10-positive SSCs were present in a greater proportion of both nondiagnostic and diagnostic peritoneal biopsies and at a greater number of lesions per biopsy. The overall histologic detection rate of peritoneal biopsies for endometriosis was 62.0%, and inclusion of SSCs with or without foamy macrophages in the diagnostic criteria appreciably increased this rate to between 72.5% and 76.8%. We describe SSCs, which appear to be an early or less developed form of stromal endometriosis, and, when included in the diagnostic criteria, improve the histologic detection rate of endometriosis in peritoneal biopsies.

MAP kinases and the inflammatory signaling cascade as targets for the treatment of endometriosis?

INTRODUCTION

The pathogenesis of endometriosis, a common benign disease, remains ill-defined, although it is clear that chronic inflammation plays a crucial role through mitogen-activated protein kinase (MAPK) signaling pathways. All current medical therapies for endometriosis are antigonadotropic, and therefore have a contraceptive effect. A concerted research effort is hence warranted with the aim of delivering novel therapeutics that reduces disease symptoms without blocking ovulation.

AREAS COVERED

The authors review the complex pathogenic mechanisms of chronic inflammation in endometriosis and their relationships with MAPK pathways. The authors conducted a literature search of descriptive and functional targeted validation of MAPK in the pathogenesis of endometriosis. The effects of MAPK inhibitors, which constitute potential agents for future treatments, are also described.

EXPERT OPINION

Preliminary studies have highlighted a crucial role for MAPK in driving endometriosis-related inflammation. MAPK inhibitors exhibit potent activity in terms of controlling growth of endometriosis lesions both in vitro and in animal models. As MAPK inhibitors are known to have a multitude of undesirable side effects, their use in humans has to be approached with great care. Indeed, use of these drugs would probably be limited to short exposures prior to surgery in cases involving the most severe disease phenotypes.

Enhanced epithelial to mesenchymal transition (EMT) and upregulated MYC in ectopic lesions contribute independently to endometriosis

BACKGROUND

Epithelial to mesenchymal transition (EMT) is a process in which epithelial cells lose polarity and cell-to-cell contacts and acquire the migratory and invasive abilities of mesenchymal cells. These abilities are thought to be prerequisites for the establishment of endometriotic lesions. A hallmark of EMT is the functional loss of E-cadherin (CDH1) expression in epithelial cells. TWIST1, a transcription factor that represses E-cadherin transcription, is among the EMT inducers. SNAIL, a zinc-finger transcription factor, and its close relative SLUG have similar properties to TWIST1 and are thus also EMT inducers. MYC, which is upregulated by estrogens in the uterus by an estrogen response cis-acting element (ERE) in its promoter, is associated with proliferation in endometriosis. The role of EMT and proliferation in the pathogenesis of endometriosis was evaluated by analyzing TWIST1, CDH1 and MYC expression.

METHODS

CDH1, TWIST1, SNAIL and SLUG mRNA expression was analyzed by qRT-PCR from 47 controls and 74 patients with endometriosis. Approximately 42 ectopic and 62 eutopic endometrial tissues, of which 30 were matched samples, were collected during the same surgical procedure. We evaluated TWIST1 and MYC protein expression by immunohistochemistry (IHC) in the epithelial and stromal tissue of 69 eutopic and 90 ectopic endometrium samples, of which 49 matched samples were analyzed from the same patient. Concordant expression of TWIST1/SNAIL/SLUG and CDH1 but also of TWIST1 and MYC was analyzed.

RESULTS

We found that TWIST1, SNAIL and SLUG are overexpressed (p < 0.001, p = 0.016 and p < 0.001) in endometriosis, while CDH1 expression was concordantly reduced in these samples (p < 0.001). Similar to TWIST1, the epithelial expression of MYC was also significantly enhanced in ectopic endometrium compared to eutopic tissues (p = 0.008). We found exclusive expression of either TWIST1 or MYC in the same samples (p = 0.003).

CONCLUSIONS

Epithelial TWIST1 is overexpressed in endometriosis and may contribute to the formation of endometriotic lesions by inducing epithelial to mesenchymal transition, as CDH1 was reduced in ectopic lesions. We found exclusive expression of either TWIST1 or MYC in the same samples, indicating that EMT and proliferation contribute independently of each other to the formation of endometriotic lesions.

17β-estradiol and lipopolysaccharide additively promote pelvic inflammation and growth of endometriosis

Endometriosis is a multifactorial disease mostly affecting women of reproductive age. An additive effect between inflammation and stress reaction on the growth of endometriosis has been demonstrated. Here we investigated the combined effect between 17β-estradiol (E2) and lipopolysaccharide (LPS) on pelvic inflammation and growth of endometriotic cells. Peritoneal fluid was collected from 46 women with endometriosis and 30 control women during laparoscopy. Peritoneal macrophages (Mφ) and stromal cells from eutopic/ectopic endometrial stromal cells (ESCs) were isolated from 10 women each with and without endometriosis in primary culture. Changes in cytokine secretion (interleukin 6 [IL-6] and tumor necrosis factor α [TNF-α]) by Mφ and proliferation of ESCs in response to single and combined treatment with E2 and LPS were measured by enzyme-linked immunosorbent assay and by bromodeoxyuridine incorporation assay, respectively. A significantly increased secretion of IL-6 and TNF-α in Mφ culture media was found in response to E2 (10(-8) mol/L) compared to nontreated Mφ. This effect of E2 was abrogated after pretreatment of cells with ICI 182720 (10(-6) mol/L; an estrogen receptor [ER] antagonist). Combined treatment with E2 and LPS (10 ng/mL) additively promoted IL-6 and TNF-α secretion by peritoneal Mφ and growth of eutopic/ectopic ESCs. The additive effects of E2 + LPS on cytokine secretion and growth of ESCs were effectively suppressed after combined blocking of ER and Toll-like receptor 4. An additive effect was observed between E2 and LPS on promoting proinflammatory response in pelvis and growth of endometriosis.

An increased level of IL-6 suppresses NK cell activity in peritoneal fluid of patients with endometriosis via regulation of SHP-2 expression

STUDY QUESTION

Is the decreased natural killer (NK) cell cytolytic activity in the peritoneal fluid (PF) of endometriosis patients due to primary cytokine activity?

SUMMARY ANSWER

An increased level of interleukin-6 (IL-6) in the PF of patients with endometriosis suppresses NK cell cytolytic activity by down-regulating cytolytic granule components, such as granzyme B and perforin, through the modulation of Src homology region 2-containing protein tyrosine phosphatase-2 (SHP-2) expression.

WHAT IS ALREADY KNOWN

Endometriosis is known to be related to a defect in NK cell cytolytic activity. Additionally, the levels of inflammatory cytokines are elevated in the PF of women with endometriosis.

STUDY DESIGN, SIZE, DURATION

The effects of PF on the differentiation and functional activity of NK cells were investigated in patients with or without endometriosis, and cytokines that reduce NK cell cytolytic activity in endometriosis patients were examined. The study included women who underwent laparoscopic examination for the diagnosis of endometriosis from August 2012 to July 2013 (33 women with, and 15 women without, endometriosis).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Women of reproductive age (20-40 years old) who underwent laparoscopic examination for endometriosis were included. Cytokines present in the PF were identified by enzyme-linked immunosorbent assay. The cytolytic activity of NK cells in the PF was also analyzed using a calcein-acetoxy methyl ester (AM) release assay.

MAIN RESULTS AND THE ROLE OF CHANCE

PF from patients with endometriosis suppressed the differentiation and cytotoxicity of NK cells compared with PF from controls (P < 0.05). Increased levels of IL-6 were also found in the PF of patients with endometriosis (P < 0.01), and IL-6 levels were negatively correlated with the cytolytic activity of NK cells (rs = -0.558, P = 0.03). Furthermore, IL-6 reduced the cytolytic activity of NK cells, concomitantly with the down-regulation of granzyme B and perforin (P < 0.05), by modulating SHP-2. Importantly, the addition of anti-IL-6 to the PF of endometriosis patients restored the activity of NK cells (P < 0.01), suggesting that IL-6 plays a crucial role in the reduction of NK cell activity in the PF of patients with endometriosis.

LIMITATIONS, REASONS FOR CAUTION

PF contains various inflammatory cytokines in addition to IL-6 and so it is possible that other cytokines may affect the differentiation and activity of NK cells.

WIDER IMPLICATIONS OF THE FINDINGS

Our results imply that the suppression of IL-6 using an anti-IL-6 antibody or soluble IL-6 receptor could rescue the impairment of NK cell activity in patients with endometriosis.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by the KRIBB Creative Research Program (KCS3051312); the STP project (DTM0111221) of the Ministry of Knowledge & Economy and the Basic Science Research Program (RBM0271312) of the National Research Foundation of Korea (NRF) from the Ministry of Education, Science & Technology. There are no conflicts of interest.

Endometrial CXCL13 expression is cycle regulated in humans and aberrantly expressed in humans and Rhesus macaques with endometriosis

C-X-C ligand 13 (CXCL13), a regulator of mucosal immunity, is secreted by human endometrial epithelium and may be involved in embryo implantation. However, cyclic expression of human endometrial CXCL13 in health and disease is not well studied. This study examines cycle stage-specific endometrial CXCL13 expression in normal humans when compared to those with biopsy-confirmed, stage 1 to 4 endometriosis using real-time reverse transcriptase, real-time polymerase chain reaction and immunohistochemistry. Eutopic endometrial CXCL13 expression was also compared between normal, control Rhesus macaques, and macaques with advanced endometriosis. In healthy women, CXLC13 messenger RNA expression was minimal in the proliferative phase and maximal in the secretory phase. However, in the presence of endometriosis, proliferative-phase endometrial expression markedly increased in both humans and rhesus subjects (P < .05). The cross-species and cross-stage concordance suggests a pathophysiologic role for CXCL13 in endometriosis and its use as a biomarker for disease.

IL-1β increases expression of tryptophan 2,3-dioxygenase and stimulates tryptophan catabolism in endometrioma stromal cells

PROBLEM

Immune tolerance to endometriotic cells is important to promote endometriosis. Tryptophan 2,3-dioxygenase (TDO) enhances immune tolerance by catabolizing tryptophan to kynurenine. We studied whether interleukin-1β (IL-1β), a typical endometriosis-associated cytokine, affects the expression of TDO and the catabolism of tryptophan in endometrioma stromal cells (ESCs). We also studied whether the expression of TDO is involved in IL-1β-induced secretion of IL-6 and IL-8 in ESCs.

METHOD OF STUDY

Nineteen endometriotic patients of reproductive age with normal menstrual cycles were recruited. Primary cultures of ESCs were treated with IL-1β and TDO siRNA. TDO mRNA was measured using quantitative PCR. TDO protein was measured using Western blotting. Concentrations of kynurenine in condition media were measured using Ehrlich reagent. Concentrations of tryptophan in conditioned media were measured using tryptophan detection kit. Concentrations of IL-6 and IL-8 in conditioned media were measured using ELISA kits.

RESULTS

IL-1β (1 ng/mL) increased the expression of TDO mRNA and TDO protein in ESCs. IL-1β-treated ESCs increased the production of kynurenine and the effect was inhibited by TDO siRNA. Treatment with the siRNA also decreased IL-1β-induced secretion of IL-6 and IL-8 from ESCs.

CONCLUSION

IL-1β is suggested to stimulate tryptophan catabolism and production of IL-6 and IL-8 by increasing TDO expression in endometriosis.

Dienogest improves human leucocyte antigen-DR underexpression and reduces tumour necrosis factor-α production in peritoneal fluid cells from women with endometriosis

OBJECTIVE

To determine the immunological effect of dienogest (DNG), an oral anti-endometriosis drug, on peritoneal fluid (PF) macrophages collected from women with endometriosis. Although it has been suggested that DNG has direct effects on endometriotic cells, including decreased cell proliferation and decreased anti-inflammatory cytokine production, the effects of DNG on PF cells are unclear.

STUDY DESIGN

The effects of DNG on PF cells from 34 women with endometriosis and 22 women without endometriosis (controls) were investigated. Expression of human leucocyte antigen (HLA)-DR in PF macrophages, obtained from the peritoneal cavity during laparoscopic surgery, was determined by flow cytometry. HLA-DR expression was measured again after PF cells had been cultured for 72 h in a humidified atmosphere at 37 °C in 5% CO₂-95% air with or without DNG. After 72 h of incubation, the concentration of pro-inflammatory tumour necrosis factor (TNF)-α in the media was measured by enzyme-linked immunosorbent assay.

RESULTS

HLA-DR expression was lower in PF macrophages from women with endometriosis compared with controls. However, after DNG treatment, HLA-DR expression in PF macrophages from women with endometriosis was increased to the same level as in controls. The TNF-α concentration in the media was decreased by DNG.

CONCLUSIONS

DNG can restore the antigen-presenting ability of PF macrophages by increased HLA-DR expression, and may have an anti-inflammatory effect on PF macrophages in women with endometriosis.

Macrophages: are they involved in endometriosis, abortion and preeclampsia and how?

Macrophages hold a key role in both regulating and executing the body's own immune response under various conditions. Hence, although endometriosis, preeclampsia and abortions are clinically different, all three are regarded to involve highly complex immunological processes. The aim of our current work was to evaluate the role of macrophages within these gynaecological disorders. Macrophages have been shown to invade endometriosis lesions and to mediate propagation of endometriotic cyst growth. However this is the first time that significant GPER up-regulation in macrophages is demonstrated. This highlights a potential alternative way through which estrogen may modulate immune response of macrophages in endometriosis. In addition, during spontaneous miscarriages the macrophage population increases significantly. This deregulation may possibly support an inflammatory scheme further triggering abortive procedures. Macrophage-mediated apoptosis of extravillous trophoblasts (EVT) has been associated with preeclampsia. Larger numbers of apoptotic EVT were detected in preeclamptic placentas compared with normal. In preeclamptic placentas, decidual macrophages were found to be Fas ligand (FasL)-positive. Our results highlight a new aspect of macrophage biology in endometriosis and pregnancy physiology and patho-physiology. Further studies with larger samples are needed to verify the current results and evaluate their clinical impact. Our data strongly indicate that macrophages hold key roles in various gynaecological disorders and might be crucial to further elucidate their patho-physiology.

Occult microscopic endometriosis: undetectable by laparoscopy in normal peritoneum

STUDY QUESTION

Is there any occurrence of hidden (occult) endometriotic lesions in normal peritoneum of women with and without visible endometriosis?

SUMMARY ANSWER

We detected a slightly higher occurrence of occult microscopic endometriosis (OME) in normal peritoneum of women with visible endometriosis than in control women.

WHAT IS KNOWN ALREADY

Based on a small number of cases, the concept of invisible microscopic endometriosis in visually normal peritoneum has been reported for more than a decade but there is controversy regarding their tissue activity and clinical significance.

STUDY DESIGN, SIZE, DURATION

This case-controlled research study was conducted with prospectively collected normal peritoneal samples from 151 women with and 62 women without visible endometriosis.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Normal peritoneal biopsy specimens from different pelvic sites of were collected during laparoscopy. A histological search of all peritoneal biopsy specimens for the detection of invisible endometriosis was done by immunoreaction to Ber-EP4 (epithelial cell marker), CD10 (stromal cell marker) and Calretinin (mesothelial cell marker). Tissue expression of estrogen/progesterone receptors (ER/PR) and cell proliferation marker, Ki-67, was performed by immunohistochemistry to identify tissue activity.

MAIN RESULTS AND THE ROLE OF CHANCE

Three different patterns of OME were detected based on (I) the presence of typical gland/stroma, (II) reactive hyperplastic change of endometrioid epithelial cells with surrounding stroma and (III) single-layered epithelium-lined cystic lesions with surrounding stroma. A higher tendency toward the occurrence of OME was found in women with visible endometriosis (15.2%, 23/151) compared with control women (6.4%, 4/62) (P = 0.06, χ(2) test). The epithelial cells and/or stromal cells of OME lesions were immunoreactive to Ber-EP4 and CD10 but not reactive to Calretinin. ER and PR expression was observed in all patterns of OME lesions. Ki-67 index was significantly higher in pattern I/II OME lesions than in pattern III OME lesions (P< 0.05 for each).

LIMITATIONS, REASONS FOR CAUTION

Bias in the incidence rate of OME lesions in this study cannot be ignored, because we could not analyze biopsy specimens from the Pouch of Douglas of women with revised classification of the American Society of Reproductive Medicine Stage III-IV endometriosis due to the presence of adhesions in the pelvis.

WIDER IMPLICATIONS OF THE FINDINGS

We re-confirmed a decade long old concept of invisible (occult) endometriosis in visually normal peritoneum of women with visible endometriosis. The existence of a variable amount of tissue activity in these occult lesions may contribute to the recurrence/occurrence of endometriosis or persistence/recurrence of pain manifestation in women even after successful ablation or excision of visible lesions by laparoscopy.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported in part by Grants-in-aid for Scientific Research from the Japan Society for the Promotion of Science. There is no conflict of interest related to this study.

TRIAL REGISTRATION NUMBER

Not applicable.

Evaluation of mean platelet volume, neutrophil/lymphocyte ratio and platelet/lymphocyte ratio in advanced stage endometriosis with endometrioma

OBJECTIVE

We compared the preoperative values of mean platelet volume (MPV) and peripheral systemic inflammatory response (SIR) markers (neutrophil/lymphocyte ratio and platelet/lymphocyte ratio) between patients with advanced-stage (stage 3/4) endometriosis having endometrioma (OMA) and patients with a non-neoplastic adnexal mass other than endometrioma (non-OMA).

MATERIAL AND METHODS

Patients who underwent operations with the pre-diagnosis of infertility or adnexal mass and who underwent laparoscopic tubal ligation were included.

RESULTS

Haemoglobin levels, leucocyte count, platelet count, neutrophil count and lymphocyte count were not significantly different between patients with advanced stage endometriosis having OMA, patients with non-OMA and patients in the control group (p=0.970, p=0.902, p=0.373, p=0.501 and p=0.463, respectively). Patients with stage 3/4 endometriosis having OMA, patients with non-OMA and control patients were also not significantly different in terms of MPV (p=0.836), neutrophil/lymphocyte ratio (NLR) (p=0.555) and platelet/lymphocyte ratio (PLR) (p=0.358). Preoperative cancer antigen 125 (Ca-125) levels were significantly higher in patients with OMA (p=0.006). Mean size of the OMAs was significantly lower than non-OMAs (p=0.000).

CONCLUSION

It is very important to determine advanced stage endometriosis and OMAs during preoperative evaluation in order to inform patients and plan an appropriate surgical approach. We demonstrate that MPV, NLR and PLR values are not useful for this purpose in patients with advanced stage endometriosis that are proven to develop severe inflammation at either the cellular or molecular level.

Soluble c-Met expression in the peritoneal fluid and serum of patients with different stages of endometriosis

INTRODUCTION

Hepatocyte growth factor (HGF), also known as scatter factor, and its receptor c-Met have been shown to be implicated in endometriosis. HGF acts as a mitogen, motogen, and morphogen on endometrial epithelial cells. The expression of c-Met on human endometrial cells has been reported. Many proteins are proteolytically released from the surface by a process known as ectodomain shedding. The aim of this study was to determine the levels of soluble c-Met (s-cMet) in the peritoneal fluid (PF) and serum samples of patients with different stages of endometriosis.

MATERIAL AND METHODS

39 PF and serum samples from normal healthy and 130 samples from different stages of patients with endometriosis (33 cases of stage I, 38 stage II, 30 stage III and 29 stage IV) were included in this study. Total protein concentration (TPC) and the level of s-cMet in the PF and serum were determined by Bio-Rad protein assay based on the Bradford dye procedure and enzyme-linked immunosorbent assay, respectively.

RESULTS

No significant change in the TPC was seen in the serum and PF of patients with endometriosis when compared with normal controls. Results obtained demonstrated that all PF and serum samples presented s-cMet expression, whereas, starting from stages I to IV endometriosis, a significant increase of s-cMet expression was observed as compared to controls.

CONCLUSION

The results of this study show that a high expression of s-cMet is correlated with advanced stages of endometriosis. It is also concluded that the detection of serum and PF s-cMet may be useful in classifying endometriosis.

Toll-like receptor system and endometriosis

Endometriosis is an estrogen-dependent chronic inflammatory condition associated with variable degrees of pelvic pain and infertility. Studies have showed that the growth and progression of endometriosis continue even in ovariectomized animals. This indicates that besides ovarian steroid hormones, the growth of endometriosis can be regulated by the innate immune system in the pelvic environment. As a component of innate immune system, increased infiltration of macrophages has been described in the intact tissue and peritoneal fluid of women with endometriosis. Different immune cells and dendritic cells express Toll-like receptors (TLR) and exhibit functional activity in response to microbial products. In this review article, we discuss the role of the TLR system in endometrium and endometriosis and outline the involvement of cytokines/endotoxin in causing adverse reproductive outcome. In the first part of this review article, the fundamentals of innate immune system, functional characteristics of TLR and signaling pathways of TLR4 are discussed for easy understanding by the readers.

Additive effects of inflammation and stress reaction on Toll-like receptor 4-mediated growth of endometriotic stromal cells

STUDY QUESTION

Is there any combined effect between inflammation and stress reaction on Toll-like receptor 4 (TLR4)-mediated growth of endometriotic cells?

SUMMARY ANSWER

A combined effect of local inflammation and stress reaction in the pelvic environment may be involved in TLR4-mediated growth of endometriotic stromal cells.

WHAT IS KNOWN ALREADY

In endometriosis, higher endotoxin levels in the menstrual fluid (MF) and peritoneal fluid (PF) and higher tissue concentrations of human heat shock protein 70 (HSP70) in the eutopic and ectopic endometria promote TLR4-mediated growth of endometriotic cells.

STUDY DESIGN, SIZE AND DURATION

This is a case-controlled research study with prospective collection and retrospective evaluation of sera, MF, PF and endometrial tissues from 43 women with and 20 women without endometriosis.

PARTICIPANTS/MATERIALS, SETTING, METHODS

PF was collected from 43 women with endometriosis and 20 control women during laparoscopy. Sera and endometrial biopsy specimens were collected from a proportion of these women. MF was collected from a separate population of 20 women with endometriosis and 15 control women. HSP70 concentrations in sera, MF, PF and in culture media were measured by ELISA. Gene expression of HSP70 by endometrial cells in response to lipopolysaccharide (LPS) was examined by qRT-PCR. The individual and combined effects of LPS and HSP70 on the secretion of interleukin-6 (IL-6) and tumor necrosis factor α (TNFα) by PF-derived macrophages (M[Symbol: see text]) were examined by ELISA, while their effects on endometrial cell proliferation were examined by bromodeoxyuridine and [(3)H]-thymidine incorporation assay.

MAIN RESULTS AND THE ROLE OF CHANCE

Concentrations of HSP70 were maximal in MF, intermediate in PF and the lowest in sera. In MF and PF, HSP70 levels were higher in women with endometriosis than in controls. LPS stimulated gene expression and secretion of HSP70 by eutopic endometrial stromal cells (ESCs) and this effect was abrogated after pretreatment of cells with an anti-TLR4 antibody. This effect was significantly higher for ESCs derived from women with endometriosis than for ESCs from control women. Exogenous treatment with either HSP70 or LPS significantly stimulated the production of IL-6 and TNFα by M[Symbol: see text] and promoted the proliferation of ESCs, and a significant additive effect between LPS and HSP70 was observed. While individual treatment with either polymyxin B, an LPS antagonist, or anti-HSP70 antibody was unable to suppress the combined effects of LPS and HSP70 on cytokine secretion or ESC proliferation, pretreatment of cells with the anti-TLR4 antibody was able to significantly suppress their combined effects.

LIMITATIONS, REASONS FOR CAUTIONS

Further studies are needed to examine the mutual role between other secondary inflammatory mediators and endogenous stress proteins in promoting pelvic inflammation and growth of endometriotic stromal cells.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings suggest that endotoxin and HSP70 are mutually involved in a stress reaction and in inflammation. A combined effect between local inflammation and a stress reaction in pelvic environment may be involved in TLR4-mediated growth of endometriotic cells. Since endometriosis is a multi-factorial disease, it is difficult to explain uniformly its growth regulation by a single factor. Our findings may provide some new insights in understanding the physiopathology or pathogenesis of endometriosis and may hold new therapeutic potential.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by Grants-in-Aid for Scientific Research (grant no. 16591671 and 18591837) from the Ministry of Education, Sports, Culture, Science and Technology of Japan (to K.N.K.). There is no conflict of interest related to this study.

TRIAL REGISTRATION NUMBER

Not applicable.

Interplay between Misplaced Müllerian-Derived Stem Cells and Peritoneal Immune Dysregulation in the Pathogenesis of Endometriosis

In the genetic regulation of Müllerian structures development, a key role is played by Hoxa and Wnt clusters, because they lead the transcription of different genes according to the different phases of the organogenesis, addressing correctly cell-to-cell interactions, allowing, finally, the physiologic morphogenesis. Accumulating evidence is suggesting that dysregulation of Wnt and/or Hox genes may affect cell migration during organogenesis and differentiation of Müllerian structures of the female reproductive tract, with possible dislocation and dissemination of primordial endometrial stem cells in ectopic regions, which have high plasticity to differentiation. We hypothesize that during postpubertal age, under the influence of different stimuli, these misplaced and quiescent ectopic endometrial cells could acquire new phenotype, biological functions, and immunogenicity. So, these kinds of cells may differentiate, specializing in epithelium, glands, and stroma to form a functional ectopic endometrial tissue. This may provoke a breakdown in the peritoneal cavity homeostasis, with the consequent processes of immune alteration, documented by peripheral mononuclear cells recruitment and secretion of inflammatory cytokines in early phases and of angiogenic and fibrogenic cytokines in the late stages of the disease.

Role of prostaglandin E2 in bacterial growth in women with endometriosis

STUDY QUESTION

Can prostaglandin E(2) (PGE(2)) in menstrual and peritoneal fluid (PF) promote bacterial growth in women with endometriosis?

SUMMARY ANSWER

PGE(2) promotes bacterial growth in women with endometriosis.

WHAT IS KNOWN ALREADY

Menstrual blood of women with endometriosis is highly contaminated with Escherichia coli (E. coli) compared with that of non-endometriotic women: E. coli-derived lipopolysaccharide (LPS) promotes the growth of endometriosis.

STUDY DESIGN, SIZE AND DURATION

Case-controlled biological research with a prospective collection of body fluids and endometrial tissues from women with and without endometriosis with retrospective evaluation.

PARTICIPANTS/MATERIALS, SETTING AND METHODS

PF and sera were collected from 58 women with endometriosis and 28 women without endometriosis in an academic research laboratory. Menstrual blood was collected from a proportion of these women. Macrophages (Mφ) from PF and stromal cells from eutopic endometria were isolated in primary culture. The exogenous effect of PGE(2) on the replication of E. coli was examined in a bacterial culture system. Levels of PGE(2) in different body fluids and in the culture media of Mφ and stromal cells were measured by ELISA. The effect of PGE(2) on the growth of peripheral blood lymphocytes (PBLs) was examined.

MAIN RESULTS AND THE ROLE OF CHANCE

The PGE(2) level was 2-3 times higher in the menstrual fluid (MF) than in either sera or in PF. A significantly higher level of PGE(2) was found in the MF and PF of women with endometriosis than in control women (P < 0.05 for each). Exogenous treatment with PGE(2) dose dependently increased E. coli colony formation when compared with non-treated bacteria. PGE(2)-enriched MF was able to stimulate the growth of E. coli in a dilution-dependent manner; this effect was more significantly enhanced in women with endometriosis than in control women (P < 0.05). PGE(2) levels in the culture media of LPS-treated Mφ/stromal cells were significantly higher in women with endometriosis than in non-endometriosis (P < 0.05 for each). Direct application of PGE(2) and culture media derived from endometrial Mφ or stromal cells significantly suppressed phytohemagglutinin-stimulated growth of PBLs.

LIMITATIONS AND REASONS FOR CAUTION

Further studies are needed to examine the association between PGE(2)-stimulated growth of E. coli and endotoxin level and to investigate the possible occurrence of sub-clinical infection within vaginal cavity.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings may provide some new insights to understand the physiopathology or pathogenesis of the mysterious disease endometriosis and may hold new therapeutic potential.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by grants-in-aid for Scientific Research from the Ministry of Education, Sports, Culture, Science and Technology of Japan. There is no conflict of interest related to this study.

TRIAL REGISTRATION NUMBER

Not applicable.

Role of estrogen receptor signaling required for endometriosis-like lesion establishment in a mouse model

Endometriosis results from ectopic invasion of endometrial tissue within the peritoneal cavity. Aberrant levels of the estrogen receptor (ER), ERα and ERβ, and higher incidence of autoimmune disorders are observed in women with endometriosis. An immunocompetent mouse model of endometriosis was used in which minced uterine tissue from a donor was dispersed into the peritoneal cavity of a recipient. Wild-type (WT), ERα-knockout (αERKO), and βERKO mice were donors or recipients to investigate the roles of ERα, ERβ, and estradiol-mediated signaling on endometriosis-like disease. Mice were treated with vehicle or estradiol, and resulting location, number, and size of endometriosis-like lesions were assessed. In comparison with WT lesions in WT hosts, αERKO lesions in WT hosts were smaller and fewer in number. The effect of ER status and estradiol treatment on nuclear receptor status, proliferation, organization, and inflammation within lesions were examined. αERKO lesions in WT hosts did not form distal to the incision site, respond to estradiol, or proliferate but did have increased inflammation. WT lesions in αERKO hosts did respond to estradiol, proliferate, and show decreased inflammation with treatment, but surprisingly, progesterone receptor expression and localization remained unchanged. Only minor differences were observed between WT lesions in βERKO hosts and βERKO lesions in WT hosts, demonstrating the estradiol-mediated signaling responses are predominately through ERα. In sum, these results suggest ER in both endometriosis-like lesions and their environment influence lesion characteristics, and understanding these interactions may play a critical role in elucidating this enigmatic disease.

Imbalance in cytokines from interleukin-1 family - role in pathogenesis of endometriosis

PROBLEM

To assess whether interleukin (IL)-1beta, IL-18 and interleukin-1 converting enzyme (ICE) are involved in the pathogenesis of endometriosis.

METHOD OF STUDY

Peritoneal fluid (PF) was obtained from 85 women with and without endometriosis. Peritoneal macrophages were cultured and the culture media collected. IL-1beta, IL-18 and ICE levels were measured by the enzyme-linked immunosorbent assay (ELISA).

RESULTS

Levels of IL-1beta and ICE in PF of women with endometriosis were higher than those in the control group. However, PF level of IL-18 was significantly lower in the study group than in the controls. Higher secretion of IL-1beta by peritoneal macrophages and lower IL-18 and ICE in endometriosis patients than in control were observed. Following lipopolysaccharide (LPS) stimulation, the macrophages secreted more IL-1beta, IL-18 and ICE in all groups.

CONCLUSIONS

The results pointed to impairment of the secretion of the IL-1 cytokine family in endometriosis. Invalid IL-1beta and IL-18 maturation by ICE may be an important pathogenic factor in endometriosis.

Chitotriosidase levels in patients with severe endometriosis

OBJECTIVE

To study the levels of chitotriosidase activity in the peritoneal fluid and the plasma of patients with severe endometriosis and control subjects.

MATERIALS AND METHODS

Twenty-five women with laparoscopically and histopathologically confirmed endometriosis (study group) and 27 control patients who had undergone laparoscopic surgery were included. Peritoneal fluid and peripheral blood were obtained from all the patients before the surgery. Chitotriosidase activities were measured.

RESULTS

Analysis of chitotriosidase activity in the peritoneal fluid of patients with endometriosis showed that there was no significant difference between endometriosis and control group, respectively (32.04 ± 64.20 vs. 15.25 ± 31.17 nmol/mL/h; p > 0.05). Analysis of chitotriosidase activity in plasma of patients with endometriosis showed significantly increased levels of chitotriosidase levels compared with the control group (74.81 ± 60.54 vs. 14.10 ± 26.17; p < 0.001), respectively.

CONCLUSION

We found that the activity of chitotriosidase in plasma was statistically higher in severe endometriosis patients than women without endometriosis.

Lipoxin A4 inhibits the development of endometriosis in mice: the role of anti-inflammation and anti-angiogenesis

PROBLEM

To evaluate the effects of the anti-inflammatory and anti-angiogenic roles of LXA4 on endometriosis in mice.

METHOD OF STUDY

Endometriosis was induced in 40 mice and separated into two groups. LXA4 group was administered by LXA4 for 3 weeks. The endometriotic lesions were counted, measured, and identified by pathology. The presence of a panel of pro-inflammatory factors was assessed by real-time RT-PCR, and enzyme-linked immunoassay, the mRNA, protein levels of matrix metalloproteinase (MMPs), and vascular endothelial growth factor (VEGF) were determined by real-time RT-PCR and immunohistochemistry; the activity of MMPs was evaluated by gelatin zymography.

RESULTS

Treatment with LXA4 significantly inhibited endometriotic lesion development (13.58 ± 4.01 mm(2) in LXA4 group and 23.20 ± 7.49 mm(2) , P = 0.0002), downregulated pro-inflammatory factors, suppressed the activity of MMP9, and reduced the VEGF levels associated with endometriosis in mice.

CONCLUSION

LXA4 may inhibit the progression of endometriosis possibly by anti-inflammation and anti-angiogenesis.

Accumulative copy number increase of MET drives tumor development and histological progression in a subset of ovarian clear-cell adenocarcinomas

Our previous study demonstrated that, among ovarian carcinomas, amplification of the MET gene and overexpression of MET specifically and commonly occur in clear-cell adenocarcinoma histology. This study was conducted to address how these alterations contribute to development and progression of this highly chemoresistant form of ovarian cancer. We histologically reviewed 21 previously described MET amplification-positive clear-cell adenocarcinoma cases, and selected 11 tumors with synchronous endometriosis and 2 tumors with adjacent clear-cell adenofibroma (CCAF) components. Using double in situ hybridization and immunohistochemistry, copy number alterations of the MET gene and levels of MET protein expression were analyzed in these putative precursor lesions and the corresponding invasive carcinoma components in this selected cohort. All of the non-atypical precursor lesions analyzed (ie, non-atypical endometrioses and the benign CCAFs) were negative for MET gain. However, low-level (≥3 MET copies in ≥10% and ≥4 MET copies in 10-40% of tumor cells) gain of MET was detected in 4 (40%) of the 10 atypical endometrioses and 1 of the 2 borderline CCAFs. Moreover, high-level (≥4 MET copies in ≥40% of tumor cells) gain of MET were detected in five (50%) of the atypical endometrioses. In 4 (31%) of the 13 cases enrolled, intratumoral heterogeneity for MET gain was documented in invasive carcinoma components, wherein all the relatively differentiated carcinoma components showed low-level gain of MET and all the corresponding poorly differentiated carcinomas showed high-level gain. The overall incidence of MET overexpression gradually increased from the precursors of non-atypical form (0%), through those of atypical form (67%) and the relatively differentiated carcinoma components (92%), to the poorly differentiated carcinoma components (100%). These results suggest that accumulative MET gene copy number alterations causing MET overexpression are associated with higher tumor grade and might drive the development and progression of the MET amplification-positive ovarian clear-cell adenocarcinoma.

Endometriosis, angiogenesis and tissue factor

Tissue factor (TF), is a cellular receptor that binds the factor VII/VIIa to initiate the blood coagulation cascade. In addition to its role as the initiator of the hemostatic cascade, TF is known to be involved in angiogenesis via intracellular signaling that utilizes the protease activated receptor-2 (PAR-2). We now review the physiologic expression of TF in the endometrium and its altered expression in multiple cell types derived from eutopic and ectopic endometrium from women with endometriosis compared with normal endometrium. Our findings suggest that TF might be an ideal target for therapeutic intervention in endometriosis. We have employed a novel immunoconjugate molecule known as Icon and were able to eradicate endometrial lesions in a mouse model of endometriosis without affecting fertility. These findings have major implications for potential treatment in humans.

Endometriosis and ovarian cancer: a review of clinical, pathologic, and molecular aspects

Endometriosis is a chronic disease that affects millions of reproductive-age women. Despite the destructive and invasive nature of endometrioses, most cases are perpetually benign or eventually regress; however, atypical endometriosis is a precursor lesion and can lead to certain types of ovarian cancer. Endometriosis induced inflammation and auto- and paracrine production of sex steroid hormones contribute to ovarian tumorigenesis. These changes provide microenvironment necessary to accumulate enough genetic alterations for endometriosis associated malignant transformation. It takes years for endometriosis to undergo the pathophysiological progression that begins with atypical epithelial proliferation (atypical endometriosis and metaplasia), and then is followed by the formation of well-defined borderline tumors, and finally culminates in fully malignant ovarian cancer. This study is a review of the natural history of endometriosis and the role of microenvironments that favor the accumulation of genetic alterations and endometriosis-associated ovarian cancer progression.

Effectiveness of the association micronized N-Palmitoylethanolamine (PEA)-transpolydatin in the treatment of chronic pelvic pain related to endometriosis after laparoscopic assessment: a pilot study

OBJECTIVE

Aim of our study was to evaluate the effectiveness of the association between N-Palmitoylethanolamine and transpolydatin in the management of chronic pelvic pain related to EMS.

STUDY DESIGN

This was a randomized, double-blind, parallel-group, placebo-controlled clinical trial involving 61 subjects, submitted to a first line laparoscopic conservative surgery, who were randomized into 3 groups receiving: group A (n=21) the association N-Palmitoylethanolamine-transpolydatin 400 mg + 40 mg twice a day for 3 months; group B (n=20) the placebo for 3 months; group C (n=20) a single course of Celecoxib 200mg twice a day for 7 consecutive days. Assessments of the severity of pelvic endometriosis (pelvic pain, dysmenorrhoea and dyspareunia) were recorded before and after treatment on a questionnaire and a 10-point VAS. Differences between groups were verified with Kruskal-Wallis ANOVA for non-parametric multiple comparisons.

RESULTS

A marked decrease in dysmenorrhoea, dyspareunia and pelvic pain was observed in all groups, and the association between N-Palmitoylethanolamine and transpolydatin resulted to be more effective than placebo (P<.001). Additionally, the treatment with Celecoxib resulted in a decrease in pelvic pain more effective either than the association N-Palmitoylethanolamine and transpolydatin or placebo.

CONCLUSION

These preliminary results show that the association between micronized N-Palmitoylethanolamine and transpolydatin is effective in the management of pelvic pain related to endometriosis after laparoscopy. Additionally, this association seems to be safe, shows an optimal control of pain and can be used in patients who are unable to receive other therapies.

New insights into the pathophysiology of endometriosis: from chronic inflammation to danger signal

BACKGROUND

Various theories try to explain the development and progression of endometriosis, however, no single theory can explain all aspects of this disorder. Gene expression profiling studies might reveal factors that explain variability in disease development and progression, which can serve as specific biomarkers for endometriosis and novel drug development. We have recently showed that the upregulated genes were predominantly clustered in stress and detoxification, providing a mechanistic explanation for the oxidative stress and chronic inflammatory response in endometriosis.

OBJECTIVE

This review aims: (1) to analyse the published data, with the aim of identifying pathways consistently regulated by the endometriosis genotype and (2) to summarise the findings of specific genes, which are involved in the process of oxidative stress and inflammation.

METHODS

We identified gene array and proteomics studies whose data were accessible in PubMed.

RESULTS

A major finding is the increased expressions of several markers including heat shock protein, S100, fibronectin, and neutrophil elastase, which might be involved in the process of Toll-like receptor (TLR)-dependent sterile inflammation. The study reviews a convergence in the main pathogenic process, where the TLR-mediated inflammation occurs possibly through the endogenous ligands.

CONCLUSIONS

In conclusion, a circulus vitiosus of both the oxidative stress pathway and the TLR pathways is generated when the process becomes chronic (danger signal spiral).

Reciprocal communication between endometrial stromal cells and macrophages

This study tested the hypothesis that reciprocal communication occurs between macrophages and cultured human endometrial stromal cells and that this communication may contribute to the pathology of endometriosis. An endometrial stromal cell line (telomerase-immortalized human endometrial stromal cell [T-HESC]) was treated with macrophage-conditioned medium (CM) +/- estradiol + progesterone. Macrophages were treated without or with T-HESC CM. DNA microarray identified 716 differentially expressed genes in T-HESCs in response to factors secreted by macrophages. Upregulated genes in T-HESC included interleukin 8 (IL-8)/chemokine (C-X-C motif) ligand 8 (CXCL8), matrix metalloproteinase 3 (MMP3), phospholamban, cysteine-rich angiogenic inducer 61 (CYR61), connective tissue growth factor (CTGF), tenascin C, and nicotinamide N-methyltransferase (NNMT), whereas integrin alpha-6 was downregulated. In contrast, 15 named genes were differentially expressed in macrophages in response to factors secreted by endometrial stromal cells. The data document reciprocal communication between macrophages and endometrial stromal cells and suggest that interaction with macrophages stimulates the expression of genes in endometrial stromal cells that may support the establishment of endometriosis.

Plasma C3a-des-Arg levels in women with and without endometriosis

PROBLEM

The lack of a reliable method for early non-invasive detection of endometriosis often results in delayed diagnosis. The aim of this study was to test the hypothesis that the plasma concentration of complement factor C3a (anaphylatoxin) can be used as a non-invasive test in the diagnosis of endometriosis.

METHOD OF STUDY

The C3a concentration was analyzed using ELISA in 160 patients with (n = 109) or without (n = 51) endometriosis during menstruation (n = 49), follicular phase (n = 55), and luteal (n = 56) phase.

RESULTS

Plasma C3a concentration was comparable between patients with [102 (27-2213) ng/mL] and without [105 (32-2340) ng/mL] (P = 0.84) endometriosis, also when assessed separately during menstruation, follicular phase, and luteal phase.

CONCLUSION

We found no difference in C3a levels between women with and without endometriosis and did not confirm our hypothesis that plasma C3a levels can be used as diagnostic test for endometriosis.