Role of cytokines in progression of endometriosis

A long-acting anti-IL-8 antibody improves inflammation and fibrosis in endometriosis

Current pharmacological treatments for endometriosis are limited to hormonal agents that can relieve pain but cannot cure the disease. Therefore, the development of a disease-modifying drug for endometriosis is an unmet medical need. By studying human endometriotic samples, we found that the progression of endometriosis was associated with the development of inflammation and fibrosis. In addition, IL-8 expression was highly up-regulated in endometriotic tissues and closely correlated with disease progression. We created a long-acting recycling antibody against IL-8 (AMY109) and evaluated its clinical potency. Because rodents do not produce IL-8 and do not experience menstruation, we analyzed the lesions in cynomolgus monkeys that spontaneously developed endometriosis and in a surgically induced endometriosis monkey model. Both spontaneously developed and surgically induced endometriotic lesions demonstrated pathophysiology that was highly similar to that of human endometriosis. Once-a-month subcutaneous injection of AMY109 to monkeys with surgically induced endometriosis reduced the volume of nodular lesions, lowered the Revised American Society for Reproductive Medicine score as modified for monkeys, and ameliorated fibrosis and adhesions. In addition, experiments using cells derived from human endometriosis revealed that AMY109 inhibited the recruitment of neutrophils to endometriotic lesions and the production of monocyte chemoattractant protein-1 from neutrophils. Thus, AMY109 may represent a disease-modifying therapy for patients with endometriosis.

Serum leucine-rich α2-glycoprotein as a possible marker for inflammatory status in endometriosis

Purpose

This study aimed to investigate whether serum leucine-rich α2-glycoprotein (LRG) is a useful diagnostic biomarker for endometriosis, including the evaluation of treatment efficacy and exploration of LRG production in endometriotic lesions.

Methods

Forty-three women with endometriomas were compared to 22 women with benign ovarian cysts and 30 women who underwent assisted reproduction as controls. Changes in serum LRG levels were assessed before and after surgery, and during dienogest treatment. LRG expression in endometriotic tissue samples was evaluated using immunoblotting.

Results

Serum LRG levels in the endometrioma group (80.0 ± 36.3 μg/mL) were significantly higher than those in the benign ovarian cyst (65.1 ± 27.0 μg/mL, p = 0.0265) and control (57.8 ± 22.3 μg/mL, p = 0.0028) groups. Serum LRG levels after endometrioma surgery were significantly lower than preoperative levels (p = 0.0484). Serum LRG levels consistently decreased during dienogest treatment. LRG expression levels were significantly higher in endometriotic tissues than in the normal endometrium.

Conclusion

Serum LRG, possibly derived from local and systemic origins, could be used as a potential biomarker for the diagnosis and treatment of endometriosis.

Adipose tissue-derived mesenchymal stem cells reduce endometriosis cellular proliferation through their anti-inflammatory effects

Objective

Endometriosis is a chronic debilitating inflammatory condition characterized by the presence of endometrial tissues outside the uterine cavity. Pelvic soreness and infertility are the usual association. Due to the poor effectiveness of the hormone therapy and the high incidence of recurrence following surgical excision, there is no single effective option for management of endometriosis. Mesenchymal stem cells (MSCs) are multipotent stromal cells studied for their broad immunoregulatory and anti-inflammatory properties; however, their efficiency in endometriosis cases is still a controversial issue. Our study aim was to evaluate whether adipose tissue-derived MSCs (AD-MSCs) could help with endometriosis through their studied anti-inflammatory role.

Methods

Female Wistar rats weighting 180 to 250 g were randomly divided into two groups: group 1, endometriosis group; established by transplanting autologous uterine tissue into rats’ peritoneal cavities and group 2, stem cell treated group; treated with AD-MSCs on the 5th day after induction of endometriosis. The proliferative activity of the endometriosis lesions was evaluated through Ki67 staining. Quantitative estimation of interferon γ, tumor necrosis factor-α, interleukin (IL)-6, IL-1β, IL-10, and transforming growth factor β expression, as well as immunohistochemical detection of CD68 positive macrophages, were used to assess the inflammatory status.

Results

The size and proliferative activity of endometriosis lesions were significantly reduced in the stem cell treated group. Stem cells efficiently mitigated endometriosis associated chronic inflammatory reactions estimated through reduction of CD68 positive macrophages and the expression of the proinflammatory cytokines.

Conclusion

Stem cell therapy can be considered a novel remedy in endometriosis possibly through its anti-inflammatory and antiproliferative properties.

Effects of bone marrow mesenchymal stem cell transplantation on tumor necrosis factor-alpha receptor 1 expression, granulosa cell apoptosis, and folliculogenesis repair in endometriosis mouse models

BACKGROUND AND AIM

Endometriosis affects the ovaries and causes a decrease in the oocyte quality during endometrial receptivity. During the development of ovarian follicles, paracrine communication occurs between granulosa cells and oocytes. This study was conducted to determine the effects of bone marrow mesenchymal stem cell transplantation on tumor necrosis factor-alpha (TNF-α) receptor 1 (TNFR1) expression, granulosa cell apoptosis, and folliculogenesis in endometriosis mouse models.

MATERIALS AND METHODS

This study involved 42 female mice, which were divided into three groups: Healthy mice (T0), endometriosis mice without transplantation (T1), and endometriosis mice with bone marrow mesenchymal stem cell transplantation (T2). The mice were injected intraperitoneally with endometrial fragments (200 μL) to become endometriosis models. On day 15, the endometriosis models received mesenchymal stem cells. Sample collection was performed on day 29. Granulosa cell apoptosis and TNFR1 expression were examined using immunohistochemical staining, and folliculogenesis was assessed using hematoxylin and eosin staining of ovary samples. The data obtained from both examinations were statistically analyzed using Statistical Package for the Social Sciences.

RESULTS

The results showed that TNFR1 expression is significantly decreased in T2 (p<0.004). The apoptosis of granulosa cells was lower in T2 (p<0.000). The primary, secondary, and graafian follicle counts in T2 were significantly increased.

CONCLUSION

Bone marrow mesenchymal stem cell transplantation in endometriosis mouse models can reduce TNFR1 expression and granulosa cell apoptosis and improve folliculogenesis.

Expression of monocyte chemotactic protein 2 and tumor necrosis factor alpha in human normal endometrium and endometriotic tissues

Endometriosis is a gynocological disease characterized by the presence of the endometrial glands and stroma outside the uterine cavity. This disease affects % 6-10 of women with reproductive age and it causes serious problems such as pelvic pain, dysmenorrhea and infertility. Although endometriosis is one of the most investigated disease of gynecology, its pathogenesis is not clear completely. In recent years, many studies revealed the inflammatory nature of endometriosis. Many of the immune cells and their secretory products cytokines and chemokines has been detected in body fluids of women with endometriosis. Cytokines are protein or glycoprotein in structures and hormon-like molecules that act generally in a paracrine fashion to regulate immun responses. They involved in chemotaxis, cell proliferation, cell activation, motility, adhesion and morphogenesis. Tumor necrosis factor alpha (TNF-α) is a proinflammatory cytokine secreted by the macrophages, monocytes, neutrophiles, T cells and natural killer cells. It stimulates increase in the level of the chemokines in body fluids. Monocyte chemotactic protein 2 (MCP-2) is a chemokine act to recruit and activate monocytes into sites of inflammation area. The aim of this study to investigate the ultrastructural properties and whether the expression and localization of TNF-α and MCP-2 in the eutopic endometrium (normal endometrium of women with endometriosis) and endometritic tissues of women with endometriosis. Eutopic endometrial and endometriotic tissue samples were obtained from women with endometriosis between 20-41 y and normal endometrial tissues were collected from 5 women without endometriosis as a control group. Tissues were processed for light and electron microscopy and examined. The epithelial cells of endometriotic tissues were revealed strongly cytoplasmic TNF-α and MCP-2 immunreactivities. Eutopic endometrial tissues were also stained prominently for both TNF-α and MCP-2. Furthermore, a significant increase in stromal macrophages were observed in endometriotic tissues. Moreover, the ultrastructural observations on the normal and endometriotic tissues were exhibited microvilli-rich cells and ciliated cells. These findings suggest that TNF-α and MCP-2 may be involved in normal endometrial biology and in the pathogenesis of endometriosis.

Icon immunoconjugate treatment results in regression of red lesions in a non-human primate (Papio anubis) model of endometriosis

Endometriosis is a common condition in reproductive-aged women characterized by ectopic endometrial lesions of varied appearance, including red, white, blue, black or powder burn coloration, which contribute to chronic pain and infertility. The immunoconjugate molecule (Icon) targets Tissue Factor, a transmembrane receptor for Factor VII/VIIa that is aberrantly expressed in the endothelium supporting ectopic endometrial tissue. Icon has been shown to cause regression of endometriosis in a murine model of disease but prior to this study had not been tested in non-human primates. This study evaluated Icon as a novel treatment for endometriosis in non-human primates (Papio anubis) using an adenoviral vector (AdIcon) delivery system. Female baboons (n = 15) underwent surgical induction of endometriosis. After laparoscopic confirmation of endometriosis lesions 6-weeks post-surgery, the treatment group (n = 7) received weekly intraperitoneal injections of viral particles carrying the sequence for Icon, resulting in expression of the protein, while the control group (n = 8) received no treatment. Icon preferentially reduced the number and volume of red vascularized lesions. Icon may present a novel treatment for endometriosis by degrading red vascularized lesions, likely by targeting tissue factor aberrantly expressed in the lesion vasculature.

Pain Symptoms and Peritoneal Fluid Cytokine and Marker Concentrations in Women with and without Endometriosis

Purpose

Endometriosis is not only associated with infertility, it is also a common cause of pain in women, leading to work absenteeism and a reduced quality of life. The objective of this study was to confirm the increased peritoneal fluid (PF) concentration of several cytokines in endometriosis patients, to investigate their association with pain levels, and to identify new biological markers in the PF which are neurostimulatory and thus responsible for the appearance and severity of different types of pain.

Methods

Our sample group included 111 patients with histologically confirmed endometriosis and 47 controls undergoing laparoscopy for reasons of abdominal pain or infertility. They rated their pain during menstruation, during sexual intercourse and general lower abdominal pain prior to undergoing surgery in our clinic using a visual analogue scale. During laparoscopy, PF was aspirated. Marker cytokine concentrations were measured by immunoassay and correlated to the Revised American Fertility Society (rAFS) stage of endometriosis and to the pain level using non-parametric methods.

Results

Differences were found between the correlations of the peritoneal fluid levels of many cytokines with dysmenorrhea or lower abdominal pain, and with the presence of severe endometriosis (rAFS III+IV). Glycodelin and osteoprotegerin (OPG) show the strongest associations with menstrual pain, while IL-8, MCP-1 and OPG were correlated to the stage of endometriosis. Low density cytokine protein arrays did not contribute to finding new markers for endometriosis and pain.

Conclusions

These findings illustrate the large variation of cytokine levels between patients. Glycodelin, IL-8 and OPG are the most likely targets for further investigations towards their future clinical use.

Resolvins RvD1 and 17(R)-RvD1 alleviate signs of inflammation in a rat model of endometriosis

OBJECTIVE

To study the effects of two resolvins of D series, RvD1 and 17(R)-RvD1, on inflammatory signs associated with endometriosis (ENDO).

DESIGN

In vivo research study.

SETTING

Research laboratory.

ANIMAL(S)

Female Sprague-Dawley rats.

INTERVENTION(S)

Intravenous or intraperitoneal injections of RvD1 (300 ng/kg) or 17(R)-RvD1 (300 and 900 ng/kg) in rats with surgically induced ENDO.

MAIN OUTCOME MEASURE(S)

Vascular permeability of ectopic endometrial growths was assessed by Evans Blue extravasation; vaginal hyperalgesia was assessed with telemetered visceromotor response.

RESULT(S)

Both resolvins, but not vehicle, significantly decreased vascular permeability in ectopic endometrial tissue. 17(R)-RvD1 also significantly alleviated severity of vaginal hyperalgesia.

CONCLUSION(S)

Our results suggest that RvD1 and 17(R)-RvD1 can be considered for further investigation of their therapeutic potential for treating ENDO.

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.

Suppression of COUP-TFII by proinflammatory cytokines contributes to the pathogenesis of endometriosis

CONTEXT

Endometriosis is one of the most common gynecological diseases in women with a prevalence rate of approximately 10%. Chronic pelvic inflammation has been observed in patients with endometriosis and is associated with disease severity. However, how pelvic inflammation promotes endometriosis progression remains unknown.

OBJECTIVE

The objective of the study was to investigate the regulatory network of proinflammatory cytokines in endometriosis progression.

DESIGN, SETTINGS, AND PATIENTS

Immunostaining of human endometrial (n = 21) and endometriotic (n = 36) sections, quantitative RT-PCR, Western blotting, chromatin immunoprecipitation, and luciferase reporter assays in primary culture human endometrial stromal cells were performed. Autologous transplantation of uterine endometrium from control chicken ovalbumin upstream promoter-transcription factor II [(COUP-TFII) flox/flox] and uterus-specific COUP-TFII knockout mice was performed.

RESULTS

Expression of COUP-TFII was significantly reduced in endometriotic stroma. Reduction of COUP-TFII in endometriotic stromal cells was mediated by proinflammatory cytokines including IL-1β, TNF-α, and TGF-β1 via a common effector, microRNA-302a. Treatment with these proinflammatory cytokines increased the expression of microRNA-302a, which targets the 3'untranslated region of COUP-TFII to cause its down-regulation. Intriguingly, down-regulation of COUP-TFII in endometrial stromal cells resulted in de-repression of cyclooxygenase-2 (COX-2). Further investigation demonstrated that COUP-TFII directly binds to COX-2 promoter to inhibit its transcription. Forced expression of COUP-TFII inhibited IL-1β-induced COX-2 up-regulation, whereas the knockdown of COUP-TFII augmented this effect.

CONCLUSION

Because overexpression of COX-2 has been demonstrated to be a master regulator in endometriosis progression, our data demonstrate the critical function of proinflammatory cytokines and the COUP-TFII regulatory gene network in the progression of endometriosis.

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.

Induction of the neurokinin 1 receptor by TNFα in endometriotic tissue provides the potential for neurogenic control over endometriotic lesion growth

CONTEXT

Endometriosis is characterized by the growth of ectopic endometrial tissue. Nerve fibers are frequently associated with ectopic lesions, and neurogenic inflammation may play a role in endometriosis.

OBJECTIVE

The purpose of this study was to determine the presence of tachykinin receptors in endometriotic lesions and the role of TNFα on their expression.

DESIGN

This study was an assessment of matching eutopic and ectopic endometrial tissue and peritoneal fluid from patients with endometriosis and an in vitro analysis of primary endometrial cells.

SETTING

The setting was a university hospital.

PATIENTS

Participants were premenopausal women undergoing laparoscopy.

INTERVENTIONS

Endometriotic lesions were removed surgically.

MAIN OUTCOME MEASURES

Tachykinin mRNA (TACR1/2) and protein (neurokinin 1 receptor [NK1R]) expression in both eutopic and ectopic endometrial tissue from patients with endometriosis and the correlation to peritoneal fluid TNFα were measured. Primary endometrial epithelial and stromal cells were assessed in vitro to determine the induction of TACR1/2 and NK1R expression after TNFα treatment. Cell viability of endometrial stromal cells after substance P exposure was also assessed.

RESULTS

Expression of both TACR1 and TACR2 mRNA was significantly higher in the ectopic than in the eutopic tissue. Both TACR1 mRNA and NK1R protein expression was significantly correlated with peritoneal fluid TNFα, and in vitro studies confirmed that TNFα treatment induced both TACR1 mRNA and NK1R protein expression in endometrial stromal cells. In endometrial stromal cells, substance P treatment enhanced cell viability, which was inhibited by a specific NK1R antagonist.

CONCLUSIONS

NK1R expression is induced in ectopic endometrial tissue by peritoneal TNFα. Induction of NK1R expression may permit endometriotic lesion maintenance via exposure to substance P.

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.

Analysis of cytokines in the peritoneal fluid of endometriosis patients as a function of the menstrual cycle stage using the Bio-Plex® platform

OBJECTIVE

Endometriosis is a painful disease affecting 10-15% of reproductive-age women. Concentrations of several cytokines and angiogenic factors in peritoneal fluid (PF) have been found to correlate with the severity of the disease. However, levels of some analytes vary across the menstrual cycle, and an ideal biomarker of endometriosis has not yet been identified. We have compared the PF concentrations of different cytokines in proliferative and secretory phases in women with and without the disease using the Bio-Plex platform.

METHODS

PF was aspirated during laparoscopy (N = 133) and the PF concentrations of 18 cytokines from Bio-Plex panels I and II determined with the serum protocol.

RESULTS

Increased PF concentrations of IL-6, IL-18, eotaxin, and MCP-1 were found in endometriosis with no changes with menstrual cycle. Levels of IL-12(p70), ICAM-1, and GRO-α were higher in the secretory phase, while eotaxin concentrations were lower.

CONCLUSION

Of the 18 cytokines tested, IL-6, IL-18 and MCP-1 were the best PF markers of endometriosis.

Lymphatic Vessels in Peritoneal Endometriotic Lesions

Purpose

While the exact pathogenesis of endometriosis remains unclear, it has been hypothesized that fragments of viable endometrial tissue shed at menstruation can transit via the lymphatic circulation and establish endometriotic lesions at distant sites. Mounting evidence suggests that related parameters such as immune cell densities are altered in peritoneal endometriotic lesions. However, lymphatic vessels in lesions have not been previously investigated. In this study, the presence and distribution of lymphatic micro-vessels were characterized in peritoneal endometriotic lesions and surrounding tissues.

Methods

Immunohistochemical staining was performed with an antibody specific for lymphatic endothelium (podoplanin, D2–40 clone) on 48 peritoneal endometriotic lesion specimens and 15 samples of normal surface peritoneum. Lymphatic micro-vessel density (LVD) was quantified in and around endometriotic lesions, and in normal surface peritoneum using an automated cellular imaging system.

Results

LVD in endometriotic stroma (mean ± SD = 31.1 ± 28.8 vessels per mm2) was significantly increased compared to both adjacent (8.8 ± 7.6, P<.001) and distant sub-peritoneum (17.7 ± 12.0, P=.002). In addition, lesion-adjacent LVD was significantly lower than distant (P<.001). No statistically significant differences in LVD were observed between endometriotic stroma and normal surface peritoneum from women without endometriosis (31.1 ± 26.5) or at different phases of the menstrual cycle.

Conclusions

This is the first report of LVD in peritoneal endometriotic lesions. LVD is increased in the stroma of peritoneal lesions compared to the surrounding sub-peritoneal tissue. Lymphatic micro-vessels play an important role in the trafficking of immune cells within endometriotic lesions and may be involved in lesion establishment.

Dose-response effect of interleukin (IL)-1β, tumour necrosis factor (TNF)-α, and interferon-γ on the in vitro production of epithelial neutrophil activating peptide-78 (ENA-78), IL-8, and IL-6 by human endometrial stromal cells

PURPOSE

The production of epithelial neutrophil activating peptide-78 (NA-78) and the interleukins IL-8 and IL-6 by endometrial stromal cells is stimulated by pro-inflammatory interleukin-1 (IL-1) and tumour necrosis factor-α (TNF-α). IL-8 is suggested to play a role in the pathogenesis of endometriosis, and in these women the peritoneal fluid concentrations of ENA-78 and IL-8 are increased. TNF-α has been tested together with interferon-γ because of their cooperative stimulation of IL-6. The release of IL-8, however, is inhibited with increasing interferon levels. The aim of the study was the analysis of the production of ENA-78, IL-6 and IL-8 by cultured human endometrial stromal cells in the presence of varying concentrations of IL-1β, TNF-α, and interferon-γ.

METHODS

Eutopic endometrial tissue was obtained from seven cycling, endometriosis-free women undergoing laparoscopy for reasons of infertility or pain. The release of ENA-78, IL-8 and IL-6 by the isolated and monolayer cultured stromal cell fraction in the presence of IL-1β (0.08 to 50 ng/mL), TNF-α, and interferon-γ (both 20 to 500 ng/mL) was determined.

RESULTS

IL-1β stimulated the production of IL-8, IL-6, and ENA-78 dose dependently from 0.08 to 2.0 ng/mL (ENA-78) or to 10 ng/mL (IL-8, IL-6); at 50 ng/mL a decrease in release was observed for IL-8 and IL-6. TNF-α stimulation yielded a plateau between 20 and 100 ng/mL. Interferon-γ stimulated IL-6 and inhibited IL-8 production above 20 ng/mL. ENA-78 release was largely unaffected by interferon-γ.

CONCLUSIONS

IL-1β and TNF-α stimulate stromal cytokine production cumulatively with different dose-response curves. The presence of interferon-γ has opposite effects on IL-8 and IL-6. TNF-α and interferon-γ should be investigated separately in future in vitro studies with endometrial cells and explants.

A long-acting tumor necrosis factor alpha-binding protein demonstrates activity in both in vitro and in vivo models of endometriosis

Endometriosis is characterized by the presence of elevated proinflammatory cytokines such as tumor necrosis factor (TNF) alpha in the peritoneal cavity. Blocking interaction of TNFalpha with its receptor by the addition of excess TNFalpha-binding protein (TBP)-1 (a soluble form of TNF receptor-1) was effective in animal models of endometriosis. Recently, a novel, high-affinity inhibitor of TNFalpha, TNF-soluble high-affinity receptor complex (TNF-SHARC), was created by fusing TBP to both the alpha and beta subunits of inactive human chorionic gonadotropin. This dimeric protein was effective in inhibiting collagen-induced arthritis in mice. In the present study, the efficacy of TNF-SHARC in cellular and in vivo models of endometriosis was examined. TBP and TNF-SHARC dose-dependently inhibited TNFalpha-induced secretion of interleukin (IL)-6, IL-8, granulocyte macrophage-colony-stimulating factor, and monocyte chemoattractant protein-1 in immortalized human endometriotic cells. An in vivo mouse model of experimentally induced endometriosis using cycling C57BL/6 mice was established. Antide treatment (0.5 mg/kg), used as positive control, initiated 7 days after the establishment of the disease, reduced the weight of the lesions compared with control. TNF-SHARC at 3 mg/kg was not effective in inhibiting the disease, whereas at 9 mg/kg there was reduction in the lesion weight. In addition, antide and TNF-SHARC treatment in vivo increased in vitro natural killer cell activity compared with untreated animals. Thus, we provide evidence for supporting the development of TNF-SHARC as a therapeutic candidate for treating endometriosis in human.

Correlation between symptoms of pain and peritoneal fluid inflammatory cytokine concentrations in endometriosis

Endometriosis affects 10-20% of women during reproductive age and is a common cause of infertility and pain leading to work absenteeism and reduced quality of life.The objective of this study was to investigate the association between the presence and concentration of interleukin-8 (IL-8), RANTES, osteoprotegerin (OPG), pregnancy-associated plasma protein A (PAPP-A), tumour necrosis factor-alpha (TNF-alpha), midkine and glycodelin in the peritoneal fluid (PF) and the intensity of pain reported by patients undergoing laparoscopy in our clinic. They rated their pain during menstruation, intercourse and lower abdominal using a visual analogue scale. During laparoscopy, PF was aspirated. Pain scores were correlated to the concentration of the above substances in the PF and to the stage of endometriosis. Endometriosis was histologically confirmed in 41 of 68 participating women; 27 without such evidence were considered as controls. TNF-alpha and glycodelin correlated positively with the level of menstrual pain. For IL-8, RANTES, OPG and PAPP-A no correlation between their PF concentration and the menstrual pain scores was observed. Patients with severe dysmenorrhoea had increased PF cytokine and marker levels; the difference was significant for TNF-alpha and glycodelin when compared with the other patients (no or moderate pain). TNF-alpha and glycodelin may thus play a role in endometriosis and the severity of menstrual pain.

The non-human primate model of endometriosis: research and implications for fecundity

The development of an animal model of endometriosis is crucial for the investigation of disease pathogenesis and therapeutic intervention. These models will enhance our ability to evaluate the causes for the subfertility associated with disease and provide a first-line validation of treatment modulators. Currently rodents and non-human primate models have been developed, but each model has their limitations. The aim of this manuscript is to summarize the current findings and theories on the development of endometriosis and disease progression and the effectiveness of therapeutic targets using the experimental induced model of endometriosis in the baboon (Papio anubis).

Human tumour necrosis factor: physiological and pathological roles in placenta and endometrium

The cytokine tumour necrosis factor alpha (TNF) is a well known member of the TNF superfamily consisting of at least 18 ligands and 29 different receptors involved in numerous cellular processes. TNF signals through two distinct receptors TNFR1 and TNFR2 thereby controlling expression of cytokines, immune receptors, proteases, growth factors and cell cycle genes which in turn regulate inflammation, survival, apoptosis, cell migration, proliferation and differentiation. Since expression of TNF was discovered in amnion and placenta many studies demonstrated the presence of the cytokine and its receptors in the diverse human reproductive tissues. Whereas TNF has been implicated in ovulation, corpus luteum formation and luteolysis, this review focuses on the functions of TNF in human placental, endometrial and decidual cell types of normal tissues and also discusses its role in endometrial and gestational diseases. Physiological levels of the cytokine could be important for balancing cell fusion and apoptotic shedding of villous trophoblasts and to limit trophoblast invasion into maternal decidua. Regulation of the TNF/TNFR system by steroid hormones also suggests a role in uterine function including menstrual cycle-dependent destruction and regeneration of endometrial tissue. Aberrant levels of TNF, however, are associated with diverse reproductive diseases such as amniotic infections, recurrent spontaneous abortions, preeclampsia, preterm labour or endometriosis. Hence, concentrations, receptor distribution and length of stimulation determine whether TNF has beneficial or adverse effects on female reproduction and pregnancy.

Intraperitoneal inflammation decreases endometriosis in a mouse model

BACKGROUND

The role of the immune system in the pathogenesis of endometriosis remains elusive. It has been shown that patients have an altered peritoneal environment with increased levels of inflammatory cytokines, activated macrophages and reduced clearance of retrogradely transported endometrial fragments. However, it is not known if this unique inflammatory situation is cause or consequence of endometriosis. This study investigates the impact of a pre-existing peritoneal inflammation on endometriosis establishment in a mouse model.

METHODS

Endometriosis was induced by intraperitoneal injection of enhanced green fluorescent protein (EGFP)-expressing endometrium in mice. In parallel, a peritonitis model was established via intraperitoneal injection of thioglycolate medium (TM). Finally, endometriosis was induced in the inflamed peritoneal cavity and lesion establishment as well as morphological and histological characteristics were analysed.

RESULTS

Induction of endometriosis in an inflamed peritoneal cavity resulted in fewer lesions and significantly lower sum of lesion surface area per mouse in the TM-treated group. Additionally, a higher amount of non-attached debris could be detected in the peritoneal cavity of TM-treated mice.

CONCLUSIONS

An intraperitoneal inflammation decreases endometriosis establishment in this mouse model. Thus, a pre-existing peritoneal inflammation might not be a factor favouring the development of endometriosis.

Serum interleukin-8 levels are elevated in patients with ovarian endometrioma

OBJECTIVE

To determine whether serum interleukin (IL)-8 concentration can be measured in patients with ovarian endometrioma and whether this measurement is a useful tool in diagnosing this disease.

DESIGN

A controlled clinical study and an in vitro study.

SETTING

Department of Obstetrics and Gynecology, Tottori University, Japan.

PATIENT(S)

Seventy patients with ovarian endometrioma and 21 patients with benign ovarian cyst.

INTERVENTION(S)

Laparoscopic surgery or laparotomy for ovarian endometriomas or benign ovarian cyst was performed. Preoperative blood samples were obtained. Endometriotic stromal cells obtained from nine patients with endometrioma were cultured.

MAIN OUTCOME MEASURE(S)

Interleukin-8 concentration in the serum or supernatant of the cell culture was measured with use of ELISA.

RESULT(S)

The serum concentration of IL-8 in patients with endometrioma was significantly higher than in patients with benign ovarian cyst. The serum IL-8 threshold (25 pg/mL) had a higher sensitivity (71.4%) for diagnosing ovarian endometrioma than did serum CA-125 level. The increased rates of IL-8 concentration in the culture supernatants after adding tumor necrosis factor alpha were significantly higher in patients whose serum IL-8 levels were >or=25 pg/mL than in those with levels <25 pg/mL.

CONCLUSION(S)

Measuring of serum IL-8 concentration may be a valuable tool in diagnosing endometriosis.

Peroxisome proliferator-activated receptor-gamma and retinoid X receptor agonists synergistically suppress proliferation of immortalized endometrial stromal cells

OBJECTIVE

To examine whether trichostatin A (TSA), a histone deacetylase inhibitor (HDACI), can induce up-regulation of peroxisome proliferator-activating receptor gamma (PPAR gamma) and to see whether LG100268, a retinoid X receptor (RXR) ligand, can inhibit proliferation of endometriotic cells alone or in synergy with ciglitazone, a PPAR gamma agonist.

DESIGN

One endometrial stromal cell line and two endometriotic cell lines used as a model system: Western blot analysis to determine whether TSA can up-regulate PPAR gamma expression, and MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) proliferation assay to see whether ciglitazone and LG100268 have any antiproliferative effects individually or jointly.

SETTING

Academic.

PATIENT(S)

None.

INTERVENTION(S)

Culture of immortalized endometrial and endometriotic cell lines with TSA, or ciglitazone or LG100268.

MAIN OUTCOME MEASURE(S)

PPAR gamma protein expression levels in cells treated with or without TSA, and number of viable cells treated with or without ciglitazone, LG100268, or both.

RESULT(S)

The TSA treatment resulted in up-regulation of PPAR gamma expression in all cell lines in a dose-dependent fashion. Both ciglitazone and LG100268 inhibited proliferation in a dose-dependent manner, and the antiproliferative effects appeared to be synergistic. In addition, endometriotic cells were more sensitive than endometrial stromal cells to LG100268 treatment.

CONCLUSION(S)

The up-regulation of PPAR gamma induced by TSA indicates that the action of HDACIs also includes the PPAR gamma signaling pathway, suggesting that the activation of PPAR gamma is a desirable way to contain endometriosis phenotypes. The higher sensitivity of endometriotic cells than their endometrial counterpart to LG100268 treatment suggests that the sensitivity differential could be exploited effectively to eradicate unwanted ectopic endometrial tissues while minimizing the collateral damage to the normal endometrial tissues.

L-carnitine supplementation reduces oocyte cytoskeleton damage and embryo apoptosis induced by incubation in peritoneal fluid from patients with endometriosis

OBJECTIVE

To investigate the protective effect of L-carnitine (LC) against deleterious substances present in the peritoneal fluid (PF) of patients with endometriosis, which may affect the oocyte cytoskeleton and embryogenesis.

DESIGN

Experimental study.

SETTING

Research embryology laboratory at an academic hospital.

PATIENT(S)

Frozen metaphase II mouse oocytes and embryos.

INTERVENTION(S)

One hundred metaphase II mouse oocytes were divided into five groups and incubated: PF from endometriosis patients; PF from endometriosis patients + LC; PF from tubal ligation patients (patient control); LC only; and human tubal fluid (HTF) alone. A total of 180 eight-cell mouse embryos were divided into: endometriosis only; tubal ligation only; endometriosis + LC; LC alone; and HTF alone.

MAIN OUTCOME MEASURE(S)

Protective effect of LC on oocytes and embryos.

RESULT(S)

Incubation of the oocytes and the embryos with PF from patients with endometriosis statistically significantly damaged the oocyte microtubules and chromosomes and increased embryo apoptosis compared with controls. Incubation with LC (0.6 mg/mL) statistically significantly improved microtubule and chromosome structure and decreased the level of embryo apoptosis.

CONCLUSION(S)

We propose the use of LC as a supplement in patients with endometriosis, a novel approach that may help improve in vitro fertilization outcome in these patients.

Trichostatin A, a histone deacetylase inhibitor, attenuates invasiveness and reactivates E-cadherin expression in immortalized endometriotic cells

The objective of this study is to determine whether trichostatin A (TSA) can suppress the invasiveness of 2 endometriotic cell lines known to be invasive and E-cadherin negative. The membrane invasion culture system was used to assess cell invasion using invasive and a noninvasive bladder cancer cell lines as positive and negative controls, respectively. The E-cadherin mRNA levels and protein expression were evaluated by real-time reverse transcriptase polymerase chain reaction and Western blot analysis, respectively. The authors found that TSA attenuates the invasiveness of 2 cell lines in the presence or absence of tumor necrosis factor alpha (TNFalpha) stimulation. In addition, TSA treatment reactivates E-cadherin gene and protein expression in these cell lines. These results, along with recent findings that TSA suppresses proliferation, interleukin-1 beta-induced cyclo-oxygenase 2 expression, and constitutive or TNFalpha-stimulated nuclear factor kappa B activation in endometrial and endometriotic cells, makes histone deacetylase inhibitors a promising class of compounds for novel and more effective medical treatment of endometriosis, especially given the mounting evidence that endometrios be an epigenetic disease.

Targeting mast cells in endometriosis with janus kinase 3 inhibitor, JANEX-1

Endometriosis (EMS) is a chronic inflammatory disease of multifactorial etiology characterized by implantation and growth of endometrial glands and stroma outside the uterine cavity. EMS is a significant public health issue as it affects 15-20% of women in their reproductive age. Clinical symptoms may include pelvic pain, dysmenorrhea, dyspareunia, pelvic/abdominal masses, and infertility. Symptomatic treatments such as surgical resection and/or hormonal suppression of ovarian function and analgesics are not as effective as desired. Consequently, there is an enormous unmet need to develop effective medical therapy capable of preventing the occurrence and recurrence of EMS without undesirable side-effects. EMS-associated intra-abdominal bleeding episodes, local inflammation, adhesions, and i.p. immunologic dysfunction leads to pelvic nociception and pelvic pain. Increasing evidence supports the involvement of allergic-type inflammation in EMS. Invasion of mast cells, degranulation, and proliferation of interstitial component are observed in endometriotic lesions. Presence of activated and degranulating mast cells within the nerve structures can contribute to the development of pain and hyperalgesia by direct effects on primary nociceptive neurons. Therefore, treatments targeting endometrial mast cells may prove effective in preventing or alleviating EMS-associated symptoms. The Janus kinase 3 (JAK3) is abundantly expressed in mast cells and is required for the full expression of high-affinity IgE receptor-mediated mast cell inflammatory sequelae. JANEX-1/WHI-P131 is a rationally designed novel JAK3 inhibitor with potent anti-inflammatory activity in several cellular and in vivo animal models of inflammation, including mouse models of peritonitis, colitis, cellulitis, sunburn, and airway inflammation with favorable toxicity and pharmacokinetic profile. We hypothesize that JAK3 inhibitors, especially JANEX-1, may prove useful to prevent or alleviate the symptoms of EMS.

Apoptosis pattern in human endometrium in women with pelvic endometriosis

OBJECTIVE

In the present study we aimed to describe apoptosis patterns in eutopic endometrium in women suffering from endometriosis in order to assess its value as a marker of early forms of endometriosis, and also to try to answer whether endometriosis is caused by changes within the eutopic endometrium or whether endometriotic lesions change the characteristics of eutopic endometrium.

STUDY DESIGN

The study was performed on 125 women treated in Division of Reproduction. In 52 patients peritoneal endometriosis was diagnosed (I(0)-23; II(0)-29). Seventy-three patients in whom no endometriotic foci could be found at laparoscopy were qualified as the control group. Endometrial biopsy 7-9 days after ovulation was taken for assessment of apoptosis (TUNEL) and routine histology.

RESULTS

Apoptosis indices in the eutopic endometrium of women with endometriosis were lower compared to women without endometriosis. In the endometrial glands apoptosis indices were 2.94+/-1.66 versus 5.23+/-2.06 (p<0.01) in the group of women with and without endometriosis, respectively. In the endometrial stroma apoptosis indices were estimated at 2.04+/-1.72 in women with endometriosis and 4.12+/-1.62 in the control group (p<0.01).

CONCLUSIONS

The observed changes could support the hypothesis of the different properties of eutopic endometrium in endometriotic women as a causing factor of peritoneal endometriosis.

Nuclear factor-kappab (NF-kappaB): an unsuspected major culprit in the pathogenesis of endometriosis that is still at large?

Endometriosis, defined as the ectopic presence of endometrial glandular and stromal cells outside the uterine cavity, is a common benign gynecological disorder with an enigmatic pathogenesis. Many genes and gene products have been reported to be altered in endometriosis, yet some of them may not be major culprits but merely unwitting accomplices or even innocent bystanders. Therefore, the identification and apprehension of major culprits in the pathogenesis of endometriosis are crucial to the understanding of the pathogenesis and would help to develop better therapeutics for endometriosis. Although so far NF-kappaB only has left few traces of incriminating fingerprints, several lines of investigation suggest that NF-kappaB, a pivotal pro-inflammatory transcription factor, could promote and maintain endometriosis. Various inflammatory agents, growth factors, and oxidative stress activate NF-kappaB. NF-kappaB proteins themselves and proteins regulated by them have been linked to cellular transformation, proliferation, apoptosis, angiogenesis, and invasion. Interestingly, all existing and nearly all investigational medications for endometriosis appear to act through suppression of NF-kappaB activation. In endometriotic cells, NF-kappaB appears to be constitutively activated, and suppression of NF-kappaB activity by NF-kappaB inhibitors or proteasome inhibitors suppresses proliferation in vitro. Viewing NF-kappaB as a major culprit, an autoregulatory loop model can be postulated, which is consistent with existing data and, more importantly, can explain several puzzling phenomena that are otherwise difficult to interpret based on prevailing theories. This view has immediate and important implications for novel ways to treat endometriosis. Further research is warranted to precisely delineate the roles of NF-kappaB in the pathogenesis of endometriosis and to indict and convict its aiders and abettors.

Pathogenic Consequences in Semen Quality of an Autoimmune Response against the Prostate Gland: From Animal Models to Human Disease

We have recently proposed an autoimmune etiology in approximately 35% of chronic nonbacterial prostatitis patients, the most frequent form of prostatitis observed, because they exhibit IFN-gamma-secreting lymphocytes specific to prostate Ags. Interestingly, this particular group of patients, but not the rest of chronic nonbacterial prostatitis patients, also presented striking abnormalities in their semen quality. In this work, we use an experimental animal model of autoimmune prostatitis on Wistar rats developed in our laboratory to investigate when, where, and how sperm cells from autoimmune prostatitis individuals are being damaged. As in patients, a marked reduction in sperm concentration, almost null sperm motility and viability, and an increased percentage of apoptotic spermatozoa were detected in samples from animals with the disease. Prostate-specific autoantibodies as well as elevated levels of NO, TNF-alpha, and IFN-gamma were also detected in their seminal plasma. In contrast, epididymal spermatozoa remain intact, indicating that sperm damage occurs at the moment of joining of prostate secretion to sperm cells during ejaculation. These results were further supported by experiments in which mixture of normal sperm cells with autoimmune seminal plasma were performed. We hypothesize that sperm damage in experimental autoimmune prostatitis can be the consequence of an inflammatory milieu, originally produced by an autoimmune response in the prostate; a diminished prostate functionality, evidenced by reduced levels of citric acid in semen or by both mechanisms simultaneously. Once more, we suggest that autoimmunity to prostate may have consequences on fertility.

Increased peritoneal and endometrial gene expression of biologically relevant cytokines and growth factors during the menstrual phase in women with endometriosis

OBJECTIVE

To examine differential messenger RNA (mRNA) expression of relevant cytokines, metalloproteases, growth and adhesion factors in endometrium and peritoneum from women with endometriosis when compared with women without the disease during menstrual and luteal phases of the cycle.

DESIGN

Patients with endometriosis were compared with control patients.

SETTING

University hospital.

PATIENT(S)

A total of 35 patients (20 patients during the luteal phase and 15 patients during the menstrual phase) were selected for this study on the basis of cycle phase and presence or absence of endometriosis.

INTERVENTION(S)

In this study, endometriosis was laparoscopically and histologically confirmed in 24 women with endometriosis of revised American Society for Reproductive Medicine (ASRM) stage I-II (n = 12) and revised ASRM stage III-IV (n = 12), and the presence of a normal pelvis was documented by laparoscopy in 11 control patients. The macroscopically normal peritoneum tissues were collected from lateral wall left or right, near the colon ascendens or descendens.

MAIN OUTCOME MEASURE(S)

The expression levels were determined as ratios between the target molecules and beta-actin as housekeeping gene.

RESULT(S)

In women with endometriosis, peritoneal mRNA levels of matrix metalloproteinase (MMP)-3, transforming growth factor-beta, interleukin (IL)-6, and intercellular adhesion molecule-1 and endometrial mRNA levels of MMP-3, tumor necrosis factor (TNF)-alpha, and IL-8 were significantly higher during the menstrual phase when compared with luteal phase. During the menstrual phase of the cycle, both endometrial expression of TNF-alpha, IL-8, and MMP-3 mRNA levels and peritoneal expression of transforming growth factor-beta, IL-6, and intercellular adhesion molecule-1 mRNA levels were significantly higher in women with endometriosis when compared with controls. Immunohistochemical staining confirmed the presence of TNF-alpha in peritoneum and endometrium in both women with endometriosis and controls.

CONCLUSION(S)

Increased endometrial and peritoneal cytokine mRNA expression during menstruation may contribute to a pelvic inflammatory microenvironment favoring the development of endometriosis.

Effect of peroxisome proliferator-activated receptor-gamma agonist rosiglitazone on the induction of endometriosis in an experimental rat model

OBJECTIVE

To assess the effect of the peroxisome proliferator-activated receptor (PPAR)-gamma agonist rosiglitazone on the induction of endometriosis in a rat model.

METHODS

Endometriosis was surgically induced in 28 rats by transplanting an autologous fragment of endometrial tissue onto the inner surface of the abdominal wall. Group I was assigned as control and no medication was administered. Starting 3 days before the operation and continuing for 4 weeks, 0.2 mg/kg/d rosiglitazone was administered to the study group orally. Four weeks later rats were killed and ectopic uterine tissues were evaluated morphologically and histologically. Scoring systems were used to evaluate preservation of epithelia.

RESULTS

Four rats in the study group and one rat in the control group died of complications related to surgery. There was a significant difference in post-treatment spherical volumes (64.00 mm3 [interquartile range (IQR): 354.42] vs 41.60 mm3 [IQR: 37.87], P = .018) and explant weights (77.97 mg [IQR: 431.27] vs 47.24 mg [IQR: 43.01], P = .005) between control and rosiglitazone-treated groups. The epithelia were found to be preserved significantly better in the control group when compared with the roziglitazone-treated group (2.00 [IQR:2.00] vs 0.00 [IQR:2.25], P = .014).

CONCLUSIONS

Rosiglitazone was found to affect the induction of endometriosis negatively in this experimental rat model and seemed to interfere with the growth and maintenance of the uterine explant.

A baboon model for endometriosis: implications for fertility

Endometriosis is one of the most common causes of chronic pelvic pain and infertility in women in the reproductive age group. Although the existence of this disease has been known for over 100 years our current knowledge of its pathogenesis and the pathophysiology of its related infertility remains unclear. Several reasons contribute to our lack of knowledge, the most critical being the difficulty in carrying out objective long-term studies in women. Thus, we and others have developed a model of this disease in the non-human primate, the baboon (Papio anubis). Intraperitoneal inoculation of autologous menstrual endometrium results in the development of endometriotic lesions with gross morphological characteristics similar to those seen in the human. Multiple factors have been implicated in endometriosis-associated infertility. We have described aberrant levels of factors involved in multiple pathways important in the establishment of pregnancy, in the endometrium of baboons induced with endometriosis. Specifically, we have observed dysregulation of proteins involved in invasion, angiogenesis, methylation, cell growth, immunomodulation, and steroid hormone action. These data suggest that, in an induced model of endometriosis in the baboon, an increased angiogenic capacity, decreased apoptotic potential, progesterone resistance, estrogen hyper-responsiveness, and an inability to respond appropriately to embryonic signals contribute to the reduced fecundity associated with this disease.

Experimental Intestinal Endometriosis Is Characterized by Increased Levels of Soluble TNFRSF1B and Downregulation of Tnfrsf1a and Tnfrsf1b Gene Expression1

Endometriosis is commonly associated with symptoms similar to those of gastrointestinal diseases, such as inflammatory bowel disease (IBD), leading to erroneous diagnosis and inappropriate management. The role of tumor necrosis factor alpha (TNF) in IBD is well established, but its role in endometriosis--also characterized by the activation of inflammatory mechanisms--is still under study. Furthermore, little is known about the involvement of TNF receptors. Intestinal endometriosis was surgically induced in female Sprague-Dawley rats (n = 10). Control rats (n = 10) received sutures with no implants. Samples of tissue and fluids were collected 60 days after surgery. Endometriotic implants were classified in grades, and the gastrointestinal tract was examined for damage. A significant increase was observed in protein levels of TNF and soluble TNFRSF1B in the peritoneal fluid of experimental rats compared to controls. Expression of Tnf mRNA was significantly increased both in peritoneal leukocytes and in intestinal segments associated with implants in experimental animals. Bioactivity of TNF in tissues was confirmed by overexpression of Icam1, Sele, Vegfa, Flt1 and Kdr. Gene expression of Tnfrsf1a and Tnfrsf1b was downregulated in colon and small intestine of experimental animals, possibly as a mechanism of protection against TNF cytotoxicity. Significant overexpression of genes encoding TNF receptor-associated factors that have been linked to activation of antiapoptotic pathways also was observed. Overexpression of TNF and target genes, underexpression of TNF-receptor genes, and increased shedding of TNFRSF1B in this animal model provide further evidence for involvement of the TNF system in the pathogenesis of endometriosis.

Peritoneal fluid cytokines and sICAM-1 in minimal endometriosis: search for discriminating factors between infertility and/or endometriosis

OBJECTIVE

To evaluate cytokine levels (IL-1beta, TNF-alpha, IL-6, IL-8), soluble intercellular adhesion molecule-1 (sICAM-1) and number of macrophages in peritoneal fluid (PF) of women with no minimal endometriosis and associated (or not) infertility in order to discriminate between infertility and/or endometriosis.

STUDY DESIGN

Cytokines and sICAM-1 were measured by using quantitative enzyme-linked immunosorbent assay (ELISA) while the macrophages were identified by May-Grunwald-Giemsa and non-specific esterase staining and presented as medians. The measurements were performed in 78 women belonging to four selected subgroups according to their endometriosis and/or infertility status. Statistical analysis was performed using Kruskal-Wallis non-parametric ANOVA test. Additionally, discriminant function analyses were performed.

RESULTS

We have found the most elevated macrophage numbers in the groups of women with endometriosis. IL-1beta did not present any statistically significant values differentiating the analysed subgroups. IL-6 (110.0 pg/ml) and TNF-alpha exhibited the highest concentrations (statistically significant) in a group of fertile women with endometriosis. IL-8 clearly differentiated between the subgroups with infertility and sICAM-1 was statistically significantly elevated in the subgroups of infertile women. In the forward discriminant analysis, when subdividing the studied population according to its infertility status (we considered macrophages, IL-8 and IL-6 in order of probability values), we have found striking probability value of 92% for the correct classification into an infertile population.

CONCLUSION

Out of the range of the analysed factors we have found only the sICAM-1 to be singled out between the standard discriminant analysis and the forward one. However, this important flagging molecule might be of considerable value for discrimination between different types of pathology at the level of immune effector function. The increased levels of TNF-alpha and IL-6 signified a group of fertile women with endometriosis; however only IL-6 presented a discriminating value in multifunctional analysis of examined subgroups. The analysed range of factors had a greater tendency to discriminate between infertility status rather than endometriosis.

The presence of endometrial cells in the peritoneal cavity enhances monocyte recruitment and induces inflammatory cytokines in mice: implications for endometriosis

OBJECTIVE

To determine the inflammatory response in the peritoneal cavity by the presence of endometrial cells and the role of the mesothelium.

DESIGN

In vivo study using mice.

SETTING

University research laboratory.

ANIMAL(S)

Female Swiss Webster mice, 8 to 10 weeks old.

INTERVENTION(S)

Homogenous mouse endometrial epithelial and stromal cells were injected intraperitoneally. Peritoneal lavage and mesothelium were collected 4 to 72 hours after the administration.

MAIN OUTCOME MEASURE(S)

We determined the number of peritoneal macrophages, and the production and gene expression of monocyte chemotactic protein-1 (MCP-1/JE), interleukin 1alpha (IL-1alpha), and interleukin 6 (IL-6).

RESULT(S)

The intraperitoneal administration of endometrial cells increased the number of peritoneal macrophages, production of MCP-l, IL-1alpha, and IL-6, and expression of mesothelial MCP-1/JE, IL-1alpha, and IL-6 genes in recipient mice.

CONCLUSION(S)

These results suggest that retrograde menstruation could account for the increased presence of inflammatory mediators in the peritoneal cavity of women with endometriosis. The mesothelium could play an active role in endometriosis in addition to providing an attachment stratum for the endometrial cells.

Tumor necrosis factor alpha secretion by peritoneal macrophages in patients with endometriosis

INTRODUCTION

As a cytotoxic product of activated monocytes, macrophages, and lymphocytes, tumor necrosis factor alpha (TNF-alpha)--together with other cytokines and growth factors--is an important component in the immune response of the human organism. In addition, TNF-alpha plays a central role in neoangiogenesis. Because of its cytotoxicity with regard to several tumor cells and its motility-hindering effect on human sperm, TNF-alpha is considered to be a significant pelvic mediator of female sterility.

OBJECTIVE

The goal of our study was to determine as to whether or not an increased TNF-alpha secretion by peritoneal macrophages (PM) can be measured in female patients with endometriosis compared with healthy subjects, and if TNF-alpha secretion can be correlated with the activity of endometriosis.

METHODS

During infertility work-up, 100 female patients underwent a diagnostic laparoscopy. In accordance with the rAFS classification as well as from the macroscopic aspect of the degree of activity of the endometriosis, the patients were divided as follows: an endometriosis-free control group with a completely normal pelvic status (n=35) and three groups with increasing stages of endometriosis (n=65). In the control group (Group 1), the TNF-alpha concentrations (median values with minimum / maximum) were 6.2 pg/ml (1.9/10.2), in Group 2 with rAFS stage I/II less active endometriosis 56.33 pg/ml (39.5/71.2), in Group 3 with rAFS stage I/II but highly active endometriosis 81.41 pg/ml (68.4/98.7), while in Group 4 with rAFS stage III/IV 200,15 pg/ml (182.6/226.8), respectively.

CONCLUSION

In conclusion, we were able to show that the TNF-alpha secretion of PM was significantly higher in patients with proven endometriosis compared to the control group. These results were found to be statistically significant and were in accordance with the histological findings. Thus, due to its immunomodulating potential, TNF-alpha may be a marker of both activity and stage of endometriosis.

Potential involvement of the immune system in the development of endometriosis

This article presents an overview of immunological factors and their role in the development of endometriosis, with emphasis on inflammatory cytokines, growth and adhesion factors. Although retrograde menstruation is a common phenomenon among women of reproductive age, not all women who have retrograde menstruation develop endometriosis. The development of endometriosis is hypothesised to be a complex process, which may be facilitated by several factors, including the quantity and quality of endometrial cells in peritoneal fluid (PF), increased inflammatory activity in PF, increased endometrial-peritoneal adhesion and angiogenesis, reduced immune surveillance and clearance of endometrial cells, and increased production of autoantibodies against endometrial cells. Potential biomarkers like cytokines and autoantibodies upregulated during development of endometriosis may be useful in the development of a non-surgical diagnostic tool. Although endometriosis can be treated using hormonal suppression, there is need for non-hormonal drugs, which can inhibit the development of endometriosis and alleviate pain or infertility without inhibition of ovulation. New molecules that modulate immune function in endometriosis should be the targets for future research.

Epithelial neutrophil-activating peptide 78 concentrations are elevated in the peritoneal fluid of women with endometriosis

OBJECTIVE

To investigate the presence of epithelial neutrophil-activating peptide 78 (ENA-78) in peritoneal fluid of women with and without endometriosis and to identify the cells that produce this inflammatory protein.

DESIGN

Case-control study.

SETTING

University hospital.

PATIENT(S)

Eighteen women with and 9 women without endometriosis.

MAIN OUTCOME MEASURE(S)

ENA-78 protein and mRNA levels were compared among women with and without endometriosis in samples of peritoneal fluid, samples of endometriotic lesions obtained by biopsy during laparoscopy, and peritoneal macrophages. Enzyme-linked immunosorbent assay, reverse transcription polymerase chain reaction, and in situ hybridization methods were used. Secretion of ENA-78 protein by interleukin-1beta-stimulated endometriotic stromal cells and in the media of lipopolysaccharide-stimulated peritoneal macrophages were compared to that in unstimulated cell cultures.

RESULT(S)

Peritoneal fluid concentrations of ENA-78 were significantly higher in affected women than in controls. Ectopic epithelial and stromal cells and peritoneal macrophages express ENA-78 messenger RNA. Interleukin-1beta stimulation of stromal cell cultures resulted in a 23-fold increase in ENA-78 concentration, and lipopolysaccharide stimulation of peritoneal macrophages increased concentrations by 8-fold.

CONCLUSION(S)

Levels of ENA-78 are elevated in the peritoneal fluid of women with endometriosis. Ectopic glandular cells, ectopic stromal cells, and peritoneal macrophages express this inflammatory chemokine. Epithelial neutrophil-activating peptide 78 may play an important role in the pathogenesis of endometriosis.

Presence of endometrial epithelial cells in the peritoneal cavity and the mesothelial inflammatory response

OBJECTIVE

To determine the contribution of endometrial cells in the development of endometriosis. Specifically the response of the mesothelium to endometrial cells in the production of monocyte chemotactic protein-1 (MCP-1), interleukin-6 (IL-6), and IL-8 was studied.

DESIGN

In vitro study.

SETTING

University Research Laboratory.

PATIENT(S)

None.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Cellular MCP-1, IL-6 secretion and MCP-1, and IL-6 and IL-8 messenger RNA expression were evaluated by ELISA and reverse transcription-polymerase chain reaction (RT-PCR) assay.

RESULT(S)

The mesothelial cells produced more MCP-1 and IL-6 than endometrial epithelial and stromal cells. Mesothelial cells cultured in the presence of endometrial epithelial cells produced even greater levels of MCP-1 and IL-6 than those cultured in the presence of stromal cells or cultured alone. The MCP-1, IL-6, and IL-8 mRNA expression also increased when mesothelial cells were co-cultured with endometrial epithelial cells.

CONCLUSION(S)

The results suggest that endometrial epithelial cells may be important in evoking the inflammatory reaction in the peritoneal cavity during retrograde menstruation and that mesothelial cells may play an important role in the chemotaxis of monocytes and in the inflammatory process during the development of endometriosis.

Differential expression of interleukins (IL)-13 and IL-15 in ectopic and eutopic endometrium of women with endometriosis and normal fertile women

PROBLEM

Interleukins (IL) 13 and 15 are key regulators of inflammatory and immune responses, processes that are central to endometriosis and associated abnormalities. The present study examined (1) whether ectopic endometrial tissue expresses IL-13 and IL-15 (2) if their expression differs compared with matched eutopic endometrium and control endometrium from normal fertile women, and (3) if peritoneal fluids (PF) content of these cytokines reflects the disease compared with PF from women with peritoneal adhesions unrelated to endometriosis and those without pelvic pathology.

METHODS

The expression of IL-13 and IL-15 mRNA and protein was determined using quantitative RT-PCR, ELISA and immunohistochemistry.

RESULTS

Ectopic endometrium expresses IL-13 and IL-15 mRNA and protein with elevated levels compared with eutopic and control endometrium, irrespective of the phases of the menstrual cycle, with predominance in IL-13 expression. Endometrial epithelial cells were found to be the primary site of IL-13 and IL-15 expression. The PF content of IL-13 and IL-15 show a trend toward higher concentrations in women with adhesion and endometriosis, respectively, compared with fertile control without pelvic pathology.

CONCLUSION

Interleukins 13 and 15 are expressed in ectopic endometrium and present in PF of women with endometriosis and their elevated expression in ectopic endometrium suggests that these cytokines play a key role in local inflammatory/immune responses that are critical in endometriosis-associated abnormalities.

Endometriosis is sustained by tumour necrosis factor-alpha

Endometriosis is a common gynaecological disorder causing pain, infertility, and emotional distress. Evidence presented here suggests that abnormal production of tumour necrosis factor-alpha (TNF-alpha) is required for the establishment and maintenance of endometriosis and also is responsible for the associated infertility through its effect on sperm motility and function and oocyte development. Infliximab, which blocks TNF-alpha function, could be used in the treatment of endometriosis to reverse the above effects.

Use of intraperitoneal interferon alpha-2b therapy after conservative surgery for endometriosis and postoperative medical treatment with depot gonadotropin-releasing hormone analog: a randomized clinical trial

OBJECTIVE

To evaluate the possible therapeutic effects of interferon alpha-2b left in the peritoneum after surgery, followed by or not followed by treatment with GnRH analogs.

DESIGN

A prospective, randomized clinical trial.

SETTING

University hospital.

PATIENT(S)

Fifty-two infertile patients with moderate or severe endometriosis.

INTERVENTION(S)

Laparotomic conservative surgery and either interferon alpha-2b or saline alone left in the pouch of Douglas followed by administration of either GnRH analogs depot or oral indomethacin with transvaginal echography and analysis of CA-125, immunoglobulins, and lymphocyte populations.

MAIN OUTCOME MEASURE(S)

Recurrence of endometriosis was considered clinically, echographically, and laparoscopically.

RESULT(S)

Recurrence of endometriosis in four cases without interferon (15.4%) versus 11 patients (42.3%) with interferon alpha-2b. Life table analysis showed significant differences between the groups with and without interferon 21 months after conservative surgery. There were no differences in the recurrence between the groups with or without GnRH analogs. Likewise, there were no significant changes in immunoglobulins and lymphocyte populations among patients with and without recurrence of endometriosis. The patients that received GnRH analogs depot showed a decrease in the number of CD16 and an increase of CD11b cells after treatment.

CONCLUSION(S)

The use of interferon alpha-2b within the peritoneal cavity after conservative surgery may be inappropriate because it increased later recurrence of endometriosis. The postoperative treatment with GnRH analogs did not significantly reduce the recurrence rate. Immunoglobulins and lymphocyte populations did not change in relation to the recurrence of endometriosis.

Polymorphisms for interleukin-4 (IL-4) -590 promoter, IL-4 intron3, and tumor necrosis factor alpha -308 promoter: non-association with endometriosis

Interleukin-4 (IL-4) is a cytokine with anti-inflammatory properties. Tumor necrosis factor alpha (TNF-alpha), a pluripotent proinflammatory cytokine, plays an important role in the process of numerous inflammatory and autoimmune diseases. We aimed to investigate whether gene polymorphisms for the IL-4 -590 promoter, IL-4 intron3 and TNFalpha -308 promoter could be used as markers of susceptibility in endometriosis. The subjects, 226 premenopausal Taiwan Chinese women with surgically diagnosed endometriosis and nonendometriosis, were divided into two groups: 1) endometriosis (n = 120) and 2) nonendometriosis (n = 106). Polymorphisms for the IL-4 -590 promoter, IL-4 intron3, and TNFalpha -308 G-to-A promoter were detected by polymerase chain reaction (PCR). Genotypes and allelic frequencies for these gene polymorphisms in both groups were compared. We observed no significant differences in genotype distribution and allele frequency of the IL-4 -590 promoter, IL-4 intron3, and TNFalpha gene polymorphism between both groups. The proportions of the -590*C homozygote/heterozygote/-590* T homozygote for the IL-4 promoter in both groups were 1.6/31.6/66.6% in group 1, and 5.8/33.0/61.2% in group 2. The proportions of the RP1 homozygote/heterozygote/RP2 homozygote for IL-4 intron3 in both groups were 62.5/34.1/2.5% (group 1), and 64.1/32.0/3.9% (group 2). The proportions of -308*A homozygote/heterozygote/-308*G homozygote for the TNFalpha promoter in both groups were 7.5/20.8/71.7% (group 1), and 7.5/17/75.5% (group 2). We concluded that there is no association between endometriosis and the IL-4 and TNFalpha gene polymorphisms. The IL-4 -590 promoter, IL-4 intron3, and TNFalpha -308 G-to-A polymorphisms are not useful markers for predicting susceptibility to endometriosis.

Effect of interleukin-8 (IL-8), anti-IL-8, and IL-12 on endometrial cell survival in combined endometrial gland and stromal cell cultures derived from women with and without endometriosis

OBJECTIVE

To study the affects of interleukin-8 (IL-8), anti-IL-8, and IL-12 on in vitro proliferation of endometrial cells.

DESIGN

An in vitro study.

SETTING

Department of Obstetrics and Gynecology, University of Aberdeen, UK.

PATIENT(S)

Women attending a fertility clinic.

INTERVENTION(S)

In vitro cell cultures using culture media supplemented with IL-8 (100 ng/mL, 200 ng/mL, and 500 ng/mL), IL-12 (1 ng/mL, 5 ng/mL, and 25 ng/mL), and anti-IL-8 (0.1 microg/mL, 1 microg/mL, 10 microg/mL).

MAIN OUTCOME MEASURE(S)

In vitro survival of dispersed endometrial cells (combined epithelial and glandular) at 5 and 9 days of culture.

RESULT(S)

There was a dose-dependent stimulatory effect of IL-8 on survival of cells. From women with and without endometriosis, IL-12 at 1 ng/mL significantly inhibited the survival of endometrial cells from women without endometriosis as compared with cells from women with endometriosis. At 1 microg/mL, anti-IL-8 significantly inhibited the survival of endometrial cells from women with endometriosis compared with cells from women without endometriosis on day 5 of culture.

CONCLUSION(S)

Our findings confirm the stimulatory effects of IL-8 and its possible role in the pathogenesis of endometriosis. The effects of IL-12 and anti-IL-8 on endometrial cell survival varied according to the disease state and the concentration of the cytokines. Future in vitro studies on the role of anti-IL-8 and IL-12 should aim to use a greater range of concentrations and a higher density of endometrial cells in cultures supplemented with monocytes.