The role of cytokines in endometriosis

Increased α2-6 sialylation of endometrial cells contributes to the development of endometriosis

Endometriosis is a disease characterized by implants of endometrial tissue outside the uterine cavity and is strongly associated with infertility. Focal adhesion of endometrial tissue to the peritoneum is an indication of incipient endometriosis. In this study, we examined the effect of various cytokines that are known to be involved in the pathology of endometriosis on endometrial cell adhesion. Among the investigated cytokines, transforming growth factor-β1 (TGF-β1) increased adhesion of endometrial cells to the mesothelium through induction of α2-6 sialylation. The expression levels of β-galactoside α2-6 sialyltransferase (ST6Gal) 1 and ST6Gal2 were increased through activation of TGF-βRI/SMAD2/3 signaling in endometrial cells. In addition, we discovered that terminal sialic acid glycan epitopes of endometrial cells engage with sialic acid-binding immunoglobulin-like lectin-9 expressed on mesothelial cell surfaces. Interestingly, in an in vivo mouse endometriosis model, inhibition of endogenous sialic acid binding by a NeuAcα2-6Galβ1-4GlcNAc injection diminished TGF-β1-induced formation of endometriosis lesions. Based on these results, we suggest that increased sialylation of endometrial cells by TGF-β1 promotes the attachment of endometrium to the peritoneum, encouraging endometriosis outbreaks.

A growth factor involved in cell differentiation and proliferation contributes to the development of endometriosis by stimulating a protein modification mechanism that increases the adhesiveness of cells lining the uterus. Endometriosis results when these cells, known as endometrial cells, start growing outside the uterus causing pelvic pain, heavy periods and, in some cases, infertility. Ki-Tae Ha at Pusan National University, Yangsan, South Korea, and colleagues found that transforming growth factor-β1 signaling promoted the addition of sialic acid sugar units onto endometrial cell surface proteins. This modification enhanced the adhesion of endometrial cells to mesothelial cells, which line other internal organs, and the formation of endometriosis lesions in mice. Preventing sialic acid binding to its mesothelial cell receptor reduced lesion formation. The findings reveal a new molecular mechanism underlying endometriosis and a potential treatment strategy.

Pathogenesis of endometriosis: the genetic/epigenetic theory

OBJECTIVE

To study the pathophysiology of endometriosis.

DESIGN

Overview of observations on endometriosis.

SETTING

Not applicable.

PATIENT(S)

None.

INTERVENTIONS(S)

None.

MAIN OUTCOME MEASURE(S)

The hypothesis is compatible with all observations.

RESULT(S)

Endometriosis, endometrium-like tissue outside the uterus, has a variable macroscopic appearance and a poorly understood natural history. It is a hereditary and heterogeneous disease with many biochemical changes in the lesions, which are clonal in origin. It is associated with pain, infertility, adenomyosis, and changes in the junctional zone, placentation, immunology, plasma, peritoneal fluid, and chronic inflammation of the peritoneal cavity. The Sampson hypothesis of implanted endometrial cells following retrograde menstruation, angiogenic spread, lymphogenic spread, or the metaplasia theory cannot explain all observations if metaplasia is defined as cells with reversible changes and an abnormal behavior/morphology due to the abnormal environment. We propose a polygenetic/polyepigenetic mechanism. The set of genetic and epigenetic incidents transmitted at birth could explain the hereditary aspects, the predisposition, and the endometriosis-associated changes in the endometrium, immunology, and placentation. To develop typical, cystic ovarian or deep endometriosis lesions, a variable series of additional transmissible genetic and epigenetic incidents are required to occur in a cell which may vary from endometrial to stem cells. Subtle lesions are viewed as endometrium in a different environment until additional incidents occur. Typical cystic ovarian or deep endometriosis lesions are heterogeneous and represent three different diseases.

CONCLUSION(S)

The genetic epigenetic theory is compatible with all observations on endometriosis. Implications for treatment and prevention are discussed.

Clotrimazole is effective for the regression of endometriotic implants in a Wistar rat experimental model of endometriosis

The present work aimed to evaluate molecular, angiogenic and inflammatory changes induced by clotrimazole (CTZ) on endometriosis lesions. For this, thirty female Wistar rats with surgically implanted autologous endometrium were treated with CTZ or vehicle (200 mg/kg) via esophageal gavage for 15 consecutive days. CTZ treatment significantly decreased the growth and the size of the implants, and histological examination indicated regression and atrophy, with no toxicity to the animals. The levels of the angiogenic markers VEGF and VEGFR-2 were significantly decreased in CTZ group. The treatment also promotes a reduction on PGE₂ and TNF-α levels. All these effects involve the amelioration of ERK1/2, Akt, AMPK and PERK signaling upon CTZ treatment. In conclusion, CTZ promoted an overall amelioration of endometriosis in a rat model due to the anti-angiogenic properties of the drug. Therefore, our results support the proposal of a clinical trial using CTZ for the treatment of endometriosis.

Activation of the CXCL16/CXCR6 Axis by TNF-α Contributes to Ectopic Endometrial Stromal Cells Migration and Invasion

The activation of systemic and local inflammatory mechanisms, including elevated levels of chemokines and proinflammatory cytokines in endometriosis progression, is becoming more evident in the recent years. Here, we report the involvement of CXC chemokine 16 (CXCL16) and its sole receptor, CXC chemokine receptor 6 (CXCR6), in pathophysiology of endometriosis. Expression of CXCL16, but not CXCR6, was significantly upregulated in endometriotic lesions when compared to control endometrium. Additionally, serum CXCL16 was significantly elevated in women with endometriosis when compared to control group. Moreover, blockade of the CXCL16/CXCR6 axis by CXCR6 small-interfering RNA reduced the migration and invasion of ectopic endometrial stromal cells (EESCs) followed by decreased phosphorylation of ERK1/2. Furthermore, TNF-α treatment induced the expression of CXCL16 in EESCs. In conclusion, these results suggest that CXCL16/CXCR6 axis, whose expression was enhanced by TNF-α, may be associated with the increased motility of EESCs, through regulation of ERK1/2 signaling, thus contributing to the development of endometriosis. These findings indicate that the CXCL16/CXCR6 axis may contribute to the progression of endometriosis and could be served as a potential target for diagnosis and treatment.

Vasoactive intestinal peptide is upregulated in women with endometriosis and chronic pelvic pain

PROBLEM

Chronic pelvic pain (CPP) causes compromised the quality of life in women with endometriosis and is often attributed to local inflammation and ingrowth of nerve fibers. In this pilot study, we aimed to investigate whether the inflammation-related vasoactive intestinal peptide (VIP) and interleukin (IL)-6 were increased in affected patients.

METHOD OF STUDY

Endometrial and endometriotic tissue biopsy specimens, and serum and peritoneal fluid (PF) samples, were obtained from 85 endometriosis patients and 53 controls. VIP and IL-6 analysis and measurement of microvessel density in tissue were performed using immunohistochemistry, Western blotting, RT-qPCR, and ELISA.

RESULTS

Compared with controls, VIP transcript and protein levels were increased in endometrium from endometriosis patients and further elevated in patients with CPP. In addition, microvessel density, a measurement of angiogenic activity, was increased in the endometrium and in endometriosis lesions in the same subset of patients. Serum and PF levels of VIP and IL-6 were higher in women with endometriosis and CPP compared with endometriosis patients who reported no chronic pain.

CONCLUSION

Vasoactive intestinal peptide is upregulated in endometriosis patients reporting chronic pain. Increased microvessel density in tissue and peritoneal fluid concentrations of IL-6 indicate an elevated inflammation in the pelvic microenvironment of these patients.

Premature Immunosenescence Impairs Immune Surveillance Allowing the Endometriotic Stem Cell to Migrate: The Cytokine Profile as a Common Denominator

While endometriosis, one of the most common reasons for infertility, remains a multifactorial condition and its exact cause highly speculative, there are data pointing to novel pathways of disease initiation which involve a stem cell and its ability to migrate and implant after it differentiates into an endometriotic stem cell. Thus, the mechanisms conferring immune surveillance, which would also normally expel the mesenchymal endometriotic cell, impairing its migration and implantation, appear to be negatively influenced by a state of endometriotic premature immunosenescence. This interplay between the two immunological mechanisms and endometriosis is influenced by a number of common factors having an active role in the host's protection process that inhibits harmful diseases and maintains cellular homeostasis. It appears more than coincidental that production/inhibition of IFN-γ, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-15, IL-18, TNF-α, VEGF, ICAM-1, and the number of Tolllike receptors is the same in immunosenescent states and in conditions with reduced immune surveillance, while the same variations are recorded in endometriotic patients. It is probable that these are common to all process signals, guide the endometriotic stem cell and dictate its fate according to the stochastic, transdifferentiation (plasticity) or deterministic model to become capable of migration and tissue invasion. It is currently unknown whether the pathway taken by the hemopoietic stem cell to become endometriotic represents a normal or aberrant route of development. This prompts research into its isolation and in vitro study of its behavior in order to reveal its potential function and role in endometriosis. (Journal of Endometriosis 2010; 2: 7–18)

[The expression of moesin, p21-activated kinase 4 (PAK 4), matrix metalloproteinases (MMP 2, MMP 9), and CD34 in the eutopic and ectopic endometrium in adenomyosis]

OBJECTIVE

To investigate the expression of moesin, p21-activated kinase 4 (PAK 4), matrix metalloproteinases (MMP 2, MMP 9), and CD34 in the eutopic and ectopic endometrium in different forms of adenomyosis.

MATERIAL AND METHODS

Fifty uteri removed for diffuse adenomyosis and for adenomyomas were examined in reproductive-aged (n=25) and premenopausal (n=25) women. A comparison group included 20 uteri removed for intramural and subserosal fibroids in reproductive-aged and premenopausal women. The investigators performed histological and immunohistochemical (using antibodies to moesin, PAK 4, MMP 2, MMP 9, and CD34) examinations of the eutopic and ectopic endometrium.

RESULTS

Different forms of adenomyosis were characterized by the irregular border of the endometrium and myometrium due to that there were multiple foci of ingrowth of the basal layer of the endometrium through the terminal plate into the myometrium. In both diffuse adenomyosis and adenomyomas, the basal layer of the eutopic and ectopic endometrium differed many (3-8.5) times, showing the higher expression of the enzymes in the epithelial and stromal cells, which affected their invasive activity (moesin, PAK 4, MMP 2 and MMP 9), and the increased number of CD34 cells in its stroma. At the same time, there were no statistically significant differences in their expression in the basal layer of the eutopic and ectopic endometrium in diffuse adenomyosis and adenomyomas.

CONCLUSION

The findings favor the theory of the pathogenesis of adenomyosis due to the invasion of the eutopic endometrium into the myometrium.

Systemic Inflammation Induced by microRNAs: Endometriosis-Derived Alterations in Circulating microRNA 125b-5p and Let-7b-5p Regulate Macrophage Cytokine Production

CONTEXT

Endometriosis is characterized by aberrant inflammation. We previously reported increased levels of microRNA (miRNA) 125b-5p and decreased levels of miRNA Let-7b-5p in serum of patients with endometriosis.

OBJECTIVE

Determine the regulatory function of miRNAs 125b-5p and Let-7b-5p on production of proinflammatory cytokines in endometriosis.

DESIGN

Case-control study.

SETTING

University hospital.

PATIENTS

Women with (20) and without (26) endometriosis; human U937 macrophage cell line.

INTERVENTION

Sera were collected from surgically diagnosed patients and differentiated U937 cells that were transfected with miRNAs 125b-5p and Let-7b-5p mimics and inhibitor.

MAIN OUTCOME MEASURES

Enzyme-linked immunosorbent assay for tumor necrosis factor-α (TNF-α), interleukin (IL)-6, IL-8, and IL-1β levels and quantitative real-time polymerase chain reaction for expression of miRNAs 125b-5p and Let-7b-5p in sera of patients with and without endometriosis. Transfected macrophages were evaluated for expression of inflammatory cytokines, intracellular production, and secretion of these cytokines.

RESULTS

We noted substantial elevation of TNF-α, IL-1β, and IL-6, marked upregulation of miRNA 125b, and considerable downregulation of Let-7b in sera of patients with endometriosis vs control. There was a positive correlation between miRNA 125b levels and TNF-α, IL-1β, and IL-6 and a negative correlation between miRNA Let-7b levels and TNF-α in sera of patients with endometriosis. Transfection experiments showed a noteworthy upregulation of TNF-α, IL-1β, IL-6, and IL-8 in macrophages transfected with miRNA 125b mimic or Let-7b inhibitor. The secreted cytokine protein levels and intracellular imaging studies closely correlate with the messenger RNA changes.

CONCLUSIONS

Endometriosis-derived miRNAs regulate macrophage cytokine production that contributes to inflammation associated with this condition.

Efficacies of vitamin D and omega-3 polyunsaturated fatty acids on experimental endometriosis

OBJECTIVE

The aim of this study was to investigate the effects of 1,25-dihydroxyvitamin-D3 (vitamin D) and omega-3 polyunsaturated fatty acids (omega-3 PUFA) on experimentally induced endometriosis in a rat model.

MATERIALS AND METHODS

A prospective, single-blind, randomized, controlled experimental study was performed on 30 Wistar female rats. Endometriosis was surgically induced by implanting endometrial tissue on the abdominal peritoneum. Four weeks later, a second laparotomy was performed to assess pre-treatment implant volumes and cytokine levels. The rats were randomized into three groups: vitamin D group (42 μg/kg/day), omega-3 PUFA group (450 mg/kg/day), and control group (saline 0.1 mL/rat/day). These treatments were administered for 4 weeks. At the end of treatment, a third laparotomy was performed for the assessment of cytokine levels, implant volumes (post-treatment) and implants were totally excised for histopathologic examination. Pre- and post-treatment volumes, cytokine levels within the groups, as well as stromal and glandular tissues between the groups were compared.

RESULTS

The mean post-treatment volume was statistically significantly reduced in the omega-3 PUFA group (p=0.02) and the level of the interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), vascular endothelial growth factor (VEGF) in the peritoneal fluid were significantly decreased at the end of treatment in the omega-3 PUFA group (p=0.02, p=0.03, and p=0.03, respectively). In the vitamin D group, only IL-6 levels were significantly decreased. In the histopathologic examination, the glandular tissue and stromal tissue scores of the implants were significant lower in the omega-3 PUFA group (p=0.03 and p=0.02).

CONCLUSION

Omega-3 PUFA caused significant regression of endometriotic implants. Vitamin D has not been as effective as omega-3 PUFA on endometriosis.

Glycyrrhizin inhibits LPS-induced inflammatory mediator production in endometrial epithelial cells

Endometriosis is a continuous inflammation of uterine endometrium that usually affects women of reproductive age. Glycyrrhizin, a triterpene isolated from the roots and rhizomes of licorice (Glycyrrhiza glabra), has been known to have anti-inflammatory effect. The purpose of this study was to investigate the anti-inflammatory effect of glycyrrhizin on LPS-stimulated mouse endometrial epithelial cells (MEEC). The levels of TNF-α, IL-1β, and PGE₂ were measured by ELISA. The expression of COX-2, iNOS, TLR4, and NF-ĸB were detected by western blot analysis. The results showed that glycyrrhizin significantly suppressed LPS-induced TNF-α, IL-1β, NO, and PGE₂ production. Also, LPS-induced iNOS and COX-2 expression were attenuated by glycyrrhizin. Furthermore, glycyrrhizin significantly attenuated TLR4 expression and NF-κB activation induced by LPS in MEEC. In conclusion, the present study demonstrated that glycyrrhizin inhibited LPS-induced inflammatory response by inhibiting TLR4 signaling pathway in MEEC. Glycyrrhizin may be used as a potential agent for the treatment of endometriosis.

Resveratrol and endometriosis: In vitro and animal studies and underlying mechanisms (Review)

Endometriosis is characterized by the existence of endometrial tissue and stroma exterior to the uterus. Despite the high prevalence, the etiology of endometriosis remains elusive. The search for the most promising compounds for treatment of endometriosis has led to the identification of resveratrol. Resveratrol, a plant-derived polyphenolic phytoalexin, demonstrates broad-spectrum health beneficial effects, including anti-proliferative, anti-inflammatory, antineoplastic and antioxidant. Because of these properties and its wide distribution in plants, resveratrol is proposed as a great potential to treat endometriosis. In animal models of endometriosis, resveratrol supplementation has displayed beneficial results as it decreased the number and volume of endometrial implants, suppressed proliferation, vascularization, inflammation, cell survival and increased apoptosis. On the other hand, resveratrol treatment in-vitro studies, reduced invasiveness of endometriotic stromal cells (ESCs) and suppressed their inflammatory responses. In this review, we will summarize the recent studies in in-vitro and animal studies on resveratrol and endometriosis.

Hydrosalpinx: Tubal surgery or in vitro fertilisation? An everlasting dilemma nowadays; a narrative review

The decision on how to treat tubal diseases, specifically hydrosalpinx, is a difficult one. Ιt involves surgical, medical, social, emotional and economic factors. This narrative review aims to increase awareness of tubal disease diagnosis and treatment, to compare between tubal surgery and in vitro fertilisation (IVF) for tubal factor infertility, and to investigate the effect of the combination of both. This way, we can be more effective, safe and provide our patients with better treatment results. The review analysed randomised studies, trials and meta-analysis, which give new aspects on the treatment methods for tubal pathology before IVF. Recent papers published in English have been studied, alongside guidelines and committee opinions from previous years. Tubal surgery and IVF aim to exploit a woman's reproductive potential. IVF and endoscopic tubal surgery must be thought of as complementary, rather than competing techniques in tubal disease cases, in order to improve fertility outcome. The first-line treatment for young women less than 35 years old with minor tubal pathology, is tubal surgery. IVF should be offered if there are other factors in a couple's subfertility, if the patient is >38 years old, if moderate to severe tubal disease is present, and if it has been more than 12 months post-surgery.

Endometriosis-associated changes in serum levels of interferons and chemokines

BACKGROUND/AIM

The aim of the study was to evaluate the serum concentration of main chemokines and interferons in patients with diagnosed endometriosis.

MATERIALS AND METHODS

A total of 160 women were divided in two study groups (group 1 - endometriosis; group 2 - healthy women). Serum levels of IFN-α, IFN-γ, MCP-1, MIP-1α, MIP-1β, RANTES, eotaxin, IL-8, MIG, IP-10, and IL-17A were measured with Human Multiplex Cytokine Panels. Results. Serum levels of IFN-γ, MCP-1, and IL-8 were significantly higher (mean 14.03, 57.24, and 534.24, respectively, compared to 0.58, 20.51, and 259.82, respectively), and serum levels of IP-10 and eotaxin were significantly lower in women with endometriosis compared to the controls (mean 1.15 and 1.01, respectively, compared to 3.90 and 3.22, respectively). Conclusions. According to our results women with endometriosis have elevated levels IFN-γ, MCP-1, and IL-8, and lower serum levels of IP-10 and eotaxin, indicating unbalanced immune activity in endometriosis.

Co-culture with macrophages enhances the clonogenic and invasion activity of endometriotic stromal cells

OBJECTIVE

To study the effect on endometrial and endometriotic cells after co-culture with macrophages, using clonogenic, invasion and self-renewal assays.

MATERIALS AND METHODS

Peripheral blood samples, endometrium and endometriotic tissues were collected. Autologous macrophages were co-cultured with endometrial and endometriotic cells. The number of colony-forming units (CFU), invasiveness and self-renewal activity after co-culture with macrophages were determined. The cytokine level of colony-stimulating factor-1 (CSF-1) from macrophages with and without endometriosis was compared.

RESULTS

Co-culture with macrophages significantly increased the clonogenic and invasion ability of endometriotic stromal cells in vitro. Colony-stimulating factor-1 (CSF-1) was up-regulated in endometriotic macrophages conditioned medium when compared to those without the disease.

CONCLUSIONS

These data suggest that macrophages may increase the proliferation and invasion activity of stromal clonogenic cells in women with endometriosis.

Wenshen Xiaozheng Tang induces apoptosis and inhibits migration of ectopic endometriotic stromal cells

ETHNOPHARMACOLOGICAL RELEVANCE

Wenshen Xiaozheng Tang (WXT), a traditional Chinese medicine prescription, exerted a good therapeutic effect on endometriosis. However, the underlying mechanism is unclear. In the present study, we sought to evaluate the effect of WXT on the proliferation and migration of ectopic endometriotic stromal cells and explore the potential molecular mechanism.

MATERIALS AND METHODS

Primary stromal cells derived from ectopic endometriotic lesions of patients with endometriosis were isolated and cultured. The inhibition effect of WXT on cell proliferation was determined by MTT. Apoptosis of ectopic endometriotic cells treated with WXT was analyzed with Annexin V-FITC/7-AAD staining. The activation of caspases was detected by western blot analysis. The influence of WXT on migration of ectopic endometriotic cells was measured by scratch wound healing assay and Transwell assay. The DNA binding activity of NF-κB and the expression of nuclear p65 protein were determined by electrophoretic mobility shift assay and western blot analysis, respectively. The impact of WXT on the expression of NF-κB regulated gene products involved in apoptosis and migration was determined by western blot analysis.

RESULTS

WXT inhibited the proliferation of ectopic endometriotic cells in a time- and dose-dependent manner. In addition, WXT treatment resulted in significant induction of apoptosis through the activation of caspases and inhibition of migration in ectopic endometriotic cells. WXT notably suppressed constitutive NF-κB-DNA-binding activity as well as TNF-α induced nuclear translocation of NF-κB p65 subunit in ectopic endometriotic cells. Moreover, WXT diminished the expression of NF-κB regulated gene products involved in apoptosis and migration, including c-IAP1, c-IAP2, XIAP, survivin, Mcl-1, COX-2 and MMP-9.

CONCLUSIONS

Our results indicate that WXT induces apoptosis and inhibits migration of ectopic endometriotic stromal cells.

Role of Versican in the Pathogenesis of Peritoneal Endometriosis

CONTEXT

Sampson's theory cannot explain why only some cycling women develop peritoneal endometriosis. Few studies have focused on the pelvic peritoneum, which receives regurgitated endometrial tissues. We hypothesized that molecular alterations in the peritoneum are involved in the development of peritoneal endometriosis and conducted a microarray analysis to compare macroscopically normal peritoneum sampled from women with peritoneal endometriosis (endometriotic peritoneum) and those without (non-endometriotic peritoneum). Versican, a major proteoglycan component of the extracellular matrix, is one of the molecules up-regulated in endometriotic peritoneum.

OBJECTIVE

To investigate the role of versican in peritoneal endometriosis. Design, Patients, and Main Outcome Measure: Endometriotic peritoneum and non-endometriotic peritoneum were subjected to RT-PCR, immunostaining, and Western blotting. The versican V1 isoform was stably transfected into Chinese hamster ovary cells (CHO-V1), and the effects of CHO-V1-derived conditioned medium (V1-CM) on primary human endometrial stromal cells were investigated with attachment, invasion, and proliferation assays. The effects of peritoneal fluid collected from endometriotic women (endometriotic PF) or cytokines/growth factors, which were shown to be elevated in endometriotic PF, on versican expression in a human peritoneal cell line (HMrSV5) were also examined.

RESULTS

Versican V1 expression levels were significantly higher in endometriotic peritoneum. In vitro, V1-CM promoted attachment to the HMrSV5 cell monolayer as well as the Matrigel invasion of endometrial stromal cells. Although versican V1 expression was up-regulated by TGF-β1 in HMrSV5 cells, it remained unchanged in endometriotic PF.

CONCLUSIONS

Our results suggest the involvement of peritoneal versican in the development of peritoneal endometriosis.

Polymorphisms of ICAM-1 and IL-6 genes related to endometriosis in a sample of Brazilian women

PURPOSE

This study investigated the possibility of K469E (rs5498) and G241R (rs1799969) polymorphisms, in ICAM-1 gene, and G634C (rs1800796), in IL-6 gene, being associated with the occurrence of endometriosis in a sample of Brazilian women.

METHODS

We genotyped 200 women (100 in control group and 100 in endometriosis group) by PCR-RFLP technique for G634C, K469E, and G241R polymorphisms.

RESULTS

No significant difference was observed in genotypic frequency between control and endometriosis groups for G634C and K469E polymorphisms (p = 0.61 and p = 0.22, respectively). In addition, no significant difference between stages I-II and III-IV of the disease was found for both SNPs (p = 0.63 and p = 0.24, respectively). All individuals were wild homozygotes for G241R polymorphism.

CONCLUSION

This study suggests that polymorphisms K469E, G241R, and G634C are not associated with increased susceptibility to endometriosis in Brazilian women.

Leflunomide—an Immunomodulator—Induces Regression of Endometrial Explants in a Rat Model of Endometriosis

OBJECTIVE

To test if leflunomide, an immunomodulator, could impede the growth of an ectopic uterine tissue.

METHODS

Endometriosis was surgically induced in 26 rats by transplanting an autologous fragment of endometrial tissue onto the inner surface of the abdominal wall. Four weeks later two rats were killed. The volume and weight of the implants were measured. The remaining rats were randomly grouped, and in group 1 no medication was given. To the rats in group 2, 35 mg/kg/d of leflunomide was administered orally. Four weeks later, rats were killed and ectopic uterine tissues were reevaluated morphologically and histologically. A scoring system was used to evaluate preservation of epithelia.

RESULTS

Two rats in the control group died 5 weeks after surgery. There was a significant difference in post-treatment spherical volumes (139.1 +/- 92.8 versus 33.5 +/- 12.5 mm3) and explant weights (156.3 +/- 105.6 versus 38.6 +/- 12.6 mg) between the control and leflunomide-treated groups. The epithelia were found to be preserved significantly better in the control group when compared with the leflunomide-treated group (median 2.5 [interquartile range, 1.25] versus median 1.00 [interquartile range, 1.5]).

CONCLUSION

Leflunomide appeared to cause regression of experimental endometriosis in rats.

Effect of Lignocaine on IL-6, IL-8, and MCP-1 in Peritoneal Macrophages and Endometriotic Stromal Cells

OBJECTIVE

The objective was to evaluate the effect of lignocaine on cytokine expression and secretion in vitro in peritoneal fluid macrophages and endometriotic stromal cells.

DESIGN

Experimental in vitro study on human cells.

POPULATION AND SAMPLE

Peritoneal fluid (n = 10) and samples from endometriotic cysts (n = 7) were collected from 13 women (women with endometriosis n = 8, and healthy controls n = 5) during surgery for clinical reasons.

METHODS

Macrophages from the peritoneal fluid and cells from the inside of the endometriotic cysts capsules were isolated and cultivated for 24 to 48 hours in medium with and without the supplement of lignocaine 0.1 or 1.0 mg/mL. Relative gene expression of monocyte chemotactic protein 1 (MCP-1), interleukin 6 (IL-6), and IL-8 was evaluated with quantitative polymerase chain reaction and compared between treated and untreated cells with Wilcoxon matched pairs. The concentrations of MCP-1, IL-6, and IL-8 were measured using enzyme-linked immunosorbent assay and were compared between treated and untreated cells with Wilcoxon matched pairs.

RESULTS

The gene expression and protein secretion of IL-8 in endometriotic stromal cells after incubation with lignocaine 0.1 mg/mL were significantly decreased after 24 hours compared to the controls ( P = .028 and P = .018). Macrophages from healthy controls had a significant lower gene expression of all tested cytokines ( P = .043) after treatment with lignocaine, but there were no significant differences in protein level. Macrophages from women with endometriosis showed diverging results since 3 of 5 samples showed increased gene expression of 1 (n = 2) or 2 cytokines (n = 1) after lignocaine treatment.

CONCLUSION

Lignocaine can affect the gene expression and secretion of some proinflammatory cytokines in vitro.

Tranylcypromine, a lysine-specific demethylase 1 (LSD1) inhibitor, suppresses lesion growth and improves generalized hyperalgesia in mouse with induced endometriosis

BACKGROUND

Growing evidence indicates that endometriosis is an epigenetic disease. Encouragingly, histone deacetylases (HDACs) and DNA methyltransferases have been shown to be promising targets by numerous in vitro studies. However, only a few studies have shown promising effects of HDAC inhibition in preclinical studies in endometriosis. While lysine-specific demethylase 1 (LSD1) is recently found to be aberrantly expressed in endometriosis, and that the treatment of endometriotic stromal cells with tranylcypromine (TC), an LSD1 inhibitor, significantly reduced cellular proliferation, cell cycle progression, and invasiveness, the in vivo effect of TC treatment is currently lacking. This study sought to evaluate the effect of TC in a mouse model of endometriosis.

METHODS

Forty-seven female C57BL/6 mice were used in this experimentation. All mice, except those randomly selected to form Sham surgery (M) and specificity control (S) groups, received an endometriosis-inducing surgery. Group S was set up mainly to ensure that the reduced generalized hyperalgesia in mice treated with TC is not due to any possible analgesic effect of TC, but rather resulting from the treatment effect specific to endometriosis. Two weeks after the surgery, mice that received surgery were further divided randomly into 3 groups: 1) untreated group (U); 2) low-dose TC group (L); 3) high-dose TC group (H). Group S received the same treatment as in group H. Two weeks after treatment, all mice were sacrificed and their ectopic endometrial tissues were harvested and analyzed by immunohistochemistry analysis. Hotplate test was administrated to all mice before the induction, treatment and sacrifice. Lesion size, hotplate latency, immunoreactivity against markers of proliferation, angiogenesis, H3K4 methylation, and of epithelial-mesenchymal transition (EMT).

RESULTS

TC treatment significantly and substantially reduced the lesion size and improved generalized hyperalgesia in a dose-dependent fashion in mice with induced endometriosis. In addition, TC treatment resulted in reduced immunoreactivity to biomarkers of proliferation, angiogenesis, and H3K4 methylation, leading to arrested EMT and lesion growth.

CONCLUSION

In light of our previously reported reduced cellular proliferation, cell cycle progression and invasiveness resulting from the LSD1 inhibition in in vitro studies, our data strongly suggest that LSD1 is a promising therapeutic target for endometriosis.

TRIAL REGISTRATION

Not applicable.

Endometriosis-Derived Stromal Cells Secrete Thrombin and Thromboxane A2, Inducing Platelet Activation

Platelets have been recently revealed to play important roles in the development of endometriosis. However, it is unclear whether endometriotic lesions can secrete any platelet inducers outside the menstruation window. Hence, this study was undertaken to see whether endometriosis-derived stromal cells secrete platelet activators and cause platelet activation. We employed in vitro experimentation using primary ectopic endometrial stromal cells (EESCs) and platelets from healthy male volunteers and evaluated the extent of platelet aggregation by aggregometer and the platelet activation rate by flow cytometry using supernatants harvested from EESCs of different cell densities. We also measured the concentration of thromboxane B2 (TXB2), a metabolite of thromboxane A2 (TXA2), and thrombin activity in supernatants harvested from EESCs of different densities and evaluated the extent of platelet aggregation after treatment of EESCs with hirudin, Ozagrel, and apyrase. Finally, the concentration of TXB2, thrombin, and transforming growth factor β1 (TGF-β1) in platelets cocultured with different densities of EESCs is measured by enzyme-linked immunosorbent assay. We found that EESCs secrete thrombin and TXA2 and induce platelet activation and aggregation in a density-dependent fashion. Treatment of platelets with EESCs resulted in increased concentration of TXB2, thrombin, and TGF-β1 in a density-dependent manner. Treatment of EESCs with hirudin and Ozagrel, but not apyrase, resulted in significant suppression of platelet aggregation. Thus, given recently reported effects of activated platelets on the cell behaviors of EESCs and endometriotic lesions in general, our findings establish that endometriotic lesions and platelets engage active cross-talks in the development of endometriosis, highlighting the importance of lesion microenvironment in endometriosis.

Endometriosis and cancer

Endometriosis is manifested by the presence of both endometrial glandular and stromal cells outside the uterine cavity. It is characterized by ectopic implantation of endometrial cells with elevated proliferation and migration. Endometriosis is the leading cause of morbidity among premenopausal women and the complex pathogenesis of this disease remains controversial despite extensive research. This rather complex disease has a significant impact on quality of life of many women as none of the current treatments represent a cure. Based on the current knowledge, one can conclude that the histological and genetic alterations in endometriosis might explain why and how endometriosis can change into several types of cancer. However, the exact mechanisms of this conversion are still not fully established.

Serum anti-inflammatory cytokines for the evaluation of inflammatory status in endometriosis

Background:

Endometriosis is a frequent gynecologic disease with a severe impact on the quality of life in the affected women; its pathogenesis is yet to be fully understood, with an altered immunity as a possible key factor. The present study aimed to investigate the serum anti-inflammatory cytokine profile in the patients with endometriosis compared with the healthy controls.

Materials and Methods:

One hundred and sixty women were included, divided into two study groups (Group I — endometriosis; Group 2 — healthy women). We evaluated the serum levels of interleukin-1 receptor antagonist (IL-1Ra), IL-2, IL-2R, IL-4, IL-10, IL-13, and IL-15 with the use of Human multiplex cytokine panels. Statistical analyses (normality distribution analysis, independent t-test, Mann–Whitney U-test) were performed using IBM SPSS software (version 22.0) and GraphPad Prism (version 5.00); receiver operating characteristic curve were used to demonstrate the diagnostic performance of the studied markers.

Results:

The mean serum level of IL-1Ra, IL-4, and IL-10 were significantly higher in women with endometriosis compared to women free of disease from the control group (30.155, 138.459, and 1.489, respectively, compared to 14.109, 84.710, and 0.688, respectively; P < 0.001, P < 0.001, and P = 0.002, respectively.). No significant differences in the mean serum levels of IL-2, IL-13, and IL-15 were observed between the studied groups and IL-2R had a very low detection rate.

Conclusion:

Endometriosis is associated with elevated levels of anti-inflammatory cytokines, IL-1Ra, IL-4, and IL-10, markers that have a potential role as a prognostic factor for endometriosis.

Asymmetric dimethylarginine (ADMA), nitric oxide metabolite, and estradiol levels in serum and peritoneal fluid in women with endometriosis

BACKGROUND

Increase in nitric oxide (NO) concentration accompanied by alteration in peritoneal immune defense reactions is involved in the pathogenesis of endometriosis. Asymmetric dimethylarginine is an endogenous competitive inhibitor of NO synthase. This study was designed to compare NO metabolite (nitrite), asymmetric dimethylarginine, and estradiol concentrations in serum and peritoneal fluid (PF) of patients with and without endometriosis.

MATERIALS AND METHODS

Subjects were assigned to two groups based on their laparoscopic results. The groups consisted of women with and without endometriosis (90 and 89 participants, respectively). The serum and peritoneal levels of nitrite (stable NO metabolite), asymmetric dimethylarginine, and estradiol were measured using enzyme-linked immunosorbent assay (ELISA) kits. These parameters were analyzed and compared between the groups statistically using SPSS software version 16.

RESULTS

Both nitrite and asymmetric dimethylarginine levels were significantly higher in the serum of the participants from both groups than those in the PF group (P < 0.05). However, no significant difference in the asymmetric dimethylarginine level was detected between the two groups. In addition, the PF level of nitrite increased significantly in patients with endometriosis when compared with non-endometriosis subjects (P < 0.05). The PF levels of estradiol in both groups were significantly higher than the serum levels of estradiol (P < 0.05).

CONCLUSIONS

The NO metabolite level of PF implies the possible role of NO in the pathogenesis of endometriosis.

Effect of Bushenwenyanghuayu decoction on nerve growth factor and bradykinin/bradykinin B1 receptor in a endometriosis dysmenorrhea mouse model

OBJECTIVE

To observe the effects of Bushenwenyanghuayu decoction (BD), a Traditional Chinese Medicine (TCM), on the serum concentration of nerve growth factor (NGF) and bradykinin (BK), and protein and mRNA levels of NGF and bradykinin B1 receptor (BKB1R) in a mouse model of endometriosis dysmenorrhea.

METHODS

Seventy-five experimental female BALB/c mice were randomly divided into five groups, 15 mice each: sham, model, BD high dose (61.67 g/kg), BD low dose (15.42 g/kg), and gestrinone (0.4 mg/kg) groups. All the mice except for those in the sham group underwent auto-transplantation surgery and were gavaged estradiol valerate (0.5 mg/kg, daily for 12 days) after surgery. On the 12th day, 1 h after administration, writhing response was induced by intraperitoneal injection of oxytocin at 2 U/mouse. The writhing frequency and latency were recorded and the volume of the ectopic foci was measured. The concentration of serum NGF and BK was detected by enzyme-linked immunosorbent assay, the protein expression of NGF and BKB1R was tested by immunohistochemistry and western blotting, and NGF and BKB1R mRNAs were detected by real-time PCR.

RESULTS

Compared with the model group, the volume of the ectopic foci in the treatment groups was significantly lower (P < 0.01), the writhing frequency was decreased (P < 0.05), and the writhing latency was prolonged (P < 0.01). Compared with the sham group, serum NGF and BK levels in the model group were significantly increased (P < 0.01). There were positive correlations for writhing frequency among the NGF and BK groups (P < 0.01). The serum NGF and BK levels were significantly lower in the treatment groups than the model group (P < 0.05). The protein expression of NGF, BKB1R was significantly decreased in the treatment groups compared with the model group (P < 0.01). NGF and BKB1R mRNA expression was significantly decreased in the treatment groups compared with the model group (P < 0.01).

CONCLUSION

NGF and BK/BKB1R may play an important role in the development of endometriosis-associated dysmenorrhea, and BD was found to inhibit the development of endometriosis and relieve dysmenorrhea by influencing NGF and BK/ BKB1R mRNA and protein levels.

Lipoxin A4 suppresses the development of endometriosis in an ALX receptor-dependent manner via the p38 MAPK pathway

BACKGROUND AND PURPOSE

Lipoxins can function as endogenous 'breaking signals' in inflammation and play important roles in the progression of endometriosis. In this study, we further investigated the molecular mechanism by which lipoxin A4 (LXA4 ) suppresses the development of endometriosis.

EXPERIMENTAL APPROACH

Primary endometriotic stromal cells (ESCs) were treated with IL-1β, or pre-incubated with LXA4 before incubation with IL-1β. The LXA4 receptor (ALX receptor) antagonist Boc-2 and gene-silencing approaches were used to study the involvement of the ALX receptor in anti-inflammatory signalling responses in ESCs. An animal model of endometriosis was induced in BALB/c mice by i.p. injection of an endometrium-rich fragment.

KEY RESULTS

Decreased levels of LXA4 and 15-LOX-2 expression but increased expression of AXL receptors were observed in endometriotic tissues. LXA4 inhibited the release of inflammatory factors and phosphorylation of p38 MAPK in IL-1β-induced ESCs, an effect mediated by ALX receptors. LXA4 inhibited the proliferation of ESCs, as indicated by reduced DNA replication, caused G0 /G1 phase cell cycle arrest and down-regulated the expression of proliferating cell nuclear antigen in ESCs. LXA4 also attenuated the invasive activity of ESCs mainly by suppressing the expression and activity of MMP-9. In vivo, we further confirmed that LXA4 could inhibit the progression of endometriosis by acting as an anti-inflammatory.

CONCLUSIONS AND IMPLICATIONS

LXA4 exerted anti-inflammatory, anti-proliferative and anti-invasive effects on endometriosis through a mechanism that involved down-regulating the activities of p38 MAPK, which was mediated by ALX receptors.

Effect of Pioglitazone on Production of Regulated upon Activation Normal T-cell Expressed and Secreted (RANTES) and IVF Outcomes in Infertile Women with Endometriosis

This study was performed to investigate the effect of peroxisome proliferators activated receptor-γ (PPAR-γ) ligand, pioglitazone, on production of regulated upon activation normal T-cell expressed and secreted (RANTES) and in vitro fertilization (IVF) outcome in infertile patients with endometriosis. Sixty-four infertile patients with stage III or IV endometriosis undergoing IVF were randomly allocated to the study or the control group. The long protocol of GnRH agonist (GnRH-a) was used for controlled ovarian stimulation (COS) in all patients. Patients in the study group were treated with pioglitazone at a dose of 15 mg/day orally from the starting day of GnRH-a treatment to the day of hCG injection. Blood samples were drawn for serologic assay of RANTES on the first day of GnRH-a treatment and the day of hCG injection. There were no differences between the study and control groups in patient characteristics. There were also no differences between the two groups in COS duration, and the numbers of retrieved oocytes, fertilized oocytes and embryos transferred. The clinical pregnancy rate per cycle was higher in the study group, but this difference was not statistically significant. However, embryo implantation rate was significantly higher in the study group of 12.5% compared with 8.6% in the control group (P<0.05). The serum RANTES levels after pioglitazone treatment were significantly lower than those before pioglitazone treatmen in the study group (P<0.05). Our data suggest that pioglitazone treatment can suppress RANTES production and improve the embryo implantation rate in patients with endometriosis undergoing IVF.

Pro-inflammatory cytokines for evaluation of inflammatory status in endometriosis

THE AIM OF THE STUDY

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Increased expression of p21-activated kinase 4 in adenomyosis and its regulation of matrix metalloproteinase-2 and -9 in endometrial cells

OBJECTIVE

To investigate the expression of p21-activated kinase 4 (Pak4) in both adenomyotic foci and the eutopic endometrium of women with adenomyosis, and whether the activities of matrix metalloproteinases (MMPs)-2 and -9 are regulated by Pak4 in endometrial cells.

DESIGN

Experimental study using human samples and cell lines.

SETTING

University hospital.

PATIENT(S)

Thirty-nine patients with histologic evidence of adenomyosis, and 34 patients with carcinoma in situ of the uterine cervix without adenomyosis or endometriosis.

INTERVENTION(S)

Immunohistochemistry, zymography after transfection with Pak4 small interfering RNA (siRNA), and western blot analyses after nuclear factor kappa-B (NF-кB) inhibitor treatment.

MAIN OUTCOME MEASURE(S)

The Pak4 immunoreactivity of women with vs. without adenomyosis was compared semiquantitatively. The activities of MMP-2 and -9 were analyzed in eutopic endometrial stromal cells and Ishikawa cells after transfection with Pak4 siRNA. The Pak4 expression was evaluated in endometrial cells after treatment with NF-кB inhibitor.

RESULT(S)

Pak4 immunoreactivity was increased in adenomyotic foci and in the eutopic endometrium of women with adenomyosis. Transfection of endometrial cells with Pak4 siRNA led to significant decreases of MMP-2 and -9 activities. In vitro treatment of endometrial cells with tumor necrosis factor-alpha caused a significant increase of NF-кB activation and Pak4 expression, which was obviously decreased by the NF-кB inhibitor pyrrolidinedithiocarbamate.

CONCLUSION(S)

Our results suggest that Pak4 is regulated by NF-кB and that increased Pak4 expression can lead to development of adenomyosis by enhancing the invasiveness of endometrial cells through regulation of MMP-2 and -9 activities.

Is resveratrol a potential substitute for leuprolide acetate in experimental endometriosis?

OBJECTIVE

Resveratrol, a phytoalexin polyphenol, has anti-angiogenic, antioxidant, anti-inflammatory properties. We aimed to compare the anti-inflammatory and anti-angiogenic effects of resveratrol and leuprolide acetate (LA) in an experimental endometriosis model.

STUDY DESIGN

A prospective experimental study was conducted in a University Surgical Research Center. Thirty-three non-pregnant female Sprague-Dawley rats, in which experimental model of endometriosis were surgically induced were randomly divided into four groups. Group 1 was administered 30 mg/kg resveratrol i.m. for 14 days, group 2 was given 1mg/kg s.c. single dose LA, group 3 was administered both resveratrol and LA, and group 4 had no medication. After two weeks medication rats were sacrificed and size, histopathology and immunreactivity to matrix metalloproteinase (mmp)2, mmp9, vascular endothelial growth factor (VEGF) of the endometriotic implants were evaluated. Plasma and peritoneal fluid levels of interleukin (IL)-6, IL-8, and tumor necrosis factor-α (TNF-α) were analyzed.

RESULTS

The endometriotic implant volumes, histopathological grade and immunreactivity to mmp2, mmp9 and VEGF were significantly reduced (p<0.001), and plasma and peritoneal fluid levels of IL-6, IL-8 and TNF-α were significantly decreased in group 1 and group 2 in comparison to group 3 and group 4 (p < 0.001).

CONCLUSION

Resveratrol alone is a potential agent for the treatment of endometriosis and may be an alternative to LA. In contrast, the combination of LA and resveratrol decreased the anti-inflammatory and anti-angiogenic effects of each agent. Since resveratrol is widely used as an alternative therapy for a variety of conditions, it can undermine the effectiveness of LA. Therefore, caution should be exercised when used in combination with other agents.

Complement pathway is frequently altered in endometriosis and endometriosis-associated ovarian cancer

PURPOSE

Mechanisms of immune dysregulation associated with advanced tumors are relatively well understood. Much less is known about the role of immune effectors against cancer precursor lesions. Endometrioid and clear-cell ovarian tumors partly derive from endometriosis, a commonly diagnosed chronic inflammatory disease. We performed here a comprehensive immune gene expression analysis of pelvic inflammation in endometriosis and endometriosis-associated ovarian cancer (EAOC).

EXPERIMENTAL DESIGN

RNA was extracted from 120 paraffin tissue blocks comprising of normal endometrium (n = 32), benign endometriosis (n = 30), atypical endometriosis (n = 15), and EAOC (n = 43). Serous tumors (n = 15) were included as nonendometriosis-associated controls. The immune microenvironment was profiled using Nanostring and the nCounter GX Human Immunology Kit, comprising probes for a total of 511 immune genes.

RESULTS

One third of the patients with endometriosis revealed a tumor-like inflammation profile, suggesting that cancer-like immune signatures may develop earlier, in patients classified as clinically benign. Gene expression analyses revealed the complement pathway as most prominently involved in both endometriosis and EAOC. Complement proteins are abundantly present in epithelial cells in both benign and malignant lesions. Mechanistic studies in ovarian surface epithelial cells from mice with conditional (Cre-loxP) mutations show intrinsic production of complement in epithelia and demonstrate an early link between Kras- and Pten-driven pathways and complement upregulation. Downregulation of complement in these cells interferes with cell proliferation.

CONCLUSIONS

These findings reveal new characteristics of inflammation in precursor lesions and point to previously unknown roles of complement in endometriosis and EAOC.