Treating endometriosis as an autoimmune disease

The role of the B lymphocytes in endometriosis: A systematic review

The physiopathology of endometriosis is not completely understood and its progression is associated with a local and systemic inflammatory reaction. It is important to clarify the potential role of the immune system to better understand its implication in the pathogenesis of endometriosis, which includes the study of the role of B cells and antibodies. The aim of this study was to review the literature about the role of B lymphocytes in endometriosis. A search for "endometriosis", "B cells" and "B lymphocytes" in databases resulted in 140 citations; after applying inclusion and exclusion criteria, a total of 22 studies were assessed. The analyzed samples in the studies varied and different markers and techniques were used by the authors to evaluate the direct or indirect role of B lymphocytes in endometriosis. Most studies demonstrated increased number and/or activation of B cells while seven studies found no difference and two studies showed decreased number of B cells. Increased B lymphocytes and excessive production of autoantibodies in endometriosis have been described in the literature, but their role in the development of the disease is not well understood. Moreover, the association of these factors with clinical symptoms, location and severity of the disease has not been investigated. Further studies are necessary to clarify the role of B cells in the development of endometriosis and propose new therapeutic strategies such as the use of drugs that target these cells.

Circulating and peritoneal fluid interleukin-6 levels and gene expression in pelvic endometriosis

Current data are inconsistent regarding the association between interleukin-6 (IL-6), a marker of acute phase inflammation, and pelvic endometriosis. The aim of the present study was to assess IL-6 levels in serum and peritoneal fluid (PF), as well as IL-6 gene expression in adipose tissue (AT) and endometrial samples in pelvic endometriosis. A total of 30 patients with endometriosis and 18 women with a normal pelvis were enrolled in this case-control study. IL-6 levels in PF and serum were determined using a human enzyme-linked immunosorbent assay and IL-6 gene expression was evaluated using reverse transcription-quantitative polymerase chain reaction. It was observed that IL-6 levels in the PF were higher in patients with endometriosis than in the control group (P=0.047) and patients with stage III/IV endometriosis exhibited higher IL-6 levels in the PF than those with stage I/II endometriosis and the control group (P<0.001). Furthermore, a strong correlation between PF IL-6 levels and the revised American Society for Reproductive Medicine score for endometriosis severity was identified (r=0.77; P<0.001). IL-6 gene expression did not differ significantly between endometriosis and control groups in endometrial samples or in AT of both groups. The results of the current study suggest that there may be an association between IL-6 and the presence and severity of pelvic endometriosis. The source of this higher IL-6 seems not to be specifically related to regional AT.

Association of the protein tyrosine phosphatase non-receptor 22 polymorphism (PTPN22) with endometriosis: a meta-analysis

Objective

To evaluate PTPN22 C1858T polymorphism and the risk of endometriosis.

Methods

A meta-analysis of 10 published case-control studies (from four articles), with a total sample of 971 cases and 1,181 controls, was performed. We estimated risk (odds ratio and 95% confidence intervals) of endometriosis associations with the C1858T polymorphism.

Results

A significant increased risk in all genetic models of the variant T allele with endometriosis (odds ratio: 3.14-5.55; p<0.00001-0.002) was found. The analysis without the study whose controls deviated from the Hardy-Weinberg equilibrium exacerbated these effects in the homozygous and recessive models (odds ratio: 7.19-9.45; p<0.00001-0.0002). In the Italian subgroup, a significant risk association was found in the homozygous and recessive models (odds ratio: 8.72-11.12; p=0.002).

Conclusion

The associations observed between PTPN22 (C1858T) and the risk of endometriosis suggest this polymorphism might be a useful susceptibility marker for this disease.

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.

Involvement of Interferon Regulatory Factor 5 (IRF5) Gene Polymorphisms and Haplotype in Endometriosis-related Infertility

Introduction

The IRF5 gene belongs to a family of transcription factors involved in modulating cell growth, differentiation, apoptosis, and immune system activity. A growing body of evidence indicates that immunological alterations are involved in the pathogenesis of endometriosis, and as a result, polymorphisms in autoimmune-related genes have emerged as possible candidates linked to disease development. Here, we aimed to evaluate a possible association between IRF5 polymorphisms (rs2004640/T>G, rs3807306/G>T, rs10488631/T>C and rs2280714/T>C) and the pathogenesis of endometriosis.

Methods

A case-control study was performed comprising an experimental group of 236 infertile women with endometriosis and a control group of 232 fertile women. IRF5 polymorphisms were identified by real-time PCR using the TaqMan method. Genotype distribution and allele frequency were calculated, and haplotype analysis was performed.

Results

Single-marker analysis revealed that the IRF5 rs10488631 (polymorphic C allele) polymorphism was significantly associated with moderate/severe endometriosis (p = 0.028; OR = 1.79, 95% IC = 1.09–2.94). No association was found with respect to rs2004640, rs3807306 and rs2280714 polymorphisms and the endometriosis group. The combined genotypes of four IRF5 polymorphisms identified the haplotype “GGTT”, which was associated with protection against minimal/mild endometriosis-related infertility (p = 0.003), while the haplotype “GTCT” was associated with a risk of developing moderate/severe endometriosis-related infertility (p = 0.047).

Conclusions

This is the first study to report an association between IRF5 polymorphisms and endometriosis, and the findings suggest that the IRF5 rs10488631 polymorphism and haplotype “GTCT” were involved in the risk of moderate/severe endometriosis development. The haplotype “GGTT” was associated with protection against minimal/mild endometriosis.

Ovarian endometriosis and vitamin D serum levels

AIM

The aim of this study was to assess the vitamin D serum level in women with ovarian endometriosis; specifically, a possible correlation between the dimensions of ovarian endometriomas and vitamin D serum levels was evaluated.

MATERIALS AND METHODS

This was an observational study of childbearing-age women diagnosed with singleton ovarian endometrioma from January 2015 to December 2015. Women diagnosed with multiple ovarian endometriomas or extraovarian endometriosis were excluded.

RESULTS

Forty-nine women constituted the initial study cohort. In these women, the mean (±SD) 25-OH-D3 serum level was 22.0 (±8.9) ng/ml, and 42 of them (85.7%) were diagnosed with hypovitaminosis D. In the "hypovitaminosis D women", the mean (± SD) diameter of ovarian endometriomas was 40.2 ± 22.6 mm, while in the "normal vitamin D serum level women" it was 26.7 ± 12.1 mm (p = 0.1). However, a significant linear correlation between 25-OH-D3 serum level and the diameter of ovarian endometriomas was found (r = -0.3, p = 0.03).

CONCLUSION

We found a relatively high rate of women with ovarian endometriosis and hypovitaminosis D. Interestingly, a significant linear correlation between 25-OH-D3 serum levels and the diameter of ovarian endometrioma emerged.

Serologic markers of autoimmunity in women with recurrent pregnancy loss

PROBLEM

Various autoimmunologic mechanisms have been shown to be involved in recurrent pregnancy loss (RPL). This study aimed to evaluate whether women with RPL have elevated serum levels of common autoimmunologic parameters.

METHOD OF STUDY

Serum levels of antinuclear antibodies (ANAs) were measured in 114 women with RPL, and 107 healthy controls using a qualitative immunometric enzyme immunoassay, serum levels of IgG class autoantibodies against histone, IgG class autoantibodies against nucleosomes, and IgG class autoantibodies against double-stranded (ds) DNA were measured by quantitative enzyme immunoassays.

RESULTS

No differences were ascertained regarding serum levels of ANAs (P=.9), serum levels of antibodies against histones (P=.1), antibodies against nucleosomes (P=.4) and antibodies against dsDNA (P=.6) between women with RPL and healthy controls. No associations were found between serum levels and clinical characteristics of affected women.

CONCLUSION

Our study shows that serologic parameters of autoimmunity are not elevated in women with RPL and are not associated with clinical characteristics of affected women.

Th2 Cells and Th17 Cells in the Development of Endometriosis – Possible Roles of Interleukin-4 and Interleukin-17A

Endometriosis is recognized as an inflammatory disease in which inflammatory cytokines, such as interleukin (IL)-1β and TNFα, play important roles. Immunological factors are also suggested to be involved in the pathogenesis of endometriosis. This review provides comprehensive knowledge about helper T cell (Th cell) and its specific cytokines in endometriosis. A series of our studies demonstrated the presence of Th2 cells and Th17 cells in endometriotic tissues and revealed multiple effects of IL-4 and IL-17A, cytokines secreted from respective Th cells. IL-1β induces secretion of thymic stromal lymphopoietin (TSLP), a regulator for differentiation of inflammatory Th2 cells, in endometriotic stromal cells (ESCs). IL-4 stimulates proliferation of ESCs and production of 3β-hydroxysteroid dehydrogenase Type 2, an enzyme in an estrogen production pathway, in ESCs. IL-17A stimulates IL-8 and Gro-α secretion from ESCs and proliferation of ESCs. IL-17A-induced Gro-α promotes neutrophil migration, which may contribute to the presence of neutrophils in endometriotic tissues. IL-17A also increases secretion of CCL20, a chemokine for Th17 cells, from ESCs, which seems to induce migration of Th17 cells to the endometriotic tissues and enhance the effects of IL-17A further. TNFα in combination with IL-17A synergistically enhances secretion of IL-8 and CCL-20, suggesting cooperation of inflammation and Th17 immune response. These findings suggest that IL-4 and IL-17A promote the development of endometriosis through induction of cell proliferation, inflammation, and estrogen production. It is thus also suggested that IL-4 and IL-17A would be a target of treatment of the disease.

A Western Primer of Chinese Herbal Therapy in Endometriosis and Infertility

Endometriosis is a disease that affects approximately 10% of all reproductive-aged women and the prevalence rises to 20–50% in infertile women. There is growing evidence that medicinal Chinese herbs with pain-alleviating and anti-inflammatory properties may be useful in the treatment of endometriosis and infertility, but the mechanisms of action of these herbs have yet to be investigated. In addition, studies of adequate design, sample size and appropriate control are lacking. Therefore, prospective randomized, controlled studies to evaluate the efficacy, mechanism of action and toxicities of Chinese herbs in the treatment endometriosis and infertility are needed.

Apoptosis and Differential Expression of Apoptosis-Related Proteins in Endometriotic Glandular and Stromal Cells

OBJECTIVE

Apoptosis is an important regulator of eutopic endometrial function. Endometriosis, the growth of endometrial tissue outside the uterus, could result from increased cellular proliferation or decreased apoptosis in response to appropriate stimuli. The objective of this study was to evaluate the rate of apoptosis and the expression of apoptosis-related Bcl-2 and Bax proteins in endometriotic tissues within the glandular and stromal compartments, according to the phase of the menstrual cycle and the stage of disease.

METHODS

Ovarian endometriosis samples were evaluated in 75 women who had surgery at a university hospital. Apoptotic cells were detected with the use of the dUTP nick-end labeling (TUNEL) assay. Bcl-2 and Bax expression were assessed by immunohistochemical techniques.

RESULTS

The percentage of apoptotic cells was significantly higher in endometriotic stromal cells (73.3%) compared with glandular cells (48%; P =.002). In contrast, the expression of the apoptosis-related proteins Bcl-2 and Bax was significantly lower in the endometriotic stroma (17.3% for both) than in the glandular epithelium (38.6% and 41.3%, respectively; P <.004). No significant menstrual cycle phase-dependent changes or endometriosis stage-related changes were observed in TUNEL, Bcl-2, or Bax positivity within ovarian endometriotic tissues.

CONCLUSION

Apoptosis occurs in ovarian endometriotic lesions at significantly higher levels in the stroma than the glandular epithelium. However, Bcl-2 and Bax proteins are distributed preferentially in glandular epithelial cells. The apoptotic rate as well as Bcl-2 and Bax expression in ovarian endometriotic cells were not affected by the stage of endometriosis or the phase of the menstrual cycle.

Prevalence of endometriosis in women with systemic lupus erythematosus and Sjögren's syndrome

Endometriosis is associated with a number of immunologic alterations. It has been suggested that autoimmune disorders could be more frequent in patients with endometriosis. The aim of this study is to ascertain whether the prevalence of two well-known autoimmune diseases [systemic lupus erythematosus (SLE) and Sjögren's syndrome (SS)] is increased in women with endometriosis. The clinical charts of four different populations assisted at the same hospital were manually revised: (i) SLE population ( n = 120), (ii) SS ( n = 22), (iii) endometriosis ( n = 342) and (iv) control population ( n = 501 consecutive unselected asymptomatic women). Among SLE women, the prevalence of endometriosis was 1.67% (2/120), similar to the 4.39% prevalence of the control group (22/501), the OR being 0.37 [95%CI 0.09—1.59]. Among SS women, the prevalence of endometriosis was 9.09 (2/22), also similar to the control group OR 2.17 [95%CI 0.48—9.90]. In the same way, when comparing endometriosis cases with asymptomatic women, similar frequencies of SLE (0.58% and 0.2%) and SS were found (0% and 0%). Women with endometriosis do not have an increased prevalence of SLE or SS. Lupus (2007) 16, 736—740.

Endometriosis and the risks of systemic lupus erythematosus and rheumatoid arthritis in the Nurses' Health Study II

OBJECTIVES

The aetiologies of endometriosis, systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) are all characterised by immune dysfunction. SLE and RA occur more often in women, and reproductive and hormonal factors have been shown to be related to increased risk. However, only one previous study has evaluated the temporal association between endometriosis and SLE or RA. We sought to investigate the association between laparoscopically confirmed endometriosis and subsequently diagnosed SLE and RA.

METHODS

We analysed data from the Nurses' Health Study II (n=114 453 women) over a 22-year follow-up period. Multivariable, time-varying Cox proportional hazards models were used to calculate HRs and 95% CIs for the association between laparoscopically confirmed endometriosis and confirmed incident SLE or RA.

RESULTS

From 1989 to 2011, 103 incident cases of SLE and 390 cases of RA were confirmed. Laparoscopically confirmed endometriosis was significantly associated with subsequent SLE diagnosis (HR=2.03; CI 1.17 to 3.51) and RA diagnosis (HR=1.41; CI 1.05 to 1.89). These associations were robust to adjustment for SLE or RA risk factors and for potential confounders; however, adjustment for hysterectomy and oophorectomy attenuated both relations such that they were no longer significant. No significant differences by infertility status or age (<45 years) were observed.

CONCLUSIONS

Our findings suggest an association between endometriosis and risk of SLE and RA. It remains to be understood whether and how endometriosis itself, or hysterectomy or other factors associated with endometriosis, is related to risk of SLE or RA.

A comprehensive review of pesticides and the immune dysregulation: mechanisms, evidence and consequences

Nowadays, in many communities, there is a growing concern about possible adverse effects of pesticides on human health. Reports indicate that during environmental or occupational exposure, pesticides can exert some intense adverse effects on human health through transient or permanent alteration of the immune system. There is evidence on the relation between pesticide-induced immune alteration and prevalence of diseases associated with alterations of the immune response. In the present study, direct immunotoxicity, endocrine disruption and antigenicity have been introduced as the main mechanisms working with pesticides-induced immune dysregulation. Moreover, the evidence on the relationship between pesticide exposure, dysregulation of the immune system and predisposition to different types of psychiatric disorders, cancers, allergies, autoimmune and infectious diseases are criticized.

STAT4 single nucleotide gene polymorphisms and susceptibility to endometriosis-related infertility

INTRODUCTION

Endometriosis is a multifactorial benign gynecologic disorder, characterized by the ectopic growth of misplaced endometrial cells with complex genetic inheritance and changing of some immune based factors and also shares some autoimmune characteristics. However, it is not clear yet that how and when these immunological factors affect the initiation or progression of the disease. It has been shown that STAT4 is a predisposing gene in the development of some autoimmune diseases.

METHOD

The study group comprised 114 patients with endometriosis and 92 sex-, age-, and ethnicity-matched healthy controls of Iranian ancestry. Four SNPs (rs7574865, rs7601754, rs7582694 and rs11889341) were genotyped using the MGB TaqMan.

RESULTS

A significant association in rs7582694 between C allele (P=0.002, OR=1.986, 95% CI: 1.262-3.126) and endometriosis was found in our study, while the G allele (P=0.002, OR=0.0503, 95% CI: 0.319-0.792) was significantly decreased in the patients population. The GC genotype (P=0.004, OR=2.234, 95% CI: 1.301-4.150) was also significantly overrepresented in the patients with endometriosis, while the frequency of GG genotype was significantly lower in the patient group, compared to the controls (P=0.007, OR=0.457, 95% CI: 0.256-0.813).

CONCLUSIONS

Our results for the first time showed a significant association between rs7582694 alleles and genotypes and susceptibility to endometriosis in a population.

Graves Disease Is Associated With Endometriosis: A 3-Year Population-Based Cross-Sectional Study

The aim of this cross-sectional study was to compare the prevalence of thyroid diseases between women with and without endometriosis.We established the endometriosis group according to diagnosis codes, surgery codes, and gonadotropin-releasing hormone agonist codes using the Korean Health Insurance Review and Assessment Service-National Inpatients Sample (HIRA-NIS) from 2009 to 2011. Four controls were randomly matched to each endometriosis case. Thyroid disease cases were selected using the thyroid disease diagnosis code (E0X).Among the 1,843,451 women sampled, 5615 had endometriosis; 22,460 controls were matched to the endometriosis cases. After adjustment for age and sampling year, Graves disease was associated with endometriosis (odds ratio [OR]: 2.52; 95% CI: 1.30-4.88; P < 0.01), while hypothyroidism was not (OR: 1.17; 95% CI: 0.90-1.52; P = 0.25). Autoimmune hypothyroidism was also not associated with endometriosis (OR: 1.61; 95% CI: 0.88-2.94; P = 0.12).This study revealed an association between Graves disease and endometriosis.

Endometriosis and systemic lupus erythematosus: a population-based case-control study

OBJECTIVE

To investigate the association between endometriosis and systemic lupus erythematosus (SLE) in prospectively collected population-based data.

METHODS

We conducted a case-control study using Swedish registers, identifying female SLE cases from the National Patient Register and female controls sampled from the general population matched on birth year, sex and county during 1964-2011. We identified endometriosis diagnoses from the National Patient Register using ICD codes. We estimated odds ratios and 95% confidence intervals using conditional logistic regression models.

RESULTS

We identified 2834 cases of SLE and 14,164 controls. Seventy-eight cases were diagnosed with endometriosis prior to their SLE diagnosis and 288 controls were diagnosed prior to the index date. We observed a significant association between endometriosis and subsequent SLE with an odds ratio of 1.39 (95% confidence interval = 1.09-1.78). The association was similar when requiring a laparoscopy/laparotomy within six months of the endometriosis diagnosis (odds ratio = 1.33; 95% confidence interval = 0.84-2.12) while the association was stronger when restricted to endometriosis diagnosed at the same time as hysterectomy (odds ratio = 2.26; 95% confidence interval = 1.47-3.64).

CONCLUSIONS

Our findings suggest an association between endometriosis and SLE. Future prospective studies with extended follow-up will be necessary to clarify whether this association is influenced by the timing and severity of endometriosis diagnosis.

Effect of hydroxychloroquine and characterization of autophagy in a mouse model of endometriosis

In endometriosis, the increased survival potential of shed endometrial cells (which normally undergo anoikis) is suggested to promote lesion development. One mechanism that may alter anoikis is autophagy. Using an autophagic flux inhibitor hydroxychloroquine (HCQ), we identified that it reduces the in vitro survival capacity of human endometriotic and endometrial T-HESC cells. We also identified that HCQ could decrease lesion numbers and disrupt lesion histopathology, as well as increase the levels of peritoneal macrophages and the IP-10 (10 kDa interferon-γ-induced protein) chemokine in a mouse model of endometriosis. We noted that RNA levels of a subset of autophagic markers were reduced in lesions relative to uterine horns from endometriosis-induced (untreated) mice. In addition, the RNA levels of autophagic markers were decreased in uterine horns of endometriosis-induced mice compared with those from controls. However, we noted that protein expression of LC3B (microtubule-associated protein 1 light-chain 3β; an autophagic marker) was increased in uterine horns of endometriosis-induced mice compared with uterine horns of controls. By immunohistochemical staining of a human endometriosis-focused tissue microarray, we observed LC3B expression predominantly in epithelial relative to stromal cells in both eutopic and ectopic endometria. Via transmission electron microscopy, cells from eutopic endometria of endometriosis-induced mice contained more lipid droplets (rather than autophagosomes) compared with uterine horns from controls. Collectively, our findings indicate that the autophagic pathway is dysregulated in both ectopic and eutopic endometrium in a murine model of endometriosis and that HCQ has potential as a therapeutic agent for women afflicted with endometriosis.

Endometriosis: bright future for a cloudy past?

New estrogen receptor ligands arrest endometriotic implant survival but spare reproductive cycles in a mouse model of endometriosis, thus forging a path to new treatment options (Zhao et al., this issue).

Association of FCRL3 Genetic Polymorphisms With Endometriosis-Related Infertility Risk: An Independent Study in Han Chinese

The Fc receptor-like 3 (FCRL3) gene was reported to be linked to a variety of autoimmune diseases, including endometriosis-related infertility. However, this linkage has not been studied in Chinese population and there has been no meta-analysis on the interrelationship of FCRL3 gene and endometriosis-related infertility. The aim of the study was to investigate the association between FCRL3 genetic polymorphisms and the risk of endometriosis-related infertility in Han Chinese, and a further meta-analysis was conducted to confirm our results.Four single nucleotide polymorphisms (SNPs) (rs7528684 [FCRL3_3], rs11264799 [FCRL3_4], rs945635 [FCRL3_5], and rs3761959 [FCRL3_6]) on FCRL3 gene were genotyped in a case-control cohort composed of 217 patients suffering from endometriosis-related infertility and 220 healthy controls using cleaved amplification polymorphism sequence-tagged sites (polymerase chain reaction-restriction fragment length polymorphism, PCR-RFLP). Odds ratio (OR) and its 95% confidence interval (CI) was used to evaluate the association quantitatively. Furthermore, a meta-analysis of previous studies including the present study was implemented through Stata 11.0 (Stata Corporation, College Station, TX).We found an approximately 1.4-fold significantly increased frequency of the FCRL3_3 variant in women with endometriosis-related infertility over the controls (OR = 1.41 [95% CI = 1.08-1.84], P = 0.013). However, no significant difference was found between women with endometriosis-related infertility and controls for FCRL3_4, FCRL3_5, and FCRL3_6. Regardless of the symptoms and the revised classification of the American Society of Reproductive Medicine (rASRM) stage of endometriosis, there was a significant association between FCRL3_3 variant and an increased risk of endometriosis-related infertility. Meta-analysis of previous studies combined with the present study further confirmed the association between FCRL3_3 and the risk of endometriosis-related infertility.In summary, the present study suggested that FCRL3_3 variant was associated with an increased risk of endometriosis-related infertility, regardless of symptoms, and rASRM stage of the patients. Meta-analysis of previous studies combined with the present study further confirmed our results. Further large-scale studies in the future are warranted to explore the association between FCRL3 genetic polymorphisms and endometriosis-related infertility, as well as other human diseases, in Asian and other ethnicities.

Endometriosis: a high-risk population for major chronic diseases?

BACKGROUND

Despite an estimated prevalence of 10% in women, the etiology of endometriosis remains poorly understood. Over recent decades, endometriosis has been associated with risk of several chronic diseases, such as cancer, autoimmune diseases, asthma/atopic diseases and cardiovascular diseases. A deeper understanding of these associations is needed as they may provide new leads into the causes or consequences of endometriosis. This review summarizes the available epidemiological findings on the associations between endometriosis and other chronic diseases and discusses hypotheses for underlying mechanisms, potential sources of bias and methodological complexities.

METHODS

We performed a comprehensive search of the PubMed/Medline and ISI Web of Knowledge databases for all studies reporting on the associations between endometriosis and other diseases published in English through to May 2014, using numerous search terms. We additionally examined the reference lists of all identified papers to capture any additional articles that were not identified through computer searches.

RESULTS

We identified 21 studies on the associations between endometriosis and ovarian cancer, 14 for breast cancer, 8 for endometrial cancer, 4 for cervical cancer, 12 for cutaneous melanoma and 3 for non-Hodgkin's lymphoma, as well as 9 on the links between endometriosis and autoimmune diseases, 6 on the links with asthma and atopic diseases, and 4 on the links with cardiovascular diseases. Endometriosis patients were reported to be at higher risk of ovarian and breast cancers, cutaneous melanoma, asthma, and some autoimmune, cardiovascular and atopic diseases, and at decreased risk of cervical cancer.

CONCLUSIONS

Increasing evidence suggests that endometriosis patients are at higher risk of several chronic diseases. Although the underlying mechanisms are not yet understood, the available data to date suggest that endometriosis is not harmless with respects to women's long-term health. If these relationships are confirmed, these findings may have important implications in screening practices and in the management and care of endometriosis patients.

Galectin-1 overexpression in endometriosis and its regulation by neuropeptides (CRH, UCN) indicating its important role in reproduction and inflammation

Endometriosis is an inflammatory disease of women of reproductive age featured by the presence of ectopic endometrium and is strongly related to infertility. Galectins, carbonhydrate-binding proteins, have been found to have pro- or anti-inflammatory roles in the reproductive tract and in pathological conditions concerning infertility. Galectin-1, which is expressed at endometrium and decidua, plays a major role in implantation and trophoblast invasion. Also, the neuropeptides, corticotropin releasing hormone (CRH) and urocortin (UCN) and their receptors are expressed in eutopic and ectopic endometrium showing a differential expression pattern in endometriotic women compared to healthy ones. The aim of this study was to examine the galectin-1 expression in endometriotic lesions and compare its expression in eutopic endometrium of endometriotic and healthy women. Furthermore, we examined the effect of CRH and UCN in galectin-1 expression in Ishikawa cell line and macrophages and investigated the implication of CRHR1 in these responses. Eutopic and ectopic endometrium specimens, Ishikawa cell line and mice macrophages were used. Immunohistochemistry and western blot analysis were performed in order to identify galectin-1 expression in ectopic and eutopic endometrium of women with and without endometriosis and the regulatory effect of CRH and UCN on galectin-1 expression. This study presents for the first time that galectin-1 is overexpressed in endometriotic lesions compared to eutopic endometrium of endometriotic women and is more abundantly expressed in eutopic endometrium of disease women compared to healthy ones. Furthermore, it is shown that CRH and UCN upregulate galectin-1 expression in Ishikawa cell line and macrophages and this effect is mediated through CRHR1. These results suggest that galectin-1 might play an important role in endometriosis pathology and infertility profile of women suffering from endometriosis by being at the same time regulated by CRH and UCN interfering in the immune disequilibrium which characterizes this pathological condition.

T regulatory lymphocytes in patients with endometriosis

The present study aimed to investigate the presence of T regulatory cells (Tregs) in the peripheral blood (PB) and peritoneal fluid (PF) in females with endometriosis. The present study included 42 patients who underwent laparoscopy between 2010 and 2011. Flow cytometry was used to determine the percentage of Tregs in the PF and PB of the patients. No significant difference was observed in the percentage of Tregs in the patients in the endometriosis group compared with those in the control group in the PF (9.1±5.4 vs. 9.1±3.8%) or the PB (6.5±3.2 vs. 6.5±3.7%). However, the percentage of Tregs was found to be higher in the PF compared with the PB in the patients in the endometriosis and control groups, but significance was found only in those in the control group. Furthermore, no significant difference was observed in the Treg concentration in the patients with early stage (I/II) endometriosis compared with those with late stage (III/IV) endometriosis. Moreover, no significant correlation was found between the percentage of Tregs and the white blood cell count, lymphocyte count or CA125 concentration in the patients. These findings suggest that the local host‑defense mechanism is deficient in patients with endometriosis, thus endometriosis should not be treated as an autoimmune condition.

Lipoxin A4 regulates expression of the estrogen receptor and inhibits 17β-estradiol induced p38 mitogen-activated protein kinase phosphorylation in human endometriotic stromal cells

OBJECTIVE

To study the role of lipoxin A4 (LXA4) in endometriosis.

DESIGN

Molecular analysis in human samples and primary human endometriotic stromal cells (ESCs).

SETTING

University hospital.

PATIENT(S)

Forty-nine premenopausal women (30 patients with endometriosis and 19 controls).

INTERVENTION(S)

Normal and ectopic endometrial biopsies obtained during surgery performed during the proliferative phase of the menstrual cycle; ESCs used for in vitro studies.

MAIN OUTCOME MEASURE(S)

Levels of LXA4 measured by enzyme-linked immunosorbent assay (ELISA); mRNA levels of the estrogen receptor (ER), progestogen receptor (PR), tumor necrosis factor α (TNF-α), and interleukin 6 (IL-6) quantified by quantitative reverse-transcription polymerase chain reaction (qRT-PCR); and p38 mitogen-activated protein kinase (p38 MAPK) phosphorylation evaluated by Western blotting.

RESULT(S)

The LXA4 expression level decreased in ectopic tissue as well as ERα and PR, although the expression of ERβ increased in ectopic endometrium compared with the controls. Investigations with correlation analysis revealed the expression of LXA4 was positively correlated with ERα and negatively correlated with ERβ in vivo. Moreover, administering LXA4 could augment ERβ expression in ESCs and inhibit the 17β-estradiol-induced phosphorylation of p38 MAPK very likely through ERβ.

CONCLUSION(S)

Our findings indicate that LXA4 regulates ERβ expression and inhibits 17β-estradiol-induced phosphorylation of p38 MAPK, very likely through ERβ in ESCs.

Prevalence of fibromyalgia and quality of life in women with and without endometriosis

The objectives of the study were to assessed if there is any difference in the prevalence of fibromyalgia and in quality of life (QoL) between women with and without endometriosis. A cross-sectional study was conducted in 2011-2013, involving 257 women with surgically and histopathologically confirmed endometriosis and 253 women with no history of endometriosis and no endometriosis-related symptoms. Women were recruited both at the family planning and endometriosis clinic, Department of Obstetrics and Gynecology, University of Campinas, Brazil. The Short Form 36 questionnaire (SF-36) was used to assess QoL, while the 1990 and 2010 American College of Rheumatology (ACR) criteria were used to evaluate fibromyalgia. According to the 1990 ACR criteria, there were no cases of fibromyalgia in either group. Nevertheless, according to the 2010 ACR criteria, four women, two with endometriosis and two without the disease, were diagnosed with fibromyalgia. Scores were significantly lower in all the domains of the QoL questionnaire for the women with endometriosis compared to those without the disease. This study reports no difference in the prevalence of fibromyalgia between women with and without endometriosis; however QoL was poorer among women with endometriosis when compared to women without the disease.

Looking for celiac disease in Italian women with endometriosis: a case control study

In the last years, a potential link between endometriosis and celiac disease has been hypothesized since these disorders share some similarities, specifically concerning a potential role of oxidative stress, inflammation, and immunological dysfunctions. We investigated the prevalence of celiac disease among Italian women with endometriosis with respect to general population. Consecutive women with a laparoscopic and histological confirmed diagnosis of endometriosis were enrolled; female nurses of our institution, without a known history of endometriosis, were enrolled as controls. IgA endomysial and tissue transglutaminase antibodies measurement and serum total IgA dosage were performed in both groups. An upper digestive endoscopy with an intestinal biopsy was performed in case of antibodies positivity. Presence of infertility, miscarriage, coexistence of other autoimmune diseases, and family history of autoimmune diseases was also investigated in all subjects. Celiac disease was diagnosed in 5 of 223 women with endometriosis and in 2 of 246 controls (2.2% versus 0.8%; P = 0.265). Patients with endometriosis showed a largely higher rate of infertility compared to control group (27.4% versus 2.4%; P < 0.001). Our results confirm that also in Italian population an increased prevalence of celiac disease among patients with endometriosis is found, although this trend does not reach the statistical significance.

The peritoneum--an important factor for pathogenesis and pain generation in endometriosis

Endometriosis (EM) is an oestrogen-dependent disease affecting 10-15 % of women during reproductive age. It is characterised by the presence of endometrial glands, stromal- and smooth muscle-like cells outside of the uterine cavity. Fifty to sixty per cent of women and teenage girls with pelvic pain suffer from EM. EM causes disability and compromises the quality of life in women and young girls significantly. Pain generation in EM is an intricate interplay of several factors such as the endometriotic lesions themselves and the pain-mediating substances, nerve fibres and cytokine-releasing immune cells such as macrophages. These interactions seem to induce a neurogenic inflammatory process. Recently published data demonstrated an increased peptidergic and decreased noradrenergic nerve fibre density in peritoneal lesions. These data could be substantiated by in vitro analyses demonstrating that the peritoneal fluids of patients suffering from EM induced an enhanced sprouting of sensory neurites from chicken dorsal root ganglia and decreased neurite outgrowth from sympathetic ganglia. These findings might be directly involved in the perpetuation of inflammation and pain. Furthermore, the evidence of EM-associated smooth muscle-like cells seems another important factor in pain generation. The peritoneal endometriotic lesion leads to reactions in the surrounding tissue and, therefore, is larger than generally believed. The identification of EM-associated nerve fibres and smooth muscle-like cells fuel discussions on the mechanisms of pain generation in EM, and may present new targets for innovative treatments.

Cytotoxic T-Cells in Peripheral Blood in Women with Endometriosis

Aim: The etiology of endometriosis remains unknown, but increasing evidence suggests that immune regulation may be important. Our study aimed to evaluate peripheral blood lymphocyte subpopulations during the menstrual cycle in women with peritoneal and ovarian endometriosis relative to healthy women. Methods: In this study, 65 women with endometriosis (37 in the follicular phase and 28 in the luteal phase of the menstrual cycle) and 61 healthy women (33 in the follicular phase and 28 in the luteal phase) were enrolled. Flow cytometric analysis measured peripheral blood lymphocyte subpopulations. The serum levels of cortisol were also determined. Results: In healthy controls, we detected an increased concentration of cytotoxic (CD8⁺) T cells and activated (HLA-DR) T cells in the luteal phase compared with the follicular phase of the menstrual cycle (p = 0.020 and p = 0.045), whereas no such fluctuation was detected in endometriosis. However, a marked increase in regulatory T-cell concentration in the luteal phase was detected only in endometriosis patients (p = 0.005). Women with endometriosis had higher levels of serum cortisol (p = 0.022), which correlated with the concentration of regulatory T cells (p = 0.048). Conclusions: Women with endometriosis do not exhibit fluctuations in the concentrations of cytotoxic and activated peripheral blood lymphocytes during the menstrual cycle. The marked fluctuation of regulatory T cells detected in endometriosis could be attributed to altered immune response.

Coincidence of active Crohn's disease and florid endometriosis in the terminal ileum: A case report

Crohn’s disease (CD), a variant of chronic inflammatory bowel disease, frequently affects the terminal ileum and coecal region. The clinical symptoms are often subtle and depend on the inflammatory activity of disease. In women of child-bearing age, florid intestinal endometriosis can simulate CD. Moreover, current pathophysiological concepts include intestinal endometriosis as a putative founder lesion for consecutive CD establishment. The report summarizes clinical and histomorphological data of a 35-year-old woman with the rare coincidence of florid intestinal endometriosis and CD both affecting the terminal ileum. The patient was suffering over 10 years from strong abdominal disorders including constipation, diarrhea, weight loss, and diffuse abdominal pain. In magnetic resonance imaging-Sellink, strong inflammation and intestinal obstruction of the terminal ileum were found. The laparoscopy revealed further evidence for existence of an inflammatory disease like CD, but brownish spots on the peritoneum were found indicative for endometriosis. Surgical resection of the terminal ileum and the coecal segment was performed followed by histopathological investigations. In transmural sections of the terminal ileum, histomorphological features of florid endometriosis intermingled with florid CD was found. The diagnostic findings were substantiated with a panel of immunohistological stainings. In conclusion, the findings demonstrate that florid endometriosis persists in florid CD lesions and the putative link between intestinal endometriosis and CD is more complex than previously assumed.

Low-density lipoproteins oxidation and endometriosis

The etiopathogenesis of endometriosis still remains unknown. Recent data provide new valuable information concerning the role of oxidative stress in the pathophysiology of the disease. It has been proved that levels of different lipid peroxidation end products are increased in both peritoneal fluid (PF) and serum of endometriotic patients. We assessed the concentration of oxidized low-density lipoproteins (oxLDL) in PF of 110 women with different stages of endometriosis and 119 women with serous (n = 78) or dermoid (n = 41) ovarian cysts, as the reference groups. PF oxLDL levels were evaluated by ELISA. We found that concentrations of oxLDL in PF of endometriotic women were significantly higher compared to women with serous but not dermoid ovarian cysts. Interestingly, by analyzing concentrations of oxLDL in women with different stages of the disease, it was noted that they are significantly higher only in the subgroup of patients with stage IV endometriosis as compared to women with ovarian serous cysts. In case of minimal, mild, and moderate disease, PF oxLDL levels were similar to those noted in reference groups. Our results indicate that disrupted oxidative status in the peritoneal cavity of women with endometriosis may play a role in the pathogenesis of advanced stages of the disease.

Prevalence of pain syndromes, mood conditions, and asthma in adolescents and young women with endometriosis

STUDY OBJECTIVE

Adult women with endometriosis are often diagnosed with comorbid pain, mood, and autoimmune conditions. This study aims to describe the occurrence of pain syndromes, mood conditions, and asthma in adolescents and young women with endometriosis evaluated at our medical center.

DESIGN

Retrospective review of medical records.

SETTING

Department of Obstetrics and Gynecology at a tertiary referral center.

PARTICIPANTS

138 adolescents/young women who were less than age 24 years at the time of their initial visit at our medical center, and whose surgical diagnosis of endometriosis was made at our institution or by outside institutions by the age of 21.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Prevalence of comorbid pain syndromes (defined as interstitial cystitis, irritable bowel syndrome, chronic headaches, chronic low back pain, vulvodynia, fibromyalgia, temporomandibular joint disease, and chronic fatigue syndrome), mood conditions (defined as depression and anxiety), and asthma.

RESULTS

Comorbid pain syndromes were found in 77 (56%) women, mood conditions in 66 (48%) women, and asthma in 31 (26%) women. Comparing endometriosis patients with and without comorbid pain syndromes, no differences were found in age at time of diagnosis, endometriosis symptoms, and endometriosis stage. Patients with comorbid pain syndromes were more likely to report mood conditions (62% vs 30% respectively, P < .001) and smoking (31% vs 10% respectively, P = .003), underwent more surgeries for endometriosis (median of 2 [range, 1-7] vs 1 [range, 1-5], P < .005), and were more likely to undergo appendectomy or cholecystectomy (30% vs 13%, P = .02).

CONCLUSIONS

Comorbid pain syndromes, mood conditions and asthma are common in adolescents and young women with endometriosis.

Differential expression of CRH, UCN, CRHR1 and CRHR2 in eutopic and ectopic endometrium of women with endometriosis

Endometriosis is considered as a benign aseptic inflammatory disease, characterised by the presence of ectopic endometrium-like tissue. Its symptoms (mostly pain and infertility) are reported as constant stressors. Corticotropin releasing hormone (CRH) and urocortin (UCN) are neuropeptides, strongly related to stress and inflammation. The effects of CRH and UCN are mediated through CRHR1 and CRHR2 receptors which are implicated in several reproductive functions acting as inflammatory components. However, the involvement of these molecules to endometriosis remains unknown. The aim of this study was to examine the expression of CRHR1 and CRHR2 in endometriotic sites and to compare the expression of CRHR1 and CRHR2 in eutopic endometrium of endometriotic women to that of healthy women. We further compared the expression of CRH, UCN, CRHR1 and CRHR2 in ectopic endometrium to that in eutopic endometrium of women with endometriosis. Endometrial biopsy specimens were taken from healthy women (10 patients) and endometrial and endometriotic biopsy specimens were taken from women with endometriosis (16 patients). Τhe expression of CRH, UCN, CRHR1, and CRHR2 was tested via RT-PCR, immunohistochemistry and Western blotting. This study shows for the first time that CRH and UCN receptor subtypes CRHR1β and CRHR2α are expressed in endometriotic sites and that they are more strongly expressed (p<0.01) in eutopic endometrium of women with endometriosis compared to healthy women endometrium at the mRNA and protein level. CRH, UCN, CRHR1 and CRHR2 mRNA were also more highly expressed in ectopic rather than eutopic endometrium (CRH, UCN, CRHR2α: p<0.01, CRHR1β: p<0.05) and protein (CRH and UCN: p<0.05, CRHR1 and CRHR2: p<0.01) in women with endometriosis. These data indicate that CRH and UCN might play an immunoregulatory role in endometriotic sites by affecting reproductive functions such as decidualization and implantation of women with endometriosis.

Regression of endometrial implants by resveratrol in an experimentally induced endometriosis model in rats

OBJECTIVE

To evaluate the effect of resveratrol on an experimentally induced endometriosis rat model.

STUDY DESIGN

After endometriotic implants were surgically formed, rats were randomly divided into 2 groups as control group (saline treated, n = 6) and resveratrol group (10 mg/kg/d, n = 6). The inflammatory markers and histopathological changes were assessed at the end of the treatment period. Results Our results showed (1) significant reduction in the implant size (P < .0005); (2) significantly decreased levels of vascular endothelial growth factor (VEGF) in the peritoneal fluid and plasma (P < .005); and monocyte chemotactic protein 1 (MCP-1) in the peritoneal fluid (P < .05), (3) highly significant suppression of VEGF expression in the endometriotic tissue (P < .0005); and (4) considerable histological changes in the endometriotic foci following resveratrol treatment.

CONCLUSION

Resveratrol appears to be effective on the development of endometriosis through its antiangiogenic and anti-inflammatory properties. Future studies with different doses of resveratrol might provide more comprehensive results regarding the treatment of endometriosis.

Comparison of Ki-67 proliferative index between eutopic and ectopic endometrium: a case control study

OBJECTIVE

In this study, the Ki-67 proliferative indices among the stages of the endometriosis were compared to clarify whether the proliferation was increased with increasing disease stage.

MATERIALS AND METHODS

Thirty-eight patients who underwent surgery either by laparotomy or by laparoscopy with the diagnosis of endometriosis and 21 patients, as controls, who underwent hysterectomy with the diagnosis of myoma uteri and without any endometrial pathology at our hospital between 2005 and 2007 were studied. Biopsy specimens of endometriotic foci and endometriomas in study group, and eutopic endometrium of hysterectomy specimens of control group were studied.

RESULTS

Fifty-nine patients were divided into Group 1 (21 patients in control), Group 2 (19 patients in stage I and II of endometriosis), and Group 3 (19 patients in stage III and IV). A moderate correlation between the stage of endometriosis and the degree of Ki-67 staining was found. When Ki-67 immunohistochemical staining was considered according to the threshold value for CA-125 (35 U/mL), Ki-67 positivity was increased with the increase in CA-125 value, but this increase was not statistically significant.

CONCLUSION

Endometriosis shows some characteristics of tumors such as high rate of invasion, getting autonomy, and proliferation as the disease progresses with subsequent damage to target organs. When the stage of the disease increases, environment becomes more suitable for increased proliferation and invasion. In this study, the increase in proliferative activity as the severity increases is shown by the increase in Ki-67 index. As more studies are being conducted in this field, pathogenesis will be clarified, which could help in the development of new treatment modalities.

Dairy-food, calcium, magnesium, and vitamin D intake and endometriosis: a prospective cohort study

The etiology of endometriosis is poorly understood, and few modifiable risk factors have been identified. Dairy foods and some nutrients can modulate inflammatory and immune factors, which are altered in women with endometriosis. We investigated whether intake of dairy foods, nutrients concentrated in dairy foods, and predicted plasma 25-hydroxyvitamin D (25(OH)D) levels were associated with incident laparoscopically confirmed endometriosis among 70,556 US women in Nurses' Health Study II. Diet was assessed via food frequency questionnaire. A score for predicted 25(OH)D level was calculated for each participant. During 737,712 person-years of follow-up over a 14-year period (1991-2005), 1,385 cases of incident laparoscopically confirmed endometriosis were reported. Intakes of total and low-fat dairy foods were associated with a lower risk of endometriosis. Women consuming more than 3 servings of total dairy foods per day were 18% less likely to be diagnosed with endometriosis than those reporting 2 servings per day (rate ratio = 0.82, 95% confidence interval: 0.71, 0.95; P(trend) = 0.03). In addition, predicted plasma 25(OH)D level was inversely associated with endometriosis. Women in the highest quintile of predicted vitamin D level had a 24% lower risk of endometriosis than women in the lowest quintile (rate ratio = 0.76, 95% confidence interval: 0.60, 0.97; P(trend) = 0.004). Our findings suggest that greater predicted plasma 25(OH)D levels and higher intake of dairy foods are associated with a decreased risk of endometriosis.

The association of PTPN22 polymorphism with endometriosis: effect of genetic and clinical factors

OBJECTIVE

To investigate the possible effect of clinical and genetic variables on the association between PTPN22 and endometriosis.

METHODS

PTPN22, ACP₁ and p53 codon 72 genetic polymorphisms and duration of previous pharmacological treatment were studied. The study sample consisted of 132 women hospitalized for endometriosis diagnosed by laparoscopic intervention and histologically confirmed: 359 healthy blood donors were studied as controls. PTPN22, ACP1 and p53 codon 72 genotypes were determined by DNA analysis. Discriminant statistical analysis, logistic regression analysis, chi square of independence, power test and linear correlation were performed using SPSS programs.

RESULTS

A significant increase of PTPN22 *T allele in endometriosis is observed in women carrying ACP1*C allele, in women carrying p53 codon 72 *Pro allele and in women with prolonged pharmacological treatment.

CONCLUSIONS

PTPN22 may not be a primary factor in the etiology of endometriosis but may cooperate with clinical and genetic factors influencing susceptibility and clinical course of disease. These new observations point to a multifactorial origin of endometriosis and help to explain the reported differences between human populations concerning the association between PTPN22 and endometriosis.

Neuroimmunomodulatory alterations in non-lesional peritoneum close to peritoneal endometriosis

OBJECTIVES

An imbalance in the ratio of sensory to sympathetic nerve fibre (NF) density in peritoneal endometriotic lesions (pEL) has recently been demonstrated and leads to the assumption that this preponderance of the sensory pro-inflammatory milieu is a major cause of pain in endometriosis. Therefore, the density of sensory and sympathetic NFs was determined in distal unaffected peritoneum of endometriosis patients to be able to detect possible alterations in unaffected peritoneum.

METHODS

In serial pEL sections (n = 40), lesional and matching unaffected peritoneum as well as healthy peritoneum (HP) from patients without endometriosis (n = 15) were immunohistochemically analysed to identify protein gene product 9.5-, substance P- and tyrosine hydroxylase-positive NFs (intact, sensory and sympathetic NFs, respectively). In addition, the amount of immune cell infiltrates and the expression of nerve growth factor (NGF) and interleukin (IL)-1β in nerves of peritoneal endometriotic specimens were compared to those in the HP.

RESULTS

The overall NF density in the non-lesional, unaffected peritoneum of endometriosis patients is significantly reduced in comparison to both HP and pEL, while sensory NFs remain the same; the sympathetic NF density is significantly decreased compared to HP, but is still higher than the density close to the pEL. Immune cell infiltrates as well as NGF and IL-1β expression in nerves is significantly elevated in distal unaffected peritoneum in comparison to HP.

CONCLUSION

The altered NF density in the non-lesional, unaffected peritoneum of endometriosis patients suggests new aspects in the understanding of the development of endometriosis and pain management in endometriosis.

Baboon model for the study of endometriosis

Endometriosis is a benign, estrogen-dependent disease and is now recognized as an enigmatic disease owing to its various clinical manifestations and locations. The lack of a reliable and specific method for the early detection of endometriosis often results in delayed diagnosis. So far, research has born inadequate findings regarding understanding the basic etiology or pathophysiology of endometriosis. Animal models that accurately represent the cellular and molecular changes associated with the initiation and progression of human endometriosis have significant potential to facilitate the development of better methods for the early detection and treatment of endometriosis. A number of animal model systems have been developed for the study of this disease. These models replicate many of the known salient features of human endometriosis. This review provides an insight into the use of the baboon model for studies focused on understanding human endometriosis.

TYK2 rs34536443 polymorphism is associated with a decreased susceptibility to endometriosis-related infertility

INTRODUCTION

Tyrosine kinase 2 gene (TYK2) is part of the janus kinase (JAK) that binds to the type I interferon-α receptor (IFNAR) on the cell surface of IFN-producing cells, and have crucial importance in the etiology of autoimmune and inflammatory diseases. Many polymorphisms of the TYK2 gene have been identified, and recently, a number of case-control studies were conducted to investigate the association of these polymorphisms with autoimmune and inflammatory diseases, with conflicting results. Based on these observations, we hypothesized that the TYK2 polymorphisms (rs34536443, rs2304256, rs280523, rs12720270 and rs12720356) might be involved in the pathogenesis of endometriosis and/or infertility.

METHODS

Genetic association study comprising 275 infertile women with endometriosis, 92 women with idiopathic infertility and 307 fertile women as controls. TYK2 polymorphisms were identified by TaqMan PCR. Genotype distribution, allele frequency and haplotype analysis of the TYK2 polymorphisms were performed. A p-value <0.05 was considered significant.

RESULTS

Single-marker analysis revealed that TYK2 rs34536443 was significantly associated with protection against endometriosis-related infertility, especially in moderate/severe disease (p = 0.002; OR = 0.24, 95% IC = 0.09-0.62). No difference was found considering the infertile group without endometriosis. No associations were found considering rs2304256, rs280523, rs12720270 and rs12720356 either for endometriosis-related infertility group or idiopathic infertility group. Haplotype analysis of five TYK2 polymorphisms identified a haplotype "CTATG" associated with protection against endometriosis-related infertility, especially in moderate/severe disease (p = 0.027).

CONCLUSION

This is the first study to report an association between TYK2 polymorphisms and endometriosis and/or infertility. These findings require replication in other populations but suggest the TYK2 rs34536443 polymorphisms and "CTATG" haplotype can be associated with a decreased susceptibility to endometriosis-related infertility in Brazilian women.

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

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