Endometriosis: New Genetic Approaches and Therapy

Metformin, the Rise of a New Medical Therapy for Endometriosis? A Systematic Review of the Literature

Medical treatments for endometriosis aim to control pain symptoms and stop progression of endometriotic lesions. However, their adverse effects and their contraceptive effect in women who desire pregnancy, limit their long terms use. Although there is only one study investigating the effects of metformin on women with endometriosis, metformin seems to have a unique therapeutic potential. It may be a helpful anti-inflammatory and antiproliferative agent in the treatment of endometriosis. As such metformin may be more beneficial thanks to the lack of serious side effects.

Association of epidermal growth factor receptor (EGFR) gene polymorphisms with endometriosis

AIMS

To investigate the association between polymorphism in the gene encoding the epidermal growth factor receptor (EGFR) and susceptibility to endometriosis among women in southwest China.

METHODS

A case-control study involving 201 endometriosis patients and 237 control women without endometriosis was carried out at West China Second Hospital of Sichuan University from June 2016 to December 2017. Two tag single-nucleotide polymorphisms (SNPs) of EGFR gene, rs11977660 and rs2072454 were selected, and the distribution of genotypes and alleles was compared between the 2 groups using the chi-squared test with 2-sided contingency tables.

RESULTS

Genotype at rs11977660 was significantly associated with endometriosis (P < .05 for genotype and allele). T/T+C/T genotypes were associated with significantly higher risk of developing endometriosis than the C/C genotype (OR 2.129, 95%CI 1.411-3.212). No significant association was found between genotype at rs2072454 and endometriosis.

CONCLUSION

Genotypes with a T nucleotide at rs11977660 may significantly increase risk of endometriosis in Chinese.

Mitochondrial DNA deletions accurately detect endometriosis in symptomatic females of child-bearing age

Aim: Accurate noninvasive diagnostic aids for endometriosis are needed. We evaluated mitochondrial DNA deletions as potential biomarkers for endometriosis. Methods: The diagnostic accuracy of deletions was evaluated by quantitative polymerase chain reaction (QPCR) using well-characterized clinical specimens from all subtypes and stages of endometriosis in a case–control format (n = 182). Results: Deletions (1.2 and 3.7 kb) detected in blood differentiated between endometriosis and controls (area under the curve [AUC] 0.71–0.90). Differences in deletion levels were statistically significant (p < 0.05) for all disease subtypes and stages. Neither deletion was correlated with patient or specimen age or hormone status. The 1.2 kb deletion was not correlated with menstrual stage; the 3.7 kb deletion was significantly correlated between two of the groups. Conclusion: Biomarkers of the mitochondrial genome, including the deletions described here, offer a promising and largely unexplored avenue in the pursuit of diagnostic markers for endometriosis that can be effectively translated to clinical application.

New candidate genes associated to endometriosis

A previous GWAS study performed on Brazilian pooled samples indicated some SNPs (single nucleotide polymorphisms) differentially frequent in infertile patients with endometriosis and controls. Some of them were located in the genes whose biological function suggests that they could be associated with endometriosis pathogenesis; thus, the purpose here was to confirm GWAS findings in a larger group of cases and controls in order to associate the results with the pathogenesis of endometriosis. Then, a genetic association study comprising 394 infertile women with endometriosis and 650 fertile control women was conducted. TaqMan allelic discrimination assays were used to investigate the frequency of three SNPs in the genes KAZN (rs10928050), LAMA5 (rs2427284), and TAC3 (rs733629). The analysis revealed a significant association of KAZN rs10928050 (p = .015) and LAMA5 rs2427284 (p = .0059) SNPs with endometriosis-related infertility, while TAC3 rs733629 showed no difference between cases and controls. As a conclusion, it was possible to observe that individual genotyping of a larger sample of patients and controls confirmed the association among KAZN and LAMA5 with endometriosis-related infertility and revealed new candidate genes contributing to the condition.

Oral contraceptives for pain associated with endometriosis

BACKGROUND

Endometriosis is a common gynaecological condition which affects many women of reproductive age worldwide and is a major cause of pain and infertility. The combined oral contraceptive pill (COCP) is widely used to treat pain occurring as a result of endometriosis, although the evidence for its efficacy is limited.

OBJECTIVES

To determine the effectiveness, safety and cost-effectiveness of oral contraceptive preparations in the treatment of painful symptoms ascribed to the diagnosis of laparoscopically proven endometriosis.

SEARCH METHODS

We searched the following from inception to 19 October 2017: the Cochrane Gynaecology and Fertility Group Specialised Register of Controlled Trials, the Cochrane CENTRAL Register of Studies Online (CRSO), MEDLINE, Embase, PsycINFO, CINAHL (Cumulative Index to Nursing and Allied Health Literature), and the trial registers ClinicalTrials.gov and the World Health Organization Clinical Trials Registry Platform (WHO ICTRP). We also handsearched reference lists of relevant trials and systematic reviews retrieved by the search.

SELECTION CRITERIA

We included randomised controlled trials (RCT) of the use of COCPs in the treatment of women of reproductive age with symptoms ascribed to the diagnosis of endometriosis that had been made visually at a surgical procedure.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study quality and extracted data. One review author was an expert in the content matter. We contacted study authors for additional information. The primary outcome was self-reported pain (dysmenorrhoea) at the end of treatment.

MAIN RESULTS

Five trials (612 women) met the inclusion criteria. Only three trials (404 women) provided data that were suitable for analysis.Combined oral contraceptive pill versus placeboTwo trials compared COCP with a placebo. These studies were at high risk of bias. For GRADE outcomes (self-reported pain (dysmenorrhoea) at the end of treatment), the quality of the evidence very low. Evidence was downgraded for imprecision as it was based on a single, small trial and for the visual analogue scale data there were wide confidence intervals (CIs). There appeared to have been substantial involvement of the pharmaceutical company funding the trials.Treatment with the COCP was associated with an improvement in self-reported pain at the end of treatment as evidenced by a lower score on the Dysmenorrhoea verbal rating scale (scale 0 to 3) compared with placebo (mean difference (MD) -1.30 points, 95% CI -1.84 to -0.76; 1 RCT, 96 women; very low quality evidence), a lower score on the Dysmenorrhoea visual analogue scale (no details of scale) compared with placebo (MD -23.68 points, 95% CI -28.75 to -18.62, 2 RCTs, 327 women; very low quality evidence) and a reduction in menstrual pain from baseline to the end of treatment (MD 2.10 points, 95% CI 1.38 to 2.82; 1 RCT, 169 women; very low quality evidence).Combined oral contraceptive pill versus medical therapiesOne underpowered trial compared the COCP with another medical treatment (goserelin). The study was at high risk of bias; the trial was unblinded and there was insufficient detail to judge allocation concealment and randomisation. For GRADE outcomes (self-reported pain (dysmenorrhoea) at the end of treatment), the quality of the evidence ranged from low to very low.At the end of treatment, the women in the goserelin group were amenorrhoeic and therefore no comparisons could be made between the groups for the primary outcome. At six months' follow-up, there was no clear evidence of a difference between women treated with the COCP and women treated with goserelin for measures of dysmenorrhoea on a visual analogue scale (scale 1 to 10) (MD -0.10, 95% CI -1.28 to 1.08; 1 RCT, 50 women; very low quality evidence) or a verbal rating scale (scale 0 to 3) (MD -0.10, 95% CI -0.99 to 0.79; 1 RCT, 50 women; very low quality evidence). At six months' follow-up, there was no clear evidence of a difference between the COCP and goserelin groups for reporting complete absence of pain as measured by the visual analogue scale (risk ratio (RR) 0.36, 95% CI 0.02 to 8.43; 1 RCT, 50 women; very low quality evidence) or the verbal rating scale (RR 1.00, 95% CI 0.93 to 1.08; 1 RCT, 49 women; low quality evidence).

AUTHORS' CONCLUSIONS

Based on the limited evidence from two trials at high risk of bias and limited data for the prespecified outcomes for this review, there is insufficient evidence to make a judgement on the effectiveness of the COCP compared with placebo and the findings cannot be generalised.Based on the limited evidence from one small trial that was at high risk of bias, there is insufficient evidence to make a judgement on the effectiveness of the COCP compared with other medical treatments. Only one comparison was possible, with the medical intervention being goserelin, and the findings cannot be generalised.Further research is needed to fully evaluate the role of COCPs in managing pain-related symptoms associated with endometriosis. There are other formulations of the combined hormonal contraception such as the transdermal patch, vaginal ring or combined injectable contraceptives which this review did not cover but should be considered in future updates.

Recent Advances in Molecular Genetics of Endometriosis

Endometriosis (MIM 131200) is a prevalent and complex gynecological disease polygenically inherited with multifactorial pathogenesis. It is increasingly recognized as a major women's health issue. Endometriosis is characterized by the presence of endometrial-like tissue in sites outside the uterus, mainly the pelvic peritoneum, ovaries and rectovaginal septum causing severe dysmenorrhoea, dyspareunia, chronic pelvic pain and subfertility. Recent advances in molecular technologies have provided many evidences about the underlying biological events that are likely to be involved in the development of endometriosis. Different chromosomal regions, genes and other molecules, such as microRNAs, have been identified as potentially involved in endometriosis pathogenesis. Moreover, genome-wide analyses of endometriosis have showed novel molecular signatures or individual genes that had not been previously associated with the disease. The goal of these studies is to provide information that might, in turn, lead to new therapies. In this review, some previous studies were updated supporting the polygenic/multifactorial inheritance and the association with malignant neoplasias. We have also emphasized the importance of identifying the causative genes and determining novel diagnostic and predictive biomarkers.

The Early Genes c-fos and c-jun: Potential Targets to Modulate Estrogen Action in Endometriosis?

Endometriosis is a common estrogen-dependent disorder. C-fos and c-jun are early transcription factors probably related to estradiol-dependent cell proliferation. C-fos gene expression is higher in endometriotic implants compared to normal endometrium and the distribution of c-Fos protein is higher in the stroma of endometriotic tissue. C-Jun expression is also more abundant in ectopic endometrial tissue. These findings point to an increased estrogen signaling in endometriosis and suggest that c-fos and c-jun could be potential targets to emerging treatments designed to affect selectively the endometriotic tissue, such as tissue-specific gene therapy.

Molecular pathogenesis of ovarian clear cell carcinoma

Ovarian clear cell carcinoma is a distinct subtype of epithelial ovarian cancer, characterized by an association with endometriosis, glycogen accumulation and resistance to chemotherapy. Key driver events, including ARID1A mutations and HNF1B overexpression, have been recently identified and their functional characterization is ongoing. Additionally, the role of glycogen in promoting the malignant phenotype is coming under scrutiny. Appreciation of the notion that ovarian clear cell carcinoma is essentially an ectopic uterine cancer will hopefully lead to improved animal models of the disease, in turn paving the way for effective treatments.

Endometriosis: a new cellular and molecular genetic approach for understanding the pathogenesis and evolutivity

Endometriosis is a benign disease with high prevalence in women of reproductive age estimated between 10 and 15% and is associated with considerable morbidity. Its etiology and pathogenesis are controversial but it is believed to involve multiple genetic, environmental, immunological, angiogenic, and endocrine processes. Altered expressions of growth factors, cytokines, adhesion molecules, matrix metalloproteinases, and enzymes for estrogen synthesis and metabolism have been frequently observed in this condition. The possibility of genetic basis of endometriosis is demonstrated in studies of familial disease, in which the incidence of endometriosis is higher for first-degree relatives of probands as compared to controls. This review describes mainly the cellular, cytochemical, cytogenetic, and molecular genetic features of endometriotic lesions and cultured endometriotic cells. In attempts to identify candidate gene (s) involved in the pathogenesis of endometriosis, a tissue-based approaches including conventional cytogenetics (RHG-banding), loss of heterozygosity (LOH), and comparative genomic hybridization (CGH) were employed. In addition to the karyotypic anomalies, consistent chromosome instability was confirmed by CGH and fluorescence in situ hybridization (FISH). The nature and significance of the molecular genetic aberrations in relation to the locations and function of oncogenes and tumor suppressor genes will be discussed. At last, a possible pathogenic role of embryonic duct remnants was observed in seven female fetal reproductive tract in endometriosis and may induce a discussion about the beginning of ovarian tumors and malignant proliferations.

Polymorphic variants of CYP17 and CYP19A and risk of infertility in endometriosis

OBJECTIVE

Endometriosis is recognized as an estrogen-dependent disease. There are conflicting data demonstrating single nuclear polymorphisms (SNPs) of CYP17 and CYP19 steroidogenic genes as related to endometriosis risk. We assessed the CYP17 5'-untranslated region -34 A/G (rs743572) and CYP19 Ex10 + C1558T (rs10046) SNPs in stage I-II endometriosis.

DESIGN

Case-control study.

SETTING

Division of reproduction at a university department in Poland.

POPULATION

A total of 115 women with diagnosed stage I-II endometriosis according to the revised American Society for Reproductive Medicine (rASRM) classification and 197 fertile women as controls.

METHODS

The SNPs CYP17 -34 A/G and CYP19 Ex10 + C1558T were identified by high-resolution melting curve analysis.

MAIN OUTCOME MEASURES

Genotype prevalence and odds ratio for recessive and dominant genetic model for CYP17 and CYP19 SNPs.

RESULTS

We observed a significantly increased CYP17 GG and GA genotype frequency in women diagnosed with rASRM stage I-II endometriosis compared with fertile women (OR = 2.4; 95% CI 1.4-4.2, p = 0.002). We also found a significantly increased CYP17 G allele frequency in cases compared with controls (OR = 1.6; 95% CI 1.2-2.2, p = 0.004). There were no significant differences in the distribution of the CYP17 GG genotype and CYP19 Ex10 + C1558T polymorphism between women diagnosed with rASRM stage I-II endometriosis and controls.

CONCLUSION

The CYP17 -34 G variant, previously associated with increased 17β-estradiol production, displayed a contribution to stage I-II endometriosis in women from a Polish population. Increased 17β-estradiol concentration in carriers of the CYP17 -34 G variant might contribute to endometriosis and associated pathological processes.

Advances in endometriosis treatment

Endometriosis is a common problem characterized by abdominal pain, back pain, pain with intercourse, dysfunctional uterine bleeding, and infertility. The cause of endometriosis is not well understood, but advances in treatment have been made. Primary care clinicians are uniquely situated to improve patient outcomes by making informed treatment decisions.

Aberrant histone acetylation and methylation levels in woman with endometriosis

OBJECTIVE

To investigate the alterations in histone modifications in woman with endometriosis.

METHODS

Global histone H3/H4 acetylation and H3K4/H3K9 methylation in eutopic and ectopic endometrium from 15 endometriosis patients were assayed using the EpiQuik global histone H3/H4 acetylation and H3K4/H3K9 methylation assay kits. Quantitative real-time reverse transcriptase-polymerase chain reaction was applied to measure mRNA levels of 12 members of histone-related chromatin modifier genes.

RESULTS

Histone H4 hypoacetylation was detected both in eutopic and ectopic endometrium. There were no difference between patients with endometriosis and controls on global levels of H3 acetylation. Furthermore, global histone H3K4 hypomethylation and H3K9 hypomethylation were detected both in ectopic and eutopic endometrium (p < 0.001), and in ectopic endometrium (p < 0.001), respectively. SIRT1 mRNA level was significantly decreased in eutopic endometrium, while mRNA levels of HDAC1, SUV39H1, SUV39H2 and G9a were significantly downregulated in ectopic endometrium. HDAC2 mRNA level was significantly increased in eutopic endometrium. PCAF mRNA level was significantly increased in ectopic endometrium.

CONCLUSIONS

Aberrant histone modification may play an important role in the pathogenesis of endometriosis.

Polymorphic variants of DNMT3A and the risk of endometriosis

OBJECTIVE

Overexpression of DNA methyltransferase 3A (DNMT3A) and aberrant methylation of various genes in eutopic endometrium have been demonstrated in women with endometriosis. We aimed to study whether DNMT3A polymorphisms could be a genetic risk factor for endometriosis and endometriosis-related infertility.

STUDY DESIGN

We studied 5 SNPs (rs2289195, rs7590760, rs13401241, rs749131 and rs1550117) located in the DNMT3A gene in 357 women with endometriosis and 640 controls.

RESULTS

We did not observe significant differences between genotype and allele frequencies of rs2289195, rs7590760, rs13401241, rs749131 and rs1550117 SNPs in women with endometriosis, endometriosis-related infertility, and controls. The lowest p values of the trend test were observed for DNMT3A rs1550117 in endometriosis and endometriosis-related infertility (p(trend)=0.049 and p(trend)=0.055, respectively).

CONCLUSIONS

Our results did not supply evidence for the contribution of SNPs located in DNMT3A to either endometriosis or endometriosis-related infertility.

XRCC1 399 Arg-related genotype and allele, but not XRCC1 His107Arg, XRCC1 Trp194Arg, KCNQ2, AT1R, and hOGG1 polymorphisms, are associated with higher susceptibility of endometriosis

X-ray repair cross-complementing group 1 (XRCC1) and human 8-oxoguanine glycosylase 1 (hOGG1) play important roles in base excision repair. KCNQ genes comprising voltage-gated ion-channels related with cell stability. Angiotensin II type 1 receptor (AT1R) is related with angiogenesis, which influence endometriosis growth, invasion and regression. We aimed to investigate whether these polymorphisms were associated with endometriosis susceptibility. Women were divided [ 1 ]: endometriosis (n = 136 [ 2 ]); non-endometriosis groups (n = 112). XRCC1 (codon 107, 194, 399), hOGG1, KCNQ2, AT1R polymorphisms were amplified by PCR and detected by electrophoresis after restriction enzyme (RsaI, HpaII, MspI, Fnu4HI, Ava II, Dde I) digestions. Genotypes and allelic frequencies in both groups were compared. Proportions of XRCC1 Arg399Gln*GG/GA/AA and G/A allele between both groups were [ 1 ]: 41.9/53.7/4.4% and 68.8/31.2% [ 2 ]; 30.4/54.5/15.1% and 57.6/42.4% (p < 0.05). Other 5 polymorphisms (XRCC1 codon 107 and 194, hOGG1, KCNQ2, and AT1R) between both groups were non-significantly different. Proportions of XRCC1 107*AA/AG/GG and XRCC1 194*TT/TC/CC between both groups were [ 1 ]: 3.7/27.2/69.1% and 5.8/34.6/59.6% [ 2 ]; 2.6/21.4/75.8% and 11.6/37.5/50.9%. HOGG1*CC/CG/GG, KCNQ2*AA/AC/CCC and AT1R*AA/AC/CC were [ 1 ]: 14.8/42.6/42.6, 14/41.9/44.1 and 92.6/7.4/0% [ 2 ]; 11.6/50/38.4, 17/50/33 and 100/0/0%. We concluded that XRCC1 399 Arg-related genotype and allele are correlated with higher susceptibility to endometriosis, which suggested its association with endometriosis pathogenesis. XRCC1 107 and 194, hOGG1, KCNQ2, and AT1R are not associated with endometriosis susceptibility.

Expression of HOXA11 in the mid-luteal endometrium from women with endometriosis-associated infertility

BACKGROUND

A decrease in HOXA11 expression in eutopic mid-secretory endometrium has been found in women with endometriosis-associated infertility.

METHODS

Using Real-time quantitative PCR (RQ-PCR) and western blotting analysis we studied the HOXA11 transcript and protein levels in mid-luteal eutopic endometrium from eighteen infertile women with minimal endometriosis, sixteen healthy fertile women and sixteen infertile women with fallopian tubal occlusion from the Polish population. We also evaluated transcript levels of DNA methyltransferases DNMT1, DNMT3A and DNMT3B in these groups of women.

RESULTS

There were significantly lower levels of HOXA11 transcripts (p = 0.003, p = 0.041) and protein (p = 0.004, p = 0.001) in women with endometriosis as compared to fertile women and infertile women with tubal occlusion. Moreover, we found significantly higher methylation levels of the CpG region in the first exon of HOXA11 in infertile women with endometriosis compared with fertile women (p < 0.001) and infertile women with tubal occlusion (p < 0.001). We also observed significantly increased levels of DNMT3A transcript in women with endometriosis than fertile women (p = 0.044) and infertile women with tubal occlusion (p = 0.047). However, we did not observe significant differences in DNMT1 and DNMT3B transcript levels between these investigated groups of women.

CONCLUSIONS

We confirmed that reduced HOXA11 expression may contribute to endometriosis-associated infertility. Moreover, we found that DNA hypermethylation can be one of the possible molecular mechanisms causing a decrease in HOXA11 expression in the eutopic mid-secretory endometrium in infertile women with endometriosis.

The management of stage III and IV endometriosis

The clinical manifestations of severe endometriosis are variable and unpredictable in both presentation and course. There are also a proportion of women with severe endometriosis who remain asymptomatic. The treatment of severe endometriosis must be individualised, taking into account the impact of the disease and treatment on pain, fertility and quality of life. Surgery is usually required and multiple organs are sometimes involved. Therefore, if endometriosis is severe, referral to a center with the expertise to offer all available treatments in a multidisciplinary team, including advanced laparoscopic surgery and laparotomy, is strongly recommended. It is also important to involve the woman in all decisions, to be flexible in diagnostic and therapeutic thinking, to maintain a good relationship with the woman and to seek advice where appropriate.

Aberrant DNA methylation status of endometriosis: epigenetics as the pathogenesis, biomarker and therapeutic target

Endometriosis, a common, benign, estrogen-dependent disease affecting 3-10% of women of reproductive age, is characterized by the ectopic growth of endometrial tissue that is found primarily in the peritoneum, ovaries and rectovaginal septum. Recently, endometriosis has been alternatively described as an immune disease, a genetic disease and a disease caused by exposure to environmental factors, in addition to its usual description as a hormonal disease. In addition, accumulating evidence suggests that various epigenetic aberrations play definite roles in the pathogenesis of endometriosis. Epigenetic alterations reported to date in endometriosis include the genomic DNA methylation of progesterone receptor-B, E-cadherin, homeobox A10, estrogen receptor-β, steroidogenic factor-1 and aromatase. Aberrant expression of DNA methyltransferases, which attach a methyl group to the 5-carbon position of cytosine bases in the CpG island of the promoter region and silence the corresponding gene expression, has also been demonstrated in endometriosis. This review summarizes the recent studies on the aberrant DNA methylation status and aberrant expression of DNA methyltransferases, which regulate DNA methylation, in endometriosis. We also discuss the recent information on the diagnostic and therapeutic implications of epigenetic alterations occurring in endometriosis.

Photodiagnosis and photodynamic therapy of endometriotic epithelial cells using 5-aminolevulinic acid and steroids

BACKGROUND

The photodynamic diagnosis and therapy represent relatively new methods used, i.a., in the detection of some preneoplastic and neoplastic conditions. They are based on selective accumulation of photosensitizers in the altered cells, which can be identified by fluorescence of the sensitizers and, using light of an appropriate wavelength, can be eliminated. Currently, investigations continue on application of the methods in diagnosis and therapy of endometriosis, one of the most prevalent causes of a reduced fertility in women.

METHODS

In this study protoporphyrin IX, a photosensitizer derived from 5-aminolevulinic acid, was used to locate and destroy endometrial epithelium. Material for the investigations involved primary epithelial cells, isolated from 15 normal endometria and 15 ovarian endometriotic epithelia. Taking into account the cyclical hormonal alterations, which affect endometrial cells in individual phases of the menstrual cycle, experiments were conducted on accumulation of the photosensitizer and photodestruction of the cells preceded by their hormonal stimulation (17β-estradiol and progesterone).

RESULTS AND CONCLUSION

It was found that following 48 h stimulation with 17β-estradiol and/or progesterone a significantly augmented synthesis of protoporphyrin IX can be obtained in cells of endometrial epithelium as compared to the normal epithelium. Moreover, the endometriotic epithelial cells were most effectively eliminated following 48 h prestimulation with progesteron alone. The obtained result permits to assume that photodynamic diagnosis and photodynamic therapy of endometrial epithelium should be performed in the secretory phase of endometrium in order to optimise their results.

Endometrioid ovarian cancer and endometriotic cells exhibit the same alteration in the expression of interleukin-1 receptor II: to a link between endometriosis and endometrioid ovarian cancer

AIM

Endometrioid carcinoma of the ovary is the third most common type of epithelial ovarian cancer. Endometrioid tumors as well as endometriotic implants are characterized by the presence of epithelial cells, stromal cells, or a combination of booth, that resemble the endometrial cells, suggesting a possible endometrial origin of these tumors. Th1 cytokines including interleukin (IL)-1 have been reported to be involved in both endometriosis and ovarian carcinogenesis. We assessed the expression of receptors of IL-1 (IL-1RI and IL-1RII, the signal transducer and the specific inhibitor of IL-1, respectively) in cells of the most common subtypes of ovarian cancer compared to endometrial cells.

MATERIAL & METHODS

IL1-Rs expression was analyzed at the levels of the protein and mRNA using immunofluorescent and real-time polymerase chain reaction methods, respectively.

RESULTS

We showed that endometrioid cells exhibit a specific decrease of IL-1RII expression, whereas IL-1RI was constantly expressed in all studied cell subtypes.

CONCLUSION

As already reported in endometriotic cells, endometrioid ovarian cancer cells exhibit the same alteration in the expression of IL-1RII, a key protector against tumorigenic effects of IL-1. Our findings highlight a common signature between endometrioid ovarian cancer and implants of endometriosis, which needs to be fully explored.

Genetics and genomics of endometriosis

Endometriosis is a common cause of morbidity in women with an unknown etiology. Studies have demonstrated the familial nature of endometriosis and suggest that inheritance occurs in a polygenic/multifactorial fashion. Studies have attempted to define the gene or genes responsible for endometriosis through association or linkage studies with candidate genes or DNA mapping technology. A number of genomics studies have demonstrated significant alterations in gene expression in endometriosis. A more thorough understanding of the genetics and genomics of endometriosis will facilitate understanding the basic biology of the disease and open new inroads to diagnosis and treatment of this enigmatic condition.

Endometriosis-associated ovarian cancer: A ten-year cohort study of women living in the Estrie Region of Quebec, Canada

Objectives

Endometriosis has been believed to increase the risk of developing ovarian cancer, but recent data supporting this hypothesis are lacking. The aim of this study was to verify whether the incidence of endometriosis, ovarian cancer and the both increased during the last 10 years among women living in the Estrie region of Quebec.

Methods

We collected data of women diagnosed with endometriosis, ovarian cancer or both, between 1997 and 2006, from a population living in the Estrie region of Quebec. We performed this retrospective cross-sectional study from the CIRESSS (Centre Informatisé de Recherche Évaluative en Services et Soins de Santé) system, the database of the CHUS (Centre Hospitalier Universitaire of Sherbrooke), Sherbrooke, Canada.

Results

Among the 2854 identified patients, 2521 had endometriosis, 292 patients had ovarian cancer and 41 patients had both ovarian cancer and endometriosis. We showed a constant increase in the number of ovarian cancer (OC) between 1997 and 2006 (r² = 0.557, P = 0.013), which is not the case for endometriosis (ENDO) or endometriosis-associated ovarian cancer (EAOC). The mean age ± SD was 40.0 ± 9.9 and 53.9 ± 11.4 for patients having ENDO and OC, respectively. Mean age of women with EAOC was 48.3 ± 10.8, suggesting an early onset of ovarian cancer in women having endometriosis of about 5.5 years average, P = 0.003. Women with ENDO were at increased risk for developing OC (Rate Ratio [RR] = 1.6; 95% Confidence Interval [CI] = 1.12-2.09). Pathological analyses showed the predominance of endometrioid type (24.4%) and clear-cell type (21.9%) types in EAOC compared to OC, P = 0.0070 and 0.0029, respectively. However, the serous type is the most widespread in OC (44.5%) in comparison to EAOC (19.51%), P = 0.0023.

Conclusion

Our findings highlight that the number of cases of ovarian cancer is constantly increasing in the last ten years and that endometriosis represents a serious risk factor which accelerates its apparition by about 5.5 years.

Rectovaginal endometriosis – a frequently missed diagnosis

To assess the proportion of women found to have rectovaginal endometriosis who underwent a previous laparoscopy with negative findings, a 5-year retrospective observational study was carried out at the University Hospital of Wales, Cardiff UK, from 2001 to 2005. A total of 61 cases with potential symptoms of rectovaginal endometriosis who underwent laparoscopy were identified. Rectovaginal endometriosis was identified in 16 of these cases. Previous laparoscopy was carried out in 33 of these 61 cases. In the group of women found to have rectovaginal endometriosis, 14 cases of rectovaginal endometriosis were not identified by pre-referral laparoscopy. This study supports the anecdotal idea that rectovaginal endometriosis is an often missed diagnosis at the time of laparoscopy. Diagnostic laparoscopy by generalist gynaecologists frequently fails to diagnose rectovaginal endometriosis. The routine use of rectal probes at laparoscopy is recommended to increase diagnostic accuracy.

Nuclear factor κB pathway and interleukin-6 are affected in eutopic endometrium of women with endometriosis

In order to investigate the role of the nuclear factor κB (NFKB) pathway on gene expression in the eutopic endometrium in endometriosis, and in particular of interleukin-6 (IL6), we evaluated RELA, IκB kinase (CHUK), NFKBIA and IL6 expressions and NFKB DNA binding in eutopic endometrium from women with endometriosis. Eutopic endometrium was obtained from 37 women with endometriosis and 42 fertile women during laparoscopy. We analysed RELA, CHUK, NFKBIA and IL6 mRNA levels (RT-PCR); RELA, CHUK and NFKBIA proteins and p-NFKBIA/NFKBIA ratio (western blot); and NFKB binding (DNA shift assay) and IL6 concentration (ELISA) in endometrial explants. Our results indicate that mRNA and cytoplasmic proteins of RELA and CHUK exhibit constant levels in normal endometrium during the menstrual cycle. A dramatic increase (P<0.05) in NFKBIA mRNA expression, RELA nuclear presence and the mRNA and the protein of IL6 during late secretory phase was also observed in this tissue. By contrast, in eutopic endometrium from endometriosis patients, a decrease (P<0.05) in IL6 mRNA and protein (61%), NFKBIA mRNA (46%), p-NFKBIA/NFKBIA ratio (42%), RELA nuclear stromal (68%) and CHUK (48%) proteins were found exclusively during the late secretory phase compared with normal endometrium. In conclusion, the canonical activation of NFKB pathway is deregulated and may have reduced transcriptional function affecting NFKBIA and IL6 expression, genes related local proinflammatory processes. These molecular alterations observed during the late secretory phase in eutopic endometrium from endometriosis patients constitute a NFKB system dysfunction, suggesting that NFKB could be an important factor in endometriosis aetiology.

Recognising, understanding and managing endometriosis

Endometriosis is defined as the presence of tissue lesions or nodules, histologically similar to the endometrium, at sites outside the uterus. It is a highly variable condition that has a wide spectrum of symptoms. The aetiology of endometriosis is probably multifactorial, with a strong familial component recognised. Women with endometriosis have multiple disturbances of function in the eutopic endometrium that women without the disease do not have. A firm diagnosis of endometriosis is rarely possible in general practice. The 'gold standard' for the diagnosis of pelvic endometriosis is currently a diagnostic laparoscopy.

Increased frequency of human leukocyte antigen-E inhibitory receptor CD94/NKG2A-expressing peritoneal natural killer cells in patients with endometriosis

OBJECTIVE

To analyze the frequency of peritoneal natural killer (NK) cells expressing the human leukocyte antigen (HLA)-E receptor CD94/NKG2A in patients with endometriosis.

DESIGN

Case-control study.

SETTING

University hospital.

PATIENT(S)

Stage III and stage IV endometriosis, according to the revised American Society for Reproductive Medicine classification, was laparoscopically and histologically confirmed in 11 and 9 patients, respectively; 13 subjects without endometriosis were selected for the control group.

INTERVENTION(S)

Collection of peripheral venous blood, peritoneal fluid, endometriotic tissue, and normal endometrium in subjects undergoing laparoscopy.

MAIN OUTCOME MEASURE(S)

Surface expression levels of CD94/NKG2A and CD94/NKG2C were detected by three-color cytofluorometric analysis. Semiquantitative HLA-E messenger RNA expression analysis was performed in endometriotic lesions and in eutopic endometrium. NK cell-mediated cytotoxic activity toward HLA-E positive target, DT360 cell line, was also determined.

RESULT(S)

In women with endometriosis, the percentage of CD94/NKG2A-positive peritoneal NK cells was significantly higher than in the control group. The CD94/NKG2A ligand, HLA-E, was detected at high levels in endometriotic tissue as messenger RNA transcript. Target cells bearing HLA-E were resistant to NK cell-mediated lysis in a CD94/NKG2A-dependent manner.

CONCLUSION(S)

Increased expression of CD94/NKG2A in peritoneal NK cells may mediate the resistance of endometriotic tissue to NK cell-mediated lysis, thus contributing to the progression of the disease.

Abnormal interleukin 1 receptor types I and II gene expression in eutopic and ectopic endometrial tissues of women with endometriosis

Interleukin-1 (IL1) is believed to play a central role in the immuno-inflammatory process associated with endometriosis. IL1 triggers cell activation via its receptor type I (IL1R1), but its receptor type II (IL1R2) is known instead as a scavenger that buffers the cytokine's effects. Our previous studies have shown increased expression of IL1R1 in active endometriotic implants compared to normal and endometriosis women-derived endometrial tissues, and a simultaneous decrease in IL1R2 expression at the protein level. In the present study, in situ hybridization demonstrated a noticeable decrease in IL1R2 mRNA hybridization score in eutopic and matched ectopic endometrial tissues of women with endometriosis compared to normal women in the stroma (P<0.001 and P<0.001, respectively) and the epithelium (P<0.01 and P<0.05, respectively), whereas IL1R1 mRNA hybridization score was higher only in the ectopic implants, with a statistically significant difference in the stroma (P<0.05). This was corroborated by RT-PCR analysis of IL1R1 and IL1R2 mRNAs in ectopic (P<0.05 and P<0.05, respectively) and matched eutopic (P=0.22 and P<0.05, respectively) endometrial tissues from women with endometriosis compared to endometrial tissues from normal women. The decrease in IL1R2 mRNA levels in eutopic endometrial tissue of endometriosis women, and the concomitant increase in IL1R1 mRNA levels in ectopic implants, reveal a profound defect in IL1R 1 and IL1R2 gene expression which may accentuate the capability of this tissue to respond to IL1 and favor its ectopic growth.

Future of endometriosis research

In women of reproductive age, health economic costs are estimated to be considerably higher for endometriosis than for conditions such as Crohn's disease, migraine and hypertension, and similar to the cost of diabetes. However, more awareness of endometriosis among patients and politicians is needed to create a better climate for research funding in the area of endometriosis in particular, and women's health in general. Recent collaboration between patients, physicians and politicians in the EU has shown that such efforts can be successful. Many arguments exist to organize the clinical care for women with advanced endometriosis in centers of excellence, but continuing education of primary-care physicians also remains a priority. New molecular techniques are resulting in new hormonal and nonhormonal targets for the noninvasive diagnosis and treatment of endometriosis. A future diagnostic serum assay might contain various elements from inflammatory serum markers to genetic/microarray/proteomics markers, owing to the multifactorial features of endometriosis.

Increased expression of interleukin-1 receptor type 1 in active endometriotic lesions

The establishment and progression of ectopic endometrial implants are dependent upon their interaction with and responsiveness to the stimuli present in their new environment. According to our and other previous studies, immune cells-derived cytokines, such as IL-1, may alone or in concert with estrogens, enhance the capability of ectopic endometrial cells to implant and develop into the host tissue. In the present study, immunohistochemical and dual immunofluorescence analyses showed that the functional signaling interleukin-1 receptor type 1 (IL-1RI) is expressed in endometriotic tissue, particularly in the glands, and identified endothelial cells, macrophages, and T-lymphocytes as cells having marked expression of IL-1RI. The highest concentrations of IL-1RI protein in endometriotic tissue, as evaluated using histological score (HSCORE) and measured by ELISA, were found in red endometriotic lesions as compared with typical black-blue or white lesions. Western blotting showed a significant increase in the levels of the 50 kDa band, whose apparent molecular weight corresponds to the soluble form of IL-1RI. RT-PCR analysis of IL-1 mRNA levels showed a pattern of expression comparable to that of the protein. Interestingly, IL-1RI expression was more significant in the proliferative than in the secretory phase of the menstrual cycle. Marked expression of IL-1RI, the functional signaling receptor that mediates cell activation by IL-1, in red endometriotic implants, which are highly vascularized and represent the earliest and most active forms of the disease, point to a higher cell receptivity for IL-1 in these lesions, a relationship with the activity of the disease and a possible involvement in the early steps of endometriotic tissue growth and development.

Oral contraceptives for pain associated with endometriosis

BACKGROUND

Endometriosis is a common gynaecological condition which affects many women of reproductive age worldwide and is a major cause of pain and infertility. The modern oral contraceptive pill is widely used to treat pain occurring as a result of endometriosis, although the evidence for its efficacy is limited.

OBJECTIVES

To assess the effects of the oral contraceptive pill (OCP) in comparison to other treatments for painful symptoms of endometriosis in women of reproductive age.

SEARCH STRATEGY

We searched the Menstrual Disorders and Subfertility Group Specialised Register of controlled trials; Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 3, 2006); MEDLINE (January 1966 to September 2006); EMBASE (1980 to September 2006); National Research Register; and reference lists of articles.

SELECTION CRITERIA

All truly randomised controlled trials of the use of oral contraceptive pills in the treatment of women of reproductive age with symptoms ascribed to the diagnosis of endometriosis and made visually at surgical procedure were included.

DATA COLLECTION AND ANALYSIS

Study quality assessment and data extraction were carried out independently by two review authors. One of the assessors was an expert in the content matter. We contacted study authors for additional information.

MAIN RESULTS

Only one study met the inclusion criteria, in which a total of 57 women were allocated to two groups to compare an OCP to a GnRH analogue. Methods of randomisation and allocation concealment were unclear and the study was acknowledged by its authors to be underpowered. Women in the GnRH analogue group became amenorrhoeic during the treatment period of six months, whilst women in the OCP group reported a decrease in dysmenorrhoea. No evidence of a significant difference between the two groups was observed in terms of dysmenorrhoea at six months follow up after stopping treatment (OR 0.48; 95% CI 0.08 to 2.90). Some evidence for a decrease in dyspareunia was found at the end of treatment in women in the GnRH analogue group, although no evidence of a significant difference in dyspareunia was observed at the end of the six months follow up (OR 4.87; 95% CI 0.96 to 24.65).

AUTHORS' CONCLUSIONS

The limited data we found available suggests that this is no evidence of a difference in outcomes between the the oral contraceptive pill (OCP) studied and GnRH analogue was as effective as a GnRH analogue in treating for endometriosis-associated painful symptoms of endometriosis. However, the lack of studies with larger sample sizes, or focusing on other comparable treatments is concerning and further research is needed to fully evaluate fully the role of OCPs oral contraceptive pills in managing symptoms associated with ement of endometriosis.

Imbalance in the expression of the activating type I and the inhibitory type II interleukin 1 receptors in endometriosis

BACKGROUND

The ectopic establishment and progression of endometrial tissue is dependent upon its interaction with and responsiveness to the stimuli present in its new environment. Immune cell-derived cytokines, such as interleukin 1 (IL1), may alone or in concert with estrogens enhance the capability of ectopic endometrial cells to implant and develop into the host tissue. The objective of this study was to further evaluate the expression and significance of IL1 receptor type I (IL1R1), the signalling receptor that mediates cell activation by IL1, and IL1 receptor type II (IL1R2), a potent and specific down-regulator of IL1 action, in normal compared to endometriotic/endometrial tissues.

METHODS

Techniques included immunohistochemistry, immunofluorescent staining, ELISA, western blotting and endometriotic cell culture transfection.

RESULTS

Our study showed an imbalance in the expression of IL1R1 and IL1R2 in eutopic, and particularly in ectopic, endometrial tissues of women with endometriosis. Actually, a decreased IL1R2 expression is predominant in the eutopic and ectopic endometrium of women with endometriosis when compared with normal women, whereas a concomitant increase in IL1R1 expression occurs in ectopic endometrial tissue in comparison to eutopic endometrial tissue of normal or endometriotic women, particularly in the initial and most active implants. Transfection of endometriotic cells with a cDNA coding for IL1R2 resulted in a significant decrease in IL1-induced secretion of vascular endothelial cell growth factor and monocyte chemotactic protein 1.

CONCLUSIONS

IL1R1/IL1R2 imbalance may amplify endometrial cell responsiveness to IL1 and represent a key mechanism underlying the ability of these cells to implant and develop into host tissues.

Endometriosis: the way forward

Endometriosis, a common cause of morbidity, affects 10% of women of reproductive age. In this review we focus on the new developments in pathogenesis, diagnosis and treatment options, reviewing the literature published about this enigmatic disorder over the past three years. More specifically, new theories of the pathogenesis of the syndrome of Sampson and Cullen are discussed. The new era of genomics may characterize endometriosis and transform clinical management of the disease. Literature suggesting that endometriosis may have an environmental origin is reviewed. New approaches to medical therapy of endometriosis have been developed, including the levonorgestrel-releasing intrauterine device, aromatase inhibitors, immunomodulatory drugs, angiogenesis inhibitors, selective estrogen and progesterone receptor modulators, and statins. Subfertility is another well-known result of endometriosis and often complex decisions must be made regarding management of the endometriosis patient who wishes to conceive. Laparoscopic surgery and assisted reproduction--with or without gonadotropin-releasing hormone-agonist treatment--are reviewed. Finally we speculate about new developments in the field of endometriosis in the coming three years.

Molecular genetic evidence that endometriosis is a precursor of ovarian cancer

Histopathology and epidemiology studies have consistently demonstrated a strong link between endometriosis and endometriosis-associated ovarian cancers (EAOCs)--in particular, the endometrioid and clear cell subtypes. However, it is still unclear whether endometriosis is a precursor to EAOCs, or whether there is an indirect link because similar factors predispose to both diseases. In order to search for evidence of clonal progression, we analyzed 10 EAOCs (endometrioid=4; clear cell=6) with coexisting endometriosis for common molecular genetic alterations in both the carcinoma and corresponding endometriosis. We used 82 microsatellite markers spanning the genome to examine loss of heterozygosity (LOH) in the coexisting carcinoma and endometriosis samples. A total of 63 LOH events were detected in the carcinoma samples; twenty two of these were also detected in the corresponding endometriosis samples. In each case, the same allele was lost in the endometriosis and cancer samples. Interestingly, no marker showed LOH in the endometriosis alone. These data provide evidence that endometriosis is a precursor to EAOCs.

Association of endometriosis risk and genetic polymorphisms involving sex steroid biosynthesis and their receptors: a meta-analysis

Endometriosis is a sex steroids-dependent disease. It has been postulated that certain genetic polymorphisms involved in sex steroids biosynthesis and metabolisms may be associated with increased risk of developing endometriosis. Despite a deluge of reports of positive associations of endometriosis with numerous polymorphisms involving sex steroids production and metabolism, the results are often conflicting. We performed a meta-analysis of 12 association studies on 5 genes (CYP17, CYP19, AR, PR and ER). We found that many reported positive findings were not supported by the data due to faulty analysis. There have been no functional data that support a putative relationship of these genetic polymorphisms with endometriosis. A handful of positive findings so far have not been independently replicated, and should be viewed as preliminary. In addition, these findings should be counterbalanced by legitimate concerns of multiple comparisons, small prior probability of association with a particular polymorphism, proper selection of controls, and lack of replication (at least until now). In future association studies, it may be productive to put more thought to study design, execution, and data analysis.