Endométriose et génétique : les gènes sont-ils responsables de la maladie ?

Alteration of Nrf2 and Glutamate Cysteine Ligase expression contribute to lesions growth and fibrogenesis in ectopic endometriosis

The redox-sensitive nuclear factor erythroid-derived 2-like 2 (NRF2) controls endogenous antioxidant enzymes' transcription and protects against oxidative damage which is triggered by inflammation and known to favor progression of endometriosis. Glutamate Cysteine Ligase (GCL), a target gene of NRF2, is the first enzyme in the synthesis cascade of glutathione, an important endogenous antioxidant. Sixty-one patients, with thorough surgical examination of the abdominopelvic cavity, were recruited for the study: 31 with histologically-proven endometriosis and 30 disease-free women taken as controls. Expressions of NRF2 and GCL were investigated by quantitative RT-PCR and immunohistochemistry in eutopic and ectopic endometria from endometriosis-affected women and in endometrium of disease-free women. Ex vivo stromal and epithelial cells were extracted and purified from endometrial and endometriotic biopsies to explore expression of NRF2 and GCL in both stromal and epithelial compartments by western blot. Finally, in order to strengthen the role of NRF2 in endometriosis pathogenesis, we evaluated the drop of NRF2 expression in a mouse model of endometriosis using NRF2 knockout (NRF2^-/-) mice. The mRNA levels of NRF2 and GCL were significantly lower in ectopic endometria of endometriosis-affected women compared to eutopic endometria of disease-free women. The immunohistochemical analysis confirmed the decreased expression of both NRF2 and GCL in ectopic endometriotic tissues compared to eutopic endometria of endometriosis-affected and disease-free women. Immunoblotting revealed a significant decreased of NRF2 and GCL expression in epithelial and stroma cells from ectopic lesions of endometriosis-affected women compared to eutopic endometria from controls. Using a murine model of endometriosis, NRF2^-/- implants were more fibrotic compared to wild-type with an increased weight and volume. These findings indicate that expression of the transcription factor NRF2 and its effector GCL are both profoundly deregulated in endometriotic lesions towards increased growth and fibrogenetic processes.

A current view of the role of epigenetic changes in the aetiopathogenesis of endometriosis

The purpose of the study was to examine the role of epigenetic changes in the aetiopathogenesis of endometriosis. The analysis and review of the relevant current literature in English language related to the role of epigenetic changes in the aetiopathogenesis of endometriosis. Epigenetic changes are common denominators for hormonal, immunological and inflammatory aberrations which play a key role in the aetiopathogenesis of endometriosis. Many internal and external factors may cause the different running of the epigenetic mechanism. As yet fully unknown genetic factors may increase the sensitivity of the epigenetic mechanism to various internal and external factors. The breakdown of epigenetic regulation is the main factor initiating the pathogenetic mechanisms for endometriosis formation.

Protein oxidative stress markers in peritoneal fluids of women with deep infiltrating endometriosis are increased

STUDY QUESTION

Are protein oxidative stress markers [thiols, advanced oxidation protein products (AOPP), protein carbonyls and nitrates/nitrites] in perioperative peritoneal fluid higher in women with histologically proven endometriosis when compared with endometriosis-free controls?

SUMMARY ANSWER

Protein oxidative stress markers are significantly increased in peritoneal fluids from women with deep infiltrating endometriosis with intestinal involvement when compared with endometriosis-free controls.

WHAT IS KNOWN ALREADY

Endometriosis is a common gynaecologic condition characterized by an important inflammatory process. Various source of evidence support the role of oxidative stress in the development of endometriosis.

STUDY DESIGN, SIZE, DURATION

We conducted a prospective laboratory study in a tertiary-care university hospital between January 2011 and December 2012, and included 235 non-pregnant women, younger than 42 year old, undergoing surgery for a benign gynaecological condition.

PARTICIPANTS/MATERIALS, SETTING, METHODS

After complete surgical exploration of the abdomino-pelvic cavity, 150 women with histologically proven endometriosis and 85 endometriosis-free controls women were enrolled. Women with endometriosis were staged according to a surgical classification in three different phenotypes of endometriosis: superficial peritoneal endometriosis (SUP), ovarian endometrioma (OMA) and deeply infiltrating endometriosis (DIE). Perioperative peritoneal fluids samples were obtained from all study participants. Thiols, AOPP, protein carbonyls and nitrates/nitrites were assayed in all peritoneal samples.

MAIN RESULTS AND THE ROLE OF CHANCE

Concentrations of peritoneal AOPP were significantly higher in endometriosis patients than in the control group (median, 128.9 µmol/l; range, 0.3-1180.1 versus median, 77.8 µmol/l; range, 0.8-616.1; P < 0.001). In a similar manner concentrations of peritoneal nitrates/nitrites were higher in endometriosis patients than in the control group (median, 24.8 µmol/l; range, 1.6-681.6 versus median, 18.5 µmol/l; range, 1.6-184.5; P < 0.05). According to the surgical classification, peritoneal fluids protein AOPP and nitrates/nitrites were significantly increased only in DIE samples when compared with controls (P < 0.001 and P < 0.05; respectively), whereas the others forms of endometriosis (SUP and OMA) showed non-statistically significant increases. We found positive correlations between peritoneal fluids AOPP concentrations, nitrites/nitrates levels and the total number of intestinal DIE lesions (r = 0.464; P < 0.001 and r = 0.366; P = 0.007; respectively).

LIMITATIONS, REASONS FOR CAUTION

Inclusion of only surgical patients may constitute a possible selection bias. In fact, our control group involved women who underwent surgery for benign gynaecological conditions. This specificity of our control group may lead to biases stemming from the fact that some of these conditions, such as fibroids, ovarian cysts or tubal infertility, might be associated with altered peritoneal proteins oxidative stress markers.

WIDER IMPLICATIONS OF THE FINDINGS

We demonstrate the existence of a significantly increased protein oxidative stress status in peritoneal fluid from women with endometriosis especially in cases of DIE with intestinal involvement. This study opens the way to future more mechanistics studies to determine the exact role of protein oxidative stress in the pathogenesis of endometriosis. Even if an association does not establish proof of cause and effect, these intrinsic biochemical characteristics of endometriosis may lead to the evaluation of therapeutic approaches targeting oxidative imbalance.

STUDY FUNDING/COMPETING INTERESTS

No funding was used for this study. The authors have no conflict of interest.

Association of the progesterone receptor gene polymorphism (PROGINS) with endometriosis: a meta-analysis

BACKGROUND

Reported associations of progesterone receptor gene polymorphism (PROGINS) with endometriosis have been inconsistent.

AIM OF THE STUDY

To evaluate the association between the PROGINS polymorphism and the risk of endometriosis.

METHODOLOGY

A meta-analysis of 12 published case-control studies with a total sample size of 3,321 (1,323 cases/1,998 controls) was performed. We estimated the risk (odds ratio [OR] 95 % confidence intervals) of endometriosis association with the PROGINS polymorphism.

RESULTS

An association between the presence of the variant allele and risk of endometriosis was found, more in the homozygous and recessive models (OR 1.41-1.43, p = 0.15-0.17), and less in the dominant and co-dominant models (OR 1.22, p = 0.11-0.15). Reanalysis without the studies whose controls deviated from the Hardy-Weinberg Equilibrium did not materially alter the dominant and co-dominant effects (OR 1.19-1.22, p = 0.19-0.32), but exacerbated the homozygous and recessive effects (OR 1.59, p = 0.09). The subgroups based on geography showed increased risk associations, consistently significant in the European (OR 1.52-2.72, p = 0.0008-0.03) but not in the Brazilian studies, where ORs ranged from reduced (OR 0.70-0.74, p = 0.54-0.61) to increased (OR 1.11, p = 0.75) risks. Heterogeneity was confined in all comparisons to the dominant and co-dominant models (I (2) = 38-70 %), except in the European subgroup, which had zero heterogeneity (I (2) = 0 %) in all genetic models, as did all homozygous and recessive effects.

CONCLUSION

This meta-analysis provides a comprehensive profile of the role of the PROGINS polymorphism in endometriosis by exploring the magnitude of the summary effects with modifier analysis. This magnitude is expressed with modulation or exacerbation of the summary effects, as defined by the parameters of the analysis. Thus, the results showed trend towards an increased risk of the variant PROGINS allele and susceptibility for the endometriosis.

Genetic Polymorphisms Associated with Endometriosis in Pakistani Women

Background

Endometriosis is a common disease that causes pain and infertility. The heritable predisposition toward endometriosis motivates an interest to identify the genes and genomic variants involved in the pathogenesis of endometriosis. Both genetic and environmental factors contribute to this disease. Here we investigated in Pakistani women the association of endometriosis and single nucleotide polymorphisms (SNP) in genes previously identified in the development of this disease.

Methods

DNA samples from 52 genetically unrelated endometriosis subjects with endometriosis and 52 randomly selected controls were analyzed by direct sequencing to determine polymorphisms in four genes. These included estrogen receptor alpha (ESR1) (rs2234693 C/T, rs9340799 G/A SNP), estrogen receptor beta (ESR2) (rs4986938 G/A SNP), progesterone receptor (PGR) (rs1042838 G/T, rs10895068 G/A SNPs) and interleukin 10 (IL10) (rs1800871 C/T, rs1800872 C/A and rs1800896 G/A SNPs).

Results

The allele A at −592, T at −819 and G at −1080 of IL10 and all of the SNPs studied at ESR2 and PGR show strong, statistically significant associations with the disease. However, the genetic variation at ESR1 was distributed similarly among cases and control groups.

Conclusion

These findings suggest that the functional promoter polymorphism of the IL10 gene, identified by the “ATG” genotype, may contribute to the risk of endometriosis. Genetic variants of ESR2 and PGR gene may also be a risk factor as well as influence the fertility status of patients with endometriosis.

Increased serum oxidative stress markers in women with uterine leiomyoma

Background

Uterine leiomyomas (fibroids) are the most common gynaecological benign tumors in premenopausal women. Evidences support the role of oxidative stress in the development of uterine leiomyoma. We have analysed oxidative stress markers (thiols, advanced oxidized protein products (AOPP), protein carbonyls and nitrates/nitrites) in preoperative sera from women with histologically proven uterine leiomyoma.

Methodology/Principal Findings

We conducted a laboratory study in a tertiary-care university hospital. Fifty-nine women with histologically proven uterine leiomyoma and ninety-two leiomyoma-free control women have been enrolled in this study. Complete surgical exploration of the abdominopelvic cavity was performed in each patient. Preoperative serum samples were obtained from all study participants to assay serum thiols, AOPP, protein carbonyls and nitrates/nitrites.

Concentrations of serum protein carbonyl groups and AOPP were higher in leiomyoma patients than in the control group (p=0.005 and p<0.001, respectively). By contrast, serum thiol levels were lower in leiomyoma patients (p<0.001). We found positive correlations between serum AOPP concentrations and total fibroids weight (r=0.339; p=0.028), serum AOPP and serum protein carbonyls with duration of infertility (r=0.762; p=0.006 and r=0.683; p=0.021, respectively).

Conclusions/Significance

This study, for the first time, reveals a significant increase of protein oxidative stress status and reduced antioxidant capacity in sera from women with uterine leiomyoma.

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

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

Endometriosis gene expression heterogeneity and biosignature: a phylogenetic analysis

Endometriosis is a multifactorial disease with poorly understood etiology, and reflecting an evolutionary nature where genetic alterations accumulate throughout pathogenesis. Our objective was to characterize the heterogeneous pathological process using parsimony phylogenetics. Gene expression microarray data of ovarian endometriosis obtained from NCBI database were polarized and coded into derived (abnormal) and ancestral (normal) states. Such alterations are referred to as synapomorphies in a phylogenetic sense (or biomarkers). Subsequent gene linkage was modeled by Genomatix BiblioSphere Pathway software. A list of clonally shared derived (abnormal) expressions revealed the pattern of heterogeneity among specimens. In addition, it has identified disruptions within the major regulatory pathways including those involved in cell proliferation, steroidogenesis, angiogenesis, cytoskeletal organization and integrity, and tumorigenesis, as well as cell adhesion and migration. Furthermore, the analysis supported the potential central involvement of ESR2 in the initiation of endometriosis. The pathogenesis mapping showed that eutopic and ectopic lesions have different molecular biosignatures.