Pathophysiology Of Endometriosis Research Articles

Expression of heme oxygenase in the eutopic and ectopic endometrium in patients with adenomyosis

Heme oxygenase (HO) is the rate-limiting enzyme that catalyzes the degradation of heme into iron, carbon monoxide, and biliverdin. This enzyme has important functions in cellular homeostasis, including the regulation of oxidative load, apoptosis, and inflammation. Two isoforms of HO, the inducible HO-1 and the constitutive HO-2, are expressed and are known to play a role in the normal human endometrium throughout the menstrual cycle, but there is little evidence for HO expression and behavior in adenomyosis, which is the occurrence of intramural ectopic endometrial tissue. The aim of this study was to investigate the presence and localization of the two HO isoforms in both eutopic and ectopic endometrium of women with adenomyosis during the menstrual cycle. The oxidative stress and apoptosis related to HO-1 expression were also assessed. The expression of HO-1 and HO-2 in both eutopic and ectopic endometrium was confirmed, and their levels in the ectopic endometrium were lower than those in the eutopic endometrium. The cyclic variability of HO expression was lost in the ectopic endometrium during the menstrual cycle, whereas this variability was apparent in the eutopic endometrium. Moreover, HO-1 expression corresponded to apoptotic events in the eutopic endometrium. Constitutive HO-2 expression corresponded to endometrial proliferation and degradation. These results reveal that both HO-1 and HO-2 contribute little in the pathophysiology of adenomyosis.

Characterization of periostin expression in human endometrium and endometriotic lesions

Objective(s): To investigate the expression of periostin in the eutopic and ectopic endometrium of women diagnosed as endometriosis and evaluate the role of periostin in the pathogenesis of endometriosis. Study design: In this study, the expression of periostin was evaluated in the endometrial specimens from 35 women diagnosed as endometriosis and from 30 healthy women. To assess the presence and localization of periostin throughout the menstrual cycle in both eutopic and ectopic endometrium of women with endometriosis, microscopic evaluation was conducted. It was also subsequently compared with normal endometrium. Results: In the eutopic and ectopic endometrium of women with endometriosis, immunoreactivities of periostin increased compared with those of normal endometrium. We also observed a cyclic variation in the eutopic stromal periostin immunoreactivity throughout their menstrual cycle because higher H score values were observed in the proliferative phase than those in the secretory phase. Conclusion(s): These findings indicated that periostin may be involved in the pathophysiology of endometriosis.

The role of NF-kappaB in endometriosis

The nuclear factor kappaB (NF-kappaB) is a ubiquitously expressed transcription factor playing vital roles in innate immunity and other processes involving cellular survival, proliferation, and differentiation. This review highlights the importance of NF-kappaB in the pathophysiology of endometriosis. Constitutive activation of NF-kappaB has been shown in endometriotic lesions. Complex interactions of NF-kappaB with steroid receptors and apoptotic molecules in endometriosis resulting in opposing roles of NF-kappaB are discussed. NF-kappaB regulates the expression of cytokines mediating autocrine self-amplifying cycles of cytokine release and NF-kappaB activation, leading to maintenance of inflammatory reactions in endometriosis. NF-kappaB can contribute to the increased ability of endometriotic cells to invade and adhere to the peritoneal surface by regulating the expression of matrix metaloproteinases. We are presenting the role of NF-kappaB to regulate vascularization and oxidative stress in endometriotic cells. Effects of drugs used for the treatment of endometriosis on NF-kappaB pathway are presented and we show how drugs that inhibit the NF-kappaB can mediate the progression of endometriosis. Novel therapeutic strategies involving the NF-kappaB and applied in endometriosis are also discussed.

Primate Model Research for Endometriosis

Endometriosis is defined as the existence of endometrial tissue outside the uterine cavity, and it includes a chronic, inflammatory reaction associated with female infertility and pelvic pain. Endometriosis occurs in 7 to 10% of women. Although it has been studied for more than 50 years, the pathogenesis and development of endometriosis are still poorly understood. There is no curative therapy for endometriosis, which often recurs after surgical or medical treatment. There is a consensus that the adverse current of menstrual blood plays a crucial role in the development of endometriosis. This places a major limitation on research using rodent models of endometriosis, although these are still widely employed, because rodents do not menstruate and endometriosis does not occur spontaneously in these animals. In fact, menstruation and spontaneous endometriosis only occur in women and some non-human primates, making models that employ non-human primates the best animal models for research into the pathogenesis, pathophysiology, spontaneous onset, and treatment of endometriosis. This review assesses the effectiveness and potential of the non-human primate models of endometriosis. It also describes the current findings and theories on the pathogenesis of endometriosis that have been obtained by research using non-human primates.

Co-cultured endometrial stromal cells and peritoneal mesothelial cells for an in vitro model of endometriosis

This paper demonstrates an in vitro model to simulate the microenvironment of endometriosis. We used microfluidic channels with cover slips to pattern and release endometrial stromal cells (ESCs) and human peritoneal mesothelial cells (HPMCs) in a way that mimicked the pathophysiology of peritoneal endometriosis. This approach enabled observation in real time interactions between ESCs and HPMCs both in their normal and pathological states. HPMCs from control individuals were able to resist the invasion of ESCs from both control and endometriotic individuals. By contrast, HPMCs from endometriotic individuals were unable to resist the invasion of ESCs from both normal and endometriotic individuals. We further analyzed the dynamics between HPMCs and ESCs from endometriotic individuals. HPMCs from endometriotic individuals relaxed their adhesion to each other at the beginning of invasion of ESCs, lose their adhesion to the substrate and apoptosed when surrounded by ESCs. These data implicate that the peritoneal physiology may play an important role in endometriosis.

Association of E-cadherin single nucleotide polymorphisms with the increased risk of endometriosis in Indian women

The objective of the present study was to investigate the association between gene E-cadherin single nucleotide polymorphisms (SNPs) and risk of developing endometriosis in Indian women and to evaluate the role of E-cadherin expression in the pathophysiology of endometriosis. A genetic association study was conducted in 715 endometriosis cases and 500 controls of Indian origin. We genotyped -160 C/A, +54 C/T and -347 G/GA SNPs of gene E-cadherin by PCR-sequencing and PCR-restriction fragment length polymorphism techniques. Haplotype frequencies for multiple loci and the standardized disequilibrium coefficient (D') for pair-wise linkage disequilibrium (LD) were assessed by Haploview Software. In addition, to better understand genetic contributions to the pathophysiology of endometriosis, the expression pattern of E-cadherin in the endometrium of women with and without endometriosis was analyzed by western blot and immunohistochemical analysis. The frequencies of -347GA/GA (P = 0.026) and -160A/A (P = 0.0019) genotypes and -347G/-160A/+54C (P = 0.007) and -347GA/-160A/+54C (P < 0.0001) haplotypes were significantly different between patients and controls. Strong LD was observed between -347G/GA and -160C/A loci (D' = 0.64) when compared with -347G/GA and +54C/T (D' = 0.585) or -160C/A and +54C/T (D' = 0.05) loci in cases. Furthermore, increased membranous E-cadherin expression was observed in cases than in controls. The expression seems to be genotype dependent. In conclusion, the E-cadherin -347GA/GA and -160A/A genotypes and -347GA/-160A/+54C and -347G/-160A/+54C haplotypes may jointly modify the risk of endometriosis in Indian women. In addition, the differential expression of E-cadherin may play an important role in pathogenesis of endometriosis.

Decreased concentrations of soluble interleukin-1 receptor accessory protein levels in the peritoneal fluid of women with endometriosis

Interleukin 1 (IL1) may play an important role in endometriosis-associated pelvic inflammation, and natural specific inhibitors, including soluble IL1 receptor accessory protein (sIL1RAcP) and soluble IL1 receptor type 2 (sIL1R2), are critical for counterbalancing the pleiotropic effects of IL1. The objective of this study was to evaluate the levels of sIL1RAcP, together with those of sIL1R2 and IL1β, in the peritoneal fluid of women with and without endometriosis. Peritoneal fluid samples were obtained at laparoscopy and assessed by ELISA. sIL1RAcP concentrations were reduced in endometriosis stages I-II and III-IV. sIL1R2 concentrations were decreased, and those of IL1β were significantly increased in endometriosis stages I-II. sIL1RAcP and sIL1R2 concentrations were significantly decreased in the secretory phase of the menstrual cycle, and IL1β concentrations were elevated in the proliferative and the secretory phases. sIL1RAcP and sIL1R2 concentrations were reduced in women with endometriosis who were infertile, fertile, suffering from pelvic pain or pain-free. However, IL1β concentrations were significantly reduced in women with endometriosis who were infertile or had pelvic pain. These changes may exacerbate the local peritoneal inflammatory reaction observed in women with endometriosis and contribute to endometriosis pathophysiology and the major symptoms of this disease.

The pharmacological NF-κB inhibitor BAY11-7085 suppresses expression of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 in TNF-α-stimulated human endometriotic stromal cells

Endometriosis is commonly associated with intraperitoneal inflammation. A growing body of evidence suggests that the interaction between the immune system and the endometrial systems may play a role in the initiation and progression of endometriosis. The aim of the study was to explore the effect of BAY11-7085 on the expression of these critical molecules involved in the pathophysiology of endometriosis in TNF-α-stimulated human ectopic endometrial stromal cells (HEESCs) isolated from patients with endometriosis.

Curcumin attenuates the expression of intercellular adhesion molecule-1, vascular cell adhesion molecule-1 and cytokines in TNF-α-stimulated human endometriotic stromal cells

Endometriosis is a chronic gynecological inflammatory disorder in which immune system deregulation may play a role in its initiation and progression. The aim of the study was to explore the effect of curcumin on the expression of these critical molecules involved in the pathophysiology of endometriosis in TNF-α-stimulated human ectopic endometrial stromal cells (HEESCs) isolated from women with endometriosis.

Simvastatin and resveratrol downregulate integrin αv/β3 and upregulate TIMP-2 gene expression in human endometrial stromal cells in the presence of inflammatory conditions

Recently we reported that simvastatin (SIM; competitive inhibitor of HMG-CoA reductase) and resveratrol (RES; 3,5,4'-trans-trihydroxystilbene, a natural polyphenol) reduce the number and the size of endometrial implants in a nude mouse model of human endometriosis. Increased expression of integrin αv/β3 and decreased expression of TIMP-2 play a role in the pathophysiology of endometriosis. The present study was undertaken to investigate the effect of SIM and RES on integrin αv/β3 and TIMP-2 gene expression in human endometrial stromal (HES) cells cultured in the presence of inflammatory challenge.

Retinoid acid suppresses lesion development, inhibits peritoneal cytokine secretion, and upregulates macrophage function in an immunocompetent mouse model of endometriosis

Previous work has suggested that retinoid acid (RA) could play a fundamental role in altering the pathophysiology of endometriosis. In this study, we examined the effects of RA on growth of endometriotic lesions, secretion of cytokines IL-6 and MCP-1, and expression of the macrophage differentiation marker CD38 in an immunocompetent mouse model of endometriosis.

Expression and localization of CXCL16 and CXCR6 in ovarian endometriotic tissues

Inflammatory mediators, including chemokines, may play crucial roles in the development of endometriosis. Therefore, we investigated the expression and localization of CXCL16 and its receptor, CXCR6, in ovarian endometriotic tissues. We also examined whether CXCL16 induces IL-8 production in endometriotic stromal cells. We performed immunohistochemical and Western blotting analyses of in vivo and in vitro samples. IL-8 production was assayed using an ELISA. Both CXCL16 and CXCR6 were expressed by endometriotic epithelial cells and stromal cells, but not normal ovarian stroma. A Western blotting analysis using primary cultured endometriotic stromal cells showed a constant expression of CXCL16 and CXCR6 in the proliferative phase, secretory phase and during gonadotropin-releasing hormone agonist therapy. CXCL16 induced IL-8 production in several endometriotic stromal cells in vitro. CXCL16 and CXCR6 might be involved in the pathophysiology of endometriosis through regulation of the inflammatory response.

DNA microarray analysis in endometriosis for development of more effective targeted therapies

Microarray technology has become a widely used tool for analyzing the expression of tens of thousands of genes simultaneously on high-density microarrays in a single experiment, together with the availability of the complete nucleotide sequence of the human genome. DNA microarray technologies are powerful tools in the laboratory setting for scientific research, hypothesis generation, and the production of leads for subsequent validation through more sophisticated technologies. Since 2002, and particularly in the past few years, the utility of various DNA microarray technologies in endometriosis has rapidly and tremendously evolved; DNA microarray studies provide extremely important information that enable a better understanding of pathophysiology and disease etiology. This is a review of the literature focused on new findings of endometriosis pathophysiology obtained using various microarray technologies: gene expression profiling, microarray-based comparative genomic hybridization (CGH) (array CGH) single nucleotide polymorphism (SNP) arrays, the combination of chromatin immunoprecipitation (ChIP) with hybridization of microarrays (ChIP-on-chip). The present review discusses the results of a decade of DNA microarray technology experience, with emphasis on the pathophysiology of endometriosis in the context of clinical studies.

Lien hypothétique entre l’endométriose et l’accumulation de xénobiotiques associés aux aliments génétiquement modifiés

Endometriosis is an oestrogen-dependant inflammatory disease affecting 10 % of reproductive-aged women. Often accompanied by chronic pelvic pain and infertility, endometriosis rigorously interferes with women's quality of life. Although the pathophysiology of endometriosis remains unclear, a growing body of evidence points to the implication of environmental toxicants. Over the last decade, an increase in the incidence of endometriosis has been reported and coincides with the introduction of genetically modified foods in our diet. Even though assessments of genetically modified food risk have not indicated any hazard on human health, xenobiotics-associated genetically modified food, such as pesticides residues and xenoproteins, could be harmful in the long-term. The “low-dose hypothesis”, accumulation and biotransformation of pesticides-associated genetically modified food and the multiplied toxicity of pesticides – formulation adjuvants support this hypothesis. This review summarizes toxic effects (in vitro and on animal models) of some xenobiotics-associated genetically modified food, such as glyphosate and Cry1Ab protein, and extrapolates on their potential role in the pathophysiology of endometriosis. Their roles as immune toxicants, pro-oxidants, endocrine disruptors and epigenetic modulators are discussed.

Polymorphism in Vitamin D-Binding Protein as a Genetic Risk Factor in the Pathogenesis of Endometriosis

Context: Previous studies have implicated a deficiency in the inflammatory response in women who develop endometriosis. The specific immunological deficits have not been completely elucidated. Objective: Our objective was to identify differences in protein expression in serum that might shed light on the pathophysiology of endometriosis. Design and Setting: This cross-sectional study of women undergoing laparoscopy between 2003 and 2005 took place at a university medical center. Patients: Patients included consenting women age 18-49 yr undergoing surgery for pain and/or infertility or elective tubal ligation. Women with acute or chronic medical conditions were excluded. Intervention: Blood was collected preoperatively. Main Outcome Measure: Proteomic analysis of serum was done using two-dimensional difference gel electrophoresis. Results: We found 25 protein spots with a significant difference in abundance between women with endometriosis and controls, including acute-phase proteins and complement components. The abundance of vitamin D-binding protein was higher in all endometriosis pools by a factor of approximately 3 compared with the control pool (P &amp;lt; 0.02). Analysis of specific allele products using nano-LC-ESI-MS indicated that it was the GC*2 allele product that was in greater concentration in serum pools, as well as in single validation samples, in women with endometriosis (P = 0.006). In contrast to the GC*1 allele product, which is readily converted to a potent macrophage factor (Gc protein-derived macrophage-activating factor), the GC*2 allele product undergoes practically no such conversion. Conclusions: We speculate that the inability to sufficiently activate macrophages’ phagocytotic function in those carrying the GC*2 polymorphism (more prevalent in endometriosis) may allow endometriotic tissues to implant in the peritoneal cavity. Future studies evaluating specific vitamin D-binding protein polymorphisms as a risk factor for endometriosis in larger populations of women are warranted.

Polymorphism in Vitamin D-Binding Protein as a Genetic Risk Factor in the Pathogenesis of Endometriosis

Context Previous studies have implicated a deficiency in the inflammatory response in women who develop endometriosis. The specific immunological deficits have not been completely elucidated. Objective Our objective was to identify differences in protein expression in serum that might shed light on the pathophysiology of endometriosis. Design and Setting This cross-sectional study of women undergoing laparoscopy between 2003 and 2005 took place at a university medical center. Patients Patients included consenting women age 18-49 yr undergoing surgery for pain and/or infertility or elective tubal ligation. Women with acute or chronic medical conditions were excluded. Intervention Blood was collected preoperatively. Main Outcome Measure Proteomic analysis of serum was done using two-dimensional difference gel electrophoresis. Results We found 25 protein spots with a significant difference in abundance between women with endometriosis and controls, including acute-phase proteins and complement components. The abundance of vitamin D-binding protein was higher in all endometriosis pools by a factor of approximately 3 compared with the control pool (P &amp;lt; 0.02). Analysis of specific allele products using nano-LC-ESI-MS indicated that it was the GC*2 allele product that was in greater concentration in serum pools, as well as in single validation samples, in women with endometriosis (P = 0.006). In contrast to the GC*1 allele product, which is readily converted to a potent macrophage factor (Gc protein-derived macrophage-activating factor), the GC*2 allele product undergoes practically no such conversion. Conclusions We speculate that the inability to sufficiently activate macrophages’ phagocytotic function in those carrying the GC*2 polymorphism (more prevalent in endometriosis) may allow endometriotic tissues to implant in the peritoneal cavity. Future studies evaluating specific vitamin D-binding protein polymorphisms as a risk factor for endometriosis in larger populations of women are warranted.

Dioxins in ascites and serum of women with endometriosis: a pilot study

Animal studies and laboratory experiments have demonstrated that exposure to dioxins may be involved in the pathophysiology of endometriosis. However, recent epidemiological investigations have shown conflicting results. Although peritoneal fluid is a specific microenvironment playing a pivotal role in the development of endometriosis, to our knowledge, there is no published study evaluating the concentrations of dioxins in serum and peritoneal fluid simultaneously. The present study explores the possible correlation between the local peritoneal fluid levels of dioxins and concurrent endometriosis. There were 17 infertile women enrolled in the present study. After the diagnostic laparoscopic examination, the women were divided into two groups: endometriosis (n = 10) and controls (n = 7). We measured 29 dioxins simultaneously in serum and peritoneal fluid samples: 7 polychlorinated dibenzo-p-dioxins (PCDDs), 10 polychlorinated dibenzofurans (PCDFs), and 12 polychlorinated biphenyls (dioxin-like PCBs). A dioxin toxic equivalency (TEQ) system was utilized to calculate the dioxin concentration in each sample. Serum concentrations of itemized components of 29 dioxins were similar in the endometriosis patients compared with the controls. Higher concentrations of PCDFs and dioxin-like PCBs were observed in peritoneal fluid than in serum, whereas the reverse was shown for PCDDs. Statistical analysis showed that higher levels of dioxin TEQ (PCDDs and PCDFs) in peritoneal fluid were significantly associated with an increased risk of endometriosis (OR: 2.5; 95% CI: 1.17-5.34; P = 0.035). This is the first report suggesting that higher concentrations of dioxins (PCDDs and PCDFs) in peritoneal fluid are linked to endometriosis. More detail and epidemiological research is warranted to further explore this link.

Macrophage Migration Inhibitory Factor Elicits an Angiogenic Phenotype in Human Ectopic Endometrial Cells and Triggers the Production of Major Angiogenic Factors via CD44, CD74, and MAPK Signaling Pathways

Abstract Context: An active angiogenesis is required for ectopic endometrial tissue growth. Our previous studies led to the identification of macrophage migration inhibitory factor (MIF), which is markedly elevated in active, vascularized, and early-stage endometriotic lesions, as a potent mitogenic factor for endothelial cells. Objective: Our objective was to study the mechanisms by which MIF may stimulate angiogenesis in ectopic endometrial implantation sites. Design: Primary cultures of ectopic endometrial cells were exposed to MIF, and the release of major angiogenic factors with targeted disruption of MIF signaling pathways was assessed. Patients: Patients were women found to have endometriosis during laparoscopy. Setting: The study was conducted at a hospital and reproduction research laboratory. Interventions: Biopsies were removed from endometriotic lesions. Main Outcome Measures: Vascular endothelial cell growth factor (VEGF), IL-8, and monocyte chemotactic protein-1 (MCP-1) mRNA and protein levels and expression and small interfering RNA silencing of MIF CD74/CD44 receptor complex and phosphorylation of ERK and p38 MAPKs were evaluated. Results: MIF markedly up-regulated VEGF, IL-8, and MCP-1 expression in endometriotic cells. Such an effect was abolished by (S,R)-3-(4-hydroxyphenyl)-4,5-dihydro-5-isoxazole acetic acid methyl ester (ISO-1), a specific inhibitor of MIF, and significantly down-regulated after specific small interfering RNA silencing of CD44 or CD74. MIF treatment strongly activated ERK and p38 MAPKs, and specific inhibitors of both pathways completely blocked basal and MIF-induced VEGF, IL-8, and MCP-1 synthesis. Conclusions: These results show for the first time that MIF exerts a potent indirect angiogenic effect by interacting with ectopic endometrial cells and inducing the secretion of major angiogenic factors via CD44, CD74, and MAPK signaling pathways and provide evidence for a possible new mechanism underlying endometriosis development and pathophysiology.

Insulinlike Growth Factor-1Ec (MGF) Expression in Eutopic and Ectopic Endometrium: Characterization of the MGF E-Peptide Actions In Vitro

The transcription of the insulinlike growth factor 1 (igf-1) gene generates three mRNA isoforms, namely IGF-1Ea, IGF-1Eb and IGF-1Ec (or MGF [mechano growth factor]). Herein, we analyzed the expression of IGF-1 isoforms in eutopic and ectopic endometrium (red lesions and endometriotic cysts) of women with endometriosis, and we characterized the actions of a synthetic MGF E-peptide on KLE cells. Our data documented that all three igf-1 gene transcripts are expressed in the stromal cells of the eutopic and ectopic endometrium; however, endometriotic cysts contained significantly lower IGF-1 isoform expression, both at the mRNA and protein level, as was shown using semiquantitative PCR and immunohistochemical methods. In addition, the glandular cells of the eutopic endometrium did not express any of the IGF-1 isoforms; however, the glandular cells of the ectopic endometrium (red lesions) did express the IGF-1Ec at mRNA and protein level. Furthermore, synthetic MGF E-peptide, which comprised the last 24 amino acids of the MGF, stimulated the growth of the KLE cells. Experimental silencing of the type 1 IGF receptor (IGF-1R) and insulin receptor expression of KLE cells (siRNA knock-out methods) did not alter the mitogenic action of the synthetic MGF E-peptide, revealing that MGF E-peptide stimulates the growth of KLE cells via an IGF-1R-independent and insulin receptor-independent mechanism. These data suggest that the IGF-1Ec transcript might generate, apart from mature IGF-1 peptide, another posttranslational bioactive product that may have an important role in endometriosis pathophysiology.

Retinoid acid suppresses growth of endometriotic implants in an immunocompetent mouse model of endometriosis

OBJECTIVE: Retinoid acid (RA) may play a fundamental role in altering the pathophysiology of endometriosis by suppressing interleukin-6 expression in primary endometrial stromal cells and by increasing certain functions of peritoneal macrophages. In this study, we examined the effects of RA on growth of endometriotic lesions in an immunocompetent mouse model of endometriosis.