Increased Expression of TGF-β1 Contributes to the Downregulation of Progesterone Receptor Expression in the Eutopic Endometrium of Infertile Women with Minimal/Mild Endometriosis

Endometriosis is a hormone-dependent disease associated with impaired immunoregulation. In our recent study, we have characterized the trascriptomic transformation of eutopic endometrium from patients with minimal/mild endometriosis and controls across the menstrual cycle. However, the regulatory mechanism of altered immune microenvironment in eutopic endometrial stromal cells (ESCs) remains unclear. Here, we want to explore the regulation of immune cell to progesterone resistance and endometrial receptivity in the eutopic ESCs by cytokine (TGF-β1), and to understand the effect of TGF-β1 on the decidualization of the eutopic ESCs. Primary culture of eutopic ESCs was performed to explore the effects of TGF-β1 on the expression of Smad and progesterone receptor (PR) and the in vitro decidualization. Additionally, co-immunoprecipitation (Co-IP) was used to explore the direct interaction between Smad and PR. We found an attenuate expression of PRB protein (p=0.026) after using TGF-β1 in eutopic ESCs, although the difference of PRA before and after treatment was not significant (p=0.678). Similarly, the results of qRT-PCR showed that the mRNA level of PR (p<0.001), PRB (p=0.003) and HOXA10 (p<0.001) decreased significantly after TGF-β1 treatment, but that increased (p<0.023, for all) after SB431542 treatment in the eutopic ESCs. Moreover, TGF-β1 has a negative effect on the in vitro decidualization of eutopic ESCs (p=0.003). And the group with treatment of both TGF-β1 and SB435142 in eutopic ESCs showed significant decidual-like changes with increased prolactin level (p=0.01). We did not observe any physical interaction between the PR and p-Smad3/Smad3 proteins by using Co-IP. By activating TGF-β/Smad signaling in eutopic ESCs, elevated TGF-β1 from CD45+ immune cells could attenuate expression of PR, and further decrease endometrial receptivity.

Identification of a Novel Cuproptosis-Related Gene Signature in Eutopic Endometrium of Women with Endometriosis

Endometriosis (EMs) is a life-long endocrine disorder and a common cause for female infertility and pelvic pain. The key characteristics of eutopic endometrium of EMs patients are high proliferative and migratory potentials. Cuproptosis is a recently identified copper- and-mitochondrial-dependent regulated cell death. Regretfully, its role in EMs remains unclear. In this study, Kyoto Encyclopedia of Genes and Genomes analyses of differentially expressed genes (DEGs) indicated strong activation of the PI3K-Akt-mTOR pathway and biological process analysis reported positive regulation of kinase activity. Next, we screened 11 cuproptosis-related DEGs and found all of them were downregulated in the EMs group, which indicated the suppression of cuproptosis in EMs. One key cuproptosis-related gene, PDHA1, was selected via support vector machine, random forest algorithm and lasso regularization to build a risk-scoring model, which was tested in both internal and external validations. In conclusion, the downregulation and kinase activity of PDHA1 may function with the PI3K-Akt-mTOR pathway in some way, which could suppress the cuproptosis level and account for the cancer-like pathology in EMs.

Characterising the immune cell phenotype of ectopic adenomyosis lesions compared with eutopic endometrium: A systematic review

Inflammation is implicated in the symptomatology and the pathogenesis of adenomyosis. Injury at the endo-myometrial interface causes inflammation and may facilitate the invasion of endometrium into the myometrium, forming adenomyosis lesions. Their presence causes local inflammation, resulting in heavy menstrual bleeding, chronic pelvic pain, and subfertility. Immunological differences have been described in the eutopic endometrium from women with adenomyosis compared to healthy endometrium, and differences are also expected in the adenomyotic lesions compared with the correctly sited eutopic endometrium. This systematic review retrieved relevant articles from three databases with additional manual citation chaining from inception to 24th October 2022. Twenty-two eligible studies were selected in accordance with PRISMA guidelines. Risk of bias assessments were performed, and the findings presented thematically. Ectopic endometrial stroma contained an increased density of macrophages compared with eutopic endometrium in adenomyosis. This was associated with an increase in pro-inflammatory cytokines (IL-6, IL-8, ILβ-1, C-X-C Motif Chemokine Receptor 1(CXCR1), Monocyte Chemoattractant Protein-1 (MCP-1)), and an imbalance of anti-inflammatory cytokines (IL-22, IL-37). Cells in ectopic lesions also contained a higher levels of toll-like receptors and immune-mediated enzymes. However, the studies were heterogeneous, with inconsistent reporting of immune cell density within epithelial or stromal compartments, and inclusion of samples from different menstrual cycle phases in the same group for analysis. A detailed understanding of the immune cell phenotypes present in eutopic and ectopic endometrium in adenomyosis and associated dysregulated inflammatory processes will provide further insight into the pathogenesis, to enable identification of fertility-sparing treatments as an alternative to hysterectomy.

Assessment of TET1 gene expression, DNA methylation and H3K27me3 level of its promoter region in eutopic endometrium of women with endometriosis and infertility

Endometriosis is the cause of infertility. The eutopic endometrium of women with endometriosis showed an aberrant expression pattern of multitude genes. The role of TET1 protein in the pathogenesis of endometriosis and related infertility is not sufficiently known. Further, knowledge on TET1 transcriptional control still remains incomplete. The aim of the study was assessment of TET1 gene expression, DNA methylation and H3K27me3 level of its promoter region in eutopic endometrium of women with endometriosis and infertility. The study included 44 infertile patients with endometriosis (IWE) and 77 infertile (IW) and fertile (FW) patients without endometriosis. The research material was eutopic endometrium. The TET1 mRNA level was analyzed by qPCR. Western blot was used to evaluate the level of TET1 protein. The level of DNA methylation and H3K27me3 level of TET1 gene's promoter region were assessed using HRM and ChIP qPCR, respectively. The level of TET1 expression (TET1 mRNA; TET1 protein level) was lower in IWE during the implantation window (p < 0.001; p = 0.0329). The level of TET1 DNA methylation was higher in the secretory endometrium in mild and advanced IWE (p < 0.004; p < 0.008). H3K27me3 level did not differ between the study groups. The diminished expression of TET1 gene during the secretory phase, may account for the aberrant process of embryonic implantation in infertile endometriosis patients. DNA hypermethylation of TET1 gene is a potential relevant regulator of its expression. H3K27me3 occupancy does not affect the expression of TET1 gene in our study group.

Expression of lncRNA NEAT1 in endometriosis and its biological functions in ectopic endometrial cells as mediated via miR-124-3p

BACKGROUND

Endometriosis (EM) is a gynecological disease that poses severe health risks to women, although its pathogenesis has yet to be fully elucidated. It has been shown that long non-coding RNAs (lncRNAs) are closely associated with EM initiation and have a role in the development of this disease. Previous studies exploring the expression of the lncRNA nuclear paraspeckle assembly transcript 1 (NEAT1) have shown that this lncRNA functions as a tumor promoter in endometrial cancer. However, its exact mechanism of action in EM remains unclear.

OBJECTIVE

This report was designed to illustrate the potential molecular mechanisms of lncRNA NEAT1 on EM.

METHODS

Endometrial tissues were extracted from EM model rats and patients with EM. Hematoxylin and eosin staining was applied to detect the morphological changes that occurred in rats after construction of the model. Endometrial stromal cells (ESCs) were extracted from either ectopic endometrium (EC) or eutopic endometrium (EU) tissues from patients with EM. LncRNA NEAT1 and miR-124-3p expression in EM tissues and cells were subsequently evaluated by reverse transcription-quantitative (RT-q)PCR analysis. MTT assay, flow cytometric analysis, western blot assay and Transwell assay were then employed to examine the effect of NEAT1 and miR-124-3p on EC-ESC proliferation, apoptosis, migration and invasion, respectively. The targeted relationship between lncRNA NEAT1 and miR-124-3p was subsequently confirmed by dual-luciferase and co-transfection assays.

RESULTS

MiR-124-3p was identified as a target of NEAT1, and could be negatively regulated by NEAT1 in EC-ESCs. The expression level of NEAT1 was evidently increased, whereas that of miR-124-3p was decreased, in the EM in vivo model, EM tissues and EC-ESCs from patients with EM. The loss-of-function assays further established that silencing of NEAT1 could inhibit EC-ESC proliferation, migration, and invasion, but it led to the promotion of apoptosis via targeting miR-124-3p.

CONCLUSIONS

NEAT1 is significantly upregulated in EM, promoting malignant behavior in EM through targeting miR-124-3p expression.

Oestrogen up-regulates DNMT1 and leads to the hypermethylation of RUNX3 in the malignant transformation of ovarian endometriosis

RESEARCH QUESTION

What is the mechanism of hypermethylation of runt-related transcription factor 3 (RUNX3) in the eutopic endometrium of endometriosis as biomarker in the malignant transformation of endometriosis?

DESIGN

Methylation-specific polymerase chain reaction was used to analyse the methylation status of RUNX3 in endometriosis-associated ovarian cancer (EAOC). Primary eutopic endometrial stromal cells (ESC) were isolated from the uteri of patients with ovarian endometriosis. After RUNX3 knockdown by RNA interference technology or ESC treated with oestradiol, the proliferation and invasion ability were evaluated in ESC by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and transwell assays.

RESULTS

The frequency of methylation of RUNX3 in neoplastic tissue in the EAOC group was significantly higher than that in the ectopic endometrium of the endometriosis group (P < 0.001), and the frequency of methylation of RUNX3 in the eutopic endometrium of the EAOC group was significantly higher than that in the endometriosis group (P < 0.001). However, there was no significant difference in the eutopic endometrium when compared between the endometriosis group and the control endometrium group (P = 0.233). Silencing RUNX3 promoted the proliferation and invasion of ESC (P < 0.001 and P < 0.001). Following intervention with oestrogen, it was observed that the oestradiol group showed higher levels of RUNX3 methylation (P < 0.001) and DNA methyltransferase 1 (DNMT1) mRNA and protein expression (P < 0.001 and P < 0.001), and lower RUNX3 mRNA and protein expression when compared with the ESC group (P < 0.001 and P < 0.001).

CONCLUSION

This study demonstrated that hypermethylation of the RUNX3 was related to the malignant transformation of endometriosis and that this process was related to corresponding changes in the eutopic endometrium. Furthermore, the 'oestrogen-DNMT1' signalling pathway may induce the hypermethylation of RUNX3 to promote the malignant transformation of endometriosis.

Histomorphological and Functional Features of the Eutopic Endometrium in Patients with Ovarian Endometriosis After Surgery-a Clinical Study

Endometriosis causes infertility and the alterations in endometrial receptivity. Pinopodia in eutopic endometrial epithelium may have significant implications in the endometriosis-associated infertility. The aim of this study is to ascertain whether the surgical interventions to remove endometrioid ovarian cysts (EOCs) can improve endometrial receptivity. The study included 172 patients of reproductive age with EOC, who underwent laparoscopic cystectomy. Aspiration endometrial biopsy was performed at 6 and 12 months after the surgery during the proliferation and secretion phases. Histopathology analysis included H&E staining and IHC. Morphometric studies were performed on endometrial biopsies collected during the proliferation phase of 28 patients, and the secretion phase of 12 patients. The expression of IHC markers for estrogen receptors (ER) and progesterone receptors (PR) and the percentage of cells containing pinopodia were determined. A significant increase in the ER and PR expression was observed in the epithelium during the "middle stage, proliferation phase" and in the stroma and glands during "middle stage, secretion phase". A delay in endometrial secretory transformation and statistically significant decrease in the number of pinopodia was observed on the apical surface of the cells. These structural and functional alterations were observed both at 6 and 12 months after cystectomy. The endometriosis-associated infertility after surgical intervention of EOC could be due to the extensive expression of ER and PR during the proliferation and secretion phases, as well as the delayed secretory transformation and impaired formation of pinopodia in the eutopic endometrium in the patients at 6 and 12 months after surgery.

Genome-wide expression analysis of endometrium before and after endometrioma surgery

OBJECTIVE

This study was planned to investigate possible alteration in the number of differentially expressed genes (DEGs) in eutopic endometrium before and after laparoscopic removal of the ovarian endometrioma.

STUDY DESIGN

Six infertile women with ovarian endometrioma who underwent laparoscopic endometrioma cystectomy and six fertile control subjects who underwent tubal sterilization were included the study. Endometrial samples were collected before and 3 months after surgery throughout the mid-luteal phase. Genome-wide expression profiling was performed with Illumina Human HT-12V4 microchip, a high density silica bead-based microarray which utilizing more than 47.000 probs. Illumina microsequence system was used to assess detection of p value for each probe in every sample. Probes revealing significant assessment (p < .05) were selected for comparative analysis.

RESULTS

We have detected 1478 DEGs in the comparison between endometrium of women with endometrioma and fertile controls. 118 out of 1478 genes (7.9 %) were significantly increased or decreased more than 1.5-fold in their expression. When the preoperative values of the control and patient groups are compared the number of DEGs was 243 (7.5 %). In 9 out of 243 genes, the fold change was found to be 1.5 and more (3.7 %). Comparison of the number of DEGs after endometrioma surgery and tubal ligation revealed that expression patterns of 1036 genes (33.7 %) were changed in endometrioma group. In 105 out of 1036 genes, the fold change was found to be 1.5 and above (10 %). A comparison using 2706 probes revealed changes in the expression patterns of 106 different genes (3.9 %) after endometrioma resection. In 4 out of 106 genes, the fold change was found to be 1.5 and above (3.7 %). The comparison using 6035 probes revealed changes in the expression patterns of 93 genes (1.5 %) after tubal ligation. None of the 93 genes had a fold change of 1.5 or higher. The number of DEGs in endometrioma groups after surgery was approximately 3-fold higher than control group.

CONCLUSIONS

Endometrium of women with endometrioma displayed abnormal expression of genes associated with implantation, immunological, endocrine and neuracrine functions. Positive alteration of the expression pattern of DEGs and signal transduction pathways following endometrioma surgery can improve the receptive capacity and implantation rates of eutopic endometrium.

Expression of nerve growth factor (NGF) in endometrium as a potential biomarker for endometriosis - Single tertiary care centre study

OBJECTIVE

to identify novel biomarkers for peritoneal endometriosis in eutopic endometrium thus giving an oportunity for non-invasive diagnosis.

DESIGN

A cross-sectional single-center study SETTING: tertiary care hospital PATIENTS: 49 patients subjected to laparoscopy because of suspected endometriosis, 33 patients out of the group qualified to the study had sufficient endometrial tissue taken and were in their follicular phase of menstrual cycle.

INTERVENTIONS

biopsy sampling of eutopic endometrial tissue during diagnostic or diagnostic and terapeutic laparoscopy, questionaires, MAIN OUTCOME MEASURE(S): qRT-PCR to evaluate the mRNA expression of selected candidate marker genes in endometrium: ARO1 (aromatase), CXCL8 (interleukin 8), NGF (nerve growth factor), VEGF-A (vascular endothelial growth factor A), PDGF-A (platelet-derived growth factor A).

RESULTS

mRNA expression of ARO1, CXCL8, VEGF-A and PDGF-A did not differ significantly between women with and without endometriosis. NGF mRNA expression was decreased in women with endometriosis.

CONCLUSIONS

Observed preliminary results suggest a possible role of NGF in early diagnosis of peritoneal endometriosis. The role of NGF changes in eutopic endometrium of patients with peritoneal endometriosis needs further evaluation.

Relationship between the methylation levels of Twist gene and pathogenesis of endometriosis

The purpose of this study was to investigate the difference of Twist gene promoter methylation among ovarian ectopic endometrium, eutopic endometrium and non-endometriosis (EMs) endometrium . 15 patients with reproductive age hospitalized at Department of obstetrics and gynecology affiliated to Medicine School of Zhejiang University from January 2013 to June 2016 were selected. Among them, 5 patients underwent laparoscopic surgery due to ovarian type EMs, and were selected after histologic confirmation. Ectopic endometrium and eutopic endometrium were obtained simultaneously. Normal endometrium was obtained from 5 cases of tubal infertility confirmed by hysteroscopy. Six pairs of primers for CpG island of Twist gene promoter were designed, and the difference of promoter methylation levels was detected by pyrosequencing method for methylation specific PCR (MSP) in three groups of endometrial tissues. The promoter of Twist gene is hypomethylated in some areas of ovarian ectopic endometrium and eutopic endometrium of ovarian endometriosis. It is speculated that the regional hypomethylation of Twist gene promoter in ovarian ectopic endometrium and eutopic endometrium may cause over-expression of Twist protein, which may directly lead to the pathogenesis of endometriosis.

Aberrant DNA methylation suppresses expression of estrogen receptor 1 (ESR1) in ovarian endometrioma

Background

In ovarian endometriomas (OE), the expression statuses of various steroid hormone receptors are altered compared with their expression statuses in eutopic endometrium (EE). For example, in OE, the expressions of estrogen receptor 1 (ESR1), which encodes ERα, and progesterone receptor (PGR) are downregulated, while the expression of ESR2, which encodes ERβ, is upregulated. The causes of these changes are unclear. DNA methylation of a specific region of a gene can result in tissue-specific gene expression. Such regions are called tissue-dependent and differentially methylated regions (T-DMRs). We previously reported that the tissue-specific expression of ESR1 is regulated by DNA methylation of a T-DMR in normal tissues. In the present study, we examined whether aberrant DNA methylation of the T-DMR is associated with the altered expressions of ESR1, ESR2 and PGR in OE.

Results

Gene expression levels of ESR1, ESR2 and PGR were measured by quantitative RT-PCR. The expression levels of ESR1 and PGR were significantly lower and the expression level of ESR2 was significantly higher in OE than in EE. DNA methylation statuses were examined with an Infinium HumanMethylation450K BeadChip and sodium bisulfite sequencing. DNA methylation at the T-DMRs of ESR1 were significantly higher in OE than in EE, but no significant differences were observed in the DNA methylation statuses of ESR2 and PGR.

Conclusions

Aberrant DNA methylation of the T-DMR was associated with the impaired expression of ESR1, but not the altered expressions of ESR2 and PGR, in OE.

Altered expression of 3´paralogus HOX A-D clusters in endometriosis disease: A case-control study

BACKGROUND

Endometriosis is a prevalent gynecological disease, with limited known etiology and more researches are required to identify its etiology. In this manner, there is no evidence for expression and function of 3´HOX genes in 4 clusters in the limb and pelvic organs such as the uterus and its disorders (Genes in the HOXA-D clusters are subdivided into 13 paralogous groups).

OBJECTIVE

This study designed to investigate the expression profile of 5 paralogous (1-5) in four clusters of HOX genes (A, B, C, and D) in ectopic and eutopic tissues of women with endometriosis compared to the normal endometrium.

MATERIALS AND METHODS

Samples were obtained from thirty patients (15 with and 15 without endometriosis) of reproductive age with normal menstrual cycles. The same patient provided both eutopic and ectopic tissues and control women were laparoscopically checked for the absence of endometriosis. The expression profile of these HOX genes was investigated by quantitative real-time polymerase chain reaction technique.

RESULTS

We observed significant up-regulation of some members of HOXC and D clusters (HOXD1, HOXD3, HOXC4 and HOXC5) in ectopic and eutopic tissues vs. control. Also, our data showed significant down-regulation of all of HOXA and HOXB paralogous except HOXA1 in ectopic tissues versus control.

CONCLUSION

Our data showed specific cluster dependent modulation of the HOX genes expression in endometriosis (over-expression of some HOX genes in cluster C and D and down-regulation of HOX genes in cluster A and B) in ectopic and eutopic tissues compare to control group. Therefore, it is possible that change of expression level of these genes in endometrium plays a role in the pathogenesis of endometriosis.

The Expression of MAS1, an Angiotensin (1-7) Receptor, in the Eutopic Proliferative Endometria of Endometriosis Patients

BACKGROUND/AIM

We demonstrated that AT1 and AT2 are expressed and both pathways balance the renin-angiotensin system in endometriosis. MAS1, a specific receptor of angiotensin (1-7), opposes AT1 pathway-associated tissue remodelling. It is not known whether MAS1 has an effect on the pathogenesis of endometriosis or not.

MATERIALS AND METHODS

Ovarian endometriotic tissues (endo-Ov) and eutopic endometrial tissues (endo-Em) were obtained from 29 patients with endometrial cysts. Normal endometrial tissues (cont-Em) were obtained from patients without endometriosis. Immunohistochemical staining was performed for MAS1, AT1 and AT2 in the endometriosis-associated tissues. The mRNA levels of these receptors were examined by quantitative reverse transcription PCR.

RESULTS

MAS1 was immune-positive at the apical side of the glandular epithelium in the endometriotic lesions. The MAS1 mRNA levels in endo-Ov were increased significantly, irrespective of the menstrual cycle phase. The MAS1 mRNA levels were significantly higher in the proliferative-tissues of the endometriosis patients than in those of the controls. The ratio of the MAS1 to the AT1 mRNA in the proliferative tissues was increased predominantly in the endometriosis patients compared with that in the controls.

CONCLUSION

High MAS1 expression in the endometrium might promote the initiation of endometriosis via migration of proliferative tissue.

Endometrium metabolomic profiling reveals potential biomarkers for diagnosis of endometriosis at minimal-mild stages

BACKGROUND

The sensitivity and specificity of non-invasive diagnostic methods for endometriosis, especially at early stages, are not optimal. The clinical diagnostic indicator cancer antigen 125 (CA125) performs poorly in the diagnosis of minimal endometriosis, with a sensitivity of 24%. Therefore, it is urgent to explore novel diagnostic biomarkers. We evaluated the metabolomic profile variation of the eutopic endometrium between minimal-mild endometriosis patients and healthy women by ultra-high-performance liquid chromatography coupled with electrospray ionization high-resolution mass spectrometry (UHPLC-ESI-HRMS).

METHODS

Our study comprised 29 patients with laparoscopically confirmed endometriosis at stages I-II and 37 infertile women who underwent diagnostic laparoscopy combined with hysteroscopy from January 2014 to January 2015. Eutopic endometrium samples were collected by pipelle endometrial biopsy. The metabolites were quantified by UHPLC-ESI-HRMS. The best combination of biomarkers was then selected by performing step-wise logistic regression analysis with backward elimination.

RESULTS

Twelve metabolites were identified as endometriosis-associated biomarkers. The eutopic endometrium metabolomic profile of the endometriosis patients was characterized by a significant increase in the concentration of hypoxanthine, L-arginine, L-tyrosine, leucine, lysine, inosine, omega-3 arachidonic acid, guanosine, xanthosine, lysophosphatidylethanolamine and asparagine. In contrast, the concentration of uric acid was decreased. Metabolites were filtered by step-wise logistic regression with backward elimination, and a model containing uric acid, hypoxanthine, and lysophosphatidylethanolamine was constructed. Receiver-operating characteristic (ROC) analysis confirmed the prognostic value of these parameters for the diagnosis of minimal/mild endometriosis with a sensitivity of 66.7% and a specificity of 90.0%.

CONCLUSIONS

Metabolomics analysis of the eutopic endometrium in endometriosis was effectively characterized by UHPLC-ESI-HRMS-based metabolomics. Our study supports the importance of purine and amino acid metabolites in the pathophysiology of endometriosis and provides potential biomarkers for semi-invasive diagnosis of early-stage endometriosis.

Direct Mass Spectrometry Differentiation of Ectopic and Eutopic Endometrium in Patients with Endometriosis

STUDY OBJECTIVE

To introduce a method for the rapid assessment of endometriotic tissues using direct mass spectrometry (MS)-based lipidomics.

DESIGN

A prospective observational cohort study (Canadian Task Force classification II2).

SETTING

Department of Operative Gynecology of the Research Centre for Obstetrics, Gynecology and Perinatology.

PATIENTS

Fifty patients with ovarian cysts and peritoneal endometriosis who underwent laparoscopic surgery between 2014 and 2016.

INTERVENTION

Differences in mass spectrometric profiles of ectopic endometria (endometriosis) and eutopic endometria were analyzed for each patient in combination with morphohistologic evaluation. The lipidomic approach was applied using a direct high-resolution MS method.

MEASUREMENTS AND MAIN RESULTS

Of 148 metabolites, 15 showed significant differences between endometriotic tissue and a healthy endometrium of the same patient, considered as a control in this study. The main lipids prevalent in endometriotic tissues were phosphoethanolamine (PE O-20:0), sphingomyelin (SM 34:1), diglycerides (DG 44:9), phosphatidylcholines (PC 32:1, PC O-36:3, PC 38:7, PC 38:6, PC 40:8, PC 40:7, PC 40:6, PC 40:9, and PC O-42:1), and triglycerides (TG 41:2, TG 49:4, and TG 52:3). Using partial least squares discriminant analysis models, MS showed that the lipidomic profile of endometriotic tissue (peritoneal endometriosis and ovarian endometriomas) was clearly separated from the eutopic endometrium, indicating tissue-type differentiation.

CONCLUSION

Our results suggest that direct MS may play an important role for endometriotic tissue identification. Such an approach has potential usefulness for real-time tissue determination and differentiation during surgical treatment. Lipids of 3 important classes, sphingolipids, phospholipids, and the fatty acids (di- and triglycerides), were identified. Validation is required to determine whether these lipids can be used to discriminate between patients with endometriosis and those with other gynecologic diseases.

Selection of reliable reference genes in eutopic and ectopic endometrium for quantitative expression studies

PURPOSE

Physiological changes during menstrual cycle cause the endometrium and endometriosis to develop specific kind of tissues, especially in regard to the gene expression profiles, which may include also housekeeping genes, commonly used as reference genes (RGs) in quantitative studies. Reverse transcription, followed by quantitative polymerase chain reaction (RT-qPCR) is the most precise and commonly used method in gene expression studies. In order to reduce effects of technical approaches and biological variability of gene's expression level, the studies often employ RGs in experimental data normalization. However, the expression of RGs is not always stable and depends on several variables. Thus, the selection of appropriate RG is one of the most significant steps to obtain reliable results in RT-qPCR-based methods.

MATERIAL AND METHODS

With the usage of RT-qPCR, we researched the expression of seven genes (ACTB, B2M, G6PD, GAPD, GUSB, HPRT and PPIA) as reliable reference genes in eutopic and ectopic endometrial tissue specimens obtained during standard surgery of women of reproductive age. Stability of expression level was analyzed by the most universal MS Excel plug-ins including: geNorm, NormFinder and BestKeeper. The descriptive statistics were evaluated using Statistica software.

RESULTS

The distribution of threshold (Ct) values was not equal. We identified genes with higher expression level (referring to Ct values) such as ACTB and B2M, medium e.g., GAPD and low expression level, e.g., G6PD and HPRT. We demonstrated that the stability of the analyzed reference genes was not homogenous, and different algorithms pointed to PPIA, GAPD and B2M as the most stable ones in eutopic and ectopic endometrium. On the contrary to these, GUSB and G6PD were the most unstable ones.

CONCLUSIONS

In RT-qPCR-based analyses of gene expression level in eutopic and ectopic endometrium, we strongly recommend that a minimum of two reference genes are to be used and we determined that the most suitable seem to be PPIA and GAPD.

Profiling of selected angiogenesis-related genes in proliferative eutopic endometrium of women with endometriosis

OBJECTIVE

To compare the expression level of the most relevant angiogenesis-related genes in the eutopic endometrium of women with and without endometriosis.

STUDY DESIGN

32 regularly menstruating patients (18 with endometriosis and 14 controls) underwent surgery in the proliferative phase of the cycle. Eutopic endometrium was collected by the use of aspirating biopsy prior to laparoscopy. Only patients with advanced (stage III and IV) histopathologically confirmed ovarian endometriosis were studied. Real-time PCR gene arrays were applied to examine the expression of 84 human angiogenesis-connected genes. Western-blot and enzyme-linked immunosorbent assays (ELISA) were used to confirm the expression of selected proteins.

RESULTS

We found significantly higher levels of AKT1 (p=0.003), TYMP (p=0.02), JAG1 (p=0.007), LAMA5 (p=0.005) and TIMP-1 (p=0.03) in eutopic endometrium of patients with endometriosis as compared with controls. By the use of Western blot we found clearly positive expression of AKT1 whereas ELISA assays confirmed expression of AKT1, TYMP, JAG1, LAMA5 and TIMP1.

CONCLUSION

Changes in the expression of selected genes might lead to or be a consequence of an early defect in the physiological activity of proliferative endometrium ultimately resulting in its overgrowth outside the uterine cavity.