Increased secretion of hepatocyte growth factor by eutopic endometrial stromal cells in women with endometriosis

Changes in MCP-1, HGF, and IGF-1 expression in endometrial stromal cells, PBMCs, and PFMCs of endometriotic women following 1,25(OH)2D3 treatment

1,25(OH)2D3 has anti‐inflammatory and growth inhibitory effects. Our study explored the effect of 1,25(OH)2D3 treatment on the expression of monocyte chemotactic protein‐1 (MCP‐1), hepatocyte growth factor (HGF), and insulin‐like growth factor‐1 (IGF‐1) by peripheral blood mononuclear cells (PBMCs), peritoneal fluid mononuclear cells (PFMCs), endometrial stromal cells (ESCs), and its effect on the proliferation of PBMCs and PFMCs of patients with endometriosis compared with controls. PBMCs, PFMCs, and ESCs were obtained from 10 endometriosis patients and 10 non‐endometriotic individuals. After treating cells with 0.1 μM of 1,25(OH)2D3 for 6, 24, and 48 h, the gene and protein expression of mentioned factors were evaluated by real‐time PCR and ELISA methods, respectively. 1,25(OH)2D3 treatment significantly reduced the protein expression of MCP‐1, HGF, and IGF‐1 in PBMCs and PFMCs of endometriotic patients at 48 h (p < 0.05–<0.01). Also, this treatment significantly reduced MCP‐1, HGF, and IGF‐1 gene and/or protein expression in EESCs and EuESCs at 24 and 48 h (p < 0.05–<0.01). 1,25(OH)2D3 treatment also reduced the proliferation of PBMCs and PFMCs of endometriotic patients compared with controls (p < 0.01). 1,25(OH)2D3 can be considered as a potentially effective agent in the prevention and treatment of endometriosis along with other therapies.

Human Endometrial Organoids: Recent Research Progress and Potential Applications

Since traditional two-dimensional (2D) cell culture cannot meet the demand of simulating physiological conditions in vivo, three-dimensional (3D) culture systems have been developed. To date, most of these systems have been applied for the culture of gastrointestinal and neural tissue. As for the female reproductive system, the culture of endometrial and oviductal tissues in Matrigel has also been performed, but there are still some problems that remain unsolved. This review highlights recent progress regarding endometrial organoids, focusing on the signal for organoid derivation and maintenance, the coculture of the epithelium and stroma, the drug screening using organoids from cancer patients, and provides a potential guideline for genome editing in endometrial organoids.

Expression levels of MCP-1, HGF, and IGF-1 in endometriotic patients compared with non-endometriotic controls

BACKGROUND

To study the concentrations of monocyte chemoattractant protein-1 (MCP-1), hepatocyte growth factor (HGF), and insulin-like growth factor-1 (IGF-1) in peritoneal fluid (PF) and serum, and to evaluate their expressions by PF and peripheral blood mononuclear cells (PFMCs and PBMCs, respectively), and ectopic and eutopic endometrial stromal cells of patients with endometriosis (EESCs and EuESCs, respectively) compared with controls.

METHODS

The concentrations of mentioned cytokines in serum and PF, as well as their expression in PBMCs, PFMCs, EuESCs and EESCs from endometriosis patients and controls were assessed.

RESULTS

The levels of MCP-1, HGF, and IGF-1 in serum and PF in women with endometriosis were significantly higher than the controls (P < 0.05-P < 0.001). Gene expression of MCP-1 and IGF-1 in the PFMCs, PBMCs and EESCs also showed an increased level compared to controls (P < 0.05-P < 0.01). The protein expression of MCP-1 and IGF-1 by PFMCs was statistically higher in endometriotic women (P < 0.05 and P < 0.01, respectively). The gene and protein expression of HGF in PFMCs and its gene expression by EESCs were significantly higher in endometriotic women compared to controls (P < 0.05-P < 0.01).

CONCLUSIONS

The higher concentrations of mentioned cytokines in serum and PF and their higher expression by PFMCs and EESCs in endometriosis patients may contribute to the development of endometriosis.

Biological characteristics of endometriotic mesenchymal stem cells isolated from ectopic lesions of patients with endometriosis

BACKGROUND

Research into the pathogenesis of endometriosis (EMs) would substantially promote its effective treatment and early diagnosis. However, the aetiology of EMs is poorly understood and controversial despite the progress in EMs research in the last several decades. Currently, accumulating evidence has shed light on the importance of endometrial stem cells (EnSCs) residing in the basal layer of endometrium in the establishment and progression of endometriotic lesions. Therefore, we aimed to identify the differences between EnSCs isolated from the ectopic lesions of EMs patients (EnSC-EM-EC) and EnSCs isolated from eutopic endometrium of control group (EnSC-Control). We further performed preliminary exploration of the potential signalling pathways involved in the above abnormalities.

METHODS

EnSC-EM-EC (n = 12) and EnSC-Control (n = 13) were successfully isolated. Then, the proliferative capacity, migratory capacity and angiogenic potential of EnSCs were evaluated by conventional MTT assay, flow cytometry, wound healing assay, transwell assay, tube formation assay and chick embryo chorioallantoic membrane assay respectively. The expression of 11 angiogenesis-associated biological factors and 11 cytokines secreted by EnSCs and 17 adhesion molecules expressed on EnSCs were determined by protein array assays respectively. Differentially expressed genes (DEGs) between EnSC-EM-EC and EnSC-Control were analysed by RNA-sequence.

RESULTS

EnSC-EM-EC exhibited unique biological characteristics, including prolonged mitosis, enhanced migratory capacity and enhanced angiogenic potential. Greater amounts of angiogenic factors (especially VEGF and PDGF) were secreted by EnSC-EM-EC than by EnSC-Control; however, the distinct profiles of cytokines secreted by EnSC-EM-EC and adhesion molecules expressed by EnSC-EM-EC require further investigation. A total of 523 DEGs between EnSC-EM-EC and EnSC-Control were identified and analysed using the KEGG and Gene Ontology databases.

CONCLUSIONS

Our results not only improve the understanding of EMs but also contribute to the development of EnSC-EM-EC as a tool for EMs drug discovery. These cells could be of great help in exploiting promising therapeutic targets and new biomarkers for EMs treatment and prognosis.

Endometrial stromal cell inflammatory phenotype during severe ovarian endometriosis as a cause of endometriosis-associated infertility

RESEARCH QUESTION

Do endometrial stromal cells from primary infertile patients with severe ovarian endometriosis display differential secretory profiles of inflammation-associated cytokines during the implantation window that may cause infertility?

DESIGN

Forty-eight cytokines were measured in conditioned medium of isolated endometrial stromal cells obtained from primary infertile patients without endometriosis (control group, n = 12) or with stage IV ovarian endometriosis (ovarian endometriosis group, n = 14) using multiplex assays. Key cytokines showing differential secretory profiles were validated using Western immunoblotting. Cellular phenotypic validation was carried out in vitro by comparing proliferation and migration capacity between control (n = 6) and ovarian endometriosis (n = 7) groups.

RESULTS

CCL3, CCL4, CCL5, CXCL10, FGF2, IFNG, IL1RN, IL5, TNFA, and VEGF could be detected only in the conditioned media of stromal cells obtained from the ovarian endometriosis group. Among other cytokines detected in the conditioned media of both groups, CCL2 (P = 0.0018), CSF3 (P = 0.0017), IL1B (P = 0.0066), IL4 (P = 0.036), IL6 (P = 0.0039) and IL13 (P = 0.036) were found to be higher, whereas the concentration of IL18 was lower (P = 0.023) in the ovarian endometriosis group. Concentrations of CCL2, IL1B, IL4 and IL13 in conditioned medium reflected significant diagnostic performance for predicting ovarian endometriosis. Cellular phenotypic validation in vitro revealed an enhanced proliferative phenotype (P = 0.046) with no change in cell migratory capacity of endometrial stromal cells from the ovarian endometriosis group.

CONCLUSIONS

Endometrial stromal cells derived from severe ovarian endometriosis samples displayed a hyperinflammatory and hyperproliferative bias in the endometrial stroma during the 'window of implantation' putatively causing loss of fecundability.

Endometriotic lesions

Endometriosis is a complex gynaecological condition affecting women of reproductive age. It is characterised by the presence of lesions containing endometrial glands and stroma outside the uterus. The disease is typically associated with pelvic pain (including dysmenorrhoea and dyspareunia), infertility and bowel-related symptoms. Endometriotic lesions have a highly variable presentation and most commonly occur in the abdominal cavity. These lesions are broadly classified into peritoneal, ovarian and deep infiltrating endometriosis. There have been observations of increased density of nerve fibres and neurological molecules in the endometriotic lesions compared to the uninvolved peritoneum of women without endometriosis and the presence of unmyelinated nerve fibres were higher near the glands. The lesion sites are characterised by a range of immunological alterations, and specific immune cell populations have also been known to synthesise and secrete neurogenic factors. Endometriotic lesions are capable of producing prostaglandins which are direct generators of pain and are capable of inducing inflammation. Diagnosing the disease involves direct visualisation of the lesions through a laparoscopic or laparotomy, which is followed by histopathological examination of biopsied or excised lesions. The staging of endometriosis due to its complexity is highly variable as presentation and gaps in knowledge pose a great challenge in the classification of the disease. The medical management of endometriosis aims at providing adequate analgesia and suppression of the activity of the lesion. A better understanding of endometriotic lesion relationships between innervations and specific clinical characteristics may elucidate aspects of pain mechanisms and infertility in endometriosis and facilitate the development of novel therapeutic approaches.

Long-term, hormone-responsive organoid cultures of human endometrium in a chemically defined medium

In humans, the endometrium, the uterine mucosal lining, undergoes dynamic changes throughout the menstrual cycle and pregnancy. Despite the importance of the endometrium as the site of implantation and nutritional support for the conceptus, there are no long-term culture systems that recapitulate endometrial function in vitro. We adapted conditions used to establish human adult stem cell-derived organoid cultures to generate 3D cultures of normal and decidualised human endometrium. These organoids expand long-term, are genetically stable and differentiate following treatment with reproductive hormones. Single cells from both endometrium and decidua can generate a fully functional organoid. Transcript analysis confirmed great similarity between organoids and the primary tissue of origin. On exposure to pregnancy signals, endometrial organoids develop characteristics of early pregnancy. We also derived organoids from malignant endometrium, and so provide a foundation to study common diseases, such as endometriosis and endometrial cancer, as well as the physiology of early gestation.

The reduced PDCD5 protein is correlated with the degree of tumor differentiation in endometrioid endometrial carcinoma

Endometrial cancer is one of the most common malignancies in the female genital tract. Programmed cell death 5 (PDCD5) is a newly identified apoptosis related gene and plays an important role in the development of some human tumors. However, the expression and clinical significance of PDCD5 in endometrial cancer have not been fully elucidated. Here, we evaluated the expression of PDCD5 in endometrioid endometrial carcinoma and control endometrium by qRT-PCR, western blot and immunohistochemistry, and analyzed the associations of PDCD5 expression with clinicopathological parameters of patients. In addition, we detected the expression of PDCD5 in control endometrial glandular epithelial cells and endometrioid endometrial carcinoma-derived cell line KLE by immunocytochemistry. The results showed that PDCD5 protein mainly expressed in the cytoplasm of glandular epithelial cells and endometrial carcinoma cells, and there was a low level of PDCD5 expression in the nuclei of the above cells. Furthermore, PDCD5 protein level was significantly lower in endometrial carcinoma samples than that in control endometrium. The decreased PDCD5 expression was correlated with the tumor differentiation degree. It is clear that PDCD5 protein expression was lower in middle and low differentiated endometrial carcinoma compared with control endometrium and high differentiated endometrial carcinoma. However, there were no significant differences of PDCD5 expression between the proliferative phase and the secretory phase of control endometrium, as well as between high differentiated endometrial carcinoma and controls. The results were verified in control glandular epithelial cells and KLE cells by immunocytochemistry. Therefore, PDCD5 may play a key role in the pathogenesis of endometrial cancer and may be a novel target for diagnosis and treatment of endometrial cancer.

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.

Role of the CXCL12-CXCR4 axis in the development of deep rectal endometriosis

Immunological and angiogenetic factors enhance the implantation of endometrial cells in the peritoneal cavity. The aim of this work was to determine the role of the CXCL12-CXCR4 axis in the attraction and the peritoneal implantation of endometriotic stromal cells in deep infiltrating endometriosis (DIE). Biopsies of DIE nodules were obtained from 14 patients undergoing surgical treatment for DIE with low rectal involvement and from 12 patients without macroscopic endometriosis undergoing laparoscopy. CXCR4 expression was evaluated by Western blot analysis and flow cytometry in eutopic endometrial cells and DIE stromal cells in primary cultures derived from the biopsies. CXCL12-induced migration of DIE eutopic endometrial stromal cells was evaluated by transwell migration. CXCL12 was assayed in peritoneal fluids by ELISA. CXCR4 expression was higher in eutopic endometrial stromal cells than in control endometrial cells (p<0.05) and in DIE stromal cells (p<0.05). Eutopic endometrial stromal cells were more attracted by CXCL12 than control cells (p<0.01). CXCL12 was higher in DIE peritoneal fluids than in controls (p<0.05). CXCR4 was down-regulated in deep infiltrating endometriotic stromal cells. The CXCL12-CXCR4 axis plays a role in the attraction of eutopic endometrial cells into the peritoneal cavity, and the down-regulation of CXCR4 in resident endometriotic cells could cause their arrest in situ.

Metformin inhibits growth of eutopic stromal cells from adenomyotic endometrium via AMPK activation and subsequent inhibition of AKT phosphorylation: a possible role in the treatment of adenomyosis

Adenomyosis is a finding that is associated with dysmenorrhea and heavy menstrual bleeding, associated with PI3K/AKT signaling overactivity. To investigate the effect of metformin on the growth of eutopic endometrial stromal cells (ESCs) from patients with adenomyosis and to explore the involvement of AMP-activated protein kinase (AMPK) and PI3K/AKT pathways. Primary cultures of human ESCs were derived from normal endometrium (normal endometrial stromal cells (N-ESCs)) and adenomyotic eutopic endometrium (adenomyotic endometrial stroma cells (A-ESCs)). Expression of AMPK was determined using immunocytochemistry and western blot analysis. 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assays were used to determine the effects of metformin and compound C on ESCs and also to detect growth and proliferation of ESCs. AMPK and PI3K/AKT signaling was determined by western blotting. A-ECSs exhibited greater AMPK expression than N-ESCs. Metformin inhibited proliferation of ESCs in a concentration-dependent manner. The IC50 was 2.45 mmol/l for A-ESCs and 7.87 mmol/l for N-ESCs. Metformin increased AMPK activation levels (p-AMPK/AMPK) by 2.0±0.3-fold in A-ESCs, 2.3-fold in A-ESCs from the secretory phase, and 1.6-fold in the proliferation phase. The average reduction ratio of 17β-estradiol on A-ESCs was 2.1±0.8-fold in proliferative phase and 2.5±0.5-fold in secretory phase relative to the equivalent groups not treated with 17β-estradiol. The inhibitory effects of metformin on AKT activation (p-AKT/AKT) were more pronounced in A-ESCs from the secretory phase (3.2-fold inhibition vs control) than in those from the proliferation phase (2.3-fold inhibition vs control). Compound C, a selective AMPK inhibitor, abolished the effects of metformin on cell growth and PI3K/AKT signaling. Metformin inhibits cell growth via AMPK activation and subsequent inhibition of PI3K/AKT signaling in A-ESCs, particularly during the secretory phase, suggesting a greater effect of metformin on A-ESCs from secretory phase.

Additive effects of inflammation and stress reaction on Toll-like receptor 4-mediated growth of endometriotic stromal cells

STUDY QUESTION

Is there any combined effect between inflammation and stress reaction on Toll-like receptor 4 (TLR4)-mediated growth of endometriotic cells?

SUMMARY ANSWER

A combined effect of local inflammation and stress reaction in the pelvic environment may be involved in TLR4-mediated growth of endometriotic stromal cells.

WHAT IS KNOWN ALREADY

In endometriosis, higher endotoxin levels in the menstrual fluid (MF) and peritoneal fluid (PF) and higher tissue concentrations of human heat shock protein 70 (HSP70) in the eutopic and ectopic endometria promote TLR4-mediated growth of endometriotic cells.

STUDY DESIGN, SIZE AND DURATION

This is a case-controlled research study with prospective collection and retrospective evaluation of sera, MF, PF and endometrial tissues from 43 women with and 20 women without endometriosis.

PARTICIPANTS/MATERIALS, SETTING, METHODS

PF was collected from 43 women with endometriosis and 20 control women during laparoscopy. Sera and endometrial biopsy specimens were collected from a proportion of these women. MF was collected from a separate population of 20 women with endometriosis and 15 control women. HSP70 concentrations in sera, MF, PF and in culture media were measured by ELISA. Gene expression of HSP70 by endometrial cells in response to lipopolysaccharide (LPS) was examined by qRT-PCR. The individual and combined effects of LPS and HSP70 on the secretion of interleukin-6 (IL-6) and tumor necrosis factor α (TNFα) by PF-derived macrophages (M[Symbol: see text]) were examined by ELISA, while their effects on endometrial cell proliferation were examined by bromodeoxyuridine and [(3)H]-thymidine incorporation assay.

MAIN RESULTS AND THE ROLE OF CHANCE

Concentrations of HSP70 were maximal in MF, intermediate in PF and the lowest in sera. In MF and PF, HSP70 levels were higher in women with endometriosis than in controls. LPS stimulated gene expression and secretion of HSP70 by eutopic endometrial stromal cells (ESCs) and this effect was abrogated after pretreatment of cells with an anti-TLR4 antibody. This effect was significantly higher for ESCs derived from women with endometriosis than for ESCs from control women. Exogenous treatment with either HSP70 or LPS significantly stimulated the production of IL-6 and TNFα by M[Symbol: see text] and promoted the proliferation of ESCs, and a significant additive effect between LPS and HSP70 was observed. While individual treatment with either polymyxin B, an LPS antagonist, or anti-HSP70 antibody was unable to suppress the combined effects of LPS and HSP70 on cytokine secretion or ESC proliferation, pretreatment of cells with the anti-TLR4 antibody was able to significantly suppress their combined effects.

LIMITATIONS, REASONS FOR CAUTIONS

Further studies are needed to examine the mutual role between other secondary inflammatory mediators and endogenous stress proteins in promoting pelvic inflammation and growth of endometriotic stromal cells.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings suggest that endotoxin and HSP70 are mutually involved in a stress reaction and in inflammation. A combined effect between local inflammation and a stress reaction in pelvic environment may be involved in TLR4-mediated growth of endometriotic cells. Since endometriosis is a multi-factorial disease, it is difficult to explain uniformly its growth regulation by a single factor. Our findings may provide some new insights in understanding the physiopathology or pathogenesis of endometriosis and may hold new therapeutic potential.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by Grants-in-Aid for Scientific Research (grant no. 16591671 and 18591837) from the Ministry of Education, Sports, Culture, Science and Technology of Japan (to K.N.K.). There is no conflict of interest related to this study.

TRIAL REGISTRATION NUMBER

Not applicable.

Pathogenesis and pathophysiology of endometriosis

Originally described over three hundred years ago, endometriosis is classically defined by the presence of endometrial glands and stroma in extrauterine locations. Endometriosis is an inflammatory, estrogen-dependent condition associated with pelvic pain and infertility. This work reviews the disease process from theories regarding origin to the molecular basis for disease sequelae. A thorough understanding of the histopathogenesis and pathophysiology of endometriosis is essential to the development of novel diagnostic and treatment approaches for this debilitating condition.

Growth mechanisms of endometriotic cells in implanted places: a review

Endometriosis is a common gynecological disease defined by extrauterine growth of endometrial glands and stroma. A variety of theories have been proposed to account for the pathogenesis of this disease, including retrograde transplantation theory, metaplasia of coelomic epithelium, hematogenic and lymphogenic spread, and remnants of the Mŭllerian duct. However, the etiopathology of endometriosis is still obscure. In this article, we aim to summarize recent researches concerning the growth mechanisms of endometriotic cells in implanted sites systematically, including the adhesion, invasion, angiogenesis, proliferation, apoptosis of endometriotic cells, variations of the immune molecules and endometriotic cells themselves, which may provide clues for future researches in the pathogenesis of endometriosis.

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.

Effect of estradiol on proliferation and differentiation of side population stem/progenitor cells from murine endometrium

BACKGROUND

In our previous study, endometrium side population cells (SP cells) were isolated from postpartum murine uterus, and characterized by a heterogeneous population of stem/progenitor cells. In this study, we investigated the effect of estrogen on the proliferation and differentiation of SP cells.

METHODS

SP and non-SP cells of postpartum murine endometrium were isolated by DNA dye Hoechst 33342. The expression of estrogen receptor 1 (ESR1) was measured by reverse transcription polymerase chain reaction (RT-PCR), Real-time PCR, Western blot, immunofluorescence and immunohistochemistry. The proliferation and differentiation of SP cells treated with different concentrations [10(-8) M-10(-6) M] of estradiol (E2) and E2+ ICI182780 (Faslodex, inhibitor of ESR1) were measured by 3-(4, 5-dimethylthiazoly1-2)-2,5-diphenyltetrazolium bromide(MTT) and clonogenic assays.

RESULTS

(1) SP cells expressed ESR1 at a higher level than non-SP cells. (2) The level of E2 in the serum and the expression of ESR1 in the uterus of postpartum murine changed in the same manner with the ratio of SP cells to total uterus cells at a different postpartum time point. ESR1, as ABCG2 is also predominantly located in the stroma and the glandular epithelium of the uterus. (3) 10(-6) M E2 notably promoted the proliferation of SP cells after treatment for 24 h. This effect could be inhibited by ICI182780. E2 at the concentration of 10(-7) M or 10(-8) M was sent to impair the large cloning efficiency (CE) of SP cells.

CONCLUSIONS

The effect of estrogen on the proliferation and differentiation of endometrium SP cells via ESR1 was observed and it was in a concentration dependent fashion. Clearly, more work is needed to understand the in vivo effect of E2 at the physiological concentration on the differentiation of SP cells.

Endometriotic epithelial cells induce MMPs expression in endometrial stromal cells via an NFkappaB-dependent pathway

OBJECTIVE

To explore the stroma-epithelium interactions in endometriosis and to identify the possible signalling pathways involved in this cross-talk.

DESIGN

Laboratory study via primary cultured endometrial stromal and epithelial cells.

SETTING

University Hospital.

PATIENTS

Fifteen patients with endometriosis confirmed by histopathology were recruited in the study, and 12 women free of endometriosis were used as control group.

INTERVENTION(S)

Specific NFkappaB inhibitor 1-Pyrrolidinecarbodithioic acid ammonium salt (PDTC) was used in cell cultures.

MAIN OUTCOME MEASURE(S)

The expression and secretion of MMP-2, MMP-9, TIMP-1, TIMP-2 and the DNA-binding activity of NFkappaB in normal endometrial stromal cells or in co-cultures with normal or endometriotic epithelial cells from patients with endometriosis.

RESULT(S)

Endometrial epithelial cells induced MMP-9 and MMP-2 expression in normal stromal cells in vitro. In co-cultures with endometriotic epithelial cells, normal endometrial stromal cells expressed and secreted higher MMP-2 (p < 0.05) and MMP-9 (p < 0.05). Specific inhibition of NFkappaB pathway in stromal cells abolished this induction effect by epithelial cells.

CONCLUSION(S)

Endometriotic epithelial cells induce MMPs expression and secretion in normal endometrial stromal cells via an NFkappaB-dependent pathway in vitro. This cross-talk between epithelial cells and stromal cells may facilitate the implantation and extension of the ectopic foci and favour the development of the disease.

Endometriotic stromal cells lose the ability to regulate cell-survival signaling in endometrial epithelial cells in vitro

In normal endometrium, stromal factors regulate the growth of epithelial cells. However, epithelial cells in endometriotic lesions display increased proliferation and decreased apoptosis. This work tested the hypothesis that in endometriosis stromal cells lose the ability to regulate survival signaling and cell growth in epithelial cells. Primary normal, endometriotic eutopic and ectopic epithelial cells were cultured in the presence of medium conditioned by normal, eutopic and ectopic endometriotic endometrial stromal cells. Endometriotic epithelial cells showed higher Survivin expression than normal epithelial cells. Conditioned medium (CM) from normal or eutopic endometriotic stromal cells significantly inhibited the Survivin expression and AKt phosphorylation in normal or eutopic endometriotic epithelial cells. However, CM from ectopic endometriotic stromal cells did not have an inhibitory effect on normal or ectopic endometriotic epithelial cells. Inhibition of AKt phosphorylation and Survivin expression in normal or eutopic endometriotic epithelial cells in the presence of stromal factors from normal or eutopic endometriotic stromal cells was enhanced by progesterone, whereas progesterone had little effect in the presence of stromal factors from ectopic endometriotic stromal cells. The inability of ectopic endometriotic stromal cells to regulated PI3K/AKt/Survivin signaling and mediate the progesterone response in endometriotic epithelial cells may facilitate epithelial cell proliferation in endometriosis and promote the survival of endometriotic lesions.

Reactive oxygen species controls endometriosis progression

Endometriosis is associated with chronic inflammation, and reactive oxygen species (ROS) are proinflammatory mediators that modulate cell proliferation. We have investigated whether the dysregulation of ROS production in endometriotic cells correlates with a pro-proliferative phenotype and can explain the spreading of this disease. Stromal and epithelial cells were purified from ovarian endometrioma and eutopic endometrium from 14 patients with endometriosis to produce four primary cell lines from each patient. ROS production, detoxification pathways, cell proliferation, and mitogen-activated protein kinase pathway activation were studied and compared with epithelial and stromal cell lines from 14 patients without endometriosis. Modulation of the proliferation of endometriosis by N-acetyl-cysteine, danazol, and mifepristone was tested in vitro and in 28 nude mice implanted with endometriotic tissue of human origin. Endometriotic cells displayed higher endogenous oxidative stress with an increase in ROS production, alterations in ROS detoxification pathways, and a drop in catalase levels, as observed for tumor cells. This increase in endogenous ROS correlated with increased cellular proliferation and activation of ERK1/2. These phenomena were abrogated by the antioxidant molecule N-acetyl-cysteine both in vitro and in a mouse model of endometriosis. Human endometriotic cells display activated pERK, enhanced ROS production, and proliferative capability. Our murine model shows that antioxidant molecules could be used as safe and efficient treatments for endometriosis.

Immunopathogenesis of pelvic endometriosis: role of hepatocyte growth factor, macrophages and ovarian steroids

Endometriosis, a chronic disease characterized by endometrial tissue located outside the uterine cavity is associated with chronic pelvic pain and infertility. However, an in-depth understanding of the pathophysiology of endometriosis is still elusive. It is generally believed that besides ovarian steroid hormones, the growth of endometriosis can be regulated by innate immune system in pelvic microenvironment by their interaction with endometrial cells and immune cells. We conducted a series of studies in perspectives of pelvic inflammation that is triggered primarily by bacterial endotoxin (lipopolysaccharide) and is mediated by toll-like receptor 4 and showed their involvement in the development of pelvic endometriosis. As a cellular component of innate immune system, macrophages were found to play a central role in inducing pelvic inflammatory reaction. We further report here that peritoneal macrophages retain receptors encoding for estrogen and progesterone and ovarian steroids also participate in producing an inflammatory response in pelvic cavity and are involved in the growth of endometriosis either alone or in combination with hepatocyte growth factor (HGF). As a pleiotropic growth factor, HGF retains multifunctional role ometriosis. We describe here the individual and step-wise role of HGF, macrophages and ovarian steroid hormones and their orchestrated involvement in the immunopathogenesis of pelvic endometriosis.

Hormone and growth factor signaling in endometrial renewal: role of stem/progenitor cells

The human endometrium is a dynamic remodeling tissue undergoing more than 400 cycles of regeneration, differentiation and shedding during a woman's reproductive years. The co-ordinated and sequential actions of estrogen and progesterone direct these major remodeling events preparing a receptive endometrium for blastocyst implantation on a monthly basis. Adult stem/progenitor cells are likely responsible for endometrial regeneration. Functional approaches have been used to identify candidate endometrial stem/progenitor cells, as there are no specific stem cell markers. Rare populations of human endometrial epithelial and stromal colony-forming cells/units (CFU) and side population (SP) cells have been identified. Several growth factors are required for CFU activity: epidermal growth factor (EGF), transforming growth factor alpha (TGFalpha) and platelet-derived growth factor BB (PDGF-BB) for both epithelial and stromal CFU, and basic fibroblast growth factor (bFGF) for stromal, but not epithelial CFU. A sub-population of human endometrial stromal cells with mesenchymal stem cell properties of CFU activity and multilineage (fat, muscle, cartilage and bone) differentiation have been isolated by their co-expression of CD146 and PDGF-receptor beta. Candidate epithelial and stromal stem/progenitor cells have been identified in mouse endometrium as rare label retaining cells (LRCs) in the luminal epithelium and as perivascular cells at the endometrial-myometrial junction, respectively. While epithelial and most stromal LRC do not express estrogen receptor alpha (Esr1), they rapidly proliferate on estrogen stimulation, most likely mediated by neighbouring Esr1-expressing niche cells. It is likely that these newly identified endometrial stem/progenitor cells may play key roles in the development of gynecological diseases associated with abnormal endometrial proliferation such as endometriosis and endometrial cancer.

Altered expression of HOXA10 in endometriosis: potential role in decidualization

Endometriosis is a poorly understood gynaecologic disorder that is associated with infertility. In this study, we examined the expression of HOXA10 in the eutopic endometrium of baboons with induced endometriosis. A decrease in HOXA10 mRNA was observed after 3, 6, 12 and 16 months of disease, which reached statistical significance at 12 and 16 months. HOXA10 protein levels were decreased in both the epithelial and stromal cells of the endometrium. Furthermore, expression of beta3 integrin (ITGB3), which is upregulated by HOXA10, was decreased, whereas EMX2, a gene that is inhibited by HOXA10, was increased. Next, methylation patterns of the HOXA10 gene were analysed in the diseased and control animals. The F1 region on the promoter was found to be the most significantly methylated in the endometriosis animals and this may account for the decrease in HOXA10 expression. Finally, we demonstrate that stromal cells from the eutopic endometrium of baboons with endometriosis expressed significantly higher levels of insulin-like growth factor binding protein-1 (IGFBP1) mRNA than disease-free animals in response to estradiol, medroxyprogesterone acetate and dibutyryl cAMP (H + dbcAMP). The functional role of HOXA10 in IGFBP1 expression was further explored using human endometrial stromal cells (HSC). Overexpression of HOXA10 in HSC resulted in a decrease of IGFBP1 mRNA, whereas silencing HOXA10 caused an increase of IGFBP1 mRNA, even in the presence of H + dbcAMP. These data demonstrate that HOXA10 negatively influences IGFBP1 expression in decidualizing cells. Thus, the decrease in HOXA10 levels may in part be involved with the altered uterine environment associated with endometriosis.

Interleukin-6- and tumour necrosis factor alpha-mediated expression of hepatocyte growth factor by stromal cells and its involvement in the growth of endometriosis

BACKGROUND

We investigated the expression of the hepatocyte growth factor (HGF) gene and protein by the stromal cells derived from women with or without endometriosis and its regulation by interleukin-6 (IL-6) and tumour necrosis factor alpha (TNFalpha).

METHODS

Stromal cells immunoreactive to vimentin were isolated from the eutopic and ectopic endometrium of 18 infertile women with endometriosis and 12 women without endometriosis. The production of HGF in the culture media of basal and IL-6- or TNFalpha-stimulated stromal cells was examined with an enzyme-linked immunosorbent assay. The mRNA expression of HGF and its receptor c-Met in the stroma was investigated by RT-PCR. The localization of HGF and c-Met in isolated stromal cells and in intact tissue was examined by immunohistochemistry. The effect of HGF on the growth of stromal cells alone or in combination with IL-6 or TNFalpha was examined in a bromodeoxyuridine (BrdU) incorporation study.

RESULTS

The production of HGF in the culture medium of stromal cells was significantly increased after single or combined treatment with either IL-6 or TNFalpha when compared with non-treated cells. The production of HGF by stromal cells derived from the eutopic endometrium of women with endometriosis was significantly higher than that of cells from women without endometriosis. This effect was paralleled by increased expression of HGF and c-Met mRNA, as demonstrated by RT-PCR. The BrdU incorporation study indicated that the addition of HGF enhanced the growth of endometrial and endometriotic stroma alone or in combination with IL-6 or TNFalpha.

CONCLUSION

IL-6 and TNFalpha are involved in the production of HGF by endometrial stromal cells and may be involved in the growth of endometriosis by an autocrine mechanism.

Endometriosis

Endometriosis is an oestrogen-dependent disorder that can result in substantial morbidity, including pelvic pain, multiple operations, and infertility. New findings on the genetics, the possible roles of the environment and the immune system, and intrinsic abnormalities in the endometrium of affected women and secreted products of endometriotic lesions have given insight into the pathogenesis of this disorder and serve as the background for new treatments for disease-associated pain and infertility. Affected women are at higher risk than the general female population of developing ovarian cancer, and they also may be at increased risk of breast and other cancers as well as autoimmune and atopic disorders. Clinicians should assess and follow up affected women for these and other associated disorders. There will probably be a new repertoire of approaches for treatment and perhaps cure of this enigmatic disorder in the near future.

Hepatocyte growth factor may be involved in cellular changes to the peritoneal mesothelium adjacent to pelvic endometriosis

OBJECTIVE

To investigate the possible involvement of hepatocyte growth factor (HGF) in the cellular changes of pelvic mesothelium and the association of these changes with macrophage (Mphi) infiltration and the different stages of pelvic endometriosis.

DESIGN

Controlled clinical study using intact tissue.

SETTING

Nagasaki University School of Medicine, Nagasaki, Japan.

PATIENT(S)

Biopsy specimens from 25 red lesions, 20 black lesions of pelvic endometriosis and their adjacent peritoneum were excised either en bloc or separately during laparoscopy.

INTERVENTION(S)

Hepatocyte growth factor and activated macrophage-marker CD68 were immunolocalized using respective antibodies, and were quantitated by a computer analyzed quantitative-histogram (Q-H) score and light microscopy, respectively.

MAIN OUTCOME MEASURE(S)

The possible immunoreaction of HGF near the endometriotic lesions and their adjacent peritoneal mesothelium was examined. The association between immunostaining of HGF and macrophage infiltration around these cells was also investigated.

RESULT(S)

A fraction of biopsy specimens of pelvic peritoneum revealed histologically proven change from normal flat to cuboidal or columnar cell types. In cuboidal cells or flat cells of mesothelium adjacent to red lesions, the immunoreaction of HGF, as expressed by the Q-H scores, was found to be significantly higher than in corresponding cells adjacent to black lesions. The flat or cuboidal cells of pelvic mesothelium surrounding the red lesions also demonstrated greater macrophage infiltration than the cells surrounding black lesions. The Q-H scores of HGF in the cuboidal or columnar cells surrounding the red lesions showed a statistically significant correlation with the accumulation of macrophage in the cells; no similar correlation was demonstrated for black lesions.

CONCLUSION(S)

Adjacent peritoneum of pelvic endometriotic lesions may manifest an inflammatory response. Hepatocyte growth factor might be involved in the cellular changes found in the peritoneal mesothelium of women with pelvic endometriosis.

Future directions in endometriosis research

Future research in endometriosis must focus on pathogenesis studies in the baboon model, the early interactions between endometrial and peritoneal cells in the pelvic cavity at the time of menstruation, and potential differences between eutopic endometrium and myometrium in women with and without endometriosis. More integration is needed between the areas of epidemiology and genetics. Pelvic inflammation in women with endometriosis could be the target for new diagnostic and therapeutic approaches. Important questions remain regarding the relationship between endometriosis and environmental factors. Systemic and extrapelvic manifestations of endometriosis must be analyzed carefully, and better tools are needed to measure quality of life in women with chronic pain caused by endometriosis. Most current evidence supports a causal relationship between endometriosis and subfertility, and the spontaneous progressive nature of endometriosis has been demonstrated in 30% to 60% of patients. Recurrence of endometriosis after classic medical and surgical therapy is a major and underestimated problem, especially in women with advanced disease. Integrated clinical and research teams are needed that combine expert medical, surgical, and holistic care with state-of-the-art research expertise in immunology, endocrinology, and genetics to discover new diagnostic methods and medical treatments for endometriosis.

Immunoexpression of hepatocyte growth factor and c-Met receptor in the eutopic endometrium predicts the activity of ectopic endometrium

OBJECTIVE

To investigate the mitogenic and angiogenic activity of the eutopic and ectopic endometrium throughout the menstrual cycle and to examine whether the activity of the eutopic endometrium is useful to predict greater activity of the ectopic endometrium.

DESIGN

Controlled clinicopathologic study using intact tissue.

SETTING

Nagasaki University School of Medicine, Nagasaki, Japan.

PATIENT(S)

Fifteen infertile women with pelvic endometriosis and 10 women without endometriosis undergoing laparoscopy.

INTERVENTION(S)

Biopsies from the ectopic endometrium and the corresponding eutopic endometrium were collected. Immunohistochemical staining was performed using respective antibodies, and a computer analyzed modified quantitative-histogram (Q-H) score was used to quantify immunostaining.

MAIN OUTCOME MEASURE(S)

The immunoreactions of hepatocyte growth factor (HGF), its receptor, c-Met, vascular endothelial growth factor (VEGF), proliferating cell nuclear antigen (PCNA), and von Willebrand factor (VWF) in eutopic and ectopic endometrium were examined, and their relation with different revised American Society for Reproductive Medicine (r-ASRM) stages and the morphology of endometriosis was evaluated.

RESULT(S)

The immunoexpressions of HGF and c-Met were significantly higher in the eutopic endometrium of patients with endometriosis than in that of controls. The Q-H scores of HGF, c-Met, VEGF, PCNA, and microvessel density (MVD) were markedly higher in red peritoneal lesions when compared with other lesions. The Q-H scores did not reveal r-ASRM stage-dependent variation in any of these markers. We observed a significant correlation between the immunoexpressions of HGF, c-Met, and PCNA or microvessel counts. When we combined the Q-H scores of the glandular epithelium and stroma, we found that increased activity of the eutopic endometrium as measured by the immunoreaction of HGF, c-Met, VEGF, PCNA, and MVD was similar to highly active red lesions and was significantly higher than that of controls and other lesions.

CONCLUSION(S)

Immunoexpression of HGF and c-Met in the eutopic endometrium of patients with pelvic endometrioisis is possibly useful to predict greater activity of the ectopic endometrium.

The molecular basis for implantation failure in endometriosis: on the road to discovery

Endometriosis is a benign gynecologic disorder associated with pelvic pain and infertility, with the latter being due, in part, to failure of embryonic implantation in the maternal endometrium. Adequacy of the endometrium for fertility has been classically investigated by histologic evaluation of a mid-late luteal phase biopsy and, historically, normal histology has been reassuring. However, recent studies demonstrate histologically normal, but biochemically abnormal, endometrium during the window of implantation in some women with endometriosis. In the pregenomic era, a "one-by-one" approach has been adopted to investigate proteins and genes expressed in the window of implantation, and several genes or gene products have been found to be aberrantly expressed in endometrium of women with endometriosis either during the implantation window or at other times of the cycle. Some of these are related to failure of implantation, while others likely contribute to the establishment and growth of endometriotic lesions. The time has come for a genome-wide approach to evaluate uterine endometrium for embryonic implantation. Knowing the biochemical mechanisms underlying normal implantation and the abnormalities in endometriosis will facilitate development of new diagnostic criteria beyond histologic evaluation and will permit identification and validation of molecular targets for future drug discovery. This monograph reviews (a) some of the evidence of compromised fertility in women with endometriosis and treatments targeted to improve their fertility; (b) the concept of the window of implantation; (c) genes/gene products aberrantly expressed in endometrium during the window of implantation or other times of the cycle in women with endometriosis; and (d) the use of microarray technology to investigate endometrial gene expression in human endometrial stromal cells and preliminary data resulting from a collaborative consortium effort of a genome-wide investigation of gene expression in the window of implantation of women with versus without endometriosis.

Expression and action of hepatocyte growth factor in bovine endometrial stromal and epithelial cells in vitro

Hepatocyte growth factor (HGF) is a pleiotropic growth factor that acts on various epithelial cells. The objectives of this study were to determine whether HGF altered the proliferation and prostaglandin (PG) secretion of bovine endometrial stromal and epithelial cells in vitro. We also observed HGF and HGF receptor (c-met) mRNA expression in cultured bovine endometrial stromal and epithelial cells by RT-PCR. Stromal and epithelial cells obtained from cows in early stage of the estrous cycle (days 2-5) were cultured in DMEM/Ham's F-12 supplemented with 10% calf serum. The cells were exposed to HGF (0-10 ng/ml) for 2, 4, or 6 days. HGF significantly increased the total DNA in epithelial (P < 0.05), but not stromal cells. In another experiment, when the cells reached confluence, the culture medium was replaced with fresh medium with 0.1% BSA containing HGF 0-100 ng/ml and the cells were cultured for 24 hr. The HGF stimulated PGF2alpha secretion in epithelial, but not stromal cells. RT-PCR revealed that mRNA of HGF is expressed only in stromal cells, and that c-met mRNA is expressed in both stromal and epithelial cells. These results suggest that HGF plays roles in the proliferation and the regulation of secretory function of bovine endometrial epithelial cells in a paracrine fashion.

Endometrial anomalies in women with endometriosis

Endometriotic lesions are defined by extrauterine growth of endometrial glands and stroma. Retrograde menstruation with subsequent attachment, invasion, and neovascularization are believed to give rise to the endometriotic lesions. As most women exhibit some degree of retrograde menstruation, some other unidentified factor(s) must render certain women susceptible to attachment and growth of ectopic endometrial tissue. A variety of theories have been proposed to account for this susceptibility, including genetic predisposition, aberrant immunological response, and an altered peritoneal environment. Ectopic endometriotic lesions are histologically similar to their putative eutopic precursors, yet significant biochemical differences exist between these two tissues. Less information is available regarding differences between eutopic endometrium from women with or without endometriosis. This report describes anomalies in structure, proliferation, immune components, adhesion molecules, proteolytic enzymes and inhibitors, steroid and cytokine production and responsiveness, and gene expression and protein production that have been identified in eutopic endometrium from women with endometriosis.

Theories of endometriosis

Endometriosis is characterised by the presence of abnormally located tissue resembling the endometrium with glands and stroma. Several hypotheses have attempted to explain the development of such tissue. The oldest theory, that of metaplasia, suggests that under diverse influences coelomic tissue could be transformed into endometrium. The most often cited theory, that of implantation, proposes that the physiological phenomenon of endometrial reflux in the fallopian tubes during menstruation may, in certain conditions, overcome local defense mechanisms, implant, and proliferate. The peritoneal fluid in unaffected women possesses the capacity to prevent endometriotic tissue from becoming established. The reasons for the occurrence of endometriosis and its consequences (pain, sterility, adhesions) are probably numerous and involve the endometrium, the immune system (macrophages, natural killer cells), the peritoneum, and fallopian tubes. The failure to clear the peritoneal cavity of fragments of endometrium could cause a state of local inflammation with hyperactivation of macrophages secreting a variety of different compounds. Some of these compounds may bring about metaplasia of the peritoneum or the development of Mullerian residues.

Is endometriosis an endometrial disease?

Endometriosis is characterised by the presence of abnormally located tissue resembling the endometrium with glands and stroma. Several hypotheses have attempted to explain the development of such tissue. The most often cited theory, that of implantation, proposes that the physiological phenomenon of endometrial reflux in the fallopian tubes during menstruation may, in certain conditions, overcome local defense mechanisms, implant, and proliferate. The implantation theory does not explain why endometriosis will develop only in approximately 10-15% of women, while the reflux of endometrial tissue via the fallopian tubes during menstruation is a quasi-universal phenomenon. The endometrium of women affected by endometriosis could be abnormal compared with endometrium of healthy women. The abnormal endometrium could be able to protect itself from harmful effects of immune cells by expressing specific antigens, by harbouring a different immune cell population and by synthetizing and secreting immunosuppressive factors. Several others characteristic features of endometrium have been described in women with endometriosis: (1) production of its own estrogens in too heavy amount; (2) aptitude for setting up on peritoneum; (3) tendencies to proliferate and to invade tissue; (4) aggressiveness for the peritoneum; (5) auto-protection from physiological apoptosis; (6) abnormal expression of heat shock proteins; and (7) excessive angiogenesis.

Hepatocyte growth factor in human milk and reproductive tract fluids

PROBLEM

Despite evidence indicating a role for hepatocyte growth factor (HGF) in gastrointestinal and reproductive physiology, the concentration and distribution of HGF in human breast milk (BM) and reproductive tract fluids remain unknown.

METHOD OF STUDY

Using enzyme-linked immunosorbent assay (ELISA), the HGF concentrations were determined in human oviductal fluid (hOF), follicular fluid (FF), amniotic fluid (AF), seminal plasma (SP), and colostrum/milk samples, and expression of HGF mRNA by milk cells and AF cells were examined by reverse transcriptase-polymerase chain reaction (RT-PCR).

RESULTS

HGF is present at nearly 70-fold normal serum (0.85+/-0.15 ng/mL) concentration in FF (n = 3; x = 57+/-16 ng/mL) and AF (n = 17; x = 57+/-26 ng/mL), and is also present in hOF (n = 3; x = 4.8+/-2.3 ng/mL) and CVL (n = 8; x = 0.7+/-1.1 ng/mL) varying throughout the menstrual cycle. HGF is found at 3-times serum concentration in BM (n = 24; x = 2.3+/-1.3 ng/mL) with no significant difference between premature and full term or stage of lactation (colostrum, transitional, mature milk). HGF mRNA was detected in BM cells but not in AF cells.

CONCLUSIONS

HGF is present in sufficient amounts to profoundly affect gastrointestinal maturation in the fetus via swallowed AF and neonate via BM, and helps to explain the increased rate of necrotizing enterocolitis (NEC) in infants of premature rupture of membrane (PROM)-complicated pregnancies, and the decreased rate in breast fed neonates. HGF in FF may be necessary for the development and maturation of the oocyte. HGF in hOF, SP, and cervicovaginal lavage (CVL) is likely to enhances epithelial cell integrity and the mucosal barrier. Thus, HGF is widely available in the reproductive tract with functions that remain to be fully elucidated.

Hepatocyte growth factor concentrations are elevated in peritoneal fluid of women with endometriosis

The concentrations of hepatocyte growth factor (HGF) in peritoneal fluid (PF) from women with endometriosis (n = 36) and without endometriosis (n = 40) were measured. All of the PF samples examined contained detectable concentrations of HGF. The HGF concentrations in PF from women with stage III/IV endometriosis (0.906 ng/ml, 0. 561-1.185; median, interquartile range) were significantly higher (P < 0.0001) than those from women without endometriosis (0.315 ng/ml, 0.251-0.472). The HGF concentrations from women with stage I/II endometriosis (0.417 ng/ml, 0.310-1.023) appeared to be intermediate. There were no apparent variations detected among the HGF concentrations in women in the follicular or luteal phases regardless of the presence of endometriosis. Interestingly, HGF concentrations in PF from women on gonadotrophin releasing hormone analogues, independent of the presence of endometriosis, were comparable with those from untreated women. Given the known mitogenic property of HGF in human endometrial cells, these results suggest that HGF might play a role in the progression of endometriosis.

Expression of hepatocyte growth factor in cultured human endometrial stromal cells is induced through a protein kinase C-dependent pathway

To examine the production of hepatocyte growth factor (HGF) by human endometrial stromal cells (ESC) in vitro, concentrations of HGF in the culture media of ESC were measured after the addition of various amounts of 12-O-tetradecanoylphorbol 13-acetate (TPA), forskolin, lipopolysaccharide (LPS), interleukin (IL)-1beta, IL-6, IL-8, tumor necrosis factor alpha (TNFalpha), interferon-gamma (IFNgamma), or ethynylestradiol-17alpha using an ELISA. The expression of HGF mRNA was also assayed by a reverse transcription-polymerase chain reaction. The concentration of HGF in the culture media of unstimulated ESC was below the detection level of the assay. TPA stimulated the secretion of HGF by ESC in a dose-dependent manner. TPA also induced the transcription of HGF mRNA by ESC. Forskolin, LPS, IL-1beta, IL-6, IL-8, TNFalpha, IFNgamma, or ethynylestradiol-17alpha did not alter HGF mRNA or protein levels. TPA-stimulated production of HGF was partially inhibited by the addition of 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine or sphingosine. These results suggest that a protein kinase C-dependent pathway may play an important role in the regulation of HGF production by ESC. HGF secreted by ESC may be involved in the regeneration of the endometrium during the normal menstrual cycle.

Endometriosis: abnormal endometrium and dysfunctional immune response

This review highlights recent studies that illuminate the role of the immune system in endometriosis. The findings are discussed in the framework of a model which proposes that endometriosis reflects an immunological selection process. Endometrial cells, which are inherently resistant to apoptosis and immune-mediated elimination, acquire the capacity to utilize the products of an activated immune system to establish ectopic foci of disease. Cyclical inflammatory/immune cell stimulation that fails to eliminate ectopic endometrial implants results in progressive immunological derangement and associated pathophysiological changes which are characteristic of the disease.