Culture characteristics of human endometrial glandular epithelium throughout the menstrual cycle: modulation of deoxyribonucleic acid synthesis by 17 beta-estradiol and medroxyprogesterone acetate

A mechanically robust and stable estradiol-loaded PHEMA-based hydrogel barrier for intrauterine adhesion treatment

Estrogen combined with physical barrier therapy may be a prospective method to repair a damaged endometrium and prevent postsurgical re-adhesion in the treatment of intrauterine adhesions (IUAs), but there lacks a suitable scaffold with good biocompatibility, appropriate mechanical properties, and drug-releasing kinetics. Herein, a mechanically robust and stable barrier based on the poly(hydroxyethyl methacrylate) (PHEMA) hydrogel combined with estradiol-loaded mesoporous silica is designed. The network is formed by covalent bonds and noncovalent coordination bonds, which endow the hydrogel with superior mechanical properties to most reported PHEMA-based hydrogels. Meanwhile, the covalent bonds impart excellent stability to the hydrogel, which maintains its structure and mechanical properties in a simulated uterine fluid for 30 days. The excellent mechanical properties and stability are comparable to those of a typical barrier material intrauterine device (IUD), enabling the hydrogel to be retained in the uterus and removed intact like an IUD. In vitro and in vivo experiments show that the hydrogel possesses good biocompatibility similar to pure PHEMA hydrogels. In addition, the hydrogel releases estradiol continuously and stably, and exhibits a good therapeutic effect in promoting the proliferation of endometrial cells and inhibiting the progression of fibrosis. Therefore, the combinational advantages make the present hydrogel very promising in IUA treatment.

Menstrual cyclic change of metastin/GPR54 in endometrium

Metastin/kisspeptin is encoded by KISS1 and functions as an endogenous ligand of GPR54. Interaction of metastin with GPR54 suppresses metastasis and also regulates release of gonadotropin-releasing hormone, which promotes secretion of estradiol (E2) and progesterone (P4). We have previously demonstrated epigenetic regulation of GPR54 in endometrial cancer and the potent role of metastin peptides in inhibiting metastasis in endometrial cancer. However, little is known about how the metastin-GPR54 axis is regulated in the endometrium, the precursor tissue of endometrial cancer. Endometrial stromal cells (ESCs) and endometrial glandular cells (EGCs) within the endometrium show morphological changes when exposed to E2 and P4. In this study, we show that metastin expression is induced in ESCs through decidualization, but is repressed in glandular components of atypical endometrial hyperplasia (AEH) and endometrial cancer relative to EGCs. The promoter of GPR54 is unmethylated in normal endometrium and in AEH. These results indicate metastin may function in decidualized endometrium to prepare for adequate placentation but this autocrine secretion of metastin is deregulated during oncogenesis to enable tumor cells to spread.

Androstenedione up-regulation of endometrial aromatase expression via local conversion to estrogen: potential relevance to the pathogenesis of endometriosis

CONTEXT

Up-regulation of aromatase expression in endometrial cells disseminated into the peritoneal cavity may enhance their survival via local estrogen synthesis, which may lead to endometriosis. The factors that mediate induction of aromatase in the endometrium are not well defined, but increased expression of steroidogenic factor (SF)-1 may play a role.

OBJECTIVE

The objective of the study was to determine whether androstenedione (A4), the predominant sex steroid in peritoneal fluid, regulates endometrial aromatase expression.

DESIGN

This was a cell/tissue culture study.

SETTING

The study was conducted at an academic center.

METHODS

Quantitative real-time PCR, HPLC, and chromatin immunoprecipitation were used in this study.

RESULTS

Treatment of cultured human endometrial explants and stromal cells with A4 (10 nm) significantly up-regulated expression of aromatase mRNA transcripts containing exon IIa at their 5'-ends. In endometrial stromal cells and the human endometrial surface epithelial (HES) cell line, induction of aromatase mRNA by A4 was associated with increased expression of SF-1. In HES cells, tritiated A4 was metabolized to estradiol, testosterone (T), dihydrotestosterone, and androstanediol. Both estradiol and T, but not nonaromatizable androgens, up-regulated aromatase and SF-1 mRNA in HES cells. Chromatin immunoprecipitation revealed that A4 enhanced recruitment of SF-1 to its response element (-136 bp) upstream of CYP19 exon IIa. This, together with the findings that both estrogen receptor antagonist, ICI 182,780, and aromatase inhibitor, fadrozole, suppressed A4 and T induction of aromatase and SF-1 mRNA, indicates that the inductive effects of A4 and T are mediated by their conversion to estrogens.

CONCLUSIONS

Exposure of endometrial cells to A4 may enhance CYP19 gene expression through its aromatization to estrogens.

A novel organotypic culture model for normal human endometrium: regulation of epithelial cell proliferation by estradiol and medroxyprogesterone acetate

BACKGROUND

A novel organotypic culture system was established for modelling the hormonal responses of the normal human endometrium in vitro.

METHODS

Endometrial epithelial cells were cultured as glandular organoids within reconstituted extracellular matrix (Matrigel) in tissue culture inserts and stromal cells on plastic below the epithelial compartment. The effects of estradiol (E2) and E2 together with medroxyprogesterone acetate (MPA) on cell proliferation and the expression of estrogen receptor alpha (ERalpha) and progesterone receptor (PR) were studied in 10 epithelial-stromal co-cultures and in three parallel monocultures of epithelial organoids.

RESULTS

In co-cultures, E2 was shown to increase the percentage of Ki67-positive cells by approximately 2-fold relative to untreated controls. In the presence of MPA, a significant decrease in cell proliferation was detected. Similar results were obtained when the corresponding percentages of Ki67-positive organoids were calculated instead of individual cells. In the absence of stromal fibroblasts, Ki67 epithelial labelling remained below the control value after both hormonal treatments. Epithelial organoids retained their capacity to express estrogen and progesterone receptors in culture. E2 was shown to markedly increase and MPA to down-regulate the expression of PR. The expression of ERalpha was only slightly affected by either hormonal treatment.

CONCLUSIONS

The present organotypic model provides a novel in vitro system in which to study the effects of steroids in the normal human endometrium both in terms of cell proliferation and gene expression. The culture system holds promise as a useful method to screen novel steroid compounds and may help to circumvent problems related to the use of animal models.

Regression of endometrial hyperplasia after treatment with the gonadotrophin-releasing hormone analogue triptorelin: a prospective study

Endometrial hyperplasia is thought to be caused by the prolonged, unopposed oestrogenic stimulation of the endometrium. The regression of hyperplastic back to normal endometrium is the main purpose of any conservative treatment in order to prevent development of adenocarcinoma. The aim of this study was to evaluate the regression of hyperplastic to normal endometrium in patients with various forms of endometrial hyperplasia after treatment with the gonadotrophin-releasing hormone analogue (GnRHa) triptorelin for 6 months. Fifty-six patients with endometrial hyperplasia were enrolled in this trial; 39 patients (group I) presented simple hyperplasia, 14 (group II) complex hyperplasia and three (group III) atypical complex hyperplasia. All patients were treated with triptorelin for 6 months. Bleeding control during treatment was excellent. A post-treatment curettage for estimation of endometrial histology was performed on 54 out of 56 patients 100.1 +/- 44.7 days after the last triptorelin dose, following the restoration of pituitary function. Regression of hyperplastic to normal endometrium was observed in 32 (86.5%) out of 37 patients in group I and in 12 (85.7%) out of 14 in group II. Persistence of simple hyperplasia was found in five (14.5%) out of 37 patients in group I. Persistence of complex hyperplasia was found in 1 (7.1%) out of 14 patients and progression to atypical complex hyperplasia in another one (7.1%) woman in group II. In some of these cases, the presence of risk factors such as obesity, diabetes mellitus and ovulatory disturbances may contribute to the disease persistence despite therapy. On the other hand, in group III, none of the three patients had normal post-treatment endometrial histology. It seems, therefore, that in cases of endometrial hyperplasia without atypia, the administration of the GnRHa triptorelin is associated with high regression rates to normal endometrium. Conversely, the presence of atypia seems to be a poor prognostic factor. Treatment tolerance and bleeding control during therapy is excellent.

Expression of transforming growth factor-beta 1 messenger ribonucleic acid and the modulation of deoxyribonucleic acid synthesis by transforming growth factor-beta 1 in human endometrial cells

OBJECTIVE

The purpose of this study was (1) to evaluate the potential sites of transforming growth factor-beta 1 synthesis in human endometrium by analyzing separated endometrial glands and stromal cells for transforming growth factor-beta 1 messenger ribonucleic acid by Northern analysis of total ribonucleic acid and (2) to investigate the effects of transforming growth factor-beta 1 on deoxyribonucleic acid synthesis in endometrial epithelial and stromal cells in culture.

STUDY DESIGN

Endometrial glands and stroma from proliferative and secretory endometrium were isolated after collagenase treatment of endometrial tissue minces and were analyzed for transforming growth factor-beta 1 messenger ribonucleic acid by Northern analysis. We studied the effects of estradiol-17 beta and transforming growth factor-beta 1 on deoxyribonucleic acid synthesis in endometrial epithelium and transforming growth factor-beta 1 on stromal cells in culture by evaluating tritiated thymidine incorporation into trichloroacetic acid-precipitable material.

RESULTS

Transforming growth factor-beta 1 messenger ribonucleic acid was detected for Northern analysis in separated endometrial stromal cells in levels that were greatest during the secretory phase and in greater levels than in epithelial cells from that same tissue. Transforming growth factor-beta 1 messenger ribonucleic acid in glandular epithelium in culture was not increased to detectable levels by treatment with transforming growth factor-beta 1. Deoxyribonucleic acid synthesis in endometrial glandular epithelium was inhibited by transforming growth factor-beta 1, but transforming growth factor-beta 1 stimulated deoxyribonucleic acid synthesis in endometrial stromal cells in culture. After treatment for 5 days with estradiol-17 beta (10(-8) mol/L), deoxyribonucleic acid synthesis in endometrial glands in culture was decreased by 40%. Transforming growth factor-beta 1 (1 ng/ml) did not alter this effect of estradiol-17 beta on deoxyribonucleic acid synthesis.

CONCLUSIONS

Transforming growth factor-beta 1 acts to decrease deoxyribonucleic acid synthesis in epithelial cells and to increase it in stromal cells isolated from human endometrium and maintained in monolayer culture. Transforming growth factor-beta 1, potentially of stromal cell origin, could participate in the regulation of endometrial cell proliferation and differentiation in vivo.