Endometrial expression of steroid receptors in postmenopausal hormone replacement therapy users: relationship to bleeding patterns.

BACKGROUND: Mechanisms of menopausal hormone replacement therapy (HRT)-related bleeding, undoubtedly mediated through endometrial steroid receptors, are poorly understood. We aimed to determine the steroid receptor expression in HRT-exposed endometrium in relation to disturbances of bleeding patterns. METHODS: Prospective observational study in a tertiary referral menopause clinic in Western Australia. Thirty-eight outpatient endometrial biopsies (seven from women not on HRT, 31 from HRT users) were collected from 21 postmenopausal women during and outside bleeding episodes. Eleven women provided multiple biopsies. We performed an immunohistochemical analysis of endometrial glandular, stromal, epithelial, perivascular and endothelial expression of progesterone receptor (PR), glucocorticoid receptor (GR), androgen receptor (AR), estrogen receptors alpha and beta (ERalpha and ERbeta) and studied their relationship to bleeding patterns. RESULTS: In HRT users, during a bleeding episode, there was a trend (non-significant) towards a decrease in PR and an increase in GR in endometrial glandular cells. No differences were observed in AR and ER expression. CONCLUSIONS: We have been unable to demonstrate significant differences in steroid receptor expression in endometrium of women using HRT who report unscheduled bleeding episodes. These observations differ from the endometrial steroid receptor expression observed with normal menstruation and long-term progestogen-only administration, suggesting that different local mechanisms are involved in HRT-related unscheduled bleeding.

Mid-luteal endometrial intracrinology following controlled ovarian hyperstimulation involving use of a gonadotrophin releasing hormone antagonist.

BACKGROUND: There are concerns of reduced pregnancy rates with the use of gonadotrophin-releasing hormone antagonists (GnRH antagonists) in IVF/ICSI cycles. Sex steroids and their metabolizing enzymes in the endometrium may play a vital role in embryo implantation. This study has evaluated the levels and localization of sex-steroid receptors and metabolizing enzymes, 3beta-hydroxysteroid dehydrogenases (3betaHSD) and selected 17beta-HSD (17betaHSD), in mid-luteal endometrium of women treated with GnRH antagonist (Cetrorelix) and recombinant FSH (rFSH; Gonal-F) with luteal phase progesterone supplementation. METHODS: Mid-luteal phase endometrial biopsies were obtained from oocyte donors undergoing ovarian stimulation and from control women with regular periods. Immunohistochemistry and real-time quantitative-polymerase chain reaction (QRT-PCR) were used to compare protein and mRNA expression of progesterone receptor (PR), estrogen receptor alpha (ERalpha), estrogen receptor beta (ERbeta), androgen receptor (AR), 3betaHSD1, 3betaHSD2, 17betaHSD2 and 17betaHSD5. RESULTS: Cetrorelix-rFSH treatment caused a mid-luteal suppression of PR protein expression in the endometrial stroma, surface epithelium and glands, although expression in the glands of control samples was variable. In contrast, the treatment caused an increase in PR staining in perivascular cells. No other significant differences in protein expression were observed between the two groups. mRNA levels of AR, ERalpha, 3betaHSD1 and 17betaHSD2 were significantly reduced in the treatment group. PR mRNA levels were also reduced by GnRH antagonist-rFSH treatment, but the difference was not significant. CONCLUSIONS: Changes in the expression of sex-steroid receptors and metabolizing enzymes may lead to alterations in the activity and intracellular availability of estrogens, progestogens and androgens in endometrium of women treated with Cetrorelix and rFSH. Their impact on embryo implantation merits further evaluation.

Intrauterine release of progesterone antagonist ZK230211 is feasible and results in novel endometrial effects: a pilot study.

BACKGROUND: Continuous administration of progesterone antagonists (PAs) results in endometrial suppression and amenorrhoea in several model systems. We compared the effects of intrauterine release of a highly specific PA, ZK230211, to those of a progestin using the levonorgestrel-releasing intrauterine system (LNG-IUS). METHODS: Forty-two women were randomly fitted with an IUS releasing either ZK230211 at a rate 1, 4 or 8 microg/24 h (ZK-IUS) or LNG (at 20 microg/24 h, LNG-IUS) at 4-8 weeks before hysterectomy. Bleeding patterns, endometrial morphology and content of ZK230211, and various immunohistochemistries (IHCs) were evaluated. RESULTS: Days of bleeding and spotting were unchanged by the use of ZK-IUSs but were increased by LNG-IUS (P < 0.01). ZK230211 was measurable in all endometrial specimens. Endometrium was partly suppressed in 9-30% of women following the use of ZK-IUSs, and in 67% after LNG-IUS. IHCs for Ki-67 and phosphorylated histone H3 were not suggestive of proliferative activity in any group. Compared to LNG, progesterone receptor (PR) was increased following ZK230211 in surface epithelium (all three doses P < 0.01-P < 0.05) and stroma at 4 microg/24 h (P < 0.05). Although low, androgen receptor staining was higher in endothelial epithelium following LNG than ZK230211 (P < 0.05). Insulin-like growth factor-binding protein-1 (IGFBP-1) was detectable only following LNG (P < 0.0001). CONCLUSIONS: Short-term intrauterine release of ZK230211 did not change bleeding patterns or result in endometrial suppression. Expression of proliferation markers was low following the use of both IUSs. Absence of IGFBP-1 and increase in PR reflect the PA effects of ZK230211.