Endometrial Progesterone Receptor Expression Research Articles

MON-006 Progesterone Receptor Expression in Endometrial Biopsies After 12 Weeks of Exposure to A 4-µg E2 Softgel Vaginal Insert or Placebo

The softgel, vaginal 17β-estradiol (E2) insert (TX-004HR) significantly improved the maturation index of the vaginal epithelium, dyspareunia and vaginal dryness in menopausal women with vulvar and vaginal atrophy (VVA) and moderate to severe dyspareunia, without histological changes to the endometrium (Constantine G et al, Menopause 2017;24:409-416). The 4-μg and 10-μg E2 doses were FDA approved as Imvexxy® (TherapeuticsMD, Boca Raton, FL), for the treatment of moderate to severe dyspareunia, a symptom of VVA, due to menopause. The progesterone receptor (PR) is an estrogen-regulated gene with expression that is very sensitive to E2 exposure (Xiao CW and Goff AK, J Reprod Fertil.1999;115:101-109). Endometrial PR expression in the biopsies of women using the softgel vaginal 4-µg E2 insert was used as a marker of E2 exposure to determine whether sufficient E2 applied with the vaginal insert reaches the endometrium to upregulate PR expression. Our hypothesis posits that there would be insufficient E2 from the 4-µg E2 insert to stimulate an increase in endometrial PR expression.In this post hoc analysis of the REJOICE trial, endometrial biopsies from 25 women who had a normal baseline biopsy, an on-therapy biopsy after study day 70, and tissue readings from all pathologists were randomly selected from the 4-µg E2 vaginal insert and placebo groups. Endometrial tissue sections were stained to visualize PR expression using PgR1294 (Agilent; Santa Clara, CA). Cell staining was quantified using a trainable feature-recognition algorithm and mean expression levels between baseline and week 12 were analyzed by 2-sided t-tests.Acceptable PR expression results were available for 22 women in the 4-µg E2 group (three had insufficient tissue for analysis) and 25 women in the placebo group. For the 4-µg E2 group, mean ± SD (pmol/mg) PR expression was 0.455 ± 0.203 at baseline and 0.506 ± 0.226 at week 12. For the placebo group, mean PR expression was 0.579 ± 0.196 at baseline and 0.563 ± 0.213 at week 12. Mean PR expression levels at baseline and week 12 were not significantly different from each other within the 4-µg E2 (P=0.438) or placebo (P=0.783) group.No meaningful difference in endometrial PR expression was observed with the vaginal 4-µg E2 insert at week 12. These data support our hypothesis and the assertion that low-dose, local vaginal E2 exposure with the insert placed in the lower part of the vagina, does not pose an endometrial safety issue in postmenopausal women.

193 Melatonin implants in spring improve embryo production of aged ewes after superovulation regardless of endometrial progesterone receptor expression

Twenty-three Rasa Aragonesa aged ewes (average age: 10.3±0.3 years) were used to determine the effect of melatonin on ovulatory response, embryo production, and endometrial expression of progesterone receptors (PR) after superovulation. Ewes were treated (M, n=13) or not (control, C, n=10) with melatonin implants in March (Day 0, Northern Hemisphere autumn), and received intravaginal progestogen sponges for 14 days on Day 77. Superovulatory treatments consisted of 8 doses in decreasing concentrations (2 mL×2 and 1 mL×6) of 176 NIH-FSH-S1 units of NIADDK-oFSH-17 (Ovagen, ICPbio Reproduction, Auckland, New Zealand) administered twice daily starting 72h before sponge removal. Seven days after oestrus, embryos were recovered by laparotomy, ewes were killed, and uterine horns were processed to study PR expression by immunohistochemistry. The amount of PR was estimated subjectively by 2 independent observers in 5 endometrial compartments: luminal epithelium (LE), superficial (sGE) and deep (dGE) glandular epithelia, and superficial (sS) and deep (dS) stroma. The extent of staining was expressed on a scale from 0 to 100. Data were analysed with a 2×2 factorial ANOVA. Melatonin implants improved fertilization (92v. 57%, for M and C groups, respectively; P<0.01), blastocyst (47v. 9%; P<0.01), viability (88v. 31%; P<0.0001), and freezability (69v. 21%; P<0.001) rates. Specifically, melatonin induced a significant reduction of the number of non-viable (degenerate and retarded) embryos (0.3v. 1.5; P<0.05) and increased blastocysts (2.8v. 0.8; P<0.05) per ewe. Melatonin treatment decreased PR staining intensity (47v. 55%; P<0.05), but this effect was not observed when the individual cell types were compared (Table 1). Because the number of corpora lutea (CL) was responsible for different PR expression in both groups (P<0.0001), animals were divided into 2 ovulation rate categories: <10 CL and ≥10 CL, with lesser PR expression in the ≥10 CL group (P<0.0001); this lower PR immunostaining in ≥10 CL is consistent with progesterone down-regulation of its own receptor. An interaction among number of CL and treatment was found for embryo quality (P<0.05); thus, the positive effect of melatonin on this parameter was particularly effective in the low-ovulation-rate group. These results demonstrate that melatonin treatment in the autumn improves embryo quality in aged ewes, and that this effect is not explained by a differential endometrial sensitivity to progesterone. Table 1.Embryo production (mean±s.e.m.) in melatonin-treated (M) and control (C) ewes after superovulation in autumn, and staining intensity of progesterone receptors in the endometrium (CL=corpora lutea)

Unexplained infertility patients present the mostly impaired levels of progesterone receptors: Prospective observational study

Τo assess the endometrial expression of progesterone receptors in various subgroups of infertile women during implantation window. ΜETHODS: A prospective observational study was performed during March 2013-February 2017. Infertile women were categorized to those with tubal factor, ovarian failure, endometriosis or unexplained infertility. Endometrial biopsy was obtained on 7th-8th postovulatory day. Total progesterone receptors' PR(A+B) and type-B receptors' (PR-B) expression were compared between all categories of infertile and fruitful controls. There were overall 30 patients with tubal factor infertility (group 1), 30 with ovarian failure (group 2), 20 with endometriosis (group 3) and 20 with unexplained infertility (group 4). The control group consisted of 30 fertile patients. Patients with unexplained infertility presented the lowest levels of epithelial endometrial expression both regarding PR(A+B) and PR-B receptors. PgR(A+B) h-score in luminal epithelial cells was 106.4±14.7 for cases with unexplained infertility vs 219.7±15.8 for controls (P<.001). Similarly, PgR(A+B) h-score in glandular epithelial cells was 109.7±13.9 vs 220.1±17.2 (P<.001). Relative remarks were made for type-B progesterone receptors. Εndometrial expression of progesterone receptors is impaired in women with unexplained infertility. Therapeutic strategies targeting on improving progesterone receptors' expression may significantly affect final reproductive outcome.

Androgens Upregulate Endometrial Epithelial Progesterone Receptor Expression: Potential Implications for Endometriosis

Androgenic compounds have been implicated in induction of endometrial atrophy yet the mechanisms of androgen effects on human endometrium have not been well studied. We hypothesized that androgens may promote their endometrial effects via modulation of progesterone receptor (PR) expression. Proliferative phase endometrial samples were collected at the time of hysterectomy. We evaluated the effect of the potent androgen 5α-dihydrotestosterone (DHT) on endometrial PR expression by treating human endometrial explants, endometrial stromal cells, and Ishikawa cells with DHT. Ishikawa cells were also treated with DHT ± the androgen receptor (AR) blocker flutamide. The PR-B, total PR messenger RNA (mRNA), and PR protein expression were assessed. Expression of cyclin D1 and D2 was checked as markers of cell proliferation. As expected, estradiol induced PR expression in isolated stromal cells, endometrial epithelial cells, and tissue explants. The DHT treatment also resulted in increased PR expression in endometrial explants and Ishikawa cells but not in stromal cells. Further, protein levels of both nuclear PR isoforms (PR-A and PR-B) were induced with the DHT treatment. Although flutamide treatment alone did not affect PR expression, flutamide diminished androgen-induced upregulation of PR in both endometrial explants and Ishikawa cells. Although estradiol induced both cyclin D1 and cyclin D2 mRNA, DHT did not induce these markers of cell proliferation. Androgens may mediate endometrial effects through upregulation of PR gene and protein expression. Endometrial PR upregulation by androgens is mediated, at least in part, through AR.

Endometrial expression of progesterone receptors but not avb3 integrins is significantly decreased in women with unexplained infertility and poor ovarian reserve

Endometrial expression of progesterone receptors but not avb3 integrins is significantly decreased in women with unexplained infertility and poor ovarian reserve

Effect of nutrition on endometrial progesterone receptor expression in ewes

It has been postulated that undernourishment could affect embryo survival through changes in the uterine environment (Abecia et al., 1995). Moreover, we have shown that undernourished ewes had higher plasma progesterone (P4) concentrations and a lower endometrial content of P4 (Lozano et al., 1998), suggesting that this lower endometrial content could be due to a decrease in the content of endometrial progesterone receptors (PR). The aim of this study was to investigate the effect of low and high levels of food intake on PR in different endometrial cell types.

Endometrial progesterone receptor expression during the human menstrual cycle.

The human endometrium undergoes regular cyclical changes under the endocrine control of oestrogens and progesterone acting via specific nuclear receptors. The molecular and cellular events mediating these changes are not understood. The present study examined the changes in the endometrial progesterone receptor and its mRNA during the menstrual cycle. Forty-four endometrial samples obtained from women with normal menstrual cycles were divided into four categories: early proliferative (days 6-9), late proliferative (days 10-14), early secretory (days 15-21) and late secretory (days 22-28). The progesterone receptor protein was determined using a human progesterone receptor enzyme-linked immunoassay kit. Total RNA was extracted using RNAzol and the abundance of mRNA encoding the progesterone receptor was determined by reverse transcriptase-polymerase chain reaction and by northern blot analysis. The concentration of the progesterone receptor in the endometrium was highest during the late proliferative phase and was lowest in the late secretory phase. Significant differences were observed between the menstrual cycle phases (P < 0.003). No cyclical variation was observed in the concentration of mRNA encoding for the progesterone receptor in the endometrium when analysed by reverse transcriptase polymerase chain reaction or by northern analysis. There appears to be no association between the amounts of mRNA encoding the progesterone receptor and progesterone receptor protein during the menstrual cycle suggesting that the control of the expression of the progesterone receptor may not occur solely at the transcriptional level.