Estrogen receptor (ER) and ER-related receptor expression in normal and atrophic human vagina

Endometrial safety of low-dose vaginal estrogens

ABSTRACT

It is estimated that up to 50% to 90% of postmenopausal women may experience genitourinary syndrome of menopause (GSM), which may have a detrimental impact on quality of life. One of the most effective modes of treatment of GSM is low-dose vaginal estrogens. Numerous studies have addressed the safety of these estrogens using endometrial biopsy and/or endometrial thickness on ultrasound. Based on these studies, the consensus is that low-dose vaginal estrogens do not substantially increase the risk of endometrial hyperplasia or cancer; however, the data are severely limited by short duration of follow-up. Although long-term trials are warranted, they are difficult to carry out, costly, and will not yield data for years. More immediate information regarding endometrial safety may be obtained from studies measuring endometrial tissue and serum concentrations of estradiol, estrone, and relevant equine estrogens after administration of different estrogen formulations and doses. This would allow us to understand better the metabolism of estrogens by the vagina and endometrium, and how much estrogen is reaching the endometrium. Here, we discuss metabolism, receptor binding, and signaling of estrogens in vaginal and endometrial tissue, and summarize the existing studies on the endometrial impact of low-dose vaginal estrogen treatment in postmenopausal women.

Phytoestrogens and Health Effects

Phytoestrogens are literally estrogenic substances of plant origin. Although these substances are useful for plants in many aspects, their estrogenic properties are essentially relevant to their predators. As such, phytoestrogens can be considered to be substances potentially dedicated to plant-predator interaction. Therefore, it is not surprising to note that the word phytoestrogen comes from the early discovery of estrogenic effects in grazing animals and humans. Here, several compounds whose activities have been discovered at nutritional concentrations in animals and humans are examined. The substances analyzed belong to several chemical families, i.e., the flavanones, the coumestans, the resorcylic acid lactones, the isoflavones, and the enterolignans. Following their definition and the evocation of their role in plants, their metabolic transformations and bioavailabilities are discussed. A point is then made regarding their health effects, which can either be beneficial or adverse depending on the subject studied, the sex, the age, and the physiological status. Toxicological information is given based on official data. The effects are first presented in humans. Animal models are evoked when no data are available in humans. The effects are presented with a constant reference to doses and plausible exposure.

Female Reproductive Systems: Hormone Dependence and Receptor Expression

The female reproductive system which consists of the ovaries, uterus (myometrium, endometrium), Fallopian tubes, cervix and vagina is exquisitely sensitive to the actions of steroid hormones. The ovaries play a key role in the synthesis of bioactive steroids (oestrogens, androgens, progestins) that act both within the tissue (intracrine/paracrine) as well as on other reproductive organs following release into the blood stream (endocrine action). Sex steroid receptors encoded by the oestrogen (ESR1, ESR2), progesterone (PR) and androgen (AR) receptor genes, which are members of the superfamily of ligand activated transcription factors are widely expressed within these tissues. These receptors play critical role(s) in regulation of cell proliferation, ovulation, endometrial receptivity, myometrial cell function and inflammatory cell infiltration. Our understanding of their importance has been informed by studies on human tissues and cells, which have employed immunohistochemistry as well as a wide range of molecular and genetic methods to identify which processes are dependent steroid ligand activation. The development of mice with targeted deletions of each of these receptors has provided complementary data that has extended our appreciation of cell-cell interactions in the fine tuning of reproductive tissue function. This large body of work has formed the basis of new and improved therapeutics to treat conditions such as infertility.

Vaginal Aging-What We Know and What We Do Not Know

The aging of the organism is a complex and multifactorial process. It can be viewed in the context of the whole organism, but also of individual tissues and organs. The problem of vaginal aging and the related genitourinary syndrome of menopause significantly reduces the quality of women’s lives. The aging process of the vagina includes estrogen deficiencies, changes in the microbiome, and changes at the genetic level associated with DNA methylation. During the menopause, the number of Lactobacillus colonies decreases, and the number of pathological bacteria colonies increases. The decrease in estrogen levels results in a decrease in vaginal epithelial permeability, perfusion, and elastin levels, resulting in vaginal dryness and atrophy. Changes at the molecular level are the least clear. It can also be assumed that, similarly to the tissues studied so far, there are changes in cytosine methylation and TET (ten-eleven translocation) expression. The interrelationships between DNA methylation, hormonal changes, and the vaginal microbiome have not yet been fully elucidated.

Aloe Vera; A new treatment for atrophic vaginitis, A randomized double-blinded controlled trial

AIM OF THE STUDY

Vaginal atrophy is of the most common problems during menopause with significant psychosocial and medical consequences. Estrogen as an approved therapy for vaginal atrophy can be associated with adverse effects and several contraindications in menopause patients. The aim is to compare the effect of Aloe Vera vaginal cream with commercially available estrogen vaginal cream for management of vaginal atrophy in menopause females.

MATERIALS AND METHODS

This is a double-blinded randomized controlled trial on 60menopause female with complaints of vaginal atrophy symptoms. Subjects were randomly allocated in two groups of 30 patients, named as estrogen and Aloe Vera groups. Vaginal health index (VHI), maturity value (MV), vaginal cytologic smear, transvaginal sonography (TVS) and severity of symptoms related to vaginal atrophy were assessed before and after 6-weeks of vaginal cream administration.

RESULTS

Comparison of MV before and after treatment revealed that superficial cells were significantly increased after administration of both vaginal cream (6.67 VS 54.33 in Aloe Vera group; 4.33 VS 59.67 in estrogen group). In addition, VHI (13.83 vs 20.13 in Aloe Vera group; 13.97 vs 19.93 in estrogen group) and symptoms of vaginal atrophy (3.63 vs 1.10 in Aloe Vera group; 3.90 vs 0.66 in estrogen groups) were also significantly improved after treatment in both groups. There was no significant difference between groups after treatment except for fluid volume with a superiority in Aloe Vera group (P-value = 0.004) CONCLUSION: Aloe Vera vaginal cream can be as effective as estrogen vaginal cream in the management of vaginal atrophy in menopause females.

LAPAROSCOPIC PECTOPEXY. IRM EHPERIENCE

A study carried out at the Institute of Reproductive Medicine proved that laparoscopic pectopexy is a reliable, safe and convenient method for treating pelvic organ prolapse and can be a good alternative to sacrocolpopexy.

Experience with ospemifene in patients with vulvar and vaginal atrophy and urinary incontinence: case studies

Pelvic floor muscle atrophy and collagen loss in connective tissue due to declining estrogen production in women as they age may underlie the increasing prevalence of urge and stress incontinence. Estrogen therapy can correct the deficiency of estrogen receptors in genitourinary structures after menopause, but estrogen is not suitable for all women. A series of retrospective studies showed that urinary symptoms improved in women with overactive bladder syndrome who were receiving ospemifene for vulvovaginal atrophy (VVA), a component of genitourinary syndrome of menopause. Two case studies presented in this article support the findings. The woman in case 1 was 76 years old, had a 4-year history of urinary incontinence (UI), and several risk factors for urinary symptoms. During 15 months' treatment with ospemifene for VVA, her urinary symptoms also improved as evidenced by a reduction (from four/day to one/day) in sanitary pad requirements to manage leakage. The patient in case 2 had predominantly moderate-to-severe VVA and mild mixed UI. During 6 months' treatment with ospemifene, she experienced marked improvement in VVA symptoms, including normalization of vaginal pH and disappearance of dyspareunia, accompanied by a decrease in urinary symptoms, which allowed her to resume a normal exercise program.

Expression of Estrogen-Related Receptors in Localized Provoked Vulvodynia

Eight percent of women suffer from vulvodynia, a chronic pain condition with unknown etiology. Inflammation and dysregulation of estrogen signaling have been suggested to play a role in the pathogenesis of localized provoked vulvodynia (LPV). Therefore, the aim of the study was to analyze protein expression levels of estrogen-related receptors ERRα, ERRß, ERRγ, estrogen receptor (ERα), and progesterone receptor (PRα) and CD3-positive T cells in the vulvar vestibulum obtained from women suffering from LPV in comparison to healthy, unaffected controls. Vulvar vestibulum tissue specimens were obtained from LPV patients (n = 12) who had undergone modified posterior vestibulectomy and from 15 healthy controls. Protein expression of ERRα, ERRß, ERRγ, ERα, and PRα and CD3-positive T cells was analyzed by immunohistochemistry (IHC). Expression of ERRß was significantly more pronounced in samples from LPV compared to healthy controls (p = 0.006). No significant difference in the expression patterns of ERRα, ERRγ, ERα, PRα, or CD3 cells was detected. To our knowledge, this is the first study reporting ERR expression in normal vestibulum and in vestibulectomy samples from LPV patients. The higher level of ERRß expression detected by IHC may reflect dysregulation of estrogen signaling in LPV.

Immunohistochemical evaluation of oestrogen receptors α and β in epithelium of the vaginal mucous membrane in women after oestrogen therapy

Oestrogens act on target cells through α and β receptors (ERα and ERβ). Expression of oestrogen receptors is associated with the age and menopausal condition of women.

The aim of the study was an immunohistochemical evaluation of ERα and ERβ receptors in epithelium of the vaginal mucous membrane of women subjected to different forms of hormonal therapy (HTM).

Oestrogen receptors ERα and ERβ were identified using immunohistochemical methods and evaluated in smears of vaginal mucous membranes collected from 60 patients subjected to HTM (including 20 patients after oral therapy, 20 patients after transdermal therapy, and 20 patients after vaginal therapy). The results showed a significant change in immunoreactivity of both studied receptors after three months of hormone therapy. The biggest differences in the changes of intensity of ERα and ERβ reactions were observed in patients subjected to vaginal therapy. Immunostaining for α receptor showed differences between three types of hormone therapy. The highest increase in the overall intensity occurred after three months of topical therapy. Immunostaining for Erβ also varied for different types of hormone therapy.

The results indicate that hormone therapy administered vaginally is the most effective in the treatment of urogenital ailments during menopause. In addition, topical therapy eliminates adverse effects of systemic oestrogen.

Estrogenic activity of isoflavonoids from the stem bark of the tropical tree Amphimas pterocarpoides, a source of traditional medicines

Various preparations of the African tree Amphimas pterocarpoides Harms are traditionally used to treat endocrine- related adverse health conditions. In the ovariectomized rat, the enriched in phenolics fraction of the methanol extract of stem bark of A. pterocarpoides acted as vaginotrophic agent of considerably weaker uterotrophic activity compared to estradiol. Evaluation of the fraction and 11 isoflavonoids isolated therefrom using Ishikawa cells and estrogen receptor (ER) isotype-specific reporter cells suggested that the estrogenic activity of the fraction could be attributed primarily to daidzein and dihydroglycitein and secondarily to glycitein. The potency-based selectivity of daidzein, dihydroglycitein and glycitein for gene expression through ERβ versus ERα, expressed relative to estradiol, was 37, 27 and 20, respectively. However, the rank order of relative-to-estradiol potencies of induction of alkaline phosphatase in Ishikawa cells, a reliable marker of estrogenic activity, was daidzein>dihydroglycitein>>glycitein. The considerably higher estrogenic activity of dihydroglycitein compared to glycitein could be attributed to the partial agonist/antagonist activity of dihydroglycitein through ERβ. Calculation of theoretical free energies of binding predicted the partial agonism/antagonism of dihydroglycitein through ERβ. The fraction and the isolated isoflavonoids promoted lactogenic differentiation of HC11 mammary epithelial cells at least as effectively as premenopausal levels of estradiol. This data suggests that the estrogenic activity of the fraction likely depends on the metabolism of glycitein to dihydroglycitein; that the fraction could exert vaginotrophic activity likely without challenging endocrine cancer risk more than estrogen-alone supplementation; and that the fraction's safety for the reproductive track warrants a more detailed evaluation.

Reduction in ERRα is associated with lichen sclerosus and vulvar squamous cell carcinoma

OBJECTIVE

ERRs (estrogen-related receptors) regulate energy metabolism, the cell cycle and inflammatory processes in both normal and cancer cells. Chronic inflammation induced by lichen sclerosus (LS) or human papilloma virus (HPV) precedes vulvar squamous cell carcinoma (vulvar SCC). We investigated the expression of ERRα, ERRβ and ERRγ in normal vulvar skin, LS as well as LS-dependent and LS-independent/HPV-related vulvar SCC.

METHODS

A total of 203 samples were analyzed for ERRα, ERRβ and ERRγ by using immunohistochemistry. These included 37 normal vulvar skin samples, 110 LS samples, 6 vulvar intraepithelial neoplasia (VIN) samples and 50 vulvar SCC samples.

RESULTS

A substantial reduction in or disappearance of ERRα was detected in all vulvar SCC samples. A total of 79% of childhood-onset LS and 51% of adulthood-onset LS lesions showed decreases in ERRα staining. A gradual reduction in ERRα cytoplasmic staining was observed from healthy vulvar skin to precursor lesions and further to SCC. Nuclear ERRα staining was observed in 8/33 (24%) LS-dependent and 10/17 (59%) LS-independent SCC samples.

CONCLUSIONS

ERRα, a key regulator of cell energy metabolism, may play a role in the pathogenesis of both LS and vulvar SCC.

Effects of Glycine max (L.) Merr. soy isoflavone vaginal gel on epithelium morphology and estrogen receptor expression in postmenopausal women: a 12-week, randomized, double-blind, placebo-controlled trial

OBJECTIVE

Evaluate the effects of vaginal administration of isoflavones derived from Glycine max (L.) Merr. as a treatment option for vaginal atrophy, on the morphology and expression of estrogen receptors in vaginal epithelium of postmenopausal women.

METHODS

The double-blind, randomized, placebo-controlled, clinical trial. Sixty women were treated for 12 weeks with isoflavone vaginal gel 4% (1g/day) and a placebo gel. After 4 and 12 weeks, the vaginal atrophy symptoms were classified at none, mild, moderate and severe and the vaginal cytology were taken to determine the maturation value. Vaginal pH was measured at the beginning and end of therapy. Microbiopsies in vaginal fornix were performed before the treatment and after 12 weeks of treatment.

RESULTS

Isoflavone vaginal gel was effective for relief of vaginal dryness and dyspareunia symptons and an increase in the intermediate and superficial cells was noted. The vaginal pH in the isoflavone group was 7.1 at baseline and 5.4 after 12 weeks, whereas in the placebo group there was no significant change. A significant increase in thickness after treatment was detected in the Isoflavone Group. The percentage of estrogen receptor positive cells in vaginal epithelium for the Isoflavone Group ranged from 58.5% at the beginning of treatment to 82.6% after 12 weeks. These results were superior to placebo gel.

CONCLUSION

Glycine max (L.) Merr. at 4% vaginal gel on a daily basis in postmenopausal women led to improvements in vaginal atrophy symptoms, maturation values, vaginal pH, morphology and expression of estrogen receptors in vaginal epithelium. Isoflavones proved good treatment options for relief of vulvovaginal atrophy.

Estrogen receptor expression and vessel density in the vagina wall in postmenopausal women with prolapse

After menopause, critically estrogen low levels result in modifications in vaginal wall. This cross-sectional study aims to determine whether there is a change in the number of vessels in the lamina propria of the vagina after menopause in parallel to the ER-alpha expression on the vaginal wall. Twelve women who underwent a genital surgery for genital prolapse up to grade II were selected. They were divided into two groups: a premenopausal group (PG) consisting of six women who were 18-40 years old with FSH levels =12 mIU/ml and regular cycles, and a menopausal group (MG) consisting of six women at least one year after menopause who were <65 years old with FSH levels =40 mIU/ml. Slides were stained for ER-alpha immunohistochemistry, and an endothelial cell marker CD3 was used to label vessels which were identified by using a system for morphometry. The number of vessels was significantly higher in the PG than in the MG both on the anterior wall (PG: 1.055 ± 145.8 vessels/mm(2), MG: 346.6 ± 209.9 vessels/mm(2), p<0.0001) and on the posterior wall (PG: 1064 ± 303.3 vessels/mm(2), MG: 348.6 ± 167.3 vessels/mm(2), p=0.0005). The ER-alpha score was significantly higher in the PG than the score for the MG on both the anterior and posterior walls (PG: 6.0 ± 0.52, MG: 2.5 ± 0.89, p=0.007; PG: 5.8 ± 0.79, MG: 2.7 ± 0.95, p=0.03, respectively). There was a positive correlation between the ER-alpha score and the vessel concentration on the anterior (r=0.6656, p=0.018) and posterior (r=0.6738, p=0.016) vaginal walls. Age was strongly negatively correlated with vessel concentration on the vaginal walls (respectively r=-0.9033, p<0.0001, r=-0.7440, p=0.0055). Therefore, postmenopausal women with genital prolapse have a smaller number of vessels on the vaginal wall compared to normoestrogenic controls with the same pathological condition. Hypoestrogenism and advancing age are factors that are associated to these changes.

Vaginal effects of ospemifene in the ovariectomized rat preclinical model of menopause

Ospemifene is a unique tissue-selective estrogen agonist/antagonist (also known as a selective estrogen receptor modulator [SERM]) with demonstrated efficacy in Phase 3 studies of postmenopausal women with vulvar and vaginal atrophy (VVA). This report describes preclinical studies on the effects of ospemifene in the ovariectomized (OVX) rat model of menopause. Ospemifene (10mg/kg/day) and the SERM comparator, raloxifene (10mg/kg/day) were administered for 2 weeks and both increased vaginal weight; ospemifene was more effective than raloxifene. In addition, ospemifene had a greater effect on increasing vaginal epithelial height compared with raloxifene. The effect on uterine weight was less pronounced for both ospemifene and raloxifene. The ED50 of ospemifene on vaginal epithelial height was 0.39mg/kg/day and the magnitude was nearly the same as was seen with the positive control, 17α-ethinyl estradiol (EE2). In a histological analysis of ospemifene-treated rat vaginas, basal cells were overlaid by 2 to 3 cell layers of thickened goblet-like mucified cells apically; however, the cornification observed with EE2 was absent. Estrogenic activity of ospemifene was confirmed by upregulation of progesterone receptors in vaginal epithelium and stroma. Ospemifene showed similar affinity for estrogen receptor (ER)-α and ER-β, but an overall lower affinity than estradiol. Ospemifene antagonized estrogen response element (ERE)-mediated transactivation on MCF-7 cells, confirming its anti-estrogenic activity in breast cancer cells. The dose response for ospemifene in the rat is consistent with that observed in clinical studies of ospemifene 30 and 60mg, showing that the OVX rat is a highly predictive model of SERM activity in postmenopausal VVA.

Aromatase inhibitors affect vaginal proliferation and steroid hormone receptors

OBJECTIVE

Women with breast cancer who are treated with aromatase inhibitors often experience vaginal atrophy symptoms and sexual dysfunction. This work aims to study proliferation and the presence and distribution of steroid hormone receptors in vaginal biopsies in relation to vaginal atrophy and vaginal pH in women with breast cancer who are on adjuvant endocrine treatment and in healthy postmenopausal women.

METHODS

This is a cross-sectional study that compares postmenopausal aromatase inhibitor-treated women with breast cancer (n = 15) with tamoxifen-treated women with breast cancer (n = 16) and age-matched postmenopausal women without treatment (n = 19) or with vaginal estrogen therapy (n = 16). Immunohistochemistry was used to study proliferation and steroid hormone receptor staining intensity. Data was correlated with estrogen and androgen levels, vaginal atrophy scores, and vaginal pH.

RESULTS

Aromatase inhibitor-treated women had a lower grade of proliferation, weaker progesterone receptor staining, and stronger androgen receptor staining, which correlated with plasma estrone levels, vaginal atrophy scores, and vaginal pH.

CONCLUSIONS

Women with aromatase inhibitor-treated breast cancer exhibit reduced proliferation and altered steroid hormone receptor staining intensity in the vagina, which are related to clinical signs of vaginal atrophy. Although these effects are most probably attributable to estrogen suppression, a possible local inhibition of aromatase cannot be ruled out.

Involvement of estrogen receptor-related receptors in human ovarian endometriosis

OBJECTIVE

To determine whether decreased estrogen receptor alpha (ER-α) expression in endometriotic lesions could be balanced by an increased expression of estrogen receptor-related receptors (ERRs). To evaluate whether ERR-α expression is influenced by hormonal change in fertile and menopausal women.

DESIGN

Prospective controlled study.

SETTING

University Hospital, Department of Gynecology.

PATIENT(S)

Twenty-five women: 20 women of reproductive age with (n = 10) and without (control; n = 10) endometriosis and 5 menopausal women.

INTERVENTION(S)

Real-time polymerase chain reaction (qPCR). Immunohistochemistry.

MAIN OUTCOME MEASURE(S)

The ER and ERR expression levels were studied by reverse transcriptase-qPCR, ELISA, and immunohistochemistry using endometriotic and normal endometrial tissues. The ERR-α protein distribution was performed by immunohistochemistry in fertile and menopausal women.

RESULT(S)

Increased levels of ER-β were associated with ER-α, ERR-α, and ERR-γ reductions in ectopic tissue but not in eutopic and normal endometria. Similar levels of ERR-β were found in women with and without endometriosis. The ERR-α expression was similar in proliferative and secretory endometrial samples, whereas a down-regulation of this receptor was found in atrophic tissue.

CONCLUSION(S)

Our data confirm the up-regulation of ER-β as the principal receptor involved in the progression of human endometriosis. In addition, we found that ERR-α seems to be unresponsive to hormonal changes during the menstrual cycle.