Urogenital effects of selective estrogen receptor modulators: a systematic review

Evaluation of the Pelvic Floor of Women with Breast Cancer Using Tamoxifen by Transperineal 3D Ultrasonography

Objective

This study aimed to investigate the anatomical changes in the pelvic floor of women with breast cancer using tamoxifen by transperineal 3D ultrasonography and their effect on the urinary incontinence and sexual dysfunction.

Methods

Ninety-four patients with breast cancer using TAM in the study group and ninety-five healthy women of the same age in the control group were included in this prospective cohort study. Female Sexual Function Index and Incontinence Questionnaire-Short Form scales were applied to both groups. Ultrasonographic evaluation was performed at resting and Valsalva Maneuver with a convex (3-8 MHz) probe transperineally and the levator urethra gap and levator hiatus diameter were measured after 3-dimensional imaging. Independent t-tests were performed for statistical analysis.

Results

The mean age and body mass index of the experimental group versus control groups were 46.3 ± 6.12 years versus 46.4 ± 5.23 years and 27.6 ± 4.34 kg/m2 versus 29.2 ± 6.45 kg/m2, respectively. LUG and LH values were found significantly higher for the experimental groups compared to control groups at 17.23 ± 2.53 mm versus 14.1 ± 2.23 mm and 21 ± 2.45 cm2 versus 18 ± 4.56 cm2, respectively. (p < 0.05). The FSFI score significantly decreased (12.49 ± 3.58 versus 20.89 ± 3.69) and the ICIQ-SF score increased (4.02 ± 0.34 versus 2.34 ± 0.45) in the experimental group in comparison to control group (p < 0.05).

Conclusion

This study demonstrated that the effects of TAM usage on pelvic floor can be detected by measuring the changes in the levator ani muscle using the transperineal 3D USG. With transperineal USG screening, pelvic floor changes can be early diagnosed and clinical measures can be taken before they become symptomatic.

Prevalence of pelvic floor disorders, associations of endocrine therapy, and surgical intervention among breast cancer survivors

INTRODUCTION AND HYPOTHESIS

To evaluate prevalence of pelvic floor disorders, association of endocrine therapy with pelvic floor disorders, and rates of pelvic floor surgery among breast cancer survivors compared to matched controls without history of cancer.

METHODS

This is a retrospective, cohort study using electronic medical record data from a ten-hospital regional healthcare system. A total of 19,483 women diagnosed with breast cancer between January 2008 and April 2020 were propensity score matched to 19,483 women without a history of cancer. Medical charts were abstracted for ICD-9 and ICD-10 codes for pelvic floor disorders, use of endocrine therapy, and CPT codes for pelvic floor surgeries and procedures.

RESULTS

Overall, the prevalence of pelvic floor disorders was lower among breast cancer survivors (8.8% vs. 22.6%, p < 0.001), and mean time to development of pelvic floor disorders among breast cancer survivors was 3 years. Selective estrogen receptor modulators and aromatase inhibitors were associated with pelvic organ prolapse and stress urinary incontinence, while estrogen antagonists were associated with urge urinary incontinence and lower urinary tract symptoms. Women with breast cancer had similar or higher rates of pelvic floor surgery compared to matched controls.

CONCLUSIONS

Rates of pelvic floor disorders were lower among breast cancer survivors compared to controls but rates of surgical intervention did not differ and were higher for some conditions among breast cancer survivors.

IMPLICATIONS FOR CANCER SURVIVORS

Screening for these disorders should be considered as part of routine survivorship care.

Challenges of Managing Lower Urinary Tract Symptoms in Women with Tamoxifen Use

Objective:

Tamoxifen complicates management of conditions such as urinary tract infections (UTIs), urinary incontinence (UI), and/or pelvic organ prolapse (POP) that traditionally benefit from hormonal intake; thus, we reviewed our experience in managing these hormonally deprived women.

Materials and Methods:

After IRB approval, electronic medical records from women with current use or history of tamoxifen use and referred to a tertiary care center with female pelvic medicine and reconstructive surgery expertise for UTI, UI, and/or POP were reviewed.

Results:

From 2015 to 2020, 32 women treated with tamoxifen 10–40 mg for a median of 4 years were referred for UTIs (9), UI (10), symptomatic POP (8), or for a combination of these (5). Participants with UTI treated with antibiotics, prophylactic supplements, and/or electrofulguration had satisfactory response at median follow-up of 1 year (interquartile range [IQR]: 0.5–1). Ten of 15 women with UI chose intervention, with no self-reported UI recurrence at median follow-up of 2.5 years (IQR: 1–3). All but one participant with POP underwent vaginal or open/robotic mesh repairs, with satisfactory outcomes at median follow-up of 3 years (IQR: 2–7).

Conclusions:

The management of UTIs, UI, and POP in women on tamoxifen or unable to benefit from hormonal intake is challenging, but traditional interventions can be considered with satisfactory results.

Age and/or postmenopausal status as risk factors for pelvic organ prolapse development: systematic review with meta-analysis

INTRODUCTION AND HYPOTHESIS

Age is named as a risk factor for pelvic organ prolapse (POP), despite not being the primary outcome for many observational studies. Postmenopausal status is another associated factor but has many confounders. We aimed to systematically review the role of age and/or postmenopausal status in POP development.

METHODS

Systematic review addressing age and hormones, more specifically by postmenopausal status, from inception to March 2020 in four databases (PubMed, Embase, WOS, Cochrane Library). Quality of evidence was classified by the ROBINS-I classification for non-randomized studies. Experimental studies, animal studies, studies linking age with recurrent POP and case series were excluded. Effect estimates were collected from adjusted odds ratio plus 95% confidence intervals. Significance level was 5%. A discussion exploring mechanistic factors was also included.

RESULTS

Nineteen studies (11 cross sectional, 6 cohort and 2 case control) were included for quantitative analysis. Only two studies presented a low overall risk of bias for age; most of the domains were of moderate risk. Every additional year was responsible for a 10% increase in the risk to develop POP (OR = 1.102 [1.021-1.190]; i² = 80%, random analysis, p = 0.012). This trend was confirmed when age was dichotomized into a cutoff of 35 (p = 0.035) and 50 (p < 0.001) years. Although an increase in the risk for POP was noted in postmenopausal women, this did not reach statistical significance (OR = 2.080 [0.927-4.668], i² = 0%, p = 0.076).

CONCLUSION

Age is a risk factor for POP; postmenopausal status was not statistically associated with POP, prompting the need for further studies addressing this factor.

Long-time qingyan formula extract treatment exerts estrogenic activities on reproductive tissues without side effects in ovariectomized rats and via active ER to ERE-independent gene regulation

The reproductive tissues are negatively influenced by estrogens in hormone therapy. Qingyan formula ethanol extract (QYFE)’s estrogenic effects and safety on reproductive tissues after long-term administration and its mechanism via estrogen receptor (ER) pathway haven’t been studied. Here, we characterized its estrogenic effects using ovariectomized rats together with in vitro studies for further molecular characterization. Ovariectomized rats were treated with QYFE at doses of 0.7, 1.4, and 2.8g/kg for 12 weeks. The results showed QYFE has a potent estrogenic activity, as indicated by restoring the disappeared estrous cycle, antagonizing the atrophy of uterus, vagina and mammary gland, and the estrogen decline in circulation caused by ovariectomy. In addition, QYFE upregulated ERα and ERβ expressions and had a less stimulatory effect on PCNA and ki-67 antigen in reproductive tissues compared with estradiol valerate. QYFE components can bind to ERα and ERβ, significantly increased ERα/β-ERE luciferase reporter gene expression, upregulated the expressions of ERs, PR and pS2 in MCF-7 cells at protein and gene level. All these activities were significantly inhibited by the ER antagonist ICI182,780. QYFE’s estrogenic activity maybe mediated by stimulating biosynthesis of estrogen and increasing the quantity of ERs in target tissue and via active ER to ERE-independent gene regulation.

Postmenopausal hormone therapy is accompanied by elevated risk for uterine prolapse

OBJECTIVE

Receptors for estrogen and progesterone are present in the pelvic floor, and therefore, postmenopausal hormone therapy may affect its function. We compared the former use of estradiol-progestogen postmenopausal hormone therapy in nonhysterectomized women with a uterine prolapse surgery (N = 12,072) and control women (N = 33,704).

METHODS

The women with a history of uterine prolapse operation were identified from the Finnish National Hospital Discharge Register, and the control women from the Finnish Central Population Register. The use of hormone therapy was traced from the national drug reimbursement register, and the odd ratios with 95% CIs for prolapse were calculated by using the conditional logistic regression analysis.

RESULTS

The women with uterine prolapse had used hormone therapy more often than control women (N = 4,127; 34.2% vs N = 9,189; 27.3%; P < 0.005). The use of hormone therapy was accompanied by significant (23%-53%) elevations in the risk for prolapse, being higher with longer exposure. The risk elevations (33%-23%) were comparable between sole norethisteroneacetate-estradiol and sole medroxyprogesteroneacetate-estradiol therapy. The use of estradiol in combination with a levonorgestrel releasing intrauterine device was accompanied by a 52% elevation.

CONCLUSIONS

The postmenopausal use of estradiol in combination with various progestogen regimens may weaken the pelvic floor, resulting in uterine prolapse. This data should be incorporated into the information given to the users of estradiol-progestogen hormone therapy.

Narrative review of the epidemiology, diagnosis and pathophysiology of pelvic organ prolapse

The exact prevalence of pelvic organ prolapse is difficult to establish. The anatomical changes do not always consist with the severity or the symptoms associated with prolapse. There are many risk factors associated with pelvic organ prolapse and this review aims to identify the epidemiology and pathophysiology while looking at the known risk factors for pelvic organ prolapse. PubMed search involved a number of terms including: epidemiology, risk factors, reoccurrence indicators, management and evaluation. Several risk factors have been associated with pelvic organ prolapse, all contribute to weakening of the pelvic floor connective tissue/collagen, allowing the pelvic organs to prolapse through the vaginal walls. Among the risk factors are genetic background, childbirth and mode of delivery, previous hysterectomy, menopausal state and the ratio between Estrogen receptors. The “Integral theory” of Petros and the “Levels of Support” model of Delancey enable us to locate the defect, diagnose and treat pelvic organ prolapse.

The currently available demographic data is not reliable enough to properly estimate the true extent of pelvic organ prolapse in the population. However, standardization of the diagnosis and treatment may significantly improve our ability to estimate the true incidence and prevalence of this condition in the coming years.

Salvia miltiorrhiza bunge increases estrogen level without side effects on reproductive tissues in immature/ovariectomized mice

Salvia miltiorrhiza bunge(SM) is a popular herb for alleviating menopausal symptoms, although the scientific evidence of applying SM to estrogen replacement therapy is limited. In this study, we characterized the estrogenic activity of SM using in vivo models of immature and ovariectomized (OVX) mice and performed in vitro studies focusing on the estrogen receptor (ER) pathway for further molecular characterizations. SM treatments demonstrated significant estrogenic activity by promoting the development of uterus and vagina in immature mice, restoring the estrus cycle and reversing the atrophy of reproductive tissues in OVX mice, as well as increasing the expressions of ERα and ERβ at protein and mRNA level in the reproductive tissues. Meanwhile, SM significantly increased estradiol in serum, and decreased follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in the circulation of immature and OVX mice. SM could stimulate the binding effect of ERα and ERβ, and significantly induce ERα/β-estrogen response element (ERE) luciferase reporter gene expression. All these activities were inhibited by the ER antagonist ICI182, 780. This study demonstrates SM exerts estrogenic effects by stimulating biosynthesis of estrogen and increasing ERs in target tissues without side effects on reproductive tissues and through ER-ERE-dependent pathway.

Endocrine therapy and urogenital outcomes among women with a breast cancer diagnosis

PURPOSE

Endocrine therapy for breast cancer can exacerbate menopausal symptoms. The association between endocrine therapy and common pelvic floor disorders including urinary incontinence has rarely been evaluated. We examined urogenital and sexual side effects among women with a breast cancer diagnosis, comparing endocrine therapy users to nonusers.

METHODS

Urogenital and sexual symptoms were self-reported during the enrollment interview within the University of North Carolina Cancer Survivorship Cohort. Tumor characteristics and endocrine therapy use were collected from medical and prescription records. We calculated multivariable prevalence ratios (PR) and 95 % confidence intervals (CI) for the association of endocrine therapy (versus no endocrine therapy) and urinary incontinence, overall and by therapy type (tamoxifen or aromatase inhibitors). PROMIS Sexual Function and Satisfaction domain scores were compared across endocrine therapy groups.

RESULTS

Among the 548 women with a breast cancer diagnosis, 49 % received endocrine therapy. Overall, 18 % of women reported urinary incontinence symptoms. We observed no association between urinary incontinence and endocrine therapy use overall (PR = 0.97; 95 % CI 0.67, 1.43), tamoxifen (PR = 1.20; 95 % CI 0.74, 1.96), or aromatase inhibitors (PR = 0.89; 95 % CI 0.55, 1.42), compared to no use. Approximately 55 % of women were sexually active. Sexual function scores did not vary according to endocrine therapy use, although urinary incontinence was associated with lower satisfaction scores (p = 0.05).

CONCLUSIONS

Our findings demonstrate a high prevalence of urinary incontinence after breast cancer diagnosis similar to the overall prevalence in older U.S. women, and this did not vary strongly according to use of endocrine therapy.

Evaluation of Ki-67 antigen expression in the vaginal epithelium of castrated female rats treated with raloxifene and tamoxifen: a comparative study

OBJECTIVE

The aim of this study was to evaluate the effects of raloxifene and tamoxifen on Ki-67 antigen expression in the vaginal epithelium of castrated rats.

MATERIAL AND METHODS

Thirty-nine virgin, adult, castrated female Wistar-Hannover rats were randomly divided into three groups: Group I (control, n = 13), Group II (raloxifene, n  = 13) and Group III (tamoxifen, n = 13). After confirmation of their hypoestrogenic state, the rats were given 0.5 ml of propylene glycol (vehicle), 750 μg of raloxifene or 250 μg of tamoxifen, respectively, by gavage, for 30 days. On the 31st day, the rats were euthanized and their vaginas removed and fixed in 10% buffered formalin for of Ki-67 immunohistochemical evaluation. Data were analyzed using Levene's test and Tukey's method (p < 0.05).

RESULTS

Mean Ki-67 expression in groups I, II and III was 27 ± 2.6, 32.3 ± 1.9 and 43.7 ± 3.5, respectively. In Group III (tamoxifen), there was a greater proportion of stained cells compared to Groups I and II (p < 0.0003), with no statistically significant difference between Groups I and II (p = 0.3626).

CONCLUSIONS

The present results show that tamoxifen significantly increased cell proliferation in the vaginal epithelium of the castrated rats and no difference between the raloxifene and control groups.

Effects of ospemifene on the female reproductive and urinary tracts: translation from preclinical models into clinical evidence

Objective

Treatment of menopausal symptoms by compounds with tissue-selective estrogen agonist/antagonist effects, often called selective estrogen receptor modulators, has been researched as an alternative to the use of estrogen therapy. These structurally diverse molecules elicit tissue-dependent responses in hormone-responsive tissues and organs, exhibiting variations in estrogenic activity in preclinical models of postmenopausal reproductive tissues that may improve postmenopausal women’s health (eg, prevention and treatment of breast cancer, osteoporosis, and vulvar and vaginal atrophy).

Methods

This literature review investigates whether preclinical data predicted the clinical effects of ospemifene on female reproductive and urinary tract tissues and compares these findings with the specific vaginal effects of other estrogen receptor agonists/antagonists (tamoxifen, raloxifene, and bazedoxifene) in preclinical and clinical studies. Lasofoxifene, although not currently available, is included because of its unique effects on vaginal tissue.

Results

The response of endometrial and vaginal tissues to estrogen receptor agonists/antagonists can be differentiated using transvaginal ultrasound, endometrial histopathology, cytologic examination of vaginal smears, assessment of physical changes in the vagina, and relief of symptoms associated with vulvar and vaginal atrophy (such as dyspareunia).

Conclusions

Available evidence indicates that ospemifene has unique effects on tissue, leading to a favorable long-term profile for the relief of vulvar and vaginal atrophy compared with other estrogen receptor agonists/antagonists (eg, tamoxifen, raloxifene, and bazedoxifene) with no short-term concerns about endometrial safety (based on endometrial hyperplasia, carcinoma, endometrial spotting, and endometrial bleeding).

Short-time QiBaoMeiRan Formula Treatment Exerts Estrogenic Activities without Side Effects on Reproductive Tissues in Immature Mice

The Chinese herbal preparation QiBaoMeiRan formula (QBMR) displayed estrogenic effects in ovariectomized rats after long-term administration in a previous study. The uterus and vagina are negatively influenced by estrogens in hormone therapy. While QBMR is known to be a phytoestrogen, its estrogenic effects and safety on reproductive tissues after short-term administration and its mechanism via estrogen receptor (ER) pathway haven’t been studied. Here, we characterized its estrogenic effects using immature mice together with in vitro studies for further molecular characterization. Immature mice were treated with QBMR at doses of 1.125, 2.25, and 4.5 g/kg for 7 days. 1.125 and 2.25 g/kg QBMR promoted the growth and development of uterus and vagina, and upregulated ERα and ERβ expression in reproductive tissues. QBMR had a stimulatory effect on proliferating cell nuclear antigen in vagina but not in uterus, and was without any influence on ki-67 antigen in uterus and vagina. QBMR significantly induced luciferase expression from the ERα/β-estrogen response element (ERE) luciferase reporter and upregulated ERα and ERβ expressions in MCF-7 cells, which were significantly inhibited by estrogen antagonist ICI182,780. This study demonstrated QBMR exerts estrogenic effects on reproductive tissues without side effects and through ER-ERE-dependent pathway.

In vivo estrogenic-like activities of Gouania longipetala Hemsl. (Rhamnaceae) bark extracts in a post-menopause-like model of ovariectomized Wistar rats

ETHNOPHARMACOLOGICAL RELEVANCE

Gouania longipetala is commonly used in Cameroonian traditional medicine to manage women fertility and menopausal complaints. However, despite this use, the estrogenic properties of G. longipetala have not been studied until now.

AIM OF STUDY

The present study was aimed to assess estrogenic activities of the stem bark aqueous (GLA) and ethanolic (GLE) extracts of G. longipetala in post-menopause-like model of ovariectomized (Ovx) Wistar rats.

MATERIAL AND METHODS

Animals were either sham-operated or Ovx. 84 days after ovariectomy, animals were divided into seven groups of five animals and were daily treated for 28 days with distilled water (10 mL/kg) for group 1, 2% solution of Tween 80 (10 mL/kg) for group 2, estradiol valerate (1 mg/kg) for group 3, GLA (45 or 180 mg/kg) and GLE (40 or 160 mg/kg) for groups 4 to 7 respectively. Sham-operated animals daily received distilled water (10 mL/kg). During the experimental period, the body weight was registered every week. At the day 29, blood pressure was registered by invasive method while uterine and vagina morphometry as well as body, uterine and abdominal fat weights changes were analyzed. Serum levels of total cholesterol, triglycerides, HDL-cholesterol and LDL-cholesterol were determined. Moreover, oxidative stress markers such as nitrites, reduced glutathione (GSH) and malondialdehyde (MDA) were measured in homogenized liver and aorta.

RESULTS

Compared with the sham control, vagina and uterine dystrophy and elevated blood pressure were observed in Ovx rats treated with vehicles. Biochemical parameters showed a significant increase of total cholesterol, triglycerides, LDL-cholesterol and MDA as well as a significant decrease of nitrites and GSH in Ovx animals treated with vehicle as compared to sham group. GLA and GLE displayed estrogen-like effects on vagina and did not affect uterine wet weight and epithelial height compared with vehicle groups. Both extracts displayed anti-atherogenic properties by reducing AI, AIP and LDL-cholesterol level as compared to vehicles groups. GLA and GLE significantly prevented the increase of MDA induced by ovariectomy as compared to rats treated with vehicles.

CONCLUSION

This study showed that GLA and GLE exhibited estrogenic effects by providing vaginal lubrication, by modulating blood pressure and improving lipid profile, oxidative status and endothelial function and may not have an undesirable influence on the endometrium in ovariectomized rats.

Ospemifene: a first-in-class, non-hormonal selective estrogen receptor modulator approved for the treatment of dyspareunia associated with vulvar and vaginal atrophy

Ospemifene is a selective estrogen receptor modulator (SERM) approved for the treatment of dyspareunia associated with vulvar and vaginal atrophy (VVA) due to menopause. As the first non-hormonal treatment for this indication, the approval of ospemifene represents a significant milestone in postmenopausal women's health. Ospemifene is a triphenylethylene similar in chemical structure to tamoxifen and toremifene. Consistent with other SERMs such as tamoxifen, toremifene, and raloxifene, ospemifene possesses a distinctive mix of estrogenic and antiestrogenic tissue-specific effects in bone, breast tissue, serum lipids, and the vagina. Among the approved SERMs, ospemifene is the only agent with a nearly full estrogen agonist effect on the vaginal epithelium while having neutral to slight estrogenic effects in the endometrium, making ospemifene uniquely suited for the treatment of dyspareunia associated with VVA, also known as atrophic vaginitis, which affects up to 50% of postmenopausal women. This review begins with a brief history of the discovery of ospemifene, its mechanism of action, and its preclinical development, with an emphasis on its tissue-specific effects on bone, breast, uterus and endometrium, serum lipids and vagina. A brief discussion on the genotoxicity of ospemifene compared to tamoxifen and toremifene is included. The focus then shifts to the clinical development of ospemifene from Phase I through Phase III. We will close with the FDA approval of ospemifene and a justification of the future clinical evaluation of ospemifene as a potential breast cancer chemopreventive agent, where several preclinical studies in different rodent breast cancer models strongly suggest ospemifene is as effective as tamoxifen.

An overview of current and emerging SERMs

Selective estrogen receptor modulators (SERMs) are compounds that exhibit tissue-specific estrogen receptor (ER) agonist or antagonist activity, and are used for various indications, including treatment of breast cancer, osteoporosis, and menopausal symptoms. Endometrial safety has been a key differentiator between SERMs in clinical practice. For example, tamoxifen exhibits ER agonist activity in the uterus, resulting in an increased risk of endometrial hyperplasia and malignancy, whereas raloxifene and bazedoxifene have neutral effects on the uterus. Based on their efficacy and long-term safety, SERMs are increasingly being prescribed for women who cannot tolerate other treatment options and for younger women at an increased risk of fracture who may remain on therapy for long periods of time. Continuing advances in the understanding of SERM mechanisms of action and structural interactions with the ER may lead to the development of new agents and combinations of agents to provide optimal treatments to meet the varying needs of postmenopausal women. One such example is the tissue selective estrogen complex, which partners a SERM with 1 or more estrogens, with the aim of blending the desired estrogen-receptor agonist activities of estrogens on vasomotor symptoms, vulvar-vaginal atrophy, and loss of bone mass with the tissue selectivity of a SERM.

Selective estrogen receptor modulators: tissue specificity and clinical utility

Selective estrogen receptor modulators (SERMs) are a diverse group of nonsteroidal compounds that function as agonists or antagonists for estrogen receptors (ERs) in a target gene-specific and tissue-specific fashion. SERM specificity involves tissue-specific expression of ER subtypes, differential expression of co-regulatory proteins in various tissues, and varying ER conformational changes induced by ligand binding. To date, the major clinical applications of SERMs are their use in the prevention and treatment of breast cancer, the prevention of osteoporosis, and the maintenance of beneficial serum lipid profiles in postmenopausal women. However, SERMs have also been found to promote adverse effects, including thromboembolic events and, in some cases, carcinogenesis, that have proven to be obstacles in their clinical utility. In this review, we discuss the mechanisms of SERM tissue specificity and highlight the therapeutic application of well-known and emergent SERMs.

Pharmacological approach to overactive bladder and urge urinary incontinence in women: an overview

Besides life-style changes, electrical stimulation or surgery, pharmacological treatment is becoming the first-choice approach in women suffering from lower urinary tract symptoms (LUTS), including urge urinary incontinence (UUI) and overactive bladder (OAB). Several drugs for the treatment of bladder storage and voiding disorders are currently available and, in the near future, novel compounds with higher specificity for the lower urinary tract receptors will be accessible. This will bring optimization of therapy, reducing side effects and increasing compliance, especially in patients with comorbidities and in women. The purpose of this paper is to give an overview on the pharmacotherapy of two common inter-correlated urological conditions, UUI and OAB. The study was conducted by analyzing and comparing the data of the recent international literature on this topic. Advances in the discovery of pharmacological options have dramatically improved the quality of life of patients affected by incontinence, but further studies are needed to increase the effectiveness and safety of the therapies used in this field.

Long-term safety of ospemifene (52-week extension) in the treatment of vulvar and vaginal atrophy in hysterectomized postmenopausal women

OBJECTIVE

To examine the long-term safety of oral ospemifene, a non-estrogen tissue-selective estrogen agonist/antagonist, for the treatment of moderate to severe dyspareunia, a symptom of vulvar and vaginal atrophy (VVA) due to menopause.

STUDY DESIGN

This multicenter, long-term, open-label, safety extension study was conducted in women without a uterus aged 40-80 years (N=301) who received oral ospemifene 60 mg/day for 52 weeks. Participants either continued their 60-mg/day ospemifene dose from the initial 12-week pivotal efficacy study or switched from blinded placebo or ospemifene 30 mg/day to open-label ospemifene 60 mg/day. The 52-week open-label extension period plus initial 12-week treatment period totaled up to 64 weeks of ospemifene exposure. A 4-week posttreatment follow-up ensued (68 weeks total).

MAIN OUTCOME MEASURES

Safety assessments included adverse events, laboratory studies, physical and gynecologic examination, vital signs, breast palpation, and mammography.

RESULTS

Most treatment-emergent adverse events (TEAEs) during the extension study were mild or moderate in severity. The most common TEAE related to study drug was hot flushes (10%; leading to discontinuation for 2% of patients). One serious TEAE, a non-ST-elevation myocardial infarction in a patient with pre-existing cardiac disease, was considered possibly related to study medication. One mild breast-related TEAE, considered unrelated to study drug, was ongoing at study completion. There were no instances of pelvic organ prolapse, incontinence, venous thromboembolism, fractures, breast cancers or death. No clinically significant adverse changes were observed in other safety parameters.

CONCLUSIONS

Ospemifene is clinically safe and generally well tolerated in postmenopausal patients with dyspareunia, a symptom of VVA.

Effect of tamoxifen on extracellular signal-regulated kinases in the urethra of castrated female rats

OBJECTIVE

The aim was to evaluate the effects of tamoxifen in activating extracellular signal-regulated kinases (ERKs) 1 and 2 in the urethras of castrated female rats.

STUDY DESIGN

Twelve castrated adult female rats were divided into a control group (n=6) in which the animals received vehicle, and the experimental group (n=6) in which the rats received tamoxifen 250 μg/day by gavage for 28 days. Then, the animals were sacrificed and their urethras removed. Proteins were extracted, quantified and processed by Western blot analysis with specific phospho-ERK1 and 2 antibodies. Data were analyzed using Student's t-test (p<0.05).

RESULTS

A significant increase occurred in phospho-ERK1 levels in the experimental group compared to the control group (p<0.01), while no difference was found in phospho-ERK2 levels between the groups (p=0.313).

CONCLUSION

The present results indicate that, at the doses and during the time of treatment used, tamoxifen significantly increased phospho-ERK1 levels in the urethras of castrated female rats.

Gynecologic effects of arzoxifene in postmenopausal women with osteoporosis or low bone mass

OBJECTIVE

The aim of this study was to report the gynecologic safety findings from the Generations trial, a phase 3 study of the selective estrogen receptor modulator (SERM), arzoxifene.

METHODS

A predefined objective of the trial was to evaluate the effects of arzoxifene on the genital tract. Gynecologic examinations were performed yearly, and further gynecologic assessment, including endometrial biopsy, was performed in a predefined subset of women and in those who developed vaginal bleeding.

RESULTS

Overall, 9,354 women were randomized (4,678 to placebo, 4,676 to arzoxifene 20 mg/d). There were 13 adjudicated cases of endometrial cancer (placebo, 4 cases; arzoxifene, 9 cases: P = 0.165) and 6 cases of endometrial hyperplasia (placebo, 2 cases; arzoxifene, 4 cases). Endometrial thickness, assessed at 24- and 36-month transvaginal ultrasounds in a subset of women, increased slightly in women assigned to arzoxifene compared with baseline and women in placebo. At the last measurement, 3 (1.7%) women assigned to placebo and 21 (10.2%) assigned to arzoxifene had an endometrial thickness greater than 5 mm (P < 0.001 for difference between treatment groups). Endometrial polyps were more common in women treated with arzoxifene (n = 37) than in women treated with placebo (n = 18; P < 0.05). Vulvular and vaginal inflammation, including mycotic infections, and vaginal discharge were reported more frequently in women treated with arzoxifene than in women treated with placebo, as were urinary tract infections.

CONCLUSIONS

Gynecologic events were generally more common in women treated with arzoxifene than in women treated with placebo. The gynecologic effects of arzoxifene seem to differ from those of raloxifene, although both SERMs have a benzothiophene structure. Although all SERMs influence cells through the estrogen receptor, they need to be evaluated independently in terms of their effects on various tissues, including the genital tract.

SERMs and SERMs with estrogen for postmenopausal osteoporosis

Bone loss with aging places postmenopausal women at a higher risk for osteoporosis and its consequences such as fractures, pain, disability, and increased morbidity and mortality. Approximately 200 million patients worldwide are affected. The Third National Health and Nutrition Examination Survey (NHANES III) estimated that up to 18% of US women aged 50 and older have osteoporosis and up to 50% have osteopenia. Greater than 2 million osteoporotic related fractures occurred in the United States with direct healthcare costs exceeding $17 billion. Hormone Replacement Therapy (HRT) was a popular option for postmenopausal women before the Women's Health Initiative (WHI). Several agents are available in the U.S., including bisphosphonates, hormone therapy, calcitonin, parathyroid hormone and the selective estrogen receptor modulator (SERM) raloxifene. There are concerns about long term safety and compliance. Therefore, other agents are under investigation. SERMs are a diverse group of agents that bind to the estrogen receptor and each SERM appears to have a unique set of clinical responses, which are not always consistent with the typical responses seen with other SERMs. This article will discuss the SERMs approved in the United States, tamoxifene and raloxifene, and investigational SERMs. The ideal SERM would include the beneficial effects of estrogen in bone, heart and the central nervous system, with neutral or antagonistic effects in tissues where estrogen effects are undesirable(breast and endometrium). A new target in treating postmenopausal osteoporosis is the tissue estrogen complex or the pairing of a SERM with a conjugated estrogen known as a tissue selective estrogen complex (TSEC). This novel approach is currently being evaluated with bazodoxifene which could yield the beneficial effects of estrogens and SERMS, while potentially being more tolerable and safer than either therapy alone.

Sexual steroids in urogynecology

The decline in sex hormone levels that accompanies the menopause has substantial effects on the tissues of the urogenital system, leading to atrophic changes. These changes can have negative effects on sexual and urinary function. The authors evaluate the repercussion of hypoestrogenism and sexual steroids on some elements of the pelvic floor and lower urinary tract. They summarize their research work and review significant published papers. They emphasize the changes in urinary mucosae, periurethral vessels, muscular layer, connective tissue, gene expression, autonomic nervous system receptors, as well as the main clinical aspects involved.

Endometrial safety: a key hurdle for selective estrogen receptor modulators in development

Selective estrogen receptor modulators (SERMs) have the ability to provide mixed functional estrogen receptor (ER) agonist or antagonist activity, depending on the target tissue. Tamoxifen, the first SERM available for clinical use, is regarded as a highly effective agent for the prevention and treatment of breast cancer. However, tamoxifen exhibits ER agonist activity in the uterus and is associated with an increased risk of endometrial hyperplasia and malignancy. Endometrial safety has been an important consideration in the clinical development of SERMs, with improved benefit-risk profiles. Raloxifene, which is currently approved for the prevention and treatment of postmenopausal osteoporosis and for the prevention of breast cancer, seems to have neutral effects on the uterus. Promising results have been observed with the targeted development of newer and more tissue-specific SERMs, many of which are under investigation for postmenopausal osteoporosis. Of the newer SERMs in development, lasofoxifene has been shown to reduce fracture risk and decrease the incidence of breast cancer but has been associated with an increased incidence of vaginal bleeding, endometrial thickening, and endometrial polyps. Lasofoxifene and ospemifene have shown beneficial effects on the vaginal epithelium. Phase 3 clinical data have shown that bazedoxifene is effective in preventing and treating postmenopausal osteoporosis, without adverse effects on the endometrium or breast. Arzoxifene has been evaluated in phase 3 trials for postmenopausal osteoporosis and has been studied for the treatment of uterine malignancies but is no longer in clinical development. Further investigation of newer SERMs is warranted to more clearly define the endometrial safety of these agents.

Effect of hormone replacement and selective estrogen receptor modulators (SERMs) on the biomechanics and biochemistry of pelvic support ligaments in the cynomolgus monkey (Macaca fascicularis)

OBJECTIVE

To evaluate the effect of selective estrogen receptor modulators and ethinyl estradiol on the biomechanical and biochemical properties of the uterosacral and round ligaments in the monkey model of menopause.

STUDY DESIGN

A randomized, double-blind, placebo-controlled study on 11 female macaque monkeys. Ovariectomized monkeys received 12 weeks of placebo, raloxifene, tamoxifen, or ethinyl estradiol. Biomechanical step-strain testing and real-time polymerase chain reaction was performed on the uterosacral and round ligaments.

RESULTS

Tamoxifen and raloxifene uterosacrals expressed differing collagen I/III receptor density ratios, but both selective estrogen receptor modulators showed decreased tensile stiffness compared to ethinyl estradiol and controls.

CONCLUSION

These findings support a possible effect of selective estrogen receptor modulators on biomechanical and biochemical properties of uterosacrals. This may play a role in pelvic organ prolapse.

Bazedoxifene, a selective estrogen receptor modulator: effects on the endometrium, ovaries, and breast from a randomized controlled trial in osteoporotic postmenopausal women

OBJECTIVE

The aim of this study was to evaluate the endometrial, ovarian, and breast safety of bazedoxifene used as a treatment for postmenopausal osteoporosis.

METHODS

Healthy women (aged 55-85 y) with osteoporosis were enrolled in a randomized, double-blind, placebo-controlled phase 3 trial. Participants were randomized to treatment with bazedoxifene 20 or 40 mg, raloxifene 60 mg, or placebo daily for 3 years. Endometrial and ovarian safety was assessed by periodic transvaginal ultrasonography and endometrial biopsy through 24 months. Gynecologic and breast-related adverse events were recorded throughout the study.

RESULTS

Among 753 participants with available transvaginal ultrasonography data, there were no significant between-group differences in overall endometrial thickness or in the percentage of participants with endometrial thickness greater than 5 mm at 12 or 24 months. Changes in the mean endometrial thickness (+/-SE) from baseline were -0.07 +/- 0.11 mm (bazedoxifene 20 mg), 0.10 +/- 0.11 mm (bazedoxifene 40 mg), 0.16 +/- 0.12 mm (raloxifene 60 mg), and -0.08 +/- 0.11 mm (placebo) at 24 months. There was one report of endometrial hyperplasia in each group, and there were zero, two, two, and three reports of endometrial carcinoma with bazedoxifene 20 and 40 mg, raloxifene 60 mg, and placebo, respectively. There were no clinically important changes from baseline in the number or size of ovarian cysts among groups. There was a significantly lower incidence of fibrocystic breast disease (P <or= 0.05) with bazedoxifene compared with raloxifene 60 mg.

CONCLUSION

Bazedoxifene was associated with a favorable endometrial, ovarian, and breast safety profile in postmenopausal women with osteoporosis.

Pharmacology and clinical applications of selective estrogen receptor modulators

Compounds that can be described as selective estrogen receptor modulators (SERMs) have expanded dramatically over the past two decades. The ability of SERMs to act as estrogens in certain tissues while remaining inert or acting as an anti-estrogen in other tissues has opened up opportunities for treating specific estrogen-modulated diseases without accepting the risk of systemic estrogen activity. SERM development has resulted in significant therapeutic advances for breast cancer, osteoporosis and potentially other diseases associated with the menopause. After the publication of the Women's Health Initiative, interest in compound selectivity that reduces menopausal symptoms while protecting bone, breast, uterus and the heart has increased. Future SERMs may also have a therapeutic profile that can be tailored to specific patient populations, including men. This review paper summarizes the characteristics of different SERMs from various pharmacological categories and the feasibility and scope of their use for a large range of disease/health conditions.

Vascular endothelial growth factor expression in the urethral epithelium of castrated adult female rats treated with tamoxifen

OBJECTIVE

The aim of this study was to evaluate the effects of tamoxifen on vascular endothelial growth factor (VEGF) expression in the urethral epithelium of castrated rats.

MATERIALS AND METHODS

Thirty-six adult, castrated, female Wistar-Hannover rats were randomly divided into two groups: group I (n = 16, control), receiving only propylene glycol, and group II (n = 20, tamoxifen), treated with 250 microg/day of tamoxifen for 30 consecutive days by gavage. On the 31st day, the animals were sacrificed and the urethras were immediately removed, separated into the proximal and distal segments and processed for VEGF immunohistochemistry. The data were analysed using Student's t-test (p < 0.05).

RESULTS

The mean percentage of VEGF expression in the epithelium of the proximal urethra of the animals in groups I and II was 64.47+/-3.70 and 74.69+/-3.03, respectively (p < 0.03), whereas the mean percentage of VEGF expression in the distal urethral epithelium of the animals in groups I and II was 53.49+/-4.64 and 68.57+/-3.67, respectively (p < 0.01).

CONCLUSIONS

Our results indicate that, at the dose and during the time of treatment used, tamoxifen increased VEGF expression in the urethral epithelium of castrated rats.

Pelvic organ prolapse and relationship with skeletal integrity

Health burden related to osteoporotic fractures in an aging female population far exceeds that imposed by other chronic disorders such as cardiovascular disease and breast cancer. Bone mineral density assessment and clinical risk factors provide independent insights into fracture risk in individuals. A finite list of clinical risk factors are identified as prognostic of fracture risk, namely among aging women, including low body mass, compromised reproductive physiology (e.g., prolonged periods of amenorrhea and early menopause), parental and personal histories of fracture, and alcohol and tobacco use. Pelvic organ prolapse is a common gynecologic entity and a contributor to age-related morbidities. The purpose of this review is to communicate data identifying pelvic organ prolapse as another clinical risk factor for fracture risk in postmenopausal women and to increase the caregiver's vigilance in anticipating and instituting preventive care strategies to a population (i.e., postmenopausal women with clinically appreciable pelvic organ prolapse) that may be at an enhanced lifetime risk for skeletal fractures.

Estrogen and urinary incontinence

Hormone therapy (HT) has been one of the most commonly used methods to treat postmenopausal disorders including lower urinary tract symptoms such as urinary incontinence (UI). Although it has been suggested that HT improves urinary tract symptoms, little evidence has so far been presented to support this. Recently however, large randomized clinical trials have shown the adverse effects of estrogen on UI and indicate that HT should not be used for prevention or relief of UI in postmenopausal women. Here we review the effects of HT on UI in the light of these clinical trials.

Effects of raloxifene on the urethra of adult castrated female rats

OBJECTIVE

The objective of this study was to evaluate the effects of raloxifene on the weight and epithelial thickness of the urethra of castrated female rats.

METHODS

Forty castrated female rats were randomly separated into two groups: group I (control, n = 20) received only the vehicle, and group II (raloxifene, n = 20) received 750 microg/day of raloxifene for 30 days. On the 31st day, the animals were sacrificed and the urethras were removed for the study. A model for categorical data using the weighted minimum mean square error method and Student's t test were used for the data analysis (p < 0.05).

RESULTS

The mean weights of the urethras in groups I and II were 22 +/- 1.6 mg and 24 +/- 1.7 mg, respectively (p = 0.371). There was an increase in the mean epithelial thickness of the distal segments in group II compared to group I (50.7 +/- 1.9 microm vs. 45.3 +/- 1.6 microm, respectively) (p < 0.04). No statistically significant difference was found in the mean epithelial thickness of the proximal urethra between the two groups (p = 0.187).

CONCLUSION

Raloxifene administered to castrated female rats for 30 days increased the distal urethral epithelial thickness and did not alter the weight of the urethra.

The potential of hormones and selective oestrogen receptor modulators in preventing voiding dysfunction in rats

OBJECTIVE

To investigate whether oestrogen, selective oestrogen receptor modulators (SERMs), and growth hormone (GH) can prevent the development of voiding dysfunction in a postpartum postmenopausal rat model of voiding dysfunction.

MATERIALS AND METHODS

Immediately after spontaneous delivery, nine primiparous Sprague-Dawley rats served as uninjured controls (sham group) and 54 underwent intravaginal balloon dilation. On day 7, the 54 subject rats underwent bilateral ovariectomy. A week later, six treatment groups of nine rats were randomized to receive: normal saline (injured control group), 17beta-oestradiol (E(2)), raloxifene, levormeloxifene, GH, or GH + E(2). The treatment groups received daily subcutaneous injections for 3 weeks. The effects of hormone treatment were examined by conscious cystometry at the end of the study. Voiding dysfunction was defined to include overactive bladder and sphincter deficiency.

RESULTS

The sham rats had a mean (sd) voiding frequency of 3 (0.87) times in 10 min and a bladder capacity of 0.43 (0.13) mL with smooth cystometry curves. The number of rats in each treatment group (each group contained nine rats) that had voiding dysfunction was as follows: E(2), three; raloxifene, six; levormeloxifene, four; and controls, four (P > 0.05 among the groups). Only one rat in the GH-treated group and no rats in the GH + E(2)-treated group had voiding dysfunction, which was significantly less in the GH + E(2)-treated group than in the controls (P = 0.041).

CONCLUSION

This functional data suggest that the development of voiding dysfunction can be prevented by short-term administration of GH and GH + E(2) in our rat model. SERMs and E(2) alone seem to have no therapeutic effect.

Selective estrogen receptor modulators: an update on recent clinical findings

Recent clinical data on selective estrogen receptor modulators (SERMs) have provided the basis for reassessment of the SERM concept. The molecular basis of SERM activity involves binding of the ligand SERM to the estrogen receptor (ER), causing conformational changes which facilitate interactions with coactivator or corepressor proteins, and subsequently initiate or suppress transcription of target genes. SERM activity is intrinsic to each ER ligand, which accomplishes its unique profile by specific interactions in the target cell, leading to tissue selective actions. We discuss the estrogenic and anti-estrogenic effects of early SERMs, such as clomiphene citrate, used for treatment of ovulation induction, and the triphenylethylene, tamoxifen, which has ER antagonist activity in the breast, and is used for prevention and treatment of ER-positive breast cancer. Since the development of tamoxifen, other triphenylethylene SERMs have been studied for breast cancer prevention, including droloxifene, idoxifene, toremifene, and ospemifene. Other SERMs have entered clinical development more recently, including benzothiophenes (raloxifene and arzoxifene), benzopyrans (ormeloxifene, levormeloxifene, and EM-800), lasofoxifene, pipendoxifene, bazedoxifene, HMR-3339, and fulvestrant, an anti-estrogen which is approved for breast cancer treatment. SERMs have effects on tissues containing ER, such as the breast, bone, uterine and genitourinary tissues, and brain, and on markers of cardiovascular risk. Current evidence indicates that each SERM has a unique array of clinical activities. Differences in the patterns of action of SERMs suggest that each clinical end point must be evaluated individually, and conclusions about any particular SERM can only be established through appropriate clinical trials.

Morphometric analysis of the urethra of castrated female rats treated with tamoxifen

OBJECTIVES

The aim of this study was to evaluate the effects of tamoxifen on the weight and thickness of the urethral epithelium of castrated female rats.

METHODS

Forty castrated adult female Wistar-Hannover rats were randomly divided into two groups: Group I (n=20) in which the animals received only the vehicle (propylene glycol) and Group II (n=20) in which the rats received tamoxifen 250microg/day by gavage. After 30 days of treatment, all animals were sacrificed and the urethra was immediately removed for weighing. Next, the urethra was divided into the proximal and distal segments, which were fixed in 10% formaldehyde and submitted to routine histological techniques for morphometric study. The data were analyzed using the weighted minimum mean-square error method and Student's t-test for two independent samples (p<0.05).

RESULTS

There was a significant increase in the mean weight of the urethra in the rats of Group II compared to the control group, 32.0+/-2.0mg and 22.0+/-1.6mg, respectively (p<0.001). The mean thickness of the distal urethral epithelium of the animals treated with tamoxifen was significantly greater than that of the control group, 42.8+/-2.0microm and 36.6+/-1.5microm, respectively (p<0.001). There was no statistically significant difference between the two groups with respect to the epithelial thickness of the proximal urethra (p=0.514).

CONCLUSION

Treating castrated adult rats with 250microg/day of tamoxifen for 30 days may increase the weight of the urethra and the thickness of the distal urethral epithelium.

Estradiol increases urethral tone through the local inhibition of neuronal nitric oxide synthase expression

Estrogens are known to modulate lower urinary tract (LUT) trophicity and neuronal nitric oxide synthase (nNOS) expression in several organs. The aim of this study was to explore the effects of endogenous and supraestrus levels of 17β-estradiol (E2) on LUT and urethral nNOS expression and function. LUT function and histology and urethral nNOS expression were studied in adult female mice subjected either to sham surgery, surgical castration, or castration plus chronic E2 supplementation (80 μg·kg−1·day−1, i.e., pregnancy level). The micturition pattern was profoundly altered by long-term supraestrus levels of E2 with decreased frequency paralleled by increased residual volumes higher than those of ovariectomized mice. Urethral resistance was increased twofold in E2-treated mice, with no structural changes in urethra, supporting a pure tonic mechanism. Acute nNOS inhibition by 7-nitroindazole decreased frequency and increased residual volumes in ovariectomized mice but had no additive effect on the micturition pattern of long-term supraestrus mice, showing that long-term supraestrus E2 levels and acute inhibition of nNOS activity had similar functional effects. Finally, E2 decreased urethral nNOS expression in ovariectomized mice. Long-term supraestrus levels of E2 increased urethral tone through inhibition of nNOS expression, whereas physiological levels of E2 had no effect.

Effects of chronic genistein treatment in mammary gland, uterus, and vagina

BACKGROUND

The isoflavone genistein (GEN) is found in soy (Glycine max) and red clover (Trifolium pratense). The estrogenic activity of GEN is known, and it is widely advertised as a phytoestrogen useful in alleviating climacteric complaints and other postmenopausal disorders. Knowledge of effects of long-term administration of GEN in laboratory animals is scarce, and effects in the uterus and mammary gland after long-term administration have not been studied. The uterus and mammary gland are known to be negatively influenced by estrogens used in hormone therapy.

OBJECTIVES

We administered two doses of GEN [mean daily uptake 5.4 (low) or 54 mg/kg (high) body weight (bw)] orally over a period of 3 months to ovariectomized (ovx) rats and compared the effects with a treatment with two doses of 17beta-estradiol [E(2); 0.17 (low) or 0.7 mg/kg bw (high)]. Mammary glands, vaginae, and uteri were investigated morphologically and immunohistochemically. We quantified the expression of proliferating cell nuclear antigen (PCNA) and progesterone receptor (PR) in the mammary gland.

RESULTS

In rats treated with either of the E(2) doses or the high GEN dose, we found increased uterine weight, and histologic analysis showed estrogen-induced features in the uteri. In vaginae, either E(2) dose or GEN high induced hyperplastic epithelium compared with the atrophic controls. In the mammary gland, E(2) (either dose) or GEN increased proliferation and PR expression. Serum levels of luteinizing hormone were decreased by E(2) (both doses) but not by GEN.

CONCLUSIONS

In summary, E(2) and GEN share many effects in the studied organs, particularly in the vagina, uterus, and mammary gland but not in the hypothalamo/pituitary unit.

Histologic changes in ovary, uterus, vagina, and mammary gland of mature beagle dogs treated with the SERM idoxifene

BACKGROUND

Idoxifene is a selective estrogen receptor modulator similar to tamoxifen but is no longer in pharmaceutical development due to adverse genitourinary effects in the clinic. Histologic observations of the reproductive system and mammary glands are presented from female dogs treated with idoxifene for up to 12 months.

METHODS

Studies were conducted as part of regulatory requirements to support clinical development. Idoxifene was given orally by capsule, once daily, for 1, 6, or 12 months to female Beagle dogs (n = 3 or 4/group) aged 11-14 months (start of dosing) at dosages 0, 0.03, 0.3, 1.5, or 3 mg/kg/day. Evaluations included the following: clinical observations, hematology, hemostasis, chemistry, toxicokinetics, and histology.

RESULTS

Dose- and time-dependent findings were present in dogs given > or = 0.03 mg/kg/day and included abnormal vaginal discharge, minor increases of platelet and neutrophil counts, and microscopic observations in the ovary (atrophy and mesothelial [ovarian surface epithelium] hyperplasia), endometrium (edema, inflammation, glandular atrophy, squamous metaplasia, increased collagen), myometrium (edema, increased collagen), vagina (squamous hyperplasia, keratinization), and mammary gland (atrophy).

CONCLUSION

Dogs given idoxifene exhibited estrogenic effects in ovary, uterus, and vagina but antiestrogenic effects in endometrial and mammary glands consistent with several observations in clinical trials in post-menopausal women treated with triphenylethylenes.

The bone-protective effect of the phytoestrogen genistein is mediated via ER alpha-dependent mechanisms and strongly enhanced by physical activity

Reduced estrogen levels occurring during menopause in women are accompanied by a variety of disorders, e.g. hot flushes, depressions, osteoporosis, increase in body weight and reduced movement drive. The phytoestrogen genistein (GEN) has been demonstrated to have a significant bone-protective potency. In order to study the ER subtype-specific effects of this phytoestrogen on bone in an animal model, ovariectomized (OVX) female Wistar rats were either treated with 17beta-estradiol (E(2)) (4 microg/kg/day), the ER alpha-specific agonist (ALPHA) 16 alpha-LE(2) (10 microg/kg/day), the ER beta-specific agonist (BETA) 8 beta-VE(2) (100 microg/kg/day) or GEN (10 mg/kg/day) for 3 weeks. Vehicle-treated OVX animals served as controls. All animals had the opportunity of voluntary wheel running. Movement activity, changes of body weight and trabecular bone mineral density (BMD) in the tibia were analyzed. E(2) and ALPHA treatment, but not treatment with BETA, significantly increased the movement activity of OVX rats. Treatment with GEN resulted in a significant decrease of movement activity as compared to OVX animals. Bone mineral density in the trabecular area of the tibia and the expression of bone morphogenetic protein-2 (BMP-2) were significantly reduced in OVX- and BETA-treated rats as compared to rats substituted with E(2), ALPHA and GEN. The bone-protective effect of ALPHA was antagonized by co-treatment with the pure antiestrogen Faslodex (ICI). In order to distinguish hormone-dependent effects from those of exercise, we performed an additional experiment where the animals had no opportunity of wheel running. The results demonstrate that physically inactive rats have a stronger decrease of bone mineral density than physically active animals. Very surprisingly, our data demonstrate that GEN has no bone-protective activity in the absence of physical activity. In contrast, ALPHA and E(2) are bone-protective in the presence and absence of physical activity. In conclusion, our data provide evidence that the effects of E(2) on body weight, movement drive and protection of bone mineral density are mediated via ER alpha, whereas activation of ER beta has only a limited effect. Our data also indicate that the bone-protective effects of GEN may be mediated via ER alpha-dependent mechanisms and that physical activity has a strong impact on the bone-protective potency of this phytoestrogen.