Tissue-selective estrogen complexes for postmenopausal women

Hormonal Therapies in Multiple Sclerosis: a Review of Clinical Data

PURPOSE OF REVIEW

Given the potential for exogenous hormones to influence risk and course of MS, this narrative review aims to summarize current knowledge from observational and interventional studies of exogenous hormones in humans with MS.

RECENT FINDINGS

Large randomized clinical trials for combined oral contraceptives and estriol both show modest effect on inflammatory activity, with the latter showing potential neuroprotective effect. After fertility treatment, large actively treated cohorts have not confirmed any elevated risk of relapse. Preclinical data suggest that androgens, selective estrogen receptor modulators (SERMs), and selective androgen receptor modulators (SARMs) may be neuroprotective but clinical data are lacking. Gender affirming treatment, particularly estrogen in trans-women, could possibly be associated with elevated risk of inflammation. For women with MS entering menopause, hormone therapy appears safe during the appropriate menopausal window, but its long-term effects on neuroprotection are unknown. Exogenous hormones, used in varied doses and for diverse indications, have variable effects on MS risk, inflammatory activity, and neuroprotection. Large randomized trials are needed before it is possible to determine the true effect of exogenous hormones in a condition as complex as MS.

Icariin ameliorates estrogen-deficiency induced bone loss by enhancing IGF-I signaling via its crosstalk with non-genomic ERα signaling

BACKGROUND

Rapid, non-genomic estrogen receptor (ER) signaling plays an integral role in mediating the tissue selective properties of ER modulators. Icariin, a bone bioactive flavonoid, has been reported to selectively activate non-genomic ERα signaling in in vitro and in vivo studies.

PURPOSE

The mechanisms underlying the estrogen-like bone protective effects of icariin are not fully understood, especially those that are related to insulin-like growth factor I (IGF-1) signaling. The bone protective effects of icariin were investigated in female mature ovariectomized (OVX) rats and the signaling of IGF-IR- ERα cross-talk was determined in osteoblastic cells.

STUDY DESIGN AND METHODS

Icariin at 3 different dosages (50, 500 and 3000 ppm) were orally administrated to rats for 3 months through daily intake of phytoestrogen-free animal diets containing icariin. Bone marrow stromal cells (BMSCs) and osteoclast precursors from femurs were harvested for experiments and RNA-sequencing. The interactions between IGF-IR and non-genomic ERα signaling were examined in pre-osteoblastic MC3T3-E1 cells and mature osteoblasts differentiated from BMSCs.

RESULTS

Our results show that chronic administration of icariin to OVX rats significantly protected them against bone loss at the long bone and lumbar spine without inducing any uterotrophic effects. Ex vivo studies using BMSCs and osteoclast precursors confirmed the stimulatory effects of icariin on osteoblastogenesis and its inhibitory effects on osteoclastogenesis, respectively. RNA-sequencing analysis of mRNA from BMSCs revealed that icariin at 500 ppm significantly altered IGF-1 signaling as well as PI3K-Akt pathways. Our results demonstrated for the first time the rapid induction of interactions between IGF-IR and ERα as well as IGF-IR signaling and the downstream Akt phosphorylation by icariin in MC3T3-E1 cells. The activation of ERα and Akt phosphorylation by icariin in MC3T3-E1 cells and the osteogenic effects of icariin on ALP activity in mature osteoblasts were shown to be IGF-IR-dependent.

CONCLUSION

Our findings reveal that icariin activates both ERα and Akt via enhancing rapid induction of IGF-1 signaling in osteoblastic cells for osteogenesis and might be regarded as a novel pathway-selective phytoestrogen for management of postmenopausal osteoporosis.

Sex steroids and autoimmune rheumatic diseases: state of the art

In autoimmune rheumatic diseases, oestrogens can stimulate certain immune responses (including effects on B cells and innate immunity), but can also have dose-related anti-inflammatory effects on T cells, macrophages and other immune cells. By contrast, androgens and progesterone have predominantly immunosuppressive and anti-inflammatory effects. Hormone replacement therapies and oral contraception (and also pregnancy) enhance or decrease the severity of autoimmune rheumatic diseases at a genetic or epigenetic level. Serum androgen concentrations are often low in men and in women with autoimmune rheumatic diseases, suggesting that androgen-like compounds might be a promising therapeutic approach. However, androgen-to-oestrogen conversion (known as intracrinology) is enhanced in inflamed tissues, such as those present in patients with autoimmune rheumatic diseases. In addition, it is becoming evident that the gut microbiota differs between the sexes (known as the microgenderome) and leads to sex-dependent genetic and epigenetic changes in gastrointestinal inflammation, systemic immunity and, potentially, susceptibility to autoimmune or inflammatory rheumatic diseases. Future clinical research needs to focus on the therapeutic use of androgens and progestins or their downstream signalling cascades and on new oestrogenic compounds such as tissue-selective oestrogen complex to modulate altered immune responses.

Beyond estrogen: advances in tissue selective estrogen complexes and selective estrogen receptor modulators

Selective estrogen receptor modulators (SERMs) are synthetic non-steroidal agents which have variable estrogen agonist and antagonist activities in different target tissues. Tamoxifen is an anti-estrogen in the breast used for treatment and prevention of breast cancer, with estrogen agonist activity in the uterus. Raloxifene prevents and treats osteoporosis and prevents breast cancer, and can be safely combined with vaginal but not systemic estrogen. The tissue selective estrogen complex combines conjugated equine estrogens (CEE) with the SERM bazedoxifene (BZA). The five Selective Estrogen Menopause and Response to Therapy studies, with up to 2 years of data, demonstrated that CEE/BZA 0.45 mg/BZA 20 mg improved vasomotor symptoms and vulvovaginal atrophy, prevented bone loss, and was neutral on breast tenderness, breast density, with breast cancer incidence similar to placebo. Protection against estrogen-induced endometrial hyperplasia and cancer was found, with similar amenorrhea rates to placebo. Ospemifene is approved to treat dyspareunia, with potential benefits on bone and the breast, while lasofoxifene is being developed to treat resistant estrogen receptor-positive breast cancer in women. Estetrol is an estrogen synthesized exclusively during pregnancy by the human fetal liver and initially considered a weak estrogen, but it appears to have dual weak estrogenic/anti-estrogenic features.

Emerging therapeutic targets for osteoporosis

Introduction: Osteoporosis is a chronic, skeletal disorder characterized by compromised bone strength and increased fracture risk; it affects 50% of women and 20% of men. In the past two decades, there have been substantial improvements in the pharmacotherapy of osteoporosis which have yielded potent inhibitors of bone resorption or stimulators of bone formation.Areas covered: This review discusses newly identified targets and pathways and conceptual approaches to the prevention of multiple age-related disorders. Furthermore, it summarizes existing therapeutic strategies for osteoporosis.Expert opinion: Our enhanced understanding of bone biology and the reciprocal interactions between bone and other tissues have allowed the identification of new targets that may facilitate the development of novel drugs. These drugs will hopefully achieve the uncoupling of bone formation from resorption and possibly exert a dual anabolic and antiresorptive effect on bone. Alas, limitations regarding adherence, efficacy on nonvertebral fracture prevention and the long-term adverse events still exist for currently available therapeutics. Moreover, the efficacy of most agents is limited by the tight coupling of osteoblasts and osteoclasts; hence the reduction of bone resorption invariably reduces bone formation, and vice versa. This field is very much 'a work in progress.'

Sexual Health in Menopause

Sexual function worsens with advancing menopause status. The most frequently reported symptoms include low sexual desire (40–55%), poor lubrication (25–30%) and dyspareunia (12–45%), one of the complications of genitourinary syndrome of menopause (GSM). Declining levels of sex steroids (estrogens and androgens) play a major role in the impairment of sexual response; however, psychological and relational changes related with aging and an increase in metabolic and cardiovascular comorbidities should also be taken into account. Although first-line therapeutic strategies for menopause-related sexual dysfunction aim at addressing modifiable factors, many hormonal and non-hormonal, local and systemic treatment options are currently available. Treatment should be individualized, taking into account the severity of symptoms, potential adverse effects and personal preferences.

Effects of conjugated estrogen and bazedoxifene on hemostasis and thrombosis in mice

Estrogen-progestin therapy was previously considered as the standard of care for managing bothersome symptoms associated with menopause, but it increases risks of breast cancer and of thromboembolism. The combination of conjugated estrogen (CE) with bazedoxifene (BZA) named tissue-selective estrogen complex (TSEC) was designed to minimize or even abrogate the undesirable effects on breast, while maintaining the beneficial effects such as prevention of osteoporosis and suppression of climacteric symptoms. The risk on thromboembolism associated with TSEC is unknown, although the clinical available data are reassuring. The aim of this study was to define the impact of a chronic administration of CE, BZA or CE + BZA on hemostasis and thrombosis in ovariectomized mice. As expected, CE, but not BZA neither CE + BZA, induced uterine and vagina hypertrophy. As previously demonstrated for 17β-estradiol (E2), we found that CE (i) increased tail-bleeding time, (ii) prevented occlusive thrombus formation in injured carotid artery and (iii) protected against collagen/epinephrine-induced thromboembolism. Thus, whereas BZA antagonized CE action on reproductive tissues, it had no impact on the effect of CE on hemostasis, thromboembolism and arterial thrombosis in mice. CE + BZA shared the anti-thrombotic actions of CE in these mouse models. If a similar process is at work in women, CE combined with BZA could contribute to minimize the risk of thrombosis associated with hormone replacement therapy.

Selective Estrogen Receptor Modulators Enhance CNS Remyelination Independent of Estrogen Receptors

A significant unmet need for patients with multiple sclerosis (MS) is the lack of U.S. Food and Drug Administration (FDA)-approved remyelinating therapies. We have identified a compelling remyelinating agent, bazedoxifene (BZA), a European Medicines Agency (EMA)-approved (and FDA-approved in combination with conjugated estrogens) selective estrogen receptor (ER) modulator (SERM) that could move quickly from bench to bedside. This therapy stands out as a tolerable alternative to previously identified remyelinating agents and other candidates within this family. Using an unbiased high-throughput screen, with subsequent validation in both murine and human oligodendrocyte precursor cells (OPCs) and coculture systems, we find that BZA enhances differentiation of OPCs into functional oligodendrocytes. Using an in vivo murine model of focal demyelination, we find that BZA enhances OPC differentiation and remyelination. Of critical importance, we find that BZA acts independently of its presumed target, the ER, in both in vitro and in vivo systems. Using a massive computational data integration approach, we independently identify six possible candidate targets through which SERMs may mediate their effect on remyelination. Of particular interest, we identify EBP (encoding 3β-hydroxysteroid-Δ8,Δ7-isomerase), a key enzyme in the cholesterol biosynthesis pathway, which was previously implicated as a target for remyelination. These findings provide valuable insights into the implications for SERMs in remyelination for MS and hormonal research at large.SIGNIFICANCE STATEMENT Therapeutics targeted at remyelination failure, which results in axonal degeneration and ultimately disease progression, represent a large unmet need in the multiple sclerosis (MS) population. Here, we have validated a tolerable European Medicines Agency-approved (U.S. Food and Drug Administration-approved in combination with conjugated estrogens) selective estrogen receptor (ER) modulator (SERM), bazedoxifene (BZA), as a potent agent of oligodendrocyte precursor cell (OPC) differentiation and remyelination. SERMs, which were developed as nuclear ER-α and ER-β agonists/antagonists, have previously been implicated in remyelination and neuroprotection, following a heavy focus on estrogens with underwhelming and conflicting results. We show that nuclear ERs are not required for SERMs to mediate their potent effects on OPC differentiation and remyelination in vivo and highlight EBP, an enzyme in the cholesterol biosynthesis pathway that could potentially act as a target for SERMs.

[Towards an optimization of the modulation of the estrogen receptor during menopausal hormonal therapy]

Women now live more than a third of their lives after the onset of menopause. The decline in endogenous estrogen production during this period is accompanied by functional disorders that affect quality of life. These symptoms may be relieved by menopausal hormone therapy (MHT) initially based on the administration of equine conjugated estrogens (mainly in the United States, oral route) or the natural estrogen, 17β-estradiol (in Europe, transdermal route). Estrogen receptor α (ERα), but not ERβ, mediates most of the physiological effects of estrogens. ERα belongs to the superfamily of nuclear receptors and regulates the transcription of genes via its activation functions AF1 and AF2. In addition to these classical genomic actions, estrogens can activate a subpopulation of ERα present at the cell membrane and thereby induce rapid signals. In this review, we will summarize the evolution of MHTs in last decades, as well as treatments that use various selective estrogen receptor modulators (SERMs). Next, we will describe recent advances in the understanding of the mechanisms of estrogen action, in particular the respective roles of nuclear and membrane ERα as well as the potential implications for future therapies.

What do TSECs provide in the menopausal hormone therapy?

Tissue-selective estrogen complex (TSEC) is projected as a progestogen-free option for the treatment of estrogen deficiency symptoms in postmenopausal, non-hysterectomized women. TSEC combines the benefits of estrogen with a selective estrogen receptor modulator (SERM), in this case bazedoxifene acetate (BZA), which has an antagonistic effect on the endometrium, thus avoiding the use of progestins. The authorized TSEC combination (conjugated estrogens [CE] 0.45 mg/BZA 20 mg) for the alleviation of vasomotor symptoms has been demonstrated in randomized clinical trials compared with placebo or menopausal hormone therapy (MHT). In addition, TSEC has shown improvements in quality of life and vaginal atrophy. In respect to MHT using progestins, the benefits of TSEC are found mainly in the bleeding pattern, amenorrhea rate, and reduction in mammary repercussion (i.e., breast tenderness and radiological density). The objective of this guide will be to analyze the efficacy and safety of TSEC consisting of CE/BZA in postmenopausal women.

The antagonist properties of Bazedoxifene after acute treatment are shifted to stimulatory action after chronic exposure in the liver but not in the uterus

A promising alternative to conventional hormone therapy for postmenopausal symptoms is treatment combining Bazedoxifene (BZA), a third-generation selective estrogen receptor modulator (SERM), and conjugated equine estrogen (CE). This combination is also known as a tissue-selective estrogen complex (TSEC). Understanding the tissue-specific actions of SERMs and the TSEC remains a major challenge to try to predict their clinical effects. The aim of this study was to compare acute versus chronic treatment with BZA, CE or CE + BZA in two major targets of estrogens, the uterus and the liver. In these two tissues, acute treatment with CE, but not with BZA, induced similar gene expression change than the most important endogenous estrogen, 17-β estradiol (E2). Acute induction of gene expression by E2 or by CE was antagonized by the addition of BZA. Concomitantly, BZA alone or in combination with E2 or CE induced a partial degradation of ERα protein after acute exposure. In uterus, chronic treatment of BZA alone had no impact on tissue weight gain or on epithelial cell proliferation, and also antagonized CE-effect in uterus, thereby mimicking the acute effect. By contrast, in the liver, chronic BZA and CE + BZA elicited agonistic transcriptional effects similar to those of CE alone. In addition, at variance to BZA acute effect, no change in ERα protein abundance was observed after chronic treatment in this tissue. These experimental in vivo data highlight a new aspect of the time-dependent tissue-specific action of BZA or TSEC, i.e. they can act acutely as antagonists but become agonists after chronic treatment. This shift was observed in liver tissue, but not in proliferative sex target such as the uterus.

Ospemifene's effects on lipids and coagulation factors: a post hoc analysis of phase 2 and 3 clinical trial data

Objective:

To evaluate the effect of ospemifene 60 mg on the lipid and coagulation parameters of postmenopausal women using data from five phase 2 and 3 clinical trials.

Methods:

Data for lipids and coagulation factors for 2,166 postmenopausal women were pooled from five randomized, placebo-controlled studies. Lipid and coagulation parameters included in this analysis were total cholesterol, high-density lipoproteins (HDL), low-density lipoproteins (LDL), triglycerides, activated partial thromboplastin time (aPTT), fibrinogen, antithrombin antigen, protein C Ag, and protein S Ag free.

Results:

Mean percent changes in HDL and LDL were significantly greater with ospemifene versus placebo at month 3 (HDL: 4.4% vs 0.2%; LDL: −5.2% vs 2.4%), month 6 (HDL: 5.1% vs 1.5%; LDL: −6.7% vs 2.4%), and month 12 (HDL: 2.3% vs −1.9%; LDL: −7.0% vs −2.1%; P < 0.05, for all comparisons). Ospemifene significantly reduced total cholesterol at 6 months (−1.8% vs 1.6%; P = 0.0345 versus placebo), and changes in triglycerides with ospemifene were similar to placebo at all three time points. In subgroup analyses based on age, body mass index, and baseline triglyceride level, ospemifene increased HDL and decreased LDL, but had no significant effect on total cholesterol and triglycerides relative to placebo. Ospemifene significantly improved fibrinogen and protein C antigen levels relative to placebo at months 3 (−8.7% vs −0.8% and −2.7% vs 0.5%, respectively), 6 (−6.0% vs 6.7% and −3.6 vs 8.0%), and 12 (−8.7% vs 7.3% and −4.5% vs 6.6%; P < 0.01, for all). The levels of all coagulation factors remained within the normal range throughout the studies.

Conclusion:

Ospemifene 60 mg does not have a detrimental effect on lipid and coagulation parameters of postmenopausal women with up to 12 months of use.

Towards optimization of estrogen receptor modulation in medicine

Women now spend more than one-third of their lives in the postmenopausal years, and the decline of endogenous estrogen production during menopause is accompanied by a series of functional disorders that affect the quality of life. These symptoms could be alleviated or even totally suppressed by menopausal hormone therapy (MHT), initially based on natural estrogens extracted from the urine of pregnant mares (mainly in the USA, using the oral route) and later from the synthesis of the natural estrogen, 17β-estradiol (mainly in Europe, in particular using the transdermal route). Estrogen receptor (ER) α is the main receptor mediating the physiological effects of estrogens. ERα belongs to the nuclear receptor superfamily and activates gene transcription in a time and tissue-specific manner through two distinct activation functions (AF), AF1 and AF2. In addition to these classical genomic actions, ERα also mediates membrane initiated signaling enabling rapid actions of estrogen, potentially along or in interaction with other receptors. Here, we provide a brief historical overview of MHT, and we then highlight recent advances in the characterization of new treatments based on the association of estrogens with selective estrogen receptor modulators (SERMs) or on the modulation of nuclear or membrane ERα.

Enhanced cytotoxicity and apoptosis by raloxifene in combination with estrogen and methotrexate in human endometrial stromal cells

Endometrial hyperplasia is a condition that may lead to the development of endometrial carcinoma. Initially, changes of the endometrium are caused by the estrogen's hyperstimulation that may lead to the development of an irregular bleeding and the infertility problems. Therapy of endometrial hyperplasia is limited to medical and surgical approaches. During the past decade, the new types of drugs were developed for the treatment of the endometrial hyperplasia. Here, for the first time, we investigated the cytotoxic effects of the various combinations of estrogen, raloxifene, and methotrexate in human ThESC cell line as a possible potential treatment of the endometrial hyperplasia. Our aim was to investigate and to determine the most efficient combination of investigated drugs in ThESC cells during 24-hr period using MTT assay, FACS analysis, and immunofluorescence staining. Our results demonstrated that the combination of raloxifene with methotrexate efficiently induced both the cytotoxicity and apoptosis in ThESC cells when compared to their single effect, as well as to the effect of combined treatment of raloxifene with estrogen. The application of the low doses of methotrexate combined with raloxifene offers all advantages of a potential beneficial antitumor match in cancer chemoprevention and therapy.

AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY POSITION STATEMENT ON MENOPAUSE-2017 UPDATE

EXECUTIVE SUMMARY This American Association of Clinical Endocrinologists (AACE)/American College of Endocrinology (ACE) Position Statement is designed to update the previous menopause clinical practice guidelines published in 2011 but does not replace them. The current document reviews new clinical trials published since then as well as new information regarding possible risks and benefits of therapies available for the treatment of menopausal symptoms. AACE reinforces the recommendations made in its previous guidelines and provides additional recommendations on the basis of new data. A summary regarding this position statement is listed below: New information available from randomized clinical trials and epidemiologic studies reported after 2011 was critically reviewed. No previous recommendations from the 2011 menopause clinical practice guidelines have been reversed or changed. Newer information enhances AACE's guidance for the use of hormone therapy in different subsets of women. Newer information helps to support the use of various types of estrogens, selective estrogen-receptor modulators (SERMs), and progesterone, as well as the route of delivery. Newer information supports the previous recommendation against the use of bioidentical hormones. The use of nonhormonal therapies for the symptomatic relief of menopausal symptoms is supported. Newer information enhances AACE's guidance for the use of hormone therapy in different subsets of women. Newer information helps to support the use of various types of estrogens, SERMs, and progesterone, as well as the route of delivery. Newer information supports the previous recommendation against the use of bioidentical hormones. The use of nonhormonal therapies for the symptomatic relief of menopausal symptoms is supported. New recommendations in this position statement include: 1.

RECOMMENDATION

the use of menopausal hormone therapy in symptomatic postmenopausal women should be based on consideration of all risk factors for cardiovascular disease, age, and time from menopause. 2.

RECOMMENDATION

the use of transdermal as compared with oral estrogen preparations may be considered less likely to produce thrombotic risk and perhaps the risk of stroke and coronary artery disease. 3.

RECOMMENDATION

when the use of progesterone is necessary, micronized progesterone is considered the safer alternative. 4.

RECOMMENDATION

in symptomatic menopausal women who are at significant risk from the use of hormone replacement therapy, the use of selective serotonin re-uptake inhibitors and possibly other nonhormonal agents may offer significant symptom relief. 5.

RECOMMENDATION

AACE does not recommend use of bioidentical hormone therapy. 6.

RECOMMENDATION

AACE fully supports the recommendations of the Comité de l'Évolution des Pratiques en Oncologie regarding the management of menopause in women with breast cancer. 7.

RECOMMENDATION

HRT is not recommended for the prevention of diabetes. 8.

RECOMMENDATION

In women with previously diagnosed diabetes, the use of HRT should be individualized, taking in to account age, metabolic, and cardiovascular risk factors.

ABBREVIATIONS

AACE = American Association of Clinical Endocrinologists; ACE = American College of Endocrinology; BMI = body mass index; CAC = coronary artery calcification; CEE = conjugated equine estrogen; CEPO = Comité de l'Évolution des Pratiques en Oncologie; CAD = coronary artery disease; CIMT = carotid intima media thickness; CVD = cardiovascular disease; FDA = Food and Drug Administration; HDL = high-density lipoprotein; HRT = hormone replacement therapy; HT = hypertension; KEEPS = Kronos Early Estrogen Prevention Study; LDL = low-density lipoprotein; MBS = metabolic syndrome; MPA = medroxyprogesterone acetate; RR = relative risk; SERM = selective estrogen-receptor modulator; SSRI = selective serotonin re-uptake inhibitor; VTE = venous thrombo-embolism; WHI = Women's Health Initiative.

Membrane and Nuclear Estrogen Receptor Alpha Actions: From Tissue Specificity to Medical Implications

Estrogen receptor alpha (ERα) has been recognized now for several decades as playing a key role in reproduction and exerting functions in numerous nonreproductive tissues. In this review, we attempt to summarize the in vitro studies that are the basis of our current understanding of the mechanisms of action of ERα as a nuclear receptor and the key roles played by its two activation functions (AFs) in its transcriptional activities. We then depict the consequences of the selective inactivation of these AFs in mouse models, focusing on the prominent roles played by ERα in the reproductive tract and in the vascular system. Evidence has accumulated over the two last decades that ERα is also associated with the plasma membrane and activates non-nuclear signaling from this site. These rapid/nongenomic/membrane-initiated steroid signals (MISS) have been characterized in a variety of cell lines, and in particular in endothelial cells. The development of selective pharmacological tools that specifically activate MISS and the generation of mice expressing an ERα protein impeded for membrane localization have begun to unravel the physiological role of MISS in vivo. Finally, we discuss novel perspectives for the design of tissue-selective ER modulators based on the integration of the physiological and pathophysiological roles of MISS actions of estrogens.

An Overview of the Clinical Efficacy and Safety of Tissue Selective Estrogen Complex: From the Selective Estrogens, Menopause, and Response to Therapy (SMART) Trials

Hormone therapy (HT) is the most effective treatment for menopausal symptoms, and reduces both spinal and non-spinal postmenopausal osteoporotic fractures. However, a Women's Health Initiative (WHI) trial revealed that progestin-containing HT is associated with higher incidences of breast cancer and coronary heart disease than those associated with placebo. Tissue selective estrogen complex (TSEC) is a novel progestin-free HT option composed of conjugated estrogens (CE) and a selective estrogen receptor modulator. CE at a dose of 0.45 mg combined with 20 mg of bazedoxifene was the first TSEC medication approved in the United States and Korea for women with moderate to severe menopause-related vasomotor symptoms (VMS) and for preventing postmenopausal osteoporosis. This review summarizes the clinical efficacy, safety, and tolerability of TSEC as obtained from the five SMART clinical trials.

The Tissue-Selective Estrogen Complex (Bazedoxifene/Conjugated Estrogens) for the Treatment of Menopause

The tissue-selective estrogen complex (TSEC) pairs conjugated estrogens (CE) with a selective estrogen receptor modulator (SERM), bazedoxifene acetate (BZA). A 2-year treatment with the TSEC improved vasomotor symptoms, quality of life, and vaginal atrophy in healthy postmenopausal women. In addition, the TSEC prevented vertebral and hip bone loss without increasing mammographic density, breast tenderness, the risk of myocardial infarction, stroke, or venous thromboembolism. Finally, the BZA 20 mg/CE 0.45 mg dose did not increase the risk of endometrial hyperplasia. Based on these findings, the TSEC can be considered as a first-line treatment for symptomatic postmenopausal women.

Role of ERαMISS in the Effect of Estradiol on Cancellous and Cortical Femoral Bone in Growing Female Mice

Estrogen receptor-α (ERα) acts primarily in the nucleus as a transcription factor involving two activation functions, AF1 and AF2, but it can also induce membrane-initiated steroid signaling (MISS) through the modulation of various kinase activities and/or secondary messenger levels. Previous work has demonstrated that nuclear ERα is required for the protective effect of the estrogen 17β-estradiol (E2), whereas the selective activation of ERαMISS is sufficient to confer protection in cortical but not cancellous bone. The aim of this study was to define whether ERαMISS is necessary for the beneficial actions of chronic E2 exposure on bone. We used a mouse model in which ERα membrane localization had been abrogated due to a point mutation of the palmitoylation site of ERα (ERα-C451A). Alterations of the sex hormones in ERα-C451A precluded the interpretation of bone parameters that were thus analyzed on ovariectomized and supplemented or not with E2 (8 μg/kg/d) to circumvent this bias. We found the beneficial action of E2 on femoral bone mineral density as well as in both cortical and cancellous bone was decreased in ERα-C451A mice compared with their wild-type littermates. Histological and biochemical approaches concurred with the results from bone marrow chimeras to demonstrate that ERαMISS signaling affects the osteoblast but not the osteoclast lineage in response to E2. Thus, in contrast to the uterine and endothelial effects of E2 that are specifically mediated by nuclear ERα and ERαMISS effects, respectively, bone protection is dependent on both, underlining the exquisite tissue-specific actions and interactions of membrane and nuclear ERα.

Re-adopting classical nuclear receptors by cholesterol metabolites

Since the first cloning of the human estrogen receptor (ER) α in 1986 and the subsequent cloning of human ERβ, there has been extensive investigation of the role of estrogen/ER. Estrogens/ER play important roles not only in sexual development and reproduction but also in a variety of other functions in multiple tissues. Selective Estrogen Receptor Modulators (SERMs) are ER lignds that act as agonists or antagonists depending on the target genes and tissues, and until recently, only synthetic SERMs have been recognized. However, the discovery of the first endogenous SERM, 27-hydroxycholesterol (27HC), opened a new dimension of ER action in health and disease. In addition to the identification of 27HC as a SERM, oxysterols have been recently demonstrated as indirect modulators of ER through interaction with the nuclear receptor Liver X Receptor (LXR) β. In this review, the recent progress on these novel roles of oxysterols in ER modulation is summarized.

Selective Estrogen Receptor Modulators and the Tissue-Selective Estrogen Complex: Analysis of Cell Type-Specific Effects Using In Vivo Imaging of a Reporter Mouse Model

Selective estrogen receptor modulators (SERMs) are a class of compounds that act differentially on the estrogen receptor (ER) in various tissues with a mixed agonist/antagonistic activity (agonistic in some tissues while antagonist in others). This peculiarity represents a challenge for developing new hormone replacement therapies (HRTs) and highlights the need of new tools to evaluate the specific effects of a given SERM in different organs/tissues of an entire organism and with time. Reporter mice represent invaluable tools in pharmacology to analyze specific signaling in physiological conditions and monitor the effects of drugs acting on these signals in a spatio-temporal dimension. Here, we describe an in vivo protocol to examine the effects of different SERMs on estrogen receptor activity by using the ERE-Luc reporter model, a mouse that reports ER transcriptional activity.

Retraction: Protective effects of bazedoxifene paired with conjugated estrogens on pancreatic β-cell dysfunction

This article has been retracted by the Editorial Committee of The Pharmaceutical Society of Japan because it contains scientific misconduct. Although the data published in this article were generated in part by the first author, the authors violated authorship and sponsorship protocol.

Menopausal Hormone Therapy: Current Considerations

Menopausal hormone therapy (MHT) is the most effective treatment for vasomotor and vaginal symptoms. Today, symptomatic women younger than 60 years of age or less than 10 years since onset of menopause yield the greatest benefit of MHT with the lowest risks when compared with older women remote from menopause. Careful assessment before initiating therapy includes severity of bothersome symptoms, treatment preferences, medical history, presence of contraindications to MHT, and personal risk of cardiovascular disease and breast cancer. Considerations of type of MHT, dosing, and route of administration, and recommendations regarding duration of therapy are discussed.

The Recent Review of the Genitourinary Syndrome of Menopause

The genitourinary syndrome of menopause (GSM) is a new term that describes various menopausal symptoms and signs including not only genital symptoms (dryness, burning, and irritation), and sexual symptoms (lack of lubrication, discomfort or pain, and impaired function, but also urinary symptoms (urgency, dysuria, and recurrent urinary tract infections). The terms vulvovaginal atrophy and atrophic vaginitis, which were generally used until recently, had a limitation because they did not cover the full spectrum of symptoms and did not imply that the symptoms are related to a decreased estrogen level in menopause. Since the GSM may have a profound negative impact on the quality of life of postmenopausal women, women should be made aware of these problems and treated with an appropriate effective therapy. Thus, in this review we introduce new terminology and discuss the importance of comprehension of GSM and the necessity of active treatment of this syndrome in postmenopausal women.

Effects of genistein in combination with conjugated estrogens on endometrial hyperplasia and metabolic dysfunction in ovariectomized mice

Tissue-selective estrogen complex (TSEC), which combines a selective estrogen receptor modulator (SERM) with one or more estrogens, is a novel approach to menopausal therapy. It has been demonstrated that the phytoestrogen genistein (GEN) exhibits mixed estrogen receptor agonist and antagonist activity, suggesting that GEN may have potential for use as a natural SERM. We evaluated, for the first time, the effects of GEN, conjugated estrogens (CE), and their pairing effects as a TSEC treatment on estrogen-induced endometrial hyperplasia and metabolic dysfunction in ovariectomized (OVX) mice fed a high-fat diet. CE replacement prevented fat accumulation in the adipose tissue and liver, improved glucose homeostasis, and induced endometrial hyperplasia in OVX mice. GEN at 100 mg/kg showed CE mimetic effects in preventing ovariectomy-induced metabolic dysfunctions without endometrial stimulation. Combination treatments with CE and GEN prevented metabolic dysfunctions more strongly than CE alone, but at both low and high doses, GEN did not reverse CE-induced endometrial hyperplasia. In addition, we found that in a TSEC regimen, a typical SERM raloxifene maintains the metabolic benefits of CE while simultaneously protecting the endometrium in OVX mice. These findings indicate that GEN acts as an estrogen agonist in metabolic regulation, but has no SERM function in the uteri of OVX mice.

Conjugated estrogen/bazedoxifene tablets for the treatment of moderate-to-severe vasomotor symptoms associated with menopause

Conjugated estrogen/bazedoxifene (CE/BZA) therapy represents a new, progestin-free treatment in the management of postmenopausal health. CE/BZA pairs CE with the selective estrogen receptor modulator, BZA. The rationale for the development of CE/BZA was that BZA, acting primarily as a selective estrogen receptor degrader in uterine and breast tissue, would sufficiently inhibit the proliferative effects of CE on the endometrium. The absence of a progestin would reduce the incidence of uterine bleeding, breast pain and increased breast density associated with progestin-containing hormone therapy. CE/BZA has been evaluated in five multicenter, randomized, double-blind, placebo-controlled, and active-controlled Phase III trials known as the SMART trials. CE/BZA has been shown to maintain the established benefits of estrogen therapy for treatment of vasomotor symptoms and prevention of a loss in bone mineral density (bone mass), while minimizing certain estrogenic effects, particularly in the uterine endometrium and breast.

Selective estrogen receptor modulators (SERMs): a review of clinical data

SERMs represent a diverse group of molecules with varying levels of estrogenic agonist and antagonist activity in target tissues. SERMs have a long regulatory approval history and have been studied for a variety of therapeutic indications. The clinical effects of SERMs have been evaluated in a large number of phase 3 clinical trials. Many of the available SERMs have proved to be effective as chemo-preventive agents and treatments for breast cancer and a number are useful for the prevention and treatment of osteoporosis. The endometrial effect of SERMs has been a key differentiator in clinical practice and a major hurdle for regulatory approval. The effect of SERMs in the vagina also represents a major distinction among different SERMs. This review summarized key clinical finding of SERMs in different target tissues.

Supplementing with Opuntia ficus-indica Mill and Dioscorea nipponica Makino extracts synergistically attenuates menopausal symptoms in estrogen-deficient rats

ETHNOPHARMACOLOGICAL RELEVANCE

Prickly pear cactus grown in Korea (Opuntia ficus-indica Mill, KC) and Buchema (Dioscorea nipponica Makino, B) have been traditionally used in East Asia and South America to treat various metabolic diseases. The aim of the present study was to determine whether the extracts of KC, B, and KC+B can prevent the impairments of energy, glucose, lipid and bone homeostasis in estrogen-deficient ovariectomized (OVX) rats and to explore their mechanisms.

MATERIALS AND METHODS

OVX rats were divided into 4 groups and fed high fat diets supplemented with either 3% dextrin (control), 3% KC, 3% B or 1.5% KC+1.5% B. Sham rats were fed 3% dextrin. After 12 weeks of diet consumption, energy, lipid, glucose and bone metabolisms were analyzed and Wnt signaling in the femur and hepatic signaling were determined.

RESULTS

OVX impaired energy, glucose and lipid metabolism and decreased uterine and bone masses. B and KC+B prevented the decrease in energy expenditure, especially from fat oxidation, in OVX rats, but did not affect food intake. KC+B and B reduced body weight and visceral fat levels, as compared to the OVX-control, by decreasing fat synthesis and inhibiting FAS and SREBP-1c expression. KC+B and B prevented the increases in serum lipid levels and insulin resistance by improving hepatic insulin signaling (pIRS→pAkt→pGSK-3β). KC and KC+B also prevented decreases in bone mineral density (BMD) in the femur and lumbar spine in OVX rats. This was related to decreased expressions of bone turnover markers such as serum osteocalcin, alkaline phosphatase (ALP) and bone-specific ALP levels, and increased serum P levels. KC and KC+B upregulated low-density lipoprotein receptor-related protein 5 and β-catenin in OVX rats, but suppressed the expression of dickkopf-related protein 1. B alone improved energy, lipid and glucose homeostasis, but not bone loss, whereas KC alone enhanced BMD, but not energy, lipid or glucose homeostasis.

CONCLUSION

KC+B synergistically attenuated impairments of bone, energy, lipid and glucose metabolism by OVX, suggesting potential efficacy of the combination for alleviating menopausal symptoms.

Conjugated estrogens combined with bazedoxifene: the first approved tissue selective estrogen complex therapy

Menopausal therapy with a tissue selective estrogen complex combines estrogens with a selective estrogen receptor modulator, with the goal of blending the desirable effects of estrogens on menopausal symptoms and bone with the tissue selective properties of a selective estrogen receptor modulator. The first tissue selective estrogen complex to receive regulatory approval is a combination of conjugated estrogens (CE) with bazedoxifene (BZA). Clinical trials with CE/BZA in postmenopausal women have shown improvement in vasomotor symptoms, vulvo-vaginal atrophy, and bone mineral density, without stimulation of the endometrium or breast tissue, with a generally favorable safety and tolerability profile. CE/BZA represents a new approach to the management of menopausal symptoms in women with a uterus.

Ospemifene for the treatment of dyspareunia associated with vulvar and vaginal atrophy: potential benefits in bone and breast

Ospemifene is a selective estrogen receptor modulator (SERM), or estrogen receptor agonist/antagonist, that was recently approved by the US Food and Drug Administration for the treatment of dyspareunia associated with vulvar and vaginal atrophy, a chronic condition that affects up to 60% of postmenopausal women. Ospemifene is the first and only nonestrogen compound approved for this indication. Compared with other approved SERMs, such as tamoxifen, toremifene, bazedoxifene, and raloxifene, the estrogen-like effects of ospemifene in the vaginal epithelium are unique. This review first discusses the rationale for developing ospemifene, including its mechanism of action, and then focuses on the clinical development of ospemifene for the treatment of dyspareunia associated with vulvar and vaginal atrophy. Included are discussions of the effects of ospemifene on the endometrium, serum lipids, coagulation markers, bone, and breast cancer. In conclusion, ospemifene is a SERM with a unique estrogen agonist/antagonist tissue profile that was recently approved in the US for the treatment of dyspareunia associated with vulvar and vaginal atrophy in postmenopausal women. Ospemifene warrants further clinical investigation for the treatment and prevention of osteoporosis and breast cancer.