Dietary genistein and 17ß-estradiol implants differentially influence locomotor and cognitive functions following transient focal ischemia in middle-aged ovariectomized rats at different lengths of estrogen deprivation.

Genistein possesses estrogenic activity and has been considered a potential replacement for estrogen replacement therapy after menopause. In the current study, we investigated the neuroprotective effects of dietary genistein at varied lengths of estrogen deprivation in middle-aged ovariectomized Sprague-Dawley rats under ischemic conditions. Two weeks of treatment with dietary genistein at 42 mg/kg but not 17ß-estradiol implants improved cognitive flexibility (Morris water maze test) after short-term estrogen deprivation (2 weeks) but not long-term estrogen deprivation (12 weeks). 17ß-estradiol implants but not dietary genistein improved locomotor asymmetry (cylinder test) after long-term but not short-term estrogen deprivation. Dietary genistein but not 17ß-estradiol implant improved early phase motor learning (rotarod test) after long-term estrogen deprivation. Neither 17ß-estradiol implant nor dietary genistein reduced infarct size after either short-term or long-term estrogen deprivation. Genistein, however, reduced ionized calcium-binding adaptor molecule-1 (Iba1) expression, a marker of brain inflammation, at the ipsilateral side of stroke injury after short-term but not long-term estrogen deprivation. This study suggests that the neuroprotective effects of dietary genistein on motor and cognitive functions are distinctly influenced by the length of estrogen deprivation following focal ischemia. SIGNIFICANCE: There is an increasing postmenopausal population opting for homeopathic medicines for the management of menopausal symptoms due to the perceived distrust in estrogen use as hormone replacement. Basic and clinical studies support the notion that early, but not delayed, hormone replacement after menopause is beneficial. Furthermore, evidence suggests that delaying hormone replacement augments the detrimental, rather than the beneficial effects of estrogens. Because of the active consideration of soy isoflavones including genistein as alternatives to estrogen replacement, it is necessary to understand the ramifications of soy isoflavones use when their administration is begun at various times after menopause.

Managing Common Estrogen Deprivation Side Effects in HR+ Breast Cancer: an Evidence-Based Review.

PURPOSE OF REVIEW: The article reviews the consequences of estrogen deprivation during endocrine therapy for breast cancer and provides an update on alternative therapies for the management of symptoms. RECENT FINDINGS: Endocrine therapy has progressed substantially in recent years, and its use is recommended for all breast cancer patients expressing hormone receptors. The main adverse events of this treatment can be controlled with medications and nonpharmacological measures. Antidepressants are effective in controlling vasomotor symptoms. Vaginal discomfort can be treated with local lubricants and pelvic floor physiotherapy, which may help in sexual dysfunction. Pathophysiological mechanisms of musculoskeletal symptoms during aromatase inhibitors treatment are not well understood, but some studies evaluating treatment with duloxetine, yoga, and acupuncture have shown some benefits. For prevention of bone loss, patients with risk factors should be offered bisphosphonates or denosumab. Individualization of treatment is crucial. Consideration should be given to therapy effects on quality of life, and strategies for controlling associated symptoms should be offered.

Does estrogen deprivation affect pelvic floor muscle contractility?

INTRODUCTION AND HYPOTHESIS: Pelvic floor muscle (PFM) function plays a role in pelvic organ support, and estrogen deprivation is commonly seen as a risk factor for pelvic floor dysfunction. This study investigated the association between estrogen deprivation and PFM contractility. METHODS: This was a retrospective study on women attending a tertiary urogynecological unit. The assessment included an interview, POPQ assessment, Modified Oxford Scale (MOS) score, and 4D translabial ultrasound (US) on PFM contraction (PMFC). Hormonal status and details on hormone replacement therapy (HRT) were recorded. Corrected menopausal age was defined as the duration of systemic estrogen deprivation. Offline analysis of stored US volumes was performed to measure the reduction in anteroposterior hiatal diameter and bladder neck elevation on PFMC at a later date. RESULTS: Seven hundred thirty-nine women were seen during the study period. Fifty-three were excluded for missing data, leaving 686. Mean age was 56 (17-89, SD 13.3) years; average BMI was 29 (16-66, SD 6.6) kg/m²; 60.6% (n = 416) were menopausal at a mean duration of 16 (1-56, SD 10.2) years. Forty-nine (7.1%) were currently on systemic HRT, while 104 (15.2%) had used it previously. Mean corrected menopausal age (menopausal age - systemic HRT duration) was 7.4 (0-56, SD 10.0) years. Current local estrogen use ≥ 3 months was reported by 31 (4.5%). Mean PFM contractility measured by MOS was 2 (0-5, SD 1.1,). On multivariate analysis there was no association between menopausal age and PFM contractility. CONCLUSIONS: Estrogen deprivation may not be an independent predictor of pelvic floor muscle contractility.

Estrogen deprivation aggravates intracellular calcium dyshomeostasis in the heart of obese-insulin resistant rats.

The incidence of cardiovascular disease and metabolic syndrome increases after the onset of menopause, giving evidence for the vital role of estrogen. Intracellular calcium [Ca2+ ]i regulation plays an important role in the maintenance of left ventricular (LV) contractile function. Although either estrogen deprivation or obesity has been shown to strongly affect the metabolic status and LV function, the effects of estrogen deprivation on the cardiometabolic status and cardiac [Ca 2+ ]i regulation in the obese-insulin resistant condition have never been investigated. Our hypothesis was that estrogen deprivation aggravates LV dysfunction through the increased impairment of [Ca 2+ ]i homeostasis in obese-insulin resistant rats. Female rats were fed on either a high-fat (HFD, 59.28% fat) or normal (ND, 19.77% fat) diet for 13 weeks. Then, rats were divided into sham (HFS and NDS) operated or ovariectomized (HFO and NDO) groups. Six weeks after surgery, metabolic status, LV function and incidence of [Ca 2+ ]i transients were determined. NDO, HFS, and HFO rats had evidence of obese-insulin resistance indicated by increased body weight with hyperinsulinemia and euglycemia. Although NDO, HFS, and HFO rats had markedly reduced %LV fractional shortening, E/A ratio and decreased [Ca 2+ ]i transient amplitude and decay rate, HFO rats had the most severe impairments. These findings indicate that estrogen deprivation had a strong impact on abnormal LV function through [Ca 2+ ]i regulation. In addition, evidence was found that in obese-insulin resistant rats, estrogen deprivation severely aggravates LV dysfunction via increased impairment of [Ca 2+ ]i homeostasis.

Concurrent neoadjuvant chemotherapy and estrogen deprivation in patients with estrogen receptor-positive, human epidermal growth factor receptor 2-negative breast cancer (CBCSG-036): A randomized, controlled, multicenter trial.

BACKGROUND: The current randomized, controlled, multicenter clinical trial was conducted to investigate the efficacy of concurrent neoadjuvant chemotherapy (NCT) and estrogen deprivation in patients with estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative breast cancer. METHODS: Eligible patients with AJCC stage IIB to stage IIIC, ER-positive, HER2-negative breast cancer were enrolled and randomly assigned to receive NCT with or without estrogen deprivation. The primary endpoint was the objective response rate (ORR). RESULTS: A total of 249 patients were assigned to either neoadjuvant chemoendocrine therapy (NCET) (125 patients) or the NCT group (124 patients). In the intention-to-treat analysis, the ORR was found to be significantly higher in the NCET group compared with the NCT group (84.8% vs 72.6%; odds ratio, 2.11 [95% CI, 1.13-3.95; P = .02). The efficacy of NCET was more prominent in tumors with a higher Ki-67 index (>20%), with an ORR of 91.2% reported in the NCET group versus 68.7% in the NCT group (P = .001). The pathologic complete response and pathological response rates did not differ significantly between the 2 groups. Although there was no significant difference with regard to progression-free survival (PFS) between the 2 groups (P = .188), patients with a higher baseline Ki-67 index appeared to derive a greater PFS benefit from NCET (2-year PFS rate of 91.5% in the NCET group vs 76.5% in the NCT group; P = .058). Adding endocrine agents to NCT did not result in significant differences in adverse events (grade 3 or 4; graded according to National Cancer Institute Common Terminology Criteria for Adverse Events [version 3.0]) between the 2 groups. CONCLUSIONS: The addition of estrogen deprivation to NCT appears to improve the clinical response in patients with ER-positive, HER2-negative breast cancer, especially for those individuals with a higher Ki-67 index. Patients with a higher Ki-67 index might derive more PFS benefit from concurrent neoadjuvant treatment.

Effect of neuromuscular taping on musculoskeletal disorders secondary to the use of aromatase inhibitors in breast cancer survivors: a pragmatic randomised clinical trial.

BACKGROUND: Aromatase inhibitors reduce breast cancer recurrence rates in postmenopausal women by about 30% compared with tamoxifen while treatments differ. Unfortunately, nearly half of women taking AIs report AI-associated arthralgia (AIA), leading to therapy abandon in on third of patients, which could lead to cancer recurrence. The purpose of the current study was to evaluate the effectiveness of Neuromuscular Taping (NMT) in the treatment of AIA in women who have been treated of BC. METHODS: This study included 40 BC survivors receiving endocrine therapy (either AIs or TMX) from Hospital Universitario Virgen de la Victoria (Málaga, Spain) suffered from AIA. Patients were randomized to one of the two groups that made this pilot study: A. Placebo intervention B. Real NMT. Clinical data were collected from medical history, grip strength, algometry measured, questionnaires and VAS scale. There have been three interventions prior to the completion of the study, 5 weeks later. The primary objective of this pilot study was to achieve an improvement of pain by 20% decrease of VAS. RESULTS: Significant differences in measures of VAS (p = 0.009), global health status/QoL (p = 0.005), fatigue (p = 0.01) and pain (p = 0.04) were observed post intervention with NMT. CONCLUSIONS: An intervention by NMT to MSCM under treatment with AIs improves their subjective sensation of pain. In addition, this taping had an impact on variables related to the quality of life. This pilot study may be the basis for others to support the use of NMT for the treatment of AIAs, thereby improving their well-being and reducing the dropout rate. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02406794 . Registered on 2 April 2015 Retrospectively registered.

Effects of moderate exercise on biochemical, morphological, and physiological parameters of the pancreas of female mice with estrogen deprivation and dyslipidemia.

Menopausal women are at high risk of developing heart disease. However, physical exercise practice can reverse this scenario. We evaluated the biochemical, morphological, and physiological effects of moderate aerobic physical exercise on the pancreas of knockout mice for LDL receptor with estrogen deprivation by ovariectomy. Animals were divided into six groups (n = 5): sedentary non-ovariectomized control; sedentary ovariectomized control; trained ovariectomized control; sedentary non-ovariectomized LDL-R knockout; sedentary ovariectomized LDL-R knockout; and trained ovariectomized LDL-R knockout. Physical exercise practice promoted improvement in biometric and biochemical parameters analyzed, with reduction of visceral adipose tissue and VLDL, triglycerides, total cholesterol, and blood glucose levels. In addition, physical exercise practice altered the morphology of pancreatic islets and improved their response to the effects of menopause. Thus, physical exercise practice was fundamental to minimize the effects of dyslipidemia associated with ovariectomy in the pancreatic tissue of LDL-R knockout animals, contributing to reduce the risk of developing cardiac diseases in the menopause period.

Obesity accelerates cognitive decline by aggravating mitochondrial dysfunction, insulin resistance and synaptic dysfunction under estrogen-deprived conditions.

Chronic consumption of a high-fat diet (HF) causes peripheral insulin resistance, brain insulin resistance, brain mitochondrial dysfunction and cognitive impairment. Estrogen deprivation has also been found to impair cognition. However, the combined effect of both conditions on the brain is unclear. We hypothesized that estrogen deprivation causes brain insulin resistance, brain mitochondrial dysfunction, hippocampal synaptic dysfunction and cognitive impairment, and that consumption of a HF accelerates these impairments in an estrogen-deprived condition. Seventy-two female rats were divided into sham (S) and ovariectomized (O) groups. Rats in each group were further divided into two subgroups to be fed with either a normal diet (ND) or HF for 4, 8 and 12 weeks. At the end of each period, the Morris water maze test was carried out, after which the blood and brain were collected for metabolic and brain function analysis. Obesity, peripheral insulin resistance, increased brain oxidative stress and hippocampal synaptic dysfunction were observed at the eighth week in the NDO, HFS and HFO rats. However, these impairments were worse in the HFO rats. Interestingly, brain insulin resistance, brain mitochondrial dysfunction and cognitive impairment developed earlier (week eight) in the HFO rats, whereas these conditions were observed later at week 12 in the NDO and HFS rats. Either estrogen deprivation or HF appears to cause peripheral insulin resistance, increased brain oxidative stress, hippocampal synaptic dysfunction, brain mitochondrial dysfunction and brain insulin resistance, which together can lead to cognitive impairment. A HF accelerates and aggravates these deleterious effects under estrogen-deprived conditions.

Menopause-Associated Depression: Impact of Oxidative Stress and Neuroinflammation on the Central Nervous System-A Review.

Perimenopausal depression, occurring shortly before or after menopause, is characterized by symptoms such as emotional depression, anxiety, and stress, often accompanied by endocrine dysfunction, particularly hypogonadism and senescence. Current treatments for perimenopausal depression primarily provide symptomatic relief but often come with undesirable side effects. The development of agents targeting the specific pathologies of perimenopausal depression has been relatively slow. The erratic fluctuations in estrogen and progesterone levels during the perimenopausal stage expose women to the risk of developing perimenopausal-associated depression. These hormonal changes trigger the production of proinflammatory mediators and induce oxidative stress, leading to progressive neuronal damage. This review serves as a comprehensive overview of the underlying mechanisms contributing to perimenopausal depression. It aims to shed light on the complex relationship between perimenopausal hormones, neurotransmitters, brain-derived neurotrophic factors, chronic inflammation, oxidative stress, and perimenopausal depression. By summarizing the intricate interplay between hormonal fluctuations, neurotransmitter activity, brain-derived neurotrophic factors, chronic inflammation, oxidative stress, and perimenopausal depression, this review aims to stimulate further research in this field. The hope is that an increased understanding of these mechanisms will pave the way for the development of more effective therapeutic targets, ultimately reducing the risk of depression during the menopausal stage for the betterment of psychological wellbeing.

Exploratory metabolomic analysis for characterizing the metabolic profile of the urinary bladder under estrogen deprivation.

Background: Estrogen homeostasis is crucial for bladder function, and estrogen deprivation resulting from menopause, ovariectomy or ovarian dysfunction may lead to various bladder dysfunctions. However, the specific mechanisms are not fully understood. Methods: We simulated estrogen deprivation using a rat ovariectomy model and supplemented estrogen through subcutaneous injections. The metabolic characteristics of bladder tissue were analyzed using non-targeted metabolomics, followed by bioinformatics analysis to preliminarily reveal the association between estrogen deprivation and bladder function. Results: We successfully established a rat model with estrogen deprivation and, through multivariate analysis and validation, identified several promising biomarkers represented by 3, 5-tetradecadiencarnitine, lysoPC (15:0), and cortisol. Furthermore, we explored estrogen deprivation-related metabolic changes in the bladder primarily characterized by amino acid metabolism imbalance. Conclusion: This study, for the first time, depicts the metabolic landscape of bladder resulting from estrogen deprivation, providing an important experimental basis for future research on bladder dysfunctions caused by menopause.

Impact of Anti-Estrogen Therapy on Early Cardiovascular Referrals, Tests and Medications in Premenopausal Women with Operable Breast Cancer.

INTRODUCTION: Premenopausal women with high-risk hormone receptor (HR)-positive breast cancer often receive ovarian function suppression (OFS) and anti-estrogen therapy which induces near complete estrogen deprivation (NCED). This treatment improves recurrence-free survival but may increase cardiovascular risk. We sought to identify patterns of cardiovascular care and outcomes in premenopausal women with operable breast cancer. METHODS: Premenopausal women ≤ 50 years of age with stage I-III HR-positive or triple negative breast cancer (TNBC) were identified by retrospective review. We categorized women into 3 groups based on anti-estrogen therapy approach: NCED (HR + OFS), anti-estrogen therapy without OFS (HRnoOFS), and no anti-estrogen therapy (TNBC). Baseline characteristics, post-diagnosis cardiovascular events and cardiovascular actions (tests, referrals and medications) were recorded. Categorical variables were compared among the groups using chi-square and Fisher's exact tests; continuous outcomes were compared using ANOVA. RESULTS: 82, 83, and 52 women were identified in the HR + OFS, HRnoOFS, and TNBC groups respectively; mean follow-up was 5.0 years. Mean number of cardiovascular actions per year were highest in the HR + OFS group compared with HRnoOFS and TNBC groups (0.35 vs. 0.20 and 0.27, respectively; P = .036). The HR + OFS group had significantly more referrals and tests per year than the other groups. Cardiovascular medication initiation did not differ among groups. CONCLUSIONS: In this early follow-up period, there were meaningful numbers of cardiovascular actions, with women on NCED experiencing the most per year. Future work should seek to further understand the impact of anti-estrogen therapy on the cardiovascular health of premenopausal women and test strategies to mitigate cardiotoxicity.

The role of estrogen deprivation therapy in premenopausal women with primary unresectable intracardiac leiomyomatosis: a systematic review and meta-analysis.

BACKGROUND: Intracardiac leiomyomatosis (ICLM) is a rare life-threatening form of intravenous leiomyomatosis (IVLM). The incomplete resection and recurrence are associated with high morbidity and mortality. The objective of this study is to identify that whether estrogen deprivation therapies, including bilateral salpingo-oophorectomy (BSO)-based surgery and gonadotrophin releasing hormone agonists (GnRHa) administration, could bring benefits to patients with primary unresectable ICLM. METHODS: PubMed/MEDLINE (Ovid) was searched (up to May 2021) for studies reporting individual patient data on demographics, clinicopathological features, treatment, and follow-up information. Exclusion criteria were patients who may have been included in two or more publications. This study was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. RESULTS: A total of 114 patients from 70 papers were included. Several reports showed that the tumor in the right atrium and inferior vena cava shrank dramatically after BSO-based surgery, or GnRHa administrated preoperatively in premenopausal women. The rate of complete resection was 64.04% in patients with ICLM, which was 85.25% in no/slight adhesion and no pulmonary nodules group, while 22.22% in firm/extensive adhesion and/or pulmonary nodules group (p < 0.0001). Meanwhile, the recurrence rates in patients with complete resection and incomplete resection were 4.29% and 37.84% respectively (p < 0.0001). Furthermore, complete resection with BSO had the lowest recurrence rate of 3.13%, incomplete resection with BSO had a progression rate of 45.45%, while incomplete resection with ovarian preservation had the highest progression rate of 75.00%. CONCLUSIONS: The recurrence rate of ICLM was closely related to firm/extensive adhesion in IVC or above, and/or pulmonary nodules. BSO-based surgery might reduce the recurrence rate no matter ICLM could be completely resected or not. In addition, estrogen deprivation therapies could decrease tumor burden as a primary treatment, and further make a secondary complete resection feasible in premenopausal women with initially unresectable ICLM.

Enhanced IFNα Signaling Promotes Ligand-Independent Activation of ERα to Promote Aromatase Inhibitor Resistance in Breast Cancer.

Aromatase inhibitors (AIs) reduce estrogen levels up to 98% as the standard practice to treat postmenopausal women with estrogen receptor-positive (ER+) breast cancer. However, approximately 30% of ER+ breast cancers develop resistance to treatment. Enhanced interferon-alpha (IFNα) signaling is upregulated in breast cancers resistant to AIs, which drives expression of a key regulator of survival, interferon-induced transmembrane protein 1 (IFITM1). However, how upregulated IFNα signaling mediates AI resistance is unknown. In this study, we utilized MCF-7:5C cells, a breast cancer cell model of AI resistance, and demonstrate that these cells exhibit enhanced IFNα signaling and ligand-independent activation of the estrogen receptor (ERα). Experiments demonstrated that STAT1, the mediator of intracellular signaling for IFNα, can interact directly with ERα. Notably, inhibition of IFNα signaling significantly reduced ERα protein expression and ER-regulated genes. In addition, loss of ERα suppressed IFITM1 expression, which was associated with cell death. Notably, chromatin immunoprecipitation experiments validated that both ERα and STAT1 associate with ERE sequences in the IFITM1 promoter. Overall, hyperactivation of IFNα signaling enhances ligand-independent activation of ERα, which promotes ER-regulated, and interferon stimulated gene expression to promote survival in AI-resistant breast cancer cells.

The role of inflammation in driving left ventricular remodeling in a pre-HFpEF model.

IMPACT STATEMENT: The incidence of HFpEF continues to increase and ∼2/3 of the patient population are post-menopausal women. Unfortunately, most studies focus on the use of male animal models of remodeling. In this study, however, using female rats to set a model of pre-HFpEF, we provide insights to possible mechanisms that contribute to HFpEF development in humans that will lead us to a better understanding of the underlying pathophysiology of HFpEF.

Jie-Yu Pill, A Proprietary Herbal Medicine, Ameliorates Mood Disorder-Like Behavior and Cognitive Impairment in Estrogen-Deprived Mice Exposed to Chronic Unpredictable Mild Stress: Implication for a Potential Therapy of Menopause Syndrome.

Jie-Yu Pill (JYP) is a proprietary herbal medicine initially developed to treat menstrual mood disorders. This study sought to determine whether JYP could alleviate menopausal psychiatric symptoms in ovariectomized (OVX) mice, an animal model of estrogen deprivation, exposed to chronic unpredictable mild stress (CUMS) and the underlying mechanisms in comparison with estrogen therapy. The OVX+CUMS mice were treated with 0.3 mg/kg estradiol (E2), 2.5 g/kg or 5 g/kg JYP for 36 days, and tested in multiple behavioral paradigms. Serum, uterus, and brain tissues were collected for the measurement of hypothalamus-pituitary-ovarian axis (HPO) and hypothalamus-pituitary-adrenal (HPA) axis hormones, γ-aminobutyric acid (GABA), glutamate, neurotrophins, and estrogen receptors. JYP and E2 had comparable efficacy in reducing anxiety- and depression-like behavior and cognitive impairment of the OVX+CUMS mice. E2 strikingly increased ratio of uterus to body weight of the OVX+CUMS mice, but JYP did not. Both agents suppressed HPO-axis upstream hormones, inhibited HPA-axis hyperactivity by reinstating hypothalamic GABA, restored hippocampal and prefrontal glutamate contents and its receptor expression in the OVX+CUMS mice. While JYP and E2 protected against decreases in hippocampal and prefrontal neurotrophins and estrogen receptors of the OVX+CUMS mice, unlike E2, JYP had no significant effects on these biomarkers in the uterus. These results suggest that JYP has comparable efficacy in ameliorating mood disorder-like behavior and cognitive impairment induced by a combination of estrogen deprivation and chronic stress in association with certain differential uterus-brain mechanisms compared to estrogen therapy. JYP may be a potential therapy for menopause-associated psychiatric disorders.

Effects of estrogen deprivation on memory and expression of related proteins in ovariectomized mice.

BACKGROUND: The ovariectomized (OVX) rodent model is most widely used for studying the influence of estrogen deprivation on memory. However, the results of these studies are inconsistent, in that the memory of OVX rodents shows either impairment or no change. These inconsistent outcomes increase the difficulty of researching neurochemical mechanisms and evaluating drug efficacy. One possible explanation for these discrepancies might be that the time point for memory examination after OVX varies considerably among studies. The aim of our study was to investigate the effects of estrogen deprivation on memory and the expression of memory-related proteins at different times after OVX. METHODS: Novel object recognition (NOR), step-through passive avoidance (STPA) and the Morris water maze (MWM) were performed to evaluate the memory performance of mice at different times after OVX. The expressions of BDNF, TrkB, ULK1 and LC3II/LC3I in the hippocampus were also assessed to explore the relevant mechanisms. RESULTS: After OVX, a significant memory impairment was found in the STPA test at 4 weeks. In the NOR and MWM tests, however, memory deficits were not observed until 8 weeks post-OVX. Interestingly, at 8 weeks, a memory rebound was found in the STPA test. In the hippocampus, the levels of BDNF and TrkB in OVX mice were markedly decreased at 4 and 8 weeks. Subsequently, a significant decrease in the ULK1 and LC3II/LC3I level in OVX mice was observed at 8 weeks. CONCLUSIONS: Memory impairment in mice was observed as early as 4 weeks after OVX, although there was a possibility of memory rebound with the prolongation of estrogen deprivation. Eight weeks of estrogen deprivation would be more likely to induce hippocampus-dependent memory impairment. This progressive impairment of memory might be due to the downregulation of the BDNF/TrkB signaling pathway at the early post-OVX stage, while the decrease of autophagy level in the later stage might also contribute to these progressive alterations. The underlying relationship between the BDNF/TrkB signaling pathway and autophagy in this progressive impairment of memory requires further study.

Loss of Estrogen Efficacy Against Hippocampus Damage in Long-Term OVX Mice Is Related to the Reduction of Hippocampus Local Estrogen Production and Estrogen Receptor Degradation.

Postmenopausal women experience a higher risk for neurodegenerative diseases, including cognitive impairment and ischemic stroke. Many preclinical studies have indicated that estrogen replacement therapy (ERT) may provide protective effects against these neurological diseases. However, the results of Women's Health Initiative (WHI) studies have led to the proposal of "critical period hypothesis," which states that there is a precise window of opportunity for administering beneficial hormone therapy following menopause. However, the underlying molecular mechanisms require further characterization. Here, we explored the effects of ERT on cognition decline and global cerebral ischemia (GCI)-induced hippocampal neuronal damage in mice that had experienced both short-term (ovariectomized (OVX) 1 week) and long-term (OVX 10 weeks) estrogen deprivation. We also further explored the concentration of 17ß-estradiol (E2) in the circulation and hippocampus and the expression of aromatase and estrogen receptors (ERα, ERα-Ser118, and ERß). We found that the neuroprotective effectiveness of ERT against hippocampus damage exhibited in OVX1w mice was totally absent in OVX10w mice. Interestingly, the concentration of hippocampal E2 was irreversibly reduced in OVX10w mice, which was related to the decrease of aromatase expression in the hippocampus. In addition, long-term estrogen deprivation (LTED) led to a decrease in estrogen receptor proteins in the hippocampus. Thus, we concluded that the loss of ERT neuroprotection against hippocampus injury in LTED mice was related to the reduction in hippocampus E2 production and estrogen receptor degradation. These results provide several intervention targets to restore the effectiveness of ERT neuroprotection in elderly post-menopausal women.

Pro-Apoptotic Effects of Estetrol on Long-Term Estrogen-Deprived Breast Cancer Cells and at Low Doses on Hormone-Sensitive Cells.

PURPOSE: Postmenopausal women with estrogen receptor-positive breast cancers often respond initially to tamoxifen or aromatase inhibitor therapy. Resistance to these treatments usually develops within 12 to 18 months. Clinical studies have demonstrated that high-dose estrogen can induce regression of these endocrine-resistant tumors. However, side-effects of high-dose estradiol (E2) or diethylstilbestrol (DES) limit their usage. Estetrol (E4) is the most abundant estrogen during pregnancy and has a long half-life and a low potential for side-effects. Estetrol might then provide benefits similar to DES on tumor regression but with lesser toxicity. METHODS: In this study, we systematically evaluated the effects of E4 on cell proliferation and apoptosis in wild-type MCF-7 and long-term estrogen-deprived (LTED) MCF-7 cells and compared its effects with E2 and estriol (E3). RESULTS: Estetrol induced apoptosis in LTED cells but stimulated growth of MCF-7 cells at concentrations from 10-11 to 10-8 M. These effects of E4 are similar to those of E2 but require much higher doses. Differing from E2, E4 at 10-12 M induced apoptosis in MCF-7 cells and another pregnancy estrogen, E3, acted similarly. No antagonistic effect of E4 or E3 against E2 occurred when they were combined. CONCLUSIONS: The pro-apoptotic effects of E4 and E3 on LTED cells and at low doses on MCF-7 cells indicate that these steroids could be used as therapeutic agents for endocrine-resistant or sensitive breast cancer.

Effects of estrogen and aging on synaptic morphology and distribution of phosphorylated Tyr1472 NR2B in the female rat hippocampus.

Age and estrogens may impact the mobility of N-methyl-D-aspartate receptors (NMDARs) in hippocampal synapses. Here, we used serial section immunogold electron microscopy to examine whether phosphorylated tyrosine 1472 NR2B (pY1472), which is involved in the surface expression of NMDARs, is altered in the dorsal hippocampus of young (3-4 months old) and aged (∼24 months old) ovariectomized rats treated with 17ß-estradiol or vehicle for 2 days. The number of gold particles labeling pY1472 was higher in presynaptic and postsynaptic compartments of aged rats with low estradiol (vehicle-treated) compared to other groups. In terminals, pY1472 levels were elevated in aged rats but reduced by estradiol treatment to levels seen in young rats. Conversely, the mitochondria number was lower in aged females but was restored to young levels by estradiol. In the postsynaptic density and dendritic spines, estradiol reduced pY1472 in young and aged rats. As phosphorylation at Y1472 blocks NR2B endocytosis, reduction of pY1472 by estradiol suggests another mechanism through which estrogen enhances synaptic plasticity by altering localization of NMDAR subunits within synapses.