Estrogen therapy: is time of initiation critical for neuroprotection?

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.

Estrogen receptor beta in astrocytes modulates cognitive function in mid-age female mice

Menopause is associated with cognitive deficits and brain atrophy, but the brain region and cell-specific mechanisms are not fully understood. Here, we identify a sex hormone by age interaction whereby loss of ovarian hormones in female mice at midlife, but not young age, induced hippocampal-dependent cognitive impairment, dorsal hippocampal atrophy, and astrocyte and microglia activation with synaptic loss. Selective deletion of estrogen receptor beta (ERβ) in astrocytes, but not neurons, in gonadally intact female mice induced the same brain effects. RNA sequencing and pathway analyses of gene expression in hippocampal astrocytes from midlife female astrocyte-ERβ conditional knock out (cKO) mice revealed Gluconeogenesis I and Glycolysis I as the most differentially expressed pathways. Enolase 1 gene expression was increased in hippocampi from both astrocyte-ERβ cKO female mice at midlife and from postmenopausal women. Gain of function studies showed that ERβ ligand treatment of midlife female mice reversed dorsal hippocampal neuropathology.

Is Hormone Replacement Therapy a Risk Factor or a Therapeutic Option for Alzheimer's Disease?

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that accounts for more than half of all dementia cases in the elderly. Interestingly, the clinical manifestations of AD disproportionately affect women, comprising two thirds of all AD cases. Although the underlying mechanisms for these sex differences are not fully elucidated, evidence suggests a link between menopause and a higher risk of developing AD, highlighting the critical role of decreased estrogen levels in AD pathogenesis. The focus of this review is to evaluate clinical and observational studies in women, which have investigated the impact of estrogens on cognition or attempted to answer the prevailing question regarding the use of hormone replacement therapy (HRT) as a preventive or therapeutic option for AD. The articles were retrieved through a systematic review of the databases: OVID, SCOPUS, and PubMed (keywords "memory", "dementia," "cognition," "Alzheimer's disease", "estrogen", "estradiol", "hormone therapy" and "hormone replacement therapy" and by searching reference sections from identified studies and review articles). This review presents the relevant literature available on the topic and discusses the mechanisms, effects, and hypotheses that contribute to the conflicting findings of HRT in the prevention and treatment of age-related cognitive deficits and AD. The literature suggests that estrogens have a clear role in modulating dementia risk, with reliable evidence showing that HRT can have both a beneficial and a deleterious effect. Importantly, recommendation for the use of HRT should consider the age of initiation and baseline characteristics, such as genotype and cardiovascular health, as well as the dosage, formulation, and duration of treatment until the risk factors that modulate the effects of HRT can be more thoroughly investigated or progress in the development of alternative treatments can be made.

Role of estrogen in women's Alzheimer's disease risk as modified by APOE

Alzheimer's disease (AD) is characterized by numerous sexual dimorphisms that impact the development, progression, and probably the strategies to prevent and treat the most common form of dementia. In this review, we consider this topic from a female perspective with a specific focus on how women's vulnerability to the disease is affected by the individual and interactive effects of estrogens and apolipoprotein E (APOE) genotype. Importantly, APOE appears to modulate systemic and neural outcomes of both menopause and estrogen-based hormone therapy. In the brain, dementia risk is greater in APOE4 carriers, and the impacts of hormone therapy on cognitive decline and dementia risk vary according to both outcome measure and APOE genotype. Beyond the CNS, estrogen and APOE genotype affect vulnerability to menopause-associated bone loss, dyslipidemia and cardiovascular disease risk. An emerging concept that may link these relationships is the possibility that the effects of APOE in women interact with estrogen status by mechanisms that may include modulation of estrogen responsiveness. This review highlights the need to consider the key AD risk factors of advancing age in a sex-specific manner to optimize development of therapeutic approaches for AD, a view aligned with the principle of personalized medicine.

The X factor in neurodegeneration

Given the aging population, it is important to better understand neurodegeneration in aging healthy people and to address the increasing incidence of neurodegenerative diseases. It is imperative to apply novel strategies to identify neuroprotective therapeutics. The study of sex differences in neurodegeneration can reveal new candidate treatment targets tailored for women and men. Sex chromosome effects on neurodegeneration remain understudied and represent a promising frontier for discovery. Here, we will review sex differences in neurodegeneration, focusing on the study of sex chromosome effects in the context of declining levels of sex hormones during aging.

Randomised controlled trials for the prevention of cognitive decline or dementia: A systematic review

Dementia prevention research has progressed rapidly in recent years, with publication of several large lifestyle intervention trials, and renewed interest in pharmacological interventions, notably for individuals with Alzheimer's disease biomarkers, warranting an updated review of results and methodology. We identified 112 completed trials testing the efficacy of single-domain pharmacological (n = 33, 29%), nutritional (n = 27, 24%), physical activity (n = 18, 16%) and cognitive stimulation (n = 13, 12%), or multidomain (n = 22, 20%) interventions on incident dementia, or a relevant intermediate marker (e.g. cognitive function, biomarkers or dementia risk scores) in people without dementia. The earliest trials tested pharmacological interventions or nutritional supplements, but lifestyle interventions predominated in the last decade. In total, 21 (19%) trials demonstrated a clear beneficial effect on the pre-specified primary outcome (or all co-primary outcomes), but only two (10%) were large-scale (testing blood pressure lowering (Syst-Eur) or multidomain (FINGER) interventions on incident dementia and cognitive change in cognitive function, respectively). Of the 116 ongoing trials, 40% (n = 46) are testing multidomain interventions. Recent methodological shifts concern target populations, primary outcome measures, and intervention design, but study design remains constant (parallel group randomised controlled trial). Future trials may consider using adaptive trials or interventions, and more targeted approaches, since certain interventions may be more effective in certain subgroups of the population, and at specific times in the life-course. Efforts should also be made to increase the representativeness and diversity of prevention trial populations.

Estradiol treatment in young postmenopausal women with self-reported cognitive complaints: Effects on cholinergic-mediated cognitive performance

OBJECTIVE

Older women are at increased risk of developing Alzheimer's disease compared to men. One proposed reason is that following menopause there is a decline in estrogens. Estrogens are important for cholinergic functioning and attenuate the impact of cholinergic antagonists on cognitive performance in postmenopausal women. Self-reported or subjective cognitive complaints in middle or older age may represent a harbinger of cognitive decline and those who endorse cognitive complaints appear more likely to develop future cognitive impairment. However, the response of individuals with cognitive complaints after menopause to estrogen and the relationship to cholinergic functioning has not been investigated. This study investigated the effect of estrogen treatment using 17β-estradiol on cognitive performance following anticholinergic blockade in postmenopausal women and the relationship of this interaction with the level of self-reported (subjective) postmenopausal cognitive complaints.

METHODS

Forty postmenopausal women (aged 50-60 years) completed a 3-month treatment regimen of either 1 mg oral estradiol or placebo. Participants then completed four challenge days in which they completed cognitive and behavioral tasks after one of four cholinergic antagonist drug conditions (oral mecamylamine (MECA), intravenous scopolamine, combined MECA and scopolamine, or PLC).

RESULTS

Compared to PLC, the estradiol treated group performed worse on attention tasks under cholinergic challenge including the choice reaction time task and the critical flicker fusion task. In addition, participants who endorsed greater cognitive complaints showed reduced performance on the N-back working memory task, regardless of whether they received estradiol treatment.

CONCLUSIONS

The findings of this study indicate that estradiol treatment was unable to mitigate anticholinergic blockade in postmenopausal women with subjective cognitive complaints, and worsened performance on attention tasks. Moreover, the present study suggests that greater levels of cognitive complaints following menopause may be associated with an underlying decline in cholinergic function that may manifest as an inability to compensate during working memory tasks.

Menopausal hormone therapy does not improve some domains of memory: A systematic review and meta-analysis

BACKGROUND

Aged women appear to be at a higher risk of developing memory impairment than men. Whether menopausal hormone therapy (MHT) could improve memory in postmenopausal women remains unclear. We thus conducted a meta-analysis to investigate the potential effect of MHT on memory, especially verbal memory, in postmenopausal women.

METHODS

PubMed, Cochrane, Embase, Chinese Biomedical Literature Database, and web of ClinicalTrials.gov were systematically searched for randomized controlled trials comparing MHT versus placebo in postmenopausal women. Our primary outcome of interest is memory function.

RESULTS

We included 10 studies with 2,818 participants in the final analysis. There was no significant differences in immediate recall (weighted mean difference [WMD] 0.34, 95% confidence interval [CI]: -0.73, 1.40), delayed recall (WMD 0.99, 95% CI: -0.51, 2.48), short-delay (WMD -0.00, 95% CI: -0.37, 0.37), and long-delay (WMD -0.19, 95% CI: -0.69, 0.31) recall between WMT and placebo. WMT was associated with a lower digit span forward (mean reduction -0.20, 95% CI: -0.36, -0.03). In women within 5 years of menopause, MHT did not differ in immediate (0.45, 95% CI: -0.75, 1.65) or delayed recall (1.03, 95% CI: -0.93, 3.00), and digit span forward (-0.11, 95% CI: -0.72, 0.50), when compared with placebo.

CONCLUSION

This meta-analysis suggested that MHT had no effect on verbal memory in postmenopausal women, and may impair some domains of short-term memory. Current available evidence does not support MHT for improving memory in women less than 60 years, even in recently menopausal women.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/PROSPERO, identifier CRD42021233255.

Erzhi pills ameliorate cognitive dysfunction and alter proteomic hippocampus profiles induced by d-galactose and Aβ1-40 injection in ovariectomized Alzheimer's disease model rats

CONTEXT

Erzhi pills are a classic Chinese medicine prescription, but their effects on Alzheimer's disease (AD) are not clear.

OBJECTIVE

The protective effects of Erzhi pills in AD rats and their potential mechanisms were investigated.

MATERIALS AND METHODS

An AD rat model was established by ovariectomy combined with d-galactose and Aβ_1-40 injection. Rats were randomly divided into five groups: sham-operated, model, oestradiol valerate (0.80 mg/kg), Erzhi pills high-dose (1.50 g/kg), and Erzhi pills low-dose (0.75 g/kg). Learning and memory abilities were evaluated with the Morris water maze test, oestrogen levels with an ELISA kit, and hippocampal neuron morphology and Nissl bodies in the cytoplasm with H&E and Nissl staining. The expression of ERβ, Aβ_1-40, and p-tau⁴⁰⁴ was determined by immunohistochemistry. Nano LC-LTQ-Orbitrap Proteomics determined potential targets and related signalling pathways. Western blotting was used to detect the expression of the related proteins.

RESULTS

Erzhi pills (1.5, 0.75 g/kg) markedly reduced escape latencies on the MWM, increased numbers of platform crossings, numbers of neurons, Nissl bodies, oestrogen levels (100.18, 43.04 pg/mL), and ERβ-positive cells (57.42, 39.83); Aβ_1-40 (18.85, 36.83)- and p-tau⁴⁰⁴ (14.42, 29.71)-positive cells were significantly decreased. Proteomics identified more than 100 differentially expressed proteins involved in 48 signalling pathways, five of which are involved in the PI3K/Akt signalling pathway. Western blotting showed decreased expression of GSK3β and Bad, while Akt, PI3K, 14-3-3, Bcl-xl, and Bcl-2 were upregulated.

DISCUSSION AND CONCLUSION

Erzhi pills may serve as a potential agent for AD therapeutics by improving learning and memory.

Absolute Quantification of Phosphorylated ERβ Amino Acids in the Hippocampus of Women and in A Rat Model of Menopause

The rapid decline of circulating 17β-estradiol (E2) at menopause leads to negative neurological consequences, although hormone therapy paradoxically has both harmful and positive effects depending on the age at which it is delivered. The inconsistent response to E2 suggests unappreciated regulatory mechanisms for estrogen receptors (ERs), and we predicted it could be due to age-related differences in ERβ phosphorylation. We assessed ERβ phosphorylation using a sensitive mass spectrometry approach that provides absolute quantification (AQUA-MS) of individually phosphorylated residues. Specifically, we quantified phosphorylated ERβ in the hippocampus of women (aged 21-83 years) and in a rat model of menopause at 4 residues with conserved sequence homology between the 2 species: S105, S176, S200, and Y488. Phosphorylation at these sites, which spanned all domains of ERβ, were remarkably consistent between the 2 species, showing high levels of S105 phosphorylation (80%-100%) and low levels of S200 (20%-40%). Further, S200 phosphorylation decreased with aging in humans and loss of E2 in rats. Surprisingly, Y488 phosphorylation, which has been linked to ERβ ligand-independent actions, exhibited approximately 70% phosphorylation, unaltered by species, age, or E2, suggesting ERβ's primary mode of action may not require E2 binding. We further show phosphorylation at 2 sites directly altered ERβ DNA-binding efficiency, and thus could affect its transcription factor activity. These findings provide the first absolute quantification of ERβ phosphorylation in the human and rat brain, novel insights into ERβ regulation, and a critical foundation for providing more targeted therapeutic options for menopause in the future.

Examination of CA1 Hippocampal DNA Methylation as a Mechanism for Closing of Estrogen's Critical Window

There is a critical window for estrogen replacement therapy, beyond which estradiol (E2) fails to enhance cognition and N-methyl-D-aspartate (NMDA) receptor function, and E2-responsive transcription decreases. Much less attention has been given to the mechanism for closing of the critical window, which is thought to involve the decline in estrogen signaling cascades, possibly involving epigenetic mechanisms, including DNA methylation. This study investigated changes in DNA methylation in region CA1 of the hippocampus of ovariectomized female rats over the course of brain aging and in response to E2-treatment, using whole genome bisulfite sequencing. Differential methylation of CpG and non-CpG (CHG and CHH) sites and associated genes were characterized in aged controls (AC), middle-age controls (MC), and young controls (YC) and differential methylation in response to E2-treatment (T) was examined in each age group (AT-AC, MT-MC, and YT-YC). Possible candidate genes for the closing of the critical window were defined as those that were hypomethylated by E2-treatment in younger animals, but were unresponsive in aged animals. Gene ontology categories for possible critical window genes were linked to response to hormones (Adcyap1, Agtr2, Apob, Ahr, Andpro, Calm2, Cyp4a2, Htr1b, Nr3c2, Pitx2, Pth, Pdk4, Slc2a2, Tnc, and Wnt5a), including G-protein receptor signaling (Gpr22 and Rgs4). Other possible critical window genes were linked to glutamate synapses (Nedd4, Grm1, Grm7, and Grin3a). These results suggest that decreased E2 signaling with advanced age, and/or prolonged E2 deprivation, results in methylation of E2-responsive genes, including those involved in rapid E2 signaling, which may limit subsequent transcription.

Menopause and cognitive impairment: A narrative review of current knowledge

A severe impairment of cognitive function characterizes dementia. Mild cognitive impairment represents a transition between normal cognition and dementia. The frequency of cognitive changes is higher in women than in men. Based on this fact, hormonal factors likely contribute to cognitive decline. In this sense, cognitive complaints are more common near menopause, a phase marked by a decrease in hormone levels, especially estrogen. Additionally, a tendency toward worsened cognitive performance has been reported in women during menopause. Vasomotor symptoms (hot flashes, sweating, and dizziness), vaginal dryness, irritability and forgetfulness are common and associated with a progressive decrease in ovarian function and a subsequent reduction in the serum estrogen concentration. Hormone therapy (HT), based on estrogen with or without progestogen, is the treatment of choice to relieve menopausal symptoms. The studies conducted to date have reported conflicting results regarding the effects of HT on cognition. This article reviews the main aspects of menopause and cognition, including the neuroprotective role of estrogen and the relationship between menopausal symptoms and cognitive function. We present and discuss the findings of the central observational and interventional studies on HT and cognition.

Interactions between estradiol, diabetes, and brain aging and the risk for cognitive impairment

The Women's Health Initiative Memory Study reported that older women using conjugated equine estrogens hormone therapy (HT) with or without medroxyprogesterone acetate were at increased risk for probable dementia and smaller brain volumes. These adverse effects were greatest among women who had type 2 diabetes mellitus (T2DM) at baseline or who developed the disease during follow-up. This review summarizes existing literature from randomized trials, observational studies, and preclinical studies to provide a fundamental understanding of the effects of the interaction between T2DM and HT on cognitive and metabolic health changes in brain aging.

Estrogen-dependent hippocampal wiring as a risk factor for age-related dementia in women

Women are more prone than men to develop age-related dementia, such as Alzheimer's disease (AD). This has been linked to the marked decrease in circulating estrogens during menopause. This review proposes to change this perspective and consider women's vulnerability to developing AD as a consequence of sex differences in the neurobiology of memory, focusing on the hippocampus. The hippocampus of cognitively impaired subjects tends to shrink with age; however, in many cases, this can be prevented by exercise or cognitive training, suggesting that if you do not use the hippocampus you lose it. We will review the developmental trajectory of sex steroids-regulated differences on the hippocampus, proposing that the overall shaping action of sex-steroids results in a lower usage of the hippocampus in females, which in turn makes them more vulnerable to the effects of ageing, the "network fragility hypothesis". To explain why women rely less on hippocampus-dependent strategies, we propose a "computational hypothesis" that is based on experimental evidence suggesting that the direct effects of estrogens on hippocampal synaptic and structural plasticity during the estrous-cycle confers instability to the memory-dependent hippocampal network. Finally, we propose to counteract AD with training and/or treatments, such as orienteering, which specifically favour the use of the hippocampus.

Sex effects across the lifespan in women with multiple sclerosis

Multiple sclerosis (MS) is an autoimmune inflammatory demyelinating central nervous system disorder that is more common in women, with onset often during reproductive years. The female:male sex ratio of MS rose in several regions over the last century, suggesting a possible sex by environmental interaction increasing MS risk in women. Since many with MS are in their childbearing years, family planning, including contraceptive and disease-modifying therapy (DMT) counselling, are important aspects of MS care in women. While some DMTs are likely harmful to the developing fetus, others can be used shortly before or until pregnancy is confirmed. Overall, pregnancy decreases risk of MS relapses, whereas relapse risk may increase postpartum, although pregnancy does not appear to be harmful for long-term prognosis of MS. However, ovarian aging may contribute to disability progression in women with MS. Here, we review sex effects across the lifespan in women with MS, including the effect of sex on MS susceptibility, effects of pregnancy on MS disease activity, and management strategies around pregnancy, including risks associated with DMT use before and during pregnancy, and while breastfeeding. We also review reproductive aging and sexual dysfunction in women with MS.

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 17β-estradiol (E2) in the circulation and hippocampus and the expression of aromatase and estrogen receptors (ERα, ERα-Ser118, and ERβ). 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.

Cochlear detoxification: Role of alpha class glutathione transferases in protection against oxidative lipid damage, ototoxicity, and cochlear aging

Age-related hearing loss (AHL) is the most common form of hearing impairment. AHL is thought to be a multifactorial condition resulting from the interaction of numerous causes including aging, genetics, exposure to noise, and exposure to endogenous and exogenous toxins. Cells possess many detoxification enzymes capable of removing thousands of cytotoxic xenobiotics and endogenous toxins such as 4-hydroxynonenal (4-HNE), one of the most abundant cytotoxic end products of lipid peroxidation. The cellular detoxification system involves three phases of enzymatic detoxification. Of these, the glutathione transferase (GST) detoxification system converts a toxic compound into a less toxic form by conjugating the toxic compound to reduced glutathione by GST enzymes. In this review, we describe the current understanding of the cochlear detoxification system and examine the growing link between GST detoxification, oxidative lipid damage, ototoxicity, and cochlear aging with a particular focus on the alpha-class GSTs (GSTAs). We also describe how exposure to ototoxic drugs, exposure to noise, or aging results in increased 4-HNE levels, how 4-HNE damages various cell components under stress conditions, and how GSTAs detoxify 4-HNE in the auditory system.

The Critical Period for Neuroprotection by Estrogen Replacement Therapy and the Potential Underlying Mechanisms

17β-Estradiol (estradiol or E2) is a steroid hormone that has been broadly applied as a neuroprotective therapy for a variety of neurodegenerative and cerebrovascular disorders such as ischemic stroke, Alzheimer's disease, and Parkinson's disease. Several laboratory and clinical studies have reported that Estrogen Replacement Therapy (ERT) had no effect against these diseases in elderly postmenopausal women, and at worst, increased their risk of onset and mortality. This review focuses on the growing body of data from in vitro and animal models characterizing the potential underlying mechanisms and signaling pathways that govern successful neuroprotection by ERT, including the roles of E2 receptors in mediating neuroprotection, E2 genomic regulation of apoptosis- related pathways, membrane-bound receptor-mediated non-genomic signaling pathways, and the antioxidant mechanisms of E2. Also discussed is the current evidence for a critical period of effective treatment with estrogen following natural or surgical menopause and the outcomes of E2 administration within an advantageous time period. The known mechanisms governing the duration of the critical period include depletion of E2 receptors, the switch to a ketogenic metabolic profile by neuronal mitochondria, and a decrease in acetylcholine that accompanies E2 deficiency. Also the major clinical trials and observational studies concerning postmenopausal Hormone Therapy (HT) are summarized to compare their outcomes with respect to neurological disease and discuss their relevance to the critical period hypothesis. Finally, potential controversies and future directions for this field are discussed throughout the review.

G protein-coupled oestrogen receptor stimulation ameliorates iron- and ovariectomy-induced memory impairments through the cAMP/PKA/CREB signalling pathway

Iron accumulation in the brain has been associated with neurodegenerative disorders, and imaging studies in humans indicate that iron content in brain regions correlates with poor performance in cognitive tasks. In rats, iron overload impairs memory retention in a variety of memory tasks. Although the effects of iron on cognition in rodents are extensively reported, no previous study has been conducted in female rats. The incidence of certain dementias, such as Alzheimer's disease, is higher in women after menopause compared to aged-matched men. The role of oestrogen depletion in memory deficits in menopausal women is still a matter of debate. The present study aimed to characterise the effects of iron overload on memory in female rats by investigating the effects of ovariectomy (OVX, an experimental model of oestrogen depletion) in rats submitted to iron overload, as well as examining the effects of G protein-coupled oestrogen receptor (GPER) agonism on memory impairments induced by iron and OVX. Female rats received iron (30 mg kg-1 , orally) or vehicle at postnatal days 12-14 and were submitted to OVX in adulthood. Results showed that either iron or OVX impaired memory for object placement and inhibitory avoidance. The selective GPER agonist G1, administered immediately after training, reversed both iron- and OVX-induced memory impairments. G1 effects were abolished by protein kinase A (PKA) inhibition, suggesting the involvement of the cAMP/PKA/CREB signalling pathway. The search for novel oestrogen agonists with positive effects on cognition may be promising for the development of treatments for memory disorders.

GSTA4 mediates reduction of cisplatin ototoxicity in female mice

Cisplatin is one of the most widely used chemotherapeutic drugs for the treatment of cancer. Unfortunately, one of its major side effects is permanent hearing loss. Here, we show that glutathione transferase α4 (GSTA4), a member of the Phase II detoxifying enzyme superfamily, mediates reduction of cisplatin ototoxicity by removing 4-hydroxynonenal (4-HNE) in the inner ears of female mice. Under cisplatin treatment, loss of Gsta4 results in more profound hearing loss in female mice compared to male mice. Cisplatin stimulates GSTA4 activity in the inner ear of female wild-type, but not male wild-type mice. In female Gsta4^−/− mice, cisplatin treatment results in increased levels of 4-HNE in cochlear neurons compared to male Gsta4^−/− mice. In CBA/CaJ mice, ovariectomy decreases mRNA expression of Gsta4, and the levels of GSTA4 protein in the inner ears. Thus, our findings suggest that GSTA4-dependent detoxification may play a role in estrogen-mediated neuroprotection.

A common complication of cisplatin-based chemotherapy is hearing loss. Here, Park et al. show that glutathione transferase α4 (GSTA4) contributes to reducing cisplatin toxicity in the inner ear of female mice by removing 4-hydroxynonenal (4-HNE).

The Role of Estrogen in Brain and Cognitive Aging

There are 3 common physiological estrogens, of which estradiol (E2) is seen to decline rapidly over the menopausal transition. This decline in E2 has been associated with a number of changes in the brain, including cognitive changes, effects on sleep, and effects on mood. These effects have been demonstrated in both rodent and non-human preclinical models. Furthermore, E2 interactions have been indicated in a number of neuropsychiatric disorders, including Alzheimer's disease, schizophrenia, and depression. In normal brain aging, there are a number of systems that undergo changes and a number of these show interactions with E2, particularly the cholinergic system, the dopaminergic system, and mitochondrial function. E2 treatment has been shown to ameliorate some of the behavioral and morphological changes seen in preclinical models of menopause; however, in clinical populations, the effects of E2 treatment on cognitive changes after menopause are mixed. The future use of sex hormone treatment will likely focus on personalized or precision medicine for the prevention or treatment of cognitive disturbances during aging, with a better understanding of who may benefit from such treatment.

Impact of central and peripheral estrogen treatment on anxiety and depression phenotypes in a mouse model of postmenopausal obesity

Obesity and diabetes increase the risk of depression, and the incidence of these conditions increases rapidly after menopause, but few animal models of postmenopausal obesity have been available. We developed a mouse model of postmenopausal obesity that exhibited anxiety and depressive phenotypes in behavioral tests. To examine the effect of estradiol (E2) in the model, we prepared 4 experimental groups: 1) control, sham-operated female C57BL/6 mice fed a regular diet; 2) OVX-HF, ovariectomized (OVX) mice fed a high-fat diet (HF); 3) E2-SC, OVX-HF mice administered subcutaneous (SC) E2 (50 μg/kg/day); and 4) E2-ICV, OVX-HF mice administered intracerebroventricular (ICV) E2 (1 μg/kg/day). OVX-HF mice exhibited anxiety phenotypes in the open field test, but not in the light-dark box test, and E2 treatment via both routes effectively ameliorated it. OVX-HF mice demonstrated depressive phenotypes in the tail suspension test and forced swim test. Both E2 treatments achieved significant improvement in the tail suspension test, but not in the forced swim test. Serum corticosterone levels did not differ among the groups. Hippocampal expression of glucocorticoid receptor mRNA and serotonin 1A receptor mRNA was significantly increased in OVX-HF mice and was decreased in E2-treated mice. The hypothalamic level of pro-brain-derived neurotrophic factor (proBDNF) protein was tended to decrease in OVX-HF mice, but neither E2 treatment increased it. Since this mouse model exhibited anxiety and depressive phenotypes in relatively short experimental periods without genetic manipulations, it would be useful for further exploring psychiatric phenotypes or screening of therapeutic candidates in postmenopausal obesity.

Cognitive Changes with Reproductive Aging, Perimenopause, and Menopause

This article reviews the role of endogenous estrogen in neural and cognitive processing, followed by an examination of longitudinal cognitive data captured in various stages of the menopausal transition. The remaining text reviews the contradictory results from major hormone therapy trials to date, evidence for the "timing hypothesis," and closes with recommendations for future research and for practicing clinicians.

Rationale and design of a cohort study on primary ovarian insufficiency in female survivors of Hodgkin's lymphoma: influence on long-term adverse effects (SOPHIA)

INTRODUCTION

Hodgkin's lymphoma (HL) has become the prototype of a curable disease. However, many young survivors suffer from late adverse effects of treatment. Both chemotherapy (CT) and radiotherapy (RT) may induce primary ovarian insufficiency (POI), which has been associated with reduced bone mineral density (BMD), neurocognitive dysfunction and possibly cardiovascular disease (CVD). While the general assumption is that POI increases CVD risk, other hypotheses postulate reverse causality, suggesting that cardiovascular risk factors determine menopausal age or that biological ageing underlies both POI and CVD risk. None of these hypotheses are supported by convincing evidence. Furthermore, most studies on POI-associated conditions have been conducted in women with early natural or surgery-induced menopause with short follow-up times. In this study, we will examine the long-term effects of CT-induced and/or RT-induced POI on BMD, cardiovascular status, neurocognitive function and quality of life in female HL survivors.

METHODS AND ANALYSIS

This study will be performed within an existing Dutch cohort of HL survivors. Eligible women were treated for HL at ages 15-39 years in three large hospitals since 1965 and survived for ≥8 years after their diagnosis. Women visiting a survivorship care outpatient clinic will be invited for a neurocognitive, cardiovascular and BMD assessment, and asked to complete several questionnaires and to provide a blood sample. Using multivariable regression analyses, we will compare the outcomes of HL survivors who developed POI with those who did not. Cardiovascular status will also be compared with women with natural POI.

ETHICS AND DISSEMINATION

This study has been approved by the Institutional Review Board of the Netherlands Cancer Institute and has been registered at 'Toetsingonline' from the Dutch Central Committee on Research involving Human Subjects (file no. NL44714.031.13). Results will be disseminated through peer-reviewed publications and will be incorporated in follow-up guidelines for HL survivors.

NAMS 3rd Utian Translational Science Symposium, October 2016, Orlando, Florida A conversation about hormone therapy: is there an appropriate dose, route, and duration of use?

The North American Menopause Society (NAMS) held the 3rd Utian Translational Symposium on October 4, 2016, in Orlando, Florida, to answer questions about the benefits and risks of hormone therapy (HT) for postmenopausal women. This report is a record of the proceedings of that symposium.The maxim about HT for the past 15 years since the publication of the initial results of the Women's Health Initiative (WHI) has been to prescribe the "lowest dose for the shortest period of time." With new clinical trials, observational data, and further analysis of the WHI and the cumulative 13 years' follow-up, it was time to hold a conversation about the state of the evidence and recommendations for HT dose, route, and duration of use.The symposium brought together experts in the field of HT to speak on these topics, organized by session, after which working groups gathered to synthesize the presentations into areas of what still needs to be known and how to proceed with areas of needed research. After the presentations, there was consensus that postmenopausal women aged younger than 60 years or within 10 years of menopause onset without contraindications and who desire to take HT for relief of vasomotor symptoms or prevention of bone loss if at elevated risk can safely do so.The working groups raised the possibility that the use of "Big Data" (pharmacy and cancer databases) would allow answers that cannot be found in clinical trials. This could lead to more appropriate FDA labeling and patient package inserts reflecting the true risks associated with various types and formulations of HT, with differences among estrogen alone, estrogen with a progestogen, and estrogen plus a selective estrogen-receptor modulator for the younger women most likely to initiate these therapies for symptom relief. Differences were found for potential risk among estrogen alone, estrogen with synthetic progestins contrasted to progesterone, lower doses, nonoral doses, and low-dose vaginal estrogen.With all of the available routes and dosages, including vaginal estrogen alone for genitourinary symptoms, there are many options when considering the most appropriate type, dose, formulation, route of administration, and duration of use, taking into account the age of the woman at initiation of HT and the time from menopause.

Cognitive Impacts of Estrogen Treatment in Androgen-Deprived Males: What Needs to be Resolved

Background:

Many prostate cancer (PCa) patients are on androgen deprivation therapy (ADT) as part of their cancer treatments but ADT may lead to cognitive impairments. ADT depletes men of both androgen and estrogen. Whether estradiol supplementation can improve cognitive impairments in patients on ADT is understudied.

Objective:

To summarize data on the effects of estradiol treatment on cognitive function of androgen-deprived genetic male populations (PCa patients and male-to-female transsexuals) and castrated male animals.

Method:

Publications were identified by a literature search on PubMed and Google Scholar.

Results:

While some studies showed that estradiol improves cognitive function (most notably, spatial ability) for castrated rats, what remains uninvestigated are: 1) whether estradiol can improve cognition after long-term androgen deprivation, 2) how estradiol affects memory retention, and 3) how early vs. delayed estradiol treatment after castration influences cognition. For androgen-deprived genetic males, estradiol treatment may improve some cognitive functions (e.g., verbal and visual memory), but the findings are not consistent due to large variability in the study design between studies.

Conclusion:

Future studies are required to determine the best estradiol treatment protocol to maximize cognitive benefits for androgen-deprived genetic males. Tests that assess comparable cognitive domains in human and rodents are needed. What particularly under-investigated is how the effects of estradiol on cognitive ability intersect with other parameters; sleep, depression and physical fatigue. Such studies have clinical implications to improve the quality of life for both PCa patients on ADT as well as for male-to-female transsexuals.

Downregulation of G‑protein‑coupled receptor 30 in the hippocampus attenuates the neuroprotection of estrogen in the critical period hypothesis

The aim of the present study was to investigate the role of G-protein-coupled receptor 30 (GPR30) in long-term 17β-estradiol (E2) deprivation (LTED) in a rat model with global cerebral ischemia (GCI), and its therapeutic target for ischemic stroke in the clinical setting. Following bilateral ovariectomy, GCI was induced in rats 1 or 10 weeks post-surgery. To determine the protein and mRNA expression levels of GPR30 in the hippocampal CA1 region of LTED rats, short-term E2 deprivation (STED) rats and naturally aging rats, western blot analysis and reverse transcription-quantitative polymerase chain reaction were performed. The results of the present study demonstrated that E2 treatment revealed significant neuroprotection post-GCI in STED rats, but not in LTED rats, as well as a decrease in the expression levels of GPR30 in the hippocampal CA1 region. In LTED rats,. Notably, no effects were observed on the ubiquitination of GPR30 following investigation in STED or LTED rats. While the protein and mRNA expression levels of GPR30 were also decreased in the hippocampal CA1 region of female 24-month-old rats compared with 3-month-old rats. E2 treatment initiated for the entire ovariectomy period elevated GPR30 mRNA and protein expression levels, and attenuated the loss of hippocampal neurons in the GCI-induced CA1 region, indicating that E2 treatment exerted robust neuroprotection within LTED rats. However, the neuroprotective effect of E2 may be blocked by G15. The results of the present study revealed that downregulation of GPR30 expression may attenuate the neuroprotection of E2 within LTED conditions in rats post-ovariectomy by leading to neuronal insensitivity to E2 neuroprotection following cerebral ischemia. These results provide evidence that GPR30 may have potential as a novel therapeutic target for the treatment of clinical ischemic stroke.

EFAD transgenic mice as a human APOE relevant preclinical model of Alzheimer's disease

Identified in 1993, APOE4 is the greatest genetic risk factor for sporadic Alzheimer's disease (AD), increasing risk up to 15-fold compared with APOE3, with APOE2 decreasing AD risk. However, the functional effects of APOE4 on AD pathology remain unclear and, in some cases, controversial. In vivo progress to understand how the human (h)-APOE genotypes affect AD pathology has been limited by the lack of a tractable familial AD-transgenic (FAD-Tg) mouse model expressing h-APOE rather than mouse (m)-APOE. The disparity between m- and h-apoE is relevant for virtually every AD-relevant pathway, including amyloid-β (Aβ) deposition and clearance, neuroinflammation, tau pathology, neural plasticity and cerebrovascular deficits. EFAD mice were designed as a temporally useful preclinical FAD-Tg-mouse model expressing the h-APOE genotypes for identifying mechanisms underlying APOE-modulated symptoms of AD pathology. From their first description in 2012, EFAD mice have enabled critical basic and therapeutic research. Here we review insights gleaned from the EFAD mice and summarize future directions.

Sex-Based Differences in the Determinants of Old Age Life Expectancy: The Influence of Perimenopause

Studies using the sensitive periods framework typically examine the effects of early life exposures on later life health, due to the significant growth and development occurring during the first few years of life. The menopausal transition (i.e., perimenopause) is similarly characterized by rapid physiological change, yet rarely has been tested as a sensitive window in adulthood. Cohort mortality data drawn from three historic populations, Sweden (1751-1919), France (1816-1919), and England and Wales (1841-1919), were analyzed using time series methods to assess whether conditions at midlife significantly influenced or "programmed" later life longevity. Results indicated a significant inverse association between mortality at ages 45-49, the average age range in which perimenopause occurred, and life expectancy at age 60 among females in all three countries. Study findings suggest a degree of plasticity associated with women's aging and, in particular, the age group correlated with perimenopause.

Estrogen Signaling as a Therapeutic Target in Neurodevelopmental Disorders

Estrogens, the primary female sex hormones, were originally characterized through their important role in sexual maturation and reproduction. However, recent studies have shown that estrogens play critical roles in a number of brain functions, including cognition, learning and memory, neurodevelopment, and adult neuroplasticity. A number of studies from both clinical as well as preclinical research suggest a protective role of estrogen in neurodevelopmental disorders including autism spectrum disorder (ASD) and schizophrenia. Alterations in the levels of estrogen receptors have been found in subjects with ASD or schizophrenia, and adjunctive estrogen therapy has been shown to be effective in enhancing the treatment of schizophrenia. This review summarizes the findings on the role of estrogen in the pathophysiology of neurodevelopmental disorders with a focus on ASD and schizophrenia. We also discuss the potential of estrogen as a therapeutic target in the above disorders.

Menopausal Hormone Therapy, Age, and Chronic Diseases: Perspectives on Statistical Trends

The release of the Women's Health Initiative (WHI) study in 2002 was a shock to the medical community. Hormone therapy (HT) had generally been considered to be highly beneficial for postmenopausal women since it was the gold standard for relief of menopausal symptoms (hot flashes, night sweats, vaginal atrophy) and it was thought to protect women from osteoporosis, heart disease, and cognitive decline and to generally improve quality of life. However, WHI showed a statistically significant increase in a number of disease states, including breast cancer, cardiovascular disease, and stroke. One problem with the WHI study was that the average age of women in the study was 63, which is considerably older than the age at which most women enter menopause (about 51). The timing hypothesis attempts to rationalize the effect of age on response to HT and risk of various diseases. The data suggests that younger women (50-60) may be protected from heart disease with only a slight increase in breast cancer risk. In contrast, older women (>65) are more susceptible to breast cancer and heart disease and should avoid HT. This Perspective on Statistical Trends evaluates the current data on HT and risk for chronic diseases as a function of age.

Predictive Factors for Verbal Memory Performance Over Decades of Aging: Data from the Women's Healthy Ageing Project

BACKGROUND

Abnormalities in brain structure and function can occur several decades prior to the onset of cognitive decline. It is in the preceding decades that an intervention is most likely to be effective, when informed by an understanding of factors contributing to the disease prodrome. Few studies, however, have sufficient longitudinal data on relevant risks to determine the optimum targets for interventions to improve cognition in aging. In this article we examine the timing and exposure of factors contributing to verbal memory performance in later life.

METHODS

387 participants from the population-based Women's Healthy Ageing Project, mean age at baseline of 49.6 years (range: 45-55 years), had complete neuropsychiatric assessments, clinical information, physical measures, and biomarkers collected at baseline, with at least three follow-up visits that included at least one cognitive reassessment. Mixed linear models were conducted to assess the significance of risk factors on later-life verbal memory. We explored the influence of early, contemporaneous, and cumulative exposures.

RESULTS

Younger age and better education were associated with baseline memory test performance (CERAD). Over the 20 years of study follow-up, cumulative mid- to late-life physical activity had the strongest effect on better later life verbal memory (0.136 [0.058, 0.214]). The next most likely contributors to verbal memory in late life were the negative effect of cumulative hypertension (-0.033 [-0.047, -0.0.18] and the beneficial effect of HDL cholesterol (0.818 [0.042, 1.593]).

CONCLUSIONS

Findings suggest that midlife interventions focused on physical activity, hypertension control, and achieving optimal levels of HDL cholesterol will help maintain later-life verbal memory skills.

Menopause and Parkinson's disease. Interaction between estrogens and brain renin-angiotensin system in dopaminergic degeneration

The neuroprotective effects of menopausal hormonal therapy in Parkinson's disease (PD) have not yet been clarified, and it is controversial whether there is a critical period for neuroprotection. Studies in animal models and clinical and epidemiological studies indicate that estrogens induce dopaminergic neuroprotection. Recent studies suggest that inhibition of the brain renin-angiotensin system (RAS) mediates the effects of estrogens in PD models. In the substantia nigra, ovariectomy induces a decrease in levels of estrogen receptor-α (ER-α) and increases angiotensin activity, NADPH-oxidase activity and expression of neuroinflammatory markers, which are regulated by estrogen replacement therapy. There is a critical period for the neuroprotective effect of estrogen replacement therapy, and local ER-α and RAS play a major role. Astrocytes play a major role in ER-α-induced regulation of local RAS, but neurons and microglia are also involved. Interestingly, treatment with angiotensin receptor antagonists after the critical period induced neuroprotection.

Cognitive effects of estradiol after menopause: A randomized trial of the timing hypothesis

OBJECTIVE

To test the hypothesis that effects of estrogen-containing hormone therapy on cognitive abilities differ between postmenopausal women near to, and further from, menopause.

METHODS

In this randomized, double-blind, placebo-controlled trial, healthy women within 6 years of menopause or 10+ years after menopause were randomly assigned to oral 17β-estradiol 1 mg/d or placebo. Women with a uterus received cyclic micronized progesterone vaginal gel or placebo. The primary outcome assessed at 2.5 and 5 years, compared between treatment groups, was change in a standardized composite of neuropsychological test scores assessing verbal episodic memory. Secondary outcomes assessed executive functions and global cognition.

RESULTS

A total of 567 women were included in modified intention-to-treat analyses after a mean treatment duration of 57 months. For verbal memory, the mean estradiol minus placebo standardized difference in composite scores (-0.06, 95% confidence interval -0.22 to 0.09) was not significant (2-tailed p = 0.33). Differences were similar in early and late postmenopause groups (2-tailed interaction p = 0.88). Interactions between postmenopause groups and differences between treatment groups were not significant for executive functions or global cognition.

CONCLUSIONS

Estradiol initiated within 6 years of menopause does not affect verbal memory, executive functions, or global cognition differently than therapy begun 10+ years after menopause. Estradiol neither benefits nor harms these cognitive abilities regardless of time since menopause.

CLASSIFICATION OF EVIDENCE

This study provides Class I evidence that estradiol initiated within 6 years of menopause does not affect cognition at 2.5 years differently than estradiol initiated 10+ years after menopause.

Methods and baseline cardiovascular data from the Early versus Late Intervention Trial with Estradiol testing the menopausal hormone timing hypothesis

OBJECTIVE

This study aims to present methods and baseline data from the Early versus Late Intervention Trial with Estradiol (ELITE), the only clinical trial designed to specifically test the timing hypothesis of postmenopausal hormone therapy (HT). The timing hypothesis posits that HT effects depend on the temporal initiation of HT relative to time since menopause.

METHODS

ELITE is a randomized, double-blind, placebo-controlled trial with a 2 × 2 factorial design. Six hundred forty-three healthy postmenopausal women without cardiovascular disease were randomized to oral estradiol or placebo for up to 6 to 7 years according to time since menopause (<6 or ≥10 y). Carotid artery intima-media thickness (CIMT) and cardiac computed tomography were conducted to determine HT effects on subclinical atherosclerosis across menopause strata.

RESULTS

Participants in the early and late postmenopausal strata were well-separated by mean age (55.4 vs 65.4 y) and median time since menopause (3.5 vs 14.3 y). Expected risk factors (age, blood pressure, and body mass index) were associated with CIMT at baseline in both strata. In the early postmenopausal group, but not in the late postmenopausal group, we observed significant associations between CIMT and factors that may play a role in the responsiveness of atherosclerosis progression according to timing of HT initiation. These include low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, sex hormone-binding globulin, and serum total estradiol.

CONCLUSIONS

The ELITE randomized controlled trial is timely and unique. Baseline data indicate that ELITE is well-positioned to test the HT timing hypothesis in relation to atherosclerosis progression and coronary artery disease.

Potential Role of Oestrogen Modulation in the Treatment of Neurocognitive Deficits in Schizophrenia

Cognitive deficits are prevalent in schizophrenia, and these deficits represent a disabling aspect of the illness for which there are no current effective treatments. Recent work has shown that sex hormone levels correlate with brain activity and cognitive abilities differentially in patients with schizophrenia relative to healthy control groups. There is emerging evidence suggesting that oestrogen-based therapies may be useful in reversing the cognitive deficits associated with schizophrenia. To date, the results from clinical trials using oestrogen-based therapies to reverse cognitive impairment in schizophrenia have shown that the selective oestrogen receptor modulator raloxifene may be useful to improve attention, memory, learning and the associated brain activity in chronically ill men and women with schizophrenia or schizoaffective disorder. While these findings of cognitive enhancement with a selective oestrogen receptor modulator in people with schizophrenia are encouraging, additional studies will be required to replicate the initial results, assess the time frame of treatment effects, identify biomarkers in subsets of patients who may be more likely to optimally respond to treatment, and identify a more precise mechanism of action, which may include anti-inflammatory effects of oestrogen-based treatments.

Repeated Estradiol Treatment Attenuates Chronic Cerebral Hypoperfusion-Induced Neurodegeneration in Rat Hippocampus

Although a substantial number of pre-clinical and experimental studies have investigated effects of 17β-estradiol, its precise molecular mechanism of action in the early state of chronic cerebral hypoperfusion remains controversial. The present study attempted to verify whether post-ischemic estradiol treatment (33.3 μg/kg for seven consecutive days) affects previously reported number of hippocampal apoptotic cells and amount of DNA fragmentation characteristic for apoptosis as well as the expression of key elements within synaptosomal Akt and Erk signal transduction pathways (NF-κB, Bax, Bcl-2, cytochrome C, caspase 3, and PARP). Additionally, alterations of aforementioned molecules linked to protection in various neurodegenerative disorders were monitored in the cytosolic, mitochondrial, and nuclear fractions associating investigated kinases and NF-κB with gene expression of their downstream effectors-Bcl-2, Bax, and caspase 3. The results revealed that an initial increase in the number of apoptotic cells and amount of DNA fragmentation induced by chronic cerebral hypoperfusion was significantly reduced by 17β-estradiol. In synaptic regions, an altered profile with respect to the protein expression of Bcl-2 and phosphorylated Akt was detected, although the level of other examined proteins was not modified. In other investigated sub-cellular fractions, 17β-estradiol elicited phosphorylation and translocation of Akt and Erk along with modulation of the expression of their subsequent effectors. Our findings support the concept that repeated post-ischemic 17β-estradiol treatment attenuates neurodegeneration induced by chronic cerebral hypoperfusion in hippocampus through the activation of investigated kinases and regulation of their downstream molecules in sub-cellular manner indicating a time window and regime of its administration as a valid therapeutic intervention.

Teneligliptin improves metabolic abnormalities in a mouse model of postmenopausal obesity

A decrease in serum estrogen levels in menopause is closely associated with the development of visceral obesity and the onset of type 2 diabetes in women. In the present study, we demonstrated the therapeutic effects of the novel DPP4 inhibitor, teneligliptin, on the features of postmenopausal obesity in mice. In the control group, female C57BL/6 mice were sham-operated and maintained on a standard diet. In the postmenopausal obese group, ovariectomized (OVX) mice were maintained on a high-fat diet, and were referred to as OVX-HF. In the treated group, teneligliptin at 60 mg/kg per day was administrated to OVX-HF, and were referred to as Tene. After a 12-week food challenge, the metabolic phenotypes of these mice were analyzed. Body weight, fat accumulation, and glucose intolerance were greater in OVX-HF than in control, while these abnormalities were markedly improved without alterations in calorie intake in Tene. Teneligliptin effectively ameliorated the characteristics of metabolic abnormalities associated with postmenopausal obesity. Regarding chronic inflammation in visceral adipose tissue, the numbers of F4/80(+)CD11c(+)CD206(-) M1-macrophages in flow cytometry, crown-like structure formation in immunohistochemistry, and proinflammatory cytokine expression were significantly attenuated in Tene. Hepatic steatosis was also markedly improved. Furthermore, decreased energy consumption in the dark and light phases, reduced locomotor activity in the dark phase, and lowered core body temperature in OVX-HF were ameliorated in Tene. Since obesity and reduced energy metabolism are a common physiology of menopause, teneligliptin appears to be beneficial as a treatment for type 2 diabetes in postmenopausal obesity.

Psychological effects of androgen-deprivation therapy on men with prostate cancer and their partners

The clinical benefits of androgen-deprivation therapy (ADT) for men with prostate cancer (PC) have been well documented and include living free from the symptoms of metastases for longer periods and improved quality of life. However, ADT comes with a host of its own serious side effects. There is considerable evidence of the adverse cardiovascular, metabolic, and musculoskeletal effects of ADT. Far less has been written about the psychological effects of ADT. This review highlights several adverse psychological effects of ADT. The authors provide evidence for the effect of ADT on men's sexual function, their partner, and their sexual relationship. Evidence of increased emotional lability and depressed mood in men who receive ADT is also presented, and the risk of depression in the patient's partner is discussed. The evidence for adverse cognitive effects with ADT is still emerging but suggests that ADT is associated with impairment in multiple cognitive domains. Finally, the available literature is reviewed on interventions to mitigate the psychological effects of ADT. Across the array of adverse effects, physical exercise appears to have the greatest potential to address the psychological effects of ADT both in men who are receiving ADT and in their partners.

Estrogens and cognition: Friends or foes?: An evaluation of the opposing effects of estrogens on learning and memory

This article is part of a Special Issue "Estradiol and cognition". Estrogens are becoming well known for their robust enhancement on cognition particularly for learning and memory that relies upon functioning of the hippocampus and related neural systems. What is also emerging is that estrogen modulation of cognition is not uniform, at times enhancing yet at other times impairing learning. This review explores the bidirectional effects of estrogens on learning from a multiple memory systems view, focusing on the hippocampus and striatum, whereby modulation by estrogens sorts according to task attributes and neural systems engaged during cognition. We highlight our findings showing that the ability to solve hippocampus-sensitive tasks typically improves under relatively high estrogen status while the ability to solve striatum-sensitive tasks degrades with estrogen exposures. Though constrained by dose and timing of exposure, these opposing enhancements and impairments of cognition can be observed following treatments with different estrogenic compounds including the hormone estradiol, the isoflavone genistein found in soybeans, and agonists that are selective for specific estrogen receptors, suggesting that activation of a single receptor type is sufficient to produce the observed shifts in learning strategies. Using this multi-dimensional framework will allow us to extend our thinking of the relationship between estrogens and cognition to other brain regions and cognitive functions.

Utilizing induced pluripotent stem cells (iPSCs) to understand the actions of estrogens in human neurons

This article is part of a Special Issue "Estradiol and Cognition". Over recent years tremendous progress has been made towards understanding the molecular and cellular mechanism by which estrogens exert enhancing effects on cognition, and how they act as a neuroprotective or neurotrophic agent in disease. Currently, much of this work has been carried out in animal models with only a limited number of studies using native human tissue or cells. Recent advances in stem cell technology now make it possible to reprogram somatic cells from humans into induced pluripotent stem cells (iPSCs), which can subsequently be differentiated into neurons of specific lineages. Importantly, the reprogramming of cells allows for the generation of iPSCs that retain the genetic "makeup" of the donor. Therefore, it is possible to generate iPSC-derived neurons from patients diagnosed with specific diseases, that harbor the complex genetic background associated with the disorder. Here, we review the iPSC technology and how it's currently being used to model neural development and neurological diseases. Furthermore, we explore whether this cellular system could be used to understand the role of estrogens in human neurons, and present preliminary data in support of this. We further suggest that the use of iPSC technology offers a novel system to not only further understand estrogens' effects in human cells, but also to investigate the mechanism by which estrogens are beneficial in disease. Developing a greater understanding of these mechanisms in native human cells will also aid in the development of safer and more effective estrogen-based therapeutics.

Long-term consequences of estrogens administered in midlife on female cognitive aging

This article is part of a Special Issue "Estradiol and cognition". Many of the biochemical, structural, and functional changes that occur as the female brain ages are influenced by changes in levels of estrogens. Administration of estrogens begun during a critical window near menopause is hypothesized to prevent or delay age-associated cognitive decline. However, due to potential health risks women often limit use of estrogen therapy to a few years to treat menopausal symptoms. The long-term consequences for the brain of short-term use of estrogens are unknown. Interestingly, there are preliminary data to suggest that short-term use of estrogens during the menopausal transition may afford long-term cognitive benefits to women as they age. Thus, there is the intriguing possibility that short-term estrogen therapy may provide lasting benefits to the brain and cognition. The focus of the current review is an examination of the long-term impact for cognition of midlife use of estrogens. We review data from our lab and others indicating that the ability of midlife estrogens to impact estrogen receptors in the hippocampus may contribute to its ability to exert lasting impacts on cognition in aging females.

Prevention of sporadic Alzheimer's disease: lessons learned from clinical trials and future directions

Interventions that have even quite modest effects at the individual level could drastically reduce the future burden of dementia associated with Alzheimer's disease at the population level. In the past three decades, both pharmacological and lifestyle interventions have been studied for the prevention of cognitive decline or dementia in randomised controlled trials of individuals mostly aged older than 50-55 years with or without risk factors for Alzheimer's disease. Several trials testing the effects of physical activity, cognitive training, or antihypertensive interventions showed some evidence of efficacy on a primary cognitive endpoint. However, most of these trials had short follow-up periods, and further evidence is needed to confirm effectiveness and establish the optimum design or dose of interventions and ideal target populations. Important innovations in ongoing trials include the development of multidomain interventions, and the use of biomarker or genetic inclusion criteria. Challenges include the use of adaptive trial designs, the development of standardised, sensitive outcome measures, and the need for interventions that can be implemented in resource-poor settings.

Object recognition memory deficit and depressive-like behavior caused by chronic ovariectomy can be transitorialy recovered by the acute activation of hippocampal estrogen receptors

It is well known that estradiol (E2) replacement therapy is effective on restoring memory deficits and mood disorders that may occur during natural menopause or after surgical ovarian removal (ovariectomy, OVX). However, it is still unknown the effectiveness of acute and localized E2 administration on the effects of chronic OVX. Here we tested the hypothesis that the intra-hippocampal E2 infusion, as well as specific agonists of estrogen receptors (ERs) alpha (ERα) and beta (ERβ), are able to mend novel object recognition (NOR) memory deficit and depressive-like behavior caused by 12 weeks of OVX. We found that both ERα and ERβ activation, at earlier stages of consolidation, recovered the NOR memory deficit caused by 12 w of OVX. Conversely, only the ERβ activation was effective in decreasing the depressive-like behavior caused by 12 w of OVX. Furthermore, we investigated the effect of OVX on hippocampal volume and ERs expression. The structural MRI showed no alteration in the hippocampus volume of 12 w OVX animals. Interestingly, ERα expression in the hippocampus decreased after one week of OVX, but increased in 12 w OVX animals. Overall, we may conclude that the chronic estrogen deprivation, induced by 12 weeks of OVX, modulates the hippocampal ERα expression and induces NOR memory deficit and depressive-like behaviors. Nonetheless, it is noteworthy that the acute effects of E2 on NOR memory and depressive-like behavior are still apparent even after 12 weeks of OVX.

Estrogen Effects on Cognitive and Synaptic Health Over the Lifecourse

Estrogen facilitates higher cognitive functions by exerting effects on brain regions such as the prefrontal cortex and hippocampus. Estrogen induces spinogenesis and synaptogenesis in these two brain regions and also initiates a complex set of signal transduction pathways via estrogen receptors (ERs). Along with the classical genomic effects mediated by activation of ER α and ER β, there are membrane-bound ER α, ER β, and G protein-coupled estrogen receptor 1 (GPER1) that can mediate rapid nongenomic effects. All key ERs present throughout the body are also present in synapses of the hippocampus and prefrontal cortex. This review summarizes estrogen actions in the brain from the standpoint of their effects on synapse structure and function, noting also the synergistic role of progesterone. We first begin with a review of ER subtypes in the brain and how their abundance and distributions are altered with aging and estrogen loss (e.g., ovariectomy or menopause) in the rodent, monkey, and human brain. As there is much evidence that estrogen loss induced by menopause can exacerbate the effects of aging on cognitive functions, we then review the clinical trials of hormone replacement therapies and their effectiveness on cognitive symptoms experienced by women. Finally, we summarize studies carried out in nonhuman primate models of age- and menopause-related cognitive decline that are highly relevant for developing effective interventions for menopausal women. Together, we highlight a new understanding of how estrogen affects higher cognitive functions and synaptic health that go well beyond its effects on reproduction.

Prolonged androgen deprivation may influence the autoregulation of estrogen receptors in the brain and pelvic floor muscles of male rats

Androgen deprivation in males has detrimental effects on various tissues and bodily functions, some of which can be restored by estradiol (E2) administration. We investigated how the duration of androgen deprivation affects the autoregulation of estrogen receptors (ERs) levels in core brain areas associated with sexual behavior and cognition, as well as in pelvic floor muscles (PFM). We also measured c-Fos levels in brain areas associated with sexual behavior shortly after the rats mated. Prolonged castration increases ERα levels in the preoptic area (POA) and E2 treatment reverses these effects. In the POA, c-Fos levels after mating are not affected by the duration of androgen deprivation and/or E2 treatment. ERβ levels in the POA as well as c-Fos levels in the POA and the core area of nucleus accumbens correlate with the mounting frequency for E2-treated Short-Term castrates. Additionally, ERβ levels in the medial amygdala are positively correlated with the mounting frequency of Long-Term castrates that received E2 treatment. In the hippocampus, ERs are downregulated only when E2 is administered early after castration, whereas downregulation of ERα in the prefrontal cortex only occurs with delayed E2 treatment. Early, but not delayed, E2 treatment after castration increases ERβ levels in the bulbocavernosus and ERα levels in the levator ani of male rats. Our data suggest that the duration of androgen deprivation may influence the autoregulation of ERs by E2 treatment in select brain areas and pelvic floor muscles of male rats.