Effects of hormone therapy on cognition and mood

Therapeutic Effects Of Combined and Chronic Treatment of Tat-GluA23y and D-Serine on Cognitive Dysfunction in Postmenopausal Rats

BACKGROUND

The incidence of Alzheimer's disease (AD) in female gender compared with male has been addressed as a health concern, particularly in menopausal age. We here hypothesized that co-administration of NMDARs agonist (D-serine) and AMPARs endocytosis inhibitor (Tat-GluA23y) might be a potential target for alleviating memory impairment in sporadic Alzheimer model of rats.

METHODS

Forty-eight female Wistar rats weighing 200-220 randomly divided into six groups. One month later, ovariectomized rats underwent stereotaxic surgery and were cannulated into the brain lateral ventricles. Streptozotocin was injected (3 mg/kg), then animals received the related treatments until the day 51, which experienced acquisition of spatial memory in Morris Water Maze test. Finally, the level of phosphorylated cAMP response element binding protein (CREB) in the hippocampus was measured by Western blotting.

RESULTS

Co-administration of D-serine and GluA23y significantly enhanced the acquisition and retrieval of impaired spatial memory in ovariectomized rats with AD (p < .001). Compared to Glu-A 23, D-serine caused more improvement in the mentioned parameters above, however, these values for both groups were still significantly different from the control group (P < .05).

CONCLUSION

Simultaneous treatment with D-serine and GluA23y synergistically improved STZ induced spatial memory impairment in OVX rat, probably partly via increase in phosphorylated CREB protein.

Concurrent high-intensity interval training and probiotic supplementation improve associative memory via increase in insulin sensitivity in ovariectomized rats

OBJECTIVES

Metabolic syndrome (MetS) is a serious concern among postmenopausal women which predisposes them to cardiovascular and cognitive disorders. Healthful diet and exercise training have been essential strategies to prevent the progress of MetS. The aim of this study was to evaluate the effect of supplementation with a native potential probiotic and high-intensity interval training (HIIT) for 8 weeks on retention of associative memory in rats with ovariectomy- induced metabolic syndrome.

METHOD

Thirty-two female ovariectomized Wistar rats were divided into four groups (n = 8/group): Control (OVX + Veh), exercise (OVX + Exe), probiotic (OVX + Pro), exercise with probiotic (OVX + Exe + Pro). One sham surgery group was included as a control group. Animals received 8 weeks interventions, and then were tested in a step through passive avoidance learning and memory paradigm, to assess long term memory. Then serum levels of adiponectin, insulin and glucose were measured by ELISA and colorimetry respectively. Data were analyzed by Kruskal-Wallis, Mann-Whitney and also One-way analysis of variance (ANOVA).

RESULTS

Eight weeks of HIIT and probiotic supplementation caused an increase in step through latency and shortening of total time spent in the dark compartment in OVX + Exe + Pro group compared with OVX + Veh group. Also significant increase in serum adiponectin levels, in parallel with a reduction in glucose, insulin and HOMA-IR were achieved by the group of OVX + Exe + Pro.

CONCLUSION

The present study indicates that HIIT combined with probiotics supplementation for 8 weeks effectively improves associative memory in MetS model of rats partly via improving insulin sensitivity and adiponectin level.

Evaluations of memory, anxiety, and the growth factor IGF-1R after post-surgical menopause treatment with a highly selective progestin

Progestogens are a key component of menopausal hormone therapies. While some progestogens can be detrimental to cognition, there is preclinical evidence that progestogens with a strong progesterone-receptor affinity benefit some molecular mechanisms believed to underlie cognitive function. Thus, a progestin that maximizes progesterone-receptor affinity and minimizes affinities to other receptors may be cognitively beneficial. We evaluated segesterone-acetate (SGA), a 19-norprogesterone derivative with a strong progesterone-receptor affinity and no androgenic or estrogenic-receptor activity, hypothesizing that it would enhance cognition. Middle-aged rats underwent Sham or Ovariectomy (Ovx) surgery followed by administration of medroxyprogesterone-acetate (MPA; used as a positive control as we have previously shown MPA-induced cognitive deficits), SGA (low or high dose), or vehicle (one Sham and one Ovx group). Spatial working and reference memory, delayed retention, and anxiety-like behavior were assessed, as were memory- and hormone- related protein assays within the frontal cortex, dorsal hippocampus, and entorhinal cortex. Low-dose SGA impaired spatial working memory, while high-dose SGA had a more extensive detrimental impact, negatively affecting spatial reference memory and delayed retention. Replicating previous findings, MPA impaired spatial reference memory and delayed retention. SGA, but not MPA, alleviated Ovx-induced anxiety-like behaviors. On two working memory measures, IGF-1R expression correlated with better working memory only in rats without hormone manipulation; any hormone manipulation or combination of hormone manipulations used herein altered this relationship. These findings suggest that SGA impairs spatial cognition after surgical menopause, and that surgical menopause with or without progestin administration disrupts relationships between a growth factor critical to neuroplasticity.

Hormone-sleep interactions predict cerebellar connectivity and behavior in aging females

Sex hormones fluctuate over the course of the female lifespan and are associated with brain health and cognition. Thus, hormonal changes throughout female adulthood, and with menopause in particular, may contribute to sex differences in brain function and behavior. Further, sex hormones have been correlated with sleep patterns, which also exhibit sex-specific impacts on the brain and behavior. As such, the interplay between hormones and sleep may contribute to late-life brain and behavioral outcomes in females. Here, in a sample of healthy adult females (n = 79, ages 35-86), we evaluated the effect of hormone-sleep interactions on cognitive and motor performance as well as cerebellar-frontal network connectivity. Salivary samples were used to measure 17β-estradiol, progesterone, and testosterone levels while overnight actigraphy was used to quantify sleep patterns. Cognitive behavior was quantified using the composite average of standardized scores on memory, processing speed, and attentional tasks, and motor behavior was indexed with sequence learning, balance, and dexterity tasks. We analyzed resting-state connectivity correlations for two specific cerebellar-frontal networks: a Crus I to dorsolateral prefrontal cortex network and a Lobule V to primary motor cortex network. In sum, results indicate that sex hormones and sleep patterns interact to predict cerebellar-frontal connectivity and behavior in aging females. Together, the current findings further highlight the potential consequences of endocrine aging in females and suggest that the link between sex hormones and sleep patterns may contribute, in part, to divergent outcomes between sexes in advanced age.

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.

Associations Between Midlife Menopausal Hormone Therapy Use, Incident Diabetes, and Late Life Memory in the Wisconsin Longitudinal Study

BACKGROUND

Prior research suggests a link between menopausal hormone therapy (MHT) use, memory function, and diabetes risk. The menopausal transition is a modifiable period to enhance long-term health and cognitive outcomes, although studies have been limited by short follow-up periods precluding a solid understanding of the lasting effects of MHT use on cognition.

OBJECTIVE

We examined the effects of midlife MHT use on subsequent diabetes incidence and late life memory performance in a large, same-aged, population-based cohort. We hypothesized that the beneficial effects of MHT use on late life cognition would be partially mediated by reduced diabetes risk.

METHODS

1,792 women from the Wisconsin Longitudinal Study (WLS) were included in analysis. We employed hierarchical linear regression, Cox regression, and causal mediation models to test the associations between MHT history, diabetes incidence, and late life cognitive performance.

RESULTS

1,088/1,792 women (60.7%) reported a history of midlife MHT use and 220/1,792 (12.3%) reported a history of diabetes. MHT use history was associated with better late life immediate recall (but not delayed recall), as well as a reduced risk of diabetes with protracted time to onset. Causal mediation models suggest that the beneficial effect of midlife MHT use on late life immediate recall were at least partially mediated by diabetes risk.

CONCLUSION

Our data support a beneficial effect of MHT use on late life immediate recall (learning) that was partially mediated by protection against diabetes risk, supporting MHT use in midlife as protective against late life cognitive decline and adverse health outcomes.

Association of Hormone Therapy With Depression During Menopause in a Cohort of Danish Women

IMPORTANCE

During menopause, the levels of estrogen and progesterone decrease and 60% to 70% of women experience menopausal symptoms, including mood disturbances. The latter might be prevented by hormone therapy (HT), yet some studies have suggested that use of HT might be associated with increased risk of depression.

OBJECTIVE

To examine whether use of HT during menopause was associated with a subsequent diagnosis of depression.

DESIGN, SETTING, AND PARTICIPANTS

This nationwide register-based cohort and self-controlled case series study included all women in Denmark aged 45 years between January 1, 1995, through December 31, 2017 (n = 825 238), without prior oophorectomy, breast cancer, or cancer in reproductive organs. Follow-up was completed on December 31, 2018. The statistical analysis was performed from September 1, 2021, through May 31, 2022.

EXPOSURES

Redeemed prescriptions of different types of HT identified by the Anatomical Therapeutic Chemical classification system codes (G03C [estrogen] and G03F [estrogen combined with progestin]) in the Danish National Prescription Registry between 1995 and 2017. Type of administration was divided into systemic (oral or transdermal) and local (intravaginal or intrauterine).

MAIN OUTCOMES AND MEASURES

A hospital diagnosis of depression (International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, codes F32-F33 and International Classification of Diseases, Eighth Revision, codes 296.09, 296.29, 298.0, and 300.49) between 1995 through 2018. Associations were examined in cohort and self-controlled case series analysis using Cox proportional hazards and fixed-effects Poisson regression models.

RESULTS

During follow-up from 45 years of age to a mean of 56.0 (range, 45.1-67.7) years, 189 821 women (23.0%) initiated systemically or locally administered HT and 13 069 (1.6%) were diagnosed with depression. Systemically administered HT was mainly initiated before 50 years of age and was associated with a higher risk of a subsequent depression diagnosis (hazard ratio [HR] for 48-50 years of age, 1.50 [95% CI, 1.24-1.81]). The risk was especially elevated the year after initiation of both treatment with estrogen alone (HR, 2.03 [95% CI, 1.21-3.41]) and estrogen combined with progestin (HR, 2.01 [95% CI,1.26-3.21]). Locally administered HT was initiated across all ages and was not associated with depression risk (HR, 1.15 [95% CI, 0.70-1.87]). It was, however, associated with a lower risk of depression when initiated after 54 years of age (HR for 54-60 years of age, 0.80 [95% CI, 0.70-0.91]). In self-controlled analysis, which efficiently accounts for time-invariant confounding, users of systemically administered HT had higher rates of depression in the years after initiation compared with the years before treatment (incidence rate ratio for 0-1 year after initiation, 1.66 [95% CI, 1.30-2.14]).

CONCLUSIONS AND RELEVANCE

These findings suggest that systemically administered HT before and during menopause is associated with higher risk of depression, especially in the years immediately after initiation, whereas locally administered HT is associated with lower risk of depression for women 54 years or older.

What is there to know about the effects of progestins on the human brain and cognition?

Progestins are an important component of hormonal contraceptives (HCs) and hormone replacement therapies (HRTs). Despite an increasing number of studies elucidating the effects of HCs and HRTs, little is known about the effects of different types of progestins included in these medications on the brain. Animal studies suggest that various progestins interact differently with sex steroid, mineralocorticoid and glucocorticoid receptors and have specific modulatory effects on neurotransmitter systems and on the expression of neuropeptides, suggesting differential impacts on cognition and behavior. This review focuses on the currently available knowledge from human behavioral and neuroimaging studies pooled with evidence from animal research regarding the effects of progestins on the brain. The reviewed information is highly relevant for improving women's mental health and making informed choices regarding specific types of contraception or treatment.

The association of reproductive stage with lobular cerebellar network connectivity across female adulthood

Sex-specific differences in the aging cerebellum may be related to hormone changes with menopause. We evaluated the association between reproductive stage and lobular cerebellar network connectivity using data from the Cambridge Centre for Ageing and Neuroscience repository. We used raw structural and resting state neuroimaging data and information regarding age, sex, and menopause-related variables. Crus I and II and Lobules V and VI were our cerebellar seeds of interest. We characterized reproductive stage using the Stages of Reproductive Aging Workshop criteria. Results show that postmenopausal females have lower cerebello-striatal and cerebello-cortical connectivity, particularly in frontal regions, along with lower connectivity within the cerebellum, compared to reproductive females. Postmenopausal females also exhibit greater connectivity in some brain areas as well. Differences begin to emerge across transitional stages of menopause. Further, results reveal sex-specific differences in connectivity between female reproductive groups and age-matched male control groups. This suggests that menopause may be associated with cerebellar network connectivity in aging females, and sex differences in the aging brain may be related to this biological process.

Long-Term Gender-Affirming Hormone Therapy and Cognitive Functioning in Older Transgender Women Compared With Cisgender Women and Men

BACKGROUND

Long-term gender-affirming hormone therapy (GHT) in older transgender individuals could have beneficial effects on cognitive functioning. Cardiovascular risk factors and psychological factors are known determinants of cognition. Despite the rising number of older transgender individuals, only few studies have examined cognitive functioning in this population.

AIM

We aimed to assess differences in cognitive functioning between transgender women, and non-transgender (cisgender) women and men, and investigated the contribution of cardiovascular risk factors and psychological factors on these differences.

METHODS

In this study, 37 transgender women (age range 55 to 69) receiving GHT for at least ten years (range 10.2 to 41.6) were examined, and their cognitive functioning was compared to an age and education level matched cohort consisting of 222 cisgender women and men from the Longitudinal Aging Study Amsterdam. Linear regression analyses were performed.

OUTCOMES

Cognitive functioning was assessed by neuropsychological tests including Mini-Mental State Examination (MMSE), Category Fluency animals, Letter Fluency D, 15-Word test (15WT) immediate and delayed recall. Additionally, cardiovascular risk factors and psychological factors such as cardiovascular disease, hypertension, antihypertensive use, statin use, diabetes mellitus, overweight, smoking, alcohol consumption, psychopharmaceutical use, anxiety and depression symptoms were collected.

RESULTS

Transgender women had higher MMSE scores compared with cisgender women (+0.9, 95% CI 0.4 to 1.5), and cisgender men (+1.1, 95% CI 0.4 to 1.8). On all other tests transgender women performed similar to cisgender men. Transgender women performed at a lower level than cisgender women on 15WT immediate recall, -5.5, 95% CI -7.6 to -3.4, and 15WT delayed recall, -2.7, 95% CI -3.7 to -1.7, and equal to cisgender women on Fluency animals and Fluency D. Cardiovascular and psychological factors (i.e., cardiovascular disease and depression symptoms) partly explained differences on MMSE score between transgender women and cisgender-control groups.

CLINICAL IMPLICATIONS

The results of this study do not indicate a need for tailored hormone treatment strategies for older transgender women, based on cognitive aspects after long-term GHT.

STRENGTHS & LIMITATIONS

As one of the first studies, this study compared older transgender women to a large cohort of cisgender men and women regarding cognitive functioning and took into account numerous potential influencing factors. Limitations include difference in test procedures and the cross-sectional design of the study.

CONCLUSION

Cognitive differences between transgender women and cisgender women and men were small, albeit significant. This may suggest that long-term GHT effects on cognitive functioning in older transgender women are minimal. van Heesewijk JO, Dreijerink KMA, Wiepjes CM, et al. Long-Term Gender-Affirming Hormone Therapy and Cognitive Functioning in Older Transgender Women Compared With Cisgender Women and Men. J Sex Med 2021;18:1434-1443.

Estradiol selectively regulates metabolic substrates across memory systems in models of menopause

Estrogen loss at menopause is thought to contribute to specific memory problems commonly encountered by women who are transitioning through or who have experienced menopause. Work in preclinical models suggests that estrogens bidirectionally regulate cognition through direct actions on different neural systems called memory systems, enhancing some types of learning and memory while impairing others. The energy load in the brain during cognitive activity is notoriously high, requiring sufficient provisions of metabolic substrates such as glucose, lactate, or ketones for optimal cognition. Thus, it is possible that estrogens bidirectionally regulate energy substrate availability within each system to produce the improvements and impairments in learning and memory. Indeed, estradiol increases extracellular levels of glucose in the hippocampus, a shift that corresponds to the hormone's beneficial effects on hippocampus-sensitive cognition. In contrast, estradiol decreases levels of lactate and ketones in the striatum, a shift that corresponds to the impairing effects of estradiol on striatum-sensitive cognition. Menopause may thus be associated with both cognitive improvements and impairments depending on estradiol status and on the problem to be solved. We propose that regulation of neural metabolism is one likely mechanism for these bidirectional effects of estradiol on cognition.

Epigenetic prediction of 17β-estradiol and relationship to trauma-related outcomes in women

17β-estradiol (E2) levels in women correlate with multiple neuropsychiatric symptoms, including those that are stress-related. Furthermore, prior work from our group has demonstrated that E2 status influences DNA methylation (DNAm) across the genome. We developed and validated a DNAm-based predictor of E2 (one of four naturally occurring estrogens) using a training set of 183 females and a test set of 79 females from the same traumatized cohort. We showed that predicted E2 levels were highly correlated with measured E2 concentrations in our testing set (r ​= ​0.75, p ​= ​1.8e-15). We further demonstrated that predicted E2 concentrations, in combination with measured values, negatively correlated with current post-traumatic stress disorder (PTSD) (β ​= ​−0.38, p ​= ​0.01) and major depressive disorder (MDD) diagnoses (β ​= ​−0.45, p ​= ​0.02), as well as a continuous measure of PTSD symptom severity (β ​= ​−2.3, p ​= ​0.007) in females. Finally, we tested our predictor in an independent data set (n ​= ​85) also comprised of recently traumatized female subjects to determine if the predictor would generalize to a different population than the one on which it was developed. We found that the correlation between predicted and actual E2 concentrations in the external validation data set was also high (r ​= ​0.48, p ​= ​3.0e-6). While further validation is warranted, a DNAm predictor of E2 concentrations will advance our understanding of hormone-epigenetic interactions. Furthermore, such a DNAm predictor may serve as an epigenetic proxy for E2 concentrations and thus provide an important biomarker to better evaluate the contribution of E2 to current and potentially future psychiatric symptoms in samples for which E2 is not measured.

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Neuropsychiatric symptoms correlate with estradiol (E2) levels in females.

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We developed a DNA methylation-based E2 predictor using machine learning approach.

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Our predictor performed well in an external validation cohort of traumatized women.

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Predicted E2 concentrations correlated with stress-related phenotypes.

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Our model may serve as an epigenetic biomarker of E2 status in women.

Estrogen, brain structure, and cognition in postmenopausal women

Declining estrogen levels before, during, and after menopause can affect memory and risk for Alzheimer's disease. Undesirable side effects of hormone variations emphasize a role for hormone therapy (HT) where possible benefits include a delay in the onset of dementia-yet findings are inconsistent. Effects of HT may be mediated by estrogen receptors found throughout the brain. Effects may also depend on lifestyle factors, timing of use, and genetic risk. We studied the impact of self-reported HT use on brain volume in 562 elderly women (71-94 years) with mixed cognitive status while adjusting for aforementioned factors. Covariate-adjusted voxelwise linear regression analyses using a model with 16 predictors showed HT use as positively associated with regional brain volumes, regardless of cognitive status. Examinations of other factors related to menopause, oophorectomy and hysterectomy status independently yielded positive effects on brain volume when added to our model. One interaction term, HTxBMI, out of several examined, revealed significant negative association with overall brain volume, suggesting a greater reduction in brain volume than BMI alone. Our main findings relating HT to regional brain volume were as hypothesized, but some exploratory analyses were not in line with existing hypotheses. Studies suggest lower levels of estrogen resulting from oophorectomy and hysterectomy affect brain volume negatively, and the addition of HT modifies the relation between BMI and brain volume positively. Effects of HT may depend on the age range assessed, motivating studies with a wider age range as well as a randomized design.

The Role of Estrogen Receptors and Their Signaling across Psychiatric Disorders

Increasing evidence suggests estrogen and estrogen signaling pathway disturbances across psychiatric disorders. Estrogens are not only crucial in sexual maturation and reproduction but are also highly involved in a wide range of brain functions, such as cognition, memory, neurodevelopment, and neuroplasticity. To add more, the recent findings of its neuroprotective and anti-inflammatory effects have grown interested in investigating its potential therapeutic use to psychiatric disorders. In this review, we analyze the emerging literature on estrogen receptors and psychiatric disorders in cellular, preclinical, and clinical studies. Specifically, we discuss the contribution of estrogen receptor and estrogen signaling to cognition and neuroprotection via mediating multiple neural systems, such as dopaminergic, serotonergic, and glutamatergic systems. Then, we assess their disruptions and their potential implications for pathophysiologies in psychiatric disorders. Further, in this review, current treatment strategies involving estrogen and estrogen signaling are evaluated to suggest a future direction in identifying novel treatment strategies in psychiatric disorders.

Associations between estradiol and testosterone and depressive symptom scores of the Patient Health Questionnaire-9 in ovariectomized women: a population-based analysis of NHANES data

BACKGROUND

Women are well known to be susceptible to developing affective disorders, yet little attention has been given to effects of ovariectomy-reduced hormones and links with depression. This population-based cross-sectional study aimed to investigate possible associations between ovariectomy-reduced hormones and depression symptom scores of the Patient Health Questionnaire-9 (PHQ-9) in ovariectomized women.

METHODS

Data of PHQ-9 scores, demographics and comorbidities of ovariectomized women were extracted from the U.S. National Health and Nutrition Examination Survey (NHANES) database (2013-2016) and were analyzed retrospectively.

RESULTS

Among ovariectomized women in the NHANES database, serum estradiol levels were significantly positively associated with PHQ-9 scores (ß = 0.014, 95% CI: 0.001, 0.028, P = 0.040), whereas serum testosterone was negatively associated with PHQ-9 scores (ß = -0.033, 95% CI: - 0.048, - 0.018, P < 0.001) after adjusting for confounders. Further stratified analyses revealed that serum estradiol was positively associated with PHQ-9 only among women with history of estrogen use. Serum testosterone levels were negatively associated with PHQ-9 among women with or without prior estrogen use but this was only observed among women aged <  = 60 years (ß = - 0.057, - 0.076, - 0.038, P < 0.001).

CONCLUSIONS

Serum estradiol and testosterone are associated with PHQ-9 scores indicative for depression in ovariectomized women. The associations are modified by age and history of estrogen use. Future prospective studies are warranted to confirm these findings, carefully addressing possible confounding of age-related dementia.

Depression during perimenopause: the role of the obstetrician-gynecologist

Depression in women is more common during perimenopause (the transition to menopause) than at other times in the life cycle. Symptoms of depression may be different in perimenopausal women compared to younger or older women, and are often dismissed as part of normal menopause. This is an expert narrative review. There are several evidence-based screening modalities which can be integrated into routine women's health visits, and can facilitate distinguishing between depression and normal perimenopausal symptoms. There is emerging evidence regarding the effect of hormonal changes on the development of perimenopausal depression and its optimal treatment, though critical research gaps remain. Obstetrician-gynecologists and other primary care providers play a vital role in the detection and management of depression in women. Providers caring for women during perimenopause have a unique opportunity to diagnose depression in their patients and identify appropriate treatment options.

Postmenopausal hormone treatment alters neural pathways but does not improve verbal cognitive function

OBJECTIVE

Cognitive outcomes in trials of postmenopausal hormone treatment have been inconsistent. Differing outcomes may be attributed to hormone formulation, treatment duration and timing, and differential cognitive domain effects. We previously demonstrated treatment benefits on visual cognitive function. In the present study, we describe the effects of hormone treatment on verbal outcomes in the same women, seeking to understand the effects of prior versus current hormone treatment on verbal function.

METHODS

This is a cross-sectional evaluation of 57 women (38 hormone users [25 prior long-term users and 13 current users] and 19 never-users). Hormone users took identical formulations of estrogen or estrogen + progestin (0.625 mg/d conjugated equine estrogens with or without medroxyprogesterone acetate) for at least 10 years, beginning within 2 years of menopause. Women were evaluated with tests of verbal function and functional magnetic resonance imaging (fMRI) of a verbal discrimination task.

RESULTS

All women scored similarly on assessments of verbal function (Hopkins Verbal Learning Test and a verbal discrimination task performed during the fMRI scanning session); however, women ever treated with hormones had more left inferior frontal (T = 3.72; P < 0.001) and right prefrontal cortex (T = 3.53; P < 0.001) activation during the verbal task. Hormone-treated women performed slightly worse on the verbal discrimination task (mean accuracy 81.72 ± 11.57 ever-treated, 85.30 ± 5.87 never-treated, P = 0.14), took longer to respond (mean reaction time 1.10 ± 0.17 s ever-treated, 1.02 ± 0.11 never-treated, P = 0.03), and remembered fewer previously viewed words (mean accuracy 62.21 ± 8.73 ever-treated, 65.45 ± 7.49 never-treated, P = 0.18). Increased posterior cingulate activity was associated with longer response times (R = 0.323, P = 0.015) and worse delayed verbal recall (R = -0.328, P = 0.048), suggesting that increased activation was associated with less efficient cognitive processing. We did not detect between group differences in activation in the left prefrontal cortex, superior frontal cortex, thalamus, or occipital/parietal junction.

CONCLUSIONS

Although current and past hormone treatment was associated with differences in neural pathways used during verbal discrimination, verbal function was not higher than never-users.

Role of Estradiol in the Expression of Genes Involved in Serotonin Neurotransmission: Implications for Female Depression

BACKGROUND

In women, changes in estrogen levels may increase the incidence and/or symptomatology of depression and affect the response to antidepressant treatments. Estrogen therapy in females may provide some mood benefits as a single treatment or might augment clinical response to antidepressants that inhibit serotonin reuptake.

OBJECTIVE

We analyzed the mechanisms of estradiol action involved in the regulation of gene expression that modulates serotonin neurotransmission implicated in depression.

METHOD

Publications were identified by a literature search on PubMed.

RESULTS

The participation of estradiol in depression may include regulation of the expression of tryptophan hydroxylase-2, monoamine oxidase A and B, serotonin transporter and serotonin-1A receptor. This effect is mediated by estradiol binding to intracellular estrogen receptor that interacts with estrogen response elements in the promoter sequences of tryptophan hydroxylase-2, serotonin transporter and monoamine oxidase-B. In addition to directly binding deoxyribonucleic acid, estrogen receptor can tether to other transcription factors, including activator protein 1, specificity protein 1, CCAAT/enhancer binding protein β and nuclear factor kappa B to regulate gene promoters that lack estrogen response elements, such as monoamine oxidase-A and serotonin 1A receptor.

CONCLUSION

Estradiol increases tryptophan hydroxylase-2 and serotonin transporter expression and decreases the expression of serotonin 1A receptor and monoamine oxidase A and B through the interaction with its intracellular receptors. The understanding of molecular mechanisms of estradiol regulation on the protein expression that modulates serotonin neurotransmission will be helpful for the development of new and more effective treatment for women with depression.

Estrogen-Dependent Functional Spine Dynamics in Neocortical Pyramidal Neurons of the Mouse

Surgical ovariectomy has been shown to reduce spine density in hippocampal CA1 pyramidal cells of rodents, and this reduction is reversed by 17β-estradiol (E2) treatment in a model of human estrogen replacement therapy. Here, we report reduction of spine density in apical dendrites of layer 5 pyramidal neurons of several neocortical regions that is reversed by subsequent E2 treatment in ovariectomized (OVX) female Thy1M-EGFP mice. We also found that OVX-associated reduction of spine density in somatosensory cortex was accompanied by a reduction in miniature EPSC (mEPSC) frequency (but not mIPSC frequency), indicating a change in functional synapses. OVX-associated spine loss in somatosensory cortex was also rescued by an agonist of the G-protein-linked estrogen receptor (GPER) but not by agonists of the classic estrogen receptors ERα/ERβ, whereas the opposite selectivity was found in area CA1. Acute treatment of neocortical slices with E2 also rescued the OVX-associated reduction in mEPSC frequency, which could be mimicked by a GPER agonist and abolished by a GPER antagonist. Time-lapse in vivo two-photon imaging showed that OVX-associated reduction in spine density is achieved by both an increase in spine loss rate and a decrease in spine gain rate and that subsequent rescue by E2 reversed both of these processes. Crucially, the spines added after E2 rescue were no more likely to reappear at or nearby the sites of pre-OVX spines than those in control mice treated with vehicle. Thus, a model of estrogen replacement therapy, although restoring spine density and dynamics, does not entirely restore functional connectivity.SIGNIFICANCE STATEMENT Estrogen replacement therapy following menopause or surgical removal of the ovaries is a widespread medical practice, yet little is known about the consequences of such treatment for cells in the brain. Here, we show that estrogen replacement reverses some of the effects of surgical removal of the ovaries on the structure and function of brain cells in the mouse. Yet, importantly, the fine wiring of the brain is not returned to the presurgery state by estrogen treatment, suggesting lasting functional consequences.

The effect of hormone replacement therapy on cognitive function in postmenopausal women: An RCT

Background

During the reproductive age, the human brain becomes a target for gonadal steroid hormones. Estrogens influence neural function through effects on neurons and affects indirectly the oxidative stress, inflammation, the cerebral vascular and the immune system.

Objective

To evaluate the effect of the traditional hormone replacement therapy (HRT) on the cognitive function in postmenopausal women.

Materials and Methods

In this randomized clinical trial, 140 postmenopausal women, from November 2014 to February 2015, were included. Women were randomly divided into two groups. Each woman in the case group took traditional HRT (0.625mg conjugated equine estrogens+2.5mg medroxyprogesterone acetate daily) plus one Cal+D tablet (500 mg calcium+200 IU vitamin D) daily for four months. Women in the control group received only one Cal+D tablet (500 mg calcium+200 IU vitamin D) daily for four months period. The Montreal Cognitive Assessment (MoCA) and Green Climacteric Scale (GCS) questionnaires filled out after the intervention and compared between the two groups.

Results

The mean points of the MoCA after the intervention indicate that all MoCA domains except for the orientation improved in the case group. There was a significant difference in the memory domain after the treatment between the two groups. MoCA domains and GCS were negatively correlated after the intervention (r=-0.235,p=0.006).

Conclusion

The HRT has affected some of the MoCA factors. The effects of HRT on cognitive function should be studied in a large prospective study in a group of women in their early and late menopausal ages with periodic assessment of their cognitive function during these follow-up years.

Impact of sex and reproductive status on memory circuitry structure and function in early midlife using structural covariance analysis

Research on age-related memory alterations traditionally targets individuals aged ≥65 years. However, recent studies emphasize the importance of early aging processes. We therefore aimed to characterize variation in brain gray matter structure in early midlife as a function of sex and menopausal status. Subjects included 94 women (33 premenopausal, 29 perimenopausal, and 32 postmenopausal) and 99 demographically comparable men from the New England Family Study. Subjects were scanned with a high-resolution T1 sequence on a 3 T whole body scanner. Sex and reproductive-dependent structural differences were evaluated using Box's M test and analysis of covariances (ANCOVAs) for gray matter volumes. Brain regions of interest included dorsolateral prefrontal cortex (DLPFC), inferior parietal lobule (iPAR), anterior cingulate cortex (ACC), hippocampus (HIPP), and parahippocampus. While we observed expected significant sex differences in volume of hippocampus with women of all groups having higher volumes than men relative to cerebrum size, we also found significant differences in the covariance matrices of perimenopausal women compared with postmenopausal women. Associations between ACC and HIPP/iPAR/DLPFC were higher in postmenopausal women and correlated with better memory performance. Findings in this study underscore the importance of sex and reproductive status in early midlife for understanding memory function with aging.

Sex and gender differences in schizophrenic psychoses-a critical review

Many sex and gender differences in schizophrenic psychoses have been reported, but few have been soundly replicated. A stable finding is the later age of onset in women compared to men. Gender differences in symptomatology, comorbidity, and neurocognition seem to reflect findings in the general population. There is increasing evidence for estrogens being psychoprotective in women and for hypothalamic-pituitary-gonadal dysfunction in both sexes.More methodologically sound, longitudinal, multi-domain, interdisciplinary research investigating both sex (biological) and gender (psychosocial) factors is required to better understand the different pathogenesis and etiologies of schizophrenic psychoses in women and men, thereby leading to better tailored treatments and improved outcomes.

Sex Hormones and Healthy Psychological Aging in Women

Besides their key role in reproduction, estrogens have effects in several organs in the body, as confirmed by the identification of estrogen receptors (ER) in multiple tissues. Experimental evidence has shown that estrogens have significant impacts on the central nervous system (CNS), and a key question is to what extent the fall in estrogen levels in the blood that occurs with increasing age, particularly around and following the menopause, has an impact on the cognitive function and psychological health of women, specifically regarding mood. This review will consider direct effects of menopausal changes in estrogens on the brain, including cognitive function and mood. Secondary pathways whereby health factors affected by changes in estrogens may interact with CNS functions, such as cardiovascular factors, will be reviewed as well insofar as they also have an impact on cognitive function. Finally, because decline in estrogens may induce changes in the CNS, there is interest in clarifying whether hormone therapy may offer a beneficial balance and the impact of hormone therapy on cognition will also be considered.

Estrogens and the cognitive symptoms of schizophrenia: Possible neuroprotective mechanisms

Schizophrenia is a complex neuropsychiatric illness with marked sex differences. Women have later onset and lesser symptoms, which has led to the hypothesis that estrogens are protective in schizophrenia. Cognitive dysfunction is a hallmark of the disease and the symptom most correlated with functional outcome. Here we describe a number of mechanisms by which estrogens may be therapeutic in schizophrenia, with a focus on cognitive symptoms. We review the relationship between estrogens and brain derived neurotrophic factor, neuroinflammation, NMDA receptors, GABA receptors, and luteinizing hormone. Exploring these pathways may enable novel treatments for schizophrenia and a greater understanding of this devastating disease.

Letrozole regulates actin cytoskeleton polymerization dynamics in a SRC-1 dependent manner in the hippocampus of mice

In the hippocampus, local estrogens (E₂) derived from testosterone that is catalyzed by aromatase play important roles in the regulation of hippocampal neural plasticity, but the underlying mechanisms remain unclear. The actin cytoskeleton contributes greatly to hippocampal synaptic plasticity; however, whether it is regulated by local E₂ and the related mechanisms remain to be elucidated. In this study, we first examined the postnatal developmental profiles of hippocampal aromatase and specific proteins responsible for actin cytoskeleton dynamics. Then we used aromatase inhibitor letrozole (LET) to block local E₂ synthesis and examined the changes of these proteins and steroid receptor coactivator-1 (SRC-1), the predominant coactivator for steroid nuclear receptors. Finally, SRC-1 specific RNA interference was used to examine the effects of SRC-1 on the expression of these actin remodeling proteins. The results showed a V-type profile for aromatase and increased profiles for actin cytoskeleton proteins in both male and female hippocampus without obvious sex differences. LET treatment dramatically decreased the F-actin/G-actin ratio, the expression of Rictor, phospho-AKT (ser473), Profilin-1, phospho-Cofilin (Ser3), and SRC-1 in a dose-dependent manner. In vitro studies demonstrated that LET induced downregulation of these proteins could be reversed by E₂, and E₂ induced increase of these proteins were significantly suppressed by SRC-1 shRNA interference. These results for the first time clearly demonstrated that local E₂ inhibition could induce aberrant actin polymerization; they also showed an important role of SRC-1 in the mediation of local E₂ action on hippocampal synaptic plasticity by regulation of actin cytoskeleton dynamics.

Hormone therapy for ovarian cancer survivors: systematic review and meta-analysis

OBJECTIVE

Hormone therapy (HT) alleviates menopausal symptoms, but there is a lack of consensus regarding its use among premenopausal ovarian cancer survivors.

METHODS

We systematically reviewed the literature and searched the Medline (1966-2014), Scopus (2004-2014), Popline (1974-2014), ClinicalTrials.gov (2008-2014), and Cochrane Central Register of Controlled Trials CENTRAL (1999-2014) databases and the reference lists of electronically retrieved studies. Statistical meta-analysis was performed using RevMan 5.1 software.

RESULTS

Six studies were included in our systematic review, which involved 1,521 women. Among them, 451 women (29.6%) received HT, whereas the remaining 1,070 women (70.4%) did not receive any treatment. We noticed a statistically significant reduction of ovarian cancer-related deaths among women who received HT (odds ratio, 0.47; 95% CI, 0.28-0.80); however, disease recurrence rates did not differ between the two groups (odds ratio, 0.71; 95% CI, 0.45-1.14). Studies included in the present systematic review did not report a significant difference in overall survival and disease-free survival rates among women receiving HT and controls.

CONCLUSIONS

Based on the results of meta-analysis, HT does not influence the odds of ovarian cancer recurrence; however, this conclusion must be confirmed separately because of significant limitations in the methodological quality of the studies included.

Effect of Ovarian Hormone Therapy on Cognition in the Aged Female Rhesus Macaque

Studies of the effect of hormone therapy on cognitive function in menopausal women have been equivocal, in part due to differences in the type and timing of hormone treatment. Here we cognitively tested aged female rhesus macaques on (1) the delayed response task of spatial working memory, (2) a visuospatial attention task that measured spatially and temporally cued reaction times, and (3) a simple reaction time task as a control for motor speed. After task acquisition, animals were ovariectomized (OVX). Their performance was compared with intact controls for 2 months, at which time no group differences were found. The OVX animals were then assigned to treatment with either a subcutaneous sham implant (OVX), 17-β estradiol (E) implant (OVX+E) or E implant plus cyclic oral progesterone (OVX+EP). All groups were then tested repeatedly over 12 months. The OVX+E animals performed significantly better on the delayed response task than all of the other groups for much of the 12 month testing period. The OVX+EP animals also showed improved performance in the delayed response task, but only at 30 s delays and with performance levels below that of OVX+E animals. The OVX+E animals also performed significantly better in the visuospatial attention task, particularly in the most challenging invalid cue condition; this difference also was maintained across the 12 month testing period. Simple reaction time was not affected by hormonal manipulation. These data demonstrate that chronic, continuous administration of E can exert multiple beneficial cognitive effects in aged, OVX rhesus macaque females.

SIGNIFICANCE STATEMENT

Hormone therapy after menopause is controversial. We tested the effects of hormone replacement in aged rhesus macaques, soon after surgically-induced menopause [ovariectomy (OVX)], on tests of memory and attention. Untreated ovarian-intact and OVX animals were compared with OVX animals receiving estradiol (E) alone or E with progesterone (P). E was administered in a continuous fashion via subcutaneous implant, whereas P was administered orally in a cyclic fashion. On both tests, E-treated animals performed better than the other 3 experimental groups across 1 year of treatment. Thus, in this monkey model, chronic E administered soon after the loss of ovarian hormones had long-term benefits for cognitive function.

The Potential of Gonadal Hormone Signalling Pathways as Therapeutics for Dementia

Dementia is an ever-expanding problem facing an ageing society. Currently, there is a sharp paucity of treatment strategies. It has long been known that sex hormones, namely 17β-estradiol and testosterone, possess neuroprotective- and cognitive-enhancing qualities. However, certain lacunae in the knowledge underlying their molecular mechanisms have delayed their use as treatment strategies in dementia. With recent advancements in pharmacology and molecular biology, especially in the development of safer selective oestrogen receptor modulators and the recent discovery of the small-molecule brain-derived neurotrophic factor receptor agonist, 7,8-dihydroxyflavone, the exploitation of these signalling pathways for clinical use has become possible. This review aims to adumbrate the evidence and hurdles underscoring the use of sex hormones in the treatment of dementia as well as discussing some direction that is required to advance the translation of evidence into practise.

Genetically predicted 17beta-estradiol, cognitive function and depressive symptoms in women: A Mendelian randomization in the Guangzhou Biobank Cohort Study

OBJECTIVE

The role of estrogen in cognitive function and depressive symptoms is controversial due to discrepancies between results from randomized controlled trials (RCT) and observational studies. Mendelian randomization analysis may provide further insights concerning the role of estrogen in these outcomes as it assesses the effect of lifelong endogenous exposure but is less vulnerable to confounding than observational studies.

METHOD

We used separate sample instrumental variable analysis to estimate the association of log 17β estradiol with cognitive function (Delayed 10 word recall, and Mini Mental State Examination (MMSE)) and depressive symptoms (Geriatric Depression Scale (GDS)) in older Chinese women of the Guangzhou Biobank Cohort Study (GBCS, n=3086). The estimate was derived based on the Wald estimator, the ratio of the association of genetic determinants (rs1008805 and rs2175898) of log 17β-estradiol with cognitive function and depressive symptoms in GBCS and the association of log 17β-estradiol with genetic determinants in the sample of young women in Hong Kong (n=236).

RESULTS

Genetically predicted 17β-estradiol was not associated with delayed 10-word recall (0.42 words per log increase in 17β-estradiol (pmol/L), 95% confidence interval (CI) -0.49 to 1.34) MMSE (0.39 per log increase in 17β-estradiol (pmol/L), 95% CI -0.87 to 1.65) or GDS (0.24 per log increase in 17β-estradiol (pmol/L), 95% CI -0.57 to 1.05).

CONCLUSION

These results were largely consistent with evidence from RCTs and did not show any beneficial effect of estrogen on cognitive function and depressive symptoms. However, larger Mendelian randomization analyses are needed to identify any minor effects.

Association of bilateral oophorectomy with cognitive function in healthy, postmenopausal women

OBJECTIVE

To investigate the association between bilateral oophorectomy and cognitive performance in healthy, older women.

DESIGN

Retrospective analysis of clinical trial data.

SETTING

Academic research institution.

PATIENT(S)

Healthy postmenopausal women without signs or symptoms of cardiovascular disease or diabetes (n = 926).

INTERVENTION(S)

Randomized interventions (not the focus of this analysis) in analyzed trials included B-vitamins, soy isoflavones, oral estradiol, and matching placebos.

MAIN OUTCOME MEASURE(S)

Measures in five cognitive domains (executive functions, semantic memory, logical memory, visual memory, and verbal learning) and global cognitive function.

RESULT(S)

Using data from three clinical trials conducted under uniform conditions, bilateral oophorectomy and its timing were analyzed cross-sectionally and longitudinally in relation to cognitive function in linear regression models. Covariates included age, education, race/ethnicity, body mass index, trial, and randomized treatment (in longitudinal models). Duration of menopausal hormone use was considered as a possible mediator and effect modifier. Median age of oophorectomy was 45 years. When evaluating baseline cognition, we found that surgical menopause after 45 years of age was associated with lower performance in verbal learning compared with natural menopause. Evaluating the change in cognition over approximately 2.7 years, surgical menopause was associated with performance declines in visual memory for those who had an oophorectomy after 45 years of age and in semantic memory for those who had oophorectomy before 45 years of age compared with natural menopause. Oophorectomy after natural menopause was not associated with cognitive performance. Adjustment for duration of hormone use did not alter these associations.

CONCLUSION(S)

Cognitive associations with ovarian removal vary by timing of surgery relative to both menopause and age.

Estrogen- and progesterone-mediated structural neuroplasticity in women: evidence from neuroimaging

There is substantial evidence that the ovarian sex hormones, estrogen and progesterone, which vary considerably over the course of the human female lifetime, contribute to changes in brain structure and function. This structured, quantitative literature reviews aims to summarize neuroimaging literature addressing physiological variation in brain macro- and microstructure across an array of hormonal transitions including the menstrual cycle, use of hormonal contraceptives, pregnancy, and menopause. Twenty-five studies reporting structural neuroimaging of women, addressing variation across hormonal states, were identified from a structured search of PUBMED and were systematically reviewed. Although the studies are heterogenous with regard to methodology, overall the results point to overlapping areas of hormone related effects on brain structure particularly affecting the structures of the limbic system. These findings are in keeping with functional data that point to a role for estrogen and progesterone in mediating emotional processing.

Distinct cognitive effects of estrogen and progesterone in menopausal women

The effects of postmenopausal hormone treatment on cognitive outcomes are inconsistent in the literature. Emerging evidence suggests that cognitive effects are influenced by specific hormone formulations, and that progesterone is more likely to be associated with positive outcomes than synthetic progestin. There are very few studies of unopposed progesterone in postmenopausal women, and none that use functional neuroimaging, a sensitive measure of neurobiological function. In this study of 29 recently postmenopausal women, we used functional MRI and neuropsychological measures to separately assess the effects of estrogen or progesterone treatment on visual and verbal cognitive function. Women were randomized to receive 90 days of either estradiol or progesterone counterbalanced with placebo. After each treatment arm, women were given a battery of verbal and visual cognitive function and working memory tests, and underwent functional MRI including verbal processing and visual working memory tasks. We found that both estradiol and progesterone were associated with changes in activation patterns during verbal processing. Compared to placebo, women receiving estradiol treatment had greater activation in the left prefrontal cortex, a region associated with verbal processing and encoding. Progesterone was associated with changes in regional brain activation patterns during a visual memory task, with greater activation in the left prefrontal cortex and right hippocampus compared to placebo. Both treatments were associated with a statistically non-significant increase in number of words remembered following the verbal task performed during the fMRI scanning session, while only progesterone was associated with improved neuropsychological measures of verbal working memory compared to placebo. These results point to potential cognitive benefits of both estrogen and progesterone.

Neurite outgrowth promoting effect of 17-β estradiol is mediated through estrogen receptor alpha in an olfactory epithelium culture

Olfactory deficits are observed early in the course of chronic neurological disorders including Alzheimer's disease (AD). Estrogen treatment in post-menopausal women reduced the incidence of olfactory dysfunction, raising the possibility that estrogen treatment can cure olfactory deficits in preclinical stages of AD. In this study, we examined the estradiol׳s effects on neurite outgrowth in explant cultures of mouse olfactory epithelium (OE). We found that neurons in OE cultures treated with 100 pM 17-β estradiol (estradiol) had significantly longer neurite outgrowth than cultures treated with ethanol alone (vehicle). The OE neurons expressed estrogen receptors alpha (ERα) and ER beta (ERβ). Estrogen treatment upregulated both ERα and ERβ expression in OE culture. Treatment of OE cultures with propyl pyrazole triol (PPT), a selective agonist for ERα increased neurite outgrowth to comparable extent as estradiol treatment. In contrast, 2,3-bis-4-hydroxyphenyl (DPN), a specific agonist for ERβ, had no effect on neurite outgrowth. Furthermore, estradiol treatment increased neurite outgrowth in OE cultures derived from ERβ-deficient/knockout mice and wild-type littermates, but not in ERα-deficient/knockout mice. These data suggest that ERα mediates the neurite outgrowth promoting effects of estradiol in OE cultures. We propose that olfactory dysfunction in chronic neurological disorders, where estrogen deficiency is a risk factor, is an indicator of compromised axonal regeneration of olfactory sensory neurons.

Pharmacological blockade of the aromatase enzyme, but not the androgen receptor, reverses androstenedione-induced cognitive impairments in young surgically menopausal rats

Androstenedione, the main circulating ovarian hormone present after menopause, has been shown to positively correlate with poor spatial memory in an ovary-intact rodent model of follicular depletion, and to impair spatial memory when administered exogenously to surgically menopausal ovariectomized rats. Androstenedione can be converted directly to estrone via the aromatase enzyme, or to testosterone. The current study investigated the hormonal mechanism underlying androstenedione-induced cognitive impairments. Young adult ovariectomized rats were given either androstenedione, androstenedione plus the aromatase inhibitor anastrozole to block conversion to estrone, androstenedione plus the androgen receptor blocker flutamide to block androgen receptor activity, or vehicle treatment, and were then administered a battery of learning and memory maze tasks. Since we have previously shown that estrone administration to ovariectomized rats impaired cognition, we hypothesized that androstenedione's conversion to estrone underlies, in part, its negative cognitive impact. Here, androstenedione administration impaired spatial reference and working memory. Further, androstenedione did not induce memory deficits when co-administered with the aromatase inhibitor, anastrozole, whereas pharmacological blockade of the androgen receptor failed to block the cognitive impairing effects of androstenedione. Anastrozole alone did not impact performance on any cognitive measure. The current data support the tenet that androstenedione impairs memory through its conversion to estrone, rather than via actions on the androgen receptor. Studying the effects of aromatase and estrogen metabolism is critical to elucidating how hormones impact women's health across the lifespan, and results hold important implications for understanding and optimizing the hormone milieu from the many endogenous and exogenous hormone exposures across the lifetime.

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.

Learning and memory: Steroids and epigenetics

Memory formation and utilization is a complex process involving several brain structures in conjunction as the hippocampus, the amygdala and the adjacent cortical areas, usually defined as medial temporal lobe structures (MTL). The memory processes depend on the formation and modulation of synaptic connectivity affecting synaptic strength, synaptic plasticity and synaptic consolidation. The basic neurocognitive mechanisms of learning and memory are shortly recalled in the initial section of this paper. The effect of sex hormones (estrogens, androgens and progesterone) and of adrenocortical steroids on several aspects of memory processes are then analyzed on the basis of animal and human studies. A specific attention has been devoted to the different types of steroid receptors (membrane or nuclear) involved and on local metabolic transformations when required. The review is concluded by a short excursus on the steroid activated epigenetic mechanisms involved in memory formation.

Influences of hormone replacement therapy on olfactory and cognitive function in postmenopausal women

Olfactory dysfunction can be an early sign of Alzheimer's disease. Since hormone replacement therapy (HRT) may protect against Alzheimer's disease in postmenopausal women, the question arises as to whether it also protects against olfactory dysfunction in such women. A total of three olfactory and 12 neurocognitive tests were administered to 432 healthy postmenopausal women with varied HRT histories. Serum levels of reproductive hormones were obtained for all subjects; APOE-ε4 haplotype was determined for 77 women. National Adult Reading Test and Odor Memory/Discrimination Test scores were positively influenced by HRT. Odor Identification and Odor Memory/Discrimination Test scores were lower for women who scored poorly on a delayed recall test, a surrogate for mild cognitive impairment. The Wechsler Adult Intelligence Scale, Revised, as a Neuropsychological Instrument Spatial Span Backwards Test scores were higher in women receiving estrogen and progestin HRT and directly correlated with serum testosterone levels, the latter implying a positive effect of testosterone on spatial memory. APOE-ε4 was associated with poorer odor threshold test scores. These data suggest that HRT positively influences a limited number of olfactory and cognitive measures during menopause.

Menopause Analytical Hormonal Correlate Outcome Study (MAHCOS) and the association to brain electrophysiology (P300) in a clinical setting

Various studies have demonstrated that increased leptin levels and obesity are inversely related to cognitive decline in menopausal women. It is hypothesized that adiposity is inversely correlated with cognitive decline, as women with increased weight are less vulnerable to diminishing cognition. However, it is increasingly observed that menopausal women, even with increased adiposity, experience significant cognitive decline. Positron emission tomography (PET) has been used to analyze cognitive function and processing in menopausal women. Evoked potentials (P300) and neurophysiologic tests have validated brain metabolism in cognitively impaired patients. Post-hoc analyses of 796 female patients entering PATH Medical Clinic, between January 4, 2009 and February 24, 2013, were performed as part of the "Menopause Analytical Hormonal Correlate Outcome Study" (MAHCOS). Patient age range was 39-76 years (46.7 ± 0.2). P300 latency and amplitude correlated with a number of hormones: follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol, estrone, estriol, DHEA, pregnenolone, progesterone, free and total testosterone, thyroid stimulating hormone (TSH), Vitamins D 1.25 and D 25OH, leptin, and insulin-like growth factor-binding protein 3 (IGF-BP3). Corrected statistics did not reveal significant associations with P300 latency or amplitude for these hormones except for leptin plasma levels. However, factor analysis showed that FSH and LH clustered together with Vitamin D1.25 and Vitamin D25OH, P300 latency (not amplitude), and log leptin were found to be associated in the same cluster. Utilizing regression analysis, once age adjusted, leptin was the only significant predictor for latency or speed (p = 0.03) with an effect size of 0.23. Higher plasma leptin levels were associated with abnormal P300 speed (OR = 0.98). Our findings show a significant relationship of higher plasma leptin levels, potentially due to leptin resistance, and prolonged P300 latency. This suggests leptin resistance may delay electrophysiological processing of memory and attention, which appears to be the first of such an association.