Enhanced verbal memory in nondemented elderly women receiving hormone-replacement therapy

Estrogen: a master regulator of bioenergetic systems in the brain and body

Estrogen is a fundamental regulator of the metabolic system of the female brain and body. Within the brain, estrogen regulates glucose transport, aerobic glycolysis, and mitochondrial function to generate ATP. In the body, estrogen protects against adiposity, insulin resistance, and type II diabetes, and regulates energy intake and expenditure. During menopause, decline in circulating estrogen is coincident with decline in brain bioenergetics and shift towards a metabolically compromised phenotype. Compensatory bioenergetic adaptations, or lack thereof, to estrogen loss could determine risk of late-onset Alzheimer's disease. Estrogen coordinates brain and body metabolism, such that peripheral metabolic state can indicate bioenergetic status of the brain. By generating biomarker profiles that encompass peripheral metabolic changes occurring with menopause, individual risk profiles for decreased brain bioenergetics and cognitive decline can be created. Biomarker profiles could identify women at risk while also serving as indicators of efficacy of hormone therapy or other preventative interventions.

Geriatrics: (women's health series)

As women age, they face challenging health issues. Their average life expectancy is longer than their male counterparts, yet they often have multiple chronic, ongoing health problems that complicate their care, accentuate their infirmity, and reduce their quality of life. Often, they fail to receive the same quality or amount of healthcare service, sometimes because of a lack of data specific to their demographics, at other times for myriad unclear reasons. What data are available suggest that they will usually glean the same benefits as their male and younger female counterparts, often with little increased risk of adverse effects from available medical diagnostic and therapeutic options. Cardiovascular disease, malignancies, musculoskeletal disorders (particularly osteoporosis), and cognitive and psychiatric illness are the most frequent, and often most devastating, health issues in this growing segment of the population. An understanding of the differences in disease frequencies, presentations, and response to treatments is necessary to provide older adult women with optimal health care.

Cognitive performance in healthy women during induced hypogonadism and ovarian steroid addback

Gynecology clinic-based studies have consistently demonstrated that induced hypogonadism is accompanied by a decline in cognitive test performance. However, a recent study in healthy asymptomatic controls observed that neither induced hypogonadism nor estradiol replacement influenced cognitive performance. Thus, the effects of induced hypogonadism on cognition might not be uniformly experienced across individual women. Moreover, discrepancies in the effects of hypogonadism on cognition also could suggest the existence of specific risk phenotypes that predict a woman's symptomatic experience during menopause. In this study, we examined the effects of induced hypogonadism and ovarian steroid replacement on cognitive performance in healthy premenopausal women. Ovarian suppression was induced with a GnRH agonist (Lupron) and then physiologic levels of estradiol and progesterone were reintroduced in 23 women. Cognitive tests were administered during each hormone condition. To evaluate possible practice effects arising during repeated testing, an identical battery of tests was administered at the same time intervals in 11 untreated women. With the exception of an improved performance on mental rotation during estradiol, we observed no significant effects of estradiol or progesterone on measures of attention, concentration, or memory compared with hypogonadism. In contrast to studies in which a decline in cognitive performance was observed in women receiving ovarian suppression therapy for an underlying gynecologic condition, we confirm a prior report demonstrating that short-term changes in gonadal steroids have a limited effect on cognition in young, healthy women. Differences in the clinical characteristics of the women receiving GnRH agonists could predict a risk for ovarian steroid-related changes in cognitive performance during induced, and possibly, natural menopause.

Estrogens need insulin-like growth factor I cooperation to exert their neuroprotective effects in post-menopausal women

BACKGROUND

The abrupt fall in estrogens levels during the menopausal transition may connote an hormonal state predisposing to neurodegenerative disorders, e.g. Alzheimer's disease (AD). Reportedly, the neurotrophic activity of estrogen involves an interaction with IGF-I.

AIM

To evaluate the leukocyte gene expression of progesterone receptor (PR-A/B) and interleukin 6 (IL-6), two parameters under the control of estrogens and involved in the pathogenesis of AD.

SUBJECTS

The study was conducted in non-demented women divided into two groups according to their pre- or post-menopausal state; each group being further divided into two subgroups based on their circulating levels of IGF-I (normal or low). An additional sample of AD-affected women served as a comparison group.

RESULTS

Estrogens maintained their full activity only when IGF-I levels were in the range of normalcy. On the contrary, if the concentrations of one or both hormones were reduced, estrogens were not anymore capable to control the gene expression of PR-A/B or IL-6.

CONCLUSIONS

Before administering hormone-based replacement therapy, characterization of the somatotropic function should be performed in the early phase of the menopause.

Estrogen and the prefrontal cortex: towards a new understanding of estrogen's effects on executive functions in the menopause transition

Midlife decline in cognition, specifically in areas of executive functioning, is a frequent concern for which menopausal women seek clinical intervention. The dependence of executive processes on prefrontal cortex function suggests estrogen effects on this brain region may be key in identifying the sources of this decline. Recent evidence from rodent, nonhuman primate, and human subject studies indicates the importance of considering interactions of estrogen with neurotransmitter systems, stress, genotype, and individual life events when determining the cognitive effects of menopause and estrogen therapy.

Positive and negative affect, depression, and cognitive processes in the Cognition in the Study of Tamoxifen and Raloxifene (Co-STAR) Trial

OBJECTIVES

This study examined the relationship between positive and negative affect, depressive symptoms, and cognitive performance.

METHODS

The sample consisted of 1479 non-demented, postmenopausal women (mean age = 67 years) at increased risk of breast cancer enrolled in the National Surgical Adjuvant Breast and Bowel Project's Study of Tamoxifen and Raloxifene. At each annual visit, women completed a standardized neuropsychological battery and self-report measures of affect and depression. Data from three visits were used in linear mixed models for repeated measures using likelihood ratio tests. Separate analyses were performed to relate positive/negative affect and depression to each cognitive measure.

RESULTS

Higher positive affect was associated with better letter fluency (p = .006) and category fluency (p < .0001). Higher negative affect was associated with worse global cognitive function (p < .0001), verbal memory (CVLT List B; p = .002), and spatial ability (p < .0001). Depressive symptoms were negatively associated with verbal knowledge (p = .004), figural memory (p < .0001), and verbal memory (p's ≤ .0001).

DISCUSSION

Findings are consistent with some prior research demonstrating a link between positive affect and increased verbal fluency and between depressive symptoms and decreased memory. The most novel finding shows that negative affect is related to decreased global cognition and visuospatial ability. Overall, this research in a large, longitudinal sample supports the notion that positive affect is related to increases and negative affect to decreases in performance on distinct cognitive measures.

Neuroprotection and estrogen receptors

This review is intended to assess the state of current knowledge on the role of estrogen receptors (ERs) in the neuroprotective effects of estrogens in models for acute neuronal injury and death. We evaluate the overall evidence that estrogens are neuroprotective in acute injury and critically assess the role of ERα, ERβ, GPR 30, and nonreceptor-mediated mechanisms in these robust neuroprotective effects of this ovarian steroid hormone. We conclude that all three receptors, as well as nonreceptor-mediated mechanisms can be involved in neuroprotection, depending on the model used, the level of estrogen administrated, and the mode of administration of the steroid. Also, the signaling pathways used by both ER-dependent and ER-independent mechanisms to exert neuroprotection are considered. Finally, further studies that are needed to parse out the relative contribution of receptor versus nonreceptor-mediated signaling are discussed.

Therapeutic approaches to age-associated neurocognitive disorders

The United Nations projects that the number of individuals with dementia in developed countries alone will be approximately 36,7 million by the year 2050. International recognition of the significant emotional and economic burden of Alzheimer's disease has been matched by a dramatic increase in the development of pharmacological and nonpharmacological approaches to this illness in the past decade. Changing demographics have underscored the necessity to develop similar approaches for the remediation of the cognitive impairment associated with more benign syndromes, such as mild cognitive impairment (MCI) and age-associated cognitive decline (AACD). The present article aims to provide an overview of the most current therapeutic approaches to age-associated neurocognitive disorders. Additionally, it discusses the conceptual and methodological issues that surround the design, implementation, and interpretation of such approaches.

Greater cognitive deterioration in women than men with Alzheimer's disease: a meta analysis

Studies reporting on the cognitive abilities of men and women with Alzheimer's disease (AD) are surprisingly rare. We carried out a meta-analysis of neurocognitive data from 15 studies (n = 828 men; 1,238 women), which revealed a consistent male advantage on verbal and visuospatial tasks and tests of episodic and semantic memory. Moderator regression analyses showed that age, education level, and dementia severity did not significantly predict the male advantage. Reasons posited for this advantage include a reduction of estrogen in postmenopausal women, sex differences in AD pathology, and greater cognitive reserve in men.

Estrogens, hormone therapy, and hippocampal volume in postmenopausal women

The brain atrophies in late life. However, there are many factors that either magnify or mitigate the rate of atrophy. Loss of estrogens during menopause and administration of hormone therapy have both been hypothesized as sources of individual variation in the prevalence of cortical and subcortical atrophy and loss of cognitive function in late adulthood. In this review we critically summarize and assess the extant rodent and human neuroimaging studies that examine the link between estrogens and hippocampal morphology and function and focus predominantly on human studies of the hippocampus in postmenopausal women. Several cross-sectional studies report that the size of the hippocampus is larger in women receiving hormone therapy while several other cross-sectional studies report either negligible effects or smaller volumes in women receiving hormone therapy. We suggest that these differences might be caused by the variation between studies in the age of the samples studied, the duration of therapy, and the age at which hormone therapy is initiated. Unfortunately, all of the human studies reviewed here are cross-sectional in nature. With the lack of well-controlled randomized trials with neuroimaging measures on postmenopausal women both before and after some exposure interval, the effect of hormone therapy on hippocampal atrophy will remain equivocal and poorly understood.

Minireview: effects of different HT formulations on cognition

Evidence from preclinical studies, randomized clinical trials (RCT), and observational studies underscores the importance of distinguishing among the different forms of estrogen and progestogens when evaluating the cognitive effects of hormone therapy (HT) in women. Despite this evidence, there is a lack of direct comparisons of different HT regimens. To provide insights into the effects of different HT formulations on cognition, this minireview focuses on RCT of verbal memory because evidence indicates that HT affects this cognitive domain more than others and because declines in verbal memory predict later development of Alzheimer's disease. Some observational studies indicate that estradiol confers benefits to verbal memory, whereas conjugated equine estrogens (CEE) confer risks. RCT to date show no negative impact of CEE on verbal memory, including the Women's Health Initiative Study of Cognitive Aging. Similarly, the Women's Health Initiative Memory Study showed no negative impact of CEE on dementia. Transdermal estradiol in younger postmenopausal women improved verbal memory in one small RCT but had no effect in another RCT. RCT of oral estradiol in younger and older postmenopausal women had neutral effects on cognitive function. In contrast, RCT show a negative impact of CEE plus medroxyprogesterone acetate on verbal memory in younger and older postmenopausal women. Small RCT show neutral or beneficial effects of other progestins on memory. Overall, RCT indicate that type of progestogen is a more important determinant of the effects of HT on memory than type of estrogen.

Building a better hormone therapy? How understanding the rapid effects of sex steroid hormones could lead to new therapeutics for age-related memory decline

A wealth of data collected in recent decades has demonstrated that ovarian sex-steroid hormones, particularly 17β-estradiol (E2), are important trophic factors that regulate the function of cognitive regions of the brain such as the hippocampus. The loss of hormone cycling at menopause is associated with cognitive decline and dementia in women, and the onset of memory decline in animal models. However, hormone therapy is not currently recommended to prevent or treat cognitive decline, in part because of its detrimental side effects. In this article, it is proposed that investigations of the rapid effects of E2 on hippocampal function be used to further the design of new drugs that mimic the beneficial effects of E2 on memory without the side effects of current therapies. A conceptual model is presented for elucidating the molecular and biochemical mechanisms through which sex-steroid hormones modulate memory, and a specific hypothesis is proposed to account for the rapid memory-enhancing effects of E2. Empirical support for this hypothesis is discussed as a means of stimulating the consideration of new directions for the development of hormone-based therapies to preserve memory function in menopausal women.

Interactive effects of estrogen and serotonin on brain activation during working memory and affective processing in menopausal women

While cognitive changes and mood instability are frequent symptoms reported by menopausal women, the degree to which the decline in estrogen production is responsible is not yet clear. Several lines of evidence suggest that estrogen may produce its effects on cognition and mood through modulation of serotonergic function. To test this hypothesis, we used the tryptophan depletion (TD) paradigm to lower central serotonin levels and pharmacologically manipulated estrogen levels in healthy menopausal women. We examined the individual and combined effects of estradiol and serotonin on working memory, emotion processing and task-related brain activation. Eight healthy predominantly early postmenopausal women underwent TD or sham depletion followed by functional magnetic resonance imaging (fMRI) both before and after short-term transdermal estradiol 75-150 μg/d administration. There was an estradiol treatment by TD interaction for brain activation during performance on both the N-back Task (working memory) and Emotion Identification Task (affective processing). During the 2-back condition, TD attenuated activation prior to, but not after, estradiol treatment in the right and left dorsal lateral prefrontal and middle frontal/cingulate gyrus. During emotion identification, TD heightened activation in the orbital frontal cortex and bilateral amygdala, and this effect was attenuated by estradiol treatment. These results provide preliminary evidence that serotonergic effects directly mediate the impact of estrogen on brain activation during working memory and affective processing.

Estradiol treatment altered anticholinergic-related brain activation during working memory in postmenopausal women

Estradiol has been shown to affect cholinergic modulation of cognition in human and nonhuman animal models. This study examined the brain-based interaction of estradiol treatment and anticholinergic challenge in postmenopausal women during the performance of a working memory task and functional MRI. Twenty-four postmenopausal women were randomly and blindly placed on 1mg oral 17-β estradiol or matching placebo pills for three months after which they participated in three anticholinergic challenge sessions. During the challenge sessions, subjects were administered the antimuscarinic drug scopolamine, the antinicotinic drug mecamylamine, or placebo. After drug administration, subjects completed an fMRI session during which time they performed a visual verbal N-back test of working memory. Results showed that scopolamine increased activation in the left medial frontal gyrus (BA 10) and mecamylamine increased activation in the left inferior frontal gyrus (BA 46). Estradiol treatment compared to placebo treatment significantly reduced the activation in this left medial frontal region during scopolamine challenge. Estradiol treatment also increased activation in the precuneus (BA 31) during mecamylamine challenge. These data are the first to show that estradiol modulated antimuscarinic- and anitnicotinic-induced brain activity and suggest that estradiol affected cholinergic system regulation of cognition-related brain activation in humans.

The potential for estrogens in preventing Alzheimer's disease and vascular dementia

Estrogens are the best-studied class of drugs for potential use in the prevention of Alzheimer's disease (AD). These steroids have been shown to be potent neuroprotectants both in vitro and in vivo, and to exert effects that are consistent with their potential use in prevention of AD. These include the prevention of the processing of amyloid precursor protein (APP) into beta-amyloid (Aß), the reduction in tau hyperphosphorylation, and the elimination of catastrophic attempts at neuronal mitosis. Further, epidemiological data support the efficacy of early postmenopausal use of estrogens for the delay or prevention of AD. Collectively, this evidence supports the further development of estrogen-like compounds for prevention of AD. Several approaches to enhance brain specificity of estrogen action are now underway in an attempt to reduce the side effects of chronic estrogen therapy in AD.

Estrogen replacement therapy and cognitive functions in healthy postmenopausal women: a randomized trial

This study aimed to evaluate the effect of estrogen replacement therapy on verbal cognitive performance of middle-aged postmenopausal women. Middle-aged (40 to 59 years) hysterectomized, oligosymptomatic women receiving 0.625 mg/day of conjugated equine estrogens (N = 27) or placebo (N = 32) in a double-blind parallel group design were compared according to their performance on a verbal memory battery before and after six 28-day cycles of treatment. Both groups had similar age and educational level. The estrogen group performed better on digit span-forward and on the recall of the easy stimuli on the verbal-paired associates test regardless of age, education, physical symptoms, number of years of menopause, or blood estradiol levels. However, the small magnitude of difference in the effect on attentional span suggests that the estrogen-related improvement is unlikely to be of clinical relevance. Estrogen replacement therapy did not improve verbal memory in middle-aged, hysterectomized, postmenopausal, asymptomatic women.

Cognitive response to estradiol in postmenopausal women is modified by high cortisol

Estradiol has potent favorable effects on brain function and behavior in animals while in human trials, the results are inconsistent. A number of potential mediating variables influencing response to estradiol have been proposed to account for this variability, 1 of which includes stress. We conducted a placebo-controlled study to examine joint and independent effects of estradiol and elevated levels of the stress hormone cortisol on cognition and biomarkers of aging and neurodegenerative disease. Thirty-nine healthy postmenopausal women (56-84 years) received 0.10 mg/dL of transdermal 17β-estradiol (E2) or placebo for 8 weeks. During the last 4 days of the trial, subjects also received 90 mg/day (30 mg 3×/day) of oral hydrocortisone (CORT) to induce stress-level elevations in cortisol, or a matched placebo. The 4 groups thus included placebo (placebo patch/placebo pill), CORT-alone (placebo patch/hydrocortisone), E2-alone (estradiol patch/placebo pill), and E2+CORT (estradiol patch/hydrocortisone). Eight weeks of E2 increased plasma estradiol by 167%, and 4 days of CORT increased plasma cortisol by 119%. Overall, E2 had favorable effects on verbal memory (p = 0.03), working memory (p = 0.02), and selective attention (p = 0.04), and the magnitude of these effects was attenuated for E2+CORT. E2-alone and E2+CORT had opposing effects on plasma levels of the amyloid-β (Aβ) biomarker (Aβ40/42 ratio, p < 0.05), with the more favorable response observed for E2-alone. CORT-induced increases in insulin-like growth factor-1 were blunted by E2 coadministration. Our findings indicate that cognitive and physiological responses to estradiol are adversely affected by elevated stress hormone levels of cortisol in healthy postmenopausal women.

A randomized pilot trial of estrogen replacement therapy in post-menopausal women with Parkinson's disease

OBJECTIVE

To assess short-term safety and tolerability of estrogen replacement therapy in post-menopausal women with Parkinson's disease (PD).

METHODS

In a multi-center randomized, double-blind, placebo-controlled pilot trial, post-menopausal women with PD and motor fluctuations received either 0.625 mg/day of conjugated equine estrogens or matching placebo for 8 weeks. The primary outcome was the ability of participants to complete the trial. Other outcome measures included adverse events and changes from baseline to Week 8 in Unified PD Rating Scale scores, "on" time, dyskinesia ratings, and neuropsychological test results.

RESULTS

Twenty-three women (age 62.9(6.3) years, total Unified PD Rating 25.0(13.4), 8.8(6.0) years since symptom onset) were enrolled. There were no serious adverse events. One subject withdrew due to worsening of tremor and dystonia. The most commonly reported adverse events were vaginal spotting, breast enlargement and breast tenderness. The estrogen group showed improved total and motor Unified PD Rating scores although these did not reach statistical significance (mean changes from baseline, estrogen vs. placebo: Total -5.0 vs. 2.8, treatment effect = -7.8, p = 0.10; Motor -3.0 vs. 2.4, treatment effect = -5.4, p = 0.16).

CONCLUSIONS

Estrogen replacement therapy was safe and well-tolerated over 8 weeks in post-menopausal women with advanced PD. This pilot data suggests that estrogen replacement may be associated with improvement in motor symptoms. While larger studies of longer duration are necessary to determine the effects of estrogen in PD, the complex risk/benefit profile and continued controversy surrounding estrogen are obstacles to clinical trials.

Sex hormone therapy and functional brain plasticity in postmenopausal women

Several studies have shown that fluctuating levels of sex hormones (estrogen and progesterone) can affect fundamental principles of brain organization, including functional cerebral asymmetries (FCAs) and interhemispheric interactions. The majority of findings come from studies investigating younger women tested during distinct hormonal phases of the menstrual cycle, an approach that does not necessarily allow for conclusions about the causal relationship between hormonal changes and functional brain organization. An alternative approach is to manipulate the hormonal status of participants directly. This research focuses on the effects of hormone therapy (HT) on FCAs and interhemispheric interactions in postmenopausal women. Functional brain organization was tested in postmenopausal women using either estrogen therapy or combined estrogen plus gestagen therapy. The results are then compared to age- and IQ-matched postmenopausal women not taking HT. The results indicate HT-related modulations in both FCAs and interhemispheric interaction. In contrast to normally cycling women, however, it seems that HT, and especially estrogen therapy, after menopause affects intrahemispheric processing rather than interhemispheric crosstalk. The findings indicate a faster and more pronounced age-related decline in intrahemispheric relative to interhemispheric processing which seems to be accompanied by a higher sensitivity to HT. Aging processes together with differences in the hormonal status (exogenous changes as a result of HT vs. endogenous changes during the menstrual cycle) may also explain divergent (cognitive) behavioral outcomes in postmenopausal women and younger women. Taken together, the findings suggest that the female brain retains its plasticity even after reproductive age and remains susceptible to the effects of sex hormones throughout the lifetime. This article is part of a Special Issue entitled: Neuroactive Steroids: Focus on Human Brain.

Effects of herbal and dietary supplements on cognition in menopause: a systematic review

OBJECTIVE

Many postmenopausal women use herbal remedies and dietary supplements to counteract menopausal symptoms, including the decline in cognitive function. The aim of this systematic review is to evaluate the evidence regarding the efficacy of herbal and dietary supplements on cognition in menopause.

DESIGN

Randomized clinical trials (RCTs) of herbal medicines and dietary supplements were identified using the Medline, EMBASE, AMED, PsycINFO, CINAHL and The Cochrane Library 2010 (Issue 2) electronic databases and by hand searches. Data were independently extracted and evaluated by two reviewers. Risk of bias was assessed by two independent reviewers using the Cochrane Collaboration tool.

RESULTS

Twelve RCTs were included and five of these suggest that isoflavone, soy and Gingko biloba supplementation may improve cognition in postmenopausal women. However, most of the included studies had serious methodological flaws which demand a cautious interpretation of these findings.

CONCLUSIONS

The evidence that herbal and dietary supplements might positively affect the cognitive decline during the menopause is not compelling.

Effect of progesterone on phosphamidon-induced impairment of memory and oxidative stress in rats

Progesterone (a neurosteroid) is an important modulator of the nervous system functioning. Organophosphorus pesticides like phosphamidon have been shown to adversely affect memory and induce oxidative stress on both acute and chronic exposure. The present study was therefore designed to investigate the effects of progesterone (PROG) on phosphamidon-induced modulation of cognitive function and oxidative stress in rats. Cognitive function was assessed using step-down latency (SDL) on a passive avoidance apparatus and transfer latency (TL) on an elevated plus maze. Oxidative stress was assessed by examining the levels of thiobarbituric acid reactive species (TBARS) and non-protein thiols (NP-SH) in isolated homogenized whole brain samples. The results showed a significant reduction in SDL and prolongation of TL in the phosphamidon (1.74 mg/kg/d; p.o.) treated group at weeks 6 and 8 as compared to the control group. Two weeks treatment with PROG (15 mg/kg/d; i.p.) antagonized the effect of phosphamidon on SDL as well as TL. Phosphamidon alone produced a significant increase in the brain TBARS levels and decrease in the brain NP-SH levels. Treatment with PROG (15 mg/kg/d; i.p.) attenuated the effect of phosphamidon on oxidative stress. Together, the results showed that progesterone attenuated the cognitive dysfunction and increased oxidative stress induced by phosphamidon in the brain.

The impact of age-related ovarian hormone loss on cognitive and neural function

On average, women now live one-third of their lives after menopause. Because menopause has been associated with an elevated risk of dementia, an increasing body of research has studied the effects of reproductive senescence on cognitive function. Compelling evidence from humans, nonhuman primates, and rodents suggests that ovarian sex-steroid hormones can have rapid and profound effects on memory, attention, and executive function, and on regions of the brain that mediate these processes, such as the hippocampus and prefrontal cortex. This chapter will provide an overview of studies in humans, nonhuman primates, and rodents that examine the effects of ovarian hormone loss and hormone replacement on cognitive functions mediated by the hippocampus and prefrontal cortex. For humans and each animal model, we outline the effects of aging on reproductive function, describe how ovarian hormones (primarily estrogens) modulate hippocampal and prefrontal physiology, and discuss the effects of both reproductive aging and hormone treatment on cognitive function. Although this review will show that much has been learned about the effects of reproductive senescence on cognition, many critical questions remain for future investigation.

Is systemic anti-cancer therapy neurotoxic? Does chemo brain exist? And should we rename it?

The existence of chemo brain has become almost universally accepted, although many details of the concept are controversial. Data about the different types of cognitive impairment and their duration are not always consistent in the literature. We still do not know which cytotoxic agents are responsible, which characteristics make patients vulnerableand which biologic mechanisms are involved. This chapter reviews the recent literature and provides an actualized definition of chemo brain, including recent functional imaging data and discusses its controversial aspects. Potential underlying mechanisms and their future possible clinical applications in the prevention and treatment of chemo brain are also discussed. These issues are of clinical importance given the prevalence of breast carcinoma, the increased use of chemotherapy as adjuvant therapy, the increasing use of more aggressive dosing schedules and the increasing survival rates. Better-designed future trials should lead to a better definition and understanding of chemo brain and to future therapies.

Mnemonic effects of progesterone to mice require formation of 3alpha,5alpha-THP

Ovarian hormones organize and activate neural circuits for reproduction and may also mediate cognition. Research has focused on estradiol's mnemonic effects, albeit progesterone covaries with estradiol and its mechanisms for cognition require attention. Studies tested the hypothesis that cognitive effects of progesterone occur subsequent to its metabolism to 5alpha-pregnan-3alpha-ol-20-one (3alpha,5alpha-THP), which does not bind progestin receptors. Cognitive performance and progestogen levels in plasma, hippocampus, and cortex were determined in ovariectomized mice administered vehicle, or progestins that differentially form 3alpha,5alpha-THP and bind progestin receptors (progesterone, 3alpha,5alpha-THP, and/or medroxyprogesterone acetate). Only treatments that increased 3alpha,5alpha-THP levels during memory consolidation (progesterone, 3alpha,5alpha-THP, 3alpha-5alpha-THP plus medroxyprogesterone acetate, but not progesterone plus medroxyprogesterone acetate) improved cognitive performance. Thus, formation of 3alpha,5alpha-THP may be required for progesterone's cognitive-enhancing effects.

Cognitive effects of aromatase inhibitor therapy in peripubertal boys

OBJECTIVE

Aromatase inhibitors, blockers of oestrogen biosynthesis, have emerged as a new potential treatment modality for boys with short stature. The cognitive effects of such therapy are unknown. In this study, we explored the effects of aromatase inhibition on cognitive performance in peripubertal boys.

DESIGN

Prospective, double-blind, randomised, placebo-controlled clinical study.

METHODS

Twenty-eight boys, aged 9.0-14.5 years, with idiopathic short stature were treated with the aromatase inhibitor letrozole (2.5 mg/day) or placebo, for 2 years. During the treatment, the progression of physical signs of puberty and the concentrations of sex hormones were followed up. A selection of cognitive tests, focusing on memory function, was administered to the participants at entry, at 12 months and at 24 months after the start of the treatment.

RESULTS

Letrozole effectively inhibited the conversion of androgen to oestrogen, as indicated by high serum testosterone and low serum oestradiol concentrations in letrozole-treated boys who progressed into puberty. In both the groups, there was a gain in performance during the follow-up period in tests of verbal performance, in most of the tests of visuospatial performance and in some tests of verbal memory. No significant differences between the letrozole- and placebo-treated boys in development of cognitive performance were found in any of the tests during the follow-up period.

CONCLUSIONS

Our results suggest that blockade of oestrogen biosynthesis with an aromatase inhibitor does not influence cognitive performance in peripubertal males.

Estrogen treatment impairs cognitive performance after psychosocial stress and monoamine depletion in postmenopausal women

OBJECTIVE

Recent studies have shown that women experience an acceleration of cognitive problems after menopause and that estrogen treatment can improve or at least maintain current levels of cognitive functioning in postmenopausal women. However, we have previously shown that the negative emotional effects of psychosocial stress are magnified in normal postmenopausal women after estrogen treatment. This study examined whether estradiol (E2) administration can modify cognitive performance after exposure to psychological stress and monoamine depletion.

METHODS

Participants consisted of 22 postmenopausal women placed on either oral placebo or 17beta-E2 (1 mg/d for 1 mo, then 2 mg/d for 2 mo). At the end of the 3-month treatment phase, participants underwent three depletion challenges in which they ingested one of three amino acid mixtures: deficient in tryptophan, deficient in phenylalanine/tyrosine, or balanced. Five hours later, participants performed the Trier Social Stress Test (TSST), followed by mood and anxiety ratings and cognitive testing. Cognitive measures included tests of attention, psychomotor function, and verbal episodic memory.

RESULTS

E2-treated compared with placebo-treated participants exhibited significant worsening of cognitive performance on tasks measuring attentional performance and psychomotor speed. Similar trends for impairment were seen in measures of long-term episodic memory compared with placebo-treated postmenopausal women. E2-treated participants also showed a significant increase in negative mood and anxiety compared with placebo-treated women after, but not before, the TSST, although the worsening of both cognitive and behavioral functioning was not correlated. These effects were independent of tryptophan or tyrosine/phenylalanine depletion and were not manifested before the TSST or at baseline.

CONCLUSIONS

These data suggest that the relationship between estrogen administration and cognitive/behavioral performance in postmenopausal women may be more complex than initially appreciated and that the effects of psychosocial stress may influence whether hormone effects are beneficial.

A cross-sectional study of hormone treatment and hippocampal volume in postmenopausal women: evidence for a limited window of opportunity

The influence of hormone treatment on brain and cognition in postmenopausal women has been a controversial topic. Contradictory patterns of results have prompted speculation that a critical period, or limited window of opportunity, exists for hormone treatment to protect against neurocognitive. In this cross-sectional study of 102 postmenopausal women, we examined whether hippocampal, amygdala, or caudate nucleus volumes and spatial memory performance were related to the interval between menopause and the initiation of hormone treatment. Consistent with a critical period hypothesis, we found that shorter intervals between menopause and the initiation of hormone treatment were associated with larger hippocampal volumes compared with longer intervals between menopause and treatment initiation. Initiation of hormone treatment at the time of menopause was also associated with larger hippocampal volumes when compared with peers who had never used hormone treatment. Furthermore, these effects were independent from potentially confounding factors such as age, years of education, the duration of hormone treatment, current or past use of hormone therapy, the type of therapy, and age at menopause. Larger hippocampal volumes in women who initiated hormone treatment at the time of menopause failed to translate to improved spatial memory performance. There was no relationship between timing of hormone initiation, spatial memory performance, and amygdala or caudate nucleus volume. Our results provide support for a limited window of opportunity for hormone treatment to influence hippocampal volume, yet the degree to which these effects translate to improved memory performance is uncertain.

Impact of dietary genistein and aging on executive function in rats

Genistein is an estrogenic soy isoflavone widely promoted for healthy aging, but its effects on cognitive function are not well-understood. We examined the cognitive effects of once daily oral genistein treatment at two doses (approximately 162 microg/kg/day low dose and a 323 microg/kg/day high dose) in ovariectomized young (7 month), middle-aged (16 month), and old (22 month) Long-Evans rats. Operant tasks including delayed spatial alternation (DSA), differential reinforcement of low rates of responding (DRL), and reversal learning that tap prefrontal cortical function were used to assess working memory, inhibitory control/timing, and strategy shifting, respectively. At the conclusion of cognitive testing, brains were collected and relative densities of D1 and D2 dopamine receptors and dopamine transporter (DAT) were measured in the prefrontal cortex. On the DSA task, the high dose old group performed worse than both the high dose young and middle-aged groups. On the DRL task, the high dose of genistein resulted in a marginally significant impairment in the ratio of reinforced to non-reinforced lever presses. This effect was present across age groups. Age effects were also found as old rats performed more poorly than the young and middle-aged rats on the DSA overall. In contrast, middle-aged and old rats made fewer lever presses on the DRL than did the young rats, a pattern of behavior associated with better performance on this task. Moreover, while DAT levels overall decreased with age, genistein treatment produced an increase in DAT expression in old rats relative to similarly aged control rats. D1 and D2 densities did not differ between genistein dose groups or by age. These results highlight the fact that aspects of executive function are differentially sensitive to both genistein exposure and aging and suggest that altered prefrontal dopamine function could potentially play a role in mediating these effects.

Reversal of propoxur-induced impairment of memory and oxidative stress by 4'-chlorodiazepam in rats

Carbamate pesticides like propoxur have been shown to adversely affect memory and induce oxidative stress on both acute and chronic exposure. The present study was designed to explore the modulation of the effects of propoxur over cognitive function by progesterone (PROG) and 4'-chlorodiazepam (4CD). Cognitive function was assessed using step-down latency (SDL) on a passive avoidance apparatus, transfer latency (TL) on a plus maze and spatial navigation test on Morris water maze. Oxidative stress was assessed by examining brain malondialdehyde (MDA) and reduced glutathione (GSH) levels and catalase (CAT) activity. A significant reduction in SDL and prolongation of TL and spatial navigation test was found for the propoxur (10 mg/kg/d; p.o.) treated group at weeks 6 and 7 as compared with control. One-week treatment with 4CD (0.5 mg/kg/d; i.p.) antagonized the effect of propoxur on SDL, spatial navigation test as well as TL; whereas, PROG failed to modulate this effect at a dose of 15 mg/kg/d, i.p. Propoxur produced a statistically significant increase in the brain MDA levels and decrease in the brain GSH levels and CAT activity. Treatment with 4CD at the above dose attenuated the effect of propoxur on oxidative stress whereas PROG (15 mg/kg/d; i.p.) failed to influence the same. The results of the present study thus show that 4-CD has the potential to attenuate cognitive dysfunction and oxidative stress induced by toxicants like propoxur in the brain.

Effects of conjugated equine estrogens on cognition and affect in postmenopausal women with prior hysterectomy

CONTEXT

Different menopausal hormone therapies may have varied effects on specific cognitive functions. We previously reported that conjugated equine estrogens (CEE) with medroxyprogesterone acetate had a negative impact on verbal memory but tended to impact figural memory positively over time in older postmenopausal women.

OBJECTIVE

The objective of the study was to determine the effects of unopposed CEE on changes in domain-specific cognitive function and affect in older postmenopausal women with prior hysterectomy.

DESIGN

This was a randomized, double blind, placebo-controlled clinical trial.

SETTING

The study was conducted at 14 of 40 Women's Health Initiative (WHI) clinical centers.

PARTICIPANTS

Participants were 886 postmenopausal women with prior hysterectomy, aged 65 yr and older (mean 74 yr), free of probable dementia, and enrolled in the WHI and WHI Memory Study (WHIMS) CEE-Alone trial for a mean of 3 yr and followed up for a mean of 2.70 yr.

INTERVENTION

Intervention was 0.625 mg of CEE daily or placebo.

MAIN OUTCOME MEASURES

Annual rates of change in specific cognitive functions and affect, adjusted for time since randomization, were measured.

RESULTS

Compared with placebo, unopposed CEE was associated with lower spatial rotational ability (P < 0.01) at initial assessment (after 3 yr of treatment), a difference that diminished over 2.7 yr of continued treatment. CEE did not significantly influence change in other cognitive functions and affect.

CONCLUSIONS

CEE did not improve cognitive functioning in postmenopausal women with prior hysterectomy. CEE was associated with lower spatial rotational performance after an average of 3 yr of treatment. Overall, CEE does not appear to have enduring effects on rates of domain-specific cognitive change in older postmenopausal women.

Soya isoflavone supplementation enhances spatial working memory in men

Females perform better in certain memory-related tasks than males. Sex differences in cognitive performance may be attributable to differences in circulating oestrogen acting on oestrogen beta receptors (ERbeta) which are prevalent in brain regions such as the hippocampus, frontal lobe and cortex that mediate cognitive functions. Since soya isoflavones are known to activate ERbeta, chronic isoflavone supplementation in males may improve cognitive performance in memory-related tasks. A 12-week double-blind, placebo-controlled cross-over trial was conducted in thirty-four healthy men to investigate the effect of isoflavone supplementation on cognitive function. Volunteers were randomised to take four capsules/d containing soya isoflavones (116 mg isoflavone equivalents/d: 68 mg daidzein, 12 mg genistein, 36 mg glycitin) or placebo for 6 weeks, and the alternate treatment during the following 6 weeks. Assessments of memory (verbal episodic, auditory and working), executive function (planning, attention, mental flexibility) and visual-spatial processing were performed at baseline and after each treatment period. Isoflavone supplementation significantly improved spatial working memory (P = 0.01), a test in which females consistently perform better than males. Compared with placebo supplementation, there were 18 % fewer attempts (P = 0.01), 23 % fewer errors (P = 0.02) and 17 % less time (P = 0.03) required to correctly identify the requisite information. Isoflavones did not affect auditory and episodic memory (Paired Associate Learning, Rey's Auditory Verbal Learning Task, Backward Digit Span and Letter-Number Sequencing), executive function (Trail Making and Initial Letter Fluency Task) or visual-spatial processing (Mental Rotation Task). Isoflavone supplementation in healthy males may enhance cognitive processes which appear dependent on oestrogen activation.

Chronic estradiol replacement impairs performance on an operant delayed spatial alternation task in young, middle-aged, and old rats

The current study examined effects of chronic estradiol replacement on a prefrontally-mediated working memory task at different ages in a rodent model. Ovariectomized young, middle-aged, and old Long-Evans rats were given 5% or 10% 17beta-estradiol in cholesterol vehicle via Silastic implants and tested on an operant delayed spatial alternation task (DSA). The two estradiol exposed groups did not perform as well as the vehicle control group did. Deficits were present at all but the longest delay, where all groups including the vehicle control group performed poorly. Surprisingly, there was not a significant effect of age or an age by estradiol interaction, despite the fact that old rats had longer latencies to respond after both correct and incorrect lever presses. These data confirm our earlier finding that chronic estradiol treatment has an impairing effect on working memory as measured on DSA task. However, contrary to expectations, young, middle-aged and old rats were similarly impaired by chronic estradiol treatment; there were no indications of differential effects at different periods of the lifespan. Also contrary to expectations, there were no indications of a decline in DSA performance with advancing age. Overall, the results demonstrate that chronic estradiol exposure causes deficits in the DSA performance of ovariectomized female rats, not only in young adulthood, but also at older ages analogous to those at which hormone replacement therapy is commonly prescribed in humans.

Women and HIV infection: the makings of a midlife crisis

With the advent of highly active antiretroviral agents, women with HIV infection can expect to live longer than ever before. This increased survival has led to concerns about the long-term implications of HIV disease and its treatment. Women with HIV infection appear to lose ovarian function earlier in life than women without HIV infection. They also have evidence of reduced bone mineral density and increased cardiovascular risk. Moreover, many of these increases in risk factors are present even prior to the menopausal transition. All of these risks, present at midlife, augur poorly for future health and describe a substantially increased burden of disease likely to accrue to HIV-infected women as they enter older age groups. Further compounding the adversity faced by the HIV infected, the demographics of women most vulnerable to this disease include adverse social and economic influences, both of which worsen their long-term prognosis. For example, drug use and poverty are related to more severe menopausal symptoms and chronic stress is related to worse psychological and cardiovascular risk. An understanding of how menopause interacts with HIV infection is therefore most important to alert the clinician to perform surveillance for common health problems in postmenopausal women, and to address directly and appropriately symptomatology during the menopausal transition.

Homocysteine, estrogen and cognitive decline

BACKGROUND

Factors that contribute to cognitive decline in women from midlife remain poorly understood. There are circumstantial data indicating a positive association between homocysteine and cognitive decline and that endogenous and exogenous estrogen may influence homocysteine levels. The aim of this review was to establish what is known of the relationships between cognitive change and homocysteine levels, and the impact of the menopause transition and exogenous estrogen on homocysteine levels.

METHODS

We reviewed the recent published literature from 1993 to 2005 pertaining to the current understanding of the relationship(s) between plasma homocysteine levels and cognitive functioning and endogenous hormone levels and exogenous estrogen use in women.

RESULTS

Hyperhomocysteinemia is consistently associated with cognitive decline. Dietary supplementation with vitamins may assist in normalizing homocysteine levels; however, there is no evidence that this results in favorable effects on cognition. Changes in endogenous estrogen levels are inversely associated with changes in serum homocysteine. Consistent with this, estrogen therapy is associated with reductions in plasma homocysteine, with the greatest effects reported in women with higher levels of homocysteine at baseline. Limited data indicate that tibolone is associated with little change in homocysteine. The use of raloxifene, the most studied selective estrogen receptor modulator, is associated with a modest reduction in homocysteine.

CONCLUSIONS

There are data to suggest an underlying link between homocysteine levels and cognitive decline. There is also evidence for a link between both the menopause transition and use of exogenous estrogen therapy and homocysteine levels. Clinical data do not support a role for exogenous estrogen in the prevention of dementia in older women; however, the 'window of opportunity' theory suggests that there is a need for randomized controlled trials to evaluate the role of estrogen in the early postmenopausal years to protect against cognitive decline in later life.

Dorsal hippocampal progesterone infusions enhance object recognition in young female mice

The effects of progesterone on memory are not nearly as well studied as the effects of estrogens. Although progesterone can reportedly enhance spatial and/or object recognition in female rodents when given immediately after training, previous studies have injected progesterone systemically, and therefore, the brain regions mediating this enhancement are not clear. As such, this study was designed to determine the role of the dorsal hippocampus in mediating the beneficial effect of progesterone on object recognition. Young ovariectomized C57BL/6 mice were trained in a hippocampal-dependent object recognition task utilizing two identical objects, and then immediately or 2 h afterwards, received bilateral dorsal hippocampal infusions of vehicle or 0.01, 0.1, or 1.0 microg/microl water-soluble progesterone. Forty-eight hours later, object recognition memory was tested using a previously explored object and a novel object. Relative to the vehicle group, memory for the familiar object was enhanced in all groups receiving immediate infusions of progesterone. Progesterone infusion delayed 2 h after training did not affect object recognition. These data suggest that the dorsal hippocampus may play a critical role in progesterone-induced enhancement of object recognition.

Reproductive period and cognitive function in a representative sample of naturally postmenopausal women aged 60–64 years

BACKGROUND

Greater lifetime estrogen exposure has been postulated to result in better cognition in later life, particularly in the area of verbal memory. In women, the highest levels of endogenous estrogen occur during their reproductive period, between menarche and menopause.

OBJECTIVE

To investigate the association between reproductive period and cognition.

METHODS

The sample consisted of 760 naturally postmenopausal women aged 60-64 years (mean age 62.5 +/- 1.5 years) participating in the PATH Through Life Study who were randomly drawn from the population of Canberra, Australia. Participants were administered a verbal learning test (immediate recall and 1-minute delay), the Mini-Mental State Examination (MMSE), digit span backwards, the Symbol-Digit Modalities Test and simple and choice reaction time tests.

RESULTS

There were no significant associations detected between reproductive period and performance on any of the cognitive tests, either before or after controlling for potential confounding variables.

CONCLUSIONS

Reproductive period, a surrogate measure of endogenous estrogen exposure, had no detectable effect on cognitive performance in this sample.

Hormone therapy and cognitive function

BACKGROUND

Clinical trials yield discrepant information about the impact of hormone therapy on verbal memory and executive function. This issue is clinically relevant because declines in verbal memory are the earliest predictor of Alzheimer's disease and declines in executive function are central to some theories of normal, age-related changes in cognition.

METHODS

We conducted a systematic review of randomized clinical trials of hormone therapy (i.e. oral, transdermal, i.m.) and verbal memory, distinguishing studies in younger (i.e. <or=65 years of age; n = 9) versus older (i.e. >65 years; n = 7) women and studies involving estrogen alone versus estrogen plus progestogen. Out of 32 placebo-controlled trials, 17 were included (13 had no verbal memory measures and 2 involved cholinergic manipulations). We also provide a narrative review of 25 studies of executive function (two trials), since there are insufficient clinical trial data for systematic review.

RESULTS

There is some evidence for a beneficial effect of estrogen alone on verbal memory in younger naturally post-menopausal women and more consistent evidence from small-n studies of surgically post-menopausal women. There is stronger evidence of a detrimental effect of conjugated equine estrogen plus medroxyprogesterone acetate on verbal memory in younger and older post-menopausal women. Observational studies and pharmacological models of menopause provide initial evidence of improvements in executive function with hormone therapy.

CONCLUSIONS

Future studies should include measures of executive function and should address pressing clinical questions; including what formulation of combination hormone therapy is cognitively neutral/beneficial, yet effective in treating hot flashes in the early post-menopause.

Mechanisms of action of estrogen in the brain: insights from human neuroimaging and psychopharmacologic studies

Use of estrogen therapy in the perimenopausal and postmenopausal periods has been shown in several clinical trials to help women maintain a premenopausal level of cognitive function. What is not yet fully understood is how the neurobiological effects of estrogen contribute to these cognitive effects. This review explores data from two related bodies of human literature that provide compelling evidence in support of the biological plausibility that estrogen treatment can benefit cognition. The first half of the literature review focuses on studies from the estrogen neuroimaging literature, and the second half focuses on pharmacologic challenge studies assessing estrogen-neurotransmitter interactions. We integrate these two bodies of literature by focusing on the neurophysiologic underpinnings of estrogen effects on cognition and linking these clinical studies to preclinical studies. The focus on verbal memory is important because it is a cognitive function that has been shown to change with estrogen treatment and predict Alzheimer's disease risk but is not addressed by preclinical studies. Overall, we conclude that estrogen interacts with cholinergic and serotonergic systems to affect hippocampal and frontal cortical brain areas and thereby enhance memory, particularly at the retrieval stage.

Estrogens and age-related memory decline in rodents: what have we learned and where do we go from here?

The question of whether ovarian hormone therapy can prevent or reduce age-related memory decline in menopausal women has been the subject of much recent debate. Although numerous studies have demonstrated a beneficial effect of estrogen and/or progestin therapy for certain types of memory in menopausal women, recent clinical trials suggest that such therapy actually increases the risk of cognitive decline and dementia. Because rodent models have been frequently used to examine the effects of age and/or ovarian hormone deficiency on mnemonic function, rodent models of age-related hormone and memory decline may be useful in helping to resolve this issue. This review will focus on evidence suggesting that estradiol modulates memory, particularly hippocampal-dependent memory, in young and aging female rats and mice. Various factors affecting the mnemonic response to estradiol in aging females will be highlighted to illustrate the complications inherent to studies of estrogen therapy in aging females. Avenues for future development of estradiol-based therapies will also be discussed, and it is argued that an approach to drug development based on identifying the molecular mechanisms underlying estrogenic modulation of memory may lead to promising future treatments for reducing age-related mnemonic decline.

The interactive effect of the cholinergic system and acute ovarian suppression on the brain: an fMRI study

Recent evidence suggests that loss of ovarian function following ovariectomy is a risk factor for Alzheimer's disease (AD); however, the biological basis of this risk remains poorly understood. We carried out an fMRI study into the interaction between loss of ovarian function (after Gonadotropin Hormone Releasing Hormone agonist (GnRHa) treatment) and scopolamine (a cholinergic antagonist used to model the memory decline associated with aging and AD). Behaviorally, cholinergic depletion produced a deficit in verbal recognition performance in both GnRHa-treated women and wait list controls, but only GnRHa-treated women made more false positive errors with cholinergic depletion. Similarly, cholinergic depletion produced a decrease in activation in the left inferior frontal gyrus (LIFG; Brodmann area 45)--a brain region implicated in retrieving word meaning--in both groups, and activation in this area was further reduced following GnRHa treatment. These findings suggest biological mechanisms through which ovarian hormone suppression may interact with the cholinergic system and the LIFG. Furthermore, this interaction may provide a useful model to help explain reports of increased risk for cognitive decline and AD in women following ovariectomy.

Estrogen therapy affects right hemisphere functioning in postmenopausal women

It has been suggested that hormone therapy (HT) in postmenopausal women differentially affects verbal and visuo-spatial abilities which mainly rely on left hemisphere (LH) and right hemisphere (RH) functioning, respectively. Thus, it seems likely that HT-related effects on cognition are driven by associated hormonal changes and their impact on functional brain organization, and functional cerebral asymmetries (FCAs) in particular. The present study investigated HT-related effects on FCAs in sixty-seven postmenopausal women who received hormone therapy either with estrogen (E) alone (n=14), an E-gestagen combination (n=22) or without HT (control group, n=31). Saliva levels of free E and progesterone (P) were analyzed using chemiluminescence assays. FCAs were measured with the visual half-field (VHF) technique using a word matching and a figural comparison task. In agreement with previous results, a postmenopausal control group showed a left hemisphere (LH) advantage in the verbal task and a right hemisphere (RH) advantage in visuo-spatial processing. In contrast, both HT groups revealed significantly reduced FCAs in the figural comparison task as a result of an E-related decrease in RH performance. The findings suggest that E-therapy in postmenopausal women can affect visuo-spatial abilities by modulating the functional brain organization and RH functioning in particular.

Post-training progesterone dose-dependently enhances object, but not spatial, memory consolidation

The aim of this study was to determine if progesterone modulates object and spatial memory consolidation in young ovariectomized C57BL/6 mice. Object memory was tested in an object recognition task using 24- and 48-h delays. Spatial memory was tested in a 2-day version of the Morris water maze in which retention was tested 24 or 48 h after training. Immediately after training in each task, mice received a single intraperitoneal injection of vehicle or 5, 10, or 20mg/kg water-soluble progesterone. Mice were then tested 24 or 48 h later in the absence of circulating progesterone. Post-training injections of 10 and 20mg/kg progesterone enhanced object recognition, but not memory in the spatial water maze. These findings suggest that object memory consolidation in young female mice is more sensitive to the modulatory effects of progesterone than spatial memory consolidation, at least using the tasks, doses, and delays tested. As such, these findings may have important implications for the design of progesterone therapies intended to reduce age-related memory decline.

Estrogen and comprehension of metaphoric speech in women suffering from schizophrenia: results of a double-blind, placebo-controlled trial

OBJECTIVE

The effects of estrogen on comprehension of metaphoric speech, word fluency, and verbal ability were investigated in women suffering from schizophrenia. The issue of estrogen-dependent neuropsychological performance could be highly relevant because women with schizophrenia frequently suffer from hypoestrogenism.

METHOD

A placebo-controlled, double-blind, crossover study using 17beta-estradiol for replacement therapy and as an adjunct to a naturalistic maintenance antipsychotic treatment was carried out over a period of 8 months. Nineteen women (mean age = 38.0 years, SD = 9.9 years) with schizophrenia were included in the study. Comprehension of metaphoric speech was measured by a lexical decision paradigm, word fluency, and verbal ability by a paper-and-pencil test.

RESULTS

Significant improvement was seen for the activation of metaphoric meaning during estrogen treatment (P = .013); in contrast, no difference was found for the activation of concrete meaning under this condition. Verbal ability and word fluency did not improve under estrogen replacement therapy either.

CONCLUSIONS

This is the very first study based on estrogen intervention instead of the physiological hormone changes to examine the estrogen effects on neuropsychological performance in women with schizophrenia. In addition, it is the first time that the effect of estrogen on metaphoric speech comprehension was investigated in this context. While in a previous study estrogen therapy as adjunct to a naturalistic maintenance treatment with antipsychotics did not show an effect on psychopathology measured by a rating scale, a significant effect of estrogen on the comprehension of metaphoric speech and/or concretism, a main feature of schizophrenic thought and language disturbance, was found in the present study. Because the improvement of formal thought disorders and language disturbances is crucial for social integration of patients with schizophrenia, the results may have implications for the treatment of these individuals.

Cognitive function and brain structure in females with a history of adolescent-onset anorexia nervosa

OBJECTIVE

Abnormalities in cognitive function and brain structure have been reported in acutely ill adolescents with anorexia nervosa, but whether these abnormalities persist or are reversible in the context of weight restoration remains unclear. Brain structure and cognitive function in female subjects with adolescent-onset anorexia nervosa assessed at long-term follow-up were studied in comparison with healthy female subjects, and associations with clinical outcome were investigated.

PATIENTS AND METHODS

Sixty-six female subjects (aged 21.3 +/- 2.3 years) who had a diagnosis of adolescent-onset anorexia nervosa and treated 6.5 +/- 1.7 years earlier in a tertiary care hospital and 42 healthy female control subjects (aged 20.7 +/- 2.5 years) were assessed. All participants underwent a clinical examination, magnetic resonance brain scan, and cognitive evaluation. Clinical data were analyzed first as a function of weight recovery (n = 14, <85% ideal body weight; n = 52, >or=85% ideal body weight) and as a function of menstrual status (n = 18, absent/irregular menses; n = 29, oral contraceptive pill; n = 19, regular menses). Group comparisons were made across structural brain volumes and cognitive scores.

RESULTS

Compared with control subjects, participants with anorexia nervosa who remained at low weight had larger lateral ventricles. Twenty-four-hour urinary free-cortisol levels were positively correlated with volumes of the temporal horns of the lateral ventricles and negatively correlated with volumes of the hippocampi in clinical participants. Participants who were amenorrheic or had irregular menses showed significant cognitive deficits across a broad range of many domains.

CONCLUSIONS

Female subjects with adolescent-onset anorexia nervosa showed abnormal cognitive function and brain structure compared with healthy individuals despite an extended period since diagnosis. To our knowledge, this is the first study to report a specific relationship between menstrual function and cognitive function in this patient population. Possible mechanisms underlying neural and cognitive deficits with anorexia nervosa are discussed. Additional examination of the effects of estrogen on cognitive function in female subjects with anorexia nervosa is necessary.

Effects of menstrual cycle phase and oral contraceptive use on verbal memory

Surgical or pharmacological suppression of ovarian hormones leads to declines in verbal memory, and estrogen treatment reverses these deficits. In the current study, we investigated the effects of menstrual cycle phase and oral contraceptives on verbal memory, as measured by the California Verbal Learning Test, in two groups of premenopausal women - 16 naturally cycling women and 20 current users of estrogen-based oral contraceptives (OCs). Naturally cycling women were assessed twice - once during the early follicular phase (Days 2-4) and once during the midluteal phase (Days 20-22) of the menstrual cycle. OC users were tested on the same cycle days, corresponding to inactive and active pill phases, respectively. We predicted that naturally cycling women would show improved verbal memory during the midluteal phase, when estradiol levels are high, compared with the follicular phase, when estradiol levels are low. We also predicted that OC users, who show no change in endogenous estradiol across the cycle, would show no change in verbal memory. Contrary to predictions, naturally cycling women showed no changes in verbal memory across the cycle, whereas OC users showed enhanced memory during the active pill phase (p<.05). None of the secondary cognitive outcome measures varied with cycle phase or OC use including measures of visuospatial memory, verbal fluency, visuospatial abilities, and attention. Overall, these results suggest that verbal memory performance in premenopausal women varies across the cycle with OC use, but does not vary systematically with changes in endogenous estradiol.

Estrogen replacement therapy induces functional asymmetry on an odor memory/discrimination test

The secondary afferents of the olfactory system largely project to the ipsilateral cortex without synapsing in the thalamus, making unilateral olfactory testing a useful probe of ipsilateral hemispheric activity. In light of evidence that lateralized performance on some perceptual tasks may be influenced by estrogen, we assessed left:right nostril differences in two measures of olfactory function in 14 post-menopausal women receiving estrogen replacement therapy (ERT) and 48 post-menopausal women receiving no such therapy. Relative to women not taking ERT, those receiving ERT exhibited better performance in the left nostril and poorer performance in the right nostril on an odor memory/discrimination test. Similar laterality effects were not observed for an odor detection threshold test employing phenyl ethyl alcohol. These results suggest that estrogen influences the lateralization of an odor memory/discrimination task and that hormone replacement therapy in the menopause may be an excellent paradigm for understanding lateralizing effects of hormones on some sensory processes.