Estrogen therapy in postmenopausal women: effects on cognitive function and dementia

Tools for making correct decisions regarding hormone therapy. Part II. organ response and clinical applications

OBJECTIVE

To review existing scientific knowledge of the complicated and variable behavior and response to hormone therapy (HT) of different organs during aging, and to summarize long-term consequences on human health.

DESIGN

A MEDLINE computer search was performed to identify relevant articles.

RESULT(S)

Five body organs were evaluated. [1]. Physiologic aging of the bone has deleterious consequences on women's health and quality of life. Bone fractures could be attributed to the combination of estrogen depletion and osteoporosis, mechanisms of applied forces, and disturbed brain function, partially reversible by timely estrogen administration. [2]. Estrogen seems to have a profound neuroprotective effect. As physiologic aging of the brain is an unhealthy phenomenon, possible intervention is justified. The therapeutic time window seems crucial. [3]. The differentiation between response of a healthy or already damaged organ to sex hormones is the key factor to understanding the possible cardioprotective effects. [4]. Based on doubling time of tumor cells, intracrinology, epidemiological data on breast cancer, and behavior of breast cancer survivors in response to estrogen treatment, estrogen seems to be mainly a promoter and even a protector of breast cancer survivors. [5]. Colon cancer appears to be an estrogen-dependent tumor with a wide therapeutic window, as every report regardless of age and dose demonstrates protective effects.

CONCLUSION(S)

Knowledge of each organ's response to aging and sex hormone substitutions demonstrates that the organs could benefit from properly designed intervention. In the wake of the publication of the Women's Health Initiative study, which shocked the medical community, we suggest that the results be reevaluated according to the aforementioned principles, and that menopausal medicine could play an important role.

Antiaging Treatments Have Been Legally Prescribed for Approximately Thirty Years

There is an interesting divergence between the achievements of geriatrics and gerontology. On the one hand, during the last 30 years physicians in many developed countries have successfully prescribed several medicines to cure various symptoms of senescence. On the other hand, the influence of such medicines on human life span practically has not been studied. The most common of the relevant medicines are nootropic piracetam, gamma-aminobutyric acid (GABA), selegiline, Ginkgo biloba, pentoxifylline, cerebrolysin, solcoseryl, ergoloid, vinpocetin, sertraline, and estrogens, among others. Available data from human clinical practices and experimental animal studies indicate that treatments with these drugs improve learning, memory, brain metabolism, and capacity. Some of these drugs increase tolerance to various stresses such as oxygen deficit and exercise, stimulate the regeneration of neurons in the old brain, and speed up the performance of mental and physical tasks. This means that modern medicine already has "antiaging" treatments at its disposal. However, the influence of such treatments on the mean and maximal life span of humans, and on the age trajectory of a human survival curve has been poorly studied. The increase in human life expectancy at birth in the second half of the last century was mostly caused by the better survival at the old and oldest old rather than at the young ages. In parallel, the consumption of brain protective and regenerative drugs has been expanding in the elderly population. We provide evidence in support of the idea that the consumption of medicines exerting antiaging properties may contribute to the increase in human longevity.

Neuroprotective effect of genistein against beta amyloid-induced neurotoxicity

Estrogen is beneficial to patients with Alzheimer's disease (AD) but has a limited clinical use due to its proliferative and oncogenic effects on non-neuronal cells responsive to estrogen. In an attempt to find an estrogen substitute that retains the beneficial effects of estrogen with minimal side effects, we compared the neuroprotective and proliferative effects of genistein, a selective estrogen receptor (ER) beta-agonist, with those of estrogen. Genistein and 17beta-estradiol showed comparable levels of protection against Abeta-induced deaths of cultured SH-SY5Y human neuroblastoma cells, which were blocked by an estrogen receptor antagonist, ICI 182,780. On the other hand, 17beta-estradiol, but not genistein, induced proliferation of uterine endometrial cells. Our results suggest that genistein is a potential alternative to estrogen in the treatment of Alzheimer's disease.

Bioidentical hormone therapy: a review

OBJECTIVE

The terms "natural" or "bioidentical" hormone therapy (NHT) are used to describe hormone treatment with individually compounded recipes of certain steroids in various dosage forms, including dehydroepiandrosterone, pregnenolone, testosterone, progesterone, estrone, estradiol, and estriol. Based on the results of a person's salivary hormone levels, the final composition of the compounded dosage form is individualized to that specific person. Proponents claim that NHT is better tolerated than manufactured products. This paper is intended to review the concept of NHT and to determine whether there is sufficient scientific evidence to support its use.

DESIGN

A literature search was performed in Medline using the following MeSH terms and key words: drug combinations; progestational hormones; hormone replacement therapy; endometrium; estrogen replacement therapy; climacteric; menopause; estradiol; estrogens; progesterone; drug monitoring; and drug compounding. Current Contents, International Pharmaceutical Abstracts, Cochrane Database of Systematic Reviews, Lexis Nexis, Google, Medscape, MD Consult, and clinicaltrials.gov were searched with key words.

RESULTS

There are a few observational studies and clinical trials comparing conventional hormone therapy with bioidentical hormone therapy. Studies generally lacked adequate study design, including small sample sizes and comparison of inequivalent doses, to prove safety and efficacy. Little evidence was found to support individualized hormone dosing based upon saliva hormone concentrations.

CONCLUSION

Evidence suggests that, although individualized hormonal products may decrease some symptoms of menopause, it seems they have no proven advantage over conventional hormone therapies and their use is not supported by evidence regarding pharmacokinetics, safety, and efficacy.

In vivo effects of estrogen on human brain

Age-related brain disorders such as Alzheimer's disease (AD) are becoming increasingly prevalent. Estrogen replacement therapy (ERT) has shown potential both as a preventive measure and treatment for such disorders. Good evidence from basic science demonstrates that estrogen has multiple protective effects on neurons and neurotransmitter systems, and the effects of ERT can be demonstrated on the human brain using techniques such as functional neuroimaging. However, the evidence for estrogen's having a clinical role in the treatment and prevention of neuropsychiatric disorders is not well established. In this article we review research into the effects of estrogen on the human brain and we consider the role for ERT as a therapeutic tool.

The effect of short-term estradiol therapy on cognitive function in older men receiving hormonal suppression therapy for prostate cancer

OBJECTIVES

To determine the effect of estrogen (E) alone (without the influence of testosterone (T)) on cognitive function in older men, using 17-beta micronized estradiol versus placebo in older men rendered hypogonadal (low T and E) by treatment for prostate cancer.

DESIGN

Short-term double-blind, randomized, controlled trial.

SETTING

An outpatient General Clinical Research Center.

PARTICIPANTS

Twenty-seven community-dwelling men aged 65 and older receiving neoadjuvant or established therapy with luteinizing-hormone releasing-hormone agonists for treatment of prostate cancer enrolled in a short-term randomized, controlled trial of 17-beta micronized estradiol versus placebo on the effect on biochemical markers of bone turnover.

MEASUREMENTS

Hormone levels, including E, T, and sex hormone-binding globulin; standardized neurocognitive tests, including measures of sustained attention, executive function, and memory; and questionnaires to assess subjects' perception of cognitive deficits and symptoms of depression.

RESULTS

There were no significant differences between patients receiving E or placebo on 15 of 17 neurocognitive measures and no significant differences in self-reported cognitive deficits or number of depressive symptoms.

CONCLUSION

Although studies have suggested that E replacement therapy may improve cognitive function, most notably memory performance in postmenopausal woman, there was no evidence in the present study that the addition of short-term E therapy was more beneficial than placebo in tests of cognitive performance in hypogonadal men.

Ovarian hormones and cognition in the aged female rat: I. Long-term, but not short-term, ovariectomy enhances spatial performance

Although research suggests that ovariectomy (ovx) is detrimental to spatial cognition in young rats, little work has evaluated the cognitive effects of ovx in aged rats. The authors investigated the effects of ovx in aged rats using the water radial-arm maze. In Study 1, young rats and aged rats receiving ovx 1.5 months before testing outperformed aged rats receiving sham surgery or ovx 21 days before testing. In Study 2, young rats and aged rats receiving ovx 2.0 or 6.0 months before testing outperformed aged sham rats. Aged rats exhibited estradiol and elevated progesterone levels comparable to those of young rats. The findings suggest that 1.5-6.0 months, but not 21 days, of ovx improves spatial memory in aged rats. The hypothesis that long-term ovarian hormone loss is detrimental to spatial memory in aged rats was not supported. The authors hypothesize that removal of elevated progesterone levels is related to the ovx-induced cognitive enhancement.

Conjugated equine estrogens reverse the effects of aging on central and peripheral allopregnanolone and beta-endorphin levels in female rats

OBJECTIVE

To compare beta-endorphin and allopregnanolone levels and their response to a 2-week oral estrogen treatment with conjugated equine estrogens (CEE) in young ovariectomized (ovx) and in healthy aged female rats.

DESIGN

Prospective study.

SETTING

Animal laboratory in an academic environment.

ANIMAL(S)

Twenty-four young ovx and 24 healthy aged female Wistar rats were treated with CEE. Three 8-rat control groups (cycling, ovx, and aged rats) were also included.

INTERVENTION(S)

Treated rats underwent 14-day oral treatment with three doses of CEE: 0.1 mg/kg/day, 0.5 mg/kg/day, and 2 mg/kg/day.

MAIN OUTCOME MEASURE(S)

Cerebral and peripheral beta-endorphin and allopregnanolone levels.

RESULT(S)

Beta-endorphin levels were lower in aged vs. cycling and ovx control rats. In brain and serum allopregnanolone levels were lower in aged vs. cycling control rats, whereas in the adrenals they were higher in aged vs. cycling animals. In the hypothalamus and anterior pituitary allopregnanolone levels were lower in ovx vs. aged animals. In both ovx and aged animals, CEE treatment reverted the effects of ovariectomy and aging, in a dose-dependent manner.

CONCLUSION(S)

Aging is associated with a decrease in cerebral and peripheral beta-endorphin and allopregnanolone. In hypoestrogenic rats, CEE treatment restores allopregnanolone and beta-endorphin content; this indicates a role for these compounds as neuroendocrine mediators of the effects of estrogens.

Estrogens in the Nervous System: Mechanisms and Nonreproductive Functions

The past decade has witnessed a growing interest in estrogens and their activity in the central nervous system, which was originally believed to be restricted to the control of reproduction. It is now well accepted that estrogens modulate the activity of all types of neural cells through a multiplicity of mechanisms. Estrogens, by binding to two cognate receptors ERalpha and ERbeta, may interact with selected promoters to initiate the synthesis of target proteins. Alternatively, the hormone receptor complex may interfere with intracellular signaling at both cytoplasmic and nuclear levels. The generation of cellular and animal models, combined with clinical and epidemiological studies, has allowed us to appreciate the neurotrophic and neuroprotective effects of estrogens. These findings are of major interest because estradiol might become an important therapeutic agent to maintain neural functions during aging and in selected neural diseases.

Hormone Use and Cognitive Performance in Women of Advanced Age

OBJECTIVES

To explore the association between hormone replacement therapy (HRT) and cognitive performance in a group of elderly women (>/=75) using a battery of well-standardized neuropsychological instruments.

DESIGN

Equivalent samples from existing cohort.

SETTING

Healthcare provider organization.

PARTICIPANTS

All women enrolled were participants in an ongoing study of the association between HRT and the prevalence and incidence of dementia. Prescription records were used to establish HRT status. Fifty-eight users and 47 nonusers of HRT participated in this substudy.

MEASUREMENTS

Given previous reports that HRT has a positive effect on verbal memory, the California Verbal Learning Test and the Logical Memory Test were used as primary outcomes. A range of validated tests that assess other cognitive domains was also included.

RESULTS

There were no significant differences between users and nonusers of HRT on any cognitive measures.

CONCLUSION

Given equivalent groups of users and nonusers of HRT no support was found for the hypothesis that use of HRT improves cognitive performance in older women.

Median raphe mediates estrogenic effects to the hippocampus in female rats

Subcortical regions such as the medial septum-diagonal band of Broca and supramammillary area have been shown to mediate indirect oestrogenic effects on hippocampal morphology and function. Here, the role of the median raphe (MR), a serotonergic subcortical structure, is studied. To this end, 17beta-estradiol-filled 30-gauge cannulae were implanted into the MR of female ovariectomized rats; cholesterol-filled cannulae served as controls. After seven days, using unbiased electron microscopic stereological calculations and semiquantitative analysis, the spine synapse density and surface density of glial fibrillary acidic protein-positive astrocyte processes, respectively, were determined in the stratum radiatum of the CA1 region of the hippocampus. Changes in the serotonergic innervation of the hippocampal CA1 region were determined by immunohistochemistry and subsequent morphometric analysis. In the stratum radiatum of the CA1 region, local estradiol application into the MR resulted in a 47% increase in spine synapse density. Simultaneously, the density of glial fibrillary acidic protein-positive fibers decreased by 16%. The density of serotonin (5-HT) innervation of the strata lacunosum moleculare and radiatum of the CA1 region of the hippocampus was reduced in response to estradiol, as shown by a decrease in the length of fibers (27.6 and 48.3% decrease, respectively) and the number of large varicosities (32.5 and 38.8% decrease, respectively). These observations suggest a major role of the MR in mediating oestrogenic effects on the hippocampus and an involvement of the serotonergic system.

Aromatase: a neuroprotective enzyme

Estradiol, in addition to its participation in neuroendocrine regulation and sexual behavior, has neuroprotective properties. Different types of brain injury induce the expression of the enzyme aromatase in reactive astroglia. This enzyme catalyzes the conversion of testosterone and other C19 steroids to estradiol. Genetic or pharmacological inhibition of brain aromatase results in marked neurodegeneration after different forms of mild neurodegenerative stimuli that do not compromise neuronal survival under control conditions. Furthermore, aromatase mediates neuroprotective effects of precursors of estradiol such as pregnenolone, dehydroepiandrosterone (DHEA) and testosterone. These findings strongly suggest that local formation of estradiol in the brain is neuroprotective and that the induction of aromatase and the consecutive increase in the local production of estradiol are part of the program triggered by the neural tissue to cope with neurodegenerative insults. Aromatase may thus represent an important pharmacological target for therapies conducted to prevent aging-associated neurodegenerative disorders.

Alzheimer’s Disease and Vascular Dementia

This chapter explores the frequency with which dementing illnesses occur in populations, their distributions by personal characteristics, and what is known about their causes and potential protective factors. The primary focus is on the most common forms of dementia: Alzheimer's disease and vascular dementia. The chapter summarizes clinical and pathologic features of Alzheimer's disease and vascular dementia, and highlights recent theories of how risk factors affect brain reserve. With the evolution of the epidemiology of dementia from case-control studies to prospective cohort studies has come a new set of methodological challenges. These include identification of representative populations, enhancing subject participation and retention in studies, the need to include institutionalized as well as community-dwelling populations, the non-standardized use of cognitive tests to screen for dementia, and the complexities of the diagnostic process itself. Finally, the chapter summarizes risk and protective factors for disease expression, including cardiovascular risk factors, lifestyle factors, and factors that affect brain reserve.

Role of androgens in mild cognitive impairment and possible interventions during andropause

Mild cognitive impairment (MCI) is becoming fashionable as a diagnosis, representing a state of cognitive decline associated with negligible functional loss. MCI is important as it often precedes Alzheimer's disease (AD). Recognizing MCI may lead to preventive strategies that can delay the onset of AD. Many patients who transition into andropause report problems with their memory. There is strong evidence from basic sciences and epidemiological studies that both estrogens and androgens play a protective role in neurodegeneration. The evidence from small prospective clinical trials lends support to the role of hormones in improving cognitive function. The improvement in cognitive function with hormones is subtle and often not measurable on standard neuropsychological batteries. Patients have reported memory improvements in both declarative and procedural domains after being on hormonal replacement. Functional changes and vascular changes can be detected after hormonal replacement with more sophisticated imaging of the brain like PET scans. We hypothesize androgens and perhaps selective androgen receptor modulators as future treatment options for MCI in aging males.

Impact of the selective estrogen receptor modulator, raloxifene, on neuronal survival and outgrowth following toxic insults associated with aging and Alzheimer's disease

The current study investigated the estrogen agonist-antagonist properties of the selective estrogen receptor modulator, raloxifene (Ral), on neuroprotection and neuronal markers of memory function. Low concentrations of raloxifene significantly reduced basal markers of membrane damage and had no deleterious effect on neuronal survival. However, high concentrations of raloxifene (1000-5000 ng/ml) induced a significant increase in markers of membrane damage and a significant decrease in neuronal survival. At subtoxic concentrations, raloxifene induced significant neuroprotection against beta amyloid(25-35)-, hydrogen peroxide- and glutamate-induced toxicity. Results of analyses to determine whether raloxifene acted competitively or synergistically with 17 beta-estradiol revealed that a postmenopausal level of 17 beta-estradiol exerted a significantly greater increase in neuronal survival against beta-amyloid- and glutamate-induced toxicity compared to 50 ng/ml raloxifene. The combined presence of raloxifene and 17 beta-estradiol was significantly neuroprotective against beta amyloid(25-35)- and glutamate-induced excitotoxicity but was significantly lower than 17 beta-estradiol alone while not significantly different than raloxifene alone. Morphologic analyses demonstrated that raloxifene significantly increased neuronal outgrowth of hippocampal neurons within a narrow dose range that was blocked by a glutamate NMDA receptor antagonist. Raloxifene did not promote the outgrowth of basal forebrain or cortical neurons. Results of this study indicate that raloxifene exerted partial estrogen agonist action in the absence of 17 beta-estradiol whereas in the presence of 17 beta-estradiol, raloxifene exerted a mixed estrogen agonist-antagonist effect.

Turbulent times for hormone replacement therapy: is there a way out?

The long-awaited results of the large Women's Health Initiative (WHI) trial on the effects of combined estrogen-progestin hormone replacement therapy (HRT) in postmenopausal women show that the overall benefits are smaller than the risks. Herein I argue that many of the findings could be predicted from earlier observational studies. Although the WHI trial will rightly reverse the soaring HRT use of the last decades, there is unquestionably a future for HRT. A consensus is growing that postmenopausal women may be treated with HRT only when seeking help for disturbing symptoms of the ovarian hormone insufficiency syndrome, rather than be treated for menopause per se. The ovarian hormone insufficiency syndrome comprises conditions of estrogen and/or androgen insufficiency; at this time, the diagnosis of these clinical entities is based largely on symptomatology. Future research should disclose why the deprivation of ovarian hormones has a variable impact on women's functioning, and further trials ought to reveal effective and safe treatments for women suffering from this syndrome.

Estrogen decreases zinc transporter 3 expression and synaptic vesicle zinc levels in mouse brain

Previous studies suggest that female sex hormones modulate synaptic zinc levels, which may influence amyloid plaque formation and Alzheimer's disease progression. We examined the effects of ovariectomy and estrogen supplement on the levels of synaptic zinc and zinc transporter protein Znt3 in the brain. Ovariectomy was performed on 5-month-old mice, and 2 weeks later, pellets containing vehicle, low (0.18 mg/pellet), or high dose (0.72 mg) 17beta-estradiol were implanted. After 4 weeks, animals were decapitated, and blood and brain were collected for analysis. Blood analysis indicated that estrogen implants altered plasma estrogen levels in a dose-dependent manner. Analysis of brain tissue showed that ovariectomy raised hippocampal synaptic vesicle zinc levels, whereas estrogen replacement lowered these zinc levels. Western blots revealed that Znt3 levels in the brain were modulated in parallel with synaptic zinc levels, whereas no change was detected in the levels of Znt3 mRNA, as determined by Northern blot and reverse transcriptase-PCR analysis. However, mRNA levels of the delta subunit of adaptor protein complex (AP)-3, which modulates the level of Znt3 levels, were altered by estrogen depletion or replacement. These data demonstrate that estrogen alters the levels of Znt3 and synaptic vesicle zinc in female mice, probably through changing AP-3 delta expression. Since synaptic zinc may play a key role in neuronal death in acute brain injury as well as in plaque formation in Alzheimer's disease, and since estrogen may be beneficial in both conditions, our results may provide new insights into the effects of estrogen on the brain.

Cognitive function, fatigue, and menopausal symptoms in women receiving adjuvant chemotherapy for breast cancer

PURPOSE

There is evidence that cognitive dysfunction, fatigue, and menopausal symptoms may occur in women receiving adjuvant chemotherapy for breast cancer. Here, we determine their incidence and severity, and interrelationships between them and quality of life.

PATIENTS AND METHODS

In this study, 110 women receiving adjuvant chemotherapy each nominated a female relative, friend, or neighbor (matched by age) as a control; 100 eligible matched pairs were evaluated. Patients and controls completed the following assessments: the High-Sensitivity Cognitive Screen, and the Functional Assessment of Cancer Therapy-General (FACT-G) quality of life scale with subscales for fatigue (FACT-F) and endocrine symptoms (FACT-ES). They also performed tests of attention and reaction time.

RESULTS

Patients and controls were well matched for age and level of education. There was a higher incidence of moderate or severe cognitive impairment in the patient group (16% v 4%; P =.008). Patients experienced much more fatigue than controls (median FACT-F scores, 31 v 46; P <.0001) and more menopausal symptoms (median FACT-ES scores, 58 v 64; P <.0001). Self-reported quality of life of the patients was poorer than for controls, especially in physical and functional domains (median FACT-G scores, 77 v 93; P <.0001). There was strong correlation between fatigue, menopausal symptoms, and quality of life (P <.0001 for each pair), but none were significantly associated with the presence of cognitive dysfunction.

CONCLUSION

Adjuvant chemotherapy causes cognitive dysfunction, fatigue, and menopausal symptoms in women with breast cancer. Priority should be given to the study of strategies that might reduce these toxic effects.

The risk of dementia in relation to statins and other lipid lowering agents

Recent epidemiological reports suggest that statins, and possibly other lipid lowering agents, might be protective for Alzheimer disease, and for other types of dementia. Importantly, however, epidemiological reports of this type are susceptible to indication bias, i.e. people who elect to take lipid-lowering agents might be healthier than those who do not, so that it may be these other health factors which explain their lower risk of dementia. Limited clinical trials data support the notion that statins, in particular, have important effects on cerebral cholesterol metabolism, but the link to clinical effects in dementia has yet to be established, and the mechanisms by which lipid lowering agents might confer protective effects is unclear. Dedicated clinical trials are now under way, and their results are awaited with great interest.

Postmenopausal hormone therapy: a concise guide to therapeutic uses, formulations, risks, and alternatives

Postmenopausal hormone replacement therapy is helpful in relieving menopausal vasomotor symptoms and vaginal atrophy and can prevent osteoporosis; however, attendant risks include breast cancer, thromboembolism, gallbladder disease, stroke, CHD, dementia, and hypertriglyceridemia. Decision making must weigh these risks and benefits and also include potential benefits on mood, colorectal cancer prevention, and hip fracture reduction. Some areas, such as ovarian cancer risk and the impact of combination estrogen-progestin versus unopposed estrogen on risk, remain unclear. The physician and patient need to carefully assess, discuss, and monitor the individual's symptoms and risks when considering HT use. For those with contraindications or concerns about HT, there are alternative therapies of variable efficacy for vasomotor symptoms and vaginal atrophy.

Clinical pharmacology of anti-Alzheimer drugs

Alzheimer's disease (AD) is a chronic neurodegenerative disorder characterized by a progressive loss of cognitive and functional abilities, associated with various degrees of behavioural disturbances, with a devastating impact on public health and on the whole society. Slowing of cognitive impairment, duration of disease, self-sufficiency and behavioural disturbances represent the best outcomes of the pharmacologic therapy. Cholinesterase inhibitors (ChE-I) have been shown to be effective in the treatment of the cognitive, behavioural, and functional deficits of AD. In addition to ChE-I, a number of studies have been carried out to investigate the possible use of other compounds and pharmacologic strategies; more compounds, postsynaptic muscarinic and nicotinic receptor agonists, are under investigation. The standard suggested care for pharmacologic management of the cognitive and functional disabilities of AD at present consists of treatment with ChE-I. Practice recommendations and treatment guidelines are derived from clinical trials.

Current concepts in the prevention of Alzheimer's disease

Alzheimer's disease represents a significant challenge to the aging population. Since most estimates suggest that AD has a multifactorial etiology, the challenge to find preventative approaches is particularly great. With the aging of the population and the very high incidence from the eighth decade on, the challenge is further enhanced by the need to think of relatively safe interventions given the relative frailty of this elderly population. The need to find safe treatments, or ones with well-understood safety profiles, has led to the examination of known agents for potential dementia-preventing properties. Data supporting these interventions comes from observational studies, laboratory analyses, and clinical trials. Potential mechanisms for prevention of AD include anti-inflammatory and antioxidant approaches. Modulation of risk factors associated with cardiac disease may also reduce the risk of AD. Known agents have been examined for their potential to modify amyloid pathology. Trial designs to address prevention of AD include both primary and secondary prevention studies as well designs to assess slowing disease progression. Information can also be gathered when dementia evaluation is added to ongoing studies. As results from these studies becoming available, we will be able to refine our approach to managing this disease.

The combination of a novel selective estrogen receptor modulator with an estrogen protects the mammary gland and uterus in a rodent model: the future of postmenopausal women's health?

The Women's Health Initiative Study and other reports have created major uncertainty among postmenopausal women and physicians concerning hormone replacement therapy. We have thus investigated the possibility of replacing the progestin in hormone replacement therapy by a novel selective estrogen receptor (ER) modulator having potent and pure antiestrogenic activity in the mammary gland and uterus. As measured by changes in histology and Cdc47 labeling in the rat model, the present study shows that the stimulatory effect of estradiol in the mammary gland and uterus is efficiently blocked by simultaneous administration of the novel selective ER modulator EM-652, but bone mineral density is preserved and serum cholesterol is decreased. After the administration of 14C-labeled EM-652, we observed that there is no detectable radioactivity in the brain. Moreover, ER alpha immunoreactivity remained constant in the hypothalamus after EM-652 treatment, whereas ER alpha became almost undetectable in the mammary gland and uterus. The present data show the poor or absent access of EM-652 to the brain, whereas the effects of estrogens are efficiently neutralized in the mammary gland and uterus. Such data support the exciting possibility of a novel approach that could meet most of the needs of women's health at menopause, namely control of hot flushes and prevention of breast, uterine, and ovarian cancer as well as osteoporosis and potentially helping brain function and preventing Alzheimer's disease with no identifiable risk or negative effect.

Estrogen increases the number of spinophilin-immunoreactive spines in the hippocampus of young and aged female rhesus monkeys

It is well documented that estrogen increases dendritic spine density in CA1 pyramidal cells of young female rats. However, this effect is attenuated in aged rats. We report here a quantitative analysis of estrogen effects on hippocampal spine number as visualized with antispinophilin in young (6-8 years old) and aged (19-23 years old) female rhesus monkeys, a species with a pattern of female endocrine senescence comparable to that of humans. Monkeys were ovariectomized and administered either vehicle or estradiol cypionate 3 months postovariectomy, followed by an additional dose 3 weeks later, with perfusion 24 hours after the last estrogen treatment. Immunolocalization of spinophilin, a spine-associated protein, was used for quantitative stereologic analyses of total spinophilin-immunoreactive spine numbers in CA1 stratum radiatum and the inner and outer molecular layers of dentate gyrus. In both young and aged female monkeys, the estrogen-treated groups had an increase in spinophilin-immunoreactive spines (37% in young, P <.005; 35% in aged, P <.05) compared with the untreated groups that amounted to more than 1 billion additional immunoreactive spines. The young group also showed a trend toward an estrogen-induced increase in immunoreactive spines in the dentate gyrus outer molecular layer, but this effect was not statistically significant (P =.097). We conclude that spine number in the rhesus monkey hippocampus is highly responsive to estrogen, yet, unlike the female rat, aged female rhesus monkeys retain the capacity for spine induction in response to estrogen. These data have important implications for cognitive effects of estrogen replacement in postmenopausal women and demonstrate that an estrogen replacement protocol that mimics normal physiological cycles with timed, intermittent peaks can have profound neurobiological effects.

Estradiol selectively affects processing of conspecifics' faces in female rhesus monkeys

Estrogen deficiency following ovariectomy or menopause increases the risk of developing diseases such as osteoporosis and may also lead to memory impairment. Although estrogen replacement therapy (ERT) alleviates many symptoms associated with estrogen loss, it is not clear whether it also benefits cognitive function. The effect of estrogens upon cognition can best be studied in an animal model of human menopause, in which estrogen levels can be experimentally manipulated. Six young ovariectomized female rhesus monkeys (6-9 years old) were tested on a battery of touchscreen-based cognitive tasks, including the Matching-to-Sample (MTS) task with mixed delays and the spatial, object, and face conditions of the Delayed Recognition Span Test (DRST). Monkeys were tested 5 days a week, one task per week, for a total of 8 months, while undergoing treatments with placebo and ethinyl estradiol (EE2) in alternating 28-days blocks. Blood samples were collected to verify EE2 levels. We also observed the monkeys by video monitor during test sessions and recorded locomotor activity and response topology. Performance on the face-DRST, a task that involved selecting the new face in an increasing array of rhesus monkey faces, was impaired by EE2 treatment, as compared to placebo. Other tasks were unaffected by EE2. There was no clear evidence of EE2 effects upon motor activity or anxiety. In order to test the reliability of our findings, we conducted an additional experiment in which the monkeys were again given the face-DRST with different categories of face stimuli for 4 months, while receiving placebo and EE2 in alternating 7-days blocks. They performed each task 4-5 days/week for 4 weeks with (1) the same rhesus monkey faces as in the first experiment, (2) human faces, (3) chimpanzee faces, and (4) novel rhesus monkey faces. Face-DRST performance did not vary as a function of treatment when human or chimpanzee faces were used as stimuli. In contrast, periods of EE2 treatment were associated with a lower performance for both sets of rhesus monkey faces. These findings suggest that EE2 treatment has a detrimental effect on processing faces of conspecifics by female rhesus monkeys. We speculate that estrogens may produce this effect by enhancing emotional reactivity to socially relevant stimuli.

Novel estrogen receptor ligands based on an anthranylaldoxime structure: role of the phenol-type pseudocycle in the binding process

The 3,4-diphenylsalicylaldoxime system 1 is an estrogen receptor (ER) ligand of unusual structure, having a hydrogen-bonded pseudocyclic A'-ring in place of the paradigmatic phenolic A-ring that is characteristic of most estrogens. We have investigated the role played by the pseudocycle A' in binding to the ER by preparing 3,4-diphenylbenzaldoxime (4), a compound that completely lacks this ring but still preserves all of the other features of the original molecule 1, as well as a series of 3,4-diphenylanthranylaldoximes (5a-c) in which the nature of the heteroatom participating in the formation of pseudoring A' has been changed from an oxygen (1) to a nitrogen that is either unsubstituted (5a) or substituted with small alkyl groups (a methyl in 5b, or an ethyl in 5c). The importance of hydrogen-bonded pseudocycle A' in the binding process was confirmed by the fact that benzaldoxime 4 showed a greatly reduced binding affinity compared to salicylaldoxime 1. Moreover, the binding affinity improved considerably when the A'-ring contained either an unsubstituted nitrogen (5a) or an N-Me group (5b). On the other hand, the N-Et-substituted anthranyl derivative 5c showed a marked drop in binding affinity. Molecular modeling docking studies on ERalpha confirmed that compounds 5a and 5b fit nicely in the ligand binding pocket, with an especially comfortable fit for the N-Me group of 5b in a small hydrophobic pocket surrounded by nonpolar residues. The limited size of this pocket does not allow accommodation of N-substituents larger than a methyl group, which is consistent with the low binding affinity of the N-Et compound 5c.

Steroid hormones and neurosteroids in normal and pathological aging of the nervous system

Without medical progress, dementing diseases such as Alzheimer's disease will become one of the main causes of disability. Preventing or delaying them has thus become a real challenge for biomedical research. Steroids offer interesting therapeutical opportunities for promoting successful aging because of their pleiotropic effects in the nervous system: they regulate main neurotransmitter systems, promote the viability of neurons, play an important role in myelination and influence cognitive processes, in particular learning and memory. Preclinical research has provided evidence that the normally aging nervous system maintains some capacity for regeneration and that age-dependent changes in the nervous system and cognitive dysfunctions can be reversed to some extent by the administration of steroids. The aging nervous system also remains sensitive to the neuroprotective effects of steroids. In contrast to the large number of studies documenting beneficial effects of steroids on the nervous system in young and aged animals, the results from hormone replacement studies in the elderly are so far not conclusive. There is also little information concerning changes of steroid levels in the aging human brain. As steroids present in nervous tissues originate from the endocrine glands (steroid hormones) and from local synthesis (neurosteroids), changes in blood levels of steroids with age do not necessarily reflect changes in their brain levels. There is indeed strong evidence that neurosteroids are also synthesized in human brain and peripheral nerves. The development of a very sensitive and precise method for the analysis of steroids by gas chromatography/mass spectrometry (GC/MS) offers new possibilities for the study of neurosteroids. The concentrations of a range of neurosteroids have recently been measured in various brain regions of aged Alzheimer's disease patients and aged non-demented controls by GC/MS, providing reference values. In Alzheimer's patients, there was a general trend toward lower levels of neurosteroids in different brain regions, and neurosteroid levels were negatively correlated with two biochemical markers of Alzheimer's disease, the phosphorylated tau protein and the beta-amyloid peptides. The metabolism of dehydroepiandrosterone has also been analyzed for the first time in the aging brain from Alzheimer patients and non-demented controls. The conversion of dehydroepiandrosterone to Delta5-androstene-3beta,17beta-diol and to 7alpha-OH-dehydroepiandrosterone occurred in frontal cortex, hippocampus, amygdala, cerebellum and striatum of both Alzheimer's patients and controls. The formation of these metabolites within distinct brain regions negatively correlated with the density of beta-amyloid deposits.

Better oral reading and short-term memory in midlife, postmenopausal women taking estrogen

OBJECTIVE

Considerable controversy surrounds the issue of whether estrogen influences cognitive function in postmenopausal women, and the results are far from consistent. For the most part, the cognitive processes studied have involved memory; to our knowledge, no previous studies have specifically examined the effects of estrogen on women's reading ability.

DESIGN

To investigate reading and short-term memory in postmenopausal women treated with conjugated equine estrogens, we carried out a randomized, double-blind, placebo-controlled trial of 21 days in 60 midlife, postmenopausal women aged 32.8 to 64.9 years (mean 51.2 years, SD 5.0 years). Women were evaluated for oral reading measured by Gray Oral Reading Tests (third edition) and for verbal memory using immediate and delayed recall on the Logical Memory and Paired Associate Learning subtests of the Wechsler Memory Scale and by a Sentence Span task.

RESULTS

The group receiving daily treatment with conjugated equine estrogens (Premarin, 1.25 mg; Wyeth-Ayerst Labs, Philadelphia, PA, USA) showed better oral reading and verbal memory performance than the placebo group.

CONCLUSION

Estrogen may have positive effects on oral reading and verbal memory in midlife, postmenopausal women.

Preliminary evidence that estrogen protects against age-related hippocampal atrophy

Few studies have examined gender differences in hippocampal volumes, and the potential effect of estrogen on these measures has not been well studied. We used MRI to measure hippocampal volumes in elderly Mexican American men and women subjects in order to determine if there were gender differences and if estrogen replacement therapy (ERT) had an effect on hippocampal volume in postmenopausal women. MRI measures of hippocampal volumes (normalized to intracranial volume) were compared in 59 women and 38 men. Further comparisons were made between men subjects, women subjects taking ERT, and women subjects not taking ERT. There were no significant effects of gender on normalized hippocampal volumes. However, women subjects taking ERT had larger right hippocampal volumes than women subjects not taking ERT and larger anterior hippocampal volumes than men subjects and women subjects not taking ERT. These findings suggest a neuroprotective effect of estrogen.

Assessment and treatment of hot flushes and menopausal mood disturbance

More than 1 million women are expected to reach menopause each year, many of whom will experience hot flushes and other neuropsychological symptoms that may diminish their quality of life. Hot flushes are the core symptoms that reflect the brain's response to the changing hormonal milieu of the menopause transition, particularly to the rapidly fluctuating and falling levels of estradiol. The physical symptoms of hot flushes and the associated changes in sleep, mood, and cognition will lead many women to seek medical care. It is critical to understand the interrelationship of hot flushes and other neuropsychological symptoms of the menopause transition so that treatment priorities can be established. For example, if sleep disruption explains most daytime neuropsychological problems in women with hot flushes, treating insomnia should be considered a priority. Alternatively, mood, cognition, and quality of life may be disturbed independent of sleep problems. In such a situation, each symptom should be evaluated separately from any assessment of sleep. As recent data from the WHI establish the risks of long-term HRT use, concern about using HRT, even as a short-term intervention, has increased substantially. Although HRT remains the first-line treatment for hot flushes, the WHI findings have drawn attention to nonhormonal treatments of hot flushes and other menopausal symptoms. Growing evidence to support the efficacy of serotonergic antidepressants and other psychoactive medications in the treatment for hot flushes suggests that nonhormonal interventions will prove important alternatives to HRT. As further evidence of the benefits of psychoactive medications for menopausal symptoms is established, the choice between using hormonal and nonhormonal therapies for management of menopausal symptoms will continue to evolve.

The effects of hormone therapy on cognition in breast cancer

The use of hormonal therapies for the treatment of breast cancer is common, yet few studies have examined the possible cognitive effects. Several regions of the brain, important in memory and cognition, are rich in oestrogen receptors. As a result, the long-term use of anti-oestrogens may have potential consequences for cognition. This project aims to establish whether significant cognitive deficit exists in women receiving hormone therapy for breast cancer and to develop a cognitive package that is sensitive to the potential effects of oestrogen deficiency on cognition. Cognitive assessments measured a range of memory and attention functions in patient and control groups to identify whether cognitive impairment, if apparent, occurs at a widespread or function specific level. Ninety-four patients from the anastrozole, tamoxifen and combined (ATAC) trial and 35 non-cancer controls were assessed. Groups did not differ significantly in age or estimated full-scale intelligence. The patient group did not differ from controls on measures of working memory, attention and visual memory but was significantly impaired compared to the control group on measures of verbal memory (P=0.026) and processing speed (P=0.032). Cognitive performance in the patient group was not significantly related to length of time on trial or measures of psychological morbidity. As more and more hormonal agents are used in clinical trials of both adjuvant and preventive settings it is of vital importance that any potentially deleterious effects on cognitive function are measured adequately. Preliminary results from this study suggest that anti-oestrogen therapy may cause a specific deficit in verbal memory that corroborates the links between oestrogen levels and verbal memory often reported in studies of the cognitive benefits of hormone replacement therapy.

Ovarian steroids reduce apoptosis induced by trophic insufficiency in nerve growth factor-differentiated PC12 cells and axotomized rat facial motoneurons

Previous studies have demonstrated that ovarian steroids exert neuroprotective effects in a variety of in vitro and in vivo systems. The mechanisms underlying these effects remain poorly understood. In the present study, the neuroprotective effects of estradiol (E(2)) and progesterone (P) were examined in two models of apoptosis induced by growth factor insufficiency: partially nerve growth factor (NGF)-differentiated PC12 cells, after serum and NGF withdrawal; and axotomized immature rat facial motor motoneurons. E(2) and P both increased the survival of trophically withdrawn NGF-differentiated PC12 cells, at physiologically relevant concentrations. However, neither steroid had a significant effect on the survival of PC12 cells that had not been NGF treated. Exposure to NGF had no effect on the expression of estrogen receptor (ER)beta, but markedly increased the levels of ERalpha and altered the expression of the progesterone receptor (PR) from predominantly PR-B in NGF naive cells, to predominantly PR-A after NGF. The survival promoting effects of E(2) and P were blocked by the specific steroid receptor antagonists Faslodex (ICI 182780) and onapristone (ZK98299), respectively. Inhibitors of RNA (actinomycin D) or protein (cycloheximide) synthesis also abrogated the protective effects of both steroids. In immature rats, E(2) and P both significantly increased the numbers of surviving facial motor neurons at 21 days after axotomy. These data demonstrate significant protective effects of E(2) and P in two well-characterized models of apoptosis induced by trophic withdrawal and suggest that, at least in PC12 cells, the effects of the steroids are mediated via interaction with nuclear steroid receptor systems. The lack of steroid responsiveness in NGF-naive PC12 cells despite the presence of abundant ERbeta and PR-B are consistent with the view that ERalpha and PR-A may be particularly important as mediators of the neuroprotective effects of their corresponding hormonal ligands.

Estrogen receptor-alpha mediates the brain antiinflammatory activity of estradiol

Beyond the key role in reproductive and cognitive functions, estrogens have been shown to protect against neurodegeneration associated with acute and chronic injuries of the adult brain. Current hypotheses reconcile this activity with a direct effect of 17beta-estradiol (E2) on neurons. Here we demonstrate that brain macrophages are also involved in E2 action on the brain. Systemic administration of hormone prevents, in a time- and dose-dependent manner, the activation of microglia and the recruitment of peripheral monocytes induced by intraventricular injection of lipopolysaccharide. This effect occurs by limiting the expression of neuroinflammatory mediators, such as the matrix metalloproteinase 9 and lysosomal enzymes and complement C3 receptor, as well as by preventing morphological changes occurring in microglia during the inflammatory response. By injecting lipopolysaccharide in estrogen receptor (ER)-null mouse brains, we demonstrate that hormone action is mediated by activation of ERalpha but not of ERbeta. The specific role of ERalpha is further confirmed by comparing the effects of ERs on the matrix metalloproteinase 9 promoter activity in transient transfection assays. Finally, we report that genetic ablation of ERalpha is associated with a spontaneous reactive phenotype of microglia in specific brain regions of adult ERalpha-null mice. Altogether, these results reveal a previously undescribed function for E2 in brain and provide a mechanism for its beneficial activity on neuroinflammatory pathologies. They also underline the key role of ERalpha in brain macrophage reactivity and hint toward the usefulness of ERalpha-specific drugs in hormone replacement therapy of inflammatory diseases.

Sex differences in episodic memory: minimal influence of estradiol

Sex differences exist for several cognitive tasks and estrogen has been suggested to influence these differences. Eighteen men and 18 women were matched on age and estradiol level. Potential sex differences were assessed in episodic memory, semantic memory, verbal fluency, problem solving, and visuospatial ability. Significant sex differences, favoring women, were found for tasks assessing episodic memory. Correlations between estradiol level and cognitive performance were significant for face recognition in females. Since sex differences remained in verbal episodic memory tasks and face recognition despite matched levels of estradiol, circulating estradiol does not appear to be of paramount consequence for observed sex differences in episodic memory.

Estrogen and neurodegeneration

Although estrogen is best known for its effects on the maturation and differentiation of the primary and secondary sex organs, increasing evidence suggests that its influence extends beyond this system, and its activity in the CNS may initiate, or influence our susceptibility to neurodegenerative decline. Estrogen has been proposed to act as a neuroprotectant at several levels, and it is probable that deprivation of estrogen as a result of menopause exposes the aging or diseased brain to several insults. In addition, estrogen deprivation is likely to initiate or enhance degenerative changes caused by oxidative stress, and to reduce the brain's ability to maintain synaptic connectivity and cholinergic integrity leading to the cognitive decline seen in aged and disease-afflicted individuals.

An estrogen replacement therapy containing nine synthetic plant-based conjugated estrogens promotes neuronal survival

Epidemiological data from retrospective and case-control studies have indicated that estrogen replacement therapy can decrease the risk of developing Alzheimer's disease. In addition, estrogen replacement therapy has been found to promote neuronal survival both in vivo and in vitro. We have shown that conjugated equine estrogens (CEE), containing 238 different molecules composed of estrogens, progestins, and androgens, exerted neurotrophic and neuroprotective effects in cultured neurons. In the current study, we sought to determine whether a steroidal formulation of nine synthetic conjugated estrogens (SCE) chemically derived from soybean and yam extracts is as effective as the complex multisteroidal formulation of CEE. Analyses of the neuroprotective efficacy indicate that SCE exhibited significant neuroprotection against beta amyloid, hydrogen peroxide, and glutamate-induced toxicity in cultured hippocampal neurons. Indices of neuroprotection included an increase in neuronal survival, a decrease in neurotoxin-induced lactate dehydrogenase release, and a reduction in neurotoxin-induced apoptotic cell death. Furthermore, SCE was found to attenuate excitotoxic glutamate-induced [Ca2+]i rise. Quantitative analyses indicate that the neuroprotective efficacy of SCE was comparable to that of the multisteroidal CEE formulation. Data derived from these investigations predict that SCE could exert neuroprotective effects comparable to CEE in vivo and therefore could reduce the risk of Alzheimer's disease in postmenopausal women.

Early Intervention Is Key to Successful Management of Alzheimer Disease

Because of the huge healthcare burden associated with Alzheimer disease (AD) and the increased lifespan in many industrialized countries, the costs associated with AD are expected to reach astronomical proportions in the next 50 years. Diagnosis, treatment and follow-up of AD patients from the earliest stage possible will reduce healthcare costs and increase quality of life. Indeed, progress in our clinical knowledge of AD has led to more reliable diagnostic criteria and diagnostic accuracy, and research efforts are expanding to uncover the earliest manifestations and even the presymptomatic phases of the disease. The initiating and propagating pathologic processes and the anatomic location of the earliest changes will become new targets of research and therapeutic development. The proposed precursor to AD, mild cognitive impairment, is currently under investigation as a possible therapeutic starting point. This paper reviews our current understanding of the early pathology and clinical manifestations associated with mild cognitive impairment and early AD. A discussion of the latest diagnostic techniques as well as promising therapeutic targets for early intervention also will be included.

Alcohol, estrogen replacement therapy, and visuospatial processes in postmenopausal women

BACKGROUND

Studies suggest that moderate drinking may benefit cognition and the effect may favor women. This study investigated effects of moderate drinking on visuospatial functioning in postmenopausal women. Visuospatial processes are sensitive to alcohol abuse and are thought to be sensitive to hormonal fluctuations. Three questions were posed in order to: explore visuospatial processes in moderate-drinking and abstaining postmenopausal women, assess visuospatial differences in women using no estrogen replacement therapy (No-ERT), ERT alone (ERT-only), and ERT with progestin (ERT+Pro), and identify alcohol/ERT interactions associated with visuospatial performance.

METHODS

Two hundred fourteen postmenopausal women participated (75 No-ERT; 63 ERT-only; 76 ERT+Pro. All were moderate drinkers or teetotalers and all received the Block Design test from the Wechsler Adult Intelligence Scale-Revised. A raw score was calculated and progress at 30-sec intervals was assessed.

RESULTS

ANOVA revealed an alcohol main effect [F(3,202) = 4.74; p < 0.004] on 60- to 120-sec change scores. Teetotalers had significantly smaller change scores (less improvement) compared with all levels of drinkers. ANOVA on design 9 (the most difficult trial) revealed an ERT main effect [F(3,202) = 4.37; p < 0.02]. ERT nonusers scored significantly lower than ERT-only and ERT+Pro groups. A design 9 trend toward an alcohol x ERT interaction was noted [F(6,202) = 1.93; p < 0.08], and a design 9 time x alcohol interaction was revealed [F(6,404) = 2.65; p < 0.02].

CONCLUSIONS

These data suggest that moderate drinking may be positively associated with visuospatial processes in postmenopausal women. They also suggest that ERT, alone and with progestin, is positively associated with visuospatial processes, but only when the task is difficult. These findings support Kaplan's assertion that subtle performance deficits may not be detectible with traditional endpoint measures. A provocative alcohol x ERT trend suggests that alcohol consumption should be considered in studies of ERT effects on cognitive ability.

Menopause rather than estrogen modifies plasma homocysteine levels

OBJECTIVES

To investigate the effects of transdermal estrogen replacement therapy (ERT) on plasma homocysteine levels in postmenopausal women who underwent total hysterectomy with bilateral oophorectomy.

METHODS

In two-phase open longitudinal prospective study we compared 28 premenopausal women and 35 healthy postmenopausal patients to evaluate the effect of transdermal estrogen treatment (TTS 50 twice-weekly) on plasma homocysteine levels after 6 and 12 months of therapy.

RESULTS

The study showed statistically relevant differences (P<0.05) in baseline plasma homocysteine concentration between the patients in premenopausal and in postmenopausal status. No difference in the plasma homocysteine levels was observed after 6 and 12 months of ERT on postmenopausal patients.

CONCLUSIONS

Surgically postmenopausal women have higher plasma homocysteine concentrations than premenopausal women, but transdermal estrogen treatment for 12 months in postmenopausal women does not modify homocysteine levels.

Improved cognitive function in postmenopausal women after 12 weeks of consumption of a soya extract containing isoflavones

We previously reported that a high soya diet improved memory and frontal lobe function in young volunteers, and since soya isoflavones are agonists at oestrogen receptors, they may improve these functions in postmenopausal women. Thirty-three postmenopausal women (50-65 years) not receiving conventional hormone replacement therapy (HRT) were randomly allocated in a double-blind parallel study to receive a soya supplement (60 mg total isoflavone equivalents/day) or placebo for 12 weeks. They received a battery of cognitive tests and completed analogue rating scales of mood and sleepiness, and a menopausal symptoms questionnaire before the start of treatment and then after 12 weeks of treatment. Those receiving the isoflavone supplement showed significantly greater improvements in recall of pictures and in a sustained attention task. The groups did not differ in their ability to learn rules, but the isoflavone supplement group showed significantly greater improvements in learning rule reversals. They also showed significantly greater improvement in a planning task. There was no effect of treatment on menopausal symptoms, self-ratings of mood, bodily symptoms or sleepiness. Thus, significant cognitive improvements in postmenopausal women can be gained from 12 weeks of consumption of a supplement containing soya isoflavones that are independent of any changes in menopausal symptoms, mood or sleepiness.

Testosterone, but not nonaromatizable dihydrotestosterone, improves working memory and alters nerve growth factor levels in aged male rats

Recent studies have suggested that testosterone levels are lower in men with Alzheimer's disease and that testosterone treatment improves cognition in older men. Since testosterone can be aromatized to estrogen, testosterone's effects could be due to conversion into estrogen. We treated aged male rats with either testosterone or dihydrotestosterone (DHT), the latter of which is not aromatized to estrogen, in order to determine whether these treatments improve spatial working and reference memory as assessed in the water radial arm maze. We also tested whether such effects are related to beta-amyloid levels in the hippocampus or neurotrophin levels in the hippocampus, entorhinal cortex, frontal cortex, or striatum. Aged rats made more errors than young rats on all memory measures. Testosterone, but not DHT, improved working memory and decreased hippocampal NGF protein in aged rats, while having no effect on beta-amyloid. However, higher beta-amyloid levels were correlated with poorer working memory performance in young rats. Neurotrophin levels in entorhinal cortex were positively correlated with errors for all memory measures in androgen-treated rats. Similar to findings in human studies, in our study androgen treatment lowered circulating estradiol levels in aged rats, suggesting that androgen treatment exerts feedback to the hypothalamic pituitary axis and that conversion to estrogen may not be the underlying biological mechanism of testosterone's effects on memory and growth factor levels. The ratio of estradiol to testosterone, or the actions of the aromatase enzyme itself, may be responsible for the observed effects. These data support the hypothesis that testosterone therapy in aging men may provide positive effects on cognition and that neural regions that are linked to cognition, such as the hippocampus and/or entorhinal cortex, may be involved in such effects.

Treatment of mild cognitive impairment: rationale, present and future strategies

Mild cognitive impairment (MCI) is a condition with a high conversion rate to Alzheimer's disease (AD), which justifies early diagnostic and therapeutic interventions. At the moment, treatment strategies for AD could be extrapolated to interventional strategies in MCI. This article reviews currently available symptomatic treatments with acetylcholinesterase inhibitors, putative treatments such as antiglutamatergic drugs, nootropics, antioxidants, anti-inflammatory drugs and still controversial estrogen replacement therapy, and visionary treatments targeting neuropathological substrates of the disease, such as amyloid production and aggregation, phosphorylation of tau, formation of neurofibrillary tangles and apoptosis. Findings from epidemiological studies have expanded our knowledge on risk as well as possible neuroprotective factors and given means to develop preventive strategies with antihyperlipidaemic drugs such as statins. A wide range of suggested treatments and their possible combinations necessitate their efficacy assessment in well-designed randomized clinical trials where the crucial prerequisites are selection of the treatment population and definitions of outcome measures. Prevention and disease-modifying strategies are raising ethical questions because interventions are focused on non-diseased elderly at risk, which means that emphasis should be not only on efficacy but also on long-term safety.

Effect of soy-derived isoflavones on hot flushes, endometrial thickness, and the pulsatility index of the uterine and cerebral arteries

OBJECTIVE

To determine the effect of soy-derived isoflavones on hot flushes, endometrial thickness, and the vascular reactivity of uterine and cerebral arteries.

DESIGN

Double-blind, randomized, placebo-controlled trial.

SETTING

Healthy volunteers in an academic research environment.

PATIENT(S)

Sixty-two postmenopausal women aged 45-60 years attending the Outpatient Menopause Clinic of our gynecological departments.

INTERVENTION(S)

The patients were administered 72 mg of soy-derived isoflavones or placebo under double-blind conditions. The daily number of hot flushes was recorded in a diary. Endometrial thickness was measured by means of transvaginal ultrasound; the uterine, internal carotid, and middle cerebral arteries were evaluated using Doppler ultrasound.

MAIN OUTCOME MEASURE(S)

The daily number of hot flushes, endometrial thickness, and arterial pulsatility index (PI).

RESULT(S)

Both treatments led to a 40% reduction in the number of hot flushes. Soy-derived isoflavones had no effect on endometrial thickness or the PI of the uterine and cerebral arteries.

CONCLUSION(S)

The daily administration of 72 mg of soy-derived isoflavones is no more effective than placebo in reducing hot flushes in postmenopausal women. It also has no effect on endometrial thickness or the PI of the uterine and cerebral arteries.

Endogenous estradiol and risk of dementia in women and men: the Rotterdam Study

We determined whether higher endogenous estradiol levels were associated with lower risk of dementia in older men and women not using hormonal replacement therapy, using a case-cohort design within the Rotterdam Study, a population-based follow-up study on chronic diseases, including dementia, in 7983 subjects aged 55 years or older, and ongoing since 1990. The analyses were based on a random subcohort of 508 women and 438 men, and on 76 women and 53 men with incident dementia. Cox proportional hazards models with robustly estimated standard errors showed that in women higher levels of total estradiol were associated with higher risk of dementia (age-adjusted hazard ratio per standard deviation increase 1.38; 95% CI 1.04-1.84). Age-adjusted HR's of Alzheimer's disease and vascular dementia associated with higher levels of total estradiol (per SD increase) were 1.24 (95% CI 0.87-1.76) and 2.19 (95% CI 1.22-3.92), respectively. Similar results were observed for bioavailable estradiol. Additional adjustments for potential confounders did not change the results substantially. In men, no clear association was observed between estradiol levels and risk of dementia or its subtypes. The findings do not support the hypothesis that higher levels of endogenous estradiol reduce risk of dementia, neither in women nor in men.