Effect of postmenopausal hormone therapy on cognitive function: the Heart and Estrogen/progestin Replacement Study

Surgical versus natural menopause: cognitive issues

OBJECTIVE

Women who undergo both natural and surgical menopause experience the loss of cyclic ovarian production of estrogen, but hormonal and demographic differences distinguish these two groups of women. Our objective was to review published evidence on whether the premature cessation of endogenous estrogen production in women who underwent a surgical menopause has deleterious consequences for cognitive aging and to determine whether consequences differ for women if they undergo natural menopause. Studies of estrogen-containing hormone therapy are relevant to this issue.

DESIGN

We reviewed evidence-based research, including the systematic identification of randomized clinical trials of hormone therapy with cognitive outcomes that included an objective measure of episodic memory.

RESULTS

As inferred from very small, short-term, randomized, controlled trials of high-dose estrogen treatment, surgical menopause may be accompanied by cognitive impairment that primarily affects verbal episodic memory. Observational evidence suggests that the natural menopausal transition is not accompanied by substantial changes in cognitive abilities. For initiation of hormone therapy during perimenopause or early postmenopause when the ovaries are intact, limited clinical trial data provide no consistent evidence of short-term benefit or harm. There is stronger clinical trial evidence that initiation of hormone therapy in late postmenopause does not benefit episodic memory or other cognitive skills.

CONCLUSIONS

Further research is needed on the long-term cognitive consequences of surgical menopause and long-term cognitive consequences of hormone therapy initiated near the time of surgical or natural menopause. A potential short-term cognitive benefit might be weighed when a premenopausal woman considers initiation of estrogen therapy at the time of, or soon after, hysterectomy and oophorectomy for benign conditions, although data are still quite limited and estrogen is not approved for this indication. Older postmenopausal women should not initiate hormone therapy to improve or maintain cognitive skills.

Hot flashes and estrogen therapy do not influence cognition in early menopausal women

OBJECTIVE

To examine how menopausal symptoms and estrogen therapy (ET)-induced symptom relief affect cognition in early menopause.

DESIGN

There were two components. Part 1 was a cross-sectional study of 37 healthy, recently postmenopausal women with diverse menopausal symptoms. Women were categorized as having low (n=20) or high symptoms (n=17) based on a validated symptom questionnaire. Women completed mood and sleep questionnaires and underwent cognitive testing, which included verbal memory, visual memory, emotional memory, and verbal fluency. Thirty-two of these women went on to part 2 of the study. Fourteen were randomly assigned to receive ET and 18 to receive placebo for 8 weeks. Before treatment and at 4 and 8 weeks, women completed the same measures as in part 1 of the study.

RESULTS

High symptom women had more negative mood (P=0.01) and lower quality sleep (P<0.001) than low symptom women. Despite suffering from more menopausal symptoms, worse mood, and poorer sleep, women in the high symptom group performed the same on cognitive testing as women in the low symptom group. Women receiving ET had greater improvements in menopausal symptoms and sleep compared with those receiving the placebo (P<or=0.05). ET did not improve mood compared with placebo. Women receiving ET did not have any improvement in cognitive performance compared with those receiving the placebo.

CONCLUSIONS

Menopausal symptoms do not impair cognition. ET does not improve cognition despite alleviating symptoms and improving sleep in recently naturally menopausal women with diverse menopausal symptoms.

Endogenous estrogen is not associated with cognitive performance before, during, or after menopause

OBJECTIVE

In a population-based sample of women (45, 50, or 55 years old), behavioral data and blood serum were collected concurrently, enabling us (1) to investigate cognitive differences among premenopausal, perimenopausal, and postmenopausal groups of women and (2) to evaluate the relationship between blood estrogen levels and cognitive performance.

DESIGN

Groups of premenopausal (n = 129), perimenopausal (n = 58), and postmenopausal (n = 55) women were tested on tasks assessing episodic and semantic memory, verbal fluency, visuospatial performance, and face recognition. Blood serum was collected concurrently for analyses of estrogen levels.

RESULTS

With inclusion of controls for age and education, results showed that there were no differences in cognitive performance among premenopausal, perimenopausal, and postmenopausal groups of women. In addition, there were no associations between blood estrogen levels and cognitive performance.

CONCLUSIONS

These results do not support the hypothesis that estrogen or menopausal status affects cognitive performance in middle-aged women.

The stress system in depression and neurodegeneration: focus on the human hypothalamus

The stress response is mediated by the hypothalamo-pituitary-adrenal (HPA) system. Activity of the corticotropin-releasing hormone (CRH) neurons in the hypothalamic paraventricular nucleus (PVN) forms the basis of the activity of the HPA-axis. The CRH neurons induce adrenocorticotropin (ACTH) release from the pituitary, which subsequently causes cortisol release from the adrenal cortex. The CRH neurons co-express vasopressin (AVP) which potentiates the CRH effects. CRH neurons project not only to the median eminence but also into brain areas where they, e.g., regulate the adrenal innervation of the autonomic system and affect mood. The hypothalamo-neurohypophysial system is also involved in stress response. It releases AVP from the PVN and the supraoptic nucleus (SON) and oxytocin (OXT) from the PVN via the neurohypophysis into the bloodstream. The suprachiasmatic nucleus (SCN), the hypothalamic clock, is responsible for the rhythmic changes of the stress system. Both centrally released CRH and increased levels of cortisol contribute to the signs and symptoms of depression. Symptoms of depression can be induced in experimental animals by intracerebroventricular injection of CRH. Depression is also a frequent side effect of glucocorticoid treatment and of the symptoms of Cushing's syndrome. The AVP neurons in the hypothalamic PVN and SON are also activated in depression, which contributes to the increased release of ACTH from the pituitary. Increased levels of circulating AVP are also associated with the risk for suicide. The prevalence, incidence and morbidity risk for depression are higher in females than in males and fluctuations in sex hormone levels are considered to be involved in the etiology. About 40% of the activated CRH neurons in mood disorders co-express nuclear estrogen receptor (ER)-alpha in the PVN, while estrogen-responsive elements have been found in the CRH gene promoter region, and estrogens stimulate CRH production. An androgen-responsive element in the CRH gene promoter region initiates a suppressing effect on CRH expression. The decreased activity of the SCN is the basis for the disturbances of circadian and circannual fluctuations in mood, sleep and hormonal rhythms found in depression. Neuronal loss was also reported in the hippocampus of stressed or corticosteroid-treated rodents and primates. Because of the inhibitory control of the hippocampus on the HPA-axis, damage to this structure was expected to disinhibit the HPA-axis, and to cause a positive feedforward cascade of increasing glucocorticoid levels over time. This 'glucocorticoid cascade hypothesis' of stress and hippocampal damage was proposed to be causally involved in age-related accumulation of hippocampal damage in disorders like Alzheimer's disease and depression. However, in postmortem studies we could not find the presumed hippocampal damage of steroid overexposure in either depressed patients or in patients treated with synthetic steroids.

The Effect of 3-Year Treatment with 0.25 mg/day of Micronized 17β-Estradiol on Cognitive Function in Older Postmenopausal Women

OBJECTIVES

To evaluate the effect of ultra-low-dose (0.25 mg/d) micronized 17beta-estradiol on cognitive function in older postmenopausal women.

DESIGN

Randomized, placebo-controlled trial conducted for 3 years.

SETTING

Academic health center in greater Hartford, Connecticut.

PARTICIPANTS

Fifty-seven healthy, community-dwelling, older postmenopausal women.

INTERVENTION

Women received 0.25 mg/d of micronized 17beta-estradiol (estrogen therapy (ET), n=32) or placebo (n=25); all women who had not had a hysterectomy received 100 mg/d of oral micronized progesterone for 2-week periods every 6 months.

MEASUREMENTS

Neuropsychological measures of memory, language, mood, and executive function were collected at baseline, 3 months, and 36 months. Measures of executive function included the Controlled Oral Word Association Test, the Trail Making Test, and the Wisconsin Card Sorting Test. The Boston Naming Test was used to measure language skills. The Symbol Digit Modalities Test was used as a measure of sustained attention. Measures of memory included the Complex Figure Test, Fuld Object Memory Test, and a selected subtest from the Wechsler Memory Scale. Scores from the Geriatric Depression Scale and the Beck Anxiety Inventory were used to assess symptoms of depression.

RESULTS

No differences were found between ET and placebo on any of the neurocognitive measures or depression instruments, nor were there any differences when the groups were stratified according to age.

CONCLUSION

This small study, which had adequate power to detect change in some but not all domains of cognition tested, revealed that low-dose estrogen neither benefits nor harms cognitive function in older women after 3 years of treatment, but confirmation is needed from larger trials.

Endogenous sex hormone levels and risk of cognitive decline in an older biracial cohort

BACKGROUND

Older women treated with conjugated estrogens may have an increased risk of dementia, but the effect of naturally occurring sex hormones on cognition is not certain.

METHODS

Bioavailable estradiol and free testosterone level were obtained from 792 (55% men, 51% black) participants. We assessed cognition with the Modified Mini-Mental State Examination (3MS), Selective Reminding Test (SRT) and CLOX 1 at baseline and 2 years later.

RESULTS

Women in the lowest estradiol tertile were more likely than those in the highest tertile to decline (> or = 1.0 S.D. of change) on 3MS (25% versus 9%, adjusted odds ratio [OR] = 3.9; 95% confidence interval [CI] = 1.6-9.6) and on SRT (28% versus 12%, adjusted OR [95% CI] = 3.3 [1.4-7.9]) but not CLOX 1. There was a borderline association between low estradiol tertile and decline on SRT in men (22% versus 14%, adjusted OR [95% CI] = 1.9 [0.9-3.9]). Testosterone level was not associated with decline in cognition in either men or women. Findings did not differ by race.

CONCLUSIONS

Older women with low estradiol levels were more likely to experience decline in global cognitive function and verbal memory, and a similar trend was observed for verbal memory in men. This supports the hypothesis that endogenous sex hormones may play an important role in the maintenance of cognitive function in older adults.

Complex actions of sex steroids in adipose tissue, the cardiovascular system, and brain: Insights from basic science and clinical studies

Recent publications describing the results of the Women's Health Initiative (WHI) and other studies reporting the impact of hormone therapy on aging women have spurred reexamination of the broad use of estrogens and progestins during the postmenopausal years. Here, we review the complex pharmacology of these hormones, the diverse and sometimes opposite effects that result from the use of different estrogenic and progestinic compounds, given via different delivery routes in different concentrations and treatment sequence, and to women of different ages and health status. We examine our new and growing appreciation of the role of estrogens in the immune system and the inflammatory response, and we pose the concept that estrogen's interface with this system may be at the core of some of the effects on multiple physiological systems, such as the adipose/metabolic system, the cardiovascular system, and the central nervous system. We compare and contrast clinical and basic science studies as we focus on the actions of estrogens in these systems because the untoward effects of hormone therapy reported in the WHI were not expected. The broad interpretation and publicity of the results of the WHI have resulted in a general condemnation of all hormone replacement in postmenopausal women. In fact, careful review of the extensive literature suggests that data resulting from the WHI and other recent studies should be interpreted within the narrow context of the study design. We argue that these results should encourage us to perform new studies that take advantage of a dialogue between basic scientists and clinician scientists to ensure appropriate design, incorporation of current knowledge, and proper interpretation of results. Only then will we have a better understanding of what hormonal compounds should be used in which populations of women and at what stages of menopausal/postmenopausal life.

The Women's Health Initiative Study of Cognitive Aging (WHISCA): a randomized clinical trial of the effects of hormone therapy on age-associated cognitive decline

The Women's Health Initiative Study of Cognitive Aging (WHISCA) was a two armed, randomized, placebo controlled, clinical trial designed to assess the efficacy of postmenopausal hormone therapy on age related changes in specific cognitive functions. WHISCA was an ancillary study to the Women's Health Initiative (WHI) and the WHI Memory Study (WHIMS) and enrolled 2302 women aged 66 to 84 years (mean 73.9; standard deviation 3.8) who did not meet criteria for dementia. Women were randomly assigned by the WHI to hormone treatment (unopposed conjugated estrogens (CEE) 0.625 mg/day if they were without a uterus; CEE combined with medroxyprogesterone acetate (MPA) 2.5 mg/day otherwise) or placebo for an average of three years before the first WHISCA assessment. WHISCA investigated the effects of hormone therapy on rates of change over time in memory, other aspects of cognition (language, attention, spatial ability), motor function, and mood. In this paper, we present the study rationale and design, including specific cognitive measures, and the challenges of incorporating WHISCA into an ongoing randomized trial. WHISCA provided a unique opportunity to investigate the potential of hormone therapy to modify age related changes in specific cognitive functions. WHISCA also demonstrated the feasibility of adding a detailed cognitive assessment into an ongoing clinical trial to address an important issue in women's health, despite the challenges of maintaining the integrity of the parent studies, ensuring high retention, and achieving high quality assurance across sites.

Verified hormone therapy improves episodic memory performance in healthy postmenopausal women

Studies of hormone therapy (HT) and cognition have yielded conflicting results. The aim of this observational study was to examine the effect of estradiol, via serum verified HT (estradiol, estriol, progesterone) and endogenous estradiol, on 108 healthy postmenopausal women's cognitive performance. The results demonstrated that the 43 HT-users performed at a significantly higher level than non-users on episodic memory tasks and on a verbal fluency task, whereas HT-users and non-users did not differ on tasks assessing semantic memory and spatial visualization. In addition, there was a positive relationship between serum estradiol level and episodic memory performance, indicating that postmenopausal HT is associated with enhanced episodic memory and verbal fluency, independent of age and education. These observational results suggest that HT use may be sufficient to exert small, yet positive effects on female sensitive cognitive tasks. Hormone therapy compliance and formulation is discussed as confounding factors in previous research.

Estrogen treatment effects on anticholinergic-induced cognitive dysfunction in normal postmenopausal women

Estrogen has been shown to interact with the cholinergic system and influence cognition in animal models. This study investigated the interaction of estrogen and cholinergic system functioning and the effects of this interaction on cognitive task performance in healthy older women. Fifteen post-menopausal women were randomly and blindly placed on 1 mg of 17-beta estradiol or placebo for 3 months after which they participated in five anticholinergic challenge sessions, where they were administered one of two doses of the antimuscarinic drug scopolamine (SCOP) or the antinicotinic drug mecamylamine (MECA) or placebo. After the first challenge phase, they were crossed over to the other hormone treatment for another 3 months and repeated the challenges. Performance in multiple domains of cognition was assessed during anticholinergic drug challenge, including attention and verbal and nonverbal learning and memory. Results showed that estrogen pretreatment attenuated the anticholinergic drug-induced impairments on tests of attention and tasks with speed components. This study is the first to demonstrate the interaction of estrogen and the cholinergic system and the effects on cognitive performance in humans. The results suggest that estrogen status may affect cholinergic system tone and may be important for cholinergic system integrity.

The neurology of menopause

BACKGROUND

Menopause is a normal milestone experienced annually by 2 million American women each year, and many women are concerned about the relation between menopause and health. Associated hormonal changes have the potential to influence neurologic disease, as do hormonal therapies prescribed for menopausal symptoms or other conditions. The objective of this article is to increase neurologists' awareness of the relation between menopause and neurologic illness.

REVIEW SUMMARY

This was a focused review of 4 common neurologic disorders potentially influenced by menopause or by estrogen-containing hormone therapy: stroke, epilepsy, Parkinson disease, and Alzheimer disease. Hormonal effects are germane to each illness, although clinical implications are clearer for stroke and Alzheimer disease than for epilepsy and Parkinson disease. For women with epilepsy, few clinical data directly address the role of menopause or estrogen-containing hormone therapy on seizure frequency. Relevant clinical research findings on Parkinson disease are inconsistent and provide an inadequate basis for practice guidelines. There is clinical trial evidence that hormone therapy does not reduce stroke incidence and may increase risk of ischemic stroke; hormone therapy cannot be recommended for stroke prevention. The natural menopausal transition is not characterized by objective memory loss. There is clinical trial evidence that hormone therapy should not be used for the postmenopausal woman age 65 years or older for the preservation of cognitive skills, prevention of dementia, or treatment of dementia due to Alzheimer disease. Long-term cognitive consequences of short-term hormone therapy used by younger women for menopausal symptoms remains an important area of uncertainty.

CONCLUSIONS

Increased awareness of hormonal influences on neurologic illness is important for the practicing neurologist.

Estrogen therapy selectively enhances prefrontal cognitive processes: a randomized, double-blind, placebo-controlled study with functional magnetic resonance imaging in perimenopausal and recently postmenopausal women

OBJECTIVE

Estrogen therapy (ET) seems to differentially effect cognitive processes in younger versus older postmenopausal women, suggesting a window of opportunity when ET is most beneficial. Cognitive improvement in younger postmenopausal women has been attributed to ET's influence on hot flushes and sleep, but empiric examination of the mediating role of menopause symptoms versus direct effects of ET on the brain is limited.

DESIGN

In a double-blind trial, 52 women were randomly assigned to estradiol 0.05 mg/day (n = 26) or placebo transdermal patches (n = 26) for 12 weeks. Women completed tests of memory, learning, and executive functioning, and hot flush and sleep assessments at baseline and study end. A subset of women (five ET treated, six placebo treated) also underwent blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) studies.

RESULTS

Nondepressed perimenopausal and postmenopausal women were studied. The majority had hot flushes and sleep impairment. Compared with placebo, ET selectively reduced errors of perseveration during verbal recall (P = 0.03), a frontal system-mediated function, but did not influence other cognitive processes. Women with baseline hot flushes had greater cognitive benefit with ET (P < 0.05). Cognitive benefit was not associated with sleep problems or its improvement. Measures of fMRI BOLD activation during tests of verbal and spatial working memory showed significant increases in frontal system activity with ET (P < 0.001).

CONCLUSIONS

Estrogen therapy selectively improves executive functioning as demonstrated by reduced perseverative errors and prefrontal cortex activation during verbal recall tasks. Cognitive improvement with ET is associated with hot flushes, but not with sleep, suggesting that ET has a direct central nervous system effect, rather than an indirect effect mediated through improvement of sleep.

The selective estrogen receptor-beta agonist biochanin A shows vasculoprotective effects without uterotrophic activity

OBJECTIVE

Current hormone therapy in postmenopausal women is associated with uterotrophic activity and cancer-promoting effects. In this experimental study, we compared the effects of the selective estrogen-receptor (ER) beta agonist biochanin A, and the selective ERalpha agonist ethinylestradiol, on the development of intimal hyperplasia after balloon injury and on uterus morphology.

DESIGN

Female F344 rats with or without prior ovariectomy were used for aortic denudations. Animals remained untreated or received oral biochanin A (100 mg/kg) or ethinylestradiol (100 microg/kg). After 14 days, aortas and uteri were harvested for histologic and immunohistochemical analyses. Computerized assessments of aortic adhesion molecule expression, and isometric relaxation experiments, and uteri were analyzed. In vitro studies with smooth muscle cells and endothelial cells were performed to further investigate the effects of hormone treatment on cell proliferation, migration and adhesion molecule expression.

RESULTS

Among untreated rats, ovariectomized animals tended to show greater neointimal hyperplasia and increased expression of the adhesion molecules 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1). Biochanin A treatment reduced neointima formation, inhibited VCAM-1 up-regulation, and improved the vascular relaxation response. No effect was observed on uterus growth or histology. Ethinylestradiol also reduced aortic neointima formation and inhibited VCAM-1 up-regulation, but failed to improve endothelial function and significantly induced uterus growth. Both agents showed antiproliferative and weak antimigratory effects on smooth muscle cells, and reduced VCAM-1 expression on stimulated endothelial cells in vitro.

CONCLUSIONS

The ERbeta agonist biochanin A shows vasculoprotective effects without uterotrophic activity. Because hormone therapy may have cancer-promoting side effects, administration of ERbeta-selective agents might be alternatively used to reduce the risk of cardiovascular disease in postmenopausal women.

The effect of hormone replacement therapy on the levels of serum lipids, apolipoprotein AI, apolipoprotein B and lipoprotein (a) in Turkish postmenopausal women

OBJECTIVES

Estrogen replacement therapy alters the lipid profiles favorably for delaying atherosclerosis in postmenopausal women. The effects of estrogen plus progesterone combination therapy on lipids are controversial. This study was designed to evaluate the effect of female sex hormones on lipids and lipoproteins and to clarify the influence of progesterone on the effect of estrogen in postmenopausal women.

METHODS

Of the 60 postmenopausal women admitted to our menopause clinic, 40 had intact uterus and received continuous 0.625 mg conjugated equine estrogen (CEE) plus 2.5 mg medroxyprogesterone acetate (MPA), whereas the remaining 20 were hysterectomized and received 0.625 mg CEE daily. To assess the alterations in lipids and lipoproteins during menopause, 45 healthy premenopausal women were investigated. Lipid and lipoprotein levels were assessed in each subject at baseline and at the 6th and 18th months of therapy.

RESULTS

In menopause, a shift towards more atherogenic lipid and lipoprotein profiles than those of the premenopausal state was found. Following 18 months of treatment, both regimens reduced total cholesterol (TC) levels as compared with the baseline (6.4 vs. 6.9% in the CEE/MPA and CEE groups, respectively). The CEE group had a more pronounced increase in high-density lipoprotein (HDL) cholesterol than the CEE/MPA group (10.3 vs. 8.8%, respectively). Both groups displayed reduced TC, low-density lipoprotein (LDL) cholesterol and apolipoprotein-B (ApoB) concentrations, whereas triglycerides increased, with a greater tendency to increase in the CEE/MPA group at the end of the trial. Also, the lipoprotein (a) [Lp(a)] levels decreased significantly (27.6 vs. 24.5% in the CEE/MPA and CEE groups, respectively). This decrease was more pronounced in subjects with a relatively higher basal Lp(a) concentration.

CONCLUSION

Both treatment regimens caused positive alterations in the lipid and lipoprotein profiles. This association might play a pivotal role in the postmenopausal increases in atherosclerotic diseases and cardioprotective effect of estrogen in postmenopausal women.

A systematic review of clinical trials of hormone therapy on cognitive function: effects of age at initiation and progestin use

The putative protective effects of hormone therapy (HT) have been cast in doubt by recent findings from the Women's Health Initiative Memory Study showing an increase in dementia and an increased likelihood of impaired cognitive status in women initiating HT after age 65. To explore the external generalizability of those findings to younger postmenopausal women, the medical literature was surveyed for randomized, double-blind, placebo-controlled trials of treatment with either estrogen alone or estrogen plus a progestin on neuropsychological test performance. Findings from trials in younger women (<65 years) are presented separately from those in older women (>or=65 years). This review finds little support for beneficial cognitive effects in older women of estrogen alone or in combination with progestin. However, evidence from younger women suggests potential beneficial effects in select cognitive domains, particularly among symptomatic women and recently menopausal women, and scant evidence of harm. There is a dearth of studies of the cognitive effects of estrogen plus progestin in younger women. Future studies systematically exploring the effect of age and progestin use are needed to better characterize the effects of HT on cognition in younger women. Without firm evidence of benefit to younger women, it is prudent to caution early postmenopausal women about the cognitive risks observed in WHI, recognizing the low likelihood of dementia at that age.

Gender disparities in Parkinson's disease

Parkinson's disease is a chronic neurodegenerative disorder of unknown etiology. There are sparse data on gender differences in this disorder, but it is clear that there are gender discrepancies in incidence, symptoms, medication effects and treatments. There also appear to be lifecycle fluctuations in the disease course of female Parkinson's disease patients. The effect of estrogen in this disorder is multifold and its role in the development and treatment of PD will be discussed.

Global Protein Expression Profiling Underlines Reciprocal Regulation of Caveolin 1 and Endothelial Nitric Oxide Synthase Expression in Ovariectomized Sheep Uterine Artery by Estrogen/Progesterone Replacement Therapy1

Ovariectomized (OVX) ewes were assigned to receive vehicle, progesterone (P4, 0.9-g controlled internal drug release vaginal implants), estradiol-17beta (E2, 5 microg/kg bolus + 6 microg kg(-1) day(-1)), or P4 + E2 for 10 days (n = 3/group). Uterine artery endothelial proteins were mechanically isolated on Day 10. The samples were used for protein expression profiling by the Ciphergen Proteinchip system and immunoblotting analysis of endothelial nitric oxide synthase (NOS3, also termed eNOS) and caveolin 1. Uterine artery rings were cut and analyzed by immunohistochemistry to localize NOS3 and caveolin 1 expression. With the use of the IMAC3 protein chip with loading as little as 2 microg protein/sample, many protein peaks could be detected. Compared to vehicle controls, a approximately 133.1-kDa protein was identified to be upregulated by 2- to 4-fold in OVX ewes receiving E2, P4, and their combination, whereas a approximately 22.6-kDa protein was downregulated by 2- to 4-fold in OVX ewes receiving E2 and E2/P4, but not P4 treatments. Western blot analysis revealed that E2, P4, and their combination all increased NOS3 protein, whereas E2 and its combination with P4, but not P4 alone, downregulated caveolin 1 expression. Immunohistochemical analysis revealed that NOS3 was mainly localized in the endothelium and upregulated by E2, whereas caveolin 1 was localized in both endothelium and smooth muscle and downregulated by E2. Thus, our data demonstrate that uterine artery endothelial NOS3 and caveolin 1 are regulated reciprocally by estrogen replacement therapy. In keeping with the facts that E2, but not P4, causes uterine vasodilatation and that E2 and P4 increase NOS3 expression, but only E2 decrease caveolin 1 expression, our current study suggests that both increased NOS3 expression and decreased caveolin 1 expression are needed to facilitate estrogen-induced uterine vasodilatation.

Postmenopausal hormone therapy: new questions and the case for new clinical trials

Observational studies suggest that postmenopausal hormone therapy (HT) prevents coronary heart disease, whereas randomized clinical trials have not confirmed a cardioprotective effect. Although observational studies may have overestimated the coronary benefit conferred by postmenopausal hormone use, there are other plausible explanations for the apparent discrepancy between previous results and the less favorable findings from clinical trials such as the large Women's Health Initiative. There is now a critical mass of data to support the hypothesis that age or time since menopause may importantly influence the benefit-risk ratio associated with HT, especially with respect to cardiovascular outcomes, and that the method of administration, dose, and formulation of exogenous hormones may also be relevant. Although the weight of the evidence indicates that older women and those with subclinical or overt coronary heart disease should not take HT, estrogen remains the most effective treatment currently available for vasomotor symptoms, and its effects on the development of coronary disease in newly postmenopausal women remain unclear. Moreover, effects of HT on quality of life and cognitive function in recently postmenopausal women merit further study. These unresolved clinical issues provide the rationale for the design of the Kronos Early Estrogen Prevention Study, a 5-year randomized trial that will evaluate the effectiveness of low-dose oral estrogen and transdermal estradiol in preventing progression of atherosclerosis in recently postmenopausal women.

Effects of estrogen and progesterone on spatial memory consolidation in aged females

Interpretation of data illustrating that estrogen, with or without progestin, is detrimental to memory in post-menopausal women is complicated by the fact that little is known about the effects of progestins on memory. The present study examined if estrogen, alone or with progesterone, affects spatial memory consolidation in ovariectomized aged female mice. Mice received eight training trials in a spatial Morris water maze followed immediately by injection of water-soluble 17beta-estradiol (E(2); 0.2 mg/kg) or vehicle. Mice were re-tested 24 h later. All mice learned to find the platform on Day 1. On Day 2, the performance of control, but not E(2) mice, deteriorated, suggesting that E(2) enhanced memory for the platform location. In a second experiment, mice were injected with E(2) and 10 or 20 mg/kg water-soluble progesterone. The 10 mg/kg dose of progesterone did not affect estrogen's ability to enhance spatial memory consolidation, but 20 mg/kg blocked this effect. These data indicate that estrogen can improve spatial memory consolidation in aged females and that this effect can be attenuated by progesterone.

Select estrogens within the complex formulation of conjugated equine estrogens (Premarin) are protective against neurodegenerative insults: implications for a composition of estrogen therapy to promote neuronal function and prevent Alzheimer's disease

BACKGROUND

Results of the Women's Health Initiative Memory Study (WHIMS) raised concerns regarding the timing and formulation of hormone interventions. Conjugated equine estrogens (CEE), used as the estrogen therapy in the WHIMS trial, is a complex formulation containing multiple estrogens, including several not secreted by human ovaries, as well as other biologically active steroids. Although the full spectrum of estrogenic components present in CEE has not yet been resolved, 10 estrogens have been identified. In the present study, we sought to determine which estrogenic components, at concentrations commensurate with their plasma levels achieved following a single oral dose of 0.625 mg CEE (the dose used in the WHIMS trial) in women, are neuroprotective and whether combinations of those neuroprotective estrogens provide added benefit. Further, we sought, through computer-aided modeling analyses, to investigate the potential correlation of the molecular mechanisms that conferred estrogen neuroprotection with estrogen interactions with the estrogen receptor (ER).

RESULTS

Cultured basal forebrain neurons were exposed to either beta-amyloid(25-35) or excitotoxic glutamate with or without pretreatment with estrogens followed by neuroprotection analyses. Three indicators of neuroprotection that rely on different aspects of neuronal damage and viability, LDH release, intracellular ATP level and MTT formazan formation, were used to assess neuroprotective efficacy. Results of these analyses indicate that the estrogens, 17alpha-estradiol, 17beta-estradiol, equilin, 17alpha-dihydroequilin, equilinen, 17alpha-dihydroequilenin, 17beta-dihydroequilenin, and Delta8,9-dehydroestrone were each significantly neuroprotective in reducing neuronal plasma membrane damage induced by glutamate excitotoxicity. Of these estrogens, 17beta-estradiol and Delta8,9-dehydroestrone were effective in protecting neurons against beta-amyloid25-35-induced intracellular ATP decline. Coadministration of two out of three neuroprotective estrogens, 17beta-estradiol, equilin and Delta8,9-dehydroestrone, exerted greater neuroprotective efficacy than individual estrogens. Computer-aided analyses to determine structure/function relationships between the estrogenic structures and their neuroprotective activity revealed that the predicted intermolecular interactions of estrogen analogues with ER correlate to their overall neuroprotective efficacy.

CONCLUSION

The present study provides the first documentation of the neuroprotective profile of individual estrogens contained within the complex formulation of CEE at concentrations commensurate with their plasma levels achieved after an oral administration of 0.625 mg CEE in women. Our analyses demonstrate that select estrogens within the complex formulation of CEE contribute to its neuroprotective efficacy. Moreover, our data predict that the magnitude of neuroprotection induced by individual estrogens at relatively low concentrations may be clinically undetectable and ineffective, whereas, a combination of select neuroprotective estrogens could provide an increased and clinically meaningful efficacy. More importantly, these data suggest a strategy for determining neurological efficacy and rational design and development of a composition of estrogen therapy to alleviate climacteric symptoms, promote neurological health, and prevent age-related neurodegeneration, such as AD, in postmenopausal women.

Estrogen-containing hormone therapy and Alzheimer’s disease risk: Understanding discrepant inferences from observational and experimental research

Estrogen has the potential to influence brain processes implicated in Alzheimer's disease pathogenesis. With the loss of ovarian estrogen production after menopause, estrogen-containing hormone therapy might be expected to influence the risk of Alzheimer's disease. Observational data link use of hormone therapy to reductions in Alzheimer risk, but experimental evidence from the Women's Health Initiative Memory Study trial demonstrates that oral estrogen, with or without a progestin, increases the incidence of dementia for postmenopausal women age 65 years or older. Mechanisms of harm in this setting are unknown. Bias and unrecognized confounding in observational research are leading candidates for discrepant results between observational studies and the Women's Health Initiative Memory Study trial. Studies are also distinguished by differences in outcome measures, hormone therapy formulations, prevalence of menopausal symptoms among study participants, and participant age. Finally, Women's Health Initiative Memory Study findings may not generalize to estrogen use by relatively young women during the menopausal transition or early postmenopause, a class of women who were ineligible for the Women's Health Initiative Memory Study trial. In observational studies, hormone therapy exposure often included use by younger women for menopausal vasomotor symptoms. Although there is no clinical trial evidence that hormone therapy at any age protects against Alzheimer's disease, it remains to be determined whether the age at which hormone exposure occurs or the timing of hormone therapy initiation in relation to the menopause (the critical window hypothesis) modifies treatment outcomes on dementia risk.

Hormone therapy and cognitive function: is there a critical period for benefit?

The large majority of women receiving hormone therapy initiate therapy early in life for the treatment of menopausal symptoms. However, the Women's Health Initiative Memory Study, the only randomized clinical trial to date on hormone therapy and dementia, was carried out in women age 65 and older. That trial provided important insights into the detrimental effects of hormone therapy on dementia in women initiating later in life. The generalizability of those findings to the typical hormone therapy user who initiates earlier in life is unknown. To address this important issue, this review focuses on observational trials of hormone therapy and dementia risk, randomized clinical trials of hormone therapy and cognitive function, and basic science studies. These lines of research provide suggestive, but not definitive, evidence that early initiation of hormone therapy may provide cognitive benefits, particularly to verbal memory and other hippocampally mediated functions. Other forms of hormone therapy, other cognitive domains, and cyclic hormone regimens may not conform to this "critical period hypothesis." Further research is needed to test the validity and limits of this hypothesis.

Current Status of Combined Hormone Replacement Therapy in Clinical Practice

Approximately 20 million women worldwide use hormone replacement therapy (HRT). Formerly, it was thought to confer beneficial cardiac protection and reduce osteoporosis in addition to relieving the symptoms of menopause. However, many recent trials have contradicted these beliefs. The risk of breast cancer associated with HRT use has been well documented but underestimated. Many recent trials have reported higher than expected breast cancer incidence rates, particularly associated with combined HRT. Although it was believed estrogen conferred cardiac protection and reduced the incidence of myocardial ischemic events and cerebrovascular accidents, the more recent literature indicates that this is not true and that HRT users have a higher risk of cardiac and cerebral events. The role of HRT in clinical practice has been redefined. It is no longer an acceptable form of treatment for most women. The evidence indicates that the use of long-term HRT is no longer clinically justifiable.

Cognitive function across the life course and the menopausal transition in a British birth cohort

OBJECTIVE

Despite biological plausibility, relationships between menopause and cognitive function are inconsistent. We investigated whether menopause status and menopause age were associated with general cognitive ability, verbal memory, and visual search speed and concentration in a large cohort of women while considering vasomotor and psychological symptoms, previous childhood and adult measures of cognitive function, lifetime socioeconomic circumstances, educational attainment, lifestyle factors, and chronic diseases.

DESIGN

A nationally representative British cohort of 1261 women born in March 1946 and all aged 53 years at cognitive testing, with prospective information on previous cognitive function, menopausal characteristics, and potential confounders.

RESULTS

There was only weak evidence of the effect of natural menopause on cognitive function and no evidence of any effects of hormone therapy use or hysterectomy status. There was a trend across the phases of the natural menopausal transition (pre-, peri-, and postmenopause) for the National Adult Reading Test (P = 0.005) and search speed and concentration (P = 0.042), with postmenopausal women having the lowest cognitive function, but there was no trend in verbal memory. Variation in vasomotor and psychological symptoms did not explain these trends. In postmenopausal women, there was a positive trend across menopause age for verbal memory (P = 0.004) and a weak positive trend for the National Adult Reading Test (P = 0.052), with women who reached menopause later having higher cognitive function. Previous cognitive function generally explained the associations, which were further weakened by adjusting for socioeconomic and educational confounders. One exception was the association between the natural menopause transition and search speed and concentration, which remained after adjustment for these factors.

CONCLUSION

Menopause adversely affects cognitive function, but this effect may be largely explained by premenopausal cognitive function. These findings suggest that common environmental or genetic factors, operating through long-term or lifelong hormonal mechanisms, may influence the timing of natural menopause and lifetime cognitive function.

Hormone replacement therapy and cognitive performance in postmenopausal women—a review by cognitive domain

Laboratory, animal and neuroimaging evidences suggest that hormone replacement therapy (HRT) may be beneficial to human cognition. This systematic review includes 26 studies on the association between HRT and cognition and 17 studies on HRT and risk of dementia. It was hypothesised that HRT would have a positive association with cognitive speed and verbal memory and possibly visual memory but not with executive functioning, and would be associated with a decreased risk of dementia. Evidence for HRT's neuroenhancing and neuroprotective properties was also evaluated. There was significant statistical and clinical heterogeneity among studies precluding meta-analysis. Results showed no consistent relationship between HRT and performance in any cognitive domain. Cross-sectional studies tended to report more positive results than longitudinal studies and randomised-controlled trials, particularly in the areas of verbal memory and executive functioning. HRT was associated with decreased risk of dementia in observational studies, but with increased risk in one randomised-controlled trial. Cognitive improvement or maintenance are not secondary benefits of HRT.

Long term hormone therapy for perimenopausal and postmenopausal women

BACKGROUND

Hormone therapy (HT) is widely used for controlling menopausal symptoms. It has also been used for the management and prevention of cardiovascular disease, osteoporosis and dementia in older women but the evidence supporting its use for these indications is largely observational.

OBJECTIVES

To assess the effect of long-term HT on mortality, heart disease, venous thromboembolism, stroke, transient ischaemic attacks, breast cancer, colorectal cancer, ovarian cancer, endometrial cancer, gallbladder disease, cognitive function, dementia, fractures and quality of life.

SEARCH STRATEGY

We searched the following databases up to November 2004: the Cochrane Menstrual Disorders and Subfertility Group Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, Biological Abstracts. Relevant non-indexed journals and conference abstracts were also searched.

SELECTION CRITERIA

Randomised double-blind trials of HT (oestrogens with or without progestogens) versus placebo, taken for at least one year by perimenopausal or postmenopausal women.

DATA COLLECTION AND ANALYSIS

Fifteen RCTs were included. Trials were assessed for quality and two review authors extracted data independently. They calculated risk ratios for dichotomous outcomes and weighted mean differences for continuous outcomes. Clinical heterogeneity precluded meta-analysis for most outcomes.

MAIN RESULTS

All the statistically significant results were derived from the two biggest trials. In relatively healthy women, combined continuous HT significantly increased the risk of venous thromboembolism or coronary event (after one year's use), stroke (after 3 years), breast cancer (after 5 years) and gallbladder disease. Long-term oestrogen-only HT also significantly increased the risk of stroke and gallbladder disease. Overall, the only statistically significant benefits of HT were a decreased incidence of fractures and colon cancer with long-term use. Among relatively healthy women over 65 years taking continuous combined HT, there was a statistically significant increase in the incidence of dementia. Among women with cardiovascular disease, long-term use of combined continuous HT significantly increased the risk of venous thromboembolism. No trials focussed specifically on younger women. However, one trial analysed subgroups of 2839 relatively healthy 50 to 59 year-old women taking combined continuous HT and 1637 taking oestrogen-only HT, versus similar-sized placebo groups. The only significantly increased risk reported was for venous thromboembolism in women taking combined continuous HT; their absolute risk remained very low.

AUTHORS' CONCLUSIONS

HT is not indicated for the routine management of chronic disease. We need more evidence on the safety of HT for menopausal symptom control, though short-term use appears to be relatively safe for healthy younger women.

Endogenous and exogenous hormone exposure and risk of cognitive impairment in Swedish twins: a preliminary study

PURPOSE

To analyze the risk of cognitive impairment among female Swedish Twins with regard to endogenous and exogenous hormone exposure.

DESIGN AND SETTING

A cross-sectional analysis of data from the HARMONY Study, a population-based cohort study of cognitive impairment in the Swedish Twin Registry.

METHODS

Information regarding age at menarche and menopause, parity, and length and type of hormone therapy (HT) was collected via a telephone interview from 6604 women, aged 65-84. Cognitive impairment was assessed with the TELE, a brief telephone cognitive screen.

RESULTS

Length of reproductive period was inversely associated with risk of cognitive impairment (p<0.01). The OR was 1.15 (CI 95% 0.96-1.36) for women with reproductive periods <35 years and 0.82 (CI 95% 0.66-1.00) for women with reproductive periods >39 years. Age at menopause was inversely associated with risk of cognitive impairment. Use of HT was associated with average 40% decline in the risk of cognitive impairment, independent of type and timing of treatment.

CONCLUSION

Our results suggest that both increased length of reproductive period and HT are associated with reduced risk of cognitive impairment.

Endogenous oestrogens are related to cognition in healthy elderly women

OBJECTIVE

To investigate whether levels of endogenous hormones, in particular circulating oestrogens and SHBG, are associated with cognition in healthy postmenopausal women.

DESIGN

Cross-sectional study.

PATIENTS

Four hundred and two healthy postmenopausal women aged 50-74 years between 8 and 30 years after menopause, none taking oestrogen.

MEASUREMENTS

Serum concentration of oestradiol, oestrone, and sex hormone binding globulin (SHBG) determined by immunoassay. Cognition assessed using the mini-mental state examination questionnaire (MMSE).

RESULTS

In this group, 149 individuals had a MMSE score < 27, while only 89 individuals had a MMSE score < 26, indicating a relatively healthy population with regard to cognitive ability. Cognition decreased with age, time since menopause and blood pressure, and was better with higher age at menopause. Serum oestrogens and SHBG levels were not related to age, age at menopause, or time since menopause, and oestrogen levels were positively associated with blood pressure. After adjustment for mean arterial pressure and SHBG, the frequency of mild cognitive impairment decreased significantly with higher oestradiol and oestrone serum levels [ORs Q5 vs. Q1: 0.41 (95% CI 0.20-0.84) and 0.51 (95% CI 0.20-0.99) for oestradiol and oestrone, respectively].

CONCLUSIONS

Postmenopausal women with higher remaining circulating oestradiol levels appear less likely to suffer from cognitive impairment. This effect is independent of age at menopause, time since menopause and BMI. These findings support the hypothesis that endogenous oestrogens may protect against cognitive decline with ageing.

Physical activity and hormone-replacement therapy: interactive effects on cognition?

The purpose of this study was to examine the interactive effects of hormone-replacement therapy (HRT) and physical activity (PA) on the cognitive performance of older women. Postmenopausal women (n = 101) were recruited to complete a PA questionnaire, provide demographic information, and perform the digit-symbol substitution task (DSST) and the trail-making tests (TMT). Regression analyses were conducted for participants with complete data for each cognitive test (DSST n = 62; TMT n = 69). For both tasks, results indicated that PA and education were positively related and age was negatively related to cognitive performance. The interaction of HRT with PA did not add to the predicted variance of either measure of cognitive performance. This was true even after limiting the HRT users to women using unopposed estrogen. It is concluded that the beneficial relationship between PA and these two measures of cognitive performance in postmenopausal women exists irrespective of HRT use.

Clinical Pharmacology and Differential Cognitive Efficacy of Estrogen Preparations

Menopause is associated with a significant decline in levels of estrogen, which reportedly leads to several distressing symptoms and adverse health effects on various target tissues including those on bones, heart, and brain. Although effective, the long-term safety and feasibility of therapy with both unopposed and opposed oral conjugated equine estrogen has been questioned by the recent findings of both the Women's Health Initiative (WHI) and the Women's Health Initiative Memory Study (WHIMS). The findings of both these studies have raised several critical issues related to hormone therapy that need to be systematically evaluated in clinical studies. Specifically, these issues relate to the differential efficacy and adverse-effects profile of various forms of estrogen and progestins, the importance of the route of administration of estrogen, the best timing to initiate postmenopausal hormone therapy, and the efficacy of cyclic versus continuous hormone therapy. This article focuses on estrogen and discusses issues related to selecting the best form and route of administration of the hormone. It includes information on basic clinical pharmacology of various forms of estrogen, neuroendocrinology of the menopause, neurobiology of estradiol and estrone, and results of selected basic science and human intervention studies with relevance to identifying the best form and route of administration of estrogen.

The rise and fall of menopausal hormone therapy

Clinical trials show that hormone therapy (HT) is an effective treatment for vasomotor symptoms and vaginal dryness. HT improves other symptoms including sleep and quality of life in women who have menopause symptoms. In the Women's Health Initiative controlled clinical trials, both estrogen therapy (ET) and estrogen plus progestin therapy (EPT) reduced fracture risk, neither reduced the risk of heart disease, and both increased the risk of stroke, deep vein thrombosis, and dementia. EPT, but not ET, increased breast cancer risk and reduced colon cancer risk. Differences between EPT and ET may reflect chance, baseline differences between the EPT and ET cohorts, or a progestin effect. Studies of younger women and lower HT doses with intermediate endpoints are beginning.

Early postmenopausal hormone therapy may prevent cognitive impairment later in life

OBJECTIVE

Estrogen deficiency has been implicated as a risk factor for cognitive impairment in elderly women, yet the role of hormone therapy (HT) to prevent this event remains controversial. The aim of this study was to investigate the impact of administration of HT for 2 to 3 years in the early postmenopausal years on the risk of cognitive impairment 5 to 15 years later.

DESIGN

We followed a group of 343 women who had received HT in randomized, placebo-controlled trials and were reexamined 5, 11, or 15 years after completion of therapy. Of these women, 261 received either HT or placebo for 2 to 3 years during the trials with no further hormone treatment until follow-up, and the remaining 82 women reported either prolonged or current use of HT at reexamination. Outcome of the study was cognitive function assessed by the short Blessed test that includes tests of orientation, concentration, and memory function on a scale of 0 to 28 (score > or =6 indicates cognitive impairment).

RESULTS

The mean age of participants at follow-up was 65 +/- 3 years. There was no difference in the mean cognitive scores between ever HT users and never users. For women who received 2 to 3 years of HT, the risk of cognitive impairment (cognitive score > or =6) was decreased by 64% (odds ratio [OR]: 0.36, 95% CI: 0.15-0.90; P = 0.03). A similar OR was found in long-term/current HT users. Adjustment for age, alcohol intake, current smoking, and education did not alter the results.

CONCLUSION

The results of the present study suggest that previous short-term HT administered in the early phase of the menopause may provide a long-term protection against cognitive impairment.

Reproductive events modify the effects of estrogen replacement therapy on cognition in healthy postmenopausal women

The question of whether estrogen replacement therapy (ERT) is beneficial to cognitive functioning in postmenopausal women has become controversial in the past several years. Early studies suggested that ERT improved cognitive functioning and decreased the risk of Alzheimer's disease, but recent studies have failed to find any benefit. However, studies have varied in terms of the age of participants, the estrogen preparation used, whether progesterone is administered concurrently, and the study design. The present study used a randomized, placebo-controlled design and a transdermal estrogen preparation composed of 17-beta estradiol. A neuropsychological battery was administered at baseline and after completion of the 10-week trial, and test scores were grouped into four composite scores using psychometric techniques. Baseline to follow-up change was analyzed using multiple regression techniques. Results indicate that while little overall beneficial effect of estrogen was found, years since menopause was significantly related to change in executive functioning in the estrogen but not the placebo group, such that more recently postmenopausal women demonstrated greater positive change than older women. Body mass index, a gross estimate of circulating estrogen, was significantly positively related to change in attentional and psychomotor processes regardless of treatment group, and to a weaker extent, verbal memory, but only in the estrogen-treated group. These results suggest that reproductive events and levels of endogenous estrogen are related to the clinical response to ERT, but larger studies with longer follow-up periods are needed to determine the strength of these effects.

Estrogen therapy and risk of cognitive decline: results from the Women's Estrogen for Stroke Trial (WEST)

OBJECTIVE

This study was undertaken to assess whether estrogen therapy (ET) reduces the risk of cognitive decline in women with cerebrovascular disease.

STUDY DESIGN

We conducted a randomized, double-blind trial of estradiol 17beta versus placebo for secondary stroke prevention in 664 postmenopausal women with a recent stroke or transient ischemic attack. The Mini-Mental State Examination (MMSE) and 5 domain measures were obtained at baseline and exit.

RESULTS

Among 461 women withdrawn alive without stroke, ET did not have a significant effect on cognitive measures after an average of 3 years (relative risk of MMSE decline: 0.74, 95% CI, 0.49-1.13). In women with normal MMSE at entry, estrogen was associated with less decline (relative risk, 0.46, 95% CI, 0.24-0.87).

CONCLUSION

In this study, estradiol did not have significant effects on cognitive measures. However, in women with normal function at baseline, there may be a benefit for ET in reducing the risk for cognitive decline.

Hormone therapy and risk for dementia: where do we go from here?

Prospective observational studies suggest that hormone therapy (HT) might confer protection against the development of Alzheimer's disease. In contrast, recent findings from the Women's Health Initiative Memory Study (WHIMS) indicated a doubling of the risk of all-cause dementia in women randomized to receive HT after age 64. The discrepancy between findings from observational studies and the WHIMS is commonly attributed to the lack of treatment bias in the randomized trial. However, there are other potentially important dfferences between the WHIMS and the observational studies. These include timing of initiation of HT and type of HT regimen used. The present review focuses on the clinical and basic science studies bearing on these clinically important issues. Additional clinical studies are needed to understand the external generalizability of the WHIMS results to populations of women for whom HT remains an indication.

Secondary prevention strategies in ischemic stroke: identification and optimal management of modifiable risk factors

The identification and treatment of modifiable Ischemic stroke risk factors, in addition to appropriate antithrombotic therapy, can reduce the likelihood of first or recurrent stroke, prevent long-term morbidity and mortality after first stroke or transient Ischemic attack, and lower health care costs. Long-term morbidity and mortality in patients with ischemic stroke includes patients with coronary artery disease. Therefore, in patients with ischemic stroke (especially those with carotid artery disease and lacunar disease), the goal is to prevent not only recurrent stroke but also coronary artery disease. Neurologists and general practitioners must be aware of the specific risk factors and recommendations for patients with ischemic stroke and apply the information systematically. We review known risk factors for ischemic stroke and current recommendations for treatment, focusing primarily on atherosclerotic risk factors as they apply to patients with stroke. In particular, recent data on hypertension and hyperlipidemia are described. In addition, we discuss the challenges in managing these risk factors and the potential strategies for overcoming them.

Ovarian hormones and cognition in the aged female rat: II. progesterone supplementation reverses the cognitive enhancing effects of ovariectomy

The authors hypothesized that the progesterone component of some hormone replacement therapies in women is detrimental to cognition. A previous study showed that ovariectomy (ovx) in aged rats enhanced spatial working memory and decreased elevated progesterone levels. The current study evaluated whether progesterone administration counteracts these cognitive enhancing effects of ovx. Aged sham and aged ovx rats given progesterone exhibited compromised learning of the working and reference memory components of the task, and made more working memory errors on the latter testing days compared with aged ovx rats not given progesterone. Results suggest that whereas ovx of the aged female rat enhances learning and the ability to handle numerous items of spatial working memory information, progesterone is detrimental to these aspects of performance. These findings may speak to studies in menopausal women which suggest that combination hormone therapies have a negative impact on cognition.

Hormone replacement therapy update: who should we be prescribing this to now?

PURPOSE OF REVIEW

To summarize results from the Women's Health Initiative trial and other recent randomized placebo-controlled trials of hormone replacement therapy, which fundamentally changed our understanding of its risks and benefits.

RECENT FINDINGS

The Women's Health Initiative study for the first time provided evidence of harmful effects of hormone replacement therapy on the cardiovascular system and also confirmed significantly increased risk of breast cancer which was previously documented in a metaanalysis. Most recent studies indicate a particularly harmful effect of combined estrogen/progestin regimens in terms of increased breast cancer risk.

SUMMARY

The effects of hormone replacement therapy on coronary heart disease, stroke, venous thromboembolism, breast cancer, gallbladder, diabetes, cognitive function, health-related quality of life, colorectal cancer, osteoporosis and menopausal symptoms are discussed briefly. The emphasis is on providing concise clinical guidelines for hormone replacement therapy use in new circumstances. We also discuss some alternative therapeutic modalities for women who have menopausal symptoms, but contraindications for hormone replacement therapy.

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.

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.

The impact of adjuvant therapy for breast cancer on cognitive function: current evidence and directions for research

Available evidence supports the hypothesis that adjuvant chemotherapy for breast cancer can produce cognitive deficits, and that these deficits may have a significant impact on patients' quality of life. Studies have generally compared the results of a variety of cognitive measures performed following treatment to standardized population-based norms or to cancer patients who received local therapy, rather than to the individual's baseline level of functioning. Several longitudinal studies are in progress or in the planning stages to better quantify and understand the incidence and impact of cognitive effects of adjuvant chemotherapy, and to identify possible susceptibility factors in subgroups. Although the neurocognitive changes appear to be subtle, there may be enough data to consider discussing the possibility of cognitive dysfunction as an adverse effect when assessing the risks and benefits of adjuvant chemotherapy. Likewise, as the aromatase inhibitors are increasingly given to larger numbers of women in the adjuvant setting, it will be important to understand the cognitive impact of estrogen deprivation. Finally, there is interest in examining supportive pharmacologic or behavioral measures that might prevent or decrease cognitive effects in this setting. Herein, the data on cognitive changes associated with chemotherapy for breast cancer, current and future research directions, as well as possible treatments are reviewed.

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.

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.