Influence of hormonal replacement therapy on the regional cerebral blood flow in postmenopausal women

Systematic review and meta-analysis of the effects of menopause hormone therapy on cognition

Introduction

Despite evidence from preclinical studies suggesting estrogen's neuroprotective effects, the use of menopausal hormone therapy (MHT) to support cognitive function remains controversial.

Methods

We used random-effect meta-analysis and multi-level meta-regression to derive pooled standardized mean difference (SMD) and 95% confidence intervals (C.I.) from 34 randomized controlled trials, including 14,914 treated and 12,679 placebo participants.

Results

Associations between MHT and cognitive function in some domains and tests of interest varied by formulation and treatment timing. While MHT had no overall effects on cognitive domain scores, treatment for surgical menopause, mostly estrogen-only therapy, improved global cognition (SMD=1.575, 95% CI 0.228, 2.921; P=0.043) compared to placebo. When initiated specifically in midlife or close to menopause onset, estrogen therapy was associated with improved verbal memory (SMD=0.394, 95% CI 0.014, 0.774; P=0.046), while late-life initiation had no effects. Overall, estrogen-progestogen therapy for spontaneous menopause was associated with a decline in Mini Mental State Exam (MMSE) scores as compared to placebo, with most studies administering treatment in a late-life population (SMD=-1.853, 95% CI -2.974, -0.733; P = 0.030). In analysis of timing of initiation, estrogen-progestogen therapy had no significant effects in midlife but was associated with improved verbal memory in late-life (P = 0.049). Duration of treatment >1 year was associated with worsening in visual memory as compared to shorter duration. Analysis of individual cognitive tests yielded more variable results of positive and negative effects associated with MHT.

Discussion

These findings suggest time-dependent effects of MHT on certain aspects of cognition, with variations based on formulation and timing of initiation, underscoring the need for further research with larger samples and more homogeneous study designs.

Systematic review and meta-analysis of the effects of menopause hormone therapy on risk of Alzheimer's disease and dementia

Introduction

Despite a large preclinical literature demonstrating neuroprotective effects of estrogen, use of menopausal hormone therapy (HT) for Alzheimer's disease (AD) risk reduction has been controversial. Herein, we conducted a systematic review and meta-analysis of HT effects on AD and dementia risk.

Methods

Our systematic search yielded 6 RCT reports (21,065 treated and 20,997 placebo participants) and 45 observational reports (768,866 patient cases and 5.5 million controls). We used fixed and random effect meta-analysis to derive pooled relative risk (RR) and 95% confidence intervals (C.I.) from these studies.

Results

Randomized controlled trials conducted in postmenopausal women ages 65 and older show an increased risk of dementia with HT use compared with placebo [RR = 1.38, 95% C.I. 1.16-1.64, p < 0.001], driven by estrogen-plus-progestogen therapy (EPT) [RR = 1.64, 95% C.I. 1.20-2.25, p = 0.002] and no significant effects of estrogen-only therapy (ET) [RR = 1.19, 95% C.I. 0.92-1.54, p = 0.18]. Conversely, observational studies indicate a reduced risk of AD [RR = 0.78, 95% C.I. 0.64-0.95, p = 0.013] and all-cause dementia [RR = .81, 95% C.I. 0.70-0.94, p = 0.007] with HT use, with protective effects noted with ET [RR = 0.86, 95% C.I. 0.77-0.95, p = 0.002] but not with EPT [RR = 0.910, 95% C.I. 0.775-1.069, p = 0.251]. Stratified analysis of pooled estimates indicates a 32% reduced risk of dementia with midlife ET [RR = 0.685, 95% C.I. 0.513-0.915, p = 0.010] and non-significant reductions with midlife EPT [RR = 0.775, 95% C.I. 0.474-1.266, p = 0.309]. Late-life HT use was associated with increased risk, albeit not significant [EPT: RR = 1.323, 95% C.I. 0.979-1.789, p = 0.069; ET: RR = 1.066, 95% C.I. 0.996-1.140, p = 0.066].

Discussion

These findings support renewed research interest in evaluating midlife estrogen therapy for AD risk reduction.

Brain volumetric changes in menopausal women and its association with cognitive function: a structured review

The menopausal transition has been proposed to put women at risk for undesirable neurological symptoms, including cognitive decline. Previous studies suggest that alterations in the hormonal milieu modulate brain structures associated with cognitive function. This structured review provides an overview of the relevant studies that have utilized MRI to report volumetric differences in the brain following menopause, and its correlations with the evaluated cognitive functions. We performed an electronic literature search using Medline (Ovid) and Scopus to identify studies that assessed the influence of menopause on brain structure with MRI. Fourteen studies met the inclusion criteria. Brain volumetric differences have been reported most frequently in the frontal and temporal cortices as well as the hippocampus. These regions are important for higher cognitive tasks and memory. Additionally, the deficit in verbal and visuospatial memory in postmenopausal women has been associated with smaller regional brain volumes. Nevertheless, the limited number of eligible studies and cross-sectional study designs warrant further research to draw more robust conclusions.

Ovarian steroid hormones: A long overlooked but critical contributor to brain aging and Alzheimer's disease

Ovarian hormones, particularly 17β-estradiol, are involved in numerous neurophysiological and neurochemical processes, including those subserving cognitive function. Estradiol plays a key role in the neurobiology of aging, in part due to extensive interconnectivity of the neural and endocrine system. This aspect of aging is fundamental for women's brains as all women experience a drop in circulating estradiol levels in midlife, after menopause. Given the importance of estradiol for brain function, it is not surprising that up to 80% of peri-menopausal and post-menopausal women report neurological symptoms including changes in thermoregulation (vasomotor symptoms), mood, sleep, and cognitive performance. Preclinical evidence for neuroprotective effects of 17β-estradiol also indicate associations between menopause, cognitive aging, and Alzheimer's disease (AD), the most common cause of dementia affecting nearly twice more women than men. Brain imaging studies demonstrated that middle-aged women exhibit increased indicators of AD endophenotype as compared to men of the same age, with onset in perimenopause. Herein, we take a translational approach to illustrate the contribution of ovarian hormones in maintaining cognition in women, with evidence implicating menopause-related declines in 17β-estradiol in cognitive aging and AD risk. We will review research focused on the role of endogenous and exogenous estrogen exposure as a key underlying mechanism to neuropathological aging in women, with a focus on whether brain structure, function and neurochemistry respond to hormone treatment. While still in development, this research area offers a new sex-based perspective on brain aging and risk of AD, while also highlighting an urgent need for better integration between neurology, psychiatry, and women's health practices.

Endogenous and Exogenous Estrogen Exposures: How Women's Reproductive Health Can Drive Brain Aging and Inform Alzheimer's Prevention

After advanced age, female sex is the major risk factor for late-onset Alzheimer's disease (AD), the most common cause of dementia affecting over 24 million people worldwide. The prevalence of AD is higher in women than in men, with postmenopausal women accounting for over 60% of all those affected. While most research has focused on gender-combined risk, emerging data indicate sex and gender differences in AD pathophysiology, onset, and progression, which may help account for the higher prevalence in women. Notably, AD-related brain changes develop during a 10-20 year prodromal phase originating in midlife, thus proximate with the hormonal transitions of endocrine aging characteristic of the menopause transition in women. Preclinical evidence for neuroprotective effects of gonadal sex steroid hormones, especially 17β-estradiol, strongly argue for associations between female fertility, reproductive history, and AD risk. The level of gonadal hormones to which the female brain is exposed changes considerably across the lifespan, with relevance to AD risk. However, the neurobiological consequences of hormonal fluctuations, as well as that of hormone therapies, are yet to be fully understood. Epidemiological studies have yielded contrasting results of protective, deleterious and null effects of estrogen exposure on dementia risk. In contrast, brain imaging studies provide encouraging evidence for positive associations between greater cumulative lifetime estrogen exposure and lower AD risk in women, whereas estrogen deprivation is associated with negative consequences on brain structure, function, and biochemistry. Herein, we review the existing literature and evaluate the strength of observed associations between female-specific reproductive health factors and AD risk in women, with a focus on the role of endogenous and exogenous estrogen exposures as a key underlying mechanism. Chief among these variables are reproductive lifespan, menopause status, type of menopause (spontaneous vs. induced), number of pregnancies, and exposure to hormonal therapy, including hormonal contraceptives, hormonal therapy for menopause, and anti-estrogen treatment. As aging is the greatest risk factor for AD followed by female sex, understanding sex-specific biological pathways through which reproductive history modulates brain aging is crucial to inform preventative and therapeutic strategies for AD.

Neuroendocrine Changes during Menopausal Transition

Menopause is the permanent cessation of menstrual cycles following the loss of ovarian follicular activity. Quality of life of postmenopausal woman is the result of a series of psychobiological transformations, that see in the reduction of sex hormones and steroids the etiopathogenetic determinant moment. Symptoms of menopause range from somatic side such as metabolic changes, increased cardiovascular disease, irregular vaginal bleeding, urogenital symptoms, vaginal dryness, osteoporosis and risk of bones fractures to changes of central nervous system as vasomotor symptoms, sleep disruption, mood changes, migraine, sexual dysfunctions. It is fundamental to know the mechanisms underlying changes in the central nervous system during menopause, related to hypoestrogenism, to be able to create appropriate target therapy for patients, improving their quality of life. In fact, the central nervous system is now one of the major targets of sex steroids that cannot be achieved disregard when dealing with the problem of choice of a particular type of MHT.

Cerebral blood flow, cerebrovascular reactivity and their influence on ventilatory sensitivity

NEW FINDINGS

What is the topic of this review? Cerebrovascular reactivity to CO₂ , which is a principal factor in determining ventilatory responses to CO₂ through the role reactivity plays in determining cerebral extra- and intracellular pH. What advances does it highlight? Recent animal evidence suggests central chemoreceptor vasculature may demonstrate regionally heterogeneous cerebrovascular reactivity to CO₂ , potentially as a protective mechanism against excessive CO₂ washout from the central chemoreceptors, thereby allowing ventilation to reflect the systemic acid-base balance needs (respiratory changes in P aC O 2 ) rather than solely the cerebral needs. Ventilation per se does not influence cerebrovascular reactivity independent of changes in P aC O 2 .

ABSTRACT

Alveolar ventilation and cerebral blood flow are both predominantly regulated by arterial blood gases, especially arterial P C O 2 , and so are intricately entwined. In this review, the fundamental mechanisms underlying cerebrovascular reactivity and central chemoreceptor control of breathing are covered. We discuss the interaction of cerebral blood flow and its reactivity with the control of ventilation and ventilatory responsiveness to changes in P C O 2 , as well as the lack of influence of ventilation itself on cerebrovascular reactivity. We briefly summarize the effects of arterial hypoxaemia on the relationship between ventilatory and cerebrovascular response to both P C O 2 and P O 2 . We then highlight key methodological considerations regarding the interaction of reactivity and ventilatory sensitivity, including the following: regional heterogeneity of cerebrovascular reactivity; a pharmacological approach for the reduction of cerebral blood flow; reactivity assessment techniques; the influence of mean arterial blood pressure; and sex-related differences. Finally, we discuss ventilatory and cerebrovascular control in the context of high altitude and congestive heart failure. Future research directions and pertinent questions of interest are highlighted throughout.

Integrative cardiovascular control in women: Regulation of blood pressure, body temperature, and cerebrovascular responsiveness

Over the past several decades, it has become increasingly clear that women have distinct cardiovascular profiles compared to men. In this review, our goal is to provide an overview of the literature regarding the influences of female sex and reproductive hormones (primarily estradiol) on mechanisms of cardiovascular control relevant to regulation of blood pressure, body temperature, and cerebral blood flow. Young women tend to have lower resting blood pressure compared with men. This sex difference is reversed at menopause, when women develop higher sympathetic nerve activity and the risk of systemic hypertension increases sharply as postmenopausal women age. Vascular responses to thermal stress, including cutaneous vasodilation and vasoconstriction, are also affected by reproductive hormones in women, where estradiol appears to promote vasodilation and heat dissipation. The influence of reproductive hormones on cerebral blood flow and sex differences in the ability of the cerebral vasculature to increase its blood flow (cerebrovascular reactivity) are relatively new areas of investigation. Sex and hormonal influences on integrative blood flow regulation have further implications during challenges to physiological homeostasis, including exercise. We propose that increasing awareness of these sex-specific mechanisms is important for optimizing health care and promotion of wellness in women across the life span.

Variability of physiological brain perfusion in healthy subjects - A systematic review of modifiers. Considerations for multi-center ASL studies

Quantitative measurements of brain perfusion are influenced by perfusion-modifiers. Standardization of measurement conditions and correction for important modifiers is essential to improve accuracy and to facilitate the interpretation of perfusion-derived parameters. An extensive literature search was carried out for factors influencing quantitative measurements of perfusion in the human brain unrelated to medication use. A total of 58 perfusion modifiers were categorized into four groups. Several factors (e.g., caffeine, aging, and blood gases) were found to induce a considerable effect on brain perfusion that was consistent across different studies; for other factors, the modifying effect was found to be debatable, due to contradictory results or lack of evidence. Using the results of this review, we propose a standard operating procedure, based on practices already implemented in several research centers. Also, a theory of 'deep MRI physiotyping' is inferred from the combined knowledge of factors influencing brain perfusion as a strategy to reduce variance by taking both personal information and the presence or absence of perfusion modifiers into account. We hypothesize that this will allow to personalize the concept of normality, as well as to reach more rigorous and earlier diagnoses of brain disorders.

Correlation between allopregnanolone levels and depressive symptoms during late menopausal transition and early postmenopause

OBJECTIVES

This observational, cross-sectional study included 140 women with climacteric symptoms. The aim of the study was to evaluate the correlation between the presence and severity of depressive symptoms and allopregnanolone levels in women during late menopausal transition and early postmenopause.

METHODS

The study group was divided into two groups: 45 women in late menopausal transition and 95 early postmenopausal women. We evaluated Kupperman index, Hamilton scale and serum follicle-stimulating hormone, luteinizing hormone, 17β-estradiol, prolactin, total testosterone, dehydroepiandrosterone sulfate and allopregnanolone levels.

RESULTS

We found that serum allopregnanolone concentration was lower in early postmenopausal women compared to women in late menopausal transition; that there was a correlation between serum allopregnanolone levels in early postmenopausal women and time since last menstruation, intensity of climacteric symptoms, and intensity of depression symptoms and that there was a correlation between serum allopregnanolone levels and several depression symptoms presence (shallow sleep and symptoms of the digestive tract in women during late menopause transition; feelings of guilt, sleep disorders and general somatic symptoms in early postmenopausal women).

CONCLUSION

We concluded that reproductive aging is characterized by a reduction of allopregnanolone circulating levels that correlate to Hamilton depression index in early postmenopause and presence of specific depressive symptoms during late menopausal transition and early postmenopause.

Cerebral blood flow regulation in women across menstrual phase: differential contribution of cyclooxygenase to basal, hypoxic, and hypercapnic vascular tone

In healthy young women, basal cerebral blood flow (CBF) and cerebrovascular reactivity may change across the menstrual cycle, but mechanisms remain untested. When compared with the early follicular phase of the menstrual cycle, we hypothesized women in late follicular phase would exhibit: 1) greater basal CBF, 2) greater hypercapnic increases in CBF, 3) greater hypoxic increases in CBF, and 4) increased cyclooxygenase (COX) signaling. We measured middle cerebral artery velocity (MCAv, transcranial Doppler ultrasound) in 11 healthy women (23 ± 1 yr) during rest, hypoxia, and hypercapnia. Subjects completed four visits: two during the early follicular (∼day 3) and two during the late follicular (∼day 14) phases of the menstrual cycle, with and without COX inhibition (oral indomethacin). Isocapnic hypoxia elicited an SPO2 = 90% and SPO2 = 80% for 5 min each. Separately, hypercapnia increased end-tidal CO2 10 mmHg above baseline. Cerebral vascular conductance index (CVCi = MCAv/MABP·100, where MABP is mean arterial blood pressure) was calculated and a positive change reflected vasodilation (ΔCVCi). Basal CVCi was greater in the late follicular phase (P < 0.001). Indomethacin decreased basal CVCi (∼37%) and abolished the phase difference (P < 0.001). Hypoxic ΔCVCi was similar between phases and unaffected by indomethacin. Hypercapnic ΔCVCi was similar between phases, and indomethacin decreased hypercapnic ΔCVCi (∼68%; P < 0.001) similarly between phases. In summary, while neither hypercapnic nor hypoxic vasodilation is altered by menstrual phase, increased basal CBF in the late follicular phase is fully explained by a greater contribution of COX. These data provide new mechanistic insight into anterior CBF regulation across menstrual phases and contribute to our understanding of CBF regulation in women.

Enhanced Neuroactivation during Working Memory Task in Postmenopausal Women Receiving Hormone Therapy: A Coordinate-Based Meta-Analysis

BACKGROUND AND AIM

Hormone therapy (HT) has long been thought beneficial for controlling menopausal symptoms and human cognition. Studies have suggested that HT has a positive association with working memory, but no consistent relationship between HT and neural activity has been shown in any cognitive domain. The purpose of this meta-analysis was to assess the convergence of findings from published randomized control trials studies that examined brain activation changes in postmenopausal women.

METHODS

A systematic search for fMRI studies of neural responses during working memory tasks in postmenopausal women was performed. Studies were excluded if they were not treatment studies and did not contain placebo or blank controls. For the purpose of the meta-analysis, 8 studies were identified, with 103 postmenopausal women taking HT and 109 controls.

RESULTS

Compared with controls, postmenopausal women who took HT increased activation in the left frontal lobe, including superior frontal gyrus (BA 8), right middle frontal gyrus (BA 9), anterior lobe, paracentral lobule (BA 7), limbic lobe, and anterior cingulate (BA 32). Additionally, decreased activation is noted in the right limbic lobe, including parahippocampal gyrus (BA 28), left parietal lobe, and superior parietal lobule (BA 7). All regions were significant at p ≤ 0.05 with correction for multiple comparisons.

CONCLUSION

Hormone treatment is associated with BOLD signal activation in key anatomical areas during fMRI working memory tasks in healthy hormone-treated postmenopausal women. A positive correlation between activation and task performance suggests that hormone use may benefit working memory.

Functional and molecular neuroimaging of menopause and hormone replacement therapy

The level of gonadal hormones to which the female brain is exposed considerably changes across the menopausal transition, which in turn, is likely to be of great relevance for neurodegenerative diseases and psychiatric disorders. However, the neurobiological consequences of these hormone fluctuations and of hormone replacement therapy in the menopause have only begun to be understood. The present review summarizes the findings of thirty-five studies of human brain function, including functional magnetic resonance imaging, positron and single-photon computed emission tomography studies, in peri- and postmenopausal women treated with estrogen, or estrogen-progestagen replacement therapy. Seven studies using gonadotropin-releasing hormone agonist intervention as a model of hormonal withdrawal are also included. Cognitive paradigms are employed by the majority of studies evaluating the effect of unopposed estrogen or estrogen-progestagen treatment on peri- and postmenopausal women's brain. In randomized-controlled trials, estrogen treatment enhances activation of fronto-cingulate regions during cognitive functioning, though in many cases no difference in cognitive performance was present. Progestagens seems to counteract the effects of estrogens. Findings on cognitive functioning during acute ovarian hormone withdrawal suggest a decrease in activation of the left inferior frontal gyrus, thus essentially corroborating the findings in postmenopausal women. Studies of the cholinergic and serotonergic systems indicate these systems as biological mediators of hormonal influences on the brain. More, hormonal replacement appears to increase cerebral blood flow in several cortical regions. On the other hand, studies on emotion processing in postmenopausal women are lacking. These results call for well-powered randomized-controlled multi-modal prospective neuroimaging studies as well as investigation on the related molecular mechanisms of effects of menopausal hormonal variations on the brain.

The cerebellum as a target for estrogen action

This review focuses on the effects of estrogens upon the cerebellum, a brain region long ignored as a site of estrogen action. Highlighted are the diverse effects of estradiol within the cerebellum, emphasizing the importance of estradiol signaling in cerebellar development, modulation of synaptic neurotransmission in the adult, and the potential influence of estrogens on various health and disease states. We also provide new data, consistent with previous studies, in which locally synthesized estradiol modulates cerebellar glutamatergic neurotransmission, providing one underlying mechanism by which the actions of estradiol can affect this brain region.

Clinical Efficacy of EH0202, a Kampo Formula, on the Health of Middle-Aged Women

To investigate the clinical effects of EH0202, a Japanese herbal supplement, on the menopausal symptoms and physical status of peri- and post-menopausal women. Thirty-two post-menopausal women (53.0±5.1 years) presented with menopausal complaints were enrolled in the clinical study. Patients were administered an herbal supplement, EH0202 (6 g/day for 6 months), and were assessed for improvement of their overall symptoms using the Greene Climacteric Scale and the Visual Analog Scale (VAS). Blood pressure, skin surface blood flow and plasma lipid profiles were measured before and 1, 3 and 6 months after EH0202 administration. There was a significant decrease in the climacteric scale score (P<0.001) and VAS (P<0.0001) after 6 months of EH0202 treatment. There was a significant decrease in systolic (P<0.001) and diastolic (P<0.05) blood pressure, and a significant decrease in facial skin surface blood flow (P<0.05) after 3 months of EH0202 administration. We observed a significant decrease in plasma TG and LDL-cholesterol concentrations after 3 months of EH0202 administration (P<0.05). EH0202 (MACH) reduced blood pressure, excess facial skin blood flow (flushing) and abnormal lipid levels, as well as clinically improved menopausal symptoms in post-menopausal women. In post-menopausal women, this product appears to help maintain normal biological function and improves quality of life.

Polymorphisms of the estrogen receptor alpha (ESR1) gene and the risk of Alzheimer's disease in a southern Chinese community

BACKGROUND

Alzheimer's disease (AD) is a neurodegenerative disease with a higher prevalence in women. Expression of estrogen receptor 1 (ESR1) gene has been identified throughout the brain. Owing to the putative neuroprotective effects of estrogen, estrogen receptor gene is a potential candidate modulating the development of AD. Preliminary associations between two polymorphisms of ESR1 (PvuII and XbaI) gene and AD have been reported.

METHODS

In this study, 16 single nucleotide polymorphisms (SNPs) of the ESR1 gene (including four commonly studied ESR1 SNPs and 12 other tagging SNPs selected from the HapMap database) were investigated to further evaluate the association between ESR1 polymorphisms and the risk of AD in the Chinese population.

RESULTS

A total of 233 Chinese AD patients and 245 age-matched elderly control subjects were recruited. Genetic associations were analyzed by chi-square test and interaction effect was analysed by logistic regression analysis. Five SNPs (clustered between intron 3 and intron 7) were associated with the risk of AD (p-value ranges from 0.001 to 0.035); another two SNPs (located on exon 2 and intron 2) were shown to modulate the age-at-onset (AAO) in AD (p-value = 0.036 and 0.011).

CONCLUSIONS

ESR1 gene polymorphisms may be associated with the AAO in AD. The present results provided information for possible associations between certain polymorphisms of ESR1 gene and the risk of AD.

Enhanced neuroactivation during verbal memory processing in postmenopausal women receiving short-term hormone therapy

OBJECTIVE

To study the effects of hormone therapy on brain activation patterns during verbal memory in postmenopausal women.

DESIGN

A randomized, double-blind placebo-controlled cross-over study was performed.

SETTING

A tertiary care university medical center.

PATIENT(S)

Ten healthy postmenopausal women (age range 56-60 years) were recruited from the local community.

INTERVENTION(S)

Women were randomized to the order they received combined hormone therapy, 5 microg of ethinyl E(2) and 1 mg of norethindrone acetate, and placebo. Volunteers received hormone therapy or placebo for 4 weeks, followed by a 1-month washout period, and then received the other treatment for 4 weeks. A functional magnetic resonance imaging (fMRI) was performed at the end of each 4-week treatment using a verbal memory task.

MAIN OUTCOME MEASURE(S)

Brain activation patterns were compared between hormone therapy and placebo.

RESULT(S)

Hormone therapy was associated with increased activation in the left middle/superior frontal cortex (BA 6,9), medial frontal cortex and dorsal anterior cingulate (BA 24,32), posterior cingulate (BA 6), and left inferior parietal cortex (BA 40) during memory encoding. All regions were significant with correction for multiple comparisons.

CONCLUSION(S)

Hormone therapy increased neural activation in frontal and parietal areas in postmenopausal women during a verbal memory task.

Reduced frontal perfusion in depressed postmenopausal women: a SPECT study with WCST

OBJECTIVES

To investigate frontal cerebral blood flow (CBF) in depressed postmenopausal women and its relation to cognitive function and the severity of depressive symptoms.

METHODS

Regional CBF of 20 unmedicated depressed postmenopausal women was measured using Tc-99m HMPAO SPECT, both at rest and during frontal activation using the Wisconsin card sorting test (WCST). Frontal CBF was semi-quantified by comparing the radioactivity in the prefrontal region to the cerebellum (F/C ratio). We measured the severity of the symptoms of depression using the hospital anxiety and depression scale (HADS) and cognitive function using the mini-mental status examination (MMSE).

RESULTS

At rest, there was no difference in frontal CBF between patients with moderate or severe (HADS> or =11) and patients with mild depressive symptoms (HADS<11). During the WCST, however, the HADS> or =11 group did not score as well as the HADS<11 group (P=0.03). The changes in F/C ratios were inversely correlated with HADS scores (r=-0.43, P=0.05) and positively correlated with MMSE scores (r=0.58, P=0.004). After adjusting for age, F/C ratios were significantly correlated with MMSE (P=0.002), but not with HADS scores.

CONCLUSIONS

Frontal CBF did not increase in postmenopausal women with moderate/severe symptoms of depression during the WCST activation task, and reduced frontal CBF was related to the impairment of cognitive function. The combination of the functional activation test and SPECT imaging powerfully revealed this functional disease, which remains undetectable using more common baseline measurements.

Cerebral blood flow is increased during controlled ovarian stimulation

Estrogen appears to enhance cerebral blood flow (CBF). An association between CBF and physiologically altered hormonal levels due to menstrual cycle, menopause, or exogenous manipulations such as ovariectomy or hormone replacement therapy has been demonstrated. The purpose of this study was to determine the association between ovarian stimulation and CBF in vivo by measuring blood flow in the internal carotid artery (ICA) after pituitary suppression and during controlled ovarian stimulation in women undergoing in vitro fertilization treatment cycles. ICA volume flows were measured by angle-independent dual-beam ultrasound Doppler in 12 women undergoing controlled ovarian stimulation. Measurements were performed after pituitary/ovarian suppression, in the late follicular phase, and at midluteal phase. Blood flow in the ICA increased by 22.2% and 32% in the late follicular and midluteal phases compared with the respective values obtained during ovarian suppression (P < 0.0005 and P < 0.0001, respectively). There was a significant correlation between increments in estrogen levels and increments in CBF when the late follicular phase was compared with the ovarian suppression period (r = 0.8, P < 0.001). Mean blood flow velocity significantly increased (by 15.7% and 16.9%, respectively) and cerebral vascular resistance significantly decreased (by 17.6% and 26.5%) during the late follicular and midluteal phases compared with respective measures during ovarian suppression. There was a significant correlation between an increase in estrogen levels and a decrease in cerebral vascular resistance when the late follicular phase was compared with the ovarian suppression period (r = -0.6, P < 0.05). These changes imply sex hormone-associated intracranial vasodilation leading to increased CBF during controlled ovarian stimulation.

Evaluation of hormone replacement therapy which may have an adrenomedullin-mediated protective effect on cardiovascular disorders

BACKGROUND AND AIMS

This study aimed to determine whether there is an adrenomedullin (AM)-mediated protective effect of postmenopausal estrogen/progestin therapy (HRT) against cardiovascular disorders.

METHODS

A total of 22 post-menopausal women without hysterectomy undergoing postmenopausal symptoms (aged 43-52) were treated with conjugated equine estrogen (0.625 mg/die) plus medroxyprogesterone acetate (2.5 mg/die) for six months. The flow velocity of the right middle cerebral artery [measured as resistance index (RI) and pulsatility index (PI)], plasma levels of adrenomedullin and endothelin- 1 (ET-1), mean baseline ratio of AM to ET-1, and lipid profiles were assessed before and after HRT.

RESULTS

A statistically significant difference was found for triglycerides, total cholesterol, AM/ET-1 ratio and right middle cerebral artery PI (p<0.05), without any significant differences in HDL, LDL, AM, ET-1, systolic blood pressure, diastolic blood pressure, a right middle cerebral artery RI (p>0.05) between pre- and post- HRT.

CONCLUSIONS

Adrenomedullin may be added to other vasoactive peptides as a new potential candidate for HRT-mediated vascular protection. The ratio of AM/ET-1 vs AM or ET-1 alone may be a useful biological marker of this protection.

Impact of combined estradiol and norethindrone therapy on visuospatial working memory assessed by functional magnetic resonance imaging

CONTEXT

Hormones regulate neuronal function in brain regions critical to cognition; however, the cognitive effects of postmenopausal hormone therapy are controversial.

OBJECTIVE

The goal was to evaluate the effect of postmenopausal hormone therapy on neural circuitry involved in spatial working memory.

DESIGN

A randomized, double-blind, placebo-controlled crossover study was performed.

SETTING

The study was performed in a tertiary care university medical center.

PARTICIPANTS

Ten healthy postmenopausal women of average age 56.9 yr were recruited.

INTERVENTIONS

Volunteers were randomized to the order they received hormone therapy (5 microg ethinyl estradiol and 1 mg norethindrone acetate). Subjects received hormone therapy or placebo for 4 wk, followed by a 1-month washout period with no medications, and then received the other treatment for 4 wk. At the end of each 4-wk treatment period, a functional magnetic resonance imaging study was performed using a nonverbal (spatial) working memory task, the Visual Delayed Matching to Sample task.

MAIN OUTCOME MEASURE

The effects of hormone therapy on brain activation patterns were compared with placebo.

RESULTS

Compared with the placebo condition, hormone therapy was associated with a more pronounced activation in the prefrontal cortex (BA 44 and 45), bilaterally (P < 0.001).

CONCLUSIONS

Hormone therapy was associated with more effective activation of a brain region critical in primary visual working memory tasks. The data suggest a functional plasticity of memory systems in older women that can be altered by hormones.

Influence of sex steroid hormones on cerebrovascular function

The cerebral vasculature is a target tissue for sex steroid hormones. Estrogens, androgens, and progestins all influence the function and pathophysiology of the cerebral circulation. Estrogen decreases cerebral vascular tone and increases cerebral blood flow by enhancing endothelial-derived nitric oxide and prostacyclin pathways. Testosterone has opposite effects, increasing cerebral artery tone. Cerebrovascular inflammation is suppressed by estrogen but increased by testosterone and progesterone. Evidence suggests that sex steroids also modulate blood-brain barrier permeability. Estrogen has important protective effects on cerebral endothelial cells by increasing mitochondrial efficiency, decreasing free radical production, promoting cell survival, and stimulating angiogenesis. Although much has been learned regarding hormonal effects on brain blood vessels, most studies involve young, healthy animals. It is becoming apparent that hormonal effects may be modified by aging or disease states such as diabetes. Furthermore, effects of testosterone are complicated because this steroid is also converted to estrogen, systemically and possibly within the vessels themselves. Elucidating the impact of sex steroids on the cerebral vasculature is important for understanding male-female differences in stroke and conditions such as menstrual migraine and preeclampsia-related cerebral edema in pregnancy. Cerebrovascular effects of sex steroids also need to be considered in untangling current controversies regarding consequences of hormone replacement therapies and steroid abuse.

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.

Effect of Aerodiol administration on cerebral blood flow volume in postmenopausal women

OBJECTIVE

The aim of the study was to evaluate the acute effect of the intranasal 17beta-estradiol (Aerodiol, Servier, Chambray-les-Tours, France) administration on cerebral blood flow (CBF) volume.

METHODS

Eighteen healthy women who had been natural postmenopausal for at least 1 year were enrolled in the study. We conducted an experimental, randomized, placebo-controlled, crossover, double-blinded study of the acute effect of 17beta-estradiol on the internal carotid artery (ICA), vertebral artery (VA) and, CBF volume using color duplex sonography.

RESULTS

There were significant increases in the ICA, VA flow volumes and CBF volume after 17beta-estradiol administration compared to placebo measurements. However, there was no statistically significant difference in flow velocities or pulsatility indices.

CONCLUSION

Nasal 17beta-estradiol administration in postmenopausal women causes significant increases in CBF volume due to its vasodilatatory effect on ICA and VA.

Estrogen restores postischemic sensitivity to the thromboxane mimetic U46619 in rat pial artery

The objectives of the study were to (1) characterize the dose-response relationship to the TXA2 analog, U46619 (0.01, 0.1, and 1 micromol/L) after global cerebral ischemia, (2) determine whether chronic 17beta-estradiol (E2) replacement alters this relationship, and (3) determine if E2's mechanisms are transduced through cognate estrogen receptors. Rats were assigned to five groups (n=6): placebo-implanted ovariectomized (OVX) females, OVX plus chronic E2 (CE), OVX plus acute E2 (AE), OVX plus chronic E2 plus the estrogen receptor inhibitor ICI 182,780 (CEI), and OVX plus acute E2 plus ICI 182,780 (AEI). Rats were anesthetized, intubated, cannulated (femoral artery and vein), fitted with a closed cranial window, and subjected to 15-min reversible forebrain ischemia (4-vessel occlusion, 4-VO) and 60 mins of reperfusion. Arterial blood gases, intrawindow pressure, and temperature were controlled. Vessel diameter was measured before and 5 mins after superfusion of each concentration of U46619. Compared with preischemic responses, contractile response to U46619 was depressed at all concentrations after ischemia in the OVX group. In the chronic E2 and acute E2 groups, contractile response to 1 micromol/L of U46619 was normalized to near baseline values. However, in the CEI and the AEI groups, postischemic vasoconstriction was similar to that observed in the OVX rats. We conclude that E2 targets the cerebral microvasculature to preserve postischemic pial artery reactivity and that the effect is receptor mediated. Restoration of normal constriction to vascular agonists may be an important mechanism by which E2 protects the vasculature and diminishes tissue damage after ischemia.

Estrogen influences cocaine-induced blood oxygen level-dependent signal changes in female rats

We investigated the effect of estrogen on cocaine-induced brain activity using blood oxygen level-dependent (BOLD) magnetic resonance imaging. Ovariectomized (Ovx) rats without estrogen and Ovx rats with estrogen (Ovx+E) were given a single saline or cocaine injection (15 mg/kg, i.p.) for 5 d. After 7 d of withdrawal from injections, rats were challenged with cocaine during functional imaging. Acute cocaine administration produced positive BOLD activation in the prefrontal cortex, nucleus accumbens, striatum, ventral tegmental area, and hippocampus, among other brain regions. Positive BOLD signal changes were lower in Ovx+E than in Ovx rats. With repeated cocaine administration, Ovx+E rats showed enhanced BOLD signal changes in the nucleus accumbens, ventral tegmental area, and hippocampus compared with acutely treated animals. Our results indicate that estrogen influences the effects of acute and repeated cocaine administration on BOLD signal changes. The data suggest that in females with estrogen, cocaine-induced neuronal activity is enhanced after repeated cocaine administration. It is possible that the actions of estrogen within the aforementioned brain regions potentiate the behavioral response to cocaine observed in female rats.