Estradiol for treatment-resistant schizophrenia: a large-scale randomized-controlled trial in women of child-bearing age

Many women with schizophrenia remain symptomatic despite optimal use of current therapies. While previous studies suggest that adjunctive oestrogen therapy might be effective, large-scale clinical trials are required before clinical applications are possible. This study is the first large-scale randomized-controlled trial in women with treatment-resistant schizophrenia. This Definitive Oestrogen Patch Trial was an 8-week, three-arm, double-blind, randomized-controlled trial conducted between 2006 and 2011. The 183 female participants were aged between 18 and 45 (mean = 35 years), with schizophrenia or schizoaffective disorder and ongoing symptoms of psychosis (Positive and Negative Syndrome Scale, PANSS score>60) despite a stable dose of antipsychotic medication for at least 4 weeks. Mean duration of illness was more than 10 years. Participants received transdermal estradiol 200 μg, transdermal estradiol 100 μg or an identical placebo patch. For the 180 women who completed the study, the a priori outcome measure was the change in PANSS score measured at baseline and days 7, 14, 28 and 56. Cognition was assessed at baseline and day 56 using the Repeatable Battery of Neuropsychological Status. Data were analysed using latent growth curve modelling. Both estradiol groups had greater decreases in PANSS positive, general and total symptoms compared with the placebo group (P<0.01), with a greater effect seen for 200 μg than 100 μg estradiol. The largest effect size was for the positive subscale of PANSS in the estradiol 200 μg treatment group (effect size 0.44, P<0.01). This study shows estradiol is an effective and clinically significant adjunctive therapy for women with treatment-resistant schizophrenia, particularly for positive symptoms.

Special biological issues in the management of women with schizophrenia

Schizophrenia is a debilitating and pervasive mental illness with devastating effects on psychological, cognitive and social wellbeing, and for which current treatment options are far from ideal. Gender differences and the influence of the female reproductive life cycle on the onset, course and symptoms of schizophrenia and the discovery of estrogen's remarkable psychoprotective properties in animal models led to the proposal of the 'estrogen protection hypothesis' of schizophrenia. This has fueled the recent successful investigation of estradiol as a potential adjuvant therapeutic agent in the management of schizophrenia in women. This review explains the scientific rationale behind the estrogen hypothesis and how it can be clinically utilized to address concerns unique to the care of women with schizophrenia.

Efficacy of porcine placental extract on climacteric symptoms in peri- and postmenopausal women

OBJECTIVES

Injections of human placental extract have long been used to treat menopausal symptoms. Recently, porcine placental extract (PPE), an oral supplement, has been developed for this purpose. The aim of this study was to assess whether PPE has an impact on climacteric symptoms in perimenopausal and postmenopausal women.

METHODS

Seventy-six women with climacteric symptoms were enrolled into this open-label, randomized, controlled study. The control group (n = 38) underwent 24 weeks of open treatment with Toki-shakuyaku-san (TJ23), an oral herbal remedy used to alleviate climacteric symptoms. The PPE group (n = 38) received three capsules of PPE/day orally for the initial 12 weeks and six capsules/day for the next 12 weeks. Climacteric symptoms were evaluated in both groups using the Simplified Menopausal Index (SMI) score, Zung's Self-Rating Depression Scale (ZSDS) and the Spielberger State-Trait Anxiety Inventory (STAI) before commencing treatment, after 12 weeks of treatment and on completion of treatment.

RESULTS

Treatment with PPE was significantly (p < 0.01) more effective in reducing the SMI, ZSDS and STAI measures at 12 and 24 weeks than TJ23 treatment alone. Treatment with PPE was also significantly effective (p < 0.01) in reducing the subscale scores of the SMI for items such as hot flushes, insomnia, irritability, depression, fatigue and joint pain. PPE treatment had no significant adverse effects.

CONCLUSION

Oral PPE treatment is another possible option for treating perimenopausal and postmenopausal women with climacteric symptoms.

Cognitive Effects of Systemic Therapy in Patients with Breast Cancer

Many patients with breast cancer complain about concentration and memory problems in connection with systemic therapy. A number of studies investigating the possible decrease in cognitive abilities were published in the 1980s. Numerous studies showed impaired performance of patients receiving chemotherapy. The results concerning profile, extent, and duration of cognitive impairments are, however, non-uniform. Increasing interest has been focused in the last years on effects of endocrine therapy on cognitive capacity - especially concerning the effects of the almost complete estrogen depletion caused by aromatase inhibitors. Often, the published studies did not evaluate particular effects of endocrine therapy without considering interference of cytotoxic treatment. Furthermore, the different endocrine medications (antiestrogens vs. aromatase inhibitors) were usually not regarded separately despite different mechanisms of action. Hence, the results of past investigations are also controversial. In the future, prospective trials with larger samples are necessary. Differentiation between chemotherapy and endocrine therapy is essential. Likewise, different types of endocrine therapy should be examined separately.

The potential role of glucose transport changes in hot flash physiology: a hypothesis

PURPOSE

The purpose of this article is to detail a novel hypothesis regarding the role of changes in brain glucose delivery in menopausal hot flashes.

ORGANIZING FRAMEWORK

The impaired glucose delivery hypothesis of menopausal hot flashes is presented as a potential model of hot flash physiology. As foundational to the hypothesis, brain glucose physiology, specifically neurobarrier coupling, is presented in detail. With brain activation, glucose needs immediate increase; additional glucose is supplied through increased production of glucose transporter 1 (GLUT1) at the blood-brain barrier (BBB) and through vasodilation. Estrogen is important to this system in stimulating production of GLUT1. As estrogen declines at menopause, upregulation of GLUT1 is less efficient. As a consequence, neurobarrier coupling overcompensates with an excess neurovascular response, or a hot flash. Research supporting this hypothesis is briefly reviewed and new questions raised are reviewed.

CONCLUSIONS

The impaired glucose hypothesis of menopausal hot flashes proposes an inadequate neurobarrier response to neurometabolic stimulation as estrogen declines, resulting in additional neurometabolic stimulation with consequent neurovascular stimulation. In this model, the menopausal woman has diminished ability to respond to fluctuations in blood glucose over the course of the day, which results in hot flashes as a counter-regulatory response. This perspective accounts for observed physiological changes that have not been previously detailed. New research directions are identified.

Menopausal Hot Flashes and Development of Cognitive Impairment

Hot flashes have a negative influence on the quality of life in hypogonadal women. There seem to be many regulators of hot flashes that add to the complexity of these profound vasomotor symptoms. In this paper, focus is placed on selected factors that may be involved in the relationship between hot flashes and cognitive status. During the hypogonadal state, the brain becomes relatively deprived of glucose. Hot flashes were found to be associated with transient inadequacies in brain levels of glucose. Neuroglucopenia was shown to initiate a cascade of immediate and delayed reactions leading to neuronal damage. Estrogen is known to diminish neuroglucopenia. In a pilot study on postmenopausal women, it was observed that cognitive performance of women who reported having hot flashes during their menopausal years was better than in women who did not experience hot flashes. It is hypothesized that a hot flash triggers a counterregulatory mechanism of the central nervous system to the insufficiency of glucose delivery to the brain and may have a beneficial effect on cognitive health in postmenopausal women. Possible therapeutic implications of this hypothesis are discussed in the light of current knowledge.

Menopausal hot flash frequency changes in response to experimental manipulation of blood glucose

OBJECTIVE

Although a majority of women (80%) at menopause experience hot flashes, the symptoms' physiological trigger has yet to be identified. To determine the relationship between glucose availability and hot flashes in menopausal women, hot flash frequency was compared between intervals while the subjects were fasting and/or infusing in a sample of menopausal women (38-55 years of age).

DESIGN

An experimental study was conducted in 10 postmenopausal women taking hormone therapy (HT) between the ages of 38 and 55. Following a clinic visit to screen for general health and absence of diabetes, HT participants were asked to stop the medication for 7 to 10 days and to maintain a diary of hot flash frequency. When hot flashes were experienced at least four times per day in a consecutive 3-day period, participants were admitted to the General Clinical Research Center for a 30-hour experimental protocol, including frequent blood sampling and two experimental periods of intravenous infusion of glucose or normal saline. Blood glucose levels were manipulated to provide conditions of postprandial versus fasting states.

RESULTS

There was a significant reduction in the incidence of hot flashes during the experimental elevation of glucose concentrations (130 to 140 mg/dl) compared to the fasting state (<110 mg/dl) (t= -2.4, df= 9, p=.04).

CONCLUSIONS

Conditions of fasting may stimulate the trigger mechanism for menopausal hot flashes.

What we know about managing menopausal hot flashes: navigating without a compass

Hot flashes and night sweats are frequently experienced as the cardinal symptoms of menopause. However, their physiological basis has not been explained; nor have any potential risks been explored. Current knowledge and theoretical perspectives regarding hot flashes will be presented and contrasted with evidence for an emerging hypothesis of altered brain glucose availability as the hot flash trigger. Perspectives regarding hormone therapy and alternative therapies for treatment of hot flashes will be presented and directions for future research reviewed.

The role of sex hormones in psychopathology: focus on schizophrenia

The example of schizophrenia is used to illustrate how sex hormones affect the presentation of illness and its treatment. Organization and activation effects of hormones are explained, and behavior is shown to result from a complex interplay of hormones, brain mechanisms, and social pressures. Sex differences in schizophrenia (in onset age, symptoms, antipsychotic, and other treatment) are consequences of this interplay and impact on the clinician's ability to diagnose, treat, prognosticate, and prevent the disability and distress of schizophrenia.

Estrogen replacement therapy for cognitive benefits: viable treatment or forgettable "senior moment"?

The perceived benefits of estrogen on cognitive function are one of the few remaining potential roles for estrogen replacement therapy. The justification for such a role has a strong biologic basis and is easily shown in animal models. Purported benefits for estrogen on cognitive function include neuroprotective, neurostimulating, and neurotrophic effects. The objective of this study was to review the literature and to evaluate the role of estrogen replacement therapy in improving cognition in Alzheimer disease, vascular dementia, premenopausal women, and postmenopausal women without dementia. Additionally, the authors separately looked at the neuroprotective effects of estrogen replacement therapy on the subsequent risk of dementia. The available data fail to show a therapeutic benefit of estrogen replacement therapy in Alzheimer disease. Surprisingly, limited data allow consideration of a possible role of estrogen in the management of vascular dementia. Additionally, younger females with low estrogen levels secondary to primary ovarian failure and Turner syndrome benefit from estrogen replacement therapy. Despite the limited role of estrogen replacement therapy in cognitive enhancement, neuroprotective properties are likely because several prospective studies indicate a reduced risk of Alzheimer disease. A critical window of opportunity seems to exist for this protective effect in Alzheimer disease because once established, the course of the disease is not affected by concomitant estrogen replacement therapy. The authors conclude that the use of estrogen replacement therapy is not substantiated for the treatment of patients with Alzheimer disease. Alternatively, because of the evidence for a possible neuroprotective effect, women at high risk for the development of Alzheimer disease may be appropriate candidates for estrogen replacement therapy. Such a decision should be made on a case-by-case basis, after careful consideration of the risks and benefits.

Effect of gonadectomy on subsequent development of age-related cognitive impairment in dogs

OBJECTIVE

To determine whether gonadectomy predisposes dogs to development of age-related behavioral changes linked to cognitive impairment.

DESIGN

Cohort study.

ANIMALS

29 sexually intact male dogs, 63 spayed female dogs, and 47 castrated male dogs 11 to 14 years old.

PROCEDURE

Information on possible impairments in 4 behavioral categories linked to cognitive impairment (orientation in the home and yard, social interactions, house training, and sleep-wake cycle) was obtained from owners of the dogs by use of a structured telephone interview format. A second interview was performed 12 to 18 months after the initial interview, and differences in responses were evaluated.

RESULTS

Sexually intact male dogs were significantly less likely than neutered dogs to progress from mild impairment (i.e., impairment in 1 category) to severe impairment (i.e., impairment in > or = 2 categories) during the time between the first and second interviews. This difference was not attributable to differences in ages of the dogs, duration of follow-up, or the owners' perceptions of the dogs' overall health.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that the presence of circulating testosterone in aging sexually intact male dogs may slow the progression of cognitive impairment, at least among dogs that already have signs of mild impairment. Estrogens would be expected to have a similar protective role in sexually intact female dogs; unfortunately, too few sexually intact female dogs were available for inclusion in the study to test this hypothesis. There may be a need to evaluate possible methods for counteracting the effects of loss of sex hormones in gonadectomized dogs.

Oestrogens and Alzheimer's disease

In the last decade, several reports suggest that oestrogen replacement therapy (ORT=ERT=estrogen replacement therapy) might prevent or delay Alzheimer's disease. Oestrogens influence and modulate brain structure and brain function. There are substantial arguments that the postmenopausal oestrogen loss might, together with other factors, accelerate the appearance of Alzheimer's disease. The evidence is suggestive, but not compelling, that ORT can reduce the relative risk to suffer from Alzheimer's disease. Furthermore, recent findings are consistent with the hypothesis that oestrogens might ameliorate the symptomatology in early stages of Alzheimer's disease. However, it has to be remembered that in most clinical trials the number of oestrogen users was quite small, and, usually, oestrogen use was not randomised. The aim of the present review is to discuss the data available today in view of their clinical relevance.

Neuroprotective effects of chronic estradiol benzoate treatment on hippocampal cell loss induced by status epilepticus in the female rat

Neuroprotective properties of estrogen are supported by extensive experimental evidence. In this study, the effects of estrogen were examined on the neurodegeneration secondary to status epilepticus induced by kainic acid in the rat. Chronic supplementation of ovariectomized rats with estradiol benzoate (20 microg/day) did not modify the expression of seizures monitored by electroencephalography, but significantly reduced cellular loss in the hippocampus. This neuroprotection was in particular observed in the dentate hilus and CA3 pyramidal layer when treatment with estradiol benzoate was started five days before status epilepticus induction. These findings suggest that estrogen can exert neuroprotective effects in a model of status epilepticus, in the absence of anti-epileptic properties.

Estrogen and basal forebrain cholinergic neurons: implications for brain aging and Alzheimer's disease-related cognitive decline

Recent studies suggest that estrogen replacement therapy can reduce the risk and severity of Alzheimer's disease (AD)-related dementia in postmenopausal women. Many different mechanisms by which estrogen therapy may help to reduce the risk and severity of AD-related pathophysiology have been proposed. Recent animal studies suggest that one way in which estrogen replacement may help to reduce cognitive deficits associated with aging and AD is by enhancing the functional status of cholinergic projections to the hippocampus and cortex. Here we review the evidence that estrogen is important in the maintenance of cholinergic neurons projecting to the hippocampus and cortex and that estrogen replacement can enhance the functional status of these neurons, as well as reduce cognitive deficits associated with muscarinic cholinergic impairment. Based on these studies, we conclude that, in animals, short-term treatment with physiological levels of estrogen, or estrogen and progesterone, has significant positive effects on cholinergic neurons in the medial septum and nucleus basalis magnocellularis and on their projections to the hippocampus and cortex. We hypothesize that similar effects in humans may help delay the decline in basal forebrain cholinergic function associated with aging and AD and thereby reduce the risk and severity of AD-related dementia in postmenopausal women.

Estrogen, cognition, and a woman's risk of Alzheimer's disease

Alzheimer's disease affects women more often than men, and women with this form of dementia show greater naming (semantic memory) deficits during the course of their illness. Gonadal steroids exert organizational and activational effects on central nervous system neurons and influence brain function in other important ways. Several estrogenic actions are potentially relevant to Alzheimer's disease, and it is hypothesized that one consequence of estrogen deprivation after the menopause is a higher risk of this dementing disorder. In healthy women without dementia, estrogen may enhance cognitive performance, especially in the domain of verbal memory, although the magnitude of such effects is small. Several small treatment trials of estrogen replacement in women with Alzheimer's disease, however, suggest that estrogen's effects on cognition could be larger in this population and may be most apparent on tasks of semantic memory. Analyses in voluntary cohorts associate postmenopausal estrogen replacement therapy with a lower risk of subsequent Alzheimer's disease. In 3 recent epidemiologic studies, information on postmenopausal estrogen use was collected prospectively; while inconclusive, findings raise the possibility that postmenopausal estrogen replacement reduces a woman's risk of subsequent dementia. New information from basic research and from large randomized treatment studies, cohort studies, and case-control studies is needed to resolve important unanswered clinical issues.

Role of oestrogen in the treatment and prevention of Alzheimer’s disease

Alzheimer's disease (AD), the most common primary dementing disorder, results in devastating clinical and socio-economic consequences, and is a leading cause of death among the elderly. Despite recent advances in the neurobiology of AD, identification of effective treatment strategies has remained frustratingly elusive. Administration of currently available cholinergic drugs improves symptoms in some patients with AD, but may be associated with efficacy-limiting adverse effects. Moreover, it is not yet known whether cholinergic drugs have the potential to alter the progression of AD pathology. In contrast, cumulative evidence from basic neuroscience and clinical research demonstrates that oestrogen has significant neuromodulatory and neuroprotective properties. Furthermore, preliminary evidence from clinical studies indicates that oestrogen replacement therapy can significantly enhance cognitive function in postmenopausal women with AD, and reduce the risk for developing the disease. However, long-term administration of oestrogen is associated with potentially serious adverse effects, including increased risk for developing malignancies of the uterus and the breast. Fortunately, tissue-specific analogues of oestrogen are in development that could specifically target the functions of the brain, and may be devoid of the cancer-inducing and feminising properties of the hormone. Availability of these analogues will make it feasible to treat AD with oestrogen in both women and men. However, findings of preliminary studies, although promising, need to be confirmed in larger, controlled clinical trials before the role of oestrogen in the treatment and prevention of AD can be firmly established.

Can estrogens prevent neurodegeneration?

Estrogen replacement therapy appears to have significant beneficial effects on cognition and mood in the elderly. In recent studies, its use has been associated with short term symptomatic cognitive improvement and with a decreased risk of (or a delay in) developing Alzheimer's disease (AD). Clinical reports are supported by substantial basic scientific evidence of the neuroprotective effects of estrogens. Their specific effects on dementia and cognitive impairment remain to be delineated. Ongoing randomised trials in AD will only provide information on the symptomatic effects of estrogen. Although basic research will progress, there is currently sufficient knowledge to promote active clinical research on the possible disease-modifying or neuroprotective effects of estrogens in the elderly.

Future therapeutic developments of estrogen use

The potential long-term benefits of estrogen replacement therapy (ERT) in the prevention of osteoporosis and heart disease have been reasonably well established. However, the favorable effects of ERT on cognitive function and prevention of senile dementia in old age now represents a revitalized area of clinical research. A growing body of experimental evidence has recently provided the neurobiologic basis to support the hypothesis that gonadal hormones such as estrogen have psychologic effects on human brain function and behavior. Studies in women who have undergone surgical menopause have demonstrated that the menopause is associated with subclinical cognitive and affective dysfunction, which is improved by ERT. In addition, a growing body of evidence suggests that estrogen may be an effective therapy for senile dementia in some elderly women. Recent epidemiologic studies have indicated that long-term postmenopausal ERT may prevent late-life cognitive dysfunction in older women. Several clinical trials employing oral estrogen therapy have also observed that some aged women with senile dementia have improved cognitive and affective function after estrogen therapy. Estrogen loss resulting in cognitive disorders, including menopausal cognitive dysfunction and senile dementia in late life, may act via several mechanisms. Estrogen may be an important growth factor for estrogen-responsive neurons. Estrogen therapy may also have substantial neurochemical effects, direct effects on the vasculature, and effects on the generation of free radicals, which may be toxic to neurons. At this time, several important clinical questions need to be answered regarding the role of ERT in the cognitive and affective dysfunctions associated with menopause and senile dementia. Should estrogen be used for menopausal women whose sole complaint is cognitive or affective dysfunction? Does long-term ERT prevent cognitive decline in late life if initiated at the time of menopause? Can ERT improve cognition and affective function in postmenopausal women with Alzheimer's disease, and does estrogen therapy prevent the progression of Alzheimer's disease in these patients? Finally, do the vascular effects of estrogen play a role in the treatment or prevention of both Alzheimer's disease and vascular dementia?

Estradiol enhances brain glucose uptake in ovariectomized rats

This study was designed to investigate the effects of 17 beta-estradiol benzoate (E2B) on brain glucose uptake and transport across the blood-brain barrier (BBB). Both a time- and dose-response evaluation of the effect of E2B on glucose uptake in the central nervous system (CNS) were conducted. E2B, in doses ranging from 1 to 100 micrograms/kg body weight, was injected subcutaneously at 2 to 24 h prior to evaluation. The 4-h time point and 10 micrograms/kg dose of E2B produced the most widespread increases in glucose uptake. Six regions responded to E2B with elevated glucose uptake by as much as 120% when compared to oil-treated controls. We then evaluated the effects of E2B on transport of glucose across the BBB. E2B significantly increased the extraction of labeled sugar across the BBB by 40% without affecting extraction of the internal standard. Collectively, these studies indicate that physiological levels of estradiol (E2) may play an important role in modulating cerebral glucose homeostasis.

Hypothalamic lesions increase levels of neuropeptide Y mRNA in the arcuate nucleus of mice

A recent study demonstrated that hypothalamic lesions induced by goldthioglucose (GTG) in mice produced an increase in neuronal immunoreactivity for neuropeptide Y (NPY) in the hypothalamic arcuate nucleus. Since NPY is a potent stimulator of feeding, this increase represented a potential explanation for the hyperphagia seen after GTG lesions. To examine whether or not this increase in NPY immunoreactivity was accompanied by an increase in the mRNA for NPY, in situ hybridization histochemistry for NPY mRNA in control and in lesioned mice was performed. A 47% increase in NPY mRNA levels in the arcuate nucleus was observed in lesioned mice compared with controls, suggesting that an increased expression of the gene for NPY contributes to elevations in hypothalamic NPY after lesioning. This elevation in NPY may, in turn, relate to mechanisms provoking hyperphagia.