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Hogervorst E. Effects of gonadal hormones on cognitive behaviour in elderly men and women. J Neuroendocrinol 2013; 25:1182-95. [PMID: 23895362 DOI: 10.1111/jne.12080] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 07/02/2013] [Accepted: 07/24/2013] [Indexed: 01/04/2023]
Abstract
Over the last four decades, animal and cell culture studies have shown that sex steroids can have protective effects on the ageing brain. Limited short-term positive effects (2-4 months) of oestrogen treatment were found in women without (as well as with) dementia. By contrast to these initial promising findings, several large treatment studies showed that longer-term oestrogen treatment, particularly when given in combination with progesterone, could exert negative effects on cognitive function in women aged over 65 years. Several observational studies of older women and men also suggest that longer exposure to higher endogenous oestrogen levels at an older age might confer risk for accelerated cognitive decline and dementia. However, health of participants may modify this association and, in women closer to the age at the onset of menopause, positive associations of oestrogens with cognition were also found. The 'healthy cell bias' theory suggests that oestrogens have protective effects in healthy neurones, although cells undergoing pathological change show acceleration in their demise when exposed to oestrogens. In older men, most studies reported higher bioavailable testosterone levels to be associated with better cognitive function. Other studies have reported optimal testosterone levels for better global cognitive function and a reduced risk of cognitive decline. Variation in health status over time and the use of (in)sensitive cognitive tests and hormone assays may explain why this was not always found. In older women, this association (of testosterone with cognition) is less clear. Small studies reported some benefits of testosterone treatment in combination with oestrogen on cognition, although these were of short duration. Several observational studies, on the other hand, found negative associations between high testosterone levels and worse cognitive function in older women. Age, health status, duration of treatment and sex may thus modify effects of longer-term elevated sex steroid levels on brain function.
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Affiliation(s)
- E Hogervorst
- Applied Cognitive Research Group, SSEHS, Loughborough University, Loughborough, Leicestershire, UK
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52
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Frick KM. Epigenetics, oestradiol and hippocampal memory consolidation. J Neuroendocrinol 2013; 25:1151-62. [PMID: 24028406 PMCID: PMC3943552 DOI: 10.1111/jne.12106] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 08/13/2013] [Accepted: 09/05/2013] [Indexed: 02/02/2023]
Abstract
Epigenetic alterations of histone proteins and DNA are essential for hippocampal synaptic plasticity and cognitive function, and contribute to the aetiology of psychiatric disorders and neurodegenerative diseases. Hippocampal memory formation depends on histone alterations and DNA methylation, and increasing evidence suggests that the regulation of these epigenetic processes by modulatory factors, such as environmental enrichment, stress and hormones, substantially influences memory function. Recent work from our laboratory suggests that the ability of the sex-steroid hormone 17β-oestradiol (E2 ) to enhance novel object recognition memory consolidation in young adult female mice is dependent on histone H3 acetylation and DNA methylation in the dorsal hippocampus. Our data also suggest that enzymes mediating DNA methylation and histone acetylation work in concert to regulate the effects of E2 on memory consolidation. These findings shed light on the epigenetic mechanisms that influence hormonal modulation of cognitive function, and may have important implications for understanding how hormones influence cognition in adulthood and ageing. The present review provides a brief overview of the literature on epigenetics and memory, describes in detail our findings demonstrating that epigenetic alterations regulate E2 -induced memory enhancement in female mice, and discusses future directions for research on the epigenetic regulation of E2 -induced memory enhancement.
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Affiliation(s)
- Karyn M. Frick
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53211
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53
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Maggio M, Colizzi E, Fisichella A, Valenti G, Ceresini G, Dall’Aglio E, Ruffini L, Lauretani F, Parrino L, Ceda GP. Stress hormones, sleep deprivation and cognition in older adults. Maturitas 2013; 76:22-44. [DOI: 10.1016/j.maturitas.2013.06.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 06/05/2013] [Indexed: 12/20/2022]
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Boss L, Kang DH, Marcus M, Bergstrom N. Endogenous Sex Hormones and Cognitive Function in Older Adults. West J Nurs Res 2013; 36:388-426. [DOI: 10.1177/0193945913500566] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Estrogen and testosterone may influence cognition in older adults, but the relationship between sex hormones and cognitive function is complex. The aim of this systematic review is to examine the role of sex hormones in cognitive function among older adults. A comprehensive, electronic review of literature was performed. Inclusion criteria were original quantitative research, written in English, used human subjects with a mean age of ≥60 years, and published from January 1997 through May 2012. Findings were mixed, although potential patterns were identified. Estradiol levels were potentially associated with benefits to episodic memory, semantic memory, verbal memory, and verbal learning in females only. The association between testosterone and cognitive function was mixed in both genders. Mixed findings may have been influenced by methodological differences and future studies should include research designs with ample rigor, sufficiently powered samples, consistent cognitive measurements, and clear descriptions of handling and storage of biological specimens.
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Affiliation(s)
- Lisa Boss
- University of Texas Health Science Center at Houston, USA
| | - Duck-Hee Kang
- University of Texas Health Science Center at Houston, USA
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55
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Samaras N, Samaras D, Lang PO, Forster A, Pichard C, Frangos E, Meyer P. A view of geriatrics through hormones. What is the relation between andropause and well-known geriatric syndromes? Maturitas 2013; 74:213-9. [DOI: 10.1016/j.maturitas.2012.11.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2012] [Revised: 10/24/2012] [Accepted: 11/21/2012] [Indexed: 11/29/2022]
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Luchsinger JA, Biggs ML, Kizer JR, Barzilay J, Fitzpatrick A, Newman A, Longstreth WT, Lopez O, Siscovick D, Kuller L. Adiposity and cognitive decline in the cardiovascular health study. Neuroepidemiology 2013; 40:274-81. [PMID: 23445925 PMCID: PMC4044822 DOI: 10.1159/000345136] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Accepted: 10/05/2012] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND Studies relating adiposity to cognition in the elderly show conflicting results, which may be explained by the choice of adiposity measures. Thus, we studied the longitudinal associations of different adiposity measures, fat mass by bioelectrical impedance analysis, body mass index (BMI) and waist circumference (WC), with cognitive performance in the Cardiovascular Health Study. METHODS Cognitive performance was assessed with the modified Mini-Mental State Examination, the Digit Symbol Substitution Test, and a composite of both. We used linear mixed models to estimate rates of change in cognitive function scores associated with adiposity measured at baseline. RESULTS The final sample was comprised of 2,681 women (57.9%) and 1,949 men (42.1%) aged 73 ± 5.2 and 73.9 ± 5.6 years, respectively. Adiposity was associated with slower cognitive decline in most analyses. Results were similar for fat mass, BMI and WC. Higher fat-free mass was also related to slower cognitive decline. Results were similar in analyses excluding persons with cancer, smokers, and persons with short follow-up, poor self-reported health, or persons with cardiovascular disease. CONCLUSIONS Higher adiposity and higher fat-free mass in the elderly was related to better cognitive performance. This finding was not explained by confounding by preexisting conditions.
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Affiliation(s)
- José A Luchsinger
- Departments of Medicine and Epidemiology, Columbia University Medical Center, Bronx, NY 10032, USA.
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Kulkarni J, Gavrilidis E, Worsley R, Van Rheenen T, Hayes E. The role of estrogen in the treatment of men with schizophrenia. Int J Endocrinol Metab 2013; 11:129-36. [PMID: 24348584 PMCID: PMC3860106 DOI: 10.5812/ijem.6615] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Revised: 08/20/2012] [Accepted: 09/28/2012] [Indexed: 12/23/2022] Open
Abstract
Schizophrenia is a debilitating and pervasive mental illness with devastating effects on many aspects of psychological, cognitive and social wellbeing. Epidemiological and life-cycle data point to significant differences in the incidence and course of schizophrenia between men and women, suggesting that estrogen plays a "protective" role . Adjunctive estrogen therapy has been shown to be effective in enhancing the treatment of schizophrenia in women. In men, consideration of estrogen therapy has been impacted by concerns of feminisation, however, clinical trials using estrogen to treat prostate cancer, bone density loss and even aggression in men with dementia or traumatic brain injury, show estrogen to be a safe and effective therapy. Findings do, however, suggest that further exploration of a therapeutic role for adjunctive estradiol treatment in men with schizophrenia is warranted. The development of the new estrogen compounds - Selective Estrogen Receptor Modulators (SERMs) which do not cause feminisation - opens up the possibility of using a different type of estrogen for a longer period of time at higher doses. Estrogen could therefore prove to be an important component in the treatment of psychotic symptoms in men with schizophrenia. This review explains the scientific rationale behind the estrogen hypothesis and how it can be clinically utilised to address concerns unique to the care of men with schizophrenia.
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Affiliation(s)
- Jayashri Kulkarni
- The Monash Alfred Psychiatry Research Centre, The Alfred and Monash University School of Psychology, Psychiatry and Psychological Medicine, Melbourne, Australia
- Corresponding author: Jayashri Kulkarni, Monash Alfred Psychiatry Research Centre, Level One, Old Baker Building, The Alfred Hospital, Commercial Rd, Melbourne 3004, Australia. Tel: +61-39076 6924, Fax:+ 61-39076 8545, E-mail:
| | - Emmy Gavrilidis
- The Monash Alfred Psychiatry Research Centre, The Alfred and Monash University School of Psychology, Psychiatry and Psychological Medicine, Melbourne, Australia
| | - Roisin Worsley
- The Monash Alfred Psychiatry Research Centre, The Alfred and Monash University School of Psychology, Psychiatry and Psychological Medicine, Melbourne, Australia
| | - Tamsyn Van Rheenen
- The Monash Alfred Psychiatry Research Centre, The Alfred and Monash University School of Psychology, Psychiatry and Psychological Medicine, Melbourne, Australia
| | - Emily Hayes
- The Monash Alfred Psychiatry Research Centre, The Alfred and Monash University School of Psychology, Psychiatry and Psychological Medicine, Melbourne, Australia
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Yao J, Irwin R, Chen S, Hamilton R, Cadenas E, Brinton RD. Ovarian hormone loss induces bioenergetic deficits and mitochondrial β-amyloid. Neurobiol Aging 2012; 33:1507-21. [PMID: 21514693 PMCID: PMC3181273 DOI: 10.1016/j.neurobiolaging.2011.03.001] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Revised: 02/15/2011] [Accepted: 03/01/2011] [Indexed: 01/08/2023]
Abstract
Previously, we demonstrated that reproductive senescence was associated with mitochondrial deficits comparable to those of female triple-transgenic Alzheimer's mice (3xTgAD). Herein, we investigated the impact of chronic ovarian hormone deprivation and 17β-estradiol (E2) replacement on mitochondrial function in nontransgenic (nonTg) and 3xTgAD female mouse brain. Depletion of ovarian hormones by ovariectomy (OVX) in nontransgenic mice significantly decreased brain bioenergetics, and induced mitochondrial dysfunction and oxidative stress. In 3xTgAD mice, OVX significantly exacerbated mitochondrial dysfunction and induced mitochondrial β-amyloid and β-amyloid (Aβ)-binding-alcohol-dehydrogenase (ABAD) expression. Treatment with E2 at OVX prevented OVX-induced mitochondrial deficits, sustained mitochondrial bioenergetic function, decreased oxidative stress, and prevented mitochondrial β-amyloid and ABAD accumulation. In vitro, E2 increased maximal mitochondrial respiration in neurons and basal and maximal respiration in glia. Collectively, these data demonstrate that ovarian hormone loss induced a mitochondrial phenotype comparable to a transgenic female model of Alzheimer's disease (AD), which was prevented by E2. These findings provide a plausible mechanism for increased risk of Alzheimer's disease in premenopausally oophorectomized women while also suggesting a therapeutic strategy for prevention.
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Affiliation(s)
- Jia Yao
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California 90033
| | - Ronald Irwin
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California 90033
| | - Shuhua Chen
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California 90033
| | - Ryan Hamilton
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California 90033
| | - Enrique Cadenas
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California 90033
| | - Roberta Diaz Brinton
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California 90033
- Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
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59
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Chace C, Pang D, Weng C, Temkin A, Lax S, Silverman W, Zigman W, Ferin M, Lee JH, Tycko B, Schupf N. Variants in CYP17 and CYP19 cytochrome P450 genes are associated with onset of Alzheimer's disease in women with down syndrome. J Alzheimers Dis 2012; 28:601-12. [PMID: 22057025 DOI: 10.3233/jad-2011-110860] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
CYP17 and CYP19 are involved in the peripheral synthesis of estrogens, and polymorphisms in CYP17 and CYP19 have been associated with increased risk of estrogen-related disorders. Women with Down syndrome (DS) have early onset and high risk for Alzheimer's disease (AD). We conducted a prospective community-based cohort study to examine the relationship between SNPs in CYP17 and CYP19 and cumulative incidence of AD, hormone levels and sex hormone binding globulin in women with DS. Two hundred and thirty-five women with DS, 31 to 67 years of age and nondemented at initial examination, were assessed for cognitive and functional abilities, behavioral/psychiatric conditions, and health status at 14-20 month intervals over five assessment cycles. We genotyped these individuals for single-nucleotide polymorphisms (SNPs) in CYP17 and CYP19. Four SNPs in CYP17 were associated with a two and one half-fold increased risk of AD, independent of APOE genotype. Four SNPs in CYP19 were associated with a two-fold increased risk of AD, although three were significant only in those without an APOE ε4 allele. Further, carrying high risk alleles in both CYP17 and CYP19 was associated with an almost four-fold increased risk of AD (OR = 3.8, 95% CI, 1.6-9.5) and elevated sex hormone binding globulin in postmenopausal women. The main effect of the CYP17 and CYP19 variants was to decrease the age at onset. These findings suggest that genes contributing to estrogen bioavailability influence risk of AD in women with DS.
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Affiliation(s)
- Constance Chace
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, NY, USA
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60
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Frick KM. Building a better hormone therapy? How understanding the rapid effects of sex steroid hormones could lead to new therapeutics for age-related memory decline. Behav Neurosci 2012; 126:29-53. [PMID: 22289043 DOI: 10.1037/a0026660] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A wealth of data collected in recent decades has demonstrated that ovarian sex-steroid hormones, particularly 17β-estradiol (E2), are important trophic factors that regulate the function of cognitive regions of the brain such as the hippocampus. The loss of hormone cycling at menopause is associated with cognitive decline and dementia in women, and the onset of memory decline in animal models. However, hormone therapy is not currently recommended to prevent or treat cognitive decline, in part because of its detrimental side effects. In this article, it is proposed that investigations of the rapid effects of E2 on hippocampal function be used to further the design of new drugs that mimic the beneficial effects of E2 on memory without the side effects of current therapies. A conceptual model is presented for elucidating the molecular and biochemical mechanisms through which sex-steroid hormones modulate memory, and a specific hypothesis is proposed to account for the rapid memory-enhancing effects of E2. Empirical support for this hypothesis is discussed as a means of stimulating the consideration of new directions for the development of hormone-based therapies to preserve memory function in menopausal women.
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Affiliation(s)
- Karyn M Frick
- Department of Psychology, University of Wisconsin-Milwaukee, 2441 East Hartford Avenue, Milwaukee, WI 53211, USA.
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61
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Metti AL, Cauley JA, Newman AB, Ayonayon HN, Barry LC, Kuller LM, Satterfield S, Simonsick EM, Yaffe K. Plasma beta amyloid level and depression in older adults. J Gerontol A Biol Sci Med Sci 2012; 68:74-9. [PMID: 22499763 DOI: 10.1093/gerona/gls093] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Older adults with depression have an increased risk of developing dementia. Low plasma beta-amyloid 42 (Aβ42) and Aβ42/Aβ40 have emerged as promising biomarkers of dementia. The association between depression and plasma Aβ is unclear. METHODS In this longitudinal study of 988 community-dwelling elders from the Health Aging and Body Composition study, depression was assessed with the Center for Epidemiologic Studies-Depression Scale 10-item version. We determined the association between Aβ42 and Aβ42/Aβ40 tertile and depression at baseline and over 9 years. We also stratified the models to determine if apolipoprotein E e4 allele status modified the associations. RESULTS Mean baseline age was 74.0 ± 3.0 years, 51 (5.2%) participants had depression, 545 (55.2%) were women, 531 (53.7%) were black, and 286 (30.7%) had one or more apolipoprotein E e4 allele. At baseline, there was no association between Aβ42/Aβ40 or Aβ42 and depression. Over 9 years, 220 (23.5%) participants developed depression. In adjusted Cox proportional hazards models, among those with one or more e4 allele, low Aβ42/Aβ40 was associated with an increased risk of developing depression over time (low 10.8% vs high 3.2%, hazard ratio = 2.38, 95% confidence interval: 1.15-4.92). Among those with no e4 allele, there was no association between Aβ42/Aβ40 and risk of depression over time (13.3% vs 17.5%, hazard ratio = 0.80, 95% confidence interval: 0.52-1.23; p value for interaction = .003). CONCLUSIONS The association between low plasma Aβ42/Aβ40 and increased risk of incident depression among those with one or more apolipoprotein E e4 allele implies a synergistic relationship similar to that found with dementia. Future work should investigate the interrelationships among plasma Aβ42/Aβ40, depression, and dementia.
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Affiliation(s)
- Andrea L Metti
- Center for Aging and Population Health, Department of Epidemiology, University of Pittsburgh, Pittsburgh, PA 15213, USA.
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Polymorphisms in HSD17B1: Early Onset and Increased Risk of Alzheimer's Disease in Women with Down Syndrome. Curr Gerontol Geriatr Res 2012; 2012:361218. [PMID: 22474448 PMCID: PMC3310186 DOI: 10.1155/2012/361218] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Accepted: 11/21/2011] [Indexed: 12/13/2022] Open
Abstract
Background/Aims. Genetic variants that affect estrogen activity may influence the risk of Alzheimer's disease (AD). In women with Down syndrome, we examined the relation of polymorphisms in hydroxysteroid-17beta-dehydrogenase (HSD17B1) to age at onset and risk of AD. HSD17B1 encodes the enzyme 17β-hydroxysteroid dehydrogenase (HSD1), which catalyzes the conversion of estrone to estradiol. Methods. Two hundred and thirty-eight women with DS, nondemented at baseline, 31-78 years of age, were followed at 14-18-month intervals for 4.5 years. Women were genotyped for 5 haplotype-tagging single-nucleotide polymorphisms (SNPs) in the HSD17B1 gene region, and their association with incident AD was examined. Results. Age at onset was earlier, and risk of AD was elevated from two- to threefold among women homozygous for the minor allele at 3 SNPs in intron 4 (rs676387), exon 6 (rs605059), and exon 4 in COASY (rs598126). Carriers of the haplotype TCC, based on the risk alleles for these three SNPs, had an almost twofold increased risk of developing AD (hazard ratio = 1.8, 95% CI, 1.1-3.1). Conclusion. These findings support experimental and clinical studies of the neuroprotective role of estrogen.
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63
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Henderson V, Popat R. Effects of endogenous and exogenous estrogen exposures in midlife and late-life women on episodic memory and executive functions. Neuroscience 2011; 191:129-38. [DOI: 10.1016/j.neuroscience.2011.05.059] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Revised: 04/27/2011] [Accepted: 05/24/2011] [Indexed: 02/06/2023]
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Testosterone levels and cognition in elderly men: a review. Maturitas 2011; 69:322-37. [PMID: 21696899 DOI: 10.1016/j.maturitas.2011.05.012] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Accepted: 05/22/2011] [Indexed: 11/24/2022]
Abstract
Average testosterone levels and many cognitive functions show a decline with age. There is evidence to suggest that this association is not just age related. Results from cell culture and animal studies provide convincing evidence that testosterone could have protective effects on brain function. Alzheimer's disease (AD) is characterised by brain pathology affecting cognitive function and AD prevalence increases with age. Testosterone levels are lower in AD cases compared to controls, and some studies have suggested that low free testosterone (FT) may precede AD onset. Men with AD may show accelerated endocrinological ageing, characterised by an earlier lowering of thyroid stimulating hormone, an earlier increase in sex hormone binding globulin (SHBG), a subsequent earlier decrease in FT and an earlier increase in gonadotropin levels in response to this. Positive associations have been found between testosterone levels and global cognition, memory, executive functions and spatial performance in observational studies. However, non-significant associations were also reported. It may be that an optimal level of testosterone exists at which some cognitive functions are improved. This may be modified with an older age, with a shifting of the optimal testosterone curve to maintain cognition to the left and a lower optimal level thus needed to be beneficial for the brain. Genetic factors, such as APOE and CAG polymorphisms may further interact with testosterone levels in their effects on cognition. The roles of SHBG, gonadotropins, thyroid hormones and estrogens in maintaining cognitive function and preventing dementia in men are also not completely understood and should be investigated further. Hypogonadal men do not seem to benefit from testosterone supplementation but small scale, short term intervention studies in eugonadal men with and without cognitive impairments have shown promising results. Larger randomised, controlled trials are needed to further investigate testosterone treatment in protecting against cognitive decline and/or dementia.
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65
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Lin J, Kroenke CH, Epel E, Kenna HA, Wolkowitz OM, Blackburn E, Rasgon NL. Greater endogenous estrogen exposure is associated with longer telomeres in postmenopausal women at risk for cognitive decline. Brain Res 2011; 1379:224-31. [PMID: 20965155 PMCID: PMC3057451 DOI: 10.1016/j.brainres.2010.10.033] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Revised: 10/07/2010] [Accepted: 10/11/2010] [Indexed: 01/01/2023]
Abstract
Longer duration of reproductive years of life and thus greater exposure to endogenous estrogen may be associated with a lower risk of age-related diseases in women. The present study examined the relationship between estimated endogenous estrogen exposure and telomere length (TL) and telomerase activity, two biomarkers of cellular aging, in a sample of postmenopausal women at risk for cognitive decline. Telomere length was measured using a quantitative PCR method and telomerase activity by TRAP (Telomere-Repeats Amplification Protocol) assay in peripheral blood mononuclear cells (PBMCs). Study subjects were 53 postmenopausal women (35 with natural and 18 with surgical menopause) receiving hormone therapy (HT) for at least one year or longer. Length of reproductive years of life, computed as the difference between age at menopause and age at menarche, was used as a proxy of duration of exposure to endogenous estrogen. Length of time on HT was the measure used for duration of exogenous estrogen exposure. We found that longer endogenous estrogen exposure was associated with greater TL (standardized β=0.06, Wald χ(2)=3.7, p=0.04) and with lower telomerase activity (standardized β=-0.09, Wald χ(2)=5.0, p=0.03). Length of reproductive years was also inversely associated with the combination of short TL and high telomerase (OR=0.78, 95% CI: 0.63, 0.97, p=0.02). Length of HT use was not associated with TL or telomerase activity in this study. The results suggest that the endogenous estrogens may be associated with deceleration of cellular aging. This is the first study to examine associations between endogenous estrogens, telomere length and telomerase activity.
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Affiliation(s)
- Jue Lin
- Department of Biochemistry and Biophysics, University of California, San Francisco
| | - Candyce H. Kroenke
- Center for Health and Community, Department of Psychiatry, University of California, San Francisco
| | - Elissa Epel
- Center for Health and Community, Department of Psychiatry, University of California, San Francisco
| | - Heather A. Kenna
- Stanford Center for Neuroscience in Women’s Health, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, United States
| | | | - Elizabeth Blackburn
- Department of Biochemistry and Biophysics, University of California, San Francisco
| | - Natalie L. Rasgon
- Stanford Center for Neuroscience in Women’s Health, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, United States
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Zimmerman ME, Lipton RB, Santoro N, McConnell DS, Derby CA, Katz MJ, Baigi K, Saunders-Pullman R. Endogenous estradiol is associated with verbal memory in nondemented older men. Brain Cogn 2011; 76:158-65. [PMID: 21354686 DOI: 10.1016/j.bandc.2011.01.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Revised: 11/18/2010] [Accepted: 01/31/2011] [Indexed: 12/17/2022]
Abstract
This study examined the relationship between endogenous hormones and cognitive function in nondemented, ethnically-diverse community-dwelling older men enrolled in the Einstein Aging Study (EAS). All eligible participants (185 men, mean age=81 years) received neuropsychological assessment (Free and Cued Selective Reminding Test (FCSRT), Logical Memory (LM), Trail Making Test B (TMTB), block design (BD)) and provided blood samples for hormonal assays (total estradiol, total testosterone, calculated free testosterone index). Linear regression analysis adjusted for age, education, body mass index, and cardiovascular comorbidities indicated that men with high levels of total estradiol demonstrated better FCSRT verbal memory performance (β=0.17, p<0.02) compared to men with lower levels of total estradiol. The results remained unchanged when the model was further adjusted for ethnicity. We did not detect an association between testosterone and cognitive performance. These findings indicate that high levels of total estradiol in older men are associated with better performance on a cue-based, controlled learning test of verbal memory that is a sensitive predictor of dementia.
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Affiliation(s)
- Molly E Zimmerman
- Albert Einstein College of Medicine, Department of Neurology, Bronx, NY 10461, USA.
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67
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Yaffe K, Weston A, Graff-Radford NR, Satterfield S, Simonsick EM, Younkin SG, Younkin LH, Kuller L, Ayonayon HN, Ding J, Harris TB. Association of plasma beta-amyloid level and cognitive reserve with subsequent cognitive decline. JAMA 2011; 305:261-6. [PMID: 21245181 PMCID: PMC3108075 DOI: 10.1001/jama.2010.1995] [Citation(s) in RCA: 161] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
CONTEXT Lower plasma β-amyloid 42 and 42/40 levels have been associated with incident dementia, but results are conflicting and few have investigated cognitive decline among elders without dementia. OBJECTIVE To determine if plasma β-amyloid is associated with cognitive decline and if this association is modified by measures of cognitive reserve. DESIGN, SETTING, AND PARTICIPANTS We studied 997 black and white community-dwelling older adults from Memphis, Tennessee, and Pittsburgh, Pennsylvania, who were enrolled in the Health ABC Study, a prospective observational study begun in 1997-1998 with 10-year follow-up in 2006-2007. Participant mean age was 74.0 (SD, 3.0) years; 55.2% (n = 550) were female; and 54.0% (n = 538) were black. MAIN OUTCOME MEASURES Association of near-baseline plasma β-amyloid levels (42 and 42/40 measured in 2010) and repeatedly measured Modified Mini-Mental State Examination (3MS) results. RESULTS Low β-amyloid 42/40 level was associated with greater 9-year 3MS cognitive decline (lowest β-amyloid tertile: mean change in 3MS score, -6.59 [95% confidence interval [CI], -5.21 to -7.67] points; middle tertile: -6.16 [95% CI, -4.92 to -7.32] points; and highest tertile: -3.60 [95% CI, -2.27 to -4.73] points; P < .001). Results were similar after multivariate adjustment for age, race, education, diabetes, smoking, and apolipoprotein E [APOE ] e4 status and after excluding the 72 participants with incident dementia. Measures of cognitive reserve modified this association whereby among those with high reserve (at least a high school diploma, higher than sixth-grade literacy, or no APOE e4 allele), β-amyloid 42/40 was less associated with multivariate adjusted 9-year decline. For example, among participants with less than a high school diploma, the 3MS score decline was -8.94 (95% CI, -6.94 to -10.94) for the lowest tertile compared with -4.45 (95% CI, -2.31 to -6.59) for the highest tertile, but for those with at least a high school diploma, 3MS score decline was -4.60 (95% CI,-3.07 to -6.13) for the lowest tertile and -2.88 (95% CI,-1.41 to -4.35) for the highest tertile (P = .004 for interaction). Interactions were also observed for literacy (P = .005) and for APOE e4 allele (P = .02). CONCLUSION Lower plasma β-amyloid 42/40 is associated with greater cognitive decline among elderly persons without dementia over 9 years, and this association is stronger among those with low measures of cognitive reserve.
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Affiliation(s)
- Kristine Yaffe
- Department of Psychiatry, University of California, San Francisco, and San Francisco Veterans Affairs Medical Center, San Francisco, CA 94121, USA.
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Boulware MI, Kent BA, Frick KM. The impact of age-related ovarian hormone loss on cognitive and neural function. Curr Top Behav Neurosci 2011; 10:165-84. [PMID: 21533680 DOI: 10.1007/7854_2011_122] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
On average, women now live one-third of their lives after menopause. Because menopause has been associated with an elevated risk of dementia, an increasing body of research has studied the effects of reproductive senescence on cognitive function. Compelling evidence from humans, nonhuman primates, and rodents suggests that ovarian sex-steroid hormones can have rapid and profound effects on memory, attention, and executive function, and on regions of the brain that mediate these processes, such as the hippocampus and prefrontal cortex. This chapter will provide an overview of studies in humans, nonhuman primates, and rodents that examine the effects of ovarian hormone loss and hormone replacement on cognitive functions mediated by the hippocampus and prefrontal cortex. For humans and each animal model, we outline the effects of aging on reproductive function, describe how ovarian hormones (primarily estrogens) modulate hippocampal and prefrontal physiology, and discuss the effects of both reproductive aging and hormone treatment on cognitive function. Although this review will show that much has been learned about the effects of reproductive senescence on cognition, many critical questions remain for future investigation.
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Affiliation(s)
- Marissa I Boulware
- Department of Psychology, University of Wisconsin-Milwaukee, 2441 E. Hartford Ave, Milwaukee, WI 53211, USA
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Abstract
Research increasingly suggests that changes in estrogen levels during aging may increase the risk of Alzheimer's disease, the most common type of dementia. This update reviews the newest information about estrogen and cognitive aging, including information regarding the role of bioavailable estrogen in older women and men, use of selective estrogen receptor modulators to improve cognition, and studies of genetic risk factors to elucidate the effects of endogenous estrogen on aging and cognition. Future trials are needed to determine whether alternate timing, dosage, formulation, or method of administration of hormone replacement can reduce the risk of dementia.
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Affiliation(s)
- Sarah C Janicki
- G. H. Sergievsky Center, Columbia University Medical Center, 622 West 168th Street, PH-19, New York, NY 10019, USA.
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Myers JS, Sousa VD, Donovan HS. Predictors of Self-Reported Memory Problems in Patients With Ovarian Cancer Who Have Received Chemotherapy. Oncol Nurs Forum 2010; 37:596-603. [DOI: 10.1188/10.onf.596-603] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Yaffe K, Lindquist K, Vittinghoff E, Barnes D, Simonsick EM, Newman A, Satterfield S, Rosano C, Rubin SM, Ayonayon HN, Harris T. The effect of maintaining cognition on risk of disability and death. J Am Geriatr Soc 2010; 58:889-94. [PMID: 20406308 DOI: 10.1111/j.1532-5415.2010.02818.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To determine whether long-term maintenance of cognition is associated with health advantages such as lower mortality or incident disability in older adults. DESIGN Longitudinal cohort study. SETTING Community clinics at two sites. PARTICIPANTS Two thousand seven hundred thirty-three adults with a mean age of 74 at baseline and 80 at follow-up. MEASUREMENTS Cognitive function was assessed using the Modified Mini-Mental State Examination (3MS), a test of global cognition, at least two times. Three cognitive groups were defined based on 4-year participant-specific slopes (maintainers, slopes of >or=0; minor decliners, slopes <0 but no more than 1 standard deviation (SD) below the mean; major decliners, slopes >1 SD below the mean). Whether the cognitive groups differed in mortality and incident disability during the subsequent 3 years was determined. RESULTS Nine hundred eighty-four (36%) participants were maintainers, 1,314 (48%) were minor decliners, and 435 (16%) were major decliners. Maintainers had lower mortality (7% vs 14%, hazard ratio (HR)=0.48, 95% confidence interval (CI)=0.36-0.63) and incident disability (22% vs 29%, HR=0.74, 95% CI=0.62-0.89) than minor decliners. After adjustment for age, race, sex, education, apolipoprotein E epsilon4, depression, body mass index, stroke, hypertension, and diabetes mellitus, these differences remained. As expected, major decliners had greater mortality (20%) and incident disability (40%) than minor decliners. CONCLUSION A substantial proportion of older adults maintain cognitive function in their eighth and ninth decades of life. These older adults demonstrate lower risk of death and functional decline than those with minor cognitive decline, supporting the concept of "successful" cognitive aging.
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Affiliation(s)
- Kristine Yaffe
- Department of Psychiatry, University of California at San Francisco, San Francisco, California 94121, USA.
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LeBlanc ES, Wang PY, Janowsky JS, Neiss MB, Fink HA, Yaffe K, Marshall LM, Lapidus JA, Stefanick ML, Orwoll ES. Association between sex steroids and cognition in elderly men. Clin Endocrinol (Oxf) 2010; 72:393-403. [PMID: 19744108 PMCID: PMC2852485 DOI: 10.1111/j.1365-2265.2009.03692.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To examine the association of cognitive function with sex steroid and sex hormone binding globulin (SHBG) levels among elderly men. DESIGN Prospective cohort study, The Osteoporotic Fractures in Men Study (MrOS), consisting of 5995 US community dwelling men of 65 years or older. PATIENTS One thousand six hundred and two men were chosen randomly from MrOS cohort for sex steroid level measurements by Mass Spectrometry (MS) at baseline. Two thousand six hundred and twenty-three MrOS participants with sex steroids measured using RIA were also examined. MEASUREMENTS Baseline and follow-up (4.5 years later) performance on two cognitive tests: Trails B (executive function and motor speed) and 3MS (global cognitive function). Baseline total testosterone and oestradiol were measured by MS. Free testosterone (free-T) and free oestradiol (free-E) were calculated. SHBG was measured by radioimmunoassay. Data were analysed using linear regression. RESULTS Baseline free-T and free-E levels were not associated with cognitive performance or change in cognition, following adjustment for age, education, race, health status and alcohol use. Baseline SHBG levels were inversely associated with follow-up trails B (P = 0.03) and 3MS performance (P = 0.02). Higher SHBG was associated with an increased risk of cognitive decline. Total sex steroid levels were not associated with cognitive performance. CONCLUSIONS Despite large numbers of participants and rigorous sex steroid measurements, we did not observe an association between cognition and either testosterone or oestradiol levels. We conclude that endogenous sex steroids in the normal range are not related to executive function or global cognitive function in elderly men. High SHBG deserves further examination as a risk factor for cognitive decline.
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Affiliation(s)
- Erin S LeBlanc
- Division of Endocrinology, Oregon Health & Science University, Portland, OR 97239, USA.
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Alibhai S, Mahmoud S, Hussain F, Naglie G, Tannock I, Tomlinson G, Fleshner N, Krahn M, Warde P, Klotz L, Breunis H, Leach M, Canning SD. Levels of sex hormones have limited effect on cognition in older men with or without prostate cancer. Crit Rev Oncol Hematol 2010; 73:167-75. [DOI: 10.1016/j.critrevonc.2009.03.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Revised: 02/23/2009] [Accepted: 03/04/2009] [Indexed: 11/30/2022] Open
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Hogervorst E, Matthews FE, Brayne C. Are optimal levels of testosterone associated with better cognitive function in healthy older women and men? Biochim Biophys Acta Gen Subj 2010; 1800:1145-52. [PMID: 20060437 DOI: 10.1016/j.bbagen.2009.12.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Revised: 12/04/2009] [Accepted: 12/31/2009] [Indexed: 12/01/2022]
Abstract
BACKGROUND Sex steroids can positively affect the brain and from this it would follow that high levels of sex steroids could be associated with better cognitive function in older men and women. METHODS This Healthy Ageing Study sample comprised of 521 older participants (51% women) without dementia at baseline, with an age range from 64 to 94 years. Testosterone and sex hormone binding globulin were measured using the automated Immulite 2000 and analyzed in association with baseline memory, global cognitive function and decline (assessed using the Mini-Mental Status Examination or MMSE) and controlling for potential confounds such as age, education, vascular disease, smoking, diabetes, thyroid function, and body mass index. RESULTS In healthy older men and women, optimal levels of testosterone were associated with better MMSE scores at baseline. Follow-up analyses indicated that in men, low testosterone levels (OR=.94, 95% CI=.88 to 1.00) were a risk factor for a sharp cognitive decline after 2 years, perhaps indicative of dementia. Associations were independent of covariates and baseline MMSE. Conversely, women at risk for a sharp drop in cognitive function showed some evidence for higher calculated free testosterone levels at baseline. CONCLUSIONS Results replicate earlier cross-sectional findings that high levels of sex steroids are not associated with better cognitive function in older people. In men, age accelerated endocrinological change could be associated with dementia pathology. GENERAL SIGNIFICANCE These data do not support increasing testosterone levels to prevent cognitive decline in men and women over 65 years of age.
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Affiliation(s)
- Eef Hogervorst
- Department of Human Sciences, Brockington Building, Loughborough University, Loughborough, UK.
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Oncology Nurse’s Perspective. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010. [DOI: 10.1007/978-1-4419-6306-2_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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DonCarlos LL, Azcoitia I, Garcia-Segura LM. Neuroprotective actions of selective estrogen receptor modulators. Psychoneuroendocrinology 2009; 34 Suppl 1:S113-22. [PMID: 19447561 PMCID: PMC2794899 DOI: 10.1016/j.psyneuen.2009.04.012] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Revised: 04/20/2009] [Accepted: 04/20/2009] [Indexed: 12/13/2022]
Abstract
Decreasing levels of sex hormones with aging may have a negative impact on brain function, since this decrease is associated with the progression of neurodegenerative disorders, increased depressive symptoms and other psychological disturbances. Extensive evidence from animal studies indicates that sex steroids, in particular estradiol, are neuroprotective. However, the potential benefits of estradiol therapy for the brain are counterbalanced by negative, life-threatening risks in the periphery. A potential therapeutic alternative to promote neuroprotection is the use of selective estrogen receptor modulators (SERMs), which may be designed to act with tissue selectivity as estrogen receptor agonists in the brain and not in other organs. Currently available SERMs act not only with tissue selectivity, but also with cellular selectivity within the brain and differentially modulate the activation of microglia, astroglia and neurons. Finally, SERMs may promote the interaction of estrogen receptors with the neuroprotective signaling of growth factors, such as the phosphatidylinositol 3-kinase/glycogen synthase kinase 3 pathway.
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Affiliation(s)
- Lydia L. DonCarlos
- Department of Cell Biology, Neurobiology and Anatomy, Stritch School of Medicine, Loyola University Chicago, 2160 South First Avenue, Maywood, Illinois 60153, USA. Tel: +1-7082164975; Fax: +1-7082163913; e-mail:
| | - Iñigo Azcoitia
- Departamento de Biología Celular, Facultad de Biología, Universidad Complutense, E-28040 Madrid, Spain. Tel: +34-913944861, Fax: +34-913944981 e-mail:
| | - Luis M. Garcia-Segura
- Instituto Cajal, CSIC, E-28002 Madrid, Spain. Tel:+34-915854729; Fax: +34-915854754; e-mail:
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Abstract
OBJECTIVE To review the relation in midlife and beyond between estrogen exposures and episodic memory in women. BACKGROUND Episodic memory performance declines with usual aging, and impairments in episodic memory often portend the development of Alzheimer disease. In the laboratory, estradiol influences hippocampal function and animal learning. However, it is controversial whether estrogens affect memory after a woman's reproductive years. METHOD Focused literature review, including a summary of a systematic search of clinical trials of estrogens in which outcomes included an objective measure of episodic memory. RESULTS The natural menopause transition is not associated with the objective changes in episodic memory. Strong clinical trial evidence indicates that initiating estrogen-containing hormone therapy after the age of about 60 years does not benefit episodic memory. Clinical trial findings in middle-aged women before the age of 60 years are limited by smaller sample sizes and shorter treatment durations, but these also do not indicate substantial memory effects. Limited short-term evidence, however, suggests that estrogens may improve verbal memory after surgical menopause. Although hormone therapy initiation in old age increases dementia risk, observational studies raise the question of an early critical window during which midlife estrogen therapy reduces late-life Alzheimer disease. However, almost no data address whether midlife estrogen therapy affects episodic memory in old age. CONCLUSIONS Episodic memory is not substantially impacted by the natural menopause transition or improved by the use of estrogen-containing hormone therapy after the age of 60 years. Further research is needed to determine whether outcomes differ after surgical menopause or whether episodic memory later in life is modified by midlife estrogenic exposures.
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Affiliation(s)
- Victor W Henderson
- Departments of Health Research and Policy (Epidemiology), and of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305-5405, USA.
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Abstract
BACKGROUND Changing world demographic patterns, such as the increasing number of older people and the growing prevalence of cognitive impairment, present serious obstacles to preserving the quality of life and productivity of individuals. The severity of dementia varies from subclinical, mild cognitive impairment to neurodegenerative diseases such as Alzheimer's. In normally ageing men, these age-related cognitive declines are accompanied by gradual but marked decreases in androgen levels and changes in other hormone profiles. While developmental effects of sex hormones on cognition in the pre- and early postnatal period have been demonstrated, their activational effects in later life are still a focus of contemporary research. Although there is a plethora of published research on the topic, results have been inconsistent with different studies reporting positive, negative or no effects of sex hormones on various aspects of mental agility. METHODS This review summarizes the evidence supporting the biological plausibility of the activational effects of sex hormones upon cognition and describes the mechanisms of their actions. It offers a comprehensive summary of the studies of the effects of sex hormones on fluid intelligence in men utilizing elements from the Cochrane Collaboration Guidelines for Reviews. The results of both observational (cross-sectional and longitudinal) and interventional studies published to date are collated in table form and further discussed in the text. Factors contributing to the difficulties in understanding the effects of sex hormones on cognition are also examined. CONCLUSIONS Although there is convincing evidence that steroid sex hormones play an organizational role in brain development in men, the evidence for activational effects of sex hormones affecting cognition in healthy men throughout adult life remains inconsistent. To address this issue, a new multifactorial approach is proposed which takes into account the status of other elements of the sex hormones axis including receptors, enzymes and other hormones.
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Affiliation(s)
- A Ulubaev
- Department of Endocrinology, Manchester Royal Infirmary, The University of Manchester, Manchester, UK.
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Mitochondrial haplogroup H and Alzheimer's disease—Is there a connection? Neurobiol Aging 2009; 30:1749-55. [DOI: 10.1016/j.neurobiolaging.2008.01.004] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2007] [Revised: 12/05/2007] [Accepted: 01/05/2008] [Indexed: 11/20/2022]
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Tierney MC, Oh P, Moineddin R, Greenblatt EM, Snow WG, Fisher RH, Iazzetta J, Hyslop PSG, MacLusky NJ. A randomized double-blind trial of the effects of hormone therapy on delayed verbal recall in older women. Psychoneuroendocrinology 2009; 34:1065-74. [PMID: 19297102 DOI: 10.1016/j.psyneuen.2009.02.009] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2008] [Revised: 02/08/2009] [Accepted: 02/12/2009] [Indexed: 11/27/2022]
Abstract
We examined whether estradiol and norethindrone hormone therapy (HT) prevented decline in delayed verbal recall in older women with normal to mildly impaired memory functioning. This was a 2-year, randomized, double-blind, placebo-controlled trial of 142 women aged 61-87, randomly assigned to receive 1 mg 17-beta estradiol daily and 0.35 mg norethindrone 3 days/week or daily placebo for 2 years. The primary outcome was short-delay verbal recall of the California Verbal Learning Test (CVLT). To look for differences in response to HT by baseline short-delay recall, we examined the primary outcome in participants grouped according to whether their baseline scores were below average for the age group or greater than or equal to this score and according to whether they met criteria for Mild Cognitive Impairment (MCI) or not. 133 women completed 1 year of the trial and 128 completed 2 years. Prespecified covariates in all repeated measures analyses of covariance (RANCOVA) included age, education, APOE epsilon4, and prior HT use. RANCOVA showed no overall significant treatment effects at year 1 or year 2. After testing for an interaction, which was significant (p=0.02), we found that women in the HT group who scored at or above the average showed significantly less decline than the placebo group in short-delay verbal recall after 1 year, p=0.007 and 2 years, p=0.01. No treatment effects were found in women below the average in either year. When grouped according to whether the participant met criteria for MCI, the interaction between treatment group and MCI subgroup was not significant. These results suggest that benefits of estrogen exposure may be limited to those with average to above average scores on the delayed verbal recall. HT dose and formulation may have contributed to these beneficial outcomes. Replication is warranted before recommendations can be made in the clinical setting.
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Affiliation(s)
- Mary C Tierney
- Brain Sciences, Sunnybrook Health Sciences Centre, Department of Family and Community Medicine, University of Toronto, Toronto, Ontario, Canada.
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Muller M, van den Beld AW, Grobbee DE, de Jong FH, Lamberts SWJ. Sex hormones and cognitive decline in elderly men. Psychoneuroendocrinology 2009; 34:27-31. [PMID: 18845400 DOI: 10.1016/j.psyneuen.2008.08.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2007] [Revised: 05/08/2008] [Accepted: 08/11/2008] [Indexed: 10/21/2022]
Abstract
Decline of cognitive function with age may be due, in part, to hormonal changes and it has been hypothesized that higher levels of endogenous sex hormones preserve brain function. The aim of this prospective cohort study was to determine the relative contribution of endogenous sex hormones to cognitive decline in a population-based sample of 242 elderly men aged 73-91 at baseline. Endogenous sex hormone levels were measured at baseline and participants underwent a cognitive assessment at baseline and at follow-up after 4 years. Higher estradiol (total and bioavailable) and estrone levels were associated with an increased risk of cognitive decline in elderly men independent of age, cardiovascular risk factors, atherosclerosis, and APOE genotype. These findings do not support the hypotheses that higher levels of endogenous sex hormones preserve brain function.
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Affiliation(s)
- Majon Muller
- Department of Geriatrics, University Medical Center Utrecht, The Netherlands
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Rocca WA, Shuster LT, Grossardt BR, Maraganore DM, Gostout BS, Geda YE, Melton LJ. Long-term effects of bilateral oophorectomy on brain aging: unanswered questions from the Mayo Clinic Cohort Study of Oophorectomy and Aging. WOMEN'S HEALTH (LONDON, ENGLAND) 2009; 5:39-48. [PMID: 19102639 PMCID: PMC2716666 DOI: 10.2217/17455057.5.1.39] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In the Mayo Clinic Cohort Study of Oophorectomy and Aging, women who had both ovaries removed before reaching natural menopause experienced a long-term increased risk of parkinsonism, cognitive impairment or dementia, and depressive and anxiety symptoms. Here, we discuss five possible mechanistic interpretations of the observed associations; first, the associations may be non-causal because they result from the confounding effect of genetic variants or of other risk factors; second, the associations may be mediated by an abrupt reduction in levels of circulating estrogen; third, the associations may be mediated by an abrupt reduction in levels of circulating progesterone or testosterone; fourth, the associations may be mediated by an increased release of gonadotropins by the pituitary gland; and fifth, genetic variants may modify the hormonal effects of bilateral oophorectomy through simple or more complex interactions. Results from other studies are cited as evidence for or against each possible mechanism. These putative causal mechanisms are probably intertwined, and their clarification is a research priority.
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Affiliation(s)
- W A Rocca
- Authors names & affiliations: Walter A. Rocca, Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 284-3568, fax: (507) 284-1516, e-mail: ; Lynne T. Shuster, Department of Internal Medicine, Women’s Health Clinic, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 538-6830, fax: (507) 266-3988, e-mail: ; Brandon R. Grossardt, Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 284-5007, fax: (507) 284-9542, e-mail: ; Demetrius M. Maraganore, Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 284-3219, fax: (507) 284-3665, e-mail: ; Bobbie S. Gostout, Division of Gynecologic Surgery, Department of Obstetrics & Gynecology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 266-8701, fax: (507) 266-9300, e-mail: ; Yonas E. Geda, Department of Psychiatry & Psychology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 284-3789, fax: (507) 284-4158, e-mail: ; L. Joseph Melton III, Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, 200 First Street SW, Rochester, MN, USA. Telephone: (507) 284-5545, fax: (507) 284-1516, e-mail:
| | - L T Shuster
- Authors names & affiliations: Walter A. Rocca, Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 284-3568, fax: (507) 284-1516, e-mail: ; Lynne T. Shuster, Department of Internal Medicine, Women’s Health Clinic, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 538-6830, fax: (507) 266-3988, e-mail: ; Brandon R. Grossardt, Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 284-5007, fax: (507) 284-9542, e-mail: ; Demetrius M. Maraganore, Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 284-3219, fax: (507) 284-3665, e-mail: ; Bobbie S. Gostout, Division of Gynecologic Surgery, Department of Obstetrics & Gynecology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 266-8701, fax: (507) 266-9300, e-mail: ; Yonas E. Geda, Department of Psychiatry & Psychology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 284-3789, fax: (507) 284-4158, e-mail: ; L. Joseph Melton III, Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, 200 First Street SW, Rochester, MN, USA. Telephone: (507) 284-5545, fax: (507) 284-1516, e-mail:
| | - B R Grossardt
- Authors names & affiliations: Walter A. Rocca, Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 284-3568, fax: (507) 284-1516, e-mail: ; Lynne T. Shuster, Department of Internal Medicine, Women’s Health Clinic, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 538-6830, fax: (507) 266-3988, e-mail: ; Brandon R. Grossardt, Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 284-5007, fax: (507) 284-9542, e-mail: ; Demetrius M. Maraganore, Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 284-3219, fax: (507) 284-3665, e-mail: ; Bobbie S. Gostout, Division of Gynecologic Surgery, Department of Obstetrics & Gynecology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 266-8701, fax: (507) 266-9300, e-mail: ; Yonas E. Geda, Department of Psychiatry & Psychology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 284-3789, fax: (507) 284-4158, e-mail: ; L. Joseph Melton III, Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, 200 First Street SW, Rochester, MN, USA. Telephone: (507) 284-5545, fax: (507) 284-1516, e-mail:
| | - D M Maraganore
- Authors names & affiliations: Walter A. Rocca, Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 284-3568, fax: (507) 284-1516, e-mail: ; Lynne T. Shuster, Department of Internal Medicine, Women’s Health Clinic, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 538-6830, fax: (507) 266-3988, e-mail: ; Brandon R. Grossardt, Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 284-5007, fax: (507) 284-9542, e-mail: ; Demetrius M. Maraganore, Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 284-3219, fax: (507) 284-3665, e-mail: ; Bobbie S. Gostout, Division of Gynecologic Surgery, Department of Obstetrics & Gynecology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 266-8701, fax: (507) 266-9300, e-mail: ; Yonas E. Geda, Department of Psychiatry & Psychology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 284-3789, fax: (507) 284-4158, e-mail: ; L. Joseph Melton III, Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, 200 First Street SW, Rochester, MN, USA. Telephone: (507) 284-5545, fax: (507) 284-1516, e-mail:
| | - B S Gostout
- Authors names & affiliations: Walter A. Rocca, Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 284-3568, fax: (507) 284-1516, e-mail: ; Lynne T. Shuster, Department of Internal Medicine, Women’s Health Clinic, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 538-6830, fax: (507) 266-3988, e-mail: ; Brandon R. Grossardt, Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 284-5007, fax: (507) 284-9542, e-mail: ; Demetrius M. Maraganore, Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 284-3219, fax: (507) 284-3665, e-mail: ; Bobbie S. Gostout, Division of Gynecologic Surgery, Department of Obstetrics & Gynecology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 266-8701, fax: (507) 266-9300, e-mail: ; Yonas E. Geda, Department of Psychiatry & Psychology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 284-3789, fax: (507) 284-4158, e-mail: ; L. Joseph Melton III, Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, 200 First Street SW, Rochester, MN, USA. Telephone: (507) 284-5545, fax: (507) 284-1516, e-mail:
| | - Y E Geda
- Authors names & affiliations: Walter A. Rocca, Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 284-3568, fax: (507) 284-1516, e-mail: ; Lynne T. Shuster, Department of Internal Medicine, Women’s Health Clinic, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 538-6830, fax: (507) 266-3988, e-mail: ; Brandon R. Grossardt, Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 284-5007, fax: (507) 284-9542, e-mail: ; Demetrius M. Maraganore, Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 284-3219, fax: (507) 284-3665, e-mail: ; Bobbie S. Gostout, Division of Gynecologic Surgery, Department of Obstetrics & Gynecology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 266-8701, fax: (507) 266-9300, e-mail: ; Yonas E. Geda, Department of Psychiatry & Psychology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 284-3789, fax: (507) 284-4158, e-mail: ; L. Joseph Melton III, Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, 200 First Street SW, Rochester, MN, USA. Telephone: (507) 284-5545, fax: (507) 284-1516, e-mail:
| | - L J Melton
- Authors names & affiliations: Walter A. Rocca, Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 284-3568, fax: (507) 284-1516, e-mail: ; Lynne T. Shuster, Department of Internal Medicine, Women’s Health Clinic, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 538-6830, fax: (507) 266-3988, e-mail: ; Brandon R. Grossardt, Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 284-5007, fax: (507) 284-9542, e-mail: ; Demetrius M. Maraganore, Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 284-3219, fax: (507) 284-3665, e-mail: ; Bobbie S. Gostout, Division of Gynecologic Surgery, Department of Obstetrics & Gynecology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 266-8701, fax: (507) 266-9300, e-mail: ; Yonas E. Geda, Department of Psychiatry & Psychology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. Telephone: (507) 284-3789, fax: (507) 284-4158, e-mail: ; L. Joseph Melton III, Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, 200 First Street SW, Rochester, MN, USA. Telephone: (507) 284-5545, fax: (507) 284-1516, e-mail:
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Abstract
In this article, the literature examining the relationship between testosterone and various cognitive domains in elderly men is reviewed. The review focuses on the role of endogenous testosterone levels and the effects of androgen depletion and replacement. The cognitive domains most commonly linked to testosterone include memory and visuospatial function. Indeed, the literature suggests that in certain conditions (ie, hypogonadism, cognitive impairment) testosterone levels may be significantly associated with memory and visuospatial function, but not other cognitive functions. Studies with larger sample sizes and more sensitive cognitive measures are indicated, as questions remain about the potential role of testosterone as a cognitive enhancer.
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Chu LW, Tam S, Lee PWH, Wong RLC, Yik PY, Tsui W, Song Y, Cheung BMY, Morley JE, Lam KSL. Bioavailable testosterone is associated with a reduced risk of amnestic mild cognitive impairment in older men. Clin Endocrinol (Oxf) 2008; 68:589-98. [PMID: 17973937 DOI: 10.1111/j.1365-2265.2007.03094.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE We investigated the risk of amnestic mild cognitive impairment (aMCI) in relation to serum bioavailable (BT) and total testosterone (TT) levels in older men. DESIGN, SETTING AND SUBJECTS A cross-sectional study in an ambulatory setting, with older men aged 55-93 years with normal cognition, aMCI and Alzheimer's disease (AD). MEASUREMENTS Morning serum BT and TT levels were determined. AD was diagnosed by the Neurological and Communicative Disorders and Stroke/Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA) criteria for probable AD and aMCI by the Petersen criteria. RESULTS We recruited 203 Chinese older men (48 aMCI, 66 AD and 89 with normal cognition). Mean serum BT, but not TT, levels were significantly lower in the aMCI (mean BT +/- SEM 1.06 +/- 0.10 nmol/l) and AD (0.99 +/- 0.08 nmol/l) groups than in the normal controls (1.82 +/- 0.12 nmol/l) (P < 0.001, one-way anova) with no significant difference between the aMCI and AD groups. After adjustment for education, age and apolipoprotein E (apoE) genotype, logistic regression analyses showed that the serum BT level [adjusted odds ratio (OR) = 0.52, 95% confidence interval (CI) 0.32-0.85] was an independent protective factor for aMCI. For the combined outcome of aMCI and AD, the serum BT level was an independent protective factor but age and apoE epsilon4 were independent risk factors. There was no interaction between BT and age. CONCLUSIONS In older men, serum BT, but not TT, levels were associated with a lower risk of aMCI and AD.
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Affiliation(s)
- Leung-Wing Chu
- Division of Geriatric Medicine, Department of Medicine, Queen Mary Hospital, Faculty of Medicine, The University of Hong Kong, Hong Kong SAR.
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85
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Sherwin BB, Henry JF. Brain aging modulates the neuroprotective effects of estrogen on selective aspects of cognition in women: a critical review. Front Neuroendocrinol 2008; 29:88-113. [PMID: 17980408 DOI: 10.1016/j.yfrne.2007.08.002] [Citation(s) in RCA: 223] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2007] [Revised: 07/17/2007] [Accepted: 08/14/2007] [Indexed: 11/28/2022]
Abstract
Although there is now a substantial literature on the putative neuroprotective effects of estrogen on cognitive functioning in postmenopausal women, it is replete with inconsistencies. The critical period hypothesis, posited several years ago, attempts to account for the discrepancies in this literature by positing that estrogen treatment (ET) will protect aspects of cognition in older women only when treatment is initiated soon after the menopause. Indeed, evidence from basic neuroscience and from the animal and human literature reviewed herein provides compelling support for the critical period hypothesis. Although it is not known with certainty why estrogen does not protect cognition and may even cause harm when administered to women over the age of 65years, it is likely that the events that characterize brain aging, such as a reduction in brain volume and in neuronal size, alterations in neurotransmitter systems, and a decrease in dendritic spine numbers, form an unfavorable background that precludes a neuroprotective effects of exogenous estrogen on the brain. Other factors that have likely contributed to the discrepancies in the estrogen-cognition literature include differences in the estrogen compounds used, their route of administration, cyclic versus continuous regimens, and the concomitant use of progestins. This critical analysis attempts to define conditions under which ET may protect aspects of cognition in aging women while also considering the cost/benefit ratio for the treatment of women aged 50-59years. Suggestions for specific future research questions are also addressed.
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Affiliation(s)
- Barbara B Sherwin
- McGill University, Department of Psychology, 1205 Dr. Penfield Avenue, Montreal, Que., Canada.
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86
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Abstract
The Alzheimer's disease (AD) is multifactorial. How to explain this group of very heterogeneous factors? Many of them can be considered as biopsychosocial risk factors. In other words, the risk factors, in link with the physiological functioning and a physiopathology, are difficultly dissociable of contingencies of psychological and/or social nature. The vital lead could be the stress bound to these variables, be it biological or psychosocial. It remains to ask the question of the preventive efficiency of treatments to relieve the impact of the traumatizing events of life that entail a depressive state or a state of posttraumatic stress. The hippocamp has to be the object of a quite particular attention. AD is a disease of the adaptation. This integrative model combines three vulnerabilities: a genetic vulnerability which would be there to dictate the type of lesions, their localization and the age of occurence; a psychobiographic vulnerability corresponding to a personality with inadequate mechanisms of defence, precarious adaptability in front of the adversity, weak impact strength and biography built on events of life during childhood, then during the grown-up life of traumatic nature, with a psychosocial environment insufficiently auxiliary; a neuroendocrinologic vulnerability which would base on a deregulation of the corticotrope axis, acquired during its infantile maturation, hampered by too premature stress. It would lead to a bad biological adaptability in stress later, at the origin of the observable lesions in the insanities.
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Affiliation(s)
- Jean-Pierre Clément
- Pôle de psychiatrie du sujet âgé, centre hospitalier Esquirol, SHU, 15, rue du Dr-Marcland, 87025 Limoges cedex, France.
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DonCarlos LL, Azcoitia I, Garcia-Segura LM. In search of neuroprotective therapies based on the mechanisms of estrogens. Expert Rev Endocrinol Metab 2007; 2:387-397. [PMID: 30743812 DOI: 10.1586/17446651.2.3.387] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Although estradiol is a neuroprotective factor, estrogen therapy in older women increases the risk of adverse cognitive outcomes and poses additional peripheral risks, requiring careful use of estrogenic compounds as treatments for neurodegenerative conditions or neural injury. Potential alternatives to estrogen therapy to promote neuroprotection might include treatment with molecules that are able to interact with estrogen receptors, with alternative mechanisms of action, or with molecules that induce local estradiol synthesis in the brain, or a combination of all. However, before considering the broad clinical applications, more basic research is required to clarify the mechanisms of action and potential risks of some of these estrogen-based treatments.
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Affiliation(s)
- Lydia L DonCarlos
- a Professor, Loyola University Chicago, Department of Cell Biology, Neurobiology and Anatomy, Stritch School of Medicine, 2160 South First Avenue, Maywood, IL 60153, USA.
| | - Iñigo Azcoitia
- b Associate Professor, Universidad Complutense, Departamento de Biología Celular, Facultad de Biología, E-28040 Madrid, Spain.
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