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Huang W, Zeng J, Jia L, Zhu D, O’Brien J, Ritchie C, Shu N, Su L. Genetic risks of Alzheimer's by APOE and MAPT on cortical morphology in young healthy adults. Brain Commun 2023; 5:fcad234. [PMID: 37693814 PMCID: PMC10489122 DOI: 10.1093/braincomms/fcad234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 07/29/2023] [Accepted: 08/30/2023] [Indexed: 09/12/2023] Open
Abstract
Genetic risk factors such as APOE ε4 and MAPT (rs242557) A allele are associated with amyloid and tau pathways and grey matter changes at both early and established stages of Alzheimer's disease, but their effects on cortical morphology in young healthy adults remain unclear. A total of 144 participants aged from 18 to 24 underwent 3T MRI and genotyping for APOE and MAPT to investigate unique impacts of these genetic risk factors in a cohort without significant comorbid conditions such as metabolic and cardiovascular diseases. We segmented the cerebral cortex into 68 regions and calculated the cortical area, thickness, curvature and folding index for each region. Then, we trained machine learning models to classify APOE and MAPT genotypes using these morphological features. In addition, we applied a growing hierarchical self-organizing maps algorithm, which clustered the 68 regions into 4 subgroups representing different morphological patterns. Then, we performed general linear model analyses to estimate the interaction between APOE and MAPT on cortical patterns. We found that the classifiers using all cortical features could accurately classify individuals carrying genetic risks of dementia outperforming each individual feature alone. APOE ε4 carriers had a more convoluted and thinner cortex across the cerebral cortex. A similar pattern was found in MAPT A allele carriers only in the regions that are vulnerable for early tau pathology. With the clustering analysis, we found a synergetic effect between APOE ε4 and MAPT A allele, i.e. carriers of both risk factors showed the most deviation of cortical pattern from the typical pattern of that cluster. Genetic risk factors of dementia by APOE ε4 and MAPT (rs242557) A allele were associated with variations of cortical morphology, which can be observed in young healthy adults more than 30 years before Alzheimer's pathology is likely to occur and 50 years before dementia symptoms may begin.
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Affiliation(s)
- Weijie Huang
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing 100875, China
- Department of Neuroscience, Neuroscience Institute, Insigneo Institute for In Silico Medicine, University of Sheffield, Sheffield S10 2HQ, UK
- School of Systems Science, Beijing Normal University, Beijing 100875, China
| | - Jianmin Zeng
- Faculty of Psychology, Sino-Britain Centre for Cognition and Ageing Research, Southwest University, Chongqing 400715, China
| | - Lina Jia
- Beijing Anding Hospital, Capital Medical University, Beijing 100088, China
| | - Dajiang Zhu
- Department of Computer Science and Engineering, University of Texas at Arlington, Arlington, TX 76019, USA
| | - John O’Brien
- Department of Psychiatry, School of Clinical Medicine, University of Cambridge, Cambridge CB2 0SZ, UK
| | - Craig Ritchie
- Edinburgh Dementia Prevention and Centre for Clinical Brain Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh EH4 2XU, UK
- Scottish Brain Sciences, Edinburgh EH12 9DQ, UK
| | - Ni Shu
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing 100875, China
| | - Li Su
- Department of Neuroscience, Neuroscience Institute, Insigneo Institute for In Silico Medicine, University of Sheffield, Sheffield S10 2HQ, UK
- Department of Psychiatry, School of Clinical Medicine, University of Cambridge, Cambridge CB2 0SZ, UK
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Association between APOE e4 and white matter hyperintensity volume, but not total brain volume or white matter integrity. Brain Imaging Behav 2021; 14:1468-1476. [PMID: 30903549 PMCID: PMC7572345 DOI: 10.1007/s11682-019-00069-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Apolipoprotein (APOE) e4 genotype is an accepted risk factor for accelerated cognitive aging and dementia, though its neurostructural substrates are unclear. The deleterious effects of this genotype on brain structure may increase in magnitude into older age. This study aimed to investigate in UK Biobank the association between APOE e4 allele presence vs. absence and brain imaging variables that have been associated with worse cognitive abilities; and whether this association varies by cross-sectional age. We used brain magnetic resonance imaging (MRI) and genetic data from a general-population cohort: the UK Biobank (N = 8395 after exclusions). We adjusted for the covariates of age in years, sex, Townsend social deprivation scores, smoking history and cardiometabolic diseases. There was a statistically significant association between APOE e4 genotype and increased (i.e. worse) white matter (WM) hyperintensity volumes (standardised beta = 0.088, 95% confidence intervals = 0.036 to 0.139, P = 0.001), a marker of poorer cerebrovascular health. There were no associations with left or right hippocampal, total grey matter (GM) or WM volumes, or WM tract integrity indexed by fractional anisotropy (FA) and mean diffusivity (MD). There were no statistically significant interactions with age. Future research in UK Biobank utilising intermediate phenotypes and longitudinal imaging hold significant promise for this area, particularly pertaining to APOE e4’s potential link with cerebrovascular contributions to cognitive aging.
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de la Torre JC. Deciphering Alzheimer's Disease Pathogenic Pathway: Role of Chronic Brain Hypoperfusion on p-Tau and mTOR. J Alzheimers Dis 2021; 79:1381-1396. [PMID: 33459641 DOI: 10.3233/jad-201165] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
This review examines new biomolecular findings that lend support to the hemodynamic role played by chronic brain hypoperfusion (CBH) in driving a pathway to Alzheimer's disease (AD). CBH is a common clinical feature of AD and the current topic of intense investigation in AD models. CBH is also the basis for the vascular hypothesis of AD which we originally proposed in 1993. New biomolecular findings reveal the interplay of CBH in increasing tau phosphorylation (p-Tau) in the hippocampus and cortex of AD mice, damaging fast axonal transport, increasing signaling of mammalian target of rapamycin (mTOR), impairing learning-memory function, and promoting the formation of neurofibrillary tangles, a neuropathologic hallmark of AD. These pathologic elements have been singularly linked with neurodegeneration and AD but their abnormal, collective participation during brain aging have not been fully examined. The format for this review will provide a consolidated analysis of each pathologic phase contributing to cognitive decline and AD onset, summarized in nine chronological steps. These steps galvanize each factor's active participation and contribution in constructing a biomolecular pathway to AD onset generated by CBH.
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Affiliation(s)
- Jack C de la Torre
- Department of Psychology, University of Texas at Austin, Austin, TX, USA.,Department of Physiology, University of Valencia Faculty of Medicine, Valencia, Spain
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Rhea EM, Raber J, Banks WA. ApoE and cerebral insulin: Trafficking, receptors, and resistance. Neurobiol Dis 2020; 137:104755. [PMID: 31978603 PMCID: PMC7050417 DOI: 10.1016/j.nbd.2020.104755] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 01/13/2020] [Accepted: 01/20/2020] [Indexed: 12/16/2022] Open
Abstract
Central nervous system (CNS) insulin resistance is associated with Alzheimer's disease (AD). In addition, the apolipoprotein E4 (apoE4) isoform is a risk factor for AD. The connection between these two factors in relation to AD is being actively explored. We summarize this literature with a focus on the transport of insulin and apoE across the blood-brain barrier (BBB) and into the CNS, the impact of apoE and insulin on the BBB, and the interactions between apoE, insulin, and the insulin receptor once present in the CNS. We highlight how CNS insulin resistance is apparent in AD and potential ways to overcome this resistance by repurposing currently approved drugs, with apoE genotype taken into consideration as the treatment response following most interventions is apoE isoform-dependent. This review is part of a special issue focusing on apoE in AD and neurodegeneration.
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Affiliation(s)
- Elizabeth M Rhea
- Research and Development, Veterans Affairs Puget Sound Healthcare System, Seattle, WA 98108, United States of America; Department of Medicine, University of Washington, Seattle, WA 98195, United States of America.
| | - Jacob Raber
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, United States of America; Departments of Neurology and Radiation Medicine, Division of Neuroscience, ONPRC, Oregon Health & Science University, Portland, OR 97239, United States of America
| | - William A Banks
- Research and Development, Veterans Affairs Puget Sound Healthcare System, Seattle, WA 98108, United States of America; Department of Medicine, University of Washington, Seattle, WA 98195, United States of America
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Johnson LA, Torres ER, Weber Boutros S, Patel E, Akinyeke T, Alkayed NJ, Raber J. Apolipoprotein E4 mediates insulin resistance-associated cerebrovascular dysfunction and the post-prandial response. J Cereb Blood Flow Metab 2019; 39:770-781. [PMID: 29215310 PMCID: PMC6498752 DOI: 10.1177/0271678x17746186] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Metabolic dysfunction, commonly a result of diets high in saturated fats and sugar, is associated with impaired cognitive function and an increased risk of age-related cognitive decline (ACD) and Alzheimer's disease (AD). Compared to the E3 isoform of apolipoprotein (apoE), the E4 isoform is a major genetic risk factor for ACD, AD, and for developing cognitive impairments following various environmental challenges, including dietary challenges such as a high-fat diet (HFD). Both insulin resistance (IR) and E4 are associated with metabolic and vascular impairments. Deficits in cerebral metabolism and cerebrovascular function have been proposed as initiating events leading to these impairments. In the current study, we employed a model of human apoE targeted replacement mice and HFD-induced obesity to study the potential link between E4 and IR, at rest and following a postprandial challenge. HFD-induced IR was associated with impaired cognition, reduced cerebral blood volume and decreased glucose uptake. These effects were more profound in E4 than E3 mice. Furthermore, the cognitive, metabolic and cerebrovascular responses to an exogenous glucose load showed an apoE isoform-dependent response, with E4, but not E3 mice, acutely benefiting from a spike in blood glucose.
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Affiliation(s)
- Lance A Johnson
- 1 Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA.,2 Department of Physiology, University of Kentucky, Lexington, KY 40536 USA
| | - Eileen Ruth Torres
- 1 Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA
| | - Sydney Weber Boutros
- 1 Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA
| | - Esha Patel
- 1 Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA
| | - Tunde Akinyeke
- 1 Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA
| | - Nabil J Alkayed
- 3 Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA.,4 Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA
| | - Jacob Raber
- 1 Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA.,5 Department of Neurology and Radiation Medicine, Oregon Health & Science University, Portland, OR, USA
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Weissberger GH, Nation DA, Nguyen CP, Bondi MW, Han SD. Meta-analysis of cognitive ability differences by apolipoprotein e genotype in young humans. Neurosci Biobehav Rev 2018; 94:49-58. [PMID: 30125600 DOI: 10.1016/j.neubiorev.2018.08.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 05/21/2018] [Accepted: 08/16/2018] [Indexed: 12/14/2022]
Abstract
The apolipoprotein (APOE) ε4 allele has been proposed as an example of an antagonistic pleiotropy gene, conferring a beneficial effect on cognition in early life and a detrimental impact on cognition during later years. However, findings on the cognitive associations of the ε4 allele in younger persons are mixed. This PRISMA conforming study aimed to investigate APOE genotype (e4/non-e4) associations across seven cognitive domains (intelligence/achievement, attention/working memory, executive functioning, memory, language, processing speed and visuospatial abilities) in younger humans using a meta-analytic approach. Of 689 records reviewed, 29 studies (34 data-points) were selected for the quantitative synthesis. Participants' ages ranged from 2-40. Results showed that young ε4 carriers did not statistically differ from non-ε4 carriers across any cognitive domains. Overall, findings do not provide compelling support for an antagonistic pleiotropic effect of the ε4 allele across the lifespan.
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Affiliation(s)
- Gali H Weissberger
- Department of Family Medicine, USC Keck School of Medicine, 1000 S. Fremont Avenue, Unit 22, HSA Building A-6, 4thFloor, Room 6437A, Alhambra, CA, 91803, USA.
| | - Daniel A Nation
- Department of Psychology, USC Dornsife College of Letters, Arts, and Sciences, Los Angeles, 90089, CA, USA
| | - Caroline P Nguyen
- Department of Family Medicine, USC Keck School of Medicine, 1000 S. Fremont Avenue, Unit 22, HSA Building A-6, 4thFloor, Room 6437A, Alhambra, CA, 91803, USA
| | - Mark W Bondi
- Department of Psychiatry, University of California, San Diego, 9500 Gilman Drive #9116-B, La Jolla, CA, 92093, USA
| | - S Duke Han
- Department of Family Medicine, USC Keck School of Medicine, 1000 S. Fremont Avenue, Unit 22, HSA Building A-6, 4thFloor, Room 6437A, Alhambra, CA, 91803, USA; Department of Psychology, USC Dornsife College of Letters, Arts, and Sciences, Los Angeles, 90089, CA, USA; USC School of Gerontology, Los Angeles, CA, 90089, USA; Department of Neurology, USC Keck School of Medicine, Los Angeles, 90033, CA, USA
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Hu L, Xu Q, Li J, Wang F, Xu X, Sun Z, Ma X, Liu Y, Wang Q, Wang D. No differences in brain microstructure between young KIBRA-C carriers and non-carriers. Oncotarget 2018; 9:1200-1209. [PMID: 29416687 PMCID: PMC5787430 DOI: 10.18632/oncotarget.23348] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 12/04/2017] [Indexed: 11/25/2022] Open
Abstract
KIBRA rs17070145 polymorphism is associated with variations in memory function and the microstructure of related brain areas. Diffusion kurtosis imaging (DKI) as an extension of diffusion tensor imaging that can provide more information about changes in microstructure, based on the idea that water diffusion in biological tissues is heterogeneous due to structural hindrance and restriction. We used DKI to explore the relationship between KIBRA gene polymorphism and brain microstructure in young adults. We recruited 100 healthy young volunteers, including 53 TT carriers and 47 C allele carriers. No differences were detected between the TT homozygotes and C-allele carriers for any diffusion and kurtosis parameter. These results indicate KIBRA rs17070145 polymorphism likely has little or no effect on brain microstructure in young adults.
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Affiliation(s)
- Li Hu
- Department of Radiology, Qilu Hospital of Shandong University, Jinan 250012, China
| | - Qunxing Xu
- Medical Examination Center, Qilu Hospital of Shandong University, Jinan 250012, China
| | - Jizhen Li
- Mental Health Center of Shandong Province, Jinan 250012, China
| | - Feifei Wang
- Department of Radiology, Qilu Hospital of Shandong University, Jinan 250012, China
| | - Xinghua Xu
- Department of Radiology, Qilu Hospital of Shandong University, Jinan 250012, China
| | - Zhiyuan Sun
- Department of Radiology, Qilu Hospital of Shandong University, Jinan 250012, China
| | - Xiangxing Ma
- Department of Radiology, Qilu Hospital of Shandong University, Jinan 250012, China
| | - Yong Liu
- Brainnetome Center, National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China
| | - Qing Wang
- Department of Radiology, Qilu Hospital of Shandong University, Jinan 250012, China
| | - Dawei Wang
- Department of Radiology, Qilu Hospital of Shandong University, Jinan 250012, China
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A Dietary Treatment Improves Cerebral Blood Flow and Brain Connectivity in Aging apoE4 Mice. Neural Plast 2016; 2016:6846721. [PMID: 27034849 PMCID: PMC4806294 DOI: 10.1155/2016/6846721] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 02/22/2016] [Indexed: 11/17/2022] Open
Abstract
APOE ε4 (apoE4) polymorphism is the main genetic determinant of sporadic Alzheimer's disease (AD). A dietary approach (Fortasyn) including docosahexaenoic acid, eicosapentaenoic acid, uridine, choline, phospholipids, folic acid, vitamins B12, B6, C, and E, and selenium has been proposed for dietary management of AD. We hypothesize that the diet could inhibit AD-like pathologies in apoE4 mice, specifically cerebrovascular and connectivity impairment. Moreover, we evaluated the diet effect on cerebral blood flow (CBF), functional connectivity (FC), gray/white matter integrity, and postsynaptic density in aging apoE4 mice. At 10–12 months, apoE4 mice did not display prominent pathological differences compared to wild-type (WT) mice. However, 16–18-month-old apoE4 mice revealed reduced CBF and accelerated synaptic loss. The diet increased cortical CBF and amount of synapses and improved white matter integrity and FC in both aging apoE4 and WT mice. We demonstrated that protective mechanisms on vascular and synapse health are enhanced by Fortasyn, independent of apoE genotype. We further showed the efficacy of a multimodal translational approach, including advanced MR neuroimaging, to study dietary intervention on brain structure and function in aging.
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Modulation effect of the SORL1 gene on functional connectivity density in healthy young adults. Brain Struct Funct 2015; 221:4103-4110. [DOI: 10.1007/s00429-015-1149-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 11/17/2015] [Indexed: 12/12/2022]
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Ritchie K, Ritchie CW, Yaffe K, Skoog I, Scarmeas N. Is late-onset Alzheimer's disease really a disease of midlife? ALZHEIMER'S & DEMENTIA (NEW YORK, N. Y.) 2015; 1:122-130. [PMID: 29854932 PMCID: PMC5975058 DOI: 10.1016/j.trci.2015.06.004] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
INTRODUCTION Increasing evidence suggests that Alzheimer's disease (AD) may begin decades before evidence of dementia, indicating that it may be a disorder of midlife rather than old age. METHODS In the absence of long-term prospective studies from early adulthood specifically designed to address this question, a group of international experts examined evidence presently available from previous clinical and population studies to provide an evidence-based opinion as to whether such a change in conceptualization may be justified. RESULTS Although still lacking confirmation from dedicated prospective biomarker studies, there is already considerable evidence to suggest both risk factor exposure and brain changes may be already present in midlife. DISCUSSION Current evidence suggests (1) that a change in clinical approach notably involving promotion of cardiovascular health in persons with a family history of AD may considerably reduce disease risk and (2) that the development of biomarkers at this early stage will lead to the possibility of clinical trials at a much earlier stage.
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Affiliation(s)
- Karen Ritchie
- Institut National de la Santé et de la Recherche Médicale, U1061 Neuropsychiatry, Montpellier, France
- Faculty of Medicine, University of Montpellier, France
| | - Craig W. Ritchie
- Faculty of Medicine, Imperial College London, UK
- Department of Psychiatry, University of Edinburgh, UK
| | | | - Ingmar Skoog
- Centre for Health and Ageing (AgeCap), Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Sweden
| | - Nikolaos Scarmeas
- Department of Social Medicine, Psychiatry and Neurology, National and Kapodistrian University of Athens, Greece
- Taub Institute for Research in Alzheimer's Disease and the Aging Brain, the Gertrude H. Sergievsky Center, Department of Neurology, Columbia University, New York, NY, USA
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Apolipoprotein ε4 is associated with lower brain volume in cognitively normal Chinese but not white older adults. PLoS One 2015; 10:e0118338. [PMID: 25738563 PMCID: PMC4349764 DOI: 10.1371/journal.pone.0118338] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 01/14/2015] [Indexed: 12/12/2022] Open
Abstract
Studying ethnically diverse groups is important for furthering our understanding of biological mechanisms of disease that may vary across human populations. The ε4 allele of apolipoprotein E (APOE ε4) is a well-established risk factor for Alzheimer's disease (AD), and may confer anatomic and functional effects years before clinical signs of cognitive decline are observed. The allele frequency of APOE ε4 varies both across and within populations, and the size of the effect it confers for dementia risk may be affected by other factors. Our objective was to investigate the role APOE ε4 plays in moderating brain volume in cognitively normal Chinese older adults, compared to older white Americans. We hypothesized that carrying APOE ε4 would be associated with reduced brain volume and that the magnitude of this effect would be different between ethnic groups. We performed whole brain analysis of structural MRIs from Chinese living in America (n = 41) and Shanghai (n = 30) and compared them to white Americans (n = 71). We found a significant interaction effect of carrying APOE ε4 and being Chinese. The APOE ε4xChinese interaction was associated with lower volume in bilateral cuneus and left middle frontal gyrus (Puncorrected<0.001), with suggestive findings in right entorhinal cortex and left hippocampus (Puncorrected<0.01), all regions that are associated with neurodegeneration in AD. After correction for multiple testing, the left cuneus remained significantly associated with the interaction effect (PFWE = 0.05). Our study suggests there is a differential effect of APOE ε4 on brain volume in Chinese versus white cognitively normal elderly adults. This represents a novel finding that, if verified in larger studies, has implications for how biological, environmental and/or lifestyle factors may modify APOE ε4 effects on the brain in diverse populations.
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Abstract
It is well established that the cholesterol-transporter apolipoprotein ε (APOE) genotype is associated with the risk of developing neurodegenerative diseases. Recently, brain functional connectivity (FC) in apoE-ε4 carriers has been investigated by means of resting-state fMRI, showing a marked differentiation in several functional networks at different ages compared with carriers of other apoE isoforms. The causes of such hampered FC are not understood. We hypothesize that vascular function and synaptic repair processes, which are both impaired in carriers of ε4, are the major contributors to the loss of FC during aging. To test this hypothesis, we integrated several different MRI techniques with immunohistochemistry and investigated FC changes in relation with perfusion, diffusion, and synaptic density in apoE4 and apoE-knock-out (KO) mice at 12 (adult) and 18 months of age. Compared with wild-type mice, we detected FC deficits in both adult and old apoE4 and apoE-KO mice. In apoE4 mice, these changes occurred concomitant with increased mean diffusivity in the hippocampus, whereas perfusion deficits appear only later in life, together with reduced postsynaptic density levels. Instead, in apoE-KO mice FC deficits were mirrored by strongly reduced brain perfusion since adulthood. In conclusion, we provide new evidence for a relation between apoE and brain connectivity, possibly mediated by vascular risk factors and by the efficiency of APOE as synaptic modulator in the brain. Our results show that multimodal MR neuroimaging is an excellent tool to assess brain function and to investigate early neuropathology and aging effects in translational research.
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Dell'Acqua F, Khan W, Gottlieb N, Giampietro V, Ginestet C, Bouls D, Newhouse S, Dobson R, Banaschewski T, Barker GJ, Bokde ALW, Büchel C, Conrod P, Flor H, Frouin V, Garavan H, Gowland P, Heinz A, Lemaítre H, Nees F, Paus T, Pausova Z, Rietschel M, Smolka MN, Ströhle A, Gallinat J, Westman E, Schumann G, Lovestone S, Simmons A. Tract Based Spatial Statistic Reveals No Differences in White Matter Microstructural Organization between Carriers and Non-Carriers of the APOE ɛ4 and ɛ2 Alleles in Young Healthy Adolescents. J Alzheimers Dis 2015; 47:977-84. [PMID: 26401776 DOI: 10.3233/jad-140519] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The apolipoprotein E (APOE) ɛ4 allele is the best established genetic risk factor for Alzheimer's disease (AD) and has been previously associated with alterations in structural gray matter and changes in functional brain activity in healthy middle-aged individuals and older non-demented subjects. In order to determine the neural mechanism by which APOE polymorphisms affect white matter (WM) structure, we investigated the diffusion characteristics of WM tracts in carriers and non-carriers of the APOE ɛ4 and ɛ2 alleles using an unbiased whole brain analysis technique (Tract Based Spatial Statistics) in a healthy young adolescent (14 years) cohort. A large sample of healthy young adolescents (n = 575) were selected from the European neuroimaging-genetics IMAGEN study with available APOE status and accompanying diffusion imaging data. MR Diffusion data was acquired on 3T systems using 32 diffusion-weighted (DW) directions and 4 non-DW volumes (b-value = 1,300 s/mm² and isotropic resolution of 2.4×2.4×2.4 mm). No significant differences in WM structure were found in diffusion indices between carriers and non-carriers of the APOE ɛ4 and ɛ2 alleles, and dose-dependent effects of these variants were not established, suggesting that differences in WM structure are not modulated by the APOE polymorphism. In conclusion, our results suggest that microstructural properties of WM structure are not associated with the APOE ɛ4 and ɛ2 alleles in young adolescence, suggesting that the neural effects of these variants are not evident in 14-year-olds and may only develop later in life.
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Affiliation(s)
- Flavio Dell'Acqua
- King's College London, Institute of Psychiatry, London, UK
- NIHR Biomedical Research Centre for Mental Health, King's College London, London, UK
- NIHR Biomedical Research Unit for Dementia, King's College London, London, UK
| | - Wasim Khan
- King's College London, Institute of Psychiatry, London, UK
- NIHR Biomedical Research Centre for Mental Health, King's College London, London, UK
- NIHR Biomedical Research Unit for Dementia, King's College London, London, UK
| | - Natalie Gottlieb
- King's College London, Institute of Psychiatry, London, UK
- NIHR Biomedical Research Centre for Mental Health, King's College London, London, UK
- NIHR Biomedical Research Unit for Dementia, King's College London, London, UK
| | | | - Cedric Ginestet
- King's College London, Institute of Psychiatry, London, UK
- NIHR Biomedical Research Centre for Mental Health, King's College London, London, UK
| | - David Bouls
- King's College London, Institute of Psychiatry, London, UK
- NIHR Biomedical Research Centre for Mental Health, King's College London, London, UK
- NIHR Biomedical Research Unit for Dementia, King's College London, London, UK
| | - Steven Newhouse
- King's College London, Institute of Psychiatry, London, UK
- NIHR Biomedical Research Centre for Mental Health, King's College London, London, UK
- NIHR Biomedical Research Unit for Dementia, King's College London, London, UK
| | - Richard Dobson
- King's College London, Institute of Psychiatry, London, UK
- NIHR Biomedical Research Centre for Mental Health, King's College London, London, UK
- NIHR Biomedical Research Unit for Dementia, King's College London, London, UK
| | - Tobias Banaschewski
- Central Institute of Mental Health, Mannheim, Germany
- Medical Faculty Mannheim, University of Heidelberg, Germany
| | | | - Arun L W Bokde
- Institute of Neuroscience and Discipline of Psychiatry, School of Medicine, Trinity College Dublin, Dublin, Ireland
| | | | - Patricia Conrod
- King's College London, Institute of Psychiatry, London, UK
- Department of Psychiatry, Universite de Montreal, CHU Ste Justine Hospital, Canada
| | - Herta Flor
- Central Institute of Mental Health, Mannheim, Germany
- Medical Faculty Mannheim, University of Heidelberg, Germany
| | - Vincent Frouin
- Neurospin, Commissariat à l'Energie Atomique et aux Energies Alternatives, Paris, France
| | - Hugh Garavan
- Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
- Departments of Psychiatry and Psychology, University of Vermont, Burlington, VT, USA
| | - Penny Gowland
- School of Physics and Astronomy, University of Nottingham, Nottingham, UK
| | - Anreas Heinz
- Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité - Universitätsmedizin Berlin, Germany
| | - Hervé Lemaítre
- Institut National de la Santé et de la Recherche Médicale, INSERM CEA Unit 1000 "Imaging & Psychiatry", University Paris Sud, Orsay, and AP-HP Department of Adolescent Psychopathology and Medicine, Maison de Solenn, University Paris Descartes, Paris, France
| | - Frauke Nees
- Central Institute of Mental Health, Mannheim, Germany
- Medical Faculty Mannheim, University of Heidelberg, Germany
| | - Tomas Paus
- Rotman Research Institute, University of Toronto, Toronto, Canada
- School of Psychology, University of Nottingham, Nottingham, UK
- Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Zdenka Pausova
- The Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - Marcella Rietschel
- Central Institute of Mental Health, Mannheim, Germany
- Medical Faculty Mannheim, University of Heidelberg, Germany
| | - Michael N Smolka
- Neuroimaging Center, Department of Psychiatry and Psychotherapy, Technische Universität Dresden, Germany
| | - Andreas Ströhle
- Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité - Universitätsmedizin Berlin, Germany
| | - Jean Gallinat
- Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité - Universitätsmedizin Berlin, Germany
| | | | - Gunther Schumann
- King's College London, Institute of Psychiatry, London, UK
- NIHR Biomedical Research Centre for Mental Health, King's College London, London, UK
| | - Simon Lovestone
- King's College London, Institute of Psychiatry, London, UK
- NIHR Biomedical Research Centre for Mental Health, King's College London, London, UK
- NIHR Biomedical Research Unit for Dementia, King's College London, London, UK
| | - Andrew Simmons
- King's College London, Institute of Psychiatry, London, UK
- NIHR Biomedical Research Centre for Mental Health, King's College London, London, UK
- NIHR Biomedical Research Unit for Dementia, King's College London, London, UK
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14
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Li W, Antuono PG, Xie C, Chen G, Jones JL, Ward BD, Singh SP, Franczak MB, Goveas JS, Li SJ. Aberrant functional connectivity in Papez circuit correlates with memory performance in cognitively intact middle-aged APOE4 carriers. Cortex 2014; 57:167-76. [PMID: 24905971 DOI: 10.1016/j.cortex.2014.04.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 03/24/2014] [Accepted: 04/07/2014] [Indexed: 10/25/2022]
Abstract
The main objective of this study is to detect the early changes in resting-state Papez circuit functional connectivity using the hippocampus as the seed, and to determine the associations between altered functional connectivity (FC) and the episodic memory performance in cognitively intact middle-aged apolipoprotein E4 (APOE4) carriers who are at risk of Alzheimer's disease (AD). Forty-six cognitively intact, middle-aged participants, including 20 APOE4 carriers and 26 age-, sex-, and education-matched noncarriers were studied. The resting-state FC of the hippocampus (HFC) was compared between APOE4 carriers and noncarriers. APOE4 carriers showed significantly decreased FC in brain areas that involve learning and memory functions, including the frontal, cingulate, thalamus and basal ganglia regions. Multiple linear regression analysis showed significant correlations between HFC and the episodic memory performance. Conjunction analysis between neural correlates of memory and altered HFC showed the overlapping regions, especially the subcortical regions such as thalamus, caudate nucleus, and cingulate cortices involved in the Papez circuit. Thus, changes in connectivity in the Papez circuit may be used as an early risk detection for AD.
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Affiliation(s)
- Wenjun Li
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI, USA.
| | - Piero G Antuono
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA.
| | - Chunming Xie
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI, USA.
| | - Gang Chen
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI, USA.
| | - Jennifer L Jones
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA.
| | - B Douglas Ward
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI, USA.
| | - Suraj P Singh
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA
| | | | - Joseph S Goveas
- Department of Psychiatry and Behavioral Medicine, Medical College of Wisconsin, Milwaukee, WI, USA.
| | - Shi-Jiang Li
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI, USA; Department of Psychiatry and Behavioral Medicine, Medical College of Wisconsin, Milwaukee, WI, USA.
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15
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Zetzsche T, Rujescu D, Hardy J, Hampel H. Advances and perspectives from genetic research: development of biological markers in Alzheimer’s disease. Expert Rev Mol Diagn 2014; 10:667-90. [PMID: 20629514 DOI: 10.1586/erm.10.48] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Thomas Zetzsche
- Department of Psychiatry and Psychotherapy, Ludwig-Maximilian-University, Nussbaumstrasse 7, Munich, Germany. thomas.zetzsche@ med.uni-muenchen.de
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16
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Braskie MN, Toga AW, Thompson PM. Recent advances in imaging Alzheimer's disease. J Alzheimers Dis 2013; 33 Suppl 1:S313-27. [PMID: 22672880 DOI: 10.3233/jad-2012-129016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Advances in brain imaging technology in the past five years have contributed greatly to the understanding of Alzheimer's disease (AD). Here, we review recent research related to amyloid imaging, new methods for magnetic resonance imaging analyses, and statistical methods. We also review research that evaluates AD risk factors and brain imaging, in the context of AD prediction and progression. We selected a variety of illustrative studies, describing how they advanced the field and are leading AD research in promising new directions.
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Affiliation(s)
- Meredith N Braskie
- Laboratory of Neuro Imaging, Department of Neurology, UCLA School of Medicine, Los Angeles, CA 90095-7334, USA
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17
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Thambisetty M, Beason-Held LL, An Y, Kraut M, Nalls M, Hernandez DG, Singleton AB, Zonderman AB, Ferrucci L, Lovestone S, Resnick SM. Alzheimer risk variant CLU and brain function during aging. Biol Psychiatry 2013; 73:399-405. [PMID: 22795969 PMCID: PMC3488132 DOI: 10.1016/j.biopsych.2012.05.026] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Revised: 04/26/2012] [Accepted: 05/30/2012] [Indexed: 10/28/2022]
Abstract
BACKGROUND We examined the effect of the novel Alzheimer's disease (AD) risk variant rs11136000 single nucleotide polymorphism in the clusterin gene (CLU) on longitudinal changes in resting state regional cerebral blood flow (rCBF) during normal aging and investigated its influence on cognitive decline in presymptomatic stages of disease progression. METHODS Subjects were participants in the Baltimore Longitudinal Study of Aging. A subset of 88 cognitively normal older individuals had longitudinal (15)O-water positron emission tomography measurements of rCBF at baseline and up to eight annual follow-up visits. We also analyzed trajectories of cognitive decline among CLU risk carriers and noncarriers in individuals who remained cognitively normal (n = 599), as well as in those who subsequently converted to mild cognitive impairment or AD (n = 95). RESULTS Cognitively normal carriers of the CLU risk allele showed significant and dose-dependent longitudinal increases in resting state rCBF in brain regions intrinsic to memory processes. There were no differences in trajectories of memory performance between CLU risk carriers and noncarriers who remained cognitively normal. However, in cognitively normal individuals who eventually converted to mild cognitive impairment or AD, CLU risk carriers showed faster rates of decline in memory performance relative to noncarriers in the presymptomatic stages of disease progression. CONCLUSIONS The AD risk variant CLU influences longitudinal changes in brain function in asymptomatic individuals and is associated with faster cognitive decline in presymptomatic stages of disease progression. These results suggest mechanisms underlying the role of CLU in AD and may be important in monitoring disease progression in at-risk elderly.
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Affiliation(s)
- Madhav Thambisetty
- Laboratory of Behavioral Neuroscience, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224, USA.
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18
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Risacher SL, Wudunn D, Pepin SM, MaGee TR, McDonald BC, Flashman LA, Wishart HA, Pixley HS, Rabin LA, Paré N, Englert JJ, Schwartz E, Curtain JR, West JD, O'Neill DP, Santulli RB, Newman RW, Saykin AJ. Visual contrast sensitivity in Alzheimer's disease, mild cognitive impairment, and older adults with cognitive complaints. Neurobiol Aging 2012; 34:1133-44. [PMID: 23084085 DOI: 10.1016/j.neurobiolaging.2012.08.007] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 07/15/2012] [Accepted: 08/09/2012] [Indexed: 10/27/2022]
Abstract
Deficits in contrast sensitivity (CS) have been reported in Alzheimer's disease (AD). However, the extent of these deficits in prodromal AD stages, including mild cognitive impairment (MCI) or even earlier, has not been investigated. In this study, CS was assessed using frequency doubling technology in older adults with AD (n = 10), amnestic MCI (n = 28), cognitive complaints without performance deficits (CC; n = 20), and healthy controls (HC; n = 29). The association between CS and cognition was also evaluated. Finally, the accuracy of CS measures for classifying MCI versus HC was evaluated. CS deficits were found in AD and MCI, while CC showed intermediate performance between MCI and HC. Upper right visual field CS showed the most significant difference among groups. CS was also associated with cognitive performance. Finally, CS measures accurately classified MCI versus HC. The CS deficits in AD and MCI, and intermediate performance in CC, indicate that these measures are sensitive to early AD-associated changes. Therefore, frequency doubling technology-based measures of CS may have promise as a novel AD biomarker.
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Affiliation(s)
- Shannon L Risacher
- Center for Neuroimaging, Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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19
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Braskie MN, Ringman JM, Thompson PM. Neuroimaging measures as endophenotypes in Alzheimer's disease. Int J Alzheimers Dis 2011; 2011:490140. [PMID: 21547229 PMCID: PMC3087508 DOI: 10.4061/2011/490140] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 01/08/2011] [Accepted: 02/07/2011] [Indexed: 01/06/2023] Open
Abstract
Late onset Alzheimer's disease (AD) is moderately to highly heritable. Apolipoprotein E allele ε4 (APOE4) has been replicated consistently as an AD risk factor over many studies, and recently confirmed variants in other genes such as CLU, CR1, and PICALM each increase the lifetime risk of AD. However, much of the heritability of AD remains unexplained. AD is a complex disease that is diagnosed largely through neuropsychological testing, though neuroimaging measures may be more sensitive for detecting the incipient disease stages. Difficulties in early diagnosis and variable environmental contributions to the disease can obscure genetic relationships in traditional case-control genetic studies. Neuroimaging measures may be used as endophenotypes for AD, offering a reliable, objective tool to search for possible genetic risk factors. Imaging measures might also clarify the specific mechanisms by which proposed risk factors influence the brain.
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Affiliation(s)
- Meredith N Braskie
- Laboratory of Neuro Imaging, Department of Neurology, UCLA School of Medicine, 635 Charles Young Drive South, Suite 225, Los Angeles, CA 90095, USA
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20
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Ryan L, Walther K, Bendlin BB, Lue LF, Walker DG, Glisky EL. Age-related differences in white matter integrity and cognitive function are related to APOE status. Neuroimage 2011; 54:1565-77. [PMID: 20804847 PMCID: PMC2997188 DOI: 10.1016/j.neuroimage.2010.08.052] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Revised: 07/16/2010] [Accepted: 08/19/2010] [Indexed: 11/17/2022] Open
Abstract
While an extensive literature is now available on age-related differences in white matter integrity measured by diffusion MRI, relatively little is known about the relationships between diffusion and cognitive functions in older adults. Even less is known about whether these relationships are influenced by the apolipoprotein (APOE) ε4 allele, despite growing evidence that ε4 increases cognitive impairment in older adults. The purpose of the present study was to examine these relationships in a group of community-dwelling cognitively normal older adults. Data were obtained from a sample of 126 individuals (ages 52-92) that included 32 ε4 heterozygotes, 6 ε4 homozygotes, and 88 noncarriers. Two measures of diffusion, the apparent diffusion coefficient (ADC) and fractional anisotropy (FA), were obtained from six brain regions-frontal white matter, lateral parietal white matter, the centrum semiovale, the genu and splenium of the corpus callosum, and the temporal stem white matter-and were used to predict composite scores of cognitive function in two domains, executive function and memory function. Results indicated that ADC and FA differed with increasing age in all six brain regions, and these differences were significantly greater for ε4 carriers compared to noncarriers. Importantly, after controlling for age, diffusion measures predicted cognitive function in a region-specific way that was also influenced by ε4 status. Regardless of APOE status, frontal ADC and FA independently predicted executive function scores for all participants, while temporal lobe ADC additionally predicted executive function for ε4 carriers but not noncarriers. Memory scores were predicted by temporal lobe ADC but not frontal diffusion for all participants, and this relationship was significantly stronger in ε4 carriers compared to noncarriers. Taken together, age and temporal lobe ADC accounted for a striking 53% of the variance in memory scores within the ε4 carrier group. The results provide further evidence that APOE ε4 has a significant impact on the trajectory of age-related cognitive functioning in older adults. Possible mechanisms are discussed that could account for the associations between ε4, diffusion, and cognitive function, including the influence of ε4 on neural repair, oxidative stress, and the health of myelin-producing oligodendroglia.
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Affiliation(s)
- Lee Ryan
- Evelyn F. McKnight Brain Institute, Department of Psychology, University of Arizona, Tucson, AZ 85721-0068, USA.
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21
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Thambisetty M, Beason-Held L, An Y, Kraut MA, Resnick SM. APOE epsilon4 genotype and longitudinal changes in cerebral blood flow in normal aging. ACTA ACUST UNITED AC 2010; 67:93-8. [PMID: 20065135 DOI: 10.1001/archneurol.2009.913] [Citation(s) in RCA: 146] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVE To study differences in longitudinal changes in regional cerebral blood flow (rCBF) between apolipoprotein E (APOE) epsilon4 carriers and noncarriers in nondemented older adults from the Baltimore Longitudinal Study of Aging using positron emission tomography in order to determine whether there are regionally specific longitudinal changes in rCBF in APOE epsilon4 carriers that might be related to its well-established role as a genetic risk factor for Alzheimer disease. DESIGN, SETTING, AND PARTICIPANTS Using oxygen 15 ([(15)O])-labeled water positron emission tomography and voxel-based analysis, we compared changes in rCBF over an 8-year period between 29 nondemented APOE epsilon4 carriers and 65 noncarriers older than 55 years. Serial neuropsychological data were collected for all participants. RESULTS Widespread differences were observed in longitudinal change in rCBF between epsilon4 carriers and noncarriers. The predominant pattern was greater rCBF decline in epsilon4 carriers. These differences were observed in the frontal, parietal, and temporal cortices. The affected brain regions were those especially vulnerable to pathological changes in Alzheimer disease. Both epsilon4 carriers and noncarriers remained free of clinical diagnoses of dementia or mild cognitive impairment during the course of the study. CONCLUSIONS Our findings suggest that APOE epsilon4-mediated risk for Alzheimer disease is associated with widespread decline in rCBF over time that precedes the onset of dementia. Accelerated rates of decline in brain function in APOE epsilon4 carriers may contribute to an increased risk for Alzheimer disease and a younger age at onset.
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Affiliation(s)
- Madhav Thambisetty
- Department of Radiology and Radiological Sciences, Laboratory of Personality and Cognition, National Institute on Aging, National Institutes of Health, Johns Hopkins University, Baltimore, Maryland 21224-6825, USA.
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22
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Abstract
INTRODUCTION Cerebral perfusion imaging using magnetic resonance imaging (MRI) is widely used in the research and clinical fields to assess the profound changes in blood flow related to ischemic events such as acute stroke, chronic steno-occlusive disease, vasospasm, and abnormal vessel formations from congenital conditions or tumoral neovascularity. With continuing improvements in the precision of MRI-based perfusion techniques, it is increasingly feasible to use this tool in the study of the subtle brain perfusion changes occurring in psychiatric illnesses. This article aims to review the existing literature on applications of perfusion MRI in psychiatric disorder and substance abuse research. The article also provides a brief introductory overview of dynamic susceptibility contrast MRI and arterial spin labeling techniques. An outlook of necessary steps to bring perfusion MRI into the realm of clinical psychiatry as a diagnostic tool is brought forth. Opportunities for research in unexplored disorders and with higher field strengths are briefly examined. METHODS PubMed, ISI Web of Knowledge & Scopus were used to search the literature and cross reference several neuropsychiatric disorders with a search term construct, including "magnetic resonance imaging," "dynamic susceptibility contrast," "arterial spin labeling," perfusion or "cerebral blood flow" or "cerebral blood volume" or "mean transit time." The list of disorders used in the search included schizophrenia, depression and bipolar disorder, dementia and Alzheimer's disease, Parkinson's disease, posttraumatic stress disorder, autism, Asperger disease, attention deficit, Tourette syndrome, obsessive-compulsive disorder, Huntington's disease, bulimia nervosa, anorexia nervosa, and substance abuse. For each disorder for which perfusion MRI studies were found, a brief overview of the disorder symptoms, treatment, prevalence, and existing models is provided, and previous findings from nuclear medicine-based perfusion imaging are overviewed. Findings of perfusion MRI studies are then summarized, and overlap of findings are discussed. Overarching conclusions are made, or an outlook for future work in the area is offered, where appropriate. RESULTS Despite the now fairly broad availability of perfusion MRI, only a limited number of studies were found using this technology. The search produced 13 studies of schizophrenia, 7 studies in major depression, 12 studies in Alzheimer's disease, and 2 studies in Parkinson's disease. Drug abuse and other disorders have mainly been studied with nuclear medicine-based perfusion imaging. The literature concerning the use of perfusion imaging in psychiatry has not been reviewed in the last 5 years or more. The use of MRI for perfusion measurements in psychiatry has not been reviewed in 10 years. CONCLUSIONS Although MRI-based perfusion imaging in psychiatry has mainly been used as a research tool, a path is progressively being cleared for its application in clinical diagnostic and treatment monitoring. The precision of perfusion MRI methods now rivals that of nuclear medicine-based perfusion imaging techniques. Because of their noninvasive nature, arterial spin labeling methods have gained popularity in studies of neuropsychiatric disorders such as schizophrenia, depression, Alzheimer's, and Parkinson's diseases. Perfusion imaging measurements have yet to be included within the diagnostic criteria of neuropsychiatric disorders despite having shown to have great discriminant power in specific disorders. As this young methodology continues to improve and research studies demonstrate the correlation of measured perfusion abnormalities to microcirculatory abnormalities and neuropsychiatric symptomatology, the idea of including such a test within diagnostic criteria for certain mental illnesses becomes increasingly plausible.
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Negash S, Greenwood PM, Sunderland T, Parasuraman R, Geda YE, Knopman DS, Boeve BF, Ivnik RJ, Petersen RC, Smith GE. The influence of apolipoprotein E genotype on visuospatial attention dissipates after age 80. Neuropsychology 2009; 23:81-9. [PMID: 19210035 DOI: 10.1037/a0014014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Although it is established that apolipoprotein E (APOE) e4 allele increases the risk of Alzheimer's disease (AD), epidemiological studies indicate that genetic risk decreases late in life. This raises the question of whether the effects of APOE on cognition that are seen in midlife arise from a cognitive phenotype of APOE or from the presence of early AD in some APOE-e4 carriers. The authors addressed this question by comparing the cognitive consequences of variation in the APOE gene between individuals over the age of 80 (old-old) and middle-aged and young-old individuals. A spatially cued discrimination paradigm--previously shown to be sensitive to AD and to APOE genotype--required a speeded categorization of a target letter following cues that were valid, invalid, or neutral in predicting target location. Results revealed greater costs of invalid cues in the APOE-e4 carriers of middle-aged and young-old, but not old-old, groups. The dissipation of the APOE effect in old-old individuals at lower risk of AD suggests that visuospatial attention impairments seen as early as midlife in APOE-e4 carriers may be a preclinical marker of AD.
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24
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Abstract
Determining the brain properties that make people 'brainier' has moved well beyond early demonstrations that increasing intelligence correlates with increasing grey and white matter volumes. Both structural and functional in vivo neuroimaging techniques delineate a distributed network of brain regions, perhaps with a focus in the lateral prefrontal cortex, which varies in extent and connectivity with individual differences in intelligence. Longitudinal studies further show that the neuroanatomic correlates of intelligence are dynamic, changing most rapidly in early childhood. Several promising candidate genes affecting neuronal development and neurotransmission have been proposed that might begin to explain the marked genetic overlap between cortical morphology and intelligence. A major future challenge is to determine the cellular events that underpin the neuroanatomic differences correlated with intelligence.
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Affiliation(s)
- Philip Shaw
- 10 Center Drive, 3N202, Child Psychiatry Branch, NIMH, Bethesda, Maryland 20892-1600, USA.
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25
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Abstract
BACKGROUND We previously reported that the Mediterranean diet (MeDi) is related to lower risk for Alzheimer disease (AD). Whether MeDi is associated with subsequent AD course and outcomes has not been investigated. OBJECTIVES To examine the association between MeDi and mortality in patients with AD. METHODS A total of 192 community-based individuals in New York who were diagnosed with AD were prospectively followed every 1.5 years. Adherence to the MeDi (0- to 9-point scale with higher scores indicating higher adherence) was the main predictor of mortality in Cox models that were adjusted for period of recruitment, age, gender, ethnicity, education, APOE genotype, caloric intake, smoking, and body mass index. RESULTS Eighty-five patients with AD (44%) died during the course of 4.4 (+/-3.6, 0.2 to 13.6) years of follow-up. In unadjusted models, higher adherence to MeDi was associated with lower mortality risk (for each additional MeDi point hazard ratio 0.79; 95% CI 0.69 to 0.91; p = 0.001). This result remained significant after controlling for all covariates (0.76; 0.65 to 0.89; p = 0.001). In adjusted models, as compared with AD patients at the lowest MeDi adherence tertile, those at the middle tertile had lower mortality risk (0.65; 0.38 to 1.09; 1.33 years' longer survival), whereas subjects at the highest tertile had an even lower risk (0.27; 0.10 to 0.69; 3.91 years' longer survival; p for trend = 0.003). CONCLUSION Adherence to the Mediterranean diet (MeDi) may affect not only risk for Alzheimer disease (AD) but also subsequent disease course: Higher adherence to the MeDi is associated with lower mortality in AD. The gradual reduction in mortality risk for higher MeDi adherence tertiles suggests a possible dose-response effect.
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Affiliation(s)
- Nikolaos Scarmeas
- Taub Institute for Research in Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, NY 10032, USA.
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26
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Smith GS, Gunning-Dixon FM, Lotrich FE, Taylor WD, Evans JD. Translational research in late-life mood disorders: implications for future intervention and prevention research. Neuropsychopharmacology 2007; 32:1857-75. [PMID: 17327888 DOI: 10.1038/sj.npp.1301333] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Clinical and epidemiological studies have consistently observed the heterogeneous symptomatology and course of geriatric depression. Given the importance of genetic and environmental risk factors, aging processes, neurodegenerative and cerebrovascular disease processes, and medical comorbidity, the integration of basic and clinical neuroscience research approaches is critical for the understanding of the variability in illness course, as well as the development of prevention and intervention strategies that are more effective. These considerations were the impetus for a workshop, sponsored by the Geriatrics Research Branch in the Division of Adult Translational Research and Treatment Development of the National Institute of Mental Health that was held on September 7-8, 2005. The primary goal of the workshop was to bring together investigators in geriatric psychiatry research with researchers in specific topic areas outside of geriatric mental health to identify priority areas to advance translational research in geriatric depression. As described in this report, the workshop focused on a discussion of the development and application of integrative approaches combining genetics and neuroimaging methods to understand such complex issues as treatment response variability, the role of medical comorbidity in depression, and the potential overlap between depression and dementia. Future directions for integrative research were identified. Understanding the nature of geriatric depression requires the application of translational research and interdisciplinary research approaches. Geriatric depression could serve as a model for translational research integrating basic and clinical neuroscience approaches that would have implications for the study of other neuropsychiatric disorders.
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Affiliation(s)
- Gwenn S Smith
- PET Centre, Centre for Addiction and Mental Health, Department of Psychiatry, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
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27
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Dickerson BC. The entorhinal cortex: an anatomical mediator of genetic vulnerability to Alzheimer's disease? Lancet Neurol 2007; 6:471-3. [PMID: 17509474 DOI: 10.1016/s1474-4422(07)70112-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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