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Jang JY, Beam CR, Karlsson IK, Pedersen NL, Gatz M. Dementia and mortality in older adults: A twin study. Alzheimers Dement 2024; 20:1682-1692. [PMID: 38078564 PMCID: PMC10947969 DOI: 10.1002/alz.13553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 09/28/2023] [Accepted: 10/22/2023] [Indexed: 12/17/2023]
Abstract
INTRODUCTION Dementia predicts increased mortality. We used case-control and co-twin control models to investigate genetic and shared environmental influences on this association. METHODS Case-control design, including 987 twins with dementia and 2938 age- and sex-matched controls in the Swedish Twin Registry. Co-twin control design, including 90 monozygotic (MZ) and 288 dizygotic (DZ) twin pairs discordant for dementia. To test for genetic and environmental confounding, differences were examined in mortality risk between twins with dementia and their matched or co-twin controls. RESULTS Twins with dementia showed greater mortality risk than age- and sex-matched controls (HR = 2.02 [1.86, 2.18]). Mortality risk is significantly elevated but attenuated substantially in discordant twin pairs, for example, comparing MZ twins with dementia to their co-twin controls (HR = 1.48 [1.08, 2.04]). DISCUSSION Findings suggest that genetic factors partially confound the association between dementia and mortality and provide an alternative hypothesis to increased mortality due to dementia itself. Highlights We studied dementia and mortality in twin pairs discordant for dementia. People without dementia outlived people with dementia. Identical twins with dementia and their co-twin controls had similar survival time. Findings suggest genotype may explain the link between dementia and mortality.
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Affiliation(s)
- Jung Yun Jang
- Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, California, USA
| | - Christopher R Beam
- Department of Psychology, University of Southern California, Los Angeles, California, USA
- Davis School of Gerontology, University of Southern California, Los Angeles, California, USA
| | - Ida K Karlsson
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - Nancy L Pedersen
- Department of Psychology, University of Southern California, Los Angeles, California, USA
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - Margaret Gatz
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
- Center for Economic and Social Research, University of Southern California, Los Angeles, California, USA
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Thompson LI, Cummings M, Emrani S, Libon DJ, Ang A, Karjadi C, Au R, Liu C. Digital Clock Drawing as an Alzheimer's Disease Susceptibility Biomarker: Associations with Genetic Risk Score and APOE in Older Adults. J Prev Alzheimers Dis 2024; 11:79-87. [PMID: 38230720 PMCID: PMC10794851 DOI: 10.14283/jpad.2023.48] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
BACKGROUND Alzheimer's disease (AD) is the leading cause of dementia in older adults, but most people are not diagnosed until significant neuronal loss has likely occurred along with a decline in cognition. Non-invasive and cost-effective digital biomarkers for AD have the potential to improve early detection. OBJECTIVE We examined the validity of DCTclockTM (a digitized clock drawing task) as an AD susceptibility biomarker. DESIGN We used two primary independent variables, Apolipoprotein E (APOE) ε4 allele carrier status and polygenic risk score (PRS). We examined APOE and PRS associations with DCTclockTM composite scores as dependent measures. SETTING We used existing data from the Framingham Heart Study (FHS), a community-based study with the largest dataset of digital clock drawing data to date. PARTICIPANTS The sample consisted of 2,398 older adults ages 60-94 with DCTclockTM data (mean age of 72.3, 55% female and 92% White). MEASUREMENTS PRS was calculated using 38 variants identified in a recent large genome-wide association study (GWAS) and meta-analysis of late-onset AD (LOAD). RESULTS Results showed that DCTclockTM performance decreased with advancing age, lower education, and the presence of one or more copies of APOE ε4. Lower DCTclockTM Total Score as well as lower composite scores for Information Processing Speed (both command and copy conditions) and Drawing Efficiency (command condition) were significantly associated with higher PRS levels and more copies of APOE ε4. APOE and PRS associations displayed similar effect sizes in both men and women. CONCLUSIONS Our results indicate that higher AD genetic risk is associated with poorer DCTclockTM performance in older adults without dementia. This is the first study to demonstrate significant differences in clock drawing performance on the basis of APOE status or PRS.
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Affiliation(s)
- L I Thompson
- Louisa Thompson, Department of Psychiatry, Alpert Medical School, Brown University, Providence, RI. Address: 345 Blackstone Blvd., Providence, RI 02906, USA. Phone: 401-455-6402. E-mail:
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Beam CR, Luczak SE, Panizzon MS, Reynolds CA, Christensen K, Dahl Aslan AK, Elman JA, Franz CE, Kremen WS, Lee T, Nygaard M, Sachdev PS, Whitfield KE, Pedersen NL, Gatz M. Estimating Likelihood of Dementia in the Absence of Diagnostic Data: A Latent Dementia Index in 10 Genetically Informed Studies. J Alzheimers Dis 2022; 90:1187-1201. [PMID: 36213997 PMCID: PMC9741742 DOI: 10.3233/jad-220472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND Epidemiological research on dementia is hampered by differences across studies in how dementia is classified, especially where clinical diagnoses of dementia may not be available. OBJECTIVE We apply structural equation modeling to estimate dementia likelihood across heterogeneous samples within a multi-study consortium and use the twin design of the sample to validate the results. METHODS Using 10 twin studies, we implement a latent variable approach that aligns different tests available in each study to assess cognitive, memory, and functional ability. The model separates general cognitive ability from components indicative of dementia. We examine the validity of this continuous latent dementia index (LDI). We then identify cut-off points along the LDI distributions in each study and align them across studies to distinguish individuals with and without probable dementia. Finally, we validate the LDI by determining its heritability and estimating genetic and environmental correlations between the LDI and clinically diagnosed dementia where available. RESULTS Results indicate that coordinated estimation of LDI across 10 studies has validity against clinically diagnosed dementia. The LDI can be fit to heterogeneous sets of memory, other cognitive, and functional ability variables to extract a score reflective of likelihood of dementia that can be interpreted similarly across studies despite diverse study designs and sampling characteristics. Finally, the same genetic sources of variance strongly contribute to both the LDI and clinical diagnosis. CONCLUSION This latent dementia indicator approach may serve as a model for other research consortia confronted with similar data integration challenges.
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Affiliation(s)
- Christopher R. Beam
- Department of Psychology, University of Southern California, Los Angeles, CA, USA
| | - Susan E. Luczak
- Department of Psychology, University of Southern California, Los Angeles, CA, USA
| | - Matthew S. Panizzon
- Department of Psychiatry and Center for Behavior Genetics of Aging, University of California San Diego, San Diego, CA, USA
| | - Chandra A. Reynolds
- Department of Psychology, University of California Riverside, Riverside, CA, USA
| | - Kaare Christensen
- The Danish Twin Registry, University of Southern Denmark, Odense, Denmark
| | - Anna K. Dahl Aslan
- School of Health Sciences, University of Skövde, Skövde, Sweden,
Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Solna, Sweden
| | - Jeremy A. Elman
- Department of Psychiatry and Center for Behavior Genetics of Aging, University of California San Diego, San Diego, CA, USA
| | - Carol E. Franz
- Department of Psychiatry and Center for Behavior Genetics of Aging, University of California San Diego, San Diego, CA, USA
| | - William S. Kremen
- Department of Psychiatry and Center for Behavior Genetics of Aging, University of California San Diego, San Diego, CA, USA
| | - Teresa Lee
- Centre for Healthy Brain Ageing (CHeBA), University of New South Wales, Sydney, Australia
| | - Marianne Nygaard
- The Danish Twin Registry, University of Southern Denmark, Odense, Denmark
| | - Perminder S. Sachdev
- Centre for Healthy Brain Ageing (CHeBA), University of New South Wales, Sydney, Australia
| | - Keith E. Whitfield
- Department of Psychology, University of Nevada LasVegas, Las Vegas, Nevada
| | - Nancy L. Pedersen
- Department of Psychology, University of Southern California, Los Angeles, CA, USA,
Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Solna, Sweden
| | - Margaret Gatz
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Solna, Sweden,
Center for Economic and Social Research, University of Southern California, Los Angeles, CA, USA,Correspondence to: Margaret Gatz, Center for Economic and Social Research, University of Southern California, Los Angeles, CA, USA. Tel.: +1 213 740 2212; E-mail:
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Karlsson IK, Escott-Price V, Gatz M, Hardy J, Pedersen NL, Shoai M, Reynolds CA. Measuring heritable contributions to Alzheimer's disease: polygenic risk score analysis with twins. Brain Commun 2022; 4:fcab308. [PMID: 35169705 PMCID: PMC8833403 DOI: 10.1093/braincomms/fcab308] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 09/17/2021] [Accepted: 10/18/2021] [Indexed: 11/23/2022] Open
Abstract
The heritability of Alzheimer's disease estimated from twin studies is greater than the heritability derived from genome-based studies, for reasons that remain unclear. We apply both approaches to the same twin sample, considering both Alzheimer's disease polygenic risk scores and heritability from twin models, to provide insight into the role of measured genetic variants and to quantify uncaptured genetic risk. A population-based heritability and polygenic association study of Alzheimer's disease was conducted between 1986 and 2016 and is the first study to incorporate polygenic risk scores into biometrical twin models of Alzheimer's disease. The sample included 1586 twins drawn from the Swedish Twin Registry which were nested within 1137 twin pairs (449 complete pairs and 688 incomplete pairs) with clinically based diagnoses and registry follow-up (M age = 85.28, SD = 7.02; 44% male; 431 cases and 1155 controls). We report contributions of polygenic risk scores at P < 1 × 10-5, considering a full polygenic risk score (PRS), PRS without the APOE region (PRS.no.APOE) and PRS.no.APOE plus directly measured APOE alleles. Biometric twin models estimated the contribution of environmental influences and measured (PRS) and unmeasured genes to Alzheimer's disease risk. The full PRS and PRS.no.APOE contributed 10.1 and 2.4% to Alzheimer's disease risk, respectively. When APOE ɛ4 alleles were added to the model with the PRS.no.APOE, the total contribution was 11.4% to Alzheimer's disease risk, where APOE ɛ4 explained 9.3% and PRS.no.APOE dropped from 2.4 to 2.1%. The total genetic contribution to Alzheimer's disease risk, measured and unmeasured, was 71% while environmental influences unique to each twin accounted for 29% of the risk. The APOE region accounts for much of the measurable genetic contribution to Alzheimer's disease, with a smaller contribution from other measured polygenic influences. Importantly, substantial background genetic influences remain to be understood.
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Affiliation(s)
- Ida K. Karlsson
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
- Aging Research Network—Jönköping (ARN-J), School of Health and 6 Welfare, Jönköping University, Jönköping, Sweden
| | - Valentina Escott-Price
- UK Dementia Research Institute at Cardiff, Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, Cardiff, UK
| | - Margaret Gatz
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
- Center for Economic and Social Research, University of Southern California, Los Angeles, CA, USA
| | - John Hardy
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, UK
- UK Dementia Research Institute at UCL and Department of Neurodegenerative Disease, UCL Institute of Neurology, University College London, London, UK
- Reta Lila Weston Institute, UCL Queen Square Institute of Neurology, 1 Wakefield Street, London WC1N 1PJ, UK
- UCL Movement Disorders Centre, University College London, London, UK
- Institute for Advanced Study, The Hong Kong University of Science and Technology, Hong Kong SAR, China
| | - Nancy L. Pedersen
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
- Department of Psychology, University of Southern California, Los Angeles, CA, USA
| | - Maryam Shoai
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, UK
- UK Dementia Research Institute at UCL and Department of Neurodegenerative Disease, UCL Institute of Neurology, University College London, London, UK
| | - Chandra A. Reynolds
- Department of Psychology, University of California—Riverside, Riverside, CA, USA
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Jack CR, Therneau TM, Lundt ES, Wiste HJ, Mielke MM, Knopman DS, Graff-Radford J, Lowe VJ, Vemuri P, Schwarz CG, Senjem ML, Gunter JL, Petersen RC. OUP accepted manuscript. Brain Commun 2022; 4:fcac017. [PMID: 35310829 PMCID: PMC8924651 DOI: 10.1093/braincomms/fcac017] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 11/08/2021] [Accepted: 01/31/2022] [Indexed: 11/14/2022] Open
Affiliation(s)
- Clifford R. Jack
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
- Correspondence to: Clifford R. Jack Jr, MD 200 First St SW Rochester, MN 55905, USA E-mail:
| | - Terry M. Therneau
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, USA
| | - Emily S. Lundt
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, USA
| | - Heather J. Wiste
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, USA
| | - Michelle M. Mielke
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, USA
| | | | | | - Val J. Lowe
- Department of Nuclear Medicine, Mayo Clinic, Rochester, MN, USA
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Udeh-Momoh C, Watermeyer T. Female specific risk factors for the development of Alzheimer's disease neuropathology and cognitive impairment: Call for a precision medicine approach. Ageing Res Rev 2021; 71:101459. [PMID: 34508876 DOI: 10.1016/j.arr.2021.101459] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 08/13/2021] [Accepted: 09/06/2021] [Indexed: 12/14/2022]
Abstract
Alzheimer's disease (AD) includes a long asymptomatic stage, which precedes the formal diagnosis of dementia. AD biomarker models provide a framework for precision medicine approaches during this stage. However, such approaches have ignored the possible influence of sex on cognition and brain health, despite female sex noted as a major risk factor. Since AD-related changes may emerge in midlife, intervention efforts are being redirected around this period. Midlife coincides with several endocrinological changes, such as the menopausal transition experienced by women. In this narrative review, we discuss evidence for sex-differences in AD neuropathological burden and outline key endocrinological mechanisms for both sexes, focussing on hormonal events throughout the lifespan that may influence female susceptibility to AD neuropathology and dementia onset. We further consider common non-modifiable (genetic) and modifiable (lifestyle and health) risk factors, highlighting possible sex-dependent differential effects for the AD disease course. Finally, we evaluate the studies selected for this review demonstrating sex-differences in cognitive, pathological and health factors, summarising the state of sex differences in AD risk factors. We further provide recommendations for targeted research on female-specific risk factors, to inform personalised strategies for AD-prevention and the promotion of female brain health.
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Kim AJ, Gold AI, Fenton L, Pilgrim MJD, Lynch M, Climer CR, Penichet EN, Kam A, Beam CR. A Genetically Informed Longitudinal Study of Loneliness and Dementia Risk in Older Adults. Front Genet 2021; 12:661474. [PMID: 34603367 PMCID: PMC8484886 DOI: 10.3389/fgene.2021.661474] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 07/30/2021] [Indexed: 11/29/2022] Open
Abstract
Although several studies have shown small longitudinal associations between baseline loneliness and subsequent dementia risk, studies rarely test whether change in loneliness predicts dementia risk. Furthermore, as both increase with advancing age, genetic and environmental selection processes may confound the putative causal association between loneliness and dementia risk. We used a sample of 2,476 individual twins from three longitudinal twin studies of aging in the Swedish Twin Registry to test the hypothesis that greater positive change in loneliness predicts greater dementia risk. We then used a sample of 1,632 pairs of twins to evaluate the hypothesis that effects of change in loneliness on dementia risk would remain after adjusting for effects of genetic and environmental variance. Phenotypic model results suggest that mild levels of baseline loneliness predict greater dementia risk. Contrary to our hypothesis, change in loneliness did not correlate with dementia risk, regardless of whether genetic and environmental selection confounds were taken into account. Worsening loneliness with age may not confer greater dementia risk.
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Affiliation(s)
- Alice J. Kim
- Department of Psychology, University of Southern California, Los Angeles, CA, United States
| | - Alaina I. Gold
- Department of Psychology, University of Southern California, Los Angeles, CA, United States
| | - Laura Fenton
- Department of Psychology, University of Southern California, Los Angeles, CA, United States
| | - Matthew J. D. Pilgrim
- Department of Psychology, University of Southern California, Los Angeles, CA, United States
| | - Morgan Lynch
- Department of Psychology, University of Southern California, Los Angeles, CA, United States
| | - Cailin R. Climer
- Department of Psychology, University of Southern California, Los Angeles, CA, United States
| | - Eric N. Penichet
- Department of Psychology, University of Southern California, Los Angeles, CA, United States
| | - Alyssa Kam
- Department of Psychology, University of Southern California, Los Angeles, CA, United States
| | - Christopher R. Beam
- Department of Psychology, University of Southern California, Los Angeles, CA, United States
- School of Gerontology, University of Southern California, Los Angeles, CA, United States
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GIPSON CD, BIMONTE-NELSON HA. Interactions between reproductive transitions during aging and addiction: promoting translational crosstalk between different fields of research. Behav Pharmacol 2021; 32:112-122. [PMID: 32960852 PMCID: PMC7965232 DOI: 10.1097/fbp.0000000000000591] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Discovery of neural mechanisms underlying neuropsychiatric disorders within the aging and addiction fields has been a main focus of the National Institutes of Health. However, there is a dearth of knowledge regarding the biological interactions of aging and addiction, which may have important influences on progression of disease and treatment outcomes in aging individuals with a history of chronic drug use. Thus, there is a large gap in these fields of research, which has slowed progress in understanding and treating substance use disorders (SUDs) as well as age-related diseases, specifically in women who experience precipitous reproductive cycle transitions during aging. The goal of this review is to highlight overlap of SUDs and age-related processes with a specific focus on menopause and smoking, and identify critical gaps. We have narrowed the focus of the review to smoking, as the majority of findings on hormonal and aging influences on drug use have come from this area of research. Further, we highlight female-specific issues such as transitional menopause and exogenous estrogen use. These issues may impact drug use cessation as well as outcomes with aging and age-related neurodegenerative diseases in women. We first review clinical studies for smoking, normal aging, and pathological aging, and discuss the few aging-related studies taking smoking history into account. Conversely, we highlight the dearth of clinical smoking studies taking age as a biological variable into account. Preclinical and clinical literature show that aging, age-related pathological brain disease, and addiction engage overlapping neural mechanisms. We hypothesize that these putative drivers interact in meaningful ways that may exacerbate disease and hinder successful treatment outcomes in such comorbid populations. We highlight areas where preclinical studies are needed to uncover neural mechanisms in aging and addiction processes. Collectively, this review highlights the need for crosstalk between different fields of research to address medical complexities of older adults, and specifically women, who smoke.
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Affiliation(s)
- Cassandra D. GIPSON
- Department of Family and Community Medicine, University of Kentucky, Lexington, KY
- Arizona Alzheimer’s Consortium
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Sabbagh MN, Pope E, Cordes L, Shi J, DeCourt B. Therapeutic considerations for APOE and TOMM40 in Alzheimers disease: A tribute to Allen Roses MD. Expert Opin Investig Drugs 2021; 30:39-44. [PMID: 33455481 PMCID: PMC9262379 DOI: 10.1080/13543784.2021.1849138] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 11/04/2020] [Indexed: 01/25/2023]
Abstract
Introduction: Four years ago this Autumn, pioneering neurologist Prof. Allen. D. Roses passed away. Hence, we have taken time to reflect on his work and legacy in Alzheimer's disease (AD) research. Prof. Roses rejected the widely accepted amyloid hypothesis, which identifies amyloid beta (Aβ) protein accumulation within the brain as the cause of AD. Instead, he proposed that the epsilon type 4 allele of apolipoprotein (APOE- Ɛ4) and translocase of outer mitochondrial membrane 40 homolog (TOMM40) were preeminent factors in the pathogenesis and progression of AD, particularly in late-onset AD (LOAD). This rejection of the amyloid hypothesis has generated new investigations into APOE and TOMM40 as risk factors for AD. Areas covered: We discuss the contributions of Prof. Roses to AD research, describe how APOE-Ɛ4 and TOMM40 have been posited to trigger neuropathological changes leading to AD, and explore paths to future clinical applications built on the foundations of his research. Expert opinion: The unconventional methodology of targeting APOE and TOMM40 offers great potential for the development of effective preventive and disease-modifying AD interventions. Future preclinical and clinical investigations will greatly benefit from the groundbreaking scientific discoveries of Prof. Roses.
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Affiliation(s)
| | - Evans Pope
- Cleveland Clinic, Lou Ruvo Center for Brain Health , Las Vegas, NV, USA
| | - Laura Cordes
- Cleveland Clinic, Lou Ruvo Center for Brain Health , Las Vegas, NV, USA
| | - Jiong Shi
- Cleveland Clinic, Lou Ruvo Center for Brain Health , Las Vegas, NV, USA
| | - Boris DeCourt
- Cleveland Clinic, Lou Ruvo Center for Brain Health , Las Vegas, NV, USA
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