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Cell models for Down syndrome-Alzheimer’s disease research. Neuronal Signal 2022; 6:NS20210054. [PMID: 35449591 PMCID: PMC8996251 DOI: 10.1042/ns20210054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 03/07/2022] [Accepted: 03/21/2022] [Indexed: 11/29/2022] Open
Abstract
Down syndrome (DS) is the most common chromosomal abnormality and leads to intellectual disability, increased risk of cardiac defects, and an altered immune response. Individuals with DS have an extra full or partial copy of chromosome 21 (trisomy 21) and are more likely to develop early-onset Alzheimer’s disease (AD) than the general population. Changes in expression of human chromosome 21 (Hsa21)-encoded genes, such as amyloid precursor protein (APP), play an important role in the pathogenesis of AD in DS (DS-AD). However, the mechanisms of DS-AD remain poorly understood. To date, several mouse models with an extra copy of genes syntenic to Hsa21 have been developed to characterise DS-AD-related phenotypes. Nonetheless, due to genetic and physiological differences between mouse and human, mouse models cannot faithfully recapitulate all features of DS-AD. Cells differentiated from human-induced pluripotent stem cells (iPSCs), isolated from individuals with genetic diseases, can be used to model disease-related cellular and molecular pathologies, including DS. In this review, we will discuss the limitations of mouse models of DS and how these can be addressed using recent advancements in modelling DS using human iPSCs and iPSC-mouse chimeras, and potential applications of iPSCs in preclinical studies for DS-AD.
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Pivtoraiko VN, Racic T, Abrahamson EE, Villemagne VL, Handen BL, Lott IT, Head E, Ikonomovic MD. Postmortem Neocortical 3H-PiB Binding and Levels of Unmodified and Pyroglutamate Aβ in Down Syndrome and Sporadic Alzheimer's Disease. Front Aging Neurosci 2021; 13:728739. [PMID: 34489686 PMCID: PMC8416541 DOI: 10.3389/fnagi.2021.728739] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 07/20/2021] [Indexed: 12/01/2022] Open
Abstract
Individuals with Down syndrome (DS) have a genetic predisposition for amyloid-β (Aβ) overproduction and earlier onset of Aβ deposits compared to patients with sporadic late-onset Alzheimer’s disease (AD). Positron emission tomography (PET) with Pittsburgh Compound-B (PiB) detects fibrillar Aβ pathology in living people with DS and AD, but its relationship with heterogeneous Aβ forms aggregated within amyloid deposits is not well understood. We performed quantitative in vitro3H-PiB binding assays and enzyme-linked immunosorbent assays of fibrillar (insoluble) unmodified Aβ40 and Aβ42 forms and N-terminus truncated and pyroglutamate-modified AβNpE3-40 and AβNpE3-42 forms in postmortem frontal cortex and precuneus samples from 18 DS cases aged 43–63 years and 17 late-onset AD cases aged 62–99 years. Both diagnostic groups had frequent neocortical neuritic plaques, while the DS group had more severe vascular amyloid pathology (cerebral amyloid angiopathy, CAA). Compared to the AD group, the DS group had higher levels of Aβ40 and AβNpE3-40, while the two groups did not differ by Aβ42 and AβNpE3-42 levels. This resulted in lower ratios of Aβ42/Aβ40 and AβNpE3-42/AβNpE3-40 in the DS group compared to the AD group. Correlations of Aβ42/Aβ40 and AβNpE3-42/AβNpE3-40 ratios with CAA severity were strong in DS cases and weak in AD cases. Pyroglutamate-modified Aβ levels were lower than unmodified Aβ levels in both diagnostic groups, but within group proportions of both pyroglutamate-modified Aβ forms relative to both unmodified Aβ forms were lower in the DS group but not in the AD group. The two diagnostic groups did not differ by 3H-PiB binding levels. These results demonstrate that compared to late-onset AD cases, adult DS individuals with similar severity of neocortical neuritic plaques and greater CAA pathology have a preponderance of both pyroglutamate-modified AβNpE3-40 and unmodified Aβ40 forms. Despite the distinct molecular profile of Aβ forms and greater vascular amyloidosis in DS cases, cortical 3H-PiB binding does not distinguish between diagnostic groups that are at an advanced level of amyloid plaque pathology. This underscores the need for the development of CAA-selective PET radiopharmaceuticals to detect and track the progression of cerebral vascular amyloid deposits in relation to Aβ plaques in individuals with DS.
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Affiliation(s)
- Violetta N Pivtoraiko
- Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, Pittsburgh, PA, United States.,Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Tamara Racic
- Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Eric E Abrahamson
- Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, Pittsburgh, PA, United States.,Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Victor L Villemagne
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Benjamin L Handen
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Ira T Lott
- Department of Neurology, UC Irvine School of Medicine, Orange, CA, United States
| | - Elizabeth Head
- Department of Pathology and Laboratory Medicine, UC Irvine School of Medicine, Orange, CA, United States
| | - Milos D Ikonomovic
- Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, Pittsburgh, PA, United States.,Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States.,Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
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3
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Montoliu-Gaya L, Strydom A, Blennow K, Zetterberg H, Ashton NJ. Blood Biomarkers for Alzheimer's Disease in Down Syndrome. J Clin Med 2021; 10:3639. [PMID: 34441934 PMCID: PMC8397053 DOI: 10.3390/jcm10163639] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/09/2021] [Accepted: 08/12/2021] [Indexed: 12/15/2022] Open
Abstract
Epidemiological evidence suggests that by the age of 40 years, all individuals with Down syndrome (DS) have Alzheimer's disease (AD) neuropathology. Clinical diagnosis of dementia by cognitive assessment is complex in these patients due to the pre-existing and varying intellectual disability, which may mask subtle declines in cognitive functioning. Cerebrospinal fluid (CSF) and positron emission tomography (PET) biomarkers, although accurate, are expensive, invasive, and particularly challenging in such a vulnerable population. The advances in ultra-sensitive detection methods have highlighted blood biomarkers as a valuable and realistic tool for AD diagnosis. Studies with DS patients have proven the potential blood-based biomarkers for sporadic AD (amyloid-β, tau, phosphorylated tau, and neurofilament light chain) to be useful in this population. In addition, biomarkers related to other pathologies that could aggravate dementia progression-such as inflammatory dysregulation, energetic imbalance, or oxidative stress-have been explored. This review serves to provide a brief overview of the main findings from the limited neuroimaging and CSF studies, outline the current state of blood biomarkers to diagnose AD in patients with DS, discuss possible past limitations of the research, and suggest considerations for developing and validating blood-based biomarkers in the future.
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Affiliation(s)
- Laia Montoliu-Gaya
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience & Physiology, The Sahlgrenska Academy at the University of Gothenburg, 431 41 Mölndal, Sweden; (K.B.); (H.Z.); (N.J.A.)
| | - Andre Strydom
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London WC2R 2LS, UK;
- South London and Maudsley NHS Foundation Trust, London SE5 8AZ, UK
- London Down Syndrome Consortium (LonDowns), London, UK
| | - Kaj Blennow
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience & Physiology, The Sahlgrenska Academy at the University of Gothenburg, 431 41 Mölndal, Sweden; (K.B.); (H.Z.); (N.J.A.)
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, 413 45 Mölndal, Sweden
| | - Henrik Zetterberg
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience & Physiology, The Sahlgrenska Academy at the University of Gothenburg, 431 41 Mölndal, Sweden; (K.B.); (H.Z.); (N.J.A.)
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, 413 45 Mölndal, Sweden
- Department of Neurodegenerative Disease, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
- UK Dementia Research Institute, University College London, London WC1E 6BT, UK
- Hong Kong Center for Neurodegenerative Diseases, Hong Kong, China
| | - Nicholas James Ashton
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience & Physiology, The Sahlgrenska Academy at the University of Gothenburg, 431 41 Mölndal, Sweden; (K.B.); (H.Z.); (N.J.A.)
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Gothenburg, Sweden
- Department of Old Age Psychiatry, Maurice Wohl Clinical Neuroscience Institute, King’s College London, London SE5 9RT, UK
- NIHR Biomedical Research Centre for Mental Health, Biomedical Research Unit for Dementia at South London, Maudsley NHS Foundation, London SE5 8AF, UK
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4
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Koenig KA, Bekris LM, Ruedrich S, Weber GE, Khrestian M, Oh SH, Kim S, Wang ZI, Leverenz JB. High-resolution functional connectivity of the default mode network in young adults with down syndrome. Brain Imaging Behav 2021; 15:2051-2060. [PMID: 33070299 PMCID: PMC8053201 DOI: 10.1007/s11682-020-00399-z] [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] [Accepted: 09/07/2020] [Indexed: 10/23/2022]
Abstract
Studies of resting-state functional connectivity MRI in Alzheimer's disease suggest that disease stage plays a role in functional changes of the default mode network. Individuals with the genetic disorder Down syndrome show an increased incidence of early-onset Alzheimer's-type dementia, along with early and nearly universal neuropathologic changes of Alzheimer's disease. The present study examined high-resolution functional connectivity of the default mode network in 11 young adults with Down syndrome that showed no measurable symptoms of dementia and 11 age- and sex-matched neurotypical controls. We focused on within-network connectivity of the default mode network, measured from both anterior and posterior aspects of the cingulate cortex. Sixty-eight percent of connections to the posterior cingulate and 26% to the anterior cingulate showed reduced strength in the group with Down syndrome (p < 0.01). The Down syndrome group showed increased connectivity strength from the anterior cingulate to the bilateral inferior frontal gyri and right putamen (p < 0.005). In an exploratory analysis, connectivity in the group with Down syndrome showed regional relationships to plasma measures of inflammatory markers and t-tau. In non-demented adults with Down syndrome, functional connectivity within the default mode network may be analogous to changes reported in preclinical Alzheimer's disease, and warrants further investigation as a measure of dementia risk.
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Affiliation(s)
- Katherine A Koenig
- Imaging Sciences, Imaging Institute, Cleveland Clinic, 9500 Euclid Ave / U15, Cleveland, OH, 44195, USA.
| | - Lynn M Bekris
- Genomic Medicine Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Stephen Ruedrich
- Department of Psychiatry, University Hospitals, Cleveland, OH, USA
| | - Grace E Weber
- Genomic Medicine Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Maria Khrestian
- Genomic Medicine Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Se-Hong Oh
- Imaging Sciences, Imaging Institute, Cleveland Clinic, 9500 Euclid Ave / U15, Cleveland, OH, 44195, USA
- Department of Biomedical Engineering, Hankuk University of Foreign Studies, Yongin, Republic of Korea
| | - Sanghoon Kim
- Imaging Sciences, Imaging Institute, Cleveland Clinic, 9500 Euclid Ave / U15, Cleveland, OH, 44195, USA
| | - Z Irene Wang
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA
| | - James B Leverenz
- Lou Ruvo Center for Brain Health, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA
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5
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Elevated soluble amyloid beta protofibrils in Down syndrome and Alzheimer's disease. Mol Cell Neurosci 2021; 114:103641. [PMID: 34091073 DOI: 10.1016/j.mcn.2021.103641] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 05/27/2021] [Accepted: 05/31/2021] [Indexed: 01/31/2023] Open
Abstract
Down syndrome (DS) is caused by trisomy of chromosome 21, which leads to a propensity to develop amyloid β (Aβ) brain pathology in early adulthood followed later by cognitive and behavioral deterioration. Characterization of the Aβ pathology is important to better understand the clinical deterioration of DS individuals and to identify interventive strategies. Brain samples from people with DS and Alzheimer's disease (AD), as well as non-demented controls (NDC), were analyzed with respect to different Aβ species. Immunohistochemical staining using antibodies towards Aβ was also performed. Elevated levels of soluble Aβ protofibrils and insoluble Aβx-40 and Aβx-42 in formic acid brain extracts, and elevated immunohistochemical staining of Aβ deposits were demonstrated with the antibody BAN2401 (lecanemab) in DS and AD compared with NDC. These data and the promising data in a large phase 2 CE clinical trial with lecanemab suggest that lecanemab may have the potential to preserve cognitive capacity in DS. Lecanemab is currently in a phase 3 CE clinical trial.
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Rosas HD, Lewis LR, Mercaldo ND, Nasr S, Brickman AM, Siless V, Yassa M, Sathishkumar M, Lott I, Schupf N, Silverman W, Lai F. Altered connectivity of the default mode network in cognitively stable adults with Down syndrome: "Accelerated aging" or a prelude to Alzheimer's disease? ALZHEIMER'S & DEMENTIA (AMSTERDAM, NETHERLANDS) 2021; 13:e12105. [PMID: 34027014 PMCID: PMC8136300 DOI: 10.1002/dad2.12105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 08/18/2020] [Accepted: 08/19/2020] [Indexed: 11/18/2022]
Abstract
INTRODUCTION Most individuals with Down syndrome (DS) have the neuropathological changes of Alzheimer's disease (AD) by age 40 and will have developed dementia by age 60. Alterations of the intrinsic connectivity of the default mode network (DMN) are associated with AD in the neurotypical population. In this study, we sought to determine whether, and how, connectivity between the hubs of the DMN were altered in cognitively stable adults with DS who did not have evidence of either mild cognitive impairment or AD. METHODS Resting state functional MRI scans were collected from 26 healthy adults with DS and 26 healthy age-matched non-DS controls. Nodes comprising the DMN were generated as ROI's (regions of interest) and inter-nodal correlations estimated. RESULTS Analysis of intra-network connectivity of the DMN revealed anterior-posterior DMN dissociation and hyper- and hypo-connectivity, suggesting "accelerated aging" in DS. DISCUSSION Disruption of the DMN may serve as a prelude for AD in DS.
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Affiliation(s)
- H. Diana Rosas
- Department of NeurologyMassachusetts General HospitalHarvard Medical SchoolBostonMassachusettsUSA
- Department of RadiologyAthinoula Martinos CenterMassachusetts General HospitalHarvard Medical SchoolCharlestownMassachusettsUSA
| | - Lydia R. Lewis
- Department of NeurologyMassachusetts General HospitalHarvard Medical SchoolBostonMassachusettsUSA
- Department of RadiologyAthinoula Martinos CenterMassachusetts General HospitalHarvard Medical SchoolCharlestownMassachusettsUSA
| | - Nathaniel D. Mercaldo
- Department of NeurologyMassachusetts General HospitalHarvard Medical SchoolBostonMassachusettsUSA
| | - Shahin Nasr
- Department of RadiologyAthinoula Martinos CenterMassachusetts General HospitalHarvard Medical SchoolCharlestownMassachusettsUSA
| | - Adam M. Brickman
- G. H. Sergievsky Center and Taub Institute for Research on Alzheimer's Disease and the Aging BrainCollege of Physicians and SurgeonsColumbia UniversityNew YorkUSA
- Department of NeurologyColumbia UniversityNew YorkUSA
- Department of EpidemiologyMailman School of Public HealthColumbia UniversityNew YorkUSA
| | - Viviana Siless
- Department of RadiologyAthinoula Martinos CenterMassachusetts General HospitalHarvard Medical SchoolCharlestownMassachusettsUSA
| | - Michael Yassa
- Center for the Neurobiology of Learning and Memory and Department of Neurobiology and BehaviorUniversity of CaliforniaIrvineCaliforniaUSA
| | - Mithra Sathishkumar
- Center for the Neurobiology of Learning and Memory and Department of Neurobiology and BehaviorUniversity of CaliforniaIrvineCaliforniaUSA
| | - Ira Lott
- Department of NeurologyUniversity of CaliforniaIrvineCaliforniaUSA
- Department of PediatricsIrvine Medical CenterUniversity of CaliforniaIrvineCaliforniaUSA
| | - Nicole Schupf
- G. H. Sergievsky Center and Taub Institute for Research on Alzheimer's Disease and the Aging BrainCollege of Physicians and SurgeonsColumbia UniversityNew YorkUSA
- Department of NeurologyColumbia UniversityNew YorkUSA
- Department of NeurologyCollege of Physicians and SurgeonsColumbia UniversityNew YorkUSA
- Department of EpidemiologyMailman School of Public HealthColumbia UniversityNew YorkUSA
| | - Wayne Silverman
- Department of PediatricsIrvine Medical CenterUniversity of CaliforniaIrvineCaliforniaUSA
| | - Florence Lai
- Department of NeurologyMassachusetts General HospitalHarvard Medical SchoolBostonMassachusettsUSA
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7
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Lemoine L, Ledreux A, Mufson EJ, Perez SE, Simic G, Doran E, Lott I, Carroll S, Bharani K, Thomas S, Gilmore A, Hamlett ED, Nordberg A, Granholm AC. Regional binding of tau and amyloid PET tracers in Down syndrome autopsy brain tissue. Mol Neurodegener 2020; 15:68. [PMID: 33222700 PMCID: PMC7682014 DOI: 10.1186/s13024-020-00414-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 10/17/2020] [Indexed: 12/21/2022] Open
Abstract
INTRODUCTION Tau pathology is a major age-related event in Down syndrome with Alzheimer's disease (DS-AD). Although recently, several different Tau PET tracers have been developed as biomarkers for AD, these tracers showed different binding properties in Alzheimer disease and other non-AD tauopathies. They have not been yet investigated in tissue obtained postmortem for DS-AD cases. Here, we evaluated the binding characteristics of two Tau PET tracers (3H-MK6240 and 3H-THK5117) and one amyloid (3H-PIB) ligand in the medial frontal gyrus (MFG) and hippocampus (HIPP) in tissue from adults with DS-AD and DS cases with mild cognitive impairment (MCI) compared to sporadic AD. METHODS Tau and amyloid autoradiography were performed on paraffin-embedded sections. To confirm respective ligand targets, adjacent sections were immunoreacted for phospho-Tau (AT8) and stained for amyloid staining using Amylo-Glo. RESULTS The two Tau tracers showed a significant correlation with each other and with AT8, suggesting that both tracers were binding to Tau deposits. 3H-MK6240 Tau binding correlated with AT8 immunostaining but to a lesser degree than the 3H-THK5117 tracer, suggesting differences in binding sites between the two Tau tracers. 3H-THK5117, 3H-MK6240 and 3H-PIB displayed dense laminar binding in the HIPP and MFG in adult DS brains. A regional difference in Tau binding between adult DS and AD was observed suggesting differential regional Tau deposition in adult DS compared to AD, with higher THK binding density in the MFG in adult with DS compared to AD. No significant correlation was found between 3H-PIB and Amylo-Glo staining in adult DS brains suggesting that the amyloid PIB tracer binds to additional sites. CONCLUSIONS This study provides new insights into the regional binding distribution of a first-generation and a second-generation Tau tracer in limbic and neocortical regions in adults with DS, as well as regional differences in Tau binding in adult with DS vs. those with AD. These findings provide new information about the binding properties of two Tau radiotracers for the detection of Tau pathology in adults with DS in vivo and provide valuable data regarding Tau vs. amyloid binding in adult DS compared to AD.
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Affiliation(s)
- L Lemoine
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden.
| | - A Ledreux
- Knoebel Institute for Healthy Aging (KIHA), University of Denver, Denver, CO, USA
| | - E J Mufson
- Department of Neurobiology and Neurology, Barrow Neurological Institute, Phoenix, AZ, USA
| | - S E Perez
- Department of Neurobiology and Neurology, Barrow Neurological Institute, Phoenix, AZ, USA
| | - G Simic
- Department of Neuroscience, Croatian Institute for Brain Research, University of Zagreb Medical School, Zagreb, Croatia
| | - E Doran
- University of California Irvine, Irvine, CA, USA
| | - I Lott
- University of California Irvine, Irvine, CA, USA
| | - S Carroll
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, USA
| | - K Bharani
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, USA
| | - S Thomas
- Knoebel Institute for Healthy Aging (KIHA), University of Denver, Denver, CO, USA
| | - A Gilmore
- Knoebel Institute for Healthy Aging (KIHA), University of Denver, Denver, CO, USA
| | - E D Hamlett
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, USA
| | - A Nordberg
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden.,Theme Aging, Karolinska University Hospital, Stockholm, Sweden
| | - A C Granholm
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden.,Knoebel Institute for Healthy Aging (KIHA), University of Denver, Denver, CO, USA
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8
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Forloni G. Alzheimer's disease: from basic science to precision medicine approach. BMJ Neurol Open 2020; 2:e000079. [PMID: 33681801 PMCID: PMC7903168 DOI: 10.1136/bmjno-2020-000079] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 08/24/2020] [Accepted: 10/16/2020] [Indexed: 12/14/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common form of dementia in the elderly. Together with cerebral amyloid accumulation, several factors contribute to AD pathology including vascular alterations, systemic inflammation, genetic/epigenetic status and mitochondrial dysfunction. Much is now being devoted to neuroinflammation. However, anti-inflammatory drugs as numerous other therapies, mainly targeted on β-amyloid, have failed to show efficacious effects in AD. Timing, proper selection of patients, and the need for a multitarget approach appear to be the main weak points of current therapeutic efforts. The efficacy of a treatment could be better evaluate if efficient biomarkers are available. We propose here the application of precision medicine principles in AD to simultaneously verify the efficacy of a treatment and the reliability of specific biomarkers according to individually tailored biomarker-guided targeted therapies. People at risk of developing AD or in the very early phase of the disease should be stratified according to: (1) neuropsychological tests; (2) apolipoprotein E (ApoE) genotyping; (3) biochemical analysis of plasma and cerebrospinal fluid (CSF); (4) MRI and positron emission tomography and (5) assessment of their inflammatory profile by an integration of various genetic and biochemical parameters in plasma, CSF and an analysis of microbiota composition. The selected population should be treated with antiamyloidogenic and anti-inflammatory drugs in randomised, longitudinal, placebo-controlled studies using ad hoc profiles (eg, vascular profile, mitochondrial profile, etc…) If these criteria are adopted widely and the results shared, it may be possible to rapidly develop innovative and personalised drug treatment protocols with more realistic chances of being efficacious.
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Affiliation(s)
- Gianluigi Forloni
- Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri, Milano, Lombardia, Italy
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Keator DB, Doran E, Taylor L, Phelan MJ, Hom C, Tseung K, van Erp TGM, Potkin SG, Brickman AM, Rosas DH, Yassa MA, Silverman W, Lott IT. Brain amyloid and the transition to dementia in Down syndrome. ALZHEIMER'S & DEMENTIA (AMSTERDAM, NETHERLANDS) 2020; 12:e12126. [PMID: 33204814 PMCID: PMC7656170 DOI: 10.1002/dad2.12126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 09/30/2020] [Accepted: 10/01/2020] [Indexed: 11/15/2022]
Abstract
INTRODUCTION Down syndrome (DS) is associated with elevated risk for Alzheimer's disease (AD) due to amyloid beta (Aβ) lifelong accumulation. We hypothesized that the spatial distribution of brain Aβ predicts future dementia conversion in individuals with DS. METHODS We acquired 18F-florbetapir positron emission tomography scans from 19 nondemented individuals with DS at baseline and monitored them for 4 years, with five individuals transitioning to dementia. Machine learning classification using an independent test set determined features on 18F-florbetapir standardized uptake value ratio maps that predicted transition. RESULTS In addition to "AD signature" regions including the inferior parietal cortex, temporal lobes, and the cingulum, we found that Aβ cortical binding in the prefrontal and superior frontal cortices distinguished subjects who transitioned to dementia. Classification did well in predicting transitioners. DISCUSSION Our study suggests that specific regional profiles of brain amyloid in older adults with DS may predict cognitive decline and are informative in evaluating the risk for dementia.
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Affiliation(s)
- David B. Keator
- Department of Psychiatry and Human BehaviorUniversity of California, IrvineIrvineCaliforniaUSA
| | - Eric Doran
- Department of PediatricsIrvine Medical CenterUniversity of CaliforniaOrangeCaliforniaUSA
| | - Lisa Taylor
- Department of Psychiatry and Human BehaviorUniversity of California, IrvineIrvineCaliforniaUSA
| | - Michael J. Phelan
- Department of StatisticsUniversity of California, IrvineIrvineCaliforniaUSA
| | - Christy Hom
- Department of Psychiatry and Human BehaviorUniversity of California, IrvineIrvineCaliforniaUSA
| | | | - Theo G. M. van Erp
- Department of Psychiatry and Human BehaviorUniversity of California, IrvineIrvineCaliforniaUSA
- Center for the Neurobiology of Learning and MemoryUniversity of California, IrvineIrvineCaliforniaUSA
| | - Steven G. Potkin
- Department of Psychiatry and Human BehaviorUniversity of California, IrvineIrvineCaliforniaUSA
| | - Adam M. Brickman
- Department of NeurologyCollege of Physicians and SurgeonsColumbia University, New YorkTaub Institute for Research on Alzheimer's Disease and the Aging BrainNew YorkUSA
| | - Diana H. Rosas
- Massachusetts General HospitalHarvard UniversityBostonMassachusettsUSA
| | - Michael A. Yassa
- Department of Psychiatry and Human BehaviorUniversity of California, IrvineIrvineCaliforniaUSA
- Center for the Neurobiology of Learning and MemoryUniversity of California, IrvineIrvineCaliforniaUSA
- Department of Neurobiology and BehaviorUniversity of California, IrvineIrvineCaliforniaUSA
| | - Wayne Silverman
- Department of PediatricsIrvine Medical CenterUniversity of CaliforniaOrangeCaliforniaUSA
| | - Ira T. Lott
- Department of PediatricsIrvine Medical CenterUniversity of CaliforniaOrangeCaliforniaUSA
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10
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Abrahamson EE, Head E, Lott IT, Handen BL, Mufson EJ, Christian BT, Klunk WE, Ikonomovic MD. Neuropathological correlates of amyloid PET imaging in Down syndrome. Dev Neurobiol 2019; 79:750-766. [PMID: 31379087 DOI: 10.1002/dneu.22713] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 07/31/2019] [Accepted: 07/31/2019] [Indexed: 11/07/2022]
Abstract
Down syndrome (DS) results in an overproduction of amyloid-β (Aβ) peptide associated with early onset of Alzheimer's disease (AD). DS cases have Aβ deposits detectable histologically as young as 12-30 years of age, primarily in the form of diffuse plaques, the type of early amyloid pathology also seen at pre-clinical (i.e., pathological aging) and prodromal stages of sporadic late onset AD. In DS subjects aged >40 years, levels of cortical Aβ deposition are similar to those observed in late onset AD and in addition to diffuse plaques involve cored plaques associated with dystrophic neurites (neuritic plaques), which are of neuropathological diagnostic significance in AD. The purpose of this review is to summarize and discuss findings from amyloid PET imaging studies of DS in reference to postmortem amyloid-based neuropathology. PET neuroimaging applied to subjects with DS has the potential to (a) track the natural progression of brain pathology, including the earliest stages of amyloid accumulation, and (b) determine whether amyloid PET biomarkers predict the onset of dementia. In addition, the question that is still incompletely understood and relevant to both applications is the ability of amyloid PET to detect Aβ deposits in their earliest form.
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Affiliation(s)
- Eric E Abrahamson
- Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, Pittsburgh, Pennsylvania.,Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Elizabeth Head
- Department of Pathology and Laboratory Medicine, UC Irvine School of Medicine, Orange, California
| | - Ira T Lott
- Department of Neurology, UC Irvine School of Medicine, Orange, California
| | - Benjamin L Handen
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Elliott J Mufson
- Department of Neurobiology, Barrow Neurological Institute, Phoenix, Arizona
| | - Bradley T Christian
- Departments of Medical Physics and Psychiatry, Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin
| | - William E Klunk
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Milos D Ikonomovic
- Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, Pittsburgh, Pennsylvania.,Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania
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11
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Fonseca LM, Mattar GP, Haddad GG, Gonçalves AS, Miguel ADQC, Guilhoto LM, Zaman S, Holland AJ, Bottino CMDC, Hoexter MQ. Frontal-subcortical behaviors during Alzheimer's disease in individuals with Down syndrome. Neurobiol Aging 2019; 78:186-194. [PMID: 30947114 DOI: 10.1016/j.neurobiolaging.2019.02.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 02/08/2019] [Accepted: 02/28/2019] [Indexed: 11/25/2022]
Abstract
There is evidence that frontal-subcortical circuits play an important role in the initial presentation of dementia in Down syndrome (DS), including changes in behavior, a decline in working memory and executive dysfunction. We evaluated 92 individuals with DS (≥30 years of age), divided into 3 groups by diagnosis-stable cognition, prodromal dementia, and Alzheimer's disease. Each individual was evaluated with an executive protocol developed for people with intellectual disabilities and was rated for behaviors related to frontal lobe dysfunction (disinhibition, executive dysfunction, and apathy) by an informant using the Frontal Systems Behavior Scale. Informant-reported behaviors related to frontal lobe dysfunction were found to correlate negatively with executive function performance. Disinhibition and executive dysfunction were associated with the clinical stage of dementia. The odds of having Alzheimer's disease increased in parallel with increases in the domain and total Frontal Systems Behavior Scale scores (p ≤ 0.5). Disinhibition, executive dysfunction and apathy should be taken into consideration during the clinical evaluation of adults with DS, and future studies should consider the intersection of neuropathology, brain connectivity, and behavior.
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Affiliation(s)
- Luciana Mascarenhas Fonseca
- Old Age Research Group, PROTER, Department and Institute of Psychiatry, University of São Paulo School of Medicine, FMUSP, São Paulo, Brazil; Cambridge Intellectual and Developmental Disabilities Research Group, Department of Psychiatry, University of Cambridge, Cambridge, UK.
| | - Guilherme Prado Mattar
- Old Age Research Group, PROTER, Department and Institute of Psychiatry, University of São Paulo School of Medicine, FMUSP, São Paulo, Brazil
| | - Glenda Guerra Haddad
- Old Age Research Group, PROTER, Department and Institute of Psychiatry, University of São Paulo School of Medicine, FMUSP, São Paulo, Brazil
| | - Aline Souza Gonçalves
- Laboratory of Neuroscience, LIM27, Department and Institute of Psychiatry, University of São Paulo School of Medicine, FMUSP, São Paulo, Brazil
| | | | - Laura Maria Guilhoto
- Association of Parents and Friends of Individuals with Intellectual Disability of São Paulo, São Paulo, Brazil; Department of Neurology and Neurosurgery, Federal University of Sao Paulo, São Paulo, Brazil
| | - Shahid Zaman
- Cambridge Intellectual and Developmental Disabilities Research Group, Department of Psychiatry, University of Cambridge, Cambridge, UK
| | - Anthony J Holland
- Cambridge Intellectual and Developmental Disabilities Research Group, Department of Psychiatry, University of Cambridge, Cambridge, UK
| | - Cassio Machado de Campos Bottino
- Old Age Research Group, PROTER, Department and Institute of Psychiatry, University of São Paulo School of Medicine, FMUSP, São Paulo, Brazil
| | - Marcelo Queiroz Hoexter
- Obsessive-Compulsive Spectrum Disorders Program, PROTOC, Department and Institute of Psychiatry, University of São Paulo School of Medicine, FMUSP, São Paulo, Brazil
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12
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Perez SE, Miguel JC, He B, Malek-Ahmadi M, Abrahamson EE, Ikonomovic MD, Lott I, Doran E, Alldred MJ, Ginsberg SD, Mufson EJ. Frontal cortex and striatal cellular and molecular pathobiology in individuals with Down syndrome with and without dementia. Acta Neuropathol 2019; 137:413-436. [PMID: 30734106 PMCID: PMC6541490 DOI: 10.1007/s00401-019-01965-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 01/18/2019] [Accepted: 01/22/2019] [Indexed: 02/06/2023]
Abstract
Although, by age 40, individuals with Down syndrome (DS) develop amyloid-β (Aβ) plaques and tau-containing neurofibrillary tangles (NFTs) linked to cognitive impairment in Alzheimer's disease (AD), not all people with DS develop dementia. Whether Aβ plaques and NFTs are associated with individuals with DS with (DSD +) and without dementia (DSD -) is under-investigated. Here, we applied quantitative immunocytochemistry and fluorescent procedures to characterize NFT pathology using antibodies specific for tau phosphorylation (pS422, AT8), truncation (TauC3, MN423), and conformational (Alz50, MC1) epitopes, as well as Aβ and its precursor protein (APP) to frontal cortex (FC) and striatal tissue from DSD + to DSD - cases. Expression profiling of single pS422 labeled FC layer V and VI neurons was also determined using laser capture microdissection and custom-designed microarray analysis. Analysis revealed that cortical and striatal Aβ plaque burdens were similar in DSD + and DSD - cases. In both groups, most FC plaques were neuritic, while striatal plaques were diffuse. By contrast, FC AT8-positive NFTs and neuropil thread densities were significantly greater in DSD + compared to DSD -, while striatal NFT densities were similar between groups. FC pS422-positive and TauC3 NFT densities were significantly greater than Alz50-labeled NFTs in DSD + , but not DSD - cases. Putaminal, but not caudate pS422-positive NFT density, was significantly greater than TauC3-positive NFTs. In the FC, AT8 + pS422 + Alz50, TauC3 + pS422 + Alz50, pS422 + Alz50, and TauC3 + pS422 positive NFTs were more frequent in DSD + compared to DSD- cases. Single gene-array profiling of FC pS422 positive neurons revealed downregulation of 63 of a total of 864 transcripts related to Aβ/tau biology, glutamatergic, cholinergic, and monoaminergic metabolism, intracellular signaling, cell homeostasis, and cell death in DSD + compared DSD - cases. These observations suggest that abnormal tau aggregation plays a critical role in the development of dementia in DS.
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Affiliation(s)
- Sylvia E Perez
- Department of Neurobiology and Neurology, Barrow Neurological Institute, 350 W. Thomas St, Phoenix, AZ, 85013, USA
- School of Life Sciences, College of Liberal Arts and Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - Jennifer C Miguel
- Department of Neurobiology and Neurology, Barrow Neurological Institute, 350 W. Thomas St, Phoenix, AZ, 85013, USA
| | - Bin He
- Department of Neurobiology and Neurology, Barrow Neurological Institute, 350 W. Thomas St, Phoenix, AZ, 85013, USA
| | | | - Eric E Abrahamson
- Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, Pittsburgh, PA, 15213, USA
- Departments of Neurology and Psychiatry, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Milos D Ikonomovic
- Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, Pittsburgh, PA, 15213, USA
- Departments of Neurology and Psychiatry, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Ira Lott
- Departments of Pediatrics and Neurology, University of California, Irvine, CA, 92697, USA
| | - Eric Doran
- Departments of Pediatrics and Neurology, University of California, Irvine, CA, 92697, USA
| | - Melissa J Alldred
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY, 10962, USA
- Departments of Psychiatry, NYU Neuroscience Institute, NYU Langone Medical Center, New York, NY, 10021, USA
| | - Stephen D Ginsberg
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY, 10962, USA
- Departments of Psychiatry, NYU Neuroscience Institute, NYU Langone Medical Center, New York, NY, 10021, USA
- Departments of Neuroscience and Physiology, The NYU Neuroscience Institute, NYU Langone Medical Center, New York, NY, 10021, USA
| | - Elliott J Mufson
- Department of Neurobiology and Neurology, Barrow Neurological Institute, 350 W. Thomas St, Phoenix, AZ, 85013, USA.
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13
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Prakash SK, San Roman AK, Crenshaw M, Flink B, Earle K, Los E, Bonnard Å, Lin AE. "Donating our bodies to science": A discussion about autopsy and organ donation in Turner syndrome. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2019; 181:36-42. [PMID: 30633443 DOI: 10.1002/ajmg.c.31671] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 12/17/2018] [Accepted: 12/18/2018] [Indexed: 12/14/2022]
Abstract
At the Third Turner Resource Network Symposium, a working group presented the results of collaborative discussions about the importance of autopsy in Turner syndrome (TS). Considerable gaps in understanding the causes of death in TS can only be closed by more frequent death investigations and autopsies. The presentation included an overview of autopsy methods, strategies for utilizing autopsy, and biobanking to address research questions about TS, and the role of palliative care in the context of autopsy. This review highlights strategies to promote autopsy and tissue donation, culminating with an action plan to increase autopsy rates in the TS community.
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Affiliation(s)
- Siddharth K Prakash
- Department of Internal Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas
| | | | - Melissa Crenshaw
- Division of Genetics, Johns Hopkins All Children's Hospital, St. Petersburg, Florida
| | - Barbara Flink
- Turner Syndrome Society of the United States, Houston, Texas
| | - Kimberly Earle
- Department of Pediatrics, Division of Neonatology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas.,Division of Geriatrics, Hospice and Palliative Medicine, University of Texas Health Science Center at Houston, Houston, Texas
| | - Evan Los
- Department of Pediatrics, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee
| | - Åsa Bonnard
- Department of Otorhinolaryngology, Karolinska University Hospital, Stockholm, Sweden
| | - Angela E Lin
- Genetics Unit, MassGeneral Hospital for Children, Boston, Massachusetts
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14
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Head E, Powell DK, Schmitt FA. Metabolic and Vascular Imaging Biomarkers in Down Syndrome Provide Unique Insights Into Brain Aging and Alzheimer Disease Pathogenesis. Front Aging Neurosci 2018; 10:191. [PMID: 29977201 PMCID: PMC6021507 DOI: 10.3389/fnagi.2018.00191] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 06/06/2018] [Indexed: 12/26/2022] Open
Abstract
People with Down syndrome (DS) are at high risk for developing Alzheimer disease (AD). Neuropathology consistent with AD is present by 40 years of age and dementia may develop up to a decade later. In this review, we describe metabolic and vascular neuroimaging studies in DS that suggest these functional changes are a key feature of aging, linked to cognitive decline and AD in this vulnerable cohort. FDG-PET imaging in DS suggests systematic reductions in glucose metabolism in posterior cingulate and parietotemporal cortex. Magentic resonance spectroscopy studies show consistent decreases in neuronal health and increased myoinositol, suggesting inflammation. There are few vascular imaging studies in DS suggesting a gap in our knowledge. Future studies would benefit from longitudinal measures and combining various imaging approaches to identify early signs of dementia in DS that may be amenable to intervention.
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Affiliation(s)
- Elizabeth Head
- Department of Pharmacology & Nutritional Sciences, Sanders Brown Center on Aging, University of Kentucky, Lexington, KY, United States
| | - David K Powell
- Magnetic Resonance Imaging and Spectroscopy Center, Sanders Brown Center on Aging, University of Kentucky, Lexington, KY, United States
| | - Frederick A Schmitt
- Department of Neurology, Sanders Brown Center on Aging, University of Kentucky, Lexington, KY, United States
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15
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Head E, Helman AM, Powell D, Schmitt FA. Down syndrome, beta-amyloid and neuroimaging. Free Radic Biol Med 2018; 114:102-109. [PMID: 28935420 PMCID: PMC5748259 DOI: 10.1016/j.freeradbiomed.2017.09.013] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 09/12/2017] [Accepted: 09/14/2017] [Indexed: 12/20/2022]
Abstract
This review focuses on the role of Aβ in AD pathogenesis in Down syndrome and current approaches for imaging Aβ in vivo. We will describe how Aβ deposits with age, the posttranslational modifications that can occur, and detection in biofluids. Three unique case studies describing partial trisomy 21 cases without APP triplication, and the occurrences of low level mosaic trisomy 21 in an early onset AD patient are presented. Brain imaging for Aβ includes those by positron emission tomography and ligands (Pittsburgh Compound B, Florbetapir, and FDDNP) that bind Aβ have been published and are summarized here. In combination, we have learned a great deal about Aβ in DS in terms of characterizing age of onset of this pathology and it is exciting to note that there is a clinical trial in DS targeting Aβ that may lead to clinical benefits.
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Affiliation(s)
- Elizabeth Head
- University of Kentucky, Sanders-Brown Center on Aging, 800 South Limestone Street, Lexington, KY 40536, United States; University of Kentucky, Department of Pharmacology & Nutritional Sciences, Lexington, KY 40536, United States.
| | - Alex M Helman
- University of Kentucky, Sanders-Brown Center on Aging, 800 South Limestone Street, Lexington, KY 40536, United States; University of Kentucky, Department of Pharmacology & Nutritional Sciences, Lexington, KY 40536, United States; University of Kentucky, Magnetic Resonance Imaging and Spectroscopy Center, Lexington, KY 40536, United States; University of Kentucky, Department of Neurology, Lexington, KY 40536, United States
| | - David Powell
- University of Kentucky, Magnetic Resonance Imaging and Spectroscopy Center, Lexington, KY 40536, United States
| | - Frederick A Schmitt
- University of Kentucky, Sanders-Brown Center on Aging, 800 South Limestone Street, Lexington, KY 40536, United States; University of Kentucky, Department of Neurology, Lexington, KY 40536, United States
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16
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Neale N, Padilla C, Fonseca LM, Holland T, Zaman S. Neuroimaging and other modalities to assess Alzheimer's disease in Down syndrome. NEUROIMAGE-CLINICAL 2017; 17:263-271. [PMID: 29159043 PMCID: PMC5683343 DOI: 10.1016/j.nicl.2017.10.022] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 10/18/2017] [Accepted: 10/23/2017] [Indexed: 12/29/2022]
Abstract
People with Down syndrome (DS) develop Alzheimer's disease (AD) at higher rates and a younger age of onset compared to the general population. As the average lifespan of people with DS is increasing, AD is becoming an important health concern in this group. Neuroimaging is becoming an increasingly useful tool in understanding the pathogenesis of dementia development in relation to clinical symptoms. Furthermore, neuroimaging has the potential to play a role in AD diagnosis and monitoring of therapeutics. This review describes major recent findings from in vivo neuroimaging studies analysing DS and AD via ligand-based positron emission tomography (PET), [18F] fluorodeoxyglucose (FDG)-PET, structural magnetic resonance imaging (sMRI), and diffusion tensor imaging (DTI). Electroencephalography (EEG) and retinal imaging are also discussed as emerging modalities. The review is organized by neuroimaging method and assesses the relationship between cognitive decline and neuroimaging changes. We find that amyloid accumulation seen on PET occurs prior to dementia onset, possibly as a precursor to the atrophy and white matter changes seen in MRI studies. Future PET studies relating tau distribution to clinical symptoms will provide further insight into the role this protein plays in dementia development. Brain activity changes demonstrated by EEG and metabolic changes seen via FDG-PET may also follow predictable patterns that can help track dementia progression. Finally, newer approaches such as retinal imaging will hopefully overcome some of the limitations of neuroimaging and allow for detection of dementia at an earlier stage. We review recent neuroimaging findings in the field of Down syndrome and Alzheimer's disease. Review is organized by neuroimaging methodology. Correlation between cognitive decline and imaging findings is considered. Neuroimaging is a useful tool for studying and monitoring Alzheimer's disease in the Down syndrome population.
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Key Words
- AD, Alzheimer's disease
- APP, amyloid precursor protein
- Aβ, amyloid beta
- Biomarkers
- DS, Down syndrome
- DTI, diffusion tensor imaging
- Dementia
- Diffusion tensor imaging (DTI)
- EEG, electroencephalography
- Electroencephalography (EEG)
- FDG, fluordexoyglucose
- Magnetic resonance imaging (MRI)
- NFT, neurofibrillary tangles
- PET, positron emission tomography
- Positron emission tomography (PET)
- sMRI, structural magnetic resonance imaging
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Affiliation(s)
- Natalie Neale
- Perelman School of Medicine at the University of Pennsylvania, 3400 Civic Center Boulevard, Philadelphia, PA 19104, United States.
| | - Concepcion Padilla
- Cambridge Intellectual and Developmental Disabilities Research Group, Department of Psychiatry, University of Cambridge, 18B Trumpington Road, Cambridge, England CB2 8AH, United Kingdom
| | - Luciana Mascarenhas Fonseca
- Cambridge Intellectual and Developmental Disabilities Research Group, Department of Psychiatry, University of Cambridge, 18B Trumpington Road, Cambridge, England CB2 8AH, United Kingdom; Old Age Research Group (PROTER), Department of Psychiatry, University of Sao Paulo, Rua da Reitoria, 374, Cidade Universitaria, Sao Paulo 05508-010, Brazil
| | - Tony Holland
- Cambridge Intellectual and Developmental Disabilities Research Group, Department of Psychiatry, University of Cambridge, 18B Trumpington Road, Cambridge, England CB2 8AH, United Kingdom
| | - Shahid Zaman
- Cambridge Intellectual and Developmental Disabilities Research Group, Department of Psychiatry, University of Cambridge, 18B Trumpington Road, Cambridge, England CB2 8AH, United Kingdom
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