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Zammit MD, Betthauser TJ, McVea AK, Laymon CM, Tudorascu DL, Johnson SC, Hartley SL, Converse AK, Minhas DS, Zaman SH, Ances BM, Stone CK, Mathis CA, Cohen AD, Klunk WE, Handen BL, Christian BT. Characterizing the emergence of amyloid and tau burden in Down syndrome. Alzheimers Dement 2024; 20:388-398. [PMID: 37641577 PMCID: PMC10843570 DOI: 10.1002/alz.13444] [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: 05/17/2023] [Revised: 07/14/2023] [Accepted: 07/23/2023] [Indexed: 08/31/2023]
Abstract
INTRODUCTION Almost all individuals with Down syndrome (DS) will develop neuropathological features of Alzheimer's disease (AD). Understanding AD biomarker trajectories is necessary for DS-specific clinical interventions and interpretation of drug-related changes in the disease trajectory. METHODS A total of 177 adults with DS from the Alzheimer's Biomarker Consortium-Down Syndrome (ABC-DS) underwent positron emission tomography (PET) and MR imaging. Amyloid-beta (Aβ) trajectories were modeled to provide individual-level estimates of Aβ-positive (A+) chronicity, which were compared against longitudinal tau change. RESULTS Elevated tau was observed in all NFT regions following A+ and longitudinal tau increased with respect to A+ chronicity. Tau increases in NFT regions I-III was observed 0-2.5 years following A+. Nearly all A+ individuals had tau increases in the medial temporal lobe. DISCUSSION These findings highlight the rapid accumulation of amyloid and early onset of tau relative to amyloid in DS and provide a strategy for temporally characterizing AD neuropathology progression that is specific to the DS population and independent of chronological age. HIGHLIGHTS Longitudinal amyloid trajectories reveal rapid Aβ accumulation in Down syndrome NFT stage tau was strongly associated with A+ chronicity Early longitudinal tau increases were observed 2.5-5 years after reaching A.
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Affiliation(s)
| | - Tobey J. Betthauser
- University of Wisconsin‐Madison Alzheimer's Disease Research CenterMadisonWisconsinUSA
- Department of MedicineUniversity of Wisconsin‐MadisonMadisonWisconsinUSA
| | - Andrew K. McVea
- University of Wisconsin‐Madison Waisman CenterMadisonWisconsinUSA
| | - Charles M. Laymon
- Department of RadiologyUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Dana L. Tudorascu
- Department of PsychiatryUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Sterling C. Johnson
- University of Wisconsin‐Madison Alzheimer's Disease Research CenterMadisonWisconsinUSA
- Department of MedicineUniversity of Wisconsin‐MadisonMadisonWisconsinUSA
| | - Sigan L. Hartley
- University of Wisconsin‐Madison Waisman CenterMadisonWisconsinUSA
| | | | - Davneet S. Minhas
- Department of RadiologyUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Shahid H. Zaman
- Cambridge Intellectual Disability Research GroupUniversity of CambridgeCambridgeUK
| | - Beau M. Ances
- Department of NeurologyWashington University in St. LouisSt. LouisMissouriUSA
| | - Charles K. Stone
- Department of MedicineUniversity of Wisconsin‐MadisonMadisonWisconsinUSA
| | - Chester A. Mathis
- Department of PsychiatryUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Annie D. Cohen
- Department of PsychiatryUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - William E. Klunk
- Department of PsychiatryUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Benjamin L. Handen
- Department of PsychiatryUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Bradley T. Christian
- University of Wisconsin‐Madison Waisman CenterMadisonWisconsinUSA
- Department of Medical PhysicsUniversity of Wisconsin‐MadisonMadisonWisconsinUSA
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Fortea J, Zaman SH, Hartley S, Rafii MS, Head E, Carmona-Iragui M. Alzheimer's disease associated with Down syndrome: a genetic form of dementia. Lancet Neurol 2021; 20:930-942. [PMID: 34687637 PMCID: PMC9387748 DOI: 10.1016/s1474-4422(21)00245-3] [Citation(s) in RCA: 85] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 07/14/2021] [Accepted: 07/21/2021] [Indexed: 02/03/2023]
Abstract
Adults with Down syndrome develop the neuropathological hallmarks of Alzheimer's disease and are at very high risk of developing early-onset dementia, which is now the leading cause of death in this population. Diagnosis of dementia remains a clinical challenge because of the lack of validated diagnostic criteria in this population, and because symptoms are overshadowed by the intellectual disability associated with Down syndrome. In people with Down syndrome, fluid and imaging biomarkers have shown good diagnostic performances and a strikingly similar temporality of changes with respect to sporadic and autosomal dominant Alzheimer's disease. Most importantly, there are no treatments to prevent Alzheimer's disease, even though adults with Down syndrome could be an optimal population in whom to conduct Alzheimer's disease prevention trials. Unprecedented research activity in Down syndrome is rapidly changing this bleak scenario that will translate into disease-modifying therapies that could benefit other populations.
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Affiliation(s)
- Juan Fortea
- Sant Pau Memory Unit, Department of Neurology, Hospital de la Santa Creu y Sant Pau, Biomedical Research Institute Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain; Barcelona Down Medical Center, Fundació Catalana Síndrome de Down, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas. CIBERNED, Madrid, Spain.
| | - Shahid H Zaman
- Department of Psychiatry, School of Clinical Medicine, University of Cambridge, Cambridge, UK.,Cambridgeshire & Peterborough NHS Foundation Trust, Cambridge, UK
| | - Sigan Hartley
- Waisman Center, University of Wisconsin-Madison. Madison, USA
| | - Michael S Rafii
- Alzheimer’s Therapeutic Research Institute (ATRI), Keck School of Medicine, University of Southern California. San Diego, USA
| | - Elizabeth Head
- Department of Pathology and Laboratory Medicine, University of California. Irvine, USA
| | - Maria Carmona-Iragui
- Sant Pau Memory Unit, Neurology Department, Hospital de la Santa Creu i Sant Pau - Biomedical Research Institute Sant Pau- Universitat Autònoma de Barcelona, Barcelona, Spain.,Barcelona Down Medical Center, Fundació Catalana Síndrome de Down, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas. CIBERNED, Madrid, Spain
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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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Martinez JL, Zammit MD, West NR, Christian BT, Bhattacharyya A. Basal Forebrain Cholinergic Neurons: Linking Down Syndrome and Alzheimer's Disease. Front Aging Neurosci 2021; 13:703876. [PMID: 34322015 PMCID: PMC8311593 DOI: 10.3389/fnagi.2021.703876] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/17/2021] [Indexed: 12/31/2022] Open
Abstract
Down syndrome (DS, trisomy 21) is characterized by intellectual impairment at birth and Alzheimer's disease (AD) pathology in middle age. As individuals with DS age, their cognitive functions decline as they develop AD pathology. The susceptibility to degeneration of a subset of neurons, known as basal forebrain cholinergic neurons (BFCNs), in DS and AD is a critical link between cognitive impairment and neurodegeneration in both disorders. BFCNs are the primary source of cholinergic innervation to the cerebral cortex and hippocampus, as well as the amygdala. They play a critical role in the processing of information related to cognitive function and are directly engaged in regulating circuits of attention and memory throughout the lifespan. Given the importance of BFCNs in attention and memory, it is not surprising that these neurons contribute to dysfunctional neuronal circuitry in DS and are vulnerable in adults with DS and AD, where their degeneration leads to memory loss and disturbance in language. BFCNs are thus a relevant cell target for therapeutics for both DS and AD but, despite some success, efforts in this area have waned. There are gaps in our knowledge of BFCN vulnerability that preclude our ability to effectively design interventions. Here, we review the role of BFCN function and degeneration in AD and DS and identify under-studied aspects of BFCN biology. The current gaps in BFCN relevant imaging studies, therapeutics, and human models limit our insight into the mechanistic vulnerability of BFCNs in individuals with DS and AD.
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Affiliation(s)
- Jose L. Martinez
- Cellular and Molecular Biology Graduate Program, University of Wisconsin, Madison, WI, United States
- Waisman Center, University of Wisconsin, Madison, WI, United States
| | - Matthew D. Zammit
- Waisman Center, University of Wisconsin, Madison, WI, United States
- Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin, Madison, WI, United States
| | - Nicole R. West
- Cellular and Molecular Biology Graduate Program, University of Wisconsin, Madison, WI, United States
- Waisman Center, University of Wisconsin, Madison, WI, United States
| | - Bradley T. Christian
- Waisman Center, University of Wisconsin, Madison, WI, United States
- Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin, Madison, WI, United States
- Department of Psychiatry, School of Medicine and Public Health, University of Wisconsin, Madison, WI, United States
| | - Anita Bhattacharyya
- Waisman Center, University of Wisconsin, Madison, WI, United States
- Department of Cellular and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin, Madison, WI, United States
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Zammit MD, Tudorascu DL, Laymon CM, Hartley SL, Ellison PA, Zaman SH, Ances BM, Johnson SC, Stone CK, Sabbagh MN, Mathis CA, Klunk WE, Cohen AD, Handen BL, Christian BT. Neurofibrillary tau depositions emerge with subthreshold cerebral beta-amyloidosis in down syndrome. NEUROIMAGE-CLINICAL 2021; 31:102740. [PMID: 34182407 PMCID: PMC8252122 DOI: 10.1016/j.nicl.2021.102740] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/20/2021] [Accepted: 06/21/2021] [Indexed: 01/04/2023]
Abstract
Neurofibrillary tau deposition in Down syndrome follows the Braak staging pathology. Neurofibrillary tau emerges in individuals with very low amyloid burden. There is a short latency between the onset of amyloid and tau in Down syndrome. Elevated tau was observed in Braak stages I-II with very low amyloid burden, and in stages III-VI with greater amyloid burden.
Introduction Adults with Down syndrome are genetically predisposed to develop Alzheimer’s disease and accumulate beta-amyloid plaques (Aβ) early in life. While Aβ has been heavily studied in Down syndrome, its relationship with neurofibrillary tau is less understood. The aim of this study was to evaluate neurofibrillary tau deposition in individuals with Down syndrome with varying levels of Aβ burden. Methods A total of 161 adults with Down syndrome (mean age = 39.2 (8.50) years) and 40 healthy, non-Down syndrome sibling controls (43.2 (12.6) years) underwent T1w-MRI, [C-11]PiB and [F-18]AV-1451 PET scans. PET images were converted to units of standardized uptake value ratios (SUVrs). Aβ burden was calculated using the amyloid load metric (AβL); a measure of global Aβ burden that improves quantification from SUVrs by suppressing the nonspecific binding signal component and computing the specific Aβ signal from all Aβ-carrying voxels from the image. Regional tau was assessed using control-standardized AV-1451 SUVr. Control-standardized SUVrs were compared across Down syndrome groups of Aβ-negative (A-) (AβL < 13.3), subthreshold A+ (13.3 ≤ AβL < 20) and conventionally A+ (AβL ≥ 20) individuals. The subthreshold A + group was identified as having significantly higher Aβ burden compared to the A- group, but not high enough to satisfy a conventional A + classification. Results A large-sized association that survived adjustment for chronological age, mental age (assessed using the Peabody Picture Vocabulary Test), and imaging site was observed between AβL and AV-1451 within each Braak region (p < .05). The A + group showed significantly higher AV-1451 retention across all Braak regions compared to the A- and subthreshold A + groups (p < .05). The subthreshold A + group showed significantly higher AV-1451 retention in Braak regions I-III compared to an age-matched sample from the A- group (p < .05). Discussion These results show that even the earliest detectable Aβ accumulation in Down syndrome is accompanied by elevated tau in the early Braak stage regions. This early detection of tau can help characterize the tau accumulation phase during preclinical Alzheimer’s disease progression in Down syndrome and suggests that there may be a relatively narrow window after Aβ accumulation begins to prevent the downstream cascade of events that leads to Alzheimer’s disease.
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Affiliation(s)
- Matthew D Zammit
- University of Wisconsin-Madison Waisman Center, Madison, WI, USA; University of Wisconsin-Madison Department of Medical Physics, Madison, WI, USA.
| | - Dana L Tudorascu
- University of Pittsburgh Department of Psychiatry, Pittsburgh, PA, USA
| | - Charles M Laymon
- University of Pittsburgh Department of Radiology, Pittsburgh, PA, USA; University of Pittsburgh Department of Bioengineering, Pittsburgh, PA, USA
| | - Sigan L Hartley
- University of Wisconsin-Madison Waisman Center, Madison, WI, USA
| | - Paul A Ellison
- University of Wisconsin-Madison Department of Medical Physics, Madison, WI, USA
| | - Shahid H Zaman
- Cambridge Intellectual Disability Research Group, University of Cambridge, Cambridge, UK
| | - Beau M Ances
- Washington University in St. Louis Department of Neurology, St. Louis, MO, USA
| | - Sterling C Johnson
- University of Wisconsin-Madison Alzheimer's Disease Research Center, Madison, WI, USA
| | - Charles K Stone
- University of Wisconsin-Madison Department of Medicine, Madison, WI, USA
| | | | - Chester A Mathis
- University of Pittsburgh Department of Psychiatry, Pittsburgh, PA, USA
| | - William E Klunk
- University of Pittsburgh Department of Psychiatry, Pittsburgh, PA, USA
| | - Ann D Cohen
- University of Pittsburgh Department of Psychiatry, Pittsburgh, PA, USA
| | - Benjamin L Handen
- University of Pittsburgh Department of Psychiatry, Pittsburgh, PA, USA
| | - Bradley T Christian
- University of Wisconsin-Madison Waisman Center, Madison, WI, USA; University of Wisconsin-Madison Department of Medical Physics, Madison, WI, USA
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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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Zammit MD, Tudorascu DL, Laymon CM, Hartley SL, Zaman SH, Ances BM, Johnson SC, Stone CK, Mathis CA, Klunk WE, Cohen AD, Handen BL, Christian BT. PET measurement of longitudinal amyloid load identifies the earliest stages of amyloid-beta accumulation during Alzheimer's disease progression in Down syndrome. Neuroimage 2021; 228:117728. [PMID: 33421595 PMCID: PMC7953340 DOI: 10.1016/j.neuroimage.2021.117728] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 12/14/2020] [Accepted: 12/27/2020] [Indexed: 12/17/2022] Open
Abstract
Introduction: Adults with Down syndrome (DS) are predisposed to Alzheimer’s disease (AD) and reveal early amyloid beta (Aβ) pathology in the brain. Positron emission tomography (PET) provides an in vivo measure of Aβ throughout the AD continuum. Due to the high prevalence of AD in DS, there is need for longitudinal imaging studies of Aβ to better characterize the natural history of Aβ accumulation, which will aid in the staging of this population for clinical trials aimed at AD treatment and prevention. Methods: Adults with DS (N = 79; Mean age (SD) = 42.7 (7.28) years) underwent longitudinal [C-11]Pittsburgh compound B (PiB) PET. Global Aβ burden was quantified using the amyloid load metric (AβL). Modeled PiB images were generated from the longitudinal AβL data to visualize which regions are most susceptible to Aβ accumulation in DS. AβL change was evaluated across Aβ(−), Aβ-converter, and Aβ(+) groups to assess longitudinal Aβ trajectories during different stages of AD-pathology progression. AβL change values were used to identify Aβ-accumulators within the Aβ(−) group prior to reaching the Aβ(+) threshold (previously reported as 20 AβL) which would have resulted in an Aβ-converter classification. With knowledge of trajectories of Aβ(−) accumulators, a new cutoff of Aβ(+) was derived to better identify subthreshold Aβ accumulation in DS. Estimated sample sizes necessary to detect a 25% reduction in annual Aβ change with 80% power (alpha 0.01) were determined for different groups of Aβ-status. Results: Modeled PiB images revealed the striatum, parietal cortex and precuneus as the regions with earliest detected Aβ accumulation in DS. The Aβ(−) group had a mean AβL change of 0.38 (0.58) AβL/year, while the Aβ-converter and Aβ(+) groups had change of 2.26 (0.66) and 3.16 (1.34) AβL/year, respectively. Within the Aβ(−) group, Aβ-accumulators showed no significant difference in AβL change values when compared to Aβ-converter and Aβ(+) groups. An Aβ(+) cutoff for subthreshold Aβ accumulation was derived as 13.3 AβL. The estimated sample size necessary to detect a 25% reduction in Aβ was 79 for Aβ(−) accumulators and 59 for the Aβ-converter/Aβ(+) group in DS. Conclusion: Longitudinal AβL changes were capable of distinguishing Aβ accumulators from non-accumulators in DS. Longitudinal imaging allowed for identification of subthreshold Aβ accumulation in DS during the earliest stages of AD-pathology progression. Detection of active Aβ deposition evidenced by subthreshold accumulation with longitudinal imaging can identify DS individuals at risk for AD development at an earlier stage.
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Affiliation(s)
- Matthew D Zammit
- University of Wisconsin-Madison, Waisman Center, 1500 Highland Avenue, Madison, WI 53705, United States.
| | - Dana L Tudorascu
- University of Pittsburgh, Department of Psychiatry, Pittsburgh, PA, United States.
| | - Charles M Laymon
- University of Pittsburgh, Department of Radiology, Pittsburgh, PA, United States; University of Pittsburgh, Department of Bioengineering, Pittsburgh, PA, United States.
| | - Sigan L Hartley
- University of Wisconsin-Madison, Waisman Center, 1500 Highland Avenue, Madison, WI 53705, United States.
| | - Shahid H Zaman
- Cambridge Intellectual Disability Research Group, University of Cambridge, Cambridge, United Kingdom.
| | - Beau M Ances
- Washington University in St. Louis Department of Neurology, St. Louis, MO, United States.
| | - Sterling C Johnson
- University of Wisconsin-Madison, Alzheimer's Disease Research Center, Madison, WI, United States.
| | - Charles K Stone
- University of Wisconsin-Madison, Department of Medicine, Madison, WI, United States.
| | - Chester A Mathis
- University of Pittsburgh, Department of Psychiatry, Pittsburgh, PA, United States.
| | - William E Klunk
- University of Pittsburgh, Department of Psychiatry, Pittsburgh, PA, United States
| | - Ann D Cohen
- University of Pittsburgh, Department of Psychiatry, Pittsburgh, PA, United States.
| | - Benjamin L Handen
- University of Pittsburgh, Department of Psychiatry, Pittsburgh, PA, United States.
| | - Bradley T Christian
- University of Wisconsin-Madison, Waisman Center, 1500 Highland Avenue, Madison, WI 53705, United States.
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Ikonomovic MD, Buckley CJ, Abrahamson EE, Kofler JK, Mathis CA, Klunk WE, Farrar G. Post-mortem analyses of PiB and flutemetamol in diffuse and cored amyloid-β plaques in Alzheimer's disease. Acta Neuropathol 2020; 140:463-476. [PMID: 32772265 PMCID: PMC7498488 DOI: 10.1007/s00401-020-02175-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 05/27/2020] [Accepted: 06/04/2020] [Indexed: 01/22/2023]
Abstract
Specificity and sensitivity of positron emission tomography (PET) radiopharmaceuticals targeting fibrillar amyloid-β (Aβ) deposits is high for detection of neuritic Aβ plaques, a mature form of Aβ deposits which often have dense Aβ core (i.e., cored plaques). However, imaging-to-autopsy validation studies of amyloid PET radioligands have identified several false positive cases all of which had mainly diffuse Aβ plaques (i.e., plaques without neuritic pathology or dense amyloid core), and high amyloid PET signal was reported in the striatum where diffuse plaques predominate in Alzheimer's disease (AD). Relative contributions of different plaque types to amyloid PET signal is unclear, particularly in neocortical areas where they are intermixed in AD. In vitro binding assay and autoradiography were performed using [3H]flutemetamol and [3H]Pittsburgh Compound-B (PiB) in frozen brain homogenates from 30 autopsy cases including sporadic AD and non-AD controls with a range of brain Aβ burden and plaque density. Fixed tissue sections of frontal cortex and caudate from 10 of the AD cases were processed for microscopy using fluorescent derivatives of flutemetamol (cyano-flutemetamol) and PiB (cyano-PiB) and compared to Aβ immunohistochemistry and pan-amyloid (X-34) histology. Using epifluorescence microscopy, percent area coverage and fluorescence output values of cyano-PiB- and cyano-flutemetamol-labeled plaques in two-dimensional microscopic fields were then calculated and combined to obtain integrated density measurements. Using confocal microscopy, we analysed total fluorescence output of the entire three-dimensional volume of individual cored plaques and diffuse plaques labeled with cyano-flutemetamol or cyano-PiB. [3H]Flutemetamol and [3H]PiB binding values in tissue homogenates correlated strongly and their binding pattern in tissue sections, as seen on autoradiograms, overlapped the pattern of Aβ-immunoreactive plaques on directly adjacent sections. Cyano-flutemetamol and cyano-PiB fluorescence was prominent in cored plaques and less so in diffuse plaques. Across brain regions and cases, percent area coverage of cyano-flutemetamol-labeled plaques correlated strongly with cyano-PiB-labeled and Aβ-immunoreactive plaques. For both ligands, plaque burden, calculated as percent area coverage of all Aβ plaque types, was similar in frontal cortex and caudate regions, while integrated density values were significantly greater in frontal cortex, which contained both cored plaques and diffuse plaques, compared to the caudate, which contained only diffuse plaques. Three-dimensional analysis of individual plaques labeled with either ligand showed that total fluorescence output of a single cored plaque was equivalent to total fluorescence output of approximately three diffuse plaques of similar volume. Our results indicate that [18F]flutemetamol and [11C]PiB PET signal is influenced by both diffuse plaques and cored plaques, and therefore is likely a function of plaque size and density of Aβ fibrils in plaques. Brain areas with large volumes/frequencies of diffuse plaques could yield [18F]flutemetamol and [11C]PiB PET retention levels comparable to brain regions with a lower volume/frequency of cored plaques.
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Affiliation(s)
- Milos D Ikonomovic
- Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, Pittsburgh, PA, USA.
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA.
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA.
- University of Pittsburgh School of Medicine, Thomas Detre Hall of the WPIC, Room 1421, 3811 O'Hara Street, Pittsburgh, 15213-2593, PA, USA.
| | | | - Eric E Abrahamson
- Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, Pittsburgh, PA, USA
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Julia K Kofler
- Department of Pathology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Chester A Mathis
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - William E Klunk
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
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9
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Influence of apolipoprotein-E genotype on brain amyloid load and longitudinal trajectories. Neurobiol Aging 2020; 94:111-120. [PMID: 32603776 DOI: 10.1016/j.neurobiolaging.2020.05.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 05/21/2020] [Accepted: 05/23/2020] [Indexed: 12/23/2022]
Abstract
To characterize the influence of apolipoprotein-E (APOE) genotype on cerebral Aβ load and longitudinal Aβ trajectories, [11C]Pittsburgh compound-B (PiB) positron emission tomography (PET) imaging was used to assess amyloid load in a clinically heterogeneous cohort of 428 elderly participants with known APOE genotype. Serial [11C]PiB data and a repeated measures model were used to model amyloid trajectories in a subset of 235 participants classified on the basis of APOE genotype. We found that APOE-ε4 was associated with increased Aβ burden and an earlier age of onset of Aβ positivity, whereas APOE-ε2 appeared to have modest protective effects against Aβ. APOE class did not predict rates of Aβ accumulation. The present study suggests that APOE modifies Alzheimer's disease risk through a direct influence on amyloidogenic processes, which manifests as an earlier age of onset of Aβ positivity, although it is likely that other genetic, environmental, and lifestyle factors are important.
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Lesot MJ, Vieira S, Reformat MZ, Carvalho JP, Wilbik A, Bouchon-Meunier B, Yager RR. Statistical Methods for Processing Neuroimaging Data from Two Different Sites with a Down Syndrome Population Application. INFORMATION PROCESSING AND MANAGEMENT OF UNCERTAINTY IN KNOWLEDGE-BASED SYSTEMS 2020. [PMCID: PMC7274647 DOI: 10.1007/978-3-030-50153-2_28] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Harmonization of magnetic resonance imaging (MRI) and positron emission tomography (PET) scans from multi-scanner and multi-site studies presents a challenging problem. We applied the Removal of Artificial Voxel Effect by Linear regression (RAVEL) method to normalize T1-MRI intensities collected on two different scanners across two different sites as part of the Neurodegeneration in Aging Down syndrome (NiAD) study. The effects on FreeSurfer regional cortical thickness and volume outcome measures, in addition to FreeSurfer-based regional quantification of amyloid PET standardized uptake value ratio (SUVR) outcomes, were evaluated. A neuroradiologist visually assessed the accuracy of FreeSurfer hippocampus segmentations with and without the application of RAVEL. Quantitative results demonstrated that the application of RAVEL intensity normalization prior to running FreeSurfer significantly impacted both FreeSurfer volume and cortical thickness outcome measures. Visual assessment demonstrated that the application of RAVEL significantly improved FreeSurfer hippocampal segmentation accuracy. The RAVEL intensity normalization had little impact on PET SUVR measures.
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Affiliation(s)
| | - Susana Vieira
- IDMEC, IST, Universidade de Lisboa, Lisbon, Portugal
| | | | | | - Anna Wilbik
- Eindhoven University of Technology, Eindhoven, The Netherlands
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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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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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