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Stevens DA, Workman CI, Kuwabara H, Butters MA, Savonenko A, Nassery N, Gould N, Kraut M, Joo JH, Kilgore J, Kamath V, Holt DP, Dannals RF, Nandi A, Onyike CU, Smith GS. Regional amyloid correlates of cognitive performance in ageing and mild cognitive impairment. Brain Commun 2022; 4:fcac016. [PMID: 35233522 PMCID: PMC8882008 DOI: 10.1093/braincomms/fcac016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 12/03/2021] [Accepted: 02/02/2022] [Indexed: 11/13/2022] Open
Abstract
Beta-amyloid deposition is one of the earliest pathological markers associated with Alzheimer's disease. Mild cognitive impairment in the setting of beta-amyloid deposition is considered to represent a preclinical manifestation of Alzheimer's disease. In vivo imaging studies are unique in their potential to advance our understanding of the role of beta-amyloid deposition in cognitive deficits in Alzheimer's disease and in mild cognitive impairment. Previous work has shown an association between global cortical measures of beta-amyloid deposition ('amyloid positivity') in mild cognitive impairment with greater cognitive deficits and greater risk of progression to Alzheimer's disease. The focus of the present study was to examine the relationship between the regional distribution of beta-amyloid deposition and specific cognitive deficits in people with mild cognitive impairment and cognitively normal elderly individuals. Forty-seven participants with multi-domain, amnestic mild cognitive impairment (43% female, aged 57-82 years) and 37 healthy, cognitively normal comparison subjects (42% female, aged 55-82 years) underwent clinical and neuropsychological assessments and high-resolution positron emission tomography with the radiotracer 11C-labelled Pittsburgh compound B to measure beta-amyloid deposition. Brain-behaviour partial least-squares analysis was conducted to identify spatial patterns of beta-amyloid deposition that correlated with the performance on neuropsychological assessments. Partial least-squares analysis identified a single significant (P < 0.001) latent variable which accounted for 80% of the covariance between demographic and cognitive measures and beta-amyloid deposition. Performance in immediate verbal recall (R = -0.46 ± 0.07, P < 0.001), delayed verbal recall (R = -0.39 ± 0.09, P < 0.001), immediate visual-spatial recall (R = -0.39 ± 0.08, P < 0.001), delayed visual-spatial recall (R = -0.45 ± 0.08, P < 0.001) and semantic fluency (R = -0.33 ± 0.11, P = 0.002) but not phonemic fluency (R = -0.05 ± 0.12, P < 0.705) negatively covaried with beta-amyloid deposition in the identified regions. Partial least-squares analysis of the same cognitive measures with grey matter volumes showed similar associations in overlapping brain regions. These findings suggest that the regional distribution of beta-amyloid deposition and grey matter volumetric decreases is associated with deficits in executive function and memory in mild cognitive impairment. Longitudinal analysis of these relationships may advance our understanding of the role of beta-amyloid deposition in relation to grey matter volumetric decreases in cognitive decline.
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Affiliation(s)
- Daniel A. Stevens
- Division of Geriatric Psychiatry and Neuropsychiatry, Department of Psychiatry and Behavioral Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Clifford I. Workman
- Division of Geriatric Psychiatry and Neuropsychiatry, Department of Psychiatry and Behavioral Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Hiroto Kuwabara
- Division of Nuclear Medicine and Molecular Imaging, Russell H. Morgan Department of Radiology and Radiological Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Meryl A. Butters
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Alena Savonenko
- Department of Pathology (Neuropathology), School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Najilla Nassery
- Department of General Internal Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Neda Gould
- Division of Geriatric Psychiatry and Neuropsychiatry, Department of Psychiatry and Behavioral Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Michael Kraut
- Division of Neuroradiology, Russell H. Morgan Department of Radiology and Radiological Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Jin Hui Joo
- Division of Geriatric Psychiatry and Neuropsychiatry, Department of Psychiatry and Behavioral Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Jessica Kilgore
- Division of Geriatric Psychiatry and Neuropsychiatry, Department of Psychiatry and Behavioral Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Vidya Kamath
- Division of Geriatric Psychiatry and Neuropsychiatry, Department of Psychiatry and Behavioral Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Daniel P. Holt
- Division of Nuclear Medicine and Molecular Imaging, Russell H. Morgan Department of Radiology and Radiological Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Robert F. Dannals
- Division of Nuclear Medicine and Molecular Imaging, Russell H. Morgan Department of Radiology and Radiological Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Ayon Nandi
- Division of Nuclear Medicine and Molecular Imaging, Russell H. Morgan Department of Radiology and Radiological Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Chiadi U. Onyike
- Division of Geriatric Psychiatry and Neuropsychiatry, Department of Psychiatry and Behavioral Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
- Department of Neurology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Gwenn S. Smith
- Division of Geriatric Psychiatry and Neuropsychiatry, Department of Psychiatry and Behavioral Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
- Division of Nuclear Medicine and Molecular Imaging, Russell H. Morgan Department of Radiology and Radiological Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
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Albright J, Ashford MT, Jin C, Neuhaus J, Rabinovici GD, Truran D, Maruff P, Mackin RS, Nosheny RL, Weiner MW. Machine learning approaches to predicting amyloid status using data from an online research and recruitment registry: The Brain Health Registry. ALZHEIMER'S & DEMENTIA (AMSTERDAM, NETHERLANDS) 2021; 13:e12207. [PMID: 34136635 PMCID: PMC8190559 DOI: 10.1002/dad2.12207] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 05/11/2021] [Indexed: 12/16/2022]
Abstract
INTRODUCTION This study investigated the extent to which subjective and objective data from an online registry can be analyzed using machine learning methodologies to predict the current brain amyloid beta (Aβ) status of registry participants. METHODS We developed and optimized machine learning models using data from up to 664 registry participants. Models were assessed on their ability to predict Aβ positivity using the results of positron emission tomography as ground truth. RESULTS Study partner-assessed Everyday Cognition score was preferentially selected for inclusion in the models by a feature selection algorithm during optimization. DISCUSSION Our results suggest that inclusion of study partner assessments would increase the ability of machine learning models to predict Aβ positivity.
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Affiliation(s)
| | - Miriam T. Ashford
- Department of Veterans Affairs Medical CenterNorthern California Institute for Research and Education (NCIRE)San FranciscoCaliforniaUSA
- Department of Veterans Affairs Medical CenterCenter for Imaging and Neurodegenerative DiseasesSan FranciscoCaliforniaUSA
| | - Chengshi Jin
- University of California San Francisco Department of Epidemiology and BiostatisticsSan FranciscoCaliforniaUSA
| | - John Neuhaus
- University of California San Francisco Department of Epidemiology and BiostatisticsSan FranciscoCaliforniaUSA
| | - Gil D. Rabinovici
- Department of Radiology and Biomedical ImagingUniversity of CaliforniaSan FranciscoCaliforniaUSA
- Department of NeurologyUniversity of California San FranciscoSan FranciscoCaliforniaUSA
| | - Diana Truran
- Department of Veterans Affairs Medical CenterNorthern California Institute for Research and Education (NCIRE)San FranciscoCaliforniaUSA
- Department of Veterans Affairs Medical CenterCenter for Imaging and Neurodegenerative DiseasesSan FranciscoCaliforniaUSA
| | | | - R. Scott Mackin
- Department of Veterans Affairs Medical CenterCenter for Imaging and Neurodegenerative DiseasesSan FranciscoCaliforniaUSA
- Department of PsychiatryUniversity of California San FranciscoSan FranciscoCaliforniaUSA
| | - Rachel L. Nosheny
- Department of Veterans Affairs Medical CenterCenter for Imaging and Neurodegenerative DiseasesSan FranciscoCaliforniaUSA
- Department of PsychiatryUniversity of California San FranciscoSan FranciscoCaliforniaUSA
| | - Michael W. Weiner
- Department of Veterans Affairs Medical CenterNorthern California Institute for Research and Education (NCIRE)San FranciscoCaliforniaUSA
- Department of Veterans Affairs Medical CenterCenter for Imaging and Neurodegenerative DiseasesSan FranciscoCaliforniaUSA
- Department of Radiology and Biomedical ImagingUniversity of CaliforniaSan FranciscoCaliforniaUSA
- Department of NeurologyUniversity of California San FranciscoSan FranciscoCaliforniaUSA
- Department of PsychiatryUniversity of California San FranciscoSan FranciscoCaliforniaUSA
- Department of MedicineUniversity of California San FranciscoSan FranciscoCaliforniaUSA
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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: 27] [Impact Index Per Article: 6.8] [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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Wang X, Huang W, Su L, Xing Y, Jessen F, Sun Y, Shu N, Han Y. Neuroimaging advances regarding subjective cognitive decline in preclinical Alzheimer's disease. Mol Neurodegener 2020; 15:55. [PMID: 32962744 PMCID: PMC7507636 DOI: 10.1186/s13024-020-00395-3] [Citation(s) in RCA: 97] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 08/07/2020] [Indexed: 12/15/2022] Open
Abstract
Subjective cognitive decline (SCD) is regarded as the first clinical manifestation in the Alzheimer’s disease (AD) continuum. Investigating populations with SCD is important for understanding the early pathological mechanisms of AD and identifying SCD-related biomarkers, which are critical for the early detection of AD. With the advent of advanced neuroimaging techniques, such as positron emission tomography (PET) and magnetic resonance imaging (MRI), accumulating evidence has revealed structural and functional brain alterations related to the symptoms of SCD. In this review, we summarize the main imaging features and key findings regarding SCD related to AD, from local and regional data to connectivity-based imaging measures, with the aim of delineating a multimodal imaging signature of SCD due to AD. Additionally, the interaction of SCD with other risk factors for dementia due to AD, such as age and the Apolipoprotein E (ApoE) ɛ4 status, has also been described. Finally, the possible explanations for the inconsistent and heterogeneous neuroimaging findings observed in individuals with SCD are discussed, along with future directions. Overall, the literature reveals a preferential vulnerability of AD signature regions in SCD in the context of AD, supporting the notion that individuals with SCD share a similar pattern of brain alterations with patients with mild cognitive impairment (MCI) and dementia due to AD. We conclude that these neuroimaging techniques, particularly multimodal neuroimaging techniques, have great potential for identifying the underlying pathological alterations associated with SCD. More longitudinal studies with larger sample sizes combined with more advanced imaging modeling approaches such as artificial intelligence are still warranted to establish their clinical utility.
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Affiliation(s)
- Xiaoqi Wang
- Department of Neurology, Xuanwu Hospital of Capital Medical University, Beijing, 100053, China.,Center of Alzheimer's Disease, Beijing Institute for Brain Disorders, Beijing, China
| | - Weijie Huang
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, 100875, China.,Center for Collaboration and Innovation in Brain and Learning Sciences, Beijing Normal University, Beijing, China.,Beijing Key Laboratory of Brain Imaging and Connectomics, Beijing Normal University, Beijing, China
| | - Li Su
- Department of Psychiatry, University of Cambridge, Cambridge, UK.,Sino-Britain Centre for Cognition and Ageing Research, Southwest University, Chongqing, China
| | - Yue Xing
- Radiological Sciences, Division of Clinical Neuroscience, University of Nottingham, Nottingham, UK
| | - Frank Jessen
- Department of Psychiatry and Psychotherapy, Medical Faculty, University of Cologne, 50937, Cologne, Germany.,German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.,Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Yu Sun
- Department of Neurology, Xuanwu Hospital of Capital Medical University, Beijing, 100053, China. .,Center of Alzheimer's Disease, Beijing Institute for Brain Disorders, Beijing, China.
| | - Ni Shu
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, 100875, China. .,Center for Collaboration and Innovation in Brain and Learning Sciences, Beijing Normal University, Beijing, China. .,Beijing Key Laboratory of Brain Imaging and Connectomics, Beijing Normal University, Beijing, China.
| | - Ying Han
- Department of Neurology, Xuanwu Hospital of Capital Medical University, Beijing, 100053, China. .,Center of Alzheimer's Disease, Beijing Institute for Brain Disorders, Beijing, China. .,National Clinical Research Center for Geriatric Disorders, Beijing, China.
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Miao C, Dong F, Jia L, Li W, Wang M, Zheng QH, Xu Z. Radiosynthesis of a carbon-11-labeled AMPAR allosteric modulator as a new PET radioligand candidate for imaging of Alzheimer's disease. Bioorg Med Chem Lett 2019; 29:1177-1181. [PMID: 30922660 DOI: 10.1016/j.bmcl.2019.03.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 03/13/2019] [Accepted: 03/20/2019] [Indexed: 11/19/2022]
Abstract
To develop PET tracers for imaging of Alzheimer's disease, a new carbon-11-labeled AMPAR allosteric modulator 4-cyclopropyl-7-(3-[11C]methoxyphenoxy)-3,4-dihydro-2H-benzo[e][1,2,4]thiadiazine 1,1-dioxide ([11C]8) has been synthesized. The reference standard 4-cyclopropyl-7-(3-methoxyphenoxy)-3,4-dihydro-2H-benzo[e][1,2,4]thiadiazine 1,1-dioxide (8) and its corresponding desmethylated precursor 4-cyclopropyl-7-(3-hydroxyphenoxy)-3,4-dihydro-2H-benzo[e][1,2,4]thiadiazine 1,1-dioxide (9) were synthesized from 4-methoxyabiline and chlorosulfonyl isocyanate in eight and nine steps with 3% and 1% overall chemical yield, respectively. The target tracer [11C]8 was prepared from the precursor 9 with [11C]CH3OTf through O-[11C]methylation and isolated by HPLC combined with SPE in 10-15% radiochemical yield, based on [11C]CO2 and decay corrected to end of bombardment (EOB). The radiochemical purity was >99%, and the molar activity (AM) at EOB was 370-740 GBq/μmol with a total synthesis time of 35-40-minutes from EOB.
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Affiliation(s)
- Caihong Miao
- Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education, College of Chemistry and Environmental Science, Hebei University, Baoding, Hebei 071002, China
| | - Fugui Dong
- Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education, College of Chemistry and Environmental Science, Hebei University, Baoding, Hebei 071002, China
| | - Limeng Jia
- Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education, College of Chemistry and Environmental Science, Hebei University, Baoding, Hebei 071002, China
| | - Wei Li
- Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education, College of Chemistry and Environmental Science, Hebei University, Baoding, Hebei 071002, China
| | - Min Wang
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 1345 West 16th Street, Room 202, Indianapolis, IN 46202, USA
| | - Qi-Huang Zheng
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 1345 West 16th Street, Room 202, Indianapolis, IN 46202, USA.
| | - Zhidong Xu
- Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education, College of Chemistry and Environmental Science, Hebei University, Baoding, Hebei 071002, China; College of Chemical & Pharmaceutical Engineering, Key Laboratory of Molecular Chemistry for Medicine of Hebei Province, Hebei University of Science & Technology, Shijiazhuang, Hebei 050018, China; Shijiazhuang Vince Pharmatech Co., Ltd., Shijiazhuang, Hebei 050030, China.
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Synthesis of carbon-11-labeled 5-HT6R antagonists as new candidate PET radioligands for imaging of Alzheimer’s disease. Bioorg Med Chem Lett 2018; 28:1836-1841. [DOI: 10.1016/j.bmcl.2018.04.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 04/04/2018] [Accepted: 04/06/2018] [Indexed: 12/31/2022]
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Gao M, Wang M, Zheng QH. Synthesis of carbon-11-labeled CK1 inhibitors as new potential PET radiotracers for imaging of Alzheimer's disease. Bioorg Med Chem Lett 2018; 28:2234-2238. [PMID: 29859907 DOI: 10.1016/j.bmcl.2018.05.053] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 05/27/2018] [Accepted: 05/28/2018] [Indexed: 12/13/2022]
Abstract
The reference standards methyl 3-((2,2-difluoro-5H-[1,3]dioxolo[4',5':4,5]benzo[1,2-d]imidazol-6-yl)carbamoyl)benzoate (5a) and N-(2,2-difluoro-5H-[1,3]dioxolo[4',5':4,5]benzo[1,2-d]imidazol-6-yl)-3-methoxybenzamide (5c), and their corresponding desmethylated precursors 3-((2,2-difluoro-5H-[1,3]dioxolo[4',5':4,5]benzo[1,2-d]imidazol-6-yl)carbamoyl)benzoic acid (6a) and N-(2,2-difluoro-5H-[1,3]dioxolo[4',5':4,5]benzo[1,2-d]imidazol-6-yl)-3-hydroxybenzamide (6b), were synthesized from 5-amino-2,2-difluoro-1,3-benzodioxole and 3-substituted benzoic acids in 5 and 6 steps with 33% and 11%, 30% and 7% overall chemical yield, respectively. Carbon-11-labeled casein kinase 1 (CK1) inhibitors, [11C]methyl 3-((2,2-difluoro-5H-[1,3]dioxolo[4',5':4,5]benzo[1,2-d]imidazol-6-yl)carbamoyl)benzoate ([11C]5a) and N-(2,2-difluoro-5H-[1,3]dioxolo[4',5':4,5]benzo[1,2-d]imidazol-6-yl)-3-[11C]methoxybenzamide ([11C]5c), were prepared from their O-desmethylated precursor 6a or 6b with [11C]CH3OTf through O-[11C]methylation and isolated by HPLC combined with SPE in 40-45% radiochemical yield, based on [11C]CO2 and decay corrected to end of bombardment (EOB). The radiochemical purity was >99%, and the molar activity (MA) at EOB was 370-740 GBq/μmol with a total synthesis time of ∼40-min from EOB.
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Affiliation(s)
- Mingzhang Gao
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 1345 West 16th Street, Room 202, Indianapolis, IN 46202, USA
| | - Min Wang
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 1345 West 16th Street, Room 202, Indianapolis, IN 46202, USA
| | - Qi-Huang Zheng
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 1345 West 16th Street, Room 202, Indianapolis, IN 46202, USA.
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Pandya S, Kuceyeski A, Raj A. The Brain's Structural Connectome Mediates the Relationship between Regional Neuroimaging Biomarkers in Alzheimer's Disease. J Alzheimers Dis 2018; 55:1639-1657. [PMID: 27911289 DOI: 10.3233/jad-160090] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Alzheimer's disease (AD), one of the most common causes of dementia in adults, is a progressive neurodegenerative disorder exhibiting well-defined neuropathological hallmarks. It is known that disease pathology involves misfolded amyloid-β (Aβ) and tau proteins, and exhibits a relatively stereotyped progression over decades. The relationship between AD neuropathological hallmarks (Aβ, hypometabolism, and tau proteins) and imaging biomarkers (MRI, AV-45/FDG-PET) is not fully understood. In addition, biomarker pathologies are oftentimes discordant, wherein it may show varying levels of abnormality across brain regions. Evidence based on recent elucidation of trans-neuronal "prion-like" transmission and other available data already suggests that disease spread follows the brain's fiber connectivity network. Thereby, the brain's connectome information can be used to predict the process of disease spread in AD. A recently established mathematical model of AD pathology spread using a connectome-based network diffusion model was successful in encapsulating neurodegenerative progression. Motivated by these network-based findings, the current study explores whether and how network connectivity mediates the interactions between various AD biomarkers. We hypothesized that the structural connectivity matrix will mediate the cross-sectional association between regional AD-associated hypometabolism and Aβ deposition. Given recent reports of inherent or lifetime activity of brain regions as strong predictors of Aβ deposition in patients, we also tested whether healthy metabolism exerts a network-mediated effect on Aβ deposition and hypometabolism in AD patients. We found that regional Aβ deposition is best predicted by a linear combination of both regional healthy local metabolism and connectome-mediated regional healthy metabolism.
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9
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Gao M, Wang M, Zheng QH. Synthesis of carbon-11-labeled isonicotinamides as new potential PET agents for imaging of GSK-3 enzyme in Alzheimer’s disease. Bioorg Med Chem Lett 2017; 27:740-743. [DOI: 10.1016/j.bmcl.2017.01.041] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 01/12/2017] [Accepted: 01/13/2017] [Indexed: 12/29/2022]
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Neuroimaging in Alzheimer's disease: preclinical challenges toward clinical efficacy. Transl Res 2016; 175:37-53. [PMID: 27033146 DOI: 10.1016/j.trsl.2016.03.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 03/05/2016] [Accepted: 03/06/2016] [Indexed: 12/21/2022]
Abstract
The scope of this review focuses on recent applications in preclinical and clinical magnetic resonance imaging (MRI) toward accomplishing the goals of early detection and responses to therapy in animal models of Alzheimer's disease (AD). Driven by the outstanding efforts of the Alzheimer's Disease Neuroimaging Initiative (ADNI), a truly invaluable resource, the initial use of MRI in AD imaging has been to assess changes in brain anatomy, specifically assessing brain shrinkage and regional changes in white matter tractography using diffusion tensor imaging. However, advances in MRI have led to multiple efforts toward imaging amyloid beta plaques first without and then with the use of MRI contrast agents. These technological advancements have met with limited success and are not yet appropriate for the clinic. Recent developments in molecular imaging inclusive of high-power liposomal-based MRI contrast agents as well as fluorine 19 ((19)F) MRI and manganese enhanced MRI have begun to propel promising advances toward not only plaque imaging but also using MRI to detect perturbations in subcellular processes occurring within the neuron. This review concludes with a discussion about the necessity for the development of novel preclinical models of AD that better recapitulate human AD for the imaging to truly be meaningful and for substantive progress to be made toward understanding and effectively treating AD. Furthermore, the continued support of outstanding programs such as ADNI as well as the development of novel molecular imaging agents and MRI fast scanning sequences will also be requisite to effectively translate preclinical findings to the clinic.
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Widespread white matter and conduction defects in PSEN1-related spastic paraparesis. Neurobiol Aging 2016; 47:201-209. [PMID: 27614114 DOI: 10.1016/j.neurobiolaging.2016.07.030] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 07/07/2016] [Accepted: 07/29/2016] [Indexed: 02/08/2023]
Abstract
The mechanisms underlying presenilin 1 (PSEN1) mutation-associated spastic paraparesis (SP) are not clear. We compared diffusion and volumetric magnetic resonance measures between 3 persons with SP associated with the A431E mutation and 7 symptomatic persons with PSEN1 mutations without SP matched for symptom duration. We performed amyloid imaging and central motor and somatosensory conduction studies in 1 subject with SP. We found decreases in fractional anisotropy and increases in mean diffusivity in widespread white-matter areas including the corpus callosum, occipital, parietal, and frontal lobes in PSEN1 mutation carriers with SP. Volumetric measures were not different, and amyloid imaging showed low signal in sensorimotor cortex and other areas in a single subject with SP. Electrophysiological studies demonstrated both slowed motor and sensory conduction in the lower extremities in this same subject. Our results suggest that SP in carriers of the A431E PSEN1 mutation is a manifestation of widespread white-matter abnormalities not confined to the corticospinal tract that is at most indirectly related to the mutation's effect on amyloid precursor protein processing and amyloid deposition.
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Insight into the Molecular Imaging of Alzheimer's Disease. Int J Biomed Imaging 2016; 2016:7462014. [PMID: 26880871 PMCID: PMC4736963 DOI: 10.1155/2016/7462014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 12/16/2015] [Indexed: 12/13/2022] Open
Abstract
Alzheimer's disease is a complex neurodegenerative disease affecting millions of individuals worldwide. Earlier it was diagnosed only via clinical assessments and confirmed by postmortem brain histopathology. The development of validated biomarkers for Alzheimer's disease has given impetus to improve diagnostics and accelerate the development of new therapies. Functional imaging like positron emission tomography (PET), single photon emission computed tomography (SPECT), functional magnetic resonance imaging (fMRI), and proton magnetic resonance spectroscopy provides a means of detecting and characterising the regional changes in brain blood flow, metabolism, and receptor binding sites that are associated with Alzheimer's disease. Multimodal neuroimaging techniques have indicated changes in brain structure and metabolic activity, and an array of neurochemical variations that are associated with neurodegenerative diseases. Radiotracer-based PET and SPECT potentially provide sensitive, accurate methods for the early detection of disease. This paper presents a review of neuroimaging modalities like PET, SPECT, and selected imaging biomarkers/tracers used for the early diagnosis of AD. Neuroimaging with such biomarkers and tracers could achieve a much higher diagnostic accuracy for AD and related disorders in the future.
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13
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Li L, Wang XY, Gao FB, Wang L, Xia R, Li ZX, Xing W, Tang BS, Zeng Y, Zhou GF, Zhou HY, Liao WH. Magnetic resonance T2 relaxation time at 7 Tesla associated with amyloid β pathology and age in a double-transgenic mouse model of Alzheimer’s disease. Neurosci Lett 2016; 610:92-7. [DOI: 10.1016/j.neulet.2015.10.058] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 07/26/2015] [Accepted: 10/22/2015] [Indexed: 11/15/2022]
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14
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Shidahara M, Watabe H, Tashiro M, Okamura N, Furumoto S, Watanuki S, Furukawa K, Arakawa Y, Funaki Y, Iwata R, Gonda K, Kudo Y, Arai H, Ishiwata K, Yanai K. Quantitative kinetic analysis of PET amyloid imaging agents [11C]BF227 and [18F]FACT in human brain. Nucl Med Biol 2015; 42:734-44. [DOI: 10.1016/j.nucmedbio.2015.05.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 03/07/2015] [Accepted: 05/01/2015] [Indexed: 11/30/2022]
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15
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Wang M, Gao M, Xu Z, Zheng QH. Synthesis of a PET tau tracer [(11)C]PBB3 for imaging of Alzheimer's disease. Bioorg Med Chem Lett 2015; 25:4587-92. [PMID: 26323870 DOI: 10.1016/j.bmcl.2015.08.053] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 08/17/2015] [Accepted: 08/20/2015] [Indexed: 11/17/2022]
Abstract
The authentic standard PBB3 and its precursor N-desmethyl-PBB3 as well as TBS-protected N-desmethyl-PBB3 precursor for radiolabeling were synthesized from 5-bromo-2-nitropyridine, acrolein diethyl acetal, 6-methoxy-2-methylbenzothiazole, and diethylchlorophosphate with overall chemical yield 1% in six steps, 2% in five steps, and 1% in six steps, respectively. [(11)C]PBB3 was prepared from either desmethyl-PBB3 or TBS-protected desmethyl-PBB3 with [(11)C]CH3OTf through N-[(11)C]methylation and isolated by HPLC combined with SPE in 20-25% and 15-20% radiochemical yield, respectively, based on [(11)C]CO2 and decay corrected to end of bombardment (EOB). The radiochemical purity was >99%, and the specific activity at EOB was 370-1110 GBq/μmol with a total synthesis time of ~40-min from EOB.
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Affiliation(s)
- Min Wang
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 1345 West 16th Street, Room 202, Indianapolis, IN 46202, USA
| | - Mingzhang Gao
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 1345 West 16th Street, Room 202, Indianapolis, IN 46202, USA
| | - Zhidong Xu
- Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education, College of Chemistry and Environmental Science, Hebei University, Baoding, Hebei 071002, China
| | - Qi-Huang Zheng
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 1345 West 16th Street, Room 202, Indianapolis, IN 46202, USA.
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Gao M, Wang M, Zheng QH. Fully automated synthesis of [18F]T807, a PET tau tracer for Alzheimer’s disease. Bioorg Med Chem Lett 2015; 25:2953-7. [DOI: 10.1016/j.bmcl.2015.05.035] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 05/12/2015] [Accepted: 05/13/2015] [Indexed: 01/14/2023]
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17
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Tambasco N, Nigro P, Romoli M, Simoni S, Parnetti L, Calabresi P. Magnetization transfer MRI in dementia disorders, Huntington's disease and parkinsonism. J Neurol Sci 2015; 353:1-8. [PMID: 25891828 DOI: 10.1016/j.jns.2015.03.025] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2015] [Revised: 02/21/2015] [Accepted: 03/16/2015] [Indexed: 01/10/2023]
Abstract
Magnetic resonance imaging is the most used technique of neuroimaging. Using recent advances in magnetic resonance application it is possible to investigate several changes in neurodegenerative disease. Among different techniques, magnetization-transfer imaging (MTI), a magnetic resonance acquisition protocol assessing the magnetization exchange between protons bound to water and those bound to macromolecules, is able to identify microstructural brain tissue changes peculiar of neurodegenerative diseases. This review provides a report on the MTI technique and its use in the dementia disorders, Huntington's disease and parkinsonisms, comprehensive of the predictive values of MTI in the identification of early-phase disease.
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Affiliation(s)
- Nicola Tambasco
- Clinica Neurologica, Azienda Ospedaliera-Università di Perugia, Perugia, Italy.
| | - Pasquale Nigro
- Clinica Neurologica, Azienda Ospedaliera-Università di Perugia, Perugia, Italy
| | - Michele Romoli
- Clinica Neurologica, Azienda Ospedaliera-Università di Perugia, Perugia, Italy
| | - Simone Simoni
- Clinica Neurologica, Azienda Ospedaliera-Università di Perugia, Perugia, Italy
| | - Lucilla Parnetti
- Clinica Neurologica, Azienda Ospedaliera-Università di Perugia, Perugia, Italy
| | - Paolo Calabresi
- Clinica Neurologica, Azienda Ospedaliera-Università di Perugia, Perugia, Italy; IRCCS Fondazione Santa Lucia, Roma, Italy
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18
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Abstract
Prevention in Alzheimer's disease and other dementias (AD/dementia) is defined on the basis of clinical states and their expressed symptoms. Primary prevention refers to delaying the development of the full-blown state of clinically expressed disease in normal individuals. Current primary prevention research is driven by evidence of AD/dementia protective factors that have emerged from epidemiological studies. The first randomized controlled trials (RCTs) of primary AD/dementia prevention have been designed to test the efficacy and safety of NSAIDs, hormonal therapy, antihypertensive drugs and antioxidants. The experience of these trials has indicated safety concerns as a key issue and highlighted significant design challenges in this type of research. These trials have required large sample sizes and unsustainable costs. There should be consideration given in future trials to enriching study samples with risk factors to increase progression rates to AD/dementia. Innovative strategies will also be needed to recruit and retain subjects given the long follow-up periods, modest perceived benefit and the potential for the risk-benefit ratio to change during the trial. It is foreseeable that regulatory authorities will be presented with primary prevention RCTs for approval and labelling, and that criteria to evaluate such evidence still need to be developed.
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Affiliation(s)
- Howard H Feldman
- Division of Neurology, Department of Medicine, University of British Columbia, Vancouver, BC, Canada
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Matveev SV, Spielmann HP, Metts BM, Chen J, Onono F, Zhu H, Scheff SW, Walker LC, LeVine H. A distinct subfraction of Aβ is responsible for the high-affinity Pittsburgh compound B-binding site in Alzheimer's disease brain. J Neurochem 2014; 131:356-68. [PMID: 24995708 DOI: 10.1111/jnc.12815] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 06/18/2014] [Accepted: 06/29/2014] [Indexed: 12/27/2022]
Abstract
The positron emission tomography (PET) ligand (11) C-labeled Pittsburgh compound B (PIB) is used to image β-amyloid (Aβ) deposits in the brains of living subjects with the intent of detecting early stages of Alzheimer's disease (AD). However, deposits of human-sequence Aβ in amyloid precursor protein transgenic mice and non-human primates bind very little PIB. The high stoichiometry of PIB:Aβ binding in human AD suggests that the PIB-binding site may represent a particularly pathogenic entity and/or report local pathologic conditions. In this study, (3) H-PIB was employed to track purification of the PIB-binding site in > 90% yield from frontal cortical tissue of autopsy-diagnosed AD subjects. The purified PIB-binding site comprises a distinct, highly insoluble subfraction of the Aβ in AD brain with low buoyant density because of the sodium dodecyl sulfate-resistant association with a limited subset of brain proteins and lipids with physical properties similar to lipid rafts and to a ganglioside:Aβ complex in AD and Down syndrome brain. Both the protein and lipid components are required for PIB binding. Elucidation of human-specific biological components and pathways will be important in guiding improvement of the animal models for AD and in identifying new potential therapeutic avenues. A lipid-associated subpopulation of Aβ accounts for the high-affinity binding of Pittsburgh compound B (PIB) in Alzheimer's disease brain. Mass spectrometry of the isolated PIB-binding site from frontal cortex identified Aβ peptides and a set of plaque-associated proteins in AD but not age-matched normal brain. The PIB-binding site may represent a particularly pathogenic entity and/or report local pathologic conditions.
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Affiliation(s)
- Sergey V Matveev
- Center on Aging, University of Kentucky, Lexington, Kentucky, USA
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20
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Synthesis of a new fluorine-18-labeled bexarotene analogue for PET imaging of retinoid X receptor. Bioorg Med Chem Lett 2014; 24:1742-7. [DOI: 10.1016/j.bmcl.2014.02.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 02/10/2014] [Accepted: 02/13/2014] [Indexed: 11/20/2022]
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21
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Goldman S. PET imaging of garbage protein in Alzheimer’s disease: does it require reappraisal of brain PET analysis? Eur J Nucl Med Mol Imaging 2014; 41:813-5. [DOI: 10.1007/s00259-014-2740-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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22
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Concise and high-yield synthesis of T808 and T808P for radiosynthesis of [18F]-T808, a PET tau tracer for Alzheimer’s disease. Bioorg Med Chem Lett 2014; 24:254-7. [DOI: 10.1016/j.bmcl.2013.11.025] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 11/06/2013] [Accepted: 11/11/2013] [Indexed: 11/20/2022]
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23
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Bigot C, Vanhoutte G, Verhoye M, Van der Linden A. Magnetization transfer contrast imaging reveals amyloid pathology in Alzheimer's disease transgenic mice. Neuroimage 2013; 87:111-9. [PMID: 24188815 DOI: 10.1016/j.neuroimage.2013.10.056] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 10/19/2013] [Accepted: 10/26/2013] [Indexed: 12/18/2022] Open
Abstract
The presence of amyloid plaques in the brain is one of the pathological hallmarks of Alzheimer's disease, which might already be present in the early stage of the disease. Therefore it is important to track amyloid plaques as early as possible. In this paper, we report magnetization transfer contrast magnetic resonance imaging (MTC MRI) as a novel approach to detect amyloid plaques in vivo. Two mice models, APP/PS1 and BRI, developing amyloid pathology were investigated with MTC MRI, T2 relaxation measurements and immunohistochemistry (IHC). MT-ratios of several brain regions were compared to T2-values and correlated with quantitative IHC, revealing amyloid load and gliosis in different brain regions. APP/PS1 mice develop large compact plaques, resembling late stage Alzheimer's disease, while rather small and diffuse plaques are deposited in BRI mice, reflecting early stage of Alzheimer's disease. We found significantly higher MT-ratio's in the brain of APP/PS1 mice as compared to their controls and similar trends in BRI mice. A region based MT-ratio and IHC analysis and correlations between MT-ratios and quantitative IHC indicate amyloid plaques as the main substrate for altered MT-ratios in transgenic animals. We additionally demonstrated the improved sensitivity of MTC MRI to amyloid pathology as compared to traditional T2 relaxation measurements. Our results suggest that MTC MRI reveals extensive, and potentially even early amyloid pathology. Further unraveling the MT-effect of each pathological feature during each stage of AD might indicate MTC MRI as a useful diagnostic technique.
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Affiliation(s)
- Christian Bigot
- Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1 Uc, 2610 Wilrijk, Antwerp, Belgium.
| | - Greetje Vanhoutte
- Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1 Uc, 2610 Wilrijk, Antwerp, Belgium.
| | - Marleen Verhoye
- Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1 Uc, 2610 Wilrijk, Antwerp, Belgium.
| | - Annemie Van der Linden
- Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1 Uc, 2610 Wilrijk, Antwerp, Belgium.
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24
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Neal KL, Shakerdge NB, Hou SS, Klunk WE, Mathis CA, Nesterov EE, Swager TM, McLean PJ, Bacskai BJ. Development and Screening of Contrast Agents for In Vivo Imaging of Parkinson’s Disease. Mol Imaging Biol 2013; 15:585-95. [DOI: 10.1007/s11307-013-0634-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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25
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Lista S, Faltraco F, Prvulovic D, Hampel H. Blood and plasma-based proteomic biomarker research in Alzheimer's disease. Prog Neurobiol 2013; 101-102:1-17. [DOI: 10.1016/j.pneurobio.2012.06.007] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2011] [Revised: 03/28/2012] [Accepted: 06/18/2012] [Indexed: 12/14/2022]
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26
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The first synthesis of [11C]J147, a new potential PET agent for imaging of Alzheimer’s disease. Bioorg Med Chem Lett 2013; 23:524-7. [DOI: 10.1016/j.bmcl.2012.11.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 10/27/2012] [Accepted: 11/07/2012] [Indexed: 11/23/2022]
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27
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Beuthien-Baumann B, Holthoff VA, Mäding P, Bergmann R, Pawelke B, Holl G, von Kummer R, Kotzerke J, van den Hoff J. 18F-labelled CCR1-receptor antagonist is not suitable for imaging of Alzheimer's disease. Nuklearmedizin 2012; 51:239-43. [PMID: 22684530 DOI: 10.3413/nukmed-0457-12-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Accepted: 05/08/2012] [Indexed: 11/20/2022]
Abstract
UNLABELLED Diagnosis of Alzheimer's disease (AD) with positron emission tomography (PET) using 18F-fluorodeoxyglucose (FDG) relies on typical alterations of brain glucose metabolism which are, however, not disease specific. Amyloid-β imaging has not entered clinical routine yet. Post mortem histological specimen of brain tissue from AD patients revealed enhanced expression of the chemotactic cytocine receptor 1 (CCR1). PARTICIPANTS, METHODS CCR1-antagonist ZK811460 was labeled with fluorine-18 to explore its possible use as specific diagnostic tool in AD. Tracer characterization comprising PET imaging of brain and metabolite analysis was performed in AD patients and controls. RESULTS Neither qualitative evaluation nor quantitative compartment analysis of PET data did show any enhanced binding of the 18F-labeled CCR1-antagonist in the brain of AD patients or controls. CONCLUSION 18F-ZK811460 did not fulfill the expectation as diagnostic tracer in PET imaging of AD.
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Affiliation(s)
- B Beuthien-Baumann
- Klinik und Poliklinik für Nuklearmedizin, Universitätsklinikum Carl Gustav Carus, Fetscherstraße 74, 01307 Dresden, Germany.
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28
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Capule CC, Yang J. Enzyme-linked immunosorbent assay-based method to quantify the association of small molecules with aggregated amyloid peptides. Anal Chem 2012; 84:1786-91. [PMID: 22243436 DOI: 10.1021/ac2030859] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
This paper describes a simple enzyme linked immunosorbent assay (ELISA) protocol for quantifying the binding of small molecules to aggregated β-amyloid (Aβ) peptides. Amyloid-targeting small molecules have attracted wide interest as potential agents for the treatment or diagnosis of neurodegenerative disorders such as Alzheimer's disease. The lack of general methods to evaluate small molecule-amyloid binding interactions, however, has significantly limited the number of amyloid-targeting molecules that have been studied to date. Here, we demonstrate a general method to quantify small molecule-amyloid binding interactions via a modified quantitative ELISA protocol. A key feature of this protocol is the treatment of commercial ELISA plates with an air plasma to help maintain the desired β-sheet content of the aggregated Aβ upon immobilization of these peptides on to the polystyrene surface. We developed an ELISA-based competition assay on these air plasma-treated plates and evaluated the binding of five previously known amyloid-binding small molecules to aggregated Aβ. We show that this general ELISA-based competition assay can be used to quantify small molecule-amyloid binding interactions in the low nanomolar to low micromolar range, which is the typical range of affinities for many amyloid-targeting diagnostic agents under current development. This simple protocol for quantifying the interaction of small molecules with aggregated Aβ peptides overcomes many limitations of previously reported spectroscopic or radioactivity assays and may, therefore, facilitate the screening and evaluation of a more structurally diverse set of amyloid-targeting agents than had previously been possible.
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Affiliation(s)
- Christina C Capule
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0358, USA
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29
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Svedberg MM, Rahman O, Hall H. Preclinical studies of potential amyloid binding PET/SPECT ligands in Alzheimer's disease. Nucl Med Biol 2012; 39:484-501. [PMID: 22226025 DOI: 10.1016/j.nucmedbio.2011.10.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Revised: 09/23/2011] [Accepted: 10/02/2011] [Indexed: 01/13/2023]
Abstract
Visualizing the neuropathological hallmarks amyloid plaques and neurofibrillary tangles of Alzheimer's disease in vivo using positron emission tomography (PET) or single photon emission computed tomography will be of great value in diagnosing the individual patient and will also help in our understanding of the disease. The successful introduction of [(11)C]PIB as a PET tracer for the amyloid plaques less than 10 years ago started an intensive research, and numerous new compounds for use in molecular imaging of the amyloid plaques have been developed. The candidates are based on dyes like thioflavin T, Congo red and chrysamine G, but also on other types such as benzoxazoles, curcumin and stilbenes. In the present review, we present methods of the radiochemistry and preclinical evaluation as well as the main properties of some of these compounds.
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Affiliation(s)
- Marie M Svedberg
- Department of Medicinal Chemistry, Preclinical PET Platform, Uppsala University, Uppsala, Sweden
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30
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Bi W, Tseng GC, Weissfeld LA, Price JC. Sparse Clustering with Resampling for Subject Classification in PET Amyloid Imaging Studies. IEEE NUCLEAR SCIENCE SYMPOSIUM CONFERENCE RECORD. NUCLEAR SCIENCE SYMPOSIUM 2011; 2011:3108-3111. [PMID: 25356069 DOI: 10.1109/nssmic.2011.6152564] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Sparse k-means clustering (Sparse_kM) can exclude uninformative variables and yield reliable parsimonious clustering results, especially for p≫n. In this work, Sparse_kM and data resampling were combined to identify variables of greatest interest and define confidence levels for the clustering. The method was evaluated by statistical simulation and applied to PiB PET amyloid imaging data to identify normal control (NC) subjects with (+) or without (-) evidence of amyloid, i.e., PiB(+/-). SIMULATIONS A dataset of n=60 observations (3 groups of 20) and p=500 variables was generated for each simulation run; only 50 variables were truly different across groups. The dataset was resampled 20 times, Sparse_kM was applied to each sample and average variable weights were calculated. Probabilities of cluster membership, also called confidence levels, were computed (n=60). Simulations were performed 250 times. The 50 truly different variables were identified by variable weights that were 13-32 times greater than those for the 450 uninformative variables. HUMAN DATA For the PiB PET dataset, images (ECAT HR+, 10-15 mCi, 90 min) were acquired for 64 cognitively normal subjects (74.1±5.4 yrs). Parametric PiB distribution volume ratio images were generated (Logan method, cerebellum reference) and normalized to the MNI template (SPM8) to produce a dataset of n=64 subjects and p=343,099 voxels/image. The dataset was resampled 10 times and Sparse_kM was applied. An average voxel weight image was computed that indicated cortical areas of greatest interest that included precuneus and frontal cortex; these are key areas linked to early amyloid deposition. Seven of 64 subjects were identified as PiB(+) and 47 as PiB(-) with confidence ≥ 90%, where another subject was PiB(+) at lower confidence (80%) and the other 9 subjects were PiB(-) at confidence in the range of 50-70%. In conclusion, Sparse_kM with resampling can help to establish confidence levels for clustering when p≫n and may be a promising method for revealing informative voxels/spatial patterns that distinguish levels of amyloid load, including that at the transitional amyloid +/- boundary.
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Affiliation(s)
- Wenzhu Bi
- Department of Biostatistics, University of Pittsburgh, Pittsburgh PA 15261 USA telephone: 412-605-1552
| | - George C Tseng
- Department of Biostatistics, University of Pittsburgh, Pittsburgh, PA, USA
| | - Lisa A Weissfeld
- Department of Biostatistics, University of Pittsburgh, Pittsburgh, PA, USA
| | - Julie C Price
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA
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32
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Gertz HJ, Kurz A. [Diagnosis without therapy: early diagnosis of Alzheimer's disease in the stage of mild cognitive impairment]. DER NERVENARZT 2011; 82:1151-9. [PMID: 21221517 DOI: 10.1007/s00115-010-3213-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Alzheimer's disease (AD) is a histopathologically defined progressive neurodegenerative disorder. Its clinical manifestation can be subdivided into the stage of mild cognitive impairment (MCI) and the stage of dementia. According to ICD-10 the diagnosis of AD can only be made in the stage of dementia. The indication for anti-dementia drugs is restricted to the stage of dementia in AD, too. Diagnostic tools to detect AD have improved considerably in recent years. They include the MRI findings of atrophy of the medial temporal lobe, cerebrospinal fluid (CSF) biomarkers β-amyloid and τ, the visualisation of metabolic deficits on positron emission tomography (PET) using [(18)F]-fluoro-2-deoxy-D-glucose (FDG) and the emerging possibility to demonstrate amyloid deposits in vivo using PET ligands. The application of these methods allows the diagnosis of AD to be established already in the stage of MCI. While diagnostic methods improve and enable us to make the diagnosis of AD very early, there is no such progress in the development of treatment options. Early diagnosis of AD appears to have benefits and drawbacks. It is most important to include the patient in the decision on early diagnosis and to make clear that there is a lack of therapeutic options if the diagnosis is positive.
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Affiliation(s)
- H-J Gertz
- Klinik und Poliklinik für Psychiatrie und Psychotherapie, Universitätsklinikum Leipzig, Semmelweisstraße 10, 04103 Leipzig, Deutschland.
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33
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Hampel H, Frank R, Broich K, Teipel SJ, Katz RG, Hardy J, Herholz K, Bokde ALW, Jessen F, Hoessler YC, Sanhai WR, Zetterberg H, Woodcock J, Blennow K. Biomarkers for Alzheimer's disease: academic, industry and regulatory perspectives. Nat Rev Drug Discov 2010; 9:560-74. [PMID: 20592748 DOI: 10.1038/nrd3115] [Citation(s) in RCA: 472] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Advances in therapeutic strategies for Alzheimer's disease that lead to even small delays in onset and progression of the condition would significantly reduce the global burden of the disease. To effectively test compounds for Alzheimer's disease and bring therapy to individuals as early as possible there is an urgent need for collaboration between academic institutions, industry and regulatory organizations for the establishment of standards and networks for the identification and qualification of biological marker candidates. Biomarkers are needed to monitor drug safety, to identify individuals who are most likely to respond to specific treatments, to stratify presymptomatic patients and to quantify the benefits of treatments. Biomarkers that achieve these characteristics should enable objective business decisions in portfolio management and facilitate regulatory approval of new therapies.
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Affiliation(s)
- Harald Hampel
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Johann Wolfgang Goethe-University, Heinrich-Hoffmann-Str. 10, 60528 Frankfurt/Main, Germany.
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34
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Vernon AC, Ballard C, Modo M. Neuroimaging for Lewy body disease: is the in vivo molecular imaging of α-synuclein neuropathology required and feasible? ACTA ACUST UNITED AC 2010; 65:28-55. [PMID: 20685363 DOI: 10.1016/j.brainresrev.2010.05.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Revised: 05/26/2010] [Accepted: 05/26/2010] [Indexed: 12/21/2022]
Abstract
Alpha-synuclein aggregation is a neuropathological hallmark of many neurodegenerative diseases including Parkinson's disease (PD), Parkinson's disease with dementia (PDD) and dementia with Lewy bodies (DLB), collectively termed the α-synucleinopathies. Substantial advances in clinical criteria and neuroimaging technology over the last 20 years have allowed great strides in the detection and differential diagnosis of these disorders. Nevertheless, it is clear that whilst the array of different imaging modalities in clinical use allow for a robust diagnosis of α-synucleinopathy in comparison to healthy subjects, there is no clear diagnostic imaging marker that affords a reliable differential diagnosis between the different forms of Lewy body disease (LBD) or that could facilitate tracking of disease progression. This has led to a call for a biomarker based on the pathological hallmarks of these diseases, namely α-synuclein-positive Lewy bodies (LBs). This potentially may be advantageous in terms of early disease detection, but may also be leveraged into a potential marker of disease progression. We here aim to firstly review the current status of neuroimaging biomarkers in PD and related synucleinopathies. Secondly, we outline the rationale behind α-synuclein imaging as a potential novel biomarker as well as the potential benefits and limitations of this approach. Thirdly, we attempt to illustrate the likely technical hurdles to be overcome to permit successful in vivo imaging of α-synuclein pathology in the diseased brain. Our overriding aim is to provide a framework for discussion of how to address this major unmet clinical need.
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Affiliation(s)
- Anthony C Vernon
- Kings College London, Institute of Psychiatry, Department of Neuroscience, Denmark Hill campus, London, UK
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Rosen RF, Ciliax BJ, Wingo TS, Gearing M, Dooyema J, Lah JJ, Ghiso JA, LeVine H, Walker LC. Deficient high-affinity binding of Pittsburgh compound B in a case of Alzheimer's disease. Acta Neuropathol 2010; 119:221-33. [PMID: 19690877 DOI: 10.1007/s00401-009-0583-3] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Revised: 08/03/2009] [Accepted: 08/05/2009] [Indexed: 11/28/2022]
Abstract
Radiolabeled Pittsburgh compound B (PIB) is a benzothiazole imaging agent that usually binds with high affinity, specificity, and stoichiometry to cerebral beta-amyloid (Abeta) in patients with Alzheimer's disease. Among a cohort of ten AD subjects examined postmortem, we describe a case of idiopathic, end-stage Alzheimer's disease with heavy Abeta deposition yet substantially diminished high-affinity binding of (3)H-PIB to cortical homogenates and unfixed cryosections. Cortical tissue samples were analyzed by immunohistochemistry, electron microscopy, ELISA, immunoblotting, MALDI-TOF mass spectrometry, in vitro (3)H-PIB binding and (3)H-PIB autoradiography. The PIB-refractory subject met the histopathological criteria for AD. However, cortical tissue from this case contained more vascular beta-amyloidosis, higher levels of insoluble Abeta40 and Abeta42, and a higher ratio of Abeta40:Abeta42 than did tissue from the nine comparison AD cases. Furthermore, cerebral Abeta from the PIB-refractory subject displayed an unusual distribution of low- and high-molecular weight Abeta oligomers, as well as a distinct pattern of N- and C-terminally truncated Abeta peptides in both the soluble and insoluble cortical extracts. Genetically, the patient was apolipoprotein-E3/4 heterozygous, and exhibited no known AD-associated mutations in the genes for the beta-amyloid precursor protein, presenilin1 or presenilin2. Our findings suggest that PIB may differentially recognize polymorphic forms of multimeric Abeta in humans with Alzheimer's disease. In addition, while the prevalence of PIB-refractory cases in the general AD population remains to be determined, the paucity of high-affinity binding sites in this AD case cautions that minimal PIB retention in positron-emission tomography scans of demented patients may not always rule out the presence of Alzheimer-type Abeta pathology.
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Affiliation(s)
- Rebecca F Rosen
- Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, USA.
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McAteer MA, Choudhury RP. Chapter 4 - Applications of nanotechnology in molecular imaging of the brain. PROGRESS IN BRAIN RESEARCH 2009; 180:72-96. [PMID: 20302829 DOI: 10.1016/s0079-6123(08)80004-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Rapid advances in the field of nanotechnology promise revolutionary improvements in the diagnosis and therapy of neuroinflammatory disorders. An array of iron oxide nano- and microparticle agents have been developed for in vivo molecular magnetic resonance imaging (mMRI) of cerebrovascular endothelial targets, such as vascular cell adhesion molecule-1 (VCAM-1), E-selectin, and the glycoprotein receptor GP IIb/IIIa expressed on activated platelets. Molecular markers of glioma cells, such as matrix metalloproteinase-2 (MMP-2), and markers for brain tumor angiogenesis, such as alpha (v) beta (3) integrin (alpha(v)beta(3)), have also been successfully targeted using nanoparticle imaging probes. This chapter provides an overview of targeted, iron oxide nano- and microparticles that have been applied for in vivo mMRI of the brain in experimental models of multiple sclerosis (MS), brain ischemia, cerebral malaria (CM), brain cancer, and Alzheimer's disease. The potential of targeted nanoparticle agents for application in clinical imaging is also discussed, including multimodal and therapeutic approaches.
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Affiliation(s)
- Martina A McAteer
- Department of Cardiovascular Medicine, John Radcliffe Hospital, Headington, Oxford, UK.
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In vitro characterisation of BF227 binding to alpha-synuclein/Lewy bodies. Eur J Pharmacol 2009; 617:54-8. [PMID: 19576880 DOI: 10.1016/j.ejphar.2009.06.042] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Revised: 06/06/2009] [Accepted: 06/22/2009] [Indexed: 11/23/2022]
Abstract
Amyloid-beta (Abeta) plaques are a pathological hallmark of Alzheimer's disease and a current target for positron emission tomography (PET) imaging agents. Whilst [(11)C]-PiB is currently the most widely used PET ligand in clinic, a novel family of benzoxazole compounds have shown promise as Abeta imaging agents; particularly BF227. We characterised the in vitro binding of [(18)F]-BF227 toward alpha-synuclein to address its selectivity for Abeta pathology, to establish whether [(18)F]-BF227 binds to alpha-synuclein/Lewy bodies, in addition to Abeta plaques. In vitro [(18)F]-BF227 saturation studies were conducted with 200 nM alpha-synuclein or Abeta(1-42) fibrils or 100 microg of Alzheimer's disease, pure dementia with Lewy bodies or control brain homogenates. Non-specific binding was established with PiB (1 microM). In vitro binding studies indicated that [(18)F]-BF227 binds with high affinity to two binding sites on Abeta(1-42) fibrils (K(D1) = 1.31 and K(D2) = 80 nM, respectively) and to one class of binding sites on alpha-synuclein fibrils (K(D) = 9.63 nM). [(18)F]-BF227 bound to Abeta-containing Alzheimer's disease brain (K(D) = 25 +/- 0.5 nM), but failed to bind to Abeta-free dementia with Lewy bodies or age-matched control homogenates. Moreover, BF227 labelled both Abeta plaques and Lewy bodies in immunohistochemical/fluorescence analysis of human Alzheimer's disease and Parkinson's disease brain sections, respectively. This study suggests that [(18)F]-BF227 is not Abeta-selective. Evaluation of BF227 as a potential biomarker for Parkinson's disease is warranted.
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Rosen RF, Walker LC, Levine H. PIB binding in aged primate brain: enrichment of high-affinity sites in humans with Alzheimer's disease. Neurobiol Aging 2009; 32:223-34. [PMID: 19329226 DOI: 10.1016/j.neurobiolaging.2009.02.011] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2008] [Revised: 02/04/2009] [Accepted: 02/10/2009] [Indexed: 10/21/2022]
Abstract
Aged nonhuman primates accumulate large amounts of human-sequence amyloid β (Aβ) in the brain, yet they do not manifest the full phenotype of Alzheimer's disease (AD). To assess the biophysical properties of Aβ that might govern its pathogenic potential in humans and nonhuman primates, we incubated the benzothiazole imaging agent Pittsburgh Compound B (PIB) with cortical tissue homogenates from normal aged humans, humans with AD, and from aged squirrel monkeys, rhesus monkeys, and chimpanzees with cerebral Aβ-amyloidosis. Relative to humans with AD, high-affinity PIB binding is markedly reduced in cortical extracts from aged nonhuman primates containing levels of insoluble Aβ similar to those in AD. The high-affinity binding of PIB may be selective for a pathologic, human-specific conformation of multimeric Aβ, and thus could be a useful experimental tool for clarifying the unique predisposition of humans to Alzheimer's disease.
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Affiliation(s)
- Rebecca F Rosen
- Division of Neuroscience, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30322, USA
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Svedberg MM, Hall H, Hellström-Lindahl E, Estrada S, Guan Z, Nordberg A, Långström B. [(11)C]PIB-amyloid binding and levels of Abeta40 and Abeta42 in postmortem brain tissue from Alzheimer patients. Neurochem Int 2008; 54:347-57. [PMID: 19162107 DOI: 10.1016/j.neuint.2008.12.016] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2008] [Revised: 12/18/2008] [Accepted: 12/22/2008] [Indexed: 11/16/2022]
Abstract
beta-Amyloid (Abeta) deposits are one of the major histopathological hallmarks of Alzheimer's disease (AD). The amyloid-imaging positron emission tomography (PET) tracer [(11)C]PIB (N-methyl[(11)C]2-(4'-methylaminophenyl)-6-hydroxy-benzothiazole) is used in the assessment of Abeta deposits in the human brain. [(11)C]PIB-amyloid interaction and insoluble Abeta40 and Abeta42 peptide levels in the brain were quantified in postmortem tissue from nine AD patients and nine age-matched control subjects in the temporal, frontal and parietal cortices and the cerebellum. Autoradiographical studies showed significantly higher densities of specific [(11)C]PIB-amyloid binding in gray matter in the temporal and parietal cortex (62fmol/mg tissue) in AD patients as compared to control subjects, whereas the density was somewhat lower in the frontal cortex (56fmol/mg tissue). No specific binding could be detected in the AD cerebellum or in the tissues from the control subjects (< or =5fmol/mg tissue). Insoluble Abeta40 and total Abeta levels (i.e. sum of Abeta40 and Abeta42) were significantly higher in patients than in controls in all measured cortical regions as determined using ELISA, which was confirmed using immunohistochemistry. The present findings show a more regional selective distribution of [(11)C]PIB amyloid binding than previously reported. Moreover, it is suggested that some of the [(11)C]PIB binding and insoluble Abeta seen in control subjects may be amyloid in the blood vessels.
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Affiliation(s)
- Marie M Svedberg
- Uppsala University, Department of Biochemistry and Organic Chemistry, Sweden.
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Abstract
Dementia of the Alzheimer type is a progressive, fatal neurodegenerative condition characterized by deterioration in cognition and memory, progressive impairment in the ability to carry out activities of daily living, and a number of neuropsychiatric symptoms. This narrative review summarizes the literature regarding descriptive epidemiology, clinical course, and characteristic neuropathological changes of dementia of the Alzheimer type. Although there are no definitive imaging or laboratory tests, except for brain biopsy, for diagnosis, brief screening instruments and neuropsychiatric test batteries used to assess the disease are discussed. Insufficient evidence exists for the use of biomarkers in clinical practice for diagnosis or disease management, but promising discoveries are summarized. Optimal treatment requires both nonpharmacological and pharmacological interventions, yet none have been shown to modify the disease's clinical course. This review describes the current available options and summarizes promising new avenues for treatment. Issues related to the care of persons with dementia of the Alzheimer type, including caregiver burden, long-term care, and the proliferation of dementia special care units, are discussed. Although advances have been made, more research is needed to address the gaps in our understanding of the disease.
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Affiliation(s)
- Jessica J Jalbert
- Department of Community Health - Epidemiology, Warren Alpert School of Medicine at Brown University, 121 South Main, Box G, Providence, RI 02912, USA.
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Ikonomovic MD, Klunk WE, Abrahamson EE, Mathis CA, Price JC, Tsopelas ND, Lopresti BJ, Ziolko S, Bi W, Paljug WR, Debnath ML, Hope CE, Isanski BA, Hamilton RL, DeKosky ST. Post-mortem correlates of in vivo PiB-PET amyloid imaging in a typical case of Alzheimer's disease. Brain 2008; 131:1630-45. [PMID: 18339640 PMCID: PMC2408940 DOI: 10.1093/brain/awn016] [Citation(s) in RCA: 664] [Impact Index Per Article: 41.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2007] [Revised: 12/29/2007] [Accepted: 01/21/2008] [Indexed: 11/13/2022] Open
Abstract
The positron emission tomography (PET) radiotracer Pittsburgh Compound-B (PiB) binds with high affinity to beta-pleated sheet aggregates of the amyloid-beta (Abeta) peptide in vitro. The in vivo retention of PiB in brains of people with Alzheimer's disease shows a regional distribution that is very similar to distribution of Abeta deposits observed post-mortem. However, the basis for regional variations in PiB binding in vivo, and the extent to which it binds to different types of Abeta-containing plaques and tau-containing neurofibrillary tangles (NFT), has not been thoroughly investigated. The present study examined 28 clinically diagnosed and autopsy-confirmed Alzheimer's disease subjects, including one Alzheimer's disease subject who had undergone PiB-PET imaging 10 months prior to death, to evaluate region- and substrate-specific binding of the highly fluorescent PiB derivative 6-CN-PiB. These data were then correlated with region-matched Abeta plaque load and peptide levels, [(3)H]PiB binding in vitro, and in vivo PET retention levels. We found that in Alzheimer's disease brain tissue sections, the preponderance of 6-CN-PiB binding is in plaques immunoreactive to either Abeta42 or Abeta40, and to vascular Abeta deposits. 6-CN-PiB labelling was most robust in compact/cored plaques in the prefrontal and temporal cortices. While diffuse plaques, including those in caudate nucleus and presubiculum, were less prominently labelled, amorphous Abeta plaques in the cerebellum were not detectable with 6-CN-PiB. Only a small subset of NFT were 6-CN-PiB positive; these resembled extracellular 'ghost' NFT. In Alzheimer's disease brain tissue homogenates, there was a direct correlation between [(3)H]PiB binding and insoluble Abeta peptide levels. In the Alzheimer's disease subject who underwent PiB-PET prior to death, in vivo PiB retention levels correlated directly with region-matched post-mortem measures of [(3)H]PiB binding, insoluble Abeta peptide levels, 6-CN-PiB- and Abeta plaque load, but not with measures of NFT. These results demonstrate, in a typical Alzheimer's disease brain, that PiB binding is highly selective for insoluble (fibrillar) Abeta deposits, and not for neurofibrillary pathology. The strong direct correlation of in vivo PiB retention with region-matched quantitative analyses of Abeta plaques in the same subject supports the validity of PiB-PET imaging as a method for in vivo evaluation of Abeta plaque burden.
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Affiliation(s)
- Milos D. Ikonomovic
- Department of Neurology, Department of Psychiatry, Department of Radiology and Department of Neuropathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
| | - William E. Klunk
- Department of Neurology, Department of Psychiatry, Department of Radiology and Department of Neuropathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
| | - Eric E. Abrahamson
- Department of Neurology, Department of Psychiatry, Department of Radiology and Department of Neuropathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
| | - Chester A. Mathis
- Department of Neurology, Department of Psychiatry, Department of Radiology and Department of Neuropathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
| | - Julie C. Price
- Department of Neurology, Department of Psychiatry, Department of Radiology and Department of Neuropathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
| | - Nicholas D. Tsopelas
- Department of Neurology, Department of Psychiatry, Department of Radiology and Department of Neuropathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
| | - Brian J. Lopresti
- Department of Neurology, Department of Psychiatry, Department of Radiology and Department of Neuropathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
| | - Scott Ziolko
- Department of Neurology, Department of Psychiatry, Department of Radiology and Department of Neuropathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
| | - Wenzhu Bi
- Department of Neurology, Department of Psychiatry, Department of Radiology and Department of Neuropathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
| | - William R. Paljug
- Department of Neurology, Department of Psychiatry, Department of Radiology and Department of Neuropathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
| | - Manik L. Debnath
- Department of Neurology, Department of Psychiatry, Department of Radiology and Department of Neuropathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
| | - Caroline E. Hope
- Department of Neurology, Department of Psychiatry, Department of Radiology and Department of Neuropathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
| | - Barbara A. Isanski
- Department of Neurology, Department of Psychiatry, Department of Radiology and Department of Neuropathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
| | - Ronald L. Hamilton
- Department of Neurology, Department of Psychiatry, Department of Radiology and Department of Neuropathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
| | - Steven T. DeKosky
- Department of Neurology, Department of Psychiatry, Department of Radiology and Department of Neuropathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
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Kumar A, Ajilore O, Kepe V, Barrio JR, Small G. Mood, cognition and in vivo protein imaging: the emerging nexus in clinical neuroscience. Int J Geriatr Psychiatry 2008; 23:555-63. [PMID: 18044797 PMCID: PMC2713874 DOI: 10.1002/gps.1941] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
INTRODUCTION Disorders of mood and cognition overlap in the elderly and there is an emerging consensus that both groups of disorders share neurobiological substrates. METHODS Salient peer reviewed articles focusing on late-life depression, structural neuroimaging and recent developments in positron emission tomography based in vivo protein imaging. RESULTS Epidemiological and clinical evidence indicates that mood and cognition in the elderly are clinically inter-related and common neurobiological mechanisms may underlie both groups of disorders. Degenerative, vascular and related mechanisms like genetically programmed abnormal protein deposition may provide the underlying neurobiological links between these disorders. CONCLUSIONS Modern neuroimaging approaches such as positron emission tomography (PET) based in vivo protein binding may help further elucidate common pathophysiological mechanisms and assist in the early identification of patients at risk for developing dementia over time. These developments have important mechanistic and public health significance in the elderly.
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Affiliation(s)
- Anand Kumar
- Department of Psychiatry, the Semel Institute for Neuroscience, University of California, Los Angeles, CA 90024, USA.
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Nathalie Lacor P. Advances on the understanding of the origins of synaptic pathology in AD. Curr Genomics 2007; 8:486-508. [PMID: 19415125 PMCID: PMC2647163 DOI: 10.2174/138920207783769530] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2007] [Revised: 12/20/2007] [Accepted: 12/20/2007] [Indexed: 12/14/2022] Open
Abstract
Although Alzheimer's disease (AD) was first discovered a century ago, we are still facing a lack of definitive diagnosis during the patient's lifetime and are unable to prescribe a curative treatment. However, the past 10 years have seen a "revamping" of the main hypothesis about AD pathogenesis and the hope to foresee possible treatment. AD is no longer considered an irreversible disease. A major refinement of the classic beta-amyloid cascade describing amyloid fibrils as neurotoxins has been made to integrate the key scientific evidences demonstrating that the first pathological event occurring in AD early stages affects synaptic function and maintenance. A concept fully compatible with synapse loss being the best pathological correlate of AD rather than other described neuropathological hallmarks (amyloid plaques, neurofibrillary tangles or neuronal death). The notion that synaptic alterations might be reverted, thus offering a potential curability, was confirmed by immunotherapy experiments targeting beta-amyloid protein in transgenic AD mice in which cognitive functions were improved despite no reduction in the amyloid plaques burden. The updated amyloid cascade now integrates the synapse failure triggered by soluble Abeta-oligomers. Still no consensus has been reached on the most toxic Abeta conformations, neither on their site of production nor on their extra- versus intra-cellular actions. Evidence shows that soluble Abeta oligomers or ADDLs bind selectively to neurons at their synaptic loci, and trigger major changes in synapse composition and morphology, which ultimately leads to dendritic spine loss. However, the exact mechanism is not yet fully understood but is suspected to involve some membrane receptor(s).
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Haier RJ, Head K, Head E, Lott IT. Neuroimaging of individuals with Down's syndrome at-risk for dementia: evidence for possible compensatory events. Neuroimage 2007; 39:1324-32. [PMID: 18006337 DOI: 10.1016/j.neuroimage.2007.09.064] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2007] [Revised: 09/20/2007] [Accepted: 09/25/2007] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND We report functional and structural brain indicators that may precede the onset of dementia in individuals with Down's syndrome (DS). METHODS Middle-aged adults with DS (n=19), a group known to be at high risk for dementia, were studied with (1) positron emission tomography (PET) to determine cerebral glucose metabolic rate (GMR), (2) structural magnetic resonance imaging (MRI) to determine gray matter volume (GM), and (3) ratings of potential dementia indicators based on a structured interview of caregiver observations designed to evaluate individuals with low intelligence. RESULTS Although none of the participants showed clinical signs of dementia, ratings of dementia indicators were correlated to both functional and structural imaging. The strongest correlations (p<.05, corrected for multiple comparisons) included the combination of higher GMR and decreased GM volume in parts of the temporal cortex, including the parahippocampus/hippocampus, in the thalamus, caudate, and frontal lobe (BA 47). INTERPRETATION The combination of increased GMR overlapping with less gray matter in these areas may be consistent with a compensatory brain response to an early stage of the disease process.
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Affiliation(s)
- R J Haier
- Department of Pediatrics, University of California, Irvine 92697-4475, USA.
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Rentz DM, Huh TJ, Sardinha LM, Moran EK, Becker JA, Daffner KR, Sperling RA, Johnson KA. Intelligence quotient-adjusted memory impairment is associated with abnormal single photon emission computed tomography perfusion. J Int Neuropsychol Soc 2007; 13:821-31. [PMID: 17697413 DOI: 10.1017/s1355617707071056] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2006] [Revised: 03/16/2007] [Accepted: 03/16/2007] [Indexed: 11/07/2022]
Abstract
Cognitive reserve among highly intelligent older individuals makes detection of early Alzheimer's disease (AD) difficult. We tested the hypothesis that mild memory impairment determined by IQ-adjusted norms is associated with single photon emission computed tomography (SPECT) perfusion abnormality at baseline and predictive of future decline. Twenty-three subjects with a Clinical Dementia Rating (CDR) score of 0, were reclassified after scores were adjusted for IQ into two groups, 10 as having mild memory impairments for ability (IQ-MI) and 13 as memory-normal (IQ-MN). Subjects underwent cognitive and functional assessments at baseline and annual follow-up for 3 years. Perfusion SPECT was acquired at baseline. At follow-up, the IQ-MI subjects demonstrated decline in memory, visuospatial processing, and phonemic fluency, and 6 of 10 had progressed to a CDR of 0.5, while the IQ-MN subjects did not show decline. The IQ-MI group had significantly lower perfusion than the IQ-MN group in parietal/precuneus, temporal, and opercular frontal regions. In contrast, higher perfusion was observed in IQ-MI compared with IQ-MN in the left medial frontal and rostral anterior cingulate regions. IQ-adjusted memory impairment in individuals with high cognitive reserve is associated with baseline SPECT abnormality in a pattern consistent with prodromal AD and predicts subsequent cognitive and functional decline.
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Affiliation(s)
- Dorene M Rentz
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
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Abstract
PURPOSE OF REVIEW This paper reviews the progress in developing amyloid imaging ligands to be used to measure amyloid in vivo in the brain of patients with Alzheimer's disease. RECENT FINDINGS Four radioligands, [18F] 1,1-dicyano-2-[6-(dimethylamino)-2-naphtalenyl] propene or 18F-FDDNP, N-methyl [11C] 2-(4'-methylaminophenyl)-6-hydroxy-benzothiasole or 11C-PIB, 4-N-methylamino-4'-hydroxystilbene [11C] or SB13 and 2-(2-[2-dimethylaminothiazol-5-yl]ethenyl)-6-(2-[fluoro]ethoxy)benzoxazole or 11C-BF-227, have so far been studied in Alzheimer's disease patients and age-matched healthy controls by PET. A robust difference was observed between PIB retention in mild patients and controls. A 2-year follow-up study in mild patients showed a stable level of PIB retention and a decrease in cerebral glucose metabolism and cognition. 18F-FDDNP showed less difference between Alzheimer's disease patients and controls compared with PIB. Both ligands have detected increases in amyloid in the brain of patients with mild cognitive impairment. SUMMARY The new PET amyloid imaging technique is a breakthrough in understanding the pathophysiological mechanisms and time course in amyloid deposits in the brain. The technique will enable early detection of Alzheimer's disease. PET amyloid imaging should be used in the evaluation of new antiamyloid therapies.
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Affiliation(s)
- Agneta Nordberg
- Karolinska Institutet, Division of Molecular Neuropharmacology, Department of Neurobiology, Care Sciences and Society, Karolinska University Hospital Huddinge, Stockholm, Sweden.
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Kandimalla KK, Wengenack TM, Curran GL, Gilles EJ, Poduslo JF. Pharmacokinetics and Amyloid Plaque Targeting Ability of a Novel Peptide-Based Magnetic Resonance Contrast Agent in Wild-Type and Alzheimer's Disease Transgenic Mice. J Pharmacol Exp Ther 2007; 322:541-9. [PMID: 17505020 DOI: 10.1124/jpet.107.119883] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A novel magnetic resonance (MR) imaging contrast agent based on a derivative of human amyloid beta (Abeta) peptide, Gd[N-4ab/Q-4ab]Abeta 30, was previously shown to cross the blood-brain barrier (BBB) and bind to amyloid plaques in Alzheimer's disease (AD) transgenic mouse (APP/PS1) brain. We now report extensive plasma and brain pharmacokinetics of this contrast agent in wild-type (WT) and in APP/PS1 mice along with a quantitative summary of various physiological factors that govern its efficacy. Upon i.v. bolus administration, (125)I-Gd[N-4ab/Q-4ab]Abeta 30 was rapidly eliminated from the plasma following a three-exponential disposition, which is saturable at higher concentrations. Nevertheless, the contrast agent exhibited rapid and nonsaturable absorption at the BBB. The brain pharmacokinetic profile of (125)I-Gd[N-4ab/Q-4ab]Abeta 30 showed a rapid absorption phase followed by a slower elimination phase. No significant differences were observed in the plasma or brain kinetics of WT and APP/PS1 animals. Emulsion autoradiography studies conducted on WT and APP/PS1 mouse brain after an i.v. bolus administration of (125)I-Gd[N-4ab/Q-4ab]Abeta 30 in vivo confirmed the brain pharmacokinetic data and also demonstrated the preferential localization of the contrast agent on the plaques for an extended period of time. These attributes of the contrast agent are extremely useful in providing an excellent signal/noise ratio during longer MR scans, which may be essential for obtaining a high resolution image. In conclusion, this study documents the successful plaque targeting of Gd[N-4ab/Q-4ab]Abeta 30 and provides crucial pharmacokinetic information to determine the dose, mode of administration, and scan times for future in vivo MR imaging of amyloid plaques in AD transgenic mice.
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Abstract
The advent of human amyloid imaging represents a research breakthrough in Alzheimer's disease (AD). It is now possible to detect the early stages of cerebral amyloidosis, a major pathologic component of AD, in living humans using positron emission tomography (PET). This technology will likely enable earlier AD diagnosis, but further research is required to determine whether a positive amyloid PET scan predicts imminent decline in questionably or mildly impaired individuals, and whether amyloid PET can be used to track the efficacy of emerging antiamyloid therapeutic agents. Initial human data are encouraging but suggest that individual amyloid PET findings should be interpreted cautiously, because cerebral amyloidosis precedes and does not equate with either clinical AD or pathologic criteria that define AD.
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Affiliation(s)
- Keith A Johnson
- Department of Radiology, Tilton 201, Massachusetts General Hospital, Boston, MA 02114, USA.
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Abstract
In sleep medicine, patients with sleep disorders are evaluated and treated. The primary assessment tool of the field has traditionally been polysomnography. While polysomnography has been helpful in the evaluation of some sleep disorders, such as sleep apnea syndrome and periodic limb movement disorder, it has been less helpful in others, such as the insomnias, or sleep disorders secondary to mental disorders. These disorders are presumed to stem from some alteration in brain function that disrupts sleep. The development of functional neuroimaging methods provides a means to understand brain function in patients with sleep disorders in a manner not accessible to polysomnography. This paper summarizes functional neuroimaging findings during healthy sleep, then, reviews available studies in sleep disorders patients, and studies addressing the pharmacology of sleep and sleep disorders. Areas in which functional neuroimaging methods may be helpful in sleep medicine, and in which future development is advised, include: (1) clarification of pathophysiology; (2) aid in differential diagnosis; (3) assessment of treatment response; (4) guiding new drug development; and (5) monitoring treatment response.
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Affiliation(s)
- Eric A Nofzinger
- Sleep Neuroimaging Research Program, Western Psychiatric Institute and Clinic, University of Pittsburgh School of Medicine, 3811 O'Hara Street, Pittsburgh, PA 15213, USA.
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50
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Harris JR. The contribution of microscopy to the study of Alzheimer's disease, amyloid plaques and Abeta fibrillogenesis. Subcell Biochem 2005; 38:1-44. [PMID: 15709471 DOI: 10.1007/0-387-23226-5_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
A broad survey is presented in this chapter, dealing with the impact that microscopy has made to the study of Alzheimer's disease, amyloid plaques and amyloid-beta fibrillogenesis. This includes classical light microscopy and the modem immunolabelling and confocal microscopies, together with the contribution of transmission electron microscopy and atomic force microscopy. Whilst usefully standing alone, the individual microscopies often contribute most effectively when they are integrated with cellular, biophysical and molecular approaches.
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Affiliation(s)
- J Robin Harris
- Institute of Zoology, University of Mainz, D-55099 Mainz, Germany
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