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Lee C, Friedman A. Generating PET scan patterns in Alzheimer's by a mathematical model. PLoS One 2024; 19:e0299637. [PMID: 38625863 PMCID: PMC11020767 DOI: 10.1371/journal.pone.0299637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 02/13/2024] [Indexed: 04/18/2024] Open
Abstract
Alzheimer disease (AD) is the most common form of dementia. The cause of the disease is unknown, and it has no cure. Symptoms include cognitive decline, memory loss, and impairment of daily functioning. The pathological hallmarks of the disease are aggregation of plaques of amyloid-β (Aβ) and neurofibrillary tangles of tau proteins (τ), which can be detected in PET scans of the brain. The disease can remain asymptomatic for decades, while the densities of Aβ and τ continue to grow. Inflammation is considered an early event that drives the disease. In this paper, we develop a mathematical model that can produce simulated patterns of (Aβ,τ) seen in PET scans of AD patients. The model is based on the assumption that early inflammations, R and [Formula: see text], drive the growth of Aβ and τ, respectively. Recently approved drugs can slow the progression of AD in patients, provided treatment begins early, before significant damage to the brain has occurred. In line with current longitudinal studies, we used the model to demonstrate how to assess the efficacy of such drugs when given years before the disease becomes symptomatic.
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Affiliation(s)
- Chaeyoung Lee
- Department of Mathematics, Kyonggi University, Suwon, Republic of Korea
| | - Avner Friedman
- Department of Mathematics, The Ohio State University, Columbus, OH, United States of America
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Joo IL, Lam WW, Oakden W, Hill ME, Koletar MM, Morrone CD, Stanisz GJ, McLaurin J, Stefanovic B. Early alterations in brain glucose metabolism and vascular function in a transgenic rat model of Alzheimer's disease. Prog Neurobiol 2022; 217:102327. [PMID: 35870681 DOI: 10.1016/j.pneurobio.2022.102327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 05/06/2022] [Accepted: 07/18/2022] [Indexed: 11/28/2022]
Abstract
Alteration in brain metabolism predates clinical onset of Alzheimer's Disease (AD). Realizing its potential as an early diagnostic marker, however, requires understanding how early AD metabolic dysregulation manifests on non-invasive brain imaging. We presently utilized magnetic resonance imaging and spectroscopy to map glucose and ketone metabolic profiles and image cerebrovascular function in a rat model of early stage AD - 9-month-old TgF344-AD (TgAD) rats - and their age-matched non-transgenic (nTg) littermates. Compared to the nTg rats, TgAD rats displayed attenuation in global cerebral and hippocampal vasoreactivity to hypercapnia, by 49±17% and 58±19%, respectively, while their functional hyperemia to somatosensory stimulation diminished by 69±5%. To assess brain glucose uptake, rats were fasted overnight and then challenged with an intravenous infusion of 2-deoxy-D-glucose (2DG). Compared to their non-transgenic littermates, TgAD rats exhibited 99±10% and 52±5% smaller glucose uptake in the entorhinal cortex and the hippocampus, respectively. Moreover, hippocampal glucose uptake reduction in male TgAD rats compared to the nTg was 54±36% greater than the reduction seen in female TgAD rats. TgAD rats also showed a 59±42% increase in total choline level in the hippocampus, suggesting increased membrane turnover. In combination with our earlier findings of impaired electrophysiological metrics at this early stage of AD pathology progression, our findings suggest that subtle neuronal function alterations that would be difficult to assess in a clinical population may be accompanied by MRI-detectable changes in brain glucose metabolism and cerebrovascular function.
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Affiliation(s)
- Illsung L Joo
- Physical Sciences, Sunnybrook Research Institute, Toronto, ON M4N 3N5, Canada.
| | - Wilfred W Lam
- Physical Sciences, Sunnybrook Research Institute, Toronto, ON M4N 3N5, Canada.
| | - Wendy Oakden
- Physical Sciences, Sunnybrook Research Institute, Toronto, ON M4N 3N5, Canada.
| | - Mary E Hill
- Biological Sciences, Sunnybrook Research Institute, Toronto, ON M4N 3N5, Canada.
| | - Margaret M Koletar
- Physical Sciences, Sunnybrook Research Institute, Toronto, ON M4N 3N5, Canada.
| | - Christopher D Morrone
- Biological Sciences, Sunnybrook Research Institute, Toronto, ON M4N 3N5, Canada; Department of Laboratory Medicine and Pathology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada.
| | - Greg J Stanisz
- Physical Sciences, Sunnybrook Research Institute, Toronto, ON M4N 3N5, Canada; Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, ON M5G 1L7, Canada.
| | - JoAnne McLaurin
- Biological Sciences, Sunnybrook Research Institute, Toronto, ON M4N 3N5, Canada; Department of Laboratory Medicine and Pathology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada.
| | - Bojana Stefanovic
- Physical Sciences, Sunnybrook Research Institute, Toronto, ON M4N 3N5, Canada; Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, ON M5G 1L7, Canada.
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Vanhoutte M, Landeau B, Sherif S, de la Sayette V, Dautricourt S, Abbas A, Manrique A, Chocat A, Chételat G. Evaluation of the early-phase [ 18F]AV45 PET as an optimal surrogate of [ 18F]FDG PET in ageing and Alzheimer's clinical syndrome. Neuroimage Clin 2021; 31:102750. [PMID: 34247116 PMCID: PMC8274342 DOI: 10.1016/j.nicl.2021.102750] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 06/27/2021] [Accepted: 06/28/2021] [Indexed: 12/05/2022]
Abstract
Dual-phase [18F]AV45 positron emission tomography (PET) is highly promising in the assessment of neurodegenerative diseases, allowing to obtain information on both neurodegeneration (early-phase; eAV45) and amyloid deposition (late-phase; lAV45) which are highly complementary; yet eAV45 needs further evaluation. This study aims at validating eAV45 as an optimal proxy of [18F]FDG PET in a large mixed-population of healthy ageing and Alzheimer's clinical syndrome participants (n = 191) who had [18F]FDG PET, eAV45 and lAV45 scans. We found early time frame 0-4 min to give maximal correlation with [18F]FDG PET and minimal correlation with lAV45. Moreover, maximal overlap of [18F]FDG PET versus eAV45 associations with clinical diagnosis and cognition was obtained with pons scaling. Across reference regions, classification performance between clinical subgroups was similar for both eAV45 and [18F]FDG PET. These findings highlight the optimal use of eAV45 to assess neurodegeneration as a validated proxy of [18F]FDG PET. On top of this purpose, this study showed that combined [18F]AV45 PET dual-biomarker even outperformed [18F]FDG PET or lAV45 alone.
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Affiliation(s)
- Matthieu Vanhoutte
- Inserm UMR-S U1237, Caen-Normandie University, GIP Cyceron, Caen, France.
| | - Brigitte Landeau
- Inserm UMR-S U1237, Caen-Normandie University, GIP Cyceron, Caen, France
| | - Siya Sherif
- Inserm UMR-S U1237, Caen-Normandie University, GIP Cyceron, Caen, France
| | - Vincent de la Sayette
- Inserm U1077, Caen-Normandie University, École Pratique des Hautes Études, Caen, France; University Hospital, Neurology Department, Caen, France
| | - Sophie Dautricourt
- Inserm UMR-S U1237, Caen-Normandie University, GIP Cyceron, Caen, France; University Hospital, Neurology Department, Caen, France
| | - Ahmed Abbas
- Inserm U1077, Caen-Normandie University, École Pratique des Hautes Études, Caen, France
| | - Alain Manrique
- University Hospital, Nuclear Medicine Department, Caen, France
| | - Anne Chocat
- Inserm UMR-S U1237, Caen-Normandie University, GIP Cyceron, Caen, France
| | - Gaël Chételat
- Inserm UMR-S U1237, Caen-Normandie University, GIP Cyceron, Caen, France; Inserm U1077, Caen-Normandie University, École Pratique des Hautes Études, Caen, France.
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van Oostveen WM, de Lange ECM. Imaging Techniques in Alzheimer's Disease: A Review of Applications in Early Diagnosis and Longitudinal Monitoring. Int J Mol Sci 2021; 22:ijms22042110. [PMID: 33672696 PMCID: PMC7924338 DOI: 10.3390/ijms22042110] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 02/15/2021] [Accepted: 02/16/2021] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Alzheimer's disease (AD) is a progressive neurodegenerative disorder affecting many individuals worldwide with no effective treatment to date. AD is characterized by the formation of senile plaques and neurofibrillary tangles, followed by neurodegeneration, which leads to cognitive decline and eventually death. INTRODUCTION In AD, pathological changes occur many years before disease onset. Since disease-modifying therapies may be the most beneficial in the early stages of AD, biomarkers for the early diagnosis and longitudinal monitoring of disease progression are essential. Multiple imaging techniques with associated biomarkers are used to identify and monitor AD. AIM In this review, we discuss the contemporary early diagnosis and longitudinal monitoring of AD with imaging techniques regarding their diagnostic utility, benefits and limitations. Additionally, novel techniques, applications and biomarkers for AD research are assessed. FINDINGS Reduced hippocampal volume is a biomarker for neurodegeneration, but atrophy is not an AD-specific measure. Hypometabolism in temporoparietal regions is seen as a biomarker for AD. However, glucose uptake reflects astrocyte function rather than neuronal function. Amyloid-β (Aβ) is the earliest hallmark of AD and can be measured with positron emission tomography (PET), but Aβ accumulation stagnates as disease progresses. Therefore, Aβ may not be a suitable biomarker for monitoring disease progression. The measurement of tau accumulation with PET radiotracers exhibited promising results in both early diagnosis and longitudinal monitoring, but large-scale validation of these radiotracers is required. The implementation of new processing techniques, applications of other imaging techniques and novel biomarkers can contribute to understanding AD and finding a cure. CONCLUSIONS Several biomarkers are proposed for the early diagnosis and longitudinal monitoring of AD with imaging techniques, but all these biomarkers have their limitations regarding specificity, reliability and sensitivity. Future perspectives. Future research should focus on expanding the employment of imaging techniques and identifying novel biomarkers that reflect AD pathology in the earliest stages.
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Affiliation(s)
- Wieke M. van Oostveen
- Faculty of Science, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands;
| | - Elizabeth C. M. de Lange
- Division of Systems Biomedicine and Pharmacology, Leiden Academic Centre of Drug Research, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
- Correspondence: ; Tel.: +31-71-527-6330
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Shokouhi S, Riddle WR, Kang H. A new data analysis approach for measuring longitudinal changes of metabolism in cognitively normal elderly adults. Clin Interv Aging 2017; 12:2123-2130. [PMID: 29276381 PMCID: PMC5734228 DOI: 10.2147/cia.s150859] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Introduction Previously, we discussed several critical barriers in including [18F] fluorodeoxyglucose positron emission tomography ([18F]FDG-PET) imaging of preclinical Alzheimer’s disease (AD) subjects. These factors included the reference region selection and intensity normalization of PET images and the within- and across-subject variability of affected brain regions. In this study, we utilized a novel FDG-PET analysis, the regional FDG time correlation coefficient, rFTC, that can address and resolve these barriers and provide a more sensitive way of monitoring longitudinal changes in metabolism of cognitively normal elderly adults. The rFTC analysis captures the within-subject similarities between baseline and follow-up regional radiotracer distributions. Methods The rFTC trajectories of 27 cognitively normal subjects were calculated to identify 1) trajectories of rFTC decline in individual cognitively normal subjects; 2) how these trajectories correlate with the subjects’ cognitive test scores, baseline cerebrospinal fluid (CSF) levels of amyloid beta (Aβ), and apolipoprotein E4 (APOE-E4) status; and 3) whether similar trajectories are observed in regional/composite standardized uptake value ratio (SUVR) values. Results While some of the subjects maintained a stable rFTC trajectory, other subjects had declining and fluctuating rFTC values. We found that the rFTC decline was significantly higher in APOE-E4 carriers compared to noncarriers (p=0.04). We also found a marginally significant association between rFTC decline and cognitive decline measured by Alzheimer’s Disease Assessment Scale – cognitive subscale (ADAS_cog) decline (0.05). In comparison to the rFTC trajectories, the composite region of interest (ROI) SUVR trajectories did not change in any of the subjects. No individual/composite ROI SUVR changes contributed significantly to explaining changes in ADAS_cog, conversion to mild cognitive impairment (MCI), or any general changes in clinical symptoms. Conclusion The rFTC decline may serve as a new biomarker of early metabolic changes before the MCI stage.
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Affiliation(s)
- Sepideh Shokouhi
- Department of Radiology & Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - William R Riddle
- Department of Radiology & Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Hakmook Kang
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN, USA
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Moreira PI. Mini-Symposium: Energy Demand and Energy Supply in Alzheimer's Disease - Introduction. Brain Pathol 2016; 26:606. [PMID: 27327396 DOI: 10.1111/bpa.12398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 06/17/2016] [Indexed: 11/30/2022] Open
Affiliation(s)
- Paula I Moreira
- CNC-Center for Neuroscience and Cell Biology & Laboratory of Physiology, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
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