scholarly journals Recent Developments in Positron Emission Tomography Tracers for Proteinopathies Imaging in Dementia

2022 ◽  
Vol 13 ◽  
Author(s):  
Ruiqing Ni ◽  
Roger M. Nitsch

An early detection and intervention for dementia represent tremendous unmet clinical needs and priorities in society. A shared feature of neurodegenerative diseases causing dementia is the abnormal accumulation and spreading of pathological protein aggregates, which affect the selective vulnerable circuit in a disease-specific pattern. The advancement in positron emission tomography (PET) biomarkers has accelerated the understanding of the disease mechanism and development of therapeutics for Alzheimer’s disease and Parkinson’s disease. The clinical utility of amyloid-β PET and the clinical validity of tau PET as diagnostic biomarker for Alzheimer’s disease continuum have been demonstrated. The inclusion of biomarkers in the diagnostic criteria has introduced a paradigm shift that facilitated the early and differential disease diagnosis and impacted on the clinical management. Application of disease-modifying therapy likely requires screening of patients with molecular evidence of pathological accumulation and monitoring of treatment effect assisted with biomarkers. There is currently still a gap in specific 4-repeat tau imaging probes for 4-repeat tauopathies and α-synuclein imaging probes for Parkinson’s disease and dementia with Lewy body. In this review, we focused on recent development in molecular imaging biomarkers for assisting the early diagnosis of proteinopathies (i.e., amyloid-β, tau, and α-synuclein) in dementia and discussed future perspectives.

2021 ◽  
Vol 39 (3) ◽  
pp. 214-218
Author(s):  
Min Hye Kim ◽  
Joonho Lee ◽  
Hong Nam Kim ◽  
In Ja Shin ◽  
Keun Lee ◽  
...  

We report a 61-year-old woman with clinical course for Alzheimer’s disease (AD) dementia and discordant amyloid-β positron-emission tomography (PET) and cerebrospinal fluid biomarkers. Brain magnetic resonance imaging revealed remarkable atrophy in the hippocampus. However, repeated delayed <sup>18</sup>F-flutemetamol brain amyloid PET images with 1 year-interval revealed no amyloid deposition, whereas her CSF revealed low Aβ42, high total tau and p-tau181. This discordant amyloid-β PET and CSF biomarkers in this early-onset AD dementia might be associated with her low resilience or mixed pathology.


PLoS ONE ◽  
2012 ◽  
Vol 7 (12) ◽  
pp. e51958 ◽  
Author(s):  
Daniel McLean ◽  
Michael J. Cooke ◽  
Yuanfei Wang ◽  
David Green ◽  
Paul E. Fraser ◽  
...  

2020 ◽  
pp. 1-15
Author(s):  
Yaroslau Compta ◽  
Tamas Revesz

There is mounting evidence that Parkinson’s disease (PD) and Alzheimer’s disease (AD) share neuropathological hallmarks, while similar types of biomarkers are being applied to both. In this review we aimed to explore similarities and differences between PD and AD at both the neuropathology and the biomarker levels, specifically focusing on protein aggregates and synapse dysfunction. Thus, amyloid-β peptide (Aβ) and tau lesions of the Alzheimer-type are common in PD and α-synuclein Lewy-type aggregates are frequent findings in AD. Modern neuropathological techniques adding to routine immunohistochemistry might take further our knowledge of these diseases beyond protein aggregates and down to their presynaptic and postsynaptic terminals, with potential mechanistic and even future therapeutic implications. Translation of neuropathological discoveries to the clinic remains challenging. Cerebrospinal fluid (CSF) and positron emission tomography (PET) markers of Aβ and tau have been shown to be reliable for AD diagnosis. Conversely, CSF markers of α-synuclein have not been that consistent. In terms of PET markers, there is no PET probe available for α-synuclein yet, while the AD PET markers range from consistent evidence of their specificity (amyloid imaging) to greater uncertainty of their reliability due to off-target binding (tau imaging). CSF synaptic markers are attractive, still needing more evidence, which currently suggests those might be non-specific markers of disease progression. It can be summarized that there is neuropathological evidence that protein aggregates of AD and PD are present both at the soma and the synapse. Thus, a number of CSF and PET biomarkers beyond α-synuclein, tau and Aβ might capture these different faces of protein-related neurodegeneration. It remains to be seen what the longitudinal outcomes and the potential value as surrogate markers of these biomarkers are.


2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Hanna Cho ◽  
Min Seok Baek ◽  
Hye Sun Lee ◽  
Jae Hoon Lee ◽  
Young Hoon Ryu ◽  
...  

Abstract Background We aimed to investigate the clinical correlates of principal components (PCs) of tau positron emission tomography (PET) and their predictability for longitudinal changes in tau accumulation in Alzheimer’s disease (AD). Methods We enrolled 272 participants who underwent two PET scans [18F-flortaucipir for tau and 18F-florbetaben for amyloid-β (Aβ)], brain magnetic resonance imaging, and neuropsychological tests as baseline assessments. Among them, 187 participants underwent the same follow-up assessments after an average of 2 years. Using Aβ-positive AD dementia-specific PCs obtained from the baseline scans of 56 Aβ-positive patients with AD dementia, we determined the expression of the first two PCs (PC1 and PC2) in all participants. We assessed the correlation of PC expression with baseline clinical characteristics and tau accumulation rates. Moreover, we investigated the predictability of PCs for the longitudinal tau accumulation in training and test sets. Results PC1 corresponded to the tau distribution pattern in AD, while the two PC2 extremes reflected the parietal or temporal predominance of tau distribution. PC1 expression increased with tau burden and decreased with cognitive impairment, while PC2 expression decreased with advanced age and visuospatial and attention function deterioration. The tau accumulation rate was positively correlated with PC1 expression (greater tau burden) and negatively correlated with PC2 expression (temporal predominance). A regression model using both PCs could predict longitudinal changes in the tau burden (intraclass correlation coefficient = 0.775, R2 = 0.456 in test set). Conclusions PC analysis of tau PET could be useful for evaluating disease progression, characterizing the tau distribution pattern, and predicting longitudinal tau accumulation.


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