Roles of amyloid β-peptide-associated oxidative stress and brain protein modifications in the pathogenesis of Alzheimer's disease and mild cognitive impairment

Background: With the more widespread use of 18F-radioligand-based amyloid-β (Aβ) PET-CT imaging, we evaluated Aβ binding and the utility of neocortical 18F-Flutemetamol standardized uptake value ratio (SUVR) as a biomarker. Objective: 18F-Flutemetamol SUVR was used to differentiate 1) mild cognitive impairment (MCI) from Alzheimer’s disease (AD), and 2) MCI from other non-AD dementias (OD). Methods: 109 patients consecutively recruited from a University memory clinic underwent clinical evaluation, neuropsychological test, MRI and 18F-Flutemetamol PET-CT. The diagnosis was made by consensus of a panel consisting of 1 neuroradiologist and 2 geriatricians. The final cohort included 13 subjective cognitive decline (SCD), 22 AD, 39 MCI, and 35 OD. Quantitative analysis of 16 region-of-interests made by Cortex ID software (GE Healthcare). Results: The global mean 18F-Flutemetamol SUVR in SCD, MCI, AD, and OD were 0.50 (SD-0.08), 0.53 (SD-0.16), 0.76 (SD-0.10), and 0.56 (SD-0.16), respectively, with SUVR in SCD and MCI and OD being significantly lower than AD. Aβ binding in SCD, MCI, and OD was heterogeneous, being 23%, 38.5%, and 42.9% respectively, as compared to 100% amyloid positivity in AD. Using global SUVR, ROC analysis showed AUC of 0.868 and 0.588 in differentiating MCI from AD and MCI from OD respectively. Conclusion: 18F-Flutemetamol SUVR differentiated MCI from AD with high efficacy (high negative predictive value), but much lower efficacy from OD. The major benefit of the test was to differentiate cognitively impaired patients (either SCD, MCI, or OD) without AD-related-amyloid-pathology from AD in the clinical setting, which was under-emphasized in the current guidelines proposed by Amyloid Imaging Task Force.

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Association of brain amyloid-β with cerebral perfusion and structure in Alzheimer’s disease and mild cognitive impairment

Brain ◽

10.1093/brain/awu043 ◽

2014 ◽

Vol 137 (5) ◽

pp. 1550-1561 ◽

Cited By ~ 79

Author(s):

Niklas Mattsson ◽

Duygu Tosun ◽

Philip S. Insel ◽

Alix Simonson ◽

Clifford R Jack ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cognitive Impairment ◽

Mild Cognitive Impairment ◽

Cerebral Perfusion ◽

Amyloid Β

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[48] Amyloid β-peptide-associated free radical oxidative stress, neurotoxicity, and Alzheimer's disease

Methods in Enzymology - Amyloid, Prions, and Other Protein Aggregates ◽

10.1016/s0076-6879(99)09050-3 ◽

1999 ◽

pp. 746-768 ◽

Cited By ~ 69

Author(s):

D.Allan Butterfield ◽

Servet M. Yatin ◽

Sridhar Varadarajan ◽

Tanuja Koppal

Keyword(s):

Oxidative Stress ◽

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Free Radical ◽

Amyloid Β ◽

Amyloid Β Peptide

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The Role of Apolipoprotein E ε4 in Early and Late Mild Cognitive Impairment

European Neurology ◽

10.1159/000516774 ◽

2021 ◽

Vol 84 (6) ◽

pp. 472-480

Author(s):

Yulin Luo ◽

Li Tan ◽

Joseph Therriault ◽

Hua Zhang ◽

Ying Gao ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cognitive Impairment ◽

Mild Cognitive Impairment ◽

Apolipoprotein E ◽

Amyloid Β ◽

Disease Assessment ◽

Tau Pathology ◽

Ε4 Allele ◽

State Examination

Background: Apolipoprotein E (APOE) ε4 is highly associated with mild cognitive impairment (MCI). However, the specific influence of APOE ε4 status on tau pathology and cognitive decline in early MCI (EMCI) and late MCI (LMCI) is poorly understood. Our goal was to evaluate the association of APOE ε4 with cerebrospinal fluid (CSF) tau levels and cognition in EMCI and LMCI patients in the Alzheimer’s Disease Neuroimaging Initiative database, and whether this association was mediated by amyloid-β (Aβ). Methods: Participants were 269 cognitively normal (CN), 262 EMCI, and 344 LMCI patients. They underwent CSF Aβ42 and tau detection, APOE ε4 genotyping, Mini-Mental State Examination, (MMSE), and Alzheimer’s disease assessment scale (ADAS)-cog assessments. Linear regressions were used to examine the relation of APOE ε4 and CSF tau levels and cognitive scores in persons with and without Aβ deposition (Aβ+ and Aβ−). Results: The prevalence of APOE ε4 is higher in EMCI and LMCI than in CN (p < 0.001 for both), and in LMCI than in EMCI (p = 0.001). APOE ε4 allele was significantly higher in Aβ+ subjects than in Aβ− subjects (p < 0.001). Subjects who had a lower CSF Aβ42 level and were APOE ε4-positive experienced higher levels of CSF tau and cognitive scores in EMCI and/or LMCI. Conclusions: An APOE ε4 allele is associated with increased CSF tau and worse cognition in both EMCI and LMCI, and this association may be mediated by Aβ. We conclude that APOE ε4 may be an important mediator of tau pathology and cognition in the early stages of AD.

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Interactions between Amyloid-β and Tau in Cerebrospinal Fluid of People with Mild Cognitive Impairment and Alzheimer's Disease

Journal of Alzheimer s Disease ◽

10.3233/jad-132393 ◽

2014 ◽

Vol 42 (s3) ◽

pp. S91-S98 ◽

Cited By ~ 7

Author(s):

Zdena Kristofikova ◽

Jan Ricny ◽

Michaela Kolarova ◽

Martin Vyhnalek ◽

Jakub Hort ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cerebrospinal Fluid ◽

Cognitive Impairment ◽

Mild Cognitive Impairment ◽

Amyloid Β

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Longitudinal plasma p-tau217 is increased in early stages of Alzheimer’s disease

Brain ◽

10.1093/brain/awaa286 ◽

2020 ◽

Vol 143 (11) ◽

pp. 3234-3241 ◽

Cited By ~ 2

Author(s):

Niklas Mattsson-Carlgren ◽

Shorena Janelidze ◽

Sebastian Palmqvist ◽

Nicholas Cullen ◽

Anna L Svenningsson ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cognitive Impairment ◽

Mild Cognitive Impairment ◽

Amyloid Β ◽

Linear Mixed Effects ◽

Three Samples ◽

Longitudinal Plasma ◽

Early Alzheimer’S Disease ◽

Alzheimer’S Disease Dementia

Abstract Plasma levels of tau phosphorylated at threonine-217 (p-tau217) is a candidate tool to monitor Alzheimer’s disease. We studied 150 cognitively unimpaired participants and 100 patients with mild cognitive impairment in the Swedish BioFINDER study. P-tau217 was measured repeatedly for up to 6 years (median three samples per person, median time from first to last sample, 4.3 years). Preclinical (amyloid-β-positive cognitively unimpaired, n = 62) and prodromal (amyloid-β-positive mild cognitive impairment, n = 49) Alzheimer’s disease had accelerated p-tau217 compared to amyloid-β-negative cognitively unimpaired (β = 0.56, P < 0.001, using linear mixed effects models) and amyloid-β-negative mild cognitive impairment patients (β = 0.67, P < 0.001), respectively. Mild cognitive impairment patients who later converted to Alzheimer’s disease dementia (n = 40) had accelerated p-tau217 compared to other mild cognitive impairment patients (β = 0.79, P < 0.001). P-tau217 did not change in amyloid-β-negative participants, or in patients with mild cognitive impairment who did not convert to Alzheimer’s disease dementia. For 80% power, 109 participants per arm were required to observe a slope reduction in amyloid-β-positive cognitively unimpaired (71 participants per arm in amyloid-β-positive mild cognitive impairment). Longitudinal increases in p-tau217 correlated with longitudinal worsening of cognition and brain atrophy. In summary, plasma p-tau217 increases during early Alzheimer’s disease and can be used to monitor disease progression.

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18F-MK-6240 PET for early and late detection of neurofibrillary tangles

Brain ◽

10.1093/brain/awaa180 ◽

2020 ◽

Vol 143 (9) ◽

pp. 2818-2830 ◽

Cited By ~ 6

Author(s):

Tharick A Pascoal ◽

Joseph Therriault ◽

Andrea L Benedet ◽

Melissa Savard ◽

Firoza Z Lussier ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cognitive Impairment ◽

Mild Cognitive Impairment ◽

Amyloid Β ◽

Standardized Uptake Value ◽

Braak Staging ◽

High Affinity ◽

Tau Pet ◽

Transentorhinal Cortex

Abstract Braak stages of tau neurofibrillary tangle accumulation have been incorporated in the criteria for the neuropathological diagnosis of Alzheimer’s disease. It is expected that Braak staging using brain imaging can stratify living individuals according to their individual patterns of tau deposition, which may prove crucial for clinical trials and practice. However, previous studies using the first-generation tau PET agents have shown a low sensitivity to detect tau pathology in areas corresponding to early Braak histopathological stages (∼20% of cognitively unimpaired elderly with tau deposition in regions corresponding to Braak I–II), in contrast to ∼80–90% reported in post-mortem cohorts. Here, we tested whether the novel high affinity tau tangles tracer 18F-MK-6240 can better identify individuals in the early stages of tau accumulation. To this end, we studied 301 individuals (30 cognitively unimpaired young, 138 cognitively unimpaired elderly, 67 with mild cognitive impairment, 54 with Alzheimer’s disease dementia, and 12 with frontotemporal dementia) with amyloid-β 18F-NAV4694, tau 18F-MK-6240, MRI, and clinical assessments. 18F-MK-6240 standardized uptake value ratio images were acquired at 90–110 min after the tracer injection. 18F-MK-6240 discriminated Alzheimer’s disease dementia from mild cognitive impairment and frontotemporal dementia with high accuracy (∼85–100%). 18F-MK-6240 recapitulated topographical patterns consistent with the six hierarchical stages proposed by Braak in 98% of our population. Cognition and amyloid-β status explained most of the Braak stages variance (P < 0.0001, R2 = 0.75). No single region of interest standardized uptake value ratio accurately segregated individuals into the six topographic Braak stages. Sixty-eight per cent of the cognitively unimpaired elderly amyloid-β-positive and 37% of the cognitively unimpaired elderly amyloid-β-negative subjects displayed tau deposition, at least in the transentorhinal cortex (Braak I). Tau deposition solely in the transentorhinal cortex was associated with an elevated prevalence of amyloid-β, neurodegeneration, and cognitive impairment (P < 0.0001). 18F-MK-6240 deposition in regions corresponding to Braak IV–VI was associated with the highest prevalence of neurodegeneration, whereas in Braak V–VI regions with the highest prevalence of cognitive impairment. Our results suggest that the hierarchical six-stage Braak model using 18F-MK-6240 imaging provides an index of early and late tau accumulation as well as disease stage in preclinical and symptomatic individuals. Tau PET Braak staging using high affinity tracers has the potential to be incorporated in the diagnosis of living patients with Alzheimer’s disease in the near future.

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