Alzheimer’s disease profiled by fluid and imaging markers: tau PET best predicts cognitive decline

AbstractFor early detection of Alzheimer’s disease, it is important to find biomarkers with predictive value for disease progression and clinical manifestations, such as cognitive decline. Individuals can now be profiled based on their biomarker status for Aβ42 (A) or tau (T) deposition and neurodegeneration (N). The aim of this study was to compare the cerebrospinal fluid (CSF) and imaging (PET/MR) biomarkers in each ATN category and to assess their ability to predict longitudinal cognitive decline. A subset of 282 patients, who had had at the same time PET investigations with amyloid-β and tau tracers, CSF sampling, and structural MRI (18% within 13 months), was selected from the ADNI dataset. The participants were grouped by clinical diagnosis at that time: cognitively normal, subjective memory concern, early or late mild cognitive impairment, or AD. Agreement between CSF (amyloid-β-1-42(A), phosphorylated-Tau181(T), total-Tau(N)), and imaging (amyloid-β PET (florbetaben and florbetapir)(A), tau PET (flortaucipir)(T), hippocampal volume (MRI)(N)) positivity in ATN was assessed with Cohen’s Kappa. Linear mixed-effects models were used to predict decline in the episodic memory. There was moderate agreement between PET and CSF for A biomarkers (Kappa = 0.39–0.71), while only fair agreement for T biomarkers (Kappa ≤ 0.40, except AD) and discordance for N biomarkers across all groups (Kappa ≤ 0.14) was found. Baseline PET tau predicted longitudinal decline in episodic memory irrespective of CSF p-Tau181 positivity (p ≤ 0.02). Baseline PET tau and amyloid-β predicted decline in episodic memory (p ≤ 0.0001), but isolated PET amyloid-β did not. Isolated PET Tau positivity was only observed in 2 participants (0.71% of the sample). While results for amyloid-β were similar using CSF or imaging, CSF and imaging results for tau and neurodegeneration were not interchangeable. PET tau positivity was superior to CSF p-Tau181 and PET amyloid-β in predicting cognitive decline in the AD continuum within 3 years of follow-up.

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Evidence of a Relation Between Hippocampal Volume, White Matter Hyperintensities, and Cognition in Subjective Cognitive Decline and Mild Cognitive Impairment

The Journals of Gerontology Series B ◽

10.1093/geronb/gbz120 ◽

2019 ◽

Vol 75 (7) ◽

pp. 1382-1392 ◽

Cited By ~ 4

Author(s):

Marie Caillaud ◽

Carol Hudon ◽

Benjamin Boller ◽

Simona Brambati ◽

Simon Duchesne ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cognitive Impairment ◽

Mild Cognitive Impairment ◽

White Matter ◽

Episodic Memory ◽

Cognitive Decline ◽

White Matter Hyperintensities ◽

Hippocampal Volume ◽

Subjective Cognitive Decline

Abstract Objective The concepts of mild cognitive impairment (MCI) and subjective cognitive decline (SCD) have been proposed to identify individuals in the early stages of Alzheimer’s disease (AD), or other neurodegenerative diseases. One approach to validate these concepts is to investigate the relationship between pathological brain markers and cognition in those individuals. Method We included 126 participants from the Consortium for the Early Identification of Alzheimer’s disease-Quebec (CIMA-Q) cohort (67 SCD, 29 MCI, and 30 cognitively healthy controls [CH]). All participants underwent a complete cognitive assessment and structural magnetic resonance imaging. Group comparisons were done using cognitive data, and then correlated with hippocampal volumes and white matter hyperintensities (WMHs). Results Significant differences were found between participants with MCI and CH on episodic and executive tasks, but no differences were found when comparing SCD and CH. Scores on episodic memory tests correlated with hippocampal volumes in both MCI and SCD, whereas performance on executive tests correlated with WMH in all of our groups. Discussion As expected, the SCD group was shown to be cognitively healthy on tasks where MCI participants showed impairment. However, SCD’s hippocampal volume related to episodic memory performances, and WMH to executive functions. Thus, SCD represents a valid research concept and should be used, alongside MCI, to better understand the preclinical/prodromal phase of AD.

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Interaction Between BDNF Val66Met and APOE4 on Biomarkers of Alzheimer’s Disease and Cognitive Decline

Journal of Alzheimer s Disease ◽

10.3233/jad-200132 ◽

2020 ◽

Vol 78 (2) ◽

pp. 721-734

Author(s):

Cynthia M. Stonnington ◽

Stefanie N. Velgos ◽

Yinghua Chen ◽

Sameena Syed ◽

Matt Huentelman ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cognitive Decline ◽

Brain Activity ◽

Amyloid Β ◽

Hippocampal Volume ◽

Rate Of Change ◽

Plaque Burden ◽

Amyloid Burden ◽

Hippocampus Volume

Background: Whether brain-derived neurotrophic factor (BDNF) Met carriage impacts the risk or progression of Alzheimer’s disease (AD) is unknown. Objective: To evaluate the interaction of BDNF Met and APOE4 carriage on cerebral metabolic rate for glucose (CMRgl), amyloid burden, hippocampus volume, and cognitive decline among cognitively unimpaired (CU) adults enrolled in the Arizona APOE cohort study. Methods: 114 CU adults (mean age 56.85 years, 38% male) with longitudinal FDG PET, magnetic resonance imaging, and cognitive measures were BDNF and APOE genotyped. A subgroup of 58 individuals also had Pittsburgh B (PiB) PET imaging. We examined baseline CMRgl, PiB PET amyloid burden, CMRgl, and hippocampus volume change over time, and rate of change in cognition over an average of 15 years. Results: Among APOE4 carriers, BDNF Met carriers had significantly increased amyloid deposition and accelerated CMRgl decline in regions typically affected by AD, but without accompanying acceleration of cognitive decline or hippocampal volume changes and with higher baseline frontal CMRgl and slower frontal decline relative to the Val/Val group. The BDNF effects were not found among APOE4 non-carriers. Conclusion: Our preliminary studies suggest that there is a weak interaction between BDNF Met and APOE4 on amyloid-β plaque burden and longitudinal PET measurements of AD-related CMRgl decline in cognitively unimpaired late-middle-aged and older adults, but with no apparent effect upon rate of cognitive decline. We suggest that cognitive effects of BDNF variants may be mitigated by compensatory increases in frontal brain activity—findings that would need to be confirmed in larger studies.

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Characterization of Alzheimer’s tau biomarker discordance using plasma, CSF, and PET

Alzheimer s Research & Therapy ◽

10.1186/s13195-021-00834-3 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Yu Guo ◽

◽

Yu-Yuan Huang ◽

Xue-Ning Shen ◽

Shi-Dong Chen ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cognitive Decline ◽

Amyloid Β ◽

Regions Of Interest ◽

Emission Tomography ◽

Braak Stage ◽

Positron Emission ◽

Tau Pet

Abstract Background We aimed to investigate the tau biomarker discrepancies of Alzheimer’s disease (AD) using plasma tau phosphorylated at threonine 181 (p-tau181), cerebrospinal fluid (CSF) p-tau181, and AV1451 positron emission tomography (PET). Methods In the Alzheimer’s Disease Neuroimaging Initiative, 724 non-demented participants were categorized into plasma/CSF and plasma/PET groups. Demographic and clinical variables, amyloid-β (Aβ) burden, flortaucipir-PET binding in Braak regions of interest (ROIs), longitudinal changes in clinical outcomes, and conversion risk were compared. Results Across different tau biomarker groups, the proportion of participants with a discordant profile varied (plasma+/CSF− 15.6%, plasma−/CSF+ 15.3%, plasma+/PET− 22.4%, and plasma−/PET+ 6.1%). Within the plasma/CSF categories, we found an increase from concordant-negative to discordant to concordant-positive in the frequency of Aβ pathology or cognitive impairment, rates of cognitive decline, and risk of cognitive conversion. However, the two discordant categories (plasma+/CSF− and plasma−/CSF+) showed comparable performances, resulting in similarly reduced cognitive capacities. Regarding plasma/PET categories, as expected, PET-positive individuals had increased Aβ burden, elevated flortaucipir retention in Braak ROIs, and accelerated cognitive deterioration than concordant-negative persons. Noteworthy, discordant participants with normal PET exhibited reduced flortaucipir uptake in Braak stage ROIs and slower rates of cognitive decline, relative to those PET-positive. Therefore, individuals with PET abnormality appeared to have advanced tau pathological changes and poorer cognitive function, regardless of the plasma status. Furthermore, these results were found only in individuals with Aβ pathology. Conclusions Our results indicate that plasma and CSF p-tau181 abnormalities associated with amyloidosis occur simultaneously in the progression of AD pathogenesis and related cognitive decline, before tau-PET turns positive.

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PET Amyloid and Tau Status Are Differently Affected by Patient Features

Journal of Alzheimer s Disease ◽

10.3233/jad-200124 ◽

2020 ◽

Vol 78 (3) ◽

pp. 1129-1136

Author(s):

Meng-Shan Tan ◽

Yu-Xiang Yang ◽

Hui-Fu Wang ◽

Wei Xu ◽

Chen-Chen Tan ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Amyloid Β ◽

Amyloid Pet ◽

Tau Pathology ◽

Clinical Genetic ◽

Multivariable Logistic Regression Model ◽

Tau Pet ◽

Pet Amyloid

Background: Amyloid-β (Aβ) plaques and tau neurofibrillary tangles are two neuropathological hallmarks of Alzheimer’s disease (AD), which both can be visualized in vivo using PET radiotracers, opening new opportunities to study disease mechanisms. Objective: Our study investigated 11 non-PET factors in 5 categories (including demographic, clinical, genetic, MRI, and cerebrospinal fluid (CSF) features) possibly affecting PET amyloid and tau status to explore the relationships between amyloid and tau pathology, and whether these features had a different association with amyloid and tau status. Methods: We included 372 nondemented elderly from the Alzheimer’s Disease Neuroimaging Initiative cohort. All underwent PET amyloid and tau analysis simultaneously, and were grouped into amyloid/tau quadrants based on previously established abnormality cut points. We examined the associations of above selected features with PET amyloid and tau status using a multivariable logistic regression model, then explored whether there was an obvious correlation between the significant features and PET amyloid or tau levels. Results: Our results demonstrated that PET amyloid and tau status were differently affected by patient features, and CSF biomarker features provided most significant values associating PET findings. CSF Aβ42/40 was the most important factor affecting amyloid PET status, and negatively correlated with amyloid PET levels. CSF pTau could significantly influence both amyloid and tau PET status. Besides CSF pTau and Aβ42, APOE ɛ4 allele status and Mini-Mental State Examination scores also could influence tau PET status, and significantly correlated with tau PET levels. Conclusion: Our results support that tau pathology possibly affected by Aβ-independent factors, implicating the importance of tau pathology in AD pathogenesis.

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Age, vascular disease, and Alzheimer’s disease pathologies in amyloid negative elderly adults

Alzheimer s Research & Therapy ◽

10.1186/s13195-021-00913-5 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Tengfei Guo ◽

Susan M. Landau ◽

William J. Jagust ◽

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cognitive Decline ◽

Fdg Pet ◽

Amyloid Β ◽

Hippocampal Volume ◽

Factors Associated ◽

Male Sex ◽

The Relationship

Abstract Background We recently reported that CSF phosphorylated tau (p-Tau181) relative to Aβ40 (CSF p-Tau/Aβ40 ratio) was less noisy and increased associations with Alzheimer’s disease (AD) biomarkers compared to CSF p-Tau181 alone. While elevations of CSF p-Tau/Aβ40 can occur in amyloid-β (Aβ) negative (Aβ-) individuals, the factors associated with these elevations and their role in neurodegeneration and cognitive decline are unknown. We aim to explore factors associated with elevated tau in CSF, and how these elevated tau are related to neurodegeneration and cognitive decline in the absence of Aβ positivity. Methods We examined relationships between CSF p-Tau/Aβ40, and CSF Aβ42/Aβ40, Aβ PET, and white matter hyperintensities (WMH) as well as vascular risk factors in 149 cognitively unimpaired and 52 impaired individuals who were presumably not on the Alzheimer’s disease (AD) pathway due to negative Aβ status on both CSF and PET. Subgroups had 18F-fluorodeoxyglucose (FDG) PET and adjusted hippocampal volume (aHCV), and longitudinal measures of CSF, aHCV, FDG PET, and cognition data, so we examined CSF p-Tau/Aβ40 associations with these measures as well. Results Elevated CSF p-Tau/Aβ40 was associated with older age, male sex, greater WMH, and hypertension as well as a pattern of hippocampal atrophy and temporoparietal hypometabolism characteristic of AD. Lower CSF Aβ42/Aβ40, higher WMH, and hypertension but not age, sex, Aβ PET, APOE-ε4 status, body mass index, smoking, and hyperlipidemia at baseline predicted CSF p-Tau/Aβ40 increases over approximately 5 years of follow-up. The relationship between CSF p-Tau/Aβ40 and subsequent cognitive decline was partially or fully explained by neurodegenerative measurements. Conclusions These data provide surprising clues as to the etiology and significance of tau pathology in the absence of Aβ. It seems likely that, in addition to age, both cerebrovascular disease and subthreshold levels of Aβ are related to this tau accumulation. Crucially, this phenotype of CSF tau elevation in amyloid-negative individuals share features with AD such as a pattern of metabolic decline and regional brain atrophy.

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Pharmacogenetics of Angiotensin-Converting Enzyme Inhibitors in Patients with Alzheimer's Disease Dementia

Current Alzheimer Research ◽

10.2174/1567205014666171016101816 ◽

2018 ◽

Vol 15 (4) ◽

pp. 386-398 ◽

Cited By ~ 22

Author(s):

Fabricio Ferreira de Oliveira ◽

Elizabeth Suchi Chen ◽

Marilia Cardoso Smith ◽

Paulo Henrique Ferreira Bertolucci

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Angiotensin Converting Enzyme ◽

Cognitive Decline ◽

Enzyme Inhibitors ◽

Late Onset ◽

Amyloid Β ◽

Converting Enzyme ◽

Converting Enzyme Inhibitors ◽

Alzheimer’S Disease Dementia

Background: While the angiotensin-converting enzyme degrades amyloid-β, angiotensinconverting enzyme inhibitors (ACEis) may slow cognitive decline by way of cholinergic effects, by increasing brain substance P and boosting the activity of neprilysin, and by modulating glucose homeostasis and augmenting the secretion of adipokines to enhance insulin sensitivity in patients with Alzheimer’s disease dementia (AD). We aimed to investigate whether ACE gene polymorphisms rs1800764 and rs4291 are associated with cognitive and functional change in patients with AD, while also taking APOE haplotypes and anti-hypertensive treatment with ACEis into account for stratification. Methods: Consecutive late-onset AD patients were screened with cognitive tests, while their caregivers were queried for functional and caregiver burden scores. Prospective pharmacogenetic correlations were estimated for one year, considering APOE and ACE genotypes and haplotypes, and treatment with ACEis. Results: For 193 patients, minor allele frequencies were 0.497 for rs1800764 – C (44.6% heterozygotes) and 0.345 for rs4291 – T (38.9% heterozygotes), both in Hardy-Weinberg equilibrium. Almost 94% of all patients used cholinesterase inhibitors, while 155 (80.3%) had arterial hypertension, and 124 used ACEis. No functional impacts were found regarding any genotypes or pharmacological treatment. Either for carriers of ACE haplotypes that included rs1800764 – T and rs4291 – A, or for APOE4- carriers of rs1800764 – T or rs4291 – T, ACEis slowed cognitive decline independently of blood pressure variations. APOE4+ carriers were not responsive to treatment with ACEis. Conclusion: ACEis may slow cognitive decline for patients with AD, more remarkably for APOE4- carriers of specific ACE genotypes.

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24(S)-Saringosterol Prevents Cognitive Decline in a Mouse Model for Alzheimer’s Disease

Marine Drugs ◽

10.3390/md19040190 ◽

2021 ◽

Vol 19 (4) ◽

pp. 190

Author(s):

Nikita Martens ◽

Melissa Schepers ◽

Na Zhan ◽

Frank Leijten ◽

Gardi Voortman ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Mouse Model ◽

Cognitive Decline ◽

Inflammatory Marker ◽

Amyloid Β ◽

Liver Fat ◽

Gas Chromatography Mass Spectrometry ◽

Memory Decline ◽

Plaque Load

We recently found that dietary supplementation with the seaweed Sargassum fusiforme, containing the preferential LXRβ-agonist 24(S)-saringosterol, prevented memory decline and reduced amyloid-β (Aβ) deposition in an Alzheimer’s disease (AD) mouse model without inducing hepatic steatosis. Here, we examined the effects of 24(S)-saringosterol as a food additive on cognition and neuropathology in AD mice. Six-month-old male APPswePS1ΔE9 mice and wildtype C57BL/6J littermates received 24(S)-saringosterol (0.5 mg/25 g body weight/day) (APPswePS1ΔE9 n = 20; C57BL/6J n = 19) or vehicle (APPswePS1ΔE9 n = 17; C57BL/6J n = 19) for 10 weeks. Cognition was assessed using object recognition and object location tasks. Sterols were analyzed by gas chromatography/mass spectrometry, Aβ and inflammatory markers by immunohistochemistry, and gene expression by quantitative real-time PCR. Hepatic lipids were quantified after Oil-Red-O staining. Administration of 24(S)-saringosterol prevented cognitive decline in APPswePS1ΔE9 mice without affecting the Aβ plaque load. Moreover, 24(S)-saringosterol prevented the increase in the inflammatory marker Iba1 in the cortex of APPswePS1ΔE9 mice (p < 0.001). Furthermore, 24(S)-saringosterol did not affect the expression of lipid metabolism-related LXR-response genes in the hippocampus nor the hepatic neutral lipid content. Thus, administration of 24(S)-saringosterol prevented cognitive decline in APPswePS1ΔE9 mice independent of effects on Aβ load and without adverse effects on liver fat content. The anti-inflammatory effects of 24(S)-saringosterol may contribute to the prevention of cognitive decline.

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Elevated basal cortisol level predicts lower hippocampal volume and cognitive decline in Alzheimer’s disease

Journal of Clinical Neuroscience ◽

10.1016/j.jocn.2008.12.026 ◽

2009 ◽

Vol 16 (10) ◽

pp. 1283-1286 ◽

Cited By ~ 73

Author(s):

Chi-Wei Huang ◽

Chun-Chung Lui ◽

Weng-Neng Chang ◽

Cheng-Hsien Lu ◽

Ya-Ling Wang ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cognitive Decline ◽

Cortisol Level ◽

Hippocampal Volume ◽

Basal Cortisol ◽

Basal Cortisol Level

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Gestational Stress Augments Postpartum β-Amyloid Pathology and Cognitive Decline in a Mouse Model of Alzheimer’s Disease

Cerebral Cortex ◽

10.1093/cercor/bhy251 ◽

2018 ◽

Vol 29 (9) ◽

pp. 3712-3724 ◽

Cited By ~ 5

Author(s):

Zahra Jafari ◽

Jogender Mehla ◽

Bryan E Kolb ◽

Majid H Mohajerani

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Risk Factor ◽

Cognitive Decline ◽

Noise Exposure ◽

Amyloid Β ◽

Control Group ◽

Plaque Size ◽

Model Of Alzheimer’S Disease ◽

Gestational Stress

Abstract Besides well-known risk factors for Alzheimer’s disease (AD), stress, and in particular noise stress (NS), is a lifestyle risk factor common today. It is known that females are at a significantly greater risk of developing AD than males, and given that stress is a common adversity in females during pregnancy, we hypothesized that gestational noise exposure could exacerbate the postpartum development of the AD-like neuropathological changes during the life span. Pregnant APPNL-G-F/NL-G-F mice were randomly assigned to either the stress condition or control group. The stress group was exposed to the NS on gestational days 12–16, which resulted in a markedly higher hypothalamic–pituitary–adrenal (HPA) axis responsivity during the postpartum stage. Higher amyloid-β (Aβ) deposition and larger Aβ plaque size in the olfactory area were the early onset impacts of the gestational stress (GS) seen at the age of 4 months. This pattern of increased Aβ aggregation and larger plaque size were observed in various brain areas involved in both AD and stress regulation, especially in limbic structures, at the age of 6 months. The GS also produced anxiety-like behavior, deficits in learning and memory, and impaired motor coordination. The findings suggest that environmental stresses during pregnancy pose a potential risk factor in accelerating postpartum cognitive decline and AD-like neuropathological changes in the dams (mothers) later in life.

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Neurophysiological signatures in Alzheimer’s disease are distinctly associated with TAU, amyloid-β accumulation, and cognitive decline

Science Translational Medicine ◽

10.1126/scitranslmed.aaz4069 ◽

2020 ◽

Vol 12 (534) ◽

pp. eaaz4069 ◽

Cited By ~ 5

Author(s):

Kamalini G. Ranasinghe ◽

Jungho Cha ◽

Leonardo Iaccarino ◽

Leighton B. Hinkley ◽

Alexander J. Beagle ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cognitive Decline ◽

Amyloid Β ◽

Tracer Uptake ◽

Therapeutic Approaches ◽

Regional Patterns ◽

Positron Emission ◽

Network Synchrony ◽

Network Disruptions

Neural synchrony is intricately balanced in the normal resting brain but becomes altered in Alzheimer’s disease (AD). To determine the neurophysiological manifestations associated with molecular biomarkers of AD neuropathology, in patients with AD, we used magnetoencephalographic imaging (MEGI) and positron emission tomography with amyloid-beta (Aβ) and TAU tracers. We found that alpha oscillations (8 to 12 Hz) were hyposynchronous in occipital and posterior temporoparietal cortices, whereas delta-theta oscillations (2 to 8 Hz) were hypersynchronous in frontal and anterior temporoparietal cortices, in patients with AD compared to age-matched controls. Regional patterns of alpha hyposynchrony were unique in each neurobehavioral phenotype of AD, whereas the regional patterns of delta-theta hypersynchrony were similar across the phenotypes. Alpha hyposynchrony strongly colocalized with TAU deposition and was modulated by the degree of TAU tracer uptake. In contrast, delta-theta hypersynchrony colocalized with both TAU and Aβ depositions and was modulated by both TAU and Aβ tracer uptake. Furthermore, alpha hyposynchrony but not delta-theta hypersynchrony was correlated with the degree of global cognitive dysfunction in patients with AD. The current study demonstrates frequency-specific neurophysiological signatures of AD pathophysiology and suggests that neurophysiological measures from MEGI are sensitive indices of network disruptions mediated by TAU and Aβ and associated cognitive decline. These findings facilitate the pursuit of novel therapeutic approaches toward normalizing network synchrony in AD.

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