scholarly journals Contribution of genetic and environmental factors to the onset of preclinical Alzheimer’s disease - a monozygotic twin study

2020 ◽  
Author(s):  
Elles Konijnenberg ◽  
Jori Tomassen ◽  
Anouk den Braber ◽  
Mara ten Kate ◽  
Maqsood M. Yaqub ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Environmental Factors ◽  
Random Effect ◽  
Monozygotic Twin ◽  
Amyloid Pet ◽  
Positron Emission ◽  
Aβ Aggregation ◽  
T Tau ◽  
Aβ Production

AbstractObjectiveTo study the genetic contribution to the start of Alzheimer’s disease as signified by abnormalities in amyloid and tau biomarkers in cognitively intact older identical twins.MethodsWe studied in 96 monozygotic twin-pairs relationships between Aβ aggregation as measured by the ratio Aβ1-42/1-40 in cerebrospinal fluid (CSF) and positron emission tomography (PET), and CSF markers for Aβ production (BACE1, Aβ1-40 and 1-38) and tau. Associations amongst markers were tested with Generalized Estimating Equations including a random effect for twin status, adjusted for age, gender, and APOE ε4 genotype. We used twin analyses to determine relative contributions of genetic and/or environmental factors to AD pathophysiological processes.ResultsTwenty-seven individuals (14%) had an abnormal amyloid-PET, and 14 twin-pairs (15%) showed discordant amyloid status. Within twin-pairs, Aβ production markers and total-tau (t-tau) levels strongly correlated (r range 0.76, 0.88; all p<0.0001), and Aβ aggregation markers and 181-phosphorylated-tau (p-tau) levels correlated moderately strong (r range 0.49, 0.52; all p<0.0001). Cross-twin cross-trait analysis showed that Aβ1-38 in one twin correlated with Aβ1-42/1-40 ratios, t-tau and p-tau levels in their co-twins (r range 0.18, 0.58; all p<.07). Within-pair differences in Aβ production markers related to differences in tau levels (r range 0.49, 0.61; all p<0.0001). Twin discordance analyses suggest that Aβ production and tau levels show coordinated increases in very early AD.InterpretationOur results suggest a substantial genetic/shared environmental background contributes to both Aβ and tau increases, suggesting that modulation of environmental risk factors may aid in delaying the onset of AD pathophysiological processes.

scholarly journals Aβ deposition is associated with increases in soluble and phosphorylated tau that precede a positive Tau PET in Alzheimer’s disease

2020 ◽  
Vol 6 (16) ◽  
pp. eaaz2387 ◽  
Author(s):  
Niklas Mattsson-Carlgren ◽  
Emelie Andersson ◽  
Shorena Janelidze ◽  
Rik Ossenkoppele ◽  
Philip Insel ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Amyloid Pet ◽  
Phosphorylated Tau ◽  
Positron Emission ◽  
Aβ Aggregation ◽  
Tau Pet ◽  
5Xfad Mice ◽  
Tau Aggregation ◽  
T Tau

The links between β-amyloid (Aβ) and tau in Alzheimer’s disease are unclear. Cognitively unimpaired persons with signs of Aβ pathology had increased cerebrospinal fluid (CSF) phosphorylated tau (P-tau181 and P-tau217) and total-tau (T-tau), which increased over time, despite no detection of insoluble tau aggregates [normal Tau positron emission tomography (PET)]. CSF P-tau and T-tau started to increase before the threshold for Amyloid PET positivity, while Tau PET started to increase after Amyloid PET positivity. Effects of Amyloid PET on Tau PET were mediated by CSF P-tau, and high CSF P-tau predicted increased Tau PET rates. Individuals with MAPT mutations and signs of tau deposition (but without Aβ pathology) had normal CSF P-tau levels. In 5xFAD mice, CSF tau increased when Aβ aggregation started. These results show that Aβ pathology may induce changes in soluble tau release and phosphorylation, which is followed by tau aggregation several years later in humans.

A Japanese Multicenter Study on PET and Other Biomarkers for Subjects with Potential Preclinical and Prodromal Alzheimer’s Disease

2021 ◽  
pp. 1-8
Author(s):  
M. Senda ◽  
K. Ishii ◽  
K. Ito ◽  
T. Ikeuchi ◽  
H. Matsuda ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cognitive Impairment ◽  
Multicenter Study ◽  
Fdg Pet ◽  
Structural Mri ◽  
Amyloid Pet ◽  
Positron Emission ◽  
Prodromal Alzheimer’S Disease ◽  
T Tau

BACKGROUND: PET (positron emission tomography) and CSF (cerebrospinal fluid) provide the “ATN” (Amyloid, Tau, Neurodegeneration) classification and play an essential role in early and differential diagnosis of Alzheimer’s disease (AD). OBJECTIVE: Biomarkers were evaluated in a Japanese multicenter study on cognitively unimpaired subjects (CU) and early (E) and late (L) mild cognitive impairment (MCI) patients. MEASUREMENTS: A total of 38 (26 CU, 7 EMCI, 5 LMCI) subjects with the age of 65-84 were enrolled. Amyloid-PET and FDG-PET as well as structural MRI were acquired on all of them, with an additional tau-PET with 18F-flortaucipir on 15 and CSF measurement of Aβ1-42, P-tau, and T-tau on 18 subjects. Positivity of amyloid and tau was determined based on the positive result of either PET or CSF. RESULTS: The amyloid positivity was 13/38, with discordance between PET and CSF in 6/18. Cortical tau deposition quantified with PET was significantly correlated with CSF P-tau, in spite of discordance in the binary positivity between visual PET interpretation and CSF P-tau in 5/8 (PET-/CSF+). Tau was positive in 7/9 amyloid positive and 8/16 amyloid negative subjects who underwent tau measurement, respectively. Overall, a large number of subjects presented quantitative measures and/or visual read that are close to the borderline of binary positivity, which caused, at least partly, the discordance between PET and CSF in amyloid and/or tau. Nine subjects presented either tau or FDG-PET positive while amyloid was negative, suggesting the possibility of non-AD disorders. CONCLUSION: Positivity rate of amyloid and tau, together with their relationship, was consistent with previous reports. Multicenter study on subjects with very mild or no cognitive impairment may need refining the positivity criteria and cutoff level as well as strict quality control of the measurements.

scholarly journals Prospective longitudinal atrophy in Alzheimer’s disease correlates with the intensity and topography of baseline tau-PET

2020 ◽  
Vol 12 (524) ◽  
pp. eaau5732 ◽  
Author(s):  
Renaud La Joie ◽  
Adrienne V. Visani ◽  
Suzanne L. Baker ◽  
Jesse A. Brown ◽  
Viktoriya Bourakova ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Amyloid Pet ◽  
Specific Distribution ◽  
Positron Emission ◽  
Pet Radiotracers ◽  
Β Amyloid ◽  
Tau Pet ◽  
Prospective Longitudinal

β-Amyloid plaques and tau-containing neurofibrillary tangles are the two neuropathological hallmarks of Alzheimer’s disease (AD) and are thought to play crucial roles in a neurodegenerative cascade leading to dementia. Both lesions can now be visualized in vivo using positron emission tomography (PET) radiotracers, opening new opportunities to study disease mechanisms and improve patients’ diagnostic and prognostic evaluation. In a group of 32 patients at early symptomatic AD stages, we tested whether β-amyloid and tau-PET could predict subsequent brain atrophy measured using longitudinal magnetic resonance imaging acquired at the time of PET and 15 months later. Quantitative analyses showed that the global intensity of tau-PET, but not β-amyloid–PET, signal predicted the rate of subsequent atrophy, independent of baseline cortical thickness. Additional investigations demonstrated that the specific distribution of tau-PET signal was a strong indicator of the topography of future atrophy at the single patient level and that the relationship between baseline tau-PET and subsequent atrophy was particularly strong in younger patients. These data support disease models in which tau pathology is a major driver of local neurodegeneration and highlight the relevance of tau-PET as a precision medicine tool to help predict individual patient’s progression and design future clinical trials.

scholarly journals Efficacy and Limitations of rCBF-SPECT in the Diagnosis of Alzheimer’s Disease With Amyloid-PET

2019 ◽  
Vol 34 (5) ◽  
pp. 314-321
Author(s):  
Miwako Takahashi ◽  
Tomoko Tada ◽  
Tomomi Nakamura ◽  
Keitaro Koyama ◽  
Toshimitsu Momose
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Rating Scale ◽  
Single Photon ◽  
Photon Emission ◽  
Emission Computed Tomography ◽  
Amyloid Pet ◽  
Clinical Dementia Rating ◽  
Positron Emission ◽  
Rcbf Spect

This study aimed to assess efficacy and limitations of regional cerebral blood flow imaging using single-photon emission computed tomography (rCBF-SPECT) in the diagnosis of Alzheimer’s disease (AD) with amyloid-positron emission tomography (amyloid-PET). Thirteen patients, who underwent both rCBF-SPECT and amyloid-PET after clinical diagnosis of AD or mild cognitive impairment, were retrospectively identified. The rCBF-SPECTs were classified into 4 grades, from typical AD pattern to no AD pattern of hypoperfusion; amyloid-beta (Aβ) positivity was assessed by amyloid-PET. Four patients were categorized into a typical AD pattern on rCBF-SPECT, and all were Aβ+. The other 9 patients did not exhibit a typical AD pattern; however, 4 were Aβ+. The Mini-Mental State Examination score and Clinical Dementia Rating scale were not significantly different between Aβ+ and Aβ– patients. A typical AD pattern on rCBF-SPECT can reflect Aβ+; however, if not, rCBF-SPECT has a limitation to predict amyloid pathology.

Amyloid imaging in Alzheimer’s disease: a potential new era of personalized medicine?

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Antoine Leuzy ◽  
Eduardo Zimmer ◽  
Serge Gauthier ◽  
Pedro Rosa-Neto
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Personalized Medicine ◽  
Amyloid Imaging ◽  
Phase Iii ◽  
Diagnostic Process ◽  
European Medicines Agency ◽  
Amyloid Pet ◽  
Positron Emission

AbstractRecent advances along clinical and neuropathological lines, as well as in our ability to detect the deposition of β-amyloid (Aβ) in vivo using positron emission tomography (PET), have helped redefine Alzheimer’s disease (AD) as a dynamic clinicobiological entity. On the basis of these advances, AD is now conceptualized as a continuum comprising asymptomatic, minimally symptomatic, and dementia phases, with detection of brain Aβ — in particular, via PET amyloid imaging — central to the diagnostic process. In this respect, [18F]florbetapir (Amyvid™) and [18F]flutemetamol (Vizamyl™) have recently received approval for clinical use from the Food and Drug Administration (FDA) and the European Medicines Agency (EMA), with additional radiofluorinated tracers for detection of Aβ in phase III trials. Recent initiatives such as the Alzheimer’s Disease Neuroimaging Initiative (ADNI) suggest that Aβ production, oligomerization and aggregation begins many years, possibly decades, before detectable cognitive impairment, with Aβ shown to associate with cognitive decline and conversion to dementia. While personalized medicine has now emerged as a prospect for the field, the recent decision by the Centers for Medicare & Medicaid Services (CMS) — who declined to cover the cost of amyloid PET imaging citing insufficient evidence to support its clinical utility — highlights that such a move may be premature.

scholarly journals The Challenges of Diagnosis in Alzheimer’s Disease

US Neurology ◽  
2018 ◽  
Vol 14 (1) ◽  
pp. 15 ◽  
Author(s):  
Nenad Bogdanovic
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Amyloid Beta ◽  
Amyloid Pet ◽  
Positive Finding ◽  
Positron Emission ◽  
University Of Oslo ◽  
The University ◽  
Study Participants ◽  
The Brain

Current neuropathologic examination of the brain is still the gold standard for diagnosis of Alzheimer’s disease (AD). Postmortem studies, however, have indicated that current methods for the clinical diagnosis of AD are suboptimal.1Recent research has demonstrated the clinical utility of amyloid-beta positron emission tomography (PET) scans, which detect the presence of amyloid-beta plaques in the brain. In a study presented at the Alzheimer’s Association International Conference (AAIC) in London, UK, July 2017, by Nenad Bogdanovic, MD, PhD, of the University of Oslo in Norway, amyloid PET imaging was found to be a fundamental diagnostic tool for AD, establishing a definite diagnosis or excluding AD in all 50 study participants.2 The use of cerebrospinal fluid (CSF) amyloid testing with a higher amyloid-beta plaque threshold than that traditionally used to establish a positive finding also resulted in high diagnostic accuracy, resulting in diagnosis or exclusion in 44 of 50 participants (88%) compared with only 21 individuals (42%) using traditional cutoffs.2

scholarly journals Longitudinal Observation of Early-Onset Alzheimer’s Disease Dementia with Positive CSF Biomarkers/Negative Amyloid-β Positron-Emission Tomography

2021 ◽  
Vol 39 (3) ◽  
pp. 214-218
Author(s):  
Min Hye Kim ◽  
Joonho Lee ◽  
Hong Nam Kim ◽  
In Ja Shin ◽  
Keun Lee ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Positron Emission Tomography ◽  
Early Onset ◽  
Brain Magnetic Resonance Imaging ◽  
Amyloid Β ◽  
Emission Tomography ◽  
Csf Biomarkers ◽  
Amyloid Pet ◽  
Positron Emission

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.

scholarly journals Associations of Fully Automated CSF and Novel Plasma Biomarkers With Alzheimer Disease Neuropathology at Autopsy

Neurology ◽  
2021 ◽  
pp. 10.1212/WNL.0000000000012513
Author(s):  
Michel J. Grothe ◽  
Alexis Moscoso ◽  
Nicholas J. Ashton ◽  
Thomas K. Karikari ◽  
Juan Lantero-Rodriguez ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Csf Biomarkers ◽  
Amyloid Pet ◽  
Braak Stage ◽  
Neuritic Plaques ◽  
Neurofilament Light ◽  
T Tau

Objective:To study cerebrospinal fluid (CSF) biomarkers of Alzheimer’s disease (AD) analyzed by fully automated Elecsys immunoassays in comparison to neuropathologic gold standards, and compare their accuracy to plasma phosphorylated tau (p-tau181) measured using a novel Simoa method.Methods:We studied ante-mortem Elecsys-derived CSF biomarkers in 45 individuals who underwent standardized post-mortem assessments of AD and non-AD neuropathologic changes at autopsy. In a subset of 26 participants, we also analysed ante-mortem levels of plasma p-tau181 and neurofilament light (NfL). Reference biomarker values were obtained from 146 amyloid-PET-negative healthy controls (HC).Results:All CSF biomarkers clearly distinguished pathology-confirmed AD dementia (N=27) from HC (AUCs=0.86-1.00). CSF total-tau (t-tau), p-tau181, and their ratios with Aβ1-42, also accurately distinguished pathology-confirmed AD from non-AD dementia (N=8; AUCs=0.94-0.97). In pathology-specific analyses, intermediate-to-high Thal amyloid phases were best detected by CSF Aβ1-42 (AUC[95% CI]=0.91[0.81-1]), while intermediate-to-high CERAD neuritic plaques and Braak tau stages were best detected by CSF p-tau181 (AUC=0.89[0.79-0.99] and 0.88[0.77-0.99], respectively). Optimal Elecsys biomarker cut-offs were derived at 1097/229/19 pg/ml for Aβ1-42, t-tau, and p-tau181. In the plasma subsample, both plasma p-tau181 (AUC=0.91[0.86-0.96]) and NfL (AUC=0.93[0.87-0.99]) accurately distinguished pathology-confirmed AD (N=14) from HC. However, only p-tau181 distinguished AD from non-AD dementia cases (N=4; AUC=0.96[0.88-1.00]), and showed a similar, though weaker, pathologic specificity for neuritic plaques (AUC=0.75[0.52-0.98]) and Braak stage (AUC=0.71[0.44-0.98]) as CSF p-tau181.Conclusions:Elecsys-derived CSF biomarkers detect AD neuropathologic changes with very high discriminative accuracy in-vivo. Preliminary findings support the use of plasma p-tau181 as an easily accessible and scalable biomarker of AD pathology.Classification of Evidence:This study provides Class II evidence that fully-automated CSF t-tau and p-tau181measurements discriminate between autopsy-confirmed Alzheimer's disease and other dementias.

scholarly journals Plasma tau and neurofilament light in frontotemporal lobar degeneration and Alzheimer's disease

Neurology ◽  
2020 ◽  
pp. 10.1212/WNL.0000000000011226
Author(s):  
Ignacio Illán-Gala ◽  
Alberto Lleo ◽  
Anna Karydas ◽  
Adam M. Staffaroni ◽  
Henrik Zetterberg ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Disease Severity ◽  
Cortical Thickness ◽  
Frontotemporal Lobar Degeneration ◽  
Amyloid Pet ◽  
Class Iii ◽  
Neurofilament Light Chain ◽  
Neurofilament Light ◽  
T Tau

ObjectiveTo test the hypothesis that plasma total tau (t-tau) and neurofilament light chain (NfL) concentrations may have a differential role in the study of frontotemporal lobar degeneration syndromes (FTLD-S) and clinically-diagnosed Alzheimer's disease (AD-S), we determined their diagnostic and prognostic value in FTLD-S and AD-S and their sensitivity to pathologic diagnoses.MethodsWe measured plasma t-tau and NfL with the Simoa platform in 265 participants: 167 FTLD-S, 43 AD-S, and 55 healthy controls (HC), including 82 pathology-proven cases (50 FTLD-Tau, 18 FTLD-TDP, 2 FTLD-FUS, and 12 AD) and 98 participants with amyloid PET. We compared cross-sectional and longitudinal biomarker concentrations between groups, their correlation with clinical measures of disease severity, progression and survival and cortical thickness.ResultsPlasma NfL, but not plasma t-tau discriminated FTLD-S from HC and AD-S from HC. Both plasma NfL and t-tau were poor discriminators between FLTD-S and AD-S. In pathology confirmed cases, plasma NfL was higher in FTLD than AD and in FTLD-TDP compared to FTLD-Tau, after accounting for age and disease severity. Plasma NfL, but not plasma t-tau, predicted clinical decline and survival and correlated with regional cortical thickness in both FTLD-S and AD-S. The combination of plasma NfL with plasma t-tau did not outperform plasma NfL alone.ConclusionsPlasma NfL is superior to plasma t-tau for the diagnosis and prediction of clinical progression of FTLD-S and AD-S.Classification of evidenceThis study provides Class III evidence that plasma NfL has superior diagnostic and prognostic performance than plasma t-tau in FTLD and AD.

scholarly journals The Who, When, Why, and How of PET Amyloid Imaging in Management of Alzheimer’s Disease—Review of Literature and Interesting Images

Diagnostics ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 65 ◽  
Author(s):  
Subapriya Suppiah ◽  
Mellanie-Anne Didier ◽  
Sobhan Vinjamuri
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Area Under The Curve ◽  
Standard Uptake Value ◽  
Amyloid Imaging ◽  
Carrier Status ◽  
Amyloid Pet ◽  
Positron Emission ◽  
Cutoff Points ◽  
Pet Amyloid

Amyloid imaging using positron emission tomography (PET) has an emerging role in the management of Alzheimer’s disease (AD). The basis of this imaging is grounded on the fact that the hallmark of AD is the histological detection of beta amyloid plaques (Aβ) at post mortem autopsy. Currently, there are three FDA approved amyloid radiotracers used in clinical practice. This review aims to take the readers through the array of various indications for performing amyloid PET imaging in the management of AD, particularly using 18F-labelled radiopharmaceuticals. We elaborate on PET amyloid scan interpretation techniques, their limitations and potential improved specificity provided by interpretation done in tandem with genetic data such as apolipiprotein E (APO) 4 carrier status in sporadic cases and molecular information (e.g., cerebral spinal fluid (CSF) amyloid levels). We also describe the quantification methods such as the standard uptake value ratio (SUVr) method that utilizes various cutoff points for improved accuracy of diagnosing AD, such as a threshold of 1.122 (area under the curve 0.894), which has a sensitivity of 92.3% and specificity of 90.5%, whereas the cutoff points may be higher in APOE ε4 carriers (1.489) compared to non-carriers (1.313). Additionally, recommendations for future developments in this field are also provided.

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