Hemispheric asymmetry of tau pathology is related to asymmetric amyloid deposition in Alzheimer's Disease.

The distribution of tau pathology in Alzheimer's disease (AD) shows remarkable inter-individual heterogeneity, including hemispheric asymmetry. However, the factors driving this asymmetry remain poorly understood. Here we explore whether tau asymmetry is linked to i) reduced inter-hemispheric brain connectivity (potentially restricting tau spread), or ii) asymmetry in amyloid-beta (Aβ) distribution (indicating greater hemisphere-specific vulnerability to AD pathology).

Association of plasma Alzheimer's disease biomarkers with cognitive decline in cognitively unimpaired individuals.

Introduction: Plasma biomarkers' utility for predicting incident mild cognitive impairment (MCI) remains unclear. We evaluated associations of plasma Alzheimer's disease (AD) biomarkers and amyloid positron emission tomography (PET) with transitions from cognitively unimpaired (CU) to MCI in the Mayo Clinic Study of Aging (MCSA) and BioFINDER-2 studies.

Methods: Associations of continuous baseline plasma biomarker levels and amyloid PET Centiloid with progression to MCI, adjusting for age, sex, and education, were evaluated with Cox proportional hazards models.

Proteomic signatures of the and genetic variants and Alzheimer's disease.

The ε4 and ε2 alleles of the Apolipoprotein E ( ) gene confer opposite genetic risks for Alzheimer's disease (AD), but their underlying molecular mechanisms remain poorly characterized in humans. To resolve this, we systematically profiled -associated proteomic alterations across five cohorts-including the Global Neurodegeneration Proteomics Consortium (GNPC), BioFINDER-2, the Alzheimer's Disease Neuroimaging Initiative (ADNI), the Parkinson's Progression Markers Initiative (PPMI), and UK Biobank (UKB)-using SomaLogic and OLINK platforms in plasma and cerebrospinal fluid (CSF) from over 10,000 individuals. Using GNPC (plasma SomaLogic, N=4,045), we mapped a comprehensive -protein network and applied mediation modeling to classify genotype-related signals as upstream mediators, downstream consequences, or -specific changes.

The PREVENT-AD cohort: accelerating Alzheimer's disease research and treatment in Canada and beyond.

The PREVENT-AD is an investigator-driven study that was created in 2011 and enrolled cognitively normal older adults with a family history of sporadic AD. Participants are deeply phenotyped and have now been followed annually for more than 12 years [median follow-up 8.0 years,SD 3.

Tau, atrophy, and domain-specific cognitive impairment in typical Alzheimer's disease.

Introduction: A granular understanding of the mechanisms linking tau pathology to cognitive decline in Alzheimer's disease is crucial. We investigate mediating effects of medial temporal lobe (MTL) and neocortical neurodegeneration on tau-induced domain-specific cognitive impairment in amyloid-beta (Aβ) positive cognitively normal and impaired adults.

Methods: We assessed magnetic resonance imaging-derived MTL and neocortical volume/thickness and F-Flortaucipir positron emission tomography in 319 Aβ-positive individuals.

Personalised regional modelling predicts tau progression in the human brain.

Aggregation of the hyperphosphorylated tau protein is a central driver of Alzheimer's disease, and its accumulation exhibits a rich spatiotemporal pattern that unfolds during the course of the disease, sequentially progressing through the brain across axonal connections. It is unclear how this spatiotemporal process is orchestrated, namely, to what extent the spread of pathologic tau is governed by transport between brain regions, local production, or both. To address this, we develop a mechanistic model from tau PET data to describe tau dynamics along the Alzheimer's disease timeline.

Shared and disease-specific pathways in frontotemporal dementia and Alzheimer's and Parkinson's diseases.

Neurodegenerative diseases (NDs), such as Alzheimer's disease (AD), Parkinson's disease (PD) and frontotemporal dementia (FTD), exhibit distinct yet overlapping pathological mechanisms. Leveraging large-scale plasma proteomics data from the Global Neurodegeneration Proteomics Consortium, we analyzed 10,527 plasma samples (1,936 AD, 525 PD, 163 FTD, 1,638 dementia and 6,265 controls) to identify disease-specific and shared proteins across NDs. We identified 5,187 proteins significantly associated with AD, 3,748 with PD and 2,380 with FTD that revealed both common and divergent proteomic signatures, which were confirmed by multiple analytical approaches and orthogonal validation.

The Global Neurodegeneration Proteomics Consortium: biomarker and drug target discovery for common neurodegenerative diseases and aging.

More than 57 million people globally suffer from neurodegenerative diseases, a figure expected to double every 20 years. Despite this growing burden, there are currently no cures, and treatment options remain limited due to disease heterogeneity, prolonged preclinical and prodromal phases, poor understanding of disease mechanisms, and diagnostic challenges. Identifying novel biomarkers is crucial for improving early detection, prognosis, staging and subtyping of these conditions.

Benchmarking the AI-based diagnostic potential of plasma proteomics for neurodegenerative disease in 17,170 people.

Co-pathology is a common feature of neurodegenerative diseases that complicates diagnosis, treatment and clinical management. However, sensitive, specific and scalable biomarkers for in vivo pathological diagnosis are not available for most neurodegenerative neuropathologies. Here, we present ProtAIDe-Dx, a deep joint-learning model trained on 17,170 patients and controls that uses plasma proteomics to provide simultaneous probabilistic diagnosis across six conditions associated with dementia in aging.

Longitudinal tau aggregation, atrophy, and cognitive decline in Alzheimer's disease.

Introduction: The independent contributions of baseline and longitudinal tau positron emission tomography (PET) and magnetic resonance imaging (MRI) to cognitive decline remain unclear.

Methods: We included n = 761 amyloid-positive individuals from the Swedish BioFINDER-2 study with [F]RO948-tau-PET, 3-Tesla structural-MRI, and cognition (n = 322 with longitudinal imaging data). Linear-mixed-models with random-intercepts and -slopes or linear-regressions were adjusted for age, sex, education, diagnosis, and other-imaging-modality.

Characterizing spatiotemporal white matter hyperintensity pathophysiology in vivo to disentangle vascular and neurodegenerative contributions.

White matter hyperintensities (WMHs) are neuroimaging markers widely interpreted as caused by cerebral small vessel disease, yet emerging evidence suggests that a subset may have a neurodegenerative etiology. Current imaging methods have lacked the specificity to disentangle biological processes underlying WMHs . Here, we used voxel-level normative modeling and seven microstructural MRI markers with complementary biophysical sensitivities to generate single-subject high-resolution WMH pathophysiology maps in a large cohort (=32,526).

Evaluation of the Revised Criteria for Biological and Clinical Staging of Alzheimer Disease.

Importance: While clinical disease stages remained largely unchanged in the 2024 update of the Alzheimer disease (AD) criteria, tau-positron emission tomography (PET) was introduced as a core biomarker and its spatial extent was incorporated into the revised biological stages of the disease. It is important to consider both the clinical and the biological stages and understand their discrepancies.

Objective: To compare individuals who have discrepant biological and clinical stages with those who have congruent stages in terms of copathologies, comorbidities, and demographics.

Differential effects of aging, Alzheimer's pathology, and APOE4 on longitudinal functional connectivity and episodic memory in older adults.

Background: Both aging and Alzheimer's disease (AD) affect brain networks, with early disruptions occurring in regions involved in episodic memory. Few studies have, however, focused on distinguishing region-specific effects of AD-biomarker negative "normal" aging and early amyloid- and tau pathology on functional connectivity. Further, longitudinal studies combining imaging, biomarkers, and cognition are rare.

Plasma p-tau217 and tau-PET predict future cognitive decline among cognitively unimpaired individuals: implications for clinical trials.

Plasma p-tau217 and tau positron emission tomography (PET) are strong prognostic biomarkers in Alzheimer's disease (AD), but their relative performance in predicting future cognitive decline among cognitively unimpaired (CU) individuals is unclear. In a head-to-head comparison study including nine cohorts and 1,474 individuals, we show that plasma p-tau217 and medial temporal lobe tau-PET signal display similar associations with cognitive decline on a global cognitive composite test (R = 0.34 versus R = 0.

Sex Differences in Longitudinal Tau-PET in Preclinical Alzheimer Disease: A Meta-Analysis.

Importance: Alzheimer disease (AD) predominates in females at almost twice the rate relative to males. Mounting evidence in adults without AD indicates that females exhibit higher tau deposition than age-matched males, particularly in the setting of elevated β-amyloid (Aβ), but the evidence for sex differences in tau accumulation rates is inconclusive.

Objective: To examine whether female sex is associated with faster tau accumulation in the setting of high Aβ (as measured with positron emission tomography [PET]) and the moderating influence of sex on the association between APOEε4 carrier status and tau accumulation.

Machine learning prediction of tau-PET in Alzheimer's disease using plasma, MRI, and clinical data.

Introduction: Tau positron emission tomography (PET) is a reliable neuroimaging technique for assessing regional load of tau pathology in the brain, but its routine clinical use is limited by cost and accessibility barriers.

Methods: We thoroughly investigated the ability of various machine learning models to predict clinically useful tau-PET composites (load and laterality index) from low-cost and non-invasive features, for example, clinical variables, plasma biomarkers, and structural magnetic resonance imaging (MRI).

Results: Models including plasma biomarkers yielded the most accurate predictions of tau-PET burden (best model: R-squared = 0.

APOE4 impact on soluble and insoluble tau pathology is mostly influenced by amyloid-β.

The APOE4 allele is the strongest genetic risk factor for sporadic Alzheimer's disease (AD). Although APOE4 is strongly associated with amyloid-β (Aβ), its relationship with tau accumulation is less understood. Studies evaluating the role of APOE4 on tau accumulation showed conflicting results, particularly regarding the independence of these associations from Aβ load.

Precuneus Activity during Retrieval Is Positively Associated with Amyloid Burden in Cognitively Normal Older 4 Carriers.

The precuneus is a site of early amyloid-beta (Aβ) accumulation. Previous cross-sectional studies reported increased precuneus fMRI activity in older adults with mild cognitive deficits or elevated Aβ. However, longitudinal studies in early Alzheimer's disease (AD) are lacking and the relationship to the Apolipoprotein-E () genotype is unclear.

A comprehensive head-to-head comparison of key plasma phosphorylated tau 217 biomarker tests.

Plasma phosphorylated-tau 217 (p-tau217) is currently the most promising biomarker for reliable detection of Alzheimer's disease pathology. Various p-tau217 assays have been developed, but their relative performance is unclear. We compared key plasma p-tau217 tests using cross-sectional and longitudinal measures of amyloid-β (Aβ)-PET, tau-PET and cognition as outcomes and benchmarked them against CSF biomarker tests.

Synergistic association of Aβ and tau pathology with cortical neurophysiology and cognitive decline in asymptomatic older adults.

Animal and computational models of Alzheimer's disease (AD) indicate that early amyloid-β (Aβ) deposits drive neurons into a hyperactive regime, and that subsequent tau depositions manifest an opposite, suppressive effect as behavioral deficits emerge. Here we report analogous changes in macroscopic oscillatory neurophysiology in the human brain. We used positron emission tomography and task-free magnetoencephalography to test the effects of Aβ and tau deposition on cortical neurophysiology in 104 cognitively unimpaired older adults with a family history of sporadic AD.

Associations between misfolded alpha-synuclein aggregates and Alzheimer's disease pathology in vivo.

Introduction: We examined the relations of misfolded alpha synuclein (α-synuclein) with Alzheimer's disease (AD) biomarkers in two large independent cohorts.

Methods: We included Biomarkers for Identifying Neurodegenerative Disorders Early and Reliably Two (BioFINDER-2) and Alzheimer's Disease Neuroimaging Initiative (ADNI) participants (n = 2315, cognitively unimpaired, mild cognitive impairment, AD dementia) who had cross-sectional cerebrospinal fluid (CSF) α-synuclein measurement from seed-amplification assay as well as cross-sectional and longitudinal amyloid beta (Aβ) and tau levels (measured in CSF and/or by positron emission tomography). All analyses were adjusted for age, sex, and cognitive status.

Proteomic changes in Alzheimer's disease associated with progressive Aβ plaque and tau tangle pathologies.

Proteomics can shed light on the dynamic and multifaceted alterations in neurodegenerative disorders like Alzheimer's disease (AD). Combining radioligands measuring β-amyloid (Aβ) plaques and tau tangles with cerebrospinal fluid proteomics, we uncover molecular events mirroring different stages of AD pathology in living humans. We found 127 differentially abundant proteins (DAPs) across the AD spectrum.

A Comprehensive Head-to-Head Comparison of Key Plasma Phosphorylated Tau 217 Biomarker Tests.

Plasma phosphorylated-tau 217 (p-tau217) is currently the most promising biomarkers for reliable detection of Alzheimer's disease (AD) pathology. Various p-tau217 assays have been developed, but their relative performance is unclear. We compared key plasma p-tau217 tests using cross-sectional and longitudinal measures of amyloid-β (Aβ)-PET, tau-PET, and cognition as outcomes, and benchmarked them against cerebrospinal fluid (CSF) biomarker tests.