Alzheimer's Research & Therapy最新文献

Background: As longevity increases and the population over age 65 expands, advancing age remains the most reliable predictor of cognitive decline, highlighting the need to identify biological mechanisms that support exceptional cognitive aging. We tested whether lower inherited risk of Alzheimer's disease (AD) dementia predicts SuperAger status (adults ≥ 80 years with episodic memory at least as good as middle-age adults) using prospectively enrolled SuperAgers and Cognitively Average Controls (Controls) from the multisite SuperAging Research Initiative.

Methods: We studied 231 participants (SuperAgers n = 142; Controls n = 89). We confirmed that the genetic ancestry structure across groups was comparable. We evaluated whether APOE status (ε2, ε3, ε4) and three AD polygenic risk scores (PRS) derived from large contemporary Genome-Wide Association Studies (GWAS) (PRS_Lambert, PRS_Wightman, PRS_Bellenguez) predicted SuperAging status using logistic regression models adjusted for age, sex, and education, considering ancestry interactions.

Results: APOE allele and genotype distributions did not differ between groups, and neither APOE nor any of the three PRS predicted SuperAger status. Results were unchanged when accounting for global non-European or African ancestry or principal components. In this well-characterized cohort, neither APOE nor contemporary PRS explained SuperAger status.

Conclusions: These findings suggest that the exceptional late-life memory phenotype that is characteristic of SuperAging is not explained by common-variant AD genetic risk captured by APOE or contemporary AD PRS, motivating a deeper investigation of potential rare genetic variations and experiential factors contributing to exceptional cognitive aging.

Background: Patients with Alzheimer's disease (AD) exhibit early alterations in the Default Mode Network (DMN), a key brain network involved in episodic memory where the precuneus plays a central role. Precision-targeted, non-invasive brain stimulation represents a promising strategy to improve cognitive function in individuals with dementia. The DMN can be modulated through personalized non-invasive electromagnetic stimulation, a therapeutic approach that enhances neural plasticity and stabilizes network connectivity. This trial implements an innovative therapeutic protocol based on precision delivery of personalized electromagnetic stimulation targeting the precuneus, the main hub of the DMN.

Methods: This phase 2 multicenter, randomized, double-blind, sham-controlled, three-arm trial evaluates the safety and efficacy of combined repetitive transcranial magnetic stimulation (rTMS) and transcranial alternating current stimulation (tACS) targeting the precuneus in AD patients. rTMS will be applied using the intermittent theta burst stimulation (iTBS) protocol, while tACS will be delivered at gamma frequency (70 Hz). Personalization of iTBS-tACS treatment is established using neuronavigated TMS with electroencephalography (TMS-EEG). The 24-week intervention starts with a 2-week intensive course of daily combined treatment over the precuneus (5 sessions per week), followed by a 22-week maintenance phase with weekly stimulation. The primary outcome measure is the change in the integrated Alzheimer Disease Rating Scale (iADRS) between baseline and week 24. Secondary outcomes include score changes in the Alzheimer's Disease Cooperative Study - Activities of Daily Living (ADCS-ADL) scale, Clinical Dementia Rating Scale-Sum of Boxes (CDR-SoB), the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog₁₃), the Mini-Mental State Examination (MMSE), the Montreal Cognitive Assessment (MoCA), the Frontal Assessment Battery (FAB), the Face-Name Association Task (FNAT), the Neuropsychiatric Inventory (NPI), and the Apathy Motivation Index (AMI). Exploratory outcomes will include changes in cortical activity and connectivity (assessed through TMS-EEG, MRI), in blood based biomarkers of neurodegeneration, synaptic activity and neural inflammation, and sensorimotor functions in virtual environments. Evaluation at week 12 and a follow-up assessment at week 32 will be conducted to assess short-term and follow-up treatment effects, respectively.

Significance: This trial aims to provide evidence that personalized combined electrical and magnetic stimulation of the DMN may slow functional and cognitive decline in AD patients, contributing to the development of personalized interventions for AD treatment.

Trial registration: ClinicalTrials.gov, NCT07075770, registered 10 July 2025.

Background: Resting-state functional MRI studies of Alzheimer's disease (AD) show lower functional connectivity (FC) of AD-relevant regions and resting-state networks in patients and transgenic rodent models at symptomatic stages. However, at early stages of the disease, both hyper and hypo connectivity has been reported. Traditional FC overlooks temporal fluctuations in connectivity and network dynamics at a short timescale captured by transient brain states such as co-activation patterns (CAPs). CAPs have been shown to be more sensitive than FC to detect early alterations in neurodegenerative diseases and therefore can shed light on hyper versus hypo connectivity observed at early stages. Moreover, how brain functional signatures of Alzheimer's disease are related to its behavioral and pathological markers and whether they have prognostic relevance remain scarcely investigated.

Methods: We acquired high temporal resolution resting-state functional MRI data in the TgF344-AD model rats and age-matched wild-type animals at 4 and 10 months of age corresponding to the pre-plaque and plaque stages, respectively and delineated brain functional alterations using FC and CAPs in the model animals. We also assessed the levels of amyloid beta (Aβ) in blood and working and reference memory performance in the same animals at the plaque stage and investigated their statistical relationship with pre-plaque and plaque-stage changes in FC and CAPs.

Results: TgF344-AD rats had significantly elevated blood Aβ levels, committed more working and reference memory errors and showed reduced hippocampal FC with the lateral cortical and default-mode-like network compared to wild-type animals at the plaque stage. FC at the pre-plaque stage did not differ between TgF344-AD and wild-type rats. TgF344-AD rats showed hyper- and hypo-activation in the default-mode-like-network and hippocampal regions at pre-plaque and plaque stages, respectively, in multiple CAPs. Blood Aβ levels were statistically explained more accurately by plaque-stage, than pre-plaque stage, FC values and CAP activations. CAP activations, especially at the pre-plaque stage, outperformed FC in accurate statistical explanation of memory impairments.

Conclusion: Our findings demonstrate pre-plaque stage hyperconnectivity not in the traditional, static measure of functional connectivity but in transient, dynamic brain states and that these early brain functional signatures have prognostic relevance for memory deficits in a translational rat model of Alzheimer's disease.

Alzheimer's disease (AD) is characterised by the accumulation of β-amyloid (Aβ) and tau proteins, resulting in neurodegeneration and cognitive decline. Although Aβ and tau disrupt synaptic function, the association linking these molecular pathologies to network-level dysfunction and memory impairment remains poorly understood. Here, we investigated the effects of Aβ and tau pathology (CSF Aβ42/40 ratio and tau phosphorylated at position 181, p-tau-181, respectively) on effective connectivity related to memory encoding, which may provide a link between synaptic pathology and cognitive outcomes. Functional magnetic resonance imaging (fMRI) during visual memory encoding was acquired from 205 participants in the multicentric DZNE Longitudinal Cognitive Impairment and Dementia Study (DELCODE) across the AD spectrum. Effective connectivity was assessed using Dynamic Causal Modelling (DCM) of task-fMRI data, focusing on the parahippocampal place area (PPA), hippocampus (HC), and precuneus (PCU)-regions central to memory encoding. Disruptions in connectivity between temporal and parietal lobes were associated with both memory impairment and indices of AD pathology. Specifically, reduced positive effective connectivity from the PCU to the PPA and from the HC to the PCU were linked to higher p-tau-181 levels, with an amplification effect observed in the presence of amyloid accumulation for the latter connectivity. The disruption from the PCU to the PPA was found to be associated with decreased memory performance. Together, these findings indicate that temporo-parietal connectivity is associated with both AD molecular pathology and, for a subset of connections, with memory performance.

Background: Alzheimer's disease (AD) disproportionately affects women, yet existing studies have been limited to single biofluids, individual hormones, or single dementia subtypes, leaving sex-stratified profiles across the cognitive impairment spectrum poorly defined. Here we address this gap by simultaneously quantifying nine steroid hormones spanning glucocorticoid (cortisol, 11-deoxycortisol), mineralocorticoid (aldosterone), progestogen (progesterone, 17-hydroxyprogesterone), androgen (testosterone, dihydrotestosterone), and estrogen (estradiol, estrone) pathways in paired CSF and plasma across five cognitive categories: no cognitive impairment, mild cognitive impairment (MCI) with AD pathology, MCI without AD pathology, AD dementia, and vascular dementia.

Methods: Steroid hormones were quantified by liquid chromatography-tandem mass spectrometry in paired cerebrospinal fluid (CSF) and plasma samples drawn from the same individuals from a cross-sectional study including 204 participants across five cognitive categories at the Danish Dementia Research Centre. Gender-stratified generalized linear models adjusted for age were applied. Cortisol findings were validated externally using the Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort (n = 426).

Results: Female participants with AD exhibited elevated CSF cortisol (fold change [FC] = 1.13; P = .04) and CSF 11-deoxycortisol (FC = 1.01; P = .03), alongside reduced plasma progesterone (FC = 0.90; P = .04). Male participants with AD showed elevated plasma aldosterone (FC = 1.19; P = 2.81e-03; q = 0.02). CSF cortisol correlated with amyloid-β42 and phosphorylated tau in female participants. ADNI validation confirmed elevated plasma cortisol in AD, with a larger effect in female participants.

Conclusions: Gender-dependent steroid hormone dysregulation in dementia highlights cortisol and aldosterone as potentially modifiable targets warranting further investigation.

Background: Alpha-band default mode network (DMN) connectivity declines with aging and Alzheimer's disease (AD), yet most electroencephalography (EEG) connectivity studies used pairwise (two-order) measures, such as mutual information rate (MIR). We leveraged O-information rate (OIR) to quantify three-order interactions and to separate redundant from synergistic information processing across frontal, temporal, and parietal DMN regions. We hypothesized that, extending established findings of reduced pairwise connectivity, (i) OIR (and its components) would be reduced in older versus younger adults and in AD versus healthy controls (HC); (ii) combining MIR with OIR would improve classification compared with MIR alone; and (iii) OIR measures would correlate positively with global cognition (as assessed by the Montreal Cognitive Assessment (MoCA)).

Methods: Resting-state EEG from two samples-healthy adult lifespan aging (95 younger; 93 older) and AD spectrum (44 HC; 84 amnestic mild cognitive impairment [aMCI]; 41 AD)-was source-localized using eLORETA to DMN regions. Alpha band (8-13 Hz) MIR and OIR were computed through multivariate spectral analysis. Group differences were tested using t-tests or analysis of covariance (ANCOVA) with multiple comparison correction. Classification (OIR, MIR, demographic, and combined feature sets) used cross-validated logistic-regression, linear-SVM, and random-forest models, with bootstrap 95% confidence intervals and DeLong tests for AUC comparisons.

Results: OIR and its redundancy component were significantly reduced in older versus younger adults and in AD versus HC/aMCI, with no HC-aMCI differences. The synergy component showed no group differences. MIR decreased broadly with aging and fronto-parietally in AD. Regarding classification (AD spectrum dataset, cross-validated AUC), OIR-based metrics outperformed MIR (AD vs. HC: 0.93 vs. 0.73; AD vs. aMCI: 0.93 vs. 0.71; aMCI vs. HC: 0.48 vs. 0.46). Combining demographics with all information-theoretic features improved AD vs. HC (0.98; DeLong p = 0.023) but not AD vs. aMCI (0.93), where OIR alone was already at ceiling; no feature set exceeded chance for aMCI vs. HC. After correction, OIR and its redundancy component correlated positively with MoCA scores; MIR and the synergy component did not.

Conclusions: Alpha-band three-order DMN interactions-particularly redundant information processing-decline with aging and AD and provide additional information beyond two-order connectivity for diagnostic classification. OIR offers complementary measures to traditional metrics, and future studies should examine its value when combined with more established AD biomarkers.

Background: Myelin dysfunction has emerged as a potentially pivotal factor in Alzheimer's disease (AD); however, its temporal dynamics and relationship with hallmark pathological processes remain incompletely understood. This study aimed to investigate dynamic demyelination and its association with the progression of Aβ and Tau pathology in AD.

Methods: A total of 1,237 participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI) with 18F-florbetapir (FBP) PET imaging were included. White matter SUVR (WM SUVR), defined as the adjusted FBP signal in white matter, was used as a proxy measure of myelin integrity. Cross-sectional and longitudinal analyses were conducted to examine associations between WM SUVR and AD progression, as well as AD-related biomarkers. Using cortical Aβ accumulation as a temporal reference, we further evaluated two-year changes in cortical Aβ and cumulative Tau PET signals in individuals with and without reduced myelin integrity (WM - vs. WM + uptake).

Results: WM SUVR demonstrated a gradual decline with advancing AD severity. Lower WM SUVR was associated with changes in Aβ_42/40 and pTau₁₈₁ levels in both cerebrospinal fluid (CSF) and plasma. In early-stage AD, the WM - group exhibited a higher two-year rate of cortical Aβ accumulation compared with the WM + uptake group. At comparable levels of cortical amyloid, the WM - group showed significantly higher Tau PET signals in temporal meta-regions of interest and more extensive cortical spread in later stages.

Conclusions: Progressive myelin dysfunction is observed across the course of AD as a notable perturbation within neurodegenerative processes. Early alterations in myelin integrity are associated with subsequent Aβ accumulation, whereas later changes coincide with increased Tau aggregation. These findings support a conceptual framework in which myelin degeneration shows temporally structured associations with AD pathology and may serve as a sensitive marker of vulnerability, particularly in early disease stages.

Background: Lecanemab, an amyloid-targeting monoclonal antibody, was recently approved for early symptomatic Alzheimer's disease in South Korea. Asians were underrepresented in prior trials, and real-world data from Korea remain scarce, particularly regarding treatment settings, adverse events, and barriers to scalability. We assessed the feasibility and safety of lecanemab among Korean patients in a real-world tertiary hospital.

Methods: A total of 112 patients initiated lecanemab treatment between December 2024 and October 2025 at Asan Medical Center. Prevalence of infusion-related reactions (IRRs), Amyloid-Related Imaging Abnormalities (ARIA), treatment discontinuation, and factors limiting implementation were evaluated.

Results: Among 112 patients (mean age 71 years; 59% female), IRRs occurred in 41 (37%) and were generally mild or moderate under active surveillance. Among 105 at-risk patients who received at least four infusions and had at least one monitoring MRI, ARIA developed in 20 (19%): ARIA-E/H in 6 (5.7%) and isolated ARIA-H in 14 (13.3%). Only 1 patient with isolated ARIA-H presented with transient confusion. Patients with ARIA-E/H were younger, whereas those with ARIA-H were older and more likely to have baseline microhemorrhages. Eleven out of 105 were APOE ε4/ε4 homozygotes, of whom 5 developed ARIA. The rapid increase in treatment demand exceeded outpatient infusion capacity, resulting in progressively longer waiting times-up to 20 weeks 9 months after program initiation.

Conclusion: This single-center experience from a tertiary referral hospital in Korea demonstrates that lecanemab treatment was feasible and generally well-tolerated, with manageable adverse events including ARIA and IRRs; however, limited infusion capacity, lack of reimbursement, and patient concentration in tertiary centers highlight the need for referral networks and system-level strategies to improve nationwide accessibility.

Background: We conceptualize the Real-World Reassessment Threshold (RWRT) as representing the smallest change that exceeds expected measurement variability while accounting for clinically expected cognitive decline over the assessment interval, whereas the minimum clinically important difference (MCID) indicates the smallest change likely to be clinically meaningful. To date, no study has empirically defined the RWRT or MCID for Mini-Mental State Examination (MMSE) scores in Lewy body dementia (LBD) or frontotemporal dementia (FTD), limiting the interpretation of longitudinal changes and clinical trial designs. We therefore aimed to estimate 12-month, diagnosis-specific MMSE thresholds for RWRT and MCID among individuals with LBD and FTD, and to evaluate the generalizability of these thresholds in an independent validation cohort.

Methods: This registry-based cohort study included individuals diagnosed with LBD or FTD from the Swedish Registry for Cognitive/Dementia Disorders (SveDem, 2007-2022) with a 91-400-day MMSE follow-up, and an independent validation cohort from the U.S. National Alzheimer's Coordinating Center (NACC). The RWRT was estimated using distribution-based methods based on intraclass correlation coefficients (ICCs). MCID was estimated using both anchor-based and distribution-based (0.5 standard deviation) approaches.

Results: We included 1,158 individuals from SveDem (873 LBD, 285 FTD) and 1,060 individuals from NACC (469 LBD, 591 FTD). Over the 91-400-day follow-up interval, MMSE scores demonstrated moderate to high reliability (ICC 0.70-0.90), corresponding to RWRT estimates ranged from 5 to 7 MMSE points. Anchor-based MCIDs differed by diagnosis, with a mean threshold of 0.7 points in LBD and 3.8 points in FTD in SveDem; similar diagnosis- and baseline severity-dependent patterns were observed in NACC. In contrast, distribution-based MCIDs were consistent across diagnoses, clustering around 2-3 MMSE points.

Conclusions: MMSE changes of less than five points over one year may reflect expected test variability combined with expected individual decline. However, average changes of 2-3 points may still be meaningful when combined with a clinical anchor of change, depending on diagnosis and disease stage. These results emphasize the importance of using both RWRT and MCID when evaluating MMSE change and selecting clinical trial endpoints.