👤 Japanese Alzheimer’s Disease Neuroimaging Initiative

Apolipoprotein B (APOB), a structural component of low-density lipoproteins (LDL), has historically been associated with peripheral lipid transport and cardiovascular disease. Recent studies have revealed a link between APOB and Alzheimer's disease (AD), with increased cerebrospinal fluid (CSF) APOB levels correlating with tau pathology. Although APOB is known to be locally expressed in the brain, albeit at very low levels, its function in the central nervous system and contribution to neurodegenerative processes remains poorly understood. To investigate the effects of chronic APOB overexpression on brain molecular homeostasis, we used a transgenic mouse model expressing human APOB-100 and integrated findings with human cohort data to assess its functional relevance to AD pathology. Human APOB transgenic (hAPOB) and wild-type mice were aged to 6 and 12 months. Frontal cortices were analyzed using RNA sequencing and mass spectrometry-based proteomics. Differentially expressed genes and proteins were analyzed via pathway enrichment and cell type deconvolution. Findings were contrasted to post-mortem proteomic alterations observed in brain tissue (ROSMAP) and in the CSF (ADNI). hAPOB overexpression in mice induced a robust and persistent upregulation of innate immune genes, particularly those associated with type I interferon responses (Irf7, Ifit1, Oas2), in both young and old transgenic mice. Reduced microglial and endothelial cell signatures were observed through cell type deconvolution, which suggests immune activation without proliferation and possible blood-brain barrier damage. Proteomic analyses showed differentially expressed proteins associated with oxidative stress and dendritic remodeling. Proteins dysregulated in mice-such as CTSD, CRK, and SULT4A1-also showed altered expression in AD human brain and CSF. Remarkably, these proteins are dysregulated in the opposite direction in humans than in mice, unveiling a complex downstream regulation of APOB overexpression. Chronic hAPOB overexpression drives sustained neuroinflammatory and oxidative responses, potentially mimicking viral-like immune activation in the brain. The proteins dysregulated in hAPOB transgenic mice brains were also dysregulated in humans on opposite side of the APOB level spectrum. Nevertheless, this result shows a consistency across species on hAPOB-driven downstream effects. Some of these proteins were also shown to associate with key features of AD pathology, namely Aβ, Tau and pTau. Our findings support a novel role for APOB in modulating brain immune homeostasis and neurodegenerative processes, offering a mechanistic link between vascular risk and Alzheimer's disease. Show less

Clusterin, a multifunctional glycoprotein involved in proteostasis, amyloid-β clearance, and neuroinflammation, has been proposed as a biomarker in Alzheimer's disease (AD), but its stage-specific links to brain structure, tau pathology, and cognition remain unclear. This study evaluated plasma clusterin across the AD spectrum, its associations with brain volumes and CSF tau/p-tau, and whether structural brain measures mediate its cognitive effects. Data from 333 participants (CN = 38, MCI = 207, AD = 88) were analyzed using FDR-corrected regression, Pearson correlations, and mediation analyses, adjusting for demographic factors and APOE ɛ4 status. Results showed that plasma clusterin was highest in mild cognitive impairment (MCI) compared to cognitively normal (CN) and AD, suggesting a peak during early neurodegeneration. In CN participants, higher clusterin was associated with lower whole-brain volume, but it was not significantly related to hippocampal volumes or tau/p-tau. In MCI, clusterin was modestly associated with reduced whole-brain volume and elevated CSF tau, while associations with hippocampal volumes and p-tau were nonsignificant. In AD, higher clusterin was significantly associated with smaller left and right hippocampal volumes, with a trend toward lower whole-brain volume; no significant associations with tau or p-tau were observed. Based on the mediation analysis, in CN participants, no significant mediation effects of brain volumes were observed between plasma clusterin and cognitive function. In the MCI group, higher plasma clusterin was associated with lower whole-brain volume, and this volumetric measure showed significant indirect effects linking plasma clusterin to cognitive performance, consistent with indirect-only (full mediation) patterns. This suggests an indirect association whereby higher clusterin may be linked to poorer cognitive function through its association with reduced global brain volume. Likewise, in the AD group, higher clusterin levels were associated with lower whole-brain and right hippocampal volumes. Both measures significantly mediated the relationship between clusterin and cognitive performance, indicating that higher clusterin may be linked to poorer cognitive function through its association with reductions in global and region-specific brain volumes. Future studies should clarify the temporal and mechanistic pathways linking clusterin to neurodegeneration to determine its value as a biomarker and therapeutic target. Show less

The Apolipoprotein E ε4 (APOE ε4) allele and white matter hyperintensities (WMH) have been implicated in the pathogenesis of Alzheimer's disease (AD). To investigate the dual roles of WMH in statistically moderating and mediating the relationship of APOE ε4 with AD and related phenotypes, as well as the potential biological correlates. Data were derived from 34,783 non-demented participants in the UK Biobank (UKB; mean age = 55 years; follow-up = 4.3 years) and 863 in the Alzheimer's disease Neuroimaging Initiative (ADNI; mean age = 71.9 years; follow-up = 3.8 years). Multivariable models evaluated associations of APOE ε4 status, WMH, and their interaction with cognition, neurodegeneration, core pathologies, and AD risk. Mediation analyses were performed to quantify the extent to which WMH statistically explained ε4-outcome associations. Cerebrospinal fluid proteomic and bioinformatic analyses were used to explore biological clues in a subsample of ADNI (n = 708). APOE ε4 carriers exhibited larger WMH volumes (p < 0.001, UKB) and faster WMH change rates (p = 0.019, ADNI). In UKB, WMH statistically mediated a small proportion of associations between APOE ε4 and poorer numeric memory performance, smaller hippocampal volume, increased incident AD and all-cause dementia (ACD). In ADNI, WMH showed statistical mediation signals in the associations of APOE ε4 with faster rates of cognitive decline, amyloid-β (Aβ) deposition, and neurodegeneration. Notably, WMH interacted with APOE ε4 to exacerbate cognitive decline, hippocampal atrophy, and Aβ deposition. Proteomic analyses suggested that neuroinflammatory and axonal injury pathways may be associated with the observed mediating and moderating patterns. WMH mediated and enhanced the associations of APOE ε4 with AD-related phenotypes. These findings warrant further studies to clarify the underlying mechanisms and clinical implications. Show less

White matter (WM) is a key substrate for interregional neural communication and cognitive function but the role of WM glucose metabolism in cognitive aging has been understudied. Using multimodal neuroimaging (MRI, FDG-PET, amyloid-PET) from 3142 participants (15,287 visits) across two studies, we examined the contribution of WM to cognition and identified divergent WM signatures. Higher glucose metabolism in expected WM (EWM; corpus callosum and cingulum) was associated with better cognition, whereas increased metabolism in atypical WM (AWM; corona radiata) was linked to worse cognition, indicating a compensatory mechanism. EWM metabolism declined with aging, Alzheimer's disease (AD) progression (amyloid-β and APOE-ε4 carrier), and white matter hyperintensities, while AWM metabolism increased with aging and vascular risk but was partially weakened by AD neuropathology. Longitudinally, higher EWM and lower AWM metabolism predicted slower cognitive decline. Divergent WM metabolic patterns shed light on the dynamic role of WM in maintaining cognitive function. This study emphasizes the complementary information provided by WM metabolism for predicting future cognitive decline and identifying cognitive resilience. Show less

This study aimed to compare positron emission tomography (PET) and plasma-based temporal modeling of amyloid and tau biomarkers in Alzheimer's disease. Longitudinal amyloid PET (n = 1,097, mean age ± SD = 72.5 ± 7.38 year, 51.4% male), Plasma and PET models generated similar results for estimated amyloid and tau onset, with stronger model agreement for tau (r = 0.88[0.86, 0.89], t = 57.4, p < 0.001) than amyloid (r = 0.75[0.72, 0.77], t = 37.4, p < 0.001) onset. Accuracy of estimated onset compared to actual onset was high within modality (mean absolute error [MAE] ≤ 2.03) with slightly greater error (MAE 3.09-3.42) when comparing across modalities (ie, plasma to PET). For both plasma and PET, earlier tau onset was associated with younger amyloid onset, female sex, and ≥1 apolipoprotein (ApoE) ε4 allele. Earlier dementia onset after tau was associated with later tau onset for both plasma and PET, while male sex was associated with shorter tau to dementia gap in plasma models. Temporal modeling of plasma biomarkers provides comparable information to PET-based models, particularly for tau onset age, and can serve as a widely accessible tool for clinical assessment of biological disease severity. ANN NEUROL 2026. Show less

Lecanemab, an anti-amyloid beta (Aβ) protofibril antibody, was introduced in China in 2024, but its real-world performance remains unknown. In this prospective, multicenter study across 21 sites, 261 Alzheimer's disease patients (mild cognitive impairment to moderate dementia) received biweekly lecanemab (10 mg/kg). A matched Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort served as comparator. Cognitive tests, plasma biomarkers, and optional amyloid/tau positron emission tomography (PET) were assessed over 6 months. Lecanemab significantly attenuated cognitive decline versus ADNI. Plasma Aβ42, Aβ40, phosphorylated tau 217 (p‑tau217), glial fibrillary acidic protein (GFAP), and ratios showed robust changes; a p‑tau217 reduction correlated with amyloid PET clearance (mean -22.1 Centiloid; 29.2% turned amyloid-negative). Apolipoprotein E (APOE) ε4 non-carriers showed greater improvements. Infusion reactions occurred in 11.1% and amyloid-related imaging abnormalities in 9.2% (1.6% symptomatic), with no stage-related safety differences. Lecanemab was effective and well tolerated in real-world Chinese patients. Plasma p‑tau217 may serve as a sensitive, minimally invasive treatment-response biomarker. Show less

Olfactory dysfunction often emerges before cognitive symptoms and may signal early vulnerability to neurodegenerative processes. This study examined whether genetic risk, specifically the presence of the epsilon 4 allele in apolipoprotein E, is associated with altered functional connectivity between the hippocampus and olfactory regions. Resting-state functional imaging data from 126 participants (mean age = 71.8 years, SD = 6.9; 67 females) across a range of clinical stages were analyzed. Functional connectivity was computed between the hippocampus and four olfactory-related regions: anterior piriform cortex, posterior piriform cortex, olfactory bulb, and olfactory tract. Multiple regression models assessed whether genetic risk, age, sex, and clinical diagnosis predicted connectivity strength. Genetic risk was significantly associated with increased connectivity between the hippocampus and the olfactory tract (model R² = 0.12). A nominal APOE ε4 effect was also observed in the olfactory bulb, although the overall model did not reach significance, while no significant effects were observed in the piriform cortex regions. Clinical diagnosis was not a significant predictor of connectivity in any region. These results suggest that genetic risk is linked to early functional reorganization in specific olfactory-hippocampal pathways, particularly the olfactory tract, independent of clinical progression. The olfactory-hippocampal network may serve as a sensitive target for detecting early brain changes associated with neurodegenerative risk. Show less

Research suggests varying effects of fatty acids on cognitive function and brain structure in neurocognitive disorders, but inconsistent findings call for further investigation and advanced neuroimaging techniques. This study investigated the relationship between serum fatty acid levels (omega-3 PUFAs, omega-6 PUFAs, omega-6:omega-3 ratio, MUFAs, and SFAs) and temporal lobe volume in cognitively normal (CN) individuals, those with mild cognitive impairment (MCI), and those with Alzheimer's disease (AD). The results indicated that, as expected, there was a significant difference in temporal lobe volumes (p < 0.001), with the AD group showing more pronounced reductions in volume compared to both the CN and MCI groups. Unexpectedly, higher plasma omega-3 PUFA levels were associated with reduced temporal lobe volume (β = - 0.31, p = 0.021), and a lower omega-6:omega-3 ratio was also associated with diminished temporal lobe volume (β = 0.26, p = 0.039), both observed only in the AD group, after adjustment for age, gender, education, and APOE ε4 allele status as potential confounders. No significant associations were observed for any lipids with temporal lobe volumes in the CN or MCI groups. Interestingly, the only significant association observed between fatty acids and cognitive function was in the CN group, where higher MUFAs and SFAs were both associated with worse cognitive scores. In short, higher omega-3 PUFA levels and a lower omega-6:omega-3 ratio were associated with reduced temporal lobe volume in Alzheimer's patients not using fatty acid supplements. Notably, this observational cross-sectional study cannot establish causality and should be interpreted cautiously, as the findings may be influenced by residual confounding, non-fasting sampling, potential reverse causality, lack of detailed dietary and longitudinal data, and methodological constraints including limited lipid characterization and region-specific morphometric analysis. Further research is needed to confirm these findings and investigate potential mechanisms. Show less

This study investigated longitudinal plasma serotonin dynamics across the Alzheimer's disease (AD) continuum (cognitively normal [CN], mild cognitive impairment [MCI], and AD) to determine whether baseline serotonin and its 24-month change are associated with CSF amyloid-β (Aβ42), tau biomarkers, amyloid PET burden, structural brain integrity, and cognitive decline. Data from 959 ADNI participants (CN = 306, MCI = 421, AD = 232) with baseline and 24-month follow-up were analyzed. Measures included plasma serotonin, CSF biomarkers (Aβ42, total tau, p-tau181), florbetapir PET, MRI (hippocampal volume, cortical thickness), and cognitive tests (MMSE, ADAS-Cog 11, CDR-SB). Group differences were tested using ANOVA or Kruskal-Wallis, and associations were examined via partial correlations and mixed-effects models adjusted for age, sex, education, and APOE ε4, with FDR correction. The results revealed that baseline plasma serotonin levels showed a stepwise decline across the clinical continuum (CN > MCI > AD; p ≤ 0.05), consistent with progressive serotonergic dysregulation. In AD participants, higher baseline serotonin was significantly associated with less amyloid pathology and preserved brain structure, including higher CSF Aβ42 (β = 0.28, FDR p = 0.01), lower florbetapir PET SUVR (β = -0.31, FDR p = 0.02), and larger hippocampal volume (β = 0.33, FDR p = 0.02). Higher serotonin was also linked to better cognitive performance (MMSE: β = 0.22, FDR p = 0.02; ADAS-Cog 11: β = -0.24, FDR p = 0.02). Longitudinally, decreases in serotonin over 24 months in AD were associated with worsening amyloid burden (ΔPET SUVR: β = -0.29, FDR p = 0.02) and accelerated hippocampal atrophy (β = 0.32, FDR p = 0.01). Baseline serotonin predicted smaller 24-month declines in CSF Aβ42 (β = 0.28, FDR p = 0.01) and reduced hippocampal volume loss (β = 0.31, FDR p = 0.01). In CN and MCI groups, associations between serotonin and AD biomarkers or cognitive outcomes were not significant after FDR correction. On the whole, lower plasma serotonin levels are linked to amyloid pathology, hippocampal neurodegeneration, and cognitive decline in AD, supporting serotonin's potential as a stage-specific biomarker and mechanistic contributor to disease progression. Integrative longitudinal studies are needed to clarify causality and evaluate serotonergic pathways as therapeutic targets. Show less

Apolipoprotein E (APOE) and proprotein convertase subtilisin/kexin type 9 (PCSK9) are both lipid proteins and related to immunity/inflammation. We hypothesized that PCSK9 impacts on Alzheimer's disease (AD) risk in an We used the Framingham Heart Study (FHS) Offspring cohort (Gen 2), with data on plasma PCSK9 protein concentration, as the baseline exposure for 1,704 study subjects. Using Cox regression models, the outcomes were incidents of AD or all-cause dementia. Using another FHS dataset with 3,048 individuals with genetic data, we examined the association between PCSK9 genotypes and the incidence of AD/dementia, stratifying the analysis based on Higher plasma PCSK9 protein levels were associated with a lower risk of AD (HR [95%CI]: 0.74 [0.58, 0.94]; Our study suggests that high blood PCSK9 levels are protective against AD risk in Show less

Alzheimer's disease (AD) is characterized by amyloid-β (Aβ) accumulation and brain atrophy; however, the assocation between plasma Aβ biomarkers and regional neurodegeneration remains unclear. We investigated whether plasma Aβ42, Aβ40, and the Aβ42/40 ratio are associated with temporal lobe atrophy measured using tensor-based morphometry (TBM) in cognitively healthy controls (HC) and participants with mild cognitive impairment (MCI). We analyzed longitudinal MRI and plasma biomarkers data from 29 participants from ADNI (HC = 14, MCI = 15) with imaging and blood samples available at baseline, 24 months, and 48 months. TBM Jacobian maps were summarized within temporal lobe regions of interest (ROIs). Associations between plasma Aβ measures and TBM-derived atrophy were examined with linear mixed-effects models, adjusting for age, sex, and APOE ε4 status, with false-discovery-rate correction. Participants with MCI showed greater temporal lobe atrophy compared with HC people, with significantly lower TBM values at follow-up. Plasma Aβ42, Aβ40, and Aβ42/40 levels showed no consistent or robust differences between diagnostic groups. After covariate adjustment and FDR correction, no plasma Aβ-TBM associations were significant at baseline or 24 months. At 48 months, positive associations were identified between Aβ42 and temporal lobe atrophy (measure 2) in HC participants (β = 0.70, p = 0.046) and between Aβ40 and measure 2 in participants with MCI (β = 0.60, p = 0.036). In contrast, a negative association was observed between the Aβ42/40 and temporal lobe atrophy (measure 2) in MCI group (β = -0.53, p = 0.049). TBM captured greater temporal lobe atrophy in participants with MCI compared with HC. Plasma amyloids showed only limited and inconsistent associations with temporal lobe atrophy over time. These findings suggest that plasma Aβ measures alone may not reliably reflect longitudinal regional neurodegeneration in early AD. Show less

Alzheimer's disease (AD) disproportionately affects women and carriers of the apolipoprotein E ε4 allele (APOE4), yet little is known about how sex and APOE interact to influence white matter (WM) integrity during disease progression. We integrated diffusion MRI and matched blood transcriptomic data to investigate these interactions and their underlying biological mechanisms. WM microstructure was quantified using diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI), and regional vulnerability was assessed with a composite vulnerability score (CVS) derived from associations between diffusion features and AD severity across clinical traits in each of the four sex-APOE groups (female or male, with or without APOE4). Brain parcellation with the Eve atlas revealed regions consistently affected across sex-APOE groups (e.g., parahippocampal and superior temporal gyri) and regions specific to individual groups (e.g., the cingulum in females with APOE4 and the middle frontal gyrus in males without APOE4). Gene co-expression network analysis of the matched blood expression data identified gene subnetworks linked to group-specific regional vulnerability, including a muscle tissue morphogenesis module regulated by NEURL1B and HIST1H2BN associated with middle frontal gyrus vulnerability. These findings demonstrate that sex and APOE genotype jointly shape region-specific WM vulnerability and its molecular signatures in AD. Understanding these interactions provides novel mechanistic insights and may inform precision approaches to drug development, biomarker discovery, and clinical trial design for AD. Show less

Branched-chain amino acids (BCAAs) have been associated with cognitive function, with conflicting evidence suggesting both potential benefits and risks in neurodegenerative diseases such as Alzheimer’s disease (AD) and mild cognitive impairment (MCI), highlighting the need for further investigation. This study aimed to explore the relationship between total BCAAs, cognitive function, and brain structure, specifically examining hippocampal volumes and their potential mediating effects in individuals with AD, MCI, and cognitively normal (CN) individuals. Cognitive function was assessed using the CDR-SB scale, total BCAAs were measured in serum through NMR metabolomics, and hippocampal volumes were evaluated using voxel-based morphometry (VBM). This study found that elevated total BCAAs were initially associated with increased hippocampal volumes in MCI, though this relationship became non-significant after adjusting for confounding factors such as age, gender, education, and ApoE ɛ4 status. Increased hippocampal volumes, however, remained consistently linked to better cognitive function in both MCI and AD, regardless of adjustments. Importantly, mediation analysis revealed indirect effects of elevated total BCAAs on improved cognitive function via increased hippocampal volumes, with being significant only in MCI before controlling for confounders; however, this mediation relationship disappeared after adjusting for age, gender, education, and ApoE ɛ4 status. These findings suggested that BCAAs may be associated indirectly with improved cognitive function, with increased hippocampal volume acting as a key mediator, particularly in MCI. However, the effects of BCAAs were sensitive to confounding factors such as age, gender, education, and APOE-ɛ4 status, which we accounted for in our analyses; however, other unmeasured factors such as dietary intake may also affect the observed associations, underscoring the importance of considering these variables in future studies. Show less

Amyloid-β (Aβ) PET imaging is a core biomarker and is considered sufficient for the biological diagnosis of Alzheimer's disease (AD). However, it is typically reduced to a binary Aβ™/Aβ+ classification. In this study, we aimed to identify subgroups along the continuum of Aβ accumulation including subgroups within Aβ- and Aβ+. We used a total of 3,110 of Aβ PET scans from Alzheimer's Disease Neuroimaging Initiative (ADNI) and Anti-Amyloid Treatment in Asymptomatic Alzheimer's Disease (A4) datasets to develop Show less

We tested whether inflammation indexed by soluble tumor necrosis factor receptor-1 (sTNFR1) is related to cognitive decline. We examined serum sTNFR1 with cognition in the Health and Retirement Study (HRS) and cerebrospinal fluid (CSF) sTNFR1 with tau pathology and magnetic resonance imaging (MRI)-based atrophy in the Alzheimer's Disease Neuroimaging Initiative (ADNI). Finally, we used Mendelian randomization (MR) to assess associations between genetically proxied sTNFR1 and regional brain volumes. Data were from HRS (2016-2020; N = 6028) and ADNI (N = 287). In HRS, serum sTNFR1 was log-transformed (quartiles); in ADNI, CSF sTNFR1 was analyzed. Global cognition included word recall, serial 7 s, and counting backwards. In ADNI, cognition was measured by the Clinical Dementia Rating-Sum of Boxes (CDR-SB); CSF total tau/phosphorylated tau and longitudinal MRI regional volumes were analyzed. Associations were estimated with linear and linear mixed-effects models adjusted for demographic, clinical, and genetic covariates including apolipoprotein E ε4 (APOE ε4). Incident mild cognitive impairment (MCI)/dementia was modeled with cause-specific Cox and Fine-Gray models. Incremental prediction used optimism-corrected change in area under the curve (AUC; ΔAUC), net reclassification improvement (NRI)/integrated discrimination improvement (IDI), calibration, and decision curve analysis. MR used genome-wide association study (GWAS) statistics to test effects of genetically proxied sTNFR1 on MRI-derived regional volumes. In HRS (follow-up 4 years), higher serum sTNFR1 was associated with lower baseline cognition and faster decline in global cognition (β = - 0.16/year). Higher sTNFR1 predicted MCI/dementia (Cox HR ≈ 1.17; Fine-Gray sHR ≈ 1.14); among cognitively normal individuals, risk was elevated (OR = 1.30; 95% CI, 1.03-1.63). Adding sTNFR1 to 2- and 4-year prediction models conferred small discrimination gains after internal validation (ΔAUC ≤ 0.003) and minimal or inconsistent net clinical benefit. In ADNI, higher CSF sTNFR1 was associated with greater CSF total tau and phosphorylated tau, and predicted accelerated caudate atrophy. Exploratory MR suggested a nominal association with reduced right inferior temporal volume, limited by instruments. sTNFR1 is associated with cognitive decline and tau-related selective neurodegeneration, but provides limited incremental predictive value beyond established risk factors; external validation and replication are warranted. Show less

Plasma phosphorylated tau 217 (p-tau217) has shown strong potential as a blood-based biomarker for detecting amyloid pathology in Alzheimer's disease. This study evaluated the diagnostic and prognostic utility of plasma biomarkers, including p-tau217, in participants from the Japanese Alzheimer's Disease Neuroimaging Initiative (J-ADNI) cohort. We analyzed paired plasma and CSF samples from 172 J-ADNI participants. CSF and plasma biomarkers were quantified using the LUMIPULSE platform, and the same plasma samples were analyzed using the Simoa platform. The diagnostic accuracy for detecting amyloid pathology and the prognostic value of plasma p-tau217 biomarkers were assessed. Associations between plasma p-tau217 and polygenic risk scores (PRS), as well as potential confounding factors, were examined. Plasma p-tau217 levels measured using Lumipulse and Simoa assays were highly correlated (p < 0.001). All plasma p-tau217 assays showed high diagnostic accuracy for CSF Aβ42/Aβ40-defined amyloid pathology (AUC = 0.98). A single cutoff point based on the Youden index for p-tau217 and p-tau217/Aβ42 achieved >90% specificity and >90% sensitivity. The predefined FDA-approved two-cutoff model for p-tau217/Aβ42 was applicable to this cohort. PRS was significantly associated with plasma p-tau217 independently of APOE genotypes. Subjects with higher plasma p-tau217 levels showed a significantly increased risk of conversion to dementia and larger longitudinal cognitive declines. Plasma p-tau217 levels were significantly influenced by the body mass index, estimated glomerular filtration rate, and high-density lipoprotein cholesterol. Plasma p-tau217 and p-tau217/Aβ42 are robust biomarkers for AD diagnosis and prognosis in the Japanese population. Show less

Sporadic late-onset Alzheimer's disease (AD) is characterized by a long pre-clinical phase where amyloid-beta (Aβ) and tau begin to accumulate in the brain. The primary objective was to determine the age at which AD starts by finding the average population age when both positron emission tomography (PET) Aβ (Aβ-PET) and plasma Aβ42/40 become abnormal. Two high performance immunoprecipitation-mass spectrometry (IP-MS) assays (WashU/C2N and Shimadzu) were tested on samples from 1,450 participants who were diagnosed as cognitively unimpaired (CU), mild cognitive impairment (MCI), or AD-dementia across 4 international cohorts. Natural history modeling and trajectory analyses of the combined Aβ-PET and plasma Aβ42/40 data were analyzed. Data from both assays demonstrated Aβ42/40 undergoes a rapid change at approximately 15 Centiloid (CL), at an average population disease age at 66 years. On average, plasma Aβ42/40 becomes abnormal approximately 2 years before Aβ-PET, whereby it falls sharply to a stable level at the onset of preclinical AD. Average disease age where Aβ42/40 becomes abnormal, and the corresponding Centiloid level are lower for APOE allele carriers compared with non-carriers. Plasma Aβ42/40 ratio presents a step-like function of peripheral change shortly before the detection of plaques by Aβ-PET. Results are consistent with plasma Aβ42/40 falling to a steady-state level in participants with Aβ-PET levels greater than approximately 14CL for both assays. The age at which this occurs is dependent on APOE ε4 carriership, consistent with the approximate 7-year age difference in Centiloid abnormality between carriers and non-carriers. ANN NEUROL 2026;99:1327-1342. Show less

Hippocampal atrophy is a key marker of Alzheimer's disease (AD)-related neurodegeneration; however, hippocampal volume alone may not fully capture heterogeneity in cognitive decline. Hemispheric hippocampal asymmetry may provide complementary information, but its prognostic value for cognitive decline and clinical progression remains unclear. We studied 1,142 dementia-free participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI) with available baseline structural MRI, cerebrospinal fluid (CSF) amyloid-β (Aβ42) and phosphorylated tau (p-tau-181), and longitudinal cognitive follow-up. Total hippocampal volume (left + right) and hemispheric asymmetry (absolute left-right volumetric difference) were modeled simultaneously. Linear mixed-effects models examined associations with baseline performance and longitudinal change across memory, language, executive, and visuospatial domains. Cox proportional hazards models assessed risk of clinical progression to clinical dementia over up to 10 years of follow-up. All analyses adjusted for age, sex, education, APOE ε4 status, and CSF biomarkers, with stratification by amyloid status. The study cohort included 546 women (47.8%), with a mean age of 72.54 ± 6.98 years. Larger total hippocampal volume was consistently associated with better baseline performance and slower decline across all four cognitive domains, independent of amyloid and tau biomarkers. In contrast, greater hippocampal asymmetry was selectively associated with worse baseline memory performance and faster memory decline, independent of total hippocampal volume. In amyloid-stratified analyses, total hippocampal volume showed broad associations with cognition across all four domains among amyloid-positive participants and more limited, domain-specific associations among amyloid-negative participants, whereas hippocampal asymmetry was associated with memory only in amyloid-negative individuals. Regarding clinical progression to dementia, smaller total hippocampal volume was associated with higher risk of progression in the overall cohort and within both amyloid groups. In contrast, hippocampal asymmetry was associated with progression risk only among amyloid-negative individuals (hazard ratio per SD increase = 1.31, 95% CI: 1.03-1.65). Hippocampal total volume and asymmetry capture distinct aspects of neurodegeneration, with asymmetry providing additional prognostic information for memory decline and clinical progression in participants without detectable amyloid pathology. Show less

The genetic basis of sporadic early-onset Alzheimer's disease (EOAD) remains largely unknown, prompting evaluation of late-onset Alzheimer's disease (LOAD) polygenic risk in EOAD. A LOAD polygenic score (PGS) was calculated in the Longitudinal Early-onset Alzheimer's Disease Study (LEADS) and Alzheimer's Disease Neuroimaging Initiative (ADNI) study and tested for associations with AD risk, cognitive performance, and imaging and fluid biomarkers. Though PGS was elevated in LOAD and EOAD, it was not a significant predictor of EOAD adjusting for APOE ε4 carrier status and was not associated with age of EOAD onset (p = 0.106) or with cognitive performance (p = 0.417). In LEADS, greater LOAD PGS was associated with differences in neuroimaging and fluid biomarkers, including elevated synaptosomal-associated protein 25 (SNAP-25) (p = 2.3 × 10 While LOAD polygenic risk contributed minimally to EOAD onset and cognitive dysfunction, PGS association with fluid biomarkers in LEADS suggests a role for LOAD polygenic risk in EOAD pathophysiology. LOAD PGSs were elevated in both LOAD and EOAD compared to controls; however, LOAD PGS did not significantly predict EOAD risk, age at onset, or cognitive performance independent of APOE ε4 in the LEADS. Higher LOAD PGS was associated with lower amyloid PET Centiloids (less brain amyloid deposition) as well as lower CSF biomarker Aβ42 in LEADS (proxy marker suggesting higher brain amyloid deposition) in LEADS; these contradictory findings support the need for larger studies to further investigate whether LOAD PGS is associated with increased amyloid deposition in EOAD. Higher LOAD PGS was also associated with higher levels of CSF synaptosomal-associated protein 25 (SNAP-25), a key component of the SNARE complex, suggesting that LOAD genetic factors may contribute to dysregulation of synaptic transmission and/or pathological protein aggregation in EOAD. Show less

Mounting evidence implicates inflammation as a key factor in Alzheimer’s disease (AD) development. We previously identified pro-inflammatory soluble epoxide hydrolase (sEH) metabolites to be elevated in plasma and CSF of AD participants and to be associated with lower cognition in non-AD subjects. Soluble epoxide hydrolase is a key enzyme converting anti-inflammatory epoxy fatty acids to pro-inflammatory diols, reported to be elevated in multiple cardiometabolic disorders. Here we analyzed over 700 fasting plasma samples from the baseline of Alzheimer’s Disease Neuroimaging Initiative (ADNI) 2/GO study. We applied targeted mass spectrometry method to provide absolute quantifications of over 150 metabolites from oxylipin and endocannabinoids pathway, interrogating the role for inflammation/immune dysregulation and the key enzyme soluble epoxide hydrolase in AD. We provide further insights into the regulation of this pathway in different disease stages, APOE genotypes and between sexes. Additionally, we investigated in mild cognitive impaired (MCI) participants, metabolic signatures that inform about resilience to progression and conversion to AD. Key findings include I) confirmed disruption in this key central pathway of inflammation and pointed to dysregulation of sEH in AD with sex and disease stage differences; II) identified markers of disease progression and cognitive resilience using sex and ApoE genotype stratified analysis highlighting an important role for bile acids, lipid peroxidation and stress response hormone cortisol. In conclusion, we provide molecular insights into a central pathway of inflammation and links to cognitive dysfunction, suggesting novel therapeutic approaches that are based on targeting inflammation tailored for subgroups of individuals based on their sex, APOE genotype and their metabolic profile. The online version contains supplementary material available at 10.1186/s13195-025-01939-9. Show less

The spatial progression of longitudinal tau pathology has been inferred using cross-sectional data, but longitudinal voxel-wise analyses allow these patterns to be established without inference. We pooled 1426 flortaucipir (FTP) positron emission tomography (PET) scans from 583 participants across the aging and Alzheimer's disease (AD) spectrum from four studies. Using longitudinal tau-PET slope maps, we examined tau accumulation by clinical group and its associations with participant characteristics, baseline beta-amyloid (Aβ), and tau. Tau accumulation was limited to temporoparietal cortices in unimpaired participants but widespread in patients. Baseline Aβ, entorhinal, and inferior temporal tau predicted progressively more severe tau accumulation patterns. Age, sex, and apolipoprotein E (APOE) ε4 had modest moderating effects. Aβ and early tau interactions showed synergistic effects. Greater tau accumulation was linked to worse follow-up cognition than baseline. While Aβ influences early tau progression, baseline tau drives later progression. These results may guide future trials targeting tau accumulation at different disease stages. Faster tau spread from temporal to frontal lobes was linked to clinical impairment. Global beta-amyloid (Aβ), entorhinal, and inferior temporal gyrus (ITG) tau predicted progressively worse tau accumulation. Age, sex, and apolipoprotein E (APOE) had minimal effects on tau accumulation. Aβ and early tau burden interact synergistically to drive tau accumulation. More severe tau accumulation was linked to worse cognition at follow-up than baseline. Show less

This study aimed to identify CSF and plasma proteins that mediate the association between age and mild cognitive impairment (MCI) and Alzheimer's disease using mediation analysis. By focusing on proteins significantly associated in both CSF and plasma, we sought to identify biomarkers accessible for clinical applications. Proteomic measurements were obtained from CSF and plasma from a cohort of cognitively normal and MCI patients at the Johns Hopkins Alzheimer's Disease Research Center using Olink Proximity Extension Assay technology. Mediation effects were estimated using single- and multiple-mediator models and validated in three independent datasets: Duke (CSF), ADNI (CSF), and UK Biobank (plasma). Over 3000 proteins in 86 patients were analyzed. Three candidates, leiomodin-1 (LMOD1), glial fibrillary acidic protein (GFAP), and elastin (ELN), met the criteria for mediation in both CSF and plasma. Multiple mediator models demonstrated a significant combined mediation effect on MCI in CSF (OR: 1.122, 95 % CI: 1.026-1.439) and plasma (OR: 1.142, 95 % CI: 1.058-1.410). Across validation cohorts, GFAP consistently showed significant mediation effects (Duke CSF: OR: 1.114, 95 % CI: 1.069-1.206; ADNI: OR: 1.004, 95 % CI: 1.000-1.009; UK Biobank: OR: 1.030, 95 % CI: 1.026-1.034). In contrast, ELN and LMOD1 demonstrated mediation effects in the discovery dataset but were not consistently reproduced in external cohorts. Our findings highlight GFAP as a robust mediator of age-related risk of cognitive impairment across CSF and plasma, supporting its utility as a practical biomarker. ELN and LMOD1 may represent exploratory candidates reflecting extracellular matrix and vascular processes requiring further validation. Show less

Cirrhosis and hepatocellular carcinoma (HCC) are long-term complications of chronic liver disease (CLD). In this large multi-ancestry genome-wide association study of all-cause cirrhosis (35,481 cases, 2.36M controls) and HCC (6,680 cases, 1.76M controls), we identified 27 loci associated with cirrhosis (10 novel) and 11 with HCC (three novel). Three novel cirrhosis loci were replicated in independent cohorts (e.g. Show less

People with mild cognitive impairment (MCI) are candidates for early intervention, but not all progress to Alzheimer's disease (AD) dementia. Identifying a subgroup at highest risk may improve treatment targeting. We analyzed data from participants with MCI enrolled in the Alzheimer's Disease Neuroimaging Initiative (ADNI). Cognitive domains included memory, executive functioning, language, and visuospatial abilities. We evaluated baseline performance and 6-month change scores, using proportional hazards models to estimate associations with time to conversion to AD dementia. The strength of association varied by domain, but in general both baseline performance and 6-month change were associated with conversion. The strongest effects observed for memory and language. Observed associations were largely independent of established risk biomarkers, including APOE genotype, structural MRI measures, and CSF biomarkers. 6-month change scores on cognitive tests may help identify a high-risk subgroup of persons with MCI likely to progress to AD dementia. Systematic review. The authors reviewed the literature using traditional (e.g. PubMed) sources. There is a modest literature on change scores in the context of the AD clinical spectrum, but few investigations have evaluated whether short-term changes may be able to identify a high-risk subgroup of people with MCI. The authors have published a systematic review of this literature (Jutten et al. 2020) and appropriately refer to relevant citations here.Interpretation: Our findings suggest that short-term changes in cognition may be useful as part of a strategy to identify subsets of people with MCI who are at highest risk of conversion. Findings were clearest for memory and language. Domain-specific changes appeared to be independent from other biomarkers used to identify people at highest risk. Domain-specific changes did not appear to be better than changes in global cognition as measured by the MMSE or the CDR-sum of boxes.Future directions: Short-term changes in cognition may be useful to help identify a subgroup of people with MCI at highest risk of conversion to AD dementia. Future work could consider time frames shorter than the 6-month data we had available, better characterizing changes with more than 2 time points, or developing strategies that combine changes in cognition with other biomarkers to identify a subgroup of people with MCI to target for treatment. Show less

Early diagnosis of Alzheimer's disease (AD), particularly during its preclinical and prodromal phases, remains a major challenge. Plasma biomarkers such as phosphorylated tau at threonine 217 (p-tau217), amyloid-β (Aβ) isoforms, neurofilament light chain (NfL), and glial fibrillary acidic protein (GFAP) show promise for early detection; however, their relationships with medial temporal lobe (MTL) subfield atrophy and potential inter-biomarker pathways remain unclear. This study aimed to address this gap by investigating the associations between plasma biomarkers and MTL subfield atrophy, and by assessing potential mediation pathways. We conducted a cross-sectional study using data from 330 participants in the Alzheimer's Disease Neuroimaging Initiative (ADNI), including cognitively normal (CN) and mild cognitive impairment (MCI) groups. High-resolution coronal T2-weighted MRI quantified MTL subfield volumes using the ASHS protocol. Plasma biomarkers were measured using ultrasensitive immunoassays. The cohort included 209 CN participants (mean age [SD] = 69.3 [6.9] years; 64.2% women; 24.4% APOE ε4 carriers) and 121 MCI participants (mean age [SD] = 71.3 [7.3] years; 48.8% women; 27.9% APOE ε4 carriers). MCI individuals showed significantly higher plasma concentrations of p-tau217, p-tau217/Aβ Show less

New methods estimate amyloid positivity onset age (EAOA) from amyloid positron emission tomography (PET). We explore the genetics of EAOA to identify molecular factors underlying the earliest Alzheimer's disease (AD) changes. Harmonized amyloid PET data from 4216 participants were used in genome-wide survival, tissue-specific gene expression, and genetic covariance analyses of EAOA. Variants in apolipoprotein E (APOE), ABCA7, and RASGEF1C associated with earlier EAOA. APOE ε4/ε4 and ε3/ε4 converted 6.3 and 5 years earlier than ε3/ε3, respectively. ε2 was protective against earlier EAOA. rs4147929, an expression quantitative trait locus for ABCA7, associated with a 4 year earlier EAOA. This variant was associated with lower brain expression of ABCA7, which was associated with increased amyloid pathology at autopsy. Multiple immune-related diseases shared genetic covariance with EAOA. APOE, ABCA7, and RASGEF1C associated with earlier EAOA, with supporting evidence from tissue-specific expression analyses, offering insights into intervenable targets at early stages of AD. Novel methods estimate how long ago a patient converted to amyloid positivity. Estimating this amyloid clock allows us to determine the onset of the earliest Alzheimer's disease changes. We evaluated what genes influence when someone converts to amyloid positivity. Apolipoprotein E (APOE), ABCA7, and RASGEF1C associated with earlier age of amyloid positivity. Genetic results were supported by tissue-specific expression analyses. Show less

Evaluating prognostic performance of Alzheimer's biomarkers, multi-modal physiological measures, and clinical history in asymptomatic individuals versus established risk factors in asymptomatic individuals is can inform efficient screening strategies. To determine and compare the prognostic performance of amyloid biomarkers, multi-modal physiological measures, and clinical/modifiable risk factors We used clinical trials (A4/LEARN), longitudinal cohorts (ADNI, AIBL, HABS, NACC, OASIS), and the UK Biobank spanning 2004-2025 (median follow-up time range: 1.8-13.72 years) in time-varying survival and binary classification analyses. Settings included a United States clinical trial, longitudinal cohort studies spread across medical centers in the United States and Australia, and the volunteer-based UK Biobank. Patients were cognitively asymptomatic and age 65+ at baseline, and potentially progressed to either clinical impairment, clinical AD diagnosis, or incurred AD ICD-codes. Patients were volunteer or convenience samples. PTau-217, amyloid-PET, CSF markers (AB1-42, pTau-181, total-Tau), plasma proteomics, multi-modal brain-imaging, and cognitive tests were evaluated as predictors, along with demographics (age, sex, education), APOE genotype, and modifiable risk factors in the 2024 Lancet report PTau-217 and amyloid-PET from A4/LEARN were used to predict clinical impairment (CDR score of 0.5+ on two consecutive visits). PTau-217, amyloid-PET imaging across five cohorts, and CSF markers were used to predict clinical AD diagnosis. Plasma proteomics, multimodal neuroimaging, and cognitive assessments from the UK Biobank were used to predict AD ICD-codes. Sample-sizes ranged from 356-28,533 (31-519 cases; female percentages: 48.45-67.39). Models of demographics, APOE genotype, and risk-factors as predictors did not show statistically significant differences in time-dependent area under the receiver operating characteristic curve (AUROC) compared to separate models using amyloid biomarkers. Predicting cognitive impairment in A4/LEARN, pTau-217 improved AUROC by 0.045-0.084 (best: 0.616 (CI: 0.51-0.723) vs. 0.7 (CI: 0.609-0.793)). Amyloid-PET improved AD prediction (maximum AUROC increase 0.074; 0.561 (CI: 0.468-0.653) vs. 0.635 (CI: 0.537-0.733)), and CSF biomarkers showed slightly larger gains (maximum AUROC increase 0.127; 0.627 (CI: 0.438-0.816) vs. 0.754 (CI: 0.577-0.931)). In UK Biobank analyses, mean AUROC improvements were minor across proteomics (0.044), neuroimaging (0.143, with 99.8%/0.2% class-balance), and cognitive tests (0.064). In cognitively asymptomatic populations, biomarkers offer limited advantage over demographics, APOE genotype, and modifiable risk factors, supporting their importance in early AD screening strategies. Show less

Recent trials in Alzheimer's disease (AD) demonstrate encouraging outcomes. These trials target risk mechanisms identified through genetic analysis whilst directly aiming to reduce progression rates. Evidence from other neurodegenerative diseases suggests the genetics of progression is distinct from risk of disease. To expand these initial successes and improve clinical outcomes further we need to understand genetics of progression of disease. These can be deduced through rigorous analysis of meticulously phenotyped longitudinal cohorts. In this study we first looked at known genetic drivers of risk, namely polygenic risk scores for AD and A total of 387 individuals with, genetic data, amyloid positivity and in active decline (ADNI (n=222) and AIBL(n=165)) were used to perform generalised mixed effects linear model genome wide association studies of longitudinal cognitive decline as measured by mini mental state examination. The resulting summary statistics were subjected z, and colocalization analyses. Established AD risk factors, including These findings enhance our understanding of the biological underpinnings of AD progression, opening new avenues for therapeutic intervention. Show less

Mild cognitive impairment (MCI) represents a heterogeneous state between normal aging and dementia, with varied transition pathways. While factors influencing MCI progression are known, their role in cognitive reversal is unclear. This study analyzed 756 Alzheimer's Disease Neuroimaging Initiative (ADNI) participants, classified as progressive MCI (pMCI, N = 272, mean age = 75.10 ± 7.34 years), reversible MCI (rMCI, N = 52, mean age = 69.94 ± 7.98 years) and stable MCI (sMCI, N = 432, mean age = 73.34 ± 7.44 years) based on 36-month follow-up. We compared demographic, lifestyle, clinical, cognitive, neuroimaging, and biomarker data across groups and developed a prediction model. Patients in the rMCI group were significantly younger and had a higher level of education compared with those in the pMCI group. Memory, general cognition, daily functional activities, and hippocampal volume effectively distinguished all three groups. In contrast, Aβ, tau, and other brain regions were able to distinguish only between progressive and non-progressive cases. Informant-reported Everyday Cognition (Ecog) scales outperformed self-reported Ecog scales in differentiating subtypes and predicting progression. Multinomial regression revealed that higher education, larger hippocampal volume, and lower daily functional impairment were associated with reversion, whereas Show less