Volume 98, Number 3, 2024

Pages 741-754

Zhiwei Shen*, Xinyi Yang*, Yulong Lan, Gao Chen *These authors contributed equally to this work.
The Neuro-Inflammatory Microenvironment: An Important Regulator of Stem Cell Survival in Alzheimer’s Disease
Abstract: Alzheimer’s disease (AD) is the most common neurodegenerative disease, characterized by progressive memory loss and cognitive impairment due to excessive accumulation of extracellular amyloid-β plaques and intracellular neurofibrillary tangles. Although decades of research efforts have been put into developing disease-modifying therapies for AD, no “curative” drug has been identified. As a central player in neuro-inflammation, microglia play a key role in brain homeostasis by phagocytosing debris and regulating the balance between neurotoxic and neuroprotective events. Typically, the neurotoxic phenotype of activated microglia is predominant in the impaired microenvironment of AD. Accordingly, transitioning the activity state of microglia from pro-inflammatory to anti-inflammatory can restore the disrupted homeostatic microenvironment. Recently, stem cell therapy holds great promise as a treatment for AD; however, the diminished survival of transplanted stem cells has resulted in a disappointing long-term outcome for this treatment. This article reviews the functional changes of microglia through the course of AD-associated homeostatic deterioration. We summarize the possible microglia-associated therapeutic targets including TREM2, IL-3Rɑ, CD22, C5aR1, CX3CR1, P2X7R, CD33, Nrf2, PPAR-γ, CSF1R, and NLRP3, each of which has been discussed in detail. The goal of this review is to put forth the notion that microglia could be targeted by either small molecules or biologics to make the brain microenvironment more amenable to stem cell implantation and propose a novel treatment strategy for future stem cell interventions in AD.

Pages 755-772

Ali Aljassabi, Tarek Zieneldien, Janice Kim, Deepika Regmi, Chuanhai Cao (Handling Associate Editor: Bruce Citron)
Alzheimer’s Disease Immunotherapy: Current Strategies and Future Prospects
Abstract: Alzheimer’s disease (AD) is an extremely complex and heterogeneous pathology influenced by many factors contributing to its onset and progression, including aging, amyloid-beta (Aβ) plaques, tau fibril accumulation, inflammation, etc. Despite promising advances in drug development, there is no cure for AD. Although there have been substantial advancements in understanding the pathogenesis of AD, there have been over 200 unsuccessful clinical trials in the past decade. In recent years, immunotherapies have been at the forefront of these efforts. Immunotherapy alludes to the immunological field that strives to identify disease treatments via the enhancement, suppression, or induction of immune responses. Interestingly, immunotherapy in AD is a relatively new approach for non-infectious disease. At present, antibody therapy (passive immunotherapy) that targets anti-Aβ aimed to prevent the fibrillization of Aβ peptides and disrupt pre-existing fibrils is a predominant AD immunotherapy due to the continuous failure of active immunotherapy for AD. The most rational and safe strategies will be those targeting the toxic molecule without triggering an abnormal immune response, offering therapeutic advantages, thus making clinical trial design more efficient. This review offers a concise overview of immunotherapeutic strategies, including active and passive immunotherapy for AD. Our review encompasses approved methods and those presently under investigation in clinical trials, while elucidating the recent challenges, complications, successes, and potential treatments. Thus, immunotherapies targeting Aβ throughout the disease progression using a mutant oligomer-Aβ stimulated dendritic cell vaccine may offer a promising therapy in AD.

Pages 773-792
Systematic Review

Rachel H. Carr, Gina D. Eom, Eric E. Brown
Attention-Deficit/Hyperactivity Disorder as a Potential Risk Factor for Dementia and Other Neurocognitive Disorders: A Systematic Review
Abstract: Background: Attention-deficit/hyperactivity disorder (ADHD), a common neurodevelopmental condition now recognized to persist into older adulthood, has been postulated to be a risk factor for neurocognitive disorders given the overlap in clinical features and neurobiology, as well as the complex interplay between ADHD and known risk factors for dementia. Studies have emerged assessing this relationship, but there has not yet been a comprehensive systematic review addressing this topic. Objective: To assess whether ADHD is a risk factor for neurocognitive disorders and to explore possible mechanisms for such an association. Methods: A systematic review of the literature was conducted using Medline, Embase, and PsycINFO from inception until June 4, 2023. Studies were included if they assessed whether or how ADHD may be a risk factor for neurocognitive disorders. Studies were excluded if they were not primary literature, not published in a peer-reviewed journal, not in English, and/or used non-human subjects. Study quality was assessed using the QualSyst tool. Results: Sixteen studies met inclusion criteria. Seven studies found a positive association between ADHD and neurocognitive disorders (all-cause dementia in four studies, Alzheimer’s disease in three studies, Lewy body dementia in two studies, and mild cognitive impairment in one study). Four studies did not find an association. Five studies pertained to possible mechanisms for an association, including genetics, with minimal significant findings. Conclusions: ADHD may be a risk factor for certain neurocognitive disorders, although the evidence base is limited, and the absolute risk is small. Possible explanations include genetic and lifestyle factors.

Pages 793-823
Systematic Review

Ylermi Cabrera-León, Patricio García Báez, Pablo Fernández-López, Carmen Paz Suárez-Araujo (Handling Associate Editor: Yasunori Yamada)
Neural Computation-Based Methods for the Early Diagnosis and Prognosis of Alzheimer’s Disease Not Using Neuroimaging Biomarkers: A Systematic Review
Abstract: Background: The growing number of older adults in recent decades has led to more prevalent geriatric diseases, such as strokes and dementia. Therefore, Alzheimer’s disease (AD), as the most common type of dementia, has become more frequent too. Objective: The goals of this work are to present state-of-the-art studies focused on the automatic diagnosis and prognosis of AD and its early stages, mainly mild cognitive impairment, and predicting how the research on this topic may change in the future. Methods: Articles found in the existing literature needed to fulfill several selection criteria. Among others, their classification methods were based on artificial neural networks (ANNs), including deep learning, and data not from brain signals or neuroimaging techniques were used. Considering our selection criteria, 42 articles published in the last decade were finally selected. Results: The most medically significant results are shown. Similar quantities of articles based on shallow and deep ANNs were found. Recurrent neural networks and transformers were common with speech or in longitudinal studies. Convolutional neural networks (CNNs) were popular with gait or combined with others in modular approaches. Above one third of the cross-sectional studies utilized multimodal data. Non-public datasets were frequently used in cross-sectional studies, whereas the opposite in longitudinal ones. The most popular databases were indicated, which will be helpful for future researchers in this field. Conclusions: The introduction of CNNs in the last decade and their superb results with neuroimaging data did not negatively affect the usage of other modalities. In fact, new ones emerged.

Pages 825-835
Systematic Review

Itsuki Terao, Wakako Kodama
Comparative Efficacy, Tolerability, and Acceptability of Donanemab, Lecanemab, Aducanumab, Melatonin, and Aerobic Exercise for a Short Time on Cognitive Function in Mild Cognitive Impairment and Mild Alzheimer’s Disease: A Systematic Review and Network Meta-Analysis
Abstract: Background: The Food and Drug Administration (FDA) has approved lecanemab and aducanumab and is reviewing donanemab, but they have questionable efficacy, serious side effects and are costly, whereas melatonin administration and aerobic exercise for a short time may overcome these problems. Objective: We aim to compare the efficacy on cognitive function, tolerability and acceptability of melatonin administration and aerobic exercise for a short time with donanemab, lecanemab, and aducanumab in people with mild AD and MCI. Methods: We systematically reviewed relevant randomized placebo-controlled trials (RCTs) in PubMed, the Cochrane Library, CINHAL, and ClinicalTrials.gov and performed network meta-analyses. Results: The analysis included 10 randomized placebo-controlled trials with 4,599 patients. Although melatonin and aerobic exercise for a short time were significantly more effective than donanemab, lecanemab, aducanumab and placebo in the primary analysis, there was significant heterogeneity. In the sensitivity analysis excluding exercise, melatonin was significantly more effective than donanemab, lecanemab, aducanumab and placebo, with no significant heterogeneity. Aerobic exercise for a short time was significantly less acceptable than donanemab, aducanumab and placebo. Donanemab, lecanemab, and aducanumab were significantly less tolerable than placebo and donanemab and lecanemab were significantly less acceptable than placebo. Conclusions: Melatonin may be a better potential disease-modifying treatment for cognitive decline in mild AD and MCI. Aerobic exercise for a short time might also be better than donanemab, lecanemab and aducanumab if continued, as it is well tolerated and more effective, although less valid due to heterogeneity. Another limitation is the small number of participants.

Pages 837-857

Wesley Harrell Brooks
Polyamine Dysregulation and Nucleolar Disruption in Alzheimer’s Disease
Abstract: A hypothesis of Alzheimer’s disease etiology is proposed describing how cellular stress induces excessive polyamine synthesis and recycling which can disrupt nucleoli. Polyamines are essential in nucleolar functions, such as RNA folding and ribonucleoprotein assembly. Changes in the nucleolar pool of anionic RNA and cationic polyamines acting as counterions can cause significant nucleolar dynamics. Polyamine synthesis reduces S-adenosylmethionine which, at low levels, triggers tau phosphorylation. Also, polyamine recycling reduces acetyl-CoA needed for acetylcholine, which is low in Alzheimer’s disease. Extraordinary nucleolar expansion and/or contraction can disrupt epigenetic control in peri-nucleolar chromatin, such as chromosome 14 with the presenilin-1 gene; chromosome 21 with the amyloid precursor protein gene; chromosome 17 with the tau gene; chromosome 19 with the APOE4 gene; and the inactive X chromosome (Xi; aka “nucleolar satellite”) with normally silent spermine synthase (polyamine synthesis) and spermidine/spermine-N1-acetyltransferase (polyamine recycling) alleles. Chromosomes 17, 19 and the Xi have high concentrations of Alu elements which can be transcribed by RNA polymerase III if positioned nucleosomes are displaced from the Alu elements. A sudden flood of Alu RNA transcripts can competitively bind nucleolin which is usually bound to Alu sequences in structural RNAs that stabilize the nucleolar heterochromatic shell. This Alu competition leads to loss of nucleolar integrity with leaking of nucleolar polyamines that cause aggregation of phosphorylated tau. The hypothesis was developed with key word searches (e.g., PubMed) using relevant terms (e.g., Alzheimer’s, lupus, nucleolin) based on a systems biology approach and exploring autoimmune disease tautology, gaining synergistic insights from other diseases.

Pages 859-861

Jeffrey Cummings
“Landscape of Phase 2 Trials in Alzheimer’s Disease”: Perspective on Adaptive Trials
Abstract: Better means of conducting more efficient clinical trials for the development of Alzheimer's disease (AD) therapeutics are required. Adaptive clinical trial designs have many advantages based on the ability to make prespecified changes in the trial conduct depending on the ongoing experience in the trial. In their report in the Journal of Alzheimer's Disease, Lee and colleagues show that in the past 25 years only 2.5% of AD clinical trials have used adaptive designs. The report calls attention to the opportunity to use adaptive designs more often in Phase 2 clinical trials to improve trial efficiency and accelerate treatment development.

Pages 863-884
Maurizio Bergamino, Elizabeth Keeling, Molly McElvogue, Sydney Y. Schaefer, Anna Burke, George Prigatano, Ashley M. Stokes (Handling Associate Editor: Marco Bozzali)
White Matter Microstructure Analysis in Subjective Memory Complaints and Cognitive Impairment: Insights from Diffusion Kurtosis Imaging and Free-Water DTI
Abstract: Background: Dementia is characterized by a cognitive decline in memory and other domains that lead to functional impairments. As people age, subjective memory complaints (SMC) become common, where individuals perceive cognitive decline without objective deficits on assessments. SMC can be an early sign and may precede amnestic mild cognitive impairment (MCI), which frequently advances to Alzheimer's disease (AD). Objective: This study aims to investigate white matter microstructure in individuals with SMC, in cognitively impaired (CI) cohorts, and in cognitively normal individuals using diffusion kurtosis imaging (DKI) and free water imaging (FWI). The study also explores voxel-based correlations between DKI/FWI metrics and cognitive scores to understand the relationship between brain microstructure and cognitive function. Methods: Twelve healthy controls (HCs), ten individuals with SMC, and eleven CI individuals (MCI or AD) were enrolled in this study. All participants underwent MRI 3T scan and the BNI Screen (BNIS) for Higher Cerebral Functions. Results: The mean kurtosis tensor and anisotropy of the kurtosis tensor showed significant differences across the three groups, indicating altered white matter microstructure in CI and SMC individuals. The free water volume fraction (f) also revealed group differences, suggesting changes in extracellular water content. Notably, these metrics effectively discriminated between the CI and HC/SMC groups. Additionally, correlations between imaging metrics and BNIS scores were found for CI and SMC groups. Conclusions: These imaging metrics hold promise in discriminating between individuals with CI and SMC. The observed differences indicate their potential as sensitive and specific biomarkers for early detection and differentiation of cognitive decline.

Pages 885-896
Modi Zhai*, Yu Zhang*, Dongxue Yan, Yuzhen Wang, Wenzhong Li, Jie Sun (Handling Associate Editor: Guiyou Liu) *These authors contributed equally to this work.
Genetic Insights into the Association and Causality Between Blood Metabolites and Alzheimer’s Disease
Abstract: Background: Alzheimer's disease (AD) is an increasing public health concern with the aging of the global population. Understanding the genetic correlation and potential causal relationships between blood metabolites and AD may provide important insights into the metabolic dysregulation underlying this neurodegenerative disorder. Objective: The aim of this study was to investigate the causal relationship between blood metabolites and AD using Mendelian randomization (MR) analysis. Methods: Association data were obtained from three large-scale genome-wide association studies of 486 blood metabolites (N=7,824), AD (71,880 cases and 383,378 controls), early-onset AD (N=303,760), and late-onset AD (N=307,112). Causal associations between blood metabolites and AD were assessed using inverse variance weighting (IVW), MR-Egger, and weighted median methods. Bidirectional two-sample MR analysis was used to identify causal blood metabolites. MR-PRESSO, MR-Egger, and Cochran-Q were used to quantify instrumental variable heterogeneity and horizontal pleiotropy. Results: Using MR and sensitivity analysis, we identified 40 blood metabolites with potential causal associations with AD. After applying false discovery rate (FDR) correction, two metabolites, gamma-glutamylphenylalanine (OR = 1.15, 95% CI: 1.06-1.24, p = 3.88 × 10-4, q = 0.09) and X-11317 (OR = 1.16, 95% CI: 1.08-1.26, p = 1.14 × 10-4, q = 0.05), retained significant associations with AD. Reverse MR analysis indicated no significant causal effect of AD on blood metabolites. No significant instrumental variable heterogeneity or horizontal pleiotropy was found. Conclusions: This two-sample MR study provides compelling evidence for a potential causal relationship between blood metabolic dysregulation and susceptibility to AD. Further investigation of the biological relevance of the identified metabolites to AD and additional supporting evidence is warranted.

Pages 897-906
Xiao Luo*, Hui Hong*, Kaicheng Li, Qingze Zeng, Xiaocao Liu, Luwei Hong, Jixuan Li, Xinyi Zhang, Siyan Zhong, Xiaopei Xu, Yanxing Chen, Minming Zhang, Peiyu Huang, for the Alzheimer's Disease Neuroimaging Initiative *These authors contributed equally to this work.
Association Between Small Vessel Disease and Financial Capacity: A Study Based on Cognitively Normal Older Adults
Abstract: Background: Financial capacity is vital for the elderly, who possess a substantial share of global wealth but are vulnerable to financial fraud. Objective: We explored the link between small vessel disease (SVD) and financial capacity in cognitively unimpaired (CU) older adults via both cross-sectional and longitudinal analyses. Methods: 414 CU participants underwent MRI and completed the Financial Capacity Instrument-Short Form (FCI-SF). Subsequent longitudinal FCI-SF data were obtained from 104, 240, and 141 participants at one, two, and four years, respectively. SVD imaging markers, encompassing white matter hyperintensities (WMH), cerebral microbleeds (CMB), and lacune were evaluated. We used linear regression analyses to cross-sectionally explore the association between FCI-SF and SVD severity, and linear mixed models to assess how baseline SVD severity impacted longitudinal FCI-SF change. The false discovery rate method was used to adjust multiple comparisons. Results: Cross-sectional analysis revealed a significant association between baseline WMH and Bank Statement (BANK, β=-0.194), as well as between lacune number and Financial Conceptual Knowledge (FC, β=-0.171). These associations were stronger in APOE ε4 carriers, with β=-0.282 for WMH and BANK, and β=-0.366 for lacune number and FC. Longitudinally, higher baseline SVD total score was associated with severe FCI-SF total score decrease (β=-0.335). Additionally, baseline WMH burden predicted future decreases in Single Checkbook/Register Task (SNG, β=-0.137) and FC (β=-0.052). Notably, the association between baseline WMH and SNG changes was amplified in APOE ε4 carriers (β=-0.187). Conclusions: Severe SVD was associated with worse FCI-SF and could predict the decline of financial capacity in CU older adults.

Pages 907-923
Jing Cao*, Yating Tang*, Shujian Chen, Siqi Yu, Ke Wan, Wenwen Yin, Wenhui Zhen, Wenming Zhao, Xia Zhou , Xiaoqun Zhu, Zhongwu Sun (Handling Associate Editor: Jin-Tai Yu) *These authors contributed equally to this work.
The Hippocampal Subfield Volume Reduction and Plasma Biomarker Changes in Mild Cognitive Impairment and Alzheimer’s Disease
Abstract: Background: The hippocampus consists of histologically and functionally distinct subfields, which shows differential vulnerabilities to Alzheimer’s disease (AD)-associated pathological changes. Objective: To investigate the atrophy patterns of the main hippocampal subfields in patients with mild cognitive impairment (MCI) and AD and the relationships among the hippocampal subfield volumes, plasma biomarkers and cognitive performance. Methods: This cross-sectional study included 119 patients stratified into three categories: normal cognition (CN; N=40), MCI (N=39), and AD (N=40). AD-related plasma biomarkers were measured, including amyloid-β (Aβ)42, Aβ40, Aβ42/Aβ40 ratio, p-tau181, and p-tau217, and the hippocampal subfield volumes were calculated using automated segmentation and volumetric procedures implemented in FreeSurfer. Results: The subiculum body, cornu ammonis (CA) 1-head, CA1-body, CA4-body, molecular_layer_HP-head, molecular_layer_HP-body, and GC-ML-DG-body volumes were smaller in the MCI group than in the CN group. The subiculum body and CA1-body volumes accurately distinguished MCI from CN (area under the curve [AUC]=0.647–0.657). The subiculum-body, GC-ML-DG-body, CA4-body, and molecular_layer_HP-body volumes accurately distinguished AD from MCI (AUC=0.822–0.833) and AD from CN (AUC=0.903–0.905). The p-tau 217 level served as the best plasma indicator of AD and correlated with broader hippocampal subfield volumes. Moreover, mediation analysis demonstrated that the subiculum-body volume mediated the associations between the p-tau217 and p-tau181 levels, and the Montreal Cognitive Assessment and Auditory Verbal Learning Test recognition scores. Conclusions: Hippocampal subfields with distinctive atrophy patterns may mediate the effects of tau pathology on cognitive function. The subiculum-body may be the most clinically meaningful hippocampal subfield, which could be an effective target region for assessing disease progression.

Pages 925-940
Valeria Cogut, Taylor L. McNeely, Tyler J. Bussian, Sara I. Graves, Darren J. Baker
Caloric Restriction Improves Spatial Learning Deficits in Tau Mice
Abstract: Background: Caloric restriction (CR) has been recognized for its benefits in delaying age-related diseases and extending lifespan. While its effects on amyloid pathology in Alzheimer's disease (AD) mouse models are well-documented, its effects on tauopathy, another hallmark of AD, are less explored. Objective: To assess the impact of a short-term 30% CR regimen on age-dependent spatial learning deficits and pathological features in a tauopathy mouse model. Methods: We subjected male PS19 tau P301S (hereafter PS19) and age-matched wildtype mice from two age cohorts (4.5 and 7.5 months old) to a 6-week 30% CR regimen. Spatial learning performance was assessed using the Barnes Maze test. Tau pathology, neuroinflammation, hippocampal cell proliferation, and neurogenesis were evaluated in the older cohort by immunohistochemical staining and RT-qPCR. Results: CR mitigated age-dependent spatial learning deficits in PS19 mice but exhibited limited effects on tau pathology and the associated neuroinflammation. Additionally, we found a decrease in hippocampal cell proliferation, predominantly of Iba1+ cells. Conclusions: Our findings reinforce the cognitive benefits conferred by CR despite its limited modulation of disease pathology. Given the pivotal role of microglia in tau-driven pathology, the observed reduction in Iba1+ cells under CR suggests potential therapeutic implications, particularly if CR would be introduced early in disease progression.

Pages 941-955
Xin-Yan Xie*, Lin-Ya Huang*, Gui-Rong Cheng*, Dan Liu, Fei-Fei Hu, Jing-Jing Zhang, Gang-Bin Han, Xiao-Chang Liu, Jun-Yi Wang, Juan Zhou, De-Yang Zeng, Jing Liu, Qian-Qian Nie, Dan Song, Ya-Fu Yu, Chen-Lu Hu, Yi-Di Fu, Shi-Yue Li, Cheng Cai, Yu-Yang Cui, Wan-Ying Cai, Yi-Qing Li, Ren-Jia Fan, Hong Wan, Lang Xu, Yang-Ming Ou, Xing-Xing Chen, Yan-Ling Zhou, Yu-Shan Chen, Jin-Quan Li, Zhen Wei, Qiong Wu, Yu-Fei Mei, Wei Tan, Shao-Jun Song, Yan Zeng *These authors contributed equally to this work.
Association Between Long-Term Exposure to Ambient Air Pollution and the Risk of Mild Cognitive Impairment in a Chinese Urban Area: A Case-Control Study
Abstract: Background: As a prodromal stage of dementia, significant emphasis has been placed on the identification of modifiable risks of mild cognitive impairment (MCI). Research has indicated a correlation between exposure to air pollution and cognitive function in older adults. However, few studies have examined such an association among the MCI population in China. Objective: We aimed to explore the association between air pollution exposure and MCI risk from the Hubei Memory and Aging Cohort Study. Methods: We measured four pollutants from 2015 to 2018, 3 years before the cognitive assessment of the participants. Logistic regression models were employed to calculate odds ratios (ORs) to assess the relationship between air pollutants and MCI risk. Results: Among 4,205 older participants, the adjusted ORs of MCI risk for the highest quartile of PM2.5, PM10, O3, and SO2 were 1.90 (1.39, 2.62), 1.77 (1.28, 2.47), 0.56 (0.42, 0.75), and 1.18 (0.87, 1.61) respectively, compared with the lowest quartile. Stratified analyses indicated that such associations were found in both males and females, but were more significant in older participants. Conclusions: Our findings are consistent with the growing evidence suggesting that air pollution increases the risk of mild cognitive decline, which has considerable guiding significance for early intervention of dementia in the older population. Further studies in other populations and broader geographical areas are warranted to validate these findings.

Pages 957-967
Antonio Sánchez-Soblechero, Sara López-García, Carmen Lage, Marta Fernández-Matarrubia, Juan Irure, Marcos López-Hoyos, Julio Jiménez-Bonilla, Remedios Quirce, María de Arcocha-Torres, Oriana Cuenca-Vera, Juan Martín-Arroyo, Francisco Martínez-Dubarbie, Ana Pozueta, María García-Martínez, Jon Infante, Pascual Sánchez-Juan, Eloy Rodríguez-Rodríguez (Handling Associate Editor: Mikio Shoji)
Where Should I Draw the Line: PET-Driven, Data-Driven, or Manufacturer Cut-Off?
Abstract: Background: The optimal cut-off for Alzheimer’s disease (AD) CSF biomarkers remains controversial. Objective: To analyze the performance of cut-off points standardized by three methods: one that optimized the agreement between 11C-Pittsburgh compound B PET (a-PET) and CSF biomarkers (Aβ1-42, pTau, tTau, and Aβ1-42/Aβ1-40 ratio) in our population, called PET-driven; an unbiased cut-off using data from a healthy research cohort, called data-driven, and that provided by the manufacturer. We also compare changes in ATN classification. Methods: CSF biomarkers measured by the LUMIPULSE G600II platform and qualitative visualization of amyloid positron emission tomography (a-PET) were performed in all the patients. We established a cut-off for each single biomarker and Aβ1-42/Aβ1-40 ratio that optimized their agreement with a-PET using ROC curves. Sensitivity, Specificity, and Overall Percent of Agreement are assessed using a-PET or clinical diagnosis as gold standard for every cut-off. Also, we established a data-driven cut-off from our cognitively unimpaired cohort. We then analyzed changes in ATN classification. Results: One hundred and ten patients were recruited. Sixty-six (60%) were a-PET positive. PET-driven cut-offs were: pTau > 57, tTau > 362.62, Aβ1-42/Aβ1-40 < 0.069. For a single biomarker, pTau showed the highest accuracy (AUC 0.926). New PET-driven cut-offs classified patients similarly to manufacturer cut-offs (only two patients changed). However, 20 patients (18%) changed when data-driven cut-offs were used. Conclusions: We established our sample’s best CSF biomarkers cut-offs using a-PET as the gold standard. These cut-offs categorize better symptomatic subjects than data-driven in ATN classification, but they are very similar to the manufacturer’s.

Pages 969-986
Lan Shui, Dean Shibata, Kwun Chuen Gary Chan, Wenbo Zhang, Junhyoun Sung, David R. Haynor, Alzheimer’s Disease Neuroimaging Initiative (Handling Associate Editor: Ramon Casanova)
Longitudinal Relationship Between Brain Atrophy Patterns, Cognitive Decline, and Cerebrospinal Fluid Biomarkers in Alzheimer’s Disease Explored by Orthonormal Projective Non-Negative Matrix Factorization
Abstract: Background: Longitudinal magnetic resonance imaging (MRI) has been proposed for tracking the progression of Alzheimer's disease (AD) through the assessment of brain atrophy. Objective: Detection of brain atrophy patterns in patients with AD as the longitudinal disease tracker. Methods: We used a refined version of orthonormal projective non-negative matrix factorization (OPNMF) to identify six distinct spatial components of voxel-wise volume loss in the brains of 83 subjects with AD from the ADNI3 cohort relative to healthy young controls from the ABIDE study. We extracted non-negative coefficients representing subject-specific quantitative measures of regional atrophy. Coefficients of brain atrophy were compared to subjects with mild cognitive impairment and controls, to investigate the cross-sectional and longitudinal associations between AD biomarkers and regional atrophy severity in different groups. We further validated our results in an independent dataset from ADNI2. Results: The six non-overlapping atrophy components represent symmetric gray matter volume loss primarily in frontal, temporal, parietal and cerebellar regions. Atrophy in these regions was highly correlated with cognition both cross-sectionally and longitudinally, with medial temporal atrophy showing the strongest correlations. Subjects with elevated CSF levels of TAU and PTAU and lower baseline CSF Aβ42 values, demonstrated a tendency toward a more rapid increase of atrophy. Conclusions: The present study has applied a transferable method to characterize the imaging changes associated with AD through six spatially distinct atrophy components and correlated these atrophy patterns with cognitive changes and CSF biomarkers cross-sectionally and longitudinally, which may help us better understand the underlying pathology of AD.

Pages 987-1000
Calvin Trieu, Argonde C. van Harten, Anna E. Leeuwis, Lieza G. Exalto, Astrid M. Hooghiemstra, Inge M.W. Verberk, Cor P. Allaart, Hans-Peter Brunner-La Rocca, L. Jaap Kappelle, Robert J. van Oostenbrugge, Geert-Jan Biessels, Charlotte E. Teunissen, Wiesje M. van der Flier, on behalf of Heart-Brain Connection Consortium
Alzheimer’s Disease and Cognitive Decline in Patients with Cardiovascular Diseases Along the Heart-Brain Axis
Abstract: Background: We hypothesize that Alzheimer’s disease (AD)-related pathology may accelerate cognitive decline in patients with cardiovascular diseases. Objective: To investigate the association between blood-based biomarkers of AD, astrocyte activation, and neurodegeneration and cognitive decline. Methods: From the multi-center Heart-Brain study, we included 412 patients with heart failure, carotid occlusive disease or vascular cognitive impairment (age:68.6±9.0) and 128 reference participants (65.7±7.5). Baseline amyloid-β42/40 (Aβ42/40), phosphorylated-tau181 (pTau181), glial fibrillary acidic protein (GFAP), and neurofilament light (NfL) were determined using SiMoA (Quanterix). Memory, attention, language, and executive functioning were evaluated (follow-up:2.1±0.3 years). We applied linear mixed models with terms for biomarker, time and biomarker*time interactions, adjusted for age, sex, education, and site, to assess associations between biomarkers and cognitive decline. Results: Among patients, Aβ42/40 was not associated with cognitive performance at baseline. However, lower Aβ42/40 was associated with steeper decline in global cognition (β±SE:0.04±0.02). Higher pTau181 was associated with worse baseline performance on global cognition (-0.14±0.04) and memory (-0.31±0.09) and with steeper decline in global cognition (-0.07±0.02), memory (-0.09±0.04), attention (-0.05±0.02), and language (-0.10±0.03). Higher GFAP was associated with worse baseline performance on global cognition (-0.22±0.05), memory (-0.43±0.10), attention (-0.14±0.06), language (-0.15±0.05), and executive functioning (-0.15±0.05) and steeper decline in global cognition (-0.05±0.01). Higher NfL was associated with worse baseline performance on global cognition (-0.16±0.04), memory (-0.28±0.09), attention (-0.20 ±0.06), and executive functioning (-0.10±0.04), but was not associated with performance over time. In reference participants, no associations were found. Conclusions: Our findings suggest that blood-based biomarkers of AD-related pathology predict cognitive decline in patients with cardiovascular diseases.

Pages 1001-1016
Kelly Ceyzériat, Emma Jaques, Yesica Gloria, Aurélien Badina, Philippe Millet, Nikolaos Koutsouvelis, Giovanna Dipasquale, Giovanni B. Frisoni, Thomas Zilli, Valentina Garibotto, Benjamin B. Tournier
Low-Dose Radiation Therapy Impacts Microglial Inflammatory Response without Modulating Amyloid Load in Female TgF344-AD Rats
Background: Low-dose radiation therapy (LD-RT) has demonstrated in preclinical and clinical studies interesting properties in the perspective of targeting Alzheimer’s disease (AD), including anti-amyloid and anti-inflammatory effects. Nevertheless, studies were highly heterogenous with respect to total doses, fractionation protocols, sex, age at the time of treatment and delay post treatment. Recently, we demonstrated that LD-RT reduced amyloid peptides and inflammatory markers in 9-month-old TgF344-AD (TgAD) males. Objective: As multiple studies demonstrated a sex effect in AD, we wanted to validate that LD-RT benefits are also observed in TgAD females analyzed at the same age. Methods: Females were bilaterally treated with 2 Gy x 5 daily fractions, 2 Gy x 5 weekly fractions, or 10 fractions of 1 Gy delivered twice a week. The effect of each treatment on amyloid load and inflammation was evaluated using immunohistology and biochemistry. Results: A daily treatment did not affect amyloid and reduced only microglial-mediated inflammation markers, the opposite of the results obtained in our previous male study. Moreover, altered fractionations (2 Gy x 5 weekly fractions or 10 fractions of 1 Gy delivered twice a week) did not influence the amyloid load or neuroinflammatory response in females. Conclusions: A daily treatment consequently appears to be the most efficient for AD. This study also shows that the anti-amyloid and anti-inflammatory response to LD-RT are, at least partly, two distinct mechanisms. It also emphasizes the necessity to assess the sex impact when evaluating responses in ongoing pilot clinical trials testing LD-RT against AD.

Pages 1017-1027
Deirdre M. O’Shea, Simone Camacho, Reem Ezzeddine, Lilah Besser, Magdalena I. Tolea, Lily Wang, Conor Galvin, Gregory Gibbs, James E. Galvin
The Mediating Role of Cortical Atrophy on the Relationship between the Resilience Index and Cognitive Function: Findings from the Healthy Brain Initiative
Abstract: Background: Lifestyle factors are linked to differences in brain aging and risk for Alzheimer’s disease, underscored by concepts like 'cognitive reserve' and 'brain maintenance'. The Resilience Index (RI), a composite of 6 factors (cognitive reserve, physical and cognitive activities, social engagement, diet, and mindfulness) provides such a holistic measure. Objective: This study aims to examine the association of RI scores with cognitive function and assess the mediating role of cortical atrophy. Methods: Baseline data from 113 participants (aged 45+, 68% female) from the Healthy Brain Initiative were included. Life course resilience was estimated with the RI, cognitive performance with Cognivue®, and brain health using a machine learning derived Cortical Atrophy Score (CAS). Mediation analysis probed the relationship between RI, cognitive outcomes, and cortical atrophy. Results: In age and sex adjusted models, the RI was significantly associated with CAS (β = -0.25, p = 0.006) and Cognivue® scores (β = 0.32, p <0.001). The RI-Cognivue® association was partially mediated by CAS (β = 0.07; 95% CI [0.02, 0.14]). Conclusions: Findings revealed that the collective effect of early and late-life lifestyle resilience factors on cognition are partially explained by their association with less brain atrophy. These findings underscore the value of comprehensive lifestyle assessments in understanding the risk and progression of cognitive decline and Alzheimer’s disease in an aging population.

Pages 1029-1042
Francisco Martínez-Dubarbie, Sara López-García, Carmen Lage, Guglielmo Di Molfetta, Marta Fernández-Matarrubia, Ana Pozueta-Cantudo, María García-Martínez, Andrea Corrales-Pardo, María Bravo, Julio Jiménez-Bonilla, Remedios Quirce, Enrique Marco de Lucas, Marta Drake-Pérez, Diana Tordesillas, Marcos López-Hoyos, Juan Irure-Ventura, Elizabeth Valeriano-Lorenzo, Kaj Blennow, Nicholas J. Ashton, Henrik Zetterberg, Eloy Rodríguez-Rodríguez, Pascual Sánchez-Juan
Plasma Phosphorylated Tau 231 Increases at One-Year Intervals in Cognitively Unimpaired Subjects
Abstract: Background: Plasma biomarkers of Alzheimer's disease (AD) constitute a non-invasive tool for diagnosing and classifying subjects. They change even in preclinical stages, but it is necessary to understand their properties so they can be helpful in a clinical context. Objective: With this work we want to study the evolution of p-tau231 plasma levels in the preclinical stages of AD and its relationship with both cognitive and imaging parameters. Methods: We evaluated plasma phosphorylated (p)-tau231 levels in 146 cognitively unimpaired subjects in sequential visits. We performed a Linear Mixed-effects Model to analyze their rate of change. We also correlated their baseline levels with cognitive tests and structural and functional image values. ATN status was defined based on cerebrospinal fluid biomarkers. Results: Plasma p-tau231 showed a significant rate of change over time. It correlated negatively with memory tests only in amyloid-positive subjects. No significant correlations were found with any imaging measures. Conclusions: Increases in plasma p-tau231 can be detected at one-year intervals in cognitively healthy subjects. It could constitute a sensitive marker for detecting early signs of neuronal network impairment by amyloid.

Pages 1043-1052
Bruno Mario Cesana, Sverre Bergh, Alfonso Ciccone, Emmanuel Cognat, Andrea Fabbo, Sara Fascendini, Giovanni B. Frisoni, Lutz Froelich, Ron Handels, Maria Cristina Jori, Patrizia Mecocci, Paola Merlo, Oliver Peters, Magda Tsolaki, Carlo Alberto Defanti
Predictors of Nursing Home Placement in a Cohort of European People with Alzheimer’s Disease and Other Dementia Cases Enrolled in SCU-B or Non SCU-B centers: The RECage Study
Abstract: Background: Nursing home placement (NHP) can be the final step of patients with Alzheimer’s disease. Objective: We aimed to identify NHP predictors among 508 people with dementia with a 3‐year follow‐up. Methods: We analyzed data from the international observational RECage study, involving 508 people with especially Alzheimer’s disease and comparing a cohort enrolled by five centers with a Special Care Unit for BPSD (behavioral and psychological symptoms of dementia) and another one enrolled by six centers lacking this facility. The tertiary objective of the study was to assess the possible role of the SCU-B in delaying NHP. We assessed the relationship of the baseline characteristics with NHP by means of univariate analysis followed by Cox’s multivariate model. Results: Patients’ mean age was 78.1 years, 54.9% were women. Diagnosis mean age was 75.4 (±8.32) years; the main diagnosis was Alzheimer’s disease (296; 58.4%). During follow‐up, 96 (18.9%) patients died and 153 (30.1%) were institutionalized without a statistically significant difference between the two cohorts (p=0.9626). The mean NHP time was 902 (95%CI: 870-934). The multivariable analysis without death as a competing risk retained four independent predictors of NHP: age increase (hazard ratio (HR)=1.023, 95%CI: 1.000-1.046), patient education level increase (HR=1.062, 95%CI: 1.024-1.101), Neuropsychiatric Inventory total increase (HR=1018; 95%CI: 1.011–1.026), and total Mini-Mental State Examination as a favorable factor (HR=0.948, 95%CI: 0.925-0.971). Gender (females versus males: HR=1.265, 95%CI: 0.899-1.781) was included in the final Cox’s model for adjusting the estimates for. Conclusions: Our data partially agree with the predictors of NHP in literature including the effect of high education level. No caregivers’ factors were statistically significant.

Pages 1053-1067
Xueyi Zhang, Lissette Gomez, Jennifer Below, Adam Naj, Eden Martin, Brian Kunkle*, William S. Bush* (Handling Associate Editor: Andrew Saykin) *These authors contributed equally to this work.
An X Chromosome Transcriptome Wide Association Study Implicates ARMCX6 in Alzheimer’s Disease
Abstract: Background: The X chromosome is often omitted in disease association studies despite containing thousands of genes that may provide insight into well-known sex differences in the risk of Alzheimer’s disease (AD). Objective: To model the expression of X chromosome genes and evaluate their impact on AD risk in a sex-stratified manner. Methods: Using elastic net, we evaluated multiple modeling strategies in a set of 175 whole blood samples and 126 brain cortex samples, with whole genome sequencing and RNA-seq data. SNPs (MAF>0.05) within the cis-regulatory window were used to train tissue-specific models of each gene. We apply the best models in both tissues to sex-stratified summary statistics from a meta-analysis of Alzheimer’s Disease Genetics Consortium (ADGC) studies to identify AD-related genes on the X chromosome. Results: Across different model parameters, sample sex, and tissue types, we modeled the expression of 217 genes (95 genes in blood and 135 genes in brain cortex). The average model R2 was 0.12 (range from 0.03 to 0.34). We also compared sex-stratified and sex-combined models on the X chromosome. We further investigated genes that escaped X chromosome inactivation (XCI) to determine if their genetic regulation patterns were distinct. We found ten genes associated with AD at p < 0.05, with only ARMCX6 in female brain cortex (p=0.008) nearing the significance threshold after adjusting for multiple testing (α=0.002). Conclusions: We optimized the expression prediction of X chromosome genes, applied these models to sex-stratified AD GWAS summary statistics, and identified one putative AD risk gene, ARMCX6.

Pages 1069-1078
Ferris A. Ramadan, Gayatri Arani, Ayan Jafri, Tingting Thompson, Victoria L. Bland, Benjamin Renquist, David A. Raichlen, Gene E. Alexander, Yann C. Klimentidis
Mendelian Randomization of Blood Metabolites Suggests Circulating Glutamine Protects Against Late-Onset Alzheimer’s Disease
Abstract: Background: Late-onset Alzheimer’s disease (LOAD) represents a growing health burden. Previous studies suggest that blood metabolite levels influence risk of LOAD. Objective: We used a genetics-based study design which may overcome limitations of other epidemiological studies to assess the influence of metabolite levels on LOAD risk. Methods: We applied Mendelian randomization (MR) to evaluate bidirectional causal effects using summary statistics from the largest genome-wide association studies (GWAS) of 249 blood metabolites (n=115,082) and GWAS of LOAD (ncase=21,982, ncontrol=41,944). Results: MR analysis of metabolites as exposures revealed a negative association of genetically-predicted glutamine levels with LOAD (Odds Ratio (OR)=0.83, 95%CI=0.73, 0.92) that was consistent in multiple sensitivity analyses. We also identified a positive association of genetically-predicted free cholesterol levels in small LDL (OR=1.79, 95%CI=1.36, 2.22) on LOAD. Using genetically-predicted LOAD as the exposure, we identified associations with phospholipids to total lipids ratio in large LDL (OR=0.96, 95%CI=0.94, 0.98), but not with glutamine, suggesting that the relationship between glutamine and LOAD is unidirectional. Conclusions: Our findings support previous evidence that higher circulating levels of glutamine may be a target for protection against LOAD.

Pages 1079-1094
Lauren Podger, Walter F. Stewart, Daniel Serrano, Richard B. Lipton, David Gomez-Ulloa, Nicolai D. Ayasse, Frederick B. Barnes, E. Anne Davis, M. Chris Runken
Application of a Novel Endpoint Staging Framework: Proof of Concept in the AMBAR Study
Abstract: Background: A theoretical endpoint staging framework was previously developed and published, aligning outcomes (i.e., memory) to the stage of Alzheimer’s disease (AD) in which a given outcome is most relevant (i.e., has the greatest risk of degradation). The framework guides the selection of endpoints measuring outcomes relevant within a target AD population. Here, a proof of concept is presented via post-hoc analyses of the Alzheimer Management by Albumin Replacement (AMBAR) Phase 2b clinical trial in patients with AD (NCT01561053, 2012). Objective: To evaluate whether aligning endpoints measuring cognition, function, and quality of life to hypothesized ‘target’ stages of AD yields magnitudes of treatment efficacy greater than those reported in the AMBAR full analysis set (FAS). Methods: Three endpoints were tested: ADAS-Cog 12, ADCS-ADL, and QoL-AD. The magnitude of treatment efficacy was hypothesized to be maximized in the target stages of mild, mild-to-moderate, and very mild AD, respectively, compared to the full analysis set (FAS) and non-target stages. Results: For ADAS-Cog 12, the magnitude of treatment efficacy was largest in the non-target stage (-4.0, p=0.0760) compared to target stage and FAS. For ADCS-ADL and QoL-AD, the magnitude of treatment efficacy was largest in the target stage (14.2, p=0.0003; 2.4, p<0.0001, respectively) compared to non-target stage and FAS. Conclusions: Findings indicated that evaluating endpoints in the most relevant AD stage can increase the magnitude of the observed treatment efficacy. Evidence provides preliminary proof of concept for the endpoint staging framework.

Pages 1095-1106
Wen-Yih Isaac Tseng*, Yung-Chin Hsu*, Li-Kai Huang*, Chien-Tai Hong, Yueh-Hsun Lu, Jia-Hung Chen, Chin-Kun Fu, Lung Chan *These authors contributed equally to this work.
Brain Age Is Associated with Cognitive Outcomes of Cholinesterase Inhibitor Treatment in Patients with Mild Cognitive Impairment
Abstract: Background: The effect of cholinesterase inhibitor (ChEI) on mild cognitive impairment (MCI) is controversial. Brain age has been shown to predict Alzheimer’s disease conversion from MCI. Objective: The study aimed to show that brain age is related to cognitive outcomes of ChEI treatment in MCI. Methods: Brain MRI, the Clinical Dementia Rating (CDR) and Mini-Mental State Exam (MMSE) scores were retrospectively retrieved from a ChEI treatment database. Patients who presented baseline CDR of 0.5 and received ChEI treatment for at least 2 years were selected. Patients with stationary or improved cognition as verified by the CDR and MMSE were categorized to the ChEI-responsive group, and those with worsened cognition were assigned to the ChEI-unresponsive group. A gray matter brain age model was built with a machine learning algorithm by training T1-weighted MRI data of 362 healthy participants. The model was applied to each patient to compute predicted age difference (PAD), i.e. the difference between brain age and chronological age. The PADs were compared between the two groups. Results: 58 patients were found to fit the ChEI-responsive criteria in the patient data, and 58 matched patients that fit the ChEI-unresponsive criteria were compared. ChEI-unresponsive patients showed significantly larger PAD than ChEI-responsive patients (8.44 ± 8.78 years versus 3.87 ± 9.02 years, p = 0.0067). Conclusions: Gray matter brain age is associated with cognitive outcomes after 2 years of ChEI treatment in patients with the CDR of 0.5. It might facilitate the clinical trials of novel therapeutics for MCI.

Pages 1107-1119
Henriette Seltmann, Birgit Teichmann
Dementia Knowledge, Attitude Toward Dementia and Confidence in Dementia Care: Impact of a Dementia Training on German Nursing Students
Abstract: Background: The number of people with dementia (PwD) in acute care hospitals is steadily increasing, posing a challenge for those who work closely with patients. To date, no German study has addressed the extent to which prospective nurses benefit from dementia training in terms of their knowledge, attitudes, and confidence in caring for PwD. Objective: The aim of this study is to investigate whether a validated dementia training for registered nurses can positively change nursing students’ knowledge about dementia, their attitude toward PwD, and their confidence in caring for them, as well as the stability over time. Methods: In the one-group pre-test, post-test design, a sample of 81 nursing students was recruited from two nursing schools in Germany between May and June 2023. They completed a questionnaire consisting of the Dementia Knowledge Assessment Scale, the Dementia Attitude Scale, and the Confidence in Dementia Scale, as well as sociodemographic questions and experiences with PwD at three measurement points. The data were analyzed using the Wilcoxon test and repeated measures ANOVA. Results: The training has a significant effect on knowledge in dementia (z = -5.07, p < 0.001), attitude toward PwD (z = -4.42, p < 0.001) and confidence in caring for them at the post-test (z = -3. 21, p < 0.001, r = 0.36). The repeated measures ANOVA shows stability over time only for dementia knowledge. Conclusions: The results indicate the need for further research in this field as well as the validation of the dementia training specifically addressing nursing students.

Pages 1121-1131
Ping Zhong, Qing Cao, Zhen Yan
Distinct and Convergent Alterations of Entorhinal Cortical Circuits in Two Mouse Models for Alzheimer’s Disease and Related Disorders
Abstract: Background: The impairment of neural circuits controlling cognitive processes has been implicated in the pathophysiology of Alzheimer’s disease and related disorders (ADRD). However, it is largely unclear what circuits are specifically changed in ADRD, particularly at the early stage. Objective: Our goal of this study is to reveal the functional changes in the circuit of entorhinal cortex (EC), an interface between neocortex and hippocampus, in AD. Methods: Electrophysiological, optogenetic and chemogenetic approaches were used to examine and manipulate entorhinal cortical circuits in amyloid-β familial AD model (5xFAD) and tauopathy model (P301S Tau). Results: We found that, compared to wild-type mice, electrical stimulation of EC induced markedly smaller responses in subiculum (hippocampal output) of 5xFAD mice (6-month-old), suggesting that synaptic communication in the EC to subiculum circuit is specifically blocked in this AD model. In addition, optogenetic stimulation of glutamatergic terminals from prefrontal cortex (PFC) induced smaller responses in EC of 5xFAD and P301S Tau mice (6-month-old), suggesting that synaptic communication in the PFC to EC pathway is compromised in both ADRD models. Chemogenetic activation of PFC to EC pathway did not affect the bursting activity of EC neurons in 5xFAD mice, but partially restored the diminished EC neuronal activity in P301S Tau mice. Conclusions: These data suggest that 5xFAD mice has a specific impairment of short-range hippocampal gateway (EC to subiculum), which may be caused by amyloid-β deposits; while two ADRD models have a common impairment of long-range cortical to hippocampal circuit (PFC to EC), which may be caused by microtubule/tau-based transport deficits. These circuit deficits provide a pathophysiological basis for unique and common impairments of various cognitive processes in ADRD conditions.

Pages 1133-1143
Shuang-Ling Han, Ya-Nan Ou, Bao-Lin Han, Hai-Hua Guo, Hao-Chen Chi, Yi-Ming Huang, Hui-Fu Wang, Lan Tan (Handling Associate Editor: Yong Liu)
Total Tau Protein Mediates the Association of Ischemic Cerebrovascular Disease with Cognitive Decline
Abstract: Background: Patients with transient ischemic attack (TIA) or ischemic stroke demonstrate an increased risk of cognitive dysfunction. Accumulating evidence indicates that ischemic cerebrovascular disease (ICVD) may interact with the amyloid/tau/neurodegeneration (AT[N]) biomarkers to promote dementia. However, the precise pathological mechanisms remain to be fully characterized. Objective: To elucidate the interrelationships among ICVD, ATN biomarkers in cerebrospinal fluid (CSF), and cognition. Methods: A total of 2524 participants were recruited from the CABLE study. ICVD referred to TIA/ischemic stroke. Cognitive performance was assessed by China Modified Mini-Mental State Examination (CM-MMSE) and Montreal Cognitive Assessment-b (MoCA-b). Multivariate linear regression analyses were performed to evaluate the associations of ICVD with CSF ATN biomarkers and cognition. Causal mediation analyses were used to identify whether the association was mediated by ATN biomarkers. Results: ICVD was associated with higher total-tau (t-tau) (p = 2.828×10-2) and poorer cognition (CM-MMSE: p = 1.539×10-5, MoCA-b: p = 4.552×10-6). Additionally, no discernible correlation surfaced between ICVD and amyloid-β (Aβ) 42 (p = 6.910×10-1) or phosphorylated tau (p-tau) (p = 4.324×10-1). The influence of ICVD on cognitive function was partially mediated by CSF t-tau (CM-MMSE: proportion: 2.74%, MoCA-b: proportion: 2.51%). Subgroup analyses revealed the influences of t-tau were especially evident in male (CM-MMSE: proportion: 5.45%, MoCA-b: proportion: 5.38%) and mid-life group (CM-MMSE: proportion: 9.83%, MoCA-b: proportion: 5.31%). Conclusions: These results delineated t-tau as a potential mediator for the influence of ICVD on cognition. Targeting brain ischemia and alleviating neuronal injury induced by ischemia may be a promising approach for preventing cognitive decline.

Pages 1145-1155
Amelia Papadimitriou, Aprill Z. Dawson, Abigail Thorgerson, Sanjay Bhandari, Martin Martinez, Leonard E. Egede
Understanding the Relationship Between Wealth and Cognitive Function by Race/Ethnicity Among Older United States Adults with Diabetes
Abstract: Background: The prevalence of type 2 diabetes is increasing with the burden disproportionately falling on older adults and racial/ethnic minorities. Older adults with diabetes show greater cognitive decline and there are disparities in cognitive function by race/ethnicity that can be explained by social determinants such as wealth. Objective: To understand whether there is a differential relationship between wealth and cognitive function by race/ethnicity among older U.S. adults with diabetes. Methods: Data on 9,006 adults aged 50+ with diabetes from the Health and Retirement Study (2006–2016) were analyzed. The primary outcome, cognitive function, was a score ranging from range 0-27 categorized as: normal [12-27], mild cognitive impairment (MCI) [7-11], and dementia including Alzheimer’s disease [0-6]. Three modeled outcomes were: 1) normal versus MCI, 2) normal versus dementia, 3) MCI versus dementia. Wealth was log transformed and used as continuous and binary (≥ median, < median). Logistic generalized estimating equation models were used to examine the relationship between wealth and cognitive function and models were stratified by race/ethnicity. Models were adjusted for demographics, lifestyle, functional limitations, and comorbidities. Results: In adjusted models, greater wealth was significantly associated with lower odds of MCI and dementia for all groups. Similarly, having wealth less than the sample median was associated with higher odds of MCI and dementia compared to wealth ≥ sample median. Conclusions: Increased wealth was significantly protective against MCI and dementia for all ethnic groups. Wealth less than the sample median was associated with greater odds of dementia for NHB and NHW.

Pages 1157-1167
Tânia Soares Martins, Maria Ferreira, Sandra Magalhães, Kevin Leandro, Luís P. de Almeida, Jonathan Vogelgsang, Benedict Breitling, Niels Hansen, Hermann Esselmann, Jens Wiltfang, Odete A.B. da Cruz e Silva, Alexandra Nunes, Ana Gabriela Henriques
FTIR Spectroscopy and Blood-Derived Extracellular Vesicles Duo in Alzheimer’s Disease
Abstract: Background: Alzheimer’s disease (AD) diagnosis is difficult, and new accurate tools based on peripheral biofluids are urgently needed. Extracellular vesicles (EVs) emerged as a valuable source of biomarker profiles for AD, since their cargo is disease-specific and these can be easily isolated from easily accessible biofluids, as blood. Fourier Transform Infrared (FTIR) spectroscopy can be employed to analyze EVs and obtain the spectroscopic profiles from different regions of the spectra, simultaneously characterizing carbohydrates, nucleic acids, proteins, and lipids. Objective: The aim of this study was to identify blood-derived EVs (bdEVs) spectroscopic signatures with AD discriminatory potential. Methods: Herein, FTIR spectra of bdEVs from two biofluids (serum and plasma) and distinct sets of Controls and AD cases were acquired, and EVs’ spectra analyzed. Results: Analysis of bdEVs second derivative peaks area revealed differences between Controls and AD cases in distinct spectra regions, assigned to carbohydrates and nucleic acids, amides, and lipids. Conclusions: EVs' spectroscopic profiles presented AD discriminatory value, supporting the use of bdEVs combined with FTIR as a screening or complementary tool for AD diagnosis.