Pages 1159-1172
Review
José Wagner Leonel Tavares-Júnior, Gabriella Cunha Vieira Ciurleo, Esther de Alencar Araripe Falcão Feitosa, Reinaldo B. Oriá, Pedro Braga-Neto
The Clinical Aspects of COVID and Alzheimer’s Disease: A Round-Up of Where Things Stand and Are Headed
Abstract: The link between long COVID-19 and brain/cognitive impairments is concerning and may foster a worrisome worldwide emergence of novel cases of neurodegenerative diseases with aging. This review aims to update the knowledge, crosstalk, and possible intersections between the Post-COVID Syndrome (PCS) and Alzheimer’s disease (AD). References included in this review were obtained from PubMed searches conducted between October 2023 and November 2023. PCS is a very heterogenous and poorly understood disease with recent evidence of a possible association with chronic diseases such as AD. However, more scientific data is required to establish the link between PCS and AD.

Pages 1173-1186
Systematic Review
Baoqi Zeng*, Chunbian Tang*, Junjian Wang, Qingqing Yang, Qingcuo Ren, Xiaozhi Liu *These authors contributed equally to this work.
Pharmacologic and Nutritional Interventions for Early Alzheimer's Disease: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials
Abstract: Background: Early intervention is essential for meaningful disease modification in Alzheimer's disease (AD). Objective: We aimed to determine the efficacy and safety of pharmacologic and nutritional interventions for early AD. Methods: PubMed, Embase, the Cochrane Library, and ClinicalTrials.gov were searched from database inception until 1 September 2023. We included randomized controlled trials that evaluated the efficacy of interventions in early AD. Only interventions that demonstrated efficacy compared to placebo were included in the network meta-analysis (NMA). Then we performed frequentist fixed-effects NMA to rank the interventions. GRADE criteria were used to evaluate the level of evidence. Results: Fifty-eight trials including a total of 33,864 participants and 48 interventions were eligible for inclusion. Among the 48 interventions analyzed, only 6 (12.5%) treatments—ranging from low to high certainty—showed significant improvement in cognitive decline compared to placebo. High certainty evidence indicated that donanemab (standardized mean difference [SMD] -0.239, 95% confidence interval [CI] -0.343 to -0.134) and lecanemab (SMD -0.194, 95% CI -0.279 to -0.108) moderately slowed the clinical progression in patients with amyloid pathology. Additionally, methylphenidate, donepezil, LipiDiDiet, and aducanumab with low certainty showed significant improvement in cognitive decline compared to placebo. However, there was no significant difference in serious adverse events as reported between the six interventions and placebo. Conclusions: Only 12.5% of interventions studied demonstrated efficacy in reducing cognitive impairment in early AD. Donanemab and lecanemab have the potential to moderately slow the clinical progression in patients with amyloid pathology. Further evidence is required for early intervention in AD.

Pages 1187-1205
Hypothesis
Andrea Slachevsky, Fabrissio Grandi, Daniela Thumala, Sandra Baez, Hernando Santamaria-García, Maureen Schmitter-Edgecombe, Mario A Parra
A Multidimensional, Person-Centered Framework for Functional Assessment in Dementia: Insights from the 'What', 'How', 'To Whom', and 'How Much' Questions
Abstract: Dementia is a syndrome characterized by cognitive and neuropsychiatric symptoms associated with progressive functional decline (FD). FD is a core diagnostic criterion for dementia, setting the threshold between its prodromal stages and the full-blown disease. The operationalization of FD continues to generate a great deal of controversy. For instance, the threshold of FD for the diagnosis of dementia varies across diagnostic criteria, supporting the need for standardization of this construct. Moreover, there is a need to reconsider how we are measuring FD to set boundaries between normal aging, mild cognitive impairment, and dementia. In this paper, we propose a multidimensional framework that addresses outstanding issues in the assessment of FD: i) What activities of daily living (ADLs) are necessary to sustain an independent living in aging? ii) How to assess FD in individuals with suspected neurocognitive disorders? iii) To whom is the assessment directed? and iv) How much does FD differentiate healthy aging from mild and major neurocognitive disorders? Importantly, the To Whom Question introduces a person-centered approach that regards patients and caregivers as active agents in the assessment process of FD. Thus, once impaired ADLs have been identified, patients can indicate how significant such impairments are for them in daily life. We envisage that this new framework will guide future strategies to enhance functional assessment and treatment of patients with dementia and their caregivers.

Pages 1207-1215
Short Communication
Naomi Louisa Paula Starmans, Laurens Jaap Kappelle, Majon Muller, Julie Staals, Charlotte Elisabeth Teunissen, Geert Jan Biessels, Wiesje Maria van der Flier, Frank Johannes Wolters, on behalf of the Heart-Brain Connection Consortium
Blood Pressure Variability and Plasma Biomarkers of Neuronal Injury and Alzheimer’s Disease: A Clinic-Based Study of Patients with Diseases Along the Heart-Brain Axis
Abstract: Higher blood pressure variability (BPV) predisposes to cognitive decline. To investigate underlying mechanisms, we measured 24-h ambulatory BPV, nocturnal dipping and orthostatic hypotension in 518 participants with vascular cognitive impairment, carotid occlusive disease, heart failure, or reference participants. We determined cross-sectional associations between BPV indices and plasma biomarkers of neuronal injury (neurofilament light chain) and Alzheimer’s disease (phosphorylated-tau-181 and Aβ42/Aβ40). None of the BPV indices were significantly associated with any of the biomarkers. Hence, in patients with diseases along the heart-brain axis, we found no evidence for an association between BPV and selected markers of neuronal injury or Alzheimer’s disease.

Pages 1217-1220
Commentary
Ismaeel Yunusa
Pimavanserin's Safety Profile: Insights from a Phase 3b Clinical Trial
Abstract: The recent Alva et al. Phase 3b study on pimavanserin use in older adults with neurodegenerative diseases (NDDs), specifically including Alzheimer’s disease, vascular dementia, Parkinson’s disease (with or without dementia), frontotemporal dementia, and dementia with Lewy bodies, provides important new data on its safety for managing neuropsychiatric symptoms in this population. This commentary on the study further examines the findings within the broader context of antipsychotic therapy as it has evolved from chlorpromazine to pimavanserin in a continuous search for greater safety. Comparing pimavanserin's safety and efficacy profile with historical data and regulatory milestones provides a nuanced perspective for clinicians regarding the significance of the drug’s known advantages over prior antipsychotic treatments. More research is needed to determine the full potential of pimavanserin to improve neuropsychiatric symptoms in older adults with NDDs.

Pages 1221-1223
Commentary
Andrzej W. Przybyszewski, Artur Chudzik
How to Cure Alzheimer’s Disease
Abstract: There has been a lot of buzz surrounding new drug discoveries that claim to cure Alzheimer's disease (AD). However, it is crucial to keep in mind that the changes in the brain linked to AD start occurring 20-30 years before the first symptoms arise. By the time symptoms become apparent, many areas of the brain have already been affected. That's why experts are focusing on identifying the onset of the neurodegeneration processes to prevent or cure AD effectively. Scientists use biomarkers and machine learning methods to analyze AD progressions and estimate them "backward" in time to discover the beginning of the disease.

Pages 1225-1234
Nicola Churchill, Deborah E. Barnes, Mina Habib, Roch A. Nianogo
Forecasting the 20-Year Incidence of Dementia by Socioeconomic Status, Race/Ethnicity, and Region Based on Mid-Life Risk Factors in a U.S. Nationally Representative Sample
Abstract: Background: Alzheimer’s disease and related dementias (ADRD) incidence varies based on demographics, but mid-life risk factor contribution to this variability requires more research. Objective: The purpose of this study is to forecast the 20-year incidence of dementia in the U.S. overall and stratified by race/ethnicity, socioeconomic status (SES), and U.S. geographic region given prior mid-life risk factor prevalence and to examine the extent to which risk factor differences 20 years ago may explain current SES, race/ethnicity, or regional disparities in dementia incidence. Methods: We applied the Cardiovascular Risk Factors, Aging, and Incidence of Dementia (CAIDE) prediction model to the 2006 wave of the Health and Retirement Study (HRS) in participants aged 45 to 64 to estimate the 20-year risk of incident ADRD. Results: The 20-year risk of dementia among middle-aged Americans was 3.3% (95% CI: 3.2%, 3.4%). Dementia incidence was forecast to be 1.51 (95% CI: 1.32, 1.71) and 1.27 (95% CI: 1.14, 1.44) times that in Hispanic and Non-Hispanic Black individuals respectively compared statistically to Non-Hispanic White individuals given mid-life risk factors. There was a progressive increase in dementia risk from the lowest versus highest SES quintile. For geographic region, dementia incidence was forecast to be 1.17 (95% CI: 1.06, 1.30) and 1.27 (95% CI: 1.14, 1.43) times that in Midwestern and Southern individuals respectively compared statistically to Western individuals. Conclusions: Some disparities in dementia incidence could be explained by differences in mid-life risk factors and may point toward policy interventions designed to lessen the ADRD disease burden through early prevention.

Pages 1235-1242
Jochen René Thyrian, Melanie Boekholt, Olga Klein, Iris Blotenberg, Stefan Teipel, Ingo Killimann, Wolfgang Hoffmann
Informal Caregivers of People with Dementia in Germany: Psychosocial Characteristics and Unmet Needs
Abstract: Background: Caregivers of people with dementia living at home (CPwDh) are likely to be affected by a range of health problems. However, CPwDh are often regarded as accompanying persons and receive less attention in research and care. Little is known about this population and their needs in Germany. However, better knowledge of CPwDH is needed to design effective interventions. Objective: The objective of this report is to describe the situation of CPwDh and highlight differences based on sex and living situation. Methods: This was a cross-sectional analysis of the psychosocial characteristics of participants in the GAIN trial, a cluster-randomized, controlled intervention trial investigating the effectiveness of a care management program. A total of n=192 CPwDh were recruited in GP offices, memory clinics or through public campaigns in the German federal state of Mecklenburg-Western Pomerania. The inclusion criteria were an age of 18 years or above, being a CPwDh, written informed consent. In a comprehensive digital assessment, psychosocial variables, burden, and care needs were assessed. Results: Partners, women, and people living in the same household represented the majority of caregivers, and their mean number of needs was 8.7. Overall, participants indicated a mild to moderate burden. There are differences in burden based on sex and living situation, with caregivers living with people with dementia showing less burden and different psychosocial demographics. Conclusions: There is a need for interventions to reduce caregivers’ unmet needs in the CPwDh. Such interventions should consider differences in sex and living situation to better address individual caregiver needs.

Pages 1243-1260
Yann Ilboudo, Satoshi Yoshiji, Tianyuan Lu, Guillaume Butler-Laporte, Sirui Zhou, J. Brent Richards (Handling Associate Editor: Manuel Montero-Odasso)
Vitamin D, Cognition, and Alzheimer’s Disease: Observational and Two-Sample Mendelian Randomization Studies
Abstract: Background: Observational studies have found that vitamin D supplementation is associated with improved cognition. Further, recent Mendelian randomization (MR) studies have shown that higher vitamin D levels, 25(OH)D, may protect against Alzheimer’s disease. Thus, it is possible that 25(OH)D may protect against Alzheimer’s disease by improving cognition. Objective: We assessed this hypothesis, by examining the relationship between 25(OH)D levels and seven cognitive measurements. Methods: To mitigate bias from confounding, we performed two-sample MR analyses. We used instruments from three publications: Manousaki et al. (2020), Sutherland et al. (2022), and the Emerging Risk Factors Collaboration/EPIC-CVD/Vitamin D Studies Collaboration (2021). Results: Our observational studies suggested a protective association between 25(OH)D levels and cognitive measures. An increase in the natural log of 25(OH)D by 1 SD was associated with a higher PACC score (BetaPACC score=0.06, 95%CI=(0.04–0.08); p=1.8 x 10-10). However, in the MR analyses, the estimated effect of 25(OH)D on cognitive measures was null. Specifically, per 1 SD increase in genetically estimated natural log of 25(OH)D, the PACC scores remained unchanged in the overall population, (BetaPACC score= -0.01, 95% CI (-0.06 to 0.03); p=0.53), and amongst individuals aged over 60 (BetaPACC score=0.03, 95% CI (-0.028 to 0.08); p=0.35). Conclusions: In conclusion, our MR study found no clear evidence to support a protective role of increased 25(OH)D concentrations on cognitive performance in European ancestry individuals. However, our study cannot entirely dismiss the potential beneficial effect on PACC for individuals over the age of 60.

Pages 1261-1271
Xiuxiu Huang*, Jiaxin Wang*, Shifang Zhang, Xiaoyan Zhao, Ran An, Yue Lan, Ming Yi, Qiaoqin Wan *These authors contributed equally to this work.
Plasma BDNF/Irisin Ratio Associates with Cognitive Function in Older People
Abstract: Background: Reliable blood biomarkers are crucial for early detection and treatment evaluation of cognitive impairment, including Alzheimer’s disease and other dementias. Objective: To examine whether plasma biomarkers and their combination are different between older people with mild cognitive impairment (MCI) and cognitively normal individuals, and to explore their relations with cognitive performance. Methods: This cross-sectional study included 250 older adults, including 124 participants with MCI, and 126 cognitively normal participants. Plasma brain-derived neurotrophic factor (BDNF), irisin and clusterin were measured, and BDNF/irisin ratio was calculated. Global cognition was evaluated by the Montreal Cognitive Assessment. Results: Plasma irisin levels, but not BDNF, were significantly different between MCI group and cognitively normal group. Higher irisin concentration was associated with an increased probability for MCI both before and after controlling covariates. By contrast, plasma BDNF concentration, but not irisin, was linearly correlated with cognitive performance after adjusting for covariates. Higher BDNF/irisin ratios were not only correlated with better cognitive performance, but also associated with lower risks of MCI, no matter whether we adjusted for covariates. Plasma BDNF and irisin concentrations increased with aging, whereas BDNF/irisin ratios remained stable. No significant results of clusterin were observed. Conclusions: Plasma BDNF/irisin ratio may be a reliable indicator which not only reflects the odds of the presence of MCI but also directly associates with cognitive performance.

Pages 1273-1283
Ze-Xin Guo*, Fang Liu*, Fang-Yuan Wang, Ya-Nan Ou, Liang-Yu Huang, Hao Hu, Zhi-Bo Wang, Yan Fu, Pei-Yang Gao, Lan Tan, Jin-Tai Yu *These authors contributed equally to this work.
CAIDE Score, Alzheimer’s Disease Pathology, and Cognition in Cognitively Normal Adults: The CABLE Study
Abstract: Background: Cardiovascular Risk Factors, Ageing and Dementia (CAIDE) risk score serves as a credible predictor of an individual's risk of dementia. However, studies on the link of the CAIDE score to Alzheimer’s disease (AD) pathology are scarce. Objective: To explore the links of CAIDE score to cerebrospinal fluid (CSF) biomarkers of AD as well as to cognitive performance. Methods: In the Chinese Alzheimer's Biomarker and LifestylE (CABLE) study, we recruited 600 cognitively normal participants. Correlations between the CAIDE score and CSF biomarkers of AD as well as cognitive performance were probed through multiple linear regression models. Whether the correlation between CAIDE score and cognitive performance was mediated by AD pathology was researched by means of mediation analyses. Results: Linear regression analyses illustrated that CAIDE score was positively associated with tau-related biomarkers, including pTau (p < 0.001), tTau (p < 0.001), as well as tTau/Aβ42 (p = 0.008), while it was in negative association with cognitive scores, consisting of MMSE score (p < 0.001) as well as MoCA score (p < 0.001). The correlation from CAIDE score to cognitive scores was in part mediated by tau pathology, with a mediation rate varying from 3.2% to 13.2%. Conclusions: A higher CAIDE score, as demonstrated in our study, was linked to more severe tau pathology and poorer cognitive performance, and tau pathology mediated the link of CAIDE score to cognitive performance. Increased dementia risk will lead to cognitive decline through aggravating neurodegeneration.

Pages 1285-1301
Takaya Suganuma, Sena Hatori, Chung-Kuan Chen, Satoshi Hori, Mika Kanuka, Chih-Yao Liu, Chika Tatsuzawa, Masashi Yanagisawa, Yu Hayashi
Caffeoylquinic Acid Mitigates Neuronal Loss and Cognitive Decline in 5XFAD Mice Without Reducing the Amyloid-β Plaque Burden
Abstract: Background: Caffeoylquinic acid (CQA), which is abundant in coffee beans and Centella asiatica, reportedly improves cognitive function in Alzheimer's disease (AD) model mice, but its effects on neuroinflammation, neuronal loss, and the amyloid-β (Aβ) plaque burden have remained unclear. Objective: To assess the effects of a 16-week treatment with CQA on recognition memory, working memory, Aβ levels, neuronal loss, neuroinflammation, and gene expression in the brains of 5XFAD mice, a commonly used mouse model of familial AD. Methods: 5XFAD mice at 7 weeks of age were fed a 0.8% CQA-containing diet for 4 months and then underwent novel object recognition (NOR) and Y-maze tests. The Aβ levels and plaque burden were analyzed by enzyme-linked immunosorbent assay and immunofluorescent staining, respectively. Immunostaining of markers of mature neurons, synapses, and glial cells was analyzed. AmpliSeq transcriptome analysis and quantitative reverse-transcription-polymerase chain reaction were performed to assess the effect of CQA on gene expression levels in the cerebral cortex of the 5XFAD mice. Results: CQA treatment for 4 months improved recognition memory and ameliorated the reduction of mature neurons and synaptic function-related gene mRNAs. The Aβ levels, plaque burden, and glial markers of neuroinflammation seemed unaffected. Conclusions: These findings suggest that CQA treatment mitigates neuronal loss and improves cognitive function without reducing Aβ levels or neuroinflammation. Thus, CQA is a potential therapeutic compound for AD, improving cognitive function via as-yet unknown mechanisms independent of reductions in Aβ or neuroinflammation.

Pages 1303-1316
Rui Xiong*, Binrui Li*, Haitao Yu*, Tianceng Fan, Huiling Yu, Ying Yang, Jian-Zhi Wang, Guilin Pi, Xifei Yang *These authors contributed equally to this work.
Urolithin A Inhibits Anterior Basolateral Amygdala to Ventral Hippocampal CA1 Circuit to Ameliorate Amyloid-β-Impaired Social Ability
Abstract: Background: Anxiety and social withdrawal are highly prevalent among patients with Alzheimer's disease (AD). However, the neural circuit mechanisms underlying these symptoms remain elusive, and there is a need for effective prevention strategies. Objective: This study aims to elucidate the neural circuitry mechanisms underlying social anxiety in AD. Methods: We utilized 5xFAD mice and conducted a series of experiments including optogenetic manipulation, Tandem Mass Tag-labeled proteome analysis, behavioral assessments, and immunofluorescence staining. Results: In 5xFAD mice, we observed significant amyloid-β (Aβ) accumulation in the anterior part of basolateral amygdala (aBLA). Behaviorally, 6-month-old 5xFAD mice displayed excessive social avoidance during social interaction. Concurrently, the pathway from aBLA to ventral hippocampal CA1 (vCA1) was significantly activated and exhibited a disorganized firing patterns during social interaction. By optogenetically inhibiting the aBLA-vCA1 pathway, we effectively improved the social ability of 5xFAD mice. In the presence of Aβ accumulation, we identified distinct changes in the protein network within the aBLA. Following one month of administration of Urolithin A (UA), we observed significant restoration of the abnormal protein network within the aBLA. UA treatment also attenuated the disorganized firings of the aBLA-vCA1 pathway, leading to an improvement in social ability. Conclusions: The aBLA-vCA1 circuit is a vulnerable pathway in response to Aβ accumulation during the progression of AD and plays a crucial role in Aβ-induced social anxiety. Targeting the aBLA-vCA1 circuit and UA administration are both effective strategies for improving the Aβ-impaired social ability.

Pages 1317-1331
Yuek Ling Chai, Lea Strohm, Yanan Zhu, Rachel S.L. Chia, Joyce Ruifen Chong, Danesha Devini Suresh, Li Han Zhou, Heng Phon Too, Saima Hilal, Tomas Radivoyevitch, Edward H. Koo, Christopher P. Chen, Gunnar Heiko Dirk Poplawski
Extracellular Vesicle-Enriched miRNA-Biomarkers Show Improved Utility for Detecting Alzheimer’s Disease Dementia and Medial Temporal Atrophy
Abstract: Background: Emerging diagnostic modalities suggest that miRNA profiles within extracellular vesicles (EVs) isolated from peripheral blood specimens may provide a non-invasive diagnostic alternative for dementia and neurodegenerative disorders. Given that EVs confer a protective environment against miRNA enzymatic degradation, the miRNAs enriched in the EV fraction of blood samples could serve as more stable and clinically relevant biomarkers compared to those obtained from serum. Objective: To compare miRNAs isolated from EVs versus serum in blood taken from Alzheimer’s disease (AD) dementia patients and control cohorts. Methods: We compared 25 AD patients to 34 individuals who exhibited no cognitive impairments (NCI). Subjects were Singapore residents with Chinese heritage. miRNAs purified from serum versus blood-derived EVs were analyzed for associations with AD dementia and medial temporal atrophy detected by magnetic resonance imaging. Results: Compared to serum-miRNAs, we identified almost twice as many EV-miRNAs associated with AD dementia, and they also correlated more significantly with medial temporal atrophy, a neuroimaging marker of AD-brain pathology. We further developed combination panels of serum-miRNAs and EV-miRNAs with improved performance in identifying AD dementia. Dominant in both panels was miRNA-1290. Conclusions: This data indicates that miRNA profiling from EVs offers diagnostic superiority. This underscores the role of EVs as vectors harboring prognostic biomarkers for neurodegenerative disorders and suggests their potential in yielding novel biomarkers for AD diagnosis.

Pages 1333-1348
Cornelis Jan Stam, Willem de Haan
(Handling Associate Editor: Miguel Castelo-Branco)
Network Hyperexcitability in Early-Stage Alzheimer’s Disease: Evaluation of Functional Connectivity Biomarkers in a Computational Disease Model
Abstract: Background: There is increasing evidence from animal and clinical studies that network hyperexcitability (NH) may be an important pathophysiological process and potential target for treatment in early Alzheimer’s disease (AD). Measures of functional connectivity (FC) have been proposed as promising biomarkers for NH, but it is unknown which measure has the highest sensitivity for early-stage changes in the excitation/inhibition balance. Objective: We aim to test the performance of different FC measures in detecting NH at the earliest stage using a computational approach. Methods: We use a whole brain computational model of activity dependent degeneration to simulate progressive AD pathology and NH. We investigate if and at what stage four measures of FC (amplitude envelope correlation corrected [AECc], phase lag index [PLI], joint permutation entropy [JPE] and a new measure: phase lag time [PLT]) can detect early-stage AD pathophysiology. Results: The activity dependent degeneration model replicates spectral changes in line with clinical data and demonstrates increasing NH. Compared to relative theta power as a gold standard the AECc and PLI are shown to be less sensitive in detecting early-stage NH and AD-related neurophysiological abnormalities, while the JPE and the PLT show more sensitivity with excellent test characteristics. Conclusions: Novel FC measures, which are better in detecting rapid fluctuations in neural activity and connectivity, may be superior to well-known measures such as the AECc and PLI in detecting early phase neurophysiological abnormalities and in particular NH in AD. These markers could improve early diagnosis and treatment target identification.

Pages 1349-1359
Zhi Geng*, Yue Wu*, Jiaqiu Liu, Yuqian Zhan, Yibing Yan, Chaoyi Yang, Xuerui Pang, Yi Ji, Manman Gao, Shanshan Zhou, Ling Wei, Panpan Hu, Xingqi Wu, Yanghua Tian, Kai Wang *These authors contributed equally to this work.
A Study on the Effect of Executive Control Network Functional Connection on the Therapeutic Efficacy of Repetitive Transcranial Magnetic Stimulation in Alzheimer’s Disease
Abstract: Background: Alzheimer's disease (AD) is a neurodegenerative disease characterized by brain network dysfunction. Few studies have investigated whether the functional connections between executive control networks (ECN) and other brain regions can predict the therapeutic effect of repetitive transcranial magnetic stimulation (rTMS). Objective: The purpose of this study is to examine the relationship between the functional connectivity (FC) within ECN networks and the efficacy of rTMS. Methods: We recruited AD patients for rTMS treatment. We established an ECN using baseline period fMRI data and conducted an analysis of the ECN's FC throughout the brain. Concurrently, the support vector regression (SVR) method was employed to project post-rTMS cognitive scores, utilizing the connectional attributes of the ECN as predictive markers. Results: The average age of the patients was 66.86±8.44 years, with 8 males and 13 females. Significant improvement on most cognitive measures. We use ECN connectivity and brain region functions in baseline patients as features for SVR model training and fitting. The SVR model could demonstrate significant predictability for changes in Montreal Cognitive Assessment scores among AD patients after rTMS treatment. The brain regions that contributed most to the prediction of the model (the top 10% of weights) were located in the medial temporal lobe, middle temporal gyrus, frontal lobe, parietal lobe and occipital lobe. Conclusions: The stronger the antagonism between ECN and parieto-occipital lobe function, the better the prediction of cognitive improvement; the stronger the synergy between ECN and fronto-temporal lobe function, the better the prediction of cognitive improvement.

Pages 1361-1374
Wenxiao Wang*, Yiru Yang*, Feng Sang, Yaojing Chen, Xin Li, Kewei Chen, Jun Wang, Zhanjun Zhang *These authors contributed equally to this work.
Vascular Risk Factors and Brain Health in Aging: Insights from a Community-Based Cohort Study
Abstract: Background: The aging population and high rates of Alzheimer's disease (AD) create significant medical burdens, prompting a need for early prevention. Targeting modifiable risk factors like vascular risk factors (VRFs), closely linked to AD, may provide a promising strategy for intervention. Objective: This study investigates how VRFs influence cognitive performance and brain structures in a community-based cohort. Methods: In this cross-sectional study, 4,667 participants over 50 years old, drawn from the Beijing Ageing Brain Rejuvenation Initiative project, were meticulously examined. Cognitive function and VRFs (diabetes mellitus, hypertension, hyperlipidemia, obesity, and smoking), were comprehensively assessed through one-to-one interviews. Additionally, a subset of participants (n=719) underwent MRI, encompassing T1-weighted and diffusion-weighted scans, to elucidate gray matter volume and white matter structural network organization. Results: The findings unveil diabetes as a potent detriment to memory, manifesting in atrophy within the right supramarginal gyrus and diminished nodal efficiency and degree centrality in the right inferior parietal lobe. Hypertension solely impaired memory without significant structural changes. Intriguingly, individuals with comorbid diabetes and hypertension exhibited the most pronounced deficits in both brain structure and cognitive performance. Remarkably, hyperlipidemia emerged as a factor associated with enhanced cognition, and preservation of brain structure. Conclusions: This study illuminates the intricate associations between VRFs and the varied patterns of cognitive and brain structural damage. Notably, the synergistic effect of diabetes and hypertension emerges as particularly deleterious. These findings underscore the imperative to tailor interventions for patients with distinct VRF comorbidities, especially when addressing cognitive decline and structural brain changes.

Pages 1375-1383
Ryszard Pluta, Anna Bogucka-Kocka, Jacek Bogucki, Janusz Kocki, Stanisław J. Czuczwar
Apoptosis, Autophagy, and Mitophagy Genes in the CA3 Area in an Ischemic Model of Alzheimer’s Disease with 2-Year Survival
Abstract: Background: Currently, no evidence exists on the expression of apoptosis (CASP3), autophagy (BECN1), and mitophagy (BNIP3) genes in the CA3 area after ischemia with long-term survival. Objective: The goal of the paper was to study changes in above genes expression in CA3 area after ischemia in the period of 6–24 months. Methods: In this study, using quantitative RT-PCR, we present the expression of genes associated with neuronal death in a rat ischemic model of Alzheimer's disease. Results: First time, we demonstrated overexpression of the CASP3 gene in CA3 area after ischemia with survival ranging from 0.5 to 2 years. Overexpression of the CASP3 gene was accompanied by a decrease in the activity level of the BECN1 and BNIP3 genes over a period of 0.5 year. Then, during 1-2 years, BNIP3 gene expression increased significantly and coincided with an increase in CASP3 gene expression. However, BECN1 gene expression was variable, increased significantly at 1 and 2 years and was below control values 1.5 years post-ischemia. Conclusions: Our observations suggest that ischemia with long-term survival induces neuronal death in CA3 through activation of caspase 3 in cooperation with the pro-apoptotic gene BNIP3. This study also suggests that the BNIP3 gene regulates caspase-independent pyramidal neuronal death post-ischemia. Thus, caspase-dependent and -independent death of neuronal cells occur post-ischemia in the CA3 area. Our data suggest new role of the BNIP3 gene in the regulation of post-ischemic neuronal death in CA3. This suggests the involvement of the BNIP3 together with the CASP3 in the CA3 in neuronal death post-ischemia.

Pages 1385-1396
Tao Wang*, Wei Zhang*, Joshua M.A. Maclin, Hua Xu, Bo Hong, Feng Yan, Yuanyuan Liu, Haining He, Huafeng Liang, Chunbo Li, Yiru Fang, Shifu Xiao (Handling Associate Editor: Jin-Tai Yu) *These authors contributed equally to this work.
Novel Panel of Long Noncoding RNAs as Diagnostic Biomarkers for Amnestic Mild Cognitive Impairment in Peripheral Blood
Abstract: Background: Long noncoding RNAs (lncRNAs) regulate the pathogenesis of Alzheimer's disease (AD). Objective: To identify lncRNAs in the peripheral blood as potential diagnostic biomarkers for amnestic mild cognitive impairment. Methods: In the discovery group, a microarray was used to screen for significant differences in lncRNA expression between patients with mild cognitive impairment (MCI) caused by AD and normal controls (NCs) (n = 10; MCI, 5; NC, 5). Furthermore, two analytic groups were assessed (analytic group 1: n = 10; amnestic MCI (aMCI), 5; NC, 5; analytic group 2: n = 30; AD, 10; aMCI, 10; NC, 10) and finalized in the validation group (n = 150; AD, 50; aMCI, 50; NC, 50). In the analytic and validation groups, real-time quantitative reverse-transcription polymerase chain reaction was used to identify differentially expressed lncRNAs between the aMCI and NC groups. Results: We identified 67 upregulated and 220 downregulated lncRNAs among the expression profiles. The panel with lncRNAs T324988, NR_024049, ENST00000567919, and ENST00000549762 displayed the highest discrimination ability between patients with aMCI and NCs. The area under the receiver operating characteristic curve of this combined model was 0.941, with a sensitivity of 92.00% and specificity of 84.00%. Conclusions: This study reports on a panel of four lncRNAs as promising biomarkers to diagnose aMCIs.

Pages 1397-1407
Angéline Galvin, Jacob Krabbe Pedersen, Konstantin G. Arbeev, Mary F. Feitosa, Svetlana Ukraintseva, Shanshan Yao, Anne B. Newman, Kaare Christensen
End of Life Events and Causes of Death in Danish Long-Lived Siblings: Reduced Dementia Risk Compared to Sporadic Long-Livers
Abstract: Background: Better physical robustness and resilience of long-lived siblings compared to sporadic long-livers has been demonstrated in several studies. However, it is unknown whether long-lived siblings also end their lives better. Objective: To investigate end-of-life (EoL) events (dementia diagnosis, medication, hospitalizations in the last 5 years of life), causes of death, and location of death in long-lived siblings compared to matched sporadic long-livers from the Danish population. Methods: Long-lived siblings were identified through three nationwide Danish studies in which the inclusion criteria varied, but 99.5% of the families had at least two siblings surviving to age 90+. Those who died between 2006 and 2018 were included, and randomly matched with sex, year-of-birth and age-at-death controls (i.e., sporadic long-lived controls) from the Danish population. Results: A total of 5,262 long-lived individuals were included (1,754 long-lived siblings, 3,508 controls; 63% women; median age at death 96.1). Long-lived siblings had a significantly lower risk of being diagnosed with dementia in the last years of life (p=0.027). There was no significant difference regarding the number of prescribed drugs, hospital stays, days in hospital, and location of death. Compared to controls, long-lived siblings presented a lower risk of dying from dementia (p=0.020) and ill-defined conditions (p=0.030). Conclusions: In many aspects long-lived siblings end their lives similar to sporadic long-livers, with the important exception of lower dementia risk during the last 5 years of life. These results suggest that long-lived siblings are excellent candidates for identifying environmental and genetic protective factors of dementia.

Pages 1409-1423
Philipp Wegner, Helena Balabin, Mehmet Can Ay, Sarah Bauermeister, Lewis Killin, John Gallacher, Martin Hofmann-Apitius, Yasamin Salimi, for the Alzheimer's Disease Neuroimaging Initiative, the Japanese Alzheimer’s Disease Neuroimaging Initiative, for the Aging Brain: Vasculature, Ischemia, and Behavior Study, the Alzheimer's Disease Repository Without Borders Investigators, for the European Prevention of Alzheimer’s Disease (EPAD) Consortium
Semantic Harmonization of Alzheimer’s Disease Datasets Using AD-Mapper
Abstract: Background: Despite numerous past endeavors for the semantic harmonization of Alzheimer’s disease (AD) cohort studies, an automatic tool has yet to be developed. Objective: As cohort studies form the basis of data-driven analysis, harmonizing them is crucial for cross-cohort analysis. We aimed to accelerate this task by constructing an automatic harmonization tool. Methods: We created a common data model (CDM) through cross-mapping data from 20 cohorts, three CDMs, and ontology terms, which was then used to fine-tune a BioBERT model. Finally, we evaluated the model using three previously unseen cohorts and compared its performance to a string-matching baseline model. Results: Here, we present our AD-Mapper interface for automatic harmonization of AD cohort studies, which outperformed a string-matching baseline on previously unseen cohort studies. We showcase our CDM comprising 1218 unique variables. Conclusions: AD-Mapper leverages semantic similarities in naming conventions across cohorts to improve mapping performance.

Pages 1425-1440
Stephen Hermes, Janet Cady, Steven Armentrout, James O'Connor, Sarah Carlson Holdaway, Carlos Cruchaga, Thomas Wingo, Ellen McRae Greytak, Alzheimer’s Disease Neuroimaging Initiative (Handling Associate Editor: Charles Murchison)
Epistatic Features and Machine Learning Improve Alzheimer’s Disease Risk Prediction Over Polygenic Risk Scores
Abstract: Background: Polygenic risk scores (PRS) are linear combinations of genetic markers weighted by effect size that are commonly used to predict disease risk. For complex heritable diseases such as late-onset Alzheimer’s disease (LOAD), PRS models fail to capture much of the heritability. Additionally, PRS models are highly dependent on the population structure of the data on which effect sizes are assessed and have poor generalizability to new data. Objective: The goal of this study is to construct a paragenic risk score that, in addition to single genetic marker data used in PRS, incorporates epistatic interaction features and machine learning methods to predict risk for LOAD. Methods: We construct a new state-of-the-art genetic model for risk of Alzheimer's disease. Our approach innovates over PRS models in two ways: First, by directly incorporating epistatic interactions between SNP loci using an evolutionary algorithm guided by shared pathway information; and second, by estimating risk via an ensemble of non-linear machine learning models rather than a single linear model. We compare the paragenic model to several PRS models from the literature trained on the same dataset. Results: The paragenic model is significantly more accurate than the PRS models under 10-fold cross-validation, obtaining an AUC of 83% and near-clinically significant matched sensitivity/specificity of 75%. It remains significantly more accurate when evaluated on an independent holdout dataset and maintains accuracy within APOE genotype strata. Conclusions: Paragenic models show potential for improving disease risk prediction for complex heritable diseases such as LOAD over PRS models.

Pages 1441-1453
Moto Nakaya, Noriko Sato, Hiroshi Matsuda, Norihide Maikusa, Miho Ota, Yoko Shigemoto, Daichi Sone, Tensho Yamao, Yukio Kimura, Tadashi Tsukamoto, Yuma Yokoi, Masuhiro Sakata, Osamu Abe
Assessment of Gray Matter Microstructural Alterations in Alzheimer’s Disease by Free Water Imaging
Abstract: Background: Cortical neurodegenerative processes may precede the emergence of disease symptoms in patients with Alzheimer’s disease (AD) by many years. No study has evaluated the free water of patients with AD using gray matter-based spatial statistics. Objective: The aim of this study was to explore cortical microstructural changes within the gray matter in AD by using free water imaging with gray matter-based spatial statistics. Methods: Seventy-one participants underwent multi-shell diffusion magnetic resonance imaging, 11C-Pittsburgh compound B positron emission tomography, and neuropsychological evaluations. The patients were divided into two groups: healthy controls (n = 40) and the AD spectrum group (n = 31). Differences between the groups were analyzed using voxel-based morphometry, diffusion tensor imaging, and free water imaging with gray matter-based spatial statistics. Results: Voxel-based morphometry analysis revealed gray matter volume loss in the hippocampus of patients with AD spectrum compared to that in controls. Furthermore, patients with AD spectrum exhibited significantly greater free water, mean diffusivity, and radial diffusivity in the limbic areas, precuneus, frontal lobe, temporal lobe, right putamen, and cerebellum than did the healthy controls. Overall, the effect sizes of free water were greater than those of mean diffusivity and radial diffusivity, and the larger effect sizes of free water were thought to be strongly correlated with AD pathology. Conclusions: This study demonstrates the utility of applying voxel-based morphometry, gray matter-based spatial statistics, free water imaging and diffusion tensor imaging to assess AD pathology and detect changes in gray matter.

Pages 1455-1471
Stephanie Van Asbroeck, Sebastian Köhler, Sophie C.P.M. Wimmers, Jean W.M. Muris, Martin P.J. van Boxtel, Kay Deckers (Handling Associate Editor: Mariagnese Barbera)
Multidomain Dementia Risk Reduction in Primary Care Is Feasible: A Proof-Of-Concept Study
Abstract: Background: Dementia risk reduction is a public health priority, but interventions that can be easily implemented in routine care are scarce. Objective: To evaluate the feasibility of integrating dementia risk reduction in regular consultations in primary care and the added value of a dedicated smartphone app (‘MyBraincoach’). Methods: 188 participants (40-60 years), with modifiable dementia risk factors were included from ten Dutch general practices in a cluster-randomized trial (NL9773, 06/10/2021). Practices were randomly allocated (1:1) to provide a risk-reduction consultation only or to additionally provide the app. During the consultation, participants learned about dementia risk reduction and how to improve their risk profile. The app group received daily microteaching-notifications about their personally relevant risk factors. Feasibility was evaluated after 3 months using questionnaires assessing knowledge on dementia risk reduction and health behavior change. The primary outcome was change in the validated “LIfestyle for BRAin health” (LIBRA) score. In-depth interviews were conducted with participants and primary care providers (PCPs). Results: The interventions were positively perceived, with 72.0% finding the consultation informative and 69.2% considering the app useful. Drop-out was low (6.9%). LIBRA improved similarly in both groups, as did Mediterranean diet adherence and body mass index. Knowledge of dementia risk reduction increased, but more in the app group. Interviews provided insight in participants’ and PCPs’ needs and wishes. Conclusions: Integrating dementia risk reduction in primary care, supported by a smartphone app, is a viable approach towards dementia risk reduction. Larger trials are needed to establish (cost-)effectiveness.

Pages 1473-1484
Amanda Zhao, Laura J. Balcer, Jayandra J. Himali, Adrienne O’Donnell, Yashar Rahimpour, Charles DeCarli, Mitzi M. Gonzales, Hugo J. Aparicio, Jaime Ramos-Cejudo, Rachel Kenney, Alexa Beiser, Sudha Seshadri, Joel Salinas
Association of Loneliness with Functional Connectivity MRI, Amyloid-β PET, and Tau PET Neuroimaging Markers of Vulnerability for Alzheimer’s Disease
Abstract: Background: Loneliness has been declared an “epidemic” associated with negative physical, mental, and cognitive health outcomes such as increased dementia risk. Less is known about the relationship between loneliness and advanced neuroimaging correlates of Alzheimer’s disease (AD). Objective: To assess whether loneliness was associated with advanced neuroimaging markers of AD using neuroimaging data from Framingham Heart Study (FHS) participants without dementia Methods: In this cross-sectional observational analysis, we used functional connectivity MRI (fcMRI), amyloid-β (Aβ) PET, and tau PET imaging data collected between 2016 and 2019 on eligible FHS cohort participants. Loneliness was defined as feeling lonely at least one day in the past week. The primary fcMRI marker was Default Mode Network intra-network connectivity. The primary PET imaging markers were Aβ deposition in precuneal and FLR (frontal, lateral parietal and lateral temporal, retrosplenial) regions, and tau deposition in the amygdala, entorhinal, and rhinal regions. Results: Of 381 participants (mean age 58 [SD 10]) who met inclusion criteria for fcMRI analysis, 5% were classified as lonely (17/381). No association was observed between loneliness status and network changes. Of 424 participants (mean age 58 [SD=10]) meeting inclusion criteria for PET analyses, 5% (21/424) were lonely; no associations were observed between loneliness and either Aβ or tau deposition in primary regions of interest. Conclusions: In this cross-sectional study, there were no observable associations between loneliness and select fcMRI, Aβ PET, and tau PET neuroimaging markers of AD risk. These findings merit further investigation in prospective studies of community-based cohorts.