On the path to 2025: understanding the Alzheimer's disease continuum

Acute and chronic excitotoxicity in ischemic stroke and late-onset Alzheimer's disease

Stroke and Alzheimer's disease are common neurological disorders and often occur in the same individuals. The comorbidity of the two neurological disorders represents a grave health threat to older populations. This review presents a brief background of the development of novel concepts and their clinical potentials. The activity of glutamatergic N-methyl-D-aspartate receptors and N-methyl-D-aspartate receptor-mediated Ca 2+ influx is critical for neuronal function. An ischemic insult induces prompt and excessive glutamate release and drastic increases of intracellular Ca 2+ mainly via N-methyl-D-aspartate receptors, particularly of those at the extrasynaptic site. This Ca 2+ -evoked neuronal cell death in the ischemic core is dominated by necrosis within a few hours and days known as acute excitotoxicity. Furthermore, mild but sustained Ca 2+ increases under neurodegenerative conditions such as in the distant penumbra of the ischemic brain and early stages of Alzheimer's disease are not immediately toxic, but gradually set off deteriorating Ca 2+ -dependent signals and neuronal cell loss mostly because of activation of programmed cell death pathways. Based on the Ca 2+ hypothesis of Alzheimer's disease and recent advances, this Ca 2+ -activated "silent" degenerative excitotoxicity evolves from years to decades and is recognized as a unique slow and chronic neuropathogenesis. The N-methyl-D-aspartate receptor subunit GluN3A, primarily at the extrasynaptic site, serves as a gatekeeper for the N-methyl-D-aspartate receptor activity and is neuroprotective against both acute and chronic excitotoxicity. Ischemic stroke and Alzheimer's disease, therefore, share an N-methyl-D-aspartate receptor- and Ca 2+ -mediated mechanism, although with much different time courses. It is thus proposed that early interventions to control Ca 2+ homeostasis at the preclinical stage are pivotal for individuals who are susceptible to sporadic late-onset Alzheimer's disease and Alzheimer's disease-related dementia. This early treatment simultaneously serves as a preconditioning therapy against ischemic stroke that often attacks the same individuals during abnormal aging.

The role of semaphorin 3A in the pathogenesis and progression of Alzheimer's disease and other aging-related diseases: A comprehensive review

Aging serves as a pivotal factor in the etiology of numerous diseases, such as Alzheimer's disease (AD), Parkinson's disease, diabetes, osteoarthritis, atherosclerosis and aging-related macular degeneration. Notably, these diseases often interact with AD through various pathways, facilitating the onset or progression of one another. Semaphorin 3 A (Sema3A), a protein that is essential for axonal guidance during neural development, has recently been identified as a novel regulator in the pathogenesis and progression of multiple aging-related diseases. This article provides a comprehensive review of the expression patterns and mechanisms of action of Sema3A in these diseases. Specifically, Sema3A influences the occurrence and development of aging-related diseases by participating in oxidative stress, inflammatory responses, apoptosis, and synaptic plasticity. Therefore, therapeutic strategies targeting Sema3A present promising avenues for delaying the progression of aging-related diseases and offer novel insights and strategies for their treatment.

Value of blood neural cell-derived small extracellular vesicles in the diagnosis and prediction of Alzheimer's disease: A systematic revie

Blood neural cell-derived small extracellular vesicles (sEVs) can directly reflect changes in brain tissue and are easier to obtain than cerebrospinal fluid. This article systematically reviews the alterations of proteins and miRNAs from neural cell-derived sEVs in patients with Alzheimer's disease (AD), and summarizes the biomarkers with clinical diagnostic and predictive value. PubMed, Web of Science, Embase, and Cochrane Library were searched for studies in blood neural cell-derived sEVs in AD patients up to May 2024. According to the inclusion and exclusion criteria, the literature was screened, the information was extracted and the quality was evaluated. Proteins and miRNAs from neural cell-derived sEVs were classified and summarized, focusing on target molecules with high diagnostic and predictive values for AD. A final 34 articles reporting 5601 participants were included. In cross-sectional studies, Aβ- and Tau-related proteins (Aβ42, Aβ42/40, p-S396-Tau, p-Tau181), p-S312-IRS-1, and cathepsin D were increased, conversely, synaptic proteins (neurogranin, synaptotagmin, synaptophysin, synaptopodin, NMDAR2A) and REST were decreased in blood neuron-derived sEVs (NDsEVs) of patients with AD. While miR-29c-3p was increased in blood NDsEVs and glial cell-derived sEVs. Each of these proteins and miRNAs demonstrated high AD diagnostic value. Additionally, blood astrocyte-derived sEVs (ADsEVs) showed increased complement effector proteins and decreased complement regulatory proteins with a moderate diagnostic value. In longitudinal cohort studies, three composite models displayed high predictive efficacy for early AD prediction, and could predict the occurrence of AD within 1-10 years. Therefore, Aβ- and Tau-related proteins, synaptic proteins, and miRNA in blood neural cell-derived sEVs demonstrate high AD diagnostic and predictive values serving as important biomarkers. Especially, synaptic proteins showed significant changes in the early clinical stage, which has early predictive value.

Exploring interdisciplinary perspectives on the implementation of personalized medicine and patient-orchestrated care in Alzheimer's disease: A qualitative study within the ABOARD research project

BackgroundThe concepts of 'personalized medicine' and 'patient-orchestrated care' in Alzheimer's disease (AD) lack standard conceptualization, which presents challenges for collaborative and interdisciplinary care.ObjectiveWe explored the interpretations and perspectives of professionals involved in interdisciplinary work on a large-scale project, "ABOARD", with the aim to implement personalized medicine and patient-orchestrated care in AD.MethodsSemi-structured interviews were conducted with 30 professionals and audio-recorded. Two researchers independently coded the data inductively, followed by a thematic analysis.ResultsAccording to professionals across different disciplinary backgrounds (mean age 45.7 years; 53.3% female), personalized medicine pertains to the relevant options that an individual has, informed by biomedical and psychosocial factors, whereas patient-orchestrated care captures factors relevant to the decision-making process. Professionals differed in their views on patient-orchestrated care regarding its desirability and feasibility. The concepts were viewed as similar by professionals, as both involve personal preferences while ultimately assigning responsibility to the clinician. However, implementation challenges persist, and no thematic differences were found between clinicians and other AD-related professionals.ConclusionsAD professionals have shared interpretations and perspectives on implementation of personalized medicine but differed in their views on patient-orchestrated care. Personal preferences are seen as part of personalized medicine, but not yet reflected in definitions in the AD field and beyond. Critical discussions on the challenges and existing doubts are necessary for both personalized medicine and patient-orchestrated care. Multi-level implementation changes are needed for both concepts, which warrants stakeholder involvement as well as support and resources from the entire AD field.

The whole-brain structural and functional connectome in Alzheimer's disease spectrum: A multimodal Bayesian meta-analysis of graph theoretical characteristics

Alzheimer's disease (AD) spectrum is increasingly recognized as a progressive network-disconnection syndrome. Neuroimaging studies using graph theoretical analysis (GTA) have reported alterations in the topological properties of whole-brain structural and functional connectomes in both preclinical AD and AD patients, though findings remain inconsistent. This study aimed to identify robust changes in multimodal GTA metrics across the AD spectrum through a comprehensive literature search and Bayesian random-effects meta-analyses. The analysis included 53 studies (17 functional and 37 structural), involving 1743 AD patients, 1502 preclinical AD patients, and 1824 healthy controls (HC). Results revealed lower structural network integration (evidenced by higher characteristic path length and/or normalized characteristic path length) and segregation (evidenced by lower clustering coefficient and local efficiency) in AD and preclinical AD patients compared to HC. Functional network segregation was also lower in AD patients, while preclinical AD showed preserved functional topology despite structural changes. Moderator analyses identified potential methodological moderators, including neuroimaging technique, node and edge definitions, and network type, although further validation is needed. These findings support the progressive disconnection hypothesis in the AD spectrum and suggest that structural network alterations may precede functional network changes. Furthermore, the results help clarify inconsistencies in previous studies and highlight the utility of graph-based metrics as biomarkers for staging AD progression.

A six-year risk assessment for dementia and Alzheimer's disease in the general population through immunoprecipitation-mass spectrometry plasma amyloid quantification

BACKGROUND

Identifying individuals at risk for dementia and Alzheimer's disease (AD) in the general population (GP) is increasingly essential due to new diagnostic criteria and opportunities for effective interventions. Plasma-based biomarkers (pBB) offer a promising approach for detecting positive amyloid profile. However, their effectiveness in predicting clinical dementia and AD risk at the GP level remains largely unexplored.

OBJECTIVES

To assess the risk of clinical dementia and AD using pBB amyloid biomarkers in GP using the most up-to-date proteomic techniques.

DESIGN

Case-cohort study randomly selected from a prospective cohort.

SETTING

The three-city community-living study.

PARTICIPANTS

Over 65 years recruited from the electoral rolls of three French cities.

MEASUREMENTS

pBB amyloid levels (Aβ42, Aβ40 and APP669-711) were measured in the plasma using the mass spectrometry-based (IPMS)-Shimadzu modified technology. Patients were monitored for up to 6 years for incident dementia and AD according to DSM-IV and NINCDS/ADRDA criteria. Cox proportional hazard models adjusted for multiple covariables, including age and renal function, were used to estimate hazard ratios.

RESULTS

Plasma samples from 327 participants were analyzed with a mean age 83 years (80-87), 64.8 % females and a median follow-up time of 2.7 years (0.8-4.8) and including 121 incident dementia cases. Our findings indicate that the Aβ42/Aβ40 ratio, along with a composite score that encompasses APP669-711 and Aβ40/Aβ42 ratios, serves as significant predictors of clinical dementia [HR(95 %CI) = 3.52 (1.69-7.32), p-value<0.001 and 4.34 (2.06-9.17), p-value<0.001, respectively] and AD risk over a six-year period, while also accounting for age and sex interactions. Furthermore, elevated Aβ40 levels correlate with an increased risk of developing dementia (HR=2.56, 95 % CI 1.22-5.35, p = 0.01) and AD (HR=2.60, 95 %CI 1.06-6.36, p = 0.04), and our study confirms that Aβ42 concentrations are significantly influenced by renal function.

CONCLUSIONS

This research advances the potential application of plasma amyloid biomarkers for assessing the risk of clinical dementia and AD in the general population within short period of time, positioning it as a valuable tool alongside existing plasma PT217 biomarkers or using ratio of both of them.

Dynamic PET imaging in patients with unilateral carotid occlusion shows lateralized cerebral hypoperfusion, but no amyloid binding

BackgroundCarotid occlusive disease is a risk factor for cognitive decline. A possible underlying etiology is that hemodynamic impairment results in decreased cerebral perfusion, exacerbated amyloid-β accumulation (Aβ) and poorer cognitive performance.ObjectiveWe aimed to determine whether patients with unilateral internal carotid artery (ICA) occlusion have less cerebral perfusion and more Aβ in the ipsilateral than in the contralateral hemisphere, and whether perfusion and Aβ are associated with cognitive functioning.MethodsWe included 20 patients (age 67.2 ± 7.0 years, 8 females, MMSE 29 [27-29]) with unilateral ICA occlusion, which underwent neuropsychological assessment and dynamic 18F-Florbetaben positron emission tomography (PET). Global and regional relative perfusion (R1) and binding potential (BPND) were obtained from the PET-images using a simplified reference tissue model. We performed Wilcoxon signed-rank tests to examine differences between hemispheres within subjects and linear regression to investigate associations with cognitive functioning.ResultsMedian global R1 was 0.911 (0.883-0.950) and global BPND was 0.172 (0.129-0.187). R1 was lower in the hemisphere ipsilateral to the ICA occlusion than in the contralateral hemisphere (0.899 [0.876-0.921] versus 0.935 [0.889-0.970]). BPND did not differ significantly between hemispheres (ipsilateral 0.172 [0.124-0.181] versus contralateral 0.168 [0.137-0.191]). Neither cerebral perfusion nor Aβ burden were associated with cognitive functioning.ConclusionsPatients with unilateral ICA occlusion did not have more Aβ in the ipsilateral hemisphere than in the contralateral hemisphere despite ipsilateral hypoperfusion. Perfusion and Aβ were unrelated to cognitive functioning. This indicates that cognitive impairment in patients with ICA occlusion is not due to exacerbated Aβ accumulation.

Global experience in brain amyloid imaging

Brain amyloid imaging has become a crucial tool in diagnosing and understanding Alzheimer's disease (AD) and related neurodegenerative disorders. The introduction of amyloid positron emission tomography (PET) with [¹¹C]Pittsburgh Compound-B ([¹¹C]PiB) in the early 2000s marked a breakthrough in visualizing amyloid-β (Aβ) deposition in vivo. Subsequent development of ¹⁸F-labeled tracers, such as [¹⁸F]florbetapir, [¹⁸F]flutemetamol, and [¹⁸F]florbetaben, improved accessibility and extended imaging capabilities. However, global adoption remains uneven due to disparities in healthcare infrastructure, costs, and regulatory frameworks. In high-income countries, amyloid PET is increasingly used in clinical workflows, particularly for differentiating atypical dementia cases and selecting patients for anti-amyloid therapies like aducanumab and lecanemab. Despite its high sensitivity and specificity, challenges persist regarding its clinical utility, particularly in cognitively normal individuals with amyloid accumulation. Research is focusing on integrating amyloid PET with other biomarkers-tau PET, cerebrospinal fluid analysis, and plasma assays-to improve diagnostic accuracy. Geographical variations in amyloid PET research and implementation reveal North America and Europe as leaders, while access remains limited in low- and middle-income countries. Efforts such as the Worldwide Alzheimer's Disease Neuroimaging Initiative aim to enhance global standardization and accessibility. Emerging trends in artificial intelligence (AI)-assisted imaging analysis and next-generation tracers promise further improvements. Addressing ethical concerns related to preclinical screening and ensuring equitable access to amyloid PET are critical for optimizing its role in neurology and nuclear medicine worldwide.

Differential Transcriptional Programs Reveal Modular Network Rearrangements Associated with Late-Onset Alzheimer's Disease

Alzheimer's disease (AD) is a complex, genetically heterogeneous disorder. The diverse phenotypes associated with AD result from interactions between genetic and environmental factors, influencing multiple biological pathways throughout disease progression. Network-based approaches offer a way to assess phenotype-specific states. In this study, we calculated key network metrics to characterize the network transcriptional structure and organization in LOAD, focusing on genes and pathways implicated in AD pathology within the dorsolateral prefrontal cortex (DLPFC). Our findings revealed disease-specific coexpression markers associated with diverse metabolic functions. Additionally, significant differences were observed at both the mesoscopic and local levels between AD and control networks, along with a restructuring of gene coexpression and biological functions into distinct transcriptional modules. These results show the molecular reorganization of the transcriptional program occurring in LOAD, highlighting specific adaptations that may contribute to or result from cellular responses to pathological stressors. Our findings may support the development of a unified model for the causal mechanisms of AD, suggesting that its diverse manifestations arise from multiple pathways working together to produce the disease's complex clinical patho-phenotype.

Carbonic anhydrase inhibitors prevent presymptomatic capillary flow disturbances in a model of cerebral amyloidosis

INTRODUCTION

Disturbances in microvascular flow dynamics are hypothesized to precede the symptomatic phase of Alzheimer's disease (AD). However, evidence in presymptomatic AD remains elusive, underscoring the need for therapies targeting these early vascular changes.

METHODS

We employed a multimodal approach, combining in vivo optical imaging, molecular techniques, and ex vivo magnetic resonance imaging, to investigate early capillary dysfunction in C57BL/6-Tg(Thy1-APPSwDutIowa)BWevn/Mmjax (Tg-SwDI) mice without memory impairment. We also assessed the efficacy of carbonic anhydrase inhibitors (CAIs) in preventing capillary flow disturbances.

RESULTS

Our study revealed capillary flow disturbances associated with alterations in capillary morphology, adhesion molecule expression, and amyloid beta (Aβ) load in 9- to 10-month-old Tg-SwDI mice without memory impairment. CAI treatment ameliorated these capillary flow disturbances, enhanced oxygen availability, and reduced Aβ load.

DISCUSSION

These findings underscore the importance of capillary flow disturbances as early biomarkers in presymptomatic AD and highlight the potential of CAIs for preserving vascular integrity in the early stages of AD.

HIGHLIGHTS

Uncovered early capillary dysfunction in a presymptomatic Alzheimer's disease (AD) mouse model. Evidence linking capillary stalls and capillary dysfunction with oxygen delivery issues in AD. Novel use of carbonic anhydrase inhibitors to prevent early capillary flow disturbances in AD.

Amyloid-beta antibody treatment in Alzheimer's disease : An update on recent data and outlook on implementation in clinical routine

Amyloid-beta (Aβ) antibody treatment has emerged as a promising approach for the treatment of Alzheimer's disease (AD), targeting the accumulation of Aβ plaques, which are a hallmark of the disease. This review provides an update on recent clinical trial data, highlighting the efficacy and safety of various antibodies targeting Aβ. Recent trials have demonstrated that certain Aβ antibodies can reduce amyloid plaques and slow cognitive decline in patients with early AD. Key findings from trials of drugs are discussed, including their mechanisms of action, dosing regimens, and observed side effects. The potential for Aβ antibody therapy to be integrated into routine clinical practice is also explored. While Aβ antibody therapy represents a significant advancement in AD treatment, ongoing research is needed to optimize their use and understand their long-term impact. This review underscores the importance of personalized medicine in AD and the need for continued innovation in therapeutic strategies.

Harnessing the potential of long non-coding RNAs in the pathophysiology of Alzheimer's disease

Alzheimer's disease (AD), a diverse neurodegenerative disease, is the leading cause of dementia, accounting for 60-80 % of all cases. The pathophysiology of Alzheimer's disease is unknown, and there is no cure at this time. Recent developments in transcriptome-wide profiling have led to the identification of a number of non-coding RNAs (ncRNAs). Among these, long non-coding RNAs (lncRNAs)-long transcripts that don't seem to be able to code for proteins-have drawn attention because they function as regulatory agents in a variety of biological processes. Recent research suggests that lncRNAs play a role in the pathogenesis of Alzheimer's disease by modulating tau hyperphosphorylation, amyloid production, synaptic impairment, neuroinflammation, mitochondrial dysfunction, and oxidative stress, though their precise effects on the disorder are unknown. The biology and modes of action of the best-characterized lncRNAs in AD will be outlined here, with an emphasis on their possible involvement in the pathophysiology of the disease. As lncRNAs may offer prospective prognostic/diagnostic biomarkers and therapeutic targets for the treatment of AD, a greater comprehension of the molecular processes and the intricate network of interactions in which they are implicated could pave the way for future research.

Heterogeneous brain abnormalities in subjective cognitive decline converge on a common network and their transcriptional signature

INTRODUCTION

Subjective cognitive decline (SCD) is increasingly recognized as closely related to future Alzheimer's disease (AD). Numerous neuroimaging findings in SCD are inconsistent. We tested whether the various findings localize to a common brain network.

METHODS

Using a novel coordinate network mapping approach, we delineated common brain damage networks that were functionally connected to reported neuroimaging findings. We then decoded these common networks using microscale transcriptomic and chemo-architectures and psychological processes.

RESULTS

We enrolled 45 studies comprising 2453 SCD patients and 3017 healthy controls. The identified SCD networks were largely localized in the somatosensory network (SMN) and default mode network (DMN). Both were robust to perturbations of analyzed parameters and in an independent validation dataset. Neurobiology correlation analyses identified some key biological pathways and neurotransmitters linked to these networks.

DISCUSSION

Our findings reconcile heterogeneous neuroimaging abnormalities in SCD and provide a richer neurobiological underpinning, which has implications for understanding patients with SCD.

HIGHLIGHTS

The heterogeneous neuroimaging findings on SCD were reconciled in a coordinate network mapping framework. The SCD-related functional network involves changes in the DMN, while the SCD-related structural network has changes mainly in primary sensory areas. The identified genes in the functional network were predominantly enriched in biological processes related to synaptic structure, calcium ion binding, and cellular metabolism. An ALE meta-analysis was conducted for comparison.

Cellular Prion Protein and Amyloid-β Oligomers in Alzheimer's Disease-Are There Connections?

Alzheimer's disease (AD) is the most common cause of dementia worldwide. Pathological deposits of neurotoxin proteins within the brain, such as amyloid-β and hyperphosphorylated tau tangles, are prominent features in AD. The prion protein (PrP) is involved in neurodegeneration via its conversion from the normal cellular form (PrPC) to the infection prion protein scrapie (PrPSc) form. Some studies indicated that post-translationally modified PrPC isoforms play a fundamental role in AD pathological progression. Several studies have shown that the interaction of Aβ oligomers (Aβos) with the N-terminal residues of the PrPC protein region appears critical for neuronal toxicity. PrPC-Aβ binding always occurs in AD brains and is never detected in non-demented controls, and the binding of Aβ aggregates to PrPC is restricted to the N-terminus of PrPC. In this study, we aimed to gather all of the recent information about the connections between PrPC and AD, with potential clinical implications.

An Update of Salivary Biomarkers for the Diagnosis of Alzheimer's Disease

Alzheimer's disease (AD) is characterized by progressive cognition and behavior impairments. Diagnosing AD early is important for clinicians to slow down AD progression and preserve brain function. Biomarkers such as tau protein and amyloid-β peptide (Aβ) are used to aid diagnosis as clinical diagnosis often lags. Additionally, biomarkers can be used to monitor AD status and evaluate AD treatment. Clinicians detect these AD biomarkers in the brain using positron emission tomography/computed tomography or in the cerebrospinal fluid using a lumbar puncture. However, these methods are expensive and invasive. In contrast, saliva collection is simple, inexpensive, non-invasive, stress-free, and repeatable. Moreover, damage to the brain parenchyma can impact the oral cavity and some pathogenic molecules could travel back and forth from the brain to the mouth. This has prompted researchers to explore biomarkers in the saliva. Therefore, this study provides an overview of the main finding of salivary biomarkers for AD diagnosis. Based on these available studies, Aβ, tau, cholinesterase enzyme activity, lactoferrin, melatonin, cortisol, proteomics, metabolomics, exosomes, and the microbiome were changed in AD patients' saliva when compared to controls. However, well-designed studies are essential to confirm the reliability and validity of these biomarkers in diagnosing and monitoring AD.

Oral Health Status and Factors Associated with Oral Health in Patients with Alzheimer's Disease: A Matched Case-Control Observational Study

Background: Alzheimer's disease (AD) is a chronic neurodegenerative disease, ranking as the seventh leading cause of death in both sexes. There is increasing awareness of the role of chronic periodontal disease and severe tooth loss as a modifiable risk factor for developing AD. The aim of the present observational study was to assess AD patients with non-affected healthy controls in the context of their dental and periodontal health outcomes; additionally, the potential impact of anamnestic factors and lifestyle habits on oral health outcomes was also studied. Methods: A total of n = 41 AD patients receiving treatment at the Department of Psychiatry, University of Szeged, were compared with n = 41 age- and gender-matched controls from individuals seeking dental treatment and from retirement homes (mean age was 83.32 ± 7.82 years). Dental and periodontal status indices were assessed according to World Health Organization (WHO) criteria. Results: Overall, 51.2%, 68.3%, and 87.8% of AD patients received mood stabilizers, drugs for their non-cognitive symptoms and cognitive symptoms, respectively. Severe tooth loss was observed in 43.9% of AD patients and 56.1% of controls, respectively. There were no significant differences among AD patients and controls regarding the dental status indices studied (p > 0.05 for all indicators). AD patients had significantly higher plaque indices (%) (59.06 ± 15.45 vs. 41.35 ± 7.97; p < 0.001), bleeding on probing (BOP%) (62.65 ± 12.00 vs. 40.12 ± 10.86; p < 0.001), pocket depth [PD] (2.63 ± 0.56 vs. 2.29 ± 0.13; p = 0.002) and attachment loss [AL] (2.85 ± 0.79 vs. 2.39 ± 0.41; p = 0.026) values, compared to controls. Smoking (vs. non-smokers; 56.28 ± 12.36 vs. 51.40 ± 13.23, p = 0.038) and consumption of alcohol (vs. non-drinkers; 58.68 ± 9.86 vs. 54.78 ± 14.86, p = 0.040) were associated with higher plaque indices [%], while no similar effects were shown for dental status parameters (p > 0.05). In contrast, coffee intake and vitamin supplement use had no significant effect on dental or periodontal status parameters (p > 0.05 in all cases). Conclusions: The results of our study underscore the substantial treatment needs of AD patients, calling for heightened awareness among dental healthcare professionals.

Association of hippocampal atrophy with tau pathology of temporal regions in preclinical Alzheimer's disease

BACKGROUND

Hippocampal atrophy is linked to memory and cognitive deficits, preceding clinical diagnosis of mild cognitive impairment (MCI) by decades. Morphometry changes in the hippocampal formation (HF) and their relationship to tau deposition in non-demented individuals remains unclear.

OBJECTIVE

To investigate morphometry changes in the HF and their association with tau deposition in a non-demented cohort.

METHODS

Eighty-three subjects from the Alzheimer's Disease Neuroimaging Initiative (ADNI) underwent T1-weighted MRI and Tau-PET scans at baseline and longitudinal follow-up. Participants were divided into amyloid-negative (Aβ-) and amyloid-positive (Aβ+) groups. Hippocampal volume/thickness were measured, and associations with tau deposition in temporal regions were examined using multivariable linear regression.

RESULTS

No significant association was found between the hippocampal volume/thickness and tau deposition of temporal regions for the Aβ- group. For the Aβ+ group, the hippocampal thickness was significantly associated with tau deposition of entorhinal cortex (ERC) for both hemispheres, and temporal pole, inferior temporal, and middle temporal regions for right hippocampi with the longitudinal follow up scans, while no significant association with the baseline scans. It was interesting that there was strong association between the baseline tau deposition of ERC and temporal pole and the longitudinal follow up thickness of left hippocampi, while the associated regions for the right hemisphere were ERC, temporal pole, and inferior temporal regions.

CONCLUSIONS

Hippocampal atrophy may precede cognitive symptoms, with tau deposition in adjacent temporal regions contributing to hippocampal changes. The right HF appears more vulnerable than the left, indicating hemispheric differences in pathology.

Systems-Level Interactome Mapping Reveals Actionable Protein Network Dysregulation Across the Alzheimer's Disease Spectrum

Alzheimer's disease (AD) progresses as a continuum, from preclinical stages to late-stage cognitive decline, yet the molecular mechanisms driving this progression remain poorly understood. Here, we provide a systems-level map of protein-protein interaction (PPI) network dysfunction across the AD spectrum and uncover epichaperomes-stable scaffolding platforms formed by chaperones and co-factors-as central drivers of this process. Using over 100 human brain specimens, mouse models, and human neurons, we show that epichaperomes emerge early, even in preclinical AD, and progressively disrupt multiple PPI networks critical for synaptic function and neuroplasticity. Glutamatergic neurons, essential for learning and memory, exhibit heightened vulnerability, with their dysfunction driven by protein sequestration into epichaperome scaffolds, independent of changes in protein expression. Notably, pharmacological disruption of epichaperomes with PU-AD restores PPI network integrity and reverses synaptic and cognitive deficits, directly linking epichaperome-driven network dysfunction to AD pathology. These findings establish epichaperomes as key mediators of molecular collapse in AD and identify network-centric intervention strategies as a promising avenue for disease-modifying therapies.

The Use and Understanding of Mild Cognitive Impairment in Routine Specialist Care: A Survey Among German Memory Clinics

Objectives: Mild cognitive impairment (MCI) is a heterogeneous clinical syndrome and is important for the diagnosis and management of Alzheimer's disease (AD). With the expansion of biomarker-based diagnostics, the aim of this study is to clarify the current attitudes towards and the use of MCI, and MCI due to AD, in German memory clinics. Methods: An online survey (50 items) was performed in 2022 among specialized clinicians (N = 45) in German memory clinics to assess the use of MCI and biomarkers in current diagnosis and treatment. Attitudinal and frequency items were assessed with a five-point numeric scale (strongly disagree = 1 to completely agree = 5 and never = 1 to always = 5, respectively). Results: All respondents used MCI as a clinical diagnosis. The benefits of diagnosing MCI were labeling deficits as disease symptoms (M = 4.4, SD = 0.7), improving coping with symptoms (M = 4.1, SD = 0.9), and motivating risk reduction activities (M = 4.0, SD = 0.9). Overall, 37 respondents used specialized diagnostic criteria for MCI due to AD, and all had access to biomarker diagnostics. Patients with MCI due to AD received more frequent counseling on memory training (p < 0.001), other non-pharmacological treatments (p < 0.001), and antidementive drug treatment (p < 0.001) than patients with MCI of other etiologies. Acetylcholinesterase inhibitors were prescribed significantly more frequently to patients with MCI due to AD (p < 0.001) compared to other MCI patients. Conclusions: MCI is commonly used as a clinical diagnosis in German memory clinics. AD biomarker assessment is well established and influences patient counseling and treatment recommendations.

Agreement of cerebrospinal fluid biomarkers and amyloid-PET in a multicenter study

Core Alzheimer's disease (AD) cerebrospinal fluid (CSF) biomarkers have shown incomplete agreement with amyloid-positron emission tomography (PET). Our goal was to analyze the agreement between AD CSF biomarkers and amyloid-PET in a multicenter study. Retrospective multicenter study (5 centers). Participants who underwent both CSF biomarkers and amyloid-PET scan within 18 months were included. Clinical diagnoses were made according to latest diagnostic criteria by the attending clinicians. CSF Amyloid Beta1-42 (Aβ1-42, A), phosphorliated tau 181 (pTau181, T) and total tau (tTau, N) biomarkers were considered normal (-) or abnormal ( +) according to cutoffs of each center. Amyloid-PET was visually classified as positive/negative. Agreement between CSF biomarkers and amyloid-PET was analyzed by overall percent agreement (OPA). 236 participants were included (mean age 67.9 years (SD 9.1), MMSE score 24.5 (SD 4.1)). Diagnoses were mild cognitive impairment or dementia due to AD (49%), Lewy body dementia (22%), frontotemporal dementia (10%) and others (19%). Mean time between tests was 5.1 months (SD 4.1). OPA between single CSF biomarkers and amyloid-PET was 74% for Aβ1-42, 75% for pTau181, 73% for tTau. The use of biomarker ratios improved OPA: 87% for Aβ1-42/Aβ1-40 (n = 155), 88% for pTau181/Aβ1-42 (n = 94) and 82% for tTau/Aβ1-42 (n = 160). A + T + N + cases showed the highest agreement between CSF biomarkers and amyloid-PET (96%), followed by A-T-N- cases (89%). Aβ1-42/Aβ1-40 was a better marker of cerebral amyloid deposition, as identified by amyloid tracers, than Aβ1-42 alone. Combined biomarkers in CSF predicted amyloid-PET result better than single biomarkers.

Neuropsychiatric Symptoms and Mortality in Cognitively Normal Older Mexican Americans

Neuropsychiatric symptoms (NPS) present in older adults with Alzheimer's disease (AD) and other dementias are related to mortality. Research on the relationship between NPS and mortality in a non-dementia population is limited. This study examines NPS as a predictor of six-year mortality among community dwelling Mexican Americans aged 80 years and older. Data included 466 cognitively normal participants from Wave 7 of the Hispanic Established Population for the Epidemiological Study of Elderly. NPS were measured using the Neuropsychiatric inventory (NPI). Cox proportional hazard models were used to estimate the hazard ratio (HR) of mortality. The HR of death at 6 years was 1.02 (95% Confidence Interval-CI [1.00, 1.04]) as a function of NPI score and 1.09 (95% CI [1.02, 1.17]) for the number of NPI conditions, controlling for demographic and health characteristics. Apathy, irritability, and aberrant motor behavior were all independently predictors of mortality. NPS may be modifiable risk factors to increase survival time or may be indicative of underlying health problems. NPS may be related to underlying health conditions among older adults with normal cognitive functioning.

Sequence of decline on the NIH-toolbox cognitive battery in a predominantly Latino sample with autosomal dominant Alzheimer's disease

BACKGROUND

Understanding the sequential progression of cognitive decline in autosomal dominant Alzheimer's disease (ADAD) in the Latino population is crucial for enhancing early identification for targeted interventions. Given the tablet-based administration and increasing frequency of use in epidemiological research, validating this progression within the NIH Toolbox cognitive battery (NIHTB-CB) is important.

OBJECTIVE

The first aim was to utilize an innovative Event-Based Modeling (EBM) analytic approach to estimate the sequence of cognitive declines in persons at risk for ADAD enriched for being of Latino origin. The second aim was to examine associations between EBM-derived estimates of cognitive disease severity and independent cognitive outcomes within carriers and noncarriers.

METHODS

This cross-sectional observational study (N = 30) included 16 ADAD mutation carriers and 14 noncarriers who completed the NIHTB-CB in their primary language (n = 8 Spanish; n = 22 English). An EBM was constructed to compare ADAD mutation carriers and noncarriers on NIHTB-CB performance. We utilized linear regression to examine the associations between the EBM-derived cognitive-decline disease stage and independent outcomes (e.g., performance on the Cognitive Abilities Screening Instrument (CASI) and estimated years to dementia diagnosis).

RESULTS

The EBM estimated that tests assessing episodic memory were the first to become abnormal in the sequence of ADAD-related cognitive decline. Each higher estimated cognitive-decline disease stage was associated with approximately a three-point decline in the CASI and two years closer to dementia diagnosis.

CONCLUSIONS

Findings support the EBM applied to the tablet-based NIHTB-CB to estimate the likely progression of cognitive decline in Latinos with ADAD.

Unveiling the hippocampal subfield changes across the Alzheimer's disease continuum: a systematic review of neuroimaging studies

Studies exploring the hippocampal subfield atrophy in Alzheimer's disease (AD) have shown contradictory results. This review aims to disentangle such heterogeneity by investigating the dynamic changes of hippocampal subfields across the AD continuum. We systematically searched the PubMed and EMBASE databases for case-control studies. Selected studies included investigations of biomarker-based amyloid status and reported data on hippocampal subfield atrophy using advanced MRI techniques. Twelve studies were included. Despite high heterogeneity, a distinguishable pattern of vulnerability of hippocampal subfields can be recognized from the cognitively unimpaired phase to the dementia stage, shedding light on hippocampal changes with disease progression. Consistent findings revealed atrophy in the subiculum and presubiculum, along with a potential increase in volume in the cornu ammonis (CA) among the cognitively unimpaired group, a feature not observed in patients experiencing subjective cognitive decline. Atrophy in the subiculum, presubiculum, CA 1-4, and the dentate gyrus characterized the mild cognitive impairment stage, with a more pronounced severity in the progression to dementia.

Precision Prediction of Alzheimer's Disease: Integrating Mitochondrial Energy Metabolism and Immunological Insights

Alzheimer's disease (AD), a prevalent neurodegenerative disorder, is characterized by mitochondrial dysfunction and immune dysregulation. This study is aimed at developing a risk prediction model for AD by integrating multi-omics data and exploring the interplay between mitochondrial energy metabolism-related genes (MEMRGs) and immune cell dynamics. We integrated four GEO datasets (GSE132903, GSE29378, GSE33000, GSE5281) for differential gene expression analysis, functional enrichment, and weighted gene co-expression network analysis (WGCNA). We identified two key gene modules (turquoise and magenta) significantly correlated with AD. Subsequently, we constructed a risk prediction model incorporating five MEMRGs (MRPL15, RBP4, ABCA1, MPV17, and MRPL37) and clinical factors using LASSO regression. The model demonstrated robust predictive performance (AUC > 0.815) in both internal and external validation (GSE44770) cohorts. Downregulation of MRPL15, RBP4, MPV17, and MRPL37 in AD brain regions (validated using AlzData and qRT-PCR) suggests impaired mitochondrial function. Conversely, ABCA1 upregulation may represent a compensatory response. Furthermore, significant differences in immune cell proportions, particularly gamma delta T cells (p = 0.002) and activated CD4 memory T cells (p = 0.027), were found between AD and non-demented samples. We observed significant correlations between MEMRG expression and specific immune cell fractions, indicating a potential link between mitochondrial dysfunction and immune dysregulation in AD. Our study provides a reliable risk prediction model for AD and highlights the crucial roles of MEMRGs and immune responses in disease pathogenesis, offering potential targets for therapeutic interventions.

Subjective cognitive decline predicts longitudinal neuropsychological test performance in an unsupervised online setting in the Brain Health Registry

BACKGROUNDS

Digital, online assessments are efficient means to detect early cognitive decline, but few studies have investigated the relationship between remotely collected subjective cognitive change and cognitive decline. We hypothesized that the Everyday Cognition Scale (ECog), a subjective change measure, predicts longitudinal change in cognition in the Brain Health Registry (BHR), an online registry for neuroscience research.

METHODS

This study included BHR participants aged 55 + who completed both the baseline ECog and repeated administrations of the CANTAB® Paired Associates Learning (PAL) visual learning and memory test. Both self-reported ECog (Self-ECog) and study partner-reported ECog (SP-ECog), and two PAL scores (first attempt memory score [FAMS] and total errors adjusted [TEA]) were assessed. We estimated associations between multiple ECog scoring outputs (ECog positive [same or above cut-off score], ECog consistent [report of consistent decline in any item], and total score) and longitudinal change in PAL. Additionally we assessed the ability of ECog to identify 'decliners', who exhibited the worst PAL progression slopes corresponding to the fifth percentile and below.

RESULTS

Participants (n = 16,683) had an average age of 69.07 ± 7.34, 72.04% were female, and had an average of 16.66 ± 2.26 years of education. They were followed for an average of 2.52 ± 1.63 visits over a period of 11.49 ± 11.53 months. Both Self-ECog positive (estimate = -0.01, p < 0.001, R²m = 0.56) and Self-ECog consistent (estimate=-0.01, p = 0.002, R²m = 0.56) were associated with longitudinal change in PAL FAMS after adjusting demographics and clinical confounders. Those who were Self-ECog total (Odds ratio [95% confidence interval] = 1.390 [1.121-1.708]) and SP-ECog consistent (2.417 [1.591-3.655]) had higher probability of being decliners based on PAL FAMS.

CONCLUSION

In the BHR's unsupervised online setting, baseline subjective change was feasible in predicting longitudinal decline in neuropsychological tests. Online, self-administered measures of subjective cognitive change might have a potential to predict objective subjective change and identify individuals with cognitive impairments.

A domestic strain of Lactobacillus rhamnosus attenuates cognitive deficit and pro-inflammatory cytokine expression in an animal model of Alzheimer's disease

BACKGROUND

Microbiome dysbiosis plays a significant role in neuroinflammation and Alzheimer's disease (AD). Therefore, gut microbiome restoration using appropriate probiotics may be beneficial in alleviating AD features. In this study, we investigated the effects of a domestic strain of Lactobacillus rhamnosus (L. rhamnosus) on spatial memory, and cytokines expression in an inflammation-based AD model.

METHOD

Male Wistar rats were randomly divided into four groups (six animals per group) of control, L. rhamnosus-only, D-galactose (D-gal)-only, and D-gal + L. rhamnosus. Spatial learning and memory were assessed using the Morris water maze test. IL-1β, IL-6, and TNF-α expression levels were measured using Real-Time qPCR. A significance level of 0.05 was used for statistical analysis.

RESULTS

In contrast to the D-gal + L. rhamnosus-treated group, D-gal only treated group showed impaired memory in MWM test compared to the control group. Additionally, D-gal treatment resulted in an increase in IL-1β and TNF-α levels and a decrease in IL-6 levels, which was not statistically significant. However, the TNF-α level was significantly decreased in D-gal + L. rhamnosus-treated group compared to D-gal-only treated group (P < 0.05). Also, IL-6 level was significantly lower in D-gal + L. rhamnosus-treated group compared to control group (P < 0.05).

CONCLUSION

These results suggest that the domestic L. rhamnosus might positively impact cognitive deficit and neuroinflammation. Further studies are suggested to investigate the specific mechanisms mediating the effects of L. rhamnosus on cognitive functions and neuroinflammation in animal models of AD.

Water-Soluble Ginseng Oligosaccharides Prevent Scopolamine-Induced Cholinergic Dysfunction and Inflammatory Cytokine Overexpression

Cholinergic deficiency and neuroinflammation are the two main factors of Alzheimer's disease. Recent studies have shown that water-soluble ginseng oligosaccharides (WGOS) derived from Panax ginseng roots can protect against scopolamine-induced impairments in learning and memory. However, the fundamental mechanisms remain unclear for the most part. The purpose of this study was to examine the effect of WGOS on cholinergic function and protein levels of proinflammatory cytokines in the hippocampus of mice. Mice were first pretreated with WGOS or saline, and then treated with scopolamine to establish an Alzheimer's disease model. The cognition memory of the mice was assessed through the behavioral test. The effect of WGOS on the cholinergic system was evaluated by measuring acetylcholine (ACh) neurotransmitter concentration and acetylcholinesterase (AChE) activity in the hippocampus. Using ELISA, the inflammatory cytokines IL-1β and TNF-α in the hippocampus were identified. This study found that WGOS treatment prevented the scopolamine-induced impairment of mice's recognition memory, as seen by their enhanced object recognition. In addition, WGOS prevented the scopolamine-induced decrease in ACh concentration and increase in AChE activity. Moreover, WGOS treatment inhibited scopolamine-induced upregulation of the inflammatory proteins IL-1β and TNF-α. These findings suggest that the amelioration of scopolamine-induced cognitive impairment in mice by WGOS was a consequence of the control of cholinergic function and inflammatory response in the hippocampus. Our findings suggest that WGOS should be investigated as a dietary supplement or medication for the treatment of learning and memory disorders in humans.

Mitochondrial Genome Variants and Alzheimer's Disease

Alzheimer's disease (AD), a severe neurodegenerative disease of the central nervous system, is the most common cause of cognitive impairment in people over the age of 60. The etiology and pathogenesis of Alzheimer's disease are still unclear despite decades of active research. Numerous studies have shown that neurodegenerative processes in AD are associated with the mitochondrial dysfunction. In this review, we briefly discuss the results of these studies and present the reported evidence that mitochondrial dysfunction in AD is associated with mitochondrial DNA (mtDNA) variations. The results of association analysis of mtDNA haplogroups and individual polymorphic variants, including those whose combinations define haplogroups, with AD are described in detail. These data clearly indicate the role of variations in the mitochondrial genome in the susceptibility to AD, although the problem of significance of individual mtDNA variants is far from being resolved.

Di Huang Yi Zhi Fang improves cognitive function in APP/PS1 mice by inducing neuronal mitochondrial autophagy through the PINK1-parkin pathway

BACKGROUND

Alzheimer's disease (AD) is an irreversible age-related neurodegenerative condition characterized by the deposition of amyloid-β (Aβ) peptides and neurofibrillary tangles. Di Huang Yi Zhi (DHYZ) formula, a traditional Chinese herbal compound comprising several prescriptions, demonstrates properties that improve cognitive abilities in clinical. Nonetheless, its molecular mechanisms on treating AD through improving neuron cells mitochondria function have not been deeply investigated.

OBJECTIVE

This study administered DHYZ to APP/PS1 mice to explore its potential therapeutic mechanisms in AD treatment.

METHODS

APP/PS1 transgenic mice were given DHYZ (L, M, H), donepezil, or distilled water for a consecutive 12-week period. The Morris water maze test was used to assess memory capacity, transmission electron microscopy was used to observe mitochondrial and synaptic structures, immunohistochemistry and western blot detected proteins involved in the mitochondrial autophagy pathway, ELISA measured serum Aβ content, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assessed neuronal cell apoptosis.

RESULTS

DHYZ demonstrates a notable therapeutic impact on mice with AD, effectively improving cognitive and memory impairments. DHYZ decreases Aβ accumulation in the hippocampus by reducing BACE1 activity and enhancing Aβ clearance through the blood-brain barrier. Additionally, DHYZ significantly suppresses neuronal apoptosis, enhances synaptic structure, and increases synapse numbers, processes strongly linked to the activation of mitochondrial PINK1-Parkin autophagy.

CONCLUSIONS

DHYZ enhances cognitive function in APP/PS1 mice by stimulating neuronal mitochondrial autophagy through the PINK1-Parkin pathway.

A Modality-Flexible Framework for Alzheimer's Disease Diagnosis Following Clinical Routine

Dementia has high incidence among the elderly, and Alzheimer's disease (AD) is the most common dementia. The procedure of AD diagnosis in clinics usually follows a standard routine consisting of different phases, from acquiring non-imaging tabular data in the screening phase to MR imaging and ultimately to PET imaging. Most of the existing AD diagnosis studies are dedicated to a specific phase using either single or multi-modal data. In this paper, we introduce a modality-flexible classification framework, which is applicable for different AD diagnosis phases following the clinical routine. Specifically, our framework consists of three branches corresponding to three diagnosis phases: 1) a tabular branch using only tabular data for screening phase, 2) an MRI branch using both MRI and tabular data for uncertain cases in screening phase, and 3) ultimately a PET branch for the challenging cases using all the modalities including PET, MRI, and tabular data. To achieve effective fusion of imaging and non-imaging modalities, we introduce an image-tabular transformer block to adaptively scale and shift the image and tabular features according to modality importance determined by the network. The proposed framework is extensively validated on four cohorts containing 6495 subjects. Experiments demonstrate that our framework achieves superior diagnostic performance than the other representative methods across various AD diagnosis tasks, and shows promising performance for all the diagnosis phases, which exhibits great potential for clinical application.

Exploring the potential mechanism of Polygonatum sibiricum for Alzheimer's disease based on network pharmacology and molecular docking: An observational study

Alzheimer's disease (AD) is a neurodegenerative disease, and there have been no systematic studies of Polygonatum against Alzheimer's disease. Therefore, our study will elucidate the mechanism of Polygonatum against AD based on network pharmacology and molecular docking. The active ingredients and corresponding targets of Polygonatum were identified using the traditional Chinese medicine systematic pharmacology database and analysis platform. Disease targets of AD were retrieved from the therapeutic target database, Online Mendelian Inheritance in Man, GeneCards, and Disgenet databases. Using the STRING database, we constructed protein interaction networks and performed gene ontology functional enrichment analysis as well as Kyoto encyclopedia of genes and genomes pathway enrichment analysis on common targets. We then drew drug-component-target-pathway-disease network maps using Cytoscape 3.10.1 software and validated the molecular docking using AutoDock4. A total of 10 active ingredients and 108 common targets were screened from Polygonatum, 29 genes (including AKT1 and STAT3) were identified as core genes. According to gene ontology analysis, the core targets were found to be mainly involved in signal transduction, positive regulation of gene expression, negative regulation of the apoptotic process, and so on. The Kyoto encyclopedia of genes and genomes analysis revealed that the signaling pathways comprised pathways in cancer, pathways of neurodegeneration - multiple diseases, and PI3K-Akt signaling pathway. The molecular docking results indicated that 10 of active ingredients from Polygonatum exhibited strong binding affinity with the 6 core targets that were screened before. The activity of Polygonatum against AD could be attributed to the regulation of multiple biological effects via multi-pathways (pathways in cancer, pathways of neurodegeneration - multiple diseases, and PI3K-Akt signaling pathway). The binding activities were estimated as good level by molecular docking. These discoveries disclosed the multi-component, multi-target, and multi-pathway characteristics of Polygonatum against AD, providing a new strategy for such medical problem.

Needs assessment of people living with cognitive impairment/dementia, a requirement of comprehensive psychogeriatric assessment and person-centered care. Empirical validation of the model in a community study

Introduction

Cognitive impairment and dementia are part of a continuum that progressively leads to functional impairment and dependency. Dementia is a paradigmatic example of chronic and complex psychogeriatric diseases, requiring a comprehensive assessment. The authors underline the importance of implementing a formal assessment of needs (whether met or unmet) as an essential element of comprehensive assessment. The aim of this paper is to empirically validate this model of approach towards dementia, the needs assessment, demonstrating the relationship between needs and functionality/dependency in people with cognitive impairment/dementia in the community.

Material and methods

Community-based, cross-sectional, descriptive epidemiological study based on the reanalysis of data from a two-phase community epidemiological study conducted in Santiago de Compostela, Spain, of 800 people over 65 years of age. The present study reanalyzes a subsample of 368 people, including those with dementia/cognitive impairment. The comprehensive assessment of the sample included sociodemographic variables, the presence of chronic diseases, health self-perception, assessment of affective, cognitive and functional state, as well as the needs assessment. The main instruments used were the MMSE, the Geriatric Depression Scale (GDS), the Barthel and Katz Indices, the Lawton Scale, and, for the needs assessment, the Camberwell Assessment of Need for the Elderly (CANE). For the clinical diagnosis of dementia, the ICD-10 criteria were followed. Statistical analysis: A study of the association between variables was carried out through hypothesis testing and a multivariate study was performed using regression models to analyze the relationship between the different variables defining disability/dependency, other health conditions and sociodemographic variables and the MMSE score as an expression of the cognitive impairment/dementia continuum.

Results

People with cognitive impairment/dementia had a higher number of needs compared to the healthy population. The severity of cognitive impairment is a significant predictor of dependency in Basic Activities of Daily Living (BADL) and is also a predictor of a greater number of needs (both met and unmet).

Discussion

The present study provides empirical evidence of the importance of implementing scales to assess the needs of people with cognitive impairment, as part of the process of comprehensive biopsychosocial assessment and person-centered care for dementia.

Carbonic anhydrase inhibitors prevent presymptomatic capillary flow disturbances in a model of cerebral amyloidosis

INTRODUCTION

Disturbances in microvascular flow dynamics are hypothesized to precede the symptomatic phase of Alzheimer's disease (AD). However, evidence in presymptomatic AD remains elusive, underscoring the need for therapies targeting these early vascular changes.

METHODS

We employed a multimodal approach, combining in vivo optical imaging, molecular techniques, and ex vivo MRI, to investigate early capillary dysfunction in Tg-SwDI mice without memory impairment. We also assessed the efficacy of carbonic anhydrase inhibitors (CAIs) in preventing capillary flow disturbances.

RESULTS

Our study revealed capillary flow disturbances associated with alterations in capillary morphology, adhesion molecule expression, and Amyloid-β (Aβ) load in 9-10-month-old Tg-SwDI mice without memory impairment. CAI treatment ameliorated these capillary flow disturbances, enhanced oxygen availability, and reduced Aβ load.

DISCUSSION

These findings underscore the importance of capillary flow disturbances as early biomarkers in presymptomatic AD and highlight the potential of CAIs for preserving vascular integrity in the early stages of AD.

Identification of JAZF1, KNOP1, and PLEKHA1 as causally associated genes and drug targets for Alzheimer's disease: a summary data-based Mendelian randomization study

BACKGROUND

There is a growing body of evidence indicating the significant role of the immune system and immune cells in the progression of Alzheimer's disease (AD). However, the exact role of genes from various immune cell types in AD remains unclear. We aimed to utilize summary data-based Mendelian randomization (SMR) to explore the potential causal relationships between genes in specific immune cells and the risk of AD.

METHODS

By utilizing data sets of expression quantitative trait loci (eQTL) for 14 different immune cell types and large-scale AD genome-wide association study (GWAS), we employed SMR to identify key genes associated with AD within specific immune cells. Sensitivity analyses, including F-statistic, colocalization, and assessment of horizontal pleiotropy, were further conducted to validate the discovered genes. In addition, replication analyses were performed in AD GWAS from the FinnGen consortium. Finally, we further identified existing drugs that target or interact with the druggable genes and reviewed the studies about the associations between these drugs and AD.

RESULTS

SMR analysis revealed 342 genes associated with AD across 14 immune cell types. Further sensitivity analyses identified nine genes, CTSH, FCER1G, FNBP4, HLA-E, JAZF1, KNOP1, PLEKHA1, RP11-960L18.1, and ZNF638 that had significant associations with AD across nine specific immune cell types. JAZF1, KNOP1 and PLEKHA1 were replicated in an independent analysis using the GWAS data. The review on gene-related drugs also supported these findings.

CONCLUSIONS

Our research suggests that the expression of the genes JAZF1, KNOP1, and PLEKHA1 in specific immune cell types is related to the risk of AD.

Ethical issues in genomics research in persons with Alzheimer's Disease/Alzheimer's Disease-related dementia (AD/ADRD): a systematic review

INTRODUCTION

Given the growing number of Alzheimer's Disease and Alzheimer's Disease Related Dementias (AD/ADRD) genomics research projects and the vulnerabilities of study participants, it is critical to evaluate the literature on the ethical challenges in such studies to ensure high ethical standards.

METHODS

We conducted a systematic review of the literature on ethical issues in AD/ADRD genomics research. We searched Embase, PsycINFO, CiNAHL, Scopus, and Ovid Medline for empirical and normative papers published in peer-reviewed journals on the ethical issues involved in conducting genomics research among persons with AD/ADRD. We used ethical principles from an existing framework as a priori codes to categorize the ethical issues and adapted another framework of Dementia Research Ethical Issues (DREI) as subcategories for our synthesis. We used the 2021 PRISMA guidelines to guide our study.

RESULTS

We screened 5,509 papers and included 27 of these papers in the systematic review after deduplication, title, and full-text review. The papers contained 109 ethical issues that were mapped against 42 out of 75 relevant DREIs. The highest number of DREIs were mapped to "respect for persons and communities", "favorable risk-benefit ratio", "informed consent" and "scientific validity". The least mapped principles to the DREIs were "fair participant selection", "independent review", "social value", and "collaborative partnership".

CONCLUSION

Our review showed that there is a dearth of literature on the ethical principles of "fair participant selection", "independent review", "social value" and "collaborative partnership" in genomics research on AD/ADRDs. It is difficult to draw firm conclusions from the distribution of attention paid to specific principles because these may only reflect the concerns of AD/ADRD genomics research ethicists in high-income countries. There is need for more research on the ethics of AD/ADRD genomics research in low and middle-income countries for a more balanced account of the important ethical considerations in this field.

Neurocognitive effects of proanthocyanidin in Alzheimer's disease: a systematic review of preclinical evidence

Cognitive disorders and dementia largely influence individual independence and orientation. Based on the Alzheimer's Disease International (ADI) estimation, approximately 75% of individuals with dementia are undiagnosed. In fact, in some low- and middle-income countries, the percentage is as high as 90%. In this systematic review, which is based on PRISMA guidelines, we aim to identify the mechanism of action of proanthocyanidin. Finding a natural product alternative as a potential nootropic can help increase the number of armamentariums against dementia and other cognitive impairments. In this preclinical research, we determined the effect of proanthocyanidins on Alzheimer's disease (AD) by searching electronic bibliographic databases like Scopus, Proquest, ScienceDirect, PubMed, and Google. There was no imposed time limit. However, the search was limited to only English articles. The review protocol is registered on PROSPERO as CRD42022356301. A population, intervention, control, and outcomes (PICO) technique was utilized for report inclusion, and all reports were assessed for risk of bias by using the SYRCLE's RoB tool. The article's bibliographic information, induction model, type of proanthocyanidins, animal strain/weight/age, and outcome measurements were acquired from ten papers and are reported here. Further analysis was validated and determined for the review. The included studies met the review's inclusion criteria and suggested that proanthocyanidins have a neurocognitive effect against AD. Additionally, the effectiveness of proanthocyanidins in reducing oxidative stress, acetylcholinesterase activity, amyloid beta, its efficacy in alleviating superoxide dismutase, cognitive properties, and in facilitating cholinergic transmission in various models of AD has been collectively observed in ten studies.

Citrus supplementation in subjective cognitive decline: results of a 36-week, randomized, placebo-controlled trial

BACKGROUND

Developing interventions for older adults with subjective cognitive decline (SCD) has the potential to prevent dementia in this at-risk group. Preclinical models indicate that Citrus-derived phytochemicals could benefit cognition and inflammatory processes, but results from clinical trials are still preliminary. The aim of this study is to determine the effects of long-term supplementation with Citrus peel extract on cognitive performance and inflammation in individuals with SCD.

METHODS

Eighty participants were randomly assigned to active treatment (400 mg of Citrus peel extract containing 3.0 mg of naringenin and 0.1 mg of auraptene) or placebo at 1:1 ratio for 36 weeks. The primary endpoint was the change in the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) total score across the 36-week trial period. Other cognitive outcomes included tests and scales evaluating verbal memory, attention, executive and visuospatial functions, and memory concerns. The secondary endpoint was the change of interleukin-8 (IL-8) levels over the 36-week trial period in a subsample of 60 consecutive participants. An Intention-to-treat approach with generalized linear mixed models was used for data analysis.

RESULTS

The RBANS total score showed significant improvement in both Citrus peel extract and placebo groups at 36 weeks (p for time < .001, d = 0.36, p time x treatment = .910). Significant time effects were also found in cognitive domains of short- and long-term verbal memory (p < .001) and scales of subjective memory (p < .01), with no significant time x treatment interaction. The largest effect sizes were observed in verbal memory in the placebo group (d = 0.69 in short-term, and d = 0.78 in long-term verbal memory). Increased IL-8 levels were found at 36-week follow-up in both Citrus peel extract and placebo groups (p for time = .010, d = 0.21, p time x treatment = .772). Adverse events were balanced between groups.

CONCLUSIONS

In this randomized clinical trial, long-term Citrus peel extract supplementation did not show cognitive benefits over placebo in participants with SCD, possibly due to high placebo response. These findings might have specific implications for designing future nutraceutical trials in individuals experiencing SCD.

TRIAL REGISTRATION

The trial has been registered at the United States National Library of Medicine at the National Institutes of Health Registry of Clinical Trials under the code NCT04744922 on February 9th, 2021 ( https://www.

CLINICALTRIALS

gov/ct2/show/NCT04744922 ).

Reducing confusion surrounding expert conceptions of Alzheimer's and dementia: A practical analysis

Biological, clinicobiological and clinical conceptions of Alzheimer's disease and related dementias are being promoted simultaneously to different practical ends. The co-existence of contemporary conceptions and the 'scary label' associated with older diagnostic criteria create the possibility of misunderstanding and harm. In this comment, we argue in favour of socio-ethical interventions targeted to health workers and the general public so as to lower the uncertainties introduced by contemporary diagnostic criteria and to articulate how they relate to established criteria.

The unique role of anosognosia in the clinical progression of Alzheimer's disease: a disorder-network perspective

Alzheimer's disease (AD) encompasses a long continuum from a preclinical phase, characterized by neuropathological alterations albeit normal cognition, to a symptomatic phase, marked by its clinical manifestations. Yet, the neural mechanisms responsible for cognitive decline in AD patients remain poorly understood. Here, we posit that anosognosia, emerging from an error-monitoring failure due to early amyloid-β deposits in the posterior cingulate cortex, plays a causal role in the clinical progression of AD by preventing patients from being aware of their deficits and implementing strategies to cope with their difficulties, thus fostering a vicious circle of cognitive decline.

Effects of hippocampal damage on pain perception in a rat model of Alzheimer's disease induced by amyloid-β and ibotenic acid injection into the hippocampus

Patients with Alzheimer's disease (AD) present with a variety of symptoms, including core symptoms as well as behavioral and psychological symptoms. Somatosensory neural systems are generally believed to be relatively unaffected by AD until late in the course of the disease; however, somatosensory perception in patients with AD is not yet well understood. One factor that may complicate the assessment of somatosensory perception in humans centers on individual variations in pathological and psychological backgrounds. It is therefore necessary to evaluate somatosensory perception using animal models with uniform status. In the current study, we focused on the hippocampus, the primary site of AD. We first constructed a rat model of AD model using bilateral hippocampal injections of amyloid-β peptide 1-40 and ibotenic acid; sham rats received saline injections. The Morris water maze test was used to evaluate memory impairment, and the formalin test (1 % or 4 % formalin) and upper lip von Frey test were performed to compare pain perception between AD model and sham rats. Finally, histological and immunohistochemical methods were used to evaluate tissue damage and neuronal activity, respectively, in the hippocampus. AD model rats showed bilateral hippocampal damage and had memory impairment in the Morris water maze test. Furthermore, AD model rats exhibited significantly less pain-related behavior in phase 2 (the last 50 min of the 60-minute observation) of the 4 % formalin test compared with the sham rats. However, no significant changes were observed in the von Frey test. Immunohistochemical observations of the trigeminal spinal subnucleus caudalis after 4 % formalin injection revealed significantly fewer c-Fos-immunoreactive cells in AD model rats than in sham rats, reflecting reduced neuronal activity. These results indicate that AD model rats with hippocampal damage have reduced responsiveness to persistent inflammatory chemical stimuli to the orofacial region.

Disparities in structural brain imaging in older adults from rural communities in Southern Nevada

Introduction

Identifying the associations between rural-living or neighborhood disadvantage and neurobiology may clarify rural-urban disparities in older adults with cognitive impairment related to Alzheimer's disease.

Methods

We examined rural-urban differences and neighborhood disadvantages in brain cortical thickness (CT) measures among 71 rural and 87 urban-dwelling older adults. Analysis of covariance was used to test each FreeSurfer-derived CT measures' associations with rural-urban living, clinical impairment status, and their interactions. Post-hoc linear regressions were used to test the association between CT measures and neighborhood disadvantage index.

Results

Rural-dwelling older adults had thinner cortices in temporal and inferior frontal regions compared to urban participants, especially among clinically normal participants, where the thinner temporal cortex further correlated with higher neighborhood disadvantage. Conversely, rural participants had thicker cortices in superior frontal, parietal and occipital regions.

Discussion

Our results suggest a complex interplay between community contexts and neurobiology. For memory-related regions, rural-living and neighborhood disadvantage might be negatively associated with subjects' brain structures.

Revolutionizing Alzheimer's Diagnosis and Management: The Dawn of Biomarker-Based Precision Medicine

Alzheimer's disease (AD), a leading cause of dementia, presents a formidable global health challenge intensified by the aging population. This review encapsulates the evolving landscape of AD diagnosis and treatment with a special focus on the innovative role of fluid biomarkers. Pathologically, AD is marked by amyloid beta (Aβ) plaques and neurofibrillary tangles of hyperphosphorylated tau, which lead to synaptic dysfunction, neuronal loss, and cognitive decline. These pathological changes, commencing decades before symptom onset, underscore the need for early detection and intervention. Diagnosis traditionally relies on clinical assessment, neuropsychological testing, and neuroimaging techniques. However, fluid biomarkers in cerebrospinal fluid and blood, such as various forms of Aβ, total tau, phosphorylated tau, and neurofilament light chain, are emerging as less invasive, cost-effective diagnostic tools. These biomarkers are pivotal for early diagnosis, differential diagnosis, disease progression monitoring, and treatment response evaluation. The treatment landscape is shifting toward personalized medicine, highlighted by advancements in Aβ immunotherapies, such as lecanemab and donanemab. Demonstrating efficacy in phase III clinical trials, these therapies hold promise as tailored treatment strategies based on individual biomarker profiles. The integration of fluid biomarkers into clinical practice represents a significant advance in AD management, providing the potential for early and precise diagnosis, coupled with personalized therapeutic approaches. This heralds a new era in combating this debilitating disease.

MAMs and Mitochondrial Quality Control: Overview and Their Role in Alzheimer's Disease

Alzheimer's disease (AD) represents the most widespread neurodegenerative disorder, distinguished by a gradual onset and slow progression, presenting a substantial challenge to global public health. The mitochondrial-associated membrane (MAMs) functions as a crucial center for signal transduction and material transport between mitochondria and the endoplasmic reticulum, playing a pivotal role in various pathological mechanisms of AD. The dysregulation of mitochondrial quality control systems is considered a fundamental factor in the development of AD, leading to mitochondrial dysfunction and subsequent neurodegenerative events. Recent studies have emphasized the role of MAMs in regulating mitochondrial quality control. This review will delve into the molecular mechanisms underlying the imbalance in mitochondrial quality control in AD and provide a comprehensive overview of the role of MAMs in regulating mitochondrial quality control.

Differences in Grey Matter Concentrations and Functional Connectivity between Young Carriers and Non-Carriers of the APOE ε4 Genotype

Background: The pathophysiology of Alzheimer's disease (AD) may begin developing years or even decades prior to the manifestation of its first symptoms. The APOE ε4 genotype is a prominent genetic risk for AD that has been found to be associated with brain changes across the lifespan since early adulthood. Thus, studying brain changes that may occur in young adults with an APOE ε4 status is highly relevant. Objective: Examine potential differences in grey matter (GM) and functional connectivity (FC) in brains of cognitively healthy young APOE ε4 carriers and non-carriers, denoted here as ε4(+) and ε4(-), respectively. Methods: Three Tesla magnetic resonance imaging (MRI) brain scans were acquired from cognitively healthy young participants aged approximately 20 years (n = 151). Voxel-based morphometry (VBM) analysis was employed to identify potential structural differences in GM between ε4(+) and ε4(-). In a subsequent seed-based connectivity (SBC) analysis, brain regions that structurally differed in the VBM analysis were considered as seeds and correlated with all the remaining voxels across the brains to then measure the differences in FC between groups. Results: The VBM analysis suggested that ε4(+) (n = 28) had greater GM densities relative to ε4(-) (n = 123) in the left hippocampus and the left posterior insula (puncorr < 0.001). However, the effect did not survive the correction for multiple comparisons, suggesting minimal structural differences in this age range. In contrast, the SBC analysis indicated that ε4(+) exhibited significantly decreased FC between the left hippocampus and areas of the left middle temporal gyrus (n = 27) compared to ε4(-) (n = 102). These results remained significant after multiple comparisons (pFDR < 0.05). Lastly, no statistically significant differences in FC between groups were observed for the left insular seed (pFDR > 0.05). Discussion: These results suggest early structural and functional brain changes associated with the APOE ε4 genotype on young adults. Yet, they must be cautiously interpreted and contrasted with both older adults with genetic risk for AD and patients diagnosed with AD.

Air pollution: a latent key driving force of dementia

Many researchers have studied the role of air pollutants on cognitive function, changes in brain structure, and occurrence of dementia. Due to the wide range of studies and often contradictory results, the present systematic review was conducted to try and clarify the relationship between air pollutants and dementia. To identify studies for this review, a systematic search was conducted in Scopus, PubMed, and Web of Science databases (without historical restrictions) until May 22, 2023. The PECO statement was created to clarify the research question, and articles that did not meet the criteria of this statement were excluded. In this review, animal studies, laboratory studies, books, review articles, conference papers and letters to the editors were avoided. Also, studies focused on the effect of air pollutants on cellular and biochemical changes (without investigating dementia) were also excluded. A quality assessment was done according to the type of design of each article, using the checklist developed by the Joanna Briggs Institute (JBI). Finally, selected studies were reviewed and discussed in terms of Alzheimer's dementia and non-Alzheimer's dementia. We identified 14,924 articles through a systematic search in databases, and after comprehensive reviews, 53 articles were found to be eligible for inclusion in the current systematic review. The results showed that chronic exposure to higher levels of air pollutants was associated with adverse effects on cognitive abilities and the presence of dementia. Studies strongly supported the negative effects of PM2.5 and then NO2 on the brain and the development of neurodegenerative disorders in old age. Because the onset of brain structural changes due to dementia begins decades before the onset of disease symptoms, and that exposure to air pollution is considered a modifiable risk factor, taking preventive measures to reduce air pollution and introducing behavioral interventions to reduce people's exposure to pollutants is advisable.

Free-water: A promising structural biomarker for cognitive decline in aging and mild cognitive impairment

Diffusion MRI derived free-water (FW) metrics show promise in predicting cognitive impairment and decline in aging and Alzheimer's disease (AD). FW is sensitive to subtle changes in brain microstructure, so it is possible these measures may be more sensitive than traditional structural neuroimaging biomarkers. In this study, we examined the associations among FW metrics (measured in the hippocampus and two AD signature meta-ROIs) with cognitive performance, and compared FW findings to those from more traditional neuroimaging biomarkers of AD. We leveraged data from a longitudinal cohort (nparticipants = 296, nobservations = 870, age at baseline: 73 ± 7 years, 40% mild cognitive impairment [MCI]) of older adults who underwent serial neuropsychological assessment (episodic memory, information processing speed, executive function, language, and visuospatial skills) and brain MRI over a maximum of four time points, including baseline (n = 284), 18-month (n = 246), 3-year (n = 215), and 5-year (n = 125) visits. The mean follow-up period was 2.8 ± 1.3 years. Structural MRI was used to quantify hippocampal volume, in addition to Schwarz and McEvoy AD Signatures. FW and FW-corrected fractional anisotropy (FAFWcorr) were quantified in the hippocampus (hippocampal FW) and the AD signature areas (SchwarzFW, McEvoyFW) from diffusion-weighted (dMRI) images using bi-tensor modeling (FW elimination and mapping method). Linear regression assessed the association of each biomarker with baseline cognitive performance. Additionally, linear mixed-effects regression assessed the association between baseline biomarker values and longitudinal cognitive performance. A subsequent competitive model analysis was conducted on both baseline and longitudinal data to determine how much additional variance in cognitive performance was explained by each biomarker compared to the covariate only model, which included age, sex, race/ethnicity, apolipoprotein-ε4 status, cognitive status, and modified Framingham Stroke Risk Profile scores. All analyses were corrected for multiple comparisons using an FDR procedure. Cross-sectional results indicate that hippocampal volume, hippocampal FW, Schwarz and McEvoy AD Signatures, and the SchwarzFW and McEvoyFW metrics are all significantly associated with memory performance. Baseline competitive model analyses showed that the McEvoy AD Signature and SchwarzFW explain the most unique variance beyond covariates for memory (ΔRadj 2 = 3.47 ± 1.65%) and executive function (ΔRadj 2 = 2.43 ± 1.63%), respectively. Longitudinal models revealed that hippocampal FW explained substantial unique variance for memory performance (ΔRadj 2 = 8.13 ± 1.25%), and outperformed all other biomarkers examined in predicting memory decline (pFDR = 1.95 x 10-11). This study shows that hippocampal FW is a sensitive biomarker for cognitive impairment and decline, and provides strong evidence for further exploration of this measure in aging and AD.

Neurometabolic topography and associations with cognition in Alzheimer's disease: A whole-brain high-resolution 3D MRSI study

INTRODUCTION

Altered neurometabolism, detectable via proton magnetic resonance spectroscopic imaging (1H-MRSI), is spatially heterogeneous and underpins cognitive impairments in Alzheimer's disease (AD). However, the spatial relationships between neurometabolic topography and cognitive impairment in AD remain unexplored due to technical limitations.

METHODS

We used a novel whole-brain high-resolution 1H-MRSI technique, with simultaneously acquired 18F-florbetapir positron emission tomography (PET) imaging, to investigate the relationship between neurometabolic topography and cognitive functions in 117 participants, including 22 prodromal AD, 51 AD dementia, and 44 controls.

RESULTS

Prodromal AD and AD dementia patients exhibited spatially distinct reductions in N-acetylaspartate, and increases in myo-inositol. Reduced N-acetylaspartate and increased myo-inositol were associated with worse global cognitive performance, and N-acetylaspartate correlated with five specific cognitive scores. Neurometabolic topography provides biological insights into diverse cognitive dysfunctions.

DISCUSSION

Whole-brain high-resolution 1H-MRSI revealed spatially distinct neurometabolic topographies associated with cognitive decline in AD, suggesting potential for noninvasive brain metabolic imaging to track AD progression.

HIGHLIGHTS

Whole-brain high-resolution 1H-MRSI unveils neurometabolic topography in AD. Spatially distinct reductions in NAA, and increases in mI, are demonstrated. NAA and mI topography correlates with global cognitive performance. NAA topography correlates with specific cognitive performance.

Recent advances in Alzheimer's disease: Mechanisms, clinical trials and new drug development strategies

Alzheimer's disease (AD) stands as the predominant form of dementia, presenting significant and escalating global challenges. Its etiology is intricate and diverse, stemming from a combination of factors such as aging, genetics, and environment. Our current understanding of AD pathologies involves various hypotheses, such as the cholinergic, amyloid, tau protein, inflammatory, oxidative stress, metal ion, glutamate excitotoxicity, microbiota-gut-brain axis, and abnormal autophagy. Nonetheless, unraveling the interplay among these pathological aspects and pinpointing the primary initiators of AD require further elucidation and validation. In the past decades, most clinical drugs have been discontinued due to limited effectiveness or adverse effects. Presently, available drugs primarily offer symptomatic relief and often accompanied by undesirable side effects. However, recent approvals of aducanumab (1) and lecanemab (2) by the Food and Drug Administration (FDA) present the potential in disrease-modifying effects. Nevertheless, the long-term efficacy and safety of these drugs need further validation. Consequently, the quest for safer and more effective AD drugs persists as a formidable and pressing task. This review discusses the current understanding of AD pathogenesis, advances in diagnostic biomarkers, the latest updates of clinical trials, and emerging technologies for AD drug development. We highlight recent progress in the discovery of selective inhibitors, dual-target inhibitors, allosteric modulators, covalent inhibitors, proteolysis-targeting chimeras (PROTACs), and protein-protein interaction (PPI) modulators. Our goal is to provide insights into the prospective development and clinical application of novel AD drugs.

An 11-Fold Higher Risk of Incident Mild Cognitive Impairment With Hispanic Ethnicity and Baseline Neuropsychiatric Symptoms

OBJECTIVE

Neuropsychiatric symptoms (NPSs) have been linked to cognitive decline. This study explored ethnic differences and the effects of baseline NPSs on incident mild cognitive impairment (MCI) among 386 Hispanic and non-Hispanic participants from the Texas Harris Alzheimer's Research Study.

METHODS

Data on NPSs from the Neuropsychiatric Inventory Questionnaire were available for all participants. Cox proportional hazards regression models were used to estimate the effect of ≥1 NPS at baseline and Hispanic ethnicity on incident MCI over a 7-year follow-up period.

RESULTS

NPSs at baseline were associated with incident MCI for Hispanic participants but not non-Hispanic participants. Being Hispanic with at least one NPS at baseline had an 11-times higher risk of incident MCI.

CONCLUSIONS

The Hispanic participants converted to MCI to a greater extent than the non-Hispanic participants. Only depressive symptoms increased the risk of MCI among non-Hispanics. Being of Hispanic ethnicity and having NPSs appeared to jointly increase the risk of progressing to MCI. To better understand the Alzheimer's disease continuum, further studies should explore other cultural, genetic, and medical risk factors influencing disease progression. Our findings strongly suggest the need to incorporate NPSs as outcomes of disease progression in future clinical trials involving Hispanic participants.