Journal of Alzheimer's Disease最新文献

Background: Recent research suggests that selective serotonin reuptake inhibitors (SSRIs) may reduce mortality in COVID-19 patients; however, research into their benefits for elderly Alzheimer's disease (AD) patients remains limited.

Objective: To investigate the relationship between SSRIs therapy and the mortality risk after COVID-19 infection in elderly patients with and without AD.

Methods: This retrospective cohort study leveraged a large database containing over 100 million electronic health records in the US from the TriNetX platform to compare the hazard rates of mortality after COVID-19 infection in elderly AD patients prescribed SSRIs versus propensity-score matched individuals prescribed other antidepressants. This study was also conducted in separate cohorts of patients without AD to compare the findings.

Results: When compared with non-SSRI antidepressants, SSRIs were associated with lower risk for mortality after COVID-19 infection in elderly patients without AD over early, middle, and later stages of the pandemic with HRs of 0.84 (95% CI: 0.75-0.93), 0.86 (95% CI: 0.79-0.93), and 0.77 (95% CI: 0.71-0.33), respectively. When comparing SSRIs with non-SSRI antidepressants for mortality risk following COVID-19 among patients with AD, HRs of 0.95 (95% CI: 0.71-1.27), 0.80 (95% CI: 0.61-1.06), and 0.99 (95% CI: 0.75-1.32), were found respectively.

Conclusions: Our findings suggest that the use of SSRIs is significantly associated with reduced mortality risk following COVID-19 in elderly patients without AD compared to other antidepressants. While a lower mortality risk was also observed among AD patients, the association was not statistically significant.

Background: A deep knowledge of the healthcare system and the organization of neurology departments is important for planning and optimizing changes to facilitate the successful implementation of anti-amyloid antibodies treatments.

Objective: We aimed to assess the necessary changes prior to introducing these therapies in our setting.

Methods: We conducted a key informant survey among heads of departments of neurology from 16 hospitals in Spain. The questionnaire comprised questions about changes in the organization and functioning of the departments of neurology with the introduction of anti-amyloid drugs, changes in diagnosis and patient care, use of diagnostic techniques, patients, families and public information, resources allocation, and research.

Results: Sixteen key informants completed the survey. They strongly agreed that the introduction of anti-amyloid drugs will impact the functioning of neurology services, especially in hospitals with dementia units. Consensus was reached regarding referring all Alzheimer's disease patients eligible for therapy to dementia units. There was also agreement on the need to expand the neurology services, day hospital units, extend visit durations, and hire more professionals, especially neurologists, neuropsychologists, and nuclear medicine physicians. Furthermore, consensus was achieved on increasing the use of MRI, amyloid PET, cerebrospinal fluid biomarkers, APOE genotyping, and the necessity of advancing blood biomarkers and tau tracers.

Conclusions: Our study highlights the need for extensive changes within Spanish neurological departments to effectively integrate anti-amyloid antibodies. Implementing these changes is essential for the timely and equitable adoption of novel therapies.

Background: The impact of social isolation on social cognition is not entirely clear.

Objective: The aim of the study is to investigate the association between social isolation and social cognition.

Methods: In a population-based sample of 83 individuals aged 50+ years without dementia, we assessed the relationship between social isolation (measured by the Lubben Social Network Scale - LSNS-6) and performance on emotional recognition (measured by the Emotion Recognition Task (ERT)) and on Theory of Mind (ToM) abilities (measured by the Reading the Mind in the Eyes Test (RMET)), two core aspects of social cognition.

Results: No significant association was found between social isolation and ToM abilities for both the unadjusted and adjusted models. Similarly, no significant association was observed between social isolation and emotion recognition.

Conclusions: Further research is needed to understand the complex correlation between social relationships and cognitive health, particularly in different cognitive domains, adopting a life course perspective.

Background: The efficacy and safety of 40 Hz gamma transcranial alternating current stimulation (γ-tACS) in Alzheimer's disease (AD) are still uncertain.

Objective: This meta-analysis was conducted to investigate the therapeutic potential and safety of 40 Hz γ-tACS for AD.

Methods: The meta-analysis was conducted by systematically searching four databases from their start to 28 December 2023. Subgroup analyses were performed to identify the intervention effects of γ-tACS.

Results: Of the 7 included studies, γ-tACS has a notable impact on improving overall cognition [standardized mean difference (SMD): 0.49, 95% CI: 0.09 to 0.89], memory (SMD: 0.79, 95% CI: 0.18 to 1.41), and cholinergic transmission (weighted mean difference: -0.40, 95% CI: -0.43 to -0.37). Furthermore, subgroup analysis revealed that γ-tACS treatment had a substantial impact on enhancing memory targeting the left angular gyrus in both home (SMD: 3.12, 95% CI: 1.54 to 4.70) and non-home settings (SMD: 0.53, 95% CI: 0.24 to 0.82). However, γ-tACS had a positive effect on overall cognition in non-home settings (SMD: 0.55, 95% CI 0.11 to 0.98), but not in home settings (SMD: 0.22, 95% CI -0.76 to 1.20). Additionally, targeting temporo-frontal or bitemporal γ-tACS treatment resulted in improvement in overall cognition (SMD: 0.61, 95% CI: 0.06 to 1.16), but not targeting the left angular gyrus (SMD: 0.22, 95% CI: -0.76 to 1.20).

Conclusions: γ-tACS could be beneficial in enhancing cognition, memory and restoring cholinergic dysfunction in AD. The different selection of stimulation sites plays distinct roles. Meanwhile, AD patients are recommended to receive γ-tACS treatment at home.

Background: Klotho, encoded by the KLOTHO gene, is an anti-aging and neuroprotective protein. KLOTHO KL-VS heterozygosity (KL-VS_HET) is hypothesized to be protective against the accumulation of Alzheimer's disease (AD) neuropathological hallmarks (amyloid-β (Aβ) and tau).

Objective: We examine whether being positive for Aβ (A+) or tau (T+), or A/T joint status [positive for Aβ (A + T-), tau (A-T+), both (A + T+) or neither (A-T-)] vary by KL-VS and whether serum klotho protein levels vary based on A+, T+, or A/T status in a cohort enriched for AD risk.

Methods: The sample consisted of 704 cognitively unimpaired, late middle-aged, and older adults; Mean_Age(SD) = 64.9(8.3). Serum klotho was available for a sub-sample of 396 participants; Mean_Age(SD) = 66.8(7.4). Covariate-adjusted logistic regression examined whether A + or T+, and multinomial regression examined whether A/T status, vary by KL-VS genotype. Covariate-adjusted linear regression examined whether serum klotho levels differ based on A+, T+, or A/T status.

Results: A+ prevalence was lower in KL-VS_HET (p = 0.05), with no differences in T + prevalence (p = 0.52). KL-VS_HET also had marginally lower odds of being A + T- (p = 0.07). Serum klotho levels did not differ based on A+, T+, or A/T status (all ps ≥ 0.40).

Conclusions: KL-VS_HET is associated with lower odds of being positive for Aβ, regardless of whether one is also positive for tau. Conversely, the likelihood of being tau positive did not differ based on KL-VS genotype. Our findings add to the growing KLOTHO literature and suggests the need for further research focused on understanding the mechanisms underlying KL-VS-related putative resilience to AD.

Background: Clinical diagnosis in primary progressive aphasia (PPA) is challenging. Recently, emphasis has been placed on the importance of screening evaluation. Three different screening tests that use different strategies based on the assessment of language (Mini-Linguistic State Examination, MLSE) or different cognitive domains (Addenbrooke's Cognitive Examination, ACE-III and Dépistage Cognitif de Québec, DCQ) have been proposed and independently validated. These tests aim to detect PPA and classify into the three main variants (non-fluent (nfvPPA), semantic (svPPA) and logopenic (lvPPA)).

Objective: This study aims to evaluate and compare the diagnostic capacity of these three instruments in PPA.

Methods: A cross-sectional study including 43 patients with PPA (nfvPPA (n = 19), svPPA (n = 8), and lvPPA (n = 16)) and 21 cognitively unimpaired controls was conducted. Clinical diagnoses were established based on an extensive multidisciplinary assessment including neuropsychological assessment, fluorodeoxyglucose-positron emission tomography, MRI, and cerebrospinal fluid biomarkers. Both PPA patients and controls completed the three tests (MLSE, ACE-III, and DCQ).

Results: Internal consistency was excellent for the three tests. The area under the curve for the diagnosis of PPA was 0.950 for MLSE, 0.953 for ACE-III, and 0.933 for DCQ. Correlations between the three tests were high. The MLSE, ACE-III, and DCQ tests obtained adequate levels of discrimination between the variants of PPA, with accuracies between 76-79%.

Conclusions: This study confirms the validity of ACE-III, MLSE, and DCQ for the diagnosis of PPA and its variants. This suggests that detailed assessment of linguistic characteristics (MLSE) and non-linguistic features (DCQ, ACE-III) are relevant for the diagnosis and classification of PPA.

Background: Blood metabolites have emerged as promising candidates in the search for biomarkers for Alzheimer's disease (AD), as evidence shows that various metabolic derangements contribute to neurodegeneration in AD.

Objective: We aim to identify metabolic biomarkers for AD diagnosis.

Methods: We conducted an in-depth analysis of the serum metabolome of AD patients and age, sex-matched cognitively unimpaired older adults using ultra-high-performance liquid chromatography-high resolution mass spectrometry. The biomarkers associated with AD were identified using machine learning algorithms.

Results: Using the discovery dataset and support vector machine (SVM) algorithm, we identified a panel of 14 metabolites predicting AD with a 1.00 area under the curve (AUC) of receiver operating characteristic (ROC). The SVM model was tested against the verification dataset using an independent cohort and retained high predictive accuracy with a 0.97 AUC. Using the random forest (RF) algorithm, we identified a panel of 13 metabolites that predicted AD with a 0.96 AUC when tested against the verification dataset.

Conclusions: These findings pave the way for an efficient, blood-based diagnostic test for AD, holding promise for clinical screenings and diagnostic procedures.

Background: Clinical and preclinical studies have shown that extra virgin olive oil (EVOO), a major component of the Mediterranean diet, has beneficial effects on brain aging and cognition. Individuals with Down syndrome develop age-dependent cognitive decline and synaptic dysfunction. However, whether EVOO intake is beneficial in Down syndrome is not known.

Objective: In this study, by implementing a mouse model of Down syndrome, we aimed to investigate the effect that chronic administration of EVOO has on memory, synaptic function, and neuroinflammation.

Methods: Starting at 4 months of age Ts65dn mice were randomized to receive EVOO for 5 months in their diet, after which they were tested for learning and memory impairment. After euthanasia, synaptic function was measured in freshly obtained hippocampal slices, whereas brain tissues were assessed for inflammatory biomarkers.

Results: Compared with controls, mice receiving EVOO had a significant improvement in learning and spatial memory. Additionally, field potential recordings showed that treated mice had an improvement in synaptic function. Finally, array analysis showed that EVOO modulated the expression levels of several inflammatory biomarkers.

Conclusions: Chronic administration of EVOO to a mouse model of Down syndrome has beneficial effects on memory impairments, synaptic function deficits and neuroinflammation. Our findings provide additional support for the potential therapeutic effects of EVOO also in individuals with Down syndrome.

Background: Genetic variations in a common single nucleotide polymorphism in the ninth intron of the KIBRA gene have been linked to memory performance and risk of Alzheimer's disease (AD).

Objective: We examined the risk of AD related to presence of KIBRA T allele (versus CC homozygote) and to memory performance. The role of established genetic risk factors APOE ε4 and BDNF Met was also considered.

Methods: Participants were cognitively healthy individuals (n = 19), participants with amnestic mild cognitive impairment (aMCI) due to AD (n = 99) and AD dementia (n = 37) from the Czech Brain Aging Study. Binary and multinomial logistic regressions compared odds of belonging to a certain diagnostic category and multivariate linear regressions assessed associations with memory.

Results: KIBRA T allele was associated with increased AD dementia risk (odds ratio [OR] = 5.98, p = 0.012) compared to KIBRA CC genotype. In APOE ε4 negative individuals, KIBRA T allele was associated with a greater risk of both aMCI due to AD (OR = 6.68, p = 0.038) and AD dementia (OR = 15.75, p = 0.009). In BDNF Met positive individuals, the KIBRA T allele was associated with a greater risk of AD dementia (OR = 10.98, p = 0.050). In AD dementia, the association between KIBRA T allele and better memory performance approached significance (β = 0.42; p = 0.062). The link between possessing the KIBRA T allele and better memory reached statistical significance only among BDNF Met carriers (β = 1.21, p = 0.027).

Conclusions: Findings suggest that KIBRA T allele may not fully protect against AD dementia but could potentially delay progression of post-diagnosis cognitive deficits.

Background: No large-scale characterizations of neurofilament light chain (NfL) and cognitive outcomes have been conducted in community-dwelling non-Hispanic Blacks.

Objective: This study aims to enhance the application of blood biomarkers, in particular NfL, to ethno-racially diverse communities. We assess the association of NfL with cognitive outcomes, hypothesizing that NfL can identify cognitive changes regardless of diagnostic category.

Methods: Baseline data were analyzed among n = 283 non-Hispanic Blacks (NHB) from the multi-ethnic Health and Aging Brain Study- Health Disparities (HABS-HD). Plasma NfL was measured on the Simoa platform. Linear regression models were conducted, covarying for age, gender, and education.

Results: The majority of study participants (72%) were cognitively unimpaired (CU), with 21% having mild cognitive impairment (MCI), and 6.7% with Alzheimer's disease (AD). In adjusted models among the entire sample, significant associations existed between NfL and Trails A (p < 0.0001), Trails B (p < 0.0001), phonemic (FAS) and semantic (Animals) fluency (p = 0.03), and Symbol Digit Substitution (p < 0.001). When separated by diagnostic classification, significant associations were removed for functions involving executive functions for all diagnostic groups. Higher levels of NfL were positively associated with cognitive diagnosis, older age, and less education.

Conclusions: Plasma NfL levels are significantly associated with measures of executive functioning, which elucidate NfL as a non-specific marker of neurodegeneration associated with efficiency of brain functions involving attention, processing, and generativity. NfL may be a sensitive measure for the detection of alterations in cognitive processing before the onset of phenotypic functional changes of neurodegeneration.