Current Alzheimer research最新文献

Introduction: The present study has examined microglial and astrocyte activation in association with neuronal degeneration in an animal model using an injection of amyloid-beta peptide Aβ_1-42 (Aβ₄₂) plus fibrinogen into rat hippocampus.

Methods: The combination of stimuli is suggested as a novel and potent perturbation to induce gliosis and the production of glial-derived neurotoxic factors in an animal model exhibiting a leaky BBB (blood-brain barrier). Specifically, Aβ₄₂ + fibrinogen stimulation elevated levels of COX-2 (cyclooxygenase-2) and iNOS (inducible nitric oxide synthase) with a considerable extent of neuronal loss associated with microglia and astrocyte activation.

Results: Treatment of injected rats with the broad spectrum anti-inflammatory agent, minocycline or the iNOS inhibitor, 1400 W inhibited gliosis, reduced levels of COX-2 and iNOS, and demonstrated efficacy for neuroprotection.

Conclusion: The findings suggest the utility of combining amyloid beta peptide plus fibrinogen as a potent and understudied neuroinflammatory stimulus for the induction of glial-derived neurotoxic factors in BBB-compromised AD brain.

Background and objectives: Neuropsychiatric symptoms (NPS), including psychotic symptoms (hallucinations, illusions, delusions), agitation/aggression, and depressed mood, are common in individuals with Alzheimer's disease (AD) and predict poorer outcomes, including faster disease progression. We aimed to evaluate associations between NPS and cognition and dependence in a multi-ethnic sample of community-dwelling older adults with AD.

Methods: Predictors 3 (P3) is a cohort study of AD disease courses recruiting older adults aged 65 and above residing in upper Manhattan. A total of 138 of 293 participants had probable AD at the study baseline. We fit linear mixed models to examine longitudinal associations of time-varying NPS (psychotic symptoms, agitation/aggression, and depressed mood) with dependence and cognition, adjusted for race-ethnicity, sex, education, age, clinical dementia rating score, APOE-ε4, and comorbidity burden; separate interaction models were fit for age, Hispanic ethnicity, and sex.

Results: Psychotic symptoms were associated with faster rates of increasing dependence and declining cognition over time, agitation/aggression with faster rates of declining cognition, and depressed mood with faster rates of increasing dependence. Among psychotic symptoms, delusions, but not hallucinations or illusions, were associated with worse outcome trajectories. Depressed mood predicted an accelerated increase in dependence in males but not females.

Conclusion: Our results confirm and extend prior results in clinic-based samples. The presence of NPS was associated with worse trajectories of dependence and cognition in this muti-ethnic sample of older adults with AD. Importantly, sex modified the association between depressed mood and dependence. Our results on NPS as predictors of differential AD progression in a community-dwelling, ethnically diverse sample serve to better inform the clinical care of patients and the future development of AD therapies.

The lack of effective treatments for cognitive decline in older adults has led to an interest in the possibility that lifestyle interventions can help to prevent changes in mental functioning and reduce the risk for dementia. Multiple lifestyle factors have been related to risk for decline, and multicomponent intervention studies suggest that changing older adults' behaviors can have a positive impact on their cognition. How to translate these findings into a practical model for clinical use with older adults, however, is not clear. In this Commentary, we propose a shared decision-making model to support clinicians' efforts to promote brain health in older persons. The model organizes risk and protective factors into three broad groups based on their mechanism of action and provides older persons with basic information to allow them to make evidence- and preference-based choices in choosing goals for effective brain health programs. A final component includes basic instruction in behavior change strategies such as goal setting, self-monitoring, and problem-solving. The implementation of the model will support older persons' efforts to develop a personally relevant and effective brainhealthy lifestyle that may help to reduce their risk for cognitive decline.

Background: Self-imagination refers to a mnemonic strategy of imagining oneself at a scene related to a cue.

Objective: We tested the effect of self-imagination on memory recall in Alzheimer's disease (AD) Methods: Individuals with AD and healthy controls were invited to perform two conditions. In the control (i.e., semantic elaboration) condition, participants were asked to define to which semantic category (e.g., dance) words (e.g., waltz) belong. However, in a self-imagining condition, participants were asked to imagine themselves in a scene related to the stimuli (e.g., dancing waltz). Both conditions were followed by two free memory tests with two different intervals (20 seconds vs. 20 minutes).

Results: Analysis showed a beneficial effect of self-imagination for the 20-second but not for the 20- minute recall in AD participants and controls.

Conclusion: Clinicians can incorporate our findings when assessing, especially when trying to rehabilitate, episodic memory in AD.

Background: Alzheimer's disease (AD) and behavioral variant frontotemporal dementia (bvFTD) are important causes of dementia with challenging differential diagnoses in many cases. Addenbrooke's Cognitive Examination-Revised (ACE-R) is a cognitive battery that may be useful to differentiate the two disorders.

Objective: The objectibe of this study is to investigate the value of the ACE-R combined with sociodemographic factors in the differential diagnosis between AD and bvFTD.

Methods: The ACE-R was administered to 102 patients with mild dementia due to probable AD, 37 with mild bvFTD, and 135 controls. Performances of patients and controls were analyzed by logistic regression and by ROC curves to refine the diagnostic accuracy of the ACE-R in AD and bvFTD.

Results: The ACE-R subscores Attention and Orientation, Fluency, and Memory, in combination with schooling differentiated AD from controls with an area under the ROC curve (AUC) of 0.936 (86% sensitivity and 87% specificity). The ACE-R subscores Attention and Orientation, Fluency, and Language, in combination with sex (male), age, and schooling, discriminated bvFTD from controls with an AUC of 0.908 (81% sensitivity and 95% specificity). In the differentiation between AD and bvFTD, the ACE-R subscores Attention and Orientation, Fluency, and Language, together with age, displayed an AUC of 0.865 (78% sensitivity and 85% specificity).

Conclusion: The combination of ACE-R scores with sociodemographic data allowed good differentiation between AD and bvFTD in the study sample.

Amyloid plaques and neurofibrillary tangles are two main characteristics of Alzheimer's disease (AD). As cerebral resident phagocytes, microglia have different roles in Aβ pathology and tau pathology. In this review, we discuss microglial functions in the formation, clearance, and spread of Aβ and tau. Many receptors and enzymes, which are related to microglia, participate in AD pathologies and thus are thought to be potential targets of AD. So, making use of microglia can be beneficial to confine AD pathologies. To sum up, this article review the roles of microglia in AD pathology and possible corresponding treatments.

Background: Alzheimer's disease (AD) and Multiple sclerosis (MS) lead to neurodegenerative processes negatively affecting millions of people worldwide. Their treatment is still difficult and practically incomplete. One of the most commonly used drugs against these neurodegenerative diseases is 4-aminopyridine. However, its use is confined by the high toxicity.

Objectives: The aim of this work is to obtain new peptide derivatives of 4-aminopyridine with decreased toxicity compared to 4-aminopyridine.

Methods: Synthesis was conducted in solution using a consecutive condensation approach. The new derivatives were characterized by melting points, NMR, and Mass spectra. Important ADME (absorption, distribution, metabolism, and excretion) properties have been studied in silico using ACD/Percepta v.2020.2.0 software. Acute toxicity was determined in mice according to a Standard protocol. All new derivatives were tested in vitro for cytotoxic activity in a panel of human (HEP-G2, BV-173) and murine (NEURO 2A) tumor cell lines via a standard MTT-based colorimetric method. β-secretase inhibitory activity was determined by applying the fluorescent method.

Results: New derivatives of 4-aminopyridine containing analogues of the β-secretase inhibitory peptide (Boc-Val-Asn-Leu-Ala-OH) were obtained. The in vivo toxicity of the tested compounds was found to be as high as 1500 mg/kg. Cell toxicity screening against tumor cell lines of different origins showed negligible growth-inhibitory effects of all investigated 4-aminopyridine analogues.

Conclusion: Synthesis of new peptide derivatives of 4-aminopyridine is reported. Acute toxicity studies revealed a ca. 150 times lower toxicity of the new compounds as compared to 4-aminopyridine that may be ascribed to their peptide fragment.

Beyond the time-honoured targeting of protein misfolding and aggregation, Alzheimer's disease needs new, innovative therapeutic directions. When exploring alternative druggable mechanisms, multifaceted in vitro and in vivo data demonstrate that immune system dysfunction is a pivotal driver of Alzheimer's disease progression. In pursuing neuroimmunological targets, a major but often under-discussed consideration regards the issue of whether innate or adaptive immunity (or both) within the neuroimmune network should be the centre of focus when devising immunotherapeutic approaches to Alzheimer's. This perspective article briefly reviews current data, concluding that while both innate and adaptive immunity contributes to the immunopathology of Alzheimer's, the proinflammatory microglia and cytokines of innate immunity will provide higher yield targets with a greater likelihood of efficacy. Although it seems paradoxical to focus on a rapid, short-lived aspect of immunity when seeking approaches to a quintessentially chronic brain disease, accumulating evidence affords ample data to support the target-rich cascade of innate immunity for the development of much-needed new diagnostics and therapeutics.