Clinical course of Alzheimer’s disease

Author(s):  
Alberto Lleo ◽  
Rafael Blesa

• Alzheimer’s disease is an age-related neurodegenerative disorder, with onset usually in late life, characterized by cognitive impairment, a variety of behavioural symptoms, and restrictions in the activities of daily living• The initial symptom is episodic memory loss, in particular in delayed recall of visual and/or verbal material. Immediate and remote memory is usually preserved in early stages...

Author(s):  
Alberto Lleó ◽  
Rafael Blesa

Alzheimer’s disease (AD) is an age-related neurodegenerative disorder, with onset usually in late life, characterized by progressive cognitive impairment, a variety of behavioural symptoms, and impairment in the activities of daily living. The initial symptom in typical AD is episodic memory loss, which reflects hippocampal dysfunction. The memory deficits are very characteristic with low recall performance despite retrieval facilitations with cueing. These initial deficits can be identified by appropriate cognitive tests. Behavioural symptoms can be present at early stages of the disease (even in pre-clinical states), although the frequency increases as the disease progresses. In the past decade there has been a growing interest in characterizing these pre-clinical and prodromal stages as treatments are expected to be more effective in these phases.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Megan K. Elder ◽  
Hediye Erdjument-Bromage ◽  
Mauricio M. Oliveira ◽  
Maggie Mamcarz ◽  
Thomas A. Neubert ◽  
...  

AbstractAlzheimer’s disease (AD) is an age-related neurodegenerative disorder associated with memory loss, but the AD-associated neuropathological changes begin years before memory impairments. Investigation of the early molecular abnormalities in AD might offer innovative opportunities to target memory impairment prior to onset. Decreased protein synthesis plays a fundamental role in AD, yet the consequences of this dysregulation for cellular function remain unknown. We hypothesize that alterations in the de novo proteome drive early metabolic alterations in the hippocampus that persist throughout AD progression. Using a combinatorial amino acid tagging approach to selectively label and enrich newly synthesized proteins, we found that the de novo proteome is disturbed in young APP/PS1 mice prior to symptom onset, affecting the synthesis of multiple components of the synaptic, lysosomal, and mitochondrial pathways. Furthermore, the synthesis of large clusters of ribosomal subunits were affected throughout development. Our data suggest that large-scale changes in protein synthesis could underlie cellular dysfunction in AD.


2020 ◽  
Vol 20 (13) ◽  
pp. 1214-1234 ◽  
Author(s):  
Md. Tanvir Kabir ◽  
Md. Sahab Uddin ◽  
Bijo Mathew ◽  
Pankoj Kumar Das ◽  
Asma Perveen ◽  
...  

Background: Alzheimer's disease (AD) is a chronic neurodegenerative disorder and the characteristics of this devastating disorder include the progressive and disabling deficits in the cognitive functions including reasoning, attention, judgment, comprehension, memory, and language. Objective: In this article, we have focused on the recent progress that has been achieved in the development of an effective AD vaccine. Summary: Currently, available treatment options of AD are limited to deliver short-term symptomatic relief only. A number of strategies targeting amyloid-beta (Aβ) have been developed in order to treat or prevent AD. In order to exert an effective immune response, an AD vaccine should contain adjuvants that can induce an effective anti-inflammatory T helper 2 (Th2) immune response. AD vaccines should also possess the immunogens which have the capacity to stimulate a protective immune response against various cytotoxic Aβ conformers. The induction of an effective vaccine’s immune response would necessitate the parallel delivery of immunogen to dendritic cells (DCs) and their priming to stimulate a Th2-polarized response. The aforesaid immune response is likely to mediate the generation of neutralizing antibodies against the neurotoxic Aβ oligomers (AβOs) and also anti-inflammatory cytokines, thus preventing the AD-related inflammation. Conclusion: Since there is an age-related decline in the immune functions, therefore vaccines are more likely to prevent AD instead of providing treatment. AD vaccines might be an effective and convenient approach to avoid the treatment-related huge expense.


Nutrients ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 3082
Author(s):  
M. Victoria Moreno-Arribas ◽  
Begoña Bartolomé ◽  
José L. Peñalvo ◽  
Patricia Pérez-Matute ◽  
Maria José Motilva

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder leading to the most common form of dementia in elderly people. Modifiable dietary and lifestyle factors could either accelerate or ameliorate the aging process and the risk of developing AD and other age-related morbidities. Emerging evidence also reports a potential link between oral and gut microbiota alterations and AD. Dietary polyphenols, in particular wine polyphenols, are a major diver of oral and gut microbiota composition and function. Consequently, wine polyphenols health effects, mediated as a function of the individual’s oral and gut microbiome are considered one of the recent greatest challenges in the field of neurodegenerative diseases as a promising strategy to prevent or slow down AD progression. This review highlights current knowledge on the link of oral and intestinal microbiome and the interaction between wine polyphenols and microbiota in the context of AD. Furthermore, the extent to which mechanisms bacteria and polyphenols and its microbial metabolites exert their action on communication pathways between the brain and the microbiota, as well as the impact of the molecular mediators to these interactions on AD patients, are described.


2020 ◽  
Vol 14 ◽  
Author(s):  
Antonio Munafò ◽  
Chiara Burgaletto ◽  
Giulia Di Benedetto ◽  
Marco Di Mauro ◽  
Rosaria Di Mauro ◽  
...  

Alzheimer’s disease (AD) is the most common age-related neurodegenerative disorder characterized by cognitive decline and by the presence of amyloid β plaques and neurofibrillary tangles in the brain. Despite recent advances in understanding its pathophysiological mechanisms, to date, there are no disease-modifying therapeutic options, to slow or halt the evolution of neurodegenerative processes in AD. Current pharmacological treatments only transiently mitigate the severity of symptoms, with modest or null overall improvement. Emerging evidence supports the concept that AD is affected by the impaired ability of the immune system to restrain the brain’s pathology. Deep understanding of the relationship between the nervous and the immune system may provide a novel arena to develop effective and safe drugs for AD treatment. Considering the crucial role of inflammatory/immune pathways in AD, here we discuss the current status of the immuno-oncological, immunomodulatory and anti-TNF-α drugs which are being used in preclinical studies or in ongoing clinical trials by means of the drug-repositioning approach.


2020 ◽  
Vol 21 (21) ◽  
pp. 8014
Author(s):  
Sudip Dhakal ◽  
Ian Macreadie

Alzheimer’s Disease (AD) is a progressive multifactorial age-related neurodegenerative disorder that causes the majority of deaths due to dementia in the elderly. Although various risk factors have been found to be associated with AD progression, the cause of the disease is still unresolved. The loss of proteostasis is one of the major causes of AD: it is evident by aggregation of misfolded proteins, lipid homeostasis disruption, accumulation of autophagic vesicles, and oxidative damage during the disease progression. Different models have been developed to study AD, one of which is a yeast model. Yeasts are simple unicellular eukaryotic cells that have provided great insights into human cell biology. Various yeast models, including unmodified and genetically modified yeasts, have been established for studying AD and have provided significant amount of information on AD pathology and potential interventions. The conservation of various human biological processes, including signal transduction, energy metabolism, protein homeostasis, stress responses, oxidative phosphorylation, vesicle trafficking, apoptosis, endocytosis, and ageing, renders yeast a fascinating, powerful model for AD. In addition, the easy manipulation of the yeast genome and availability of methods to evaluate yeast cells rapidly in high throughput technological platforms strengthen the rationale of using yeast as a model. This review focuses on the description of the proteostasis network in yeast and its comparison with the human proteostasis network. It further elaborates on the AD-associated proteostasis failure and applications of the yeast proteostasis network to understand AD pathology and its potential to guide interventions against AD.


1994 ◽  
Vol 6 (1) ◽  
pp. 23-44 ◽  
Author(s):  
Gary W. Small ◽  
Anna Okonek ◽  
Mark A. Mandelkern ◽  
Asenath La Rue ◽  
Linda Chang ◽  
...  

To determine the relationships between clinical and brain function in persons with a familial risk for Alzheimer's disease, the authors assessed subjective and objective cognitive abilities, mood state, and cerebral glucose metabolism (using positron emission tomography) in 43 persons with age-associated memory impairment, with and without first-degree relatives with a clinical diagnosis of Alzheimer's disease. Subjective complaints of memory loss, mood state ratings, and objective memory measures were similar in persons with a family history of Alzheimer's disease (n = 29) compared to those without such a history (n = 14). Metabolic ratios in the frontal regions correlated with a decrease in a specific type of subjective memory complaint (mnemonics usage; p < .001) and some mood state ratings. These results indicate that parietal and temporal hypometabolism is not evident in persons with mild age-related memory complaints, even when such subjects have a familial risk for Alzheimer's disease. Moreover, self-reports of mnemonics usage may be sensitive indicators of decreased frontal lobe function. Longitudinal study will determine whether such clinical and metabolic measures will predict eventual disease progression.


2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Troy T. Rohn

Alzheimer's disease (AD) is an age-related neurodegenerative disorder characterized by a progressive loss of memory and cognitive skills. Although much attention has been devoted concerning the contribution of the microscopic lesions, senile plaques, and neurofibrillary tangles to the disease process, inflammation has long been suspected to play a major role in the etiology of AD. Recently, a novel variant in the gene encoding the triggering receptor expressed on myeloid cells 2 (TREM2) has been identified that has refocused the spotlight back onto inflammation as a major contributing factor in AD. Variants in TREM2 triple one's risk of developing late-onset AD. TREM2 is expressed on microglial cells, the resident macrophages in the CNS, and functions to stimulate phagocytosis on one hand and to suppress cytokine production and inflammation on the other hand. The purpose of this paper is to discuss these recent developments including the potential role that TREM2 normally plays and how loss of function may contribute to AD pathogenesis by enhancing oxidative stress and inflammation within the CNS. In this context, an overview of the pathways linking beta-amyloid, neurofibrillary tangles (NFTs), oxidative stress, and inflammation will be discussed.


2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Fanhui Meng ◽  
Jun Li ◽  
Yanqiu Rao ◽  
Wenjun Wang ◽  
Yan Fu

Alzheimer’s disease (AD) is an age-related neurodegenerative disorder, and the few drugs that are currently available only treat the symptoms. Traditional medicine or phytotherapy has been shown to protect against AD. In our previous studies, Gengnianchun (GNC), a traditional Chinese medicine formula with a prolongevity effect, protected against Aβ-induced cytotoxicity in pheochromocytoma cells (PC-12 cells) and hippocampal cells. Here, we investigated the effects and possible mechanisms by which GNC protected against Aβtoxicity using transgenicCaenorhabditis elegansCL4176. Our results showed that GNC effectively delayed the Aβtoxicity-triggered body paralysis of CL4176 worms. GNC decreased Aβby reducing AβmRNA levels. Moreover, GNC significantly reduced reactive oxygen species in the AD model worms compared with the controls. In addition, GNC upregulated the daf-16, sod-3, hsp-16.2 genes, and enhanced DAF-16 translocation from the cytoplasm to the nuclei under oxidative stress conditions. GNC treatment ofC. elegansstrains lacking DAF-16 did not affect the paralysis phenotype. Taken together, these findings suggest that GNC could protect against Aβ-induced toxicity via the DAF-16 pathway inC. elegans. Further studies are required to analyze its effectiveness in more complex animals.


2018 ◽  
Author(s):  
Stephen A. Semick ◽  
Rahul A. Bharadwaj ◽  
Leonardo Collado-Torres ◽  
Ran Tao ◽  
Joo Heon Shin ◽  
...  

AbstractBackgroundLate-onset Alzheimer’s disease (AD) is a complex age-related neurodegenerative disorder that likely involves epigenetic factors. To better understand the epigenetic state associated with AD represented as variation in DNA methylation (DNAm), we surveyed 420,852 DNAm sites from neurotypical controls (N=49) and late-onset AD patients (N=24) across four brain regions (hippocampus, entorhinal cortex, dorsolateral prefrontal cortex and cerebellum).ResultsWe identified 858 sites with robust differential methylation, collectively annotated to 772 possible genes (FDR<5%, within 10kb). These sites were overrepresented in AD genetic risk loci (p=0.00655), and nearby genes were enriched for processes related to cell-adhesion, immunity, and calcium homeostasis (FDR<5%). We analyzed corresponding RNA-seq data to prioritize 130 genes within 10kb of the differentially methylated sites, which were differentially expressed and had expression levels associated with nearby DNAm levels (p<0.05). This validated gene set includes previously reported (e.g. ANK1, DUSP22) and novel genes involved in Alzheimer’s disease, such as ANKRD30B.ConclusionsThese results highlight DNAm changes in Alzheimer’s disease that have gene expression correlates, implicating DNAm as an epigenetic mechanism underlying pathological molecular changes associated with AD. Furthermore, our framework illustrates the value of integrating epigenetic and transcriptomic data for understanding complex disease.


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