Project description:BACKGROUND: Autosomal dominant early onset Alzheimer's disease (ADEOAD) is genetically heterogeneous. Mutations of the amyloid precursor protein (APP), presenilin 1 (PSEN1), and presenilin 2 (PSEN2) genes have been identified. OBJECTIVE: To further clarify the respective contribution of these genes to ADEOAD. METHODS: 31 novel families were investigated. They were ascertained using stringent criteria (the occurrence of probable or definite cases of Alzheimer's disease with onset before 60 years of age in three generations). All cases fulfilled the NINCDS-ADRDA criteria for probable or definite Alzheimer's disease. The entire coding regions of PSEN1 and PSEN2 genes and exons 16 and 17 of APP gene were sequenced from genomic DNA RESULTS: PSEN1 mutations, including eight previously unreported mutations, were detected in 24 of the 31 families, and APP mutations were found in five families. In this sample, the mean ages of disease onset in PSEN1 and APP mutation carriers were 41.7 and 51.2 years, respectively. CONCLUSIONS: Combining these data with previously published data, yielding 65 ADEOAD families, 66% of the cases were attributable to PSEN1 mutations and 16% to APP mutations, while 18% remained unexplained.
Project description:Alzheimer's disease is the most common cause of dementia worldwide, with the prevalence continuing to grow in part because of the aging world population. This neurodegenerative disease process is characterized classically by two hallmark pathologies: β-amyloid plaque deposition and neurofibrillary tangles of hyperphosphorylated tau. Diagnosis is based upon clinical presentation fulfilling several criteria as well as fluid and imaging biomarkers. Treatment is currently targeted toward symptomatic therapy, although trials are underway that aim to reduce the production and overall burden of pathology within the brain. Here, we discuss recent advances in our understanding of the clinical evaluation and treatment of Alzheimer's disease, with updates regarding clinical trials still in progress.
Project description:With the aging of the population, the incidence and prevalence of Alzheimer's disease will grow, increasing the burden on individuals and society. While ameliorating symptoms, the currently available treatments approved by the US Food and Drug Administration do not halt progression or cure the illness. This article discusses recent data on treatment strategies targeting amyloid and tau pathology. Novel therapeutic strategies such as inhibitors of receptors for advanced glycation end products (RAGE), potential mitochondrial modification with Dimebon, anti-inflammatory approaches, and cholesterol-lowering agents are also reviewed. An update on results from pharmacologic and nonpharmacologic prevention trials is provided.
Project description:Memory, cognition, dementia, and neurodegeneration are complexly interlinked processes with various mechanistic pathways, leading to a range of clinical outcomes. They are strongly associated with pathological conditions like Alzheimer's disease, Parkinson's disease, schizophrenia, and stroke and are a growing concern for their timely diagnosis and management. Several cognitionenhancing interventions for management include non-pharmacological interventions like diet, exercise, and physical activity, while pharmacological interventions include medicinal agents, herbal agents, and nutritional supplements. This review critically analyzed and discussed the currently available agents under different drug development phases designed to target the molecular targets, including cholinergic receptor, glutamatergic system, GABAergic targets, glycine site, serotonergic targets, histamine receptors, etc. Understanding memory formation and pathways involved therein aids in opening the new gateways to treating cognitive disorders. However, clinical studies suggest that there is still a dearth of knowledge about the pathological mechanism involved in neurological conditions, making the dropouts of agents from the initial phases of the clinical trial. Hence, a better understanding of the disease biology, mode of drug action, and interlinked mechanistic pathways at a molecular level is required.
Project description:Alzheimer's Disease (AD) and Non-Demented Control (NDC) human sera were probed onto human protein microarrays in order to identify differentially expressed autoantibody biomarkers that could be used as diagnostic indicators. In the study presented here, 50 AD and 40 NDC human serum samples were probed onto human protein microarrays in order to identify differentially expressed autoantibodies. Microarray data was analyzed using several statistical significance algorithms, and autoantibodies that demonstrated significant group prevelance were selected as biomarkers of disease. Prediction classification analysis tested the diagnostic efficacy of the identified biomarkers; and differentiation of AD samples from other neurodegeneratively-diseased and non-neurodegeneratively-diseased controls (Parkinson's disease and breast cancer, respectively) confirmed their specificity.
Project description:Genetic variations in individuals may cause differences in the response to cholinesterase inhibitor drugs used in the treatment of Alzheimer's disease (AD). Through this review, we aimed to understand the potential relationship between genetic polymorphisms and treatment response in AD. We conducted a systematic review of the studies published from 2006 to 2018 that assessed the relationship between genetic polymorphisms and the pharmacotherapeutic outcomes of patients with AD. Via several possible mechanisms, genetic polymorphisms of many genes, including ABCA1, ApoE3, CYP2D6, CHAT, CHRNA7, and ESR1, appear to have strong correlations with the treatment response of patients with AD. Indeed, these genetic polymorphisms, either in the form of single nucleotide polymorphisms or direct changes to one or more amino acids, have been shown to cause differences in the therapeutic response. In summary, our findings indicate that genetic polymorphisms should be considered in the management of AD to achieve both effective and efficient treatment outcomes in terms of cost and prognosis.
Project description:Alzheimer's Disease (AD) and Non-Demented Control (NDC) human sera were probed onto human protein microarrays in order to identify differentially expressed autoantibody biomarkers that could be used as diagnostic indicators.
Project description:Protein aggregation is common to dozens of diseases including prionoses, diabetes, Parkinson's and Alzheimer's. Over the past 15 years, there has been a paradigm shift in understanding the structural basis for these proteinopathies. Precedent for this shift has come from investigation of soluble A? oligomers (A?Os), toxins now widely regarded as instigating neuron damage leading to Alzheimer's dementia. Toxic A?Os accumulate in AD brain and constitute long-lived alternatives to the disease-defining A? fibrils deposited in amyloid plaques. Key experiments using fibril-free A?O solutions demonstrated that while A? is essential for memory loss, the fibrillar A? in amyloid deposits is not the agent. The AD-like cellular pathologies induced by A?Os suggest their impact provides a unifying mechanism for AD pathogenesis, explaining why early stage disease is specific for memory and accounting for major facets of AD neuropathology. Alternative ideas for triggering mechanisms are being actively investigated. Some research favors insertion of A?Os into membrane, while other evidence supports ligand-like accumulation at particular synapses. Over a dozen candidate toxin receptors have been proposed. A?O binding triggers a redistribution of critical synaptic proteins and induces hyperactivity in metabotropic and ionotropic glutamate receptors. This leads to Ca(2+) overload and instigates major facets of AD neuropathology, including tau hyperphosphorylation, insulin resistance, oxidative stress, and synapse loss. Because different species of A?Os have been identified, a remaining question is which oligomer is the major pathogenic culprit. The possibility has been raised that more than one species plays a role. Despite some key unknowns, the clinical relevance of A?Os has been established, and new studies are beginning to point to co-morbidities such as diabetes and hypercholesterolemia as etiological factors. Because pathogenic A?Os appear early in the disease, they offer appealing targets for therapeutics and diagnostics. Promising therapeutic strategies include use of CNS insulin signaling enhancers to protect against the presence of toxins and elimination of the toxins through use of highly specific A?O antibodies. An AD-dependent accumulation of A?Os in CSF suggests their potential use as biomarkers and new A?O probes are opening the door to brain imaging. Overall, current evidence indicates that A? oligomers provide a substantive molecular basis for the cause, treatment and diagnosis of Alzheimer's disease.
Project description:IntroductionThe Alzheimer's Disease Neuroimaging Initiative (ADNI) has accumulated 15 years of clinical, neuroimaging, cognitive, biofluid biomarker and genetic data, and biofluid samples available to researchers, resulting in more than 3500 publications. This review covers studies from 2018 to 2020.MethodsWe identified 1442 publications using ADNI data by conventional search methods and selected impactful studies for inclusion.ResultsDisease progression studies supported pivotal roles for regional amyloid beta (Aβ) and tau deposition, and identified underlying genetic contributions to Alzheimer's disease (AD). Vascular disease, immune response, inflammation, resilience, and sex modulated disease course. Biologically coherent subgroups were identified at all clinical stages. Practical algorithms and methodological changes improved determination of Aβ status. Plasma Aβ, phosphorylated tau181, and neurofilament light were promising noninvasive biomarkers. Prognostic and diagnostic models were externally validated in ADNI but studies are limited by lack of ethnocultural cohort diversity.DiscussionADNI has had a profound impact in improving clinical trials for AD.
Project description:Alzheimer's disease (AD) is the most common cause of dementia in the elderly, clinically defined by progressive cognitive decline and pathologically, by brain atrophy, neuroinflammation, and accumulation of extracellular amyloid plaques and intracellular neurofibrillary tangles. Neurotechnological approaches, including optogenetics and deep brain stimulation, have exploded as new tools for not only the study of the brain but also for application in the treatment of neurological diseases. Here, we review the current state of AD therapeutics and recent advancements in both invasive and non-invasive neurotechnologies that can be used to ameliorate AD pathology, including neurostimulation via optogenetics, photobiomodulation, electrical stimulation, ultrasound stimulation, and magnetic neurostimulation, as well as nanotechnologies employing nanovectors, magnetic nanoparticles, and quantum dots. We also discuss the current challenges in developing these neurotechnological tools and the prospects for implementing them in the treatment of AD and other neurodegenerative diseases.