Amyloid beta (Aβ) is a peptide of 39-43 amino acids found in large amounts and forming deposits in the brain tissue of patients with Alzheimer's disease (AD). For this reason, it has been implicated in the pathophysiology of damage observed in this type of dementia. However, the role of Aβ in the pathophysiology of AD is not yet precisely understood. Aβ has been experimentally shown to have a wide range of toxic mechanisms in vivo and in vitro, such as excitotoxicity, mitochondrial alterations, synaptic dysfunction, altered calcium homeostasis, oxidative stress, and so forth. In contrast, Aβ has also shown some interesting neuroprotective and physiological properties under certain experimental conditions, suggesting that both physiological and pathological roles of Aβ may depend on several factors. In this paper, we reviewed both toxic and protective mechanisms of Aβ to further explore what their potential roles could be in the pathophysiology of AD. The complete understanding of such apparently opposed effects will also be an important guide for the therapeutic efforts coming in the future.
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http://dx.doi.org/10.1155/2014/795375 | DOI Listing |
Brain
January 2025
Translational Neuroimaging Laboratory, Montreal Neurological Institute, H3A 2B4, Montreal, Canada.
Plasma phosphorylated tau biomarkers open unprecedented opportunities for identifying carriers of Alzheimer's disease pathophysiology in early disease stages using minimally invasive techniques. Plasma p-tau biomarkers are believed to reflect tau phosphorylation and secretion. However, it remains unclear to what extent the magnitude of plasma p-tau abnormalities reflects neuronal network disturbance in the form of cognitive impairment.
View Article and Find Full Text PDFJ Vis Exp
January 2025
Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Henry and Allison McCance Center for Brain Health, Department of Neurology, Massachusetts General Hospital, Harvard Medical School;
A method to quantitate the stabilization of Mitochondria-Associated endoplasmic reticulum Membranes (MAMs) in a 3-dimensional (3D) neural model of Alzheimer's disease (AD) is presented here. To begin, fresh human neuro progenitor ReN cells expressing β-amyloid precursor protein (APP) containing familial Alzheimer's disease (FAD) or naïve ReN cells are grown in thin (1:100) Matrigel-coated tissue culture plates. After the cells reach confluency, these are electroporated with expression plasmids encoding red fluorescence protein (RFP)-conjugated mitochondria-binding sequence of AKAP1(34-63) (Mito-RFP) that detects mitochondria or constitutive MAM stabilizers MAM 1X or MAM 9X that stabilize tight (6 nm ± 1 nm gap width) or loose (24 nm ± 3 nm gap width) MAMs, respectively.
View Article and Find Full Text PDFAlzheimers Dement
January 2025
Unitat de Trastorns Cognitius, Cognition and Behavior Study Group, Hospital Universitari Santa Maria Universitat de Lleida, Lleida, Spain.
Introduction: Changes in sleep physiology can predate cognitive symptoms by decades in persons with Alzheimer's disease (AD), but it remains unclear which sleep characteristics predict cognitive and neurodegenerative changes after AD onset.
Methods: Using data from a prospective cohort of mild to moderate AD (n = 60), we analyzed non-rapid eye movement sleep spindles and slow oscillations (SOs) at baseline and their associations with baseline amyloid beta (Aβ) and tau and with cognition from baseline to 3-year follow-up.
Results: Higher spindle and SO activity predicted significant changes in Aβ and tau at baseline, lower Alzheimer's Disease Assessment Scale Cognitive Subscale (better cognitive performance) score, and higher Mini-Mental State Examination score from baseline to 36 months.
Curr Alzheimer Res
January 2025
Metabolic Syndrome Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
Extracellular vesicles (EVs) are nano-sized membranous particles that are secreted by various cell types and play a critical role in intercellular communication. Their unique properties and remarkable ability to deliver bioactive cargo to target cells have made them promising tools in the treatment of various diseases, including Alzheimer's disease (AD). AD is a devastating neurodegenerative disease characterized by progressive cognitive decline and neuropathological hallmarks, such as amyloid-beta plaques and neurofibrillary tangles.
View Article and Find Full Text PDFAlzheimers Dement
January 2025
Department of Neuroscience, City University of Hong Kong, Hong Kong, Hong Kong.
Introduction: Antisense oligonucleotides (ASOs) have shown promise in reducing amyloid precursor protein (APP) levels in neurons, but their effects in astrocytes, key contributors to neurodegenerative diseases, remain unclear. This study evaluates the efficacy of APP ASOs in astrocytes derived from an individual with Down syndrome (DS), a population at high risk for Alzheimer's disease (AD).
Methods: Human induced pluripotent stem cells (hiPSCs) from a healthy individual and an individual with DS were differentiated into astrocytes.
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