amyloid-pathology

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Amyloid Pathology

Overview

flowchart TD Amyloid_Pathology["Amyloid Pathology"] -->|"biomarker for"| Alzheimer_S["Alzheimer'S"] amyloid_pathology["amyloid pathology"] -->|"drives"| Alzheimer_s_Disease["Alzheimer's Disease"] AMYLOID_PATHOLOGY["AMYLOID PATHOLOGY"] -->|"associated with"| ALZHEIMER_S_DISEASE["ALZHEIMER'S DISEASE"] Amyloid_Pathology["Amyloid Pathology"] -->|"involved in"| Alzheimer_S_Disease["Alzheimer'S Disease"] Amyloid_Pathology["Amyloid Pathology"] -->|"biomarker for"| Alzheimer_s_Disease["Alzheimer's Disease"] Amyloid_Pathology["Amyloid Pathology"] -->|"associated with"| Tau_Pathology["Tau Pathology"] Amyloid_Pathology["Amyloid Pathology"] -->|"interacts with"| Neuroinflammation["Neuroinflammation"] Amyloid_pathology["Amyloid pathology"] -->|"contributes to"| Alzheimer_s_Disease["Alzheimer's Disease"] amyloid_pathology["amyloid pathology"] -->|"interacts with"| mitochondrial_dysfunction["mitochondrial dysfunction"] Ptau217["Ptau217"] -->|"biomarker for"| Amyloid_Pathology["Amyloid Pathology"] ABETA42["ABETA42"] -->|"component of"| Amyloid_Pathology["Amyloid Pathology"] ABETA40["ABETA40"] -->|"component of"| Amyloid_Pathology["Amyloid Pathology"] APOE4["APOE4"] -->|"causes"| amyloid_pathology["amyloid pathology"] APOE4["APOE4"] -->|"upregulates"| Amyloid_Pathology["Amyloid Pathology"] style amyloid_pathology fill:#4fc3f7,stroke:#333,color:#000

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Amyloid Pathology

Overview

Mermaid diagram (expand to render)

Amyloid pathology refers to the accumulation and deposition of misfolded proteins in tissues and organs. In Alzheimer's disease, [amyloid-beta](/proteins/amyloid-beta) (Abeta) peptides aggregate to form plaques, which are considered a central pathological feature of the disease [1]. [@charidimou2015]

Amyloid-Beta

Normal Physiology

Amyloid-beta is a peptide derived from the [amyloid precursor protein](/entities/app-protein) (APP) through sequential proteolytic cleavage by [beta-secretase](/entities/bace1) (BACE) and [gamma-secretase](/entities/gamma-secretase) [2]. The amyloidogenic processing pathway generates Aβ peptides of varying lengths, with Aβ40 being the most abundant species and Aβ42 being more aggregation-prone due to two additional hydrophobic residues at the C-terminus [3]. [@weller2000]

Aggregation Process

The aggregation of Aβ follows a nucleation-dependent polymerization mechanism: [@jellinger2005]

Monomeric Aβ → Oligomers → Protofibrils → Fibrils → Plaques [4]
Soluble oligomers are considered more toxic than plaques [5]
Different Aβ species: Aβ40, Aβ42, Aβ43 [3]
The critical concentration for nucleation is lower for Aβ42 compared to Aβ40 [6]

Plaque Types

Core Amyloid Plaques

Dense-core plaques
Contain Aβ fibrils in cross-β sheet conformation [7]
Surrounded by dystrophic neurites
Associated with neuritic plaques in AD diagnosis [8]

Diffuse Plaques

Non-fibrillar Aβ deposits
Less well-defined borders
May be earlier stage of plaque formation [9]
Can be found in cognitively normal individuals [10]

Vascular Amyloid (CAA)

Deposited in cerebral blood vessels
Associated with hemorrhage risk [11]
Perivascular clearance impaired [12]
CAA affects ~80% of AD cases to some degree [13]

Pathogenic Mechanisms

Synaptic Toxicity

Soluble Aβ oligomers disrupt synaptic function [14]
Loss of [dendritic spines](/cell-types/dendritic-spines) [15]
Impaired neurotransmitter release [16]
Synaptic loss correlates strongly with cognitive decline [17]

Calcium Dysregulation

Aβ forms membrane pores allowing calcium influx [18]
Mitochondrial dysfunction from calcium overload [19]
Cellular energy deficits and ATP depletion [20]

Neuroinflammation

Microglial activation via pattern recognition receptors [21]
Cytokine release (IL-1β, TNF-α, IL-6) [22]
Chronic inflammatory response contributes to neurodegeneration [23]
Trem2 variants affect microglial response to amyloid [24]

Tau Pathology

Amyloid triggers [tau](/proteins/tau) pathology [25]
Spread along neural networks [26]
Correlation with cognitive decline [27]
Amyloid-tau interaction is synergistic [28]

Structural Biology of Amyloid Fibrils

Cross-β Sheet Structure

Amyloid fibrils adopt a characteristic cross-β sheet quaternary structure where β-strands run perpendicular to the fibril axis [7]. This structure is stabilized by hydrogen bonds between backbone amide and carbonyl groups, as well as side-chain interactions. Different Aβ strains can adopt distinct conformations, potentially explaining phenotypic heterogeneity in AD [29]. [@shankar2008]

Polymorphism

Aβ fibrils exhibit structural polymorphism, with distinct morphologies observed in different individuals and brain regions [30]. This polymorphism may influence disease progression and therapeutic response [31]. [@spires2005]

Aggregation Kinetics

Nucleation and Elongation

The aggregation process follows sigmoidal kinetics with three phases: [@kamenetz2003]

Nucleation (lag phase): Formation of critical nucleus [32]

Elongation (growth phase): Addition of monomers to fibril ends [33]

Equilibrium (plateau phase): Dynamic balance [34]

Factors Affecting Aggregation

Concentration: Higher Aβ concentration accelerates aggregation [35]
pH: Optimal aggregation at physiological pH [36]
Metal ions: Cu²⁺ and Zn²⁺ promote aggregation [37]
Post-translational modifications: Oxidation, phosphorylation affect kinetics [38]

Therapeutic Approaches

Immunotherapies

Aducanumab: Anti-Aβ antibody (withdrawn from market) [39]
[Lecanemab](/entities/lecanemab): Anti-protofibril antibody (approved for early AD) [40]
[Donanemab](/entities/donanemab): Anti-plaque antibody (approved for early AD) [41]
Donanemab demonstrated significant plaque reduction in TRAILBLAZER-ALZ 2 trial [42]

Secretase Inhibitors

BACE inhibitors: Failed due to adverse effects [43]
Gamma-secretase modulators: In development [44]

Anti-Aggregation Strategies

Small molecules to prevent aggregation [45]
Peptide-based inhibitors [46]
Chaperone proteins (Hsp70, Hsp90) [47]

Recent Research Updates (2024-2026)

This section highlights recent publications relevant to this mechanism. [@terry1991]

[A novel Mediterranean diet-inspired supplement reduces hippocampal amyloid deposits and microglial activation through the modulation of the microbiota gut-brain axis in 5xFAD mice.](https://pubmed.ncbi.nlm.nih.gov/41527932/) (2026) - Gut Microbes
[lncRNAs: key player in Aβ deposition.](https://pubmed.ncbi.nlm.nih.gov/41784271/) (2026) - RNA Biol
[GPR3 in neuro-metabolic-immune-reproductive nexus - a potential therapeutic target for Multi-System diseases.](https://pubmed.ncbi.nlm.nih.gov/41574602/) (2026) - Ann Med
[Engineering nanobodies for drug delivery systems in Alzheimer's disease.](https://pubmed.ncbi.nlm.nih.gov/41568664/) (2026) - Artif Cells Nanomed Biotechnol
[Control analysis of deep brain stimulation and optogenetics for Alzheimer's disease under the computational cortex model.](https://pubmed.ncbi.nlm.nih.gov/41306192/) (2026) - Cogn Neurodyn

Additional evidence sources: [@arispe1993] [@wang1992] [@mattson1997] [@hickman2010] [@griffin1998] [@heppner2015] [@griciuc2013] [@musiek2015] [@braak2011] [@nelson2012] [@ittner2018] [@cohen2023] [@guo2023] [@riek2016] [@knowles2009] [@carulla2005] [@sengupta2023] [@lomakin1996] [@gursky2000] [@bush2002] [@crouch2009] [@sevigny2016] [@van2023] [@mintun2021] [@sims2023] [@bace2018] [@bales2021] [@lupi2008] [@soto1996] [@evans2006]

Pathway Diagram

The following diagram shows the key molecular relationships involving amyloid-pathology discovered through SciDEX knowledge graph analysis:

Mermaid diagram (expand to render)

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amyloid-pathology

Amyloid Pathology

Overview

Amyloid Pathology

Overview

Amyloid-Beta

Normal Physiology

Aggregation Process

Plaque Types

Core Amyloid Plaques

Diffuse Plaques

Vascular Amyloid (CAA)

Pathogenic Mechanisms

Synaptic Toxicity

Calcium Dysregulation

Neuroinflammation

Tau Pathology

Structural Biology of Amyloid Fibrils

Cross-β Sheet Structure

Polymorphism

Aggregation Kinetics

Nucleation and Elongation

Factors Affecting Aggregation

Therapeutic Approaches

Immunotherapies

Secretase Inhibitors

Anti-Aggregation Strategies

Recent Research Updates (2024-2026)

See Also

Pathway Diagram