Amyloid Beta (1-42), often simply referred to as Aβ1-42, has emerged as a crucial player in the pathogenesis of Alzheimer’s disease. It is one member of the family of amyloid beta peptides, and the Amyloid Beta peptide most prone to forming disease-promoting aggregations.
This article explores the significance of the Amyloid Beta (1-42) peptide as well as the Anti-Amyloid Beta (1-42) antibody in the context of neurological health, disease pathology, and as an emerging therapy.
Amyloid beta (Aβ) peptides are derived from the amyloid precursor protein (APP), an integral membrane protein expressed in various tissues, particularly in neuronal synapses. Amyloid beta peptides are central to Alzheimer's disease (AD) pathogenesis.
Aβ peptides, ranging from 37 to 49 amino acids, are generated through the amyloidogenic pathway via enzymatic cleavage which results in the formation of amyloid plaques characteristic of AD. These enzymes represent a potential therapeutic target for AD.
The normal production of amyloid beta proteins involves the cleavage of the amyloid precursor protein (APP) by α-secretase or β-secretase, followed by γ-secretase cleavage, resulting in the formation of soluble Aβ peptides. Normally, the amyloid beta proteins are cleared from the brain.
In contrast, pathological production of Aβ occurs when there is an imbalance in the processing of APP, leading to increased production or reduced clearance of Aβ peptides.
This imbalance may result from genetic or environmental factors, increasing age, vascular dysfunction, inflammation, or alterations in the amyloid beta clearance pathway, leading to the accumulation of Aβ peptides and their aggregation into insoluble fibrils. [7.]
The function of amyloid beta in healthy cells is not well-known, although its propensity for accumulating metal ions including zinc and copper hints at its role in metal sequestration. [6.]
The aggregation of these amyloid beta (Aβ) peptides into fibrils is central to Alzheimer's disease (AD) pathogenesis, though the exact correlation between amyloid plaques and neuronal loss remains unclear. Specifically, the amyloid plaques are composed of these amyloid beta fibrils.
Amyloid beta 1-42 (Aβ42) is one type of amyloid beta peptide, and a peptide implicated in Alzheimer's disease pathology.
It consists of 42 amino acids and is known for its propensity to form aggregates, leading to the development of amyloid plaques in the brain. The biochemical process of APP cleavage produces various forms of amyloid beta, but the 1-42 form is particularly significant due to its increased tendency to aggregate.
The neurotoxicity of Aβ1-42 is primarily due to its ability to form oligomers and fibrillar aggregates, which interfere with neuronal communication and disrupt synaptic function. These aggregates can also induce cellular stress responses, leading to neuronal damage and death.
The process of plaque formation involves the aggregation of Aβ1-42 peptides, which can attract and activate microglia and astrocytes, further contributing to neuroinflammation and neuronal degeneration. [5.]
Anti-Amyloid Beta 1-42 is an antibody against the amyloid beta 1-42 peptide, normally produced in the brain but developing pathological significance with reduced clearance. It is used in monoclonal antibody therapy.
Anti-amyloid beta antibodies are utilized therapeutically in Alzheimer's disease treatment by targeting and reducing the levels of amyloid beta plaques in the brain.
Administered intravenously at regular intervals, these monoclonal antibodies bind to amyloid beta aggregates, facilitating their clearance by the immune system and preventing further aggregation.
This mechanism helps to reduce the burden of amyloid beta plaques in the brain, thereby potentially slowing down disease progression and mitigating cognitive decline. However, the efficacy and safety of these therapies are still under investigation, and further research is needed to fully understand their impact on Alzheimer's disease pathology and clinical outcomes.
By reducing amyloid burden, these antibodies aim to slow down disease progression and mitigate cognitive decline. However, their therapeutic efficacy is still under scrutiny, with challenges such as the risk of adverse effects like amyloid-related imaging abnormalities (ARIA) and uncertainties regarding long-term benefits.
Despite these limitations, the success of anti-amyloid beta antibodies has paved the way for exploring novel therapeutic strategies targeting amyloid beta and other pathological pathways implicated in Alzheimer's disease.
The accurate detection and measurement of Amyloid Beta (1-42) peptides are pivotal for diagnosing and monitoring Alzheimer’s disease.
Lab testing for Amyloid Beta (1-42) peptides is primarily indicated in the evaluation of patients suspected of having Alzheimer’s disease or other forms of dementia.
The detection of Amyloid Beta (1-42) typically involves analyzing cerebrospinal fluid (CSF) samples for the presence of the amyloid-beta 1-42 peptides as well as other markers of AD pathogenesis. [2.]
It is also available as a blood test, which commonly assesses the ratio of amyloid Beta (1-42) to amyloid Beta (1-40) peptide levels. [1.] This is intended to be an adjunctive test in the diagnosis of AD along with cognitive performance tests and PET neuroimaging scans.
Amyloid Beta (1-42) testing is highly specialized. In contrast, genetic testing may provide insight into individuals with greater risk of developing Alzheimer’s disease and provide opportunities to implement diet and lifestyle strategies to protect neurological and cognitive health.
The APOE genetic test for Alzheimer's disease is clinically valuable in assessing an individual's risk of developing the condition.
Specifically, this test identifies variations in the apolipoprotein E (APOE) gene, with the ε4 allele being associated with increased susceptibility to Alzheimer's disease, while the ε2 allele is linked to a reduced risk.
Possessing the ε4 allele does not guarantee the development of Alzheimer's disease, nor does the absence of this allele rule out the possibility of developing the condition.
Additionally, the APOE genetic test does not provide a definitive diagnosis of Alzheimer's disease: rather, it offers valuable information for risk assessment and informing clinical management decisions such as lifestyle modifications and potential participation in clinical trials for disease-modifying therapies.
The APOE4 allele confers an increased risk of Alzheimer's disease through several mechanisms.
Firstly, the presence of the APOE4 allele is associated with higher levels of amyloid-beta deposition in the brain, which is a hallmark characteristic of Alzheimer's disease pathology.
This allele may also contribute to impaired clearance of amyloid-beta from the brain, leading to its accumulation and the formation of plaques, which are toxic to neurons.
APOE4 has been implicated in promoting neuroinflammation, oxidative stress, and altered lipid metabolism in the brain, which are processes involved in neuronal damage and degeneration. [10.]
Furthermore, APOE4 may affect synaptic plasticity and neuronal repair mechanisms, further exacerbating the neurodegenerative process.
Conversely, the APOE2 gene is associated with a decreased risk of developing Alzheimer’s disease.
Individuals interested in testing their genes for the presence of APOE4 should consult with a healthcare professional to discuss the implications of genetic test results and implement an individualized plan.
Click here to compare tests and order testing for the APOE4 gene.
[1.] 505725: Beta Amyloid 42/40 Ratio, Plasma | Labcorp. www.labcorp.com. Accessed March 28, 2024. https://www.labcorp.com/tests/505725/beta-amyloid-42-40-ratio-plasma
[2.] ADEVL - Overview: Alzheimer Disease Evaluation, Spinal Fluid. @mayocliniclabs. Published 2022. Accessed March 28, 2024. https://www.mayocliniclabs.com/test-catalog/overview/607273
[3.] Chen G, Xu T, Yan Y, et al. Amyloid beta: structure, Biology and structure-based Therapeutic Development. Acta Pharmacologica Sinica. 2017;38(9):1205-1235. doi:https://doi.org/10.1038/aps.2017.28
[4.] Cummings J. Anti-Amyloid Monoclonal Antibodies are Transformative Treatments that Redefine Alzheimer's Disease Therapeutics. Drugs. 2023 May;83(7):569-576. doi: 10.1007/s40265-023-01858-9. Epub 2023 Apr 15. PMID: 37060386; PMCID: PMC10195708.
[5.] Meraz-Ríos MA, Toral-Rios D, Franco-Bocanegra D, Villeda-Hernández J, Campos-Peña V. Inflammatory process in Alzheimer's Disease. Front Integr Neurosci. 2013 Aug 13;7:59. doi: 10.3389/fnint.2013.00059. PMID: 23964211; PMCID: PMC3741576.
[6.] Moreira PI, Akihiko Nunomura, Honda K, et al. The Key Role of Oxidative Stress in Alzheimer’s Disease. Elsevier eBooks. Published online January 1, 2007:267-281. doi:https://doi.org/10.1016/b978-044452809-4/50153-8
[7.] Murphy MP, LeVine H 3rd. Alzheimer's disease and the amyloid-beta peptide. J Alzheimers Dis. 2010;19(1):311-23. doi: 10.3233/JAD-2010-1221. PMID: 20061647; PMCID: PMC2813509.
[8.] Raulin AC, Doss SV, Trottier ZA, Ikezu TC, Bu G, Liu CC. ApoE in Alzheimer’s disease: pathophysiology and therapeutic strategies. Molecular Neurodegeneration. 2022;17(1). doi:https://doi.org/10.1186/s13024-022-00574-4
[9.] Roher AE, Lowenson JD, Clarke S, Woods AS, Cotter RJ, Gowing E, Ball MJ. beta-Amyloid-(1-42) is a major component of cerebrovascular amyloid deposits: implications for the pathology of Alzheimer disease. Proc Natl Acad Sci U S A. 1993 Nov 15;90(22):10836-40. doi: 10.1073/pnas.90.22.10836. PMID: 8248178; PMCID: PMC47873.
[10.] Sienski G, Narayan P, Bonner JM, Kory N, Boland S, Arczewska AA, Ralvenius WT, Akay L, Lockshin E, He L, Milo B, Graziosi A, Baru V, Lewis CA, Kellis M, Sabatini DM, Tsai LH, Lindquist S. APOE4 disrupts intracellular lipid homeostasis in human iPSC-derived glia. Sci Transl Med. 2021 Mar 3;13(583):eaaz4564. doi: 10.1126/scitranslmed.aaz4564. PMID: 33658354; PMCID: PMC8218593.
[11.] van Dyck CH. Anti-Amyloid-β Monoclonal Antibodies for Alzheimer’s Disease: Pitfalls and Promise. Biological Psychiatry. 2018;83(4):311-319. doi:https://doi.org/10.1016/j.biopsych.2017.08.010