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Updated: May 3, 2026

SDS-PAGE/Immunoblot Detection of Aβ Multimers in Human Cortical Tissue Homogenates using Antigen-Epitope Retrieval
Published on: April 23, 2010
Differential changes in Aβ42 and Aβ40 with age
James Scott Miners1, Ruth Jones1, Seth Love1
1Dementia Research Group, School of Clinical Sciences, University of Bristol, Frenchay Hospital, Bristol, UK.
As people age, soluble amyloid-beta (Aβ) peptide levels decrease while insoluble Aβ42 increases. This shift, particularly after age 50, may elevate Alzheimer
Area of Science:
- Neuroscience
- Biochemistry
- Gerontology
Background:
- Amyloid-beta peptide (Aβ) accumulation in the brain is linked to Alzheimer's disease (AD).
- Soluble Aβ levels decline with age in healthy individuals, while insoluble Aβ increases.
- Previous research suggested a potential shift towards Aβ42 over Aβ40 with age.
Purpose of the Study:
- To quantify Aβ40 and Aβ42 levels in soluble and insoluble brain fractions across the human lifespan.
- To investigate age-related changes in the Aβ42:Aβ40 ratio in normal aging.
- To explore the implications of these changes for sporadic AD risk.
Main Methods:
- Analysis of human postmortem brain tissue from a cohort aged 16-95 years.
- Measurement of soluble and insoluble Aβ40 and Aβ42 using guanidine-extractable fractions.
- Comparison of peptide levels and ratios across different age groups.
Main Results:
- Absolute levels of soluble Aβ40, insoluble Aβ40, and soluble Aβ42 declined with age, primarily before 50 years.
- The Aβ42:Aβ40 ratio increased in both soluble and insoluble fractions after age 50.
- Insoluble Aβ42 showed a progressive increase with age.
Conclusions:
- Age-related changes in Aβ production or retention favor Aβ42 over Aβ40, especially after age 50.
- The increasing Aβ42:Aβ40 ratio with age is a significant factor in normal aging.
- Differential Aβ40 and Aβ42 dynamics likely contribute to the age-related risk of sporadic Alzheimer's disease.
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