Plasma pyroglutamate-modified amyloid beta differentiates amyloid pathology

Area of Science:

• Biochemistry
• Neuroscience
• Medical Diagnostics

Background:

• Pyroglutamate-modified amyloid beta (AβpE3) is linked to Alzheimer's disease (AD) plaque pathology in the brain.
• An ultra-high-sensitive assay is crucial for detecting AβpE3-40, a specific form of this biomarker.

Purpose of the Study:

• To quantify AβpE3-40 in human plasma.
• To evaluate the correlation between plasma AβpE3-40 levels and amyloid PET imaging results.

Main Methods:

• Immunomagnetic reduction assay was employed for AβpE3-40 quantification in plasma samples from 46 participants.
• Plasma AβpE3-40 concentrations were compared with 18F-florbetapir PET imaging results.

Main Results:

• Plasma AβpE3-40 levels were significantly higher in participants with positive amyloid PET scans (91.6 ± 54.6 fg/mL) compared to those with negative scans (44.1 ± 28.2 fg/mL).
• A cutoff value of 55.5 fg/mL demonstrated 83.3% sensitivity and 71.4% specificity for discriminating between PET-positive and PET-negative individuals.
• A moderate positive correlation (r = 0.437) was observed between AβpE3-40 concentration and PET standardized uptake value ratio.

Conclusions:

• Plasma AβpE3-40 detection is feasible for identifying individuals with Aβ plaque pathology.
• Further research is warranted to explore the utility of AβpE3-40 for screening pre-clinical Alzheimer's disease subjects.