A biomarker, or biological marker, is a measurable indication indicator of a disease. AIBL researchers use different types of biomarkers in combination with demographic, clinical and lifestyle data to better understand the nature of Alzheimer’s disease, measure its prevalence and progression within the study cohort and develop tools such as neuroimaging markers or screening tests.
Every AIBL study participant was asked to provide an 80ml sample of blood at study commencement. A subset of the cohort also underwent neuroimaging and provided cerebrospinal fluid (CSF) samples.
Blood and CSF Biomarkers
A portion of the blood sample was used in a range of baseline testing from clinical pathology screening to novel biomarker examinations. 0.5ml of whole blood was forwarded for apolipoprotein E genotyping and another 0.59ml of whole blood was stored in liquid nitrogen. The remaining blood was fractionated into serum, plasma, platelets, red blood cell, white blood cell (dH20) and white blood cell (RNAlater, Ambion) and stored in liquid nitrogen.
Stored blood samples were sourced from 3 different tube types: lithium-heparin tubes, EDTA tubes with added prostaglandin E1 (Sapphire Biosciences, 33.3ng/ml), and serum tubes.
Biomarker Research Stream Highlights
- Developed blood biomarker panels diagnostic of disease and prognostic for brain β-amyloid level and therefore likelihood of disease progression. With further improvement these studies provide the basis for a realistic expectation that a blood based first step screening test for AD is achievable.
- In collaboration with the CRC for Mental Health have identified via 2D gel electrophoresis biomarkers in plasma that distinguish between Alzheimer’s disease and control subjects. As the biomarkers are reflective of the amyloid load in the brain they have the potential to detect Alzheimer’s disease at a preclinical stage of the condition. Further validation studies are in progress.
- Researchers from The University of Melbourne and AIBL have developed a method of screening patients at risk of Alzheimer’s disease. The method is based on detecting the expression levels of selected miRNA extracted from small volumes of blood samples. This novel method provides a sensitive means of diagnosing Alzheimer’s disease at an early stage (87% sensitivity; 77% specificity). The method has been validated in clinical samples from patients in the AIBL study.