As indicators that measure disease processes inside the body, blood-based biomarkers have great potential for use as clinical screening tools and for research. In a new article published in the Brain journal, a team of researchers led by Caroline Graff (Karolinska Institute, Sweden), identify a panel of blood-based biomarkers that may be able to detect Alzheimer’s disease (AD) pathology in presymptomatic individuals. People who carry mutations in genes such as APP, PSEN1 and PSEN2 are at high risk of developing an early onset, inherited form of AD known as “autosomal dominant AD”, or ADAD. Studying the levels of blood-based biomarkers in people with a genetic predisposition to ADAD offers an opportunity to evaluate the accuracy and specificity of these biomarkers in the very earliest stages of disease, before symptoms develop. These learnings could have wider implications for research on the most common form of AD, which is not directly caused by inherited genetic changes.
In their new publication, Prof. Graff and colleagues evaluated blood plasma samples from participants in a Swedish study of inherited AD, measuring the concentration of the pTau181, tTau, NfL and GFAP biomarkers over an average period of 6 years (ranging from 0-23 years) in 33 people carrying ADAD mutations, compared to 42 people without ADAD mutations. Mapping the results to disease progression studies, they found that changes in the GFAP biomarker could be detected around 10 years before symptoms occurred, followed by pTau181 and NfL. Conversely, tTau was unable to discriminate between people who would later develop ADAD, and unaffected individuals. Further studies are now required, to replicate these findings in cohorts with larger numbers of participants.
