Blood Markers Could Help Spot Early Alzheimer’s Risk

Research indicates that structural changes in the brain are linked with blood biomarkers of Alzheimer’s disease in clinical study populations, but information from cognitively healthy people has been limited.

To address that gap, Martina Valletta, MD, a PhD student at Karolinska Institutet in Stockholm, Sweden, and her colleagues examined how cerebrovascular burden and brain volume changes relate to Alzheimer’s blood biomarkers. They shared the findings at a recent European Academy of Neurology Congress.

The team studied 372 older adults without dementia. They measured blood levels of amyloid-β42/40 (Aβ42/40), total tau (t-tau), phosphorylated tau (p-tau)181 and 217, glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL). Brain MRI scans were obtained at baseline, year 3, and year 6.

Using linear mixed models, the researchers assessed associations between changes in Alzheimer’s blood biomarkers and the volumes of the ventricles, amygdala, hippocampus, total brain tissue, and white matter hyperintensities.

The findings showed that faster hippocampal volume loss was associated with higher levels of p-tau217 and p-tau181 in the blood. The data also suggested that p-tau217 was linked to a smaller amygdala. Higher GFAP levels were associated with more rapid enlargement of the ventricles, faster hippocampal shrinkage, and a decline in total brain tissue volume.

“In cognitively healthy older adults, elevated blood levels of p-tau isoforms were linked to decline in AD-specific regions, whereas NfL and GFAP were associated with widespread atrophy and NfL also with WMH [white matter hyperintensity] accumulation,” the study team concluded.

“These findings suggest that altered AD blood biomarkers may capture the earliest stages of dementia-related brain changes in the general population,” they added.

References

European Association of Neurology Annual Meeting. Abstract No. OPR-009.