Alzheimer’s disease was first diagnosed postmortem by medical professionals by observing physical changes in the brain such as protein plaques and neurological tangles under a microscope before extensive research.
Researchers are now developing biomarkers that measure protein accumulations in the blood, to detect early signs of dementia in patients. These biomarkers can track brain pathology and identify those at risk for dementia later in life. But more research is needed to understand more about associations between blood biomarkers and dementia risk. Because current studies have primarily focused on older adults and have not followed individuals over time.
Alzheimer’s disease and related dementia are influenced by some factors such as age and genetics. Researchers should try to fill gaps in understanding biomarker trends and other factors that increase the risk of disease progression to create accurate blood tests for these conditions. This knowledge can help them make some effective strategies that can prevent and preserve brain health.
A recent study has found that certain blood biomarkers of Alzheimer’s disease pathology and neurodegeneration in midlife and late life have strong associations with late-life dementia, especially a protein called neurofilament light chain (NfL). This research can provide insights into how to maintain brain function in people at risk for dementia, monitor disease progression, or identify individuals who may benefit from treatment. The findings were published in JAMA and accompanied by an editorial discussing the findings.
In this study, researchers used data of 1525 participants from the Atherosclerosis Risk in Communities Neurocognitive Study (ARIC-NCS). This study was initially focused on atherosclerosis but now links cardiovascular risk and dementia. Researchers observed participants’ blood samples. They also studied more about their age, race and education level.
When researchers observed the collected data, they found that age decreased Amyloid-beta (Aβ) peptides 42 (Aβ42) and 40 (Aβ40). On the other hand, it increased Phosphorylated tau-181 p-tau181, Glial Fibrillary Acidic Protein (GFAP) and NfL. These findings indicate neurodegeneration. They also found that midlife hypertension and diabetes were associated with a faster rise in NfL and GFAP that shows a strong association with late-life dementia.
The study reveals that disease-related changes can be detected in the blood nearly 20 years before dementia emerges at the population level. But there is a need for further research to understand more about specific biomarkers for individual diagnosis.
Reference Link:
Yifei Lu et al, Changes in Alzheimer Disease Blood Biomarkers and Associations With Incident All-Cause Dementia, JAMA (2024). 
Stephen Salloway et al, Are Blood Tests for Alzheimer Disease Ready for Prime Time?, JAMA (2024). 
