Japanese researchers have identified molecules in the blood that can help distinguish patients with Alzheimer’s disease (AD) from those with mild cognitive impairment (MCI) as well as from healthy individuals.1
In addition to examining symptoms, neurologists detect AD by measuring toxic proteins in the brain and the cerebrospinal fluid. In search of a less-invasive approach, researchers from Okayama University used blood to investigate proteins that may aid with diagnosis. The team developed a method of separating peptides from blood and transferring them onto a chip to be analyzed on a sensitive mass spectrometer.
Figure 1: The graph shows blood peptide levels (boxes) in the three groups and how higher levels of the peptides coincide with lower MMSE (cognitive) scores (circles). Courtesy Okayama University.
When blood peptides from AD patients, MCI patients, and healthy individuals were compared, they did indeed appear different, with a set of four showing the most varied patterns. The peptides appeared to be high in the AD patients, moderate in the MCI patients, and low in healthy individuals.
These findings corresponded with other diagnostic tests used for AD. Individuals with higher peptides did worse on a clinical cognitive performance test, and brain scans revealed that these same individuals also showed an accumulation of toxic proteins in their brains. A deeper dive into the biology of these peptides hinted that they were linked to inflammation in the brain.
“The present study provides a new diagnostic biomarker set for MCI and AD by a new peptidome technology, but also suggests an important pathomechanism of AD for neuroinflammation,” the researchers wrote.
Reference
1. Abe K, Shang J, Shi X, et al. A new serum biomarker set to detect mild cognitive impairment and Alzheimer’s disease by peptidome technology. J Alzheimers Dis. 2020;73(1):217–227; doi: 10.3233/JAD-191016.
Featured image: An example of a healthy brain without Aβ, the toxic protein (A), and an AD brain with Aβ (B). Patients with Aβ-positive brains also had higher blood peptide markers. Image courtesy Okayama University.
