Cargo of small extracellular vesicles from neuronal origin shows progression of dementia in individuals with Down syndrome

A new study led by researchers at University of Colorado Anschutz Medical Campus sheds light on a promising way to monitor Alzheimer’s disease (AD) progression in individuals with Down syndrome (DS). Diagnosing AD in people with DS can be especially difficult due to existing cognitive differences, but researchers have found a unique biological marker that could make early detection easier and more accurate.

The team focused on neuron-derived extracellular vesicles (NDEVs), tiny particles released by brain cells into the bloodstream. By isolating these vesicles from blood plasma, researchers measured the levels of several well-known Alzheimer’s-related proteins, including amyloid-β, Tau, and neurofilament light chain (NfL), using a highly sensitive method called single-molecule array technology.

What they found was striking: people with DS who were in the early, or “prodromal,” stage of Alzheimer’s had significantly higher levels of these proteins in their NDEVs compared to those who showed no signs of cognitive decline. Interestingly, the researchers also observed that middle-aged and older women with DS tended to have even higher biomarker levels than men.

Receiver operating characteristics (ROC) curves comparing the asymptomatic (aDS) group with prodromal AD dementia (pDS) group (green curve), with the dementia (dDS) (purple curve) group, and with the combined pDS and dDS groups (orange curve).

The blue curve depicts the ROC curve comparing the pDS to the dDS group. Area under the ROC curves (AUC) and 95% confidence intervals (95% CI) are presented for each curve. The ROC curves correspond to the best backward stepwise logistic regression model for each comparison.

This finding is important because it suggests that analyzing neuron-derived extracellular vesicles could help detect early signs of Alzheimer’s in people with Down syndrome, offering a less invasive and more accessible option than brain scans or spinal taps.

As scientists continue to explore how these vesicles reflect brain changes, NDEV-based blood tests may become a valuable tool in both clinical care and drug development for Alzheimer’s disease, especially in high-risk populations like those with Down syndrome.