Researchers at the Icahn School of Medicine at Mount Sinai in New York say they have identified new RNA biomarkers in blood that could one day change how Alzheimer’s is diagnosed. The findings were published in the journal Nature Communications and may help lead to a simple, accessible blood test that could detect the disease before the first symptoms of dementia appear.
In the study, the team developed a new, relatively simple and inexpensive method for isolating tiny particles that originate in brain cells and enter the bloodstream. These particles, called vesicles and extracellular particles, or EVPs, can cross the blood-brain barrier and carry biological information about what is happening in the brain.
The researchers examined blood and brain tissue samples from people diagnosed with Alzheimer’s as well as people without the disease. They analyzed gene expression patterns and the cell sources of the different RNA markers, and identified blood RNA signals originating from several brain cell types, including neurons, supportive nerve cells and immune cells in the brain.
According to the researchers, the RNA patterns they found were similar to changes seen in Alzheimer’s brain tissue, strengthening the idea that blood could serve as a window into brain changes. Today, diagnosis relies mainly on clinical evaluation, memory tests, advanced brain imaging such as PET, or spinal fluid tests, which are expensive, invasive or not widely available. The scientists say a future RNA-based blood test could be faster, less invasive and more accessible, but they stress the work is still preliminary and needs larger studies before it can be used routinely. Experts say earlier diagnosis could support closer monitoring, earlier treatment adjustments and lifestyle changes, and the need for such tools is growing as Alzheimer’s remains the world’s most common cause of dementia, affecting tens of millions of people.
