At the Icahn School of Medicine at Mount Sinai in Manhattan, researchers say they have zeroed in on tiny nanoparticles in the blood, nicknamed “SECmeres,” that carry brain-specific RNA signals and might eventually power a simple blood test for Alzheimer’s disease. The work, announced June 22, comes from paired analyses of blood and brain tissue that found SECmeres delivered clearer Alzheimer’s-related signals than standard extracellular vesicles. For now, the scientists are stressing this is an early proof of concept, not something ready for the clinic.
Study published and what SECmeres are
The peer-reviewed findings appear in Nature Communications, where the team describes sub-50 nm small extracellular particles, dubbed SECmeres, that are enriched for brain markers and RNAs. In the paper, RNAs associated with SECmeres separated neuropathologically confirmed Alzheimer’s cases from controls with greater statistical significance than RNAs found in small extracellular vesicles, while large extracellular vesicles showed no meaningful difference. An estimated 55 million people worldwide are living with dementia, highlighting why less invasive diagnostic tools could matter, according to Alzheimer’s Disease International.
Researchers' take
“Our study demonstrates that blood EVPs carry brain-specific RNA information that could be used for liquid biopsy approaches, pending validation in larger blinded clinical trials,” said Navneet Dogra, PhD, in a press release from Mount Sinai. The release notes that the team believes EVP-derived RNAs may capture disease-related changes earlier than protein markers or visible pathology. Co-corresponding author Panos Roussos adds in the same release that the data support developing RNA-based liquid-biopsy assays for Alzheimer’s.
How the team did it
To get there, the group used a new benchtop isolation method called SECrifuge to fractionate extracellular vesicle particles from human brain tissue and blood, then ran proteomic and transcriptomic profiling to track cellular origins and disease-linked signals, according to Nature Communications. The study reports EVP isolates from neuropathologically confirmed Alzheimer’s and non-Alzheimer’s subjects, along with additional validation datasets from brain homogenates and induced pluripotent stem cell (iPSC) neurons. Single-nucleus RNA sequencing deconvolution suggested SECmeres are enriched for brain endothelial transcripts, while small extracellular vesicles carried RNAs from a wider mix of brain cell types.
How this fits with existing tests
Regulators are already edging into blood-based testing for the disease. Last year the U.S. Food and Drug Administration cleared the first blood-based protein diagnostic that uses the pTau217/β-amyloid 1-42 plasma ratio, a step toward blood tests for Alzheimer’s in symptomatic adults. The FDA cleared that protein-ratio assay for use alongside a clinical evaluation. The Mount Sinai work takes a different angle by profiling RNA cargo in distinct nanoparticle subpopulations, and the authors argue those RNA signatures could flag disease biology that protein assays might miss in the earliest phases.
Next steps and caveats
The authors repeatedly describe this as a proof-of-concept effort and note that SECmere-based RNA signatures will need to be tested in larger, blinded clinical trials before anyone talks about routine clinical use, according to the Mount Sinai release. The Nature paper also points to technical constraints and modest cohort sizes, while presenting SECrifuge as a rapid, reproducible isolation method that can be scaled up in future studies. Turning these molecular readouts into affordable, regulated tests will require multi-center validation and a full regulatory review process.
For New Yorkers, it is a reminder that big biomarker advances often start in neighborhood labs and only reach patients after years of follow-up work. Mount Sinai’s findings move the conversation forward on where RNA-based, minimally invasive diagnostics might eventually fit into Alzheimer’s care, even as clinicians and regulators keep debating how and when to bring new tools into real-world practice.
