Could RNA in Blood Nanoparticles Enable Earlier Diagnosis of Alzheimer Disease?

Psychiatric diseases lack precision diagnostics and blood-based biomarkers, in contrast with several cancers for which biomarkers existed, according to Navneet Dogra, PhD. Definitive diagnosis of Alzheimer disease remains postmortem, but Dogra shared his research on earlier biomarker testing for dementia.

Dogra's laboratory examined the brain microenvironment of patients with Alzheimer disease alongside their matched blood to determine how much brain-derived material crossed the blood-brain barrier and reached circulation.¹ The work centered on exosomes—nanoparticles about 1000 times smaller than the thickness of a hair. Neurons and other cells shed exosomes into bodily fluids, where they circulate. The laboratory studied what these particles carried and whether that cargo could support diagnosis of Alzheimer disease.

No diagnostic test was available when the study began, but the first diagnostic test for Alzheimer disease, a protein-based assay, has since been cleared by the US Food and Drug Administration.² The current approach targets RNA instead of protein. Dogra suggested that "if the dynamic changes in the cells can be traced through RNA, we may be able to understand the pathogenesis even before proteins." Future work would define the molecular trajectory of RNA over time in patients with Alzheimer disease, filling the gap left by the study's single comparison of confirmed cases with controls.

Current techniques for diagnosis carry practical limitations. Lumbar puncture offered a closer view of the brain and identified certain markers, but monitoring over time required repeated punctures, and positron emission tomography required specialized skill and imaging machines. A blood draw, by contrast, is common in practice and easier to repeat across years. Dogra highlighted blood tests as a potential less invasive option, noting, "as we are progressing toward precision medicine, blood seems to be the choice, the minimally invasive choice at least."

Dr Dogra is an assistant professor at the Icahn School of Medicine at Mount Sinai.

References

1. Gonzalez-Kozlova E, Tichkule S, Nose Y, et al. SECmeres outperform extracellular vesicles as potential blood RNA biomarkers for Alzheimer's disease. Nat Commun. 2026;17(1):5453.

2. FDA clears first blood test used in diagnosing Alzheimer's disease. Press release. May 16, 2025. Accessed October 6, 2026. https://www.fda.gov/news-events/press-announcements/fda-clears-first-blood-test-used-diagnosing-alzheimers-disease