Blood tests of brain function: Neuronal extracellular vesicles

Extracellular vesicles (EVs) are tiny (<1 µm) membrane-bound vesicles released by all tissues (including the brain) that cross the blood-brain barrier and facilitate cell-to-cell communication within and among tissues. They represent the body’s “Twitter system,” rapidly disseminating packets of information throughout the brain and body. Not unlike Twitter, EVs convey short messages through their cargos (e.g., RNAs, proteins, lipids, and metabolites), which direct the molecular activity of recipient cells in both health and disease. Extracellular vesicles serve as mediators of brain function and represent a reservoir for CNS-specific biomarkers that can be sequestered from plasma to guide diagnosis and treatment, representing a new frontier in the molecular study of psychiatric illness and in the development of biomarkers. The EV field has immense potential to revolutionize diagnostic approaches in psychiatry, facilitate precision treatment, predict response, and discover much-needed novel therapeutics.