Significance: It has gradually been recognized that the vesicles secreted by cells are a major means by which cells communicate with each other. This recognition has stimulated interest in using vesicles to deliver therapeutic agents. The results presented here address several limitations to progress in the field by developing protocols to produce and isolate large numbers of extracellular vesicles (EVs) from stem-like cells found in the bone marrow. The isolated EVs were found to reduce the adverse effects of traumatic injury to the brain in mice.

Significance: This study demonstrated that intranasal (IN) administration of A1-exosomes alleviates multiple adverse changes that typically emerge after status epilepticus (SE), a medical crisis that presents a high propensity to evolve into chronic hippocampus dysfunction. Specifically, A1-exosome treatment after SE led to reduced neuron loss and inflammation, maintenance of normal neurogenesis, and preservation of cognitive and memory function. The results have significance for clinical application of A1-exosomes for curbing the evolution of SE-induced injury into chronic hippocampus dysfunction. The results also imply that IN administration of A1-exosomes is therapeutic for other neurological conditions that present with significant neuroinflammation.