Potential of exosomes for targeted therapy in neuroinfectious disease management: crossing the blood-brain barrier

Neuroinfectious diseases such as meningitis, encephalitis, and myelitis continue to be a significant health issue especially in low- and middle-income nations where the timely identification and successful treatment are mostly not yet available. There is also the complicating factor of the restrictive nature of the blood-brain barrier (BBB) which greatly limits the passage of antimicrobial and anti-inflammatory agents through into the central nervous system. Exosomes which are nano-sized extracellular vesicles released by a vast variety of cells have been proposed as a promising solution to overcome this barrier because of their natural biocompatibility, low immunogenicity and capacity to enter the BBB by receptor-mediated, adsorptive-mediated and carrier-mediated processes. This review critically discusses the structural and functional dynamics of the BBB in infection, the recent discoveries in the exosome trafficking pathways, and the diagnostic and therapeutic role of exosomes in infection, including infections related to HIV-associated neurocognitive disorders, tuberculous meningitis, cryptococcal meningitis, neurotoxoplasmosis. Special consideration will be given to engineered exosomes and how they could be used to improve targeted delivery of drugs, decrease systemic toxicity and offer minimally invasive biomarkers platforms to detect disease earlier. He/she points possible solutions to CNS infections by combining mechanistic understanding with newly acquired pre-clinical and clinical results, this review emphasizes the increasing promise of exosome-based nanomedicine as a transformational technology.