CHAPTER 7: The Role of Extracellular Vesicles in the Neuronal System: Application of Extracellular Vesicles in Alzheimer's Disease, Parkinson's Disease, Multiple Sclerosis, and Dementia

Extracellular vesicles play a plethora of roles in the healthy central nervous system, ranging from neuronal firing and synaptic plasticity to myelin homeostasis and maintenance of blood–brain barrier integrity. However, extracellular vesicles may also take on pathological roles by spreading neurotoxic protein aggregates and propagating inflammation between the central nervous system and the periphery. Their ability to cross the blood–brain barrier presents an exciting opportunity for the development of peripherally sourced biomarkers for central nervous system diseases. Additionally, their abilities to target specific cells and evade the immune system highlight the prospect of extracellular vesicle therapy. The following chapter will explore the role of extracellular vesicles in the healthy central nervous system and in the context of Alzheimer's disease, Parkinson's disease, multiple sclerosis, and dementia. The potential use of extracellular vesicles as non-invasive biomarkers for these neurodegenerative pathologies will be detailed and their possible use as intrinsic therapeutics or vehicles for traditional therapeutics will be discussed. As the extracellular vesicle field expands, so will the ability to translate biomarker and therapy findings into clinical settings, bringing research efforts closer to improving treatment options for individuals with incurable neurodegenerative diseases.