MAPT and Alzheimer disease: Proteins reflecting key events of the neurodegenerative process have been isolated in exosomes extracted from CSF and blood by using proteomic analysis [244,245,246]; in particular, p-tau was isolated in CSF exosomes from patients with mild AD (Braak stage 3) [247], and increased levels of exosomes-associated tau and Aβ were found in AD patients compared to controls [248].