MAPT and Alzheimer disease: Exosomes have been found to contain both Aβ and tau, and their levels in exosomes have been associated with AD.[216] For instance, a study found that exosomal tau with seeding activity is released from AD synapses, and its seeding potential is associated with Aβ.[217] This suggests that exosomal tau may contribute to the spread of Tau pathology in AD, and its interaction with Aβ may play a role in this process.