“…[174] Many studies in the TBI animal model have reported that intravascular injection of stem cell-derived exosomes has been able to successfully suppress proinflammatory signaling, suppress expression of inflammatory cytokines, promote anti-inflammatory microglial phenotype, attenuate apoptosis, facilitate autophagy, attenuate brain swelling, increase vascular density, promote neurogenesis, and reduce reactive gliosis at the site of injury, which reduces lesion size and improve long-term functional recovery after injury. [175][176][177][178] Since stem cell-derived exosomes are also naturally permeable to BBB, biodegradable, and able to home to the inflamed brain region, [179] and can be engineered to carry molecules of interest, they are also an ideal platform for the development of nanotherapeutic for TBI. [174] The most common way to engineer an exosome is to manipulate its microRNA (miR) content.…”