Using CD68 staining as a marker for microglia/macrophage activation in the brain, we observed significantly increased CD68 immunoreactivity in the amygdala of the early AD mouse brain that was not significantly reduced by EV treatment (Fig. 6a; P < 0.05 for AD vs WT groups); however, no significant differences among experimental groups were observed for CD68 in the mPFC region of the brain at that same time (Fig. 6b). Here, CD68 is linked to Alzheimer disease.