The decreases of BDNF in the brain (Iulita et al., 2017) and serum are involved in the pathogenesis of AD (Curto et al., 2017), while intrahippocampal BDNF administration in rats shows protective role in against neuronal loss by suppressing the activation of microglia and astrocytes (Bovolenta et al., 2010). Here, BDNF is linked to Alzheimer disease.