Instead, at this time-point the expression of glia fibrillary acidic protein (GFAP), an astrocyte biomarker (Yang and Wang, 2015), was significantly reduced in the dentate gyrus and CA3 regions, suggesting that an initial microglia activation was succeeded by a loss of function and reactivity of astrocytes, a process that may contribute to brain aging and to neurodegeneration in AD (Birch, 2014; De Strooper and Karran, 2016). This evidence concerns the gene GFAP and Alzheimer disease.