AIF1 and Alzheimer disease: In vehicle-treated APP/PS1 mice, the percentage of the hippocampal CA1 area covered by Iba1 positive microglia was increased threefold compared to WT littermates (AD vehicle: 4.73 ± 0.73%, WT vehicle: 1.48 ± 0.17%), reflecting growth and/or proliferation of microglial cells (Figure 4C, left).