To lower the impact of different cellular number in each section, the percentages of ACE2+ cell (the percentage of the number of ACE2+ non-vascular cells with the number of non-vascular cell nucleus) within each brain region were further summarized, indicating reduced expression of ACE2 in basal nucleus, hippocampus and entorhinal cortex, middle frontal gyrus, and visual cortex under AD pathology (Figure 3C). This evidence concerns the gene ACE2 and Alzheimer disease.