In this study, we utilized LA–ICP–MS and SN–ICP–MS to investigate changes in transition metal levels in the HPC and retina of post-mortem human donors with AD history and post-mortem subjects without AD history, as well as age-related changes in the HPC, cortex, and retina of APP/PS1 and WT mice models aged 9 and 18 months, respectively. The gene discussed is APP; the disease is Alzheimer disease.