APP and Alzheimer disease: In our recent study, we found that the liver weights of APP/PS-1 transgenic (Tg) mice, the animal model for AD, decreased significantly, and liver cell necrosis as well as lymphocyte infiltration increased obviously compared to wild type mice [36], which indicates that the liver plays important roles in the pathogenesis of AD through affecting on Aβ metabolism [32, 37, 38].