APP and Alzheimer disease: In support of this theory, Sun et al. [100] reported that FMT from WT-mice to the APP/PS1 mice model of AD resulted in the alleviated brain deposition of Aβ as well as levels of neurotoxic Aβ40 and Aβ42, tau protein phosphorylation, synaptic dysfunction, neuroinflammation and cognitive deficits, accompanied with restored alterations in gut microbiota and faecal SCFA levels.