Along the same way, it was observed that a mouse model of Alzheimer disease, the APP/PS1 transgenic mice, without gut microbiota showed less beta-amyloid plaque formation and its colonization with gut microbiota coming from APP/PS1 transgenic mice is worst in term of beta amyloid plaque formation compared to its colonization with a gut microbiota coming from healthy mice [135]. Here, APP is linked to Alzheimer disease.