APP and Alzheimer disease: The GIP analog D-Ala2-GIP showed neuroprotective effects in the APP/PS1 mouse model of AD by protecting memory formation, synaptic plasticity, reducing the amyloid plaque load and the chronic inflammation response in the brain, reducing oxidative stress, and normalizing neurogenesis in the dentate gyrus (Duffy and Holscher, 2013; Faivre and Holscher, 2013a,b).