SIRT1 and Alzheimer disease: HT also improved mitochondrial function and prevented oxidative stress by activating the silent information regulator 1 (SIRT1)–AMP-activated protein kinase (AMPK) peroxisome proliferator-activated receptor gamma coactivator 1 (PGC1) axis in the brain of db/db mice, a model of type 2 diabetes [53], whose unregulated glucose metabolism is related to AD onset [54].