MAPT and Alzheimer disease: Earlier, we have reported that treatment with SkQ1 starting from the predementia phase of AD (consistent with the definition of progressive, amnestic mild cognitive impairment in humans) prevents the neuronal loss and synaptic damage, enhances neurotrophic supply, and decreases Aβ1–42 peptide levels and tau hyperphosphorylation in the hippocampus of OXYS rats, as well as improving the structural and functional state of mitochondria, thus improving the learning ability and memory [12,13,14,15].