In biopsied AD brains, biochemical data collectively suggest that there is likely enhanced fission, overexpression of dynamin-like protein 1 protein (DLP1) and down regulation of the optic atrophy protein 1 (OPA1) [104]; (iv) mitochondrial biogenesis is regulated by the Sirt1-PGC-1α axis and nuclear respiratory factor (NRF). Here, OPA1 is linked to Alzheimer disease.