SIRT1 and brain ischemia: Upstream regulators of mitochondrial biogenesis, e.g., transcription factors such as SIRT1 (silent mating-type information regulation 2 homolog 1) and PGC1-α (peroxisome proliferator-activated receptor gamma coactivator-1 alpha) play key roles in the pathophysiology of brain ischemia (Chen et al., 2011).