CAT and Alzheimer disease: To overcome this problem, recently we and other research groups found that mitochondria-targeted catalase (MCAT) has a beneficial role in both transgenic AD model mice and wild-type mice through multiple mechanisms including reduction of ROS and oxidative damage, as well as toxic Aβ42 production and deposits in the brain [61, 62], further indicating that mitochondria and oxidative stress play an important role in AD and normal aging.