INS and Alzheimer disease: Abnormalities involving almost all of these steps from glucose transportation abnormalities including insulin resistance, abnormal glucose transporter [26] and/or blood flow [27], to intracellular glucose metabolism disturbance including abnormalities in cytosolic processes (i.e., glycolysis and pentose phosphate pathway), in addition to abnormal mitochondria-dependent processes (TCA cycle and oxidative phosphorylation as discussed in details in the next section), were identified in AD brain, which all could contribute to glucose hypometabolism.