Based on evidence from earlier studies that peripheral blood levels of glutamate are positively correlated with levels of glutamate in the CSF55 and studies that reported lower levels of glutamate in patients with AD compared with controls in both blood56 and brain tissues,36,57,58,59 we can infer that lower levels of ALT or AST may affect glutamate levels in AD. Here, GPT is linked to Alzheimer disease.