AQP4 and Alzheimer disease: Molecular analyses of the parahippocampal gyrus and endothelial cell-enriched isolates from AD patients, both with and without comorbid diabetes mellitus, have revealed that antidiabetic treatments May normalize the expression of key vascular And metabolic Markers, such as mRNA levels of neural cell adhesion molecule 1 (NCAM1) and aquaporin-4.