RESUMEN
PURPOSE: Alzheimer's disease (AD) and vascular dementia shared similar symptoms, the aim of the present study was to identify potential differences in the mechanisms underlying the two diseases. MATERIALS AND METHODS: The data set including AD, vascular dementia, and control samples was carried out gene differential expression analysis, weighted gene co-expression network analysis, functional enrichment, protein-protein interaction network construction, and least absolute shrinkage and selection operator analysis to reveal the differences in the mechanisms underlying the two diseases and potential diagnostic gene signature. RESULTS: We identified the gene modules related to AD or vascular dementia. Enrichment analysis of module genes and construction of a protein-protein interaction network suggested that the "brown" module may be involved in a chemokine pathway, the "blue" module may be involved in cortisol synthesis and secretion, and the "turquoise" module may be involved in cholinergic synapse transmission. The hub gene-based signature index may be a biomarker of AD and vascular dementia and may even differentiate the two diseases from each other with high area under curve. CONCLUSION: Our results identified not only core pathways involved in both AD and vascular disease, but also their potentially specific pathways. We proposed the hub gene-based signature index may be useful for diagnosing AD and vascular dementia.