Effects of a High Glycemic Diet and Soluble Epoxide Hydrolase Inhibitor on Hippocampal Microvascular Function, and Multigenomic Modifications

OBJECTIVES: Diet is a modifiable risk factor for cardiovascular disease (CVD) and dementia, yet relatively little is known about the effect of a high glycemic diet (HGD) on the brain microvasculature. The objective of our study was to determine the multigenomic effects of a HGD on hippocampal microvessels, and to determine if a soluble epoxide hydrolase (sEH) inhibitor (sEHI), known to be vasculoprotective and anti-inflammatory, modulates these effects. METHODS: Wild type male and female mice were fed a low glycemic diet (LGD, 12% sucrose/weight) or a HGD (34% sucrose/weight) with/without the sEHI, trans-4-[4-(3-adamantan-1-yl-ureido)-cyclohexyloxy]-benzoic acid (t-AUCB), for 12 wks. Brain hippocampal microvascular gene expression was assessed by microarray and data analyzed using a multiomic approach for differential expression of protein and non-protein coding genes, gene networks, functional pathways, and transcription factors. RESULTS: Global hippocampal microvascular gene expression was fundamentally different for mice fed the HGD vs the LGD. The HGD modulated expression of genes involved in cell signaling, neurodegeneration, metabolism, and cell adhesion/inflammation/oxidation effects reversible by t-AUCB and hence sEH inhibitor correlated with protection against Alzheimer's dementia. However, in female, HGD had very minor genomic modifications, while sEHI presented significant effect in female mice on LGD. CONCLUSIONS: Ours is the first study to demonstrate that high dietary glycemia contributes to brain hippocampal microvascular inflammation, through sEH, effects that were sex-dependant. FUNDING SOURCES: This work was supported by an award from the Richard A. and Nora Eccles Foundation (A20-0111), the Richard A. and Nora Eccles Harrison Endowed Chair in Diabetes Research (J.C.R.), and the Frances Lazda Endowed Chair in Women's Cardiovascular Medicine (A.C.V).