Controlled hypertension induces cerebrovascular and gene alterations in Cyp1a1-Ren2 transgenic rats

Hypertension is a major risk factor for small vessel disease and dementia, but the pathogenic mechanisms are not fully known. This study aimed to assess cerebrovascular alterations in response to different durations (4 or 6 months) of controlled hypertension in an inducible transgenic rat model of hypertension (Cyp1a1-Ren2) as compared with normotensive litter mate controls. After 6 months of hypertension as compared with controls, a significant reduction in vascular width was paralleled by an increase in the protein levels of claudin-5, an endothelial tight junction protein. Notably, vascular alterations were associated with increased microglia, and these changes were preceded by increased eNOS expression. Investigation of global gene expression by microarray analysis indicated alterations in predominantly growth factor related genes. Herein, we show that modest, sustained levels of hypertension are sufficient to cause cerebrovascular alterations accompanied by endothelial and inflammatory changes. These changes are paralleled by alterations in growth factor expression suggestive of a mechanistic role.