Endothelial Epoxygenase, Kidney Injury, and Blood Pressure Regulation

Epidemiological and outcomes studies in patients, as well as studies in rodent models, reveal that renal ischemic kidney injury and unilateral obstructive uropathy brings on long-term consequences: hypertension and chronic kidney disease. Major pathophysiological contributors include impaired renal hemodynamics, endothelial dilator dysfunction, and endothelial cell inflammation. Because the renal microcirculation lacks efficient regenerative capacity, acute damage to the microcirculation can lead to long-term changes in renal hemodynamics that predispose patients to hypertension and chronic kidney disease. A class of arachidonic acid metabolites, epoxyeicosatrienoic acids (EETs) increase renal blood flow and improve endothelial cell function. Not known is the contribution of CYP2C epoxygenases, soluble epoxide hydrolase (sEH), and regioisomeric EETs to salt-sensitive hypertension and chronic kidney disease following obstructive uropathy and renal ischemic injury. We hypothesize that decreased endothelial EET levels result in endothelial dysfunction and impaired renal hemodynamics following renal ischemic injury or urinary tract obstruction. The immediate goals of this project are to determine the ability for endothelial EETs to improve endothelial- dependent afferent arteriolar dilation, to decrease endothelial inflammation, and to prevent salt-sensitive hypertension and chronic kidney disease following unilateral ureter obstruction (UUO) or ischemia/reperfusion (I/R) kidney injury. This project will utilize pharmacological as well as global and tissue-specific genetic manipulation of CYP2C, sEH, and EETs. We will obtain our immediate goals by completing three aims. Aim 1 will test the hypothesis that decreased EET levels or EET function contributes to the development of salt- sensitive hypertension and chronic kidney disease following UUO or I/R kidney injury. Aim 2 will test the hypothesis that increasing endothelial EET levels will improve renal microvascular endothelial function following UUO or I/R kidney injury to prevent salt-sensitive hypertension and chronic kidney disease. Aim 3 will test the hypothesis that pharmacological approaches to increase EET levels can prevent the long-term salt-sensitive hypertensive and chronic kidney injury following UUO or I/R kidney injury. Accordingly, our findings promise to advance the field forward by not only enhancing our understanding of the pathophysiological mechanisms whereby UUO or I/R kidney injury leads to chronic kidney disease but also leading to new therapeutic treatments.