Abstract W P363: Mechanism of Protection by Soluble Epoxide Hydrolase Inhibition in Type 2 Diabetic Stroke
Hyperglycemia worsens stroke, yet rigorous glycemic control does not improve neurologic outcome. An alternative is to target downstream molecular mediators triggered by hyperglycemia. Soluble epoxide hydrolase (sEH) is a potential mediator of ischemic injury via its metabolism of neuroprotective epoxyeicosatrienoic acids (EETs). We previously demonstrated that sEH mRNA is overexpressed in type 1 diabetic (T1D) mice, and specific sEH blockade protects the brain from the deleterious effect of T1D on stroke. We tested the hypothesis that type 2 diabetes (T2D) exacerbates injury following middle cerebral artery occlusion (MCAO) in part by up-regulating expression of EPHX2 (gene encoding for sEH) and decreasing brain concentrations of neuroprotective EETs. T2D was produced by combined high-fat diet, nicotinamide and streptozotocin in male C57BL/6J mice. T2D and control mice were treated with vehicle or the sEH inhibitor trans-4-[4-(3-Adamantan-1-yl-ureido) -cyclohexyloxy]-benzoic acid (t-AUCB; 1mg/kg, i.p., 7 days), then subjected to 60-min MCAO. Compared to normal chow-fed mice, high fat diet-fed mice exhibited a 1.7 fold upregulation of EPHX2 mRNA in brain (p<0.05, n=7). T2D mice had increased blood glucose levels compared to control mice before, during and after MCAO (p<0.001, n=4-5). Relative laser-Doppler perfusion of the MCA territory after reperfusion was decreased in T2D mice compared to controls (p<0.05, n= 4-5). Vehicle-treated T2D mice sustained larger cortical infarcts than vehicle-treated control mice (p<0.05, n=5-7). t-AUCB decreased fasting glucose levels at baseline and throughout ischemia (p<0.001, n=4-5) and improved cortical perfusion after MCAO (p<0.001, n=4-5) in T2D mice. In line with these improvements, t-AUCB significantly reduced infarct size in T2D mice (p<0.05 vs. T2D vehicle, n= 5-7). We conclude that increasing EETs bioavailability via sEH inhibition improves stroke outcome in T2D in part by improving glycemic status and improving post-ischemic reperfusion in the ischemic territory.
Author Disclosures: K.L. Zuloaga: Research Grant; Significant; F32NS082017-01. S.M. Krasnow: None. W. Zhang: None. R.E. Shangraw: None. D.L. Marks: Research Grant; Significant; R01DK70333. N.J. Alkayed: Research Grant; Significant; R01NS044313, R01NS070837.
- © 2014 by American Heart Association, Inc.