The relationship between soluble epoxide hydrolase (sEH) and coronary reactive hyperemia (CRH) response to a brief ischemic insult is not known. Epoxyeicosatrienoic acids (EETs) exert cardioprotective effects in ischemia/reperfusion injury. sEH converts EETs into dihydroxyeicosatrienoic-acids (DHETs). Therefore, we hypothesized that knocking out sEH enhances CRH through modulation of oxylipin profiles including an increase in EETs/DHETs ratio. Compared to sEH+/+, sEH-/- mice showed enhanced CRH, including greater repayment volume (RV; 28% higher, p<0.001) and repayment/debt ratio (32% higher, p<0.001). Oxylipins from the heart perfusates were analyzed by LC-MS/MS. The 14,15-EET/14,15-DHET ratio was 3.7 fold higher at baseline (p<0.001) and 5.6 fold higher post-ischemia (p<0.001) in sEH-/- compared to sEH+/+ mice. Likewise, the baseline 9,10- and 12,13-EpOME/DiHOME ratios were 3.2 (p<0.01) and 3.7 (p<0.001) fold higher, respectively in sEH-/- compared to sEH+/+ mice. 13-HODE was also significantly increased at baseline by 71% (p<0.01) in sEH-/- vs. sEH+/+ mice. Levels of 5-, 11-, 12-, and 15-HETEs were not significantly different between the two strains (p>0.05), but were decreased post-ischemia in both groups (p=0.02, p=0.04, p=0.05, p=0.03 respectively). Modulation of CRH by PPARγ was demonstrated using a PPARγ-antagonist (T0070907), which reduced repayment volume by 25% in sEH+/+ (p<0.001) and 33% in sEH-/- mice (p<0.01), and a PPARγ-agonist (rosiglitazone), which increased repayment volume by 37% in both sEH+/+ (p=0.04) and sEH-/- mice (p=0.04). L-NAME attenuated CRH in both sEH-/- and sEH+/+. These data demonstrate that genetic deletion of sEH resulted in an altered oxylipin profile which may have led to an enhanced CRH response.
- Coronary reactive hyperemia
- epoxyeicosatrienoic acids
- soluble epoxide hydrolase
- isolated perfused heart
- Copyright © 2016, American Journal of Physiology-Regulatory, Integrative and Comparative Physiology