Coronary
reactive hyperemia (CRH) is a physiological response to ischemic insult that prevents the potential harm associated with an interruption of blood supply. The relationship between the pharmacologic inhibition of soluble
epoxide hydrolase (sEH) and CRH response to a brief
ischemia is not known. sEH is involved in the main catabolic pathway of epoxyeicosatrienoic
acids (EETs), which are converted into dihydroxyeicosatrienoic
acids (DHETs). EETs protect against
ischemia/reperfusion injury and have numerous beneficial physiological effects. We hypothesized that inhibition of sEH by
t-AUCB enhances CRH in isolated mouse hearts through changing the
oxylipin profiles, including an increase in EETs/DHETs ratio. Compared to controls,
t-AUCB-treated mice had increased CRH, including repayment volume (RV), repayment duration, and repayment/debt ratio (p < 0.05). Treatment with
t-AUCB significantly changed
oxylipin profiles, including an increase in EET/DHET ratio, increase in EpOME/DiHOME ratio, increase in the levels of HODEs, decrease in the levels of mid-chain HETEs, and decrease in
prostanoids (p < 0.05). Treatment with
MS-PPOH (CYP epoxygenase inhibitor) reduced CRH, including RV (p < 0.05). Involvement of PPARγ in the modulation of CRH was demonstrated using a PPARγ-antagonist (
T0070907) and a PPARγ-agonist (
rosiglitazone).
T0070907 reduced CRH (p < 0.05), whereas
rosiglitazone enhanced CRH (p < 0.05) in isolated mouse hearts compared to the non-treated. These data demonstrate that sEH inhibition enhances, whereas CYP epoxygenases-inhibition attenuates CRH, PPARγ mediate CRH downstream of the CYP epoxygenases-EET pathway, and the changes in
oxylipin profiles associated with sEH-inhibition collectively contributed to the enhanced CRH.