Reduced coronary reactive hyperemia in mice was reversed by the soluble epoxide hydrolase inhibitor (t-AUCB): Role of adenosine A 2A receptor and plasma oxylipins.

Coronary reactive hyperemia (CRH) protects the heart against ischemia. Adenosine A2A AR-deficient (A2A AR-/- ) mice have increased expression of soluble epoxide hydrolase (sEH); the enzyme responsible for breaking down the cardioprotective epoxyeicosatrienoic acids (EETs) to dihydroxyeicosatrienoic acids (DHETs). sEH-inhibition enhances CRH, increases EETs, and modulates oxylipin profiles. We investigated the changes of oxylipins and their impact on CRH in A2A AR-/- and wild type (WT) mice. We hypothesized that the attenuated CRH in A2A AR-/- mice is mediated by changes in oxylipin profiles, and that it can be reversed by either sEH- or ω-hydroxylases-inhibition. Compared to WT mice, A2A AR-/- mice had attenuated CRH and changed oxylipin profiles, which were consistent between plasma and heart perfusate samples, including decreased EET/DHET ratios, and increased hydroxyeicosatetraenoic acids (HETEs). Plasma oxylipns in A2A AR-/- mice indicated an increased proinflammatory state including increased ω-terminal HETEs, decreased epoxyoctadecaenoic/dihydroxyoctadecaenoic acids (EpOMEs/DiHOMEs) ratios, increased 9-hydroxyoctadecadienoic acid, and increased prostanoids. Inhibition of either sEH or ω-hydroxylases reversed the reduced CRH in A2A AR-/- mice. In WT and sEH-/- mice, blocking A2A AR decreased CRH. These data demonstrate that A2A AR-deletion was associated with changes in oxylipin profiles, which may contribute to the attenuated CRH. Also, inhibition of sEH and ω-hydroxylases reversed the reduction in CRH.