Soluble epoxide hydrolase inhibition exerts beneficial anti-remodeling actions post-myocardial infarction.

BACKGROUND: A contributory role for soluble epoxide hydrolase (sEH) in cardiac remodeling post-myocardial infarction (MI) has been suggested; however effects of sEH inhibition following MI have not been evaluated. In this study, we examined in vivo post-MI anti-remodeling effects of a novel sEH inhibitor (GSK2188931B) in the rat, and evaluated its direct in vitro effects on hypertrophy, fibrosis and inflammation. METHODS AND
RESULTS: Post-MI administered GSK2188931B (80 mg/kg/d in chow) for 5 weeks improved left ventricular (LV) ejection fraction compared to vehicle-treated (Veh) rats (P<0.01; Sham 65 ± 2%, MI+Veh 30 ± 2%, MI+GSK 43 ± 2%) without affecting systolic blood pressure. Percentage area of LV tissue sections stained positive for picrosirius red (PS) and collagen I (CI) were elevated in LV non-infarct zone (P<0.05; NIZ; PS: Sham 1.46 ± 0.13%, MI+Veh 2.14 ± 0.22%, MI+GSK 1.28 ± 0.14%; CI: Sham 2.57 ± 0.17%, MI+Veh 5.06 ± 0.58%, MI+GSK 2.97 ± 0.34%) and peri-infarct zone (P<0.001; PIZ; PS: Sham 1.46 ± 0.13%, MI+Veh 9.06 ± 0.48%, MI+GSK 6.31 ± 0.63%; CI: Sham 2.57±0.17%, MI+Veh 10.51 ± 0.64%, MI+GSK 7.77 ± 0.57%); GSK2188931B attenuated this increase (P<0.05). GSK2188931B reduced macrophage infiltration into the PIZ (P<0.05). GSK2188931B reduced AngII- and TNFα-stimulated myocyte hypertrophy, AngII- and TGFβ-stimulated cardiac fibroblast collagen synthesis, including markers of gene expression ANP, β-MHC, CTGF and CI (P<0.05). GSK2188931B reduced TNFα gene expression in lipopolysaccharide (LPS)-stimulated monocytes (P<0.05).
CONCLUSION: sEH inhibition exerts beneficial effects on cardiac function and ventricular remodeling post-MI, and direct effects on fibrosis and hypertrophy in cardiac cells. These findings suggest that sEH is an important contributor to the pathological remodeling following MI, and may be a useful target for therapeutic blockade in this setting.