Soluble epoxide hydrolase deficiency rescues heart failure with preserved ejection fraction by targeting cytochrome...

Our prior clinical studies established a positive correlation between sEH activity and mortality in heart failure with preserved ejection fraction (HFpEF), the pathophysiological role of the sEH/EET axis in metabolic stress (obesity and metabolic syndrome) and mechanical stress (hypertension)-induced HFpEF remains unknown.

We elucidated the function and mechanism of sEH and EETs in 'two-hit' (high-fat diet and inhibition of constitutive nitric oxide synthase using Nω-nitrol-arginine methyl ester) HFpEF animal model. Langendorff system was applied to isolate cardiomyocytes from HFpEF mice. Recombinant adeno-associated virus type 9 was used to deliver cytochrome P450 2E1 (CYP2E1) to cardiac-specific knockout sEH HFpEF mice through the tail vein.

sEH activity and expression were upregulated, while EETs levels were reduced in the hearts and isolated cardiomyocytes from HFpEF mice or cardiomyocyte cell lines pretreated with palmitate acid and Nω-nitrol-arginine methyl ester. Desuccinylation, a posttranslational modification of sEH (K)¹⁹¹, maintained the activity of sEH in HFpEF. Genetic or pharmacological inhibition of the sEH restored the levels of EETs and ameliorated HFpEF phenotype with significantly improved diastolic dysfunction and cardiac remodeling. Mechanically, sEH inhibitors (sEHIs) targeted CYP2E1, a crucial CYP450 enzyme, to inhibit reactive oxygen species (ROS) and fatty acid uptake. Overexpressing CYP2E1 abolished the protective effects of sEH inhibition in vivo.

These findings confirmed sEH as a therapeutic target in metabolic stress and mechanical stress-induced HFpEF mice model via the cardioprotective effects of EETs, which were mediated partially by targeting CYP2E1, suggesting the development of therapeutic strategies for patients with HFpEF.