Abstract P503: Aldehyde Dehydrogenase 2 Activator 1 Potentiates The Effects Of Empagliflozin, A Sodium-glucose Cotransporter 2 Inhibitor, In Diabetes-mediated Heart Failure With Preserved Ejection Fraction

Abstract

4-hydroxy-2-nonenal (4HNE), a cellular reactive aldehyde which is significantly increased in diabetic hearts due to decrease in the activity of its metabolizing enzyme, aldehyde dehydrogenase (ALDH)2, contributes to diabetes mellitus (DM)-mediated cardiotoxicity. Therefore, we hypothesize that lowering 4HNE ameliorates heart failure with preserved ejection fraction (HFpEF) in DM. To ameliorate DM mediated HFpEF, we will lower diabetes-mediated oxidative stress-induced 4HNE accumulation as well as augment 4HNE detoxification by activating ALDH2, via pharmacological agents. We induced type-2 DM by feeding high-fat diet (HFD) in ALDH2*2 mutant mice which have intrinsically low ALDH2 activity and thus having increased cardiac 4HNE levels. After 4 months of DM, the mice exhibited features of HFpEF and we treated the diabetic ALDH2*2 mice with vehicle (Veh), empagliflozin (EMP) (3mg/kg/d), a sodium-glucose cotransporter (SGLT) 2 inhibitor to reduce hyperglycemia and Alda-1 (10mg/kg/d), an ALDH2 activator to enhance ALDH2 activity as well as combination of EMP + Alda-1 (E + A), via subcutaneous osmatic pumps. After treating for 2 months, cardiac function was assessed by conscious echocardiography before and after exercise stress. EMP + Alda-1 improved running distance (RD, 231 ± 53 m), ejection fraction after running (EF, 69 ± 5 %), and decreased left atrial area (LA, 3.0 ± 0.2 mm 2 ), cardiomyocyte cross-section area (CA, 251 ± 32 μm 2 ) and myocardial fibrotic area (FA 1.0 ± 0.3 %) in ALDH2*2 mice with diabetic HFpEF compared to EMP (RD 142 ± 53 m; EF 62 ± 5 %; LA 3.5 ± 0.3 mm 2 ; CA 303 ± 55 μm 2 ; and FA 3.2 ± 1.8 %), Alda-1 (RD 183 ± 73 m; EF 68 ± 3 %; LA 3.2 ± 0.2 mm 2 ; CA 288 ± 34 μm 2 ; and FA 2.5 ± 1.2 %) and Veh (RD 52 ± 66 m; EF 55 ± 5.0 %; LA 4.7 ± 0.4 mm 2 ; CA 448 ± 65 μm 2 ; and FA 11 ± 3.5 %). This improvement was exerted by decreasing 4HNE levels as well as attenuating 4HNE-mediated decrease in cardiac liver kinase B1 (LKB1)-AMP-activated protein kinase (AMPK) pathway. In conclusion, our data implicate that ALDH2 activation along with the treatment of hypoglycemic agents may be important strategy to alleviate diabetic HFpEF.