Abstract 13631: Therapeutic Inhibition of Mitochondrial Reactive Oxygen Species With Mito-tempo Reduces Diabetic Cardiomyopathy

Abstract

Introduction: The mitochondria are important sources of reactive oxygen species (ROS) in the heart. Mitochondrial ROS production and subsequent oxidative damage have been implicated in the pathogenesis of diabetic cardiomyopathy. We hypothesized that therapeutic strategies specifically targeting mitochondrial ROS may have benefit in diabetic cardiomyopathy. Hypothesis: We hypothesized that therapeutic inhibition of mitochondrial ROS with mito-TEMPO reduces diabetic cardiomyopathy. Methods: The mitochondria-targeted antioxidant mito-TEMPO was administrated after diabetes onset in a mouse model of streptozotocin (STZ)-induced type-1 diabetes and type-2 diabetic db/db mice. Cardiac adverse changes were analyzed and myocardial function assessed. Cultured adult cardiomyocytes were stimulated with high glucose, and single mitochondrial superoxide generation and cell death were measured. Results: Incubation with high glucose increased mitochondria superoxide generation in cultured adult cardiomyocytes, which was prevented by mito-TEMPO. Co-incubation with mito-TEMPO also abrogated high glucose-induced cell death. Mitochondrial ROS generation, and intracellular ROS formation and oxidative damage were induced in both type-1 and type-2 diabetic mouse hearts. Daily injection of mito-TEMPO for 30 days inhibited mitochondrial ROS generation, prevented intracellular ROS formation and oxidative damage, decreased apoptosis and reduced myocardial hypertrophy in diabetic hearts without change of blood glucose, leading to improvement of myocardial function in both type-1 and type-2 diabetic mice. Mechanistic study revealed that the protective effects of mito-TMEPO were associated with down-regulation of ERK1/2 phosphorylation in diabetic hearts and high glucose-stimulated cardiomyocytes. Conclusions: Therapeutic inhibition of mitochondrial ROS by mitochondria-targeted antioxidant mito-TEMPO reduced adverse cardiac changes and mitigated myocardial dysfunction in both type-1 and type-2 diabetic mice. Thus, mitochondria-targeted antioxidants may be an effective therapy for diabetic cardiac complications.