In a guinea pig model of heart failure, in vivo treatment with the mitochondrially targeted antioxidant MitoTEMPO prevented and reversed HF and eliminated sudden cardiac death.
Does in vivo reduction of mitochondrial ROS with MitoTEMPO prevent sudden cardiac death and reverse remodeling in a guinea pig model of nonischemic heart failure?
Targeted reduction of mitochondrial reactive oxygen species with MitoTEMPO prevents sudden cardiac death and reverses proteome remodeling in a preclinical model of nonischemic heart failure, highlighting a potential new therapeutic target.
Rationale: Despite increasing prevalence and incidence of heart failure (HF), therapeutic options remain limited. In early stages of HF, sudden cardiac death (SCD) from ventricular arrhythmias claims many lives. Reactive oxygen species (ROS) have been implicated in both arrhythmias and contractile dysfunction. However, little is known about how ROS in specific subcellular compartments contribute to HF or SCD pathophysiology. The role of ROS in chronic proteome remodeling has not been explored. Objective: We will test the hypothesis that elevated mitochondrial ROS (mROS) is a principal source of oxidative stress in HF and in vivo reduction of mROS mitigates SCD. Methods and Results: Using a unique guinea pig model of nonischemic HF that recapitulates important features of human HF, including prolonged QT interval and high incidence of spontaneous arrhythmic SCD, compartment-specific ROS sensors revealed increased mROS in resting and contracting left ventricular myocytes in failing hearts. Importantly, the mitochondrially targeted antioxidant (MitoTEMPO) normalized global cellular ROS. Further, in vivo MitoTEMPO treatment of HF animals prevented and reversed HF, eliminated SCD by decreasing dispersion of repolarization and ventricular arrhythmias, suppressed chronic HF-induced remodeling of the expression proteome, and prevented specific phosphoproteome alterations. Pathway analysis of mROS-sensitive networks indicated that increased mROS in HF disrupts the normal coupling between cytosolic signals and nuclear gene programs driving mitochondrial function, antioxidant enzymes, Ca 2+ handling, and action potential repolarization, suggesting new targets for therapeutic intervention. Conclusions: mROS drive both acute emergent events, such as electrical instability responsible for SCD, and those that mediate chronic HF remodeling, characterized by suppression or altered phosphorylation of metabolic, antioxidant, and ion transport protein networks. In vivo reduction of mROS prevents and reverses electrical instability, SCD, and HF. Our findings support the feasibility of targeting the mitochondria as a potential new therapy for HF and SCD while identifying new mROS-sensitive protein modifications.
Dey et al. (2018) studied Heart failure and sudden cardiac death. MitoTEMPO was evaluated on Sudden cardiac death, ventricular arrhythmias, and chronic HF-induced remodeling. In a guinea pig model of heart failure, in vivo treatment with the mitochondrially targeted antioxidant MitoTEMPO prevented and reversed HF and eliminated sudden cardiac death.
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