Mitophagy-dependent cardioprotection of resistance training on heart failure.

Resistance exercise is an indispensable mode of exercise rehabilitation for heart failure. Here we elucidate the cardiac effects of resistance training alone or combined with different aerobic trainings on heart failure and explore the critical regulation of mitophagy. The chronic heart failure model was constructed by transverse aortic constriction surgery, followed by 8 wk of resistance training (RT), moderate-intensity continuous training combined with resistance training (MRT), and high-intensity interval training combined with resistance training (HRT), and subsequently analyzed the changes of maximum load, cardiac structure and function, and myocardial mitophagic activity. The role and signaling of mitophagy in exercise protection of heart failure were investigated by knockdown of Hif1α and Parkin genes in primary neonatal cardiomyocytes. RT and especially MRT improved maximum load (P < 0.0001), myocardial morphology and fibrosis (P < 0.0001), reduced left ventricular diameter and enhanced left ventricular systolic function (P < 0.01), and enhanced myocardial mitophagic activity and HIF1α expression (P < 0.05) in heart failure mice. However, HRT had no obvious protective effect on ventricular diameter and function or mitophagy. The abilities of exercise stimulation to regulate reactive oxygen species, adenosine triphosphate, and brain natriuretic peptide were impaired after knockdown of Hif1α and Parkin genes inhibited mitophagy in failing cardiomyocytes (P < 0.05). Different exercise modalities provide discrepant cardiovascular effects on heart failure, and MRT exhibits optimal protection. The HIF1α-Parkin-mitophagy pathway is involved in the protection and regulation of exercise on heart failure.NEW & NOTEWORTHY Impaired myocardial mitophagy is implicated in the pathogenesis of heart failure. Resistance training alone or combined with different aerobic trainings provide discrepant cardiovascular effects on heart failure, and the cardioprotective function depends on HIF1α-Parkin-mitophagy pathway.

Exercise training improves cardiac function and regulates myocardial mitophagy differently in ischaemic and pressure-overload heart failure mice.

NEW FINDINGS: What is the central question of this study? What are the cardioprotective effects of different aerobic exercises on chronic heart failure with different aetiologies, and is mitophagy involved? What is the main finding and its importance? Moderate-intensity continuous training may be the 'optimum' modality for improving cardiac structure and function in ischaemic heart failure, while both moderate-intensity continuous training and high-intensity interval training were suitable for pressure-overload heart failure. Various mitophagy pathways, especially parkin-dependent pathways, participated in the protective effects of exercise on heart failure. ABSTRACT: The cardioprotective effects of different aerobic exercises on chronic heart failure with different aetiologies and whether mitophagy is involved remain elusive. In the current research, left anterior descending ligation and transverse aortic constriction surgeries were used to establish mouse models of heart failure, followed by 8 weeks of moderate-intensity continuous training (MICT) and high-intensity interval training (HIIT). The results showed that for ischaemic heart failure MICT significantly improved ejection fraction (P < 0.05) and fractional shortening (P < 0.05), mitigated left ventricular end-systolic dimension (P < 0.01), decreased brain natriuretic peptide (P < 0.0001) and mitigated fibrosis (P < 0.0001), while HIIT only decreased brain natriuretic peptide (P < 0.0001) and fibrosis (P < 0.0001). For pressure-overload heart failure, both MICT and HIIT significantly increased ejection fraction (P < 0.0001) and fractional shortening (MICT: P < 0.001, HIIT: P < 0.0001), and reduced left ventricular end-diastolic and end-systolic dimensions, brain natriuretic peptide (P < 0.0001), and fibrosis (MICT: P < 0.01, HIIT: P < 0.0001); HIIT was even better in reducing brain natriuretic peptide. Myocardial autophagy and mitophagy were compromised in heart failure, and the exercises improved myocardial autophagic flux and mitophagy inconsistently in heart failure with different aetiologies. Significant correlations were found between multiple mitophagy pathways and the cardioprotection of the exercises. Collectively, MICT may be the 'optimum' modality for ischaemic heart failure, while both MICT and HIIT (especially HIIT) were suitable for pressure-overload heart failure. Exercises differently improved myocardial autophagy/mitophagy, and multiple mitophagy-related pathways were closely implicated in cardioprotection of exercises for chronic heart failure.