ABC | Volume 111, Nº3, September 2018

Original Article Pinotti et al Fasting/refeeding cycles and myocardial remodeling Arq Bras Cardiol. 2018; 111(3):400-409 The beneficial effects of the intermittent fasting result from at least two mechanisms: the oxidative stress and the stress resistance hypothesis. 39 According to literature, during the intermittent fasting, there are fewer free radicals produced in the mitochondria of cells and, therefore, less oxidative damage to the cells. 39 Another hypothesis is the resistance to stress that is associated with increased resistance of cells in many different tissues to injury induced by oxidative, genotoxic and metabolic insults. The conservation of stress resistance responses to intermittent fasting across a range of species provides strong evidence that this mechanism contributes to the lifespan-extending action of dietary restriction. 39 It is worth noting that according to studies in rodents and humans, intermittent food restriction is capable of promoting weight loss and/or favorably influence an array of cardiometabolic health indices, with equal or greater efficacy than conventional continuous energy restriction approaches, such as food restriction. 29 Fasting/refeeding cycles increase cardiac tolerance to ischemic injury and can affect the development of cardiovascular disease, preventing postinfarct cardiac remodeling, and impending chronic heart failure. 29 Comparing the two dietary approaches, studies show that caloric restriction may exert its beneficial effects primarily by reducing oxidative stress, whereas RF may act primarily by a stress resistance mechanism, 40 which can have a cardioprotective effect. Study limitations The study did not investigate the activity and protein expression of Ca 2+ handling regulatory proteins known to affect myocardial contraction and relaxation. In addition, the current study did not evaluate the involvement of anti‑inflammatory cytokines, free-radical production and cellular stress response, which could help and consolidate the beneficial effects of intermittent fasting. Conclusion We demonstrated that fasting/refeeding promotes cardiac beneficial effects and attenuates myocardial injury caused by CR in SHR rats, contributing to the reduction of cardiovascular risk profile and morphological injuries. Furthermore, RF promotes mild improvement in the Ca 2+ handling and β -adrenergic system. Author contributions Conception and design of the research: Pinotti MF, Cicogna AC, Leopoldo AS; Acquisition of data: Pinotti MF, Matias AM, SugizakiMM,NascimentoAF, PaiMD, LeopoldoAPL; Analysis and interpretation of the data: Pinotti MF, Sugizaki MM, Nascimento AF, Pai MD, Leopoldo APL; Statistical analysis: Sugizaki MM, Nascimento AF, Pai MD, Leopoldo APL; Obtaining financing: Cicogna AC; Writing of the manuscript: Pinotti MF, Matias AM, Cicogna AC, Leopoldo AS; Critical revision of the manuscript for intellectual content: Matias AM, Pai MD, Leopoldo APL, Cicogna AC, Leopoldo AS. Potential Conflict of Interest No potential conflict of interest relevant to this article was reported. Sources of Funding This study was funded by FAPESP number 04/04654-6. Study Association This study is not associatedwith any thesis or dissertationwork. 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