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The promising results obtained in the PARADIGM-HF trial prompted the approval of sacubitril/valsartan (SAC/VAL) as a first-in-class treatment for heart failure with reduced ejection fraction (HFrEF) patients. The effect of SAC/VAL treatment was also studied in patients with heart failure with preserved ejection fraction (HFpEF) and, although improvements in New York Heart Association (NYHA) class, HF hospitalizations, and cardiovascular deaths were observed, these results were not so promising. However, the demand for HFpEF therapies led to the approval of SAC/VAL as an alternative treatment, although further studies are needed. We aimed to elucidate the effects of a 9-week SAC/VAL treatment in cardiac function and metabolism using a preclinical model of HFpEF, the Zucker Fatty and Spontaneously Hypertensive (ZSF1) rats. We found that SAC/VAL significantly improved diastolic function parameters and modulated respiratory quotient during exercise. Ex-vivo studies showed that SAC/VAL treatment significantly decreased heart, liver, spleen, and visceral fat weights; cardiac hypertrophy and percentage of fibrosis; lipid infiltration in liver and circulating levels of cholesterol and sodium. Moreover, SAC/VAL reduced glycerophospholipids, cholesterol, and cholesteryl esters while increasing triglyceride levels in cardiac tissue. In conclusion, SAC/VAL treatment improved diastolic and hepatic function, respiratory metabolism, reduced hypercholesterolemia and cardiac fibrosis and hypertrophy, and was able to modulate cardiac metabolic profile. Our findings might provide further insight into the therapeutic benefits of SAC/VAL treatment in obese patients with HFpEF., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Sarcopenia is associated with reduced quality of life and premature mortality. The sex disparities in the processes underlying sarcopenia pathogenesis, which include mitochondrial dysfunction, are ill-understood and can be decisive for the optimization of sarcopenia-related interventions. To improve the knowledge regarding the sex differences in skeletal muscle aging, the gastrocnemius muscle of young and old female and male rats was analyzed with a focus on mitochondrial remodeling through the proteome profiling of mitochondria-enriched fractions. To the best of our knowledge, this is the first study analyzing sex differences in skeletal muscle mitochondrial proteome remodeling. Data demonstrated that age induced skeletal muscle atrophy and fibrosis in both sexes. In females, however, this adverse skeletal muscle remodeling was more accentuated than in males and might be attributed to an age-related reduction of 17beta-estradiol signaling through its estrogen receptor alpha located in mitochondria. The females-specific mitochondrial remodeling encompassed increased abundance of proteins involved in fatty acid oxidation, decreased abundance of the complexes subunits, and enhanced proneness to oxidative posttranslational modifications. This conceivable accretion of damaged mitochondria in old females might be ascribed to low levels of Parkin, a key mediator of mitophagy. Despite skeletal muscle atrophy and fibrosis, males maintained their testosterone levels throughout aging, as well as their androgen receptor content, and the age-induced mitochondrial remodeling was limited to increased abundance of pyruvate dehydrogenase E1 component subunit beta and electron transfer flavoprotein subunit beta. Herein, for the first time, it was demonstrated that age affects more severely the skeletal muscle mitochondrial proteome of females, reinforcing the necessity of sex-personalized approaches towards sarcopenia management, and the inevitability of the assessment of mitochondrion-related therapeutics., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Heart failure with preserved ejection fraction (HFpEF) is a syndrome characterized by impaired cardiovascular reserve in which therapeutic options are scarce. Our aim was to evaluate the inodilator levosimendan in the ZSF1 obese rat model of HFpEF. Twenty-week-old male Wistar-Kyoto (WKY), ZSF1 lean (ZSF1 Ln) and ZSF1 obese rats chronically treated for 6-weeks with either levosimendan (1 mg/kg/day, ZSF1 Ob + Levo) or vehicle (ZSF1 Ob + Veh) underwent peak-effort testing, pressure-volume (PV) haemodynamic evaluation and echocardiography (n = 7 each). Samples were collected for histology and western blotting. In obese rats, skinned and intact left ventricular (LV) cardiomyocytes underwent in vitro functional evaluation. Seven additional ZSF1 obese rats underwent PV evaluation to assess acute levosimendan effects (10 μg/kg + 0.1 μg/kg/min). ZSF1 Ob + Veh presented all hallmarks of HFpEF, namely effort intolerance, elevated end-diastolic pressures and reduced diastolic compliance as well as increased LV mass and left atrial area, cardiomyocyte hypertrophy and increased interstitial fibrosis. Levosimendan decreased systemic arterial pressures, raised cardiac index, and enhanced LV relaxation and diastolic compliance in both acute and chronic experiments. ZSF1 Ob + Levo showed pronounced attenuation of hypertrophy and interstitial fibrosis alongside increased effort tolerance (endured workload raised 38 %) and maximum O 2 consumption. Skinned cardiomyocytes from ZSF 1 Ob + Levo showed a downward shift in sarcomere length-passive tension relationship and intact cardiomyocytes showed decreased diastolic Ca 2+ levels and enhanced Ca 2+ sensitivity. On molecular grounds, levosimendan enhanced phosphorylation of phospholamban and mammalian target of rapamycin. The observed effects encourage future clinical trials with levosimendan in a broad population of HFpEF patients., Competing Interests: Declaration of competing interest None., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)