The heart must consume a significant amount of energy to sustain its contractile activity. Although the fuel demands are huge, the stock remains very low. Thus, in order to supply its daily needs, the heart must have amazing adaptive abilities, which are dependent on dioxygen availability. However, in myriad cardiovascular diseases, “fuel” depletion and hypoxia are common features, leading cardiomyocytes to favor low-dioxygen-consuming glycolysis rather than oxidation of fatty acids. This metabolic switch makes it challenging to distinguish causes from consequences in cardiac pathologies. Finally, despite the progress achieved in the past few decades, medical treatments have not improved substantially, either. In such a situation, it seems clear that much remains to be learned about cardiac diseases. Therefore, in this review, we will discuss how reconciling dioxygen availability and cardiac metabolic adaptations may contribute to develop full and innovative strategies from bench to bedside.

O-GlcNAcylation is a ubiquitous post-translational modification regulated by O-GlcNAcase (OGA) and O-GlcNAc transferase (OGT) in response to environmental and genetic alterations. It occurs in the nucleus, mitochondrion, and cytoplasm and is implicated in cardiovascular disease (CVD) development. O-GlcNAcylation modulates diverse cellular processes, including metabolic pathways, signaling networks, and transcriptional programs. Acute increase in O-GlcNAcylation serves as an adaptive response that preserves cardiac function, whereas chronic elevation leads to persistent metabolic dysregulation and promotes pathological cardiac remodeling. In this review, we provide a comprehensive overview of the role of O-GlcNAcylation across diverse disease contexts. We also summarize the current understanding of its complex interplay with CVD, including the underlying mechanisms. Finally, we highlight existing knowledge gaps and discuss the therapeutic potential of targeting O-GlcNAcylation in various cardiovascular events, emphasizing key priorities for future research.

Introduction: Animal models of cardiac dysfunction and heart failure play important roles in preclinical study and drug discovery. Cardiovascular disease and metabolic dysfunction-associated steatohepatitis (MASH) are closely associated metabolic disorders that frequently coexist in individuals with obesity and metabolic syndrome. However, the mechanisms linking diet-induced metabolic stress to cardiac dysfunction and hepatic pathology remain understudied. Method: In this study, six-week-old C57Bl/6J male mice were fed standard normal chow or a Gubra Amylin NASH (GAN) diet for six months to investigate the concurrent cardiac and hepatic manifestations. Results: Our results indicated that GAN diet-fed mice developed early cardiac dysfunction characterized by reduced ejection fraction (EF) and impaired diastolic function, as indicated by increased E/A and E/E′ ratios. These cardiac changes were accompanied by worsening hepatic pathology, including elevated total cholesterol (TC) and liver injury markers such as ALT, AST and ALP. By 6 months, mice developed pronounced fibrotic remodeling and inflammation in both the heart and liver, as confirmed by histopathological and gene expression analyses. Metabolic assessments further demonstrated a decreased respiratory exchange ratio (RER) in GAN diet-fed mice, particularly during the dark cycle, suggesting enhanced lipid utilization and decreased metabolic flexibility. In addition, reduced oxygen consumption, carbon dioxide production, and locomotor activity suggested impaired energy expenditure and reduced physical activity levels. Conclusion: Collectively, our findings demonstrate that chronic GAN diet feeding induces early cardiac dysfunction accompanied by progressive MASH-like hepatic pathology, with inflammation and fibrotic remodeling developing in both the heart and liver. These findings establish GAN diet feeding as a useful model for investigating the concurrent cardiac and hepatic consequences of chronic metabolic stress.