Metabolic rewiring and inter-organ crosstalk in diabetic HFpEF

Heart failure with preserved ejection fraction (HFpEF) represents a significant and growing clinical challenge. Initially, for an extended period, HFpEF was simply considered as a subset of heart failure, manifesting as haemodynamic disorders such as hypertension, myocardial hypertrophy, and diastolic dysfunction. However, the rising prevalence of obesity and diabetes has reshaped the HFpEF phenotype, with nearly 45% of cases coexisting with diabetes. Currently, it is recognized as a multi-system disorder that involves the heart, liver, kidneys, skeletal muscle, adipose tissue, along with immune and inflammatory signaling pathways. In this review, we summarize the landscape of metabolic rewiring and the crosstalk between the heart and other organs/systems (e.g., adipose, gut, liver and hematopoiesis system) in diabetic HFpEF for the first instance. A diverse array of metabolites and cytokines play pivotal roles in this intricate crosstalk process, with metabolic rewiring, chronic inflammatory responses, immune dysregulation, endothelial dysfunction, and myocardial fibrosis identified as the central mechanisms at the heart of this complex interplay. The liver-heart axis links nonalcoholic steatohepatitis and HFpEF through shared lipid accumulation, inflammation, and fibrosis pathways, while the gut-heart axis involves dysbiosis-driven metabolites (e.g., trimethylamine N-oxide, indole-3-propionic acid and short-chain fatty acids) impacting cardiac function and inflammation. Adipose-heart crosstalk highlights epicardial adipose tissue as a source of local inflammation and mechanical stress, whereas the hematopoietic system contributes via immune cell activation and cytokine release. We contend that, based on the viewpoints expounded in this review, breaking this inter-organ/system vicious cycle is the linchpin of treating diabetic HFpEF.