The multifaceted roles of ketones in physiology

The production of ketones, referred to as ketogenesis, plays an essential role in maintaining energy homeostasis during prolonged fasting/starvation, which primarily stems from its ability to serve as a fuel source to support neuronal ATP production, thereby limiting muscle wasting. Over the years, the field has come to appreciate that ketones are much more than just a fuel source supporting neuronal metabolism, as many other oxidative organs, such as the heart and skeletal muscle, are capable of metabolizing ketones. Furthermore, ketones appear to be an important fuel source for exercising muscle. Beyond supporting ATP production, it is also becoming widely recognized that ketones are powerful signalling molecules, as they serve as ligands for G-protein coupled receptors and can even modify gene expression via regulating DNA post-translational modifications. As they play a key role in supporting whole-body physiology, it is not surprising that perturbations in ketone metabolism can contribute to various pathologies, particularly in relation to cardiometabolic diseases. Some of the strongest evidence supporting the aforementioned statement is seen for both heart failure and type 2 diabetes. Accordingly, we will review herein the multifaceted roles of ketones in supporting whole-body physiology, while interrogating the evidence to suggest whether modifying ketone metabolism may have a therapeutic role in the management of heart failure and type 2 diabetes.