Ketone ester administration improves glycemia in obese mice

Beta-Hydroxybutyrate Promotes Basal Insulin Secretion While Decreasing Glucagon Secretion in Mouse and Human Islets

Dietary carbohydrates raise blood glucose levels, and limiting carbohydrate intake improves glycemia in patients with type 2 diabetes. Low carbohydrate intake (< 25 g) allows the body to utilize fat as its primary fuel. As a consequence of increased fatty acid oxidation, the liver produces ketones to serve as an alternative energy source. β-Hydroxybutyrate (βHB) is the most abundant ketone. While βHB has a wide range of functions outside of the pancreas, its direct effects on islet cell function remain understudied. We examined human islet secretory response to acute racemic βHB treatment and observed increased insulin secretion at a low glucose concentration of 3 mM. Because βHB is a chiral molecule, existing as both R and S forms, we further studied insulin and glucagon secretion following acute treatment with individual βHB enantiomers in human and C57BL/6J mouse islets. We found that acute treatment with R-βHB increased insulin secretion and decreased glucagon secretion at physiological glucose concentrations in both human and mouse islets. Proteomic analysis of human islets treated with R-βHB over 72 hours showed altered abundance of proteins that may promote islet cell health and survival. Collectively, our data show that physiological concentrations of βHB influence hormone secretion and signaling within pancreatic islets.

Protein succinylation: regulating metabolism and beyond

Modifications of protein post-translation are critical modulatory processes, which alters target protein biological activity，function and/or location, even involved in pathogenesis of some diseases. So far, there are at least 16 types of post-translation modifications identified, particularly through recent mass spectrometry analysis. Among them, succinylation (Ksuc) on protein lysine residues causes a variety of biological changes. Succinylation of proteins contributes to many cellular processes such as proliferation, growth, differentiation, metabolism and even tumorigenesis. Mechanically, Succinylation leads to conformation alteration of chromatin or remodeling. As a result, transcription/expression of target genes is changed accordingly. Recent research indicated that succinylation mainly contributes to metabolism modulations, from gene expression of metabolic enzymes to their activity modulation. In this review, we will conclude roles of succinylation in metabolic regulation of glucose, fat, amino acids and related metabolic disease launched by aberrant succinylation. Our goal is to stimulate extra attention to these still not well researched perhaps important succinylation modification on proteins and cell processes.

The therapeutic potential of ketones in cardiometabolic disease: impact on heart and skeletal muscle

β-Hydroxybutyrate (βOHB) is the major ketone in the body, and it is recognized as a metabolic energy source and an important signaling molecule. While ketone oxidation is essential in the brain during prolonged fasting/starvation, other organs such as skeletal muscle and the heart also use ketones as metabolic substrates. Additionally, βOHB-mediated molecular signaling events occur in heart and skeletal muscle cells, and via metabolism and/or signaling, ketones may contribute to optimal skeletal muscle health and cardiac function. Of importance, when the use of ketones for ATP production and/or as signaling molecules becomes disturbed in the presence of underlying obesity, type 2 diabetes, and/or cardiovascular diseases, these changes may contribute to cardiometabolic disease. As a result of these disturbances in cardiometabolic disease, multiple approaches have been used to elevate circulating ketones with the goal of optimizing either ketone metabolism or ketone-mediated signaling. These approaches have produced significant improvements in heart and skeletal muscle during cardiometabolic disease with a wide range of benefits that include improved metabolism, weight loss, better glycemic control, improved cardiac and vascular function, as well as reduced inflammation and oxidative stress. Herein, we present the evidence that indicates that ketone therapy could be used as an approach to help treat cardiometabolic diseases by targeting cardiac and skeletal muscles.

Exogenous Ketone Supplementation and Ketogenic Diets for Exercise: Considering the Effect on Skeletal Muscle Metabolism

In recent years, ketogenic diets and ketone supplements have increased in popularity, particularly as a mechanism to improve exercise performance by modifying energetics. Since the skeletal muscle is a major metabolic and locomotory organ, it is important to take it into consideration when considering the effect of a dietary intervention, and the impact of physical activity on the body. The goal of this review is to summarize what is currently known and what still needs to be investigated concerning the relationship between ketone body metabolism and exercise, specifically in the skeletal muscle. Overall, it is clear that increased exposure to ketone bodies in combination with exercise can modify skeletal muscle metabolism, but whether this effect is beneficial or detrimental remains unclear and needs to be further interrogated before ketogenic diets or exogenous ketone supplementation can be recommended.