Regulation of Skeletal Muscle Metabolism by Saturated and Monounsaturated Fatty Acids

Abstract

Abstract Skeletal muscle metabolism and function is regulated by different signaling pathways which are activated or repressed by nutritional, hormonal, inflammatory, and nervous stimuli. Lipids are used as a major fuel source in skeletal muscle, but their presence in plasma membrane as phospholipids is critical for the fine tuning of ligand/protein interactions. Furthermore, several intracellular processes are influenced by the ectopic accumulation of lipid mediators [free fatty acids (FAs), ceramides, diacylglycerols (DAGs)] that are then considered to be lipotoxic. FA composition of lipids is a critical element in the effect of different lipid classes. A high proportion of saturated FAs in cellular phospholipids or ceramides was described to negatively affect membrane fluidity and reduce insulin signaling pathways through different mechanisms. In the case of skeletal muscle, this implies an ability to buffer the increase in plasma glucose concentration and stimulate protein anabolism after meal ingestion. This increases the risk of developing several metabolic abnormalities and leads to chronic diseases, such as type 2 diabetes or sarcopenia. The present chapter provides an overview of mechanistic evidences linking the balance between saturated and monounsaturated FAs in cellular lipid fractions and the regulation of skeletal muscle metabolism, notably in response to insulin stimulation