Skeletal muscle – A bystander or influencer of metabolic syndrome?

Background and aims: Metabolic syndrome is the concurrent presentation of multiple cardiovascular risk factors, including obesity, insulin resistance, hyperglycemia, dyslipidemia and hypertension. It has been suggested that some of these risk factors can have detrimental effects on the skeletal muscle while others can be a direct result of skeletal muscle abnormalities, showing a two-way directionality in the pathogenesis of the condition. This review aims to explore this bidirectional correlation by discussing the impact of metabolic syndrome on skeletal muscle tissue in general and will also discuss ways in which skeletal muscle alterations may contribute to the pathogenesis of metabolic syndrome. Methods: Literature searches were conducted with key words (e.g. metabolic syndrome, skeletal muscle, hyperglycemia) using PubMed, EBSCOhost, Science Direct and Google Scholar. All article types were included in the search. Results: The pathological mechanisms associated with metabolic syndrome, such as hyperglycemia and inflammation, have been associated with changes in skeletal muscle fiber composition, metabolism, insulin sensitivity, mitochondrial function, and strength. Additionally, some skeletal muscle alterations, particularly mitochondrial dysfunction and insulin resistance, are suggested to contribute to the development of metabolic syndrome. For example, the suggested underlying mechanisms of sarcopenia development are also contributors to metabolic syndrome pathogenesis. Conclusion: Whilst numerous studies have identified a relationship between metabolic syndrome and skeletal muscle abnormalities, further investigation into the underlying mechanisms is needed to elucidate the best prevention and management strategies for these conditions.