Circulating microRNA as novel predictors of skeletal muscle anabolic response in aged humans.

Abstract

Elderly individuals present a reduction in skeletal muscle adaptability in response to resistance exercise. Recently, this anabolic resistance was associated with dysregulation of microRNA expression in skeletal muscle of elderly individuals. Although microRNA expression in skeletal muscle provides important data regarding molecular mechanisms responsible for anabolic resistance and sarcopenia, the need for muscle biopsy may cause discomfort for elderly population, limiting this type of investigation. Therefore, the determination of biomarkers is fundamental for understanding the molecular mechanisms responsible for anabolic resistance and sarcopenia in elderly individuals. Thus, the main aim of this project will be to verify if the responses of the circulating microRNA expression profile are associated with the molecular responses of the skeletal muscle after an acute anabolic stimulus in elderly individuals. For this purpose, peripheral blood and vastus lateralis muscle samples will be collected before, immediately after and 4 hours after an acute resistance exercise protocol in young and old men. The following methods will be used: muscle biopsy, analysis of circulating and skeletal muscle microRNA expressions, bioinformatics analysis, and Ingenuity Pathway Analysis software for the functional analysis of the interaction between circulating and skeletal muscle microRNAs. According to the statistical data distribution, parametric or nonparametric tests will be used to compare the investigated parameters between the experimental groups. The level of significance of p < 0.05 will be adopted.