Abstract
Introduction: Regular physical training associated with nutritional health has broad benefits for the health of the gut microbiota, acting positively on almost all organic systems in the body. In this sense, microRNAs (miRs) have emerged as critical regulators of numerous biological processes, modulating gene expression at the post-transcriptional level. Objective: It was to carry out a systematic review to elucidate the main considerations of nutrology, microRNAs, adult stem cells, and gut microbiota in the process of muscle regeneration in athletes. Methods: The systematic review rules of the PRISMA Platform were followed. The research was carried out from August to September 2024 in Scopus, PubMed, Science Direct, Scielo, and Google Scholar databases. The quality of the studies was based on the GRADE instrument and the risk of bias was analyzed according to the Cochrane instrument. Results and Conclusion: A total of 237 articles were found, and 107 articles were evaluated in full, and 52 were included and developed in this systematic review study. Considering the Cochrane tool for risk of bias, the overall assessment resulted in 47 studies with a high risk of bias and 70 studies that did not meet GRADE. miRs play an important role as regulatory molecules during the muscle healing process. Myoblasts are known to secrete exosomes enriched with miRs into the inflammatory environment, whereby miR-224 is transferred to macrophages to inhibit M2 polarization. Additional data demonstrate that WNT-9a may be a direct target of miR-224 for macrophage polarization. The results showed that miR-122 and myogenic markers were down-regulated in C2C12 cells after TGF-β stimulation, and overexpression of miR-122 can restore myogenesis inhibited by TGF-β. Evidence suggests that the exosome derived from mesenchymal stem cells exhibits functions similar to mesenchymal stem cells with low immunogenicity and without tumorization. High rates of intestinal self-renewal are enabled by intestinal stem cells (LGR5+) at the base of intestinal crypts. LGR5+ activity, including proliferation and differentiation rates, is affected by large shifts in nutrient availability, as occurs on a high-fat diet or fasting. The practice of physical activity, endogenous metabolites, and dietary nutrients can directly influence epigenetic enzymes. Dietary manipulations and metabolites can affect tissue stem cell fate decisions. Self-renewal and differentiation of mesenchymal stem cells can be regulated by manipulating vitamin C, A, or D levels and valine restriction.