FNDC5 and sarcopenia: Furthermore, while Huang et al. did not focus on the involvement of adipokines or myokines, our study uncovers a dual regulatory network in which classical adipokines (e.g., RBP4, ITLN1, and LEP) and emergent myokines (e.g., FNDC5 and METRNL) differentially correlate with mitochondrial hub genes, suggesting novel endocrine signatures of sarcopenia and diabetes [15].