Role of Triceps Muscle Fiber-Specific Myokines in Pancreatic β-Cell Protection: Implications for Type 2 Diabetes: A Narrative Review.

Background and Aims: Type 2 diabetes (T2D) is a major global health challenge, primarily driven by insulin resistance and progressive β-cell dysfunction aggravated by chronic low-grade inflammation. Skeletal muscle has emerged as a pivotal endocrine organ through the secretion of myokines, which exert systemic metabolic and immunomodulatory effects. Methods: This narrative review was conducted through systematic database searches (PubMed, Scopus, Web of Science, Google Scholar) using predefined keywords related to myokines, type 2 diabetes, β-cell survival, and triceps brachii. Publications from 2010 to 2025 were included based on scientific relevance and thematic suitability. Results: Among known myokines, irisin, FGF21, IL-6, and IL-15 demonstrate beneficial actions on glucose homeostasis, insulin sensitivity, and β-cell survival. Evidence suggests that muscle fiber type composition may influence myokine secretion patterns, with type II fibers, predominant in the triceps brachii, producing distinct bioactive profiles. Notably, angiogenin and osteoprotegerin, associated with type II fiber activity, display cytoprotective effects on pancreatic β-cells by reducing oxidative stress, modulating inflammation, and inhibiting apoptosis. Conflicting data exist, as the type II fiber secretome can also be pro-inflammatory under metabolic stress conditions. Conclusion: Triceps-targeted resistance exercises could represent a promising non-pharmacological strategy to enhance protective myokine release, complementing conventional diabetes management. Nevertheless, most available data derive from preclinical studies, and translational evidence in humans remains scarce. Future research should prioritize longitudinal and interventional studies to validate these findings, assess interindividual variability, and explore therapeutic applications of type II fiber-associated myokines.