Unlocking Neuroprotection: Exercise-Induced Muscle Secretome (Myokines) as a Therapeutic Avenue Against Alzheimer's...

This review critically evaluates exercise-induced myokines as neuroprotective agents against Alzheimer's disease (AD) and is structured around three thematic sections: (1) mechanistic foundations of myokine neuroprotection, (2) translational barriers to therapeutic development, and (3) a strategic framework for future research. Epidemiological studies associate physical exercise with reduced AD risk (30-45%), yet mechanisms remain incompletely resolved. Preclinical studies demonstrate that exercise-induced myokines (Irisin, BDNF, Cathepsin B) modulate AD pathology by: (1) attenuating amyloid-beta (Aβ)/tau accumulation, (2) suppressing neuroinflammation, and (3) enhancing synaptic plasticity. However, human exercise interventions show conflicting results influenced by APOE genotype, age, and exercise modality. Associative human data suggest that Interleukin-6 (IL-6) exemplifies pleiotropy-affording neuroprotective effects in acute contexts but potentially detrimental effects in states of chronic inflammation. Therapeutic hurdles include blood-brain barrier (BBB) penetration, pleiotropic risks, and patient heterogeneity. Emerging concepts such as combinatorial approaches (nanocarriers, exercise mimetics) and biomarker-driven trials are proposed as hypothetical future strategies; however, these remain unvalidated and require substantial preclinical development before implemented in clinical care. This narrative review is structured around three thematic sections: mechanistic foundations of myokine neuroprotection, translational barriers to therapeutic development, and a strategic framework for future research. The muscle-brain axis represents a compelling but complex therapeutic target. Based on current preclinical and correlational human evidence, future research should prioritize mechanistic rigor, standardized biomarker validation, and clinically viable delivery strategies. Notably, several approaches discussed herein-including nanocarrier delivery systems, exercise mimetics, and combinatorial myokine cocktails-remain speculative and are presented as future research directions rather than established therapeutic interventions.