Age-related muscle decline affects nearly every adult over 50, yet no approved treatments exist for sarcopenia—the progressive loss of muscle strength that undermines independence and quality of life. This paradigm may be shifting as researchers identify an unexpected therapeutic target in the ghrelin receptor, traditionally associated with appetite stimulation.
Deleting the ghrelin receptor (GHSR-1a) in aging mice produced remarkable improvements in muscle fatigue resistance, endurance, and strength without changing muscle mass or lifespan. The benefits extended to pharmacological blocking using the inverse agonist PF-5190457, which mimicked genetic deletion effects. Both interventions enhanced mitochondrial biogenesis through elevated PGC-1α expression and improved mitochondrial quality control via enhanced mitophagy signaling pathways including PINK1/p62, LC3II, and Bnip3. Proteomics analysis confirmed mitochondrial components as central to preserving muscle function during aging.
This finding challenges conventional thinking about ghrelin's role in muscle health. While ghrelin typically stimulates appetite and has acute anabolic effects, chronic receptor blockade appears beneficial for aging muscle by optimizing cellular energy production. The mitochondrial focus is particularly significant since muscle fatigue and weakness often stem from impaired energy metabolism rather than simple mass loss. However, these results come from male mice only, and the optimal timing, dosing, and safety profile for human applications remain unknown. The availability of an existing pharmaceutical compound (PF-5190457) could accelerate clinical translation, potentially offering the first targeted therapy for age-related muscle decline.
