P68 | EARLY EFFECTS OF MECHANOACUSTIC FOCUSED VIBRATION (MFV) ON PRIMARY HUMAN SATELLITE CELLS ISOLATED FROM YOUNG AND OLDER INDIVIDUALS

S. Sancilio¹, G. Stati¹, E.S. Di Filippo², S. Fulle², R. Di Pietro¹ | ¹Department of Medicine and Aging Sciences, “G. d’Annunzio” University of Chieti-Pescara, Chieti, Italy; ²Department of Neuroscience Imaging and Clinical Sciences, “G. d’Annunzio” University of Chieti-Pescara, Chieti, Italy

Skeletal muscle is composed of elongated, multinucleated, and contractile units known as muscle fibers, which can regenerate and repair tissue damage via resident stem cells, called satellite cells (SCs)^1,2. Impaired regeneration and progressive muscle atrophy are hallmarks of sarcopenia, a condition with significant clinical impact, contributing to frailty, functional decline, and comorbidities in the elderly³. Current therapeutic strategies primarily involve physical activity and nutritional support, occasionally combined with rehabilitation approach such as mechanoacoustic stimulation. MFV activates type III and IV mechanoreceptors, including Pacinian and Meissner corpuscles, Golgi tendon organs, and muscle spindle afferents. This stimulation induces the vibratory tonic reflex (VTR), resulting in involuntary muscle contractions via α-motor neuron activation and subsequent recruitment of otherwise inactive fibers⁴. However, the direct effect of vibration on satellite cells remains to explore. In this study, we examined, after 72 h, the effects of MFV stimulation with increasing time intervals (10, 20, and 30 min) at a constant intensity (100 mbar) and frequency (300 Hz) on primary human myogenic precursor cells isolated from Vastus Lateralis muscle biopsies of 3 young (23±5) and 3 older (72±9) healthy donors and cultured in vitro. MFV treatment reduced satellite cells apoptosis, increased cell size, alignment and mitotic activity and raised the proportion of activated cells in both agegroups. These effects were more pronounced in aged cells after 20-30 min treatment. All in all, our in vitro results indicate for the first time the presence of direct effects of 2 MFV on human SCs. Interestingly, these effects seem to be age-dependent, with a mainly proliferative response of cells from young subjects and a mainly differentiative response of cells from aged subjects.