Low Intensity Vibrations Augment Proliferation and Differentiation in Aging Mesenchymal Stem Cells

Poor musculoskeletal health is one of the primary contributors to disability among aged individuals. Stem cell aging, typified by reduced proliferative and differentiative capacity, is in-part driven by decreased mechanosensory capabilities of cells –observed as attenuated exercise efficacy in older individuals. A principal source of mechanical signals that are universally recognized to maintain a healthy musculoskeletal system is exercise. A primary component of exercise, mechanical signals, when applied in the form of low intensity vibration (LIV), increases Mesenchymal Stem Cell (MSC) osteogenesis and decreases adipogenesis. Therefore, we asked if continuous application of LIV would increase proliferation and differentiation in an in vitro aging model. Two identical set of MSCs were kept sub-confluent (\u3c60%) and passaged twice weekly, while one set was LIV treated (Indicated as P5L, P7L etc…) twice daily (20min at 90Hz, 0.7g) the other set was not vibrated (indicated as P5, P7 etc...). LIV promoted proliferation rates, increasing cell-doubling 81% (p\u3c0.05) over 40 passages which resulted in 47% shorter telomeres (p\u3c0.05). Osteogenic capacity measured by ALP (Alkaline Phosphatase) expression at P30 against young P6 MSCs remained 58% higher in LIV-treated P30L MSCs (p\u3c0.05). In summary our findings that despite having shorter telomeres, long term LIV-treated MSCs remain proliferative, pro-osteogenic. We are currently investigating effects of long term LIV on acute FAK signaling, osteogenesis, adipogenesis and extracellular matrix deposition