The 18th Annual Meeting of the Japanese Research Society of Ultrasound Stimulation for Fracture Repair Abstracts

Mesenchymal Stem Cells (MSCs) are pluripotent cells with the capability of self-renewal. It has been established that MSCs can transform into osteoblasts, adipocytes or chondrocytes depending on the culture condition. Regenerative medicine is considered to become an essential therapy in the field of bone regeneration in the near future. Cell culture of MSCs is relatively easy, but it is technically difficult to maintain their undifferentiated states in vitro. Therefore, development of new cell culture methods to maintain their stemness is needed for successful clinical applications of MSCs. We set up a hypothesis that physical stimulation by ultrasound may be useful for maintaining stemness of MSCs. If the expression of some stem cell-related genes can be induced by applying LIPUS to MSCs, it may be possible in future to develop new methods to maintain the stemness of MSCs in vitro using LIPUS. The expression of Oct4, Nanog, and Sox2, which are the stemness marker genes of MSCs differentiation, was markedly promoted by LIPUS stimulation. Our findings suggest that LIPUS is useful apparatus to develop the cellular engineering for regenerative medicine using MSCs. The results also indicate that mechanical stress is one of the crucial factors to regulate MSC differentiation.