Clinical review of bone regenerative medicine and maxillomandibular reconstruction

We have studied bone regenerative medicine to employ autologous bone marrow stromal cells and platelet-rich plasma as tissue-engineered osteogenic materials. Although our studies have been successful to a certain degree, advancing to clinical applications, the strategy for practical use of this method has to be changed, because the environment surrounding bone regenerative medicine has evolved dramatically. Therefore, we have changed our focus from cells to cell-conditioned media, and we found that the latter contains growth factors and matrices released from the cells and promotes regeneration of tissues by recruiting endogenous stem cells and precursor cells, and thereby started clinical research based on these findings. However, the amount of regeneration achieved is minimal (mm), and the centimeter-scale reconstruction of segmental bone defects is still a challenge. We have focused our attention on distraction osteogenesis, which is an excellent model for in vivo tissue regeneration of segmental defects, and we have investigated and clarified its mechanisms at a cellular level, based on tissue regeneration processes. The strategy has been investigated to promote vascularization, as it should precede tissue regeneration. A potential approach for enabling tissue regeneration that mimics distraction osteogenesis without using a distraction device is discussed.