15. Gene Expression Profiles from Jaw and Alveolar Bones are Uniquely Different from Profiles of Trunk and Limb Bones

[Purpose] Jaw bones and alveolar both derive from neural crest cells, while bones of the trunk and limbs derive from mesoblasts. Generally, we often use iliac bone for alveolar bone grafting. In this study, we investigated differences in gene expressions from the jaw bone (mandible and maxilla) and from bones of the trunk and limbs (ilium and thigh bone). In addition, we transplanted mandible, maxilla, ilium and thigh bone grafts into calvarial regional defects to assess bone regeneration. [Methods] Gene expressions from the above tissues were evaluated by means of a DNA microarray. Preliminary bone regeneration data from the calvarial defects was evaluated using micro-computed tomography and histological analysis. [Results] Our data indicate that there is a close homology between ilium- and thigh- bone whole gene expressions. However, gene expression profiles from the jaw bone were different from those of the ilium and thigh bones. Specifically, P0, P75, Musashi-1, Nestin, Sox-10 and Slug were expressed more strongly in the jaw bone compared to profiles from the ilium and thigh bones. As expected, histological analysis showed differing bone formation processes between grafts of the jaw bone and of the extremities. [Conclusion] The jaw bone exhibits a unique gene expression profile that is associated with neural crest cells and has a positive influence on bone regeneration when used as a graft material. Thus, full investigation of the biological and mechanical properties of the jaw bone as an alternative graft material for jaw bone reconstructive surgery is recommended.