Adipose-derived mesenchymal stem cell spheroid sheet accelerates regeneration of ulcerated oral mucosa by enhancing inherent therapeutic properties

The goal of this study was to investigate the effect of transplantation of an adipose-derived stem cell (ASC) spheroid sheet on the regeneration of ulcerated oral mucosa. The ASC spheroid sheet was constructed by seeding three-dimensional (3D) spheroidal ASCs on a temperature-responsive hydrogel, where cell adhesion and spreading were improved by incorporating fibronectin. The 3D culture of ASCs enhanced their inherent paracrine properties for up to 1 week after transferring to two-dimensional (2D) culture conditions. Expansion of the hydrogel through temperature change promoted effective delivery of ASCs to the site of injury, and viability was maintained after transferring ASCs to the target substrate. Treatment with the ASC spheroid sheet accelerated wound closure and regeneration of the stratified multi-layered epithelium. The regenerated epithelium not only had structural integrity, but also displayed phenotypic polarization across the mucosa; basal epithelial cells expressed cytokeratin 5, whereas cytokeratin 13-positive cells were located in the supra-basal layers. In addition, by day 7 after treatment, the mucosa that received the ASC spheroid sheet had significantly decreased inflammation, similar to that of the normal mucosa. These results demonstrate that the ASC spheroid sheet is an effective treatment for ulcers in the oral cavity.