Destiny of autologous bone marrow-derived stromal cells implanted in the vocal fold

Objectives: The aim of this study was to investigate the destiny of implanted autologous bone marrow-derived stromal cells (BSCs) containing mesenchymal stem cells. We previously reported the successful regeneration of an injured vocal fold through implantation of BSCs in a canine model. However, the fate of the implanted BSCs was not examined. In this study, implanted BSCs were traced in order to determine the type of tissues resulting at the injected site of the vocal fold. Methods: After harvest of bone marrow from the femurs of green fluorescent transgenic mice, adherent cells were cultured and selectively amplified. By means of a fluorescence-activated cell sorter, it was confirmed that some cells were strongly positive for mesenchymal stem cell markers, including CD29, CD44, CD49e, and Sca-1. These cells were then injected into the injured vocal fold of a nude rat. Immunohistologic examination of the resected vocal folds was performed 8 weeks after treatment. Results: The implanted cells were alive in the host tissues and showed positive expression for keratin and desmin, markers for epithelial tissue and muscle, respectively. The implanted BSCs differentiated into more than one tissue type in vivo. Conclusions: Cell-based tissue engineering using BSCs may improve the quality of the healing process in vocal fold injuries.