Masanao Kishimoto

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.

Tracheal Regeneration After Partial Resection: A Tissue Engineering Approach

Objectives: The aims of this study are to investigate the efficiency of a tissue engineering approach to partial tracheal reconstruction and to improve epithelialization of the reconstructed trachea. The trachea must be resected in some cases of cancer or trauma. Various restructuring techniques are used, with no consensus on the best approach. Two problems that arise when treating tracheal defects by conventional techniques are an inability to regenerate ciliated epithelium at the reconstructed site and having to perform multiple procedures to achieve the desired repair. This study is designed to address these problems.

Bone Regeneration of Canine Skull Using Bone Marrow-Derived Stromal Cells and β-Tricalcium Phosphate†

Objective: The aim of this study was to regenerate high‐quality cranial bone using tissue engineering techniques, with subsequent extension to clinical application. Our previous study with a 3‐month observation period indicated that a composite scaffold composed primarily of β‐tricalcium phosphate (TCP) had the potential for cranial bone regeneration. In this study, we investigated whether bone marrow derived stromal cells (BSCs) could promote the regeneration of cranial bone as determined after 3 and 6 months.

Experimental regeneration of canine larynx: a trial with tissue engineering techniques

Conclusion: Since this tissue engineering technique is cost-effective and is less invasive to patients, it may replace conventional approaches in laryngeal reconstructive surgeries. Objective: Laryngeal cancer is one of the most prevalent cancers in the head and neck region, and frequently requires surgical resection. Although there are many ways to reconstruct the larynx after resection, donor tissue is usually required. Recently, tissue engineering techniques have become widely accepted in clinical medicine and have already been applied to some organs. This animal experiment was designed to elucidate the efficacy of laryngeal regeneration using tissue engineering technique. Materials and methods: A bioartificial scaffold was designed from a replica of a canine larynx. A dental cast was used to replicate the intricate inside shape of the larynx. After copying its shape on a polypropylene mesh sheet, this sheet was coated with spongy collagen from porcine skin. A hemilaryngectomy was performed on beagle dogs under general anesthesia. Then the scaffold, preclotted with a mixture of peripheral blood and bone marrow-derived stromal cells, was implanted and fixed. The postoperative status was examined fiberscopically. Results: On the eighth day after the operation, the surface of the implant was covered with soft tissue. Finally, the implant was completely covered with regenerated mucosa.

Cranial bone regeneration using a composite scaffold of Beta-tricalcium phosphate, collagen, and autologous bone fragments.

Objective: The aim of our study was to examine the tissue response and new bone formation induced by β‐tricalcium phosphate (β‐TCP), collagen, and autologous bone fragments with fibrin glue implanted into a cranial bone defect.

Granular cell tumor of hypopharynx : report of a rare case

Granular cell tumor is a rare tumor, probably of Schwann cell origin. The head and neck are most frequently affected, but hypopharyngeal lesion is extremely rare. We report the seventh case of hypopharyngeal granular cell tumor. Immunohistochemical staining for S100 protein is helpful for the correct diagnosis. There is some possibility of malignancy despite absence of histological evidence, thus the treatment is exclusively surgical resection. The microlaryngoscopic approach is feasible for hypopharyngeal lesions in most cases. Recurrence can occur even after appropriate resection.