Date Published: January 5, 2016
Publisher: Public Library of Science
Author(s): Mioko Fukahori, Shun-ichi Chitose, Kiminori Sato, Shintaro Sueyoshi, Takashi Kurita, Hirohito Umeno, Yu Monden, Ryoji Yamakawa, Masaya Yamamoto.
Scarred vocal folds result in irregular vibrations during phonation due to stiffness of the vocal fold mucosa. To date, a completely satisfactory corrective procedure has yet to be achieved. We hypothesize that a potential treatment option for this disease is to replace scarred vocal folds with organotypic mucosa. The purpose of this study is to regenerate vocal fold mucosa using a tissue-engineered structure with autologous oral mucosal cells.
Animal experiment using eight beagles (including three controls).
A 3 mm by 3 mm specimen of canine oral mucosa was surgically excised and divided into epithelial and subepithelial tissues. Epithelial cells and fibroblasts were isolated and cultured separately. The proliferated epithelial cells were co-cultured on oriented collagen gels containing the proliferated fibroblasts for an additional two weeks. The organotypic cultured tissues were transplanted to the mucosa-deficient vocal folds. Two months after transplantation, vocal fold vibrations and morphological characteristics were observed.
A tissue-engineered vocal fold mucosa, consisting of stratified epithelium and lamina propria, was successfully fabricated to closely resemble the normal layered vocal fold mucosa. Laryngeal stroboscopy revealed regular but slightly small mucosal waves at the transplanted site. Immunohistochemically, stratified epithelium expressed cytokeratin, and the distributed cells in the lamina propria expressed vimentin. Elastic Van Gieson staining revealed a decreased number of elastic fibers in the lamina propria of the transplanted site.
The fabricated mucosa with autologous oral mucosal cells successfully restored the vocal fold mucosa. This reconstruction technique could offer substantial clinical advantages for treating intractable diseases such as scarring of the vocal folds.
The human vocal fold has a layered structure that consists of the epithelium, lamina propria (superficial, intermediate, and deep layers), and vocalis muscle. The epithelium and lamina propria are especially important for vocal fold vibrations during phonation. Vocal fold scarring can be caused by surgery or iatrogenic injury to the layered structure of the vocal folds. It can lead to replacement of healthy tissue in the vocal fold lamina propria by fibrous tissue, and can disrupt the stratification of the vocal fold epithelium [1, 2].
The morphological and functional characteristics of the tissue-engineered layered mucosa (organotypic culture) closely resembled those of the normal vocal fold epithelium and lamina propria. Moreover, our results suggest that organotypic tissues fabricated from autologous oral mucosa could serve as effective substitutes for allografts in the reconstruction of optimally layered vocal folds. This reconstruction technique could offer substantial clinical advantages over allogeneic transplantation for treating intractable diseases such as scarring of the vocal folds.
This study experimentally fabricated tissue-engineered vocal fold mucosa from canine oral mucosal cells. Using this organotypic cultured mucosa with tissue-engineered autologous oral mucosa, the vocal fold mucosa was successfully restored. Our results suggest that this reconstruction technique could offer substantial clinical advantages for treating intractable diseases such as scarring of the vocal folds.