Induced Pluripotent Stem (iPS) Cells for the Regeneration of Trachea and Larynx

The treatment of laryngotracheal stenosis remains a challenge. Our previous studies focused on basic research and the clinical applications of an artificial trachea. In this study we focused on the challenge posed by the fact that a prefabricated artificial trachea cannot be utilized for pediatric airways since the tracheal frame needs to expand as the child develops. Induced pluripotent stem(iPS)cells were first generated in 2006. These cells are capable of unlimited symmetrical self-renewal, thus providing an unlimited cell source for tissue-engineering applications. In this report, iPS cells were cultured in a three-dimensional(3 D)scaffold in Chondrocyte Differentiation Medium (CDM). After cultivation, differentiation into chondrocytes was examined. The ratio of undifferentiated cells was analyzed by flow cytometry. The 3D scaffolds were implanted into tracheal defects in 24 nude rats. Differentiation into chondrocytes in vitro was confirmed histologically, phenotypically and genetically. Flow cytometric analysis demonstrated that the population of undifferentiated cells had decreased. Cartilage tissue was observed in the regenerated tracheal wall. The expression of cartilage-specific protein was also demonstrated in vivo. The presence of the green fluorescent protein(GFP)gene derived from iPS cells was confirmed in samples of cartilage tissue by the combination of Laser Microdissection(LMD)and Polymerase Chain Reaction(PCR)techniches. Our results suggest that iPS cells could be a new cell source for the regeneration of the trachea.