To investigate auricular reconstruction by tissue engineering means, this study compared cartilage regenerated from human chondrocytes obtained from either
microtia or normal (conchal) tissues discarded from otoplasties. Isolated cells were expanded in vitro, seeded onto nanopolyglycolic
acid (nanoPGA) sheets with or without addition of bone morphogenetic protein-7 (BMP7), and implanted in nude mice for 10 weeks. On specimen harvest, cartilage development was assessed by gross morphology, histology, and RT-qPCR and microarray analyses. Neocartilages from normal and
microtia surgical tissues were found equivalent in their dimensions, qualitative degree of
proteoglycan and elastic fiber staining, and quantitative gene expression levels of types II and III
collagen,
elastin, and SOX5. Microarray analysis, applied for the first time for normal and
microtia neocartilage comparison, yielded no genes that were statistically significantly different in expression between these two sample groups. These results support use of
microtia tissue as a cell source for normal auricular reconstruction. Comparison of normal and
microtia cells, each seeded on nanoPGA and supplemented with BMP7 in a slow-release
hydrogel, showed statistically significant differences in certain genes identified by microarray analysis. Such differences were also noted in several analyses comparing counterpart seeded cells without BMP7. Summary data suggest a possible application for BMP7 in
microtia cartilage regeneration and encourage further studies to elucidate whether such genotypic differences translate to phenotypic characteristics of the human microtic ear. The present work advances understanding relevant to the potential clinical use of
microtia surgical remnants as a suitable cell source for tissue engineering of the pinna.