Reconstruction of human elastic cartilage by a CD44+ CD90+ stem cell in the ear perichondrium

Kobayashi, Shinji; Takebe, Takanori; Inui, Midori; Iwai, Sayaka; Kan, Hiroomi; Zheng, Yun-Wen; Maegawa, Jiro; Taniguchi, Hideki

Despite the great demands for treating craniofacial injuries or abnormalities, effective treatments are currently lacking.One promising approach involves human elastic cartilage reconstruction using autologous stem/progenitor populations. Nevertheless,definitive evidence of the presence of stem cells in human auricular cartilage remains to be established. Here, we demonstratethat human auricular perichondrium, which can be obtained via a minimally invasive approach, harbors a unique cell population,termed as cartilage stem/progenitor cells (CSPCs). The clonogenic progeny of a single CD44+ CD90+ CSPC displays a number of features characteristic of stem cells. Highly chondrogenic CSPCs were shown to reconstruct large(>2 cm) elastic cartilage after extended expansion and differentiation. CSPC-derived cartilage was encapsulated by a perichondriumlayer, which contains a CD44+ CD90+ self-renewing stem/progenitor population and was maintained without calcification or tumor formation even after 10 mo. Thisis a unique report demonstrating the presence of stem cells in auricular cartilage. Utilization of CSPCs will provide a promisingreconstructive material for treating craniofacial defects with successful long-term tissue restoration.