A study suggests that the central-western Greenland Ice Sheet (GIS) is approaching a critical transition and will undergo significantly enhanced melting in the near future.
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Edited by Robert Langer, Massachusetts Institute of Technology, Cambridge, MA, and approved July 14, 2011 (received for review June 16, 2011)
Abstract
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 demonstrate that 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 perichondrium layer, which contains a CD44+ CD90+ self-renewing stem/progenitor population and was maintained without calcification or tumor formation even after 10 mo. This is a unique report demonstrating the presence of stem cells in auricular cartilage. Utilization of CSPCs will provide a promising reconstructive material for treating craniofacial defects with successful long-term tissue restoration.
Footnotes
↵1S.K. and T.T. contributed equally to this work.
- ↵2To whom correspondence should be addressed. E-mail: rtanigu{at}med.yokohama-cu.ac.jp.
Author contributions: S.K., T.T., and H.T. designed research; S.K., T.T., M.I., S.I., and H.K. performed research; Y.-W.Z. and J.M. contributed new reagents/analytic tools; S.K., T.T., Y.-W.Z., and H.T. analyzed data; and T.T. and H.T. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1109767108/-/DCSupplemental.
Freely available online through the PNAS open access option.
Reconstruction of human elastic cartilage by a CD44+ CD90+ stem cell in the ear perichondrium
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