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BioMed Research International
Volume 2013, Article ID 143028, 9 pages
http://dx.doi.org/10.1155/2013/143028
Research Article

In Vitro Culture-Induced Pluripotency of Human Spermatogonial Stem Cells

1Fertility Center of CHA Gangnam Medical Center, College of Medicine, CHA University, 606-5 Yeoksam-dong, Gangnam-gu, Seoul 135-081, Republic of Korea
2Department of Anatomy and Cell Biology, College of Medicine, Hanyang University, Seoul 133-791, Republic of Korea
3Department of Urology, CHA Bundang Medical Center, CHA University, Seongnam 463-712, Republic of Korea
4Department of Biomedical Science, College of Life Science, CHA University, Seoul 135-081, Republic of Korea

Received 27 September 2012; Accepted 29 November 2012

Academic Editor: Thomas Skutella

Copyright © 2013 Jung Jin Lim et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Unipotent spermatogonial stem cells (SSCs) can be transformed into ESC-like cells that exhibit pluripotency in vitro. However, except for mouse models, their characterization and their origins have remained controversies in other models including humans. This controversy has arisen primarily from the lack of the direct induction of ESC-like cells from well-characterized SSCs. Thus, the aim of the present study was to find and characterize pluripotent human SSCs in in vitro cultures of characterized SSCs. Human testicular tissues were dissociated and plated onto gelatin/laminin-coated dishes to isolate SSCs. In the presence of growth factors SSCs formed multicellular clumps after 2–4 weeks of culture. At passages 1 and 5, the clumps were dissociated and were then analyzed using markers of pluripotent cells. The number of SSEA-4-positive cells was extremely low but increased gradually up to ~ 10% in the SSC clumps during culture. Most of the SSEA-4-negative cells expressed markers for SSCs, and some cells coexpressed markers of both pluripotent and germ cells. The pluripotent cells formed embryoid bodies and teratomas that contained derivatives of the three germ layers in SCID mice. These results suggest that the pluripotent cells present within the clumps were derived directly from SSCs during in vitro culture.