• Development and Reproduction
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• v.13 no.4
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• pp.271-280
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• 2009

Human placenta is abundant source of adult stem cells. Especially, amniotic epithelial cells have stem cell characteristics, expressing surface markers normally present on embryonic stem cells and germ cells. However, culturing and expanding amniotic epithelial cells in vitro without feeder cells are difficult due to endogenous characteristics of epithelial cells. In the present study, amniotic epithelial cells are isolated and proliferated in several passages by applying dithiothreitol and a Rho-associated kinase inhibitor in culture media. The cultured amniotic epithelial cells showed the epithelial and stem cell characteristics. In conclusion, human placenta-derived amniotic epithelial stem cells can be a major source of stem cells for medical treatment of various diseases without any controversial issues.

• 대한생식의학회:학술대회논문집
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• 2004.11a
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• pp.73-74
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• 2004

• Clinical and Experimental Reproductive Medicine
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• v.34 no.4
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• pp.219-227
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• 2007

• Clinical and Experimental Reproductive Medicine
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• v.33 no.1
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• pp.25-33
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• 2006

Objective: The aim of this study was to investigate whether embryonic stem (ES) cells can be established from isolated blastomeres of mouse embryos. Methods: Blastomeres were separated from mouse (C57Bl/6J) 2- or 4-cell embryos. Isolated blastomeres or whole 4-cell embryos were co-cultured with mitosis-arrested STO feeder cells in DMEM supplemented with recombinant murine leukemia inhibitory factor and ES-qualified fetal bovine serum. After the tentative ES cell lines were maintained from isolated blastomeres or whole embryos, some of them were frozen and the others were sub-cultured continually. Characteristics of tentative ES cell lines as were evaluated for specific genes expressions with immunocytochemistry and RT-PCR. Results: One ES cell line (3.0%) was established from isolated blastomere of 2-cell embryo and one cell line (4.0%) from isolated two blastomeres of 4-cell embryo. And five cell lines (16.7%) were established from whole 4-cell embryos. Both cell lines from isolated blastomere and whole embryo expressed mouse ES cell specific markers such as SSEA-1, Oct-4 and alkaline phosphatase. Marker genes of three germ layers were expressed from embryoid bodies of both cell lines. Conclusion: This study suggests that mouse ES cells could be established from isolated blastomeres, although the efficiency is lower than whole embryos. This animal model could be applied to establishment of autologous human ES cells from biopsied blastomeres of preimplantation embryos in human IVF-ET program.

• Development and Reproduction
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• v.9 no.2
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• pp.105-114
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• 2005

Embryonic stem(ES) cells have tremendous potential as a cell source for cell-based therapies. Realization of that potential will depend on our ability to understand and manipulate the factors that influence cell fate decision and to develop methods for getting enough cell numbers for clinical applications. Hematopoiesis has been widely studied, and hematopoietic differentiation from ES cells is a good model to study lineage commitment. In this study, we investigated stemness and compared the efficiency of hematopoietic differentiation using two different mouse embryonic stem cell lines TC-1 and B6-1. Although the two cell lines showed known stem cell properties with minor differences, the embryoid body formation efficiency in methylcellulose was much higher in TC-1 than B6-1. When measured potentials of hematopoietic differentiation using functional(colony-forming cell) and phenotypic(specific marker expression) assays, we found that TC-1 can differentiate into hematopoietic cells in methylcellulose culture but B6-1 cannot. These results imply that we can improve the efficiency of hematopoietic cell differentiation by selection of proper cell lines and this may be also applied in the differentiation of human embryonic stem cells.

• Clinical and Experimental Reproductive Medicine
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• v.37 no.1
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• pp.13-23
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• 2010

Objective: The present study was carried out to induce differentiation of human embryonic stem cells (hESCs) into germ cells and to establish a culture condition for single hESCs dissociated by enzyme. Methods: Embryonic body (EB) was formed by hanging drop culture for 3 days from hESCs colony. The EBs were cultured in the medium supplemented with retionic acid (RA) or/and bone morphogenetic protein-4 (BMP4) for 14 days to differentiate into germ cells. Germ cell specific markers, c-kit and VASA were used for immunohistochemistry of EB. Human ESCs colonies were dissociated into single cells by Collagenase, Tryple and Accutase, and then colony formation rate of the single cells was examined. Rho-associated kinase inhibitor (ROCK inhibitor, Y27632) was added into the culture medium of single cells to reduce the apoptotic damage during the dissociation. Results: Single cells dissociated with Tryple or Accutase showed higher colony formation rates compared to the cells dissociated with Collagenase. Seeding of $5{\times}10^3$ cells/well (4 well dish) was efficient to obtain high colony formation rate compared to other concentrations of seeding cell. Addition of Y27632 significantly increased the colony formation rate of the single cells dissociated by Tryple. Immunohistochemistry of EB with c-kit and VASA markers showed a weak fluorescence signals compared to the signals from the testicular tissue. Conclusion: Dissociation with Tryple was useful to obtain healthy single cells and addition of Y27632 was beneficial for survival and colony formation of the single cells. Unlike other studies, we just observed a dim fluorescence staining of the germ cell markers, probably caused by the short-term culture for the differentiation of EB compared to other studies.

• Development and Reproduction
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• v.11 no.2
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• pp.67-77
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• 2007

Replacement of insulin-producing cells represents an almost ideal treatment for patients with diabetes mellitus type 1. Transplantation of pancreatic islets of Langerhans is limited by the lack of donor organs. Therefore, generation of insulin-producing cells from human embryonic stem cells represents an attractive alternative. The present review summarizes the current knowledge on the differentiation of insulin-producing cells from human embryonic stem cells and their application to the cell therapy for treating diabetes mellitus.

• Proceedings of the KSAR Conference
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• 2003.06a
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• pp.6-13
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• 2003

• The Science & Technology
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• no.3 s.418
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• pp.10-13
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• 2004

• 대한생식의학회:학술대회논문집
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• 2004.06a
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• pp.61.2-62
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• 2004