• Molecules and Cells
• /
• v.19 no.1
• /
• pp.46-53
• /
• 2005

Human embryonic stem (hES) cells, unlike most cells derived from adult or fetal human tissues, represent a potentially unlimited source of various cell types for basic clinical research. To meet the increased demand for characterized hES cell lines, we established and characterized nine new lines obtained from frozen-thawed pronucleus-stage embryos. In addition, we improved the derivation efficiency from inner cell masses (to 47.4%) and optimized culture conditions for undifferentiated hES cells. After these cell lines had been maintained for over a year in vitro, they were characterized comprehensively for expression of markers of undifferentiated hES cells, karyotype, and in vitro/in vivo differentiation capacity. All of the cell lines were pluripotent, and one cell line was trisomic for chromosome 3. Improved culture techniques for hES cells should make them a good source for diverse applications in regenerative medicine, but further investigation is needed of their basic biology.

• 대한생식의학회:학술대회논문집
• /
• 2007.06a
• /
• pp.125-125
• /
• 2007

• 대한생식의학회:학술대회논문집
• /
• 2007.06a
• /
• pp.127-127
• /
• 2007

• 대한생식의학회:학술대회논문집
• /
• 2007.06a
• /
• pp.123-123
• /
• 2007

• BMB Reports
• /
• v.49 no.4
• /
• pp.197-198
• /
• 2016

Although three different research groups have reported successful derivations of human somatic cell nuclear transfer-derived embryonic stem cell (SCNT-ESC) lines using fetal, neonatal and adult fibroblasts, the extremely poor development of cloned embryos has hindered its potential applications in regenerative medicine. Recently, however, our group discovered that the severe methylation of lysine 9 in Histone H3 in a human somatic cell genome was a major SCNT reprogramming barrier, and the overexpression of KDM4A, a H3K9me3 demethylase, significantly improved the blastocyst formation of SCNT embryos. In particular, by applying this new approach, we were able to produce multiple SCNT-ES cell lines using oocytes obtained from donors whose eggs previously failed to develop to the blastocyst stage. Moreover, the success rate was closer to 25%, which is comparable to that of IVF embryos, so that our new human SCNT method seems to be a practical approach to establishing a pluripotent stem cell bank for the general public as well as for individual patients.

• 대한생식의학회:학술대회논문집
• /
• 2003.12a
• /
• pp.102-103
• /
• 2003

• Journal of Periodontal and Implant Science
• /
• v.40 no.6
• /
• pp.265-270
• /
• 2010

Purpose: The aim of this study was to investigate the immunomodulatory effects of canine periodontal ligament stem cells on allogenic and xenogenic immune cells in vitro. Methods: Mixed cell cultures consisting of canine stem cells (periodontal ligament stem cells and bone marrow stem cells) and allogenic canine/xenogenic human peripheral blood mononuclear cells (PBMCs) were established following the addition of phytohemagglutinin. The proliferation of PBMCs was evaluated using the MTS assay. The cell division of PBMCs was analyzed using the CFSE assay. The apoptosis of PBMCs was assessed using the trypan blue uptake method. Results: Periodontal ligament stem cells and bone marrow stem cells inhibited the proliferation of allogenic and xenogenic PBMCs. Both periodontal ligament stem cells and bone marrow stem cells suppressed the cell division of PBMCs despite the existence of a mitogen. No significant differences in the percentages of apoptotic PBMCs were found among the groups. Conclusions: Canine periodontal ligament stem cells have an immunomodulatory effect on allogenic and xenogenic PBMCs. This effect is not a product of apoptosis of PBMCs but is caused by the inhibition of cell division of PBMCs.

• Journal of Biomedical Engineering Research
• /
• v.31 no.2
• /
• pp.87-93
• /
• 2010

Researches for stem cells have been focused on scientists in biomedical sciences as well as clinical application for its great therapeutic potentials. Stem cells have two distinct characteristics: self-renewal and differentiation. In this short review, the links between stem cell research and biomedical engineering is discussed based on the basic characteristics of stem cells. This concept can be extended to the fundamental questions of biological sciences for cells such as proliferation, apoptosis, differentiation, and migration. For understanding proliferation and apoptosis of stem cells, techniques from biomedical engineering such as surface patterning, MEMS, nanotechnologies have been used. The advanced technologies such as microfluidic technologies, three dimensional scaffold fabrication, and mechanical/electrical stimulation have also been used in cell differentiation and migration. Basic and unsolved questions in the stem cell research field have limitations by studying conventional technologies. Therefore, the strategic fusion between stem cell biology and novel biomedical engineering field will break the barriers for understanding fundamental questions of stem cells, which can open the window for the clinical applications of stem cell based therapeutics as well as regeneration of damaged tissues.

• BMB Reports
• /
• v.55 no.3
• /
• pp.142-147
• /
• 2022

Human pluripotent stem cells (PSCs) have been utilized as a promising source in regenerative medicine. However, the risk of teratoma formation that comes with residual undifferentiated PSCs in differentiated cell populations is most concerning in the clinical use of PSC derivatives. Here, we report that a monoclonal antibody (mAb) targeting PSCs could distinguish undifferentiated PSCs, with potential teratoma-forming activity, from differentiated PSC progeny. A panel of hybridomas generated from mouse immunization with H9 human embryonic stem cells (hESCs) was screened for ESC-specific binding using flow cytometry. A novel mAb, K312, was selected considering its high stem cell-binding activity, and this mAb could bind to several human induced pluripotent stem cells and PSC lines. Cell-binding activity of K312 was markedly decreased as hESCs were differentiated into embryoid bodies or by retinoic acid treatment. In addition, a cell population negatively isolated from undifferentiated or differentiated H9 hESCs via K312 targeting showed a significantly reduced expression of pluripotency markers, including Oct4 and Nanog. Furthermore, K312-based depletion of pluripotent cells from differentiated PSC progeny completely prevented teratoma formation. Therefore, our findings suggest that K312 is utilizable in improving stem cell transplantation safety by specifically distinguishing residual undifferentiated PSCs.

• Journal of Korean Neurosurgical Society
• /
• v.65 no.2
• /
• pp.161-172
• /
• 2022

Although technological advances and clinical studies on stem cells have been increasingly reported in stroke, research targeting hemorrhagic stroke is still lacking compared to that targeting ischemic stroke. Studies on hemorrhagic stroke are also being conducted, mainly in the USA and China. However, little research has been conducted in Korea. In reality, stem cell research or treatment is unfamiliar to many domestic neurosurgeons. Nevertheless, given the increased interest in regenerative medicine and the increase of life expectancy, attention should be paid to this topic. In this paper, we summarized pre-clinical rodent studies and clinical trials using stem cells for hemorrhagic stroke. In addition, we discussed results of domestic investigations and future perspectives on stem cell research for a better understanding.