• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.31 no.1
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• pp.39-45
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• 2005

Stem cell therapy using mesenchymal stem cells(MSCs) transplantation have been paid attention because of their powerful proliferation and pluripotent differentiating ability. Although umbilical cord blood (UCB) is well known to be a rich source of hematopoietic stem cells with practical and ethical advantages, the presence of mesenchymal stem cells (MSCs) in UCB has been controversial and it remains to be validated. In this study, we examine the presence of MSCs in UCB harvests and the prevalence of them is compared to that of endothelial progenitor cells. For this, CD34+ and CD34- cells were isolated and cultured under the endothelial cell growth medium and mesenchymal stem cell growth medium respectively. The present study showed that ESC-like cells could be isolated and expanded from preterm UCBs but were not acquired efficiently from full-terms. They expressed CD14-, CD34-, CD45-, CD29+, CD44+, CD105+ cell surface marker and could differentiate into adipogenic and osteogenic lineages. Our results suggest that MSCs are fewer in full-term UCB compared to endothelial progenitor cells.

• Biomedical Engineering Letters
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• v.8 no.4
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• pp.393-398
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• 2018

This is the first study demonstrating the efficacy of menstrual blood-derived stem cell (MenSC) transplantation via decellularized human amniotic membrane (DAM), for the promotion of skin excisional wound repair. The DAM was seeded with MenSCs at the density of $3{\times}10^4cells/cm^2$ and implanted onto a rat's $1.50{\times}1.50cm^2$ full-thickness excisional wound defect. The results of wound closure and histopathological examinations demonstrated that the MenSC-seeded DAM could significantly improve the wound healing compared with DAM-treatment. All in all, our data indicated that the MenSCs can be a potential source for cell-based therapies to regenerate skin injuries.

• International Journal of Stem Cells
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• v.16 no.1
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• pp.16-26
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• 2023

Despite long-term research achievements, the development of cell therapy (CT) products remains challenging. This is because the risks experienced by the subject and therapeutic effects in the clinical trial stage are unclear due to the various uncertainties of CT when administered to humans. Nevertheless, as autologous cell products for systemic administration have recently been approved for marketing, CT product development is accelerating, particularly in the field of unmet medical needs. The human experience of CT remains insufficient compared with other classes of pharmaceuticals, while there are countless products for clinical development. Therefore, for many sponsors, understanding the rationale of human application of an investigational product based on the consensus and improving the ability to apply it appropriately for CT are necessary. Thus, defining the level of evidence for safety and efficacy fundamentally required for initiating the clinical development and preparing it using a reliable method for CT. Furthermore, the expertise should be strengthened in the design of the first-in-human trial, such as the starting dose and dose-escalation plan, based on a sufficiently acceptable rationale. Cultivating development professionals with these skills will increase the opportunity for more candidates to enter the clinical development phase.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.164.2-164.2
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• 2003

Human embryonic stem (ES) cell lines derived from the inner cell mass of human blastocysts have potential to differentiate into any cell types. We have established in vitro neural differentiation of human ES cells. After the formation of embroid bodies (EBs), the differentiating EBs formed neural tube-like rosettes in the presence of basic fibroblast growth factor (bFGF). The rosettes were selectively isolated by the treatment of dispase and cultured in a medium for human neural precursors in the presence of bFGF. (omitted)

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.9
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• pp.1152-1158
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• 2010

In differentiating human embryonic stem (d-hES) cells there are a number of types of cells which may secrete various nutrients and helpful materials for pre-implantation embryonic development. This study examined whether the d-hES could function as a feeder cell in vitro to support mouse embryonic development. By RT-PCR analysis, the d-hES cells revealed high expression of three germ-layered differentiation markers while having markedly reduced expression of stem cell markers. Also, in d-hES cells, LIF expression in embryo implantation-related material was confirmed at a similar level to undifferentiated ES cells. When mouse 2PN embryos were cultured in control M16 medium, co-culture control CR1aa medium or co-cultured with d-hES cells, their blastocyst development rate at embryonic day 4 (83.9%) were significantly better in the d-hES cell group than in the CR1aa group (66.0%), while not better than in the M16 group (90.7%)(p<0.05). However, at embryonic days 5 and 6, embryo hatching and hatched-out rates of the dhES cell group (53.6 and 48.2%, respectively) were superior to those of the M16 group (40.7 and 40.7%, respectively). At embryonic day 4, blastocysts of the d-hES cell group were transferred into pseudo-pregnant recipients, and pregnancy rate (75.0%) was very high compared to the other groups (M16, 57.1%; CR1aa, 37.5%). In addition, embryo implantation (55.9%) and live fetus rate (38.2%) of the d-hES cell group were also better than those of the other groups (M16, 36.7 and 18.3%, respectively; CR1aa, 23.2 and 8.7%, respectively). These results demonstrated that d-hES cells can be used as a feeder cell for enhancing in vitro and in vivo developmental potential of mouse pre-implantation embryos.

• BMB Reports
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• v.43 no.12
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• pp.830-835
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• 2010

Epigenetic modification of the genome through DNA methylation is the key to maintaining the differentiated state of human embryonic stem cells (hESCs), and it must be reset during differentiation by retinoic acid (RA) treatment. A genome-wide methylation/gene expression assay was performed in order to identify epigenetic modifications of RA-treated hESCs. Between undifferentiated and RA-treated hESCs, 166 differentially methylated CpG sites and 2,013 differentially expressed genes were discovered. Combined analysis of methylation and expression data revealed that 19 genes (STAP2, VAMP8, C10orf26, WFIKKN1, ELF3, C1QTNF6, C10orf10, MRGPRF, ARSE, LSAMP, CENTD3, LDB2, POU5F1, GSPT2, THY1, ZNF574, MSX1, SCMH1, and RARB) were highly correlated with each other. The results provided in this study will facilitate future investigations into the interplay between DNA methylation and gene expression through further functional and biological studies.

• Journal of Plant Biotechnology
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• v.33 no.3
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• pp.195-207
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• 2006

Stem cells are the primordial, initial cells which usually divide asymmetrically giving rise to on the one hand self-renewals and on the other hand progenitor cells with potential for differentiation. Zygote (fertilized egg), with totipotency, deserves the top-ranking stem cell - he totipotent stem cell (TSC). Both the ICM (inner cell mass) taken from the 6 days-old human blastocyst and ESC (embryonic stem cell) derived from the in vitro cultured ICM have slightly less potency for differentiation than the zygote, and are termed pluripotent stem cells. Stem cells in the tissues and organs of fetus, infant, and adult have highly reduced potency and committed to produce only progenitor cells for particular tissues. These tissue-specific stem cells are called multipotent stem cells. These tissue-specific/committed multipotent stem cells, when placed in altered environment other than their original niche, can yield cells characteristic of the altered environment. These findings are certainly of potential interest from the clinical, therapeutic perspective. The controversial terminology 'somatic stem cell plasticity' coined by the stem cell community seems to have been proved true. Followings are some of the recent knowledges related to the stem cell. Just as the tissues of our body have their own multipotent stem cells, cancerous tumor has undifferentiated cells known as cancer stem cell (CSC). Each time CSC cleaves, it makes two daughter cells with different fate. One is endowed with immortality, the remarkable ability to divide indefinitely, while the other progeny cell divides occasionally but lives forever. In the cancer tumor, CSC is minority being as few as 3-5% of the tumor mass but it is the culprit behind the tumor-malignancy, metastasis, and recurrence of cancer. CSC is like a master print. As long as the original exists, copies can be made and the disease can persist. If the CSC is destroyed, cancer tumor can't grow. In the decades-long cancer therapy, efforts were focused on the reducing of the bulk of cancerous growth. How cancer therapy is changing to destroy the origin of tumor, the CSC. The next generation of treatments should be to recognize and target the root cause of cancerous growth, the CSC, rather than the reducing of the bulk of tumor, Now the strategy is to find a way to identify and isolate the stem cells. The surfaces of normal as well as the cancer stem cells are studded with proteins. In leukaemia stem cell, for example, protein CD 34 is identified. In the new treatment of cancer disease it is needed to look for protein unique to the CSC. Blocking the stem cell's source of nutrients might be another effective strategy. The mystery of sternness of stem cells has begun to be deciphered. ESC can replicate indefinitely and yet retains the potential to turn into any kind of differentiated cells. Polycomb group protein such as Suz 12 repress most of the regulatory genes which, activated, are turned to be developmental genes. These protein molecules keep the ESC in an undifferentiated state. Many of the regulator genes silenced by polycomb proteins are also occupied by such ESC transcription factors as Oct 4, Sox 2, and Nanog. Both polycomb and transcription factor proteins seem to cooperate to keep the ESC in an undifferentiated state, pluripotent, and self-renewable. A normal prion protein (PrP) is found throughout the body from blood to the brain. Prion diseases such as mad cow disease (bovine spongiform encephalopathy) are caused when a normal prion protein misfolds to give rise to PrP$^{SC}$ and assault brain tissue. Why has human body kept such a deadly and enigmatic protein? Although our body has preserved the prion protein, prion diseases are of rare occurrence. Deadly prion diseases have been intensively studied, but normal prion problems are not. Very few facts on the benefit of prion proteins have been known so far. It was found that PrP was hugely expressed on the stem cell surface of bone marrow and on the cells of neural progenitor, PrP seems to have some function in cell maturation and facilitate the division of stem cells and their self-renewal. PrP also might help guide the decision of neural progenitor cell to become a neuron.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.38 no.6
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• pp.343-353
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• 2012

Objectives: This aim of this study was to effectively isolate mesenchymal stem cells (hSMSCs) from human submandibular skin tissues (termed hSMSCs) and evaluate their characteristics. These hSMSCs were then chemically induced to the neuronal lineage and analyzed for their neurogenic characteristics in vitro. Materials and Methods: Submandibular skin tissues were harvested from four adult patients and cultured in stem cell media. Isolated hSMSCs were evaluated for their multipotency and other stem cell characteristics. These cells were differentiated into neuronal cells with a chemical induction protocol. During the neuronal induction of hSMSCs, morphological changes and the expression of neuron-specific proteins (by fluorescence-activated cell sorting [FACS]) were evaluated. Results: The hSMSCs showed plate-adherence, fibroblast-like growth, expression of the stem-cell transcription factors Oct 4 and Nanog, and positive staining for mesenchymal stem cell (MSC) marker proteins (CD29, CD44, CD90, CD105, and vimentin) and a neural precursor marker (nestin). Moreover, the hSMSCs in this study were successfully differentiated into multiple mesenchymal lineages, including osteocytes, adipocytes, and chondrocytes. Neuron-like cell morphology and various neural markers were highly visible six hours after the neuronal induction of hSMSCs, but their neuron-like characteristics disappeared over time (24-48 hrs). Interestingly, when the chemical induction medium was changed to Dulbecco's Modified Eagle Medium (DMEM) supplemented with fetal bovine serum (FBS), the differentiated cells returned to their hSMSC morphology, and their cell number increased. These results indicate that chemically induced neuron-like cells should not be considered true nerve cells. Conclusion: Isolated hSMSCs have MSC characteristics and express a neural precursor marker, suggesting that human skin is a source of stem cells. However, the in vitro chemical neuronal induction of hSMSC does not produce long-lasting nerve cells and more studies are required before their use in nerve-tissue transplants.

• Biomolecules & Therapeutics
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• v.23 no.6
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• pp.517-524
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• 2015

Human mesenchymal stem cells (MSCs) have been used in cell-based therapy to promote revascularization after peripheral or myocardial ischemia. High levels of reactive oxygen species (ROS) are involved in the senescence and apoptosis of MSCs, causing defective neovascularization. Here, we examined the effect of the natural antioxidant lycopene on oxidative stress-induced apoptosis in MSCs. Although $H_2O_2$ ($200{\mu}M$) increased intracellular ROS levels in human MSCs, lycopene ($10{\mu}M$) pretreatment suppressed $H_2O_2$-induced ROS generation and increased survival. $H_2O_2$-induced ROS increased the levels of phosphorylated p38 mitogen activated protein kinase (MAPK), Jun-N-terminal kinase (JNK), ataxia telangiectasia mutated (ATM), and p53, which were inhibited by lycopene pretreatment. Furthermore, lycopene pretreatment decreased the expression of cleaved poly (ADP ribose) polymerase-1 (PARP-1) and caspase-3 and increased the expression of B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (Bax), which were induced by $H_2O_2$ treatment. Moreover, lycopene significantly increased manganese superoxide dismutase (MnSOD) expression and decreased cellular ROS levels via the PI3K-Akt pathway. Our findings show that lycopene pretreatment prevents ischemic injury by suppressing apoptosis-associated signal pathway and enhancing anti-oxidant protein, suggesting that lycopene could be developed as a beneficial broad-spectrum agent for the successful MSC transplantation in ischemic diseases.

• Biomolecules & Therapeutics
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• v.21 no.3
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• pp.196-203
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• 2013

Recent accumulating studies have reported that hypoxic preconditioning during ex vivo expansion enhanced the self-renewal or differentiation of various stem cells and provide an important strategy for the adequate modulation of oxygen in culture conditions, which might increase the functional bioactivity of these cells for cardiac regeneration. In this study, we proposed a novel priming protocol to increase the functional bioactivity of cardiac progenitor cells (CPCs) for the treatment of cardiac regeneration. Firstly, patient-derived c-$kit^+$ CPCs isolated from the atrium of human hearts by enzymatic digestion and secondly, pivotal target molecules identified their differentiation into specific cell lineages. We observed that hCPCs, in response to hypoxia, strongly activated ERK phosphorylation in ex vivo culture conditioning. Interestingly, pre-treatment with an ERK inhibitor, U0126, significantly enhanced cellular proliferation and tubular formation capacities of CPCs. Furthermore, we observed that hCPCs efficiently maintained the expression of the c-kit, a typical stem cell marker of CPCs, under both hypoxic conditioning and ERK inhibition. We also show that hCPCs, after preconditioning of both hypoxic and ERK inhibition, are capable of differentiating into smooth muscle cells (SMCs) and cardiomyocytes (CMs), but not endothelial cells (ECs), as demonstrated by the strong expression of ${\alpha}$-SMA, Nkx2.5, and cTnT, respectively. From our results, we conclude that the functional bioactivity of patient-derived hCPCs and their ability to differentiate into SMCs and CMs can be efficiently increased under specifically defined culture conditions such as short-term hypoxic preconditioning and ERK inhibition.