• Proceedings of the PSK Conference
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• 2003.10b
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• pp.100.1-100.1
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• 2003

Tissue engineering has arisen to address the extreme shortage of tissues and organs for transplantation and repair. One of the most successful techniques has been the seeding and culturing cells on three-dimensional biodegradable scaffolds in vitro followed by implantaion in vivo. We used PLA and PLGA as biodegradable polymers and rabbit chondrocytes were isolated and applied to PLA and PLGA to make artificial cartilage. To evaluate the biocompatibility and biological safety of polymers, in vitro cytotoxicity and in vivo animal tests were investigated. (omitted)

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.4
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• pp.541-548
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• 2013

Purpose: Marrow stromal cells (MSCs) have been known for their potential to trans-differentiate into neural and glial cells in vitro and in vivo. To investigate the influence of the developing host environment on the survival and morphological and molecular differentiation, murine MSCs transplanted into the eye of Brazilian opossum (Monodelphis domestica). Methods: Enhanced green fluorescent protein (GFP) - expressing MSCs were transplanted into developing Brazilian opossums. Animals were allowed to survive for up to 4 weeks after transplantation, at which time the eyes were prepared for immunohistochemical analysis. Results: Some transplanted MSCs survived and showed morphological differentiation into neural cells with some processes within the host vitreous chamber. Some transplanted cells expressed class III ${\beta}$-tubulin (TuJ1, a marker for neuronal cells) or glial fibrillary acid protein (GFAP, a marker for glial cells) or Nestin (a marker for neural stem cells). In addition, some transplanted cells were located in ganglion cell layer but did not show morphological and molecular differentiation. Conclusions: Our result show that the most effective stage of development for transplantation into the retina was postnatal day 16, which retinas developmentally corresponded to postnatal day 4-5 days mouse retina based on cell differentiation and lamination patterns. The present findings suggest that the age of the host appears to play a key role in determining cell fate in vivo.

• International Journal of Stem Cells
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• v.15 no.2
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• pp.113-121
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• 2022

The ultimate goal of regenerative medicine is to replace damaged cells, tissues or whole organs, in order to restore their proper function. Stem cell related technologies promise to generate transplants from the patients' own cells. Novel approaches such as blastocyst complementation combined with genome editing techniques open up new perspectives for organ replacement therapies. This review summarizes recent advances in the field and highlights the challenges that still remain to be addressed.

• Archives of Plastic Surgery
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• v.45 no.2
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• pp.111-117
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• 2018

Background Fat grafting, or lipofilling, represent frequent clinically used entities. The fate of these transplants is still not predictable, whereas only few animal models are available for further research. Quantum dots (QDs) are semiconductor nanocrystals which can be conveniently tracked in vivo due to photoluminescence. Methods Fat grafts in cluster form were labeled with cadmium-telluride (CdTe)-QD 770 and transplanted subcutaneously in a murine in vivo model. Photoluminescence levels were serially followed in vivo. Results Tracing of fat grafts was possible for 50 days with CdTe-QD 770. The remaining photoluminescence was $4.9%{\pm}2.5%$ for the QDs marked fat grafts after 30 days and $4.2%{\pm}1.7%$ after 50 days. There was no significant correlation in the relative course of the tracking signal, when vital fat transplants were compared to non-vital graft controls. Conclusions For the first-time fat grafts were tracked in vivo with CdTe-QDs. CdTe-QDs could offer a new option for in vivo tracking of fat grafts for at least 50 days, but do not document vitality of the grafts.

• Animal cells and systems
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• v.5 no.2
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• pp.91-99
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• 2001

Vertebrates regenerate tissues in three ways: proliferation of cells that maintain some or all of their differentiated structure and function, redifferentiation of mature cells followed by proliferation and redifferentiation into the same cell type or transdetermination to another cell type, and activation of restricted lineage stem cells, which have the ability to transdetermine to different lineages under the appropriate conditions. The behavior of the cells during regeneration is regulated by growth factors and extracellular matrix molecules. Some non-regenerating tissues are now known to harbor stem cells which, though they form scar tissue in vivo, are capable of producing new tissue-specific cells in vitro, suggesting that the injury environment inhibits latent regenerative capacity. Regenerative medicine seeks to restore tissues via transplantation of stem cell derivatives, implantation of bioartificial tissues, or stimulation of regeneration in vivo. These approaches have been partly successful, but several research issues must be addressed before regenerative medicine becomes a clinical reality.

• Molecules and Cells
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• v.41 no.6
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• pp.515-522
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• 2018

Patients with head and neck cancer are treated with therapeutic irradiation, which can result in irreversible salivary gland dysfunction. Because there is no complete cure for such patients, stem cell therapy is an emerging alternative for functional restoration of salivary glands. In this study, we investigated in vitro characteristics of primarily isolated epithelial cells from human salivary gland (Epi-SGs) and in vivo formation of acini-like structures by Epi-SGs. Primarily isolated Epi-SGs showed typical epithelial cell-like morphology and expressed E-cadherin but not N-cadherin. Epi-SGs expressed epithelial stem cell (EpiSC) and embryonic stem cell (ESC) markers. During long-term culture, the expression of EpiSC and ESC markers was highly detected and maintained within the core population with small size and low cytoplasmic complexity. The core population expressed cytokeratin 7 and cytokeratin 14, known as duct markers indicating that Epi-SGs might be originated from the duct. When Epi-SGs were transplanted in vivo with Matrigel, acini-like structures were readily formed at 4 days after transplantation and they were maintained at 7 days after transplantation. Taken together, our data suggested that Epi-SGs might contain stem cells which were positive for EpiSC and ESC markers, and Epi-SGs might contribute to the regeneration of acini-like structures in vivo. We expect that Epi-SGs will be useful source for the functional restoration of damaged salivary gland.

• KSBB Journal
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• v.19 no.3
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• pp.210-214
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• 2004

Whole liver transplantation, the currently available treatment of end-stage liver disease, has limitations including serious donor shortage, fatal surgical complications, risk of allograft rejection, and the requirement of life-long immunosuppression. In this study, we investigated the possibility of reconstructing liver tissues in vivo by implanting fetal hepatocytes on polymer scaffolds as a potential method to replace the current treatments. Fetal hepatocytes were freshly isolated from mice and seeded onto porous mesh scaffolds fabricated from polyglycolic acid, a biodegradable synthetic polymer. The seeded scaffolds were implanted into peritoneal cavity of athymic mice for one week. As a control, fetal hepatocytes were implanted without scaffold. One week after transplantation, liver-like tissues formed. Histological and immunohistochemical analyses indicated that the hepatocyles and liver tissue structures (bile ducts) were present in the newly formed tissues. In the control group, no transplanted hepatocytes were observed. Theses preliminary results suggest that liver tissues may be regeneration by transplanting fetal hepatocytes on polymer scaffolds.

• Journal of Microbiology and Biotechnology
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• v.15 no.2
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• pp.259-264
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• 2005

Transplantation of cultured chondrocytes can regenerate cartilage tissues in cartilage defects in humans. However, this method requires a long culture period to expand chondrocytes to a large number of cells for transplantation. In addition, chondrocytes may dedifferentiate during long-term culture. These problems can potentially be overcome by the use of undifferentiated or partially developed cartilage precursor cells derived from neonatal cartilage, which, unlike chondrocytes from adult cartilage, have the capacity for rapid in vitro cell expansion and may retain their differentiated phenotype during long-term culture. The purpose of this study was to compare the cell growth rate and phenotypic modulation during in vitro culture between adult chondrocytes and neonatal chondrocytes, and to demonstrate the feasibility of regenerating cartilage tissues in vivo by transplantation of neonatal chondrocytes expanded in vitro and seeded onto polymer scaffolds. When cultured in vitro, chondrocytes isolated from neonatal (immediately postpartum, 2 h of age) rats exhibited much higher growth rate than chondrocytes isolated from adult rats. After 5 days of culture, more neonatal chondrocytes were in the differentiated state than adult chondrocytes. Cultured neonatal chondrocytes were seeded onto biodegradable polymer scaffolds and transplanted into athymic mice's subcutaneous sites. Four weeks after implantation, neonatal chondrocyte-seeded scaffolds formed white cartilaginous tissues. Histological analysis of the implants with hematoxylin and eosin showed mature and well-formed cartilage. Alcian blue/ safranin-O staining and Masson's trichrome staining indicated the presence of highly sulfated glycosarninoglycans and collagen, respectively, both of which are the major extracellular matrices of cartilage. Immunohistochemical analysis showed that the collagen was mainly type II, the major collagen type in cartilage. These results showed that neonatal chondrocytes have potential to be a cell source for cartilage tissue engineering.

• The Korean Journal of Physiology and Pharmacology
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• v.21 no.2
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• pp.153-160
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• 2017

In this study, we aim to determine the in vivo effect of human umbilical cord blood-derived multipotent stem cells (hUCB-MSCs) on neuropathic pain, using three, principal peripheral neuropathic pain models. Four weeks after hUCB-MSC transplantation, we observed significant antinociceptive effect in hUCB-MSC-transplanted rats compared to that in the vehicle-treated control. Spinal cord cells positive for c-fos, CGRP, p-ERK, p-p 38, MMP-9 and MMP 2 were significantly decreased in only CCI model of hUCB-MSCs-grafted rats, while spinal cord cells positive for CGRP, p-ERK and MMP-2 significantly decreased in SNL model of hUCB-MSCs-grafted rats and spinal cord cells positive for CGRP and MMP-2 significantly decreased in SNI model of hUCB-MSCs-grafted rats, compared to the control 4 weeks or 8weeks after transplantation (p<0.05). However, cells positive for TIMP-2, an endogenous tissue inhibitor of MMP-2, were significantly increased in SNL and SNI models of hUCB-MSCs-grafted rats. Taken together, subcutaneous injection of hUCB-MSCs may have an antinociceptive effect via modulation of pain signaling during pain signal processing within the nervous system, especially for CCI model. Thus, subcutaneous administration of hUCB-MSCs might be beneficial for improving those patients suffering from neuropathic pain by decreasing neuropathic pain activation factors, while increasing neuropathic pain inhibition factor.

• Journal of Veterinary Clinics
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• v.28 no.4
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• pp.399-402
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• 2011

In recent years, the mesenchymal stem cells (MSC) derived from various tissues have been widely tested for developing cell therapies, tissue repair and transplantation. Although there has been much interest in the immunomodulatory properties of MSC and their immunologic reactions following autologous, allogeneic and xenogenic transplantation of MSC in vivo, up to date, the expression of immunogenic markers, such as class I and II human leukocyte antigens (HLA), after differentiation of human umbilical cord blood (hUCB)-derived MSC has been poorly investigated and require extensive in vitro and in vivo testing. In this experiment, the expression of the HLA-ABC and HLA-DR on hUCB-derived MSC have been tested by immunocytochemical staining. The undifferentiated MSC were moderately stained for HLA-ABC but very weakly for HLA-DR. In order to investigate the inhibitory effect of allogeneic lymphocytes on proliferation of MSC, the MSC were cultured in the presence or absence of peripheral allogeneic lymphocytes stimulated with concanavalin A. The allogeneic lymphocytes did not significantly inhibit MSC proliferation. We conclude that hUCB-MSC expressed moderately class I HLA antigen while almost negatively class II HLA antigen. The MSC have an immunomodulatory effect which can suppress the allogeneic response of lymphocytes. These in vitro data suggest that allogeneic MSC derived from cord blood can be useful candidate for allogeneic cell therapy and transplantation without a major risk of rejection.