• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.1
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• pp.42-45
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• 2002

Cultures of primary human alveolar bone-derived cells were established from alveolar bone chips obtained from normal individuals undergoing tooth extraction. These cells were expanded in vitro until passage 3 and used for the in vivo assays. Cells were loaded into transplantation vehicles, and transplanted subcutaneously into immunodeficient mice to study the capacities of human alveolar bone-derived cells to form bone in vivo. Transplants were harvested 12 weeks after transplantation and evaluated histologically. Of 10 human alveolar bone-derived cell transplants, two formed a bone-like tissue that featured osteocytes and mineral. Eight of the ten formed no osseous tissue. These results show that cells from normal human alveolar bone are capable of forming bone-like tissue when transplanted into immunodeficient mice.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.2
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• pp.133-141
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• 2008

Stem cells have self-renewal capacity, long-term viability, and multiline age potential. Adult bone marrow contains mesenchymal stem cells. Bone marrow-derived mesenchymal stem cells (BMSCs) are progenitors of skeletal tissue components and can differentiate into adipocytes, chondrocytes, osteoblasts, and myoblasts in vitro and undergo differentiation in vivo. However, the clinical use of BMSCs has presented problems, including pain, morbidity, and low cell number upon harvest. Recent studies have identified a putative stem cell population within the adipose tissue. Human adipose tissue contains pluripotent stem cells simillar to bone marrow-derived stem cells that can differentiate toward the osteogenic, adipogenic, myogenic, and chondrogenic lineages. Human adipose tissue-derived stem cells (ATSCs) could be proposed as an alternative source of adult bone marrow stem cells, and could be obtained in large quantities, under local anesthesia, with minimal discomfort. Human adipose tissue obtained by liposuction was processed to obtain ATSCs. In this study, we compared the osteogenic differentiation of ATSCs in a specific osteogenic induction medium with that in a non-osteogenic medium. ATSCs were incubated in an osteogenic medium for 28 days to induce osteogenesis respectively. Osteogenic differentiation was assessed by von Kossa and alkaline phosphatase staining. Expression of osteocyte specific bone sialoprotein, osteocalcin, collagen type I and alkaline phosphatase, bone morphogenic protein 2, bone morphogenic protein 6 was confirmed by RT-PCR. ATSCs incubated in the osteogenic medium were stained positively for von Kossa and alkaline phosphatase staining. Expression of osteocyte specific genes was also detected. Since this cell population can be easily identified through fluorescence microscopy, it may be an ideal source of ATSCs for further experiments on stem cell biology and tissue engineering. The present results show that ADSCs have an ability to differentiate into osteoblasts. In the present study, we extend this approach to characterize adipose tissue-derived stem cells.

• Archives of Plastic Surgery
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• v.38 no.4
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• pp.438-444
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• 2011

Purpose: Adipose-derived stromal cells (ASCs) are readily harvested from lipoaspirated tissue or subcutaneous adipose tissue fragments. The stromal vascular fraction (SVF) is a heterogeneous set of cell populations that surround and support adipose tissue, which includes the stromal cells, ASCs, that have the ability to differentiate into cells of several lineages and contains cells from the microvasculature. The mechanisms that drive the ASCs into the osteoblast lineage are still not clear, but the process has been more extensively studied in bone marrow stromal cells. The purpose of this study was to investigate the osteogenic capacity of adipose derived SVF cells and evaluate bone formation following implantation of SVF cells into the bone defect of human phalanx. Methods: Case 1 a 43-year-old male was wounded while using a press machine. After first operation, segmental bone defects of the left 3rd and 4th middle phalanx occurred. At first we injected the SVF cells combined with demineralized bone matrix (DBM) to defected 4th middle phalangeal bone lesion. We used P (L/DL)LA [Poly (70L-lactide-co-30DL-lactide) Co Polymer P (L/DL)LA] as a scaffold. Next, we implanted the SVF cells combined with DBM to repair left 3rd middle phalangeal bone defect in sequence. Case 2 was a 25-year-old man with crushing hand injury. Three months after the previous surgery, we implanted the SVF cells combined with DBM to restore right 3rd middle phalangeal bone defect by syringe injection. Radiographic images were taken at follow-up hospital visits and evaluated radiographically by means of computerized analysis of digital images. Results: The phalangeal bone defect was treated with autologous SVF cells isolated and applied in a single operative procedure in combination with DBM. The SVF cells were supported in place with mechanical fixation with a resorbable macroporous sheets acting as a soft tissue barrier. The radiographic appearance of the defect revealed a restoration to average bone density and stable position of pharyngeal bone. Densitometric evaluations for digital X-ray revealed improved bone densities in two cases with pharyngeal bone defects, that is, 65.2% for 4th finger of the case 1, 60.5% for 3rd finger of the case 1 and 60.1% for the case 2. Conclusion: This study demonstrated that adipose derived stromal vascular fraction cells have osteogenic potential in two clinical case studies. Thus, these reports show that cells from the SVF cells have potential in many areas of clinical cell therapy and regenerative medicine, albeit a lot of work is yet to be done.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.5
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• pp.453-456
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• 2001

Background: Autogenous alveolar bone cell transplantation may be suitable for tissue engineering for alveolar bone reconstruction. This study aimed to isolate human alveolar bone-derived cells (HABDCs) and to evaluate the ability of collagen gels to support HABDC proliferation and differentiation for human alveolar bone tissue engineering applications. Method: Cultures of primary HABDCs were established from alveolar bone chips obtained from 10 persons undergoing tooth extraction. These cells were expanded in vitro until passage 3 and used for the in vitro characterization of HABDCs and the in vitro analysis of collagen gels for alveolar bone tissue engineering. Results: Of the 10 attempts made to obtain HABDC cultures, eight were successful. HABDCs expressed the osteoblastic phenotype characterized by alkaline phosphatase activity, osteocalcin expression and the mineralization of the extracellular matrix in vitro. When seeded on collagen gels, HABDCs penetrated into the collagen gel matrices and proliferated inside the gels. Significantly, when HABDCs were embedded into the gels, collagen fibers and mineralization were produced within the gels. Conclusion: This study demonstrates the feasibility of using cultured HABDCs and collagen gels for human alveolar bone tissue engineering applications.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.39 no.2
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• pp.55-62
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• 2013

Bone tissue engineering is one of the important therapeutic approaches to the regeneration of bones in the entire field of regeneration medicine. Mesenchymal stem cells (MSCs) are actively discussed as material for bone tissue engineering due to their ability to differentiate into autologous bone. MSCs are able to differentiate into different lineages: osteo/odontogenic, adipogenic, and neurogenic. The tissue of origin for MSCs defines them as bone marrow-derived stem cells, adipose tissue-derived stem cells, and, among many others, dental stem cells. According to the tissue of origin, DSCs are further stratified into dental pulp stem cells, periodontal ligament stem cells, stem cells from apical papilla, stem cells from human exfoliated deciduous teeth, dental follicle precursor cells, and dental papilla cells. There are numerous in vitro/in vivo reports suggesting successful mineralization potential or osteo/odontogenic ability of MSCs. Still, there is further need for the optimization of MSCs-based tissue engineering methods, and the introduction of genes related to osteo/odontogenic differentiation into MSCs might aid in the process. In this review, articles that reported enhanced osteo/odontogenic differentiation with gene introduction into MSCs will be discussed to provide a background for successful bone tissue engineering using MSCs with artificially introduced genes.

• International Journal of Stem Cells
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• v.16 no.1
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• pp.93-107
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• 2023

Background and Objectives: Chronic periodontitis can lead to alveolar bone resorption and eventually tooth loss. Stem cells from exfoliated deciduous teeth (SHED) are appropriate bone regeneration seed cells. To track the survival, migration, and differentiation of the transplanted SHED, we used super paramagnetic iron oxide particles (SPIO) Molday ION Rhodamine-B (MIRB) to label and monitor the transplanted cells while repairing periodontal bone defects. Methods and Results: We determined an appropriate dose of MIRB for labeling SHED by examining the growth and osteogenic differentiation of labeled SHED. Finally, SHED was labeled with 25 ㎍ Fe/ml MIRB before being transplanted into rats. Magnetic resonance imaging was used to track SHED survival and migration in vivo due to a low-intensity signal artifact caused by MIRB. HE and immunohistochemical analyses revealed that both MIRB-labeled and unlabeled SHED could promote periodontal bone regeneration. The colocalization of hNUC and MIRB demonstrated that SHED transplanted into rats could survive in vivo. Furthermore, some MIRB-positive cells expressed the osteoblast and osteocyte markers OCN and DMP1, respectively. Enzyme-linked immunosorbent assay revealed that SHED could secrete protein factors, such as IGF-1, OCN, ALP, IL-4, VEGF, and bFGF, which promote bone regeneration. Immunofluorescence staining revealed that the transplanted SHED was surrounded by a large number of host-derived Runx2- and Col II-positive cells that played important roles in the bone healing process. Conclusions: SHED could promote periodontal bone regeneration in rats, and the survival of SHED could be tracked in vivo by labeling them with MIRB. SHED are likely to promote bone healing through both direct differentiation and paracrine mechanisms.

• Journal of Periodontal and Implant Science
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• v.25 no.2
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• pp.438-457
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• 1995

The origin of fibroblasts, their proliferative activity and roles in the early stages of periodontal regeneration were investigated in order to better understand the periodontal healing process in furcation defects of the beagle dog after guided tissue regeneration. Newly divided cells were identified and quantitated by immunolocalization of bromodeoxyuridine (BrdU) injected 1 hour prior to sacrificing the animals. The results were as follows :1. During periodontal healing in horizontal furcation defect, three different stages, namely the granulation tissue, connective tissue, and bone formation stages, were identified on the basis of major types of cells and tissue. 2. In the early stages of periodontal regeneration, both the remaining periodontal ligament and alveolar bone compartment were the major sources. 3. The majority of BrdU-labeled fibroblasts were located at the following areas ; 1) the coronal zone of the defect in case of the connective tissue fanned on the root surface. 2) the area within an 400 ${\mu}m$ distance from the remaining bone level in case of the periodontal ligament. 3) the area within an 100 ${\mu}m$ distance from the bone surface in case of areas of active bone formation.4. The highly proliferative fibroblasts adjacent to bone surface played a major role in the formation of osteoblast precursor cells, whereas both paravascular and endosteal cells played a minor role in new bone formation, In conclusion, it was suggested that the fibroblasts in the remaining periodontal ligament and bone will play a major role in periodontal regeneration, whereas both paravascular and endosteal cells will play a minor role in new bone formation.

• Restorative Dentistry and Endodontics
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• v.20 no.2
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• pp.744-757
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• 1995

Implantation of demineralized bone matrices was done into the amputated pulp in vivo and sequential reaction of the pulpal ectomesenchymal cells was observed. The bone matrices, obtained from cat long bone were crushed into below $700{\mu}m$, demineralized with 0.5N HCl and allografted into pulp of molar teeth. At seven days after implantation many undifferentiated mesenchymal cells aggregated near the matrices in the pulpal tissue. At fourteen days after implantation, the cells differentiated into preosteoblast-like cells which have secretory cell characteristics. At one or two months after implantation osteoid tissue was formed. The cells, which are located at the surface of the tissue, contained abundant dilated rough endoplasmic reticulum, Golgi apparatus and secretory granules in the cytoplasm. The matrix of the tissue has less collagen fibers than those in normal dentin. These results suggest that the interaction of pulpal mesenchymal cells with demineralized bone matrix can be a model which induces mineralization.

• Biomaterials and Biomechanics in Bioengineering
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• v.1 no.3
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• pp.151-162
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• 2014

Genetically-modified mesenchymal stem cells (GM-MSCs) have emerged as promising therapeutic tools for orthopedic degenerative diseases. GM-MSCs have been widely reported that they are able to increase bone and cartilage tissue regeneration not only by secreting transgene products such as growth factors in a long-term manner, also by inducing MSCs into tissue-specific cells. For example, MSCs modified with BMP-2 gene increased secretion of BMP-2 protein resulting in enhancement of bone regeneration, while MSCs with TGF-b gene did cartilage regeneration. In this review, we introduce several growth factors for gene delivery to MSCs and strategies for bone and cartilage tissue regeneration using GM-MSCs. Furthermore, we describe strategies for strengthening GM-MSCs to more intensively induce tissue regeneration by co-delivery system of multiple genes.

• Journal of Yeungnam Medical Science
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• v.20 no.2
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• pp.142-151
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• 2003

To induce bone formation at ectopic site by tissue engineering and gene therapy, we transplanted collagen sponges containing rhBMP-7 transduced HEK 293 cells in the hypodermis of nude mice. Bone formation was investigated by histological and electron microscopic method at 3, 6, and 9 weeks after transplantation. At 9 weeks after transplantation, eosinophilic bony tissue was observed in the implanted collagen sponge and was confirmed as bone tissue by Von Kossa stain. In the transmission electron microscopic observation, the cells in newly formed bone tissue had eccentrically located nucleus and well developed rough endoplasmic reticulum (rER). Therefore, the cells were evaluated as osteoblasts. Those results suggest that it is possible to form a bone tissue in the ectopic site by transplantation of rhBMP-7 transduced HEK 293 cells. This will be contributed to push more advanced gene therapy for bone formation. However, the HEK 293 cell is unable to apply to the clinical gene therapy. Therefore it is worth to find more compatible cells for clinical application. In addition, collagen sponge is considered as an excellent scaffold and/or carrier for gene therapy and a good biomaterial for tissue engineering.