• 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.

• Journal of Periodontal and Implant Science
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• v.41 no.4
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• pp.192-200
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• 2011

Purpose: The aim of this study is to compare the gene expression profile in mesenchymal stem cells derived from dental tissues and bone marrow for characterization of dental stem cells. Methods: We employed GeneChip analysis to the expression levels of approximately 32,321 kinds of transcripts in 5 samples of bone-marrow-derived mesenchymal stem cells (BMSCs) (n=1), periodontal ligament stem cells (PDLSCs) (n=2), and dental pulp stem cells (DPSCs) (n=2). Each cell was sorted by a FACS Vantage Sorter using immunocytochemical staining of the early mesenchymal stem cell surface marker STRO-1 before the microarray analysis. Results: We identified 379 up-regulated and 133 down-regulated transcripts in BMSCs, 68 up-regulated and 64 down-regulated transcripts in PDLSCs, and 218 up-regulated and 231 down-regulated transcripts in DPSCs. In addition, anatomical structure development and anatomical structure morphogenesis gene ontology (GO) terms were over-represented in all three different mesenchymal stem cells and GO terms related to blood vessels, and neurons were over-represented only in DPSCs. Conclusions: This study demonstrated the genome-wide gene expression patterns of STRO-$1^+$ mesenchymal stem cells derived from dental tissues and bone marrow. The differences among the expression profiles of BMSCs, PDLSCs, and DPSCs were shown, and 999 candidate genes were found to be definitely up- or down-regulated. In addition, GOstat analyses of regulated gene products provided over-represented GO classes. These data provide a first step for discovering molecules key to the characteristics of dental stem cells.

• Korean Journal of Veterinary Research
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• v.16 no.1
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• pp.97-103
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• 1976

In order to clarify the histopathological changes resulting from nitrate poisoning, rabbits were experimentally poisoned by the oral administration of $KNO_3$ or $NaNO_2$ and examined clinically and histopathologically. In addition, the quantitative changes of glycogen level in hepatic cells were histochemically observed. The results obtained were summarized as follows: 1. Clinical symptoms observed from the acute cases which died within 2 hours after the administration were severe cyanosis of visible mucosa, frequent urination, and dyspnea. However, in chronic cases administrated daily with $KNO_3$ for 43, 50 and 74 days respectively, no marked symptoms were observed. 2. Macroscopic changes observed in acute cases were severe methemoglobinemia, cloudy swelling of hepatic cells, hemorrhage and hyperemia of gastric mucosa, and hyperemia of other organs. In chronic cases there were marked hyperemia, dark-red coloring and increasing of consistency in liver and kidney, and swelling of spleen. 3. Microscopic changes observed in acute cases were hemorrhage and hyperemia of various organs, cloudy swelling and centrilobular necrosis of hepatic cells and necrosis of convoluted tubular epithelium in kidney. In chronic cases there were round cell infiltration of the interlobular connective tissue and epithelial proliferation of interlobular bile ducts in the liver, and necrosis of the convoluted tubular epithelium and proliferation of interstitial connective tissue in kidney, thickening of alveolar septa of lungs, activated hemopoiesis of bone marrow, and myeloid metaplasia of sqlenic pulp. 4. Glycogen storage in liver cells was decreased in acute cases, on the contrary, increased in chronic cases.

• Korean Journal of Veterinary Research
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• v.48 no.2
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• pp.197-201
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• 2008

Plasmodium spp. in domestic and wild birds are microscopic, intracellular parasitic protozoa within the blood cells and tissues cause avian malaria. A 17-month-old Magellan penguin (Spheniscus magellanicus) with a clinical signs of anorexia, depression, and respiratory distress for 3 days was submitted to the Pathology Department of Veterinary Medicine, Cheju National University in October 2005. It was born and reared in the Jeju Island. Grossly, the liver was enlarged, pale and friable. The spleen was also enlarged with dark red coloration and friable. Histopathologically, the lesions in the liver were characterized by multifocal infiltration of macrophages and lymphocytes especially in perivascular regions. The schizonts of Plasmodium spp. contained up to 30 merozoites were found in numerous infiltrated mononuclear cells. Similarly, histiocytic cells were proliferated in red pulp of spleen and the schizonts were found in these cells. Numerous dark brown pigments were widely distributed in the liver and spleen. The result of the nested polymerase chain reaction clarified the causative agent of this case was Plasmodium spp.. This is the first report for the outbreak of avian malaria caused by Plasmodium spp. in a penguin that was born and reared in Jeju Island in Korea.

• International Journal of Oral Biology
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• v.33 no.4
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• pp.131-135
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• 2008

Substance P (SP) is known to be expressed in the nerve fibers of dental pulp and periodontal tissues. It was recently reported that SP expression increased in response to orthodontic force. In the present study, we investigated the effect of SP on expression of mineralization markers and heme oxygenase-1 (HO-1) in human immortalized periodontal ligament (IPDL) cells. Cell viability was measured using a 3,4,5-dimethylthiazol-2-yl-2,5-diphenyl tetrazolium bromide (MTT) assay. The expression of mineralization markers, including alkaline phosphatase (ALP), osteonectin (ON) and bone sialoprotein (BSP), and heme oxygenase-1 (HO-1) was assessed by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis. SP did not significantly change human IPDL cell viability, with the exception of the 24 hour treatment group. Treatment of human IPDL cells with $10^{-10}$ to $10^{-4}M$ SP upregulated mineralization marker and HO-1 expression in a time- and concentration-dependent manner. Our results suggest that SP may modulate osteoblastic cell differentiation of human IPDL cells through a mechanism involving HO-1 expression.

• Journal of Biosystems Engineering
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• v.32 no.1 s.120
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• pp.50-56
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• 2007

Highly porous composite bioceramic bone scaffolds were developed using sintered gnotobiotic pig bones. These scaffolds consisted of poly-D,L-lactic acid (P(D,L)LA) and bioceramic materials of pig bone powder. The bone scaffolds were able to promote biocompatibility and possess interconnected pores that would support cell adhesion and proliferation adequately. The composite scaffolds were tested with dental pulp stem cells for cytotoxicity test. Cells seeded on the composite scaffolds were readily attached, well proliferated, as confirmed by cytotoxicity test, and cell adhesion assessment. The composite bone scaffold had no toxicity in cytotoxicity test on the extract of 0.013 g scaffold to 2 ml culture medium. The cells on the composite bone scaffold proliferated better than cells on the P(D,L)LA scaffolds.

• Journal of dental hygiene science
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• v.13 no.3
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• pp.321-329
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• 2013

Although it has been reported that lysyl oxidase (LOX) is involved in odontoblastic differentiation, the role of LOX on odontoblastic differentiation by hydrogen peroxide ($H_2O_2$) have not been clarified. In the present study, we investigated whether $H_2O_2$, reactive oxygen species (ROS), is modulated the messenger RNA (mRNA) expression and activity of LOX during odontoblastic differentiation of human dental pulp (HDP) cells. The mRNA expression was quantified by reverse transcriptase polymerase chain reaction (RT-PCR) analysis, and LOX enzyme activity was measured by high sensitive fluorescent assay. Expression of the odontoblastic differentiation marker genes were assessed in the presence and absence of specific small interfering RNAs (siRNAs) of the LOX and LOXL. The $H_2O_2$-induced mRNA expression of LOX family was significant reduction of LOX, LOXL, and LOXL3 mRNA levels in HDP cells. LOX enzyme activity was increased at $H_2O_2$ 0.3 mM for 24 hours. The mRNA expression of alkaline phosphatase (ALP), osteopontin (OPN), and osteocalcin (OCN) was inhibited by LOX- and LOXL-specific siRNAs whereas the mRNA expression of dentin matrix protein1 (DMP1), and dentin sialophosphoprotein (DSPP) was inhibited by LOX-specific siRNA. In LOX enzyme activity, siRNA-induced knockdown of both LOX and LOXL inhibited the total amine oxidase activity in HDP cells, as in the case of mRNA expression. In conclusion, the essential role of $H_2O_2$ on odontoblastic differentiation suggests that its regulation by LOX may have pharmacologic importance in HDP cells.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.1
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• pp.151-160
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• 2000

The effect of concentration as factor in cytotoxicity, protein synthesis and alkaline phosphatase activity was compared for pulpotomy medicaments (formaldehyde, formocresol, paraformaldehyde, ferric sulfate) Human pulp fibroblasts were exposed to a range of concentrations(0.01, 0.05, 0.10, 0.25, 0.50, $1.00{\mu}l/ml$) of each agents, for period of 24hrs. The cell activities were evaluated by MTT assay, protein assay and alkaline phosphatase activity examination. The results as follows : 1. After 24hrs culture, pulp fibroblasts adding formaldehyde, formocresol and paraformaldehyde were suppressed cell activities with concentration increasing, but, no depression of cell activities by ferric sulfate. No significant difference was in formaldehyde, formocresol and paraformaldehyde. 2. Protein synthesis by pulpotomy agents were not significant difference in pulp fibroblasts but protein synthesis were a little decreased by paraformaldehyde. 3. Alkaline phosphatase activity was a little decreased by pulpotomy medicaments.

• The Journal of the Korean dental association
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• v.51 no.10
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• pp.542-550
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• 2013

The immature teeth with apical periodontitis present considerable challenges to clinicians. Therefore, new treatment protocols have been suggested to overcome the problems encountered in traditional methods. Regenerative treatment (revascularization) is one of such methods. Many case reports on the revascularization of infected immature teeth have been published, and in most of them, immature teeth with even a periapical abscess continued root formation after the disinfection of the root canal system. We now believe that this continued root formation is not an exceptional incident. As a result, it appeared that apexification has been giving way to a revascularization technique, which is a new option, in treating necrotic immature teeth. These new methods appear to be based on the healing potential of stem cells. The potential of healing or regeneration of stem cells, which are located around teeth, seems to be greater than we thought before. This review summarizes the current techniques for considering regenerative endodontic treatment procedures in treating the immature permanent tooth with pulp necrosis.

• Proceedings of the KACD Conference
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• 2003.11a
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• pp.558-559
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• 2003

Heme oxygenase(HO) is a microsomal enzyme, widely distributed in mammalian tissues, which has a major role in heme metabolism. The role of HO in different tissues has not, as yet, been fully characterized, but it is becoming evident that it is involved in a variety of cellular regulatory and protective mechanism. Therefore, in this report, we confirmed the idea of whether the presence of HO in human pulpal cell, and HO can be a principal mechanism of nitric oxide(NO) mediated pulpal cell damage, by adding a deprivation of NO and to gain clinical relationship. We also accessed the effects of HO in pulpal cells treated with hydrogen.(omitted)