• International Journal of Oral Biology
• /
• 제42권4호
• /
• pp.149-153
• /
• 2017

Cyclooxygenase-2 (COX-2)-mediated prostaglandin $E_2$ ($PGE_2$) plays a key role in development and progression of inflammatory responses and Porphyromonas gingivalis is a common endodontic pathogen. In this study, we investigated induction of COX-2 and $PGE_2$ by P. gingivalis in human dental pulp cells (HDPCs). P. gingivalis increased expression of COX-2, but not that of COX-1. Increased levels of $PGE_2$ were released from P. gingivalis-infected HDPCs and this $PGE_2$ increase was blocked by celecoxib, a selective COX-2 inhibitor. P. gingivalis activated all three types of mitogen-activated protein kinases (MAPKs). P. gingivalis-induced activation of nuclear $factor-{\kappa}B$ ($NF-{\kappa}B$) was demonstrated by the results of phosphorylation of $NF-{\kappa}B$ p65 and degradation of inhibitor of ${\kappa}B-{\alpha}$ ($I{\kappa}B-{\alpha}$). Pharmacological inhibition of each of the three types of MAPKs and $NF-{\kappa}B$ substantially attenuated P. gingivalis-induced $PGE_2$ production. These results suggest that P. gingivalis should promote endodontic inflammation by stimulating dental pulp cells to produce $PGE_2$.

• International Journal of Oral Biology
• /
• 제42권3호
• /
• pp.91-97
• /
• 2017

Although anti-aging activities of melatonin, a hormone secreted by the pineal gland, have been reported in senescence-accelerated mouse models and several types of cells, its impact and mechanism on the senescence of human dental pulp cells (HDPCs) remains unknown. In this study, we examined the impact of melatonin on cellular premature senescence of HDPCs. Here, we found that melatonin markedly inhibited senescent characteristics of HDPCs after exposure to hydrogen peroxide ($H_2O_2$), including the increase in senescence-associated ${\beta}$-galactosidase (SA-${\beta}$-gal)-positive HDPCs and the upregulation of p21 protein, an indicator for senescence. In addition, as melatonin attenuated $H_2O_2$-stimulated phosphorylation of c-Jun N-terminal kinase (JNK), while selective inhibition of JNK activity with SP600125 significantly attenuated $H_2O_2$-induced increase in SA-beta-gal activity. Results reveal that melatonin antagonizes premature senescence of HDPCs via JNK pathway. Thus, melatonin may have therapeutic potential to prevent stress-induced premature senescence, possibly correlated with development of dental pulp diseases, and to maintain oral health across the life span.

• International Journal of Oral Biology
• /
• 제31권3호
• /
• pp.73-79
• /
• 2006

Tissue stem cells are used for the regenerative medicine. In previous study we observed hard tissue formation of human dental pulp-derived cells using alginate scaffold. In this study, we explore the ability to differentiate of the 13th passage cells with glycerol 2-phosphate disodium salt hydrate (${\beta}-GP$) which accelerate calcification. Reverse transcriptase Polymerase Chain Reaction (RT-PCR), transplants using alginate scaffold and histological examination were performed. We observed the expression of DSPP mRNA on day 10 cultured cells with ${\beta}-GP$. In conclusion, the 13th passage cells still have an ability to differentiate into odontoblast-like cells and alginate supports the differentiation of cultured cells in the transplants.

• 대한치과의사협회지
• /
• 제16권3호통권106호
• /
• pp.193-195
• /
• 1978

The author observed the effect of x-ray irradiation on the tooth germ development of the rat fetuses. The lower right abdomen of the pregnant rats were exposed to x-ray irradiation (400 rads) on 9½th day of qestation. At 18½th day of qestation, the fetuses were removed from their mothers and histological sections of molar region were prepared. The results were as folows: 1. In the experimental fetuses, no significant changes appeared in the histological aspects of the enamel pulp, except the poor development of the innerenamel epithelium in the cusp region. 2. Pulp cells of cusp region in the irradiated fetuses were not differentiated to odontoblasts, The arrangement and population of pulp cells showed marked regional differences in the dental papilla. 3. Developmental features of dental follicle of irradiated fetuses were similar with controls.

• International Journal of Oral Biology
• /
• 제47권4호
• /
• pp.55-62
• /
• 2022

Bioactive flavonoids have been shown to improve the biological activity of stem cells derived from different sources in tissue regeneration. The goal of this study was to see how naringin, a natural flavonoid discovered in citrus fruits, affected the biological properties of human dental pulp stem cells (HDPSCs). In this study, we found that naringin increases the migratory ability of HDPSCs. Naringin increased matrix metalloproteinase-2 (MMP-2) and C-X-C chemokine receptor type 4 (CXCR4) mRNA and protein expression in HDPSCs. ARP100, a selective MMP-2 inhibitor, and AMD3100, a CXCR4 antagonist, both inhibited the naringin-induced migration of HDPSCs. Furthermore, naringin increased osteogenic differentiation of HDPSCs and the expression of the osteogenic-related marker, alkaline phosphatase in HDPSCs. Taken together, our findings suggest that naringin may be beneficial on dental tissue or bone regeneration by increasing the biological activities of HDPSCs.

• Restorative Dentistry and Endodontics
• /
• 제48권1호
• /
• pp.2.1-2.12
• /
• 2023

Objectives: In this study, natural substances were introduced as primary dental pulp caps for use in pulp therapy, and the antimicrobial and cytotoxic properties of these substances were investigated. Materials and Methods: In this in vitro study, the antimicrobial properties of calcium-enriched mixture (CEM) cement, propolis, and propolis individually combined with the extracts of several medicinal plants were investigated against Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. Then, the cytotoxicity of each substance or mixture against pulp stem cells extracted from 30 primary healthy teeth was evaluated at 4 concentrations. Data were gathered via observation, and optical density values were obtained using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) test and recorded. SPSS software version 23 was used to analyze the data. Data were evaluated using 2-way analysis of variance and the Tukey test. Results: Regarding antimicrobial properties, thyme alone and thyme + propolis had the lowest minimum inhibitory concentrations (MICs) against the growth of S. aureus, E. coli, and P. aeruginosa bacteria. For E. faecalis, thyme + propolis had the lowest MIC, followed by thyme alone. At 24 and 72 hours, thyme + propolis, CEM cement, and propolis had the greatest bioviability in the primary dental pulp stem cells, and lavender + propolis had the lowest bioviability. Conclusions: Of the studied materials, thyme + propolis showed the best results in the measures of practical performance as a dental pulp cap.

• BMB Reports
• /
• 제55권7호
• /
• pp.336-341
• /
• 2022

Narrowing of arteries supplying blood to the limbs provokes critical hindlimb ischemia (CLI). Although CLI results in irreversible sequelae, such as amputation, few therapeutic options induce the formation of new functional blood vessels. Based on the proangiogenic potentials of stem cells, in this study, it was examined whether a combination of dental pulp stem cells (DPSCs) and human umbilical vein endothelial cells (HUVECs) could result in enhanced therapeutic effects of stem cells for CLI compared with those of DPSCs or HUVECs alone. The DPSCs+ HUVECs combination therapy resulted in significantly higher blood flow and lower ischemia damage than DPSCs or HUVECs alone. The improved therapeutic effects in the DPSCs+ HUVECs group were accompanied by a significantly higher number of microvessels in the ischemic tissue than in the other groups. In vitro proliferation and tube formation assay showed that VEGF in the conditioned media of DPSCs induced proliferation and vessel-like tube formation of HUVECs. Altogether, our results demonstrated that the combination of DPSCs and HUVECs had significantly better therapeutic effects on CLI via VEGF-mediated crosstalk. This combinational strategy could be used to develop novel clinical protocols for CLI proangiogenic regenerative treatments.

• Restorative Dentistry and Endodontics
• /
• 제31권3호
• /
• pp.203-214
• /
• 2006

치수는 상아질로 둘러싸인 간엽조직으로 다양한 세포와 기저 물질들로 구성되어 있으며 혈관과 신경조직이 분포되어 있다. 치수의 염증은 조직의 분해를 야기하며 이는 Matrix Metalloproteinase에 의해 세포 외 기질의 분해가 촉진되어 병적인 과정을 거치게 된다. 이에 Lipopolysaccharide에 의한 MMP와 inflammatory cytokine의 유도와 peroxisome proliferator-activated receptors (PPAR)에 의한 염증매개 물질의 조절에 대해 알아보고자 하였다. 사람의 치수세포를 다양한 LPS농도에 노출시킨 후 24시간째 MMP-2, MMP-9의 변화를 보고 LPS에 의해 자극된 치수세포에서 ICAM-1, VCAM-1, $IL-1{\beta},\;TNF-{\alpha}$의 분비가 증가됨을 알 수 있었다. 또한 Adenovirus $PPAR{\gamma}\;(Ad/PPAR{\gamma})$와 $PPAR{\gamma}$ agonist인 rosiglitazone를 LPS로 자극된 치수세포에 처리하였을 때 48시간째 MMPs와 Adhesion molecules, cytokines의 감소를 확인하였다. 이로써 사람의 치수세포에서 $PPAR{\gamma}$가 가지는 항 염증효과에 대해 지속적 인 연구가 필요할 것으로 사료된다.

• 한국동물생명공학회지
• /
• 제39권2호
• /
• pp.95-104
• /
• 2024

Background: In healthy dentin conditions, odontoblasts have an important role such as protection from invasion of pathogens. In mammalian teeth, progenitors such as mesenchymal stem cells (MSCs) can migrate and differentiate into odontoblast-like cells, leading to the formation of reparative dentin. For differentiation using stem cells, it is crucial to provide conditions similar to the complex and intricate in vivo environment. The purpose of this study was to evaluate the potential of differentiation into odonto/osteoblasts, and compare co-culture with/without epithelial cells. Methods: MSCs and epithelial cells were successfully isolated from dental tissues. We investigated the influences of epithelial cells on the differentiation process of dental pulp stem cells into odonto/osteoblasts using co-culture systems. The differentiation potential with/without epithelial cells was analyzed for the expression of specific markers and calcium contents. Results: Differentiated odonto/osteoblast derived from dental pulp tissue-derived mesenchymal stem cells with/without epithelial cells were evaluated by qRT-PCR, immunostaining, calcium content, and ALP staining. The expression of odonto/osteoblast-specific markers, calcium content, and ALP staining intensity were significantly increased in differentiated cells. Moreover, the odonto/osteogenic differentiation capacity with epithelial cells co-culture was significantly higher than without epithelial cells co-culture. Conclusions: These results suggest that odonto/osteogenic differentiation co-cultured with epithelial cells has a more efficient application.

• 구강회복응용과학지
• /
• 제25권2호
• /
• pp.191-200
• /
• 2009

줄기세포는 미분화 상태의 세포로 지속적인 자가 분열능과 특정 세포로 분화 할 수 있는 분화능을 지니고 있으며 이러한 특성으로 말미암아 난치병의 새로운 장을 열 것이라는 기대감을 얻고 있다. 즉, 세포이식 후 특정 세포로 분화 유도를 시켜 기존의 치료 방법으로는 치료가 되지 않았던 많은 의학적 난제들을 풀 수 있는 열쇠인 것이다. 치아는 평생에 걸쳐 발거되는 조직으로 치아줄기세포는 얻기가 비교적 쉬워서 다른 성체줄기세포들보다 더 높이 평가되고 있다. 과잉치는 전 세계 다양한 인종에서 발견되는 중요한 임상적 질환이다. 과잉치의 유병율은 관련 연구 보고서마다 다양하나 소아치과 의사들의 경우 임상에서 자주 과잉치를 발거하고 있다. 그러나, 현재까지 진행된 줄기세포 관련 연구들을 살펴보면 과잉치의 줄기세포에 관한 보고는 없으며, 이는 줄기세포로 이용 가능한 중요한 자원을 파기하고 있는 것은 아닌지 의문이 생긴다. 그러므로 본 연구는 과잉치에 포함된 세포가 줄기세포의 특징을 가지고 있는지를 밝혀내기 위해 진행되었다.