• Journal of dental hygiene science
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• v.13 no.3
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• pp.296-303
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• 2013

Lysyl oxidase (LOX), extracellular matrix enzyme, is catalyzing lysine-derived crosslinks in collagen and elastin. Recently, several LOX-like proteins (LOXL, LOXL2, LOXL3 and LOXL4) have been identified in human but their specific functions are still largely unknown. The purpose of this study was to evaluate the function of the LOX family genes during odontoblastic differentiation of human dental pulp (HDP) cells induced with odontogenic supplement (OS). The messenger RNA (mRNA) expression of LOX family genes and differentiation markers was assessed by reverse transcriptase polymerase chain reaction analysis (RT-PCR). The formation of mineralization nodules was evaluated by alrizarin red S staining. Amine oxidase activity of HDP cells was measured by peroxidase-coupled fluormetric assay. The expressions of differentiation markers, such as alkaline phosphatase (ALP), osteopontin (OPN), osteocalcin (OCN), dentin matrix protein1 (DMP1), dentin sialophosphoprotein (DSPP) in HDP cells were increased after treatment with OS media. The LOX and LOXL mRNA expression were gradually increased in OS media, whereas LOX enzyme activities were markedly detected on day 7. The mRNA expression and LOX enzyme activity of collagen type I was very similar to the pattern of LOX gene. In this study, the expression of LOX and its isoforms, and activity of LOX were highly regulated during odontoblastic differentiation. Thus, these results suggest that LOX plays a key role in odontoblastic differentiation of HDP cells.

• 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.

• Molecules and Cells
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• v.39 no.11
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• pp.790-796
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• 2016

Dental pulp is a highly vascularized tissue requiring adequate blood supply for successful regeneration. In this study, we investigated the functional role of stem cells from human exfoliated deciduous teeth (SHEDs) as a perivascular source for in vivo formation of vessel-like structures. Primarily isolated SHEDs showed mesenchymal stem cell (MSC)-like characteristics including the expression of surface antigens and in vitro osteogenic and adipogenic differentiation potentials. Moreover, SHEDs were positive for NG2, ${\alpha}$-smooth muscle actin (SMA), platelet-derived growth factor receptor beta ($PDGFR{\beta}$), and CD146 as pericyte markers. To prove feasibility of SHEDs as perivascular source, SHEDs were transplanted into immunodeficient mouse using Matrigel with or without human umbilical vein endothelial cells (HUVECs). Transplantation of SHEDs alone or HUVECs alone resulted in no formation of vessel-like structures with enough red blood cells. However, when SHEDs and HUVECs were transplanted together, extensive vessel-like structures were formed. The presence of murine erythrocytes within lumens suggested the formation of anastomoses between newly formed vessel-like structures in Matrigel plug and the host circulatory system. To understand underlying mechanisms of in vivo angiogenesis, the expression of angiogenic cytokine and chemokine, their receptors, and MMPs was compared between SHEDs and HUVECs. SHEDs showed higher expression of1VEGF, SDF-$1{\alpha}$, and $PDGFR{\beta}$ than HUVECs. On the contrary, HUVECs showed higher expression of VEGF receptors, CXCR4, and PDGF-BB than SHEDs. This differential expression pattern suggested reciprocal interactions between SHEDs and HUVECs and their involvement during in vivo angiogenesis. In conclusion, SHEDs could be a feasible source of perivascular cells for in vivo angiogenesis.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.4
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• pp.657-661
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• 2005

Various chemotherapeutic agents have been recommended for pulpotomy of primary teeth, and there are formocresol, ferric sulfate, and calcium hydroxide. Of those, formocresol has fixation effect of pulp tissue and high clinical success rate, so it is most commonly used agent. But formocresol has strong cytotoxic effects, thus many articles reported displacement and loss of permanent successor, amelogenesis imperfecta, mutation by general absorption, possibility of cancer induction. Recently, it has been reported that leakage by imperfect temporary sealing when FC-soaked cotton was inserted into the root canal caused necrosis of surrounding tissues. and that necrosis of alveolar bone related to the use of excessive formocresol. In this case, 2nd primary molar of upper left jaw was treated using formocresol in local clinic, but extracted because of lasting pain. Furthermore, symptoms didn't disappear so patient was refered to us. The patient was 8-year-old male, had foul odor from oral cavity and circular alveolar bone necrosis around the permanent successor' crown. Thus sequestrectomy was operated and observed through 19 months after operation, we found normal root development of permanent successor but no complete regeneration of alveolar bone defect and attached gingiva. Lesion of periodontal tissues by formocresol is irreversible, so we have to confirm the indication in using formocresol and pay attention to complete temporary sealing.

• Restorative Dentistry and Endodontics
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• v.34 no.3
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• pp.169-176
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• 2009

Diabetes Mellitus (DM) is a syndrome accompanied with the abnormal secretion or function of insulin, a hormone that plays a vital role in controlling the blood glucose level (BGL). Type land 2 DM are most common form and the prevalence of the latter is recently increasing, The aim of this article was to assess whet her Type 2 DM could act as a predisposing risk factor on the pulpo-periapical pathogenesis. Previous literature on the pathologic changes of blood vessels in DM was thoroughly reviewed. Furthermore, a histopathologic analysis of artificially-induced periapical specimens obtained from Type 2 diabetic and DM-resistant rats was compared. Histopathologic results demonstrate that the size of periapical bone destruction w as larger and the degree of pulpal inflammation was more severe in diabetic rats, indicating that Type 2 D M itself can be a predisposing risk factor that makes the host more susceptible to pulpal infection. The possible reasons may be that in diabetic state the lumen of pulpal blood vessels are thickened by atheromatous deposits, and microcirculation is hindered, The function of polymorphonuclear leukocyte is also impair ed and the migration of immune cells is blocked, leading to increased chance of pulpal infection. Also, lack of collateral circulation of pulpal blood vessels makes the pulp more susceptible to infection. These decrease the regeneration capacity of pulpal cells or tissues, delaying the healing process, Therefore, when restorative treatment is needed in Type 2 DM patients, dentists should minimize irritation to the pulpal tissue un der control of BGL.