Effect of CD146+ SHED on bone regeneration in a mouse calvaria defect model.

OBJECTIVE: Stem cells from human exfoliated deciduous teeth (SHED) have bone regeneration ability and potential therapeutic applications. CD146, a cell adhesion protein expressed by vascular endothelial cells, is involved in osteoblastic differentiation of stem cells. The effect of CD146 on SHED-mediated bone regeneration in vivo remains unknown. We aimed to establish efficient conditions for SHED transplantation. MATERIALS AND METHODS: SHED were isolated from the pulp of an extracted deciduous tooth and cultured; CD146-positive (CD146+ ) and CD146-negative (CD146- ) populations were sorted. Heterogeneous populations of SHED and CD146+ and CD146- cells were transplanted into bone defects generated in the skulls of immunodeficient mice. Micro-computed tomography was performed immediately and 4 and 8 weeks later. Histological and immunohistochemical assessments were performed 8 weeks later. RESULTS: Bone regeneration was observed upon transplantation with CD146+ and heterogeneous populations of SHED, with significantly higher bone regeneration observed with CD146+ cells. Bone regeneration was higher in the CD146- group than in the control group, but significantly lower than that in the other transplant groups at 4 and 8 weeks. Histological and immunohistochemical assessments revealed that CD146+ cells promoted bone regeneration and angiogenesis. CONCLUSION: Transplantation of CD146+ SHED into bone defects may be useful for bone regeneration.

Bone Differentiation Ability of CD146-Positive Stem Cells from Human Exfoliated Deciduous Teeth.

Regenerative therapy for tissues by mesenchymal stem cell (MSCs) transplantation has received much attention. The cluster of differentiation (CD)146 marker, a surface-antigen of stem cells, is crucial for angiogenic and osseous differentiation abilities. Bone regeneration is accelerated by the transplantation of CD146-positive deciduous dental pulp-derived mesenchymal stem cells contained in stem cells from human exfoliated deciduous teeth (SHED) into a living donor. However, the role of CD146 in SHED remains unclear. This study aimed to compare the effects of CD146 on cell proliferative and substrate metabolic abilities in a population of SHED. SHED was isolated from deciduous teeth, and flow cytometry was used to analyze the expression of MSCs markers. Cell sorting was performed to recover the CD146-positive cell population (CD146+) and CD146-negative cell population (CD146-). CD146 + SHED without cell sorting and CD146-SHED were examined and compared among three groups. To investigate the effect of CD146 on cell proliferation ability, an analysis of cell proliferation ability was performed using BrdU assay and MTS assay. The bone differentiation ability was evaluated using an alkaline phosphatase (ALP) stain after inducing bone differentiation, and the quality of ALP protein expressed was examined. We also performed Alizarin red staining and evaluated the calcified deposits. The gene expression of ALP, bone morphogenetic protein-2 (BMP-2), and osteocalcin (OCN) was analyzed using a real-time polymerase chain reaction. There was no significant difference in cell proliferation among the three groups. The expression of ALP stain, Alizarin red stain, ALP, BMP-2, and OCN was the highest in the CD146+ group. CD146 + SHED had higher osteogenic differentiation potential compared with SHED and CD146-SHED. CD146 contained in SHED may be a valuable population of cells for bone regeneration therapy.

Stem cell-derived conditioned media from human exfoliated deciduous teeth promote bone regeneration.

OBJECTIVES: Cleft lip and palate (CL/P) are common congenital orofacial anomalies. Autogenous iliac bone grafting closes alveolar cleft defects but requires surgical intervention. Mesenchymal stem cell culture supernatant can regenerate tissues via paracrine activity. However, little is known about the bone-regenerative effects of stem cells from human exfoliated deciduous teeth (SHED) and conditioned media (CM). Our aim was to address this. MATERIALS AND METHODS: Stem cells were isolated from primary tooth pulp and cultured. Defects were made in calvariae of immunodeficient mice and implanted with stem cell- or CM-containing atelocollagen. Regenerated bone was analysed by microcomputed tomography, haematoxylin-eosin and Masson's trichrome staining. Vascular endothelial growth factor, CD31 and CD34 expression were confirmed by immunohistochemistry, and the presence of several proteins and growth factors was verified in SHED-CM. RESULTS: Bone regeneration was enhanced in defects treated with stem cells and CM compared to that in controls 8 weeks after transplantation. Mature bone formation and angiogenesis were confirmed with CM but not with stem cells or in controls. Secretome analysis using multiple cytokine assays revealed that SHED-CM contained tissue-regenerating factors with roles in angiogenesis and osteogenesis. CONCLUSION: CM non-invasively regenerate bone and might be effective to reconstruct alveolar clefts in CL/P patients.

Examination of the effect of combined use of Er:YAG laser irradiation and mechanical force loading on bone metabolism using primary human gingival fibroblasts.

Prolonged treatment and painful tooth movement are major problems for patients undergoing orthodontic treatment. Accelerating the movement of teeth leads to shortening of the treatment period, so various studies on the movement of teeth have been conducted in the field of orthodontics. In previous studies, we performed a fiber incision-like fiberotomy using an Er:YAG laser in rats and confirmed acceleration of tooth movement. Therefore, in this study, the effect of Er:YAG laser irradiation on human gingival fibroblasts was investigated in vitro. Human gingival fibroblasts (2.0 × 105 cells) were seeded in a 6-well plate and reached 80% confluence 24 h later. A control group not undergoing any irradiation and 3 groups undergoing laser irradiation at 0.6 W, 1.0 W, and 1.2 W were investigated. Laser irradiation was performed 24 h after cell seeding. The cells were then recovered 24 h later, and the cyclooxygenase-2 (COX-2), interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), bone morphogenetic protein-2 (BMP-2), and BMP-4 genes were confirmed by PCR. In addition, a control group not undergoing any procedures, a group undergoing only Er:YAG laser irradiation, a group undergoing only centrifugal loading, and a group undergoing both Er:YAG laser irradiation and centrifugal force loading were investigated. After 24 h, cells were collected and PCR was performed. Twenty-four hours after laser irradiation, gene expressions were examined by quantitative RT-PCR, which showed that the gene expressions of COX-2, IL-1ß, TNF-α, BMP-2, and BMP-4 increased depending on the amount of irradiation energy, with the largest value at 1.2 W. Gene expressions of COX-2, IL-1ß, TNF-α, BMP-2, and BMP-4 were significantly higher in the laser with centrifugal load group than in the load group. These results suggest that genes related to bone metabolism are activated in human gingival fibroblasts when mechanical stimulation and laser irradiation are combined. This helps to elucidate the effects of Er:YAG laser irradiation during tooth movement.

Stem cells derived from human exfoliated deciduous teeth-based media in a rat root resorption model.

OBJECTIVE: Root resorption may occur during orthodontic treatment. Herein, we investigated the effect of a culture supernatant of stem cells derived from human exfoliated deciduous teeth on root resorption. DESIGN: Twelve 8-week-old male Sprague-Dawley rats were used, and their maxillary first molars were pulled with excessive orthodontic force to induce root resorption. On days 1 and 7 after traction initiation, stem cells derived from human exfoliated deciduous teeth and alpha minimum essential medium (control group) were administered. After 14 days, the maxillary bone was evaluated for tooth movement. The expression of osteoprotegerin, receptor activator of nuclear factor κB ligand, tumor necrosis factor α, interleukin 1ß, interleukin 6, and interleukin 17 was evaluated on the compression side and tension side. RESULTS: No significant difference in tooth movement was observed between the two groups. Root resorption decreased in the group administered the culture supernatant compared with in the control. Immunohistochemical staining revealed increased osteoprotegerin expression and decreased receptor activators for nuclear factor κB ligand, tumor necrosis factor α, interleukin 1ß, interleukin 6, and interleukin 17 on the compression side and tension side. CONCLUSIONS: Administration of stem cells derived from human exfoliated deciduous teeth affected the expression of osteoprotegerin, receptor activator of nuclear factor κB ligand, tumor necrosis factor α, interleukin 1ß, interleukin 6 and interleukin 17; hence, these stem cells may inhibit root resorption by regulating their expression.

Effect of Er: YAG Laser Irradiation on Bone Metabolism-Related Factors Using Cultured Human Osteoblasts.

Introduction: A variety of laser treatments have been applied in numerous medical fields. In dentistry, laser treatments are used for caries, root canals, and periodontal disease, as well as surgical resection. Numerous reports have recently been published on the use of lasers for bone regeneration. If laser irradiation is found to promote the activation of bone metabolism, it might also be effective for periodontal treatment, peri-implantitis, and bone regeneration. Therefore, the present in vitro study aimed to elucidate the mechanisms underlying the effects of erbium-doped yttrium aluminum garnet (Er: YAG) laser irradiation on the bone using osteoblast-like cells. Methods: Osteoblast-like Saos 2 cells (5.0×104 cells) were seeded in 24-well plates. 24 hours after being seeded, the cells were subjected to 0.3 W, 0.6 W, and 2.0 W Er: YAG laser irradiation and then allowed to recover for 48 hours. The expression levels of bone metabolism-related factors alkaline phosphatase (ALP), bone sialoprotein (BSP), and osteoprotegerin (OPG) were then evaluated using reverse transcription-quantitative polymerase chain reaction and western blot analyses. Results: Saos 2 cells subjected to Er: YAG laser irradiation at 0.3 W, 0.6 W, and 2.0 W showed normal growth. When the Er: YAG laser irradiation and control groups were compared after 48 hours, increases were observed in ALP, BSP, and OPG gene and protein expression in the 2.0 W group. Similar results were obtained in the western blot analysis. Conclusion: These findings suggest that the Er: YAG laser irradiation of osteoblast-like cells is effective for activating bone metabolism factors.

Effects of Human Deciduous Dental Pulp-Derived Mesenchymal Stem Cell-Derived Conditioned Medium on the Metabolism of HUVECs, Osteoblasts, and BMSCs.

In this study, we assessed the effects of human deciduous dental pulp-derived mesenchymal stem cell-derived conditioned medium (SHED-CM) on the properties of various cell types. The effects of vascular endothelial growth factor (VEGF) in SHED-CM on the luminal architecture, proliferative ability, and angiogenic potential of human umbilical vein endothelial cells (HUVECs) were determined. We also investigated the effects of SHED-CM on the proliferation of human-bone-marrow mesenchymal stem cells (hBMSCs) and mouse calvarial osteoblastic cells (MC3T3-E1) as well as the expression of ALP, OCN, and RUNX2. The protein levels of ALP were examined using Western blot analysis. VEGF blockade in SHED-CM suppressed the proliferative ability and angiogenic potential of HUVECs, indicating that VEGF in SHED-CM contributes to angiogenesis. The culturing of hBMSCs and MC3T3-E1 cells with SHED-CM accelerated cell growth and enhanced mRNA expression of bone differentiation markers. The addition of SHED-CM enhanced ALP protein expression in hBMSCs and MT3T3-E1 cells compared with that of the 0% FBS group. Furthermore, SHED-CM promoted the metabolism of HUVECs, MC3T3-E1 cells, and hBMSCs. These findings indicate the potential benefits of SHED-CM in bone tissue regeneration.

Combination of Carbonate Hydroxyapatite and Stem Cells from Human Deciduous Teeth Promotes Bone Regeneration by Enhancing BMP-2, VEGF and CD31 Expression in Immunodeficient Mice.

The objective of this study was to clarify the efficiency of a combination of stem cells from human deciduous teeth and carbonate apatite in bone regeneration of calvarial defects. Immunodeficient mice (n = 5 for each group/4 groups) with artificial calvarial bone defects (5 mm in diameter) were developed, and stem cells from human deciduous teeth (SHEDs) and carbonate hydroxyapatite (CAP) granules were transplanted with an atelocollagen sponge as a scaffold. A 3D analysis using microcomputed tomography, and 12 weeks after transplantation, histological and immunohistochemical evaluations of markers of bone morphogenetic protein-2 (BMP-2), vascular endothelial growth factor (VEGF), and cluster of differentiation (CD) 31 were performed. In the 3D analysis, regenerated bone formation was observed in SHEDs and CAP, with the combination of SHEDs and CAP showing significantly greater bone regeneration than that in the other groups. Histological and immunohistochemical evaluations showed that combining SHEDs and CAP enhanced the expression of BMP-2, VEGF, and CD31, and promoted bone regeneration. This study demonstrates that the combination of SHEDs and CAP transplantation may be a promising tool for bone regeneration in alveolar defects.

Success rates in isolating mesenchymal stem cells from permanent and deciduous teeth.

Stem cells from human exfoliated deciduous teeth (SHED) and human dental pulp stem cells (hDPSCs) have emerged as attractive cell sources for bone regeneration. However, the specific teeth and the conditions most suitable for stem cell isolation remain unclear. Therefore, the success rate of SHED and hDPSCs isolation, the patient age and remaining root length in deciduous teeth were evaluated. Successful isolation was defined as when the cell culture was maintained up to the third passage without any contamination or other issues. Remaining tooth length was calculated using the root-to-crown ratio from patient X-rays and compared to the norm value from the literature. The overall successful isolation rate of SHED and hDPSCs was 82% and 70%. The average patient ages at extraction of the deciduous teeth and permanent teeth were 11 years and 9 months, and 22 years and 10 months respectively. In the successful SHED group, the average remaining root length of the anterior deciduous teeth was 71.4%, and that of the deciduous molars was 61.4%. Successful isolation appears to be associated with patient age, length of the remaining root, and also mechanical stress and other factors. Tooth selection criteria need to be identified to improve the success rate.