Dental erosion caused by glucocorticoid therapy in a patient with optic neuritis: a case report.

Dental erosion is characterized by progressively destroyed teeth, which has no relation to bacteria but to chemicals. Some internal factors, such as gastroesophageal reflux induced by bulimia, anorexia, gastrointestinal diseases, or drugs, and external factors, such as diet, drugs, and occupational acid exposure, are considered promotive factors for this disease. This article presents a patient suffering from severe dental erosion in the whole dentition, especially in the maxillary teeth, due to gastroesophageal reflux induced by glucocorticoid therapy for optic neuritis. This article discusses the mechanism between optic neuritis glucocorticoid therapy and dental erosion.

Platelet-rich plasma enhanced umbilical cord mesenchymal stem cells-based bone tissue regeneration.

OBJECTIVES: To evaluate the effects of platelet-rich plasma (PRP) on the proliferation and differentiation of umbilical cord mesenchymal stem cells (UC-MSCs) and explore the possibility that PRP combined with UC-MSCs may be useful for bone tissue regeneration in vivo. METHODS: The proliferation potential of UC-MSCs was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The pluripotent differentiation capacity and alkaline phosphatase (ALP) expression were further determined by ALP staining. The expression of osteoblast-associated genes was evaluated by real-time PCR. In addition, rat critical-sized calvarial defects were examined to evaluate bone regeneration in vivo. RESULTS: PRP enhanced UC-MSC proliferation, and 10% PRP caused the strongest ALP and Alizarin red staining. At 7 days, the expression levels of ALP, Collagen 1 (COL-1) and Runt-related transcription factor 2 (RUNX2) in the PRP group were higher than those in the FBS group. Newly regenerated bone was observed in the defect areas, and PRP combined with UC-MSCs can accelerate bone regeneration at an early stage. CONCLUSIONS: Our current data suggest that UC-MSCs may be utilized in alternative stem cell-based approaches for the reconstruction and regeneration of bone defects, and PRP combined with UC-MSCs can enhance bone regeneration in vivo.

Hyperlipidemia compromises homing efficiency of systemically transplanted BMSCs and inhibits bone regeneration.

PURPOSE: Mesenchymal stem cells (MSCs) can selectively home to bone defects and play an essential role in promoting bone regeneration. As an adverse effect factor for bone metabolism, hyperlipidemia significantly impairs bone regeneration. In this study, bone marrow stromal cells (BMSCs) were systemically transplanted into a hyperlipidemic mouse model to explore the effect of hyperlipidemia on stem cell recruitment and bone regeneration. METHODS: Hyperlipidemia was established in ApoE-/- mice (on C57BL/6J background) fed with a high fat diet (HFD) for five weeks. C57BL/6 mice fed with the same diet served as controls. BMSCs labeled with the green fluorescent protein (GFP) were then injected via the tail vein and bone defects were created in the mandibles. The animals were sacrificed at weeks 1, 2 and 4 after surgery, and the fate of the transplanted BMSCs was monitored with a fluorescence microscope and immunohistochemical analysis. After hematoxylin and eosin (HE) staining and Masson's Trichrome (MT) staining, histomorphometric analysis was performed to evaluate bone regeneration. RESULTS: In both groups transplanted with BMSCs, the number of GFP-positive BMSCs detected in the bone defects reached its peak at 1 week after surgery and was decreased thereafter. However, at all time points, less GFP+ cells were detected in the ApoE-/- mice than in the corresponding control mice. BMSCs transplantation significantly enhanced new bone formation, but to a lesser degree in the ApoE-/- mice when compared with the control mice. CONCLUSIONS: Hyperlipidemia compromises homing efficiency of systemically transplanted BMSCs and inhibits bone regeneration.

Osteopromotive activity of a novel pyrazole carboxamide derivative.

AIMS: To investigate the effect of 1-(4-(tert-butyl)benzyl)-N-(4-methoxyphenyl)-3-phenyl-1H-pyrazole-5-carboxamide (Pyr-C) on the proliferation and osteogenic differentiation of MC3T3-E1 cells. MATERIALS & METHODS: MTT and BrdU incorporation assay were used to determine cell survival and proliferation. The gene expression levels of osteogenic markers were determined using real-time PCR and ALP activity was detected. Western-blot analysis was used to determine the protein expression of BSP and OPN. The long-term effect of Pyr-C on mineralization deposition was measured by Alizarin Red Staining. RESULTS: Pyr-C inhibited cell proliferation and increased ALP activity. Gene expression of ALP, BSP, OCN, Runx2, and Osterix was up-regulated in Pyr-C-induced group. Pyr-C increased the protein expression of BSP at day 7, 14 and 21, and OPN at day 14, 21 and 28. Meanwhile, Pyr-C enhanced the mineral deposition. CONCLUSION: Pyr-C inhibits proliferation and stimulates osteogenic differentiation of MC3T3-E1 cells.

Superior osteogenic capacity of different mesenchymal stem cells for bone tissue engineering.

OBJECTIVE: We evaluated the effect of human bone marrow stromal cells (hBMSCs), human adipose tissue-derived mesenchymal stem cells (hAD-MSCs), and umbilical cord-derived mesenchymal stem cells (hUC-MSCs) in bone tissue engineering and identified a reliable cell source. STUDY DESIGN: Alkaline phosphatase (ALP) activity and quantitative polymerase chain reaction were used to evaluate osteogenic in vitro, X-ray and histologic analysis in vivo. RESULTS: hBMSCs exhibited strongest ALP staining, followed by hAD-MSCs and hUC-MSCs. At 7 days, hUC-MSCs and hAD-MSCs had higher expression of collagen type I and Runt-related transcription factor 2 than hBMSCs, and hUC-MSCs showed higher osteopontin expression. Bone structure was observed in the hUC-MSC group. Defects showed good healing in the hBMSC and hAD-MSC groups. Enhanced green fluorescent protein and osteopontin were detected in newly formed bone at 8 weeks. CONCLUSIONS: Our results suggested that hUC-MSCs and hAD-MSCs could be used for bone tissue engineering effectively; hUC-MSCs could serve as a new alternative cell source.

The role of systemically delivered bone marrow-derived mesenchymal stem cells in the regeneration of periodontal tissues.

PURPOSE: Recent studies have shown that periodontal ligament stem cells (PDLSCs) play a key role in periodontal regeneration. However, the origin of these cells remains unclear. Meanwhile, bone marrow is thought to be the most common source of adult stem cells in many tissues and organs. Thus, the present investigation sought to determine whether systemically delivered bone marrow-derived mesenchymal stem cells (BM-MSCs) could participate in periodontal regeneration and differentiate into periodontal-specific cells and to explore the origin of PDLSCs. METHODS: Enhanced green fluorescent protein (EGFP)-labeled BMMSCs were delivered into lethally irradiated rats by intra-bone marrow (IBM) transplantation. Four weeks after transplantation, periodontal defects with and without infection of anaerobic cultured Porphyromonas gingivalis were established. The animals were killed 1, 2, 4, or 6 weeks after periodontal defect surgery. Histomorphologic analysis, direct observation with the fluorescence microscope, and immunohistochemical staining were performed to evaluate the localization and differentiation of BM-MSCs. RESULTS: EGFP-positive BM-MSCs could be observed as early as 1 week after surgery, and the number of EGFP-positive cells reached a maximum at 2 weeks. Meanwhile, EGFP-positive cells were observed in the newly formed bone, PDL, and cementum 4 weeks after surgery. Immunohistochemical staining verified that EGFP-positive BM-MSCs could differentiate into osteoblasts. CONCLUSIONS: These findings provide direct evidence that BM-MSCs can participate in and modulate periodontal regeneration.

Application of eGFP to label human periodontal ligament stem cells in periodontal tissue engineering.

OBJECTIVES: To establish human periodontal ligament stem cells (hPDLSC) with high and stable expression of enhanced green fluorescent protein (eGFP) and to obtain an ideal vector expression system that suitable for gene therapy in periodontal tissue engineering. METHODS: hPDLSCs were transfected with eGFP for 48h via different MOI (25, 50, 100, 200 and 400) by lentiviral vector, the transfection efficiency was evaluated by fluorescent microscopy and flow cytometry, and transfected hPDLSCs proliferation was evaluated by MTT. Pluripotent, differentiation capacity and ALP expression status were determined further. Osteoblast-associated genes expressions for osteogenesis were evaluated by quantitative-PCR. In addition, rat molar periodontal fenestration defect model was used for evaluating periodontal tissue engineering. RESULTS: The transfection efficiency after 48h were 44.7%, 60.9%, 71.7%, 85.8%, and 86.9% respectively. There was no significant effect of transfection (at different MOI levels of 25, 50, 100, and 200) on the proliferation of hPDLSCs (designated as eGFP-hPDLSCs) compared with hPDLSCs (P>0.05). However, proliferation of eGFP hPDLSCs at MOI 400 became slower (P<0.05). Both eGFP hPDLSCs and hPDLSCs were able to differentiate into osteocytes and adipocytes under certain conditioned media. At 7 days, expression levels of COL-1, RUNX2 in hPDLSCS were higher than those in eGFP hPDLSCs (P<0.05); expression levels of ALP and OPN in eGFP hPDLSCs were similar to those in hPDLSCs (P>0.05). Newly regenerated bone formation was observed in the defect model used. CONCLUSIONS: Among the transfection conditions, 48h transfection at MOI 200 is optimal for labelling hPDLSCs with eGFP in a lentiviral vector. There is no change in capability of the eGFP hPDLSCs osteogenesis. The lentiviral vector with eGFP is an appropriate expression vector system and hPDLSCs are ideal seeding cells for gene therapy in periodontal tissue engineering.

Bone repair by periodontal ligament stem cellseeded nanohydroxyapatite-chitosan scaffold.

BACKGROUND: A nanohydroxyapatite-coated chitosan scaffold has been developed in recent years, but the effect of this composite scaffold on the viability and differentiation of periodontal ligament stem cells (PDLSCs) and bone repair is still unknown. This study explored the behavior of PDLSCs on a new nanohydroxyapatite-coated genipin-chitosan conjunction scaffold (HGCCS) in vitro as compared with an uncoated genipin-chitosan framework, and evaluated the effect of PDLSC-seeded HGCCS on bone repair in vivo. METHODS: Human PDLSCs were cultured and identified, seeded on a HGCCS and on a genipin-chitosan framework, and assessed by scanning electron microscopy, confocal laser scanning microscopy, MTT, alkaline phosphatase activity, and quantitative real-time polymerase chain reaction at different time intervals. Moreover, PDLSC-seeded scaffolds were used in a rat calvarial defect model, and new bone formation was assessed by hematoxylin and eosin staining at 12 weeks postoperatively. RESULTS: PDLSCs were clonogenic and positive for STRO-1. They had the capacity to undergo osteogenic and adipogenic differentiation in vitro. When seeded on HGCCS, PDLSCs exhibited significantly greater viability, alkaline phosphatase activity, and upregulated the bone-related markers, bone sialoprotein, osteopontin, and osteocalcin to a greater extent compared with PDLSCs seeded on the genipin-chitosan framework. The use of PDLSC-seeded HGCCS promoted calvarial bone repair. CONCLUSION: This study demonstrates the potential of HGCCS combined with PDLSCs as a promising tool for bone regeneration.

Application of induced pluripotent stem cells in generation of a tissue-engineered tooth-like structure.

Stem cells, such as adult stem cells or embryonic stem cells, are the most important seed cells employed in tooth tissue engineering. Even though dental-derived stem cells are a good source of seed cells for such procedures, they are not often used in clinical applications because of the limited supply. Induced pluripotent stem (iPS) cells, with their high proliferation and differentiation ability, are now considered a promising alternative. The objectives of this study were to assess the role of iPS cells in tooth tissue engineering. We used real-time polymerase chain reaction to confirm that mouse iPS (miPS) cells can be induced to express both odontogenic and osteogenic gene profiles. We then established a tooth germ model and transplanted the recombinant tooth germ into a mouse subrenal capsule for 4 weeks to reproduce early-tooth organogenesis. After 4 weeks, hematoxylin and eosin staining results showed newly formed bone-like and dental pulp-like areas. Further immunohistochemical staining confirmed that osteopontin was present in the apical part of the tooth-like structure. These results demonstrate that miPS cells have the potential to differentiate into odontogenic cells, confirming that they could be a new source of seed cells for use in tooth tissue engineering.

Gingiva-derived mesenchymal stem cell-mediated therapeutic approach for bone tissue regeneration.

Up to now, the gingiva-derived mesenchymal stem cells (GMSCs) as a new postnatal stem cells have been isolated and characterized with multipotential differentiation capabilities in vitro. However, the in vivo efficacy of utilizing the GMSCs in bone regeneration remains obscure. First of all, we identified canonical MSCs in human gingival tissue, which possessed homogenous immunophenotype (CD34(-)CD45(-)CD29(+)CD105(+)CD90(+) STRO-1(+)) and had tri-lineage differentiation potential (osteoblasts, adipocytes, and chondrocytes). Next, we examined the efficacy of utilizing these stem cells in bone tissue regeneration; the enhanced green fluorescent protein-labeled GMSCs seeded on type I collagen gel were implanted into the mandibular defects as well as the critical-sized calvarial defects in Sprague Dawley rats. We first demonstrated that GMSCs could repair the mandibular wounds and calvarial defects at 2 months in rats postsurgical reconstruction. Histomorphological analysis and image of fluorescence microscope certified that new bone in the defect areas was derived from the transplanted GMSCs. Immunohistochemical analysis of green fluorescent protein, human collagen I, and osteopontin further confirmed our conclusion. The above results implied that mesenchymal stem cells derived from gingival tissue could be a novel source for stem cell-based therapy in bone reconstruction in clinical applications.

[Biological effects of phenytoin on cultured human periodontal ligament fibroblasts in vitro].

OBJECTIVE: To study the biological effects of phenytoin (PHT) on cultured human periodontal ligament fibroblasts (hPDLF), and explore the possibility of its accelerating periodontal regeneration. METHODS: Increasing concentrations of PHT (1, 5, 20, 100, 500, 2 500 mg/L) were added into the medium of the fourth passage of cultured hPDLF, respectively. After co-incubated for 3 days, cell proliferation activity, the total amount of protein and alkaline phosphatase (ALP) activity were detected. Mineralized sodium and PHT (20, 100, 500 mg/L) were added into the medium of the fourth passage hPDLF. After co-incubated, the mineralized nodules formation were detected by Von Kossa staining. The third passage hPDLF were stimulated by PHT (20, 100 mg/L), bone morphogenetic protein-2 (BMP-2) concentration was analyzed by enzyme linked immunosorbent sandwich assay (ELISA). RESULTS: At the concentration of 20 or 100 mg/L, PHT significantly enhanced the proliferating activity and ALP activity of hPDLF (P<0.01). PHT at 100 mg/L could increase protein synthesis of hPDLF (P<0.05). The capability of mineralization and BMP-2 expression of hPDLF were increased significantly (P<0.01) in 100 mg/L group when compared with that in the control group. However, higher concentration (2 500 mg/L) not only changed cell morphology, but also significantly inhibited cell activity. CONCLUSION: The results suggested that proper doses of PHT could promote proliferation and biosynthesis and also enhance osteogenesis by increasing the differentiation, mineralization and BMP-2 expression of hPDLF while higher concentrations of PHT had cytotoxic effect.