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Interleukin-1β-induced autophagy-related gene 5 regulates proliferation of embryonic stem cell-derived odontoblastic cells. PLoS One 2015; 10:e0124542. [PMID: 25894570 PMCID: PMC4403923 DOI: 10.1371/journal.pone.0124542] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 03/15/2015] [Indexed: 01/05/2023] Open
Abstract
We previously established a method for the differentiation of induced pluripotent stem cells and embryonic stem cells into α2 integrin-positive odontoblast-like cells. We also reported that Wnt5 in response to interleukin (IL)-1β induces matrix metalloproteinase (MMP)-3-regulated cell proliferation in these cells. Our findings suggest that MMP-3 plays a potentially unique physiological role in the generation of odontoblast-like cells under an inflammatory state. Here, we examined whether up-regulation of autophagy-related gene (Atg) 5 by IL-1β was mediated by Wnt5 signaling, thus leading to increased proliferation of odontoblast-like cells. IL-1β increased the mRNA and protein levels of Atg5, microtubule-associated protein 1 light chain (LC3, a mammalian homolog of yeast Atg8) and Atg12. Treatment with siRNAs against Atg5, but not LC3 and Atg12, suppressed the IL-1β-induced increase in MMP-3 expression and cell proliferation. Our siRNA analyses combined with western blot analysis revealed a unique sequential cascade involving Atg5, Wnt5a and MMP-3, which resulted in the potent increase in odontoblastic cell proliferation. These results demonstrate the unique involvement of Atg5 in IL-1β-induced proliferation of embryonic stem cell-derived odontoblast-like cells.
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102
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Towards unraveling the human tooth transcriptome: the dentome. PLoS One 2015; 10:e0124801. [PMID: 25849153 PMCID: PMC4388651 DOI: 10.1371/journal.pone.0124801] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 03/18/2015] [Indexed: 01/03/2023] Open
Abstract
The goal of the study was to characterize the transcriptome profiles of human ameloblasts and odontoblasts, evaluate molecular pathways and advance our knowledge of the human "dentome". Laser capture microdissection was used to isolate odontoblasts and ameloblasts from human tooth buds (15-20week gestational age) from 4 fetuses. RNA was examined using Agilent 41k whole genome arrays at 2 different stages of enamel formation, presecretory and secretory. Probe detection was considered against the array negative control to control for background noise. Differential expression was examined using Significance Analysis of Microarrays (SAM) 4.0 between different cell types and developmental stages with a false discovery rate of 20%. Pathway analysis was conducted using Ingenuity Pathway Analysis software. We found that during primary tooth formation, odontoblasts expressed 14,802 genes, presecretory ameloblasts 15,179 genes and secretory ameloblasts 14,526 genes. Genes known to be active during tooth development for each cell type (eg COL1A1, AMELX) were shown to be expressed by our approach. Exploring further into the list of differentially expressed genes between the motile odontoblasts and non-motile presecretory ameloblasts we found several genes of interest that could be involved in cell movement (FN1, LUM, ASTN1). Furthermore, our analysis indicated that the Phospholipase C and ERK5 pathways, that are important for cell movement, were activated in the motile odontoblasts. In addition our pathway analysis identified WNT3A and TGFB1 as important upstream contributors. Recent studies implicate these genes in the development of Schimke immuno-osseous dysplasia. The utility of laser capture microdissection can be a valuable tool in the examination of specific tissues or cell populations present in human tooth buds. Advancing our knowledge of the human dentome and related molecular pathways provides new insights into the complex mechanisms regulating odontogenesis and biomineralization. This knowledge could prove useful in future studies of odontogenic related pathologies.
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103
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Soares DG, Marcomini N, Basso FG, Pansani TN, Hebling J, de Souza Costa CA. Indirect cytocompatibility of a low-concentration hydrogen peroxide bleaching gel to odontoblast-like cells. Int Endod J 2015; 49:26-36. [PMID: 25557717 DOI: 10.1111/iej.12426] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 12/23/2014] [Indexed: 12/27/2022]
Abstract
AIM To assess the initial cytotoxicity and the late phenotype marker expression of odontoblast-like cells (MDPC-23) subjected to less aggressive in-office bleaching therapies. METHODOLOGY A 17.5% hydrogen peroxide (H2O2) gel was applied for 45, 15 or 5 min to enamel/dentine discs adapted to trans-wells positioned over cultured MDPC-23 cells. No treatment was performed on the negative control. Immediately after bleaching, the cell viability, gene expression of inflammatory mediators and quantification of H2O2 diffusion were evaluated. The ALP activity, DSPP and DMP-1 gene expression and mineralized nodule deposition (MND) were assessed at 7, 14 or 21 days post-bleaching and analysed statistically with Mann-Whitney U-tests (α = 5%). RESULTS H2O2 diffusion, proportional to treatment time, was observed in all bleached groups. Reductions of approximately 31%, 21% and 13% in cell viability were observed for the 45-, 15- and 5-min groups, respectively. This reduction was significant (P < 0.05) for the 45- and 15-min groups, which also presented significant (P < 0.05) over-expression of inflammatory mediators. The 45-min group was associated with significant (P < 0.05) reductions in DMP-1/DSPP expression at all periods, relative to control. The ALP activity and MND were reduced only in initial periods. The 15-min group had less intense reduction of all markers, with no difference to control at 21 days. CONCLUSIONS The 17.5% H2O2 applied to tooth specimens for 5 min caused no alteration in the odontoblast-like cells. When this gel was applied for 45 or 15 min, a slight cytotoxicity, associated with alterations in phenotypic markers, was observed. However, cells were able to recover their functions up to 21 days post-bleaching.
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Affiliation(s)
- D G Soares
- Department of Physiology and Pathology, Araraquara School of Dentistry, University of Estadual Paulista (UNESP), Araraquara, Brazil
| | - N Marcomini
- Department of Physiology and Pathology, Araraquara School of Dentistry, University of Estadual Paulista (UNESP), Araraquara, Brazil
| | - F G Basso
- Department of Orthodontics and Pediatric Dentistry, Araraquara School of Dentistry, University of Estadual Paulista (UNESP), Araraquara, Brazil
| | - T N Pansani
- Department of Dental Materials and Prosthodontics, Araraquara School of Dentistry, University of Estadual Paulista (UNESP), Araraquara, Brazil
| | - J Hebling
- Department of Orthodontics and Pediatric Dentistry, Araraquara School of Dentistry, University of Estadual Paulista (UNESP), Araraquara, Brazil
| | - C A de Souza Costa
- Department of Physiology and Pathology, Araraquara School of Dentistry, University of Estadual Paulista (UNESP), Araraquara, Brazil
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104
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Nakagawa A, Okinaga T, Ariyoshi W, Morotomi T, Kitamura C, Nishihara T. Effects of Interferon-γ on odontoblastic differentiation and mineralization of odontoblast-like cells. Inflamm Regen 2015. [DOI: 10.2492/inflammregen.35.210] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Aika Nakagawa
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, Fukuoka, Japan
- Division of Pulp Biology, Operative Dentistry and Endodontology, Department of Cariology and Periodontology, Kyushu Dental University, Fukuoka, Japan
| | - Toshinori Okinaga
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, Fukuoka, Japan
| | - Wataru Ariyoshi
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, Fukuoka, Japan
| | - Takahiko Morotomi
- Division of Pulp Biology, Operative Dentistry and Endodontology, Department of Cariology and Periodontology, Kyushu Dental University, Fukuoka, Japan
| | - Chiaki Kitamura
- Division of Pulp Biology, Operative Dentistry and Endodontology, Department of Cariology and Periodontology, Kyushu Dental University, Fukuoka, Japan
| | - Tatsuji Nishihara
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, Fukuoka, Japan
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105
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Moncada G, Vildósola P, Fernández E, Estay J, de Oliveira Júnior OB, de Andrade MF, Martin J, Mjör IA, Gordan VV. Longitudinal Results of a 10-year Clinical Trial of Repair of Amalgam Restorations. Oper Dent 2015; 40:34-43. [DOI: 10.2341/14-045-c] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
SUMMARY
The aim of this prospective, blind, and randomized clinical trial was to assess the effectiveness of repair of localized clinical defects in amalgam restorations that were initially scheduled for replacement. A cohort of 20 patients with 40 (Class I and Class II) amalgam restorations that presented one or more clinical features that deviated from the ideal (Bravo or Charlie) according to US Public Health Service criteria, were randomly assigned to either the repair or the replacement group—A: repair, n = 19; and B: replacement, n = 21. Two examiners who had calibration expertise evaluated the restorations at baseline and 10 years after according to seven parameters: marginal occlusal adaptation, anatomic form, surface roughness, marginal staining, contact, secondary caries, and luster. After 10 years, 30 restorations (75%) were evaluated (Group A: n = 17; Group B: n = 13). Repaired and replaced amalgam restorations showed similar survival outcomes regarding marginal defects and secondary caries in patients with low and medium caries risk, and most of the restorations were considered clinically acceptable after 10 years. Repair treatment increased the potential for tooth longevity, using a minimally interventional procedure. All restorations trend to downgrade over time.
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Affiliation(s)
- G Moncada
- Gustavo Moncada, DDS, Dental School, Universidad Mayor, Santiago, Chile
| | - P Vildósola
- Patricio Vildósola, DDS, Dental School, University of Chile, Santiago, Chile
| | - E Fernández
- Eduardo Fernández, PhD, Restorative Dentistry, University of Chile, Santiago, Chile
| | - J Estay
- Juan Estay, DDS, Restorative Dentistry, University of Chile, Santiago, Chile
| | | | - MF de Andrade
- Marcelo Ferrarezi de Andrade, DDS, MSc, PhD, Department of Restorative Dentistry, Araraquara School of Dentistry, Universidade Estadual Paulista, Araraquara, Brazil
| | - J Martin
- Javier Martin, DDS, Restorative Dentistry, University of Chile, Santiago, Chile
| | | | - VV Gordan
- Valeria V Gordan, DDS, MS, MSCI, ad hoc reviewer, Department of Restorative Dental Sciences, University of Florida, Gainesville, FL, USA
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106
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Effect of hydrogen-peroxide-mediated oxidative stress on human dental pulp cells. J Dent 2014; 43:750-6. [PMID: 25527247 DOI: 10.1016/j.jdent.2014.12.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 12/02/2014] [Accepted: 12/05/2014] [Indexed: 01/01/2023] Open
Abstract
OBJECTIVES To evaluate the effect of the oxidative stress on human dental pulp cells (HDPCs) promoted by toxic concentrations of hydrogen peroxide (H2O2) on its odontoblastic differentiation capability through time. METHODS HDPCs were exposed to two different concentrations of H2O2 (0.1 and 0.3μg/ml) for 30min. Thereafter, cell viability (MTT assay) and oxidative stress generation (H2DCFDA fluorescence assay) were immediately evaluated. Data were compared with those for alkaline phosphatase (ALP) activity (thymolphthalein assay) and mineralized nodule deposition (alizarin red) by HDPCs cultured for 7 days in osteogenic medium. RESULTS A significant reduction in cell viability and oxidative stress generation occurred in the H2O2-treated cells when compared with negative controls (no treatment), in a concentration-dependent fashion. Seven days after H2O2 treatment, the cells showed significant reduction in ALP activity compared with negative control and no mineralized nodule deposition. CONCLUSION Both concentrations of H2O2 were toxic to the cells, causing intense cellular oxidative stress, which interfered with the odontogenic differentiation capability of the HDPCs. CLINICAL SIGNIFICANCE The intense oxidative stress on HDPCs mediated by H2O2 at toxic concentrations promotes intense reduction on odontoblastic differentiation capability in a 7-day evaluation period, which may alter the initial pulp healing capability in the in vivo situation.
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107
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Pei F, Lin H, Liu H, Li L, Zhang L, Chen Z. Dual role of autophagy in lipopolysaccharide-induced preodontoblastic cells. J Dent Res 2014; 94:175-82. [PMID: 25297117 DOI: 10.1177/0022034514553815] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Odontoblasts derive from neural crest-derived odontogenic mesenchymal cells, and they are an important barrier of defense for the host. Survival and immunity of odontoblasts play important roles in protecting the dentin-pulp structure. Autophagy can eliminate damaged organelles and recycle cellular components to facilitate cellular homeostasis. Autophagy can be activated with external stressors, such as starvation, hypoxia, and infection. In this study, the role of autophagy in inflamed odontoblasts was explored, and its possible mechanism was investigated. Cell viability was not affected by mild lipopolysaccharide (LPS) stimulation, and autophagy was activated during this process. Immunofluorescence of light chain 3 confirmed that autophagy was induced with LPS treatment. Early-stage autophagy inhibition resulted in down-regulated cell viability, contrary to the up-regulated cell viability at late-stage autophagy inhibition. Western blot suggested that p-Akt and survivin were not activated in the early stage, and they gradually increased and peaked in the late stage. Meanwhile, autophagy was down-regulated through the Akt/mTOR/survivin pathway in the late stage. Thus, autophagy has a dual role in inflamed odontoblasts, which indicates its importance in maintaining the microenvironment homeostasis of odontoblasts. Autophagy was induced as a survival mechanism in the early stage, and it decreased through the Akt/mTOR/survivin signaling pathway in the late stage.
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Affiliation(s)
- F Pei
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory for Oral Biomedicine of Ministry of Education (KLOBM), School and Hospital of Stomatology, Wuhan University, Wuhan, China
| | - H Lin
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory for Oral Biomedicine of Ministry of Education (KLOBM), School and Hospital of Stomatology, Wuhan University, Wuhan, China
| | - H Liu
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory for Oral Biomedicine of Ministry of Education (KLOBM), School and Hospital of Stomatology, Wuhan University, Wuhan, China
| | - L Li
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory for Oral Biomedicine of Ministry of Education (KLOBM), School and Hospital of Stomatology, Wuhan University, Wuhan, China
| | - L Zhang
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory for Oral Biomedicine of Ministry of Education (KLOBM), School and Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Z Chen
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory for Oral Biomedicine of Ministry of Education (KLOBM), School and Hospital of Stomatology, Wuhan University, Wuhan, China
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108
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Daud S, Nambiar P, Hossain MZ, Rahman MRA, Bakri MM. Changes in cell density and morphology of selected cells of the ageing human dental pulp. Gerodontology 2014; 33:315-21. [PMID: 25266855 DOI: 10.1111/ger.12154] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/15/2014] [Indexed: 11/27/2022]
Abstract
OBJECTIVES The aim of this study was to determine the changes in cell density and morphology of selected cells of the ageing human dental pulp. BACKGROUND Changes in cell density and morphology of dental pulp cells over time may affect their capability to respond to tooth injury. MATERIALS AND METHODS One hundred thirty-one extracted teeth were obtained from individuals between the ages of 6 and 80 years. The apical 1/3 of the root region was removed from all teeth prior to routine processing for producing histological slides. The histology slides were used to study the changes in cell density and morphology of selected pulp cells; odontoblasts, subodontoblasts and fibroblasts in the crown and root regions of the dental pulp. Student's t-test and one-way anova were used for statistical analyses. RESULTS In all age groups, the cell density for all types of cells was found to be higher in the crown than in the root (p < 0.05). In general, the pulp cell density was found to decrease with age in both the crown and root regions. However, it was noted that the reduction of coronal odontoblasts occurred later in life (40-49 years) when compared to that of subodontoblasts or fibroblasts (30-39 years). CONCLUSIONS The density of the coronal pulp cells reduces and these cells undergo morphological changes with ageing of individuals and this may affect the pulp's ability to resist tooth injury.
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Affiliation(s)
- Sulinda Daud
- Dental Faculty, Segi University College, Petaling Jaya, Malaysia
| | - Prabhakaran Nambiar
- Department of Diagnostic Dental Practice, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia
| | - M Zakir Hossain
- Department of Oral Biology and Biomedical Sciences, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia
| | - Mas Rizal Ab Rahman
- Department of Oral Biology and Biomedical Sciences, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia
| | - Marina M Bakri
- Department of Oral Biology and Biomedical Sciences, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia
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109
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Immediate and late analysis of dental pulp stem cells viability after indirect exposition to alternative in-office bleaching strategies. Clin Oral Investig 2014; 19:1013-20. [PMID: 25248948 DOI: 10.1007/s00784-014-1321-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 09/15/2014] [Indexed: 01/27/2023]
Abstract
OBJECTIVES To evaluate human dental pulp stem cell viability and capacity to recover from experimental dental bleaching techniques. MATERIAL AND METHODS Enamel/dentin disks adapted to trans-wells were positioned on previously cultivated dental pulp stem cells. Bleaching gels containing 35, 17.5, 10, and 8 % hydrogen peroxide (H2O2) were applied one or three times (each application lasting 15 min) on enamel. Cell viability (MTT assay) and morphology (SEM) were evaluated immediately (T1) or 72 h (T2) post-bleaching. RESULTS The 35 % H2O2 gel promoted intense reduction in viability (93-97 %) and morphological alterations of the cells at T1, irrespective of frequency of application, with absence or limited capacity for recovery being observed at T2. The other bleaching gels presented significant lower toxicity when compared with the 35 % H2O2 gel, in a time/concentration fashion. In T1, no significant difference was observed between the negative control (without bleaching) and the 8 and 10 % H2O2 gels applied on enamel for 15 min, in which the cells presented elevated viability and morphology similar to the negative control at T2. CONCLUSIONS Bleaching gels with 8 and 10 % H2O2 in their composition cause limited immediate toxic effect on pulp stem cells, which recover their viability 3 days after treatment. CLINICAL RELEVANCE This study presents proposals for in-office dental bleaching to be performed with limited aggressive effect on dental pulp stem cells. Therefore, we are able to offer interesting clinical alternatives for bleaching vital teeth, under professional supervision, maintaining the integrity and reparative capacity of pulp-dentin complex.
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110
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Ricucci D, Loghin S, Lin LM, Spångberg LSW, Tay FR. Is hard tissue formation in the dental pulp after the death of the primary odontoblasts a regenerative or a reparative process? J Dent 2014; 42:1156-70. [PMID: 25008021 DOI: 10.1016/j.jdent.2014.06.012] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 05/19/2014] [Accepted: 06/30/2014] [Indexed: 01/09/2023] Open
Abstract
OBJECTIVES Conceptually, two types of tertiary dentine may be produced in response to caries and environmental irritations: "reactionary dentine" that is secreted by existing primary odontoblasts and "reparative dentine", formed after the death of the odontoblasts by proliferation and differentiation of progenitor cells into odontoblast-like cells. Because histologic evidence for tubular dentine generated by newly differentiated odontoblast-like cells is lacking in human teeth, the present study examined pulpal cellular changes associated with caries/restorations, in the presence or absence of pulpal exposures. METHODS Ninety-six extracted human teeth were histologically processed and serial sectioned for light microscopy: 65 contained untreated enamel/dentine caries; 20 were heavily restored and 11 had carious exposures managed by direct pulp-capping. RESULTS Sparsely distributed, irregularly arranged dentinal tubules were identified from the tertiary dentine formed in teeth with unexposed medium/deep caries and in restored teeth; those tubules were continuous with the tubules of secondary dentine; in some cases, tubules were absent. The palisade odontoblast layer was reduced to a single layer of flattened cells. In direct pulp-capping of pulp exposures, the defects were repaired by the deposition of an amorphous dystrophic calcified tissue that resembled pulp stones more than dentine, sometimes entrapping pulpal remnants. This atubular hard tissue was lined by fibroblasts and collagen fibrils. CONCLUSIONS Histological evidence from the present study indicates that reparative dentinogenesis cannot be considered as a regenerative process since the so-formed hard tissue lacks tubular features characteristic of genuine dentine. Rather, this process represents a repair response that produces calcified scar tissues by pulpal fibroblasts. CLINICAL SIGNIFICANCE Formation of hard tissue in the dental pulp after the death of the primary odontoblasts has often been regarded by clinicians as regeneration of dentine. If the objective of the clinical procedures involved is to induce healing, reduce dentine hypersensitivity, or minimise future bacteria exposure, such procedures may be regarded as clinical success. However, current clinical treatment procedures are not adept at regenerating physiological dentne because the tissues formed in the dental pulp are more likely the result of repair responses via the formation of calcified scar tissues.
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Affiliation(s)
| | | | - Louis M Lin
- Department of Endodontics, New York University, New York, USA
| | - Larz S W Spångberg
- Division of Endodontology, University of Connecticut School of Dental Medicine, Farmington, CT, USA
| | - Franklin R Tay
- Department of Endodontics, College of Dental Medicine, Georgia Regents University, Augusta, GA, USA.
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111
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Houshmandi M, Ye P, Hunter N. Glial network responses to polymicrobial invasion of dentin. Caries Res 2014; 48:534-48. [PMID: 24993646 DOI: 10.1159/000360610] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 02/08/2014] [Indexed: 11/19/2022] Open
Abstract
This study investigated the distribution patterns of glial networks disclosed by reactivity for glial fibrillary acidic protein (GFAP) and S100B in healthy and carious human teeth. The objective was to determine the assembly and collapse of glial networks in response to encroaching infection. 15 healthy and 37 carious posterior teeth from adults were studied. Immediately after extraction, teeth were cleaned and vertically split and the half with pulp fixed and prepared for resin or frozen sections. Sections were stained with toluidine blue and for immunofluorescence, with observation by confocal laser microscopy and analysis by ImageJ software. Carious teeth were subdivided into three groups according to degree of carious involvement: microbial penetration through enamel (stage A), extension into dentin (stage B) and advanced penetration into dentin but without invasion of underlying pulp tissue (stage C). In stage A lesions there was marked increase in glial networks in dental pulp tissue that extended beyond the zone of microbial invasion. This response was maintained in stage B lesions. In advanced stage C lesions these networks were degraded in the zone of invasion in association with failure to contain infection. Cells expressing the glial markers GFAP and S100B showed a response to initial microbial invasion of dentin by increase in number and altered anatomical arrangement. The late stage of dentinal caries was marked by collapse of these networks in the region adjacent to advancing bacteria. This behaviour is important for understanding and explaining the defensive response of the neurosensory peripheral dental pulp apparatus to infection.
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Affiliation(s)
- Mojgan Houshmandi
- Institute of Dental Research, Westmead Millennium Institute and Westmead Centre for Oral Health, Westmead Hospital, Westmead, N.S.W., Australia
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112
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113
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Bleicher F. Odontoblast physiology. Exp Cell Res 2014; 325:65-71. [DOI: 10.1016/j.yexcr.2013.12.012] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 12/03/2013] [Accepted: 12/08/2013] [Indexed: 11/25/2022]
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114
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de Souza Costa CA, Hebling J, Scheffel DL, Soares DG, Basso FG, Ribeiro APD. Methods to evaluate and strategies to improve the biocompatibility of dental materials and operative techniques. Dent Mater 2014; 30:769-84. [DOI: 10.1016/j.dental.2014.04.010] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 02/05/2014] [Accepted: 04/25/2014] [Indexed: 01/09/2023]
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115
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Couve E, Osorio R, Schmachtenberg O. Reactionary Dentinogenesis and Neuroimmune Response in Dental Caries. J Dent Res 2014; 93:788-93. [PMID: 24928097 DOI: 10.1177/0022034514539507] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Accepted: 05/22/2014] [Indexed: 12/22/2022] Open
Abstract
Reactionary dentin formation is an adaptive secretory response mediated by odontoblasts to moderate dentin injury. The implications of this process for neuroimmune interactions operating to contain pathogens have not been fully appreciated. The purpose of the present study was to describe the relationship between reactionary dentinogenesis, the neurogenic changes of dental pulp innervation, and dendritic cell recruitment to caries progression, using a comparative immunohistochemical approach in human teeth from young adult individuals. Reactionary dentin formation during dentin caries progression is associated with changes in the integrity of junctional complexes within the odontoblast layer. Diminished coexpression of Cx43 and zonula occludens 1 implies a reduced level of intercellular connectivity between odontoblasts. Dentin caries also causes overexpression of growth-associated protein 43, a modulator of neural plasticity that promotes extensive sprouting of nerve endings into the reactionary dentin matrix. At the same time, an elevated number of HLA-DR-positive dendritic cells infiltrate the odontoblast layer and subsequently invade reactionary dentin formed underneath the early caries-affected regions. Simultaneous odontoblast layer remodeling, nerve fiber sprouting, and activation of dendritic cells during caries progression suggest a coordinated neuroimmune response to fight caries pathogen invasion and to promote dentin-pulp healing. We propose that reactionary dentin formation hinders pathogen invasion and supports defensive neuroimmune interactions against infection. The eventual understanding of this complex scenario may contribute to the development of novel approaches to dental caries treatment.
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Affiliation(s)
- E Couve
- Instituto de Biología, Laboratorio de Microscopía Electrónica Centro Interdisciplinario de Neurociencia de Valparaíso Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - R Osorio
- Instituto de Biología, Laboratorio de Microscopía Electrónica Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - O Schmachtenberg
- Centro Interdisciplinario de Neurociencia de Valparaíso Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
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116
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Frost LS, Mitchell CH, Boesze-Battaglia K. Autophagy in the eye: implications for ocular cell health. Exp Eye Res 2014; 124:56-66. [PMID: 24810222 DOI: 10.1016/j.exer.2014.04.010] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 04/10/2014] [Accepted: 04/12/2014] [Indexed: 12/21/2022]
Abstract
Autophagy, a catabolic process by which a cell "eats" itself, turning over its own cellular constituents, plays a key role in cellular homeostasis. In an effort to maintain normal cellular function, autophagy is often up-regulated in response to environmental stresses and excessive organelle damage to facilitate aggregated protein removal. In the eye, virtually all cell types from those comprising the cornea in the front of the eye to the retinal pigment epithelium (RPE) providing a protective barrier for the retina at the back of the eye, rely on one or more aspects of autophagy to maintain structure and/or normal physiological function. In the lens autophagy plays a critical role in lens fiber cell maturation and the formation of the organelle free zone. Numerous studies delineating the role of Atg5, Vsp34 as well as FYCO1 in maintenance of lens transparency are discussed. Corneal endothelial dystrophies are also characterized as having elevated levels of autophagic proteins. Therefore, novel modulators of autophagy such as lithium and melatonin are proposed as new therapeutic strategies for this group of dystrophies. In addition, we summarize how corneal Herpes Simplex Virus (HSV-1) infection subverts the cornea's response to infection by inhibiting the normal autophagic response. Using glaucoma models we analyze the relative contribution of autophagy to cell death and cell survival. The cytoprotective role of autophagy is further discussed in an analysis of photoreceptor cell heath and function. We focus our analysis on the current understanding of autophagy in photoreceptor and RPE health, specifically on the diverse role of autophagy in rods and cones as well as its protective role in light induced degeneration. Lastly, in the RPE we highlight hybrid phagocytosis-autophagy pathways. This comprehensive review allows us to speculate on how alterations in various stages of autophagy contribute to glaucoma and retinal degenerations.
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Affiliation(s)
- Laura S Frost
- Department of Biochemistry, University of Pennsylvania, SDM, Philadelphia, PA 19104, USA
| | - Claire H Mitchell
- Department of Anatomy and Cell Biology, University of Pennsylvania, SDM, Philadelphia, PA 19104, USA
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117
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Bjørndal L, Demant S, Dabelsteen S. Depth and Activity of Carious Lesions as Indicators for the Regenerative Potential of Dental Pulp after Intervention. J Endod 2014; 40:S76-81. [DOI: 10.1016/j.joen.2014.01.016] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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118
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JÁGR M, ECKHARDT A, PATARIDIS S, BROUKAL Z, DUŠKOVÁ J, MIKŠÍK I. Proteomics of Human Teeth and Saliva. Physiol Res 2014; 63:S141-54. [DOI: 10.33549/physiolres.932702] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Teeth have been a focus of interest for many centuries – due to medical problems with them. They are the hardest part of the human body and are composed of three mineralized parts – enamel, dentin and cementum, together with the soft pulp. However, saliva also has a significant impact on tooth quality. Proteomic research of human teeth is now accelerating, and it includes all parts of the tooth. Some methodological problems still need to be overcome in this research field – mainly connected with calcified tissues. This review will provide an overview of the current state of research with focus on the individual parts of the tooth and pellicle layer as well as saliva. These proteomic results can help not only stomatology in terms of early diagnosis, identifying risk factors, and systematic control.
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Affiliation(s)
| | | | | | | | | | - I. MIKŠÍK
- Department of Analysis of Biologically Important Compounds, Institute of Physiology Academy of Sciences of the Czech Republic, Prague, Czech Republic
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119
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Lim WH, Liu B, Cheng D, Williams BO, Mah SJ, Helms JA. Wnt signaling regulates homeostasis of the periodontal ligament. J Periodontal Res 2014; 49:751-9. [PMID: 24410666 DOI: 10.1111/jre.12158] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/23/2013] [Indexed: 01/09/2023]
Abstract
BACKGROUND AND OBJECTIVE In health, the periodontal ligament maintains a constant width throughout an organism's lifetime. The molecular signals responsible for maintaining homeostatic control over the periodontal ligament are unknown. The purpose of this study was to investigate the role of Wnt signaling in this process by removing an essential chaperone protein, Wntless (Wls), from odontoblasts and cementoblasts, and observing the effects of Wnt depletion on cells of the periodontal complex. MATERIAL AND METHODS The Wnt responsive status of the periodontal complex was assessed using two strains of Wnt reporter mice: Axin2(LacZ/+) and Lgr5(LacZ/+) . The function of this endogenous Wnt signal was evaluated by conditionally eliminating the Wntless (Wls) gene using an osteocalcin Cre driver. The resulting OCN-Cre;Wls (fl/fl) mice were examined using micro-computed tomography and histology, immunohistochemical analyses for osteopontin, Runx2 and fibromodulin, in-situ hybridization for osterix and alkaline phosphatase activity. RESULTS The adult periodontal ligament is Wnt responsive. Elimination of Wnt signaling in the periodontal complex of OCN-Cre;Wls(fl/fl) mice resulted in a wider periodontal ligament space. This pathologically increased periodontal width is caused by a reduction in the expression of osteogenic genes and proteins, which results in thinner alveolar bone. A concomitant increase in fibrous tissue occupying the periodontal space was observed, along with a disruption in the orientation of the periodontal ligament. CONCLUSION The periodontal ligament is a Wnt-dependent tissue. Cells in the periodontal complex are Wnt responsive, and eliminating an essential component of the Wnt signaling network leads to a pathological widening of the periodontal ligament space. Osteogenic stimuli are reduced, and a disorganized fibrillary matrix results from the depletion of Wnt signaling. Collectively, these data underscore the importance of Wnt signaling in homeostasis of the periodontal ligament.
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Affiliation(s)
- W H Lim
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA; Department of Orthodontics, School of Dentistry & Dental Research Institute, Seoul National University, Seoul, Korea
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120
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Couve E, Schmachtenberg O. Response to letter to the editor, "the amazing odontoblast: activity, autophagy, and aging": why rename the amazing odontoblast? J Dent Res 2013; 92:1143. [PMID: 24127419 DOI: 10.1177/0022034513509380] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- E Couve
- Facultad de Ciencias, Universidad de Valparaíso, Avda. Gran Bretaña 1111, Playa Ancha, Valparaíso, Chile
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121
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Larmas M, Sándor GK. Letter to the editor, "the amazing odontoblast: activity, autophagy, and aging". J Dent Res 2013; 92:1142. [PMID: 24127418 DOI: 10.1177/0022034513507955] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- M Larmas
- Institute of Dentistry, University of Oulu, PO Box 5281, Oulu, Fin-90014, Finland
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