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Relationships of Stresses on Alveolar Bone and Abutment of Dental Implant from Various Bite Forces by Three-Dimensional Finite Element Analysis. BIOMED RESEARCH INTERNATIONAL 2020; 2020:7539628. [PMID: 32149132 PMCID: PMC7049827 DOI: 10.1155/2020/7539628] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Revised: 12/02/2019] [Accepted: 01/23/2020] [Indexed: 11/24/2022]
Abstract
Occlusal trauma caused by improper bite forces owing to the lack of periodontal membrane may lead to bone resorption, which is still a problem for the success of dental implant. In our study, to avoid occlusal trauma, we put forward a hypothesis that a microelectromechanical system (MEMS) pressure sensor is settled on an implant abutment to track stress on the abutment and predict the stress on alveolar bone for controlling bite forces in real time. Loading forces of different magnitudes (0 N–100 N) and angles (0–90°) were applied to the crown of the dental implant of the left central incisor in a maxillary model. The stress distribution on the abutment and alveolar bone were analyzed using a three-dimensional finite element analysis (3D FEA). Then, the quantitative relation between them was derived using Origin 2017 software. The results show that the relation between the loading forces and the stresses on the alveolar bone and abutment could be described as 3D surface equations associated with the sine function. The appropriate range of stress on the implant abutment is 1.5 MPa–8.66 MPa, and the acceptable loading force range on the dental implant of the left maxillary central incisor is approximately 6 N–86 N. These results could be used as a reference for the layout of MEMS pressure sensors to maintain alveolar bone dynamic remodeling balance.
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Lee DJ, Lee JM, Kim EJ, Takata T, Abiko Y, Okano T, Green DW, Shimono M, Jung HS. Bio-implant as a novel restoration for tooth loss. Sci Rep 2017; 7:7414. [PMID: 28784994 PMCID: PMC5547161 DOI: 10.1038/s41598-017-07819-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 07/03/2017] [Indexed: 12/26/2022] Open
Abstract
A dental implant is used to replace a missing tooth. Fixing the implant in its natural position requires the engineering of a substantial amount of conformal bone growth inside the implant socket, osseointegration. However, this conventional implant attachment does not include the periodontal ligament (PDL), which has a fundamental role in cushioning high mechanical loads. As a result, tooth implants have a shorter lifetime than the natural tooth and have a high chance of infections. We have engineered a "bio-implant" that provides a living PDL connection for titanium implants. The bio-implant consists of a hydroxyapatite coated titanium screw, ensheathed in cell sheets made from immortalized human periodontal cells. Bio-implants were transplanted into the upper first molar region of a tooth-extraction mouse model. Within 8 weeks the bio-implant generated fibrous connective tissue, a localised blood vessel network and new bone growth fused into the alveolar bone socket. The study presents a bio-implant engineered with human cells, specialised for the root connection, and resulted in the partial reconstruction of a naturalised tooth attachment complex (periodontium), consisting of all the principal tissue types, cementum, PDL and alveolar bone.
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Affiliation(s)
- Dong-Joon Lee
- Division in Anatomy and Developmental Biology, Department of Oral Biology, Oral Science Research Center, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, Korea
| | - Jong-Min Lee
- Division in Anatomy and Developmental Biology, Department of Oral Biology, Oral Science Research Center, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, Korea
| | - Eun-Jung Kim
- Division in Anatomy and Developmental Biology, Department of Oral Biology, Oral Science Research Center, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, Korea
| | - Takashi Takata
- Department of Oral Pathology, Faculty of Dentistry, Hiroshima University, Hiroshima, Japan
| | - Yoshihiro Abiko
- Division of Oral Medicine and Pathology, Department of Human Biology and Pathophysiology, School of Dentistry, Health Sciences University of Hokkaido, Hokkaido, Japan
| | - Teruo Okano
- Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, Tokyo, Japan
| | - David W Green
- Division in Anatomy and Developmental Biology, Department of Oral Biology, Oral Science Research Center, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, Korea
| | - Masaki Shimono
- Department of Pathology, Tokyo Dental College, Chiba, Japan
| | - Han-Sung Jung
- Division in Anatomy and Developmental Biology, Department of Oral Biology, Oral Science Research Center, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, Korea. .,Applied Oral Science, Faculty of Dentistry, The University of Hong Kong, Hong Kong, SAR, China.
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3
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Tsuruga E, Irie K, Sakakura Y, Yajima T. Tropoelastin Expression by Periodontal Fibroblasts. J Dent Res 2017. [DOI: 10.1177/0810198] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Elastic system fibers are load-bearing proteins found in periodontal tissue. There are three types—oxytalan, elaunin, and elastic fibers—which differ in their relative microfibril and elastin contents. Oxytalan fibers are known to be distributed in the periodontal ligaments and gingiva, whereas elaunin and elastic fibers are present only in the gingiva. We examined gene expression and accumulation of tropoelastin in the cell-matrix layers of human gingival fibroblasts (HGF) and periodontal ligament fibroblasts (HPLF) in vitro. HGF and HPLF were cultured in MEM containing 10% newborn calf serum for 8 wks. Northern blotting and RT-PCR analyses showed that only HGF expressed mRNA encoding tropoelastin. Western blotting analysis demonstrated 77-kDa protropoelastin and 68-kDa tropoelastin only in the cell-matrix layer of HGF cultured for 8 wks. These results suggest that the different tropoelastin expression patterns reflect the difference between HGF and HPLF phenotypes.
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Affiliation(s)
- E. Tsuruga
- Department of Oral Anatomy, School of Dentistry, Health Sciences
University of Hokkaido, 1757 Kanazawa, Ishikari-Tobetsu, Hokkaido 061-0293,
Japan
| | - K. Irie
- Department of Oral Anatomy, School of Dentistry, Health Sciences
University of Hokkaido, 1757 Kanazawa, Ishikari-Tobetsu, Hokkaido 061-0293,
Japan
| | - Y. Sakakura
- Department of Oral Anatomy, School of Dentistry, Health Sciences
University of Hokkaido, 1757 Kanazawa, Ishikari-Tobetsu, Hokkaido 061-0293,
Japan
| | - T. Yajima
- Department of Oral Anatomy, School of Dentistry, Health Sciences
University of Hokkaido, 1757 Kanazawa, Ishikari-Tobetsu, Hokkaido 061-0293,
Japan
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Pêgo SPB, de Faria PR, Santos LAN, Coletta RD, de Aquino SN, Martelli-Júnior H. Ultrastructural evaluation of gingival connective tissue in hereditary gingival fibromatosis. Oral Surg Oral Med Oral Pathol Oral Radiol 2016; 122:81-88.e2. [PMID: 27260277 DOI: 10.1016/j.oooo.2016.04.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 04/02/2016] [Accepted: 04/05/2016] [Indexed: 01/07/2023]
Abstract
OBJECTIVE To describe the ultrastructural features of hereditary gingival fibromatosis (HGF) in affected family members and compare microscopic findings with normal gingival (NG) tissue. STUDY DESIGN Gingival tissue samples from nine patients with HGF from five unrelated families were evaluated by transmission electron microscopy. Nine NG tissue samples were used for comparison. RESULTS Areas containing collagen fibrils forming loops and folds were observed in both groups, whereas oxytalan fibers were frequently identified in the HGF group. The diameter of collagen fibrils and the interfibrillar space among them were more uniform in the NG group than in the HGF group. Fibroblasts were the most common cells found in both the HGF and NG groups and exhibited enlarged, rough endoplasmic reticulum, mitochondria with well-preserved crests, conspicuous nucleoli, and euchromatic chromatin. Other cells, such as mast cells, plasma cells, and macrophages, were also observed. CONCLUSIONS HGF tissues had ultrastructural characteristics that were very similar to those of NG tissues. Oxytalan fibers were observed more frequently in the HGF samples than in the NG samples. Other studies of HGF in patients from different families should be performed to better understand the pathogenesis of this hereditary condition.
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Affiliation(s)
- Sabina Pena B Pêgo
- Full Professor, Dental School, State University of Montes Claros, Av Rui Braga - Vila Mauriceia - Campus Darcy Ribeiro - CEP 39401-089, Montes Claros, Minas Gerais, Brazil.
| | - Paulo Rogério de Faria
- Adjunct Professor, Institute of Biomedical Science, Department of Morphology, Federal University of Uberlandia, Uberlandia, Minas Gerais, Brazil
| | - Luis Antônio N Santos
- Full Professor, Dental School, State University of Montes Claros, Av Rui Braga - Vila Mauriceia - Campus Darcy Ribeiro - CEP 39401-089, Montes Claros, Minas Gerais, Brazil
| | - Ricardo D Coletta
- Associate Professor, Department of Oral Diagnosis, School of Dentistry, State University of Campinas, São Paulo, Brazil
| | - Sibele Nascimento de Aquino
- Professor, Department of Oral Dentistry, Federal University of Juiz de Fora, Governador Valadares, Minas Gerais, Brazil
| | - Hercílio Martelli-Júnior
- Full Professor, Dental School, State University of Montes Claros, Av Rui Braga - Vila Mauriceia - Campus Darcy Ribeiro - CEP 39401-089, Montes Claros, Minas Gerais, Brazil
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Inoue K, Hara Y, Kuroda N, Sato T. Development of the oxytalan fiber system in the periodontal space of rat incisors. Ann Anat 2013; 195:475-83. [DOI: 10.1016/j.aanat.2013.03.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 03/29/2013] [Accepted: 03/30/2013] [Indexed: 10/26/2022]
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Tsuruga E, Oka K, Hatakeyama Y, Isokawa K, Sawa Y. Latent transforming growth factor-β binding protein 2 negatively regulates coalescence of oxytalan fibers induced by stretching stress. Connect Tissue Res 2012; 53:521-7. [PMID: 22827404 DOI: 10.3109/03008207.2012.702816] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Oxytalan fibers are extracellular matrix components consisting of pure microfibrils. However, the mechanism whereby oxytalan fibers develop is not fully understood. We have previously reported that in human periodontal ligament (PDL) fibroblasts subjected to stretching stress, bundles of oxytalan fibers coalesce under the control of fibulin-5. Latent transforming growth factor-β binding protein 2 (LTBP-2) is known to bind to fibulin-5. The purpose of this study was to clarify the role of LTBP-2 in the coalescence of oxytalan fibers. We subjected PDL fibroblasts to stretching in order to examine the effects of LTBP-2 on the coalescence of oxytalan fibers in cell/matrix layers. Interaction of LTBP-2 with fibulin-5 was examined by immunoprecipitation assay, and changes in LTBP-2 deposition upon stretching were investigated by Western blotting and immunofluorescence assays. We used small interfering RNA against LTBP-2 in PDL cell culture and examined the appearance of oxytalan fibers on the basis of immunofluorescence. Stretching induced coalescence of oxytalan fibers, but did not affect LTBP-2 expression. The amount of extracellularly deposited LTBP-2 was decreased by about 70% as a result of stretching, compared with the control. LTBP-2 interacted with fibulin-5 on the fibers, and stretching decreased the amount of the LTBP-2 interacted with fibulin-5 by about 60%. Oxytalan fiber coalescence did not occur when LTBP-2 was suppressed by about 95%, whereas it occurred when LTBP-2 was suppressed by about 40%, fibulin-5 being colocalized with oxytalan fibers. These results suggest that LTBP-2, in response to tension stress, may negatively control the function of fibulin-5, thereby modulating the mechanism of oxytalan fiber coalescence.
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Affiliation(s)
- Eichi Tsuruga
- Section of Functional Structure, Division of Biomedical Sciences, Department of Morphological Biology, Fukuoka Dental College, Sawara-ku, Fukuoka, Japan.
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Strydom H, Maltha JC, Kuijpers-Jagtman AM, Von den Hoff JW. The oxytalan fibre network in the periodontium and its possible mechanical function. Arch Oral Biol 2012; 57:1003-11. [PMID: 22784380 DOI: 10.1016/j.archoralbio.2012.06.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Revised: 05/29/2012] [Accepted: 06/13/2012] [Indexed: 01/20/2023]
Abstract
The biomechanical character of the periodontal ligament (PDL) is crucial in its response to functional and orthodontic forces. Collagen has been the primary subject of investigations in this field. Several studies, however, indicate that oxytalan fibres, which belong to the elastic fibre family, also contribute to the biomechanical character and behaviour of the PDL. In order to elucidate this, we have evaluated the available literature on the oxytalan fibre network within the PDL and supra-alveolar tissues with respect to development, morphology and distribution, and response to mechanical stimulation. To this end, we have combined the classical histological studies with more recent in vitro studies. Oxytalan fibres develop simultaneously with the root and the vascular system within the PDL. A close association between oxytalan fibres and the vascular system also remains later in life, suggesting a role in vascular support. Mechanical loading of the PDL, through orthodontic force application, appears to induce an increase in the number, size, and length of oxytalan fibres. In line with this, in vitro stretching of PDL fibroblasts (PDLFs) results in an increased production of fibrillin, a major structural component of the microfibrils that make up oxytalan fibres. The available data suggest a mechanical function for oxytalan, but to date experimental data are limited. Further research is required to clarify their exact mechanical function and possible role in orthodontic tooth movement.
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Affiliation(s)
- Hardus Strydom
- Department of Orthodontics and Craniofacial Biology, Radboud University Nijmegen Medical Centre, The Netherlands
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8
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Inoue K, Hara Y, Sato T. Development of the oxytalan fiber system in the rat molar periodontal ligament evaluated by light- and electron-microscopic analyses. Ann Anat 2012; 194:482-8. [PMID: 22727934 DOI: 10.1016/j.aanat.2012.03.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Revised: 03/23/2012] [Accepted: 03/30/2012] [Indexed: 11/27/2022]
Abstract
In the elastic fiber system of the periodontal ligaments only oxytalan fibers can be identified, whereas all three types of fibers, oxytalan, elaunin and elastic fibers, are present in the gingiva. However, little information is available concerning their organization in the developing periodontal ligament. In the present study, growth and distribution of the oxytalan fiber system were examined in the developing periodontal ligament of rat molars using the specific staining for oxytalan, elastic and collagen fibers, and electron-microscopic analyses. Oxytalan staining clearly confirmed the earliest oxytalan fibers in a bell-staged tooth germ at embryonic day 18, which were tiny violet-colored fibers in the dental follicle. Their cross images were made up of dot-like microfibrils of 10-15nm in diameter close to fibroblasts in the dental follicle of the rat molars aged 1 day. These microfibrils appeared to be linked to one another through delicate filaments in 3-nm-diameter. At the beginning of root formation, the cross figures of oxytalan fibers were found as dot-like structures around the root sheath as well as in areas very close to blood vessels. As development proceeded, longer oxytalan fibers were produced in the apico-occlusal direction along with blood vessels. In addition, the immunoreactive products to anti-amyloid β protein on the surface of blood vessels suggest that this molecule might be involved in the adhesion of oxytalan fibers to vascular basement membranes. Thus, the oxytalan fiber system might regulate periodontal ligament function through tensional variations registered on the walls of the vascular structures.
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Affiliation(s)
- Kouji Inoue
- Research Center of Electron Microscopy, School of Dental Medicine, Tsurumi University, Yokohama, Japan.
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Hisanaga Y, Nakashima K, Tsuruga E, Nakatomi Y, Hatakeyama Y, Ishikawa H, Sawa Y. Fibulin-5 contributes to microfibril assembly in human periodontal ligament cells. Acta Histochem Cytochem 2009; 42:151-7. [PMID: 19918324 PMCID: PMC2775106 DOI: 10.1267/ahc.09021] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Accepted: 08/18/2009] [Indexed: 11/22/2022] Open
Abstract
The elastic system fibers comprise oxytalan, elaunin and elastic fibers, which differ in their relative microfibril and elastin content. Human periodontal ligaments (PDL) contain only oxytalan fibers (pure microfibrils) among them. Since fibulin-5 regulates the organization of elastic fibers to link the fibers to cells, we hypothesized that fibulin-5 may contribute to the formation of oxytalan fibers. We used siRNA for fibulin-5 in PDL cell culture to examine the extracellular deposition of fibrillin-1 and -2, which are the major components of microfibrils. Fibulin-5 was labeled on microfibrils positive for fibrillin-1 and -2. Fibulin-5 suppression reduced the level of fibrillin-1 and -2 deposition to 60% of the control level. These results suggest that fibulin-5 may control the formation of oxytalan fibers, and play a role in the homeostasis of oxytalan fibers.
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Affiliation(s)
- Yutaka Hisanaga
- Section of Orthodontics, Department of Oral Growth & Development, Division of Clinical Dentistry, Fukuoka Dental College
| | - Kazuki Nakashima
- Section of Orthodontics, Department of Oral Growth & Development, Division of Clinical Dentistry, Fukuoka Dental College
| | - Eichi Tsuruga
- Section of Functional Structure, Department of Morphological Biology, Division of Biomedical Sciences, Fukuoka Dental College
| | - Yuka Nakatomi
- Section of Orthodontics, Department of Oral Growth & Development, Division of Clinical Dentistry, Fukuoka Dental College
| | - Yuji Hatakeyama
- Section of Functional Structure, Department of Morphological Biology, Division of Biomedical Sciences, Fukuoka Dental College
| | - Hiroyuki Ishikawa
- Section of Orthodontics, Department of Oral Growth & Development, Division of Clinical Dentistry, Fukuoka Dental College
| | - Yoshihiko Sawa
- Section of Functional Structure, Department of Morphological Biology, Division of Biomedical Sciences, Fukuoka Dental College
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10
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Nakashima K, Tsuruga E, Hisanaga Y, Ishikawa H, Sawa Y. Stretching stimulates fibulin-5 expression and controls microfibril bundles in human periodontal ligament cells. J Periodontal Res 2009; 44:622-7. [DOI: 10.1111/j.1600-0765.2008.01170.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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11
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Tsuruga E, Sato A, Ueki T, Nakashima K, Nakatomi Y, Ishikawa H, Yajima T, Sawa Y. Integrin alphavbeta3 regulates microfibril assembly in human periodontal ligament cells. Tissue Cell 2008; 41:85-9. [PMID: 18789468 DOI: 10.1016/j.tice.2008.07.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Revised: 07/18/2008] [Accepted: 07/25/2008] [Indexed: 10/21/2022]
Abstract
Fibrillin-1 is the major structural component of extracellular microfibrils. However, the mechanism by which extracellular fibrillin-1 assembles into microfibrils is not fully understood. Fibrillin-1 contains the Arg-Gly-Asp (RGD) motif, which may allow binding to RGD-recognizing integrins. We hypothesized that integrin alphavbeta3 on the cell surface of human periodontal ligament (PDL) fibroblasts may influence fibrillin-1 assembly into cell/matrix layers. We treated PDL fibroblasts with an integrin alphavbeta3-specific antagonist to examine fibrillin-1 assembly. Western blotting and immunofluorescence analysis showed that treatment with the integrin alphavbeta3 antagonist at 5 muM clearly abolished fibrillin-1 deposition. These results provide for the first time evidence that integrin alphavbeta3 regulates extracellular assembly of fibrillin-1, thereby modulating cell-mediated homeostasis of microfibrils.
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Affiliation(s)
- E Tsuruga
- Section of Functional Structure, Department of Morphological Biology, Division of Biomedical Sciences, Fukuoka Dental College, 2-15-1 Tamura, Sawara-ku, Fukuoka 814-0193, Japan.
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12
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Inoue M, Nagatsuka H, Tamamura R, Chong HS, Tsujigiwa H, Borkosky S, Fujii M, Nagai N, Setsu K. Localization of Oxytalan Fiber, type III Collagen and BMP Family in Conventional and Desmoplastic Ameloblastoma. J HARD TISSUE BIOL 2008. [DOI: 10.2485/jhtb.17.23] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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13
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Han X, Amar S. Secreted Frizzled-related Protein 1 (SFRP1) Protects Fibroblasts from Ceramide-induced Apoptosis. J Biol Chem 2004; 279:2832-40. [PMID: 14581477 DOI: 10.1074/jbc.m308102200] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Secreted frizzled-related proteins (SFRPs) are soluble proteins that have highly restricted tissue distribution. Although not fully understood, a role of SFRP1 in the regulation of apoptosis has been suggested. Our previous study disclosed a much greater level of SFRP1 expression in periodontal ligament fibroblasts (PDLFs), which have been suggested to maintain a reduced level of apoptosis compared with gingival fibroblasts. We have tested the role of SFRP1 in the regulation of fibroblast apoptosis both in vitro and in vivo. Our data showed that SFRP1 was significantly up-regulated in cultured human PDLFs during ceramide-induced apoptosis. In vivo study demonstrated an increased SFRP1 expression in mice periodontal ligament during force-induced apoptosis. While inhibition of endogenous SFRP1 increased the percentage of cell death in cultured human PDLFs, exogenous SFRP1 substantially reduced apoptosis in cultured human gingival fibroblasts, which do not maintain a high level of endogenous SFRP1 expression. The effect of SFRP1 on apoptosis was linked to the regulation of several apoptosis-related genes, including p53, caspase-3, caspase-9, and BCL-2-interacting killer (BIK). Furthermore our results indicated that the addition of exogenous SFRP1 could reduce the level of apoptosis in dermal fibroblasts in vivo, and this effect was also linked to the regulation of similar apoptosis-related genes as observed in in vitro studies. Collectively our results suggest that the constitutive up-regulation of SFRP1 could be an adaptive cell survival mechanism inherent to functionally specialized fibroblasts, and the addition of SFRP1 may contribute to the inhibition of apoptosis in fibroblast-related cells.
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Affiliation(s)
- Xiaozhe Han
- Department of Periodontology and Oral Biology, Goldman School of Dental Medicine, Boston University, Boston, Massachusetts 02118, USA
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14
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Abstract
BACKGROUND Studies have shown that periodontal ligament fibroblasts (PDLF) and gingival fibroblasts (GF) respond differently to growth factors in the repair and regeneration of periodontal tissues. The goal of this study was to determine the effects of insulin-like growth factor-1 (IGF-1) signaling on cell apoptosis in PDLF compared to GF. METHODS The levels of apoptosis were compared between cultured PDLF and GF by DNA fragmentation assay and trypan blue exclusion assay, either in the presence or absence of IGF-1. The transcript level of upstream signaling molecules, such as IGF binding protein-5 (IGFBP-5), IGF-1 receptor (IGF-1R), and phosphoinositide 3-kinase (PI3K), was studied using reverse transcription-polymerase chain reaction (RT-PCR). Furthermore, the role of IGFBP-5 in IGF-1 signaling was verified by annexin-V staining using flow cytometric analysis. RESULTS IGF-1 significantly inhibited the level of DNA fragmentation and decreased trypan blue-positive cells in PDLF compared to GF during serum deprivation. The mRNA expression of IGFBP-5, IGF-1R, and PI3K was constitutively upregulated in PDLF compared to GF. In the presence of exogenous IGFBP-5, the annexin-V-positive cells were significantly decreased in GF after IGF-1 stimulation. CONCLUSIONS The present study provides evidence that IGF-1 reduces apoptosis in cultured PDLF compared to GF. Upregulation of IGF-1R and PI3K in PDLF further suggests the activation of IGF signaling in PDLF. In addition, the anti-apoptotic effect of IGF-1 may be facilitated by the upregulation of IGFBP-5 in PDLF.
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Affiliation(s)
- Xiaozhe Han
- Department of Periodontology & Oral Biology, Goldman School of Dental Medicine, Boston University, Boston, MA, USA
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15
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Tsuruga E, Irie K, Yajima T. Gene expression and accumulation of fibrillin-1, fibrillin-2, and tropoelastin in cultured periodontal fibroblasts. J Dent Res 2002; 81:771-5. [PMID: 12407093 DOI: 10.1177/0810771] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The elastic system fibers consist of three types--oxytalan, elaunin, and elastic fibers--differing in their relative microfibril and elastin contents. All three types are found in human gingiva, but human periodontal ligaments contain only elastin-free fibers. We examined cultured human gingival fibroblasts (HGF) and cultured human periodontal ligament fibroblasts (HPLF) to determine the gene expression of fibrillin-1 and fibrillin-2 (the major components of microfibrils) and of tropoelastin. In addition, we assessed the degree of accumulation of these proteins in the extracellular matrix. Northern blot analysis revealed that the level of expression of fibrillin-1 and fibrillin-2 was higher in HGF than in HPLF. However, examination of matrix samples from HGF and HPLF cell layers showed that there was no difference in fibrillin-1 accumulation, although fibrillin-2 accumulated to a much greater extent in the HGF-derived matrix. Tropoelastin was expressed only in and around HGF. These results show a correlation between gene expression and the accumulation of tropoelastin and fibrillin-2 in HGF.
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Affiliation(s)
- E Tsuruga
- Department of Oral Anatomy, School of Dentistry, Health Sciences University of Hokkaido, 1757 Kanazawa, Ishikari-Tobetsu, Hokkaido 061-0293, Japan.
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16
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Barros SP, Merzel J, de Araújo VC, de Almeida OP, Bozzo L. Ultrastructural aspects of connective tissue in hereditary gingival fibromatosis. ORAL SURGERY, ORAL MEDICINE, ORAL PATHOLOGY, ORAL RADIOLOGY, AND ENDODONTICS 2001; 92:78-82. [PMID: 11458249 DOI: 10.1067/moe.2001.115026] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE The purpose of this study was to analyze the ultrastructure of gingival connective tissue from patients in one family affected by hereditary gingival fibromatosis (HGF). STUDY DESIGN Electron microscopic examination was performed with gingival tissue from 10 patients from a Brazilian family with 132 members. Fifty of 96 persons at risk for this disorder were affected, which is consistent with an autosomal dominant pattern of inheritance. RESULTS The extracellular matrix showed flocculent material and collagen fibrils with structural abnormalities and variation in diameter. Increased numbers of oxytalan fibers were identified; however, elastic fibers were rare in the analyzed areas. CONCLUSIONS The structural alterations found in HGF appear similar to those described in certain other heritable collagen disorders, suggesting that HGF should be included in the group of hereditary diseases in which connective tissue alterations have a distinct pattern, in contrast to reactive fibrotic gingival enlargements with no genetic component.
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Affiliation(s)
- S P Barros
- Department of Morphology, Faculty of Odontology, University of Campinas, São Paulo, Brazil.
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17
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Allen EP, Bayne SC, Becker IM, Donovan TE, Hume WR, Kois JC. Annual review of selected dental literature: report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry. J Prosthet Dent 2000; 84:59-92. [PMID: 10898844 DOI: 10.1067/mpr.2000.107084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- E P Allen
- Department of Periodontics, Baylor College of Dentistry, The Texas A&M University System, Dallas, Texas, USA.
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