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Brian L. Foster - One of the best experts on this subject based on the ideXlab platform.
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On the discovery of Cementum.
Journal of periodontal research, 2017Co-Authors: Brian L. FosterAbstract:Though Cementum of the tooth root is critical for periodontal structure and tooth attachment and function, this tissue was not discovered and characterized on human teeth until a full century later than enamel and dentin. Early observations from the seventeenth to the nineteenth centuries by Marcello Malpighi, Antonie van Leeuwenhoek, Robert Blake, Jacques Tenon and Georges Cuvier founded a confusing and conflicting nomenclature that obscured the nature of Cementum, often conflating it with bone. Advances in microscopy and histological procedures yielded the first detailed descriptions of human Cementum in the 1830s by Jan Purkinje and Anders Retzius, who identified for the first time acellular and cellular types of Cementum, and the resident cementocytes embedded in the latter. Comparative anatomy studies by Richard Owen and others over the latter half of the nineteenth century identified coronal and radicular Cementum varieties across the Reptilia and Mammalia. The functional importance of Cementum was not appreciated until detailed anatomical studies of the periodontium were performed by G.V. Black and others in the late nineteenth and early twentieth centuries. These early studies on Cementum laid the foundation for more advanced understanding of Cementum ultrastructure, composition, development, physiology, disease, genetics, repair and regeneration throughout the twentieth and into the twenty-first century.
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Counter-regulatory phosphatases TNAP and NPP1 temporally regulate tooth root cementogenesis
International Journal of Oral Science, 2015Co-Authors: Laura E Zweifler, Martha J. Somerman, Mudita K Patel, Helen F Wimer, Jose Luis Millan, Francisco H.umberto Nociti, Brian L. FosterAbstract:Cementum is critical for anchoring the insertion of periodontal ligament fibers to the tooth root. Several aspects of cementogenesis remain unclear, including differences between acellular Cementum and cellular Cementum, and between Cementum and bone. Biomineralization is regulated by the ratio of inorganic phosphate (P_i) to mineral inhibitor pyrophosphate (PP_i), where local P_i and PP_i concentrations are controlled by phosphatases including tissue-nonspecific alkaline phosphatase (TNAP) and ectonucleotide pyrophosphatase/phosphodiesterase 1 (NPP1). The focus of this study was to define the roles of these phosphatases in cementogenesis. TNAP was associated with earliest cementoblasts near forming acellular and cellular Cementum. With loss of TNAP in the Alpl null mouse, acellular Cementum was inhibited, while cellular Cementum production increased, albeit as hypomineralized cementoid. In contrast, NPP1 was detected in cementoblasts after acellular Cementum formation, and at low levels around cellular Cementum. Loss of NPP1 in the Enpp1 null mouse increased acellular Cementum, with little effect on cellular Cementum. Developmental patterns were recapitulated in a mouse model for acellular Cementum regeneration, with early TNAP expression and later NPP1 expression. In vitro , cementoblasts expressed Alpl gene/protein early, whereas Enpp1 gene/protein expression was significantly induced only under mineralization conditions. These patterns were confirmed in human teeth, including widespread TNAP, and NPP1 restricted to cementoblasts lining acellular Cementum. These studies suggest that early TNAP expression creates a low PP_i environment promoting acellular Cementum initiation, while later NPP1 expression increases PP_i, restricting acellular Cementum apposition. Alterations in PP_i have little effect on cellular Cementum formation, though matrix mineralization is affected. The timing and site of action of two key enzymes help regulate the formation of Cementum, one of the mineralized substances of teeth. An international team led by Brian Foster from the US National Institute of Arthritis and Musculoskeletal and Skin Diseases considered the roles of two enzymes — tissue non-specific phosphatase (TNAP) and ectonucleotide pyrophosphatase/phosphodiesterase 1 (NPP1) — in Cementum development. They showed in mice that early TNAP expression created a particular environment in teeth with low levels of pyrophosphate, a mineral inhibitor. This promoted the creation of a type of Cementum that does not incorporate cells into its structure. Later on in development, the expression of NPP1 boosted levels of pyrophosphate, which restricted this type of Cementum. These enzymes had little effect on Cementum containing cells. The researchers confirmed these patterns in extracted human teeth.
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Methods for studying tooth root Cementum by light microscopy.
International journal of oral science, 2012Co-Authors: Brian L. FosterAbstract:The tooth root Cementum is a thin, mineralized tissue covering the root dentin that is present primarily as acellular Cementum on the cervical root and cellular Cementum covering the apical root. While Cementum shares many properties in common with bone and dentin, it is a unique mineralized tissue and acellular Cementum is critical for attachment of the tooth to the surrounding periodontal ligament (PDL). Resources for methodologies for hard tissues often overlook Cementum and approaches that may be of value for studying this tissue. To address this issue, this report offers detailed methodology, as well as comparisons of several histological and immunohistochemical stains available for imaging the Cementum–PDL complex by light microscopy. Notably, the infrequently used Alcian blue stain with nuclear fast red counterstain provided utility in imaging Cementum in mouse, porcine and human teeth. While no truly unique extracellular matrix markers have been identified to differentiate Cementum from the other hard tissues, immunohistochemistry for detection of bone sialoprotein (BSP), osteopontin (OPN), and dentin matrix protein 1 (DMP1) is a reliable approach for studying both acellular and cellular Cementum and providing insight into developmental biology of these tissues. Histological and immunohistochemical approaches provide insight on developmental biology of Cementum.
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Methods for studying tooth root Cementum by light microscopy
International Journal of Oral Science, 2012Co-Authors: Brian L. FosterAbstract:The tooth root Cementum is a thin, mineralized tissue covering the root dentin that is present primarily as acellular Cementum on the cervical root and cellular Cementum covering the apical root. While Cementum shares many properties in common with bone and dentin, it is a unique mineralized tissue and acellular Cementum is critical for attachment of the tooth to the surrounding periodontal ligament (PDL). Resources for methodologies for hard tissues often overlook Cementum and approaches that may be of value for studying this tissue. To address this issue, this report offers detailed methodology, as well as comparisons of several histological and immunohistochemical stains available for imaging the Cementum–PDL complex by light microscopy. Notably, the infrequently used Alcian blue stain with nuclear fast red counterstain provided utility in imaging Cementum in mouse, porcine and human teeth. While no truly unique extracellular matrix markers have been identified to differentiate Cementum from the other hard tissues, immunohistochemistry for detection of bone sialoprotein (BSP), osteopontin (OPN), and dentin matrix protein 1 (DMP1) is a reliable approach for studying both acellular and cellular Cementum and providing insight into developmental biology of these tissues. Histological and immunohistochemical approaches provide insight on developmental biology of Cementum. Light microscopy and chemical staining methods could help clarify how tooth Cementum develops, a US scientist reveals. This thin layer of mineralized tissue that covers the roots of teeth can be one of two types: acellular or cellular. Since little is known about the tissue itself, Brian Foster of the National Institutes of Health, Maryland, USA, compared different staining techniques to differentiate acellular and cellular Cementum from surrounding dentin, bone and ligament structures in mouse, porcine and human teeth. He found that Alcian blue stain and nuclear fast red counterstain were the most effective in distinguishing between Cementum and surrounding tissues using light microscopy. Foster also found that using antibodies to highlight specific proteins in the tissue (immunohistochemistry) helped visualize the Cementum layers and could provide insight into its biological development.
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The Progressive Ankylosis Protein Regulates Cementum Apposition and Extracellular Matrix Composition
Cells Tissues Organs, 2011Co-Authors: Brian L. Foster, Kanako J. Nagatomo, S.o. Bamashmous, K.a. Tompkins, Catherine A Guenther, David M. Kingsley, D. Dunn, Hanson Fong, R B RutherfordAbstract:Background/Aims: Tooth root Cementum is sensitive to modulation of inorganic pyrophosphate (PPi), an inhibitor of hydroxyapatite precipitation. Factors increasing PPi include progressive ankylosis protein (ANK) and ectonucleotide pyrophosphatase/phosphodiesterase 1 (NPP1) while tissue nonspecific alkaline phosphatase hydrolyzes PPi. Studies here aimed to define the role of ANK in root and Cementum by analyzing tooth development in Ank knock-out (KO) mice versus wild type. Materials and Methods: Periodontal development in KO versus control mice was analyzed by histology, histomorphometry, immunohistochemistry, in situ hybridization, electron microscopy, and nanoindentation. Cementoblast cultures were used in vitro to provide mechanistic underpinnings for PPi modulation of cell function. Results: Over the course of root development, Ank KO cervical Cementum became 8- to 12-fold thicker than control cervical Cementum. Periodontal ligament width was maintained and other dentoalveolar tissues, including apical Cementum, were unaltered. Cervical Cementum uncharacteristically included numerous cells, from rapid cementogenesis. Ank KO increased osteopontin and dentin matrix protein 1 gene and protein expression, and markedly increased NPP1 protein expression in cementoblasts but not in other cell types. Conditional ablation of Ank in joints and periodontia confirmed a local role for ANK in cementogenesis. In vitro studies employing cementoblasts indicated that Ank and Enpp1 mRNA levels increased in step with mineral nodule formation, supporting a role for these factors in regulation of Cementum matrix mineralization. Conclusion: ANK, by modulating local PPi, controls cervical Cementum apposition and extracellular matrix. Loss of ANK created a local environment conducive to rapid cementogenesis; therefore, approaches modulating PPi in periodontal tissues have potential to promote Cementum regeneration.
Pishan Yang - One of the best experts on this subject based on the ideXlab platform.
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effects of conservatively treated diseased Cementum with or without emd on in vitro cementoblast differentiation and in vivo Cementum like tissue formation of human periodontal ligament cells
Cell Proliferation, 2014Co-Authors: Wei Feng, Aimei Song, Jun Cai, Qinfeng Sun, Pishan YangAbstract:Objectives The present study aimed to evaluate the effects of conservatively treated diseased Cementum on in vitro cementoblast differentiation and in vivo Cementum-like tissue formation of human periodontal ligament cells (hPDLCs), and observe differential effects of enamel matrix derivative (EMD) on in vivo Cementum formation by hPDLCs. Materials and methods Forty-eight Cementum slices and 48 dentin slices were prepared from periodontitis compromised teeth, and hPDLCs were inoculated on to all root slices. Twenty-four co-cultured root slices of each group were used for mRNA expression of Cementum attachment protein and CEMP1. With application of EMD, 24 co-cultured root slices (divided into groups C, D, C+E, D+E) were transplanted subcutaneously into nude mice. All root fragments were reviewed by histological analysis and immunohistochemical staining for bone sialoprotein. Results mRNA expressions of Cementum attachment protein and Cementum protein - 1 from hPDLCs on Cementum slices were statistically higher than those of dentin slices. Seven specimens of group C and 10 specimens of group C+E revealed a layer of Cementum-like tissue (NFC) on surfaces of pre-existing Cementum. NFC was thicker in group C+E than in group C. All NFCs were positively stained for bone sialoprotein, however, there was no NFC formation on dentin slices. Conclusion Conservatively treated diseased Cementum promoted in vitro cementoblast differentiation and in vivo Cementum-like tissue formation by hPDLCs, and the in vivo effect was enhanced by the presence of EMD.
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Effects of conservatively treated diseased Cementum with or without EMD on in vitro cementoblast differentiation and in vivo Cementum‐like tissue formation of human periodontal ligament cells
Cell proliferation, 2014Co-Authors: Wei Feng, Aimei Song, Jun Cai, Qinfeng Sun, Pishan YangAbstract:Objectives The present study aimed to evaluate the effects of conservatively treated diseased Cementum on in vitro cementoblast differentiation and in vivo Cementum-like tissue formation of human periodontal ligament cells (hPDLCs), and observe differential effects of enamel matrix derivative (EMD) on in vivo Cementum formation by hPDLCs. Materials and methods Forty-eight Cementum slices and 48 dentin slices were prepared from periodontitis compromised teeth, and hPDLCs were inoculated on to all root slices. Twenty-four co-cultured root slices of each group were used for mRNA expression of Cementum attachment protein and CEMP1. With application of EMD, 24 co-cultured root slices (divided into groups C, D, C+E, D+E) were transplanted subcutaneously into nude mice. All root fragments were reviewed by histological analysis and immunohistochemical staining for bone sialoprotein. Results mRNA expressions of Cementum attachment protein and Cementum protein - 1 from hPDLCs on Cementum slices were statistically higher than those of dentin slices. Seven specimens of group C and 10 specimens of group C+E revealed a layer of Cementum-like tissue (NFC) on surfaces of pre-existing Cementum. NFC was thicker in group C+E than in group C. All NFCs were positively stained for bone sialoprotein, however, there was no NFC formation on dentin slices. Conclusion Conservatively treated diseased Cementum promoted in vitro cementoblast differentiation and in vivo Cementum-like tissue formation by hPDLCs, and the in vivo effect was enhanced by the presence of EMD.
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pre existing root Cementum may promote cementoblast differentiation of human periodontal ligament cells
Cell Proliferation, 2012Co-Authors: Aimei Song, Jun Cai, Keqing Pan, Pishan YangAbstract:Objectives To observe whether preserved healthy Cementum could promote differentiation of human periodontal ligament cells to cementoblasts. Materials and methods Symmetrical root slices from each healthy premolar were distributed into either the control group (Cementum removed) or test group (Cementum preserved). After isolation and characterization, human periodontal ligament cells were inoculated onto root slices for 7 days co-culture. Two slices per group were studied for cell morphology by scanning electronic microscopy. Twenty-three slices were detected for expression of Cementum attachment protein and Cementum protein 23, two putative cementoblast markers, by real-time polymerase chain reaction. Twenty slices were transplanted into nude mice and analysed using histology and immunohistochemistry for osteopontin and bone sialoprotein expression after 8 weeks. Results Cells of the test group had smoother fibroblast morphology and higher Cementum protein 23 and Cementum attachment protein expression than those of the control group (P < 0.01). In the test group, 14 root slices revealed Cementum-like matrix formation resting on old Cementum; no splits were observed between newly formed matrix and old Cementum. In the control group, 17 specimens had fibrous tissue formation along the root surface and varying width of splits could be seen between new fibrous tissue and dentine surface. Only three specimens demonstrated presence of newly formed thin Cementum-like matrix. Newly formed Cementum-like matrix was positive for osteopontin and bone sialoprotein. Conclusions The results demonstrate that healthy root Cementum may promote differentiation of human periodontal ligament cells towards cementoblasts.
Jun Cai - One of the best experts on this subject based on the ideXlab platform.
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effects of conservatively treated diseased Cementum with or without emd on in vitro cementoblast differentiation and in vivo Cementum like tissue formation of human periodontal ligament cells
Cell Proliferation, 2014Co-Authors: Wei Feng, Aimei Song, Jun Cai, Qinfeng Sun, Pishan YangAbstract:Objectives The present study aimed to evaluate the effects of conservatively treated diseased Cementum on in vitro cementoblast differentiation and in vivo Cementum-like tissue formation of human periodontal ligament cells (hPDLCs), and observe differential effects of enamel matrix derivative (EMD) on in vivo Cementum formation by hPDLCs. Materials and methods Forty-eight Cementum slices and 48 dentin slices were prepared from periodontitis compromised teeth, and hPDLCs were inoculated on to all root slices. Twenty-four co-cultured root slices of each group were used for mRNA expression of Cementum attachment protein and CEMP1. With application of EMD, 24 co-cultured root slices (divided into groups C, D, C+E, D+E) were transplanted subcutaneously into nude mice. All root fragments were reviewed by histological analysis and immunohistochemical staining for bone sialoprotein. Results mRNA expressions of Cementum attachment protein and Cementum protein - 1 from hPDLCs on Cementum slices were statistically higher than those of dentin slices. Seven specimens of group C and 10 specimens of group C+E revealed a layer of Cementum-like tissue (NFC) on surfaces of pre-existing Cementum. NFC was thicker in group C+E than in group C. All NFCs were positively stained for bone sialoprotein, however, there was no NFC formation on dentin slices. Conclusion Conservatively treated diseased Cementum promoted in vitro cementoblast differentiation and in vivo Cementum-like tissue formation by hPDLCs, and the in vivo effect was enhanced by the presence of EMD.
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Effects of conservatively treated diseased Cementum with or without EMD on in vitro cementoblast differentiation and in vivo Cementum‐like tissue formation of human periodontal ligament cells
Cell proliferation, 2014Co-Authors: Wei Feng, Aimei Song, Jun Cai, Qinfeng Sun, Pishan YangAbstract:Objectives The present study aimed to evaluate the effects of conservatively treated diseased Cementum on in vitro cementoblast differentiation and in vivo Cementum-like tissue formation of human periodontal ligament cells (hPDLCs), and observe differential effects of enamel matrix derivative (EMD) on in vivo Cementum formation by hPDLCs. Materials and methods Forty-eight Cementum slices and 48 dentin slices were prepared from periodontitis compromised teeth, and hPDLCs were inoculated on to all root slices. Twenty-four co-cultured root slices of each group were used for mRNA expression of Cementum attachment protein and CEMP1. With application of EMD, 24 co-cultured root slices (divided into groups C, D, C+E, D+E) were transplanted subcutaneously into nude mice. All root fragments were reviewed by histological analysis and immunohistochemical staining for bone sialoprotein. Results mRNA expressions of Cementum attachment protein and Cementum protein - 1 from hPDLCs on Cementum slices were statistically higher than those of dentin slices. Seven specimens of group C and 10 specimens of group C+E revealed a layer of Cementum-like tissue (NFC) on surfaces of pre-existing Cementum. NFC was thicker in group C+E than in group C. All NFCs were positively stained for bone sialoprotein, however, there was no NFC formation on dentin slices. Conclusion Conservatively treated diseased Cementum promoted in vitro cementoblast differentiation and in vivo Cementum-like tissue formation by hPDLCs, and the in vivo effect was enhanced by the presence of EMD.
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pre existing root Cementum may promote cementoblast differentiation of human periodontal ligament cells
Cell Proliferation, 2012Co-Authors: Aimei Song, Jun Cai, Keqing Pan, Pishan YangAbstract:Objectives To observe whether preserved healthy Cementum could promote differentiation of human periodontal ligament cells to cementoblasts. Materials and methods Symmetrical root slices from each healthy premolar were distributed into either the control group (Cementum removed) or test group (Cementum preserved). After isolation and characterization, human periodontal ligament cells were inoculated onto root slices for 7 days co-culture. Two slices per group were studied for cell morphology by scanning electronic microscopy. Twenty-three slices were detected for expression of Cementum attachment protein and Cementum protein 23, two putative cementoblast markers, by real-time polymerase chain reaction. Twenty slices were transplanted into nude mice and analysed using histology and immunohistochemistry for osteopontin and bone sialoprotein expression after 8 weeks. Results Cells of the test group had smoother fibroblast morphology and higher Cementum protein 23 and Cementum attachment protein expression than those of the control group (P < 0.01). In the test group, 14 root slices revealed Cementum-like matrix formation resting on old Cementum; no splits were observed between newly formed matrix and old Cementum. In the control group, 17 specimens had fibrous tissue formation along the root surface and varying width of splits could be seen between new fibrous tissue and dentine surface. Only three specimens demonstrated presence of newly formed thin Cementum-like matrix. Newly formed Cementum-like matrix was positive for osteopontin and bone sialoprotein. Conclusions The results demonstrate that healthy root Cementum may promote differentiation of human periodontal ligament cells towards cementoblasts.
Aimei Song - One of the best experts on this subject based on the ideXlab platform.
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effects of conservatively treated diseased Cementum with or without emd on in vitro cementoblast differentiation and in vivo Cementum like tissue formation of human periodontal ligament cells
Cell Proliferation, 2014Co-Authors: Wei Feng, Aimei Song, Jun Cai, Qinfeng Sun, Pishan YangAbstract:Objectives The present study aimed to evaluate the effects of conservatively treated diseased Cementum on in vitro cementoblast differentiation and in vivo Cementum-like tissue formation of human periodontal ligament cells (hPDLCs), and observe differential effects of enamel matrix derivative (EMD) on in vivo Cementum formation by hPDLCs. Materials and methods Forty-eight Cementum slices and 48 dentin slices were prepared from periodontitis compromised teeth, and hPDLCs were inoculated on to all root slices. Twenty-four co-cultured root slices of each group were used for mRNA expression of Cementum attachment protein and CEMP1. With application of EMD, 24 co-cultured root slices (divided into groups C, D, C+E, D+E) were transplanted subcutaneously into nude mice. All root fragments were reviewed by histological analysis and immunohistochemical staining for bone sialoprotein. Results mRNA expressions of Cementum attachment protein and Cementum protein - 1 from hPDLCs on Cementum slices were statistically higher than those of dentin slices. Seven specimens of group C and 10 specimens of group C+E revealed a layer of Cementum-like tissue (NFC) on surfaces of pre-existing Cementum. NFC was thicker in group C+E than in group C. All NFCs were positively stained for bone sialoprotein, however, there was no NFC formation on dentin slices. Conclusion Conservatively treated diseased Cementum promoted in vitro cementoblast differentiation and in vivo Cementum-like tissue formation by hPDLCs, and the in vivo effect was enhanced by the presence of EMD.
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Effects of conservatively treated diseased Cementum with or without EMD on in vitro cementoblast differentiation and in vivo Cementum‐like tissue formation of human periodontal ligament cells
Cell proliferation, 2014Co-Authors: Wei Feng, Aimei Song, Jun Cai, Qinfeng Sun, Pishan YangAbstract:Objectives The present study aimed to evaluate the effects of conservatively treated diseased Cementum on in vitro cementoblast differentiation and in vivo Cementum-like tissue formation of human periodontal ligament cells (hPDLCs), and observe differential effects of enamel matrix derivative (EMD) on in vivo Cementum formation by hPDLCs. Materials and methods Forty-eight Cementum slices and 48 dentin slices were prepared from periodontitis compromised teeth, and hPDLCs were inoculated on to all root slices. Twenty-four co-cultured root slices of each group were used for mRNA expression of Cementum attachment protein and CEMP1. With application of EMD, 24 co-cultured root slices (divided into groups C, D, C+E, D+E) were transplanted subcutaneously into nude mice. All root fragments were reviewed by histological analysis and immunohistochemical staining for bone sialoprotein. Results mRNA expressions of Cementum attachment protein and Cementum protein - 1 from hPDLCs on Cementum slices were statistically higher than those of dentin slices. Seven specimens of group C and 10 specimens of group C+E revealed a layer of Cementum-like tissue (NFC) on surfaces of pre-existing Cementum. NFC was thicker in group C+E than in group C. All NFCs were positively stained for bone sialoprotein, however, there was no NFC formation on dentin slices. Conclusion Conservatively treated diseased Cementum promoted in vitro cementoblast differentiation and in vivo Cementum-like tissue formation by hPDLCs, and the in vivo effect was enhanced by the presence of EMD.
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pre existing root Cementum may promote cementoblast differentiation of human periodontal ligament cells
Cell Proliferation, 2012Co-Authors: Aimei Song, Jun Cai, Keqing Pan, Pishan YangAbstract:Objectives To observe whether preserved healthy Cementum could promote differentiation of human periodontal ligament cells to cementoblasts. Materials and methods Symmetrical root slices from each healthy premolar were distributed into either the control group (Cementum removed) or test group (Cementum preserved). After isolation and characterization, human periodontal ligament cells were inoculated onto root slices for 7 days co-culture. Two slices per group were studied for cell morphology by scanning electronic microscopy. Twenty-three slices were detected for expression of Cementum attachment protein and Cementum protein 23, two putative cementoblast markers, by real-time polymerase chain reaction. Twenty slices were transplanted into nude mice and analysed using histology and immunohistochemistry for osteopontin and bone sialoprotein expression after 8 weeks. Results Cells of the test group had smoother fibroblast morphology and higher Cementum protein 23 and Cementum attachment protein expression than those of the control group (P < 0.01). In the test group, 14 root slices revealed Cementum-like matrix formation resting on old Cementum; no splits were observed between newly formed matrix and old Cementum. In the control group, 17 specimens had fibrous tissue formation along the root surface and varying width of splits could be seen between new fibrous tissue and dentine surface. Only three specimens demonstrated presence of newly formed thin Cementum-like matrix. Newly formed Cementum-like matrix was positive for osteopontin and bone sialoprotein. Conclusions The results demonstrate that healthy root Cementum may promote differentiation of human periodontal ligament cells towards cementoblasts.
Francis J. Hughes - One of the best experts on this subject based on the ideXlab platform.
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The modulatory role of Cementum matrix on osteoblastic cells in vitro
Journal of Periodontal Research, 1997Co-Authors: D Tenorio, D M Foyle, Francis J. HughesAbstract:The formation of new Cementum is an important issue in clinical periodontology, as Cementum is required to provide attachment for newly formed periodontal tissues to the root surface. In this study a model of cementogenesis in vitro was used in order to test the effects of root surface demineralization on the migration, attachment and formation of a Cementum-like tissue by osteoblastic cells cultured on Cementum and to test the specificity of Cementum matrix in modulating those effects by comparison of root co-cultures with bone co-cultures. It was demonstrated that root surface demineralization did not significantly alter the orientation, number and attachment of cells to the root co-cultures. The results also demonstrated that Cementum and bone matrix appear to behave differently in culture, as seen by their distinct action on the morphological profile of the attached cells and the extracellular matrix deposited by these cells. These results demonstrate that although Cementum matrix appears to stimulate the production of Cementum-like tissue, this action is not confined to Cementum matrix alone, since a similar material was also deposited on dentine and bone surfaces. Thus, these results do not support a specific action of Cementum matrix on the modulation of the cementoblast phenotype. The use of co-cultures of neonatal rat calvaria cells with root slices represents a promising model of cementogenesis in vitro; however, studies should be undertaken towards the indentification of markers to distinguish between cementoblast and osteoblast phenotypes in order to further validate this model.
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Immunocytochemical investigation of the rat cementoblast phenotype
Journal of Periodontal Research, 1993Co-Authors: D Tenorio, A Cruchley, Francis J. HughesAbstract:Recent studies have suggested that cementoblasts may be derived from osteoblast progenitor cells, although the cementoblast phenotype has not been extensively characterized. This immunocytochemical study was carried out to investigate the expression by rat cementoblasts of a number of proteins which are characteristic of the osteoblast phenotype. Paraffin sections from developing rat tooth germs and from fully formed adult rat teeth with surrounding tissues, were incubated with antibodies to type I & III collagen, osteocalcin, transforming growth factor beta (TGE beta), and insulin-like growth factor 1 (IGF1). Frozen sections and unfixed resin-embedded sections were stained for alkaline phosphatase activity. Cementum and bone matrix were strongly positive for type I collagen, although there was only weak staining for type III collagen. Cementum was also positive for osteocalcin, which was particularly strong in the matrix of acellular Cementum. Most osteoblasts and cementoblasts of the cellular Cementum showed intense staining for TGF beta and IGF1, although some cementocytes and osteocytes were negatively stained. The osteoblast- specific anti-E11 mAb reacted strongly with cementoblasts and newly formed cementocytes in the cellular Cementum. Cells associated with acellular Cementum did not express TGF beta, IGF1 or stain positively with anti-E11 antibody at any time during root development. Cementoblasts were weakly or negatively stained for alkaline phosphatase in contrast to the osteoblasts examined, which may reflect the low level of synthetic activity in cementoblasts. These results demonstrate that osteoblasts and cementoblasts of cellular Cementum share many phenotypic characteristics, and also suggest that there may be phenotypic differences between cementoblasts associated with cellular and acellular Cementum.