Periodontal ligament fibroblasts, preosteoblasts, and prechondrocytes express receptors for epidermal growth factor in vivo: a comparative radioautographic study

Betacellulin in Chronic Periodontitis Patients With and Without Type 2 Diabetes Mellitus: An Immunohistochemical Study

BACKGROUND

The host immune response to bacterial dental plaque determines periodontal disease susceptibility by increasing the secretion of inflammatory cytokines. The Epidermal Growth Factor family cytokines stimulate proliferation and keratinization of cells in dermis and oral epithelium. Epidermal Growth Factor family consists of Amphiregulin, Betacellulin, Epiregulin, Epigen, Heparin binding Epidermal Growth Factor like growth factor and transforming Growth Factor-alpha.

AIM

The current study aimed to investigate expression of Betacellulin in chronic periodontitis patients with and without type 2 diabetes mellitus and thereby assessing role of betacellulin in periodontal health and disease.

MATERIALS AND METHODS

Present study comprised of 90 participants, age ranges from 18 to 60-year-old, for the period of March 2010 to May 2011. Participants were categorized into three groups based Gingival index (GI), probing depth (PD) and clinical attachment loss (CA Loss). Group 1 consisted 30 individuals with clinically healthy periodontium, Group-2 consisted 30 individuals with GI>1, PD≥5 mm, and CA Loss>3 mm. Group-3 (Chronic Periodontitis with type 2 diabetes mellitus) consisted 30 with GI >1, PD≥5 mm, and CA Loss>3 mm. Immunohistochemical localization and quantification of Betacellulin was done in gingival tissue samples from all groups.

RESULTS

Data showed expression of Betacellulin were higher in chronic periodontitis as compared to healthy. A positive correlation found in Betacellulin expression and Probing Depth in chronic periodontitis.

CONCLUSION

This footmark study impacts the role of Betacellulin in pathogenesis and progression of periodontal disease which will help in exploration of novel immunotherapeutic strategies and immunological research activity in this field.

Benign fibro-osseous lesions: a review of current concepts

The benign fibro-osseous lesions (BFOL) represent a clinically diverse group of disorders of bone that share similar histopathologic features. As a group, they are relatively common in the craniofacial complex, especially the jaws. Although the general concept of BFOL is relatively well known, specific diagnostic interpretation of individual cases is often challenging. New concepts and controversies have arisen over the past 10 to 15 years regarding classification and diagnostic criteria. However, among the new theories and contentions, there is now essential agreement that the osseous dysplasias represent a single disease process, while the so-called "juvenile active ossifying fibroma" and other "aggressive," "active," "psammomatoid" ossifying/cementifying fibromas remain controversial. This review is presented to update the surgical pathologist on the various entities comprising the spectrum of BFOL and to examine the criteria for their diagnosis.

Expression of growth-factor receptors in normal and regenerating human periodontal cells

Growth factors are biologically active mediators that bind to specific receptors on target cells and regulate genes involved in cell growth, wound healing and regeneration. The expression of these receptors is thus of fundamental importance for the response of the cells to the factors. The aim here was to examine, using immunohistochemistry and flow cytometry, the expression of growth factor receptors in normal gingiva, periodontal ligament and in cells derived from these tissues, and also in regenerated tissues following guided tissue regeneration (GTR). By immunocytochemistry platelet-derived growth factor receptor-alpha (PDGF-Ralpha) was not detected in any of the tissues, whereas the PDGF-Rbeta and transforming growth factor-beta receptor types I and II (TGF-beta RI, RII) appeared to be upregulated in regenerated tissues compared with gingival and periodontal ligament tissues. Epidermal growth factor receptor (EGF-R) was also notably elevated in the regenerated tissue and was strongly expressed in the gingival epithelium but not in the periodontal ligament. Neither were fibroblast growth factor receptor-I (FGF-RI) or insulin-like growth factor receptor (IGF-R) detected in the periodontal ligament, nor in the gingiva, but they sometimes stained weakly in the regenerated tissues. Flow cytometry (FCM) showed that all the cells derived from the normal gingiva and the periodontal ligament expressed the PDGF-Rbeta, whereas the TGF-beta RI and RII, FGF-RI and IGF-R were detected in only a proportion of the total cells. In contrast, none of the cells expressed the PDGF-Ralpha or the EGF-R. These observations show that the growth factor receptors are differentially expressed by the periodontal tissues and cells and suggest that the corresponding factors may also be differentially involved in periodontal wound healing and regeneration.

Immunohistochemical localization of epidermal growth factor in cat paradental tissues during tooth movement

Epidermal growth factor enhances proliferation and differentiation of cells during growth, maturation, and tissue healing. The objectives were to localize the epidermal growth factor in paradental cells and to determine the effect of orthodontic treatment on its concentrations in periodontal ligament fibroblasts, alveolar bone surface lining cells, and epithelial rests of Malassez. Sixty male cats, 1 year old, were divided into 2 groups: active and sham, and further divided into 10 time groups. In the active group, 1 maxillary canine was retracted by 80 g force; in the sham group, the animals received an inactive appliance. Sagittal sections of each half maxilla were stained for epidermal growth factor; staining intensity was measured microphotometrically in 10 periodontal ligament fibroblasts, alveolar bone surface lining cells, and epithelial rests of Malassez cells in sites of periodontal ligament tension and compression, and in corresponding sites near control and sham canines. The overall mean staining intensity of the cells of the active group animals was 30.47%, whereas that of the sham group was 21.78% (P <.0001). In all 3 types, cells near the actively treated canines stained significantly darker (P <.0001) than cells near the sham or control canines, particularly between 12 hours and 7 days. These results demonstrate that orthodontic forces increase epidermal growth factor concentrations in paradental cells, suggesting that epidermal growth factor participates in the tissue remodeling that facilitates tooth movement.

Signal transduction mechanisms in mesenchymal cells

Mesenchymal cells are continually stimulated by a wide spectrum of biological mediators. These mediators bind to receptors on the cell surface and initiate a cascade of signaling events. The initial signal transduction pathways known to be stimulated in mesenchymal cells included phospholipase C, phospholipase D, phospholipase A2, adenylate cyclase, receptor tyrosine kinases, and receptor serine/threonine kinases. These pathways are reviewed and specific applications for therapeutic intervention in wound healing and regenerative therapy in the periodontium are discussed.

Effects of sialoadenectomy and exogenous EGF on molar drift and orthodontic tooth movement in rats

Effects on bone remodeling have been attributed to epidermal growth factor (EGF). Sialoadenectomy (SX) removes the major source of EGF in rodents and decreases both salivary and serum EGF levels. EGF effects on rat alveolar bone remodeling manifested by molar drift (MD) and orthodontic tooth movement (OTM) were examined using the following two approaches: 1) EGF depletion by SX and replacement by orally administered EGF (50 micrograms.animal-1.day-1); 2) sham rats supplemented with matching amounts of EGF. MD and OTM were measured using cephalometric radiographs; bone formation was measured histomorphometrically using tetracycline labeling. Normal MD was not detected after SX, and alveolar bone formation was significantly reduced both around the tooth and in nondental sites. Replacement EGF given to SX rats and supplemental EGF administered to sham rats changed the direction and enhanced the rate of MD. A mesially directed orthodontic force applied to the molars of SX animals increased bone formation on the distal aspect of the tooth roots. Supplemental EGF did not significantly affect OTM. EGF affects alveolar bone remodeling, as manifested clinically by alterations in normal maxillary MD.

Evidence for up-regulation of epidermal growth-factor receptors on rat periodontal ligament fibroblastic cells associated with stabilization of phenotype in vitro

This study sought to understand the role of epidermal growth factor receptor (EGF-R) in periodontal ligament (PDL) fibroblasts. Rat PDL fibroblastic cells and ROS 17/2.8 cells (highly differentiated osteoblastic osteosarcoma cells) were cultured and treated with transforming growth factor-alpha (TGF-alpha), EGF, dexamethasone (Dex) or a combination of EGF and Dex. Alkaline phosphatase (ALP) activity, an early differentiation marker for mineralized tissue-forming cells, was measured using p-nitrophenylphosphate as a substrate. For Scatchard analysis of [125I]-EGF binding, cells were incubated in Dulbecco's modified Eagle's medium containing 0.2% bovine serum albumin and 0-64 ng/ml of [125I]-EGF for 4 h at 4 degrees C. Also, the synthesis of EGF-R protein and the expression of mRNA for EGF-R were measured by immunoprecipitation and Northern blot analysis, respectively. Untreated PDL fibroblastic cells showed a gradual increase in spontaneous ALP activity from 32.4 U/10(6) cells at 2 days to 49.6 U/10(6) cells at 7 days of culture. ALP activity was further increased to 70.8 U/10(6) cells at 7 days after treatment with Dex, whereas EGF treatment reduced it to 19.4 U/10(6) cells. Culture of PDL fibroblastic cells in the presence of a combination of Dex and EGF decreased the Dex-induced ALP activity from 70.8 U to 41.8 U/10(6) cells at 7 days. A similar inhibitory effect on ALP activity was found after treatment with TGF-alpha. In contrast, ROS cells maintained a high ALP activity (1748 U/10(6) cells) throughout culture, unaffected by EGF. Scatchard analysis demonstrated that PDL fibroblastic cells have both high- and low-affinity forms of EGF-R, while ROS cells did not have any detectable EGF-R. Treatment of PDL cells with Dex for 2 days decreased the synthesis of EGF-R protein, the expression of EGF-R mRNA and the number of EGF-R. In contrast, EGF treatment increased the expression of EGF-R mRNA. These data suggest that PDL fibroblastic cells express numerous EGF-R, but the number decreases during their differentiation into mineralized tissue-forming cells under the influence of Dex. Thus, EGF-R may function in the stabilization of phenotype in PDL fibroblastic cells.

What's new in the role of cytokines on osteoblast proliferation and differentiation?

This review assesses recent data concerning the role of cytokines produced by a variety of cells in bone on osteoblast function. The following themes are presumed: (1) osteoblasts are mesenchymal cells which act as either the major cellular agents of bone formation or as modulators of bone resorption by osteoclasts. The regulation of osteoblast proliferation and differentiation may involve a negative feedback process resulting in phenotype suppression; (2) cytokines including platelet-derived growth factors (PDGF), parathyroid hormone-related proteins (PTHrP), bone morphogenic proteins (BMP), transforming growth factor beta (TGF beta), fibroblast growth factors (FGF), insulin-like growth factors (IGF), epidermal growth factors (EGF), interleukin-1 and 6, tumour necrosis factors (TNF), interferon and haematopoietic growth factors have effects on osteoblast differentiation and proliferation but their effectiveness may not be identical in vitro and in vivo; (3) finally, therapeutic strategies for cytokine use in clinical practice are considered.

Giant ossifying fibroma. Case report on a bimaxillary presentation

Ossifying fibroma is a slow-growing, benign neoplasm, but some lesions behave aggressively, reaching massive proportions, thus demanding special treatment. The following case report holds particular interest, because of the simultaneous occurrence of an active ossifying-cementifying fibroma in the maxilla and mandible with the maxillary lesion attaining enormous size.

Localization of epidermal growth factor receptors in cells of the enamel organ of the rat incisor

Epidermal growth factor (EGF) is a peptide shown to effect precocious incisor tooth eruption in rat pups. Binding sites for EGF were visualized in the continuously erupting adult rat incisor by light and electron microscope radioautography after in vivo injection of 125I-EGF. These binding sites represented EGF receptors because of (i) competition between 125I-EGF binding at 2 min after injection and a coinjected excess of unlabeled EGF; (ii) the receptor-mediated endocytosis of 125I-EGF at 15 and 30 min after injection; and (iii) the demonstration of EGF receptor kinase activation in vivo. The stem and the mitotic cells in the epithelial odontogenic organ at the growing end of the tooth develop into two nondividing layers of the enamel organ: (i) ameloblasts which secrete enamel and are subsequently involved in the enamel maturation process, and (ii) papillary layer cells situated between the blood supply and the ameloblasts. Although few EGF receptors were present at the mitotic end, receptor density was highest at the mature end of the enamel organ. High levels of 125I-EGF binding were found on papillary layer cells and ruffle-ended, but not smooth-ended, ameloblasts. This implies a cyclical exteriorization and internalization of receptors during modulations between the two cell types. These data suggest that the EGF receptor mediates a major function of the enamel organ in the formation of enamel.

Expression of EGF-receptors on epithelial and stromal cells of normal and inflamed gingiva

Immunolocalization techniques were used to examine the expression of the cell surface receptors of EGF in normal and inflamed gingival tissue. Detectable levels of receptor were not observed in any (0/6) of the normal tissue biopsies examined; in contrast, the EGF-receptor was expressed by both epithelial and stromal cells in 7/9 of the inflamed tissue biopsies. Receptor expression by epithelial cells in inflamed tissues exhibited a variable distribution pattern. In the majority of sections, staining was confined to cells in the spinous, granular and cornified cell layers, with little in the basal layer. Occasionally, isolated islands of stained epithelial cells were present, suggesting their clonal origin. Staining for the EGF receptor was also observed in fibroblasts and endothelial cells throughout the lamina propria of inflamed tissue. Positive staining for the receptor ligand (EGF) was observed in both normal and inflamed tissue. These data suggest that an up-regulation of cell surface receptors for EGF occurs during the inflammatory response, this resulting in an increased cellular responsiveness to EGF.

Occurrence of epidermal growth factor-binding sites during differentiation of cementoblasts and periodontal ligament fibroblasts of the young rat: a light and electron microscopic radioautographic study

Occurrence of epidermal growth factor (EGF)-binding sites during differentiation of cementoblasts and periodontal ligament (PDL) fibroblasts was investigated using radioautography after I. V. injection of 125I-EGF to 14-day-old rats. During differentiation of cementoblasts, a very low level of EGF-binding sites was present on the mesenchymal cells in dental follicle proper, precementoblasts, and cementoblasts. On the other hand, during differentiation of PDL fibroblasts, numerous EGF-binding sites were observed on the undifferentiated paravascular cells and on the perifollicular mesenchymes representing the major source of PDL fibroblast precursor cells. Also heavy labeling was observed throughout their differentiation to PDL fibroblasts, as well as during full synthetic activity as mature cells. Quantitative analysis of the light microscopic radioautographs revealed that these cells demonstrated approximately 4 grains per 100 microns 2 of cell area. These results suggest that EGF plays an important role in differentiation of PDL fibroblasts, but not in that of cementoblasts. Furthermore, the well-known in vivo effect of EGF in producing precocious eruption of teeth may be a consequence of a more extensive effect of EGF throughout differentiation of PDL fibroblasts as well as during full synthetic activity as mature cells.

Role of fibroblast subpopulations in periodontal physiology and pathology

Fibroblasts are the principal cell type in the soft connective tissues of the periodontium; they perform important functions in development, physiology, and disease. A growing number of reports have indicated site-specific phenotypic variation of fibroblasts. Heterogeneity of metabolic traits has been demonstrated in cells from healthy and diseased tissues. The tissue distribution and relative proportions of fibroblast subpopulations have a significant impact on the regulation of connective tissue function in health and disease.

Ossifying fibroma of the mandible and maxilla: review of 18 cases

A clinical, radiographic, histologic and follow up study of 18 cases of ossifying fibroma involving the mandible and maxilla was performed. Differences in behavior and management according to age, location, radiographic appearance and histopathology were not evident. A wide range of microscopic findings within and between cases was evident, while the radiographic finding consisting of sharp delineation was consistent in all cases. The presence or absence of cementum or cementum-like material and various types of formed elements was likewise of little clinical significance. Finally, a potential source of the neoplastic cell from the periodontal apparatus may help explain the range of histologic findings.