Overgrown Gingival Tissue Research Articles

Follicular dendritic cell-secreted protein gene expression is upregulated and spread in nifedipine-induced gingival overgrowth.

Follicular dendritic cell-secreted protein (FDC-SP) is secreted protein expressed in follicular dendritic cells, periodontal ligament and junctional epithelium (JE). Its expression could be controlled during inflammatory process of gingiva; however, responsible mechanism for gingival overgrowth and involvement of FDC-SP in clinical condition is still unclear. We hypothesized that JE-specific genes are associated with the initiation of drug-induced gingival enlargement (DIGE) called gingival overgrowth, and investigated the changes of JE-specific gene's expression and their localization in overgrown gingiva from the patients. Immunohistochemical analysis revealed that the FDC-SP localization was spread in overgrown gingival tissues. FDC-SP mRNA levels in GE1 and Ca9-22 cells were increased by time-dependent nifedipine treatments, similar to other JE-specific genes, such as Amelotin (Amtn) and Lamininβ3 subunit (Lamβ3), whereas type 4 collagen (Col4) mRNA levels were decreased. Immunocytochemical analysis showed that FDC-SP, AMTN, and Lamβ3 protein levels were increased in GE1 and Ca9-22 cells. Transient transfection analyses were performed using luciferase constructs including various lengths of human FDC-SP gene promoter, nifedipine increased luciferase activities of -345 and -948FDC-SP constructs. These results raise the possibility that the nifedipine-induced FDC-SP may be related to the mechanism responsible for gingival overgrowth does not occur at edentulous jaw ridges.

Immunolocalization of Bcl-2 oncoprotein in amlodipine-induced gingival overgrowth

Drug-induced gingival overgrowth (DIGO) is one of the unwanted side effects of amlodipine therapy, but the pathogenesis still remains unclear. Apoptosis, which plays a ubiquitous role in tissue homeostasis, including gingiva, may be involved in the development of gingival enlargement. (i) To study the distribution of Bcl-2 in healthy and overgrown gingival tissues. (ii) To compare and correlate the Bcl-2 expression in gingival samples from subjects on amlodipine therapy to the findings in healthy controls. A total of 25 subjects were recruited for the study - 15 hypertensive patients and 10 systemically healthy subjects. Both the groups were analyzed for Bcl-2 expression using immunohistochemistry. Few of the control specimens showed weak positivity to Bcl-2 antibody, with the distribution limited to the basal cell layers alone, whereas 10 hyperplastic specimens expressed Bcl-2 and, unlike the control group, the distribution pattern was seen in both basal and suprabasal layers. The results indicate that the pathogenesis of amlodipine-induced gingival overgrowth might involve inhibition of apoptosis, especially with morphogenesis of hyperplastic gingival epithelia.

Drug‐induced gingival enlargement: Biofilm control and surgical therapy with gallium–aluminum–arsenide (GaAlAs) diode laser—A 2‐year follow‐up

Drug-induced gingival enlargement has been reported in patients treated with various types of anticonvulsant drugs, and is generally associated with the presence of plaque, gingival inflammation, and a genetic predisposition. Effective treatment includes daily oral hygiene and periodic professional prophylaxis. However, in some patients, surgical removal of the gingival tissue overgrowth becomes necessary. The patient in this case report was mentally impaired and had severe drug-induced gingival enlargement. This report describes the initial protocol, the gingivectomy, and a 2-year follow-up. A diode laser was used as an effective and safe method to remove the patient's overgrown gingival tissue.

Effect of tranilast on matrix metalloproteinase-1 secretion from human gingival fibroblasts in vitro.

Some drugs such as phenytoin, calcium blockers, or cyclosporins are known to cause gingival fibrous hyperplasia, an unwanted side effect. Decreased collagen catabolism in overgrown gingival tissue has been proposed as one of the reasons causing the disease. The effect of tranilast, which suppresses collagen synthesis and cell proliferation, on matrix metalloproteinase (MMP-1) secretion from human gingival fibroblast, was studied in vitro. Human gingival fibroblasts were cultured from specimens taken from healthy, periodontal, and overgrown gingival tissues. The effects of tranilast on cell proliferation and MMP-1 secretion from gingival fibroblast were assessed. Inhibitory effect of transforming growth factor (TGF)-beta secretion from gingival fibroblast by tranilast was also evaluated. Tranilast did not interfere with cell proliferation at the low concentrations. MMP-1 concentration significantly increased at the lower doses of tranilast up to about 2-fold compared to controls (P < 0.05). In contrast, higher doses of tranilast significantly decreased activity to 30% and 20%, respectively. MMP-1 secretion was inhibited significantly by phenytoin, nifedipine, and cyclosporin A and the depressed MMP-1 recovered to the control level with tranilast. The amount of secretion from normal and periodontitis gingival fibroblast specimens did not differ, but that from the overgrown gingiva was significantly less than the other types. Moreover, TGF-beta secretion was significantly inhibited by 300 microM of tranilast. Tranilast upregulates the expression of type 1 collagenase suppressed by gingival overgrowth-inducing drugs, and inhibits TGF-beta secretion from gingival fibroblasts. Therefore, tranilast could be considered as an agent for controlling gingival over-growth.

Regulation of keratinocyte growth factor and scatter factor in cyclosporin-induced gingival overgrowth.

Epithelial proliferation is a histological characteristic of drug-induced gingival overgrowth. Keratinocyte growth factor (KGF) and scatter factor (SF) are fibroblast-derived growth factors with potent mitogenic and motogenic effects on epithelial cells, and, therefore, could be involved in the pathogenesis of gingival overgrowth. The aims of this study were to investigate: (i) the effects of cyclosporin on KGF and SF expression by gingival fibroblasts; and (ii) the expression levels of KGF and SF mRNA in normal and overgrown gingival tissue. The KGF and SF protein production was determined by enzyme-linked immunosorbent assay. Relative levels of KGF and SF mRNA expression were determined using semi-quantitative reverse transcriptase polymerase chain reaction. Expression levels in biopsies of normal and overgrown gum were also determined. In overgrown fibroblasts, 500 ng/ml cyclosporin significantly inhibited KGF and SF mRNA and protein while 2000 ng/ml cyclosporin induced a stimulatory effect. In normal cells cyclosporin significantly increased both KGF and SF. KGF and SF mRNA was detected in both normal and overgrown tissues with a tendency towards increased expression levels in overgrown tissue. These results suggest that KGF and SF may have an important role in cyclosporin-induced gingival overgrowth.

Immunohistochemical analysis of epidermal growth factor receptor in cyclosporin A-induced gingival overgrowth

Cyclosporin A (CsA)-induced gingival overgrowth represents a tissue of fibrosis and epidermal growth factor (EGF) has been shown to induce extracellular matrix synthesis by fibroblasts. The purpose of this study was to evaluate the expression of EGF-receptor (EGF-r) in frozen sections of CsA-induced overgrown gingival tissue using immunohistochemical and semiquantitative techniques. Gingival biopsies were obtained from 12 renal transplant patients receiving CsA as well as 9 systemically and periodontally healthy individuals. Immunohistochemical staining procedures were carried out in frozen sections of gingival tissue and the expression of EGF-r was compared between the two study groups. The expression of EGF-r was more pronounced in the oral gingival epithelium of CsA-induced overgrown gingiva as compared to those of the clinically healthy gingival specimens. The reactivity in the inflammatory infiltrate and connective tissue cells of both of the study groups was similar. In conclusion, the results of the present study may suggest that CsA affects EGF-r metabolism in gingival keratinocytes resulting in an increased number of cell surface receptors, which may eventually play a role in the pathogenesis of gingival tissue alterations.

Cyclosporin A regulates interleukin-1beta and interleukin-6 expression in gingiva: implications for gingival overgrowth.

Gingival overgrowth is a common side effect following the administration of cyclosporin A (CsA); however, the cellular mechanisms remain poorly understood. CsA's immunosuppressant properties involve the regulation of synthesis and cellular response to cytokines. A CsA-induced alteration in the cytokine profile within gingival tissue could provide a mechanism for gingival hyperplasia. The aim of this study was to investigate the effects of CsA on the production of 2 cytokines - interleukin-1beta (IL-1beta) and interleukin-6 (IL-6) - by both gingival fibroblasts and peripheral blood mononuclear cells (PBMC). Cells were stimulated for 24 hours in the presence of CsA over a concentration range of 100 to 2,000 ng/ml and the resultant cytokine production determined by ELISA. In addition, levels of both cytokines within normal, inflamed, and overgrown gingival tissue were determined. CsA inhibited IL-6 production by gingival fibroblasts in a dose-dependent manner. In contrast, at a concentration of 2,000 ng/ml, CsA stimulated IL-6 production by PBMC (P <0.05). Fibroblasts derived from overgrown gingiva produced significantly higher levels of IL-6 than their normal counterparts (P <0.05). CsA inhibited IL-1beta production by PBMC over the whole concentration range (P <0.05). IL-1beta was not found in measurable quantities in any of the fibroblast cultures. Levels of IL-6 extracted from overgrown gingival tissue were significantly higher than in inflamed or normal tissue. In contrast IL-1beta levels in overgrown tissue were not statistically significantly greater than those in inflamed tissue. These results show that CsA does regulate cytokine expression in gingival tissue. This effect may play an important role in the pathogenesis of CsA-induced gingival overgrowth.

ニフェジピン歯肉増殖症におけるランゲルハンス細胞の上皮内分布および密度に関する免疫組織化学的研究

ニフェジピン歯肉増殖症におけるランゲルハンス細胞の上皮内分布および密度に関する免疫組織化学的研究

Comparative effects of cyclosporin on glycosaminoglycan synthesis by gingival fibroblasts.

Histological studies show that drug-induced gingival overgrowth results from an accumulation of the connective tissue component. Despite comprising a major part of gingival connective tissue, a role for glycosaminoglycans (GAGs) in the pathogenesis of gingival overgrowth has received scant attention. By analyzing the metabolism of 3H-glucosamine, we have compared GAG and hyaluronan synthesis by fibroblasts derived from normal and overgrown gingival tissue, and the effects of cyclosporin on GAG output. GAG production was cell density-dependent, fibroblasts cultured at low density synthesizing significantly increased quantities in comparison to confluent cultures. The effects of cyclosporin on GAG synthesis was also found to be both cell density- and cell strain-dependent. However, cyclosporin-stimulated GAG synthesis by 2/3 overgrown cell strains and 1/3 normal strains. These results suggest that a direct promotion of GAG synthesis by gingival fibroblasts in response to cyclosporin may play a role in the pathogenesis of gingival overgrowth.

Phenotypic differences in growth, matrix synthesis and response to nifedipine between fibroblasts derived from clinically healthy and overgrown gingival tissue.

Gingival overgrowth is a disfiguring condition affecting 10-20% of patients on nifedipine therapy. The pathogenesis of this condition, although unclear, is thought to involve an interaction between the drug and resident gingival fibroblasts. The aim of the present study was to investigate the cellular mechanisms underlying this condition using cell culture techniques. Gingival fibroblast cell lines were derived by explant culture from two patients on long-term nifedipine therapy exhibiting gingival overgrowth ('responders') and from two patients on similar therapy with clinically healthy gingiva ('non responders'). Comparative studies showed phenotypic differences between the two cell types, 'responder' cells having an increased growth potential and producing increased levels of protein and collagen compared to 'non responder' lines. Addition of exogenous nifedipine (10-1000 ng/ml) to cultures had no effect on 'non-responder' cells but induced a significant inhibitory response in the 'responder' cells. Although adding support to the concept that nifedipine-sensitive fibroblasts reside within overgrown connective tissue, the inhibitory effect of the drug on cell growth and matrix synthesis was surprising in view of the clinical appearance of this condition.

Cyclosporine A upregulates interleukin-6 gene expression in human gingiva: possible mechanism for gingival overgrowth.

Cyclosporine A (CsA) is a widely used immunosuppressant for transplant patients and is also used for the treatment of a wide variety of systemic diseases with immunologic components. A prominent side effect of CsA administration is gingival overgrowth. It has been postulated that CsA alters fibroblast activity through effects on various cytokines such as the interleukins, however, as yet, data concerning the molecular mechanisms involved in connective tissue proliferation are still preliminary in nature. The purpose of this study was to evaluate interleukin-6 (IL-6) gene expression in gingival tissues of patients receiving CsA therapy and exhibiting gingival overgrowth. Radioimmunoassay (RIA) demonstrated a significant difference in tissue levels of IL-6 as mean +/- SEM. IL-6 content in CsA-stimulated tissue was 184.3 +/- 30.2 ng/mg total protein versus 23.3 +/- 6.5 ng/mg total protein in control tissue. In situ hybridization indicated that overgrown gingival tissues from patients taking CsA had a significantly higher content of IL-6 mRNA when compared to control tissues. Expressing IL-6 mRNA levels as silver grains/cell, CsA-stimulated tissue had 166.9 +/- 12.0 grains of IL-6 mRNA/cell while control tissue had 12.8 +/- 3.0 grains of IL-6 mRNA/cell. These results demonstrate that CsA therapy results in increased levels of IL-6 protein and IL-6 mRNA in overgrown human gingival tissues. This is the first report of CsA-upregulated IL-6 gene expression in vivo, and may explain in part the molecular mechanisms responsible for CsA-induced gingival overgrowth.