TGF-β isoforms and TGF-β receptors in drug-induced and hereditary gingival overgrowth

Drug therapy and hereditary factors are two of the main causes of gingival overgrowth (GO). Both of these forms of GO are associated with increased extracellular matrix production by fibroblasts. Transforming growth factor beta (TGF-beta) is an important mediator of wound healing and tissue regeneration, which stimulates fibroblasts to produce extracellular matrix materials. The aim of this immunohistochemical study was to determine whether there is any altered expression of TGF-beta isoforms or its receptors in tissue from patients with drug-induced GO (DIGO; n=10) and hereditary gingival fibromatosis (n=10) when compared to non-overgrowth tissue (n=10). Compared to control tissues, significantly more fibroblasts expressed TGF-beta1 in both DIGO and hereditary gingival fibromatosis tissues (P<0.03). Cells expressing TGF-beta2 were present at control levels in DIGO but were significantly reduced in hereditary gingival fibromatosis (P<0.02). By contrast, the number of TGF-beta3-positive cells was the same in overgrowth tissues and controls. However, because of differences in total fibroblast densities between groups, there was a proportional increase in TGF-beta3 as well as TGF-beta1 expressing cells within both overgrowth populations (P<0.0001). Furthermore, representation of the TGF-beta2-positive phenotype was reduced in hereditary gingival fibromatosis (P<0.01) but increased in DIGO (P<0.005) compared to controls. Absorbance measurements of the positive cell populations showed that the level of expression was significantly higher for TGF-beta1 in hereditary gingival fibromatosis (P<0.002) and significantly lower for TGF-beta3 in DIGO (P<0.03). No significant differences in the numbers of TGF-betaRI- or RII-positive cells were detected between overgrowth tissues and controls. However, there were increases in the proportion of receptor-positive cells in the total cell population analysed in overgrowth tissues (P<0.0001). These results indicate qualitative and quantitative differences in TGF-beta isoform and receptor expression by fibroblasts in gingival overgrowth that may contribute to disease pathogenesis.     

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目的评价吸烟与非吸烟药物性牙龈增生患者单纯牙周非手术治疗1个月后的临床疗效。方法2007年3月至2007年12月收集河北省人民医院口腔科钙拮抗剂类药物导致的牙龈增生男性患者20例,其中吸烟组9例,非吸烟组11例,两组患者基线时的临床参数具有可比性。观察的牙龈增生牙齿,探诊深度5~7mm,吸烟组78个位点,非吸烟组80个位点。在未停药的情况下进行牙周非手术治疗,观察这些位点在治疗前、后1个月菌斑指数(PLI)、探诊深度(PD)、附着丧失(AL)、牙龈增生指数(HI)和出血指数(BI)的变化。结果治疗前两组PLI、BI、PD、AL以及HI差异无统计学意义,牙周非手术治疗1个月后,两组临床指标均有明显改善,吸烟组改善程度明显低于非吸烟组,但只有PD、PLI和HI的变化有统计学意义(P<0.05),AL和BI变化无统计学意义(P>0.05)。结论药物性牙龈增生患者,牙周非手术治疗效果吸烟者差于非吸烟者。     

Histomorphometric characteristics and expression of epidermal growth factor and its receptor by epithelial cells of normal gingiva and hereditary gingival fibromatosis

OBJECTIVE: The objective of this study was to examine the histomorphometric features and evaluate the expression of epidermal growth factor (EGF) and transmembranic receptor (EGFr) and the proliferative potential of epithelial cells from normal and hereditary gingival fibromatosis (HGF) gingival tissues. BACKGROUND: EGF is a multifunctional cytokine with a variety of biological effects including stimulation of cell proliferation by binding to its specific EGFr. METHODS: Immunohistochemistry was performed to measure EGF and EGFr expression and the epithelial cell proliferation was determined by measuring proliferating cell nuclear antigen (PCNA). RESULTS: Histomorphometric evaluation indicated that in HGF the mean height of the epithelial papillae was higher compared to the normal gingiva (NG), whereas mean epithelial area and number of epithelial papillae were quite similar in both groups. The EGF and EGFr positive cells were observed in the basal, spinous and granular cell layers of both normal and HGF tissues, with a gradual reduction from the basal layer. Although the expressions of EGF and EGFr in the control group were significantly higher than those from HGF, in HGF the epithelial papilla tips showed increased number of proliferating cells and elevated expression of EGF and EGFr. There was a correlation between the proliferative potential of epithelial cells and the expression of EGF or EGFr only in the epithelial papilla tips of HGF gingiva. CONCLUSION: Our data suggest that EGF and EGFr in the oral epithelium of HGF gingiva may stimulate epithelial cell proliferation, with the resultant apical migration of the oral epithelium and formation of the slender deep epithelial papillae; however, without hyperplastic alterations.     

Regulation of epidermal growth factor receptor metabolism in gingival fibroblasts by phenytoin in vitro

Normal human gingival fibroblasts derived from five children between 8 and 12 yr of age were cultured under serum-free conditions in the presence of epidermal growth factor (EGF) either alone or in combination with 5,5-diphenylhydantoin (phenytoin; PHT). DNA-synthesis, binding of EGF to its cell-surface receptor and internalisation of EGF-receptor-ligand complexes were studied. In normal gingival fibroblasts treated solely with EGF for 48 h, DNA synthesis increased significantly, as in cells treated solely with PHT. When EGF binding data was calculated according to Scatchard, it was found that the number of EGF receptors in fibroblasts increased significantly after PHT treatment. The number of EGF-receptors in untreated gingival fibroblasts varied from 147,000 to 170,000 receptors per cell whereas in PHT-treated fibroblasts the range was from 181,000 to 280,000. The study indicates that PHT regulates EGF-receptor metabolism in human gingival fibroblasts by increasing the number of cell-surface EGF-receptors which may contribute to the alteration of gingival connective tissue observed in patients undergoing PHT medication.     

Disposition of nifedipine in plasma and gingival crevicular fluid in relation to drug-induced gingival overgrowth

The present study investigates the relationship between the pharmacokinetic variables of nifedipine with the incidence and severity of gingival overgrowth in 9 adult male patients medicated with the drug for at least 6 months. Five of the patients had experienced significant gingival changes and were thus designated "responders". The remaining four patients exhibited no gingival overgrowth, and thus acted as a control. A baseline periodontal examination (plaque scores, bleeding index and gingival overgrowth assessment) was carried out on each patient, and confined to the upper and lower anterior teeth. Serial blood and gingival crevicular fluid samples were collected over an eight-hour investigation period. Samples were analyzed for nifedipine by gas chromatography. No significant difference (p>0.05) was seen between responders and non-responders with regard to drug therapy, periodontal parameters or plasma pharmacokinetics of nifedipine. Nifedipine was detected in the gingival crevicular fluid of seven subjects (all responders, and two non-responders). The peak concentration of nifedipine in crevicular fluid was 15–90 fold greater than levels observed in plasma.     

Epidermal growth factor in saliva and serum of patients with cyclosporin-induced gingival overgrowth

The purpose of this study was to investigate the presence of epidermal growth factor (EGF) in patients receiving cyclosporin therapy who had gingival overgrowth and to determine whether there were any differences between these patients and normal healthy controls. Seventeen patients with cyclosporin-induced gingival overgrowth and seventeen age- and sex-matched controls who were taking cyclosporin but had healthy gingiva were used for this study. Unstimulated whole saliva was collected from all individuals by expectoration. Gingival crevicular fluid (GCF) was also collected from all individuals. Blood was additionally collected from all subjects and serum was separated by keeping the samples overnight at 4 degrees C. EGF levels in all cases were measured by an ELISA assay. EGF concentrations were found to be significantly higher in the saliva of patients with cyclosporin-induced gingival overgrowth compared to the control group (401.2 +/- 31.1 pg/ml and 144.3 +/- 31.4 pg/ml, respectively), whereas the results were reversed in the serum (67.0 +/- 15.6 pg/ml and 141.6 +/- 17.7 pg/ml, respectively). EGF was not detected in the samples of GCF in either group. This study thus demonstrated an increase in EGF levels in the saliva and a decrease of EGF in the serum of patients with cyclosporin-induced gingival overgrowth.     

Platelet-derived growth factor reduces the inhibitory effects of lipopolysaccharide on gingival fibroblast proliferation

Lipopolysaccharide from a variety of bacterial sources is known to inhibit gingival fibroblast proliferation and synthetic activity and has been implicated in the pathogenesis of periodontal inflammation. However, it may be involved not only in pathogenesis but also be responsible for delayed wound healing following periodontal therapy. The aim of this investigation was to determine whether the inhibitory effect of LPS on gingival fibroblast proliferation could be reversed by growth factors. Human gingival fibroblasts were cultured in the presence of varying concentrations of platelet-derived growth factor (PDGF) or Salmonella enteritidis LPS to determine the optimal concentrations for stimulation and inhibition of proliferation respectively. The effect of PDGF on LPS inhibition of fibroblast proliferation was studied by combining PDGF and LPS together at the outset of the experimental period or adding PDGF to cells which had been previously primed with LPS. Cell proliferation was monitored by incorporation of 3H-thymidine into precipitable DNA. The results indicated that maximal inhibition of fibroblast proliferation was obtained with 50 micrograms/ml LPS and maximal stimulation of proliferation with 5 ng/ml PDGF. PDGF was found to restore the proliferative activity of the cells exposed to LPS to approximately 60% of their control counterparts. A similar value was obtained for cultures exposed to PDGF after an extended priming period of LPS exposure. Subtle differences were noted in the time taken for cells to complete their cell cycle in the various culture conditions and this may reflect variations in subpopulations of cells in their response to various mitogenic stimuli. Overall the results indicate that PDGF has the capacity to significantly negate and reverse the inhibitory effects of LPS on human gingival fibroblast proliferation.     

Phenytoin metabolism to 5-(4-hydroxyphenyl)-5-phenylhydantoin (HPPH) in man, cat and rat in vitro and in vivo, and susceptibility to phenytoin-induced gingival overgrowth

Interspecies differences in phenytoin (PHT) metabolism to 5-(4-hydroxyphenyl)-5-phenylhydantoin (HPPH) were examined in human, cat and rat hepatic microsomes in vitro. Rat liver microsomes were 25 and 650 times more efficient at the conversion of PHT to HPPH than human and cat liver microsomes, respectively. Sulphaphenazole (83%) and tolbutamide (TOL) (64%) were the most potent inhibitors of HPPH formation in human liver microsomes, while ciprofloxacin (27%), enoxacin (27%) and TOL (26%) produced the greatest inhibition in cat liver microsomes. TOL was tested for its effect on HPPH formation and gingival overgrowth in cats in vivo. Eight cats received PHT sodium (4 mg/kg/d) and another 8 cats received PHT sodium together with TOL (20 mg/kg/d) for 10 wk. Six cats (75%) in the PHT group and 4 cats (50%) in the PHT & TOL group developed significant gingival overgrowth by the end of the study. However, the extent and incidence of the overgrowth were similar in the 2 groups. There were no significant differences in mean AUC 0-10 weeks for plasma PHT (552.90 +/- 29.6 micrograms.d/mL [PHT alone] vs. 582.41 +/- 24.49 micrograms.d/mL [PHT & TOL]) and unconjugated HPPH (1016.4 +/- 295.5 ng.d/mL [PHT alone] vs. 1174.5 +/- 397.2 ng.d/mL [PHT & TOL]) concentrations between the 2 groups of cats. Neither PHT nor HPPH were detectable in the plasma of 8 rats which received PHT (4 mg/kg/d) over a 10-wk period. The rats showed no sign of gingival inflammation (mean gingival index = 0) or gingival overgrowth (mean gingival overgrowth index = 0). Thirty-six adult epileptic patients on chronic PHT therapy were examined; 17 (47%) of the patients demonstrated clinically significant overgrowth. The mean steady-state plasma PHT concentration was comparable to, and the mean plasma unconjugated HPPH concentration 5-fold greater than, that observed in the cats. The results suggest that the rapid metabolism and elimination of PHT and HPPH in the rat may enable it to become more resistant towards developing gingival overgrowth, compared to the cat and man.     

Immunohistochemical analysis of Th1/Th2 cytokine profiles and androgen receptor expression in the pathogenesis of nifedipine-induced gingival overgrowth

BACKGROUND: Numerous studies have demonstrated that gingival overgrowth may be associated with androgen and cytokine expression in tissues. OBJECTIVES: The aim of this study was to compare the expression of androgen receptor-presenting cells (AR+ cells) and Th1/Th2 cytokine [Th1: interleukin (IL)-2, interferon-gamma (IFN-gamma); Th2: IL-4, IL-10, IL-13] expression cells in tissue sections of patients with gingival overgrowth. MATERIALS AND METHODS: Tissue samples were collected from patients with healthy periodontium (H group), adult periodontitis (P group), surgically extracted teeth (S group), and nifedipine-induced gingival overgrowth (NIGO group). The clinical periodontal parameters of pocket depth (PD), bleeding on probing (BOP), and plaque control record (PCR) were measured around selected sample teeth. Gingival biopsies were further processed by immunohistochemical staining method. The expressions of cells positive for AR, IL-2, IFN-gamma, IL-4, IL-10, and IL-13 were counted by predetermined semiquantitative methods. RESULTS: Our results indicated that AR, IL-2, IFN-gamma, IL-4, IL-10, and IL-13 were intensively expressed in the nuclei of inflammatory cells and fibroblasts of gingival connective tissue. Stronger expressions of AR, IL-2, and IFN-gamma were found in the NIGO group. The AR+ cells/0.01 mm2 in gingival fibroblasts were significantly higher in the NIGO group (80.2 +/- 10.7) than those of the periodontitis group (52.5 +/- 11.8) and control group (37.4 +/- 11.3) (P < 0.05). The cytokine expression of the NIGO group showed a trend towards Th1-type expression (IL-2; P = 0.0001). In the surgically extracted tooth group, a stronger expression of Th2-type cytokine (IL-4, Il-10, IL-13; P < 0.05) was found in inflammatory cells. In a comparison of the IL-2/IL-4-labeled cell ratio of the four groups, a descending sequence was discovered as NIGO group (0.92 +/- 0.97) > H group (0.81 +/- 0.61) > P group (0.77 +/- 0.82) > S group (0.58 +/- 1.77). CONCLUSIONS: Our data support the following: (i) taking nifedipine may elevate the expression of AR in susceptible oral tissue, e.g. gingiva; (ii) the cytokine profile of T-cells in NIGO tissue indicates a trend preferentially towards Th1 activity; and (iii) elevation of AR expression cells and prominent Th1 cytokine-labeled cells are two significant factors in the pathogenesis of NIGO.     

环孢素对大鼠牙龈上皮细胞凋亡及Bcl-2、Caspase-3蛋白表达的影响

目的 观察环孢素(CsP)对大鼠牙龈上皮细胞凋亡活动、凋亡相关蛋白Bcl-2和Caspase-3表达的影响,探讨CsP致牙龈上皮增厚的可能机制.方法 SPF级7周龄雄性Wistar大鼠80只,随机分为实验组和对照组,每组又分为10、20、30、40 d亚组,实验组胃饲含CsP鲜牛奶,对照组胃饲等量鲜牛奶.经心灌注4%多...     

Transforming growth factor-beta1 gene expression and cyclosporine A-induced gingival overgrowth: a pilot study

Aims: The relationship between gingival overgrowth (GO) induced by cyclosporine A (CsA) and transforming growth factor‐β1 (TGF‐β1) remains unclear. The aims of the present study were to evaluate TGF‐β1 gene expression under different immunosuppressive treatments and its association with TGF‐β1 gene functional polymorphism and GO in renal transplant recipients. Material and Methods: The study included 98 CsA‐treated renal transplant recipients (with and without GO) and 44 tacrolimus‐treated transplant patients (without GO). TGF‐β1 mRNA expression was measured using a real‐time quantitative polymerase chain reaction assay. The levels were correlated with TGF‐β1 gene polymorphisms at codons 10 and 25, with different immunosuppressive treatment and GO. Results: The level of TGF‐β1 gene expression was insignificantly lower in the CsA‐treated group compared with the tacrolimus group, and significantly lower in the group with GO compared with patients without GO. In tacrolimus‐ and CsA‐treated patients, but not in patients with GO, the level of TGF‐β1 gene expression was associated with functional phenotypes of TGF‐β1. The incidence, degree and extent of GO were higher in recipients with lower TGF‐β1 gene expression. Conclusions: Lower level TGF‐β1 gene expression, not functional polymorphism, in patients treated with CsA may be considered to be a risk factor for GO.     

人血小板源性生长因子-B基因转染犬牙龈成纤维细胞的瞬时表达检测

目的 检测携带人血小板源性生长因子-B(hPDGF-B)基因的真核表达质粒在Beagle犬牙龈成纤维细胞内的表达.方法 扩增和鉴定携带hPDGF-B基因的质粒EX-A0380-M03,脂质体介导的方法转染Bealge犬牙龈成纤维细胞,RT-PCR、免疫细胞化学、ELISA以及Western blot检测hPDGF-BB...