Targeting SRD5A1 and MMP-2/NLRP3/TGF-ß1 axis alleviates the amlodipine-induced gingival hyperplasia in rats: Emerging role of saw palmetto and folic acid.

Saw palmetto (SAW), the herbal drug used to treat prostatic hyperplasia, exerts its antiproliferative effects by blocking steroid 5 alpha-reductase (SRD5A1) activity, that has also been involved in gingival hyperplasia (GH) pathogenesis. Concurrently, folic acid (FA) could reduce GH prevalence via its antioxidant and anti-inflammatory effects. Thus, this study tended to assess the potential therapeutic efficacy of SAW, alone and along with FA, against amlodipine-induced gingival inflammation and overgrowth in rats. Rats were grouped into (CONT, AIGH, SAW, SAW-treated, FA-treated, and SAW + FA-treated). SAW and FA were administered once daily for 4 weeks. Gingival SRD5A1, CTGF, GSK-3ß, and NLRP3 expressions, as well as T, DHT, MDA, TAC, ET-1, and MMP2 levels were determined. In addition, histopathological and immunohistochemical analyses of TNF-α, IL-6, TGF-ß1, and α-SMA were documented. Results declared that SAW and FA administration markedly ameliorated amlodipine-associated GH and may be presenting a novel therapeutic avenue in the future.

Phenytoin sodium-ameliorated gingival fibroblast aging is associated with autophagy.

BACKGROUND AND OBJECTIVE: Human gingival fibrolasts aging is an important cause of periodontal disease. Phenytoin sodium (phenytoin) has a side effect of gingival hyperplasia and an effect on the autophagy progress. This study investigated whether the effect of phenytoin on aging gingival fibroblast is related to the autophagy pathway. MATERIAL AND METHODS: The aging model of gingival fibroblast cell line HGF-1 was induced by hydrogen peroxide (H2 O2 ), and the treatment of phenytoin and 3-methyladenine (3-MA) was performed simultaneously. Cell viability, cell cycle, and intracellular calcium ion were measured by flow cytometry. Changes in expression of basic fibroblast growth factor (bFGF), P16INK4A , P21cip1 , and bFGF, P16INK4A , P21cip1 , LC3II, p62, and Beclin were tested by using reverse transcription polymerase chain reaction, western blot, and immunofluorescence staining. RESULTS: The results showed that aging HGF-1 proliferation was inhibited by H2 O2 , gene, protein expression of bFGF, P16INK4A , and P21cip1 were decreased, autophagy-related proteins LC3II, p62, and Becline were decreased, and the proportion of G0/G1 phase and intracellular calcium ion of cell cycle was increased. Phenytoin treatment could recovery above changes, but the effect of phenytoin could be blocked by 3-MA. CONCLUSION: We propose that phenytoin alleviates the aging of gingival fibroblasts induced by H2 O2 . This condition is related to the enhancement of autophagy pathway.

Role of Cyclosporine in Gingival Hyperplasia: An In Vitro Study on Gingival Fibroblasts.

BACKGROUND: Gingival hyperplasia could occur after the administration of cyclosporine A. Up to 90% of the patients submitted to immunosuppressant drugs have been reported to suffer from this side effect. The role of fibroblasts in gingival hyperplasia has been widely discussed by literature, showing contrasting results. In order to demonstrate the effect of cyclosporine A on the extracellular matrix component of fibroblasts, we investigated the gene expression profile of human fibroblasts after cyclosporine A administration. MATERIALS AND METHODS: Primary gingival fibroblasts were stimulated with 1000 ng/mL cyclosporine A solution for 16 h. Gene expression levels of 57 genes belonging to the "Extracellular Matrix and Adhesion Molecules" pathway were analyzed using real-time PCR in treated cells, compared to untreated cells used as control. RESULTS: Expression levels of different genes were significantly de-regulated. The gene CDH1, which codes for the cell adhesion protein E-cadherin, showed up-regulation. Almost all the extracellular matrix metalloproteases showed down-regulation (MMP8, MMP11, MMP15, MMP16, MMP24, MMP26). The administration of cyclosporine A was followed by down-regulation of other genes: COL7A1, the transmembrane receptors ITGB2 and ITGB4, and the basement membrane constituents LAMA2 and LAMB1. CONCLUSION: Data collected demonstrate that cyclosporine inhibits the secretion of matrix proteases, contributing to the accumulation of extracellular matrix components in the gingival connective tissue, causing gingival overgrowth. Patients affected by gingival overgrowth caused by cyclosporine A need to be further investigated in order to determine the role of this drug on fibroblasts.

Localized juvenile spongiotic gingival hyperplasia: A report of 27 cases.

BACKGROUND: Localized juvenile spongiotic gingival hyperplasia (LJSGH) is a poorly understood but distinctive inflammatory hyperplasia occurring in children and young adults. Fewer than 100 cases have been reported since its initial description. METHODS: During the period of 2015 to 2018, cases of LJSGH were identified, retrieved and their clinical and histopathological data reviewed. RESULTS: There were 27 cases, with a median age of 13 years (range 7-72 years). Twenty-four of 27 patients were less than 20 years old, and in three cases the patients were over 60 years of age. The most commonly affected site was the anterior maxillary gingiva presenting as a solitary, red, and papillated lesion. Typical microscopic findings included elevated areas of variably acanthotic, spongiotic nonkeratinized epithelium with elongated rete ridges, accompanied by a neutrophilic-rich infiltrate. An abrupt transition between epithelium affected by LJSGH and normal mucosa was characteristic. LJSGH typically exhibited full-thickness epithelial expression of CK19 without expression of estrogen and progesterone receptors. CONCLUSIONS: The clinical and histopathologic characteristics of LJSGH are unique and consistent. Despite the name, the condition is not limited to juveniles and can occur in adults. LJSGH in adults and juveniles shares the same spectrum of histopathologic and immunohistochemical findings.

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

BACKGROUND: 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. AIMS AND OBJECTIVES: (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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: The results indicate that the pathogenesis of amlodipine-induced gingival overgrowth might involve inhibition of apoptosis, especially with morphogenesis of hyperplastic gingival epithelia.

ABCB1 polymorphisms are associated with cyclosporine-induced nephrotoxicity and gingival hyperplasia in renal transplant recipients.

PURPOSE: There is a great deal of controversy regarding the clinical impact of genetic variants in patients receiving cyclosporine (CsA) as immunosuppressant therapy. We have investigated the effect of polymorphisms in the CYP3A and ABCB1 genes on CsA pharmacokinetics, acute rejection incidence and drug-related side effects in renal transplant recipients METHODS: The presence of CYP3A5*3, CYP3A4*1B and ABCB1 C1236T, G2677T/A and C3435T polymorphisms was assessed in 68 patients and retrospectively associated with pharmacokinetic and clinical parameters at 1 week and 1, 5 and 12 months after transplantation. RESULTS: Only minor associations were found between the tested polymorphisms and CsA pharmacokinetics. Most notably, CYP3A5 expressers showed lower blood trough levels than non-expressers in the first week after grafting (32.5 ± 14.7 vs. 55.1 ± 3.8 ng/ml per mg/day per kilogram). In terms of CsA-induced adverse effects, the incidence of nephrotoxicity was higher in carriers of the ABCB1 3435TT genotype and in those patients carrying four to six variants in the three ABCB1 loci [odds ratio (OR) 4.2, 95 % confidence interval (CI) 1.3-13.9, p = 0.02 and OR 3.6, 95 % CI 1.1-11.8, p = 0.05, respectively]. These subjects with four to six ABCB1 variants were also at higher risk for gingival hyperplasia (OR 3.29, 95 % CI 1.1-10.3, p = 0.04). Renal function and the incidence of neurotoxicity and of acute rejection did not vary across the different genotypes. CONCLUSIONS: ABCB1 polymorphisms may be helpful in predicting certain CsA-related side effects in renal transplant recipients. Our results also suggest that the mechanisms underlying these genetic associations are most likely independent of the drug's trough blood concentrations.

Association of transforming growth factor ß1 (TGF- ß1) with gingival hyperplasia in heart transplant patients undergoing cyclosporine-A treatment.

BACKGROUND: Gingival hyperplasia is a common complication of immunosuppressive therapy with cyclosporine A (CyA). However, the association of CyA with increased tissue concentrations of TGF- ß(1), a potential causative factor of hyperplasia, remains unknown. The aim of the study was to assess the impact of TGF- ß(1) and IL-2 on the development and maintenance of gingival hyperplasia in patients treated with CyA after orthotopic heart transplantation (OHT). MATERIAL/METHODS: Gingival hyperplasia was indexed in 60 patients, in accordance with McGraw and Potter scale. Patients were divided and comparisons were made among 3 groups: Group A (18 patients; 49.0 ± 12.1 y/o) after OHT with gingival hyperplasia (score 1, 2, 3), Group B (12 patients; 40.0 ± 15.1 y/o) after OHT without gingival hyperplasia (score 0), and Group C - the control group - (30 patients; 42.0 ± 10.8 y/o) with clinically healthy paradentium. Cytokines (TGF- ß(1) and IL-2) were marked in gingival tissue homogenate. The concentration of CyA was marked in the patients' blood (Groups A and B). RESULTS: The highest mean concentration of TGF- ß(1) was obtained in Group A and the lowest concentration was in the control group. A positive correlation was found between TGF- ß(1) in gingival tissue and CyA blood concentration in Groups A and B. CONCLUSIONS: TGF- ß(1) is associated with gingival hyperplasia in patients treated with CyA after OHT procedure.

Cathepsin B, D, and L regulation in cyclosporin A-mediated gingival hyperplasia of a patient with sarcoidosis.

BACKGROUND: Cyclosporin A (CsA) is an immunosuppressant with side effects including gingival hyperplasia. Sarcoidosis is a systemic disease characterized by granulomas. Here, we report on a rare case of sarcoidosis with gingival hyperplasia to clarify whether clinical observation corresponds to in vitro results. METHODS: Gingival fibroblasts (HGFs) were isolated from healthy gingiva and cultured with CsA. Total RNA was collected and expression of mRNAs examined using semi-quantitative RT-PCR analysis. Cathepsin B, D, and L expression in overgrown gingiva of the patient was examined by immunohistochemistry. RESULTS: Cathepsin D, L, and vascular endothelial growth factor (VEGF)165 mRNA were markedly suppressed in CsA-treated HGFs, whereas cathepsin B, matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of metalloproteinase-1 (TIMP-1) mRNA were not reduced. Next, the decrease of cathepsin B and L expression in enlarged gingiva was observed, whereas an increase of cathepsin D expression was observed. Clinically, the enlarged gingival lesions were fully resolved by performing oral infection control. CONCLUSIONS: Cathepsins regulation might be an important factor in the development of CsA-mediated gingival hyperplasia.

C-reactive protein in gingival crevicular fluid may be indicative of systemic inflammation.

BACKGROUND AND AIM: Periodontitis is associated with elevated C-reactive protein (CRP) in both serum and gingival crevicular fluid (GCF). Although the liver is the primary source of CRP, extra-hepatic production of CRP has been reported. This study aimed to determine whether CRP in GCF is produced locally in the gingivae. MATERIALS AND METHODS: Gingivae and GCF were collected from non-periodontitis and periodontitis sites. Presence of CRP in gingivae was assessed by immunohistochemistry. CRP in GCF was measured using ELISA. Gene expression for CRP in gingivae was determined using real-time polymerase chain reaction. RESULTS: CRP was found in both the gingivae and GCF. No gingivae had detectable amounts of CRP mRNA. Not all patients with periodontitis had detectable levels of CRP in the GCF. Some non-periodontitis patients had detectable levels of CRP in the GCF. CONCLUSION: CRP in the GCF appears to be of systemic origin, and therefore may be indicative of systemic inflammation from either a periodontal infection or inflammatory disease elsewhere. The correlation between levels of CRP in GCF and serum requires validation in future studies.

Heterogeneity and atypical presentation in infantile systemic hyalinosis with severe labio-gingival enlargement: first Egyptian report.

Infantile systemic hyalinosis (ISH) (MIM 236490) is a rare, progressive, fatal autosomal recessive condition characterized by widespread deposition of hyaline material in many tissues. Our proband was a 4-year-old male with growth retardation, severe labio-gingival enlargement, generalized stiff skin, joint contractures, and intractable diarrhea. We discovered a history of a brother and sister who suffered a more severe disease course. A final diagnosis of systemic hyalinosis was made; we report this case and discuss the clinical and orodental heterogeneity among these siblings in the first report of an Egyptian family with ISH. We present a very rare entity, infantile systemic hyalinosis, a cause of joint contracture, protein-losing enteropathy, and growth retardation in infancy with a review of the relevant literature.

Detection of gingival crevicular fluid cytokines in children and adolescents with and without fixed orthodontic appliances.

OBJECTIVE: To study the expression of IL-1beta, IL-4, and IL-8 in the gingival crevicular fluid (GCF) of children, adolescents, and young adults with and without fixed orthodontic appliances. MATERIAL AND METHODS: Eighty systemically healthy children and adolescents participated in the study: 56 aged between 8 and 16 years without any orthodontic appliance (Group A) and 24 aged between 10 and 20 years having worn fixed orthodontic appliances for at least 12 months (Group B). Clinical examination included presence or absence of plaque, probing depth, bleeding on probing, and gingival overgrowth. GCF was collected by means of Durapore strips from four randomly selected sites per subject. The contents of interleukin-1 beta (IL-1beta), interleukin-4 (IL-4), and interleukin-8 (IL-8) were detected by ELISA, measured as total amounts (pg/30s) and expressed in log scale. RESULTS: Statistically significant differences were noted for the mean log IL-1beta, IL-4, and IL-8 between the two groups: Group B showed significantly higher mean levels in log IL-1beta and log IL-8 compared to Group A. Mean levels of log IL-4 were lower in Group B, although they did not reach statistical significance. Furthermore, mean levels of log IL-1beta and log IL-8 were associated with bleeding sites (p<0.001) and gingival overgrowth, while mean level of log IL-4 was associated with non-bleeding sites and no gingival overgrowth (p<0.001). CONCLUSION: Our findings suggest that fixed orthodontic appliances result in an increase in the expression of IL-1beta and IL-8. This may reflect biologic activity in the periodontium during orthodontic tooth movement.

Association of galactose single-point test levels and phenytoin metabolic polymorphisms with gingival hyperplasia in patients receiving long-term phenytoin therapy.

STUDY OBJECTIVE: To evaluate whether the occurrence or severity of gingival hyperplasia is associated with liver function test results or phenytoin metabolism. DESIGN: Prospective analysis. SETTING: University-affiliated medical center in Taipei, Taiwan. PATIENTS: Sixty-six patients (mean age 37.9 yrs) with epilepsy who were receiving phenytoin for more than 1 year. Intervention. Four blood samples were drawn from each patient for liver function testing, concentrations of phenytoin and its metabolites R-5-(4'-hydroxyphenyl)-5-phenylhydantoin (R-HPPH) and S-HPPH, and genotyping of cytochrome P450 (CYP) 2C9 and 2C19. MEASUREMENTS AND MAIN RESULTS: Plasma concentrations of phenytoin and its metabolites were determined by a high-performance liquid chromatography method. The CYP2C9 and CYP2C19 genotypes were analyzed by polymerase chain reaction-restriction fragment length polymorphism analysis. Conventional liver function assays and a quantitative liver function test--galactose single-point (GSP) measurement--were performed. Statistical analyses were performed to evaluate the association between liver function test results as well as metabolic phenotype and the occurrence and severity of gingival hyperplasia. Among liver function tests, only GSP levels showed a significant difference between patients with and those without gingival hyperplasia. Patients with an elevated GSP level (> or = 280 microg/ml) had a significantly higher odds ratio (OR 4.51) for the occurrence of gingival hyperplasia. In addition, increased R-HPPH (OR 1.02) and phenytoin (OR 1.09) concentrations were associated with an increased occurrence of gingival hyperplasia. However, only increased GSP and R-HPPH concentrations had significantly higher ORs (2.84 and 1.02, respectively) associated with the severity of gingival hyperplasia. Although mean +/- SD plasma R-HPPH concentration was significantly lower in CYP2C19 poor metabolizers compared with CYP2C9 and CYP2C19 extensive metabolizers and CYP2C9 poor metabolizers (30.38 +/- 16.73 vs 68.22 +/- 44.75 and 78.95 +/- 51.67 microg/ml, respectively), no significant association between genotype and gingival hyperplasia was found. CONCLUSION: Increased GSP, phenytoin, and R-HPPH concentrations were associated with increased occurrence of phenytoin-induced gingival hyperplasia; only increased GSP and R-HPPH concentrations were associated with increased severity of this adverse effect.

[Connective tissue growth factors, CTGF and Cyr61 in drug-induced gingival overgrowth--an animal model]. / Factorii de crestere ai tesutului conjunctiv, CTGF si Cyr61, in hipercresterea gingivala indusa medicamentos. Model experimental animal.

Human gingival overgrowth may occur as a side effect of chronic administration of some therapeutic agents. The mechanisms responsible for the gingival tissues lesions, fibrosis and inflamation, involve an impaired balance between the production and the degradation of type I collagen. It has been demonstrated that CCN2/CTGF, a connective tissue growth factor, is highly expressed in the gingival tissues and positively correlated with the degree of fibrosis in the drug-induced gingival overgrowth. The aim of this study was to identify the presence and localization of CCN2/CTGF and CCN1/Cyr61, members of the same molecular family, in gingival tissues of cyclosporin A- and nifedipine-treated rats, by immunohistochemistry. Staining was evaluated with light microscope and the results show cellular and extracellular CTGF in nifedipin gingival overgrowth tissues with intensity of labeling higher compared to the CsA gingival overgrowth tissues or the controls. The staining for Cyr61 shows its intracellular localization with no diference of labeling intensity between drug-induced gingival overgrowth and normal tissues. Also, we were interested in the gingival TGF-â expression in those animals. We didn't find any commercial anti-rat TGF antibody and our anti-human antibody shows no cross-reactivity with rat tissues. The data from our study sustain the involvement of CTGF and Cyr61 as growth factors in the gingival tissues and the CTGF association with drug-induced gingival overgrowth.

An immunohistochemical evaluation of BMP-2, -4, osteopontin, osteocalcin and PCNA between ossifying fibromas of the jaws and peripheral cemento-ossifying fibromas on the gingiva.

The present study examined histological difference between ossifying fibromas (OF, n=5) and peripheral cemento-ossifying fibromas (PCOF, n=7). Bone morphogenetic proteins (BMP)-2 and -4, osteopontin (OPN), osteocalcin (OCN) and proliferating cell nuclear antigen (PCNA) were used for the immunohistochemical examinations. Oxytalan fibers present at the periodontal tissue were stained to determine the tumor cell origin. Many OFs showed high immunohistochemical reactions for BMP-2, -4 and OPN compared to those of PCOFs. PCNA index (IP) of OFs was significantly higher than that of PCOFs. All the PCOFs showed a high expression of oxytalan fibers. Only two OFs exhibited a small number of oxytalan fibers. These results suggest that PCOF has only little ability to form hard tissue and seems to be a reactive lesion. The expression of oxytalan fibers reveals that OF does not only originate from periodontal tissue.

Cyclosporin-induced downregulation of the expression of E-cadherin during proliferation of edentulous gingival epithelium in rats.

BACKGROUND: To examine the role of E-cadherin in epithelial hyperplasia of cyclosporin A (CsA)-induced gingival enlargement, mRNA and protein levels of E-cadherin, beta-catenin, proliferating cell nuclear antigen (PCNA), and Cyclin D1 were examined in the edentulous gingiva of rats following CsA treatment. METHODS: Three weeks after the extraction of all maxillary molars, 20 male Sprague-Dawley rats were assigned to a CsA-fed group (30 mg/kg daily) or a control group. Five rats per group were sacrificed at weeks 1 and 4. Edentulous ridge specimens were taken, and the expression levels of E-cadherin, beta-catenin, Cyclin D1, and PCNA mRNAs were estimated by reverse transcription-polymerase chain reaction (RT-PCR). Tissue specimens of the week 4 groups were examined using immunohistochemical (IHC) staining for proteins. RESULTS: The mRNA expression of E-cadherin was significantly weaker in the CsA-treated group than the control group at both times. Using IHC staining, a weaker level of membrane-bonded E-cadherin was also observed in the gingival epithelial cells in the CsA group than in controls. By contrast, significantly stronger beta-catenin and Cyclin D1 mRNA expressions and protein levels were found in CsA-treated rats than controls by RT-PCR and immunohistochemistry at week 4, whereas PCNA production was stronger at both times. CONCLUSIONS: CsA treatment reduced the production of E-cadherin but increased the production of beta-catenin, Cyclin D1, and PCNA. Thus, CsA may downregulate E-cadherin gene expression, leading to the epithelial cell proliferation of gingival overgrowth.

Effect of cyclosporin A on apoptosis and expression of p53 and bcl-2 proteins in the gingiva of renal transplant patients.

BACKGROUND: Gingival overgrowth (GO) is a common side effect of cyclosporin A (CsA) therapy, but the exact mechanism for this is unknown. Apoptosis plays an important role in the maintenance of tissue homeostasis and mediators of this process may be involved in the pathogenesis of drug-induced GO. This study compared p53 expression, bcl-2 expression, and apoptosis in gingival samples from CsA-treated renal transplant recipients to findings in controls with gingivitis. METHODS: Twenty-two kidney recipients with CsA-induced GO and 15 systemically healthy subjects with gingivitis were included in the study. The 15 systemically and periodontally healthy volunteer control group were immunohistochemically analyzed for grades of p53 and bcl-2 expression, and were processed using terminal TdT-mediated dUTP-biotin nick-end labeling (TUNEL) technique to identify and grade levels of apoptosis. RESULTS: There were no differences between the CsA group and the control group with respect to grades of p53 and bcl-2 expression (P >0.05 for both). However, the CsA group showed a lower apoptosis grade than the control group (P <0.05). None of the clinical parameters was significantly correlated with any of the immunohistochemical findings for p53 or bcl-2 (P >0.05 for all). Similarly, grade of apoptosis was not correlated with any of the clinical parameters (P >0.05). There was a significant positive correlation between serum CsA level and level of bcl-2 expression, but serum CsA was not significantly correlated with level of apoptosis or level of p53 expression. CONCLUSION: The results indicate that the pathogenesis of CsA-induced GO might involve inhibition of apoptosis, and overexpression of bcl-2 in the setting of high serum CsA.

On the relation of nitric oxide to nifedipine-induced gingival hyperplasia and impaired submandibular glands function in rats in vivo.

Calcium-channel blockers such as nifedipine could be associated with gingival overgrowth. The aim of this study was to examine the role of nitric oxide (NO) on nifedipine-induced gingival hyperplasia along with submandibular secretory function in rats. Animals in divided groups received nifedipine (250 mg/kg diet) alone and in combination with L-arginine (2.25% w/v) or N(omega)-nitro-L-arginine methyl ester (L-NAME) (0.7% w/v) in drinking water for 20 days. Controls received only tap water. Pure submandibular saliva was collected intraorally by micropolyethylene cannula and the mandibular gingiva was examined by means of dissecting microscope for signs of redness, thickness, inflammation and exuda. Twenty-day nifedipine treatment induced gingival hyperplasia accompanied with reduced salivary flow rate and concentrations of total protein, epidermal growth factor (EGF) and calcium in comparison with controls. Co-treatment of animals with nifedipine and L-arginine protected from gingival hyperplasia and retained flow rate, and concentrations of total protein, EGF and calcium in normal levels. Co-treatment of animals with nifedipine and L-NAME potentiated nifedipine-induced gingival hyperplasia and reductions in flow rate and concentrations of total protein, EGF, and calcium. It is concluded that nifedipine-induced gingival hyperplasia is associated with salivary dysfunction. Activation of cGMP-dependent positive signal-transduction mechanisms in salivary glands might be the mechanism for protective effects of NO against nifedipine-induced gingival hyperplasia.

Expression of growth factors in the gingival crevice fluid of patients with phenytoin-induced gingival enlargement.

The mechanism underlying phenytoin (PHT)-induced gingival enlargement (GE) is not yet known. The aim of the present study was to investigate transforming growth factor-beta1 (TGF-beta1), platelet-derived growth factor-BB (PDGF-BB) and basic fibroblast growth factor (bFGF) profiles in the gingival crevice fluid (GCF) of patients with PHT-induced GE and to compare the results with healthy controls. Five PHT-treated patients and five healthy subjects with normal periodontal tissue were included in this study. GCF samples were collected from (i) enlarged gingival sites in patients receiving PHT (GE+); (ii) non-enlarged gingival sites in the same patients (GE-); (iii) normal gingival sites of healthy subjects (control). The levels of TGF-beta1, PDGF-BB and bFGF in the GCF samples were analysed by ELISA. The results showed that the total amounts of TGF-beta1 and PDGF-BB in the GE+ group were higher than in the GE- group and significantly higher than in the control group (P < 0.05). However, no significant differences were found between the groups when the concentrations of these growth factors were compared. bFGF levels were not compared as this growth factor could be detected in only 33, 41 and 44% of the GE+, GE- and control GCF samples, respectively. These results show that TGF-beta1 and PDGF-BB are readily detectable in GCF obtained from enlarged and non-enlarged sites of PHT recipients and suggest that since the amounts were markedly higher at the GE+ than the GE- sites, the systemic administration of PHT has a pronounced localised effect on the levels of these growth factors. Moreover, our findings provide evidence that both TGF-beta1 and PDGF-BB are closely associated with the clinical manifestation of PHT-induced GE.

Effect of nifedipine on the expression of bcl-2 protein in rat gingiva.

Bcl-2 is a family of proteins involved in protecting the cell against death stimuli or in promoting cell death. The aim of the present study was to determine the effect of nifedipine treatment on the expression of bcl-2 protein in rat gingival tissues. Rats were given gastric intubation with various concentrations and durations of nifedipine. Nifedipine-untreated and dimethylsulfoxide (DMSO)-treated animals served as control groups. The gingival tissues were dissected and the expression of bcl-2 protein was determined immunohistochemically. The results showed that the numbers of bcl-2-positive cells in the gingiva of nifedipine-treated animals were significantly higher than in the control groups. These numbers increased parallel to increased concentration and duration of nifedipine treatment. The results suggest that nifedipine treatment may induce the expression of bcl-2 protein in rat gingival tissue in a dose- and duration-dependent fashion and that this proto-oncogenic protein may play a role in nifedipine-induced gingival hyperplasia.

Keratinocyte growth factor receptor is up-regulated in cyclosporin A-induced gingival hyperplasia.

Keratinocyte growth factor stimulates the growth and activity of epithelial cells via the keratinocyte growth factor receptor. We have recently shown that the growth factor is markedly elevated in cyclosporin A-induced gingival hyperplasia tissue in vivo, but the effects of cyclosporin A on the receptor are not yet known. The present study was therefore carried out to determine whether expression of the keratinocyte growth factor receptor is up-regulated in gingival hyperplasia compared with normal gingiva. Using immunohistochemistry and the reverse-transcribed polymerase chain-reaction, we obtained results which showed that receptor antigen and gene transcript levels were both elevated in gingival hyperplasia tissue. In addition, flow cytometry and the reverse-transcribed polymerase chain-reaction showed that the receptor and mRNA were also higher in gingival epithelial cells following incubation with cyclosporin A in vitro. These findings suggest that the keratinocyte growth factor-receptor pathway of mesenchymal-epithelial interaction could play an important part in the molecular pathogenesis of gingival hyperplasia.