Pathogenesis Of Gingival Overgrowth Research Articles

Phenytoin induces connective tissue growth factor (CTGF/CCN2) production through NADPH oxidase 4-mediated latent TGFβ1 activation in human gingiva fibroblasts: Suppression by curcumin.

Gingival overgrowth (GO) is a common side effect of some drugs such as anticonvulsants, immunosuppressant, and calcium channel blockers. Among them, the antiepileptic agent phenytoin is the most common agent related to this condition due to its high incidence. Transforming growth factor β (TGFβ) importantly contributes to the pathogenesis of GO. Connective tissue growth factor (CTGF or CCN2) is a key mediator of tissue fibrosis and is positively associated with the degree of fibrosis in GO. We previously showed that Src, c-jun N-terminal kinase, and Smad3 mediate TGFβ1-induced CCN2 protein expression in human gingival fibroblasts (HGFs). This study investigates whether phenytoin can induce CCN2 synthesis through activated latent TGFβ in HGFs and its mechanisms. CCN2 synthesis, latent TGFβ1 activation, and cellular reactive oxygen species (ROS) generation in HGFs were studied using western blot analysis, a TGFβ1 Emax® ImmunoAssay System, and 2',7'-dichlorodihydrofluorescein diacetate (an oxidation-sensitive fluorescent probe), respectively. Phenytoin significantly stimulated CCN2 synthesis, latent TGFβ1 activation, and ROS generation in HGFs. Addition of an TGFβ-neutralizing antibody, TGFβ receptor kinase inhibitor SB431542, and Smad3 inhibitor SIS3 completely inhibited phenytoin-induced CCN2 synthesis. General antioxidant N-acetylcysteine, NADPH oxidase (NOX) inhibitor diphenylene iodonium, and specific NOX4 inhibitor plumbagin almost completely suppressed phenytoin-induced total cellular ROS and latent TGFβ1 activation. Curcumin dose-dependently decreased phenytoin-induced TGFβ1 activation and CCN2 synthesis in HGFs. Our findings indicated that NOX4-derived ROS play pivotal roles in phenytoin-induced latent TGFβ1 activation. Molecular targeting the phenytoin/NOX4/ROS/TGFβ1 pathway may provide promising strategies for the prevention and treatment of GO. Curcumin-inhibited phenytoin-induced CCN2 synthesis is caused by the suppression of latent TGFβ1 activation.

The gingival crevicular fluid levels of growth factors in patients with amlodipine-induced gingival overgrowth: A pilot study.

Amlodipine, calcium channel blocker (CCB), is used in the management of cardiovascular diseases which causes gingival overgrowth (GO). The growth factors may have a role in the pathogenesis of amlodipine-induced GO. This pilot study aimed to investigate the growth factors including transforming growth factor-b1 (TGF-b1), platelet-derived growth factor-BB (PDGF-BB), and basic fibroblast growth factor (bFGF) in gingival crevicular fluid (GCF) of patients with amlodipine-induced GO and compare with of healthy subjects. GCF samples were collected from 56 sites presenting GO (GO + group) and from 38 sites not presenting GO (GO- group) of 5 patients using amlodipine for more than one year, and from 45 sites (control group) of 5 healthy subjects. The levels of TGF-b1, PDGF-BB, and bFGF were determined by using ELISA kits. The mean concentration of TGF-b1 in GCF samples of GO + group (9.50 ± 7.30 ng/ml) was higher than both GO- group (2.07 ± 0.50 ng/ml) and control group (2.74 ± 1.01 ng/ml) (P = 0.014). No significant difference was found among the groups in the GCF levels of PDGF-BB (P = 0.767). bFGF was detected in only 33% of the sites from patients. These preliminary results suggest that TGF-b1 may play a crucial role in the pathogenesis of amlodipine-induced GO.

Gingival Overgrowth as a complication of kidney transplantation – Nepali perspective

Gingival Overgrowth is a known and common complication with multifactorial etiology seen in kidney transplant recipients. Gingival Overgrowth is induced in kidney transplant recipients by Cyclosporin A and Calcium Channel Blockers that are frequently prescribed to them as immunosuppressive and antihypertensive, respectively. There have been 1477 kidney transplantations in Nepal since the first kidney transplantation in 2008, but cases of gingival Overgrowth have not been reported in any publications. The aim of this review is to discuss the different aspects of gingival Overgrowth and its relevance to kidney transplant recipients of Nepal. This review will emphasize the need to examine the oral cavity of kidney transplant recipients. Genetic predisposition, oral health, and offending drugs are involved in the pathogenesis of gingival Overgrowth. This review discusses the pathogenesis, clinical features, and management aspects of gingival Overgrowth in kidney transplantation recipients. The reason for gingival Overgrowth not being reported in Nepal could be due to various reasons like favorable genes, good oral hygiene, or avoidance of drugs that cause gingival Overgrowth in kidney transplantation recipients. This could also be due to gingival Overgrowth being ignored by the patients and the treating doctors. These aspects are reviewed with reference to previous publications.

Periodontal Microbiological Status Influences the Occurrence of Cyclosporine-A and Tacrolimus-Induced Gingival Overgrowth

Immune suppressed renal transplant patients are more prone to developing oral tissue alterations due to medications associated with a pleiotropic set of side effects involving the oral cavity. Drug-induced gingival overgrowth (DIGO) is the most commonly encountered side effect resulting from administration of calcineurin inhibitors such as cyclosporine-A (CsA), the standard first-line treatment for graft rejection prevention in transplant patients. Pathogenesis of gingival overgrowth (GO) is determined by the interrelation between medications and a pre-existing inflammatory periodontal condition, the main modifiable risk factor. Severity of gingival hyperplasia clinical manifestation is also related to calcium channel blocker association, frequently provided in addition to pharmacological therapy of transplant recipients. Specifically, nifedipine-induced enlargements have a higher prevalence rate compared to amlodipine-induced enlargements; 47.8% and 3.3% respectively. Available epidemiological data show a gender difference in prevalence, whereby males are generally more frequently affected than females. The impact of GO on the well-being of an individual is significant, often leading to complications related to masticatory function and phonation, a side effect that may necessitate switching to the tacrolimus drug that, under a similar regimen, is associated with a low incidence of gingival lesion. Early detection and management of GO is imperative to allow patients to continue life-prolonging therapy with minimal morbidity. The purpose of this study was threefold: firstly, to determine the prevalence and incidence of GO under the administration of CsA and Tacrolimus; secondly, to assess the correlation between periodontal status before and after periodontal therapy and medications on progression or recurrence of DIGO; and finally, to analyse the effect of immunosuppressant in association to the channel blocker agents on the onset and progression of gingival enlargement. We compared seventy-two renal transplant patients, including 33 patients who were receiving CsA, of which 25% were also receiving nifedipine and 9.72% also receiving amlodipine, and 39 patients who were receiving tacrolimus, of which 37.5% were also receiving nifedipine and 5.55% also receiving amlodipine, aged between 35 and 60 years. Medical and pharmacological data were recorded for all patients. Clinical periodontal examination, in order to establish the inflammatory status and degree of gingival enlargement, was performed at baseline (T0), 3 months (T1), 6 months (T2), and 9 months (T3). All patients were subjected to periodontal treatment. Statistically significant correlation between the reduction of the mean value of periodontal indices and degree of gingival hyperplasia at the three times was revealed. The prevalence of GO in patients taking cyclosporine was higher (33.3%) in comparison with those taking tacrolimus (14.7%). In accordance with previous studies, this trial highlighted the clinical significance of the pathological substrate on stimulating drug-induced gingival lesion, confirming the key role of periodontal inflammation in pathogenesis of gingival enlargement, but did not confirm the additional effect of calcium-channel blocker drugs in inducing gingival enlargement.

Thrombin Activates Latent TGFβ1 via Integrin αvβ1 in Gingival Fibroblasts

Transforming growth factor β (TGFβ) regulates cell proliferation, differentiation, migration, apoptosis, and extracellular matrix production. It also plays a pivotal role in the pathogenesis of gingival overgrowth. Thrombin is a key player in tissue repair, remodeling, and fibrosis after an injury, and it exerts profibrotic effects by activating protease-activated receptors. Connective tissue growth factor (CTGF or CCN2) modulates cell adhesion, migration, proliferation, matrix production, and wound healing. It is overexpressed in many fibrotic disorders, including gingival overgrowth, and it is positively associated with the degree of fibrosis in gingival overgrowth. In human gingival fibroblasts, we previously found that TGFβ1 induced CCN2 protein synthesis through c-jun N-terminal kinase and Smad3 activation. Thrombin stimulates CCN2 synthesis through protease-activated receptor 1 and c-jun N-terminal kinase signaling. Curcumin inhibited TGFβ1- and thrombin-induced CCN2 synthesis. In this study, we demonstrated that thrombin and protease-activated receptor 1 agonist SFLLRN induced latent TGFβ1 activation and Smad3 phosphorylation in human gingival fibroblasts. Pretreatment with a TGFβ-neutralizing antibody, TGFβ type I receptor inhibitor SB431542, and Smad3 inhibitor SIS3 inhibited approximately 86%, 94%, and 100% of thrombin-induced CCN2 synthesis, respectively. Furthermore, blocking integrin subunits αv and β1 with antibodies effectively inhibited SFLLRN-induced Smad3 phosphorylation and CCN2 synthesis and increased activated TGFβ1 levels; however, similar effects were not observed for integrins αvβ3 and αvβ5. These results suggest that protease-activated receptor 1–induced CCN2 synthesis in human gingival fibroblasts is mediated through integrin αvβ1–induced latent TGFβ1 activation and subsequent TGFβ1 signaling. Moreover, curcumin dose dependently decreased thrombin-induced activated TGFβ1 levels. Curcumin-inhibited thrombin-induced CCN2 synthesis in human gingival fibroblasts is caused by the suppression of latent TGFβ1 activation.

NADPH Oxidase 4 Mediates TGFβ1-induced CCN2 in Gingival Fibroblasts

Transforming growth factor β (TGFβ) plays a central role in the pathogenesis of gingival overgrowth (GO). Connective tissue growth factor (CTGF; or CCN2) is induced by TGFβ in human gingival fibroblasts (HGFs) and is overexpressed in GO tissues. CCN2 creates an environment favorable for fibrogenesis and is required for the maximal profibrotic effects of TGFβ. We previously showed that Src, JNK, and Smad3 mediate TGFβ1-induced CCN2 protein expression in HGFs. Moreover, Src is an upstream signaling transducer of JNK and Smad3. Recent studies suggested that NADPH oxidase (NOX)–dependent redox mechanisms are involved in mediating the profibrotic effects of TGFβ. In this study, we demonstrated that TGFβ1 upregulated NOX4 protein expression and increased reactive oxygen species (ROS) production in HGFs. Genetic or pharmacologic targeting of NOX4 abrogated TGFβ1-induced ROS production; Src, JNK, and Smad3 activation; and CCN2 and type I collagen protein expression in HGFs. Our results indicated that NOX4-derived ROS play pivotal roles in activating Src kinase activity leading to the activation of canonical (Smad3) and noncanonical (JNK) cascades that cooperate to attain maximum CCN2 expression. Furthermore, we demonstrated that curcumin significantly inhibited the TGFβ1-induced NOX4 protein expression in HGFs. Curcumin potentially qualifies as an agent to control GO by suppressing TGFβ1-induced NOX4 expression in HGFs.

Verruciform Xanthoma in Severe Phenytoin‐Induced Gingival Overgrowth: A Case Report

Introduction: Phenytoin is involved in drug‐induced gingival overgrowth (GO), with a prevalence rate reaching 50%. In the literature, tumorigenic implication has been discussed with this form of hyperplasia with considerable controversy. To the author's knowledge, this is the first report since 1971 of a combined phenytoin‐induced hyperplasia with verruciform xanthoma (VX). The importance of differentiating this lesion from classic hyperplasia is emphasized in this case report.Case Presentation: A 23‐year‐old male presented with an advanced case of GO attributable to prolonged intake of phenytoin. Oral examination showed total coverage of the dentition, with one unusual cauliflower‐like lesion. Surgery was performed and a biopsy was taken. Histopathologic examination revealed the diagnosis of VX. No recurrence of the disease was evident 12 months after therapy.Conclusions: The definitive pathogenesis of GO and VX is under discussion and some similarities and possible immunologic interactions that might determine the correct sequence of events can be found. The most relevant differential diagnosis of VX is squamous cell carcinoma, which needs to be detected as early as possible. Although no malignancy was found in this case, VX could be a potentially premalignant lesion.

Curcumin Inhibits TGFβ1-induced CCN2 via Src, JNK, and Smad3 in Gingiva

Transforming growth factor β (TGFβ) is a key regulator associated with the pathogenesis of gingival overgrowth (GO). Connective tissue growth factor (CTGF/CCN2) is overexpressed in GO tissues. CCN2 promotes and sustains fibrosis initiated by TGFβ. Previous studies have shown that JNK and Smad3 activation is required for TGFβ-induced CCN2 expressions in human gingival fibroblasts (HGFs). In this study, we have found that Src is a major signaling mediator for TGFβ-induced CCN2 expressions in HGFs. Pre-treatment with 2 Src kinase inhibitors (PP2, Src inhibitor-1) significantly reduced TGFβ1-induced CCN2 synthesis and JNK and Smad3 activation in HGFs. These results suggest that Src is an upstream signaling transducer of JNK and Smad3 with respect to TGFβ1-stimulated CCN2 expression in HGFs. We further found that curcumin significantly abrogated the TGFβ1-induced CCN2 in HGFs by inhibiting the phosphorylations of Src, JNK, and Smad3. Furthermore, curcumin inhibited TGFβ1-induced HGF migration and α-SMA expression. Curcumin potentially qualifies as a useful agent for the control of GO.

Gingival Crevicular Fluid Osteocalcin, N‐Terminal Telopeptides, and Calprotectin Levels in Cyclosporin A–Induced Gingival Overgrowth

The aim of this cross-sectional study is to investigate gingival crevicular fluid (GCF) osteocalcin, cross-linked N-terminal telopeptide (NTx), and calprotectin levels in cyclosporin A (CsA)-induced gingival overgrowth (GO). Forty medicated patients with CsA including 20 with GO (CsA GO+), 10 without GO (CsA GO-), 10 with GO and chronic periodontitis (CsA CP) and 60 patients with CP alone, 20 patients with gingivitis, and 20 healthy patients were enrolled. Probing depth, clinical attachment level, plaque index, and papillary bleeding index were recorded. GCF calprotectin, osteocalcin, and NTx levels were analyzed by enzyme-linked immunosorbent assay. Parametric tests were used for statistical analysis. The CsA GO+ and CP groups had significantly lower GCF osteocalcin levels and osteocalcin/NTx ratio than the healthy group, whereas GCF osteocalcin levels and osteocalcin/NTx ratio in the gingivitis group were higher than the CsA GO+, CsA GO-, CsA CP, and CP groups (P <0.05). The CP group had elevated GCF calprotectin levels compared to the other study groups (P <0.05). The CsA GO+ and CsA GO- groups also had higher GCF calprotectin levels compared to the CsA CP, gingivitis, and healthy groups (P <0.05). Increased GCF calprotectin and decreased GCF osteocalcin levels in the CsA GO+ and CsA GO- groups might suggest that CsA plays a role on the levels of these markers. The similarity of GCF osteocalcin, NTx, and calprotectin levels in the CsA GO+ and CsA GO- groups might suggest that these molecules are not involved in the pathogenesis of GO.

Phenytoin-induced gingival overgrowth: a review of the molecular, immune, and inflammatory features.

Gingival overgrowth (GO) is a side effect associated with some distinct classes of drugs, such as anticonvulsants, immunosuppressant, and calcium channel blockers. GO is characterized by the accumulation of extracellular matrix in gingival connective tissues, particularly collagenous components, with varying degrees of inflammation. One of the main drugs associated with GO is the antiepileptic phenytoin, which affects gingival tissues by altering extracellular matrix metabolism. Nevertheless, the pathogenesis of such drug-induced GO remains fulfilled by some contradictory findings. This paper aims to present the most relevant studies regarding the molecular, immune, and inflammatory aspects of phenytoin-induced gingival overgrowth.

Immunohistochemical Analysis of Inducible and Endothelial Forms of Nitric Oxide Synthase in Cyclosporin A‐Induced Gingival Overgrowth

The contribution of nitric oxide (NO) to immune response and matrix degradation in the periodontal environment suggests a role for NO and NO-synthase (NOS) activity in the pathogenesis of cyclosporin A (CsA)-induced gingival overgrowth (GO). However, current knowledge on this topic is limited to experimental animal studies. The present study was undertaken on the basis of a hypothesis whether altered nitrite/nitrate levels in gingival crevicular fluid (GCF) and endothelial NOS (eNOS) and inducible NOS (iNOS) immunoreactivity in gingiva of CsA-treated patients contribute to the pathogenesis of CsA-induced GO. Twenty-four CsA-medicated renal transplant patients with GO (GO+; n = 12) or without GO (GO-; n = 12), 10 gingivitis, and 10 healthy subjects were included in the study. GCF samples from two proximal sites facing interdental papilla were collected, and papilla was excised. iNOS and eNOS were determined by immunohistochemistry. GCF nitrite/nitrate levels were analyzed based on the Griess reaction. Weak iNOS immunostaining was observed in the healthy and GO- groups. In the gingivitis and GO+ groups, iNOS immunostaining significantly increased in connective tissue. Epithelial immunostaining of iNOS was localized to basal keratinocytes and the lower layer of stratum (str.) spinosum in the gingivitis group. In the GO+ group, iNOS immunostaining was differentially localized to keratinocytes of str. superficiale but considerably decreased in the str. basale. Weak eNOS immunostaining was found in the healthy and GO- groups, whereas higher immunostaining was observed in the gingivitis and GO+ groups. No intergroup differences were observed regarding nitrite/nitrate levels in GCF. CsA differentially upregulated iNOS, but not eNOS, in overgrown gingiva, which may play a pivotal role in the pathogenesis of CsA-induced GO.

Efficacy of AZM therapy in patients with gingival overgrowth induced by Cyclosporine A: a systematic review.

BackgroundIn daily clinical practice of a dental department it's common to find gingival overgrowth (GO) in periodontal patients under treatment with Cyclosporine A (CsA). The pathogenesis of GO and the mechanism of action of Azithromycin (AZM) are unclear. A systematic review was conducted in order to evaluate the efficacy of Azithromycin in patients with gingival overgrowth induced by assumption of Cyclosporine A.MethodsA bibliographic search was performed using the online databases MEDLINE, EMBASE and Cochrane Central of Register Controlled Trials (CENTRAL) in the time period between 1966 and September 2008.ResultsThe literature search retrieved 24 articles; only 5 were Randomised Controlled Trials (RCTs), published in English, fulfilled the inclusion criteria. A great heterogeneity between proposed treatments and outcomes was found, and this did not allow to conduct a quantitative meta-analysis. The systematic review revealed that a 5-day course of Azithromycin with Scaling and Root Planing reduces the degree of gingival overgrowth, while a 7-day course of metronidazole is only effective on concomitant bacterial over-infection.ConclusionFew RCTs on the efficacy of systemic antibiotic therapy in case of GO were found in the literature review. A systemic antibiotic therapy without plaque and calculus removal is not able to reduce gingival overgrowth. The great heterogeneity of diagnostic data and outcomes is due to the lack of precise diagnostic methods and protocols about GO. Future studies need to improve both diagnostic methods and tools and adequate classification aimed to determine a correct prognosis and an appropriate therapy for gingival overgrowth.

Gingival crevicular fluid transforming growth factor-β 1 in cyclosporine and tacrolimus treated renal transplant patients without gingival overgrowth

Background Gingival crevicular fluid (GCF) levels of transforming growth factor-β 1 (TGF-β 1) have been previously investigated in relation to the pathogenesis of cyclosporine-A (CsA)-induced gingival overgrowth (GO) but no clinical data are available regarding the GCF levels of TGF-β 1 in patients treated with tacrolimus (Tac). However, as gingival inflammation is pronounced at sites of GO and this consequently may lead to an elevation in TGF-β 1 levels the present study aimed to evaluate gingival crevicular fluid (GCF) TGF-β 1 levels in renal transplant patients using CsA or Tac without GO. Methods GCF TGF-β 1 levels were investigated in 30 renal transplant patients without GO medicated with either CsA ( n = 15) or Tac ( n = 15). Sixteen gingivitis patients and 15 periodontally healthy subjects were selected as controls. Periodontal status was evaluated by measuring probing depth, plaque index and papilla bleeding index. The TGF-β 1 levels were analysed by enzyme-linked immunosorbent assay. Results Both CsA and Tac groups had significantly elevated GCF TGF-β 1 total amount compared to gingivitis and healthy groups ( p < 0.008). GCF TGF-β 1 total amount of CsA and Tac groups was similar ( p > 0.008). Gingivitis and healthy groups had also similar GCF TGF-β 1 total amount ( p > 0.008). Conclusions Within the limits of the present data it is unlikely that TGF-β 1 is an exclusive mediator of CsA- or Tac-induced GO. However, pathogenesis of GO is multifactorial and contribution of TGF-β 1 to the interrelations between cytokines and growth factors with fibrogenic potential cannot be disregarded.

Evaluation of Telomerase Activity in Gingival Fibroblasts of Cyclosporine-Treated Patients

Gingival overgrowth (GO) is a common side effect following administration of cyclosporin A (CsA). Various case reports have shown that squamous cell carcinomas could arise in GO induced by CsA and phenytoin. It is also known that human telomerase activated in about 90% of cancers is mainly composed of hTR, hTERT, and TPI. The aim of this study was to investigate the potential role of telomerase activity in the pathogenesis of CsA-induced GO. Included in the study were 9 patients on CsA: 4 with and 5 without GO. Gingival tissues were obtained during gingivectomy or flap procedures; gingival fibroblasts were cultured in Dulbecco’s modified Eagle’s medium (DMEM) supplemented with 10,000 U/mL penicillin, 10 mg/mL streptomycin, 2 mmol/L l-glutamine, and 10% heat-inactivated fetal bovine serum at 37°C under a humidified 95% air virgule 5% CO 2 atmosphere. Quantitative detection of hTERT mRNA was performed with the commercially available LightCycler Telo TAGGG hTERT Quantification Kit using real-time online PCR. The hTERT mRNA expression was positive in one patient, while hTERT mRNA expression was negative in the others. Because results indicated that there may be a relationship between CsA-induced GO and positive telomerase activity, detailed studies should be performed to confirm the present findings.

Apoptosis and Expression of Caspase‐3 in Cyclosporin‐Induced Gingival Overgrowth

The pathogenesis of epithelial thickening in gingival overgrowth remains obscure. Apoptosis plays an important role in maintaining tissue hemostasis. The aim of the present study was to investigate apoptosis via immunohistochemical analyses in cyclosporin A-induced gingival overgrowth tissue samples to determine whether these processes play a role in the pathogenesis of gingival overgrowth. Gingival biopsies (one per person) were harvested from 22 renal transplant recipients (eight men and 14 women; mean age, 36.4 +/- 13.3 years) who had been diagnosed with cyclosporin A-induced gingival enlargement and from 12 systemically healthy persons (seven men and five women; mean age, 27.0 +/- 16.0 years) with plaque-induced gingivitis. Distributions of caspase-3 and apoptosis were determined immunologically. Significant differences were found with regard to caspase-3 levels and the extent of apoptosis between the cyclosporin A group and the control group. Plaque index, gingival index, and probing depths were significantly lower in the control group. The extent of keratinocyte apoptosis and decreased levels of caspase-3 may be an important factor affecting the gingiva of kidney transplant recipients with cyclosporin A-induced gingival overgrowth.

Effect of Cyclosporin A on Apoptosis and Expression of p53 and bcl‐2 Proteins in the Gingiva of Renal Transplant Patients

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. 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. 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. 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.

Immunohistochemical Study of Cyclosporin‐Induced Gingival Overgrowth in Renal Transplant Recipients

Cyclosporin A (CsA) is an immunosuppressant widely used to treat transplant patients and various systemic diseases with immunological components. Gingival overgrowth (GO) is a common side effect of CsA administration; however, the pathogenesis of drug-induced GO is poorly understood. The aim of this study was to evaluate the expression of Ki-67, activation molecules (CD71, CD98), leukocytes activation antigens (CD45, CD45RA, CD50, CD11a, CD162, CD227, CD231), neurothelin (CD147), and novel endothelial cell antigens (B-F45, SCF87, B-D46, B-C44, VJ1/6) in gingival tissue in renal transplant recipients treated with CsA. Tissues from 15 renal transplant patients with significant GO and 10 systemically healthy control subjects with gingivitis were studied. Frozen-section biopsies were stained with monoclonal antibodies specific for the above-mentioned antigens using an indirect immunoperoxidase technique. Comparison of the CsA-treated and control groups revealed no significant differences with respect to expression of Ki-67; CD50; activation molecules; neurothelin; or novel endothelial cell antigens B-D46, B-C44, and VJ1/6. However, expression patterns of CD45, CD45RA, CD11a, CD162, CD227, CD231, B-F45, and SCF87 were significantly different in CsA and control groups. Leukocyte activation antigens play an important role in CsA-induced gingival overgrowth.

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.

High prevalence of Chlamydia pneumoniae infection in cyclosporin A-induced post-transplant gingival overgrowth tissue and evidence for the possibility of persistent infection despite short-term treatment with azithromycin.

Cyclosporin A (CsA) induces gingival overgrowth (GO) in up to a quarter of CsA-treated renal transplant recipients. A short-term therapy with azithromycin effectively reduces GO, indicating a possible involvement of microorganisms in the pathogenesis of CsA-induced GO. We aimed to determine if there could be any relationship between infection with Chlamydia pneumoniae and GO pathogenesis. In addition, we determined the long-term persistence rate of C. pneumoniae infection in residual GO tissue when azithromycin treatment failed to eliminate GO. Chlamydia pneumoniae IgG and IgM antibody titres were measured by microimmunofluorescence technique in sera of kidney recipients with (n = 11) and without (n = 89) GO. GOs were rated and gingivectomies were performed before treatment with 500 mg of azithromycin for 3 days and at months 6 and 12 post-treatment when C. pneumoniae titres were re-evaluated. Nested polymerase chain reaction was performed to identify C. pneumoniae-specific DNA in GO tissues. Results of C. pneumoniae antibody titres from patients with GO were compared with pair-matched controls without GO. Chlamydia pneumoniae IgM titres were elevated in five of 11 patients with GO and in none without GO, whereas the difference of C. pneumoniae IgG titres between patients with GO and pair-matched controls did not reach significance (P<0.57). Chlamydia pneumoniae-specific DNA was found in 10 of 11 GO tissue samples pre-treatment. Azithromycin therapy effectively reduced GO and C. pneumoniae IgM titres. In residual GO, C. pneumoniae-specific DNA remained detectable after 1 year in all GO tissue samples despite azithromycin treatment. The C.pneumoniae IgM titres correlated with GO scores. Chlamydia pneumoniae infection is highly prevalent in CsA-induced GO. The infection can persist over a long period in residual GO despite short-term azithromycin therapy. The results indicate that CsA immunosuppression enhances C. pneumoniae infection rates in non-cardiovascular tissue.

Cyclosporin A upregulates phospholipase C beta1 in fibroblasts from gingival overgrowth.

In an attempt to evaluate the influence of cyclosporin A (CsA) on fibroblast metabolism, the phospholipase C beta1, (PLC beta1) nuclear expression was evaluated in fibroblasts from heart transplantation patients treated with CsA who exhibited gingival overgrowth (GO) and from controls. PLC beta1 was assessed by immunoblotting and immunocytochemistry means. Findings did not show any difference in terms of PLC beta1 expression between the 2 groups when fibroblasts were incubated in media without CsA, while the addition of CsA highly stimulated the fibroblasts from CsA-treated patients compared to controls. The abnormal fibroblastic response in CsA-treated patients was detected both in cells from enlarged gingival sites and in cells from clinically healthy gingival sites. These results do not explain whether the exaggerated reactivity to in vitro CsA is the consequence of a genetically transmitted susceptibility to CsA that identifies those subjects at risk for developing GO, or whether it is a secondary effect of the long-term in vivo exposure to CsA. However, the present data underline the lack of any close relationship between enhanced fibroblast activity and clinical signs of GO and support the hypothesis that some other factors, together with CsA, are involved in the pathogenesis of CsA-induced GO.