Stereologic study of cyclosporin A-induced gingival overgrowth in renal transplant patients

Immunohistochemical Localization of Epithelial Mesenchymal Transition Markers in Cyclosporine A Induced Gingival Overgrowth

INTRODUCTION

Cyclosporine, an immunosuppressive agent used in the management of renal transplant patients is known to produce Drug Induced Gingival Overgrowth (DIGO) as a side effect. Several mechanisms have been elucidated to understand the pathogenesis of DIGO. Recently, epithelial mesenchymal transition has been proposed as a mechanism underlying fibrosis of various organs.

AIM

The aim of the study was to investigate if Epithelial Mesenchymal Transition (EMT) operates in Cyclosporine induced gingival overgrowth.

MATERIALS AND METHODS

The study involved obtaining gingival tissue samples from healthy individuals (n=17) and subjects who exhibited cyclosporine induced gingival overgrowth (n=18). Presence and distribution of E-Cadherin, S100 A4 and alpha smooth muscle actin (α-SMA) was assessed using immunohistochemistry and cell types involved in their expression were determined. The number of α- SMA positive fibroblasts were counted in the samples.

RESULTS

In control group, there was no loss of E-Cadherin and a pronounced staining was seen in the all layers of the epithelium in all the samples analysed (100%). S100 A4 staining was noted in langerhans cells, fibroblasts, endothelial cells and endothelial lined blood capillaries in Connective Tissue (CT) of all the samples (100%) while α - SMA staining was seen only on the endothelial lined blood capillaries in all the samples (100%). However in DIGO, there was positive staining of E-Cadherin only in the basal and suprabasal layers of the epithelium in all the samples (100%). Moreover there was focal loss of E-Cadherin in the epithelium in eight out of 18 samples (44%). A break in the continuity of the basement membrane was noted in three out of 18 samples (16%) on H & E staining.

CONCLUSION

Based on the analysis of differential staining of the markers, it can be concluded that EMT could be one of the mechanistic pathways underlying the pathogenesis of DIGO.

Cyclosporin A and phenytoin modulate inflammatory responses

Gingival overgrowth is a common side-effect of administration of the immunosuppressant cyclosporin A and the anti-epileptic drug phenytoin. While cyclosporin-induced gingival overgrowth is often accompanied by gingival inflammation, phenytoin-induced gingival overgrowth usually forms fibrotic lesions. To determine whether these drugs alter the inflammatory responses of gingival fibroblasts, we investigated the effects of cyclosporin and phenytoin on Toll-like receptor (TLR)-mediated responses to microbial components. In Chinese hamster ovary reporter cell lines, cyclosporin alone triggered signaling, whereas phenytoin down-regulated signaling induced by the TLR2 or TLR4 ligand. In human gingival fibroblasts, cyclosporin alone did not induce evident inflammatory responses, but augmented the expression of CD54 and the production of interleukin (IL)-6 and IL-8 induced by TLR ligands, whereas phenytoin attenuated those responses. Cyclosporin also augmented CD54 expression in gingiva of mice injected with lipopolysaccharide. These results indicated that cyclosporin positively and phenytoin negatively modulated inflammatory responses of human gingival fibroblasts.

Differential gene and protein expression of tissue inhibitors of metalloproteinases (TIMP)-3 and TIMP-4 in gingival tissues from drug induced gingival overgrowth

OBJECTIVES

The purpose of this study was to analyse mRNA expression and protein localization of tissue inhibitors of metalloproteinases (TIMP)-3 and TIMP-4 in gingival tissues removed from drug (calcium-channel blocker) induced gingival overgrowth and periodontitis patients.

DESIGN

Employing RT-PCR, we evaluated TIMP-3 and TIMP-4 mRNA levels of 20 human gingival tissue samples taken from patients suffering gingival overgrowth (GO) and periodontitis (P). Then, using immunohistochemistry we investigated the TIMP-3 and TIMP-4 protein localization of five sample tissues from each group.

RESULTS

TIMP-4 mRNA levels in GO-gingiva tended to be lower than in P-gingiva but the results differed little (p = 0.22). Varying degrees of inflammation in the protein localization of TIMP-3 and TIMP-4 were found. TIMP-4 immunoreactivity (IR) was weak in the endothelial cells, fibroblasts, epithelial basal and parabasal cells while the degree of inflammation differed as well. TIMP-3 and TIMP-4 IR in inflammatory cells, including lymphocytes, plasma cells, and macrophages, were faint and intense respectively. For P-gingiva, both TIMP-3 and TIMP-4 IR expression was weak in the endothelial cells, fibroblasts, basal and parabasal epithelial layers. Expression of TIMP-3 was faint in the inflammatory cells, whereas TIMP-4 IR was strong.

CONCLUSION

Our findings suggest that TIMP-3 and TIMP-4 expression differs in GO and P-gingival tissues, both of which are potentially involved in pathogenesis.

Non-surgical periodontal treatment of cyclosporin A-induced gingival overgrowth: immunohistochemical results

AIM

The present study was planned to analyze the effects of a 12-month non-surgical periodontal treatment on histologic and immunohistochemical features of cyclosporin A (CsA)-induced gingival overgrowth (GO).

MATERIALS AND METHODS

Gingival samples were collected from 21 liver transplant subjects exhibiting CsA-induced GO prior to, and 12 months after non-surgical periodontal therapy including oral hygiene instructions, scaling and 2-month recall appointments, and also from 18 healthy control subjects. Gingival biopsy specimens were stained with hematoxylin-eosin and monoclonal antibodies for vimentin, CD3 (T-lymphocytes), CD20 (B-lymphocytes), CD34 (endothelium) and Ki-67 (fibroblasts proliferation rate), using a streptavidin-biotin-peroxidase complex method.

RESULTS

Total inflammatory cells, gingival vessels and fibroblast proliferation rate demonstrated significant reduction after non-surgical periodontal treatment (P < 0.0001) in overgrown gingiva, while B- and T-lymphocytes remained nearly unchanged (P = 0.61 and 0.33, respectively). At the 12-month evaluation no significant differences were found when comparing the gingival biopsies from CsA-treated patients and those from healthy controls (P > 0.05).

CONCLUSIONS

Control of clinical inflammation by means of non-surgical periodontal treatment results both in lowering of inflammatory infiltrate and in changes in connective tissue composition. Thus, plaque-induced inflammation would seem to modulate the drug-gingival tissue interaction.

CLINICAL RELEVANCE

A strict plaque control program play a pivotal role in the management of transplant patients exhibiting cyclosporin A-GO.

Expression of fibronectin-binding integrins in gingival epithelium in drug-induced gingival overgrowth

BACKGROUND AND OBJECTIVE

Gingival overgrowth is a side-effect of nifedipine and cyclosporin medications. Integrins are transmembrane glycoproteins that mediate cell adhesion, regulate cell proliferation and participate in the regulation of tissue fibrosis. The aim of this study was to investigate whether expression of epithelial cell integrins is linked to the development of drug-induced gingival overgrowth.

MATERIAL AND METHODS

Human gingival biopsies of patients taking nifedipine, cyclosporin, or a combination of both medications, were used. Expression of the alpha5beta1, alphavbeta1 and alphavbeta6 integrins, and of cellular extra domain A of fibronectin, was localized in frozen sections using immunohistochemistry.

RESULTS

The activated conformation of the beta1, alpha5beta1 and alphavbeta6 integrins were more frequently expressed in distinct locations in the oral epithelium in the combined drug group. Cellular extra domain A of fibronectin, a ligand for both alpha5beta1 and alphavbeta6 integrins, was expressed within the connective tissue of all groups. It was also expressed around the basal keratinocytes of the control, nifedipine and cyclosporin-induced gingival overgrowth groups, but not in the combined medication group. No relationship between the presence of inflammation and integrin expression was found.

CONCLUSION

The results indicate that expression of certain integrins is up-regulated in the epithelium of drug-induced gingival overgrowth where they could participate in controlling the formation of elongated rete ridges and tissue fibrosis.

Immunohistochemical Evaluation of Ki-67 Expression and Apoptosis in Cyclosporin A-Induced Gingival Overgrowth

BACKGROUND

This study was planned to evaluate cell division rate and apoptosis by immunohistochemical and in situ hybridization techniques in cyclosporin A (CsA)-induced gingival overgrowth tissue samples to determine whether these processes played a role in the pathogenesis of this condition.

METHODS

Fourteen CsA-induced overgrowth tissues from renal transplant recipients, 10 control tissues from patients with plaque-induced gingivitis, and 14 control tissues from systemically and periodontally healthy subjects were evaluated. In patient groups, clinical periodontal recordings and tissue sampling were performed before initiation of any periodontal intervention. Numbers of Ki-67-positive cells/field and apoptotic cells/field in formalin-fixed/paraffin-embedded tissue sections were determined. Data were evaluated by one-way analysis of variance, post hoc Sidak test with modified Bonferroni correction, and Pearson correlation analysis. Three phenytoin- and five nifedipine-induced overgrowth tissues were also processed in the same way, and findings in these tissue specimens were evaluated as case series.

RESULTS

The number of keratinocytes was significantly greater in the CsA-induced gingival overgrowth group than in the healthy control group (P <0.05). Cells labeled by in situ end labeling, namely the apoptotic cells, were significantly fewer in the CsA group than in the gingivitis and healthy control groups (P <0.01). Overall, statistically significant positive correlations were found between the numbers of Ki-67-positive cells and probing depth and hyperplastic, bleeding, and plaque indices (P <0.01). Phenytoin and nifedipine samples exhibited obviously higher expression of Ki-67-positive cells than the CsA, gingivitis, and healthy control groups.

CONCLUSION

Our findings suggest that decreased apoptosis may have a more prominent role than increased cell division in the pathogenesis of CsA-induced gingival overgrowth.

Influence of Cyclosporin A on human gingival keratinocytes in vitro

PURPOSE

Gingival hyperplasia is a well known side effect of Cyclosporine A therapy. The aetiology of this is not totally understood and there is debate whether it is hyperplasia of the gingival epithelium or of the submucosal connective tissue, or both, and what roles play factors like age and gender of the patients, duration and dosage of the drug.

MATERIAL AND METHODS

The influence of different Cyclosporine A concentrations (10(-6) g/ml; 5 x 10(-7) g/ml; 10(-9) g/ml) and of no medication (controls) on growth and proliferation of cultured human gingival keratinocytes was investigated after a culture period of 3, 6 and 9 days. Cell proliferation was assessed by counting anti Ki-67 stained nuclei, cell growth by counting total number of nuclei and by the EZ4U-assay.

RESULTS

There was no significant correlation of the cell proliferation rate and cellular growth with either gender (p > 0.568) or duration of medication (p > 0.876); but Cyclosporine A concentration showed a highly significant influence on cellular growth (p = 0.0001). Inhibition of cell growth was dependent on drug dosage, but a low concentration of 10(-9) g/ml even stimulated cell growth.

CONCLUSIONS

There is evidence that Cyclosporine A in low concentrations (10(-9) g/ml as applied in long-term therapy) stimulates gingival keratinocyte growth and therefore might be related to hyperplasia of the gingiva. However, high Cyclosporine A concentrations may inhibit cell growths and factors like gender of the patient did not show any influence in-vitro.

Elevated levels of gene expression for collagen and decorin in human gingival overgrowth

OBJECTIVES

It has been demonstrated that extracellular matrix molecules are involved in cyclosporine-induced gingival overgrowth (GO). However, for many of these molecules, it remains unclear whether their abundance is modulated on the protein and gene expression level.

MATERIAL AND METHODS

To contribute to this clarification, we have analysed the protein and mRNA expression of type-I collagen (COL1) and decorin (DC) in native specimens obtained from five patients with GO, and matched normal tissue using indirect immunofluorescence (IIM), in situ hybridization (ISH) and quantitative polymerase chain reaction (PCR).

RESULTS

IIF revealed a largely co-localized although remarkably increased abundance for COL1 and DC in GO. This increase coincided with an up-regulated gene expression observed for both molecules, as detected by ISH and quantitative PCR.

CONCLUSIONS

Analysis of our data clearly demonstrates elevated levels for COL1 and DC and shows for the first time in native human tissue that involvement of these genes in GO is not confined to the protein level but also includes the transcriptional level.

Synergism between nifedipine and cyclosporine A on the incorporation of [35S]sulfate into human gingival fibroblast cultures in vitro

BACKGROUND AND OBJECTIVE

We assessed the effects of cyclosporine A and nifedipine on the in vitro incorporation of [(35)S]sulfate into gingival fibroblast cell cultures derived from responder and nonresponder subjects who had received an organ transplant followed by a therapeutic regimen using a combination of those drugs.

MATERIAL AND METHODS

Gingival fibroblasts were isolated from responder and nonresponder subjects and maintained in vitro. Prior to cell harvest, gingival interleukin-1beta concentrations were determined by enzyme-linked immunosorbent assay (ELISA). Cells were untreated or exposed to either 10(-7)-10(-10) m nifedipine or 100-500 ng/ml cyclosporine A. Incorporation of [(3)H]proline or [(35)S]sulfate into the cell cultures was determined by liquid scintillation analysis. In addition, the effects of 400 ng/ml cyclosporine A + 10(-7) m nifedipine and 400 ng/ml cyclosporine A + 10(-10) m nifedipine on incorporation of [(35)S]sulfate into the cell cultures was determined. Data were compared by factorial analysis of variance (anova) and a posthoc Tukey's test.

RESULTS

Gingiva from responders contained significantly more interleukin-1beta than gingiva from nonresponders (p < 0.01). The cell cultures derived from responders incorporated significantly more [(35)S]sulfate than those derived from nonresponders following exposure to either cyclosporine A or 10(-7) m nifedipine. In addition, the exposure of fibroblasts derived from gingival overgrowth to either 400 ng/ml cyclosporine A + 10(-7) m nifedipine or 400 ng/ml cyclosporine A + 10(-10) m nifedipine significantly increased or decreased, respectively, the incorporation of [(35)S]sulfate into the cultures.

CONCLUSION

The therapeutic combination of cyclosporine A and nifedipine could be a significant risk factor for gingival overgrowth in subjects susceptible to either agent. The mechanism for overgrowth could include edema secondary to increased sulfated-glycosaminoglycan (sGAG) synthesis by fibroblasts, but further investigation is required.

Analysis of proliferative activity in oral gingival epithelium in immunosuppressive medication induced gingival overgrowth

Background

Drug-induced gingival overgrowth is a frequent adverse effect associated principally with administration of the immunosuppressive drug cyclosporin A and also certain antiepileptic and antihypertensive drugs. It is characterized by a marked increase in the thickness of the epithelial layer and accumulation of excessive amounts of connective tissue. The mechanism by which the drugs cause gingival overgrowth is not yet understood. The purpose of this study was to compare proliferative activity of normal human gingiva and in cyclosporine A-induced gingival overgrowth.

Methods

Gingival samples were collected from 12 generally healthy individuals and 22 Cyclosporin A-medicated renal transplant recipients. Expression of proliferating cell nuclear antigen was evaluated in formalin-fixed, paraffin-embedded gingival samples using an immunoperoxidase technique and a monoclonal antibody for this antigen.

Results

There were differences between the Cyclosporin A group and control group in regard to proliferating cell nuclear antigen and epithelial thickness. In addition, the degree of stromal inflammation was higher in the Cyclosporin A group when compared with the control group.

Conclusion

The results suggest that the increased epithelial thickness observed in Cyclosporin A-induced gingival overgrowth is associated with increased proliferative activity in keratinocytes.

Increased Expression of Vascular Endothelial Growth Factor in Cyclosporin A-Induced Gingival Overgrowth in Rats

BACKGROUND

Gingival overgrowth is a side effect associated with cyclosporin A (CsA) therapy. The lesion is characterized by increased epithelial thickness, enlargement of connective tissue, and increased vascularization. The aim of this experimental study was to examine the role of vascular endothelial growth factor (VEGF) in the pathogenesis of CsA-induced gingival overgrowth.

METHODS

Twenty male Wistar rats were divided into two groups of 10 animals each. For the development of gingival overgrowth, one group received CsA therapy subcutaneously in a daily dose of 10 mg/kg for 60 days, and the other group was used as a control. At the end of the experimental period, rats were subsequently decapitated, and the mandibles with the surrounding gingiva and soft tissue were removed. Half of each sample was used for histomorphometric analysis, and the other half was used for biochemical analysis. Histomorphometric analysis included the measurements of the number and diameter of blood vessel profiles under a microscope, and biochemical analysis included the assessment of VEGF concentration by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The histomorphometric findings showed that the number of blood vessel profiles increased in the CsA group compared to the control group (P <0.001), although the increase in the diameter of blood vessel profiles was not significant (P >0.05). The biochemical findings showed that in vivo VEGF expression was higher in the CsA group compared to the control group (P <0.001).

CONCLUSION

The results of this study suggest that increased VEGF expression may be associated with the pathogenesis of CsA-induced gingival overgrowth.

Gingival tissue proteoglycan and chondroitin-4-sulphate levels in cyclosporin A-induced gingival overgrowth and the effects of initial periodontal treatment

OBJECTIVES

Cyclosporin A (CsA) is a potent immunosuppressive drug used in organ transplant patients to prevent graft rejection. CsA-induced gingival overgrowth is one of the side effects of this drug and its pathogenesis is still unclear. The present study was planned to comparatively analyse total proteoglycan (PG) and chondroitin-4-sulphate (C4S) levels in CsA-induced overgrown gingival tissue samples obtained before and after initial periodontal treatment and to compare these findings with the situation in healthy gingiva.

MATERIAL AND METHODS

Gingival tissue samples were obtained from nine patients with CsA-induced gingival overgrowth before and 4 weeks after initial periodontal treatment including oral hygiene instruction and scaling and also from 10 healthy control subjects. Total PG and C4S levels were determined by biochemical techniques. PG levels were analysed using modified Bitter and Muir method. C4S assay was carried out using chondroitin sulphate lyase AC and chondroitin-6 sulphate sulphohydrolase enzymes. The results were tested statistically using non-parametric tests.

RESULTS

All clinical measurements in the CsA-induced gingival overgrowth group demonstrated significant reductions 4 weeks after initial periodontal treatment (p<0.05). There was no significant difference between the levels of baseline total PG in CsA-induced gingival overgrowth and healthy control groups (p>0.05). The gingival tissue levels of PG in CsA-induced gingival overgrowth group decreased significantly 4 weeks after treatment (p=0.043). Gingival tissue C4S levels in the overgrowth group were significantly higher than the healthy control group at baseline (p=0.000). C4S levels of the overgrowth group were significantly reduced after treatment (p=0.033), but these levels were still significantly higher than the healthy control group (p=0.000).

CONCLUSION

The observed prominent increase in gingival tissue C4S levels may be interpreted as a sign of an increase in C4S synthesis in CsA-induced gingival overgrowth. Furthermore, remission of clinical inflammation by means of initial periodontal treatment had a positive effect on tissue levels of these extracellular matrix molecules.

Gene Expression of Extracellular Matrix Proteoglycans in Human Cyclosporin-Induced Gingival Overgrowth

BACKGROUND

Gingival overgrowth is one of the side effects associated with the systemic use of cyclosporin A (CsA). In vitro studies on the extracellular matrix of gingival tissues have demonstrated an altered composition, particularly an accumulation of proteoglycans and collagen. We investigated the gene expression of extracellular matrix proteoglycans in CsA-induced gingival tissue alterations.

METHODS

mRNA expression of the proteoglycans perlecan, decorin, biglycan, and versican was analyzed by reverse transcription polymerase chain reaction (RT-PCR) in gingival samples obtained from 12 individuals, six with CsA-induced gingival overgrowth (CsA group) and six with a normal gingiva (control group). The RT-PCR products were subjected to 1% agarose gel electrophoresis containing ethidium bromide and analyzed qualitatively and semiquantitatively by densitometry. Density values were normalized by determining the expression of the housekeeping gene beta-actin in the same sample. Groups were compared by the Student's t test.

RESULTS

Perlecan expression showed a marked increase (54%) in the CsA group compared to the control group (P < 0.01), while no significant differences were observed for the other proteoglycans.

CONCLUSION

CsA-induced gingival overgrowth seems to be associated with increased expression of perlecan, a typical basement membrane proteoglycan, but not decorin, biglycan, or versican.

Oral health in liver transplant children administered cyclosporin A or tacrolimus

BACKGROUND

Immunosuppression by cyclosporin A (CsA) is associated with adverse side-effects, including nephrotoxicity, neurotoxicity and gingival overgrowth. Tacrolimus (TAC/FK506) is a new immunosuppressive agent, recently approved for use in solid-organ transplants. The mode of action of TAC is similar to that of CsA and the toxicity profile of CsA is duplicated by TAC. The effect of TAC on the gingival tissue is not yet conclusive.

SAMPLE

Gingival overgrowth was assessed in 30 liver transplant children, 20 boys and 10 girls, aged 2-19 years. Seventeen children (10 boys, seven girls) were on a CsA-based immunosuppressive regimen whereas 13 children (10 boys, three girls) were on TAC for at least 1 year (mean 4.3 +/- 2.7).

RESULTS

In the CsA group, 35% of children exhibited gingival overgrowth characterized by one or more units with increased sulcus probing depth (> or = 4 mm), i.e. pseudopockets. In contrast to the CsA group, none of the children in the TAC group exhibited gingival overgrowth. The occurrence of enamel hypoplasia was observed in 11 children (36%) and enamel opacities were found in 23 children (76%). Six of the 12 children (50%) with hyperbilirubinaemia biliary atresia exhibited a marked greenish discoloration of the teeth. Caries experience (dmft/DMFT) among these children was 2.0 +/- 2.8.

CONCLUSION

No difference in caries experience or enamel defect was observed between the CsA and TAC group.

Mitotic activity of keratinocytes in nifedipine- and immunosuppressive medication-induced gingival overgrowth

BACKGROUND

The purpose of the study was to compare mitotic activity in the basal cell layer of normal human gingiva and in nifedipine- and immunosuppressive medication-induced gingival overgrowth.

METHODS

Gingival samples were collected from 19 generally healthy individuals, 12 nifedipine-medicated cardiac patients, and 22 immunosuppression-medicated (azathioprine, prednisolone, and cyclosporin A) organ transplant recipients. The transplant recipients were divided into those not taking nifedipine and those taking nifedipine. Cryostat sections were stained with monoclonal antibody for Ki-67, using an avidin-biotin-enzyme complex method. The mitotic activities of epithelial cells were determined as percentages of Ki-67 labeled cells in relation to total numbers of epithelial cells in the basal layer of oral, oral sulcular, and sulcular epithelium.

RESULTS

Mitotic activities were significantly higher in all 3 medication groups in the oral epithelium (P < or =0.003), and in the immunosuppression group in the sulcular epithelium (P= 0.032) than in the controls. In the oral sulcular epithelium, mitotic activity was fairly similar in all medication groups. In the nifedipine group a significant negative correlation was found between duration of nifedipine medication and the percentage of Ki-67 labeled cells in the oral epithelium (P= 0.025).

CONCLUSIONS

The results suggest that the increased epithelial thickness observed in nifedipine- and cyclosporin A-induced gingival overgrowth is associated with increased mitotic activity, especially in the oral epithelium.

Cyclosporin A-induced gingival overgrowth in the rat: a histological, ultrastructural and histomorphometric evaluation

This investigation was undertaken to further study cyclosporin A (CsA)-induced gingival overgrowth. Thirty mg/kg/d of vehicle or CsA solutions were given orally to 6-wk-old male Sprague-Dawley rats. After 4, 9, 14 and 19 wk 2 control and 2 experimental rats were anaesthetized, tissues fixed by intracardiac perfusion of fixative solution and jaws processed for Epon inclusion. Histological and ultrastructural studies conducted in a gingival portion (free gingiva) revealed the presence of hyalinization areas and of multinucleated cells (MCs) containing collagen fibrils (connective tissue), of amorphous areas and disorders of keratinization (epithelia). Histomorphometric evaluation indicated that in the CsA rats the mean cross-sectional area of the free gingiva was 2.52-fold increased compared to the controls. The connective tissue comprised 41.43% of this area (instead of 31.49% in controls). Additional histomorphometric evaluation was performed in 3 groups of free gingival portions: control (C group), CsA-non-respondent (CsA-nR) and CsA-respondent (CsA-R). The cross-sectional gingival areas studied were slightly lower than the mean area of all the control sites previously defined (groups C and CsA-nR) or showed the higher degrees of enlargement (CsA-R). In the CsA-R group the mean cross-sectioned area of the vessel profiles was increased and the number of fibroblast profiles decreased. In the CsA-nR group the number of vessel profiles and that of MCs profiles were increased. In the epithelia of the CsA-R group were increased (a) keratinized epithelia: thickness; thickness of the inner and of the outer compartments; surface area of spinous cell profiles; (b) oral gingival epithelium: number of cell layers (inner compartment); (c) oral sulcular epithelium: surface area of granular cell profiles; (d) junctional epithelium: thickness; number of cell layers. These results indicate that (a) the CsA induced modifications are not limited to enlarged gingiva (b) the overgrowth of the GCT is the result of a vasodilatation and of an increase in the volume of the extracellular matrix and (c) the increase of the epithelial thickness is mainly the result of a cell hypertrophy in the keratinized epithelia and of a cell hyperplasia in the junctional epithelium.

Renal function in cyclosporine-treated pediatric renal transplant recipients in relation to gingival overgrowth

BACKGROUND

Transplant immunosuppression using cyclosporine (CsA) leads to renal dysfunction as well as gingival overgrowth. The underlying alteration in both these lesions is characterized by an excessive accumulation of extracellular matrix components (fibrosis). To investigate the relationship between CsA-induced nephrotoxicity and gingival overgrowth, the renal function as well as the occurrence of gingival overgrowth was evaluated in pediatric renal transplant recipients: 38 boys and 30 girls, ranging in age from 2 to 20 years, who had been on a CsA-based immunosuppressive regimen for at least 12 months.

METHODS

Gingival overgrowth was determined on the basis of measurements of sulcus depth and was diagnosed as positive when the probing depth was > or = 4 mm without exhibiting a loss of periodontal attachment. Renal function tests were performed using inulin and para-aminohippuric acid clearances for evaluating glomerular filtration rate, effective renal plasma flow (ERPF), and filtration fraction (FF).

RESULTS

Nineteen percent of the children exhibited gingival overgrowth. The occurrence of gingival overgrowth was positively related (P<0.05) to the mean oral daily dose of CsA, the mean CsA trough blood level, and concomitant administration of nifedipine. The children who were on antihypertensive treatment exhibited lower ERPF and significantly higher FF than the normotensive children. The mean FF value was significantly higher (P<0.05) in the children with gingival overgrowth than in those without gingival overgrowth, whereas glomerular filtration rate and ERPF did not differ between the two groups.

CONCLUSIONS

The study suggests that there is a positive correlation between the degree of gingival enlargement and changes in renal function expressed as filtration fraction.

Cyclosporin A upregulates prostaglandin E2 production in human gingival fibroblasts challenged with tumor necrosis factor alpha in vitro

The effect of cyclosporin A (CsA) on prostaglandin E2 (PGE2) production in human gingival fibroblasts challenged with tumor necrosis factor alpha (TNF-alpha) was studied. TNF-alpha (1-100 ng/ml) dose-dependently stimulated PGE2 formation in 24 h cultures. CsA (1-100 ng/ml) did not induce PGE2 formation itself but potentiated TNF-alpha induced PGE2 formation in gingival fibroblasts in a manner dependent on the concentrations of both CsA and TNF-alpha. TNF-alpha (10 ng/ml) stimulated the release of [3H]-arachidonic acid (AA) from prelabelled fibroblasts that was potentiated by CsA (100 ng/ml). Addition of exogenous unlabelled AA (5-20 microM/ml) to the cells resulted in enhanced PGE2 formation that was not potentiated by CsA (100 ng/ml). Furthermore, CsA (100 ng/ml) did not further increase the level of cyclooxygenase-2 mRNA induced by TNF-alpha (10 ng/ml), although PGE2 formation was enhanced. The results indicate that CsA and TNF-alpha act in concert on PGE2 formation in gingival fibroblasts, which may be of importance in the pathogenesis of gingival overgrowth induced by the drug.