Immunohistochemical study of 30 cases of cyclosporin A-induced gingival overgrowth

Effects of cyclosporine and phenytoin on biomarker expressions in gingival fibroblasts of children and adults: an in vitro study

BACKGROUND

Both phenytoin (PhT) and cyclosporine (CsA) have been related to gingival overgrowth, but the presence and incidence of cytokines in gingival tissues are associated with different mechanisms. On the basis of a few epidemiologic data, children are more prone to have gingival overgrowth than adults and there is no obvious plausibility to justify this difference. The aim of this study was to investigate the effect of PhT and CsA on the some biological marker expression and compare it among adults and children.

METHODS

Gingival fibroblasts that had been harvested from adults and children with normal gingiva were incubated with CsA and PhT and then cultured for 48 h. Matrix metalloproteinases (MMP-1 and MMP-2), tissue inhibitor of metalloproteinases (TIMP), collagen (CoL), elastin (Eln), lysyl oxidase (Lysyl), cathepsin (Cat) L and B, and mRNA levels in culture were determined by reverse transcription polymerase chain reaction. The amounts of transforming growth factor-β (TGF-β) and epidermal growth factor (EGF) were assessed by enzyme-linked immunosorbent assay.

RESULTS

CsA and PhT stimulated TGF-β and Cat B production and inhibited expression of MMP-1 by fibroblasts. CsA suppressed TIMP in children, but PhT stimulated its expression. In adults, both CSA and PHT increased TGF-β, Lysyl, and EGF levels. CsA reduced Eln level, whereas PhT increased it.

CONCLUSIONS

The results suggest that CsA and PhT have different effects on biogene marker expression in adults and children, or drug-induced gingival overgrowth is affected by different cellular pathways in children in contrast to that in adults. It seems that in children the MMP-1/TIMP system, and in adults the Lysyl/Eln pathway, plays an important role in impaired CoL metabolism.

Suppression of LPS-induced matrix-metalloproteinase responses in macrophages exposed to phenytoin and its metabolite, 5-(p-hydroxyphenyl-), 5-phenylhydantoin

BACKGROUND

Phenytoin (PHT) has been reported to induce gingival (gum) overgrowth (GO) in approximately 50% of patients taking this medication. While most studies have focused on the effects of PHT on the fibroblast in the pathophysiology underlying GO, few studies have investigated the potential regulatory role of macrophages in extracellular matrix (ECM) turnover and secretion of proinflammatory mediators. The aim of this study was to evaluate the effects of PHT and its metabolite, 5-(p-hydroxyphenyl-), 5-phenylhydantoin (HPPH) on LPS-elicited MMP, TIMP, TNF-α and IL-6 levels in macrophages.

METHODS

Human primary monocyte-derived macrophages (n = 6 independent donors) were pretreated with 15-50 μg/mL PHT-Na+ or 15-50 μg/mL HPPH for 1 hour. Cells were then challenged with 100 ng/ml purified LPS from the periodontal pathogen, Aggregatibacter actinomycetemcomitans. Supernatants were collected after 24 hours and levels of MMP-1, MMP-2, MMP-3, MMP-9, MMP-12, TIMP-1, TIMP-2, TIMP-3, TIMP-4, TNF-α and IL-6 determined by multiplex analysis or enzyme-linked immunoadsorbent assay.

RESULTS

A dose-dependent inhibition of MMP-1, MMP-3, MMP-9, TIMP-1 but not MMP-2 was noted in culture supernatants pretreated with PHT or HPPH prior to LPS challenge. MMP-12, TIMP-2, TIMP-3 and TIMP-2 were not detected in culture supernatants. High concentrations of PHT but not HPPH, blunted LPS-induced TNF-α production although neither significantly affected IL-6 levels.

CONCLUSION

The ability of macrophages to mediate turnover of ECM via the production of metalloproteinases is compromised not only by PHT, but its metabolite, HPPH in a dose-dependent fashion. Further, the preferential dysregulation of macrophage-derived TNF-α but not IL-6 in response to bacterial challenge may provide an inflammatory environment facilitating collagen accumulation without the counteracting production of MMPs.

Cyclosporine A-induced neck fibrosis in a patient with adult-onset Still's disease

Cyclosporine A (CsA) is an immunosuppressive agent used for the prevention of graft rejection during organ and bone marrow transplantation. CsA is also used for the treatment of various inflammatory rheumatic diseases. Although different side effect profiles have been reported, nephrotoxicity, renal vascular damage, hypertension, and gingival hypertrophy are among the most commonly encountered side effects. The development of massive fibrosis in the neck associated with CsA in a 30-year-old male patient with Still's disease is presented herein. Significant regression was observed after the discontinuation of CsA.

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.

Platelet-derived growth factor (PDGF) isoform and PDGF receptor expression in drug-induced gingival overgrowth and hereditary gingival fibrosis

OBJECTIVE

To investigate possible associations between platelet-derived growth factor (PDGF), PDGF receptor expression and macrophages in drug-induced and hereditary gingival overgrowth.

MATERIALS AND METHODS

Tissues from patients with drug-induced gingival overgrowth (DIGO) (n = 10) and hereditary gingival fibrosis (n = 10) were studied and compared with 'control' gingiva (n = 10). Expression of PDGF and its alpha and beta receptors was investigated immunohistochemically and by RT-PCR. Macrophages were identified by immunostaining for CD68.

RESULTS

PDGF isoforms and receptors were detected in most cells within all specimens. There were no differences in the numbers of macrophages, or fibroblasts expressing PDGF or receptors, between groups. The level of PDGF expression by fibroblasts, determined by absorbance measurements, was similar between groups for PDGF A. Significantly lower levels of total PDGF and the receptors were detected in drug-induced overgrowth compared to those in hereditary fibrosis (P < 0.004) and control specimens (P < 0.034). All specimens expressed mRNA for PDGF A, PDGF B and alpha and beta receptors.

CONCLUSIONS

These data do not support a pivotal role for macrophage-derived PDGF B in the pathogenesis of DIGO. They suggest that fibroblasts in drug-induced lesions have a lowered capacity to produce, and respond to, PDGF, a property not shared by fibroblasts associated with hereditary fibrosis.

Cyclosporin A specifically affects nuclear PLCbeta1 in immunodepressed heart transplant patients with gingival overgrowth

One of the most commonly observed adverse effects of cyclosporin A (CsA) is the development of gingival overgrowth (GO). Fibroblasts are involved in GO, but the question why only a percentage of patients undergoing CsA treatment shows this side-effect remains unanswered. In a previous study, CsA has been demonstrated to induce over-expression of phospholipase C (PLC) beta(1) in fibroblasts of patients with clinical GO, in cells from both enlarged and clinically healthy gingival sites. In this work, we assessed the expression of PLCbeta isoforms to investigate whether the exaggerated fibroblast response to CsA related to increased PLCbeta(1) expression could also be detected in CsA-treated patients without clinical signs of GO. Our results support the hypothesis of a multi-factorial origin of gingival overgrowth, including specific changes within the gingival tissues orchestrating fibroblastic hyper-responsiveness as a consequence of a long-term in vivo exposure to cyclosporin A.

Immunohistochemical study of cyclosporin-induced gingival overgrowth in renal transplant recipients

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSION

Leukocyte activation antigens play an important role in CsA-induced gingival overgrowth.

Risk factors for gingival overgrowth in patients medicated with ciclosporin in the absence of calcium channel blockers

OBJECTIVES

This study investigates the effect of a range of potential risk factors on the severity of gingival overgrowth in transplant patients medicated with ciclosporin in the absence of any calcium channel blockers.

MATERIALS AND METHODS

One hundred dentate solid organ transplants medicated with ciclosporin (but not calcium channel blockers or phenytoin) were recruited for the study. Demographic, pharmacological and periodontal data were recorded and gingival overgrowth assessed from stone models.

RESULTS

Univariate analysis identified the duration of transplant, papilla bleeding index, creatinine serum concentration, azathioprine and prednisolone dosage as risk factors for overgrowth severity. Multivariate modelling, excluding the periodontal parameters, gave a predictive model that included dosages of ciclosporin, azathioprine, prednisolone and weight (p<0.0001, adjusted-R2=19%). Adding the periodontal variables strengthened the model (p<0.0001, adjusted-R2=34.5%).

CONCLUSION

The explanatory models in this study contain a number of variables that moderate inflammation (azathioprine and prednisolone) or are markers of it (papilla bleeding index). Dosage of each of the three immunosuppressants was identified as a risk factor for the severity of gingival change. This observation appears to have been masked by the effects of the calcium channel blockers in earlier studies.

Relationship between calcineurin inhibition and plasma endothelin concentrations in cyclosporine-A-treated kidney transplant patients

OBJECTIVE

The inter-individual variability of cyclosporine (CsA) pharmacokinetics is well known. However, there is obviously also an inter-individual pharmacodynamic variability, which might be explored by the measurement of biomarkers of CsA effects.

METHODS

In 11 renal transplant patients, blood CsA concentrations, calcineurin inhibition in peripheral blood mononuclear cells and endothelin plasma concentrations were measured over a 4-h period after CsA intake.

RESULTS

Mean plasma endothelin concentrations were higher than those of healthy subjects (3.66+/-0.46 pg ml(-1) versus 3.15+/-0.40 pg ml(-1), P<0.01) but were not related to CsA dose or blood concentrations. There was a linear relationship between calcineurin inhibition at t (0) and mean endothelin concentrations (r (2)=0.51, P<0.05). Patients with gingival hypertrophy had higher mean endothelin concentrations than patients without this complication (4.0 pg ml(-1) versus 3.4 pg ml(-1), P<0.01), although CsA doses and concentrations were not different between these two groups.

CONCLUSION

We observed a correlation between calcineurin inhibition and endothelin concentrations. Endothelin plasma concentrations is a biomarker of CsA effect, which may provide more information than CsA blood concentrations.

Cyclosporin A-induced gingival overgrowth in renal transplant patients

BACKGROUND

The incidence of gingival overgrowth (GO) associated with the use of cyclosporin A (CsA) is controversial. In the present study, we determined the incidence of GO in Brazilian renal transplant patients treated with CsA and the possible associations between periodontal and pharmacological variables.

METHODS

The test group consisted of 20 renal transplant patients, and the control group included 20 non-transplant patients. Periodontal conditions were evaluated based on the plaque index (PI), gingival index (GI), probing depth (PD), and the rate of gingival overgrowth, together with pharmacological variables (daily CsA dose and duration of treatment).

RESULTS

A significant difference in PI (P < 0.0001) and PD (P < 0.0001) was observed between groups, while GI (P = 0.15) did not differ significantly. Using the Pearson correlation coefficient, a significant correlation was observed not only between GI (P < 0.001; r = 0.8141) and GO, but also for PD (P < 0.001; r = 0.866) and GO. The other correlations were not statistically significant.

CONCLUSIONS

We conclude that GO induced by CsA may vary according to the individual sensitivity of each patient and may or may not be correlated with other local factors (periodontal variables).

Immunohistochemical analysis of lymphocyte subpopulations in cyclosporin A-induced gingival overgrowth

BACKGROUND

Cyclosporin A (CsA) is an immunosuppressive agent that is known to induce gingival overgrowth (GO). Pharmacological, genetic, immunologic, and inflammatory factors seem to be involved in the complex pathogenesis of drug-induced GO. Lymphocyte subpopulations in human gingival connective tissue have been implicated in the pathogenesis of inflammatory periodontal diseases. One purpose of this study was to quantify CD4, CD8-, CD57-, and epithelial membrane antigen (EMA)-positive cells in the gingiva of renal transplant recipients treated with CsA, and compare them to findings in healthy controls. A second aim was to correlate cell numbers with clinical findings.

METHODS

The study included 19 kidney recipients who were taking CsA and had significant GO (CsAGO+), 13 recipients who were taking CsA but showed no GO (CsAGO-), and 14 systemically healthy individuals with gingivitis (C). Sections from gingival biopsies were incubated with monoclonal antibodies for CD4, CD8, EMA, and CD57, and then analyzed using the avidin-biotin complex method. In each specimen, the mononuclear cell types were quantified and their distribution was evaluated in 3 separate tissue zones: S = subepithelial connective tissue beneath the sulcular epithelium; O = subepithelial connective tissue beneath the oral epithelium; and M = middle connective tissue.

RESULTS

There were no significant differences among the groups with respect to the numbers of CD4+ and CD8+ cells in each of the 3 zones (P >0.05). In zone S, the CsAGO+ group had significantly more EMA-positive cells than either the C or CsAGO- groups (P <0.05). There were significant differences among the groups regarding numbers of CD57+ (natural killer) cells in zone M, with the lowest cell numbers in the CsAGO+ patients (P<0.05).

CONCLUSIONS

The results showed that low numbers of natural killer cells are important in the expression of plaque-induced inflammatory changes in CsA-associated GO. It appears that these cells may influence the drug's ability to induce proliferative activity.

Macrophages and lymphocyte subpopulations in nifedipine- and cyclosporin A-associated human gingival overgrowth

BACKGROUND

Nifedipine and cyclosporin A (CsA) induce gingival overgrowth. Both drugs have immunomodulating effects. It has been suggested that altered immune response is associated with drug-induced gingival overgrowth. In this study, we evaluated whether there were differences in macrophages and lymphocyte subpopulations in human nifedipine- and CsA-associated gingival overgrowth as compared with those in normal gingiva.

METHODS

Biopsy samples of overgrown gingiva were obtained from 9 nifedipine-treated cardiac outpatients, 13 CsA-treated renal transplant recipients including 9 patients who were also receiving nifedipine, and 30 healthy control individuals undergoing dental treatment. Serial 5 microm thick cryostat sections were stained with mAbs for CD20 (B-pan), CD68 (macrophages), CD4 (T-helper/inducer), and CD8 (T-cytotoxic/suppressor) using an avidin-biotin-horseradish peroxidase complex method. Numbers of mAb-labeled and all nucleated cells were determined in 3 areas: the connective tissue beneath the sulcular epithelium, the middle connective tissue, and the connective tissue beneath the oral epithelium. Distributions of each type of cell were expressed as percentages of mAb-labeled cells in relation to total number of nucleated cells in a counting zone. Significances of differences between groups were tested by means of the Kruskal-Wallis test, and between pairs of results by means of the Mann-Whitney U-test.

RESULTS

The proportion of CD8-labeled cells was significantly higher in connective tissue beneath the sulcular epithelium in the nifedipine group than in the controls (P = 0.014). In both medicated groups, the proportions of CD68-labeled cells were higher in all counting zones than in the controls, but statistically significantly only in the nifedipine group in the connective tissue beneath the oral epithelium (P = 0.008). No intergroup differences were found with respect to CD4- and CD20-labeled cells. The CD4/CD8 ratio was significantly lower in connective tissue beneath the sulcular epithelium in the nifedipine group than in the controls (P= 0.013).

CONCLUSION

The results support the idea that immune response may be altered in drug-induced gingival overgrowth.

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.

Photographic scoring of gingival overgrowth

BACKGROUND

A wide range of methods have been employed to determine the severity of gingival overgrowth resulting in uncertainty regarding the prevalence of the side-effect. There is no simple, non-invasive, objective, blind method for assessing gingival overgrowth.

AIM

This article aims to describe a method which is suitable for use in large-scale population studies.

MATERIALS AND METHODS

Photographs were taken of the anterior, buccal gingivae and teeth of 925 patients medicated with calcium channel blockers. In addition, each patient was ascribed a clinical gingival overgrowth score. 100 patients had repeat photographs, and a further 10 patients had alginate impressions taken. The models were scored for severity of gingival overgrowth using a described technique. The slides were scored using a modification of this technique.

RESULTS

When photographic and study model scores were compared, photographic scores were consistently higher, and as a result, a photographic score of 38.6% was considered to represent a significant overgrowth. There was good agreement between clinically determined scores and photographic scores (kappa=0.71).

CONCLUSIONS

The results indicate that this method is suitable for large-scale population studies where it also has the advantage of providing a continuous scale of gingival changes for subsequent statistical analysis.

Cyclosporin A upregulates phospholipase C beta1 in fibroblasts from gingival overgrowth

BACKGROUND

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.

METHODS

PLC beta1 was assessed by immunoblotting and immunocytochemistry means.

RESULTS

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.

CONCLUSIONS

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.

Phenytoin and cyclosporin A suppress the expression of MMP-1, TIMP-1, and cathepsin L, but not cathepsin B in cultured gingival fibroblasts

BACKGROUND

Fibroblasts are known not only to synthesize and secrete extracellular matrix proteins, but also to degrade them for connective tissue remodeling. Drug-induced gingival overgrowth is characterized by a massive accumulation of extracellular matrix components in gingival connective tissues. Although some previous reports suggested that causative drugs stimulated the fibroblast proliferation, the results are not conclusive yet. In this study, we hypothesized that drug-induced gingival overgrowth could be a consequence of impaired ability of matrix degradation rather than an enhanced proliferation of gingival fibroblasts induced by these drugs.

METHODS

Normal human gingival fibroblasts were cultured with or without either 20 microg/ml of phenytoin or 200 ng/ml of cyclosporin A. Total RNA and cellular proteins were collected every day for RT-PCR analyses and for measuring lysosomal enzyme activity. In addition, an immunohistochemical study was performed to detect lysosomal enzymes in cells from enlarged gingiva of the patients with phenytoin-induced gingival overgrowth.

RESULTS

RT-PCR analyses revealed that these drugs suppressed the expression of MMP-1, TIMP-1, and cathepsin L, but not that of cathepsin B in a time-dependent manner. Then, we measured the activity of lysosomal enzymes and cathepsin B and L. The results indicated that although cathepsin B activity was not observed to be impaired, regardless of the drugs used in these cells, both total and active forms of combined activity of cathepsins B and L were suppressed in a time-dependent manner.

CONCLUSIONS

The results indicate that, besides suggested effects of these drugs on gingival fibroblasts and/or on accumulated cells in the gingival tissues, extracellular matrix-degrading ability, particularly that by cathepsin L, is also suppressed by cyclosporin A and phenytoin in gingival fibroblasts, and that lysosomal enzyme plays an important role in the pathogenesis of drug-induced gingival hyperplasia.

Risk factors in the development of cyclosporine-induced gingival overgrowth

BACKGROUND

Severe gingival hyperplasia (GH) is one of the most frequent side-effects associated with the prescription of cyclosporine-A (CsA). Using the largest group of renal allograft recipients assembled for this purpose, in this study, we statistically modeled the genetic (HLA), medical, and dental risk factors for the development of GH subsequent to administration of CsA.

METHODS

Two hundred thirty-six renal transplant patients underwent full dental examination to quantify the extent and distribution of hyperplasia and dental disease (gingivitis, plaque, and calculus). Computerized data from all patients included pre-transplant medical history and dosage of nifedipine and azathioprine, as well as dose and serum levels of CsA and CsA microemulsion. Donor and host HLA haplotype were studied to investigate potential association of haplotype and donor-host mismatching with the development of GH. We evaluated the data by multivariate regression analysis, using Statistical Package for Social Sciences (SPSS).

RESULTS

There was no association with age, sex, duration of renal replacement therapy, or interval since transplantation or pre-transplant disease (P>0.05). There also was no association of disease with host HLA haplotype, but degree of HLA-A mismatching was protective for GH development (P<0.002). GH was associated with the dose and serum levels of CsA (P<0.001) and the last dose of CsA microemulsion (P=0.009) but not nifedipine (P=0.10). Gingival inflammation and plaque were also strongly associated with GH (P<0.0003). In multivariate analysis, however, the last recorded dose of CsA (P<0.0001), presence of local gingival inflammation (P<0.0001), and gingivitis (P<0.003) were the independent predictors of the extent and severity of GH.

CONCLUSIONS

Inter-patient variation in the extent and severity of GH is related to CsA dose and serum levels. Differences in host HLA phenotype do not explain individual susceptibility to GH, but donor-host HLA-A mismatching may be important. Inter-site variation in the extent and severity of the disease is related to local gingival inflammation.

Levels of leukotriene B4 and platelet activating factor in gingival crevicular fluid in renal transplant patients receiving cyclosporine A

BACKGROUND

Cyclosporine A (CsA) is a potent immunosuppressant effectively used to prevent organ transplant rejection and also to treat several systemic diseases. CsA-induced gingival overgrowth (CsA GO) is the most widely seen side effect of this drug; its pathogenesis is not completely understood. The aim of the present study was to identify the role of leukotriene B4 (LTB4) and platelet activating factor (PAF) in the pathogenesis of CsA GO.

METHODS

LTB4 and PAF levels were detected in gingival crevicular fluid (GCF) samples from renal transplant patients receiving CsA therapy and exhibiting CsA GO, from patients with gingivitis and from periodontally healthy subjects. Plaque index, papilla bleeding index, and hyperplastic index were recorded at each study site. GCF samples and clinical data were obtained from: 2 sites exhibiting CsA GO (CsA GO+) and 2 sites not exhibiting CsA GO (CsA GO-) in each CsA-treated patient; 2 diseased sites in each patient with gingivitis; and 2 healthy sites in each subject with clinically healthy periodontium. LTB4 was extracted from the samples by solid-phase method using C18 cartridge and purified by high-performance liquid chromatographic (HPLC) method and analyzed by radioimmunoassay (RIA). PAF was extracted from GCF samples passing through amberlit resin columns, purified by HPLC, and analyzed by RIA.

RESULTS

Total amounts of LTB4 and PAF in GCF were higher in CsA GO+ sites compared to the healthy sites from healthy controls. However, the amount of LTB4 and PAF elevation in CsA GO+ sites was not significantly higher than those in diseased sites. Clinical degrees of gingival inflammation were also similar between CsA GO+ and diseased sites. LTB4 and PAF total amounts in GCF were higher in CsA GO+ sites compared to CsA GO- sites in the same subjects, but this difference just failed to reach significance. Similar findings were obtained with concentration data.

CONCLUSIONS

The results of this study indicate that CsA therapy does not have a significant effect on GCF LTB4 and PAF levels and that gingival inflammation seems to be the main reason for their elevation. In CsA-treated patients, alterations in LTB4 and PAF levels might play a role in CsA GO through some asyet unknown mechanism. To our knowledge, this is the first report describing the levels of lipid mediators in GCF of CsA-treated patients. We assume that further studies will contribute to the understanding of the pathogenesis of CsA-induced gingival overgrowth.

The gingival plasma cell infiltrate in renal transplant patients on an immunosuppressive regimen

Treatment with immunosuppressive agents inhibits gingival inflammation and progression of periodontitis in humans. We examined the numbers and the isotype distribution of immunoglobulin-producing plasma cells by immunohistochemistry in gingival specimens taken from renal transplant transplant recipients receiving immunosuppressive agents (IS), and from otherwise comparable systemically healthy patients. The immunosuppressed patient group had significantly (P< 0.05) fewer IgG-, IgA-, IgG1-, IgG2-, and IgG4-producing plasma cells in the connective tissue adjacent to the pocket epithelium. The reduced numbers of such patents with quiescent periodontal disease support the contention that high counts of plasma cells are indicative of more severe disease.

Medication induced gingival overgrowth

A number of idiopathic, pathological and pharmacological reactions may result in an overgrowth of the gingiva. This review concentrates on those overgrowths associated with various pharmacological agents. The pharmaco-kinetics and side effects of each drug associated with gingival overgrowth are discussed along with the clinical and histological features and treatment. By examining the possible pathogeneses for these overgrowths we propose a unifying hypothesis for the causation based around inhibition of apoptosis and decreased collagenase activity modulated by cytoplasmic calcium.

The clinical effects of nifedipine on periodontal status

The present study was conducted to determine the clinical effects of nifedipine on the gingiva of 97 patients. Patients were examined for changes in periodontal status and divided into subgroups, based on their age, gender, duration of drug intake, presence/absence of plaque and gingival inflammation, and according to the presence and severity of gingival overgrowth. Gingival overgrowth was noticed in 29% of the patients. Among the recorded parameters, duration of drug intake, presence/severity of gingival inflammation, and gender seemed to have the greatest effect on the development of gingival overgrowth. Patients with higher gingival inflammation scores, those on nifedipine medication for more than 4 years, and males were likely to have an increased tendency for higher incidence and severity of gingival overgrowth. The findings of the present study suggest that nifedipine medication induces gingival overgrowth and that certain local factors are involved in the pathogenesis of drug-induced gingival overgrowth. However, individual ability and sensitivity to metabolize the drug and its metabolites also seem to be important etiological factors.

Histopathologic alterations of periodontium in cyclosporin-treated rats. Is the periodontium a target tissue for the drug?

Gingival dimensions and histopathologic alterations in periodontium were examined in rats continuously exposed to cyclosporin-A (CSA). 60 male Sprague-Dawley rats were divided into 2 groups. Rats in the test group daily received CSA in mineral oil by gastric feeding at a dosage of 30 mg/kg body weight for 6 weeks. Rats in the control group received mineral oil only. 10 rats from each group were sacrificed at 2-week intervals. Gingival dimensions were assessed from stone models obtained from the maxillary and mandibular incisal regions. Horizontal, sagittal and frontal tissue sections were obtained from these regions as well. Gingival dimensions in the mandibular and maxillary incisal regions were significantly increased in rats exposed to CSA. Light-microscopic observations revealed a granulation tissue formation at tooth-gingiva interface and an irregular bony surface on dental alveoli in experimental animals. Because both soft and hard tissue of periodontium in experimental rats being significantly effected by CSA compared to control animals, we hypothesized that the periodontium is a target tissue for CSA.

The pathogenesis of drug-induced gingival overgrowth

Gingival overgrowth is a well-documented unwanted effect, associated with phenytoin, cyclosporin, and the calcium channel blockers. The pathogenesis of drug-induced gingival overgrowth is uncertain, and there appears to be no unifying hypothesis that links together the 3 commonly implicated drugs. In this review, we consider a multifactorial model which expands on the interaction between drug and/or metabolite, with the gingival fibroblasts. Factors which impact upon this model include age, genetic predisposition, pharmacokinetic variables, plaque-induced inflammatory and immunological changes and activation of growth factors. Of these, genetic factors which give rise to fibroblast heterogeneity, gingival inflammation, and pharmacokinetic variables appear to be significant in the expression of gingival overgrowth. A more thorough understanding of the pathogenesis of this unwanted effect will hopefully elucidate appropriate mechanisms for its control.

Gingival overgrowth induced by nifedipine and cyclosporin A. Clinical and morphometric study with image analysis

In this study, we developed a quantitative method with digital image analysis to evaluate the degree of gingival overgrowth (GO), and compared GO in kidney transplant patients treated with cyclosporin A (CsA) (n = 21) or CsA+nifedipine (n = 8) and a group of healthy controls (n = 30). The method was reproducible and reliable. Our findings showed significant differences in papillary and gingival surface between controls and transplant patients treated with GO inducers. Gingival overgrowth index also differed significantly between controls and each patient group (p < 0.01, Kruskal-Wallis test). The administration of the calcium channel blocker nifedipine potentiated the adverse effect of CsA: comparison of the morphometric findings revealed significant differences between patients treated with CsA alone and CsA+nifedipine in papillary area, dental area, and GO index (p < 0.01, Mann-Whitney U-test). We conclude that the method of image analysis we developed is useful in assessing the degree of GO.