Gingival overgrowth in renal transplant recipients: a study concerning prevalence, severity, periodontal, and predisposing factors

On the Cellular and Molecular Mechanisms of Drug-Induced Gingival Overgrowth

Introduction:

Gingival overgrowth has been linked to multiple factors such as adverse drug effects, inflammation, neoplastic processes, and hereditary gingival fibromatosis. Drug-induced gingival overgrowth is a well-established adverse event. In early stages, this gingival enlargement is usually located in the area of the interdental papilla. Histologically, there is an increase in the different components of the extracellular matrix.

Objective:

The aim of this manuscript is to describe and analyze the different cellular and molecular agents involved in the pathogenesis of Drug-induced gingival overgrowth.

Method:

A literature search of the MEDLINE/PubMed database was conducted to identify the mechanisms involved in the process of drug-induced gingival overgrowth, with the assistance of a research librarian. We present several causal hypotheses and discuss the advances in the understanding of the mechanisms that trigger this gingival alteration.

Results:

In vitro studies have revealed phenotypic cellular changes in keratinocytes and fibroblasts and an increase of the extracellular matrix with collagen and glycosaminoglycans. Drug-induced gingival overgrowth confirms the key role of collagenase and integrins, membrane receptors present in the fibroblasts, due to their involvement in the catabolism of collagen. The three drug categories implicated: calcineuron inhibitors (immunosuppressant drugs), calcium channel blocking agents and anticonvulsant drugs appear to present a multifactorial pathogenesis with a common molecular action: the blockage of the cell membrane in the Ca2+/Na+ ion flow. The alteration of the uptake of cellular folic acid, which depends on the regulated channels of active cationic transport and on passive diffusion, results in a dysfunctional degradation of the connective tissue. Certain intermediate molecules such as cytokines and prostaglandins play a role in this pathological mechanism. The concomitant inflammatory factor encourages the appearance of fibroblasts, which leads to gingival fibrosis. Susceptibility to gingival overgrowth in some fibroblast subpopulations is due to phenotypic variability and genetic polymorphism, as shown by the increase in the synthesis of molecules related to the response of the gingival tissue to inducing drugs. The authors present a diagram depicting various mechanisms involved in the pathogenesis of drug-induced gingival overgrowth.

Conclusion:

Individual predisposition, tissue inflammation, and molecular changes in response to the inducing drug favor the clinical manifestation of gingival overgrowth.

Efficacy of azithromycin and metronidazole combined therapy on rats' gingival overgrowth induced by cyclosporine-A: An experimental animal study

AIMS

To evaluate the therapeutic efficacy of azithromycin (azm) and/or metronidazole (mtz) on the histopathological features of rats' gingival overgrowth (GO) induced by cyclosporine-A (CsA) in an animal model.

METHODS

Ninety male albino rats were divided randomly into six equal groups. The rats of group I received corn oil via gastric feeding for 7 weeks. Group II rats were administered CsA for the same period. Groups III, IV, and V rats received CsA for 6 weeks and simultaneously in the 7th week received a monotherapy of placebo gel, azm suspension, mtz gel, respectively. Group VI rats were handled as groups III, IV, and V and instead received a combined therapy of azm suspension, and mtz gel. Rats were euthanized at the end of the experiment and routine tissue processing was carried out. The obtained specimens were stained with H&E, TGF-β, MMP-1, and IL-6 antibodies.

RESULTS

One-way MANOVA test for TGF-β, MMP-1, and IL-6 revealed an overall significant difference between the different groups (P = 0.000). LSD post hoc test for multiple comparisons of TGF-β revealed nonsignificant difference between groups I and VI and between groups IV and V. Nonsignificant difference was found between groups II and III considering the amount of MMP-1 immune expression. In addition, nonsignificant difference was found between groups V and VI regarding the amount of immune expression for IL-6.

CONCLUSION

Combined therapy of azm suspension and mtz gel significantly improved the histopathological features of CsA-induced GO better than a monotherapy of azm suspension or mtz gel.

Gingival overgrowth in renal transplant subjects: a 44-month follow-up study

BACKGROUND

To assess changes in gingival status of renal transplant subjects under immunosuppressive regimens based on cyclosporine (CsA), tacrolimus (Tcr), and sirolimus (Sir).

METHODS

From a sample of 135 subjects (baseline examination [BE]), 89 without periodontal treatment, who maintained the immunosuppressive regimen based on the same main agent (CsA=23, Tcr=31, and Sir=35), were reexamined after 44 months (follow-up examination [FE]). Demographic, pharmacologic, and periodontal variables were collected and gingival overgrowth (GO) was assessed by visual examination.

RESULTS

In Tcr and CsA groups, although not significant, occurrence of GO decreased (CsA [BE=56.5% and FE=34.8%; P=0.063] and Tcr [BE=19.4% and FE=12.9%; P=0.500]). In addition, the severity of GO decreased significantly in CsA group (mean score BE=10.29 ± 7.70 and mean score FE=0.78 ± 1.38; P=0.003). In Sir group, GO decreased from 17.1% (BE) to 0.0% (FE) (P=not applicable). In total sample, GO was associated with papillary bleeding index (P=0.001) and concomitant use of calcium channel blockers (P=0.029); in CsA and Tcr groups, GO was associated with papillary bleeding index (P=0.029 and 0.033, respectively).

CONCLUSIONS

There was no incidence of GO, and a decrease in the occurrence and severity of GO was significant in total sample. This decrease can be attributed to changes in pharmacologic and periodontal variables over this period of time.

The impact of amlodipine on gingival enlargement after kidney transplantation

Abstract

Background: Although cyclosporine (CsA) and calcium channel blockers (CCBs) parallel to each other may provoke gingival enlargement (GE), there are few considerations about combined effects of CsA and CCBs on gingival tissues.

Objectives: This study aimed to determine prevalence of GE among renal transplant recipients and to compare its occurrence in patients who received only CsA and those who were on CsA and amlodipine.

Patients and Methods: We conducted a prospective randomized case-control trial including 213 renal transplant recipients between February 2010 and August 2010. They were randomly divided into two groups including control group (on continuous treatment with CsA alone; n = 112) and trial group (treated with combined CsA and amlodipine; n = 101). Buccal, lingual, and inter-proximal membranes at last 12 anterior teeth were assessed for GE and packet depth (PD) using Gingival Index of McGaw and others, and Packet Index of Turesky–Gilmore–Glickman, respectively.

Results: Marked GE was observed in 26 patients (25.7%) in trial group and only in 4 individuals (3.6%) in control group (P = 0.000). In logistic regression analysis, obese (OR = 3, P = 0.04), older (OR = 2.8, P = 0.03), and female (OR = 1.3, P = 0.03) recipients as well as who received high dose amlodipine (OR = 4.4, P = 0.000) were at risk for marked GE.

Conclusions: There is a strong correlation between GE, in particular marked GE, and combination therapy with CsA and amlodipine in transplant patients compared to those treated by CsA alone. We suggest CsA dose reduction may restrain this adverse effect.

Integrity of the oral tissues in patients with solid-organ transplants

The relationship between the use of immunosuppressants in solid-organ transplant patients and oral tissue abnormalities has been recognized. The objective of this study was to determine the state of oral tissue integrity in renal, heart, and liver transplant patients who are on continuous medical and dental control. Forty patients of both sexes were clinically evaluated at the Clinical Hospital of the University of Chile to identify pathologies of oral mucosa, gingival enlargement (GE), decayed, missing, filled teeth (DMFT) index, and salivary flow. The average age of the transplant subjects was 49.4 years, and the age range was 19 to 69 years. Most subjects maintained a good level of oral hygiene, and the rate mean of DMFT was 14.7. The degree of involvement of the oral mucosa and GE was low (10%). Unlike other studies, the frequency of oral mucosal diseases and GE was low despite the fact that these patients were immunosuppressed. Care and continuous monitoring seem to be of vital importance in maintaining the oral health of transplant patients.

Cyclosporine-induced gingival overgrowth correlates with NFAT-regulated gene expression: a pilot study

OBJECTIVE

To determine whether incidence and severity of cyclosporine A (CsA)-induced gingival overgrowth (GO) is related to expression nuclear factor of activated T cells-regulated genes (NFAT-regulated genes).

MATERIAL AND METHODS

Expression of NFAT-regulated genes was determined in 36 transplant patients medicated with CsA by real-time PCR before and 2 h after drug intake and residual NFAT activity was estimated as ratio of both measurements. Demographic, periodontal and pharmacologic parameters were recorded and GO assessed from models. Subjects were divided into two groups according to the degree of GO (responders: GO score≥10%). Groups were compared using parametric and non-parametric tests. The association of various CsA-specific and periodontal parameters on incidence and extent of GO were determined using regression analysis.

RESULTS

Responders had a more than twofold lower residual NFAT activity than non-responders (7.9% and 18.1%, respectively; p<0.001). Multiple regression analysis revealed gingival inflammation, salivary CsA concentration, and residual NFAT activity to be significant factors influencing the expression of GO. Seventy-seven percent of the variability of GO could be explained by these parameters.

CONCLUSIONS

This study showed that pharmacodynamic parameters such as residual NFAT activity may be promising prognostic indicators to identify patients with increased risk for GO.

Reduction in lipopolysaccharide-induced apoptosis of fibroblasts obtained from a patient with gingival overgrowth during nifedipine-treatment

OBJECTIVE

We have previously demonstrated that the mechanism of nifedipine (NIF)-induced gingival overgrowth is related to the observation that proliferation and cell cycle progression of gingival fibroblasts derived from NIF reactive patient (NIFr) are greater than those from NIF non-reactive patient (NIFn). Gingival overgrowth has also been reported to be a result of inhibited apoptosis of gingival fibroblasts. Apoptosis in fibroblasts is induced by lipopolysaccharide (LPS). Thus, we focused upon evaluating whether there is a difference in LPS-induced apoptosis between NIFn and NIFr.

METHODS

Both NIFn and NIFr were arrested in DMEM containing 0.5% FBS, stimulated by LPS, and assayed for apoptosis, cell cycle analysis, Western blotting, and caspase activity.

RESULTS

Compared to NIFn, the number of apoptotic cells was significantly decreased and the percentage of cells in S and G(2)/M phase was significantly increased in NIFr. The levels of Bax and cytochrome c proteins in NIFr were not up-regulated by LPS compared with NIFn. Both NIFn and NIFr displayed the following changes in protein expression: increased Bad, decreased Bcl-xL, and unchanged Bcl-2 and p53. Caspase-3 and -9 activities were significantly increased by LPS in NIFn but were unchanged in NIFr. Caspase-2 activity remained constant whilst caspase-8 activity significantly increased upon LPS treatment in both NIFn and NIFr.

CONCLUSION

Bad, Bax, cytochrome c, p53, and caspases-2, -3, -8, and -9 are pro-apoptotic proteins. Bcl-2 and Bcl-xL are anti-apoptotic proteins. Thus, the mechanism of NIF-induced gingival overgrowth might be related to decreased apoptosis in NIFr through a reduction of Bax, cytochrome c, and caspase-3 and -9.

Gingival overgrowth in subjects under immunosuppressive regimens based on cyclosporine, tacrolimus, or sirolimus

AIM

To assess the prevalence and variables associated with gingival overgrowth (GO) in renal transplant recipients medicated with cyclosporine (CsA), tacrolimus (Tcr), or sirolimus (Sir).

MATERIALS AND METHODS

One hundred and thirty-five eligible subjects were divided in CsA, Tcr, and Sir groups comprising 45 subjects each. GO was visually assessed and subjects were assigned as GO+ or GO- in a post hoc definition. Saliva samples were collected and the presence of periodontal pathogens was assessed through polymerase chain reaction. Variables of interest were compared between GO+ and GO- subjects through univariate and multivariate analysis.

RESULTS

Prevalence of GO was of 60.0% for CsA, 28.9% for Tcr, and 15.6% for Sir groups. Within the CsA group, GO was associated with papillary bleeding index (p=0.001); within the Tcr group, GO was associated with CsA previous use (p=0.013), and calcium channel blockers (CCB) use (p=0.003); within the Sir group, GO was associated with papillary bleeding index (p=0.018), and CCB use (p=0.020). A higher frequency of Tannerella forsythia was observed among GO+ subjects medicated with Tcr.

CONCLUSION

Pharmacological and periodontal variables were associated with GO in different immunosuppressive regimens. Integration between the medical and the dental team may be an important approach in the post-transplant maintenance routine.

Refinement of the GINGF3 locus for hereditary gingival fibromatosis

Hereditary gingival fibromatosis (HGF) is a rare, clinically variable disorder characterized by slowly progressive fibrous overgrowth of the gingiva. Four gene loci have been mapped for autosomal dominant non-syndromic HGF (adHGF). The molecular basis of adHGF remains largely unknown, with only a single SOS1 gene mutation identified so far at the gingival fibromatosis 1 (GINGF1) locus in one family. We identified an adHGF family with ten affected individuals in whom onset of gingival fibromatosis concurred with the eruption of the primary teeth. In order to identify the molecular basis in this family, we tested for linkage of the disease to known adHGF loci. A maximal multipoint logarithm of the odds score of 3.91 was obtained with marker D2S390 (theta = 0) at the GINGF3 locus on chromosome 2p23.3-p22.3, and linkage to other known loci was excluded. Sequencing two candidate genes, ALK and C2orf18, and a single nucleotide polymorphisms array analysis did not reveal a mutation or copy number variation in a patient from the family. We refined the GINGF3 locus to a 6.56-cM, 8.27-Mb region containing 112 known and hypothetical genes, and our data and a search of the literature suggest that GINGF3 is a major adHGF locus.