Upregulation of Transforming Growth Factor-β1 and Vascular Endothelial Growth Factor Gene and Protein Expression in Cyclosporin-Induced Overgrown Edentulous Gingiva in Rats

Refining the Mechanism of Drug-Influenced Gingival Enlargement and Its Management

Drug-influenced gingival enlargement (DIGE) or overgrowth manifests as abnormal enlargement of the gingiva due to an adverse effect of certain drug reactions in patients treated with anticonvulsants, immunosuppressants, or calcium channel blockers (CCBs). As the gingival enlargement became significant, it may interfere with the normal oral hygiene measures, aesthetics, as well as masticatory functions of the patients. The exact mechanism of how this undesirable condition develops is yet unknown, and complicated, with non-inflammatory and inflammatory pathways involved. This review illuminates these putative pathways of DIGE and highlights various treatment approaches based on existing research and current observations.

Transcriptional Analysis Reveals Key Genes in the Pathogenesis of Nifedipine-Induced Gingival Overgrowth

Background

Nifedipine-induced gingival overgrowth (NGO) is a multifactorial pathogenesis with increased extracellular matrix including collagen and glycans, inflammatory cytokines, and phenotype changes of fibroblasts. However, the molecular etiology of NGO is not well understood. The objective of this study is to investigate the key genes in the pathogenesis of NGO.

Methods

In this study, we examined the proliferation and migration abilities of fibroblasts derived from patients with chronic periodontitis, nifedipine nonresponder gingival overgrowth, gingival overgrowth caused by nifedipine, and healthy normal gingiva. We conducted RNA-Seq on these four groups of fibroblasts and analysed the differentially expressed genes (DEGs).

Results

Fibroblasts derived from NGO patients had higher proliferation and migration abilities than those of the other groups. Protein-protein interaction network analysis indicated that TGFB2, ITGA8, ITGA11, FGF5, PLA2G4D, PLA2G2F, PTGS1, CSF1, LPAR1, CCL3, and NKX3-1 are involved in the development of NGO. These factors are related to the arachidonic acid metabolism and PI3K/AKT signaling pathways.

Conclusion

Transcriptional gene expression analysis identified a number of DEGs that might be functionally related to gingival overgrowth induced by nifedipine. Our study provides important information on the molecular mechanism underlying nifedipine-induced gingival overgrowth.

Pterostilbene prevents LPS-induced early pulmonary fibrosis by suppressing oxidative stress, inflammation and apoptosis in vivo

Early pulmonary fibrosis after acute lung injury leads to poor prognosis and high mortality. Pterostilbene (Pts), a bioactive component in blueberries, possesses anti-inflammatory, antioxidative and antifibrotic properties. However, the effects of Pts on lipopolysaccharide (LPS)-induced pulmonary fibrosis are still unknown. In our study, the Pts group showed lower lung injury and fibrosis scores, and lower levels of hydroxyproline and protein (collagen I and transforming growth factor-β) than the scores and levels in mice treated with LPS. MMP-1 was the degrading enzyme of collagen I and LPS caused the inhibition of MMP-1, disturbing the degradation of collagen. Additionally, Pts remarkably reversed the LPS-induced inhibition of interleukin-10 and the release of tumor necrosis factor-α, interleukin-6 and interleukin-1β. In terms of cellular pathways, Pts treatment ameliorated LPS-activated nuclear factor kappa B (NF-κB) and NOD-like receptor NLRP3 signaling. Besides, LPS-induced low levels of A20 could be activated by Pts. In addition, Pts treatment reversed the high levels of Caspase-3, poly ADP-ribose polymerase (PARP) and Bcl2-associated X protein (Bax) expression and the low levels of B cell lymphoma/lewkmia-2 (Bcl2) that had been induced by LPS. Moreover, oxidative stress is also involved in the pathogenesis of fibrosis. Our findings indicate that LPS injection triggered the production of myeloperoxidase (MPO) and malondialdehyde (MDA) and the depletion of superoxide dismutase (SOD) and glutathione (GSH), and that these effects were notably reversed by treatment with Pts. In addition, Pts induced the dissociation of Kelch-like epichlorohydrin-associated protein-1 (Keap-1) and NF-E2 related factor-2 (Nrf2) and the activation of downstream genes (heme oxygenase-1, NAD(P)H:quinine oxidoreductase, glutamate-cysteine ligase catalytic subunit and glutamate-cysteine ligase modifier). In conclusion, oxidative stress, apoptosis and inflammation are involved in early pulmonary fibrosis and Pts exerts a protective effect by activating Keap-1/Nrf2, inhibiting caspase-dependent A20/NF-κB and NLRP3 signaling pathways.

Lack of Association Between TGF-β1 and MDR1 Genetic Polymorphisms and Cyclosporine-Induced Gingival Overgrowth in Kidney Transplant Recipients: A Meta-analysis

BACKGROUND

Gingival overgrowth (GO) induced by cyclosporine (CsA), one of the common complications after kidney transplantation, is associated with a genetic component. However, the effect of TGF-β1 and MDR1 gene polymorphisms on the pathogenesis of CsA-induced GO remains to be determined. This study aimed to determine the association between TGF-β1 and MDR1 gene polymorphisms and CsA-induced GO in kidney transplant recipients.

METHODS

The Pubmed, Embase, Cochrane Library, and Chinese CNKI (China National Knowledge Infrastructure) and Wanfang databases were comprehensively searched. Data were extracted and pooled results estimated from odds ratios (ORs) and 95% confidence intervals (CIs). In addition, quality assessment and publication bias of each eligible study were examined.

RESULTS

Three trials focusing on the relationship between TGF-β1 +869T>C and +915G>C and 3 studies on MDR1 C3435T gene polymorphisms and the onset of CsA-induced GO were included. No association between the +869T>C polymorphism and CsA-induced GO was found in the dominant model (TT+TC vs CC: OR, 0.77; 95% CI, 0.29-2.10; P = .614). In the recessive model, no association was found between the +915G>C polymorphism and CsA-induced GO (CC vs GG+GC: OR, 1.40; 95% CI, 0.81-2.43; P = .225). And in the dominant model, no significance was calculated between MDR1 C3435T gene polymorphisms and CsA-induced GO in kidney transplant recipients (TT vs CC+CT: OR, 1.14; 95% CI, 0.62-2.09; P = .68).

CONCLUSIONS

No significant association exists between TGF-β1 +869T>C, and +915G>C and MDR1 C3435T gene polymorphisms and the pathogenesis of CsA-induced GO in kidney transplant recipients.

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.

Epithelial to mesenchymal transition in Cyclosporine A-induced rat gingival overgrowth

BACKGROUND AND OBJECTIVE

Epithelial-mesenchymal transition (EMT) has been proved to occur in drug-induced gingival overgrowth. However, the specific pathogenic mechanism remains uncertain. The aim of this study is to examine the expression of EMT markers in cyclosporine A (CsA)-induced gingival overgrowth in rat models.

MATERIAL AND METHODS

Thirty-six rats were randomly divided into two groups. The experimental group received CsA therapy subcutaneously in a daily dose of 10mg/kg, and the other group was used as a control. Six rats per group were sacrificed at 20, 40 and 60days, and the gingivae were obtained. The expression of TGF-β1, E-Cadherin, ZEB1, ZEB2, and Snail1 were examined by quantitative real time PCR (qRT-PCR), western blotting, and immunohistochemistry. In addition, a group of microRNAs associated with EMT and fibrosis were also detected in gingival tissue by qRT-PCR.

RESULTS

The mRNA and protein levels of TGF-β1, ZEB1, and ZEB2 in gingivae were significantly upregulated after 40 and 60days of CsA administration. Conversely, the levels of E-cadherin were significantly downregulated in overgrowth sample at day 40 and 60. Intense immunohistochemmical staining for TGF-β1 were observed in the samples from CsA group at day 40 and 60. Concomitantly, the densities of E-cadherin were gradually decreased in the basal layers of epithelium with time. Three members of miR-200s (miR-200a, miR-200b and miR-200c) were significantly downregulated in CsA-treated rats at 40 and 60days, while miR-9, miR-23a and miR-155 were significantly upregulated when compared with those of the control group.

CONCLUSIONS

The process of EMT in CsA-induced rat gingival overgrowth is associated with increased expression of TGF-β1, ZEB1, and ZEB2, and decreased expression of E-cadherin.

Role of transforming growth factor-beta1 in cyclosporine-induced epithelial-to-mesenchymal transition in gingival epithelium

BACKGROUND

It has been proposed that cyclosporin A (CsA) may induce epithelial-to-mesenchymal transition (EMT) in gingiva. The aims of the present study are to confirm the notion that EMT occurs in human gingival epithelial (hGE) cells after CsA treatment and to investigate the role of transforming growth factor beta1 (TGF-β1) on this CsA-induced EMT.

METHODS

The effects of CsA, with and without TGF-β1 inhibitor, on the morphologic changes of primary culture of hGE cells were examined in vitro. The changes of protein and messenger RNA (mRNA) expressions of two EMT markers (E-cadherin and alpha-smooth muscle actin) in the hGE cells after CsA treatment with and without TGF-β1 inhibitor were evaluated with immunocytochemistry and real-time polymerase chain reaction.

RESULTS

The epithelial cells became spindle-like, elongated, and disassociated from neighboring cells and lost their original cobblestone monolayer pattern when CsA was added. However, the epithelial cells stayed in their original cobblestone morphology with treatment of TGF-β1 inhibitor on top of the CsA treatment. When CsA was given, the protein and mRNA expressions of E-cadherin and α-SMA were significantly altered, and these alterations were significantly reversed with pretreatment of TGF-β1 inhibitor.

CONCLUSIONS

CsA could induce Type 2 EMT in gingiva by changing the morphology of epithelial cells and altering the EMT markers/effectors. The CsA-induced gingival EMT is dependent or at least partially dependent on TGF-β1.

Role of Shh and TGF in cyclosporine-enhanced expression of collagen and α-SMA by gingival fibroblast

OBJECTIVE

Cyclosporine-A (CsA)-induced gingival overgrowth may arise from an alteration in stoma matrix homeostasis. Sonic hedgehog (Shh) plays a key role during embryogenic development and fibrotic progression, and may be involved in CsA-altered gingival matrix homeostasis.

METHODS

Using the reverse transcription-polymerase chain reaction and Western blot analysis, we investigated the mRNA and protein expressions of Shh, type 1 collagen (COL1), alpha-smooth muscle actin (α-SMA) and transforming growth factor-beta (TGF-β) in human gingival fibroblasts after CsA treatments. The effect of Shh on CsA-induced alterations was further evaluated by the extra-supplement or inhibition of Shh or TGF-β.

RESULTS

Cyclosporine-A enhanced COL1, α-SMA, Shh and TGF-β expressions in human gingival fibroblasts. The exogenous Shh/TGF-β augmented the expression of COL1 and α-SMA, and the Shh/TGF-β inhibition suppressed the CsA-enhanced COL1 and α-SMA expressions. Moreover, Shh mRNA and protein expressions increased if extra-supplementing the exogenous TGF-β, whereas the CsA-upregulated Shh was mitigated by the TGF-β pathway inhibitor. However, neither exogenous Shh nor the Shh pathway inhibitor alters TGF-β expression or CsA-up-regulated TGF-β expression.

CONCLUSIONS

Shh, regulated by TGF-β, mediates CsA-altered gingival matrix homeostasis.

Cyclosporine A up-regulates Sonic hedgehog in gingiva: role of the up-regulation on gingival cell proliferation

BACKGROUND AND OBJECTIVE

Sonic hedgehog protein (SHH) is a mitogen that stimulates cell proliferation. Cyclosporine A enhances the proliferation of gingival cells; however, the relationships of SHH to cyclosporine A or to cyclosporine A-enhanced gingival cell proliferation have not been described.

MATERIAL AND METHODS

Here, we investigated SHH expression in gingiva in vitro and in vivo after cyclosporine A treatment and tested the effect of SHH inhibition on cyclosporine A-enhanced gingival fibroblast proliferation in vitro.

RESULTS

In human gingival fibroblasts, cyclosporine A treatment increased the expression of SHH transcripts and SHH protein, and stimulated cell proliferation; the addition of cyclopamine, an SHH signaling inhibitor, suppressed cyclosporine A-enhanced cell proliferation. Up-regulated expression of SHH and up-regulation of proliferating cell nuclear antigen transcripts and protein were observed in the edentulous gingiva of cyclosporine A-treated rats.

CONCLUSION

Cyclosporine A up-regulates gingival SHH expression in vitro and in vivo, and the inhibition of the SHH pathway counteracts the stimulatory effect of cyclosporine A on gingival fibroblast proliferation. Therefore, we suggest that SHH mediates a novel molecular mechanism for cyclosporine A-induced gingival complications.

Effect of adjunctive roxithromycin therapy on interleukin-1β, transforming growth factor-β1 and vascular endothelial growth factor in gingival crevicular fluid of cyclosporine A-treated patients with gingival overgrowth

BACKGROUND AND OBJECTIVE

Systemic macrolide antibiotic administration has been shown to result in the elimination or reduction cyclosporine A-induced gingival overgrowth. Roxithromycin (ROX) is known to have anti-inflammatory, immunomodulatory and tissue reparative effects. This study was to evaluate the effect of adjunctive ROX therapy on cyclosporine A-induced gingival overgrowth and interleukin (IL)-1β, transforming growth factor (TGF)-β1 and vascular endothelial growth factor (VEGF) levels in gingival crevicular fluid of renal transplant patients.

MATERIAL AND METHODS

Thirty-one patients with clinically significant overgrowth and 16 periodontally healthy subjects were included in this randomized, double-blind, placebo-controlled, parallel-arm study. Patients received scaling and root planing (SRP) at baseline and randomized to take either ROX or placebo for 5 d. The clinical parameters, including plaque index, papillary bleeding index, probing depth and gingival overgrowth scores, were recorded. The amounts of IL-1β, TGF-β1 and VEGF in gingival crevicular fluid were detected by ELISA. Periodontal parameters as well as gingival crevicular fluid biomarker levels were evaluated at baseline and at 1 and 4 wk post-therapy.

RESULTS

Following SRP plus ROX and SRP plus placebo therapy, significant improvements in clinical periodontal parameters of both study groups were observed (p < 0.025). In the ROX group, adjunctive ROX therapy resulted in a greater gingival overgrowth scores reduction compared with those in the placebo group at 4 wk (p < 0.017). Initial amounts of IL-1β, TGF-β1 and VEGF for both the ROX and placebo groups were significantly higher than those for healthy subjects (p < 0.017), with no statistical difference between the two study groups. At 1 and 4 wk post-therapy, significant decreases in the amounts of IL-1β, TGF-β1 and VEGF were observed in both study groups when compared with baseline (p < 0.025), but there was no difference in the levels of IL-1β and VEGF between the two study groups. The amount of decrease in TGF-β1 levels for the ROX group was statistically significant compared to that for the placebo group at 4 wk after treatment (p < 0.017).

CONCLUSION

Our study indicated that combination of ROX with non-surgical therapy improves gingival overgrowth status and decreases gingival crevicular fluid TGF-β1 levels in patients with severe gingival overgrowth. The reduction of gingival crevicular fluid TGF-β1 following ROX therapy suggests an anti-inflammatory/immunomodulatory effect of ROX on the treatment of cyclosporine A-induced gingival overgrowth.

Crosstalk between Shh and TGF-β signaling in cyclosporine-enhanced cell proliferation in human gingival fibroblasts

BACKGROUND

Immunosuppressant cyclosporine-A induces gingival hyperplasia, which is characterized by increased fibroblast proliferation and overproduction of extracellular matrix components and regulated by transforming growth factor-beta (TGF-β). The TGF-β and Sonic hedgehog (Shh) pathways both mediate cell proliferation. Crosstalk between these pathways in cancer has recently been proposed, but the hierarchical pattern of this crosstalk remains unclear. In normal fibroblasts, a TGF-β-stimulating Shh pattern was observed in induced fibrosis. However, Shh pathway involvement in cyclosporine-enhanced gingival proliferation and the existence of crosstalk with the TGF-β pathway remain unclear.

METHODOLOGY/PRINCIPAL FINDINGS

Cyclosporine enhanced mRNA and protein levels of TGF-β and Shh in human gingival fibroblasts (RT-PCR and western blotting). A TGF-β pathway inhibitor mitigated cyclosporine-enhanced cell proliferation and an Shh pathway inhibitor attenuated cyclosporine-enhanced proliferation in fibroblasts (MTS assay and/or RT-PCR of PCNA). Exogenous TGF-β increased Shh expression; however, exogenous Shh did not alter TGF-β expression. The TGF-β pathway inhibitor mitigated cyclosporine-upregulated Shh expression, but the Shh pathway inhibitor did not alter cyclosporine-upregulated TGF-β expression.

CONCLUSIONS/SIGNIFICANCE

The TGF-β and Shh pathways mediate cyclosporine-enhanced gingival fibroblast proliferation. Exogenous TGF-β increased Shh expression, and inhibition of TGF-β signaling abrogated the cyclosporine-induced upregulation of Shh expression; however, TGF-β expression appeared unchanged by enhanced or inhibited Shh signaling. This is the first study demonstrating the role of Shh in cyclosporine-enhanced gingival cell proliferation; moreover, it defines a hierarchical crosstalk pattern in which TGF-β regulates Shh in gingival fibroblasts. Understanding the regulation of cyclosporine-related Shh and TGF-β signaling and crosstalk in gingival overgrowth will clarify the mechanism of cyclosporine-induced gingival enlargement and help develop targeted therapeutics for blocking these pathways, which can be applied in pre-clinical and clinical settings.

Effect of cyclosporine-A on orthodontic tooth movement in rats

OBJECTIVE

The objective of this study is to examine the effect of cyclosporine-A (CsA) on the rate of orthodontic tooth movement in rats.

SETTING AND SAMPLE POPULATION

This is a randomized controlled trial with a split-mouth design in Sprague-Dawley rats.

MATERIAL AND METHODS

Eighteen rats, divided at random in two groups, were fed with 8 mg/kg CsA (experiment) or mineral oil (control) daily after initial healing of bilateral maxillary second molar removal. All rats received orthodontic coil springs (10 cN) secured to the maxillary incisors and first molars at the rights side, while no springs were placed at the left. Distances between first and third molars were measured on days 0, 3, 6, and 12. After sacrificing on day 12, the alveolar ridges of the maxillae were sectioned and blood samples were collected for serum tartrate-resistant acid phosphatase (TRAP)-5b level detection and for histology, respectively.

RESULTS

Significantly larger changes in intermolar distances were found after orthodontic force application in the CsA group at days 3 and 12 when compared with the control group. The inter-radicular dental alveolus of CSA-fed rats was osteopenic. Significantly increased TRAP-5b serum level was noted in the CsA group when compared with the control group.

CONCLUSIONS

We suggest that CsA enhanced the rate of orthodontic tooth movement. The osteopenia and the increased osteoclastic activity could be the underlying factors.

Cyclosporine A inhibits the expression of membrane type-I matrix metalloproteinase in gingiva

BACKGROUND AND OBJECTIVE

Membrane type-I matrix metalloproteinase (MMP) and tissue inhibitor of metalloproteinase-2 (TIMP-2) regulate the activation of MMP-2; however, their roles in the activation of MMP-2 in gingiva during treatment with cyclosporine A are still unknown. Therefore, the expressions of membrane type-I MMP and TIMP-2, as well as MMP-2, in gingivae upon treatment with cyclosporine A were examined in vivo and in vitro.

MATERIAL AND METHODS

Thirty-four rats were divided into two groups after edentulous ridges were established. The experimental group received 30 mg/kg/d of cyclosporine A and the control group received vehicle. At the end of the experimental period, the rats were killed, the gingivae were obtained and the expression of mRNA and protein of membrane type-I MMP, TIMP-2 and MMP-2 in gingiva were examined using real-time polymerase chain reaction and immunohistochemistry. In human gingival fibroblasts, the activity of MMP-2 and the expression of MMP-2, membrane type-I MMP and TIMP-2 mRNAs were examined (using zymography and reverse transcription-polymerase chain reaction, respectively) after treatment with cyclosporine A.

RESULTS

In gingivae of rats, cyclosporine A significantly decreased the expression of mRNA and protein of membrane type-I MMP, but not of TIMP-2. The expression of MMP-2 mRNA was unaffected but the expression of MMP-2 protein showed a significant decrease upon treatment with cyclosporine A. In fibroblast culture medium, the presence of cyclosporine A induced a decrease in MMP-2 activity in a dose-dependent manner. The expression of MMP-2, membrane type-I MMP and TIMP-2 mRNAs in fibroblasts was not significantly affected by cyclosporine A; however, in fibroblasts the ratio of mRNA expression of membrane type-I MMP to that of TIMP-2 decreased as the cyclosporine A dose was increased.

CONCLUSION

Cyclosporine A inhibits the expression of membrane type-I MMP in gingiva and it may further reduce the activation of MMP-2.

Expression of p21 and p53 in rat gingival and human oral epithelial cells after cyclosporine A treatment

BACKGROUND AND OBJECTIVE

Expression of p21 and p53 were examined, at gene and protein levels, in edentulous gingival epithelial cells from rats and from a human oral epidermoid carcinoma cell line, OECM1, after cyclosporine A therapy.

MATERIAL AND METHODS

In vivo: 20 partially edentulous SD rats were assigned into cyclosporine A feeding and control groups. After the rats were killed, p21 and p53 in gingiva were evaluated by reverse transcription-polymerase chain reaction and immunohistochemistry. In vitro: after cyclosporine A treatment, p21 and p53 of OECM1 cells were evaluated by western blot and the luciferase assay. The distribution of OECM1 cells in each phase of the cell cycle was evaluated by flow cytometry.

RESULTS

The mRNA expression of p21 was significantly higher in the cyclosporine A group than in the control group. A greater number of positive anti-p21-stained cells were observed in the gingival epithelium of the cyclosporine A group than in the control group. Significantly higher levels of p21 protein and activity were observed in OECM1 cells after cyclosporine A treatment than in cells without treatment. A relative increase of cells in G0/G1 phases, and a decrease of cells in G2/M phases, were observed in OECM1 cells after cyclosporine A treatment.

CONCLUSION

In the present study, higher p21 mRNA and protein expressions were observed after cyclosporine A treatment. Thus, an up-regulation of p21 expression, via a p53-independent pathway, by cyclosporine A in gingival and oral epithelial cells was suggested.

Gingival crevicular fluid transforming growth factor-beta1 in cyclosporine and tacrolimus treated renal transplant patients without gingival overgrowth

BACKGROUND

Gingival crevicular fluid (GCF) levels of transforming growth factor-beta(1) (TGF-beta(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-beta(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-beta(1) levels the present study aimed to evaluate gingival crevicular fluid (GCF) TGF-beta(1) levels in renal transplant patients using CsA or Tac without GO.

METHODS

GCF TGF-beta(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-beta(1) levels were analysed by enzyme-linked immunosorbent assay.

RESULTS

Both CsA and Tac groups had significantly elevated GCF TGF-beta(1) total amount compared to gingivitis and healthy groups (p<0.008). GCF TGF-beta(1) total amount of CsA and Tac groups was similar (p>0.008). Gingivitis and healthy groups had also similar GCF TGF-beta(1) total amount (p>0.008).

CONCLUSIONS

Within the limits of the present data it is unlikely that TGF-beta(1) is an exclusive mediator of CsA- or Tac-induced GO. However, pathogenesis of GO is multifactorial and contribution of TGF-beta(1) to the interrelations between cytokines and growth factors with fibrogenic potential cannot be disregarded.

Cyclosporin-A inhibits the expression of cyclooxygenase-2 in gingiva

BACKGROUND AND OBJECTIVE

Various inflammatory mediators are involved in the development of cyclosporine A-induced gingival overgrowth. In this study, the gingival expression of cyclooxygenase-2 after cyclosporine A therapy was examined in vivo and in vitro.

MATERIAL AND METHODS

After edentulous ridges on maxilla were established, 21 Sprague-Dawley rats received cyclosporine A daily for 4 wk, and a further 21 rats received solvent. After the rats were killed, the expression of cyclooxygenase-2 mRNA, interleukin-1beta mRNA, tumor necrosis factor-alpha mRNA, and interleukin-6 mRNA was examined in the edentulous gingiva. The expression of cyclooxygenase-2 protein and the production of prostaglandin E2 were also evaluated.

RESULTS

In cultured human gingival fibroblasts and epithelial cells, the expression of cyclooxygenase-2 mRNA was measured after treatment with cyclosporine A. Significantly lower expression of cyclooxygenase-2 and interleukin-1beta mRNA, but higher interleukin-6 expression, were observed in gingiva from cyclosporine A-treated rats than in those from the control rats. Significantly less prostaglandin E2 production was observed in cyclosporine A-treated rats. Immunohistochemistry revealed that fewer gingival stromal cells were positively stained for cyclooxygenase-2 in cyclosporine A-treated rats. In cultured cells, significantly less cyclooxygenase-2 mRNA was detected after treatment with cyclosporine A.

CONCLUSION

The expression of cyclooxygenase-2 was lower in the plaque nonretentive gingivae and the in vitro gingival cells upon treatment with cyclosporine A. Thus, we propose that cyclosporine A inhibits the expression of gingival cyclooxygenase-2.

The Expression of Vascular Endothelial Growth Factor in a Rat Model at Destruction and Healing Stages of Periodontal Disease

BACKGROUND

The major role of vascular endothelial growth factor (VEGF), an angiogenic mediator, in promoting the progression or the healing of periodontal disease is still unclear. The aim of this study was to evaluate the VEGF expression in the destruction and healing stages of periodontal disease and to investigate the association between VEGF expression and vascularization with regard to the number and diameters of blood vessels.

METHODS

Thirty rats were distributed equally into two test groups and a control group. Experimental periodontal disease was induced in the test groups by silk ligatures, which were kept in position for 40 days. On the 40th day, ligatures were removed from the healing group, whereas ligatures were left in position in the destruction group. On the 60th day, rats were sacrificed; histomorphometric and biochemical analyses were carried out to determine the number and diameters of blood vessels and the assessment of VEGF concentration by enzyme-linked immunosorbent assay, respectively.

RESULTS

There was a statistically significant increase in the number of blood vessels in the healing group and in the diameters of blood vessels in the destruction group compared to the control group (P <0.001). In vivo VEGF expressions were highest in the healing group (P <0.001) and correlated significantly with the number of blood vessels (r(2) = 0.814; P = 0.001).

CONCLUSION

VEGF expression may be related more to the healing stage of periodontal disease than to the destruction stage of the lesion.