Immunosuppression and gingival overgrowth: gene and protein expression profiles of collagen turnover in FK506-treated human gingival fibroblasts

Nifedipine and Cyclosporin Affect Fibroblast Calcium and Gingiva

It has been stated that cyclosporin and nifedipine produce gingival overgrowth. However, the specific pathogenic mechanism remains uncertain. We used an experimental rat model to test the hypothesis that changes in collagen metabolism and numbers of gingival blood vessels are not mediated by intracellular calcium concentration (ratiometric Fura-2 AM measurement) in gingival fibroblasts. In the cyclosporin group, both width (364.2 ± 67.5 μm) and microvessel density (number of vessels/mm2, stained with anti-CD34 antibody) (41.6 ± 5.1) of gingiva were statistically different when compared with those in the control group (width = 184.3 ± 35.2 μm, microvessel density = 19.6 ± 2.4). The nifedipine group showed the highest content of collagen (proportion of total stroma occupied by collagen, stained with Picro-Mallory) (nifedipine group = 66.3 ± 9.4, cyclosporin group = 55.2 ± 7.9, control group = 30.1 ± 10.2). Freshly cultured fibroblasts from the cyclosporin group exhibited higher ratiometric values of fluorescence than did both the control and nifedipine groups (p = 0.03). Our results support the hypothesis that changes in gingival collagen metabolism are not mediated by calcium intracellular oscillations.

Tacrolimus abrogates TGF-β1-induced type I collagen production in normal human fibroblasts through suppressing p38MAPK signalling pathway: implications on treatment of chronic atopic dermatitis lesions

BACKGROUND

Atopic dermatitis (AD) is a commonly encountered inflammatory skin disease. Although acute lesions of acute AD are characterized by intense inflammation, the hallmarks of chronic AD lesions include lichenified fibrosis and thickening of the upper dermis. The increased expression of transforming growth factor beta 1 (TGF-β1), a well-known fibrogenic cytokine, is observed in chronic AD lesions. Tacrolimus (FK506) ointment has been reported to be effective for treating AD as well as some TGF-β1-induced fibrotic diseases.

OBJECTIVES

To evaluate the effect of tacrolimus on TGF-β1-stimulated cultured normal human dermal fibroblasts and explore the potential signalling pathways involved.

METHODS

Fibroblasts cultured from healthy adult human foreskins were treated with TGF-β1 with or without tacrolimus. The impact on cell viability and proliferation were assessed by [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) assay and BrdU incorporation assay respectively. Reverse transcription-polymerase chain reaction (RT-PCR), quantitative real-time PCR, enzyme-linked immunosorbent assay (ELISA) and western blotting were performed to evaluate the relevant expressions of mRNA or proteins in fibroblasts.

RESULTS

Our results revealed that the increased expressions of transforming growth factor-β receptor I (TGF-βRI) and TGF-βRII in TGF-β1-treated fibroblasts were suppressed by tacrolimus treatment. In addition, tacrolimus significantly inhibited fibroblast proliferation enhanced by TGF-β1. TGF-β1 increased type I collagen production, and this enhancing effect was suppressed by tacrolimus. The down-regulation of MMP-1 and up-regulation of TIMP-1 induced by TGF-β1 were reversed by tacrolimus. The increase in phosphorylated p38 mitogen-activated protein kinase (p38MAPK) expression stimulated by TGF-β1 was down-regulated by tacrolimus. Moreover, the fibroblasts treated with p38MAPK inhibitor significantly reduced type I collagen expression induced by TGF-β1.

CONCLUSIONS

The present results demonstrated that tacrolimus significantly inhibited physiological functions of fibroblasts enhanced by TGF-β1 in vitro. Clinically, we propose that topical tacrolimus may not only reduce AD recurrence but also ameliorate dermal fibrosis often seen in chronic AD lesions.

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.

GCF and serum myeloperoxidase and matrix metalloproteinase-13 levels in renal transplant patients

AIM

The rationale of this study was to address whether local or systemic changes reflect proteolytic (matrix metalloproteinase-13) or oxidative (myeloperoxidase) stress in renal transplant patients receiving cyclosporine-A (CsA) and having gingival overgrowth (GO), in patients receiving CsA therapy and having no GO and patients receiving tacrolimus therapy.

MATERIAL AND METHODS

Gingival crevicular fluid (GCF) samples were collected from sites with (GO+) and without GO (GO-) in CsA patients having GO; GO- sites in CsA patients having no GO; sites from tacrolimus, gingivitis and healthy subjects. GCF and serum myeloperoxidase (MPO) and matrix metalloproteinase-13 (MMP-13) levels were determined by ELISA.

RESULTS

GO+ sites in CsA patients having GO had elevated GCF MPO levels than those of CsA patients having no GO, tacrolimus and healthy subjects (p<0.005), but comparable to those of gingivitis. GCF MPO levels were higher in GO+ compared to GO- sites in CsA patients having GO (p<0.05). Patient groups had similar, but higher GCF MMP-13 levels than healthy group.

CONCLUSIONS

These results show that CsA and tacrolimus therapy have not a significant effect on GCF MPO and MMP-13 levels, and gingival inflammation seems to be the main reason for their elevations.

Gingival crevicular fluid and serum matrix metalloproteinase-8 and tissue inhibitor of matrix metalloproteinase-1 levels in renal transplant patients undergoing different immunosuppressive therapy

AIM

We investigated gingival crevicular fluid (GCF) and serum matrix metalloproteinase-8 (MMP-8) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) levels from renal transplant patients receiving cyclosporine-A (CsA) and having gingival overgrowth (GO), from patients receiving CsA therapy and having no GO and patients receiving tacrolimus therapy.

MATERIAL AND METHODS

GCF samples were collected from sites with GO (GO+) and without GO (GO-) in CsA patients having GO; and GO- sites in CsA patients having no GO; sites from tacrolimus, gingivitis and healthy subjects. GCF and serum MMP-8 and TIMP-1 levels were determined by a time-resolved immunofluorometric assay (IFMA) and enzyme-linked immunosorbent assay.

RESULTS

GO+ sites in CsA patients having GO had elevated GCF MMP-8 levels compared with those of CsA patients having no GO, tacrolimus and healthy subjects (p<0.005), but these levels were similar to those of gingivitis. The GCF MMP-8 level was higher in GO+ compared with GO- sites in CsA patients having GO (p<0.05). GCF TIMP-1 levels were similar between groups. Tacrolimus patients had lower GCF MMP-8 levels than gingivitis (p<0.005), but levels similar to the healthy group.

CONCLUSION

These results show that CsA and tacrolimus therapy has no significant effect on GCF MMP-8 levels, and gingival inflammation seems to be the main reason for their elevations.

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.

A Morphologic Comparison of Gingival Changes Influenced by Cyclosporin and Tacrolimus in Rats: An Experimental Study

BACKGROUND

The aim of this study was to compare the morphologic changes in the gingiva brought about by the administration of cyclosporin and tacrolimus in rats.

METHODS

The study was conducted on 30 six-week-old male Sprague-Dawley rats, divided into three groups of 10 rats each, for a period of 4 weeks. Group I rats received cyclosporin (30 mg/kg body weight), and group II rats received tacrolimus (1.5 mg/kg body weight), by means of a gavage. Group III served as control and received olive oil alone. Impressions of the mandibular incisal region were made weekly, and stone casts were prepared for measuring morphologic changes of the gingiva.

RESULTS

An increase in the measured gingival dimensions was observed in the test groups as early as week 2 after the commencement of drug administration. Intergroup comparison revealed that the increase in the measured dimensions was greater in group I than group II at the end of 4 weeks.

CONCLUSIONS

Cyclosporin and tacrolimus were capable of causing gingival enlargement in Sprague-Dawley rats. However, the magnitude of tacrolimus-influenced gingival enlargement seemed to be comparatively less than cyclosporin.

Morphological and molecular analysis of idiopathic gingival fibromatosis: a case report

AIM

We analyse a case of idiopathic gingival overgrowth using morphological and molecular methods. As this overgrowth involves collagen accumulation in the gingival connective tissue, we measured the collagen turnover to clarify the pathogenic mechanisms potentially involved.

MATERIALS AND METHODS

The patient was a 29-year-old Italian woman with enlargement of the gingivae throughout the entire mandible and maxilla. Morphological analyses were carried out on haematoxylin-eosin and Sirius red-stained paraffin-embedded gingival sections. mRNA levels of collagen type I and III, matrix metalloproteinase (MMP)-1, transforming growth factor-beta1 and lysyl hydroxylase (LH)2b were determined by RT-PCR on cultured gingival fibroblasts and compared with healthy control fibroblasts. Interstitial collagen and MMP-1 content in the supernatants were assessed, respectively, by dot blot and SDS zymography.

RESULTS AND CONCLUSIONS

In Sirius red-stained sections of the patient's overgrown gingivae, interstitial collagen content was 29% higher than controls. Her gingival fibroblasts had higher collagen type I, MMP-1 and LH2b gene expression and unmodified interstitial collagen, type I protein levels in the supernatants. These findings would seem to suggest that in this case collagen accumulation in the gingival connective tissue was not associated with increased synthesis and decreased degradation.