Effect of phenytoin on the production of interleukin-6 and interleukin-8 in human gingival fibroblasts

Impact of phenytoin and valproic acid on cytotoxicity and inflammatory mediators in human mononuclear cells: with and without lipopolysaccharide stimulation

Background

Valproic acid (VPA) is known for its broad-spectrum antiepileptic effects and is recommended for generalized epilepsy, in contrast to phenytoin, which has a more limited spectrum. This study investigated the cytotoxic and inflammatory responses to phenytoin and VPA in peripheral blood mononuclear cells (PBMCs), with and without bacterial lipopolysaccharide (LPS) stimulation.

Methods

PBMCs from healthy donors were divided into 12 groups: control (Ctrl), phenytoin (Phy), and four concentrations of VPA (Val-50, Val-75, Val-100, Val-200), with and without LPS. Assessments were conducted on days 1 and 3, including total, live, and dead cell counts, cell viability, and lactic acid dehydrogenase (LDH) cytotoxicity assays. Inflammatory mediators (IL-6, IL-1β) and immune markers (IL-18, IgA) were measured using enzyme-linked immunosorbent assay (ELISA) on day 3. Statistical analysis involved two-way ANOVA, Tukey's HSD tests, and paired t-tests.

Results

All treatment groups showed significant declines in cell counts and viability from day 1 to day 3, which were exacerbated by LPS. Val-50 + LPS maintained higher cell counts compared to Ctrl + LPS and Phy + LPS. Elevated LDH levels were primarily observed in the Val-100 and Val-200 groups, with and without LPS. In the absence of LPS, the Val-75 and Val-100 groups showed notable reductions in IL-18 and IgA levels, while all VPA treatments reduced IL-6 levels compared to controls. This effect was enhanced under LPS exposure, although IL-1β reductions in the Val-75, Val-100, and Val-200 groups were reversed in the presence of LPS. Val-75 demonstrated lower cytotoxic and inflammatory responses compared to Phy and higher VPA doses, showing moderate LDH increases and reduced IL-18, IgA, IL-1β, and IL-6 levels, particularly under LPS challenge.

Conclusion

Phenytoin and VPA induced significant cytotoxic and inflammatory responses, influenced by dosage and LPS exposure. Val-75 exhibited a dose-specific immunomodulatory effect, reducing both pro-inflammatory and immune markers.

Accelerated wound healing and its promoting effects of topical codeine on the healing of full-thickness cutaneous wound, evidences for modulating cytokines involved in pain, inflammation and collagen biosynthesis

INTRODUCTION

The inflammation and pain occur in all the wounds. Opioids drugs decrease pain and may act as an anti-inflammation. The current study was conducted to investigate the efficiency of the topical uses of Codeine on full-thickness excision wound models by focusing on relationship between pain mediators, inflammation and wound healing rate.

METHODS

Following the induction of anesthesia, a skin wound with a size of 7-mm punch was induced on the dorsal surfaces of each mouse. The mice were divided into five categories: groups I-III were daily administered 2.5%, 5%, and 10% Codeine gel; those in group IV were administered phenytoin cream, and group V (controls) received base ointment. To assess the effects of Codeine gel on the wound healing process, the wound area, histological parameters, and the relative protein expression of CXCR1, CXCR2, IL-6, IL-6R, PDGF, PDGFR, and COL1A along with the plasma concentrations of IL-1β, IL-10, and TNF-α were investigated on days 3, 7, and 14.

RESULTS

On days 7 and 14, the wound area was significantly lower in the treated mice compared to the controls (P < 0.05). Angiogenesis, collagen deposition, and epithelium thickness were significantly higher in the treatment groups compared to the control group (P < 0.05). The relative protein expressions of CXCR1, CXCR2, IL-6, and IL-6R and the plasma concentrations of IL-1β and TNF-α were significantly lower in the treated groups. Meanwhile, the relative protein expressions of PDGF, PDGFR, and COL1A and the plasma concentration of IL-10 were significantly higher in the treated mice (P < 0.05).

CONCLUSION

Administration of Codeine gel accelerated wound healing through decreasing the pain mediators, inflammation and promoting proliferative phase.

Role of IL-6 and STAT3 signaling in dihydropyridine-induced gingival overgrowth fibroblasts

OBJECTIVES

This study analyzed the role of the interleukin (IL)-6/signal transducer and activator of transcription 3 (STAT3) pathway in dihydropyridine-induced gingival overgrowth (DIGO) fibroblasts.

MATERIALS AND METHODS

Tissue samples were obtained through surgical dissection from five DIGO patients and five healthy individuals. Cell cultures were conditioned with nifedipine (Nif) (0.34 µM) and stimulated with IL-1β (10 ng/ml) to clarify whether IL-6 upregulates extracellular matrix overproduction or has an impact on the cell proliferation rate of DIGO fibroblasts. STAT3 was knocked down using short hairpin (sh)RNA to determine its role in collagen (Col) type I alpha 1 (Colα1(I)) synthesis.

RESULTS

Results showed that phosphorylated (p)STAT3 nuclear translocation was activated by a simulated autocrine concentration (50 ng/ml) of IL-6, and application of an anti-IL-6 antibody significantly decreased the pSTAT3/STAT3 ratio in DIGO fibroblasts. STAT3 knockdown significantly decreased STAT3 and Colα1(I) expressions in DIGO cells. DIGO tissues presented stronger proliferating cell nuclear antigen (PCNA) expression than did healthy individuals under the effect of IL-1β/Nif treatment.

CONCLUSIONS

Gingival inflammation (e.g., IL-1β) and taking dihydropyridine (e.g., Nif) may additively stimulate Col overproduction through the IL-6-STAT3-Colα1(I) cascade in DIGO cells. IL-6-STAT3 signaling may be considered a target for the control of DIGO.

Effects of mechanical stress on human oral mucosa-derived cells

OBJECTIVES

Placement of a denture results in the application of mechanical stress (MS), such as occlusal force, onto the oral mucosa beneath the denture. To better understand the molecular mechanism underlying MS-induced inflammation in the oral mucosa, we examined the impact of MS on human oral epithelial cells (HO-1-N-1) and human fibroblasts (HGFs) in this study.

MATERIALS AND METHODS

MS was applied on HO-1-N-1 and HGFs using a hydrostatic pressure apparatus. The expression and production of inflammatory cytokines and growth factors were examined by real-time RT-PCR and ELISA. MS-induced intracellular signal transduction via MAP kinase (MAPK) was also examined.

RESULTS

1 MPa MS resulted in a significant increase in inflammatory cytokines, and 3 MPa MS resulted in a significant increase in FGF-2. MS also increased p-38 phosphorylation and the addition of a p-38 inhibitor significantly suppressed the production of inflammatory cytokines.

DISCUSSION

Our study suggested that MS applied through a denture increases the production of inflammatory cytokines from oral mucosal epithelial cells and fibroblasts via the p38 MAPK cascade. These responses to MS likely lead to inflammation of the mucosal tissue beneath dentures. On other hand, up-regulation of growth factors is likely a manifestation of the biological defense mechanism against excessive MS.

Molecular mechanisms of neuroprotective effect of adjuvant therapy with phenytoin in pentylenetetrazole-induced seizures: Impact on Sirt1/NRF2 signaling pathways

Current anticonvulsant therapies are principally aimed at suppressing neuronal hyperexcitability to prevent or control the incidence of seizures. However, the role of oxidative stress processes in seizures led to the proposition that antioxidant compounds may be considered as promising candidates for limiting the progression of epilepsy. Accordingly, the aim of this study is to determine if coenzyme Q10 (CoQ10) and alpha-tocopherol (α-Toc) have a neuroprotective effect in rats against the observed oxidative stress and inflammation during seizures induced by pentylenetetrazole (PTZ) in rats, and to study their interactions with the conventional antiseizure drug phenytoin (PHT), either alone or in combination. Overall, the data revealed that α-Toc and CoQ10 supplementation can ameliorate PTZ-induced seizures and recommended that nuclear factor erythroid 2-related factor 2 (NRF2) and silencing information regulator 1 (Sirt1) signaling pathways may exemplify strategic molecular targets for seizure therapies. The results of the present study provide novel mechanistic insights regarding the protective effects of antioxidants and suggest an efficient therapeutic strategy to attenuate seizures. Additionally, concurrent supplementation of CoQ10 and α-Toc may be more effective than either antioxidant alone in decreasing inflammation and oxidative stress in both cortical and hippocampal tissues. Also, CoQ10 and α-Toc effectively reverse the PHT-mediated alterations in the brain antioxidant status when compared to PHT only.

Antiepilepsy drugs and the immune system

OBJECTIVE

To alert physicians about the peculiar adverse effects of antiepilepsy drugs (AEDs) on the immune system.

DATA SOURCES

PubMed literature during the past 25 years.

STUDY SELECTIONS

Reports and review articles on the hypersensitivities of AEDs and their effect on immunity.

RESULTS

AEDs have significant effects on the immune system in the form of hypersensitivity or immune suppression. IgE-mediated reactions can be urticaria, angioedema, bronchospasm, or anaphylaxis. Non-IgE-mediated reactions, more commonly associated with aromatic AEDs, can be in the form of nonspecific rashes or serious reactions, such as Stevens-Johnson syndrome, toxic epidermal necrolysis, drug rash with eosinophilia and systemic symptom syndrome, and acute generalized exanthematous pustulosis. Because of strong genetic predispositions for certain AEDs in causing severe reactions, HLA analysis before initiation of the drug is advised in certain populations. Immunoglobulin levels can be reduced to various degrees, particularly by carbamazepine, valproate, phenytoin, levetiracetam, zonisamide, and lamotrigine. Spontaneous return to normal levels can be rapid or take months to a few years, and intravenous immunoglobulin supplementation may be needed. Cellular effects can be in the form of cytopenias, inhibition of lymphocyte function, or cytokine dysregulation.

CONCLUSION

When prescribing AEDs, physicians should pay special attention to their potential adverse effects on immunity or hypersensitivity, which can be severe and even fatal. For early recognition and intervention, monitoring such patients is necessary. The cornerstone of management is discontinued use of the suspected medication and avoidance of drugs of similar structure, particularly among members of the aromatic group.

Connective Tissue Metabolism and Gingival Overgrowth

Gingival overgrowth occurs mainly as a result of certain anti-seizure, immunosuppressive, or antihypertensive drug therapies. Excess gingival tissues impede oral function and are disfiguring. Effective oral hygiene is compromised in the presence of gingival overgrowth, and it is now recognized that this may have negative implications for the systemic health of affected patients. Recent studies indicate that cytokine balances are abnormal in drug-induced forms of gingival overgrowth. Data supporting molecular and cellular characteristics that distinguish different forms of gingival overgrowth are summarized, and aspects of gingival fibroblast extracellular matrix metabolism that are unique to gingival tissues and cells are reviewed. Abnormal cytokine balances derived principally from lymphocytes and macrophages, and unique aspects of gingival extracellular matrix metabolism, are elements of a working model presented to facilitate our gaining a better understanding of mechanisms and of the tissue specificity of gingival overgrowth.

Management of phenytoin-induced gingival enlargement in a patient with antiphospholipid antibody syndrome: A rare case report

Antiphospholipid antibody (APLA) syndrome is a noninflammatory autoimmune disease, with innumerable clinical manifestations ranging from recurrent thrombosis and pregnancy morbidity to valvular lesions, transverse myelitis, thrombocytopenia, and hemolytic anemia. APLAs in antiphospholipid syndrome (APS) are well-known risk factors for cerebrovascular accidents. Stroke is the most common manifestation of APS in the central nervous system. Gingival enlargement is a known side effect of phenytoin which is an antiepileptic drug. This can have a significant effect on the quality of life as well as increasing the oral bacterial load by generating plaque retention sites. The management of gingival overgrowth seems to be directed at controlling gingival inflammation through a good oral hygiene regimen. Thus, this case report aims to describe the conservative management of phenytoin-induced gingival enlargement combined with inflammatory enlargement in a patient with APLA syndrome.

Immunoexpression of interleukin-6 in drug-induced gingival overgrowth patients

BACKGROUND

To analyze the role of proinflammatory cytokines in drug-induced gingival enlargement in Indian population.

AIM

To evaluate for the presence of interleukin-6 (IL-6) in drug-induced gingival enlargement and to compare it with healthy control in the absence of enlargement.

MATERIALS AND METHODS

Thirty-five patients selected for the study and divided into control group (10) and study group (25) consisting of phenytoin (10); cyclosporin (10) and nifedipine (5) induced gingival enlargement. Gingival overgrowth index of Seymour was used to assess overgrowth and allot groups. Under LA, incisional biopsy done, tissue sample fixed in 10% formalin and immunohistochemically evaluated for the presence of IL-6 using LAB-SA method, Labeled- Streptavidin-Biotin Method (LAB-SA kit from Zymed- 2(nd) generation LAB-SA detection system, Zymed Laboratories, CA). The results of immunohistochemistry were statistically analyzed using Kruskaal-Wallis and Mann-Whitney test.

RESULTS

The data obtained from immunohistochemistry assessment shows that drug-induced gingival overgrowth (DIGO) samples express more IL-6 than control group and cyclosporin expresses more IL-6 followed by phenytoin and nifedipine.

CONCLUSION

Increased IL-6 expression was noticed in all three DIGO groups in comparison with control group. Among the study group, cyclosporin expressed maximum IL-6 expression followed by phenytoin and nifedipine.

Wound Healing Potential of Topical Amlodipine in Full Thickness Wound of Rabbit

Background:

Wound healing is a complicated and integrated process. Researches have indicated the wound healing effects of calcium channel blockers in animal models in recent years.

Objectives:

The aim of this study was to evaluate the wound-healing activity of amlodipine as a calcium channel blocker and combination of amlodipine with phenytoin on excisional cutaneous wound models in rabbit.

Materials and Methods:

Animals were divided into 5 groups (n = 5). The control group was treated topically with eucerin. The untreated control group received no healing agent. The reference standard group was treated with phenytoin1%. A treatment group was treated with amlodipine 1%. The last group was treated with combination of amlodipine1% and phenytoin 1%.

Results:

Results indicated significant difference between days needed for complete healing in both of the treatment groups. Wound closure was completed on 13th day and 9th day in amlodipine and combination groups respectively.

Conclusions:

In conclusion, calcium channel blockers can be used to enhance wound healing, especially if this treatment becomes with phenytoin. Further studies are needed to find out the mechanism of this healing effect.

Proliferative and inductive effects of Cyclosporine a on gingival fibroblast of child and adult

Background:

Gingival overgrowth is a serious side-effect that accompanies the use of Cyclosporin A (CsA). Up to 97% of the transplant recipient children, who were submitted to CsA therapy, have been reported to suffer from this side-effect. Several conflicting theories have been proposed to explain the fibroblast's function in CsA-induced gingival overgrowth. The aim of this study is to assess the proliferation of gingival fibroblasts and levels of released cytokines after being exposed to CsA, in both adults and pediatric groups, and to make a comparison between the results of the two groups.

Materials and Methods:

The adult fibroblast samples were derived from four healthy adults, aged 35 to 42 years and pediatric samples were obtained from four healthy children, age between four and eleven years. Tissue samples were plated in Dulbecco's Modified Eagle Medium (DMEM) containing 10% fetal bovine serum (FBS), Streptomycin and Penicillin. The samples were cultured in 25 cm² plates containing 5% CO2, and incubated at 37°C. The cells used for all the experiments were at the fourth passage. The concentration of PGE₂, IL-1β, IL-6, IL-8, TNF-α, and TGF-β₁ was determined by the enzyme-linked immunosorbent assay (ELISA) and the proliferation rate was assessed by the MTT assay. Alpha error levels were set as 0.05.

Results:

CsA stimulated significantly higher levels of IL-6, IL-8 and TGF-β₁ in adult gingival fibroblasts than it did in the control group; whereas, the expression of IL-1β and PGE₂ in the fibroblasts exposed to CsA was significantly weaker (P < 0.05). The fibroblasts in the two groups did not reveal any noticeable difference in the production of TNF-α. Furthermore, cell proliferation in the CsA group was not significantly higher than that in the control group. No significant differences in cytokines TNF-α and IL-1β were noted between the two groups. The results indicated that CsA stimulated cell proliferation in the pediatric fibroblast cell line. Comparison between the results in the adult and pediatric groups demonstrated that the levels of IL-1β, IL-6, IL-8, and PGE₂ were significantly higher in the pediatric group than in the adult group; however, statistics showed no significant difference in the levels of TNF-α and TGF-β₁ and CsA-induced proliferation between these two groups.

Conclusions:

The mechanism of a CsA-induced fibroblast overgrowth may converge on the steps involving fibroblast proliferation and cytokine network including IL-6, IL-8, IL-1β, TGF-β₁, and PGE₂, in both adults and pediatrics. As the prevalence and intensity of drug-induced gingival overgrowth is more serious in the pediatrics. As group than in adults, we suggest that more studies be conducted on the pediatric group.

Phenytoin-induced gingival overgrowth

Gingival overgrowth is a common adverse effect of therapy with Phenytoin, having important medical and cosmetic implications. Poor periodontal hygiene is an important risk factor for severity of Phenytoin-induced gingival overgrowth (PIGO), which is a time-dependent process. There is complex interplay of altered fibroblast biology, connective tissue turnover, inflammatory processes, and growth factors on a background of genetic susceptibility to produce increase in various components of interstitial matrix in PIGO tissue. Treatment options have included change of PHT to another anti-seizure drug, measures to improve periodontal hygiene and gingivectomy. There is conclusive evidence that folic acid supplementation significantly decreases the incidence of PIGO.

Effect of cannabidiol on human gingival fibroblast extracellular matrix metabolism: MMP production and activity, and production of fibronectin and transforming growth factor β

BACKGROUND AND OBJECTIVE

Marijuana (Cannabis sativa) use may be associated with gingival enlargement, resembling that caused by phenytoin. Cannabidiol (CBD), a nonpsychotropic Cannabis derivative, is structurally similar to phenytoin. While there are many reports on effects of phenytoin on human gingival fibroblasts, there is no information on effects of Cannabis components on these cells. The objective of this study was to determine effects of CBD on human gingival fibroblast fibrogenic and matrix-degrading activities.

MATERIAL AND METHODS

Fibroblasts were incubated with CBD in serum-free medium for 1-6 d. The effect of CBD on cell viability was determined by measuring activity of a mitochondrial enzyme. The fibrogenic molecule transforming growth factor β and the extracellular matrix molecule fibronectin were measured by ELISA. Pro-MMP-1 and total MMP-2 were measured by ELISA. Activity of MMP-2 was determined via a colorimetric assay in which a detection enzyme is activated by active MMP-2. Data were analysed using ANOVA and Scheffe's F procedure for post hoc comparisons.

RESULTS

Cannabidiol had little or no significant effect on cell viability. Low CBD concentrations increased transforming growth factor β production by as much as 40% (p < 0.001), while higher concentrations decreased it by as much as 40% (p < 0.0001). Cannabidiol increased fibronectin production by as much as approximately 100% (p < 0.001). Lower CBD concentrations increased MMP production, but the highest concentrations decreased production of both MMPs (p < 0.05) and decreased MMP-2 activity (p < 0.02).

CONCLUSION

The data suggest that the CBD may promote fibrotic gingival enlargement by increasing gingival fibroblast production of transforming growth factor β and fibronectin, while decreasing MMP production and activity.

Phenytoin-induced gingival overgrowth: a review of the molecular, immune, and inflammatory features

Gingival overgrowth (GO) is a side effect associated with some distinct classes of drugs, such as anticonvulsants, immunosuppressant, and calcium channel blockers. GO is characterized by the accumulation of extracellular matrix in gingival connective tissues, particularly collagenous components, with varying degrees of inflammation. One of the main drugs associated with GO is the antiepileptic phenytoin, which affects gingival tissues by altering extracellular matrix metabolism. Nevertheless, the pathogenesis of such drug-induced GO remains fulfilled by some contradictory findings. This paper aims to present the most relevant studies regarding the molecular, immune, and inflammatory aspects of phenytoin-induced gingival overgrowth.

Antiepileptic drugs and the immune system

Data on the effects of antiepileptic drugs on the immune system are frequently inconsistent and sometimes conflicting because the effects of drugs cannot be separated from those of seizures, first-generation drugs have been most intensively investigated, the patient's genetic background, the mechanism of action and the pharmacokinetic profile of AEDs and the concurrent use of immunosuppressant drugs may act as confounders. Valproate, carbamazepine, phenytoin, vigabatrin, levetiracetam, and diazepam have been found to modulate the immune system activity by affecting humoral and cellular immunity. AEDs are associated with pharmacokinetic interactions (most frequently occurring with carbamazepine, phenytoin, phenobarbital and valproate). Hepatic metabolism is the primary site of interaction for both AEDs and immunotherapies (ACTH, dexamethasone, hydrocortisone, methylprednisolone, cyclophosphamide, methotrexate, rituximab), which entail induction or inhibition of drug effects. However, the clinical importance of these drug interactions is still far from defined. An important adverse effect of the action of AEDs on the immune system is antiepileptic hypersensitivity syndrome (AHS), a life-threatening, idiosyncratic cutaneous reaction to aromatic AEDs resulting in end organ damage. Phenytoin, carbamazepine, phenobarbital, lamotrigine, oxcarbazepine, felbamate, and zonisamide have been implicated. The pathogenic mechanisms of AHS are incompletely understood.

Cyclosporin A and phenytoin modulate inflammatory responses

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

Autoantibodies to beta1-adrenoceptors in human chronic periodontitis induce overexpression of fibroblast CD40 and trigger prostaglandin E2 generation

BACKGROUND AND OBJECTIVE

Autoimmune mechanisms may contribute to the pathogenesis of periodontal disease. Autoantibodies with the potential to bind and activate beta(1)-adrenoceptors (beta(1)-AR) of human gingival fibroblasts were studied to provide evidence of altered humoral immune response in chronic periodontal disease.

MATERIAL AND METHODS

Flow cytometry and enzyme-linked immunosorbent assay using cell culture-adherent gingival fibroblasts and/or their purified membranes and/or a synthetic peptide corresponding to the second extracellular loop of human beta(1)-AR were used to detect serum antibodies. The effects of antibodies from chronic periodontal disease patients on PGE(2) generation and CD40 expression were also tested.

RESULTS

Circulating immunoglobulin G (IgG) from chronic periodontal disease patients (but not from normal individuals) interacted with the fibroblast surface, activating beta(1)-AR. Atenolol or CGP 20712 (beta 1-AR antagonists) and beta(1) synthetic peptide inhibited the interaction of IgG with beta(1)-AR. Immunoglobulin G from chronic periodontal disease patients also displayed agonist-like activity associated with specific beta(1)-AR activation, increasing PGE(2) generation and CD40 overexpression. The corresponding affinity-purified anti-beta(1)-AR peptide IgG mimicked these effects. Both effects were prevented by inhibition of cyclo-oxygenase.

CONCLUSION

This article supports the participation of humoral immune alterations in chronic periodontal disease resulting in postsynaptic functional deregulation. Overproduction of proinflammatory mediators (PGE(2) and CD40 expression) is induced as a consequence of antibody-beta(1)-AR interaction. The PGE(2)-CD40-IgG axis may play a part in the pathophysiological mechanisms underlying the inflammatory process in chronic periodontal disease.

Plasma and gingival crevicular fluid phenytoin concentrations as risk factors for gingival overgrowth

BACKGROUND

Gingival enlargement is one of the side effects associated with the administration of phenytoin. The mechanism by which phenytoin induces gingival enlargement is not well understood. This study was conducted to investigate the relationship between plasma and gingival crevicular fluid (GCF) phenytoin concentrations and the degree of gingival overgrowth in patients with similar gingival and plaque indices and also to determine the risk factors for gingival enlargement.

METHODS

Eighteen patients taking phenytoin in regular doses > or =6 months prior to the investigation participated in the study. Gingival enlargement was evaluated with two indices to score vertical and horizontal overgrowth. The gingival index (GI), plaque index (PI), gingival bleeding time index (GBTI), probing depth (PD), and clinical attachment level (CAL) were also evaluated. GCF and plasma phenytoin concentrations were determined by using high-performance liquid chromatography (HPLC).

RESULTS

There was no significant difference between responders and non-responders for PD, CAL, PI, GI, and GBTI. Phenytoin was detected in all of the GCF and plasma samples using the HPLC analysis method. The mean concentration of phenytoin in GCF was significantly greater than the concentration of phenytoin in plasma. No significant difference was observed for the concentration of GCF phenytoin between responders and non-responders. However, the concentration of plasma phenytoin was significantly higher in responders than non-responders.

CONCLUSION

This study showed that plasma phenytoin level appeared to be a risk factor for phenytoin-induced gingival overgrowth.

Epidermal growth factor synergistically enhances interleukin-8 production in human gingival fibroblasts stimulated with interleukin-1beta

The chemokine interleukin-8 (IL-8) has been implicated in inflammatory diseases including periodontitis. In this study the effect of epidermal growth factor (EGF) on the production and regulation of interleukin-8 (IL-8) in human gingival fibroblasts challenged with interleukin-1beta (IL-1beta) was investigated. EGF, in comparison to the effect of IL-1beta, weakly increased the mRNA and protein expression of IL-8 in gingival fibroblasts. When the cells were treated simultaneously with EGF and IL-1beta, however, EGF synergistically enhanced the mRNA expression and production of IL-8. The stimulatory effect of EGF on IL-1beta-induced IL-8 production was completely abolished by the broad range tyrosine kinase inhibitor Herbimycin A, and considerably reduced by the receptor tyrosine kinase specific inhibitor PD 153035. Herbimycin A abolished IL-8 production induced by IL-1beta, whereas PD 153035 had no effect on the cytokine-induced IL-8 production. Furthermore, the p38 mitogen-activated protein (MAP) kinase inhibitor SB 203580 reduced IL-8 production induced by IL-1beta as well as by the combination of EGF and IL-1beta but had no effect on EGF-induced IL-8 production. In conclusion, the study demonstrates that EGF synergistically stimulates IL-8 production in the presence of IL-1beta and that tyrosine kinase(s) seem to be involved in the signalling pathway of IL-1beta and EGF. The synergistic interactions between EGF and IL-1beta on IL-8 production may play an essential role in the pathogenesis of the inflammatory disease periodontitis.

Impaired degradation of matrix collagen in human gingival fibroblasts by the antiepileptic drug phenytoin

BACKGROUND

Gingival overgrowth (GO) is a serious adverse effect associated with the administration of phenytoin (PHT), with PHT-induced GO characterized by a massive accumulation of extracellular matrix components, especially collagen, in gingival connective tissues. However, the etiology of such collagen accumulation is still largely unknown. We examined the effects of PHT on the collagen degradation process leading to collagen accumulation in human gingival fibroblasts (HGF).

METHODS

HGFs were cultured with various concentrations of PHT and viable cell numbers and collagen amounts were determined. Gene and protein expressions of matrix metalloproteinases (MMP) and tissue inhibitors of MMPs (TIMP) were quantified with reverse transcription-polymerase chain reaction (RT-PCR) analyses and Western blotting, respectively. Cellular endocytosis of collagen was assayed using flow-cytometric analysis. The effects of PHT on extracellular signal-regulated kinase 1/2 (ERK1/2) and inhibitor kappaB-alpha (IkappaB-alpha) were assayed.

RESULTS

The proliferation of HGFs was not affected by PHT, whereas it significantly increased collagen accumulation. Further, the expressions of MMP-1, -2, and -3 were markedly suppressed by PHT, whereas that of TIMP-1 was induced in a dose- and time-dependent manner. PHT also markedly prevented collagen endocytosis by HGFs, which was associated with the suppression of alpha2beta1-integrin expression. In addition, the phosphorylation of ERK1/2 and IkappaB-alpha degradation were suppressed by PHT.

CONCLUSIONS

These results suggest that PHT causes an impaired degradation of collagen by suppression of enzymatic degradation with MMPs/TIMP-1 and alpha2beta1-integrin-mediated endocytosis. Those alterations are likely mediated through the cellular signaling pathways of ERK1/2 and nuclear factor kappaB. These synergistic effects may cause collagen accumulation, leading to GO.

Bradykinin upregulates IL-8 production in human gingival fibroblasts stimulated by interleukin-1beta and tumor necrosis factor alpha

The proinflammatory mediator bradykinin (BK) is suggested to play an important role in the pathogenesis of various inflammatory diseases including periodontitis. In this study, BK per se stimulated interleukin-8 (IL-8) production in human gingival fibroblasts in vitro. Furthermore, BK upregulated the stimulatory effect of the cytokines IL-1beta and TNFalpha on the production of IL-8. The stimulatory effect of BK on the IL-1beta- or TNFalpha-stimulated IL-8 production was reduced in the presence of BK B2 receptor antagonist HOE 140, whereas the B1 receptor antagonist Lys-(des-arg9, Leu8)-BK had no effect. Similar to BK, the calcium ionophore A23187 also upregulated the stimulatory effect of IL-1beta and TNFalpha on IL-8 production. The protein kinase C (PKC) inhibitor bisindolylmaleimide, BIS, significantly reduced the stimulatory effect of BK on IL-1beta and TNFalpha increased IL-8 production but did not affect the production of IL-8 stimulated by cytokines alone. The specific p38 mitogen-activated protein kinase (MAPK) inhibitor SB 203580 reduced IL-8 production stimulated by the combination of BK and IL-1beta as well as the IL-1beta-stimulated IL-8 production. In conclusion, this study shows that BK upregulates IL-1beta- and TNFalpha-stimulated IL-8 production via BK B2 receptor and that PKC signal pathway seems to be involved in the upregulation of the cytokine-induced IL-8 production in gingival fibroblasts. This stimulatory effect of BK on IL-8 production may contribute to the maintenance of the gingival inflammation and enhanced risk for destruction of gingival connective tissue.

Gingival enlargement in children treated with antiepileptics

This study was conducted to determine the occurrence, severity, and risk factors of gingival enlargement in children treated with valproate and other nonvalproate antiepileptic drugs. A cross-sectional study was carried out in which data obtained from 68 epileptic children under treatment were compared with those from 50 controls. A structured questionnaire was used to collect data on patients' demographics, dental and oral hygiene practices, and medication history. Gingival enlargement, gingival index, plaque index, and probing depth were measured to assess periodontal health. The chi-square and Fisher exact tests were used in statistical analysis. In case of significance, a detailed chi-square analysis was carried out to determine the origin of the difference. Patients in both the valproate and nonvalproate groups showed significantly higher gingival enlargement, gingival index, plaque scores, and pocketing (P < .001 and P < .01, respectively) than the control group. In the valproate group, the duration of the treatment had a significant effect on gingival enlargement (P < .001) but not on gingival index, plaque index, and probing depth values (P > .05). Toothbrushing was most frequent in the control group (P = .000) and more frequent in the valproate group than the nonvalproate group (P = .024). Our study showed significant differences regarding gingival enlargement in children treated with valproate. These findings illustrate that epileptic children on valproate are at risk of periodontal problems.

Modulation of androgen metabolism by phenytoin, oestradiol and tamoxifen in human gingival fibroblasts

OBJECTIVES

The aim of this investigation is to study androgen metabolism in gingival fibroblasts in response to phenytoin, oestradiol and the antioestrogen tamoxifen, in order to establish the possible role of hormones in the aetiopathogenesis of phenytoin-induced gingival overgrowth.

MATERIALS AND METHODS

Six cell lines of human gingival fibroblasts were established in monolayer culture in Eagle's minimum essential medium. Duplicate incubations were performed independently with radiolabelled testosterone and 4-androstenedione, respectively (14C-T/14C-4-A), with optimal concentrations of phenytoin, oestradiol and tamoxifen alone and in combination. At the end of a 24-h incubation period, the medium was solvent extracted for steroid metabolites, which were separated by thin layer chromatography and quantified using a radioisotope scanner.

RESULTS

The substrates were metabolised mainly to the diols, 5alpha-dihydrotestosterone (DHT) and 4-androstenedione or testosterone, with the two substrates used. The trends were that phenytoin and oestradiol significantly elevated the yields of the androgens DHT, diols and 4-A/testosterone from both substrates while tamoxifen inhibited the stimulatory effects of oestradiol and phenytoin alone and in combination (n=6; p<0.01, one-way anova).

CONCLUSION

Specific hormone-mediated activity in response to phenytoin could contribute to the pathogenesis of gingival overgrowth, which can be decreased by the anti oestrogen tamoxifen.