Loss of TBC1D2B causes a progressive neurological disorder with gingival overgrowth.

Biallelic loss-of-function variants in TBC1D2B have been reported in five subjects with cognitive impairment and seizures with or without gingival overgrowth. TBC1D2B belongs to the family of Tre2-Bub2-Cdc16 (TBC)-domain containing RAB-specific GTPase activating proteins (TBC/RABGAPs). Here, we report five new subjects with biallelic TBC1D2B variants, including two siblings, and delineate the molecular and clinical features in the ten subjects known to date. One of the newly reported subjects was compound heterozygous for the TBC1D2B variants c.2584C>T; p.(Arg862Cys) and c.2758C>T; p.(Arg920*). In subject-derived fibroblasts, TBC1D2B mRNA level was similar to control cells, while the TBC1D2B protein amount was reduced by about half. In one of two siblings with a novel c.360+1G>T splice site variant, TBC1D2B transcript analysis revealed aberrantly spliced mRNAs and a drastically reduced TBC1D2B mRNA level in leukocytes. The molecular spectrum included 12 different TBC1D2B variants: seven nonsense, three frameshifts, one splice site, and one missense variant. Out of ten subjects, three had fibrous dysplasia of the mandible, two of which were diagnosed as cherubism. Most subjects developed gingival overgrowth. Half of the subjects had developmental delay. Seizures occurred in 80% of the subjects. Six subjects showed a progressive disease with mental deterioration. Brain imaging revealed cerebral and/or cerebellar atrophy with or without lateral ventricle dilatation. The TBC1D2B disorder is a progressive neurological disease with gingival overgrowth and abnormal mandible morphology. As TBC1D2B has been shown to positively regulate autophagy, defects in autophagy and the endolysosomal system could be associated with neuronal dysfunction and the neurodegenerative disease in the affected individuals.

Biallelic frameshift variant in the TBC1D2B gene in two siblings with progressive gingival overgrowth, fibrous dysplasia of face, and mental deterioration.

Biallelic loss-of-function variants in the TBC1D2B gene were recently reported as a cause of a neurodevelopmental disorder with seizures and gingival overgrowth. Here, we report two male siblings with the similar clinical characteristics. They started with gingival overgrowth and bilateral growth of soft tissues in the malar region at 3 years of age, which evolved with significant maxillary hypertrophy and compression of the brainstem due to fibrous dysplasia of facial bones. After disease evolution, they presented with mental deterioration, limb tremors, and gait ataxia. One of them also presented with seizures. Whole exome sequencing revealed a novel biallelic frameshift variant [c.595del; p.(Val199Trpfs*22)] in the TBC1D2B gene in both patients, which was confirmed and found in heterozygous state in each of their parents. There are strong similarities in clinical characteristics, age of onset, and evolution between the patients described here and cases reported in the literature, including cherubism-like phenotype with progressive gingival overgrowth and seizures. This is the fourth family in the world in which a biallelic loss-of-function variant in the TBC1D2B gene is associated with this phenotype. These results support that loss of TBC1D2B is the cause of this rare condition.

Biallelic loss-of-function variants in TBC1D2B cause a neurodevelopmental disorder with seizures and gingival overgrowth.

The family of Tre2-Bub2-Cdc16 (TBC)-domain containing GTPase activating proteins (RABGAPs) is not only known as key regulatorof RAB GTPase activity but also has GAP-independent functions. Rab GTPases are implicated in membrane trafficking pathways, such as vesicular trafficking. We report biallelic loss-of-function variants in TBC1D2B, encoding a member of the TBC/RABGAP family with yet unknown function, as the underlying cause of cognitive impairment, seizures, and/or gingival overgrowth in three individuals from unrelated families. TBC1D2B messenger RNA amount was drastically reduced, and the protein was absent in fibroblasts of two patients. In immunofluorescence analysis, ectopically expressed TBC1D2B colocalized with vesicles positive for RAB5, a small GTPase orchestrating early endocytic vesicle trafficking. In two independent TBC1D2B CRISPR/Cas9 knockout HeLa cell lines that serve as cellular model of TBC1D2B deficiency, epidermal growth factor internalization was significantly reduced compared with the parental HeLa cell line suggesting a role of TBC1D2B in early endocytosis. Serum deprivation of TBC1D2B-deficient HeLa cell lines caused a decrease in cell viability and an increase in apoptosis. Our data reveal that loss of TBC1D2B causes a neurodevelopmental disorder with gingival overgrowth, possibly by deficits in vesicle trafficking and/or cell survival.

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.

Elevated Interleukin-17A expression in amlodipine-induced gingival overgrowth.

BACKGROUND AND OBJECTIVES: Amlodipine, a calcium channel blocker derivative, is frequently used by patients with high blood pressure. Studies reported that it can induce gingival overgrowth. However, the underlying mechanism is not fully described yet. Interleukin-17A (IL-17A) is known as a proinflammatory cytokine, but current studies indicate that it has a role in fibrotic disorders and epithelial-mesenchymal transition (EMT). The aim of this study was to figure out the possible role of IL-17A in amlodipine-induced gingival overgrowth. MATERIALS AND METHODS: Twenty-nine (29) individuals participated in the study, and they were assigned into 3 groups based on medical status and clinical periodontal examination; 9 patients with amlodipine-induced gingival overgrowth, 11 patients with inflammatory gingival overgrowth, and 9 healthy individuals as a control group. Clinical periodontal parameters including plaque index (PI), gingival index (GI), and gingival overgrowth index (GOI) were recorded. Blood and gingival crevicular fluid (GCF) samples were obtained. Gingival tissues were taken by appropriate periodontal surgery following initial periodontal therapy. To detect IL-17A on tissue samples, immunohistochemistry (IHC) was performed. Quantitative analysis was done, and the expression level of IL-17A was given as the percent positively stained cells. Enzyme-linked immunosorbent assay (ELISA) kits were used to analyze IL-17A in serum and GCF samples. RESULTS: All recorded clinical parameters were significantly higher in gingival overgrowth groups compared with control. Evaluation of inflammation on tissue sections did not show any significant change within the groups. Immunohistochemistry findings showed that IL-17A expression was increased in amlodipine samples (81.90%) compared with control samples (42.35%) (P < .001). There was an increase in the inflammatory group (66.08%) which is significantly less than the amlodipine group (P < .05). IL-17A levels in serum and GCF samples were not different within the study groups. CONCLUSION: In this study, elevated IL-17A expression regardless of inflammation shows that amlodipine might cause an increase of IL-17A in gingival tissues. This increase might induce fibrotic changes and EMT in gingival overgrowth tissues. The association of IL-17A with fibrosis and EMT in gingival tissues requires further investigation.

Molecular Aspects of Drug-Induced Gingival Overgrowth: An In Vitro Study on Amlodipine and Gingival Fibroblasts.

Gingival overgrowth is a serious side effect that accompanies the use of amlodipine. Several conflicting theories have been proposed to explain the fibroblast's function in gingival overgrowth. To determine whether amlodipine alters the fibrotic response, we investigated its effects on treated gingival fibroblast gene expression as compared with untreated cells. MATERIALS AND METHODS: Fibroblasts from ATCC® Cell Lines were incubated with amlodipine. The gene expression levels of 12 genes belonging to the "Extracellular Matrix and Adhesion Molecules" pathway was investigated in treated fibroblasts cell culture, as compared with untreated cells, by real time PCR. RESULTS: Most of the significant genes were up-regulated. (CTNND2, COL4A1, ITGA2, ITGA7, MMP10, MMP11, MMP12, MMP26) except for COL7A1, LAMB1, MMP8, and MMP16, which were down-regulated. CONCLUSION: These results seem to demonstrate that amlodipine has an effect on the extracellular matrix of gingival fibroblast. In the future, it would be interesting to understand the possible effect of the drug on fibroblasts of patients with amlodipine-induced gingival hyperplasia.

Lack of Association Between TGF-ß1 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-ß1 and MDR1 gene polymorphisms on the pathogenesis of CsA-induced GO remains to be determined. This study aimed to determine the association between TGF-ß1 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-ß1 +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-ß1 +869T>C, and +915G>C and MDR1 C3435T gene polymorphisms and the pathogenesis of CsA-induced GO in kidney transplant recipients.

Systematic review of cyclosporin A-induced gingival overgrowth and genetic predisposition.

OBJECTIVE: This systematic review aimed to investigate the influence of gene polymorphisms on the development of gingival overgrowth in renal transplant patients treated with cyclosporin A. METHOD AND MATERIALS: Electronic and hand literature searches were conducted by two independent reviewers in MEDLINE-Pubmed, Cochrane Library, ISI Web of Science, and SCOPUS Elsevier for prospective (case-control studies, cohort studies), cross-sectional, and retrospective studies published up to June 2016 (first week) in any language. Data were reviewed and extracted in duplicate independently. Methodologic quality assessment of the included studies was performed during the data extraction process. RESULTS: Due to the estimated high risk of bias and the heterogeneity of the included studies in regards to the variety of medications administered to study patients, a systematic review of the literature and not a meta-analysis of the data was performed. Fourteen articles meeting study inclusion criteria were selected for data extraction that examined the association between various genetic polymorphisms and gingival overgrowth in kidney transplant patients receiving cyclosporin A. Interleukin-1A, interleukin-10, transforming growth factor-ß1 and androgen receptor gene polymorphisms may have a significant effect on an individual susceptibility to cyclosporin A-induced gingival overgrowth in renal transplant patients. CONCLUSION: Genetic polymorphisms seem to affect the development of cyclosporin A-induced gingival overgrowth in renal transplant patients. Pharmacogenetics and pharmacogenomics have the potential to determine the clinical outcome of a medication, the drug efficacy, and adverse drug reactions such as gingival overgrowth.

Lack of pathogenic mutations in SOS1 gene in phenytoin-induced gingival overgrowth patients.

OBJECTIVE: Gingival overgrowth is a side effect associated with some distinct classes of drugs, such as anticonvulsants, immunosuppressants, and calcium channel blockers. One of the main drugs associated with gingival overgrowth is the antiepileptic phenytoin, which affects gingival tissues by altering extracellular matrix metabolism. It has been shown that mutation of human SOS1 gene is responsible for a rare hereditary gingival fibromatosis type 1, a benign gingival overgrowth. The aim of the present study is to evaluate the possible contribution of SOS1 mutation to gingival overgrowth-related phenotype. DESIGN: We selected and screened for mutations a group of 24 epileptic patients who experienced significant gingival overgrowth following phenytoin therapy. Mutation scanning was carried out by denaturing high-performance liquid chromatography analysis of the entire coding region of the SOS1 gene. Novel identified variants were analyzed in-silico by using Alamut Visual mutation interpretation software, and comparison with normal control group was done. RESULTS: Mutation scanning of the entire coding sequence of SOS1 gene identified seven intronic variants and one new exonic substitution (c.138G>A). The seven common intronic variants were not considered to be of pathogenic importance. The exonic substitution c.138G>A was found to be absent in 100 ethnically matched normal control chromosomes, but was not expected to have functional significance based on prediction bioinformatics tools. CONCLUSIONS: This study represents the first mutation analysis of the SOS1 gene in phenytoin-induced gingival overgrowth epileptic patients. Present results suggest that obvious pathogenic mutations in the SOS1 gene do not represent a common mechanism underlying phenytoin-induced gingival overgrowth in epileptic patients; other mechanisms are likely to be involved in the pathogenesis of this drug-induced phenotype.

Upregulation of Slug expression by cyclosporine A contributes to the pathogenesis of gingival overgrowth.

BACKGROUND/PURPOSE: Gingival overgrowth occurs as a side effect of systemic medication with immunosuppressant cyclosporine A (CsA). Slug, a master regulator of epithelial-mesenchymal transition, is dramatically upregulated in a variety of fibrotic diseases. The aim of this study is to investigate the role of epithelial-mesenchymal transition marker Slug in the pathogenesis of CsA-induced gingival overgrowth. METHODS: Clinically healthy gingiva and CsA-induced gingival overgrowth specimens were analyzed by immunohistochemistry. The effect of CsA on normal human gingival fibroblasts (HGFs) was used to elucidate whether Slug expression could be affected by CsA by real-time reverse transcription-polymerase chain reaction and western blot. Cell proliferation in CsA-treated HGFs with Slug lentiviral-mediated shRNAi knockdown was evaluated by tetrazolium bromide reduction assay. RESULTS: Slug expression was higher in CsA-induced gingival overgrowth specimens than in clinical healthy gingiva (p < 0.05). Slug expression was significantly higher in CsA-induced gingival overgrowth specimens with higher levels of inflammatory infiltrates (p < 0.05). CsA was found to increase Slug transcript and protein expression in HGFs in a dose-dependent manner (p < 0.05). In addition, knockdown of Slug significantly suppressed CsA-induced cell proliferation in HGFs (p < 0.05). CONCLUSION: Taken together, upregulation of Slug in HGFs stimulated by CsA may play an important role in the pathogenesis of CsA-induced gingival overgrowth.

Cellular crosstalk mechanism of Toll-like receptors in gingival overgrowth (review).

Gingival overgrowth is an undesirable outcome of systemic medication and is evidenced by the accretion of collagenous components in gingival connective tissues along with diverse degrees of inflammation. Phenytoin therapy has been found to induce the most fibrotic lesions in gingiva, cyclosporine caused the least fibrotic lesions, and nifedipine induced intermediate fibrosis in drug­induced gingival overgrowth. In drug­induced gingival overgrowth, efficient oral hygiene is compromised and has negative consequences for the systemic health of the patients. Toll­like receptors (TLRs) are involved in the effective recognition of microbial agents and play a vital role in innate immunity and inflammatory signaling responses. TLRs stimulate fibrosis and tissue repairs in several settings, although with evident differences between organs. In particular, TLRs exert a distinct effect on fibrosis in organs with greater exposure to TLR ligands, such as the gingiva. Cumulative evidence from diverse sources suggested that TLRs can affect gingival overgrowth in several ways. Numerous studies have demonstrated the expression of TLRs in gingival tissues and suggested its potential role in gingival inflammation, cell proliferation and synthesis of the extracellular matrix which is crucial to the development of gingival overgrowth. In the present review, we assessed the role of TLRs on individual cell populations in gingival tissues that contribute to the progression of gingival inflammation, and the involvement of TLRs in the development of gingival overgrowth. These observations suggest that TLRs provide new insight into the connection among infection, inflammation, drugs and gingival fibrosis, and are therefore efficient therapeutic target molecules. We hypothesize that TLRs are critical for the development and progression of gingival overgrowth, and thus blocking TLR expression may serve as a novel target for antifibrotic therapy.

The role of androgen receptor gene in cyclosporine induced gingival overgrowth.

BACKGROUND AND OBJECTIVE: Gingival overgrowth is a prominent side effect of cyclosporine (CsA) therapy in renal transplant patients. Although the exact mechanism by which this drug induces gingival overgrowth is uncertain, marked variations in individual susceptibility to this drug suggest a genetic predisposition. Studies have shown that genetic variation (polymorphism) in the trinucleotide cytosine-adenine- guanine (CAG) sequence in exon 1 of the androgen receptor (AR) gene is related to altered activity of the AR as a transcription factor. However, the relationship between the length of the CAG repeat and gingival overgrowth has not yet been studied. The present study was carried out to determine whether there is an association between CsA-induced gingival overgrowth and the length of the CAG repeats in the AR gene. MATERIAL AND METHODS: Genomic DNA samples were prepared from the blood of 50 renal transplant patients with CsA-induced gingival overgrowth and from the blood of 100 renal transplant patients on CsA with no gingival overgrowth. RESULTS: The difference in allele distribution among the subjects with gingival overgrowth and control samples was statistically significant (p = 0.001). CONCLUSION: The findings suggest a link between CsA7induced gingival overgrowth and a smaller size of CAG repeat in the AR gene.

Comprehensive mutation analysis of PIK3CA, p14ARF, p16INK4a and p21Waf1/Cip1 genes is suggestive of a non- neoplastic nature of phenytoin induced gingival overgrowth.

BACKGROUND: Dilantin sodium (phenytoin) is an antiepileptic drug, which is routinely used to control generalized tonic clonic seizure and partial seizure episodes. A few case reports of oral squamous cell carcinomas arising from regions of phenytoin induced gingival overgrowth (GO), and overexpression of mitogenic factors and p53 have presented this condition as a pathology with potential to transform into malignancy. We recently investigated the genetic status of p53 and H-ras, which are known to be frequently mutated in Indian oral carcinomas in GO tissues and found them to only contain wild type sequences, which suggested a non-neoplastic nature of phenytoin induced GO. However, besides p53 and H-ras, other oncogenes and tumor suppressors such as PIK3CA, p14ARF, p16INK4a and p21Waf1/Cip1, are frequently altered in oral squamous cell carcinoma, and hence are required to be analyzed in phenytoin induced GO tissues to be affirmative of its non-neoplastic nature. METHODS: 100ng of chromosomal DNA isolated from twenty gingival overgrowth tissues were amplified with primers for exons 9 and 20 of PIK3CA, exons 1α, 1ß and 2 of p16INK4a and p14ARF, and exon 2 of p21Waf1/Cip1, in independent reactions. PCR amplicons were subsequently gel purified and eluted products were sequenced. RESULTS: Sequencing analysis of the twenty samples of phenytoin induced gingival growth showed no mutations in the analyzed exons of PIK3CA, p14ARF, p16INK4a and p21Waf1/Cip1. CONCLUSION: The present data indicate that the mutational alterations of genes, PIK3CA, p14ARF, p16INK4a and p21Waf1/Cip1 that are frequently mutated in oral squamous cell carcinomas are rare in phenytoin induced gingival growth. Thus the findings provide further evidence that phenytoin induced gingival overgrowth as a non-neoplastic lesion, which may be considered as clinically significant given the fact that the epileptic patients are routinely administered with phenytoin for the rest of their lives to control seizure episodes.

Arthropathy, osteolysis, keloids, relapsing conjunctival pannus and gingival overgrowth: a variant of polyfibromatosis?

Polyfibromatosis is a rare fibrosing condition characterized by fibromatosis in different body areas and by keloid formation, and which can be associated with arthropathy and osteolysis. Familial occurrence has been described, but the cause remains unknown. Here, we describe a patient with characteristics of polyfibromatosis with arthropathy who had in addition severe conjunctival fibrosis, distinctive face, gingival overgrowth, and pigmented keloids. We discuss the resemblances and differences with polyfibromatosis and descriptions of other, similar patients. We conclude that at present it remains uncertain whether the patient has a variant of polyfibromatosis or a separate entity.

Interleukin-10 gene promoter polymorphisms are associated with cyclosporin A-induced gingival overgrowth in renal transplant patients.

OBJECTIVE: Interleukin-10 (IL-10) is an anti-inflammatory cytokine whose genetic polymorphisms are associated with the production of IL-10 and the susceptibility to periodontal diseases. The aim of this study was to investigate the possible association of IL-10 single nucleotide polymorphisms (SNPs) and cyclosporin A (CsA)-induced gingival overgrowth (GO) in renal transplant patients in a Chinese population, taking into account subgingival microbiota as additional variables. MATERIAL AND METHODS: A total of 202 patients were dichotomized into two groups: 122 with GO and 80 without GO. The IL-10-1082 SNP, -819 SNP and -592 SNP were measured using an allele-specific PCR method. The levels of subgingival bacteria were measured by real-time PCR. Genotype and allele frequencies were analyzed using the Chi-square test and logistic regression analysis. RESULTS: The frequency of IL-10-819TT (-592AA) genotype was statistically higher in patients with GO than that in patients without GO (P<0.05). Multiple logistic regression analysis demonstrated that the prevalence of GO is not dependent on age, gender, and pharmacological variables, being significantly associated with the carriers of ATA haplotype (OR=2.425, 95%CI=1.214-4.845, P=0.012). Moreover, ATA positive carriers in the GO group presented significantly higher levels of Porphyromonas gingivalis and Treponema denticola than those negative carriers. CONCLUSIONS: Our results show that IL-10-819TT (-592AA) genotype and ATA halpotype are associated with susceptibility to CsA-induced GO. Meanwhile, ATA haplotype is associated with a higher detection of P. gingivalis and T. denticola in GO patients, and may increase the risk of developing GO.

Effect of periodontal therapy on the course of cyclosporin-induced gingival overgrowth: role of ABCB1 and PAI-1 gene polymorphisms.

OBJECTIVES: Etiological periodontal therapy is effective in reducing cyclosporin A-induced gingival overgrowth, but a high variability among subjects has been observed. This study aimed to evaluate the role of polymorphisms in PAI-1 and A BCB1 genes on the course of this side effect following periodontal therapy. METHOD AND MATERIALS: Forty-five transplant patients were subjected to nonsurgical periodontal therapy and evaluated for hypertrophy index, probing depths, bleeding, and plaque scores at baseline, and after 3 and 6 months. A BCB1 (C3435T and G2677T) and PAI-1 (4G/5G) polymorphisms were studied with polymerase chain reaction-restriction fragment length polymorphism and allele-specific polymerase chain reaction respectively. RESULTS: All the monitored periodontal indexes decreased significantly during the six months. Modeling of hypertrophy index by linearmixed- effect models (allowing non-normal distribution of the outcome variable hypertrophy index) resulted in the selection as the most significant model, of the one comprising the independent variables: time, C 3435T genotype, and their interaction term. This model indicated that C 3435T-mutated patients had significantly higher baseline hypertrophy index values (90% Markov chain Monte C arlo empirical confidence intervals: 5.08, 30.00). The decrease in hypertrophy index values over time showed a trend toward being faster in mutated than nonmutated patients (interaction time: C 3435T nonmutated, 90% Markov chain Monte C arlo empirical confidence interval: -11.08, -0.40). When hypertrophy index values were normalized, the significance and trend were lost. No effect of the A BCB1 G2677T and PAI-1 4G/5G polymorphisms was observed. CONCLUSION: These preliminary results suggest that C 3435T polymorphism is a genetic factor that could influence the course of cyclosporin A-induced gingival overgrowth in transplant patients subjected to periodontal therapy.

Expression of angiotensin II and its receptors in cyclosporine-induced gingival overgrowth.

BACKGROUND AND OBJECTIVES: The renin-angiotensin system (RAS) is considered as a hormonal circulatory system involved in maintaining blood pressure, electrolyte and fluid homeostasis. RAS components can be synthesized in local tissues and are found to play a role in gingival overgrowth. The drug-induced gingival overgrowth (DIGO) is a fibrotic condition, which is associated with multiple factors, including inflammation and adverse drug effects such as cyclosporine A. This study was directed forward to the identification of the angiotensinogen, angiotensin II (Ang II) and its receptors AT1 /AT2 expression in DIGO tissues and cyclosporine-treated human gingival fibroblast cells. MATERIAL AND METHODS: Gingival samples were obtained from patients with cyclosporine-induced gingival overgrowth, chronic periodontitis and normal healthy subjects. The total RNA was isolated and reverse transcription-polymerase chain reaction was performed for angiotensinogen, Ang II and AT1 /AT2 receptor. Ang II protein was estimated from tissue by enzyme immunoassay. The expression of Ang II and its receptors were also examined in gingival fibroblast cells treated with cyclosporine. RESULTS: Ang II mRNA and protein expression was significantly higher in patients with DIGO than in patients with periodontitis and healthy subjects. The AT1 mRNA was expressed more than AT2 in all examined tissues. In gingival fibroblasts, Ang II and AT1 expressions were increased with cyclosporine incorporation compared to controls. CONCLUSION: These results suggest that cyclosporine can modulate local expression of RAS components such as angiotensinogen, Ang II and its receptors in gingival tissues and gingival fibroblast cells.

Tumoral calcinosis: a dental literature review and case report.

UNLABELLED: Tumoral calcinosis (TC) is a rare familial disease characterized by abnormal peri-articular calcification in affected joints, without any associated renal, metabolic or collagen vascular disease. It is characterized by usual hyperphosphataemia with normal serum calcium and alkaline phosphatase values. There are only a few reported cases ofTC patients with dental findings. This article reviews the dental literature and describes progressive gingival, alveolar and mandibular tori enlargement in a 41-year-old female from Zimbabwe with tumoral calcinosis. CLINICAL RELEVANCE: Tumoral calcinosis is a rare disorder of mineral metabolism with oral manifestations.

Lack of mutation in p53 and H-ras genes in phenytoin induced gingival overgrowth suggests its non cancerous nature.

BACKGROUND: There have been case reports of oral squamous cell carcinoma arising from gingival overgrowth induced by phenytoin--an antiepileptic drug. However, a detailed analysis for the presence of mutations in p53 and ras genes, which are the two most frequently mutated genes in cancers, in phenytoin induced gingival overgrowth tissues has hitherto not been performed. METHODS: Cellular DNA isolated from twenty gingival overgrowth tissues collected from patients undergoing phenytoin therapy were amplified using primers for p53 (exons 5-8) and H-ras (exons 1-2) genes. The PCR amplicons were then gel purified and subjected to direct sequencing analysis to screen for mutations. RESULTS: Direct sequencing of twenty samples of phenytoin induced gingival growth did not identify mutations in any of the exons of p53 and H-ras genes that were analyzed. CONCLUSION: Our result indicates that mutational alteration of p53 and H-ras genes is infrequent in phenytoin induced gingival growth, which thus suggests a non malignant nature of this pathology. The findings in the present study are clinically significant as a large number of epileptic patients are treated with phenytoin.

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.