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

Genetic Variants in the TBC1D2B Gene Are Associated with Ramon Syndrome and Hereditary Gingival Fibromatosis

Ramon syndrome (MIM 266270) is an extremely rare genetic syndrome, characterized by gingival fibromatosis, cherubism-like lesions, epilepsy, intellectual disability, hypertrichosis, short stature, juvenile rheumatoid arthritis, and ocular abnormalities. Hereditary or non-syndromic gingival fibromatosis (HGF) is also rare and considered to represent a heterogeneous group of disorders characterized by benign, slowly progressive, non-inflammatory gingival overgrowth. To date, two genes, ELMO2 and TBC1D2B, have been linked to Ramon syndrome. The objective of this study was to further investigate the genetic variants associated with Ramon syndrome as well as HGF. Clinical, radiographic, histological, and immunohistochemical examinations were performed on affected individuals. Exome sequencing identified rare variants in TBC1D2B in both conditions: a novel homozygous variant (c.1879_1880del, p.Glu627LysfsTer61) in a Thai patient with Ramon syndrome and a rare heterozygous variant (c.2471A>G, p.Tyr824Cys) in a Cambodian family with HGF. A novel variant (c.892C>T, p.Arg298Cys) in KREMEN2 was also identified in the individuals with HGF. With support from mutant protein modeling, our data suggest that TBC1D2B variants contribute to both Ramon syndrome and HGF, although variants in additional genes might also contribute to the pathogenesis of HGF.

Biology of Drug-Induced Gingival Hyperplasia: In Vitro Study of the Effect of Nifedipine on Human Fibroblasts

Background: It has been proven that the antihypertensive agent nifedipine can cause gingival overgrowth as a side effect. The aim of this study was to analyze the effects of pharmacological treatment with nifedipine on human gingival fibroblasts activity, investigating the possible pathogenetic mechanisms that lead to the onset of gingival enlargement. Methods: The expression profile of 57 genes belonging to the “Extracellular Matrix and Adhesion Molecules” pathway, fibroblasts’ viability at different drug concentrations, and E-cadherin levels in treated fibroblasts were assessed using real-time Polymerase Chain Reaction, PrestoBlue™ cell viability test, and an enzyme-linked immunoassay (ELISA), respectively. Results: Metalloproteinase 24 and 8 (MMP24, MMP8) showed significant upregulation in treated cells with respect to the control group, and cell adhesion gene CDH1 (E-cadherin) levels were recorded as increased in treated fibroblasts using both real-time PCR and ELISA. Downregulation was observed for transmembrane receptors ITGA6 and ITGB4, the basement membrane constituent LAMA1 and LAMB1, and the extracellular matrix protease MMP11, MMP16, and MMP26. Conclusions: The obtained data suggested that the pathogenesis of nifedipine-induced gingival overgrowth is characterized by an excessive accumulation of collagen due to the inhibition of collagen intracellular and extracellular degradation pathways.

Drug-Induced Gingival Overgrowth: The Effect of Cyclosporin A and Mycophenolate Mophetil on Human Gingival Fibroblasts

Drug-induced gingival overgrowth may occur after a chronic administration of three classes of systemic drugs: Anticonvulsants, immunosuppressants, and calcium channel blockers. This study aimed to investigate how cyclosporin A and mycophenolate mophetil (immunosuppressive drugs) could interfere with human gingival fibroblasts functions, leading to gingival enlargement. Human gingival fibroblasts derived from the tissue of a 60-year-old female were cultured in a DMEME medium. A stock solution with 1 mg/mL of mycophenolate and 1 mg/mL of cyclosporine were prepared and dissolved in a DMEM medium to prepare a serial dilution at the concentrations of 5000, 2000, 1000, 500, and 100 ng/mL, for both treatments. Cell viability was measured using the PrestoBlue™ Reagent Protocol. Quantitative real-time RT-PCR was performed in order to analyze the expression of 57 genes coding for gingival fibroblasts "Extracellular Matrix and Adhesion Molecules". Mycophenolate and cyclosporine had no effect on fibroblast cell viability at 1000 ng/mL. Both the treatments showed similar effects on the expression profiling of treated cells: Downregulation of most extracellular matrix metalloproteases genes (MMP8, MMP11, MMP15, MMP16, MMP24) was assessed, while CDH1, ITGA2, ITGA7, LAMB3, MMP12, and MMP13 were recorded to be upregulated in fibroblasts treated with immunosuppressive drugs. It has been demonstrated that gingival overgrowth can be caused by the chronic administration of cyclosporin A and mycophenolate mophetil. However, given the contrasting data of literature, further investigations are needed, making clear the possible effects of immunosuppressive drugs on fibroblasts.

Nizam MN, Alshammari A. An Update on the Mechanisms of Phenytoin Induced Gingival Overgrowth

Background:

Phenytoin induced gingival overgrowth, a side effect with multifactorial aetiology, is characterized by an increase in the volume of extracellular tissues, particularly collagenous components, with varying degrees of inflammation.

Objective:

The aim of this paper is to review the available literature regarding the pathophysiological mechanisms of phenytoin induced gingival overgrowth.

Methods:

A thorough literature search of the PubMed/ Embase/ Web of science/ Cochrane central database was conducted to identify the mechanisms involved in the process of phenytoin-induced gingival overgrowth using the following keywords: Phenytoin; Anticonvulsant; Gingival Overgrowth; Gingival Enlargement, Gingival Hyperplasia; Drug Induced Gingival Enlargement; Drug Induced Gingival Overgrowth

Results:

According to the available evidence, several mechanisms have been proposed addressing the pathophysiological mechanism of phenytoin induced gingival overgrowth both at a cellular and molecular level. Evidence suggests that the inflammatory changes in the gingival tissues orchestrate the interaction between phenytoin and fibroblasts particularly resulting in an increase in the extracellular matrix content.

Conclusion:

However, the mechanism of production of inflammatory mediators is not fully understood. This, together with the high prevalence of Phenytoin induced gingival overgrowth, warrants further research in this area in order to develop treatment and preventive strategies for the management of this condition.