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 gingi-val 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 patho-genetic 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.