Drug-Induced Gingival Overgrowth—Molecular Aspects of Drug Actions

Areca nut-induced oral fibrosis - Reassessing the biology of oral submucous fibrosis

BACKGROUND

Oral submucous fibrosis (OSF) is a pathological condition characterized by excessive tissue healing resulting from physical, chemical, or mechanical trauma. Notably, areca nut consumption significantly contributes to the development of oral fibrosis. The current definition of OSF, recognizing its potential for malignant transformation, necessitates a more comprehensive understanding of its pathophysiology and etiology.

HIGHLIGHTS

Areca nut induces fibrotic pathways by upregulating inflammatory cytokines such as TGF-β and expressing additional cytokines. Moreover, it triggers the conversion of fibroblasts to myofibroblasts, characterized by α-SMA and γSMA expression, resulting in accelerated collagen production. Arecoline, a component of areca nut, has been shown to elevate levels of reactive oxygen species, upregulate the expression of various cytokines, and activate specific signaling pathways (MEK, COX2, PI3K), all contributing to fibrosis. Therefore, we propose redefining OSF as "Areca nut-induced oral fibrosis" (AIOF) to align with current epistemology, emphasizing its distinctive association with areca nut consumption. The refined definition enhances our ability to develop targeted interventions, thus contributing to more effective prevention and treatment strategies for oral submucous fibrosis worldwide.

CONCLUSION

Arecoline plays a crucial role as a mediator in fibrosis development, contributing to extracellular matrix accumulation in OSF. The re-evaluation of OSF as AIOF offers a more accurate representation of the condition. This nuanced perspective is essential for distinguishing AIOF from other forms of oral fibrosis and advancing our understanding of the disease's pathophysiology.

Drug induced gingival enlargement - phenytoin: an overview and case report

Gingival enlargement is a side effect of several different medication, including immunosuppressants, anticonvulsants, and calcium channel blockers. It is an inflammatory response that starts when plaque and calculus build up on the tooth surface. The most prevalent long-term neurological condition affecting people is epilepsy. In affluent nations, the prevalence of epilepsy is ~ 1%, whereas in less developed countries, it may >2%. The preferred medication for the condition, phenytoin, has major side effects include gingival enlargement. In addition to being visually disfiguring, this enlargement frequently affects speech, chewing and eating. Furthermore, those with poor dental hygiene, causes disabilities with motor coordination and muscular limitations leading to mental disability and physical impairments are more prone to periodontal disease. This article enlightened the mechanism of drug induced gingival enlargement clinically, microbiologically, and surgically.

The yes-associated protein-1 (YAP1) inhibitor celastrol suppresses the ability of transforming growth factor β to activate human gingival fibroblasts

OBJECTIVE

To determine whether celastrol, an inhibitor of the mechanosensitive transcriptional cofactor yes-associated protein-1 (YAP1), impairs the ability of TGFβ1 to stimulate fibrogenic activity in human gingival fibroblast cell line.

DESIGN

Human gingival fibroblasts were pre-treated with celastrol or DMSO followed by stimulation with or without TGFβ1 (4 ng/ml). We then utilized bulk RNA sequencing (RNAseq), real-time polymerase chain reaction (RT-PCR), Western blot, immunofluorescence, cell proliferation assays to determine if celastrol impaired TGFβ1-induced responses in a human gingival fibroblast cell line.

RESULTS

Celastrol impaired the ability of TGFβ1 to induce expression of the profibrotic marker and mediator CCN2. Bulk RNAseq analysis of gingival fibroblasts treated with TGFβ1, in the presence or absence of celastrol, revealed that celastrol impaired the ability of TGFβ1 to induce mRNA expression of genes within extracellular matrix, wound healing, focal adhesion and cytokine/Wnt signaling clusters. RT-PCR analysis of extracted RNAs confirmed that celastrol antagonized the ability of TGFβ1 to induce expression of genes anticipated to contribute to fibrotic responses. Celastrol also reduced gingival fibroblast proliferation, and YAP1 nuclear localization in response to TGFβ1.

CONCLUSION

YAP1 inhibitors such as celastrol could be used to impair pro-fibrotic responses to TGFβ1 in human gingival fibroblasts.

Nifedipine-Influenced Enlargement of the Masticatory Mucosa in an Elderly Edentulous Patient: A Rare Case Report with a Two-Year Follow-Up

Drug-influenced gingival enlargement is a common side effect associated with certain medications, particularly calcium channel blockers like nifedipine, which has been extensively documented. However, the occurrence of nifedipine-influenced masticatory mucosa overgrowth in edentulous patients is rare. Here, we present a case of nifedipine-influenced mucosal enlargement persisting in a 67-year-old edentulous patient 3 months after the extraction of all his teeth. The patient underwent flap surgery and alveoloplasty to excise the overgrown tissue, followed by complete denture restoration. The antihypertensive medication was replaced with valsartan. A 2-year follow-up revealed no recurrence of overgrowth, indicating the effectiveness of this management strategy for such clinical situation.

Impact of TRP Channels on Extracellular Matrix Remodeling: Focus on TRPV4 and Collagen

Disturbed remodeling of the extracellular matrix (ECM) is frequently observed in several high-prevalence pathologies that include fibrotic diseases of organs such as the heart, lung, periodontium, liver, and the stiffening of the ECM surrounding invasive cancers. In many of these lesions, matrix remodeling mediated by fibroblasts is dysregulated, in part by alterations to the regulatory and effector systems that synthesize and degrade collagen, and by alterations to the functions of the integrin-based adhesions that normally mediate mechanical remodeling of collagen fibrils. Cell-matrix adhesions containing collagen-binding integrins are enriched with regulatory and effector systems that initiate localized remodeling of pericellular collagen fibrils to maintain ECM homeostasis. A large cadre of regulatory molecules is enriched in cell-matrix adhesions that affect ECM remodeling through synthesis, degradation, and contraction of collagen fibrils. One of these regulatory molecules is Transient Receptor Potential Vanilloid-type 4 (TRPV4), a mechanically sensitive, Ca2+-permeable plasma membrane channel that regulates collagen remodeling. The gating of Ca2+ across the plasma membrane by TRPV4 and the consequent generation of intracellular Ca2+ signals affect several processes that determine the structural and mechanical properties of collagen-rich ECM. These processes include the synthesis of new collagen fibrils, tractional remodeling by contractile forces, and collagenolysis. While the specific mechanisms by which TRPV4 contributes to matrix remodeling are not well-defined, it is known that TRPV4 is activated by mechanical forces transmitted through collagen adhesion receptors. Here, we consider how TRPV4 expression and function contribute to physiological and pathological collagen remodeling and are associated with collagen adhesions. Over the long-term, an improved understanding of how TRPV4 regulates collagen remodeling could pave the way for new approaches to manage fibrotic lesions.

Epithelial-to-mesenchymal transition, inflammation, subsequent collagen production, and reduced proteinase expression cooperatively contribute to cyclosporin-A-induced gingival overgrowth development

Drug-induced gingival overgrowth (DIGO), induced by certain immunosuppressive drugs, antihypertensive agents, and antiepileptic drugs, may contribute to the formation of deeper periodontal pockets and intractableness in periodontitis. To date, multiple factors such as enhanced matrix production, inflammation, and reduced matrix degradation might be involved in the pathogenesis of DIGO. We have previously reported that SPOCK-1, a heparan sulfate proteoglycan, could affect gingival thickening by promoting epithelial-to-mesenchymal transition (EMT) in gingival keratinocytes. However, few studies have investigated whether a combination of these factors enhances the DIGO phenotype in animal models. Therefore, we investigated whether SPOCK-1, periodontal inflammation, and cyclosporin-A (CsA) could cooperatively promote gingival overgrowth. We first confirmed that Spock-1 overexpressing (Spock1-Tg) mice showed significantly thicker gingiva and greater alveolar bone loss than WT mice in response to ligature-induced experimental periodontitis. DIGO was induced by the combination of CsA administration and experimental periodontitis was significantly enhanced in Spock1-Tg mice compared to that in WT mice. Ligature-induced alveolar bone loss in CsA-treated Spock1-Tg mice was also significantly greater than that in CsA-treated WT mice, while being accompanied by an increase in Rankl and Col1a1 levels and a reduction in matrix metalloprotease expression. Lastly, SPOCK-1 promoted RANKL-induced osteoclast differentiation in both human peripheral blood mononuclear cells and murine macrophages, while peritoneal macrophages from Spock1-Tg mice showed less TNFα and IL-1β secretion than WT mice in response to Escherichia coli lipopolysaccharide. These results suggest that EMT, periodontal inflammation, and subsequent enhanced collagen production and reduced proteinase production contribute to CsA-induced DIGO pathogenesis.

New Trends in Pathology: From Cell Morphology to Molecular Medicine

After Rudolf Virchow's pioneering works, technological advances boosted the scientific interest in this research field, which nowadays is still far from extinguished [...].

Cyclosporine-Induced Gingival Hyperplasia in a Patient With Lichen Planopilaris: Misfortunes Never Come Singly!

Cyclosporine A constitutes an immunosuppressive medication administered against various autoimmune and autoinflammatory disorders as well as against graft versus host disease. Its most well-known oral adverse effect is gingival hyperplasia. The aim of this study is to report a persistent case of a patient with lichen planopilaris with alopecia treated with cyclosporine leading to the manifestation of gingival hypertrophy. A female patient aged 38 years old was referred to the Department of Oral Medicine/Pathology, Dental School, Aristotle University of Thessaloniki, Greece complaining about gum bleeding, halitosis, and a persistent gingival enlargement, which appeared two months ago. According to her medical history, lichen planopilaris was diagnosed six months ago and was initially treated for 40 days with methylprednisolone 16 mg twice per day without improvement, and was replaced by cyclosporine A 200 mg per day. The clinical oral examination revealed gingival enlargement at areas #34-43, 22-23, and 25-27 without any lesion of lichen planus. The level of oral hygiene was satisfactory, with a limited amount of tartar and plaque. Bleeding on probing was also noticed, and pseudopockets of 5 mm were observed. The serum levels of cyclosporine were 473,60 μg/L, with a normal range, regarding repercussions in the oral cavity, up to 200 μg/L. A decrease of cyclosporine dosage to 150 mg was performed. After 15 days, the clinical appearance significantly improved, and a biopsy was done. The microscopic findings showed mild ulceration and inflammatory infiltrates, together with the abundant presence of collagen stroma, without any sign of malignancy. According to the literature, the high dosage of cyclosporine, its relevant high serum levels, and the presence of plaque were responsible for the manifestation of gingival hypertrophy.