Search

Background: Although abnormal cell proliferation and apoptosis are associated with the pathogenesis of oral lichen planus (OLP), the exactly mechanism of which is not yet known. It has been reported that glutamine (Gln) can promote cell proliferation and inhibit apoptosis of various tumor cells. This study aims to evaluate the effect of Gln metabolism on the balance of proliferation and apoptosis in epithelial cells of OLP. Methods: Thirty human OLP specimens and 11 normal controls were stained by immunohistochemistry to detect the levels of proliferation and Gln metabolism related proteins. Then, the critical role of Gln in cell proliferation and apoptosis was determined by Gln deprivation or treatment with glutaminase inhibitor (CB‐839) to intervene Gln metabolism in human gingival epithelial cells. Cell proliferation was detected using CCK8, p‐mTOR and p‐S6 proteins were detected using Western Blot, cell apoptosis and cell cycle were detected using flow cytometry, and cell stress was detected using immunofluorescence. Results: Compared with normal controls, OLP specimens showed higher levels of Ki‐67 and Gln metabolism‐related proteins, including Gln transporter (ASCT2), glutaminase (GLS), and pathway proteins (p‐mTOR and p‐S6). In vitro, Gln promoted cell proliferation and simultaneously upregulated the activity of mTOR/S6 pathway. Moreover, rapamycin, an mTOR pathway inhibitor, could effectively block the Gln‐induced cell proliferation. MHY1485, an mTOR pathway agonist, could effectively reverse the decline of cell proliferation under Gln deprivation. In addition, inhibiting Gln metabolism caused the accumulation of intracellular radical oxygen species (ROS) and induced cell apoptosis. However, N‐acetylcysteine reversed this state and then decreased cell apoptosis by eliminating intracellular ROS. Conclusion: Gln metabolism is essential to maintain the balance of proliferation and apoptosis in oral epithelial cells, and inhibition of Gln metabolism may have a beneficial effect on OLP treatment. [ABSTRACT FROM AUTHOR]

Background: Symptomatic oral lichen planus is a common chronic T‐cell‐mediated disorder characterized by pain and inflammation. The meta‐analysis aimed to compare and evaluate the effects and safety of tacrolimus for treating patients with symptomatic oral lichen planus. Methods: A comprehensive literature review was performed, including PubMed, the Cochrane Library, Embase, and Web of Science published up to and including December 2020. ClinicalTrials.gov was searched for ongoing trials. There were no restrictions on language or date of publication. Using the Cochrane Collaboration tool, we assessed the risk of bias for randomized controlled trials and estimated the proportion of between‐trial heterogeneity. Results: A total of 9 RCTs evaluating the effects of tacrolimus were included in this study. The results revealed no significant difference in clinical resolution and relapse between tacrolimus and corticosteroids. However, tacrolimus may be more likely to cause mild adverse effects. In particular, clinical resolution was not significantly different between tacrolimus and clobetasol propionate, and between tacrolimus and triamcinolone acetonide, while tacrolimus was more likely to cause adverse effects than triamcinolone acetonide and clobetasol propionate. Moreover, there was no significant difference in pain resolution between tacrolimus and clobetasol. Furthermore, adverse effects were not significantly different between tacrolimus and pimecrolimus. Conclusions: This systematic review and meta‐analysis of 9 clinical trials supported the short‐term application of tacrolimus as an effective regimen in OLP patients resistant to other topical and systemic therapies. Furthermore, the adverse effects of tacrolimus were minor and transient and did not affect tacrolimus' continued application. [ABSTRACT FROM AUTHOR]