The Effect of α‐Tocopherol and Selenium on Human Gingival Fibroblasts and Periodontal Ligament Fibroblasts In Vitro

Background: The aim of the present study is to evaluate the effect of α‐tocopherol and selenium on gingival fibroblasts (GFs) and periodontal ligament fibroblasts (PDLFs) in terms of proliferation, basic fibroblast growth factor (bFGF) release, collagen type I synthesis, and wound healing. Methods: Primary cultures of human GFs and PDLFs were isolated. Four test groups and a control group free of medication was formed. In group E, 60 μM α‐tocopherol was used, and in groups ES1, ES2, and ES3, the combination of 60 μM α‐tocopherol with 5 × 10^?9 M, 10 × 10^?9 M, and 50 × 10^?9 M selenium was used, respectively. Viability, proliferation, bFGF, and collagen type I synthesis from both cell types were evaluated at 24, 48, and 72 hours, and healing was compared on a new wound‐healing model at 12, 24, 36, 48, and 72 hours. Results: α‐Tocopherol alone significantly increased the healing rate of PDLFs at 12 hours and increased bFGF and collagen type I release from GFs and PDLFs at 24, 48, and 72 hours. The α‐tocopherol/selenium combination significantly enhanced the proliferation rate of both cells at 48 hours, decreased the proliferation of PDLFs at 72 hours, and increased the healing rate of GFs at 12 hours and PDLFs at 12 and 48 hours. bFGF and collagen type I synthesis was also increased in both cell types at 24, 48, and 72 hours by α‐tocopherol/selenium combination. Conclusion: α‐Tocopherol and α‐tocopherol/selenium combination is able to accelerate the proliferation rate and wound‐healing process and increase the synthesis of bFGF and collagen type I from both GFs and PDLFs.     

Tumor Necrosis Factor‐α Inhibits Transforming Growth Factor‐β–Stimulated Myofibroblastic Differentiation and Extracellular Matrix Production in Human Gingival Fibroblasts

Background: Fibroblasts play a critical role during wound healing and chronic inflammation through the synthesis and assembly of extracellular matrix (ECM) molecules. These responses may be modulated by soluble cytokines and growth factors present in tissues. In the present study, we evaluate whether transforming growth factor‐β1 (TGF‐β1) and tumor necrosis factor‐α (TNF‐α) modulate myofibroblastic differentiation and the production of ECM components. Methods: Primary cultures of human gingival fibroblasts (HGFs) were stimulated with recombinant TGF‐β1 and TNF‐α. Protein levels of α‐smooth muscle actin (α‐SMA), type I collagen, heat shock protein‐47 (HSP‐47), fibronectin (FN), ED‐A‐FN, and periostin and activation of the Smad pathway were evaluated through Western blot analysis. α‐SMA and actin fibers were identified by immunofluorescence. TGF‐β1, TNF‐α, and α‐SMA were identified by immunohistochemistry in biopsies of inflamed human gingival tissues. TGF‐β1 activity was evaluated using a plasminogen activator inhibitor‐1 (PAI‐1) reporter transfected in HGFs. Results: TGF‐β1 stimulated the differentiation of myofibroblasts as evidenced by strong expression of α‐SMA and ED‐A‐FN. Moreover, TGF‐β1 induced the production of type I collagen, HSP‐47, FN, and periostin. Costimulation with TNF‐α and TGF‐β1 significantly reduced the expression of all the above‐mentioned proteins. TNF‐α also inhibited the activation of the Smad2/3 pathway and the activity of the PAI‐1 reporter. Conclusions: TNF‐α inhibits several cell responses induced by TGF‐β1, including the differentiation of myofibroblasts, the activation of the Smad signaling pathway, and the production of key molecules involved in tissue repair, such as type I collagen, FN, and periostin. The interaction between cytokines may explain the delayed tissue repair observed in chronic inflammation of gingival tissues.     

Evaluation of Recession Defects Treated With Coronally Advanced Flaps and Either Recombinant Human Platelet‐Derived Growth Factor‐BB Plus β‐Tricalcium Phosphate or Connective Tissue: Comparison of Clinical Parameters at 5 Years

Background: In a previously reported split‐mouth, randomized controlled trial, Miller Class II gingival recession defects were treated with either a connective tissue graft (CTG) (control) or recombinant human platelet‐derived growth factor‐BB + β‐tricalcium phosphate (test), both in combination with a coronally advanced flap (CAF). At 6 months, multiple outcome measures were examined. The purpose of the current study is to examine the major efficacy parameters at 5 years. Methods: Twenty of the original 30 patients were available for follow‐up 5 years after the original surgery. Outcomes examined were recession depth, probing depth, clinical attachment level (CAL), height of keratinized tissue (wKT), and percentage of root coverage. Within‐ and across‐treatment group results at 6 months and 5 years were compared with original baseline values. Results: At 5 years, all quantitative parameters for both treatment protocols showed statistically significant improvements over baseline. The primary outcome parameter, change in recession depth at 5 years, demonstrated statistically significant improvements in recession over baseline, although intergroup comparisons favored the control group at both 6 months and 5 years. At 5 years, intergroup comparisons also favored the test group for percentage root coverage and change in wKT, whereas no statistically significant intergroup differences were seen for 100% root coverage and changes to CAL. Conclusions: In the present 5‐year investigation, treatment with either test or control treatments for Miller Class II recession defects appear to lead to stable, clinically effective results, although CTG + CAF resulted in greater reductions in recession, greater percentage of root coverage, and increased wKT.