Myofibroblasts and mast cells: influences on biological behavior of odontogenic lesions.

Odontogenic lesions differ in their rate of recurrence and aggressiveness. This study aimed to evaluate the presence of myofibroblasts and mast cells in odontogenic lesions. Sample consisted of 20 cases each of dentigerous cysts, odontogenic keratocysts, and solid ameloblastomas. Histologic sections were submitted to immunohistochemistry using anti-α-smooth muscle actin and anti-tryptase antibodies. Myofibroblasts and mast cells were counted at ×400 magnification in 5 and 10 fields, respectively. Myofibroblasts were more frequent in ameloblastomas (24.41), followed by odontogenic keratocysts (16.21) and dentigerous cysts (11.85; P=.002). Granulated and degranulated mast cells were more frequent in dentigerous cysts (7.88 and 8.96, respectively), followed by odontogenic keratocysts (6.53 and 7.08) and ameloblastomas (5.21 and 1.88). The difference was only significant for degranulated mast cells (P<.05). Analysis of the correlation between myofibroblasts and mast cells (granulated and degranulated) revealed a moderate positive correlation only in ameloblastomas (R=0.621, P=.003). Probably, myofibroblasts are related to the biological behavior of the odontogenic lesions studied, particularly their aggressiveness. On the other hand, mast cells seem to be associated with inflammatory processes, which are more frequent in cystic lesions than in benign neoplasms. In addition, mast cells may induce the differentiation of fibroblasts into myofibroblasts, thus increasing the number of the latter.

Study of the participation of MMP-7, EMMPRIN and cyclophilin A in the pathogenesis of periodontal disease.

BACKGROUND AND OBJECTIVE: Periodontal disease is an infectious disease resulting from the immunoinflammatory response of the host to microorganisms present in the dental biofilm which causes tissue destruction. The objective of this study was to evaluate the immunohistochemical expression of matrix metalloproteinase 7 (MMP-7), extracellular matrix metalloproteinase inducer (EMMPRIN) and cyclophilin A (CypA) in periodontal disease. DESIGN: Gingival tissue samples were divided as follows: clinically healthy gingiva (n=32), biofilm-induced gingivitis (n=28), and chronic periodontitis (n=30). Histological sections of 3µm were submitted to immunoperoxidase method and undergone quantitative analysis. The results were analyzed statistically by the Mann-Whitney and Spearman correlation tests, with the level of significance set at 0.05 (α=0.05). RESULTS: Immunopositivity for MMP-7, EMMPRIN and CypA differed significantly between the three groups, with higher percentages of staining in chronic periodontitis specimens, followed by chronic gingivitis and healthy gingiva specimens (p<0.05). Immunoexpression of CypA and MMP-7 was higher in the intense inflammatory infiltrate observed mainly in cases of periodontitis (p<0.05). CypA expression was positively correlated with MMP-7 (r=0.831; p<0.001) and EMMPRIN (r=0.289; p=0.006). In addition, there was a significant positive correlation between probing depth and expression of MMP-7 (r=0.726; p<0.001), EMMPRIN (r=0.345; p=0.001), and CypA (r=0.803; p<0.001). CONCLUSION: These results suggest that MMP-7, EMMPRIN and CypA are associated with the pathogenesis and progression of periodontal disease.