Immunohistochemical characterization of lymphocyte subsets in chronic adult periodontitis

Expression of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in healthy and diseased human gingiva

BACKGROUND

The purpose of this study was to quantify the amount of matrix metalloproteinases such as MMP-1, MMP-2, MMP-3, MMP-7, MMP-9, and MMP-13 and tissue inhibitors of metalloproteinases TIMP-1 and TIMP-2 expressed by human gingival explants in culture media and the area fraction (AA%) of gingival collagen fibers according to the degree of inflammation, to investigate a possible correlation between these enzymes and collagen loss.

METHODS

Gingival tissue specimens from 6 healthy controls (group 1), 17 patients with mild gingival inflammation (group 2), 10 patients with moderate gingival inflammation (group 3), and 9 patients with severe gingival inflammation (group 4) were placed in organ culture for 3 days. The MMPs and TIMPs in the culture media were quantified using zymography, dot blotting, and Western blotting. Paraffin gingival sections were stained with sirius red F3Ba for visualization of collagen fibers, then the area fraction (AA%) occupied by the gingival fibers was determined by automated image analysis.

RESULTS

The AA% occupied by collagen fibers significantly decreased from group 1 (53%) to group 4 (35%). The decrease in collagen fibers was inversely correlated with the significant increase in MMP-1, MMP-9, and MMP-13 (dot blotting analysis), with the increase of the active form of MMP-2, and with the active form and proform of MMP-9 (zymography analysis).

CONCLUSION

The present study showed that metalloproteinases, particularly MMP-2, MMP-9, MMP-1, and MMP-13, are involved in the gingival extracellular matrix degradation during periodontitis.

Is collagen breakdown during periodontitis linked to inflammatory cells and expression of matrix metalloproteinases and tissue inhibitors of metalloproteinases in human gingival tissue?

BACKGROUND

Evidence of the role of matrix metalloproteinases (MMPs) produced by resident and inflammatory cells in periodontal destruction is now well established. The purpose of this study was to quantify, in healthy and diseased upper gingival connective tissue, the area fraction (AA%) occupied by collagen fibers, the cell number belonging to inflammatory cell subsets, and the amounts of MMPs and TIMPs (tissue inhibitors of MMPs) in order to investigate the possible correlations, if any, between such molecules, collagen loss, and inflammatory cell subsets.

METHODS

Gingival tissue specimens from 6 healthy controls (C) and 6 patients with severe periodontitis (P) were divided into 2 groups. The first group of specimens was frozen and used for the staining of collagen fibers by sirius red F3Ba and for immunohistochemistry with antibodies against CD8, CD4, CD22, CD68, and TIA-1 molecules. The second group was used for organ culture, zymography, Western blotting, and dot blotting. Morphometric and automated image analysis was performed for the evaluation of the area fraction occupied by collagen fibers, the number of inflammatory cell subsets and for enzymatic activities developed by MMPs, and the amounts of TIMPs expressed during periodontal disease.

RESULTS

In group P, the area fraction of collagen fibers (33 +/- 10%) was significantly decreased (P < 0.0002) when compared to group C (60 +/- 7%), and was correlated with the number of all inflammatory cells and amounts of MMPs and TIMPs. In group P, there were significant increases of CD8+, CD22+, CD68+, and TIA-1+ cells, as well as increases in the amounts of MMP-1, MMP-2, MMP-3, MMP-9, and the active form of MMP-9. The active form of MMP-9 and the amount of TIMP-1 were positively correlated with the number of CD22+, CD68+, and TIA-1+ cells.

CONCLUSIONS

The present study showed an imbalance between MMPs and TIMPs associated with the pathologic breakdown of the extracellular matrix during periodontitis. The active form of MMP-9 could be a marker for the clinical severity of periodontal disease.

Production of Rantes/CCL5 in human gingival fibroblasts challenged with tumor necrosis factor alpha

Chemokines are small-secreted proteins that stimulate the directional migration of leukocytes and thereby mediate the inflammatory process. The present study investigates the capacity of human gingival fibroblasts to produce the beta chemokine Rantes/CCL5. In situ hybridization, immunohistochemistry and ELISA were used to measure the induction of Rantes/CCL5 at the mRNA and protein levels, both in unstimulated gingival fibroblasts as well as in fibroblasts treated with the proinflammatory cytokines tumor necrosis factor (TNF)alpha or interleukin (IL)-1beta. TNFalpha in different concentrations (0.1-10 ng/ml) induced Rantes/CCL5 mRNA expression and protein production in 24-h cultures of human gingival fibroblasts. The expression of Rantes/CCL5-mRNA and protein production, induced by TNFalpha, was evident at 6 h and thereafter increased continuously during the study period (24 h). IL-1beta (3-300 pg/ml) also enhanced the production of Rantes/CCL5 in gingival fibroblasts. The amount of Rantes/CCL5 induced by IL-1beta (300 pg/ml), however, was less than that induced by TNFalpha (10 ng/ml). The study suggests that human gingival fibroblasts, by producing the chemokine Rantes/CCL5, participate in the regulation of the host response during the inflammatory process in the periodontal tissue.