Background: A major feature of gingivitis and periodontitis is the destruction of the collagenous matrix of the surrounding connective tissue. The hypothesis that proteolytic enzymes release from cells adjacent to the site of destruction was recently supported by the presence of increased levels of cathepsin B, D, and L in the gingival crevicular fluid of patients suffering from periodontal disease (PD).
Experimental design: We studied the expression of mRNA of cathepsins B,D, and L in early passaged, adherent gingival fibroblasts of patients with chronic adult PD. In addition, we examined the presence of cathepsin D and L mRNA-expressing cells in periodontal tissue specimen by in situ hybridization, and we localized the respective enzymes by immunohistochemistry.
Results: Strong gene expression of the three cathepsin types could be detected by dot hybridization in all PD-derived gingival cells. Immunohistochemical distribution of cathepsins and mRNA for cathepsin D and L could be demonstrated mainly in PD tissue specimen, largely in the area in between the epithelium and the adjacent subepithelial connective tissue. Examination of the cell types revealed multiple macrophage- and fibroblast-shaped cells expressing positive staining for cathepsins.
Conclusions: The present data support the the concept that cathepsins play a major role in tissue destruction and may represent a target for therapeutic interventions.