The in vivo Expression of the collagenolytic matrix metalloproteinases (MMP-2,-8,-13, and-14) and matrilysin (MMP-7) in Adult and localized juvenile periodontitis

Periodontal inflammation is characterized by irreversible degradation of pe riodontal ligament collagen fibers leading to loss of tooth attachment. Cul tured gingival keratinocytes and fibroblasts express, in vitro, various mat rix metalloproteinases (MMPs) which can degrade fibrillar collagens. We hyp othesized that several MMPs are also synthesized in vivo by sulcular epithe lium, and analyzed the collagenolytic MMPs (MMP-2, -8, -13, and -14) and ma trilysin (MMP-7) in gingival tissue specimens and gingival crevicular fluid from adult and localized juvenile periodontitis patients by in situ hybrid ization, immunohistochemistry, and Western immunoblotting. MMP-2, -7, -8, a nd -13 were expressed in gingival sulcular epithelium. MMP-7 and -13 were a lso located in fibroblasts and macrophages, and MMP-8 in neutrophils. MMP-8 - and -13-positive cells/mm(2) were higher in periodontitis gingiva when co mpared with healthy control tissue (p < 0.01). In periodontal diseases, gin gival sulcular epithelium expresses several, rather than a single, collagen olytic MMPs, and this proteolytic cascade is evidently responsible for the tissue destruction characteristic of adult and juvenile periodontitis.