PUB - Publikationen an der Universität Bielefeld

Dental plaque is the major aetiological factor in periodontal diseases and contains several proteolytic enzymes. The origin of these proteinases is, however, poorly studied. This study was undertaken to characterize collagenase present in dental plaque of adult periodontitis patients. Vertebrate-type rather than bacterial-derived collagenase activity was detected in extracts of both supra- and subgingival dental plaque extracts of adult periodontitis patients. Dental plaque collagenase was found to exist predominantly in autoactive form. Dental plaque collagenase from periodontally healthy individuals existed in latent form. Latent dental plaque collagenase from periodontitis lesions could be activated by a 95 kD chymotrypsin-like proteinase from Treponema denticola and human leukocyte cathepsin G but not by human plasmin. Incubation of purified latent leukocyte collagenase with whole cells of Fusobacterium nucleatum, Eubacterium saburreum, Prevotella buccae and Porphyromonas gingivalis, however, did not result to the activation of the enzyme. Doxycycline in vitro inhibited dental plaque collagenase with an IC50-value of 20 mu M. Dental plaque collagenase degraded more efficiently type I and II collagens than type III collagen. Western-blot analysis with specific anti-human neutrophil collagenase-antibody revealed that both in supra-and subgingival dental plaque extracts dental plaque collagenase had undergone proteolytic conversion from an 80 kD preform to a 58 kD active form which is associated with catalytic autoactivity as measured by functional collagenase assay. This reflects proteolytic activation of leukocyte collagenase in dental plaque probably by other proteases derived from potent periodontopathogenic bacteria such as T. denticola or other PMN proteases such as cathepsin G. Multiple different molecular weight gelatinases (20-200 kD) including fragmented low molecular weight human neutrophil 92 kD gelatinase species were detected in both supra- and subgingival dental plaque extracts. Leukocyte collagenase, previously found to be the main type of collagenase present in adult periodontitis gingiva, gingiva crevicular fluid and saliva, is also the predominant type of collagenase in the plaque of periodontitis patients. Fragmented but catalytically active neutrophil gelatinase species are also present in dental plaque. The dental plaque has potential to serve as a reservoir and site of activation of neutrophil (PMN)-derived matrix metalloproteinases in the periodontal inflammation.