Human gingival tissues in culture synthesize three metalloproteinases and a metalloproteinase inhibitor

Explants of human gingiva obtained during periodontal surgery and maintained in tissue culture synthesized three metalloproteinases which degraded collagen, gelatin, and proteoglycan respectively. Collagenase and gelatinase were present in both active and latent forms suggesting that collagen degradation was taking place. Proteoglycan degrading activity, however, was present only in the latent form.
Human gingival fibroblasts in monolayer culture did not synthesize metalloproteinases, but did produce an inhibitor with properties similar to the purified inhibitor TIMP (Tissue Inhibitor of Metallo-Proteinases) synthesized by rabbit bones in culture. Human gingival fibroblast inhibitor had an apparent molecular weight of 32,000 on gel filtration and blocked the activity of all three metalloproteinases.
These findings indicate that further investigation of the factors that control or modify metalloproteinase and TIMP activity in gingival tissues should help clarify the pathogenic mechanisms responsible for connective tissue loss in periodontal disease.