The nonantimicrobial properties of tetracycline for the treatment of periodontal disease.

Tetracyclines have nonantimicrobial properties that appear to modulate host response. In that regard, tetracyclines and their nonantimicrobial chemically modified analogues (chemically modified tetracycline molecules [CMTs]) inhibit the extracellular activity of mammalian neutrophil and osteoblast collagenases. The activity of this matrix metalloproteinase appears crucial in the destruction of collagen. Apart from its anticollagenase effect, tetracyclines are also potent inhibitors of osteoclast function. Several recent studies have also addressed the therapeutic potential of tetracyclines and CMTs in periodontal disease. These drugs reduced excessive gingival collagenase activity and severity of periodontal breakdown in rats infected with Porphyromonas gingivalis and in diabetic rats. CMT was not associated with the emergence of resistant microorganisms. In human double-blind clinical trials, low-dose doxycycline therapy substantially reduced collagenase activity in the gingival and crevicular fluid, and prevented the loss of attachment in adult periodontitis without the emergence of doxycycline-resistant microorganisms. Tetracyclines and CMTs have enormous therapeutic potential because these drugs can inhibit the activity of matrix metalloproteinases as well as osteoclast function, and thus prevent the degradation of osseous connective tissues in periodontal as well as arthritic diseases.