The overexpression of cyclo-oxygenase-2 in chronic periodontitis

Background. The objective of this prospective cross-sectional study was to determine if cyclo-oxygenase-2, or COX-2, is overexpressed in the inflamed gingival tissue of patients diagnosed as having moderate-to-severe chronic periodontitis, or CP. Methods. The authors evaluated clinical measures, crevicular fluid and gingival biopsy specimens from patients with moderate or severe CP (n = 16) and from healthy volunteers (n = 8). Patients were diagnosed as having CP based on clinical attachment loss, or CAL, of at least 5 millimeters at two sites in each quadrant and on evidence of alveolar bone loss as assessed from standard periapical or bite-wing radiographs. Healthy patients exhibited no sites with CAL of more than 2 mm and no evidence of alveolar bone loss. The authors used standard techniques to perform biochemical measures. Results. Levels of interleukin-1 beta, or IL-1β, in crevicular fluid were more than doubled in the CP group (P < .05). The amounts of COX-2 mRNA and protein also were elevated in gingival tissues from subjects with CP compared with those from healthy subjects. To gain further mechanistic insights, the authors conducted in vitro studies. The results showed that lipopolysaccharide and tumor necrosis factor alpha, or TNF-α, induced COX-2 in macrophages, while IL-1β and TNF-α induced COX-2 in oral epithelial cells. Conclusions. Taken together, these results suggest that levels of COX-2 in gingivae reflect clinical measures of periodontitis and gingival inflammation. Clinical Implications. The discovery of increased levels of COX-2 in inflamed gingival tissue suggests that COX-2 represents a pharmacological target for the prevention or treatment of CP.