Cyclooxygenase-2 and matrix metalloproteinase-9 expressions correlate with tissue inflammation degree in periodontal disease.

Cyclooxygenase-2 (Cox-2) and matrix metalloproteinase-9 (MMP-9) have synergistic effects in the degradation of the extra-cellular matrix.The aim of our study was to correlate the intensity of inflammation with MMP-9 and Cox-2 expression in the periodontal tissue of patients with chronic inflammatory disease (gingivitis and chronic periodontitis) in order to determine the role of these two biomarkers in the progression of periodontal disease.To conduct this study we analyzed the gingival biopsies taken from patients clinically divided into three study groups: Group I (control): Patients free of periodontal disease (seven biopsies); Group II: Patients with gingivitis (10 biopsies); Group III: Patients with chronic periodontitis (10 biopsies). In these three groups, we graded the intensity of inflammation in the lamina propria and the immunohistochemical expression of MMP-9 and Cox-2.The presence of a large number of inflammatory cells in the lamina propria in patients with gingivitis or chronic periodontitis (Groups II and III) correlated with the clinically diagnosed inflammation of the gingival tissue. The expression of MMP-9 was higher in patients with chronic periodontitis than in those with gingivitis, showing a trend towards statistical significance (p=0.07, Mann-Whitney U-test). The expression of Cox-2 in periodontitis was also higher compared to gingivitis (p=0.05, Mann-Whitney U-test) and to controls (p=0.001, Mann-Whitney U-test).The inflammation score could be positively correlated to the MMP-9 and Cox-2 expression scores at the overall study group, but not separately on gingivitis and periodontitis patients.The presence of an intensive inflammatory infiltrate is characteristic both for periodontitis and gingivitis. MMP-9 and Cox-2 show higher expression in periodontitis, than in gingivitis and healthy controls, but MMP-9 and Cox-2 expression scores cannot be directly correlated to the grade of inflammatory infiltrate in the two different disease entities. As biomarkers of chronic inflammation activity, angiogenesis, and degradation of the extracellular matrix, MMP-9 and Cox-2 can be used in clinical practice for the detection of patients with chronic periodontitis risk, at whom treatment with Cox-2 and MMP-9 inhibitors may be considered.