Expression of matrix metalloproteinases (MMP-8 and -9) in chronic periodontitis patients with and without diabetes mellitus.

BACKGROUND: Matrix metalloproteinases (MMPs) are involved in a number of physiological events, and they are the major players in collagen breakdown during periodontal tissue destruction. Diabetes mellitus (DM) has been associated with altered collagen metabolism and increases the response of the periodontal tissue to pathogenic microorganisms, thereby increasing the severity of periodontal disease. The aim of this study was to assess the expression of MMP-8 and -9 in gingival tissues of diabetic chronic periodontitis (CP), non-diabetic CP, and healthy patients.
METHODS: The plaque index (PI), gingival index (GI), probing depth (PD), and clinical attachment level (CAL) were assessed. The levels of MMP expression in gingival tissue extracts were measured by gelatin zymography and Western blotting. The structural changes in tissues were analyzed by histological examination and collagen estimation.
RESULTS: Higher levels of PI, GI, CAL, and deeper PD were observed in CP patients with DM than CP patients without DM. The average concentration of MMP-9 was increased three-fold, and the MMP-8 was increased two-fold in CP patients with DM compared to CP patients without DM. A high infiltration of inflammatory cells and less collagen were observed in the histologic analysis of gingival biopsies from diabetic patients.
CONCLUSIONS: An increased concentration of MMP-8 and -9 in the gingival tissue of diabetic CP patients suggests that the expression of these MMPs contributes to the failure of the healing process in the diabetic condition. Treatment strategies directed toward the inhibition of these MMPs could lead to an improved healing rate in CP patients.