Salivary matrix metalloproteinase (MMP-8) levels and gelatinase (MMP-9) activities in patients with type 2 diabetes mellitus

We studied the salivary levels and activities of the matrix metalloproteina ses (MMP)-8 and -9 in 45 type 2 diabetic patients and 77 control subjects. The patients' mean glycosylated haemoglobin (HbA(1c)) was 8.7%, indicating an unsatisfactory metabolic control of the disease. The MMP levels were fur ther related to the clinical and microbiological periodontal findings as we ll as to salivary flow rate and other factors. The salivary flow rate, albu min and amylase concentrations were similar in type 2 diabetic patients to those in the control group. The mean gingival and periodontal pocket indexe s were higher in the diabetes group. The number of potential periodontopath ogenic bacteria was lower, however, in the diabetic than in the control gro up. Zymography and immunoblotting revealed that the major MMPs in the type 2 diabetic patients' saliva were MMP-8 and MMP-9. Salivary MMP levels and a ctivities in type 2 diabetic patients were in general similar to those in t he control group. However, the correlation coefficients using multiple regr ession analysis revealed that gingival bleeding, pocket depths and HbA(1c), were associated with increased MMP-8 levels which, in turn, were negativel y predicted by elevated plasma lipid peroxide levels in the diabetic group. Our data on salivary MMP-8 and -9 do not support the concept of generalize d neutrophil dysfunction in unbalanced diabetes. Moreover, plasma lipid per oxidation levels reflecting the increased oxidative burden, which is genera ted mainly by triggered neutrophils, do not indicate neutrophil dysfunction due to diabetes, but may rather be related to the increased tissue damage in an uncontrolled disease. However, advanced periodontitis in type 2 diabe tes seems to be related to elevated salivary MMP-8 levels which might be us eful in monitoring periodontal disease in diabetes.