Salivary matrix metalloproteinase-8 in patients with and without coronary heart disease may indicate an increased susceptibility to periodontal disease

Background and Objective: Tissue destruction caused by periodontitis may increase the number of cytokines implicated in the pathogenesis of cardiovascular diseases. We measured the concentration of the leukocyte-derived proteolytic enzyme, salivary neutrophil collagenase-2 [matrix metalloproteinase-8 (MMP-8)], as a marker of periodontal disease and assessed its relationship to coronary heart disease (CHD). Our aim was to study whether salivary MMP-8 levels were different among patients with and without CHD. The hypothesis was that patients with heart disease might present higher salivary MMP-8 levels than cardiologically healthy controls. Material and Methods: Saliva samples were taken from 256 patients with CHD and from 250 matched controls with known oral and general health status. The MMP-8 levels in saliva were analyzed by immunofluorometric assay, salivary albumin was assessed by enzyme-linked immunosorbent assay (ELISA) and total protein was determined using the colorimetric method. We further investigated the molecular forms and isoform distribution of salivary MMP-8 by western immunoblotting. The MMP-8 results were adjusted for the number of teeth and salivary protein concentrations. Results: The adjusted logarithmic MMP-8 values were 0.145 +/- 0.245 mu g/l in patients with CHD and 0.088 +/- 0.115 mu g/l in controls (p < 0.01). The respective MMP-8 : total protein and MMP-8 : albumin ratios were also significantly higher in CHD patients than in non-CHD subjects. Conclusion: Elevated salivary MMP-8 levels seemed to associate with CHD, suggesting more tissue breakdown as a result of periodontitis among the patients with heart disease.