Acute Myocardial Infarction is Reflected in Salivary Matrix Metalloproteinase-8 Activation Level

Background: The aim of this study is to compare salivary and serum biomarker levels and degrees of matrix metalloproteinase (MMP) activation between patients with acute myocardial infarction (AMI) and systemically healthy patients (non-AMI) with similar periodontal conditions. Methods: A total of 92 patients (47 AMI and 28 non-AMI patients with gingivitis or periodontitis; and 17 systemically and periodontally healthy patients as a control group) were recruited. Clinical periodontal measurements were recorded; stimulated whole saliva and serum samples were collected. AMI patients were clinically examined within 3 to 4 days after admission to the coronary care unit. Saliva samples were analyzed for levels of MMP-8, MMP-7, and tissue inhibitor of matrix metalloproteinase (TIMP)-1. Serums were tested for MMP-8, MMP-9, TIMP-1, and TIMP-2 levels by immunofluorometric assay and enzyme-linked immunosorbent assay. Molecular forms and degree of activation of salivary MMP-8, MMP-9, and MMP-13 were analyzed by computer-scanned immunoblots. Results: Total salivary MMP-8 assessed by immunofluorometric assay method and immunoblot densitometric units was higher in non-AMI than in AMI patients' saliva but a significantly higher percentage of AMI patients was activated polymorphonuclear leukocyte type (PMN) MMP-8 (P < 0.001) regardless of periodontal diagnosis. Serum MMP-8, MMP-9, and TIMP-1 levels were significantly higher in AMI (for all markers and all comparisons, P < 0.05). Characteristic for AMI was dominance of active PMN MMP-8 in saliva. Conclusions: Enhanced MMP-8 activation in the saliva of AMI patients is evidently, in part, of systemic origin. Consequently, AMI is reflected in serum but also in saliva. J Periodontol 2011;82:716-725.