Elevated Matrix Metalloproteinase Levels in Bronchi Infected with Periodontopathogenic Bacteria

Objectives To determine whether bronchial colonisations/infections with periodontopathogenic bacteria are associated with elevated inflammatory markers such as MMPs, interleukins and Tumor necrosis factor alpha in the bronchial fluid. Methods Periodontal status was assessed in consecutive outpatients planned for elective bronchoscopies, and PCR for periodontopathogenic bacteria was performed from a protected specimen brush sample taken from the bronchial mucosa. Additionally, MMPs, interleukins and Tumor necrosis factor alpha were measured in the bronchial fluid. Results Out of the four species assessed, one species was found in 13 of 91 (14%) patients, and two in 12 (13%), three in 13 (14%) and all four in 1 (1%) patient, respectively. In multiple linear regression models the presence of Treponema denticola showed a consistent pattern of positive effects in bronchial fluid (Bonferroni adjusted p-values) on the levels of MMP9 (p adj.: 0.028) and MMP12 (p adj.: 0.029). Active smoking was independently associated with increased levels of aMMP8 (p adj.: 0.005) and MMP9 (p adj.: 0.009). Levels of IL-1 beta, IL-8 and Tumor necrosis factor alpha measured in the bronchial fluid were not affected by the presence of periodontopathogenic bacteria. Conclusions Bronchial colonisation/infection with Treponema denticola and smoking are independently associated with elevated MMPs (MMP9/MMP12 and MMP8/MMP9, respectively) in the bronchial fluid.