Abstract 9413: A Periodontal Pathogen Promotes Neointimal Formation after Arterial Injury Through Toll-Like Receptor-2 Signaling
Introduction-- Inflammatory response plays an important role in neointimal formation after an arterial injury. Previous studies demonstrated that periodontal bacteria were detected in atheromatous plaques, however, little is known about the effects of periodontal infection on vascular remodeling after mechanical injury. Toll-like receptors (TLRs) are key receptors of virulence factors of many periodontal bacteria.
Hypothesis-- We assessed the hypothesis that TLR-2 plays a pivotal role in a periodontopathic bacteria-induced neointimal formation after an arterial injury.
Methods-- Each mouse was implanted with a chamber subcutaneously. The chamber was used to inject bacterial infection into the mice. Two weeks after the chamber implantation, femoral arteries were injured and Porphyromonas gingivalis (P.g.), one of the major periodontopathic bacteria, or vehicle was injected once per week into the chamber. Fourteen days after the arterial injury, the murine femoral arteries were obtained for histopathological and immunohistochemical analyses.
Results-- In WT mice, the anti-P.g. IgG antibody level in plasma samples of the P.g.-injected group significantly increased compared to the vehicle injection group (6.5 ± 1.2-fold vs. vehicle injected group, p < 0.05). Histopathological analysis detected that the intima/media thickness ratio (I/M ratio) in the P.g.-injected group (4.54 ± 0.94, n = 11) significantly increased in comparison to the vehicle-injected group (2.31 ± 0.35, n = 11, p < 0.05). Immunohistochemical analysis detected that the P.g.-injected group showed more MCP-1 positive cells (29.0 ± 8.8 cells, n = 5) in the neointimal area compare to the vehicle-injected group (4.6 ± 1.9 cells, n = 5, p < 0.05). It is noteworthy that TLR-2 deficiency negated (1.74 ± 0.36, n = 10) P.g.-induced neointimal formation compared to the WT mice (4.54 ± 0.94, n = 11, p < 0.05). In TLR-2KO mice, I/M ratio in the P.g.-injected group (1.74 ± 0.36, n = 10) was comparable to the vehicle-injected group (1.54 ± 0.37, n = 6).
Conclusions-- These findings demonstrate that infection with P.g. could promote neointimal formation after an arterial injury through TLR-2 signaling.
- © 2011 by American Heart Association, Inc.