Atherosclerosis-preventive activity of anti-phosphorylcholine antibody may be interfered by infection with Porphyromonas gingivalis : The Nagasaki Islands study.

Objectives: Oxidized form of low-density lipoprotein (ox-LDL) is implicated in the pathogenesis of atherosclerosis. Recently, antibodies reactive to oxidization specific epitopes of LDL are suggested to prevent from progression of atherosclerosis. Phosphorylcholine (PC), which is a major component of the cell membrane lipid, is considered to be the epitope on ox-LDL. On the other hand, it is suggested that periodontal diseases are likely related to atherosclerosis. We thus investigated the influence of periodontal infection on potent atherosclerosis-preventive activity of anti-PC antibodies in saliva and plasma.
Methods: Forty-three individuals (mean age, 69.4 years) who attended the mass health examination held in both 2009 and 2012 at Goto City, Nagasaki Prefecture, Japan were subjected in this study. Saliva and plasma samples were obtained and cardio-ankle vascular index (CAVI) was measured as the indicator of atherosclerosis. The state of periodontal infection was evaluated by the level of IgG antibody for Porphyromonas gingivalis (Pg). Anti-Pg IgG antibody level in plasma and anti-PC antibody (IgM, IgG and IgA) levels in saliva and plasma were determined by ELISA. Subjects were divided into two groups according to the anti-Pg IgG antibody titers, low titer (<10 units) group and high titer (≥10 units) group. A multiple logistic regression analysis was performed to evaluate the association between the levels of anti-PC antibodies and atherosclerosis. In addition, three years after the first examination, follow-up assessment for CAVI was performed and atherosclerosis-preventive activity of anti-PC antibody was examined.
Results: In the low anti-Pg group (n=27), the higher level of plasma anti-PC IgM was significantly associated with the lower CAVI (p=0.041) and the higher level of salivary anti-PC IgM showed a trend toward lower CAVI (p=0.079). In the high anti-Pg group (n=16), significant relationship was not observed between atherosclerosis and anti-PC antibodies. In the follow-up assessment, the higher level of plasma anti-PC IgM showed a trend toward lower risk for progression of atherosclerosis in the low anti-Pg group (p=0.068), whereas no significant relationship was observed in the high anti-Pg group.
Conclusions: Infection with Pg may interfere the atherosclerosis-preventive activity of anti-PC antibodies.