Eperythrozoon Suis Infection Enhances Atherosclerosis In Low-Density Lipoprotein Receptor-Deficient Mice

Background: Eperythrozoon (EP) infection in human shows high (35-70%) prevalence in northwest China. As this area also has the highest incidence of coronary disease in young people in China, we speculated that there is a possible association between EP infection and atherosclerotic development, which was tested in a murine model. Methods: EPs were isolated from three patients who were confirmed to have Eperythrozoon suis infection. Forty 10-week old wild type C57BL/6 and the same number of low-density lipoprotein receptor-deficient (LDLR-/-) C57BL/6 mice were inoculated respectively with human EP 10 times (once a day); and 20 C57BL/6 and the same number of (LDLR-/-) C57BL/6 mice were not injected with EPs as controls. The halves of EP inoculated mice were administrated with tetracycline. Atherosclerotic lesions and C5b-9 precipitation in aorta sections were visualized with Oil Red O staining and immunohistology 30 weeks after the last inoculation. Eperythrozoon suis antigen, antibody, complements, and cytokines in the blood and blood vessels were measured with ELISA. Results: Atheroma formation was accelerated after inoculation of EP in LDLR-/-mice. The atherosclerotic lesion size was significantly reduced after treatment with tetracycline (P<0.01), proinflammatory cytokine production, C3 turnover, C5b-9 precipitation, and atherosclerotic lesion size remained significantly different in the blood and within the aortas of infected mice compared with controls (P<0.01). Conclusions: EP suis infection activated complements, induced inflammatory cytokine expression, and aggravated atherosclerosis in murine models.