ABSTRACT
BACKGROUND AND OBJECTIVE: Men are at higher risk for periodontal and cardiovascular diseases compared with women, although they have lower serum levels of risk markers, including lipids and acute phase proteins. In this study, we investigated whether infection with a major periodontal pathogen, Porphyromonas gingivalis, affected the inflammatory and atherosclerotic response of male and female mice differently. MATERIAL AND METHODS: Forty-eight heterozygous apolipoprotein E-deficient mice (24 males and 24 females), maintained on normal diet, were infected twice by intrasubcutaneous chamber injections of P. gingivalis or vehicle at weeks 11 and 14 of age. Serum samples were collected before the first infection and bi-weekly thereafter, to quantify levels of high-density lipoprotein (HDL) cholesterol and the murine acute phase protein, serum amyloid A (SAA). Mice were killed at week 17 to evaluate aortic atheroma lesion score. RESULTS: Males had significantly higher baseline HDL cholesterol levels (p < 0.01, factorial ANOVA). Following P. gingivalis infection, HDL cholesterol levels decreased over time in infected males only [p < 0.05, generalized estimating equation (GEE)], whereas SAA levels increased and remained elevated over time in both male and female infected mice (p < 0.01, GEE). Lesion scores were significantly higher in infected mice (3-fold, p < 0.01, factorial ANOVA), and lesion scores of all mice were positively correlated with SAA levels at the time of killing (Spearman correlation coefficient = 0.40, p < 0.01). CONCLUSION: In these young mice, P. gingivalis infection induced sex-specific changes in serum lipids but no gender differences in acute phase proteins and atheroma lesion score.
