Porphyromonas gingivalis Bacteremia Induces Coronary and Aortic Atherosclerosis in Normocholesterolemic and Hypercholesterolemic Pigs

Abstract

Objectives— The aim of this study was to determine whether recurrent intravenous injections with Porphyromonas gingivalis ( P gingivalis ), mimicking periodontitis-associated bacteremia, promotes coronary artery and aortic atherosclerosis in pigs. Methods and Results— Pigs (n=36) fed low- or high-fat chow were divided into P gingivalis –sensitized and P gingivalis –challenged groups or P gingivalis –sensitized controls and saline-treated controls. Pigs were sensitized with 10 9 killed P gingivalis subcutaneously. Four weeks later all sensitized pigs in the group to be challenged started intravenous injections thrice weekly for 5 months with 10 6 to 10 7 colony forming units of P gingivalis while controls received saline. Anti– P gingivalis antibody, serum cholesterol, and complete blood counts were assayed monthly. Pigs were euthanized 2 weeks after the last injection, and coronary arteries and aortas were analyzed by histomorphometry and immunohistochemistry. Anti– P gingivalis antibody was increased by P gingivalis exposure. P gingivalis –challenged pigs developed a significantly greater amount of coronary and aortic atherosclerosis than controls in the normocholesterolemic group and nearly significant in the hypercholesterolemic group. P gingivalis was detected by polymerase chain reaction in arteries from most (94%, 16 of 17) P gingivalis –challenged pigs but not controls. Conclusions— Recurrent P gingivalis bacteremia induces aortic and coronary lesions consistent with atherosclerosis in normocholesterolemic pigs and increases aortic and coronary atherosclerosis in hypercholesterolemic pigs.