Abstract
Although angiotensin converting enzyme (ACE) inhibitors are considered useful for the treatment of human heart failure, some experimental failing-heart models have shown little beneficial effect of ACE inhibitors in animals with poor oral health, particularly periodontitis. In this study, we examined the effects of the ACE inhibitor captopril (Cap; 0.1 mg/mL in drinking water) on cardiac dysfunction in mice treated with Porphyromonas gingivalis lipopolysaccharide (PG-LPS) at a dose (0.8 mg/kg/day) equivalent to the circulating level in patients with periodontal disease. Mice were divided into four groups: 1) Control, 2) PG-LPS, 3) Cap, and 4) PG-LPS + Cap. After1 week, we evaluated cardiac function by echocardiography. The left ventricular ejection fraction was significantly decreased in PG-LPS-treated mice compared to the control (from 66 ± 1.8 to 59 ± 2.5%), while Cap ameliorated the dysfunction (63 ± 1.1%). The area of cardiac fibrosis was significantly increased (approximately 2.9-fold) and the number of apoptotic myocytes was significantly increased (approximately 5.6-fold) in the heart of PG-LPS-treated group versus the control, and these changes were suppressed by Cap. The impairment of cardiac function in PG-LPS-treated mice was associated with protein kinase C δ phosphorylation (Tyr-311), leading to upregulation of NADPH oxidase 4 and xanthine oxidase, and calmodulin kinase II phosphorylation (Thr-286) with increased phospholamban phosphorylation (Thr-17). These changes were also suppressed by Cap. Our results suggest that the renin-angiotensin system might play an important role in the development of cardiac diseases induced by PG-LPS.