Coronary artery ligation in rats led to elevated left ventricular end-diastolic pressures (25 vs 5 mm Hg; P<0.001) and increased expression of Ang-(1-7) restricted to cardiac myocytes.
Does myocardial infarction induced by coronary artery ligation alter the expression of Ang-(1-7) in the myocardium of rats?
In a rat model of ischemic cardiomyopathy, heart failure subsequent to coronary artery ligation leads to increased expression of Ang-(1-7) restricted to cardiac myocytes.
Absolute Event Rate: 25% vs 5%
p-value: p=<0.001
BACKGROUND: Accumulating evidence suggests that angiotensin-(1-7) (Ang-1-7) may play an important role in counteracting the pressor, proliferative, and profibrotic actions of angiotensin II in the heart. Thus, we evaluated whether Ang-(1-7) is expressed in the myocardium of normal rats and those in which myocardial infarction was produced 4 weeks beforehand. METHODS AND RESULTS: The left coronary artery in 10-week-old Lewis rats was either ligated (n=5) or exposed but not occluded in age-matched controls (sham; n=5). Left ventricular end-diastolic pressures were significantly elevated 4 weeks after myocardial infarction (25+/-1 versus 5+/-1 mm Hg for sham; P<0.001), whereas left ventricular systolic pressures were significantly reduced (ligated 86+/-4 versus sham 110+/-5 mm Hg; P<0.01). Hemodynamic effects of coronary artery ligation were accompanied by significant cardiac hypertrophy (heart weight to body weight: ligated 4.3+/-0.1 versus sham 2.9+/-0.1 mg/g; P<0.001). In both ligated and sham rats, Ang-(1-7) immunoreactivity was limited to cardiac myocytes and absent in interstitial cells and coronary vessels. Ang-(1-7) immunoreactivity was significantly augmented in ventricular tissue surrounding the infarct area in the heart of rats with myocardial infarction. CONCLUSIONS: Development of heart failure subsequent to coronary artery ligation leads to increased expression of Ang-(1-7),which was restricted to myocytes.
Averill et al. (2003) studied Ischemic Cardiomyopathy (n=10). Coronary artery ligation vs. Sham operation was evaluated on Left ventricular end-diastolic pressure (p=<0.001). Coronary artery ligation in rats led to elevated left ventricular end-diastolic pressures (25 vs 5 mm Hg; P<0.001) and increased expression of Ang-(1-7) restricted to cardiac myocytes.