Effects of angiotensin (1-7) upon right ventricular function in experimental rat pulmonary embolism

Right ventricular (RV) dysfunction contributes to poor clinical prognosis after pulmonary embolism (PE). The present studies evaluate the effects of angiotensin (1-7) (ANG (1-7)) upon RV function during experimental PE in rats. Circulating ANG II increased 8-fold 6 hr after PE (47±13 PE vs. 6±3 pg/mL, control, p<0.05). ACE2 protein was uniformly localized in the RV myocardium of control rats, but showed a patchy distribution with some cells devoid of stain after 6 or 18 hr of PE. RV function decreased 18 hr after PE compared with control treated animals (19±4 vs. 41±1 mmHg, respectively, p<0.05; 669±98 vs. 1354±77 mmHg/sec, respectively, p<0.05), while left ventricular function (LV) was not significantly changed. Animals treated with ANG (1-7) during PE showed improved RV +dP/dt and peak systolic pressure development to values not significantly different from control animals. Protection of RV function by ANG (1-7) was associated with improved arterial blood sO2, base excess and pH. Supplemental delivery of ANG (1-7) reduced the development of RV dysfunction, suggesting a novel approach to protecting RV function in the setting of acute experimental PE.