Increased expression of cardiac angiotensin II type 1 (AT(1)) receptors decreases myocardial microvessel density after experimental myocardial infarction

Objective: To study the effects of increased levels of myocardial angiotensin II type I (AT,) receptor on microvascular growth following myocardial infarction (MI). Methods: MI was created in transgenic rats (TGR) with a cardioselective overexpression of the AT(1) receptor. We used Sprague-Dawley (SD) rats as controls. Some of the rats were treated with the selective AT(1) receptor blocker losartan (Los). Rats were sacrificed after 3 weeks. Results: MI caused left ventricular (LV) hypertrophy and LV dysfunction in both SD and TGR, which was prevented by AT, receptor blockade. Furthermore, MI decreased microvessel density in the non-infarcted myocardium (SD MI: 1653+/-37 /mm(2), p