The angiotensin II AT1-receptor antagonist candesartan improves functional recovery and reduces the no-reflow area in reperfused ischemic rat hearts

It is not yet clear if cardiac angiotensin II is involved in the pathophysiology of myocardial ischemia/ reperfusion injury. The aim of this study was to investigate the effect of the angiotensin IT AT(1)-receptor antagonist candesartan on myocardial functional recovery in isolated rat hearts subjected to ischemia and reperfusion. Three groups of hearts perfused in the Langendorff mode with Krebs-Henseleit buffer under constant pressure received either vehicle (n = 7), candesartan, 1 nM (n = 6), or 100 nM (n = 7) at the start of 30 min of global ischemia. The recovery of the double product was significantly higher in the candesartan, 100 nM, group (75 +/- 9.2%) than in the vehicle group (40 +/- 5.1%; p < 0.05). At the end of 30 min of reperfusion, left ventricular end diastolic pressure was lower in rats given candesartan, 100 nM, than in rats given vehicle (10 +/- 3.3 vs. 38 +/- 4.8 mm Hg; p < 0.05). After ischemia and reperfusion, there was a large no-reflow area in the vehicle group (28 +/- 3.1% of the left ventricle), which was reduced by candesartan, 100 nM (12 +/- 1.3%; p < 0.05). In rats given candesartan, 1 nM, there was a trend toward a higher recovery of the double product (73 +/- 13.4%), a lower left ventricular end-diastolic pressure (29 +/- 6.6 mm Hg), and a smaller no-reflow area (19 +/- 3.5% of the left ventricle) compared with the rats receiving vehicle. These trends did, however, not reach statistical significance, Our results demonstrate that candesartan reduces myocardial ischemia/reperfusion injury, thus indicating that endogenous cardiac angiotensin IT is involved in the tissue injury after myocardial ischemia and reperfusion.