Effect of long-term treatment with trandolapril on Hsp72 and Hsp73 induction of the failing heart following myocardial infarction.

1. The effect of long-term treatment of rats with chronic heart failure (CHF) following acute myocardial infarction with trandolapril, an angiotensin I-converting enzyme (ACE) inhibitor, on heat shock-induced Hsp72 and Hsp73 production was examined. 2. Acute myocardial infarction was induced by coronary artery ligation (CAL). The animals with CAL showed symptoms of CHF at the 8th week after the operation. The hearts isolated from animals with CAL at the 2nd and 8th week after surgery were subjected to hyperthermia at 42 degrees C for 15 min followed by 6-h perfusion (hyperthermia/6-h perfusion). 3. In the hearts isolated from the animals at the 2nd week, an approximate 20% decline in the rate pressure product (RPP) was seen after hyperthermia/6-h perfusion, which was similar to that in non-operated controls. In contrast, a significant reduction in the RPP after hyperthermia/6-h perfusion was seen in the hearts of rats with CHF. These hearts did not increase Hsp72 and Hsp73 production after hyperthermia. The decline in RPP was associated with failure in the production of myocardial Hsp72 and Hsp73. 4. When rats with CAL were treated with 3 mg kg(-1) day(-1) trandolapril from the 2nd to 8th week after the operation, the decline in RPP of the failing heart after hyperthermia was similar to that of the sham-operated rats. The induction of myocardial Hsp72 and Hsp73 production of the coronary artery-ligated rats after hyperthermia was reversed by treatment with trandolapril. 5. These findings suggest that the preserved ability to induce Hsp72 and Hsp73 production in the heart with CAL by trandolapril treatment may be attributed to the increased tolerance against heat stress-induced deterioration of myocardial contractile function.