Impairment of cardiac energy metabolism in vivo causes hemodynamic abnormality and increases cardiac expression of preproendothelin-1 mRNA.

We investigated whether impairment of myocardial energy metabolism attenuates cardiac function and increases cardiac endothelin-1 (ET-1) gene expression in rats. Three weeks after commencing administration of cobalt chloride (CoCl2), an inhibitor of mitochondrial function, the peak positive first derivative of left ventricular (LV) pressure, an indicator of myocardial contractility, was significantly decreased in the CoCl2-treated rats. LV end-diastolic pressure and right ventricular systolic pressure were increased in the CoCl2-treated rats. Echocardiography showed that fractional shortening was significantly decreased in the CoCl2-treated rats. Myocardial expressions of acyl-CoA synthase mRNA, an enzyme involved in fatty acid utilization, was markedly decreased in the CoCl2-treated rats. Under such conditions, myocardial expression of preproendothelin-1 mRNA and atrial natriuretic peptide (ANP) mRNA, molecular markers of heart failure, was markedly increased in the CoCl2 rats. In conclusion, the data suggest that impairment of myocardial energy metabolism causes hemodynamic abnormality and increases molecular markers of heart failure (ET-1, ANP mRNA). These data suggest that myocardial energy metabolism is one of the factors involved in the upregulation of ET-1 gene expression in the failing heart.