ObjectiveTo investigate the role of an activated endothelin system in the renal dysfunction observed in chronic heart failure after myocardial infarction.MethodsIn rats with heart failure after myocardial infarction and in sham-operated animals (Sham), we investigated the effect on renal function of long-term oral treatment with the selective endothelin A (ETA) receptor antagonist, LU 135252 (30 mg/kg per day; groups MI/LU and Sham/LU) or placebo (groups MI/P, Sham/P). Only animals with extensive myocardial infarction (at least 46% of the left ventricle) were included in the study. Infarct size was matched between groups MI/P and MI/LU. Endogenous creatinine clearance, fractional sodium excretion, and plasma and urinary concentrations of endothelin were determined 12 weeks after myocardial infarction.ResultsEndogenous creatinine clearance was significantly lower in group MI/P than in group Sham/P (MI/P:0.64 ± 0.05, Sham/P: 0.81 ± 0.04 ml/min per 100 g body weight;P= 0.01 (means 6 SEM)). Treatment with LU 135252 completely prevented the decline in creatinine clearance in rats with chronic myocardial infarction (MI/LU: 0.98 ± 0.21; Sham/LU: 0.83 ± 0.10). Fractional sodium and protein excretion did not differ among the four groups. Group MI/P had a marked increase in plasma endothelin concentrations, which was not affected by treatment with LU 135252. Urinary endothelin excretion was significantly lower in group MI/P than in group Sham/P. In the treatment groups, no difference could be observed between animals that had suffered myocardial infarction and the sham-operated group, although LU 135252 markedly increased the urinary excretion of endothelin.ConclusionOur data demonstrate a restoration of impaired renal function in chronic ischaemic heart failure by treatment with the selective ETA receptor antagonist, LU 135252. These results offer a promising therapeutic option for the treatment of renal insufficiency in patients with chronic heart failure.