Improvement of renal dysfunction in rats with chronic heart failure after myocardial infarction by treatment with the endothelin A receptor antagonist, LU 135252

Objective To investigate the role of an activated endothelin system in the renal dysfunction observed in chronic heart failure after myocardial infarc tion. Methods In rats with heart failure after myocardial infarction and in sham- operated animals (Sham), we investigated the effect on renal function of lo ng-term oral treatment with the selective endothelin A (ETA) receptor antag onist, LU 135252 (30 mg/kg per day; groups MI/LU and Sham/LU) or placebo (g roups MI/P, Sham/P). Only animals with extensive myocardial infarction (at least 46% of the left ventricle) were included in the study. Infarct size w as matched between groups MI/P and MI/LU. Endogenous creatinine clearance, fractional sodium excretion, and plasma and urinary concentrations of endot helin were determined 12 weeks after myocardial infarction. Results Endogenous 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 +/- SEM)). Treatment with LU 135252 completely prevented the decline in creatinine clearance in rats with chron ic myocardial infarction (MI/LU: 0.98 +/- 0.21; Sham/LU: 0.83 +/- 0.10). Fr actional sodium and protein excretion did not differ among the four groups. Group MI/P had a marked increase in plasma endothelin concentrations, whic h was not affected by treatment with LU 135252. Urinary endothelin excretio n was significantly lower in group MI/P than in group Sham/P. In the treatm ent groups, no difference could be observed between animals that had suffer ed myocardial infarction and the sham-operated group, although LU 135252 ma rkedly increased the urinary excretion of endothelin. Conclusion Our data demonstrate a restoration of impaired renal function in chronic ischaemic heart failure by treatment with the selective ETA recept or antagonist, LU 135252. These results offer a promising therapeutic optio n for the treatment of renal insufficiency in patients with chronic heart f ailure. J Hypertens 18:1507-1514 (C) 2000 Lippincott Williams & Wilkins.