Endothelin-A receptor antagonist combined with hydralazine improves survival and renal function in hypertensive rats.

To investigate the role of endothelin (ET) in severe hypertension, endothelial dysfunction hypercholesterolemic stroke-prone spontaneously hypertensive rats (SHRSP on a 5% cholesterol diet) were additionally fed with 1% NaCl and 0.023% nitro-L-arginine. Under these conditions, all untreated rats died within 30 days (median 17 days). A significant prolongation of survival (median 33 days) was achieved by combination treatment with hydralazine and the ETA receptor antagonist LU 135252. Monotherapy was less effective (LU 135252 18 days; hydralazine 28 days). Likewise, only treatment with the combination completely prevented the increase in systolic arterial pressure (SAP) seen in the control group during the first 10 days and delayed development of hypertension during the subsequent observation period. The superior efficacy of the combination was also reflected by improved kidney function. After 20 days of treatment, proteinuria had only increased to 1,272 +/- 135 mg/kg/day, a reduction of 45% compared to the untreated control group (2,300 +/- 346 mg/kg/day; p < 0.05). In this animal model of aggravated hypertension and endothelial dysfunction, the combination of LU 135252 with hydralazine was superior compared to either monotherapy. Therefore, the combination of an ETA receptor antagonist with vasodilators may be a potent therapy to improve blood pressure, renal function, and survival in severe hypertension with concomitant metabolic disease.