Reversion of cardiovascular remodelling in renovascular hypertensive 2K-1C rats by renin-angiotensin system inhibitors.

Abstract

Evaluate whether the RAS dual blockade would induce additional beneficial effects on cardiovascular remodelling when compared to monotherapy in renal hypertensive two kidneys-one clip (2K-1C) rats. Hypertensive 2K-1C and normotensive (2K) rats were treated for 14days with submaximal doses of losartan (LOS), enalapril (ENA), losartan plus enalapril (LOS+ENA) or vehicle (water). Blood pressure and some parameters of cardiovascular remodelling were evaluated. Systolic blood pressure (SBP) was higher in 2K-1C (209±3mmHg, P<.05) than in 2K (113±1mmHg) rats. There was an additional effect in 2K-1C treated with LOS+ENA (153±9mmHg) on lowering SBP when compared to LOS (184±12mmHg) or ENA (177±9mmHg). None of the treatments had effect on SBP in 2K rats. In 2K-1C, cardiomyocyte hypertrophy was reduced by all treatments, although the cardiac hypertrophy indexes remained unchanged. 2K-1C aortas presented medial thickening that was partially reduced by the treatments. Intimal hyperplasia observed in 2K-1C (15.56±0.89µm vs 8.24±0.80µm) was reversed by ENA (9.52±0.45µm) or LOS+ENA (8.17±0.53µm). Collagen deposition was increased in 2K-1C hearts (1.77±0.16 vs 1.28±0.09) and aortas (8.1±0.6 vs 5.2±0.2). Treatment with LOS reduced (1.12±0.14%) and ENA (0.81±0.11%) or LOS+ENA (0.86±0.11%) additionally diminished collagen only in 2K-1C hearts. Submaximal doses of ACEi and/or ARB have inhibitory actions on cardiac remodelling and vascular hypertrophy not entirely dependent on their effects on blood pressure normalization in renovascular hypertensive rats. Combined therapy produced additional reduction in blood pressure than monotherapy despite a similar inhibition on cardiovascular remodelling.