Treatment with the selective ETA receptor antagonist Lu135252 prevented the deterioration of LV end-diastolic pressure and abolished alterations in -dP/dt(max) and SR Ca2+ reuptake (P<0.05).
Does selective ETA receptor antagonism prevent left ventricular dysfunction in a rat model of renin-dependent hypertension?
ETA receptor antagonism prevents the transition to left ventricular dysfunction in renin-dependent hypertension by normalizing sarcoplasmic reticulum calcium uptake, independent of blood pressure reduction.
p-value: p=<0.05
BACKGROUND: We evaluated the role of the cardiac endothelin (ET) system in compensated hypertensive left ventricular (LV) hypertrophy (LVH) and after the transition toward LV dysfunction. METHODS AND RESULTS: Hypertensive transgenic rats overexpressing the Ren2 gene (Ren2 rats) were investigated between the ages of 10 and 30 weeks (Ren2-10 and Ren2-30 groups, respectively) and compared with age-matched normotensive Sprague-Dawley (SD) rats (SD-10 and SD-30 groups, respectively). Systolic blood pressure and LV weight were elevated in both Ren2 groups compared with their age-matched SD control groups (P:<0.0001). In Ren2-30 rats, LV end-diastolic pressure increased and -dP/dt(max) decreased compared with the values in SD-30 and Ren2-10 rats (P:<0.05). This was paralleled by an activation of LV mRNA expression of preproET-1 and ET-converting enzyme-1 and ET subtype A (ETA) receptor binding in Ren2-30 compared with Ren2-10 rats (P:<0.001). Cardiac fibrosis was increased and sarcoplasmic reticulum (SR) Ca(2+) reuptake was reduced in Ren2-30 compared with SD-30 and Ren2-10 rats (P:<0.05). Treatment of Ren2 rats with the selective ETA receptor antagonist Lu135252 between 10 and 30 weeks of age did not lower systolic blood pressure, heart weight, or cardiac fibrosis but completely prevented the deterioration of LV end-diastolic pressure and abolished alterations in -dP/dt(max) and SR Ca(2+) reuptake compared with no treatment in Ren2-30 and SD-30 rats (P:<0.05). CONCLUSIONS: Activation of the cardiac ET system accounts at least in part for the LV dysfunction that gradually develops in LVH. The protective effect of ETA antagonism can be attributed to the improvement of diastolic LV function that is due to normalization of impaired SR Ca(2+) uptake.
Rothermund et al. (Tue,) conducted a other in Hypertensive left ventricular hypertrophy and dysfunction. Selective ETA receptor antagonist Lu135252 vs. No treatment was evaluated on LV end-diastolic pressure, -dP/dt(max), and SR Ca(2+) reuptake (p=<0.05). Treatment with the selective ETA receptor antagonist Lu135252 prevented the deterioration of LV end-diastolic pressure and abolished alterations in -dP/dt(max) and SR Ca2+ reuptake (P<0.05).
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