Volume 12, Number 2, 409-420, DOI: 10.1007/s11373-005-3008-x

Carvedilol prevents cardiac hypertrophy and overexpression of hypoxia-inducible factor-1α and vascular endothelial growth factor in pressure-overloaded rat heart

Kou-Gi Shyu, Jer-Young Liou, Bao-Wei Wang, Wei-Jen Fang and Hang Chang

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Abstract

The use of beta-blockers has emerged as a beneficial treatment for cardiac hypertrophy. Hypoxia-inducible factor-1agr (HIF-1agr) is tightly regulated in the ventricular myocardium. However, the expression of HIF-1agr in cardiac hypertrophy due to pressure overload and after treatment with beta-blocker is little known. To evaluate the effect of carvedilol on both myocardial HIF-1agr expression and cardiac hypertrophy, infra-renal aortic banding was performed for 4 weeks in adult Sprague-Dawley rats to induce cardiac hypertrophy. Carvedilol at 50 mg/kg body weight per day after surgery was given. Heart weight and the ratio of heart weight and body weight increased significantly after aortic banding for 4 weeks in the absence of drug treatment. Mean arterial pressure increased from 80 ± 9 mmHg in the sham group to 94 ±5 mmHg (p < 0.001) in="" the="" banding="" group.="" echocardiography="" showed="" concentric="" hypertrophy="" after="" aortic="" banding.="" mean="" arterial="" pressure="" decreased="" after="" treatment="" with="" carvedilol.="" the="" increased="" wall="" thickness="" and="" heart="" weight="" was="" reversed="" to="" normal="" by="" carvedilol.="" western="" blot="" showed="" that="">agr, vascular endothelial growth factor (VEGF) and brain natriuretic peptide (BNP) proteins were up-regulated and nerve growth factor-beta (NGF-beta) down-regulated in the banding group. Treatment with valsartan, doxazosin, or N-acetylcysteine did not significantly affect HIF-1agr and VEGF proteins expression in the banding groups. Real-time polymerase chain reaction showed that mRNA of HIF-1agr, VEGF and BNP increased and mRNA of NGF-beta decreased in the banding group. Treatment with carvedilol reversed both protein and mRNA of HIF-1agr, VEGF, BNP, and NGF-beta to the baseline values. Increased immunohistochemical labeling of HIF-1agr, VEGF, and BNP in the ventricular myocardium was observed in the banding group and carvedilol again normalized the labeling. In conclusion, HIF-1agr, VEGF, and BNP mRNA and protein expression were up-regulated, while NGF-beta mRNA and protein was downregulated in the rat model of pressure-overloaded cardiac hypertrophy. Treatment with carvedilol is associated with a reversal of abnormal regulation of HIF-1agr,VEGF, BNP, and NGF-beta in the hypertrophic myocardium.

Keywords  aortic banding - cardiac hypertrophy - HIF-1agr - pressure overload - VEGF

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