Abstract 30: 4-PBA Prevents TAC-induced Myocardial Hypertrophy and Interstitial Fibrosis by Attenuating ER Stress in Mice
Background: Recently, 4-phenylbutyric acid (4-PBA) has been recognized as a potent ER stress inhibitor and a histone deacetylase inhibitor, but its therapeutic effect in cardiovascular diseases is still not fully understood. Our previous study indicated that attenuation of ER stress by administration of low dosage of 4-PBA (20 mg/kg/d) prevented post-infarction-induced cardiac rupture and remodeling through modulating both cardiac apoptosis and fibrosis in the mouse model of myocardial infarction. However, little is known whether the administration of 4-PBA is effective for hypertrophic heart disease. The aim of this study is therefore to test the therapeutic effect of 4-PBA on pressure-overload induced myocardial hypertrophy.
Methods and Results: Transverse aortic constriction (TAC) was used to produce pressure-overload in C57BL/6 male mice for 4 weeks. After surgery, 4-PBA (20mg/kg/d) or 0.9% NaCL was intraperitoneally injected daily. At the end of 4 weeks, the survivals were underwent high-resolution echocardiographic imaging observation. The results showed that the left ventricular posterior wall thickness at end systole (LVPWs) and left ventricular posterior wall thickness at end diastole (LVPWd) were increased in TAC group. Administration of 4-PBA ameliorated this hypertrophic effect. Autopsy also confirmed the anti-hypertrophic effect of 4-PBA. Masson-staining found that there was no difference in perivascular fibrosis between TAC and TAC+4-PBA groups. However, myocardial interstitial fibrosis and collagen deposition were significant decreased by 4-PBA. We finally detected the ER stress and histone acetylation using western blotting. Our results showed that 4-PBA, at the dosage of 20 mg/kg/day, decreased the expression of CHOP and had no effect on histone 3 acetylation.
Conclusion: These findings indicate that attenuating ER stress by 4-PBA maybe a promising therapeutic strategy to prevent pressure-overload induced myocardial hypertrophy and interstitial fibrosis.
Author Disclosures: T. Luo: None. B. Chen: None. X. Wang: None.
- © 2015 by American Heart Association, Inc.