Systemic Heme Oxygenase-1 Transgenic Overexpression Aggravates Pressure Overload-induced Cardiac Hypertrophy in Mice

Background/Aims: Heme oxygenase-1(HO-1) has been reported to protect against cardiac hypertrophy in cultured neonatal cardiomyocytes treated with HO-1 inducer, cardiac specific HO-1 transgenic mice, or animals treated with HO-1 inducer. The aim of the present study is to examine the effects of systemic HO-1 transgenic overexpression on pressure overload-induced cardiac hypertrophy in mice. Methods: Pressure-overload cardiac hypertrophy was induced by transverse aortic constriction (TAC) in WT (wild type) and systemic HO-1 transgenic overexpression (TG) mice. Results: We found that systemic HO-1 transgenic overexpression aggravated pressure overload-induced cardiac hypertrophy. Pressure-overload induced the more increases of heart weight/body weigh index, left ventricular weight/body weight index, beta-MHC protein expression, cardiac interstitial fibrosis in TG mice than in WT mice. Pressure-overload increased cardiac HO-1 protein expression in WT but not TG mice, but the cardiac HO-1 protein level was still higher in TAC-treated TG mice than in TAC-treated WT mice. The basal cardiac calcineurin protein level in TG mice was lower than that in WT mice. Pressure-overload increased calcineurin protein expression in both WT and TG mice; however, pressure-overload induced more calcineurin protein expression in TG mice than in WT mice. Conclusion: This study shows for the first time that systemic HO-1 transgenic overexpression aggravates pressure overload-induced cardiac hypertrophy. Copyright (C) 2011 S. Karger AG, Basel