Angiotensin II Type 1a Receptor Signals are Involved in the Progression of Heart Failure in MLP-Deficient Mice

Rie Yamamoto, Hiroshi Akazawa, Kaoru Ito, Haruhiro Toko, Masanori Sano, Noritaka Yasuda, Yingjie Qin, Yoko Kudo, Takeshi Sugaya, Kenneth R. Chien, Issei Komuro
2007 Circulation Journal  
Animals G1 pups generated from an MLP +/-heterozygote× AT1a -/homozygote cross were mated to created the MLP +/-/ AT1a +/double heterozygotes (G2). G4 offspring were gen-Background Angiotensin II (AT) is implicated in the development of cardiac remodeling, which leads to heart failure, and pharmacological inhibition of the AT type 1 (AT1) receptor has improved mortality and morbidity in patients of heart failure. The aim of this study was to elucidate the role of the AT1 receptor in disease
more » ... ptor in disease progression in muscle LIM protein (MLP)-deficient mice, which are susceptible to heart failure because of defective function of mechanosensors in cardiomyocytes. Method and Results Hearts from MLP knockout (MLPKO) mice and MLP-AT1a receptor double knockout (DKO) mice were analyzed. MLPKO hearts showed marked chamber dilatation with cardiac fibrosis and reactivation of the fetal gene program. All of these changes were significantly milder in the DKO hearts. Impaired left ventricular (LV) contractility and filling were alleviated in DKO hearts. However, the impaired relaxation and downregulated expression of sarcoplasmic reticulum calcium-ATPase 2 were unchanged in DKO hearts. Conclusions The AT1a receptor is involved in progression of LV remodeling and deterioration of cardiac function in the hearts of MLPKO mice. These results suggest that blockade of the receptor is effective in preventing progression of heart failure in dilated cardiomyopathy. (Circ J 2007; 71: 1958 -1964
doi:10.1253/circj.71.1958 pmid:18037754 fatcat:7se55xn5yfenxmnc4s6olaks5i