Suppression of Phosphoinositide 3-Kinase Prevents Cardiac Aging in Mice

Background—Heart failure is a typical age-associated disease. Although age-related changes of heart are likely to predispose aged people to heart failure, little is known about the molecular mechanism of cardiac aging. Methods and Results—We analyzed age-associated changes in murine heart and the manner in which suppression of the p110 isoform of phosphoinositide 3-kinase activity modified cardiac aging. Cardiac function declined in old mice associated with the expression of senescence markers. Accumulation of ubiquitinated protein and lipofuscin, as well as comprehensive gene expression profiling, indicated that dysregulation of protein quality control was a characteristic of cardiac aging. Inhibition of phosphoinositide 3-kinase preserved cardiac function and attenuated expression of the senescence markers associated with enhanced autophagy. Suppression of target of rapamycin, a downstream effector of phosphoinositide 3-kinase, also prevented lipofuscin accumulation in the heart. Conclusions—Suppression of phosphoinositide 3-kinase prevented many age-associated changes in the heart and preserved cardiac function of aged mice. (Circulation. 2009;120:1695-1703.) Key Words: aging heart failure insulin phosphoinositide 3-kinase rapamycin Heart failure is a typical age-associated disease and affectsprimarily people aged 60 years.1 The aging heart shows unique physiological and morphological characteristics.1–3 The changes that occur with aging in humans include an increase i