A novel pleiotropic effect of statins: prevention of cardiac hypertrophy by cholesterol-independent mechanisms.

Cardiac hypertrophy is an initial physiological adaptive response by the heart to pressure overload. However, if pressure overload persists, frequently, the heart decompensates and develops 'pathophysiological' hypertrophy. This leads to increased mortality and morbidity and is an independent risk factor for heart failure. Because cardiac myocytes convert this pressure overload into intracellular biochemical signals, blocking this critical signaling pathway may be an important therapeutic target to prevent cardiac hypertrophy. Small GTP-binding proteins, in particular Rac1, have been suggested to play a key role in the development of cardiac hypertrophy. Recently, 3-hydroxyl-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, also called statins, have been shown to inhibit cardiac hypertrophy independent of their cholesterol lowering property. Statins block the isoprenylation and activation of members of the Rho family, such as RhoA and Rac1. Rac1 also regulates NADPH oxidase, which is a major source of reactive oxygen species (ROS) in cardiovascular cells. Growing evidence suggests that ROS may be involved in the process of cardiac hypertrophy and recent research has shown that statins attenuate oxidative stress through inhibition of Rac1. Overall, these pleiotropic effects of statins will give new insights into the process of cardiac hypertrophy.