Regulation of cardiac growth and coronary angiogenesis by the Akt/PKB signaling pathway.

Postnatal growth of the heart is primarily achieved through hypertrophy of individual myocytes. Cardiac growth observed in athletes represents adaptive or physiological hypertrophy, whereas cardiac growth observed in patients with hypertension or valvular heart diseases is called maladaptive or pathological hypertrophy. These two types of hypertrophy are morphologically, functionally, and molecularly distinct from each other. The serine/threonine protein kinase Akt is activated by various extracellular stimuli in a phosphatidylinositol-3 kinase-dependent manner and regulates multiple aspects of cellular functions including survival, growth and metabolism. In this review we will discuss the role of the Akt signaling pathway in the heart, focusing on the regulation of cardiac growth, contractile function, and coronary angiogenesis. How this signaling pathway contributes to the development of physiological/pathological hypertrophy and heart failure will also be discussed.