Adipokines, myokines and cardiovascular disease.

It is recognized that obesity contributes to cardiovascular and metabolic disorders through alterations in the levels of adipocyte-derived cytokines (adipokines). Adiponectin is an adipokine that is downregulated in obese individuals. It has beneficial actions on the cardiovascular system by directly acting on the heart and blood vessels, and acute administration of adiponectin can minimize the tissue damage resulting from myocardial infarction. More recent research has been aimed at identifying novel adiponectin-like factors involved in metabolic and cardiovascular regulation. Activation of Akt, a protein kinase involved in cell signaling, has been implicated in the control of skeletal muscle hypertrophy. An experimental mouse model demonstrates that substantial increases in muscle fiber hypertrophy, weight and strength occur upon induction of Akt signaling in skeletal muscle. In a mouse model of obesity, the increase in muscle mass caused by myogenic Akt induction results in diminished fat deposition and improvements in whole body metabolism. Based on these findings a protocol to identify novel muscle-secreted proteins (myokines) that confer the phenotypic changes brought on by myogenic Akt induction has been devised. One of these newly discovered factors, referred to as follistatin-like 1, is able to promote revascularization in ischemic limbs and protect the heart from ischemic stress.