Insulin-like growth factor-1 in myocardial tissue: interaction with tumor necrosis factor

Insulin-like growth factor (IGF)-1 is a well characterized growth factor that plays a role in the regulation of myocardial structure and function. Using an ex vivo murine model, Davani and coworkers, in this issue of Critical Care, demonstrate that IGF-1 confers cardiac protection against ischemia via mitochondria-dependent mechanisms. Those investigators used the ratio of mitochondrial to nuclear DNA to demonstrate that IGF-1, which prevents reduction in this ratio during reperfusion, provides cytoprotection. This commentary also reviews mechanisms of IGF-1 function and provides a graphic representation of IGF-1 signaling mechanisms in potential crosstalk relations with mediators of inflammation in the heart (specifically tumor necrosis factor-α).