Granulocyte colony-stimulating factor (G-CSF) and erythropoietin are two 
cytokines that have been demonstrated to improve cardiac function and perfusion 
in myocardial infarction. G-CSF was initially evaluated as a stem cell mobilizer 
and erythropoietin as a cytoprotective agent. However, both cytokines have 
direct cytoprotective effects and stem cell-mobilizing ability. Direct 
cytoprotective effects of both cytokines are commonly mediated by the Jak-STAT 
pathway. In preclinical study, G-CSF and erythropoietin improved cardiac 
function and perfusion by angiomyogenesis and protection of cardiomyocytes in 
myocardial infarction. However, results from recent clinical trials did not 
support beneficial effects of cytokine therapy with G-CSF or erythropoietin 
alone in patients with myocardial infarction. Further studies are required to 
elucidate the mechanism of action and to improve therapeutic efficacy by 
employing novel strategies, such as combined cytokines.