G-CSF therapy for acute myocardial infarction.

Granulocyte-colony-stimulating factor (G-CSF) has recently been shown to have various effects besides promoting the proliferation and differentiation of myeloid progenitor cells, including the mobilization of bone marrow stem cells and the regeneration infarcted hearts in mice. Recent animal studies have also revealed that G-CSF activates multiple signaling pathways, such as Akt and also the Janus family kinase-2 and signal transducer and activation of transcription-3 (Jak2-STAT3) pathway, in cardiac myocytes. It prevents left ventricular remodeling after myocardial infarction by decreasing cardiomyocyte death and by increasing the number of blood vessels, suggesting the importance of direct actions of G-CSF on the myocardium rather than through mobilization and differentiation of stem cells. Several clinical trials have been performed to study the efficacy of G-CSF therapy in patients with acute myocardial infarction but the results remain controversial because the protocols followed varied between the trials.