Cardioprotective effects of granulocyte colony-stimulating factor in swine with chronic myocardial ischemia

OBJECTIVES The aim of this study was to investigate the effect of granulocyte colony-stimulating factor (G-CSF) on chronic myocardial ischemia in swine. BACKGROUND We recently have reported that G-CSF prevents cardiac remodeling and dysfunction after acute myocardial infarction in mice and swine. It remains unclear whether G-CSF has beneficial effects on chronic myocardial ischemia. METHODS An ameroid constrictor was placed on left circumflex coronary artery of swine. The presence of myocardial ischemia was verified at four weeks after the operation, and the animals were randomly assigned into the following two groups: 1) administration of vehicle (control group, n = 10), and 2) administration of G-CSF (10 mu g/kg/day) for seven days (G-CSF group, n = 10). RESULTS Echocardiographic examination revealed that the G-CSF treatment prevented left ventricular dilation and dysfunction at eight weeks after the operation. Stress echocardiograpliv revealed that G-CSF ameliorated the regional contractility of chronic myocardial ischemia. Morphological analysis revealed that the extent of myocardial fibrosis of the ischemic region was less in the G-CSF group than in control group. There were more vessels and less apoptotic ceus at the ischemic region of the heart of the G-CSF group than control group. Moreover, Akt1 was more strongly activated in the heart of the G-CSF group than control group. CONCLUSIONS These findings suggest that G-CSF improves cardiac function of chronic myocardial ischemia through decreases in fibrosis and apoptotic death and an increase in vascular density in the ischemic region.