G-CSF after myocardial infarction accelerates angiogenesis and reduces fibrosis in swine

Recent studies have suggested that granulocyte colony-stimulating factor (G-CSF) may improve cardiac function after acute myocardial infarction (AMI) by accelerating angiogenesis or cardiomyogenesis, but negative results and side effect of G-CSF have also been reported. However, no previous studies have used large animal models of ischemia/reperfusion to investigate the effect and side effect of G-CSF after AMI.

The diagonal branch of the left anterior descending coronary artery of swine was balloon-occluded for 1 h and then reperfused. The animals of the G-CSF group were injected with G-CSF subcutaneously (5.0 microg/kg/day) for 6 days after MI and then sacrificed after 4 weeks. The control group received the same volume of saline.

There were no differences between the groups in the rate of thrombotic obstruction or progression of stenosis lesion in coronary angiography. The ejection fraction and end-diastolic volume in the G-CSF group were not significantly improved over the control values. The fibrotic area was significantly smaller in the G-CSF group than in the controls (P<0.05), and the numbers of vessels counted in anti-von Willebrand factor and anti-alpha-smooth muscle actin-stained sections were significantly larger (P<0.005 and P<0.05, respectively). The expression of collagen III mRNA was significantly lower in the G-CSF group than in the control in the infarct (P<0.0005) and border areas (P<0.005), and TGF-beta mRNA was significantly lower in the G-CSF group in the border area (P<0.05).

G-CSF could modify the healing process after AMI by accelerating angiogenesis in a swine ischemia/reperfusion model. At the dose administered, however, G-CSF did not seem to improve the global cardiac function.