Objectives: To compare the efficacy and feasibility between intracoronary and hypodermic injection of granulocyte colony-stimulating factor (G-CSF) on improving cardiac function in a Swine model of chronic myocardial ischemia.
Methods: Eighteen Swine underwent placement of ameroid constrictor on left circumflex coronary artery. The presence of myocardial ischemia was verified at four weeks after the operation, and the animals were then randomly assigned into three groups (n = 6 each): (1) administration of vehicle (control), (2) hypodermic injection of G-CSF (5 microgxkg(-1)x;d(-1)) for five days (IH), and (3) intracoronary injection of a bonus G-CSF (60 microg/kg) (IC). Coronary angiogram, cardiac MRI, and (18)F-FDG-SPECT/(99m)Tc-SPECT (DISA-SPECT) measurements were performed at pre-administration and at 4 weeks post administration. Global heart function such as left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVSDV) and left ventricular ejection fraction (LVEF), myocardial perfusion, myocardial viability and myocardial infarct area were evaluated. Myocardial vWF, Bcl-2 and Bax expressions were detected by Western blot and RT-PCR.
Results: MRI data showed that left ventricular dilation and dysfunction were similarly prevented in IH and IC G-CSF treated animals at eight weeks after the operation. SPECT revealed that both IH and IC G-CSF equally improved the regional contractility of chronic myocardial ischemia and increased myocardial viability. Myocardial infarct size was also reduced after both G-CSF treatments as detected by MRI. Intracoronary injection of G-CSF did not lead to angiogenesis in other organs. G-CSF treatments were also associated with a significant reduction in myocardial apoptosis and significant increase in angiogenesis.
Conclusions: Both intracoronary and hypodermic injection of G-CSF were safe and feasible and could equally improve cardiac function and increase angiogenesis in this Swine model of chronic myocardial ischemia.