Granulocyte colony-stimulating factor does not enhance recruitment of bone marrow-derived cells in rats with acute myocardial infarction.

Despite the potential benefit of granulocyte colony-stimulating factor (G-CSF) therapy in patients with acute myocardial infarction (MI), the efficacy of G-CSF in regenerating the heart after MI remains controversial. The authors hypothesize that the limited efficacy of G-CSF is related to its inhibitory effect on recruitment of bone marrow-derived cells (BMCs) to the infarcted tissue. MI was induced in rats with intrabone marrow-bone marrow transplantation from syngenic rats expressing green fluorescence protein to track BMCs. G-CSF was administered for five days after the onset of MI. G-CSF increased the number of CD45(+) cells in the peripheral circulation but did not increase their recruitment to the heart. G-CSF had no effect on myocardial stromal-derived factor-1 alpha and chemokine (C-X-C motif) receptor 4 (CXCR4) expression in mononuclear cells in the peripheral blood and CXCR4(+) cells in the heart. G-CSF had no effect on angiogenesis, myocardial fibrosis or left ventricular function four weeks after MI. These results suggest that G-CSF mobilizes BMCs to the peripheral circulation but does not increase recruitment to the infarcted myocardium despite preservation of the stromal-derived factor-1 alpha/CXCR4 axis.