Effects of granulocyte-colony-stimulating factor on mobilization of bone-marrow-derived stem cells after myocardial infarction in humans.

Recent experimental studies have shown that granulocyte-colony-stimulating factor (G-CSF) enhanced cardiac function after infarction. The concept of direct cytokine or cell-mediated effects on postischemic myocardial function was tested in the setting of human myocardial infarction subjected to percutaneous coronary intervention. In the FIRSTLINE-AMI study 50 consecutive patients with first ST-elevation myocardial infarction were randomly assigned to receive either 10 microg/kg G-CSF for 6 days after percutaneous coronary intervention in addition to standard medication, or standard care alone. G-CSF administration led to mobilization of CD34(+) mononuclear stem cells (MNC(CD34+)), with a 20-fold increase to 64 +/- 37 MNC(CD34+)/microl at day 6 without significant associated changes in rheology, blood viscosity or inflammatory reaction, or any major adverse effects. At 4 months the G-CSF group showed improved left ventricular ejection fraction of 54 +/- 8% versus 48 +/- 4% at baseline (P <0.001), and no evidence of left ventricular end-diastolic remodeling, with a diameter of 55 +/- 5 mm and improved segmental wall thickening (P <0.001); conversely, in control patients left ventricular ejection fraction was 43 +/- 5% at 4 months (P <0.001), with increased left ventricular end-diastolic dimension of 58 +/- 4 mm (P <0.001), and no segmental wall thickening. In conclusion, the FIRSTLINE-AMI study showed that G-CSF administration and mobilization of MNC(CD34+) after reperfusion of infarcted myocardium may offer a pragmatic strategy for preservation of human myocardium and prevention of remodeling without evidence of aggravated atherosclerosis.

Prevention of left ventricular remodeling with granulocyte colony-stimulating factor after acute myocardial infarction: final 1-year results of the Front-Integrated Revascularization and Stem Cell Liberation in Evolving Acute Myocardial Infarction by Granulocyte Colony-Stimulating Factor (FIRSTLINE-AMI) Trial.

BACKGROUND: Experimental and clinical evidence has recently shown that pluripotent stem cells can be mobilized by granulocyte colony-stimulating factor (G-CSF) and may enhance myocardial regeneration early after primary percutaneous coronary intervention (PCI) management of acute myocardial infarction. Sustained or long-term effects of mobilized CD34-positive mononuclear stem cells, however, are unknown. METHODS AND RESULTS: Thirty consecutive patients with ST-elevation myocardial infarction undergoing primary PCI with stenting and abciximab were selected for the study 85+/-30 minutes after PCI; 15 patients were randomly assigned to receive subcutaneous G-CSF at 10 microg/kg body weight for 6 days in addition to standard care including aspirin, clopidogrel, an angiotensin-converting enzyme inhibitor, beta-blocking agents, and statins. In patients with comparable demographics and clinical and infarct-related characteristics, G-CSF stimulation led to sustained mobilization of CD34 positive mononuclear cells (MNC(CD34+)), with a 20-fold increase (from 3+/-2 at baseline to 66+/-54 MNC(CD34+)/microL on day 6; P<0.001); there was no evidence of leukocytoclastic effects, accelerated restenosis rate, or any late adverse events. Within 4 months, G-CSF-induced MNC(CD34+) mobilization led to enhanced resting wall thickening in the infarct zone of 1.16+/-0.29 mm (P<0.05 versus control), which was sustained at 1.20+/-0.28 after 12 months (P<0.001 versus control). Similarly, left ventricular ejection fraction improved from 48+/-4% at baseline to 54+/-8% at 4 months (P<0.005 versus control) and 56+/-9% at 12 months (P<0.003 versus control and paralleled by sustained improvement of wall-motion score index from 1.70+/-0.22 to 1.42+/-0.26 and 1.33+/-0.21 at 4 and 12 months, respectively), after G-CSF (P<0.05 versus baseline and P<0.03 versus controls). Accordingly, left ventricular end-diastolic diameter showed no remodeling and stable left ventricular dimensions after G-CSF stimulation, whereas left ventricular end-diastolic diameter in controls revealed enlargement from 55+/-4 mm at baseline to 58+/-4 mm (P<0.05 versus baseline) at 12 months after infarction and no improvement in diastolic function. CONCLUSIONS: Mobilization of MNC(CD34+) by G-CSF after primary PCI may offer a pragmatic strategy for improvement in ventricular function and prevention of left ventricular remodeling 1 year after acute myocardial infarction.