BACKGROUND: Experimental studies and early-phase clinical trials suggest that transplantation of blood-derived or bone marrow-derived stem cells may improve cardiac regeneration after acute myocardial infaction (AMI). Granulocyte-colony stimulating factor (G-CSF) induces mobilization of bonemarrow stemcells. OBJECTIVES: To assesss the value of stemcell mobilization by G-CSF therapy in patients with AMI. METHODS: We enrolled 114 patients with the diagnosis of AMI. Enrollment was performed 5 days after successfull reperfusion by percutaneous coronary intervention. Patients were randomly assigned to receive subcutaneously either daily dose of 10µg/kg G-CSF (56 patients) or placebo (58 patients) for 5 days. We measured infarct size at baseline and 4-6 months followup by Technetium 99m-sestamibi scintigraphy. During the five day treatment surface markers like CD 34, CXCR4, VLA-4 and LFA-1 were quantified by flowcytometry. The primary endpoint of the study was reduction of leftventricular infarct size. Secondary endpoits included improvement in left ventricular ejection fraction (LVEF), measured by magnetic resonance imaging and angiographic restenosis. RESULTS: Treatment with G-CSF produced a significant mobilization of CD34 positive stemcells. In the G-CSF group the expression of CXCR4 and the adhesion molecules LFA-1 and VLA-4 were reduced in flow cytometry. Between baseline and follow-up left ventricular infarct size in scintigraphy was reduced by 6.2±9.1% in the G-CSF group and 4.9±8.9% in the placebo group (p=0.45) and LVEF was improved by 2.8±3.7% in the G-CSF group and 2.8±3.5% in te placebo group (p=0.98). The incidence of angiographic restenosis was 35.2% in the G-CSF group and 30.9% in the placebo group (p=0.64). CONCLUSION: Stemcell mobilization by G-CSF therapy in patients with acute myocardial infarction and successfull mechanical reperfusion had no influence on infarct size, LVEF and coronary restenosis.
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