Myocardial homing of nonmobilized peripheral-blood CD34+ cells after intracoronary injection

Granulocyte-colony-stimulating factor administered for autologous hematopoietic stem cell isolation from blood may favor restenosis in patients implanted after acute myocardial infarction (AMI). We therefore tested the isolation of peripheral-blood CD34(+) cells without mobilization in six patients with AMI. After large-volume cytapheresis and positive CD34(+) cell selection, 3.6 to 27.6 million CD34(+) cells were obtained. We performed intracoronary implantation of these cells and recorded no restenosis or arrhythmia. We used positron emission tomography (PET) to assess myocardial-labeled CD34(+) cell homing, which accounted for 5.5% of injected cells I hour after implantation. In conclusion, large amounts of CD34(+) cells, in the range reported in previous studies, can be obtained from nonmobilized peripheral blood. PET with [F-18]-fluorodeoxyglucose cell labeling is an efficient imaging method for homing assessment.