Expression of CXCR4, VLA-1, LFA-3 and transducer of ERB in G-CSF-mobilised progenitor cells in acute myocardial infarction

G-CSF induced mobilisation of progenitor cells is a multistep processes involving chemokines, growth factors, matrix-degrading enzymes, and cell adhesive interactions mediated by specific receptors on haematopoietic cells. This study's aim was to investigate progenitor cells mobilised during myocardial infarction after treatment with granulocytestimulating factor (G-CSF). In the randomised, double-blind, placebocontrolled REVIVAL-2 study, 114 patients with acute myocardial infarction were included. Five days after successful percutaneous coronary intervention patients received either 10 μg/kg G-CSF (n=56) or placebo (n=58) subcutaneously for five days. Venous blood samples were analysed on day(s) 1, 3, 5 and 7 after therapy, and progenitor cell mobilisation and surface expression of VLA-4, LFA-1 and CXCR-4 was measured on circulating progenitor cells using flow cytometry. G-CSF induced a significant increase in circulating progenitor cells (72 ± 20 cells/μl vs. 4.5 ± 0.8 cells/μl, p<0.05). Surface expression of LFA-1, VLA-4 and CXCR4 on progenitor cells was decreased by 44%, 49% and 60% after G-CSF as compared to placebo (p<0.05). In accordance, mRNA expression of CXCR4 was reduced. Moreover, anti-proliferative transducer of ERB (TOB) mRNA was decreased, suggesting an increased proliferative potential of the mobilised progenitor cells. Decreased expression of adhesion and chemokine receptors on G-CSF mobilised progenitor cells in acute myocardial infarction may alter the homing capacity of circulating cells to the myocardium.