Stromal-derived factor-1α correlates with circulating endothelial progenitor cells and with acute lesion volume in stroke patients

BACKGROUND AND PURPOSE - Endothelial progenitor cells (EPC) are important participants of neovascularization and are mobilized through signaling with stromal-derived factor (SDF-1α), vascular endothelial growth factor (VEGF), granulocyte colony-stimulating factor, and stem cell factor. The association between EPC levels and these growth factors (GF) in acute stroke has not been previously established. We aimed to determine the association between EPC and these GF, and to elucidate a relationship between these GF and stroke severity in acute stroke patients. METHODS - Seventeen patients were selected from 175 patients with imaging-confirmed acute ischemic stroke. EPC were quantified using CD34, CD133, and VEGF-R2 markers. Plasma VEGF, SDF-1α, granulocyte colony-stimulating factor, and stem cell factor were determined by enzyme-linked immunosorbent assay on days 1 and 3, and brain MRI was performed at baseline and on days 1 and 5 after the stroke onset. RESULTS - Levels of SDF-1α strongly (r=0.6) correlated with the numbers of EPC subsets CD133VEFG-R2 (P<0.004), CD34VEGF-R2 (P<0.01), and CD34CD133VEGF-R2 (P<0.01) on day 1. Stem cell factor strongly (r=0.5) correlated with CD133VEGF-R2 (P<0.05). SDF-1α moderately inversely (r=-0.49) correlated with baseline diffusion-weighted imaging lesion volumes (P<0.04). Median levels of SDF-1α (1561 pg/mL) increased (P<0.04) on day 3 compared to day 1 (1379 pg/mL). Similarly, VEGF at day 3 (95 pg/mL) increased (P<0.03) compared to day 1 (64 pg/mL). CONCLUSIONS - These results indicate that SDF-1α and stem cell factor correlate with an increase in EPC early in ischemic stroke patients.