OBJECTIVETo examine the number and function of circulating endothelial progenitor cells (EPCs) in children with cyanotic congenital heart diseases (CHD) and study their correlation with serum levels of vascular endothelial growth factor (VEGF) and stromal cell derived factor-1 (SDF-1).

METHODSFifteen children with tetralogy of Fallot (cyanotic group) and 15 age-and sex-matched children with ventricular septal defect (control group) were enrolled. Serum levels of VEGF and SDF-1 were measured using ELISA. Mononuclear cells were isolated from peripheral blood by Ficoll density gradient centrifugation and cultured in vitro. EPCs were identified by immunofluorescence and were counted under a microscope. Modified Boyden chamber assay and the MTT assay were used to measure the migration and proliferation capacities of EPCs. EPCs adhesion ability assay was performed by replating cells on fibronectin-coated dishes, and then adherent cells were counted. The correlations of serum levels of VEGF and SDF-1 with the number and function of circulating EPCs were assessed by linear regression analysis.

RESULTSSerum levels of VEGF (201.42+/-44.74 ng/L vs 113.56+/-35.62 ng/L; P<0.05) and SDF-1 (3.45+/-1.07 ng/L vs 1.05+/-0.99 ng/L; P<0.05) in the cyanotic group were higher than those in the control group. There was a positive correlation between serum levels of VEGF and SDF-1(r=0.675, P<0.01). The number of EPCs (*200 field) in the cyanotic group significantly increased compared with that of the control group (72.2+/-9.73 vs 51.2+/-3.83; P<0.01). The functional activities of EPCs, including proliferation, migration and adhesion capacities, were augmented in the cyanotic group compared with those in the control group. The increased number and function of EPCs and the increased serum levels of VEGF and SDF-1 were consistent in the cyanotic group, with a correlation coefficient of 0.8395, 0.5491, 0.6376 and 0.7392 respectively.

CONCLUSIONSThe number and functional activity of EPCs as well as serum levels of VEGF and SDF-1 increased in children with cyanotic CHD. Serum levels of VEGF and SDF-1 were correlated to the number and functional activity of EPCs. Serum VEGF and SDF-1 together with circulating EPCs may play important roles in the pathology and physiology in these patients.