Abstract
We aimed to study the endothelial dysfunction among children and adolescents with transfusion-dependent -thalassemia using von Willebrand factor antigen (VWF:Ag) and flow cytometric analysis of circulating CD144(+) endothelial microparticles (EMPs) and endothelial progenitor cells (CD34(+)VEGFR2(+)) and assess their relation to iron overload, erythropoietin and chelation therapy as well as echocardiographic parameters and carotid intima-media thickness. The VWF:Ag, EMPs, and CD34(+)VEGFR2(+) cells were significantly higher among patients with -thalassemia than controls (P < .001). The type of chelation and patients' compliance did not influence the results. No significant correlations were found between the studied vascular markers. Patients with evident heart disease had higher VWF: Ag, EMPs, and CD34(+)VEGFR2(+) cells than those without. Carotid intima-media thickness was increased among patients but not correlated with vascular markers. We suggest that procoagulant EMPs and VWF: Ag are involved in cardiovascular complications in patients with young -thalassemia. CD34(+)VEGFR2(+) cells were further increased in response to tissue injury contributing to reendothelialization and neovascularization.