Reduced endothelial progenitor cells in children with hemodialysis but not predialysis chronic kidney disease

In adults with chronic kidney disease (CKD), reduced levels of vasculoprotective endothelial progenitor cells (EPCs) may contribute to their increased risk of cardiovascular disease. Children with CKD also show signs of cardiovascular disease. However, to our knowledge, there have been no studies on circulating EPC levels in pediatric patients with CKD. We investigated CD34+KDR+ EPC numbers by using flow cytometry in 15 children with predialysis CKD, 13 children on hemodialysis, and 18 age-matched healthy controls. Children on hemodialysis showed 47% reduced EPC levels compared with controls, whereas no significant difference was found for patients with predialysis CKD. Lower EPC levels were found in patients with higher levels of inflammatory marker high-sensitivity C-reactive protein. Our data show, for the first time, that children on hemodialysis have reduced CD34+KDR+ EPC levels, which potentially contributes to their increased cardiovascular risk. In children with predialysis CKD, a decline in renal function was not associated with reduced EPC levels, which may reflect a capacity for preservation of the endogenous repair system during relatively moderate disturbances of the systemic environment.