Value and level of circulating endothelial progenitor cells, angiogenesis factors and mononuclear cell apoptosis in patients with chronic kidney disease.

BACKGROUND: Chronic renal failure on dialysis can reduce the number of circulating endothelial progenitor cells (EPCs), but this biomarker has not been fully investigated in patients with chronic kidney disease (CKD). A link between CKD and increased mononuclear cell apoptosis (MCA) in circulation has been reported but the effect of vascular endothelial growth factor (VEGF) and stromal cell-derived factor (SDF)-1α, two angiogenesis factors, on circulating EPC levels in CKD has not been clarified. This study examined the relationships between the numbers of circulating EPCs and the severity of CKD, degree of MCA and serum levels of VEGF and SDF-1α in CKD patients.
METHODS: The numbers of circulating EPCs (CD31/CD34+, CD62E/CD34+, KDR/CD34+, CXCR4/CD34+) were measured in 166 patients with varying degrees of CKD under regular treatment at an outpatient department and in 30 volunteer control subjects.
RESULTS: CKD patients had significantly lower numbers of EPCs (p < 0.007), higher MCA in circulation and higher serum levels of VEGF and SDF-1 compared with the control subjects (all p < 0.001). Compared with patients with early CKD (stages I-III), patients with late CKD [stage IV-V or end-stage renal disease (ESRD)] had significantly lower numbers of EPCs (CXCR4/CD34+), higher MCA, and elevated serum levels of VEGF and SDF-1α (all p < 0.01). Serum VEGF level but not MCA or SDF-1α was strongly correlated with increased numbers of circulating EPCs. Multivariate analysis showed that ESRD along with lower serum albumin was independently predictive of lower numbers of circulating EPCs (p < 0.04).
CONCLUSION: Circulating EPCs were markedly reduced in CKD patients. ESRD was strongly and independently predictive of decreased numbers of circulating EPCs.