Colony Forming Unites-Endothelial Progenitor Cells (CFU-EPCs): A Surrogate Marker for Diabetic Retinopathy and High Cardiovascular Mortality Rate

Purpose: Diabetic retinopathy is a risk factor for increased cardiovascular death. Our purpose was to find a significant difference in levels of endothelial progenitor cells (EPCs) in the peripheral blood of patients at different stages of diabetic retinopathy. Design: A prospective study. Colony forming units of endothelial progenitor cells (CFU-EPCs) in peripheral blood were counted. 40 subjects were enrolled (10 healthy (41 ± 8 y), 10 type 2 diabetes mellitus (T2DM) (64 ± 12 y) without retinopathy, 10 T2DM patients (62 ± 26 y) with non-proliferative retinopathy (NPDR), 10 T2DM patients (66 ± 9 y) with proliferative retinopathy (PDR)). The study was approevd by the ethics committee of the hospital and every subject signed a soncent form before enrollment. Methods: Growing CFU-EPCs was by the Hill's EPCs protocol. Blood was drawn early in the morning and was processed within 1 hour. Mononuclear cells were separated and cultured on fibronectin-coated plates with EndoCult medium (Stem Cell technologies, Vancouver BC Canada) for 5 days. CFU-EPCs were counted on day 5 (an average of 8 wells). Results: Healthy subjects had 36 ± 8 CFU-EPCs, patients without retinopathy had 13 ± 12 CFU-EPCs (p<0.01), patients with NPDR 22 ± 26 CFU-EPCs (p=NS), and 2 ± 2 CFU-EPCs in patients with PDR (p<0.01). A significant difference was found between patients with PDR and with NPDR (p<0.05). Conclusions: CFU-EPCs are inhibited in T2DM patients with DPR. Levels of CFU-EPCs may be used as a surrogate biologic marker for severity of diabetic retinopathy and for cumulative vascular-risk.