Figure 1.

Frequency analysis of endothelial progenitor cells (EPCs) from patients with end-stage kidney disease (ESKD). (a) Flow-cytometric protocol used to determine the percentage of circulating EPCs from whole blood. All cells were visualized on a forward versus side scatter plot and assessed for viability by gating on DAPI-negative cells. Viable vascular endothelial growth factor receptor-2 (VEGFR2^+/−) cells subgated with CD34⁺ cells. Of these, the CD45^dim population was subgated, and CD31⁺ expression on the resulting cells was confirmed on a CD31 histogram. This flow-cytometric protocol was used and established by Yoder et al.¹² Analysis was conducted using FlowJo software, and isotypes were used to for compensation. (b) Percentage of circulating EPCs for all patients in whole blood. The range of EPCs is spread from 3.8% down to 0.15% of whole blood in these patients (n = 13) with ESKD. Data are mean ± SD. APC, allophycocyanin fluorescent protein; FSC-A, forward scatter area; FSC-H, forward scatter height; PE, phycoerythrin fluorescent protein.