Impact of serum source and inflammatory cytokines on the isolation of endothelial colony-forming cells from peripheral blood

Endothelial colony-forming cells (ECFCs) isolated from peripheral blood are a highly promising cell source for a wide range of applications, including tissue engineering, in vivo vasculogenesis and anti-cancer therapeutics. Because of the potential for clinical translation, it is increasingly important to isolate and study ECFCs from patient cohorts that may benefit from such technologies. The primary objective of this investigation was to determine whether ECFCs could be obtained from patients with chronic kidney disease and diabetes (CKD-DM), using techniques that can be readily applied in the clinical setting. We also investigated the impact of autologous vs commercially available (i.e. allogeneic) human serum on ECFCs isolation. Surprisingly, the efficacy of ECFCs isolation from the CKD-DM group was comparable to a healthy control group when autologous serum was used. In contrast, substitution of allogeneic serum reduced ECFCs isolation in CKD-DM and control groups. In characterization studies, ECFCs were positive for several endothelial cell markers. ECFCs from the CKD-DM group were sensitive to inflammatory activation but their cellular proliferation was compromised. The concentrations of IL-4 and IL-8 were significantly increased in allogeneic serum, which induced a pro-inflammatory environment, including the release of IL-4, IL-6, IL-8 and MCP-1 into the conditioned media of cell cultures. Taken together, these data support further investigation into the use of autologous serum and cells for ECFC-based therapeutics and underscore the importance of the cytokine content in serum used for ECFCs isolation.