Different subpopulations of endothelial progenitor cells and circulating apoptotic progenitor cells in patients with vascular disease and diabetes

Abstract

Aims: Endothelial progenitor cells (EPCs) represent a repair mechanism involving reendothelialization and neoangiogenesis. Patients with both diabetes and known vascular disease have low numbers of circulating EPCs. To assess the role of diabetes in vascular disease we investigated the number and viability of circulating EPCs and related this to endothelial function.

Methods: Different EPC subpopulations were enumerated by flow cytometry using triple staining (CD34, CD133, KDR). Viability was assessed by 7AAD and Annexin-V-staining. Endothelial function was evaluated by Endo-PAT2000 in 19 patients with known vascular disease without diabetes and 20 patients with vascular disease and diabetes mellitus.

Results: CD34+, CD133+, CD34+/CD133+, CD34+/KDR+, CD34+/CD133+/KDR+ cell counts did not differ between patients with and without diabetes. CD34-/CD133+/KDR+ cells were lower, whereas staining for apoptosis in progenitor cells was higher in patients with diabetes. Progenitor cell counts did not correlate to peripheral arterial function test.

Discussion: Patients having diabetes and vascular disease have lower CD34-/CD133+/KDR+ EPC counts, a recently discovered subpopulation of EPCs, and larger proportion of apoptotic EPCs. Higher apoptotic rates of progenitor cells in diabetes could represent an important mechanism explaining lower functional capability of these cells. These observations may be of importance for the complications associated with diabetes mellitus.