Abstract
BackgroundDysregulation of the vascular endothelium and endothelial cells precede the initiation and progression of hypertension. Endothelial progenitor cells (EPCs) have been isolated from circulating mononuclear cells in human peripheral blood and shown to be incorporated into foci of angiogenesis and neovascularization. Herein, we explored the characteristics and functions of a sub-type of highly proliferative and angiogenic EPC, known as endothelial colony-forming cells (ECFCs).Methods and ResultsWe isolated ECFCs from peripheral blood of 10 individuals. The CD31+ KDR+ VE-cadherin+ ECFCs express endothelial and progenitor cell surface antigens (Fig.1A). The ECFCs displayed a stable endothelial cobblestone phenotype with clonal proliferative potential, capacity to form in-vitro tubule structures on Matrigel, and response to shear stress (Fig.1A). Hierarchical clustering of ECFC proteome profiles revealed two clusters with cluster 1 having better proliferation and in vitro-tube formation capacities as compared to cluster 2 (Fig.1C). Cluster 2 showed elevated systolic blood pressure in comparison to cluster 1 (cluster 1121.9±3.7mmHg; cluster 2142.1±6.1mmHg, P=0.02). The proteomic analysis further identified 263 differentially-expressed proteins between clusters (≤-2 or ≥2 fold change with ≥2 unique peptides). Comparative pathway analysis showed significant differences in extracellular matrix organisation between clusters.ConclusionThe findings demonstrate the feasibility of harvesting and using ECFCs as a platform of in-vitro angiogenesis microvascular assessment in patients and that ECFC functionality associates with variation in blood pressure. The differences in proteome expression may identify pathways that can be therapeutically targeted to improve ECFC functionality.