Defining human endothelial progenitor cells

Abstract

Summary. There is no specific marker to identify an endothelial progenitor cell (EPC) and this deficiency is restricting the ability of an entire field of research in defining these cells. We will review current methods to define EPC in the human system and suggest approaches to define better the cell populations involved in neoangiogenesis. PubMed was used to identify articles via the search term ‘endothelial progenitor cell’ and those articles focused on defining the term were evaluated. The only human cells expressing the characteristics of an EPC, as originally proposed, are endothelial colony forming cells. A variety of hematopoietic cells including stem and progenitors, participate in initiating and modulating neoangiogenesis. Future studies must focus on defining the specific hematopoietic subsets that are involved in activating, recruiting, and remodeling the vascular networks formed by the endothelial colony forming cells.

Endothelial Nitric Oxide Synthase as A Marker for Human Endothelial Progenitor Cells

“…However, conflicting results have been reported in the field, and the identification and characterization of EPCs in vascular biology is still a subject of much discussion. Yoder (2009) has concluded that EPCs could be defined by three general approaches in the human system: method of culture and the morphological criteria; monoclonal antibodies and fluorescence activated cell sorting (FACS) analysis to enumerate specific cell populations; colony forming assay in vitro, though all of these approaches have defects. In most reports, combination of different surface markers was embraced for the identification of EPCs.…”

Neovascularization Potential of Blood Outgrowth Endothelial Cells From Patients With Stable Ischemic Heart Failure Is Preserved

“…BOECs belong to the family of endothelial progenitor cells (EPCs), which harbors a heterogeneous selection of different cell types, participating in and modulating neovascularization. Distinct EPC subtypes are defined using different culture techniques and/or combinations of cell surface markers 1, 2, 3. BOECs, also referred to as circulating endothelial colony‐forming cells (ECFCs) or late outgrowth EPCs, are the only cell type featuring the characteristics of a “true” EPC, given that these cells are self‐renewing, clonogenic, and able to form capillary‐like structures and integrate into functional blood vessels in vitro and in vivo, respectively 4…”

Vasculogenesis in Diabetes-Associated Diseases: Unraveling the Diabetic Paradox

“…This defective endothelial repair could be normalized by transfusion of progenitor cells from insulin-sensitive animals, but not from insulin-resistant animals (Kahn et al, 2011). However, it is thought that EPCs biological modifications are mostly affected by IR in an indirect fashion, through the increase in ROS and also by the activation of pro-inflammatory cytokines (Cubbon et al, 2007;2009;Houstis et al, 2006). In fact, IR states are closely linked to the increased production of ROS, which is a characteristic feature of IR and thought to play a causal role in its development (Houstis et al, 2006).…”

“…The characterization of these different subpopulations of EPCs is due to the different methodology used for cell isolation. To date, there are three main techniques that have been used to select, identify and characterize EPCs (Hirschi et al, 2008;Yoder, 2009). The cell types isolated using the different protocols are not phenotypically similar and as such, their www.intechopen.com potential to influence neovascularization and/or vascular repair may vary.…”