Endothelial progenitor cells: quo vadis?

Area of Science:

• Cardiovascular Biology
• Stem Cell Research
• Hematology

Background:

• Endothelial progenitor cells (EPCs) were initially defined by their endothelial-like properties in vitro, circulation to injury sites, and role in vascular repair.
• Over a decade later, most cells identified as EPCs are recognized as belonging to the hematopoietic lineage.
• A rare subset of circulating endothelial cells with proliferative potential exists, capable of forming new blood vessels.

Purpose of the Study:

• To review the lineage relationships of cells currently referred to as EPCs.
• To propose retiring the umbrella term EPC.
• To advocate for using existing terminology for distinct circulating cell subsets involved in vascular repair.

Main Methods:

• Literature review of studies defining and characterizing circulating cells with endothelial progenitor potential.
• Analysis of lineage markers and functional assays reported for various cell populations.
• Synthesis of current understanding of cell biology and contribution to neovascularization.

Main Results:

• The majority of cells historically labeled as EPCs originate from the hematopoietic system.
• True endothelial progenitor cells with sustained proliferative and vasculogenic capacity are rare in circulation.
• Existing nomenclature for hematopoietic and endothelial cell subsets adequately describes these distinct populations.

Conclusions:

• The broad term EPC is scientifically imprecise due to cellular heterogeneity.
• Retiring the term EPC will improve clarity and consistency in cardiovascular research.
• Future studies should utilize specific, established cell type names for better reproducibility and understanding of vascular repair mechanisms.