Atherosclerosis is the most common cause for cardiovascular diseases and is based on endothelial dysfunction.

A growing body of evidence suggests the contribution of bone marrow–derived endothelial progenitor cells, monocytic cells, and mature endothelial cells to vessel formation and endothelial rejuvenation.

To this day, various subsets of these endothelial-regenerating cells have been identified according to cellular origin, phenotype, and properties in vivo and in vitro.

However, the definition and biology, especially of endothelial progenitor cells, is complex and under heavy debate.

In this review, we focus on current definitions of endothelial progenitor cells, highlight the clinical relevance of endothelial-regenerating cells, and provide new insights into cell-cell interactions involved in endothelial cell rejuvenation.

Key Words: endothelial-regenerating cells • colony-forming units • early EPCs • late EPCs • circulating EPCs • endothelial-like cells

Hypertension. 2010;55:593

Martin Steinmetz; Georg Nickenig; Nikos Werner

From the Medizinische Klinik und Poliklinik II, Universitätsklinikum Bonn, Bonn, Germany.

Correspondence to Nikos Werner, Sigmund Freud Str 25, 53127 Bonn, Germany. E-mail nikos.werner@ukb.uni-bonn.de