Endothelial progenitor cells and endothelial vesicles - what is the significance for patients with chronic kidney disease?

Endothelial progenitor cells are cells derived from the bone marrow that circulate in the bloodstream and can exhibit phenotypic characteristics of endothelial cells. They are thought to be involved in postnatal vasculogenesis and to potentially help repair injured endothelium. Circulating endothelial cells are mature endothelial cells in the circulation, and endothelial vesicles or microparticles are thought to be derived from the membranes of endothelial cells as a result of injury or activation. Recent research has focused on using these markers of endothelial injury and repair to assess the state of endothelial health. These efforts have been hampered by lack of uniformity in methodology and terminology. Recent developments in flow cytometry techniques have allowed better characterization and definition of these cells. We review the common techniques used to identify and isolate these cells, clinical studies in patients with chronic kidney disease (CKD) where they serve as markers of endothelial health and predictors of outcome, and possible mechanisms of progenitor cell dysfunction in CKD.