Circulating endothelial cells. Biomarker of vascular disease.
Recent research has recognised new populations of non-hematopoietic cells in the blood. One of these, circulating endothelial cells (CECs), often defined by the expression of membrane glycoprotein CD146, are rarely found in the blood in health, but raised numbers are present in a wide variety of human conditions, including inflammatory, immune, infectious, neoplastic and cardiovascular disease, and seem likely to be evidence of profound vascular insult. An additional population are endothelial progenitor cells, defined by the co-expression of endothelial and immaturity cell surface molecules and also by the ability to form colonies in vitro. Although increased numbers of CECs correlate with other markers of vascular disease, questions remain regarding the precise definition, cell biology and origin of CECs. For example, they may be damaged, necrotic or apopototic, or alive, and could possess procoagulant and/or proinflammatory properties. However, since these cells seem to be representative of in situ endothelium, their phenotype may provide useful information. Indeed, whatever their phenotype, there is growing evidence that CECs may well be a novel biomarker, the measurement of which will have utility in various clinical settings related to vascular injury. Despite this promise, progress is impeded by the diversity of methodologies used to detect these cells. Accordingly, results are sometimes inconclusive and even conflicting. Nevertheless, increased CECs predict adverse cardiovascular events in acute coronary syndromes, suggesting they may move from being simply a research index to having a role in the clinic. The objective of the present communication is to condense existing data on CECs, briefly compare them with progenitor cells, and summarise possible mechanism(s) by which they may contribute to vascular pathology.
Blann
Andrew D
AD
Haemostasis Thrombosis and Vascular Biology Unit, University Department of Medicine, City Hospital, Birmingham, B18 7QH, UK. a.blann@bham.ac.uk
Woywodt
Alexander
A
Bertolini
Francesco
F
Bull
Todd M
TM
Buyon
Jill P
JP
Clancy
Robert M
RM
Haubitz
Marion
M
Hebbel
Robert P
RP
Lip
Gregory Y H
GY
Mancuso
Patrizia
P
Sampol
Jose
J
Solovey
Anna
A
Dignat-George
Françoise
F
D000818:Animals; D015415:Biomarkers / Q000097:blood; D002452:Cell Count; D042783:Endothelial Cells / Q000473:pathology; D004730:Endothelium, Vascular / Q000473:pathology*; D006412:Hematopoietic Stem Cells / Q000166:cytology; D006801:Humans; D014652:Vascular Diseases / Q000175:diagnosis*
D015415:Biomarkers