Circulating endothelial cells Biomarker of vascular disease
Andrew D. Blann , Alexander Woywodt , Francesco Bertolini , Todd M. Bull , Jill P. Buyon , Robert M. Clancy , Marion Haubitz(2) , Robert P. Hebbel(6) , Gregory Y. H. Lip (1) , Patrizia Mancuso(3) , Jose Sampol (7) , Anna Solovey (6) , Fran ç oise Dignat
(1) Haemostasis Thrombosis and Vascular Biology Unit, University Department of Medicine, City Hospital, Birmingham, United Kingdom (2) Department of Medicine, Division of Nephrology, Hannover Medical School, Hanover, Germany (3) Division of Haem
Recent research has recognised new populations of non-hematopoïetic
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.