Recent studies suggest that reductions in circulating endothelial progenitor cells (EPCs) may contribute to the development of
atherosclerosis. However, whether reduced circulating EPCs contribute to
cerebrovascular disease remains undefined. We tested the hypothesis that reduced circulating EPCs was associated with an increased burden of
carotid atherosclerosis. The level of circulating CD34+/KDR+ EPCs and the extent of
carotid atherosclerosis were determined in 30 patients with a history of atherothrombotic
ischaemic stroke and 30 age- and sex-matched controls (mean age: 63+/-2 years; 63% men).
Stroke patients, compared with controls, had significantly higher carotid mean maximum intima-media thickness (
mmIMT) (1.08+/-0.05 versus 0.90+/-0.02 mm, P=0.002), prevalence of carotid plaque (60.0 versus 23.3%, P=0.004) and a lower number of circulating CD34+/KDR+ EPCs (235.7+/-45.5 versus 400.4+/-56.8 cells/mul, P=0.027). The circulating CD34+/KDR+
EPC count correlated negatively with carotid
mmIMT (r=-0.50, P<0.001), and was an independent risk factor for increased carotid
mmIMT>1 mm (odds ratio (OR): 7.71; 95% confidence interval (CI): 1.62-36.74, P=0.010) and the presence of carotid plaque (OR: 7.04; 95% CI: 1.95-25.43, P=0.003). Furthermore,
stroke patients with low (<25th percentile of controls) as compared to those with normal CD34+/KDR+
EPC count had a significantly greater carotid
mmIMT (1.21+/-0.07 versus 0.93+/-0.05 mm, P=0.005) and a significantly higher prevalence of carotid plaque (87.5% versus 28.6%; P=0.001). Our observations suggested that reduced circulating
EPC may contribute to the progression of
carotid atherosclerosis. Circulating
EPC count may provide a novel marker for the burden of
carotid atherosclerosis.