Increase in circulating CD34-positive cells in patients with angiographic evidence of moyamoya-like vessels.

Increasing evidence points to a role for circulating endothelial progenitor cells, including populations of CD34-positive (CD34(+)) cells, in maintenance of cerebral blood flow. In this study, we investigated the link between the level of circulating CD34(+) cells and neovascularization at ischemic brain. Compared with control subjects, a remarkable increase of circulating CD34(+) cells was observed in patients with angiographic moyamoya vessels, although no significant change was observed in patients with major cerebral artery occlusion (or severe stenosis) but without moyamoya vessels. Our results suggest that the increased level of CD34(+) cells associated with ischemic stress is correlated with neovascularization at human ischemic brain.