Increased circulating progenitor cells in Alzheimer's disease patients with moderate to severe dementia: evidence for vascular repair and tissue regeneration?

Cerebrovascular dysfunction is a common finding in patients with Alzheimer's disease (AD) and may contribute to cognitive decline. Abundant evidence suggests that vascular and neuronal repair mechanisms are mediated by circulating progenitor cells in vivo. Whether CD34+ and, specifically, CD34+/CD133+ progenitor cells are involved in the pathophysiology of AD is poorly understood so far.