Project Summary The proposed study will investigate the role of endothelial progenitor cells in neurovascular dysfunction and cognitive decline among older adults with low levels of traditional vascular risk and normal baseline cognitive function. Specifically, we will study whether changes in endothelial progenitor cell proliferation and senescence are predictive of cognitive decline, vascular brain lesions and structural and functional brain connectivity. We will also study secretory factors from endothelial progenitor cell cultures to better understand how progenitor cell function relates to neurovascular dysfunction, brain injury and cognitive decline.