The role of endothelial progenitor and cardiac stem cells in the cardiovascular adaptations to age and exercise.

Age is a major risk factor for cardiovascular disease. Many hypotheses have been proposed to explain the ageing process. Ageing of tissue-specific as well as circulating stem and progenitor cell compartments can be viewed to be central to the decline of tissue and organ integrity and function in the elderly. Related to the cardiovascular system, circulating endothelial progenitor cells (EPCs) contribute to the endothelial integrity and function, and initiate adult neovascularization, while resident cardiac stem cells (CSCs) have the potential to differentiate into cardiomyocytes, endothelial or smooth muscle cells in the heart. Reduction in number and functional capacity of EPCs and CSCs might play a role in age-related vascular and cardiac dysfunction, leading to increased cardiovascular risk. In this review, we discuss the impact of ageing on EPCs and CSCs and their possible contribution to age-related cardiovascular adaptations. Regular aerobic physical activity has a strong cardioprotective effect, while physical inactivity is a central part of the aging process. Therefore, we also outline the immediate and long-term effects of physical activity on EPCs and CSCs.