The study aimed to investigate whether the extent of activities of daily living (ADL) of patients after myocardial infarction affect numbers of circulating CD34(+)/KDR(+) and CD45(+)/CD34(+) cells, which are supposed to protect structural and functional endothelial integrity. In a cross-sectional study, 34 male coronary artery disease patients with a history of myocardial infarction were assessed for times spent per week for specific physical ADL, including basic activities (instrumental ADL), leisure time activities, and sport activities, using a validated questionnaire. Individual specific activity times were multiplied with respective specific metabolic equivalent scores to obtain levels of specific activities. Numbers of circulating CD34(+)/KDR(+) and CD45(+)/CD34(+) cells were analyzed by flow cytometry. Furthermore, the colony-forming capacity of CD34(+) cells and the level of granulocyte colony-stimulating factor (G-CSF) in serum were measured. Analysis revealed that the extent of total activities and basic activities, as well as total activity time, were positively correlated with numbers of circulating CD34(+)/KDR(+) cells (r = 0.60, 0.56, and 0.55, P < 0.05). Higher levels of total activity were also associated with increased colony-forming capacity of CD34(+) cells (r = 0.54, P < 0.05) and with higher systemic levels of G-CSF (r = 0.44, P < 0.05). These findings indicate that even ADL-related activities of coronary artery disease patients after myocardial infarction exert stimulating effects on CD34(+)/KDR(+) cell mobilization, potentially mediated by increased G-CSF levels. This, in turn, potentially contributes to the beneficial effects of exercise on the diseased cardiovascular system.
Keywords: coronary artery disease; endothelial function; endothelial progenitor cells; exercise; physical activity.