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Relation of circulating progenitor cells to vascular function and oxidative stress with long term training and short term detraining in older men

September 1st, 2009 by admin Leave a reply »

Exercise may contribute to the maintenance of vascular function via enhanced liberation and action of bone marrow-derived progenitor cells. Activity-related changes in oxidative stress may also influence the number and function of these cells. We sought to determine whether adaptations in reactive hyperemic forearm blood flow (FBF) response associated with long-term endurance exercise and short-term detraining were related to resting putative progenitor cell number and function and to determine whether oxidative stress affected these factors. Participants included men with greater than 30 years of moderate- to high-intensity exercise (HI) history and healthy low active age- and BMI- matched control subjects (LO). Vascular reactive hyperemic FBF response, resting CD34⁺ and CD34⁺/VEGFR2⁺ cell number, colony forming unit-endothelial cell (CFU-EC) count, and CFU-EC senescence were evaluated. Oxidative stress measures included oxidized LDL (OxLDL) and total antioxidant capacity (TAC). These measures were assessed following 10-days of detraining in HI men. HI men had greater peak reactive hyperemic FBF response compared with LO men despite no difference in resting CD34⁺ cell number, CD34⁺/VEGFR2⁺ cell number, CFU-EC colonies, or CFU-EC senescence. With detraining in HI, CD34⁺ cells declined 44% and the percent change in CD34⁺/VEGFR2⁺ cells was positively correlated with the change in FBF response to reactive hyperemia. The percent change in CD34⁺/VEGFR2⁺ cells and the percent change in EPC senescence with detraining were related to the percent change in total antioxidant capacity. These data reveal that changes in reactive hyperemic FBF are closely related to activity-dependent dynamic changes in CD34⁺/VEGFR2⁺ cell number, which may be influenced by alterations in oxidative stress.