Submitted on November 13, 2007
Accepted on January 24, 2008
A maximal exercise bout increases the number of circulating CD34+/KDR+ endothelial progenitor cells in healthy subjects. Relation with lipid profile
Emeline MF Van Craenenbroeck1*, Christiaan J. Vrints2, Steven E. Haine3, Katrien Vermeulen4, Inge Goovaerts3, Viggo FI Van Tendeloo5, Vicky Y. Hoymans1, and Viviane MA Conraads1
1 Department of Cardiology, University Hospital Antwerp, Belgium; Center for Cellular Therapy and Regenerative Medicine (CCRG), University Hospital Antwerp, United States
2 Department of Cardiology, University Hospital Antwerp, Antwerp, Belgium; Center for Cellular Therapy and Regenerative Medicine (CCRG), University Hospital Antwerp, Antwerp, Belgium
3 Department of Cardiology, University Hospital Antwerp, Belgium
4 Vaccine & Infectious Disease Institute (VIDI), Laboratory for Experimental Hematology, University of Antwerp, Belgium
5 Center for Cellular Therapy and Regenerative Medicine (CCRG), University Hospital Antwerp, United States; Vaccine & Infectious Disease Institute (VIDI), Laboratory for Experimental Hematology, University of Antwerp, Belgium
* To whom correspondence should be addressed. E-mail: Emeline.Vancraenenbroeck{at}ua.ac.be.
Mobilisation of bone marrow-derived endothelial progenitor cells (EPC) might explain exercise-induced improvement of endothelial function. We assessed whether a maximal exercise bout could alter the number of circulating EPC in healthy subjects and whether this effect is related to their cardiovascular risk profile. Additionally, we investigated possible mediators of this effect, namely nitric oxide (NO) bioavailability and vascular endothelial growth factor (VEGF) release. Healthy subjects (group 1, n=11; group 2, n= 14) performed a symptom-limited cardiopulmonary exercise test (CPET) on a bicycle ergometer. Numbers of CD34+/KDR+ cells were determined by flow cytometric analysis, either after magnetic separation of CD34+ cells (group 1) or starting from whole blood (group 2). Serum concentrations of VEGF and NO metabolites were measured using ELISA. Following exercise, EPC increased with 76% (15.4 ± 10.7 cells/ml vs. 27.2 ± 13.7 cells/ml, p=0.01) in group 1 and with 69% in group 2 (30.9 ± 14.6 cells/ml vs. 52.5 ± 42.6 cells/ml, p= 0.03). The increase in EPC correlated positively with LDL cholesterol and total cholesterol/HDL cholesterol ratio and negatively with VO2peak and VO2 at anaerobic threshold. VEGF levels increased with exercise with a strong trend towards significance (p=0.055). NO levels remained unchanged. The present study demonstrates that a maximal bout of exercise induces a significant shift in CD34+ cells towards CD34+/KDR+ cells. This response was larger in subjects with a less favourable lipid profile.
