Habitual physical activity is associated with endothelial function and endothelial progenitor cells in patients with stable coronary artery disease.
BACKGROUND
Exercise training reduces mortality in patients with coronary artery disease (CAD); however, the impact of habitual physical activity level (PAL) on vascular endothelial function and circulating endothelial progenitor cells (EPCs) remain unknown.


METHODS
We assessed habitual PAL using a validated International Physical Activity Questionnaire in 116 patients (67.8+/-9.5 years; 81% male) with stable CAD and preserved left ventricular ejection fraction > or =45%. The number of circulating CD34/KDR+ and CD133/KDR+ EPCs was determined by flow cytometry, and brachial artery flow-mediated dilation (FMD) was measured.


RESULTS
The mean PAL of CAD patients with 1644 MET min/week (where MET is metabolic equivalents). With higher habitual PAL tertiles, there were significant linear trends of increased FMD (P = 0.001) and CD133/KDR+ EPCs (P = 0.03), but not of CD34/KDR+ EPCs. Patients with the highest tertile of PAL were associated with an absolute increase of 1.89% in FMD (relative increase 68%, P = 0.003) and 0.12% in CD133/KDR+ EPCs (relative increase 44%, P = 0.01) compared with those in the lowest tertile of PAL, after adjusting for age, sex, presence of hypertension, diabetes mellitus, hypercholesterolemia, smoking, and the use of medications including statins. However, neither CD34/KDR+ nor CD133/KDR+ EPCs significantly correlated with FMD.


CONCLUSIONS
This study showed that higher habitual PAL in patients with CAD was associated with higher FMD and EPC count. Nonetheless, FMD only significantly correlated with increased PAL, but not EPC, suggesting that increased physical activity improves endothelial function through mechanisms other than increasing EPC count.
Luk
Ting-Hin
TH
Cardiology Division, Department of Medicine, The University of Hong Kong, Hong Kong, China.
Dai
Yuk-Ling
YL
Siu
Chung-Wah
CW
Yiu
Kai-Hang
KH
Chan
Hiu-Ting
HT
Fong
Daniel Yee-Tak
DY
Lee
Stephen W L
SW
Li
Sheung-Wai
SW
Tam
Sidney
S
Lau
Chu-Pak
CP
Tse
Hung-Fat
HF
D000368:Aged; D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood; D001783:Blood Flow Velocity; D016009:Chi-Square Distribution; D003324:Coronary Artery Disease / Q000503:physiopathology* / Q000534:rehabilitation*; D042783:Endothelial Cells / Q000502:physiology*; D004730:Endothelium, Vascular / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D016014:Linear Models; D008055:Lipids / Q000097:blood; D008297:Male; D012307:Risk Factors; D013234:Stem Cells / Q000502:physiology*; D011795:Surveys and Questionnaires; D014664:Vasodilation / Q000502:physiology
D015415:Biomarkers; D008055:Lipids