Enhanced external counterpulsation promotes growth cytokines-mediated myocardial angiogenesis in a porcine model of hypercholesterolemia.
BACKGROUND
Enhanced external counterpulsation (EECP) improves ischemia in patients with refractory angina pectoris, but the mechanism remains unclear. To explore the mechanisms of EECP action, we detected progenitor cells presenting any of the following markers CD34(+), CD29(+), and CD106(+).


METHODS
Growth cytokines-mediated progenitor cell mobilization and associated angiogenesis potential were assessed in a porcine model of hypercholesterolemia. Twenty-four male domestic swines were randomly assigned to 4 groups: normal diet (control, n = 6), hypercholesterolemic diet (CHOL, n = 6), hypercholesterolemic diet with administration of recombinant human granulocyte colony-stimulating factor (rhG-CSF) (rhG-CSF, n = 6), and hypercholesterolemic diet with EECP treatment (EECP, n = 6). EECP was applied 2 hours every other day for a total of 36 hours. Serum levels of vascular endothelial growth factor (VEGF) and granulocyte colony-stimulating factor (G-CSF), peripheral blood progenitor cell counts, level of regional angiogenesis, and expression of VEGF and stromal cell derived factor 1alpha (SDF-1alpha) in porcine myocardium were assessed, respectively.


RESULTS
A porcine model of hypercholesterolemia-induced arteriosclerosis was successfully established. There was no significant difference in serum levels of VEGF among the four groups. The serum levels of G-CSF in the EECP group increased significantly at week 15 and week 18 ((38.3 +/- 5.6) pg/ml at week 15 vs (26.2 +/- 3.7) pg/ml at week 12, P < 0.05, and (46.9 +/- 6.1) pg/ml at week 18 vs (26.2 +/- 3.7) pg/ml at week 12, P < 0.01). The serum levels of G-CSF in group 3 increased also significantly after receiving rhG-CSF injection for five days ((150 +/- 13.9) pg/ml at week 18 vs (24.8 +/- 5.4) pg/ml at week 12, P < 0.01). Compared to other groups and other time points, progenitor cell counts increased significantly after 2-hour EECP treatment (108 +/- 13 vs 26 +/- 6 per 10(5) leukocytes, P < 0.01), but not at week 18. The progenitor cell counts also increased significantly after subcutaneous injection of rhG-CSF for five days compared to the week 12 (baseline) (180 +/- 21 vs 25 +/- 7 per 10(5) leukocytes, P < 0.01). There was no significant difference among the four groups at other time points. Moreover, the expression of VEGF and SDF-1alpha and the level of regional angiogenesis in myocardium increased significantly in both EECP and rhG-CSF groups.


CONCLUSIONS
The results demonstrated that EECP could facilitate angiogenesis in the myocardium of atherosclerotic swines by increasing endogenous G-CSF, inducing an enhanced mobilization of progenitor cells and augmenting myocardial expression of VEGF and SDF-1alpha.
Luo
Jing-yun
JY
Division of Cardiology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China.
Wu
Gui-fu
GF
Xiong
Yan
Y
Chen
Guo-wei
GW
Xie
Qiang
Q
Yang
Da-ya
DY
He
Xiao-hong
XH
Zhang
Yan
Y
Liu
Dong-hong
DH
Wang
Kui-jian
KJ
Ma
Hong
H
Zheng
Zhen-sheng
ZS
DU
Zhi-min
ZM
D000818:Animals; D001161:Arteriosclerosis / Q000503:physiopathology*; D015153:Blotting, Western; D054377:Chemokine CXCL12 / Q000378:metabolism; D015908:Counterpulsation / Q000379:methods*; D004195:Disease Models, Animal; D004591:Electrophoresis, Polyacrylamide Gel; D016179:Granulocyte Colony-Stimulating Factor / Q000097:blood / Q000378:metabolism; D006801:Humans; D006937:Hypercholesterolemia / Q000378:metabolism / Q000601:surgery*; D007150:Immunohistochemistry; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D009389:Neovascularization, Pathologic / Q000378:metabolism* / Q000601:surgery*; D011897:Random Allocation; D011994:Recombinant Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000166:cytology; D013552:Swine; D042461:Vascular Endothelial Growth Factor A / Q000097:blood / Q000378:metabolism
D054377:Chemokine CXCL12; D011994:Recombinant Proteins; D042461:Vascular Endothelial Growth Factor A; D016179:Granulocyte Colony-Stimulating Factor