Effects of endothelin-1 on endothelial progenitor cell function.
BACKGROUND
Circulating endothelial progenitor cells (EPCs) contribute to vascular endothelial repair. Endothelin (ET)-1 is associated with endothelial damage and atherogenesis. The experimental aim of this study was to determine, in vitro, the effects of ET-1 on the ability of EPCs to form colonies, migrate, release angiogenic growth factors and resist apoptosis.


METHODS
Peripheral blood samples were collected from 10 healthy adult humans. Cells with phenotypic EPC characteristics were isolated and EPC colony-forming capacity (CFU assay), migratory activity (Boyden chamber), release of angiogenic growth factors (enzyme immunoassay) and apoptosis (TUNEL assay) were determined in the absence and presence of ET-1 (100 pmol).


RESULTS
EPC colony-forming units (42±12 vs. 39±11), migratory capacity (910±146 vs. 936±148 AU) and release of vascular endothelial growth factor (202.8±68.1 vs. 204.8±69.8 pg/mL) and granulocyte-colony stimulating factor (1294.4±378.3 vs. 1136.1±310.3 pg/mL) were not significantly affected by ET-1. EPCs treated with ET-1 demonstrated a 20% increase (p<0.05) in cellular apoptosis. The proapoptotic effect of ET-1 was abolished with ET receptor blockade as well as with apocynin, a nicotinamide adenine dinucleotide phosphate (NADPH) inhibitor.


CONCLUSIONS
These results indicate that ET-1 does not affect EPC colony formation, migratory capacity or angiogenic growth factor release, but does increase EPC susceptibility to apoptosis through an NADPH-dependent mechanism. Increased EPC apoptosis may contribute to the proatherogenic effects of ET-1.
Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado, Boulder, CO, USA.
Kyle J
KJ
Diehl
Brian R
BR
Weil
Christian M
CM
Westby
Owen J
OJ
MacEneaney
Erich J
EJ
Kushner
Jared J
JJ
Greiner
Christopher A
CA
DeSouza
D000328:Adult; D017209:Apoptosis / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D019332:Endothelin-1 / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000166:cytology*; D006801:Humans; D013234:Stem Cells / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D055815:Young Adult
D019332:Endothelin-1; D042461:Vascular Endothelial Growth Factor A