title: Age-dependent depression in circulating endothelial progenitor cells in patients undergoing coronary artery bypass grafting.
abstract: OBJECTIVE
  The effect of patient age on circulating endothelial progenitor cells (EPCs) and their mobilization during coronary artery bypass grafting (CABG) was assessed.
  
  
  BACKGROUND
  The EPCs are able to contribute to reparative neovascularization after tissue ischemia. In experimental models, reparative neovascularization is impaired in senescent animals, but the role of EPCs in this impairment, especially in humans, is unknown.
  
  
  METHODS
  In 50 consecutive patients (43 to 80 years old) with stable coronary artery disease undergoing CABG, the numbers of EPCs and the plasma levels of interleukin (IL)-6, IL-8, IL-10, and IL-18, as well as vascular endothelial growth factor (VEGF) and placental growth factor, were determined preoperatively, after coming off bypass, and 6, 12, 24, and 72 h postoperatively.
  
  
  RESULTS
  Preoperative values of EPCs were lowered with increasing age, similar to the lowering of plasma VEGF levels. These age-associated decreases could not be explained by differences in atherosclerotic risk factors or cardiac function. Bypass surgery induced a rapid mobilization in EPCs, IL-6, IL-8, IL-10, and VEGF, with a peak 6 h postoperatively. Persistently lower levels of EPCs and VEGF throughout the observation period were observed in patients >69 years old, which could not be explained by differences in the operative procedure or inflammatory IL activation.
  
  
  CONCLUSIONS
  Despite a significant increase in EPCs and release of cytochemokines during CABG, age is a major limiting factor for mobilization of EPCs. Further studies are necessary to improve the strategies for mobilization, ex vivo expansion, and re-transplantation of EPCs in aging patients.
authors.affiliation: Department of Cardiothoracic Surgery, and Institute of Epidemiology, Biostatistics and Informatics, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany. robert.schuebel@medizin.uni-halle.de
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Scheubel
authors.forename: Holger
authors.initials: H
authors.lastname: Zorn
authors.forename: Rolf-Edgar
authors.initials: RE
authors.lastname: Silber
authors.forename: Oliver
authors.initials: O
authors.lastname: Kuss
authors.forename: Henning
authors.initials: H
authors.lastname: Morawietz
authors.forename: Juergen
authors.initials: J
authors.lastname: Holtz
authors.forename: Andreas
authors.initials: A
authors.lastname: Simm
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001026:Coronary Artery Bypass; D003327:Coronary Disease / Q000601:surgery; D004730:Endothelium, Vascular / Q000166:cytology*; D005260:Female; D006801:Humans; D016753:Interleukin-10 / Q000097:blood; D020382:Interleukin-18 / Q000097:blood; D015850:Interleukin-6 / Q000097:blood; D016209:Interleukin-8 / Q000097:blood; D008297:Male; D008875:Middle Aged; D000072483:Placenta Growth Factor; D011257:Pregnancy Proteins / Q000097:blood; D013234:Stem Cells / Q000166:cytology*; D042461:Vascular Endothelial Growth Factor A / Q000097:blood
chemical_list: D020382:Interleukin-18; D015850:Interleukin-6; D016209:Interleukin-8; C000608036:PGF protein, human; D011257:Pregnancy Proteins; D042461:Vascular Endothelial Growth Factor A; D016753:Interleukin-10; D000072483:Placenta Growth Factor