title: Bone marrow resident and circulating progenitor cells in patients undergoing cardiac surgery.
abstract: BACKGROUND
  Vascular trauma induced by surgical revascularization stimulates mobilization of hematopoietic and nonhematopoietic progenitor cells. However, it is not clear whether mobilized progenitors are functionally active and participate in peripheral homing. We have found no clinical studies available regarding the reaction of bone marrow to surgical revascularization.
  
  
  METHODS
  This was an observational prospective study of 76 patients undergoing elective coronary artery bypass graft surgery. Bone marrow aspirates and blood samples were collected at baseline, at the end of surgery, and 24 hours postoperatively (blood samples only). The CD34+, CD34+CD133+, and CD34+CXCR4+ progenitor cell counts, CXCR4+ mononuclear cell counts, and CXCR4 expression on CD34+ cells were measured by flow cytometry. Progenitor cell functions were studied in vitro by clonogenic and migration assays.
  
  
  RESULTS
  In response to coronary revascularization there was mobilization of CD34+ progenitors, having increased migratory and clonogenic function. The CD34+CXCR4+ subsets and CXCR4 expression on CD34+ cells in peripheral blood increased significantly 24 hours postoperatively. The CXCR4 expression on mobilized progenitors at the end of surgery was independently related to baseline CXCR4 expression on bone marrow resident CD34+ cells and duration of cardiopulmonary bypass in a multivariate model. At the end of surgery there was a significant fall in the expression of CXCR4 on CD34+ bone marrow cells, suggesting egress into peripheral circulation of the most active CXCR4-expressing progenitors.
  
  
  CONCLUSIONS
  Coronary artery bypass graft surgery is associated with bone marrow release of functionally active progenitor cells. Further studies are needed to verify whether mobilized progenitors participate in regeneration of injured tissues.
authors.affiliation: Department of Cardiothoracic Surgery, Cardiac and Vascular Sciences, St. George's Hospital, University of London, London, United Kingdom.
authors.forename: Olena
authors.initials: O
authors.lastname: Dotsenko
authors.forename: Qingzhong
authors.initials: Q
authors.lastname: Xiao
authors.forename: Qingbo
authors.initials: Q
authors.lastname: Xu
authors.forename: Marjan
authors.initials: M
authors.lastname: Jahangiri
mesh_terms: D000368:Aged; D018952:Antigens, CD34 / Q000097:blood / Q000276:immunology; D001854:Bone Marrow Cells / Q000166:cytology* / Q000276:immunology; D001026:Coronary Artery Bypass; D003324:Coronary Artery Disease / Q000097:blood / Q000276:immunology / Q000601:surgery*; D003331:Coronary Vessels / Q000502:physiology*; D005260:Female; D005434:Flow Cytometry; D005500:Follow-Up Studies; D006801:Humans; D007111:Immunity, Cellular; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D019718:Receptors, CXCR4 / Q000096:biosynthesis / Q000276:immunology; D012038:Regeneration / Q000502:physiology*; D013234:Stem Cells / Q000166:cytology*
chemical_list: D018952:Antigens, CD34; C527276:CXCR4 protein, human; D019718:Receptors, CXCR4