title: Persistence of marrow stromal cells implanted into acutely infarcted myocardium: observations in a xenotransplant model.
abstract: OBJECTIVE
  It has been reported that unmatched adult bone marrow stromal cells could be tolerated by immune-competent allotransplant or xenotransplant recipients under various conditions. This study examined whether xenogeneic bone marrow stromal cells implanted immediately after myocardial infarction can survive and differentiate, attenuating deterioration in left ventricular function.
  
  
  METHODS
  In groups I and II (n = 34), myocardial infarctions were created in immunocompetent adult Lewis rats by proximal left coronary artery ligation. In group I, 3 x 10(6)lacZ-labeled mouse bone marrow stromal cells were immediately injected into the peri-infarct area of the left ventricle, whereas in group II, only culture medium was injected. There were 10 early and 4 late deaths. At 4 weeks after injection, hearts were stained for beta-galactosidase and troponin IC. In groups IIIA and IIIB, lacZ-labeled mouse skin fibroblasts were implanted into rat myocardium (n = 10 each) with and without left coronary artery ligation, respectively, and the rats were killed serially. In group IV, animals underwent sham surgery (n = 5, no deaths). At 4 weeks, surviving rats in groups I, II, and IV (n = 10, n = 10, and n = 5, respectively) underwent blinded transthoracic echocardiography for ventricular function studies.
  
  
  RESULTS
  In group I, labeled mouse-derived bone marrow stromal cells were found within rat myocardium that stained positively for troponin IC 4 weeks after implantation. Functionally, mean left ventricular ejection fraction (P = .007), stroke volume (P = .03), and fractional shortening (P = .02) were all significantly higher in group I than in group II. In groups IIIA and IIIB, mouse fibroblasts induced cellular infiltration with rapid loss of donor cells. No labeled cells were found after 4 days. In group IV, there was no change in cardiac function.
  
  
  CONCLUSIONS
  Xenogeneic bone marrow stromal cells implanted into acutely ischemic myocardium induced by coronary artery ligation were immunologically tolerated, survived and differentiated, resulting in a cardiac chimera which improved left ventricular function. This unique immunologic tolerance may suggest the feasibility of using bone marrow stromal cells as universal donor cells.
authors.affiliation: Division of Cardiothoracic Surgery, McGill University Health Center, Montreal, Quebec, Canada.
authors.forename: Derek J
authors.initials: DJ
authors.lastname: MacDonald
authors.forename: Jun
authors.initials: J
authors.lastname: Luo
authors.forename: Takayuki
authors.initials: T
authors.lastname: Saito
authors.forename: Minh
authors.initials: M
authors.lastname: Duong
authors.forename: Pierre-Luc
authors.initials: PL
authors.lastname: Bernier
authors.forename: Ray C J
authors.initials: RC
authors.lastname: Chiu
authors.forename: Dominique
authors.initials: D
authors.lastname: Shum-Tim
mesh_terms: D000818:Animals; D016026:Bone Marrow Transplantation; D005260:Female; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009203:Myocardial Infarction / Q000601:surgery*; D051381:Rats; D011917:Rats, Inbred Lew; D017154:Stromal Cells / Q000637:transplantation*; D014183:Transplantation, Heterologous