title: Mobilization and homing of bone marrow stromal cells in myocardial infarction.
abstract: OBJECTIVE
  Marrow stromal cells (MSCs) contain multipotent cells, which may participate in the repair of damaged organs. We tested the hypothesis that MSCs are recruited to the heart upon myocardial infarction (MI), and play pathophysiological roles in the healing and adaptation process.
  
  
  METHODS
  Donor MSCs from isogenic Lewis rats were harvested, multiplied and labeled with Lac Z reporter gene. Ten million labeled cells were injected intravenously into the recipient rats (n=30). One week later, 10 rats were killed to examine the distribution of the labeled MSCs. Other rats underwent either coronary artery ligations (n=14) or sham operations (n=6). The hearts were removed at various time points (1-8 weeks) and stained for beta-galactosidase activity. Phenotypes of labeled cells were identified with immunohistochemical stains.
  
  
  RESULTS
  In rats killed at 1 week, labeled cells had homed into the bone marrow of the recipients, and none found in their hearts. In the coronary ligated hearts, labeled cells were seen in and near the infarct at all time points studied (14/14), but none in the sham operated hearts (6/6). There was evidence for myogenic differentiation. Some of these labeled cells showed positive staining for cardiomyocyte specific troponin I-c at 4 weeks, while others appeared in the vascular walls expressing smooth muscle alpha-actin.
  
  
  CONCLUSIONS
  Following myocardial infarction, MSC's are signaled and recruited to the injured heart, where they undergo differentiation, and may participate in the pathophysiology of post-infarct remodeling, angiogenesis, and maturation of the scar. Therapeutic implantation of MSCs thus may further enhance such effects.
authors.affiliation: Division of Cardiothoracic Surgery, McGill University Health Center, Montreal, Quebec, Canada.
authors.forename: Bindu
authors.initials: B
authors.lastname: Bittira
authors.forename: Dominique
authors.initials: D
authors.lastname: Shum-Tim
authors.forename: Abdulaziz
authors.initials: A
authors.lastname: Al-Khaldi
authors.forename: Ray C-J
authors.initials: RC
authors.lastname: Chiu
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000502:physiology*; D016026:Bone Marrow Transplantation; D002454:Cell Differentiation; D002465:Cell Movement; D002478:Cells, Cultured; D003326:Coronary Circulation; D008297:Male; D009203:Myocardial Infarction / Q000473:pathology* / Q000503:physiopathology; D032383:Myocytes, Cardiac / Q000473:pathology; D009389:Neovascularization, Pathologic / Q000473:pathology / Q000503:physiopathology; D051381:Rats; D011917:Rats, Inbred Lew; D017154:Stromal Cells / Q000502:physiology / Q000637:transplantation