title: In vivo optical bioluminescence imaging of collagen-supported cardiac cell grafts.
abstract: BACKGROUND
  Histology-based survival assessment of cell grafts does not allow for in vivo follow-up. In this study we introduce two new experimental models for longitudinal in vivo survival studies of cardiac cell grafts using optical bioluminescence imaging.
  
  
  METHODS
  H9c2 cardiomyoblasts expressing both firefly luciferase (fluc) and green fluorescent protein (GFP) reporter genes were implanted into Lewis rats. In Model 1, H9c2-fluc-IRES-GFP cells (0.5 x 10(6)) were implanted into a cryoinjured abdominal wall muscle. Cells were injected using either liquid collagen (Matrigel [MG]) or phosphate-buffered saline (PBS) suspension. Cell survival was evaluated in vivo using bioluminescence imaging on days 1, 5 and 10 post-operatively. In model 2, rats underwent ligation of the left anterior descending (LAD) artery. The donor hearts were harvested, and the infarcted region was restored ex situ using 1 x 10(6) H9c2-fluc-IRES-GFP cells seeded in collagen matrix (Gelfoam [GF]) or suspended in PBS (n = 8/group). Hearts were then transplanted into the abdomen of syngeneic recipients. Optical bioluminescence imaging was performed on Days 1, 5, 8 and 14 post-operatively. After 4 weeks, immunohistologic studies were performed.
  
  
  RESULTS
  For model 1, at day 5, bioluminescence signals were markedly higher for the H9c2/MG group (449 +/- 129 photons/second x 10(3)) compared with the H9c2/PBS group (137 +/- 82 photons/second x 10(3)) (p < 0.05). For model 2, bioluminescence signals were significantly (p < 0.04) higher in the H9c2/GF group compared with plain cell injection on days 5 (534 +/- 115 vs 219 +/- 34) and 8 (274 +/- 34 vs 180 +/- 23). Data were in accordance with GFP immunohistology.
  
  
  CONCLUSIONS
  Optical bioluminescence is a powerful method for assessment of cardiac cell graft survival in vivo. Collagen matrices support early survival of cardiomyoblasts after transplantation into injured musculature.
authors.affiliation: Department of Cardiothoracic Surgery, Stanford University School of Medicine, Stanford, California, USA. ingo.kutschka@t-online.de
authors.forename: Ingo
authors.initials: I
authors.lastname: Kutschka
authors.forename: Ian Y
authors.initials: IY
authors.lastname: Chen
authors.forename: Theo
authors.initials: T
authors.lastname: Kofidis
authors.forename: Georges
authors.initials: G
authors.lastname: von Degenfeld
authors.forename: Ahmad Y
authors.initials: AY
authors.lastname: Sheikh
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Hendry
authors.forename: Grant
authors.initials: G
authors.lastname: Hoyt
authors.forename: Jeremy
authors.initials: J
authors.lastname: Pearl
authors.forename: Helen M
authors.initials: HM
authors.lastname: Blau
authors.forename: Sanjiv S
authors.initials: SS
authors.lastname: Gambhir
authors.forename: Robert C
authors.initials: RC
authors.lastname: Robbins
mesh_terms: D000009:Abdominal Muscles / Q000601:surgery*; D000818:Animals; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D003094:Collagen / Q000008:administration & dosage* / Q000494:pharmacology; D003952:Diagnostic Imaging; D004338:Drug Combinations; D049452:Green Fluorescent Proteins; D016027:Heart Transplantation; D007267:Injections; D007797:Laminin / Q000008:administration & dosage* / Q000494:pharmacology; D049409:Luciferases, Firefly; D049408:Luminescent Agents; D008297:Male; D032386:Myoblasts, Cardiac / Q000637:transplantation*; D009203:Myocardial Infarction / Q000601:surgery*; D055095:Optics and Photonics; D011509:Proteoglycans / Q000008:administration & dosage* / Q000494:pharmacology; D051381:Rats; D011917:Rats, Inbred Lew; D013997:Time Factors; D016042:Transplantation, Heterotopic; D014185:Transplantation, Isogeneic
chemical_list: D004338:Drug Combinations; D007797:Laminin; D049408:Luminescent Agents; D011509:Proteoglycans; C059485:matrigel; D049452:Green Fluorescent Proteins; D003094:Collagen; D049409:Luciferases, Firefly