title: Intra-vital fluorescence microscopy for intra-myocardial graft detection following cell transplantation.
abstract: BACKGROUND
  The aim of our study was the development of a potentially clinically applicable approach, which allows for intra-myocardial detection of the transplanted cells without the need for collection of tissue samples. Intra-myocardial transplantation of myocytes and bone marrow derived cells is currently under clinical evaluation as a therapy of heart failure. A major limitation of all clinical studies for myocardial restoration through cell transfer is the inability to track the fate of the transplanted cells.
  
  
  METHODS
  Fetal canine cardiomyocytes were labelled with the non-toxic fluorescent membrane dye Vybrant CM-DiI and injected into the free wall of the left ventricle of six adult mongrel dogs. For subsequent tracking of the cellular graft, the dogs were re-operated and an intra-vital microscope was mounted above the exposed heart within the thorax.
  
  
  RESULTS
  Two months following cell transplantation, the fluorescent graft was visible by intra-vital microscopy using a 10x magnification. Histological studies served as microscopic control and confirmed the presence of DiI-labelled cells at the site of injection. Connexin 43 immunoreactivity was visible at junctional complexes between donor and recipient cells, suggesting morphologic coupling as a result of gap junction formation.
  
  
  CONCLUSIONS
  Our results demonstrate that in vivo detection of transplanted cells in the heart is feasible. Further technical adjustments will facilitate thoracoscopic and therefore less invasive application of this method.
authors.affiliation: The Department of Thoracic- and Cardiovascular Surgery, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany. ruhparwar@thg.mh-hanover.de
authors.forename: Arjang
authors.initials: A
authors.lastname: Ruhparwar
authors.forename: Theo
authors.initials: T
authors.lastname: Kofidis
authors.forename: Nicole
authors.initials: N
authors.lastname: Ruebesamen
authors.forename: Matthias
authors.initials: M
authors.lastname: Karck
authors.forename: Axel
authors.initials: A
authors.lastname: Haverich
authors.forename: Ulrich
authors.initials: U
authors.lastname: Martin
mesh_terms: D000818:Animals; D002232:Carbocyanines; D018031:Connexin 43 / Q000378:metabolism; D004285:Dogs; D005240:Feasibility Studies; D005456:Fluorescent Dyes; D007091:Image Processing, Computer-Assisted; D008856:Microscopy, Fluorescence; D023421:Models, Animal; D009206:Myocardium / Q000166:cytology* / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000637:transplantation*
chemical_list: C101089:CM-DiI; D002232:Carbocyanines; D018031:Connexin 43; D005456:Fluorescent Dyes