Myoblasts transplanted into rat infarcted myocardium are functionally isolated from their host.
Survival and differentiation of myogenic cells grafted into infarcted myocardium have raised the hope that cell transplantation becomes a new therapy for cardiovascular diseases. The approach was further supported by transplantation of skeletal myoblasts, which was shown to improve cardiac performance in several animal species. Despite the success of myoblast transplantation and its recent trial in human, the mechanism responsible for the functional improvement remains unclear. Here, we used intracellular recordings coupled to video and fluorescence microscopy to establish whether myoblasts, genetically labeled with enhanced GFP and transplanted into rat infarcted myocardium, retain excitable and contractile properties, and participate actively to cardiac function. Our results indicate that grafted myoblasts differentiate into peculiar hyperexcitable myotubes with a contractile activity fully independent of neighboring cardiomyocytes. We conclude that mechanisms other than electromechanical coupling between grafted and host cells are involved in the improvement of cardiac function.
Leobon
Bertrand
B
Laboratory of Neurophysiology, Institut National de la Santé et de la Recherche Médicale, EPI 0002, Centre National de la Recherche Scientifique FRE2500, Ecole Supérieure de Physique et Chimie Industrielles de la Ville de Paris, 75231 Paris, France.
Garcin
Isabelle
I
Menasche
Philippe
P
Vilquin
Jean-Thomas
JT
Audinat
Etienne
E
Charpak
Serge
S
D000818:Animals; D000831:Animals, Newborn; D002454:Cell Differentiation; D017690:Cell Transplantation; D002478:Cells, Cultured; D004594:Electrophysiology; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D018715:Microscopy, Video; D018482:Muscle, Skeletal / Q000166:cytology; D009132:Muscles / Q000378:metabolism / Q000502:physiology; D032446:Myoblasts / Q000166:cytology* / Q000502:physiology*; D032448:Myoblasts, Skeletal / Q000166:cytology*; D009203:Myocardial Infarction / Q000378:metabolism*; D009206:Myocardium / Q000473:pathology*; D051381:Rats; D017208:Rats, Wistar; D014184:Transplantation, Homologous
D008164:Luminescent Proteins; D049452:Green Fluorescent Proteins