Heterotopic Implantation of Fetal Heart in Syngeneic Adult Rats (Comparative Study of Growth Conditions, Limits and Perspectives) | Biomedgrid

Background: In spite of the official ending of the moratorium about foetus and foetal material use for scientific purpose, foetal organ transplantation remains weakly investigated though it represents a culture in vivo of developing cells, tissues, organs. The present work aims at exploring technical and developmental aspects of such a study applied to the foetal heart heterotopic implantation. Material and methods: 130 rats of both sexes and different strains (Wistar and Fischer) were used for syngeneic implantation of foetal heart into different sites (intra thoracic, intra peritoneal, subcutaneous) of adult organisms. The graft functional and morphological evolution was assessed by ultrasound, magnetic resonance, electrophysiology methods, trans-illumination, and optic and electron microscopy investigations. Observation delays ran up to 12 months. Results: In spite of uniformed implantation general conditions, graft survival and growth were hazardous and varied from 0 to 91% depending mainly on the implantation site. The best implant survival and development was observed in the ear pavilion subcutaneous site. An adult-like organ formed and was functional with morphologically normal cardiomyocytes. In the other sites development seemed to be slowed and remained incomplete, like stopped at an intermediary level. Conclusion: Heterotopic foetal heart implantation into syngeneic adult different sites is feasible in the rat but gives non-homogeneous results. The graft development was complete only when implantation was realized in an ear pavilion subcutaneous pouch. Anyway the fetal heart implants could not be proposed for reparative heart surgery: they are too distant from the pericardium cavity to be used as a vascularized flap. The causes and implications of these differences in development of foetal heart implants are worthwhile further investigations, as well as means of improving their growth.