First experience with heterotopic thoracic pig-to-baboon cardiac xenotransplantation.
BACKGROUND
Heterotopic thoracic heart transplantation may be an alternative to the established heterotopic abdominal or orthotopic cardiac xenotransplantation model as it combines the safety of heterotopic transplantation with the benefit of a working heart model.


METHODS
In a first series of two animals, we tested the surgical feasibility of this procedure with non-transgenic pig hearts transplanted into pre-sensitized baboons (killed after weaning from cardiopulmonary bypass). In a second group (n = 2), double-transgenic alpha(1,3)galactosyl-transferase knock out/hCD46 pig hearts were transplanted into naïve baboons after immunoadsorption. The immunosuppressive regimen consisted of anti-CD20-mAb, tacrolimus, sirolimus, MMF and steroids.


RESULTS
The first baboon was successfully transplanted, but died of an air embolism, while in the second animal graft survival was 50 days with the recipient in good physical condition. One rejection reaction was successfully treated by immunoadsorption, ATG and the proteasome inhibitor bortezomib. Post-mortem histopathology showed no evidence for humoral or cellular rejection of the cardiac xenograft.


CONCLUSIONS
This is the first description of a heterotopic thoracic pig-to-baboon heart transplantation. The procedure combines the advantages of a working heart model with the safety of heterotopic transplantation. In contrast to orthotopic transplantation, the recipient heart can assist the donor heart during episodes of rejection. We believe that the heterotopic thoracic model may accelerate the progress into the clinical application of cardiac xenotransplantation. However, successful combination of this heterotopic transplantation with an experimental model of cardiac failure may be needed before this technique can be promoted to clinical trials.
Bauer
Andreas
A
Department of Anaesthesiology, Ludwig Maximilian University Munich, Munich, Germany. andreas.bauer@med.uni-muenchen.de
Postrach
Johannes
J
Thormann
Michael
M
Blanck
Stefanie
S
Faber
Claudius
C
Wintersperger
Bernd
B
Michel
Sebastian
S
Abicht
Jan-Michael
JM
Christ
Frank
F
Schmitz
Christoph
C
Schmoeckel
Michael
M
Reichart
Bruno
B
Brenner
Paolo
P
D000818:Animals; D055785:Gene Knockdown Techniques; D006084:Graft Rejection / Q000188:drug therapy* / Q000473:pathology; D006085:Graft Survival; D016027:Heart Transplantation / Q000379:methods* / Q000473:pathology; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D051916:Membrane Cofactor Protein / Q000235:genetics; D009206:Myocardium / Q000473:pathology; D010215:Papio; D013552:Swine; D014183:Transplantation, Heterologous / Q000379:methods* / Q000473:pathology
D007166:Immunosuppressive Agents; D051916:Membrane Cofactor Protein