Up to 9-day survival and control of thrombocytopenia following alpha1,3-galactosyl transferase knockout swine liver xenotransplantation in baboons.
BACKGROUND
With standard miniature swine donors, survivals of only 3 days have been achieved in primate liver-transplant recipients. The recent production of alpha1,3-galactosyl transferase knockout (GalT-KO) miniature swine has made it possible to evaluate xenotransplantation of pig organs in clinically relevant pig-to-non-human primate models in the absence of the effects of natural anti-Gal antibodies. We are reporting our results using GalT-KO liver grafts.


METHODS
We performed GalT-KO liver transplants in baboons using an immunosuppressive regimen previously used by our group in xeno heart and kidney transplantation. Post-operative liver function was assessed by laboratory function tests, coagulation parameters and histology.


RESULTS
In two hepatectomized recipients of GalT-KO grafts, post-transplant liver function returned rapidly to normal. Over the first few days, the synthetic products of the donor swine graft appeared to replace those of the baboon. The first recipient survived for 6 days and showed no histopathological evidence of rejection at the time of death from uncontrolled bleeding, probably caused by transfusion-refractory thrombocytopenia. Amicar treatment of the second and third recipients led to maintenance of platelet counts of over 40 000 per μl throughout their 9- and 8-day survivals, which represents the longest reported survival of pig-to-primate liver transplants to date. Both of the last two animals nevertheless succumbed to bleeding and enterococcal infection, without evidence of rejection.


CONCLUSIONS
These observations suggest that thrombocytopenia after liver xenotransplantation may be overcome by Amicar therapy. The coagulopathy and sepsis that nevertheless occurred suggest that additional causes of coagulation disturbance must be addressed, along with better prevention of infection, to achieve long-term survival.
Department of Surgery, Massachusetts General Hospital, Boston, MA, USA.
Karen
K
Kim
Christian
C
Schuetz
Nahel
N
Elias
Gregory R
GR
Veillette
Isaac
I
Wamala
Manish
M
Varma
R Neal
RN
Smith
Simon C
SC
Robson
A Benedict
AB
Cosimi
David H
DH
Sachs
Martin
M
Hertl
D000818:Animals; D005700:Galactosyltransferases / Q000037:antagonists & inhibitors* / Q000235:genetics; D055786:Gene Knockout Techniques; D006085:Graft Survival; D006801:Humans; D016031:Liver Transplantation / Q000009:adverse effects / Q000379:methods / Q000502:physiology; D008297:Male; D048529:Papio hamadryas; D013552:Swine; D013556:Swine, Miniature; D013921:Thrombocytopenia / Q000517:prevention & control; D013997:Time Factors; D014183:Transplantation, Heterologous / Q000009:adverse effects / Q000379:methods / Q000502:physiology
D005700:Galactosyltransferases