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Ex‐vivo testing and preclinical heterotopic thoracic cardiac xenotransplantation of multi‐transgenic organs
Author(s) -
Abicht JanMichael,
Mayr Tanja,
Guethoff Sonja,
Buchholz Stefan,
Werner Fabian,
Baehr Andrea,
Klymiuk Nikolai,
Wuensch Annegret,
Wolf Eckhart,
Belka Claus,
Ayares David,
Petersen Björn,
Niemann Heiner,
Bongoni Anjan K.,
Rieben Robert,
McGregor Christopher,
Reichart Bruno,
Brenner Paolo
Publication year - 2014
Publication title -
xenotransplantation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.052
H-Index - 61
eISSN - 1399-3089
pISSN - 0908-665X
DOI - 10.1111/xen.12083_14
Subject(s) - xenotransplantation , ex vivo , medicine , transgene , in vivo , genetically modified mouse , transplantation , pathology , biology , microbiology and biotechnology , gene , biochemistry
The heterotopic thoracic pig‐to‐baboon heart transplantation has been established by our group as a safe preclinical model. Since the recipient's own heart remains in place, it is possible to evaluate immunological reactions of various types and the symptoms of the thrombotic microangiopathy under working heart conditions. However, these experiments are complex and costly. In order to limit the number of transplants, we tested our multi‐transgenic porcine donor hearts in an ex‐vivo perfusion model first. Ex‐vivo model: Both beating ventricles were perfused with heparinized freshly drawn human whole blood using a centrifugal pump and a membrane oxygenator. During 3 h of observation, cardiac function parameters were obtained continuously; specimens from the perfusate, coronary sinus blood, and myocardial biopsies were assessed. Various genetically modified porcine donor hearts were tested; we are currently evaluating the impact of human thrombomodulin on the porcine microcirculation; the efficacy of complement regulation is another work package. Pig‐to‐baboon heterotopic cardiac xenotransplantation: In our latest group, seven baboons received five double (Gal‐KO/hCD46), and two triple (Gal‐KO/hCD46/hTM resp./HLA‐E) transgenic pig hearts. Our immunosuppressive regimen included preoperative anti‐CD20‐antibody, bortezomib, dexamethasone and cyclophosphamide; postoperatively, ATG, tacrolimus, MMF, anti‐CD20‐antibody, bortezomib and dexamethasone were administered. Total lymph node irradiation (6 Gy) was applied on postoperative day five. The triple transgenic hearts survived 35 and 37 days respectively. Both hearts maintained function throughout the experiment. Both recipients succumbed to fungal infections. Humoral rejection was seen only once. The next barrier appears to be the complex event of thrombotic microangiopathy that needs to be addressed with the additional expression of human thrombomodulin strategies.