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TRR 127:  Biology of Xenogeneic Cell and Organ Transplantation - From Bench to Bedside

Subject Area Biology
Agriculture, Forestry and Veterinary Medicine
Medicine
Social and Behavioural Sciences
Term from 2012 to 2024
Website Homepage
Project identifier Deutsche Forschungsgemeinschaft (DFG) - Project number 213602983
 
The TRR 127 aims to dissect the biology of xenogeneic cell, tissue and organ transplantation and develops evidence-based concepts that bring xenotransplantation of porcine pancreatic islets, heart valves, and hearts from bench to bedside. Three closely interacting Project Groups A, B and C are supported by the Central Project Group Z that focuses on ethical, legal and societal issues (Z1), microbiological safety (Z2), provision of safe donor pigs with effective and stable genetic modifications (Z3), and non-human primate (NHP) studies (Z4). Project Group A is developing concepts to modulate immune mechanisms at the xenograft-host interface. This includes i) downregulation of swine leukocyte antigens (SLA) and selection of suitable donor-recipient combinations by SLA-HLA (H = human) matching (A1); ii) local immunomodulation by recombinant adeno-associated viral vectors (rAAV), micro-RNAs, or small hairpin (sh) RNAs (A2); and iii) mechanisms of the instant blood-mediated inflammatory reaction after intraportal islet transplantation (A3, A5). In addition, protocols for Treg-mediated tolerance induction will be established (A4).Project Group B is developing and characterising genetically multi-modified donor pigs. Pigs carrying hCD46, hCD55, hCD59, hHO1 and hA20 expression vectors (5tg) will be combined with 4ko pigs that lack SLA class I, GGTA1, CMAH and B4GALNT2 to provide multi-modified pigs for transplantation of xeno-hearts and heart valves (B1&2). Pigs that lack GGTA1 and CCL2 and express LEA29Y, hPD-L1 and hCD47 (2ko, 3tg) are produced as optimised donors of xeno-islets. Single-cell RNA sequencing will be employed to inform and improve methods of maturing neonatal porcine islets (NPIs) (B3).Project Group C will perform preclinical xenotransplantation experiments and develop clinical study protocols. The optimal age and maturation stage of NPIs will be refined and their functionality tested (C1). For intraportal free islet transplantation, NPIs with different combinations of genetic modifications will be used in diabetic NHPs with novel immunosuppressive strategies (C3). A clinical study protocol for macroencapsulated porcine islets has been submitted; this approach will be further optimised employing cutting-edge bio-polymer technologies (C4). Successful efforts to generate haemodynamically effective, immunocompatible xenogeneic pulmonary heart valves from GGTA1/CMAH/B4GALNT2-3ko pigs will be extended using advanced decellularisation and deglycosylation techniques (C7). The world’s first consistent long-term success after orthotopic xenotransplantation of GGTA1-ko, hCD46/hTBM-2tg pig hearts in baboons required perfusion with cold, hyperoncotic, oxygenated preservation solution, appropriate immunosuppression, and medication to prevent overgrowth of the xeno-hearts. In future experiments, hearts from 4ko, 5tg pigs will be tested in the orthotopic transplantation model in baboons with improved immunosuppressive regimens (C8).
DFG Programme CRC/Transregios

Completed projects

Spokespersons Professor Dr. Bruno Reichart, until 6/2016; Professor Dr. Eckhard Wolf, since 7/2017
 
 

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