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Dissecting the instant blood‐mediated inflammatory reaction in islet xenotransplantation
Author(s) -
Goto Masafumi,
Tjernberg Jenny,
Dufrane Denis,
Elgue Graciela,
Brandhorst Daniel,
Ekdahl Kristiilsson,
Brandhorst Heidi,
Wennberg Lars,
Kurokawa Yoshimochi,
Satomi Susumu,
Lambris John D.,
Gianello Pierre,
Korsgren Olle,
Nilsson Bo
Publication year - 2008
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/j.1399-3089.2008.00482.x
Subject(s) - xenotransplantation , islet , complement system , transplantation , in vivo , in vitro , immunology , immune system , biology , chemistry , medicine , endocrinology , biochemistry , diabetes mellitus , microbiology and biotechnology
Background: A massive destruction of transplanted tissue occurs immediately following transplantation of pancreatic islets from pig to non‐human primates. The detrimental instant blood‐mediated inflammatory reaction (IBMIR), triggered by the porcine islets, is a likely explanation for this tissue loss. This reaction may also be responsible for mediating an adaptive immune response in the recipient that requires a heavy immunosuppressive regimen. Materials and methods: Low molecular weight dextran sulfate (LMW‐DS) and the complement inhibitor Compstatin were used in a combination of in vitro and in vivo studies designed to dissect the xenogeneic IBMIR in a non‐human primate model of pancreatic islet transplantation. Adult porcine islets (10 000 IEQs/kg) were transplanted intraportally into three pairs of cynomolgus monkeys that had been treated with LMW‐DS or heparin (control), and the effects on the IBMIR were characterized. Porcine islets were also incubated in human blood plasma in vitro to assess complement inhibition by LMW‐DS and Compstatin. Results: Morphological scoring and immunohistochemical staining revealed that the severe islet destruction and macrophage, neutrophilic granulocyte, and T‐cell infiltration observed in the control (heparin‐treated) animals were abrogated in the LMW‐DS‐treated monkeys. Both coagulation and complement activation were significantly reduced in monkeys treated with LMW‐DS, but IgM and complement fragments were still found on the islet surface. This residual complement activation could be inhibited by Compstatin in vitro. Conclusions: The xenogeneic IBMIR in this non‐human primate model is characterized by an immediate binding of antibodies that triggers deleterious complement activation and a subsequent clotting reaction that leads to further complement activation. The effectiveness of LMW‐DS (in vivo and in vitro) and Compstatin (in vitro) in inhibiting this IBMIR provides the basis for a protocol that can be used to abrogate the IBMIR in pig‐human clinical islet transplantation.