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- Brandhorst, Daniel, 1961-, et al.
(författare)
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Pancreas storage in oxygenated perfluorodecalin does not restore post-transplant function of isolated pig islets pre-damaged by warm ischemia
- 2006
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Ingår i: Xenotransplantation. - : Wiley. - 0908-665X .- 1399-3089. ; 13:5, s. 465-470
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Tidskriftsartikel (refereegranskat)abstract
- Background: Cold storage in oxygenated perfluorodecalin (PFD) restores transplant function of ischemically damaged dog pancreata and reduces the impact of cold ischemia on recovery of isolated human islets. Whether PFD storage can improve islet isolation from pancreata exposed to significant warm ischemia (WI) is unclear yet. The present study aimed to clarify this question in adult pigs. Methods: After exsanguination, the intestine was removed immediately or left in the cavity for 30 min of WI. Resected pancreata were intraductally flushed with cold University of Wisconsin solution. Subsequently, pancreata were processed immediately by digestion-filtration (group I: 0 min WI, n = 6; II: 30 min WI, n = 6) or first stored for 3 h in oxygenated PFD (III: 0 min WI + PFD, n = 5; IV: 30 min WI + PFD, n = 6). Results: Pancreata subjected to 30 min of WI yielded significantly less islets compared with the corresponding non-ischemic organs (I vs. II, P < 0.01; III vs. IV, P < 0.05). Oxygenation did not ameliorate the loss in islet yield (II vs. IV, NS). Ischemic islets were characterized by depleted ATP stores (388 +/- 73 (I) vs. 133 +/- 22 ng/1000 IEQ (II), P < 0.01) and diminished insulin response to glucose calculated as stimulation index (SI; 2.47 +/- 0.36 (I) vs. 0.25 +/- 0.17 (II), P < 0.05). PFD storage of ischemic organs partially restored ATP content (217 +/- 23 ng/1000 IEQ, II vs. IV, P < 0.05) and glucose SI (1.60 +/- 0.09, II vs. IV, P < 0.05) to a significant extent that reached the level of corresponding PFD-stored, non-ischemic pancreata (III vs. IV, NS). Sustained normoglycemia was exclusively observed in diabetic nude mice transplanted with islets isolated from non-ischemic organs. The significantly reduced graft function of ischemic islets (I vs. II, III vs. IV, P < 0.001) was not increased by pancreatic oxygenation (II vs. IV, NS). Conclusions: The present study suggests that pancreas short-term storage in oxygenated PFD improves in vitro but not the in vivo function of ischemically damaged pig islets.
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- Goto, Masafumi, et al.
(författare)
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Dissecting the instant blood-mediated inflammatory reaction in islet xenotransplantation
- 2008
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Ingår i: Xenotransplantation. - : Wiley. - 0908-665X .- 1399-3089. ; 15:4, s. 225-234
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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- Groth, CG
(författare)
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Looking back, heading forward
- 2008
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Ingår i: Xenotransplantation. - : Wiley. - 1399-3089 .- 0908-665X. ; 15:1, s. 1-2
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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- Hårdstedt, Maria, 1971-, et al.
(författare)
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Post‐transplant upregulation of chemokine messenger RNA in non‐human primate recipients of intraportal pig islet xenografts
- 2005
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Ingår i: Xenotransplantation. - : John Wiley & Sons. - 0908-665X .- 1399-3089. ; 12:4, s. 293-302
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: We have previously shown that pig-to-primate intraportal islet xenografts reverse diabetes, escape hyperacute rejection, and undergo acute cellular rejection in non-immunosuppressed recipients. To gain a better understanding of mechanisms contributing to xenoislet rejection in non-human primates we examined gene expression in livers bearing islet xenografts in the first 72 h after transplantation.METHODS: Liver specimens were collected at sacrifice from seven non-immunosuppressed rhesus macaques at 12, 24, 48 and 72 h after intraportal porcine islet transplantation. Following total RNA extraction, mRNA was quantified using SYBR green real-time reverse transcription polymerase chain reaction (RT-PCR) for species-specific immune response genes. Data were analyzed using comparative cycle threshold (Ct) analysis, adjusted for specific primer-efficiencies and normalized to cyclophilin expression.RESULTS: Porcine insulin mRNA was detected in all liver samples. Cluster analysis revealed differential gene expression patterns at 12 and 24 h (early) compared with at 48 and 72 h (late) post-transplant. Gene expression patterns were associated with histological findings of predominantly neutrophils and only a few lymphocytes at 12 and 24 h and an increasing number of lymphocytes and macrophages at 48 and 72 h. Transcript levels of CXCR3 and its ligands, interferon-inducible protein 10 (IP-10) and monokine induced by IFN-gamma (Mig), significantly increased between early and late time points together with expression of MIP-1alpha, regulated on activation normal T expressed and secreted protein (RANTES) and MCP-1. CCR5 showed only a marginal, non-significant increase. Fas ligand, perforin and granzyme B transcripts were all elevated at 48 and 72 h post-transplant.CONCLUSIONS: Our data suggest that CXCR3, with ligands IP-10 and Mig, is involved in T cell recruitment in acute islet xenograft rejection in non-human primates. Upregulation of RANTES and MIP-1alpha transcripts in the absence of a significant CCR5 increase suggests a possible involvement of other chemokine receptors. MCP-1 expression is associated with T cell and macrophage infiltration. Elevated cytotoxic effector molecule expression (Fas ligand, perforin, granzyme B) indicates T-cell mediated graft destruction by cytotoxic and cytolytic mechanisms within 48 to 72 h after transplantation. These results identify the CXCR3-mediated chemoattractant pathway as an immunosuppressive target in pig-to-primate islet xenotransplantation.
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