title: Characterizing the Mechanistic Pathways of the Instant Blood-Mediated Inflammatory Reaction in Xenogeneic Neonatal Islet Cell Transplantation.
abstract: BACKGROUND
  The instant blood-mediated inflammatory reaction (IBMIR) causes major loss of islets after transplantation and consequently represents the initial barrier to survival of porcine neonatal islet cell clusters (NICC) after xenotransplantation.
  
  
  METHODS
  This study used novel assays designed to characterize the various immunologic components responsible for xenogeneic IBMIR to identify initiators and investigate processes of IBMIR-associated coagulation, complement activation and neutrophil infiltration. The IBMIR was induced in vitro by exposing NICC to platelet-poor or platelet-rich human plasma or isolated neutrophils.
  
  
  RESULTS
  We found that xenogeneic IBMIR was characterized by rapid, platelet-independent thrombin generation, with addition of platelets both accelerating and exacerbating this response. Platelet-independent complement activation was observed as early as 30 minutes after NICC exposure to plasma. However, membrane attack complex formation was not observed in NICC histopathology sections until after 60 minutes. We demonstrated for the first time that NICC-mediated complement activation was necessary for neutrophil activation in the xenogeneic IBMIR setting. Finally, using the Seahorse extracellular flux analyzer, we identified substantial loss of islet function (up to 40%) after IBMIR with surviving NICC showing evidence of mitochondrial damage.
  
  
  CONCLUSIONS
  This study used novel assays to describe multiple key pathways by which xenogeneic IBMIR causes islet destruction, allowing further refinement of future interventions aimed at resolving the issue of IBMIR in xenotransplantation.
authors: The Centre for Transplant & Renal Research, The Westmead Institute, Westmead, NSW, Australia.; University of Sydney at Westmead Hospital, Westmead, NSW, Australia.
authors: David
authors: D
authors: Liuwantara
authors: The Centre for Transplant & Renal Research, The Westmead Institute, Westmead, NSW, Australia.
authors: Yi Vee
authors: YV
authors: Chew
authors: Sydney Centres for Thrombosis and Haemostasis, ICPMR, Westmead Hospital, Westmead, NSW, Australia.
authors: Emmanuel J
authors: EJ
authors: Favaloro
authors: The Centre for Transplant & Renal Research, The Westmead Institute, Westmead, NSW, Australia.
authors: Joanne M
authors: JM
authors: Hawkes
authors: The Centre for Transplant & Renal Research, The Westmead Institute, Westmead, NSW, Australia.
authors: Heather L
authors: HL
authors: Burns
authors: The Centre for Transplant & Renal Research, The Westmead Institute, Westmead, NSW, Australia.; University of Sydney at Westmead Hospital, Westmead, NSW, Australia.
authors: Philip J
authors: PJ
authors: O'Connell
authors: The Centre for Transplant & Renal Research, The Westmead Institute, Westmead, NSW, Australia.; University of Sydney at Westmead Hospital, Westmead, NSW, Australia.
authors: Wayne J
authors: WJ
authors: Hawthorne