title: Positron emission tomography: a real-time tool to quantify early islet engraftment in a preclinical large animal model.
abstract: BACKGROUND
  Clinical islet transplantation is currently being explored as a therapeutic option for persons with type I diabetes and hypoglycemic unawareness. Techniques to monitor graft survival are urgently needed to optimize the procedure. Therefore, the objective of the present study was to develop a technique for imaging survival of transplanted islets in the peritransplant and early posttransplant phase.
  
  
  METHODS
  Isolated porcine islets were labeled in vitro with 2-deoxy-2[F]fluoro-D-glucose ([F]FDG) and infused intraportally into anesthetized pigs (n=10). Dynamic examination was performed on a positron emission tomography/computed tomography hybrid system.
  
  
  RESULTS
  More than 95% of the radioactivity was confined to the islets at the time of transplantation. The peak percentage of infused radioactivity within the liver, quantified at the end of the islet infusion, was only 54+/-5.1%. The distribution of the radioactivity in the liver was found to be heterogeneous. A whole-body examination showed no accumulation in the lungs or brain; extrahepatic radioactivity was, except urinary excretion, evenly distributed in the pig body.
  
  
  CONCLUSIONS
  Our results imply that almost 50% of the islets were damaged to the extent that the FDG contained was release within minutes after intraportal transplantation. The distribution of radioactivity without accumulation in the brain indicates that the activity is released from lysed islet cells in the form of [F]FDG-6P rather than native [F]FDG. The presented technique shows promise to become a powerful and quantitative tool, readily available in the clinic, to evaluate initial islet engraftment and survival.
authors.affiliation: Department of Radiology, Oncology and Clinical Immunology, Division of Clinical Immunology, University Hospital, Uppsala, Sweden.
authors.forename: Torsten
authors.initials: T
authors.lastname: Eich
authors.forename: Olof
authors.initials: O
authors.lastname: Eriksson
authors.forename: Anders
authors.initials: A
authors.lastname: Sundin
authors.forename: Sergio
authors.initials: S
authors.lastname: Estrada
authors.forename: Daniel
authors.initials: D
authors.lastname: Brandhorst
authors.forename: Heide
authors.initials: H
authors.lastname: Brandhorst
authors.forename: Bengt
authors.initials: B
authors.lastname: Langstrom
authors.forename: Bo
authors.initials: B
authors.lastname: Nilsson
authors.forename: Olle
authors.initials: O
authors.lastname: Korsgren
authors.forename: Torbjorn
authors.initials: T
authors.lastname: Lundgren
mesh_terms: D000818:Animals; D001345:Autoradiography; D003952:Diagnostic Imaging / Q000379:methods / Q000639:trends; D004195:Disease Models, Animal; D005947:Glucose / Q000378:metabolism; D006085:Graft Survival; D007515:Islets of Langerhans / Q000166:cytology* / Q000378:metabolism; D016381:Islets of Langerhans Transplantation / Q000379:methods*; D049268:Positron-Emission Tomography / Q000379:methods*; D013552:Swine; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D005947:Glucose