title: In vivo imaging of immune rejection in transplanted pancreatic islets.
abstract: As islet transplantation becomes an acceptable clinical modality for restoring normoglycemia in type 1 diabetic patients, there is a crucial need for noninvasive assessment of the fate of the grafts. In spite of the success of the Edmonton Protocol, a significant graft loss occurs due to immunological and nonimmunological events immediately after transplantation. Allogeneic rejection in graft recipients is one of the major reasons for islet death and graft failure. Therefore, monitoring the islet rejection using reliable noninvasive methods would significantly aid in clinical assessment of graft success. We have previously developed a method to detect transplanted islets noninvasively using magnetic resonance imaging (MRI). For this procedure, human pancreatic islets are labeled with an MRI contrast agent that enables their visualization on magnetic resonance images. In our present study, we not only detected labeled human islets in a preclinical intrahepatic model of human islet transplantation in mice but also showed that islet rejection can be monitored noninvasively and repeatedly in real time by MRI. In addition, in this study, we have adapted, for islet cell labeling, a Food and Drug Administration-approved commercially available contrast agent, Feridex, that is used clinically for liver imaging. We believe that this agent, in combination with our preclinical model of islet transplantation, will facilitate the transition of imaging immune rejection to clinical trials.
authors.affiliation: Molecular Imaging Laboratory, Department of Radiology, Massachusetts General Hospital/Massachusetts Institute of Technology/Harvard Medical School, Charlestown, MA 02129, USA.
authors.forename: Natalia V
authors.initials: NV
authors.lastname: Evgenov
authors.forename: Zdravka
authors.initials: Z
authors.lastname: Medarova
authors.forename: John
authors.initials: J
authors.lastname: Pratt
authors.forename: Pamela
authors.initials: P
authors.lastname: Pantazopoulos
authors.forename: Simone
authors.initials: S
authors.lastname: Leyting
authors.forename: Susan
authors.initials: S
authors.lastname: Bonner-Weir
authors.forename: Anna
authors.initials: A
authors.lastname: Moore
mesh_terms: D000818:Animals; D003287:Contrast Media; D003911:Dextrans; D003922:Diabetes Mellitus, Type 1 / Q000601:surgery; D052203:Ferrosoferric Oxide; D006084:Graft Rejection / Q000276:immunology*; D006651:Histocytochemistry; D006801:Humans; D007501:Iron / Q000378:metabolism; D007515:Islets of Langerhans / Q000378:metabolism; D016381:Islets of Langerhans Transplantation / Q000276:immunology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles; D051379:Mice; D008807:Mice, Inbred BALB C; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D010087:Oxides / Q000378:metabolism
chemical_list: D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; D007501:Iron; C065507:ferumoxides; D052203:Ferrosoferric Oxide