In Vivo Imaging of Immune Rejection in Transplanted Pancreatic Islets

  1. Natalia V. Evgenov1,
  2. Zdravka Medarova1,
  3. John Pratt1,
  4. Pamela Pantazopoulos1,
  5. Simone Leyting1,
  6. Susan Bonner-Weir2 and
  7. Anna Moore1
  1. 1Department of Radiology, Molecular Imaging Laboratory, Massachusetts General Hospital/Massachusetts Institute of Technology/Harvard Medical School Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
  2. 2Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts
  1. Address correspondence and reprint requests to Anna Moore, PhD, Molecular Imaging Laboratory, MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital/Harvard Medical School, Rm. 2301, Bldg. 149, 13th St., Charlestown, MA 02129. E-mail: amoore{at}helix.mgh.harvard.edu

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.

Footnotes

  • Z.M. and J.P. contributed equally to this work.

    Additional information for this article can be found in an online appendix at http://diabetes.diabetesjournals.org.

    The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

    • Accepted June 16, 2006.
    • Received April 11, 2006.
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