Positron Emission Tomography to Assess the Outcome of Intraportal Islet Transplantation

Diabetes. 2016 Sep;65(9):2482-9. doi: 10.2337/db16-0222. Epub 2016 Jun 20.


No imaging methodology currently exists to monitor viable islet mass after clinical intraportal islet transplantation. We investigated the potential of the endocrine positron emission tomography (PET) marker [(11)C]5-hydroxytryptophan ([(11)C]5-HTP) for this purpose. In a preclinical proof-of-concept study, the ex vivo and in vivo [(11)C]5-HTP signal was compared with the number of islets transplanted in rats. In a clinical study, human subjects with an intraportal islet graft (n = 8) underwent two [(11)C]5-HTP PET and MRI examinations 8 months apart. The tracer concentration in the liver as a whole, or in defined hotspots, was correlated to measurements of islet graft function. In rat, hepatic uptake of [(11)C]5-HTP correlated with the number of transplanted islets. In human subjects, uptake in hepatic hotspots showed a correlation with metabolic assessments of islet function. Change in hotspot standardized uptake value (SUV) predicted loss of graft function in one subject, whereas hotspot SUV was unchanged in subjects with stable graft function. The endocrine marker [(11)C]5-HTP thus shows a correlation between hepatic uptake and transplanted islet function and promise as a tool for noninvasive detection of viable islets. The evaluation procedure described can be used as a benchmark for novel agents targeting intraportally transplanted islets.

Trial registration: ClinicalTrials.gov NCT02689479.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 5-Hydroxytryptophan / analysis
  • Animals
  • Diabetes Mellitus, Type 1 / diagnostic imaging
  • Healthy Volunteers
  • Humans
  • Islets of Langerhans Transplantation*
  • Liver / diagnostic imaging
  • Magnetic Resonance Imaging
  • Positron-Emission Tomography / methods*
  • Radiochemistry
  • Rats
  • Retrospective Studies


  • 5-Hydroxytryptophan

Associated data

  • ClinicalTrials.gov/NCT02689479