Assessment of 18F-FDG-leukocyte imaging to monitor rejection after pancreatic islet transplantation.
OBJECTIVE
We sought to investigate the feasibility of 18F-FDG-leukocyte imaging to detect islet rejection.


METHODS
Two thousand Sprague-Dawley (SD, syngeneic group) or Lewis (allogeneic group) islet equivalents were intraportally injected into SD rat recipients. Four and 7 days after transplantation, 10(8) 18F-FDG-labeled splenocytes were injected into the jugular vein. Splenocytes were harvested from naïve or sensitized (12 days after intraportal transplantation of 2000 Lewis IEQ) SD rats. Positron emission tomography (PET) imaging was started 5 minutes after splenocyte infusion and performed hourly for 4 hours.


RESULTS
One hour after splenocyte injection, FDG was mainly detected in the heart and lungs. It was then further distributed to other organs, and from the second hour, the highest tracer concentration was located in the abdomen. Liver FDG uptake was similar between syngeneic, allogeneic, and sensitized allogeneic groups at 4 and 7 days after islet transplantation.


CONCLUSIONS
No islet rejection was detected by 18F-FDG-leukocyte imaging. The amount of transplanted tissue was only few millilitres and the additional related inflammation in case of rejection is small and difficult to detect. The liver showed a relatively high spontaneous tracer uptake; the related background prevented detection of a potential increase in tracer uptake in cases of islet rejection.
Toso
C
C
Cell Isolation and Transplantation Center, Clinic for Visceral and Transplant Surgery, University Hospital, Geneva, Switzerland. christian.toso@hcuge.ch
Zaidi
H
H
Morel
P
P
Armanet
M
M
Wojtusciszyn
A
A
Mai
G
G
Baertschiger
R
R
Buhler
L
L
Berney
T
T
D000818:Animals; D019788:Fluorodeoxyglucose F18; D006084:Graft Rejection / Q000000981:diagnostic imaging*; D016381:Islets of Langerhans Transplantation / Q000276:immunology*; D008099:Liver / Q000000981:diagnostic imaging; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D051381:Rats; D011917:Rats, Inbred Lew; D017207:Rats, Sprague-Dawley; D014184:Transplantation, Homologous; D014185:Transplantation, Isogeneic
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18