MRI assessment of ischemic liver after intraportal islet transplantation.
BACKGROUND
There is a recent focus on embolization of the portal vein by transplanted islets as a major cause of early graft loss. The resultant ischemia causes necrosis or apoptosis of cells within the liver. Thus, noninvasive assessment of the liver receiving the islet transplant is important to evaluate the status islet grafts.


METHODS
This study used noninvasive magnetic resonance imaging (MRI) for assessment of the posttransplant ischemic liver. Syngeneic islets in streprozotocin-induced diabetic mice were used. MRI and morphological liver assessments were performed at 0, 2, and 28 days after transplantation. Histologic assessment of insulin, hypoxia induced factor 1-alpha, and apoptosis were undertaken at similar time points.


RESULTS
Ischemic/necrotic regions in the liver were detected by MRI at 2 days but not at 28 days after transplantation and were confirmed histologically. Liver injury was quantified from high intensity areas on T2-weighted images. Insulin release peaked 2 days after transplantation.


CONCLUSIONS
Onset and reversal of liver ischemia due to intraportal islet transplantation are detectable using T2-weighted MRI. These changes coincide with periods of maximum insulin release likely due to partial islet destruction. We propose that MRI, as a noninvasive monitor of graft-related ischemia, may be useful in assessment of liver and islet engraftment after intraportal islet transplantation in a clinical setting.
Sakata
Naoaki
N
Department of Pediatrics, Islet Transplant Laboratory, Loma Linda University School of Medicine, CA, USA.
Hayes
Pete
P
Tan
Annie
A
Chan
Nathaniel K
NK
Mace
John
J
Peverini
Ricardo
R
Sowers
Lawrence
L
Pearce
William J
WJ
Chinnock
Richard
R
Obenaus
Andre
A
Hathout
Eba
E
D000818:Animals; D017209:Apoptosis; D001786:Blood Glucose / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000601:surgery*; D005260:Female; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000032:analysis; D007328:Insulin / Q000097:blood / Q000378:metabolism; D000078790:Insulin Secretion; D007511:Ischemia / Q000473:pathology*; D016381:Islets of Langerhans Transplantation / Q000009:adverse effects / Q000379:methods / Q000473:pathology*; D008099:Liver / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D051379:Mice; D008807:Mice, Inbred BALB C; D011169:Portal Vein / Q000473:pathology; D014185:Transplantation, Isogeneic
D001786:Blood Glucose; C497443:Hif1a protein, mouse; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D007328:Insulin