PURPOSE: In order to evaluate future β cell tracers in vivo, we aimed to develop a standardized in vivo method allowing semiquantitative measurement of a prospective β cell tracer within the pancreas. PROCEDURES: 2-[(123)I]Iodo-L-phenylalanine ([(123)I]IPA) and [Lys(40)([(111)In]DTPA)]exendin-3 ([(111)In]Ex3) pancreatic uptake and biodistribution were evaluated using SPECT, autoradiography, and an ex vivo biodistribution study in a controlled unilaterally nephrectomized mouse β cell depletion model. Semiquantitative measurement of the imaging results was performed using [(123)I]IPA to delineate the pancreas and [(111)In]Ex3 as a β cell tracer. RESULTS: The uptake of [(123)I]IPA was highest in the pancreas. Aside from the kidneys, the uptake of [(111)In]Ex3 was highest in the pancreas and lungs. Autoradiography showed only uptake of [(111)In]Ex3 in insulin-expressing cells. Semiquantitative measurement of [(111)In]Ex3 in the SPECT images based on the delineation of the pancreas with [(123)I]IPA showed a high correlation with the [(111)In]Ex3 uptake data of the pancreas obtained by dissection. A strong positive correlation was observed between the relative insulin positive area and the pancreas-to-blood ratios of [(111)In]Ex3 uptake as determined by counting with a gamma counter and the semiquantitative analysis of the SPECT images. CONCLUSIONS: [(123)I]IPA is a promising tracer to delineate pancreatic tissue on SPECT images. It shows a high uptake in the pancreas as compared to other abdominal tissues. This study also demonstrates the feasibility and accuracy to measure the β cell mass in vivo in an animal model of diabetes.
PURPOSE: In order to evaluate future β cell tracers in vivo, we aimed to develop a standardized in vivo method allowing semiquantitative measurement of a prospective β cell tracer within the pancreas. PROCEDURES: 2-[(123)I]Iodo-L-phenylalanine ([(123)I]IPA) and [Lys(40)([(111)In]DTPA)]exendin-3 ([(111)In]Ex3) pancreatic uptake and biodistribution were evaluated using SPECT, autoradiography, and an ex vivo biodistribution study in a controlled unilaterally nephrectomized mouse β cell depletion model. Semiquantitative measurement of the imaging results was performed using [(123)I]IPA to delineate the pancreas and [(111)In]Ex3 as a β cell tracer. RESULTS: The uptake of [(123)I]IPA was highest in the pancreas. Aside from the kidneys, the uptake of [(111)In]Ex3 was highest in the pancreas and lungs. Autoradiography showed only uptake of [(111)In]Ex3 in insulin-expressing cells. Semiquantitative measurement of [(111)In]Ex3 in the SPECT images based on the delineation of the pancreas with [(123)I]IPA showed a high correlation with the [(111)In]Ex3 uptake data of the pancreas obtained by dissection. A strong positive correlation was observed between the relative insulin positive area and the pancreas-to-blood ratios of [(111)In]Ex3 uptake as determined by counting with a gamma counter and the semiquantitative analysis of the SPECT images. CONCLUSIONS: [(123)I]IPA is a promising tracer to delineate pancreatic tissue on SPECT images. It shows a high uptake in the pancreas as compared to other abdominal tissues. This study also demonstrates the feasibility and accuracy to measure the β cell mass in vivo in an animal model of diabetes.
Authors: Martin Gotthardt; Georg Lalyko; Julliëtte van Eerd-Vismale; Boris Keil; Tino Schurrat; Michael Hower; Peter Laverman; Thomas M Behr; Otto C Boerman; Burkhard Göke; Martin Béhé Journal: Regul Pept Date: 2006-08-22
Authors: Marie-Line Peyot; Emilie Pepin; Julien Lamontagne; Martin G Latour; Bader Zarrouki; Roxane Lussier; Marco Pineda; Thomas L Jetton; S R Murthy Madiraju; Erik Joly; Marc Prentki Journal: Diabetes Date: 2010-06-14 Impact factor: 9.461
Authors: Stefanie M A Willekens; Lieke Joosten; Otto C Boerman; Alexander Balhuizen; Decio L Eizirik; Martin Gotthardt; Maarten Brom Journal: Mol Imaging Biol Date: 2016-10 Impact factor: 3.488