| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
|
|
|||||||||
|
|
Cardiovascular: Basic ScienceMolecular Targeting - Plaques and Stem Cells |
1 Medical Biophysics, University of Western Ontario, London, Ontario, Canada; 2 Imaging Program, Lawson Health Research Institute, London, Ontario, Canada
113
Objectives: Imaging survival after clinical cell transplantation in the myocardium is largely hampered by the lack of clinically available quantitative techniques. We describe a method to image transplanted cell (TC) survival with 111In-tropolone and SPECT in canine myocardium.
Methods: Quantitation was based on a model that corrected for extracellular 111-Indium resulting from radiolabel leakage and death. In vivo myocardial dead TC clearance was obtained from cells labeled in vitro with 111In-tropolone and lysed prior to transplantation (n=11). Clearance due to leakage was determined by labeling normal cardiomyocytes with 111In-tropolone in situ (n=2). Lastly, 111In labeled TC’s were transplanted into the border infarct region of LAD occluded/reperfused canines (n=4). All canines had intramyocardial injections following thoracotomy, after which SPECT was acquired to generate time activity curves.
Results: Clearance of labeled cellular debris had a biological half-life (Tb) of 19.4±4.1 hours. Comparatively, Tb from in situ 111In-tropolone injections was significantly longer (465±71 hours; p<0.05) and revealed a leakage rate of 0.11%/hour. Hence, Tb of 111In-labeled TC can be measured with 10% accuracy for values between 19-465 hours. In the 4 animals the Tb was 77.2±4.7 hours, which when corrected for the delayed clearance effects of leakage and cell debris, was estimated at 78.8 hours.
Conclusions: SPECT can quantitatively assess TC survival with 111In in canine myocardium when appropriate corrections are applied.
| ||||||||||||||||||||||||||||||||||||||
