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Po‐Thur Eve General‐22: 111In‐Tropolone‐Labeled Mesenchymal Stem Cells: In Vivo Radiotracer Kinetics
Author(s) -
Jin Y,
Kong H,
Wells G,
Sykes J,
Prato F
Publication year - 2006
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.2244649
Subject(s) - tropolone , mesenchymal stem cell , in vivo , transplantation , chemistry , stem cell , in vitro , biodistribution , kinetics , cell , nuclear medicine , microbiology and biotechnology , pathology , biology , medicine , biochemistry , physics , organic chemistry , quantum mechanics
Direct in vitro labeling of cells with111 In ‐tropolone followed by in vivo SPECT imaging gives no information about the fate of the cells but simply tells where the111 In has gone. It is necessary to study the kinetics of111 In label after transplantation and determine the connection between111 In and the presence of viable cells. Two sets (n=5) of mesenchymal stem cells (MSC) were labeled with111 In ‐tropolone and then killed by using an ultrasound probe to rupture the cell membrane or by freezing the cells at −80°C for 60min. The resulting cell debris and supernatant were used to label two new sets of MSC. The labeling efficiency was measured and compared to a control labeled with111 In ‐tropolone. 1.5×10 7 MSC labeled with 1.32MBq111 In were killed using the ultrasound probe and then injected into the myocardium of a canine (without infarction). Whole body and SPECT images were acquired over 13 hrs post‐injection. The animal was then sacrificed and the amount of111 In remaining in tissue samples from the heart was measured. (0.2±0.5)% and (0.3±0.5)% labeling efficiencies were found for cells labeled with ultrasound‐killed and frozen‐killed cells, while the labeling efficiency of the control cells was found to be (53.0±2.0)% for a 30min cell culture. After 13hrs, <4% of injected111 In remained in the myocardium. Analysis of the111 In SPECT images indicated a biological half‐life of 2.3 hours. It was concluded that111 In leaked from dead MSC does not label other viable MSC and will be rapidly cleared from the myocardium.