Relaxation effects of ferucarbotran-labeled mesenchymal stem cells at 1.5T and 3T: discrimination of viable from lysed cells.
Human mesenchymal stem cells (hMSCs) were labeled with Ferucarbotran by simple incubation and cultured for up to 14 d. Iron content was determined by spectrometry and the intracellular localization of the contrast agent uptake was studied by electron and confocal microscopy. At various time points after labeling, ranging from 1 to 14 d, samples with viable or lysed labeled hMSCs, as well as nonlabeled controls, underwent MRI. Spin-echo (SE) and gradient-echo (GE) sequences with multiple TRs and TEs were used at 1.5T and 3T on a clinical scanner. Spectrometry showed an initial iron oxide uptake of 7.08 pg per cell. Microscopy studies revealed lysosomal compartmentalization. Contrast agent effects of hMSCs were persistent for up to 14 d after labeling. A marked difference in the T(2) effect of compartmentalized iron oxides compared to free iron oxides was found on T(2)-weighted sequences, but not on T(2)*-weighted sequences. The observed differences may be explained by the loss of compartmentalization of iron oxide particles, the uniformity of distribution, and the subsequent increase in dephasing of protons on SE images. These results show that viable cells with compartmentalized iron oxides may-in principle-be distinguished from lysed cells or released iron oxides.
Department of Radiology, University of California, San Francisco (UCSF) Medical Center, UCSF, San Francisco, CA 94143-0628, USA.
Tobias D
TD
Henning
Michael F
MF
Wendland
Daniel
D
Golovko
Elizabeth J
EJ
Sutton
Barbara
B
Sennino
Farbod
F
Malek
Jan S
JS
Bauer
Donald M
DM
McDonald
Heike
H
Daldrup-Link
D002458:Cell Fractionation; D002478:Cells, Cultured; D003287:Contrast Media / Q000493:pharmacokinetics; D003911:Dextrans; D052203:Ferrosoferric Oxide / Q000493:pharmacokinetics*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism*; D012680:Sensitivity and Specificity; D013194:Staining and Labeling / Q000379:methods
D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; C065507:ferumoxides; D052203:Ferrosoferric Oxide