Effect of the intracellular localization of a Gd-based imaging probe on the relaxation enhancement of water protons.
Gd-HPDO3A has been internalized into rat hepatocarcinoma cells in the cytoplasm (by electroporation) or in intracellular vesicles (by pinocytosis), respectively. In the former case, the observed relaxation rates are likely dependent upon the amount of internalized paramagnetic complex, whereas in the latter case the relaxation enhancement is "quenched" to a plateau value (about 3 s(-1)) when the entrapped amount of Gd-chelate is higher than 1 x 10(10) Gd/cell. The observed behavior has been accounted in terms of a theoretical treatment based on equations formally derived by Labadie et al. (J Magn Reson B 1994;105:99-102). On this basis, entrapment into intracellular vesicles has been treated as a three-site water exchange (extracellular/cytoplasm/vesicle compartments), whereas the cell pellets containing the paramagnetic agent spread out in the cytoplasm can be analyzed by a two-site exchange system.
Terreno
Enzo
E
Department of Chemistry, I.F.M., and Center for Molecular Imaging (CIM), University of Torino, Torino, Italy.
Geninatti Crich
Simonetta
S
Belfiore
Simona
S
Biancone
Luigi
L
Cabella
Claudia
C
Esposito
Giovanna
G
Manazza
Andrea D
AD
Aime
Silvio
S
D000818:Animals; D002468:Cell Physiological Phenomena; D002614:Chelating Agents; D018274:Electroporation; D005682:Gadolinium; D006571:Heterocyclic Compounds; D017136:Ion Transport; D008279:Magnetic Resonance Imaging; D015388:Organelles; D009942:Organometallic Compounds; D010873:Pinocytosis; D051381:Rats; D014407:Tumor Cells, Cultured; D014867:Water / Q000378:metabolism
D002614:Chelating Agents; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; C062402:gadoteridol; D014867:Water; D005682:Gadolinium