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Labeling of mesenchymal stem cells for MRI with single-cell sensitivity.

Ariza de Schellenberger A, Kratz H, Farr TD, Löwa N, Hauptmann R, Wagner S, Taupitz M, Schnorr J, Schellenberger EA - Int J Nanomedicine (2016)

Bottom Line: Attempts should be made to achieve better cell separation for homogeneous NP loading and to thus improve NP-uptake-dependent biocompatibility studies and cell detection by MRI and future MPI.Additionally, using a 7 T MR imager equipped with a cryocoil resulted in approximately two times higher detection.In conclusion, we established labeling conditions for new high-relaxivity MCP, VSOP, and Resovist(®) for improved MRI of MSC with single-cell sensitivity.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Center for Stroke Research Berlin, Charité - Universitätsmedizin Berlin, Berlin, Germany.

ABSTRACT
Sensitive cell detection by magnetic resonance imaging (MRI) is an important tool for the development of cell therapies. However, clinically approved contrast agents that allow single-cell detection are currently not available. Therefore, we compared very small iron oxide nanoparticles (VSOP) and new multicore carboxymethyl dextran-coated iron oxide nanoparticles (multicore particles, MCP) designed by our department for magnetic particle imaging (MPI) with discontinued Resovist(®) regarding their suitability for detection of single mesenchymal stem cells (MSC) by MRI. We achieved an average intracellular nanoparticle (NP) load of >10 pg Fe per cell without the use of transfection agents. NP loading did not lead to significantly different results in proliferation, colony formation, and multilineage in vitro differentiation assays in comparison to controls. MRI allowed single-cell detection using VSOP, MCP, and Resovist(®) in conjunction with high-resolution T2*-weighted imaging at 7 T with postprocessing of phase images in agarose cell phantoms and in vivo after delivery of 2,000 NP-labeled MSC into mouse brains via the left carotid artery. With optimized labeling conditions, a detection rate of ~45% was achieved; however, the experiments were limited by nonhomogeneous NP loading of the MSC population. Attempts should be made to achieve better cell separation for homogeneous NP loading and to thus improve NP-uptake-dependent biocompatibility studies and cell detection by MRI and future MPI. Additionally, using a 7 T MR imager equipped with a cryocoil resulted in approximately two times higher detection. In conclusion, we established labeling conditions for new high-relaxivity MCP, VSOP, and Resovist(®) for improved MRI of MSC with single-cell sensitivity.

No MeSH data available.


Related in: MedlinePlus

Prussian Blue stain for mesenchymal stem cells labeled with Resovist®.Notes: Incubation at 0.2 mM Fe with protamine sulfate (A). Incubation of Resovist® at 2 mM Fe without protamine sulfate (B) resulted in higher NP uptake compared to (A). High amounts of extracellular iron are visible after both treatments (A and B). Extracellular matrix disruption and passage removed extracellular nanoparticles, allowing identification of true NP uptake (C and D). Insets a–d show corresponding images with higher magnification (40×). All scale bars correspond to 500 µm. Quantification of average Fe per cell (pg) revealed similar results for MSC labeled with MCP and VSOP (E).Abbreviations: ECM, extracellular matrix; MCP, multicore carboxy-methyl-dextran-coated iron oxide nanoparticle; NP, nanoparticle; VSOP, very small iron oxide nanoparticle.
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f1-ijn-11-1517: Prussian Blue stain for mesenchymal stem cells labeled with Resovist®.Notes: Incubation at 0.2 mM Fe with protamine sulfate (A). Incubation of Resovist® at 2 mM Fe without protamine sulfate (B) resulted in higher NP uptake compared to (A). High amounts of extracellular iron are visible after both treatments (A and B). Extracellular matrix disruption and passage removed extracellular nanoparticles, allowing identification of true NP uptake (C and D). Insets a–d show corresponding images with higher magnification (40×). All scale bars correspond to 500 µm. Quantification of average Fe per cell (pg) revealed similar results for MSC labeled with MCP and VSOP (E).Abbreviations: ECM, extracellular matrix; MCP, multicore carboxy-methyl-dextran-coated iron oxide nanoparticle; NP, nanoparticle; VSOP, very small iron oxide nanoparticle.

Mentions: As expected, our initial experiments showed that Resovist®, MCP, and VSOP uptake by MSC increased with incubation time (4 hours vs 24 hours, data not shown). We therefore continued with a 24-hour protocol, wherein NP uptake was up to three-fold higher in comparison to 4-hour protocols, in a particle-dependent manner. The results for 24-hour labeling are presented in Figure 1.


Labeling of mesenchymal stem cells for MRI with single-cell sensitivity.

Ariza de Schellenberger A, Kratz H, Farr TD, Löwa N, Hauptmann R, Wagner S, Taupitz M, Schnorr J, Schellenberger EA - Int J Nanomedicine (2016)

Prussian Blue stain for mesenchymal stem cells labeled with Resovist®.Notes: Incubation at 0.2 mM Fe with protamine sulfate (A). Incubation of Resovist® at 2 mM Fe without protamine sulfate (B) resulted in higher NP uptake compared to (A). High amounts of extracellular iron are visible after both treatments (A and B). Extracellular matrix disruption and passage removed extracellular nanoparticles, allowing identification of true NP uptake (C and D). Insets a–d show corresponding images with higher magnification (40×). All scale bars correspond to 500 µm. Quantification of average Fe per cell (pg) revealed similar results for MSC labeled with MCP and VSOP (E).Abbreviations: ECM, extracellular matrix; MCP, multicore carboxy-methyl-dextran-coated iron oxide nanoparticle; NP, nanoparticle; VSOP, very small iron oxide nanoparticle.
© Copyright Policy
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4835118&req=5

f1-ijn-11-1517: Prussian Blue stain for mesenchymal stem cells labeled with Resovist®.Notes: Incubation at 0.2 mM Fe with protamine sulfate (A). Incubation of Resovist® at 2 mM Fe without protamine sulfate (B) resulted in higher NP uptake compared to (A). High amounts of extracellular iron are visible after both treatments (A and B). Extracellular matrix disruption and passage removed extracellular nanoparticles, allowing identification of true NP uptake (C and D). Insets a–d show corresponding images with higher magnification (40×). All scale bars correspond to 500 µm. Quantification of average Fe per cell (pg) revealed similar results for MSC labeled with MCP and VSOP (E).Abbreviations: ECM, extracellular matrix; MCP, multicore carboxy-methyl-dextran-coated iron oxide nanoparticle; NP, nanoparticle; VSOP, very small iron oxide nanoparticle.
Mentions: As expected, our initial experiments showed that Resovist®, MCP, and VSOP uptake by MSC increased with incubation time (4 hours vs 24 hours, data not shown). We therefore continued with a 24-hour protocol, wherein NP uptake was up to three-fold higher in comparison to 4-hour protocols, in a particle-dependent manner. The results for 24-hour labeling are presented in Figure 1.

Bottom Line: Attempts should be made to achieve better cell separation for homogeneous NP loading and to thus improve NP-uptake-dependent biocompatibility studies and cell detection by MRI and future MPI.Additionally, using a 7 T MR imager equipped with a cryocoil resulted in approximately two times higher detection.In conclusion, we established labeling conditions for new high-relaxivity MCP, VSOP, and Resovist(®) for improved MRI of MSC with single-cell sensitivity.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Center for Stroke Research Berlin, Charité - Universitätsmedizin Berlin, Berlin, Germany.

ABSTRACT
Sensitive cell detection by magnetic resonance imaging (MRI) is an important tool for the development of cell therapies. However, clinically approved contrast agents that allow single-cell detection are currently not available. Therefore, we compared very small iron oxide nanoparticles (VSOP) and new multicore carboxymethyl dextran-coated iron oxide nanoparticles (multicore particles, MCP) designed by our department for magnetic particle imaging (MPI) with discontinued Resovist(®) regarding their suitability for detection of single mesenchymal stem cells (MSC) by MRI. We achieved an average intracellular nanoparticle (NP) load of >10 pg Fe per cell without the use of transfection agents. NP loading did not lead to significantly different results in proliferation, colony formation, and multilineage in vitro differentiation assays in comparison to controls. MRI allowed single-cell detection using VSOP, MCP, and Resovist(®) in conjunction with high-resolution T2*-weighted imaging at 7 T with postprocessing of phase images in agarose cell phantoms and in vivo after delivery of 2,000 NP-labeled MSC into mouse brains via the left carotid artery. With optimized labeling conditions, a detection rate of ~45% was achieved; however, the experiments were limited by nonhomogeneous NP loading of the MSC population. Attempts should be made to achieve better cell separation for homogeneous NP loading and to thus improve NP-uptake-dependent biocompatibility studies and cell detection by MRI and future MPI. Additionally, using a 7 T MR imager equipped with a cryocoil resulted in approximately two times higher detection. In conclusion, we established labeling conditions for new high-relaxivity MCP, VSOP, and Resovist(®) for improved MRI of MSC with single-cell sensitivity.

No MeSH data available.


Related in: MedlinePlus