Challenges facing in vivo tracking of mesenchymal stem cells used for tissue regeneration

Abstract

Evaluation of: Li X-X, Li K-A, Qin J-B et al. In vivo MRI tracking of iron oxide nanoparticle-labeled human mesenchymal stem cells in limb ischemia. Int. J. Nanomedicine 8, 1063–1073 (2013).

Bone marrow-derived mesenchymal stem cells (MSCs) are increasingly being investigated in the field of regenerative medicine. In vivo monitoring of MSCs can be performed with MRI, which is a non-invasive, non-toxic and clinically acceptable modality. In order to track these MSCs, cells must be labeled with detectable magnetic nanoparticles. However, they ‘leak’ from labeled cells, limiting their surveillance to a 3-week period. Li et al. developed a rodent model in order to evaluate MRI monitoring of intramuscularly injected aminopropyltriethoxysilane iron oxide-labeled MSCs. Both in vivo tracking and histological analysis were undertaken. Seeded MSCs demonstrated increased MRI signal in the labeled test group over 3 weeks compared with the unlabeled controls. Histological Prussian blue staining of posttermination tissues confirmed these findings. The authors conclude that successful labeling of MSCs is possible with aminopropyltriethoxysilane – magnetic nanoparticles and that these cells can be monitored in vivo. They offer this form of labeling as an alternative to more common dextran-coated magnetic nanoparticles.

Keywords::

• bioluminescence
• magnetic resonance imaging
• mesenchymal stem cells
• single positron emission topography
• surveillance
• tissue repair
• tracking

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• MRI surveillance of mesenchymal stem cells (MSCs) can be performed by labeling cells with aminopropyltriethoxysilane-modified magnetic nanoparticles.

• Labeled MSCs with aminopropyltriethoxysilane-modified magnetic nanoparticles can only be tracked for up to 3 weeks.

• Other tracking modalities include bioluminescence imaging, positron emission tomography, single photon emission computerized tomography and quantum dots

• The ideal imaging technique for the in vivo surveillance of MSCs must be non-toxic, reproducible and exhibit long-term survivability.

• The expanding use of MSCs will hopefully lead to rapid development of better imaging strategies.